Disseminated intravascular coagulation (DIC) is an acquired clinicobiological syndrome characterized by widespread activation of coagulation leading to fibrin deposition in the vasculature, organ dysfunction, consumption of clotting factors and platelets, and life-threatening hemorrhage. Disseminated intravascular coagulation is provoked by several underlying disorders (sepsis, cancer, trauma, and pregnancy complicated with eclampsia or other calamities). Treatment of the underlying disease and elimination of the trigger mechanism are the cornerstone therapeutic approaches. Therapeutic strategies specific for DIC aim to control activation of blood coagulation and bleeding risk. The clinical trials using DIC as entry criterion are limited. Large randomized, phase III clinical trials have investigated the efficacy of antithrombin (AT), activated protein C (APC), tissue factor pathway inhibitor (TFPI), and thrombomodulin (TM) in patients with sepsis, but the diagnosis of DIC was not part of the inclusion criteria. Treatment with APC reduced 28-day mortality of patients with severe sepsis, including patients retrospectively assigned to a subgroup with sepsis-associated DIC. Treatment with APC did not have any positive effects in other patient groups. The APC treatment increased the bleeding risk in patients with sepsis, which led to the withdrawal of this drug from the market. Treatment with AT failed to reduce 28-day mortality in patients with severe sepsis, but a retrospective subgroup analysis suggested possible efficacy in patients with DIC. Clinical studies with recombinant TFPI or TM have been carried out showing promising results. The efficacy and safety of other anticoagulants (ie, unfractionated heparin, low-molecular-weight heparin) or transfusion of platelet concentrates or clotting factor concentrates have not been objectively assessed.

The circulating metabolome provides a snapshot of the physiological state of the organism responding to pathogenic challenges. Here we report alterations in the plasma metabolome reflecting the clinical presentation of COVID-19 patients with mild (ambulatory) diseases, moderate disease (radiologically confirmed pneumonitis, hospitalization and oxygen therapy), and critical disease (in intensive care). This analysis revealed major disease- and stage-associated shifts in the metabolome, meaning that at least 77 metabolites including amino acids, lipids, polyamines and sugars, as well as their derivatives, were altered in critical COVID-19 patient’s plasma as compared to mild COVID-19 patients. Among a uniformly moderate cohort of patients who received tocilizumab, only 10 metabolites were different among individuals with a favorable evolution as compared to those who required transfer into the intensive care unit. The elevation of one single metabolite, anthranilic acid, had a poor prognostic value, correlating with the maintenance of high interleukin-10 and -18 levels. Given that products of the kynurenine pathway including anthranilic acid have immunosuppressive properties, we speculate on the therapeutic utility to inhibit the rate-limiting enzymes of this pathway including indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase.

Over the last decades, antiplatelet agents, mainly aspirin and P2Y₁₂ receptor antagonists, have significantly reduced morbidity and mortality associated with arterial thrombosis. Their pharmacological characteristics, including pharmacokinetic/pharmacodynamics profiles, have been extensively studied, and a significant number of clinical trials assessing their efficacy and safety in various clinical settings have established antithrombotic efficacy. Notwithstanding, antiplatelet agents carry an inherent risk of bleeding. Given that bleeding is associated with adverse cardiovascular outcomes and mortality, there is an unmet clinical need to develop novel antiplatelet therapies that inhibit thrombosis while maintaining hemostasis. In this review, we present the currently available antiplatelet agents, with a particular focus on their targets, pharmacological characteristics, and patterns of use. We will further discuss the novel antiplatelet therapies in the pipeline, with the goal of improved clinical outcomes among patients with atherothrombotic diseases.

Rivaroxaban and apixaban are selective direct inhibitors of free and prothrombinase-bound factor Xa (FXa). Surprisingly prothrombin time (PT) is little sensitive to clinically relevant changes in drug concentration, especially with apixaban. To investigate this pharmacodynamic discrepancy we have compared the kinetics of FXa inhibition in strictly identical conditions (pH 7.48, 37 °C, 0.15 M). K_I values of 0.74 ± 0.03 and 0.47 ± 0.02 nM and k_on values of 7.3 ± 1.6 10⁶ and 2.9 ± 0.6 10⁷ M^-1 s^-1 were obtained for apixaban and rivaroxaban, respectively. To investigate if these constants rationalise the inhibitor pharmacodynamics, we used numerical integration to evaluate impact of FXa inhibition on thrombin generation assay (TGA) and PT. Simulation predicted that in TGA triggered with 20 pM tissue factor, 100 ng/ml apixaban or rivaroxaban increased 1.8– or 3.0-fold the lag time and 1.4– or 2.0-fold the time to peak, whilst decreasing 1.2– or 3.1-fold the maximum thrombin and 1.7– or 3.5-fold the endogenous thrombin potential. These numbers were consistent with those obtained through the corresponding TGA triggered in plasma spiked with apixaban or rivaroxaban. Simulated PT ratios were also consistent with the corresponding plasma PT: markedly less sensitive to apixaban than to rivaroxaban. Analogous differences in TGA and PT were obtained irrespective of the drug amount added. We concluded that kon values for FXa of apixaban and rivaroxaban rationalise the unexpected lower sensitivity of PT and TGA to the former.