Decreased endothelium-dependent vascular relaxation during reduction of uterine perfusion pressure in pregnant rat

Distinct phenotypes in the preeclamptic-like mouse model induced by adenovirus carrying sFlt1 and recombinant sFlt1 protein

BACKGROUND

Preeclampsia (PE) is a pregnancy-specific, multisystemic disorder that affects 2-8% pregnancies worldwide and is a leading cause of maternal and perinatal mortality. At present, there is no cure for PE apart from delivery the placenta. Therefore, it is important and urgent to possess a suitable animal model to study the pathology and treatment of PE. When exogenous soluble fms-like tyrosine kinase-1 (sFlt-1) is administered, pregnant animals develop a PE-like phenotype. However, there is no report on the comparison between different methods of constructing PE mouse models using sFlt-1.

METHODS

In this study, the adenovirus carrying sFlt-1(ADV-Flt-1) and recombinant murine sFlt-1 protein (RM Flt-1) are two different methods were used to induce and compare PE-like mouse models. Pregnancy outcomes were examined on E14.5 and E17.5.

RESULTS

Our data showed that on E14.5, the adenovirus carrying sFlt-1 induced PE-like phenotype, whereas recombinant murine sFlt-1 protein not. On E17.5, both the two methods induced PE-like phenotype including hypertension, proteinuria, fetal growth restriction, placental and glomerular endotheliosis. Importantly, in the adenoviral-mediated sFlt-1 group, the circulating concentration of sFlt-1 were higher than in the recombinant sFlt-1 group, leading to earlier and more severe symptoms of PE. The ADV-Flt-1 group is easy to operate, quickly effective and efficient. The RM Flt-1 group is safer and more stable, with good repeatability, but slower to take effect.

CONCLUSIONS

We proposed that the adenoviral-mediated sFlt-1 model can better simulate early-onset and severe PE.

Impaired Endothelium-Dependent Vasodilation and Increased Levels of Soluble Fms-like Tyrosine Kinase-1 Induced by Reduced Uterine Perfusion Pressure in Pregnant Rats: Evidence of Protective Effects with Sodium Nitrite Treatment in Preeclampsia

Preeclampsia (PE) is a hypertensive disorder of pregnancy and is associated with increases in soluble fms-like tyrosine kinase-1 (sFlt-1) and reductions in nitric oxide (NO) levels. Placental ischemia and hypoxia are hypothesized as initial pathophysiological events of PE. Nitrite (NO metabolite) may be recycled back to NO in ischemic and hypoxic tissues. Therefore, this study examined the sodium nitrite effects in an experimental model of PE. Pregnant rats received saline (Preg group) or sodium nitrite (Preg + Na-Nitrite group). Pregnant rats submitted to the placental ischemia received saline (RUPP group) or sodium nitrite (RUPP + Na-Nitrite group). Blood pressure, placental and fetal weights, and the number of pups were recorded. Plasma levels of NO metabolites and sFlt-1 were also determined. Vascular and endothelial functions were also measured. Blood pressure, placental and fetal weights, the number of pups, NO metabolites, sFlt-1 levels, vascular contraction, and endothelium-dependent vasodilation in the RUPP + Na-Nitrite rats were brought to levels comparable to those in Preg rats. In conclusion, sodium nitrite may counteract the reductions in NO and increases in sFlt-1 levels induced by the placental ischemia model of PE, thus suggesting that increased blood pressure and vascular and endothelial dysfunctions may be attenuated by sodium nitrite-derived NO.

Maternal Microvascular Dysfunction During and After Preeclamptic Pregnancy

Preeclampsia, a pregnancy disorder characterized by de novo hypertension and maternal multisystem organ dysfunction, is the leading cause of maternal mortality worldwide and is associated with a fourfold greater risk of cardiovascular disease throughout the lifespan. Current understanding of the etiology of preeclampsia remains unclear, due in part to the varying phenotypical presentations of the disease, which has hindered the development of effective and mechanism-specific treatment or prevention strategies both during and after the affected pregnancy. These maternal sequelae of preeclampsia are symptoms of systemic vascular dysfunction in the maternal nonreproductive microvascular beds that drives the development and progression of adverse cardiovascular outcomes during preeclampsia. Despite normalization of vascular disturbances after delivery, subclinical dysfunction persists in the nonreproductive microvascular beds, contributing to an increased lifetime risk of cardiovascular and metabolic diseases and all-cause mortality. Given that women with a history of preeclampsia demonstrate vascular dysfunction despite an absence of traditional CVD risk factors, an understanding of the underlying mechanisms of microvascular dysfunction during and after preeclampsia is essential to identify potential therapeutic avenues to mitigate or reverse the development of overt disease. This article aims to provide a summary of the existing literature on the pathophysiology of maternal microvascular dysfunction during preeclampsia, the mechanisms underlying the residual dysfunction that remains after delivery, and current and potential treatments both during and after the affected pregnancy that may reduce microvascular dysfunction in these high-risk women. © 2024 American Physiological Society. Compr Physiol 14:5703-5727, 2024.

Increased uterine arterial tone, stiffness and remodeling with augmented matrix metalloproteinase-1 and -7 in uteroplacental ischemia-induced hypertensive pregnancy

Preeclampsia is a pregnancy-related disorder manifested as hypertensive pregnancy (HTN-Preg) and often fetal growth restriction (FGR), but the mechanisms involved are unclear. We have reported enhanced reactivity of systemic vessels in HTN-Preg rats, but the critical changes in the uterine circulation are less clear. We tested whether HTN-Preg involves localized aberrations in uterine arterial tone, stiffness and remodeling by matrix metalloproteinases (MMPs). Blood pressure (BP) and litter size were recorded in normal pregnant (Preg) rats and Preg rats with reduced uteroplacental perfusion pressure (RUPP). Isolated uterine arteries were placed in a pressure myograph for measuring intrinsic and extrinsic tone and arterial stiffness. Arteries were bathed in normal Krebs solution (2.5 mM Ca2+), Ca2+-free (2 mM EGTA) Krebs, treated with sodium nitroprusside (SNP), or endothelium denuded, then pressurized at 10 mmHg steps from 10 to 110 mmHg, and the % change in diameter was analyzed to measure total (active + passive), active Ca2+-dependent myogenic, passive, and endothelium-dependent tone, respectively. BP was higher and the litter size and pup weight were reduced in RUPP vs Preg rats. In normal Krebs, increasing intraluminal pressure caused smaller increments in diameter in arteries of RUPP vs Preg rats, suggesting greater total vascular tone. Arterial incubation in Ca2+-free Krebs, treatment with SNP or endothelium-removal abolished the differences in vascular tone, and subtraction of each of these components from total vascular tone revealed significant active Ca2+-dependent myogenic, passive, and endothelium-dependent tone, respectively, in RUPP vs Preg rats. The total and passive strain-stress curves were shifted leftward in arteries of RUPP vs Preg rats, indicating increased uterine arterial stiffness. Arterial sections showed decreased lumen/total and increased wall/total area, and immunohistochemistry revealed greater MMP-1 and MMP-7 staining particularly in the media, suggesting uterine arterial remodeling by MMPs in RUPP vs Preg rats. The increased uterine arterial active myogenic, passive, and endothelium-dependent tone, arterial stiffness and remodeling by MMPs would further reduce uterine blood flow and exacerbate uteroplacental ischemia, FGR and HTN-Preg.

Guidelines for assessing maternal cardiovascular physiology during pregnancy and postpartum

Maternal mortality rates are at an all-time high across the world and are set to increase in subsequent years. Cardiovascular disease is the leading cause of death during pregnancy and postpartum, especially in the United States. Therefore, understanding the physiological changes in the cardiovascular system during normal pregnancy is necessary to understand disease-related pathology. Significant systemic and cardiovascular physiological changes occur during pregnancy that are essential for supporting the maternal-fetal dyad. The physiological impact of pregnancy on the cardiovascular system has been examined in both experimental animal models and in humans. However, there is a continued need in this field of study to provide increased rigor and reproducibility. Therefore, these guidelines aim to provide information regarding best practices and recommendations to accurately and rigorously measure cardiovascular physiology during normal and cardiovascular disease-complicated pregnancies in human and animal models.

Both endothelial mineralocorticoid receptor expression and hyperleptinemia are required for clinical characteristics of placental ischemia in mice

One of the initiating events in preeclampsia (PE) is placental ischemia. Rodent models of placental ischemia do not present with vascular endothelial dysfunction, a hallmark of PE. We previously demonstrated a role for leptin in endothelial dysfunction in pregnancy in the absence of placental ischemia. We hypothesized that placental ischemia requires hyperleptinemia and endothelial mineralocorticoid receptor (ECMR) expression to induce PE-associated endothelial dysfunction in pregnant mice. We induced placental ischemia via the reduced uterine perfusion pressure (RUPP) procedure in pregnant ECMR-intact (ECMR+/+) and ECMR deletion (ECMR-/-) mice at gestational day (GD) 13. ECMR+/+ RUPP pregnant mice also received concurrent leptin infusion via miniosmotic pump (0.9 mg/kg/day). RUPP increased blood pressure via radiotelemetry and decreased fetal growth in ECMR+/+ pregnant mice. Both increases in blood pressure and reduced fetal growth were abolished in RUPP ECMR-/- mice. Placental ischemia did not decrease endothelial-dependent relaxation to acetylcholine (ACh) but increased phenylephrine (Phe) contraction in mesenteric arteries of pregnant mice, which was ablated by ECMR deletion. Addition of leptin to RUPP mice significantly reduced ACh relaxation in ECMR+/+ pregnant mice, accompanied by an increase in soluble FMS-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PLGF) ratio. In conclusion, our data indicate that high leptin levels drive endothelial dysfunction in PE and that ECMR is required for clinical characteristics of hypertension and fetal growth restriction in placental ischemia PE. Collectively, we show that both ECMR and leptin play a role to mediate PE.NEW & NOTEWORTHY Leptin is a key feature of preeclampsia that initiates vascular endothelial dysfunction in preeclampsia characterized by placental ischemia. Endothelial mineralocorticoid receptor (ECMR) deletion in placental ischemia protects pregnant mice from elevations in blood pressure and fetal growth restriction in pregnancy. Increases in leptin production mediate the key pathological feature of endothelial dysfunction in preeclampsia in rodents. ECMR activation contributes to the increase in blood pressure and fetal growth restriction in preeclampsia.

