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Folic acid reduces matrix degradation in Ang II-infused apoE null mice. Abdominal aortas were collected from sham operated (left column), Ang II-infused (center column), and Ang II-infused and folic acid (FA, right column) treated apoE null mice 4 weeks after infusion. Tissues were then sectioned and stained for VVG; the right arrow in the VVG sections points to a breakdown of elastin fiber, while the left arrow points to a flattening of elastin fiber. doi:10.1371/journal.pone.0088899.g004
Source publication
We have previously shown that eNOS uncoupling mediates abdominal aortic aneurysm (AAA) formation in hph-1 mice. In the present study we examined whether recoupling of eNOS prevents AAA formation in a well-established model of Angiotensin II-infused apolipoprotein E (apoE) null mice by targeting some common pathologies of AAA. Infusion of Ang II res...
Context in source publication
Context 1
... measurements made with L-NAME, as shown in the black bars of Figure 4A, are done to assess the coupling state of eNOS. Under normal conditions when eNOS is coupled, the addition of the eNOS inhibitor will increase the measured superoxide production, as eNOS is producing NO to scavenge superoxide. ...
Citations
... This systematic review encompasses four animal studies that investigated the impact of the vitamin B family on AAA progression. These studies utilized CaCl2-or angiotensin-induced AAA models [9,[36][37][38]. Among them, two studies examined the impact of vitamin B9 [37,38], one focused on riboflavin [36], and another investigated niacin [9] 3.7.1. ...
... These studies utilized CaCl2-or angiotensin-induced AAA models [9,[36][37][38]. Among them, two studies examined the impact of vitamin B9 [37,38], one focused on riboflavin [36], and another investigated niacin [9] 3.7.1. Animal studies. ...
... Oral folic acid treatment significantly decreased AAA formation, elastin degradation and macrophage infiltration. It also decreased superoxide production and increased H4B bioavailability, a cofactor of eNOS, promoting the recoupling of eNOS and leading to higher NO levels [37]. In another study, the potential benefits of combining folic acid with Nifedipine were investigated. ...
Background
Vitamins D, E, A, B, C, and Omega-3 play crucial roles in modulating inflammatory and oxidative stress pathways, both implicated in abdominal aortic aneurysm (AAA) development. Recent research has explored the potential impact of dietary supplements on AAA progression. The systematic review aims to assess interventional studies investigating the effects of various dietary supplements on the development and severity of abdominal aortic aneurysms.
Method
A systematic search using relevant keywords related to abdominal aortic aneurysm and dietary supplements was conducted across four databases (PubMed, Embase, Scopus, and Web of Science). Quality assessment for animal studies employed SYRCLE and the Cochrane Collaboration Risk of Bias Tool for randomized control trials. The study protocol is registered in PROSPERO under the registry code CRD42023455958.
Results
Supplementation with Omega-3, Vitamins A, C, D, E, and the Vitamin B family exhibited positive effects in AAA progression. These supplements contributed to a reduction in AAA diameter, elastin degradation, inflammatory responses, and reactive oxygen species. Additional supplements such as Zinc, methionine, and phytoestrogen also played roles in mitigating AAA progression.
Conclusion
The findings of this study underscore the potential role of dietary supplements in the progression of AAA. Predominantly based on animal studies, the results indicate that these supplements can limit AAA progression, primarily evidenced by their ability to mitigate inflammatory processes and oxidative stress pathways.
... We and others have demonstrated that endothelial DHFR plays a key role in preserving eNOS coupling activity to attenuate hypertension, aortic aneurysms, and diabetic vascular complications. [21][22][23][24]27,32,[34][35][36][37][38][39][40][41] We have generated a novel endothelial-specific DHFR transgenic mouse strain (tg-EC-DHFR) to investigate the potential therapeutic effect on PH of endothelialspecific DHFR overexpression in vivo ( Figures. 3A-3F). ...
BACKGROUND
Pulmonary hypertension (PH) is a progressive disorder characterized by remodeling of the pulmonary vasculature and elevated mean pulmonary arterial pressure, resulting in right heart failure.
