Local Heating Mediated Vasodilation Increased 48 Hours After Remote Ischemic Preconditioning

Abstract

IntroductionRemote ischemic preconditioning (RIPC), induced by brief periods of blood flow occlusion to a limb followed by reperfusion, protects distant tissues from ischemia‐reperfusion (IR) injury. A single bout of RIPC confers a delayed window of protection that begins 24 hrs after RIPC and last for 2–3 days; however, whether this timeline also applies to the microvasculature is unclear. We hypothesize that the hyperemic response to local heating will increase after a single bout of RIPC.MethodsSixteen healthy, young adults (7M, 9F) underwent a single session of RIPC, which consisted of four periods of inflating an arm cuff to 200mmHg for five min interspersed with five min of reperfusion. Laser speckle contrast imaging (LSCI) was used to measure the hyperemia response to local skin heating (Tsk = 42°C) at five time points; before treatment, and 24, 48, 72, and 168 hrs post‐RIPC. LSCI data are expressed as cutaneous vascular conductance (CVC = LSCI flux/mean arterial pressure).ResultsCompared to pre‐RIPC (1.58 ± 0.09 flux · mmHg−1), the vasodilation response to local heating was increased only at the 48‐hr post‐RIPC time point (24 hrs: 1.59 ± 0.10, 48 hrs: 1.69 ± 0.10, 72 hrs: 1.54 ± 0.13, 160 hrs: 1.53 ± 0.11 flux · mmHg−1).ConclusionThese results indicate that the modest increase in local‐mediation dilation exhibited a delayed response that peaked 48 hrs following a single RIPC bout. This suggests that a single bout of RIPC may have a protective effect on the microvasculature.Support or Funding InformationNASA – Iowa Space Consortium Grant