Alda-1, an Activator of ALDH2, Improves Postresuscitation Cardiac and Neurological Outcomes by Inhibiting Pyroptosis in Swine

Multi-omics Study of Hypoxic-Ischemic Brain Injury After Cardiopulmonary Resuscitation in Swine

BACKGROUND

Hypoxic-ischemic brain injury is a common cause of mortality after cardiac arrest (CA) and cardiopulmonary resuscitation; however, the specific underlying mechanisms are unclear. This study aimed to explore postresuscitation changes based on multi-omics profiling.

METHODS

A CA swine model was established, and the neurological function was assessed at 24 h after resuscitation, followed by euthanizing animals. Their fecal, blood, and hippocampus samples were collected to analyze gut microbiota, metabolomics, and transcriptomics.

RESULTS

The 16S ribosomal DNA sequencing showed that the microbiota composition and diversity changed after resuscitation, in which the abundance of Akkermansia and Muribaculaceae_unclassified increased while the abundance of Bifidobacterium and Romboutsia decreased. A relationship was observed between CA-related microbes and metabolites via integrated analysis of gut microbiota and metabolomics, in which Escherichia-Shigella was positively correlated with glycine. Combined metabolomics and transcriptomics analysis showed that glycine was positively correlated with genes involved in apoptosis, interleukin-17, mitogen-activated protein kinases, nuclear factor kappa B, and Toll-like receptor signal pathways.

CONCLUSIONS

Our results provided novel insight into the mechanism of hypoxic-ischemic brain injury after resuscitation, which is envisaged to help identify potential diagnostic and therapeutic markers.

Sodium octanoate alleviates cardiac and cerebral injury after traumatic cardiac arrest in a porcine model

INTRODUCTION

Traumatic cardiac arrest (TCA) is a severe condition with a high mortality rate, and patients who survive from TCA face a poor prognosis due to post-resuscitation injury, including cardiac and cerebral injury, which remains a serious challenge. Sodium octanoate has shown protective effects against various diseases. The present study aims to investigate sodium octanoate's protective effects against cardiac and cerebral injury after TCA in a porcine model.

METHODS

The study included a total of 22 male domestic pigs divided into three groups: Sham group (n = 7), TCA group (n = 7), and sodium octanoate (SO) group (n = 8). Hemorrhage was initiated via the right femoral artery by a blood pump at a rate of 2 ml·kg-1·min-1 to establish TCA model. The Sham group underwent only endotracheal intubation and arteriovenous catheterization, without experiencing the blood loss/cardiac arrest/resuscitation model. At 5 min after resuscitation, the SO group received a continuous sodium octanoate infusion while the TCA group received the same volume of saline. General indicators were monitored, and blood samples were collected at baseline and at different time points after resuscitation. At 24 h after resuscitation, pigs were sacrificed, and heart and brain were obtained for cell apoptosis detection, iron deposition staining, oxidative stress detection, and the expression of ferroptosis-related proteins (ACSL4 and GPX4).

RESULTS

Sodium octanoate significantly improved mean arterial pressure, cardiac output and ejection fraction induced by TCA. Serum biomarkers of cardiac and cerebral injury were found to increase at all time points after resuscitation, while sodium octanoate significantly reduced their levels. The apoptosis rates of cardiomyocytes and cerebral cortex cells in the SO group were significantly lower than in the TCA group, along with a reduced area of iron deposition staining. The sodium octanoate also reduced oxidative stress and down-regulated ferroptosis which was indicated by protein level alteration of ACSL4 and GPX4.

CONCLUSION

Our study's findings suggest that early infusion of sodium octanoate significantly alleviates post-resuscitation cardiac and cerebral injury in a porcine model of TCA, possibly through inhibition of cell apoptosis and GPX4-mediated ferroptosis. Therefore, sodium octanoate could be a potential therapeutic strategy for patients with TCA.

Activation of aldehyde dehydrogenase-2 improves ischemic random skin flap survival in rats

Objective

Random skin flaps have many applications in plastic and reconstructive surgeries. However, distal flap necrosis restricts wider clinical utility. Mitophagy, a vital form of autophagy for damaged mitochondria, is excessively activated in flap ischemia/reperfusion (I/R) injury, thus inducing cell death. Aldehyde dehydrogenase-2 (ALDH2), an allosteric tetrameric enzyme, plays an important role in regulating mitophagy. We explored whether ALDH2 activated by N-(1,3-benzodioxol-5-ylmethyl)-2,6-dichlorobenzamide (Alda-1) could reduce the risk of ischemic random skin flap necrosis, and the possible mechanism of action.

