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.
