Mitochondria in acute myocardial infarction and cardioprotection

Preadmission metformin use increased the incidence of hyperlactatemia at admission and 30-day in-hospital mortality among T2D patients with heart disease at high risk of hypoxia

BACKGROUND

Surprisingly, despite the high prevalence of metformin use in type 2 diabetes (T2D) patients with heart disease, limited safety data is available regarding metformin use in patients with acute and critical heart disease.

METHODS

In this single-center retrospective study, patients admitted to the cardiology department for heart failure (HF) or acute coronary syndrome (ACS) between December 2013 and December 2021 and who underwent arterial blood gas analysis at admission with an estimated glomerular clearance rate of ≥45 ml/min/1.73 m2 were identified. The incidences of hyperlactatemia, acidosis, and 30-day in-hospital mortality were compared between preadmission metformin users and nonusers.

RESULTS

Of 526 admissions, 193/193 metformin users/nonusers were selected in a propensity score-matched model. Metformin users had greater lactate levels (2.55 ± 2.07 mmol/l vs. 2.00 ± 1.80 mmol/l P < 0.01), a greater incidence of hyperlactatemia [odds ratio (OR) = 2.55; 95% confidence interval (CI), 1.63-3.98; P < 0.01] and acidosis (OR = 1.78; 95% CI, 1.00-3.16; P < 0.05) at admission and a greater incidence of in-hospital mortality (OR = 3.83; 95% CI, 1.05-13.94; P < 0.05), especially those with HF/acute myocardial infarction, elderly age, or without preadmission insulin use.

CONCLUSIONS

Our results suggest that, compared to metformin nonusers, preadmission use of metformin may be associated with a greater incidence of hyperlactatemia and acidosis at admission and greater 30-day in-hospital mortality among T2D patients with HF or ACS at high risk of hypoxia, particularly those without preadmission insulin use. The safety of metformin in this population needs to be confirmed in prospective controlled trials.

Inhibition of ubiquitin-specific protease 7 ameliorates ferroptosis-mediated myocardial infarction by contrasting oxidative stress: An in vitro and in vivo analysis

BACKGROUND

Our prior research determined that USP7 exacerbates myocardial injury. Additionally, existing studies indicate a strong connection between USP7 and ferroptosis. However, the influence of USP7 on ferroptosis-mediated myocardial infarction (MI) remains unclear. Given these findings, we are particularly interested in USP7's regulatory role in ferroptosis-mediated MI and its underlying mechanisms.

METHODS

In this study, we established MI models and lentivirus-transfected groups to inhibit USP7 expression both in vivo and in vitro. Cardiac function was detected with Echocardiography. TTC and HE staining were employed to assess myocardial alterations. The expression of ferroptosis markers (PTGS2, ACSL4, GPX4) were analyzed by RT-qPCR and Western blotting. Flow cytometry and ELISA were used for measuring Fe2+, lipid ROS, GSH, and GSSG levels. TEM and Prussian blue staining were used to observe mitochondrial alterations and iron deposition. RT-qPCR, Western blotting, and immunofluorescence were conducted to analyze Keap1, Nrf2, and nuclear Nrf2 expression in vitro and in vivo.

RESULTS

In the MI model group, USP7 expression significantly increased, worsening ferroptosis-mediated MI. Conversely, in the USP7-inhibited group, activation of the Keap1-Nrf2 signaling pathway improved ferroptosis-mediated MI outcomes. In vitro, the MI model exhibited a marked decline in cardiomyocyte viability and notable mitochondrial damage. However, these issues improved in the USP7-inhibited groups. In vivo, USP7 intensified MI and iron deposition within the MI model group, with decreased values of LVEF, LVFS, SV, LVAWd, and LVPWs, all of which showed improvement in the USP7-inhibited group, except for LVPWd and LVPWs, which showed no significant variation. Importantly, both the in vitro and in vivo experiments revealed analogous results: a reduction in Keap1 expression and an increase in both Nrf2 and nuclear Nrf2 post USP7 inhibition. Additionally, GPX4 expression decreased while PTGS2 and ACSL4 expressions increased. Notably, concentrations of Fe2+, lipid ROS, GSH, and GSSG significantly decreased.

CONCLUSION

In vitro and in vivo studies have found that inhibition of USP7 attenuates iron deposition and suppresses oxidative stress, resulting in amelioration of ferroptosis-induced MI.

Multifaceted role of dynamin-related protein 1 in cardiovascular disease: From mitochondrial fission to therapeutic interventions

Mitochondria are central to cellular energy production and metabolic regulation, particularly in cardiomyocytes. These organelles constantly undergo cycles of fusion and fission, orchestrated by key proteins like Dynamin-related Protein 1 (Drp-1). This review focuses on the intricate roles of Drp-1 in regulating mitochondrial dynamics, its implications in cardiovascular health, and particularly in myocardial infarction. Drp-1 is not merely a mediator of mitochondrial fission; it also plays pivotal roles in autophagy, mitophagy, apoptosis, and necrosis in cardiac cells. This multifaceted functionality is often modulated through various post-translational alterations, and Drp-1's interaction with intracellular calcium (Ca2 + ) adds another layer of complexity. We also explore the pathological consequences of Drp-1 dysregulation, including increased reactive oxygen species (ROS) production and endothelial dysfunction. Furthermore, this review delves into the potential therapeutic interventions targeting Drp-1 to modulate mitochondrial dynamics and improve cardiovascular outcomes. We highlight recent findings on the interaction between Drp-1 and sirtuin-3 and suggest that understanding this interaction may open new avenues for therapeutically modulating endothelial cells, fibroblasts, and cardiomyocytes. As the cardiovascular system increasingly becomes the focal point of aging and chronic disease research, understanding the nuances of Drp-1's functionality can lead to innovative therapeutic approaches.

Impact of Hemoglobin Level in Ex Vivo Heart Perfusion on Donation After Circulatory Death Hearts: A Juvenile Porcine Experimental Model

BACKGROUND

Ex vivo heart perfusion (EVHP) of donation after circulatory death (DCD) hearts has become an effective strategy in adults; however, the small circulating volume in pediatrics poses the challenge of a low-hemoglobin (Hb) perfusate. We aimed to determine the impact of perfusate Hb levels during EVHP on DCD hearts using a juvenile porcine model.

METHODS

Sixteen DCD piglet hearts (11-14 kg) were reperfused for 4 h in unloaded mode followed by working mode. Metabolism, cardiac function, and cell damage were compared between the low-Hb (Hb, 5.0-5.9 g/dL; n = 8) and control (Hb, 7.5-8.4 g/dL; n = 8) groups. Between-group differences were evaluated using 2-sample t -tests or Fisher's Exact tests.

RESULTS

During unloaded mode, the low-Hb group showed lower myocardial oxygen consumption ( P  < 0.001), a higher arterial lactate level ( P  = 0.001), and worse systolic ventricular function ( P  < 0.001). During working mode, the low-Hb group had a lower cardiac output (mean, 71% versus 106% of normal cardiac output, P  = 0.010) and a higher arterial lactate level ( P  = 0.031). Adjusted cardiac troponin-I ( P  = 0.112) did not differ between the groups. Morphological myocyte injury in the left ventricle was more severe in the low-Hb group ( P  = 0.028).

CONCLUSIONS

Low-Hb perfusate with inadequate oxygen delivery induced anaerobic metabolism, resulting in suboptimal DCD heart recovery and declined cardiac function. Arranging an optimal perfusate is crucial to organ protection, and further endeavors to refine the priming volume of EVHP or the transfusion strategy are required.

Proteolysis of mitochondrial calpain-13 in cerebral ischemia-reperfusion injury

Calpains are calcium-dependent cysteine proteases activated by intracellular Ca2+. Although calpains mainly exist in the cytosol, calpain-13 is present in the mitochondria in mouse brains; however, the enzymatic properties and physiological functions of calpain-13 remain unknown. Hence, in this study, we predicted and evaluated the enzymatic properties of calpain-13. Based on our bioinformatic approaches, calpain-13 possessed a catalytic triad and EF-hand domain, similar to calpain-1, a well-studied calpain. Therefore, we hypothesized that calpain-13 had calpain-1-like enzymatic properties; however, calpain-13 was not proteolyzed in C57BL/6J mouse brains. Subsequently, cerebral ischemia/reperfusion (I/R) injury caused proteolysis of mitochondrial calpain-13. Thus, our study showed that mitochondrial calpain-13 was proteolyzed in the mitochondria of the I/R injured mouse brain. This finding could be valuable in further research elucidating the involvement of calpain-13 in cell survival or death in brain diseases, such as cerebral infarction.

Zishenhuoxue decoction-induced myocardial protection against ischemic injury through TMBIM6-VDAC1-mediated regulation of calcium homeostasis and mitochondrial quality surveillance

BACKGROUND

Zishenhuoxue decoction (ZSHX), a Chinese herbal medicine, exhibits myocardial and vascular endothelial protective properties. The intricate regulatory mechanisms underlying myocardial ischemic injury and its association with dysfunctional mitochondrial quality surveillance (MQS) remain elusive.

HYPOTHESIS/PURPOSE

To study the protective effect of ZSHX on ischemic myocardial injury in mice using a TMBIM6 gene-modified animal model and mitochondrial quality control-related experiments.

STUDY DESIGN

Using model animals and myocardial infarction surgery-induced ischemic myocardial injury TMBIM6 gene-modified mouse models, the pharmacological activity of ZSHX in inhibiting ischemic myocardial injury and mitochondrial homeostasis disorder in vivo was tested.

