Circulatory exosomal tRF-Glu-CTC-005 and tRF-Gly-GCC-002 serve as predictive factors of successful microdissection testicular sperm extraction in patients with nonobstructive azoospermia

Abstract

To identify circulating plasma exosomal transfer RNA-derived fragments (tRFs) as the predictive factors of successful microdissection testicular sperm extraction (micro-TESE) in patients with nonobstructive azoospermia (NOA). Case and control prospective study. Academic research laboratory. Twelve patients with NOA with successful sperm retrieval by micro-TESE, 18 patients with NOA with failed sperm retrieval by micro-TESE, and 12 normozoospermic fertile controls. Blood samples were collected from participants. The abundance of tRFs normalized as counts per million of the total aligned reads with the next-generation sequencing system; candidate tRF levels were validated through quantitative reverse transcription polymerase chain reaction; predictive accuracy was evaluated by the receiver operating characteristic area under the curve analysis. The nomogram was built for ranking. The plasma circulating exosomal tRF-Gly-GCC-002 and tRF-Glu-CTC-005 manifested the most confident differential expression between patients with NOA with successful sperm retrieval by micro-TESE and patients with NOA with failed sperm retrieval by micro-TESE. The target gene prediction of these 2 tRFs followed by the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis indicated the functional enrichment of neuroendocrine protein metabolism and striatum/subpallium development. The herpes simplex virus 1 infection pathway was also involved. The receiver operating characteristic area under the curve (AUC) analysis demonstrated a promising predictive accuracy: tRF-Gly-GCC-002, AUC of 0.921, and tRF-Glu-CTC-005, AUC of 0.954. A regression model was built and presented with the nomogram for further assessment. This study described the exosomal tRF-Gly-GCC-002 and tRF-Glu-CTC-005 expression values, indicated a promising predictive effect for accessibility of sperm retrieval through micro-TESE from patients with NOA, and highlighted tRF-Gly-GCC-002 and tRF-Glu-CTC-005 as useful biomarkers in patients with NOA seeking invitro conception with their residual sperm.