According to a story released by the Canadian Press Toronto recent research shows there may be hope of preserving fertility in young males who undergo chemo treatments for cancer to still be able to later father children. Chemotherapy and radiation destroy stem cells in the testes that upon puberty allow for the creation of sperm. When young boys undergo chemo or radiation they almost always become infertile.
Researchers have been doing research that involved macaque monkeys where small testicular samples are frozen and then re-implanted after chemotherapy to begin the production of sperm. In the monkeys this was very successful.
Because this research was so successful in the monkeys, researchers are hopeful that this same technique can one day be used safely in human males that become infertile after having chemo or radiation treatments to save their lives from cancer. The entire work was published in the November 2012 journal of Cell Stem Cell.
“This demonstrates in an animal model that in factit’s feasible,” said principal researcher Kyle Orwig, director of the fertility preservation program at the University of Pittsburgh.
According to Kyle Orwig, most of the monkeys in the study were able to produce sperm cells after the implant, and one was even able to fertilize the eggs of a female macaque monkey.
The monkey eggs were fertilized in the lab and grew to the stage where they would have been able to implant in the uterine wall of the female monkey. There were no live baby monkeys produced from this experiment.
Whether or not cancer therapy causes permanent infertility depends on the dosage and type chemotherapy drugs prescribed, along with the part of the body radiated. While this study focused on males the potential for benefiting females make be explored at a later date as well.
In addition to the other long-term adverse effects of chemo or radiation treatments, the uncertainty about whether one can have a family in the future after a childhood cancer is worrisome.
“Cancer patients report that their fertility status has a major impact on their quality of life, both in terms of their psychological well-being, but also their ability to develop relationships,” Orwig said.
In fact, there are several clinics around the world that have preserved testicular tissue from pre-pubescent boys subsequently treated for cancer, “in anticipation that (their) stem cells can be used in the future to achieve a pregnancy,” he said.
“We’re all gambling that things that are in the research pipeline will be translatable to the clinic … I think we’ve demonstrated that it’s feasible and I think this is an important step towards translating it to the clinic.”
Orwig stresses that a great deal more research is necessary before this experimental technique actually be tried in humans. Currently scientists are not able to agree on whether the stem cell-bearing tissue should be transplanted back into a testis.
“Some people think that you should put the cells in as soon as possible before the testis deteriorates to the point where it can’t support sperm production,” he said, referring to completion of treatment and a cancer-free status.
“Some people think you should wait all the way until these boys grow up and are ready to have children, which could be 20 years in the future.”
Currently there is a serious risk associated with this procedure in that there is the potential for cancer cells to be reseeded into a testicle along with the stem cell transplant Before researchers can even try this procedure in humans, this significant risk needs to be dealt with.
Leukemia, for instance, is a cancer of the blood, and that blood circulates through the tissues of the body, including the testes. Testicular tissue removed before treatment could potentially contain cancer cells, Orwig explained.
“And so if you take that tissue out before treatment and then you plan to transplant it back in later, there’s a chance you could re-introduce a cancer,” he said.
According to Orwig this risk is serious and the reason why more pre-clinical research needs to be conducted before clinical trials could be implemented.
“That would be the worst outcome, to re-introduce a cancer into a survivor. That would be terrible,” said Orwig.
According to French researchers who were not involved in this particular study, being able to transplant stem cells in order to produce sperm that is functional, is a major breakthrough even if it was a primate and not a human.
“The work … constitutes a milestone in the field of reproduction and generates hope for restoring fertility in survivors of childhood cancer,” write Virginie Firlej, Pierre Fouchet and Virginie Barraud-Lange of the National Institute of Health and Medical Research in Paris.
They too warn that a great deal of work still needs to happen to ensure the technique is safe before testing in human males can occur, given that the threat of re-introducing cancer to the patient is very real.
Orwig said this procedure would not be available to post-pubescent teens or men treated for cancer and who had not stored a semen sample prior to their chemotherapy and radiation treatments.
“Our study won’t help those men, because they probably don’t have stem cells,” he said.
“We know that chemotherapy and radiation for their cancer or other conditions can cause permanent infertility. And for that reason, a man who desires to have a family after their treatment, they should freeze a sperm sample.
“And there are a variety of ways those sperm can be used in the future to achieve a pregnancy,” including in-vitro fertilization.
Most of us would agree that this is very exciting news. In fact, if you think about it the potential here is astounding. We already know that stem cell research has shown a great deal of potential. The idea that cancer patients might have a new hope for having a family is very exciting. For many it’s the most devastating part of their cancer treatment. But this goes even further than that. The question that comes to mind is whether stem cells could play an even bigger role in cancer patients recovery and return to normal. Stem cell research is certainly on the horizon and we will have to keep an eye on where the future takes it.
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