Type 2 (non-insulin-dependent) diabetes mellitus, hypertension and hyperlipidaemia (syndrome X): relation to reduced fetal growth

Parent-of-origin effects in the life-course evolution of cardiometabolic traits

AIMS/HYPOTHESIS

Cardiometabolic traits are heritable, and some display parent-of-origin effects, which indicates preferential inheritance from one parent or parental bias. Most studies of these phenomena have focused on adult populations. We aimed to investigate the heritability and parent-of-origin effects on cardiometabolic traits in a birth cohort with serial measurements to determine whether these patterns emerged early in life.

METHODS

The Pune Maternal Nutrition Study comprises a birth cohort in which offspring and parents were studied from birth and followed up for 24 years. We investigated parent-of-origin effects on cardiometabolic traits cross-sectionally at available timepoints using linear regression, and longitudinally across the life course using mixed-effect regression. Maternal and paternal effects on offspring phenotype were modelled after adjusting for age, sex and BMI. Parent-of-origin effects were calculated based on the difference between maternal and paternal effects. We also investigated these effects in another birth cohort, that of the Pune Children's Study. Genetic parent-of-origin effects were assessed using generalised estimating equations after taking the parental origin of the alleles into account.

RESULTS

Birthweight showed a maternal parent-of-origin effect. At 24 years, maternal bias was seen for some obesity-related traits for daughters, while paternal bias was seen for WHR in sons. A shift from paternal bias at 6 years to maternal bias at 24 years for the skinfold thickness was observed in daughters. Fasting glucose and lipids showed maternal bias at 6, 12 and 24 years. For fasting insulin and HOMA2-S, a negative maternal effect at 6 years transitioned to a positive one at 12 years. For HOMA2-B, a paternal effect at 6 years transitioned to a maternal one at 12 years, and this remained so at 24 years. Some of these findings were also observed in the cohort from the Pune Children's Study. Longitudinal modelling revealed stronger paternal effects over time for fasting insulin and HOMA indices but maternal effects for glucose and lipids, reflecting their cumulative effect over time. Genetic variants at the KCNQ1 locus showed a maternal parent-of-origin effect on birthweight, on HOMA2-B at 12 years, and on lipids at 6 and 12 years.

CONCLUSIONS/INTERPRETATION

Our study provides proof of concept of the existence of parent-of-origin effects on cardiometabolic traits from birth, through childhood and puberty, until adult age. Our results indicate a predominantly maternal influence on intrauterine, pubertal and reproductive-age metabolism in the offspring. While the longitudinal analysis indicated a maternal bias for the macronutrients (glucose and lipids), and a paternal bias for glucose-insulin metabolism, the cross-sectional analysis revealed a transition between parental influence across physiological stages. This dynamic relationship may have its origins in the life-history theory of evolution, and could inform strategies for primordial prevention aimed at curbing the rising burden of cardiometabolic disease. Further studies are needed to determine the mechanisms underlying such effects.

Sex differences in the effects of maternal voluntary oral Cannabis consumption on the metabolic outcomes of high-fat diet in adult offspring

BACKGROUND AND PURPOSE

Given the recent rise in Cannabis legalisation, accessibility to Cannabis and consumption have increased during pregnancy. Therefore, there could be unintended developmental consequences. The endocannabinoid system plays a key role in fetal development and later-life energy homeostasis. We explored the long-term effects of maternal voluntary Cannabis consumption on the metabolic outcomes of a high-fat diet (HFD) in adult offspring.

EXPERIMENTAL APPROACH

Pregnant mice voluntarily consumed Cannabis extract equivalent to 5 mg kg-1 day-1 Δ9-tetrahydrocannabinol (THC) from gestational day 1.5 until postnatal day (PD) 10. Pregnancy and pup outcomes and active maternal behaviour were recorded. Male and female offspring (PD49) were placed on a 12-week HFD or control diet; their weight gain, adiposity, glucose tolerance, insulin sensitivity, circulating hormones and pancreatic structure were measured.

KEY RESULTS

Perinatal Cannabis exposure (PCE) pup weight was initially reduced but restored by PD16. PCE did not influence weight gain or metabolic characteristics of male mice on a HFD. PCE female but not male offspring on a HFD had reduced accumulation of adipose tissue and lower insulin, leptin and resistin independent of body weight. PCE females on control diet also showed altered basal insulin sensitivity likely because of increased glucagon levels in parallel with reduced islets of Langerhans size and enhanced gene expression of cannabinoid 2 receptors in white adipose tissue.

CONCLUSION AND IMPLICATIONS

PCE adversely affected glycaemic control in female offspring on control diet while it mitigated HFD-induced metabolic dysfunction. This raises concerns about the long-term effects of PCE on the metabolic health of offspring.

Effects of preweaning milk allowance on long-term metabolism in Holstein heifers

Suboptimal preweaning nutrition of dairy calves has been causally associated with impaired adult metabolic health and lactation performance. However, the biological mechanisms linking early life nutrient supply and future performance remain insufficiently understood. Thus, the objective of this study was to characterize growth, reproductive performance, glucose metabolism, and the metabolic profile of growing heifers fed a restricted (RES) or an elevated (ELE) milk supply preweaning. Heifer calves (n = 86) born from a single herd of ∼120 dairy cows were blocked in pairs by the dam's parity and birth date. Within block, calves were fed an identical colostrum supply and randomly assigned to a milk replacer (MR) allowance level treatment of either 5.41 Mcal of ME in 8 L of MR/d (ELE) or 2.71 Mcal of ME in 4 L of MR/d (RES). The MR (150 g/L), containing 24% crude protein, 18% crude fat, and 45% lactose, was fed from d 2 after birth until calves were stepped down by 50% at d 49 and fully weaned at d 56. All calves were kept in individual hutches until wk 10 and had ad libitum access to fresh pelleted calf starter, chopped wheat straw, and water. Starting from wk 8, heifers from both treatments were fed and managed in the same way, and preweaning treatments were blind to caretakers. Blood samples for metabolomics analysis were collected at 330 d of age, and an insulin-modified intravenous glucose tolerance test was conducted at 370 ± 12 d of age. Heifers fed the ELE diet exhibited higher average daily gain in the preweaning period, leading to higher body weight at 70 d of age (+ 9 kg). At 330 d of age, growth advantages were no longer significant, and preweaning nutrition had no effect on age at first service, first service conception rates, age at conception, or number of services per conception. The metabolomic serum data sampled at 330 d of age revealed that carnitine, glycerolipid, and purine metabolism were predicted to be significantly affected by preweaning nutrient supply, reflecting long-term metabolic programming. At 370 d of age, during the first 20 min following the glucose infusion, blood insulin levels were greater (10.3 ng/mL vs. 7.7 ng/mL), the area under the curve for insulin tended to be greater, and insulin sensitivity was lower in RES heifers. Increasing the amount of MR fed to calves preweaning had a sustained impact on metabolic processes, but long-term differences could not be detected in growth or reproductive performance, potentially due to the low number of animals.

A human cytotrophoblast-villous endothelium-fetal organ multi-cell model and the impact on gene and protein expression in placenta cytotrophoblast, fetal hepatocytes and fetal kidney epithelial cells

Appropriate fetal growth during pregnancy requires multi-directional communication from the maternal, placental and fetal systems. Disruption in any of these signaling arms can have deleterious consequences for fetal growth and initiate developmental adaptations within fetal tissues and organs that are associated with both short- and long-term morbidities. In this proof-of-concept translational, human cell model study we aimed to identify the impacts of altered trophoblast stress response mechanisms and human insulin-like 1 growth factor ( hIGF1 ) nanoparticle gene therapy on gene and protein expression in fetal liver hepatocytes and fetal kidney epithelial cells. We utilized human cell lines: BeWo choriocarcinoma cells (trophoblast), Human Placental Micro-Vascular Endothelial Cells, and WRL68 (hepatocytes) or HEK293T/17 (kidney epithelium), in a co-culture model designed to mimic cytotrophoblast-villous endothelium-fetal organ communication. Trophoblast stress response mechanisms were increased by culturing BeWo cells in growth media without FBS. Stressed BeWo cells were also treated with a hIGF1 nanoparticle gene therapy known to mitigate cellular stress mechanisms. Stressed BeWo cells had increased expression of cellular stress mechanisms but not when IGF1 was over-expressed with a transient hIGF1 nanoparticle gene therapy. Stressed and Stressed+ hIGF1 BeWo cells had increased expression of gluconeogenesis and glycolysis rate-limiting enzymes. Gene and protein expression in fetal liver and kidney cells was not impacted by increased trophoblast stress or hIGF1 nanoparticle gene therapy. In conclusion, our data demonstrated that cytotrophoblast under stress turn on mechanisms involved in glucose production. Whether this is reflected in vivo remains uninvestigated but may represent a placental compensation mechanism in complicated pregnancies.

Fetal Growth Restriction and Its Metabolism-Related Long-Term Outcomes-Underlying Mechanisms and Clinical Implications

The developmental origins of adult disease theory support the concept that undernourished fetuses are at risk of developing metabolic syndrome due to the energy-saving 'Thrifty Phenotype'. This metabolic plasticity represents an evolutionary adaptation that allows individuals to resist the intense pressure caused by cyclically recurring periods of nutritional deprivation. A comprehensive review was conducted following an extensive literature search in the PubMed/Medline and EMBASE databases concerning reports on fetal/intrauterine growth restriction and its metabolic-related long-term outcomes. We only included articles written in English that were published before 1 July 2024. There are several underlying mechanisms and metabolic and endocrine adjustments shaped by the perinatal environment, and they all contribute to progression towards adult disease. From in utero malnutrition or other insults during the fetal period to fetal programing and postnatal catch-up growth, it is difficult to identify the exact moment when this adaptative phenomenon meant to assure fetal survival and to set children on their own physiological growth curves lose its beneficial effect, establishing the trajectory to obesity, insulin resistance, and other hallmarks of metabolic syndrome. With clinical correspondence to an altered body mass, composition, and eating behaviors, it is evident that the metabolic complications linked to FGR are intricate and arise from disturbances in several pathways and organs, but the underlying processes responsible for the long-term consequences are just starting to be understood. The lack of continuity in perinatal-to-pediatric FGR research sets the challenge of exploring new directions in future scientific opportunities. These will hopefully represent a cornerstone in the management of FGR-related metabolic disorders in children, preventing these disorders from evolving into adult disease.