METHODS

Our focal point entailed scrutinizing the impact of ZSHX on ischemic myocardial impairment through the prism of TMBIM6. This endeavor was undertaken utilizing mice characterized by heart-specific TMBIM6 knockout (TMBIM6CKO) and their counterparts, the TMBIM6 transgenic (TMBIM6TG) and VDAC1 transgenic (VDAC1TG) mice.

RESULTS

ZSHX demonstrated dose-dependent effectiveness in mitigating ischemic myocardial injury and enhancing mitochondrial integrity. TMBIM6CKO hindered ZSHX's cardio-therapeutic and mitochondrial protective effects, while ZSHX's benefits persisted in TMBIM6TG mice. TMBIM6CKO also blocked ZSHX's regulation of mitochondrial function in HR-treated cardiomyocytes. Hypoxia disrupted the MQS in cardiomyocytes, including calcium overload, excessive fission, mitophagy issues, and disrupted biosynthesis. ZSHX counteracted these effects, thereby normalizing MQS and inhibiting calcium overload and cardiomyocyte necroptosis. Our results also showed that hypoxia-induced TMBIM6 blockade resulted in the over-activation of VDAC1, a major mitochondrial calcium uptake pathway, while ZSHX could increase the expression of TMBIM6 and inhibit VDAC1-mediated calcium overload and MQS abnormalities.

CONCLUSIONS

Our findings suggest that ZSHX regulates mitochondrial calcium homeostasis and MQS abnormalities through a TMBIM6-VDAC1 interaction mechanism, which helps to treat ischemic myocardial injury and provides myocardial protection. This study also offers insights for the clinical translation and application of mitochondrial-targeted drugs in cardiomyocytess.

Safety and efficacy of platelet-derived mitochondrial transplantation in ischaemic heart disease

BACKGROUND

Acute ST-elevation myocardial infarction (STEMI) remains a globally significant health challenge in spite of improvement in management strategy. Being aware that mitochondrial dysfunction plays a crucial role in ischaemia-reperfusion injury (IRI) modulation, empirical evidence suggests functional mitochondrial transplantation strikes as a reliable therapeutic approach for patients with acute myocardial infarction.

METHODS AND RESULTS

We conducted a prospective, triple-blinded, parallel-group, blocked randomised clinical trial to investigate the therapeutic effects and clinical outcomes of platelet-derived mitochondrial transplantation in 30 patients with acute STEMI, such that the 15 subjects in the control group were given standard of care treatment, whereas the subjects in the intervention group received autologous platelet-derived mitochondria through the intracoronary injection. We observed that within 40 days, the intervention group had a slightly greater improvement in the left ventricular ejection fraction (LVEF) compared to the control group and experienced a significant enhancement in the exercise capacity (p < 0.001). Moreover, major adverse cardiac events (MACE), arrhythmia, fever, and tachycardia were compared between the groups and lack of significant difference marks the safety of mitochondrial transplantation (p > 0.05). Furthermore, the two groups were not significantly distinct as regards the average length of stay for a hospitalisation (p > 0.05).

CONCLUSION

We suggest platelet-derived mitochondrial transplantation appears as a beneficial and highly promising therapeutic option for patients of ischaemic heart disease (IHD); however, we are aware that further in-depth studies with larger sample sizes along with longer follow-up periods are necessary for validating the clinical implications of our findings.

Circular RNA Profile in Atherosclerotic Disease: Regulation during ST-Elevated Myocardial Infarction

Circular (circ) RNAs are non-coding RNAs with important functions in the nervous system, cardiovascular system, and cancer. Their role in atherosclerosis and myocardial infarction (MI) remains poorly described. We aim to investigate the potential circRNAs in immune cells during atherogenesis and examine the most regulated during MI and the modulation by interleukin (IL)-6 receptor inhibition by tocilizumab. Wild-type (WT) and ApoE-/- mice were fed an atherogenic diet for 10 weeks, and the circRNA profile was analyzed by circRNA microarray. Whole blood from patients with ST-elevated MI (STEMI) and randomized to tocilizumab (n = 21) or placebo (n = 19) was collected at admission, 3-7 days, and at 6 months, in addition to samples from healthy controls (n = 13). Primers for human circRNA were designed, and circRNA levels were measured using RT-qPCR. mRNA regulation of predicted circRNA targets was investigated by RNA sequencing. The expression of 867 circRNAs differed between atherogenic and WT mice. In STEMI patients, circUBAC2 was significantly lower than in healthy controls. CircANKRD42 and circUBAC2 levels were inversely correlated with troponin T, and for circUBAC2, an inverse correlation was also seen with final infarct size at 6 months. The predicted mRNA targets for circUBAC2 and circANKRD42 were investigated and altered levels of transcripts involved in the regulation of inflammatory/immune cells, apoptosis, and mitochondrial function were found. Finally, tocilizumab induced an up-regulation of circANKRD42 and circUBAC2 3-7 days after percutaneous coronary intervention. CircRNA levels were dysregulated in STEMI, potentially influencing the immune system, apoptosis, and mitochondrial function.

Corosolic acid attenuates cardiac ischemia/reperfusion injury through the PHB2/PINK1/parkin/mitophagy pathway

Despite advances in treatment, myocardial infarction remains the leading cause of heart failure and death worldwide, and the restoration of coronary blood flow can also cause heart damage. In this study, we found that corosolic acid (CA), also known as plant insulin, significantly protects the heart from ischemia-reperfusion (I/R) injury. In addition, CA can inhibit oxidative stress and improve mitochondrial structure and function in cardiomyocytes. Subsequently, our study demonstrated that CA improved the expression of the mitophagy-related proteins Prohibitin 2 (PHB2), PTEN-induced putative kinase protein-1 (PINK1), and Parkin. Meanwhile, through molecular docking, we found an excellent binding between CA and PHB2 protein. Finally, the knockdown of PHB2 eliminated the protective effect of CA on hypoxia-reoxygenation in cardiomyocytes. Taken together, our study reveals that CA increases mitophagy in cardiomyocytes via the PHB2/PINK1/Parkin signaling pathway, inhibits oxidative stress response, and maintains mitochondrial function, thereby improving cardiac function after I/R.

Chronic mitochondrial dynamic-targeted therapy alleviates left ventricular dysfunction by reducing multiple programmed cell death in post-myocardial infarction rats

Mitochondrial dysfunction and the activation of multiple programmed cell death (PCD) have been shown to aggravate the severity and mortality associated with the progression of myocardial infarction (MI). Although pharmacological modulation of mitochondrial dynamics, including treatment with the fusion promoter (M1) and the fission inhibitor (Mdivi-1), exerted cardioprotection against several cardiac complications, their roles in the post-MI model have never been investigated. Using a MI rat model instigated by permanent left-anterior descending (LAD) coronary artery occlusion, post-MI rats were randomly assigned to receive one of 4 treatments (n = 10/group): vehicle (DMSO 3%V/V), enalapril (10 mg/kg), Mdivi-1 (1.2 mg/kg) and M1 (2 mg/kg), while a control group of sham operated rats underwent surgery without LAD occlusion (n = 10). After 32-day treatment, cardiac and mitochondrial function, and histopathological morphology were investigated and molecular analysis was performed. Treatment with enalapril, Mdivi-1, and M1 significantly mitigated cardiac pathological remodeling, reduced myocardial injury, and improved left ventricular (LV) function in post-MI rats. Importantly, all interventions also attenuated mitochondrial dynamic imbalance and mitigated activation of apoptosis, necroptosis, and pyroptosis after MI. This investigation demonstrated for the first time that chronic mitochondrial dynamic-targeted therapy mitigated mitochondrial dysfunction and activation of PCD, leading to improved LV function in post-MI rats.

Puerarin attenuates myocardial ischemic injury and endoplasmic reticulum stress by upregulating the Mzb1 signal pathway

Objective

This study investigated the role of Mzb1 in puerarin protection against heart injury and dysfunction in acute myocardial infarction (AMI) mice.

Methods

C57BL/6 mice were pretreated with and without puerarin at doses of 50 mg/kg and 100 mg/kg for 14 days before establishing the AMI model. An AMI model was induced by ligating the left descending anterior coronary artery, and AC16 cardiomyocytes were treated with H2O2 in vitro. Echocardiography was performed to measure cardiac function. DHE staining, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase assay, and DCFH-DA oxidative fluorescence staining were used to determine reactive oxygen species (ROS) production in vivo and in vitro. Bioinformatics analysis was used to predict potential upstream transcription factors of Mzb1.

Results

Puerarin dose-dependently reduced myocardial infarction area and injury, accompanied by the improvement of cardiac function in AMI mice. AMI mice manifested an increase in myocardial oxidative stress, endoplasmic reticulum (ER) stress, apoptosis, and mitochondrial biogenesis dysfunction, which were inhibited by pretreatment with puerarin. Puerarin also prevented Mzb1 downregulation in the hearts of AMI mice or H2O2-treated AC16 cells. Consistent with the in vivo findings, puerarin inhibited H2O2-induced cardiomyocyte apoptosis, ER stress, and mitochondrial dysfunction, which were attenuated by siRNA Mzb1. Furthermore, the JASPAR website predicted that KLF4 may be a transcription factor for Mzb1. The expression of KLF4 was partially reversed by puerarin in the cardiomyocyte injury model, and KLF4 inhibitor (kenpaullone) inhibited Mzb1 expression and affected its function.

Conclusion

These results suggest that puerarin can protect against cardiac injury by attenuating oxidative stress and endoplasmic reticulum stress through upregulating the KLF4/Mzb1 pathway and that puerarin may expand our armamentarium for the prevention and treatment of ischemic heart diseases.

