S-Adenosylmethionine Is Decreased in the Cerebrospinal Fluid of Patients with Alzheimer’s Disease (original) (raw)

significantly lower CSF levels of the methyl group donor SAM (193 8 31 vs. 207 8 37 nmol/l; p = 0.032). Accordingly, the SAM/SAH ratio, which represents the methylation capacity, was significantly lower in the CSF of the AD patients (7.6 8 2.4 vs. 9.1 8 2.8; p = 0.003). Further, explorative analysis of all subjects showed that CSF SAM levels were lower in carriers of the APOE4 allele compared with noncarriers (189 8 30 vs. 207 8 36 nmol/l; p = 0.010). Of the individuals with CSF SAM levels in the lowest quartile, 63% carried the APOE4 allele compared with 17% of the individuals with CSF SAM levels in the highest quartile (Pearson: 2 = 9.9; p = 0.002; odds ratio 0.126, 95% confidence interval 0.32-0.49). Conclusion: These data suggest that AD is associated with lower CSF SAM levels and that this is at least partly due to an association of the APOE4 allele with reduced SAM levels in the CSF.