Markers of oxidative stress in dogs with heart failure.

We tested the hypothesis that indirect measures of oxidative stress (vitamin E, glutathione peroxidase, and malondialdehyde) differ in dogs in heart failure resulting from either myxomatous mitral valve disease or dilated cardiomyopathy. Dogs were classified according to the International Small Animal Cardiac Health Council (ISACHC) classification. Additionally, the effect of cardiac therapy on oxidative stress parameters and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in advanced stages of congestive heart failure was investigated. There were no significant differences in oxidative stress parameters between healthy dogs and the individual groups of cardiac patients. Significantly lower malondialdehyde (MDA) was observed in the ISACHC II group in comparison to ISACHC groups III and I. A significant positive correlation in treated patients was observed between NT-proBNP and MDA, NT-proBNP and vitamin E, as well as between MDA and vitamin E (and lipid-standardized vitamin E). No significant differences in any of the measured parameters were found between treated and non-treated cardiac patients. Our results suggest an association between MDA (the extent of lipid peroxidation) and NT-proBNP, vitamin E and NT-proBNP, as well as between MDA and vitamin E in treated canine patients. Plasma vitamin E concentration was maintained in all stages of cardiovascular disease in these canine patients.