ABSTRACT
Objective To explore the correlation between apolipoprotein E (ApoE) gene polymorphism and urine Alzheimer-associated neuronal thread protein (AD7c-NTP) level in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI).Methods The cognitive function of 30 AD patients (AD group),30 MCI patients (MCI group) and 30 normal controls (NC group) was evaluated by neuropsychological batteries like MMSE,the Cambridge Cognitive Examination-Chinese Version (CAMCOG-C),etc.ELISA was used to test the urine level of AD7c-NTP.The genotypes of ApoE were analyzed by the high-resolution melting assay in blood samples.Results Compared with the NC group (0.59 (0.40,0.66) ng/ml),the urine level of AD7c-NTP in the AD group (1.03(0.80,1.41) ng/ml) and the MCI group (0.69(0.53,0.91) ng/ml) was increased (Z =33.727,P ＜0.01).The urine level of AD7c-NTP in the AD group was higher than that in the MCI group (Z =8.232,P ＜ 0.05).The level of AD7c-NTP in urine was negatively correlated with MMSE and CAMCOG-C scores (rMMSE =-0.604,P ＜ 0.01;rCAMCOG-C =-0.486,P ＜ 0.01).According to receiver operating characteristic curve,the optimal cutoff point of AD7c-NTP in urine for diagnosis of patients including AD and MCI was 0.70 ng/ml,with sensitivity of 71.7％ and specificity of 83.3％,and area under the curve of 0.82 (95％ CI 0.73-0.90,P ＜0.05).There were four genotypes comprising ε2/3,ε3/3,ε3/4 and ε4/4 for ApoE gene.The frequencies of ε4 carriers were 46.7％ (14/30),23.3％ (7/30) and 23.3％ (7/30) in the AD,MCI and NC groups,respectively.There was a notable increase in urine AD7c-NTP and a significant decrease in CAMCOG-C scores in MCI patients who harbored the ApoE ε4 allele (ZAD7c-NTP =4.857,P ＜ 0.05;ZCAMCOG-C =4.284,P ＜0.05).Conclusions The urine level of AD7c-NTP was significantly increased in AD and MCI patients,the higher the level of AD7c-NTP,the more serious the cognitive impairment.The ε4 carriers exhibited higher urine level of AD7c-NTP,but worse cognitive function compared to ε4 non-carriers in the MCI group.
ABSTRACT
Objective To explore the diagnostic value of Alzheimer-associated neuronal thread protein(AD7C-NTP)and olfactory function in the differentiation of three types of dementia,and to evaluate their clinical application value.Methods Mini-Mental State Examination (MMSE)and Montreal Cognitive Assessment(MoCA)were applied to evaluate cognitive function of all subjects with Alzheimer disease(AD),frontotemporal dementia (FTLD),or mixed dementia (MD).Enzyme-linked immunosorbent assay(ELISA)was used to detect the expression levels of AD7c-NTP in urine.T&T test method was applied to detect the olfactory function.Spearman rank correlation was used to evaluate the correlation of urine AD7c NTP with MMSE and MoCA scores.Results There was no significant difference in the demographic profile (except age)among three types of dementia of AD,FTLD and MD(F =4.05,P =0.02).Among the three dementia groups,the mean age of the MD group was highest.The statistically significant difference in MMSE scores was found among the three groups(F 3.79,P=0.03),while there was no significant difference inMoCAand NPI scores among the three dementia groups.The levels of the urine AD7c-NTP were different among the three dementia groups,but without statistical significance(H 1.25,P =0.53).Additionally,the FTLD group had the highest urine AD7c NTP level.Spearman rank correlation analysis showed no correlation of AD7c-NTP with MMSE and MoCA(r =0.18,P =0.25;r =0.14,P =0.39,respectively).No differences in olfactory function of the recognition domain(H =3.40,P=0.18)and in the detection domain(H =2.07,P=0.36)were found among three dementia groups of AD,FTLD and MD.Conclusions The level of urine AD7c-NTP is not of clinical significance in differentiating three types of dementia,and it is not correlated with the MMSE and MoCA scores.This study fails to find the clinical value of olfactory function test for distinguishing three types of dementia.