Associations of cord blood leptin and adiponectin with children's cognitive abilities

Molecular pathways in placental-fetal development and disruption

The first trimester of pregnancy ranks high in priority when minimizing harmful exposures, given the wide-ranging types of organogenesis occurring between 4- and 12-weeks' gestation. One way to quantify potential harm to the fetus in the first trimester is to measure a corollary effect on the placenta. Placental biomarkers are widely present in maternal circulation, cord blood, and placental tissue biopsied at birth or at the time of pregnancy termination. Here we evaluate ten diverse pathways involving molecules expressed in the first trimester human placenta based on their relevance to normal fetal development and to the hypothesis of placental-fetal endocrine disruption (perturbation in development that results in abnormal endocrine function in the offspring), namely: human chorionic gonadotropin (hCG), thyroid hormone regulation, peroxisome proliferator activated receptor protein gamma (PPARγ), leptin, transforming growth factor beta, epiregulin, growth differentiation factor 15, small nucleolar RNAs, serotonin, and vitamin D. Some of these are well-established as biomarkers of placental-fetal endocrine disruption, while others are not well studied and were selected based on discovery analyses of the placental transcriptome. A literature search on these biomarkers summarizes evidence of placenta-specific production and regulation of each biomarker, and their role in fetal reproductive tract, brain, and other specific domains of fetal development. In this review, we extend the theory of fetal programming to placental-fetal programming.

Maternal metabolic syndrome in pregnancy and child development at age 5: exploring mediating mechanisms using cord blood markers

BACKGROUND

There is limited evidence on how the classification of maternal metabolic syndrome during pregnancy affects children's developmental outcomes and the possible mediators of this association. This study uses a cohort sample of 12,644 to 13,832 mother-child pairs from the UK Born in Bradford Study to examine the associations between maternal metabolic syndrome classification (MetS) and child development outcomes at age 5, using cord blood markers as candidate mediators.

METHODS

Maternal cardiometabolic markers included diabetes, obesity, triglycerides, high-density lipoprotein cholesterol, blood pressure, hypertension, and fasting glucose during pregnancy. Cord blood markers of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, leptin, and adiponectin were used as child mediators. Child outcomes included two starting school variables: British Picture Vocabulary Scale (BPVS) and the Letter Identification Assessment (LID), and five developmental milestone domains from a national UK framework: (1) communication and language (COM); (2) personal, social, and emotional (PSE); (3) physical development (PHY); (4) literacy (LIT); and (5) mathematics (MAT). Mediation models were used to examine the associations between the classification of maternal metabolic syndrome and child developmental milestones. Models were adjusted for potential maternal, socioeconomic, and child confounders such as maternal education, deprivation, and gestational age.

RESULTS

In mediation models, significant total effects were found for MetS associations with children's development in the LIT domain at age 5. MetS predicted individual cord blood mediators of lower HDL and increased leptin levels in both adjusted and unadjusted models. Total indirect effects (effects of all mediators combined) for MetS on a child's COM and PSE domain were significant, through all child cord blood mediators of LDL, HDL, triglycerides, adiponectin, and leptin for adjusted models.

CONCLUSIONS

The results support the hypothesis that maternal metabolic syndrome classification during pregnancy is associated with some child developmental outcomes at age 5. After adjusting for maternal, child, and environmental covariates, maternal metabolic syndrome classification during pregnancy was associated with children's LIT domain through direct effects of maternal metabolic health and indirect effects of cord blood markers (total effects), and COM and PSE domains via changes only in a child's cord blood markers (total indirect effects).

Prediction of cord blood leptin on infant's neurodevelopment: A birth cohort in rural Yunnan, China

BACKGROUND

Leptin, one of the peptide hormones secreted by adipocytes, plays a vital part in metabolism, but its role in early-life neurodevelopment remains poorly understood.

METHODS

We performed leptin analysis on 323 cord blood samples collected from a birth cohort in Yunnan rural area, China, and assessed infants' neurodevelopment at one year of age by the Bayley Scales of Infant and Toddler Development-Third Edition (BSID-III). Multiple linear regression and binary logistic regression models were used to explore the associations between cord blood leptin (CBL) concentrations and infants' neurodevelopment and the ability of CBL to predict the probabilities of infants' neurodevelopment delay.