Comparison of cord blood alarin levels of full-term infants according to birth weight

OBJECTIVES

To compare the cord blood alarin levels of infants in different birth weight groups with those of infants born to mothers diagnosed with gestational diabetes mellitus (GDM) who were not subgrouped according to birth weight.

METHODS

This prospective study was conducted between September 2023 and January 2024. Healthy term babies whose families agreed to participate in the study were divided into four groups according to their birth weight (small for gestational age (SGA), appropriate for gestational age (AGA) and large for gestational age (LGA)) and whether their mothers had GDM.

RESULTS

There was a significant difference between the cord blood alarin levels of the AGA and SGA groups (p=0.014). There was also a significant difference between the cord blood alarin levels of the AGA and GDM groups (p=0.012). However, the cord blood alarin levels of the LGA group (whose mothers did not have GDM) were similar to those of the AGA group (p=0.394).

CONCLUSIONS

We found evidence that alarin levels in umbilical cord blood are associated with low birth weight and GDM.

Rare variant associations with birth weight identify genes involved in adipose tissue regulation, placental function and insulin-like growth factor signalling

Investigating the genetic factors influencing human birth weight may lead to biological insights into fetal growth and long-term health. We report analyses of rare variants that impact birth weight when carried by either fetus or mother, using whole exome sequencing data in up to 234,675 participants. Rare protein-truncating and deleterious missense variants are collapsed to perform gene burden tests. We identify 9 genes; 5 with fetal-only effects on birth weight, 1 with maternal-only effects, 3 with both, and observe directionally concordant associations in an independent sample. Four of the genes were previously implicated by GWAS of birth weight. IGF1R and PAPPA2 (fetal and maternal-acting) have known roles in insulin-like growth factor bioavailability and signalling. PPARG, INHBE and ACVR1C (fetal-acting) are involved in adipose tissue regulation, and the latter two also show associations with favourable adiposity patterns in adults. We highlight the dual role of PPARG (fetal-acting) in adipocyte differentiation and placental angiogenesis. NOS3 (fetal and maternal-acting), NRK (fetal), and ADAMTS8 (maternal-acting) have been implicated in placental function and hypertension. To conclude, our analysis of rare coding variants identifies regulators of fetal adipose tissue and fetoplacental angiogenesis as determinants of birth weight, and further evidence for the role of insulin-like growth factors.

Development of a new data management system for the study of the gut microbiome of children who are small for their gestational age

Microbiome studies aim to answer the following questions: which organisms are in the sample and what is their impact on the patient or the environment? To answer these questions, investigators have to perform comparative analyses on their classified sequences based on the collected metadata, such as treatment, condition of the patient, or the environment. The integrity of sequences, classifications, and metadata is paramount for the success of such studies. Still, the area of data management for the preliminary study results appears to be neglected. Here, we present the development of MetagenomicsDB (http://github.com/IOB-Muenster/MetagenomicsDB; accessed 2024/12/18), a central data management system for the study of the gut microbiome in children who are small for their gestational age (SGA). Our system provided more flexibility to conduct study-specific analyses and to integrate specific external resources than existing and necessarily more generic solutions. It supports short or long read data produced by virtually any sequencing instrument targeting (parts of) popular marker genes, such as the 16S rRNA gene and its variable regions. Classifications of these reads from the MetaG and Kraken 2 software are supported. The main goals of the system are to store the pre-computed study data securely under concurrent load and to make downstream analyses accessible to all researchers, regardless of programming proficiency. Thus, after initial plausibility checks on the input data to reduce human error, data are stored in a relational database and can be continuously updated over the whole life time of the study. We used a modular approach for MetagenomicsDB with comprehensive tests verifying the expected behavior and extensively described the underlying rational which allows users to adapt the system to their needs. We advocate the use of MetagenomicsDB as the backend for a graphical web interface. We showcase the potential of this approach at the example of our study on SGA children (http://www.bioinformatics.uni-muenster.de/tools/metagenomicsDB; accessed 2024/12/02). Without restrictions caused by the level of programming proficiency, our team members could explore the study data and optionally filter them using the graphical interface, before exporting the data in a format directly suitable for external normalization of read counts and statistical analyses. Study results could be conveniently and transparently shared with the public, as demonstrated here. Links to external resources facilitated literature search with regard to the SGA condition and assessments of the potential pathogenicity of taxa. Since different users will have different demands regarding features, data security, and web environments, we provide our implementation of the web interface as a visual example. By providing users with the MetagenomicsDB backend which constitutes the major part of the system, we ensure that custom development can be finished in a reasonable amount of time. We report our endeavors in order to motivate the application of data management systems at the scale of single studies in microbiome research.

Children born to subfertile couples, how are they doing? Evidence from research

More than 10 million children have been born with assisted reproductive technology (ART) as we begin to enter the third generation of individuals conceived by ART. Here we summarise key messages from an enlarging body of literature regarding their health. Earlier research had pointed towards increases in perinatal, neonatal and neurological risks, such as preterm birth, low birth weight, congenital malformations and cerebral palsy. Many of these risks have continued to persist in most recent work but have shown reduction. Newer research proposes long-term cardiometabolic and endocrine concerns. Fortunately, most reports conclude there is little or no risk of increased childhood malignancy or abnormal neurodevelopment. Moving forward, new research may benefit from changes in comparator groups and a better understanding of infertility per se in ART, and the confounding role it probably plays in many of the known risk associations, to reliably scan the horizon for health threats for individuals born after ART.

Maternal Low-Protein Diet During Nursing Leads to Glucose-Insulin Dyshomeostasis and Pancreatic-Islet Dysfunction by Disrupting Glucocorticoid Responsiveness in Male Rats

Both perinatal malnutrition and elevated glucocorticoids are pivotal triggers of the growing global pandemic of metabolic diseases. Here, we studied the effects of metabolic stress responsiveness on glucose-insulin homeostasis and pancreatic-islet function in male Wistar offspring whose mothers underwent protein restriction during lactation. During the first two weeks after delivery, lactating dams were fed a low-protein (4% protein, LP group) or normal-protein diet (22.5% protein, NP group). At 90 days of age, male rat offspring were challenged with food deprivation (72 h of fasting), intracerebroventricular (icv) injection of dexamethasone (2 µL, 2.115 mmol/L) or chronic intraperitoneal injection of dexamethasone (1 mg/kg body weight/5 days). Body weight, food intake, intravenous glucose tolerance test (ivGTT) results, insulin secretion and biochemical parameters were assessed. LP rats did not display significant metabolic changes after long-term starvation (p > 0.05) or under the central effect of dexamethasone (p = 0.999). Chronic dexamethasone induced rapid hyperglycemia (~1.2-fold, p < 0.001) and hyperinsulinemia (NP: 65%; LP: 216%; p < 0.001), decreased insulin sensitivity (NP: ~2-fold; LP: ~4-fold; p < 0.001), reduced insulinemia (20%) and increased glycemia (35%) only in NP rats under ivGTT conditions (p < 0.001). Glucose and acetylcholine insulinotropic effects, as well as the muscarinic receptor antagonist response, were reduced by chronic dexamethasone only in pancreatic islets from NP rats (p < 0.05). The direct effect of dexamethasone on pancreatic islets reduced insulin secretion (NP: 60.2%, p < 0.001; LP: 33.8%, p < 0.001). Peripheral glucose-insulin dyshomeostasis and functional failure of pancreatic islets in LP rats, as evidenced by an impaired acute and chronic response to metabolic stress, may be due to excessive corticosterone action as a long-term consequence.

Protracted maternal malnutrition induces aberrant changes in maternal uterine artery hemodynamics and the metabolic profiles of the dam and neonate

Malnutritional stress during gestation is a well-established driver of metabolic disfunction in offspring. Extended exposure to malnutrition requires metabolic plasticity as the animal shifts toward a catabolic state. In this paper we demonstrate the influence of malnutrition throughout gestation on uterine artery hemodynamics and the metabolism of the dam and neonate. We hypothesized that gestational malnutrition reduces blood flow of the maternal uterine artery and regulates the metabolic profile of the dam and offspring. Further, the combination of these factors consequently influences the concentration of metabolites in the cerebrospinal fluid of the neonate at birth. To test our hypotheses, pregnant cows caring a single female fetus were assigned to treatments by age and body condition score to one of three individually-fed dietary treatments: Underfed, Control, or Overfed throughout gestation. Uterine blood flow was measured via transrectal Doppler ultrasonography in late gestation. Blood samples were collected from dams throughout gestation, and blood and cerebrospinal fluid were collected from neonates at birth to analyze concentration of metabolites. In the current report, we reveal that maternal malnutrition regulates uterine artery hemodynamics and the maternal metabolic profile throughout gestation. This is the first report to demonstrate that maternal undernutrition leads to an increase in the concentration of urea nitrogen in neonates. Finally, a concentration gradient of metabolites from the dam to neonatal cerebrospinal fluid was observed, which may have potential implications for central nervous system development. These findings not only illustrate the complexity of the maternal-to-fetal interaction required to support the growth of the fetus and homeostasis of the dam but also reveals a novel avenue for investigating the influence of protracted maternal malnutrition on metabolic pathway preferences in offspring. Moreover, these findings are of paramount importance in the development of intervention strategies for morbid neonates.

