Sex-Specific Placental Responses in Fetal Development

Brominated flame retardants and legacy organochlorines in archived human placenta samples: Sex differences, temporal analysis and associations with infant birth weight

Perinatal exposure to persistent organic pollutants (POPs) has been suggested to play a role in the etiology of adverse pregnancy outcomes. This study evaluated temporal changes in the accumulation of several classes of POPs, including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and several organochlorine pesticides in human placenta and examined their associations with birth outcomes at delivery. Placental tissues (n = 99) previously collected and archived at the Duke University Medical Center from 2009 to 2015 were analyzed for 22 POPs using gas chromatography mass spectrometry. The mean age of mothers was 30.6 years; 8% of newborns were characterized as low birthweight (<2500 g). Of the 22 POPs targeted in the analysis, only p,p'-DDE, BDE-47 and BDE-100 were detected in more than 50% of the samples, with median concentrations of 0.110, 0.310, and 0.033 ng/g wet weight, respectively. Placental PBDE concentrations generally decreased over time, particularly BDE-47. Placental tissues associated with female infants had significantly higher levels of BDE-100 than placental tissues associated with male infants (p = 0.02) and a similar, but not statistically significant trend was observed for BDE-47 (p = 0.07). Multivariate regression models revealed that placental BDE-47 concentrations were associated with a significantly lower birthweight among male, but not female infants. A similar, although non-statistically significant, trend was observed for other POPs, further suggesting sex-specific associations between gestational exposure to POPs and birthweight.

Fetal sex and the development of gestational diabetes mellitus in polycystic ovarian syndrome gravidae

BACKGROUND

Polycystic ovarian syndrome is characterized by elevated androgens and is a well-known risk factor for the occurrence of gestational diabetes mellitus. Androgens (particularly dehydroepiandrosterone-sulfate) are crucial for the development and characteristics of the male reproductive tract during fetal life, and fetal dehydroepiandrosterone-sulfate enters the placenta where it is metabolized and functions as an estrogen substrate. Given this unique sex-specific relationship with androgens and the association of serum dehydroepiandrosterone-sulfate concentration with insulin resistance, we hypothesized that metabolic comorbidities in pregnancy might differ by fetal sex in gravidae with polycystic ovarian syndrome, notably in those with infertility.

OBJECTIVE

This study aimed to evaluate the data in a large population-based database to explore if fetal sex was significantly associated with gestational diabetes mellitus in gravidae with infertility and polycystic ovarian syndrome after controlling for confounders.

STUDY DESIGN

This study was designed to evaluate the risk for the occurrence and rates of gestational diabetes mellitus among gravidae with infertility and a history of polycystic ovarian syndrome. We used a 2-hospital, single academic institution database comprising more than 30,000 subjects enrolled from September 2011 to June 2021 to identify all gravidae with diagnoses of infertility and polycystic ovarian syndrome at the time of delivery and to compare them with gravidae who lacked these comorbidities. Data on covariates, including but not limited to maternal age, body mass index, fetal sex, race, ethnicity, presence or absence of hypertensive disease, and presence or absence of gestational diabetes were identified. Unadjusted and adjusted odds rations were calculated.

RESULTS

We found a statistically significant association between fetal female sex and the development of gestational diabetes mellitus in gravidae with polycystic ovarian syndrome (odds ratio for female vs male, 2.13; 95% confidence interval, 1.06-4.32; P=.03). After adjusting for potential confounders identified in our univariate analyses, there continued to be a statistically significant association between female fetuses and the development of gestational diabetes mellitus (adjusted odds ratio for female vs male, 2.10; 95% confidence interval, 1.04-4.41; P=.04). In contrast, there was no significant association between fetal sex and the development of gestational diabetes mellitus in our similar analysis of gravidae without infertility and polycystic ovarian syndrome (P=.99).

CONCLUSION

Although the origin of gestational diabetes mellitus is multifactorial, we found that female fetal sex is associated with gestational diabetes mellitus in gravidae with infertility and polycystic ovarian syndrome but not in their comparative controls. Further research on the molecular mechanisms driving the association between female fetuses and the development of gestational diabetes mellitus in the context of maternal polycystic ovarian syndrome is warranted.

Maternal urinary bisphenols and phthalates in relation to estimated fetal weight across mid to late pregnancy

BACKGROUND

Bisphenols and phthalates are high production volume chemicals used as additives in a variety of plastic consumer products leading to near ubiquitous human exposure. These chemicals have established endocrine disrupting properties and have been linked to a range of adverse reproductive and developmental outcomes. Here, we investigated exposure in relation to fetal growth.

METHODS

Participants included 855 mother-fetal pairs enrolled in the population-based New York University Children's Health and Environment Study (NYU CHES). Bisphenols and phthalates were measured in maternal urine collected repeatedly during pregnancy. Analyses included 15 phthalate metabolites and 2 bisphenols that were detected in 50 % of participants or more. Fetal biometry data were extracted from electronic ultrasonography records and estimated fetal weight (EFW) was predicted for all fetuses at 20, 30, and 36 weeks gestation. We used quantile regression adjusted for covariates to model exposure-outcome relations across percentiles of fetal weight at each gestational timepoint. We examined sex differences using stratified models.

RESULTS

Few statistically significant associations were observed across chemicals, gestational time periods, percentiles, and sexes. However, within gestational timepoints, we found that among females, the molar sums of the phthalates DiNP and DnOP were generally associated with decreases in EFW among smaller babies and increases in EFW among larger babies. Among males, the opposite trend was observed. However, confidence intervals were generally wide at the tails of the distribution.

CONCLUSION

In this sample, exposure to bisphenols and phthalates was associated with small sex-specific shifts in fetal growth; however, few associations were observed at the median of fetal weight and confidence intervals in the tails were wide. Findings were strongest for DiNP and DnOP, which are increasingly used as replacements for DEHP, supporting the need for future research on these contaminants.

The Effect of Tobacco Use on the Expression of Placental Transporters in Alaska Native Women

Prenatal tobacco use among Alaska Native (AN) women has decreased substantially over the past two decades. Previous research suggests that providing AN women with feedback regarding fetal exposure to tobacco may further promote cessation. Transporters in the placenta regulate fetal exposure to nutrients and xenobiotics, including compounds associated with tobacco use. We examined whether prenatal tobacco use impacts transporter expression in the placenta, and whether this is influenced by fetal sex, degree of tobacco exposure, or transporter genotype. At delivery, we obtained placental samples from AN research participants who smoked cigarettes, used commercial chew or iqmik (oral tobacco), or did not use tobacco during pregnancy. Transporter expression was evaluated using qRT-PCR and Western blotting and tested for correlations between transcript levels and urinary biomarkers of tobacco use. The impact of BCRP/ABCG2 and OATP2B1/SLCO2B1 genotypes on protein expression was also examined. Oral tobacco use was associated with decreased P-gp and increased MRP1, MRP3, LAT1, and PMAT mRNA expression. Transcript levels of multiple transporters significantly correlated with tobacco biomarkers in maternal and fetal urine. In women carrying male fetuses, both smoking and oral tobacco were associated with decreased P-gp. Oral tobacco was also associated with decreased LAT1 in women carrying female fetuses. BCRP and OATP2B1 genotypes did not appear to impact protein expression. In conclusion, prenatal tobacco use is associated with altered expression of multiple placental transporters which differs by fetal sex. As transcript levels of multiple transporters were significantly correlated with tobacco use biomarkers, eliminating prenatal tobacco use should alleviate these changes.

Prenatal perfluoroalkyl substances exposure and maternal sex steroid hormones across pregnancy

BACKGROUND

Poly- and perfluoroalkyl substances (PFAS) are ubiquitous and persistent environmental contaminants that may act as endocrine disruptors in utero, but the specific endocrine pathways are unknown.

OBJECTIVE

We examined associations between maternal serum PFAS and sex steroid hormones at three time points during pregnancy.

METHODS

Pregnant women participating in the Understanding Pregnancy Signals and Infant Development (UPSIDE) study contributed biospecimens, questionnaire, and medical record data in each trimester (n = 285). PFAS (including perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA)) were analyzed in second-trimester serum samples by high-performance liquid chromatography and tandem mass spectrometry (LC-MS/MS). Total testosterone [TT], free testosterone [fT], estrone [E1], estradiol [E2], and estriol [E3]) were measured by LC-MS/MS in serum samples from each trimester. Linear mixed models with random intercepts were used to examine associations between log-transformed PFAS concentrations and hormone levels, adjusting for covariates, and stratifying by fetal sex. Results are presented as the mean percentage difference (Δ%) in hormone levels per ln-unit increase in PFAS concentration.

RESULTS

In adjusted models, PFHxS was associated with higher TT (%Δ = 20.0, 95%CI: 1.7, 41.6), particularly among women carrying male fetuses (%Δ = 15.3, 95%CI: 1.2, 30.7); this association strengthened as the pregnancy progressed. PFNA (%Δ = 7.9, 95%CI: 3.4, 12.5) and PFDA (%Δ = 7.2, 95%CI: 4.9, 9.7) were associated with higher fT, with associations again observed only in women carrying male fetuses. PFHxS was associated with higher levels of E2 and E3 in women carrying female fetuses (%Δ = 13.2, 95%CI: 0.5, 29.1; %Δ = 17.9, 95%CI: 3.2, 34.8, respectively). No associations were observed for PFOS and PFOA.

CONCLUSION

PFHxS, PFNA, and PFDA may disrupt androgenic and estrogenic pathways in pregnancy in a sex-dependent manner.

