Role of Innate Immunity in Preeclampsia: A Systematic Review

Endothelial activation and damage as a common pathological substrate in different pathologies and cell therapy complications

The endothelium is a biologically active interface with multiple functions, some of them common throughout the vascular tree, and others that depend on its anatomical location. Endothelial cells are continually exposed to cellular and humoral factors, and to all those elements (biological, chemical, or hemodynamic) that circulate in blood at a certain time. It can adapt to different stimuli but this capability may be lost if the stimuli are strong enough and/or persistent in time. If the endothelium loses its adaptability it may become dysfunctional, becoming a potential real danger to the host. Endothelial dysfunction is present in multiple clinical conditions, such as chronic kidney disease, obesity, major depression, pregnancy-related complications, septic syndromes, COVID-19, and thrombotic microangiopathies, among other pathologies, but also in association with cell therapies, such as hematopoietic stem cell transplantation and treatment with chimeric antigen receptor T cells. In these diverse conditions, evidence suggests that the presence and severity of endothelial dysfunction correlate with the severity of the associated disease. More importantly, endothelial dysfunction has a strong diagnostic and prognostic value for the development of critical complications that, although may differ according to the underlying disease, have a vascular background in common. Our multidisciplinary team of women has devoted many years to exploring the role of the endothelium in association with the mentioned diseases and conditions. Our research group has characterized some of the mechanisms and also proposed biomarkers of endothelial damage. A better knowledge would provide therapeutic strategies either to prevent or to treat endothelial dysfunction.

Multimodal profiling of term human decidua demonstrates immune adaptations with pregravid obesity

Leukocyte diversity of the first-trimester maternal-fetal interface has been extensively described; however, the immunological landscape of the term decidua remains poorly understood. We therefore profiled human leukocytes from term decidua collected via scheduled cesarean delivery. Relative to the first trimester, our analyses show a shift from NK cells and macrophages to T cells and enhanced immune activation. Although circulating and decidual T cells are phenotypically distinct, they demonstrate significant clonotype sharing. We also report significant diversity within decidual macrophages, the frequency of which positively correlates with pregravid maternal body mass index. Interestingly, the ability of decidual macrophages to respond to bacterial ligands is reduced with pregravid obesity, suggestive of skewing toward immunoregulation as a possible mechanism to safeguard the fetus against excessive maternal inflammation. These findings are a resource for future studies investigating pathological conditions that compromise fetal health and reproductive success.

Progesterone Enhances the Invasion of Trophoblast Cells by Activating PI3K/AKT Signaling Pathway to Prevent Preeclampsia

We aimed to explore whether the effect of progesterone on preeclampsia via the PI3K/AKT signaling pathway. First, we studied the role of progesterone in preeclampsia patients and HTR-8/Svneo cells by adding progesterone. Then PI3K inhibitor LY294002 was added. The effects of progesterone on preeclampsia were also studied in animals by constructing a preeclampsia rat model. CCK-8 and Transwell assay were applied to measure cell viability and invasion ability. ELISA was performed to measure progesterone, MMP-2, MMP-9, pro-inflammatory factors TNF-α, IL-1β, and anti-inflammatory factors IL-4, IL-10, and IL-13 levels. HE staining was used to detect the pathological changes in uterine spiral artery. Western blot was performed to detect Cyclin D1, PCNA, MMP-2, MMP-9, inflammatory factors TNF-α, IL-1β, IL-4, IL-10, IL-13, and PI3K/AKT signaling pathway related proteins AKT, p-AKT, PI3K, and p-PI3K expressions. Progesterone could reduce blood pressure and urine protein in pregnant women with preeclampsia. TNF-α and IL-1β levels were decreased, but IL-4, IL-10, IL-13, cyclin D1, and PCNA levels were increased in pregnant women with preeclampsia after using progesterone. After the use of progesterone, the symptoms of the PE model group were improved. Among them, the lumen of the placental uterine spiral artery was enlarged, and the fibrinoid necrosis of the uterine wall and acute atherosclerotic lesions were relieved. In addition, progesterone promoted HTR-8/Svneo cells proliferation and invasion. However, high expression of MMP-2, MMP-9, p-AKT, and p-PI3K in Normal and preeclampsia groups caused by progesterone was weakened after adding LY294002, indicating that progesterone could activate PI3K/AKT signaling pathway to regulate HTR-8/Svneo cells. Progesterone decreased urine protein and blood pressure of preeclampsia rats in a concentration-dependent manner. Moreover, progesterone activated the PI3K/AKT signaling pathway and inhibited the inflammatory response in preeclampsia rats.