Metformin and small for gestational age babies: findings of a randomised placebo-controlled clinical trial of metformin in gestational diabetes (EMERGE)

AIMS/HYPOTHESIS

Gestational diabetes mellitus (GDM) is associated with adverse perinatal outcomes because of suboptimal glucose management and glucose control and excessive weight gain. Metformin can offset these factors but is associated with small for gestational age (SGA) infants. We sought to identify risk factors for SGA infants, including the effect of metformin exposure on SGA status.

METHODS

In this prespecified secondary analysis of the EMERGE trial, which evaluated the effectiveness of metformin vs placebo in treating GDM and found reduced gestational weight gain and longer time to insulin initiation with metformin use, we included women with a live-born infant and known infant birthweight and gestational age at delivery. We compared the numbers of SGA infants in both groups and explored baseline predictive factors to help identify those at highest risk of delivering an SGA infant.

RESULTS

Baseline maternal characteristics were similar between SGA and non-SGA pregnancies. On multivariable-adjusted regression, no baseline maternal variables were associated with SGA status. Mothers of SGA infants were more likely to develop pre-eclampsia or gestational hypertension (18.2% vs 2.0%, p=0.001; 22.7% vs 5.4%, p=0.005, respectively); after multivariable adjustment, pre-eclampsia was positively associated with SGA status). Among SGA pregnancies, important perinatal outcomes including preterm birth, Caesarean delivery and neonatal care unit admission did not differ between the metformin and placebo groups (20.0% vs 14.3%, p=1.00; 50.0% vs 28.6%, p=0.25; 13.3% vs 42.9%, p=0.27, respectively).

CONCLUSIONS/INTERPRETATION

Pre-eclampsia was strongly associated with SGA infants. Metformin-exposed SGA infants did not display a more severe SGA phenotype than infants treated with placebo.

TRIAL REGISTRATION

Clinical Trials.gov NCT02980276; EudraCT number: 2016-001644-19.

Long term links between maternal diet during pregnancy and offspring health

The developmental origins of health and disease hypothesis propose that lifelong health is programmed during foetal development, in utero. The world's population is ageing due to increased longevity but expanding morbidity and the associated burden on health systems around the planet, are associated with this. Consequently, resources are strained and spent largely on treating patients rather than preventing chronic diseases at their source. Research on early life exposures, starting in the womb, is needed to identify new potential biomarkers linked with the development of chronic diseases during adulthood. Evidence from maternal-offspring cohorts investigating associations between pregnancy exposures and childhood metabolic health is reviewed (The GUSTO study in Singapore, the Copenhagen Prospective Studies on Asthma in Childhood, a mother-child cohort in rural Gambia, the MINIMat study in Bangladesh, The Iodine Status in Pregnancy and Offspring Health Cohort in China, the OBESO cohort in Mexico, the Pune Nutrition study in India, The Reus-Tarragona Birth Cohort study in Spain). Collectively, evidence from prospective observational studies, randomised controlled trials and animal studies, supports the hypothesis that maternal diet, lifestyle and nutritional status during pregnancy are associated with childhood metabolic health in the offspring. However, the evidence is scant and further research is needed.

Body Composition and Metabolism in Adults With Molecularly Confirmed Silver-Russell Syndrome

CONTEXT

Low birth weight, as seen in Silver-Russell syndrome (SRS), is associated with later cardiometabolic disease. Data on long-term outcomes and adult body composition in SRS are limited.

OBJECTIVE

To evaluate body composition and metabolic health in adults with SRS.

METHODS

This was an observational study of 25 individuals with molecularly confirmed SRS, aged ≥ 18 years, from research facilities across the UK. Body composition and metabolic health were assessed at a single appointment. Individuals with SRS were compared with unaffected men and women (from the Southampton Women's Survey [SWS]). Fat mass, lean mass, bone mineral density (BMD), blood pressure, lipids, and blood glucose were measured.

RESULTS

Twenty-five adults with SRS were included (52% female). The median age was 32.9 years (range, 22.0 to 69.7). Fat percentage was greater in the SRS group than the SWS cohort (44.1% vs 30.3%, P < .001). Fat mass index was similar (9.6 vs 7.8, P = .3). Lean mass percentage (51.8% vs 66.2%, P < .001) and lean mass index (13.5 kg/m2 vs 17.3 kg/m2, P < .001) were lower in the SRS group than the SWS cohort. BMD was lower in the SRS group than the SWS cohort (1.08 vs 1.24, P < .001; all median values). Total cholesterol was ≥ 5 mmol/L in 52.0%. Triglyceride levels were ≥ 1.7 mmol/L in 20.8%. Fasting blood glucose levels were ≥ 6.1 mmol/L in 25.0%. Hypertension was present in 33.3%.

CONCLUSION

Adults with SRS have an unfavorable body composition and predisposition to cardiometabolic disease. These results support the need for a health surveillance strategy to mitigate adverse outcomes.

A novel scale for assessing the risk of low birthweight: Birthweight questionnaire

BACKGROUND

The birthweight of a newborn is critical to their health, development, and well-being. Previous studies that used maternal characteristics to predict birthweight did not employ a harmonised scale to assess the risk of low birthweight (LBW).

OBJECTIVE

The goal of this study was to develop a new instrument that uses items on a uniform scale to assess the risk of an LBW in a pregnant woman.

METHODS

Item response theory was employed to evaluate a similar existing scale, and some weaknesses were identified.

RESULTS

Based on the observed weaknesses of the existing scale, a new uniform scale was developed, which is a 3-point Likert scale consisting of seven items.

CONCLUSION

The scale, termed birthweight questionnaire, is a valuable tool for collecting data that could assist in assessing the risk of an LBW at every stage of pregnancy.

Maternal diet during pregnancy and adaptive changes in the maternal and fetal pancreas have implications for future metabolic health

Fetal and neonatal development is a critical period for the establishment of the future metabolic health and disease risk of an individual. Both maternal undernutrition and overnutrition can result in abnormal fetal organ development resulting in inappropriate birth size, child and adult obesity, and increased risk of Type 2 diabetes and cardiovascular diseases. Inappropriate adaptive changes to the maternal pancreas, placental function, and the development of the fetal pancreas in response to nutritional stress during pregnancy are major contributors to a risk trajectory in the offspring. This interconnected maternal-placental-fetal metabolic axis is driven by endocrine signals in response to the availability of nutritional metabolites and can result in cellular stress and premature aging in fetal tissues and the inappropriate expression of key genes involved in metabolic control as a result of long-lasting epigenetic changes. Such changes result is insufficient pancreatic beta-cell mass and function, reduced insulin sensitivity in target tissues such as liver and white adipose and altered development of hypothalamic satiety centres and in basal glucocorticoid levels. Whilst interventions in the obese mother such as dieting and increased exercise, or treatment with insulin or metformin in mothers who develop gestational diabetes, can improve metabolic control and reduce the risk of a large-for-gestational age infant, their effectiveness in changing the adverse metabolic trajectory in the child is as yet unclear.

The impact of glycosylated hemoglobin and 75-g oral glucose tolerance test glucose levels on birthweight percentile

OBJECTIVE

Our research objective was to validate and contribute further evidence to the studies regarding large for gestational age and birthweight percentile by examining oral glucose tolerance test and glycosylated hemoglobin levels in both healthy women and those with gestational diabetes mellitus.

METHODS

This retrospective cohort study was conducted at a tertiary care hospital involving 106 women who delivered at gestational week 36 or later between February 2022 and February 2023. Maternal, obstetric, and neonatal data were collected from the participant's medical records. Large for gestational age and non-large for gestational age groups were compared. Correlation analysis was used to determine associations among oral glucose tolerance test, glycosylated hemoglobin levels, and the birthweight percentile.

RESULTS

Mothers of neonates in the large for gestational age category had higher body mass indexes before pregnancy (p=0.002) and delivery (p=0.003), as well as a higher incidence of gestational diabetes mellitus (p=0.027). Mothers of male large for gestational age infants had higher fasting plasma glucose and glycosylated hemoglobin levels compared to male non-large for gestational age infants (p=0.007 and p=0.004, respectively). There was a weak positive correlation between fasting plasma glucose levels and birthweight percentile in the overall group (r=0.342, p<0.006). Further analysis by gender showed a weak positive correlation between birthweight percentile and fasting plasma glucose and glycosylated hemoglobin values in male newborns (r=0.393, p=0.004 and r=0.373, p=0.006, respectively).

CONCLUSION

Our study has established a clear association between the birthweight percentile in male infants and the levels of glycosylated hemoglobin and fasting plasma glucose measured during oral glucose tolerance test. It is imperative to devise potential strategies aimed at achieving optimal glycosylated hemoglobin and fasting plasma glucose parameters to effectively reduce the frequency of large for gestational age in male infants.

Trimester-specific association between fetal growth and physical activity in pregnant women: total physical activity vs moderate-to-vigorous exercise

OBJECTIVE

To investigate the trimester-specific associations between maternal total physical activity level vs moderate-to-vigorous exercise and fetal growth disorders.

METHODS

We analyzed 2062 mother-neonate pairs participating in the longitudinal China Medical University Birth Cohort Study. The Pregnancy Physical Activity Questionnaire was used to assess the physical activity level of women during the three trimesters. A higher level of total physical activity was defined as meeting or exceeding the cohort-specific 75th percentile, and a higher level of exercise was defined according to the Physical Activity Guidelines for Americans. Fetal growth disorder was defined as small-for-gestational age (SGA) or large-for-gestational age (LGA) at birth.