RESULTS

Overall, 323 infants were included in this study. The median concentration of CBL was 4.7 ng/ml. The proportion of 1-year-old infants identified as being neurodevelopmental delayed was 34.5%, and delays in cognitive, language, and motor domains were 11.1%, 26.6%, and 13.9%, respectively. Multiple linear regression analyses manifested that the CBL concentration (log10-transformed) was positively correlated with the cognitive, language, and motor composite scores in infants, respectively (β = 7.76, 95%CI: 3.81-11.71; β = 6.73, 95%CI: 3.41-10.06; and β = 6.88, 95%CI: 3.48-10.29, respectively). Binary logistic regression analysis showed that compared with the higher, lower CBL (< 4.7 ng/ml) yielded a 1.41-fold increase in the risk of language development delay (OR = 2.41，95%CI: 1.42-4.09), a 1.49-fold higher risk of motor development delay (OR = 2.49, 95%CI: 1.25-4.96), and a 1.71-fold higher risk of neurodevelopment delay (OR = 2.71, 95%CI: 1.64-4.48) among infants. The prediction models showed that the probabilities of development delay in infants' language, motor, and neurodevelopment increased with the decline of CBL concentrations [r_s = -0.63 (95% CI: -0.71, -0.56), r_s = -0.46 (95% CI: -0.55, -0.38), r_s = -0.55 (95% CI: -0.63, -0.46), respectively].

CONCLUSION

The decline of CBL was associated with the decrease in infants' neurodevelopment scores at one year of age. CBL below 4.7 ng/ml may increase the risk of infants' neurodevelopment delay. The probabilities of infants' neurodevelopment delay increased with the decrease of CBL concentrations. CBL may be a predictor of the probability of children's neurodevelopment delay.

Using Latent Profile Analysis to Identify Associations Between Gestational Chemical Mixtures and Child Neurodevelopment

BACKGROUND

Unsupervised machine learning techniques have become increasingly popular for studying associations between gestational exposure mixtures and human health. Latent profile analysis is one method that has not been fully explored.

METHODS

We estimated associations between gestational chemical mixtures and child neurodevelopment using latent profile analysis. Using data from the Maternal-Infant Research on Environmental Chemicals (MIREC) research platform, a longitudinal cohort of pregnant Canadian women and their children, we generated latent profiles from 27 gestational exposure biomarkers. We then examined the associations between these profiles and child Verbal IQ, Performance IQ, and Full-Scale IQ, measured with the Wechsler Preschool and Primary Scale of Intelligence, Third Edition (WPPSI-III). We validated our findings using k-means clustering.

RESULTS

Latent profile analysis detected five latent profiles of exposure: a reference profile containing 61% of the study participants, a high monoethyl phthalate (MEP) profile with moderately low persistent organic pollutants (POPs) containing 26%, a high POP profile containing 6%, a low POP profile containing 4%, and a smoking chemicals profile containing 3%. We observed negative associations between both the smoking chemicals and high MEP profiles and all IQ scores and between the high POP profile and Full-Scale and Verbal IQ scores. We also found a positive association between the low POP profile and Full-Scale and Performance IQ scores. All associations had wide 95% confidence intervals.

CONCLUSIONS

Latent profile analysis is a promising technique for identifying patterns of chemical exposure and is worthy of further study for its use in examining complicated exposure mixtures.

Paternal dietary ratio of n-6: n-3 polyunsaturated fatty acids programs offspring leptin expression and gene imprinting in mice

Background

This study determined the effects of the paternal dietary ratio of n-6: n-3 polyunsaturated fatty acids (PUFAs) on leptin expression in the offspring and associated gene imprinting in a mouse model.

Methods

Three- to four-week-old male C57BL/6J mice (F0) were fed an n-3 PUFA-deficient (n-3 D) diet, a diet with normal n-3 PUFA content (n-3 N; n-6: n-3 = 4.3:1), or a diet with a high n-3 PUFA content (n-3 H; n-6: n-3 = 1.5:1) for 8 weeks. Two subsequent generations were generated by mating F0 and F1 male mice with 10-week-old virgin female C57 BL/6J mice, to produce F1 and F2 offspring.

Results

Compared to the paternal n-3 D diet, paternal n-3 N and n-3 H diets reduced adipose mRNA expression of leptin (Lep) and its plasma concentrations in juvenile F1 male and female offspring, and adult F1 male and F2 female offspring, with upregulated Lep receptor mRNA expression in the hypothalamus. Meanwhile, paternal n-3 N and n-3 H diets altered the expression of the imprinted genes H19, Igf2, Igf2r, Plagl1, Cdkn1c, Kcnq1ot1, Peg3, and Grb10 in the adipose tissue of juvenile and adult F1 males, with almost no effects on F1 females, while more effects were observed in the adult F2 females than F2 males. Principal component analysis verified that Plagl1, Cdkn1c, and Kcnq1ot1 contributed the most to variation in adipose tissue expression in all offspring. Some of these genes (Plagl1, Cdkn1c, Kcnq1ot1, Peg3, and Grb10) were altered by the paternal n-3 N and n-3 H diets in the F1 and F2 generation testes as well. Furthermore, adipose Lep expression was positively correlated with expressions of H19, Igf2r, Plagl1, and Kcnq1ot1 in juvenile F1 males and females, negatively correlated with the Kcnq1ot1 expression in adult F1 males, and positively correlated with the Plagl1 expression in adult F2 females.

