Heart Injury Research Articles

UW Supplementation with AP39 Improves Liver Viability Following Static Cold Storage.

Static cold storage of donor livers at 4°C incompletely arrests metabolism, ultimately leading to decreases in ATP levels, oxidative stress, cell death, and organ failure. Hydrogen Sulfide (H2S) is an endogenously produced gas, previously demonstrated to reduce oxidative stress, reduce ATP depletion, and protect from ischemia and reperfusion injury. H2S is difficult to administer due to its rapid release curve, resulting in cellular death at high concentrations. AP39, a mitochondrially targeted, slow-release H2S donor, has been shown to reduce ischemia-reperfusion injury in hearts and kidneys. Thus, we investigated whether the addition of AP39 during 3-day static cold storage can improve liver graft viability. At the end of storage, livers underwent six hours of acellular normothermic machine perfusion, a model of transplantation. During simulated transplantation, livers stored with AP39 showed reduced resistance, reduced cellular damage (ALT and AST), and reduced apoptosis. Additionally, bile production and glucose, as well as energy charge were improved by the addition of AP39. These results indicate that AP39 supplementation improves liver viability during static cold storage.

Causality of genetically proxied immunophenotypes on cardiovascular diseases: a Mendelian randomization study.

Cardiovascular diseases (CVDs) stand as the foremost global cause of mortality, prompting a growing interest in using the potential of immune cells for heart injury treatment. This study aims to assess the causal association between immune cells and CVDs. A total of 731 immune cells were derived from a previously published genome-wide association study (GWAS), which included approximately 22 million genetic variants among 3,757 individuals of Sardinian ancestry. Genetic associations with atrial fibrillation (AF), heart failure, coronary artery disease, myocardial infarction and stroke were extracted from large-scale GWAS. A two-sample Mendelian randomization (MR) analysis was used to assess the causal association between immune cells and CVDs. Replication MR analysis based on FinnGen dataset and meta-analysis are sequentially conducted to validate causal relationships. Collectively, genetically predicted 4 immune cell traits were associated with AF and 5 immune cell traits were associated with stroke. Increased levels of IgD- CD38dim absolute count were associated with a higher susceptibility to AF, while increased expression of CD14+ CD16+ monocytes, CD62L on CD62L+ myeloid dendritic cells, and CD16 on CD14- CD16+ monocytes were linked to a decreased susceptibility to AF. Additionally, an elevated susceptibility to stroke was linked to an increase in the percentage of CD39+ resting Tregs and heightened CD27 expression on IgD- CD38+ cells. Conversely, a decreased susceptibility to stroke was associated with increased CD40 expression on monocytes, particularly on CD14+ CD16+ and CD14+ CD16- monocytes, with the latter two showing the most compelling evidence. This study identified several immune cell traits that have a causal relationship with CVDs, thus confirming that immune cells play an important role in the pathogenesis of these diseases.

Ilex pubescens inhibits pyroptosis post-myocardial infarction through suppression of the ROS/NLRP3 pathway

IntroductionIlex pubescens (IPES), a traditional Chinese herb widely used in cardiovascular diseases, has shown potential anti-inflammatory capabilities in myocardial infarction. Reactive Oxygen Species (ROS) and the NOD-like Receptor Protein 3 (NLRP3) pathway are significant contributors to aseptic inflammation in heart diseases. This study aims to elucidate the primary mechanism by which IPES inhibits pyroptosis post-myocardial infarction. MethodsBy ligating the left coronary artery in C57BL/6 mice, a myocardial infarction model was established to be conducted in vivo. To establish pyroptosis in vitro, primary neonatal cardiomyocytes, extracted from the hearts of Sprague-Dawley rats, were treated in an oxygen-glucose deprivation way. ROS scavenger, NLRP3 inhibitor, and NLRP3 was overexpressed by adenovirus to confirm IPES inhibiting myocardial pyroptosis through the ROS/NLRP3 pathway. ResultsIn vivo, IPES exerted significant cardioprotective effects, as evidenced by reducing heart injury, improving cardiac function, and decreasing serum markers of cardiac damage. Furthermore, IPES treatment significantly inhibits ROS generation and reduces the expression levels of NLRP3 and its downstream pyroptosis-related proteins. In vitro, IPES therapy significantly decreased cell damage and pyroptosis in a concentration-dependent manner in an oxygen-glucose deprivation/re-oxygenation (OGD/R) cell model. Additionally, IPES demonstrates synergistic cardiomyocyte protection with the ROS scavenger NAC, whereas its inhibition of pyroptosis is not significantly different from that of the NLRP3 inhibitor. More importantly, the inhibitory impacts of IPES on pyroptosis were partially reversed by NLRP3 overexpression. The active components of IPES exhibit the ability to stably and efficiently bind with NLRP3. DiscussionThese results demonstrate that IPES inhibit pyroptosis post-MI by suppressing the ROS/NLRP3 pathway, providing a new insight into its potential application in treating MI.

