Toll-like receptor activation, vascular endothelial function, and hypertensive disorders of pregnancy

Pregnancy as an Early Cardiovascular Moment: Peripartum Cardiovascular Health

Pregnancy is commonly referred to as a window into future CVH (cardiovascular health). During pregnancy, physiological adaptations occur to promote the optimal growth and development of the fetus. However, in approximately 20% of pregnant individuals, these perturbations result in cardiovascular and metabolic complications, which include hypertensive disorders of pregnancy, gestational diabetes, preterm birth, and small-for-gestational age infant. The biological processes that lead to adverse pregnancy outcomes begin before pregnancy with higher risk of adverse pregnancy outcomes observed among those with poor prepregnancy CVH. Individuals who experience adverse pregnancy outcomes are also at higher risk of subsequent development of cardiovascular disease, which is largely explained by the interim development of traditional risk factors, such as hypertension and diabetes. Therefore, the peripartum period, which includes the period before (prepregnancy), during, and after pregnancy (postpartum), represents an early cardiovascular moment or window of opportunity when CVH should be measured, monitored, and modified (if needed). However, it remains unclear whether adverse pregnancy outcomes reflect latent risk for cardiovascular disease that is unmasked in pregnancy or if adverse pregnancy outcomes are themselves an independent and causal risk factor for future cardiovascular disease. Understanding the pathophysiologic mechanisms and pathways linking prepregnancy CVH, adverse pregnancy outcomes, and cardiovascular disease are necessary to develop strategies tailored for each stage in the peripartum period. Emerging evidence suggests the utility of subclinical cardiovascular disease screening with biomarkers (eg, natriuretic peptides) or imaging (eg, computed tomography for coronary artery calcium or echocardiography for adverse cardiac remodeling) to identify risk-enriched postpartum populations and target for more intensive strategies with health behavior interventions or pharmacological treatments. However, evidence-based guidelines focused on adults with a history of adverse pregnancy outcomes are needed to prioritize the prevention of cardiovascular disease during the reproductive years and beyond.

Phosphoglycerate mutase 5 promotes necroptosis in trophoblast cells through activation of dynamin-related protein 1 in early-onset preeclampsia

OBJECTIVES

Placentae from patients with preeclampsia have increased susceptibility to necroptosis and phosphoglycerate mutase 5 (PGAM5) plays a role in many necrosis pathways. We determined whether PGAM5 promotes necroptosis of trophoblast cells and the underlying mechanisms in this study.

METHODS

The injury model was established by treating JEG3 cells with hypoxia for 24 h. The functional measurements were assessed by the cell counting kit-8, propidium iodide (PI)/Annexin V staining, JC-1 staining and firefly luciferase ATP assay. The expression of proteins in human placentae and JEG3 cells was measured Western blot. PGAM5 was knocked down to study its role in hypoxia-induced necroptosis.

RESULTS

The placentae from patients with preeclampsia showed up-regulation of PGAM5 and decreased levels of p-Drp1-S637, accompanied by increased necroptosis-relevant proteins expression. The expression of PGAM5 in JEG3 cells was up-regulated under hypoxia, which promoted dephosphorylation of Drp1 at Serine 637 residue, mitochondrial dysfunction (elevated ROS level and reduced mitochondrial membrane potential and ATP content) and cellular necroptosis (increased PI⁺ /Annexin V⁺ cells and decreased cell viability), accompanied by increased expression of necroptosis-relevant proteins; knockdown of PGAM5 attenuated these phenomena.

CONCLUSIONS

Our results indicate that PGAM5 can promote necroptosis in trophoblast cells through, at least in part, activation of Drp1. It may be used as a new therapeutic target to prevent trophoblast dysfunction in preeclampsia.

A review of key cytokines based on gene polymorphism in the pathogenesis of pre-eclampsia

Although a number of theories have been suggested, including roles for oxidative stress, an abnormal maternal-fetal interface, and genetic and environmental factors, the etiopathology of pre-eclampsia (PE) remains unclear. Maternal immune tolerance is important for maintaining pregnancy, and researchers have increasingly focused on the critical roles of cytokines in the pathogenesis of PE in recent years. The assessment of candidate genetic polymorphisms in PE could partially elucidate the mechanisms of susceptibility to disease, and contribute to seeking for new diagnosis and treatment methods of PE. PE can lead to severe complications, and even the death of both mother and fetus. Although the complex pathology is not yet clear, some evidence suggested that the occurrence of PE is related to inflammatory factors. We reviewed the current understandings of roles of cytokines in PE, and provided an extensive overview of the role of single nucleotide chain polymorphisms (SNPs) in the genes potentially underlying the pathophysiology of PE.

