November 2, 2012

Toxin provides endometriosis clues

Environmental toxins may contribute to endometriosis-related infertility by disrupting endometrial response to progesterone.

(iStock)

Endometriosis, a common and debilitating condition that can cause infertility and severe pelvic pain, occurs when the cells that line the uterus (endometrium) grow outside the uterus. Coordination of hormones such as estrogen and progesterone and other signaling molecules, like the endocannabinoids, is critical to normal functioning of the endometrium.

Kevin Osteen, Ph.D., professor of Obstetrics and Gynecology, Kaylon Bruner-Tran, Ph.D., associate professor of Obstetrics and Gynecology, and colleagues are investigating whether exposure to environmental toxins, like dioxin, may disrupt the hormonal and chemical signaling in the endometrium, and potentially contribute to endometriosis.

In the October issue of Fertility and Sterility, the investigators report low levels of expression of the endocannabinoid receptor CB-1R in tissues from women with endometriosis in contrast to its abundant expression in healthy endometrium. Using cultured endometrial cells, they found that dioxin exposure inhibits the ability of progesterone to induce CB1-R expression.

Since progesterone and endocannabinoids are critical to pregnancy, these findings suggest that environmental toxins like dioxin may contribute to endometriosis-related infertility by disrupting endometrial response to progesterone.

The research was supported by grants from the National Institute for Environmental Health Sciences (ES014942), the National Institute for Child Health and Human Development (HD052666) and the National Center for Research Resources/National Center for Advancing Translational Sciences (RR024975) of the National Institutes of Health, and The Endometriosis Association.