2 New Studies Offer Clues About Development of Alzheimer's
The news today is exciting! A new study just published in Nature has provided the strongest evidence that an excessive amount of beta amyloid, which is a common brain substance, is behind the disease.
This study, which is out of Iceland’s deCODE Genetics, involved studying the DNA genomes of approximately 1,800 Icelandic people. “About 1 in 100 had a mutation in the gene for a large protein that is sliced to form beta amyloid,” the New York Times reported. “Then the investigators studied people ages 85 and older and people who had been given an Alzheimer’s diagnosis. Those with the mutation appeared to be protected from Alzheimer’s disease.” In fact, this mutation seems to slow the production of beta amyloid by as much as 40 percent.
The researchers also reviewed the genomes of North Americans where they found that only one in 10,000 people have the protective gene mutation. This finding caused researchers to believe that the mutation happened in Scandinavia relatively recently.
Furthermore, the researchers found that the protective mutant gene may take over even in people who have two copies of the ApoE4 gene, which is considered a strong risk factor for Alzheimer’s. The New York Times notes that ninety percent of people who have two copies of the ApoE4 genes get Alzheimer’s by the time they are 80 years of age. However, in the Iceland study, 25 participants were found to have two copies of ApoE4 gene; none of those has Alzheimer’s disease.
The study follows in the heels of another one earlier this week that found that brain changes occur 25 years before memory and cognitive problems emerge. This study, which was out of Washington University and was published in the New England Journal of Medicine, provides a timeline of the changes that happen in spinal fluid, brain size, brain plaques and other factors in the run-up to Alzheimer’s disease in people who are genetically predisposed to the disease. The study focused on people enrolled in the Dominantly Inherited Alzheimer’s Network. This consortium enrolls people who are genetically predisposed to get the disease at an early age (on average by the age of 45), the Huffington Post reported.
In this study, researchers followed 129 participants, using family histories to estimate when they may begin to develop Alzheimer’s symptoms. They found that the first of these changes, which was a drop in the level of amyloid protein, can be seen in spinal fluid as early as 25 years before the disease is expected to develop. The researchers also saw clumps of an Alzheimer’s-related protein on brain scans at 15 years before the onset of the disease. They determined that the brain has difficulty processing glucose, causing difficulty in memory skills 10 years before the disease emerges.
So what do these studies mean? The answer is drug development. Pharmaceutical companies are continuing to try to find ways to stop these plaques from forming and the Washington State study provides a good timeline for when trials should begin administering drugs. And the Iceland study helps researchers know that they’re on the right track. One New York Times story quoted Dr. Richard Mohs, who leads neuroscience early clinical development at Eli Lilly, as saying that the company was “very encouraged by these study results” and believed that focusing on creating drugs that target beta amyloid levels is “a logical path for the development of effective therapies that may slow disease progression.” Unfortunately, it will take time. CNN noted that it probably will take at least four years for drugs under development start to show results.
Primary Resources for This Sharepost:
CNN. (2012). Rare genetic mutation protects against Alzheimer’s.
Huffington Post. (2012). Alzheimer’s brain changes occur 25 years before memory problems: Study.
Kolata, G. (2012). In preventing Alzheimer’s, mutation may aid drug quest.
New York Times. (2012). Protective mutant gene may aid Alzheimer’s fight. In Houston Chronicle.