Conclusion

These data imply that paternal Plagl1, Cdkn1c, and Kcnq1ot1 might be part of the pathways involved in offspring leptin programming. Therefore, a lower ratio of n-6: n-3 PUFAs, with higher intake of n-3 PUFAs in paternal pre-conception, may help maintain the offspring's optimal leptin pattern in a sex-specific manner through multiple generations, and thereby, be beneficial for the offspring's long-term health.

The impact of maternal high-fat diet on offspring neurodevelopment

A maternal high-fat diet affects offspring neurodevelopment with long-term consequences on their brain health and behavior. During the past three decades, obesity has rapidly increased in the whole human population worldwide, including women of reproductive age. It is known that maternal obesity caused by a high-fat diet may lead to neurodevelopmental disorders in their offspring, such as autism spectrum disorder, attention deficit hyperactivity disorder, anxiety, depression, and schizophrenia. A maternal high-fat diet can affect offspring neurodevelopment due to inflammatory activation of the maternal gut, adipose tissue, and placenta, mirrored by increased levels of pro-inflammatory cytokines in both maternal and fetal circulation. Furthermore, a maternal high fat diet causes gut microbial dysbiosis further contributing to increased inflammatory milieu during pregnancy and lactation, thus disturbing both prenatal and postnatal neurodevelopment of the offspring. In addition, global molecular and cellular changes in the offspring's brain may occur due to epigenetic modifications including the downregulation of brain-derived neurotrophic factor (BDNF) expression and the activation of the endocannabinoid system. These neurodevelopmental aberrations are reflected in behavioral deficits observed in animals, corresponding to behavioral phenotypes of certain neurodevelopmental disorders in humans. Here we reviewed recent findings from rodent models and from human studies to reveal potential mechanisms by which a maternal high-fat diet interferes with the neurodevelopment of the offspring.

Metabolic proteins at birth predict early childhood mental health symptoms

Child mental health disorders are the leading cause of disability in children and adolescents worldwide. Biological correlates predict psychosocial outcomes throughout human development; however, less is known about metabolic proteins. Drawing from a longitudinal birth cohort study, Born in Bradford (BiB), we examined the role of infant metabolic proteins at birth in predicting early childhood mental health symptoms at 3 and 5 years. We found that higher leptin predicted more prosocial behavior at age 3. Additionally, a higher leptin-to-adiponectin ratio predicted increased total symptom difficulties. At age 5, we found that higher adiponectin predicted a decreased likelihood of being rated by teachers as meeting or exceeding expectations in the domain of "managing feelings and behaviors" and marginally predicted lower competency in "making relationships" on national developmental milestone evaluations. To our knowledge, this is among the first few studies to prospectively predict mental health symptoms from cord blood metabolic proteins, and the first examining this association with a leptin-to-adiponectin ratio. Our results provide support for the possibility that metabolic proteins at birth forecast risk for mental health symptoms in early childhood.

Plasma leptin, but not adiponectin, is associated with cognitive impairment in older adults

BACKGROUND

Leptin and adiponectin are adipose-tissue derived hormones primarily involved in glucose, lipid, and energy metabolism, inflammation, and atherosclerosis. Both adipokines may cross the blood-brain barrier but evidence on their roles in cognitive impairment is limited and conflicting. Here, we determined associations of plasma adipokine concentration with cognitive impairment in older adults.

METHODS

Cross-sectional analysis of baseline data from 669 participants aged ≥65 years of the Biomarker Development for Postoperative Cognitive Impairment in the Elderly (BioCog) study were recruited 2014-2017 at study sites in Berlin, Germany and Utrecht, the Netherlands. Cognitive impairment was defined as the lowest tertile of a cognitive summary score derived from six neuropsychological tests.

RESULTS

After adjustment for age, sex, fasting, BMI, diabetes, hypertension, cerebrovascular disease, and coronary heart disease, higher leptin concentrations and a higher leptin/adiponectin ratio (LAR) were associated with a higher odds of cognitive impairment (OR per 1 SD higher leptin concentration, 1.33; 95 % CI 1.05, 1.69; p = 0.02; OR per 1 SD higher LAR, 1.26; 95 % CI 1.01, 1.57; p = 0.04). Sensitivity analyses determined that these findings were driven by the non-obese group (BMI < 30 kg/m²), whereas leptin and LAR were not associated with cognitive impairment in the obese group (BMI ≥ 30 kg/m²). Soluble leptin receptor, leptin/soluble leptin receptor ratio, total adiponectin and high-molecular weight adiponectin concentrations were each not associated with impairment.

