Application of QPLEXTM biomarkers in cognitively normal individuals across a broad age range and diverse regions with cerebral amyloid deposition

Abstract

The deposition of beta-amyloid (Aβ) in the brain precedes the onset of symptoms such as cognitive impairment in Alzheimer’s disease (AD); therefore, the early detection of Aβ accumulation is crucial. We previously reported the applicability of the QPLEXTM Alz plus assay kit for the prescreening of Aβ accumulation. Here, we tested the specific application of the kit in a large cohort of cognitively normal (CN) individuals of varying ages for the early detection of Aβ accumulation. We included a total of 221 CN participants with or without brain Aβ. The QPLEXTM biomarkers were characterized based on age groups (1st–3rd tertile) and across various brain regions with cerebral amyloid deposition. The 3rd tertile group (>65 years) was found to be the most suitable age group for the application of our assay kit. Receiver operating characteristic curve analysis showed that the area under the curve (AUC, discrimination power) was 0.878 with 69.7% sensitivity and 98.4% specificity in the 3rd tertile group. Additionally, specific correlations between biomarkers and cerebral amyloid deposition in four different brain regions revealed an overall correlation with general amyloid deposition, consistent with previous findings. Furthermore, the combinational panel with plasma Aβ1–42 levels maximized the discrimination efficiency and achieved an AUC of 0.921 with 95.7% sensitivity and 67.3% specificity. Thus, we suggest that the QPLEXTM Alz plus assay is useful for prescreening brain Aβ levels in CN individuals, especially those aged >65 years, to prevent disease progression via the early detection of disease initiation.

Sex differences in the progression of glucose metabolism dysfunction in Alzheimer’s disease

“…Participant recruitment was based on the protocol from the Korea Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer’s disease (KBASE), and the inclusion and exclusion criteria for the participants have been described in our previous paper 19 . Participants were further divided into PiB-PET-negative ( n = 127) and PiB-PET-positive groups ( n = 54) at the baseline timepoint, according to the standardized uptake value ratio (SUVR) value of 1.4 (PiB-PET negative participants had SUVR < 1.4 in all four different regions of interest; PiB-PET positive participants had SUVR > 1.4 in at least one of the four regions of interest; these regions of interest included the frontal, lateral temporal, lateral parietal, and posterior cingulate-precuneus regions) 17 , 19 , 20 . Moreover, participants also underwent 18 F fluorodeoxyglucose-PET (FDG-PET) and magnetic resonance imaging (MRI) using a 3.0-T Biograph mMR (PET-MR) scanner (Siemens, Washington, DC, USA).…”

Proteomic evidence for amyloidogenic cross-seeding in fibrinaloid microclots

“…It features in these fibrinaloid microclots despite being one of the least abundant plasma proteins of those under consideration (372 ng/mL according to [371], 98 ng/mL in [412] and just 10 ng/mL according to [413,414]) (209 ng/mL is stated for serum [415]). Interestingly, however, as well as being among the most amyloidogenic of those surveyed (Figure 10), it is highly predictive of Aβ deposition [382,416] and is also involved in lung fibrosis [417,418]. Finally, the fourth is LPLC1 (also known as BPIB1 or BPIFB1).…”

The QPLEX™ Plus Assay Kit for the Early Clinical Diagnosis of Alzheimer’s Disease

“…When the algorithm value exceeds the cutoff value, we assume that the participants may be at risk for AD. The current study shows that a QPLEX™ Alz plus assay kit could be used for cerebral amyloid deposition diagnosis [ 21 , 34 , 35 ]. However, all studies were developed and applied with the Korean Brain Aging Study for the Early diagnosis and prediction of Alzheimer’s disease (KBASE) cohort.…”