Relevance of COX-2 gene expression in dementia with lewy bodies associated with Alzheimer pathology

The aim of the present study was to investigate whether cyclooxygenase-2 (COX-2) expression is involved in the pathogenesis of neurodegeneration in dementia with Lewy bodies (DLB) by measuring COX-2 mRNA and protein expression in frontal cortex and substantia nigra pars compacta of DLB and control human brains. DLB cases were classified as pure form or common form according to the absence or the presence of Alzheimer pathology including neurofibrillary tangles and amyloid deposits by Braak staging. Using Western Blot and Real-time Polymerase chain reaction (PCR) analysis, we have shown that cortical COX-2 protein levels were decreased in DLB cases (P < 0.01). However, no differences in nigral COX-2 mRNA expression were observed between control and DLB cases. In conclusion, the present results suggest that in DLB nigral COX-2 mRNA expression does not correlate with dopaminergic neurodegeneration and that the slight changes observed in the common type are probably due to the concomitant AD pathology.