Therapeutic effects and molecular mechanisms of natural products in thrombosis

Thrombotic disorders, such as myocardial infarction and stroke, are the leading cause of death in the global population and have become a health problem worldwide. Drug therapy is one of the main antithrombotic strategies, but antithrombotic drugs are not completely safe, especially the risk of bleeding at therapeutic doses. Recently, natural products have received widespread interest due to their significant efficacy and high safety, and an increasing number of studies have demonstrated their antithrombotic activity. In this review, articles from databases, such as Web of Science, PubMed, and China National Knowledge Infrastructure, were filtered and the relevant information was extracted according to predefined criteria. As a result, more than 100 natural products with significant antithrombotic activity were identified, including flavonoids, phenylpropanoids, quinones, terpenoids, steroids, and alkaloids. These compounds exert antithrombotic effects by inhibiting platelet activation, suppressing the coagulation cascade, and promoting fibrinolysis. In addition, several natural products also inhibit thrombosis by regulating miRNA expression, anti-inflammatory, and other pathways. This review systematically summarizes the natural products with antithrombotic activity, including their therapeutic effects, mechanisms, and clinical applications, aiming to provide a reference for the development of new antithrombotic drugs.

Active Dual-Protein Coating Assisted by Stepwise Protein-Protein Interactions Assembly Reduces Thrombosis and Infection

Universal protein coatings have recently gained wide interest in medical applications due to their biocompatibility and ease of fabrication. However, the challenge persists in protein activity preservation, significantly complicating the functional design of these coatings. Herein, an active dual-protein surface engineering strategy assisted by a facile stepwise protein-protein interactions assembly (SPPIA) method for catheters to reduce clot formation and infection is proposed. This strategy is realized first by the partial oxidation of bovine serum albumin (BSA) and lysozyme (LZM) for creating stable nucleation platforms via hydrophobic interaction, followed by the assembly of nonoxidized BSA (pI, the isoelectric point, ≈4.7) and LZM (pI ≈11) through electrostatic interaction owing to their opposite charge under neutral conditions. The SPPIA method effectively preserves the conformation and functionality of both BSA and LZM, thus endowing the resultant coating with potent antithrombotic and bactericidal properties. Furthermore, the stable nucleation platform ensures the adhesion and durability of the coating, resisting thrombosis and bacterial proliferation even after 15 days of PBS immersion. Overall, the SPPIA approach not only provides a new strategy for the fabrication of active protein coatings but also shows promise for the surface engineering technology of catheters.

Recent progress in functional modification and crosslinking of bioprosthetic heart valves

Valvular heart disease (VHD), clinically manifested as stenosis and regurgitation of native heart valve, is one of the most prevalent cardiovascular diseases with high mortality. Heart valve replacement surgery has been recognized as golden standard for the treatment of VHD. Owing to the clinical application of transcatheter heart valve replacement technic and the excellent hemodynamic performance of bioprosthetic heart valves (BHVs), implantation of BHVs has been increasing over recent years and gradually became the preferred choice for the treatment of VHD. However, BHVs might fail within 10-15 years due to structural valvular degeneration (SVD), which was greatly associated with drawbacks of glutaraldehyde crosslinked BHVs, including cytotoxicity, calcification, component degradation, mechanical failure, thrombosis and immune response. To prolong the service life of BHVs, much effort has been devoted to overcoming the drawbacks of BHVs and reducing the risk of SVD. In this review, we summarized and analyzed the research and progress on: (i) modification strategies based on glutaraldehyde crosslinked BHVs and (ii) nonglutaraldehyde crosslinking strategies for BHVs.

Clinical Profile, Treatment, and Prognosis of Left Ventricular Thrombus in Dilated Cardiomyopathy

