A research study focused on fertility preservation and restoration is giving boys who have a high risk of becoming sterile the option to bank a small piece of testicular tissue prior to treatment.
“The average survival rates for childhood cancer are around 80%, but a side effect of some treatments can be permanent sterility,” said Thomas W. McLean, MD, a pediatric cancer specialist, who co-leads the experimental biological bank with Hooman Sadri-Ardekani, MD, PhD, a male infertility specialist at the Medical Center’s Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina. “Preserving or restoring the ability of our patients to one day have children is an important aspect of their treatment.”
From the stored tissue, researchers can extract spermatogonial stem cells (SSCs), which are responsible for the continuous production of sperm throughout adult life. Physicians and scientists hope that when the boys reach adulthood, the cells can be transplanted back into their testicles through a simple injection and they will be able to produce sperm.
“SSC transplantation has not yet been attempted in humans, but has been performed successfully in several species of animals, including monkeys,” said Sadri-Ardekani, who developed the first laboratory protocol to isolate and grow human SSCs from small testicular biopsies.
McLean said a treatment to preserve fertility in boys who are not sexually mature is especially needed because no options currently exist for them. Older boys and men, on the other hand, can bank sperm for future use and women and girls can bank eggs or ovarian tissue.
SSCs are particularly sensitive to radiation and chemotherapy. Examples of cancers that involve these treatments that have a high risk of infertility are certain leukemias, Hodgkin’s disease, brain tumors, and bone cancer.
For the current research study, participants have a small piece of testicular tissue harvested under general anesthesia while they are undergoing another procedure associated with their care, such as putting a catheter in the chest to deliver chemotherapy drugs.
“Because the testicular biopsies do not contain enough SSCs to fully repopulate the testis, we developed a protocol to multiply the original SSCs by sufficient numbers for re-implantation,” said Sadri-Ardekani.
The experimental testicular tissue banking was designed under Good Tissue Processing (GTP) practices and is registered by the U.S. Food and Drug Administration and the ICCBBA, an international standards organization, for possible future cell therapy. The tissue is frozen free of charge until patients are at least 18 years old. At that time, it is expected that they will have the opportunity to enter into a separate research study to consider implantation.
“We are pleased that Wake Forest Baptist can offer this option to our young patients at Brenner Children’s Hospital,” said McLean. “Our hope is that by the time they are adults, these stored cells can be used to restore their fertility.”