Higher concentration of matrix-metalloproteinase 1 (interstitial collagenase) in H. pylori-compared to NSAID-induced gastric ulcers

Background/Objective: Matrix metalloproteinases (MMPs) are implicated in th e tissue destruction associated with inflammatory diseases. We postulated a causal involvement of MMP-1 in ulcerogenesis and quantified therefore the MMP-1 concentrations in biopsies of human gastric ulcers and the surroundin g mucosa. Further, we correlated them with the individual ulcer etiology. Methods: During upper endoscopy biopsy specimens of the ulcer and surroundi ng normal mucosa were taken from 45 patients with gastric ulcers of differe nt etiology (Helicobacter pylori, NSAID-intake, both or none of these). MMP -1 concentration was measured using a MMP-1 ELISA in 35 patients, western b lot was performed in the remaining 10 patients. Results: In general, median expression of MMP-1 in the ulcer tissue was significantly increased compar ed to the surrounding mucosa (16.8 [4.7-33.4] vs. 10.9 [2.8-17.8] ng/mg pro tein) (p<0.001). Western blot analysis revealed increased concentration of the active forms of MMP-1 in ulcer tissue. Interestingly, the MMP-1 concent ration was significantly higher in 15 H.p.-induced ulcers compared to 19 NS AID-induced ones: 19.3 (8.3-33.2) vs. 11.4(4.7-33.4) ngl mg protein, p = 0. 0354). Conclusion: MMP-1-expression in the ulcer tissue depends on the ulcer etiol ogy. However, MMP-1 does not seem to be causally involved in ulcerogenesis. In NSAID-induced ulcers the MMP-1-synthesis may be suppressed by NSAID-ind uced decrease of mucosal prostaglandin concentration.