The University of Warwick has discovered the role of immune cells called macrophages in causing pain in endometriosis, potentially opening new opportunities for pain relief for the condition.
The Greaves lab, now part of Warwick Medical School at the University of Warwick, along with collaborators at the University of Edinburgh, discovered that the cells play a role in stimulating the growth and activity of nerve cells in the condition, leading to increased sensitivity to pain in the pelvic region.
Macrophages allegedly adapt their functions according to local signals and so become modified by disease. They are drawn more to the endometriosis lesions and are also found in high numbers inside the lesions themselves.
Using a cell culture of these diseased-modified macrophages, the scientists observed increased production of the insulin-like growth factor-1 (IGF-1). Applying this onto nerve cells grown in culture, they found that this encouraged the nerves to grow and also activated them, demonstrating that production of IGF-1 by macrophages plays an important role in generating pain in endometriosis.
Previous studies have shown that macrophages can be involved in other types of chronic pain, but this is the first time that it has been shown to be linked to endometriosis.
Lead author, Dr Erin Greaves from Warwick Medical School said that the condition is sometimes considered a ‘hidden disorder’ because of a “reluctance to discuss what can be passed off as ‘women’s problems’.”
She also explained, “Hormonal solutions rely on suppressing ovarian function but are not ideal as they can cause unwanted side effects, and prevent the user from becoming pregnant. We are trying to find non-hormonal solutions.”
Around 176 million women worldwide suffer from endometriosis, in which cells like the internal lining of the uterus (endometrium) grow outside of it in the form of lesions, typically in the pelvic cavity.
It can cause significant pelvic pain and is associated with infertility for some women with the condition. Currently, treatment options are limited to surgical removal of lesions or medical management to suppress ovarian hormone production, so new non-hormonal treatments are desperately needed.