In vitro maturation of human oocytes

Immature oocyte retrieval followed by in vitro maturation (IVM) opens a new horizon for modern assisted reproductive technologies (ART). Recent studies in IVM make it a feasible alternative to in vitro fertilization. Antral follicle count is correlated with the pregnancy rate, so women with polycystic ovarian syndrome or polycystic ovaries are the best candidates for IVM. IVM can also be offered to women at risk of ovarian hyperstimulation syndrome or poor responders. From the available information, IVM is a safe procedure and does not increase congenital anomalies or pregnancy complications. Further research is necessary in order to apply this technique to other patients.     

人类未成熟卵母细胞体外成熟研究进展

在卵母细胞成熟过程中第二信使、激活素/抑制素、巨噬细胞炎症因子-3α、溶血磷脂酸有重要作用；未成熟卵体外成熟受是否给予促性腺素/绒毛促性素刺激、患者年龄、取卵时卵泡大小及所处月经周期等多种因素影响；体外培养系统中添加促性腺素、绒毛促性素、患者血清、适宜的糖和氨基酸及适当氧浓度是有益的,是否加共培养细胞尚不明确,培养时间倾向缩短至28h。未成熟卵母细胞体外成熟已成为一项热门的辅助生殖技术,有广阔的应用和发展前景。     

In vitro maturation of Mammalian oocytes: outcomes and consequences

The application of in vitro maturation (IVM) of oocytes as a technology to assist animal production and clinical infertility treatment remains poor because of the reduced developmental competence of oocytes after IVM, despite several decades of research. Reduced meiotic maturation rates, fertilization rates, and blastocyst production reveal short-term developmental insufficiency of oocytes when compared with in vivo-matured counterparts. However, there is an increasing body of evidence that demonstrates the capacity of IVM efficiency to be improved, some of which is reviewed here. Of more concern is the role that IVM of oocytes may play in causing or accentuating long-term development and health of fetuses and neonates after in vitro production of embryos and embryo transfer. This is a largely unexplored area, yet the application of such techniques, especially the safety of clinical IVM, is significant and requires monitoring before acceptance as a routine procedure.     

In vitro maturation of oocytes as a strategy for fertility preservation

In vitro fertilization and embryo cryopreservation are regarded as the only established method for the preservation of fertility in female cancer patients. However, a possible delay in the treatment of cancer and exposure to supraphysiologic estrogen levels caused by ovarian stimulation raise concerns for patients and physicians. In vitro maturation avoids treatment delay or exposure to increased estradiol levels associated with in vitro fertilization. In vitro maturation combined with embryo or oocyte vitrification provides options that have been unavailable earlier, such as immature oocyte collection in the luteal phase, for some patients and improves the services provided by a fertility preservation program.     

In vitro maturation of oocytes via the pre-fabricated self-assembled artificial human ovary

Purpose  

Create a 3-Dimensional artificial human ovary to mature human oocytes.     

In vitro maturation of human preovulatory oocytes reconstructed by germinal vesicle transfer

OBJECTIVE: To describe a micromanipulation-electrofusion procedure for transferring germinal vesicles (GVs) between immature human oocytes. DESIGN: Pilot study to assess oocyte maturation after an invasive micromanipulation procedure. SETTING: Research laboratory at a university medical center. PATIENT(S): Immature oocytes were discarded from intracytoplasmic sperm injection (ICSI)-IVF cycles of patients 23-48 years of age. INTERVENTION(S): Initially, GV removal and transfer were performed on the same oocyte; these "self-reconstructed" oocytes were then cultured in vitro for up to 50 hours and examined periodically for maturation as judged by the extrusion of the first polar body. In a second study, GVs from oocytes of "old" patients (>38 years old) were successfully transferred into enucleated immature oocytes of "young" patients (<31 years old). MAIN OUTCOME MEASURE(S): Extrusion of the first polar body was monitored in "reconstructed" and control oocytes; karyotypes also were analyzed at meiosis II. RESULT(S): From 48 oocytes from old patients, 12 GVs were successfully removed, transferred, and fused into previously enucleated oocytes from young patients. After in vitro culture, 7 of these "reconstructed" oocytes matured to meiosis II, a maturation rate not significantly different from that observed in nonmanipulated controls. A normal, second meiotic metaphase chromosome complement was observed in 4 of 5 reconstructed oocytes. CONCLUSION(S): Normal meiosis can occur after the transfer of a GV into an enucleated host oocyte. Germinal vesicle transfer may be a valuable research procedure that generates cell models to characterize the cytoplasmic-nuclear interplay for cell cycle regulation, maturation, and fertilization in the human oocyte; it also may be a potentially attractive alternative to oocyte donation.     