Vascular Malperfusion – As a Morphological Pattern of Preeclampsia

Introduction. The system « mother-placenta-fetus » is in a complex functional balance, and dysfunction of any of the components can compromise others. The placenta plays an important role in the development of preeclampsia, since preeclampsia can occur in the absence of a fetus, but in the presence of a trophoblast. In this regard, the study of morphological placental patterns in preeclampsia can give an idea of preeclampsia as a pathology in general, as well as its relationship with hypoxic damage to the fetus. Aim.  Identification of morphological patterns of placental lesions associated with preeclampsia. Materials and methods. A retrospective morphological study of 355 placentas sent for histological examination in the period from 2015 to 2020 was carried out. During the analyzed period, 184 placentas from pregnancies with an established diagnosis of preeclampsia and 171 placentas from pregnancies with a physiological course were studied. Results. It has been established that preeclampsia is associated with a smaller mass, size and height of the placenta. As morphological patterns associated with preeclampsia, such histological signs of maternal vascular malperfusion, such as infarcts, arterial atherosclerosis, etc., were identified. Conclusions. The heterogeneity of clinical and histological signs associated with both the physiological and pathological course of pregnancy reflects the different gestational age of the onset of the disease and the stage of development of the adaptive capabilities of the placenta. Identification of morphological patterns associated with hypoxic damage to the fetus allows us to identify a group of newborns with a high risk of chronic hypoxic damage in the perinatal period and to stratify the risk group in the postnatal period in order to reduce infant morbidity and mortality.

Emerging evidence of Toll-like receptors as a putative pathway linking maternal inflammation and neurodevelopmental disorders in human offspring: A systematic review

Inflammation is increasingly recognised to play a major role in gene-environment interactions in neurodevelopmental disorders (NDDs). The effects of aberrant immune responses to environmental stimuli in the mother and in the child can affect neuroimmune signalling that is central to brain development. Toll-like receptors (TLR) are the best known innate immune pattern and danger recognition sensors to various environmental threats. In animal models, maternal immune activation (MIA), secondary to inflammatory factors including maternal gestational infection, obesity, diabetes, and stress activate the TLR pathway in maternal blood, placenta, and fetal brain, which correlate with offspring neurobehavioral abnormalities. Given the central role of TLR activation in animal MIA models, we systematically reviewed the human evidence for TLR activation and response to stimulation across the maternal-fetal interface. Firstly, we included 59 TLR studies performed in peripheral blood of adults in general population (outside of pregnancy) with six chronic inflammatory factors which have epidemiological evidence for increased risk of offspring NDDs, namely, obesity, diabetes mellitus, depression, low socio-economic status, autoimmune diseases, and asthma. Secondly, eight TLR studies done in human pregnancies with chronic inflammatory factors, involving maternal blood, placenta, and cord blood, were reviewed. Lastly, ten TLR studies performed in peripheral blood of individuals with NDDs were included. Despite these studies, there were no studies which examined TLR function in both the pregnant mother and their offspring. Increased TLR2 and TLR4 mRNA and/or protein levels in peripheral blood were common in obesity, diabetes mellitus, depression, autoimmune thyroid disease, and rheumatoid arthritis. To a lesser degree, TLR 3, 7, 8, and 9 activation were found in peripheral blood of humans with autoimmune diseases and depression. In pregnancy, increased TLR4 mRNA levels were found in the peripheral blood of women with diabetes mellitus and systemic lupus erythematosus. Placental TLR activation was found in mothers with obesity or diabetes. Postnatally, dysregulated TLR response to stimulation was found in peripheral blood of individuals with NDDs. This systematic review found emerging evidence that TLR activation may represent a mechanistic link between maternal inflammation and offspring NDD, however the literature is incomplete and longitudinal outcome studies are lacking. Identification of pathogenic mechanisms in MIA could create preventive and therapeutic opportunities to mitigate NDD prevalence and severity.

