Restoring the fertility of young boys made sterile by childhood cancer treatment has come a step closer. Scientists claim they've successfully multipled sperm stem cells collected from young boys' testes in the laboratory. They believe they could grow enough cells to repopulate adult cancer survivors' testes where they would mature into sperm.
There are currently no effective techniques for preserving the fertility of pre-pubescent boys undergoing cancer treatment since they don't have mature sperm to bank. But one in 250 young adults is a cancer survivor and survival rates for childhood cancers is now 80 percent.
Lead researcher Dr Hooman Sadri-Ardekani, from the University of Amsterdam, said: 'According to several animal studies, we could use testicular tissue from these boys before starting intensive chemotherapy or radiotherapy and cryopreserve (freeze) the tissue'.
In their research, the team isolated testicular tissue containing sperm stem cells from two boys aged six and eight who had Hodgkin's lymphoma. After two to three weeks, the multiplying cells formed stem cell lines - families of stem cells. The scientists worked out the cells had to be grown for 80 days in the laboratory, and the number of cells increased by 1,300 times, to create enough immature sperm to give a good chance of restoring fertility.
Dr Sadri-Ardekani is confident this system will work, although there are concerns over the safety of the procedure. Some studies have shown when stem cells are grown for long periods in culture medium in the laboratory, they can develop genetic faults.
Although he admitted that the techniques were still 'experimental', he said: 'We really should offer at least sperm stem cell cryopreservation (freezing) to these boys to give them this opportunity in the future'.
Dr. Allan Pacey, Senior Lecturer in Andrology at the University of Sheffield said: ' If testicular stem cells could be removed, stored and replaced safely after cancer treatment then there is hope that the individual could produce sperm quite naturally without the need for IVF, but I would urge caution in interpreting the results presented to date'.
'Before such techniques enter clinical practice we need to make absolutely sure that they are safe and that any sperm produced post-transplant are genetically 'normal'', he said. 'Also, we need to be sure that metastatic cancer cells are not replaced along with the stem cells, as inadvertently re-introducing the disease into the patient would be catastrophic'. The research was presented at the American Society for Reproductive Medicine's annual conference.