Molecular Characterization of Reactive Oxygen Species in Myocardial Ischemia-Reperfusion Injury

Circadian Rhythm-Dependent Therapy by Composite Targeted Polyphenol Nanoparticles for Myocardial Ischemia-Reperfusion Injury

Myocardial ischemia-reperfusion (IR) injury is a severe rhythmic disease with a high prevalence in the early morning. IR injury has a significant circadian rhythm in reactive oxygen species (ROS) and inflammation levels. The development of rhythmic drugs has become a priority in myocardial IR injury. In this study, resveratrol (RES) and proanthocyanidins (OPC) were utilized to design nanoparticles (NPs), with hyaluronic acid (HA) as the core, grafted with MMP-targeting peptides to improve delivery to injured myocardial regions (HA-RES-OPC-MMP NPs). NPs significantly scavenged ROS, attenuated inflammation, and activated the rhythm gene. Notably, the difference in therapeutic effects on myocardial IR injury in mice at Zeitgeber time (ZT)1 and ZT13 confirms that NPs are rhythm-dependent drugs. At ZT13, echocardiographic and MRI confirm that IR injury in mice was not as severe as at ZT1, yet NPs were also less effective in treatment. Further, Per1/2 knockout mice confirmed the rhythm-dependent treatment of myocardial IR injury by NPs. Molecular studies have shown that rhythmic characteristics of inflammation and Sirt1 transcript levels are the main reasons for the different rhythmic therapeutic effects of NPs. Circadian rhythm-dependent treatment of HA-RES-OPC-MMP NPs has excellent potential for more precise treatment of myocardial IR injury in the future.

DJ-1: Potential target for treatment of myocardial ischemia-reperfusion injury

Ischemic heart disease (IHD) is a significant global health concern, resulting in high rates of mortality and disability among patients. Although coronary blood flow reperfusion is a key treatment for IHD, it often leads to acute myocardial ischemia-reperfusion injury (IRI). Current intervention strategies have limitations in providing adequate protection for the ischemic myocardium. DJ-1, originally known as a Parkinson's disease related protein, is a highly conserved cytoprotective protein. It is involved in enhancing mitochondrial function, scavenging reactive oxygen species (ROS), regulating autophagy, inhibiting apoptosis, modulating anaerobic metabolism, and exerting anti-inflammatory effects. DJ-1 is also required for protective strategies, such as ischemic preconditioning, ischemic postconditioning, remote ischemic preconditioning and pharmacological conditioning. Therefore, DJ-1 emerges as a potential target for the treatment of myocardial IRI. Our comprehensive review delves into its protective mechanisms in myocardial IRI and the structural foundations underlying its functions.

Utilizing pathophysiological concepts of ischemia-reperfusion injury to design renoprotective strategies and therapeutic interventions for normothermic ex vivo kidney perfusion

Normothermic machine perfusion (NMP) has emerged as a promising tool for the preservation, viability assessment, and repair of deceased-donor kidneys prior to transplantation. These kidneys inevitably experience a period of ischemia during donation, which leads to ischemia-reperfusion injury when NMP is subsequently commenced. Ischemia-reperfusion injury has a major impact on the renal vasculature, metabolism, oxygenation, electrolyte balance, and acid-base homeostasis. With an increased understanding of the underlying pathophysiological mechanisms, renoprotective strategies and therapeutic interventions can be devised to minimize additional injury during normothermic reperfusion, ensure the safe implementation of NMP, and improve kidney quality. This review discusses the pathophysiological alterations in the vasculature, metabolism, oxygenation, electrolyte balance, and acid-base homeostasis of deceased-donor kidneys and delineates renoprotective strategies and therapeutic interventions to mitigate renal injury and improve kidney quality during NMP.

The molecular mechanisms and potential drug targets of ferroptosis in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI), caused by the initial interruption and subsequent restoration of coronary artery blood, results in further damage to cardiac function, affecting the prognosis of patients with acute myocardial infarction. Ferroptosis is an iron-dependent, superoxide-driven, non-apoptotic form of regulated cell death that is involved in the pathogenesis of MIRI. Ferroptosis is characterized by the accumulation of lipid peroxides (LOOH) and redox disequilibrium. Free iron ions can induce lipid oxidative stress as a substrate of the Fenton reaction and lipoxygenase (LOX) and participate in the inactivation of a variety of lipid antioxidants including CoQ10 and GPX4, destroying the redox balance and causing cell death. The metabolism of amino acid, iron, and lipids, including associated pathways, is considered as a specific hallmark of ferroptosis. This review systematically summarizes the latest research progress on the mechanisms of ferroptosis and discusses and analyzes the therapeutic approaches targeting ferroptosis to alleviate MIRI.

CKLF1, transcriptionally activated by FOXC1, promotes hypoxia/reoxygenation‑induced oxidative stress and inflammation in H9c2 cells by NLRP3 inflammasome activation

Myocardial ischemia/reperfusion (I/R) injury is a clinical challenge in the treatment of ischemic heart disease. The present study aimed to establish a hypoxia/reoxygenation (H/R)-induced H9c2 cell model to explore the role and mechanism of chemokine-like factor 1 (CKLF1) in myocardial I/R injury. First, CKLF1 expression was measured in H/R-induced H9c2 cells by reverse transcription-quantitative PCR and western blotting. Subsequently, after CKLF1 silencing, cell viability and apoptosis were evaluated by Cell Counting Kit-8 assay and flow cytometry. In addition, 2,7-dichlorodihydrofluorescein diacetate staining was used to assess the levels of cellular reactive oxygen species. Additionally, the levels of superoxide dismutase, glutathione peroxidase and malondialdehyde, and the contents of inflammatory factors IL-6, IL-1β and TNF-α were detected using corresponding commercially available kits. Western blotting was used to examine the expression levels of proteins involved in the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome. The JASPAR database predicted that forkhead box protein C1 (FOXC1) would bind to the CKLF1 promoter region, and dual luciferase and chromatin immunoprecipitation assays were performed to verify it. Subsequently, FOXC1 overexpression and CKLF1 silencing were used to clarify the regulatory mechanism of FOXC1 on CKLF1 in H/R-induced H9c2 cells. The results revealed that CKLF1 expression was markedly enhanced in H/R-stimulated H9c2 cells. CKLF1 knockdown enhanced the viability and inhibited the apoptosis of H9c2 cells exposed to H/R. Moreover, the oxidative stress and inflammation induced by H/R were alleviated following CKLF1 silencing. CKLF1 knockdown also inhibited NLRP3 inflammasome activation. Furthermore, FOXC1 bound to the CKLF1 promoter region to upregulate CKLF1 expression, and FOXC1 overexpression alleviated the effects of CKLF1 knockdown on H9c2 cell damage induced by H/R via activation of the NLRP3 inflammasome. In conclusion, CKLF1 transcriptionally activated by FOXC1 may promote H/R-induced oxidative stress and inflammation in H9c2 cells via NLRP3 inflammasome activation.

Redox differences between rat neonatal and adult cardiomyocytes under hypoxia

It is generally accepted that oxidative stress plays a key role in the development of ischemia-reperfusion injury in ischemic heart disease. However, the mechanisms how reactive oxygen species trigger cellular damage are not fully understood. Our study investigates redox state and highly reactive substances within neonatal and adult cardiomyocytes under hypoxia conditions. We have found that hypoxia induced an increase in H2O2 production in adult cardiomyocytes, while neonatal cardiomyocytes experienced a decrease in H2O2 levels. This finding correlates with our observation of the difference between the electron transport chain (ETC) properties and mitochondria amount in adult and neonatal cells. We demonstrated that in adult cardiomyocytes hypoxia caused the significant increase in the ETC loading with electrons compared to normoxia. On the contrary, in neonatal cardiomyocytes ETC loading with electrons was similar under both normoxic and hypoxic conditions that could be due to ETC non-functional state and the absence of the electrons transfer to O2 under normoxia. In addition to the variations in H2O2 production, we also noted consistent pH dynamics under hypoxic conditions. Notably, the pH levels exhibited a similar decrease in both cell types, thus, acidosis is a more universal cellular response to hypoxia. We also demonstrated that the amount of mitochondria and the levels of cardiac isoforms of troponin I, troponin T, myoglobin and GAPDH were significantly higher in adult cardiomyocytes compared to neonatal ones. Remarkably, we found out that under hypoxia, the levels of cardiac isoforms of troponin T, myoglobin, and GAPDH were elevated in adult cardiomyocytes, while their level in neonatal cells remained unchanged. Obtained data contribute to the understanding of the mechanisms of neonatal cardiomyocytes' resistance to hypoxia and the ability to maintain the metabolic homeostasis in contrast to adult ones.

