Endoglin pathway genetic variation in preeclampsia: A validation study in Norwegian and Latina cohorts

Human uterine natural killer cells regulate differentiation of extravillous trophoblast early in pregnancy

In humans, balanced invasion of trophoblast cells into the uterine mucosa, the decidua, is critical for successful pregnancy. Evidence suggests that this process is regulated by uterine natural killer (uNK) cells, but how they influence reproductive outcomes is unclear. Here, we used our trophoblast organoids and primary tissue samples to determine how uNK cells affect placentation. By locating potential interaction axes between trophoblast and uNK cells using single-cell transcriptomics and in vitro modeling of these interactions in organoids, we identify a uNK cell-derived cytokine signal that promotes trophoblast differentiation at the late stage of the invasive pathway. Moreover, it affects transcriptional programs involved in regulating blood flow, nutrients, and inflammatory and adaptive immune responses, as well as gene signatures associated with disorders of pregnancy such as pre-eclampsia. Our findings suggest mechanisms on how optimal immunological interactions between uNK cells and trophoblast enhance reproductive success.

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.

Preeclampsia Prevalence, Risk Factors, and Pregnancy Outcomes in Sweden and China

IMPORTANCE

Preeclampsia is a leading cause of maternal and perinatal morbidity and mortality worldwide. Within-country studies have reported racial differences in the presentation and outcome, but little is known about differences between countries.

OBJECTIVE

To compare preeclampsia prevalence, risk factors, and pregnancy outcomes between the Swedish and Chinese populations.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study compared deliveries from the Swedish national Medical Birth Register (2007-2012) and the China Labor and Delivery Survey (2015-2016). The Swedish Medical Birth Register records maternal, pregnancy, and neonatal information for nearly all deliveries in Sweden. The China Labor and Delivery Survey was conducted throughout China, and these data were reweighted to enable national comparisons. Participants included 555 446 deliveries from Sweden and 79 243 deliveries from China. Data management and analysis was conducted from November 2018 to August 2020 and revised in February to March 2021.

EXPOSURES

Maternal characteristics, parity, multiple gestation, chronic and gestational diabetes, cesarean delivery.

MAIN OUTCOMES AND MEASURES

Preeclampsia prevalence and risk factors, overall and for mild and severe forms and rates of adverse neonatal outcomes compared with pregnancies with no gestational hypertension.

RESULTS

The 555 446 Swedish pregnancies and 79 243 Chinese pregnancies had mean (SD) maternal age of 30.9 (5.3) years and 28.6 (4.6) years, respectively. The overall prevalence of preeclampsia was similar in Sweden and China, 16 068 (2.9%) and 1803 (2.3%), respectively, but with 5222 cases (32.5%) considered severe in Sweden and 1228 cases (68.1%) considered severe in China. Obesity (defined as BMI ≥28 in China and BMI ≥30 in Sweden) was a stronger risk factor in China compared with Sweden (China: odds ratio [OR], 5.12; 95% CI, 3.82-6.86; Sweden: OR, 3.49; 95% CI, 3.31-3.67). Nulliparity had a much stronger association with severe preeclampsia in Sweden compared with China (Sweden: OR, 3.91; 95% CI, 3.65-4.18; China: OR, 1.65; 95% CI, 1.20-2.25). The overall stillbirth rate for singleton in China was more than 3-fold higher than in Sweden (846/77 512[1.1%] vs 1753/547 219 [0.3%], P < .001), and 10-fold higher among women with preeclampsia (66/1652 [4.6%] vs 60/14 499[0.4%], P < .001).

CONCLUSIONS AND RELEVANCE

In this study, the prevalence rates of preeclampsia in Sweden and China were similar, but women in China had more severe disease and worse pregnancy outcomes than women in Sweden. The associations of obesity and nulliparity with preeclampsia suggest a role for lifestyle and health care factors but may reflect some differences in pathophysiology. These findings have relevance for current efforts to identify high-risk pregnancies and early serum markers because the value of risk prediction models and biomarkers may be population specific.

Gene polymorphism associated with TGF-β1 and susceptibility to preeclampsia: A meta-analysis and trial sequential analysis

AIM

Mounts of researches focused on the link between transforming growth factor-beta 1 (TGF-β1) polymorphisms and preeclampsia (PE) which is a hypertensive multisystemic disorder affecting pregnancy. However, the results were inconsistent. Thus, a meta-analysis was performed to obtain more conclusive results.

