Adaptation of Arterioles in Ischemic Disease

The arterioles of the microcirculation can function as conduit arteries following an arterial occlusion, when arcade arterioles (i.e. anastomosing arterioles) form natural bypasses known as collaterals. The enlargement of arterial collaterals improves the prognosis of patients with ischemic disease, and these clinically significant structures are studied in rodents by ligating the feed arteries to skeletal or cardiac muscle. These images were captured 7 days after ligating the lateral feed artery of the spinotrapezius muscle. The left image depicts the collateral with its paired venule at rest, and the right image shows the same collateral after stimulating it to vasodilate and increase blood flow during muscle contraction (right). Images contributed Kenneth Gouin in the laboratory of Trevor Cardinal at Cal Poly.