In a world first, doctors in Belgium have transplanted testicular tissue into an adult man after it was frozen prior to chemotherapy 16 years ago when he was a child.
In the procedure, doctors at the Free University of Brussels and Brussels IVF, the centre for reproductive medicine of UZ Brussel, reintroduced tissue fragments into the man's testicles and scrotum in a technique that is designed to spark the production of sperm cells. Although prepubescent boys do not produce sperm, the preserved tissue contains the stem cells needed for sperm production after puberty.
'This is an important step in further scientific research to preserve the fertility of children with cancer,' said Dr Veerle Vloeberghs from Brussels IVF. 'While the procedure is specifically designed to restore fertility, we cannot at this time guarantee that it will be successful or that patients can go on to have children... they now have options that they did not have until recently.'
After the transplant, the team will monitor the patient for a year, through periodic hormone, blood, ultrasound and semen sample analysis. The tissue fragments will be retrieved one year after transplantation and examined to check whether they produce sperm cells. The researchers will also remove a tissue sample in a separate part of the testis, to determine whether sperm cell production was triggered there.
'This is such an important step forward for the field of fertility preservation in boys facing treatments that can affect future fertility. Testicular tissue cryopreservation has been offered to boys before they receive chemotherapy for many years and we know that more than 3000 boys worldwide have had testicular tissue stored,' Professor Rod Mitchell, from the Centre for Reproductive Health at the University of Edinburgh, who was not involved in the study, told BioNews.
The researchers noted that as the reintroduced tissue fragments are not connected directly to the sperm duct, they do not expect sperm cells to naturally occur in the semen samples. Fertility treatment may be needed for a successful pregnancy to occur, however this procedure provides the opportunity for the production of a patient's own sperm, in a group whereby there were no options previously.
'While we don't know the outcome of this procedure yet, we very much look forward to finding out if this is successful in producing sperm that can be used to help them have children. Clinical trials to re-transplant testicular tissue have also opened in the UK and we are looking to recruit patients who have had testicular tissue frozen during childhood prior to chemotherapy. We hope that these studies will provide a real possibility for young boys facing future infertility to father children of their own,' Professor Mitchell said.
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