Seven Consecutive Days of Remote Ischemic Preconditioning Improved Cutaneous Vascular Reactivity Induced by Post Occlusive Reactive Hyperemia

Abstract

ObjectiveRemote ischemic preconditioning (RIPC), induced by brief periods of ischemia followed by reperfusion, elicits strong cardioprotection from ischemia reperfusion injury in animal models. However, recent clinical trials in humans have yielded mixed results that may be explained by coexisting conditions and other experimental factors. Using human skin as an alternative model to study RIPC, we hypothesized that cutaneous vascular reactivity to post‐occlusive reactive hyperemia (PORH) will be increased following repeated RIPC.MethodsYoung healthy participants (26 ± 1 years; 4 male, 5 female) performed RIPC for seven consecutive days. Each daily RIPC session consisted of 4 repetitions of 5 minutes of upper arm blood flow occlusion interspersed by 5 minutes non‐occlusion. Pre‐ and 24 hours post‐RIPC training, an index of skin microvascular blood flow (i.e., cutaneous red blood cell flux) was measured from the ventral forearm using laser speckle contrast imaging. Flux was measured continuously during baseline, 5 minutes of arm blood flow occlusion with 200 mmHg of cuff pressure, and during 5 minutes of PORH. Peak flux during hyperemia, Max (peak after subtracting baseline), Time to peak (Tp) (index of vascular resistance), Max/Tp (indicator of early vascular changes), and area under curve (AUC) were analyzed from collected data. Data are presented as cutaneous vascular conductance (CVC), which was calculated as flux/mean arterial pressure.ResultsSeven consecutive days of RIPC increased Max/Tp (Pre: 0.10 ± 0.02 vs. Post: 0.12 ± 0.02 CVC/sec, p<0.05). Although not statistically different, other indices of PORH were increased; AUC (Pre: 89.7 ± 13.5 vs. Post: 107.2 ± 10.4 CVC·sec, p=0.10), Peak (Pre: 2.18 ± 0.02 vs. Post: 2.28 ± 0.20 CVC, p=0.33), Max (Pre: 1.68 ± 0.20 vs. Post: 1.79 ± 0.20 CVC, p=0.18), and Time to peak (Tp) (Pre: 18.6 ± 1.1 vs. Post: 17.0 ± 1.3 sec, p=0.11).ConclusionsSeven consecutive days of RIPC augmented cutaneous microvascular reactivity to PORH. Collectively, these data support repeated RIPC as a means to improve microvascular function in humans.All experimental procedures were approved by the Institutional Review Board at Des Moines University and conformed to the standards set by the Declaration of Helsinki (IRB#: 08‐15‐05)Support or Funding InformationFunding source: Des Moines University, IOER #03‐14‐01 (PI: J. Lang)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.