Abstract P214: Mechanotransduction And Uterine Blood Flow In Preeclampsia- The Role Of Piezo 1 Ion Channels

Background: There is a large increase in uterine arterial blood flow during normal pregnancy. Structural and cellular adjustments occur in the uterine vasculature during pregnancy to accommodate this increased blood flow through a process is known as ‘vascular remodeling’. The etiology of preeclampsia involves aberrant placentation and vascular remodeling leading to reduced uteroplacental perfusion. However, the underlying source of the deficient vascular remodeling and the subsequent development of preeclampsia remains to be fully understood. Piezo 1 channels have been shown to be highly expressed in vascular smooth muscle cells of small-diameter arteries and play a role in the structural remodeling of the arteries. Studies have also shown that Piezo 1 is present in uterine arteries and it’s not exclusive to the endothelial cells.

Hypothesis: This study tests the hypothesis that reduced Piezo 1 activity contributes to decreased uterine vascular relaxation in hypertensive pregnant rats.

Methods: Hypertension was induced by treating the pregnant rats with synthetic CpG ODN (ODN 2395) via three intraperitoneal injections (100μg/rats) while the normotensive controls were treated with saline (vehicle) on the 14 th , 17th and 18 th days of pregnancy. Mean arterial pressure (MAP) was measured. In vitro vascular reactivity of uterine arterial (UA) ring segments were evaluated using isometric wire myograph system. Rings were pre-contracted with 3μM phenylephrine (PE), concentration responses of to Yoda1; a pharmacological agonist of Piezo 1 channel were compared. Statistical analysis was performed using nonlinear regression and Students’ t-test.

Results: Our results show that MAP was greater in rats treated with ODN2395 vs untreated rats (112 ± 1 vs 90 ± 1 p =0.0004). Concentration-dependent relaxation responses to Yoda1 were greater in UAs of untreated rats compared to those treated with ODN2395 (EC50 0.06571 ± 0.09781 vs. 0.5774 ± 0.1187 p =0.0018).

Conclusion: These results suggest that the reduced vasodilation in pregnancy-associated hypertension may be due to a reduced Piezo 1 channel activity.