Xinyang tablet alleviated cardiac dysfunction in a cardiac pressure overload model by regulating the receptor-interacting serum/three-protein kinase 3/FUN14 domain containing 1-mediated mitochondrial unfolded protein response and mitophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Xinyang tablet (XYT) has been used for heart failure (HF) for over twenty years in clinical practice, but the underlying molecular mechanism remains poorly understood.

AIMS OF THE STUDY

In the present study, we aimed to explore the protective effects of XYT in HF in vivo and in vitro.

MATERIALS AND METHODS

Transverse aortic constriction was performed in vivo to establish a mouse model of cardiac pressure overload. Echocardiography, tissue staining, and real-time quantitative PCR (qPCR) were examined to evaluate the protective effects of XYT on cardiac function and structure. Adenosine 5'-triphosphate production, reactive oxygen species staining, and measurement of malondialdehyde and superoxide dismutase was used to detect mitochondrial damage. Mitochondrial ultrastructure was observed by transmission electron microscope. Immunofluorescence staining, qPCR, and Western blotting were performed to evaluate the effect of XYT on the mitochondrial unfolded protein response and mitophagy, and to identify its potential pharmacological mechanism. In vitro, HL-1 cells and neonatal mouse cardiomyocytes were stimulated with Angiotensin II to establish the cell model. Western blotting, qPCR, immunofluorescence staining, and flow cytometry were utilized to determine the effects of XYT on cardiomyocytes. HL-1 cells overexpressing receptor-interacting serum/three-protein kinase 3 (RIPK3) were generated by transfection of RIPK3-overexpressing lentiviral vectors. Cells were then co-treated with XYT to determine the molecular mechanisms.

RESULTS

In the present study, XYT was found to exerta protective effect on cardiac function and structure in the pressure overload mice. And it was also found XYT reduced mitochondrial damage by enhancing mitochondrial unfolded protein response and restoring mitophagy. Further studies showed that XYT achieved its cardioprotective role through regulating the RIPK3/FUN14 domain containing 1 (FUNDC1) signaling. Moreover, the overexpression of RIPK3 successfully reversed the XYT-induced protective effects and significantly attenuated the positive effects on the mitochondrial unfolded protein response and mitophagy.

CONCLUSIONS

Our findings indicated that XYT prevented pressure overload-induced HF through regulating the RIPK3/FUNDC1-mediated mitochondrial unfolded protein response and mitophagy. The information gained from this study provides a potential strategy for attenuating mitochondrial damage in the context of pressure overload-induced heart failure using XYT.

Analysis of the prognostic value of mitochondria-related genes in patients with acute myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) is a leading cause of death worldwide. Mitochondrial dysfunction is a key determinant of cell death post-AMI. Preventing mitochondrial dysfunction is thus a key therapeutic strategy. This study aimed to explore key genes and target compounds related to mitochondrial dysfunction in AMI patients and their association with major adverse cardiovascular events (MACE).

METHODS

Differentially expressed genes in AMI were identified from the Gene Expression Omnibus (GEO) datasets (GSE166780 and GSE24519), and mitochondria-related genes were obtained from MitoCarta3.0 database. By intersection of the two gene groups, mitochondria-related genes in AMI were identified. Next, the identified genes related to mitochondria were subject to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses. Protein-protein interaction (PPI) network was constructed, and key genes were screened. Then, targeted drug screening and molecular docking were performed. Blood samples from AMI patients and healthy volunteers were analyzed for the key genes expressions using quantitative real time polymerase chain reaction (qRT-PCR). Later, receiver operating characteristic (ROC) curves assessed the diagnostic value of key genes, and univariate and multivariate COX analyses identified risk factors and protective factors for MACE in AMI patients.

RESULTS

After screening and identification, 138 mitochondria-related genes were identified, mainly enriched in the processes and pathways of cellular respiration, redox, mitochondrial metabolism, apoptosis, amino acid and fatty acid metabolism. According to the PPI network, 5 key mitochondria-related genes in AMI were obtained: translational activator of cytochrome c oxidase I (TACO1), cytochrome c oxidase subunit Va (COX5A), PTEN-induced putative kinase 1 (PINK1), SURF1, and NDUFA11. Molecular docking showed that Cholic Acid, N-Formylmethionine interacted with COX5A, nicotinamide adenine dinucleotide + hydrogen (NADH) and NDUFA11. Subsequent basic experiments revealed that COX5A and NDUFA11 expressions were significantly lower in the blood of patients with AMI than those in the corresponding healthy volunteers; also, AMI patients with MACE had lower COX5A and NDUFA11 expressions in the blood than those without MACE (P < 0.01). ROC analysis also showed high diagnostic value for COX5A and NDUFA11 [area under the curve (AUC) > 0.85]. In terms of COX results, COX5A, NDUFA11 and left ventricular ejection fraction (LVEF) were protective factors for MACE in AMI, while C-reactive protein (CRP) was a risk factor.

CONCLUSION

COX5A and NDUFA11, key mitochondria-related genes in AMI, may be used as biomarkers to diagnose AMI and predict MACE.

Salvianolic acid B improves diabetic skin wound repair through Pink1/Parkin-mediated mitophagy

Diabetic skin wound is a disturbing and rapidly evolving clinical issue. Here, we investigated how salvianolic acid B (Sal B) affected the diabetic wound healing process. Following Sal B administration, histopathological damage was investigated by H&E and Masson staining, and CD34, apoptosis and mitophagy markers were measured by immunofluorescence, immunohistochemistry, and western blotting. Migration, proliferation, and mitochondrial function of high glucose (HG) -induced HMEC-1 cells were measured. The effects of si-Parkin on endothelial cell migration, apoptosis and mitochondrial autophagy were examined. Sal B alleviated inflammatory cell infiltration and promoted angiogenesis in skin wound tissue. Apoptosis and mitophagy were ameliorated by Sal B in diabetic skin wound tissues and HG-induced HMEC-1 cells. Parkin inhibition impaired the migratorypromoted cell apoptosis and inhibited mitophagy of HMEC-1 cells. This finding demonstrated that Sal B promoted diabetic skin wound repair via Pink1/Parkin-mediated mitophagy, improved our understanding of the diabetic wound healing process.

Is There a Mitochondrial Protection via Remote Ischemic Conditioning in Settings of Anticancer Therapy Cardiotoxicity?

PURPOSE OF REVIEW

To provide an overview of (a) protective effects on mitochondria induced by remote ischemic conditioning (RIC) and (b) mitochondrial damage caused by anticancer therapy. We then discuss the available results of studies on mitochondrial protection via RIC in anticancer therapy-induced cardiotoxicity.

RECENT FINDINGS

In three experimental studies in healthy mice and pigs, there was a RIC-mediated protection against anthracycline-induced cardiotoxicity and there was some evidence of improved mitochondrial function with RIC. The RIC-mediated protection was not confirmed in the two available studies in cancer patients. In adult cancer patients, RIC was associated with an adverse outcome. There are no data on mitochondrial function in cancer patients. Studies in tumor-bearing animals are needed to determine whether RIC does not interfere with the anticancer properties of the drugs and whether RIC actually improves mitochondrial function, ultimately resulting in improved cardiac function.

Mitochondrial outer membrane protein Samm50 protects against hypoxia-induced cardiac injury by interacting with Shmt2

Cardiac remodeling is a critical process following myocardial infarction (MI), potentially leading to heart failure if untreated. The significance of mitochondrial homeostasis in MI remains insufficiently understood. Samm50 is an essential component of mitochondria. Our study aimed to investigate its role in hypoxia-induced cardiac injury and the underlying mechanisms. First, we observed that Samm50 was dynamically downregulated in mice with MI compared to the control mice. In vitro, Samm50 was also downregulated in oxygen-glucose-deprived neonatal rat cardiomyocytes and fibroblasts. Overexpression and knockdown of Samm50 mitigated and exacerbated cardiac apoptosis and fibrosis, while also improving and worsening mitochondrial homeostasis, respectively. Protein interactions with Samm50 during the protective process were identified via immune-coprecipitation/mass spectroscopy. Mechanistically, serine hydroxymethyltransferase 2 (Shmt2) interacted with Samm50, acting as a crucial element in the protective process by hindering the transfer of Bax from the cytoplasm to the mitochondria and subsequent activation of caspase-3. Inhibition of Shmt2 diminished the protective effect of Samm50 overexpression against cardiac injury. Finally, Samm50 overexpression in vivo mitigated cardiac remodeling and enhanced cardiac function in both acute and chronic MI. In conclusion, Samm50 overexpression mitigated hypoxia-induced cardiac remodeling by inhibiting apoptosis and fibrosis, with Shmt2 acting as a key regulator in this protective process. The Samm50/Shmt2 axis represents a newly discovered mitochondria-related pathway for mitigating hypoxia-induced cardiac injury.

Identification and Validation of Diagnostic Model Based on Angiogenesis- and Epithelial Mesenchymal Transition-Related Genes in Myocardial Infarction

Background

Myocardial infarction (MI) is a chronic cardiovascular disease. This study aims to discern potentially angiogenesis- and epithelial mesenchymal transition (EMT)-related genes as biomarkers for MI diagnosis through bioinformatics.

Methods

All datasets and angiogenesis- and EMT-related genes were collected from the public database. The differentially expressed genes (DEGs) of MI and MI-related genes were acquired. DEGs, MI-related genes, and angiogenesis- and EMT-related genes were intersected to obtain hub genes. Functional enrichment, immune microenvironment, and transcription factors (TFs)-hub genes regulatory network analysis were performed. The diagnostic markers and models were developed and validated. Drug prediction and molecular docking were performed. Finally, diagnostic markers expressions were validated using RT-qPCR.

