October 29, 2004

SIU Med School Researchers Report Estrogen Findings at National Meeting

Research scientists at Southern Illinois University School of Medicine are reporting the lack of a positive effect of hormone replacement therapy in various clinical studies of patients may be due to ignoring the importance of the natural cyclical nature of the estrogen hormone.

The principal investigator of the study, Mary McAsey, Ph.D., assistant professor of obstetrics and gynecology at SIU in Springfield, presented the research this week at the Society for Neuroscience annual meeting in San Diego.

"This study was designed to look at the long-term effects of constant estrogen, the way the hormone is prescribed for women, because recent clinical studies have not found a positive effect of hormone therapy in the reduction of the incidence of neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases," McAsey explained.

The SIU study suggests that cyclic treatment with estrogen may maximize the positive effects of hormone therapy (HT) and avoid harmful effects. Unlike constant treatment used for HT, cyclic treatment resembles how estrogen is normally produced in a woman’s body, in combination with progesterone, during her reproductive years.

McAsey and her colleagues looked at proteins that are important for repair and function of neurons produced by the brain in both estrogen-treated and untreated mice. Estrogen stimulates neurons directly and also stimulates support cells, called glia, to produce proteins that bring nutrients into the neuron.

Previous studies, including epidemiologic studies involving review of patient records, have shown that HT decreases the risk and progression of many chronic neurological diseases such as Alzheimer's and Parkinson's diseases. In addition, several studies using animal models have consistently shown that estrogen can help repair damaged neurons.

"Estrogen treatment is currently used for the relief of symptoms of menopause such as osteoporosis and hot flashes. But it is not being used for treatment in a way that could be protective of the brain," said McAsey.

In the SIU study, female mice were given estrogen and their brains later examined. After five days, the estrogen-treated mice produced more proteins that are important for repair and neuronal function. However, with continuous estrogen treatment over several weeks, this effect was no longer present. At the end of the experiment, the mice that did not receive estrogen showed an elevation of a brain protein associated with the negative aspects of brain aging, while estrogen-treated mice did not.

"This suggests that estrogen hormone therapy may decrease the negative aspects of brain aging," explained McAsey.

The team will continue their research and now look into optimizing the dose and timing of administration of estrogen in order to maximize the beneficial effects in the brain.

The study was funded by the Illinois Department of Public Health Alzheimer's Disease Research Fund and an SIU Excellence in Academic Medicine grant awarded by the medical school.

Other researchers participating in the project were Robert Struble, Ph.D., associate professor of pathology and psychiatry and SIU's Center for Alzheimer's Disease and Related Disorders; Craig Cady, Ph.D., assistant professor of biology at Bradley University in Peoria; and Britto Nathan, Ph.D., associate professor of biological sciences at Eastern Illinois University in Charleston.

McAsey joined the SIU faculty in 1996. She completed a two-year postdoctoral fellowship in reproductive endocrinology at The University of Tucson (1996). She earned her doctorate at the University of Arizona in Tucson (1994) and her master’s and bachelor’s at the University of Wisconsin in Oshkosh (1978, 1975).

Struble joined the SlU faculty in 1988. He earned his doctorate and master's at the University of California at Riverside (1976, 1973). He earned his bachelor's at Claremont Men’s College in California (1969).

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