[Ultrastructure of diabetic autonomic neuropathy of the gastrointestinal tract].

Gastrointestinal motility disorders induced by diabetes mellitus are most commonly manifested in the colon, and are considered to be an expression of diabetic autonomic polyneuropathy. In this study, for the first time, the intrinsic nervous system of the bowel has been subjected to an ultrastructural and morphometric examination in rectal biopsy material obtained from diabetics with and without diabetic enteropathy. In patients with diabetic enteropathy, the nerves of the submucous plexus (Meissner's plexus) revealed significant swelling of the axons, as an expression of neural degeneration. Furthermore, in about a half of these patients, thickening of the basal membrane of Schwann's cells was also detected. Additional, although unspecific, changes found in the diabetics were a quantitative increase in the lysosomes, lipofuscin and glycogen in the Schwann cells. The ultrastructural findings represent evidence for the presence of an intrinsic autonomic polyneuropathy in diabetics with diabetic enteropathy. At the same time, they indicate that the diagnosis of diabetic enteropathy is no longer merely an "exclusion" diagnosis.