Neurology and Neurosurgery

Feb. 24, 2024

More than half of patients who have dementia with Lewy bodies (DLB) have concurrent Alzheimer's disease pathology that can affect the development and severity of DLB. Although Alzheimer's disease biomarkers can be detected in plasma, they haven't been widely studied in patients with DLB.

Mayo Clinic researchers have found that blood tests can accurately detect the presence of Alzheimer's disease pathology in patients who have DLB — even in the prodromal stages of disease.

As described in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, the researchers analyzed plasma from individuals across the DLB continuum. After quantifying a panel of Alzheimer's disease plasma biomarkers in groups within that continuum, the researchers compared those values with the values of biomarkers in clinically healthy individuals. Study participants also had PET scans.

Key findings:

• Abnormal levels of glial fibrillary acid protein (GFAP) — a marker of astrocytic activation — can be detected in plasma as early as the prodromal stage of mild cognitive impairment with Lewy bodies (MCI-LB).
• Plasma pTau-181 and neurofilament light reach abnormal levels later on the DLB continuum. Plasma pTau-181 levels were comparable to controls in individuals with isolated REM sleep behavior disorder and MCI-LB.
• Higher plasma GFAP was associated with higher amyloid beta burden across the entire DLB continuum and accurately identified brain amyloid pathology in DLB.
• Plasma pTau-181 showed the highest accuracy in detecting abnormal amyloid and tau PET in patients with DLB.

The researchers note that plasma biomarkers are good candidates to determine the presence of Alzheimer's disease pathologic changes in the DLB continuum. Plasma GFAP can potentially be used to determine amyloid-related pathology in prodromal stages of DLB, while pTau-181 appears to be the optimal plasma biomarker to detect both amyloid beta and tau pathologies across the DLB continuum.

The findings also have relevance for future efforts to determine the clinical benefits of modifying Alzheimer's pathology in patients with DLB. "Having blood-based biomarkers that can screen for Alzheimer's pathology makes it easier and cheaper to screen large numbers of DLB patients for clinical trials," says Kejal Kantarci, M.D., a radiologist at Mayo Clinic in Rochester, Minnesota. "The blood test is noninvasive, accessible and inexpensive."

For more information

Diaz-Galvan P, et al. Plasma biomarkers of Alzheimer's disease in the continuum of dementia with Lewy bodies. Alzheimer's & Dementia: The Journal of the Alzheimer's Association. In press.

Refer a patient to Mayo Clinic.