Brown adipose tissue genes in pericardial adipose tissue of newborn sheep are downregulated by maternal nutrient restriction in late gestation.

BACKGROUND

Brown adipose tissue (BAT) thermogenesis is essential for newborn survival. Pericardial adipose tissue is a visceral depot that promotes metabolic and cardiovascular adaptations. We determined whether BAT is present in pericardial adipose tissue in newborns and whether maternal nutrition during late gestation compromises BAT in the postnatal period.

METHODS

We measured uncoupling protein 1 (UCP1) and other BAT-specific genes (e.g., β3-adrenergic receptor (β3ADR) and deiodinase type 2 (DIO2)), together with markers of white adipose tissue (WAT) in sheep on either the first or 30th day after birth. These were twin offspring born to mothers fed with either 100% or nutrient restricted (NR) to 60% of their total metabolizable requirements from 110 d gestation to term.

RESULTS

Gene expression of UCP1 and other BAT-related genes decreased significantly with age. In newborns, maternal nutrient restriction downregulated gene expression of DIO2 and the β3-adrenergic receptor with reduced UCP1 but had no effect on genes predominantly expressed in WAT.

CONCLUSION

BAT is present around the heart in newborns. Exposure to a suboptimal maternal diet in late gestation specifically compromises BAT development and has the potential to place these offspring at increased risk of hypothermia after birth without effects on the subsequent appearance of WAT.