Researchers plan to analyze 21,000 plasma samples for mixed dementia
Researchers are tackling the biological complexity of mixed dementia by planning to analyze approximately 21,000 plasma samples collected over time from 10,000 participants in the US Alzheimer’s Disease Research Centers program. The proteomics initiative aims to identify patterns of blood proteins that help distinguish the multiple underlying pathologies contributing to cognitive impairment.
Key Clinical Takeaways:
- A new proteomics initiative will analyze roughly 21,000 longitudinal plasma samples from 10,000 participants to untangle mixed dementia.
- Researchers are using the NULISAseq Neuro 220 panel to detect multiple neurodegenerative pathologies simultaneously.
- The project aims to improve clinical trial design by enabling better participant prescreening based on underlying biological profiles.
Why Does Alzheimer’s Disease Diagnosis Often Fail to Explain Entire Clinical Presentations?
A clinical diagnosis of Alzheimer’s disease does not necessarily capture every pathological process occurring within a patient’s brain. While amyloid plaques accumulate between neurons and tau tangles form inside them, these classic hallmarks frequently coexist with vascular damage and other abnormal protein deposits. When multiple distinct disease processes drive cognitive decline simultaneously, clinicians classify the condition as mixed dementia. Patients presenting with identical cognitive symptoms may harbor entirely different combinations of underlying pathologies, which directly influences their individual prognoses and responses to targeted therapeutics.
“Typically, more than just Alzheimer’s disease is contributing to their dementia,” said Sterling Johnson, a dementia researcher at the University of Wisconsin–Madison. Johnson, alongside Sarah Biber, an Associate Professor of Neurology at Washington University in St. Louis, and Tatiana Foroud, Professor in the Department of Medical and Molecular Genetics at Indiana University, is addressing this diagnostic challenge through a collaborative proteomics initiative. The project operates under the Consortium for Clarity in ADRD Research Through Imaging, known as CLARiTI.
How Do Researchers Plan to Analyze 21,000 Plasma Samples Using the NULISAseq Panel?
The research team is using a specialized proteomics tool to road-test thousands of biological samples against a broad spectrum of neurodegenerative markers. The initiative utilizes the NULISAseq Neuro 220 panel, an assay system designed to measure proteins relevant not only to Alzheimer’s disease but also to a wider array of neurodegenerative pathologies. By examining plasma samples collected over extended periods from the National Institute on Aging’s Alzheimer’s Disease Research Centers program, the investigators intend to disentangle the biological heterogeneity inherent in cognitive disorders.
“We are very interested in detecting the multiple pathologies that ultimately contribute to cognitive impairment in someone presumed to have Alzheimer’s disease,” Johnson stated. The selected cohort provides longitudinal blood samples paired with detailed clinical assessments, standardized neuroimaging, and, in approximately 60 percent of participants, committed brain donation. This extensive multimodal data linkage supplies the neuropathological ground truth required to validate blood-based biomarker signatures against actual post-mortem tissue changes.
What Role Will the eMTBR-tau243 Marker Play in Biological Staging and Clinical Trials?
In addition to standard panels, the initiative measures specific emerging biomarkers, including eMTBR-tau243, to evaluate disease progression more precisely than conventional assays allow. While plasma p-tau217 remains exceptionally effective for identifying core Alzheimer’s disease biology and amyloid pathology, eMTBR-tau243 correlates more directly with the actual burden of fibrillar tau tangles. This distinction helps investigators determine where a patient stands biologically along the timeline of neurodegeneration.
According to Johnson, individuals exhibiting elevated p-tau217 alongside normal or low eMTBR-tau243 may represent an ideal therapeutic window for amyloid-lowering interventions, since Alzheimer’s biology is present without extensive fibrillar tau development. Biber noted that these insights could transform clinical trial design. Sponsors often struggle with mixed cohorts; assays developed from this project could enable trial organizers to prescreen participants accurately and match them to therapies tailored to their specific etiological profile.
Can Open Data Challenges Accelerate Multimodal AI Model Development for Dementia Prediction?
The project plans to release linked multimodal data to global research teams to address concrete predictive questions, such as estimating the timeline of transition from normal cognition to mild cognitive impairment or calculating the relative contributions of competing pathologies in an individual patient.
Despite the rapid advancement of blood-based assays, debates persist within the biomarker community regarding whether plasma proteins will eventually suffice or if positron emission tomography and other imaging modalities remain mandatory.