Proteinase‑activated receptor 2 deficiency is a protective factor against cardiomyocyte apoptosis during myocardial ischemia/reperfusion injury

Xa inhibitor edoxaban ameliorates hepatic ischemia-reperfusion injury via PAR-2-ERK 1/2 pathway

Hepatic ischemia-reperfusion injury causes liver damage during surgery. In hepatic ischemia-reperfusion injury, the blood coagulation cascade is activated, causing microcirculatory incompetence and cellular injury. Coagulation factor Xa (FXa)- protease-activated receptor (PAR)-2 signaling activates inflammatory reactions and the cytoprotective effect of FXa inhibitor in several organs. However, no studies have elucidated the significance of FXa inhibition on hepatic ischemia-reperfusion injury. The present study elucidated the treatment effect of an FXa inhibitor, edoxaban, on hepatic ischemia-reperfusion injury, focusing on FXa-PAR-2 signaling. A 60 min hepatic partial-warm ischemia-reperfusion injury mouse model and a hypoxia-reoxygenation model of hepatic sinusoidal endothelial cells were used. Ischemia-reperfusion injury mice and hepatic sinusoidal endothelial cells were treated and pretreated, respectively with or without edoxaban. They were incubated during hypoxia/reoxygenation in vitro. Cell signaling was evaluated using the PAR-2 knockdown model. In ischemia-reperfusion injury mice, edoxaban treatment significantly attenuated fibrin deposition in the sinusoids and liver histological damage and resulted in both anti-inflammatory and antiapoptotic effects. Hepatic ischemia-reperfusion injury upregulated PAR-2 generation and enhanced extracellular signal-regulated kinase 1/2 (ERK 1/2) activation; however, edoxaban treatment reduced PAR-2 generation and suppressed ERK 1/2 activation in vivo. In the hypoxia/reoxygenation model of sinusoidal endothelial cells, hypoxia/reoxygenation stress increased FXa generation and induced cytotoxic effects. Edoxaban protected sinusoidal endothelial cells from hypoxia/reoxygenation stress and reduced ERK 1/2 activation. PAR-2 knockdown in the sinusoidal endothelial cells ameliorated hypoxia/reoxygenation stress-induced cytotoxicity and suppressed ERK 1/2 phosphorylation. Thus, edoxaban ameliorated hepatic ischemia-reperfusion injury in mice by protecting against micro-thrombosis in sinusoids and suppressing FXa-PAR-2-induced inflammation in the sinusoidal endothelial cells.

YQHX Alleviates H/R-Induced Cardiomyocyte Apoptosis by Downregulating miR-1

Yiqi Huoxue granule (YQHX) inhibits cardiomyocyte apoptosis in myocardial ischemia-reperfusion injury (MIRI); however, the underlying mechanism is unknown. In this study, hypoxia-reoxygenation (H/R) models were established using rat myocardial primary cells and H9c2 cells, lactate dehydrogenase (LDH), and creatine kinase (CK) levels and cardiomyocyte apoptosis were determined. LDH release, CK activity, caspase-3 activation, mRNA and protein ratio of Bax/Bcl-2, and miR-1 expression were significantly higher (p < 0.01) in the H/R model of rat myocardial primary cells and H9c2 cells compared with the control group and was inhibited by YQHX treatment (p < 0.01 or p < 0.05). We also found that miR-1 overexpression could enhance apoptosis in cardiomyocytes, whereas apoptosis could be reduced by YQHX treatment (p < 0.01). In conclusion, YQHX alleviates H/R-induced cardiomyocyte apoptosis by inhibiting miR-1 expression, suggesting the potential of YQHX in preventing MIRI.

CD146+Mesenchymal stem cells treatment improves vascularization, muscle contraction and VEGF expression, and reduces apoptosis in rat ischemic hind limb

Peripheral arterial disease (PAD) is an increasingly common narrowing of the peripheral arteries that can lead to lower limb ischemia, muscle weakness and gangrene. Surgical vein or arterial grafts could improve PAD, but may not be suitable in elderly patients, prompting research into less invasive approaches. Mesenchymal stem cells (MSCs) have been proposed as potential therapy, but their effectiveness and underlying mechanisms in limb ischemia are unclear. We tested the hypothesis that treatment with naive MSCs (nMSCs) or MSCs expressing CD146 (^CD146+MSCs) could improve vascularity and muscle function in rat model of hind-limb ischemia. Sixteen month old Sprague-Dawley rats were randomly assigned to 4 groups: sham-operated control, ischemia, ischemia + nMSCs and ischemia+^CD146+MSCs. After 4 weeks of respective treatment, rat groups were assessed for ischemic clinical score, Tarlov score, muscle capillary density, TUNEL apoptosis assay, contractile force, and vascular endothelial growth factor (VEGF) mRNA expression. ^CD146+MSCs showed greater CD146 mRNA expression than nMSCs. Treatment with nMSCs or ^CD146+MSCs improved clinical and Tarlov scores, muscle capillary density, contractile force and VEGF mRNA expression in ischemic limbs as compared to non-treated ischemia group. The improvements in muscle vascularity and function were particularly greater in ischemia+^CD146+MSCs than ischemia + nMSCs group. TUNEL positive apoptotic cells were least abundant in ischemia+^CD146+MSCs compared with ischemia + nMSCs and non-treated ischemia groups. Thus, MSCs particularly those expressing CD146 improve vascularity, muscle function and VEGF expression and reduce apoptosis in rat ischemic limb, and could represent a promising approach to improve angiogenesis and muscle function in PAD.