Interleukin-22: biomarker of maternal and fetal inflammation?

Deciduous tooth biomarkers reveal atypical fetal inflammatory regulation in autism spectrum disorder

Atypical regulation of inflammation has been proposed in the etiology of autism spectrum disorder (ASD); however, measuring the temporal profile of fetal inflammation associated with future ASD diagnosis has not been possible. Here, we present a method to generate approximately daily profiles of prenatal and early childhood inflammation as measured by developmentally archived C-reactive protein (CRP) in incremental layers of deciduous tooth dentin. In our discovery population, a group of Swedish twins, we found heightened inflammation in the third trimester in children with future ASD diagnosis relative to controls (n = 66; 14 ASD cases; critical window: -90 to -50 days before birth). In our replication study, in the US, we observed a similar increase in CRP in ASD cases during the third trimester (n = 47; 23 ASD cases; -128 to -21 days before birth). Our results indicate that the third trimester is a critical period of atypical fetal inflammatory regulation in ASD.

Cellular mechanisms linking to outdoor and indoor air pollution damage during pregnancy

Pregnancies are a critical window period for environmental influences over the mother and the offspring. There is a growing body of evidence associating indoor and outdoor air pollution exposure to adverse pregnancy outcomes such as preterm birth and hypertensive disorders of pregnancy. Particulate matter (PM) could trigger oxi-inflammation and could also reach the placenta leading to placental damage with fetal consequences. The combination of strategies such as risk assessment, advise about risks of environmental exposures to pregnant women, together with nutritional strategies and digital solutions to monitor air quality can be effective in mitigating the effects of air pollution during pregnancy.

Cytokine-polymorphisms associated with Preeclampsia: A review

BACKGROUND

Preeclampsia (PE) is a syndromic disorder that affects 2% to 8% of pregnancies and is diagnosed principally when hypertension appears in the second-d half of pregnancy. WHO estimates the incidence of PE to be seven times higher in developing countries than in developed countries. Severe preeclampsia/eclampsia is one of the most important causes of maternal mortality, associated with 50,000 to 100,000 annual deaths globally as well as serious fetal and neonatal morbidity and mortality, especially in developing countries. Even though evidence from family-based studies suggest PE has a heritable component, its etiology, and specific genetic contributions remain unclear. Many studies examining the genetic factors contributing to PE have been conducted, most of them are focused on single nucleotide polymorphisms (SNPs). Given that PE has a very important inflammatory component, is mandatory to examine cytokine-SNPs for elucidating all mechanisms involved in this pathology. In this review, we describe the most important cytokine-polymorphisms associated with the onset and development of PE. We aim to provide current and relevant evidence in this regard.

METHODS

We searched English databases such as PubMed and the National Center for Biotechnology Information. The publication time of the papers was set from the establishment of the databases to February 2022. All studies about Th1/Th2/Th17 cytokines polymorphisms were included in our study.

RESULTS

SNPs in IFN-γ, TNF-α, IL-4, IL-6, IL-10, IL-17A, and IL-22 are associated with the development, early-onset and severity of PE, being the Th1/Th2/Th17 responses affected by the presence of these SNPs.

CONCLUSIONS

The changes in Th1/Th2/Th17 response modify processes such as placentation, control of inflammation, and vascular function. Nonetheless, association studies have shown different results depending on sample size, diagnostic, and population.

The Implication of Aquaporin-9 in the Pathogenesis of Preterm Premature Rupture of Membranes

OBJECTIVE

This study aimed to detect aquaporin-9 (AQP9) concentrations in the serum of patients with preterm premature rupture of membranes (PPROM) and compare them with the healthy control group with intact membranes.

MATERIAL AND METHODS

We conducted this prospective case-control study from January 2020 to June 2020. Of the 80 pregnant patients included in the study, we enrolled 42 singleton pregnant patients with PPROM as the study group and 43 healthy gestational age-, and body mass index (BMI)-matched healthy pregnant women with intact fetal membranes as the control group. We compared demographic and clinical characteristics, complete blood count and biochemical parameters, and serum AQP9 concentrations of the participants. We constructed an ROC curve to illustrate the sensitivity and specificity performance characteristics of AQP9 and calculated a cutoff value by using the Youden index.

