Now, 3 biomarkers in spinal fluid could classify patients with Alzheimer’s

August 10th, 2010 - 2:51 pm ICT by ANI  

Washington, Aug 10 (ANI): Three biomarkers could soon be able to classify people with Alzheimer’s disease from those without it.

A signature consisting of the three biomarkers in the cerebrospinal fluid was found in 90 percent of Alzheimer’s patients, and was also found in more than one-third of cognitively normal older adults, a report has revealed.

“The initiation of the Alzheimer’s disease pathogenic process is typically unobserved and has been thought to precede the first symptoms by 10 years or more,” authors of the report have written.

“Therefore, demonstrating that Alzheimer’s disease biomarkers, such as cerebrospinal fluid beta-amyloid protein (CSF), total CSF tau protein and CSF phosphorylated protein (P-Tau) concentrations are true indicators of the pathogenic process at an early stage is a major challenge,” they wrote.

Geert De Meyer of Ghent University, Ghent, Belgium, and colleagues in the Alzheimer’s Disease Neuroimaging Initiative analyzed data from 114 older adults who were cognitively normal, 200 who had mild cognitive impairment and 102 who had Alzheimer’s disease.

They first modelled the data from all participants, without considering their cognitive status, to identify profiles that had different levels of three biomarkers: CSF, total CSF tau protein and P-Tau.

One profile or signature was presumed to be associated with Alzheimer’s disease while the other matched a healthy status.

When these profiles were applied to the data in the subgroups, the Alzheimer’s disease signature was found in 90 percent of those with Alzheimer’s disease, 72 percent of those with mild cognitive impairment and 36 percent of those who were cognitively normal.

“Results were validated on two other data sets. In one study consisting of 68 autopsy-confirmed Alzheimer’s disease cases, 64 of 68 patients (94 percent sensitivity) were correctly classified with the Alzheimer’s disease feature. In another data set with 57 patients with mild cognitive impairment followed up for five years, the model showed a sensitivity of 100 percent in patients progressing to Alzheimer’s disease,” wrote the authors.

The results suggest that this signature of biomarkers developed independently of data on clinical diagnosis of Alzheimer’s disease can correctly classify patients with the condition.

“The unexpected presence of the Alzheimer’s disease signature in more than one-third of cognitively normal subjects suggests that Alzheimer’s disease pathology is active and detectable earlier than has heretofore been envisioned,” the authors wrote.

“Thus, taken together, these data provide further support for the view that revision of current diagnostic criteria for Alzheimer’s disease is needed, or at least as far as early-stage Alzheimer’s disease is concerned,” they concluded.

The report was published in the August issue of Archives of Neurology. (ANI)

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