APOPTOTIC CELL-DEATH IN PROLIFERATIVE VITREORETINOPATHY

Apoptosis is a selective event of physiological cell deletion that pla ys a crucial role in the development of numerous tissues, including th e retina. In this paper we report the occurrence of apoptosis in epire tinal membranes derived from patients with proliferative vitreoretinop athy (PVR). Detection of apoptosis was performed by an in situ DNA-end -labeling technique using terminal transferase-mediated deoxyuridine t riphosphate (dUTP) incorporation. Apoptotic nuclei exhibiting chromati n condensation and fragmentation were also identified by acridine oran ge fluorescence. Apoptosis was detected in varying numbers of cells. T he typical appearance of apoptotic nuclei, including nuclear chromatin condensation, was detected scattered inhomogeneously throughout the e piretinal membranes, in clusters, or even in single cells. Induction o f apoptosis in human retinal pigment epithelial (RPE) cells by daunomy cin could be demonstrated by in situ DNA end labeling and by quantitat ive determination of cytoplasmatic histone-associated DNA fragments us ing a photometric enzyme immunoassay. Since apoptosis has been shown t o be an important factor in the growth control of various untransforme d and neoplastic cell populations, the pharmacological induction of ap optosis in epiretinal membranes could result in a new approach toward inhibiting cellular proliferation in PVR.