Urinary p75^ECD levels in patients with amyotrophic lateral sclerosis: a meta-analysis

Objective: p75 neurotrophin receptor (p75^NTR) is associated with the pathogenesis of amyotrophic lateral sclerosis (ALS). However, its role is not fully understood. The aim of this study was to evaluate the association between ALS and the extracellular domain of p75^NTR(p75^ECD) in urine. Methods: We conducted a comprehensive literature search using keywords in the PubMed, Embase, Science, and the Cochrane Library, and identified five case control studies, with the latest date of search being 18 April 2021. Results: The results showed that urinary p75^ECD levels were significantly higher in patients with ALS compared to non-neurological control (weighted mean difference (WMD) = 4.18, 95% CI [2.525, 6.990], p < 0.001), and other neurological diseases (WMD = 6.005, 95% CI [1.596, 10.414], p = 0.008). Increased urinary p75^ECD levels were inversely associated with ALSFRS-R in ALS patients (r = -0.32, 95% CI [-0.43, -0.21], p < 0.001). Conclusions: Given the associations between p75^ECD and ALS found in this meta-analysis, urinary p75^ECD levels have potential to be used as a diagnostic biomarker and a progression indicator in the future.