ASPECTS OF CARDIOMYOPATHY ARE EXACERBATED BY ELEVATED DIETARY-FAT IN COPPER-RESTRICTED RATS

The objective of this study was to determine if a high fat diet having a 2:1 saturated:polyunsaturated fatty acid ratio exacerbates signs of copper deficiency. Male weanling Long-Evans rats were randomly placed into one of the following treatment groups: adequate copper low fat, adequate copper high fat, deficient copper low fat or deficient copper high fat. The levels of fat used were 31 or 12% of daily energy, and copper concentrations were 94.5 mu mol/kg and <15.8 mu mol/kg in the c opper-adequate and copper-deficient diets, respectively. Cardiac hyper trophy as well as lower liver copper levels and superoxide dismutase a ctivity were observed in both groups of copper-deficient rats. Irrespe ctive of copper level, consumption of the high fat diet resulted in th ickening of the interventricular septum and left ventricular free wall . Electrocardiograms revealed that the copper-deficient high fat diet led to a significantly smaller QT interval compared with all other gro ups. Significantly greater S-wave voltage due to copper deficiency was observed. Significantly lower heart cytochrome c oxidase (CCO) activi ty was found in the copper-deficient groups with the copper-deficient high fat group showing the lowest activity. Western blots of the cardi ac non-myofibrillar fraction demonstrated lower amounts of CCO nuclear encoded peptides in the copper-deficient groups, with the least amoun t seen in the copper-deficient high fat treatment. These data suggest that a high level of dietary fat exacerbates some of the signs of copp er deficiency.