Christel Meuleman

The endometrium, which is of crucial importance for reproduction, undergoes dynamic cyclic tissue remodeling. Knowledge of its molecular and cellular regulation is poor, primarily owing to a lack of study models. Here, we have established a novel and promising organoid model from both mouse and human endometrium. Dissociated endometrial tissue, embedded in Matrigel under WNT-activating conditions, swiftly formed organoid structures that showed long-term expansion capacity, and reproduced the molecular and histological phenotype of the tissue's epithelium. The supplemented WNT level determined the type of mouse endometrial organoids obtained: high WNT yielded cystic organoids displaying a more differentiated phenotype than the dense organoids obtained in low WNT. The organoids phenocopied physiological responses of endometrial epithelium to hormones, including increased cell proliferation under estrogen and maturation upon progesterone. Moreover, the human endometrial organoids replicated the menstrual cycle under hormonal treatment at both the morpho-histological and molecular levels. Together, we established an organoid culture system for endometrium, reproducing tissue epithelium physiology and allowing long-term expansion. This novel model provides a powerful tool for studying mechanisms underlying the biology as well as the pathology of this key reproductive organ.

BACKGROUND: Treatment of colorectal endometriosis is difficult and challenging. We reviewed the clinical outcome of surgical treatment of deeply infiltrating endometriosis (DIE) with colorectal involvement. METHODS: Review was based upon a literature search using following search terms: (1) 'surgery' and 'colorectal endometriosis', (2) 'bowel' and 'endometriosis' and 'surgery'. INCLUSION CRITERIA: clear explanation of surgical technique and follow-up data on at least one of the following items: complications, pain, quality of life (QOL), fertility and recurrence. RESULTS: Most of the 49 studies included complications (94%) and pain (67%); few studies reported recurrence (41%), fertility (37%) and QOL (10%); only 29% reported (loss of) follow-up. Out of 3894 patients, 71% received bowel resection anastomosis, 10% received full-thickness disc excision and 17% were treated with superficial surgery. Comparison of clinical outcome between different surgical techniques was not possible. Post-operative complications were present in 0-3% of the patients. Although pain improvement was reported in most studies, pain evaluation was patient-based in <50% (Visual Analogue Scale in only 18%). While QOL was improved in most studies, prospective data were only available for 149 patients. Pregnancy rates were 23-57% with a cumulative pregnancy rate of 58-70% within 4 years. The overall endometriosis recurrence rate in studies (>2 years follow-up) was 5-25% with most of the studies reporting 10%. Owing to highly variable study design and data collection, a CONSORT-inspired checklist was developed for future studies. CONCLUSIONS: Prospective studies reporting standardized and well-defined clinical outcome after surgical treatment of DIE with colorectal involvement with long-term follow-up are needed.