Results

A total of 224 angiogenesis- and EMT-related genes, 2,897 DEGs, 1,217 MI-related genes, and 9 hub genes were acquired. The immune infiltration levels of plasma cells, T cells CD4 memory activated, monocytes, macrophages M0, mast cells resting, and neutrophils were higher in patients with MI. LRPAP1, COLGALT1, QSOX1, THBD, VCAN, PLOD1, and PLAUR as the diagnostic markers were identified and used to construct diagnostic models, which can distinguish MI from controls well. Then, 9 drugs were screened, and the binding energies ranged from -7.08 to -5.21 kcal/mol. RT-qPCR results showed that the expression of LRPAP1, PLAUR, and PLOD1 was significantly increased in the MI group.

Conclusion

The 7 diagnostic markers may play potential roles in MI and could contribute to improved future diagnostics.

Copper-loaded Milk-Protein Derived Microgel Preserves Cardiac Metabolic Homeostasis After Myocardial Infarction

Myocardial Infarction (MI) is a leading cause of death worldwide. Metabolic modulation is a promising therapeutic approach to prevent adverse remodeling after MI. However, whether material-derived cues can treat MI through metabolic regulation is mainly unexplored. Herein, a Cu2+ loaded casein microgel (CuCMG) aiming to rescue the pathological intramyocardial metabolism for MI amelioration is developed. Cu2+ is an important ion factor involved in metabolic pathways, and intracardiac copper drain is observed after MI. It is thus speculated that intramyocardial supplementation of Cu2+ can rescue myocardial metabolism. Casein, a milk-derived protein, is screened out as Cu2+ carrier through molecular-docking based on Cu2+ loading capacity and accessibility. CuCMGs notably attenuate MI-induced cardiac dysfunction and maladaptive remodeling, accompanied by increased angiogenesis. The results from unbiased transcriptome profiling and oxidative phosphorylation analyses support the hypothesis that CuCMG prominently rescued the metabolic homeostasis of myocardium after MI. These findings enhance the understanding of the design and application of metabolic-modulating biomaterials for ischemic cardiomyopathy therapy.

Glycogen synthase kinase-3β: A multifaceted player in ischemia-reperfusion injury and its therapeutic prospects

Ischemia-reperfusion injury (IRI) results in irreversible metabolic dysfunction and structural damage to tissues or organs, posing a formidable challenge in the field of organ implantation, cardiothoracic surgery, and general surgery. Glycogen synthase kinase-3β (GSK-3β) a multifunctional serine/threonine kinase, is involved in a variety of biological processes, including cell proliferation, apoptosis, and immune response. Phosphorylation of its tyrosine 216 and serine 9 sites positively and negatively regulates the activation and inactivation of the enzyme. Significantly, inhibition or inactivation of GSK-3β provides protection against IRI, making it a viable target for drug development. Though numerous GSK-3β inhibitors have been identified to date, the development of therapeutic treatments remains a considerable distance away. In light of this, this review summarizes the complicated network of GSK-3β roles in IRI. First, we provide an overview of GSK-3β's basic background. Subsequently, we briefly review the pathological mechanisms of GSK-3β in accelerating IRI, and highlight the latest progress of GSK-3β in multiorgan IRI, encompassing heart, brain, kidney, liver, and intestine. Finally, we discuss the current development of GSK-3β inhibitors in various organ IRI, offering a thorough and insightful reference for GSK-3β as a potential target for future IRI therapy.

VENOARTERIAL EXTRACORPOREAL MEMBRANE OXYGENATION REDUCES MYOCARDIAL AND MITOCHONDRIAL DAMAGE IN ACUTE MYOCARDIAL INFARCTION

ABSTRACT

Background: Myocardial infarction (MI) is a common cardiovascular disease with a high fatality rate once accompanied by cardiogenic shock. The efficacy of extracorporeal membrane oxygenation (ECMO) in treating MI is controversial. Methods: MI was induced by ligating the left anterior descending artery (LAD) in adult male rats. Groups were defined as follows: MI group, reperfusion for 90 min after 30 min of LAD occlusion; MI + ECMO group, reperfusion and ECMO were performed for 90 min immediately after 30 min of LAD occlusion; prolonged MI + ECMO group, ECMO was used immediately after 30 min of occlusion with persistent occlusion of the LAD for an additional 30 min, followed by 90 min of reperfusion. The myocardial infarct size and mitochondrial morphology and function data were collected and compared of each group. Results: The ECMO groups had a smaller myocardial infarct size and larger percentage ejection fraction. Compared with the prolonged MI + ECMO group, the immediate reperfusion group had a lower percentage of infarct size (63.28% vs. 17.97% vs. 31.22%, MI vs. MI + ECMO vs. prolonged MI + ECMO). Mitochondria isolated from the ischemic zone showed an intact mitochondrial structure, including fewer voids and broken cristae, and preserved activity of mitochondrial complex II and complex IV in ECMO groups. Conclusions: ECMO support in MI can reduce myocardial injury despite delayed coronary reperfusion.

Novel roles of κ-opioid receptor in myocardial ischemia-reperfusion injury

Acute heart attack is the primary cause of cardiovascular-related death worldwide. A common treatment is reperfusion of ischemic tissue, which can cause irreversible damage to the myocardium. The number of mitochondria in cardiomyocytes is large, which generate adenosine triphosphate (ATP) to sustain proper cardiac contractile function, and mitochondrial dysfunction plays a crucial role in cell death during myocardial ischemia-reperfusion, leading to an increasing number of studies investigating the impact of mitochondria on ischemia-reperfusion injury. The disarray of mitochondrial dynamics, excessive Ca2+ accumulation, activation of mitochondrial permeable transition pores, swelling of mitochondria, ultimately the death of cardiomyocyte are the consequences of ischemia-reperfusion injury. κ-opioid receptors can alleviate mitochondrial dysfunction, regulate mitochondrial dynamics, mitigate myocardial ischemia-reperfusion injury, exert protective effects on myocardium. The mechanism of κ-OR activation during myocardial ischemia-reperfusion to regulate mitochondrial dynamics and reduce myocardial ischemia-reperfusion injury will be discussed, so as to provide theoretical basis for the protection of ischemic myocardium.

Comparative effectiveness of myocardial patches and intramyocardial injections in treating myocardial infarction with a MitoQ/hydrogel system

In cardiac tissue engineering, myocardial surface patches and hydrogel intramyocardial injections represent the two primary hydrogel-based strategies for myocardial infarction (MI) treatment. However, the comparative effectiveness of these two treatments remains uncertain. Therefore, this study aimed to compare the effects of the two treatment modalities by designing a simple and reproducible hydrogel cross-linked with γ-PGA and 4-arm-PEG-SG. To improve mitochondrial damage in cardiomyocytes (CMs) during early MI, we incorporated the mitochondria-targeting antioxidant MitoQ into the hydrogel network. The hydrogel exhibited excellent biodegradability, biocompatibility, adhesion, and injectability in vitro. The hydrogel was utilized for rat MI treatment through both patch adhesion and intramyocardial injections. In vivo results demonstrated that the slow release of MitoQ peptide from the hydrogel hindered ROS production in CM, alleviated mitochondrial damage, and enhanced CM activity within 7 days, effectively inhibiting MI progression. Both hydrogel intramyocardial injections and patches exhibited positive therapeutic effects, with intramyocardial injections demonstrating superior efficacy in terms of cardiac function and structure in equivalent treatment cycles. In conclusion, we developed a MitoQ/hydrogel system that is easily prepared and can serve as both a myocardial patch and an intramyocardial injection for MI treatment, showing significant potential for clinical applications.

The roles of Th cells in myocardial infarction

Myocardial infarction, commonly known as a heart attack, is a serious condition caused by the abrupt stoppage of blood flow to a part of the heart, leading to tissue damage. A significant aspect of this condition is reperfusion injury, which occurs when blood flow is restored but exacerbates the damage. This review first addresses the role of the innate immune system, including neutrophils and macrophages, in the cascade of events leading to myocardial infarction and reperfusion injury. It then shifts focus to the critical involvement of CD4+ T helper cells in these processes. These cells, pivotal in regulating the immune response and tissue recovery, include various subpopulations such as Th1, Th2, Th9, Th17, and Th22, each playing a unique role in the pathophysiology of myocardial infarction and reperfusion injury. These subpopulations contribute to the injury process through diverse mechanisms, with cytokines such as IFN-γ and IL-4 influencing the balance between tissue repair and injury exacerbation. Understanding the interplay between the innate immune system and CD4+ T helper cells, along with their cytokines, is crucial for developing targeted therapies to mitigate myocardial infarction and reperfusion injury, ultimately improving outcomes for cardiac patients.

Double-Edged Sword: Exploring the Mitochondria-Complement Bidirectional Connection in Cellular Response and Disease

Mitochondria serve an ultimate purpose that seeks to balance the life and death of cells, a role that extends well beyond the tissue and organ systems to impact not only normal physiology but also the pathogenesis of diverse diseases. Theorized to have originated from ancient proto-bacteria, mitochondria share similarities with bacterial cells, including their own circular DNA, double-membrane structures, and fission dynamics. It is no surprise, then, that mitochondria interact with a bacterium-targeting immune pathway known as a complement system. The complement system is an ancient and sophisticated arm of the immune response that serves as the body's first line of defense against microbial invaders. It operates through a complex cascade of protein activations, rapidly identifying and neutralizing pathogens, and even aiding in the clearance of damaged cells and immune complexes. This dynamic system, intertwining innate and adaptive immunity, holds secrets to understanding numerous diseases. In this review, we explore the bidirectional interplay between mitochondrial dysfunction and the complement system through the release of mitochondrial damage-associated molecular patterns. Additionally, we explore several mitochondria- and complement-related diseases and the potential for new therapeutic strategies.