CARDIAC ULTRASOUND ALTERATIONS IN INDIVIDUALS WITH PNEUMONIA RELATED TO COVID-19 INFECTION

A wide range of cardiac effects are observed during the acute phase of COVID-19. Interestingly, troponin levels are raised in 8–28% of instances, while systolic myocardial dysfunction symptoms are not always evident. Subclinical myocardial dysfunction is more common and is commonly defined as a decrease in the left ventricle's global longitudinal strain (LV GLS). Up to 80% of individuals exhibit this alteration while they are in the hospital. LV GLS is a crucial component in risk assessment for follow-up care and a strong independent predictor of in-hospital mortality. The first results on the long-term cardiovascular effects of COVID-19 one year after hospitalization are presented in this study. One year after discharge, we found that patients with COVID-19 pneumonia had a negative trend in LV GLS and deformation metrics in the apical and certain middle segments of the LV myocardium, as compared to data collected three months after discharge. The purpose of the study is to look at the prevalence and clinical significance of long-term heart injury following COVID-19. In order to do this, we examined patient data and categorized patients a year following hospital discharge according to their LV GLS values. This method aids in comprehending the clinical ramifications of long-term cardiac injury after COVID-19.

Brachial thoracic bullet wound with damage to the left atrium

Bullet wounds to the heart on the battlefield are quite rare. The victims usually die in the near future after being in[1]jured. The injuring agent most often pierces through the heart, thereby causing massive bleeding and cardiac arrest. All rare, unique cases when the wounded remained alive are associated either with the loss of kinetic energy of the injuring agent when the defeat occurs at the limit of flight range, or with a «behind the barrier» defeat when a bullet or fragment initially penetrates the «barrier» (armor, vehicle, ricochet from weapons or other solid objects, etc.). Injuries, when a bullet hits the shoulder, ricochets off the bones of the skeleton or spine and hits the heart, are found in isolated cases.In the presented clinical observation, the combatant was wounded in the left shoulder. At the stages of medical evacuation, a chest injury with heart damage and the presence of a foreign body was revealed. Initially, the wound proceeded without hemodynamic disorders, and only 36 hours after the injury, the first symptoms of a violation of the cardiovascular system appeared. As a matter of urgency, the wounded man was transferred by the intensive care team to a specialized cardiac surgery department, where emergency surgery was performed in conditions of artificial circulation. The postoperative period was smooth. The victim is currently receiving rehabilitation treatment. Heart injuries in combat conditions are highly relevant and are an extremely serious problem of the medical service at all stages of evacuation, diagnosis and treatment. The difficulties in diagnosing heart wounds are associated with the lack of the necessary hardware and diagnostic base near the line of contact and the extremely rapid development of the terminal condition. High mortality rates are due to acute cardiac disorders (cardiac tamponade, damage to the coronary arteries, massive bleeding). Subjective signs of cardiac injuries are often absent due to the admission of such a category of patients in an unconscious state. In this clinical case, timely diagnosis at the stages of medical care and interdisciplinary interaction made it possible to urgently refer a victim with a brachiothoracic bullet wound to the stage of specialized care.

#1116 Hyperuricemia worsens bacterial sepsis by suppressing neutrophil functions in CKD

Abstract Background and Aims Patients with kidney disease, especially those on dialysis, are more susceptible to infections such as peritonitis, sepsis, pneumonia, and are at a higher risk for infection-related mortality. Pathogenic mechanisms underlying the secondary immunodeficiency in kidney disease include gut dysbiosis and barrier dysfunction, persistent inflammation, immune paralysis due to increased levels of immunoregulatory metabolites (e.g. uric acid) and proteins (e.g. FGF23) [1]. Currently, it is unknown whether CKD-related hyperuricemia may contribute to the immune paralysis in this context. We hypothesized that hyperuricemia (HU) may aggravate the innate immune response to infection in CKD in mice. Method Mono- and polybacterial sepsis was induced by LPS injection or cecal ligation and puncture in Alb-creERT2;Glut9lox/lox mice with HU and/or CKD, and in Glut9lox/lox (healthy) control mice. After 24 hours, systemic inflammation was evaluated by measuring serum cytokine levels, immune cell activation and recruitment, and neutrophil extracellular trap release. Tissue injury in liver, heart, and kidney was assessed by performing RT-qPCR and immunohistochemistry. In addition, kidney function was determined by measuring the glomerular filtration rate (GFR). Additionally, mice were treated with urate-lowering therapy to reduce serum uric acid levels and the immune response and functional outcomes after sepsis is quantified. Results We found that both mono- and polybacterial sepsis caused systemic inflammation as indicated by an increased number of blood neutrophils (see Figure), neutrophil activation and pro-inflammatory cytokine levels as compared to the PBS-treated or sham-operated control groups in Glut9lox/lox healthy mice, respectively. Mice with sepsis also displayed a slightly worsened kidney function. Interestingly, HU significantly increased neutrophil numbers but decreased their activation status and the ability of neutrophils to form neutrophil extracellular traps in Alb-creERT2;Glut9lox/lox mice with sepsis as compared to the control groups, which was further aggravated in mice with CKD-related HU (CKD+HU). This impaired inflammatory response was partially reversible by lowering serum uric acid with febuxostat. Conclusion Our results identify hyperuricemia related or unrelated to kidney disease as immune regulator in bacterial infection by suppressing neutrophil functions in mice. Specifically targeting uric acid may help to overcome the secondary immunodeficiency related to kidney disease during infection but enhances sterile inflammation [2].

