Thursday, November 18, 2010

Diapers yield developmental data

By Robin Tricoles

With the help of babies and more than 5,000 of their diapers, Emory researchers have developed an accurate, noninvasive way to determine estrogen levels in infants. The method, described in the journal Frontiers in Systems Biology, will allow comparisons of estrogen levels in human infants and their long-term reproductive development as well as the development of sex-specific behaviors, such as toy preference or cognitive differences.

Credit: istockphoto.com

What’s more, the method will allow researchers to look at how early disruption of the endocrine system affects long-term maturation, a growing concern among physicians.

Surprisingly little is known about hormone levels during human infancy. Previous human research has focused on the measurement of hormones in blood, urine and saliva. The new data are the result of using fecal samples collected from cotton diapers. With this novel approach, the researchers successfully measured the fecal levels of estradiol, a type of estrogen.

The well-known importance of estradiol’s role in postnatal development of the body, brain and behavior has in recent years raised specific concerns about how exogenous estrogens, or environmental estrogens, such as those found in soy, fruits and vegetables, plastics and common household items, affect lifelong health.

“The development of robust, noninvasive methods to measure these hormones in infants allows us to further investigate the association between postnatal hormone production and the development of sex-specific biology and behavior,” says Emory anthropologist Michelle Lampl, senior author of the paper.

“The development of an assay to measure estrogen from diapers might initially strike one as unnecessary or strange, but the need is real,” says Sara Berga, chair of gynecology and obstetrics at Emory’s School of Medicine. “We understand very little about the hormonal dynamics that occur during early development precisely because we lack a reliable way to track hormones in neonates and very young children. Having a way to track this critical hormone that influences behavior and the development of many important tissues, including the brain, will allow us to understand normal. This really is a great leap forward.”

The paper’s authors include anthropologist Amanda Thompson at the University of North Carolina, Chapel Hill; Emory anthropologist Patricia Whitten; and Michael Johnson of the University of Virginia Health System.

Previous studies in primates have shown a close parallel between fecal levels of estradiol and serum values. Likewise, a comparison of fecal steroid levels between the study infants and previous studies of human adults shows an overlapping pattern, a pattern that is also seen in infant serum when compared with adult serum.

“These observations are the first report of human infant fecal estradiol levels and they provide a new tool for investigating early human development,” Lampl say, who also serves as associate director of the Emory/Georgia Tech Predictive Health Institute. “Because infant diapers are plentiful, fecal samples can be collected frequently and over a long period of time. Future longitudinal studies will allow the association between fecal levels of steroids and physiological measures to be assessed, and expand our understanding independent of serum measures.”

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