Despite the emerging prevalence of left ventricular (LV) thrombus in dilated cardiomyopathy (DCM), clinical characteristics, management, and disease prognosis are poorly studied. We aim to assess the efficacy/safety profile of direct oral anticoagulants (DOACs) compared to warfarin by evaluating thrombus evolution, risk for stroke and systemic embolism (SSE), heart failure (HF) rehospitalization, all-cause mortality, and major adverse cardiovascular events (MACEs), and determine the impact of thrombus evolution on adverse events. We performed a historical cohort study of patients with a primary diagnosis of DCM and LV thrombus. Relationships between anticoagulants and thrombus resolution were analyzed with the Kaplan-Meier method and Cox regression. Associations between longitudinal thrombus evolution and adverse event hazard were measured with joint modeling. Among 122 patients included, 58.0% were prescribed warfarin, and 42.0% DOACs. Complete thrombus resolution at 90-day-after-index and 180-day-after-index was observed in 93 and 111 patients, with no difference in cumulative resolution between DOACs and warfarin. During a median follow-up of 12.5 months, MACE, all-cause death, SSE, and HF rehospitalization occurred in 42.6%, 27.9%, 4.1%, and 13.9% of patients, comparable in warfarin and DOACs groups. Thrombus persistence was associated with a higher risk of HF rehospitalization. Thrombus progression was associated with poor prognosis, with per unit increment in square-root-transformed thrombus-area resulting in a 1.0691-fold increase in MACE risk and a 1.0546-fold increase in death risk. This study suggests that in DCM patients with LV thrombus, DOACs were comparable to warfarin in thrombus resolution and safety profile. Thrombus persistence or progression was associated with an increased risk of HF rehospitalization, MACE, and mortality.

Effects of MaiLiuPian on carotid thrombosis in rats and acute pulmonary embolism in mice and its antithrombotic mechanism

Mailiupian (MLP) is a new patent functional food that consists of Crataegi Fructus, Notoginseng Radix, and Ginkgo Folium, which was reported to be active in improving the microcirculation based on formulation screening. However, whether it is effective in inhibiting thrombus and its mechanism has not been evaluated. Therefore, in the present study, the models of arterial thrombosis induced by FeCl₃ and the models of APE by ADP were established to evaluate the antithrombosis effect of MLP. Results showed that MLP markedly reduced the weight and size of wet thrombosis in FeCl₃ -induced rats and decreased the recovery time from symptoms of APE mice. MLP was proved to prolong APTT, PT, TT and improve the levels of t-PA and 6-keto-PGF_1α significantly, meanwhile, PAI-1 and TXB₂ were reduced apparently. By comparing tail bleeding time, MLP showed antithrombotic effects, but without the risk of bleeding, taking aspirin as a control. PRACTICAL APPLICATIONS: Our experiments proved that MLP, a new patent health food, acted on both coagulation and fibrinolytic systems and the platelet aggregation to play antithrombosis roles, providing a theoretical basis for applications of MLP in preventing or curing thrombosis diseases.

Lipid Profiles of the Heads of Four Shrimp Species by UPLC-Q-Exactive Orbitrap/MS and Their Cardiovascular Activities

Lipids are key factors in nutrition, structural function, metabolic features, and other biological functions. In this study, the lipids from the heads of four species of shrimp (Fenneropenaeus chinensis (FC), Penaeus japonicus (PJ), Penaeus vannamei (PV), and Procambarus clarkia (PCC)) were compared and characterized based on UPLC-Q-Exactive Orbitrap/MS. We compared the differences in lipid composition of four kinds of shrimp head using multivariate analysis. In addition, a zebrafish model was used to evaluate pro-angiogenic, anti-inflammatory, anti-thrombotic, and cardioprotective activities of the shrimp head lipids. The lipids from the four kinds of shrimp head had different degrees of pro-angiogenic activities, and the activities of PCC and PJ shrimp lipids were more significant than those of the other two species. Four lipid groups displayed strong anti-inflammatory activities. For antithrombotic activity, only PCC (25 μg/mL) and PV (100 μg/mL) groups showed obvious activity. In terms of cardioprotective activity, the four kinds of lipid groups significantly increased the zebrafish heart rhythms. The heart distances were shortened, except for those of the FC (100 μg/mL) and PJ (25 μg/mL) groups. Our comprehensive lipidomics analysis and bioactivity study of lipids from different sources could provide a basis for the better utilization of shrimp.

Identifying of Anti-Thrombin Active Components From Curcumae Rhizoma by Affinity-Ultrafiltration Coupled With UPLC-Q-Exactive Orbitrap/MS

