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Ischemia/reperfusion (I/R) injury following myocardial infarction is a major cause of cardiomyocyte death and impaired cardiac function. Although clinical data show that metformin is effective in repairing cardiac I/R injury, its efficacy is hindered by non-specific targeting during administration, a short half-life, frequent dosing, and potential adverse effects on the liver and kidneys. In recent years, injectable hydrogels have shown substantial potential in overcoming drug delivery challenges and treating myocardial infarction. To this end, we developed a natural polymer hydrogel system comprising methacryloylated chitosan and methacryloylated gelatin modified with polyaniline conductive derivatives. In vitro studies demonstrated that the optimized hydrogel exhibited excellent injectability, biocompatibility, biodegradability, suitable mechanical properties, and electrical conductivity. Incorporating metformin into this hydrogel significantly extended the administration cycle, mitigated mitochondrial damage, decreased abnormal ROS production, and enhanced cardiomyocyte function. Animal experiments indicated that the metformin/hydrogel system reduced arrhythmia incidence, infarct size, and improved cardiac mitochondrial and overall cardiac function, promoting myocardial repair in I/R injury. Overall, the metformin-loaded conductive hydrogel system effectively mitigates mitochondrial oxidative damage and improves cardiomyocyte function, thereby offering a theoretical foundation for the potential application of metformin in cardioprotection.

OBJECTIVE: Na+-activated Slack potassium (K+) channels are increasingly recognized as regulators of neuronal activity, yet little is known about their role in the cardiovascular system. Slack activity increases when intracellular Na+ concentration ([Na+]i) reaches pathophysiological levels. Elevated [Na+]i is a major determinant of the ischemia and reperfusion (I/R)-induced myocardial injury, thus we hypothesized that Slack plays a role under these conditions.
METHODS: and results: K+ currents in cardiomyocytes (CMs) obtained from wildtype (WT) but not from global Slack knockout (KO) mice were sensitive to electrical inactivation of voltage-sensitive Na+-channels. Live-cell imaging demonstrated that K+ fluxes across the sarcolemma rely on Slack, while the depolarized resting membrane potential in Slack-deficient CMs led to excessive cytosolic Ca2+ accumulation and finally to hypoxia/reoxygenation-induced cell death. Cardiac damage in an in vivo model of I/R was exacerbated in global and CM-specific conditional Slack mutants and largely insensitive to mechanical conditioning maneuvers. Finally, the protection conferred by mitochondrial ATP-dependent K+ channels required functional Slack in CMs.
CONCLUSIONS: Collectively, our study provides evidence for Slack\'s crucial involvement in the ion homeostasis of no or low O2-stressed CMs. Thereby, Slack activity opposes the I/R-induced fatal Ca2+-uptake to CMs supporting the cardioprotective signaling widely attributed to mitoKATP function.

The rhizome of Corydalis decumbens is a traditional Chinese medicine commonly utilized in the clinical treatment of acute ischemic stroke. Numerous phytochemical and biological investigations have demonstrated that protoberberine alkaloids from C. decumbens exhibit diverse pharmaceutical activities against various diseases. Sinometumine E (SE), a protoberberine alkaloid isolated from C. decumbens for the first time, is characterized by a complex 6/6/6/6/6/6 hexacyclic skeleton. In the current study, we investigated the protective effects of SE on endothelial cell injury and its angiogenesis effects in zebrafish. The results suggested that SE showed significant anti-ischemic effects on OGD/R-induced HBEC-5i and HUVECs cell ischemia/reperfusion injury model. Furthermore, it promoted angiogenesis in PTK787-induced, MPTP-induced, and atorvastatin-induced vessel injury models of zebrafish, while also suppressing hypoxia-induced locomotor impairment in zebrafish. Transcriptome sequencing analysis provided a sign that SE likely to promotes angiogenesis through the HIF-1/VEGF signaling pathway to exert anti-ischemic effects. Consistently, SE modulated several genes related to HIF-1/VEGF signal pathway, such as hif-1, vegf, vegfr-2, pi3k, erk, akt and plcγ. Molecular docking analysis revealed that VEGFR-2 exhibited high binding affinity with SE, and western blot analysis confirmed that SE treatment enhanced the expression of VEGFR-2. In conclusion, our study profiled the angiogenic activities of SE in vitro and in vivo. The key targets and related pathways involved in anti-ischemic effects of SE, shedding light on the pharmacodynamic components and mechanisms of Corydalis decumbens, and provides valuable insights for identifying effective substances for the treatment of ischemic stroke.

