Ultrastructural alterations of collagen fibrils in blood vessel walls.

With increasing concern for elucidation of the role of connective tissues in degenerative diseases of blood vessels, an ultrastructural study was conducted on collagen fibrils of intimal proliferation in experimental autogenous venous pouch aneurysms in rabbits and in atherosclerotic human arteries. The fibrils were compared morphometrically with adventitial collagen as controls. In intimal proliferation from both species intimal collagen fibrils displayed increased variation in shape and size when compared to adventitial collagen fibrils. The abnormal fibrils resembled those of inherited connective tissue diseases, indicating that the changes in collagen fibrils can be acquired and that hemodynamic stress is likely to contribute to their occurrence.