Recent studies concerning products that originate from natural plants have sought to clarify active ingredients, which both explains the mechanisms of the function and aids in quality control during production. As a traditional functional plant, Curcumae Rhizoma (CR) has been proven to be effective in promoting blood circulation and removing blood stasis. However, the components that play a role in its huge compound library are still unclear. The present study aimed to develop a high-throughput screening method to identify thrombin inhibitors in CR and validate them by in vitro and in vivo experiments. The effect of CR on thrombin in HUVECs cells was determined by ELISA, then an affinity-ultrafiltration-UPLC-Q-Exactive Orbitrap/MS approach was applied. Agatroban and adenosine were used as positive and negative drugs respectively to verify the reliability of the established method. The in vitro activity of the compounds was determined by specific substrate S-2238. The in vivo effect of the active ingredients was determined using zebrafish. Molecular docking was used to understand the internal interactions between compounds and enzymes. ELISA results showed that CR had an inhibitory effect on thrombin. The screening method established in this paper is reliable, by which a total of 15 active compounds were successfully identified. This study is the first to report that C7, 8, and 11 have in vitro thrombin-inhibitory activity and significantly inhibit thrombosis in zebrafish models at a safe dose. Molecular docking studies were employed to analyze the possible active binding sites, with the results suggesting that compound 16 is likely a better thrombin inhibitor compared with the other compounds. Based on the affinity-ultrafiltration-UPLC-Q-Exactive Orbitrap/MS approach, a precisely targeted therapy method using bio-active compounds from CR might be successfully established, which also provides a valuable reference for targeted therapy, mechanism exploration, and the quality control of traditional herbal medicine.

Endothelium-Mimicking Surface Combats Thrombosis and Biofouling via Synergistic Long- and Short-Distance Defense Strategy

Thrombosis and infections are the main causes of implant failures (e.g., extracorporeal circuits and indwelling medical devices), which induce significant morbidity and mortality. In this work, an endothelium-mimicking surface is engineered, which combines the nitric oxide (NO)-generating property and anti-fouling function of a healthy endothelium. The released gas signal molecules NO and the glycocalyx matrix macromolecules hyaluronic acid (HA) jointly combine long- and short-distance defense actions against thrombogenicity and biofouling. The biomimetic surface is efficiently fabricated by cografting a NO-generating species (i.e., Tri-tert-butyl 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetate-chelated Cu²⁺ , DTris@Cu) and the macromolecular HA on an aminated tube surface through one-pot amide condensation chemistry. The active attack (i.e., NO release) and zone defense (i.e., HA tethering) system endow the tubing surface with significant inhibition of platelets, fibrinogen, and bacteria adhesion, finally leading to long-term anti-thrombogenic and anti-fouling properties over 1 month. It is envisioned that this endothelium-mimicking surface engineering strategy will provide a promising solution to address the clinical issues of long-term blood-contacting devices associated with thrombosis and infection.

Robust and Antiswelling Hollow Hydrogel Tube with Antibacterial and Antithrombotic Ability for Emergency Vascular Replacement

Infection and thrombosis are the two major complications in almost any indwelling intravascular catheters, leading to adverse consequences. Here, we report a robust and antiswelling hollow hydrogel tube that is prepared by copolymerizing a hydrogen-bonding (H-bonding) monomer and a zinc methacrylate (ZMA) monomer in the absence of any chemical cross-linker. The strong H-bonding interactions from the side chain of N-acryloylsemicarbazide (NASC) endow the hydrogel with high mechanical strength and swelling stability. Introduction of ZMA affords a superhydrophilic surface, and the release of a zinc ion (Zn²⁺) from the hydrogel can kill nearly 100% both of Staphylococcus aureus and Escherichia coli, indicating its excellent antibacterial ability. Importantly, the P(NASC-co-ZMA) hydrogel exhibits better antithrombosis ability due to the resistant adhesion of fibrinogen protein and platelets, as well binding calcium ions (Ca²⁺) from the blood. The hydrogel tube is used to connect the ex vivo arteriovenous shunt circuit or implanted into the left carotid artery in the rabbit model, showing a better patency rate. All of these results suggest that this hydrogel tube may mitigate infection and thrombosis complications, thus holding potential as an artificial blood vessel for emergency vascular replacement.

Rutin-Loaded Silver Nanoparticles With Antithrombotic Function

In this paper, we fabricated rutin-loaded silver nanoparticles (Rutin@AgNPs) as the nano-anticoagulant with antithrombotic function. The serum stability, anticoagulation activity, and bleeding risk of Rutin@AgNPs were evaluated. The results showed Rutin@AgNPs had good serum stability, hemocompatibility, and cytocompatibility. The anticoagulation activity of rutin was maintained, and its stability and aqueous solubility were improved. The Rutin@AgNPs could provide a sustained release to prolong the half-life of rutin. The results of the coagulation parameter assay and thrombus formation test in mice model showed that the activated partial thromboplastin time and prothrombin time were prolonged, and Rutin@AgNPs inhibited the thrombosis in the 48 h period. Moreover, the limited bleeding time indicated that the Rutin@AgNPs significantly minimized the hemorrhage risk of rutin. This Rutin@AgNPs is a potential anticoagulant for antithrombotic therapy.

