Effects of Amino Acid Therapy on Skeletal Muscle in the Acute Catabolic State

Abstract

Following trauma and sepsis, body protein losses emanate almost exclusively from skeletal muscle. This is in contrast to the tissue losses seen during starvation, when the protein losses are equally distributed among all organs excluding the central nervous system. This implies that the speed of the muscle tissue loss is much higher in the acute catabolic state than in starvation, due to the elevated need of substrates in combination with muscle being the only tissue to supply virtually all other tissues with substrates. Conventional nutritional therapy can only partly attenuate this pattern. A hypercaloric support of energy may improve nitrogen balance marginally, but at the expense of lipogenesis, resulting in a gain of adipose tissue during critical illness [ 1 ]. Furthermore, a higher than necessary supply of amino acids or proteins will not improve whole body nitrogen economy beyond what is achieved with a nutritional support designed to meet the measured resting energy expenditure combined with a nitrogen supply of 0.15 g N/kg body weight per day [2].