Immuno-Infrared Sensor is Able to Identify Symptom-Free Alzheimer Disease
Alzheimer disease (AD) is thought to begin 15 to 20 years before clinical symptoms are seen, making early identification of presymptomatic disease a priority. As published in the journal Alzheimer’s & Dementia, new results compared sensitivity of an immune-infrared sensor with the complementary single-molecule array (SIMOA) technology results, which were published in the same journal in March 2022.
With this newly developed immuno-infrared sensor, researchers have been able to track misfolded amyloid-beta (Aβ) in the blood up to 17 years before the first clinical symptoms of AD appear.
“Our goal is to determine the risk of developing AD at a later stage with a simple blood test even before the toxic plaques can form in the brain, in order to ensure that a therapy can be initiated in time,” says professor Klaus Gerwert, founding director of the Centre for Protein Diagnostics (PRODI) at Ruhr-Universität Bochum. His team cooperated for the study with a group at the German Cancer Research Centre in Heidelberg (DKFZ) headed by professor Hermann Brenner.
Development of Alzheimer disease in 68 study participants was accurately predicted by the findings of the immune-infrared assay. SIMOA technology evaluated phospho-tau 181 levels in study participants, but did not accurately predict development of AD.
“Unlike in the clinical phase, however, this marker is not suitable for the early symptom-free phase of AD,” as Klaus Gerwert summarizes the results of the comparative study. “Surprisingly, we found that the concentration of glial fiber protein (GFAP) can indicate the disease up to 17 years before the clinical phase, even though SIMOA does so much less precisely than the immuno-infrared sensor.”
Combining misfolded Aβ and GFAP concentration increased accuracy of the test in the symptom-free stage. Combined receiver-operating characteristic (ROC) curve analyses showed an area under the curve of 0.83 for the combination of misfolded Aβ misfolding, apolipoprotein E gene status, and GFAP. APOE status did not increase the discriminative power of misfolded Aβ and GFAP, suggesting that only these two blood-based biomarkers are favored.
The combined receiver operating characteristics (ROC) showed the highest area under the ROC curve for the biomarkers Aβ misfolding for APOE status and GFAP was 0.83. Only the combination of amyloid-beta misfolding and GFAP concentration were favored.
“We plan to use the misfolding test to establish a screening method for older people and determine their risk of developing AD,” says Klaus Gerwert. “The vision of our newly founded start-up betaSENSE is that the disease can be stopped in a symptom-free stage before irreversible damage occurs.” Even though the sensor is still in the development phase, the invention has already been patented worldwide. BetaSENSE aims to bring the immuno-infrared sensor to market and have it approved as a diagnostic device so that it can be used in clinical labs.