AN ELECTRON MICROSCOPIC STUDY OF ULCERATIVE COLITIS

With Special Reference to Characteristic Changes of Capillaries in the Mucosa

Abstract

The fine structure of the mucosal true capillaries in ulcerative colitis (U.C.) was studied by electron microscopy and compared with the appearance of the capillaries in other colonic disorders, mainly morphometrically.
In active U.C., most of endothelial cells showed marked swelling and ballooning, and erythrocytes were seldom found in capillary lumen. These changes suggest increased capillary resistence and decreased vascular flow, and this condition may be involved in microvascular insufficiency of the mucosa. Decrease of numbers of endothelial pinocytic vesicle per unit endothelial cytoplasmic membrane may show hypofunction state of the endothelial cell and replication of the basement membrane around capillaries is indicative of repeated cycles of degeneration and regeneration of endothelial cells.
In remission of U.C., the almost changes mentioned above were between changes of active U. C. and them of irritable bowel syndrome.
Consequently, microvascular insufficiency of the mucosa and the hypofunction state of the endothelial cells may be, at least in part, causes of continuous symptoms and tendency to relapses in U.C..