Human Metabolism of HMB

Statins are a class of drugs that are the most commonly prescribed medications in developing countries. Statins act on the enzyme HMG-CoA reductase to inhibit its conversion to mevalonate, a precursor for cholesterol synthesis. Subsequently statins are prescribed to patients with relatively high blood cholesterol levels. However, taking statins does not come without side effects. Most notably, the effects of statins on muscle wasting have been studied extensively. This includes up-regulation of the ubiquitin proteasome system, muscle cell damage and rhabdomyolysis, elevated creatine kinase, and mitochondrial dysfunction. Due to the negative side effects of statin therapy, additional therapies are warranted to help offset the effects on muscle wasting.

Loss of muscle mass is a significant concern as it is associated with a reduction in muscle strength and power (Ferrando et al., 1996; Creditor, 1993). This condition is observed in aging, disease states, and long periods of unloading such as hospital admission and can lead to disability, increased falls, loss of independence, and mortality. Subsequently, there is a critical need to develop interventions to counteract this loss of muscle mass and strength. Exercise is one such intervention, however, in some cases may not be a feasible option. For instance, exercise has been demonstrated to exacerbate the muscle side of effects of statins. Subjects complain of increased muscle soreness and have elevated creatine kinase levels and they also do not want to take statins anymore (Kearns et al., 2008; Parker et al., 2012; Sinzinger et al., 2004). Because of this limitation, there is a critical need to develop other interventions that can prevent the loss of muscle mass during statin use.