Heme oxygenase induction attenuates TNF-α-induced hypertension in pregnant rodents

Therapeutic effect of E-Lip-siRNA-sFlt1 on pre-eclampsia: targeted gene silencing and improved pregnancy outcomes

Aim: To evaluate a liposome complex conjugated with anti-epidermal growth factor receptor (EGFR) antibodies for the treatment of pre-eclampsia (PE).Methods: In in vitro experiments, the transfection rate, silencing effect and cytotoxicity were determined. In the in vivo PE model, the siRNA distribution, mean arterial pressure, 24-h urine protein concentration, serum sFlt1 concentration, number of viable fetuses and placental weight were measured.Results: The nanomedicine effectively reduced the expression of sFIt1 and had a strong ability to target placental tissues. It could significantly reduce the symptoms of pre-eclampsia and improve pregnancy outcomes in PE model rats.Conclusion: The constructed nanomedicine can improve pregnancy outcomes in a rat model of pre-eclampsia and provides a new strategy for the treatment of pre-eclampsia.

Luteolin prevents TNF-α-induced NF-κB activation and ROS production in cultured human placental explants and endothelial cells

INTRODUCTION

Preeclampsia (PE) is a serious hypertensive pregnancy disorder and a leading cause of maternal and perinatal morbidity and mortality. Despite the prevalence and complications, there are no approved therapeutics to relieve PE symptoms. Inflammation, oxidative stress, and angiogenic imbalance have been shown to contribute to the PE pathophysiology, though there is a lack of understanding in how best to target these pathways in PE. We recently demonstrated that the bioflavonoid luteolin is a potent inhibitor of the anti-angiogenic and pro-hypertensive soluble fms-like tyrosine kinase 1 (sFlt-1), and here we aimed to determine if luteolin was also capable of reducing inflammation and oxidative stress pathways.

METHODS

Tumor necrosis factor (TNF)-α, which is upregulated in PE, was utilized to stimulate these pathways in human placental explants and endothelial cells. Endothelin-1 (ET-1) and interleukin (IL)-6 in the media from explants and cells were measured via ELISA, and NF-κB localization and reactive oxygen species were detected via fluorescence microscopy.

RESULTS

Pretreatment with luteolin demonstrated significant reductions in NF-κB activation, reactive oxygen species, superoxide, and IL-6 and ET-1 expression in endothelial cells. We also saw a significant reduction in phosphorylation of NF-κB in human placental explants.

DISCUSSION

These data demonstrate that luteolin inhibits pathways implicated in the development of PE and should be explored further for its potential as a PE therapeutic.

Role of blood-borne factors in sympathoexcitation-mediated hypertension: Potential neurally mediated hypertension in preeclampsia

Hypertension remains a threat for society due to its unknown causes, preventing proper management, for the growing number of patients, for its state as a high-risk factor for stroke, cardiac and renal complication and as cause of disability. Data from clinical and animal researches have suggested the important role of many soluble factors in the pathophysiology of hypertension through their neuro-stimulating effects. Central targets of these factors are of molecular, cellular and structural nature. Preeclampsia (PE) is characterized by high level of soluble factors with strong pro-hypertensive activity and includes immune factors such as proinflammatory cytokines (PICs). The potential neural effect of those factors in PE is still poorly understood. Shedding light into the potential central effect of the soluble factors in PE may advance our current comprehension of the pathophysiology of hypertension in PE, which will contribute to better management of the disease. In this paper, we summarized existing data in respect of hypothesis of this review, that is, the existence of the neural component in the pathophysiology of the hypertension in PE. Future studies would address this hypothesis to broaden our understanding of the pathophysiology of hypertension in PE.

Reliability of Rodent and Rabbit Models in Preeclampsia Research

In vivo studies on the pathology of gestation, including preeclampsia, often use small mammals such as rabbits or rodents, i.e., mice, rats, hamsters, and guinea pigs. The key advantage of these animals is their short reproductive cycle; in addition, similar to humans, they also develop a haemochorial placenta and present a similar transformation of maternal spiral arteries. Interestingly, pregnant dams also demonstrate a similar reaction to inflammatory factors and placentally derived antiangiogenic factors, i.e., soluble fms-like tyrosine kinase 1 (sFlt-1) or soluble endoglin-1 (sEng), as preeclamptic women: all animals present an increase in blood pressure and usually proteinuria. These constitute the classical duet that allows for the recognition of preeclampsia. However, the time of initiation of maternal vessel remodelling and the depth of trophoblast invasion differs between rabbits, rodents, and humans. Unfortunately, at present, no known animal replicates a human pregnancy exactly, and hence, the use of rabbit and rodent models is restricted to the investigation of individual aspects of human gestation only. This article compares the process of placentation in rodents, rabbits, and humans, which should be considered when planning experiments on preeclampsia; these aspects might determine the success, or failure, of the study. The report also reviews the rodent and rabbit models used to investigate certain aspects of the pathomechanism of human preeclampsia, especially those related to incorrect trophoblast invasion, placental hypoxia, inflammation, or maternal endothelial dysfunction.

