THE EXPRESSION OF GLUTATHIONE TRANSFERASE-MU IN PATIENTS WITH INFLAMMATORY BOWEL-DISEASE

Background: Glutathione transferases (GST) are a group of multifunctio nal enzymes important in the detoxification of many electrophiles and, in addition, fatty acid hydroperoxides, thus limiting tissue damage f rom oxidative free radical attack. Of the four classes of GST (alpha, mu, pi, and theta), a class mu isoenzyme, GST mu, is dominantly inheri ted and is expressed in approximately half of the population. GST mu e xpression was examined in patients with inflammatory bowel disease and correlated to clinical course, extension, and age of onset of the dis eases. Methods: GST mu can be measured as GST activity against bans-st ilbene oxide. This GST activity was measured in whole blood in 179 pat ients with ulcerative colitis, 109 patients with Crohn's disease, and 449 age-matched controls. Results: Frequencies of GST mu expression we re as follows: controls (n = 449, 51.2%), mild ulcerative colitis (n = 76, 47.3%), moderate ulcerative colitis (n = 43, 46.5%), and severe u lcerative colitis (characterized by colectomy) (n = 60, 36.7%). This t rend was, however, not significant (p = 0.094). Patients with onset of the colitis before the age of 30 years (n = 91) had a lower frequency of GST mu expression (35.2%) than patients with a later onset (n = 88 , 52.3%) (p < 0.05). This difference was more pronounced among the col ectomized patients (19.4% versus 55.2%) (p < 0.01). In Crohn's disease , patients with colitis had a lower frequency of GST mu expression (n = 29, 31.0%) than controls; however, this was not statistically signif icant (p = 0.055). No difference was found with regard to age of onset . Conclusion: We conclude that in patients with ulcerative colitis, la ck of GST mu is related to early age of onset and a more severe clinic al course leading to colectomy.