Effects of Exercise on Urinary AD7c-NTP (Alzheimer-Associated Neuronal Thread Protein) Levels and Cognitive Function Among Active Korean Elderly: A Randomized Controlled Trial.

Background: Alzheimer-associated neuronal thread protein (AD7c-NTP) has been demonstrated to have high diagnostic accuracy in differentiating Alzheimer's disease (AD) patients from healthy individuals. However, it is yet unclear whether exercise can lower the level of AD7c-NTP in urine among active Korean elderly. Objective: To assess the effect of exercise on AD7c-ntp levels in urine and cognitive function among active Korean elderly. Methods: In total, 40 Korean elderly (≥65 years) were divided into Active Control group (CG, n = 10), Aerobic exercise group (AG, n = 18), and combined Resistance/Aerobic exercise group (RAG, n = 12). A total of 12 weeks of exercise intervention was implemented. At week 0 and 12, cognitive performance (Korean Mini-Mental State Examination, Korean-Color Word Stroop test), grip strength, and body composition (muscle mass and body fat percentage) were measured. Also, a morning urine sample was obtained from each subject. The level of AD7c-NTP was measured using competitive enzyme-linked immunosorbent assay (ELISA). Results: After 12 weeks of exercise intervention, there was a significant difference of AD7c-NTP levels between RAG and CG (p = 0.026), AG and CG (p = 0.032), respectively. Furthermore, the AD7c-NTP levels in urine showed negative correlation with K-MMSE scores (r = -0.390, p = 0.013) and grip strength (r = -0.376, p = 0.017), among all participants after exercise intervention. Conclusions: This is the first study to investigate urine biomarker through exercise intervention. In future stuides, participants who have low cognitive function and low activity levels need to be recruited to observe more significant 'Exercise' effect.

Dry Chemistry-Based Bipolar Electrochemiluminescence Immunoassay Device for Point-of-Care Testing of Alzheimer-Associated Neuronal Thread Protein.

In this study, we developed, for the first time, a novel dry chemistry-based bipolar electrochemiluminescence (ECL) immunoassay device for point-of-care testing (POCT) of Alzheimer-associated neuronal thread protein (AD7c-NTP), where the ECL signals were automatically collected and analyzed after the sample and buffer solutions were manually added onto the immunosensor. The proposed immunoassay device contains an automatic ECL analyzer and a dry chemistry-based ECL immunosensor fabricated with a screen-printed fiber material-based chip and a three-dimensional (3D)-printed shell. Each pad of the fiber material-based chip was premodified with certain reagents for immunoreaction and then assembled to form the ECL immunosensor. The self-enhanced ECL of the Ru(II)-poly-l-lysine complex and the lateral flow fiber material-based chip make the addition of coreactants and repeated flushing unnecessary. Only the sample and buffer solutions are added to the ECL immunosensor, and the process of ECL detection can be completed in about 6 min using the proposed automatic ECL analyzer. Under optimized conditions, the linear detection range for AD7c-NTP was 1 to 104 pg/mL, and the detection limit was 0.15 pg/mL. The proposed ECL immunoassay device had acceptable selectivity, stability, and reproducibility and had been successfully applied to detect AD7c-NTP levels in human urine. In addition, the accurate detection of AD7c-NTP and duplex detection of AD7c-NTP and apolipoprotein E ε4 gene were also validated. It is believed that the proposed ECL immunoassay device may be a candidate for future POCT applications.

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.

Urinary AD7c-NTP Evaluates Cognition Impairment and Differentially Diagnoses AD and MCI.

