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Effects of leptospiral lipopolysaccharide on rabbit platelets
E Isogai1, H Kitagawa, H Isogai
1Dept. of Preventive Dentistry, School of Dentistry, Higashi Nippon Gakuen Univ., Hokkaido, Japan.
Abstract:
Leptospiral lipopolysaccharides (LPSs) extracted from Leptospira interrogans serovar copenhageni virulent strain Shibaura, serovar canicola virulent strain Moulton, and serovar hebdomadis strain Hebdomadis, were tested for their ability to induce platelet aggregation and/or lysis in rabbit platelet-rich plasma (PRP). All showed positive reactions with a release of adenosine triphosphate (ATP) and serotonin. The values, however, were different from each other. The ability of leptospiral LPS extracted from serovar copenhageni virulent strain Shibaura (I-LPS) to induce platelet aggregation was the highest of all. After treatment of I-LPS, the platelets developed a ruffled surface with appearance of pseudopodia as observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). I-LPS also showed cytotoxicity for the platelets. Degenerative or lytic changes were recognized in 44.5% of the platelets which were observed 60 min after I-LPS treatment.
Insights
Leptospiral lipopolysaccharides (LPSs) from three Leptospira serovars induced platelet aggregation and lysis. The LPS from serovar copenhageni showed the highest platelet aggregation and cytotoxicity.
Area of Science:
- Microbiology
- Immunology
- Hematology
Background:
- Leptospiral lipopolysaccharides (LPSs) are key virulence factors in Leptospira infections.
- Platelets play a crucial role in hemostasis and immune responses.
- The interaction between bacterial LPS and platelets is not fully understood.
Purpose of the Study:
- To investigate the effects of Leptospira interrogans LPS on rabbit platelets.
- To compare the platelet-aggregating and cytotoxic potential of LPS from different Leptospira serovars.
Main Methods:
- Leptospiral LPS extracted from three virulent strains (serovar copenhageni, canicola, and hebdomadis).
- Platelet-rich plasma (PRP) from rabbits used for aggregation and lysis assays.
- Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) for ultrastructural analysis.
- Measurement of adenosine triphosphate (ATP) and serotonin release.
Main Results:
- All tested LPSs induced platelet aggregation and released ATP and serotonin.
- LPS from Leptospira interrogans serovar copenhageni (I-LPS) exhibited the highest platelet aggregation.
- TEM and SEM revealed platelet surface changes, including pseudopodia formation, upon I-LPS treatment.
- I-LPS demonstrated significant cytotoxicity, causing degenerative or lytic changes in 44.5% of platelets within 60 minutes.
Conclusions:
- Leptospiral LPS can activate and damage platelets.
- Serovar copenhageni LPS is particularly potent in inducing platelet aggregation and cytotoxicity.
- These findings suggest a role for platelet activation and damage in leptospirosis pathogenesis.