Several of our recent blog posts have discussed fertility preservation in females, so we’d like to take a little time to shine a light on some interesting oncofertility research focused on males. The Oncofertility Consortium is committed to exploring the reproductive future of all young cancer survivors, and we have several members dedicated to advancing male fertility preservation. While oncofertility in males is relatively straightforward (sperm banking), investigators are currently researching ways to preserve fertility in pre-pubescent males in a procedure called testicular tissue cryopreservation. A chapter entitled, “Fertility Preservation in Males,” in Oncofertility Medical Practice: Clinical Issues and Implementation, authored by Landon Trost, MD, and Robert Brannigan, MD, examines this experimental procedure.
Sperm banking is not an option for prepubertal boys who are not yet producing sperm; however, they do have stem cells in their testes that are poised to begin producing sperm. As a result, investigators are researching other ways to preserve their reproductive function, and testicular tissue cryopreservation is a technique that shows promise. According to the authors, “Although pre-pubertal germ cells do not contain mature [sperm], they do demonstrate the presence of spermatogoniual diploid stem cells, which maintain the capacity to differentiate into mature cells given the appropriate microenvironment.” In other words, the tissue houses immature sperm cells that have the ability to transform into mature, functioning sperm provided the appropriate environment. Researchers are working on protocols that would enable physicians to use the frozen/thawed testicular tissue and stem cells to produce sperm in the laboratory or by re-implanting, years later, back into the individual.
Despite the promise that testicular tissue cryopreservation shows, it’s important to note that this is still an experimental procedure limited to IRB approved research facilities, and currently there is no way to use this tissue for reproductive purposes. There have been no studies to date demonstrating that a technique has been developed to transform the frozen testicular tissue into viable sperm, in vivo or in vitro. The idea behind this procedure is that at some point, technology will evolve enough to use the cryopreserved testicular tissue in assisted reproductive technologies.
Not only are there logistical limitations with the frozen tissue, but there are also some ethical concerns too. According to the authors, “Given the underlying malignancy in patients undergoing testicular tissue extraction, there is concern regarding the potential for reseeding the cancer when the cryopreserved tissue is reintroduced in the native host.” For this reason, and due to the technological factors, testicular tissue cryopreservation is currently very limited. To learn more about male fertility preservation options, please visit www.SaveMyFertility.org.