Relationships of prenatal organophosphate ester exposure with pregnancy and birth outcomes: A systematic scoping review of epidemiological studies

Exposure to organophosphate esters (OPEs) during pregnancy has been suggested to be associated with adverse pregnancy and birth outcomes. However, relevant investigations are scarce, and the findings are inconsistent. We aimed to conduct a scoping review to provide an overview of these associations. Electronic databases, including MEDLINE (through PubMed), Web of Science, and CNKI (China National Knowledge Infrastructure), were searched from inception to March 2022 and updated in July 2022. A total of 8 studies (1860 participants) were included. Limited evidence indicates that OPE exposure during pregnancy may be negatively associated with both maternal and neonatal triiodothyronine and tetraiodothyronine concentrations but positively associated with thyroid-stimulating hormone concentrations. OPE exposure during pregnancy may be associated with lower insulin concentrations. OPE exposure during pregnancy was associated with gestational age in a sex-specific manner. Intrauterine OPE exposure might increase the risk of preterm birth in female infants but decrease the risk of preterm birth in male infants. Prenatal OPE exposure might be associated with an increased risk of low birth weight. The current scoping review suggests that OPE exposure during pregnancy may disturb pregnancy and birth health, including adverse thyroid function and birth size. Because of the limited evidence obtained for most associations, additional studies followed by a traditional systematic review are needed to confirm these findings.

SSRI treatment modifies the effects of maternal inflammation on in utero physiology and offspring neurobiology

Perturbations to the in utero environment can dramatically change the trajectory of offspring neurodevelopment. Insults commonly encountered in modern human life such as infection, toxins, high-fat diet, prescription medications, and others are increasingly linked to behavioral alterations in prenatally-exposed offspring. While appreciation is expanding for the potential consequence that these triggers can have on embryo development, there is a paucity of information concerning how the crucial maternal-fetal interface (MFI) responds to these various insults and how it may relate to changes in offspring neurodevelopment. Here, we found that the MFI responds both to an inflammatory state and altered serotonergic tone in pregnant mice. Maternal immune activation (MIA) triggered an acute inflammatory response in the MFI dominated by interferon signaling that came at the expense of ordinary development-related transcriptional programs. The major MFI compartments, the decidua and the placenta, each responded in distinct manners to MIA. MFIs exposed to MIA were also found to have disrupted sex-specific gene expression and heightened serotonin levels. We found that offspring exposed to MIA had sex-biased behavioral changes and that microglia were not transcriptionally impacted. Moreover, the combination of maternal inflammation in the presence of pharmacologic inhibition of serotonin reuptake further transformed MFI physiology and offspring neurobiology, impacting immune and serotonin signaling pathways alike. In all, these findings highlight the complexities of evaluating diverse environmental impacts on placental physiology and neurodevelopment.

Associations of urinary phthalate metabolites and inflammatory biomarkers among pregnant women in Puerto Rico

Phthalates are ubiquitous environmental exposures that may be implicated in inflammatory processes, as demonstrated by previous in vivo and in vitro studies. Few human studies have substantiated these observations. This study sought to examine whether maternal phthalate exposures impact inflammatory processes, as measured by circulating inflammatory biomarkers, in the PROTECT cohort in northern Puerto Rico. Inflammatory biomarkers included matrix metalloproteinases 1, 2, and 9 (MMPs), C-reactive protein (CRP), vascular cell adhesion molecule-1 (VCAM), and intercellular cell adhesion molecule-1 (ICAM). Biomarkers were measured in maternal serum samples collected during pregnancy. 19 phthalate metabolites were assessed in urinary samples collected at three study visits across pregnancy. Phthalates with <50 % of measurements above the limit of detection were excluded from analysis. We utilized linear mixed effect models to estimate associations between interquartile range increases in phthalate metabolite concentrations and percent changes in inflammatory biomarkers. Our results revealed significant associations between mono-n-butyl phthalate (MBP) and higher MMP1 by 7.86 % (95 % CI: 0.49, 15.76) and between mono oxononyl phthalate (MONP) and higher MMP2 by 8.30 % (95 % CI: 2.22, 14.75). We observed negative or null associations between phthalate metabolites and MMP2, MMP9, ICAM, VCAM, and CRP. Many results were significantly modified by fetal sex, particularly those between di-2-ethylhexyl phthalate (DEHP) metabolites and MMP1 (p-interaction: MEHHP = 0.01, MEOHP = 0.04, MECPP = 0.01) and MMP2 (p-interaction: MEHHP = 0.03, MEOHP = 0.01, MECPP = 0.01), for which associations were positive among only women carrying female fetuses. MMPs have been previously associated with preeclampsia and hypertensive pregnancy disorders as mediators of artery remodeling. Hence, our findings suggest a potential role for phthalates in mediating the maternal inflammatory response, as well as significant sexual dimorphism in these relationships, which has implications for several adverse pregnancy outcomes.

Can paternal environmental experiences affect the breast cancer risk in offspring? A systematic review

INTRODUCTION

Studies in recent years have shown that parental environmental experiences can affect their offspring's risk of breast cancer (BC). We assessed the effect of different paternal factors on BC risk in offspring by reviewing the existing literature.

METHOD

This systematic review followed the Joanna Briggs Institute's (JBI) method for systematic reviews of qualitative evidence. The primary keywords were searched in reliable databases such as PubMed, Google Scholar, Elsevier, SID, and Wiley in English until 31 December 2021. Two authors independently examined the articles in terms of inclusion criteria and quality assessment of the articles.

RESULTS

Of the 438 studies, 19 met the inclusion criteria of this systematic review and were included in the study. Paternal factors investigated in these studies included age at delivery, diet, occupational exposures, occupation type and education. The reported relationships between these factors and breast cancer varied among different studies.

CONCLUSION

Studies considered in this article show that fathers' age at the time of delivery of the child, dietary habits, overweight and occupational factors can affect the incidence of BC risk in the next generation.

Maternal Dexamethasone Exposure Induces Sex-Specific Changes in Histomorphology and Redox Homeostasis of Rat Placenta

As the mediator between the mother and fetus, the placenta allows the most appropriate environment and optimal fetal growth. The placenta of one sex sometimes has a greater ability over the other to respond to and protect against possible maternal insults. Here, we characterized sex differences in the placenta’s morphological features and antioxidant status following dexamethasone (Dx) exposure. Pregnant rats were exposed to Dx or saline. The placenta was histologically and stereologically analyzed. The activity of the antioxidant enzymes, lipid peroxides (TBARS), superoxide anion and nitric oxide (NO) was measured. The decrease in placental zone volumes was more pronounced (p < 0.05) in female placentas. The volume density of PCNA-immunopositive nuclei was reduced (p < 0.05) in both sexes. The reduced (p < 0.05) antioxidant enzyme activities, enhanced TBARS and NO concentration indicate that Dx exposure triggered oxidative stress in the placenta of both fetal sexes, albeit stronger in the placenta of female fetuses. In conclusion, maternal Dx treatment reduced the size and volume of placental zones, altered placental histomorphology, decreased cell proliferation and triggered oxidative stress; however, the placentas of female fetuses exerted more significant responses to the treatment effects. The reduced placental size most probably reduced the transport of nutrients and oxygen, thus resulting in the reduced weight of fetuses, similar in both sexes. The lesser ability of the male placenta to detect and react to maternal exposure to environmental challenges may lead to long-standing health effects.

Advanced Maternal Age Differentially Affects Embryonic Tissues with the Most Severe Impact on the Developing Brain

Advanced maternal age (AMA) poses the single greatest risk to a successful pregnancy. Apart from the impact of AMA on oocyte fitness, aged female mice often display defects in normal placentation. Placental defects in turn are tightly correlated with brain and cardiovascular abnormalities. It therefore follows that placenta, brain and heart development may be particularly susceptible to the impact of AMA. In the current study, we compared global transcriptomes of placentas, brains, hearts, and facial prominences from mid-gestation mouse conceptuses developed in young control (7-13 wks) and aging (43-50 wks) females. We find that AMA increases transcriptional heterogeneity in all tissues, but particularly in fetal brain. Importantly, even overtly normally developed embryos from older females display dramatic expression changes in neurodevelopmental genes. These transcriptomic alterations in the brain are likely induced by defects in placental development. Using trophoblast stem cells (TSCs) as a model, we show that exposure to aging uterine stromal cell-conditioned medium interferes with normal TSC proliferation and causes precocious differentiation, recapitulating many of the defects observed in placentas from aged females. These data highlight the increased risk of AMA on reproductive outcome, with neurodevelopment being the most sensitive to such early perturbations and with potential for lifelong impact.

Protein Supplementation during Mid-Gestation Alters the Amino Acid Patterns, Hepatic Metabolism, and Maternal Skeletal Muscle Turnover of Pregnant Zebu Beef Cows

From 100 to 200 days of gestation, 52 cows carrying male (n = 30) or female (n = 22) fetuses were assigned to CON (basal diet-5.5% of CP, n = 26) or SUP (basal diet + protein supplement [40% CP, 3.5 g/kg BW]-12% of CP, n = 26) treatments. Glucose concentrations decreased at 200 (p ≤ 0.01; CON = 46.9 and SUP = 54.7 mg/dL) and 270 days (p ≤ 0.05; CON = 48.4 and SUP = 53.3 mg/dL) for CON compared to SUP. The same pattern occurred for insulin (p ≤ 0.01). At parturition, the NEFA concentration was greater (p = 0.01, 0.10 vs. 0.08 mmol/L) for CON than for SUP. Total AA increased in SUP (p ≤ 0.03) at mid- and late-gestation compared to CON. At 200 days, CON dams carrying females had less essential AA (p = 0.01) than cows carrying males. The SUP dams had greater expressions of protein synthesis markers, namely eIf4E and GSK3β (p ≤ 0.04), at day 200 and of MuFR1 (protein degradation marker, p ≤ 0.04) at parturition. Supplemented cows had higher hepatic pyruvate carboxylase expressions (p = 0.02). Therefore, PS alleviates the restriction overload on maternal metabolism.

