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Alpha-Lipoic acid protects against reperfusion injury following cerebral ischemia in rats
Abstract
Ischemic-reperfusion injury in humans occurs in conditions such as stroke, cardiac arrest, subarachnoid hemorrhage or head trauma. Maximal tissue damage is observed during reperfusion, which is primarily attributed to oxidative injury resulting from production of oxygen free radicals. One of the major consequences of such damage is the depletion of the cellular antioxidant, glutathione (GSH) leading to oxidation of protein thiols to disulfides and the loss of activity of critical enzymes having active thiol group(s). Thus, the maintenance of thiol homeostasis is an important factor in cell survival. The effect of thiol antioxidants like α-lipoic acid and the isopropyl ester of GSH was examined on the morbidity and mortality of rats subjected to reperfusion following cerebral ischemia induced by bilateral carotid artery occlusion and hypotension. While the GSH isopropyl ester had no significant protective effect; after pretreatment of rats, α-lipoic acid was detected in the rat brain and it dramatically reduced the mortality rate from 78% to 26% during 24 h of reperfusion. The natural thiol antioxidant, α-lipoic acid is effective in improving survival and protecting the rat brain against reperfusion injury following cerebral ischemia.
... Reperfusion following severe ischemia, induced by bilateral carotid artery occlusion and systemic hypotension results in massive loss of GSH along with an increased mortality rate [65]. Partial ischemia induced by bilateral carotid artery occlusion for 30 min reduces blood flow to 50%. ...
... Thus, the administration of thiol antioxidants such as α-lipoic acid was shown to restore and maintain thiol homeostasis to recover from reperfusion injury. α-lipoic acid shows a remarkable neuroprotective effect during severe ischemic-reperfusion injury with the mortality rate in rats reduced from 78% to 26% accompanied by attenuation of brain GSH loss [65]. ...
Oxidative stress has been implicated in the pathogenesis and progression of many neurodegenerative disorders including Parkinson’s disease and Alzheimer’s disease. One of the major enzyme systems involved in the defense against reactive oxygen species are the tripeptide glutathione and oxidoreductase glutaredoxin. Glutathione and glutaredoxin system are very important in the brain because of the oxidative modification of protein thiols to protein glutathione mixed disulfides with the concomitant formation of oxidized glutathione during oxidative stress. Formation of Pr-SSG acts as a sink in the brain and is reduced back to protein thiols during recovery, thus restoring protein functions. This is unlike in the liver, which has a high turnover of glutathione, and formation of Pr-SSG is very minimal as liver is able to quickly quench the prooxidant species. Given the important role glutathione and glutaredoxin play in the brain, both in normal and pathologic states, it is necessary to study ways to augment the system to help maintain the protein thiol status. This review details the importance of glutathione and glutaredoxin systems in several neurodegenerative disorders and emphasizes the potential augmentation of this system as a target to effectively protect the brain during aging.
... Previous in vivo studies on the neuroprotective effects of ALA have only looked at how it lowers oxidative stress. Given the increased usage of ALA by the general population, the aforementioned findings may be important in the therapeutic environment, In several animal models, ALA treatment has been shown to reduce infarct size (Panigrahi M, Sadguna Y, (1996); .These earlier studies assessed the effects of ALA pretreatment, ranging from a single acute injection to many daily injections for up to 30 days, Its efficiency in studies have been conducted on ALA (Panigrahi M, Sadguna Y) (1996). ...
... Previous in vivo studies on the neuroprotective effects of ALA have only looked at how it lowers oxidative stress. Given the increased usage of ALA by the general population, the aforementioned findings may be important in the therapeutic environment, In several animal models, ALA treatment has been shown to reduce infarct size (Panigrahi M, Sadguna Y, (1996); .These earlier studies assessed the effects of ALA pretreatment, ranging from a single acute injection to many daily injections for up to 30 days, Its efficiency in studies have been conducted on ALA (Panigrahi M, Sadguna Y) (1996). ...
Background: Alpha lipoic acid has both hydrophilic and hydrophobic characteristics and is abundantly distributed in cellular membranes and the cytoplasm. It is among the top cell- protective antioxidants. Material and methods : The present work investigated the possible therapeutic effects of alpha lipoic acid in a male rat model of brain aging induced by D-galactose. Four equal-sized groups of 40 male rats were randomly assigned: G1, the control group, G2, and G3, which each received daily doses of 200 mg/kg of D-gal for 30 days. Alpha lipoic acid was given orally for 30 days to the G4 D-gal + alpha lipoic acid group at 200 mg/kg bw, IP. daily with 100 mg/kg. thirty days of IP. Glutamate is deposited in the brain, according to research on behavioral alterations and brain glutamate. Indicators of oxidative stress are increased Our Results show that whereas brain glutamate deposition declines in the D-gal model of aging, the Forced Swimming Test (FST) and Morris Water Maze Test considerably rise (MWM).
... However, a differential activation of members of the MAPK's family has been observed in a CVI model in vivo [27] and after an OGD insult in vitro [28]. In those studies, MAPKs members such as ERK1/2 [27], JNK 1/2 [29] and p-38 [30] have been suggested to possess neuroprotective effects following ischemic brain injury. The protective or damaging effects on rescue or cell death by activation or suppression of MAPK members in different experimental modalities deserve careful investigations. ...
... Given its clinical safety, [29], α-LA is considered a potential molecule for CVI treatment. Early studies in both humans and experimental animal models found that α-LA can decrease redox potential markers of oxidative stress following stroke or traumatic brain damage [27,30]. Administration of α-LA to rodents has shown to reduce damage that occurs after ischemia-reperfusion injuries in the central [146] and peripheral nervous system [147]. ...
This review surveys the efforts taken to investigate in vitro neuroprotective features of synthetic compounds and cell-released growth factors on PC12 clonal cell line temporarily deprived of oxygen and glucose followed by reoxygenation (OGD/R). These cells have been used previously to mimic some of the properties of in vivo brain ischemia-reperfusion-injury (IRI) and have been instrumental in identifying common mechanisms such as calcium overload, redox potential, lipid peroxidation and MAPKs modulation. In addition, they were useful for establishing the role of certain membrane penetrable cocktails of antioxidants as well as potential growth factors which may act in neuroprotection. Pharmacological mechanisms of neuroprotection addressing modulation of the MAPK cascade and increased redox potential by natural products, drugs and growth factors secreted by stem cells, in either undifferentiated or nerve growth factor-differentiated PC12 cells exposed to ischemic conditions are discussed for future prospects in neuroprotection studies.
... Lipoic acid acts as a cofactor in mitochondrial α-keto acid dehydrogenase complexes in all eukaryotic and prokaryotic cells [27]. Previous studies demonstrated that exogenously supplied LA can pass through the blood brain barrier and accumulate in the brain [28,29]. These properties make LA a perfect antioxidant for the treatment of brain disease. ...
... Addition of LA to OGD/reoxygenationtreated cells resulted in significant increase of the viability of the cells and reduction of ROS levels. The current in vivo/ex vivo findings, in agreement with previous studies [28,35], demonstrate that LA could exert its neuroprotection through the attenuation of oxidative stress injury. ...
Background/aims:
Alpha-lipoic acid (α-LA) has been demonstrated to be protective against cerebral ischemia injury. Herein, we investigate the neuroprotective effect and underlying mechanisms of α-LA.
Methods:
In vivo study, α-LA was administered intravenously upon reperfusion of transient middle cerebral artery occlusion. Garcia score was used to evaluate neurologic recovery. Infarct volume was examined by TTC staining, and oxidative damage was evaluated by ELISA assay. In an in vitro study, neurons were pretreated with α-LA at different doses and then subjected to OGD. Lentiviral vectors were applied to knockdown nuclear factor-erythroid 2-related factor-2 (Nrf2) or heme oxygenase-1 (HO-1). Cell viability was measured using CCK8. Protein expression was evaluated using western blot, and immunofluorescence staining was assessed.
Results:
α-LA significantly reduced the infarct volume, brain edema, and oxidative damage and promoted neurologic recovery in rats. Pretreatment of α-LA caused an obvious increase in cell viability and a decrease in intracellular reactive oxygen species. Western blot analyses and immunofluorescence staining demonstrated a distinct increase in Nrf2 and HO-1 protein expression. Conversely, knockdown of Nrf2 or HO-1 resulted in the down-regulation of HO-1 protein and inhibited the neuroprotective effect of α-LA.
Conclusion:
α-LA treatment is neuroprotective and promotes functional recovery after ischemic stroke by attenuating oxidative damage, which is partially mediated by the Nrf2/HO-1 pathway.
... Alpha lipoic acid (ALA), a necessary cofactor for mitochondrial enzymes, is introduced as a new antioxidant and acts as free radical scavenger (Biewenga et al., 1997;Packer et al., 1995). This agent is used for neurodegenerative disorders, heavy metal toxicity, and oxidative tissue injury (Nagamatsu et al., 1995;Panigrahi et al., 1996). It also has therapeutic effects on diabetes, polyneuropathy, cataract, neurodegeneration, and nephropathies (Alegre et al., 2010;Amudha et al., 2007). ...
... It serves similar to lipoamid as a cofactor in the multienzyme system for catalysis of oxidative decarboxylation of α-keto acids (Marangon et al., 1999). ALA chelates platinum and prevents its accumulation in renal tissue in CDDP-induced nephrotoxicity (Nagamatsu et al., 1995;Panigrahi et al., 1996). Somani et al. have reported that increased Cr level induced by CDDP is improved after administration of graded doses of ALA (12, 50, 100 mg/kg) (Somani et al., 2000). ...
... Alpha lipoic acid (ALA), a necessary cofactor for mitochondrial enzymes, is introduced as a new antioxidant and acts as free radical scavenger (Biewenga et al., 1997;Packer et al., 1995). This agent is used for neurodegenerative disorders, heavy metal toxicity, and oxidative tissue injury (Nagamatsu et al., 1995;Panigrahi et al., 1996). It also has therapeutic effects on diabetes, polyneuropathy, cataract, neurodegeneration, and nephropathies (Alegre et al., 2010;Amudha et al., 2007). ...
... It serves similar to lipoamid as a cofactor in the multienzyme system for catalysis of oxidative decarboxylation of α-keto acids (Marangon et al., 1999). ALA chelates platinum and prevents its accumulation in renal tissue in CDDP-induced nephrotoxicity (Nagamatsu et al., 1995;Panigrahi et al., 1996). Somani et al. have reported that increased Cr level induced by CDDP is improved after administration of graded doses of ALA (12, 50, 100 mg/kg) (Somani et al., 2000). ...
Cisplatin (CDDP) has been widely used as a chemotherapeutic agent for solid tumors. The most common side effect of CDDP is nephrotoxicity, and many efforts have been made in the laboratory and the clinic to employ candidate adjuvants to CDDP to minimize this adverse influence. Many synthetic and herbal antioxidants as well as trace elements have been investigated for this purpose in recent years and a variety of positive and negative results have been yielded. However, no definitive supplement has so far been proposed to prevent CDDP-induced nephrotoxicity; however, this condition is gender related and the sex hormone estrogen may protect the kidney against CDDP damage. In this review, the results of research related to the effect of different synthetic and herbal antioxidants supplements are presented and discussed with suggestions included for future work.
... [143] LA can react with ROS and it also recycles Vitamin E and Vitamin C. [144] LA reduced mortality rate of rats after cerebral ischemia. [145] LA pretreatment reduced lesion volume in rat MCAO model when administered 30 min before the collusion. [145] A recent study further indicated that infusion of LA through the jugular vein immediately after reperfusion reduced lesion volume and promoted functional recovery in rat MCAO model. ...
... [145] LA pretreatment reduced lesion volume in rat MCAO model when administered 30 min before the collusion. [145] A recent study further indicated that infusion of LA through the jugular vein immediately after reperfusion reduced lesion volume and promoted functional recovery in rat MCAO model. [146] Tirilazad (U-74006F) is a synthetic lipid-soluble nonglucocorticoid. ...
Excessive oxygen and its chemical derivatives, namely reactive oxygen species (ROS), produce oxidative stress that has been known to lead to cell injury in ischemic stroke. ROS can damage macromolecules such as proteins and lipids and leads to cell autophagy, apoptosis, and necrosis to the cells. This review describes studies on the generation of ROS, its role in the pathogenesis of ischemic stroke, and recent development in therapeutic strategies in reducing oxidative stress after ischemic stroke.