METHODS
Here, we show that direct targeting of the endothelium to eNOS (endothelial nitric oxide synthase) with DAHP (2,4-diamino 6-hydroxypyrimidine; an inhibitor of GTP cyclohydrolase 1, the rate-limiting synthetic enzyme for the critical eNOS cofactor tetrahydrobiopterin) induces human-like, time-dependent progression of PH phenotypes in mice.
RESULTS
Critical phenotypic features include elevation in mean pulmonary arterial pressure, right ventricular systolic blood pressure, and right ventricular/(LV+S) ratio; extensive vascular remodeling of pulmonary arterioles with increased medial thickness/perivascular collagen deposition and increased expression of PCNA (proliferative cell nuclear antigen) and alpha-actin; increased total and mitochondrial superoxide production, reduced tetrahydrobiopterin, and nitric oxide bioavailabilities; and formation of an array of human-like vascular lesions. Intriguingly, novel in-house generated endothelial-specific dihydrofolate reductase (DHFR) transgenic mice were completely protected from the pathophysiological and molecular features of PH upon DAHP treatment or hypoxia. Furthermore, DHFR overexpression with a pCMV-DHFR plasmid transfection in mice after initiation of DAHP treatment completely reversed PH phenotypes. DHFR knockout mice spontaneously developed PH at baseline and had no additional deterioration in response to hypoxia, indicating an intrinsic role of DHFR deficiency in causing PH. RNA-sequencing experiments indicated great similarity in gene regulation profiles between the DAHP model and patients with human PH.
Conclusions
Taken together, these results establish a novel human-like murine model of PH that has long been lacking in the field, which can be broadly used for future mechanistic and translational studies. These data also indicate that targeting endothelial DHFR deficiency represents a novel and robust therapeutic strategy for the treatment of PH.
... When eNOS loses its connection with vital cofactors like tetrahydrobiopterin, it leads to the formation of superoxide anion (O 2 − ) instead of nitric oxide (NO − ), resulting in endothelial dysfunction and vascular disease. Siu et al. confirmed in murine models of AA disease the consequences of uncoupled eNOS [47]. They found uncoupling eNOS with vital cofactor tetrahydrobiopterin (H 4 B) led to the development of abdominal aortic aneurysms (AAA) in hph-1 mice [47]. ...
... Siu et al. confirmed in murine models of AA disease the consequences of uncoupled eNOS [47]. They found uncoupling eNOS with vital cofactor tetrahydrobiopterin (H 4 B) led to the development of abdominal aortic aneurysms (AAA) in hph-1 mice [47]. Interestingly, supplementation with folic acid, known to reestablish the coupling of eNOS by enhancing dihydrofolate reductase (DHFR) function, significantly reduced AAA formation in these mice [48,49]. ...
Aortic aneurysms are responsible for significant morbidity and mortality. Despite their clinical significance, there remain critical knowledge gaps in the pathogenesis of aneurysm disease and the mechanisms involved in aortic rupture. Recent studies have drawn attention to the role of reactive oxygen species (ROS) and their down-stream effectors in chronic cardiovascular diseases and specifically in the pathogenesis of aortic aneurysm formation. This review will discuss current mechanisms of ROS in mediating aortic aneurysms, the failure of endogenous antioxidant systems in chronic vascular diseases, and their relation to the development of aortic aneurysms.
... 7 While there is a lack of human studies assessing total vitamin intake's association with intact and ruptured AAA, animal research and studies in cardiovascular disease (CVD) have shown that vitamin D, vitamin E, folate, riboflavin, vitamin B12, and others may play a role in preventing AAA. [8][9][10][11] However, some studies have conflicting results, possibly due to differences in dosages, genetics, and sex. 9,12 A retrospective Swedish cohort study investigated genetic variations in oxidative stress-related single nucleotide polymorphisms (SNPs) and their interaction with antioxidant vitamin intake, focusing on the incidence of intact and ruptured AAA while considering sex-based ...
