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Fertility preservation strategies
Published in David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham, Textbook of Assisted Reproductive Techniques, 2017
Stine Gry Kristensen, Claus Yding Andersen
For the future, new strategies should be optimized and investigated. IVM of early follicle stages from which mature fertilizable oocytes could be retrieved is one way to avoid the risk of transmitting malignant cells when re- implanting frozen–thawed ovarian tissue. This has been achieved in mice (111), and a metaphase II oocyte was retrieved from a primate follicle cultured from a preantral follicle (112). In humans, long-term culture of preantral follicles to early antral stages has been achieved (80,113); however, research is still required to establish this as a possible clinical application. Another approach suggests the transfer of isolated human primordial follicles into an artificial ovary—a specially created scaffold—so as to provide an alternative way of restoring fertility in patients who cannot benefit from transplantation of cryopreserved ovarian tissue (114,115).
Construction and cryopreservation of an artificial ovary in cancer patients as an element of cancer therapy and a promising approach to fertility restoration
Published in Human Fertility, 2022
Jing Chen, Plamen Todorov, Evgenia Isachenko, Gohar Rahimi, Peter Mallmann, Vladimir Isachenko
Artificial ovaries can be considered as a response to the issues considered above. They comprise a collection of individual follicles in which each one contains a single oocyte responsible for secreting the hormones necessary for oocyte maturation. The initial and crucial step in constructing an artificial ovary is to extract the follicles from ovarian tissue enzymatically, and after isolation, immediately embed them in a 3-dimensional (3 D) culture system together with other ovarian cells. The follicle 3 D culture is a biomaterial-based scaffold and has crucial benefit of maintaining the spherical structure of ovarian follicles. This so-called artificial ovary is transplanted into patients to replace ovarian tissue in order to preserve fertility and recover hormone function (Cho et al., 2019). The scaffold must therefore be degradable so that follicle development, migration, proliferation, and angiogenesis can occur (Kim, Tamadon, et al., 2017; Kim, Kim, et al., 2017).
Three-dimensional bioprinting of artificial ovaries by an extrusion-based method using gelatin-methacryloyl bioink
Published in Climacteric, 2022
T. Wu, Y. Y. Gao, J. Su, X. N. Tang, Q. Chen, L. W. Ma, J. J. Zhang, J. M. Wu, S. X. Wang
An artificial ovary typically comprises a supporting bioscaffold and follicles at different developmental stages. Conventional methods for the fabrication of artificial ovaries involve encapsulating ovarian follicles in plasma clots, synthetic hydrogels or natural polymers, such as collagen, fibrin and alginate [10–13]. Microfluidic chips have also been created for in vitro culture of ovarian follicles [14–16]. However, they are limited to small-scale production and are very unlike real ovaries. In fact, in the majority of studies, artificial ovaries are replaced with ovarian follicles, which are the functional units of the ovary. Overall, accurately mimicking the complex cellular compartmentalization, dynamic extracellular matrix and mechanical properties of a real ovary in an engineered ovary is extremely challenging.
Fertility preservation in ovarian cancer patients
Published in Gynecological Endocrinology, 2021
Maria Luís Santos, Ana Sofia Pais, Teresa Almeida Santos
In ovarian cancer patients, fertility preservation options are very limited. Oocyte cryopreservation is still the best option and the only one established along with embryo cryopreservation. Fertility preservation surgery must be carefully thought-through and involve a multi-disciplinary assessment of the chance of recurrence. The artificial ovary and in vitro maturation of oocytes is a very attractive option in these patients, but further milestones have to be achieved. Ovarian tissue cryopreservation will not be an option as long as the risk of reseeding cancer cells is not fully eliminated. Ovarian protection from chemotherapy using gonadotrophin releasing hormone (GnRH) agonists or other options seem to be appealing but can only be recommended when its value is recognized by high quality evidence studies.