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Functional deficits after asphyxial cardiac arrest (CA)/cardiopulmonary resuscitation (CPR) in aged mice. Mice were subjected to 5 minutes CA or sham surgery. Functional outcome assessments on day 3 after CA/CPR included neurologic scores (A), rotarod test (B), and open field test (C). Data are presented as median or mean±SEM (n=5/group). **P<0.01. ***P<0.001. ****P<0.0001.
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Background
Animal disease models represent the cornerstone in basic cardiac arrest (CA) research. However, current experimental models of CA and resuscitation in mice are limited. In this study, we aimed to develop a mouse model of asphyxial CA followed by cardiopulmonary resuscitation (CPR), and to characterize the immune response after asphyxial...
Context in source publication
Context 1
... then evaluated functional deficits after this short CA duration in aged mice. After CA/CPR, aged mice exhibited significant impairment in all 3 behavioral tests compared with aged sham mice (n=5 per group; Figure 4), demonstrating the suitability of this model to study the effects of aging in asphyxial CA. ...
Similar publications
Cardiopulmonary arrest (CA) can greatly impact a patient's life, causing long-term disability and death. Although multi-faceted treatment strategies against CA have improved survival rates, the prognosis of CA remains poor. We previously reported asphyxial cardiac arrest (ACA) can cause excessive activation of the sympathetic nervous system (SNS) i...
Citations
... A mouse model reveals that asphyxia CA severely impairs lymphopoiesis, reducing systemic lymphocyte production in the bone marrow and thymus, which are critical for lymphocyte development [45]. This impairment persists after resuscitation and, importantly, this study uncovered potential mechanisms behind this impairment. ...
Background
Mitochondrial transplantation (MTx) has emerged as a novel therapeutic strategy, particularly effective in diseases characterized by mitochondrial dysfunction. This review synthesizes current knowledge on MTx, focusing on its role in modulating immune responses and explores its potential in treating post-cardiac arrest syndrome (PCAS).
Methods
We conducted a comprehensive narrative review of animal and human studies that have investigated the effects of MTx in the context of immunomodulation. This included a review of the immune responses following critical condition such as ischemia reperfusion injury, the impact of MTx on these responses, and the therapeutic potential of MTx in various conditions.
Results
Recent studies indicate that MTx can modulate complex immune responses and reduce ischemia–reperfusion injury post-CA, suggesting MTx as a novel, potentially more effective approach. The review highlights the role of MTx in immune modulation, its potential synergistic effects with existing treatments such as therapeutic hypothermia, and the need for further research to optimize its application in PCAS. The safety and efficacy of autologous versus allogeneic MTx, particularly in the context of immune reactions, are critical areas for future investigation.
Conclusion
MTx represents a promising frontier in the treatment of PCAS, offering a novel approach to modulate immune responses and restore cellular energetics. Future research should focus on long-term effects, combination therapies, and personalized medicine approaches to fully harness the potential of MTx in improving patient outcomes in PCAS.
... We used a logarithmic scaling approach that takes animal weight and specific metabolism into account. 14 ...
... We have chosen male young mice as most previous murine data in cardiac arrest have been performed on male mice. 14,39,40 The focused variable for the current study was age. The very important variable sex has to be addressed in future studies. ...
Background:
The administration of epinephrine after severe refractory hypotension, shock or cardiac arrest restores systemic blood flow and major vessel perfusion but may worsen cerebral microvascular perfusion and oxygen delivery through vasoconstriction. We hypothesized that epinephrine induces significant microvascular constriction in the brain, with increased severity after repetitive dosing and in the aged brain, eventually leading to tissue hypoxia.
Methods:
We investigated the effects of intravenous epinephrine administration in healthy young and aged C57Bl/6 mice on cerebral microvascular blood flow and oxygen delivery using multimodal in vivo imaging, including functional photoacoustic microscopy, brain tissue oxygen sensing, and follow up histologic assessment.
