Advances In Endometriosis
While endometriosis is a common cause of infertility and chronic pelvic pain during lovemaking, its mechanism is not well understood. Yet, 5-10 million women in the U.S. alone are affected by this chronic disease.
Northwestern University's Serdar Bulun, M.D., George H. Gardner Professor of Clinical Gynecology at the Feinberg School of Medicine, has been researching the disease for 15 years, hoping to identify its causes. Bulun's team has now discovered genetic differences in the sufferers of endometriosis and even found which existing chemicals may help to treat the condition. A description of the team's findings from the past decade appears in the January 15th issue of the New England Journal of Medicine.
One of the chief discoveries made by Bulun's team is that the enzyme known as aromatase, which is responsible for estrogen production, is found in the endometrial tissue of women with the condition. In women without this condition, the endometrium does not contain this enzyme. Endometriosis is a condition in which tissue that mimics that which lines the uterus, the endometrium, is found outside the uterine cavity. Since this tissue contains aromatase, women with endometriosis will be found to have excessive estrogen in any of the organs on which the tissue is found, for instance on the ovaries. Bulun's team found that the protein SF1, which produces aromatase, remains active in endometriosis.
"Estrogen is like fuel for fire in endometriosis," Bulun said. "It triggers the endometriosis and makes it grow fast."
Breast Cancer Drugs
Based on his findings, Bulun began trials in 2004 testing various aromatase inhibitors, drugs which are in current use for hormonally responsive breast cancer, as a treatment for endometriosis. These drugs stop estrogen production and promote a greater response to progesterone. This treatment is believed to be an excellent option for women with perimenopause whose endometriosis is unresponsive to existing treatments, notes the researcher.
Bulun had a second finding during his long years of research: women with endometriosis have an inactive progesterone receptor. Progesterone action would have an important therapeutic effect on women with endometriosis, since this hormone would serve to block the growth of the excess migrating tissue. Because the progesterone receptor is shut down, the tissue remains in a state of inflammation and continues to reproduce.
It is Bulun's belief that the twin abnormalities of the presence of aromatase in endometrial tissue and the blockage of the progesterone receptor in women with endometriosis occur in response to defects incurred during early development of the embryo. He feels that these defects may be due to maternal exposure to toxins in the environment during early pregnancy.
This contention mirrors the findings of other research projects which have shown that dioxin, an environmental pollutant, and DES, a synthetic estrogen, may be culprits in the eventual development of endometriosis.
Bulun suggests that women may be born with the disease, or at least, predisposed at birth to have endometriosis. Says Bulun, "Maybe research can now be directed toward the fetal origins of the disease and raise the awareness of how the disease develops."