Oocyte and embryo cryopreservation before gonadotoxic treatments: Principles of safe ovarian stimulation, a systematic review

In vivo and in vitro sperm production: an overview of the challenges and advances in male fertility restoration

Male infertility can be caused by genetic anomalies, endocrine disorders, inflammation, and exposure to toxic chemicals or gonadotoxic treatments. Therefore, several recent studies have concentrated on the preservation and restoration of fertility to enhance the quality of life for affected individuals. It is currently recommended to biobank the tissue extracted from testicular biopsies to provide a later source of spermatogonial stem cells (SSCs). Another successful approach has been the in vitro production of haploid male germ cells. The capacity of SSCs to transform into sperm, as in testicular tissue transplantation, SSC therapy, and in vitro or ex vivo spermatogenesis, makes them ideal candidates for in vivo fertility restoration. The transplantation of SSCs or testicular tissue to regenerate spermatogenesis and create embryos has been achieved in nonhuman mammal species. Although the outcomes of human trials have yet to be released, this method may soon be approved for clinical use in humans. Furthermore, regenerative medicine techniques that develop tissue or cells on organic or synthetic scaffolds enriched with bioactive molecules have also gained traction. All of these methods are now in different stages of experimentation and clinical trials. However, thanks to rigorous studies on the safety and effectiveness of SSC-based reproductive treatments, some of these techniques may be clinically available in upcoming decades.

Investigating Ovulation Induction Outcomes in Patients with Decreased Ovarian Reserve Treated with Double Stimulation during The Follicular and Luteal Phases Compared to The Conventional Antagonist Cycle: A Randomized Clinical Trial

BACKGROUND

It is difficult to obtain healthy oocytes in poor ovarian responders with conventional treatment methods. Thus, the need to investigate new methods is essential. This study aims to investigate ovulation induction outcomes in patients with decreased ovarian reserve (DOR) in two groups treated with double stimulation (DuoStim) during the follicular and luteal phases in comparison with the antagonist cycle.

MATERIALS AND METHODS

This was a randomised clinical trial that enrolled the patients with reduced ovarian reserve. The patients referred for in vitro fertilization (IVF) at Molud Infertility Clinic, Ali Ebn Abitalib (AS) Hospital, Zahedan, Iran from 2020 to 2021. Participants were randomly divided into two groups, those who underwent treatment with DuoStim during the follicular and luteal phase (case group) and those who received the conventional antagonist cycle (control group).

RESULTS

The mean number of metaphase II (MII) eggs was 7.7 ± 3.1 in the case group and 6.1 ± 3.9 in the control group (P=0.063). The mean total number of retrieved eggs in the case group was 9.2 ± 3.7 and in the control group, it was 6.9 ± 4.4 (P=0.023). The mean number of embryos obtained in the case group was 6.5 ± 3.9; in the control group, it was 4.7 ± 2.8 (P=0.016).

CONCLUSION

The DuoStim method can effectively play a role in increasing the total number of retrieved eggs and embryos (registration number: IRCT20120817010617N8).

The Usage of Cryopreserved Reproductive Material in Cancer Patients Undergoing Fertility Preservation Procedures

BACKGROUND

Many cancer treatment methods can affect fertility by damaging the reproductive organs and glands that control fertility. Changes can be temporary or permanent. In order to preserve the fertility of cancer patients and protect the genital organs against gonadotoxicity, methods of fertility preservation are increasingly used. Considering that some patients ultimately decide not to use cryopreserved reproductive material, this review analysed the percentage of post-cancer patients using cryopreserved reproductive material, collected before treatment as part of fertility preservation.

METHODS

A systematic search of studies was carried out in accordance with the Cochrane Collaboration guidelines, based on a previously prepared research protocol. The search was conducted in Medline (via PubMed), Embase (via OVID), and the Cochrane Library. In addition, a manual search was performed for recommendations/clinical practice guidelines regarding fertility preservation in cancer patients.

RESULTS

Twenty-six studies met the inclusion criteria. The studies included in the review discussed the results of cryopreservation of oocytes, embryos, ovarian tissue, and semen. In 10 studies, the usage rate of cryopreserved semen ranged from 2.6% to 21.5%. In the case of cryopreserved female reproductive material, the return/usage rate ranged from 3.1% to 8.7% for oocytes, approx. 9% to 22.4% for embryos, and 6.9% to 30.3% for ovarian tissue. In studies analysing patients' decisions about unused reproductive material, continuation of material storage was most often indicated. Recovering fertility or death of the patient were the main reasons for rejecting cryopreserved semen in the case of men.

