Creatine kinase isoenzymes in healthy newborn foals and preliminary evaluation in septic and in asphyctic animals

Background: Information about the possible role of serum activity of creatine kinase (CK) isoenzymes as a biomarker for septicemia and asphyxia in newborn foals is not available. Objectives: To evaluate the activity of CK isoenzymes in healthy newborns and in septicemic or asphyctic foals. Methods: Electrophoretic separation of CK isoenzymes (CK-MM, CK-MB, CK-BB) and macroenzymes (Macro-CKI and Macro-CK2) was performed on sera from healthy foals sampled 30 minutes after birth, at 3, 12, 24 hours, and daily until day 7. Sera from 9 septicemic and 5 asphyctic foals were also examined at admission and during the follow up. The results were compared with those of age-matched controls. For both healthy and sick foals, differences among the sequential time samplings were also assessed. Results: In healthy foals, total CK activity significantly increased in the first day then decreased on day 2. CK-BB is the main isoenzyme at birth and up to day 7, except at 3 and 12 hours, when CK-MM is the prevalent isoenzyme. CK-MB and macroenzymes are negligible. Compared with age-matched controls, asphyctic foals have increased CK-MM activity, whereas electrophoretic changes in septicemic foals are variable and generally mild. During the follow up, isoenzyme activities normalized in both groups of sick foals. Conclusions: The proportions and activities of the different isoenzymes vary with age, with CK-BB being the main serum isoenzyme in most samplings. Thus it is important to compare the results of sick foals with those of age-matched controls. This comparison reveals severe CK-MM increases in asphyctic foals and variable changes in septicemic foals.