Fluid Of Alzheimer's Disease Patients Research Articles

Recognition of Alzheimer’s Disease Related miRNAs Based on Genome-Wide Association Study Data

To analyze the mi RNA expression profile of patients with Alzheimer's disease (AD) in order to intensively study the relationship between mi RNA and the occurrence and development of AD, and to lay the foundations for the finding of new molecular markers. Use mi RNA chip to detect the mi RNA expression profiles of cerebrospinal fluid in AD patients and elderly people with normal cognition, and perform preliminary bioinformatics analysis. Real-time PCR was used to verify the results of mi RNA chip detection. The results of mi RNA chip analysis showed that there were many differentially expressed mi RNA in cerebrospinal fluid of AD patients and elderly people with normal cognition. Cerebrospinal fluid in AD patients has a specific mi RNA expression profile, suggesting that a new molecular marker for AD may be found in the expression of mi RNA.

The Brain Injury Biomarker VLP-1 Is Increased in the Cerebrospinal Fluid of Alzheimer Disease Patients

Definitive diagnosis of Alzheimer disease (AD) can be made only by histopathological examination of brain tissue, prompting the search for premortem disease biomarkers. We sought to determine if the novel brain injury biomarker, visinin-like protein 1 (VLP-1), is altered in the CSF of AD patients compared with controls, and to compare its values to the other well-studied CSF biomarkers 42-amino acid amyloid-beta peptide (Abeta(1-42)), total Tau (tTau), and hyperphosphorylated Tau (pTau). Using ELISA, we measured concentrations of Abeta(1-42), tTau, pTau, and VLP-1 in CSF samples from 33 AD patients and 24 controls. We compared the diagnostic performance of these biomarkers using ROC curves. CSF VLP-1 concentrations were significantly higher in AD patients [median (interquartile range) 365 (166) ng/L] compared with controls [244 (142.5) ng/L]. Although the diagnostic performance of VLP-1 alone was comparable to that of Abeta, tTau, or pTau alone, the combination of the 4 biomarkers demonstrated better performance than each individually. VLP-1 concentrations were higher in AD subjects with APOE epsilon4/epsilon4 genotype [599 (240) ng/L] compared with epsilon3/epsilon4 [376 (127) ng/L] and epsilon3/epsilon3 [280 (115.5) ng/L] genotypes. Furthermore, VLP-1 values demonstrated a high degree of correlation with pTau (r = 0.809) and tTau (r = 0.635) but not Abeta(1-42) (r = -0.233). VLP-1 was the only biomarker that correlated with MMSE score (r = -0.384, P = 0.030). These results suggest that neuronal injury markers such as VLP-1 may have utility as biomarkers for AD.

Immunoassay for Serum Glutamine Synthetase in Serum: Development, Reference Values, and Preliminary Study in Dementias

Glutamine synthetase (GS) is a ubiquitous enzyme present at high concentrations in liver, muscle, kidney, and brain (1). GS in the brain is astrocyte specific, is involved in the detoxification of ammonia and glutamate, and is overexpressed after brain injury (2). Monomeric GS protein was found in 38 of 39 cerebrospinal fluid samples obtained from Alzheimer disease (AD) patients (3), and the concentration of GS in the lumbar cerebral spinal fluid of AD patients was increased significantly but nonspecifically (4). GS has also been reported in serum (4). Markers for AD have poor sensitivity and specificity for overt or preclinical AD (5)(6). We have developed an ELISA that is rapid, highly sensitive, and GS specific. This ELISA, together with the S100B and neuron-specific enolase (NSE) ELISAs, was used to retrospectively assess serum GS in healthy controls, AD patients, and other dementia patients. Recombinant human GS (rhGS) cDNA was purchased from ATCC (ATCC No. 409071). The full-length rhGS open reading frame was obtained by PCR and subcloning in pET28a ( Nde l/ Xho I). The construct included a polyhistidine tag at the N-terminal domain of the rhGS open reading frame and no extra sequence at the C-terminal domains. The protein was expressed in E. coli BL21 (DE3) (7). We prepared extracts and solubilized products as described (8). Affinity purification was performed by nickel-nitrilotriacetic acid chromatography. Female Balb/c mice (7–8 weeks of age) were immunized by subcutaneous injection of 50 μg of rhGS emulsified in complete Freund’s adjuvant. An intraperitoneal booster injection was given 3 weeks later (50 μg in incomplete Freund’s adjuvant) and then at 2- to 3-week intervals (three times or more) with a final injection of 50 μg of antigen in buffer via intraperitoneal route 3 days before cell fusion. Hybridoma cultures were screened by ELISA, and …

