Sevoflurane postconditioning attenuates cardiomyocytes hypoxia/reoxygenation injury via PI3K/AKT pathway mediated HIF-1α to regulate the mitochondrial dynamic balance.

BACKGROUND: Myocardial ischemia-reperfusion injury (I/RI) is a major cause of perioperative cardiac-related adverse events and death. Studies have shown that sevoflurane postconditioning (SpostC), which attenuates I/R injury and exerts cardioprotective effects, regulates mitochondrial dynamic balance via HIF-1α, but the exact mechanism is unknown. This study investigates whether the PI3K/AKT pathway in SpostC regulates mitochondrial dynamic balance by mediating HIF-1α, thereby exerting myocardial protective effects. METHODS: The H9C2 cardiomyocytes were cultured to establish the hypoxia-reoxygenation (H/R) model and randomly divided into 4 groups: Control group, H/R group, sevoflurane postconditioning (H/R + SpostC) group and PI3K/AKT blocker (H/R + SpostC + LY) group. Cell survival rate was determined by CCK-8; Apoptosis rate was determined by flow cytometry; mitochondrial membrane potential was evaluated by Mito Tracker™ Red; mRNA expression levels of AKT, HIF-1α, Opa1and Drp1 were detected by quantitative real-time polymerase chain reaction (qRT-PCR); Western Blot assay was used to detect the protein expression levels of AKT, phosphorylated AKT (p-AKT), HIF-1α, Opa1 and Drp1. RESULTS: Compared with the H/R group, the survival rate of cardiomyocytes in the H/R + SpostC group increased, the apoptosis rate decreased and the mitochondrial membrane potential increased. qRT-PCR showed that the mRNA expression of HIF-1α and Opa1 were higher in the H/R + SpostC group compared with the H/R group, whereas the transcription level of Drp1 was lower in the H/R + SpostC group. In the H/R + SpostC + LY group, the mRNA expression of HIF-1α was lower than the H/R + SpostC group. There was no difference in the expression of Opa1 mRNA between the H/R group and the H/R + SpostC + LY group. WB assay results showed that compared with the H/R group, the protein expression levels of HIF-1α, Opa1, P-AKT were increased and Drp1 protein expression levels were decreased in the H/R + SpostC group. HIF-1α, P-AKT protein expression levels were decreased in the H/R + SpostC + LY group compared to the H/R + SpostC group. CONCLUSION: SpostC mediates HIF-1α-regulated mitochondrial fission and fusion-related protein expression to maintain mitochondrial dynamic balance by activating the PI3K/AKT pathway and increasing AKT phosphorylation, thereby attenuating myocardial I/R injury.

miR-3064-5p and miR-4745-5p affect heparin sensitivity in patients undergoing cardiac surgery by regulating AT-III and factor X mRNA levels.

Subject: Perioperative regulation of coagulation function through heparin in patients undergoing cardiac surgery with cardiopulmonary bypass is an important part of performing cardiac surgery, and postoperative bleeding due to abnormal coagulation function caused by differences in heparin sensitivity in different individuals is an independent risk factor for postoperative complications and death. Method: Using an online database, 10 miRNAs interacting with AT-III and FX genes were predicted. Patients were divided into three groups according to the difference in activated clotting time (ACT) after the first dose of heparin (2.5 mg kg-1): group A: hyposensitive group (ACT < 480 s); group B: sensitive group (480 s ≤ ACT ≤ 760 s); and group C: hypersensitive group (ACT > 760 s). Perioperative and 24 h postoperative blood loss and other clinical data of patients in the three groups were recorded. Blood samples were collected before surgery, and RT-PCR was used to detect the levels of AT-III and FX gene mRNA and the levels of predicted 10 miRNAs. Result: Heparin sensitivity was positively correlated with AT-III mRNA levels and negatively correlated with FX gene mRNA levels in the three groups, and the blood loss in group B was significantly lower than that in groups A and C, which was statistically significant (p < 0.05). miR-3064-5p and miR-4745-5p expression levels were significantly different among group A, group B, and group C (p < 0.05) and were closely correlated with AT-III and FX gene mRNA expression levels, respectively. Conclusion: Differences in heparin sensitivity in patients undergoing cardiac surgery were associated with the mRNA expression of AT-III and FX genes, and the expression levels of miR-3064-5p and miR-4745-5p were found to be closely related to the AT-III and FX gene mRNA, respectively, indicating that miR-3064-5p and miR-4745-5p affect the differences in heparin sensitivity among different individuals by regulating the mRNA expression levels of AT-III and FX genes. Clinical Trial Registration: http://www.chictr.org.cn/abouten.aspx, identifier registration number: ChiCTR-2100047348.

Role of HIF-1α/BNIP3 signaling pathway in dexmedetomidine-induced reduction of myocardial ischemia-reperfusion-induced brain injury in mice / 中华麻醉学杂志

Objective:To evaluate the role of hypoxia-inducible factor-1α (HIF-1α)/Bcl-2/E1B 19-kDa interacting protein 3 (BNIP3) signaling pathway in dexmedetomidine-induced reduction of myocardial ischemia-reperfusion (I/R)-induced brain injury in mice.Methods:Sixty clean-grade healthy male C57BL/6 mice, aged 8-10 weeks, weighting 20-30 g, were divided into 5 groups ( n=12 each) using a random number table method: sham operation group (S group), myocardial I/R group (IR group), myocardial I/R plus dexmedetomidine group (IRD group), myocardial I/R plus HIF-1α inhibitor 2ME2 group (IR-M group), and myocardial I/R plus dexmedetomidine plus HIF-1α inhibitor 2ME2 group (IRD-M group). The myocardial I/R-induced brain injury was produced by ligating the left anterior descending coronary artery for 30 min followed by 2 h of reperfusion in anesthetized mice.Dexmedetomidine 50 μg/kg was intraperitoneally injected at 5 min before ischemia in IRD group and IRD-M group.In IR-M and IRD-M groups, 2ME2 15 mg/kg was intraperitoneally injected at 5 min before ischemia.Blood samples were collected from the thoracic aorta at 2 h of reperfusion to measure the serum S-100β protein and neuron-specific enolase (NSE) concentrations.The animals were then sacrificed, brains were removed and hippocampi were obtained for determination of the apoptosis index (by TUNEL method) and expression of HIF-1α, BNIP3, Beclin-1, microtubule-associated protein 1 light chain 3 (LC3) and phosphorylated Tau protein (p-Tau) (by Western blot) and for microscopic examination of the pathological changes in hippocampal CA1 region.LC3Ⅱ/Ⅰ ratio was calculated. Results:Compared with group S, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly increased, the expression of HIF-1α, BNIP3, Beclin-1 and p-Tau was up-regulated, LC3Ⅱ/Ⅰ ratio was increased ( P<0.05), and the pathological changes in hippocampal CA1 region were aggravated in group IR.Compared with group IR, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly decreased, the expression of HIF-1α, BNIP3 and Beclin-1 was up-regulated, the expression of p-Tau was down-regulated, and LC3Ⅱ/Ⅰ ratio was increased ( P<0.05), and the pathological changes in hippocampal CA1 region were significantly attenuated in group IRD.Compared with group IRD, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly increased, the expression of p-Tau was up-regulated, the expression of HIF-1α, BNIP3 and Beclin-1 was down-regulated, LC3Ⅱ/Ⅰ ratio was decreased ( P<0.05), and the pathological changes in hippocampal CA1 region were aggravated in IR-M and IRD-M groups. Conclusions:HIF-1α/BNIP3 signaling pathway is involved in dexmedetomidine-induced reduction of myocardial I/R-induced brain injury in mice.