Brain-derived neurotrophic factor in patients with frontotemporal dementia

Brain-derived neurotrophic factor (BDNF) promotes survival and growth of va rious nerve cell populations during normal development and following differ ent insults in the developing and adult brain. BDNF expression is reduced i n Alzheimer disease, but little is known about BDNF expression in other typ es of dementia. Frontotemporal dementia (FTD) is a common cause of mental i mpairment in old age, which is characterized by neuron loss in the upper co rtical layers mainly of the frontal and temporal cortex. BDNF protein expre ssion has been examined by Western blotting and immunohistochemistry in the cerebral cortex of individuals affected by FTD. Examination of pathologica l samples (n = 8, mean age: 74.7 years; four men, four women) was conducted in parallel with corresponding samples from age-matched controls (n = 8; m ean age: 72.6 years; three men, five women). Post-mortem delay was between 2 and 6 h. Preserved BDNF expression, as revealed by Western blotting, has been observed in the frontal and temporal cortices of patients with FTD. Fu rthermore, immunohistochemistry has disclosed maintained BDNF immunoreactiv ity in surviving neurons of the upper cellular layers, as well as in neuron s of the inner cellular layers in FTD. These results show that FTD is not a ssociated with a decay of BDNF in cortical neurons, and therefore, that BDN F is differentially regulated in diseases causing dementia. (C) 2000 Elsevi er Science ireland Ltd. All rights reserved.