According to the Endometriosis Foundation of America, more than 176 million women and girls worldwide suffer from endometriosis. But the exact cause of the condition is unknown. Now, researchers from the Massachusetts Institute of Technology say they have uncovered cellular activity that may provide a better understanding of the mechanisms behind the condition.

This is according to a study recently published in the journal Science Translational Medicine.

The research team, led by Michael Beste of the Department of Biological Engineering at the Massachusetts Institute of Technology (MIT), says their findings may also help scientists create better drugs for the condition and help clinicians determine the most effective treatment for patients.

Furthermore, the investigators say the findings could open the doors for development of a "patient stratification system" similar to what is already used for patients with breast cancer. This involves treatments being individually developed to the molecular profile of patients' tumors.

What is endometriosis?

Endometriosis is a condition in which endometrial tissue, which lines the inside of the uterus, is found outside. Most commonly, tissue is usually trapped in the pelvic area or lower abdomen, but it can also be found in other areas of the body.

The researchers say the cause of the condition is unknown.

"We know there is a genetic component, we know there is an environmental component, and we know there is an inflammatory component. But it's very difficult to say for individual patients what particular sequence of events led to particular symptoms," says Beste.

Symptoms of the condition include painful or heavy periods, pain in the lower abdomen, pelvis or lower back, and fertility problems.

However, symptoms can vary significantly for each woman, and some women may not have any symptoms at all. The research team says this can make the condition difficult to study.

"The delay to a conclusive diagnosis can range anywhere from 3 to 15 years. There's a real need in the field to improve our understanding of both the basic biology and the clinical manifestations of the disease to better treat and improve the quality of life of affected women," says Beste.

Women with endometriosis can be treated with hormones that trigger a state similar to menopause. But the investigators note that this type of treatment is not ideal for patients who want to become pregnant, and it is not always reliable.

Surgery is also another option for patients. This involves removing the trapped tissue. But the investigators say that this treatment is not permanent and some patients may need to have several procedures over their lifetime.

Cykotine pattern uncovered

For the study, the research team analyzed peritoneal fluid (liquid made in the abdominal cavity) of 77 women who had varying symptoms of endometriosis.

The researchers measured 50 proteins for each sample, including cykotines. These are inflammatory compounds that regulate the body's response to agents that might cause infection.

However, cykotines can also trigger inflammation when no pathogens are present, which is what they do in the case of endometriosis.

In the peritoneal fluid samples, the investigators discovered a pattern of activity involving 13 cykotines that is linked to ovarian and rectovaginal lesions. The researchers also discovered that the pattern negatively correlated with fertility of the patients.

Further investigation revealed that a key regulator in this newly discovered pattern is c-jun. This is a protein that drives inflammation, and one that has previously been linked to endometriosis.

The investigators also found that the pattern consists of molecules that are secreted by macrophages - immune cells that "eat" pathogens.

More research needed

The research team now plans to find out what triggers this immune response. They are looking to analyze tissue from endometriosis patients who suffer infertility and those who have deep infiltrating lesions that affect the colon and other organs.

The investigators are also planning to carry out a long-term study that tracks patients from the first symptoms of endometriosis.

They stress that these studies could open doors to new drug treatments for endometriosis and provide a better understanding of the mechanisms behind the condition.

Linda Griffith, of the Center for Gynepathology at MIT and one of the study authors, says:

"This paper isn't to say we discovered the answer. We're trying to start a conversation with a broad translational science community about this because it is such a terrible disease.

We found something really interesting, but it's only the tip of the iceberg, and if other clinicians are interested in setting up a similar study with their patients, we're happy to talk about collaborating with them."

Last year, Medical News Today reported on a study suggesting that exposure to pesticides may increase the risk of endometriosis.