Circular RNA-Mediated ceRNA networks predict sperm retrieval outcomes in non-obstructive azoospermia.

INTRODUCTION: Non-obstructive azoospermia (NOA) is a severe form of male infertility in which focal spermatogenesis may persist in otherwise functionally impaired testes. Testicular sperm extraction by microdissection (mTESE) remains the standard procedure for sperm retrieval, but its unpredictable success rate emphasizes the urgent need for reliable, non-invasive biomarkers to support clinical decision-making. Recent advances in transcriptomics have highlighted the role of circular RNAs (circRNAs), microRNAs (miRNAs), and their mRNA targets in the formation of competing endogenous RNA networks (ceRNAs) that regulate spermatogenesis. METHODS: In this study, we identified and validated two novel ceRNA axes, circSH3PXD2A/miR-375-3p/SH3PXD2A and hsa_circ_0037070/miR-487b-3p/ALDH1A3, by integrative bioinformatics and experimental analyses. RESULTS: Both SH3PXD2A and ALDH1A3 were significantly upregulated in NOA patients, while their regulatory miRNAs were downregulated, with circRNA partners showing subtype-specific changes. Importantly, the differences in expression correlated with the mTESE results: NOA - patients (failed recovery) showed more extreme dysregulation than NOA + . Receiver operating characteristic (ROC) curve analysis confirmed the diagnostic potential of these markers, with circRNAs and miRNAs showing high discriminatory power (AUC > 0.90). CONCLUSION: Our results demonstrate that dysregulation of circRNA-miRNA-mRNA networks is a key feature of NOA and that circulating circRNAs and miRNAs can serve as minimally invasive biomarkers for predicting sperm retrieval success. These findings not only improve our understanding of the molecular basis of NOA, but also open up new avenues for precision diagnostics in male infertility.