Innovations in Treating Endometriosis
Endometriosis cells are abnormal in 3 ways:
They produce abnormally high levels of estrogen
They possess abnormally high levels of estrogen receptors
They produce abnormal levels of prostaglandins and cytokines (inflammation molecules that cause pain, infertility, and other problems.
Endometriosis implants can also stimulate growth of nearby blood vessels to “feed” the implant, as well as growth of nerve cells to provide sensation to the implant.
Advancing the Treatment for Endometriosis: Aromatase Inhibitors and Progesterone Receptor Blockers
The key for advancing the treatment of endometriosis lies in finding ways to selectively eliminate or suppress endometriosis cells. Promising new treatments involves aromatase inhibitors (medications that block estrogen production in cells) and progesterone receptor blockers.
Endometriosis: Abnormal Cells Within and Outside the Uterus
Endometriosis implants possess abnormal amounts of an enzyme called “aromatase”. This enzyme converts estrogen-precursor molecules to estrogen. Endometriosis implants also have high levels of estrogen receptors.
The endometrium, or uterus lining, also contains abnormal amounts of aromatase and estrogen receptors in women with endometriosis.
Endometriosis: a Self-Perpetuating Process
Endometriosis implants can both synthesize estrogen independent of the ovarian hormones; and they are more sensitive to estrogen. They are analogous to self-sustaining, self-perpetuating machines.
Endometriosis located outside the uterus can re-generate itself and spread through self-stimulation, whether or not the uterus and ovaries are present.
This explains why some women who have hysterectomy for endometriosis have recurrent pain after total hysterectomy. Hysterectomy and oophorectomy (removal of ovaries) “debulks” endometriosis tissue present in the uterus and ovaries, but it does not remove endometriosis implants present outside the uterus.
Aromatase Inhibitors Can Target Endometriosis Located Outside the Uterus
Aromatase inhibitors (AI’s. e.g. letrozole and anastrozole) block the enzyme, aromatase, essential to estrogen production. Thus AI’s can target endometriosis cells anywhere in the body, be they on on nerves outside the uterus, the ovaries, or inside the uterine muscular wall (this type of endometriosis is called “adenomyosis” and is responsible for pain and heavy bleeding with menses).
Aromatase inhibitors should be used in conjunction with either combined oral contraceptives or continuous progesterone therapy because used alone, they do not prevent ovulation.
Progesterone Receptor Blockers
Medications that block progesterone receptors (e.g. mifepristone and ulipristal acetate) can inhibit endometriosis by inhibiting ovulation and therefore cyclic production of estrogen. These medications are not widely available in the United States, and so have not found a consistent place in treatment of endometriosis for American women.
