Preeclamptic Women Have Decreased Circulating IL-10 (Interleukin-10) Values at the Time of Preeclampsia Diagnosis: Systematic Review and Meta-Analysis

A loss of tuning of both pro-coagulant and inflammatory responses in monocytes in patients with preeclampsia

An imbalance between pro- and anti-angiogenesis is one of the leading causes of preeclampsia (PE). Monocytes, known as regulators of angiogenesis during immune responses, cooperate with platelets, but the specifics of these responses during pregnancy remain unclear. In this study, we investigated the relationship between pro-coagulant responses on monocytes [platelet activation marker CD61 as a monocyte-platelet aggregate (MPA), tissue factor (CD142), etc.], inflammatory responses [soluble CD40 ligand (sCD40L), soluble suppression of tumorigenesis-2 (sST2), etc.], and the balance of angiogenesis [soluble Fms-related receptor tyrosine kinase 1/placental growth factor (sFlt-1/PLGF) ratio]. In PE, markers of pro-coagulant and inflammatory responses were higher than those in normal pregnancy (NP). Interestingly, in NP, these markers harmonized with the sFlt-1/PLGF ratio, but not in PE. Furthermore, ex vivo examinations showed that upregulation of CD142 induced by additional platelet activation with adenosine diphosphate was diminished in PE. Conversely, low-dose aspirin, which is used as a preventive treatment for PE, could inhibit the increase of CD61 and sST2 under inflammatory stimuli and platelet activation in NP but not in PE. These results indicate that monocytes in PE upregulate basal activity and lose responsiveness to stimulation. The elevation of pro-coagulant and inflammatory responses may be mitigated by prophylaxis with low-dose aspirin. Therefore, the findings suggesting a loss of tuning of both pro-coagulant and inflammatory responses on monocytes help in understanding the pathology of PE. The harmonization between pro-coagulant responses, inflammatory responses, and angiogenesis may serve as useful indicators for the prediction and preventive treatment of PE.

Short term air pollution exposure during pregnancy and associations with maternal immune markers

BACKGROUND

Air pollution exposure during pregnancy has been associated with numerous adverse pregnancy, birth, and child health outcomes. One proposed mechanism underlying these associations is maternal immune activation and dysregulation. We examined associations between PM2.5 and NO2 exposure during pregnancy and immune markers within immune function groups (TH1, TH2, TH17, Innate/Early Activation, Regulatory, Homeostatic, and Proinflammatory), and examined whether those associations changed across pregnancy.

METHODS

In a pregnancy cohort study (n = 290) in Rochester, New York, we measured immune markers (using Luminex) in maternal plasma up to 3 times during pregnancy. We estimated ambient PM2.5 and NO2 concentrations at participants' home addresses using a spatial-temporal model. Using mixed effects models, we estimated changes in immune marker concentrations associated with interquartile range increases in PM2.5 (2.88 μg/m3) and NO2 (7.82 ppb) 0-6 days before blood collection, and assessed whether associations were different in early, mid, and late pregnancy.

RESULTS

Increased NO2 concentrations were associated with higher maternal immune markers, with associations observed across TH1, TH2, TH17, Regulatory, and Homeostatic groups of immune markers. Furthermore, the largest increases in immune markers associated with each 7.82 ppb increase in NO2 concentration were in late pregnancy (e.g., IL-23 = 0.26 pg/ml, 95% CI = 0.07, 0.46) compared to early pregnancy (e.g., IL-23 = 0.08 pg/ml, 95% CI = -0.11, 0.26).

CONCLUSIONS

Results were suggestive of NO2-related immune activation. Increases in effect sizes from early to mid to late pregnancy may be due to changes in immune function over the course of pregnancy. These findings provide a basis for immune activation as a mechanism for previously observed associations between air pollution exposure during pregnancy and reduced birthweight, fetal growth restriction, and pregnancy complications.