... After removing duplicates, a total of 276 studies were screened based on title and abstract. Twelve studies were excluded due to their study design as in-vivo studies [18,19,20,21,22,23,24,25,26,27,28] and one cohort [29] was excluded. Six studies were further excluded as they were review articles [5,6,30,31,32,33]. ...
Background: Stroke, a major contributor to enduring disability on a global scale, demands inventive strategies for improving recuperation and alleviating concomitant neurological deficits. Several studies demonstrated improving effects of alpha-lipoic acid (ALA) on post-stroke patients. This study provided systematic review and meta-analysis of current literature concerning the potential impacts of ALA supplementation in individuals recovering from strokes.
Methods: Relevant studies were searched in the international databases, including PubMed, Scopus, Web of Science, up August 2023. The pooled results were calculated with the use of a random-effects model to assess the effects of ALA on post-stroke patients.
Results: The results revealed that the ALA supplementation was effective on fast plasma glucose levels (SMD= -1.57 mg/dl; 95% CI: -2.60, -0.54; P<0.001), high density lipoprotein levels (SMD= -5.04 mg/dl; 95% CI: -6.12, -3.97; P<0.001) and super oxide dismutase (SMD= 0.63 U/ml; 95% CI: 0.27, 1.00; P<0.05).
Conclusion: The findings of the current systematic review and meta-analysis reveal the advantageous effects of ALA on individuals recovering from a stroke.
... α-ketoglutarate dehydrogenase, and branched chain α-ketoacid dehydrogenase complex) [3]. In humans, due to the extensive tissue diffusion capacity, LA crosses the blood-brain barrier and is localized at cerebral cortex level [4]. The most important feature of this molecule is its powerful antioxidant activity. ...
... However, they failed later either in pre-clinical trial in adult primates or in clinical trials in humans, which suggest that supplementation of vitamins in food has little or no effect on the ischemic stroke associated pathways (Ascherio et al., 1999;Rabadi and Kristal, 2007). Use of NAC and LA have been shown to reduce cerebral infarct volume and improve neurological score in rats (Khan et al., 2004;Panigrahi et al., 1996). A clinical trial phase II with aim to assess the safety of NAC in combination with alteplase (rt-PA) at the acute phase of ischemic stroke is ongoing. ...
Oxidative stress has been established as a well-known pathological condition in several neurovascular diseases. It starts with increased production of highly oxidizing free-radicals (e.g. reactive oxygen species; ROS and reactive nitrogen species; RNS) and becomes too high for the endogenous antioxidant system to neutralize them, which results in a significantly disturbed balance between free-radicals and antioxidants levels and causes cellular damage. A number of studies have evidently shown that oxidative stress plays a critical role in activating multiple cell signaling pathways implicated in both progression as well as initiation of neurological diseases. Therefore, oxidative stress continues to remain a key therapeutic target for neurological diseases. This review discusses the mechanisms involved in reactive oxygen species (ROS) generation in the brain, oxidative stress, and pathogenesis of neurological disorders such as stroke and Alzheimer's disease (AD) and the scope of antioxidant therapies for these disorders.
... The ALA is derived from octanoic acid, which acts as a cofactor in several mitochondrial dehydrogenases [171]. As an active free-radical scavenger, ALA exhibits powerful antioxidative properties [172]. ...
Stroke is a fatal cerebral vascular disease with a high mortality rate and substantial economic and social costs. ROS production and neuroinflammation have been implicated in both hemorrhagic and ischemic stroke and have the most critical effects on subsequent brain injury. SIRT1, a member of the sirtuin family, plays a crucial role in modulating a wide range of physiological processes, including apoptosis, DNA repair, inflammatory response, and oxidative stress. Targeting SIRT1 to reduce ROS and neuroinflammation might represent an emerging therapeutic target for stroke. Therefore, we conducted the present review to summarize the mechanisms of SIRT1-mediated oxidative stress and neuroinflammation in stroke. In addition, we provide a comprehensive introduction to the effect of compounds and natural drugs on SIRT1 signaling related to oxidative stress and neuroinflammation in stroke. We believe that our work will be helpful to further understand the critical role of the SIRT1 signaling pathway and will provide novel therapeutic potential for stroke treatment.
... -L'acide lipoïque : Il réduit le volume de lésion de 38% à 24h (Choi et al., 2015) et la mortalité (Panigrahi et al., 1996). ll capte les radicaux HO•, 1 O2, NO, chélate les métaux de transition et recycle d'autres antioxydants tel que les vitamines E et C, et augmente les taux de glutathion (Packer et al., 1995). ...
Les accidents vasculaires cérébraux (AVC) constituent la 2ème cause de mortalité dans le monde et la 1ère chez les femmes en France. Pour les AVC ischémiques (AVCi), seules des stratégies de recanalisation pharmacologique ou mécanique ont été approuvées mais aucune stratégie protectrice n'est aujourd'hui disponible. Bien que le rôle délétère du stress oxydant ait été clairement établi dans les lésions neuronales et vasculaires à la suite d'une ischémie cérébrale (IC) dans les études précliniques, aucune stratégie anti-oxydante n'a démontré d'efficacité clinique à ce jour. Or, les nanoparticules d'oxyde de cérium (NPC) possèdent de multiples capacités antioxydantes (enzymatique et non enzymatique). Afin d'améliorer la biocompatibilité des NPC, la société Specific Polymers® a développé des copolymères de polyéthylène glycol (PEG)/ polyméthacrylate de méthyle/ phosphonate pour recouvrir leur surface. De plus, ces polymères peuvent être fonctionnalisés avec un peptide ciblant l'endothélium ce qui permettrait d'y concentrer l'effet antioxydant des NPC, afin de réduire la survenue d'hémorragies cérébrales, complications graves chez les patients victimes d'AVCi. L'objectif de cette thèse est d'évaluer l'impact du recouvrement des NPC sur leur potentiel thérapeutique dans l'IC. Les études ont été menées in vitro pour établir la toxicité, l'effet antioxydant et l'internalisation cellulaire des NPC et in vivo, pour examiner leur biodistribution et leur toxicité, ainsi que leur potentiel thérapeutique dans un modèle d'IC. Les études in vitro ont été effectuées sur des cellules endothéliales cérébrales murines de la lignée b.End3. Nous avons démontré que les NPC n'induisaient ni mortalité, ni perturbation de l'activité métabolique jusqu'à 100µg/ml. A 1000µg/mL, les NPC nues augmentent la mortalité, contrairement aux NPC PEGylées. Nous avons modélisé l'excitotoxicité survenant lors d'une IC et qui contribue au stress oxydant, grâce à un traitement des cellules par le glutamate. L'augmentation de la production d'espèces réactives de l'oxygène par les cellules b.End3 et l'oxydation des acides nucléiques dans ces conditions ont été réduites par les NPC, démontrant que leur recouvrement n'interfère pas avec leurs propriétés anti-oxydantes. La fonctionnalisation des NPC a permis le greffage d'un fluorophore pour suivre leur internalisation par cytométrie en flux et microscopie confocale. Nous avons ainsi mis en évidence que les NPC étaient rapidement internalisées dans les cellules b.End3. Des études de microscopie électronique ont ensuite montré que les NPC sont principalement localisées dans des endosomes périnucléaires. Enfin, nous avons réalisé le greffage sur les NPC d'un peptide ciblant une protéine d'adhésion vasculaire surexprimée lors de l'IC. La suite de ces études consistera à vérifier l'interaction spécifique de ces NPC avec la molécule d'adhésion. Les études in vivo ont permis d'établir la biodistribution des NPC chez des souris Swiss : des NPC sont retrouvées durant les premières heures suivant leur injection, avant leur élimination par voie rénale. L'histopathologie n'a révélé aucune toxicité des NPC sur le foie, les reins, la rate, les poumons et le cerveau de ces souris et aucune modification de leur numération sanguine n'a été observée. Les NPC ont ensuite été administrées dans un modèle murin d'IC, mais n'ont pas réduit le volume de la lésion dans nos conditions. En conclusion, le recouvrement des NPC par des polymères innovants a réduit leur toxicité sans altérer leurs capacités antioxydantes et leur internalisation dans des cellules endothéliales cérébrales. L'absence d'accumulation à long terme et de toxicité in vivo sont encourageantes quant à leur biocompatibilité. Bien que les NPC n'aient pas montré d'effet protecteur in vivo, celles ciblant l'endothélium pourraient réduire les lésions vasculaires et le risque hémorragique consécutif à une IC.
... It has been seen that after ischemic injury, instant α-LA treatment (20 mg/kg) had long-term (56 days) neuro-restorative effects against neural damage [52]. The neuroprotective effects of α-LA pretreatment for ischemic injury have been shown in several different experimental models of MCAO in rodents [51,[53][54][55][56]. ...
Lipoic acid (α-LA) (1,2-dithiolane3-pentanoic acid (C8H14O2S2) is also called thioctic acid with an oxidized (disulfide, LA) and a reduced (di-thiol: dihydro-lipoic acid, DHLA) form of LA. α-LA is a potent anti-oxidative agent that has a significant potential to treat neurodegenerative disorders. α-LA is both hydrophilic and hydrophobic in nature. It is widely distributed in plants and animals in cellular membranes and in the cytosol, which is responsible for LA’s action in both the cytosol and plasma membrane. A systematic literature review of Bentham, Scopus, PubMed, Medline, and EMBASE (Elsevier) databases was carried out to understand the Nature and mechanistic interventions of the α-Lipoic acid for central nervous system diseases. Moreover, α-LA readily crosses the blood-brain barrier, which is a significant factor for CNS activities. The mechanisms of α-LA reduction are highly tissue-specific. α-LA produces its neuroprotective effect by inhibiting reactive oxygen species formation and neuronal damage, modulating protein levels, and promoting neurotransmitters and anti-oxidant levels. Hence, the execution of α-LA as a therapeutic ingredient in the therapy of neurodegenerative disorders is promising. Finally, based on evidence, it can be concluded that α-LA can prevent diseases related to the nervous system.
... Lipoic acid (ALA, 1,2-dithiolane-3-pentanoic acid) recycles vitamin E and C [144] and is a free radical scavenger and a co-factor in the mitochondrial dehydrogenase complexes [145]. Pre-treatment with lipoic acid reduced infarct size [146] and improved functional recovery in animal models of stroke [147]. In a retrospective study of 172 thrombolysed acute ischemic stroke patients, 47 of which received alpha lipoic acid 600 mg/day, improved outcome was demonstrated both at 3 months and at one year [148]. ...
Recanalization therapy is increasingly used in the treatment of acute ischemic stroke. However, in about one third of these patients, recanalization is followed by ischemia/reperfusion injuries, and clinically to worsening of the neurological status. Much research has focused on unraveling the involved mechanisms in order to prevent or efficiently treat these injuries. What we know so far is that oxidative stress and mitochondrial dysfunction are significantly involved in the pathogenesis of ischemia/reperfusion injury. However, despite promising results obtained in experimental research, clinical studies trying to interfere with the oxidative pathways have mostly failed. The current article discusses the main mechanisms leading to ischemia/reperfusion injuries, such as mitochondrial dysfunction, excitotoxicity, and oxidative stress, and reviews the clinical trials with antioxidant molecules highlighting recent developments and future strategies.
... Non-phenolic metal chelators are thus potential geroprotective antiglycation agents. These include EDTA, which extends lifespan in C. elegans, and lipoic acid, which extends lifespan in rats [35,36]. ...
Geroprotectors slow down aging and promote healthy longevity in model animals. Although hundreds of compounds have been shown to extend the life of laboratory model organisms, clinical studies on potential geroprotectors are exceedingly rare, especially in healthy elders. This review aims to classify potential geroprotectors based on the mechanisms by which they influence aging. These pharmacological interventions can be classified into the following groups: those that prevent oxidation; proteostasis regulators; suppressors of genomic instability; epigenetic drugs; those that preserve mitochondrial function; inhibitors of aging-associated signaling pathways; hormetins; senolytics/senostatics; anti-inflammatory drugs; antifibrotic agents; neurotrophic factors; factors preventing the impairment of barrier function; immunomodulators; and prebiotics, metabiotics, and enterosorbents.
