Mechanism of PEDF promoting the proliferation of lens epithelial cells in human eyes

ObjectiveTo investigate the regulation effect of pigment epithelium-derived factor (PEDF) on the growth of human lens endothelial cells (LECs) and related mechanisms in vivo and in vitro.MethodsIn the part of in vivo study, 82 eyes of 82 patients with age-related cataract were included to collect the central lens anterior capsule (diameter at 5.0–5.5 mm) with the informed consent of surgery for patients. The selected specimens were divided into the LECs low density group and high density group with 20 specimens for each group based on hematoxylin and eosin staining results. The relative expression level of PEDF mRNA in LECs was detected by reverse transcription PCR. In the part of in vitro study, LEC line (HLE-B3) was cultured and 50 ng/mL PEDF was added in media for 72 h in PEDF culture group, while normally cultured cells were used as the control group. The percentage of LECs at G0 and S phases and apoptotic rate of cells were assayed by using flow cytometry with annexin Ⅴ-FITC/7-AAD double staining method. Intracellular expression of vascular endothelial growth factor (VEGF) mRNA was detected by real-time fluorescence quantitative PCR.ResultsThe central anterior subcapsular LECs density and relative expression level of PEDF mRNA were lower than those of high density group. There were no significant differences between two groups (P = 0.168). The apoptotic rate in the PEDF culture group was significantly reduced in comparison with the control group (P < 0.001). In addition, the expression level of VEGF mRNA was lower in the PEDF culture group compared with the control group (P < 0.001).ConclusionsIn human eyes, PEDF may function as cytotropic factor to promote survival of LECs through anti-apoptosis and reducing-expression of VEGF. Decrease of PEDF content in LECs probably modulates the pathophysiological process of lens cells and further cataractogenesis.