Nicotine Diminishes Alpha2-Adrenergic Receptor-Dependent Protection Against Oxidative Stress in H9c2 Cardiomyocytes

Introduction

Nicotine is a major component of cigarette smoke with various detrimental cardiovascular effects, including increased oxidative stress in the heart. Agonism of α2-adrenergic receptors (ARs), such as with dexmedetomidine, has been documented to exert cardioprotective effects against oxidative stress and related apoptosis and necroptosis. α2-ARs are membrane-residing G protein-coupled receptors (GPCRs) that primarily activate Gi/o proteins. They are also subjected to GPCR-kinase (GRK)-2-dependent desensitization, which entails phosphorylation of the agonist-activated receptor by GRK2 to induce its decoupling from G proteins, thus terminating α2AR-mediated G protein signaling.

Objective

In the present study, we sought to examine the effects of nicotine on α2AR signaling and effects in H9c2 cardiomyocytes exposed to H2O2 to induce oxidative cellular damage.

Methods and Results

As expected, treatment of H9c2 cardiomyocytes with H2O2 significantly decreased cell viability and increased oxidative stress, as assessed by reactive oxygen species (ROS)-associated fluorescence levels (DCF assay) and superoxide dismutase activity. Both H2O2 effects were partly rescued by α2AR activation with brimonidine in control cardiomyocytes but not in cells pretreated with nicotine for 24 hours, in which brimonidine was unable to reduce H2O2-induced cell death and oxidative stress. This was due to severe α2AR desensitization, manifested as very low Gi protein activation by brimonidine, and accompanied by GRK2 upregulation in nicotine-treated cardiomyocytes. Finally, pharmacological inhibition of adenylyl cyclase (AC) blocked H2O2-dependent oxidative damage in nicotine-pretreated H9c2 cardiomyocytes, indicating that α2AR activation protects against oxidative injury via its classic coupling to Gai-mediated AC inhibition.

Discussion/Conclusions

Nicotine can negate the cardioprotective effects of α2AR agonists against oxidative injury, which may have important implications for patients treated with this class of drugs that are chronic tobacco smokers.

Mechanistic Implications of GSK and CREB Crosstalk in Ischemia Injury

Ischemia-reperfusion (IR) injury is a damage to an organ when the blood supply is less than the demand required for normal functioning, leading to exacerbation of cellular dysfunction and death. IR injury occurs in different organs like the kidney, liver, heart, brain, etc., and may not only involve the ischemic organ but also cause systemic damage to distant organs. Oxygen-glucose deprivation in cells causes oxidative stress, calcium overloading, inflammation, and apoptosis. CREB is an essential integrator of the body's various physiological systems, and it is widely accepted that dysfunction of CREB signaling is involved in many diseases, including ischemia-reperfusion injury. The activation of CREB can provide life to a cell and increase the cell's survival after ischemia. Hence, GSK/CREB signaling pathway can provide significant protection to cells of different organs after ischemia and emerges as a futuristic strategy for managing ischemia-reperfusion injury. Different signaling pathways such as MAPK/ERK, TLR4/MyD88, RISK, Nrf2, and NF-κB, get altered during IR injury by the modulation of GSK-3 and CREB (cyclic AMP response element (CRE)-binding protein). GSK-3 (protein kinase B) and CREB are the downstream targets for fulfilling the roles of various signaling pathways. Calcium overloading during ischemia increases the expression of calcium-calmodulin-dependent protein kinase (CaMK), which subsequently activates CREB-mediated transcription, thus promoting the survival of cells. Furthermore, this review highlights the crosstalk between GSK-3 and CREB, promoting survival and rendering the cells resistant to subsequent severe ischemia.

Biomaterials-mediated targeted therapeutics of myocardial ischemia-reperfusion injury

Reperfusion therapy is widely used to treat acute myocardial infarction. However, its efficacy is limited by myocardial ischemia-reperfusion injury (MIRI), which occurs paradoxically due to the reperfusion therapy and contributes to the high mortality rate of acute myocardial infarction. Systemic administration of drugs, such as antioxidant and anti-inflammatory agents, to reduce MIRI is often ineffective due to the inadequate release at the pathological sites. Functional biomaterials are being developed to optimize the use of drugs by improving their targetability and bioavailability and reducing side effects, such as gastrointestinal irritation, thrombocytopenia, and liver damage. This review provides an overview of controlled drug delivery biomaterials for treating MIRI by triggering antioxidation, calcium ion overload inhibition, and/or inflammation regulation mechanisms and discusses the challenges and potential applications of these treatments clinically.

Coronary No-Reflow after Primary Percutaneous Coronary Intervention-Current Knowledge on Pathophysiology, Diagnosis, Clinical Impact and Therapy

Coronary no-reflow (CNR) is a frequent phenomenon that develops in patients with ST-segment elevation myocardial infarction (STEMI) following reperfusion therapy. CNR is highly dynamic, develops gradually (over hours) and persists for days to weeks after reperfusion. Microvascular obstruction (MVO) developing as a consequence of myocardial ischemia, distal embolization and reperfusion-related injury is the main pathophysiological mechanism of CNR. The frequency of CNR or MVO after primary PCI differs widely depending on the sensitivity of the tools used for diagnosis and timing of examination. Coronary angiography is readily available and most convenient to diagnose CNR but it is highly conservative and underestimates the true frequency of CNR. Cardiac magnetic resonance (CMR) imaging is the most sensitive method to diagnose MVO and CNR that provides information on the presence, localization and extent of MVO. CMR imaging detects intramyocardial hemorrhage and accurately estimates the infarct size. MVO and CNR markedly negate the benefits of reperfusion therapy and contribute to poor clinical outcomes including adverse remodeling of left ventricle, worsening or new congestive heart failure and reduced survival. Despite extensive research and the use of therapies that target almost all known pathophysiological mechanisms of CNR, no therapy has been found that prevents or reverses CNR and provides consistent clinical benefit in patients with STEMI undergoing reperfusion. Currently, the prevention or alleviation of MVO and CNR remain unmet goals in the therapy of STEMI that continue to be under intense research.

Thiopental sodium attenuates hypoxia/reoxygenation-induced injury in osteoblasts by modulating AKT signaling

Thiopental sodium (TPTS) is a barbiturate general anesthetic, while its effects on hypoxia/reoxygenation (H/R)-induced injury are still unclear. This study aimed to investigate whether TPTS exerts protective effects against the H/R-induced osteoblast cell injury and explore the underlying mechanisms. Osteoblast cell injury model was induced by the H/R condition, which was treated with or without TPTS. Cell viability and lactate dehydrogenase (LDH) release were determined by the corresponding commercial kits. The levels of oxidative stress were determined in the experimental groups. Cell apoptosis and Caspase-3 activities were determined by propidium iodide staining and substrate-based assay, respectively. Western blotting and qRT-PCR were performed to measure the mRNA and protein levels, respectively. Treatment with TPTS was able to increase cell viability and reduce LDH release in H/R-induced osteoblasts. Additionally, TPTS regulated oxidative stress in H/R-induced osteoblasts by suppressing malondialdehyde (MDA) and reactive oxygen species (ROS) as well as boosting superoxide dismutase (SOD). TPTS was able to suppress cell apoptosis by suppressing Caspase-3 activity and cleavage. TPTS exerted protective effects against cell injury and apoptosis induced by the H/R conditions, which were associated with its regulation of Akt signaling. Moreover, TPTS induced osteoblast differentiation under the H/R condition. In summary, TPTS attenuates H/R-induced injury in osteoblasts by regulating AKT signaling.

Effects of Taraxerol on Oxidative and Inflammatory Mediators in Isoproterenol-Induced Cardiotoxicity in an Animal Model

Myocardial infarction (MI) continues to be an important issue in healthcare systems worldwide, leading to high rates of morbidity and mortality. Despite ongoing efforts towards the development of preventive measures and treatments, addressing the challenges posed by MI remains difficult both in developed and developing countries. However, researchers recently investigated the potential cardioprotective effects of taraxerol utilizing an isoproterenol (ISO)-induced cardiotoxicity model among Sprague Dawley rats. Specifically, subcutaneous tissue injections consisting of 5.25 mg/kg or 8.5 mg/kg ISO were administered over two consecutive days as stimuli to induce cardiac injury. To investigate the possibility of preventing damage caused by ISO-induced cardiotoxicity by taraxerol treatment, five groups were formed: a normal control group (1% Tween 80), an ISO control group, an amlodipine group administered 5 mg/kg/day, and various doses of taraxerol. The study results showed that treatment significantly reduced cardiac marker enzymes. Additionally, pretreatment with taraxerol increased myocardial activity in SOD and GPx, leading to significant reductions in serum CK-MB levels along with MDA, TNF-α, and IL-6. Further histopathological analysis supported these observations, as treated animals had less cellular infiltration compared to untreated ones. These multifaceted findings suggest that oral administration of taraxerol could potentially protect hearts from ISO-caused damage by increasing endogenous antioxidant concentrations while decreasing pro-inflammatory cytokines.