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.

Magnesium Lithospermate B Downregulates the Levels of Blood Pressure, Inflammation, and Oxidative Stress in Pregnant Rats with Hypertension

Background

Magnesium lithospermate B (MLB) was shown to suppress oxidative stress and reduce hypertension, but the role of MLB in pregnancy-induced hypertension (PIH) remains unknown. The objective of this study was to demonstrate the effects of MLB on rats with PIH.

Methods

A total of 40 pregnant SD rats were selected, and 30 rats were orally given NG-nitro-L-arginine methyl ester (L-NAME, 60 mg/kg/day) to establish PIH rat models. Rats were equally divided into four groups: control, PIH, 5 mg/kg MLB, and 10 mg/kg MLB. MLB was consecutively administered into PIH rats for one week. The effects of MLB on mean arterial blood pressure (MAP), urine protein level, inflammation, and oxidative stress together with angiogenesis were analyzed.

Results

MLB prevented the elevation in MAP and urine protein levels induced by L-NAME. The activities of inflammatory cytokines were highly increased in serum and placental tissues of PIH rats, while cotreatment with MLB partially reversed the activities of these cytokines. MLB also recovered the expression of reactive oxygen species (ROS) in plasma of PIH rats together with levels of oxidative stress and antioxidant capacity in the placenta of PIH rats. The decreased expressions of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), and NO observed in PIH rats were increased by MLB. In addition, 10 mg/kg MLB exhibited higher protective effects as compared to lower doses of 5 mg/kg.

Conclusion

This study demonstrated that pretreatment with MLB decreased MAP, inflammation, and oxidative stress in rats with gestational hypertension.

Dendritic cell biology and its role in tumor immunotherapy

As crucial antigen presenting cells, dendritic cells (DCs) play a vital role in tumor immunotherapy. Taking into account the many recent advances in DC biology, we discuss how DCs (1) recognize pathogenic antigens with pattern recognition receptors through specific phagocytosis and through non-specific micropinocytosis, (2) process antigens into small peptides with proper sizes and sequences, and (3) present MHC-peptides to CD4⁺ and CD8⁺ T cells to initiate immune responses against invading microbes and aberrant host cells. During anti-tumor immune responses, DC-derived exosomes were discovered to participate in antigen presentation. T cell microvillar dynamics and TCR conformational changes were demonstrated upon DC antigen presentation. Caspase-11-driven hyperactive DCs were recently reported to convert effectors into memory T cells. DCs were also reported to crosstalk with NK cells. Additionally, DCs are the most important sentinel cells for immune surveillance in the tumor microenvironment. Alongside DC biology, we review the latest developments for DC-based tumor immunotherapy in preclinical studies and clinical trials. Personalized DC vaccine-induced T cell immunity, which targets tumor-specific antigens, has been demonstrated to be a promising form of tumor immunotherapy in patients with melanoma. Importantly, allogeneic-IgG-loaded and HLA-restricted neoantigen DC vaccines were discovered to have robust anti-tumor effects in mice. Our comprehensive review of DC biology and its role in tumor immunotherapy aids in the understanding of DCs as the mentors of T cells and as novel tumor immunotherapy cells with immense potential.

The relationship among vitamin D, TLR4 pathway and preeclampsia

Preeclampsia is a pregnancy-specific syndrome that has been the greatest cause of maternal and fetal morbidity and mortality. The impaired outcomes are related to maternal and the offspring healthy in the short and long-term. Although preeclampsia origins remain unclear, it is well known that there is impaired trophoblast invasion with culminant abnormal immune response. The early and late-onset preeclampsia have been studied, the subtypes have the same difference in the placentation and inflammatory features. Dietary compounds can stimulate or inhibit the activation of immune cells. Low vitamin D intake has been linked to impaired fetal development, intrauterine growth restriction, and preeclampsia. Vitamin D has been described as an anti-inflammatory effect. It can downregulate pro-inflammatory cytokines expression by the inhibition of the Nuclear Factor-ĸB pathway signaling cascade. High vitamin D levels could attenuate the immune response. On the other hand, vitamin D deficiency may contribute to increasing pro-inflammatory state. In preeclampsia, there is a reduced expression of vitamin D receptor and its metabolism is disrupted. In this review, we aimed to discuss the role of vitamin D as an anti-inflammatory agent in relation to the pro-inflammatory process of preeclampsia through the activation of the TLR4 pathway. Although there are limited studies showing the relation between vitamin D and lower risk of preeclampsia, the maternal status of vitamin D seems to influence the risk of PE development. Therefore, vitamin D supplementation in women may be a strategy to improve pregnancy outcomes.

