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Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient

BACKGROUND: During a lipopolysaccharide-induced lung inflammation, a massive accumulation of neutrophils occurs, which is normally cleared by macrophage phagocytosis following neutrophil apoptosis. However, in cases of extensive apoptosis the normal clearance system may fail, resulting in extensive...

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Autores principales: Rydell-Törmänen, Kristina, Uller, Lena, Erjefält, Jonas S
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2006
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1716176/
https://www.ncbi.nlm.nih.gov/pubmed/17166290
http://dx.doi.org/10.1186/1465-9921-7-143
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author Rydell-Törmänen, Kristina
Uller, Lena
Erjefält, Jonas S
author_facet Rydell-Törmänen, Kristina
Uller, Lena
Erjefält, Jonas S
author_sort Rydell-Törmänen, Kristina
collection PubMed
description BACKGROUND: During a lipopolysaccharide-induced lung inflammation, a massive accumulation of neutrophils occurs, which is normally cleared by macrophage phagocytosis following neutrophil apoptosis. However, in cases of extensive apoptosis the normal clearance system may fail, resulting in extensive neutrophil secondary necrosis. The aim of this study was to explore the hypothesis that neutrophils, in areas of the lung with extensive cellular infiltration, contribute to clearance by phagocytosing apoptotic cells and/or cell debris derived from secondary necrosis. METHODS: Intranasal lipopolysaccharide administration was used to induce lung inflammation in mice. The animals were sacrificed at seven time points following administration, bronchoalveolar lavage was performed and tissue samples obtained. Electron microscopy and histochemistry was used to assess neutrophil phagocytosis. RESULTS: Electron microscopic studies revealed that phagocytosing neutrophils was common, at 24 h after LPS administration almost 50% of the total number of neutrophils contained phagosomes, and the engulfed material was mainly derived from other neutrophils. Histochemistry on bronchoalvolar lavage cells further showed phagocytosing neutrophils to be frequently occurring. CONCLUSION: Neutrophils are previously known to phagocytose invading pathogens and harmful particles. However, this study demonstrates that neutrophils are also able to engulf apoptotic neutrophils or cell debris resulting from secondary necrosis of neutrophils. Neutrophils may thereby contribute to clearance and resolution of inflammation, thus acting as a back up system in situations when the macrophage clearance system is insufficient and/or overwhelmed.
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spelling pubmed-17161762006-12-22 Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient Rydell-Törmänen, Kristina Uller, Lena Erjefält, Jonas S Respir Res Research BACKGROUND: During a lipopolysaccharide-induced lung inflammation, a massive accumulation of neutrophils occurs, which is normally cleared by macrophage phagocytosis following neutrophil apoptosis. However, in cases of extensive apoptosis the normal clearance system may fail, resulting in extensive neutrophil secondary necrosis. The aim of this study was to explore the hypothesis that neutrophils, in areas of the lung with extensive cellular infiltration, contribute to clearance by phagocytosing apoptotic cells and/or cell debris derived from secondary necrosis. METHODS: Intranasal lipopolysaccharide administration was used to induce lung inflammation in mice. The animals were sacrificed at seven time points following administration, bronchoalveolar lavage was performed and tissue samples obtained. Electron microscopy and histochemistry was used to assess neutrophil phagocytosis. RESULTS: Electron microscopic studies revealed that phagocytosing neutrophils was common, at 24 h after LPS administration almost 50% of the total number of neutrophils contained phagosomes, and the engulfed material was mainly derived from other neutrophils. Histochemistry on bronchoalvolar lavage cells further showed phagocytosing neutrophils to be frequently occurring. CONCLUSION: Neutrophils are previously known to phagocytose invading pathogens and harmful particles. However, this study demonstrates that neutrophils are also able to engulf apoptotic neutrophils or cell debris resulting from secondary necrosis of neutrophils. Neutrophils may thereby contribute to clearance and resolution of inflammation, thus acting as a back up system in situations when the macrophage clearance system is insufficient and/or overwhelmed. BioMed Central 2006 2006-12-14 /pmc/articles/PMC1716176/ /pubmed/17166290 http://dx.doi.org/10.1186/1465-9921-7-143 Text en Copyright © 2006 Rydell-Törmänen et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research
Rydell-Törmänen, Kristina
Uller, Lena
Erjefält, Jonas S
Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient
title Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient
title_full Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient
title_fullStr Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient
title_full_unstemmed Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient
title_short Neutrophil cannibalism – a back up when the macrophage clearance system is insufficient
title_sort neutrophil cannibalism – a back up when the macrophage clearance system is insufficient
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1716176/
https://www.ncbi.nlm.nih.gov/pubmed/17166290
http://dx.doi.org/10.1186/1465-9921-7-143
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