Reduced uterine perfusion pressure as a model for preeclampsia and fetal growth restriction in murine: a systematic review and meta-analysis

The reduced uterine perfusion pressure (RUPP) model is frequently used to study preeclampsia and fetal growth restriction. An improved understanding of influential factors might improve reproducibility and reduce animal use considering the variability in RUPP phenotype. We performed a systematic review and meta-analysis by searching Medline and Embase (until 28 March, 2023) for RUPP studies in murine. Primary outcomes included maternal blood pressure (BP) or proteinuria, fetal weight or crown-rump length, fetal reabsorptions, or antiangiogenic factors. We aimed to identify influential factors by meta-regression analysis. We included 155 studies. Our meta-analysis showed that the RUPP procedure results in significantly higher BP (MD = 24.1 mmHg; [22.6; 25.7]; n = 148), proteinuria (SMD = 2.3; [0.9; 3.8]; n = 28), fetal reabsorptions (MD = 50.4%; [45.5; 55.2]; n = 42), circulating soluble FMS-like tyrosine kinase-1 (sFlt-1) (SMD = 2.6; [1.7; 3.4]; n = 34), and lower fetal weight (MD = -0.4 g; [-0.47; -0.34]; n = 113. The heterogeneity (variability between studies) in primary outcomes appeared ≥90%. Our meta-regression identified influential factors in the method and time point of BP measurement, randomization in fetal weight, and type of control group in sFlt-1. The RUPP is a robust model considering the evident differences in maternal and fetal outcomes. The high heterogeneity reflects the observed variability in phenotype. Because of underreporting, we observed reporting bias and a high risk of bias. We recommend standardizing study design by optimal time point and method chosen for readout measures to limit the variability. This contributes to improved reproducibility and thereby eventually improves the translational value of the RUPP model.

Thrombopoietin exerts a neuroprotective effect by inhibiting the suppression of neuronal proliferation and axonal outgrowth in intrauterine growth restriction rats

Chronic hypoxia in utero causes intrauterine growth restriction (IUGR) of the fetus. IUGR infants are known to be at higher risk for neurodevelopmental disorders, but the mechanism is unclear. In this study, we analyzed the structure of the cerebral cortex using IUGR model rats generated through a reduced uterine perfusion pressure operation. IUGR rats exhibited thinner cerebral white matter and enlarged lateral ventricles compared with control rats. Expression of neuron cell markers, Satb2, microtubule-associated protein (MAP)-2, α-tubulin, and nestin was reduced in IUGR rats, indicating that neurons were diminished at various developmental stages in IUGR rats, from neural stem cells to mature neurons. However, there was no increase in apoptosis in IUGR rats. Cells positive for Ki67, a marker of cell proliferation, were reduced in neurons and all glial cells of IUGR rats. In primary neuron cultures, axonal elongation was impaired under hypoxic culture conditions mimicking the intrauterine environment of IUGR infants. Thus, in IUGR rats, chronic hypoxia in utero suppresses the proliferation of neurons and glial cells as well as axonal elongation, resulting in cortical thinning and enlarged lateral ventricles. Thrombopoietin (TPO), a platelet growth factor, inhibited the decrease in neuron number and promoted axon elongation in primary neurons under hypoxic conditions. Intraperitoneal administration of TPO to IUGR rats resulted in increases in the number of NeuN-positive cells and the area coverage of Satb2. In conclusion, suppression of neuronal proliferation and axonal outgrowth in IUGR rats resulted in cortical thinning and enlargement of lateral ventricles. TPO administration might be a novel therapeutic strategy for treating brain dysmaturation in IUGR infants.

Mitochondrial-targeted antioxidant attenuates preeclampsia-like phenotypes induced by syncytiotrophoblast-specific Gαq signaling

Syncytiotrophoblast stress is theorized to drive development of preeclampsia, but its molecular causes and consequences remain largely undefined. Multiple hormones implicated in preeclampsia signal via the Gαq cascade, leading to the hypothesis that excess Gαq signaling within the syncytiotrophoblast may contribute. First, we present data supporting increased Gαq signaling and antioxidant responses within villous and syncytiotrophoblast samples of human preeclamptic placenta. Second, Gαq was activated in mouse placenta using Cre-lox and DREADD methodologies. Syncytiotrophoblast-restricted Gαq activation caused hypertension, kidney damage, proteinuria, elevated circulating proinflammatory factors, decreased placental vascularization, diminished spiral artery diameter, and augmented responses to mitochondrial-derived superoxide. Administration of the mitochondrial-targeted antioxidant Mitoquinone attenuated maternal proteinuria, lowered circulating inflammatory and anti-angiogenic mediators, and maintained placental vascularization. These data demonstrate a causal relationship between syncytiotrophoblast stress and the development of preeclampsia and identify elevated Gαq signaling and mitochondrial reactive oxygen species as a cause of this stress.

Pregnancy hypertension-associated endothelial dysfunction is attenuated by isoflurane anesthesia: Evidence of protective effect related to increases in nitric oxide

AIMS

Pregnancy hypertension-induced endothelial dysfunction associated with impairment of nitric oxide (NO) bioavailability and hemodynamic derangements is a challenging for urgent procedures requiring maternal anesthesia. The volatile anesthetic isoflurane has demonstrated NO-associated protective effects. However, this isoflurane-induced effect is still unclear in pregnancy hypertension. Therefore, the present study examined the potential protective effects of isoflurane anesthesia on endothelial dysfunction and hemodynamic changes induced by hypertensive pregnancy associated with fetal and placental growth restrictions.

MATERIALS AND METHODS

Animals were distributed into four groups: normotensive pregnant rats (Preg), anesthetized pregnant rats (Preg+Iso), hypertensive pregnant rats (HTN-Preg), and anesthetized hypertensive pregnant rats (HTN-Preg+Iso). Systolic and diastolic pressures, mean arterial pressure (MAP), heart rate, fetal and placental weights, vascular contraction, endothelium-derived NO-dependent vasodilation, and NO levels were assessed. The vascular endothelial growth factor (VEGF) levels and endothelial NO synthase (eNOS) Serine (1177) phosphorylation (p-eNOS) expression were also examined.

KEY FINDINGS

Isoflurane produced more expressive hypotensive effects in the HTN-Preg+Iso versus Preg+Iso group, with respective reductions in MAP by 50 ± 13 versus 25 ± 4 mmHg (P < 0.05). Also, HTN-Preg+Iso compared to the HTN-Preg group showed (respectively) preventions against the weight loss of the fetuses (4.0 ± 0.6 versus 2.8 ± 0.6 g, P < 0.05) and placentas (0.37 ± 0.06 versus 0.30 ± 0.06 mg, P < 0.05), hyper-reactive vasocontraction response (1.8 ± 0.4 versus 2.8 ± 0.6 g, P < 0.05), impaired endothelium-derived NO-dependent vasodilation (84 ± 8 versus 50 ± 17 %, P < 0.05), reduced VEGF levels (147 ± 46 versus 25 ± 13 pg/mL, P < 0.05), and decreased p-eNOS expression (0.24 ± 0.07 versus 0.09 ± 0.05 arbitrary units, P < 0.05).

SIGNIFICANCE

Isoflurane anesthesia protects maternal endothelial function in pregnancy hypertension, and possibly endothelium-derived NO is involved.

G-protein-coupled receptor MAS deletion produces a preeclampsia-like phenotype in FVB/N mice

BACKGROUND

An unbalance in the renin-angiotensin (Ang) system (RAS) between the Ang II/AT1 and Ang-(1-7)/Mas axis appears to be involved in preeclampsia (PE), in which a reduction in Ang-(1-7) was observed. Here, we tested whether the reduction in the activity of the Ang-(1-7)/Mas axis could be a contributing factor for the development of PE, using Mas-deficient (Mas-/-) mice.

METHODS AND RESULTS

Cardiovascular parameters were evaluated by telemetry before, during pregnancy and 4 days postpartum in 20-week-old Mas-/- and wild-type (WT) female mice. Mas-/- mice presented reduced arterial blood pressure (BP) at baseline (91.3 ± 0.8 in Mas-/- vs. 94.0 ± 0.9 mmHg in WT, Diastolic, P<0.05). However, after the 13th day of gestation, BP in Mas-/- mice started to increase, time-dependently, and at day 19 of pregnancy, these animals presented a higher BP in comparison with WT group (90.5 ± 0.7 in Mas-/- vs. 80.3 ± 3.5 mmHg in WT, Diastolic D19, P<0.0001). Moreover, pregnant Mas-/- mice presented fetal growth restriction, increase in urinary protein excretion as compared with nonpregnant Mas-/-, oliguria, increase in cytokines, endothelial dysfunction and reduced ACE, AT1R, ACE2, ET-1A, and eNOS placental mRNA, similar to some of the clinical manifestations found in the development of PE.

CONCLUSIONS

These results show that Mas-deletion produces a PE-like state in FVB/N mice.