#1131 Significant reno-cardio-metabolic protection by the food additive Flexovital in a murine model combining unilateral nephrectomy and Western diet

Abstract Background and Aims Cardiovascular complications are major threats in advanced renal failure and metabolic dysfunction with several unmet medical needs. This study aimed to investigate the therapeutic effects of a special food additive (FLEXOVITAL) in a newly developed mouse model of reno-cardio-metabolic disease, induced by moderate renal failure in combination with a special Western diet. Method Male C57BL/6J mice (4 weeks old, n = 18) were subject to unilateral nephrectomy (UNX), fed a Western diet rich in fat carbohydrates and salt (WD), and were followed for 12 weeks compared with SHAM-operated mice on standard chow (n = 19). One group of UNX+WD mice (n = 8) was fed a food additive (FLEXOVITAL; FLX) containing extracts of Rhodiola rosea, beetroot, and the amino acids arginine and citrulline. Body weight (BW), blood pressure (tail-cuff), endothelial-dependent vasorelaxation (myograph), glucose metabolism (IPGTT), body fat and lean mass composition (DEXA), adipocyte area, renal function (Glomerular Filtration Rate (GFR) by plasma clearance of FITC-inulin), and mitochondrial function (Oroboros, High-resolution respirometry) were measured together with biochemical analysis of heart injury (Troponin-I), inflammation (IL6) and histological analyses of the kidney and heart. Results BW gain was seen in the UNX+WD and SHAM group, and was 25% less in the FLX group (p < 0.05). The fat/lean-mass ratio increased by 17% (p < 0.01) and the adipocyte area by 31% (p < 0.001) in the UNX+WD group but was virtually normalized in the FLX group (p < 0.01). Fasting and non-fasting glucose levels became elevated in the UNX+WD group and were reduced in the FLX group (p < 0.05). Impaired glucose clearance in the UNX+WD group, was partially prevented by FLX. BP significantly increased in the UNX+WD group (MAP = 78 → 90 mmHg, p < 0.001), and was largely prevented by FLX (MAP = 82 mmHg, p < 0.01). Endothelial function was significantly impaired in the UNX+WD group (p < 0.01) and partially preserved in the FLX group (p < 0.05). GFR was reduced by almost 60% in the UNX+WD group but improved with a 75% protective effect in the FLX group (p < 0.05). Significant glomerular injuries with mesangial proliferation were observed in the UNX+WD group (p < 0.001) but were less pronounced in the FLX group (p < 0.01). Tubular injury score (1-10) increased from 1 in SHAM to 6.5 in the UNX+WD group and was partly protected (4.5) in the FLX group (p < 0.05). Troponin-I levels were 15 pg/ml in the SHAM group, markedly increased in the UNX+WD group (p < 0.001), whereas completely reversed in the FLX group (p < 0.01). No significant histological cardiac injuries or deviations could be demonstrated. Inflammatory activity (IL6) increased by 88% in the UNX+WD there was a trend of reduction in mice with FLX. Mitochondrial oxygen efficiency (P/O ratio) was improved in the kidneys of the FLX group compared to the UNX+WD group (p < 0.05). Conclusion In the present multiorgan disease model, significant renal, cardiovascular, and metabolic dysfunction/injuries emerge in mice with a moderate reduction of renal function when fed a Western diet rich in fat, carbohydrates, and salt. Protective effects were noted by dietary FLX treatment in most functional assessments made in the model. This indicates FLX is a potential new treatment in patients with reno-cardio-metabolic disease. The next phase involves confirming these findings in the clinical setting.