Cardioprotective potential of vanillic acid

Nowadays, cardiovascular diseases (CVDs) are a global threat to public health, accounting for almost one-third of all deaths worldwide. One of the key mechanistic pathways contributing to the development of CVDs, including cardiotoxicity (CTX) and myocardial ischaemia-reperfusion injury (MIRI) is oxidative stress (OS). Increased generation of reactive oxygen species (ROS) is closely associated with decreased antioxidant capacity and mitochondrial dysfunction. Currently, despite the availability of modern pharmaceuticals, dietary-derived antioxidants are becoming more popular in developed societies to delay the progression of CVDs. One of the antioxidants derived from herbs, fruits, whole grains, juices, beers, and wines is vanillic acid (VA), which, as a phenolic compound, possesses different therapeutic properties, including cardioprotective. Based on experimental evidence, VA improves mitochondrial function as a result of the reduction in ROS production, aggravates antioxidative status, scavenges free radicals, and reduces levels of lipid peroxidation, thereby decreasing cardiac dysfunction, in particular CTX and MIRI. Considering the role of OS in the pathophysiology of CVDs, the purpose of this study is to comprehensively address recent evidence on the antioxidant importance of VA in the cardiovascular system.

Dexmedetomidine attenuates myocardial ischemia-reperfusion injury via inhibiting ferroptosis by the cAMP/PKA/CREB pathway

This study is to investigate the effects of dexmedetomidine on myocardial ischemia-reperfusion (I/R) injury and its molecular mechanisms. H9c2 cell injury model was constructed by the hypoxia/normoxia (H/R) conditions. Besides, cAMP response element-binding protein (CREB) overexpression and knockdown cell lines were constructed. Cell viability was determined by cell-counting kit 8. Biochemical assays were used to detect oxidative stress-related biomarkers, cell apoptosis, and ferroptosis-related markers. Our results showed that dexmedetomidine's protective effects on H/R-induced cell damage were reversed by the inhibition of protein kinase A (PKA), CREB, and extracellular signal regulated kinase 1/2 (ERK1/2). Treatment of dexmedetomidine ameliorated oxidative stress in the cardiomyocytes induced by H/R, whereas inhibition of PKA, CREB, or ERK1/2 reversed these protective effects. Cell death including cell necrosis, apoptosis, and ferroptosis was found in the cells under H/R insult. Interestingly, targeting CREB ameliorated ferroptosis and oxidative stress in these cells. In conclusion, dexmedetomidine attenuates myocardial I/R injury by suppressing ferroptosis through the cAMP/PKA/CREB signaling pathway.

Microalgae as a Source of Valuable Phenolic Compounds and Carotenoids

Microalgae are photosynthetic, eukaryotic organisms that are widely used in the industry as cell factories to produce valuable substances, such as fatty acids (polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), sterols (sitosterol), recombinant therapeutic proteins, carbohydrates, vitamins, phenolic compounds (gallic acid, quercetin), and pigments (β-carotene, astaxanthin, lutein). Phenolic compounds and carotenoids, including those extracted from microalgae, possess beneficial bioactivities such as antioxidant capacity, antimicrobial and immunomodulatory activities, and direct health-promoting effects, which may alleviate oxidative stress and age-related diseases, including cardiovascular diseases or diabetes. The production of valuable microalgal metabolites can be modified by using abiotic stressors, such as light, salinity, nutrient availability, and xenobiotics (for instance, phytohormones).

Device-Based Approaches Targeting Cardioprotection in Myocardial Infarction: The Expanding Armamentarium of Innovative Strategies

Coronary reperfusion therapy has played a pivotal role for reducing mortality and heart failure after acute myocardial infarction. Although several adjunctive approaches have been studied for reducing infarct size further, both ischemia-reperfusion injury and microvascular obstruction are still major contributors to both early and late clinical events after acute myocardial infarction. The progress in the field of cardioprotection has found several promising proof-of-concept preclinical studies. However, translation from bench to bedside has not been very successful. This comprehensive review discusses the importance of infarct size as a driver of clinical outcomes post-acute myocardial infarction and summarizes recent novel device-based approaches for infarct size reduction. Device-based interventions including mechanical cardiac unloading, myocardial cooling, coronary sinus interventions, supersaturated oxygen therapy, and vagal stimulation are discussed. Many of these approaches can modify ischemic myocardial biology before reperfusion and offer unique opportunities to target ischemia-reperfusion injury.

Mechanical characterization of isolated mitochondria under conditions of oxidative stress

Mechanical properties have been proven to be a pivotal parameter to enhance our understanding of living systems. While research during the last decades focused on cells and tissues, little is known about the role of organelle mechanics in cell function. Here, mitochondria are of specific interest due to their involvement in numerous physiological and pathological processes, e.g., in the production and homeostasis of reactive oxygen species (ROS). Using real-time fluorescence and deformability cytometry, we present a microfluidic technology that is capable to determine the mechanical properties of individual mitochondria at a throughput exceeding 100 organelles per second. Our data on several thousands of viable mitochondria isolated from rat C6 glial cells yield a homogenous population with a median deformation that scales with the applied hydrodynamic stress. In two proof-of-principle studies, we investigated the impact of exogenously and endogenously produced ROS on mitochondria mechanics. Exposing C6 cells to hydrogen peroxide (H₂O₂) triggers superoxide production and leads to a reduction in mitochondria size while deformation is increased. In a second study, we focused on the knockout of tafazzin, which has been associated with impaired remodeling of the mitochondrial membrane and elevated levels of ROS. Interestingly, our results reveal the same mechanical alterations as observed after the exposure to H₂O₂, which points to a unified biophysical mechanism of how mitochondria respond to the presence of oxidative stress. In summary, we introduce high-throughput mechanical phenotyping into the field of organelle biology with potential applications for understanding sub-cellular dynamics that have not been accessible before.

Bioinformatics analysis identifies ferroptosis‑related genes in the regulatory mechanism of myocardial infarction

Since ferroptosis is considered to be a notable cause of cardiomyocyte death, inhibiting ferroptosis has become a novel strategy in reducing cardiac cell death and improving cardiopathic conditions. Therefore, the aim of the present study was to search for ferroptosis-related hub genes and determine their diagnostic value in myocardial infarction (MI) to aid in the diagnosis and treatment of the disease. A total of 10,286 DEGs were identified, including 6,822 upregulated and 3.464 downregulated genes in patients with MI compared with healthy controls. After overlapping with ferroptosis-related genes, 128 ferroptosis-related DEGs were obtained. WGCNA successfully identified a further eight functional modules, from which the blue module had the strongest correlation with MI. Blue module genes and ferroptosis-related differentially expressed genes were overlapped to obtain 20 ferroptosis-related genes associated with MI. Go and KEGG analysis showed that these genes were mainly enriched in cellular response to chemical stress, trans complex, transferring, phosphorus-containing groups, protein serine/threonine kinase activity, FoxO signaling pathway. Hub genes were obtained from 20 ferroptosis-related genes through the PPI network. The expression of hub genes was found to be down-regulated in the MI group. Finally, the miRNAs-hub genes and TFs-hub genes networks were constructed. The GSE141512 dataset and the use of RT-qPCR assays on patient blood samples were used to confirm these results. The results showed that ATM, PIK3CA, MAPK8, KRAS and SIRT1 may play key roles in the development of MI, and could therefore be novel markers or targets for the diagnosis or treatment of MI.

Anti-ischemic effect of Tamarindus indica L. seed extract against myocardial hypoxic injury

Background: Ischemic heart disease is a leading cause of death in patients with cardiovascular disease. Natural products containing high antioxidant activity have been used as an alternative therapy to improve the living conditions of patients. In this study, we examine the protective effect of tamarind seed (TS) on myocardial hypoxic injury. Methods: The hypoxia model was mimicked by mineral oil overlayed on H9c2 cardiomyoblasts for 4 h. TS extract was pretreated and administered during the hypoxic condition. Radical scavenging activity of TS extract was measured and exhibited very potent antioxidant activities on 2,2-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. Results: TS extract at a concentration of 10 µg/ml significantly reversed the effect of hypoxia-induced cell death and intracellular reactive oxygen species (ROS) production. We also observed hypoxia-induced over-expression of both inflammatory cytokine mRNA and activation of cellular apoptosis. Pretreatment of TS extract significantly reduced hypoxia-induced HIF-1a and pro-inflammatory cytokine production, IL-1b and IL-6. The Western blot analysis for apoptotic regulatory molecules, caspase 3, caspase 8 and Bax proteins, also showed hypoxia injury reversal by TS extract treatment. Conclusions: The results suggest that the anti-ischemic effect of TS extract protects against hypoxia-induced injury and has potential to be an effective alternative therapy for ischemic heart disease and oxidative-damage related disease.

Progress in Stimuli-Responsive Biomaterials for Treating Cardiovascular and Cerebrovascular Diseases

Cardiovascular and cerebrovascular diseases (CCVDs) describe abnormal vascular system conditions affecting the brain and heart. Among these, ischemic heart disease and ischemic stroke are the leading causes of death worldwide, resulting in 16% and 11% of deaths globally. Although several therapeutic approaches are presented over the years, the continuously increasing mortality rates suggest the need for more advanced strategies for their treatment. One of these strategies lies in the use of stimuli-responsive biomaterials. These "smart" biomaterials can specifically target the diseased tissue, and after "reading" the altered environmental cues, they can respond by altering their physicochemical properties and/or their morphology. In this review, the progress in the field of stimuli-responsive biomaterials for CCVDs in the last five years, aiming at highlighting their potential as early-stage therapeutics in the preclinical scenery, is described.

