The global Alzheimer's Association round robin study on plasma amyloid β methods.

Introduction: Blood-based assays to measure brain amyloid beta (Aβ) deposition are an attractive alternative to the cerebrospinal fluid (CSF)-based assays currently used in clinical settings. In this study, we examined different blood-based assays to measure Aβ and how they compare among centers and assays.

Methods: Aliquots from 81 plasma samples were distributed to 10 participating centers.

Investigation of the Number of Tests Required for Assaying Plasma Biomarkers Associated with Alzheimer's Disease Using Immunomagnetic Reduction.

Introduction: Concentrations of plasma biomarkers associated with Alzheimer's disease have been reported to be as low as several tens of picograms/milliliter (pg/ml). However, in assays measuring these biomarkers, it is likely that repeated measurements are necessary to obtain reliable values.

Methods: We performed assays as a single test or as duplicate, quadruplicate, fivefold and tenfold repeated tests, on samples spiked with different concentrations of amyloid β 1-40 (Aβ; 1-1000 pg/ml), Aβ (1-30,000 pg/ml) and total Tau protein (T-Tau; 0.

Immunomagnetic Reduction Detects Plasma Aβ Levels as a Potential Dominant Indicator Predicting Cognitive Decline.

Although the concentrations of Alzheimer's disease (AD) biomarkers Aβ, Aβ and tau protein are very low in human plasma, ultrasensitive assays such as immunomagnetic reduction (IMR) are able to precisely quantify them. Review articles have described the detailed working mechanism of IMR and revealed the feasibility of detecting early-stage AD by assaying these plasma biomarkers with IMR. In this review, we aimed to compare the significance of these plasma biomarkers in predicting cognitive decline in patients with Down syndrome, stroke, or amnestic mild cognitive impairment based on findings in the literature.

Effect of Times to Blood Processing on the Stability of Blood Proteins Associated with Dementia.

Background: The stability of proteins in the collecting tubes after blood draw is critical to the measured concentrations of the proteins. Although the guidelines issued by the Clinical and Laboratory Standards Institute (CLSI) suggest centrifugation should take place within 2 h of drawing blood, it is very difficult to follow these guidelines in hospitals or clinics. It is necessary to study the effect of times to blood processing on the stability of the proteins of interest.

Development of an assay of plasma neurofilament light chain utilizing immunomagnetic reduction technology.

Axonal damage leads to the release of neurofilament light chain (NFL), which enters the CSF or blood. In this work, an assay kit for plasma NFL utilizing immunomagnetic reduction (IMR) was developed. Antibodies against NFL were immobilized on magnetic nanoparticles to develop an IMR NFL kit.

Plasma pyroglutamate-modified amyloid beta differentiates amyloid pathology.

Introduction: Pyroglutamate-modified amyloid β (Aβ) could be a biomarker for Aβ plaque pathology in the brain. An ultra-high-sensitive assay is needed for detecting Aβ.

Methods: Immunomagnetic reduction was used for quantification of Aβ in plasma from 46 participants.

Stability of Plasma Amyloid-β 1-40, Amyloid-β 1-42, and Total Tau Protein over Repeated Freeze/Thaw Cycles.

Introduction: Blood biomarkers of Alzheimer's disease (AD) have attracted much attention of researchers in recent years. In clinical studies, repeated freeze/thaw cycles often occur and may influence the stability of biomarkers. This study aims to investigate the stability of amyloid-β 1-40 (Aβ), amyloid-β 1-42 (Aβ), and total tau protein (T-tau) in plasma over freeze/thaw cycles.

Plasma pS129-α-Synuclein Is a Surrogate Biofluid Marker of Motor Severity and Progression in Parkinson's Disease.

Phosphorylated α-synuclein accounts for more than 90% of α-synuclein found in Lewy bodies of Parkinson's disease (PD). We aimed to examine whether plasma Ser129-phosphorylated α-synuclein (pS129-α-synuclein) is a surrogate marker of PD progression. This prospective study enrolled 170 participants (122 PD patients, 68 controls).

Sodium vanadate combined with L-ascorbic acid delays disease progression, enhances motor performance, and ameliorates muscle atrophy and weakness in mice with spinal muscular atrophy.

Background: Proximal spinal muscular atrophy (SMA), a neurodegenerative disorder that causes infant mortality, has no effective treatment. Sodium vanadate has shown potential for the treatment of SMA; however, vanadate-induced toxicity in vivo remains an obstacle for its clinical application. We evaluated the therapeutic potential of sodium vanadate combined with a vanadium detoxification agent, L-ascorbic acid, in a SMA mouse model.

Decreased stathmin expression ameliorates neuromuscular defects but fails to prolong survival in a mouse model of spinal muscular atrophy.

Spinal muscular atrophy (SMA), a genetic neurodegenerative disorder, is caused by mutations or deletions in the survival of motor neuron 1 (SMN1) gene that result in SMN deficiency. SMN deficiency impairs microtubule networks in Smn-deficient cells and in SMA-like motor neuron cultures. Microtubule defects can be restored by knockdown of the stathmin gene (Stmn), which is upregulated in SMA.

Antioxidant role of human haptoglobin.

Human plasma haptoglobin (Hp) is classified according to three phenotypes: Hp 1-1, 2-1, and 2-2 attributed by their two common alleles 1 and 2. Clinically, the 2-2 phenotype is associated with the risk of cardiovascular diseases and diabetes mellitus in patients. In this study, we demonstrate that Hp is an extremely potent antioxidant, which directly protects low density lipoprotein from Cu(2+)-induced oxidation.