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.

Acetylcholinesterase inhibition with Pyridostigmine attenuates hypertension and neuroinflammation in the paraventricular nucleus in rat model for Preeclampsia

Preeclampsia (PE) is characterized by hypertension, autonomic imbalance and inflammation. The subfornical organ (SFO) reportedly relays peripheral inflammatory mediator's signals to the paraventricular nucleus (PVN), a brain autonomic center shown to mediate hypertension in hypertensive rat but not yet in PE rat models. Additionally, we previously showed that Pyridostigmine (PYR), an acetylcholinesterase inhibitor, attenuated placental inflammation and hypertension in PE models. In this study, we investigated the effect of PYR on the activities of these brain regions in PE model. PYR (20 mg/kg/day) was administered to reduced uterine perfusion pressure (RUPP) Sprague-Dawley rat from gestational day (GD) 14 to GD19. On GD19, the mean arterial pressure (MAP) was recorded and samples were collected for analysis. RUPP rats exhibited increased MAP (P = 0.0025), elevated circulating tumor necrosis factor-α (TNF-α, P = 0.0075), reduced baroreflex sensitivity (BRS), increased neuroinflammatory markers including TNF-α, interleukin-1β (IL-1β), microglial activation (P = 0.0039), oxidative stress and neuronal excitation within the PVN and the SFO. Changes in MAP, in molecular and cellular expression induced by RUPP intervention were improved by PYR. The ability of PYR to attenuate TNF-α mediated central effect was evaluated in TNF-α-infused pregnant rats. TNF-α infusion-promoted neuroinflammation in the PVN and SFO in dams was abolished by PYR. Collectively, our data suggest that PYR improves PE-like symptoms in rat by dampening placental ischemia and TNF-α-promoted inflammation and pro-hypertensive activity in the PVN. This broadens the therapeutical potential of PYR in PE.

Pyridostigmine ameliorates preeclamptic features in pregnant rats by inhibiting tumour necrosis factor-α synthetsis and antagonizing tumour necrosis factor-α-related effects

OBJECTIVE

Preeclampsia is a hypertensive disorder of pregnancy marked by an excessive inflammatory response. The anti-inflammatory effect of pyridostigmine (PYR) was previously reported; however, its role in hypertensive pregnancies remains unclear. We hypothesized that PYR could attenuate increased blood pressure and other pathological features in preeclampsia models.

METHODS

The expression of tumour necrosis factor (TNF)-α was evaluated in normal and preeclampsia pregnant women. PYR (20 mg/kg) was administered daily to reduced uterine perfusion pressure (RUPP) and TNF-α (150 ng/day) infused rats from gestation day 14 to GD19. In a cell culture experiment, the effect of acetylcholine (ACh) on TNF-α-stimulated primary human umbilical endothelial cells (HUVEC) was assessed.

RESULTS

Preeclampsia women had higher placental TNF-α expression than normal pregnant women. Mean arterial pressure (MAP) in the RUPP group was higher than in the Sham group. PYR inhibited serum and placental acetylcholinesterase activity in rats, and reduced MAP, placental oxidative stress, apoptosis and inflammation in the RUPP group but not in the Sham group. In addition, PYR significantly attenuated the TNF-α-induced increase in MAP, placental oxidative stress and apoptosis. Moreover, TNF-α decreased cell viability and increased the number of TUNEL-positive nuclei of HUVEC, which could largely be abolished by ACh treatment.

CONCLUSION

Collectively, PYR ameliorated hypertension and other preeclampsia-like symptoms in rat models of preeclampsia not only by inhibiting the synthesis of TNF-α but also by acting against TNF-α-induced detrimental effects directly, which is worthy of further investigation and may be used as a potential agent for preeclampsia management.