Associations between prenatal multiple plasma metal exposure and newborn telomere length: Effect modification by maternal age and infant sex

Exposure to metals during pregnancy may affect maternal and infant health. However, studies on the combined effects of metals on the telomere length (TL) of newborns are limited. A prospective cohort study was conducted among 1313 mother-newborn pairs in the Guangxi Zhuang Birth Cohort. The concentrations of metals in maternal plasma during the first trimester were measured using inductively coupled plasma-mass spectrometry. We explored the associations between nine plasma metals and newborn TL using generalized linear models (GLMs), principal component analysis (PCA), quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). The GLMs revealed the inverse association between plasma arsenic (percent change, -5.56%; 95% CI: -7.69%, -3.38%) and barium concentrations (-9.84%; 95% CI: -13.81%, -5.68%) and newborn TL. Lead levels were related to significant decreases in newborn TL only in females. The PCA revealed a negative association between the PC3 and newborn TL (-4.52%; 95% CI: -6.34%, -2.68%). In the BKMR, the joint effect of metals was negatively associated with newborn TL. Qgcomp indicated that each one-tertile increase in metal mixture levels was associated with shorter newborn TL (-9.39%; 95% CI: -14.32%, -4.18%). The single and joint effects of multiple metals were more pronounced among pregnant women carrying female fetuses and among pregnant women <28 years of age. The finding suggests that prenatal exposure to arsenic, barium, antimony, and lead and mixed metals may shorten newborn TLs. The relationship between metal exposures and newborn TL may exhibit heterogeneities according to infant sex and maternal age.

Windows of Vulnerability: Consequences of Exposure Timing during the Dutch Hunger Winter

Prior research on early-life exposures to famine has established in utero development as a critical period of vulnerability to malnutrition. Yet, previous research tends to focus narrowly on this stage, at the expense of a more comprehensive examination of childhood. As a result, the literature has yet to compare the severity of the consequences of exposure to malnutrition across developmentally salient periods. Such comparison is crucial not only in the magnitude of effects but also in the nature of outcomes. Using a restricted population registry-linked health survey, this study examines the Dutch Hunger Winter to provide a comprehensive examination of the long-term consequences of in utero, infant, childhood, and adolescent exposure to famine. The results show malnutrition leads to heterogeneous effects depending on when the exposure occurs. In utero exposure to malnutrition leads to deleterious conditions in physical health and lower socioeconomic attainment. For older cohorts, results suggest a resilience to the effects of malnutrition on physical health in late life, but a higher vulnerability to socioeconomic stunting. Furthermore, the results suggest important gender differences in the long-term impact of malnutrition. Males consistently show stronger negative consequences across a wider array of conditions.

Maternal exposure to metal mixtures during early pregnancy and fetal growth in the Jiangsu Birth Cohort, China

Previous epidemiological studies have reported that prenatal exposure to metals might have influence on fetal growth. Most studies assessed the effect of individual metals, while the investigation on the relationship between multiple metal exposure and fetal growth is sparse. The objective of the present study is to assess the joint impact of metal mixtures on fetal growth during pregnancy. A total of 1275 maternal-infant pairs from the Jiangsu Birth Cohort (JBC) Study were included to investigate the effect of maternal metal exposure on fetal biometry measures at 22-24, 30-32, and 34-36 weeks of gestation. Lead (Pb), arsenic (As), cadmium (Cd), mercury (Hg), chromium (Cr), vanadium(V), thallium (Tl) and barium (Ba) were measured by inductively coupled plasma mass spectrometry (ICP-MS) in maternal urine samples collected in the first trimester. We used general linear models and restricted cubic splines to test dose-response relationships between single metals and fetal growth. The weighted quantile sum (WQS) models were then applied to evaluate the overall effect of all these metals. We observed inverse associations of exposure to Pb, V and Cr with estimated fetal weight (EFW) at 34-36 weeks of gestation. Notably, maternal exposure to metal mixtures was significantly associated with reduced EFW at 34-36 weeks of gestation after adjusting for some covariates and confounders (aβ -0.05 [95% CI: 0.09, -0.01], P = 0.023), and this association was mainly driven by Cr (30.41%), Pb (23.92%), and Tl (15.60%). These findings indicated that prenatal exposure to metal mixtures might impose adverse effects on fetal growth.

Placental macrophage responses to viral and bacterial ligands and the influence of fetal sex

Bacterial and viral infections of the placenta are associated with inflammation and adverse pregnancy outcomes. Hofbauer cells (HBCs) are fetal-origin macrophages in the placenta, proposed to protect the fetus from vertical pathogen transmission. We performed quantitative proteomics on term HBCs under resting conditions and following exposure to bacterial and viral pathogen-associated molecular patterns (PAMPs), and investigated the contribution of fetal sex. Resting HBCs expressed proteins pertinent to macrophage function, including chemokines, cytokines, Toll-like receptors, and major histocompatibility complex class I and II molecules. HBCs mounted divergent responses to bacterial versus viral PAMPs but exhibited protein expression changes suggestive of a more pro-inflammatory phenotype. A comparison between male and female HBCs showed that the latter mounted a stronger and wider response. Here, we provide a comprehensive understanding of the sex-dependent responses of placental macrophages to infectious triggers, which were primarily associated with lipid metabolism in males and cytoskeleton organization in females.

Maternal Plasma Glycerophospholipids LC-PUFA Levels Have a Sex-Specific Association with the Offspring's Cord Plasma Glycerophospholipids-Fatty Acid Desaturation Indices at Birth

Fatty acid desaturases, the enzymes responsible for the production of unsaturated fatty acids (FA) in fetal tissues, are known to be influenced by maternal-placental supply of nutrients and hormones for their function. We hypothesize that there could be a gender-specific regulation of unsaturated FA metabolism at birth, dependent on the maternal fatty acid levels. In this study, 153 mother-newborn pairs of uncomplicated and 'full-term' pregnancies were selected and the FA composition of plasma glycerophospholipids (GP) was quantified by gas chromatography. The FA composition of mother blood plasma (MB) was compared with the respective cord blood plasma (CB) of male newborns or female newborns. Product to substrate ratios were estimated to calculate delta 5 desaturase (D5D), delta 6 desaturase (D6D) and delta 9 stearoyl-CoA-desaturase (D9D/SCD) indices. Pearson correlations and linear regression analyses were employed to determine the associations between MB and CB pairs. In the results, the male infant's MB-CB association was positively correlated with the SCD index of carbon-16 FA, while no correlation was seen for the SCD index of carbon-18 FA. Unlike for males, the CB-D5D index of female neonates presented a strong positive association with the maternal n-6 long chain-polyunsaturated FA (LC-PUFA), arachidonic acid. In addition, the lipogenic desaturation index of SCD18 in the CB of female new-borns was negatively correlated with their MB n-3 DHA. In conclusion, sex-related differences in new-borns' CB desaturation indices are associated with maternal LC-PUFA status at the time of the birth. This examined relationship appears to predict the origin of sex-specific unsaturated FA metabolism seen in later life.

Maternal diet quality moderates associations between parabens and birth outcomes

BACKGROUND/OBJECTIVE

Maternal paraben exposure and diet quality are both independently associated with birth outcomes, but whether these interact is unknown. We assessed sex-specific associations of parabens with birth outcomes and differences by maternal diet quality.

METHODS

Illinois pregnant women (n = 458) provided five first-morning urines collected at 8-40 weeks gestation, which we pooled for quantification of ethylparaben, methylparaben, and propylparaben concentrations. We collected/measured gestational age at delivery, birth weight, body length, and head circumference within 24 h of birth, and calculated sex-specific birth weight-for-gestational-age z-scores and weight/length ratio. Women completed three-month food frequency questionnaires in early and mid-to-late pregnancy, which we used to calculate the Alternative Healthy Eating Index (AHEI)-2010. Linear regression models evaluated sex-specific associations of parabens with birth outcomes, and differences in associations by average pregnancy AHEI-2010.

RESULTS

In this predominately non-Hispanic white, college-educated sample, maternal urinary paraben concentrations were only modestly inversely associated with head circumference and gestational length. However, methylparaben and propylparaben were inversely associated with birth weight, birth weight z-scores, body length, and weight/length ratio in female, but not male newborns. For example, each 2-fold increase in methylparaben concentrations was associated with -46.61 g (95% CI: -74.70, -18.51) lower birth weight, -0.09 (95% CI: -0.15, -0.03) lower birth weight z-scores, -0.21 cm (95% CI: -0.34, -0.07) shorter body length, and -0.64 g/cm (95% CI: -1.10, -0.19) smaller weight/length ratio in females. These inverse associations were more prominent in females of mothers with poorer diets (AHEI-2010 < median), but attenuated in those with healthier diets (AHEI-2010 ≥ median). In newborn males of mothers with healthier diets, moderate inverse associations emerged for propylparaben with gestational length and head circumference.

CONCLUSIONS

Maternal diet may moderate associations of parabens with birth size in a sex-specific manner. Additional studies may consider understanding the inflammatory and metabolic mechanisms underlying these findings.

