Related Experiment Videos
Inhibition of ristocetin-induced platelet agglutination by vancomycin
Abstract:
Ristocetin and vancomycin are structurally similar glycopeptide antibiotics. Both vancomycin and ristocetin in high concentrations (3.0 mg/ml) cause the precipitation of fibrinogen, plasminogen, and IgG from platelet-poor plasma (PPP). In contrast to ristocetin, vanomycin (0.5-1.5 mg/ml) does not agglutinate platelets in normal platelet-rich plasma (PRP) or formalin-treated platelets in the presence of normal PPP. Preincubation of vancomycin (0.5-1.25 mg/ml) with normal PRP, von Willebrand platelets in normal PPP, or formalinized platelets results in inhibition of platelet agglutination induced by ristocetin (0.7-1.25 mg/ml) or ristocetin and normal PPP. This inhibition can be overcome by increasing the final concentration of ristocetin in the platelet suspension. Preincubation of formalin-treated platelets with the major fraction obtained by carboxymethyl-Sephadex C-50 chromatography of commercial vancomycin also results in inhibition of agglutination induced by ristocetin and normal PPP. Incubation with vancomycin (1.25 mg/ml) does not interfere with von Willebrand factor (vWF) or factor VIII coagulant activities in normal PPP or in Sepharose 4B void volume fractions of PPP. These results indicate that vancomycin interacts with normal, von Willebrand, and formalin-treated platelets and inhibits the binding of ristocetin (or ristocetin-vWF complexes).
Insights
Vancomycin, a glycopeptide antibiotic, inhibits ristocetin-induced platelet agglutination by interacting with platelets. This interaction prevents the binding of ristocetin and von Willebrand factor complexes.
Area of Science:
- Biochemistry
- Hematology
- Pharmacology
Background:
- Ristocetin and vancomycin are structurally similar glycopeptide antibiotics.
- High concentrations of both can precipitate plasma proteins like fibrinogen, plasminogen, and IgG.
- Vancomycin differs from ristocetin in its inability to directly agglutinate platelets.
Purpose of the Study:
- To investigate the interaction between vancomycin and platelets.
- To determine if vancomycin affects ristocetin-induced platelet agglutination.
- To elucidate the mechanism by which vancomycin might interfere with platelet function.
Main Methods:
- Platelet aggregation assays using platelet-rich plasma (PRP) and formalin-treated platelets.
- Testing vancomycin's effect on ristocetin-induced agglutination.
- Assessing vancomycin's impact on von Willebrand factor (vWF) and factor VIII activity.
Main Results:
- Vancomycin (0.5-1.5 mg/ml) does not agglutinate platelets.
- Preincubation with vancomycin inhibits ristocetin-induced platelet agglutination.
- This inhibition is overcome by increased ristocetin concentration.
- Vancomycin does not affect vWF or factor VIII coagulant activities.
Conclusions:
- Vancomycin interacts with normal, von Willebrand, and formalin-treated platelets.
- Vancomycin inhibits the binding of ristocetin and ristocetin-vWF complexes to platelets.
- This suggests a novel mechanism of interaction between vancomycin and platelet function.