Alpha-lipoic acid potentiates the anti-arrhythmic effects of ischemic postconditioning in the setting of cardiac ischemia/reperfusion injury in diabetic rats

Superior Anti-arrhythmogenic Effect of Combined Conditioning with Nicotinamide Mononucleotide and Ubiquinol in Myocardial Ischemia/Reperfusion Injury in Aged Rats

Purpose

Lethal ventricular arrhythmias are a significant clinical concern following reperfusion therapies in elderly patients with myocardial infarction. The combination of multi-target therapies to achieve optimal anti-arrhythmogenesis and improve the chances of successful translation for patient benefit has prompted considerable interest. This study examined the anti-arrhythmic effect of nicotinamide mononucleotide (NMN)/ubiquinol combination treatment following myocardial ischemia/reperfusion (IR) injury in aged rats, with an emphasis on the role of oxidative stress and nitric oxide (NO).

Methods

Male Wistar rats (n=30, 22-24 months old, 400-450 g) were randomized into five groups with or without IR and/or NMN and ubiquinol, either alone or in combination. NMN (100 mg/kg/48 hours) was administered intraperitoneally for 28 days before IR, and ubiquinol (30 mg/kg) was injected intravenously at early reperfusion. Electrocardiographic signals were recorded during the ischemia and the first 30 minutes of reperfusion. Two hours after reperfusion, myocardial hemodynamic and LDH release were measured, and the left ventricle samples were obtained to evaluate oxidative stress markers and NO levels.

Results

NMN/ubiquinol combination treatment significantly minimized the occurrence and severity of IR-induced arrhythmias, improved myocardial function, and reduced LDH release (P<0.05). It also decreased MDA content, increased superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities, and enhanced NO formation (P<0.05). This combined treatment showed greater efficacy than the single treatments.

Conclusion

This study revealed the anti-arrhythmic effect of NMN/ubiquinol combination treatment in IR-treated aged rats, which may be associated with reduced oxidative stress and increased NO formation. This combinational approach deserves more investigation due to its potential to confer better anti-arrhythmic effect during aging.

Allicin Mitigates Diabetic Retinopathy in Rats by Activating Phosphatase and Tensin Homolog-induced Kinase 1/Parkin-mitophagy and Inhibiting Oxidative Stress-mediated NOD-like Receptor Family Pyrin Domain Containing 3 Inflammasome

ABSTRACT

Diabetic retinopathy (DR) is one of the significant disabling outcomes of diabetes mellitus characterized by retinal microvascular damage, inflammation, and neuronal dysfunction. Allicin (Alc), a natural compound found in garlic, has garnered attention for its antioxidant and anti-inflammatory properties, positioning it as a potential therapeutic agent for DR. The aim of the present study was to investigate the therapeutic efficacy of Alc in DR management and elucidate its underlying mechanisms of action. We established a DR model in male Sprague-Dawley rats (n = 50, 200-250 g, 12 weeks old) using a high-fat diet for 8 weeks plus a low dose of streptozotocin administered at the start of the 4th week. The diabetic (Diab) animals were administered Alc (16 mg/kg/day, orally), either alone or in combination with mitochondrial division inhibitor-1 (Mdivi-1) as a mitophagy inhibitor, starting 28 days before tissue sampling. We evaluated histopathological changes, metabolic abnormalities associated with type 2 diabetes mellitus (T2DM), the expression of proteins regulating pyroptosis (NOD-like receptor family pyrin domain containing 3, cleaved-caspase 1, and gasdermin D-N terminal) and mitophagy (phosphatase and tensin homolog-induced kinase 1 [PINK1] and Parkin), as well as the levels of oxidative stress mediators and proinflammatory cytokines. Alc treatment effectively ameliorated histopathological changes and metabolic abnormalities associated with T2DM. It downregulated pyroptosis-related proteins, upregulated mitophagy-related proteins, reduced proinflammatory cytokine levels, and attenuated oxidative stress. Treatment with Mdivi-1 suppressed the beneficial effects of Alc. Our findings highlight the therapeutic potential of Alc in managing DR by targeting multiple pathophysiological pathways, including pyroptosis, inflammation, and oxidative stress. The observed antipyroptotic effects of Alc were partially mediated by the activation of the PINK1/parkin-mediated mitophagy pathway. Additional studies are necessary to thoroughly understand the therapeutic mechanisms of Alc and its viability as a treatment choice for DR.