The AD7c-NTP is a promising biomarker for AD diagnosis. However, the exact urinary AD7c-NTP concentration to differentiate AD from the mild cognitive impairment (MCI) remains inconclusive. We enrolled 98 and 90 clinical defined AD and MCI patients, respectively, and access their cognition impairment with Neuropsychiatric Inventory (NPI) and Mental State Examination (MMSE) along with their urinary AD7c-NTP. We demonstrated that urinary AD7c-NTP level in sequence from high to low was AD, MCI, and healthy groups (P < .01), and the AD7c-NTP was positively and negatively correlated with the NPI and MMSE scores, respectively. Additionally, AD7c-NTP well-matched NPI subscale scores, including agitation, depression, and apathy (P < .05). Importantly, the optimal cut-off AD7c-NTP level to distinguish the AD and MCI was .94 ng/mL (sensitivity 85.71% & specificity 73.91%). Conclusively, urinary AD7c-NTP could be used for cognition impairment evaluation and differentiated diagnosis of AD and MCI.

Urinary and faecal metabolic characteristics in APP/PS1 transgenic mouse model of Alzheimer's disease with and without cognitive decline.

Alzheimer's disease (AD) has been considered to be a systematic metabolic disorder, but little information is available about metabolic changes in the urine and feces. In this study, we investigated urinary and faecal metabolic profiles in amyloid precursor protein/presenilin 1 (APP/PS1) mice at 3 and 9 months of age (3 M and 9 M) and age-matched wild-type (WT) mice by using 1H NMR-based metabolomics, and aimed to explore changes in metabolic pathways during amyloid pathology progression and identify potential metabolite biomarkers at earlier stage of AD. The results show that learning and memory abilities were impaired in APP/PS1 mice relative to WT mice at 9 M, but not at 3 M. However, metabolomics analysis demonstrates that AD disrupted metabolic phenotypes in the urine and feces of APP/PS1 mice at both 3 M and 9 M, including amino acid metabolism, microbial metabolism and energy metabolism. In addition, several potential metabolite biomarkers were identified for discriminating AD and WT mice prior to cognitive decline with the AUC values from 0.755 to 0.971, such as taurine, hippurate, urea and methylamine in the urine as well as alanine, leucine and valine in the feces. Therefore, our results not only confirmed AD as a metabolic disorder, but also contributed to the identification of potential biomarkers at earlier stage of AD.

Relationship between Urinary AD7c-NTP with Cerebral Microbleeds Based on APOE Genotype.

OBJECTIVE: This study was performed to investigate the association between urinary Alzheimer-associated neuronal thread protein (AD7c-NTP) with cerebral microbleeds (CMBs) based on the apolipoprotein E (APOE) genotypes. METHODS: A total of 471 patients with acute cerebral infarction screened by magnetic sensitive imaging were enrolled in this study. Among them, twenty-seven cases of mixed CMBs were excluded. A total of 444 patients were divided into two groups according to the presence or absence of CMBs: CMBs group (n = 92) and noncerebral microbleeds group (nCMBs) (n = 352). Urine AD7c-NTP levels were measured using a human enzyme immunoassay kit. RESULTS: In patients with lobar CMBs, there was an interaction between urine AD7c-NTP levels and APOE genotypes (p = 0.01). In patients with APOE ε3/ε3 allele, the odds ratio of lobar CMBs per standard deviation of urinary AD7c-NTP levels was 0.92 (95% CI: 0.70-1.19). In patients with APOE ε2+ or ε4+ allele, the multivariate-corrected odds ratio of lobar CMBs per standard deviation of urinary AD7c-NTP levels was 2.95 (95% CI: 1.38-6.27). CONCLUSION: A higher level of urinary AD7c-NTP is involved in lobar CMBs, not deep CMBs.

Urinary metabolic phenotyping for Alzheimer's disease.

Finding early disease markers using non-invasive and widely available methods is essential to develop a successful therapy for Alzheimer's Disease. Few studies to date have examined urine, the most readily available biofluid. Here we report the largest study to date using comprehensive metabolic phenotyping platforms (NMR spectroscopy and UHPLC-MS) to probe the urinary metabolome in-depth in people with Alzheimer's Disease and Mild Cognitive Impairment. Feature reduction was performed using metabolomic Quantitative Trait Loci, resulting in the list of metabolites associated with the genetic variants. This approach helps accuracy in identification of disease states and provides a route to a plausible mechanistic link to pathological processes. Using these mQTLs we built a Random Forests model, which not only correctly discriminates between people with Alzheimer's Disease and age-matched controls, but also between individuals with Mild Cognitive Impairment who were later diagnosed with Alzheimer's Disease and those who were not. Further annotation of top-ranking metabolic features nominated by the trained model revealed the involvement of cholesterol-derived metabolites and small-molecules that were linked to Alzheimer's pathology in previous studies.

