In proliferative vitreoretinopathy (PVR), the cellular component primarily responsible for tractional membrane formation on the inner retinal surface (epiretinal membrane) is:
- A Hyalocytes transdifferentiating into myofibroblasts under TGF-β2 stimulation
- B Activated Muller glial cells forming glial scar tissue
- C Retinal pigment epithelial (RPE) cells undergoing epithelial-to-mesenchymal transition (EMT) ✓
- D Blood-derived macrophages and fibrin forming a scaffold
Explanation
PVR membranes contain a heterogeneous population of cells, but RPE cells undergoing epithelial-to-mesenchymal transition (EMT) are the dominant contributors to the tractional membranes. After retinal break formation and vitreoretinal contact disruption, RPE cells (normally a postmitotic monolayer) disperse into the vitreous and subretinal space. Under the influence of growth factors (TGF-β2, PDGF, EGF), they undergo EMT — acquiring myofibroblast-like properties with increased contractility, motility, and collagen synthesis. These transdifferentiated cells form the characteristic star-fold membranes (PVR grade C). Silicone oil is used to tamponade the retina during vitrectomy for PVR because its long-term intraocular presence supports the retina while membrane recurrence occurs.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.