Related Experiment Videos
Protein metabolism kinetics in neonates: effect of intravenous carbohydrate and fat
M O Jones1, A Pierro, P J Garlick
1Department of Paediatric Surgery, Alder Hey Children's Hospital, Liverpool, UK.
Insights
Different glucose/fat ratios in total parenteral nutrition (TPN) did not significantly alter protein metabolism kinetics in newborn infants. This study found similar nitrogen balance, protein flux, synthesis, breakdown, and oxidation rates across varying macronutrient compositions.
Area of Science:
- Nutritional Science
- Neonatalogy
- Metabolic Research
Background:
- Total parenteral nutrition (TPN) is crucial for neonates unable to achieve enteral feeding.
- Optimizing TPN composition is vital for infant growth and metabolic stability.
- Understanding macronutrient effects on protein metabolism in neonates is essential.
Purpose of the Study:
- To investigate the impact of varying glucose and fat ratios in TPN on protein metabolism kinetics in newborn infants.
- To compare protein metabolism parameters between two distinct TPN regimens with different macronutrient profiles.
- To assess nitrogen balance and protein turnover rates under controlled TPN conditions.
Main Methods:
- A study involving 14 newborn infants receiving TPN over a 3-day period.
- Two groups received different glucose/fat ratios (Group A: 10.0g/kg/d dextrose, 4.0g/kg/d fat; Group B: 19.0g/kg/d dextrose, 0.5g/kg/d fat) with constant calories and amino acids.
- Protein metabolism kinetics were assessed using [13C]leucine infusion, urinary nitrogen excretion, indirect calorimetry, and gas chromatograph mass spectrometry.
Main Results:
- No significant differences were observed between the groups in nitrogen balance (0.27 g/kg/d), total protein flux (10.38 g/kg/d), total protein synthesis (9.64 g/kg/d), total protein breakdown (7.86 g/kg/d), or total protein oxidation/excretion (0.92 g/kg/d).
- Infant characteristics (weight, gestational age, postnatal age) were similar between the study groups.
- Caloric and amino acid intake were standardized across all infants.
Conclusions:
- The glucose/fat ratio in TPN, within the tested ranges, does not appear to significantly influence protein metabolism kinetics in newborn infants.
- These findings suggest flexibility in TPN formulation regarding glucose and fat, provided caloric and amino acid needs are met.
- Further research may explore other metabolic outcomes or different TPN compositions.
Abstract:
The aim of this study was to determine the effect of different glucose/fat ratios on protein metabolism kinetics in newborn infants receiving total parenteral nutrition (TPN). Eighteen studies were done on 14 infants receiving TPN (weight 3.15 +/- 0.22 kg [mean +/- SEM]; gestational age 37.8 +/- 0.9 weeks; postnatal age 14.0 +/- 3.7 days). There were two study groups. Group A infants (n = 9) received 10.0 g/kg/d of dextrose and 4.0 g/kg/d of fat; group B infants (n = 9) received 19.0 g/kg/d of dextrose and 0.5 g/kg/d of fat. Caloric intake (86 kcal/kg/d) and amino-acid intake (2.5 g/kg/d) were the same in the two groups. There was no difference between the groups with regard to weight, gestational age, and postnatal age. Intravenous diet was constant during the 3-day study period. Timed urinary nitrogen excretion was determined. On day 3 of the study, each infant received a priming dose of 15 mumol/kg of [13C]leucine followed by a 6-hour infusion at 6 mumol/kg/h. Plasma and breath samples were taken at hourly intervals, and CO2 production was measured by indirect calorimetry. Plateau levels of plasma [13C]-alpha Ketoisocaproic acid (KIC) enrichment and expired 13CO2 enrichment were determined by gas chromatograph mass spectrometry. Protein metabolism kinetics were calculated. Results were: nitrogen balance 0.27 +/- 0.01 g/kg/d, total protein flux 10.38 +/- 0.34 g/kg/d, total protein synthesis 9.64 +/- 0.31 g/kg/d, total protein breakdown 7.86 +/- 0.38 g/kg/d, and total protein oxidation/excretion 0.92 +/- 0.04 g/kg/d.(ABSTRACT TRUNCATED AT 250 WORDS)