Background: The aim of this study was to quantify the contraction of retinal pigment epithelium cells (RPE) induced by bioactive factors in pathological vitreous samples.
Material and methods: Using an in vitro contraction assay, the contraction-stimulating activity of vitreous samples of different vitreoretinal pathologies was evaluated. Transdifferentiated porcine RPE cells were placed on hemispherical type I collagen gel. After exposure to pathological vitreous samples derived from different entities (physiological (n=6), rhegmatogenous retinal detachment (n=11), proliferative vitreoretinopathy (PVR) (=10), proliferative diabetic retinopathy (n=6)) the induced gel contraction was determined.
Results: The specific activity of the unclassified samples was 0.04 (median, range: 0-0.08). Vitreous samples derived from patients diagnosed as having any grade of PVR displayed a specific activity of 0.45 (median, range: 0.03-1.45). Samples removed from patients with rhegmatogenous retinal detachment disclosed a specific activity of 0.13 (median, range: 0.01-0.93). The specific activity of vitreous samples removed from patients with diabetic retinopathy had a specific activity of 0.17 (median, range: 0.06-0.29). The mean specific and total activities of these groups were significantly elevated above the unclassified or baseline values (p<0.05).
Conclusion: Pathological vitreous samples of different vitreoretinal pathologies contain sufficient amounts of biologically active factors to induce extracellular matrix contraction.