Background: There is a lack of biomarkers for distinguishing non-obstructive azoospermia (NOA) patients with successful sperm retrieval (Sp+) from those with failed sperm retrieval (Sp-). This study aimed to determine the potential of extracellular vesicles tRNA-derived small RNA (tsRNA) as a novel non-invasive biomarker for successful sperm retrieval by microdissection testicular sperm extraction (mTESE).
Methods: The study included 18 patients with NOA with successful sperm retrieval (Sp+) and 23 patients with NOA with failed sperm retrieval (Sp-), 15 obstructive azoospermia (OA) patients, 5 idiopathic oligospermia (IO) patients, and 12 healthy people. Seminal plasma extracellular vesicles tsRNA levels were used in a two-stage case-control study (screened by tsRNA sequencing on Illumina NextSeq instrument and validated by qRT-PCR). The bioinformatic analysis was performed to determine the role of tsRNA in the pathogenesis of non-obstructive azoospermia.
Results: Two tsRNAs (tRF-Val-AAC-010: AUC = 0.96, specificity = 80%, sensitivity = 95%; tRF-Pro-AGG-003: AUC = 0.96, specificity = 87%, sensitivity = 95%) were found to have high predictive accuracy for distinguishing the origin of azoospermia. In addition, the extracellular vesicles tRF-Val-AAC-010 resulted in high predictive ability (AUC = 0.89, sensitivity = 72%, specificity = 91%, P < 0.0001) in predicting the presence of sperm in non-obstructive azoospermia undergoing mTESE. Finally, bioinformatic analysis revealed that tRF-Val-AAC-010 were involved in spermatogenesis.
Conclusions: This study identified that the extracellular vesicles tRF-Val-AAC-010 and tRF-Pro-AGG-003 are biomarkers for the diagnosis of non-obstructive azoospermia, and that tRF-Val-AAC-010 as a potential non-invasive biomarker for predicting the presence of sperm in non-obstructive azoospermia testicular tissue.
Keywords: Biomarker; Extracellular vesicles; Non-obstructive azoospermia; Obstructive azoospermia; tsRNA.
© 2022. The Author(s).