Preeclampsia: Linking Placental Ischemia with Maternal Endothelial and Vascular Dysfunction

Preeclampsia (PE), a hypertensive disorder, occurs in 3% to 8% of pregnancies in the United States and affects over 200,000 women and newborns per year. The United States has seen a 25% increase in the incidence of PE, largely owing to increases in risk factors, including obesity and cardiovascular disease. Although the etiology of PE is not clear, it is believed that impaired spiral artery remodeling of the placenta reduces perfusion, leading to placental ischemia. Subsequently, the ischemic placenta releases antiangiogenic and pro-inflammatory factors, such as cytokines, reactive oxygen species, and the angiotensin II type 1 receptor autoantibody (AT1-AA), among others, into the maternal circulation. These factors cause widespread endothelial activation, upregulation of the endothelin system, and vasoconstriction. In turn, these changes affect the function of multiple organ systems including the kidneys, brain, liver, and heart. Despite extensive research into the pathophysiology of PE, the only treatment option remains early delivery of the baby and importantly, the placenta. While premature delivery is effective in ameliorating immediate risk to the mother, mounting evidence suggests that PE increases risk of cardiovascular disease later in life for both mother and baby. Notably, these women are at increased risk of hypertension, heart disease, and stroke, while offspring are at risk of obesity, hypertension, and neurological disease, among other complications, later in life. This article aims to discuss the current understanding of the diagnosis and pathophysiology of PE, as well as associated organ damage, maternal and fetal outcomes, and potential therapeutic avenues. © 2021 American Physiological Society. Compr Physiol 11:1315-1349, 2021.

Acetylcholine ameliorated TNF-α-induced primary trophoblast malfunction via muscarinic receptors†

Oxidative stress and apoptosis of trophoblasts are involved in preeclampsia (PE). Numerous studies have shown that acetylcholine (ACh), the principal vagal neurotransmitter, plays a crucial role in attenuating oxidative stress, inflammation, and apoptosis in a variety of human diseases. However, the role of ACh in PE management remains unclear. Here, we aimed to determine the effects of ACh on TNF-α-treated human primary trophoblast cells. Western blotting, CCK-8, DHE, TUNEL immunofluorescence staining, transwell assays, and wound-healing assays were performed to evaluate the role of ACh in vitro. We found that both TNF-α expression and the apoptotic index were higher in placentas from preeclamptic women than in normal placentas. TNF-α enhanced oxidative stress and increased the number of TUNEL-positive nuclei, Bax/Bcl-2 ratio, and the cleaved caspase-3/caspase-3 ratio while decreasing cell viability in primary human trophoblast cells. TNF-α promoted cell migration and invasion. PDTC, a selective NF-κB inhibitor, significantly blunted TNF-α-induced effects. ACh treatment attenuated oxidative stress and apoptosis while further promoting migration and invasion of TNF-α-treated primary trophoblast cells. The effects of ACh could be reversed by the muscarinic receptor antagonist atropine. Overall, our findings indicate that ACh significantly ameliorates TNF-α-induced oxidative stress and apoptosis of human primary trophoblast cells via muscarinic receptors. This is the first time that the improvement of vagal activity served as a therapeutic strategy for PE-like trophoblasts, suggesting its potential value in clinical practice.

Pathophysiology of Cerebral Vascular Dysfunction in Pregnancy-Induced Hypertension

PURPOSE OF REVIEW

To review and summarize what is known about cerebrovascular derangements during preeclampsia.

RECENT FINDINGS

Preeclampsia is a devastating disorder of pregnancy with no known cure. Little is known about the pathophysiological mechanisms which lead to the symptoms of the disorder, particularly with regard to individual vascular beds such as the cerebral circulation. Studies suggest that the cerebrovascular dysfunction characteristic of the preeclampsia syndrome is characterized by alterations in cerebral blood flow autoregulation and opening of the blood-brain barrier. Mechanistic studies demonstrate that the same circulating factors implicated in the pathophysiology of other vascular beds may be operative in the cerebral circulation as well. However, significant knowledge gaps still exist, highlighting the need for more intense research in this field. Little is known about cerebrovascular dysfunction during preeclampsia, and detailed mechanistic studies are needed to identify the molecular pathways involved, the interactions thereof, and how those pathways lead to clinical disease.

Influence of serum HMW adiponectin level in patients with pregnancy-induced hypertension syndrome on the occurrence of eclampsia in secondary pregnancy