The Enigmatic Interplay of Interleukin-10 in the Synergy of HIV Infection Comorbid with Preeclampsia

Cytokines coordinate the intricate choreography of the immune system, directing cellular activities that mediate inflammation, pathogen defense, pathology and tissue repair. Within this spectrum, the anti-inflammatory prowess of interleukin-10 (IL-10) predominates in immune homeostasis. In normal pregnancy, the dynamic shift of IL-10 across trimesters maintains maternal immune tolerance ensuring fetal development and pregnancy success. Unravelling the dysregulation of IL-10 in pregnancy complications is vital, particularly in the heightened inflammatory condition of preeclampsia. Of note, a reduction in IL-10 levels contributes to endothelial dysfunction. In human immunodeficiency virus (HIV) infection, a complex interplay of IL-10 occurs, displaying a paradoxical paradigm of being immune-protective yet aiding viral persistence. Genetic variations in the IL-10 gene further modulate susceptibility to HIV infection and preeclampsia, albeit with nuanced effects across populations. This review outlines the conceptual framework underlying the role of IL-10 in the duality of normal pregnancy and preeclampsia together with HIV infection, thus highlighting its regulatory mechanisms and genetic influences. Synthesizing these findings in immune modulation presents avenues for therapeutic interventions in pregnancy complications comorbid with HIV infection.

Immunological mechanisms in preeclampsia: A narrative review

Maternal immunologic mechanisms for tolerance are essential for a successful pregnancy because they prevent maladaptive immune responses to the placenta and semi-allogeneic fetus and promote fetal growth. Preeclampsia is a major global cause of fetal mortality and morbidity. It is characterized by new-onset hypertension and proteinuria that occurs at twenty weeks of pregnancy or later. Preeclampsia is defined by a rise in cytokines that are pro-inflammatory and antiangiogenic components in the fetoplacental unit and the vascular endothelium of pregnant women, as well as an excessive and increasing stimulation of the immune system. Crucially, inflammation can result in low birth weight and inadequate placental perfusion in neonates. Preeclampsia, which is ultimately connected to inflammatory responses, can be impacted by several immunological mechanisms. Our goal in this work was to compile the most recent research on the pathoimmunology of preeclampsia, including studies on angiogenic variables and, in particular, immunological components.

The causal role of circulating immunity-inflammation in preeclampsia: A Mendelian randomization

Patients with systemic autoimmune diseases, such as systemic lupus erythematosus, were at a higher risk for preeclampsia. The causal relationship between immunological inflammation and preeclampsia (PE) remains uncertain. We aimed to investigate the causal relationship between circulating immune inflammation and PE. Genetically predicted blood immune cells and circulating inflammatory proteins were identified using two genome-wide association studies (GWAS). We used a two-sample Mendelian randomization (MR) method to determine whether circulating immunological inflammation causes PE. Our findings indicated that ten immunophenotypes were identified to be significantly associated with PE risk: CD62L- Dendritic Cell Absolute Count, CD86+ myeloid Dendritic Cell %Dendritic Cell, CD62L- myeloid Dendritic Cell Absolute Count, CD86+ myeloid Dendritic Cell Absolute Count, CD62L- myeloid Dendritic Cell %Dendritic Cell, CD62L- CD86+ myeloid Dendritic Cell %Dendritic Cell, CD62L- CD86+ myeloid Dendritic Cell Absolute Count, CD16 on CD14+ CD16+ monocyte, HLA DR+ Natural Killer Absolute Count, and T cell Absolute Count. Ninety-one inflammation-related proteins had no statistically significant effect on PE following false discovery rate (FDR) correction. Certain proteins exhibited unadjusted low p-values that merited mention. These proteins include interleukin-10 (OR = 0.76, 95%CI = 0.63-0.93, p = .006), fibroblast growth factor 21 (OR = 1.23, 95%CI = 1.01-1.47, p = .035), and Caspase 8 (OR = 0.65, 95%CI = 0.50-0.85, p = .001). The ELISA analysis demonstrated elevated levels of FGF-21 and decreased levels of IL-10 and Caspase-8 in the plasma of patients with PE. These findings reveal that immunophenotypes and circulating inflammatory proteins may induce PE, confirming the importance of peripheral Immunity-Inflammation in PE. The discovery has the potential to lead to earlier detection and more effective treatment techniques.

Evaluation of maternal serum VEGF, TNF-alpha, IL-4, and IL-10 levels in differentiating placenta accreta spectrum from isolated placenta previa

OBJECTIVE

Our study aimed to differentiate patients with placenta accreta spectrum (PAS) from those with placenta previa (PP) using maternal serum levels of vascular endothelial growth factor (VEGF), tumor necrosis factor-alpha (TNF-alpha), interleukin-4 (IL-4), and IL-10.

