1. Sex-dependent balance between thrombin and plasmin generation in the presence of thrombomodulin
Ivan D Tarandovskiy, Paul W Buehler, Elena Karnaukhova J Thromb Thrombolysis. 2022 Dec 12. doi: 10.1007/s11239-022-02742-1. Online ahead of print.
Background: Assessing simultaneous generation of thrombin (TG) and plasmin (PG) is an approach to evaluate the balance between coagulation and fibrinolysis with sensitivity to predict endogenous thrombin and plasmin generation. The addition of thrombomodulin (TM), provides the essential component for thrombin activation of protein C and thrombin-activatable fibrinolysis inhibitor. However, the influence of sex on the balance between TG and PG with and without TM addition has not been investigated to date. Objectives: To investigate the possible sex-based differences in TG and PG in the presence and absence of TM. Methods: Simultaneous TG and PG were measured in plasma samples obtained from 17 males and 17 females upon tissue factor and tissue plasminogen activator addition. Thrombin- and plasmin-specific fluorogenic substrates Z-Gly-Gly-Arg-AMC and Boc-Glu-Lys-Lys-AMC were used in the study. Thrombin and plasmin peak height (TPH and PPH) and production rate (TPR and PPR) values were determined. To evaluate the balance between TG and PG, the ratios between TPH and PPH (TPH/PPH) and TPR and PPR (TPR/PPR) were calculated. Results and conclusions: TPH between males and females demonstrated significant difference regardless of TM addition. TPR demonstrated differences between males and females only upon TM addition, while PG parameters was not dependent on the sex of the donor. TM significantly lowered TPH/PPH in males, and enhanced TPR/PPR in females. Thus, TPH/PPH and TPR/PPR significantly differed between men and women. Our results indicate that TM may act differently in males and females by shifting the underlying TG/PG balance to fibrinolysis in males and to coagulation in females.
2. The behaviour of urokinase and porcine kidney cell plasminogen activator towards some synthetic peptides
B Walker, D T Elmore Thromb Res. 1984 Apr 15;34(2):103-7. doi: 10.1016/0049-3848(84)90066-5.
The behaviour of human urokinase and porcine kidney cell plasminogen activator towards some synthetic substrates has been investigated. Although N- benzyloxycarbonylglycylglycyl -L-arginine 4-methyl-7- coumarylamide (Z-Gly-Gly-Arg-Amc) (I), glutaryl-Gly-Arg-Amc (II) and Z-Gly-Gly-Arg-Val-OMe (III) were substrates, Boc-Gly-Gly-Arg-Val-Val-Gly-Gly-OEt (IV) and Z-Ala-Pro-Gly-Arg-Val-Val-Gly-Gly-OEt (V) were neither substrates nor inhibitors. Steady-state kinetic parameters for the hydrolysis of (II) and (III) by urokinase and porcine kidney cell plasminogen activator were similar.
3. Inhibition of human thrombin by the constituents of licorice: inhibition kinetics and mechanistic insights through in vitro and in silico studies
Cheng-Cheng Shi, et al. RSC Adv. 2020 Jan 22;10(7):3626-3635. doi: 10.1039/c9ra09203j.
Thrombin inhibition therapy is a practical strategy to reduce thrombotic and cardiovascular risks via blocking the formation of blood clots. This study aimed to identify naturally occurring thrombin inhibitors from licorice (one of the most popular edible herbs), as well as to investigate their inhibitory mechanisms. Among all tested licorice constituents, licochalcone A was found as the most efficacious agent against human thrombin (IC50 = 7.96 μM). Inhibition kinetic analyses demonstrated that licochalcone A was a mixed inhibitor against thrombin-mediated Z-Gly-Gly-Arg-AMC acetate hydrolysis, with a K i value of 12.23 μM. Furthermore, mass spectrometry-based chemoproteomic assays and molecular docking simulations revealed that licochalcone A could bind to human thrombin at both exosite I and the catalytic site. In summary, our findings demonstrated that the chalcones isolated from licorice were a new class of direct thrombin inhibitors, also suggesting that licochalcone A was a promising lead compound for developing novel anti-thrombotic agents.