No relationship between lipoprotein-associated phospholipase A2, proinflammatory cytokines, and neopterin in Alzheimer's disease

Objective: Lipoprotein-associated phospholipase A2 (Lp-PLA(2)) is a reported risk factor for dementia. However, the relationship between Alzheimer's disease (AD) and Lp-PLA(2) is still debatable and, to the best of our knowledge, no study has evaluated the associations between levels of Lp-PLA(2), proinflammatory cytokines, and neopterin in AD. Methods: In total, 59 patients with AD and 38 non-demented individuals were included in the case-control study. Fasting serum concentrations of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), neopterin, and Lp-PLA(2) were determined using ELISA. The associations between AD and each of the variables were analyzed by logistic regression. Results: The median Lp-PLA(2) levels in AD and controls were similar (P = 0.29, not significant). Median serum neopterin and IL-6 levels were significantly higher in patients with AD than in controls (P = 0.0001 and P = 0.03, respectively). In regression analyses, median neopterin levels, a lower level of education, and female gender were significantly associated with AD when compared with controls (OR, 31.44, 95% CI 3.59-275.28, P=0.002; OR, 4.35, 95% CI 1.13-16.61, P = 0.032; OR, 7.25, 95% CI 1.88-28.00, P = 0.004, respectively). Conclusion: In contrast to previous evidence suggesting its role in dementia and AD, Lp-PLA(2) enzyme levels were higher in the controls, and no relationship between Lp-PLA(2) and either proinflammatory cytokines or neopterin was identified in AD. Elevated neopterin levels may be considered inflammatory markers of AD. (C) 2016 Elsevier Inc. All rights reserved.