Methods

Modified McFarlane flap models were established in 36 male Sprague-Dawley rats assigned randomly to three groups: a low-dose Alda-1 group (10 mg/kg/day), a high-dose Alda-1 group (20 mg/kg/day) and a control group. The percentage surviving skin flap area, neutrophil density and microvessel density (MVD) were evaluated on day 7. Oxidative stress was quantitated by measuring the superoxide dismutase (SOD) and malondialdehyde (MDA) levels. Blood perfusion and skin flap angiogenesis were assessed via laser Doppler flow imaging and lead oxide-gelatin angiography, respectively. The expression levels of inflammatory cytokines (IL-1β, IL-6, and TNF-α), vascular endothelial growth factor (VEGF), ALDH2, PTEN-induced kinase 1 (PINK1), and E3 ubiquitin ligase (Parkin) were immunohistochemically detected. Indicators of mitophagy such as Beclin-1, p62, and microtubule-associated protein light chain 3 (LC3) were evaluated by immunofluorescence.

Results

Alda-1 significantly enhanced the survival area of random skin flaps. The SOD activity increased and the MDA level decreased, suggesting that Alda-1 reduced oxidative stress. ALDH2 was upregulated, and mitophagy-related proteins (PINK1, Parkin, Beclin-1, p62, and LC3) were downregulated, indicating that ALDH2 inhibited mitophagy through the PINK1/Parkin signaling pathway. Treatment with Alda-1 reduced neutrophil infiltration and expressions of inflammatory cytokines. Alda-1 significantly upregulated VEGF expression, increased the MVD, promoted angiogenesis, and enhanced blood perfusion.

Conclusion

ALDH2 activation can effectively enhance random skin flap viability via inhibiting PINK1/Parkin-dependent mitophagy. Moreover, enhancement of ALDH2 activity also exerts anti-inflammatory and angiogenic properties.

EFFECTS OF MESENCHYMAL STEM CELLS ON POSTRESUSCITATION RENAL AND INTESTINAL INJURIES IN A PORCINE CARDIAC ARREST MODEL

ABSTRACT

Objectives: Systemic ischemia-reperfusion triggered by cardiac arrest (CA) and resuscitation often causes postresuscitation multiple organ injuries. Mesenchymal stem cells (MSCs) have been proven to be a promising treatment for regional renal and intestinal ischemia reperfusion injuries. This study aimed to investigate the effects of MSCs on renal and intestinal injuries after cardiopulmonary resuscitation (CPR) in a porcine CA model. Methods: Twenty-two male pigs were randomly assigned to the sham (n = 6), CA/CPR (n = 8), and CA/CPR + MSC (n = 8) groups. Mesenchymal stem cells were differentiated from human embryonic stem cells and then intravenously administered at a dose of 2.5 × 10 6 /kg at 1.5 and 3 d before the CA/CPR procedure. The experimental model was established by 8 min of untreated CA, followed by 8 min of CPR. Renal and intestinal injuries were evaluated based on the serum levels of creatinine, serum urea nitrogen, intestinal fatty acid-binding protein, and diamine oxidase at 1, 2, 4, and 24 h after resuscitation. At the end of the experiment, pathological damage was determined by cell apoptosis and ferroptosis in the renal and intestinal tissues. Results: During CPR, five pigs in the CA/CPR group and seven pigs in the CA/CPR + MSC group were successfully resuscitated. After resuscitation, the serum levels of creatinine, serum urea nitrogen, intestinal fatty acid-binding protein, and diamine oxidase were significantly increased in the CA/CPR and CA/CPR + MSC groups compared with those in the sham group. However, MSC administration significantly decreased the levels of renal and intestinal injury biomarkers compared with those in the CA/CPR group. Cell apoptosis and ferroptosis, which were indicated by the levels of apoptotic cells, iron deposition, lipid peroxidation, antioxidants, and ferroptosis-related proteins, were observed in renal and intestinal tissues after resuscitation in the CA/CPR and CA/CPR + MSC groups. Nevertheless, both were significantly milder in the CA/CPR + MSC group than in the CA/CPR group. Conclusions: MSC administration was effective in alleviating postresuscitation renal and intestinal injuries possibly through inhibition of cell apoptosis and ferroptosis in a porcine CA model.

