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Baby Monkey Born Using Frozen Testicular Tissue, Giving Hope for Infertile Childhood Cancer Survivors

Around 30 percent of pediatric cancer patients are rendered infertile by chemotherapy or radiation treatments

Grady's mother gave birth via caesarean section on April 16, 2018 (OHSU)
smithsonian.com

Going through chemotherapy and radiation can permanently damage a cancer patient's genitals, leaving the person infertile. For adult male cancer patients, their sperm can be frozen before treatment. But that's not an option for boys who haven't yet reached puberty and started producing semen yet, which restricts their ability to possibly start a family of their own someday. With the survival rate of childhood cancer now close to 80 percent, the need for a solution is increasing.

A promising option was reported last week when, for the first time ever, a healthy baby macaque monkey was born using frozen testicular tissue from a primate parent that underwent cancer treatment, as detailed in the journal Science. If the baby monkey continues to mature normally, researchers will be one step closer to replicating the process in humans, opening a pathway for the roughly 30 percent of pediatric cancer survivors rendered infertile by chemotherapy and radiation to one day have their own biological offspring, reports Sarah Sloat for Inverse.

For the new study, a team of researchers from the United States and Canada surgically removed and then froze testicular tissue from five prepubescent macaques before treating them with chemotherapy. According to National Geographic’s Maya Wei-Haas, the scientists waited until the monkeys reached puberty, at which point they removed the animals’ remaining testicles, unfroze the tissue samples taken earlier, grafted the two together and then reattached the graft under the five subjects’ skin, either at the scrotum or on their backs.

Within eight to 12 months, the transplanted grafts had produced enough sperm to artificially fertilize 138 eggs. Of these eggs, Motherboard’s Sarah Emerson notes, 11 matured into viable embryos ready for implantation in six female monkeys. Only one of the six ultimately became pregnant. On April 16, 2018, the mother successfully delivered a healthy female baby monkey via caesarean section, which the team name Grady, a combination of “graft-derived” and “baby.”

Despite the unusual nature of her creation, Grady appears to be just like her macaque peers, adhering to typical playtime habits and social development milestones.

“She's just a regular monkey, believe it or not,” senior author Kyle Orwig, a reproductive biologist at the University of Pittsburgh School of Medicine, explains to the Los Angeles Times’ Emily Baumgaertner.

Orwig and his colleagues hope that their proof-of-concept study will soon pave the way for human clinical trials. Still, Scientific American’s Emily Mullin observes, there are several research questions that must be addressed before the procedure can be safely implemented. One major concern revolves around transplanted tissue, which can’t be easily reconnected with the normal “plumbing” of the male reproductive system. As a result, conception will likely require the tissue to be removed and dissected to release sperm, then made viable with the help of assisted reproductive technology, including artificial insemination and in vitro fertilization.

A second area of interest is ensuring that frozen testicular tissue doesn’t hold cancerous cells. Samples collected from patients with blood cancers, such as leukemia and lymphoma, could contain lingering traces of disease, Baumgaertner notes for the Los Angeles Times, and would therefore “resurrect” the very issue that caused infertility in the first place.

“If I were a parent of a prepubescent child facing this diagnosis, I would be pretty quick to volunteer for something of this nature, to give him that possibility of fatherhood in the future,” Orwig concludes to Baumgaertner. “That's something I wish I could offer these men that I'm now seeing at 30 or 35 years old.”

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