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Impairment of phagocytic process in macrophages from young and old mice by protein malnutrition
1Departamento de Fisiología Animal, Facultad de Ciencias Biológicas, Universidad Complutense, Madrid, Spain.
Abstract:
In young (15 +/- 2 weeks old) and old (75 +/- 5 weeks old) Swiss mice fed a 4% protein diet ad libitum for 15 days, we studied the different steps of phagocytic processes of peritoneal macrophages. In young mice, adherence to tissue substrates was significantly increased, but spontaneous mobility, chemotaxis, attachment and ingestion of opsonized Candida albicans, and production of superoxide anion indicative of microbicidal capacity measured by the nitroblue tetrazolium (NBT) reduction were significantly decreased with respect to the corresponding young controls (mice fed with a standard 17% protein diet). Attachment and ingestion of C. albicans, and NBT reduction were also decreased in old protein-malnourished mice.
Insights
Protein malnutrition impairs immune cell function in young and old mice. Phagocytic processes, including adherence and microbial killing, were significantly reduced, highlighting the critical role of adequate protein intake for immune defense.
Area of Science:
- Immunology
- Nutrition Science
- Cell Biology
Background:
- Dietary protein is crucial for immune system function.
- Malnutrition can compromise immune cell activity and host defense.
- Age-related changes can exacerbate the effects of malnutrition on immunity.
Purpose of the Study:
- To investigate the impact of protein malnutrition on phagocytic processes in peritoneal macrophages.
- To compare the effects of malnutrition in young versus old mice.
- To assess the microbicidal capacity of macrophages under protein-deficient conditions.
Main Methods:
- Swiss mice (young and old) were fed a 4% protein diet for 15 days.
- Phagocytic functions of peritoneal macrophages were evaluated, including adherence, mobility, and chemotaxis.
- Attachment and ingestion of opsonized Candida albicans were measured.
- Superoxide anion production, assessed by nitroblue tetrazolium (NBT) reduction, was used to indicate microbicidal capacity.
Main Results:
- In young protein-malnourished mice, macrophage adherence increased, but spontaneous mobility, chemotaxis, C. albicans attachment/ingestion, and NBT reduction significantly decreased compared to controls.
- Old protein-malnourished mice also showed decreased attachment and ingestion of C. albicans and reduced NBT reduction.
- Protein deficiency significantly impaired key phagocytic functions and microbicidal capacity in both young and old mice.
Conclusions:
- Protein malnutrition severely compromises the phagocytic functions and microbicidal capacity of macrophages.
- Both young and old mice are susceptible to the detrimental effects of protein deficiency on immune cell function.
- Adequate protein intake is essential for maintaining robust immune defense mechanisms throughout life.