Enzymatic and morphometric evidence for Crohn's disease as a diffuse lesion of the gastrointestinal tract.

Intestinal disaccharidase and dipeptidase activities were measured in mucosal biopsies from the proximal jejunum in 20 patients with Crohn's disease apparently confined to the distal ileum or large bowel, 14 patients with ulcerative colitis, and 14 healthy volunteers who acted as controls. The dissecting microscopy and histological appearance of the biopsies were normal (Gd 0-1) except for two which showed grade 2 changes. tbiopsy morphometry showed a reduction of jejunal mucosal surface area and an increase in mucosal volume in patients with Chron's disease when compared with the other two groups. The mucosal enzymes studies demonstrated that patients with Crohn's disease had a significant reduction in brush-border enzymes (disaccharidase) but no change in cytoplasmic enzyme activity (dipeptidases). The enzyme levels in patients with ulcerative colitis did not differ from the healthy controls. The reduction of brush-border enzymes with normal cytoplasmic enzymes in the presence of abnormal morphometry is further evidence of the concept of Crohn's disease as a diffuse lesion of the gastrointestinal tract. It also suggests that there is either specific damage to the microvilli or some other abnormality such as impairment of enzyme synthesis.