Murilo Eduardo Graton

Excessive hypercholesterolemia (eHC) in pregnancy is associated with complications such as preeclampsia, yet its impact on maternal cardiac adaptation and long-term cardiovascular health remains unclear. We hypothesized that eHC impairs maternal cardiac structure and function during pregnancy and that these effects persist postpartum. Sprague Dawley rats were fed either a control diet (CTL) or high cholesterol diet (eHC) from gestational day (GD) 6-20 (term=22 days). Echocardiography was performed before pregnancy, at GD20, and 3 months postpartum. Plasma and left ventricular tissue were collected at GD20 and postpartum for molecular analyses. CTL dams demonstrated normal pregnancy-associated cardiac adaptations, including increased diastolic left ventricular internal diameter, stroke volume, cardiac output, and diastolic left ventricular volume in late pregnancy, with normalization postpartum. These adaptations were attenuated in eHC dams. In late pregnancy, eHC dams exhibited reduced stroke volume and cardiac output compared with CTL, along with alterations in diastolic function, including reduced mitral valve A′ velocity. Postpartum, eHC dams showed changes in diastolic indices, including reduced mitral valve A-wave velocity and E′/A′ ratio. Measures of systolic performance (ejection fraction and fractional shortening) were unchanged between groups. Molecular analyses revealed increased cardiomyocyte size, altered collagen remodeling characterized by an increased COL1-to-COL3 ratio, and elevated CD31 expression in eHC dams during pregnancy. Postpartum, collagen remodeling was evident, but now with reduced COL1 and increased COL3 expression. Together, these findings demonstrate that eHC disrupts normal maternal cardiac adaptation during pregnancy and promotes adverse remodeling and cardiac dysfunction postpartum, with potential implications for long-term cardiovascular disease risk.

This study demonstrates that pregnancies complicated by excessive hypercholesterolemia have a higher maternal plasma sFlt-1/PlGF ratio driven by increased sFlt-1 levels, indicating an angiogenic imbalance. Importantly, this imbalance can be prevented with low-dose aspirin, an actionable therapeutic option during pregnancy. Low-dose aspirin suppressed placental inflammation (evidenced by decreased NLRP3 levels) and lowered placental-derived sFlt-1 via sex-specific mechanisms.

Excessive hypercholesterolemia in pregnancy is a risk factor for the development of preeclampsia, but its ensuing impact on offspring cardiovascular health remains not fully understood. In the present study, Sprague Dawley rats were fed a control or high cholesterol diet (HCD) from gestational days 6–20 (term=22 days). Female and male offspring were aged to adulthood (4 months old), and in vivo and ex vivo cardiovascular function were assessed. In female offspring, body weight gain was greater in the HCD group compared with controls after 2 months of age. Blood pressure, echocardiographic parameters, cardiac capacity to recover from an ischemic insult, and endothelium-dependent vasodilation were similar between the female groups. However, vasoconstriction to a thromboxane analog (U46619) was reduced in thoracic aortas, but not in mesenteric, coronary, or carotid arteries, from the HCD females compared with controls, and was associated with lower phosphorylated myosin phosphatase target subunit 1 (MYPT1Thr855) levels. In male offspring, body weight gain, blood pressure, and echocardiographic parameters were similar between the groups, and there was no impact of HCD on vasoconstriction to U46619 or vasodilation in mesenteric arteries, carotid arteries, or thoracic aortas. However, endothelium-dependent vasodilation was reduced in coronary arteries of HCD males compared with controls and was associated with increased reactive oxygen species levels. There was also reduced cardiac capacity of the HCD males to recover from an ischemic insult. In summary, excessive hypercholesterolemia in pregnancy impaired the cardiovascular health of adult female and male offspring, but the mechanisms and vascular beds affected were specific to each sex.