METHODS

The case group consisted of 77 patients with placenta previa, and the control group consisted of 90 non-previa pregnant women. Of the pregnant women in the case group, 40 were diagnosed with PAS in addition to placenta previa and 37 had placenta previa with no invasion. The maternal serum VEGF, TNF-alpha, IL-4, and IL-10 levels were compared between the case and control groups. Then the success of these markers in differentiating between PP and PAS was evaluated.

RESULTS

We found the VEGF, TNF-alpha, and IL-4 levels to be higher and the IL-10 level to be lower in the case group compared to the control group (p < 0.001). We observed a statistically significantly lower IL-10 level in the patients with PAS than those with PP (p = 0.029). In the receiver operating characteristic analysis, the optimal cut-off of IL-10 in the detection of PAS was 0.42 ng/mL). In multivariate analysis, the risk of PAS was significant for IL-10 (odds ratio (OR) 0.45, 95 % confidence interval (CI) 0.25-0.79, p = 0.006) and previous cesarean section (OR 2.50, 95 % Cl 1.34-4.66, p = 0.004). The model's diagnostic sensitivity and specificity, including previous cesarean section, preoperative hemoglobin (Hb), TNF-alpha, and IL-10 were 75 % and 72.9 %, respectively.

CONCLUSION

The study showed that the IL-10 level was lower in patients with PAS than in those with PP. A statistical model combining risk factors including previous cesarean section, preoperative Hb, TNF-alpha, and IL-10 may improve clinical diagnosis of PAS in placenta previa cases. Cytokines may be used as additional biomarkers to the clinical risk factors in the diagnosis of PAS.

Phthalate exposure increases interferon-γ during pregnancy: The Atlanta African American Maternal-Child Cohort

BACKGROUND

The immune system undergoes unique adaptations during pregnancy and is particularly sensitive to environmental chemicals, such as phthalates, which are associated with acute and chronic inflammatory medical conditions. However, current knowledge of how phthalate exposures are associated with systemic inflammation in pregnant people is limited by cross-sectional study designs and single chemical models. Our objective was to estimate the association between repeated measures of prenatal phthalate exposures, examined individually and collectively, and a panel of clinical inflammatory biomarkers.

METHODS

In the Atlanta African American Maternal-Child Cohort, biospecimens were collected at mean 11 and 26 weeks gestation (N = 126). Concentrations of eight urinary phthalate metabolites and five serum inflammatory biomarkers, including CRP, IFN-γ, IL-6, IL-10, and TNF-α, were measured. Linear mixed effect regression and quantile g-computation models were used to estimate the associations for single phthalates and their exposure mixture, respectively.

RESULTS

Participants who self-reported any use of alcohol, tobacco, or marijuana in the month prior to pregnancy had increased MEP, MBP, MiBP, and CRP, relative to those with no substance use. IFN-γ was elevated in response to MECPP (% change = 17.35, 95 % confidence interval [CI] = 0.32, 32.27), MEHHP (% change = 12.75, 95 % CI = 2.22, 24.36), MEOHP (% change = 11.63, 95 % CI = 1.21, 23.12), and their parent phthalate, ΣDEHP (% change = 15.03, 95 % CI = 0.28, 31.94). The phthalate mixture was also associated with an increase in IFN-γ (% change = 15.03, 95 % CI = 6.18, 24.61).

CONCLUSIONS

Our findings suggest DEHP metabolites induce systemic inflammation during pregnancy. The pro-inflammatory cytokine IFN-γ may play an important role in the relationship between prenatal phthalate exposures and adverse pregnancy outcomes.

Circulating levels of cytokines (IL-6, IL-10 and TGF- β) and CD4+CD25+FOXP3+Treg cell population in recurrent pregnancy loss

Recurrent pregnancy loss (RPL), a serious reproductive health issue, characterized by two or more pregnancy losses before 20th week of gestation. Globally, it affects 2-5% couples and the basis of the crisis is still unknown in 50% cases. Successful pregnancy is associated with pro and anti-inflammatory gestational phases that tolerate the semi-allogenic foetus, and disturbance leads to pregnancy complications like RPL. This case-control study aimed to assess the inflammatory status in the mid-gestation of ongoing pregnancy of women with (RPL) and without (NRPL) the history of RPL. Blood samples were processed for PBMC isolation, subjected to Flow-cytometry for CD4+CD25+FOXP3+Treg-cell population count and serum samples for IL-6, TGF-β, IL-10 cytokine levels (ELISA). Significant reduction in the percentage of Treg cells, and elevated values for IL-6/TGF-β and IL-6/IL-10 ratios were observed in RPL over NRPL group (p = 0.0001). Opposing results were seen with respect to the magnitude of history of RPL (2 vs. >2 losses). ROC curve analysis showed the superior discriminatory ability of cytokine ratios (IL-6/TGF-β > IL-6/IL-10) for RPL over Treg cells. Our findings are suggestive of pro-inflammatory dominance in mid-gestation of pregnant women with a history of RPL in general and greater than normal anti-inflammatory milieu in cases with > 2 pregnancy loss. As both sterile and infection related inflammation plays a role in pregnancy loss, studies enrolling women with favourable and unfavourable ongoing pregnancies may shed light on the importance of the present study for developing better management/therapeutic strategies.