Exercise-induced signaling pathways to counteracting cardiac apoptotic processes

Cardiovascular diseases are the most common cause of death in the world. One of the major causes of cardiac death is excessive apoptosis. However, multiple pathways through moderate exercise can reduce myocardial apoptosis. After moderate exercise, the expression of anti-apoptotic proteins such as IGF-1, IGF-1R, p-PI3K, p-Akt, ERK-1/2, SIRT3, PGC-1α, and Bcl-2 increases in the heart. While apoptotic proteins such as PTEN, PHLPP-1, GSK-3, JNK, P38MAPK, and FOXO are reduced in the heart. Exercise-induced mechanical stress activates the β and α5 integrins and subsequently, focal adhesion kinase phosphorylation activates the Akt/mTORC1 and ERK-1/2 pathways, leading to an anti-apoptotic response. One of the reasons for the decrease in exercise-induced apoptosis is the decrease in Fas-ligand protein, Fas-death receptor, TNF-α receptor, Fas-associated death domain (FADD), caspase-8, and caspase-3. In addition, after exercise mitochondrial-dependent apoptotic factors such as Bid, t-Bid, Bad, p-Bad, Bak, cytochrome c, and caspase-9 are reduced. These changes lead to a reduction in oxidative damage, a reduction in infarct size, a reduction in cardiac apoptosis, and an increase in myocardial function. After exercising in the heart, the levels of RhoA, ROCK1, Rac1, and ROCK2 decrease, while the levels of PKCε, PKCδ, and PKCɑ are activated to regulate calcium and prevent mPTP perforation. Exercise has an anti-apoptotic effect on heart failure by increasing the PKA-Akt-eNOS and FSTL1-USP10-Notch1 pathways, reducing the negative effects of CaMKIIδ, and increasing the calcineurin/NFAT pathway. Exercise plays a protective role in the heart by increasing HSP20, HSP27, HSP40, HSP70, HSP72, and HSP90 along with increasing JAK2 and STAT3 phosphorylation. However, research on exercise and factors such as Pim-1, Notch, and FAK in cardiac apoptosis is scarce, so further research is needed. Future research is recommended to discover more anti-apoptotic pathways. It is also recommended to study the synergistic effect of exercise with gene therapy, dietary supplements, and cell therapy for future research.

Role of Oxidative Stress in Cardiac Dysfunction and Subcellular Defects Due to Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury is well-known to be associated with impaired cardiac function, massive arrhythmias, marked alterations in cardiac metabolism and irreversible ultrastructural changes in the heart. Two major mechanisms namely oxidative stress and intracellular Ca²⁺-overload are considered to explain I/R-induced injury to the heart. However, it is becoming apparent that oxidative stress is the most critical pathogenic factor because it produces myocardial abnormalities directly or indirectly for the occurrence of cardiac damage. Furthermore, I/R injury has been shown to generate oxidative stress by promoting the formation of different reactive oxygen species due to defects in mitochondrial function and depressions in both endogenous antioxidant levels as well as regulatory antioxidative defense systems. It has also been demonstrated to adversely affect a wide variety of metabolic pathways and targets in cardiomyocytes, various resident structures in myocardial interstitium, as well as circulating neutrophils and leukocytes. These I/R-induced alterations in addition to myocardial inflammation may cause cell death, fibrosis, inflammation, Ca²⁺-handling abnormalities, activation of proteases and phospholipases, as well as subcellular remodeling and depletion of energy stores in the heart. Analysis of results from isolated hearts perfused with or without some antioxidant treatments before subjecting to I/R injury has indicated that cardiac dysfunction is associated with the development of oxidative stress, intracellular Ca²⁺-overload and protease activation. In addition, changes in the sarcolemma and sarcoplasmic reticulum Ca²⁺-handling, mitochondrial oxidative phosphorylation as well as myofibrillar Ca²⁺-ATPase activities in I/R hearts were attenuated by pretreatment with antioxidants. The I/R-induced alterations in cardiac function were simulated upon perfusing the hearts with oxyradical generating system or oxidant. These observations support the view that oxidative stress may be intimately involved in inducing intracellular Ca²⁺-overload, protease activation, subcellular remodeling, and cardiac dysfunction as a consequence of I/R injury to the heart.

Lupeol Alleviates Myocardial Ischemia-Reperfusion Injury in Rats by Regulating NF-[Formula: see text]B and Nrf2 Pathways

Cardiovascular disease is a global health problem. Previous studies revealed that it involves acute myocardial infarction and ischemia-reperfusion (I/R) injury. The mechanism of myocardial I/R injury is complex. But recognizing its mechanisms will bring important clinical significance. Lupeol is widely found in Chinese medicinal herbs and has been shown to have a variety of bio-activities. However, the pharmacological action of lupeol in the progress of myocardial ischemia-reperfusion injury (MIRI) is unclear. This study used a rat myocardial I/R model and the morphological changes in myocardium were determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining. The expression levels of IL-10, IL-1[Formula: see text], TNF-[Formula: see text], and IL-6 were assessed by quantitative real-time PCR (qRT-PCR) and ELISA. The expression levels of MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase (LDH) level and inflammatory cytokines were quantified using ELISA. The cellular apoptotic rate was determined by TUNEL staining. The findings showed that lupeol significantly decreased myocardial infarction after I/R and ameliorated I/R-induced myocardial inflammation, apoptosis, and oxidative stress. Furthermore, our results suggested that lupeol protected against MIRI-induced myocardial infarction through modulation of NF-[Formula: see text]B and Nrf2 signaling pathways. In summary, this study first clarified the cardioprotective effects of lupeol against I/R-induced myocardial infarction in rats, which could be due to its anti-oxidant, anti-inflammatory, and anti-apoptotic activities. Our study also highlighted a mechanism of NF-[Formula: see text]B and Nrf2 signaling, through which lupeol could be a promising agent in protecting against I/R-induced myocardial infarction.

Inhibition of miR-182-5p attenuates ROS and protects against myocardial ischemia-reperfusion injury by targeting STK17A

Reperfusion therapy for acute myocardial infarction inevitably leads to ischemia-reperfusion (I/R) injury. A number of miRNAs are reported to be involved in I/R injury. This study aims to investigate the role and underlying mechanism of miR-182-5p in I/R injury. An in vivo model of I/R-induced rat myocardial injury and an in vitro model of H/R H9c2 cells were established to investigate the role and mechanism of miR-182-5p in I/R injury. The myocardial infarct size was determined by TTC staining. The serum CK-MB level was determined by ELISA kit. The miR-182-5p inhibitors or mimics were used to down-regulate or up-regulate its expression. The apoptosis and ROS were detected by flow cytometry. The expression of the proteins was detected by western blot. The binding of STK17A and miR-182-5p was validated by dual-luciferase reporter assay. The miR-182-5p was confirmed to be highly expressed in I/R injury rats and H/R H9c2 cells. Inhibition of miR-182-5p significantly reduced the infarct size and decreased the serum CK-MB level of I/R rats, and significantly reduced the ROS level but increased the level of MnSOD and catalase. While, an opposite effect was observed in the miR-182-5p mimics group. Furthermore, our results suggested that miR-182-5p targeted STK17A, and TK17A knockdown significantly increased the apoptotic rate and ROS level. The inhibitory effect of miR-182-5p inhibitors on apoptotic rate, ROS, MnSOD, and catalase levels were abrogated by siSTK17A. These results indicate that miR-182-5p regulates the apoptosis and ROS and protects against myocardial I/R injury by targeting STK17A.

Asiatic Acid Alleviates Myocardial Ischemia-Reperfusion Injury by Inhibiting the ROS-Mediated Mitochondria-Dependent Apoptosis Pathway

Myocardial ischemia-reperfusion injury (MIRI) is a major cause of heart failure in patients with coronary heart disease (CHD). Mitochondrial dysfunction is the crucial factor of MIRI; oxidative stress caused by mitochondrial reactive oxygen species (ROS) aggravates myocardial cell damage through the mitochondria-dependent apoptosis pathway. Asiatic acid (AA) is a type of pentacyclic triterpene compound purified from the traditional Chinese medicine Centella asiatica, and its protective pharmacological activities have been reported in various disease models. This study is aimed at investigating the protective effects of AA and the underlying mechanisms in MIRI. To achieve this goal, an animal model of MIRI in vivo and a cell model of oxygen-glucose deprivation/reperfusion (OGD/R) in vitro were established. The results show that AA exerts a protective effect on MIRI by improving cardiac function and reducing cardiomyocyte damage. Due to its antioxidant properties, AA alleviates mitochondrial oxidative stress, as evidenced by the stable mitochondrial structure, maintained mitochondrial membrane potential (MMP), and reduced ROS generation, otherwise due to its antiapoptotic properties. AA inhibits the mitogen-activated protein kinase (MAPK)/mitochondria-dependent apoptosis pathway, as evidenced by the limited phosphorylation of p38-MAPK and JNK-MAPK, balanced proportion of Bcl-2/Bax, reduced cytochrome c release, inhibition of caspase cascade, and reduced apoptosis. In conclusion, our study confirms that AA exerts cardiac-protective effects by regulating ROS-induced oxidative stress via the MAPK/mitochondria-dependent apoptosis pathway; the results provide new evidence that AA may represent a potential treatment for CHD patients.

