A simple test for early Alzheimer’s disease has come a step closer, as UK scientists announce that certain proteins in blood can predict the onset of dementia in people suffering from mild cognitive impairment.
A partnership between King’s College London and Proteome Sciences, a UK biotechnology company, developed the potential blood test during a 10-year programme funded partly by the charity Alzheimer’s Research UK. The results are published in the journal Alzheimer’s & Dementia.
“There are thousands of proteins in the blood, and this study is the culmination of many years’ work identifying which ones are clinically relevant,” said Abdul Hye of King’s, lead author. “We now have a set of 10 proteins that can predict whether someone with early symptoms of memory loss, or mild cognitive impairment, will develop Alzheimer’s disease within a year, with a high level of accuracy.”
The researchers analysed samples from 1,148 people, of whom 476 already had Alzheimer’s, 220 had mild cognitive impairment and 452 were elderly controls with no symptoms. Their blood was analysed for 26 proteins already shown to be associated with Alzheimer’s. A series of tests, including scans to detect brain shrinkage, then narrowed these down to 10 molecules which predicted with 87 per cent accuracy whether someone with mild impairment would develop Alzheimer’s within a year.
“This research does not mean that a blood test for dementia is just around the corner,” cautioned James Pickett, head of research at the Alzheimer’s Society. “Accuracy would need to be improved before it could be a useful diagnostic test.”
The next step will be to validate the 10-protein test and reduce the risk of misdiagnosis, with much more extensive clinical testing over the next two or three years.
Although the long-term aim is to produce a simple blood test accurate enough for doctors to use in everyday practice, for patients suffering from early memory loss who want to know their prognosis, the diagnostic test is likely to be used first to help recruit people for clinical trials of new Alzheimer’s drugs.
The past three years have seen the failure of several experimental treatments. “They may have failed because the clinical trials were carried out too late in the progression of disease,” said Simon Lovestone, professor of translational neuroscience at Oxford university. “If we could start treatment earlier in the pre-clinical phase, they might be effective.”
Patent rights to the test are shared between King’s and Proteome. The company, based in Cobham, will lead the commercialisation drive. It does not plan to launch an Alzheimer’s diagnostic on its own but will work with global diagnostics companies, said Ian Pike, chief operating officer.
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