Aldehyde dehydrogenase 2 and NOD-like receptor thermal protein domain associated protein 3 inflammasome in atherosclerotic cardiovascular diseases: A systematic review of the current evidence

Inflammation and dyslipidemia underlie the pathological basis of atherosclerosis (AS). Clinical studies have confirmed that there is still residual risk of atherosclerotic cardiovascular diseases (ASCVD) even after intense reduction of LDL. Some of this residual risk can be explained by inflammation as anti-inflammatory therapy is effective in improving outcomes in subjects treated with LDL-lowering agents. NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome activation is closely related to early-stage inflammation in AS. Aldehyde dehydrogenase 2 (ALDH2) is an important enzyme of toxic aldehyde metabolism located in mitochondria and works in the metabolism of toxic aldehydes such as 4-HNE and MDA. Despite studies confirming that ALDH2 can negatively regulate NLRP3 inflammasome and delay the development of atherosclerosis, the mechanisms involved are still poorly understood. Reactive Oxygen Species (ROS) is a common downstream pathway activated for NLRP3 inflammasome. ALDH2 can reduce the multiple sources of ROS, such as oxidative stress, inflammation, and mitochondrial damage, thereby reducing the activation of NLRP3 inflammasome. Further, according to the downstream of ALDH2 and the upstream of NLRP3, the molecules and related mechanisms of ALDH2 on NLRP3 inflammasome are comprehensively expounded as possible. The potential mechanism may provide potential inroads for treating ASCVD.

The combination of chest compression synchronized ventilation and aortic balloon occlusion improve the outcomes of cardiopulmonary resuscitation in swine

Aim

The primary mission of cardiopulmonary resuscitation (CPR) is to provide adequate blood flow and oxygen delivery for restoring spontaneous circulation from cardiac arrest (CA) events. Previously, studies demonstrated that chest compression synchronized ventilation (CCSV) improved systemic oxygen supply during CPR, and aortic balloon occlusion (ABO) augments the efficacy of external CPR by increasing blood perfusion to vital organs. However, both them failed to make a significant improvement in return of spontaneous circulation (ROSC). In this study, we investigated the effects of combined CCSV and ABO on the outcomes of CPR in swine.

Methods

Thirty-one male domestic swine were subjected to 8 min of electrically induced and untreated CA followed by 8 min of CPR. CPR was performed by continuous chest compressions and mechanical ventilation. At the beginning of CPR, the animals were randomized to receive intermittent positive pressure ventilation (IPPV, n = 10), CCSV (n = 7), IPPV + ABO (n = 7), or CCSV + ABO (n = 7). During CPR, gas exchange and systemic hemodynamics were measured, and ROSC was recorded. After resuscitation, the function and injury biomarkers of vital organs including heart, brain, kidney, and intestine were evaluated.

Results

During CPR, PaO₂ was significantly higher accompanied by significantly greater regional cerebral oxygen saturation in the CCSV and CCSV + ABO groups than the IPPV group. Coronary perfusion pressure, end-tidal carbon dioxide, and carotid blood flow were significantly increased in the IPPV + ABO and CCSV + ABO groups compared with the IPPV group. ROSC was achieved in five of ten (IPPV), five of seven (CCSV), six of seven (IPPV + ABO), and seven of seven (CCSV + ABO) swine, with the rate of resuscitation success being significantly higher in the CCSV + ABO group than the IPPV group (P = 0.044). After resuscitation, significantly improved myocardial and neurological function, and markedly less cardiac, cerebral, renal, and intestinal injuries were observed in the CCSV + ABO group compared with the IPPV group.

Conclusion

The combination of CCSV and ABO improved both ventilatory and hemodynamic efficacy during CPR, promoted ROSC, and alleviated post-resuscitation multiple organ injury in swine.

