Distinction between mild cognitive impairment and Alzheimer's disease by CSF amyloid β40 and β42, and protein-conjugated acrolein

Abstract Background We found previously that the amyloid β 40/42 (Aβ 40/42 ) ratio and the level of protein-conjugated acrolein (PC-Acro) in plasma were increased in mild cognitive impairment (MCI) and Alzheimer's disease (AD) subjects. We determined whether MCI and AD subjects can be differentiated based on the levels of Aβ 40 , Aβ 42 , and PC-Acro in cerebrospinal fluid (CSF). Methods Aβ 40 , Aβ 42 , PC-Acro, Tau and phosphorylated Tau in CSF were measured by ELISA. Results Median values of Aβ 40 , Aβ 40 /PC-Acro and Aβ 40/42 in CSF were significantly lower in 54 AD subjects than those in 40 MCI subjects. Severity of VOI (volume of interest) atrophy was most intensely correlated with the decrease in Aβ 40 /PC-Acro and then that in Aβ 40 and Aβ 42 /PC-Acro. MMSE was most intensely correlated with the decrease in Aβ 42 and Aβ 40 , and then that in Aβ 42 /PC-Acro and Aβ 40 /PC-Acro. Conclusion A decrease in Aβ 40 /PC-Acro in CSF is well correlated with brain damage, and a decrease in Aβ 42 and Aβ 40 is well correlated with cognitive ability. Measurement of PC-Acro together with Aβ 40 and Aβ 42 provides a more precise evaluation of severity of AD subjects.