Serum creatine kinase isoenzymes and macroenzymes in dogs with different neurologic diseases

Background: Increased serum activity of CK isoenzymes and macroenzymes, and in particular of the brain isoenzyme (CK-BB) has been reported in dogs with central nervous system (CNS) disorders. However, no studies on the possible differences in serum activities of CK iso- or macroenzymes (Macro-CK1 and Macro-CK2) in different neurologic diseases are available. Objective: The aim of this study was to describe the electrophoretic distribution of CK iso- and macroenzymes in dogs with CNS disorders in order to assess whether this distribution depends on a specific neurologic disease. Methods: This study was done on sera from 45 dogs with neurologic diseases (degenerative, n = 7; idiopathic epilepsy [IE], n = 14; inflammatory, n = 16; space occupying lesions [SOL], n = 8) and from 10 clinically healthy dogs. The separation of serum CK isoenzymes and macroenzymes was performed using an automated electrophoretic method already validated in dogs. Results: Compared with healthy dogs, dogs with CNS disorders had significantly higher total CK and CK-BB activities, and a significantly lower Macro-CK2 activity (P <.001). Comparison of pathologic subgroups and healthy dogs revealed significant differences (P <.01) in dogs with IE and inflammatory disorders for total CK activity, in all the subgroups for CK-BB (P <.01), and in dogs with IE and SOL for Macro-CK2 (P <.01). Conclusions: The results of this study suggest that CK-BB is released by neurons damaged by inflammatory or degenerative conditions or due to compressive effects of SOL. However, the neurologic diseases cannot be differentiated based on CK-BB or Macro-CK2 activities, unless further studies allow the definition of diagnostic thresholds.