Because cerebrospinal fluid (CSF) abnormalities in presymptomatic subjects with PSEN1 (presenilin 1) mutations may be observed 4 to 12 years prior to the estimated age at onset, it is possible to test putative therapies on the CSF analytes that correlate with neurodegeneration during this presymptomatic window of clinical opportunity. It is also possible to test the same therapy on a comparison group with increased risk status conferred by both hyperlipidemia and heterozygosity for apolipoprotein Eε4. To our knowledge, the only putative therapy thus far tested in such a common design has been statin therapy. The results of these tests show increases in soluble amyloid precursor protein (sAPP)α correlating with statin-induced decreases in serum cholesterol levels in the non-PSEN1 subjects. This result could be one functional correlate for part of the substantial risk reduction for late onset Alzheimer's disease recently reported in the Rotterdam study, a large, long-term prospective statin trial. Statin therapy significantly decreased both sAPPα and sAPPβ in presymptomatic PSEN1 subjects. Initially, elevated phospho-tau levels in PSEN1 subjects did not further increase during the 2 to 3 years of statin therapy, possibly indicative of a prophylactic effect. These results suggest that large and longer term trials of statin therapy correlating changes in CSF biomarker levels with clinical course may be warranted in both presymptomatic PSEN1 and non-PSEN1 subjects.

BACKGROUND/AIMS: It is not yet established whether statins (lipophilic or hydrophilic) reduce the risk of Alzheimer's disease and, if so, by differentially modifying brain lipid levels. Our aim was to assess changes in brain cholesterol metabolism as reflected in the cerebrospinal fluid (CSF) before and after treatment with either atorvastatin or simvastatin. METHODS: We carried out a longitudinal analysis of CSF cholesterol, lathosterol and 24(S)-hydroxycholesterol before and after treatment with maximum doses of statins in 10 asymptomatic subjects, 8 of whom were heterozygous for apolipoprotein E epsilon4, and in 6 presymptomatic PS1 subjects. RESULTS: Statins initially reduced CSF lathosterol cholesterol and 24(S)-hydroxycholesterol in both PS1 and non-PS1 subjects reaching a nadir at 6-7 months, followed by a return to baseline at 15 months with an overshoot at 2 years, tending to return to baseline thereafter. CONCLUSIONS: Possible long-term protective effects of statins are not likely largely related to the temporally-dependent biphasic effects of statin therapy upon the magnitude and direction of changes in CSF lipid levels and their subsequent return to baseline levels.