Effects of fingolimod on heart injury induced by renal ischemia-reperfusion

Background. Renal ischemia-reperfusion injury (IRI) is one of the inevitable complications of surgery. The evidence shows that fingolimod, with its anti-inflammatory effects, can play a protective role in renal IRI. The main aim of the present study was to investigate the role of fingolimod against renal IRI in the heart tissue. Methods. Twenty-four male Wistar rats (220±20g) were treated with a single dose of fingolimod (1mg/kg) by intraperitoneal injection before the induction of kidney IRI. At the end of the reperfusion period, the oxidative stress biomarker (malondialdehyde) and antioxidant biomarkers (catalase, superoxide dismutase, glutathione, glutathione peroxidase, and total antioxidant capacity) were evaluated in the heart tissue. Results. Fingolimod pretreatment could increase cardiac glutathione enzyme activity in the fingolimod+IR group compared to the IR group, which was not statistically significant (P>0.05). The level of total antioxidant capacity in the heart tissue was also significantly increased in the fingolimod+IR group in comparison to the IR group (P<0.05). Conclusion. Fingolimod was able to prevent oxidative stress damage in the heart caused by kidney IR induction by increasing the level of total antioxidant capacity of the heart tissue. It is suggested that future studies evaluate the effects of this drug in clinical trials. Practical Implications. The total antioxidant capacity of the heart, as a distant organ affected by kidney IRI, is increased following fingolimod pre-treatment.

Mitigation of cisplatin-induced cardiotoxicity by Isorhamnetin: Mechanistic insights into oxidative stress, inflammation, and apoptosis modulation

The flavonoid compound Isorhamnetin (IRMN) is known for its considerable pharmacological properties, which include antioxidant and anti-inflammatory effects, as well as significant protective actions on heart health. However, the potential of IRMN to guard against heart damage caused by cisplatin (CP), a common chemotherapeutic agent, and the specific mechanisms involved, remain unexplored areas. This research was designed to investigate how IRMN counters CP-induced heart toxicity. In our study, mice were orally given IRMN at 50 or 150 mg/kg/day for a week, followed by CP injections (5 mg/kg/day) on the third and sixth days. The animals were euthanized under sodium pentobarbital anesthesia (50 mg/kg, intraperitoneally) on the eighth day to collect blood and heart tissues for further examination. Our findings reveal that IRMN administration significantly reduced the heart damage and the elevation of heart injury markers such as cardiac troponin I, creatine kinase, and lactate dehydrogenase induced by CP. IRMN also effectively lowered oxidative stress markers, including reactive oxygen species and malondialdehyde, while boosting ATP production and antioxidants like superoxide dismutase, catalase, and glutathione. The compound’s capability to diminish the levels of pro-inflammatory cytokines like tumor necrosis factor-alpha and interleukin-6, alongside modulating apoptosis-regulating proteins (enhancing Bcl-2 while suppressing Bax and Caspase-3 expression), further underscores its cardioprotective effect. Notably, IRMN modulated the p62–Keap1–Nrf2 signaling pathway, suggesting a mechanism through which it exerts its protective effects against CP-induced cardiac injury. These insights underscore the potential of IRMN as an effective adjunct in cancer therapy, offering a strategy to mitigate the cardiotoxic side effects of cisplatin.

Catecholamine treatment induces reversible heart injury and cardiomyocyte gene expression

BackgroundCatecholamines are commonly used as therapeutic drugs in intensive care medicine to maintain sufficient organ perfusion during shock. However, excessive or sustained adrenergic activation drives detrimental cardiac remodeling and may lead to heart failure. Whether catecholamine treatment in absence of heart failure causes persistent cardiac injury, is uncertain. In this experimental study, we assessed the course of cardiac remodeling and recovery during and after prolonged catecholamine treatment and investigated the molecular mechanisms involved.ResultsC57BL/6N wild-type mice were assigned to 14 days catecholamine treatment with isoprenaline and phenylephrine (IsoPE), treatment with IsoPE and subsequent recovery, or healthy control groups. IsoPE improved left ventricular contractility but caused substantial cardiac fibrosis and hypertrophy. However, after discontinuation of catecholamine treatment, these alterations were largely reversible. To uncover the molecular mechanisms involved, we performed RNA sequencing from isolated cardiomyocyte nuclei. IsoPE treatment resulted in a transient upregulation of genes related to extracellular matrix formation and transforming growth factor signaling. While components of adrenergic receptor signaling were downregulated during catecholamine treatment, we observed an upregulation of endothelin-1 and its receptors in cardiomyocytes, indicating crosstalk between both signaling pathways. To follow this finding, we treated mice with endothelin-1. Compared to IsoPE, treatment with endothelin-1 induced minor but longer lasting changes in cardiomyocyte gene expression. DNA methylation-guided analysis of enhancer regions identified immediate early transcription factors such as AP-1 family members Jun and Fos as key drivers of pathological gene expression following catecholamine treatment.ConclusionsThe results from this study show that prolonged catecholamine exposure induces adverse cardiac remodeling and gene expression before the onset of left ventricular dysfunction which has implications for clinical practice. The observed changes depend on the type of stimulus and are largely reversible after discontinuation of catecholamine treatment. Crosstalk with endothelin signaling and the downstream transcription factors identified in this study provide new opportunities for more targeted therapeutic approaches that may help to separate desired from undesired effects of catecholamine treatment.

