CALL FOR PAPERS Cardiovascular-Renal Mechanisms in Health and Disease Systemic hemodynamic and regional blood flow changes in response to chronic reductions in uterine perfusion pressure in pregnant rats

Sholook MM, Gilbert JS, Sedeek MH, Huang M, Hester RL, Granger JP. Systemic hemodynamic and regional blood flow changes in response to chronic reductions in uterine perfusion pressure in pregnant rats. Am J Physiol Heart Circ Physiol 293: H2080–H2084, 2007. First published July 20, 2007; doi:10.1152/ajpheart.00667.2007.—Preeclampsia (PE) is associated with increased total peripheral resistance (TPR), reduced cardiac output (CO), and diminished uterine and placental blood flow. We have developed an animal model that employs chronic reductions in uterine perfusion pressure (RUPP) in pregnant rats to generate a “preeclamptic-like” state during late gestation that is characterized by hypertension, proteinuria, and endothelial dysfunction. Although this animal model has many characteristics of human PE, the systemic hemodynamic and regional changes in blood flow that occur in response to chronic RUPP remains unknown. Therefore, we hypothesized that RUPP would decrease uteroplacental blood flow and CO, and increase TPR. Mean arterial pressure (MAP), CO, cardiac index (CI), TPR, and regional blood flow to various tissues were measured using radiolabeled microspheres in the following two groups of conscious rats: normal pregnant rats (NP; n 8) and RUPP rats (n 8). MAP was increased (132 4 vs. 99 3 mmHg) in the RUPP rats compared with the NP dams. The hypertension in RUPP rats was associated with increased TPR (2.15 0.02 vs. 0.98 0.08 mmHg ml 1 min ) and decreased CI (246 20 vs. 348 19 ml min 1 kg , P 0.002) when contrasted with NP dams. Furthermore, uterine (0.16 0.03 vs. 0.38 0.09 ml min 1 g tissue ) and placental blood flow (0.30 0.08 vs. 0.70 0.10 ml min 1 g tissue ) were decreased in RUPP compared with the NP dams. These data demonstrate that the RUPP model of pregnancy-induced hypertension has systemic hemodynamic and regional blood flow alterations that are strikingly similar to those observed in women with PE.