Association Between TLR4 Gene Polymorphisms and Risk of Preeclampsia: Systematic Review and Meta-Analysis

BACKGROUND Toll-like receptor 4 (TLR4) plays a pivotal role in the innate immune response and is hyperactivated in preeclampsia (PE). Several researchers have published conflicting evidence for TLR4 rs4986790 and rs4986791 single nucleotide polymorphisms (SNPs) as risk factors for PE. The present meta-analysis was conducted to obtain a more definitive conclusion about the effects of these SNPs on PE susceptibility. MATERIAL AND METHODS To determine the correlation between rs4986790 and rs4986791 polymorphisms in the TLR4 gene and susceptibility to PE, the PubMed, Web of Science, EMBASE, Chinese National Knowledge Infrastructure, and Chinese WANFANG databases were searched for eligible articles. Statistical analysis was performed with STATA software, version 12.0. Pooled odds ratios with corresponding 95% confidence intervals (CIs) were extracted for assessment of correlation strength. RESULTS We identified 5 studies including 578 cases and 631 controls for the rs4986790 SNP and 4 studies including 469 cases and 457 controls for the rs4986791 SNP, mainly from a White population. The pooled analyses showed no statistical relationship between the polymorphisms rs4986790 and rs4986791 and PE susceptibility in 5 genetic models (all P>0.05). Moreover, the allelic and dominant gene models of rs4986790 and the allelic, heterozygous, and dominant gene models of rs4986791 had high heterogeneity. The sensitivity analysis explored potential sources of heterogeneity and confirmed the findings of this meta-analysis. CONCLUSIONS TLR4 rs4986790 and rs4986791 polymorphisms may not be implicated in PE susceptibility, primarily in a White population. More high-quality studies of genetic associations with PE are warranted.

Impact of TLR7 and TLR9 polymorphisms on susceptibility to placental infections and pregnancy complications

This study evaluated the impact of the TLR7 Gln11Leu (rs179008) and TLR9 -1237 T/C (rs5743836) single nucleotide polymorphisms (SNPs) on susceptibility to placental infections and pregnancy complications in 455 Brazilian women. Demographic, socioeconomic, gynecological, and clinical characteristics of the women were collected. Placental tissues were sampled from pregnant women and human and viral DNA was extracted. Human alphaherpesvirus 1 (Herpes simplex virus type 1, HSV-1), Human alphaherpesvirus 2 (Herpes simplex virus type 2, HSV-2) and Human betaherpesvirus 5 (Human cytomegalovirus, HCMV) were detected by nested PCR. TLR9 and TLR7 SNPs were genotyped by PCR amplification of bi-directional specific alleles (Bi-PASA) and restriction fragment length polymorphism (RFLP), respectively. Infections at the time of birth were detected in 45.71 % of women. The presence of the TT genotype (recessive model) of the TLR7 SNP was associated with increased susceptibility to HSV-1 infection (O.R. = 2.23, p = 0.05). The presence of the C allele of the TLR9 SNP, in heterozygosis or homozygosis (dominant model), decreased the infection risk by HCMV (O.R. = 0.31, p-mod<0.05). The TT genotype (recessive model) of the TLR7 SNP was significantly associated (p < 0.05) with increased occurrence of pre-treated hypertension. The codominant model of the TLR9 SNP was significantly associated (p < 0.05) with reduced risk of hospitalization during pregnancy. In combination, the AA/CT (TLR7-TLR9) genotypes significantly decreased the risk of placental infection by HSV-1 and/or HSV-2 (O.R. = 0.47, p = 0.02), the susceptibility to all infectious agents considered in combination (O.R. = 0.4, p = 0.00), and the need of hospitalization (O.R. = 0.48, p = 0.02). In conclusion, TLR7 and TLR9 SNPs are potential modulating factors for the risk of placental infections and pregnancy complications.

Advanced maternal age impacts physiologic adaptations to pregnancy in vervet monkeys

The trend to delay pregnancy in the USA has resulted in the number of advanced maternal age (AMA) pregnancies to also increase. In humans, AMA is associated with a variety of pregnancy-related pathologies such as preeclampsia (PE). While AMA is known to be a factor which contributes to the development of pregnancy-induced diseases, the molecular and cellular mechanisms giving rise to this phenomenon are still very limited. This is due in part to lack of a preclinical model which has physiologic relevance to human pregnancy while also allowing control of environmental and genetic variability inherent in human studies. To determine potential physiologic relevance of the vervet/African green monkey (Chlorocebus aethiops sabaeus) as a preclinical model to study the effects of AMA on adaptations to pregnancy, thirteen age-diverse pregnant vervet monkeys (3-16 years old) were utilized to measure third trimester blood pressure (BP), complete blood count, iron measurements, and hormone levels. Significant associations were observed between third trimester diastolic BP and maternal age. Furthermore, the presence of leukocytosis with enhanced circulating neutrophils was observed in AMA mothers compared to younger mothers. Moreover, we observed a negative relationship between maternal age and estradiol, progesterone, and cortisol levels. Finally, offspring born to AMA mothers displayed a postnatal growth retardation phenotype. These studies demonstrate physiologic impairment in the adaptation to pregnancy in AMA vervet/African green monkeys. Our data indicate that the vervet/African green monkey may serve as a useful preclinical model and tool for deciphering pathological mediators of maternal disease in AMA pregnancy.