RESULTS

Maternal serum AQP-9 concentrations were significantly higher in patients with PPROM (804.46±195.63 pg/mL) compared to the healthy pregnant women in the control group (505.97±68.89 pg/mL, p<0.001). When we examine the area under the ROC curve (AUC), the AQP-9 value can be reflected as a statistically significant parameter for diagnosing PPROM. According to the Youden index, a 654.78 pg/mL cut-off value of AQP-9 can be utilized to diagnose PPROM with 80.5% sensitivity and 100% specificity.

CONCLUSION

Maternal serum AQP9 concentrations were significantly higher in PPROM patients than healthy pregnant women with an intact membrane. We suggest that AQP9 might be an essential biomarker of the inflammatory process and energy homeostasis in PPROM.

IL-22 Plays a Dual Role in the Amniotic Cavity: Tissue Injury and Host Defense against Microbes in Preterm Labor

IL-22 is a multifaceted cytokine with both pro- and anti-inflammatory functions that is implicated in multiple pathologies. However, the role of IL-22 in maternal-fetal immunity in late gestation is poorly understood. In this study, we first showed that IL-22+ T cells coexpressing retinoic acid-related orphan receptor γt (ROR-γt) are enriched at the human maternal-fetal interface of women with preterm labor and birth, which was confirmed by in silico analysis of single-cell RNA sequencing data. T cell activation leading to preterm birth in mice was preceded by a surge in IL-22 in the maternal circulation and amniotic cavity; however, systemic administration of IL-22 in mice did not induce adverse perinatal outcomes. Next, using an ex vivo human system, we showed that IL-22 can cross from the choriodecidua to the intra-amniotic space, where its receptors (Il22ra1, Il10rb, and Il22ra2) are highly expressed by murine gestational and fetal tissues in late pregnancy. Importantly, amniotic fluid concentrations of IL-22 were elevated in women with sterile or microbial intra-amniotic inflammation, suggesting a dual role for this cytokine. The intra-amniotic administration of IL-22 alone shortened gestation and caused neonatal death in mice, with the latter outcome involving lung maturation and inflammation. IL-22 plays a role in host response by participating in the intra-amniotic inflammatory milieu preceding Ureaplasma parvum-induced preterm birth in mice, which was rescued by the deficiency of IL-22. Collectively, these data show that IL-22 alone is capable of causing fetal injury leading to neonatal death and can participate in host defense against microbial invasion of the amniotic cavity leading to preterm labor and birth.

Regulatory T Cells Play a Role in a Subset of Idiopathic Preterm Labor/Birth and Adverse Neonatal Outcomes

Regulatory T cells (Tregs) have been exhaustively investigated during early pregnancy; however, their role later in gestation is poorly understood. Herein, we report that functional Tregs are reduced at the maternal-fetal interface in a subset of women with idiopathic preterm labor/birth, which is accompanied by a concomitant increase in Tc17 cells. In mice, depletion of functional Tregs during late gestation induces preterm birth and adverse neonatal outcomes, which are rescued by the adoptive transfer of such cells. Treg depletion does not alter obstetrical parameters in the mother, yet it increases susceptibility to endotoxin-induced preterm birth. The mechanisms whereby depletion of Tregs induces adverse perinatal outcomes involve tissue-specific immune responses and mild systemic maternal inflammation, together with dysregulation of developmental and cellular processes in the placenta, in the absence of intra-amniotic inflammation. These findings provide mechanistic evidence supporting a role for Tregs in the pathophysiology of idiopathic preterm labor/birth and adverse neonatal outcomes.

