Kim Jahyun, Franke Warren D, Lang James A
Department of Kinesiology, California State University, Bakersfield, Bakersfield, CA, United States.
Department of Kinesiology, Iowa State University, Ames, IA, United States.
Front Physiol. 2022 Mar 14;13:852966. doi: 10.3389/fphys.2022.852966. eCollection 2022.
The optimal frequency and duration of remote ischemic preconditioning (RIPC) that augments microvascular function is unknown. A single bout of RIPC increases cutaneous endothelial function for ∼48 h, whereas 1 week of daily RIPC bouts improves more sustained endothelium-independent function. We hypothesized that 3 days of RIPC separated by rest days (3QOD RIPC) would result in sustained increases in both endothelium-dependent and endothelium-independent functions. Cutaneous microvascular function was assessed in 13 healthy young participants (aged 20.5 ± 3.9 years; 5 males, 8 females) before 3QOD and then 24, 48, and 72 h and a week after 3QOD. RIPC consisted of four repetitions of 5 min of blood flow occlusion separated by 5 min of reperfusion. Skin blood flow responses to local heating ( = 42°C), acetylcholine (Ach), and sodium nitroprusside (SNP) were measured using laser speckle contrast imaging and expressed as cutaneous vascular conductance (CVC = PU⋅mmHg). Local heating-mediated vasodilation was increased 72 h after 3QOD and the increased responsivity persisted a week later (1.08 ± 0.24 vs. 1.34 ± 0.46, 1.21 ± 0.36 PU⋅mmHg; ΔCVC, pre-RIPC vs. 72 h, a week after 3QOD; = 0.054). Ach-induced cutaneous vasodilation increased a week after 3QOD (0.73 ± 0.41 vs. 0.95 ± 0.49 PU⋅mmHg; ΔCVC, pre-RIPC vs. a week after 3QOD; < 0.05). SNP-induced cutaneous vasodilation increased 24 h after 3QOD (0.47 ± 0.28 vs. 0.63 ± 0.35 PU⋅mmHg; ΔCVC, pre-RIPC vs. 24 h; < 0.05), but this change did not persist thereafter. Thus, 3QOD induced sustained improvement in endothelium-dependent vasodilation but was not sufficient to sustain increases in endothelium-independent vasodilation.
增强微血管功能的远程缺血预处理（RIPC）的最佳频率和持续时间尚不清楚。单次RIPC可使皮肤内皮功能增强约48小时，而每日进行RIPC一周可改善更持久的非内皮依赖性功能。我们假设，间隔休息日进行3天的RIPC（3天1次RIPC）会使内皮依赖性和非内皮依赖性功能持续增加。在13名健康年轻参与者（年龄20.5±3.9岁；5名男性，8名女性）中，在3天1次RIPC之前、之后24、48和72小时以及3天1次RIPC后一周评估皮肤微血管功能。RIPC包括4次重复的5分钟血流阻断，中间间隔5分钟再灌注。使用激光散斑对比成像测量皮肤血流对局部加热（=42°C）、乙酰胆碱（Ach）和硝普钠（SNP）的反应，并表示为皮肤血管传导率（CVC = PU·mmHg）。3天1次RIPC后72小时，局部加热介导的血管舒张增加，且增加的反应性在一周后持续存在（1.08±0.24 vs. 1.34±0.46，1.21±0.36 PU·mmHg；ΔCVC，RIPC前与3天1次RIPC后72小时、一周后比较；=0.054）。3天1次RIPC后一周，Ach诱导的皮肤血管舒张增加（0.73±0.41 vs. 0.95±0.49 PU·mmHg；ΔCVC，RIPC前与3天1次RIPC后一周比较；<0.05）。3天1次RIPC后24小时，SNP诱导的皮肤血管舒张增加（0.47±0.28 vs. 0.63±0.35 PU·mmHg；ΔCVC，RIPC前与24小时比较；<0.05），但此后这种变化未持续。因此，3天1次RIPC诱导内皮依赖性血管舒张持续改善，但不足以维持非内皮依赖性血管舒张的增加。
