Effects of Hepatorenal Function on Urinary Alzheimer-Associated Neuronal Thread Protein: A Laboratory-Based Cross-Sectional Study Among the Older Chinese Population.

Background: Urinary Alzheimer-associated neuronal thread protein (AD7c-NTP) is a biomarker for the early diagnosis of Alzheimer's disease (AD). It remains unclear whether hepatorenal function affects the urinary AD7c-NTP level. Objective: To evaluate the effects of hepatorenal function on urinary AD7c-NTP level. Methods: We enrolled 453 participants aged 60-100 years. An automated chemistry analyzer was used to determine the indicators of serum hepatorenal function. Enzyme-linked immunosorbent assay was used to measure the urinary AD7c-NTP level. Results: Spearman's correlation analysis showed a negative correlation between urinary AD7c-NTP levels and indicators of hepatorenal function, including albumin (r = -0.181, p < 0.001), albumin/globulin ratio (r = -0.224, p < 0.001), cholinesterase (r = -0.094, p = 0.046), total carbon dioxide (r = -0.102, p = 0.030), and glomerular filtration rate (r = -0.260, p < 0.001), as well as a positive correlation with globulin (r = 0.141, p = 0.003), aspartate transaminase (r = 0.186, p < 0.001), blood urine nitrogen (r = 0.210, p < 0.001), creatinine (r = 0.202, p < 0.001), uric acid (r = 0.229, p < 0.001), and cystatin C (r = 0.265, p < 0.001). The least absolute shrinkage and selection operator (LASSO) regression analysis and multiple linear regression model analyses showed that the statistically significant hepatorenal indicators for predicting AD7c-NTP were A/G (p = 0.007), AST (p = 0.002), BUN (p = 0.019), and UA (p = 0.003). Conclusions: The effects of hepatorenal indicators should be considered when using urinary AD7c-NTP levels in clinical settings.

Incidental Finding: Urine Alzheimer-Associated Neuronal Thread Protein (AD7c-NTP) and Serum Vitamin D25.

BACKGROUND: National and international experts have been attempting to find diagnostic tools for the early identification of symptoms to facilitate early identification and intervention of the disease. OBJECTIVE: Detection of urine Alzheimer-associated neuronal thread protein (AD7c-NTP) and serum 25-hydroxyvitamin D (25(OH)D) in the diagnosis of Alzheimer's disease (AD). METHODS: Subjects aged >50 years who underwent a physical examination at the Taihu Sanatorium of Jiangsu Province, had no clinical evidence of AD-related issues, and had normal Mini-Mental State Exam and Montreal Cognitive Assessment scores were enrolled in the present study. There were 35 males and 15 females, who were aged 51-91 years. Urine AD7c-NTP levels and serum 25(OH)D concentrations were measured. RESULTS: The Pearson correlation analysis revealed that the urine AD7c-NTP levels in these subjects were negatively correlated with the serum 25(OH)D concentrations (r = -0.460, p < 0.001). CONCLUSION: Combined with previous studies, it was considered that cognitive function might be the only link for the correlation between AD7c-NTP and 25(OH)D. This finding might provide a starting point to investigate the potential value of the interaction between urine AD7c-NTP and serum 25(OH)D in chronic diseases. Further large-scale studies are needed to validate the results of the present study.

Alzheimer-Associated Neuronal Thread Protein: Research Course and Prospects for the Future.

Alzheimer's disease (AD) is the leading cause of dementia. With aging societies, the prevalence of AD is increasing dramatically worldwide. The onset of AD is often not identified, and currently no available treatments are capable of stopping the disease process and its effect on cognitive decline. Thus, well-validated biomarkers of the preclinical stages of AD are needed. Alzheimer-associated neuronal thread protein (AD7c-NTP) is a member of the neuronal thread protein family and has a molecular weight of approximately 41 kD. AD7c-NTP has been identified as a biomarker for its specifically elevated levels in putative brain domains, cerebrospinal fluid (CSF), and the urine of AD and mild cognitive impairment (MCI) patients. Since the urine test is non-invasive, easy to perform, and patients accept it more easily than other methods, the urinary AD7c-NTP concentration has been recommended as a practical diagnostic tool for diagnosing AD and MCI. AD7c-NTP has undergone nearly 25 years of research course from its initial discovery to pathological verification, multi-center clinical evaluation, improvement of detection methods, epidemiological investigation, and combined application with other biomarkers. However, as a fluid biomarker, AD7c-NTP can be detected in urine instead of the traditional biomarker sources-CSF or blood, which has made the use of AD7c-NTP as a biomarker controversial. In this article, we review the research course of AD7c-NTP and suggest directions for future research.