Results:
We report 3 main findings. First, after epinephrine administration, microvessels exhibited severe immediate vasoconstriction (57 ± 6% of baseline at 6 minutes, p<0.0001, n = 6) that outlasted the concurrent increase in arterial blood pressure, while larger vessels demonstrated an initial increase in flow (108 ± 6% of baseline at 6 minutes, p = 0.02, n = 6). Second, oxyhemoglobin decreased significantly within cerebral vessels with a more pronounced effect in smaller vessels (microvessels to 69 ± 8% of baseline at 6 minutes, p<0.0001, n = 6). Third, oxyhemoglobin de-saturation did not indicate brain hypoxia; on the contrary, brain tissue oxygen increased after epinephrine application (tissue PO2 from 31 ± 11 at baseline to 56 ± 12 mmHg, 80% increase, p = 0.01, n = 12). In the aged brains, microvascular constriction was less prominent yet slower to recover compared to young brains, but tissue oxygenation was increased, confirming relative hyperoxia.
Conclusions:
Intravenous application of epinephrine induced marked cerebral microvascular constriction, intravascular hemoglobin de-saturation, and paradoxically, an increase in brain tissue oxygen levels, likely due to reduced transit time heterogeneity.
... Many of the observations drawn from human patients following cardiac arrest are mirrored in mouse models. Both chemical and asphyxial murine models of CA/CPR have demonstrated A c c e p t e d M a n u s c r i p t peripheral blood lymphopenia, as well as splenic and thymic contraction within three days of mouse resuscitation 108,113 . Together, these data indicate that immune derangements are associated with brain injuries even in instances where brain injury was an indirect result of cardiac insufficiency and resulting hypoxia. ...
Background
The nervous and immune systems interact in a reciprocal manner, both under physiologic and pathologic conditions. Literature spanning various CNS pathologies including brain tumors, stroke, traumatic brain injury and de-myelinating diseases describes a number of associated systemic immunologic changes, particularly in the T-cell compartment. These immunologic changes include severe T-cell lymphopenia, lymphoid organ contraction, and T-cell sequestration within the bone marrow.
Methods
We performed an in-depth systematic review of the literature and discussed pathologies that involve brain insults and systemic immune derangements.
Conclusions
In this review, we propose that the same immunologic changes hereafter termed ‘systemic immune derangements’, are present across CNS pathologies and may represent a novel, systemic mechanism of immune privilege for the CNS. We further demonstrate that systemic immune derangements are transient when associated with isolated insults such as stroke and TBI but persist in the setting of chronic CNS insults such as brain tumors. Systemic immune derangements have vast implications for informed treatment modalities and outcomes of various neurologic pathologies.
... The mean arterial blood pressure (MAP) was measured through the right femoral arteries of mice as described previously (65). Briefly, mice were placed into the induction chamber and anesthetized with 5% isoflurane in 30% oxygen balanced with nitrogen, then placed in the supine position and maintained in 1.5% isoflurane via face mask. ...
IgE-mediated anaphylaxis is an acute life-threatening systemic reaction to allergens, including certain foods and venoms. Anaphylaxis is triggered when blood-borne allergens activate IgE-bound perivascular mast cells (MCs) throughout the body, causing an extensive systemic release of MC mediators. Through precipitating vasodilatation and vascular leakage, these mediators are believed to trigger a sharp drop in blood pressure in humans and in core body temperature in animals. We report that the IgE/MC-mediated drop in body temperature in mice associated with anaphylaxis also requires the body's thermoregulatory neural circuit. This circuit is activated when granule-borne chymase from MCs is deposited on proximal TRPV1+ sensory neurons and stimulates them via protease-activated receptor-1. This triggers the activation of the body's thermoregulatory neural network, which rapidly attenuates brown adipose tissue thermogenesis to cause hypothermia. Mice deficient in either chymase or TRPV1 exhibited limited IgE-mediated anaphylaxis, and, in wild-type mice, anaphylaxis could be recapitulated simply by systemically activating TRPV1+ sensory neurons. Thus, in addition to their well-known effects on the vasculature, MC products, especially chymase, promote IgE-mediated anaphylaxis by activating the thermoregulatory neural circuit.
