Serum Amyloid-Beta Levels are Increased in Patients with Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is associated with cognitive decline, but the molecular link between COPD and dementia or Alzheimer's disease (AD) remains unclear. This study was aimed to investigate whether serum Aβ levels are correlated with COPD. 77 cognitively normal COPD patients and 45 age- and gender-matched normal controls were admitted to the study. Serum Aβ40 and Aβ42 levels were measured using ELISA kits. Serum C-reactive protein (CRP), interleukin 6 (IL-6), and procalcitonin (PCT) measurements were done using standard laboratory methods. Pulmonary function tests were performed to assess the pulmonary function and determine the degree of lung damage. Significantly increased levels of serum Aβ40, Aβ42, and total Aβ levels were found in patients with COPD in comparison with normal controls. In COPD patients, serum Aβ levels were higher in subjects with serum CRP, IL-6, and PCT upper the limit of normal. Moreover, serum Aβ levels were dramatically higher in COPD patients with worse pulmonary function. Our study suggests that cognitively normal COPD patients may undergo AD-related pathological changes, and COPD might facilitate AD-type pathogenesis.