First authored by post-graduate student Julie Zhu, we report here that Serum IL-8 may have clinical utility as a biomarker for white matter hyperintensities (WMH) in AD. This is the latest work in our ongoing efforts to examine serum inflammatory markers in preclinical stages of dementia and in AD, as well as to investigate their associations with concomitant cerebrovascular disease (CeVD), given that CeVD have been implicated in cognitive impairment and may worsen AD severity (Zekry et al., 2002). We performed a cross-sectional case-control study including 96 AD, 140 cognitively impaired no dementia (CIND), and 79 noncognitively impaired participants. All subjects underwent neuropsychological and neuroimaging assessments, as well as collection of blood samples for measurements of serum samples interleukin (IL)-6, IL-8, and tumor necrosis factor α levels. Subjects were classified as CIND or dementia based on clinical criteria. Significant CeVD, including white-matter hyperintensities (WMHs), lacunes, and cortical infarcts, was assessed by magnetic resonance imaging. After controlling for covariates, higher concentrations of IL-8, but not the other measured cytokines, were associated with both CIND and AD only in the presence of significant CeVD (CIND with CeVD: odds ratios [ORs] 4.53; 95% confidence interval [CI] 1.5-13.4 and AD with CeVD: OR 7.26; 95% CI 1.2-43.3). Subsequent multivariate analyses showed that among the types of CeVD assessed, only WMH was associated with higher IL-8 levels in CIND and AD (WMH: OR 2.81; 95% CI 1.4-5.6). Longitudinal follow-up studies would help validate these findings.

References

Zhu Y, Chai YL, Hilal S, et al. (This paper).

Zekry D, Duyckaerts C, Moulias R, et al. Degenerative and vascular lesions of the brain have synergistic effects in dementia of the elderly. Acta Neuropathol 103:481-7.