RESULTS

Of the neonates included in this study, 7.1% were SGA and 15.5% were LGA. A higher level of total physical activity during the first trimester (adjusted relative risk (aRR), 0.62 (95% CI, 0.42-0.91)) and second trimester (aRR, 0.62 (95% CI, 0.41-0.95)) was associated with a lower risk of SGA, and a higher level of total physical activity during the third trimester was associated with a lower risk of LGA (aRR, 0.73 (95% CI, 0.54-0.97)). When analyzing physical activity by subtype, a higher level of occupational physical activity during the first and second trimesters was associated negatively with SGA risk, and higher levels of occupational and low-intensity physical activity during the first trimester were associated negatively with LGA risk. No significant association was found between maternal adherence to the Physical Activity Guidelines for Americans and risk of fetal growth disorders.

CONCLUSIONS

A higher total physical activity level during the first and second trimesters was associated with a decreased risk of SGA, whereas a higher total physical activity level in the third trimester was associated with a decreased risk of LGA. Pregnant women should be advised to increase their total physical activity levels instead of focusing on engaging in only moderate-to-vigorous exercise. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Small for gestational age: concept, diagnosis and neonatal characterization, follow-up and recommendations

Newborns who do not reach a weight appropriate for their gestational age and sex can be classified in different ways. This article defines the concepts of small for gestational age (SGA) and intrauterine growth restriction, as well as the underlying causes of these conditions, with the goal of establishing consensus definitions for these patients, in whom treatment with growth hormone throughout childhood may be indicated and who may be at risk of developing endocrine or metabolic disorders in puberty and adulthood. Most SGA children experience spontaneous catch-up growth that is usually completed by age 2 years. In SGA children who remain short, treatment with recombinant human growth hormone is effective, increasing adult height. Small for gestational age infants with rapid catch-up growth and marked weight gain are at increased risk of premature adrenarche, early puberty, polycystic ovary syndrome (girls), insulin resistance and obesity, all of which are risk factors for type 2 diabetes and metabolic syndrome in adulthood. The SGA status can affect different areas of neurodevelopment and manifest at different stages in life; neurodevelopmental outcomes are better in SGA infants with spontaneous catch-up growth. Due to the potential risks associated with SGA, adequate characterization of these patients at birth is imperative, as it allows initiation of appropriate follow-up and early detection of abnormalities.

Efficacy of Human Recombinant Growth Hormone in Females of a Non-Obese Hyperglycemic Mouse Model after Birth with Low Birth Weight

We examined whether the administration of growth hormone (GH) improves insulin resistance in females of a non-obese hyperglycemic mouse model after birth with low birth weight (LBW), given that GH is known to increase muscle mass. The intrauterine Ischemia group underwent uterine artery occlusion for 15 min on day 16.5 of gestation. At 4 weeks of age, female mice in the Ischemia group were divided into the GH-treated (Ischemia-GH) and non-GH-treated (Ischemia) groups. At 8 weeks of age, the glucose metabolism, muscle pathology, and metabolome of liver were assessed. The insulin resistance index improved in the Ischemia-GH group compared with the Ischemia group (p = 0.034). The percentage of type 1 muscle fibers was higher in the Ischemia-GH group than the Ischemia group (p < 0.001); the muscle fiber type was altered by GH. In the liver, oxidative stress factors were reduced, and ATP production was increased in the Ischemia-GH group compared to the Ischemia group (p = 0.014), indicating the improved mitochondrial function of liver. GH administration is effective in improving insulin resistance by increasing the content of type 1 muscle fibers and improving mitochondrial function of liver in our non-obese hyperglycemic mouse model after birth with LBW.

Increased hepatic glucose production with lower oxidative metabolism in the growth-restricted fetus

Fetal growth restriction (FGR) is accompanied by early activation of hepatic glucose production (HGP), a hallmark of type 2 diabetes (T2D). Here, we used fetal hepatic catheterization to directly measure HGP and substrate flux in a sheep FGR model. We hypothesized that FGR fetuses would have increased hepatic lactate and amino acid uptake to support increased HGP. Indeed, FGR fetuses compared with normal (CON) fetuses had increased HGP and activation of gluconeogenic genes. Unexpectedly, hepatic pyruvate output was increased, while hepatic lactate and gluconeogenic amino acid uptake rates were decreased in FGR liver. Hepatic oxygen consumption and total substrate uptake rates were lower. In FGR liver tissue, metabolite abundance, 13C-metabolite labeling, enzymatic activity, and gene expression supported decreased pyruvate oxidation and increased lactate production. Isolated hepatocytes from FGR fetuses had greater intrinsic capacity for lactate-fueled glucose production. FGR livers also had lower energy (ATP) and redox state (NADH/NAD+ ratio). Thus, reduced hepatic oxidative metabolism may make carbons available for increased HGP, but also produces nutrient and energetic stress in FGR liver. Intrinsic programming of these pathways regulating HGP in the FGR fetus may underlie increased HGP and T2D risk postnatally.

Rare variant associations with birth weight identify genes involved in adipose tissue regulation, placental function and insulin-like growth factor signalling

Investigating the genetic factors influencing human birth weight may lead to biological insights into fetal growth and long-term health. Genome-wide association studies of birth weight have highlighted associated variants in more than 200 regions of the genome, but the causal genes are mostly unknown. Rare genetic variants with robust evidence of association are more likely to point to causal genes, but to date, only a few rare variants are known to influence birth weight. We aimed to identify genes that harbour rare variants that impact birth weight when carried by either the fetus or the mother, by analysing whole exome sequence data in UK Biobank participants. We annotated rare (minor allele frequency <0.1%) protein-truncating or high impact missense variants on whole exome sequence data in up to 234,675 participants with data on their own birth weight (fetal variants), and up to 181,883 mothers who reported the birth weight of their first child (maternal variants). Variants within each gene were collapsed to perform gene burden tests and for each associated gene, we compared the observed fetal and maternal effects. We identified 8 genes with evidence of rare fetal variant effects on birth weight, of which 2 also showed maternal effects. One additional gene showed evidence of maternal effects only. We observed 10/11 directionally concordant associations in an independent sample of up to 45,622 individuals (sign test P=0.01). Of the genes identified, IGF1R and PAPPA2 (fetal and maternal-acting) have known roles in insulin-like growth factor bioavailability and signalling. PPARG, INHBE and ACVR1C (all fetal-acting) have known roles in adipose tissue regulation and rare variants in the latter two also showed associations with favourable adiposity patterns in adults. We highlight the dual role of PPARG in both adipocyte differentiation and placental angiogenesis. NOS3, NRK, and ADAMTS8 (fetal and maternal-acting) have been implicated in both placental function and hypertension. Analysis of rare coding variants has identified regulators of fetal adipose tissue and fetoplacental angiogenesis as determinants of birth weight, as well as further evidence for the role of insulin-like growth factors.

Fetal growth assessed via ultrasound in relation to maternal HIV infection status and antiretroviral regimens

OBJECTIVE

To evaluate effects of maternal HIV and antiretroviral treatment (ART) on intrauterine fetal growth.

DESIGN

Prospective cohort studies of HIV and ZIKA infection among women living with HIV (WLHIV) and women not living with HIV (WNLHIV) conducted in Brazil and the US from 2016 to 2020.

METHODS

We evaluated fetal growth via repeated ultrasounds and calculated z scores for fetal growth measures using Intergrowth-21st standards among women with singleton pregnancies. Adjusted linear mixed models were fit for each fetal growth z score by HIV status. Among WLHIV, we compared fetal growth z scores by the most common maternal ART regimens, stratified by timing of ART initiation.

RESULTS

We included 166 WLHIV and 705 WNLHIV; none had Zika infection. The z scores were similar for WLHIV and WNLHIV for femur length (latest third trimester median = 1.08) and estimated fetal weight (median ≈0.60); adjusted mean differences in fetal weight z scores by HIV status were less than 0.1 throughout gestation. Other fetal growth measurements were lower for WLHIV than WNLHIV early in gestation but increased more rapidly over gestation. Among WLHIV not on ART at conception, adjusted mean z scores were generally similar across regimens initiated during pregnancy but somewhat lower for atazanavir-based regimens for biparietal diameter compared with efavirenz-based or raltegravir-based regimens. Among WLHIV on ART at conception, mean z scores were similar across ART regimens.

CONCLUSION

Within our cohorts, fetal growth was lower in WLHIV than WNLHIV early in gestation but similar by the end of gestation, which is reassuring. Among WLHIV, fetal growth measures were generally similar across ART regimens evaluated.

Weight gain during nutritional rehabilitation post-childhood malnutrition may influence the associations between adulthood desaturases activity and anthro-cardiometabolic risk factors

BACKGROUNDS & AIMS

Childhood malnutrition is a major global health problem with long-term sequelae, including non-communicable diseases (NCDs). Mechanisms are unknown but may involve metabolic programming, resulting from "short-term" solutions to optimise survival by compromising non-priority organs. As key players in lipid metabolism, desaturases have been shown to be predictive of NCDs. We hypothesised that the association between specific desaturase activities and NCD risk determinants (including body composition, serum glucose, insulin levels, and blood pressure) are influenced by childhood post-malnutrition weight gain.

METHODS

278 Afro-Caribbean adults with well-documented clinical history of severe malnutrition in childhood were studied. Extensive metabolic analyses including body composition (DXA), fasting serum glucose and lipidomics (n = 101), and fasting serum insulin (n = 83) were performed in malnutrition survivors and matched community controls (n = 90). Established lipid ratios were used as proxies of desaturase activities: CE 16:1/CE 16:0 for stearoyl-CoA desaturase (SCD1), LysoPC 20:4/20:3 for fatty acid desaturase 1 (FADS1), and LysoPC 20:3/18:2 for FADS2.

