Increased myeloperoxidase plasma levels in patients with Alzheimer's disease

Background: Increasing evidence supports the role of cardiovascular risk factors in the development of Alzheimer's disease (AD).

Objective: In the present pilot study, we investigated plasma concentrations of myeloperoxidase (MPO) and its possible association with plasma amyloid-β (Aβ)1-42/1-40 ratio in AD patients and elderly healthy controls.

Methods: The study sample included 28 AD patients and 27 elderly individuals with a normal cognitive status as a control group. The Mini-Mental Status Examination was used to determine the global cognition. MPO, Aβ1-40, and Aβ1-42 plasma concentrations were measured by enzyme linked immunoabsorbent assays.

Results: AD patients showed significantly higher plasma concentrations of MPO in comparison to healthy elderly controls (AD versus healthy elderly controls (mean ± SD): 132.8 ± 114.8 ng/mL versus 55.0 ± 42.6 ng/mL; p = 0.002). MPO plasma concentrations showed a significant positive correlation in the whole sample with the presence of AD (ρ = 0.428, p < 0.001) and its stage (ρ = 0.331; p = 0.013) as well as with plasma concentrations of Aβ1-42 (ρ = 0.406; p = 0.004) and Aβ1-42/1-40 ratio (ρ = 0.354; p = 0.013). In a binary logistic regression model, plasma MPO concentrations were independently associated with the presence of AD (p = 0.014).

Conclusion: AD patients showed significantly increased plasma levels of MPO, which could be an important molecular link between atherosclerosis and AD. Further studies should evaluate whether MPO may also be a useful biomarker and potential new treatment target in AD.