Serum Fatty Acid Compositions in Dogs with Mitral Insufficiency

抄録

Fatty acids are a major source of energy in the normal myocardium and are taken up passively from the bloodstream. However, with heart failure, the use of fatty acids decreases in the myocardium. Therefore, serum fatty acid concentrations in dogs with mitral insufficiency (MI) might differ from those in normal dogs. The present study was designed to determine the serum fatty acid compositions in dogs with different severities of MI according to the classification proposed by the International Small Animal Cardiac Heart Council (ISACHC) and to elucidate the relationships between the determined compositions and echocardiographic parameters. In total, 30 dogs with MI were divided into 3 groups (I, II, and III) according to the ISACHC classification of MI severity. The healthy group consisted of 12 dogs matched with the MI groups for age and body weight. The serum concentrations of 13 fatty acids were measured by gas chromatography. The levels of linoleic acid (LA), docosatetraenoic acid (DTA), and arachidonic acid (AA) in group I were significantly lower than those in the healthy group (p<0.05). The levels of eicosapentaenoic acid (EPA) and AA in group II were significantly lower than those in the healthy group (p<0.05). The level of EPA in group III was significantly lower than that in the healthy group (p<0.05). In addition, the ratio of EPA to AA levels (EPA/AA ratio) in group III was significantly lower than that in the healthy group (p<0.05). With regard to the relationships between fatty acid concentrations in all MI groups (I through III) and echocardiographic parameters, the levels of AA and DTA showed a significant positive correlation with the ratio of left ventricular end-diastolic internal diameter to aortic diameter (LVIDd/Ao ratio) (AA, r=0.396 and p=0.048; DTA, r=0.426 and p=0.027). In addition, the docosapentaenoic acid (DPA) level correlated negatively with fractional shortening (r=-0.437 and p=0.023). Furthermore, the EPA/AA ratio correlated negatively with the ratio of left atrial to aortic diameters (r=-0.383 and p=0.048). The fatty acid concentrations and ratios in the dogs with 3 types of MI according to the ISACHC classification differed from those in healthy dogs. Some of these concentrations and ratios correlated with echocardiographic parameters.