RESULTS

Compared to community controls, adult malnutrition survivors (mean ± SD) age 28.3 ± 7.8 and BMI 23.6 ± 5.2 had higher SCD1 and FADS1 activity, (B ± SE) 0.07 ± 0.02 and 0.7 ± 0.08, respectively, but lower FADS2 activities (B ± SE) -0.05 ± 0.01, adjusted for sex and age (p < 0.0005). SCD1 was positively associated with adult BMI and body fat percentage, and negatively associated with lean mass and height. Stratification based on weight gain during nutritional rehabilitation among malnutrition survivors might signal the potential associations between weight gain during that critical period, desaturase activities, and some of adult metabolic parameters, with the lowest tertiles (slowest catch-up weight gain) performing more similarly to controls.

CONCLUSIONS

In adult survivors of early-life severe acute malnutrition, desaturase activity is associated with markers of NCD risk, especially adiposity. These associations seem to be strengthened by faster weight gain during nutritional rehabilitation.

Prenatal Exposure to Cannabis: Effects on Childhood Obesity and Cardiometabolic Health

PURPOSE OF REVIEW

To consolidate information on the obesogenic and cardiometabolic effects of prenatal exposure to cannabis.

RECENT FINDINGS

A PubMed search strategy updated from January 1, 2014, through 14 June 2023, produced a total of 47 epidemiologic studies and 12 animal studies. Prenatal exposure to cannabis is consistently associated with small for gestational age and low birth weight. After birth, these offspring gain weight rapidly and have increased adiposity and higher glucose (fat mass percentage) in childhood. More preclinical and prospective studies are needed to deepen our understanding of whether these associations vary by sex, dose, timing, and composition of cannabis (e.g., ratio of delta-Δ9-tetrahydrocannabinol [Δ9-THC] to cannabidiol [CBD]). Addressing these gaps may help to solidify causality and identify intervention strategies. Based on the available data, clinicians and public health officials should continue to caution against cannabis use during pregnancy to limit its potential obesogenic and adverse cardiometabolic effects on the offspring.

Partitioning genetic effects on birthweight at classical human leukocyte antigen loci into maternal and fetal components, using structural equation modelling

BACKGROUND

Single nucleotide polymorphisms in the human leukocyte antigen (HLA) region in both maternal and fetal genomes have been robustly associated with birthweight (BW) in previous genetic association studies. However, no study to date has partitioned the association between BW and classical HLA alleles into maternal and fetal components.

METHODS

We used structural equation modelling (SEM) to estimate the maternal and fetal effects of classical HLA alleles on BW. Our SEM leverages the data structure of the UK Biobank (UKB), which includes ∼270 000 participants' own BW and/or the BW of their firstborn child.

RESULTS

We show via simulation that our model yields asymptotically unbiased estimates of the maternal and fetal allelic effects on BW and appropriate type I error rates, in contrast to simple regression models. Asymptotic power calculations show that we have sufficient power to detect moderate-sized maternal or fetal allelic effects of common HLA alleles on BW in the UKB. Applying our SEM to imputed classical HLA alleles and own and offspring BW from the UKB replicated the previously reported association at the HLA-C locus and revealed strong evidence for maternal (HLA-A*03:01, B*35:01, B*39:06, P <0.001) and fetal allelic effects (HLA-B*39:06, P <0.001) of non-HLA-C alleles on BW.

CONCLUSIONS

Our model yields asymptotically unbiased estimates, appropriate type I error rates and appreciable power to estimate maternal and fetal effects on BW. These novel allelic associations between BW and classical HLA alleles provide insight into the immunogenetics of fetal growth in utero.

Development of Porcine Accessory Sex Glands

Accessory sex glands are recognized as targets of human disease and may have roles in reproductive success in livestock. The current experiments evaluated the influences of endogenous steroids on the development of porcine accessory sex glands, primarily in the neonatal period. When the aromatase inhibitor, letrozole, was used to inhibit the production of endogenous estrogens in the postnatal interval, growth of the seminal vesicles, prostate, and bulbourethral glands was stimulated. The weights of seminal vesicles, prostate, and bulbourethral glands approximately doubled at 6.5 weeks of age when the reduction in endogenous estrogens began at 1 week of age (p < 0.01). However, by 20 and 40 weeks of age, the weights of accessory sex glands were similar between the letrozole-treated boars and the vehicle-treated littermates indicating the growth stimulation was a transient effect when the treatment interval was short. The presence of both classical nuclear estrogen receptors and the G protein-coupled estrogen receptor in neonatal accessory sex glands indicated multiple signaling pathways might mediate the growth inhibition by endogenous estrogens. The absence of a detectable response when the classical estrogen receptors were blocked with fulvestrant (or when the androgen receptor was blocked with flutamide) suggests that endogenous estrogens act through the G protein-coupled estrogen receptor to inhibit the development of accessory sex glands during this neonatal to early juvenile interval.

Gestational Caloric Restriction Alters Adipose Tissue Methylome and Offspring's Metabolic Profile in a Swine Model

Limited nutrient supply to the fetus results in physiologic and metabolic adaptations that have unfavorable consequences in the offspring. In a swine animal model, we aimed to study the effects of gestational caloric restriction and early postnatal metformin administration on offspring's adipose tissue epigenetics and their association with morphometric and metabolic variables. Sows were either underfed (30% restriction of total food) or kept under standard diet during gestation, and piglets were randomly assigned at birth to receive metformin (n = 16 per group) or vehicle treatment (n = 16 per group) throughout lactation. DNA methylation and gene expression were assessed in the retroperitoneal adipose tissue of piglets at weaning. Results showed that gestational caloric restriction had a negative effect on the metabolic profile of the piglets, increased the expression of inflammatory markers in the adipose tissue, and changed the methylation of several genes related to metabolism. Metformin treatment resulted in positive changes in the adipocyte morphology and regulated the methylation of several genes related to atherosclerosis, insulin, and fatty acids signaling pathways. The methylation and gene expression of the differentially methylated FASN, SLC5A10, COL5A1, and PRKCZ genes in adipose tissue associated with the metabolic profile in the piglets born to underfed sows. In conclusion, our swine model showed that caloric restriction during pregnancy was associated with impaired inflammatory and DNA methylation markers in the offspring's adipose tissue that could predispose the offspring to later metabolic abnormalities. Early metformin administration could modulate the size of adipocytes and the DNA methylation changes.

Early life corticosteroid overexposure: Epigenetic and fetal origins of adult diseases

The relationship between events occurring during intrauterine development and later-life predisposition to long-term disease, has been described. The fetus responds to excess intrauterine exposure to high levels of corticosteroids, modifying their physiological development and stopping their growth. Fetal exposure to elevated levels of either endogenous (alterations in fetal hypothalamic-pituitary-adrenal axis) or synthetic corticosteroids, is one model of early-life adversity; to developing adult disease. At the molecular level, there are transcriptional changes in metabolic and growth pathways. Epigenetic mechanisms participate in transgenerational inheritance, not genomic. Exposures that change 11β-hydroxysteroid dehydrogenase type 2 enzyme methylation status in the placenta can result in transcriptional repression of the gene, causing the fetus to be exposed to higher levels of cortisol. More precise diagnosis and management of antenatal corticosteroids for preterm birth, would potentially decrease the risk of long-term adverse outcomes. More studies are needed to understand the potential roles of factors to alter fetal corticosteroid exposure. Long-term infant follow-up is required to determine whether methylation changes in placenta may represent useful biomarkers of later disease risk. This review, summarize recent advances in the programming of fetal effects of corticosteroid exposure, the role of corticosteroids in epigenetic gene regulation of placental 11β-hydroxysteroid dehydrogenase type 2 enzyme expression and transgenerational effects.

The fascinating theory of fetal programming of adult diseases: A review of the fundamentals of the Barker hypothesis

The theory of fetal programming of adult diseases was first proposed by David J.P. Barker in the eighties of the previous century, to explain the higher susceptibility of some people toward the development of ischemic heart disease. According to his hypothesis, poor maternal living conditions during gestation represent an important risk factor for the onset of atherosclerotic heart disease later in life. The analysis of the early phases of fetal development is a fundamental tool for the risk stratification of children and adults, allowing the identification of susceptible or resistant subjects to multiple diseases later in life. Here, we provide a narrative summary of the most relevant evidence supporting the Barker hypothesis in multiple fields of medicine, including neuropsychiatric disorders, such as Parkinson disease and Alzheimer disease, kidney failure, atherosclerosis, coronary heart disease, stroke, diabetes, cancer onset and progression, metabolic syndrome, and infectious diseases including COVID-19. Given the consensus on the role of body weight at birth as a practical indicator of the fetal nutritional status during gestation, every subject with a low birth weight should be considered an "at risk" subject for the development of multiple diseases later in life. The hypothesis of the "physiological regenerative medicine," able to improve fetal organs' development in the perinatal period is discussed, in the light of recent experimental data indicating Thymosin Beta-4 as a powerful growth promoter when administered to pregnant mothers before birth.

