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Uptake of ascorbic acid by human neutrophils
1Department of Nutritional Sciences, University of California, Berkeley 94720.
Nutrition Reviews
|November 1, 1993
Summary
Human neutrophils protect themselves from bacterial oxidants by taking up ascorbic acid. They oxidize it to dehydroascorbic acid, then re-reduce it inside the cell for sustained antioxidant defense.
Area of Science:
- Biochemistry
- Cell Biology
- Immunology
Background:
- Human neutrophils generate reactive oxygen species during bacterial infections.
- These oxidants pose a risk of self-damage to neutrophils.
- Intracellular antioxidant mechanisms are crucial for neutrophil survival.
Purpose of the Study:
- To elucidate the mechanism by which neutrophils protect themselves from self-inflicted oxidative damage.
- To investigate the role of ascorbic acid in neutrophil antioxidant defense.
Main Methods:
- The study focused on the biochemical pathways of ascorbic acid metabolism in neutrophils.
- Ascorbic acid and dehydroascorbic acid uptake and redox cycling were analyzed.
Main Results:
- Neutrophils actively transport extracellular ascorbic acid by first oxidizing it to dehydroascorbic acid.
- Dehydroascorbic acid is rapidly internalized and reduced back to ascorbic acid intracellularly.
- This process maintains a high intracellular concentration of ascorbic acid (10-20 mmol/L).
Conclusions:
- Neutrophils employ an efficient ascorbic acid redox cycle for self-protection against bacterial oxidants.
- This mechanism ensures sustained intracellular antioxidant capacity, vital for neutrophil function and survival.