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Polymorphonuclear leukocyte-mediated cell and tissue injury: oxygen metabolites and their relations to human disease
Abstract:
Reactive oxygen metabolic products derived from an activated NADPH oxidase present in the cell membrane of PMNs and mononuclear phagocytic cells play a critical role in the host's defense against bacterial infection. Recent studies have also demonstrated the ability of these toxic products to initiate eukaryotic cell injury and promote the development of the acute inflammatory responses. Experimental studies suggest that neutrophil-derived oxygen metabolites contribute to the development of the tissue injury associated with a variety of disease states, including emphysema, myocardial infarction, adult respiratory distress syndrome, immune complex-mediated vasculitis, and rheumatoid arthritis. Future studies to define further the mechanisms by which reactive oxygen-derived metabolic products mediate tissue injury will provide insight into the development of new therapeutic strategies for the modulation of disease states that are mediated by the recruitment and activation of PMNs.
Insights
Reactive oxygen metabolites from activated neutrophils and phagocytes defend against bacteria but can also cause cell injury and inflammation. Understanding these mechanisms may lead to new therapies for inflammatory diseases.
Area of Science:
- Immunology
- Cell Biology
- Pathology
Background:
- Reactive oxygen metabolites (ROMs) are produced by activated neutrophils (PMNs) and mononuclear phagocytic cells.
- These products are crucial for host defense against bacterial infections.
- Recent evidence links ROMs to eukaryotic cell injury and acute inflammatory responses.
Purpose of the Study:
- To summarize the role of reactive oxygen metabolic products in host defense and disease.
- To highlight the contribution of neutrophil-derived oxygen metabolites to tissue injury.
- To emphasize the need for further research into ROM-mediated mechanisms for therapeutic development.
Main Methods:
- Review of experimental studies on reactive oxygen metabolites.
- Analysis of the role of NADPH oxidase in producing toxic oxygen products.
- Examination of the association between ROMs and various disease states.
Main Results:
- Activated NADPH oxidase in PMNs and mononuclear phagocytes generates critical reactive oxygen metabolic products.
- These toxic products contribute to host defense but also initiate cell injury.
- Neutrophil-derived oxygen metabolites are implicated in tissue damage in conditions like emphysema, myocardial infarction, ARDS, vasculitis, and rheumatoid arthritis.
Conclusions:
- Reactive oxygen metabolic products play a dual role in host defense and disease pathogenesis.
- Further elucidation of ROM-mediated tissue injury mechanisms is essential.
- This knowledge can inform the development of novel therapeutic strategies targeting PMN activation and related inflammatory diseases.