Macrophages Acid hydrolases

One is led to consider both the reason for the increased activities of these protein-degrading enzymes in diseased muscle and also their possible importance in the process of muscle atrophy. Acid and alkaline cathepsins may require separate consideration in respect to both of these questions. A number of other acid hydrolases, like acid cathepsin, display elevated activity in diseased muscle such enzymes- are probably also lysosomal, and the increase in their activity may signify increased numbers of lysosomes in diseased muscle. The suggestion frequently has been made that the increase in acid cathepsin and other hydrolases is a result of the macrophage invasion of the muscle, but Weinstock and his col-... 

In vitamin E-deficient rabbits, the activity of creatine phosphokinase increases, apparently in muscle first and in blood later. The administration of a-tocopherol normalizes the serum CPK levels. Because ethi-onine mimicks this effect of vitamin E, it has been proposed that vitamin E acts as a repressor of the gene responsible for the biosynthesis of creatine phosphokinase. It was also proposed that a similar mechanism could explain the increase in acid hydrolases observed in muscles of vitamin E-deficient animals. In the latter case, such an interpretation is unlikely because the appearance of the hydrolase is associated with the appearance of macrophages. 

It is important to note that most of the results were obtained by treating animals with C. parvum before, simultaneously or just after the inoculation of tumor cells, although in one report (Fisher et al., 1975) antitumor effects of C. parvum were observed on well-implanted tumors. The antitumor effects were shown to be associated with the stimulation of cell-mediated immunity macrophage numbers were increased, their chemotaxis was enhanced, as well as the secretion of lysosomal acid hydrolase (Wilkinson,... 

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