Increased arterial wall volume following chronic reduction of blood flow

Abstract

Vascular networks respond to chronic alterations in blood supply by structural remodeling. A previous study showed that the diameter of the mouse gracilis artery increased transiently following a permanent reduction in blood flow, with a peak at 21 days. Here, the objective was to investigate whether the diameter increase is accompanied by increased vessel wall mass in the same experimental setting. Blood flow reduction was induced by removing a portion of the saphenous artery, one of the two blood supplies of the gracilis artery. After 21 days, the vasculature was perfused with India ink for diameter measurements, embedded in paraffin, sectioned and processed for immunocytochemistry using fluorescently labeled anti smooth muscle alpha-actin antibody and bisbenzimidazole (BBI) to mark cell nuclei. The remodeled vessel wall volume was almost doubled relative to the control, and the number of smooth muscle cell nuclei increased significantly. The results are consistent with the concept that outward remodeling causes increased circumferential wall stress, which then stimulates vessel wall growth to restore circumferential stress to near its initial level. Supported by AHA Grant 0010189Z and NIH Grants HL34555 and HL63732.