Fertility Preservation and Restoration Options for Pre-Pubertal Male Cancer Patients: Current Approaches

Fertility preservation for prepubertal male patients undergoing gonadotoxic therapies, potentially depleting spermatogonial cells, is an expanding necessity, yet most of the feasible options are still in the experimental phase. We present our experience and a summary of current and novel possibilities regarding the different strategies to protect or restore fertility in young male patients, before proceeding with chemotherapy or radiotherapy for malignances or other diseases. Adult oncological patients should always be counselled to cryopreserve the semen before starting treatment, however this approach is not suitable for prepubertal boys, who aren't capable to produce sperm yet. Fortunately, since the survival rate of pediatric cancer patients has skyrocketed in the last decade and it's over 84%, safeguarding their future fertility is becoming a major concern for reproductive medicine. Surgical and medical approaches to personalize treatment or protect the gonads could be a valid first step to take. Testicular tissue autologous grafting or xenografting, and spermatogonial stem cells (SSCs) transplantation, are the main experimental options available, but spermatogenesis in vitro is becoming an intriguing alternative. All of these methods feature both strong and weak prospects. There is also relevant controversy regarding the type of testicular material to preserve and the cryopreservation methods. Since transplanted cells are bound to survive based on SSCs number, many ways to enrich their population in cultures have been proposed, as well as different sites of injection inside the testis. Testicular tissue graft has been experimented on mice, rabbits, rhesus macaques and porcine, allowing the birth of live offspring after performing intracytoplasmic sperm injection (ICSI), however it has never been performed on human males yet. In vitro spermatogenesis remains a mirage, although many steps in the right direction have been performed. The manufacturing of 3D scaffolds and artificial spermatogenetic niche, providing support to stem cells in cultures, seems like the best way to further advance in this field.

The Safe Recipient of SSC Transplantation Prepared by Heat Shock With Busulfan Treatment in Mice

Safety is the chief consideration in recipient preparation of spermatogonial stem cell (SSC) transplantation in mammals, especially humans. In this study, we compared the safety of the SSC transplantation recipients that were prepared both by testes heat shock plus testes busulfan injection (heat shock+busulfan(t)) and by busulfan intraperitoneal injection (busulfan i.p.) only. Our results showed that heat shock+busulfan(t) treatment significantly (p < 0.05) reduced mortality in mice and did not produce bone marrow cell toxicity. Furthermore, heat shock+busulfan(t) treatment directly damaged SSCs and exhausted almost all of the germ cells in the testis; the exhaustion of these cells is considered a key factor in the successful preparation of the recipients. Therefore, we used heat shock+busulfan(t) treatment to prepare recipients of SSC transplantation. Two months after SSC transplantation, the number and length of donor SSC-derived colonies in the testis of recipient in heat shock+busulfan(t) group was closed to that in busulfan i.p. group. Therefore, compared with busulfan i.p. treatment, heat shock+busulfan(t) treatment improved the safety of recipient preparation without reducing the efficiency of SSC transplantation. Two GFP-positive offspring were produced from 1 of the 20 recipients that had mated with female mice 72 days after SSC transplantation. In conclusion, heat shock with busulfan treatment is a safe method to prepare the recipient of SSC transplantation in mice.

Alteration of spermatogenesis following spermatogonial stem cells transplantation in testicular torsion-detorsion mice

PURPOSE

Testicular ischemia is the main consequence of testicular torsion, in both clinical and experimental aspects. Preservation and auto-transplantation of spermatogonial stem cells (SSCs) could be a new treatment for infertility in testicular ischemia following testicular torsion.

METHODS

To apply the idea in this study, animals were randomly divided into four groups of control, sham, with torsion, and with torsion followed by transplantation (TT). Isolated SSCs from neonatal mice were cultured and identified by flow cytometry (C-KIT(-), INTEGRIN β1 (+)) and RT-PCR (Reverse transcription polymerase chain reaction) for specific spermatogonial cell markers (Oct4, Gfrα-1, Plzf, Vasa, Itgα 6 , and Itgβ 1 ). SSCs were transplanted upon a 2-h testicular torsion in the TT group. Cultured cells were transplanted into ischemia reperfusion testicle 2 weeks post-testicular torsion. Eight weeks after SSCs transplantation, the SSCs-transplanted testes and epididymis were removed for sperm analysis, weight and histopathological evaluation, and pre- and post-meiotic gene expression assessment by qRT-PCR.

RESULTS

Our findings indicated that all evaluated parameters (epididymal sperm profile, Johnsen score, Plzf, Gfrα-1, Scp-1, Tekt-1 expressions, and histopathological profile) were significantly decreased following testicular torsion (group 3) when compared to the control group (p ≤ 0.05). However, all abovementioned parameters showed a significant increase/improvement in torsion-transplantation group compared to torsion group. However, these parameters in the TT group were significantly lower in the sham and control groups (p ≤ 0.05).

CONCLUSION

SSCs transplantation could up-regulate the expression of pre- and post-meiotic genes in testicular ischemia, which resulted in improvement of both testicular function and structure after testicular torsion.