Sodium Nitrite Attenuates Reduced Activity of Vascular Matrix Metalloproteinase-2 and Vascular Hyper-Reactivity and Increased Systolic Blood Pressure Induced by the Placental Ischemia Model of Preeclampsia in Anesthetized Rats

Preeclampsia is a maternal hypertension disorder associated with vascular dysfunction and fetal and placental growth restrictions. Placental ischemia is suggested as the primary trigger of preeclampsia-associated impairments of both endothelium-derived nitric oxide (NO) and the vascular activity of extracellular matrix metalloproteinase-2 (MMP-2). Reduced uteroplacental perfusion pressure (RUPP) is a placental ischemia model of preeclampsia. Reduction of sodium nitrite to NO may occur during ischemic conditions. However, sodium nitrite effects in the RUPP model of preeclampsia have not yet been investigated. Pregnant rats were divided into four groups: normotensive pregnant rats (Norm-Preg), pregnant rats treated with sodium nitrite (Preg + Nitrite), preeclamptic rats (RUPP), and preeclamptic rats treated with sodium nitrite (RUPP + Nitrite). Maternal blood pressure and fetal and placental parameters were recorded. Vascular function, circulating NO metabolites, and the gelatinolytic activity of vascular MMP-2 were also examined. Sodium nitrite attenuates increased blood pressure, prevents fetal and placental weight loss, counteracts vascular hyper-reactivity, and partially restores NO metabolites and MMP-2 activity. In conclusion, sodium nitrite reduction to NO may occur during RUPP-induced placental ischemia, thereby attenuating increased blood pressure, fetal and placental growth restriction, and vascular hyper-reactivity associated with preeclampsia and possibly restoring NO and MMP-2 activity, which underlie the blood pressure-lowering effects.

VASCULAR AND RENAL MECHANISMS OF PREECLAMPSIA

Preeclampsia (PE) is a multisystem obstetric disorder that affects 2-10% of pregnancies worldwide and it is a leading cause of maternal and fetal morbidity and mortality. The etiology of PE development is not clearly delineated, but since delivery of the fetus and placenta often leads to symptom resolution in the most cases of PE, it is hypothesized that the placenta is the inciting factor of the disease. Current management strategies for PE focus on treating the maternal symptoms to stabilize the mother in an attempt to prolong the pregnancy. However, the efficacy of this management strategy is limited. Therefore, identification of novel therapeutic targets and strategies is needed. Here, we provide a comprehensive overview of the current state of knowledge regarding mechanisms of vascular and renal pathophysiology during PE and discuss potential therapeutic targets directed at improving maternal vascular and renal function.

Growth Restriction in Preeclampsia: Lessons from Animal Models

Preeclampsia remains a major health concern for mother and child. Yet, treatment options remain limited to early delivery. Placental dysfunction in preeclampsia occurs in response to an increase in oxidative stress and inflammatory cytokines with vasoactive and anti-angiogenic factors contributing to impaired maternal and fetal health. Moreover, recent studies indicate a potential role for epigenetic mediators in the pathophysiology of placental ischemia. Numerous animal models are utilized to explore the pathogenesis of preeclampsia and fetal growth restriction. This review provides a brief overview of recent progress in preclinical studies regarding potential therapeutic targets for the treatment and prevention of preeclampsia with an emphasis on fetal growth restriction and the fetal programming of increased cardiovascular risk.

Increased Ca2+-dependent intrinsic tone and arterial stiffness in mesenteric microvessels of hypertensive pregnant rats

Preeclampsia is a pregnancy-related hypertensive disorder (HTN-Preg) with unclear mechanisms. We have shown increased vascular reactivity to extrinsic vasoconstrictors in HTN-Preg rats. Here, we test whether microvascular intrinsic tone and arterial stiffness could contribute to HTN-Preg, and examined the underlying cellular mechanisms. On gestational day 19, BP was recorded in normal pregnant (Preg) rats and Preg rats with reduced uterine perfusion pressure (RUPP), and mesenteric microvessels were mounted on a pressure myograph for measurement of intrinsic tone, simultaneous changes in [Ca2+]i (fura-2 340/380 ratio), and arterial stiffness. Arteries were incubated in Ca2+-containing and 0 Ca2+ (2 mM EGTA) Krebs, pressurized at 10 to 110 mmHg in 10 mmHg increments, and the % change in vessel diameter from initial diameter at 10 mmHg was analyzed for measurement of total (active + passive) intrinsic tone and passive intrinsic response, respectively. The passive response was then subtracted from the total intrinsic tone to determine the active myogenic tone. The strain-stress relationship was also constructed as a measure of arterial stiffness. BP was higher in RUPP vs Preg rats. In Ca2+-containing Krebs, increases in intraluminal pressure caused smaller increases in diameter and greater increases in [Ca2+]i in microvessels of RUPP vs Preg rats, suggesting increased Ca2+-dependent myogenic tone. In 0 Ca2+ Krebs, increases in pressure also caused less increases in diameter in microvessels of RUPP vs Preg rats, but with no changes in [Ca2+]i, suggesting changes in the structure and mechanics of the arterial wall. The total and passive strain-stress relationship was shifted to the left in microvessels of RUPP vs Preg rats, suggesting increased arterial wall stiffness. Histology and immunohistochemistry showed greater vascular wall thickness and collagen-I staining in RUPP vs Preg rats, supporting changes in the wall architecture and structural proteins. The increased active myogenic tone and underlying increases in Ca2+ signaling as well as the increased passive intrinsic response, arterial stiffness and collagen-I in the mesenteric microvessels could play a role in the regulation of blood flow to the splanchnic region and the increased vascular resistance and BP in HTN-Preg.

Evidence of Nitric Oxide Impairment During Hypertensive Pregnancies

Hypertensive disorders of pregnancy complicate up to 10% of pregnancies worldwide, and they can be classified into (1) gestational hypertension, (2) preeclampsia, (3) chronic hypertension and (4) chronic hypertension with preeclampsia. Nitric oxide (NO) plays an essential role in the haemodynamic adaptations observed during pregnancy. It has been shown that the nitric oxide pathway's dysfunction during pregnancy is associated with placental- and vascular-related diseases such as hypertensive disorders of pregnancy. This review aims to present a brief definition of hypertensive disorders of pregnancy and physiological maternal cardiovascular adaptations during pregnancy. We also detail how NO signalling is altered in the (a) systemic vasculature, (b) uterine artery/spiral arteries, (c) implantation and (d) placenta of hypertensive disorders during pregnancy. We conclude by summarizing the anti-hypertensive therapy of hypertensive disorders of pregnancy as a specific management strategy.

Serum Collected from Preeclamptic Pregnancies Drives Vasoconstriction of Human Omental Arteries-A Novel Ex Vivo Model of Preeclampsia for Therapeutic Development

New-onset maternal hypertension is a hallmark of preeclampsia, driven by widespread endothelial dysfunction and systemic vasoconstriction. Here, we set out to create a new ex vivo model using preeclamptic serum to cause injury to the endothelium, mimicking vascular dysfunction in preeclampsia and offering the potential to evaluate candidate therapeutic interventions. Human omental arteries were collected at caesarean section from normotensive pregnant patients at term (n = 9). Serum was collected from pregnancies complicated by preterm preeclampsia (birth < 34 weeks’ gestation, n = 16), term preeclampsia (birth > 37 weeks’ gestation, n = 5), and healthy gestation-matched controls (preterm n = 16, term n = 12). Using wire myography, we performed ex vivo whole vessel assessment where human omental arteries were treated with increasing doses of each serum treatment (2−20%) and vasoreactivity was assessed. All pregnant serum treatments successfully drove vasoconstriction; no significant difference was observed in the degree of vasoconstriction when exposed to preeclamptic or control serum. We further demonstrated the ability of esomeprazole (a candidate therapeutic for preeclampsia; 0.1−100 µM) to drive vasorelaxation of pre-constricted vessels (only with serum from preeclamptic patients). In summary, we describe a novel human physiological model of preeclamptic vascular constriction. We demonstrate its exciting potential to screen drugs for their therapeutic potential as treatment for vasoconstriction induced by preeclampsia.

Diagnostic biomolecules and combination therapy for pre-eclampsia

Pre-eclampsia (PE), associated with placental malperfusion, is the primary reason for maternal and perinatal mortality and morbidity that can cause vascular endothelial injury and multi-organ injury. Despite considerable research efforts, no pharmaceutical has been shown to stop disease progression. If women precisely diagnosed with PE can achieve treatment at early gestation, the maternal and fetal outcomes can be maximally optimized by expectant management. Current diagnostic approaches applying maternal characteristics or biophysical markers, including blood test, urine analysis and biophysical profile, possess limitations in the precise diagnosis of PE. Biochemical factor research associated with PE development has generated ambitious diagnostic targets based on PE pathogenesis and dissecting molecular phenotypes. This review focuses on current developments in biochemical prediction of PE and the corresponding interventions to ameliorate disease progression, aiming to provide references for clinical diagnoses and treatments.

Androgens and Non-Genomic vascular responses in hypertension

Arterial hypertension is a global public health concern. In the last few years, the interest in androgen deficiency has been growing, and the association between androgens and high blood pressure (BP) is still controversial. One purpose of this review was to summarize the available findings in order to clarify whether male sex steroid hormones have beneficial or harmful effect on BP. The second purpose was to enhance the recognition of the acute non-genomic sex-independent vasorelaxing effect of androgens. Remarkably, BP variation is expected to be a consequence of the androgen-induced vasorelaxation which reduces systemic BP; hence the in vivo vasodepressor, hypotensive, and antihypertensive responses of androgens were also analyzed. This article reviews the current understanding of the physiological regulation of vascular smooth muscle contractility by androgens. Additionally, it summarizes older and more recent data on androgens, and some of the possible underlying mechanisms of relaxation, structural-functional differences in the androgen molecules, and their designing ability to induce vasorelaxation. The clinical relevance of these findings in terms of designing future therapeutics mainly the 5-reduced metabolite of testosterone, 5β-dihydrotestosterone, is also highlighted. Literature collected through a PubMed database search, as well as our experimental work, was used for the present review.