Sources and Translational Relevance of Heterogeneity in Maternal Immune Activation Models

The epidemiological literature reporting increased risk for neurodevelopmental and psychiatric disorders after prenatal exposure to maternal immune activation (MIA) is still evolving, and so are the attempts to model this association in animals. Epidemiological studies of MIA offer the advantage of directly evaluating human populations but are often limited in their ability to uncover pathogenic mechanisms. Animal models, on the other hand, are limited in their generalizability to psychiatric disorders but have made significant strides toward discovering causal relationships and biological pathways between MIA and neurobiological phenotypes. Like in any other model system, both planned and unplanned sources of variability exist in animal models of MIA. Therefore, the design, implementation, and interpretation of MIA models warrant a careful consideration of these sources, so that appropriate strategies can be developed to handle them satisfactorily. While every research group may have its own strategy to this aim, it is essential to report the methodological details of the chosen MIA model in order to enhance the transparency and comparability of models across research laboratories. Even though it poses a challenge for attempts to compare experimental findings across laboratories, variability does not undermine the utility of MIA models for translational research. In fact, variability and heterogenous outcomes in MIA models offer unique opportunities for new discoveries and developments in this field, including the identification of disease pathways and molecular mechanisms determining susceptibility and resilience to MIA. This review summarizes the most important sources of variability in animal models of MIA and discusses how model variability can be used to investigate neurobiological and immunological factors causing phenotypic heterogeneity in offspring exposed to MIA.

Maternal and Fetal PI3K-p110α Deficiency Induces Sex-Specific Changes in Conceptus Growth and Placental Mitochondrial Bioenergetic Reserve in Mice

Fetal growth is reliant on placental formation and function, which, in turn, requires the energy produced by the mitochondria. Prior work has shown that both mother and fetus operate via the phosphoinositol 3-kinase (PI3K)-p110α signalling pathway to modify placental development, function, and fetal growth outcomes. This study in mice used genetic inactivation of PI3K-p110α (α/+) in mothers and fetuses and high resolution respirometry to investigate the influence of maternal and fetal PI3K-p110α deficiency on fetal and placental growth, in relation to placental mitochondrial bioenergetics, for each fetal sex. The effect of PI3K-p110α deficiency on maternal body composition was also determined to understand more about the maternal-driven changes in feto-placental development. These data show that male fetuses were more sensitive than females to fetal PI3K-p110α deficiency, as they had greater reductions in fetal and placental weight, when compared to their WT littermates. Placental weight was also altered in males only of α/+ dams. In addition, α/+ male, but not female, fetuses showed an increase in mitochondrial reserve capacity, when compared to their WT littermates in α/+ dams. Finally, α/+ dams exhibited reduced adipose depot masses, compared to wild-type dams. These findings, thus, demonstrate that maternal nutrient reserves and ability to apportion nutrients to the fetus are reduced in α/+ dams. Moreover, maternal and fetal PI3K-p110α deficiency impacts conceptus growth and placental mitochondrial bioenergetic function, in a manner dependent on fetal sex.

Association of prenatal exposure to ambient air pollution with adverse birth outcomes and effect modification by socioeconomic factors

BACKGROUND

Maternal exposure to air pollution has been associated with birth outcomes; however, few studies examined biologically critical exposure windows shorter than trimesters or potential effect modifiers.

OBJECTIVES

To examine associations of prenatal fine particulate matter (PM_2.5), by trimester and in biologically critical windows, with birth outcomes and assess potential effect modifiers.

METHODS

This study used two pregnancy cohorts (CANDLE and TIDES; N = 2099) in the ECHO PATHWAYS Consortium. PM_2.5 was estimated at the maternal residence using a fine-scale spatiotemporal model, averaged over pregnancy, trimesters, and critical windows (0-2 weeks, 10-12 weeks, and last month of pregnancy). Outcomes were preterm birth (PTB, <37 completed weeks of gestation), small-for-gestational-age (SGA), and continuous birthweight. We fit multivariable adjusted linear regression models for birthweight and Poisson regression models (relative risk, RR) for PTB and SGA. Effect modification by socioeconomic factors (maternal education, household income, neighborhood deprivation) and infant sex were examined using interaction terms.

RESULTS

Overall, 9% of births were PTB, 10.4% were SGA, and mean term birthweight was 3268 g (SD = 558.6). There was no association of PM_2.5 concentration with PTB or SGA. Lower birthweight was associated with higher PM_2.5 averaged over pregnancy (β -114.2, 95%CI -183.2, -45.3), during second (β -52.9, 95%CI -94.7, -11.2) and third (β -45.5, 95%CI -85.9, -5.0) trimesters, and the month prior to delivery (β -30.5, 95%CI -57.6, -3.3). Associations of PM_2.5 with likelihood of SGA and lower birthweight were stronger among male infants (p-interaction ≤0.05) and in those with lower household income (p-interaction = 0.09).

CONCLUSIONS

Findings from this multi city U.S. birth cohort study support previous reports of inverse associations of birthweight with higher PM_2.5 exposure during pregnancy. Findings also suggest possible modification of this association by infant sex and household income.

Fetal sex and risk of preeclampsia: Dose maternal race matter?

OBJECTIVE

To examine whether maternal race could affect the relationship between fetal sex and preeclampsia.

MATERIAL AND METHODS

This study was a cohort analysis using prospectively collected data from pregnant women who participated in the Vitamin Antenatal Asthma Reduction Trial (VDAART). Preeclampsia was the secondary outcome of VDAART. We examined the association of fetal sex with preeclampsia and its potential interaction with maternal race in 813 pregnant women (8% with preeclampsia) in logistic regression models with adjustment for preterm birth (<37 weeks of gestation), maternal age, education, and body mass index at enrollment and clinical center. We further conducted a race stratified analysis and also examined whether any observed association was dependent on the gestational age at delivery and prematurity.

RESULTS

In an analysis of all races combined, preeclampsia was not more common among pregnant women with a male fetus compared to those with a female fetus (odds ratio [OR] = 1.3, 95% CI = 0.81, 2.24). There was an interaction between African American race and fetal sex in association with preeclampsia after adjustment for preterm delivery and other potential confounders (p = .014). In race stratified analyses, we observed higher odds of preeclampsia among African American pregnant women who carried male fetuses after adjustment for preterm delivery and other potential confounders (adjusted OR = 2.4, 95% CI = 1.12, 5.60).

CONCLUSION

We observed fetal sexual dimorphic differences in the occurrence of preeclampsia in African American women, but not in Whites. Information on fetal sex may ultimately improve the prediction of pre-eclampsia in African American mothers, who might be at higher risk for this adverse condition in pregnancy.

Sex-dependent differential transcript expression in the placenta of growth restricted infants

INTRODUCTION

The pathological decrease of fetal growth during gestation can lead to subsequent poor health outcomes for the fetus. This process is commonly controlled by the placenta, the interface between mother and baby during gestation. Sex-specific gene expression has been implicated in placental function, therefore, there is a need to determine if it is important during reduced fetal growth. We therefore aimed to characterise placental gene expression at term to evaluate sex-specific genetic changes that occur in small for gestational age (SGA) infants.

METHODS

RNA-sequencing of twelve human placental tissue samples collected from pregnancies yielding either term appropriate for gestational age (AGA) or SGA infants identified at delivery. Candidate genes associated with fetal size and fetal sex were identified using differential gene expression and weighted gene co-expression network analyses. Single-cell sequencing data was used for candidate validation and to estimate candidate transcript expression in specific placental cell populations.

RESULTS

Differential gene expression and weighted gene co-expression network analyses identified 403 candidate transcripts associated with SGA infants. One hundred and three of these transcripts showed sex-specific expression. . Published placental sequencing datasets were used to validate the key expression results from the twelve placental samples initially studied; the sex-independent transcript expression for genes involved in cell cycle processes in males (7 transcripts) and endoplasmic reticulum stress in females (17 transcripts).

DISCUSSION

This study identified the activation of multiple molecular mechanisms involved in the placental response to an adverse environmental stressor. Mechanisms such as disrupted protein synthesis were shared between infant biological sex when comparing AGA to SGA, whilst other pathways such as cell cycle and endoplasmic reticulum stress appear as independent/specific to either males or females when investigating reduced fetal growth. This data suggests that sexual dimorphism is an important consideration when examining placental dysfunction and poor fetal growth.

Influence of Gender in Diabetes Mellitus and Its Complication

In medicine, there is growing evidence that gender differences are important and lead to variations in the pathophysiology and treatment of many diseases with traits that appear to be particularly relevant in influencing the outcomes of many morbid forms. Today, the inclusion of gender in biomedical research, to improve the scientific quality and scientific relevance of knowledge, of technology is an increasingly present element precisely due to the practical implications that derive from it. Gender differences describe the biological variability between women and men, which is, in turn, related to differences in the information contained in sex chromosomes, the specific gene expression of autosomes linked to sex, the different number and quality of sex hormones, and their different effects on systems and organs, without neglecting the fact that each of the sexes has different target organs on which these hormones act. Additionally, both genders undergo metabolic changes throughout their lives, and this is especially true for women who show more dramatic changes due to their role in reproduction. Gender differences are not only the result of our genetic makeup but are also mixed with socio-cultural habits, behaviors, and lifestyles, differences between women and men, exposure to specific environmental influences, different food and lifestyle styles or stress, or different attitude in compliance with treatments and disease prevention campaigns. Gender differences also affect behavior throughout life, and physical changes can have implications for lifestyle, social roles, and mental health. Therefore, determinism and therapeutic outcome in chronic diseases are influenced by a complex combination of biological and environmental factors, not forgetting that there are many interactions of social and biological factors in women and men. This review will address the role of gender differences in the management of various forms of diabetes and its complications considering the different biological functions of hormones, the difference in body composition, physiological differences in glucose and fat metabolism, also considering the role of the microbiota. intestinal, as well as the description of gestational diabetes linked to possible pathophysiological events typical of reproduction.

