TY - JOUR
T1 - Urinary p75ECD A prognostic, disease progression, and pharmacodynamic biomarker in ALS
AU - Shepheard, Stephanie R.
AU - Wuu, Joanne
AU - Cardoso, Michell
AU - Wiklendt, Luke
AU - Dinning, Phil G.
AU - Chataway, Tim
AU - Schultz, David
AU - Benatar, Michael
AU - Rogers, Mary Louise
PY - 2017/3/21
Y1 - 2017/3/21
N2 - Objective: To evaluate urinary neurotrophin receptor p75 extracellular domain (p75 ECD) levels as disease progression and prognostic biomarkers in amyotrophic lateral sclerosis (ALS). Methods: The population in this study comprised 45 healthy controls and 54 people with ALS, 31 of whom were sampled longitudinally. Urinary p75 ECD was measured using an enzyme-linked immunoassay and validation included intra-assay and inter-assay coefficients of variation, effect of circadian rhythm, and stability over time at room temperature, 4°C, and repeated freeze-thaw cycles. Longitudinal changes in urinary p75 ECD were examined by mixed model analysis, and the prognostic value of baseline p75 ECD was explored by survival analysis. Results: Confirming our previous findings, p75 ECD was higher in patients with ALS (5.6 ± 2.2 ng/mg creatinine) compared to controls (3.6 ± 1.4 ng/mg creatinine, p < 0.0001). Assay reproducibility was high, with p75 ECD showing stability across repeated freeze-thaw cycles, at room temperature and 4°C for 2 days, and no diurnal variation. Urinary p75 ECD correlated with the revised ALS Functional Rating Scale at first evaluation (r = -0.44, p = 0.008) and across all study visits (r = -0.36, p < 0.0001). p75 ECD also increased as disease progressed at an average rate of 0.19 ng/mg creatinine per month (p < 0.0001). In multivariate prognostic analysis, bulbar onset (hazard ratio [HR] 3.0, p = 0.0035), rate of disease progression from onset to baseline (HR 4.4, p < 0.0001), and baseline p75 ECD (HR 1.3, p = 0.0004) were predictors of survival. Conclusions: The assay for urinary p75 ECD is analytically robust and shows promise as an ALS biomarker with prognostic, disease progression, and potential pharmacodynamic application. Baseline urinary p75 ECD provides prognostic information and is currently the only biological fluid-based biomarker of disease progression.
AB - Objective: To evaluate urinary neurotrophin receptor p75 extracellular domain (p75 ECD) levels as disease progression and prognostic biomarkers in amyotrophic lateral sclerosis (ALS). Methods: The population in this study comprised 45 healthy controls and 54 people with ALS, 31 of whom were sampled longitudinally. Urinary p75 ECD was measured using an enzyme-linked immunoassay and validation included intra-assay and inter-assay coefficients of variation, effect of circadian rhythm, and stability over time at room temperature, 4°C, and repeated freeze-thaw cycles. Longitudinal changes in urinary p75 ECD were examined by mixed model analysis, and the prognostic value of baseline p75 ECD was explored by survival analysis. Results: Confirming our previous findings, p75 ECD was higher in patients with ALS (5.6 ± 2.2 ng/mg creatinine) compared to controls (3.6 ± 1.4 ng/mg creatinine, p < 0.0001). Assay reproducibility was high, with p75 ECD showing stability across repeated freeze-thaw cycles, at room temperature and 4°C for 2 days, and no diurnal variation. Urinary p75 ECD correlated with the revised ALS Functional Rating Scale at first evaluation (r = -0.44, p = 0.008) and across all study visits (r = -0.36, p < 0.0001). p75 ECD also increased as disease progressed at an average rate of 0.19 ng/mg creatinine per month (p < 0.0001). In multivariate prognostic analysis, bulbar onset (hazard ratio [HR] 3.0, p = 0.0035), rate of disease progression from onset to baseline (HR 4.4, p < 0.0001), and baseline p75 ECD (HR 1.3, p = 0.0004) were predictors of survival. Conclusions: The assay for urinary p75 ECD is analytically robust and shows promise as an ALS biomarker with prognostic, disease progression, and potential pharmacodynamic application. Baseline urinary p75 ECD provides prognostic information and is currently the only biological fluid-based biomarker of disease progression.
KW - Amyotrophic lateral sclerosis (ALS)
KW - Urinary p75ECD
KW - Biomarkers
UR - http://www.scopus.com/inward/record.url?scp=85016199947&partnerID=8YFLogxK
U2 - 10.1212/WNL.0000000000003741
DO - 10.1212/WNL.0000000000003741
M3 - Article
C2 - 28228570
VL - 88
SP - 1137
EP - 1143
JO - Neurology
JF - Neurology
SN - 1526-632X
IS - 12
ER -