EMBARGOED FOR RELEASE UNTIL 4 PM ET, June 22, 2011
New Biomarker May Help with Early Diagnosis of Alzheimer鈥檚 Disease
ST. PAUL, Minn. -
A new biomarker may help identify which people with mild memory deficits will go on to develop , according to a new study published in the June 22, 2011, online issue of the medical journal of the . The biomarker may be more accurate than the currently established biomarkers. 鈥淏eing able to identify who will develop Alzheimer鈥檚 disease very early in the process will be crucial in the future,鈥 said study author Robert Perneczky, MD, of the Technical University Munich in Germany. 鈥淥nce we have treatments that could prevent Alzheimer鈥檚 disease, we could begin to treat very early and hopefully prevent the loss of memory and thinking skills that occurs with this devastating disease.鈥 The study involved 58 people with slight memory problems, or mild cognitive impairment (MCI). Up to 15 percent of people with mild cognitive impairment develop Alzheimer鈥檚 disease each year. A sample of cerebrospinal fluid of the participants was taken at the beginning of the study through a lumbar puncture, or spinal tap. The concentrations in the cerebrospinal fluid of several proteins that are associated with Alzheimer鈥檚 disease were measured. The participants were followed for nearly three years on average. At that point, 21 people had developed Alzheimer鈥檚 disease, 27 still had mild cognitive impairment and eight people had reverted back to their normal cognitive health. Two people had developed frontotemporal dementia, and their results were not included in the analysis. Researchers found that the people who developed Alzheimer鈥檚 disease had significantly higher levels of a protein called soluble amyloid precursor protein beta (sAPP?) in their spinal fluid than those who did not develop Alzheimer鈥檚 disease. Those who developed Alzheimer鈥檚 disease had an average of 1,200 nanograms per milliliter, compared to 932 for those who did not develop the disease. The researchers found that the best predictor of whether someone would develop Alzheimer鈥檚 disease was a combination of sAPP?, the tau protein (an established marker of brain cell damage) and the age of the individual. When these factors were combined, the results were roughly 80 percent accurate in predicting whether the disease would develop. The protein amyloid beta1-42, or A?1-42, which has previously been considered a biomarker for Alzheimer鈥檚 disease, was not a predictive factor in this study. 鈥淭hese results suggest that sAPP? as a biomarker may be useful and superior to the established marker A?1-42 in the early diagnosis of Alzheimer鈥檚 disease,鈥 Perneczky said. 鈥淥ne possible explanation is that A?1-42 measures events further downstream from the initial steps that lead to the production of the amyloid plaques that accumulate in the brains of people with Alzheimer鈥檚 disease. sAPP? is a measure of the first critical step in that process and may therefore provide more accurate information on the core pathological events.鈥 The study was supported by the League of Friends of the Technical University Munich and the Commission for Clinical Research of the Rechts der Isar Munich Hospital.