ABNORMAL NEUROPEPTIDE CONCENTRATION IN RECTAL MUCOSA OF PATIENTS WITHINFLAMMATORY BOWEL-DISEASE

Regulatory neuropeptides are widely distributed in the gastrointestina l tract, where they play an important role in motility, secretion, and immune and inflammatory responses. In this study, the rectal mucosal content of somatostatin (SOM), substance P (SP), beta-endorphin (BE), and thyrotropin-releasing hormone (TRH) was measured by radioimmunoass ay in 56 patients with ulcerative colitis (UC), 15 patients with Crohn 's disease (CD), 15 patients with acute infectious colitis (AIC), and 11 controls, who showed no inflammation of the rectal mucosa, nor abno rmal bowel movements. The content of immunoreactive (ir)-SOM was decre ased in UC patients, especially in those with persistent disease activ ity, while the levels of ir-SP, BE, and TRH were increased in such pat ients. Some changes of ir-peptide levels were also observed in CD and AIC patients. The changes in neuropeptide levels were analyzed in rela tion to histological grades of inflammation in UC patients, grades 4-5 showing the most significant changes. The levels of ir-SOM, SP, BE, a nd TRH showed no significant change in chronic persistent WC when meas ured 6-12 months after the initial examination. In contrast, in patien ts with remitting intermittent UC, the levels of SP and BE decreased d uring remission. Abnormal intestinal neuropeptide content may be impli cated in the continued mucosal immune and inflammatory responses that are manifested in patients with inflammatory bowel disease.