A Novel Insight Into the Fate of Cardiomyocytes in Ischemia-Reperfusion Injury: From Iron Metabolism to Ferroptosis

Ischemia-reperfusion injury (IRI), critically involved in the pathology of reperfusion therapy for myocardial infarction, is closely related to oxidative stress the inflammatory response, and disturbances in energy metabolism. Emerging evidence shows that metabolic imbalances of iron participate in the pathophysiological process of cardiomyocyte IRI [also termed as myocardial ischemia-reperfusion injury (MIRI)]. Iron is an essential mineral required for vital physiological functions, including cellular respiration, lipid and oxygen metabolism, and protein synthesis. Nevertheless, cardiomyocyte homeostasis and viability are inclined to be jeopardized by iron-induced toxicity under pathological conditions, which is defined as ferroptosis. Upon the occurrence of IRI, excessive iron is transported into cells that drive cardiomyocytes more vulnerable to ferroptosis by the accumulation of reactive oxygen species (ROS) through Fenton reaction and Haber–Weiss reaction. The increased ROS production in ferroptosis correspondingly leads cardiomyocytes to become more sensitive to oxidative stress under the exposure of excess iron. Therefore, ferroptosis might play an important role in the pathogenic progression of MIRI, and precisely targeting ferroptosis mechanisms may be a promising therapeutic option to revert myocardial remodeling. Notably, targeting inhibitors are expected to prevent MIRI deterioration by suppressing cardiomyocyte ferroptosis. Here, we review the pathophysiological alterations from iron homeostasis to ferroptosis together with potential pathways regarding ferroptosis secondary to cardiovascular IRI. We also provide a comprehensive analysis of ferroptosis inhibitors and initiators, as well as regulatory genes involved in the setting of MIRI.

[Myorenal syndrome in forensic practice: molecular aspects of etiology and pathogenesis]

The objective of the study is to analyze the publications on biochemical aspects of myorenal syndrome (crush-syndrome) pathogenesis. Factors of trauma and other etiologies significant in terms of forensic practice that cause muscle tissue destruction are presented. Molecular processes in rhabdomyolysis and subsequent renal damage, the establishment of the sequence of which is important for forensic medicine, are outlined. The study results will improve our understanding of the of myorenal syndrome pathophysiology, its biochemical features, and optimize methods for its forensic diagnosis.

MicroRNA-214 in Health and Disease

MicroRNAs (miRNAs) are endogenously expressed, non-coding RNA molecules that mediate the post-transcriptional repression and degradation of mRNAs by targeting their 3′ untranslated region (3′-UTR). Thousands of miRNAs have been identified since their first discovery in 1993, and miR-214 was first reported to promote apoptosis in HeLa cells. Presently, miR-214 is implicated in an extensive range of conditions such as cardiovascular diseases, cancers, bone formation and cell differentiation. MiR-214 has shown pleiotropic roles in contributing to the progression of diseases such as gastric and lung cancers but may also confer cardioprotection against excessive fibrosis and oxidative damage. These contrasting functions are achieved through the diverse cast of miR-214 targets. Through silencing or overexpressing miR-214, the detrimental effects can be attenuated, and the beneficial effects promoted in order to improve health outcomes. Therefore, discovering novel miR-214 targets and understanding how miR-214 is dysregulated in human diseases may eventually lead to miRNA-based therapies. MiR-214 has also shown promise as a diagnostic biomarker in identifying breast cancer and coronary artery disease. This review provides an up-to-date discussion of miR-214 literature by describing relevant roles in health and disease, areas of disagreement, and the future direction of the field.

Ferroptosis: Opportunities and Challenges in Myocardial Ischemia-Reperfusion Injury

Ferroptosis is a newly discovered form of regulated cell death dependent on iron and reactive oxygen species (ROS). It directly or indirectly affects the activity of glutathione peroxidases (GPXs) under the induction of small molecules, causing membrane lipid peroxidation due to redox imbalances and excessive ROS accumulation, damaging the integrity of cell membranes. Ferroptosis is mainly characterized by mitochondrial shrinkage, increased density of bilayer membranes, and the accumulation of lipid peroxidation. Myocardial ischemia-reperfusion injury (MIRI) is an unavoidable risk event for acute myocardial infarction. Ferroptosis is closely associated with MIRI, and this relationship is discussed in detail here. This review systematically summarizes the process of ferroptosis and the latest research progress on the role of ferroptosis in MIRI to provide new ideas for the prevention and treatment of MIRI.

Bilirubin Nanoparticles Protect Against Cardiac Ischemia/Reperfusion Injury in Mice

Background

Ischemia/reperfusion (I/R) injury causes overproduction of reactive oxygen species, which are the major culprits of oxidative stress that leads to inflammation, apoptosis, myocardial damage, and dysfunction. Bilirubin acts as a potent endogenous antioxidant that is capable of scavenging various reactive oxygen species. We have previously generated bilirubin nanoparticles (BRNPs) consisting of polyethylene glycol–conjugated bilirubin. In this study, we examined the therapeutic effects of BRNPs on myocardial I/R injury in mice.

Methods and Results

In vivo imaging using fluorophore encapsulated BRNPs showed BRNPs preferentially targeted to the site of I/R injury in the heart. Cardiac I/R surgery was performed by first ligating the left anterior descending coronary artery. After 45 minutes, reperfusion was achieved by releasing the ligation. BRNPs were administered intraperitoneally at 5 minutes before and 24 hours after reperfusion. Mice that received BRNPs showed significant improvements in their cardiac output, assessed by echocardiogram and pressure volume loop measurements, compared with the ones that received vehicle treatment. BRNPs treatment also significantly reduced the myocardial infarct size in mice that underwent cardiac I/R, compared with the vehicle‐treatment group. In addition, BRNPs effectively suppressed reactive oxygen species and proinflammatory factor levels, as well as the amount of cardiac apoptosis.

Conclusions

Taken together, BRNPs could exert their therapeutic effects on cardiac I/R injury through attenuation of oxidative stress, apoptosis, and inflammation, providing a novel therapeutic modality for myocardial I/R injury.

Pectin/chitosan/tripolyphosphate encapsulation protects the rat lung from fibrosis and apoptosis induced by paraquat inhalation

BACKGROUND

Paraquat poisoning leads to lung injury and pulmonary fibrosis. The effect of paraquat encapsulation by previously described Pectin/Chitosan/Tripolyphosphate nanoparticles on its pulmonary toxicity was investigated in present study in a rat model of poison inhalation.

MATERIAL AND METHOD

The rats inhaled nebulized different formulation of paraquat (n = 5) for 30 min in various experimental groups. Lung injury and fibrosis scores, Lung tissue enzymatic activities, apoptosis markers were determined compared among groups.

RESULTS

Encapsulation of paraquat significantly rescued both lung injury and fibrosis scores. Lung MDA level was reduced by encapsulation. Paraquat poisoning led to lung tissue apoptosis as was evidenced by higher Caspase-3 and Bax/Bcl2 expressions in rats subjected to paraquat inhalation instead of normal saline or free nanoparticles. Again, nanoencapsulation reduced these apoptosis markers significantly. Alpha-SMA expression was also reduced by encapsulation. Nanoparticles per se have no or little toxicity as was evidenced by inflammatory and apoptotic markers and histological scores.

CONCLUSION

In a rat model of inhalation toxicity of paraquat, loading of this herbicide on PEC/CS/TPP nanoparticles reduced acute lung injury and fibrosis. The encapsulation also led to lower apoptosis, oxidative stress and alpha-SMA expression in the lung tissue.

Prolyl Hydroxylase Inhibitors: a New Opportunity in Renal and Myocardial Protection

Hypoxia, via the activity of hypoxia-inducible factors (HIFs), plays a crucial role in fibrosis, inflammation, and oxidative injury, processes which are associated with progression of cardiovascular and kidney diseases. HIFs are key transcription heterodimers consisting of regulatory α-subunits (HIF-1α, HIF-2α, HIF-3α) and a constitutive β-subunit (HIF-β). The stability of HIFs is regulated by the prolyl hydroxylases (PHDs). Specific PHD inhibitors (PHD-i) are being investigated as a therapeutic approach to modulate the cellular signaling pathways and harness the native protective adaptive responses to hypoxia. Selective inhibition of PHD leads to the stabilization of the HIFs, which is the transcriptional gatekeeper of a multitude of genes involved in angiogenesis, energy metabolism, apoptosis, inflammation, and fibrosis. PHD-i downregulate hepcidin, improve iron absorption, and increase the endogenous production of erythropoietin. Furthermore, this pharmacological group has also been proven to ameliorate ischemic injuries in several organs, opening a new and promising field in cardiovascular research.. In this review, we present the basic and clinical potential of PHD-i treatment in different scenarios, such as ischemic heart disease, cardiac hypertrophy and heart failure, and their interplay with other pharmacological agents with proven cardiovascular benefits, such as sodium-glucose cotransporter 2 (SGLT2) inhibitors.

