Overexpression of matrix metalloproteinase-1 (MMP-1) and MMP-3 in superior limbic keratoconjunctivitis.

PURPOSE: To explore the presentations of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in superior limbic keratoconjunctivitis (SLK) with typical redundant superior conjunctiva.

METHODS: Eight surgical specimens from medically refractory SLK patients were examined. Another nine conjunctival specimens from patients who underwent cataract and retinal surgery served as controls. Expression of RNA and proteins of MMPs and TIMPs in conjunctival specimens and cultured conjunctival fibroblasts were determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC).

RESULTS: The expression of mRNA of MMP-1 and -3 was detected in six and seven SLK patients, respectively, but was not detected in any case in the control group. IHC showed more prominent immunostaining of MMP-1 and -3 in the subepithelial stroma of the SLK patients than in the controls. After culturing, conjunctival fibroblasts of the SLK patients also shown apparent overexpression of MMP-1 and -3 compared with that in the controls. MMP-9 was not detected in both groups. MMP-2 and TIMP-1 and -2 were detected in some cases in both groups without a statistically significant difference between groups.

CONCLUSIONS: Overexpression of MMP-1 and -3 was found in surgical specimens and cultured conjunctival fibroblasts from SLK patients. MMP imbalance may contribute to SLK pathogenesis. (ClinicalTrials.gov number, NCT00167050.).