The effect and its critical window for ambient temperature and humidity in pregnancy on term low birth weight

As common meteorological factors in daily life, there is limited evidence for the effect of ambient temperature and humidity during pregnancy on the risk of term low birth weight. Furthermore, little is known about the interaction of ambient temperature and humidity on TLBW. The objective of the study was to explore the effect of ambient temperature, humidity during pregnancy, and their interaction on the risk of TLBW and, moreover, to identify exposure critical window. We recruited 6640 infants and their mothers to build a birth cohort study in Jinan City, China, from January 2018 to December 2019. The associations between temperature and humidity during pregnancy and TLBW were estimated by generalized additive model, logistic regression model, and interaction analysis, and the critical window was identified by the distributed lag non-linear model. The incidence of TLBW was 1.36% for the infants in the birth cohort. TLBW was related to the low level of temperature and humidity in the whole pregnancy, compared with the moderate level and the adjusted ORs were 4.44 (1.65-11.42) and 6.23 (1.92-21.39), respectively. The indicators of the interaction analysis of temperature and humidity were not statistically significant. For the low level of humidity, the association with TLBW was statistically significant at first to sixth gestational weeks, and the maximum OR in male infants (3.95, 1.70-9.16) was higher than that in females (1.96, 1.06-3.63). For the low level of temperature, we failed to find significant association with TLBW at each gestational week. The low level of temperature and humidity during pregnancy could increase the risk of TLBW. There was no statistical interaction between temperature and humidity on TLBW. Moreover, the early stage of pregnancy was the critical window for humidity exposure, in which the boys had a greater effect.

Neurosteroids and early-life programming: An updated perspective

Early-life stress can lead to detrimental offspring outcomes, including an increased risk for mood disorders and hypothalamic-pituitary-adrenal axis dysregulation. Neurosteroids bind to ligand-gated neurotransmitter receptors, rapidly modulating neuronal excitability and promoting termination of stress responses. Reduced neurosteroidogenesis underlies some of the aberrant neuroendocrine and behavioural phenotypes observed in adult prenatally stressed rodents. During development, disruptions in neurosteroid generation and action also lead to long-term programming effects on the off-spring's brain and behaviour. Here, we review recent advances in the field, focusing on the interaction between neurosteroids and early-life stress outcomes in adulthood and in the perinatal period. We also discuss the direction of future research, with emphasis on quantification methods, sex differences, and neurosteroids as targets for therapeutic intervention.

EGCG exposure during pregnancy affects uterine histomorphology in F1 female mice and the underlying mechanisms

Although epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been shown to have many benefits, the effect of EGCG exposure in utero on adult uterine development is unclear. In this study, pregnant C57BL/6 mice were exposed to 1 mg/kg body weight (bw) EGCG dissolved in drinking water from gestational days 0.5-16.5. A significant decrease in uterine weight was observed in the adult female mice, accompanied by uterine atrophy, inflammation, and fibrosis in the endometrium. Uterine atrophy was attributed to the thinning of the endometrial stromal layer and a significant reduction in endometrial cell proliferation. The expression levels of related proteins in the NF-κB and RAF/MEK/ERK signaling pathways were significantly increased, which might be responsible for the occurrence of inflammation. Activation of the transforming growth factor beta (TGF-β1)/Smad signaling pathway might be involved in the development of endometrial fibrosis. The changes in the expression of estrogen receptor α, β (ERα, ERβ), progesterone receptor (PGR), and androgen receptor (AR) might lead to changes in the aforementioned signaling pathways. The promoter region methylation level of Esr2 was increased, and the expression of DNMT3A was evaluated. Our study indicates a risk of EGCG intake during pregnancy affecting uterine development in offspring.

Sex-dependence and comorbidities of the early-life adversity induced mental and metabolic disease risks: Where are we at?

Early-life adversity (ELA) is a major risk factor for developing later-life mental and metabolic disorders. However, if and to what extent ELA contributes to the comorbidity and sex-dependent prevalence/presentation of these disorders remains unclear. We here comprehensively review and integrate human and rodent ELA (pre- and postnatal) studies examining mental or metabolic health in both sexes and discuss the role of the placenta and maternal milk, key in transferring maternal effects to the offspring. We conclude that ELA impacts mental and metabolic health with sex-specific presentations that depend on timing of exposure, and that human and rodent studies largely converge in their findings. ELA is more often reported to impact cognitive and externalizing domains in males, internalizing behaviors in both sexes and concerning the metabolic dimension, adiposity in females and insulin sensitivity in males. Thus, ELA seems to be involved in the origin of the comorbidity and sex-specific prevalence/presentation of some of the most common disorders in our society. Therefore, ELA-induced disease states deserve specific preventive and intervention strategies.

Prenatal exposure to particulate matter and placental gene expression

BACKGROUND

While strong evidence supports adverse maternal and offspring consequences of air pollution, mechanisms that involve the placenta, a key part of the intrauterine environment, are largely unknown. Previous studies of air pollution and placental gene expression were small candidate gene studies that rarely considered prenatal windows of exposure or the potential role of offspring sex. We examined overall and sex-specific associations of prenatal exposure to fine particulate matter (PM_2.5) with genome-wide placental gene expression.

METHODS

Participants with placenta samples, collected at birth, and childhood health outcomes from CANDLE (Memphis, TN) (n = 776) and GAPPS (Seattle, WA) (n = 205) cohorts of the ECHO-PATHWAYS Consortium were included in this study. PM_2.5 exposures during trimesters 1, 2, 3, and the first and last months of pregnancy, were estimated using a spatiotemporal model. Cohort-specific linear adjusted models were fit for each exposure window and expression of >11,000 protein coding genes from paired end RNA sequencing data. Models with interaction terms were used to examine PM_2.5-offspring sex interactions. False discovery rate (FDR < 0.10) was used to correct for multiple testing.

RESULTS

Mean PM_2.5 estimate was 10.5-10.7 μg/m³ for CANDLE and 6.0-6.3 μg/m³ for GAPPS participants. In CANDLE, expression of 13 (11 upregulated and 2 downregulated), 20 (11 upregulated and 9 downregulated) and 3 (2 upregulated and 1 downregulated) genes was associated with PM_2.5 in the first trimester, second trimester, and first month, respectively. While we did not find any statistically significant association, overall, between PM_2.5 and gene expression in GAPPS, we found offspring sex and first month PM_2.5 interaction for DDHD1 expression (positive association among males and inverse association among females). We did not observe PM_2.5 and offspring sex interactions in CANDLE.

CONCLUSION

In CANDLE, but not GAPPS, we found that prenatal PM_2.5 exposure during the first half of pregnancy is associated with placental gene expression.

Effects of prenatal opioid and alcohol exposures on immune and serotonin factors in human placenta

PURPOSE

Opioids and alcohol impact critical serotonin (5-HT) function in the developing placenta and fetus through the actions of immune proinflammatory factors. Yet, possible convergent effects of opioids and alcohol on human placental toll-like receptor 4 (TLR4) activation and subsequent 5-HT homeostasis remain entirely unknown. The purpose of this study was to examine the effect of prenatal exposure to opioids with or without prenatal alcohol exposure (PAE) on the expression of key placental immune and serotonin signaling factors in human placental tissue obtained from a well-characterized prospective cohort.

METHODS

Data were collected from a subset of participants enrolled in the prospective pre-birth Ethanol, Neurodevelopment, Infant, and Child Health (ENRICH-1) cohort. Women were recruited and classified into four study groups: 1) PAE (n = 20); 2) those taking medications for opioid use disorder (MOUD; n = 28), 3) concurrent PAE and MOUD (n = 20); and 4) controls (HC; n = 20) based on prospective, repeated self-report, and biomarker analysis. Placenta samples underwent tissue processing to identify mRNA for TLR4, nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), serotonin transporter (SERT), tryptophan hydroxylase (TPH1), indoleamine 2,3-Dioxygenase 1 (IDO) as well as protein concentrations of TLR4, IL-1β, TNF-α, SERT. To consider the association between study group and mRNA/protein expression of our targets, multivariable regression models were developed with inclusion of a priori selected covariates.

RESULTS

There was a significant negative association between PAE and SERT mRNA (β = -0.01; p < 0.01) and a positive association with TPH1 mRNA expression (β = 0.78; p < 0.05). In addition, there was a negative association between MOUD and TNF-α protein expression (β = -0.12; p < 0.05).

CONCLUSIONS

This study provides the first evidence that PAE may inhibit SERT expression while simultaneously promoting increased TPH1 protein expression in human placenta. This may result in increased 5-HT in fetal circulation known to affect neurodevelopment. Our data suggest that opioids and alcohol may disturb the bidirectional, dynamic interaction between the placental immune and serotonin system. Given the implication for brain development and health across the life-span further investigation of these critical mechanisms in well-defined cohorts is required.

Modelling human placental villous development: designing cultures that reflect anatomy

The use of in vitro tools to study trophoblast differentiation and function is essential to improve understanding of normal and abnormal placental development. The relative accessibility of human placentae enables the use of primary trophoblasts and placental explants in a range of in vitro systems. Recent advances in stem cell models, three-dimensional organoid cultures, and organ-on-a-chip systems have further shed light on the complex microenvironment and cell-cell crosstalk involved in placental development. However, understanding each model's strengths and limitations, and which in vivo aspects of human placentation in vitro data acquired does, or does not, accurately reflect, is key to interpret findings appropriately. To help researchers use and design anatomically accurate culture models, this review both outlines our current understanding of placental development, and critically considers the range of established and emerging culture models used to study this, with a focus on those derived from primary tissue.

