Liquid chromatography-mass spectrometry identification of serum biomarkers for nocturia in aged men

Purpose We aimed to investigate the association between nocturia and serum metabolites identified using metabolomics analysis. Methods This study enrolled 66 men aged 65-80 years, recruited from the outpatient department of a university hospital. The participants were stratified as follows: Nocturia group [45 men with any total international prostate symptom score (IPSS) and an average of 3 nights = 1.5 micturitions/night] and Control group (21 men with total IPSS < 8 and an average of 3 nights < 1.5 micturitions/night). The 24-h frequency-volume chart, IPSS, and Quality-of-Life questionnaire were used to evaluate micturition behavior. Serum metabolite profiles were obtained using liquid chromatography-mass spectrometry (LC-MS)-based metabolomics analysis and compared between the two groups using the unpaired t test. The relationship between serum metabolites and nocturia was determined using multivariable logistic regression analysis. Results There were no differences in background factors between the Nocturia and Control groups. In the IPSS, mean total scores in the Nocturia and Control groups were 12.4 and 4.0, respectively. On frequency-volume chart analysis, nocturnal urine volume and micturition frequency during daytime and nighttime were significantly higher in the Nocturia group. LC-MS highlighted 13 serum metabolites as potential biomarkers of nocturia. On multivariate analysis, increased levels of palmitoylethanolamide, 4-hydroxydocosahexaenoic acid, 9-hydroxyoctadecadienoic acid, 20-hydroxydocosahexaenoic acid, 13-hydroxyoctadecadienoic acid, arachidonoylethanolamide, eicosapentaenoic acid, 12-hydroxy-eicosatetraenoic acid, and arachidonic acid were associated with nocturia. Conclusions In aged men, the pathogenesis of nocturia involves abnormal metabolism in several signaling pathways involving omega-3 and omega-6 polyunsaturated fatty acids, as well as endocannabinoids.