PB1097 - Salvianolic Acid B Inhibits Thrombosis and Directly Blocks the Thrombin Catalytic Site

Tuesday, June 25, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Co-Author(s)

YW

Yiming Wang

Assistant Professor
The Hospital for Sick Children
Toronto, Ontario, Canada
MN

Miguel Neves

Post-doc fellow
St. Michael's Hospital
Toronto, Ontario, Canada
TN

Tiffany Ni

Graduate Student
St. Michael's Hospital
Toronto, Ontario, Canada
DM

Daniel Mackeigan

Graduate Student
St. Michael's Hospital
Toronto, Ontario, Canada
AS

Aron Shoara

Post-doc fellow
St. Michael's Hospital
Toronto, Ontario, Canada
XL

Xi Lei

Research staff
St. Michael's Hospital
Toronto, Ontario, Canada
SS

Sladjana Slavkovic

Post-doc fellow
St. Michael's Hospital
Torotno, Ontario, Canada
SY

Si-Yang Yu

Post-doc fellow
St. Michael's Hospital
Toronto, Ontario, Canada
TS

Tyler Stratton

Graduate Student
St. Michael's Hospital
Toronto, Ontario, Canada
RG

Reid Gallant

Graduate Student
St. Michael's Hospital
Toronto, Ontario, Canada
DZ

Dan Zhang

Post-doc fellow
St. Michael's Hospital
Toronto, Ontario, Canada
XX

Xiaohong Xu

Graduate Student
St. Michael's Hospital
Toronto, Ontario, Canada
CF

Cheryl Fernandes

Undergraduate student
St. Michael's Hospital
Toronto, Ontario, Canada
GZ

Guangheng Zhu

Research staff
St. Michael's Hospital
Toronto, Ontario, Canada
LD

Logan Donaldson

Professor
York University
Toronto, Ontario, Canada
PJ

Philip Johnson

Professor
York University
Toronto, Ontario, Canada
KC

Kim Connelly

Professor
St. Michael's Hospital
Toronto, Ontario, Canada
MR

Margaret Rand

Professor
The Hospital for Sick Children
Toronto, Ontario, Canada

Presenting Author(s)

Heyu Ni, MD, PhD

Professor
University of Toronto / Canadian Blood Services
Toronto, Ontario, Canada

Background: Salvianolic acid B (SAB) is a major component of Salvia miltiorrhiza root (Danshen), widely used in East/Southeast Asia for centuries to treat cardiovascular diseases. Danshen depside salt, 85% of which is made up of SAB, is approved in China to treat chronic angina. Although clinical observations suggest that Danshen extracts inhibited arterial and venous thrombosis, the exact mechanism has not been adequately elucidated.

Aims: To delineate the anti-thrombotic mechanisms of SAB.

Methods: We applied platelet aggregation and coagulation assays, perfusion chambers, and intravital microscopy models. The inhibition kinetics and binding affinity of SAB to thrombin are measured by thrombin enzymatic assays, intrinsic fluorescence spectrophotometry, and isothermal titration calorimetry (ITC). We used molecular in silico docking models to predict the interactions of SAB with thrombin.

Results: SAB dose-dependently inhibited platelet activation and aggregation induced by thrombin. SAB also reduced platelet aggregation induced by ADP and collagen. SAB attenuated blood coagulation by modifying fibrin network structures and significantly decreased thrombus formation in mouse laser-injury cremaster arteriole and FeCl3-induced carotid artery thrombosis models, as well as the human blood perfusion chamber thrombosis model. The direct SAB-thrombin interaction was confirmed by enzymatic assays, intrinsic fluorescence spectrophotometry, and ITC. Interestingly, SAB shares key structural similarities to the trisubstituted benzimidazole class of thrombin inhibitors, such as dabigatran. Molecular docking models predicted the binding of SAB to the thrombin active site.

Conclusion(s): Our data established SAB as the first herb-derived direct thrombin catalytic site inhibitor, suppressing thrombosis through both thrombin-dependent and -independent pathways. Purified SAB may be a cost-effective agent for treating arterial and deep vein thrombosis.