A Urinary Metabolomics Analysis Based on UPLC-MS and Effects of Moxibustion in APP/PS1 Mice.

OBJECTIVE: Alzheimer's disease (AD) is a common neurodegenerative disorder with the symptoms of cognitive impairment and decreased learning and memory abilities. Metabolomics can reflect the related functional status and physiological and pathological changes in the process of AD. Moxibustion is a unique method in traditional Chinese medicine, which has been used in the treatment and prevention of diseases for thousands of years. METHODS: A total of 32 APP/PS1 mice were randomly divided into the model group, moxibustion group, moxa smoke group and smoke-free moxibustion group (n=8/group), using the random number table method, while eight C57BL/6 mice were used as the control group. The five groups were measured for 20 min/day, 6 days/week, for 4 weeks. After 4 weeks' experiment, all the mice were placed in metabolic cages to collect urine continuously for 24 hours, for UPLC-MS analysis. RESULTS: Principal component analysis (PCA) was used to identify the different metabolites among the five groups, and partial least squares discriminant analysis (PLS-DA) was performed to reveal the effects on the metabolic variance. Sixteen potential biomarkers were identified among the five groups, primarily related to amino acid metabolism, starch metabolism, sucrose metabolism, interconversion of pentose and glucuronate, and aminoacyl biosynthesis. There were 17 differences in the potential metabolites between the control and model groups, involving the metabolism of amino acid, purine, pyrimidine, nicotinic acid and nicotinamide, and biosynthesis of pantothenate and coenzyme A. Fifteen potential biomarkers were identified between the model and moxibustion groups, related to starch metabolism, sucrose metabolism, interconversion of pentose and glucuronate, glyoxylate, dicarboxylate anions and some amino acid metabolism. CONCLUSION: Moxibustion can regulate the metabolism of substance and energy by improving the synthesis and decomposition of carbohydrates and amino acids in APP/PS1 transgenic AD model mice.

A metabolomic study of the urine of rats with Alzheimer's disease and the efficacy of Ding-Zhi-Xiao-Wan on the afflicted rats.

As a well-known traditional Chinese medicine formula, Ding-Zhi-Xiao-Wan has long been used for the routine treatment of Alzheimer's disease. However, the mechanism of Ding-Zhi-Xiao-Wan in treating Alzheimer's disease is unclear. Therefore, a nontargeted metabolomics method based on ultrahigh performance liquid chromatography with quadrupole time-of-flight mass spectrometry has been established to explore the metabolic variations in the urine of Alzheimer's disease rats and investigate the therapeutic mechanism of Ding-Zhi-Xiao-Wan on Alzheimer's disease. To develop a better rat model of Alzheimer's disease, amyloid ß25-35 was injected into the bilateral hippocampus of Sprague-Dawley rats. Multivariate analysis approaches were applied to differentiate the urine components between the four groups. Thereafter, a targeted metabolomics method was used to verify the identified endogenous metabolites and determine the mechanism of action of Ding-Zhi-Xiao-Wan. Altogether, 26 potential biomarkers were found, of which 15 biomarkers (10 of which are potential biomarkers found in nontargeted metabolomics) were identified. The results show that Ding-Zhi-Xiao-Wan mainly affects the pathways of taurine and hypotaurine metabolism, tryptophan metabolism, and phenylalanine metabolism. Ding-Zhi-Xiao-Wan might play a role in the treatment of Alzheimer's disease by mediating antioxidative stress, regulation of energy metabolism, improvement of intestinal microbes, and protection of nerve cells.

Development of an Immunoassay for the Detection of Amyloid Beta 1-42 and Its Application in Urine Samples.

