Tear Matrix Metalloproteinases and Myeloperoxidase Levels in Patients With Boston Keratoprosthesis Type I

Abstract

Purpose To investigate the tear levels of matrix metalloproteinases (MMPs), myeloperoxidase (MPO) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in eyes after Boston keratoprosthesis type I (B-KPro) implantation and to correlate these markers with established B-KPro prognostic categories. Methods Tear washes were collected from forty patients (seven with autoimmune disease, two with chemical burn and 31 patients with other non-cicatrizing diagnoses). Tear MMPs, MPO and TIMP-1 levels were quantified using multianalyte bead-based enzyme-linked immunosorbent assays. Total MMP activity was determined using a fluorimetric assay. The analytes were compared to underlying diagnosis and other clinical factors. Results MMP-8, MMP-9 and MPO levels were markedly elevated in eyes with B-KPro (80 ± 31 pg/µg, 291 ± 77 pg/µg and 244 ± 33 pg/µg, respectively). Chemical burn was associated with significantly higher tear MMP-8 (474 ± 376 pg/µg) and MMP-9 levels (1300 ± 635 pg/µg) compared to non-cicatrizing diseases (MMP-8: 41 ± 15 pg/µg, p = 0.02 and MMP-9: 196 ± 57 pg/µg, p = 0.02) and higher MMP-9 levels compared to autoimmune diseases (MMP-8: 96 ± 65 pg/µg, p = 0.21 and MMP-9: 306 ± 196 pg/µg, p = 0.04). Similar analyte levels were observed in the B-KPro eye and contralateral non B-KPro eye of patients with bilateral diseases. MMP-8, MMP-9 and total MMP activity correlated strongly with each other. Conclusions In eyes with B-KPro, tear MMP-8 and MMP-9 levels appear related to the underlying ocular surface pathology and not significantly influenced by the presence of the prosthesis.

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