Potential Stemness of Frozen-Thawed Testicular Biopsies without Sperm in Infertile Men Included into the In Vitro Fertilization Programme

We describe the potential stemness of a small amount of frozen-thawed testicular tissue without sperm obtained by biopsy from six patients undergoing assisted reproductive treatment. The patients were diagnosed with Sertoli Cell-Only Syndrome alone or combined with maturation arrest. Trying to provide the natural stem cell niche for cultured stem cells, all isolated cells from enzymatically degraded biopsies where cultured together in different culture media and the presence of putative mesenchymal and putative pluripotent ES-like stem cells was indicated using different methods. High throughput real-time quantitative PCR followed by multivariate analysis revealed the formation of distinct cell clusters reflecting high degree of similarity and some of these cell clusters expressed the genes characteristic for pluripotent stem cells. In the presence of the follicular fluid, prepared as serum, putative testicular stem cells showed a certain degree of plasticity, and spontaneously differentiated into adipose-like and neuronal-like cells. Additionally, using differentiation protocols putative testicular stem cells were differentiated into neuronal- and pancreatic-like cells. This study shows that in assisted reproduction programmes, testicular tissue with no sperm might be an important source of stem cells, although it is discarded in daily medical practice; this requires further research.