Novel Role of miR-18a-5p and Galanin in Rat Lung Ischemia Reperfusion-Mediated Response

Lung ischemia reperfusion (IR) is known to occur after lung transplantation or cardiac bypass. IR leads to tissue inflammation and damage and is also associated with increased morbidity and mortality. Various receptors are known to partake in activation of the innate immune system, but the downstream mechanism of tissue damage and inflammation is yet unknown. MicroRNAs (miRNAs) are in the forefront in regulating ischemia reperfusion injury and are involved in inflammatory response. Here, we have identified by high-throughput approach and evaluated a distinct set of miRNAs that may play a role in response to IR in rat lung tissue. The top three differentially expressed miRNAs were validated through quantitative PCRs in the IR rat lung model and an in vitro model of IR of hypoxia and reoxygenation exposed type II alveolar cells. Among the miRNAs, miR-18a-5p showed consistent downregulation in both the model systems on IR. Cellular and molecular analysis brought to light a crucial role of this miRNA in ischemia reperfusion. miR-18a-5p plays a role in IR-mediated apoptosis and ROS production and regulates the expression of neuropeptide Galanin. It also influences the nuclear localization of transcription factor: nuclear factor-erythroid 2-related factor (Nrf2) which in turn may regulate the expression of the miR-18a gene. Thus, we have not only established a rat model for lung IR and enumerated the important miRNAs involved in IR but have also extensively characterized the role of miR-18a-5p. This study will have important clinical and therapeutic implications for and during transplantation procedures.

Reactive oxygen species-based nanomaterials for the treatment of myocardial ischemia reperfusion injuries

Interventional coronary reperfusion strategies are widely adopted to treat acute myocardial infarction, but morbidity and mortality of acute myocardial infarction are still high. Reperfusion injuries are inevitable due to the generation of reactive oxygen species (ROS) and apoptosis of cardiac muscle cells. However, many antioxidant and anti-inflammatory drugs are largely limited by pharmacokinetics and route of administration, such as short half-life, low stability, low bioavailability, and side effects for treatment myocardial ischemia reperfusion injury. Therefore, it is necessary to develop effective drugs and technologies to address this issue. Fortunately, nanotherapies have demonstrated great opportunities for treating myocardial ischemia reperfusion injury. Compared with traditional drugs, nanodrugs can effectively increase the therapeutic effect and reduces side effects by improving pharmacokinetic and pharmacodynamic properties due to nanodrugs’ size, shape, and material characteristics. In this review, the biology of ROS and molecular mechanisms of myocardial ischemia reperfusion injury are discussed. Furthermore, we summarized the applications of ROS-based nanoparticles, highlighting the latest achievements of nanotechnology researches for the treatment of myocardial ischemia reperfusion injury.

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Cardiovascular diseases are the leading cause of death worldwide. Researches of the myocardial infarction pathology and development of new treatments have very important scientific significance in the biomedical field.

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Many nanomaterials have shown amazing therapeutic effects to reduce myocardial damage by eliminating ROS.

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Nanomaterials effectively reduced myocardial damage through eliminating ROS from NOXs, M-ETC, M-Ca²⁺, M-mPTP, and RIRR.

MicroRNA-29b reduces myocardial ischemia-reperfusion injury in rats via down-regulating PTEN and activating the Akt/eNOS signaling pathway

Reperfusion may cause injuries to the myocardium in ischemia situation, which is called ischemia/reperfusion (I/R) injury. The study aimed to explore the roles of microRNA-29b (miR-29b) in myocardial I/R injury. Myocardial I/R injury rat model was established. Differentially expressed miRNAs between the model rats and the sham-operated rats were analyzed. miR-29b expression in myocardial tissues was measured. Gain-of-function of miR-29b was performed, and then the morphological changes, infarct size, myocardial function, oxidative stress, and the cell apoptosis in myocardial tissues were detected. The target relation between miR-29b and PTEN was detected through bio-information prediction and dual luciferase reporter gene assay. Activation of Akt/eNOS signaling was detected. H9C2 cells were subjected to hypoxia/reoxygenation treatment to perform in vitro experiments. I/R rats presented severe inflammatory infiltration, increased infarct size and cell apoptosis, increased oxidative stress and decreased myocardial function. miR-29b was downregulated in I/R rats, and up-regulation of miR-29b reversed the above changes. miR-29b directly bound to PTEN, and overexpression of miR-29b reduced PTEN expression level and increased the protein levels of p-Akt/Akt and p-eNOS/eNOS. In vivo results were confirmed in in vitro experiments. This study provided evidence that miR-29b could alleviate the myocardial I/R injury in vivo and in vitro by inhibiting PTEN expression and activating the Akt/eNOS signaling pathway.

Protopanaxadiol and protopanaxatriol ginsenosides can protect against aconitine-induced injury in H9c2 cells by maintaining calcium homeostasis and activating the AKT pathway

ABSTRACT

The present study aimed to investigate the effects of protopanaxadiol and protopanaxatriol ginsenosides on aconitine induced cardiomyocyte injury and their regulatory mechanisms. The effects of ginsenosides on aconitine-induced cardiomyocyte damage were initially evaluated using H9c2 cells, and the molecular mechanisms were elucidated via molecular docking and western blotting. The changes in enzyme content, reactive oxygen species (ROS), calcium (Ca2+) concentration and apoptosis were determined. Furthermore, an aconitine-induced cardiac injury rat model was established, the cardiac injury and serum physiological and biochemical indexes were measured, and the effects of ginsenoside were observed. The results showed that ginsenoside Rb1 significantly increased aconitine-induced cell viability, and its binding conformation with AKT protein was the most significant. In vitro and in vivo, Rb1 protects cardiomyocytes from aconitine-induced injury by regulating oxidative stress levels and maintaining Ca2+ concentration homeostasis. Moreover, Rb1 activated the PI3K/AKT pathway, down-regulated Cleaved caspase-3 and Bax, and up-regulated Bcl-2 expression. In conclusion, Rb1 protected H9c2 cells from aconitine-induced injury by maintaining Ca2+ homeostasis and activating the PI3K/AKT pathway to induce a cascade response of downstream proteins, thereby protecting cardiomyocytes from damage. These results suggested that ginsenoside Rb1 may be a potential cardiac protective drug.

Sirtuin 1 activated by SRT1460 protects against myocardial ischemia/reperfusion injury

BACKGROUND

Ischemia reperfusion usually results in certain degree of damage to the myocardium, which is called myocardial ischemia/reperfusion (I/R) injury.

OBJECTIVE

Previous studies have found that Sirt1 plays a critical role in I/R injury by protecting cardiac function. SRT1460 is the activator for Sirt1 that participates in the regulation of various diseases. However, whether SRT1460 has any effects on myocardial I/R injury needs further study.

METHODS

The I/R rat model and H/R H9C2 model were established to simulate myocardial I/R injury. The infarct area of the rat heart was examined through TTC staining. The EF and FS of rats were detected through echocardiography. The levels of CK-MB, LDH, MDA, SOD and CK in cardiac tissues, serum or H9C2 cells were measured using commercial kits. Cell viability was assessed through MTT assay. Apoptosis was determined through flow cytometry analysis. Sirt1 expression was measured through western blot.

RESULTS

Our work found that SRT1460 reduced the infarct area of the heart induced by myocardial I/R injury. In addition, SRT1460 was confirmed to ameliorate cardiac dysfunction induced by myocardial I/R injury. Further exploration discovered that SRT1460 weakened oxidative stress induced by myocardial I/R injury. Findings from in vitro assays demonstrated that SRT1460 relieved injury of H/R-treated H9C2 cells. Finally, rescue assays proved that Sirt1 knockdown reversed the protective effects of SRT1460 on the injury of H/R-treated H9C2 cells.

CONCLUSION

Sirt1 activated by SRT1460 protected against myocardial I/R injury. This discovery may offer new sights on the treatment of myocardial I/R injury.

