Endometriosis is a women's disease that affects 10-15% of all reproductive-aged women. Although no cure has been found for the disease, researchers seek to find out why some women develop endometriosis and which may be its effective treatment. Researchers from Tartu have completed a study that helps to get closer to explaining the causes of endometriosis.
Endometriosis is a disorder in which tissue that lines the inside of the uterus -- the endometrium -- grows and develops lesions outside the uterine cavity. This causes inflammation which in turn brings along chronic pelvic pain, painful intercourse or pain with urination and bowel movements, and often also infertility.
According to the Research Fellow of Reproductive Medicine at Tartu University Institute of Clinical Medicine and the Competence Centre on Health Technologies Merli Saare, nobody actually knows how many women suffer from the disease because it is not easy to diagnose. So far, there is no method for identifying endometriosis from a blood sample.
"Today, the disease is mainly diagnosed surgically. In general, patients have to undergo a laparoscopic procedure in which lesions are surgically removed from the abdominal cavity. Small pieces of this tissue are taken for histological analysis that helps to confirm the diagnosis," explained Saare.
Surgical removal of lesions relieves symptoms but does not cure the disease, which tends to recur. In addition to the fact that there is no effective treatment for endometriosis, researchers still do not know exactly which factors support the development of the disease or why some women have it and others do not.
The causes of endometriosis are studied by analysing the uterine mucosa and the tissue that has formed and grows in the abdominal cavity. Like any other endometrium-related diseases, also the menstrual cycle factors have to be considered while studying endometriosis. Women usually inform doctors of the day of their menstrual cycle when they go to surgery. However, this may not be accurate enough for determining the exact phase of the menstrual cycle, as Saare and her colleagues say in their research paper published in the journal Biology of Reproduction.
Their study, which is based on the analysis of endometrium samples taken from about 80 women, confirmed that the day of the menstrual cycle given by the women themselves and the molecular profile of their endometrium were often incompatible. Therefore, molecular tools are needed for more accurate classification of samples: by analysing RNA from the endometrium, researchers can assign exact dates to tissue samples and improve the quality of future research. "Our study helps to precisely determine the phase of the biopsy samples taken from the endometrium. This way we can avoid examining the endometrium in different phases of the cycle," explained Saare.
She is convinced that a breakthrough in establishing the causes of endometriosis is only a question of time, considering the modern technological potential. "All small steps and discoveries take us closer. If our studies become more precise and we are able to eliminate side factors, it is much easier to find causal changes of the disease."
In their study, the researchers used an advanced molecular tool beREADY, a test developed at the Competence Centre on Health Technologies and used in fertility clinics, which provides an opportunity to select the most appropriate day for embryo implantation. Research has shown that the test used for determining the genes that are important in endometrial maturation can also be beneficial in the molecular studies of the endometrium.