CONCLUSIONS

With leptin as a known promoter of atherosclerosis and inflammation, our findings point to a pathogenic role of leptin in age-related cognitive impairment that may be limited to non-obese individuals and warrants further investigation.

Adolescent follow-up in the Health Outcomes and Measures of the Environment (HOME) Study: cohort profile

PURPOSE

Environmental chemical exposures may adversely affect an array of adolescent health outcomes. Thus, we used the Health Outcomes and Measures of the Environment (HOME) study, a prospective cohort that recruited pregnant women and conducted longitudinal follow-up on children over the first 12 years of life, to determine if and when chemical exposures affect adolescent health.

PARTICIPANTS

We recruited 468 pregnant women (age range: 18-45 years) from the Cincinnati, Ohio region to participate in a cohort study between March 2003 and January 2006. Follow-up included two clinic and one home visits during pregnancy, a delivery hospital visit, and four home and six clinic visits when children were aged 4 weeks and 1, 2, 3, 4, 5 and 8 years. Of 441 children available for follow-up, 396 (90%) completed at least one follow-up and 256 (58%) completed the most recent follow-up at 12 years of age (range: 11-14).

FINDINGS TO DATE

Our new measures include maternal/child report of internalising symptoms, neuroimaging, dual-energy X-ray absorptiometry-derived estimates of lean/adipose tissue and bone mineral density, and cardiometabolic risk biomarkers. We assessed adolescent exposure to perfluoroalkyl substances, phenols, phthalates and flame retardants. Participants completing follow-up at 12 years of age were similar to the original cohort in terms of baseline factors. Most children had typical and expected values for this age on measures of internalising symptoms, body composition, bone density and cardiometabolic risk markers. Notably, 36% and 11% of children had scores indicative of potential anxiety and depressive disorders, respectively. Approximately 35% of children were overweight or obese, with higher prevalence among girls. Thirty-three per cent of children had borderline or high triglyceride concentrations (>90 mg/dL).

FUTURE PLANS

We will examine associations of early life environmental chemical exposures with adolescent health measures while considering potential periods of heightened susceptibility and mixture effects.

TRIAL REGISTRATION NUMBER

NCT00129324.

Human milk oligosaccharide 2'-fucosyllactose links feedings at 1 month to cognitive development at 24 months in infants of normal and overweight mothers

BACKGROUND

Infant cognitive development is influenced by maternal factors that range from obesity to early feeding and breast milk composition. Animal studies suggest a role for human milk oligosaccharide (HMO), 2'-fucosyllactose (2'FL), on learning and memory, yet no human studies have examined its impact on infant cognitive development relative to other HMOs and maternal factors.

OBJECTIVE

To determine the impact of 2'FL from breast milk feeding on infant cognitive development at 24 months of age relative to maternal obesity and breast milk feeding frequency.

METHODS AND MATERIALS

Hispanic mother-infant pairs (N = 50) were recruited across the spectrum of pre-pregnancy BMI. Breast milk was collected at 1 and 6 months, and feedings/day were reported. Nineteen HMOs were analyzed using high-performance liquid chromatography, with initial interest in 2'FL. Infant cognitive development score was assessed with the Bayley-III Scale at 24 months. Linear regressions were used for prediction, and bootstrapping to determine mediation by 2'FL.

RESULTS

Maternal pre-pregnancy BMI was not related to feedings/day or HMOs, but predicted poorer infant cognitive development (β = -0.31, P = 0.03). Feedings/day (β = 0.34) and 2'FL (β = 0.59) at 1 month predicted better infant cognitive development (both P≤ 0.01). The association of feedings/day with infant cognitive development was no longer significant after further adjustment for 2'FL (estimated mediation effect = 0.13, P = 0.04). There were no associations of feedings/day and 2'FL at 6 months with infant cognitive development.

CONCLUSIONS

Our findings suggest that maternal factors influence infant cognitive development through multiple means. Though maternal obesity may be a separate negative influence, greater frequency of breast milk feeding at 1 month contributed to infant cognitive development through greater exposure to 2'FL relative to other HMOs. The influence of 2'FL was not significant at 6 months, indicating that early exposure to 2'FL may be a critical temporal window for positively influencing infant cognitive development.