P3-049: Serum brain-derived neurotrophic factor in people with untreated Alzheimer's disease: Correlation with mood and cognition

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline with loss of memory. Brain-derived neurotrophic factor (BDNF) is critical for survival and function of neurons that degenerate in AD and it has become a key target in the physiopathology of several psychiatric diseases; and several drugs modified BDNF serum levels. So, opposite data on serum levels of BDNF have been reported in AD patients, probably reflecting differences in patient recruitment, stage of the disease and concomitant drugs. Thus, in this study we measured BDNF serum levels in new onset diagnosed AD patients (low and moderate severity) without treatment with acetylcholinesterase inhibitors and antidepressive drugs. BDNF serum concentrations were assessed by a sensitive ELISA in 63 AD patients in comparison to 48 age-matched healthy. Participants taking acetylcholinesterase inhibitors and antidepressive drugs were excluded. Participants underwent an extensive neuropsychological battery according to standards of our unit. We found a significant decrease of BDNF serum concentration in AD (199.91 pg/ml) compared to healthy controls (300.2 pg/ml; p = 0.01) and in patients with depression according to Cornell Scale (261.9 vs 128.3 pg/ml; p=0.04). BDNF serum concentrations were lower in AD with depression follow to AD without depression, controls with depression and finally controls without depression (151.8 pg/ml, 183.9, 187.7, 239.8; p=0.06). Apahty was most important neuropsychiatric symptom and was correlated with lower levels of BDNF (259.2 vs 172.6 pg/ml; p=0.05). Also BDNF was correlated with MMSE (p=0.004), semantic verbal fluency (p=0.001) and drawing clock test (p=0.003). No correlated with other neuropsicological tests. Comparing mild and moderated AD, patients with MMSE lower than 18 have lower levels of BDNF (133.5 vs 274.7 pg/ml; p=0.02). Demographical and educational data will be presented. Our findings indicate that serum BNDF levels were significantly decreased in AD patients compared to healthy subjects and this decrease was dependent on cognitive and depressive illness severity. The decrease of BDNF serum levels in AD may reflect a lack of trophic support and thus contribute to progressive degeneration in both diseases.