Amyloid beta peptides (Aß1-42) have been found to be associated with the cause of Alzheimer's disease (AD) and dementia. Currently, methods for detecting Aß1-42 are complicated and expensive. The present study is aimed at developing an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) to detect Aß1-42 by using a polyclonal antibody from alpaca, an application used in urine samples. The serum was collected from the alpaca after immunizing it with Aß1-42 at 500 µg/injection 5 times. The ic-ELISA was developed and showed a half-maximal inhibitory concentration (IC50) of 103.20 ng/ml. The limit of detection (LOD) was 0.39 ng/100 µl. The cross-reactivity was tested with Aß1-40 and 8 synthesized peptides that had sequence similarities to parts of Aß1-42. The cross-reactivity of Aß1-40 and peptide 1 (DAEFRHDSGYE) was 55% and 69.4%, respectively. The ic-ELISA was applied to analyze Aß1-42 in the urine and precipitated protein urine samples. This method can be used for detecting a normal level of total soluble Aß (approximately 1 ng in 5 mg of precipitated urine protein) and can be used for detecting the early stages of AD. It is considered to be an easy and inexpensive method for monitoring and diagnosing AD.

A rapid and non-invasive fluorescence method for quantifying coenzyme Q10 in blood and urine in clinical analysis.

BACKGROUND: Coenzyme Q10 (CoQ10) supplementation can improve cognition in patients with Alzheimer's disease (AD) and AD transgenic model mice. To ameliorate the discomfort that patients with AD suffer after several blood extractions, a non-invasive method for detecting urine CoQ10 levels needs to be established. METHODS: Here, we developed a new technique of fluorescence spectrophotometry with ethyl cyanoacetate (FS-ECA), on the basis of the principle that the chemical derivative obtained from the interaction between CoQ10 and ECA was detected by a fluorescence detector at λex/em  = 450/515 nm. As a standard reference method, the same batches of the clinical samples were analyzed by high-performance liquid chromatography with an ultraviolet detector (HPLC-UV) at 275 nm. RESULTS: The limits of detection (LOD) and limits of quantization (LOQ) (serum: 0.021 and 0.043 mg/L; urine: 0.012 and 0.025 mg/L) determined by the FS-ECA method were similar to that obtained through HPLC-UV (serum: 0.017 and 0.035 mg/L; urine: 0.012 and 0.025 mg/L). More importantly, this new FS-ECA technique as well as the conventional HPLC-UV method could detect a marked difference in urine CoQ10 levels between AD and controls. CONCLUSION: Our findings suggest that this non-invasive method for quantifying urine CoQ10 potentially replaces HPLC to detect blood CoQ10.

Oxidative Damage of DNA as Early Marker of Alzheimer's Disease.

Alzheimer's Disease (AD) is the most common cause of dementia, and its characteristic histopathological hallmarks are neurofibrillary tangles and senile plaques. Among involved mechanisms, oxidative stress plays an important role in damaging cell components (e.g., proteins, nucleic acids). In this study, different oxidized products of proteins and DNA were determined in the urine samples from mild cognitive impairment due to AD patients (n = 53) and healthy controls (n = 27) by means of ultra-performance liquid chromatography-tandem mass spectrometry analysis. A multivariate model developed by partial least squares generated a diagnostic model for AD with an AUC-ROC (area under the curve-receiver operating characteristic) of 0.843. From the studied analytes, 8-OHdG (8-hydroxy-2'-deoxyguanosine) and the ratio 8-OHdG/2dG (2'-deoxyguanosine) were able to distinguish between AD and healthy participants, showing statistically significant differences between groups, postulating DNA oxidation as a molecular pathway involved in early AD.

New screening approach for Alzheimer's disease risk assessment from urine lipid peroxidation compounds.

