Written by Ilham Kanji, this article was selected as a winner of our 2023 High School Science Communication Challenge. Kanji is a student at Dubai College in Dubai, United Arab Emirates.

Endometriosis is a painful and unfortunately common disease affecting roughly one in ten women of reproductive age globally. It is characterized by the overgrowth of uterine lining tissue (or endometrium) in pelvic organs outside of the uterus, such as the fallopian tube or ovaries. While most endometrial tissue simply breaks down and bleeds out of the body during the menstrual cycle, endometrial tissue outside of the uterus cannot escape. Its retention in the body causes the build-up of painful cysts called endometriomas. The pain caused by endometriosis is chronic, severe, and — until now — seemingly incurable. In severe cases, endometriosis can even lead to infertility. While some hormonal therapies are used to shrink lesions, they often cause unwanted side effects like headaches and mood swings, as well as inhibiting menstruation. So, what actually causes the painful lesions associated with endometriosis, and how could they be controlled — or even cured?

Above: Endometriosis is characterized by an overgrowth of endometrial tissue outside of the inner wall of the uterus. This causes painful lesions called endometriomas, leading to chronic pain, inflammation, and sometimes infertility. Image courtesy of Cleveland Clinic.                                                 

IL-8: The Antagonist                                    

Interleukin-8 (IL-8) is a chemokine protein that induces the direct movement of leukocytes, cells that work to counteract the presence of dangerous foreign substances in the body. The protein is released from several cell types in response to foreign stimuli. It promotes inflammation, cell division, and angiogenesis, or the formation of new blood vessels.                  

But what does IL-8 have to do with endometriosis? Japanese pharmaceutical worker Ayako Nishimoto-Kakiuchi might have an answer. She and her team found that endometriosis tissue contains elevated levels of IL-8. This discovery could explain why women with endometriosis experience chronic pelvic pain: the elevated levels of IL-8 protein result in inflammation and a build-up of painful inflammatory cysts, causing severe chronic pain. This information prompted Nishimoto-Kakiuchi and her team to create an antibody that could inhibit the IL-8 gene — which, theoretically, could reduce the build-up of these painful cysts.                                          

AMY109 and Fighting IL-8                                      

The team developed a long-acting antibody known as AMY109 to inhibit IL-8. Its clinical effects were evaluated through testing on female macaques that were surgically induced with endometriosis. The results were overwhelmingly positive: of the eleven monkeys given the AMY109 antibody, all showed a roughly 50% reduction in the volume of nodular lesions and cysts. More importantly, neither male nor female macaques injected with the antibody experienced any harmful side effects like weight loss, menstrual cycle disruptions, or poor sperm quality, demonstrating the safety of the drug for mammalian use.                                       

There is still a long way to go before this antibody is suitable for human use, as human clinical trials are just beginning. Nonetheless, it is certainly a step in the right direction toward combatting a condition that has affected the lives of so many. Should this antibody prove to be a success in humans, it will be a revolutionary scientific discovery that will enable women affected by endometriosis to live near-normal lives without the burdens of chronic pain or infertility.

Above: Healthy endometrial tissue (without endometriosis). Image courtesy of New Scientist.