Animal Models of Preeclampsia: Mechanistic Insights and Promising Therapeutics

Preeclampsia (PE) is a common pregnancy-specific disorder that is a major cause of both maternal and fetal morbidity and mortality. Central to the pathogenesis of PE is the production of antiangiogenic and inflammatory factors by the hypoxic placenta, leading to the downstream manifestations of the disease, including hypertension and end-organ damage. Currently, effective treatments are limited for PE; however, the development of preclinical animal models has helped in the development and evaluation of new therapeutics. In this review, we will summarize some of the more commonly used models of PE and highlight their similarities to the human syndrome, as well as the therapeutics tested in each model.

Is there a role of proinflammatory cytokines on degenerin-mediated cerebrovascular function in preeclampsia?

Preeclampsia (PE) is associated with adverse cerebrovascular effects during and following parturition including stroke, small vessel disease, and vascular dementia. A potential contributing factor to the cerebrovascular dysfunction is the loss of cerebral blood flow (CBF) autoregulation. Autoregulation is the maintenance of CBF to meet local demands with changes in perfusion pressure. When perfusion pressure rises, vasoconstriction of cerebral arteries and arterioles maintains flow and prevents the transfer of higher systemic pressure to downstream microvasculature. In the face of concurrent hypertension, loss of autoregulatory control exposes small delicate microvessels to injury from elevated systemic blood pressure. While placental ischemia is considered the initiating event in the preeclamptic cascade, the factor(s) mediating cerebrovascular dysfunction are poorly understood. Elevated plasma proinflammatory cytokines, such as tumor necrosis factor α (TNF-α) and interleukin-17 (IL-17), are potential mediators of autoregulatory loss. Impaired CBF responses to increases in systemic pressure are attributed to the impaired pressure-induced (myogenic) constriction of small cerebral arteries and arterioles in PE. Myogenic vasoconstriction is initiated by pressure-induced vascular smooth muscle cell (VSMC) stretch. Recent studies from our laboratory group indicate that proinflammatory cytokines impair the myogenic mechanism of CBF autoregulation via inhibition of vascular degenerin proteins, putative mediators of myogenic constriction in VSMCs. This brief review links studies showing the effect of proinflammatory cytokines on degenerin expression and CBF autoregulation to the pathological cerebral consequences of preeclampsia.

Photoacoustic imaging provides an in vivo assessment of the preeclamptic placenta remodeling and function in response to therapy

INTRODUCTION

There is a lack of effective therapeutic interventions for preeclampsia. A central factor in the etiology of the disease is the development of placental hypoxia due to abnormal vascular remodeling. However, methods to assess the impact of potential therapies on placental growth and remodeling are currently lacking. Here, we develop and validate ultrasound-guided photoacoustic imaging methods to monitor the placental response to therapeutic intervention. Establishing non-invasive tools to image placental function opens up previously unachievable understandings of placental therapeutic response.

METHODS

Studies were performed in the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia. Preclinical research has identified tempol, a superoxide dismutase mimetic, and the phosphodiesterase inhibitor sildenafil as potential therapeutics for preeclampsia, as both improve in vivo maternal outcomes. PA images of the placental environment were acquired in RUPP rats receiving tempol (n = 8) or sildenafil (n = 8) to assess the longitudinal effects of treatment on placental oxygenation and vascular remodeling. Imaging measurements were validated with ex vivo histological analysis.

RESULTS

Spectral photoacoustic imaging non-invasively measured placental hypoxia and impaired vascular growth two days after the RUPP procedure was implemented. Sildenafil significantly improved (p < 0.05) placental oxygenation and promoted vascular remodeling in RUPP animals, while RUPP animals treated with tempol had a diminished placental therapeutic response.

DISCUSSION

We demonstrate that photoacoustic imaging provides in vivo measures of placental oxygenation and vascular remodeling, a previously unobtainable assessment of preeclamptic therapeutic response. These imaging tools have tremendous potential to accelerate the search for effective therapies for preeclampsia.

An Overview of Obesity, Cholesterol, and Systemic Inflammation in Preeclampsia

Preeclampsia (PE), an inflammatory state during pregnancy, is a significant cause of maternal and fetal morbidity and mortality. Adverse outcomes associated with PE include hypertension, proteinuria, uterine/placental abnormalities, fetal growth restriction, and pre-term birth. Women with obesity have an increased risk of developing PE likely due to impaired placental development from altered metabolic homeostasis. Inflammatory cytokines from maternal adipose tissue and circulating cholesterol have been linked to systemic inflammation, hypertension, and other adverse outcomes associated with PE. This review will summarize the current knowledge on the role of nutrients, obesity, and cholesterol signaling in PE with an emphasis on findings from preclinical models.

Impact of reduced uterine perfusion pressure model of preeclampsia on metabolism of placenta, maternal and fetal hearts

Preeclampsia is a cardiovascular pregnancy complication characterised by new onset hypertension and organ damage or intrauterine growth restriction. It is one of the leading causes of maternal and fetal mortality in pregnancy globally. Short of pre-term delivery of the fetus and placenta, treatment options are limited. Consequently, preeclampsia leads to increased cardiovascular disease risk in both mothers and offspring later in life. Here we aim to examine the impact of the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia on the maternal cardiovascular system, placental and fetal heart metabolism. The surgical RUPP model was induced in pregnant rats by applying silver clips around the aorta and uterine arteries on gestational day 14, resulting in ~ 40% uterine blood flow reduction. The experiment was terminated on gestational day 19 and metabolomic profile of placentae, maternal and fetal hearts analysed using high-resolution ¹H NMR spectroscopy. Impairment of uterine perfusion in RUPP rats caused placental and cardiac hypoxia and a series of metabolic adaptations: altered energetics, carbohydrate, lipid and amino acid metabolism of placentae and maternal hearts. Comparatively, the fetal metabolic phenotype was mildly affected. Nevertheless, long-term effects of these changes in both mothers and the offspring should be investigated further in the future.

HOXA9-induced chemerin signals through CMKLR1/AMPK/TXNIP/NLRP3 pathway to induce pyroptosis of trophoblasts and aggravate preeclampsia

BACKGROUND

Up-regulated chemerin correlates with the risk and the severity of preeclampsia. In this study, we examined impacts and underlying mechanisms by which chemerin regulates pyroptosis and trophoblast inflammation.

METHODS

An in vivo preeclampsia model was established in rats and trophoblasts challenged with hypoxia/reoxygenation (H/R) with or without exogenous chemerin were used as the in vitro model. Expressions of homeobox A9 (HOXA9), chemerin, chemerin receptor (the chemokine-like receptor 1 (CMKLR1)), activated AMP-activated protein kinase (AMPK), thioredoxin-interacting protein (TXNIP), and markers related to NOD-like receptor pyrin-containing receptor 3 (NLRP3) inflammasome were examined by Western blot, and in response to AMPK inhibitor, targeting CMKLR1 or HOXA9. Cell viability and death were examined by CCK-8 and Hoechst staining, respectively. Productions of IL-1β and IL-18 in serum or culture medium were measured by ELISA. Transcriptional regulation of HOXA9 on chemerin was examined by combining expressional analysis, chromatin immunoprecipitation, and luciferase reporter assays.

RESULTS

Up-regulations of HOXA9, chemerin, CMKLR1, TXNIP, and NLRP3 inflammasome were observed in both in vivo and in vitro models of preeclampsia, which were associated with increased death of trophoblasts and productions of IL-1β and IL-18. CMKLR1 and activated-AMPK essentially mediated chemerin effects in trophoblasts. HOXA9 directly activated the transcription of chemerin.

CONCLUSIONS

HOXA9 directly activates the transcription of chemerin, which, by activating the AMPK/TXNIP/NLRP3 inflammasome, promotes pyroptosis and inflammation of trophoblasts, and contributes to preeclampsia. Therefore, targeting chemerin signaling may benefit the prevention and/or treatment of preeclampsia.

Physiological characterization of an arginine vasopressin rat model of preeclampsia

Rodent models have contributed greatly to our understanding of preeclampsia (PE) progression in humans, however to-date no model has been able to effectively replicate the clinical presentation of the disease. This study aimed to provide a thorough physiological characterization of the arginine vasopressin (AVP)-induced rat model of PE to determine its applicability in studying the pathophysiology of PE. Female Sprague Dawley rats (n = 24) were separated into four groups (n = 6 per group) viz., pregnant AVP, pregnant saline, non-pregnant AVP, and non-pregnant saline. All animals received a continuous dose of either AVP (150 ng/h) or saline via subcutaneous mini osmotic pumps for 18 days. Full physiological characterization of the model included measuring systolic and diastolic blood pressure, and collecting urine and blood samples for biochemical analysis. AVP infusion significantly increased blood pressure and urinary protein levels in the pregnant rats (p < 0.05). Biochemical markers measured, differed significantly in the AVP-treated vs the pregnant saline groups (p < 0.05). Placental and individual pup weight decreased significantly in the pregnant AVP vs pregnant saline group (p < 0.05). The physiological and hematological data confirm the usefulness of this rat model in the study of PE, since AVP-induced vasoconstriction increases peripheral resistance and successfully mimics the pathological changes associated with PE development in humans.Abbreviations: PE: preeclampsia; AVP: arginine vasopressin; ISSHP: International Society for the Study of Hypertension in Pregnancy; ACOG: American College of Obstetricians and Gynecologists; RUPP: reduced uterine perfusion pressure; sFlt-1: soluble fms-like tyrosine kinase; VEGF: vascular endothelial growth factor; PlGF: placental growth factor; AVP: arginine vasopressin; PAVP: pregnant AVP-treated; PS: pregnant saline; GD: gestational day; ALT: alanine transaminase; NAVP: non-pregnant AVP-treated; NS: non-pregnant saline; AST: aspartate aminotransferase; HDL: high-density lipoprotein; RBC: red blood cell; RAAS: renin-angiotensin aldosterone system; HELLP: hemolysis, elevated liver enzymes, low platelet.