... 49 LA was also measured in the rat brain cortex, cerebellum, striatum, and hippocampus after intravenous and intraperitoneal administration. 50,51 Notably, a recent rat experiment found that the LA did not cross the BBB as easily as supposed after the correction for blood volume, which emphasized that the permeability of the BBB might be greatly influenced by cerebral blood flow. 52 ...
Lipoic acid (LA) is an endogenous antioxidant that exists widely in nature. Supplementation with LA is a promising approach to improve the outcomes of patients with multiple sclerosis (MS). This systematic review aimed to provide a comprehensive overview of both in vitro and in vivo studies describing the pharmacokinetics, efficacy, safety, and mechanism of LA in MS‐related experiments and clinical trials. A total of 516 records were identified by searching five databases, including PubMed, Web of Science, Embase, Scopus, and Cochrane Library. Overall, we included 20 studies reporting LA effects in cell and mouse models of MS and 12 studies reporting LA effects in patients with MS. Briefly, cell experiments revealed that LA protected neurons by inhibiting the expression of inflammatory mediators and activities of immune cells. Experimental autoimmune encephalomyelitis mouse experiments demonstrated that LA consistently reduced the number of infiltrating immune cells in the central nervous system and decreased the clinical disability scores. Patients with MS showed relatively stable Expanded Disability Status Scale scores and better walking performance with few adverse events after the oral administration of LA. Notably, heterogeneity of this evidence existed among modeling methods, LA usage, MS stage, and trial duration. In conclusion, this review provides evidence for the anti‐inflammatory and antioxidative effects of LA in both in vitro and in vivo experiments; therefore, patients with MS may benefit from LA administration. Whether LA can be a routine supplementary therapy warrants further study.
... 29 In previous studies, it has been demonstrated that ALA can improve clinical and pathological diseases. 30,31 Mitsui et al. reported that ALA has a neuroprotective effect on ischemia-reperfusion injury of distal sensory nerves via antioxidative properties. 18 Ranieri et al. clinically suggested usage of ALA in sciatic nerve related PNI. 32 Compatibly with these data, ALA has been suggested to have beneficial effects in neuropathic pain. ...
Peripheral nerve injury (PNI) is a major health problem that results in loss of motor and sensory functions. In treatment of PNI, various methods such as anastomosis, nerve grafts, nonneural tissue grafts, and nerve conduits are applied. In the present study, it was aimed to investigate the effects of Theranekron and Alpha-lipoic acid (ALA) combined treatment on nerve healing in experimental PNI by using histomorphometric, electron microscopic, immunohistochemical and molecular biological methods. Sixty-two Wistar rats were divided into six groups; the normal control group, sham operation group, experimental control group having a crush type injury with no treatment, Theranekron treatment group, ALA treatment group and Theranekron+ALA combined treatment group. Sciatic nerve tissue samples were obtained on days 1, 7 and 14 following injury in all groups. GAP-43 expression was upregulated in all PNI received groups compared to the control group. Krox-20 expression was downregulated in all groups that received PNI compared to the control group. While intensely positive TNF-α and IL-6 expressions were observed up to the 1st to the 14th day for the experimental control group, these expressions were seen as “weakly positive” in the treatment groups from the 1st day to the 14th day. The number of myelinated fibers was higher in the control and sham operation groups. Additionally, the number of myelinated nerve fibers increased in the combined treatment group. In conclusion, these findings suggest that combined therapy of Theranekron and ALA promotes structural recovery and it should be considered as an effective treatment protocol following PNI.
... LA в основному, але тимчасово накопичується в печінці, серці та скелетних м'язах, але трапляється і в інших тканинах. В обмеженій кількості досліджень було показано, що LA проникає через гематоенцефалічний бар'єр; внутрішньовенні дози 25 мг/кг маси тіла, що вводяться щурам, призводили до її накопичення в корі головного мозку протягом 60 хвилин після введення [24], а внутрішньовенні дози 100 мг/кг маси тіла -до її накопичення в корі головного мозку протягом 7-14 днів -як у молодих, так і у старих щурів спостерігалося накопичення LA в різних ділянках мозку [25]. Однак нещодавнє дослідження не виявило значних рівнів LA в головному мозку після перорального прийому [25]. ...
The paper presents an analysis of current literature data on the use of the R-enantiomer of α-lipoic acid as an antihypertensive treatment in patients with hypertension and metabolic syndrome. An analysis of the literature was carried out on its use as an antiinflammatory agent in inflammatory diseases. Currently, a very important aspect of researches is the possibility of using R-α-lipoic acid as a micronutrient and therapeutic agent for the treatment of diabetic polyneuropathy and neurodegenerative diseases, especially Alzheimer’s disease, carbohydrate metabolism disorders and metabolic syndrome. Lipoic acid has now become an important ingredient in multivitamin formulas, anti-aging supplements. R-α-lipoic acid is a metabolic antioxidant, its molecule contains a dithiolane ring in oxidized form, this ring has the ability to cleave with formation of dihydrolipoic acid. And since α-lipoic acid, a physiological form of thioctic acid, is a strong antioxidant that relieves the symptoms of diabetic neuropathy, the literature review analyzed data from various authors on the antioxidant effects of the R-enantiomer of α-lipoic acid and found that it had strong antioxidant effects, and its dose of 300 mg is bioequivalent to 600 mg of racemic α-lipoic acid. As presented in a sufficient number of analyzed sources, the biological role of lipoic acid is quite diverse. It is important to determine the exact causal relationship between lipoic acid and its immediate cellular targets. Lipoic acid can have a number of important and diverse physiological effects on the stimulation of neurohormonal function and, thus, indirectly affect multiple cellular signaling pathways in peripheral tissues.
... The development and administration of a co-drug, containing lipoic acid (LA) covalently linked to another compound, have been demonstrated to have a greater efficacy/potency compared to the administration of a mixture of the two drugs [11,12,13,14,15,16]. The antioxidant LA, is a known free radical scavenger [17,18], and many researchers have shown that in several different stroke models administration of lipoic acid on its own can be neuroprotective but only at relatively high doses [19,20,21,22,23,24]. Further, combining lipoic acid with other drugs has been shown to produce an additive or synergistic protective effect in several different animal models of pathology [25,26,27,28,29,30,31], when compared to the effect of either drug alone. ...
Background: Previously, our laboratory has provided evidence that pre-administration of the antioxidant, lipoic acid covalently bonded to various naturally occurring antioxidants, enhanced neuroprotective capacity compared to the administration of lipoic acid on its own. The naturally occurring compound scopoletin, a coumarin derivative, has been shown in various in vitro studies to have both antioxidant and anti-inflammatory mechanism of actions. To date, the effect of scopoletin on neuronal cell death in an in vivo model of ischemia or ischemia-reperfusion has not been investigated. Therefore, the present investigation was designed to determine if scopoletin on its own, or a co-drug consisting of lipoic acid and scopoletin covalent bond, named UPEI-400, would be capable of demonstrating a similar neuroprotective efficacy. Methods: Using a rodent model of stroke in male rats (anesthetized with Inactin®; 100 mg/kg, iv), the middle cerebral artery was permanently occluded for 6 hours (pMCAO), or in separate animals, occluded for 30 min followed by 5.5 hrs of reperfusion (ischemia/reperfusion; I/R). Results: Pre-administration of either scopoletin or UPEI-400 significantly decreased infarct volume in the I/R model (p<0.05), but not in the pMCAO model of stroke. However, UPEI-400 was ~1000 times more potent as compared to scopoletin on its own. The optimal dose of UPEI-400 was then injected during the occlusion and at several time points during reperfusion and significant neuroprotection was observed for up to 150 mins following the start of reperfusion (p<0.05). Conclusion: The data suggest that synthetic combination of scopoletin with lipoic acid (UPEI-400) is a more effective neuroprotectant that either compound on their own. Also, since UPEI-400 was only effective in a model of I/R, it is possible that it may act to enhance neuronal antioxidant capacity and/or upregulate anti-inflammatory pathways to prevent the neuronal cell death.
... Zbog svoji fizičko-hemijskih karakteristika, ALA vrlo lako prolazi krvno-moždanu barijeru, ispoljavajući na taj način, pozitivne antioksidativne efekte na nivou nervnih ćelija. Jedna od uloga ovog antioksidansa ogleda se sposobnosti da regeneriše depoe glutationa, koji su u obično smanjeni, kao posledica oksidativnog stresa, u toku šloga [43] i drugih cerebrovaskularnih događaja [44]. Rezultati novosprovedenih istraživanja potvrđuju pozitivnu ulogu ALA u terapiji i prevenciji Alchajmerove bolesti [45] i multiple skleroze [45] i šizofrenije [47]. ...
... LA is either distributed throughout the body, or filtered through the kidneys and excreted [43,47]. Whether or not LA crosses the blood brain barrier is debated with conflicting findings in studies of rats given oral LA [48,49]. Within cells, LA brakes down into metabolites or reduced to DHLA. ...
Oxidative stress (OS), when oxidative forces outweigh endogenous and nutritional antioxidant defenses, contributes to the pathophysiology of multiple sclerosis (MS). Evidence of OS is found during acute relapses, in active inflammatory lesions, and in chronic, longstanding plaques. OS results in both ongoing inflammation and neurodegeneration. Antioxidant therapies are a rational strategy for people with MS with all phenotypes and disease durations.
Purpose of review
To understand the function of OS in health and disease, to examine the contributions of OS to MS pathophysiology, and to review current evidence for the effects of selected antioxidant therapies in people with MS (PwMS) with a focus on lipoic acid (LA).
Recent findings
Studies of antioxidant interventions in both animal and in vivo models result in reductions in serum markers of OS and increases in levels and activity of antioxidant enzymes. Antioxidant trials in PwMS, while generally underpowered, detect short-term improvements in markers of OS and antioxidant defenses, and to a lesser extent, in clinical symptoms (fatigue, depression). The best evidence to date is a 2-year trial of LA in secondary progressive MS which demonstrated a significant reduction of whole-brain atrophy and trend toward improvement in walking speed.
Summary
Antioxidant therapy is a promising approach to treat MS across the spectrum and duration of disease. Rigorous and well-powered trials are needed to determine their therapeutic benefits.
... In this context, the use of α-lipoic acid (LA) and vitamin D3, which are well known to exert beneficial effects on the brain, can be hypothesized. Indeed, both LA and vitamin D3 are able to cross the blood-brain barrier (BBB) [25,26], and several studies have been performed to understand their functions within the ageing process of the brain [5,[27][28][29]. ...
Brain ageing is a complex multifactorial process characterized by gradual and continuous loss of neuronal functions. It is hypothesized that at the basis of brain ageing as well as age-related diseases, there is an impairment of the antioxidant defense system leading to an increase of oxidative stress. In this study, two different biological aspects involved in brain ageing and neurodegeneration have been investigated: oxidative stress and iron accumulation damage. In primary mouse astrocytes, the stimulation with 50 μM lipoic acid (LA) and 100 nM vitamin D (vitD) was first investigated in a time-course study to determine the dosages to be used in combination and then in a permeability test using an in vitro blood-brain barrier. In a second set of experiments, the role of oxidative stress was investigated pretreating astrocytes with 200 μM H2O2 for 30 min. The ability of vitD and LA alone and combined together to prevent or repair the damage caused by oxidative stress was investigated after 24 h of stimulation by the MTT test, mitochondrial membrane potential measurement, and Western blot analysis. To induce neurodegeneration, cells were pretreated with 300 μM catalytic iron for 6 days and then treated with vitD and LA alone and combined for additional 6 days to investigate the protection exerted by combination, analyzing viability, ROS production, iron concentration, and activation of intracellular pathways. In our study, the combination of LA and vitD showed beneficial effects on viability of astrocytes, since the substances are able to cross the brain barrier. In addition, combined LA and vitD attenuated the H2O2-induced apoptosis through the mitochondrial-mediated pathway. The combination was also able to counteract the adverse conditions caused by iron, preventing its accumulation. All these data support the hypothesis of the synergistic and cooperative activity exerted by LA and vitD in astrocytes indicating a possible new strategy to slow down ageing.
