Levels of amyloid-beta-42 and CSF pressure are directly related in patients with Alzheimer's disease.

Experimental data suggest that the cerebrospinal fluid (CSF) dynamic is involved in the clearance of beta-amyloid, a key event in the pathogenesis of Alzheimer's disease (AD). At this regard no evidence still exists in vivo. In this study we explored the relationships between CSF pressure and AD pathology, as measured with CSF core biomarkers. We enrolled 16 patients with probable AD and 21 controls, collecting demographics, clinical data, CSF opening pressure and CSF levels of beta-amyloid-42 fragment (Aβ42), total-tau (t-tau), phosphorylated-tau-181 (p-tau), albumin and albumin ratio. Differences between the groups were calculated with non-parametric tests, while correlations among all parameters were separately calculated with Spearman's test in each group. The groups significantly differed in biomarkers' concentration with lower Aβ42, and higher t-tau and p-tau in AD patients. Moreover, CSF pressure was significantly lower in AD group (11.0 ± 2.8 vs. 13.3 ± 3.0 mmHg, p < 0.05) and directly correlated with Aβ42 levels (R = 0.512; p < 0.05), but not with other biomarkers or parameters. No significant correlations emerged for biomarkers in control group. AD patients exhibit low CSF pressure whose values are directly and selectively related to CSF Aβ42 levels. This interesting correlation may confirm in vivo the association between CSF dynamic and beta-amyloid metabolism occurring in AD.