Impact of chorioamnionitis on maternal and fetal levels of proinflammatory S100A12

Histologic chorioamnionitis (HCA) may lead to the fetal inflammatory response syndrome (FIRS). The aim of this pilot study was to evaluate S100A12, a marker of innate immune activation, in mothers with or without HCA and in their infants. Concentrations of S100A12, interleukin 6 (IL-6), and C-reactive protein (CRP) were evaluated in maternal, cord, and neonatal blood of very preterm infants. Histologic examinations of the placenta and umbilical cords were performed. The 48 mother-neonate pairs enrolled were subdivided into two groups: HCA group (N = 15) and control group without HCA (N = 33). Maternal S100A12 levels were similar between HCA and control group. Similarly, S100A12 concentrations in cord and neonatal blood did not differ between the groups. However, high S100A12 concentrations were detected in cord and neonatal blood of two out of three neonates exposed to HCA associated with advanced funisitis. Concentrations of IL-6 and CRP were higher in maternal blood of the HCA group compared with controls (p < 0.05, p < 0.001; respectively), but no differences in cord or neonatal blood was found.Conclusion:S100A12 did neither identify mothers with HCA nor very preterm infants exposed to HCA. It is currently unknown if S100A12 may identify neonates with FIRS. What is known: • Histologic chorioamnionitis (HCA) may lead to the fetal inflammatory response syndrome (FIRS). • S100A12 represents an early, sensitive, and specific diagnostic marker of inflammatory processes. What is new: • S100A12 did neither identify mothers with HCA nor very preterm infants exposed to HCA. • It is currently still unclear if S100A12 has a potential in identifying preterm infants with FIRS.

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

A key immunomodulatory cytokine, IL-10 (interleukin-10), has been shown to be dysregulated in preeclampsia, a pregnancy-specific hypertensive disorder, further characterized by multi-system involvement. However, studies have reported inconsistent findings about circulating IL-10 levels in preeclamptic versus normotensive pregnancies. The aim of the present systematic review and meta-analysis was to assess circulating IL-10 levels in preeclamptic and normotensive pregnancies at 2 time points: before, and at the time of preeclampsia diagnosis. PubMED, EMBASE, and Web of Science databases were searched to include all published studies examining circulating IL-10 levels in preeclamptic and normotensive pregnancies. Differences in IL-10 levels were evaluated by standardized mean differences. Of 876 abstracts screened, 56 studies were included in the meta-analysis. Circulating IL-10 levels were not different before the time of active disease (standardized mean differences, -0.01 [95% CI, -0.11 to 0.08]; P=0.76). At the time of active disease, women with preeclampsia (n=1599) had significantly lower IL-10 levels compared with normotensive controls (n=1998; standardized mean differences, -0.79 [95% CI, -1.22 to -0.35]; P=0.0004). IL-10 levels were lower in both early/severe and late/mild forms of preeclampsia. Subgroup analysis revealed that IL-10 measurement methodology (ELISA or multiplex bead array) and the sample type (plasma or serum) significantly influenced the observed differences, with the use of sera paired with ELISA technology providing the best distinction in IL-10 levels between preeclamptic and normotensive pregnancies. These findings support the role of decreased IL-10 levels in the pathophysiology of preeclampsia. Future studies should address the therapeutic potential of IL-10 in preeclampsia.

Early predictors of small-for-gestational-age neonates using non-invasive, low-cost, and readily available hematological markers

OBJECTIVE

To evaluate whether neutrophil-to-lymphocyte ratio (NLR), a well-established inflammatory marker, can be used as an early predictor for small-for-gestational-age (SGA) neonates and other adverse pregnancy outcomes.

METHODS

A case-control study compared first-trimester hematological biomarkers in pregnancies of patients with and without SGA (n=149, n=151, respectively). Demographic, clinical, and obstetrical characteristics and first-trimester complete blood count were retrieved. Woman with singleton pregnancies who delivered at Soroka University Medical Center between January 2015 and December 2016 were included. Patients with known maternal infections, relevant medications, hematological conditions, and chronic diseases that may alter the blood count, those with multiple pregnancies, and those with congenital or chromosomal abnormalities were excluded. After univariate analysis, a linear regression model was constructed to assess the association between hematological indices and SGA. Receiver operating curves were constructed to evaluate the sensitivity and specificity of NLR.