Marine Antithrombotics

Thrombosis remains a prime reason of mortality worldwide. With the available antithrombotic drugs, bleeding remains the major downside of current treatments. This raises a clinical concern for all patients undergoing antithrombotic therapy. Novel antithrombotics from marine sources offer a promising therapeutic alternative to this pathology. However, for any potential new molecule to be introduced as a real alternative to existing drugs, the exhibition of comparable anticoagulant potential with minimal off-target effects must be achieved. The relevance of marine antithrombotics, particularly sulfated polysaccharides, is largely due to their unique mechanisms of action and lack of bleeding. There have been many investigations in the field and, in recent years, results have confirmed the role of potential marine molecules as alternative antithrombotics. Nonetheless, further clinical studies are required. This review covers the core of the data available so far regarding the science of marine molecules with potential medical applications to treat thrombosis. After a general discussion about the major biochemical steps involved in this pathology, we discuss the key structural and biomedical aspects of marine molecules of both low and high molecular weight endowed with antithrombotic/anticoagulant properties.

Lipid Fingerprinting of Different Material Sources by UPLC-Q-Exactive Orbitrap/MS Approach and Their Zebrafish-Based Activities Comparison

Lipids are considered to be critical contributors to nutrition, structural function, metabolic function, and other biological roles. They vary from one biological source to another. Here, the lipids from three common sources (soybean, egg yolk, and shrimp head) were comprehensively compared and characterized using the lipidomics approach, together with the UPLC-Q-Exactive Orbitrap/MS method. A total of 3027 lipid structures containing 778 fatty acids, 750 glycerolipids, 1283 glycerophospholipids, 200 sphingolipids, and 16 sterol lipids were first identified and quantified in these resources. The characteristic lipid species with significant differences among groups were determined by lipidomics analysis. Besides, the antithrombotic, antioxidant, and anti-inflammatory activities were evaluated based on the zebrafish model. The correlation between differential lipids and activities was also analyzed. Our comprehensive lipidomics profiling and bioactivities of lipids from different sources in vivo can provide evidence for their future applications.

Anticoagulant Decapeptide Interacts with Thrombin at the Active Site and Exosite-I

Thrombin can be used as a target for its inhibitors to prevent blood coagulation. A novel peptide (TKLTEEEKNR, PfCN) identified from αS2-casein (fragments 211-220) with high anticoagulant activity was screened and prepared. The activated partial thromboplastin time, prothrombin time, and thrombin time, at the concentration of 4 mM, prolonged about 19, 2.5 and 5.5 s, respectively. At the same concentration, the fibrinogen clotting time prolonged from 25.5 ± 0.7 to 38.3 ± 1.3 s. The thrombin inhibitory efficiency in vitro (IC₅₀ value of 29.27 mM) and antithrombosis effect in vivo were determined. The secondary structure of thrombin, which was influenced by PfCN, indicates that PfCN can bind to thrombin. Isothermal titration calorimetry and the chromogenic substrate test showed that PfCN belongs to the bivalent thrombin inhibitor like bivalirudin. Although the effect was not as good as bivalirudin, in the animal experiment, bleeding occurred in the bivalirudin group but not in the PfCN group. Moreover, molecular docking illustrates the mechanism for the antithrombin activity of PfCN. These results indicated that PfCN could be used as an effective thrombin inhibitor with broad potential for the prevention of thrombotic acute pulmonary embolism and other thrombotic events.