Placental structure, function, and mitochondrial phenotype relate to fetal size in each fetal sex in mice†

Fetal growth depends on placental function, which requires energy from mitochondria. Here we investigated whether mitochondrial function in the placenta relates to the growth of the lightest and heaviest fetuses of each sex within the litter of mice. Placentas from the lightest and heaviest fetuses were taken to evaluate placenta morphology (stereology), mitochondrial energetics (high-resolution respirometry), mitochondrial regulators, nutrient transporters, hormone handling, and signaling pathways (qPCR and Western blotting). We found that mitochondrial complex I and II oxygen consumption rate was greater for placentas supporting the lightest female fetuses, although placental complex I abundance of the lightest females and complexes III and V of the lightest males were decreased compared to their heaviest counterparts. Expression of mitochondrial biogenesis (Nrf1) and fission (Drp1 and Fis1) genes was lower in the placenta from the lightest females, whilst biogenesis-related gene Tfam was greater in the placenta of the lightest male fetuses. In addition, placental morphology and steroidogenic gene (Cyp17a1 and Cyp11a1) expression were aberrant for the lightest females, but glucose transporter (Slc2a1) expression was lower in only the lightest males versus their heaviest counterparts. Differences in intra-litter placental phenotype were related to changes in the expression of hormone-responsive (androgen receptor) and metabolic signaling (AMPK, AKT, and PPARγ) pathways. Thus, in normal mouse pregnancy, placental structure, function, and mitochondrial phenotype are differentially responsive to the growth of the female and male fetus. This study may inform the design of sex-specific therapies for placental insufficiency and fetal growth abnormalities with life-long benefits for the offspring.

Alcohol induced increases in sperm Histone H3 lysine 4 trimethylation correlate with increased placental CTCF occupancy and altered developmental programming

Using a mouse model, studies by our group reveal that paternal preconception alcohol intake affects offspring fetal-placental growth, with long-lasting consequences on adult metabolism. Here, we tested the hypothesis that chronic preconception male alcohol exposure impacts histone enrichment in sperm and that these changes are associated with altered developmental programming in the placenta. Using chromatin immunoprecipitation, we find alcohol-induced increases in sperm histone H3 lysine 4 trimethylation (H3K4me3) that map to promoters and presumptive enhancer regions enriched in genes driving neurogenesis and craniofacial development. Given the colocalization of H3K4me3 with the chromatin binding factor CTCF across both sperm and embryos, we next examined CTCF localization in the placenta. We find global changes in CTCF binding within placentae derived from the male offspring of alcohol-exposed sires. Furthermore, altered CTCF localization correlates with dysregulated gene expression across multiple gene clusters; however, these transcriptional changes only occur in male offspring. Finally, we identified a correlation between genomic regions exhibiting alcohol-induced increases in sperm H3K4me3 and increased CTCF binding in male placentae. Collectively, our analysis demonstrates that the chromatin landscape of sperm is sensitive to chronic alcohol exposure and that a subset of these affected regions exhibits increased placental CTCF enrichment.

Sexually Dimorphic Accumulation of Persistent Organic Pollutants in Fetuses

Living in an industrialized era, we are exposed to man-made chemicals including persistent organic pollutants (POPs). Previous studies have shown associations of POP exposure with adverse outcomes in humans, wildlife, and the environment, making it a global concern. Exposure during sensitive windows of susceptibility such as fetal development is of particular concern because of the potential increased risk of developing diseases in childhood and adulthood. However, there are limited studies on the sexual dimorphism of POP accumulation during the prenatal period. In this mini-review, we focus on differences in POP concentrations in the placenta and fetal tissues between males and females. We also show the sexually dimorphic adverse outcomes of prenatal exposure to POPs. Overall, our summary shows that males may accumulate higher concentrations of POPs in the placenta and fetal tissues compared to females, although studies are sparse and inconsistent. In addition, there are differences in adverse health outcomes associated to prenatal POP exposure according to sex. Hence, we highly urge researchers investigating the health effects of POP exposure to consider sexual dimorphism in their studies.

Joint associations among prenatal metal mixtures and nutritional factors on birth weight z-score: Evidence from an urban U.S. population

The benefits of nutritional factors on birth outcomes have been recognized, however, limited studies have examined the role of nutritional factors in mitigating the detrimental effects of metals exposure during gestation. We used data collected from 526 mother-infant dyads enrolled in the Programming of Intergenerational Stress Mechanisms longitudinal pregnancy cohort to examine the joint effects of prenatal exposure to metals and maternal nutrition on birth weight for gestational age (BWGA) z-scores. We measured concentrations of twelve metals and trace elements in urine samples collected during pregnancy. Maternal nutritional intake was measured using the Block98 Food Frequency Questionnaire and converted into energy-adjusted consumption of individual nutrients. Using multivariable linear regression and Bayesian Kernel Machine Regression, we found that three metals [cobalt (Co), nickel (Ni), and lead (Pb)] and five metals [barium (Ba), caesium (Cs), copper (Cu), Ni, and zinc (Zn)] were associated with BWGA z-score in male and female infants, respectively. When examining the sex-specific interactions between these metals and nutrient groups [macro nutrients, minerals, A vitamins, B vitamins, anti-oxidant, methyl-donor nutrients, and inflammatory (pro- and anti-)] using a Cross-validated Kernel Ensemble model, we identified significant interactions between the macro nutrients and Co (p = 0.05), minerals and Pb (p = 0.04), and A vitamins and Ni (p = 0.001) in males. No significant interactions were found in females. Furthermore, three minerals (phosphorus, iron, potassium) and vitamin A were found to be more crucial than other nutrients in modifying the association between each respective metal and BWGA z-score in males. A better understanding of the sex-specific interactions between nutrients and metals on birth weight can guide pregnant women to protect their neonates from the adverse health impacts of metal exposures by optimizing nutrient intakes accordingly.

Are there sex differences in fetal growth strategies and in the long-term effects of pregnancy complications on cognitive functioning?

Males and females have been proposed to have different prenatal growth strategies, whereby males invest more in fetal growth and less in placental development, leaving them more susceptible to early-life adversity. We tested predictions of this hypothesis using data from the National Collaborative Perinatal Project. Male newborns were heavier than females, but there was no difference in placental weight, adjusting for birthweight. Among infants born prior to 33 weeks, the difference in birthweight between males and females was greater among those who did not survive than among those who did, potentially reflecting a strategy whereby males maintained growth in the face of prenatal insults, while females adjusted growth. However, there was no significant difference in mortality between the sexes. Being born small-for-gestational age or very preterm (prior to 33 weeks) was associated with significantly reduced performance for most of the cognitive traits examined at 7 years, although maternal preeclampsia was associated with reduced performance in fewer traits. Generally, these effects of early-life adversity (poor fetal growth, prematurity, and preeclampsia) did not differ between the sexes. However, analyzing the sexes separately (rather than testing the interaction between sex and adversity) resulted in numerous spurious sex-specific effects, whereby the effect of early-life adversity appeared to be significant in one sex but not the other. Overall, we found little support for the hypothesis that males prioritize growth more than females, and that this makes them more susceptible to early-life adversity. Furthermore, our results show that analyzing the sexes separately, rather than testing the adversity by sex interaction, can be highly misleading.

Prenatal PM2.5 exposure and infant temperament at age 6 months: Sensitive windows and sex-specific associations

BACKGROUND

Prenatal exposure to fine particulate matter with a diameter of ≤2.5 μm (PM2.5) has been linked to adverse neurodevelopmental outcomes in later childhood, while research on early infant behavior remains sparse.

OBJECTIVES

We examined associations between prenatal PM2.5 exposure and infant negative affectivity, a stable temperamental trait associated with longer-term behavioral and mental health outcomes. We also examined sex-specific effects.

METHODS

Analyses included 559 mother-infant pairs enrolled in the PRogramming of Intergenerational Stress Mechanisms (PRISM) cohort. Daily PM2.5 exposure based on geocoded residential address during pregnancy was estimated using a satellite-based spatiotemporal model. Domains of negative affectivity (Sadness, Distress to Limitations, Fear, Falling Reactivity) were assessed using the Infant Behavior Questionnaire-Revised (IBQ-R) when infants were 6 months old. Subscale scores were calculated as the mean of item-specific responses; the global Negative Affectivity (NA) score was derived by averaging the mean of the four subscale scores. Bayesian distributed lag interaction models (BDLIMs) were used to identify sensitive windows for prenatal PM2.5 exposure on global NA and its subscales, and to examine effect modification by sex.

RESULTS

Mothers were primarily racial/ethnic minorities (38% Black, 37% Hispanic), 40% had ≤12 years of education; most did not smoke during pregnancy (87%). In the overall sample, BDLIMs revealed that increased PM2.5 at mid-pregnancy was associated with higher global NA, Sadness, and Fear scores, after adjusting for covariates (maternal age, education, race/ethnicity, sex). Among boys, increased PM2.5 at early pregnancy was associated with decreased Fear scores, while exposure during late pregnancy was associated with increased Fear scores (cumulative effect estimate = 0.57, 95% CI: 0.03-1.41). Among girls, increased PM2.5 during mid-pregnancy was associated with higher Fear scores (cumulative effect estimate = 0.82, 95% CI: 0.05-1.91).

CONCLUSIONS

Prenatal PM2.5 exposure was associated with negative affectivity at age 6 months, and the sensitive windows may vary by subdomains and infant sex.

Dose-response relationships between maternal urinary cotinine and placental weight and ratio of placental weight to birth weight: The Japan Environment and Children's Study

INTRODUCTION

Studies on the relationship between maternal self-reported smoking status and placental weight report inconsistent results. This study examined the relationships between maternal urinary cotinine concentration and placental weight and the ratio of placental weight to birth weight (PW/BW ratio). The study also examined the relationship between maternal smoking status, as determined by cotinine concentration, with placental weight and with PW/BW ratio, stratified by sex of offspring.

METHODS

Our analysis used information of 91,049 mother-child pairs enrolled in the Japan Environment and Children's Study. Maternal urinary cotinine concentration was quantified (during the second or third trimester) with high-performance liquid chromatography-tandem mass spectrometry. Using restricted cubic splines, placental weight and PW/BW ratio were plotted against natural log-transformed cotinine concentration. Taking cotinine levels of <0.17 ng/mL, 0.17 to <21.5 ng/mL (natural log-transformed values, -1.77 to 3.07), and ≥21.5 ng/mL as indicative of non-smokers, passive smokers, and active smokers, respectively, the relationships between maternal smoking status and placental weight and PW/BW ratio were examined, adjusting for confounders.