RESULTS

First-trimester NLR values of the SGA group were significantly higher compared to controls (3.03 ± 1.68 vs 2.63 ± 1.2, P=0.016). Significantly higher levels of NLR were noted among the severely (<3%) SGA neonates (3.12 ± 1.62 vs 2.62 ± 1.2; P=0.034).

CONCLUSION

NLR may be an early, clinically useful marker in the prediction of SGA. As blood samples are routinely collected, correct implication of this result may serve as a valuable non-invasive, low-cost, readily available predicting tool.

Circulating levels of IFN-γ, IL-1, IL-17 and IL-22 in pre-eclampsia: A systematic review and meta-analysis

OBJECTIVE

Pre-eclampsia (PE) is a common multi-systemic disease, and the effect of cytokines on PE is not clear. The purpose of this meta-analysis was to evaluate the circulating levels of interferon gamma (IFN-γ), interleukin (IL)-1, IL-17 and IL-22 in patients with PE.

STUDY DESIGN

Relevant studies were identified after a preliminary investigation of studies published up to May 2019 using PubMed and Embase. In this study, all 27 included articles underwent quality rating, with a total of 495 patients with PE and 557 controls. Among them, eight papers and 932 subjects contributed to the meta-analysis of IFN-γ, and six papers and 343 subjects contributed to the meta-analysis of IL-17. Based on the inclusion and exclusion criteria, the retrieved papers were screened and evaluated independently. Relevant data for IFN-γ and IL-17 were extracted for meta-analysis and subgroup analysis, and the stability of the results was evaluated by sensitivity analysis. At the same time, a systematic evaluation was carried out for IL-1 and IL-22 with a small number of included papers.

RESULTS

Several papers included in the systematic review showed that the circulating levels of IL-22 were higher in patients with severe PE than in controls, while IL-1 levels did not differ significantly between the two groups. The meta-analysis showed that patients with PE had higher circulating levels of IFN-γ than controls [standardized mean difference (SMD) 1.45, 95 % confidence interval (CI) 0.56-2.34]. There was no evidence of a difference in the circulating levels of IL-17 between patients with PE and controls (SMD 0.53, 95 %CI -0.43 to 1.48).

CONCLUSION

This meta-analysis suggested that changes in circulating levels of IFN-γ might be associated with PE.

Haplotype Analysis of Candidate Genes Involved in Inflammation and Oxidative Stress and the Susceptibility to Preeclampsia

Unbalanced inflammatory reactions and oxidative stress are inseparably interconnected, and both may play crucial roles in the pathophysiological mechanisms of preeclampsia (PE). In the published previous studies, we have genotyped for SNPs that related to inflammation (rs2227485, rs153109, rs17855750, rs2027432, rs2275913, rs763780, rs4819554, and rs13015714) and oxidative stress (rs1695, rs4680, rs1800566, rs4807542, rs713041, rs7579, rs230813, rs1004467, rs3824755, and rs9932581) to investigate whether these polymorphisms were associated with susceptibility to PE in a Chinese Han population. In this present study, we collected these data of experimental and clinical from above studies for haplotype analysis of inflammation-related SNPs in 631 PE patients and 720 normal pregnancy and oxidative stress-related SNPs in 342 PE patients and 457 normal pregnancies for susceptibility to PE. The data of genotype distribution and allele frequency comparisons after correction for multiple comparisons (P/8 or P/10) showed 2 among the 8 candidate inflammation-related SNPs have significant differences (rs2027432 genotype χ² = 407.377, p < 0.001, p < 0.00625). Moreover, the minor alleles of rs2027432 T (minor allele χ² = 450.923, p < 0.001, p < 0.00625; OR = 21.439, 95%CI = 15.181‐30.278) and rs4819554 G (minor allele χ² = 163.465, p < 0.001, p < 0.00625; OR = 5.814, 95%CI = 4.380‐7.719) were confirmed as risk allele of PE, respectively. Our analysis revealed rs2027432 (TT) of NLRP3 and rs4819554 (GG) of IL-17RA are risk factors for PE. However, no significant difference was found at the oxidative stress-related SNPs. In the candidate loci for oxidative stress, we also identified 3 SNP matches (rs4807542 and rs713041, rs230813 and rs75799, rs1004467 and rs3824755) that had high linkage disequilibrium (LD) with each other and were selected as a block (r² = 0.98, r² = 0.97, r² = 0.97, r² > 0.9), and the GT and GC haplotypes of rs4807542 and rs713041 in GPX4 showed significant differences between the PE and control groups (χ² = 5.143, p = 0.0233, p < 0.05; χ² = 6.373, p = 0.0116, p < 0.05). So, we inferred that polymorphisms of NLRP3 rs2027432 and IL-17RA rs4819554, which are related to inflammation, and the rs713041 variant of GPX4, which is related to oxidative stress, were associated with susceptibility to PE. The GT and GC haplotypes of rs4807542 and rs713041 in GPX4 may increase the risk of PE in the Chinese Han population.

