Developmental programming of energy balance regulation: is physical activity more 'programmable' than food intake?
Extensive human and animal model data show that environmental influences during critical periods of prenatal and early postnatal development can cause persistent alterations in energy balance regulation. Although a potentially important factor in the worldwide obesity epidemic, the fundamental mechanisms underlying such developmental programming of energy balance are poorly understood, limiting our ability to intervene. Most studies of developmental programming of energy balance have focused on persistent alterations in the regulation of energy intake; energy expenditure has been relatively underemphasised. In particular, very few studies have evaluated developmental programming of physical activity. The aim of this review is to summarise recent evidence that early environment may have a profound impact on establishment of individual propensity for physical activity. Recently, we characterised two different mouse models of developmental programming of obesity; one models fetal growth restriction followed by catch-up growth, and the other models early postnatal overnutrition. In both studies, we observed alterations in body-weight regulation that persisted to adulthood, but no group differences in food intake. Rather, in both cases, programming of energy balance appeared to be due to persistent alterations in energy expenditure and spontaneous physical activity (SPA). These effects were stronger in female offspring. We are currently exploring the hypothesis that developmental programming of SPA occurs via induced sex-specific alterations in epigenetic regulation in the hypothalamus and other regions of the central nervous system. We will summarise the current progress towards testing this hypothesis. Early environmental influences on establishment of physical activity are likely an important factor in developmental programming of energy balance. Understanding the fundamental underlying mechanisms in appropriate animal models will help determine whether early life interventions may be a practical approach to promote physical activity in man.
Department of Pediatrics,Baylor College of Medicine,USDA/ARS Children's Nutrition Research Center,Houston, TX,USA.
Shaoyu
S
Zhu
Department of Pediatrics,Baylor College of Medicine,USDA/ARS Children's Nutrition Research Center,Houston, TX,USA.
Jesse
J
Eclarinal
Department of Pediatrics,Baylor College of Medicine,USDA/ARS Children's Nutrition Research Center,Houston, TX,USA.
Maria S
MS
Baker
Department of Biochemistry,Weill Cornell Medical College of Cornell University,New York,NY,USA.
Ge
G
Li
Department of Pediatrics,Baylor College of Medicine,USDA/ARS Children's Nutrition Research Center,Houston, TX,USA.
Robert A
RA
Waterland
 SL small litters;  SPA spontaneous physical activity; DNA methylation; Epigenetics; Metabolic imprinting; Nutrition