The Effect of Remote Ischemic Preconditioning (RIPC) on Blood Pressure and Its Vascular Protection Effect

Hypertension is one of the most common world-wide chronic diseases, and it is one of major independent risk factors of atherosclerotic cardiovascular diseases (ASCVD) especially among middle-aged and elderly. Recently, a study indicates that in a normotensive elderly without cardiovascular diseases history, continuous RIPC for 30 days lowers systolic blood pressure for 6 mmHg and diastolic blood pressure for 3 mmHg. Another study shows a 7-day RIPC intervention improves endothelium-dependent flow mediated dilation(FDM) and cutaneous vascular conductivity(CVC) in 13 healthy young males. In addition, studies demonstrate that microRNA-126 and microRNA-34a are endothelial specific microRNAs which are expressed in human PBMCs. MicroRNA-126 is responsible for keeping the integrity of vascular endothelial, promoting the proliferation, mobilization, and migration of endothelial progenitor cells(EPCs), reducing arterial intimal hyperplasia, and reduce adhesion of neutrophils to vascular endothelial. In contrast, microRNA-34a is related to the aging of endothelial cells, which is found over-expressed in senile endothelial cells. Together the investigators use microRNA-126 and microRNA-34a to explore whether RIPC produces vascular endothelial protection effect. In summary, the investigators propose a hypothesis that RIPC might have a blood pressure lowing effect and protect vascular function both in Chinese healthy young adults and primary hypertensive patients. The term "primary hypertension stage I" indicates those with blood pressures ranging from 140 to 159 mmHg systolic and/or 90 to 99 mmHg diastolic. Accumulating evidences suggest that subjects with primary hypertension stage I are associated with higher incidence of ASCVD. However, there is no available data to investigate a nonpharmacologic therapy for primary hypertension stage I until now, and there is no prospective, randomized, controlled, single-blind clinic trial to investigate the effect of RIPC on blood pressure and its vascular protection effect. The investigators hypothesize that RIPC may lower both SBP and DBP, and it improves vascular function in Chinese healthy young adults and subjects with primary hypertension stage I. To address these assumptions, the present study is designed to study the effect of RIPC on blood pressure and its vascular protection effect, using FMD, PWV, central arterial pressure, RHI(EndoPAT) and the quantification of microRNA-126 and microRNA-34a in peripheral blood monocyte(PBMC) as indicators among Chinese healthy young adults and primary hypertensive patients stage I over a 1-month follow-up period.