Preconditioning with selective autoretroperfusion: In vivo and in silico evidence of washout hypothesis.

Prompt reperfusion of coronary artery after acute myocardial infarction (AMI) is crucial for minimizing heart injury. The myocardium, however, may experience additional injury due to the flow restoration itself (reperfusion injury, RI). The purpose of this study was to demonstrate that short preconditioning (10min) with selective autoretroperfusion (SARP) ameliorates RI, based on a washout hypothesis. AMI was induced in 23 pigs (3 groups) by occluding the left anterior descending (LAD) artery. In SARP-b (SARP balloon inflated) and SARP-nb (SARP balloon deflated) groups, arterial blood was retroperfused for 10min via the great cardiac vein before releasing the arterial occlusion. A mathematical model of coronary circulation was used to simulate the SARP process and evaluate the potential washout effect. SARP restored left ventricular function during LAD occlusion. Ejection fraction in the SARP-b group returned to baseline levels, compared to SARP-nb and control groups. Infarct area was significantly larger in the control group than in the SARP-b and SARP-nb groups. End-systolic wall thickness was preserved in the SARP-b compared to the SARP-nb and control groups. Analyte values (pH, lactate, glucose, and others), measured every 2min during retroperfusion, suggest a "washout" effect as one important mechanism of action of SARP in reducing infarct size. With SARP, the values progressively approached baseline levels. The mathematical model also confirmed a possible washout effect of tracers. RI can be ameliorated by delaying restoration of arterial flow for a brief period of time while pretreating the infarction with SARP to restore homeostasis via a washout mechanism.

DJ-1 preserves ischemic postconditioning-induced cardioprotection in STZ-induced type 1 diabetic rats: role of PTEN and DJ-1 subcellular translocation

BackgroundIschemic postconditioning (IPostC) has been reported as a promising method for protecting against myocardial ischemia-reperfusion (MI/R) injury. Our previous study found that the infarct-limiting effect of IPostC is abolished in the heart of diabetes whose cardiac expression of DJ-1 (also called PARK7, Parkinsonism associated deglycase) is reduced. However, the role and in particular the underlying mechanism of DJ-1 in the loss of sensitivity to IPostC-induced cardioprotection in diabetic hearts remains unclear.MethodsStreptozotocin-induced type 1 diabetic rats were subjected to MI/R injury by occluding the left anterior descending artery (LAD) and followed by reperfusion. IPostC was induced by three cycles of 10s of reperfusion and ischemia at the onset of reperfusion. AAV9-CMV-DJ-1, AAV9-CMV-C106S-DJ-1 or AAV9-DJ-1 siRNA were injected via tail vein to either over-express or knock-down DJ-1 three weeks before inducing MI/R.ResultsDiabetic rats subjected to MI/R exhibited larger infarct area, more severe oxidative injury concomitant with significantly reduced cardiac DJ-1 expression and increased PTEN expression as compared to non-diabetic rats. AAV9-mediated cardiac DJ-1 overexpression, but not the cardiac overexpression of DJ-1 mutant C106S, restored IPostC-induced cardioprotection and this effect was accompanied by increased cytoplasmic DJ-1 translocation toward nuclear and mitochondrial, reduced PTEN expression, and increased Nrf-2/HO-1 transcription. Our further study showed that AAV9-mediated targeted DJ-1 gene knockdown aggravated MI/R injury in diabetic hearts, and this exacerbation of MI/R injury was partially reversed by IPostC in the presence of PTEN inhibition or Nrf-2 activation.ConclusionsThese findings suggest that DJ-1 preserves the cardioprotective effect of IPostC against MI/R injury in diabetic rats through nuclear and mitochondrial DJ-1 translocation and that inhibition of cardiac PTEN and activation of Nrf-2/HO-1 may represent the major downstream mechanisms whereby DJ-1 preserves the cardioprotective effect of IPostC in diabetes.Graphical abstract

Phenotypic and Therapeutic Evaluation of Humanized C3 Transgenic Mice as a Model for C3 glomerulopathy-Like Autoimmune Disease

Abstract C3 glomerulopathy (C3G) encompasses a range of kidney disorders with autoimmune and genetic origins, where dysregulated alternative pathway (AP) complement activation stands as the underlying cause. This study develops a transgenic mouse strain that overexpresses human C3, thereby spontaneously generating a rapidly progressing and severe murine model of C3G. The C3G phenotype observed in humanized C3 transgenic mice may arise from a dysregulated interaction between human C3 protein and various mouse complement proteins, resulting in uncontrolled C3 activation via the AP. Male humanized C3 transgenic mice exhibit increased morbidity early in life. Proteinuria initiates at 4 weeks of age, accompanied by an elevation in the albumin/creatinine ratio. Significantly increased serum levels of ALT, AST, ALP, LDH, and CK in humanized C3 transgenic male mice compared to wild-type mice indicate liver and heart injuries. Moreover, serum T-CHOL and HDL levels are significantly reduced, suggesting anemia and malnutrition. Pathohistological analysis of the kidney reveals various renal lesions. Oral administration of Lnp023, a small-molecule inhibitor of complement factor B, effectively increases body weight and serum hC3 levels, improves anemia, and preserves liver, heart, and renal function. In conclusion, this novel model contributes significantly to unraveling the mechanisms underlying C3G and exploring potential therapeutic interventions.

