By Holly Giles
Grady, the rhesus macaque in the Oregon National Primate Research Center, is being watched very carefully as he nears his first birthday this week. Grady is the first primate to be born and reach the age of one who was developed using tissues from frozen testes.
Testicular tissue was harvested from Grady’s father when he was too young to produce sperm. The tissue was frozen until just before puberty where it was sewed under the skin of the back and the scrotum. A year later it was observed that the tissues were producing testosterone at the same levels of the surrounding tissues and were making sperm. This sperm was then removed and used for in vitro fertilisation to produce offspring, Grady.
If he continues to grow up without any issues, then it is safe to assume this method will soon be ready for testing on humans. Lead study author Kyle Orwig confirms this when he says, “I think with that paper, ethics committees throughout the world will be granting clinical studies”.
The success of generating sperm from grafted tissue has significant implications for patients who have been treated for cancer prior to puberty. Currently, it is only possible for them to have children by freezing sperm before treatment so for patients who are too young to produce sperm this is not possible. However, this new method means it may be possible for them to remove tissue samples prior to treatment and then graft them on at the age of puberty.
The only concern with this treatment, as explained by Ellen Goossens, a reproductive biologist at the Vrije Universiteit Brussel (VUB), is the risk of reintroducing tumours is the grafts are not cancer free. This means new methods are needed to ensure the tissue is free of cancer prior to inserting it. The investigation also has wide implications for the farming industry where teams are working to apply similar methods on livestock where sperm-producing stem cells could be transferred from elite animals to non-elite individuals. This could speed up breeding efforts to produce more high value offspring.
However exciting the next steps of this investigation are, it is important to recognise the implications of this step. “It’s a huge step that this can be performed in primates” states Goossens, and she is right. This week it has been proved an organism with an ancestral lineage similar to humans can reach the age of one using tissue from frozen testes prior to puberty. This ground-breaking find is a huge step for the field of developmental biology.