The Small RNA Landscape in Azoospermia: Implications for Male Infertility and Sperm Retrieval—A Preliminary Study

MicroRNAs (miRNAs), a class of small noncoding RNAs, play a crucial role in spermatogenesis. However, their specific expression patterns in azoospermic patients, particularly in relation to sperm presence and pregnancy outcomes, remain underexplored. We performed small RNA sequencing on forty testicular tissue samples from idiopathic azoospermic and cryptozoospermic patients who underwent testicular sperm extraction (TESE). Differentially expressed (DE) miRNAs were identified across groups with high, rare, or no spermatozoa presence, as well as between individuals with successful and unsuccessful pregnancies following assisted reproduction. Functional enrichment analyses were conducted to assess the biological relevance of miRNA alterations. Our findings revealed distinct miRNA expression patterns linked to sperm presence and pregnancy outcomes. Samples with high sperm presence exhibited reduced miRNA expression, while those with impaired spermatogenesis demonstrated upregulated miRNAs associated with cell survival and differentiation pathways. Several regulatory pathways were also disrupted in samples leading to unsuccessful pregnancies, including the estrogen signaling receptor (ESR) pathway, interleukin-4 and interleukin-13 signaling, and transcription networks. This study highlights miRNA-mediated regulatory differences in azoospermic patients, identifying potential biomarkers for sperm retrieval success and fertility outcomes. Future validation and multi-omics approaches are needed to confirm these findings and enhance male infertility diagnostics.