... However, animal studies have reported on the role of vitamins D and E, folate, and riboflavin supplementation in preventing AAA formation and progression. [12][13][14][15] Moreover, high intakes of antioxidant-rich vegetables and fruits and adherence to the Mediterranean diet have been associated with reduced risk of AAA. 16,17 Folate (vitamin B9), riboflavin (vitamin B2), vitamin E, vitamin B12, beta-carotene (pro-vitamin A), and vitamin D supplementations have been inversely associated with cardiovascular disease (CVD)/CVD-related outcomes (including AAA) in various observational and interventional studies. ...
... 18,19,63 Upon combining the intake categories for folate and riboflavin, we were able to make an additive vitamin score that could stratify the male population at risk of intact AAA. These findings with respect to AAA risk are further supported by previous in vivo studies 14,15 and show a potential for AAA therapeutics. ...
Aims:
The aim of this study is to investigate how genetic variations in genes related to oxidative stress, intake of antioxidant vitamins, and any potential interactions between these factors affect the incidence of intact abdominal aortic aneurysm (AAA) and its rupture (rAAA), accounting for sex differences where possible.
Methods and results:
The present retrospective cohort study (n = 25 252) uses baseline single-nucleotide polymorphisms (SNPs) and total antioxidant vitamin intake data from the large population-based, Malmö Diet and Cancer Study. Cumulative incidence of intact AAA was 1.6% and of rAAA 0.3% after a median follow-up of 24.3 years. A variant in NOX3 (rs3749930) was associated with higher rAAA risk in males [adjusted hazard ratio (aHR): 2.49; 95% confidence interval (CI): 1.36-4.35] and the overall population (aHR: 1.88; 95% CI: 1.05-3.37). Higher intakes of antioxidant vitamins, riboflavin, and folate were associated with 20% and 19% reduced intact AAA incidence, respectively. Interestingly, the inverse associations between riboflavin and vitamin D intake with intact AAA incidence were stronger in the individuals carrying the NOX3 variant as compared with the wild-type recessive genotype, i.e. by 60% and 66%, respectively (P for interaction < 0.05). Higher riboflavin intake was associated with a 33% male-specific intact AAA risk reduction, while higher intake of vitamin B12 intake was associated with 55% female-specific intact AAA risk increase; both these associations were significantly modified by sex (P for interaction < 0.05).
Conclusions:
Our findings highlight the role of oxidative stress genetic variations and antioxidant vitamin intake in AAA. Although a low AAA/rAAA sample size limited some analyses, especially in females, our findings highlight the need for future randomized controlled trials and mechanistic studies, to explore the potential benefits of antioxidant vitamins while accounting for genetic and sex differences.
... In AAA experimental models, antioxidants including vitamin E, quercetin, resveratrol and apigenin, as well as VSMC-specific catalase overexpression, ablate disease [4]. Some other yet preliminary evidence suggests that Nox NADPH oxidases, uncoupled NO synthases [12] and myeloperoxidase [13] are involved in AAA. In Marfan syndrome, excessive nitric oxide generation [14], oxidative processes [15] and mitochondrial dysfunction [16] appear to contribute to its pathophysiology. ...
... Alpha-ketoglutarate, a pleitropic antioxidant, has been shown to reduce ROS generation in C57BL mice challenged with pancreatic elastase (129). Exogenous antioxidants such as folic acid, vitamin C, and vitamin E have been reported to inhibit ROS production in several animal models such as ApoE −/− mice and elastase-induced rat AAA models (130)(131)(132). However, no confirmatory studies have been performed in clinical subjects much needed to confirm the benefits of these agents in limiting AAA growth. ...
Cumulative evidence has shown that mechanical and frictional forces exert distinct effects in the multi-cellular aortic layers and play a significant role in the development of abdominal aortic aneurysms (AAA). These mechanical cues collectively trigger signaling cascades relying on mechanosensory cellular hubs that regulate vascular remodeling programs leading to the exaggerated degradation of the extracellular matrix (ECM), culminating in lethal aortic rupture. In this review, we provide an update and summarize the current understanding of the mechanotransduction networks in different cell types during AAA development. We focus on different mechanosensors and stressors that accumulate in the AAA sac and the mechanotransduction cascades that contribute to inflammation, oxidative stress, remodeling, and ECM degradation. We provide perspectives on manipulating this mechano-machinery as a new direction for future research in AAA.
