Methods to Observe and Weaken the Influence of Pregnancy-Associated Plasma Protein-A on Endothelial Cell Function

Objective: To investigate the effect of pregnancy-associated plasma protein-A (PAPP-A) on hu- man umbilical vein endothelial cell (HUVEC) contraction and relaxation function. We also investigated some effects of pregnancy serum, which was voluntarily provided by women who were 9 months pregnant, on PAPP-A function and endothelial cell function. Methods: HUVECs were cultured in vitro with PAPP- A at 0, 50, 100, and 200 ng/mL for 0, 12, 24, 48 hours. HUVECs were also pretreated for 12 hours with pregnancy serum before in vitro culture in the presence or absence of PAPP-A (50 ng/mL). Nitric oxide (NO) levels in cell supernatants were assessed using spectrophotometry. Endothelin-1 (ET-1) levels were determined using immunohistochemistry assays and quantified by mean optical density (MOD). Results: The NO levels of HUVECs in the PAPP-A groups were significantly lo wer compared to the control group (P<0.05), whereas ET-1 levels in PAPP-A HUVECs were significantly higher compared to the control group (P<0.05.) Additionally, these effects were dose-dependent. The NO levels of HUVECs in the PAPP- A groups with pregnancy serum were higher compared to the control group (P<0.05). ET-1 levels in PAPP- A HUVECs with pregnancy serum were lower than in the control group (P<0.05). Conclusions: PAPP-A may affect HUVEC contraction and relaxation by reducing NO secretion and increasing ET-1 levels. In addition, pregnancy serum may affect PAPP-A function on vascular endothelial cells.