An invisible disease

Micrograph showing the features of endometriosis. Image courtesy of Nephron, a Wikimedia Commons user

How do you tackle an invisible disease?

That is the challenge in diagnosing and treating endometriosis, a debilitating disease that affects at least 5 million American women of child-bearing age. March is endometriosis awareness month to highlight the lack of proper diagnosis and treatment options for patients. The nonprofit Worldwide EndoMarch is organizing marches around the world, including in the U.S., to take place on March 28.

What is endometriosis?

The endometrium is the uterine lining that is shed and regenerated during a woman’s monthly hormonal cycle. Endometriosis occurs when cells from the endometrial tissue spread beyond the uterus by a process called retrograde menstruation into other organs, such as the ovaries, Fallopian tubes, bowel and intestines. These extrauterine endometrial cysts respond to the monthly hormonal cycle, causing inflammation and scarring. Symptoms include painful cramps, heavy menstruation and digestive disorders. Endometriosis also causes infertility and can increase the risk of ovarian cancer or breast cancer.

Why is endometriosis called “invisible”?

A study by the National Institutes of Health revealed that one in 10 women who present no symptoms of endometriosis actually have the disorder. Therefore, the actual number of women with endometriosis is higher than the currently estimated 5 million. Moreover, the painful symptoms often are misconstrued as just bad cramps. The lack of sensitive diagnostic methods impedes timely diagnosis.

What biochemical factors are involved?

In endometriotic tissues, upregulated aromatase activity increases the level of estrogen, which causes excessive cell proliferation. Estrogen induces cyclooxygenase-2, which is necessary for the synthesis of prostaglandin E2, or PGE2, a mediator of inflammation. PGE2 further stimulates aromatase activity. Also, the endometrial cells are resistant to changes in progesterone (an antagonist of estrogen), because chromatin methylation leads to the suppression of Homeobox genes.

What are recent advances in the diagnosis and treatment of endometriosis?

Aromatase inhibitors and estrogen-receptor blockers (e.g., chloroindazole and oxabicycloheptene sulfonate) prevent estrogen-dependent signaling and inflammation. They could be effective alternatives to traditional synthetic progesterone treatments whose efficacy is highly variable.

The National Institute of Child Health and Human Development is preparing a multisite clinical trial to detect endometriosis based on a method developed by Linda Giudice and colleagues at the University of California, San Francisco. The researchers determined both the extent and severity of the disease by picking out unique expression pattern of genes involved in immune activation, steroid and thyroid hormone signaling and metabolism, and growth factor signaling

Indumathi Sridharan Indumathi Sridharan earned her bachelor’s degree in bioinformatics in India. She holds a Ph.D. in molecular biochemistry from Illinois Institute of Technology, Chicago. She did her postdoctoral work in bionanotechnology at Northwestern University.