PARENTERAL VERSUS ENTERAL NUTRITION - MORPHOLOGICAL-CHANGES IN HUMAN ADULT INTESTINAL-MUCOSA

In animal experiments total parenteral nutrition induces an atrophy of the small intestinal mucosa. In humans morphological data are few and controversial. Therefore, the aim of this study was to investigate th e effect of parenteral nutrition on the intestinal mucosa of human adu lts. For this purpose samples of the proximal jejunum of a) patients w ith chronic pancreatitis receiving total parenteral nutrition as presu rgical treatment, b) enterally nourished patients without (controls) a nd c) with chronic pancreatitis were compared using light and scanning electron microscopy. Statistical differences were assessed applying c omputer-assisted morphometry. The results demonstrated that the thickn ess of the jejunal mucosa decreased already in enterally nourished pat ients with chronic pancreatitis. However, after total parenteral nutri tion the decrease (atrophy) was enhanced due to a strong reduction in villus height albeit the crypt length increased. In addition, scanning electron microscopy revealed distinctive changes in mucosal surface p attern, whereby finger-like villi were replaced by leaf-like villi and by long, winding bifurcating ridges. Cell shedding was absent. In con clusion, total parenteral nutrition in humans induces 1) an atrophy an d 2) a remodelling of the intestinal mucosa (epithelium and lamina pro pria) with a decrease in the absorbing surface. These alterations invo lve both cell proliferation and cell shedding. The response of the muc osa to parenteral nutrition is immediate and the effect of the treatme nt in bringing about morphological alterations is more efficacious at the beginning than in the successive period. The basic disorder (chron ic pancreatitis) of the patients nourished parenterally contributes to mucosal atrophy, but not to remodelling.