In the present study, we studied the influence of serum high-molecular weight adiponectin (HMWA) levels in patients with pregnancy-induced hypertension (PIH) on the occurrence of eclampsia in secondary pregnancy and its related mechanisms. In total, 130 patients who were diagnosed with PIH for the first time were selected for this study; the median interval of the secondary pregnancy was 28.5 months. The serum HMWA and leptin levels both times were detected, and the insulin resistance indexes (HOMA-IR) were calculated. The serum inflammatory indexes in the secondary pregnancy included interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels, and the oxidative stress indexes included methane dicarboxylic aldehyde (MDA) and oxidized low-density lipoprotein (ox-LDL) levels. The expression levels of adiponectin receptor 2 and cyclooxygenase-2 (COX-2) in placental tissue were detected. In secondary pregnancy, there were a total of 20 cases of eclampsia (15.38%), including 2 cases of mild PIH, 8 cases of moderate PIH and 10 cases of severe PIH; differences were statistically significant when compared to patients without eclampsia (p<0.001). The serum HMWA levels in patients with severe PIH in the first pregnancy were significantly lower than those in patients with mild and moderate PIH, and the serum levels in patients with mild PIH were the highest. The leptin levels in patients with severe PIH were significantly higher than those in patients with mild and moderate PIH, and the leptin levels in patients with mild PIH were the lowest (p<0.05). The HMWA levels in patients with eclampsia in the secondary pregnancy was significantly lower than those in patients without eclampsia, and the leptin levels in patients with eclampsia were significantly increased. The HMWA levels in patients with eclampsia in the secondary pregnancy were lower than that in the first pregnancy, whereas the leptin levels were higher than that in the first pregnancy (p<0.05). HOMA-IR, IL-6, TNF-α, MDA and ox-LDL levels in patients with eclampsia were significantly higher than those in patients without eclampsia (p<0.05), and the adiponectin receptor 2 and COX-2 expression levels in the placental tissue were significantly higher than those in patients without eclampsia (p<0.05). Therefore, the serum HMWA levels are closely related to the occurrence of eclampsia in PIH patients in secondary pregnancy, and it influences insulin resistance, inflammatory response and oxidative stress response, which is correlated with increased adiponectin receptor 2 and COX-2 protein expression in placental tissue. Consequently, HMWA may be an important target for the intervention of preventing eclampsia for PIH patients in secondary pregnancy.

Carbon Monoxide Releasing Molecules Blunt Placental Ischemia-Induced Hypertension

BACKGROUND

Preeclampsia is a pregnancy complication which manifests as new-onset hypertension, proteinuria, and a spectrum of other symptoms. While the underlying causes are still a subject of much debate, it is commonly believed that placental ischemia is a central cause. The ischemic placenta secretes factors which are believed to be responsible for the maternal syndrome; most notably the anti-angiogenic protein soluble fms-like tyrosine kinase 1 (sFlt-1). We have reported that induction of the carbon monoxide (CO) producing protein heme oxygenase-1 restored angiogenic imbalance and reduced blood pressure in a rat model of placental ischemia, and that CO blocks hypoxia-induced sFlt-1 production from placental tissue in vitro. We therefore hypothesized that direct administration of CO by a CO-releasing molecule (CORM) would blunt the placental ischemia-induced increase in sFlt-1 and thus the hypertension characteristic of this model.

METHODS

We administered a soluble CO donor molecule (CORM-3) daily i.v. in control animals or those undergoing placental ischemia from GD14. Blood pressure and renal function were measured on GD19, and angiogenic markers measured by ELISA.

RESULTS

Interestingly, though we found that CORM administration significantly blunted the hypertensive response to placental ischemia, there was no concomitant normalization of sFlt-1 in either the placenta or maternal circulation. We did find, however, that CORM administration caused a significant increase in glomerular filtration rate, presumably by vasodilation of the renal arteries and increased renal plasma flow.

CONCLUSIONS

All in all these data suggest that administration of CO by CORMs do lower blood pressure during placental ischemia mechanisms independent of changes in angiogenic balance.

Preeclampsia and the brain: neural control of cardiovascular changes during pregnancy and neurological outcomes of preeclampsia

Preeclampsia (PE) is a form of gestational hypertension that complicates ∼5% of pregnancies worldwide. Over 70% of the fatal cases of PE are attributed to cerebral oedema, intracranial haemorrhage and eclampsia. The aetiology of PE originates from abnormal remodelling of the maternal spiral arteries, creating an ischaemic placenta that releases factors that drive the pathophysiology. An initial neurological outcome of PE is the absence of the autonomically regulated cardiovascular adaptations to pregnancy. PE patients exhibit sympathetic overactivation, in comparison with both normotensive pregnant and hypertensive non-pregnant females. Moreover, PE diminishes baroreceptor reflex sensitivity (BRS) beyond that observed in healthy pregnancy. The absence of the cardiovascular adaptations to pregnancy, combined with sympathovagal imbalance and a blunted BRS leads to life-threatening neurological outcomes. Behaviourally, the increased incidences of maternal depression, anxiety and post-traumatic stress disorder (PTSD) in PE are correlated to low fetal birth weight, intrauterine growth restriction (IUGR) and premature birth. This review addresses these neurological consequences of PE that present in the gravid female both during and after the index pregnancy.