Value of urine Alzheimer-associated neuronal thread protein level for diagnosing dementia

Abstract

Objective To investigate the value of Alzheimer-associated neuronal thread protein (AD7c-NTP) level in urine for diagnosing dementia.  Methods Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were applied to evaluate cognitive function of all subjects. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expression changes of urine AD7c-NTP. Spearman rank correlation was used to evaluate the correlation of urine AD7c-NTP with MMSE and MoCA scores. Receiver operating characteristic (ROC) curve was used to estimate the sensitivity, specificity and accuracy rate of AD7c-NTP on diagnosing dementia.  Results There were 57 cases with Alzheimer's disease (AD), 30 cases with amnesic mild cognitive impairment (aMCI), 37 cases with frontotemporal dementia (FTD), 32 cases with vascular dementia (VaD) and 20 normal controls. There was statistically significant difference of urine AD7c-NTP levels among different groups (P = 0.000). The levels of urine AD7c-NTP in AD group, aMCI group and FTD group were significantly higher than that of control group (P = 0.000, 0.029, 0.005). The level of urine AD7c-NTP in moderate to severe AD group was higher than that of mild AD group, but there was no significant difference (P = 0.359). The level of urine AD7c-NTP was negatively related with MoCA score in mild AD group (r_s = -0.506, P = 0.016), and there was no significant correlation of urine AD7c-NTP with MMSE and MoCA scores in moderate to severe AD group (P > 0.05, for all). In ROC analysis, area under the curve (AUC) was 0.838 (95% CI: 0.732-0.945, P = 0.000), with 70.20% sensitivity and 90% specificity, and the critical value for diagnosing AD was 2.32 ng/ml of urine AD7c-NTP. There were 70.18% (40/57) of AD patients, 63.33% (19/30) of aMCI patients and 45.95% (17/37) of FTD patients had abnormal levels of urine AD7c-NTP (> 2.32 ng/ml).  Conclusions AD7c-NTP level in urine has important clinical value in early diagnosis and condition assessment of patients with dementia.

DOI: 10.3969/j.issn.1672-6731.2015.08.009