Abstract
Purpose: :
Myofibroblasts play a major role in the production of retractile phenomena causing contraction or shrinkage of the epiretinal membranes (ERM) in proliferative vitreoretinopathy or diabetic retinopathy. The presence of α-smooth muscle actin (α-SMA)-positive myofibroblasts and of ED-A fibronectin (FN), one of the the main inducers of myofibroblastic differentiation was studied in idiopathic ERMs and ERM-underlying internal limiting membranes (ILMs).
Methods: :
Samples of ERMs were obtained from 16 patients during vitreoretinal surgery. Double immunofluorescence staining with antibodies recognizing α-SMA and ED-A FN followed by confocal microscopy analysis were performed on ILM-containing ERMs (10 cases) or on ERMs and ILMs separately (6 cases).
Results: :
α-SMA and ED-A FN were detected in all ERMs; ED-A FN was expressed in close relation with α-SMA-positive myofibroblasts. No α-SMA staining was observed in ILM specimens.
Conclusions: :
Macular epiretinal membrane proliferation and contraction induces distortion of the retinal tissue and/or macular edema with visual impairment. Removal of ERM usually leads to a significant regression of retinal folding due to removal of myofibroblasts present within the ERMs and elimination of their associated contractile properties. ILM folding seems to be myofibroblast independent, therefore invalidating the efficiency of ILM peeling.
Keywords: retina • vitreoretinal surgery