Placental ischemia is believed to be the initial event in the development of preeclampsia. Mitochondrial dysfunction is a cause of reactive oxygen species (ROS) generation and oxidative stress, however, there are not many studies examining the role of mitochondrial ROS in the pathology of preeclampsia. The purpose of this study was to not only examine the effect of placental ischemia on mitochondrial-mediated oxidative stress in reduced uterine perfusion pressure (RUPP) rat model of preeclampsia but to also examine the role of mitochondrial ROS in contributing to hypertension in response to placental ischemia. Female pregnant Sprague Dawley rats were used in this study. On gestational day 14, RUPP surgery was performed. On gestational day 19, blood pressure (mean arterial pressure) was measured, placentas and kidneys were collected from normal pregnant and RUPP rats and processed for mitochondrial respiration, ROS, and oxidative phosphorylation enzyme activities. Renal and placental complex activities, expressions and respiration rates were significantly reduced and mitochondrial ROS was increased in RUPP versus normal pregnant mitochondria. Mean arterial pressure was elevated in RUPP (n=6) compared with normal pregnant rats (n=5; 126±4 versus 103±4 mm Hg; P<0.05) and treatment with mitochondrial-specific antioxidants (MitoQ/MitoTEMPO) significantly reduced mean arterial pressure in RUPPs (n=5-10). Mitochondrial ROS was significantly elevated in endothelial cells incubated with RUPP serum compared from with normal pregnant rats, whereas serum from mito antioxidant-treated RUPP rats attenuated this response. Impaired mitochondrial function and vascular, placental, and renal mitochondrial ROS play an important role in hypertension and reduced fetal weight in response to placental ischemia during pregnancy.

Mitochondrial dysfunction plays an important role in obesity-induced cardiac impairment. SIRT3 is a mitochondrial protein associated with increased human life span and metabolism. This study investigated the functional role of SIRT3 in obesity-induced cardiac dysfunction. Wild-type (WT) and SIRT3 knockout (KO) mice were fed a normal diet (ND) or high-fat diet (HFD) for 16 weeks. Body weight, fasting glucose levels, reactive oxygen species (ROS) levels, myocardial capillary density, cardiac function and expression of hypoxia-inducible factor (HIF)-1α/-2α were assessed. HFD resulted in a significant reduction in SIRT3 expression in the heart. Both HFD and SIRT3 KO mice showed increased ROS formation, impaired HIF signalling and reduced capillary density in the heart. HFD induced cardiac hypertrophy and impaired cardiac function. SIRT3 KO mice fed HFD showed greater ROS production and a further reduction in cardiac function compared to SIRT3 KO mice on ND. Thus, the adverse effects of HFD on cardiac function were not attributable to SIRT3 loss alone. However, HFD did not further reduce capillary density in SIRT3 KO hearts, implicating SIRT3 loss in HFD-induced capillary rarefaction. Our study demonstrates the importance of SIRT3 in preserving heart function and capillary density in the setting of obesity. Thus, SIRT3 may be a potential therapeutic target for obesity-induced heart failure.

Women with preeclampsia produce AT1-AA (agonistic autoantibodies to the angiotensin II type 1 receptor), which stimulate reactive oxygen species, inflammatory factors, and hypertensive mechanisms (ET [endothelin] and sFlt-1 [soluble fms-like tyrosine kinase-1]) in rodent models of preeclampsia. The placental ischemic reduced uterine perfusion pressure (RUPP) rat model of preeclampsia exhibits many of these features. In this study, we examined the maternal outcomes of AT1-AA inhibition ('n7AAc') in RUPP rats. Blood pressure was higher in RUPP rats versus normal pregnant (NP) rats (123±2 versus 99±2 mm Hg, <0.05), which was reduced in RUPP+'n7AAc' (105±3 versus 123±2 mm Hg, <0.05 versus RUPP). Uterine artery resistant index was increased in RUPP versus NP rats (0.71±0.02 versus 0.49±0.02, <0.05) and normalized in RUPP+'n7AAc' rats (0.55±0.03). Antiangiogenic factor sFlt-1 was elevated in RUPP versus NP rats (176±37 versus 77±15 pg/mL, <0.05) but normalized in RUPP+'n7AAc' (86±9, =0.05 versus RUPP). Plasma nitrate and nitrite were decreased (14±1 versus 20±1 µMNO, <0.05) and isoprostanes were elevated (20 117±6304 versus 2809±1375 pg/mL, <0.05) in RUPP versus NP rats; and normalized in RUPP+'n7AAc' rats; (18±2 µMNO; 4311±1 pg/mL). PPET-1 (preproendothelin-1) expression increased 4-fold in RUPP versus NP rats which were prevented with 'n7AAc'. Importantly, placental cytolytic natural killer cells were elevated in RUPP versus NP rats (8±2% versus 2±2% gated, <0.05), which was prevented in RUPP+'n7AAc' total (3±1% gated, <0.05) In conclusion, AT1-AA inhibition prevents the rise in maternal blood pressure and several pathophysiological factors associated with preeclampsia in RUPP rats and could be a potential therapy for preeclampsia.

