The effects of inflammation and acidosis on placental blood vessels reactivity

Introduction: Inflammation and acidosis are two stress stimuli that correspond to pathophysiological processes occurring in placental-mediated vascular disorders. We aimed to investigate the effects of these stimuli on placental chorionic blood vessels reactivity using the ex-vivo placental perfusion model.

Methods: Term placentas were obtained immediately after cesarean deliveries, and selected cotyledons were cannulated and dually perfused ex-vivo. Placentas were perfused with three different protocols: culture medium (M199-controls, n = 5), culture medium with lipopolysaccharide (inflammatory stimuli) (LPS,1 μg/ml, n = 7), and acidotic culture medium (M - 199, pH: 6.9-7, n = 6). Each perfusion experiment was maintained for 180 min. Fetal perfusion pressure was continuously measured. Measurements in response to angiotensin II (AT II) at the end of the perfusion were compared between the treatment groups, including amplitude of the contraction response, relaxation factor, time to maximal constriction and the area under the pressure curve (AUC).

Results: In response to ATII there was a significant difference in the amplitude of the contraction and the AUC between the treatment groups, (p = 0.049, p = 0.015, respectively). As compared with control perfused cotyledon, the inflammatory stimuli significantly increased the vasoconstriction response to ATII in fetal placental blood vessels, as expressed by increased AUC - median (IQR): 555 (235-1184) vs. 133 (118-207), respectively, p = 0.017. The time to maximal constriction and the relaxation factor did not differ between the groups.

Discussion: Inflammatory stimuli but not acidosis impact fetal-placental vasculature in response to ATII, suggesting that inflammation can compromise vascular function.