Transient cardioprotective effects of remote ischemic postconditioning on non-reperfused myocardial infarction: longitudinal evaluation study in pigs

Abstract

BackgroundRemote ischemic postconditioning (RIPostC) has recently emerged as a potential novel therapeutic strategy to achieve protection against acute myocardial infarction (AMI) injury. We aimed to evaluate the longitudinal cardioprotective effects of RIPostC on AMI using 99mTc-MIBI SPECT myocardial perfusion imaging (MPI) and gated 18F-FDG PET (GPET) in pigs. MethodsMI was induced in 12 Chinese pigs. RIPostC was conducted by four 5 min cycles of blood pressure cuff inflation applied to the lower limb immediately after AMI. MPI and GPET were performed longitudinally at baseline, 3rd, 14th, 28th, and 56th days after AMI. Total perfusion defect (TPD), hibernating myocardium (HM), scar, left ventricular (LV) remodeling (End diastolic volume, EDV), and bone marrow (BM) metabolic activity were analyzed, and inflammation biomarkers were measured. ResultsIn outcome evaluation, there was a significant attenuation in TPD (Δ value, at 14th, 28th and 56th days), HM (Δ value, at 14th, 56th days) and Scar (Δ value, at 14th, 28th days) in the RIPostC group compared with the control group (P < 0.05). Additionally, RIPostC attenuated LV enlargement (ΔEDV, at 14th day) (P < 0.05) in comparison to controls. BM 18F-FDG uptake activity in the RIPostC group was lower than the control group (P < 0.05) at the 3rd day after AMI. There was a non-statistically significant trend of decreased MMP-2 levels in the RIPostC group post-AMI (P > 0.05). ConclusionsRIPostC presented the longitudinal cardioprotective effects by preserving myocardial viability, reducing infarct size, attenuating LV remodeling at early stage post-AMI, and may also have an anti-inflammatory effect at the acute phase.