Antithrombotic Regimens in Patients With Percutaneous Coronary Intervention Whom an Anticoagulant Is Indicated: A Systematic Review and Network Meta-Analysis

Background: Patients undergoing percutaneous coronary intervention (PCI) who require anticoagulant therapy are at increased risk of bleeding. The optimal regimen for these patients is uncertain. This study aimed to compare safety and efficacy of antithrombotic regimens used in patients undergoing PCI with concomitant anticoagulant therapy. Methods: A systematic review and network meta-analysis was performed among studies comparing antithrombotic regimens for anticoagulated patients undergoing PCI. The primary outcome of interest was major bleeding. The secondary outcomes were coronary events. The reference intervention was classic triple therapy (aspirin plus clopidogrel plus VKA). Cluster rank incorporating risk (major bleeding) and benefit (all-cause death) was performed to identify the most appropriate regimen(s). Results: There were 3 RCTs (6 interventions) and 29 non-RCTs (8 interventions) that met the inclusion criteria with 22,179 patients. Network meta-analysis of RCTs indicated that dual therapy (DT), either with vitamin K antagonist (VKA) or direct anticoagulant (DOAC) plus an antiplatelet, significantly reduced the risk of major bleeding compared to triple therapy (TT) [pooled RR of 0.51 (0.30-0.87) and 0.68 (0.49-0.94), respectively]. In addition, VKA-DT significantly reduced the risk of all-cause death compared to TT [pooled RR of 0.40 (0.17-0.93)]. Results from network meta-analysis of non-RCT paralleled that of RCTs. No significant differences of coronary events were found. Conclusions: In conclusion, for anticoagulated patients undergoing PCI, dual therapy, either with warfarin or DOAC plus an antiplatelet, should be considered due to its optimal balance on efficacy and safety.

Immobilization of heparin on decellularized kidney scaffold to construct microenvironment for antithrombosis and inducing reendothelialization

In recent years, rapid development of tissue engineering technology provides possibilities for the construction of artificial tissues or organs. In construction of engineered kidneys, researchers used native decellularized extracellular matrix (ECM) as the scaffolds to recellularization. However, thrombosis has been a great issue that hinders the progress of transplantation in vivo. In this study, heparin was immobilized to the collagen part of decellularized scaffold with collagen-binding peptide (CBP). Through the anticoagulant and endothelial cell reperfusion experiments, it can be demonstrated that the heparinized scaffolds absorbed less platelets and red blood cells which can effectively reduce the formation of thrombosis. Moreover, it is conducive to long-term adhesion of endothelial cells which is important for the formation of subsequent vascularization. Taken together, our results reveal that the whole kidney can be modified by CBP-heparin composite to reduce the thrombosis and provide the better conditions for neovascularization.

Anticoagulant and Antithrombotic Properties of Three Structurally Correlated Sea Urchin Sulfated Glycans and Their Low-Molecular-Weight Derivatives

The anticoagulant and antithrombotic properties of three structurally correlated sea urchin-derived 3-linked sulfated α-glycans and their low molecular-weight derivatives were screened comparatively through various in vitro and in vivo methods. These methods include activated partial thromboplastin time, the inhibitory activity of antithrombin over thrombin and factor Xa, venous antithrombosis, the inhibition of platelet aggregation, the activation of factor XII, and bleeding. While the 2-sulfated fucan from Strongylocentrotus franciscanus was observed to be poorly active in most assays, the 4-sulfated fucan from Lytechinus variegatus, the 2-sulfated galactan from Echinometra lucunter and their derivatives showed multiple effects. All marine compounds showed no capacity to activate factor XII and similar low bleeding tendencies regardless of the dose concentrations used to achieve the highest antithrombotic effect observed. The 2-sulfated galactan showed the best combination of results. Our work improves the background about the structure-function relationship of the marine sulfated glycans in anticoagulation and antithrombosis. Besides confirming the negative effect of the 2-sulfated fucose and the positive effect of the 2-sulfated galactose on anticoagulation in vitro, our results also demonstrate the importance of this set of structural requirements on antithrombosis in vivo, and further support the involvement of high-molecular weight and 4-sulfated fucose in both activities.

A Short Half-Life αIIbβ₃ Antagonist ANTP266 Reduces Thrombus Formation

Integrin α_IIbβ₃ plays a pivotal role in platelet aggregation. Three α_IIbβ₃ antagonists have been approved by the Food and Drug Administration (FDA) for the treatment of cardiovascular diseases. Unfortunately, all of these three drugs can cause the side effect of severe bleeding. Therefore, developing a new α_IIbβ₃ antagonist with low bleeding was needed. In the present study, we screened compounds by using a fibrinogen/integrin α_IIbβ₃ enzyme-linked immunosorbent assay (ELISA), and a novel α_IIbβ₃ antagonist ANTP266 was attained. The antithrombotic effects of ANTP266 were estimated by using two animal models, the bleeding risk was estimated by using a mice tail cutting assay, and the plasma half-life time was tested by LC-MS/MS. The results showed that ANTP266 potently decreased thrombosis formation, while not prolonging bleeding time at its effective dosage. The bleeding of ANTP266 reduced rapidly as time went on from 5 to 60 min, but tirofiban produced high bleeding continuously. The plasma half-life of ANTP266 in rats was 10.8 min. Taken together, ANTP266 is an effective antithrombotic agent with a low bleeding risk. The shorter bleeding time benefits from its short plasma half-life. ANTP266 could be a candidate for developing the α_IIbβ₃ antagonist of rapid elimination for a patient undergoing percutaneous coronary intervention.