RESULTS

Placental weight and PW/BW ratio increased with increasing cotinine concentration. After cotinine reached a certain concentration, the placental weight decreased in male offspring whereas it plateaued in female offspring. Compared with not smoking, active smoking during pregnancy significantly increased placental weight and PW/BW ratio.

CONCLUSION

Placental weight responded as an inverted U-shape whereas the PW/BW ratio followed a J-shape with increasing maternal urinary cotinine concentration measured during pregnancy, suggesting exposure to tobacco smoke induces a disproportionate reduction in fetal growth. The effect of tobacco smoke on placental growth varied by sex of offspring.

Sex-specific placental gene expression signatures of small for gestational age at birth

INTRODUCTION

Small for gestational age at birth (SGA), often a consequence of placental dysfunction, is a risk factor for neonatal morbidity and later life cardiometabolic diseases. There are sex differences in placental gene expression and fetal growth. Here, we investigated sex-specific associations between gene expression in human placenta measured using RNA sequencing and SGA status using data from ethnic diverse pregnant women in the NICHD Fetal Growth Studies cohort (n = 74).

METHODS

Gene expression measures were obtained using RNA-Sequencing and differential gene expression between SGA (birthweight <10th percentile) and appropriate for gestational age (AGA: ≥10th and <90th percentile) was tested separately in males (12 SGA and 27 AGA) and females (9 SGA and 26 AGA) using a weighted mean of log ratios method with adjustment for mode of delivery and ethnicity.

RESULTS

At 5% false discovery rate (FDR), we identified 40 differentially expressed genes (DEGs) related to SGA status among males (95% up- and 5% down-regulated) and 314 DEGs among females (32.5% up- and 67.5% down-regulated). Seven female-specific DEGs overlapped with known imprinted genes (AXL, CYP24A1, GPR1, PLAGL1, CMTM1, DLX5, LY6D). The DEGs in males were significantly enriched for immune response and inflammation signaling pathways whereas the DEGs in females were enriched for organ development signaling pathways (FDR<0.05). Sex-combined analysis identified no additional DEGs, rather 98% of the sex-specific DEGs were no longer significant and the remaining 2% were attenuated.

DISCUSSION

This study revealed sex-specific human placental gene expression changes and molecular pathways associated with SGA and underscored that unravelling the pathogenesis of SGA warrants consideration of fetal sex as a biological variable.

TRIAL REGISTRATION

https://www.

CLINICALTRIALS

gov, Unique identifier: NCT00912132.

Placental Insulin Receptor Transiently Regulates Glucose Homeostasis in the Adult Mouse Offspring of Multiparous Dams

In pregnancies complicated by maternal obesity and gestational diabetes mellitus, there is strong evidence to suggest that the insulin signaling pathway in the placenta may be impaired. This may have potential effects on the programming of the metabolic health in the offspring; however, a direct link between the placental insulin signaling pathway and the offspring health remains unknown. Here, we aimed to understand whether specific placental loss of the insulin receptor (InsR) has a lasting effect on the offspring health in mice. Obesity and glucose homeostasis were assessed in the adult mouse offspring on a normal chow diet (NCD) followed by a high-fat diet (HFD) challenge. Compared to their littermate controls, InsR KO^placenta offspring were born with normal body weight and pancreatic β-cell mass. Adult InsR KO^placenta mice exhibited normal glucose homeostasis on an NCD. Interestingly, under a HFD challenge, adult male InsR KO^placenta offspring demonstrated lower body weight and a mildly improved glucose homeostasis associated with parity. Together, our data show that placenta-specific insulin receptor deletion does not adversely affect offspring glucose homeostasis during adulthood. Rather, there may potentially be a mild and transient protective effect in the mouse offspring of multiparous dams under the condition of a diet-induced obesogenic challenge.

Prenatal metal(loid) mixtures and birth weight for gestational age: A pooled analysis of three cohorts participating in the ECHO program

BACKGROUND

A growing number of studies have identified both toxic and essential metals which influence fetal growth. However, most studies have conducted single-cohort analyses, which are often limited by narrow exposure ranges, and evaluated metals individually. The objective of the current study was to conduct an environmental mixture analysis of metal impacts on fetal growth, pooling data from three geographically and demographically diverse cohorts in the United States participating in the Environmental Influences on Child Health Outcomes program.

METHODS

The pooled sample (N = 1,002) included participants from the MADRES, NHBCS, and PROTECT cohorts. Associations between seven metals (antimony, cadmium, cobalt, mercury, molybdenum, nickel, tin) measured in maternal urine samples collected during pregnancy (median: 16.0 weeks gestation) and birth weight for gestational age z-scores (BW for GA) were investigated using Bayesian Kernel Machine Regression (BKMR). Models were also stratified by cohort and infant sex to investigate possible heterogeneity. Chromium and uranium concentrations fell below the limits of detection for most participants and were evaluated separately as binary variables using pooled linear regression models.

RESULTS

In the pooled BKMR analysis, antimony, mercury, and tin were inversely and linearly associated with BW for GA, while a positive linear association was identified for nickel. The inverse association between antimony and BW for GA was observed in both males and females and for all three cohorts but was strongest for MADRES, a predominantly low-income Hispanic cohort in Los Angeles. A reverse j-shaped association was identified between cobalt and BW for GA, which was driven by female infants. Pooled associations were null for cadmium, chromium, molybdenum, and uranium, and BKMR did not identify potential interactions between metal pairs.

CONCLUSIONS

Findings suggest that antimony, an understudied metalloid, may adversely impact fetal growth. Cohort- and/or sex-dependent associations were identified for many of the metals, which merit additional investigation.

Maternal, placental, and fetal distribution of titanium after repeated titanium dioxide nanoparticle inhalation through pregnancy

Epidemiological studies have associated ambient engineered nanomaterials or ultrafine particulate matter (PM_0.1), collectively referred to as nanoparticles (NPs), with adverse pregnancy outcomes including miscarriage, preterm labor, and fetal growth restriction. Evidence from non-pregnant models demonstrate that NPs can cross the lung air-blood barrier and circulate systemically. Therefore, inhalation of NPs during pregnancy leading to fetoplacental exposure has garnered attention. The purpose of this study was to evaluate the distribution of inhaled titanium dioxide nanoparticles (nano-TiO₂) from the maternal lung to maternal and fetal systemic tissues. Pregnant Sprague Dawley rats were administered whole-body exposure to filtered air or of nano-TiO₂ aerosols (9.96 ± 0.06 mg/m³) between gestational day (GD) 4 and 19. On GD 20 maternal, placental, and fetal tissues were harvested then digested for ICP-MS analysis to measure concentrations of titanium (Ti). TEM was used to visualize particle internalization by the placental syncytium. The results demonstrate the extrapulmonary distribution of Ti to various maternal organs during pregnancy. Our study found Ti accumulation in the decidua/junctional and labyrinth zones of placentas embedded in all sections of uterine horns. Further, NPs deposited in the placenta, identified by TEM, were found intracellularly within nuclear, endoplasmic reticulum, and vesicle organelles. This study identified the systemic distribution and placental accumulation of Ti after nano-TiO₂ aerosol inhalation in a pregnancy model. These findings arouse concerns for poor air quality for pregnant women and possible contributions to adverse pregnancy outcomes.

Clinicopathological study and immunohistochemical analysis of expression of annexin A5 and apelin in human placentae of gestational diabetes mellitus

BACKGROUND AND AIMS

Gestational diabetes mellitus (GDM) is one of the commonest medical complications of pregnancy. Annexin A5 (ANXA5) is a protein, found in apical surfaces of syncytiotrophoblasts, which prevents fetal and placental vascular thrombosis in GDM. Apelin is a bioactive peptide which has been linked to GDM. The aim of the present study was to correlate macroscopic as well as microscopic changes and immunohistochemical expression of ANXA5 and apelin in placentae of GDM with maternal and neonatal clinical features and also to compare the results with those in matched controls.

METHODS

This prospective observational study was undertaken for a period of one year from April 2020 to March 2021. It comprised of 42 patients of GDM. Gross features, microscopic features and intensity and grade of expression of ANXA5 and Apelin were analyzed in placentae of GDM.

RESULTS

Morphological changes detected in GDM placentae included increased immature villi (16 cases, 38%), increased syncytial knots (36, 86%), perivillous fibrin deposition (20, 48%), fibrosis of villous stroma (20, 48%), presence of nucleated red blood cells (12, 28.5%) and hypervascularity (34, 81%). The extent of histopathological changes noted in GDM placentae was significantly higher than that in matched controls. GDM placentae showed significantly reduced expression of ANXA5 and Apelin in terms of grade and intensity when compared with matched controls. Reduced expression (mild intensity) of ANXA5 was noted in 22 GDM cases (52.3%) whereas apelin expression was of weak intensity in 26 (61.9%) cases. Among GDM patients, statistically significant association was noted between ANXA5 intensity and neonatal resuscitation, apelin grade and preterm birth as well as low birth weight and apelin intensity and requirement of treatment in sick neonatal care unit.

CONCLUSION

The placental expression of the proteins, ANXA5 and Apelin, is altered in GDM though their exact pathogenetic mechanisms are yet to be understood. They can be targets for development of prophylactic and therapeutic agents in future.

