Structural Remodeling of the Mouse Gracilis Artery: Coordinated Changes in Diameter and Medial Area Maintain Circumferential Stress

Objective: Vascular networks respond to chronic alterations in blood supply by structural remodeling. Previously, we showed that blood flow changes in the mouse GA lead to transient diameter increases, which can generate large increases in circumferential wall stress. Here, we examine the associated changes in the medial area of the arterial wall and the effects on circumferential wall stress. Methods: To induce blood flow changes, one of the two feeding vessels to the GA was surgically removed. At 7-56days after blood flow interruption, the vasculature was perfused with India ink for morphological measurements, and processed for immuno-cytochemistry to mark the medial cross-section area. Theoretical simulations of hemodynamics were used to analyze the data. Results: During adaptive increases in vessel diameter, increases in medial area were observed, most strongly in the middle region of the artery. Simulations showed that this increase in medial area limits the increase in estimated circumferential stress during vascular adaptation to less than 50%, in contrast to an increase of up to 250% if the medial area had remained unchanged. Conclusions: During vascular adaptation, increases in circumferential stress are limited by growth of the media coordinated with diameter changes.