Lens epithelial cell proliferation in human posterior capsule opacification specimens

In previous in vitro studies on capsular bags it was shown that, after a sh am extracapsular cataract extraction (ECCE) on human donor eyes, lens epith elial cells (LECs) show, in the short term, a dramatically elevated mitotic activity as compared to that in the intact lens. The long term in vivo pro liferation of LECs in human lenses after ECCE and intraocular lens (IOL) im plantation has not been studied until now In the present study, the mitotic activity of LECs in human post-mortem eyes with posterior capsule opacific ation (PCO) was investigated. Human lenses with signs of PCO were dissected from donor eyes and incubated in MEM, supplemented with fetal calf serum, for 1 day (n = 10) or 7 days (n = 9). Six additional specimens were culture d for 7 days after removal of the IOL and lens fibres. After the incubation period, mitotic activity was estimated using the BrdU procedure and the Ki 67 proliferating cell marker. The mean number of BrdU-positive nuclei in the intact PCO specimens was at a level of 7.5 (day 1) and 6.5 (day 7). Removal of the IOL and the lens fib res leads to a ten-fold increase in BrdU positive cells (mean = 84.5). No c orrelation with donor age was found. The Ki67 observations corroborate the BrdU results. The results demonstrate that after an initial rise in proliferative activit y as shown in the capsular bag model, the mitotic activity of LECs returns to a rate comparable to that in intact cultured noncataractous lenses. As i n control lenses, removal of lens fibres significantly elevated the prolife rative activity of the remaining LECs. Suppression by newly formed differen tiated lens fibres in the in vivo capsular bag may be responsible for this return to control levels of mitotic activity of LECs in the PCO specimens. (C) 2000 Academic Press.