The effects of advanced maternal age on T-cell subsets at the maternal-fetal interface prior to term labor and in the offspring: a mouse study

Exposure to gestational diabetes mellitus increases subclinical inflammation mediated in part by obesity

Gestational diabetes mellitus (GDM) is a frequent and serious complication of pregnancy, often associated with obesity. Metabolic dysfunction and metainflammation are evident in both obesity and GDM. In this cross-sectional study, we aimed at defining the direct contribution of the immune system in GDM, across the main metabolic tissues, specifically focussing on elucidating the roles of obesity and GDM to the clinical outcome. Using immunoassays and multicolour flow cytometry, cytokine profiles and immune cell frequencies were measured in maternal circulation and central metabolic tissues [placenta and visceral adipose tissue (VAT)] in GDM-diagnosed (n = 28) and normal glucose tolerant (n = 32) women undergoing caesarean section. Participants were sub-grouped as non-obese [body mass index (BMI) < 30 kg/m2] or obese (BMI ≥ 30 kg/m2). Unsupervised data analysis was performed on the flow cytometry data set to identify functional alterations. GDM obese participants had significantly elevated circulating IL-6 and IL-17A levels. GDM non-obese participants had elevated circulating IL-12p70, elevated placental IL-17A, and VAT IFN-γ production. Unsupervised clustering of immune populations across the three biological sites simultaneously, identified different NK- and T-cell phenotypes that were altered in NGT obese and GDM non-obese participants, while a classical tissue monocyte cluster was increased in GDM obese participants. In this study, there was significant evidence of subclinical inflammation, and significant alterations in clusters of NK cells, T cells, and tissue monocyte populations in GDM. While increased adiposity assimilates with increased inflammation in the non-pregnant state, this overt relationship may not be as evident during pregnancy and warrants further examination in future longitudinal studies.

Colonisation of Group B Streptococcus and its effects on pregnancy outcomes in pregnant women in Guangzhou, China: a retrospective study

OBJECTIVES

This study was to investigate the colonisation rate of Group B Streptococcus (GBS) during pregnancy, and to evaluate the influence of GBS colonisation on pregnancy outcomes.

DESIGN

A retrospective cohort study.

SETTING

Data of 47 380 pregnant women from 2016 to 2022 were collected from the Maternal and Child Health Hospital of Huadu District, Guangzhou City, China.

PARTICIPANTS

A total of 15 040 pregnant women were eligible for this study, of which 32 340 were excluded due to non-native pregnant women, in vitro fertilization infants, malformed fetuses, habitual abortion, abortions due to poor reproductive or obstetrical history, artificial insemination, umbilical cord torsion, and other diseases during pregnancy.

PRIMARY OUTCOME MEASURES

The incidence rates of GBS colonisation and premature delivery, fetal distress, premature rupture of membranes (PROM), low birth weight (LBW), abortion and stillbirth.

RESULTS

Of the 15 040 pregnant women included in this study, 1445 developed GBS colonisation, with a prevalence of 9.61% (95% CI, 9.15 to 10.09). Advanced maternal age (≥35 years) predisposed women to GBS colonisation, and the occurrence of GBS colonisation varied among different ethnic groups. Our data revealed that fetal distress, PROM and LBW were more common in pregnant women colonised with GBS than in pregnant women not colonised with GBS. The incidence for premature delivery, fetal distress, PROM and LBW in infants of pregnant women colonised with GBS was 41.0% (OR=1.410, 95% CI, 1.134 to 1.753), 282.5% (OR=3.825, 95% CI, 3.185 to 4.593), 14.9% (OR=1.149, 95% CI, 1.005 to 1.313), and 29.7% (OR=1.297, 95% CI, 1.010 to 1.664), respectively.

CONCLUSIONS

GBS colonisation was relatively low in pregnant women in Guangzhou. Women of advanced maternal age were more prone to GBS colonisation, and pregnant women colonised with GBS were more predisposed to fetal distress, PROM and LBW.

Embryonic factors mediate the maternal age-induced programming of offspring postnatal behavior in mice†

Advanced maternal age is associated with adverse pregnancy and offspring outcomes, including neurodevelopmental disorders. While age-related oocyte and embryonic abnormalities may underlie this association, the aged maternal uterine environment also plays an important role in offspring development and survival. The aim of this study was to evaluate the contribution of maternal age-related embryonic and uterine factors on pregnancy and offspring behavior, by using a model of reciprocal embryo transfer between old and young female mice. Pregnancies were obtained by transferring embryos collected from either old (9-14 months) or young (3-4 months) C57BL/6J female mice to either young or old recipients. The results showed that embryos from old and young donors have comparable developmental potential when transferred to young recipients, whereas no pregnancies were obtained by transferring embryos of young females to old recipients. Moreover, the offspring conceived by aged females displayed altered ultrasonic vocalization and learning skills compared to the progeny of young females, even though they were both prenatally and postnatally fostered by young recipients. These results indicate that maternal factors mostly determine the occurrence of age-related pregnancy complications, whereas the long-term effects of maternal aging on the offspring's behavior could be already established at pre-implantation stages and depend on embryonic factors.