... Oxidative stress has been shown to play an important role in the formation of aortic aneurysms including AAA and thoracic aortic aneurysm (TAA) [3,9,[13][14][15][16][17][18][19][20][21][22][23]. We have previously established a novel and critical role of uncoupled endothelial nitric oxide synthase (eNOS) in AAA formation via sustaining oxidative stress to induce matrix metalloproteinase (MMP) activation and matrix degradation [3,[15][16][17][18][19][20][21][22]. ...
... Oxidative stress has been shown to play an important role in the formation of aortic aneurysms including AAA and thoracic aortic aneurysm (TAA) [3,9,[13][14][15][16][17][18][19][20][21][22][23]. We have previously established a novel and critical role of uncoupled endothelial nitric oxide synthase (eNOS) in AAA formation via sustaining oxidative stress to induce matrix metalloproteinase (MMP) activation and matrix degradation [3,[15][16][17][18][19][20][21][22]. We first demonstrated that eNOS uncoupling mediates AAA formation in a novel model of AAA, namely angiotensin II (Ang II) infused hph-1 mice in which 79% of the mice developed AAA within 2 weeks of Ang II infusion, with 14% died of ruptured aneurysm [15]. ...
... Restoration of dihydrofolate reductase (DHFR) function with folic acid (FA) to recouple eNOS markedly attenuated AAA formation in these animals [15]. Moreover, we further demonstrated a novel role of eNOS uncoupling in the development of AAA in Ang II-infused apolipoprotein E (apoE) null mice, a well-established, classical model of AAA, while oral FA administration also effectively restored DHFR function to recouple eNOS, resulting in abrogated aneurysm formation [16]. Indeed, knockout of DHFR in mice facilitating uncoupling of eNOS leads to exaggerated formation of AAA [20]. ...
Aortic aneurysms are prevalent and severe vascular diseases with high mortality from unpredicted ruptures, while the only treatment option is surgical correction of large aneurysms with considerable risk. We have shown that folic acid (FA) is highly effective in alleviating development of aneurysms although not sufficient to completely attenuate aneurysm formation. Here, we examined therapeutic effects on aneurysms of combining FA with Nifedipine as novel and potentially more effective oral medication. Oral administration with FA (15 mg/kg/day) significantly reduced incidence of AAA from 85.71% to 18.75% in Ang II-infused apoE null mice, while combination of FA with Nifedipine (1.5, 5.0 or 20 mg/kg/day) substantially and completely further reduced incidence of AAA to 12.5%, 11.76% and 0.00% respectively in a dose-dependent manner. The combinatory therapy substantially and completely further alleviated enlargement of abdominal aortas defined by ultrasound, vascular remodeling characterized by elastin degradation and adventitial hypertrophy, as well as aortic superoxide production and eNOS uncoupling activity also in a dose-dependent manner, with combination of FA with 20 mg/kg/day Nifedipine attenuating all of these features by 100% to control levels. Aortic NO and H4B bioavailabilities were also dose-dependently further improved by combining FA with Nifedipine. These data establish entirely innovative and robust therapeutic regime of FA combined with Nifedipine for the treatment of aortic aneurysms. The comminatory therapy can serve as a first-in-class and most effective oral medication for aortic aneurysms, which can be rapidly translated into clinical practice to manage the devastating vascular diseases of aortic aneurysms known as silent killers.
... Supplementation with high-dose folate and with the amino acid citrulline can reverse this uncoupling [205,206]. High-dose folate, via induction of increased expression of dihydrofolate reductase, promotes reduction of dihydrobiopterin back to its active tetrahydrobiopterin form [207,208]. Citrulline-more efficiently absorbed and transported to tissues than arginine-is readily converted to arginine within cells, thereby opposing the adverse effect of elevated ADMA on eNOS activity [206,209,210]. ...