Sophocarpine attenuates doxorubicin-induced heart injury through inhibition of fibrosis.

Doxorubicin (DOX) is a potent anti-cancer medication that is associated with numerous adverse effects, particularly concerning damage to the heart. This study aimed to investigate the impact of sophocarpine (SOP) on DOX-induced heart injury through both in vivo and in vitro experiments. The experimental techniques employed encompassed echocardiography, hematoxylin/eosin (H&E) staining, Masson staining, immunohistochemical staining, western blotting, and so on. Echocardiography showed that SOP alleviated DOX-induced cardiac dysfunction, as evidenced by the improvements in both left ventricle ejection fraction and left ventricle fractional shortening. DOX caused upregulations of creatine kinase-MB and lactate dehydrogenase, while SOP decreased these indices. Staining methods such as H&E and Masson showed that SOP reversed the pathological changes induced by DOX. DOX elevated the expression levels of fibrosis-associated proteins such as Collagen I, Collagen III, α-SMA, Fibronectin, MMP-2, and MMP-9. However, SOP reversed these changes. Moreover, the study further revealed that SOP inhibited the TGF-β1/Smad3 signaling pathway. These findings imply that SOP has the potential to mitigate DOX-induced heart injury by suppressing fibrosis. The underlying molecular mechanism may involve the inhibition of the TGF-β1/Smad3 signaling pathway.

MORIN, A BIOFLAVONOID, ATTENUATES MYOCARDIAL ISCHEMIA-REPERFUSION INJURY BY ATTENUATING RISK/SAPK PATHWAY

Objective: It is important to address the impact of rising incidence of mortality and morbidity associated with myocardial infarction (MI). There is need to explore new safer and efficacious drugs with novel mechanisms to manage MI. Morin, (2-(2,4-Dihydroxyphenyl)-3, is a bioflavanoid which is found in Maclura cochinchinensis, Maclura tinctoria, Maclura pomifera and leaves of Psidium guajava. It possesses good anti-apoptotic, anti-inflammatory, and antioxidant activity. Hence, we have evaluated the cardio-protective effect of Morin in Myocardial Ischemia-Reperfusion (IR) injury model of rat. Design and method: Male albino Wistar rats were pre-treated with Morin (40 and 80 mg/kg; p.o.) for 28 days and on the 29th day, the chest cavity was opened and myocardial ishemia was induced for 45 minutes by ligatiing the LAD coronary artery. Thereafter, reperfusion was carried out for 60 minutes. The hemodynamic parameters as well as left ventricular pressures (±LV dp/dt and LVEDP) were recorded throughout the ischemia and reperfusion. At the end of the procedure, the blood and heart were collected for evaluation of cardiac-injury markers, antioxidant-oxidant parameters, inflammatory markets, histopathological evaluation and molecular signalling pathway protein expressions. Results: Morin pretreatment for 28 days at 40 mg/kg and 80 mg/kg doses significantly controlled hemodynamic parameters, reduced cardiac injury markers, inflammation and apoptosis and reduced oxidative stress and mitigated histological changes following IR injury in rat heart. Morin also downregulated expression of pro-inflammatory and pro-apoptotic SAPK pathway proteins (p38 and JNK), and upregulated the survival kinase protein expression i.e. RISK pathway (ERK, eNOS). Conclusions: Morin reduced myocardial oxidative stress, inflammation and apoptosis in ischemia-reperfusion induced cardiac injury through upregulation of RISK and downregulation of SAPK pathways proteins.

Examining the Impact of Environmental and Genetic Factors that Influence Sarcospan Expression in the Heart