TNFα blockade reverses vascular and uteroplacental matrix metalloproteinases imbalance and collagen accumulation in hypertensive pregnant rats

Preeclampsia is a pregnancy-related disorder of maternal hypertension-in-pregnancy (HTN-Preg) and often fetal growth restriction (FGR). Placental ischemia could be an initiating event leading to inadequate vascular and uteroplacental remodeling and HTN-Preg; however, the molecular targets are unclear. To test the hypothesis that placental ischemia-induced release of proinflammatory cytokines target vascular and uteroplacental matrix metalloproteinases (MMPs), we tested if infusing TNFα (200 ng/kg/day) in day-14 pregnant (Preg) rats causes MMP imbalance and collagen accumulation, and if infusing TNFα decoy receptor Etanercept (0.4 mg/kg/day) in HTN-Preg rats with reduced uteroplacental perfusion pressure (RUPP) reverses MMP imbalance and collagen accumulation. On gestational day-19, blood pressure (BP) was higher in Preg + TNFα and RUPP vs Preg rats, and restored in RUPP + Etanercept rats. Gelatin zymography and Western blots revealed decreases in MMP-2 and MMP-9 and increases in MMP-1 and MMP-7 in aorta, uterus and placenta of Preg + TNFα and RUPP, that were reversed in RUPP + Etanercept rats. Collagen-I and IV were abundant in Preg + TNFα and RUPP, and were decreased in RUPP + Etanercept rats. The litter size, uterine, placenta, and pup weight were markedly reduced in RUPP, insignificantly reduced in Preg + TNFα, and slightly improved in RUPP + Etanercept rats. Thus TNFα blockade reverses the decreases in vascular and uteroplacental MMP-2 and MMP-9, and the increases in MMP-1, MMP-7 and accumulation of collagen-I and IV induced by placental ischemia and TNFα in HTN-Preg rats. Targeting TNFα using cytokine antagonists, or MMPs using MMP modulators could rectify MMP imbalance and collagen accumulation, restore vascular and uteroplacental remodeling, and improve BP in HTN-Preg and preeclampsia.

Endothelium-Derived Hyperpolarizing Factor (EDHF) Mediates Acetylsalicylic Acid (Aspirin) Vasodilation of Pregnant Rat Mesenteric Arteries

Acetylsalicylic acid (aspirin) exhibits a broad range of activities, including analgesic, antipyretic, and antiplatelet properties. Recent clinical studies also recommend aspirin prophylaxis in women with a high risk of pre-eclampsia, a major complication of pregnancy characterized by hypertension. We investigated the effect of aspirin on mesenteric resistance arteries and found outdiscovered the molecular mechanism underlying this action. Aspirin (10⁻¹²–10⁻⁶ M) was tested on pregnant rat mesenteric resistance arteries by a pressurized arteriography. Aspirin was investigated in the presence of several inhibitors of: (a) nitric oxide synthase (L-NAME 2 × 10⁻⁴ M); (b) cyclooxygenase (Indomethacin, 10⁻⁵ M); (c) Ca²⁺-activated K⁺ channels (Kca): small conductance (SKca, Apamin, 10⁻⁷ M), intermediate conductance (IKca, TRAM34, 10⁻⁵ M), and big conductance (BKca, paxilline, 10⁻⁵ M); and (d) endothelial-derived hyperpolarizing factor (high KCl, 80 mM). Aspirin caused a concentration-dependent vasodilation. Aspirin-vasodilation was abolished by removal of endothelium or by high KCl. Furthermore, preincubation with either apamin plus TRAM-34 or paxillin significantly attenuated aspirin vasodilation (p < 0.05). For the first time, we showed that aspirin induced endothelium-dependent vasodilation in mesenteric resistance arteries through the endothelial-derived hyperpolarizing factor (EDHF) and calcium-activated potassium channels. By activating this molecular mechanism, aspirin may lower peripheral vascular resistance and be beneficial in pregnancies complicated by hypertension.

l-Citrulline supplementation during pregnancy improves perinatal and postpartum maternal vascular function in a mouse model of preeclampsia

Preeclampsia is a spontaneously occurring pregnancy complication diagnosed by new-onset hypertension and end-organ dysfunction with or without proteinuria. This pregnancy-specific syndrome contributes to maternal morbidity and mortality and can have detrimental effects on fetal outcomes. Preeclampsia is also linked to increased risk of maternal cardiovascular disease throughout life. Despite intense investigation of this disorder, few treatment options are available. The aim of this study was to investigate the potential therapeutic effects of maternal l-citrulline supplementation on pregnancy-specific vascular dysfunction in the male C57BL/6J × female C57BL/6J C1q-/- preeclampsia-like mouse model. l-Citrulline is a nonessential amino acid that is converted to l-arginine to promote smooth muscle and blood vessel relaxation and improve nitric oxide (NO)-mediated vascular function. To model a preeclampsia-like pregnancy, female C57BL/6J mice were mated to C1q-/- male mice, and a subset of dams was supplemented with l-citrulline throughout pregnancy. Blood pressure, systemic vascular glycocalyx, and ex vivo vascular function were investigated in late pregnancy, and postpartum at 6 and 10 mo of age. Main findings show that l-citrulline reduced blood pressure, increased vascular glycocalyx volume, and rescued ex-vivo vascular function at gestation day 17.5 in this preeclampsia-like model. The vascular benefit of l-citrulline also extended postpartum, with improved vascular function and glycocalyx measures at 6 and 10 mo of age. l-Citrulline-mediated vascular improvements appear, in part, attributable to NO pathway signaling. Taken together, l-citrulline supplementation during pregnancy appears to have beneficial effects on maternal vascular health, which may have translational implications for improved maternal cardiovascular health.

The antithrombin binding regions of heparin mediate fetal growth and reduced placental damage in the RUPP model of preeclampsia†

Preeclampsia is a serious hypertensive disorder of pregnancy, which is only cured with delivery of the placenta, thereby commonly necessitating preterm birth of the fetus. Low-molecular-weight heparin (LMWH) has demonstrated potential to reduce the incidence of preeclampsia in high-risk pregnant women, although the underlying mechanism by which LMWH protects against preeclampsia is unknown. Given the complex structure and biologic actions of heparin, we tested the hypothesis that heparin can mediate preeclampsia prevention via nonanticoagulant pathways. We compared the effects of a nonanticoagulant, glycol-split LMWH (gsHep)—rendered nonanticoagulant through disruption of the antithrombin binding regions—with the LMWH dalteparin in the rat reduced uterine perfusion pressure (RUPP) surgical model of preeclampsia. Although RUPP animals exhibit significantly elevated blood pressure and reduced plasma levels of placental growth factor (PGF) compared to sham, neither dalteparin nor gsHep treatment significantly impacted these parameters. However, the observed positive correlation between PGF levels and number of viable fetuses in RUPP-induced animals suggests that reduced PGF levels were predominately due to placental loss. Daily subcutaneous injections of low-dose dalteparin but not gsHep significantly restored fetal growth that was impaired by RUPP surgery. Placentas from RUPP animals exhibited an abnormal labyrinth structure, characterized by expanded sinusoidal blood spaces, relative to sham-operated animals. Morphometric analysis demonstrated that dalteparin but not gsHep treatment normalized development of the labyrinth in RUPP-exposed conceptuses. These data suggest that the antithrombin-binding regions of LMWH are required to confer its protective effects on fetal growth and placental development.

Chemerin promotes the pathogenesis of preeclampsia by activating CMKLR1/p-Akt/CEBPɑ axis and inducing M1 macrophage polarization

A higher ratio of M1/M2 macrophages and an elevated chemerin level are both related to increased risk of preeclampsia. However, the crosstalk between these two events and their collective contribution to preeclampsia are not well understood. In this study, we assessed the impacts of chemerin chemokine-like receptor 1 (CMKLR1)/p-Akt/CEBPα axis in regulating macrophage polarization and mediating the pathogenic effects of chemerin on preeclampsia. We showed that chemerin, in a dose- and time-dependent manner, stimulated M1 macrophage polarization, inhibited macrophage-induced trophoblast invasion and migration, and suppressed macrophage-mediated angiogenesis. All these chemerin-induced phenotypes are essentially mediated by sequentially CMKLR1, Akt activation, and CEBPα. Mechanistically, CEBPα acted as a transcriptional activator for both IRF8 and chemerin. In vivo, chemerin aggravated preeclampsia, while α-NETA, an inhibitor for CMKLR1, significantly suppressed M1 macrophage polarization and alleviated preeclampsia. In summary, chemerin, by activating CMKLR1/Akt/CEBPα axis, forms a positive feedback loop, promotes M1 macrophage polarization, suppresses trophoblast migration/invasion and angiogenesis, and contributes to preeclampsia. Therefore, targeting chemerin signaling may benefit the prevention and/or treatment of preeclampsia.

Circulating Maternal sFLT1 (Soluble fms-Like Tyrosine Kinase-1) Is Sufficient to Impair Spiral Arterial Remodeling in a Preeclampsia Mouse Model

Supplemental Digital Content is available in the text.

