Comparative analysis of the expression of metalloproteases and their inhibitors in resected crohn's disease and complicated diverticular disease.

Background: Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), are expressed in the gastrointestinal tract by different cellular types. Nevertheless, the imbalance between MMPs and TIMPs plays an important role in the physiopathology of diverse intestinal inflammatory processes.

Methods: An immunohistochemical study was performed using tissue arrays and specific antibodies against MMPs -1, -2, -7, -9, -11, -13, -14, and TIMPs -1, -2 and -3. Immunohistochemical staining of intestinal samples from surgical interventions from 30 patients with complicated Crohn's disease (CD) and 25 patients with diverticulitis were performed at the inflamed mucosa and in adjacent noninflamed mucosa. A reverse-transcription polymerase chain reaction (RT-PCR) analysis was performed to confirm the results obtained by immunohistochemistry. In addition, western blot experiments were carried out.

Results: CD inflamed mucosa showed higher global expression of MMP-2, MMP-9, and MMP-13 than diverticulitis inflamed mucosa. However, inflamed and noninflamed diverticulitis mucosal samples showed higher global expression of MMP-1, TIMP-1, and 3 than the CD samples. Epithelial cells of inflamed mucosa showed higher expression of MMP-2, 9, and 13 in CD than diverticulitis. However, the latter showed higher expression of TIMP-1. Similar differences for fibroblast-like cells and mononuclear inflammatory cells were found. CD samples presented an increased expression of MMPs and a decreased expression of TIMPs compared to diverticulitis.

Conclusions: These results indicate a differential pattern of expression of MMPs and TIMPs in CD and diverticulitis and the necessity to study the potential role of MMP inhibitors as new protective agents in both diseases.