Ischemia/reperfusion injury (IRI) represents a significant contributor to morbidity and mortality associated with various clinical conditions, including acute coronary syndrome, stroke, and organ transplantation. During ischemia, a profound hypoxic insult develops, resulting in cellular dysfunction and tissue damage. Paradoxically, reperfusion can exacerbate this injury through the generation of reactive oxygen species and the induction of inflammatory cascades. The extensive clinical sequelae of IRI necessitate the development of therapeutic strategies to mitigate its deleterious effects. This has become a cornerstone of ongoing research efforts in both basic and translational science. This review examines the use of molecular hydrogen for IRI in different organs and explores the underlying mechanisms of its action. Molecular hydrogen is a selective antioxidant with anti-inflammatory, cytoprotective, and signal-modulatory properties. It has been shown to be effective at mitigating IRI in different models, including heart failure, cerebral stroke, transplantation, and surgical interventions. Hydrogen reduces IRI via different mechanisms, like the suppression of oxidative stress and inflammation, the enhancement of ATP production, decreasing calcium overload, regulating cell death, etc. Further research is still needed to integrate the use of molecular hydrogen into clinical practice.

Acute limb ischemia (ALI) is defined as a sudden reduction in blood flow to a limb, resulting in cessation of blood flow and, therefore, cessation of the delivery of nutrients and oxygen to the tissues of the lower limb. Despite optimal treatment to restore blood flow to ischemic tissues, some patients may suffer from ischemia/reperfusion (I/R) syndrome, the most severe complication after a revascularization procedure used to restore blood flow. There are multiple molecular and cellular factors that are involved in each phase of ALI. This review focuses firstly on molecular and cellular factors of arterial thrombosis, highlighting the role of atherosclerotic plaques, smooth muscle cells (SMCs), and cytokine which may alter key components of the extracellular matrix (ECM). Then, molecular and cellular factors of arterial embolism will be discussed, highlighting the importance of thrombi composition. Molecular and cellular factors of ischemia/reperfusion syndrome are analyzed in depth, highlighting several important mechanisms related to tissue damage, such as inflammation, apoptosis, autophagy, necrosis, and necroptosis. Furthermore, local and general complications of ALI are discussed in the context of molecular alterations. Ultimately, the role of novel biomarkers and targeted therapies is discussed.

Acute kidney injury (AKI) is closely related to lysosomal dysfunction and ferroptosis in renal tubular epithelial cells (TECs), for which effective treatments are urgently needed. Although selenium nanoparticles (SeNPs) have emerged as promising candidates for AKI therapy, their underlying mechanisms have not been fully elucidated. Here, we investigated the effect of SeNPs on hypoxia/reoxygenation (H/R)-induced ferroptosis and lysosomal dysfunction in TECs in vitro and evaluated their efficacy in a murine model of ischemia/reperfusion (I/R)-AKI. We observed that H/R-induced ferroptosis was accompanied by lysosomal Fe2+ accumulation and dysfunction in TECs, which was ameliorated by SeNPs administration. Furthermore, SeNPs protected C57BL/6 mice against I/R-induced inflammation and ferroptosis. Mechanistically, we found that lysosomal Fe2+ accumulation and ferroptosis were associated with the excessive activation of NCOA4-mediated ferritinophagy, a process mitigated by SeNPs through the upregulation of X-box binding protein 1 (XBP1). Downregulation of XBP1 promoted ferritinophagy and partially counteracted the protective effects of SeNPs on ferroptosis inhibition in TECs. Overall, our findings revealed a novel role for SeNPs in modulating ferritinophagy, thereby improving lysosomal function and attenuating ferroptosis of TECs in I/R-AKI. These results provide evidence for the potential application of SeNPs as therapeutic agents for the prevention and treatment of AKI.

Reperfusion after myocardial infarction (MI) can lead to myocardial ischemia/reperfusion (I/R) damage. The transcription factor (TF) broad-complex, tramtrack, and bric-a-brac (BTB) and cap\'n\'collar (CNC) homology 1 (BACH1) is implicated in the injury. However, the downstream mechanisms of BACH1 in affecting myocardial hypoxia/reoxygenation (H/R) damage are still fully understood. AC16 cells were stimulated with H/R conditions to model cardiomyocytes under H/R. mRNA analysis was performed by quantitative real-time PCR. Protein levels were gauged by immunoblot analysis. The effect of BACH1/cyclin-dependent kinase inhibitor 3 (CDKN3) on H/R-evoked injury was assessed by measuring cell viability via Cell Counting Kit-8 (CCK-8), apoptosis (flow cytometry and caspase 3 activity), ferroptosis via Fe2+, glutathione (GSH), reactive oxygen species (ROS) and malondialdehyde (MDA) markers and inflammation cytokines interleukin-1beta (IL-1β) and tumor necrosis factor alpha (TNF-α). The BACH1/CDKN3 relationship was examined by chromatin immunoprecipitation (ChIP) experiment and luciferase assay. BACH1 was increased in MI serum and H/R-stimulated AC16 cardiomyocytes. Functionally, disruption of BACH1 mitigated H/R-evoked in vitro apoptosis, ferroptosis and inflammation of AC16 cardiomyocytes. Mechanistically, BACH1 activated CDKN3 transcription and enhanced CDKN3 protein expression in AC16 cardiomyocytes. Our rescue experiments validated that BACH1 disruption attenuated H/R-evoked AC16 cardiomyocyte apoptosis, ferroptosis and inflammation by downregulating CDKN3. Additionally, BACH1 disruption could activate the adenosine monophosphate-activated protein kinase (AMPK) signaling by downregulating CDKN3 in H/R-stimulated AC16 cardiomyocytes. Our study demonstrates that BACH1 activates CDKN3 transcription to induce H/R-evoked damage of AC16 cardiomyocytes partially via AMPK signaling.

