Placental Leptin a Possible New Growth Factor in Intrauterine and Newborn Development

Pediatric researchers from the duPont Hospital for Children, the close affiliate of Thomas Jefferson University, have identified the presence of leptin, a protein linked with obesity, in placental tissues and cells and at elevated levels in the blood of newborns, suggesting that leptin aids in intrauterine and neonatal growth and development. These findings appear in the July issue of Pediatrics.

The study, led by Sandra Hassink, MD, Director of the Weight Management Program at duPont and Clinical Instructor of Pediatrics at Jefferson Medical College, builds upon previous studies conducted at Jefferson. Dr. Hassink and her research team extended this research which explained how the human counterpart of the mouse obesity gene, or ob gene, can be cloned and sequenced to investigate the body's system of energy regulation. These earlier studies also showed that increased blood leptin concentrations correlated with obesity in children and adults.

"Using the previous research as a guide, our team hypothesized that since leptin is directly linked to the storing of fat in children and adults, it may play a vital role in the dynamic energy needs for growth and development in the fetus and neonate," explained Dr. Hassink.

The researchers enrolled 100 mother/newborn pairs in the study, taking blood samples from the mothers and cord blood specimens from the newborns immediately after birth. The team obtained placental tissue from five mothers and studied two human placental cell lines.

"The newborns had higher leptin concentrations than those common among children at puberty, who typically have elevated levels that precede their rapid growth. Further, we found 13 percent of the newborns had higher leptin concentrations than their mothers," said Dr. Hassink. "Leptin was also present in large amounts in each placenta and cell line studied."

These findings suggest that leptin has a role in intrauterine and neonatal development and that the placenta provides a source of leptin for the growing fetus. "To my knowledge, ours is the first study that suggests that the placenta is a significant source of leptin, providing a new twist to leptin and obesity research," said Dr. Hassink.

"This study highlights the importance of pediatrics in this area of research, broadening the understanding of the functions leptin plays during each stage of life."

Alan R. Spitzer, MD, Chairman of Pediatrics at duPont and Jefferson and a member of the research team, echoes Dr. Hassink's thoughts on the significance of the study findings adding, "Discovering that leptin may play an important part in placental function has the potential for a greater understanding of fetal growth and development giving us the opportunity to better assess and ultimately improve birth outcomes."

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