Amelioration of myocardial ischemia/reperfusion injury in diabetes: A narrative review of the mechanisms and clinical applications of dexmedetomidine

DEX Inhibits H/R-induced Cardiomyocyte Ferroptosis by the miR-141-3p/lncRNA TUG1 Axis

BACKGROUND

 Ferroptosis is emerging as a critical pathway in ischemia/reperfusion (I/R) injury, contributing to compromised cardiac function and predisposing individuals to sepsis and myocardial failure. The study investigates the underlying mechanism of dexmedetomidine (DEX) in hypoxia/reoxygenation (H/R)-induced ferroptosis in cardiomyocytes, aiming to identify novel targets for myocardial I/R injury treatment.

METHODS

 H9C2 cells were subjected to H/R and treated with varying concentrations of DEX. Additionally, H9C2 cells were transfected with miR-141-3p inhibitor followed by H/R treatment. Levels of miR-141-3p, long noncoding RNA (lncRNA) taurine upregulated 1 (TUG1), Fe2+, glutathione (GSH), and malondialdehyde were assessed. Reactive oxygen species (ROS) generation was measured via fluorescent labeling. Expression of ferroptosis-related proteins glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase long-chain family member 4 (ACSL4) was determined using Western blot. The interaction between miR-141-3p and lncRNA TUG1 was evaluated through RNA pull-down assay and dual-luciferase reporter gene assays. The stability of lncRNA TUG1 was assessed using actinomycin D.

RESULTS

 DEX ameliorated H/R-induced cardiomyocyte injury and elevated miR-141-3p expression in cardiomyocytes. DEX treatment increased cell viability, Fe2+, and ROS levels while decreasing ACSL4 protein expression. Furthermore, DEX upregulated GSH and GPX4 protein levels. miR-141-3p targeted lncRNA TUG1, reducing its stability and overall expression. Inhibition of miR-141-3p or overexpression of lncRNA TUG1 partially reversed the inhibitory effect of DEX on H/R-induced ferroptosis in cardiomyocytes.

CONCLUSION

 DEX mitigated H/R-induced ferroptosis in cardiomyocytes by upregulating miR-141-3p expression and downregulating lncRNA TUG1 expression, unveiling a potential therapeutic strategy for myocardial I/R injury.

Breviscapine alleviates myocardial ischemia-reperfusion injury in diabetes rats

PURPOSE

To investigate the protective effect of breviscapine on myocardial ischemia-reperfusion injury (MIRI) in diabetes rats.

METHODS

Forty rats were divided into control, diabetes, MIRI of diabetes, and treatment groups. The MIRI of diabetes model was established in the latter two groups. Then, the treatment group was treated with 100 mg/kg breviscapine by intraperitoneal injection for 14 consecutive days.

RESULTS

After treatment, compared with MIRI of diabetes group, in treatment group the serum fasting blood glucose, fasting insulin, homeostasis model assessment of insulin resistance, and glycosylated hemoglobin levels decreased, the serum total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol levels decreased, the serum high-density lipoprotein cholesterol level increased, the heart rate decreased, the mean arterial pressure, left ventricular ejection fraction, and fractional shortening increased, the serum cardiac troponin I, and creatine kinase-MB levels decreased, the myocardial tumor necrosis factor α and interleukin-6 levels decreased, the myocardial superoxide dismutase level increased, and the myocardial malondialdehyde level decreased (all P < 0.05).

CONCLUSIONS

For treating MIRI of diabetes in rats, the breviscapine can reduce the blood glucose and lipid levels, improve the cardiac function, reduce the myocardial injury, and decrease the inflammatory response and oxidative stress, thus exerting the alleviating effect.

Salvianolic acids and its potential for cardio-protection against myocardial ischemic reperfusion injury in diabetes