ALDA-1 TREATMENT ALLEVIATES LUNG INJURY AFTER CARDIAC ARREST AND RESUSCITATION IN SWINE

ABSTRACT

Introduction: Alda-1, an aldehyde dehydrogenase 2 (ALDH2) activator, has been shown to protect the lung against a variety of diseases including regional ischemia-reperfusion injury, severe hemorrhagic shock, hyperoxia, and so on. The present study was designed to investigate the effectiveness of Alda-1 treatment in alleviating lung injury after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in swine. Methods: A total of 24 swine were randomized into three groups: sham (n = 6), CA/CPR (n = 10), and CA/CPR + Alda-1 (n = 8). The swine model was established by 8 min of electrically induced and untreated CA, and then 8 min of manual CPR. A dose of 0.88 mg/kg of Alda-1 was intravenously injected at 5 min after CA/CPR. After CA/CPR, extravascular lung water index (ELWI), pulmonary vascular permeability index (PVPI), and oxygenation index (OI) were regularly evaluated for 4 h. At 24 h after resuscitation, lung ALDH2 activity was detected, and its injury score, apoptosis, and ferroptosis were measured. Results: After experiencing the same procedure of CA and CPR, five swine in the CA/CPR group and six swine in the CA/CPR + Alda-1 group restored spontaneous circulation. Subsequently, significantly increased ELWI and PVPI, and markedly decreased OI were observed in these two groups compared with the sham group. However, all of them were gradually improved and significantly better in the swine treated with the Alda-1 compared with the CA/CPR group. Tissue analysis indicated that lung ALDH2 activity was significantly decreased in those swine experiencing the CA/CPR procedure compared with the sham group; nevertheless, its activity was significantly greater in the CA/CPR + Alda-1 group than in the CA/CPR group. In addition, lung injury score, and its apoptosis and ferroptosis were significantly increased in the CA/CPR and CA/CPR + Alda-1 groups compared with the sham group. Likewise, Alda-1 treatment significantly decreased these pathological damages in lung tissue when compared with the CA/CPR group. Conclusions: Alda-1 treatment was effective to alleviate lung injury after CA/CPR in a swine model, in which the protective role was possibly related to the inhibition of cell apoptosis and ferroptosis. It might provide a novel therapeutic target and a feasible therapeutic drug for lung protection after CA/CPR.

ALDH2 knockout protects against aortic dissection

Background

The incidence and mortality of aortic dissection (AD) are increasing. In pathological studies, macrophages, T lymphocytes and dendritic cells were found in the tunica media of the aorta. Acetaldehyde dehydrogenase 2 (ALDH₂) gene polymorphisms are associated with a high incidence of hypertension in Asian populations. However, there is no clear evidence of the relationship between ALDH₂ and aortic dissection in Asians. The aim of this study was to investigate the incidence of aortic dissection in different ALDH₂ genotypes and explore changes in the vasculature.

Materials and methods

Three-week-old male mice were administered freshly prepared β-aminopropionitrile solution dissolved in drinking water (1 g/kg/d) for 28 days to induce TAD. An animal ultrasound imaging system was used to observe the formation of arterial dissection and changes in cardiac function. Subsequently, mice were euthanized by cervical dislocation. The aortas were fixed for HE staining and EVG staining to observe aortic elastic fiber tears and pseudoluma formation under a microscope.

Results

Knockout of ALDH₂ mitigated β-aminopropionitrile-induced TAD formation in animal studies. Ultrasound results showed that ALDH₂ knockout reduced the degree of ascending aortic widening and the incidence of aortic dissection rupture. Pathological sections of multiple aortic segments showed that the protective effect of ALDH₂ knockout was observed in not only the ascending aorta but also the aortic arch and descending aorta. The expression levels of genes related to NK CD56bright cells, Th17 cells, T cells and T helper cells were decreased in ALDH₂ knockout mice treated with β-aminopropionitrile for 28 days.

Conclusion

ALDH₂ knockout protects against aortic dissection by altering the inflammatory response and immune response and protecting elastic fibers.

Cardiac Remodeling in Heart Failure: Role of Pyroptosis and Its Therapeutic Implications

Pyroptosis is a kind of programmed cell death closely related to inflammation. The pathways that mediate pyroptosis can be divided into the Caspase-1-dependent canonical pathway and the Caspase4/5/11-dependent non-canonical pathway. The most significant difference from other cell death is that pyroptosis rapidly causes rupture of the plasma membrane, cell expansion, dissolution and rupture of the cell membrane, the release of cell contents and a large number of inflammatory factors, and send pro-inflammatory signals to adjacent cells, recruit inflammatory cells and induce inflammatory responses. Cardiac remodeling is the basic mechanism of heart failure (HF) and the core of pathophysiological research on the underlying mechanism. A large number of studies have shown that pyroptosis can cause cardiac fibrosis, cardiac hypertrophy, cardiomyocytes death, myocardial dysfunction, excessive inflammation, and cardiac remodeling. Therefore, targeting pyroptosis has a good prospect in improving cardiac remodeling in HF. In this review, the basic molecular mechanism of pyroptosis is summarized, the relationship between pyroptosis and cardiac remodeling in HF is analyzed in-depth, and the potential therapy of targeting pyroptosis to improve adverse cardiac remodeling in HF is discussed, providing some ideas for improving the study of adverse cardiac remodeling in HF.