Increased ferroptosis in leukocytes from preeclamptic women involving the long non-coding taurine upregulated gene 1 (TUG1)

BACKGROUND

Ferroptosis plays a key role in placental development and physiology, and abnormal ferroptosis has been implicated in trophoblast injury leading to preeclampsia (PE). We hypothesize that leukocytes isolated from PE exhibit increased ferroptosis and that extracellular vesicles contain long non-coding (lnc) RNA/mRNAs that modulate oxidative stress and iron toxicity in vascular endothelial cells.

METHODS

We measured the expression of key regulators of ferroptosis in leukocytes and extracellular vesicles as well as circulating biomarkers of iron homeostasis and oxidative stress in plasma from women with/without PE at different timepoints during pregnancy. For markers that were dysregulated, we assessed their temporal correlation with established markers of disease activity and marker of endothelial activation. For markers dysregulated in early pregnancy, we assessed their ability to predict the development of PE.

RESULTS

We found decreased lncRNA/mRNAs in leukocytes, but not extracellular vesicles, in PE that may modulate oxidative stress and iron toxicity. This decrease in anti-ferroptotic markers does not appear to be related to maternal disease activity or plasma oxidative stress status but rather to attenuated anti-inflammatory expression in these cells. Circulating ferritin was elevated in PE, supporting the hypothesis that PE represents a disbalance in iron homeostasis. Low lncRNA taurine upregulated gene 1 RNA levels in leukocytes at 22-24 weeks were strongly associated with the development of PE.

CONCLUSIONS

Our findings suggest that maternal leukocytes in PE show decreased anti-ferroptotic activity that correlates with anti-inflammatory expression. Moreover, some of these changes in ferroptotic activity appear to precede the development of PE.

Association of dietary inflammatory index with risk of gestational diabetes mellitus and preeclampsia: a systematic review and meta-analysis

Findings from observational studies have suggested a possible association between dietary inflammatory index (DII) and risk of gestational diabetes mellitus (GDM) and preeclampsia (PE). However, the results of these studies were inconclusive. A systematic review and meta-analysis was carried out to illuminate this association. Systematic literature search was conducted in PubMed, Web of Science, Cochrane Library, EMBASE, Scopus and other databases from inception until January 2023. The qualities of included studies were assessed using the Newcastle-Ottawa scale. Nine studies (seven cohort, two case-control) were included in the meta-analysis, including 11 423 participants from five different countries. The meta-analysis indicated that a 1-unit increase in the DII score, representing pro-inflammatory diet, was associated with 13 % higher risk of GDM (OR = 1·13; 95 % CI 1·02, 1·25, I2 = 68·4 %, P = 0·004) and 24 % higher risk of PE (OR = 1·24; 95 % CI 1·14, 1·35, I2 = 52·0 %, P = 0·125). Subgroup analysis found that this association was evident among studies with Chinese populations (OR = 1·16; 95 % CI 1·06, 1·28) and studies with mid pregnancy (OR = 1·20; 95 % CI 1·07, 1·34). The findings indicate that pro-inflammatory diet can increase the risk of GDM and PE. Considering some limitations in this study, more studies are needed to verify this association.

