The July 19,2014 Economist reports that tests for Alzheimer’s are improving but treatment is still some way off.
RUG companies have got good at treating bad hearts, livers and lungs. They are still lousy, though, at treating ailing minds. That is troubling. Last year, according to estimates announced on July 15th at the Alzheimer’s Association’s annual conference, in Copenhagen, more than 44m people were suffering from dementia. By 2050 that number is expected to triple.
Drug researchers continue to trudge forward, ever-hopeful of a breakthrough. But some of the most interesting work reported to the meeting concerned not drugs, but tests that screen for the disease-a contentious practice, given that no treatment yet exists. Less controversially, other researchers presented data on habits that seem to delay dementia’s toll.
It used to be that physical evidence of Alzheimer’s disease could be found in the brain only post mortem This is changing. In the past two years American regulators have approved the use of chemicals which bind to beta-amyloid, a sticky protein implicated in the condition. Thanks to these tracers, scans can detect amyloid plaques in the brain of someone who is still alive. Other tests look for the offending proteins in cerebrospinal fluid, obtained from spinal taps. And Keith Johnson of Massachusetts General Hospital reported on scans that detect tangles of tau, another protein involved in the disease. In Dr Johnson’s study, 56 participants who had tau in their entorhinal cortex and temporal neocortex (sections of the brain important to memory) had, over the previous three years, achieved progressively lower scores on a memory test.
Such tests, however, are expensive, so researchers are working to create cheaper, simpler ones-with some success. On July 8th Proteome Sciences, a British company, said it had found ten proteins in the blood that could predict Alzheimer’s. New tests presented in Copenhagen provide further alternatives, searching for dementia in neither the brain nor the blood, but in the eye and the nose.
Shaun Frost of the Commonwealth Scientific and Industrial Research Organisation, in Australia, focused his research on beta-amyloid in the retina. He gave volunteers a supplement containing curcumin, a chemical that binds to beta-amyloid and acts as a fluorescent tag. Dr Frost’s scanner detected the tagged beta-amyloid in the volunteers’ retinas. This correlated closely with amyloid levels in their brains, as revealed by scanning. In a separate presentation, a firm called Cognoptix announced data for its own eye test, detecting amyloid in the eye’s lens. And researchers from Harvard and Columbia universities showed that poor performance on simple smell tests is linked with failing memory.
These tests are promising, but will need more data to confirm their accuracy. A separate, important question is whether, if they do work, they should actually be deployed. Even a perfect test cannot prompt good treatment when no treatment exists. Nevertheless, Maria Carrillo of the Alzheimer’s Association argues that better tests will speed the development of new medicines-patients at the earliest stages of disease might enroll in clinical trials to prevent dementia’s progress. The most recent such endeavour, a collaboration between Novartis, a giant drugs firm, and the Banner Alzheimer’s Institute, in Arizona, was announced on July 15th.
For now, the most promising data for delaying dementia stem not from drug trials but from studies of behaviour. Yonas Geda and his colleagues at the Mayo Clinic told the meeting of new evidence that exercise, especially in middle age, helps preserve the brain’s function and lowers the risk of subsequently developing dementia. And a presentation by Miia Kivipelto of Finland’s National Institute for Health and Welfare was particularly encouraging. More than 1,200 Finns, aged 60-77, took part in a randomised trial of specific interventions. These included treatment of cardiovascular problems, and physical and mental exercises. Compared, after two years, with a control group that received health care as usual, these people scored better on memory and cognitive tests.
Eventually, then, researchers may work out how to treat Alzheimer’s with drugs. In the meantime, the best ways to ward off dementia seem decidedly low-tech.