Abstract： Objective To observe the expression changes of microRNA 1 （miRNA-1） and microRNA 21（miRNA-21） after ischemic preconditioning （IPC）, ischemic postconditioning （IPO） and remote ischemic preconditioning （RIPC）in an ischemia-reperfusion rat heart model in vitro, as well as the expression of their target protein heat shock protein 70 （HSP70） and programmed cell death 4 （PDCD4）, and evaluate whether miRNA are involved in endogenous cardio-protective mechanism. Methods The Langendorff-perfused Sprague-Dawley rat hearts were randomly assigned into one of the four groups, control group （CON group, n=12）, ischemia preconditioning group （IPC group， n=12） , ischemia postconditioning group （IPO group， n=12） and remote ischemia preconditioning group （RIPC group，n=12）. Cardiac function was digitalized and analyzed. The expression of HSP70, PDCD4, B-cell lymphoma/leukemia-2 （Bcl-2） and Bax was detected by Western blotting. The expression of miRNA-1 and miRNA-21 was detected by real-time reverse transcriotion-polymerase chain reaction （RT-PCR）. Assessment of cardiac infarct size and myocardial apoptosis was determined using triphenyltetrazolium chloride （TTC） assay and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay （TUNEL） assay respectively. Results The expressions of miRNA-1 and miRNA-21 were up-regulated in IPC group, but the expression of miRNA-1 was down-regulated in RIPC group and IPO group （P＜0.05）. The expressionsof PDCD4, HSP70 and Bax were down-regulated in ‘conditioning’ groups compared with CON group （P＜0.05）. The expression of Bcl-2 was not statistically different among the four groups. The infarct size and the myocardial apoptosis in ‘conditioning’ hearts were significantly decreased compared with CON group （P＜0.05）. Conclusion The expressions of the miRNA-1 and miRNA-21 are different in IPC, RIPC and IPO groups, and their target proteins are not inversely correlated with the miRNAs in all the ‘conditioning’ groups.
ObjectiveTo investigate whether there is a protecting effect of remote ischemic preconditioning (RIPC) on patients underwent cardiac valvular surgery. MethodWe retrospectively analyzed the clinical data of 72 adult patients underwent cardiac valvular surgery in our hospital from Febuary 2014 through April 2015 year. There were 26 males and 46 females with an age ranging from 23-68 years. We devided 72 patients into a RIPC group and a control group. There were 14 males and 28 females with a mean age of 48.87±12.28 years in the RIPC group. After the induction of anesthesia, the RIPC group was induced by three cycles of right upper limb ischemia and reperfusion using a blood pressure cuff. The blood pressure cuff was inflated to 200 mm Hg and we held it on for 5 minutes, deflated to 0 mm Hg and maintained for 5 minutes, which was defined as one cycle. There were 10 males and 20 females with a mean age of 47.70±8.07 years in the control group. We placed a standard blood pressure gasbag on the right upper limb for 30 minutes without inflation in the control group. We recorded the clinical data including cardiopulmonary bypass (CPB) time, the cross-clamping time of ascending aorta, preoperative ejection fraction (EF), EF after discharging, postoperative complica-tion and mortality. Blood were sampled preoperatively (T0), 30 minutes after RIPC (T1), 30 minutes aftr the cardiopul-monary bypass finished (T2), 24 hours (T3), 48 hours (T4) and 72 hours (T5) after surgery to detect the concentration of troponin T (cTnT) and creatine kinase-MB (CK-MB). We counted the person-time used dopamine and norepinephrine. ResultThere was no death in both groups. The mechanical ventilation time, the time of ICU stay, the time of hospital stay, the number of person used vasoactive agent, and the EF when discharging showed no statistical difference between the two groups. Levels of cTNT in the RIPC group were statistically lower than those in the control group at T2 and T3 (P=0.001, P=0.001). Levels of CK-MB in the RIPC group were statistically lower than those in the control group at T2, T3, and T4 (P=0.011, P=0.010, P=0.033). ConclusionRIPC may have protective effect on myocardium for patients underwent cardiac valvular surgery.