[Maternal neutrophil-to-lymphocyte ratio as a prognostic biomarker for placental inflammatory response in late pregnancy]

OBJECTIVE

To investigate the association between maternal serum neutrophil-lymphocyte ratio (NLR) and placental inflammatory response (PIR) in late pregnancy.

METHODS

We retrospectively analyzed the clinical and follow-up data of 478 pregnant women undergoing routine prenatal examination and delivery in our hospital in the year 2016. According to the placental pathological results, the women were divided into PIR group (238 cases) and control group (240 cases). The levels of serum inflammatory makers including leukocytes, neutrophils, lymphocytes, C-reactive protein (CRP) and NLR were compared between the two groups to analyze the association of these markers with PIR. Multivariate analysis was performed to identify the independent risk factors of PIR. Logistic regression model was established and the area under the receiver operating characteristic curve (ROC) was used for analyzing the prognostic value of these makers in late pregnancy.

RESULTS

The areas under the curve (AUC) of leukocytes, neutrophils, lymphocytes, CRP and NLR were 0.698 (95%CI: 0.485-0.766), 0.716 (95%CI: 0.453-0.783), 0.329 (95%CI: 0.228-0.431), 0.725 (95%CI: 0.677-0.765) and 0.801 (95%CI: 0.742-0.856), respectively. After adjusting the confounders, multivariate logistic regression analysis showed that preterm labor (OR=2.446, 95%CI: 1.003-4.590), premature rupture of membranes (OR=2.304, 95%CI: 1.049-4.161), NLR &gt; 7 (OR=3.268, 95%CI: 2.071-6.920), and CRP &gt; 15 mg/L (OR=2.137, 95%CI: 1.412-8.236) were independent risk factors for PIR.

CONCLUSIONS

An increased NLR in late pregnancy can serve as an effective indicator for predicting the risk of PIR.

The role of interleukins in preeclampsia: A comprehensive review

Preeclampsia is a multi-system hypertensive disorder of pregnancy, with significant rates of maternal and neonatal morbidity. It represents a major cause of preterm birth, as definitive treatment demands fetal delivery. Although its pathophysiology is complicated, placental hypoxia and endothelial dysfunction constitute established pathogenetic steps of the disease. Inflammation is considered to be a crucial mediator of preeclampsia process, as an imbalance between T_H 1, T_H 2, and T_H 17 immune responses is observed. The present review accumulates current knowledge about the contribution of interleukins in preeclampsia, summarizing the pathways through which each interleukin exerts its function in the disease. Also, the role of genetic polymorphisms is explored and the predictive efficacy of maternal serum interleukin levels is evaluated. Finally, recommendations about the safe interpretation of the outcomes, as well as guidance for future research, are provided.