BACKGROUND: Excessive hypercholesterolemia in pregnancy increases the risk of preeclampsia (HC-PE), though the mechanisms remain unclear. We recently showed that uterine artery function is impaired in HC-PE pregnancies via activation of the TLR4 (toll-like receptor 4)/PGHS1 (prostaglandin H synthase 1) pathway. Low-dose aspirin lowers preeclampsia risk in high-risk pregnancies by inhibiting PGHS1, but its effects in HC-PE pregnancies are not known. Moreover, oxidized low-density lipoprotein (oxLDL) levels rise in HC-PE, potentially activating TLR4 and LOX-1 (lectin-like oxLDL receptor-1; scavenger receptor linked to vascular dysfunction in preeclampsia). However, whether this occurs in HC-PE is not known. METHODS: Sprague Dawley rats received a control or high-cholesterol diet (to induce HC-PE) from gestational day 6 to 20, with placebo or low-dose aspirin (1.5 mg/kg daily) given from gestational day 10 to 20. On gestational day 20, pregnancy outcomes and uterine artery function were assessed. RESULTS: Uterine artery blood flow velocity and placental weights were higher in HC-PE placebo-treated dams versus controls, but these were reduced by low-dose aspirin. Endothelium-dependent vasodilation was impaired in the uterine arteries of the HC-PE placebo group versus controls and was corrected by low-dose aspirin. Ex vivo inhibition of TLR4, PGHS1, or LOX-1 also normalized endothelium-dependent vasodilation in the HC-PE placebo-treated dams. Exposure to oxLDL in the bath (modeling a secondary hit) further impaired endothelium-dependent vasodilation in the uterine arteries of the HC-PE placebo group, partially via TLR4 and LOX-1, which was prevented by low-dose aspirin. CONCLUSIONS: Low-dose aspirin improved uterine artery endothelial function in HC-PE pregnancies; likely by suppressing the TLR4/LOX-1/PGHS1 pathway.

Little is known about the (long-lasting) impact of pregnancy complications on offspring carotid artery function. We showed that, in adult male offspring, prenatal hypoxia decreased carotid artery myogenic tone and stiffness and changed collagen and elastin densities, whereas in females, prenatal hypoxia increased stiffness. These findings contribute to understanding sex-specific differences of adult offspring exposed to a suboptimal in utero environment on the carotid arteries, an important/easily accessible vascular bed for patient disease evaluation.

Prenatal hypoxia is associated with placental oxidative stress, leading to impaired fetal growth and an increased risk of cardiovascular disease in the adult offspring; however, the mechanisms are unknown. Alterations in mitochondrial function may result in impaired cardiac function in offspring. In this study, we hypothesized that cardiac mitochondrial function is impaired in adult offspring exposed to intrauterine hypoxia, which can be prevented by placental treatment with a nanoparticle-encapsulated mitochondrial antioxidant (nMitoQ). Cardiac mitochondrial respiration was assessed in 4-month-old rat offspring exposed to prenatal hypoxia (11% O₂) from gestational day (GD)15–21 receiving either saline or nMitoQ on GD 15. Prenatal hypoxia did not alter cardiac mitochondrial oxidative phosphorylation capacity in the male offspring. In females, the NADH + succinate pathway capacity decreased by prenatal hypoxia and tended to be increased by nMitoQ. Prenatal hypoxia also decreased the succinate pathway capacity in females. nMitoQ treatment increased respiratory coupling efficiency in prenatal hypoxia-exposed female offspring. In conclusion, prenatal hypoxia impaired cardiac mitochondrial function in adult female offspring only, which was improved with prenatal nMitoQ treatment. Therefore, treatment strategies targeting placental oxidative stress in prenatal hypoxia may reduce the risk of cardiovascular disease in adult offspring by improving cardiac mitochondrial function in a sex-specific manner.

The uncontrolled production of the reactive oxygen species (ROS) generates oxidative stress and the development of chronic diseases, such as hypertension. Antioxidant enzymes can reduce the cellular level of ROS. Nuclear erythroid factor 2 (Nrf-2) favors the expression and activity of antioxidant enzymes. In hypertensive rats, Nrf-2 expresssion appears to be reduced in blood vessels and, consequently, it favors the oxidative stress and vascular dysfunction. Apocynin (APO) has been considered a new antioxidant drug. APO reduces blood pressure, decreases ROS production, and improves endothelial function in spontaneously hypertensive rats (SHR). We hypothesized that the role of Nrf-2 in vascular reactivity is altered in SHR and APO-treatment prevents this alteration. To test this hypothesis, we evaluated aorta reactivity to phenylephrine (PE) and acetylcholine (ACh), in the absence and presence of Brusatol, Nrf-2 inhibitor. We used aortas from normotensive Wistar rats and SHR, untreated or treated with APO. Brusatol increased the reactivity of the aortas from SHR to PE, but did not change the reactivity of Wistar rat aortas. In APO-treated SHR aortas, the effect of Brusatol was not observed. The vasodilator responses to ACh were not modified by Brusatol in aortas from normotensive or hypertensive rats, untreated or treated with APO. These results suggest that Nrf-2 is activated in the contractile response to PE. In SHR aortas, exacerbated generation of ROS induces the activation of Nrf-2. This suggestion is reinforced by the lack of Brusatol effect in APO-treated SHR aortas. As APO is an antioxidant drug, the reduction of ROS in vascular cells would not lead to Nrf-2 activation.