When it comes to Alzheimer's disease, there hasn't been much to celebrate in recent years. Efforts to develop a vaccine against the brain disorder have stalled, and no drugs have been able to reverse the slow death of neurons that robs people of their memories and thoughts. For the first time in many years, however, researchers in the field are genuinely excited about the potential for effective drug treatments and helpful new risk factors.
Scientists gathered this week at the Alzheimer's Association's International Conference on Alzheimer's Disease in Chicago, presenting a slew of promising results from drug trials, a new understanding of how the neurological disease works and insights into the way social and lifestyle factors may affect its progression. "On the one hand, Alzheimer's disease is a complex pathologic process, and that is daunting," says Dr. Ronald Petersen, chair of the Alzheimer's Association's medical and scientific advisory council and director of the Mayo Clinic Alzheimer's Disease Research Center. "But now we are beginning to segregate out different therapeutic targets and develop drugs that have an impact on each target, so in combination they may handle the disease better than any single approach."
The potential success of the combination strategy was borne out in some of the conference's most exciting papers. Researchers from Mount Sinai School of Medicine reported, for example, that compared with other Alzheimer's patients, those who had diabetes and took insulin plus another anti-diabetes medication to control blood sugar had 80% fewer amyloid plaques the sticky brain-clogging masses that, together with protein tangles, are the hallmarks of Alzheimer's disease. Although the mechanism wasn't entirely clear, researchers think the drugs may work by normalizing the brain's communication network of insulin receptors, which goes awry in the Alzheimer's brain, while clearing away the damaging plaques.
In a separate trial, an experimental drug called rember, developed by a Singapore-based company, also showed some promise in a safety study. Among 321 patients, rember appeared to stall advancement of the disease, degrading the protein tangles that build up in Alzheimer's brains. Potentially, a combination of drug therapies designed to prevent both plaques and tangles may prove effective in slowing the progression of the disease.
But future approaches won't stop with drug treatments. Petersen notes that researchers are also forging ahead with innovative screening tests to identify Alzheimer's patients sooner before too much deterioration occurs in the brain. Better screens could also potentially identify patients by the specific type of brain buildup plaques vs. tangles that is causing them the most severe problems. That kind of triage early on could help doctors target the right patients with the most effective therapies.
Alzheimer's doctors also reported new discoveries about certain lifestyle factors that may accelerate or slow the dementia that often precedes Alzheimer's. Swedish psychologists studied rates of the disease in a sample of 1,449 people over a period of 21 years. They found, as previous research has suggested, that single people have up to twice the risk of developing Alzheimer's as their married counterparts. But what was unexpected was the finding that the reason for a person's singlehood impacts his or her risk. Compared with other singletons, people who were single as a result of divorce or widowing had a three times and six times greater risk, respectively. "This was quite unexpected," says Krister Hakansson, who led the study and is a lecturer in psychology and a Ph.D. candidate at Vaxjo University and the Karolinska Institute. "We established the association, but when it comes to explaining it, we can only speculate at this state."
One reason for the higher risk could be that those who had the cognitive protection and social benefits of a relationship but lost them may be worse off than those who never enjoyed those benefits at all; or perhaps the emotional toll of losing a close partner damages cognitive functions in a way that puts these people at greater risk for dementia and Alzheimer's down the line. Either way, says Hakansson, the results suggest that "if you are looking for interventions to prevent Alzheimer's, one way may be to identify people who have been divorced or widowed, and who haven't adapted or gotten back into the social circle, and give them support with the aim of giving them new structure and social networks in their lives."
As more discoveries are made, researchers hope they'll develop a better understanding of who is most at risk of Alzheimer's disease, how each patient's case is unique, and how best to treat specific patients with the drug and lifestyle changes that will be most effective for them. Taken together, these approaches could one day make the long goodbye of Alzheimer's a thing of the past.