Biomarkers of placental redox imbalance in pregnancies with preeclampsia and consequent perinatal outcomes

OBJECTIVE

To compare redox and inflammatory markers between normal and PE-derived placentas and to evaluate the relationship between placental redox imbalance markers and perinatal outcomes in pregnancies with PE.

METHODS

This was a cross-sectional study conducted at the maternity hospital of a university hospital in Maceio-Alagoas, Brazil, in 2017, including women diagnosed with PE and healthy pregnant women and their conceptuses. After screening, standardized questionnaires containing socioeconomic, clinical, obstetric and anthropometric data were applied. After delivery, placental samples were collected for quantification of biomarkers of redox imbalance (catalase - CAT; malondialdehyde - MDA; hydrogen peroxide - H₂O₂; superoxide dismutase - SOD; reduced glutathione - GSH; oxidized glutathione - GSSG; and their ratio - GSH/GSSG) and inflammation (myeloperoxidase - MPO; interleukin (IL)-6; IL-8; IL-10; and tumor necrosis factor-alpha - TNF-α). All biomarkers were evaluated via linear regression with adjustments of variables with measures of weight, length, head circumference (HC), chest circumference (CC) and gestational age of newborns at birth, considering p < 0.05 as significant.

RESULTS

A total of 100 pregnant women with PE and 50 healthy pregnant women were studied. Higher placental levels of catalase (p = 0.018), SOD (p = 0.031), the GSH/GSSG ratio (p = 0.019) and IL-6 (p = 0.010) and lower GSSG (p = 0.001) were observed in pregnant women with PE than in the control group. Positive associations between placental GSH levels and body weight, HC, CC and gestational age at birth (p < 0.05) were identified.

CONCLUSION

PE-derived placentas had high concentrations of some antioxidants (enzymes and thiols), which might be a compensation mechanism against oxidative stress. Placental GSH levels were the only biomarker, among the studied ones, related positively with beneficial perinatal outcomes, suggesting that this endogenous antioxidant plays an important role in maintaining the health of the conceptus and women with PE.

Analyses of interleukin-6, presepsin and pentraxin-3 in the diagnosis and severity of late-onset preeclampsia

Introduction: The etiology/pathophysiology of preeclampsia remains an enigma. Maternal inflammation (humoral and cellular) is a key factor in the etiology of late-onset preeclampsia (L-PrE). Presepsin is split out from the phagocytes membranes after phagocytosis. It is known as a novel inflammation marker. To our knowledge, this is the first study in literature in English to investigate maternal blood concentrations of presepsin in preeclampsia and healthy pregnant women.Methods: We examined maternal plasma interleukin-6, presepsin and pentraxin-3 concentrations in pregnant women with (n = 44) and without L-PrE (n = 44). These three inflammatory markers concentrations measured using enzyme-linked immunosorbent assays were compared.Results: The mean maternal age and gestational age at sampling are similar in the both groups (p ≥ .05). Interleukin-6, presepsin and pentraxin-3 concentrations differed between the groups (p < .05). There was no difference between the three inflammatory markers concentrations in patients with mild (22 patients) and severe (22 patients) preeclampsia in L-PrE (p ≥ .05). A significant discriminative role of interleukin-6, presepsin and pentraxin-3 for presence of L-PrE, with cutoff values of 39.74 pg/mL, 309.88 mg/L and 34.96 ng/mL, respectively, were reported in a ROC curve analysis. When the patients with and without small for gestational age infants (12 patients and 76 patients, respectively) were compared, it was determined that there was no differences between the interleukin-6, but there were differences between the presepsin and pentraxin-3 concentrations (p = .016, p = .008, respectively).Conclusion: Lower concentrations of interleukin-6/presepsin and higher concentrations of pentraxin-3 were associated with the development of preeclampsia. Further investigations of inflammatory/immunity markers in pregnancy are required and may ultimately lead to novel therapeutic approaches to treat complications of pregnancy.

Association of maternal Toll-like receptor-4 alleles with susceptibility to early-onset preeclampsia in central Greece

INTRODUCTION

Altered maternal inflammatory responses may play a role in the development of hypertensive disorders of pregnancy like preeclampsia, its more severe early-onset form and intrauterine growth restriction. We evaluated the relation of common allelic variants of Toll-like receptor 4 (TLR4), known to impair the inflammatory response, with the susceptibility to early-onset preeclampsia in Central Greece.

