Elevated Platelet β-Secretase Activity in Mild Cognitive Impairment

Background/Aims: We have recently reported that platelet activity of the rate-limiting enzyme for β-amyloid peptide production is elevated in established Alzheimer’s disease. Laboratory investigation of the very early stages of dementia provides an opportunity to investigate pathological mechanisms before advanced disease hinders interpretation. Mild cognitive impairment (MCI) exists prior to obvious dementia, and is associated with increased risk of conversion to overt disease. Methods: We developed and used a fluorimetric assay to quantify platelet membrane β-secretase activity in 52 patients with MCI and 75 controls. Results: Platelet membrane β-secretase activity was 24% higher in individuals with MCI compared to controls (p = 0.001, unpaired t test with Welch correction). Conclusion: Elevated platelet β-secretase activity in subjects with MCI is an area for further study in relation to the etiology and diagnosis of MCI.