ObjectiveTo systematically review the efficacy of remote ischemic preconditioning in myocardial protection for on-pump CABG patients. MethodsDatabases including PubMed, EMbase, The Cochrane Library (Issue 1, 2015), WanFang Data, CBM and CNKI were searched from inception to January 2015 to collect randomized controlled trials (RCTs) about remote ischemic preconditioning on coronary artery bypass grafting under extracorporeal circulation. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was conducted using RevMan 5.2 software. ResultsA total of 11 RCTs involving 1 128 patients were included. The results of meta-analysis showed that, compared with patients in the control, the RIPC (remote ischemic preconditioning) patients had lower levels of troponin T (MD=-0.22, 95%CI -0.24 to -0.20, P < 0.000 01) and troponin I (MD=-1.91, 95%CI -2.43 to -1.38, P < 0.000 01). However, there were no statistical differences between the two groups in CK-MB, mortality at 30 days, inotropic support, length of stay in ICU or in hospital. ConclusionCurrent evidence indicates that RIPC myocardial protection has little impact on patients undergoing CABG surgery. Due to the quantity and quality limitations of included studies, more high quality studies are needed to verify the above conclusion.
Objective To systematically evaluate the clinical value of remote ischemic preconditioning (RIPC) in elective percutaneous coronary intervention (EPCI). Methods We electronically searched databases including PubMed, EMbase, The Cochrane Library (Issue 6, 2015), WanFang Data, CBM and CNKI from inception to June 2016, to collect randomized controlled trials (RCTs) about RIPC in EPCI. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was performed using RevMan 5.3 software. Results Nine RCTs involving 1 099 patients were included. The results of meta-analysis showed that: There were no significant difference in the level of troponin I and T between the RIPC group and the control group (SMD=–0.24, 95%CI –0.63 to 0.16,P=0.24). Sensitive analysis showed that with 3×5–min remote preconditioning protocol, there was still no significant difference in the level of troponin I and T between the two groups (SMD=–0.16, 95%CI –0.36 to 0.04,P=0.12). Another, RIPC could significantly reduce the incidence of peri–procedural myocardial infarctions (RD=–0.14, 95%CI –0.20 to –0.08,P<0.000 01) and the risk of ST-segment deviation in the elective PCI procedure (RD=–0.17, 95%CI –0.26 to –0.07,P=0.000 6), but there was no significant difference in postoperative eGFR between both groups (SMD=–0.03, 95%CI –0.18 to 0.12,P=0.71). Conclusion RIPC can significant reduce the incidence of peri-procedural myocardial infarctions, and the risk of ST-segment deviation in the elective PCI procedure. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify the above conclusion.
Objective Explore the effect of remote ischemic preconditioning (RIPC) on preoperative heart rate variability in patients with heart valves. Methods From January 2022 to July 2022, screening was conducted among 118 patients based on inclusion/exclusion criteria. Fifty-eight patients were excluded, and 60 patients participated in this trial with informed consent and were randomly divided into a RIPC group (n=30) and a control group (n=30). Due to the cancellation of surgery, HRV data was missing. 7 patients in the control group were excluded, and 5 patients in the RIPC group were excluded, 23 patients in the final control group and 25 patients in the RIPC group were included in the analysis. Comparison of relevant indicators of heart rate variability (standard deviation of NN interval (SDNN), standard deviation of mean value of NN interval in every five minutes (SDANN), mean square root of difference between consecutive NN intervals (RMSSD), percentage of adjacent RR interval>50 ms (PNN50), low frequency component (LF), high frequency component (HF) and LF/HF) at 8 hours in the morning on the surgical day between two groups of patients. Results There was no statistical difference in baseline characteristics between the two groups, and there was no significant difference in heart rate variability 24 hours before intervention (P>0.05). After the intervention measures were taken, the comparison of the results of heart rate variability at 8 hours on the day of operation showed that SDNN and SDANN of patients in the RIPC group were higher than those in the control group, with statistical differences (P<0.05). Conclusion RIPC can stabilize the preoperative heart rate variability of patients undergoing cardiac valve surgery.