Circulating biomarkers of cognitive decline and dementia.
Plasma and serum biochemical markers proposed for cognitive decline of degenerative (Alzheimer's disease, AD) or vascular origin and predementia syndromes (mild cognitive impairment and other related entities) are based on pathophysiologic processes such as lipoprotein metabolism (total cholesterol, apolipoprotein E, 24S-hydroxy-cholesterol), and vascular disease (homocysteine, lipoprotein(a)); SP formation (amyloid beta(Abeta)-protein, Abeta autoantibodies, platelet APP isoforms), oxidative stress (isoprostanes, vitamin E), and inflammation (cytokines). This review will focus on the current knowledge on circulating serum and plasma biomarkers of cognitive decline and dementia that are linked to cholesterol homeostasis and lipoprotein abnormalities, senile plaque formation and amyloid precursor protein (APP) metabolism, oxidative stress, and inflammatory reactions. Special emphasis will, however, be placed on biomarkers related to lipoprotein metabolism and vascular disease. Analytically, most plasma and serum proteins or metabolites lack reproducibility, sensitivity, or specificity for the diagnosis, risk and progression assessment, or therapeutic monitoring of AD and other dementing disorders. Measures linked to lipoprotein metabolism and vascular disease, APP metabolism, oxidative stress, or inflammation appear altered in AD relative to controls, but lack sufficient discriminatory power. Measures combining several biomarkers or incorporating a range of proteins in plasma and small molecule metabolites are promising approaches for the development of plasma or serum-based diagnostic tests for AD and other dementing disorders, as well as for predementia syndromes.
Solfrizzi
Vincenzo
V
Department of Geriatrics, Center for Aging Brain, Memory Unit, University of Bari, Policlinico, Piazza Giulio Cesare, 11-70124 Bari, Italy.
D'Introno
Alessia
A
Colacicco
Anna Maria
AM
Capurso
Cristiano
C
Todarello
Orlando
O
Pellicani
Vincenza
V
Capurso
Sabrina A
SA
Pietrarossa
Giuseppe
G
Santamato
Vito
V
Capurso
Antonio
A
Panza
Francesco
F
D016229:Amyloid beta-Peptides / Q000097:blood; D015415:Biomarkers / Q000097:blood*; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D003072:Cognition Disorders / Q000097:blood / Q000175:diagnosis*; D003704:Dementia / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D006888:Hydroxycholesterols / Q000097:blood; D010446:Peptide Fragments / Q000097:blood
D016229:Amyloid beta-Peptides; D015415:Biomarkers; D008076:Cholesterol, HDL; D006888:Hydroxycholesterols; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); C044563:24-hydroxycholesterol; D002784:Cholesterol