Biomarkers of Pre-eclampsia in Pregnant Women With Gestational Diabetes and Pre-existing Type 2 Diabetes: A Systematic Review

Pre-eclampsia (PE) is one of the leading causes of maternal and perinatal health morbidity, producing more than 4.6% of complications in pregnancy worldwide. This systematic review was conducted to determine the significance of specific biomarkers in predicting PE in gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (DM). The review measured and explained the significant abnormalities in lipids, blood glucose, cytokines, inflammatory markers, placental proteins, urinary proteins, and other serum biomarkers that contribute to the development of PE in GDM and type 2 DM populations. We searched CINAHL, EMBASE, Medline, Maternity and Infant care, Scopus, and Web of Science. Studies were included if they had a measurable component in the blood serum or urine of women who developed PE and suffered from GDM or pre-existing type 2 DM. A narrative synthesis was conducted instead of a meta-analysis due to the high heterogeneity of data from the studies. A total of 2,593 studies were screened, producing eight relevant studies. Twenty-seven different biomarkers were investigated from the study group of 40 to 1,344 participants. No single biomarker was identified; however, there is a need for further research on specific biomarkers of PE, especially in CRP, FABP4, and microalbuminuria in the GDM-PE group and calprotectin in the type 2 DM population. Many biomarkers were identified as practical in predicting PE when combined with other biomarkers and more data are required to verify the predictability of the diagnostic markers in pregnant women.

Downregulation of Salt-Inducible Kinase 3 Enhances CCL24 Activation in the Placental Environment with Preeclampsia

Preeclampsia (PE) remains one of the leading causes of maternal and perinatal morbidity and mortality. However, the exact pathophysiology of PE is still unclear. The recent widely accepted notion that successful pregnancy relies on maternal immunological adaptation is of utmost importance. Moreover, salt-inducible kinase 3 (SIK3) is an AMP-activated protein kinase-related kinase, and it has reported a novel regulator of energy and inflammation, and its expression related with some diseases. To explore whether SIK3 expression correlated with PE, we analyzed SIK3 gene expression and its association with PE through GEO datasets. We identified that SIK3 was significantly downregulated in PE across four datasets (p < 0.05), suggesting that SIK3 participated in the pathogenesis of PE. We initially demonstrated the significant downregulation of SIK3 in trophoblast cells of PE. SIK3 downregulation was positively correlated with the increased number of CD204(+) cells in in vivo and in vitro experiments. The increased number of CD204(+) cells could inhibit the migration and invasion of trophoblast cells. We then clarified the potential mechanism of PE with SIK3 downregulation: M2 skewing was triggered by trophoblast cells derived via the CCL24/CCR3 axis, leading to an increase in CD204(+) cells, a decrease in phagocytosis, and the production of IL-10 at the maternal-fetal interface of the placenta with PE. IL-10 further contributed to a reduction in the migration and invasion of trophoblast cells. It also established a feedback loop wherein trophoblast cells increased CCL24 production to maintain M2 dominance in the placental environments of PE.

Pro- and anti-inflammatory cytokines and growth factors in patients undergoing in vitro fertilization procedure treated with prednisone

Embryo implantation is a key moment in pregnancy. Abnormal production of pro- and anti-inflammatory cytokines, their receptors and other immune factors may result in embryo implantation failure and pregnancy loss. The aim of this study was to determine the profile of selected pro- and anti-inflammatory factors in the blood plasma of patients undergoing in vitro fertilization (IVF) and control women who achieved pregnancy after natural conception. The examined patients were administered steroid prednisone. We present results concern the plasma levels of IFN-ɣ, BDNF, LIF, VEGF-A, sTNFR1 and IL-10. We found that IVF patients receiving steroids differed significantly from patients who were not administered such treatment in terms of IFN-γ and IL-10 levels. Moreover, IVF patients differed in secretion of all tested factors with the fertile controls. Our results indicated that women who secrete at least 1409 pg/ml of sTNFR1 have a chance to become pregnant naturally and give birth to a child, while patients after IVF must achieve a concentration of 962.3 pg/ml sTNFR1 in blood plasma for successful pregnancy. In addition, IVF patients secreting VEGF-A above 43.28 pg/ml have a greater risk of miscarriage or a failed transfer in comparison to women secreting below this value. In conclusion, fertile women present a different profile of pro- and anti-inflammatory cytokines, and growth factors compared to patients with recurrent implantation failure (RIF).

Inflammatory markers are elevated in early pregnancy, but not late pregnancy, in women with overweight and obesity that later develop preeclampsia

PROBLEM

Obesity and preeclampsia both involve a pathological inflammatory response, which may be how obesity increases preeclampsia risk. Previous studies have failed to assess robust measurements of inflammatory markers across gestation, specifically in overweight/ obese women in the context of preeclampsia.

