P2‐037: Alzheimer'S disease (ad) and mild cognitive impairment (mci) patients are characterized by increased bdnf serum levels

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline with loss of memory. In the last years there has been a great interest on the early phases of AD, trying to identify the pathogenic mechanisms of AD and define early treatment modalities. In particular, Mild Cognitive Impairment (MCI) is attractive because it represents a transitional state between normal aging and dementia, although not all MCI patients automatically convert to AD. The neurotrophin brain-derived neurotrophic factor (BDNF) is critical for survival and function of neurons that degenerate in AD and represents a potential neuroprotective agent. However, opposite data on serum levels of BDNF have been reported in AD patients, probably reflecting differences in patient recruitment and stage of the disease. Thus, in order to further elucidate the role of BDNF in MCI and AD in this study we measured BDNF serum levels in three distinct groups of subjects: 1) AD patients; 2) MCI patients; 3) Healthy subjects. Moreover, since BDNF could be actively modified by AchEI or antidepressiant drugs, we investigated whether BDNF serum levels might be differently altered in the subgroup of AD patients free of these pharmacological treatments. Eighty-nine AD patients, 54 MCI patients and 27 Healthy subjects were enrolled in the study. Venous blood was drawn from all fasted subjects at their first clinical evaluation. After clotting, sampling tubes were centrifuged at 2000×g for 20 minutes. Serum was then aliquoted and stored at -80 °C until analysis. BDNF was detected in sandwich ELISAs according to the manufacturer's instructions (R and D Systems, Minneapolis, MN, USA). We found that serum BNDF levels were significantly increased in MCI and AD patients when compared to Healthy subjects and this increase in AD patients was not dependent on treatment with Acetylcholinesterase inhibitors or antidepressant medications. Our findings indicate that BDNF serum levels increase in MCI and AD patients, supporting the hypothesis of an upregulation of BDNF in both preclinical (MCI) and clinical stages of AD. Other studies are necessary to establish a direct link between BDNF peripheral levels and AD course in determining these events.