Protein metabolism in cystic fibrosis: responses to malnutrition and taurine supplementation.
Increased protein breakdown has been cited as an important cause of nutrient loss in cystic fibrosis (CF). Taurine deficiency, which is common in CF, may contribute to the increased breakdown. The occurrence of and the benefit of taurine supplementation to abnormal protein metabolism in apparently optimally treated CF were assessed using a 12-mo double-blind crossover technique in 14 well-nourished and seven mildly-moderately malnourished infection-free preadolescent CF children. Muscle protein breakdown (urinary 3-methylhistidine technique) was significantly decreased in well-nourished (1.35% degraded/24 h +/- 0.15, p less than 0.05) and malnourished (1.24 +/- 0.11, p less than 0.001) CF children compared with controls (1.50 +/- 0.17, n = 13). Whole-body protein flux, synthesis, and catabolism ([15N]-glycine technique) were similar in all groups. Net protein gain was greater in CF children, particularly those who were well-nourished (0.55 g/(kg X 10 h) +/- 0.35, p less than 0.01) compared with controls (0.16 +/- 0.26). Taurine supplementation did not significantly affect any of the indices. In the absence of infection, protein metabolism in CF children responds appropriately to malnutrition.
Thompson
G N
GN
Department of Chemical Pathology, Adelaide Children's Hospital, South Australia.
Tomas
F M
FM
D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications / Q000378:metabolism*; D004032:Diet; D004044:Dietary Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009132:Muscles / Q000378:metabolism; D011488:Protein Deficiency / Q000150:complications* / Q000178:diet therapy / Q000378:metabolism; D013654:Taurine / Q000008:administration & dosage* / Q000172:deficiency / Q000378:metabolism
D004044:Dietary Proteins; D013654:Taurine