Shear stress-mediated NO production in HPAECs from control and growth restricted pregnancies
HPAECs isolated from control (A; n = 6) and FGR (B; n = 6) placentas were cultured under static or shear stress conditions for 48 h and nitrite concentration measured in flow conditioned media as an indication of nitric oxide production. There was a significant effect of time on nitrite formation in both groups; and at each time point, shear stress increased nitrite production compared to static culture (2-way ANOVA: P < 0.0001, both groups; Bonferonni multiple comparison test: **P < 0.01, ***P < 0.001, ****P < 0.0001, respectively). Nitrite, as a proportionate measure to NO, generated by FGR HPAECs (filled bars) was significantly greater than control HPAECs (open bars) following 48 h exposure to increasing shear stress conditions (C; 2-way ANOVA: P < 0.05; Bonferroni multiple comparison test: **P < 0.01). The production of nitrite, proportionate to NO release, by normal and FGR HPAECs in response to 48 h shear stress (at 20 dyn cm–2) was measured in the presence and absence of l-NNA (100 μm) (D); l-NNA caused a significant reduction only in the FGR group (Sidak’s multiple comparison test: ****P < 0.0001).