Past studies have suggested that estrogens may improve brain functioning, possibly by blocking neural cell death caused by oxidation. However, some studies have suggested that tamoxifen, which blocks estrogens stimulatory effects in breast cancer, may block estrogens beneficial effects on the brain and possibly contribute to cognitive decline.
To study tamoxifens effect on brain chemistry in elderly women, Ernst and his coworkers used a brain imaging technique to compare levels of myo-inositol, a chemical that increases in response to brain injury, among 16 breast cancer survivors who had been treated with tamoxifen for at least 2 years, 27 healthy women who had been treated with preventive estrogen replacement therapy for at least 2 years, and 33 healthy women who had not received any treatment. All of the women were between the ages of 65 and 80 and did not have any neurologic diseases.
The researchers found that women who had been treated with tamoxifen had lower levels of myo-inositol in the brain than the untreated women. Women who took estrogen also had lower levels of the chemical. Myo-inositol levels were lowest among women who had been treated with tamoxifen for longer periods of time.
The authors conclude from the lower levels of myo-inositol in women treated with tamoxifen or estrogen that both [tamoxifen and estrogen] may be neuroprotective and may have favorable modulatory effects on aging. They note, however, that future studies are necessary to look at t
Contact: Linda Wang
Journal of the National Cancer Institute