Correlation of matrix metalloproteinase levels with the grade of proliferative vitreoretinopathy in the subretinal fluid and vitreous during rhegmatogenous retinal detachment

. Purpose:  We investigated the activity of matrix metalloproteinase (MMP)-2 and -9 and their latent pro-forms (proMMP-2, -9), and protein levels of MMP-1, -3, -8 and tissue inhibitor of MMPs (TIMP)-1 in the subretinal fluid (SRF) and vitreous of patients with rhegmatogenous retinal detachment (RRD). Potential correlations with proliferative vitreoretinopathy (PVR) grade were determined. Methods:  Thirty-seven SRF and 32 vitreous samples from RRD patients and nine vitreous samples from human organ donors (controls), were collected and assayed for MMP-1, -3, -8/TIMP-1 levels using enzyme-linked immunosorbent assay (ELISA), and for proMMP-2, -9, MMP-2, -9 activity employing gelatine zymography. Results:  ProMMP-2, -9, MMP-1, -3, -9, TIMP-1 were significantly higher in the SRF and vitreous of RRD patients compared to the vitreous of organ donors. MMP-8 levels were higher in RRD patients’ SRF. Regarding PVR grade, MMPs and TIMP-1 were differentially present in SRF and vitreous. PVR grade correlated significantly with the levels of MMP-2 in SRF, while proMMP-2, MMP-1, -2, -3, -8, -9 and TIMP-1 levels correlated with PVR grade in the vitreous. Conclusion:  MMP/TIMP-1 levels are elevated in SRF and vitreous during RRD. Significant correlations between PVR grade and MMP-2 in SRF and proMMP-2, MMP-1, -2, -3, -8, -9 and TIMP-1 levels in vitreous were revealed. Investigation of MMP activity in vitreous may provide more valid conclusions compared to SRF pertaining to the role of the MMPs during RRD. The observations of the present study suggest a possible role for MMPs and TIMP-1 in PVR pathophysiology.