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, diabetic retinopathy or idiopathic macular epiretinal membranes. The presence of a-smooth muscle actin (a-SMA)-positive myofibroblasts and of ED-A fibronectin (FN), one of the main inducers of myofibroblastic differentiation was studied in internal limiting membranes (ILM) removed during macular hole surgery.
Methods: :
Samples of ILMs following macular hole surgery in 9 eyes were collected. Double immunofluorescence staining with antibodies recognizing a-SMA and ED-A FN followed by confocal microscopy analysis as well as electronic microscopy were performed.
Results: :
a-SMA and ED-A FN were detected in ILM removed in stage III and IV macular holes. ED-A FN was expressed in close relation with a-SMA-positive myofibroblasts predominately located close to the border of the macular hole area. Distally to the hole area the ILM specimens were a-SMA and ED-A FN negative. No a-SMA staining was observed in ILM specimens of stage II macular hole specimens.
Conclusions: :
Scanning electron microscopy indicated that cellular migration was not apparent around the macular hole in the early stage of the development of this pathology.Cellular elements expressing contractile properties related to a-SMA, typical of myofibroblasts differentiation, appear to be present at late stage macular holes.
Keywords: retina • macular holes