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Effect of respiratory infection on tissue riboflavin and flavin enzymes in mice
P A Prasad1, A V Lakshmi, P Suresh
1National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, India.
Abstract:
The effects of Klebsiella pneumoniae infection on red blood cell and liver riboflavin levels and a few flavin enzymes were examined to verify our earlier hypothesis based on human experience that upper respiratory infections result in mobilization of riboflavin from tissues into blood, resulting in a rise in red blood cell riboflavin and an increased saturation of erythrocyte glutathione reductase (EGR) with its coenzyme flavin adenine dinucleotide (FAD; reduction in EGR activation coefficient, AC, values). Thirty-six-day-old male mice fed a diet marginally sufficient in riboflavin were injected with a single sublethal dose of K. pneumoniae. Batches of control, deficient infected and deficient uninfected animals were killed during the peak period of infection and after recovery. Infection brought about a significant rise in basal EGR activity due to greater saturation with coenzyme FAD and a concomitant reduction in EGR-AC values. On recovery, basal EGR activity decreased, and EGR-AC values increased to levels beyond control values, suggesting riboflavin deficiency. In the liver, acyl-coenzyme A dehydrogenase showed a significant decrease and pyridoxamine-phosphate oxidase activity a significant increase. Both the enzymes normalized after recovery. D-amino acid oxidase activity did not change.
Insights
Klebsiella pneumoniae infection mobilizes riboflavin, increasing red blood cell levels and erythrocyte glutathione reductase (EGR) saturation. Recovery from infection reveals riboflavin deficiency, impacting liver enzyme activity.
Area of Science:
- Biochemistry
- Microbiology
- Nutritional Science
Background:
- Infections can alter vitamin metabolism.
- Riboflavin (vitamin B2) is crucial for cellular energy and enzyme function.
- Erythrocyte glutathione reductase (EGR) activation coefficient (AC) reflects riboflavin status.
Purpose of the Study:
- To investigate the impact of Klebsiella pneumoniae infection on riboflavin status in mice.
- To test the hypothesis that infections mobilize riboflavin from tissues to blood.
- To examine changes in red blood cell and liver flavin enzyme activities during infection and recovery.
Main Methods:
- Mice on a marginal riboflavin diet were infected with Klebsiella pneumoniae.
- Control, infected, and recovered groups were analyzed.
- Activities of EGR, acyl-coenzyme A dehydrogenase, pyridoxamine-phosphate oxidase, and D-amino acid oxidase were measured.
Main Results:
- Infection increased basal EGR activity and FAD saturation, reducing EGR-AC.
- Liver acyl-coenzyme A dehydrogenase decreased, while pyridoxamine-phosphate oxidase increased during infection.
- Post-infection recovery showed decreased EGR activity and elevated EGR-AC, indicating deficiency.
Conclusions:
- Klebsiella pneumoniae infection causes riboflavin redistribution, initially increasing red blood cell FAD saturation.
- The infection and subsequent recovery process can lead to a state of functional riboflavin deficiency.
- Flavin enzyme activity in the liver is significantly affected by K. pneumoniae infection.