The direct and sustained consequences of severe placental hypoxia on vascular contractility

[Characteristics of the left heart structure and function in 86 term neonates with intrauterine growth restriction]

OBJECTIVES

To study the left heart structure and functional characteristics of term neonates with intrauterine growth restriction (IUGR).

METHODS

This study included 86 term neonates with IUGR admitted to the Neonatal Ward of Beijing Friendship Hospital, Capital Medical University from January 2019 to January 2022 as the IUGR group, as well as randomly selected 86 term neonates without IUGR born during the same period as the non-IUGR group. The clinical data and echocardiographic data were compared between the two groups.

RESULTS

The analysis of left heart structure and function showed that compared with the non-IUGR group, the IUGR group had significantly lower left ventricular mass, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left atrial diameter, end-diastolic interventricular septal thickness, left ventricular posterior wall thickness, left ventricular end-diastolic volume, left ventricular end-systolic volume, and stroke volume (P<0.05) and significantly higher ratio of end-diastolic interventricular septal thickness to left ventricular posterior wall thickness, proportion of neonates with a mitral peak E/A ratio of ≥1, and cardiac index (P<0.05). The Spearman correlation analysis suggested that stroke volume was positively correlated with birth weight and body surface area (rs=0.241 and 0.241 respectively; P<0.05) and that the ratio of end-diastolic interventricular septal thickness to left ventricular posterior wall thickness was negatively correlated with birth weight and body surface area (rs=-0.229 and -0.225 respectively; P<0.05).

CONCLUSIONS

The left ventricular systolic function of neonates with IUGR is not significantly different from that of neonates without IUGR. However, the ventricular septum is thicker in neonates with IUGR. This change is negatively correlated with birth weight and body surface area. The left ventricular diastolic function may be impaired in neonates with IUGR.

Specific dilation pattern in placental circulation and the NO/sGC role in preeclampsia placental vessels

Objective

Endothelial functions in controlling blood flow in placental circulation are still unclear. The present study compares vascular dilations between placental circulation and other vessels, as well as between normal and preeclampsia placental vessels.

Methods

Placental, umbilical, and other vessels (cerebral and mesenteric arteries) were collected from humans, sheep, and rats. Vasodilation was tested by JZ101 and DMT. Q-PCR, Western blot, and Elisa were used for molecular experiments.

Results

Endothelium-dependent/derived vasodilators, including acetylcholine, bradykinin, prostacyclin, and histamine, mediated no or minimal dilation in placental circulation, which was different from that in other vessels in sheep and rats. There were lower mRNA expressions of muscarinic receptors, histamine receptors, bradykinin receptor 2, endothelial nitric oxide synthesis (eNOS), and less nitric oxide (NO) in human umbilical vessels when compared with placental vessels. Exogenous NO donors (sodium nitroprusside, SNP) and soluble guanylate cyclase (sGC) activators (Bay41-2272) decreased the baseline of vessel tone in placental circulation in humans, sheep, and rats, but not in other arteries. The sGC inhibitor ODQ suppressed the reduced baseline caused by the SNP. The decreased baseline by SNP or Bay41-2272 was higher in placental vessels than in umbilical vessels, suggesting that the role of NO/sGC is more important in the placenta. NO concentrations in preeclampsia placental vessels were lower than those in control, while no significant change was found in umbilical plasma between the two groups. eNOS expression was similar between normal and preeclampsia placental vessels, but phosphorylated eNOS levels were significantly lower in preeclampsia. Following serotonin, SNP or Bay41-2272-mediated dilations were weaker in preeclampsia placental vessels. The decreased amplitude of SNP- or Bay41-2272 at baseline was smaller in preeclampsia. The decreased amplitudes of ODQ + SNP were comparable between the two groups. Despite higher beta sGC expression, sGC activity in the preeclampsia placenta was lower.

Conclusion

This study demonstrated that receptor-mediated endothelium-dependent dilation in placental circulation was significantly weaker than other vessels in various species. The results, showed firstly, that exogenous NO played a role in regulating the baseline tone of placental circulation via sGC. Lower NO production and decreased NO/sGC could be one of the reasons for preeclampsia. The findings contribute to understanding specific features of placental circulation and provide information about preeclampsia in placental vessels.