Calcium signaling from sarcoplasmic reticulum and mitochondria contact sites in acute myocardial infarction

Acute myocardial infarction (AMI) is a serious condition that occurs when part of the heart is subjected to ischemia episodes, following partial or complete occlusion of the epicardial coronary arteries. The resulting damage to heart muscle cells have a significant impact on patient's health and quality of life. About that, recent research focused on the role of the sarcoplasmic reticulum (SR) and mitochondria in the physiopathology of AMI. Moreover, SR and mitochondria get in touch each other through multiple membrane contact sites giving rise to the subcellular region called mitochondria-associated membranes (MAMs). MAMs are essential for, but not limited to, bioenergetics and cell fate. Disruption of the architecture of these regions occurs during AMI although it is still unclear the cause-consequence connection and a complete overview of the pathological changes; for sure this concurs to further damage to heart muscle. The calcium ion (Ca2+) plays a pivotal role in the pathophysiology of AMI and its dynamic signaling between the SR and mitochondria holds significant importance. In this review, we tried to summarize and update the knowledge about the roles of these organelles in AMI from a Ca2+ signaling point of view. Accordingly, we also reported some possible cardioprotective targets which are directly or indirectly related at limiting the dysfunctions caused by the deregulation of the Ca2+ signaling.

Ultrasound‑targeted microbubble destruction technology delivering β‑klotho to the heart enhances FGF21 sensitivity and attenuates heart remodeling post‑myocardial infarction

Fibroblast growth factor (FGF)21 is a peptide hormone that improves mitochondrial function and energy metabolism, and the deficiency of its co‑receptor β‑klotho (KLB) causes decreased FGF21 sensitivity. The present study examined whether the cardiac delivery of plasmids containing the KLB gene via ultrasound‑targeted microbubble destruction (UTMD) enhances the efficacy of FGF21 against heart failure post‑acute myocardial infarction (AMI). For this purpose, the levels of FGF21 in patients and rats with heart dysfunction post‑infarction were determined using ELISA. Sprague‑Dawley rats received the 3X UTMD‑mediated delivery of KLB@cationic microbubbles (KLB@CMBs) 1 week following the induction of AMI. Echocardiography, histopathology and biochemical analysis were performed at 4 weeks following the induction of AMI. The results revealed that patients with heart failure post‑infarction had higher serum FGF21 levels than the healthy controls. However, the downstream signal, KLB, but not α‑klotho, was reduced in the heart tissues of rats with AMI. As was expected, treatment with FGF21 did not substantially attenuate heart remodeling post‑infarction. It was found that decreased receptors KLB in the heart may result in the insensitivity to FGF21 treatment. In vivo, the UTMD technology‑mediated delivery of KLB@CMBs to the heart significantly enhanced the effects of FGF21 administration on cardiac remodeling and mitochondrial dysfunction in the rats following infarction. The delivery of KLB to the heart by UTMD and the administration of FGF21 attenuated mitochondrial impairment and oxidative stress by activating nuclear factor erythroid 2‑related factor 2 signals. On the whole, the present study demonstrates that the cardiac delivery of KLB significantly optimizes the cardioprotective effects of FGF21 therapy on adverse heart remodeling. UTMD appears a promising interdisciplinary approach with which to improve heart failure post‑myocardial infarction.

Mitochondrial quality control in human health and disease

Mitochondria, the most crucial energy-generating organelles in eukaryotic cells, play a pivotal role in regulating energy metabolism. However, their significance extends beyond this, as they are also indispensable in vital life processes such as cell proliferation, differentiation, immune responses, and redox balance. In response to various physiological signals or external stimuli, a sophisticated mitochondrial quality control (MQC) mechanism has evolved, encompassing key processes like mitochondrial biogenesis, mitochondrial dynamics, and mitophagy, which have garnered increasing attention from researchers to unveil their specific molecular mechanisms. In this review, we present a comprehensive summary of the primary mechanisms and functions of key regulators involved in major components of MQC. Furthermore, the critical physiological functions regulated by MQC and its diverse roles in the progression of various systemic diseases have been described in detail. We also discuss agonists or antagonists targeting MQC, aiming to explore potential therapeutic and research prospects by enhancing MQC to stabilize mitochondrial function.

Investigating the Therapeutic Effects of Ferroptosis on Myocardial Ischemia-Reperfusion Injury Using a Dual-Locking Mitochondrial Targeting Strategy

Research on ferroptosis in myocardial ischemia/reperfusion injury (MIRI) using mitochondrial viscosity as a nexus holds great promise for MIRI therapy. However, high-precision visualisation of mitochondrial viscosity remains a formidable task owing to the debilitating electrostatic interactions caused by damaged mitochondrial membrane potential. Herein, we propose a dual-locking mitochondria-targeting strategy that incorporates electrostatic forces and probe-protein molecular docking. Even in damaged mitochondria, stable and precise visualisation of mitochondrial viscosity in triggered and medicated MIRI was achieved owing to the sustained driving forces (e.g., pi-cation, pi-alkyl interactions, etc.) between the developed probe, CBS, and the mitochondrial membrane protein. Moreover, complemented by a western blot, we confirmed that ferrostatin-1 exerts its therapeutic effect on MIRI by improving the system xc-/GSH/GPX4 antioxidant system, confirming the therapeutic value of ferroptosis in MIRI. This study presents a novel strategy for developing robust mitochondrial probes, thereby advancing MIRI treatment.

Magnesium implantation as a continuous hydrogen production generator for the treatment of myocardial infarction in rats

Molecular hydrogen is an emerging broad-spectrum antioxidant molecule that can be used to treat myocardial infarction (MI). However, with hydrogen inhalation, the concentration that can be reached within target organs is low and the duration of action is short, which makes it difficult to achieve high dose targeted delivery of hydrogen to the heart, seriously limiting the therapeutic potential of hydrogen for MI. As a result of reactions with the internal environment of the body, subcutaneous implantation of magnesium slices leads to continuous endogenous hydrogen production, leading to a higher hydrogen concentration and a longer duration of action in target organs. In this study, we propose magnesium implant-based hydrogen therapy for MI. After subcutaneous implantation of magnesium slices in the dorsum of rats, we measured hydrogen production and efficiency, and evaluated the safety of this approach. Compared with hydrogen inhalation, it significantly improved cardiac function in rats with MI. Magnesium implantation also cleared free radicals that were released as a result of mitochondrial dysfunction, as well as suppressing cardiomyocyte apoptosis.

Targeting the PANoptosis signaling pathway for myocardial protection: therapeutic potential of Xian Ling Gu Bao capsule

Introduction: Myocardial infarction (MI), the most prevalent ischemic heart disease, constitutes a primary cause of global cardiovascular disease with incidence and mortality. The pathogenesis of MI is exceedingly intricate, with PANoptosis playing a pivotal role in its pathological process. Xian Ling Gu Bao capsule (XLGB) contains various active components, including flavonoids, terpenes, and phenylpropanoids, and exhibits a wide range of pharmacological activities. However, it remains unclear whether XLGB can protect the myocardium from damage after MI. This study aimed to investigate the impact of XLGB on isoprenaline (ISO)-induced MI in mice and its potential mechanisms. Methods: This study assessed the protective effects of XLGB against ISO-induced MI through techniques such as echocardiography, HE staining, Masson staining, and enzyme-linked immunosorbent assay (ELISA). Furthermore, the potential mechanisms of XLGB's protective effects on MI were explored using bioinformatics, molecular docking, and molecular dynamics simulations. These mechanisms were further validated through immunofluorescence staining and Western blotting. Results: The results demonstrated that various doses of XLGB exhibited a significant reduction in myocardial injury induced by myocardial infarction. Intriguingly, higher dosages of XLGB displayed superior therapeutic efficacy compared to the positive control metoprolol. This protective effect is primarily achieved through the inhibition of oxidative stress and the inflammatory processes. Furthermore, we have elucidated that XLGB protected the myocardium from MI-induced damage by suppressing PANoptosis, with a critical role played by the NLRP3/Caspase3/RIP1 signaling pathway. Of particular note, the primary compounds of XLGB were found to directly interact with NLRP3/Caspase3/RIP1, a discovery further validated through molecular docking and molecular dynamics simulations. This suggests that NLRP3/Caspase3/RIP1 may be a therapeutic target for XLGB-induced myocardial protection. Conclusion: In summary, our findings reveal a novel property of XLGB: reverses myocardial damage following MI by inhibiting the NLRP3/Caspase3/RIP1-mediated PANoptosis pathway.

Resveratrol protects against myocardial ischemic injury in obese mice via activating SIRT3/FOXO3a signaling pathway and restoring redox homeostasis

BACKGROUND

Increasing global overweight and obesity rates not only increase the prevalence of myocardial infarction (MI), but also exacerbate ischemic injury and result in worsened prognosis. Currently, there are no drugs that can reverse myocardial damage once MI has occurred, therefore discovering drugs that can potentially limit the extent of ischemic damage to the myocardium is critical. Resveratrol is a polyphenol known for its antioxidant properties, however whether prolonged daily intake of resveratrol during obesity can protect against MI-induced damage remains unexplored.

METHODS

We established murine models of obesity via high-fat/high-fructose diet, along with daily administrations of resveratrol or vehicle, then performed surgical MI to examine the effects and mechanisms of resveratrol in protecting against myocardial ischemic injury.

RESULTS

Daily administration of resveratrol in obese mice robustly protected against myocardial ischemic injury and improved post-MI cardiac function. Resveratrol strongly inhibited oxidative and DNA damage via activating SIRT3/FOXO3a-dependent antioxidant enzymes following MI, which were completely prevented upon administration of 3-TYP, a selective SIRT3 inhibitor. Hence, the cardioprotective effects of prolonged resveratrol intake in protecting obese mice against myocardial ischemic injury was due to reestablishment of intracellular redox homeostasis through activation of SIRT3/FOXO3a signaling pathway.