Kinin B1 receptor controls maternal adiponectin levels and influences offspring weight gain

Given the importance of the kinin B1 receptor in insulin and leptin hormonal regulation, which in turn is crucial in maternal adaptations to ensure nutrient supply to the fetus, we investigated the role of this receptor in maternal metabolism and fetoplacental development. Wild-type and kinin B1 receptor-deficient (B1KO) female mice were mated with male mice of the opposite genotype. Consequently, the entire litter was heterozygous for kinin B1 receptor, ensuring that there would be no influence of offspring genotype on the maternal phenotype. Maternal kinin B1 receptor blockade reduces adiponectin secretion by adipose tissue ex vivo, consistent with lower adiponectin levels in pregnant B1KO mice. Furthermore, fasting insulinemia also increased, which was associated with placental insulin resistance, reduced placental glycogen accumulation, and heavier offspring. Therefore, we propose the combination of chronic hyperinsulinemia and reduced adiponectin secretion in B1KO female mice create a maternal obesogenic environment that results in heavier pups.

Placental insufficiency and heavier placentas in sheep after suppressing CXCL12/CXCR4 signaling during implantation†

During implantation, trophoblast cell invasion and differentiation is predominantly important to achieving proper placental formation and embryonic development. The chemokine, C-X-C motif chemokine ligand 12 (CXCL12) working through its receptor C-X-C motif chemokine receptor 4 (CXCR4) is implicated in implantation and placentation but precise roles of this axis are unclear. Suppressing CXCL12/CXCR4 signaling at the fetal-maternal interface in sheep reduces trophoblast invasion, disrupts uterine remodeling, and diminishes placental vascularization. We hypothesize these negative impacts during implantation will manifest as compromised fetal and placental growth at midgestation. To test, on day 12 postbreeding, osmotic pumps were surgically installed in 30 ewes and delivered intrauterine CXCR4 inhibitor or saline for 7 or 14 days. On day 90, fetal/maternal tissues were collected, measured, weighed, and maternal (caruncle) and fetal (cotyledon) placenta components separated and analyzed. The objectives were to determine if (i) suppressing CXCL12/CXCR4 during implantation results in reduced fetal and placental growth and development and (ii) if varying the amount of time CXCL12/CXCR4 is suppressed impacts fetal/placental development. Fetal weights were similar; however greater placental weight and placentome numbers occurred when CXCL12/CXCR4 was suppressed for 14 days. In caruncles, greater abundance of fibroblast growth factor 2, vascular endothelial growth factor A, vascular endothelial growth factor A receptor 1 (FLT-1), and placental growth factor were observed after suppressing CXCL12/CXCR4. Similar results occurred in cotyledons except less vascular endothelial growth factor in 7 day group and less fibroblast growth factor in 14 day group. Our data underscore the importance of CXCL12/CXCR4 signaling during placentation and provide strong evidence that altering CXCL12-mediated signaling induces enduring placental effects manifesting later in gestation.

Evidence for Wnt signaling's central involvement in perinatal nicotine exposure-induced offspring lung pathology and its modulation by electroacupuncture

OBJECTIVE

Many factors during pregnancy can induce intrauterine growth restriction (IUGR), resulting in various adverse perinatal outcomes such as low birth weight and multiple organ disorders. Among these factors, prenatal smoke/nicotine exposure is a common cause of IUGR, often associated with altered fetal lung development. The classical Wnt signaling pathway plays a vital role in lung development, and its alterations are commonly associated with developmental lung pathologies. The purpose of this study was to determine whether electroacupuncture (EA) at "Zusanli" (ST 36) points protects perinatal nicotine exposure (PNE)-induced offspring lung dysplasia through Wnt/β-catenin signaling pathway and to identify specific Wnt signaling pathway targets of EA.

METHODS

Following a well-established protocol, nicotine (1 mg/kg/ body weight) was administered subcutaneously to pregnant Sprague Dawley rat dams from gestational day 6 to postnatal day 21. In the EA group, dams were treated with EA at both ST 36 acupoints, while in another experimental group, Wnt/β-catenin signaling pathway agonist was injected subcutaneously (2 mg/kg/ body weight). Offspring body weight (PND 1, 7, 14, and 21), lung weight, Wnt signaling markers, pulmonary function, and lung morphology were determined at sacrifice on PND 21. Specifically, Western blotting and Real-time PCR were used to detect the protein and mRNA levels of critical Wnt signaling markers Wnt2, Wnt7b, FZD4, FZD7, LRP5, and LRP6 in the offspring lung. The protein levels of β-catenin in lung tissue of offspring rats were detected by ELISA that of LEF-1 by Western blotting.

RESULTS

Compared to the control group, the body and lung weights of the offspring rats were significantly decreased in the nicotine-only exposed group. The pulmonary function determined as FVC, PEF, TV, and Cdyn was also significantly decreased, while PIF was significantly increased. The protein levels and mRNA expression of Wnt2, Wnt7b, FZD4, FZD7, LRP5, and LRP6 in the lung tissue of the PNE offspring rats were significantly increased. With EA administration at ST 36 acupoints concomitant with nicotine administration, the body and lung weights, pulmonary function (FVC, PEF, PIF, TV, and Cdyn), protein and mRNA levels Wnt signaling pathway markers (Wnt2, Wnt7b, FZD4, FZD7, LRP5, LRP6, β-catenin, and LEF-1) normalized and were not different from the control group. Notably, Wnt agonists agonist administration blocked the protective effects of EA against PNE-induced lung morphological, molecular, and function changes, highlighting the central significance of Wnt pathway signaling in PNE-induced offspring pulmonary pathology and its modulation by EA at ST 36 acupoints.

CONCLUSION

Concomitant maternal EA at ST 36 acupoints from gestational day 6 to PND 21 protects against offspring PNE-induced lung phenotype. The protective effect is achieved by regulating the expression of Wnt ligand proteins (Wnt2 and Wnt7b) and receptor proteins (FZD4, FZD7, LRP5, and LRP6) upstream of the Wnt/β-catenin signaling pathway intermediates β-catenin, and LEF-1.

The association of maternal serum uric acid with the risk of small for gestational age newborn: a retrospective cohort study

PROBLEM

Prior results on the association between serum uric acid (UA) levels in the early trimester and the risk of small for gestational age (SGA) remain unclear. This study evaluated the association of maternal first-, second-, and third-trimester UA levels with the risk of SGA infants.

METHOD OF STUDY

A total of 23, 194 singleton mothers from the International Peace Maternity and Child Health Hospital between January 2014 and January 2017 were included. Maternal UA levels were measured at 12.1 ± 1.08th (UA1) and 32.2 ± 1.03th (UA2) gestational weeks. △UA was calculated as the difference between UA2 and UA1. Logistic regression and restricted cubic spline (RCS) were performed to evaluate the association between maternal UA and △UA during pregnancy and SGA. Receiver operating characteristic (ROC) analysis was employed to assess the serum uric acid prediction value.

RESULTS

Women in the higher quartiles of UA1 had a significantly higher risk of SGA. A clear increased risk for SGA was observed with higher quartiles for UA2 (p for trend <0.05). An approximately "J-shaped" relationship was observed between UA2 and △UA, and the risk of SGA was observed. When compared with those with a lower level of UA in the first trimester, those with a higher level of UA1, the more increase in the later UA levels were associated with a higher risk of SGA [adjusted odds ratio (aOR) = 1.67, 95% CI:1.37-2.05]. The ROC curve areas were 0.525 for UA1, 0.582 for UA2 and 0.576 for △UA.

CONCLUSIONS

The findings suggested that non-preeclamptic and non-hypertensive women who experienced early pregnancy with high UA levels had an elevated risk of SGA. Moreover, a high maternal UA level in the earlier trimester may be an early predictor of SGA.

Metabolic adjustments in neonatal dwarf and normal-sized goat kids: Relationship between serum metabolites and body size

The relationship between body size and metabolism of goats remains poorly studied. The study evaluated the neonatal metabolic adjustments and elucidated the relationship between serum metabolites and body size in 39 single-born dwarf and normal-sized goat kids. Body weight, length and height of kids were recorded at birth and blood samples were collected from the dwarf and normal-sized (Red Sokoto and Sahel) goats on Days 0 (birth), 3, 10 and 20, postnatal. Also, the body mass index (BMI) was calculated and the concentration of metabolic markers was determined. Results revealed that values of BMI, body weight, length and height were lowest (P < 0.01) in the dwarf, followed by values in Red Sokoto kids, while the Sahel kids had the highest (P < 0.01) values. Conversely, the concentration of triglyceride at birth was highest (P < 0.05) in the dwarf, moderate in Red Sokoto and lowest in Sahel goats. Similarly, the Sahel goat kids had the lowest neonatal (P < 0.05) concentration of serum cholesterol. Neonatal concentrations of serum albumin and urea were higher in Sahel than Red Sokoto (P < 0.05) and the dwarf (P > 0.05) goats. Concentration of serum albumin was lower (P < 0.05) at birth, but significantly increased later, while values of serum urea concentration were higher (P < 0.05) at birth, but significantly decreased in subsequent postnatal days. Unlike the BMI, birth weight showed significant negative (P < 0.05) correlation with the concentration of most serum metabolites, especially triglyceride, which showed negative correlation at birth and in subsequent postnatal days. We concluded that dwarfism or small body size is associated with high serum triglyceride in single-born neonatal goats, and this is probably due to the accumulation of body energy reserve in the form of body fat to compensate for lower body tissue mass.

The influence of insulin-related genetic variants on fetal growth, fetal blood flow, and placental weight in a prospective pregnancy cohort

The fetal insulin hypothesis proposes that low birthweight and type 2 diabetes (T2D) in adulthood may be two phenotypes of the same genotype. In this study we aimed to explore this theory further by testing the effects of GWAS-identified genetic variants related to insulin release and sensitivity on fetal growth and blood flow from week 20 of gestation to birth and on placental weight at birth. We calculated genetic risk scores (GRS) of first phase insulin release (FPIR), fasting insulin (FI), combined insulin resistance and dyslipidaemia (IR + DLD) and insulin sensitivity (IS) in a study population of 665 genotyped newborns. Two-dimensional ultrasound measurements with estimation of fetal weight and blood flow were carried out at week 20, 25, and 32 of gestation in all 665 pregnancies. Birthweight and placental weight were registered at birth. Associations between the GRSs and fetal growth, blood flow and placental weight were investigated using linear mixed models. The FPIR GRS was directly associated with fetal growth from week 20 to birth, and both the FI GRS, IR + DLD GRS, and IS GRS were associated with placental weight at birth. Our findings indicate that insulin-related genetic variants might primarily affect fetal growth via the placenta.

