vitrification-ovarian-cortex-tissue-to-achieve-glassy-state

Vitrification of Ovarian Cortex Tissue to Achieve a Glassy State of Aggregation

Ovarian tissue cryopreservation (OTC) is an important option for fertility preservation. For patients whose gonadotoxic treatments cannot be postponed or ...

University Hospital of Bonn

Despite its clinical success rates, transplantation after ovarian tissue cryopreservation (OTC) remains a matter of concern. Certain cancer subtypes may lead to the transfer of malignant cells when transplantation of affected ovarian tissue is conducted. IVG and subsequent isolation of vital follicles obtained from frozen thawed ovarian tissue for further in vitro maturation (IVM) would expand current fertility protection techniques while reducing the risk of retransplanting malignant cells.

In vitro growth (IVG) of human ovarian follicles in frozen thawed ovarian cortex tissue culture supplemented with follicular fluid under hypoxic conditions.

The standard procedure most frequently used for ovarian tissue cryopreservation (OTC) is slow freezing, while vitrification has been proposed as promising alternative and has built an impressive catalog of success in fertility laboratories regarding cryopreservation of oocytes and embryos.

The effect of high-throughput vitrification of human ovarian cortex tissue on follicular viability: a promising alternative to conventional slow freezing?

What are the parameters of age, indications for ovarian tissue cryopreservation, storage characteristics and reasons for tissue disposal in a large cohort of individuals undertaking cryopreservation?

Cryostorage of human ovarian tissue: evaluating the storage and disposal pattern over a 22-year period in 2475 patients.

Vitrification of ovarian tissue is a promising alternative approach to the traditional slow freezing method. Few empirical investigations have been conducted to determine the angiogenic profiles of these two freezing methods. In this study we aimed to answer the question whether one of the cryopreservation methods should be preferred based on the secretion of angiogenic factors. Tissue culture with reduced oxygen (5%) was conducted for 48 h with samples of fresh, slow frozen/thawed and vitrified/rapid warmed ovarian cortex tissue from 20 patients. From each patient, tissue was used in all three treatment groups. Tissue culture supernatants were determined regarding cytokine expression profiles of angiogenin, angiopoietin-2, epidermal growth factor, basic fibroblast growth factor, heparin binding epidermal growth factor, hepatocyte growth factor, Leptin, Platelet-derived growth factor B, placental growth factor and vascular endothelial growth factor A via fluoroimmunoassay. Apoptotic changes were assessed by TUNEL staining of cryosections and supplemented by hematoxylin and eosin and proliferating cell nuclear antigen staining. Comparing the angiogenic expression profiles of vitrified/rapid warmed tissue with slow frozen/thawed tissue samples, no significant differences were observed. Detection of apoptotic DNA fragmentation via TUNEL indicated minor apoptotic profiles that were not significantly different comparing both cryopreservation methods. Vitrification of ovarian cortical tissue does not appear to impact negatively on the expression profile of angiogenic factors and may be regarded as an effective alternative approach to the traditional slow freezing method.

Comparison of angiogenic potential in vitrified vs. slow frozen human ovarian tissue.

Cryopreservation and reimplantation of human ovarian tissue restore the ovarian hormonal function and fertility due to the preservation of follicles. As the success depends on proper angiogenesis, different approaches aim to support this process. In mice, pretreatment of ovarian tissue with FSH shows increased follicular numbers probably due to the supported angiogenesis by an increased vascular endothelial factor (VEGF) expression. However, in human tissue it remains completely unclear, which effect the hormonal status of the patient has at the time point of reimplantation. Frozen-thawed human ovarian cortical tissue was cultured for 48 h with 0, 1 or 10 ng/mL recombinant human FSH. VEGF-A expression was assessed by ELISA and immunohistofluorescence (IHF) analysis. By IHF, HIF-1α and FSHR expression dependency on culture and FSH concentration was analyzed. Follicles at all stages expressed VEGF-A, which increases during folliculogenesis. Frozen-thawed human ovarian cortical tissue secreted a not statistically different amount of VEGF-A, when cultured in presence of 1 ng/mL FSH (17.5 mIU/mL). However, the presence of 10 ng/mL FSH (175 mIU/mL) significantly decreased VEGF-A expression and secretion. The high FSH concentration increased especially the VEGF-A expression of already growing follicles. The presence of pre-menopausal concentrations of FSH had no significant effect on VEGF-A expression, whereas the presence of elevated FSH levels decreased cortical VEGF-A expression. A hormonal pre-treatment of women with elevated FSH concentrations prior to reimplantation might be considered to support angiogenesis. Here, we show that VEGF-A expression by follicles is affected by FSH dependent on the concentration.

High FSH levels impair VEGF secretion of human, frozen-thawed ovarian cortical tissue in vitro.

Cryopreservation of ovarian tissue is one feasible option to preserve female fertility prior to cancer treatment. The slow freezing protocol represents the current standard approach, while vitrification has been suggested as a promising alternative. This paper reports the follow-up and first successful delivery after retransplantation of vitrified, rapid warmed ovarian tissue in Europe.

Article	Year
In vitro growth (IVG) of human ovarian follicles in frozen thawed ovarian cortex tissue culture supplemented with follicular fluid under hypoxic conditions. Archives of gynecology and obstetrics\| PubMed ID: 35871693	2022
The effect of high-throughput vitrification of human ovarian cortex tissue on follicular viability: a promising alternative to conventional slow freezing? Archives of gynecology and obstetrics\| PubMed ID: 36175682	2023
Cryostorage of human ovarian tissue: evaluating the storage and disposal pattern over a 22-year period in 2475 patients. Reproductive biomedicine online\| PubMed ID: 37400319	2023
Comparison of angiogenic potential in vitrified vs. slow frozen human ovarian tissue. Scientific reports\| PubMed ID: 37558708	2023
High FSH levels impair VEGF secretion of human, frozen-thawed ovarian cortical tissue in vitro. Scientific reports\| PubMed ID: 38332226	2024
First report on successful delivery after retransplantation of vitrified, rapid warmed ovarian tissue in Europe. Reproductive biomedicine online\| PubMed ID: 38744030	2024

Rebekka Einenkel

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