METHOD OF STUDY

We measured 20 inflammatory markers in plasma via multiplex assay (ThermoFisher Inflammation 20 plex Human ProcartaPlex Panel) across the three trimesters of pregnancy in an existing cohort of overweight and obese women who developed preeclampsia (n = 37) and without preeclampsia (n = 74). Mann-Whitney U tests examined differences in inflammatory marker concentrations between cases and controls. Repeated measures ANOVA tests were used to explore differences in inflammatory marker concentrations over time within cases and controls.

RESULTS

Pro-inflammatory markers (IL-1α, IL-1β, IL-6, IFN-α, IFN-γ, GM-CSF, IL-12p70, IL-17α, TNF-α, IL-8) and anti-inflammatory markers (IL-4, IL-10, IL-13) were higher in the first and second trimester in participants who later developed preeclampsia compared to those who did not (p < .05). Only TNF-α and IL-8 remained elevated in the third trimester. Inflammatory markers did not change across pregnancy in preeclampsia cases but did increase across pregnancy in controls.

CONCLUSION

Our findings diverge from prior studies, predominantly of non-obese women, that report lower circulating concentrations of anti-inflammatory cytokines in preeclampsia versus normotensive pregnancy, particularly by late pregnancy. We posit that women with overweight and obesity who develop preeclampsia entered pregnancy with a heightened pro-inflammatory state likely related to obesity, which increased risk for preeclampsia. Further studies are needed to investigate if inflammatory maker profiles differ between obese and non-obese women.

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.

Comprehensive Review of Hypertensive Disorders Related to Pregnancy

Hypertensive disorder of pregnancy is a common complication during pregnancy that affects approximately 10% of pregnancies and is responsible for nearly 14% of maternal deaths worldwide. It affects the mother and the fetus simultaneously, sometimes putting the health of the mother and the fetus at odds with each other. It may present with only hypertension and proteinuria or with life-threatening complications in the mother such as eclampsia; stroke; acute pulmonary edema; acute renal failure; disseminated intravascular coagulation; placental abruption; hemolysis, elevated liver enzymes, and low platelet syndrome; pregnancy loss; and fetal growth restriction and prematurity resulting from the frequent need of delivering preterm in the fetus. In this review, we aimed to describe hypertensive disorders of pregnancy, mainly preeclampsia and chronic hypertension in pregnancy, by discussing the pathophysiology, the central role of abnormal placentation, the release of antiangiogenic factors in the circulation and immunological factors, the clinical outcome in the mother and the fetus, and the diagnostic criteria and principles of management of both the conditions. We also discuss possible screening methods and prevention of preeclampsia using low-dose aspirin and eclampsia prophylaxis.

Dietary inflammatory index, inflammation biomarkers and preeclampsia risk: a hospital-based case-control study

This study evaluated the association between inflammatory diets as measured by the Dietary Inflammatory index (DII), inflammation biomarkers and the development of preeclampsia among the Chinese population. We followed the reporting guidelines of the Strengthening the Reporting of Observational Studies in Epidemiology statement for observational studies. A total of 466 preeclampsia cases aged over 18 years were recruited between March 2016 and June 2019, and 466 healthy controls were 1:1 ratio matched by age (±3 years), week of gestation (±1 week) and gestational diabetes mellitus. The energy-adjusted DII (E-DII) was computed based on dietary intake assessed using a seventy-nine item semiquantitative FFQ. Inflammatory biomarkers were analysed by ELISA kits. The mean E-DII scores were -0·65 ± 1·58 for cases and -1·19 ± 1·47 for controls (P value < 0·001). E-DII scores positively correlated with interferon-γ (r s = 0·194, P value = 0·001) and IL-4 (r s = 0·135, P value = 0·021). After multivariable adjustment, E-DII scores were positively related to preeclampsia risk (Ptrend < 0·001). The highest tertile of E-DII was 2·18 times the lowest tertiles (95 % CI = 1·52, 3·13). The odds of preeclampsia increased by 30 % (95 % CI = 18 %, 43 %, P value < 0·001) for each E-DII score increase. The preeclampsia risk was positively associated with IL-2 (OR = 1·07, 95 % CI = 1·03, 1·11), IL-4 (OR = 1·26, 95 % CI = 1·03, 1·54) and transforming growth factor beta (TGF-β) (OR = 1·17, 95 % CI = 1·06, 1·29). Therefore, proinflammatory diets, corresponding to higher IL-2, IL-4 and TGF-β levels, were associated with increased preeclampsia risk.

