Expression of Matrix Metalloproteinases in the Circulating Immune Cells in Children with Helicobacter pylori Infection-Correlation with Clinical Factors.

Abstract

H. pylori gastritis is strongly associated with the upregulation of the expression of several matrix metalloproteinases (MMPs) in the gastric mucosa. However, the role of MMP-2 and MMP-9, and their inhibitors (tissue inhibitors of metalloproteinases -TIMPs) produced by immune cells in infected children have not been clearly defined. Moreover, the effects of H. pylori eradication therapy on MMPs and TIMPs production has not been evaluated. A total of 84 children were studied: 24-with newly diagnosed H. pylori gastritis, 25-after H. pylori eradication therapy (17 of them after successful therapy), 24-with H. pylori-negative gastritis, and 11-controls. Plasma levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 by ELISA; MMPs and TIMPs expression in lymphocytes; neutrophils and monocytes in peripheral blood by multiparameter flow cytometry; and mucosal mRNA expression levels of MMPs and TIMP-1 in gastric biopsies by RT-PCR were evaluated. Children with H. pylori-related gastritis showed the following: (1) increased MMP-2 and TIMP-2 plasma levels, (2) increased intracellular expression of MMP-2 in the circulating lymphocytes and neutrophils, (3) low frequencies of circulating TIMP-1+ and TIMP-2+ leukocytes, and (4) high expression of mRNA for MMP-9 along with low expression of mRNA for MMP-2 in the gastric mucosa. Unsuccessful H. pylori eradication was associated with the following: (1) high plasma levels of MMP-9 and TIMP-1, (2) increased pool of TIMP-1+ lymphocytes as well as high expression of MMP-9 in circulating lymphocytes, and (3) high expression of mRNA for MMP-9 in the gastric mucosa. Our data suggest that MMPs are important contributors to stomach remodelling in children with H. pylori-related gastritis. Unsuccessful H. pylori eradication is associated with increased MMP-9 in plasma, circulating lymphocytes, and gastric mucosa.