Preventive Cold Acclimation Augments the Reparative Function of Endothelial Progenitor Cells in Mice

BACKGROUND/AIMS: Chronic cold exposure may increase energy expenditure and contribute to counteracting obesity, an important risk factor for cerebrocardiovascular diseases. This study sought to evaluate whether preventive cold acclimation before ischemia onset might be a promising option for preventing cerebral ischemic injury. METHODS: After a 14-day cold acclimation period, young and aged mice were subjected to permanent cerebral ischemia, and histological analyses and behavioral tests were performed. Mouse endothelial progenitor cells (EPCs) were isolated, their function and number were determined, and the effects of EPC transplantation on cerebral ischemic injury were investigated. RESULTS: Preventive cold acclimation before ischemia onset increased EPC function, promoted ischemic brain angiogenesis, protected against cerebral ischemic injury, and improved long-term stroke outcomes in young mice. In addition, transplanted EPCs from cold-exposed mice had a greater ability to reduce cerebral ischemic injury and promote local angiogenesis compared to those from control mice, and EPCs from donor animals could integrate into the recipient ischemic murine brain. Furthermore, transplanted EPCs might exert paracrine effects on cerebral ischemic injury, which could be improved by preventive cold acclimation. Moreover, preventive cold acclimation could also enhance EPC function, promote local angiogenesis, and protect against cerebral ischemic injury in aged mice. CONCLUSIONS: Preventive cold acclimation before ischemia onset improved long-term stroke outcomes in mice at least in part via promoting the reparative function of EPC. Our findings imply that a variable indoor environment with frequent cold exposure might benefit individuals at high risk for stroke.