Simple Alzheimer’s disease test developed

By Dr. Ananya Mandal, MDJan 9 2011

The latest research has shown that a simple blood test could detect Alzheimer’s disease. Applying the same technology it could also detect hard-to-detect cancers and other diseases. The study reports appeared this Thursday in the journal Cell.

The method uses synthetic molecules called peptoids to “fish” for disease-specific antibodies in the blood. Traditionally, the tests work by detecting immune system antibodies that target natural proteins linked to diseases but this principle is just the opposite. These proteins, known as “antigens” may be attached to viruses, bacteria and cancer cells, or be associated with brain diseases such as Alzheimer’s and Parkinson’s. Using this technique there is a substitution of artificial peptoids for antigens. Peptoids that attract antibodies associated with certain diseases can act as biomarkers for those conditions.

The US team that developed this method has successfully tried it on mice with a condition resembling multiple sclerosis. The researchers used the same approach on human patients with Alzheimer’s disease. They applied the screening technique to six Alzheimer’s patients, six Parkinson’s disease patients and six healthy control individuals. Three peptoids were identified that captured antibodies specific to Alzheimer’s. In these patients they were present in at least three-fold higher levels than in either the Parkinson’s or control groups. They also used the test on blood from 200 elderly people not suffering from dementia and found 8 percent had elevated concentrations of the same antibodies found in Alzheimer's patients, which suggests the test may work as an early predictor of disease.

According to Professor Thomas Kodadek, from Scripps Research Institute in La Jolla, California, “This study essentially puts an end to the notion that the only way to pull a potentially useful antibody from blood samples is with a specific antigen.” James Anderson of the National Institutes of Health which helped fund the study added, “Dr Kodadek has conceived of a new approach for identifying antibody biomarkers of human disease that bypasses the conventional, but difficult, step of identifying the natural antigens or antigen mimics…The results in the paper suggest great potential for using this approach to rapidly develop diagnostic biomarkers for a variety of significant human diseases.” Kodadek has licensed the technology to Miami-based OPKO Health Inc, which will develop diagnostic kits, which he thinks could be available in six to seven months.