The human placenta shapes the phenotype of decidual macrophages

During human pregnancy, placenta-derived extravillous trophoblasts (EVTs) invade the decidua and communicate with maternal immune cells. The decidua distinguishes into basalis (decB) and parietalis (decP). The latter remains unaffected by EVT invasion. By defining a specific gating strategy, we report the accumulation of macrophages in decB. We describe a decidua basalis-associated macrophage (decBAM) population with a differential transcriptome and secretome compared with decidua parietalis-associated macrophages (decPAMs). decBAMs are CD11c^hi and efficient inducers of Tregs, proliferate in situ, and secrete high levels of CXCL1, CXCL5, M-CSF, and IL-10. In contrast, decPAMs exert a dendritic cell-like, motile phenotype characterized by induced expression of HLA class II molecules, enhanced phagocytosis, and the ability to activate T cells. Strikingly, EVT-conditioned media convert decPAMs into a decBAM phenotype. These findings assign distinct macrophage phenotypes to decidual areas depending on placentation and further highlight a critical role for EVTs in the induction of decB-associated macrophage polarization.

IL-10: A bridge between immune cells and metabolism during pregnancy

Energy metabolism plays a crucial role in the immune system. In addition to providing vital energy for cell growth, reproduction and other cell activities, the metabolism of nutrients such as glucose and lipids also have significant effects on cell function through metabolites, metabolic enzymes, and changing metabolic status. Interleukin-10 (IL-10), as a pleiotropic regulator, can be secreted by a diverse set of cells and can also participate in regulating the functions of various cells, thereby playing an essential role in the formation and maintenance of immune tolerance in pregnancy. Studies on the regulatory effects and mechanisms of IL-10 on immune cells are extensive; however, research from a metabolic perspective is relatively negligible. Here, we have discussed old and new data on the relationship between IL-10 and metabolism. The data show that alterations in cellular metabolism and specific metabolites regulate IL-10 production of immune cells. Moreover, IL-10 regulates immune cell phenotypes and functions by modulating oxidative phosphorylation and glycolysis. This review summarizes some earlier observations regarding IL-10 and its relationship with immune cells in pregnancy, and also presents recent research on the link between IL-10 and metabolism, highlighting the potential relationship between IL-10, immune cells, and energy metabolism during pregnancy.

The Complement System, T Cell Response, and Cytokine Shift in Normotensive versus Pre-Eclamptic and Lupus Pregnancy

Successful pregnancy requires an immunological shift with T helper CD4⁺ bias based on disbalance Th1/Th17 versus Th2/T regulatory (Tregs) required to induce tolerance against the semi-allogeneic fetus and placenta and to support fetal growth. Considered a pregnancy-specific hypertensive disorder, pre-eclampsia is characterized by multifaceted organ involvement related to impaired maternal immune tolerance to paternal antigens triggered by hypoxic placental injury as well as excessive local and systemic anti-angiogenic and inflammatory factor synthesis. Both systemic and local Th1/Th2 shift further expands to Th17 cells and their cytokines (IL-17) complemented by suppressive Treg and Th2 cytokines (IL-10, IL-4); alterations in Th17 and Tregs cause hypertension during pregnancy throughout vasoactive factors and endothelial dysfunction, providing an explanatory link between immunological and vascular events in the pathobiology of pre-eclamptic pregnancy. Apart from immunological changes representative of normotensive pregnancy, lupus pregnancy is generally defined by higher serum pro-inflammatory cytokines, lower Th2 polarization, defective and lower number of Tregs, potential blockade of complement inhibitors by anti-phospholipid antibodies, and similar immune alterations to those seen in pre-eclampsia. The current review underpins the immune mechanisms of pre-eclampsia focusing on local (placental) and systemic (maternal) aberrant adaptive and innate immune response versus normotensive pregnancy and pregnancy in systemic autoimmune conditions, particularly lupus.

