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Erythrocyte membrane Na+ and K+ activated adenosine triphosphatase in protein-calorie malnutrition
Insights
Children with kwashiorkor show higher erythrocyte membrane Na+/K+-ATPase activity, which normalizes with nutritional treatment. Marasmus impacts erythrocyte sodium levels, but not potassium, unlike kwashiorkor.
Area of Science:
- Biochemistry
- Pediatric Nutrition
- Cellular Physiology
Background:
- Protein-calorie malnutrition, including marasmus and kwashiorkor, significantly impacts cellular function.
- Na+ and K+ adenosine triphosphatase (ATPase) is crucial for maintaining cell membrane integrity and ion gradients.
- Erythrocyte Na+ and K+ ATPase activity may serve as a biomarker for nutritional status.
Purpose of the Study:
- To compare Na+ and K+ ATPase activity and ion content in erythrocytes and plasma of malnourished children (marasmus, kwashiorkor) versus healthy children.
- To assess the impact of nutritional rehabilitation on these parameters.
Main Methods:
- Measured total, ouabain-insensitive, and ouabain-sensitive Na+ and K+ ATPase activity in erythrocyte membranes.
- Quantified erythrocyte and plasma Na+ and K+ content.
- Compared enzyme activity and ion levels between malnourished children and healthy controls, and post-treatment.
Main Results:
- Children with kwashiorkor exhibited significantly higher specific activity of ouabain-sensitive Na+ and K+ ATPase compared to controls.
- Marasmic children did not show altered specific activity of this enzyme.
- Nutritional treatment led to a decrease in specific enzyme activity in kwashiorkor patients.
- Kwashiorkor patients showed reduced erythrocyte and plasma K+ content, which improved post-treatment.
- Marasmic children had higher erythrocyte Na+ content compared to controls.
Conclusions:
- Erythrocyte Na+ and K+ ATPase activity is altered in kwashiorkor, suggesting a specific cellular response to this form of malnutrition.
- Nutritional repletion normalizes Na+ and K+ ATPase activity and improves ion balance in kwashiorkor.
- Marasmus presents a different ionic profile, primarily affecting erythrocyte sodium levels.
Abstract:
Total, ouabain insensitive and ouabain sensitive Na+ and K+ adenosine triphosphatase activity in the erythrocyte membrane of protein-calorie malnourished children with marasmus and kwashiorkor was compared with the enzyme activity in apparently healthy children (normals). Na+ and K+ contents of erythrocyte and plasma were also determined in these patients. Specific activity (units per milligram of membrane protein) of ouabain sensitive Na+ and K+ adenosine triphosphatase was significantly higher in erythrocyte membrane preparations from children with kwashiorkor but not from children with marasmus. After 4 to 5 weeks of treatment with diets sufficient in protein and calories the specific activity of the enzyme was lower as compared to that on admission. Erythrocyte and plasma Na+ content (microgram/10(6) cells and microgram per milliliter of plasma) in children with kwashiorkor were not different from those in normal children, however, there was reduction in K+ content of erythrocytes and plasma of these children. After treatment, erythrocyte Na+ and K+ and plasma K+ in children with kwashiorkor increased significantly. In marasmic children erythrocyte Na+ was higher as compared to normal but there were no differences in K+ content of either eyrthrocytes or plasma in these children.