The relationship between urinary Alzheimer-associated neuronal thread protein and blood biochemical indicators in the general population.

Urinary Alzheimer-associated neuronal thread protein (AD7c-NTP) is elevated in early Alzheimer's disease (AD) and mild cognitive impairment, and is considered a biomarker for the early diagnosis of AD. However, it has not yet been investigated whether urinary AD7c-NTP is elevated with increases in blood biochemical indicators related to AD risk factors. We recruited 2180 participants, aged 35-93 years, from communities of four districts in Beijing. Blood biochemical indicators, including blood glucose, blood lipids, renal function, and high-sensitivity C-reactive protein, were measured using routine methods. Urinary AD7c-NTP was detected using an enzyme-linked immunosorbent assay AD7c-NTP kit. In the general population, there were no significant differences in urinary AD7c-NTP levels in subjects with different Mini-Mental State Examination levels or C-reactive protein values. After adjusting for age and sex, there were significant differences in urinary AD7c-NTP levels between different education levels, marital statuses, blood glucose, blood lipids, and kidney function. There was a negative correlation between urinary AD7c-NTP levels and serum creatinine (r = -0.128). There was a positive correlation between urinary AD7c-NTP levels and HbA1c (r = 0.104), insulin (r = 0.101), and triglycerides (r = 0.093). Urinary AD7c-NTP might be useful as a potential indicator to predict AD risk.

Urinary Alzheimer-Associated Neuronal Thread Protein is not Elevated in Patients with Subjective Cognitive Decline and Patients with Depressive State.

Subjective cognitive decline (SCD) is a risk factor for Alzheimer's disease (AD). Urinary Alzheimer-associated neuronal thread protein (AD7c-NTP) has been identified as a biomarker for AD. It was hypothesized that if urinary AD7c-NTP were also elevated in SCD, as it is in prodromal AD (mild cognitive impairment stage), it could be a convenient and efficient clinical biomarker for the early diagnosis of SCD. SCD is often accompanied by a depressive state (DS), and the impact of DS on urinary AD7c-NTP levels remains unknown. A total of 297 right-handed Chinese Han subjects were recruited, including 98 subjects with SCD, 92 patients with DS, and 107 well-matched cognitively normal controls (NC). The levels of AD7c-NTP in urine samples were measured using an enzyme-linked immunosorbent assay AD7c-NTP kit. Our results demonstrated that urinary AD7c-NTP levels in the SCD group (0.7561±0.5657 ng/mL) were not significantly higher than in either the DS (0.7527±0.5607 ng/mL) or NC (0.7214±0.5077 ng/mL) groups. Furthermore, urinary AD7c-NTP levels were not correlated with Hamilton Depression Rating Scale and Hamilton Anxiety Scale scores, but they were negatively associated with Mini-Mental State Examination scores (r = -0.222, p = 0.033) and Montreal Cognitive Assessment-Basic scores (r = -0.207, p = 0.048). Urinary AD7c-NTP level is not elevated in SCD and is unaffected by DS. Urinary AD7c-NTP may therefore not be a good potential biomarker for SCD and DS, although it may become elevated with more severe cognitive decline.

The Distribution of Urinary Alzheimer-Associated Neuronal Thread Protein and Its Association with Common Chronic Diseases in the General Population.