Alpha-lipoic acid enhances ischemic postconditioning-mediated improvement of myocardial infarction and apoptosis in diabetic rats with ischemia/reperfusion injury

This work evaluated the combined effects of alpha-lipoic acid (ALA) and ischemic postconditioning (Post) on myocardial infarction and cell death in rats with chronic type-II diabetes following ischemia/reperfusion injury. The rats received a high-fat diet and were given one intraperitoneal injection of 35 mg/kg streptozotocin to induce chronic diabetes. They were then pretreated with ALA (100 mg/kg/day, orally) for 5 weeks before undergoing ischemia/reperfusion (I/R) insult. The hearts experienced 35 min regional ischemia through ligating the left anterior descending coronary artery, followed by 60 min reperfusion. The Post protocol involved 6 cycles of a 10/10 s algorithm, applied during the early stage of reperfusion. The use of Post alone did not significantly alter lactate dehydrogenase and infarct size levels, while ALA showed positive effects. Similar findings were observed for apoptotic changes with single treatments. However, the concurrent administration of ALA and Post significantly reduced the protein expressions of Bax, Bax/Bcl2, and cleaved caspase-3 while increasing Bcl2 expression. Additionally, the histopathological findings of the combined therapy were superior to those of single treatments. The concomitant use of ALA and Post effectively inhibited apoptosis, leading to cardiac recovery after I/R injury in diabetic conditions. This strategy could improve outcomes for preserving diabetic hearts following I/R insults.

Reducing myocardial infarction by combination of irisin and Dendrobium nobile Lindl through inhibiting nod-like receptor protein-3-related pyroptosis and activating PINK1/Parkin-mitophagy during aging

Aging, a crucial risk factor for ischemic heart disease, has negative impacts on cardioprotective mechanisms. As such, there is still an unmet requirement to explore potential therapies for improving the outcomes of myocardial ischemia/reperfusion (IR) injury in elderly subjects. Here, we aimed to confirm the cardioprotective function of irisin/Dendrobium nobile Lindl (DNL) combination therapy against myocardial IR injury in aged rats, with a focus on the involvement of pyroptosis and mitophagy. Male aged Wistar rats (22-24 months old, 400-450 g; n = 54) underwent myocardial IR or sham surgery. Before IR operation, rats were pretreated with irisin (0.5 mg/kg, intraperitoneally) and/or DNL (80 mg/kg, orally) for 1 or 4 weeks, respectively, at corresponding groups. Cardiac function, lactate dehydrogenase (LDH) and cardiac-specific isoform of troponin-I (cTn-I) levels, the expression of proteins involved in pyroptosis (nod-like receptor protein-3 (NLRP3), apoptosis-associated speck-like protein, c-caspase-1, and GSDMD-N) and mitophagy (PINK1 and Parkin), and pro-inflammatory cytokines levels were evaluated after 24 h of reperfusion. Irisin/DNL combined therapy significantly restored cardiac function and decreased LDH and cTn-I levels. It also downregulated pyroptosis-related proteins, upregulated PINK1 and Parkin, and decreased pro-inflammatory cytokines secretion. Pretreatment with Mdivi-1, as mitophagy inhibitor, abolished the cardioprotective action of dual therapy. This study revealed the cardioprotective effects of irisin/DNL combination therapy against IR-induced myocardial injury in aged rats, and also showed that the mechanism might be associated with suppression of NLRP3-related pyroptosis through enhancing the activity of the PINK1/Parkin mitophagy. This combination therapy is worthy of further detailed studies due to its potential to alleviate myocardial IR injury upon aging.

