Neonatal leptin administration alters regional brain volumes and blocks neonatal growth restriction-induced behavioral and cardiovascular dysfunction in male mice.

Premature delivery is often complicated by neonatal growth restriction (GR) and neurodevelopmental impairment. Because global overnutrition increases the risk of adult metabolic syndrome, we sought a targeted intervention. Premature delivery and perinatal GR decrease circulating levels of the neurotrophic hormone leptin. We hypothesized that leptin supplementation would normalize the outcomes of mice with incipient neonatal GR. Pups were fostered into litters of 6 or 12 to elicit divergent growth patterns. Pups in each litter received injections of saline or leptin from d 4 to 14. At 4 mo, mice underwent tail cuff blood pressure measurement, behavioral testing, and MRI. Mice fostered in litters of 12 had decreased weanling weights and leptin levels. Neonatal leptin administration normalized plasma leptin levels without influencing neonatal growth. Leptin replacement also normalized the hypertension, stress-linked immobility, conditioned fear, and amygdala enlargement seen in neonatal growth restricted male mice. In control males, neonatal leptin administration led to hypothalamic enlargement, without overt neurocardiovascular alterations. Female mice were less susceptible to the effects of neonatal GR or leptin supplementation. In conclusion, the effects of neonatal leptin administration are modulated by concurrent growth and gender. In growth restricted male mice, physiologic leptin replacement improves adult neurocardiovascular outcomes.

Neonatal catch up growth increases diabetes susceptibility but improves behavioral and cardiovascular outcomes of low birth weight male mice.

Premature infants are at increased risk for persistent growth failure, neurodevelopmental impairment, hypertension, and diabetes. Rapid neonatal growth has been linked to the increasing prevalence of diabetes and obesity. Nutritional goals for the premature infant with incipient growth failure have thus become a source of controversy. We used isogenic mice with natural variation in perinatal growth to test the hypothesis that neonatal catch up growth improves the neurobehavioral and cardiovascular outcomes of low-birth weight mice, despite an increase in diabetes susceptibility. Adult mice that experienced prenatal and neonatal growth restriction had persistent growth failure, hypertension, and neurobehavioral alterations. When switched from standard rodent chow to a hypercaloric diet, growth restricted mice were protected from diet-induced obesity. Among low-birth weight male mice, neonatal catch up growth normalized neurobehavioral and cardiovascular phenotypes, but led to insulin resistance and high fat diet-induced diabetes. Among low-birth weight female mice, neonatal catch up growth did not prevent the development of adult hypertension and significantly increased measures of anxiety, including self-injury and the avoidance of open spaces. These studies support the importance of the perinatal environment in the resetting of adult disease susceptibility and suggest an earlier window of vulnerability among growth restricted female mice.