Bacterial proteases and haemostasis dysregulation in the CF lung.

Abstract

BACKGROUND: Pathogenic bacteria which chronically colonise the cystic fibrosis (CF) lung produce a number of virulence determinants, including distinct proteolytic activities. The potential role bacterial proteases play on haemostatic dysregulation within the CF lung is, however, poorly defined, despite haemoptysis being a common complication in CF. METHODS: The potential impact of known CF pathogens (Pseudomonas aeruginosa and Burkholderia cepacia complex spp.) on haemostasis was examined for their ability to degrade fibrinogen and dysregulate fibrin clot formation and platelet aggregation. RESULTS: Results demonstrate that key CF pathogens growing as a biofilm on mucin exhibit considerable fibrinogenolytic activity, resulting in fibrinogen breakdown, impaired clot formation, and modulation of platelet aggregation. Human neutrophil elastase may also contribute to fibrinogen breakdown and dysregulated clot formation at high concentration. CONCLUSION: Bacterial-derived proteases may play an important role in the dysregulation of airway haemostasis, and potentially contribute to episodes of haemoptysis within the CF lung.Funding was provided by a grant to LM, AMcD and JSE from the CF Trust, UK (Big Lottery Funding/UK CF Microbiology Consortium) which supported GE (PhD studentship). MM was funded by a Department of Education and Learning (DEL), Northern Ireland PhD studentship