Nicotine reduces VEGF-secretion and phagocytotic activity in porcine RPE

Abstract

Smoking is a strong environmental factor for the development of age-related macula degeneration. In this study, we investigated the effects of nicotine on RPE cell function in porcine in vitro models, focussing on cell death, VEGF secretion and phagocytotic ability. For these experiments, perfusion organ culture and primary RPE cell culture were used and exposed to nicotine up to 7 days. Survival was investigated in primary porcine RPE cells in an MTT and trypan blue exclusion assay. VEGF secretion was investigated in a porcine perfusion organ culture model using ELISA. A phagocytosis assay using FITC-labelled latex beads in primary RPE cells was used to assess the phagocytotic ability of the cells. Nicotine does not induce cell death in the RPE at any time point up to 7 days of stimulation at any tested concentration. VEGF secretion, however, is diminished compared to untreated control already after 1 day of nicotine treatment and even more profoundly up to 7 days. Furthermore, phagocytotic ability of the RPE is diminished by nicotine in the highest concentrations tested (100 μM). Nicotine impedes RPE function (VEGF secretion, phagocytosis), which could be directly involved in the development of dry AMD and geographic atrophy.