Engineering the <em>in vitro</em> ovarian follicle microenvironment: Developmental regulation by the culture matrix and translational approaches for human fertility preservationPublic Deposited
Improving cancer treatments are saving the lives of many young women, however these treatments often lead to premature infertility. The in vitro development of ovarian follicles would provide reproductive options to these women by supporting immature follicle growth following ovarian tissue cryobanking. In addition, the system provides a platform to investigate the process of folliculogenesis. A three-dimensional alginate-based follicle culture system has been developed that supports follicle development. This thesis characterizes the effects of the physical properties of this three-dimensional matrix on follicle development and presents the first investigation in the translation of the system to the human. Physical properties of microenvironments regulate cellular processes, and the regulation of follicle development by matrix physical properties was therefore examined. Mouse follicles were cultured in alginate matrices of varying physical properties, and responded to decreasing stiffness and density with improved follicle health as characterized by growth, antrum formation, theca formation, steroidogenesis, and oocyte quality. Further investigation of the signaling underlying disruption to follicle development in stiff matrices demonstrated disruption at the mRNA level. This study revealed, for the first time, a direct link between the biomechanical environment and follicle function, and suggests a novel non-hormonal mechanism regulating follicle development. These results not only lead to improvements to the in vitro culture system, but also have implications in follicle development and disease. Translation of the alginate culture system to the human will require identification of culture conditions supportive to human follicle development, and both human and monkey follicles were used in initial translational studies. Follicles survived, grew, produced increasing amounts of steroids, and maintained oocyte quality over 30 days in culture, which had not been achieved using previous approaches. Studies examined the effects of cycle stage at the time of isolation, matrix physical properties, and luteinizing hormone on follicle development, and demonstrated increasing follicle health when follicles were isolated during the follicular phase and cultured in 0.5% alginate without the addition of luteinizing hormone. These studies enable further translation of the alginate system and demonstrate the promise of the three-dimensional alginate approach in enabling fertility preservation following ovarian cryobanking for female cancer patients.