The incidence of diabetes and related mortality rate increase yearly in modern cities. Additionally, elevated glucose levels can result in an increase of reactive oxygen species (ROS), ferroptosis, and the disruption of protective pathways in the heart. These factors collectively heighten the vulnerability of diabetic individuals to myocardial ischemia. Reperfusion therapies have been effectively used in clinical practice. There are limitations to the current clinical methods used to treat myocardial ischemia-reperfusion injury. As a result, reducing post-treatment ischemia/reperfusion injury remains a challenge. Therefore, efforts are underway to provide more efficient therapy. Salvia miltiorrhiza Bunge (Danshen) has been used for centuries in ancient China to treat cardiovascular diseases (CVD) with rare side effects. Salvianolic acid is a water-soluble phenolic compound with potent antioxidant properties and has the greatest hydrophilic property in Danshen. It has recently been discovered that salvianolic acids A (SAA) and B (SAB) are capable of inhibiting apoptosis by targeting the JNK/Akt pathway and the NF-κB pathway, respectively. This review delves into the most recent discoveries regarding the therapeutic and cardioprotective benefits of salvianolic acid for individuals with diabetes. Salvianolic acid shows great potential in myocardial protection in diabetes mellitus. A thorough understanding of the protective mechanism of salvianolic acid could expand its potential uses in developing medicines for treating diabetes mellitus related myocardial ischemia-reperfusion.

SIRT1 is a regulator of autophagy: Implications for the progression and treatment of myocardial ischemia-reperfusion

SIRT1 is a highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase. It is involved in the regulation of various pathophysiological processes, including cell proliferation, survival, differentiation, autophagy, and oxidative stress. Therapeutic activation of SIRT1 protects the heart and cardiomyocytes from pathology-related stress, particularly myocardial ischemia/reperfusion (I/R). Autophagy is an important metabolic pathway for cell survival during energy or nutrient deficiency, hypoxia, or oxidative stress. Autophagy is a double-edged sword in myocardial I/R injury. The activation of autophagy during the ischemic phase removes excess metabolic waste and helps ensure cardiomyocyte survival, whereas excessive autophagy during reperfusion depletes the cellular components and leads to autophagic cell death. Increasing research on I/R injury has indicated that SIRT1 is involved in the process of autophagy and regulates myocardial I/R. SIRT1 regulates autophagy through various pathways, such as the deacetylation of FOXOs, ATGs, and LC3. Recent studies have confirmed that SIRT1-mediated autophagy plays different roles at different stages of myocardial I/R injury. By targeting the mechanism of SIRT1-mediated autophagy at different stages of I/R injury, new small-molecule drugs, miRNA activators, or blockers can be developed. For example, resveratrol, sevoflurane, quercetin, and melatonin in the ischemic stage, coptisine, curcumin, berberine, and some miRNAs during reperfusion, were involved in regulating the SIRT1-autophagy axis, exerting a cardioprotective effect. Here, we summarize the possible mechanisms of autophagy regulation by SIRT1 in myocardial I/R injury and the related molecular drug applications to identify strategies for treating myocardial I/R injury.

Network-pharmacology-based research on protective effects and underlying mechanism of Shuxin decoction against myocardial ischemia/reperfusion injury with diabetes

BACKGROUND

Patients with diabetes mellitus are at higher risk of myocardial ischemia/ reperfusion injury (MI/RI). Shuxin decoction (SXT) is a proven recipe modi-fication from the classic herbal formula "Wu-tou-chi-shi-zhi-wan" according to the traditional Chinese medicine theory. It has been successfully used to alleviate secondary MI/RI in patients with diabetes mellitus in the clinical setting. However, the underlying mechanism is still unclear.

AIM

To further determine the mechanism of SXT in attenuating MI/RI associated with diabetes.

METHODS

This paper presents an ensemble model combining network pharmacology and biology. The Traditional Chinese Medicine System Pharmacology Database was accessed to select key components and potential targets of the SXT. In parallel, therapeutic targets associated with MI/RI in patients with diabetes were screened from various databases including Gene Expression Omnibus, DisGeNet, Genecards, Drugbank, OMIM, and PharmGKB. The potential targets of SXT and the therapeutic targets related to MI/RI in patients with diabetes were intersected and subjected to bioinformatics analysis using the Database for Annotation, Visualization and Integrated Discovery. The major results of bioinformatics analysis were subsequently validated by animal experiments.

RESULTS

According to the hypothesis derived from bioinformatics analysis, SXT could possibly ameliorate lipid metabolism disorders and exert anti-apoptotic effects in MI/RI associated with diabetes by reducing oxidized low density lipoprotein (LDL) and inhibiting the advanced glycation end products (AGE)-receptor for AGE (RAGE) signaling pathway. Subsequent animal experiments confirmed the hypothesis. The treatment with a dose of SXT (2.8 g/kg/d) resulted in a reduction in oxidized LDL, AGEs, and RAGE, and regulated the level of blood lipids. Besides, the expression of apoptosis-related proteins such as Bax and cleaved caspase 3 was down-regulated, whereas Bcl-2 expression was up-regulated. The findings indicated that SXT could inhibit myocardial apoptosis and improve cardiac function in MI/RI in diabetic rats.

