Intestinal adaptation following jejuno-ileal bypass

The changes in functional and excluded loops were studied in two groups of patients at intervals up to 5 years after jejuno-ileal bypass. Macroscopic and histological observations confirmed that the compensatory increase of the absorbing surface of the functioning loop occurs, with an increase in length and width of the loop, hypertrophy of villi and microvilli, and increase in number and geometrical surface of the villous cells. In the excluded intestinal loop, atrophy occurs, evidenced by the reduction in number and size of microvilli, even if the height of villi may appear normal. The bacteriological studies of the functioning and excluded loops show bacterial colonization, which was not constant over the course of time.