Recent advances in fertility preservation

Abstract

Background: Most cancer treatments like chemotherapy, radiotherapy or a combination of both are highly toxic to the gonads, putting girls and young women at risk of premature ovarian insufficiency and subsequent infertility. Non-oncological conditions may also require therapies that put women's reproductive potential at risk. Fertility preservation counseling should therefore be offered to all patients requiring gonadotoxic treatments, and to those who wish to postpone motherhood for social/personal reasons. Among the most effective fertility preservation options available today, oocyte and embryo cryopreservation, and ovarian tissue cryopreservation have emerged as the front-runners. Aim: This review focuses on the currently available and most widely accepted fertility preservation and restoration strategies, with a special focus on recent advances in ovarian tissue cryopreservation and transplantation. Conclusions: To manage cancer patients satisfactorily and offer proper counsel on the most appropriate option available to them, different parameters need to be taken into account, including pubertal status, partner status and urgency of treatment for the underlying pathology. When fertility preservation is carried out for non-oncological indications or personal reasons, oocyte cryopreservation by vitrification is clearly the highest-yield clinical strategy. Ovarian tissue cryopreservation followed by transplantation is rapidly gaining ground as a fertility preservation and restoration strategy, and will hopefully soon have its 'experimental' label removed to allow practitioners to move on to open clinical application. Techniques to improve grafted ovarian tissue life span and quality as well as to avoid transmission of malignant cells have been developed, showing promise as a way to expand this procedure.

A Japanese nationwide survey on the cryopreservation of embryos, oocytes and ovarian tissue for cancer patients

“…In the present study, breast cancer and hematological malignancies constitute the most common oncological indications for fertility preservation, which is in accordance with the existing studies . A recent report on fertility preservation for adult women in Spain showed that breast cancer and hematological malignancies accounted for 60.3% and 21.4% of indications for oocyte cryopreservation, respectively, while accounted for 53.9% and 29.6% for ovarian tissue cryopreservation.…”

“…In total, In the present study, breast cancer and hematological malignancies constitute the most common oncological indications for fertility preservation, which is in accordance with the existing studies. 14,15 A recent report on fertility preservation for adult women in Spain showed that breast cancer and hematological malignancies accounted for 60.3% and 21.4% of indications for oocyte cryopreservation, respectively, while accounted for 53.9% and 29.6% for ovarian tissue cryopreservation. Higher proportion of breast cancer patients (68.8%) in the present survey, compared to the Spanish study, may be explained by 10 times higher number of the cases of embryo and oocyte cryopreservation than that of ovarian tissue cryopreservation conducted in the present survey.…”

Translational research aiming to improve survival of ovarian tissue transplants using adipose tissue‐derived stem cells

“…8 One of our main goals is to resolve the problem of hypoxic conditions and their consequences in the early post-grafting period in order to enhance the efficacy of OT transplantation. 9 Xenografting models have explored treatments with growth factors (vascular endothelial growth factor), antioxidants (N-acetyl cysteine, erythropoietin, vitamin E and melatonin) and steroid hormones among others, but no significant clinically translatable improvement has so far been observed. 10 The idea of preparing the vascular bed prior to OT transplantation was also investigated in an experimental autologous cynomolgus monkey model.…”

The effect of delayed processing on ovarian tissue stored for fertility preservation

“…Isachenko et al also provided evidence that a 24 h cryopreservation delay at 4°C does not affect the proportion of morphologically normal follicles or follicle density in frozen-thawed ovarian cortical tissue (13). Conversely, another study described a decrease in the proportion of morphologically normal follicles induced by a 24 h freeze-delay prior to thawing and in vitro culture of human ovarian tissue (14), however, this study used vitrification, which relies on very high concentrations of cryoprotectants, while the present study employed slow freezing which is the currently accepted gold-standard method of ovarian tissue cryopreservation (25).…”