Elevated levels of phosphorylated neurofilament proteins in cerebrospinal fluid of Alzheimer disease patients

Neurofilament (NF) subunits NF-H, NF-M and NF-L are hyperphosphorylated and elevated in Alzheimer disease (AD) brain. We investigated the level and phosphorylation states of NF subunits in lumbar cerebrospinal fluid (CSF) from living patients by bienzyme substrate-recycle enzyme-linked immunosorbent assay. We found: (i), that the levels of phosphorylated NF-H/M (pNF-H/M), non-phosphorylated NF-H/M (npNF-H/M) and NF-L were significantly higher (pNF-H/M, ∼12–24-fold; npNF-H/M, ∼3–4-fold) in neurologically healthy aged people than young control individuals; (ii), that in AD, the levels of npNF-H/M, and NF-L were similar to vascular dementia (VaD), and higher than in age-matched controls; and (iii), that the levels of pNF-H/M were significantly higher than in aged controls, non-AD neurological disorders and VaD. Based on these findings, it is suggested that the increased level of total NF proteins in CSF could be used as a marker for brain aging and neurodegenerative disorders in general, and the levels of pNF-H/M as a marker to discriminate AD from normal brain aging and as well as neurological conditions including VaD.

Reduced Levels of Cholesterol, Phospholipids, and Fatty Acids in Cerebrospinal Fluid of Alzheimer Disease Patients Are Not Related to Apolipoprotein E4

Apolipoprotein E4 (apoE4) has been identified as a major risk factor for Alzheimer disease (AD). Previously it has been reported that levels of apoE are reduced in cerebrospinal fluid (CSF) of AD patients. Because it is known that apoE4 affects plasma lipid metabolism, we examined whether the presence of apoE4 might correlate with an altered lipid metabolism in the CSF of control subjects and AD patients. ApoE and lipid concentrations were determined in postmortem ventricular CSF of 30 neuropathologically confirmed AD cases and 31 age-matched control patients. ApoE genotyping was performed on frozen brain tissue of the same patients. In line with other reports, we found an increased APOE*4 allele frequency in the AD group (0.461) when compared with the control group (0.225). ApoE levels in CSF of AD patients were not significantly reduced when compared with the controls (mean +/-SD: 63+/-55 and 82+/-62 microg/dL for AD and controls, respectively). However, in the CSF of AD patients levels of free and esterified cholesterol (0.13+/-0.09 and 0.25+/-0.19 mg/dL, and 0.25+/-0.19 and 0.42+/-0.34, respectively), phospholipids (0.2+/-0.1 and 3.5+/-5.0 mg/dL) and, suprisingly, also fatty acids (4.5+/-3.2 and 28.0+/-18.5 micromol/L) were found to be significantly reduced. After correction for age, sex, postmortem delay, and pH the levels of phospholipids, fatty acids, and free cholesterol were still significantly reduced (p = 0.021, p = 0.026, andp = 0.012, respectively). The apoE and lipid levels in CSF of AD-and control patients appeared not to be affected by the number of APOE*4 alleles. In conclusion, our results suggest an altered lipid homeostasis in the brain of AD patients that is not related to the presence of apoE4. It is, therefore, unlikely that an effect of apoE4 on brain lipid metabolism is the underlying mechanism behind the role of apoE4 in the development of AD.