Interleukin-6 and the matrix metalloproteinase response in the vitreous during proliferative vitreoretinopathy

Purpose: To investigate the levels of IL-6 in the vitreous of patients with RRD complicated with PVR and correlate the IL-6 levels with matrix metalloproteinase (MMP)-1,-2,-3,-8,-9 and tissue inhibitor of metalloproteinases (TIMP)-1 with respect to RRD extent, duration and PVR grade. Design: Cohort study. Participants: Twenty-eight vitreous samples from 28 eyes of 28 patients with RRD complicated with PVR. Methods: Institutional study. Twenty-eight vitreous samples from 28 eyes of 28 patients with RRD complicated with PVR were collected during pars plana vitrectomy (PPV) and were compared to vitreous control samples. IL-6. MMP-1,-3,-8 and TIMP-1 levels were measured using ELISA while enzymatic activity of MMP-2, and -9 was determined employing gelatin zymography. Results: Protein IL-6 (p = 0.030), MMP-1 (p = 0.003), MMP-3 (p = 0.003), TIMP-1 (p = 0.001) levels as well as enzymatic activity of proMMP-9 (p = 0.013), MMP-9 (p = 0.017) and proMMP-2 (p = 0.010), were significantly increased in PVR patients as compared to controls. IL-6 levels correlated with MMP-1 (p = 0.002), proMMP-2 (p = 0.006), MMP-3 (p = 0.001) and TIMP-1 (p = 0.006). Regression analysis revealed positive correlations between IL-6 and all MMPs and TIMP-1. Conclusions: Taking into account the previously established effect of interleukins in MMP activity, the findings of this study suggest a role of IL-6 in MMP stimulation during PVR development. (C) 2011 Elsevier Ltd. All rights reserved.