... Cortical blood flow of the brain was measured using a full-field laser perfusion imager (RFLSI III, RWD, Life Science Co., Ltd.) as described previously [20]. A midline scalp incision was performed, and the skull was exposed. ...
We present an ischemic stroke study using our newly-developed PAUSAT system that integrates photoacoustic computed tomography (PACT), high-frequency ultrasound imaging, and acoustic angiographic tomography. PAUSAT is capable of three-dimensional (3D) imaging of the brain morphology, blood perfusion, and blood oxygenation. Using PAUSAT, we studied the hemodynamic changes in the whole mouse brain induced by two common ischemic stroke models: the permanent middle cerebral artery occlusion (pMCAO) model and the photothrombotic (PT) model. We imaged the same mouse brains before and after stroke, and quantitatively compared the two stroke models. We observed clear hemodynamic changes after ischemic stroke, including reduced blood perfusion and oxygenation. Such changes were spatially heterogenous. We also quantified the tissue infarct volume in both stroke models. The PAUSAT measurements were validated by laser speckle imaging and histology. Our results have collectively demonstrated that PAUSAT can be a valuable tool for non-invasive longitudinal studies of neurological diseases at the whole-brain scale.
... Although genetic manipulation is an advantage of mouse models, other than the technical difficulties related to surgery and CPR that can be overcome, a limitation of CA models in mice is that it is almost always induced by potassium chloride, which is an uncommon cause of CA. 30 To reproduce a much more clinically relevant scenario, we developed a new model of nonÀshockable, asphyxia-induced CA in mice. Mortality in controls (around 90%) was close to that observed in nonÀshockable CA in humans, 14 allowing to assess the effects of interventions on cardiovascular and brain injury using a reasonable number of animals. ...
Uncertainty exists regarding whether cyclophilin D (CypD), a mitochondrial matrix protein that plays a key role in ischemia-reperfusion injury, can be a pharmacological target for improving outcomes after cardiac arrest (CA), especially when therapeutic hypothermia is used. Using CypD knockout mice (CypD-/-), we investigated the effects of loss of CypD on short-term and medium-term outcomes after CA. CypD-/- mice or their wild-type (WT) littermates underwent either 5-minute CA followed by resuscitation with/without hypothermia at 33-34 C (targeted temperature reached within minutes after resuscitation), or a sham procedure. Brain and cardiac injury were assessed using echocardiography, neurological scores, MRI and biomarkers. Seven-day survival was compared using Kaplan-Meier estimates. The rate of restoration of spontaneous circulation was significantly higher in CypD-/- mice (with shorter cardiac massage duration) than in WT mice (p<0.05). Loss of CypD significantly attenuated CA-induced release of troponin and S100ß protein, and limited myocardial dysfunction at 150 minutes after CA. Loss of CypD combined with hypothermia led to the best neurological and MRI scores at 24 hours and highest survival rates at 7 days compared to other groups (p<0.05). In animals successfully resuscitated, loss of CypD had no benefits on day-7 survival while hypothermia was highly protective. Pharmacological inhibition of CypD with cyclosporine A combined with hypothermia provided similar day-7 survival than loss of CypD combined with hypothermia. CypD is a viable target to improve success of cardiopulmonary resuscitation but its inhibition is unlikely to improve long-term outcomes, unless therapeutic hypothermia is associated.
... After 5 min, 2 mg/kg vecuronium bromide was intravenously injected for the induction of CA [24] followed by ceasing of the ventilation. The induction of CA was considered when MAP fell below 20 mmHg [25], resulting in pulseless electrical activity (PEA), which took 3-4 min after the injection of the drug. After 5 min following the induction of CA, a 0.005 mg/kg bolus of epinephrine and 1 mg/kg sodium bicarbonate were intravenously administered. ...