CTRP13 Protects H9c2 Cells Against Hypoxia/Reoxygenation (H/R)-Induced Injury Via Regulating the AMPK/Nrf2/ARE Signaling Pathway

Myocardial infarction (MI) is identified as the myocardial necrosis due to myocardial ischemia/reperfusion (I/R) injury and remains a leading cause of mortality. C1q/TNF-related protein 13 (CTRP13) is a member of CTRP family that has been found to be involved in coronary artery disease (CAD). However, the role of CTRP13 in MI remains unclear. We aimed to explore the functional role of CTRP13 in H9c2 cells exposed to hypoxia/reoxygenation (H/R). Our results demonstrated that H/R stimulation significantly decreased the expression of CTRP13 in H9c2 cells. H/R-induced an increase in ROS production and reductions in activities of SOD and CAT were prevented by CTRP13 overexpression but were aggravated by CTRP13 silencing. Moreover, CTRP13 overexpression could reverse the inductive effect of H/R on caspase-3 activity and bax expression, as well as the inhibitory effect of H/R on bcl-2 expression in H9c2 cells. However, CTRP13 silencing presented opposite effects with CTRP13 overexpression. Furthermore, CTRP13 overexpression enhanced the H/R-stimulated the expression levels of p-AMPK and nuclear Nrf2, and Nrf2 transcriptional activity. However, inhibition of AMPK reversed the CTRP13-mediated activation of Nrf2/ARE signaling and the cardiac-protective effect in H/R-exposed H9c2 cells. Additionally, silencing of Nrf2 reversed the protective effects of CTRP13 against H/R-stimulated oxidative stress and apoptosis in H9c2 cells. Finally, recombinant CTRP13 protein attenuated myocardial I/R-induced injury in rats. Taken together, these findings indicated that CTRP13 protected H9c2 cells from H/R-stimulated oxidative stress and apoptosis via regulating the AMPK/Nrf2/ARE signaling pathway. Our results provided evidence for the therapeutic potential of CTRP13 in myocardial I/R injury.

Exendin-4 Protects Against Myocardial Ischemia-Reperfusion Injury by Upregulation of SIRT1 and SIRT3 and Activation of AMPK

This study evaluated if the cardioprotective effect of Exendin-4 against ischemia/reperfusion (I/R) injury in male rats involves modulation of AMPK and sirtuins. Adult male rats were divided into sham, sham + Exendin-4, I/R, I/R + Exendin-4, and I/R + Exendin-4 + EX-527, a sirt1 inhibitor. Exendin-4 reduced infarct size and preserved the function and structure of the left ventricles (LV) of I/R rats. It also inhibited oxidative stress and apoptosis and upregulated MnSOD and Bcl-2 in their infarcted myocardium. With no effect on SIRTs 2/6/7, Exendin-4 activated and upregulated mRNA and protein levels of SIRT1, increased levels of SIRT3 protein, activated AMPK, and reduced the acetylation of p53 and PGC-1α as well as the phosphorylation of FOXO-1. EX-527 completely abolished all beneficial effects of Exendin-4 in I/R-induced rats. In conclusion, Exendin-4 cardioprotective effect against I/R involves activation of SIRT1 and SIRT3. Graphical Abstract Exendin-4 could scavenge free radical directly, upregulate p53, and through upregulation of SIRT1 and stimulating SIRT1 nuclear accumulation. In addition, Exendin-4 also upregulates SIRT3 which plays an essential role in the upregulation of antioxidants, inhibition of reactive oxygen species (ROS) generation, and prevention of mitochondria damage. Accordingly, SIRT1 induces the deacetylation of PGC-1α and p53 and is able to bind p-FOXO-1. This results in inhibition of cardiomyocyte apoptosis through increasing Bcl-2 levels, activity, and levels of MnSOD; decreasing expression of Bax; decreasing cytochrome C release; and improving mitochondria biogenesis through upregulation of Mfn-2.

Glutathione Participation in the Prevention of Cardiovascular Diseases

Cardiovascular diseases (CVD) (such as occlusion of the coronary arteries, hypertensive heart diseases and strokes) are diseases that generate thousands of patients with a high mortality rate worldwide. Many of these cardiovascular pathologies, during their development, generate a state of oxidative stress that leads to a deterioration in the patient's conditions associated with the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Within these reactive species we find superoxide anion (O2•-), hydroxyl radical (•OH), nitric oxide (NO•), as well as other species of non-free radicals such as hydrogen peroxide (H2O2), hypochlorous acid (HClO) and peroxynitrite (ONOO-). A molecule that actively participates in counteracting the oxidizing effect of reactive species is reduced glutathione (GSH), a tripeptide that is present in all tissues and that its synthesis and/or regeneration is very important to be able to respond to the increase in oxidizing agents. In this review, we will address the role of glutathione, its synthesis in both the heart and the liver, and its importance in preventing or reducing deleterious ROS effects in cardiovascular diseases.

Chitosan and Curcumin Nanoformulations against Potential Cardiac Risks Associated with Hydroxyapatite Nanoparticles in Wistar Male Rats

Nanoparticle-induced cardiovascular diseases have attracted much attention. Upon entering the blood circulation system, these particles have the potency to induce cardiomyocytes, leading to cardiac failure or myocardial ischemia, and the molecular mechanism remains to be completely clarified. In this study, the cardiac toxicity of rats orally exposed to hydroxyapatite nanoparticles (HAPNPs) has been observed through an increase in myocardial infarction serum markers including CK-MB and alterations in routine blood factors, expression of apoptosis-related protein P53, and increased levels of serum inflammatory markers represented by the tumor necrosis factor alpha and Interleukin-6, as well as a decline in heart antioxidant enzymes and reduced glutathione level, while an induction in lipid peroxidation and nitric oxide has been observed, as well as notable histological and histochemical alterations in the heart of these animals. mRNA and protein expressions of vascular endothelial growth factor (VEGF-A), cyclooxygenase-2 (COX-2), and atrial natriuretic factor (ANF) were elevated in the myocardium. However, the coadministration of chitosan nanoparticles (CsNPs) and/or curcumin nanoparticles (CurNPs) successfully modulated these alterations and induced activation in antioxidant parameters. The present data suggest that HAPNPs-induced apoptosis via the mitochondrial pathway may play a crucial role in cardiac tissue damage and the early treatment with CsNPs and CurNPs may protect the heart from infarction induced by HAPNPs toxic effect.

Inhibition of Cardiac RIP3 Mitigates Early Reperfusion Injury and Calcium-Induced Mitochondrial Swelling without Altering Necroptotic Signalling

Receptor-interacting protein kinase 3 (RIP3) is a convergence point of multiple signalling pathways, including necroptosis, inflammation and oxidative stress; however, it is completely unknown whether it underlies acute myocardial ischemia/reperfusion (I/R) injury. Langendorff-perfused rat hearts subjected to 30 min ischemia followed by 10 min reperfusion exhibited compromised cardiac function which was not abrogated by pharmacological intervention of RIP3 inhibition. An immunoblotting analysis revealed that the detrimental effects of I/R were unlikely mediated by necroptotic cell death, since neither the canonical RIP3-MLKL pathway (mixed lineage kinase-like pseudokinase) nor the proposed non-canonical molecular axes involving CaMKIIδ-mPTP (calcium/calmodulin-dependent protein kinase IIδ-mitochondrial permeability transition pore), PGAM5-Drp1 (phosphoglycerate mutase 5-dynamin-related protein 1) and JNK-BNIP3 (c-Jun N-terminal kinase-BCL2-interacting protein 3) were activated. Similarly, we found no evidence of the involvement of NLRP3 inflammasome signalling (NOD-, LRR- and pyrin domain-containing protein 3) in such injury. RIP3 inhibition prevented the plasma membrane rupture and delayed mPTP opening which was associated with the modulation of xanthin oxidase (XO) and manganese superoxide dismutase (MnSOD). Taken together, this is the first study indicating that RIP3 regulates early reperfusion injury via oxidative stress- and mitochondrial activity-related effects, rather than cell loss due to necroptosis.

Skeletal Muscle Nrf2 Contributes to Exercise-Evoked Systemic Antioxidant Defense Via Extracellular Vesicular Communication

This review explores the hypothesis that the repetitive contraction-relaxation that occurs during chronic exercise activates skeletal myocyte nuclear factor erythroid-derived 2-like 2 (Nrf2) to upregulate antioxidant enzymes. These proteins are secreted into the circulation within extracellular vesicles and taken up by remote cells, thus providing remote organs with cytoprotection against subsequent oxidative stress.

Lung Transplantation, Pulmonary Endothelial Inflammation, and Ex-Situ Lung Perfusion: A Review

Lung transplantation (LTx) is the gold standard treatment for end-stage lung disease; however, waitlist mortality remains high due to a shortage of suitable donor lungs. Organ quality can be compromised by lung ischemic reperfusion injury (LIRI). LIRI causes pulmonary endothelial inflammation and may lead to primary graft dysfunction (PGD). PGD is a significant cause of morbidity and mortality post-LTx. Research into preservation strategies that decrease the risk of LIRI and PGD is needed, and ex-situ lung perfusion (ESLP) is the foremost technological advancement in this field. This review addresses three major topics in the field of LTx: first, we review the clinical manifestation of LIRI post-LTx; second, we discuss the pathophysiology of LIRI that leads to pulmonary endothelial inflammation and PGD; and third, we present the role of ESLP as a therapeutic vehicle to mitigate this physiologic insult, increase the rates of donor organ utilization, and improve patient outcomes.

