Creatine kinase isoenzymes and macroenzymes in dogs with different neurological diseases

Background: Increased activity of creatine kinase (CK) isoenzymes and macroenzymes, and in particular of the brain isoenzyme (CK-BB) has been reported in dogs with neurological disorders. However, no studies on the possible differences in serum activities of this or other iso- or macroenzymes in different neurological diseases are available Objective: The aim of this study was to describe the electrophoretic distribution of CK iso- and macroenzymes in dogs with neurological disorders in order to assess whether this distribution depends on a specific neurological disease. Methods: This study was done on sera from 45 dogs with neurological diseases (degenerative, n=7; idiopathic epilepsy or IE, n=14; inflammatory, n=16; space occupying lesions or SOL, n=8) and from 10 clinically healthy control dogs. The separation of CK isoenzymes and macroenzymes was performed on sera, using an automated electrophoretic method already validated in dogs. Results: Compared with controls, dogs with neurological disorders had a significantly higher total CK activity and CK-BB activity, and a significantly lower Macro-CK2 activity (P<0.001 for all these comparisons). Comparison of pathological subgroups and controls revealed significant differences (P<0.01) in dogs with IE and inflammatory disorders for total CK activity, in all the subgroups for CK-BB (P<0.01), and in dogs with IE and SOL for Macro-CK2 (P<0.01). Conclusions This suggests that CK-BB is released by neurons damaged by inflammatory or degenerative conditions or due to compressive effects of SOLs. However, the different neurological diseases cannot be differentiated to each other by this approach, unless further studies will define appropriate diagnostic thresholds.