Poster Presentation ESA-SRB-APEG-NZSE 2022

Endometriotic chocolate cysts contain viable cells of endometrial origin: implications for endometriosis recurrence and infertility (#430)

Meaghan Griffiths 1 2 , Brooke Backman 1 2 , Fatima Figueiredo 1 2 , Martin Healey 1 2 3 , Keryn Harlow 1 2 3 4 , Claudia Cheng 1 2 3 , Charlotte Reddington 1 2 3 , Georgie Prewer 1 2 , Brodie Bilston 1 2 , Peter Rogers 1 2 , Jacqueline Donoghue 1 2
  1. Department of Obstetrics and Gynaecology, University of Melbourne, Parkville, Victoria, Australia
  2. Gynaecology Research Centre, Royal Women's Hospital, Parkville, Victoria, Australia
  3. Gynaecology Endometriosis and Pelvic Pain Unit, Royal Women's Hospital, Parkville, Victoria, Australia
  4. Fertility Associates, Christchurch, New Zealand

Endometriosis is a chronic, estrogen dependent disease affecting 11% of reproductive aged adolescents and women. Ovarian endometrioma, or chocolate cysts, are a common subtype of endometriosis yet, our understanding of their origins and pathogenesis is limited. Endometrioma are filled with a chocolate brown fluid believed to arise from the endometrial tissue lining the cyst wall haemorrhaging. Endometrioma are associated with reduced fertility. Their presence and growth is commonly detected by ultrasound or MRI, and treated by a laparoscopic ovarian cystectomy. However, endometrioma recurrence is common (46% of patients within 3-years), with 40% presenting with more severe endometriosis. The origins, nature, and mechanisms of endometrioma fluid production are unknown, but may contain live cells which contribute to recurrence in the event of cyst rupture. Elucidating the cellular make-up of endometrioma fluid is critical for furthering our understanding of endometrioma, and endometriosis-related infertility.

For this study, cystic fluid was collected from endometriomas via aspiration methods during surgery (n=7 patients) followed by dilution in PBS and serial filtration through 100µm, 40µm, and 10µm filters.  Each filtrate was pelleted, washed with PBS, and cultured as monolayers or in 3D Matrigel™ domes.  Cellular colonies and organoids appeared within 5-10 days. Immunophenotyping analysis confirmed CD10-positive stromal cells, cytokeratin-positive epithelial cells, and CD68-positive macrophages were present in endometrioma fluid. Other cell types observed included vimentin-negative myofibroblast-like cells, elongated cells with nerve-like projections and cobblestone colonies of endothelial-like cells.

These findings demonstrate endometrioma fluid contains a plethora of viable cells including CD10- and cytokeratin-positive cells that may be of endometrial origin.  Future work will include isolating cells from endometrioma fluid and cyst wall to determine cellular origin linkages using single cell transcriptomics. Uncovering the origins of endometrioma and their contents is critically important for enhancing our understanding of endometriosis and its impact on fertility.