CONCLUSION

Our findings provide important new evidence that supports the daily intake of resveratrol, especially in those overweight or obese, which can robustly decrease the extent of ischemic damage following MI. Our study therefore provides new mechanistic insight and suggests the therapeutic potential of resveratrol as an invaluable drug in the treatment of ischemic heart diseases.

Mitochondrial Kinase Signaling for Cardioprotection

Myocardial ischemia/reperfusion injury is reduced by cardioprotective adaptations such as local or remote ischemic conditioning. The cardioprotective stimuli activate signaling cascades, which converge on mitochondria and maintain the function of the organelles, which is critical for cell survival. The signaling cascades include not only extracellular molecules that activate sarcolemmal receptor-dependent or -independent protein kinases that signal at the plasma membrane or in the cytosol, but also involve kinases, which are located to or within mitochondria, phosphorylate mitochondrial target proteins, and thereby modify, e.g., respiration, the generation of reactive oxygen species, calcium handling, mitochondrial dynamics, mitophagy, or apoptosis. In the present review, we give a personal and opinionated overview of selected protein kinases, localized to/within myocardial mitochondria, and summarize the available data on their role in myocardial ischemia/reperfusion injury and protection from it. We highlight the regulation of mitochondrial function by these mitochondrial protein kinases.

A causal association between amyotrophic lateral sclerosis and atrial fibrillation: a two-sample Mendelian randomization study

Objectives

To look into the connection between amyotrophic lateral sclerosis (ALS) and atrial fibrillation (AF) using Mendelian randomization (MR).

Methods

Two-sample MR was performed using genetic information from genome-wide association studies (GWAS). Genetic variants robustly associated with ALS and AF were used as instrumental variables. GWAS genetic data for ALS (n = 138,086, ncase = 27,205) and AF (n = 1,030,836, ncase = 60,620), publicly available from IEU Open. The specific MR protocols were Inverse variance-weighted (IVW), Simple mode, MR Egger, Weighted mode, and Weight median estimator (WME). Subsequently, the MR-Egger intercept and Cochran Q examine were used to evaluate instrumental variables (IVs)' heterogeneity and multiplicative effects (IVs). In addition, MR-PRESSO analysis was conducted to exclude any potential pleiotropy.

Results

The IVW method demonstrated that ALS positively affected AF [OR: 1.062, 95% CI (1.004-1.122); P = 0.035]. Indeed, other MR methods were in accordance with the tendency of the IVW method (all OR > 1), and sensitivity testing verified the reliability of this MR result.

Conclusions

This MR study proves a positive causal connection between ALS and atrial fibrillation. Further studies are warranted to elucidate the mechanisms linking ALS and AF.

Identification of important genes related to anoikis in acute myocardial infarction

Acute myocardial infarction (AMI) increasingly precipitates severe heart failure, with diagnoses now extending to progressively younger demographics. The focus of this study was to pinpoint critical genes linked to both AMI and anoikis, thereby unveiling potential novel biomarkers for AMI detection and intervention. Differential analysis was performed to identify significant differences in expression, and gene functionality was explored. Weighted gene coexpression network analysis (WGCNA) was used to construct gene coexpression networks. Immunoinfiltration analysis quantified immune cell abundance. Protein-protein interaction (PPI) analysis identified the proteins that interact with theanoikis. MCODE identified key functional modules. Drug enrichment analysis identified relevant compounds explored in the DsigDB. Through WGCNA, 13 key genes associated with anoikis and differentially expressed genes were identified. GO and KEGG pathway enrichment revealed the regulation of apoptotic signalling pathways and negative regulation of anoikis. PPI network analysis was also conducted, and 10 hub genes, such as IL1B, ZAP70, LCK, FASLG, CD4, LRP1, CDH2, MERTK, APOE and VTN were identified. IL1B were correlated with macrophages, mast cells, neutrophils and Tcells in MI, and the most common predicted medications were roxithromycin, NSC267099 and alsterpaullone. This study identified key genes associated with AMI and anoikis, highlighting their role in immune infiltration, diagnosis and medication prediction. These findings provide valuable insights into potential biomarkers and therapeutic targets for AMI.

Investigation of neuroprotective and therapeutic effects of cannabidiol in an acute coronary syndrome model

PURPOSE

The ischemia-reperfusion (I/R) injury seen in the heart can cause severe damage to essential organs such as the brain. Cannabidiol (CBD) obtained from Cannabis sativa is used today to treat various diseases. This study aimed to demonstrate CBD's neuroprotective and therapeutic properties in rats with brain damage caused by I/R in the heart.

MATERIALS

Rats were divided into four groups; sham, I/R, I/R + Prophylactic CBD, and I/R + Therapeutic CBD. End of the experiment, brain tissues were collected for biochemical, histopathological, and genetic examinations.

RESULTS

I/R damage increased the number of degenerative neurons, caspase-3 and TNF-α immunoexpression, total oxidant status levels, and oxidative stress index. Both prophylactic and therapeutic CBD administration reduced these increased values. In addition, the relative fold changes of AMPK, PGC-1α, SIRT1, and Bcl 2 decreased in the I/R group, and the relative fold change of Bax increased, which are indicators of ER stress and apoptosis. Both administrations of CBD reversed these genes' relative fold changes.

CONCLUSION

CBD can be protective against brain injury caused by cardiac I/R damage through antioxidant, anti-inflammatory, and anti-apoptotic mechanisms.

Vitamin C as Scavenger of Reactive Oxygen Species during Healing after Myocardial Infarction

Currently, coronary artery bypass and reperfusion therapies are considered the gold standard in long-term treatments to restore heart function after acute myocardial infarction. As a drawback of these restoring strategies, reperfusion after an ischemic insult and sudden oxygen exposure lead to the exacerbated synthesis of additional reactive oxidative species and the persistence of increased oxidation levels. Attempts based on antioxidant treatment have failed to achieve an effective therapy for cardiovascular disease patients. The controversial use of vitamin C as an antioxidant in clinical practice is comprehensively systematized and discussed in this review. The dose-dependent adsorption and release kinetics mechanism of vitamin C is complex; however, this review may provide a holistic perspective on its potential as a preventive supplement and/or for combined precise and targeted therapeutics in cardiovascular management therapy.

Cardiomyocyte maturation alters molecular stress response capacities and determines cell survival upon mitochondrial dysfunction

Cardiomyocyte maturation during pre- and postnatal development requires multiple intertwined processes, including a switch in energy generation from glucose utilization in the embryonic heart towards fatty acid oxidation after birth. This is accompanied by a boost in mitochondrial mass to increase capacities for oxidative phosphorylation and ATP generation required for efficient contraction. Whether cardiomyocyte differentiation is paralleled by augmented capacities to deal with reactive oxygen species (ROS), physiological byproducts of the mitochondrial electron transport chain (ETC), is less clear. Here we show that expression of genes and proteins involved in redox homeostasis and protein quality control within mitochondria increases after birth in the mouse and human heart. Using primary embryonic, neonatal and adult mouse cardiomyocytes in vitro we investigated how excessive ROS production induced by mitochondrial dysfunction affects cell survival and stress response at different stages of maturation. Embryonic and neonatal cardiomyocytes largely tolerate inhibition of ETC complex III by antimycin A (AMA) as well as ATP synthase (complex V) by oligomycin but are susceptible to complex I inhibition by rotenone. All three inhibitors alter the intracellular distribution and ultrastructure of mitochondria in neonatal cardiomyocytes. In contrast, adult cardiomyocytes treated with AMA undergo rapid morphological changes and cellular disintegration. At the molecular level embryonic cardiomyocytes activate antioxidative defense mechanisms, the integrated stress response (ISR) and ER stress but not the mitochondrial unfolded protein response upon complex III inhibition. In contrast, adult cardiomyocytes fail to activate the ISR and antioxidative proteins following AMA treatment. In conclusion, our results identified fundamental differences in cell survival and stress response in differentiated compared to immature cardiomyocytes subjected to mitochondrial dysfunction. The high stress tolerance of immature cardiomyocytes might allow outlasting unfavorable intrauterine conditions thereby preventing fetal or perinatal heart disease and may contribute to the regenerative capacity of the embryonic and neonatal mammalian heart.

Mitochondria-loaded alginate-based hydrogel accelerated angiogenesis in a rat model of acute myocardial infarction

Here, mitochondria were isolated from mesenchymal stem cells (MSCs) after being treated with mitochondria-stimulating substrates, 50 μM metformin (Met), and 40 μM dichloroacetic acid (DCA). The isolated mitochondria (2 × 107 particles) were characterized and encapsulated inside 100 μl hydrogel composed of alginate (3 % w/v; Alg)/gelatin (Gel; 1 % w/v) enriched with 1 μM pyrrole (Pyr) solidified in the presence of 0.2 M FeCl3. The physicochemical properties and cytocompatibility of prepared hydrogels were assessed using FTIR, swelling, biodegradation, porosity assays, and scanning electron microscopy (SEM). The mitochondria-bearing hydrogel was injected into the ischemic area of rat hearts. FTIR absorption bands represented that the addition of FeCl3 led to polypyrrole (PPy) formation, polysaccharide oxidation, and interaction between Alg and Gel. SEM images exhibited porous structure and the size of pores was reduced in Alg/Gel + PPy group compared to Alg + PPy hydrogel. Based on the data, both Alg + PPy and Alg/Gel + PPy hydrogels can preserve the integrity and morphology of loaded mitochondria. It was noted that Alg/Gel + PPy hydrogel possessed a higher swelling ratio, degradation, and porosity compared to Alg + PPy group. Data confirmed that Alg/Gel + PPy hydrogel containing 1 μM Pyr yielded the highest survival rate compared to groups with 2 and 4 μM Pyr (p < 0.05). Injection of mitochondria-loaded Alg/Gel + PPy hydrogel yielded significant restoration of left ventricle thickness compared to the infarction, mitochondria, and Alg/Gel + PPy hydrogel groups 14 days post-injection (p < 0.05). Histological analyses revealed a significant increase of vWF+ capillaries and α-SMA+ arterioles in the mitochondria-loaded Alg/Gel + PPy hydrogel group (p < 0.05). Immunofluorescence imaging revealed the ability of rat cardiomyocytes to uptake mitochondria alone or after being loaded into Alg/Gel + PPy hydrogel. These effects were evident in the Alg/Gel + PPy group. Taken together, electroconductive Alg-based hydrogels are suitable platforms for the transplantation of cells and organelles and the regeneration of ischemic heart changes.