BACKGROUND: Alzheimer-associated neuronal thread protein (AD7c-NTP) has been found to be a biomarker for Alzheimer's disease (AD). OBJECTIVE: The aim of the present study was to investigate the distribution of Alzheimer-associated neuronal thread protein and its relationship to common chronic diseases in the general population. METHODS: Urine samples of 1,805 participants were collected from four districts (Xi Cheng, Fang Shan, Tong Zhou, and Yan Qing) in Beijing. The assessment in this study included a questionnaire that captured participants' demographic information, use of medication and histories of disease, neurological examinations, psychometric evaluations, physical and clinical examinations, and laboratory tests. RESULTS: Urine AD7c-NTP level was increased among the population over 60 years old and females exhibited higher levels than males. These results controlled for other demographic factors such as education levels, employment status, body mass index and current residence. The urine AD7c-NTP levels exhibited no association with non-neurological diseases (0.3346±0.4482 ng/ml), such as hypertension (0.3445±0.4187), stroke (0.3652±0.4010), diabetes (0.3319±0.4371), dyslipidemia (0.3440±0.4314), renal insufficiency (0.3223±0.3909), cancer (0.5055±1.0006), chronic lung disease (0.2911±0.2852), chronic liver disease (0.5579±0.6726), severe depression symptoms (0.5186±0.7040), and mild depression symptoms (0.3669±0.3811). CONCLUSIONS: Cut-off values for urine AD7c-NTP levels for different age groups and genders should be established. AD7c-NTP levels proved relatively stable in the body and were not impacted by demographic factors or common chronic diseases.

Some Methodological Characteristics of Alzheimer-Associated Urine Neuronal Thread Protein Detected by Enzyme-Linked Immunosorbent Assay.

BACKGROUND: Alzheimer-associated neuronal thread protein (AD7c-NTP) has been found to be a candidate biomarker of Alzheimer's disease (AD). OBJECTIVE: To investigate the effects of urine collected time, different preservatives addition, and storage condition on the measurement of urine AD7c-NTP by enzyme-linked immunosorbent assay (ELISA). METHODS: Three hundred urine samples were collected from 20 participants at three time points on five consecutive days. These samples were immediately placed at 4°C and detected within 2 h. The single spot samples of the first day morning were split into eleven duplicate aliquots (a-k) of 1 ml each, (a) without any preservative (untreated), (b) containing boric acid (2 g/L), (c) containing NaHCO3 (5 g/L), (a-c) were detected at six different time points. For the other eight preservative-free samples, (d-g) were stored at -20°C and (h-k) were stored at -70°C, respectively, detected at different time points. All of the results were compared with the baseline urine. RESULTS: The urine AD7c-NTP levels at different time points behaved stably (p > 0.05). Urine samples without any preservative increased over time, and compared with the NaHCO3 addition group, boric acid addition group behaved stably. Samples stored at -20°C and -70°C led to an obviously false positive. CONCLUSIONS: AD7c-NTP can be tested using random urine instead of the first morning urine. If the specimen cannot be tested in time, boric acid appears to be an acceptable preservative with storage at 4°C, freezing is not recommended.

Correlation between apolipoprotein E gene polymorphism and the urine level of Alzheimer-associated neuronal thread protein in patients with Alzheimer's disease and mild cognitive impairment / 中华神经科杂志

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.

The comparison of urine AD7c-NTP levels and olfactory function among three types of dementia patients / 中华老年医学杂志

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.

Development of a Novel Urine Alzheimer-Associated Neuronal Thread Protein ELISA Kit and Its Potential Use in the Diagnosis of Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is an age-related chronic degenerative disease that damages the nervous system. A noninvasive and simple method for early detection of AD is extremely important for the diagnosis and prognosis of AD. Thus, we aimed to develop an enzyme-linked immunosorbent assay (ELISA) kit to detect urine Alzheimer-associated neuronal thread protein (AD7C-NTP), and to evaluate its clinical value for the diagnosis of AD. METHODS: Immunogenic AD7C-NTP peptide fragments were synthesized by the solid-phase method and used for immunizing mice or rabbits to generate anti-AD7C-NTP antibodies. The urine AD7C-NTP ELISA kit was then established; the generated mouse anti-AD7C-NTP antibody was used as a capture antibody, the biotin-labeled rabbit anti-AD7C-NTP antibody was used as a detection antibody, and avidin labeled by horseradish peroxidase was used as a substrate. The first morning urine specimens of 121 AD patients and 118 age-matched controls were collected, and the urine AD7C-NTP levels were detected by the above ELISA kit. RESULTS: Mouse and rabbit anti-AD7C-NTP antibody ELISA titer was found to be 1:8,000 and 1:32,000, respectively. A single band with a relative molecular mass of 41 kDa was found in human brain specimens by Western blot assay, which was identified as AD7C-NTP antibody. The urine AD7C-NTP concentration of the AD patients was higher than that of the age-matched controls, the sensitivity was 89.3% and the specificity was 84.7%. CONCLUSIONS: Our study demonstrated that our newly developed urine AD7C-NTP ELISA kit has suggested potential for diagnosing AD in a Chinese population, suggesting it may be a useful diagnostic kit for detecting early AD.

