Johns Hopkins animal study reveals sex-specific patterns of recovery from newborn brain injury

PUBLIC RELEASE DATE:

30-Jan-2014

Contact: Ekaterina Pesheva epeshev1@jhmi.edu 410-502-9433 Johns Hopkins Medicine

Physicians have long known that oxygen deprivation to the brain around the time of birth causes worse damage in boys than girls. Now a study by researchers from the Johns Hopkins Children's Center conducted in mice reveals one possible reason behind this gender disparity and points to gender-specific mechanisms of brain repair following such injury.

The results of the study, to appear in the February issue of the journal Neuroscience, show that inherent differences in the way newborn brains react to the sex hormone estradiol may be behind the sex-specific response to brain damage and cell repair.

"Our observations reveal intriguing differences in the way male and female brains respond to injury following oxygen deprivation and in the manner in which they recover following such injury," says lead investigator Raul Chavez-Valdez, M.D., a neonatologist at the Johns Hopkins Children's Center.

In addition, the researchers say, neurons in male and female brains undergo different type of cell death following oxygen deprivation that may be due to the presence of certain receptors that trigger sex-specific pathways of cell demise.

Lastly, the scientists say, their results clarify an earlier observation that the brains of male mice, while sustaining worse damage overall, tend to respond better to certain types of therapies that halt neuronal cell death.

The findings, Chavez-Valdez says, underscore the need to explore questions about gender differences in all studies, including those conducted in animals, infants and children. Answering these questions in this case could prove to be a stepping stone toward finding precisely targeted, gender-based therapies to stimulate brain cell preservation and recovery, the team says.

"Our findings show just how important gender-specific research is. Not only are sex differences a powerful player in the pathology and course of disease, but our results indicate that such differences begin to emerge very early in life, in the very first days of birth and, indeed, perhaps long before that," says senior study investigator Frances Northington, M.D., a neonatologist at the Johns Hopkins Children's Center.

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Johns Hopkins animal study reveals sex-specific patterns of recovery from newborn brain injury