van Steenoven I, et al. - Researchers conducted this work to examine levels of various cerebrospinal fluid (CSF) Aβ peptides (Aβ38, Aβ40, Aβ42) in dementia with Lewy bodies [DLB; second most common neurodegenerative disease in the elderly after Alzheimer disease (AD)], AD, and cognitively normal controls to understand the putative role of altered amyloid-β (Aβ) metabolism in dementia with DLB. Using the Meso Scale Discovery assay for human Aβ peptides, CSF from patients with DLB (n = 72; age 68 ± 6 years; 10%F; Mini-mental State examination (MMSE) 23 ± 4), AD (n = 38; age 68 ± 6 years; 8%F; MMSE 22 ± 5), and cognitively normal controls (n = 38; age 67 ± 7 years; 13%F; MMSE 29 ± 2) was investigated. For all three CSF Aβ peptides and compared with controls (Aβ38 2676 ± 703 pg/ml, Aβ40 6243 ± 1500 pg/ml, and Aβ42 692 ± 205 pg/ml), lower levels were found in DLB (Aβ38 2247 ± 638, Aβ40 5432 ± 1340, and Aβ42 441 ± 185), while AD patients had lower levels of Aβ42 (304 ± 71). According to findings, different CSF Aβ reduction profiles have been shown in DLB and AD. Although AD is characterized in particular by an isolated decrease in Aβ42, DLB is correlated with reductions in Aβ38, Aβ40, and Aβ42. Even in the absence of co-morbid AD pathology, amyloid metabolism is affected in DLB.