METHODS

Eligible studies were searched in PubMed, Web of Science, EMBASE, and Scopus. Odds ratios (ORs) with 95% confidence intervals (CIs) were utilized to evaluate the relationship between six TGF-β1 polymorphisms (rs1800468, rs1800469, rs1800470, rs1800471, rs4803455, and rs4803457) and PE susceptibility in five genetic models. The subgroup stratified analysis and trial sequential analysis were performed.

RESULTS

Fourteen studies were included in this meta-analysis with 1941 PE patients and 2488 healthy women. There was no statistically significant association between these six TGF-β1 polymorphisms and PE within five genetic models in the overall population (all p > 0.05). Subgroup stratified analysis revealed there was statistically significant association between TGF-β1 rs1800469 polymorphism and PE within the allele, recessive, and homozygous model in Asian (OR = 1.17, 95% CI = 1.02-1.35; OR = 1.35, 95% CI = 1.06-1.72; OR = 1.48, 95% CI = 1.07-2.05, respectively; all p < 0.05). Trial sequential analysis indicated sufficient proof of such association in the Asian population.

CONCLUSIONS

TGF-β1 rs1800469 is a possible risk factor for PE in Asian populations.

Analyses of soluble endoglin and matrix metalloproteinase 14 using enzyme-linked immunosorbent assay in the diagnosis and assessment of severity of early- and late-onset pre-eclampsia

Objective

Abnormal trophoblastic invasion and impaired placentation have a crucial role in the etiopathogenesis of preeclampsia (PrE). Trophoblastic cells are involved in invading the maternal decidua and remodelling of the spiral arteries with matrix metalloproteinase-14 (MMP-14). MMP-14 cleavage of endoglin releases its extracellular region, the soluble form of endoglin (s-ENG), into the maternal circulation. In PrE, there is a relationship between endothelial dysfunction and s-ENG concentration. The aim was to determine and compare the serum levels of s-ENG and MMP-14 in different groups of PrE patients and healthy subjects.

Material and Methods

The study included 30 patients with late-onset preeclampsia (L-PrE) (group 1; gestational age ≥34 weeks), 33 patients with normal pregnancy (group 2; gestational age ≥34 weeks), 31 patients early-onset preeclampsia (E-PrE) (group 3; gestational age <34 weeks), and 31 patients with normal pregnancy (group 4; gestational age <34 weeks). s-ENG and MMP-14 concentrations measured using enzyme-linked immunosorbent assays were compared.

Results

In all groups, MMP-14 concentrations decreased with increasing gestational age. s-ENG concentrations were highest in the E-PrE group. In groups 1 and 3, 29 had mild PrE while 32 suffered severe PrE and s-ENG concentrations did not differ between mild and severe preeclampsia (p=0.133). However, there was a significant difference in MMP-14 concentration comparing mild with severe PrE (3.11±0.61 vs 3.54±1.00; p=0.047, respectively). There was no correlation between s-ENG and MMP-14 concentrations.

Conclusion

MMP-14 and s-ENG concentrations can be predictive biomarkers for the diagnosis of PrE. Maternal serum MMP-14 concentration may be a biomarker for determining the severity of PrE.

Polyunsaturated Fatty Acid Diet and Upregulation of Lipoxin A4 Reduce the Inflammatory Response of Preeclampsia

The aim of this study was to investigate the effects and mechanisms of polyunsaturated fatty acids (PUFAs) and lipoxin A4 (LXA4) on preeclampsia (PE). The LXA4 level was significantly reduced in PE rats. The PUFA diet upregulated the expressions of lipoxygenase 12 (LOX12) and lipoxygenase 15 (LOX15) and downregulated those of cyclooxygenase-2, tumor necrosis factor-α (TNF-α), and endoglin. Lipopolysaccharides could inhibit cell growth and cause inflammatory response, while the presence of PUFAs inhibited the inflammatory response and promoted the expressions of LOX12, LOX15, and LXA4. Nordihydroguaiaretic acid (NDGA) regulated LXA4 expression and inflammation levels by affecting LOX. Inhibition of lipoxygenase 5 activity by NDGA upregulated the expressions of LOX12 and LOX15, while LXA4 reversed LXA4, nitric oxide downregulation, and TNF-α upregulation by NDGA. A decrease in LXA4 levels played an important role in the development and progression of PE.