Oxidative and dicarbonyl stress, driven by excess accumulation of glycolytic intermediates in cells that are highly permeable to glucose in the absence of effective insulin activity, appear to be the chief mediators of the complications of diabetes. The most pathogenically significant dicarbonyl stress reflects spontaneous dephosphorylation of glycolytic triose phosphates, giving rise to highly reactive methylglyoxal. This compound can be converted to harmless lactate by the sequential activity of glyoxalase I and II, employing glutathione as a catalyst. The transcription of glyoxalase I, rate-limiting for this process, is promoted by Nrf2, which can be activated by nutraceutical phase 2 inducers such as lipoic acid and sulforaphane. In cells exposed to hyperglycemia, glycine somehow up-regulates Nrf2 activity. Zinc can likewise promote glyoxalase I transcription, via activation of the metal-responsive transcription factor (MTF) that binds to the glyoxalase promoter. Induction of glyoxalase I and metallothionein may explain the protective impact of zinc in rodent models of diabetic complications. With respect to the contribution of oxidative stress to diabetic complications, promoters of mitophagy and mitochondrial biogenesis, UCP2 inducers, inhibitors of NAPDH oxidase, recouplers of eNOS, glutathione precursors, membrane oxidant scavengers, Nrf2 activators, and correction of diabetic thiamine deficiency should help to quell this.
... Determination of superoxide production by electron spin resonanceSuperoxide production in BAECs was determined by electron spin resonance (ESR) (eScan, Bruker, Billerica, MA, United States) as we previously published(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37). After treatment, cells were collected in cold modified Krebs/HEPES (KHB) buffer (99 mmol/l of NaCl, 4.69 mmol/l of KCl, 1.03 mmol/l of KH 2 PO 4 , 2.50 mmol/l of CaCl 2 , 1.20 mmol/l of MgSO 4 , 25.0 mmol/l of NaHCO 3 , 5.6 mmol/l of glucose, and 20.0 mmol/l of Na-HEPES, pH 7.35). ...
While new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) constantly emerge to prolong the pandemic of COVID-19, robust and safe therapeutics are in urgent need. During the previous and ongoing fight against the pandemic in China, Traditional Chinese Medicine (TCM) has proven to be markedly effective in treating COVID-19. Among active ingredients of TCM recipes, small molecules such as quercetin, glabridin, gallic acid, and chrysoeriol have been predicted to target viral receptor angiotensin-converting enzyme 2 (ACE2) via system pharmacology/molecular docking/visualization analyses. Of note, endothelial dysfunction induced by oxidative stress and inflammation represents a critical mediator of acute respiratory distress syndrome (ARDS) and multi-organ injuries in patients with COVID-19. Hence, in the present study, we examined whether quercetin, glabridin, gallic acide and chrysoeriol regulate viral receptors of ACE2 and transmembrane serine protease 2 (TMPRSS2), redox modulator NADPH oxidase isoform 2 (NOX2), and inflammatory protein of monocyte chemoattractant protein-1 (MCP-1) in endothelial cells to mediate therapeutic protection against COVID-19. Indeed, quercetin, glabridin, gallic acide and chrysoeriol completely attenuated SARS-CoV-2 spike protein (S protein)-induced upregulation in ACE2 protein expression in endothelial cells. In addition, these small molecules abolished S protein upregulation of cleaved/active form of TMPRSS2, while native TMPRSS2 was not significantly regulated. Moreover, these small molecules completely abrogated S protein-induced upregulation in NOX2 protein expression, which resulted in alleviated superoxide production, confirming their preventive efficacies against S protein-induced oxidative stress in endothelial cells. In addition, treatment with these small molecules abolished S protein induction of MCP-1 expression. Collectively, our findings for the first time demonstrate that these novel small molecules may be used as novel and robust therapeutic options for the treatment of patients with COVID-19, via effective attenuation of S protein induction of endothelial oxidative stress and inflammation.