Engineered bone marrow mesenchymal stem cell-derived exosomes loaded with miR302 through the cardiomyocyte specific peptide can reduce myocardial ischemia and reperfusion (I/R) injury

BACKGROUND

MicroRNA (miRNA)-based therapies have shown great potential in myocardial repair following myocardial infarction (MI). MicroRNA-302 (miR302) has been reported to exert a protective effect on MI. However, miRNAs are easily degraded and ineffective in penetrating cells, which limit their clinical applications. Exosomes, which are small bioactive molecules, have been considered as an ideal vehicle for miRNAs delivery due to their cell penetration, low immunogenicity and excellent stability potential. Herein, we explored cardiomyocyte-targeting exosomes as vehicles for delivery of miR302 into cardiomyocyte to potentially treat MI.

METHODS

To generate an efficient exosomal delivery system that can target cardiomyocytes, we engineered exosomes with cardiomyocyte specific peptide (CMP, WLSEAGPVVTVRALRGTGSW). Afterwards, the engineered exosomes were characterized and identified using transmission electron microscope (TEM) and Nanoparticle Tracking Analysis (NTA). Later on, the miR302 mimics were loaded into the engineered exosomes via electroporation technique. Subsequently, the effect of the engineered exosomes on myocardial ischemia and reperfusion (I/R) injury was evaluated in vitro and in vivo, including MTT, ELISA, real-time quantitative polymerase chain reaction (PCR), western blot, TUNNEL staining, echocardiogram and hematoxylin and eosin (HE) staining.

RESULTS

Results of in vitro experimentation showed that DSPE-PEG-CMP-EXO could be more efficiently internalized by H9C2 cells than unmodified exosomes (blank-exosomes). Importantly, compared with the DSPE-PEG-CMP-EXO group, DSPE-PEG-CMP-miR302-EXO significantly upregulated the expression of miR302, while exosomes loaded with miR302 could enhance proliferation of H9C2 cells. Western blot results showed that the DSPE-PEG-CMP-miR302-EXO significantly increased the protein level of Ki67 and Yap, which suggests that DSPE-PEG-CMP-miR302-EXO enhanced the activity of Yap, the principal downstream effector of Hippo pathway. In vivo, DSPE-PEG-CMP-miR302-EXO improved cardiac function, attenuated myocardial apoptosis and inflammatory response, as well as reduced infarct size significantly.

CONCLUSION

In conclusion, our findings suggest that CMP-engineered exosomes loaded with miR302 was internalized by H9C2 cells, an in vitro model for cardiomyocytes coupled with potential enhancement of the therapeutic effects on myocardial I/R injury.

FAM3A Deficiency - Induced Mitochondrial Dysfunction Underlies Post-Infarct Mortality and Heart Failure

Mitochondrial protein sequence similarity 3 gene family member A (FAM3A) plays important roles in the electron transfer chain, while its functions in the heart are still unknown. This study aims to explore the roles and mechanisms of FAM3A after myocardial infarction (MI). FAM3A-deficient (Fam3a-/-) mice were implemented with MI injury and showed lower survival rates at 4 weeks as well as decreased cardiac systolic function. Isolated cardiomyocytes of Fam3a-/- mice showed reduced basal, ATP-linked respiration and respiratory reserve compared to that of wild-type mice. Transmission electron microscopy studies showed Fam3a-/- mice had a larger size and elevated density of mitochondria. FAM3A deficiency also induced elevated mitochondrial Ca2+, higher opening level of mPTP, lower mitochondrial membrane potential and elevated apoptotic rates. Further analyses demonstrated that mitochondrial dynamics protein Opa1 contributed to the effects of FAM3A in cardiomyocytes. Our study discloses the important roles of mitochondrial protein FAM3A in the heart.

Rhein alleviates myocardial ischemic injury by inhibiting mitochondrial division, activating mitochondrial autophagy and suppressing myocardial cell apoptosis through the Drp1/Pink1/Parkin pathway

BACKGROUND

Rhein, which has antioxidant and anti-inflammatory response properties, is a beneficial treatment for different pathologies. However, the mechanism by which rhein protects against myocardial ischemic injury is poorly understood.

METHODS AND RESULTS

To establish an acute myocardial infarction (AMI) rat model, we performed left anterior descending (LAD) ligation. Sprague‒Dawley rats were randomly divided into four groups: sham, AMI, AMI + rhein (AMI + R), and AMI + mitochondrial fission inhibitor (AMI + M). The extent of myocardial injury was evaluated by TTC staining, serum myocardial injury markers, and HE and Masson staining. Cardiac mitochondria ultrastructure was visualized by transmission electron microscopy. TUNEL assay and flow cytometry analysis were used to estimate cell apoptosis. Protein expression levels were measured by Western blotting. In vitro, the efficacy of rhein was assessed in H9c2 cells under hypoxic condition. Our results revealed that rats with AMI exhibited increased infarct size and indicators of myocardial damage, along with activation of Drp1-dependent mitochondrial fission, decreased mitophagy and increased apoptosis rates. However, pretreatment with rhein significantly reversed these effects and demonstrated similar efficacy to Mdivi-1. Furthermore, rhein pretreatment protected against myocardial ischemic injury by inhibiting mitochondrial fission, as evidenced by decreased Drp1 expression. It also enhanced mitophagy, as indicated by increased expression of Beclin1, Pink1 and Parkin, an increased LC3-II/LC3-I ratio and increased formation of autolysosomes. Additionally, rhein pretreatment mitigated apoptosis in AMI. These results were also confirmed in vitro in H9c2 cells.

CONCLUSION

Our results demonstrate that rhein pretreatment exerts cardioprotective effects against myocardial ischemic injury via the Drp1/Pink1/Parkin pathway.

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.

Dual-specificity phosphatase 1 interacts with prohibitin 2 to improve mitochondrial quality control against type-3 cardiorenal syndrome

Type-3 cardiorenal syndrome (CRS-3) is acute kidney injury followed by cardiac injury/dysfunction. Mitochondrial injury may impair myocardial function during CRS-3. Since dual-specificity phosphatase 1 (DUSP1) and prohibitin 2 (PHB2) both promote cardiac mitochondrial quality control, we assessed whether these proteins were dysregulated during CRS-3-related cardiac depression. We found that DUSP1 was downregulated in heart tissues from a mouse model of CRS-3. DUSP1 transgenic (DUSP1Tg) mice were protected from CRS-3-induced myocardial damage, as evidenced by their improved heart function and myocardial structure. CRS-3 induced the inflammatory response, oxidative stress and mitochondrial dysfunction in wild-type hearts, but not in DUSP1Tg hearts. DUSP1 overexpression normalized cardiac mitochondrial quality control during CRS-3 by suppressing mitochondrial fission, restoring mitochondrial fusion, re-activating mitophagy and augmenting mitochondrial biogenesis. We found that DUSP1 sustained cardiac mitochondrial quality control by binding directly to PHB2 and maintaining PHB2 phosphorylation, while CRS-3 disrupted this physiological interaction. Transgenic knock-in mice carrying the Phb2S91D variant were less susceptible to cardiac depression upon CRS-3, due to a reduced inflammatory response, suppressed oxidative stress and improved mitochondrial quality control in their heart tissues. Thus, CRS-3-induced myocardial dysfunction can be attributed to reduced DUSP1 expression and disrupted DUSP1/PHB2 binding, leading to defective cardiac mitochondrial quality control.

Metabolic Flexibility of the Heart: The Role of Fatty Acid Metabolism in Health, Heart Failure, and Cardiometabolic Diseases

This comprehensive review explores the critical role of fatty acid (FA) metabolism in cardiac diseases, particularly heart failure (HF), and the implications for therapeutic strategies. The heart's reliance on ATP, primarily sourced from mitochondrial oxidative metabolism, underscores the significance of metabolic flexibility, with fatty acid oxidation (FAO) being a dominant source. In HF, metabolic shifts occur with an altered FA uptake and FAO, impacting mitochondrial function and contributing to disease progression. Conditions like obesity and diabetes also lead to metabolic disturbances, resulting in cardiomyopathy marked by an over-reliance on FAO, mitochondrial dysfunction, and lipotoxicity. Therapeutic approaches targeting FA metabolism in cardiac diseases have evolved, focusing on inhibiting or stimulating FAO to optimize cardiac energetics. Strategies include using CPT1A inhibitors, using PPARα agonists, and enhancing mitochondrial biogenesis and function. However, the effectiveness varies, reflecting the complexity of metabolic remodeling in HF. Hence, treatment strategies should be individualized, considering that cardiac energy metabolism is intricate and tightly regulated. The therapeutic aim is to optimize overall metabolic function, recognizing the pivotal role of FAs and the need for further research to develop effective therapies, with promising new approaches targeting mitochondrial oxidative metabolism and FAO that improve cardiac function.

