Abstract: PD08-05
Sources of Funding: None

Introduction

Non-obstructive azoospermia (NOA) is a cause of male infertility secondary to genetically driven defects in spermatogenesis. Testicular sperm extraction (TESE) is successful in identifying small number of sperm in 50% of men with NOA. During TESE, predominantly collapsed seminiferous tubules (ST) are identified with rare areas of dilated STs that are more likely to harbor viable sperm. Hence we hypothesize that miRNA regulated control of mRNA expression along STs leads to optimal environments for spermatogenesis within the human testis.

Methods

STs were obtained from 7 patients, including 3 with NOA, and 2 patients with Sertoli-cell only (SCO). In the three NOA patients, single STs were cut based on the differences in diameter along the same ST into: full/dilated or empty/collapsed tubules. Quantitative PCR was performed on all tubules for GFR?1 and values expressed per vimentin and clusterin. ACTB was used as a housekeeping gene. Expression of GFR?1 was corrected for number of Sertoli cells (vimentin/clusterin). MiRNA expression profiles were determined for each segment of STs and normalized to let-7a. GenEx software was used to identify differentially expressed miRNAs using adjusted p<0.0007 and minimum of 2-fold difference. _x000D_

Results

Quantitative PCR showed a statistically significant decrease in the relative expression of GFR?1 between dilated and collapsed STs (p<0.001) indicating an abnormal number of spermatogonial stem cells (SSC) or spermatogonia. A set of 12 miRNA were identified to be differentially expressed and linked to known signaling pathways in Sertoli cells and SSCs

Conclusions

Our data supports the hypothesis that unique miRNA profiles support normal SSC division that correlate into islands of spermatogenesis, especially in men with NOA. This data in conjunction with previous observations that SSCs are likely present in patients with SCO offers new targets for further research and possible therapeutic intervention

Funding

None