Return of spontaneous circulation (ROSC) through cardiopulmonary resuscitation (CPR) after cardiac arrest (CA) causes post-cardiac arrest syndrome (PCAS) due to dysfunction in various organs, which provokes acute kidney injury because of renal ischemia-reperfusion injury. Therapeutic hypothermia (TH) can reduce PCAS after CA and ROSC. However, it needs to be more sophisticated and effective. Hence, we aimed to elucidate the protective effects of olanzapine-induced TH against renal injury in asphyxial CA-induced rats. Every rat’s body temperature was maintained at 33 °C for 6 h after administering olanzapine post-CA and ROSC. Olanzapine-induced TH dramatically increased the survival rate of the rats and ameliorated renal tissue damage. Moreover, it suppressed oxidative stress responses through preservation of mitochondrial function and endoplasmic reticulum stress as the main contributor of oxidative stress. Notably, these actions of olanzapine-induced TH were mediated through the Sirt3-related signaling pathway, including the maintenance of Sirt3 and FOXO3a protein expression and the activation of AMPKα and superoxide dismutase 1 (SOD2, a mitochondrial antioxidant). This study is the first to disclose the protective effects of olanzapine-induced TH against renal injury after CA and ROSC, suggesting that olanzapine-induced TH could be utilized for treating CA followed by ROSC.
... All experimental animals were randomly divided into groups using Quickcalcs. CA/CPR operation was performed as previously described (28)(29)(30)(31). In brief, after tracheal intubation, 1.5% isoflurane was given to maintain anesthesia before cardiac arrest. ...
... Rotarod. Rotarod was performed as previously described (29). Briefly, all animals were trained on daily basis for 3 days before CA/CPR surgery. ...
... In animal experiments, we repeatedly observed the damage of the blood-brain barrier (BBB) in CA mice. However, the BBB damage in CA mice was not as obvious as in stroke mice (28,29). Therefore, we are, for now, unable to determine whether the significant changes in the lncRNA GAS5/miR-137 in the blood of CA/CPR patients are released by astrocyte through BBB, or by the other organs such as heart, kidney and liver, into the blood under the systemic I/R stimulation. ...
Background
Cardiac arrest/cardiopulmonary resuscitation (CA/CPR) represents one of the devastating medical emergencies and is associated with high mortality and neuro-disability. Post-cardiac arrest syndrome (PCAS) is mechanistically ascribed to acute systemic ischemia/reperfusion(I/R) injury. The lncRNA/microRNA/mRNA networks have been found to play crucial roles in the pathogenesis of the hypoxia-responsive diseases. Nonetheless, the precise molecular mechanisms by which lncRNA/miRNA/mRNA axes are involved in the astrocyte–microglia crosstalk in CA/CPR have not been fully elucidated.
Methods
We collected and purified the exosomes from the blood of CA/CPR patients and supernatant of OGD/R-stimulated astrocytes. On the basis of microarray analysis, bioinformatic study, and luciferase activity determination, we speculated that lncRNA GAS5/miR-137 is implicated in the astrocyte–microglia crosstalk under the insult of systemic I/R injury. The regulation of lncRNA GAS5/miR-137 on INPP4B was examined by cellular transfection in OGD/R cell culture and by lateral ventricle injection with miR-137 agomir in CA/CPR mice model. Flow cytometry and immunofluorescence staining were performed to detect the microglial apoptosis, M1/M2 phenotype transformation, and neuroinflammation. Neurological scoring and behavior tests were conducted in CA/CPR group, with miR-137 agomir lateral-ventricle infusion and in their controls.
Results
In all the micRNAs, miR-137 was among the top 10 micRNAs that experienced greatest changes, in both the blood of CA/CPR patients and supernatant of OGD/R-stimulated astrocytes. Bioinformatic analysis revealed that miR-137 was sponged by lncRNA GAS5, targeting INPP4B, and the result was confirmed by Luciferase activity assay. qRT-PCR and Western blotting showed that lncRNA GAS5 and INPP4B were over-expressed whereas miR-137 was downregulated in the blood of CA/CPR patients, OGD/R-stimulated astrocytes, and brain tissue of CA/CPR mice. Silencing lncRNA GAS5 suppressed INPP4B expression, but over-expression of miR-137 negatively modulated its expression. Western blotting exhibited that PI3K and Akt phosphorylation was increased when lncRNA GAS5 was silenced or miR-137 was over-expressed. However, PI3K and Akt phosphorylation was notably suppressed in the absence of miR-137, almost reversing their phosphorylation in the silencing lncRNA GAS5 group. Then we found that GAS5 siRNA or miR-137 mimic significantly increased cell viability and alleviated apoptosis after OGD/R injury. Furthermore, over-expression of miR-137 attenuated microglial apoptosis and neuroinflammation in CA/CPR mice model, exhibiting significantly better behavioral tests after CA/CPR.