In vitro maturation of ovine oocytes using different maturation media: effect of human menopausal serum

Objective  

To compare the effect of human menopausal serum with estrous sheep serum, estrous goat serum, ovine follicular fluid and bovine follicular fluid on in vitro maturation, in vitro fertilization and embryo development of sheep oocytes     

In vitro maturation of oocytes: an option for fertility preservation in women

Although female cancer incidence may be on rise, antineoplastic regimens have become more successful. As a result, an increasing number of women with cancer survive to endure the long-term consequences of chemotherapy. One of the most important long-term consequences of cancers treatments in young female is premature ovarian failure and infertility. Because of the increasing survival rates, many of these young women are seeking methods to preserve their fertility. Currently, embryo/oocytes cryoporeservation obtained after ovarian stimulation appears to provide the best fertility preservation option. However, patients may not have sufficient time to undergo ovarian stimulation prior to chemotherapy and/or the hormones used in ovarian stimulation are contra-indicated for estrogen-dependant tumors. In vitro maturation of oocytes (IVM) has been suggested to avoid ovarian stimulation and time requirement in patients with cancer, and can be combined with ovarian tissue cryobanking. In this review, we will discuss the position of IVM in the strategy of fertility preservation in young women.     

In vitro maturation of baboon oocytes retrieved at the time of cesarean section

Objective: To investigate the feasibility of oocyte retrieval at the time of cesarean delivery and the potential of such oocytes to undergo nuclear maturation in vitro using a baboon model and an established culture system.

Design: Randomized, controlled animal study.

Setting: Research foundation and university research laboratory.

Animal(s): Mature pregnant baboons.

Intervention(s): In vitro culture of aspirated oocytes with or without epidermal growth factor (EGF).

Main Outcome Measure(s): Oocyte yield, germinal vesicle breakdown, polar body extrusion.

Result(s): A total of 246 oocytes were retrieved (mean, 35; range, 14–67). Eighty-seven oocytes (35%) underwent germinal vesicle breakdown and 72 oocytes (29%) extruded a polar body. A χ² analysis revealed no significant effect of EGF on outcome parameters. No effect of gestational age or maternal age on oocyte yield or development was observed.

Conclusion(s): A sizeable proportion of oocytes obtained from puerperal primates exhibited the capacity to undergo nuclear maturation in vitro.     

Endocrinology of in vitro maturation of oocytes

In-vitro maturation (IVM) of oocytes is an alternative to conventional in-vitro fertilization (IVF) treatment. Significant progress has been made to improve pregnancy and implantation rates from in-vitro matured oocytes. However oocyte maturation in vitro is profoundly affected by culture conditions. Most IVM protocols supplement gonadotropins--folicle stimulating hormone (FSH) and luteinizing hormone (LH) into a culture medium for oocyte maturation. The addition of these hormones, as well as some growth factors is based on their physiological role in oocyte maturation in vivo. However, it is possible, they not to play the same role in promoting oocyte maturation in vitro. The aim of this survey is to examine the hormones and growth factors, which participate in oocyte maturation in vivo and to summarize briefly the available information about the effect they have on the in vitro maturation. The researches on effects of these endocrine factors on oocyte maturation and subsequent fertilization, as well as on early embryonal development proceed.