The Associations of Maternal Health Characteristics, Newborn Metabolite Concentrations, and Child Body Mass Index among US Children in the ECHO Program

We aimed first to assess associations between maternal health characteristics and newborn metabolite concentrations and second to assess associations between metabolites associated with maternal health characteristics and child body mass index (BMI). This study included 3492 infants enrolled in three birth cohorts with linked newborn screening metabolic data. Maternal health characteristics were ascertained from questionnaires, birth certificates, and medical records. Child BMI was ascertained from medical records and study visits. We used multivariate analysis of variance, followed by multivariable linear/proportional odds regression, to determine maternal health characteristic-newborn metabolite associations. Significant associations were found in discovery and replication cohorts of higher pre-pregnancy BMI with increased C0 and higher maternal age at delivery with increased C2 (C0: discovery: aβ 0.05 [95% CI 0.03, 0.07]; replication: aβ 0.04 [95% CI 0.006, 0.06]; C2: discovery: aβ 0.04 [95% CI 0.003, 0.08]; replication: aβ 0.04 [95% CI 0.02, 0.07]). Social Vulnerability Index, insurance, and residence were also associated with metabolite concentrations in a discovery cohort. Associations between metabolites associated with maternal health characteristics and child BMI were modified from 1-3 years (interaction: p < 0.05). These findings may provide insights on potential biologic pathways through which maternal health characteristics may impact fetal metabolic programming and child growth patterns.

Parental Programming of Offspring Health: The Intricate Interplay between Diet, Environment, Reproduction and Development

As adults, our health can be influenced by a range of lifestyle and environmental factors, increasing the risk for developing a series of non-communicable diseases such as type 2 diabetes, heart disease and obesity. Over the past few decades, our understanding of how our adult health can be shaped by events occurring before birth has developed into a well-supported concept, the Developmental Origins of Health and Disease (DOHaD). Supported by epidemiological data and experimental studies, specific mechanisms have been defined linking environmental perturbations, disrupted fetal and neonatal development and adult ill-health. Originally, such studies focused on the significance of poor maternal health during pregnancy. However, the role of the father in directing the development and well-being of his offspring has come into recent focus. Whereas these studies identify the individual role of each parent in shaping the long-term health of their offspring, few studies have explored the combined influences of both parents on offspring well-being. Such understanding is necessary as parental influences on offspring development extend beyond the direct genetic contributions from the sperm and oocyte. This article reviews our current understanding of the parental contribution to offspring health, exploring some of the mechanisms linking parental well-being with gamete quality, embryo development and offspring health.

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.

Delayed parenthood and its influence on offspring health: What have we learned from the mouse model

Delayed parenthood is constantly increasing worldwide due to various socio-economic factors. In the last decade, a growing number of epidemiological studies have suggested a link between advanced parental age and an increased risk of diseases in the offspring. Also, poor reproductive outcome has been described in pregnancies conceived by aged parents. Similarly, animal studies showed that aging negatively affects gametes, early embryonic development, pregnancy progression and the postnatal phenotype of resulting offspring. However, how and to what extent parental age is a risk factor for the health of future generations is still subject to debate. Notwithstanding the limitation of an animal model, the mouse model represents a useful tool to understand not only the influence of parental age on offspring phenotype but also the biological mechanisms underlying the poor reproductive outcome and the occurrence of diseases in the descendants. The present review aims at i) providing an overview of the current knowledge from mouse model about the risks associated with conception at advanced age (e.g. neurodevelopmental and metabolic disorders), ii) highlighting the candidate biological mechanisms underlying this phenomenon, and iii) discussing on how murine-derived data can be relevant to humans.

Maternal and fetal T cells in term pregnancy and preterm labor

Pregnancy is a state of immunological balance during which the mother and the developing fetus must tolerate each other while maintaining sufficient immunocompetence to ward off potential threats. The site of closest contact between the mother and fetus is the decidua, which represents the maternal-fetal interface. Many of the immune cell subsets present at the maternal-fetal interface have been well described; however, the importance of the maternal T cells in this compartment during late gestation and its complications, such as preterm labor and birth, has only recently been established. Moreover, pioneer and recent studies have indicated that fetal T cells are activated in different subsets of preterm labor and may elicit distinct inflammatory responses in the amniotic cavity, leading to preterm birth. In this review, we describe the established and proposed roles for maternal T cells at the maternal-fetal interface in normal term parturition, as well as the demonstrated contributions of such cells to the pathological process of preterm labor and birth. We also summarize the current knowledge of and proposed roles for fetal T cells in the pathophysiology of the preterm labor syndrome. It is our hope that this review provides a solid conceptual framework highlighting the importance of maternal and fetal T cells in late gestation and catalyzes new research questions that can further scientific understanding of these cells and their role in preterm labor and birth, the leading cause of neonatal mortality and morbidity worldwide.