The regeneration of the human endometrium and development of endometrial glands during the proliferative phase is critical in laying a fertile foundation for the subsequent receptive, secretory phase. This process is poorly understood and mostly unique to humans. As such, conventional animal models can rarely be used to study the remodelling of the human endometrium. The development of a physiologically relevant 3D co-culture model of the human endometrium is essential in uncovering the role of endometrial regeneration in determining female fertility or infertility. We hypothesised that human endometrial cells would migrate and proliferate within a 3D matrix, reflecting endometrial regeneration during the proliferative phase. Our aim was to develop a novel 3D co-culture model to investigate endometrial regeneration.
To establish the 3D model, a suitable matrix reflecting that in vivo was optimised. Primary human endometrial stromal and epithelial cells, as well as the endometrial epithelial cancer cell line, Ishikawa, were seeded into the 3D gel matrix and terminated at intervals to examine the migration and proliferation of cell types, and glandular development.
A collagen I-fibrin co-gel was optimised as a 3D matrix for the endometrial cells. Endometrial primary cells seeded into the 3D gel were sustained in culture for up to 20 days. Endometrial stromal cells elongated within the gel. While endometrial epithelial cells did not form glandular structures, Ishikawa cells seeded into the 3D gel proliferated, migrated and formed gland-like structures and a pseudostratified epithelial monolayer, identified by staining for cytokeratin.
The development of the 3D model of the human endometrium will enable the study of the complex processes involved in the establishment, proliferation and differentiation of endometrial cells, and formation of glands capable of achieving a receptive state. Further investigations utilising our 3D model will provide important insights into human endometrial development and female infertility.