Serum BDNF, TNF-α and IL-1β levels in dementia patientsComparison between Alzheimer’s disease and vascular dementia

Neurotrophins such as the brain-derived neurotrophic factor (BDNF) are reportedly related to the pathogenesis of Alzheimer’s disease (AD). Several studies have revealed an alteration in BDNF expression in the postmortem brains of AD patients. BDNF has great potential as a therapeutic agent because of its ability to cross the blood–brain barrier and due to its wide in vivo distribution. However, little is known about in vivo BDNF in dementia patients. Moreover, the immunological function of neurotrophins such as BDNF has received great interest. Therefore, we investigated the serum levels of BDNF and cytokines such as TNF-α and IL-1β in dementia patients by the enzyme-linked immunosorbent assay (ELISA). The following subjects were included in this study: 60 AD patients, 60 vascular dementia (VaD) patients and 33 healthy controls. AD and VaD patients were matched for age, gender and severity of dementia. Serum BDNF levels in AD patients were significantly lower than those in VaD patients and controls. TNF-α and IL-1β levels showed no significant difference among the three groups. In the dementia groups, neither the TNF-α nor the IL-1β levels correlated with the BDNF levels. Our results suggest that BDNF may play a pathological role in some cases of AD.