Blood Antibody Screen May Be Developed to Test for Early Alzheimers Disease
Identifying biomarkers for Alzheimer’s Disease beyond what we already know about brain plaques and tangles will help scientists eventually develop treatments to slowing or curing the devastating memory-robbing disease. So far, those biomarkers known to researchers, specifically amyloid-beta protein and tau proteins, are obtained through the cerebrospinal fluid.
Now researchers at The Scripps Research Institute in Florida believe they may have found that certain antibodies in the blood stream may one day be used to detect Alzheimer’s disease – and possibly some other diseases - early in its progression.
Antibodies are proteins produced by the immune system in response to an antigen, or harmful substance that invades the body. Each type of antibody is unique and defends the body against one specific type of antigen. Identifying the antigen that sets off an immune response may help researchers identify the true trigger or cause of events that lead to brain cell damage.
Thomas Kodadek PhD, a professor of chemistry and cancer biology, compared blood samples from six Alzheimer’s patients, six Parkinson’s disease patients, and six healthy controls in a study funded by the US National Institutes of Health. The researchers screened the blood for antigens using thousands of synthetic molecules called peptoids that would bind with the antibodies.
The researchers found that two of the thousands of molecules were “captured” by the immunoglobulin (IgG) antibodies at least three times more in all of the Alzheimer’s patients than in the Parkinson’s patients or the healthy controls. These two molecules may be candidates for future biomarkers of the disease.
Being able to detect Alzheimer’s via antibiodies would be a simpler and less invasive method of diagnosing the disease, says Kodadek. But, also, while the findings are promising, the results are still preliminary and need to be replicated in larger numbers of patients.
Some have questioned the benefits of diagnosing Alzheimer’s early when there is no current effective treatment for the disease. Kodadek says, “It’s unclear whether people would want to know a couple of years ahead of time that they are going to get Alzheimer’s if they can’t do anything about it, but I can say with some certainty that we will never get a good therapy for Alzheimer’s without early diagnosis.”
Source Reference: "Identification of Candidate IgG Antibody Biomarkers for Alzheimer's Disease through Screening of Synthetic Combinatorial Libraries," by M. Muralidhar Reddy et al., Cell, Jan 7 2011