One driving factor for developing preeclampsia—a pregnancy disorder, often associated with poor spiral artery (SpA)-remodeling and fetal growth restriction—is the anti-angiogenic sFLT1 (soluble fms-like tyrosine kinase-1), which is found to be highly upregulated in preeclampsia patients. The sFLT1-mediated endothelial dysfunction is a common theory for the manifestation of maternal preeclampsia symptoms. However, the influence of sFLT1 on SpA-remodeling and the link between placental and maternal preeclampsia symptoms is less understood. To dissect the hsFLT1 (human sFLT1) effects on maternal and/or fetoplacental physiology in preeclampsia, sFLT1-transgenic mice with systemic hsFLT1 overexpression from midgestation onwards were used. SpA-remodeling was analyzed on histological and molecular level in placental/mesometrial triangle tissues. Maternal kidney and aorta morphology was investigated, combined with blood pressure measurements via telemetry. hsFLT1 overexpression resulted in maternal hypertension, aortic wall thickening, and elastin breakdown. Furthermore, maternal kidneys showed glomerular endotheliosis, podocyte damage, and proteinuria. preeclampsia symptoms were combined with fetal growth restriction already at the end of the second trimester and SpA-remodeling was strongly impaired as shown by persisted vascular smooth muscle cells. This phenotype was associated with shallow trophoblast invasion, delayed presence of uterine natural killer cells, and altered lymphatic angiogenesis. Overall, this study showed that circulating maternal hsFLT1 is sufficient to induce typical maternal preeclampsia-like symptoms in mice and impair the SpA-remodeling independent from the fetoplacental compartment, revealing new insights into the interaction between the placental and maternal contribution of preeclampsia.

Rodent models of hypertension

Elevated blood pressure (BP), or hypertension, is the main risk factor for cardiovascular disease. As a multifactorial and systemic disease that involves multiple organs and systems, hypertension remains a challenging disease to study. Models of hypertension are invaluable to support the discovery of the specific genetic, cellular and molecular mechanisms underlying essential hypertension, as well as to test new possible treatments to lower BP. Rodent models have proven to be an invaluable tool for advancing the field. In this review, we discuss the strengths and weaknesses of rodent models of hypertension through a systems approach. We highlight the ways how target organs and systems including the kidneys, vasculature, the sympathetic nervous system (SNS), immune system and the gut microbiota influence BP in each rodent model. We also discuss often overlooked hypertensive conditions such as pulmonary hypertension and hypertensive-pregnancy disorders, providing an important resource for researchers.

Interferon γ neutralization reduces blood pressure, uterine artery resistance index, and placental oxidative stress in placental ischemic rats

Preeclampsia (PE) is characterized by maternal hypertension, intrauterine growth restriction, and increased cytolytic natural killer cells (cNKs), which secrete interferon γ (IFNγ). However, the precise role of IFNγ in contributing to PE pathophysiology remains unclear. Using the reduced uterine perfusion pressure (RUPP) rat model of placental ischemia, we tested the hypothesis that neutralization of IFNγ in RUPPs will decrease placental reactive oxygen species (ROS) and improve vascular function resulting in decreased MAP and improved fetal growth. On gestation day (GD) 14, the RUPP procedure was performed and on GDs 15 and 18, a subset of normal pregnant rats (NP) and RUPP rats were injected with 10 μg/kg of an anti-rat IFNγ monoclonal antibody. On GD 18, uterine artery resistance index (UARI) was measured via Doppler ultrasound and on GD 19, mean arterial pressure (MAP) was measured, animals were euthanized, and blood and tissues were collected for analysis. Increased MAP was observed in RUPP rats compared with NP and was reduced in RUPP + anti-IFNγ. Placental ROS was also increased in RUPP rats compared with NP rats and was normalized in RUPP + anti-IFNγ. Fetal and placental weights were reduced in RUPP rats, but were not improved following anti-IFNγ treatment. However, UARI was elevated in RUPP compared with NP rats and was reduced in RUPP + anti-IFNγ. In conclusion, we observed that IFNγ neutralization reduced MAP, UARI, and placental ROS in RUPP recipients. These data suggest that IFNγ is a potential mechanism by which cNKs contribute to PE pathophysiology and may represent a therapeutic target to improve maternal outcomes in PE.

Placental mitochondrial function as a driver of angiogenesis and placental dysfunction

The placenta is a highly vascularized and complex foetal organ that performs various tasks, crucial to a healthy pregnancy. Its dysfunction leads to complications such as stillbirth, preeclampsia, and intrauterine growth restriction. The specific cause of placental dysfunction remains unknown. Recently, the role of mitochondrial function and mitochondrial adaptations in the context of angiogenesis and placental dysfunction is getting more attention. The required energy for placental remodelling, nutrient transport, hormone synthesis, and the reactive oxygen species leads to oxidative stress, stemming from mitochondria. Mitochondria adapt to environmental changes and have been shown to adjust their oxygen and nutrient use to best support placental angiogenesis and foetal development. Angiogenesis is the process by which blood vessels form and is essential for the delivery of nutrients to the body. This process is regulated by different factors, pro-angiogenic factors and anti-angiogenic factors, such as sFlt-1. Increased circulating sFlt-1 levels have been linked to different preeclamptic phenotypes. One of many effects of increased sFlt-1 levels, is the dysregulation of mitochondrial function. This review covers mitochondrial adaptations during placentation, the importance of the anti-angiogenic factor sFlt-1in placental dysfunction and its role in the dysregulation of mitochondrial function.

Carbonic anhydrase inhibition improves pulmonary artery reactivity and nitric oxide-mediated relaxation in sugen-hypoxia model of pulmonary hypertension

Pulmonary hypertension (PH) is a serious disease with pulmonary arterial fibrotic remodeling and limited responsiveness to vasodilators. Our data suggest that mild acidosis induced by carbonic anhydrase inhibition could ameliorate PH, but the vascular mechanisms are unclear. We tested the hypothesis that carbonic anhydrase inhibition ameliorates PH by improving pulmonary vascular reactivity and relaxation mechanisms. Male Sprague-Dawley rats were either control normoxic (Nx), or injected with Sugen 5416 (20 mg/kg, sc) and subjected to hypoxia (9% O2) (Su + Hx), or Su + Hx treated with acetazolamide (ACTZ, 100 mg/kg/day, in drinking water). After measuring the hemodynamics, right ventricular hypertrophy was assessed by Fulton's Index; vascular function was measured in pulmonary artery, aorta, and mesenteric arteries; and pulmonary arteriolar remodeling was assessed in lung sections. Right ventricular systolic pressure and Fulton's Index were increased in Su + Hx and reduced in Su + Hx + ACTZ rats. Pulmonary artery contraction to KCl and phenylephrine were reduced in Su + Hx and improved in Su + Hx + ACTZ. Acetylcholine (ACh)-induced relaxation and nitrate/nitrite production were reduced in pulmonary artery of Su + Hx and improved in Su + Hx + ACTZ. ACh relaxation was blocked by nitric oxide (NO) synthase and guanylate cyclase inhibitors, supporting a role of NO-cGMP. Sodium nitroprusside (SNP)-induced relaxation was reduced in pulmonary artery of Su + Hx, and ACTZ enhanced relaxation to SNP. Contraction/relaxation were not different in aorta or mesenteric arteries of all groups. Pulmonary arterioles showed wall thickening in Su + Hx that was ameliorated in Su + Hx + ACTZ. Thus, amelioration of pulmonary hemodynamics during carbonic anhydrase inhibition involves improved pulmonary artery reactivity and NO-mediated relaxation and may enhance responsiveness to vasodilator therapies in PH.

Characterisation of cardiac health in the reduced uterine perfusion pressure model and a 3D cardiac spheroid model, of preeclampsia

Background

Preeclampsia is a dangerous cardiovascular disorder of pregnancy that leads to an increased risk of future cardiovascular and metabolic disorders. Much of the pathogenesis and mechanisms involved in cardiac health in preeclampsia are unknown. A novel anti-angiogenic protein, FKBPL, is emerging as having a potential role in both preeclampsia and cardiovascular disease (CVD). Therefore, in this study we aimed to characterise cardiac health and FKBPL regulation in the rat reduced uterine perfusion pressure (RUPP) and a 3D cardiac spheroid model of preeclampsia.

Methods

The RUPP model was induced in pregnant rats and histological analysis performed on the heart, kidney, liver and placenta (n ≥ 6). Picrosirius red staining was performed to quantify collagen I and III deposition in rat hearts, placentae and livers as an indicator of fibrosis. RT-qPCR was used to determine changes in Fkbpl, Icam1, Vcam1, Flt1 and Vegfa mRNA in hearts and/or placentae and ELISA to evaluate cardiac brain natriuretic peptide (BNP45) and FKBPL secretion. Immunofluorescent staining was also conducted to analyse the expression of cardiac FKBPL. Cardiac spheroids were generated using human cardiac fibroblasts and human coronary artery endothelial cells and treated with patient plasma from normotensive controls, early-onset preeclampsia (EOPE) and late-onset preeclampsia (LOPE); n = 3. FKBPL and CD31 expression was quantified by immunofluorescent labelling.

Results

The RUPP procedure induced significant increases in blood pressure (p < 0.001), collagen deposition (p < 0.001) and cardiac BNP45 (p < 0.05). It also induced a significant increase in cardiac FKBPL mRNA (p < 0.05) and protein  expression  (p < 0.01). RUPP placentae also exhibited increased collagen deposition and decreased Flt1 mRNA expression (p < 0.05). RUPP kidneys revealed an increase in average glomerular size (p < 0.05). Cardiac spheroids showed a significant increase in FKBPL expression when treated with LOPE plasma (p < 0.05) and a trend towards increased FKBPL expression following treatment with EOPE plasma (p = 0.06).

