Enhancement of fatty acid mobilization and oxidation by glucose-xylitol compared to glucose alone in posttraumatic and septic patients.
INTRODUCTION: The objective of this study was to provide further information about the influence of xylitol on glucose and fatty acid metabolism after trauma and during sepsis. METHODS: In study I 18 metabolically normal patients undergoing coronary artery bypass grafting operation were randomly assigned into three groups. Group I (C I, n = 6) received 2 mg/kgBW/min of glucose, group II (C II, n = 6) 2 mg/kgBW/min of a glucose/xylitol mixture (1:1) and group III (C III, n = 6) 1 ml/kgBW/min of an isotonic saline solution. Infusions were applied over a 24-h-period following operation. Concentrations of glucose, lactate, insulin and single free fatty acids were measured before and after surgery and at 6-h-intervals over 36 hours postoperatively. In study II 5 septic patients were intravenously given 4 mg/kgBW/min glucose over a 6-h-period. Energy supply was then changed to a glucose/xylitol (1:1) regimen in an equicaloric dosage of 4 mg/kgBW/min for six hours again. Hepatic glucose production ([6,6-d2]-glucose), palmitate oxidation ([1-13C]-palmitate) and lactate concentrations were analyzed at the end of each infusion regime with the help of stable isotope technique and an enzymatic test, respectively. RESULTS: In study I glucose and insulin concentrations in C II and III were significantly lower than in C I during the postoperative infusion period. Highest lactate concentrations were measured in C I after 6 hours of infusion. Free fatty acids in C I remained at significantly lower levels compared to C II and III until glucose infusion was stopped. In septic patients (study II) xylitol led to significant lower hepatic glucose production rates and lactate concentrations than glucose, whereas palmitate oxidation increased. CONCLUSIONS: During the acute phase after trauma and during sepsis a carbohydrate supplementation with xylitol was superior to glucose alone because high plasma glucose concentrations were avoided, highly energy consuming hepatic glucose production was reduced and the release and oxidative utilization of free fatty acids was enhanced.