Abstract P225: Rupp Rat Model Cd4+ T Cells Activate Nk Cells And Cause Mitochondrial Oxidative Stress And Hypertension In Normal Pregnant Rats

Abstract

Preeclampsia (PE) is new onset hypertension during pregnancy and is associated with elevated inflammatory response such as CD4+ T cells, NK cells, and cytokines. We have previously shown women with PE exhibit increases in circulating and placental CD4+T cells and placental mitochondrial (mt) dysfunction/ROS compared to normal pregnant (NP) women. The Reduced Uterine Perfusion Pressure (RUPP) rat model produces many characteristics of PE such as hypertension, increases in CD4+ cells, increases in renal and placental NK cells, and mt dysfunction/ROS. We have previously demonstrated that RUPP CD4+T cells cause hypertension in NP rats, however the role of RUPP CD4+ T cells in stimulating NK cells to cause mt dysfunction/ROS are not elucidated. Therefore, we examined the effect of adoptive transfer of RUPP CD4+ T cells to activate NK cells in NP rats. Splenic CD4+ T cells were isolated from RUPP rats, cultured, and injected into NP rats on GD 13. On GD19, MAP values and blood/tissue samples were collected from both RUPP CD4+ T cell recipients and NP controls. Mitochondrial respiration and mtROS were measured in isolated mitochondria using the Oxygraph 2K and fluorescent microplate reader, respectively. A student’s t-test was used for statistical analysis. On GD19, MAP increased to 110±2 mmHg (n=13) in RUPP CD4+ T cell recipients compared to control NP rats 102±2 mmHg (n=7, p<0.05). Circulating cytolytic NK cells increased to 3±0.6% in RUPP CD4+ T cell recipients (n=8) compared to NP controls 0.3±0.2% (n=7, p<0.05). Placental state 3 (209.3±31.3 vs 422.7 ±83.3 pmol/sec/mg, p<0.05) and maximal (152.1±46.2 vs 229.7±58.9 pmol/sec/mg) and renal state 3 (133.4 ±21.4 vs 289.8±43.4 pmol/sec/mg, p<0.05) and maximal (61.8±18 vs 242.4±27.7 pmol/sec/mg, p<0.05) respiration rates, indicative of ATP production and electron transport chain efficacy respectively, were reduced with RUPP CD4+ T cells (n=6; n=9) compared to NP (n=5; n=5). Collectively, the data indicate that the adoptive transfer of RUPP CD4+ T cells stimulates cytolytic NK cells and placental and renal mitochondrial dysfunction/ROS during pregnancy as important mechanisms of hypertension in the pathophysiology of preeclampsia. Keywords: Preeclamspia, Hypertension, Oxidative stress