Immune System Studies.
For more than 30 years, staff of the Endometriosis Institute has been in the forefront of endometriosis research. Our studies indicate that in all women during the menstrual period, blood and fragments of shed endometrial tissues are transported through fallopian tubes into the abdomen. In healthy women, these misplaced cells are programmed to die (undergo apoptosis) and are removed by the cells of the immune system (macrophages).
In about 10% of women, apoptosis and the ability of macrophages to remove misplaced endometrial cells are impaired. The misplaced cells are allowed to survive and implant. Typically they implant on the peritoneal surfaces (lining of the abdomen), in the anterior and posterior cul-de-sacs (anterior is between the uterus and urinary bladder — posterior is between the uterus and rectum), on the ovaries, and on other abdominal organs.
Following implantation, endometrial cells divide, multiply, and form typical endometriotic lesions. Changes in endometrial apoptosis and in the immune system that lead to the development of endometriosis may be transmitted genetically from mother-to-daughter, or may be acquired as a result of the environmental effect on the immune system.
Our most recent studies indicate that the expression of pro-apoptotic genes in the endometrial cells in women with endometriosis is decreased and that expression of anti-apoptotic genes in the same cells is increased. Such changes would facilitate survival of misplaced endometrial cells and the development of endometriosis in affected women. They may also provide the rationale for new therapeutic approaches.