LAUSR

BACKGROUND AND PURPOSE Capillary arterialization, characterized by the coverage of pre-existing or nascent capillary vessels with vascular smooth muscle cells (VSMCs), is critical for the development of collateral arterioles to improve post-ischemic blood flow. We previously demonstrated that the inhibition of transient receptor potential canonical 6 (TRPC6) channels facilitates contractile differentiation of VSMCs under ischemic stress. We here investigated whether TRPC6 inhibition promotes post-ischemic blood flow recovery through capillary arterialization in vivo. EXPERIMENTAL APPROACH Mice were subjected to hindlimb ischemia by ligating left femoral artery. The recovery rate of peripheral blood flow was calculated by the ratio of ischemic left leg to non-ischemic right one. The number and diameter of blood vessels were analyzed by immunohistochemistry. Expression and phosphorylation levels of TRPC6 proteins were determined by western blotting and immunohistochemistry. KEY RESULTS Although the post-ischemic blood flow recovery is reportedly dependent on endothelium-dependent relaxing factors, systemic TRPC6 deletion significantly promoted blood flow recovery under the condition that nitric oxide or prostacyclin production was inhibited, accompanying capillary arterialization. Cilostazol, a clinically approved drug for peripheral arterial disease, facilitates blood flow recovery by inactivating TRPC6 via phosphorylation at Thr69 in VSMCs. Furthermore, inhibition of TRPC6 channel activity by Pyrazole-2 promoted post-ischemic blood flow recovery in apolipoprotein E-knockout mice. CONCLUSION AND IMPLICATIONS Suppression of TRPC6 channel activity in VSMCs could be a new strategy for the improvement of post-ischemic peripheral blood circulation.