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Proteome Sciences has developed a novel biomarker panel for simultaneous measurement of 9 protein markers in Alzheimer Disease patient plasma samples, delivering absolute quantitation of endogenous protein levels. The Alzheimer’s Plasma 9-plex Assay is initially intended for use in patient stratification for clinical trials and for basic research in Alzheimer’s Disease. Analysis of plasma samples provides substantial benefits over historically used Cerebrospinal Fluid (CSF) samples, and permits easier routine sample collection and analysis from a greater number of patients.
 

Applications	Sample Types	Species	Analysis Method
Alzheimer's drug discovery	Plasma Samples	Human	TMT-SRM Peptide Mass  Spectrometry
*Alzheimer's clinical analysis; early detection/prognostic	*Plasma Samples	Human	TMT-SRM Peptide Mass Spectrometry

 

* Coming soon – please enquire
 

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The Alzheimer’s Plasma 9-plex Assay uses a highly reproducible and sensitive Selected Reaction Monitoring (SRM) mass spectrometry method coupled with heavy isotope-doped labeled peptide reference standards. Both sample proteins and reference peptides are labeled with Proteome Sciences’ proprietary Tandem Mass Tags^® (TMT^®s) prior to analysis. Learn more…
 

 

• Off-the-shelf Mass Spectrometry assay service available through ISO 9001:2008 accredited facility
• Focused panel of biomarkers for early diagnosis and/or prognostic monitoring of AD
• Unique proprietary panel of biomarkers (patents issued & pending)
• Accurate, precise and reproducible results
• HPLC sample fractionation for highest degree of purity & sensitivity
• Physiological range covered for all 9 protein biomarkers

  

In addition to the Alzheimer’s Plasma 9-plex Assay being used in patient stratification for clinical trials for Alzheimer’s Disease therapeutics and for basic research, it’s anticipated that the panel may eventually be used in the clinical management of patients with confirmed or suspected Alzheimer’s Disease. The nine proteins contained within the panel were selected from a larger list of over 30 candidate markers identified using a range of proteomic profiling methods and which have been replicated in follow-on studies conducted by Proteome Sciences and our collaborative partners at King’s College London, and additional independent studies.

Among current proposed methods for patient stratification and monitoring in AD, the most widely accepted is monitoring CSF levels of amyloid beta peptides 1-40 and 1-42, total tau protein and tau phosphorylated at threonine 181. However, it is widely recognized that CSF collection is not appropriate for widespread use or in routine clinical medicine. Consequently, several AD-specific plasma markers have been proposed, some of which are included in wider general CNS ‘discovery’ panels that are currently used for clinical applications. 
 

Alternate methods rely on brain imaging using MRI or CT Scans. However, there is a perceived high level of subjectivity in interpreting the image data, which has so far led the FDA not to endorse these methods for clinical applications. In peer-reviewed studies changes in plasma levels of Proteome Sciences’ proprietary biomarkers have been shown to be in accordance with imaging data such as hippocampal atrophy and general brain volumetry, as well as in functional MRI measures of neuronal activity.

Proteome Sciences has developed a mass spectrometry method using Selected Reaction Monitoring (SRM) to measure all nine proteins simultaneously from a starting volume of around 2 microlitres of human plasma. The method employs 11 heavy isotope-doped reference peptides covering the nine target proteins. External 11-point calibration curves are prepared using the heavy peptides in normal plasma, which allow for any matrix effect. A single internal reference value for each of the 11 peptides is added to each sample at a concentration roughly equivalent to the normal plasma concentration of the target protein. Consequently the result delivers an absolute quantitation of the endogenous protein levels.

Both the heavy isotope-doped reference peptides and each patient sample are independently labeled using Proteome’s proprietary isotopic Tandem Mass Tags^®. In total, sample preparation, labeling and analysis takes around 24 hours, which is standard for an SRM method. Day to day assay performance has been shown to yield high precision and low CV’s well within accepted levels.

A performance evaluation study comparing Proteome Sciences’ SRM mass spectrometry method and a commonly used bead based immunoassay technology platform is currently ongoing in a trial of 1000 human patient plasma samples with results expected in early 2012.