Can we influence the neurological development and hair cortisol concentration of offspring by reducing the stress of the mother during pregnancy? A randomized controlled trial

The objective was to evaluate the effects of a stress management cognitive behavioural therapy followed during pregnancy on subsequent childhood on hair cortisol at birth and on neurodevelopment and Hair Cortisol Concentrations (HCC) at 6 months of age. The study sample included 48 pregnant women, divided into two groups: 24 women in the Therapy Group (TG) and 24 women who received standard pregnancy care (control group (CG); CG). To test the therapy efficacy, an evaluation of the HCC and psychological stress, psychopathological symptomatology and resilience was conducted before and after the treatment. The level of cortisol in their hair was obtained during pregnancy and that of their babies at birth. Six months after birth, a cortisol sample was taken from the hair and the babies' neurodevelopment was evaluated based on a Bayley-III test. The TG presented reductions in psychological stress and psychopathological symptomatology after treatment. On the other hand, the CG increased their cortisol concentrations between the pre and post intervention, remaining stable in the TG. Moreover, results showed that TG babies had lower cortisol concentrations at birth and obtained significantly higher cognitive and motor development scores at 6 months. These findings support that providing psychological care to pregnant women may not only have a benefit on these women's mental state, but may also benefit the neurodevelopment of their offspring.

Pregnancy through the Looking-Glass: correlates of disordered eating attitudes among a sample of Lebanese pregnant women

INTRODUCTION

Despite the risks of gestational disordered eating for both the mother and fetus, research into this subject is scarce within developing countries, particularly in Lebanon. Our study's objective was to delve into the predictors of disordered eating attitudes during pregnancy among a sample of Lebanese pregnant women while assessing the potential mediating effect of body dissatisfaction between psychosocial factors and disordered eating attitudes in pregnancy.

METHODS

We framed a cross-sectional study, built on self-report measures. Pregnant women of 18 years old and above were recruited from all the Lebanese governorates through an online survey (N = 433).

RESULTS

The results showed that higher pregnancy-specific hassles (Beta = 0.19), media and pregnant celebrities' influence (Beta = 0.22), and body dissatisfaction (Beta = 0.17) were significantly associated with increased disordered eating attitudes in pregnancy; whereas higher perceived social support (Beta = -0.03), lower socio-economic status (Beta = -0.84), and multigravidity (Beta = -0.96) were significantly associated with less disordered eating attitudes during pregnancy. Body dissatisfaction mediated the association between pregnancy-specific hassles and disordered eating attitudes, and between social appearance concerns and disordered eating attitudes.

CONCLUSION

Our study highlighted that antenatal care, particularly in Lebanon, should no longer be limited to biological monitoring but rather seek to identify possible eating disorders and mental health threats. Further investigations following longitudinal designs should pursue identifying additional correlates of gestational disordered eating in the clinical context, in furtherance of consolidating screening programs and building targeted treatment strategies.

Long-term outcomes for children conceived by assisted reproductive technology

Worldwide, more than 10 million children have been born after assisted reproduction technology (ART), comprising up to 7.9% of children born in Europe and up to 5.1 % of children born in the US in 2018. The short-term outcome for children born after ART is well-known from numerous publications, with higher rates of preterm birth and low birth weight in children born after fresh embryo transfer and higher rates of large for gestational age and high birth weight in children born after frozen embryo transfer compared with children born after spontaneous conception. Higher rates of birth defects in children born after ART have also been shown consistently over time. Studies on long-term health outcomes after ART are scarcer but suggest an increased risk of altered blood pressure and cardiovascular function in children born after ART. In this review, we summarize long-term health outcomes in children born after ART and discuss whether the increased health risks are associated with intrinsic maternal or paternal factors related to subfertility or ART treatments per se. Finally, we speculate where the future will bring us regarding ART treatment strategies and the safety of the mother and child.

Birthweight is associated with clinical characteristics in people with recently diagnosed type 2 diabetes

AIMS/HYPOTHESIS

Low birthweight is a risk factor for type 2 diabetes but it is unknown whether low birthweight is associated with distinct clinical characteristics at disease onset. We examined whether a lower or higher birthweight in type 2 diabetes is associated with clinically relevant characteristics at disease onset.

METHODS

Midwife records were traced for 6866 individuals with type 2 diabetes in the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) cohort. Using a cross-sectional design, we assessed age at diagnosis, anthropomorphic measures, comorbidities, medications, metabolic variables and family history of type 2 diabetes in individuals with the lowest 25% of birthweight (<3000 g) and highest 25% of birthweight (>3700 g), compared with a birthweight of 3000-3700 g as reference, using log-binomial and Poisson regression. Continuous relationships across the entire birthweight spectrum were assessed with linear and restricted cubic spline regression. Weighted polygenic scores (PS) for type 2 diabetes and birthweight were calculated to assess the impact of genetic predispositions.

RESULTS

Each 1000 g decrease in birthweight was associated with a 3.3 year (95% CI 2.9, 3.8) younger age of diabetes onset, 1.5 kg/m2 (95% CI 1.2, 1.7) lower BMI and 3.9 cm (95% CI 3.3, 4.5) smaller waist circumference. Compared with the reference birthweight, a birthweight of <3000 g was associated with more overall comorbidity (prevalence ratio [PR] for Charlson Comorbidity Index Score ≥3 was 1.36 [95% CI 1.07, 1.73]), having a systolic BP ≥155 mmHg (PR 1.26 [95% CI 0.99, 1.59]), lower prevalence of diabetes-associated neurological disease, less likelihood of family history of type 2 diabetes, use of three or more glucose-lowering drugs (PR 1.33 [95% CI 1.06, 1.65]) and use of three or more antihypertensive drugs (PR 1.09 [95% CI 0.99, 1.20]). Clinically defined low birthweight (<2500 g) yielded stronger associations. Most associations between birthweight and clinical characteristics appeared linear, and a higher birthweight was associated with characteristics mirroring lower birthweight in opposite directions. Results were robust to adjustments for PS representing weighted genetic predisposition for type 2 diabetes and birthweight.

CONCLUSION/INTERPRETATION

Despite younger age at diagnosis, and fewer individuals with obesity and family history of type 2 diabetes, a birthweight <3000 g was associated with more comorbidities, including a higher systolic BP, as well as with greater use of glucose-lowering and antihypertensive medications, in individuals with recently diagnosed type 2 diabetes.

Dousing the flame: reviewing the mechanisms of inflammatory programming during stress-induced intrauterine growth restriction and the potential for ω-3 polyunsaturated fatty acid intervention

Intrauterine growth restriction (IUGR) arises when maternal stressors coincide with peak placental development, leading to placental insufficiency. When the expanding nutrient demands of the growing fetus subsequently exceed the capacity of the stunted placenta, fetal hypoxemia and hypoglycemia result. Poor fetal nutrient status stimulates greater release of inflammatory cytokines and catecholamines, which in turn lead to thrifty growth and metabolic programming that benefits fetal survival but is maladaptive after birth. Specifically, some IUGR fetal tissues develop enriched expression of inflammatory cytokine receptors and other signaling cascade components, which increases inflammatory sensitivity even when circulating inflammatory cytokines are no longer elevated after birth. Recent evidence indicates that greater inflammatory tone contributes to deficits in skeletal muscle growth and metabolism that are characteristic of IUGR offspring. These deficits underlie the metabolic dysfunction that markedly increases risk for metabolic diseases in IUGR-born individuals. The same programming mechanisms yield reduced metabolic efficiency, poor body composition, and inferior carcass quality in IUGR-born livestock. The ω-3 polyunsaturated fatty acids (PUFA) are diet-derived nutraceuticals with anti-inflammatory effects that have been used to improve conditions of chronic systemic inflammation, including intrauterine stress. In this review, we highlight the role of sustained systemic inflammation in the development of IUGR pathologies. We then discuss the potential for ω-3 PUFA supplementation to improve inflammation-mediated growth and metabolic deficits in IUGR offspring, along with potential barriers that must be considered when developing a supplementation strategy.

The social formation of fitness: lifetime consequences of prenatal nutrition and postnatal care in a wild mammal population

Research in medicine and evolutionary biology suggests that the sequencing of parental investment has a crucial impact on offspring life history and health. Here, we take advantage of the synchronous birth system of wild banded mongooses to test experimentally the lifetime consequences to offspring of receiving extra investment prenatally versus postnatally. We provided extra food to half of the breeding females in each group during pregnancy, leaving the other half as matched controls. This manipulation resulted in two categories of experimental offspring in synchronously born litters: (i) 'prenatal boost' offspring whose mothers had been fed during pregnancy, and (ii) 'postnatal boost' offspring whose mothers were not fed during pregnancy but who received extra alloparental care in the postnatal period. Prenatal boost offspring lived substantially longer as adults, but postnatal boost offspring had higher lifetime reproductive success (LRS) and higher glucocorticoid levels across the lifespan. Both types of experimental offspring had higher LRS than offspring from unmanipulated litters. We found no difference between the two experimental categories of offspring in adult weight, age at first reproduction, oxidative stress or telomere lengths. These findings are rare experimental evidence that prenatal and postnatal investments have distinct effects in moulding individual life history and fitness in wild mammals. This article is part of the theme issue 'Evolutionary ecology of inequality'.

