Enlargement of Mitochondrial Compartment in Iron and Copper Deficiency

Marked enlargement of the mitochondrial compartment is present in heart muscle, liver, and erythroblasts of iron- and copper-deficient rats. Mitochondria are increased in size, and may also be increased in number, particularly in heart muscle and erythroid cells. The enlarged mitochondria are more electron-lucent and in the hepatocyte may have sparser packing of cristae than in animals on a complete diet. Morphologic changes in the erythroid percursors of three iron-deficient patients are similar to those observed in the experimental animal. The morphologic response is not attributable to anemia or inanition but appears more specifically related to the lack of trace metals or cofactors required for the synthesis of certain mitochondrial enzymes.