26-March-2012 - Variability in blood-based amyloid-ß assays: The need for consensus on pre-analytical processing
Associate Professor Kevin Barnham from the Mental Health Research Institute has recently finished a report that highlights both the need for standard blood collection and processing methods in Alzheimer’s disease research, and a way forward.
There is a growing realisation within the field of Alzheimer’s disease, that the notion of treating Alzheimer’s disease within its mild to moderate stages is too late. With underlying neurodegeneration preceding the clinical onset of Alzheimer’s disease by about 20 years, it is recognised that to be effective, therapeutic interventions should be implemented before synaptic loss and neuronal degeneration is largely irreversible.
One very significant implication is that some form of population based screening will need to be undertaken in order to identify those at risk.
Amyloid imaging with positron emission tomography (PET) and cerebrospinal fluid (CSF) levels of the proteins beta-amyloid and tau are currently accepted as the best markers of Alzheimer’s disease however it is questionable as to whether these methods are practical for screening the general population.
In such large scale investigations the use of PET imaging and the specialist requirements of CSF collection would prove to be both logistically and economically impractical, this could easily be overcome if we were able to utilise a more readily accessible biological sample, such as blood.
Preclinical interventions are by no means a novel concept as seen in the diagnosis and treatment of diseases such as cancer, type II diabetes, and atherosclerosis.
With recent estimates suggesting that global prevalence of dementia will rise from approximately 35 million diagnosed cases in 2010 to over 115 million cases by 2050, the only way to identify at risk individuals in the general population is through large-scale testing of individuals within their 50s and early 60s.
The amyloid beta (Aβ) peptide is also found in blood which is the most economical and efficient biological fluid to analyse. Unfortunately, investigations into blood-based diagnostic markers have produced mixed results. This variability is likely to be the result of differences in the processing of samples and is delaying progress in the field.
As Associate Professor Kevin Barnham states “This report represents a vital step towards the establishment of standardised collection protocols for measuring Aβ within human blood and progresses our aim to deal with the increasing need to detect and prevent Alzheimer’s disease in the most economical and effective way”