Alzheimer Disease (AD) standard biological diagnosis is based on expensive or invasive procedures. Recent research has focused on some molecular mechanisms involved since early AD stages, such as lipid peroxidation. Therefore, a non-invasive screening approach based on new lipid peroxidation compounds determination would be very useful. Well-defined early AD patients and healthy participants were recruited. Lipid peroxidation compounds were determined in urine using a validated analytical method based on liquid chromatography coupled to tandem mass spectrometry. Statistical studies consisted of the evaluation of two different linear (Elastic Net) and non-linear (Random Forest) regression models to discriminate between groups of participants. The regression models fitted to the data from some lipid peroxidation biomarkers (isoprostanes, neuroprostanes, prostaglandines, dihomo-isoprostanes) in urine as potential predictors of early AD. These prediction models achieved fair validated area under the receiver operating characteristics (AUC-ROCs > 0.68) and their results corroborated each other since they are based on different analytical principles. A satisfactory early screening approach, using two complementary regression models, has been obtained from urine levels of some lipid peroxidation compounds, indicating the individual probability of suffering from early AD.

Urinary and plasmatic metabolomics strategy to explore the holistic mechanism of lignans in S. chinensis in treating Alzheimer's disease using UPLC-Q-TOF-MS.

Schisandra chinensis (Turcz.) Baill (S. chinensis), a functional food, is used as a tonic and sedative agent in traditional Chinese medicine. Modern pharmacological research has proved that S. chinensis could prevent and treat age-related neurodegenerative diseases. The presence of bioactive lignans in S. chinensis is the main reason for its neuroprotective and cognitive enhancement effects. This study aimed to clarify the mechanism of lignans in S. chinensis in ameliorating learning and memory deficits in Alzheimer's disease (AD) animals. The step-down test and Morris water maze (MWM) test were used to verify the effects of lignans in S. chinensis on learning and memory in AD animals. Then, metabolomics approaches based on ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) were used to clarify the mechanism of lignans in S. chinensis in treating AD. Finally, quantitative analysis of AD-related neurotransmitters in the brain was conducted after treatment with lignans in S. chinensis. In the MWM and step-down tests, lignans in S. chinensis showed a clear ability to ameliorate the impaired learning and memory of AD animals. A total of 31 endogenous metabolites were identified after treatment with lignans in S. chinensis, which were associated with lignans ameliorating learning and memory. These biomarkers were mainly associated with polyunsaturated fatty acid metabolism and amino acid and vitamin metabolism. Moreover, lignans in S. chinensis upregulated the levels of γ-aminobutyric acid (GABA), 5-hydroxytryptamine (5-HT), acetylcholine (Ach), norepinephrine (NE) and glycine (Gly) and downregulate the level of aspartic acid (Asp). Lignans in S. chinensis might alleviate the neurotoxic effects of neurological inflammation and oxidative stress, Aß deposition, and tau phosphorylation via the regulation of multiple endogenous metabolic pathways during pathological AD. The research might provide useful support for the further study of pharmacology and new drug development of lignans in S. chinensis.

Assessment of lipid peroxidation and artificial neural network models in early Alzheimer Disease diagnosis.

OBJECTIVE: Lipid peroxidation constitutes a molecular mechanism involved in early Alzheimer Disease (AD) stages, and artificial neural network (ANN) analysis is a promising non-linear regression model, characterized by its high flexibility and utility in clinical diagnosis. ANN simulates neuron learning procedures and it could provide good diagnostic performances in this complex and heterogeneous disease compared with linear regression analysis. DESIGN AND METHODS: In our study, a new set of lipid peroxidation compounds were determined in urine and plasma samples from patients diagnosed with early Alzheimer Disease (n = 70) and healthy controls (n = 26) by means of ultra-performance liquid chromatography coupled with tandem mass-spectrometry. Then, a model based on ANN was developed to classify groups of participants. RESULTS: The diagnostic performances obtained using an ANN model for each biological matrix were compared with the corresponding linear regression model based on partial least squares (PLS), and with the non-linear (radial and polynomial) support vector machine (SVM) models. Better accuracy, in terms of receiver operating characteristic-area under curve (ROC-AUC), was obtained for the ANN models (ROC-AUC 0.882 in plasma and 0.839 in urine) than for PLS and SVM models. CONCLUSION: Lipid peroxidation and ANN constitute a useful approach to establish a reliable diagnosis when the prognosis is complex, multidimensional and non-linear.

