Young boys with cancer who become infertile due to chemotherapy may be able to father children thanks to frozen testicular tissue.
A recent study in rats suggests that if testicular tissue was frozen before cancer treatment, it could be re-implanted later in life so that these pediatric cancer patients could one day have biological children through in vitro fertilization (IVF).
Researchers at the University of Pennsylvania were able to reintroduce testicular cells frozen for 23 years into infertile mice, which were then shown to produce healthy sperm.
The success of this study in mice could provide hope for men facing infertility as a side effect of childhood cancer treatments.
The mice in the study had been treated with a drug that killed their sperm-forming cells. Later, when the testes of the mice, implanted with the conserved stem cells, were examined, the 23-year-old stem cells had survived and developed into groups of sperm-producing cells.
The groups of cells from the implants made mature sperm, but only about a third as many as those derived from implants of fresh or freshly frozen cells.
However, even the low sperm count proves to be encouraging for scientists if it works in humans.
“You really only need one viable sperm cell to be successful,” Eoin Whelan, one of the authors of the study, told New Scientist.
Chemotherapy for the treatment of cancer in young boys can kill stem cells in the testicles that form sperm. While adults may have their sperm samples frozen before treatment, children who are not yet in puberty may resort to this option.
Some clinics have removed and frozen small samples of children’s immature testicular tissue in the hope that if re-implanted when they are adults, it will mature and begin to form sperm.
It is unclear whether the results will translate into humans, as the researchers froze isolated testicular stem cells while fertility clinics freeze whole tissue samples.
The researchers also took the cells from adult rats, while clinics take tissues from children who have not yet gone through puberty.
Previous research on monkeys had shown that it was possible to use cells frozen for several months, but the latest study suggests that long-term freezing is also viable.
In 2019, the first monkey was born using the ‘frozen testicle technique’ in an important breakthrough to get approved experiments on humans.
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