... The neuroprotective effect and the epigenetic activity displayed by these molecules, despite their low concentrations, indicate that a synergistic interaction between different bioactive components may occur in the PMM. Notably, the beneficial effect occurs at concentrations in the nanomolar range, compatible with the predicted brain levels of most of the bioactive components reachable at the recommended daily assumption dose of PMM [63][64][65][66][67][68][69][70][71]. Although the approach to studying PMM has the limitation of not discriminating the role of each specific compound separately, it offers the valuable advantage of evaluating the final result of multiple nutritional supplements when administered in combination. ...
Bioactive components, due in part to their epigenetic properties, are beneficial for preventing several human diseases including cerebrovascular pathologies. However, no clear demonstration supports the idea that these molecules still conserve their epigenetic effects when acting at very low concentrations reproducing the brain levels achieved after oral administration of a micronutrient supplement. In the present study, we used a cellular model of brain ischemia to investigate the neuroprotective and epigenetic activities of a commercially available micronutrient mixture (polyphenol-enriched micronutrient mixture, PMM) enriched in polyphenols ((-)-epigallocatechin-3-gallate, quercetin, resveratrol), α-lipoic acid, vitamins, amino acids and other micronutrients. Mimicking the suggested dietary supplementation, primary cultures of mouse cortical neurons were pre-treated with PMM and then subjected to oxygen glucose deprivation (OGD). Pre-treatment with PMM amounts to provide bioactive components in the medium in the nanomolar range potently prevented neuronal cell death. The protection was associated with the deacetylation of the lysin 310 (K310) on NF-κB/RelA as well as the deacetylation of H3 histones at the promoter of Bim, a pro-apoptotic target of ac-RelA(K310) in brain ischemia. Epigenetic regulators known to shape the acetylation state of ac-RelA(K310) moiety are the histone acetyl transferase CBP/p300 and the class III histone deacetylase sirtuin-1. In view of that evidence, the protection we here report unveils the efficacy of bioactive components endowed with either inhibitory activity on CBP/p300 or stimulating activity on the AMP-activated protein kinase–sirtuin 1 pathway. Our results support a potential synergistic effect of micronutrients in the PMM, suggesting that the intake of a polyphenol-based micronutrient mixture can reduce neuronal vulnerability to stressful conditions at concentrations compatible with the predicted brain levels reached by a single constituent after an oral dose of PMM.
... This would induce accumulation of dihydrolipoamide in the cell [47]. As dihydrolipoamide contains two free sulfhydryl groups, it has a strong antioxidation ability [39,[48][49][50][51]. Therefore, accumulation of dihydrolipoamide upon chronic inhibition of DLDH may give cells the ability to eliminate more reactive oxygen or nitrogen species under diabetic conditions. ...
Mitochondrial dihydrolipoamide dehydrogenase (DLDH) is a redox enzyme involved in decarboxylation of pyruvate to form acetyl-CoA during the cascade of glucose metabolism and mitochondrial adenine triphosphate (ATP) production. Depending on physiological or pathophysiological conditions, DLDH can either enhance or attenuate the production of reactive oxygen species (ROS) and reactive nitrogen species. Recent research in our laboratory has demonstrated that inhibition of DLDH induced antioxidative responses and could serve as a protective approach against oxidative stress in stroke injury. In this perspective article, we postulated that chronic inhibition of DLDH could also attenuate oxidative stress in type 2 diabetes. We discussed DLDH-involving mitochondrial metabolic pathways and metabolic intermediates that could accumulate upon DLDH inhibition and their corresponding roles in abrogating oxidative stress in diabetes. We also discussed a couple of DLDH inhibitors that could be tested in animal models of type 2 diabetes. It is our belief that DLDH inhibition could be a novel approach to fighting type 2 diabetes.
... Its structure contains hydroxyl and disulfide bonds, so it has both fat-soluble and water-soluble properties, and it easily crosses the BBB. The study found that, after 60 min of intravenous injection of LA in mice, the traces of LA were observed in the mouse cerebral cortex (Panigrahi et al., 1996). After a continuous injection over 7-14 days, the presence of LA was detected in multiple parts of the mouse brain (Arivazhagan et al., 2002). ...
As people age, iron deposits in different areas of the brain may impair normal cognitive function and behavior. Abnormal iron metabolism generates hydroxyl radicals through the Fenton reaction, triggers oxidative stress reactions, damages cell lipids, protein and DNA structure and function, and ultimately leads to cell death. There is an imbalance in iron homeostasis in Alzheimer’s disease (AD). Excessive iron contributes to the deposition of β-amyloid and the formation of neurofibrillary tangles, which in turn, promotes the development of AD. Therefore, iron-targeted therapeutic strategies have become a new direction. Iron chelators, such as desferoxamine, deferiprone, deferasirox, and clioquinol, have received a great deal of attention and have obtained good results in scientific experiments and some clinical trials. Given the limitations and side effects of the long-term application of traditional iron chelators, alpha-lipoic acid and lactoferrin, as self-synthesized naturally small molecules, have shown very intriguing biological activities in blocking Aβ-aggregation, tauopathy and neuronal damage. Despite a lack of evidence for any clinical benefits, the conjecture that therapeutic chelation, with a special focus on iron ions, is a valuable approach for treating AD remains widespread.
... Also, ALA pre-conditioning was capable of protecting simultaneous kidney-pancreas transplantation against I/R injury by reducing inflammatory markers [16]. Several previous studies also reported protective effects of ALA against brain I/R injury [17,18]. Although these previous studies stated the ALA protective effects against brain I/ R injury, few of them clearly clarified the mechanism of ALA treatments, which may restrict its potential application. ...
... Also, ALA pre-conditioning was capable of protecting simultaneous kidney-pancreas transplantation against I/R injury by reducing inflammatory markers [16]. Several previous studies also reported protective effects of ALA against brain I/R injury [17,18]. Although these previous studies stated the ALA protective effects against brain I/ R injury, few of them clearly clarified the mechanism of ALA treatments, which may restrict its potential application. ...
... Also, it is important to highlight that, ALA effect was also studied in cerebral IRI. As a result, Panigrahi et al. described a dramatically reduction in mortality rate in animals treated with ALA [39]. ...
Organ replacement is an option to mitigate irreversible organ damage. This procedure
has achieved a considerable degree of acceptance. However, several factors significantly limit its effectiveness. Among them, the initial inflammatory graft reaction due to ischemia-reperfusion injury (IRI) has a fundamental influence on the short and long term organ function. The reactive oxygen species (ROS) produced during the IRI actively participates in these adverse events. Therapeutic strategies that tend to limit the action of free radicals could result in beneficial effects in transplantation outcome. Accordingly, the anti-oxidant α-lipoic acid (ALA) have been proved to be protective in several animal experimental models and humans. In a clinical trial, ALA was found to decrease hepatic IRI after hepatic occlusion and resection. Furthermore, the treatment of cadaveric donor
and recipient with ALA had a protective effect in the short-term outcome in simultaneous kidney and pancreas transplanted patients. These studies support ALA as a drug to mitigate the damage caused by IRI and reinforce the knowledge about the deleterious consequences of ROS on graft injury in transplantation. The goal of this review is to overview the current knowledge about ROS in transplantation and the use of ALA to mitigate it.
... Biologically, ALA ameliorates oxidative stress in the mammalian brain, and this mechanism includes increasing the total GSH level (Panigrahi et al., 1996;Suh et al., 2004). Figure 4A, in accordance with our expectations, shows that ALA stimulated GSH accumulation in mouse brain. ...
The healthy human body contains small amounts of metabolic formaldehyde (FA) that mainly results from methanol oxidation by pectin methylesterase, which is active in a vegetable diet and in the gastrointestinal microbiome. With age, the ability to maintain a low level of FA decreases, which increases the risk of Alzheimer's disease and dementia. It has been shown that 1,2-dithiolane-3-pentanoic acid or alpha lipoic acid (ALA), a naturally occurring dithiol and antioxidant cofactor of mitochondrial α-ketoacid dehydrogenases, increases glutathione (GSH) content and FA metabolism by mitochondrial aldehyde dehydrogenase 2 (ALDH2) thus manifests a therapeutic potential beyond its antioxidant property. We suggested that ALA can contribute to a decrease in the FA content of mammals by acting on ALDH2 expression. To test this assumption, we administered ALA in mice in order to examine the effect on FA metabolism and collected blood samples for the measurement of FA. Our data revealed that ALA efficiently eliminated FA in mice. Without affecting the specific activity of FA-metabolizing enzymes (ADH1, ALDH2, and ADH5), ALA increased the GSH content in the brain and up-regulated the expression of the FA-metabolizing ALDH2 gene in the brain, particularly in the hippocampus, but did not impact its expression in the liver in vivo or in rat liver isolated from the rest of the body. After ALA administration in mice and in accordance with the increased content of brain ALDH2 mRNA, we detected increased ALDH2 activity in brain homogenates. We hypothesized that the beneficial effects of ALA on patients with Alzheimer's disease may be associated with accelerated ALDH2-mediated FA detoxification and clearance.
... For example, Shaafi and coworkers found that injection of 100 mg/kg subcutaneously 3 days prior to ischemia induction and 3 days after induction improved neurologic injury in rats. 108 Similarly, in another study by Panigrahi,109 LA administration in rats decreased reperfusion injury and increased survival rate dramatically in rats following cerebral ischemia. ...
Objectives: α-lipoic acid (ALA) is a natural antioxidant which acts as a cofactor of bioenergetic mitochondrial enzymes. Along with its mitochondrial action, ALA and its reduced form have many biological functions resulting in a wide variety of actions such as anti-inflammation and antioxidant protection, scavenging reactive oxygen species, regenerating other antioxidant agents, such as vitamins C and E, and cytosolic glutathione, chelating the transitional metal ions (e.g. iron and copper), and modulating the signal transduction of nuclear factor.
Methods: By selecting papers from PubMed, Science Direct, EBSCO, and databases, this review discusses the biochemical properties of LA, its mechanism of action, pharmacokinetics, and its possible therapeutic role in central nervous system diseases, such as Alzheimer’s disease, Parkinson’s disease, Multiple sclerosis, stroke, and spinal cord injury.
Results: ALA as an antioxidant and anti-inflammation agent has therapeutical effects on central nervous system diseases, especially multiple sclerosis and PD.
Discussion: ALA can be considered as a potentially useful treatment in central nervous disorders.
... [29] A fall in GSH (a non-protein sulfhydryl) during cerebral reperfusion injury is well reported and reduced level of T-SH reflects consumption of tissue thiols. [30] Sulfhydryl compounds are among the most important endogenous antioxidants. They have role in maintenance of cellular proteins and lipids in their functional states. ...
Restoration of blood flow to ischemic brain is linked with generation of reactive oxygen species. In Ayurveda, the medicinal properties of Tinospora cordifolia have been attributed to its anti-stress, antioxidant, neuroprotective, adaptogeneic and nootropic properties. The present study investigates the effect of ethanolic extract of T. cordifolia on acute cerebral ischemia-reperfusion in rats. Acute cerebral ischemia-reperfusion (30 min occlusion of bilateral common carotid arteries followed by 45 min reperfusion) in Charles Foster (C.F.) strain rats was produced following standard technique. Effect of Tinospora cordifolia on lipid peroxidation, superoxide dismutase (SOD) activity, ascorbic acid, cyclic AMP level and total tissue sulfhydryl (T-SH) group in for brain region in acute cerebral ischemia-reperfusion were evaluated. T. cordifolia pre-treatment (100 mg/kg p.o. for 7 days) attenuated the reperfusion induced biochemical alterations. The results suggest protective role of T. cordifolia in cerebral ischemia reperfusion injury.
... It is routinely used for the treatment of some pain disorders such as diabetic neuropathy (10). In addition, ALA was found to have a neuroprotective or therapeutic effects in some models mimicking various central nervous system disorders such as brain ischemia, endotoxic shock induced brain injury, subarachnoid hemorrhage, brain or spinal cord ischemia-reperfusion injury, and spinal cord injury (10,11,14,15,35,41). There were also some studies on the effect ALA on peripheral nervous system disorders. ...
Aim:
Background: Alpha lipoic acid (ALA) that is a strong antioxidant drug is tried for both protection and treatment of various diseases of central and peripheral nervous systems.
