Testicular tissue cryopreservation: 8 years of experience from a coordinated network of academic centers

Abstract

STUDY QUESTION Is it feasible to disseminate testicular tissue cryopreservation with a standardized protocol through a coordinated network of centers and provide centralized processing/freezing for centers that do not have those capabilities? SUMMARY ANSWER Centralized processing and freezing of testicular tissue from multiple sites is feasible and accelerates recruitment, providing the statistical power to make inferences that may inform fertility preservation practice. WHAT IS KNOWN ALREADY Several centers in the USA and abroad are preserving testicular biopsies for patients who cannot preserve sperm in anticipation that cell- or tissue-based therapies can be used in the future to generate sperm and offspring. STUDY DESIGN, SIZE, DURATION Testicular tissue samples from 189 patients were cryopreserved between January 2011 and November 2018. Medical diagnosis, previous chemotherapy exposure, tissue weight, and presence of germ cells were recorded. PARTICIPANTS/MATERIALS, SETTING, METHODS Human testicular tissue samples were obtained from patients undergoing treatments likely to cause infertility. Twenty five percent of the patient’s tissue was donated to research and 75% was stored for patient’s future use. The tissue was weighed, and research tissue was fixed for histological analysis with Periodic acid-Schiff hematoxylin staining and/or immunofluorescence staining for DEAD-box helicase 4, and/or undifferentiated embryonic cell transcription factor 1. MAIN RESULTS AND THE ROLE OF CHANCE The average age of fertility preservation patients was 7.9 (SD = 5) years and ranged from 5 months to 34 years. The average amount of tissue collected was 411.3 (SD = 837.3) mg and ranged from 14.4 mg—6880.2 mg. Malignancies ( n = 118) were the most common indication for testicular tissue freezing, followed by blood disorders ( n = 45) and other conditions ( n = 26). Thirty nine percent ( n = 74) of patients had initiated their chemotherapy prior to undergoing testicular biopsy. Of the 189 patients recruited to date, 137 have been analyzed for the presence of germ cells and germ cells were confirmed in 132. LIMITATIONS, REASONS FOR CAUTION This is a descriptive study of testicular tissues obtained from patients who were at risk of infertility. The function of spermatogonia in those biopsies could not be tested by transplantation due limited sample size. WIDER IMPLICATIONS OF THE FINDINGS Patients and/or guardians are willing to pursue an experimental fertility preservation procedure when no alternatives are available. Our coordinated network of centers found that many patients request fertility preservation after initiating gonadotoxic therapies. This study demonstrates that undifferentiated...

Development and Disease-Dependent Dynamics of Spermatogonial Subpopulations in Human Testicular Tissues

“…Due to limited access to healthy pre/pubertal testicular tissue, in our study, the spermatogonial expression patterns during testicular development were established for untreated cancer patients without any preexisting (congenital) risk factors for impaired testicular function. Reassuringly, Stukenborg et al and Valli-Pulaski et al recently reported that spermatogonial numbers per tubular cross section of untreated cancer patients were within the confidence interval of spermatogonial reference values previously established in healthy boys [10,15,21].…”

“…The numbers of total [21] and undifferentiated (UTF1-positive) [15] spermatogonial populations, as well as proliferative activity [20] are known to vary within age groups. In our patient cohort, the density of MAGEA4-, UTF1-and PCNA-positive spermatogonia showed a trend to increase with age, however without significance.…”

“…In contrast, a significant spermatogonial depletion was observed in boys receiving alkylating therapies [9,10]. Recently, Valli-Pulaski et al showed in a cohort of 137 patients no impact of previous exposure to either alkylating or non-alkylating chemotherapy on the number of UTF1-positive spermatogonia compared with patients prior to treatment [15]. This contradicting outcome may be due to the different approaches for spermatogonial quantification between studies.…”

“…Descriptive and qualitative information of the heterogeneous prepubertal testicular tissues is pivotal to determine its potential use in fertility restoration strategies. While accumulating evidence on spermatogonial numbers in bio-banked tissues is reported, evaluation of molecular properties of spermatogonia remains limited [4,5,9,10,15].…”

Fertility sparing strategies for pre- and peripubertal male cancer patients

“…Cryopreservation of immature testicular tissue is now proposed in a growing number of clinics. National and international networks have been established in Europe and the USA to enhance access and allow sample routing to facilities that meet the local regulations on human tissue and cell banking [7,15,16]. Reported complication rates due to the biopsy procedures are low [17].…”