Changes in cerebral autoregulation and blood biomarkers after remote ischemic preconditioning

Objective To determine the effect of remote ischemic preconditioning (RIPC) on dynamic cerebral autoregulation (dCA) and various blood biomarkers in healthy adults. Methods A self-controlled interventional study was conducted. Serial measurements of dCA were performed at 7 time points (7, 9, and 11 AM; 2, 5, and 8 PM, and 8 AM on the next day) without or with RIPC, carried out at 7: 20 to 8 AM. Venous blood samples were collected at baseline (7 AM) and 1 hour after RIPC, and blood biomarkers, including 5 neuroprotective factors and 25 inflammation-related biomarkers, were measured with a quantitative protein chip. Results Fifty participants were enrolled (age 34.54 +/- 12.01 years, 22 men). Compared with the results on the day without RIPC, dCA was significantly increased at 6 hours after RIPC, and the increase was sustained for at least 24 hours. After RIPC, 2 neuroprotective factors (glial cell-derived neurotrophic factor and vascular endothelial growth factor-A) and 4 inflammation-related biomarkers (transforming growth factor-beta 1, leukemia inhibitory factor, matrix metallopeptidase-9, and tissue inhibitor of metalloproteinase-1) were significantly elevated compared with their baseline levels. Conversely, monocyte chemoattractant protein-1 was significantly lower compared with its baseline level. Conclusions RIPC induces a sustained increase of dCA from 6 to at least 24 hours after treatment in healthy adults. In addition, several neuroprotective and inflammation-related blood biomarkers were differentially regulated shortly after RIPC. The increased dCA and altered blood biomarkers may collectively contribute to the beneficial effects of RIPC on cerebrovascular function.