Application of Decellularized Tissue Scaffolds in Ovarian Tissue Transplantation

Oocyte cryopreservation with in vitro maturation for fertility preservation in girls at risk for ovarian insufficiency

PURPOSE

To assess the feasibility and outcomes of oocyte cryopreservation with in vitro maturation (IVM) in post-pubertal girls undergoing fertility preservation (FP) for primary ovarian insufficiency (POI) risk.

METHODS

Ovarian stimulation was performed with an antagonist protocol or progesterone priming. Ultrasound monitoring was performed transabdominally. Oocytes were retrieved transvaginally under IV sedation. Immature oocytes were subjected to IVM for up to 36 h. All MII oocytes were vitrified. The main outcome measure was the total number of mature oocytes cryopreserved. The secondary outcome was the increase in the mature oocyte yield after IVM.

RESULTS

Indications for FP included mosaic Turner syndrome (mTS; n = 10), malignancy (n = 3), and POI risk (n = 2). The mean ± SD age, antral follicle count (AFC), and AMH levels were 14.2 ± 1.4 years, 8 ± 5.2 and 1.3 ± 1.3 ng/mL. In girls with mTS, the ovarian reserve was low for age (AFC 7.4 ± 4.7 and AMH 1.4 ± 1.6 ng/mL). Oocyte cryopreservation was possible in all girls with a range of 1-27 mature oocytes obtained, even in those who were previously exposed to chemotherapy or with low ovarian reserve, and no surgical complications were encountered. After IVM, the median mature oocyte yield increased significantly from 7.5 to 10.5 (p = 0.001).

CONCLUSIONS

Oocyte cryopreservation appears to be feasible and safe in girls as young as 12 years of age at risk for POI The utility of IVM increases the yield of cryopreserved mature oocytes. Prior exposure to chemotherapy or low ovarian reserve should not be an automatic reason to exclude these girls from FP consideration.

Making a good egg: human oocyte health, aging, and in vitro development

Mammalian eggs (oocytes) are formed during fetal life and establish associations with somatic cells to form primordial follicles that create a store of germ cells (the primordial pool). The size of this pool is influenced by key events during the formation of germ cells and by factors that influence the subsequent activation of follicle growth. These regulatory pathways must ensure that the reserve of oocytes within primordial follicles in humans lasts for up to 50 years, yet only approximately 0.1% will ever be ovulated with the rest undergoing degeneration. This review outlines the mechanisms and regulatory pathways that govern the processes of oocyte and follicle formation and later growth, within the ovarian stroma, through to ovulation with particular reference to human oocytes/follicles. In addition, the effects of aging on female reproductive capacity through changes in oocyte number and quality are emphasized, with both the cellular mechanisms and clinical implications discussed. Finally, the details of current developments in culture systems that support all stages of follicle growth to generate mature oocytes in vitro and emerging prospects for making new oocytes from stem cells are outlined.

Decellularized bovine ovarian niche restored the function of cumulus and endothelial cells

Objective:

Recently, the decellularization technique is introduced as one of the tissue engineering procedures for the treatment of various deficiencies. Here, we aimed to assess the dynamic activity of CCs and HUVECs within decellularized bovine ovarian tissue transplanted subcutaneously in rats. Ovarian tissue was decellularized using a cocktail consisting of different chemicals, and the efficiency of decellularization was assessed using hematoxylin-eosin and DAPI staining. The cell survival was evaluated using an LDH leakage assay. Thereafter, decellularized samples were recellularized using HUVECs and CCs, encapsulated inside alginate (1.2%)-gelatin, (1%) hydrogel, and transplanted subcutaneously to rats. The existence of CD31- and estrogen-positive cells was assessed using immunohistochemistry staining.

Results:

Bright-field imaging and DAPI staining revealed the lack of nuclei with naive matrix structure in ovarian tissue subjected to decellularization protocol. SEM imaging revealed a normal matrix in decellularized ovaries. LDH assay showed a lack of cytotoxicity for CCs after 7-days compared to the control group. Immunohistochemistry staining showed both CD31- and estrogen-positive cells in CCs + HUVECs compared to the CCs group. CD31 cells appeared with flattened morphology aligned with matrix fibers. The existence of estrogen and CD31 positive cells showed the efficiency of decellularized ovarian tissue to restore cellular function and activity.

Comparison of open and a novel closed vitrification system with slow freezing for human ovarian tissue cryopreservation

PURPOSE

To investigate the differences concerning post-thawing/warming follicle survival, DNA damage and apoptosis in human ovarian tissues cryopreserved by slow freezing, open, or closed vitrification methods.

METHODS

A total of 50 pieces of 5 × 5 × 1 mm ovarian cortical pieces were harvested (5 donor ovaries; mean age 31 ± 6.62 years). From each donor, one cortical piece was used as baseline; the remaining were randomly assigned to slow freezing (SF), vitrification using open device (VF-open), or closed device (VF-closed) groups. After 8-10 weeks of cryostorage, tissues were evaluated 4 h after thawing/warming. Histological analysis was evaluated for follicle survival (primordial and primary follicle densities) by H&E staining. The percentages of primordial and primary follicles with DNA double-strand breaks (γH2AX) and apoptotic cell death pathway activation (AC3) were immunohistochemically assessed. Data were analysed using one-way ANOVA and LSD post hoc comparison.

RESULTS

Compared to the baseline, primordial follicle (pdf) densities significantly declined in all cryopreserved groups (SF, VF-open, and VF-closed, P < 0.05). However, the total and non-apoptotic pdf densities were similar among SF, VF-open, and VF-closed. SF and VF with either open or closed devices did not increase the percentages of primordial or primary follicles with DNA double-strand breaks (DSBs) or apoptosis compared to the baseline or among the freezing methods in the present study.

CONCLUSION

Based on the intact primordial follicle survival, DNA damage, and apoptosis rates after thawing/warming, SF vs VF with either open or newly developed closed devices appear to be comparable.

Fertility preservation in gynecologic cancers

An increasing number of women in modern societies are delaying childbearing beyond the age of 35, and gynecologic cancers affect a significant proportion of reproductive age women who wish to preserve fertility for a future chance of childbearing. As a result, providing treatment options for fertility preservation in women with gynecologic cancer has become a crucial component of cancer survivorship care. In this review article, we discussed the current knowledge on fertility-sparing surgical approaches, as well as assisted reproductive technologies that can be utilized to preserve reproductive potential in women with cervical, endometrial, and ovarian cancer. A brief section on fertility preservation in pediatric gynecologic malignancies is also provided.