DNA Methylation of Endoglin Pathway Genes in Pregnant Women With and Without Preeclampsia

Objective

We compared blood-based DNA methylation levels of endoglin (ENG) and transforming growth factor beta receptor 2 (TGFβR2) gene promoter regions between women with clinically-overt preeclampsia and women with uncomplicated, normotensive pregnancies.

Methods

We used EpiTect Methyl II PCR Assays to evaluate DNA methylation of CpG islands located in promoter regions of ENG (CpG Island 114642) and TGFβR2 (CpG Island 110111). Preeclampsia was diagnosed based on blood pressure, protein, and uric acid criteria. N = 21 nulliparous preeclampsia case participants were 1:1 frequency matched to N = 21 nulliparous normotensive control participants on gestational age at sample collection (±2 weeks), smoking status, and labor status at sample collection. Methylation values were compared between case and control participant groups [(ENG subset: n = 20 (9 cases, 11 controls); TGFβR2 subset: n = 28 (15 cases, 13 controls)].

Results

The majority of the preeclampsia cases delivered at ⩾34 weeks' gestation (83%). Average methylation levels for ENG ([M ± (SD)]; Case Participant Group = 6.54% ± 4.57 versus Control Participant group = 4.81% ± 5.08; P = .102) and TGFβR2 (Case Participant Group = 1.50% ± 1.37 vs Control Participant Group = 1.70% ± 1.40; P = .695) promoter CpG islands did not differ significantly between the participant groups. Removal of 2 extreme outliers in the ENG analytic subset revealed a trend between levels of ENG methylation and pregnancy outcome (Case Participant Group = 5.17% ± 2.16 vs Control Participant Group = 3.36% ± 1.73; P = .062).

Conclusion

Additional epigenetic studies that include larger sample sizes, investigate preeclampsia subtypes, and capture methylation status of CpG island shores and shelves are needed to further inform us of the potential role that ENG and TGFβR2 DNA methylation plays in preeclampsia pathophysiology.

Pathophysiology of the Venous Thromboembolism Risk in Preeclampsia

Preeclampsia complicates up to 8% of pregnancies and is a leading cause of fetomaternal morbidity andmortality. Treatment options are limited, with supportive care and delivery of the placenta representing the cornerstone of current management strategies. Derangements in blood coagulation are wellrecognised in this disorder and appear to favour an increased risk of venous thromboembolism among affected women. This risk appears to be most significant in the postpartum period. The mechanisms underlying this increased thrombosis risk remain to be fully elucidated although increased expression of procoagulant factors, endothelial dysfunction, attenuation of endogenous anticoagulant activity and increased platelet activity have been implicated in the prothrombotic tendency. Preeclampsia is also occasionally complicated by life-threatening haemorrhagic events and current evidence suggests that in some severe manifestations of this disease a coagulopathy with a clinical bleeding tendency may be the predominant haemostatic abnormality. Identifying affected women at significant risk of thrombosis and managing the competing thrombotic and haemorrhagic risks continue to be a significant clinical challenge. Derangements in blood coagulation are also implicated in the pathogenesis of preeclampsia; however, the role of antiplatelet or anticoagulant drugs in the prevention and treatment of this disorder remains a source of considerable debate. In addition, the potential role of specific haemostatic markers as diagnostic or screening tools for preeclampsia has also yet to be determined. Further characterisation of the underlying molecular mechanisms would likely be of major translational relevance and could provide insights into the pathogenesis of this disease as well as the associated haemostatic dysfunction.

An Insight into the Angiogenic and Lymphatic Interplay in Pre-eclampsia Comorbid with HIV Infection

PURPOSE OF REVIEW

To provide insight on the imbalance of angiogenic and lymphangiogenic factors in pre-eclampsia, as well as highlight polymorphism in genes related to angiogenesis and lymphangiogenesis.

RECENT FINDINGS

The pregnancy-specific disorder pre-eclampsia is diagnosed by the presence of hypertension with/without proteinuria, after 20 weeks of gestation. The pathogenesis of pre-eclampsia remains ambiguous, but research over the years has identified an imbalance in maternal and foetal factors. Familial predisposition and gene variation are also linked to pre-eclampsia development. The sFlt-1/PIGF ratio has attracted great attention over the years; more recently several researchers have reported that a sFlt-1/PIGF ratio of ≤ 38 can be used to predict short-term absence of pre-eclampsia. This ratio has the potential to prevent adverse pregnancy outcomes and reduce healthcare costs significantly. Genome-wide studies have additionally identified variation in the foetal gene near Flt-1. The development of preeclampsia is not limited to the maternal interface, but foetal involvement as well as genetic interplay is associated with the disorder.