CONCLUSION

This study indicated the active components and underlying molecular therapeutic mechanisms of SXT in MI/RI with diabetes. Moreover, animal experiments verified that SXT could regulate the level of blood lipids, alleviate cardiomyocyte apoptosis, and improve cardiac function through the AGE-RAGE signaling pathway.

MicroRNAs in the Regulation of NADPH Oxidases in Vascular Diabetic and Ischemic Pathologies: A Case for Alternate Inhibitory Strategies?

Since their discovery in the vasculature, different NADPH oxidase (NOX) isoforms have been associated with numerous complex vascular processes such as endothelial dysfunction, vascular inflammation, arterial remodeling, and dyslipidemia. In turn, these often underlie cardiovascular and metabolic pathologies including diabetes mellitus type II, cardiomyopathy, systemic and pulmonary hypertension and atherosclerosis. Increasing attention has been directed toward miRNA involvement in type II diabetes mellitus and its cardiovascular and metabolic co-morbidities in the search for predictive and stratifying biomarkers and therapeutic targets. Owing to the challenges of generating isoform-selective NOX inhibitors (NOXi), the development of specific NOXis suitable for therapeutic purposes has been hindered. In that vein, differential regulation of specific NOX isoforms by a particular miRNA or combina-tion thereof could at some point become a reasonable approach for therapeutic targeting under some circumstances. Whereas administration of miRNAs chronically, or even acutely, to patients poses its own set of difficulties, miRNA-mediated regulation of NOXs in the vasculature is worth surveying. In this review, a distinct focus on the role of miRNAs in the regulation of NOXs was made in the context of type II diabetes mellitus and ischemic injury models.

Targeted activation of ERK1/2 reduces ischemia and reperfusion injury in hyperglycemic myocardium by improving mitochondrial function

Background

Diabetes can increase the risk of coronary heart disease, and also increase the mortality rate of coronary heart disease in diabetic patients. Although reperfusion therapy can preserve the viable myocardium, fatal reperfusion injury can also occur. Studies have shown that diabetes can aggravate myocardial ischemia-reperfusion injury, ERK1/2 can reduce myocardial ischemia-reperfusion injury, but its mechanism in hyperglycemic myocardial ischemia-reperfusion injury is unclear. This study sought to explore the mechanism of extracellular signal-regulated kinase 1/2 (ERK1/2) in hyperglycemic myocardial ischemia reperfusion (I/R) injury.

Methods

H9C2 cardiomyocytes were treated with high-glucose (HG) medium plus I/R stimulation to establish a hyperglycemia I/R model in vitro. The cells were treated with LM22B-10 (an ERK activator) or transfected with the constitutive activation of the mitogen-activated protein kinase 1 (CaMEK) gene. Myocardial cell apoptosis, mitochondria functional-related indicators, the oxidative stress indexes, and the expression levels of ERK1/2 protein were detected.

Results

The HG I/R injury intervention caused an increase in the ratio of apoptotic cardiomyocytes (P<0.05), but the phosphorylation level of the ERK1/2 protein did not increase further. Administering LM22B-10 or transfecting the CaMEK gene significantly activated the phosphorylation levels of ERK1/2 protein and reduced the proportion of cardiomyocyte apoptosis (P<0.05). HG I/R injury increased mitochondrial fission and reduced membrane potential. The intervention reduced the number of punctate mitochondria, increased the average network structure size and median branch length (P<0.01), increased the median network structure size and average branch length (P<0.05), and reduced the colocalization of Drp1 (Dynamin-Related protein1)/TOMM20 (Mitochondrial outer membrane translocation enzyme 20) (P<0.05) and Drp1 with serine 616 phosphorylation (Drp1s616) phosphorylation (P<0.01), thereby reducing mitochondrial fission, increasing membrane potential and mitochondrial function. HG I/R injury increased the level of oxidative stress, while administering LM22B-10 or transfecting the CaMEK gene reduced the level of oxidative stress (P<0.01).

Conclusions

Targeting the activation of ERK1/2 protein phosphorylation reduced mitochondrial fission, increased membrane potential and mitochondrial function, reduced oxidative stress and myocardial cell apoptosis, and alleviated hyperglycemia myocardial I/R injury.