Material and methods:
Material and Methods: Protective effects of ALA on crush type peripheral nerve injury were evaluated. 28 Sprague-Dawley rats were divided into four groups: In Group 1, sciatic nerve was only explored. Sciatic nerve crush injury was performed after serum physiologic injection intraperitoneally in Group 2, and after ALA injection in Groups 3 and 4. In all subjects, Sciatic Functional Index (SFI) was calculated. All subjects were sacrificed 1 hour after injury in first three groups, and 48 hours after in Group 4. Nerve samples were taken. Superoxide dismutase, catalase and glutathione peroxidase activities were measured in nerve tissue.
Results:
Results: Administration of ALA before injury provided significantly better SFI values and higher levels of antioxidant enzymes than control group. These effects were significantly prominent 48 hours after injury.
Conclusion:
Conclusion: ALA that was given before crush type peripheral nerve injury provided to decrease damage of the nerve. Specific mechanisms of this effect must be clarified and must be shown that it is whether effective when it is given after injury or not.
... The ALA plays a fundamental role in antioxidative network [12,14]. A natural antioxidant, lipoic acid has been used in the treatment of diabetic neuropathy, ischemia-reperfusion injury and has been indicated to improve glucose metabolism [26][27][28]. The most important mechanism by which ALA directly stimulates insulin signaling pathways in skeletal muscle is increase in AMP-activated protein kinase (AMPK) activity and increase in fatty acid oxidation [25,29]. ...
Purpose:
Increased oxidative stress and impaired antioxidant defense are important mechanisms in the pathogenesis of diabetic myopathy. Since diabetes mellitus type 1 decreases muscle regeneration capacity the present study was designed to determine the influence of alpha-lipoic acid (ALA), a potent biological antioxidant, on the process of regeneration of diabetic rat skeletal muscles.
Methods:
40 Wistar rats were divided into three groups: control (n = 8), untreated diabetic group (n = 16) and ALA treated diabetic group (n = 16). The regeneration process was provoked in streptozotocin-induced diabetic rats in both slow (m.soleus, SOL) and fast (m.extensor digitorum longus, EDL) skeletal muscles by intramuscular injection of myotoxin bupivacaine. At intervals of 10 days and 4 weeks, muscle histochemical and morphometrical analysis (fiber cross areas and fiber type distribution) was performed.
Results:
Changes induced by diabetes are evident in redistribution of muscle fibers and in significant level of atrophy. After 4 weeks of diabetes, glycolytic muscle fibers are dominant in both slow and fast muscles. Muscle atrophy is present in all fiber types except in type I of slow skeletal muscle. Treatment with ALA reduce changes in the morphological properties caused by diabetes mellitus type 1 in slow and fast rat skeletal muscles during the process of regeneration.
Conclusion:
Treatment with lipoic acid during 4 weeks has shown effects on the redistribution of muscle fibers, and can prevent atrophy in slow and fast diabetic muscle.
... In addition to its function as an essential cofactor for mitochondrial bioenergetic enzymes in the production of energy, ALA is involved in a set of biochemical activities with potential pharmacotherapeutic value against a range of pathophysiological insults (9,31). Several studies have shown that exogenous ALA can readily cross the blood-brain barrier (32,33). Notably, the neuroprotective actions of ALA have been reported in in vivo and in vitro models of neurodegenerative diseases, including AD, macular degeneration and PD (17)(18)(19). ...
Oxidative stress appears to be a central event responsible for the degeneration of dopaminergic neurons in Parkinson's disease (PD). 1methyl4phenyl1,2,3,6tetrahydropyridine or its toxic metabolite 1methyl4phenylpyridinium (MPP+) are classical widelyused pharmacological and toxic agents to model PD; they cause the production of reactive oxygen species by inhibiting mitochondrial complex I, leading to DNA oxidative damage and subsequent neuronal death. Previous findings have suggested that proliferating cell nuclear antigen (PCNA), a critical regulatory protein for DNA repair, is involved in dopaminergic neuron damage in the MPP+ induced PD model. The naturally occurring dithiol compound, lipoic acid (ALA) has been reported to provide neuroprotection in in vitro models of PD. The molecular mechanism by which ALA reduces neuronal death in PD remains to be fully elucidated. The present study aimed to analyze the ability of ALA to protect neuronal PC12 cells from the toxicity induced by MPP+, and the molecular mechanism underlying these actions using MTT and lactate dehydrogenase cytotoxicity assays, Hoechst 33258 staining and western blot analysis. The results demonstrated that ALA efficiently increased the production of PCNA in MPP+treated PC12 cells. Accordingly, ALA treatment attenuated MPP+induced toxicity in the PC12 cells, and reduced cell apoptosis. The increase in the expression levels of PCNA by ALA in the MPP+treated PC12 cells appeared to be mediated by repression of the p53 protein, as the expression of p53 was increased by MPP+treatment and reduced by ALA. Taken together, these results indicated that ALA protected dopaminergic neurons against MPP+induced neurotoxicity through its ability to upregulate the DNA repair protein, PCNA, via the P53 pathway.
... Alpha-LA has been identified as a potent metabolic antioxidant that may serve as an ideal treatment for ischemic injury involving free radical processes. [35][36][37][38] The influence of R-(+)-alpha-LA, the naturally occurring enantiomer of LA, on pyruvate metabolism has been documented in primary cultured hepatocytes isolated from 24 h fasted rats. The results showed enhanced pyruvate oxidation and decreased gluconeogenesis. ...
Pyruvate dehydrogenase (PDH) complex is a mitochondrial matrix enzyme that serves a critical role in the conversion of anaerobic to aerobic cerebral energy. The regulatory complexity of PDH, coupled with its significant influence in brain metabolism, underscores its susceptibility to, and significance in, ischemia-reperfusion injury. Here, we evaluate proposed mechanisms of PDH-mediated neurodysfunction in stroke, including oxidative stress, altered regulatory enzymatic control, and loss of PDH activity. We also describe the neuroprotective influence of antioxidants, dichloroacetate, acetyl-L-carnitine, and combined therapy with ethanol and normobaric oxygen, explained in relation to PDH modulation. Our review highlights the significance of PDH impairment in stroke injury through an understanding of the mechanisms by which it is modulated, as well as an exploration of neuroprotective strategies available to limit its impairment.
... Early studies in both humans and experimental animal models have found that α-LA could decrease redox potential markers of oxidative stress following stroke or traumatic brain damage. 19 Administration of α-LA to rodents has been also demonstrated to reduce the damage that occurs after ischemia−reperfusion injuries in the central, 20 and peripheral nervous system. 21 α-LA has been found to prevent hydrogen peroxide-induced neuronal damage, 22 protect neurons toward neurotoxicity in Parkinson's 23 and reduce oxidative damage following stroke through enhancing the levels of superoxide dismutase type 2 (SOD 2 ). ...
α-Lipoic acid (α-LA), a natural thiol antioxidant and Tempol, a synthetic free radical scavenger are known to confer neuroprotection following ischemic insults both in in vivo and in vitro models. The aim of this study was to synthesize and characterize a conjugate of α-LA and Tempol linked by polyethylene glycol (PEG) in order to generate a more efficacious neuroprotectant molecule. AD3 (α-Tempol ester-ω-lipo ester PEG) was synthesized, purified and characterized by flash chromatography, reverse phase high pressure liquid chromatography and by 1H nuclear magnetic resonance, infrared spectroscopy and mass spectrometry. AD3 conferred neuroprotection in a PC12 pheochromocytoma cell line of dopaminergic origin, exposed to oxygen and glucose deprivation (OGD) insult measured by LDH release. AD3 exhibited EC50 at 10 µM and showed a 2-3 fold higher efficacy compared to the precursor moieties, indicating an intrinsic potent neuroprotective activity. AD3 attenuated by 25% the intracellular redox potential, by 54% lipid peroxidation and prevented phosphorylation of ERK, JNK and p38 by 57%, 22% and 21%, respectively. Cumulatively, these findings indicate that AD3 is a novel conjugate that confers neuroprotection by attenuation of MAPK phosphorylation and by modulation of the redox potential of the cells.
α-lipoic acid (LA) is an essential cofactor for mitochondrial dehydrogenases and is required for cell growth, metabolic fuel production, and antioxidant defense. In vitro, LA binds copper (Cu) with high affinity and as an endogenous membrane permeable metabolite could be advantageous in mitigating the consequences of Cu overload in human diseases. We tested this hypothesis in 3T3-L1 preadipocytes with inactivated Cu transporter Atp7a; these cells accumulate Cu and show morphologic changes and mitochondria impairment. Treatment with LA corrected the morphology of Atp7a-/- cells similar to the Cu chelator bathocuproinedisulfonate (BCS) and improved mitochondria function; however, the mechanisms of LA and BCS action were different. Unlike BCS, LA did not decrease intracellular Cu but instead increased selenium levels that were low in Atp7a-/- cells. Proteome analysis confirmed distinct cell responses to these compounds and identified upregulation of selenoproteins as the major effect of LA on preadipocytes. Upregulation of selenoproteins was associated with an improved GSH:GSSG ratio in cellular compartments, which was lowered by elevated Cu, and reversal of protein oxidation. Thus, LA diminishes toxic effects of elevated Cu by improving cellular redox environment. We also show that selenium levels are decreased in tissues of a Wilson disease animal model, especially in the liver, making LA an attractive candidate for supplemental treatment of this disease.
Oxidative stress plays a key role in the pathogenesis of neuronal injury, including ischemia. Ras-related nuclear protein (RAN), a member of the Ras superfamily, involves in a variety of biological roles, such as cell division, proliferation, and signal transduction. Although RAN reveals antioxidant effect, its precise neuroprotective mechanisms are still unclear. Therefore, we investigated the effects of RAN on HT-22 cell which were exposed to H2O2-induced oxidative stress and ischemia animal model by using the cell permeable Tat-RAN fusion protein. We showed that Tat-RAN transduced into HT-22 cells, and markedly inhibited cell death, DNA fragmentation, and reactive oxygen species (ROS) generation under oxidative stress. This fusion protein also controlled cellular signaling pathways, including mitogen-activated protein kinases (MAPKs), NF-κB, and apoptosis (Caspase-3, p53, Bax and Bcl-2). In the cerebral forebrain ischemia animal model, Tat-RAN significantly inhibited both neuronal cell death, and astrocyte and microglia activation. These results indicate that RAN significantly protects against hippocampal neuronal cell death, suggesting Tat-RAN will help to develop the therapies for neuronal brain diseases including ischemic injury.
Mitochondria serve vital roles critical for overall cellular function outside of energy transduction. Thus, mitochondrial decay is postulated to be a key factor in aging and in age-related diseases. Mitochondria may be targets of their own decay through oxidative damage. However, treating animals with antioxidants has been met with only limited success in rejuvenating mitochondrial function or in increasing lifespan. A host of nutritional strategies outside of using traditional antioxidants have been devised to promote mitochondrial function. Dietary compounds are under study that induce gene expression, enhance mitochondrial biogenesis, and mitophagy, or replenish key metabolites that decline with age. Moreover, redox-active compounds may now be targeted to mitochondria which improve their effectiveness. Herein we review the evidence that representative dietary effectors modulate mitochondrial function by stimulating their renewal or reversing the age-related loss of key metabolites. While in vitro evidence continues to accumulate that many of these compounds benefit mitochondrial function and/or prevent their decay, the results using animal models and, in some instances human clinical trials, are more mixed and sometimes even contraindicated. Thus, further research on optimal dosage and age of intervention are warranted before recommending potential mitochondrial rejuvenating compounds for human use.
Ischemia-reperfusion (I/R) injury often occurred in some pathologies and surgeries. I/R injury not only harmed to physiological functions of corresponding organ and tissue but also induced multiple tissue or organ dysfunctions (even these in distant locations). Although the reperfusion of blood attenuated I/R injury to a certain degree, the risk of secondary damages was difficult to be controlled and it even caused failures of these tissues and organs. Lipoic acid (LA), as an endogenous active substance and a functional agent in food, owns better safety and effects in our body (e.g., enhancing antioxidant activity, improving cognition and dementia, controlling weight, and preventing multiple sclerosis, diabetes complication, and cancer). The literature searching was conducted in PubMed, Embase, Cochrane Library, Web of Science, and SCOPUS from inception to 20 May 2021. It had showed that endogenous LA was exhausted in the process of I/R, which further aggravated I/R injury. Thus, supplements with LA timely (especially pretreatments) may be the prospective way to prevent I/R injury. Recently, studies had demonstrated that LA supplements significantly attenuated I/R injuries of many organs, though clinic investigations were short at present. Hence, it was urgent to summarize these progresses about the effects of LA on different I/R organs as well as the potential mechanisms, which would enlighten further investigations and prepare for clinic applications in the future.