Women with preeclampsia (PE) have increased mean arterial pressure (MAP), natural killer (NK) cells, reactive oxygen species (ROS), and agonistic autoantibodies to the angiotensin II type 1 receptor (AT1-AA). AT1-AA’s administered to pregnant rodents produces a well-accepted model of PE. However, the role of NK cells and mitochondrial reactive oxygen species (mtROS) in AT1-AA mediated hypertension during pregnancy is unknown. We hypothesize that AT1-AA induced model of PE will exhibit elevated MAP, NK cells, and mtROS; while inhibition of the AT1-AA binding to the AT1R would be preventative. Pregnant rats were divided into 4 groups: normal pregnant (NP) (n = 5), NP + AT1-AA inhibitory peptide (NP +‘n7AAc’) (n = 3), NP + AT1-AA infused (NP + AT1-AA) (n = 10), and NP + AT1-AA +‘n7AAc’ (n = 8). Day 13, rats were surgically implanted with mini-pumps infusing either AT1-AA or AT1-AA +‘n7AAc’. Day 19, tissue and blood was collected. MAP was elevated in AT1-AA vs. NP (119 ± 1 vs. 102 ± 2 mmHg, p < 0.05) and this was prevented by ‘n7AAc’ (108 ± 3). There was a 6 fold increase in renal activated NK cells in AT1-AA vs NP (1.2 ± 0.4 vs. 0.2 ± 0.1% Gated, p = 0.05) which returned to NP levels in AT1-AA +‘n7AAc’ (0.1 ± 0.1% Gated). Renal mtROS (317 ± 49 vs. 101 ± 13% Fold, p < 0.05) was elevated with AT1-AA vs NP and was decreased in AT1-AA +‘n7AAc’ (128 ± 16, p < 0.05). In conclusion, AT1-AA’s increased MAP, NK cells, and mtROS which were attenuated by AT1-AA inhibition, thus highlighting new mechanisms of AT1-AA and the importance of drug therapy targeted to AT1-AAs in hypertensive pregnancies.

Preeclampsia (PE) is characterized by new-onset hypertension that usually occurs in the third trimester of pregnancy and is associated with oxidative stress and angiotensin II type 1 receptor agonistic autoantibodies (AT1-AAs). Inhibition of the AT1-AAs in the reduced uterine perfusion pressure (RUPP) rat, a model of PE, attenuates hypertension and many other characteristics of PE. We have previously shown that mitochondrial oxidative stress (mtROS) is a newly described PE characteristic exhibited by the RUPP rat that contributes to hypertension. However, the factors that cause mtROS in PE or RUPP are unknown. Thus, the objective of the current study is to use pharmacologic inhibition of AT1-AAs to examine their role in mtROS in the RUPP rat model of PE. AT1-AA inhibition in RUPP rats was achieved by administration of an epitope-binding peptide (′n7AAc′). Female Sprague-Dawley rats were divided into the following two groups: RUPP and RUPP + AT1-AA inhibition (RUPP + ′n7AAc′). On day 14 of gestation (GD), RUPP surgery was performed; ′n7AAc′ peptide (2 µg/μL) was administered by miniosmotic pumps in a subset of RUPP rats; and on GD19, sera, placentas, and kidneys were collected. mitochondrial respiration and mtROS were measured in isolated mitochondria using the Oxygraph 2K and fluorescent microplate reader, respectively. Placental and renal mitochondrial respiration and mtROS were improved in RUPP + ′n7AAc′ rats compared with RUPP controls. Moreover, endothelial cells (human umbilical vein endothelial cells) treated with RUPP + ′n7AAc′ sera exhibited less mtROS compared with those treated with RUPP sera. Overall, our findings suggest that AT1-AA signaling is one stimulus of mtROS during PE.