Research program: "Preservation of fertility before gonadotoxic treatment: options for restoring fertility from cryopreserved prepubertal testicular tissue".
Chemo- and radiotherapeutic treatments have characterized devastating effects on prepubertal (1, 2) gonads. For those children, as spermatogenesis has not yet started, cryopreservation of immature testicular tissue (TTI) containing stem spermatogonia (SGS) is currently the only strategy for preserving their fertility prior to these potentially sterilizing treatments.
(3-5). Different approaches to obtain haploid germ cells from cryopreserved SGS are described in the literature: transplantation of purified SGS cell suspensions, testicular tissue autograft and in vitro maturation (MIV) to the haploid stage (6).
In our lab, we have developed a long-term culture system for the TTI MIV. We were able to demonstrate good preservation of seminiferous tubule integrity, Sertoli cell maturation and Leydig cell function (7). The optimization of the culture protocols to achieve an SGS differentiation and to obtain mature spermatozoa able to fertilize an oocyte are ongoing.
Since cancer treatments can damage the SGS, our laboratory is currently developing an artificial neoplastic cell free testis. A scaffold based on cell free TTI is under study. This will be used to support testicular cells previously isolated and selected from TTI. Then this replenished matrix could be autotransplanted to restore complete spermatogenesis in vivo.
Gonadotoxic treatments are also provided before bone marrow transplantation to treat benign hematologic diseases such as thalassemia major, aplastic anemia or sickle cell disease. Since in these cases TTI does not contain cancerous cells, fertility could be restored by TTI autograft. However, the efficiency of the transplantation technique evaluated in murine models (8, 9) needs to be improved to achieve a better survival of the SGS (10, 11). We are currently developing support matrices for the transplantation of fragments in order to promote angiogenesis and reduce the tissue and cell damage associated to oxidative stress before revascularization.
- Schrader, M., et al., The impact of chemotherapy on male fertility: a survey of the biologic basis and clinical aspects. Reprod Toxicol, 2001. 15(6): p. 611-7.
- Wallace, W.H., Oncofertility and preservation of reproductive capacity in children and young adults. Cancer, 2011. 117(10 Suppl): p. 2301-10.
- Ginsberg, J.P., et al., An experimental protocol for fertility preservation in prepubertal boys recently diagnosed with cancer: a report of acceptability and safety. Hum Reprod, 2010. 25(1): p. 37-41.
- Wyns, C., et al., Management of fertility preservation in prepubertal patients: 5 years' experience at the Catholic University of Louvain. Hum Reprod, 2011. 26(4): p. 737-47.
- Picton, H.M., et al., A European perspective on testicular tissue cryopreservation for fertility preservation in prepubertal and adolescent boys. Hum Reprod, 2015. 30(11): p. 2463-75.
- Wyns, C., et al., Options for fertility preservation in prepubertal boys. Hum Reprod Update, 2010. 16(3): p. 312-28.
- de Michele, F., et al., Preserved seminiferous tubule integrity with spermatogonial survival and induction of Sertoli and Leydig cell maturation after long-term organotypic culture of prepubertal human testicular tissue. Hum Reprod, 2016.
- Wyns, C., et al., Spermatogonial survival after cryopreservation and short-term orthotopic immature human cryptorchid testicular tissue grafting to immunodeficient mice. Hum Reprod, 2007. 22(6): p. 1603-11.
- Wyns, C., et al., Long-term spermatogonial survival in cryopreserved and xenografted immature human testicular tissue. Hum Reprod, 2008. 23(11): p. 2402-14.
- Poels, J., et al., Vitrification preserves proliferation capacity in human spermatogonia. Hum Reprod, 2013. 28(3): p. 578-89.
- Poels, J., et al., Transplantation of testicular tissue in alginate hydrogel loaded with VEGF nanoparticles improves spermatogonial recovery. J Control Release, 2016. 234: p. 79-89.