Duration of Remote Ischemic Preconditioning on the Skin Microvascular Response to Local Heating

Remote ischemic preconditioning (RIPC), or intermittent periods of ischemia followed by reperfusion, improves endothelial function in conduit vessels; however, whether functional changes occur in the microvasculature is unknown. Using skin as a microvascular model, we hypothesized that the cutaneous vasodilation (VD) response to localized heating would progressively increase with duration of RIPC treatment. Methods Twelve young adults performed RIPC for two weeks whereas nine completed one week of RIPC. Each RIPC session included 4 repetitions of 5 minutes of arm blood flow occlusion followed by 5 minutes reperfusion. Before and after the RIPC intervention, the skin VD response to localized heating (T loc = 42°C) was measured using laser speckle contrast imaging (LSCI). Data were normalized to cutaneous vascular conductance (CVC); LSCI flux / mean arterial pressure (MAP). Results Baseline CVC and MAP remained unchanged following RIPC (p > 0.05). However, the plateau in the cutaneous VD response to localized heating was augmented after one week of RIPC (Pre: 1.16 ± 0.44, Post: 1.48 ± 0.57 LDF·mmHg −1 ; p < 0.05) but no further improvement was observed after two weeks of RIPC (Pre: 1.50 ± 0.30, Post: 1.63 ± 0.36 LDF·mmHg −1 ; p < 0.05). Delta CVC values (post – pre RIPC) were not different between one week and two weeks of RIPC (p = 0.14). Discussion These data indicate that repeated bouts of RIPC augments cutaneous microvascular function and suggests that the adaptations with repeated RIPC may have an endothelium‐mediated component. And, longer duration of RIPC did not elicit greater functional changes. Support or Funding Information Iowa Space Grant Consortium (NASA STEM Training Grant) (#134819) This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .