Evaluation of dementia by acrolein, amyloid-β and creatinine

• PC-Acro and Aβ40/42 in plasma were higher in AD and MCI than in control.
• 3-HPMA/Cre and AC-Acro/Cre in urine were lower in AD patients than in MCI patients.
• Reduction in 3-HPMA/Cre in urine was correlated with an increase in Aβ40/42 in plasma.
• Aβ40/PC-Acro, Aβ40 and Aβ40/42 in CSF were lower in AD patients than in MCI patients.
• The changes of these biomarkers in plasma, urine and CSF were correlated with MMSE.

Plasma, urine and cerebrospinal fluid (CSF) were examined for biochemical markers of dementia. Protein-conjugated acrolein (PC-Acro) and the amyloid-β (Aβ)40/42 ratio in plasma can be used to detect mild cognitive impairment (MCI) and Alzheimer's disease (AD). In plasma, PC-Acro and the Aβ40/42 ratio in MCI and AD were significantly higher relative to non-demented subjects. Furthermore, urine acrolein metabolite, 3-hydroxypropyl mercapturic acid (3-HPMA)/creatinine (Cre) and amino acid-conjugated acrolein (AC-Acro)/Cre in AD were significantly lower than MCI. It was also shown that reduced urine 3-HPMA/Cre correlated with increased plasma Aβ40/42 ratio in dementia. The Aβ40/PC-Acro ratio in CSF, together with Aβ40 and Aβ40/42 ratio, was lower in AD than MCI. Increased plasma PC-Acro and Aβ40/42 ratio and decreased urine 3-HPMA/Cre correlated with cognitive ability (MMSE). These results indicate that the measurements of acrolein derivatives together with Aβ and Cre in biologic fluids is useful to estimate severity of dementia.