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WASHINGTON – Scientists are increasingly looking to help young boys undergoing cancer treatment to preserve their future fertility – and evidence is the first monkey born from experimental technology.
More and more people are surviving childhood cancer, but nearly 1 in 3 will remain infertile because of life-saving chemotherapy or radiation therapy.
When cancer is diagnosed in young adults, they can freeze sperm, eggs or embryos before treatment. But children diagnosed before puberty can not do so because they do not yet produce mature eggs or spermatozoa.
"Fertility problems in children with cancer have been ignored" for years, said reproductive scientist Kyle Orwig of the University of Pittsburgh. "Many of us dream of growing up and having their own family. We hope that our research will help these young patients to do so. "
The Orwig team reported a breakthrough Thursday: first, it froze some testicular tissue in a monkey who has not yet reached puberty. Later, they used it to produce sperm that, thanks to a version for monkey from IVF, gave birth to a healthy monkey called Grady.
The technique worked pretty well so that the tests on humans could begin in the next few years, said Orwig.
"This is a huge step forward" that should provide hope for families, said Susan Taymans of the National Institute of Child Health and Human Development, who helped fund the research published in the report. Science magazine. "It's not like science fiction. This is something that seems quite achievable.
The University of Pittsburgh Medical Center and a handful of other hospitals are already freezing immature testicular tissue from young cancer patients, hoping to know how to use it once they're tall and ready to have their own children.
Boys are born with stem cells inside small tubes in the testes, cells that begin to produce sperm after the testosterone shake of puberty. Orwig's goal: Protect stem cells that produce sperm from cancer treatment by freezing small pieces of testicular tissue and using them to restore fertility later in life.
How? Enter the monkey search.
The Orwig team froze the tissues of young male monkeys and sterilized them. Once the monkeys approached puberty, the researchers thawed these tissue samples and returned them to the original animal – implanting them just under the skin.
"We do not connect it to normal plumbing," warned Orwig.
Reinforced by hormones, small pieces of tissue have developed. Months later, the researchers removed them. Of course, inside, there was sperm that they could collect and freeze.
Colleagues at Oregon's National Primate Research Center injected some of this sperm into the eggs of female monkeys and implanted the resulting embryos. Last April, Grady was born and "she plays and behaves like any other monkey that has grown normally," Orwig said.
If the technique seems a little weird, it looks like a feminine option.
Girls' eggs are immature before puberty. The researchers removed and frozen strips of ovarian tissue containing egg follicles from young women prior to cancer treatment, in the hope that, once grafted, the immature eggs would resume their development. It is considered experimental even for young adults, but some births have been reported. Now, some hospitals also store ovarian tissue in girls.
Surgery involving boys' testicular tissue is less invasive, noted Orwig, who is also looking for ways to reinsert sperm-producing stem cells where they belong, rather than the more diverted technique.
The new study shows that "immature testicular tissue can become an option" to preserve the fertility of boys, wrote Nina Neuhaus and Stefan Schlatt of the Center for Reproductive Medicine and Andrology of Münster, Germany, in a editorial.
At the same time, "it's important for parents to know about it," said Christine Hanlon of Holiday, Florida, who took her son Dylan to Pittsburgh to have his tissue preserved while he was diagnosed with sarcoma at 9 years old.
Today, Dylan is a healthy teenager, and no one knows where he will ever need stored tissues, any of the 200 samples that Orwig 's study has retained. But Hanlon was delighted to learn that research is ahead, just in case.
"You lose a part of your childhood in the treatment of cancer," Hanlon said. "There was a chance that I could help her to have a normal life in her future, with the potential to have a family if that's what it's about." decided to do, I wanted to be able to do it. "
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