A meta-analysis of randomized clinical trials on the impact of oral vitamin C supplementation on first-year outcomes in orthopedic patients

This meta-analysis aimed at investigating the impact of oral vitamin C supplementation on the post-procedural recovery of orthopedic patients, including functional outcomes and complex regional pain syndrome type I (CRPS I). Literature search using the Medline, Cochrane Library, and Embase databases from inception till March 2021 identified seven eligible randomized controlled trials with 1,361 participants. Forest plot revealed no significant difference in the functional outcomes at 6-12 months [standardized mean difference (SMD) = -0.00, 95% CI - 0.19 to 0.18, 467 patients], risk of overall complications (RR = 0.98, 95% CI 0.68 to 1.39, 426 patients), and pain severity at 3-6 months (SMD = - 0.18, 95% CI - 0.49 to 0.12, 486 patients) between patients with and without oral vitamin C supplementation. Pooled analysis showed that vitamin C treatment reduced the risk of CRPS I regardless of dosage (RR = 0.46, 95% CI 0.25 to 0.85, 1143 patients). In conclusion, the current meta-analysis demonstrated that oral vitamin C supplementation may reduce the risk of complex regional pain syndrome type I but did not improve the functional outcomes in orthopedic patients. Nevertheless, because of the small number of trials included in the present study, further large-scale clinical studies are warranted to support our findings.

Targeting Ferroptosis against Ischemia/Reperfusion Cardiac Injury

Ischemic heart disease is a leading cause of death worldwide. Primarily, ischemia causes decreased oxygen supply, resulting in damage of the cardiac tissue. Naturally, reoxygenation has been recognized as the treatment of choice to recover blood flow through primary percutaneous coronary intervention. This treatment is the gold standard therapy to restore blood flow, but paradoxically it can also induce tissue injury. A number of different studies in animal models of acute myocardial infarction (AMI) suggest that ischemia-reperfusion injury (IRI) accounts for up to 50% of the final myocardial infarct size. Oxidative stress plays a critical role in the pathological process. Iron is an essential mineral required for a variety of vital biological functions but also has potentially toxic effects. A detrimental process induced by free iron is ferroptosis, a non-apoptotic type of programmed cell death. Accordingly, efforts to prevent ferroptosis in pathological settings have focused on the use of radical trapping antioxidants (RTAs), such as liproxstatin-1 (Lip-1). Hence, it is necessary to develop novel strategies to prevent cardiac IRI, thus improving the clinical outcome in patients with ischemic heart disease. The present review analyses the role of ferroptosis inhibition to prevent heart IRI, with special reference to Lip-1 as a promising drug in this clinicopathological context.

Cardioprotective effect of anisodamine against ischemia/reperfusion injury through the mitochondrial ATP-sensitive potassium channel

Previous clinical studies have shown that anisodamine could improve no-reflow phenomenon and prevent reperfusion arrhythmias, but whether this protective effect is related to the antagonism of the M-type cholinergic receptor or other potential mechanisms is uncertain. The aim of the present study was to investigate the role of the mitochondrial ATP-sensitive potassium channel (mitoK ATP ) in cardioprotective effect of anisodamine against ischemia/reperfusion injury. Anisodamine and 5- hydroxydecanoic acid were used to explore the relationship between anisodamine and mitoK ATP . Using a Langendorff isolated heart ischemia/reperfusion injury model, hemodynamic parameters and reperfusion ventricular arrhythmia were evaluated; in addition, changes in myocardial infarct size, cTnI from coronary effluent and myocardial ultrastructure, as well as ATP, MDA and SOD in myocardial tissues, were detected. In the hypoxia/reoxygenation injury model of neonatal rat cardiomyocyte, cTnI release in the culture medium and levels of ATP, MDA and SOD in cardiomyocytes and mitochondrial membrane potential, were analyzed. Overall, anisodamine could significantly improve the hemodynamic indexes of isolated rat heart injured by ischemia/reperfusion, reduce the occurrence of ventricular reperfusion arrhythmia and myocardial infarction area, and improve the ultrastructural damage of myocardium and mitochondria. The in vitro results demonstrated that anisodamine could improve mitochondrial energy metabolism, reduce oxidative stress and stabilize mitochondrial membrane potential. The cardioprotective effects were significantly inhibited by 5-hydroxydecanoic acid. In conclusion, this study suggests that the opening of mitoK ATP could play an important role in the protective effect of anisodamine against myocardial ischemia/reperfusion injury.

Peritransplant Cardiometabolic and Mitochondrial Function: The Missing Piece in Donor Heart Dysfunction and Graft Failure

Primary graft dysfunction is an important cause of morbidity and mortality after cardiac transplantation. Donor brain stem death (BSD) is a significant contributor to donor heart dysfunction and primary graft dysfunction. There remain substantial gaps in the mechanistic understanding of peritransplant cardiac dysfunction. One of these gaps is cardiac metabolism and metabolic function. The healthy heart is an "omnivore," capable of utilizing multiple sources of nutrients to fuel its enormous energetic demand. When this fails, metabolic inflexibility leads to myocardial dysfunction. Data have hinted at metabolic disturbance in the BSD donor and subsequent heart transplantation; however, there is limited evidence demonstrating specific metabolic or mitochondrial dysfunction. This review will examine the literature surrounding cardiometabolic and mitochondrial function in the BSD donor, organ preservation, and subsequent cardiac transplantation. A more comprehensive understanding of this subject may then help to identify important cardioprotective strategies to improve the number and quality of donor hearts.

Cell therapy for the treatment of heart disease: Renovation work on the broken heart is still in progress

Cardiovascular disease (CVD) continues to be the number one killer in the aging population. Heart failure (HF) is also an important cause of morbidity and mortality in patients with congenital heart disease (CHD). Novel therapeutic approaches that could restore stable heart function are much needed in both paediatric and adult patients. Regenerative medicine holds promises to provide definitive solutions for correction of congenital and acquired cardiac defects. In this review article, we recap some important aspects of cardiovascular cell therapy. First, we report quantifiable data regarding the scientific advancements in the field and how this has been translated into tangible outcomes according clinical studies and related meta-analyses. We then comment on emerging trends and technologies, such as the use of second-generation cell products, including pericyte-like vascular progenitors, and reprogramming of cells by different approaches including modulation of oxidative stress. The more affordable and feasible strategy of repurposing clinically available drugs to awaken the intrinsic healing potential of the heart will be discussed in the light of current social, financial, and ethical context. Cell therapy remains a work in progress field. Uncertainty in the ability of the experts and policy makers to solve urgent medical problems is growing in a world that is significantly influenced by them. This is particularly true in the field of regenerative medicine, due to great public expectations, polarization of leadership and funding, and insufficient translational vision. Cardiovascular regenerative medicine should be contextualized in a holistic program with defined priorities to allow a complete realization. Reshaping the notion of medical expertise is fundamental to fill the current gap in translation.

ELAVL1 is transcriptionally activated by FOXC1 and promotes ferroptosis in myocardial ischemia/reperfusion injury by regulating autophagy

Aims

Myocardial ischemia is the most common form of cardiovascular disease and the leading cause of morbidity and mortality. Understanding the mechanisms is very crucial for the development of effective therapy. Therefore, this study aimed to investigate the functional roles and mechanisms by which ELAVL1 regulates myocardial ischemia and reperfusion (I/R) injury.

Methods

Mouse myocardial I/R model and cultured myocardial cells exposed to hypoxia/reperfusion (H/R) were used in this study. Features of ferroptosis were evidenced by LDH activity, GPx4 activity, cellular iron, ROS, LPO, and GSH levels. The expression levels of autophagy markers (Beclin-1, p62, LC3), ELAVL1 and FOXC1 were measured by qRT-PCR, immunostaining and western blot. RIP assay, biotin-pull down, ChIP and dual luciferase activity assay were employed to examine the interactions of ELAVL1/Beclin-1 mRNA and FOXC1/ELAVL1 promoter. CCK-8 assay was used to examine viability of cells. TTC staining was performed to assess the myocardial I/R injury.

Results

Myocardial I/R surgery induced ferroptosis and up-regulated ELAVL1 level. Knockdown of ELAVL1 decreased ferroptosis and ameliorated I/R injury. Si-ELAVL1 repressed autophagy and inhibition of autophagy by inhibitor suppressed ferroptosis and I/R injury in myocardial cells. Increase of autophagy could reverse the effects of ELAVL1 knockdown on ferroptosis and I/R injury. ELAVL1 directly bound with and stabilized Beclin-1 mRNA. Furthermore, FOXC1 bound to ELAVL1 promoter region and activated its transcription upon H/R exposure.

Conclusion

FOXC1 transcriptionally activated ELAVL1 may promote ferroptosis during myocardial I/R by modulating autophagy, leading to myocardial injury. Inhibition of ELAVL1-mediated autophagic ferroptosis would be a new viewpoint in the treatment of myocardial I/R injury.