Impact of IL-22 and IL-22 receptor alpha 1 polymorphisms on preeclampsia risk in Chinese Han women

Previous studies have indicated that an increased inflammatory response plays an important role in preeclampsia (PE), and rising levels of interleukin (IL)-22 can trigger inflammation and hyperproliferation, leading to increased production of several pro-inflammatory cytokines such as IL-1, IL-6, and IL-8. We aimed to investigate the association between polymorphisms of IL-22 and IL-22 receptor alpha 1 gene (IL-22RA1) and PE in Chinese Han population. Single nucleotide polymorphisms (SNPs) rs2227485 in IL-22 and rs3795299 in IL-22RA were genotyped by Taqman real-time PCR in 1071 PE patients and 1263 control subjects. Differences in genetic distribution were compared between two groups using the chi-square test. Significant differences were observed in genotypic and allelic frequencies of IL-22RA1 rs3795299 between healthy controls and PE patients (P < 0.001 by genotype; P = 0.001, odds ratio = 1.253, 95% confidence interval 1.103-1.424 by allele). There were also significant differences in genotypic and allelic frequencies of rs3795299 between late-onset/mild PE and control groups. In addition, we found obvious statistic difference for the allele of early-onset PE/the genotype of late-onset PE and control subgroups for IL-22 rs2227485. IL-22 rs2227485 and IL-22RA1 rs3795299 may be associated with the development of PE in Chinese Han population. However, further validation is required in other populations, as well as an evaluation of the association of other SNPs in IL-22 and IL-22RA1 with PE.

Synthetic PreImplantation Factor (PIF) prevents fetal loss by modulating LPS induced inflammatory response

Maternal control of inflammation is essential during pregnancy and an exaggerated response is one of the underlying causes of fetal loss. Inflammatory response is mediated by multiple factors and Toll-like receptors (TLRs) are central. Activation of TLRs results in NALP-3 mediated assembly of apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1 into the inflammasome and production of pro-inflammatory cytokines IL-1β and IL-18. Given that preventing measures are lacking, we investigated PreImplantation Factor (PIF) as therapeutic option as PIF modulates Inflammation in pregnancy. Additionally, synthetic PIF (PIF analog) protects against multiple immune disorders. We used a LPS induced murine model of fetal loss and synthetic PIF reduced this fetal loss and increased the embryo weight significantly. We detected increased PIF expression in the placentae after LPS insult. The LPS induced serum and placenta cytokines were abolished by synthetic PIF treatment and importantly synthetic PIF modulated key members of inflammasome complex NALP-3, ASC, and caspase-1 as well. In conclusion our results indicate that synthetic PIF protects against LPS induced fetal loss, likely through modulation of inflammatory response especially the inflammasome complex. Given that synthetic PIF is currently tested in autoimmune diseases of non-pregnant subjects (clinicaltrials.gov, NCT02239562), therapeutic approach during pregnancy can be envisioned.

Correlations of maternal neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) with birth weight

OBJECTIVE

The aim of this study is to investigate the possible correlation of hemogram parameters including neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) with birth weight and gestational week.

MATERIALS AND METHODS

This prospective study has been conducted with 783 patients. The maternal age, parity, gestational age, type of delivery, values of complete blood count (CBC) variables and the weight of newborn were recorded. We analyzed the statistical differences between the NLR, PLR, hemoglobin (HGB), platelet distribution width (PDW), red cell distribution width (RDW), mean platelet volume (MPV), platelet, neutrophil, lymphocyte and white blood cells (WBC) in terms of the birth weight.

RESULTS

There was no statistically significant difference in the NLR in terms of the birth weight (p = 0.097), whereas there was a statistically significant difference in the PLR (p < 0.001). In correlation analyses, a linear, negative, weak and statistically significant correlation was detected between NLR and PLR with the birth weight of infant and gestational week (p = 0.011 and p < 0.001, respectively).

CONCLUSION

This prospective study is the first in the literature which investigates the correlation of NLR and PLR with the week of birth and birth weight of the infant. Our study suggested that the maternal NLR and PLR are negatively correlated with the week of birth and birth weight of the infant.