Domoic acid (DA) is a potent neurotoxin produced by certain marine algae that can cause neurologic and cardiac dysfunction by activating glutamate receptors. Glutamate receptor overexcitation results in continuous cellular activation, oxidative damage, and cell death. DA toxicosis causes disorientation and seizures, and antiseizure medications are the primary treatment. Alpha lipoic acid (ALA), a powerful antioxidant and glutathione precursor widely used in humans and dogs, can cross the blood-brain barrier to provide antioxidant availability to brain tissue. Hundreds of stranded California sea lions (CSL; Zalophus californianus) are diagnosed annually with DA toxicosis and thus are an appropriate animal in which to establish ALA dosing recommendations for treatment. The objective of this study was to determine the population pharmacokinetics of a single 10- or 20-mg/kg dose of ALA administered subcutaneously into the interscapular region to healthy rehabilitated CSL. Blood was collected at two time points between 15 min and 24 h after administration. Serum ALA concentrations were measured by liquid chromatography-mass spectrometry, and parameters were evaluated using a nonlinear mixed effects model. ALA was rapidly absorbed for each dose, peaking within 20 to 30 minutes, and t1/2 of 40 and 32 min (10 and 20 mg/kg, respectively), followed by an initial steep distribution phase and prolonged elimination phase. Peak concentration (CMAX) was 1,243 ng/ml (10-mg/ml dose) and 5,010 ng/ml (20-mg/ml dose). Serum from 13 CSLd with DA toxicosis treated with 10 mg/kg ALA for 1 to 9 d had measurable levels, and ALA was also measurable in cerebrospinal fluid from two treated CSLs. Therapeutic effects are noted with a CMAX of 4,000 to 5,000 ng/ml in humans; thus in CSLs, 20 mg/kg administered subcutaneously once daily may be sufficient to achieve a therapeutic level in this species. Determination of efficacy and optimal dosing interval and duration require additional investigation.
Cellular redox homeostasis is predominantly controlled by the ratio of thiols and disulfides, and reversible thiol-disulfide exchange reactions are fundamental of the biological redox regulation. However, due to the dynamic exchanges of thiols and disulfides, the detection, especially the in situ detection, of protein disulfides (PDS) is challenging. We employ the strategy, i.e., the increase of emission upon an environment-sensitive dye binding to proteins, to design PDS probes and discover a two-photon probe PDSTP590 (S6) that selectively recognizes PDS in live organisms. With the aid of the probe, we further disclose the elevation of PDS in brains of the mouse stroke model.
Both aging and age‐associated neurodegenerative diseases are associated with various degrees of behavioral impairments, and among the prime candidates responsible for producing the neuronal changes mediating these behavioral deficits appear to be free radicals and the oxidative stress they generate. Therefore, there have been a number of studies which have examined the putative positive benefits of antioxidants in altering, reversing, or forestalling these neuronal/behavioral decrements, with varying degrees of success. Additional experiments have examined the effects of diets rich in fruits and vegetables or herbal extracts in reducing certain types of cancer and cardiovascular diseases, and evidence emerging from such experiments suggests that these kinds of dietary modifications may be beneficial in altering neuronal/behavioral deficits in aging, as well. These kinds of diets are particularly rich in antioxidants such as vitamins A, C, E, and bioflavonoids (such as flavones, tannins, and anthocyanins), and thus, there may be synergistic effects among them. The present paper will review studies concerning the influence of dietary and synthetic antioxidants on normal, pathological age‐related, and reactive oxygen species‐induced behavioral changes in human and animal subjects. The antioxidants reviewed are vitamin E, α‐lipoic acid, and the phytochemicals contained in herbals, fruits and vegetables.
Neurodegenerative diseases are irreversible conditions that result in progressive degeneration and death of nerve cells. Although the underlying mechanisms may vary, oxidative stress is considered to be one of the major causes of neuronal loss. Importantly, there are still no comprehensive treatments to completely cure these diseases. Therefore, protecting neurons from oxidative damage may be the most effective therapeutic strategy. Here we report a neuroprotective effects of a novel hybrid compound (dlx-23), obtained by conjugating alpha-lipoic acid (ALA), a natural antioxidant agent, and 3-n-butylphthalide (NBP), a clinical anti-ischemic drug. Dlx-23 protected against neuronal death induced by both H2O2 induced oxidative stress in Cath.-a-differentiated (CAD), and 6-OHDA, a toxin model of Parkinson’s disease (PD) in SHSY-5Y cells. These activities proved to be more potent than the parent compound (ALA) alone. Dlx-23 scavenged free radicals, increased glutathione levels, and prevented mitochondria damage. In addition, live imaging of primary cortical neurons demonstrated that dlx-23 protected against neuronal growth cones damage induced by H2O2. Taken together these results suggest that dlx-23 has substantial potential to be further developed into a novel neuroprotective agent against oxidative damage and toxin induced neurodegeneration.
Background:
Exposure to arsenic has been reported to affect the nervous system in a number of ways. Various epidemiological studies suggest cognitive impairment in subjects following exposure to environmental arsenic. The goal of the present study was to determine if supplementation of exogenous α-lipoic acid (ALA) could ameliorate sodium arsenite (NaAsO2) induced adverse effects on learning and memory and synaptic connectivity in rat hippocampus.
Methods:
Accordingly, NaAsO2 alone (1.5/2.0 mg/kg bw) or NaAsO2 along with ALA (70 mg/kg bw) was administered by intraperitoneal (i.p.) route from postnatal day (PND) 4-17 to Wistar rat pups (experimental groups) and the Control groups received either distilled water or no treatment at all. After carrying out Elevated Plus Maze (EPM) and Morris Water Maze (MWM) test, the fresh brain tissues were collected on PND 18 and processed for Golgi Cox staining.
Results:
Observations of MWM test revealed impaired learning and memory in iAs alone treated animals as against those co-exposed to iAs and ALA. In Golgi stained hippocampal sections of iAs alone treated animals, decreased dendritic arborization and reduced number of spines in pyramidal neurons (CA1) and granule cells (DG) was observed whereas neuronal morphology was preserved in the controls and ALA supplemented groups CONCLUSIONS: These observations are suggestive of beneficial effects of ALA on iAs induced effects on learning and memory as well as on hippocampal neuronal morphology.
Aim:
In this study, we aimed to investigate the protective effect of krill oil (KO) against ischemia-reperfusion (I/R) injury on rat ovary.
Methods:
This study was conducted with 32 Wistar Albino rats. Rats were divided into four groups, with eight rats in each group-as follows: Sham group, I/R group, I/R + low dose KO group (50 mg) and I/R + high dose KO group (500 mg). The histopathological and follicle counts were performed on the right ovary. The total antioxidant status, total oxidant status and oxidative stress index were evaluated on the left ovary. And also serum N-thiol level, serum T-thiol level, serum disulfide (SDS) level, serum disulfide/N-thiol and serum disulfide/T-thiol ratios were evaluated too.
Results:
A statistically significant difference was determined between the I/R group and all the other groups for all parameters. There was significant difference between KO groups and the Sham group for the parameters of serum N-thiol, serum T-thiol, SDS, serum disulfide/N-thiol and serum disulfide/T-thiol. SDS, total oxidant status and oxidative stress index were determined to be the highest in the I/R group and the lowest in the low dose KO group. The total antioxidant status values were found to be the highest in the high dose KO group and the lowest in the I/R group. Follicle counts and histological injury scores showed no significant difference between Sham and KO groups.
Conclusion:
This study demonstrated that KO has beneficial effects on decreasing the injury after I/R on rat ovary.
In der hier vorliegenden Arbeit konnte zum ersten Mal eine Reduktion der Aktivität des PDHC in der Frühphase nach einer SAB im Tierversuch in der Ratte gezeigt werden. Da der PDHC bei der effizienten aeroben Energiegewinnung durch die Einschleusung von Pyruvat in den Zitratzyklus, den entscheidenden Enzymkomplex darstellt, könnte eine Aktivitätsminderung des PDHC ein möglicher Faktor für einen sekundären Hirnschaden und neuronalen Zellschaden nach einer SAB sein. Dass der lange als entscheidend für das schlechte Outcome von SAB-Patienten verantwortlich gemachte verzögerte Vasospasmus nach einer SAB alleine nicht für den sekundären Hirnschaden im Rahmen dieser Erkrankung herhalten kann, wird dadurch unterstrichen, dass der Vasospasmus mittlerweile gut therapiert werden kann, diese Therapie das Outcome der SAB aber nicht signifikant verbessert hat. Eine metabolische Komponente des sekundären Hirnschadens, möglicherweise kombiniert mit einer arteriellen Vasokonstriktion, sollte nach den Ergebnissen dieser Studie durchaus in Betracht gezogen werden. Die Ergebnisse stellen den PDHC als mögliches Ziel für eine neuroprotektive Therapie der SAB heraus. Eine suffiziente Stimulierung des PDHC oder ein Schutz des Enzymkomplexes vor Inaktivierung oder Schädigung könnte in der Frühphase der SAB protektiv wirken. Die Ergebnisse der hier vorliegenden Arbeit sind somit von klinischer Relevanz und sollten Anlass zu weiteren, auch klinischen Studien im Bereich der Funktionsbeeinflus-sung des PDHC geben. Weiterhin scheint eine Untersuchung weiterer metabolischer Schritte gewinnbringend, um weitere mögliche Angriffspunkte einer gezielten Therapie zu identifizieren.
High-fat diet (HFD)-induced obesity is accompanied by insulin resistance and compromised brain synaptic plasticity through the impairment of insulin-sensitive pathways regulating neuronal survival, learning, and memory. Lipoic acid is known to modulate the redox status of the cell and has insulin mimetic effects. This study was aimed at determining the effects of dietary administration of lipoic acid on a HFD-induced obesity model in terms of (a) insulin signaling, (b) brain glucose uptake and neuronal- and astrocytic metabolism, and (c) synaptic plasticity. 3-Month old C57BL/6J mice were divided into 4 groups exposed to their respective treatments for 9 weeks: (1) normal diet, (2) normal diet plus lipoic acid, (3) HFD, and (4) HFD plus lipoic acid. HFD resulted in higher body weight, development of insulin resistance, lower brain glucose uptake and glucose transporters, alterations in glycolytic and acetate metabolism in neurons and astrocytes, and ultimately synaptic plasticity loss evident by a decreased long-term potentiation (LTP). Lipoic acid treatment in mice on HFD prevented several HFD-induced metabolic changes and preserved synaptic plasticity. The metabolic and physiological changes in HFD-fed mice, including insulin resistance, brain glucose uptake and metabolism, and synaptic function, could be preserved by the insulin-like effect of lipoic acid.
Previously, our laboratory provided evidence that lipoic acid (LA) covalently bonded to various antioxidants, resulted in enhanced neuroprotection compared to LA on its own. The naturally occurring compound scopoletin, a coumarin derivative, has been shown in various in vitro studies to have both antioxidant and anti-inflammatory mechanism of actions. The present investigation was designed to determine if scopoletin on its own, or a co-drug consisting of LA and scopoletin covalently bonded together, named UPEI-400, would be capable of demonstrating a similar neuroprotective efficacy. Using a rat stroke model, male rats were anesthetized (Inactin®; 100 mg/kg, iv), the middle cerebral artery was permanently occluded for 6 h (pMCAO), or in separate animals, occluded for 30 min followed by 5.5 h of reperfusion (ischemia/reperfusion; I/R). Pre-administration of either scopoletin or UPEI-400 significantly decreased infarct volume in the I/R model (p < 0.05), but not in the pMCAO model of stroke. UPEI-400 was ∼1000 times more potent compared to scopoletin alone. Since UPEI-400 was only effective in a model of I/R, it is possible that it may act to enhance neuronal antioxidant capacity and/or upregulate anti-inflammatory pathways to prevent the neuronal cell death.
