UC San Diego

Objectives: Eosinophilic esophagitis (EoE) is a chronic, antigen-mediated disease in children and adults associated with substantial esophageal remodeling and fibrosis. The expression of the remodeling-associated matrix metalloproteinases (MMPs) has not been previously detailed in EoE. Methods: MMP-2 and-14 expression and cellular localization were assessed using real-time quantitative polymerase chain reaction and immunohistochemistry/immunofluorescence in EoE fibroblasts, active and inactive pediatric EoE biopsies, and nondiseased control biopsies. The effect of transforming growth factor (TGF)-b1 treatment on MMP-2 expression in cultured esophageal epithelial (HET1A) cells was analyzed. Results: MMP-2 and-14 mRNA were expressed in EoE fibroblasts and biopsies. Proliferating epithelial cells produced MMP-14 more abundantly in EoE than in controls (P<0.001) and the degree of epithelial MMP-14 expression correlated positively with basal zone hyperplasia (r=0.65, P=0.002). EoE lamina propria had higher numbers of MMP-2-and-14-positive cells (906±167 and 701±93 cells/mm2) as compared with controls (258±93 cells/mm2, P<0.01 and 232±54 cells/mm2, P<0.01), and MMP-14 expression correlated with the severity of fibrosis. Following therapy with topical corticosteroids, MMP-14 and-2 were significantly diminished (P<0.01). TGF-b1 increased the expression and secretion of MMP-2 from esophageal epithelial HET1A cells. Conclusions: MMP-2 and-14 are elevated in pediatric patients with EoE and significantly decrease following topical corticosteroid therapy. TGF-b1 increases MMP-2 in esophageal epithelial cells. This alludes to previously unappreciated role for MMPs in EoE-associated esophageal remodeling and a potential positive feedback loop via TGF-b1.