SARS-CoV-2 and the Immune Response in Pregnancy with Delta Variant Considerations

As of September 2021, there has been a total of 123,633 confirmed cases of pregnant women with SARS-CoV-2 infection in the US according to the CDC, with maternal death being 2.85 times more likely, pre-eclampsia 1.33 times more likely, preterm birth 1.47 times more likely, still birth 2.84 times more likely, and NICU admission 4.89 times more likely when compared to pregnant women without COVID-19 infection. In our literature review, we have identified eight key changes in the immunological functioning of the pregnant body that may predispose the pregnant patient to both a greater susceptibility to SARS-CoV-2, as well as a more severe disease course. Factors that may impede immune clearance of SARS-CoV-2 include decreased levels of natural killer (NK) cells, Th1 CD4+ T cells, plasmacytoid dendritic cells (pDC), a decreased phagocytic index of neutrophil granulocytes and monocytes, as well as the immunomodulatory properties of progesterone, which is elevated in pregnancy. Factors that may exacerbate SARS-CoV-2 morbidity through hyperinflammatory states include increases in the complement system, which are linked to greater lung injury, as well as increases in TLR-1 and TLR-7, which are known to bind to the virus, leading to increased proinflammatory cytokines such as IL-6 and TNF-α, which are already elevated in normal pregnant physiology. Other considerations include an increase in angiotensin converting enzyme 2 (ACE2) in the maternal circulation, leading to increased viral binding on the host cell, as well as increased IL-6 and decreased regulatory T cells in pre-eclampsia. We also focus on how the Delta variant has had a concerning impact on SARS-CoV-2 cases in pregnancy, with an increased case volume and proportion of ICU admissions among the infected expecting mothers. We propose that the effects of the Delta variant are due to a combination of (1) the Delta variant itself being more transmissible, contagious, and efficient at infecting host cells, (2) initial evidence pointing to the Delta variant causing a significantly greater viral load that accumulates more rapidly in the respiratory system, (3) the pregnancy state being more susceptible to SARS-CoV-2 infection, as discussed in-depth, and (4) the lower rates of vaccination in pregnant women compared to the general population. In the face of continually evolving strains and the relatively low awareness of COVID-19 vaccination for pregnant women, it is imperative that we continue to push for global vaccine equity.

Different immunoregulatory components at the decidua basalis of oocyte donation pregnancies

Oocyte donation (OD) pregnancies are characterized by more fetal-maternal human leukocyte antigen (HLA) mismatches compared with naturally conceived (NC) and in vitro fertilization (IVF) pregnancies. The maternal immune system has to cope with greater immunogenetic dissimilarity, but involved immunoregulation remains poorly understood. We examined whether the amount of regulatory T cells (Tregs) and immunoregulatory cytokines in decidua basalis of OD pregnancies differs from NC and IVF pregnancies. The cohort included 25 OD, 11 IVF and 16 NC placentas, maternal peripheral blood, and umbilical cord blood of uncomplicated pregnancies. Placenta slides were stained for FOXP3, IL-10, IL-6, gal-1, TGF-β and Flt-1. Semi-quantitative (FOXP3+ Tregs) and computerized analysis (cytokines) were executed. The blood samples were typed for HLA class I and II to calculate fetal-maternal HLA mismatches. The percentage of Tregs was significantly higher in pregnancies with 4-6 HLA class I mismatches (n = 17), compared to 0-3 mismatches (n = 35; p = 0.04). Cytokine analysis showed significant differences between OD, IVF and NC pregnancies. Flt-1 was significantly lower in pregnancies with 4-6 HLA class I mismatches (p = 0.004), and in pregnancies with 6-10 HLA mismatches in total (p = 0.024). This study suggests that immunoregulation at the fetal-maternal interface in OD pregnancies with more fetal-maternal HLA mismatches is altered.

Defective Uteroplacental Vascular Remodeling in Preeclampsia: Key Molecular Factors Leading to Long Term Cardiovascular Disease

Preeclampsia is a complex hypertensive disorder in pregnancy which can be lethal and is responsible for more than 70,000 maternal deaths worldwide every year. Besides the higher risk of unfavorable obstetric outcomes in women with preeclampsia, another crucial aspect that needs to be considered is the association between preeclampsia and the postpartum cardiovascular health of the mother. Currently, preeclampsia is classified as one of the major risk factors of cardiovascular disease (CVD) in women, which doubles the risk of venous thromboembolic events, stroke, and ischemic heart disease. In order to comprehend the pathophysiology behind the linkage between preeclampsia and the development of postpartum CVD, a thorough understanding of the abnormal uteroplacental vascular remodeling in preeclampsia is essential. Therefore, this review aims to summarize the current knowledge of the defective process of spiral artery remodeling in preeclampsia and how the resulting placental damage leads to excessive angiogenic imbalance and systemic inflammation in long term CVD. Key molecular factors in the pathway-including novel findings of microRNAs-will be discussed with suggestions of future management strategies of preventing CVD in women with a history of preeclampsia.