METHODS

We compared the occurrence of TLR4 (Asp299Gly and Thr399Ile) alleles in heterozygous (A/G, C/T) and homozygous (G/G, T/T) states in 84 women with a history of early-onset preeclampsia and 94 age matched controls with a history of only uneventful pregnancies, by direct sequencing.

RESULTS

Heterozygous TLR4 allelic variants were more common in women with a history of early-onset preeclampsia than in controls (GA for Asp299Gly: 14.3% vs 6.4% (AA), p = 0.053 & CT for Thr399Ile: 16.7% vs. 6.4% (CC), p = 0.019) and a stronger association was obtained when homozygous allelic carriers were also included (GA/GG for Asp299Gly: 16.7% vs. 6.4% (AA), p = 0.03 & TC/TT for Thr399Ile: 19.0% vs. 6.4% (CC), p = 0.01).

DISCUSSION

We recorded association between common TLR4 gene variants and early-onset preeclampsia. Our findings support the involvement of maternal innate immune system in severe hypertensive disorders of pregnancy and point to the potential value of maternal TLR4 polymorphisms as predictors-risk factors of susceptibility to early-onset preeclampsia in Central Greece.

Impact of pregravid obesity on maternal and fetal immunity: Fertile grounds for reprogramming

Maternal pregravid obesity results in several adverse health outcomes during pregnancy, including increased risk of gestational diabetes, preeclampsia, placental abruption, and complications at delivery. Additionally, pregravid obesity and in utero exposure to high fat diet have been shown to have detrimental effects on fetal programming, predisposing the offspring to adverse cardiometabolic, endocrine, and neurodevelopmental outcomes. More recently, a deeper appreciation for the modulation of offspring immunity and infectious disease-related outcomes by maternal pregravid obesity has emerged. This review will describe currently available animal models for studying the impact of maternal pregravid obesity on fetal immunity and review the data from clinical and animal model studies. We also examine the burden of pregravid obesity on the maternal-fetal interface and the link between placental and systemic inflammation. Finally, we discuss future studies needed to identify key mechanistic underpinnings that link maternal inflammatory changes and fetal cellular reprogramming events.

Toll-like receptors signaling network in pre-eclampsia: An updated review

Toll-like receptors (TLRs) are innate immune cells receptors. They are expressed on leukocytes, epithelial cells, and more particularly on placental immune cells and chorion trophoblast. Upregulation of innate immune response occurs during normal pregnancy, but its excessive activity is involved in the pathology of pregnancy complications including pregnancy-induced hypertension and pre-eclampsia (PE). The recent studies about the overmuch inflammatory responses and aberrant placentation are associated with increased expression of TLRs in PE patients. This review has tried to focus on the relationship between some activities of TLRs and the risk of preeclampsia development.

[Change in the expression of the NLRP3 inflammasome signaling pathway in peripheral blood and its significance in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To investigate the expression of the NLRP3 inflammasome signaling pathway in peripheral blood and its significance in children with Mycoplasma pneumoniae pneumonia (MPP).

METHODS

According to the severity, 147 children with MPP were divided into mild group with 83 children and severe group with 64 children. According to the stage of disease, the children were divided into acute group with 77 children and recovery stage with 70 children. A total of 50 healthy children were enrolled as the control group. Quantitative real-time PCR was used to measure the mRNA expression of NLRP3, ASC, and caspase-1. ELISA was used to measure the serum levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18).

RESULTS

Compared with the control group, the children with MMP had significantly higher relative mRNA expression levels of NLRP3, ASC, and caspase-1 in peripheral blood and serum levels of IL-1β and IL-18 (P<0.05). Compared with the control group, both mild and severe groups had significantly higher relative mRNA expression levels of NLRP3, ASC, and caspase-1 in peripheral blood and serum levels of IL-1β and IL-18 (P<0.05). The severe group had significantly higher levels of above mentioned parameters than the mild group (P<0.05). Both acute group and recovery group had significantly higher relative mRNA expression levels of NLRP3, ASC, and caspase-1 in peripheral blood and serum levels of IL-1β and IL-18 than the control group (P<0.05). The acute group had significantly higher levels of above mentioned parameters than the recovery group (P<0.05). The relative expression level of NLRP3 was positively correlated with the relative mRNA expression levels of ASC and caspase-1 and the serum levels of IL-1β and IL-18 (r=0.701, 0.717, 0.676, and 0.645 respectively; P<0.05).

CONCLUSIONS

The NLRP3 inflammasome signaling pathway might be involved in the pathogenesis of MPP in children and is closely associated with the severity and course of the disease.