Objective: Susceptibility to cardiac injury can be hereditary and the most common causes include genetic variations in proteins regulating lipid metabolism, arterial hypertension, diabetes, body-mass index as well as environmental causes such as smoking. Sarcospan (SSPN) is an integral member of the dystrophin-glycoprotein complex (DGC) and has an important role in stabilizing the muscle membrane of striated muscle. Genetic variants in the SSPN gene have been linked with increased cardiovascular disease risk and studies are ongoing to identify underlying mechanisms. Our studies using perfused mouse hearts subjected to acute ischemia/reperfusion injury indicate that SSPN deletion increases infarct size and arrhythmia risk (Hwang et al, IJMS, 2023). In addition, adult SSPN−/− cardiomyocytes were found to have decreased antioxidative capacity and heightened susceptibility to oxidative stress. Therefore, we hypothesize that genetic factors that decrease cardiac SSPN expression will increase cardiac susceptibility of mice exposed to conditions of prolonged oxidative stress. In this study we examine the role of SSPN to heart injury caused by chronic oxidative stress mediated by cigarette smoke (CS). Methods: To assess the impact of chronic oxidative stress conditions on SSPN expression in the heart 2 month-old WT C57BL/6J mice were exposed to 4 months CS. We found that SSPN expression was significantly reduced the CS exposed hearts. Since CS increases oxidative damage and deteriorates antioxidant defenses of the heart and vascular system, we examined the combined impact of SSPN deficiency and chronic oxidative stress. To address this, 7-month-old WT and SSPN−/− male and female mice were exposed to CS for 4 months. The mice were assessed after CS for body composition (EchoMRI), glucose tolerance testing and echocardiography. Tissue histology, immunoblotting of oxidative and inflammatory stress markers, serum inflammatory markers were assessed. Lung fibroblasts were isolated from the smoked and non-smoked groups to evaluate inflammatory, fibrotic, and oxidative stress pathway activation to respective stimuli. Results: Preliminary findings indicate that after CS SSPN−/− hearts exhibit larger areas of myocardial damage than WT mice. Surprisingly, after CS the SSPN−/− mice showed better glucose tolerance than WT mice and no significant changes in body mass. Minor decrements were found in the cardiac function of the CSE mice. Exposure of lung fibroblasts obtained from non-smoked SSPN−/− mice to innate immune ligands revealed activation of specific pro-inflammatory pathways.Conclusions: SSPN-deficiency increases susceptibility to cardiac injury in mice subjected to CS exposure, likely through crosstalk mechanisms that exist between oxidative and inflammatory pathways that SSPN appears to influence. Funding Sources: Florida Department of Health, James and Esther King #21K12. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Baicalin alleviates angiotensin II-induced cardiomyocyte apoptosis and autophagy and modulates the AMPK/mTOR pathway.

As a main extraction compound from Scutellaria baicalensis Georgi, Baicalin exhibits various biological activities. However, the underlying mechanism of Baicalin on hypertension-induced heart injury remains unclear. Invivo, mice were infused with angiotensin II (Ang II; 500 ng/kg/min) or saline using osmotic pumps, followed by intragastrically administrated with Baicalin (5 mg/kg/day) for 4 weeks. Invitro, H9C2 cells were stimulated with Ang II (1 μM) and treated with Baicalin (12.5, 25 and 50 μM). Baicalin treatment significantly attenuated the decrease in left ventricular ejection fraction and left ventricular fractional shortening, increase in left ventricular mass, left ventricular systolic volume and left ventricular diastolic volume of Ang II infused mice. Moreover, Baicalin treatment reversed 314 differentially expressed transcripts in the cardiac tissues of Ang II infused mice, and enriched multiple enriched signalling pathways (including apoptosis, autophagy, AMPK/mTOR signalling pathway). Consistently, Baicalin treatment significantly alleviated Ang II-induced cell apoptosis invivo and invitro. Baicalin treatment reversed the up-regulation of Bax, cleaved-caspase 3, cleaved-caspase 9, and the down-regulation of Bcl-2. Meanwhile, Baicalin treatment alleviated Ang II-induced increase of autophagosomes, restored autophagic flux, and down-regulated LC3II, Beclin 1, as well as up-regulated SQSTM1/p62 expression. Furthermore, autophagy inhibitor 3-methyladenine treatment alleviated the increase of autophagosomes and the up-regulation of Beclin 1, LC3II, Bax, cleaved-caspase 3, cleaved-caspase 9, down-regulation of SQSTM1/p62 and Bcl-2 expression after Ang II treated, which similar to co-treatment with Baicalin. Baicalin treatment reduced the ratio of p-AMPK/AMPK, while increased the ratio of p-mTOR/mTOR. Baicalin alleviated Ang II-induced cardiomyocyte apoptosis and autophagy, which might be related to the inhibition of the AMPK/mTOR pathway.

Protective Effects of Trans-Chalcone on Myocardial Ischemia and Reperfusion Challenge through Targeting Phosphoinositide 3-kinase/Akt-inflammosome Interaction.