Conclusions

The rat RUPP model induced cardiac, renal and placental features reflective of preeclampsia. FKBPL was increased in the hearts of RUPP rats and cardiac spheroids treated with plasma from women with preeclampsia, perhaps reflective of restricted angiogenesis and inflammation in this disorder. Elucidation of these novel FKBPL mechanisms in cardiac health in preeclampsia could be key in preventing future CVD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-021-00376-1.

New views on endothelial dysfunction in gestational hypertension and potential therapy targets

The placenta has vital roles in metabolite exchange, fetal growth, and pre-eclampsia (PE). In this review, we discuss the pathogenesis of hypertension in pregnancy, focusing on four major theories to explain PE, discussing endothelial roles in those theories. We focus in particular on the roles of nitric oxide (NO) and prostacyclin (PGI₂) in placental endothelium, and propose new hypotheses for the influence and mechanisms of endothelial NO and PGI₂ signaling pathways in PE.

Stimulation of soluble guanylate cyclase diminishes intrauterine growth restriction in a rat model of placental ischemia

Placental ischemia in preeclampsia (PE) results in hypertension and intrauterine growth restriction (IUGR). Stimulation of soluble guanylate cyclase (sGC) reduces blood pressure in the clinically relevant reduced uterine perfusion pressure (RUPP) rat model of PE, implicating involvement in RUPP-induced hypertension. However, the contribution of sGC in the development of IUGR in PE is not known. Thus, this study demonstrated the efficacy of Riociguat, an sGC stimulator, in IUGR reversion in the RUPP rat model of PE, and tested the hypothesis that improvement in fetal weight occurs in association with improvement in placental perfusion, placental morphology, and placental nutrient transport protein expression. Sham or RUPP surgery was performed at gestational day 14 (G14) with administration of vehicle (Sham or RUPP) or the sGC stimulator (Riociguat, 10 mg/kg/day sc; sGC-treated) until G20. Fetal weight was reduced (P = 0.004) at G20 in RUPP but not in sGC-treated RUPP compared with Sham, the control group. At G20, uterine artery resistance index (UARI) was increased (P = 0.010) in RUPP, indicating poor placental perfusion; proportional junctional zone surface area was elevated (P = 0.035), indicating impaired placental development. These effects were ameliorated in sGC-treated RUPP. Placental protein expression of nutrient transporter heart fatty acid-binding protein (hFABP) was increased (P = 0.008) in RUPP but not in sGC-treated RUPP, suggesting a compensatory mechanism to maintain normal neurodevelopment. Yet, UARI (P < 0.001), proportional junctional zone surface area (P = 0.013), and placental hFABP protein expression (P = 0.008) were increased in sGC-treated Sham, suggesting a potential adverse effect of Riociguat. Collectively, these results suggest sGC contributes to IUGR in PE.

Unfractionated heparin displaces sFlt-1 from the placental extracellular matrix

Soluble vascular endothelial growth factor receptor-1 (sFlt-1) is an anti-angiogenic protein which is secreted by numerous cell types and acts as a decoy receptor for the angiogenic protein vascular endothelial growth factor (VEGF). Despite its physiologic importance in maintaining angiogenic balance, excess sFlt-1 levels are associated with the pathogenesis of many diseases, especially those with angiogenic imbalance, endothelial dysfunction, and hypertension. Although sFlt-1 is a soluble protein, it contains a binding site for the extracellular matrix component heparan sulfate. This allows cells to retain and localize sFlt-1 in order to prevent excessive VEGF signaling. During pregnancy, placental syncytiotrophoblasts develop a large extracellular matrix which contains significant amounts of heparan sulfate. Consequently, the placenta becomes a potential storage site for large amounts of sFlt-1 bound to extracellular heparan sulfate. Additionally, it should be noted that sFlt-1 can bind to the anticoagulant unfractionated heparin due to its molecular mimicry to heparan sulfate. However, it remains unknown whether unfractionated heparin can compete with heparan sulfate for binding of localized sFlt-1. In this study, we hypothesized that administration of unfractionated heparin would displace and solubilize placental extracellular matrix(ECM)-bound sFlt-1. If unfractionated heparin can displace this large reservoir of sFlt-1 in the placenta and mobilized it into the maternal circulation, we should be able to observe its effects on maternal angiogenic balance and blood pressure. To test this hypothesis, we utilized in vitro, ex vivo, and in vivo methods. Using the BeWo placental trophoblast cell line, we observed increased sFlt-1 in the media of cells treated with unfractionated heparin compared to controls. The increase in media sFlt-1 was found in conjunction with decreased localized cellular Flt (sFlt-1 and Flt-1) as measured by total cell fluorescence. Similar results were observed using ex vivo placental villous explants treated with unfractionated heparin. Real-time quantitative PCR of the explants showed no change in sFlt-1 or heparanase-1 mRNA expression, eliminating increased production and enzymatic cleavage of heparan sulfate as causes for sFlt-1 media increase. Timed-pregnant rats given a continuous infusion of unfractionated heparin exhibited an increased mean arterial pressure as well as decreased bioavailable VEGF compared to vehicle-treated animals. These data demonstrate that chronic unfractionated heparin treatment is able to displace matrix-bound sFlt-1 into the maternal circulation to such a degree that mean arterial pressure is significantly affected. Here we have shown that the placental ECM is a storage site for large quantities of sFlt-1, and that it should be carefully considered in future studies concerning angiogenic balance in pregnancy.

Preeclampsia beyond pregnancy: long-term consequences for mother and child

Preeclampsia is defined as new-onset hypertension after the 20th wk of gestation along with evidence of maternal organ failure. Rates of preeclampsia have steadily increased over the past 30 yr, affecting ∼4% of pregnancies in the United States and causing a high economic burden (22, 69). The pathogenesis is multifactorial, with acknowledged contributions by placental, vascular, renal, and immunological dysfunction. Treatment is limited, commonly using symptomatic management and/or early delivery of the fetus (6). Along with significant peripartum morbidity and mortality, current research continues to demonstrate that the consequences of preeclampsia extend far beyond preterm delivery. It has lasting effects for both mother and child, resulting in increased susceptibility to hypertension and chronic kidney disease (45, 54, 115, 116), yielding lifelong risk to both individuals. This review discusses recent guideline updates and recommendations along with current research on these long-term consequences of preeclampsia.

Paternal deficiency of complement component C1q leads to a preeclampsia-like pregnancy in wild-type female mice and vascular adaptations postpartum

Preeclampsia is a spontaneously occurring, pregnancy-specific syndrome that is clinically diagnosed by new onset hypertension and proteinuria. Epidemiological evidence describes an association between a history of preeclampsia and increased risk for cardiovascular disease in later life; however, the mechanism(s) driving this relationship are unclear. Our study aims to leverage a novel preeclampsia-like mouse model, the C1q^-/- model, to help elucidate the acute and persistent vascular changes during and following a preeclampsia-like pregnancy. Female C57BL/6J mice were mated to C1q^-/- male mice to model a preeclampsia-like pregnancy ("PE-like"), and the maternal cardiovascular phenotype (blood pressure, renal function, systemic glycocalyx, and ex vivo vascular function) was assessed in late pregnancy and postpartum at 6 and 10 mo of age. Uncomplicated, normotensive pregnancies (female C57BL/6J bred to male C57BL/6J mice) served as age-matched controls. In pregnancy, PE-like dams exhibited increased systolic and diastolic pressure during mid- and late gestation, renal dysfunction, fetal growth restriction, and reduced placental efficiency. Ex vivo wire myography studies of mesenteric arteries revealed severe pregnancy-specific endothelial-dependent and -independent vascular dysfunction. At 3 and 7 mo postpartum (6 and 10 mo old, respectively), hypertension resolved in PE-like dams, whereas mild vascular dysfunction persisted at 3 mo postpartum. In conclusion, the female C57BL/6J-by-male C57BL/6J C1q^-/- model recapitulates many aspects of the human preeclampsia syndrome in a low-risk, wild-type female mouse. The pregnancy-specific phenotype results in systemic maternal endothelial-dependent and -independent vascular dysfunction that persists postpartum.

Animal Models of Preeclampsia: Causes, Consequences, and Interventions

Preeclampsia is a common pregnancy complication, affecting 2% to 8% of pregnancies worldwide, and is an important cause of both maternal and fetal morbidity and mortality. Importantly, although aspirin and calcium are able to prevent preeclampsia in some women, there is no cure apart from delivery of the placenta and fetus, often necessitating iatrogenic preterm birth. Preclinical models of preeclampsia are widely used to investigate the causes and consequences of preeclampsia and to evaluate safety and efficacy of potential preventative and therapeutic interventions. In this review, we provide a summary of the published preclinical models of preeclampsia that meet human diagnostic criteria, including the development of maternal hypertension, together with new-onset proteinuria, maternal organ dysfunction, and uteroplacental dysfunction. We then discuss evidence from preclinical models for multiple causal factors of preeclampsia, including those implicated in early-onset and late-onset preeclampsia. Next, we discuss the impact of exposure to a preeclampsia-like environment for later maternal and progeny health. The presence of long-term impairment, particularly cardiovascular outcomes, in mothers and progeny after an experimentally induced preeclampsia-like pregnancy, implies that later onset or reduced severity of preeclampsia will improve later maternal and progeny health. Finally, we summarize published intervention studies in preclinical models and identify gaps in knowledge that we consider should be targets for future research.

