Technologies for the Production of Fertilizable Mammalian Oocytes

Abstract

Women affected by ovarian pathologies or with cancer can usually preserve fertility by egg/embryo freezing. When oocyte retrieval is not feasible, the only option available is ovarian tissue cryopreservation and transplantation. The culture of follicles isolated from fresh or cryopreserved ovaries is considered still experimental, although this procedure is considered safer, because the risk of unintentional spreading of cancer cells eventually present in cryopreserved tissue is avoided. Animal and human small follicles can be cultured in vitro, but standardized protocols able to produce in vitro grown oocytes with the same developmental capacity of in vivo grown oocytes are not available yet. In fact, the different sizes of follicles and oocytes, the hormonal differences existing between mono- (e.g., human, goat, cow, and sheep) and poly-ovulatory (rodents and pig) species, and the incomplete identification of the mechanisms regulating the oocyte–follicle and follicle–ovary interrelationships affect the outcome of in vitro culture. From all these attempts, however, new ideas arise, and the goal of assuring the preservation of female reproductive potential appears a more realistic possibility. This review surveys and discusses advances and challenges of these technologies that, starting from a simple attempt, are now approaching the biosynthesis of a functional engineered ovary.

The (endo)cannabinoid signaling in female reproduction: What are the latest advances?

“…In mammals, oocytes originate from actively proliferating primordial germ cells that enter meiosis and arrest at the germinal vesicle (GV) stage. Their very low number justifies the many ongoing attempts to increase their population in vitro, although good results in terms of live births have been obtained only for mouse oocytes [53]. In rodents, meiosis and follicle formation start during the first few days after birth, while in primates during fetal life.…”

Genetic instability and anti-HPV immune response as drivers of infertility associated with HPV infection

“…Female infertility, in the context of assisted reproductive technology, is split into several etiologies including dysfunctions of reproductive apparatus: tubal factor, ovulatory dysfunction, diminished ovarian reserve, endometriosis and uterine factor [ 5 ]. The other common causes are advanced age, sexually transmitted diseases and immunological factors [ 6 ]. Male-infertility-associated factor(s) together with the abnormal semen parameters are identified in up-to 50% of infertile couples [ 7 ].…”

Optimization of Porcine Ovarian Follicle Isolation Methods for Better Developmental Potential

“…[1][2][3][4][5] Moreover, in the last decade, iso-lation and in vitro maturation of follicles have been considered as a potential alternative to restore fertility in a female who has abnormal oogenesis and in cancer patients who undergo gonadotoxic chemotherapy. [6][7][8][9] Moreover, in the recent years the scientific community started to focus its research activities on reproductive tissue engineering (REPROTEN), as defined by Amorim. 10 In this framework, there is the need of the definition of standard optimized protocols for the follicle extraction and also a matrix to support the ovarian follicle growth in vitro.…”