Creatine downregulated de novo creatine synthesis
Creatine is not included in commercial pediatric parenteral products; the entire creatine requirement must be met by de novo synthesis from arginine during parenteral nutrition (PN). Poor arginine status is common during PN in neonates, which may compromise creatine accretion. We hypothesized that creatine supplementation will improve creatine status and spare arginine in PN-fed piglets. Piglets (3-5-day (d) old) were provided PN with or without creatine for 14 d. Tissue concentrations of creatine metabolites and activities of creatine-synthesizing enzymes, as well as tissue protein synthesis rates and liver lipid parameters, were measured. Creatine provision lowered kidney and pancreas L-arginine:glycine amidinotransferase (AGAT, EC number 18.104.22.168) activities and plasma guanidinoacetic acid (GAA) concentration, suggesting the downregulation of de novo creatine synthesis. Creatine increased plasma creatine concentrations to sow-fed reference levels and increased the creatine concentrations in most tissues, but not in the brain. PN creatine resulted in greater protein synthesis in the liver and the kidney, but not in the pancreas, skeletal muscle, or gut. Creatine supplementation also reduced liver cholesterol concentrations, but not triglyceride or total fat. The addition of creatine to PN may optimize the accretion of creatine and reduce the metabolic burden of creatine synthesis in rapidly growing neonates.
Dinesh OC, Bertolo RF, Brunton JA. Creatine supplementation to total parenteral nutrition improves creatine status and supports greater liver and kidney protein synthesis in neonatal piglets. Pediatr Res. 2018 Jan;83(1-1):135-141.