Men With Chronic Orchialgia Exhibit Differential Neuroinflammatory Gene Expression Relative to Asymptomatic Controls

To identify differences in neuroinflammatory gene expression in individuals with chronic orchialgia (CO) compared to asymptomatic controls.

Vas deferens, spermatic cord fascia, blood, and urine were collected from 9 men with CO at time of microscopic spermatic cord denervation and 7 asymptomatic controls at time of vasectomy. RNA was isolated and analyzed with the NanoString Human Neuroinflammation panel. Data were normalized, gene expression fold changes and enriched pathways relative to asymptomatic controls were determined. Gene expression was considered significantly different if there was a >2-fold change and P-value <.05 relative to controls.

Mean patient age was 51 years and median symptom duration 12 months. There were 26 genes with significantly differential expression in vas deferens. cFos, a marker of nociceptive pain, had the greatest difference (30.2-fold change, P <.000001). Enriched pathways in vas deferens included nerve function, matrix remodeling, and innate immune responses. In fascia, cFos also had the greatest differential expression (38-fold, P = .000002), followed by S100A12 (11-fold, inducer of innate immune response). Enriched pathways in fascia included nerve function and inflammation. In blood, there were no differentially expressed genes, and in urine there were 95 differentially expressed genes.

Men with CO have a diverse set of neuroinflammatory genes with differential expression in tissue and urine relative to healthy controls. These findings confirm pathologic changes in tissue targeted by denervation surgery, and suggest molecular changes in neuropathic pain that could lead to biomarker identification and novel treatment.