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Activation of blood clotting factors by microbial proteinases
H Kaminishi1, H Hamatake, T Cho
1Department of Oral Microbiology, Fukuoka Dental College, Japan.
Abstract:
There are very few reports on the involvement of bacterial proteinases on the blood clotting system using both human plasma and purified clotting factors. We studied whether microbial proteinases from the opportunistic pathogens Candida albicans, Pseudomonas aeruginosa and Serratia marcescens activate the blood clotting cascade by using normal human plasma, human plasmas deficient in clotting factor XII or X, and also by using purified clotting factors XII, X and prothrombin. All proteinases tested activated either clotting factor XII or prothrombin in vitro, thus resulting in generation of thrombin. Clotting factor X was converted to the active form (Xa) by both Candida and Pseudomonas proteinases, but not by Serratia proteinase. These results suggest that peripheral and systemic blood circulation may be impaired by activation of the blood clotting cascade by microbial infections, especially in septic patients, which would enhance disseminated intravascular coagulation and multi-organ failure.
Insights
Microbial proteinases from opportunistic pathogens activate the blood clotting cascade, potentially impairing circulation. This research investigates how these enzymes affect clotting factors, impacting conditions like sepsis.
Area of Science:
- Microbiology
- Hematology
- Biochemistry
Background:
- Limited research exists on bacterial proteinases' role in blood clotting.
- Opportunistic pathogens like Candida albicans, Pseudomonas aeruginosa, and Serratia marcescens can cause severe infections.
Purpose of the Study:
- To investigate the activation of the human blood clotting cascade by microbial proteinases.
- To determine the specific clotting factors targeted by proteinases from C. albicans, P. aeruginosa, and S. marcescens.
Main Methods:
- Utilized normal human plasma and plasmas deficient in clotting factors XII or X.
- Employed purified clotting factors XII, X, and prothrombin for in vitro assays.
- Assessed the enzymatic activity of microbial proteinases on clotting factors.
Main Results:
- All tested microbial proteinases activated clotting factor XII or prothrombin, leading to thrombin generation.
- Candida and Pseudomonas proteinases activated clotting factor X to Xa; Serratia proteinase did not.
- Demonstrated in vitro activation of key clotting factors by microbial enzymes.
Conclusions:
- Microbial proteinases can initiate the blood clotting cascade.
- This activation may contribute to impaired blood circulation during infections, particularly in sepsis.
- Findings suggest a mechanism linking microbial infections to disseminated intravascular coagulation and multi-organ failure.