Decreased brush border hydrolase activities without gross morphologic changes in human intestinal mucosa after prolonged total parenteral nutrition of adults.

Animal experimentation with total parenteral nutrition (TPN) has revealed the occurrence of atrophy of the intestinal mucosa and decreased enzyme activities of the brush border, notably the disaccharidases. These findings have heretofore not been confirmed in human investigation. We performed endoscopic biopsies in the third part of the duodenum in 7 adults before TPN, after 21 days of TPN, and after a progressive oral refeeding. We noted a clear-cut decrease of major enzyme activities during TPN (sucrase, maltase, lactase, glucoamylase, acid aminopeptidase, dipeptidyl peptidase) without any morphologic modifications as observed with standard histology. Electron microscopy showed a slight but significant decrease in the height of microvilli. The decreased enzyme activities were rapidly restored after oral refeeding. Thus, the functional consequences of the modifications observed during medium-term TPN in adults are probably limited.