Dietary iron deficiency results in cardiac eccentric hypertrophy in rats

This study reports the presence of eccentric cardiac hypertrophy in rats made anemic by feeding an iron-deficient diet. Male weanling Sprague-Dawley rats were provided free access to diets either adequate (n=9) or inadequate in iron (n=8) for a period of 7 weeks from weanling or until 10 weeks of age. At that time, blood was obtained for hematocrit and hemoglobin determination, and liver and hearts were collected for further analysis. Liver non-heme iron levels confirmed that the rats were iron-deficient, and the very low hematocrit and hemoglobin values revealed the presence of physiological anemia. Despite the lighter body weights in the iron-deficient rats, this group had greater absolute heart weights and heart:body weight, clearly demonstrating the presence of cardiac hypertrophy. Iron-deficient rats had elevated heart rates but lower norepinephrine levels than control rats. Sagittal sectioning of all hearts allowed for the measurements of the wall thicknesses, lumen volume, and width dimensions. Results revealed significantly greater left ventricular lesser diameter, apical thickness, and left ventricular volume in hearts from iron-deficient rats compared to iron-adequate rats. The hypertrophy pattern present in iron-deficiency anemia is in contrast to other nutritional models of hypertrophy, such as copper-deficiency, where a concentric hypertrophy occurs both in the presence and absence of anemia.