In the past several months, researchers have been focusing on easier point-of-care tests that offer early detection of diseases. One such test was recently proposed for Alzheimer’s disease, based on the idea of a portable biosensor
that will diagnose disease progression by measuring beta-amyloid protein levels in the blood. However, such test has already been developed in Germany, and researchers recently reported
84 percent diagnostic precision from their first clinical trial.
The newly patented diagnostic test was developed by a research team at the Ruhr-University Bochum in Germany. Instead of just measuring levels of the beta-amyloid proteins, a signature of Alzheimer’s, the new test uses an infrared sensor that detects pathological misfolding of the protein. The presence of such misfolded proteins can occur more than 15 years before symptoms appear in the patients, and thus offer unprecedented early detection for the disease.
To assay beta-amyloid misfolding, the new test uses specific antibodies to attract protein biomarkers from cerebrospinal fluid samples or blood samples. The patent-pending infrared technology then scans the proteins for the presence and total distribution of secondary structures. Unlike other enzyme-linked immunosorbent assays (ELISA) that give the concentrations of abnormally folded proteins, the new test gives information on the distribution of the secondary structures, which could offer higher precision.
"We do not merely select one single possible folding arrangement of the peptide; rather, we detect how all existing Amyloid beta secondary structures are distributed, in their healthy and in their pathological forms," said Klaus Gerwert, senior study author.
In a small clinical trial of 141 patients, the new test achieved a diagnostic precision of 84 percent in the blood and 90 per cent in cerebrospinal fluid. "What's unique about it is that this is the only robust label-free test with a single threshold," said Andreas Nabers, first study author.
Alzheimer’s disease is highly prevalent, accounting for over 7 million new cases every year. While there’s no cure yet, the detection and early diagnosis of the disease could influence patient care and outcome. According to the study authors, current diagnosis for the disease comes too late, as severe irreversible brain damages have already occurred in the time it takes for clinical symptoms to manifest. "If we wish to have a drug at our disposal that can significantly inhibit the progress of the disease, we need blood tests that detect Alzheimer's in its pre-dementia stages," said Gerwert. In catching Alzheimer early, researchers could have the rare opportunity to administer drugs to possibly prevent, or at the very least, delay its progression.
Additional source: Ruhr-Universität Bochum press release