PELVIC pain in women with endometriosis may be caused primarily by a type of white blood cell called macrophages that have been modified because of the condition, according to a new study. The findings could pave the way for the creation of much needed non-hormonal drugs to treat endometriosis, which is believed to affect around 176 million women worldwide.
Currently, there is no means of curing endometriosis. While conventional hormonal treatments can relieve symptoms, they can cause side effects such as suppressing fertility. “We are trying to find non-hormonal solutions,” outlined senior study author Dr Erin Greaves, University of Edinburgh, Edinburgh, UK.
Previous research had identified the major role macrophages play in the onset of endometriosis, including assisting growth of the lesions and driving the development of their blood supply. These cells have also been shown to help nerves grow in the lesions. The team therefore sought to understand the mechanisms that lie behind the macrophages role in causing pain associated with endometriosis. “If we can learn about the role of macrophages in endometriosis, then we can distinguish them from healthy macrophages and target treatment to them,” explained Dr Greaves.
In the large numbers of macrophages that are attracted to and contained in endometriosis lesions, signals are generated by the disease environment that alter their function. In the study, the cell cultures of disease-modified macrophages were examined by the team, revealing that these cells released more of the growth hormone insulin-like growth factor-1 (IGF-1). It was also observed that IGF-1 levels were higher in pelvic cavity tissue from women with endometriosis compared with those without the condition, and this corresponded to their pain scores.
The team then showed that nerve cell growth and activation was promoted by adding IGF-1 from macrophages through further cell culture experiments. Finally, in a mouse model, they prevented the hormone’s activity by blocking the cell receptor for IGF-1, finding that this “reverses the pain behaviour observed in mice with endometriosis.”
It is hoped these new insights into macrophages activity in relation to endometriosis will ultimately help towards finding a cure to endometriosis, a condition which can adversely affect the lives of women in many ways, such as persistent inflammation, pain, and infertility.