CSF markers in Alzheimer disease patients are not related to the different degree of cognitive impairment.
Standard markers in cerebrospinal fluid (CSF), as soluble amyloid beta 1-42 (Abeta1-42) and total tau protein (t-tau), may contribute to dementia subtypes diagnostic accuracy. Yet, their sensitivity to assess the different degree of cognitive deficit is not fully clarified. Our study analyses Abeta1-42 and t-tau CSF levels in different cohorts of Alzheimer's disease (AD) patients, distinguished as early AD (mild cognitively impaired subjects recently converted to AD), mild AD (MMSE<23; > or =18), and moderately advanced AD (MMSE<18). The control group was represented by age-matched patients affected by depressive pseudo-dementia. Reduced Abeta1-42 and increased t-tau CSF levels were confirmed as hallmarks of AD at any disease stage. In early AD patients, Abeta1-42 levels were already significantly low, if compared to the control group (336 vs 867 ng/L; p<0.0001). On the contrary, Abeta1-42 levels did not differ between AD subgroups, and in particular between mild to moderate AD. A significant progressive increase of t-tau concentration was found when comparing early AD (269 ng/L) to more advanced AD stages (468 ng/L and 495 ng/L for mild and moderate AD, respectively). Our findings confirm that the impairment of amyloidogenic cascade is an early, even pre-clinical process, but suggest that soluble Abeta1-42 concentration has a negligible correlation with the clinical progression. Conversely, t-tau concentration correlates with the transition towards marked cognitive impairment.
Stefani
Alessandro
A
IRCCS-Fondazione S Lucia, Rome, Italy. stefani@uniroma2.it
Martorana
Alessandro
A
Bernardini
Sergio
S
Panella
Marta
M
Mercati
Flavio
F
Orlacchio
Antonio
A
Pierantozzi
Mariangela
M
D000368:Aged; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid* / Q000150:complications; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid*; D015415:Biomarkers / Q000134:cerebrospinal fluid; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000134:cerebrospinal fluid* / Q000209:etiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010446:Peptide Fragments / Q000134:cerebrospinal fluid*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016875:tau Proteins / Q000134:cerebrospinal fluid*
D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016875:tau Proteins