The Impact of Preeclampsia in Lupus Nephritis

INTRODUCTION

Women with systemic lupus erythematosus (SLE), particularly those with lupus nephritis (LN), remain at high risk for adverse pregnancy outcome. Although in the last decades maternal and fetal outcomes have improved dramatically, preeclampsia remains a major cause of maternal and perinatal morbidity and mortality.

AREAS COVERED

A narrative review of literature was conducted, underlying the importance of pre-conception counseling, and focusing on the correlation between preeclampsia and LN. The clinical characteristics of preeclampsia were described, with emphasis on risk factors in LN and the differential diagnosis between preeclampsia and lupus flares. Additionally, the prevention and treatment of preeclampsia were discussed, as well as the management of short-term and long-term consequences of preeclampsia. We highlight the importance of a pre-pregnancy counseling from a multidisciplinary team to plan pregnancy during inactive SLE and LN.

EXPERT OPINION

Further studies are needed to evaluate the long-term consequences of pregnancy in LN. Considering that preeclamptic patients can be at high risk for long-term renal failure, we suggest renal checkup for at least 6-12 months after delivery in all patients.

The clinical effect of aspirin combined with low-molecular-weight heparin in the treatment of severe preeclampsia and the combination's effect on pregnancy outcomes

OBJECTIVE

To explore the clinical effects of aspirin combined with low-molecular-weight heparin (LMWH) in the treatment of patients with severe preeclampsia and the combination's influence on pregnancy outcomes.

METHODS

From October 2018 to June 2020, 104 patients with severe preeclampsia who underwent treatment in our hospital were recruited as the study cohort and divided into two groups according to different treatment scheme each patient underwent. In the research group (RG), the 54 patients were administered aspirin combined with LMWH, and the other 50 patients in the control group (CG) were administered routine treatment. The total effective rates were compared between the two groups. The blood pressure, coagulation function, hemorheology, and renal function indexes were compared before and after the therapy. The Apgar scores of the newborns and the incidences of adverse pregnancy outcomes were measured at 1 and 5 minutes after the births.

RESULTS

After the therapy, the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) in the RG were lower than they were in the CG. The PT and APTT in the RG were significantly higher than they were in the CG, and the FIB and D-D were significantly lower than they were in the CG. After the treatment, the hematocrit, the erythrocyte sedimentation rate, and the plasma viscosity in the RG were significantly lower than they were in the CG. The 24 h UP, BUN, UA, and Scr levels in the RG were significantly lower than they were in the CG. The Apgar scores of the newborns in the RG were significantly higher than they were in the CG at 1 min and 5 min after the births. After the therapy, the incidence of adverse pregnancy outcomes in the RG was significantly lower than it was in the CG, and the total effective rate in the RG was significantly higher than it was in the CG.

CONCLUSION

Aspirin combined with LMWH can effectively improve the clinical efficacy, the coagulation function, the renal function, and the blood pressure levels, and the combination can reduce adverse pregnancy outcomes in severe preeclampsia patients.

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.

Placental Mitochondrial Abnormalities in Preeclampsia

Preeclampsia complicates 5–8% of all pregnancies worldwide, and although its pathophysiology remains obscure, placental oxidative stress and mitochondrial abnormalities are considered to play a key role. Mitochondrial abnormalities in preeclamptic placentae have been described, but the extent to which mitochondrial content and the molecular pathways controlling this (mitochondrial biogenesis and mitophagy) are affected in preeclamptic placentae is unknown. Therefore, in preeclamptic (n = 12) and control (n = 11) placentae, we comprehensively assessed multiple indices of placental antioxidant status, mitochondrial content, mitochondrial biogenesis, mitophagy, and mitochondrial fusion and fission. In addition, we also explored gene expression profiles related to inflammation and apoptosis. Preeclamptic placentae were characterized by higher levels of oxidized glutathione, a higher total antioxidant capacity, and higher mRNA levels of the mitochondrial-located antioxidant enzyme manganese-dependent superoxide dismutase 2 compared to controls. Furthermore, mitochondrial content was significantly lower in preeclamptic placentae, which was accompanied by an increased abundance of key constituents of glycolysis. Moreover, mRNA and protein levels of key molecules involved in the regulation of mitochondrial biogenesis were lower in preeclamptic placentae, while the abundance of constituents of the mitophagy, autophagy, and mitochondrial fission machinery was higher compared to controls. In addition, we found evidence for activation of apoptosis and inflammation in preeclamptic placentae. This study is the first to comprehensively demonstrate abnormalities at the level of the mitochondrion and the molecular pathways controlling mitochondrial content/function in preeclamptic placentae. These aberrations may well contribute to the pathophysiology of preeclampsia by upregulating placental inflammation, oxidative stress, and apoptosis.

