Excessive Urinary p75ecd is a Potential Indicator of Amyotrophic Lateral Sclerosis: An American Cohort Study

Introduction: Amyotrophic lateral sclerosis (ALS) is an idiopathic, fatal, and rapidly progressive neurodegenerative disease. At present, neurofilament light (NFL) and phosphorylated neurofilament heavy (pNfH) proteins in biological fluids are commonly known prognostic biomarkers, but their levels stabilize over time. Thus, there is a critical gap in the field to identify unique biomarkers that can aid disease diagnosis, progression and monitoring the therapy response. Aim: To evaluate the presence of extracellular domain of p75 (p75ecd) in urine of ALS patients and healthy control volunteers in the North American cohort. Method: An enzyme-linked immunoassay (ELISA) and creatinine assay was used to determine the levels of p75ecd and creatinine in the urine of ALS patients and healthy control volunteers respectively. This assay demonstrated clear discrimination in the levels of the p75ecd in the urine samples of ALS patients as compared to healthy individuals. Results: It was found that the concentration of p75ecd in ALS samples was significantly higher than that of healthy controls group. Additionally, high p75ecd levels were segregated with respect to age, sex, family history, occupation and drug treatment, medication status. Moreover, we observed differential expression patterns among the different stages of the disease. Our results followed the pattern that was observed in the Chinese, and Australian cohort. Conclusion: Altogether, our results indicate that the development of an efficient system for the detection of elevated levels of p75ecd in the urine could serve as a useful modality for early ALS diagnosis, disease progression, and monitoring the effectiveness of therapeutic interventions.