Programmed cell death (apoptosis) in excised subretinal neovascularizations

Background: The occurrence of apoptosis in choroidal neovascularizations (C NV) has only been described previously in a few cases. However, little is k nown about the extent and function of apoptosis. We analyzed the incidence of apoptosis in order to find new options in the therapy of CNV. Particular attention was given to the length of time that the process existed before surgery in patients with age-related macular degeneration (AMD). Patients and methods: In 34 patients (18 women, 16 men) ranging in age from 20 to 91 years (mean 70.3 years),CNV was detected by angiography. The majo rity of patients (n=29) with CNV had AMD, which in most patients affected b oth eyes. In two patients CNV was due to post-traumatic proliferative vitre oretinopathy, in two other patients CNV occurred after a penetrating bulbus injury, and in one patient pseudoxanthoma elasticum was found. Thirty-four CNV membranes were excised by pars plana vitrectomy via retinotomy, fixed in formalin and embedded in paraffin. Sections were stained with PAS and H& E and examined microscopically. The in situ cell-detection kit (TUNEL) was used for immunhistochemical detection of apoptotic cells from fragmentated DNA. Results: In 74% (n=25) of all patients and in 76% (n=22) of patients with A MD,disseminated or focal apoptotic cells were detectable in the connective tissue, retinal pigment epithelium and in the vascular endothelium. in AMD patients with apoptotic cells, the SNV existed 1-12 months (mean 5.5 months ) before surgical intervention. In patients without apoptotic cells, the CN V were present 5-36 months (mean 17 months) before surgery. At the time of surgery, the loss of reading ability had on average been going on 3 months; in patients with apoptotic cells, the mean time from the onset of this sym ptom was 2.4 months (1 week to 11 months); and in patients without apoptoti c cells it was 5 months (1-12 months). Conclusion: Programmed cell death as a regulating pathomechanism was observ ed in all tissue parts of CNV with variable extension. In patients with AMD , a correlation existed between the length of time that CNV existed before surgery and the incidence of apoptotic cells. Apoptosis was found more freq uently in recent CNV than in long-standing lesions. The various activity fo und in CNV suggests that the success of treatment may depend on the moment of intervention. To characterize the role of apoptosis further inducing and inhibiting factors have to be analyzed.