Hypoxia-induced mitochondrial abnormalities in cells of the placenta

INTRODUCTION

Impaired utero-placental perfusion is a well-known feature of early preeclampsia and is associated with placental hypoxia and oxidative stress. Although aberrations at the level of the mitochondrion have been implicated in PE pathophysiology, whether or not hypoxia-induced mitochondrial abnormalities contribute to placental oxidative stress is unknown.

METHODS

We explored whether abnormalities in mitochondrial metabolism contribute to hypoxia-induced placental oxidative stress by using both healthy term placentae as well as a trophoblast cell line (BeWo cells) exposed to hypoxia. Furthermore, we explored the therapeutic potential of the antioxidants MitoQ and quercetin in preventing hypoxia-induced placental oxidative stress.

RESULTS

Both in placental explants as well as BeWo cells, hypoxia resulted in reductions in mitochondrial content, decreased abundance of key molecules involved in the electron transport chain and increased expression and activity of glycolytic enzymes. Furthermore, expression levels of key regulators of mitochondrial biogenesis were decreased while the abundance of constituents of the mitophagy, autophagy and mitochondrial fission machinery was increased in response to hypoxia. In addition, placental hypoxia was associated with increased oxidative stress, inflammation, and apoptosis. Moreover, experiments with MitoQ revealed that hypoxia-induced reactive oxygen species originated from the mitochondria in the trophoblasts.

DISCUSSION

This study is the first to demonstrate that placental hypoxia is associated with mitochondrial-generated reactive oxygen species and significant alterations in the molecular pathways controlling mitochondrial content and function. Furthermore, our data indicate that targeting mitochondrial oxidative stress may have therapeutic benefit in the management of pathologies related to placental hypoxia.

Histological villous maturation in placentas of complicated pregnancies

Chorioamnionitis and preeclampsia account for the majority of preterm births worldwide. Thus far, adequate methods for early detection or prevention of these diseases are lacking. In preeclampsia, accelerated villous maturation is believed to compensate placental insufficiency. However, little is known about the effects of placental inflammation in chorioamnionitis on villous maturation. Therefore, we established a set of morphological parameters to evaluate histological villous maturity in pregnancies complicated by chorioamnionitis and preeclampsia. Preterm placentas complicated by chorioamnionitis or preeclampsia were compared to idiopathic preterm placentas and term controls. Histological villous maturation was analyzed by means of 17 histological markers. Fourteen of these markers provided information on absolute and relative numbers of the terminal villi (TV), the extent of their vascularization (using CD31-stained sections) and their exchange capacities. In addition, the numbers of syncytial bridges, syncytial apoptotic knots and shed syncytiotrophoblasts were counted. Accelerated villous maturation in preeclampsia was demonstrated by means of histological villous remodeling and confirmed by 11 relevant markers. Chorioamnionitis, however, only showed increased area of fetal capillaries. In preeclampsia, placentas may transition from growth to maturation earlier than placentas in normal pregnancies, whereas in chorioamnionitis placental changes are more acute and therefore less elaborated at a structural level. Regression analysis suggests the number of all villi and the number of terminal villi as a percentage of all villi as parameters to evaluate histological villous maturity in preeclamptic placentas and to assist diagnosis. However, we would recommend to analyze all 11 relevant parameters to judge placental maturity in detail.