Vasoactive intestinal peptide concentrations and immunocytochemical studies in rectal biopsies from patients with inflammatory bowel disease.

Vasoactive intestinal polypeptide (VIP)-containing nerves and VIP content of endoscopic rectal biopsies from 47 patients with inflammatory bowel disease and 17 normal controls were examined by immunocytochemistry and radioimmunoassay. Immunocytochemistry revealed a consistent increase in, and abnormal appearance of, VIP nerves in patients with Crohn's disease not only those with rectal involvement but also patients with no histological evidence of rectal disease. Normal control biopsies contained 1.64 +/- 0.39 pmol VIP/mg protein as compared with 3.43 +/- 1.24 pmol VIP/mg protein in tissue from patients with rectal Crohn's disease and 5.37 +/- 1.23 pmol VIP/mg protein in those with Crohn's disease without rectal involvement. Ten of the 17 biopsies examined from ulcerative colitics showed a normal pattern of VIP innervation. Examination of the conventional histology of these biopsies showed that only areas with obvious active proctitis had increased VIP nerves and, unlike the appearance in Crohn's disease, these nerves had a normal morphology. The VIP content of these biopsies was similar to that of the controls; 1.34 +/- 0.37 pmol/mg protein.