Cryopreservation of euploid blastocysts obtained after fertilization of in vitro matured ovarian tissue oocytes: a case report

Twenty-first century oocyte cryopreservation—in vitro maturation of immature oocytes from ovarian tissue cryopreservation in cancer patients: A systematic review

Objectives:

Our review aimed to consolidate the latest update on the application of in vitro maturation among immature oocyte harvest in combination with ovarian tissue cryopreservation known as ovarian tissue oocyte–in vitro maturation.

Methods:

A thorough search for relevant studies was conducted via PubMed, Google Scholar, EMBASE, and clinical.gov databases up to December 2020. The primary outcome was the oocyte maturation rate, which measured the number of immature oocytes (geminal vesicle stage) that progressed to mature oocytes (meiosis II stage) following in vitro maturation. The secondary outcomes were the fertilization rate following intracytoplasmic sperm injection/in vitro fertilization of these oocytes for the embryo cryopreservation cohort. Our review included pre-pubertal girls and women with cancer who underwent ovarian tissue oocyte–in vitro maturation as fertility preservation.

Results:

The primary search identified 207 studies. Twelve manuscripts were selected for inclusion in our review following duplication assessment, title and abstract screening, and full-text evaluation tailored to our inclusion criteria. All the population belonged to a cancer group and underwent concurrent ovarian tissue oocyte–in vitro maturation. A total of 5724 immature oocytes were obtained following ovarian tissue cryopreservation. Approximately 33.84% of the immature oocytes successfully matured via in vitro maturation, which were cryopreserved as oocytes or fertilized as embryos and subsequently stored for future use.

Conclusion:

Our review proposed the potential application of ovarian tissue oocyte–in vitro maturation in increasing the number of mature oocytes. The acceptable improvement in oocyte maturation rate following in vitro maturation indicates that improving oocyte outcomes is an excellent cost-effective strategy for fertility preservation among women with cancer.

Feasibility of in vitro maturation of oocytes collected from patients with malignant ovarian tumors undergoing fertility preservation

OBJECTIVE

In vitro maturation of oocytes collected from oophorectomy samples might be a promising approach in the field of oncofertility. In this study, we evaluate the feasibility of in vitro maturation of oocytes collected from oophorectomy samples in patients with ovarian tumors.

METHODS

This prospective observational study included 27 patients with malignant ovarian tumors. Patients underwent oophorectomy and ovarian tissue was examined for the presence of immature cumulus-oocyte complexes. These were matured in vitro for 48 hours. Mature oocytes were vitrified or used for fertilization. Serum anti-müllerian hormone (AMH) levels were analyzed in 11 patients and cancer antigen 125 (CA125) levels in 16 patients.

RESULTS

In this study, 99 cumulus-oocyte complexes were obtained from 17 patients (63%). The mean (SE) age of the patients was 33.47±1.86 years (range 16-44). A total of 14 patients had ovarian cancer (IA-IVB), one patient had ovarian cancer IC and endometrial cancer IA, one patient had endometrial cancer stage IA with metastasis into the ovary, and one patient had cervical cancer stage IIB with metastasis in the ovary. Oocytes were not obtained in 10 patients who had diminished ovarian reserve due to age (>38 years), chemotherapy, or previous surgical treatment. On average, 5.8 cumulus-oocyte complexes were obtained per patient. The maturation rate was 40.4% with an average of 2.8 metaphase II oocytes per patient. As a result of the study, 3 blastocysts in 3 patients and 22 oocytes in 9 patients were vitrified.

CONCLUSIONS

In vitro maturation of oocytes collected from oophorectomy samples in patients with malignant ovarian tumors may result in oocyte and blastocyst vitrification. However, it should be offered to patients before surgery and chemotherapy. This method might be most beneficial in patients younger than 38 years, with AMH serum levels >1 ng/mL and without a large tumor burden.

Improved maturation competence of ovarian tissue oocytes using a biphasic in vitro maturation system for patients with gynecological malignancy: a study on sibling oocytes

PURPOSE

To investigate the developmental competence of ovarian tissue oocytes from patients with gynecological tumors using a biphasic in vitro maturation system with capacitation (CAPA-IVM) in comparison with standard IVM.

METHODS

This sibling pilot study included 210 oocytes in 10 patients with gynecological malignancies. After ovariectomies, ovaries were cut into even halves and immature cumulus-oocyte complexes (COCs) were retrieved from the ovarian tissue. COCs were separately cultured in either a biphasic CAPA-IVM system for 53 h or in standard IVM for 48 h. After IVM, all COCs were denuded and mature oocytes were either vitrified (N=5) or used for ICSI (N=5). Embryos were cultured for 5-6 days and obtained blastocysts were vitrified.

RESULTS

Use of the CAPA-IVM system led to a higher meiotic maturation rate in ovarian tissue oocytes (OTO) compared to standard IVM (56 vs 35%, p=0.0045) and had a tendency to result in lower degeneration after IVM. Only the CAPA-IVM method supported blastocyst formation.

CONCLUSIONS

The biphasic in vitro maturation system improved the competence of OTO in comparison to the standard IVM method. The study suggests that fertility preservation programs could become more efficient using IVM after capacitation culture.