Hydrolyzed Casein and Whey Protein Supplementation and the Addition of Leucine to Induce Protein Anabolism in Malnourished COPD Patients

Overview

The aim of this study is the first aim of a NIH project that consists of 3 aims. The first aim examines the acute effects of two high-quality milk proteins (casein vs. whey) on whole-body and muscle protein metabolism in COPD patients with severe loss of muscle mass and the effects of adding leucine. The principal endpoints will be the extent of stimulation of net whole body protein synthesis as this is the principal mechanism by which either amino acid or protein intake causes muscle anabolism. After determining the optimal nutritional formulation based on the first aim we will continue to work on the second and third aim where fish oil supplementation will be part of the nutritional intervention as well.

Cachectic COPD patients are characterized by a decreased muscle protein synthesis and an elevated myofibrillar protein breakdown. A substantial number of these patients, characterized by an enhanced systemic inflammatory response, fails to respond to nutritional therapy, which is of clinical relevance as weight gain to nutritional therapy is a significant, independent predictor of mortality in COPD. In the present study, the acute protein anabolic effect of two high-quality milk protein supplements in COPD will be examined by comparing a hydrolyzed casein and whey protein meal. We make use of hydrolyzed proteins to correct for absorption differences. Furthermore the effects of these milk proteins with or without enrichment of leucine will be investigated. Variables of interest are: net whole body protein synthesis; whole body protein synthesis and breakdown rate; whole body myofibrillar protein breakdown rate; whole body collagen breakdown; kinetics of insulin; glucose; amino acid levels. It is the investigators hypothesis that a nutritional supplement containing casein protein and high levels of leucine will target the metabolic alterations of these cachectic COPD patients and will specifically stimulate protein anabolism. The knowledge gained from this study will benefit our insight in terms of promotion of protein anabolism in COPD patients. The long-term goal is to reformulate nutritional composition in accord with the effects of COPD on protein metabolism in order to ameliorate or even prevent progressive muscle wasting in these subjects, and improve their quality of life and survival rates.