Adult T cell leukemia-derived factor (ADF) is a human homologue of thioredoxin (TRX) with many biological functions and is induced by various stimuli and stress. In the central nervous system (CNS), expression of ADF/TRX occurs in glial cells during ischemia and reperfusion. We showed that ADF/TRX was actively released from U251 astrocytoma cells upon exposure to a low concentration of H2O2. The addition of conditioned medium from H2O2-stimulated U251 cells or recombinant ADF (rADF) to the culture medium promoted the survival of neurons from embryonic mouse cortex and striatum, but the addition of mutant ADF (mADF), which has no reducing activity, did not. In addition to rADF, incubation with two other thiol compounds, 2-mercaptoethanol (2-ME) andN-acetyl-l-cysteine (NAC), also increased the neuronal cell survival rate. In contrast,l-buthionine-(S,R)-sulfoximine (BSO), which inhibited the synthesis of glutathione (GSH), decreased the neuronal cell survival rate. Intracellular GSH was increased by incubation with rADF for 24 h, as it is with 2-ME and NAC. Redox active molecules such as thiol compounds may be survival factors for central neurons in vitro, and this capacity may be supplied by endogenous molecules, such as ADF/TRX and glutathione, under certain pathologic conditions in vivo.
It has been shown in vitro that dihydrolipoate (DL-6,8-dithioloctanoic acid) has antioxidant activity against microsomal lipid peroxidation. We tested dihydrolipoate for its neuroprotective activity using models of hypoxic and excitotoxic neuronal damage in vitro and rodent models of cerebral ischemia in vivo. In vitro, neuronal damage was induced in primary neuronal cultures derived form 7-day-old chick embryo telencephalon by adding either 1 mM cyanide or 1 mM glutamate to the cultures. Cyanide-exposed and dihydrolipoate-treated (10(-9)-10(-7) M) cultures showed an increased protein and ATP content compared with controls. The glutamate-exposed cultures treated with dihydrolipoate (10(-7)-10(-5) M) showed a decreased number of damaged neurons. In vivo, dihydrolipoate treatment (50 and 100 mg/kg) reduced brain infarction after permanent middle cerebral artery occlusion in mice and rats. Dihydrolipoate treatment (50 and 100 mg/kg) could not ameliorate neuronal damage in the rat hippocampus or cortex caused by 10 min of forebrain ischemia. A comparable neuroprotection was obtained by using dimethylthiourea, both in vitro (10(-7) and 10(-6) M) and at a dose of 750 mg/kg in the focal ischemia models. Lipoate, the oxidized form of dihydrolipoate, failed to reduce neuronal injury in any model tested. We conclude that dihydrolipoate, similarly to dimethylthiourea, is able to protect neurons against ischemic damage by diminishing the accumulation of reactive oxygen species within the cerebral tissue.
Free radicals have been shown to play an important role in ischemia-reperfusion injury in several organ systems; however, the role of free radicals in central nervous system ischemia has been less well studied. Many potential free radical-generating systems exist. The primary products of these reactions, superoxide and hydrogen peroxide, may combine to produce hydroxyl radicals. Of the many potential sources of free radical generation, the enzyme xanthine oxidase has been shown to be important in ischemia in noncerebral tissue. We investigated the effect of the hydroxyl radical scavenger dimethylthiourea and the xanthine oxidase inhibitor allopurinol on infarct volume in a model of continuous partial ischemia. Male Sprague-Dawley rats were treated with dimethylthiourea or allopurinol before middle cerebral artery occlusion. Infarct volume was measured by triphenyltetrazolium chloride staining of brains removed 3 or 24 hours after occlusion. Stroke volume was reduced by 30% after dimethylthiourea treatment and by 32-35% after allopurinol treatment. At 24 hours after stroke, cortical tissue was more effectively protected than caudate tissue with both agents. Pretreatment with dimethylthiourea and allopurinol also significantly reduced cerebral edema formation and improved blood-brain barrier function as measured by fluorescein uptake. Our results imply that hydroxyl radicals are important in tissue injury secondary to partial cerebral ischemia and that xanthine oxidase may be the primary source of these radicals.
Superoxide dismutase and catalase enzymatically scavenge superoxide and hydrogen peroxide, respectively. Conjugation of polyethylene glycol to superoxide dismutase (PEG-SOD) or catalase (PEG-CAT) prolongs the circulatory half-life of the native enzymes and enhances their intracellular access. We studied the protective effect of these free radical scavengers on ischemic brain injury using a rat model of focal cerebral ischemia, which is suitable for therapeutic trials. Intravenous administration of PEG-SOD (10,000 U/kg) and PEG-CAT (10,000 U/kg) before ischemia reduced the infarct volume (treatment, 139 +/- 9 mm3, means +/- SE, N = 38; placebo, 182 +/- 8 mm3, n = 37, P less than 0.002). This finding supports the concept that superoxide and hydrogen peroxide contribute to brain injury following focal cerebral ischemia.
ABSTRACT— A model is described in which transient ischemia is induced in rats anaesthetized with N2O:O2 (70:30) by bilateral carotid artery clamping combined with a lowering of mean arterial blood pressure to 50 mm Hg, the latter being achieved by bleeding, or by bleeding supplemented with administration of trimetaphan or phentolamine. By the use of intubation, muscle paralysis with suxamethonium chloride, and insertion of tail arterial and venous catheters, it was possible to induce reversible ischemia for long-term recovery studies.Autoradiographic measurements of local CBF showed that the procedure reduced CBF in neocortical areas, hippocampus, and caudoputamen to near-zero values, flow rates in a number of subcortical areas being variable. Administration of trimethaphane or phentolamine did not affect ischemic and postischemic flow rates, nor did they alter recovery of EEG and sensory-evoked responses, but trimetaphan blunted the changes in plasma concentrations of adrenaline and noradrenaline.Recovery experiments showed that 10 min of ischemia gave rise to clear signs of permanent brain damage, with a small number of animals developing postischemic seizures that led to the death of the animals in status epilepticus. After 15 min of ischemia, such alterations were more pronounced, and the majority of animals died. It is concluded that the short revival times noted are explained by the fact that the model induces near-complete ischemia, and that recovery following forebrain ischemia is critically dependent on residual flow rates during the period of ischemia.
Lipoic acid has been reported recently to be an effective antioxidant in biological systems. It may act in vivo through reduction to its dithiol form, dihydrolipoic acid. Using a dual Hg/Au electrode, and HPLC with electrochemical detection, a method was developed which allowed simultaneous measurement of lipoic acid and dihydrolipoic acid, at nanomolar levels. (RS)-α-Lipoic acid was added to human cells in tissue culture (Jurkat T-lymphocytes and primary neonatal diploid fibroblasts). Lipoic acid was converted rapidly by the cells to dihydrolipoic acid, which accumulated in the cell pellet. Monitored over a 2-hr interval, dihydrolipoic acid was released, and several-fold more dihydrolipoic acid could be found in the medium than in the pellet.
This article provides an overview of how peroxidation of unsaturated lipids takes place and how it can be measured. Several different aspects of free-radical-mediated lipid peroxidation are discussed, including: (a) the catalytic role of chelated iron and other redox metal ions; (b) induction by reducing agents such as superoxide, ascorbate, and xenobiotic free radicals; (c) suppression by antioxidant chemicals and enzymes; and (d) how peroxidation that depends on pre-existing hydroperoxides (lipid hydroperoxide-dependent initiation of lipid peroxidation) can be distinguished from that which does not (lipid hydroperoxide-independent initiation of lipid peroxidation). Attention is also given to non-radical, singlet oxygen-driven peroxidation and how this can be resolved from radical-driven processes.
t-Butyl hydroperoxide was utilized to alter the thiol homeostasis in rat brain mitochondria. Following exposure to t-butyl hydroperoxide (50-500 microM), intramitochondrial GSH content decreased rapidly and irreversibly with a major portion of the depleted GSH being accounted for as protein-SS-Glutathione mixed disulfide. Formation of GSSG was not observed nor was efflux of GSSG or GSH from the mitochondria detected in the incubation medium. The loss of intramitochondrial GSH was accompanied by loss of protein thiols. Unlike liver mitochondria, which can reverse t-butyl hydroperoxide induced formation of GSSG, addition of 50 microM t-butyl hydroperoxide resulted in irreversible loss; indicating greater susceptibility of brain mitochondria to oxidative stress than liver mitochondria.
Oxygen free radicals generated during reoxygenation after cardiac arrest may impair recovery of cerebral blood flow and function. In a randomized study in vivo, we tested the following anti-free radical combination therapy administered at the beginning of cardiopulmonary resuscitation after apnea-induced cardiac arrest of 7 minutes: 1) ventilation with 100% nitrogen for 30 seconds to allow the delivery of therapy before oxygen, 2) 10 mg/kg i.a. superoxide dismutase followed by 10 mg/kg i.v. over 1 hour to scavenge the superoxide anion radical, and 3) 20 mg/kg i.v. deferoxamine over 1 hour to prevent membrane lipid peroxidation. We evaluated the effects of this combined treatment on the recovery of cardiovascular variables, cerebral blood flow and oxygen consumption, and somatosensory evoked potentials in 20 dogs 6 hours after resuscitation. Compared with standard treatment (n = 10), the combined treatment (n = 10) did not affect cardiovascular variables, significantly mitigated cerebral blood flow changes after cardiac arrest, and enhanced recovery of somatosensory evoked potentials. We conclude that oxygen free radicals play a role in the pathogenesis of the arrest-related derangements of cerebral blood flow and function that are effectively reduced by this combined treatment; we recommend evaluation of its components in outcome studies.
Microvessel segments were isolated from rat brain and used for studies of hypoxanthine transport and metabolism. Compared to an homogenate of cerebral cortex, the isolated microvessels were 3.7-fold enriched in xanthine oxidase. Incubation of the isolated microvessels with labeled hypoxanthine resulted in its rapid uptake followed by the slower accumulation of hypoxanthine metabolites including xanthine and uric acid. The intracellular accumulation of these metabolites was inhibited by the xanthine oxidase inhibitor allopurinol. Hypoxanthine transport into isolated capillaries was inhibited by adenine but not by representative pyrimidines or nucleosides. Similar results were obtained when blood to brain transport of hypoxanthine in vivo was measured using the intracarotid bolus injection technique. Thus, hypoxanthine is transported into brain capillaries by a transport system shared with adenine. Once inside the cell, hypoxanthine can be metabolized to xanthine and uric acid by xanthine oxidase. Since this reaction leads to the release of oxygen radicals, it is suggested that brain capillaries may be susceptible to free radical mediated damage. This would be most likely to occur in conditions where the brain hypoxanthine concentration is increased as following ischemia.
A method for the analysis of nanogram quantities of glutathione has been developed which is based on the catalytic action of GSH or GSSG in the reduction of Ellman reagent (DTNB) by a mixture of TPNH and yeast glutathione reductase. Unlike previous methods of analysis the procedure described here effectively measures the total glutathione (GSH + GSSG) content of unknown mixtures and is not subject to appreciable interference by the presence of other thiol components. It is suggested that the catalytic action of glutathione in this system resides in the continual enzymic regeneration of GSH, present initially or formed enzymically from GSSG, following its interaction with the sulfhydryl reagent.The sensitivity of the method is such as to permit the determination of total glutathione in extracellular tissue fluids such as plasma, saliva, and urine normally containing very low levels of this material, essentially without pretreatment of the sample. The same is true for glutathione determinations of whole blood, in which the preliminary procedure is confined to the preparation of a 1:100 hemolyzate from as little as 10 μl of sample.Following published procedures, the pretreatment of tissue extracts with NEM to form an enzymically inactive complex with free GSH allowed the determination of the low levels of oxidized glutathione normally present therein. The use of the foregoing analytical method in the determination of total and oxidized glutathione contents of rat blood, kidney, and liver gave values in good agreement with those obtained by previous investigators.
Rats were implanted with 0.3-mm-diameter dialysis tubing through the hippocampus and subsequently perfused with Ringer's solution at a flow rate of 2 microliter/min. Samples of the perfusate representing the extracellular fluid were collected over 5-min periods and subsequently analyzed for contents of the amino acids glutamate, aspartate, glutamine, taurine, alanine, and serine. Samples were collected before, during, and after a 10-min period of transient complete cerebral ischemia. The extracellular contents of glutamate and aspartate were increased, respectively, eight- and threefold during the ischemic period; the taurine concentration also was increased 2.6-fold. During the same period the extracellular content of glutamine was significantly decreased (to 68% of the control value), whereas the concentrations of alanine and serine did not change significantly during the ischemic period. The concentrations of gamma-aminobutyric acid (GABA) were too low to be measured reliably. It is suggested that the large increase in the content of extracellular glutamate and aspartate in the hippocampus induced by the ischemia may be one of the causal factors in the damage to certain neurons observed after ischemia.
