Increasing angiotensin-converting enzyme(ACE)2/ACE axes ratio alleviates early pulmonary vascular remodeling in a porcine model of acute pulmonary embolism with cardiac arrest

BACKGROUND:Acute pulmonary embolism(APE)with cardiac arrest(CA)is characterized by high mortality in emergency due to pulmonary arterial hypertension(PAH).This study aims to determine whether early pulmonary artery remodeling occurs in PAH caused by massive APE with CA and the protective effects of increasing angiotensin-converting enzyme(ACE)2-angiotensin(Ang)(1-7)-Mas receptor axis and ACE-Ang II-Ang II type 1 receptor(AT1)axis(ACE2/ACE axes)ratio on pulmonary artery lesion after return of spontaneous circulation(ROSC).METHODS:To establish a porcine massive APE with CA model,autologous thrombus was injected into the external jugular vein until mean arterial pressure dropped below 30 mmHg(1 mmHg=0.133 kPa).Cardiopulmonary resuscitation and thrombolysis were delivered to regain spontaneous circulation.Pigs were divided into four groups of five pigs each:control group,APE-CA group,ROSC-saline group,and ROSC-captopril group,to examine the endothelial pathological changes and expression of ACE2/ACE axes in pulmonary artery with or without captopril.RESULTS:Histological analysis of samples from the APE-CA and ROSC-saline groups showed that pulmonary arterioles were almost completely occluded by accumulated endothelial cells.Western blotting analysis revealed a decrease in the pulmonary arterial ACE2/ACE axes ratio and increases in angiopoietin-2/angiopoietin-1 ratio and expression of vascular endothelial growth factor(VEGF)in the APE-CA group compared with the control group.Captopril significantly suppressed the activation of angiopoietin-2/angiopoietin-1 and VEGF in plexiform lesions formed by proliferative endothelial cells after ROSC.Captopril also alleviated endothelial cell apoptosis by increasing the B-cell lymphoma-2(Bcl-2)/Bcl-2-associated X(Bax)ratio and decreasing cleaved caspase-3 expression.CONCLUSION:Increasing the ACE2/ACE axes ratio may ameliorate pulmonary arterial remodeling by inhibiting the apoptosis and proliferation of endothelial cells after ROSC induced by APE.

Green Tea Polyphenols Prevent Early Vascular Aging Induced by High-Fat Diet via Promoting Autophagy in Young Adult Rats

Objective Epidemiology studies indicate that green tea polyphenols(GTP)perform a protective effect on cardiovascular diseases,but the underlying mechanisms are complex.The present study aimed to investigate the effect of GTP on high-fat diets(HFD)induced-early vascular aging.Methods Six-week young adult Wistar rats were fed with standard chow or HFD in the presence and absence of GTP(200 mg/kg body weight)for 18 weeks.In vitro experiment,human umbilical vascular endothelial cells(HUVECs)were treated with palmitic acid(PA)and GTP.Results The results showed that GTP alleviated the disorganized arterial wall and the increased intima-media thickness induced by HFD.In addition,the vascular oxidative injury was suppressed following GTP treatment.Furthermore,GTP elevated the ratio of LC3-II/LC3-I and suppressed expression of p62/SQSTM1,and restored SIRT3 expression in the aorta of HFD rats.Consistently,in cultured HUVECs,GTP inhibited cell senescence indicated by SA-β-gal and promoted endothelial autophagy compared with the PA treatment group.The activity of SIRT3 was specifically inhibited by 3-TYP,and the protective effect of GTP was consequently abolished.Conclusion The findings indicated that GTP protected against early vascular senescence in young HFD rats via ameliorating oxidative injury and promoting autophagy which was partially regulated by the SIRT3 pathway.