Spermatogonia Loss Correlates with LAMA 1 Expression in Human Prepubertal Testes Stored for Fertility Preservation

Fertility preservation for male childhood cancer survivors not yet capable of producing mature spermatozoa, relies on experimental approaches such as testicular explant culture. Although the first steps in somatic maturation can be observed in human testicular explant cultures, germ cell depletion is a common obstacle. Hence, understanding the spermatogonial stem cell (SSC) niche environment and in particular, specific components such as the seminiferous basement membrane (BM) will allow progression of testicular explant cultures. Here, we revealed that the seminiferous BM is established from 6 weeks post conception with the expression of laminin alpha 1 (LAMA 1) and type IV collagen, which persist as key components throughout development. With prepubertal testicular explant culture we found that seminiferous LAMA 1 expression is disrupted and depleted with culture time correlating with germ cell loss. These findings highlight the importance of LAMA 1 for the human SSC niche and its sensitivity to culture conditions.Peer reviewe

Reference standards for follicular density in ovarian cortex from birth to sexual maturity

Research question: Are age-normalized reference values for human ovarian cortical follicular density adequate for tissue quality control in fertility preservation?Design: Published quantitative data on the number of follicles in samples without known ovarian pathology were converted into cortical densities to create reference values. Next, a sample cohort of 126 girls (age 1-24 years, mean +/- SD 11 +/- 6) with cancer, severe haematological disease or Turner syndrome were used to calculate Z-scores for cortical follicular density based on the reference values.Results: No difference was observed between Z-scores in samples from untreated patients (0.3 +/- 3.5, n = 30) and patients treated with (0.5 +/- 2.9, n = 48) and without (0.1 +/- 1.3, n = 6) alkylating chemotherapy. Z-scores were not correlated with increasing cumulative exposure to cytostatics. Nevertheless, Z-scores in young treated patients (0-2 years -2.1 +/- 3.1, n = 10, P = 0.04) were significantly lower than Z-scores in older treated patients (11-19 years, 2 +/- 1.9, n = 15). Samples from patients with Turner syndrome differed significantly from samples from untreated patients (-5.2 +/- 5.1, n = 24, P = 0.003), and a Z-score of -1.7 was identified as a cut-off showing good diagnostic value for identification of patients with Turner syndrome with reduced ovarian reserve. When this cut-off was applied to other patients, analysis showed that those with indications for reduced ovarian reserve (n = 15) were significantly younger (5.9 +/- 4.2 versus 10.7 +/- 5.9 years, P = 0.004) and, when untreated, more often had non-malignant haematologic diseases compared with those with normal ovarian reserve (n = 24, 100% versus 19%, P = 0.009).Conclusion: Z-scores allow the estimation of genetic- and treatment-related effects on follicular density in cortical tissue from young patients stored for fertility preservation. Understanding the quality of cryopreserved tissue facilitates its use during patient counselling. More research is needed regarding the cytostatic effects found in this study.Peer reviewe