Recent developments in the field of cerebral circulation and metabolism are reviewed, with emphasis on circulatory and metabolic events that have a bearing on brain damage incurred in ischemia. The first part of the treatise reviews aspects of cerebral metabolism that provide a link to the coupling of metabolism and blood flow, notably those that lead to a perturbation of cellular energy state, ionic homeostasis, and phospholipid metabolism. In the second part, attention is focused on the derangement of energy metabolism and its effects on ion fluxes, acid-base homeostasis, and lipid metabolism. It is emphasized that gross brain damage, involving edema formation and infarction, is enhanced by tissue acidosis, and that neuronal damage, often showing a pronounced selectivity in localization, appears related to a disturbed Ca2+ homeostasis, and to Ca2+-triggered events such as lipolysis and proteolysis.
Regional ischemia and acute spinal cord injury, in experimental feline models, are both associated with distinct free radical pathology which affects the predominant membrane lipids in the ischemic or traumatized tissues. In these models, the polyunsaturated fatty acids are selectively lost from the membrane phospholipids while saturated ones are not, because the unsaturated lipids are very susceptible to free radical damage. Cholesterol, a major component of plasma membranes and myelin, is also adversely affected by free radical reactions. The characteristic lipid losses were analyzed by gas chromatography and mass spectrometry. The consumption of a major CNS antioxidant, ascorbic acid, in the ischemic or traumatized tissues occurs before the loss of the lipids, and is an important factor in establishing the free radical nature of some of the pathologic changes. A practical, clinically-oriented consideration in these studies in the question of precisely what factors lead to the irreversible changes. In the regional cerebral ischemia model, wherein one middle cerebral artery is occluded in the cat, there is a period of approximately two hours during which the situation is reversible; removal of the occluding clip before 2 hours in this model results in no discernible infarction and no clinical deficits. Therefore, whatever changes have occurred up to this time do not constitute irreversibility. In a somewhat similar way, acute spinal cord impact models result in minimal, initial structural damage; by 4 hours, only 25% of axons show periaxonal swelling and some myelin fragmentation by electron microscopy. In regional cerebral ischemia models there is an immediate 70-80% decline in blood flow following occlusion, but at three hours, this is reduced further to 90-95%. In the spinal cord impact model, major decreases in blood flow occur 2-3 hours after injury at the site of the lesion. These declines in blood flow appear to coincide to some degree with irreversibility and amplification of morpholigic damage, and could be the result of lipid peroxides, which are products of lipid free radical reactions, inhibiting the synthesis of PGI2. The latter is constantly produced by endothelium and counteracts the pro-aggregating properties of thromboxane A2 in platelets. Unfortunately, lipid peroxides selectively inhibit the synthesis of PGI2 and result in platelet-induced micro-occlusions. We confirmed the hypothesis by examining the microcirculation in the ischemic or traumatized tissues using scanning electron microscopy. There is sequential development, after the first hour, of platelet and leucocyte adherance, endothelial cell damage, and finally micro-occlusions, in both model systems. Treatment of the regional cerebral ischemia model with large doses of methohexital, a short-acting lipid-doluble barbiturate, prevented: the lipid free radical changes, the pathologic consumption of ascorbic acid, the microcirculatory pathology and gross and histologic evidence of cerebral infarction. This study demonstrates that pathologic lipid free radical reactions can result in marked amplification and acceleration of irreversible tissue damage by adversely affecting PGI2 synthesis, and thereby result in the initiation of the intravascular coagulation process.
: The influence of complete and pronounced incomplete cerebral ischemia on cortical concentrations of reduced (GSH) and oxidized (GSSG) glutathione was studied in lightly anaesthetized (70% N2 O) rats. GSH was extracted with HCl-methanol-perchloric acid and GSSG with trichloroacetic acid in the presence of N-ethylmaleimide and measured fluorometrically, giving normal concentrations in cortical tissue of about 2 and 0.01 μmol.g−1 respectively. Reversible complete ischemia was induced by increasing the intracranial pressure to above the systolic blood pressure by infusing mock CSF into the cisterna magna. Reversible pronounced incomplete ischemia was induced by bilateral carotid artery clamping combined with hypovolemic hypotension. Whether complete or incomplete, a 30-min ischemic period caused a similar decrease in cortical GSH concentration (to about 90% of control) without any concomitant accumulation of GSSG in the tissue (or in CSF). Prolongation of the ischemic period (complete ischemia) to maximally 120 min caused an almost linear decrease of the tissue glutathione concentration to 45% of the preischemic value. During subsequent recirculation following a 30 min period of either complete or pronounced incomplete ischemia, there was a further decrease in cortical GSH concentrations without a reciprocal increase in GSSG concentrations. Lipid peroxidation (verified by determination of malondialdehyde production) induced in brain cortical tissue in vitro caused oxidation of tissue GSH with accumulation of GSSG. As the observed decrease in GSH during brain ischemia in vivo was not accompanied by any reciprocal increase in GSSG the results fail to support the hypothesis that peroxidative damage occurs during or following brain ischemia. The finding of an unchanged GSSG concentration does, however, not exclude the possibility of an increased turnover rate in the glutathione reductase reaction. It is concluded that the observed decrease in tissue GSH concentration mainly reflects a decrease in the glutathione pool size, due to an imbalance between breakdown and synthesis secondary to tissue energy failure.
alpha-Lipoic acid (thioctic acid) was tested for its neuroprotective activity in a Mongolian gerbil model of forebrain ischemia/reperfusion. Adult gerbils were treated for 7 days with two intraperitoneal injections per day of alpha-lipoic acid (20 mg/kg), vehicle or saline and on the 7th day the animals were subjected to 5 min of forebrain ischemia. Ischemic injury was assessed by monitoring the increases in locomotor activity and from the extent of damage to the CA1 hippocampal pyramidal cell layer after 5 days of recovery. By both criteria, alpha-lipoic acid was neuroprotective against ischemia/reperfusion evoked cerebral injury.
The status of glutathione (GSH) and protein thiol homeostasis was examined in rat brain regions during reperfusion after moderate and severe cerebral ischemia. GSH levels were decreased in brain regions during reperfusion for 1 hr after moderate or severe ischemia for 0.5 hr. Maximal loss of GSH (50-66%) was observed in the striatum and hippocampus. The GSH lost from the brain regions was essentially recovered as protein-glutathione mixed disulfide (PrSSG) with concomitant loss of protein thiols (PrSH). The activities of enzymes such as Na+K+ ATPase, NADH dehydrogenase and glutathione reductase were also inhibited but were restored after incubation of the brain homogenate with dithiothreitol. The depletion of GSH was also accompanied by an increase in the levels of malondialdehyde and reactive oxygen species. The total GSH recovered as sum of GSH and PrSSG was significantly higher than the sham-operated controls in the hippocampus and striatum after 1 hr of reperfusion, after moderate ischemia for 0.5 hr, and at the end of 24 hr of reperfusion the GSH-protein thiol homeostasis was restored. In contrast after 1 hr of reperfusion after severe ischemia, the GSH recovered as sum of GSH and PrSSG was not significantly different from sham-operated controls and at the end of 24 hr, 7 of 9 animals died. The recuperation of the brain from oxidative stress during reperfusion after moderate ischemia was thus preceded by increased recovery of total GSH essentially in the form of PrSSG. Thus, rapid restoration of thiol homeostasis in the brain during reperfusion may help the brain recover from reperfusion injury.
alpha-Lipoic acid, which plays an essential role in mitochondrial dehydrogenase reactions, has recently gained considerable attention as an antioxidant. Lipoate, or its reduced form, dihydrolipoate, reacts with reactive oxygen species such as superoxide radicals, hydroxyl radicals, hypochlorous acid, peroxyl radicals, and singlet oxygen. It also protects membranes by interacting with vitamin C and glutathione, which may in turn recycle vitamin E. In addition to its antioxidant activities, dihydrolipoate may exert prooxidant actions through reduction of iron. alpha-Lipoic acid administration has been shown to be beneficial in a number of oxidative stress models such as ischemia-reperfusion injury, diabetes (both alpha-lipoic acid and dihydrolipoic acid exhibit hydrophobic binding to proteins such as albumin, which can prevent glycation reactions), cataract formation, HIV activation, neurodegeneration, and radiation injury. Furthermore, lipoate can function as a redox regulator of proteins such as myoglobin, prolactin, thioredoxin and NF-kappa B transcription factor. We review the properties of lipoate in terms of (1) reactions with reactive oxygen species; (2) interactions with other antioxidants; (3) beneficial effects in oxidative stress models or clinical conditions.
alpha-Lipoic acid, an essential cofactor in mitochondrial dehydrogenases, has recently been shown to be a potent antioxidant in vitro, as well as being capable of regenerating vitamin E in vitro. In this study, using a new animal model for rapid vitamin E deficiency in adult animals and a new technique for tissue extraction of oxidized and reduced alpha-lipoic acid, we examined the antioxidant action of alpha-lipoic acid in vivo. Vitamin E-deficient adult hairless mice displayed obvious symptoms of deficiency within five weeks, but if the diet was supplemented with alpha-lipoic acid the animals were completely protected. At five weeks on a vitamin E-deficient diet animals exhibited similar decreases in tissue vitamin E levels, whether supplemented or unsupplemented with alpha-lipoic acid: vitamin E levels in liver, kidney, heart, and skin decreased 70 to 85%; levels in brain decreased only 25%. These data show that there was no effect of alpha-lipoic acid supplementation on vitamin E tissue concentrations, arguing against a role for alpha-lipoic acid in regenerating vitamin E in vivo.
Iron catalyzes the formation of damaging reactive species during cerebral reperfusion. Brain iron concentration is highest at birth, so the brain of the asphyxiated newborn may be at increased risk of iron-dependent injury. We investigated whether the ferric iron chelator deferoxamine could reduce hypoxic-ischemic brain injury in neonatal rats. Because deferoxamine has concentration-dependent activities other than iron chelation, we measured brain deferoxamine levels and calculated deferoxamine pharmacokinetic parameters.
We produced hypoxic-ischemic injury to the right cerebral hemisphere of 7-day-old rats by right common carotid artery ligation followed by 2.25 hours of hypoxia in 8% oxygen. At 5 minutes of recovery from hypoxia the rats received 100 mg/kg deferoxamine mesylate or saline subcutaneously. Rats (saline, n = 33; deferoxamine, n = 38) were killed at 42 hours of recovery to assess early acute edema by measurement of hemispheric water content. Other rats (saline, n = 31; deferoxamine, n = 32) were killed at 30 days of age for morphometric determination of right hemisphere atrophy. In still other rats, we measured deferoxamine levels in blood and brain after hypoxia-ischemia.
Deferoxamine significantly reduced right hemisphere injury as measured by early water content (P < .01) and later atrophy (P = .019). Deferoxamine brain levels peaked between 100 and 200 mumol/L at 40 to 60 minutes after injection and exceeded serum levels by +/- 70%.
Deferoxamine administered after induction of cerebral hypoxia-ischemia reduces injury in 7-day-old rats. Deferoxamine concentrates in the brain at levels between 100 and 200 mumol/L. At the concentrations achieved, deferoxamine might protect the brain through mechanisms unrelated to its ability to chelate iron.
Models for studying long-term recovery tbllowing forebrain ischemia in the rat. A 2-vessel occlusion model
- M L Smith
- G Bendek
- N Dahlgren
- I Rosen
- T Wieloch
- B K Siesjo
Smith, M.L., Bendek, G., Dahlgren, N., Rosen, I., Wieloch, T. and Siesjo, B.K., Models for studying long-term recovery tbllowing forebrain ischemia in the rat. A 2-vessel occlusion model, Acta Neurol. Scand., 69 (1984) 385-401.
Desferrioxamine posttreatment reduces ischemic brain injury in neonatal rats
- Palmer
Models for studying long-term recovery following forebrain ischemia in the rat. A 2-vessel occlusion model
- Smith