A validated LC-MS/MS method for the determination of homocysteic acid in biological samples.

The role of homocysteic acid (HCA) in severe diseases like Alzheimer's disease is under discussion and some recent studies correlate elevated HCA concentrations with the diagnosis of Alzheimer's. However, non-selective and insufficiently sensitive methods have been used to quantitate HCA and results of different studies show large differences in the determined HCA concentration in samples from patients and controls, and therefore non-comparable results. An accurate and precise quantitation method for the determination of HCA in human serum, urine and CSF has been developed by using a combination of protein precipitation and solid phase extraction for sample preparation followed by an LC-MS/MS analysis using a combination of a HILIC separation and tandem mass spectrometry. The developed method has been fully validated in accordance with the guidelines provided by the US Food and Drug administration FDA and the European Medicines Agency EMA. Furthermore, the method has demonstrated its ability to determine the endogenous HCA concentration in serum and urine samples from healthy volunteers.

Proteomic analysis of urinary extracellular vesicles reveal biomarkers for neurologic disease.

BACKGROUND: Extracellular vesicles (EVs) harbor thousands of proteins that hold promise for biomarker development. Usually difficult to purify, EVs in urine are relatively easily obtained and have demonstrated efficacy for kidney disease prediction. Herein, we further characterize the proteome of urinary EVs to explore the potential for biomarkers unrelated to kidney dysfunction, focusing on Parkinson's disease (PD). METHODS: Using a quantitative mass spectrometry approach, we measured urinary EV proteins from a discovery cohort of 50 subjects. EVs in urine were classified into subgroups and EV proteins were ranked by abundance and variability over time. Enriched pathways and ontologies in stable EV proteins were identified and proteins that predict PD were further measured in a cohort of 108 subjects. FINDINGS: Hundreds of commonly expressed urinary EV proteins with stable expression over time were distinguished from proteins with high variability. Bioinformatic analyses reveal a striking enrichment of endolysosomal proteins linked to Parkinson's, Alzheimer's, and Huntington's disease. Tissue and biofluid enrichment analyses show broad representation of EVs from across the body without bias towards kidney or urine proteins. Among the proteins linked to neurological diseases, SNAP23 and calbindin were the most elevated in PD cases with 86% prediction success for disease diagnosis in the discovery cohort and 76% prediction success in the replication cohort. INTERPRETATION: Urinary EVs are an underutilized but highly accessible resource for biomarker discovery with particular promise for neurological diseases like PD.

Pharmacodynamic and urinary metabolomics studies on the mechanism of Schisandra polysaccharide in the treatment of Alzheimer's disease.

Schisandra chinensis (Turcz.) Baill is produced mainly in northeast China, Korea and Japan. Its fruit has been used in food as a nutritional and functional ingredient for centuries. Polysaccharide is an important chemical component in Schisandra. Previous studies have shown that Schisandra polysaccharide (SCP) could be used to improve cognitive function clinically and treat age-related neurodegenerative disorders. In this study, a urinary metabolomics method based on ultra-high-performance liquid chromatography combined with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) was established to investigate the change of endogenous metabolites in an amyloid ß-protein (Aß) 25-35-induced Alzheimer's disease (AD) rat model. Meanwhile, levels of 9 neurotransmitters were evaluated with ultrahigh-performance liquid chromatography-triple-quadrupole mass spectrometry (UHPLC-TQ-MS) to explore the therapeutic mechanisms of SCP on the AD rat model. Additionally, the synthesis of phosphorylated tau protein (p-tau), acetylcholinesterase (AchE) activity and oxidative damage in the brain of the AD rats were assessed using glycogen synthase kinase-3ß (GSK3ß), AchE and antioxidant assays, NOS (nitric oxide synthase) and SOD (superoxide dismutase), respectively. The results indicated that the AD model was established successfully and the inducement of Aß25-35 caused the phosphorylation of tau protein and the deposition of Aß. In the AD model rats, the levels of AchE, GSK-3ß and NOS were significantly elevated and SOD activity was reduced. In the hippocampus of the model rats, the contents of γ-aminobutyric acid, acetylcholine, glycine, norepinephrine, taurine, serotonin and dopamine were significantly decreased and the contents of glutamate and aspartic acid were increased significantly. However, SCP could reduce the degree of phosphorylation of tau protein, the deposition of Aß and oxidative damage and reverse these changes of neurotransmitters in the AD rats. In a metabolomics study, a total of 38 metabolites were finally identified as potential biomarkers of AD and all of them had a significant recovery compared with the AD model after SCP administration. Metabolomics studies have shown that SCP plays a role in protecting the central nervous system, regulating intestinal microbial metabolism, regulating energy metabolism, and promoting antioxidant effects by regulating the levels of endogenous metabolites in related pathways. This is first report of the use of urine metabolomics combined with the evaluation of 9 neurotransmitter levels to investigate the mechanism of SCP on the treatment of AD.

