Expression of glutamine synthetase and cell proliferation in human idiopathic epiretinal membrane

Background/aim: The mechanisms of the cellular origin and cell proliferation in the idiopathic epiretinal membrane ( ERM) are unsolved. The aim of this study was to examine the expression of cell cycle related molecules and glutamine synthetase ( GS), which is expressed in Muller cells and their processes, in ERM tissues. Methods: The ERMs were surgically removed using pars plana vitrectomy. Formalin fixed, paraffin embedded ERM tissues were analysed by immunohistochemistry with anticyclin D1, p27 ( KIP1), proliferating cell nuclear antigen ( PCNA), and GS antibodies. Results: The histopathological findings showed that all the ERMs consisted of oval or spindle mononuclear cells with thin collagen-like tissues. Immunoreactivity for GS was detected in collagen-like tissues of ERM, presenting a continuous, isodense pattern. GS immunopositive cells in all cases expressed PCNA in their nuclei. Nuclear immunoreactivity for cyclin D1 was noted in the ERM constituent cells, whereas p27 ( KIP1) positive nuclei were not detected. Conclusion: Cyclin D1 and PCNA were expressed in the idiopathic ERM, which was mainly derived from Muller cells and extensions of their processes.