A monkey left infertile after undergoing chemotherapy as a juvenile has fathered a baby after scientists froze its testicular tissue before cancer treatment, then re-grew it after the animal reached adulthood to produce sperm.
It is the first time that the groundbreaking technique has been proven to work in primates and offers hope that childhood cancer patients can preserve their fertility.
Adult cancer patients have the option of banking their sperm, but for boys their reproductive tissue does not start producing sperm until puberty, so there is nothing to save.
As a result one in three childhood cancer survivors suffers infertility from harsh cancer treatment.
For the new research, scientists at the University of Pittsburgh cryopreserved the immature testicular tissue of five young rhesus monkeys who had not undergone puberty, before giving them chemotherapy.
The later thawed and transplanted the pieces of tissue under the skin of the same animals, and when they entered puberty, eight to 12 months later, the grafts were removed and sperm was found to be present.
The sperm was sent to Oregon Health and Science University who used it to fertilise 138 eggs, 41 per cent of which developed into early stage embryos and 11 were transferred into female monkeys.
Last April a female was born named ‘Grady’ - a portmanteau of ‘graft-derived’ and ‘baby’ - who has remained healthy.
“With Grady's birth, we were able to show proof-of-principle that we can cryopreserve prepubertal testicular tissue, and later use it to restore fertility as an adult,” said first author Dr Adetunji Fayomi, of Pittsburght’s School of Medicine.
“Previous research in non-human primates has demonstrated that sperm could be produced from transplants of frozen prepubertal testicular tissue, but the ability to produce a healthy live offspring - the gold standard of any reproductive technology - has not been achieved until now.”
In the UK, one in every 500 children under 15 develops a cancer and around About 1,600 children are diagnosed with cancer each year.
Girls are born with their eggs, which can be preserved, but boys do not produce sperm until a surge of testosterone at puberty activates stem cells and instructs the testicular tissue to fire up.
However in boys, chemotherapy, radiation or other medical treatments can kill these stem cells and cause permanent infertility.
The researchers said that proof that the technique works in primates is the final step before moving to trials in humans.
In the UK, one in every 500 children under 15 develops a cancer and around About 1,600 children are diagnosed with cancer each year.
Girls are born with their eggs, which can be preserved, but boys do not produce sperm until a surge of testosterone at puberty activates stem cells and instructs the testicular tissue to fire up.
However in boys, chemotherapy, radiation or other medical treatments can kill these stem cells and cause permanent infertility.
The researchers said that proof that the technique works in primates is the final step before moving to trials in humans.