Urinary Extracellular Domain of Neurotrophin Receptor p75 as a Biomarker for Amyotrophic Lateral Sclerosis in a Chinese cohort

To comprehensively assess whether p75(ECD) in urine could be a candidate biomarker for ALS evaluation. Urine samples were collected from 101 ALS patients, 108 patients with other neurological disease (OND) and 97 healthy controls. 61 ALS patients were followed up with clinical data including ALSFRS-r every 6 to 12 months, 23 ALS patients died and 17 ALS patients lost touch during follow up period. Enzyme-linked immunoassay was employed to determine urine p75(ECD) concentration. The ALSFRS-r was employed to assess the severity of ALS. The concentration of p75ECD in ALS was significantly higher than that of OND and CTRL (p < 0.001). Additionally, urine p75(ECD) concentrations in ALS-definite grade patients were significantly higher than that in ALS-probable grade and ALS-possible grade patients (p < 0.001). Higher urine p75(ECD) concentrations were correlated with increased clinical stage (p = 0.0309); urine p75(ECD) concentrations and ALSFRS-r were negatively correlated (p = 0.022); and urine p75(ECD) concentration in the fast-progressing ALS group was significantly higher than that in slowprogression (p = 0.0026). Our finding indicates that urine p75(ECD) concentration provides additional evidence for patients with clinically suspected ALS, and can be employed to evaluate ALS-severity.