The level of Alzheimer-associated neuronal thread protein in urine may be an important biomarker of mild cognitive impairment.

Increased levels of Alzheimer-associated neuronal thread protein (AD7c-NTP) are often detected in urine in the early course of Alzheimer's disease (AD), which makes it a promising biomarker for AD. However, whether the concentration of urinary AD7c-NTP is increased in patients with mild cognitive impairment (MCI) remains unclear. The aim of this study was to explore the value of urinary AD7c-NTP to assist in the diagnosis of cognitive impairment by comparing differences in urinary AD7c-NTP among normal controls, MCI patients and AD patients. One hundred and seventy patients from the Xuan wu Hospital, Capital Medical University were divided into three groups according to their clinical diagnosis: an AD group (n=45), an MCI group (n=60) and a normal group (n=65). The Mini Mental State Examination and the Montreal Cognitive Assessment scale were used to screen for the diagnosis of AD and MCI, and patients met the diagnostic criteria of the National Institute of Neurological Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association. The level of urinary AD7c-NTP was determined using the enzyme-linked immunosorbent assay method. The urinary levels of AD7c-NTP in the AD group (median 2.14 [range 0.49-6.39] ng/ml) and the MCI group (median 1.57 [range 0.4-4.15] ng/ml) were significantly higher than those of the normal group (median 0.53 [range 0.04-2.07] ng/ml). To our knowledge our study is the first to show that the level of urinary AD7c-NTP in MCI patients is higher than in healthy people, which suggests that the level of urinary AD7c-NTP may be an important biomarker for early diagnosis of MCI.

Alzheimer-associated urine neuronal thread protein level increases with age in a healthy Chinese population.

Alzheimer-associated neuronal thread protein (AD7c-NTP) has been found to be a biomarker for Alzheimer's disease (AD) with elevated levels in the cerebrospinal fluid and urine from AD patients in the early stage of the disease. Whether the urine level of AD7c-NTP in healthy people is age-related is still unclear. We aimed to measure the level of urine AD7c-NTP in a healthy Chinese population of different ages. Urine samples of 294 subjects were collected from the Department of Health Examination Center at Xuanwu Hospital of Capital Medical University, China. The samples were divided into five groups by age: Group 1 (20-29 years), Group 2 (30-39 years), Group 3 (40-49 years), Group 4 (50-59 years) and Group 5 (⩾ 60 years). The Mini Mental State Examination and Montreal Cognitive Assessment were carried out. The level of AD7c-NTP in the urine specimen was detected by enzyme-linked immunosorbent assay. The urine AD7c-NTP levels in Group 1, 2, 3, 4 and 5 were 0.3012 ± 0.2373, 0.3702 ± 0.2422, 0.3914 ± 0.2442, 0.4844 ± 0.2908 and 0.5880 ± 0.2638 ng/ml (mean ± standard error of the mean), respectively. The urine AD7c-NTP levels among the five groups differed significantly (F=6.181, p=0.00). Females had a higher urine AD7c-NTP content than males, and the urine AD7c-NTP level increased with age (r=0.28, p=0.00). To our knowledge this study is the first to show that urine AD7c-NTP level increases with age in a healthy Chinese population without cognitive dysfunction. This study suggests that different cut-off values aimed at different age groups should be established for diagnosing cognitive impairments in clinical practice.