New technology for freezing testicular tissue

A potential way to preserve testicular stem cells so that boys might undergo cancer treatment without risking their fertility was announced by the Washington State University.

Adult men can have their sperm frozen before undergoing radiation or chemotherapy. Boys who have not been through puberty can only have testicular tissue removed and frozen.

The researchers claim they are well on their way to developing technology that could culture the cells and transplant them back in the testes, where they might produce sperm after puberty.

Working with prepubescent mouse pups, the researchers put a fluorescent tag on a gene specific to stem cells in order to watch the process of a stem cell differentiating to create the progenitors that eventually become sperm.

The researchers changed the standard culture conditions by lowering the oxygen in the culture and they improved the percentage of stem cells capable of making normal sperm when transplanted back into testes (in the animal model).

Where before only 5 percent of the cells remained viable after six months, with this technique 40 percent were viable.

It remains to be seen if the cultured stem cells undergo changes to their epigenome, which determines if genes are turned on and off. The team will also investigate whether the technique will work with human tissues.

In my opinion, the research is very interesting as it might open new ways for testicular tissue transplantation and help save the future fertility of boys suffering from cancer. However, it is important to know that for the time being the Human Fertilisation and Embryology Authority clearly states that “Testicular tissue freezing is still highly experimental” and ASCO (American Society of Clinical Oncology) in the Recommendation on Fertility Preservation in Cancer Patients states that “Testicular tissue or spermatogonial cryopreservation and transplantation or testis xenografting have not yet been tested successfully in humans. Of note, such approaches are also the only methods of fertility preservation potentially available to prepubertal boys.”

https://britishfertilitysociety.org.uk/downloads/ms_3238.pdf

http://ascopubs.org/doi/full/10.1200/jop.2006.2.3.143

https://www.hindawi.com/journals/ogi/2010/160386/