CONCLUSION

Fertility preservation before gonadotoxic treatment is widely recommended and increasingly used in cancer patients. The usage rate is an important indicator for monitoring the efficacy of these methods. In all of the methods described in the literature, this indicator did not exceed 31%. It is necessary to create legal and organizational solutions regulating material collection and storage and to create clear paths for its usage in the future, including by other recipients.

Oocyte and embryo cryopreservation in assisted reproductive technology: past achievements and current challenges

Cryopreservation has revolutionized the treatment of infertility and fertility preservation. This review summarizes the milestones that paved the way to the current routinary clinical implementation of this game-changing practice in assisted reproductive technology. Still, evidence to support "the best practice" in cryopreservation is controversial and several protocol adaptations exist that were described and compared here, such as cumulus-intact vs. cumulus-free oocyte cryopreservation, artificial collapse, assisted hatching, closed vs. open carriers, and others. A last matter of concern is whether cryostorage duration may impact oocyte/embryo competence, but the current body of evidence in this regard is reassuring. From social and clinical perspectives, oocyte and embryo cryopreservation has evolved from an afterthought when assisted reproduction was intended for immediate pregnancy with supernumerary embryos of secondary interest to its current purpose, which primarily is to preserve fertility long-term and more comprehensively allow for family planning. However, the initial consenting process, which still is geared to short-term fertility care, may no longer be relevant when the individuals that initially preserved the tissues have completed their reproductive journey. A more encompassing counseling model is required to address changing patient values over time.

Reproductive and Obstetric Outcomes after Fertility-Sparing Treatments for Cervical Cancer: Current Approach and Future Directions

Cervical cancer is one of the leading causes of cancer-related death in women of reproductive age. The established fertility-sparing approaches for the management of early-stage cervical cancer for women who plan pregnancy are associated with a decline in fecundity and an increased risk of pregnancy complications. This article aims to offer an overview of fertility-sparing approaches and the management of potential subfertility and pregnancy complications after these treatments. An extensive search for the available data about infertility and cervical cancer, fertility-sparing techniques in patients with cervical cancer, fertility treatment, obstetrical complications, and pregnancy outcomes in cervical cancer patients was completed. Fertility-preserving procedures such as loop electrosurgical excision procedure (LEEP), cold-knife conization, and trachelectomy in women diagnosed with cervical cancer can be considered as safe and effective treatments that preserve reproductive potential. Current fertility-preserving procedures, based on the balance of the oncological characteristics of patients as well as their desire for reproduction, allow one to obtain acceptable reproductive and obstetric outcomes in women treated for cervical cancer. Nevertheless, careful monitoring of pregnancies obtained after fertility-preserving procedures is recommended, since this cohort of patients should be considered at higher risk compared with a healthy population.

Fertility-sparing options for cancer patients

Fertility preservation is becoming an integral part of cancer care among women of reproductive age. Despite advances in the treatment of pelvic malignancies, all the currently available treatment approaches, including radiotherapy, chemotherapy, and surgery, place women at high risk for future fertility impairment. With improved long-term survival rates associated with cancer, expanding the reproductive options available is of high priority. Several fertility preservation options are available today for women with gynecologic and non-gynecologic malignancies. Depending on the underlying oncological entity, these can include the following procedures whether alone or in combination: oocyte cryopreservation, embryo cryopreservation, ovarian tissue cryopreservation, ovarian transposition, and trachelectomy. The purpose of this review is to provide the most up-to-date information on the aforementioned fertility-preserving approaches and highlight the current challenges, drawbacks, and areas of research where more data are still very necessary to optimize outcomes in young female oncological patients desiring pregnancy in the future.

Application of Nanoparticles and Melatonin for Cryopreservation of Gametes and Embryos

Cryopreservation of gametes and embryos, a technique widely applied in human infertility clinics and to preserve desirable genetic traits of livestock, has been developed over 30 years as a component of the artificial insemination process. A number of researchers have conducted studies to reduce cell toxicity during cryopreservation using adjuvants leading to higher gamete and embryo survival rates. Melatonin and Nanoparticles are novel cryoprotectants and recent studies have investigated their properties such as regulating oxidative stresses, lipid peroxidation, and DNA fragmentation in order to protect gametes and embryos during vitrification. This review presented the current status of cryoprotectants and highlights the novel biomaterials such as melatonin and nanoparticles that may improve the survivability of gametes and embryos during this process.