Frozen testicular tissue can still make sperm after 20 years, study reveals

Breakthrough study finds frozen testicular tissue can still make sperm 23 years on, Tom Ambrose reports

The latest study involved sperm stem cells that had been extracted from rodents

Cryogenically frozen testicle cells could still be used 20 years after the sample was taken, according to a new study.

It means the cells could be reimplanted into infertile men two decades on from when the tissue was originally harvested, scientists have found.

It comes after researchers at the University of Pennsylvania were able to generate healthy sperm in infertile mice in a study published in the PLOS Biology journal.

Dr Eoin Whelan, a stem cell expert and lead researcher, said: “Our study showed that rat spermatogonial stem cells can be successfully frozen for over 20 years, transplanted into an infertile recipient animal and regenerate the ability to produce sperm, albeit at a reduced rate.

“This could provide a method to recover the loss of fertility in prepubertal boys treated for cancer.”

While adults in the UK and US are able to pay to have their sperm frozen, young boys who cannot produce mature sperm are unable to preserve functioning sperm for later life.

However, they do produce sperm stem cells which can be frozen before being reactivated after puberty.

The latest study, which involved stem cells from rodents, were frozen over three different periods of time - 23 years, up to four months and one day.

While it remains unclear if the results will translate to humans, it does offer some hope for men who face infertility as a side effect of childhood cancer treatments.

However, scientists working on this study froze isolated testicle stem cells, while fertility clinics are freezing whole tissue samples.

Previous research on monkeys had demonstrated that it was possible to use cells frozen after several months but the latest study suggests long-term freezing is also now a viable option for humans.

“You really only need one viable sperm to succeed,” Dr Whelan told the New Scientist.