Ischemia-reperfusion (IR) injury remains a pivotal contributor to myocardial damage following acute coronary events and revascularization procedures. Phosphoinositide 3-kinase (PI3K), a key mediator of cell survival signaling, plays a central role in regulating inflammatory responses and cell death mechanisms. Trans-chalcone (Tch), a natural compound known for its anti-inflammatory activities, has shown promise in various disease models. The aim of the current study was to investigate the potential protective effects of Tch against myocardial injury induced by ischemia and reperfusion challenges by targeting the PI3K-inflammasome interaction. Experimental models utilizing male rats subjected to an in vivo model of IR injury and myocardial infarction were employed. Administration of Tch (100 μg/kg, intraperitoneally) significantly reduced myocardial injury, as indicated by limited infarct size and decreased levels of the myocardial enzyme troponin. Mechanistically, Tch upregulated PI3K expression, thereby inhibiting the activity of the NOD-like receptor protein 3 inflammasome followed by the activation of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18. Moreover, it mitigated oxidative stress and suppressed vascular-intercellular adhesion molecules, contributing to its cardioprotective effects. The PI3K/Akt pathway inhibitor LY294002 considerably attenuated the beneficial effects of Tch. These findings highlight the therapeutic potential of Tch in ameliorating myocardial injury associated with IR insults through its modulation of the PI3K/Akt-inflammasome axis. The multifaceted mechanisms underlying its protective effects signify Tch as a promising candidate for further exploration in developing targeted therapies aimed at mitigating ischemic heart injury and improving clinical outcomes in cardiovascular diseases characterized by IR injury.

Normothermic Ex Vivo Heart Perfusion With Exosomes From Human Umbilical Cord Mesenchymal Stem Cells Improves Graft Function in Donation After Circulatory Death Hearts.

This study aimed to investigate the cardioprotective effect of exosomes derived from human umbilical cord mesenchymal stem cells on donation after circulatory death (DCD) hearts preserved with normothermic ex vivo heart perfusion (EVHP) in a rat heart transplantation model. Thirty-two male Lewis rats were divided into 2 groups: the control group and the exosome group. The donor-heart rats were subjected to the DCD procedure by suffering a 15-min warm ischemia injury, subsequently preserved with EVHP for 90 min, and then transplanted into recipients via abdominal heterotopic heart transplantation. Vehicle or exosome was added into the perfusate of normothermic EVHP in the control or exosome group. We evaluated left ventricular graft function, myocardial inflammation, and myocardial apoptosis of the donor heart 1.5 h after heart transplantation. Furthermore, we investigate the alternation of myocardial gene expression in the donor hearts between both groups by transcriptome sequencing. The treatment with exosome significantly enhanced cardiac function through increasing left ventricular developed pressure, dp/dtmax, and dp/dtmin of DCD hearts at 90 min after heart transplantation compared with the control group. The myocardial cells in the exosome group exhibited an orderly arrangement without obvious edema. Furthermore, exosome added into perfusate in the exosome group significantly attenuated the level of inflammatory response and apoptosis. Transcriptome sequencing and RT-qPCR showed the phosphoinositide 3-kinase/protein kinase B pathway was activated after exosome treatment. Normothermic EVHP combined with exosome can be a promising and novel DCD heart preservation strategy, alleviating myocardial ischemia-reperfusion injury in the DCD heart.

Pyroptosis inhibitors MCC950 and VX-765 mitigate myocardial injury by alleviating oxidative stress, inflammation, and apoptosis in acute myocardial hypoxia

Acute myocardial infarction (AMI) is a prevalent cardiovascular disease with high morbidity and mortality rates worldwide. Pyroptosis is an inflammatory form of programmed cell death that has been linked to various pathological conditions. However, its exact contribution to the onset and progression of heart injury in AMI has not yet fully elucidated. Herein, we established mouse AMI model by ligating the left anterior descending artery and performed transcriptome analysis during the early phase of AMI. Mouse HL-1 and human AC-16 cardiomyocytes were subjected to hypoxia to simulate ischemic injury in vitro. Our results revealed a significant activation of the inflammatory response at 3 h post-ligation, as confirmed by RNA sequencing. We identified the occurrence of NLRP3 inflammasome-mediated pyroptosis in the cardiac tissues of human cases with AMI, as well as in mouse models of AMI and hypoxia-induced cardiomyocytes, using immunohistochemistry staining and Western blotting assays. Concurrently, pharmacological inhibition of NLRP3 inflammasome-mediated pyroptosis with MCC950 and VX-765 effectively decreased hypoxia-induced cardiomyocytes injury, while mitigating myocardial oxidative stress, apoptosis and inflammation caused by hypoxia. Moreover, the circulating levels of gasdermin D (GSDMD), the pyroptosis executor, were remarkably elevated in the plasma of mice with early AMI and in the supernatant of hypoxia-exposed cardiomyocytes in a time-dependent manner using ELISA and Western blotting. Furthermore, the change in circulating GSDMD positively correlated with Creatine Kinase-MB (CK-MB) in the plasma of early-stage AMI mouse. In summary, these findings indicated a critical role for NLRP3 inflammasome-mediated pyroptosis in the progression of AMI, the administration of MCC950 and VX-765 may be attractive candidate therapeutic approaches for cardiac injury caused by acute hypoxia or even AMI. Additionally, the circulating GSDMD exhibits potential as a newly diagnostic biomarker for AMI.