Neuroprotection in metabolic syndrome by environmental enrichment. A lifespan perspective

Metabolic syndrome (MetS) is defined by the concurrence of different metabolic conditions: obesity, hypertension, dyslipidemia, and hyperglycemia. Its incidence has been increasingly rising over the past decades and has become a global health problem. MetS has deleterious consequences on the central nervous system (CNS) and neurological development. MetS can last several years or be lifelong, affecting the CNS in different ways and treatments can help manage condition, though there is no known cure. The early childhood years are extremely important in neurodevelopment, which extends beyond, encompassing a lifetime. Neuroplastic changes take place all life through - childhood, adolescence, adulthood, and old age - are highly sensitive to environmental input. Environmental factors have an important role in the etiopathogenesis and treatment of MetS, so environmental enrichment (EE) stands as a promising non-invasive therapeutic approach. While the EE paradigm has been designed for animal housing, its principles can be and actually are applied in cognitive, sensory, social, and physical stimulation programs for humans. Here, we briefly review the central milestones in neurodevelopment at each life stage, along with the research studies carried out on how MetS affects neurodevelopment at each life stage and the contributions that EE models can provide to improve health over the lifespan.

Relationship between insulin and Netrin-1/DCC guidance cue pathway regulation in the prefrontal cortex of rodents exposed to prenatal dietary restriction

Fetal restriction (FR) alters insulin sensitivity, but it is unknown how the metabolic profile associated with restriction affects development of the dopamine (DA) system and DA-related behaviors. The Netrin-1/DCC guidance cue system participates in maturation of the mesocorticolimbic DA circuitry. Therefore, our objective was to identify if FR modifies Netrin-1/DCC receptor protein expression in the prefrontal cortex (PFC) at birth and mRNA in adulthood in rodent males. We used cultured HEK293 cells to assess if levels of miR-218, microRNA regulator of DCC, are sensitive to insulin. To assess this, pregnant dams were subjected to a 50% FR diet from gestational day 10 until birth. Medial PFC (mPFC) DCC/Netrin-1 protein expression was measured at P0 at baseline and Dcc/Netrin-1 mRNA levels were quantified in adults 15 min after a saline/insulin injection. miR-218 levels in HEK-293 cells were measured in response to insulin exposure. At P0, Netrin-1 levels are downregulated in FR animals in comparison to controls. In adult rodents, insulin administration results in an increase in Dcc mRNA levels in control but not FR rats. In HEK293 cells, there is a positive correlation between insulin concentration and miR-218 levels. Since miR-218 is a Dcc gene expression regulator and our in vitro results show that insulin regulates miR-218 levels, we suggest that FR-induced changes in insulin sensitivity could be affecting Dcc expression via miR-218, impacting DA system maturation and organization. As fetal adversity is linked to nonadaptive behaviors later in life, this may contribute to early identification of vulnerability to chronic diseases associated with fetal adversity.

Heart function by M-mode and tissue Doppler in the early neonatal period in neonates with fetal growth restriction

BACKGROUND

Fetal growth restricted (FGR) neonates have increased risk of circulatory compromise due to failure of normal transition of circulation after birth.

AIM

Echocardiographic assessment of heart function in FGR neonates first three days after birth.

STUDY DESIGN

Prospective observational study.

SUBJECTS

FGR- and non-FGR neonates.

OUTCOME MEASURES

M-mode excursions and pulsed-wave tissue Doppler velocities normalised for heart size and E/e' of the atrioventricular plane day one, two and three after birth.

RESULTS

Compared with controls (non-FGR of comparable gestational age, n = 41), late-FGR (gestational age ≥ 32 weeks, n = 21) exhibited higher septal excursion (15.9 (0.6) vs. 14.0 (0.4) %, p = 0.021) (mean (SEM)) and left E/e' (17.3 (1.9) vs.11.5 (1.3), p = 0.019). Relative to day three, indexes on day one were higher for left excursion (21 (6) % higher on day one, p = 0.002), right excursion (12 (5) %, p = 0.025), left e' (15 (7) %, p = 0.049), right a' (18 (6) %, p = 0.001), left E/e' (25 (10) %, p = 0.015) and right E/e' (17 (7) %, p = 0.013), whereas no index changed from day two to day three. Late-FGR had no impact on changes from day one and two to day three. No measurements differed between early-FGR (n = 7) and late-FGR.

CONCLUSIONS

FGR impacted neonatal heart function the early transitional days after birth. Late-FGR hearts had increased septal contraction and reduced left diastolic function compared with controls. The dynamic changes in heart function between first three days were most evident in lateral walls, with similar pattern in late-FGR and non-FGR. Early-FGR and late-FGR exhibited similar heart function.

Pathomechanisms of Prenatally Programmed Adult Diseases

Based on epidemiological observations Barker et al. put forward the hypothesis/concept that an adverse intrauterine environment (involving an insufficient nutrient supply, chronic hypoxia, stress, and toxic substances) is an important risk factor for the development of chronic diseases later in life. The fetus responds to the unfavorable environment with adaptive reactions, which ensure survival in the short run, but at the expense of initiating pathological processes leading to adult diseases. In this review, the major mechanisms (including telomere dysfunction, epigenetic modifications, and cardiovascular-renal-endocrine-metabolic reactions) will be outlined, with a particular emphasis on the role of oxidative stress in the fetal origin of adult diseases.

Embryonic vitamin D deficiency programs hematopoietic stem cells to induce type 2 diabetes

Environmental factors may alter the fetal genome to cause metabolic diseases. It is unknown whether embryonic immune cell programming impacts the risk of type 2 diabetes in later life. We demonstrate that transplantation of fetal hematopoietic stem cells (HSCs) made vitamin D deficient in utero induce diabetes in vitamin D-sufficient mice. Vitamin D deficiency epigenetically suppresses Jarid2 expression and activates the Mef2/PGC1a pathway in HSCs, which persists in recipient bone marrow, resulting in adipose macrophage infiltration. These macrophages secrete miR106-5p, which promotes adipose insulin resistance by repressing PIK3 catalytic and regulatory subunits and down-regulating AKT signaling. Vitamin D-deficient monocytes from human cord blood have comparable Jarid2/Mef2/PGC1a expression changes and secrete miR-106b-5p, causing adipocyte insulin resistance. These findings suggest that vitamin D deficiency during development has epigenetic consequences impacting the systemic metabolic milieu.

Birth size, growth trajectory and later cardio-metabolic risk

There is increasing evidence of a strong association between intrauterine growth and subsequent development of chronic disease in adult life. Birth size and growth trajectory have been demonstrated to have an impact on cardio-metabolic health, both in childhood and adult life. Hence, careful observation of the children's growth pattern, starting from the intrauterine period and the first years of life, should be emphasized to detect the possible onset of cardio-metabolic sequelae. This allows to intervene on them as soon as they are detected, first of all through lifestyle interventions, whose efficacy seems to be higher when they are started early. Recent papers suggest that prematurity may constitute an independent risk factor for the development of cardiovascular disease and metabolic syndrome, regardless of birth weight. The purpose of the present review is to examine and summarize the available knowledge about the dynamic association between intrauterine and postnatal growth and cardio-metabolic risk, from childhood to adulthood.

The impact of intrauterine growth restriction and prematurity on nephron endowment

In humans born at term, maximal nephron number is reached by the time nephrogenesis is completed - at approximately 36 weeks' gestation. The number of nephrons does not increase further and subsequently remains stable until loss occurs through ageing or disease. Nephron endowment is key to the functional capacity of the kidney and its resilience to disease; hence, any processes that impair kidney development in the developing fetus can have lifelong adverse consequences for renal health and, consequently, for quality and length of life. The timing of nephrogenesis underlies the vulnerability of developing human kidneys to adverse early life exposures. Indeed, exposure of the developing fetus to a suboptimal intrauterine environment during gestation - resulting in intrauterine growth restriction (IUGR) - and/or preterm birth can impede kidney development and lead to reduced nephron endowment. Furthermore, emerging research suggests that IUGR and/or preterm birth is associated with an elevated risk of chronic kidney disease in later life. The available data highlight the important role of early life development in the aetiology of kidney disease and emphasize the need to develop strategies to optimize nephron endowment in IUGR and preterm infants.

Birth weight and cardiometabolic risk factors: a discordant twin study in the UK Biobank

One of the longstanding debates in life-course epidemiology is whether an adverse intrauterine environment, often proxied by birth weight, causally increases the future risk of cardiometabolic disease. The use of a discordant twin study design, which controls for the influence of shared genetic and environmental confounding factors, may be useful to investigate whether this relationship is causal. We conducted a discordant twin study of 120 monozygotic (MZ) and 148 dizygotic (DZ) twin pairs from the UK Biobank to explore the potential causal relationships between birth weight and a broad spectrum of later-life cardiometabolic risk factors. We used a linear mixed model to investigate the association between birth weight and later-life cardiometabolic risk factors for twins, allowing for both within-pair differences and between-pair differences in birth weight. Of primary interest is the within-pair association between differences in birth weight and cardiometabolic risk factors, which could reflect an intrauterine effect on later-life risk factors. We found no strong evidence of association in MZ twins between the within-pair differences in birth weight and most cardiometabolic risk factors in later life, except for nominal associations with C-reactive protein and insulin-like growth factor 1. However, these associations were not replicated in DZ twin pairs. Our study provided no strong evidence for intrauterine effects on later-life cardiometabolic risk factors, which is consistent with previous large-scale studies of singletons testing the potential causal relationship. It does not support the hypothesis that adverse intrauterine environments increase the risk of cardiometabolic disease in later life.