Gestational hypercholesterolemia programs hepatic steatosis in a sex-specific manner in ApoE-deficient mice

Maternal hypercholesterolemia (MHC), a pathological condition characterized by an exaggerated rise in maternal serum cholesterol during pregnancy, may influence offspring hepatic lipid metabolism and increase the risk of nonalcoholic fatty liver disease (NAFLD). As NAFLD is characterized by a sexual dimorphic response, we assessed whether early-life exposure to excessive cholesterol influences the development of NAFLD in offspring and whether this occurs in a sex-specific manner. Female apoE-/- mice were randomly assigned to a control (CON) or a high cholesterol (CH; 0.15%) diet prior to breeding. At parturition, a cross-fostering approach was used to establish three groups: (1) normal cholesterol exposure throughout gestation and lactation (CON-CON); (2) excessive cholesterol exposure throughout gestation and lactation (CH-CH); and (3) excessive cholesterol exposure in the gestation period only (CH-CON). Adult male offspring (PND 84) exposed to excessive cholesterol during gestation only (CH-CON) demonstrated hepatic triglyceride (TG) accumulation and reduced lipogenic gene expression. However, male mice with a prolonged cholesterol exposure throughout gestation and lactation (CH-CH) had a similar, but not exacerbated hepatic response. Further, with the exception of higher serum TG in adult CH-CH females, evidence for a programming effect in female offspring was largely absent in comparison with males. These results indicate a sexual dimorphic response with respect to the effect of MHC on later life hepatic steatosis and highlight the gestation period as the most influential malprogramming window for hepatic lipid dysfunction in males.

Prenatal Fine Particulate Matter, Maternal Micronutrient Antioxidant Intake, and Early Childhood Repeated Wheeze: Effect Modification by Race/Ethnicity and Sex

Fine particulate matter (PM2.5) potentiates in utero oxidative stress influencing fetal development while antioxidants have potential protective effects. We examined associations among prenatal PM2.5, maternal antioxidant intake, and childhood wheeze in an urban pregnancy cohort (n = 530). Daily PM2.5 exposure over gestation was estimated using a satellite-based spatiotemporally resolved model. Mothers completed the modified Block98 food frequency questionnaire. Average energy-adjusted percentile intake of β-carotene, vitamins (A, C, E), and trace minerals (zinc, magnesium, selenium) constituted an antioxidant index (AI). Maternal-reported child wheeze was ascertained up to 4.1 ± 2.8 years. Bayesian distributed lag interaction models (BDLIMs) were used to examine time-varying associations between prenatal PM2.5 and repeated wheeze (≥2 episodes) and effect modification by AI, race/ethnicity, and child sex. Covariates included maternal age, education, asthma, and temperature. Women were 39% Black and 33% Hispanic, 36% with ≤high school education; 21% of children had repeated wheeze. Higher AI was associated with decreased wheeze in Blacks (OR = 0.37 (0.19-0.73), per IQR increase). BDLIMs identified a sensitive window for PM2.5 effects on wheeze among boys born to Black mothers with low AI (at 33-40 weeks gestation; OR = 1.74 (1.19-2.54), per µg/m3 increase in PM2.5). Relationships among prenatal PM2.5, antioxidant intake, and child wheeze were modified by race/ethnicity and sex.

Sperm Histone H3 Lysine 4 tri-methylation serves as a metabolic sensor of paternal obesity and is associated with the inheritance of metabolic dysfunction

Objective

Parental environmental exposures can strongly influence descendant risks for adult disease. How paternal obesity changes the sperm chromatin leading to the acquisition of metabolic disease in offspring remains controversial and ill-defined. The objective of this study was to assess (1) whether obesity induced by a high-fat diet alters sperm histone methylation; (2) whether paternal obesity can induce metabolic disturbances across generations; (3) whether there could be cumulative damage to the sperm epigenome leading to enhanced metabolic dysfunction in descendants; and (4) whether obesity-sensitive regions associate with embryonic epigenetic and transcriptomic profiles. Using a genetic mouse model of epigenetic inheritance, we investigated the role of histone H3 lysine 4 methylation (H3K4me3) in the paternal transmission of metabolic dysfunction. This transgenic mouse overexpresses the histone demethylase enzyme KDM1A in the developing germline and has an altered sperm epigenome at the level of histone H3K4 methylation. We hypothesized that challenging transgenic sires with a high-fat diet would further erode the sperm epigenome and lead to enhanced metabolic disturbances in the next generations.

Methods

To assess whether paternal obesity can have inter- or transgenerational impacts, and if so to identify potential mechanisms of this non-genetic inheritance, we used wild-type C57BL/6NCrl and transgenic males with a pre-existing altered sperm epigenome. To induce obesity, sires were fed either a control or high-fat diet (10% or 60% kcal fat, respectively) for 10–12 weeks, then bred to wild-type C57BL/6NCrl females fed a regular diet. F₁ and F₂ descendants were characterized for metabolic phenotypes by examining the effects of paternal obesity by sex, on body weight, fat mass distribution, the liver transcriptome, intraperitoneal glucose, and insulin tolerance tests. To determine whether obesity altered the F₀ sperm chromatin, native chromatin immunoprecipitation-sequencing targeting H3K4me3 was performed. To gain insight into mechanisms of paternal transmission, we compared our sperm H3K4me3 profiles with embryonic and placental chromatin states, histone modification, and gene expression profiles.

Results

Obesity-induced alterations in H3K4me3 occurred in genes implicated in metabolic, inflammatory, and developmental processes. These processes were associated with offspring metabolic dysfunction and corresponded to genes enriched for H3K4me3 in embryos and overlapped embryonic and placenta gene expression profiles. Transgenerational susceptibility to metabolic disease was only observed when obese F₀ had a pre-existing modified sperm epigenome. This coincided with increased H3K4me3 alterations in sperm and more severe phenotypes affecting their offspring.

Conclusions

Our data suggest sperm H3K4me3 might serve as a metabolic sensor that connects paternal diet with offspring phenotypes via the placenta. This non-DNA-based knowledge of inheritance has the potential to improve our understanding of how environment shapes heritability and may lead to novel routes for the prevention of disease. This study highlights the need to further study the connection between the sperm epigenome, placental development, and children's health.

Summary sentence

Paternal obesity impacts sperm H3K4me3 and is associated with placenta, embryonic and metabolic outcomes in descendants.

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Sperm H3K4me3 serves as a metabolic sensor of HFD-induced obesity.

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Obesity-altered sperm H3K4me3 corresponds to embryonic transcription and chromatin profiles.

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HFD- and KDM1A-induced cumulative sperm epimutations enhanced F₁ metabolic dysfunction.

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Sperm epimutations may influence placenta function inducing F₁ metabolic phenotypes.

IUGR with catch-up growth programs impaired insulin sensitivity through LRP6/IRS-1 in male rats

Intrauterine growth restriction combined with postnatal accelerated growth (CG-IUGR) could lead to long-term detrimental metabolic outcomes characterized by insulin resistance. As an indispensable co-receptor of Wnt signaling, LRP6 plays a critical role in the susceptibility of metabolic disorders. However, whether LRP6 is involved in the metabolic programing is still unknown. We hypothesized that CG-IUGR programed impaired insulin sensitivity through the impaired LRP6-mediated Wnt signaling in skeletal muscle. A CG-IUGR rat model was employed. The transcriptional and translational alterations of the components of the Wnt and the insulin signaling in the skeletal muscle of the male CG-IUGR rats were determined. The role of LRP6 on the insulin signaling was evaluated by shRNA knockdown or Wnt3a stimulation of LRP6. Compared with controls, the male CG-IUGR rats showed an insulin-resistant phenotype, with impaired insulin signaling and decreased expression of LRP6/β-catenin in skeletal muscle. LRP6 knockdown led to reduced expression of the IR-β/IRS-1 in C2C12 cell line, while Wnt3a-mediated LRP6 expression increased the expression of IRS-1 and IGF-1R but not IR-β in the primary muscle cells of male CG-IUGR rats. The impaired LRP6/β-catenin/IGF-1R/IRS-1 signaling is probably one of the critical mechanisms underlying the programed impaired insulin sensitivity in male CG-IUGR.

Does foetal gender influence maternal thyroid parameters in pregnancy?

Objective

It is unknown if foetal gender influences maternal thyroid function during pregnancy. We therefore investigated the prevalence of thyroid disorders and determined first-trimester TSH reference ranges according to gender.

Methods

A cross-sectional study involving 1663 women with an ongoing pregnancy was conducted. Twin and assisted pregnancies and l-thyroxine or antithyroid treatment before pregnancy were exclusion criteria. Serum TSH, free T4 (FT4) and thyroid peroxidase antibodies (TPOAb) were measured at median (interquartile range; IQR) 13 (11-17) weeks of gestation. Subclinical hypothyroidism (SCH) was present when serum TSH levels were >3.74 mIU/L with normal FT4 levels (10.29-18.02 pmol/L), and thyroid autoimmunity (TAI) was present when TPOAb were ≥60 kIU/L.

Results

Eight hundred and forty-seven women were pregnant with a female foetus (FF) and 816 with a male foetus (MF). In women without TAI and during the gestational age period between 9 and 13 weeks (with presumed high-serum hCG levels), median (IQR range) serum TSH in the FF group was lower than that in the MF group: 1.13 (0.72-1.74) vs 1.24 (0.71-1.98) mIU/L; P = 0.021. First-trimester gender-specific TSH reference range was 0.03-3.53 mIU/L in the FF group and 0.03-3.89 mIU/L in the MF group. The prevalence of SCH and TAI was comparable between the FF and MF group: 4.4% vs 5.4%; P = 0.345 and 4.9% vs 7.5%; P = 0.079, respectively.

Conclusions

Women pregnant with an MF have slightly but significantly higher TSH levels and a higher upper limit of the first-trimester TSH reference range, compared with pregnancies with a FF. We hypothesise that this difference may be related to higher hCG levels in women pregnant with a FF, although we were unable to measure hCG in this study. Further studies are required to investigate if this difference has any clinical relevance.