One in three childhood cancer survivors is at risk of becoming infertile due to chemotherapy or radiation, and since their sperm or eggs have not matured, assisted reproduction using those sperm or eggs is not an option when they become adults. Now, in a major first, researchers at the University of Pittsburgh School of Medicine and the Magee-Womens Research Institute (MWRI) have reported in a non-human primate model that immature testicular tissue can be cryopreserved, and later used to restore fertility to the same animal.
The advance, reported in Science, offers hope for fertility preservation in prepubertal boys who are about to undergo cancer treatments, the researchers report. “This advance is an important step toward offering young cancer patients around the world a chance at having a family in the future,” said the study’s senior author Kyle Orwig, Ph.D., professor of obstetrics, gynecology and reproductive sciences at Pitt’s School of Medicine and an MWRI investigator.
In the study, Orwig and his team developed a non-human primate model of cancer survivorship. Prior to treating with chemotherapy, the researchers cryopreserved immature testicular tissue. They later thawed and transplanted pieces of the tissue under the skin of the same animal. Eight to 12 months later, after the animals entered puberty, the researchers removed the grafts and found large numbers of sperm to be present. They sent the sperm to their collaborators at the Oregon National Primate Research Center at Oregon Health and Science University who were able to generate viable embryos, which were then transferred to recipient females.
In April 2018, one of the females gave birth to a healthy female baby, which Orwig named “Grady” — a portmanteau of “graft-derived” and “baby.” “With Grady’s birth, we were able to show proof-of-principle that we can cryopreserve prepubertal testicular tissue, and later use it to restore fertility as an adult,” the researchers said.