MULTISCALE TECHNOLOGIES FOR ENGINEERING AND CRYOPRESERVING OVARIAN TISSUES AND HUMAN IPSCs

Abstract

An estimated 9.8 million reproductive-age people with ovaries in the United States are impactedby fertility issues, oftentimes caused by the dysregulation of the tightly controlled process of ovarian follicle development. Impaired fertility can arise from disorders like polycystic ovarian syndrome (PCOS) or premature ovarian insufficiency (POI), which affect the function of the ovary, an integral reproductive organ that houses the ovarian follicles. POI can also negatively impact endocrine function, decreasing estrogen and leading to increased risk of osteoporosis, cardiovascular disease, and neurological disorders. Novel fertility preservation and restoration strategies, like ovarian tissue engineering, have emerged to address these effects of ovarian dysregulation and offer alternatives for those who wish to delay childbearing. Human induced pluripotent stem cells (hiPSCs) hold tremendous potential for tissue engineering and cell-based medicine, as they have the capacity of differentiating into ectodermal, mesodermal, endodermal, and germ cell lineages. In recent years, research into differentiating hiPSCs into cells like those that make up the ovary has garnered much interest, highlighting these cells as a promising source for ovarian tissue engineering and other types of cell-based medicine and research. This work addresses critical challenges associated with engineering ovarian tissue for reproductive and cellbased medicine: (1) engineering the microenvironment for the cell/microtissue and (2) cryopreservation of the cells/microtissues. To understand the microenvironment of the ovary for informed tissue engineering system design, we spatially characterize the micromechanical properties of ovarian tissue from domestic cats to reveal both elastic and viscoelastic property heterogeneities, correlating these findings with the distribution of key extracellular matrix (ECM) molecules. We then developed a novel cryopreservation technology to enhance cryopreservation of ovarian follicles and hiPSCs, using sand to seed ice in the extracellular solution at high subzero temperatures during cooling. Together, this work investigates multiscale strategies for advancing ovarian tissue engineering, contributing to the advancement of reproductive medicine approaches for treating infertility and related endocrine dysfunction.