Monday, December 26, 2016
Vancouver researcher believes saliva test the wave of the future in Alzheimer's diagnosis and prediction
Dr. Pat McGeer, shown in his UBC lab, believes a simple saliva test may one day help people know whether they are at risk of Alzheimer's disease so they can take preventive measures. RIC ERNST / VANCOUVER SUN
A Vancouver biotech company says it has developed a simple way to help diagnose and predict the risk of Alzheimer’s disease by measuring proteins in saliva associated with the memory-robbing illness.
Dr. Pat McGeer, an 88-year old UBC professor emeritus and former B.C. cabinet minister who’s now CEO of Aurin Biotech, said his recently published research in the Journal of Alzheimer’s Disease shows that the test is an easy way to identify individuals with the disease, or at risk of it, because they have higher concentrations of a protein called amyloid beta protein 42 (AB42). The protein circulates through the body, but in the brain, it causes inflammation and sticky plaques leading to brain shrinkage.
While McGeer has filed a patent on the method his research team developed to preserve saliva after it’s collected, he hopes other laboratories replicate his study and commercialize a test at low cost to consumers. McGeer, who believes Alzheimer’s can be prevented through diet, anti-inflammatories and physical activity, even among those genetically predisposed, says since there are no effective treatments for Alzheimer’s, individuals could take preventive measures if they learn they have high concentrations of the AB42 in their spit sample.
“The number of cases studied (37) is small, but our results are so remarkable, we felt they should be made widely available,” said McGeer, referring to the study in mostly local volunteers. McGeer’s lab made the test kits and delivered them to study participants aged 16 to 92 who provided about a teaspoon of saliva which was collected in vials. Of the study subjects, 27 did not have AD, seven had AD, two had early-stage disease, and one had a form of senility.
Six Alzheimer’s study participants had AB42 measurements more than twice as high (41.58 to 75.20 picograms per ml) as healthy participants. A 51-year-old individual who was cognitively normal but destined to develop Alzheimer’s because of genetic mutations, had a value of 60.90, slightly higher than the average for Alzheimer’s cases. Two other individuals, aged 52 and 60, who were also cognitively normal but at high risk for developing the disease because of family histories (mothers and other relatives), had values of 47.96 and 59.57 picograms per ml.
McGeer said brain deposits of AB42 develop at least a decade before symptoms of the disease appear, so individuals who take the test can learn if they are destined to develop it and then adopt lifestyle and behavioural preventive measures.
“That includes taking over-the-counter non-steroidal anti-inflammatory drugs such as ibuprofen, drinking coffee, and sticking to a Mediterranean diet,” he said.
“Such a regimen can dramatically spare individual’s from Alzheimer disease if commenced well before the age of onset. It is remarkable that while AB42 is made at a constant rate by every organ of the body, it is the brain, and only the brain, which decompensates late in life,” he added.
There is no definitive scientific evidence about what can prevent Alzheimer’s disease but experts repeatedly suggest that a healthy lifestyle appears to be helpful.
Dr. Howard Chertkow, a neurologist at the Jewish General Hospital in Montreal and Scientific Director of the research-driven Canadian Consortium on Neurodegeneration in Aging (CCNA), said he’s familiar with the concept of the test but not the latest findings. He has a few reservations about it.
“Amyloid may not be the whole story in Alzheimer disease. There are individuals with amyloid in their brain who survive into their 90s and do not develop dementia. So a test for amyloid is far from equivalent to having an Alzheimer disease test. However, the presence of abnormal amyloid in an individual with memory problems, increases the likelihood that this is Alzheimer disease.
“Secondly, the numbers reported by Dr. McGeer are, of course, small and further larger samples are required to show that the test is indeed sensitive and specific, replicable, and reliable. However, if this is indeed shown, then a salivary test for amyloid would indeed be a major step forward in developing a biomarker for Alzheimer disease.”
Dr. Howard Feldman, a former University of B.C. Alzheimer’s expert who is now dean of Alzheimer’s disease and neurodegenerative research at the University of California in San Diego, agreed that McGeer’s work on the biomarker test is in a preliminary stage and a bigger study is required to fully validate the test.
“Scientists have been interested in this since 2010 when it was observed that there was higher amyloid in saliva in Alzheimer disease (patients) than controls.
Story Source: The above story is based on materials provided by VANCOUVERSUN
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