Conclusion
LncRNA GAS5/miR-137 may be involved in the astrocyte–microglia communication that inhibits PI3K/Akt signaling activation via regulation of INPP4B during CA/CPR.
Determining myocardial infarction (MI) and mechanical asphyxia (MA) was one of the most challenging tasks in forensic practice. The present study aimed to investigate the potential of fatty acid (FAs) metabolism, and lipid alterations in determining MI and MA. MA and MI mouse models were constructed, and metabolic profiles were obtained by LC-MS-based untargeted metabolomics. The metabolic alterations were explored using the PCA, OPLS-DA, the Wilcoxon test, and fold change analysis. The contents of lipid droplets (LDs) were detected by the transmission scanning electron microscope and Oil red O staining. The immunohistochemical assay was performed to detect CD36 and dysferlin. The ceramide was assessed by LC-MS. PCA showed considerable differences in the metabolite profiles, and the well-fitting OPLS-DA model was developed to screen differential metabolites. Thereinto, 9 metabolites in the MA were reduced, while metabolites were up- and down-regulated in MI. The increased CD36 suggested that MI and MA could enhance the intake of FAs and disturb energy metabolism. The increased LDs, decreased dysferlin, and increased ceramide (C18:0, C22:0, and C24:0) were observed in MI groups, confirming the lipid deposition. The present study indicated significant differences in myocardial FAs metabolism and lipid alterations between MI and MA, suggesting that FAs metabolism and related proteins, certain ceramide may harbor the potential as biomarkers for discrimination of MI and MA.
Objective: Brain ischemia leads to the accumulation of unfolded/misfolded proteins in the endoplasmic reticulum (ER) lumen and consequently, ER stress. To help cells restore ER function, a series of adaptive stress response pathways, collectively termed the unfolded protein response (UPR), are activated. We have previously demonstrated that the UPR pathway initiated by ATF6 is pro-survival in transient ischemic stroke. However, the effect of ATF6 activation on the outcome after permanent ischemic stroke remains unknown. Here, we addressed this knowledge gap.
Method: sATF6-KI mice with functional short-form ATF6 (sATF6) predominantly expressed in forebrain neurons were subjected to two ischemic stroke models: photothrombotic stroke and permanent middle cerebral artery occlusion (pMCAO). Both short-term and long-term functional outcomes were evaluated. Changes in neuroinflammation and cerebrovascular density after pMCAO were also assessed.
Results: Compared to littermate controls, sATF6-KI mice performed significantly better in open field, cylinder, and foot fault tests on day 1 or 3 after photothrombotic stroke. However, on days 7 and 14 after stroke, the performance of these functional tests was not significantly different between groups, which is likely related to mild brain damage associated with this stroke model. Thus, to evaluate the long-term effects of ATF6 activation in permanent stroke, we turned to our pMCAO model. We first found that on day 4 after pMCAO, functional outcome was better, and infarct volumes were smaller in sATF6-KI mice vs controls. Next, the 15-day stroke outcome study indicated that compared to control mice, sATF6-KI mice consistently exhibited improved performance in neurologic scoring, tight rope test, and tape removal test, after pMCAO. Moreover, sATF6-KI mice showed higher vascular density and lower activation of both astrocytes and microglia around stroke regions on day 16 after pMCAO.
Conclusions: Here, we presented the first evidence that activation of the ATF6 UPR branch is protective in permanent ischemic stroke, which further supports the therapeutic potential of targeting the ATF6 pathway in stroke.