UNASSIGNED: To determine the efficacy of mechanical thrombectomy combined with prolonged mild hypothermia compared with conventional treatment in managing acute middle cerebral artery occlusion, and to explore whether extending the duration of hypothermia can improve neurological function.
UNASSIGNED: From 2018 to June 2023, a retrospective analysis was conducted on 45 patients with acute middle cerebral artery occlusion treated at the NICU of Suzhou Kowloon Hospital, affiliated with Shanghai Jiao Tong University School of Medicine. After thrombectomy, patients were admitted to the neurological intensive care unit (NICU) for targeted temperature management. Patients were divided into two groups: the mild hypothermia group (34.5-35.9°C) receiving 5-7 days of treatment, and the normothermia group (control group) whose body temperature was kept between 36 and 37.5°C using pharmacological and physical cooling methods. Baseline characteristics and temperature changes were compared between the two groups of patients. The primary outcome was the modified Rankin Scale (mRS) score at 3 month after surgery, and the secondary outcomes were related complications and mortality rate. Prognostic risk factors were investigated using both univariate and multivariate logistic regression analyses.
UNASSIGNED: Among 45 patients, 21 underwent prolonged mild hypothermia, and 24 received normothermia, with no significant differences in baseline characteristics between the two groups. The duration of mild hypothermia ranged from 5 to 7 days. The incidence of chills (33.3% vs. 8.3%, p = 0.031) and constipation (57.1% vs. 20.8%, p = 0.028) was significantly higher in the mild hypothermia group compared with the control group. There was no significant difference in mortality rates between the mild hypothermia and the control group (4.76% vs. 8.33%, p = 1.000, OR = 1.75, 95% CI, 0.171-17.949). At 3 month, there was no significant difference in the modified mRS (0-3) score between the mild hypothermia and control groups (52.4% vs. 25%, p = 0.114, OR = 0.477, 95% CI, 0.214-1.066). Infarct core volume was an independent risk factor for adverse neurological outcomes.
UNASSIGNED: Prolonged mild hypothermia following mechanical thrombectomy had no severe complications and shows a trend to improve the prognosis of neurological function. The Infarct core volume on CTP was an independent risk factor for predicting neurological function.

OBJECTIVE: The histone deacetylase 6 (HDAC6) inhibitor, tubastatin A, reduces myocardial ischemia/reperfusion injury (MIRI) in type 1 diabetic rats. It remains unclear whether HDAC6 regulates MIRI in type 2 diabetic animals. Diabetes augments activity of HDAC6 and generation of tumor necrosis factor α (TNFα) and impairs mitochondrial complex I (mCI). Here we examined how HDAC6 regulates TNFα production, mCI activity, mitochondria, and cardiac function in type 1 and type 2 diabetic mice undergoing MIRI.
RESULTS: HDAC6 knockout, streptozotocin-induced type 1 diabetic, and obese type 2 diabetic db/db mice underwent MIRI in vivo or ex vivo in a Langendorff-perfused system. We found that MIRI and diabetes additively augmented myocardial HDAC6 activity and generation of TNFα, along with cardiac mitochondrial fission, low bioactivity of mCI, and low production of ATP. Importantly, genetic disruption of HDAC6 or tubastatin A decreased TNFα levels, mitochondrial fission, and myocardial mitochondrial NADH levels in ischemic/reperfused diabetic mice, concomitant with augmented mCI activity, decreased infarct size, and improved cardiac function. Moreover, HDAC6 knockout or tubastatin A treatment decreased left ventricular dilation and improved cardiac systolic function 28 days after MIRI. H9c2 cardiomyocytes with and without HDAC6 knockdown were subjected to hypoxia/reoxygenation injury in the presence of high glucose. Hypoxia/reoxygenation augmented HDAC6 activity and TNFα levels and decreased mCI activity. These negative effects were blocked by HDAC6 knockdown.
CONCLUSIONS: HDAC6 is an essential negative regulator of MIRI in diabetes. Genetic deletion or pharmacologic inhibition of HDAC6 protects the heart from MIRI by limiting TNFα-induced mitochondrial injury in experimental diabetes.