Didymin protects pancreatic beta cells by enhancing mitochondrial function in high-fat diet-induced impaired glucose tolerance

PURPOSE

Prolonged exposure to plasma free fatty acids (FFAs) leads to impaired glucose tolerance (IGT) which can progress to type 2 diabetes (T2D) in the absence of timely and effective interventions. High-fat diet (HFD) leads to chronic inflammation and oxidative stress, impairing pancreatic beta cell (PBC) function. While Didymin, a flavonoid glycoside derived from citrus fruits, has beneficial effects on inflammation dysfunction, its specific role in HFD-induced IGT remains yet to be elucidated. Hence, this study aims to investigate the protective effects of Didymin on PBCs.

METHODS

HFD-induced IGT mice and INS-1 cells were used to explore the effect and mechanism of Didymin in alleviating IGT. Serum glucose and insulin levels were measured during the glucose tolerance and insulin tolerance tests to evaluate PBC function and insulin resistance. Next, RNA-seq analysis was performed to identify the pathways potentially influenced by Didymin in PBCs. Furthermore, we validated the effects of Didymin both in vitro and in vivo. Mitochondrial electron transport inhibitor (Rotenone) was used to further confirm that Didymin exerts its ameliorative effect by enhancing mitochondria function.

RESULTS

Didymin reduces postprandial glycemia and enhances 30-minute postprandial insulin levels in IGT mice. Moreover, Didymin was found to enhance mitochondria biogenesis and function, regulate insulin secretion, and alleviate inflammation and apoptosis. However, these effects were abrogated with the treatment of Rotenone, indicating that Didymin exerts its ameliorative effect by enhancing mitochondria function.

CONCLUSIONS

Didymin exhibits therapeutic potential in the treatment of HFD-induced IGT. This beneficial effect is attributed to the amelioration of PBC dysfunction through improved mitochondrial function.

Dynamin-related protein 1 is a critical regulator of mitochondrial calcium homeostasis during myocardial ischemia/reperfusion injury

Dynamin-related protein 1 (Drp1) is a cytosolic GTPase protein that when activated translocates to the mitochondria, meditating mitochondrial fission and increasing reactive oxygen species (ROS) in cardiomyocytes. Drp1 has shown promise as a therapeutic target for reducing cardiac ischemia/reperfusion (IR) injury; however, the lack of specificity of some small molecule Drp1 inhibitors and the reliance on the use of Drp1 haploinsufficient hearts from older mice have left the role of Drp1 in IR in question. Here, we address these concerns using two approaches, using: (a) short-term (3 weeks), conditional, cardiomyocyte-specific, Drp1 knockout (KO) and (b) a novel, highly specific Drp1 GTPase inhibitor, Drpitor1a. Short-term Drp1 KO mice exhibited preserved exercise capacity and cardiac contractility, and their isolated cardiac mitochondria demonstrated increased mitochondrial complex 1 activity, respiratory coupling, and calcium retention capacity compared to controls. When exposed to IR injury in a Langendorff perfusion system, Drp1 KO hearts had preserved contractility, decreased reactive oxygen species (ROS), enhanced mitochondrial calcium capacity, and increased resistance to mitochondrial permeability transition pore (MPTP) opening. Pharmacological inhibition of Drp1 with Drpitor1a following ischemia, but before reperfusion, was as protective as Drp1 KO for cardiac function and mitochondrial calcium homeostasis. In contrast to the benefits of short-term Drp1 inhibition, prolonged Drp1 ablation (6 weeks) resulted in cardiomyopathy. Drp1 KO hearts were also associated with decreased ryanodine receptor 2 (RyR2) protein expression and pharmacological inhibition of the RyR2 receptor decreased ROS in post-IR hearts suggesting that changes in RyR2 may have a role in Drp1 KO mediated cardioprotection. We conclude that Drp1-mediated increases in myocardial ROS production and impairment of mitochondrial calcium handling are key mechanisms of IR injury. Short-term inhibition of Drp1 is a promising strategy to limit early myocardial IR injury which is relevant for the therapy of acute myocardial infarction, cardiac arrest, and heart transplantation.

Tetrahydrocurcumin ameliorates postinfarction cardiac dysfunction and remodeling by inhibiting oxidative stress and preserving mitochondrial function via SIRT3 signaling pathway

BACKGROUND

Myocardial infarction (MI) often leads to sudden cardiac death. Persistent myocardial ischemia increases oxidative stress and impairs mitochondrial function, contributing significantly to postinfarction cardiac dysfunction and remodeling, and the subsequent progression to heart failure (HF). Tetrahydrocurcumin (THC), isolated from the rhizome of turmeric, has antioxidant properties and has been shown to protect against cardiovascular diseases. However, its effects on HF after MI are poorly understood.

PURPOSE

The objective was the investigation of the pharmacological effects of THC and its associated mechanisms in the pathogenesis of HF after MI.

METHODS

A total of 120 mice (C57BL/6, male) were used for the in vivo experiments. An MI mouse model was created by permanent ligation of the left anterior descending coronary artery. The mice received oral dose of THC at 120 mg/kg/d and the effects on MI-induced myocardial injury were evaluated by assessment of cardiac function, histopathology, myocardial oxidative levels, and mitochondrial function. Molecular mechanisms were investigated by intraperitoneal injection of 50 mg/kg of the SIRT3 selective inhibitor 3-TYP. Meanwhile, mouse neonatal cardiomyocytes were isolated and cultured in a hypoxic incubator to verify the effects of THC in vitro. Lastly, SIRT3 and Nrf2 were silenced using siRNAs to further explore the regulatory mechanism of key molecules in this process.

RESULTS

The mouse hearts showed significant impairment in systolic function after MI, together with enlarged infarct size, increased myocardial fibrosis, cardiac hypertrophy, and apoptosis of cardiomyocytes. A significant reversal of these changes was seen after treatment with THC. Moreover, THC markedly reduced reactive oxygen species generation and protected mitochondrial function, thus mitigating oxidative stress in the post-MI myocardium. Mechanistically, THC counteracted reduced Nrf2 nuclear accumulation and SIRT3 signaling in the MI mice while inhibition of Nrf2 or SIRT3 reversed the effects of THC. Cell experiments showed that Nrf2 silencing markedly reduced SIRT3 levels and deacetylation activity while inhibition of SIRT3 signaling had little impact on Nrf2 expression.

CONCLUSION

This is the first demonstration that THC protects against the effects of MI. THC reduced both oxidative stress and mitochondrial damage by regulating Nrf2-SIRT3 signaling. The results suggest the potential of THC in treating myocardial ischemic diseases.

Remote ischaemic conditioning for fatigue after stroke (RICFAST): A pilot randomised controlled trial

BACKGROUND

Post stroke fatigue (PSF) affects 50 % of stroke survivors, and can be disabling. Remote ischaemic conditioning (RIC), can preserve mitochondrial function, improve tissue perfusion and may mitigate PSF. This pilot randomised controlled trial evaluates the safety and feasibility of using RIC for PSF and evaluated measures of cellular bioenergetics.

METHODS

24 people with debilitating PSF (7 item Fatigue Severity Score, FSS-7 > 4) were randomised (1:1) in this single-centre phase 2 study to RIC (blood pressure cuff inflation around the upper arm 200 mmHg for 5 min followed by 5 min of deflation), or sham (inflation pressure 20 mmHg), repeated 4 cycles, 3 times per week for 6 weeks. Primary outcomes were safety, acceptability, and compliance. Secondary outcomes included FSS-7, 6 min walking test (6MWT), peak oxygen consumption (V̇O2peak), ventilatory anaerobic threshold (VAT), and muscle adenosine triphosphate (ATP) content measured using 31-phosphorous magnetic resonance spectroscopy of tibialis anterior.

RESULTS

RIC was safe (no serious adverse events, adverse events mild) and adherence excellent (91 % sessions completed). Exploratory analysis revealed lower FSS-7 scores in the RIC group compared to sham at 6 weeks (between group difference FSS-7 -0.7, 95 %CI -2.0 to 0.6), 3 months (-1.0, 95 %CI -2.2 to 0.2) and 6 months (-0.9, 95 %CI -2.0 to 0.2). There were trends towards increased VAT, increased muscle ATP content and improved 6MWT in the RIC group.

DISCUSSION

RIC is safe and acceptable for people with PSF and may result in clinically meaningful improvements in fatigue and muscle bioenergetics that require further investigation in larger studies.

The interplay between H19 and HIF-1α in mitochondrial dysfunction in myocardial infarction

Myocardial infarction(MI) causes prolonged ischemia of infarcted myocardial tissue, which triggers a wide range of hypoxia cellular responses in cardiomyocytes. Emerging evidence has indicated the critical roles of long non-coding RNAs(lncRNAs) in cardiovascular diseases, including MI. The purpose of this study was to investigate the roles of lncRNA H19 and H19/HIF-1α pathway during MI. Results showed that cell injury and mitochondrial dysfunction were induced in hypoxia-treated H9c2 cells, accompanied by an increase in the expression of H19. H19 silencing remarkably diminishes cell injury, inhibits the dysfunctional degree of mitochondria, and decreases the injury of MI rats. Bioinformatics analysis and dual-luciferase assays revealed that H19 was the hypoxia-responsive lncRNA, and HIF-1α induced H19 transcription through direct binding to the H19 promoter. Moreover, H19 participates in the HIF-1α pathway by stabilizing the HIF-1α protein. These results indicated that H19 might be a potential biomarker and therapeutic target for myocardial infarction.