A rapid and sensitive fluorescence method for detecting urine formaldehyde in patients with Alzheimer's disease.

BACKGROUND: Morning urine formaldehyde concentrations could predict the severe degree of dementia in patients with post-stroke dementia and Alzheimer's disease. However, the routinely available technique of high-performance liquid chromatography (HPLC) for detecting urine formaldehyde requires expensive and sophisticated equipment. METHODS: We established a fluorescence spectrophotometric method by using a formaldehyde-specific fluorescent probe-NaFA (λex/em = 430/543 nm). As a standard reference method, the same batch of urine samples was analysed by HPLC with a fluorescence detector (λex/em = 346/422 nm). Then we compared the limits of detection and the limits of quantization detected by these two methods and addressed the relationship between urine formaldehyde and human cognitive ability. The Mini-Mental State Examination (MMSE), Clinical Dementia Rating and Activities of Daily Living scale were used to evaluate cognition function in 30 Alzheimer's disease patients and 52 healthy age-matched controls. RESULTS: Limits of detection and limits of quantization (1.27 and 2.48 µM) of the NaFA probe method were more accurate than Fluo-HPLC (1.52 and 2.91 µM). There was no difference in the detected formaldehyde values within day and day-to-day. Notably, only 3/82 urine formaldehyde concentrations detected by NaFA probe were below zero, while 12/82 of the values analysed by Fluo-HPLC were abnormal. More importantly, there were negatively correlated between urine formaldehyde concentrations detected by NaFA probe and MMSE scores, but positively correlated with Clinical Dementia Rating scores in Alzheimer's disease patients. CONCLUSIONS: This detecting urine formaldehyde method by NaFA probe was more rapid, sensitive and accurate than Fluo-HPLC.

A Pilot Study of Urinary Exosomes in Alzheimer's Disease.

BACKGROUND: Exosomes are nano-sized extracellular vesicles secreted by most cell types and abundantly present in body fluids, including blood, saliva, urine, cerebrospinal fluid, and breast milk. Exosomes can spread toxic amyloid-beta (Aß) and hyperphosphorylated tau between cells, contributing to neuronal loss in Alzheimer's disease (AD). OBJECTIVE: To explore changes in the morphology, number, and pathological protein levels of urinary exosomes in AD patients compared with age-matched healthy subjects. METHODS: In this study, enzyme-linked immunosorbent assay was used to detect the levels of Aß1-42 and P-S396-tau (normalized by CD63) in urinary exosomes of AD patients and matched healthy subjects. We used transmission electron microscopy and nanoparticle tracking analysis to observe the exosomes. RESULTS: We found that the levels of Aß1-42 and P-S396-tau in the urinary exosomes of AD patients were higher than those of matched healthy controls. Exosomes taken from AD patients were more numerous. CONCLUSION: The differences in levels of Aß1-42 and P-S396-tau and the quantity of urinary exosomes between AD patients and healthy controls may provide a basis for early diagnosis of AD.