Oxidation of cytosolic proteins and expression of creatine kinase BB in frontal lobe in different neurodegenerative disorders

The presence of the biomarkers of oxidative damage, protein carbonyl formation and the inactivation of oxidatively sensitive brain creatine kinase (CK BE, cytosolic isoform), were studied in frontal lobe autopsy specimens obtained from patients with different age-related neurodegenerative diseases: Alzheimer's disease (AD), Pick's disease (PkD), diffuse Lewy body disease (DLBD), Parkinson's disease (PD), and age-matched control subjects. The CK activity was significantly reduced in the frontal lobe of AD, PkD and DLBD subjects, and CK BB-specific mRNA was significantly reduced in AD and DLBD. Protein carbonyl content was significantly increased in AD, PkD and DLBD. The results of this study confirm that the presence of biomarkers of oxidative damage is related to the presence of histopathological markers of neurodegeneration. Our data suggest that oxidative damage contributes to the development of the symptoms of frontal dysfunction in AD, PkD and DLBD. The development of frontal dysfunction in idiopathic PD might be secondary to oxidative damage and neuronal loss primarily located in the nigrostriatal system. The results of CK BE expression analysis demonstrate that the loss of the isoenzyme in different neurodegenerative diseases is likely the consequence of its posttranslational modification, possibly oxidative damage. Changes in CK BE expression may be an early indicator of oxidative stress in neurons.