Anita Quon

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.

Preeclampsia is a serious pregnancy complication and increases the risk of cardiovascular disease in offspring later in life. Cardiac development includes maturation of cardiomyocytes, a process that is intricately dependent on proper mitochondrial function. However, it remains unclear whether preeclampsia impairs mitochondrial function and alters cardiac maturation of fetal hearts during late gestation. Herein we induced selective reduced uterine placental perfusion (sRUPP), as a model of preeclampsia in rats, to investigate fetal cardiac myosin heavy chain (MYH) expression, reactive oxygen species (ROS) production, mitochondrial respiration, mitochondrial content and dynamics in male and female fetuses at gestational day (GD) 20 (term = GD 22). Litter size was reduced, while pup reabsorptions were increased in sRUPP compared to Sham controls. In only the male fetuses of sRUPP dams, cardiac MYH7/MYH6 ratio was reduced and MYH6 expression increased. Complex IV activity was elevated in sRUPP male fetuses, with no changes in mitochondrial citrate synthase or ATP synthase activities in either sex. However, ROS production increased in only sRUPP female fetuses. In male fetal hearts, sRUPP increased fusion protein MFN1 expression, tended to decrease fusion protein OPA1 expression, and decreased fission protein FIS1 expression. In contrast, MFN2 and OPA1 were reduced in sRUPP female fetuses. In conclusion, the sRUPP model of preeclampsia affected cardiac maturation and mitochondrial function in late gestation fetuses in a sex-specific manner. As prenatal strategies are being developed to improve pregnancy outcomes, sex-specific fetal effects should be taken into consideration.

Pregnant women who were exposed to 14-wk aerobic exercise training intervention have increased miR-21-3p levels in plasma accompanied by an attenuation in the increase of burst incidence across pregnancy.

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.

Background: Preeclampsia is a risk factor for the development of later‐life cardiovascular disease. However, the underlying mechanisms are poorly understood. Excessive hypercholesteremia in pregnancy induces a preeclampsia‐like phenotype, but whether this also impacts maternal vascular function later in life has not been fully characterized. Methods and Results: Sprague Dawley rats received a control diet (CD) or a high‐cholesterol (HCD) diet from gestational day 6 to 20, after which maternal vascular function was assessed 3 months postpartum. Exposure to an HCD in pregnancy reduced later‐life endothelium‐dependent vasodilation in carotid arteries (−15.24±3.27%), which was mediated via prostaglandin H synthase 2. There were no differences in vasodilation between CD and HCD postpartum rats in the mesenteric arteries, coronary arteries, or aortas. Vasoconstriction to phenylephrine increased in carotid arteries (61.02±21.48%) and reduced in aortas (−23.24±6.19%) of the HCD postpartum group versus CD dams, without differences in mesenteric and coronary arteries. The increased vasoconstriction in carotid arteries was due to lower nitric oxide modulation of constriction. Moreover, carotid artery myogenic response was reduced (−37.68±10.07%) and stiffness was increased (19.67±6.21%) in the HCD postpartum rats compared with CD along with decreased elastin density (−20.85±4.52%). The impact of the HCD on vascular function did not occur in age‐matched never‐pregnant female rats. Conclusions: Excessive hypercholesterolemia in pregnancy impairs later‐life maternal vascular function in rats with varying impacts across different vascular beds. Understanding mechanisms for pregnancy‐specific excessive hypercholesterolemia provides avenues for targeted intervention strategies to reduce the burden of cardiovascular disease in women who had a complicated pregnancy.

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.

Hypercholesterolemia in pregnancy is a physiological process required for normal fetal development. In contrast, excessive pregnancy-specific hypercholesterolemia increases the risk of complications, such as preeclampsia. However, the underlying mechanisms are unclear. Toll-like receptor 4 (TLR4) is a membrane receptor modulated by high cholesterol levels, leading to endothelial dysfunction; but whether excessive hypercholesterolemia in pregnancy activates TLR4 is not known. We hypothesized that a high cholesterol diet (HCD) during pregnancy increases TLR4 activity in uterine arteries, leading to uterine artery dysfunction. Sprague Dawley rats were fed a control diet (n=12) or HCD (n=12) during pregnancy (gestational day 6–20). Vascular function was assessed in main uterine arteries using wire myography (vasodilation to methacholine and vasoconstriction to phenylephrine; with and without inhibitors for mechanistic pathways) and pressure myography (biomechanical properties). Exposure to a HCD during pregnancy increased maternal blood pressure, induced proteinuria, and reduced the fetal-to-placental weight ratio for both sexes. Excessive hypercholesterolemia in pregnancy also impaired vasodilation to methacholine in uterine arteries, whereby at higher doses, methacholine caused vasoconstriction instead of vasodilation in only the HCD group, which was prevented by inhibition of TLR4 or prostaglandin H synthase 1. Endothelial nitric oxide synthase expression and nitric oxide levels were reduced in HCD compared with control dams. Vasoconstriction to phenylephrine and biomechanical properties were similar between groups. In summary, excessive hypercholesterolemia in pregnancy impairs uterine artery function, with TLR4 activation as a key mechanism. Thus, TLR4 may be a target for therapy development to prevent adverse perinatal outcomes in complicated pregnancies.

BACKGROUND: Preeclampsia is a complex syndrome that includes maternal vascular dysfunction. Syncytiotrophoblast-derived extracellular vesicles from preeclampsia placentas (preeclampsia-STBEVs) were shown to induce endothelial dysfunction, but an endothelial transmembrane mediator is still unexplored. The LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1) is a transmembrane scavenger receptor that can cause endothelial dysfunction, and its expression is increased in the endothelium of preeclampsia women. In this study, we hypothesized that LOX-1 mediates the effects of preeclampsia-STBEVs on endothelial function. METHODS: Preeclampsia-STBEVs were collected by perfusion of placentas from women with preeclampsia and in vitro and ex vivo endothelial cell function were assessed. RESULTS: In human umbilical vein endothelial cells, inhibition of LOX-1 with LOX-1 blocking antibody (TS20) reduced the uptake of preeclampsia-STBEVs (61.3±8.8%). TS20 prevented the activation of ERK (extracellular signal-regulated kinase, a kinase downstream of LOX-1) and reduced the activation of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells; 21.1±8.0%) and nitrative stress (23.2±10.3%) that was induced by preeclampsia-STBEVs. Vascular function was assessed by wire myography in isolated mesenteric arteries from pregnant rats that were incubated overnight with preeclampsia-STBEVs±TS20. TS20 prevented endothelium-dependent vasodilation impairment induced by preeclampsia-STBEVs. Nitric oxide contribution to the relaxation was reduced by preeclampsia-STBEVs, which was prevented by TS20. Superoxide dismutase or apocynin, an inhibitor of NOX (nicotinamide adenine dinucleotide phosphate oxidase), restored the impaired endothelium-dependent vasodilation in arteries exposed to preeclampsia-STBEVs. CONCLUSIONS: Taken together, our findings demonstrate that LOX-1 mediates the endothelial dysfunction induced by preeclampsia-STBEVs. Our study further expands on the mechanisms that may lead to adverse outcomes in preeclampsia and proposes LOX-1 as a potential target for future interventions.