Man receives transplant of his frozen prepubescent sperm-producing stem cells

A 26-year-old male cancer survivor received a transplant of his frozen prepubescent sperm-producing stem cells.

Researchers have transplanted, via an injection, his own sperm-forming stem cells, collected from testicular tissue when he was a child before undergoing chemotherapy for bone cancer. Chemotherapy is often linked to reduced fertility, and preserving testicular tissue could help prepubescent children, who do not produce sperm, to have the option to generate sperm in the future.

Professor Kyle Orwig, from the University of Pittsburgh Medical Centre, Pennsylvania, and lead researcher on the study, said: 'We're not expecting a miracle result… What we expect is that the transplant of stem cells will produce a small amount of sperm and that in order to achieve a pregnancy with his partner, he would need a follow-up assisted reproductive technology, like IVF.'

The patient, Jaiwen Hsu, was 11 when what was thought to be a routine sports injury turned out to be a tumour in his left femur. At that time, Hsu's parents were introduced to Professor Orwig and the tissue preservation study that he was conducting. Professor Orwig hoped that cryopreserving immature testicular tissues for young boys would preserve their future fertility. Even though those tissues weren't producing sperm yet, they do contain stem cells that have the potential to produce sperm.

The team's findings, published as a preprint in medRxiv, which has not yet been peer-reviewed, involved injecting sperm-producing stem cells into one of the man's testicles to restore sperm production. A year after the transplant, there was no visible change in the appearance of the man's testicular tissue, suggesting successful stem cell incorporation. While hormone levels also appeared normal, the patient was still not producing any sperm one year after transplantation.

Commenting on his participation in the clinical trial, Hsu added: 'The science behind it is so incredibly new that right now it's kind of a waiting game. It's kind of eagerly crossing our fingers and hoping for the best.'

Previously, the same research group produced a baby monkey using sperm isolated from grafted testicular tissue, leading to the first live primate birth using this technique (see BioNews 992).

Earlier this year, a man in Belgium received a similar transplant from frozen prepubescent testicular tissue. Here, the doctors re-introduced testicular tissue into the patient's testicles and scrotum in order to help produce his own sperm (see BioNews 1273).