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Energy metabolism in infants with cystic fibrosis
Julie E Bines1, Helen D Truby, David S Armstrong
1Department of Gastroenterology and Clinical Nutrition, Royal Children's Hospital, Parkville, Victoria, Australia.
Insights
Infants with cystic fibrosis (CF) show growth impairment due to pancreatic insufficiency, not a defect in energy metabolism. Energy expenditure is not elevated, even with minimal lung disease.
Area of Science:
- Pediatric Gastroenterology
- Metabolic Research
- Genetic Disorders
Background:
- Cystic Fibrosis (CF) is a genetic disorder affecting multiple organs.
- Early diagnosis and intervention are crucial for managing CF in infants.
- Understanding energy metabolism in infants with CF is key to addressing growth impairments.
Purpose of the Study:
- To investigate potential defects in energy metabolism in infants diagnosed with Cystic Fibrosis (CF).
- To correlate energy expenditure and intake with CF genotype and pancreatic status.
- To determine if lung disease severity impacts energy expenditure in CF infants.
Main Methods:
- Measured resting energy expenditure (REE) and total energy expenditure (TEE) in infants with CF and healthy controls.
- Calculated metabolizable energy intake (MEI) and assessed body composition.
- Determined CFTR genotype (Delta F508) and pancreatic sufficiency in CF infants; some underwent bronchial lavage.
Main Results:
- Infants with CF at diagnosis exhibited anthropometric deficits linked to pancreatic insufficiency.
- No significant increase in REE, TEE, or MEI was found in CF infants compared to controls.
- Energy metabolism was not correlated with Delta F508 genotype, pancreatic status, or the presence of lung infection/inflammation.
Conclusions:
- Growth impairment in early infancy with CF is primarily linked to pancreatic insufficiency.
- No evidence suggests a primary defect in energy metabolism in infants with CF related to the Delta F508 mutation.
- Minimal lung disease in CF infants does not appear to be associated with increased energy expenditure.
Objective:
To determine whether a defect in energy metabolism exists in infants with cystic fibrosis (CF).
Design:
Unselected, newly-diagnosed subjects with CF (n = 46) and 24 healthy infants aged <20 weeks had measurements of resting energy expenditure (REE), total energy expenditure (TEE) (n = 25), and body composition. Metabolizable energy intake (MEI) was calculated. Genotype, energy intake, and pancreatic status was determined in all subjects with CF, and 24 underwent bronchial lavage.
Results:
At diagnosis, infants with CF detected by newborn screening had significant anthropometric deficits (mean [SD] z-weight = 0.5 [1.0], z-length = 0.7 [1.3]) associated with pancreatic insufficiency. Their REE, TEE, or MEI (absolute measurements, per unit body weight or fat-free mass) were not increased. No relationship between REE, TEE, or MEI and Delta F(508) genotype, and no proportional differences in individual components of MEI between subjects with CF and controls, or between subjects with CF who were homozygotes or compound heterozygotes for Delta F(508) were observed. REE and TEE were not correlated with bronchial infection or inflammation.
Conclusion:
Growth impairment during the first weeks of life in infants with CF is associated with pancreatic insufficiency. However, there is no evidence for a defect of energy metabolism related to Delta F(508), and in infants with CF, minimal lung disease is unaccompanied by increased energy expenditure.