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Transferrin kinetics are altered in children with severe protein-energy malnutrition
J F Morlese1, T Forrester, M Del Rosario
1U.S. Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
Insights
Plasma transferrin (Tr) concentration in children with protein-energy malnutrition (PEM) is primarily regulated by synthesis rate, with infections playing a minor role. Tr levels are not a reliable indicator of overall protein status in these children.
Area of Science:
- Nutritional Biochemistry
- Pediatric Nutrition
- Metabolic Regulation
Background:
- Protein-energy malnutrition (PEM) significantly impacts plasma protein levels, including transferrin (Tr).
- Understanding the kinetics of Tr concentration changes is crucial for assessing nutritional status in pediatric populations.
- The influence of concurrent infections on Tr metabolism in malnourished children requires further elucidation.
Purpose of the Study:
- To investigate the kinetic mechanisms behind plasma Tr concentration changes in children with PEM.
- To determine the extent to which infections contribute to altered Tr levels during malnutrition.
- To evaluate the correlation between plasma Tr concentration and body protein status in malnourished children.
Main Methods:
- Utilized a constant intragastric infusion of 2H3-leucine to measure plasma Tr concentration, fractional synthesis rate (FSR), and absolute synthesis rate (ASR).
- Studied 14 children with PEM at multiple time points: early admission, after infection control, and during recovery.
- Assessed correlations between plasma Tr concentrations and established indices of wasting.
Main Results:
- Children with PEM exhibited lower Tr concentrations and synthesis rates compared to recovery levels.
- Plasma Tr concentration increased when infections were controlled, but Tr synthesis rates remained unchanged.
- Correlations between plasma Tr concentrations and indicators of wasting were only fair (P < 0.05).
Conclusions:
- Plasma Tr pool size in malnourished children is mainly modulated by alterations in its synthesis rate.
- Infections have a limited impact on reducing the Tr pool, affecting catabolism or intravascular loss minimally.
- Plasma Tr concentration is an unreliable biomarker for assessing protein nutritional status in children with PEM.
Abstract:
This study was undertaken to determine the following: 1) the kinetic changes responsible for the depletion and repletion of plasma transferrin (Tr) concentration in children with protein-energy malnutrition (PEM); 2) the role of infection in mediating these changes; and 3) whether plasma Tr concentration is related to body protein status. We measured plasma Tr concentration, and fractional (FSR) and absolute (ASR) Tr synthesis rates with the use of a constant intragastric infusion of 2H3-leucine in 14 children with PEM, at 2 d postadmission (study 1), 8 d postadmission when infections were under control (study 2), and at recovery (study 3). In studies 1 and 2, the children synthesized less Tr and had lower Tr concentrations compared with values at recovery. When infections were controlled, plasma Tr concentration rose, but Tr synthesis was unchanged. There were only fair correlations (P < 0. 05) between plasma Tr concentrations and indices of wasting. Concerning malnourished children, we reached the following conclusions: 1) changes in the Tr pool size are achieved mainly through changes in synthesis rate; 2) infections play a minor role in reducing the Tr pool through either changes in the rate of catabolism or loss from the intravascular space; and 3) Tr concentration is not a very good indicator of protein nutritional status.