Serum 24-hydroxycholesterol in probable Alzheimer's dementia: Reexploring the significance of a tentative Alzheimer's disease biomarker.

OBJECTIVE:This study measured and analyzed the serum levels of 24-hydroxycholesterol in patients with probable Alzheimer's disease (AD) and age-/sex-matched controls. METHODS:A case-control study involving 40 AD patients and 40 controls was performed at a tertiary neurological teaching hospital in eastern India. Blood and serum samples were collected for APOERESULTS:Serum 24-hydroxycholesterol was significantly lower in AD patients compared to controls (median concentration: controls, 47.14 ng/mL (interquartile range, 16.34); AD patients, 32.93 ng/mL (interquartile range, 9.45); PrPrPAPOE4PCONCLUSION:The decreased 24-hydroxycholesterol level in peripheral circulation in AD cases observed in the present study may suggest its role in AD pathogenesis. The lack of a clear correlation between serum levels of 24-hydroxycholesterol and MMSE score-a surrogate marker of AD severity-raises the question as to whether 24-hydroxycholesterol level declines with decreasing neuronal mass or whether the steroid continues to play a protective role.