For the first time in history, a unique clinical trial in reproductive medicine has demonstrated success. The transplantation of testicular tissue frozen during the prepubertal stage (before sexual maturity) has fully restored the process of sperm production in an adult patient.
The 27-year-old man had this tissue preserved 16 years ago, at the age of 10, before beginning a rigorous course of chemotherapy for sickle cell disease. While chemotherapy and radiation therapy used for oncological and sickle cell diseases are critical for saving a patient’s life, they often lead to infertility.
Post-pubertal men can freeze their sperm in advance for in vitro fertilization (IVF), but this method was previously unavailable to prepubertal boys. A Belgian clinic began storing tissues from prepubertal patients as early as 2002. In 2008, before undergoing chemotherapy, this patient had one testis removed, which was then divided into small fragments and cryopreserved.
Last year, doctors transplanted four fragments of the frozen tissue into the patient’s remaining testis and another four under the skin of the scrotum. After a year of observation, two fragments placed directly within the testis produced mature spermatozoa, which have already been collected and frozen.
Since the fragments are not directly connected to the seminal duct, the sperm is not released naturally; however, the laboratory-retrieved material is healthy. Scientists must now confirm whether these spermatozoa are capable of fertilizing an egg. According to Professor Rod Mitchell, a pediatric endocrinologist at the University of Edinburgh, this milestone proves that the approach truly works in humans.
Currently, similar tissue from over 3,000 patients is stored worldwide. The first successful patient is now considering whether to undergo a second stage of transplantation to collect an additional supply of sperm or to proceed directly to in vitro fertilization (IVF).
