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Effects of endotoxin (lipopolysaccharides) on experimental aspergillosis in leukemic mice
1Department of Pathology, Shinshu University School of Medicine, Matsumoto, Japan.
Abstract:
In an attempt to evaluate effects of bacterial endotoxin on systemic fungal infection, experimental systemic Aspergillus infection was induced in leukemic mice (AKR strain) with (Group B) or without (Group A) preceding intraperitoneal administration of Pseudomonas aeruginosa derived lipopolysaccharides. All mice in group A died within 4 days after intravenous inoculation of Aspergillus fumigatus spores and developed extensive and disseminated fungal lesions without inflammatory reactions. In contrast, 5 of 10 mice in group B were alive at day 4 and 1 mouse in group B was alive when the experiment was terminated on the 14th day. These mice showed less extensive fungal lesions with definite, albeit minimal, inflammatory reactions which were composed of macrophages and neutrophils. In addition, serum iron levels and iron saturation rates were significantly lower in mice in group B than in group A. These results indicate that P. aeruginosa endotoxin has a deterring effect on systemic Aspergillus infection in leukemic mice.
Insights
Pseudomonas aeruginosa endotoxin administration reduced mortality in leukemic mice with systemic Aspergillus infection. This endotoxin pre-treatment also led to less fungal dissemination and lower iron levels in surviving mice.
Area of Science:
- Mycology
- Immunology
- Microbiology
Background:
- Systemic fungal infections pose a significant threat, particularly in immunocompromised individuals.
- Bacterial endotoxins are known to modulate host immune responses.
Purpose of the Study:
- To investigate the effect of Pseudomonas aeruginosa endotoxin on experimental systemic Aspergillus infection in leukemic mice.
Main Methods:
- Leukemic mice (AKR strain) were induced with systemic Aspergillus infection.
- Group A mice received no endotoxin, while Group B mice received preceding intraperitoneal administration of Pseudomonas aeruginosa lipopolysaccharides.
- Survival rates, fungal lesion extent, inflammatory responses, and serum iron levels were assessed.
Main Results:
- Mice without endotoxin (Group A) exhibited high mortality within 4 days with extensive fungal lesions and no inflammation.
- Mice pre-treated with endotoxin (Group B) showed increased survival (5/10 at day 4, 1/10 at day 14), reduced lesion dissemination, and minimal inflammatory reactions.
- Group B mice also displayed significantly lower serum iron levels and iron saturation rates compared to Group A.
Conclusions:
- Pseudomonas aeruginosa endotoxin demonstrates a protective effect against systemic Aspergillus infection in leukemic mice.
- The observed protection may be linked to altered inflammatory responses and reduced iron availability for fungal growth.