Scientists have moved a step closer to being able to preserve fertility
in young boys who undergo chemotherapy and radiation treatments for cancer. The
new research, published in Fertility and Sterility, the journal of the American
Society for Reproductive Medicine, addresses the safety of an option scientists
are developing for boys who aren’t sexually mature and cannot bank sperm.
Scientists aim to freeze a sample of the boys’ testicular tissue so that when
they reach adulthood, spermatogonial stem cells (SSCs) found in the tissue can
be reproduced and transplanted back into the patients. These cells are
responsible for sperm production throughout adulthood.
“Our study addressed
an important safety issue – whether cancer cells that might be present in testicular
tissue samples can survive the process to replicate the sperm-producing stem cells,”
said lead author Hooman Sadri-Ardekani, M.D., Ph.D., an instructor in urology
and regenerative medicine at Wake Forest Baptist Medical Center.
“This is an important
consideration because of the potential to re-introduce cancer into the
patient,” he said. “The research, which involved one of the most common childhood
cancers, shows that the cancer cells were eliminated. Based on these findings, we
recommend that all boys with cancer be offered the option of storing testicular
tissue for possible future clinical use.”
Sadri-Ardekani performed the work
with researchers at the University of Amsterdam and Avicenna Research Institute
in Tehran, Iran, before joining Wake Forest Baptist.
Cancers that can have a high risk of infertility, depending on the treatment,
are certain leukemias, Hodgkin’s disease, brain tumors and bone cancer. Because
of the high survival rates of childhood cancer – close to 80 percent – more
cancer patients than ever are reaching adulthood and many face fertility
problems.
The current research involved acute lymphoblastic leukemia (ALL) cells, a
common type of childhood cancer. Previous research had shown that up to 30
percent of boys with ALL had cancer cells in their testicular tissue.
Several earlier studies have attempted to eliminate cancer cells from biopsy
tissue, but they showed contradictory results. The approach of Sadri-Ardekani
and colleagues was to investigate whether cancer cells would survive the laboratory
protocol they had developed to reproduce SSCs from a small tissue biopsy. This
process multiplies the original SSCs by 18,000-fold so there are enough cells to
transplant back into the patient when he reaches adulthood.
For the research, ALL
cells were taken from three patients’ bone marrow. The team then put the ALL
cells alone, and ALL cells combined with testicular cells, through the cell-reproduction
process.
Even when ALL cells
made up 40 percent of the cell mixture being cultured, they were entirely eliminated
in 26 days of culture.
“This pilot study
showed that the culture system not only allowed for efficient propagation of
sperm stem cells, but also eliminated ALL cells,” said Sadri-Ardekani.
SSC transplantation has not yet been attempted in humans, but has been performed
successfully in several species of animals, including monkeys, said Sadri-Ardekani.
He noted that before physicians and scientists begin offering SSC
transplantation in patients, additional research will be needed, including
whether other types of leukemia cells will also be eliminated in the
cell-propagation process.
Co-researchers were Christa Homberg, M.Sc., and Ellen van der Schoot, M.D.,
Ph.D., Sanquin Research, Amsterdam, the Netherlands; and Toni M. M. van Capel,
B.Sc., Henk van den Berg, M.D., Ph.D., Fulco van der Veen, M.D., Ph.D., Ans
M.M. van Pelt, Ph.D., and Sjoerd Repping, Ph.D., University of Amsterdam.
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Media Relations
Karen Richardson: krchrdsn@wakehealth.edu, 336-716-4453