Human Placental Vascular Reactivity in Health and Disease: Implications for the Treatment of Pre-eclampsia

Adequate development of the placenta is essential for optimal pregnancy outcome. Pre-eclampsia (PE) is increasingly recognized to be a consequence of placental dysfunction and can cause serious maternal and fetal complications during pregnancy. Furthermore, PE increases the risk of neonatal problems and has been shown to be a risk factor for cardiovascular disease of the mother later in life. Currently, there is no adequate treatment for PE, mainly because its multifactorial pathophysiology remains incompletely understood. It originates in early pregnancy with abnormal placentation and involves a cascade of dysregulated systems in the placental vasculature. To investigate therapeutic strategies it is essential to understand the regulation of vascular reactivity and remodeling of blood vessels in the placenta. Techniques using human tissue such as the ex vivo placental perfusion model provide insight in the vasoactive profile of the placenta, and are essential to study the effects of drugs on the fetal vasculature. This approach highlights the different pathways that are involved in the vascular regulation of the human placenta, changes that occur during PE and the importance of focusing on restoring these dysfunctional systems when studying treatment strategies for PE.

Decreased uterine vascularization and uterine arterial expansive remodeling with reduced matrix metalloproteinase-2 and -9 in hypertensive pregnancy

Normal pregnancy involves extensive remodeling of uterine and spiral arteries and matrix metalloproteinases (MMPs)-mediated proteolysis of extracellular matrix (ECM). Preeclampsia is characterized by hypertension in pregnancy (HTN-Preg) and intrauterine growth restriction (IUGR) with unclear mechanisms. Initial faulty placentation and reduced uterine perfusion pressure (RUPP) could release cytoactive factors and trigger an incessant cycle of suppressed trophoblast invasion of spiral arteries, further RUPP, and progressive placental ischemia leading to HTN-Preg and IUGR; however, the extent and depth of uterine vascularization and the proteolytic enzymes and ECM proteins involved are unclear. We hypothesized that HTN-Preg involves decreased uterine vascularization and arterial remodeling by MMPs and accumulation of ECM collagen. Blood pressure (BP) and fetal parameters were measured in normal Preg rats and RUPP rat model, and the uteri were assessed for vascularity, MMP levels, and collagen deposition. On gestational day 19, BP was higher, and the uterus weight, litter size, and pup weight were reduced in RUPP vs. Preg rats. Histology of uterine tissue sections showed reduced number (5.75 ± 0.95 vs. 11.50 ± 0.87) and size (0.05 ± 0.01 vs. 0.12 ± 0.02 mm2) of uterine spiral arterioles in RUPP vs. Preg rats. Immunohistochemistry showed localization of endothelial cell marker cluster of differentiation 31 (CD31) and smooth muscle marker α-actin in uterine arteriolar wall and confirmed decreased number/size of uterine arterioles in RUPP rats. The cytotrophoblast marker cytokeratin-7 showed less staining and invasion of spiral arteries in the deep decidua of RUPP vs. Preg rats. Uterine arteries showed less expansion in response to increases in intraluminal pressure in RUPP vs. Preg rats. Western blot analysis, gelatin zymography, and immunohistochemistry showed decreases in MMP-2 and MMP-9 and increases in the MMP substrate collagen-IV in uterus and uterine arteries of RUPP vs. those in Preg rats. The results suggest decreased number, size and expansiveness of spiral and uterine arteries with decreased MMP-2 and MMP-9 and increased collagen-IV in HTN-Preg. Decreased uterine vascularization and uterine arterial expansive remodeling by MMPs could be contributing mechanisms to uteroplacental ischemia in HTN-Preg and preeclampsia.NEW & NOTEWORTHY Preeclampsia is a pregnancy-related disorder in which initial inadequate placentation and RUPP cause the release of cytoactive factors and trigger a ceaseless cycle of suppressed trophoblast invasion of spiral arteries, further RUPP, and progressive placental ischemia leading to HTN-Preg and IUGR; however, the extent/depth of uterine vascularization and the driving proteolytic enzymes and ECM proteins are unclear. This study shows decreased number, size, and expansiveness of uterine spiral arteries, with decreased MMP-2 and MMP-9 and increased collagen-IV in HTN-Preg rats. The decreased uterine vascularization and uterine arterial expansive remodeling by MMPs could contribute to progressive uteroplacental ischemia in HTN-Preg and preeclampsia.

Role of B1 and B2 lymphocytes in placental ischemia-induced hypertension

Preeclampsia is a prevalent pregnancy complication characterized by new-onset maternal hypertension and inflammation, with placental ischemia as the initiating event. Studies of others have provided evidence for the importance of lymphocytes in placental ischemia-induced hypertension; however, the contributions of B1 versus B2 lymphocytes are unknown. We hypothesized that peritoneal B1 lymphocytes are important for placental ischemia-induced hypertension. As an initial test of this hypothesis, the effect of anti-CD20 depletion on both B-cell populations was determined in a reduced utero-placental perfusion pressure (RUPP) model of preeclampsia. Anti-murine CD20 monoclonal antibody (5 mg/kg, Clone 5D2) or corresponding mu IgG2a isotype control was administered intraperitoneally to timed pregnant Sprague-Dawley rats on gestation day (GD)10 and 13. RUPP or sham control surgeries were performed on GD14, and mean arterial pressure (MAP) was measured on GD19 from a carotid catheter. As anticipated, RUPP surgery increased MAP and heart rate and decreased mean fetal and placental weight. However, anti-CD20 treatment did not affect these responses. On GD19, B-cell populations were enumerated in the blood, peritoneal cavity, spleen, and placenta with flow cytometry. B1 and B2 cells were not significantly increased following RUPP. Anti-CD20 depleted B1 and B2 cells in peritoneum and circulation but depleted only B2 lymphocytes in spleen and placenta, with no effect on circulating or peritoneal IgM. Overall, these data do not exclude a role for antibodies produced by B cells before depletion but indicate the presence of B lymphocytes in the last trimester of pregnancy is not critical for placental ischemia-induced hypertension.NEW & NOTEWORTHY The adaptive and innate immune systems are implicated in hypertension, including the pregnancy-specific hypertensive condition preeclampsia. However, the mechanism of immune system dysfunction leading to pregnancy-induced hypertension is unresolved. In contrast to previous reports, this study reveals that the presence of classic B2 lymphocytes and peritoneal and circulating B1 lymphocytes is not required for development of hypertension following third trimester placental ischemia in a rat model of pregnancy-induced hypertension.

Characterisation of the Selective Reduced Uteroplacental Perfusion (sRUPP) Model of Preeclampsia

Preeclampsia is a complication of pregnancy characterised by gestational hypertension, proteinuria and/or end organ disease. The reduced uteroplacental perfusion (RUPP) model, via partial occlusion of the lower abdominal aorta, mimics insufficient placental perfusion as a primary causal characteristic of preeclampsia. However, a major limitation of the RUPP model is that perfusion is reduced to the entire hindquarters of the rat resulting in hindlimb ischemia. We hypothesised that clipping the uterine and ovarian arteries in the selective (s)RUPP model would provoke signs of preeclampsia while avoiding systemic ischemia. Sham, RUPP or sRUPP procedures were performed in pregnant Sprague Dawley rats on gestational day (GD)14. On GD21 uterine blood flow was significantly reduced in both the RUPP and sRUPP models while aortic flow was reduced only in RUPP. Both models resulted in increased MAP, increased vascular oxidative stress (superoxide generation), increased pro-inflammatory (RANTES) and reduced pro-angiogenic (endoglin) mediators. Vascular compliance and constriction were unaltered in either RUPP or sRUPP groups. In summary, refinements to the RUPP model simultaneously maintain the characteristic phenotype of preeclampsia and avoid peripheral ischemia; providing a useful tool which may be used to increase our knowledge and bring us closer to a solution for women affected by preeclampsia.

Preeclampsia and intrauterine growth restriction: Role of human umbilical cord mesenchymal stem cells-trophoblast cross-talk

Background

Oxidative stress is involved in the pathogenesis and maintenance of pregnancy-related disorders, such as intrauterine growth restriction (IUGR) and preeclampsia (PE). Human umbilical cord mesenchymal stem cells (hUMSCs) have been suggested as a possible therapeutic tool for the treatment of pregnancy-related disorders in view of their paracrine actions on trophoblast cells.

Objectives

To quantify the plasma markers of peroxidation in patients affected by PE and IUGR and to examine the role of oxidative stress in the pathophysiology of PE and IUGR in vitro by using hUMSCs from physiological and pathological pregnancies and a trophoblast cell line (HTR-8/SVneo).

Study design

In pathological and physiological pregnancies the plasma markers of oxidative stress, arterial blood pressure, serum uric acid, 24h proteinuria, weight gain and body mass index (BMI) were examined. Furthermore, the pulsatility index (PI) of uterine and umbilical arteries, and of fetal middle cerebral artery was measured. In vitro, the different responses of hUMSCs, taken from physiological and pathological pregnancies, and of HTR-8/SVneo to pregnancy-related hormones in terms of viability and nitric oxide (NO) release were investigated. In some experiments, the above measurements were performed on co-cultures between HTR-8/SVneo and hUMSCs.

Results

The results obtained have shown that in pathological pregnancies, body mass index, serum acid uric, pulsatility index in uterine and umbilical arteries and markers of oxidative stress were higher than those found in physiological ones. Moreover, in PE and IUGR, a relation was observed between laboratory and clinical findings and the increased levels of oxidative stress. HTR-8/SVneo and hUMSCs showed reduced viability and increased NO production when stressed with H₂O₂. Finally, HTR-8/SVneo cultured in cross-talk with hUMSCs from pathological pregnancies showed a deterioration of cell viability and NO release when treated with pregnancy-related hormones.

Conclusion

Our findings support that hUMSCs taken from patients affected by PE and IUGR have significant features in comparison with those from physiologic pregnancies. Moreover, the cross-talk between hUMSCs and trophoblast cells might be involved in the etiopathology of IUGR and PE secondary to oxidative stress.