Safety and Feasibility of Treatment with Rivaroxaban for Non-Canonical Indications: A Case Series Analysis

Innovative Three-Step Microwave-Promoted Synthesis of N-Propargyltetrahydroquinoline and 1,2,3-Triazole Derivatives as a Potential Factor Xa (FXa) Inhibitors: Drug Design, Synthesis, and Biological Evaluation

The coagulation cascade is the process of the conversion of soluble fibrinogen to insoluble fibrin that terminates in production of a clot. Factor Xa (FXa) is a serine protease involved in the blood coagulation cascade. Moreover, FXa plays a vital role in the enzymatic sequence which ends with the thrombus production. Thrombosis is a common causal pathology for three widespread cardiovascular syndromes: acute coronary syndrome (ACS), venous thromboembolism (VTE), and strokes. In this research a series of N-propargyltetrahydroquinoline and 1,2,3-triazole derivatives as a potential factor Xa (FXa) inhibitor were designed, synthesized, and evaluated for their FXa inhibitor activity, cytotoxicity activity and coagulation parameters. Rational design for the desired novel molecules was performed through protein-ligand complexes selection and ligand clustering. The microwave-assisted synthetic strategy of selected compounds was carried out by using Ullmann-Goldberg, N-propargylation, Mannich addition, Friedel-Crafts, and 1,3-dipolar cycloaddition type reactions under microwave irradiation. The microwave methodology proved to be an efficient way to obtain all novel compounds in high yields (73–93%). Furthermore, a thermochemical analysis, optimization and reactivity indexes such as electronic chemical potential (µ), chemical hardness (η), and electrophilicity (ω) were performed to understand the relationship between the structure and the energetic behavior of all the series. Then, in vitro analysis showed that compounds 27, 29–31, and 34 exhibited inhibitory activity against FXa and the corresponding half maximal inhibitory concentration (IC₅₀) values were calculated. Next, a cell viability assay in HEK293 and HepG2 cell lines, and coagulation parameters (anti FXa, Prothrombin time (PT), activated Partial Thromboplastin Time (aPTT)) of the most active novel molecules were performed to determine the corresponding cytotoxicity and possible action on clotting pathways. The obtained results suggest that compounds 27 and 29 inhibited FXa targeting through coagulation factors in the intrinsic and extrinsic pathways. However, compound 34 may target coagulation FXa mainly by the extrinsic and common pathway. Interestingly, the most active compounds in relation to the inhibition activity against FXa and coagulation parameters did not show toxicity at the performed coagulation assay concentrations. Finally, docking studies confirmed the preferential binding mode of N-propargyltetrahydroquinoline and 1,2,3-triazole derivatives inside the active site of FXa.

Incidence of Visible Hematuria Among Antithrombotic Agents: A Systematic Review of Over 175,000 Patients

OBJECTIVE

To determine the probability of visible hematuria with antithrombotic agents and to evaluate association of urologic etiology in antithrombotic-related hematuria.

METHODS

Preferred Reporting Items in Systematic Reviews and Meta-Analyses guidelines were followed to conduct a systematic review using search engines PUBMED and SCOPUS with the terms "(hematuria) OR (haematuria) OR urinary bleeding)) AND ((anticoagulants) OR anticoagulation) OR noac) OR novel anticoagulants) OR antiplatelet) OR dabigatran) OR rivaroxaban) OR apixaban) OR warfarin) OR aspirin) OR heparin) OR dipyridamole)." Raw data were used to perform a pooled analysis. Chi-square and logistic regression analysis were used for statistical analyses.

RESULTS

Twenty-two studies describing 175,114 patients met inclusion criteria. Odds ratio of hematuria with warfarin to rivoraxaban was 33 and warfarin to dabigatran was 16. The odds ratio of hematuria for oral anticoagulant (26.7%) to prophylactic parenteral anticoagulant (1.1%) agents was 9.6. Antiplatelet agents are 76 times less likely to cause hematuria compared to anticoagulants. Odds of hematuria with aspirin were 6.7 times the odds with clopidogrel and 3.5 times the odds with ticagrelor. Dabigatran was 198 times more likely to cause major hematuria compared to warfarin, whereas clopidogrel is 1.2 times more likely to cause major hematuria compared to aspirin. Urologic pathology was identified in 44% (234/532) of cases, malignancy in 24%.

CONCLUSION

Warfarin use poses the greatest risk for hematuria but is unlikely to cause major hematuria, whereas novel antithrombotic agents are more commonly associated with major hematuria. This review further characterizes the risk profile of antithrombotic agents and associated hematuria to equip clinicians with knowledge to choose an appropriate antithrombotic agent in patients with high-risk hematuria.

Novel FXa Inhibitor Identification through Integration of Ligand- and Structure-Based Approaches

Factor Xa (FXa), a vitamin K-dependent serine protease plays a pivotal role in the coagulation cascade, one of the most interesting targets for the development of new anticoagulants. In the present work, we performed a virtual screening campaign based on ligand-based shape and electrostatic similarity search and protein-ligand docking to discover novel FXa-targeted scaffolds for further development of inhibitors. From an initial set of 260,000 compounds from the NCI Open database, 30 potential FXa inhibitors were identified and selected for in vitro biological evaluation. Compound 5 (NSC635393, 4-(3-methyl-4H-1,4-benzothiazin-2-yl)-2,4-dioxo-N-phenylbutanamide) displayed an IC₅₀ value of 2.02 nM against human FXa. The identified compound may serve as starting point for the development of novel FXa inhibitors.