Fetal programming of adipose tissue function: an evolutionary perspective

Role of Hormones During Gestation and Early Development: Pathways Involved in Developmental Programming

Accumulating evidence suggests that an altered maternal milieu and environmental insults during the intrauterine and perinatal periods of life affect the developing organism, leading to detrimental long-term outcomes and often to adult pathologies through programming effects. Hormones, together with growth factors, play critical roles in the regulation of maternal-fetal and maternal-neonate interfaces, and alterations in any of them may lead to programming effects on the developing organism. In this chapter, we will review the role of sex steroids, thyroid hormones, and insulin-like growth factors, as crucial factors involved in physiological processes during pregnancy and lactation, and their role in developmental programming effects during fetal and early neonatal life. Also, we will consider epidemiological evidence and data from animal models of altered maternal hormonal environments and focus on the role of different tissues in the establishment of maternal and fetus/infant interaction. Finally, we will identify unresolved questions and discuss potential future research directions.

Associations Between Maternal Lipid Blood Levels at the 13th Week of Pregnancy and Offspring's Adiposity at Age 11-12 Years

CONTEXT

There is increasing evidence that intrauterine lipid metabolism influences the adiposity of the newborn and the first years thereafter. It remains unclear if these effects persist when these children grow older.

OBJECTIVE

This study examined the associations between maternal lipid blood levels during the 13th week of pregnancy and an offspring's adiposity, measured at age 11-12, and if these associations were moderated by the child's sex.

METHODS

Data were obtained from a community-based birth cohort, the Amsterdam Born Children and their Development (ABCD) study. At a median of 13 weeks' gestation, nonfasting blood samples of triglycerides (TGs), total cholesterol (TC), free fatty acids (FFAs), and apolipoprotein B/apolipoprotein A1 ratio (ApoB/ApoA1) were measured. An offspring's body mass index (BMI), subcutaneous fat (SCF), waist-to-height-ratio (WHtR), and fat percentage (fat%) were measured at age 11-12. Mothers with at-term born children were included (n = 1853). Multivariable linear regression analyses were performed to assess the associations between maternal lipids and each offspring's adiposity outcome separately. Sex differences were additionally evaluated.

RESULTS

TGs, TC, ApoB/ApoA1, and FFAs were significantly positively associated with BMI, WHtR, and fat% (adjusted for gestational age at blood sampling, child's age, sex, and sexual maturation). After additional adjustments for potential confounders and covariates, only TGs remained significantly associated with WHtR (0.45, 95% CI -0.007; 0.91). There were no associations between maternal lipids and SCF and no clear sex-specific results were found.

CONCLUSION

Overall, our results do not strongly support that maternal lipid profile during the 13th week of pregnancy has programming effects on adiposity in preadolescence.

The good and the BAT of metabolic sex differences in thermogenic human adipose tissue

Thermogenic adipose tissue, which comprises classical brown and beige adipose tissue, has the ability to improve systemic metabolism. Its identification in adult humans has fostered extensive investigations on the therapeutic value to counteract obesity and metabolic disorders. Sex and gender differences of human thermogenic adipose tissue, however, are still understudied despite their importance for personalized treatment options. Here, we review studies reporting human sex differences of thermogenic adipose tissue and related potential improvements of systemic energy metabolism. An increasing body of evidence suggests higher prevalence, mass and activity of thermogenic adipose tissue in women, but the consequences for metabolic disease progression and mechanisms are largely unknown. Therefore, we also discuss observations on sex-specific adipose metabolism in experimental mouse and rat studies that may assist to establish molecular mechanisms and instruct future investigations in humans.

Supplementation of polar lipids-enriched milk fat globule membrane in high-fat diet-fed rats during pregnancy and lactation promotes brown/beige adipocyte development and prevents obesity in male offspring

Promoting brown adipose tissue (BAT) function or browning of white adipose tissue (WAT) provides a defense against obesity. The aim of the study was to investigate whether maternal polar lipids-enriched milk fat globule membrane (MFGM-PL) supplementation to high-fat diet (HFD) rats during pregnancy and lactation could promote brown/beige adipogenesis and protect against HFD-induced adiposity in offspring. Female SD rats were fed a HFD for 8 weeks to induce obesity and, then, fed a HFD during pregnancy and lactation with or without MFGM-PL. Male offspring were weaned at postnatal Day 21 and then fed a HFD for 9 weeks. MFGM-PL treatment to HFD dams decreased the body weight gain and WAT mass as well as lowered the serum levels of insulin and triglycerides in male offspring at weaning. MFGM-PL+HFD offspring showed promoted thermogenic function in BAT and inguinal WAT through the upregulation of UCP1 and other thermogenic genes. In adulthood, maternal MFGM-PL supplementation reduced adiposity and increased oxygen consumption, respiratory exchange ratio, and heat production in male offspring. The enhancement of energy expenditure was correlated with elevated BAT activity and inguinal WAT thermogenic program. In conclusion, maternal MFGM-PL treatment activated thermogenesis in offspring, which exerted long-term beneficial effects against HFD-induced obesity in later life.

Maternal n-3 PUFA supplementation promotes fetal brown adipose tissue development through epigenetic modifications in C57BL/6 mice

Brown adipose tissue (BAT) is a crucial regulator of energy expenditure. Emerging evidence suggests that n-3 PUFA potentiate brown adipogenesis in vitro. Since the pregnancy and lactation is a critical time for brown fat formation, we hypothesized that maternal supplementation of n-3 PUFA promotes BAT development in offspring. Female C57BL/6 mice were fed a diet containing n-3 PUFA (3%) derived from fish oil (FO), or an isocaloric diet devoid of n-3 PUFA (Cont) during pregnancy and lactation. Maternal n-3 PUFA intake was delivered to the BAT of neonates significantly reducing the n-6/n-3 ratio. The maternal n-3 PUFA exposure was linked with upregulated brown-specific gene and protein profiles and the functional cluster of brown-specific miRNAs. In addition, maternal n-3 PUFA induced histone modifications in the BAT evidenced by 1) increased epigenetic signature of brown adipogenesis, i.e., H3K27Ac and H3K9me2, 2) modified chromatin-remodeling enzymes, and 3) enriched the H3K27Ac in the promoter region of Ucp1. The offspring received maternal n-3 PUFA nutrition exhibited a significant increase in whole-body energy expenditure and better maintenance of core body temperature against acute cold treatment. Collectively, our results suggest that maternal n-3 PUFA supplementation potentiates fetal BAT development via the synergistic action of miRNA production and histone modifications, which may confer long-lasting metabolic benefits to offspring.