Mitochondria-targeted combination treatment strategy counteracts myocardial reperfusion injury of aged rats by modulating autophagy and inflammatory response

BACKGROUND

Aging, as a recognized risk factor for ischemic heart disease, interferes with protective mechanisms and abolishes the optimal effectiveness of cardioprotective interventions, leading to the loss of cardioprotection following myocardial ischemia/reperfusion (I/R) injury. This study was designed to explore the possible interaction of aging with cardioprotection induced by combination therapy with coenzyme Q₁₀ (CoQ₁₀) and mitochondrial transplantation in myocardial I/R injury of aged rats.

METHODS

Male Wistar rats (n = 72, 400-450 g, 22-24 months old) were randomized into groups with/without I/R and/or CoQ₁₀ and mitochondrial transplantation, alone or in a combinational mode. An in vivo model of myocardial I/R injury was established by left anterior descending coronary artery occlusion and re-opening. Mitochondria were isolated from donor rats and injected intramyocardially (150 µl of the mitochondrial suspension containing 2 × 10⁵±0.3 × 10⁵ mitochondria) at the onset of reperfusion in recipient groups. CoQ₁₀ (20 mg/kg/day) was injected intramuscularly for 7 days before I/R operation. Lastly, myocardial function, cTn-I level, expression of autophagy-associated proteins (Beclin1, p62, and LC3-II/LC3-I), and the levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) were assessed.

RESULTS

Co-application of CoQ₁₀ and mitotherapy concomitantly improved myocardial function and decreased cTn-I level in aged reperfused hearts (P < .001). This combination therapy also modulated autophagic activity and decreased pro-inflammatory cytokines (P < .01 to P < .001). This combinational approach induced noticeable cardioprotection in comparison with monotherapies-received groups.

CONCLUSION

We found that combination of CoQ₁₀ and mitochondrial transplantation attenuated myocardial I/R injury in aged rats, in part by modulating autophagy and inflammatory response, hence, appears to restore aging-related loss of cardioprotection in aged patients.

Evaluation of the protective roles of alpha-lipoic acid supplementation on nanomaterial-induced toxicity: A meta-analysis of in vitro and in vivo studies

Extensive exposure to nanomaterials causes oxidative stress and inflammation in various organs and leads to an increased risk of adverse health outcomes; therefore, how to prevent the toxic effects are of great concern to human. Alpha-lipoic acid (ALA) has anti-oxidant and anti-inflammatory activities, suggesting it may be effective to prevent nanomaterial-induced toxicity. However, the results obtained in individual studies remained controversial. We aimed to comprehensively evaluate the effects of ALA supplementation on nanomaterial-induced toxicity by performing a meta-analysis. Databases of PubMed, EMBASE, and Cochrane Library were searched up to May 2022. STATA 15.0 software was used for statistical analysis. Twelve studies were included. Meta-analysis of eight in vivo studies showed ALA supplementation could exert significant effects on nanomaterial-induced oxidative stress (by reducing MDA, ROS and increasing GSH, CAT, GPx, and SOD), inflammation (by downregulating NO, IgG, TNF-α, IL-6, and CRP), apoptosis (by activation of pro-apoptotic caspase-3), DNA damage (by a reduction in the tail length) and organ damage (by a decrease in the liver biomarker ALT and increases in brain neuron biomarker AChE and heart biomarker CPK). Pooled analysis of four in vitro studies indicated ALA intervention increased cell viability, decreased ROS levels, inhibited cell apoptosis and chelated metal ions. Subgroup analyses revealed changing the levels of GSH, IL-6, and metal ions were the main protective mechanisms of ALA supplementation because they were not changed by any subgroup factors. In conclusion, ALA supplementation may represent a potential strategy for the prevention of the toxicity induced by nanomaterials.