Photoreceptor apoptosis in human retinal detachment

Although photoreceptor cell apoptosis has been demonstrated in various animal models of retinal detachment (RD), little is known about its occurrence in human RD. We sought to determine whether human photoreceptor cells undergo apoptosis in response to primary and recurrent RD.

Prospective, clinical-pathologic, case series.

Retinal tissue fragments excised during the course of vitreous surgery for RD and recurrent RD were frozen, cut into 4-mum sections, and analyzed using a TdT-dUTP terminal nick-end labeling assay for cell apoptosis. The onset of patient symptoms was used to estimate the duration of the RD.

There were eight patients with primary RD and four patients with recurrent RD enrolled in this study. Duration of RD ranged from 1 to 180 days in the primary RD group, and 2 to 15 days in the recurrent RD group. All retinal tissue specimens had TUNEL-positive cells localized to the outer nuclear layer of the retina, consistent with the localization of photoreceptor cell bodies. TUNEL-positive cells were first identified at 24 hours, peaked by 2 days, and dropped to a low level by 7 days after RD. Recurrent RD induced a greater number of TUNEL-positive cells/mm(2) in the ONL compared with primary RD at corresponding timepoints after the onset of RD.

In response to primary and recurrent RD, human photoreceptor cells follow a pattern of apoptosis that is similar to that seen in animal models of RD. This study suggests that photoreceptor cell apoptosis may be one of the causes of reduced vision after RD, especially those that involve the macula. Drugs that inhibit photoreceptor apoptosis may help improve the final visual prognosis of patients with RD.