Related Experiment Videos
Lipid peroxidation can be reduced in infants on total parenteral nutrition by promoting fat utilisation
1Institute of Child Health and Great Ormond Street Hospital for Children, University College London Medical School, England.
Insights
Reducing the carbohydrate-fat ratio in total parenteral nutrition (TPN) in infants can decrease harmful free radical production by increasing fat utilization, similar to stopping fat infusion.
Area of Science:
- Biochemistry
- Pediatric Nutrition
- Metabolic Research
Background:
- Infants receiving total parenteral nutrition (TPN) exhibit increased oxygen-derived free radical activity.
- This activity is specifically linked to the infusion of fats during TPN.
Purpose of the Study:
- To investigate if increasing fat utilization during TPN can reduce oxygen-derived free radical production.
- To test the hypothesis that enhanced fat metabolism mitigates oxidative stress in infants on TPN.
Main Methods:
- Two experiments were conducted: Experiment A adjusted carbohydrate infusion while keeping fat constant; Experiment B adjusted fat infusion while keeping carbohydrate constant.
- Fat utilization was measured using indirect calorimetry.
- Plasma malondialdehyde (MDA) levels, an indicator of lipid peroxidation and free radical activity, were quantified via a colorimetric assay.
Main Results:
- Metabolic stability was confirmed by consistent oxygen consumption, carbon dioxide production, and resting energy expenditure in both experiments.
- Experiment A showed a significant increase in fat utilization (P = .0005) and a significant decrease in MDA concentration (P = .009).
- Experiment B also demonstrated a significant decrease in MDA concentration (P = .007), with similar reductions observed between both experiments.
Conclusions:
- Reducing free radical production during TPN does not necessitate the complete cessation of fat infusion.
- Enhancing fat utilization by adjusting the carbohydrate-to-fat ratio in TPN significantly reduces free radical activity.
- These findings offer crucial insights for optimizing TPN composition in infants to minimize oxidative stress.
Background/Purpose:
Increased oxygen-derived free radical activity has been reported during total parenteral nutrition (TPN) in infants and has been specifically linked to the fat infusion. The aim of this study was to test the hypothesis that during TPN, oxygen-derived free radical production can be reduced by increasing the utilisation of fat.
Methods:
In experiment A (17 patients) the fat infusion was kept constant (3 g/kg/d) and the carbohydrate infusion was changed from 18 g/kg/d on day 1 to 10 g/kg/d on day 2. In experiment B (six patients) the carbohydrate infusion remained constant and the fat infusion was changed from 3 g/kg/d on day 1 to 0 g/kg/d on day 2. Fat utilisation was measured by indirect calorimetry. Plasma malondialdehyde, an index of lipid peroxidation resulting from increased oxygen-derived free radical activity, was measured by a colorimetric assay.
Results:
In both experiments there was no significant change between the two study phases in oxygen consumption, carbon dioxide production, and resting energy expenditure demonstrating that the patients were metabolically stable. In experiment A there was a significant (P = .0005) increase in fat utilisation and a significant (P = .009) decrease in malondialdehyde (MDA) concentration between the two phases. In experiment B there was also a significant (P = .007) decrease in MDA concentration. The decrease in MDA concentration was similar between the two experiments.
Conclusions:
It is not necessary to stop the infusion of fat to reduce free radical production. Promoting fat utilisation by reducing the carbohydrate-fat ratio of the TPN reduces free radical activity to a similar extent as fat exclusion. These findings have important implications for the composition of TPN.