The transforming growth factor β superfamily as possible biomarkers of preeclampsia: a comprehensive review

The etiology of preeclampsia - an abnormal placentation-mediated disease - is not fully understood; and there are very few biomarkers with which to predict and diagnose it. Early prediction and diagnosis of this pathology can lead to a significant improvement in maternal and perinatal outcomes. Since members of the transforming growth factor β superfamily influence placentation, and are released from the placenta into the maternal circulatory system, several studies have investigated the involvement of these cytokines in preeclampsia and the possibility of using their serum levels as biomarkers of the disease. In this review, we have summarized the reported relationships between the levels of this superfamily of cytokines and preeclampsia. The available information indicates that altered levels of some of these cytokines are involved in the pathogenesis and pathophysiology of preeclampsia, suggesting their likelihood of serving as predictive and diagnostic biomarkers of the disease.

Interleukin-23 receptor (IL-23R) gene polymorphisms and haplotypes associated with the risk of preeclampsia: evidence from cross-sectional and in silico studies

PURPOSE

Pre-eclampsia is a relatively common pregnancy disorder. Serum concentrations of certain pro-inflammatory molecules and cytokines like interleukin-23 may affect the pathogenesis of pre-eclampsia. The interleukin-23 receptor (IL-23R) gene plays an important role in the progression of inflammatory and autoimmune diseases and IL-23 polymorphisms might influence the susceptibility of pre-eclampsia. The aim of the recent study was to establish the association between IL-23R gene polymorphisms and the susceptibility for developing of pre-eclampsia.

METHODS

One hundred and fifty-eight pregnant patients with pre-eclampsia and 153 controls were genotyped using RFLP-PCR and AS-PCR. Also, an in silico analysis was performed to predict possible effects of these variations on IL-23R mRNA and protein structures.

RESULTS

The frequency of the AG genotype of rs11209026 is related to a higher risk of pre-eclampsia. The mutant C and A allele in rs10889677 and rs11209026 SNPs, respectively, are correlated with the risk of pre-eclampsia and they are more frequent in severe late onset PE. We found higher frequency of the haplotype CG in patients with pre-eclampsia in comparison to healthy controls, as well as, the CG haplotype frequency significantly increased the risk of PE in severe, early onset, and late onset sub-groups. The results of computational analysis predicted rs11209026 and rs10889677 SNPs as functional variations, which can influence IL-23R mRNA and protein.

CONCLUSIONS

The results of present study show positive association between polymorphisms in the IL-23R gene and pre-eclampsia. Therefore, the presence of IL-23R rs11209026, rs10889677 polymorphism might be markers for the genetic susceptibility to pre-eclampsia.

Down-regulated miR-149-5p contributes to preeclampsia via modulating endoglin expression

OBJECTIVE

Endoglin is expressed in human placenta and plays an important role in the pathogenesis of preeclampsia. Dysregulation of microRNAs in placental tissues has been recently suggested to be involved in the pathogenesis of preeclampsia. Until now, few studies have shed light on the correlation between endoglin and microRNAs, the latter of which may regulate the expression of ENG, a gene encoding endoglin, in placenta. In this study, we aim to investigate the regulation of ENG by microRNAs.

STUDY DESIGN

We located the microRNAs that might regulate the expression of ENG. Candidate microRNAs were tested if they had an impact on trophoblast function.

MAIN OUTCOME MEASURES

We compared endoglin expression between normotensive and preeclamptic placentas by using immunohistochemistry and real-time PCR. Downregulated microRNAs in preeclamptic placenta were revealed from a literature review. A bioinformatics assay was performed to predict those that might target ENG. Real-time PCR, Western blotting and dual luciferase assay were used to verify the targeting. The effects of the microRNAs on trophoblasts were evaluated by transwell invasion assay.

RESULTS

The endoglin level was significantly higher in preeclamptic placenta than in normotensive placenta. ENG was validated as the direct target of miR-149-5p and was inversely correlated with it. MiR-149-5p promoted the invasion of trophoblast cells, and this promotion was abrogated by the overexpression of ENG.

CONCLUSIONS

Our findings highlight the importance of miR-149-5p in the pathogenesis of preeclampsia and provide new insight into the development of the disease.