Issue link: https://viewer.e-digitaledition.com/i/1425002
HISTORICALLY, THE OPTIONS for preserving fertility in boys diagnosed with cancer who have not yet hit puberty have been non-existent. While many children will grow up to have their sperm develop normally, others will not, and without sperm to freeze, prepubescent males have been left with no options. R od T. Mitchel l, M BCh B, Ph D, is one of a nu mber of resea rchers t r y i n g to cha n ge t hat . A s t he P rofessor of Developmenta l Endocrinolog y and Principa l Investigator at MRC Centre for Reproductive Hea lth, Queen's Medica l Research Institute, University of Edinburgh, and a consultant pediatric endocrinologist at The Royal Hospital for Children and Young People in Edinburgh, Dr. Mitchell is working to establish future clinical trials in humans involving testis grafting to produce sperm. " Tra nspla ntation of tissue is, at the moment, the most promising-looking option," Dr. Mitchell says. HOW IT COULD WORK The gist of the idea is this: Before prepubertal boys start cancer treatment, tissue is taken from the testis and cryogenically preserved. Then, a decade or three later, when the man is ready to have children, the tissue is grafted back on, and eventually he will begin producing sperm naturally. (Other current research involves using the same tissue to create sperm in vitro but is not quite as far along.) Studies in rhesus monkeys with testis grafts have proven successful in starting sperm grow th and producing hea lthy offspring. However, ongoing xenotransplantation attempts to replicate this in mice have not yet created sperm. "One of the theories is that the reason it might not be working yet is just purely because you a re putting that tissue from huma ns into mice, a nd the host mouse is just not able to support it properly for whatever reason," Dr. Mitchell says. "I think we're now at the stage where we actua lly need to consider setting up clinica l tria ls … and I think we're on the verge of doing this." MORE SAMPLES ARE NEEDED One problem in establishing clinica l tria ls in humans is that there simply a ren't enough men who a re now old enough, interested in having kids, and infertile. " We've been storing tissue for a relatively short period of time, and not actually that many males have come back wanting the tissue to be used yet," Dr. Mitchell says. But physicians can help by encouraging a ll their eligible prepuberta l cancer patients to freeze testis tissue. "If that 's not offered to a patient before they have their treatment, it's too late then to do any thing," Dr. Mitchell says. "Can we actua lly use it to restore their fertility? The answer is not yet. But we're probably not a long way away." n BY CARI WADE GERVIN RECENT E XPERIMENTAL RESE ARCH SHOWS A PROMISING OUTLOOK FOR CLINICAL TRIAL S IN BOYS. Can Testis Grafting for Boys With Cancer? Preserve Fertility 2 0 SPECIAL CLINICAL SECTION: PEDIATRICS