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.

Vascular Inflammation Risk Factors in Retinal Disease

Inflammation of the blood vessels that serve the central nervous system has been increasingly identified as an early and possibly initiating event among neurodegenerative conditions such as Alzheimer's disease and related dementias. However, the causal relevance of vascular inflammation to major retinal degenerative diseases is unresolved. Here, we describe how genetics, aging-associated changes, and environmental factors contribute to vascular inflammation in age-related macular degeneration, diabetic retinopathy, and glaucoma. We highlight the importance of mouse models in studying the underlying mechanisms and possible treatments for these diseases. We conclude that data support vascular inflammation playing a central if not primary role in retinal degenerative diseases, and this association should be a focus of future research.

Modulation of trophoblast function by concurrent hyperglycemia and antiphospholipid antibodies is in part TLR4-dependent

PROBLEM

While diabetes and APS are individually associated with increased risk of poor perinatal outcomes, in particular preeclampsia, recent studies have demonstrated an association between concurrent aPL and diabetes leading to an increased risk of pregnancy morbidity. Hyperglycemia and aPL have independently been shown to alter human trophoblast function by inducing a pro-inflammatory, anti-angiogenic, and antimigratory response. However, little is known about the effects of concurrent hyperglycemia and aPL on trophoblast function.

METHOD OF STUDY

A human first-trimester extravillous trophoblast cell line was exposed to glucose at 5 mmol/L (normoglycemia) or 25 mmol/L (hyperglycemia), all in the presence or absence of low-dose aPL or control IgG. For some experiments, the TLR4 antagonist, LPS-RS, was included. Cell culture supernatants were measured for inflammatory IL-1β and IL-8, and angiogenic PlGF, sFlt-1, and sEndoglin by ELISA. Inflammasome-associated uric acid was measured using a bioassay; caspase-1 was measured using an activity assay. Trophoblast migration was quantified using a two-chamber colorimetric assay.

RESULTS

Compared to excess glucose alone, combination excess glucose and low-dose aPL (a) further augmented trophoblast inflammatory IL-1β, inflammasome-associated uric acid and caspase-1, and pro-angiogenic PlGF; (b) dampened trophoblast inflammatory IL-8, anti-angiogenic sEndoglin, and sFlt-1; and (c) further reduced trophoblast migration.

CONCLUSION

Our findings indicate that while concurrent aPL and hyperglycemia are overall detrimental to trophoblast function, the presence of two simultaneous insults triggers some protective effects.

No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases

Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.

Pre-eclampsia affects procalcitonin production in placental tissue

PROBLEM

Procalcitonin (PCT) is the prohormone of calcitonin which is usually released from neuroendocrine cells of the thyroid gland (parafollicular) and the lungs (K cells). PCT is synthesized by almost all cell types and tissues, including monocytes and parenchymal tissue, upon LPS stimulation. To date, there is no evidence for PCT expression in the placenta both in physiological and pathological conditions.

METHOD

Circulating and placental PCT levels were analysed in pre-eclamptic (PE) and control patients. Placental cells and macrophages (PBDM), stimulated with PE sera, were analysed for PCT expression. The effect of anti-TNF-α antibody was analysed.

RESULTS

Higher PCT levels were detected in PE sera and in PE placentae compared to healthy women. PE trophoblasts showed increased PCT expression compared to those isolated from healthy placentae. PE sera induced an upregulation of PCT production in macrophages and placental cells. The treatment of PBDM with PE sera in the presence of anti-TNF-α completely abrogated the effect induced by pathologic sera.

CONCLUSION

Trophoblast cells are the main producer of PCT in PE placentae. TNF-α, in association with other circulating factors present in PE sera, upregulates PCT production in macrophages and normal placental cells, thus contributing to the observed increased in circulating PCT in PE sera.