COPPER DEFICIENCY ALTERS COLLAGEN TYPES AND COVALENT CROSS-LINKING INSWINE MYOCARDIUM AND CARDIAC VALVES

Dietary copper deficiency induces alterations of connective tissue met abolism that are associated with lesions in cardiovascular and other o rgan systems. To determine the impact of copper deficiency on characte ristics of collagen in porcine myocardium and cardiac valves, weaned p igs were fed diets with adequate or deficient levels of copper. Althou gh dietary copper did not affect the concentration of collagen in eith er myocardium or bicuspid valves, the degree of collagen cross-linking , as assessed by the level of hydroxylysylpyridinoline, was lower in b oth tissues of copper-deficient pigs. Proportions of type III collagen were increased in the left ventricle and bicuspid valves of copper-de ficient pigs. Copper deficiency induced extensive remodeling, however, of the collagen fraction of cardiac interstitium. Reduction in left v entricular collagen cross-linking may provide the stimulus for the dev elopment of cardiac hypertrophy, which characterizes severe copper def iciency, by increasing the compliance of the ventricular wall. The shi ft in the phenotypic profile of collagen that is associated with this cardiac hypertrophy indicates synthesis of new collagen, which could a ffect collagen cross-linking irrespective of copper status.