Possible Molecular Targets of Novel Ruthenium Complexes in Antiplatelet Therapy

In oncotherapy, ruthenium (Ru) complexes are reflected as potential alternatives for platinum compounds and have been proved as encouraging anticancer drugs with high efficacy and low side effects. Cardiovascular diseases (CVDs) are mutually considered as the number one killer globally, and thrombosis is liable for the majority of CVD-related deaths. Platelets, an anuclear and small circulating blood cell, play key roles in hemostasis by inhibiting unnecessary blood loss of vascular damage by making blood clot. Platelet activation also plays a role in cancer metastasis and progression. Nevertheless, abnormal activation of platelets results in thrombosis under pathological settings such as the rupture of atherosclerotic plaques. Thrombosis diminishes the blood supply to the heart and brain resulting in heart attacks and strokes, respectively. While currently used anti-platelet drugs such as aspirin and clopidogrel demonstrate efficacy in many patients, they exert undesirable side effects. Therefore, the development of effective therapeutic strategies for the prevention and treatment of thrombotic diseases is a demanding priority. Recently, precious metal drugs have conquered the subject of metal-based drugs, and several investigators have motivated their attention on the synthesis of various ruthenium (Ru) complexes due to their prospective therapeutic values. Similarly, our recent studies established that novel ruthenium-based compounds suppressed platelet aggregation via inhibiting several signaling cascades. Our study also described the structure antiplatelet-activity relationship (SAR) of three newly synthesized ruthenium-based compounds. This review summarizes the antiplatelet activity of newly synthesized ruthenium-based compounds with their potential molecular mechanisms.

Design and synthesis of nanoscaled IQCA-TAVV as a delivery system capable of antiplatelet activation, targeting arterial thrombus and releasing IQCA

BACKGROUND

Arterial thrombosis has been associated with a series of pathological conditions, and the discovery of arterial thrombosis inhibitor is of clinical importance.

METHODS

By analyzing the pharmacophores of anti-platelet agents, thrombus targeting peptide and anti-thrombotic nano-systems 3S-1,2,3,4-tetrahydroisoquino-line-3-carbonyl-Thr-Ala-Arg-Gly-Asp(Val)-Val (IQCA-TAVV) was designed and prepared as a nano-scaled arterial thrombosis inhibitor.

RESULTS

In vitro the nanoparticles of IQCA-TAVV were able to adhere onto the surface of activated platelets, attenuate activated platelets to extend pseudopodia and inhibit activated platelets to form aggregators. In vivo IQCA-TAVV targeted arterial thrombus, dose dependently inhibited arterial thrombosis with a 1 nmol/kg of minimal effective dose, and the activity waŝ1670 folds of that of aspirin.

CONCLUSION

IQCA-TAVV represented the design, preparation and application of nanomedicine capable of adhering on the surface of activated platelets, attenuating platelet activation, targeting arterial thrombus and inhibiting arterial thrombosis.

Norcantharidin, a clinical used chemotherapeutic agent, acts as a powerful inhibitor by interfering with fibrinogen-integrin αIIb β3 binding in human platelets

During platelet activation, fibrinogen binds to its specific platelet receptor, integrin α_IIb β₃ , thus completing the final common pathway for platelet aggregation. Norcantharidin (NCTD) is a promising anticancer agent in China from medicinal insect blister beetle. In this study, we provided the evidence to demonstrate NCTD (0.1-1.0 μM) possesses very powerful antiplatelet activity in human platelets; nevertheless, it had no effects on surface P-selectin expression and only slight inhibition on ATP-release reaction in activated platelets. Moreover, NCTD markedly hindered integrin α_IIb β₃ activation by interfering with the binding of FITC-labelled PAC-1. It also markedly reduced the number of adherent platelets and the single platelet spreading area on immobilized fibrinogen as well as clot retraction. Additionally, NCTD attenuated phosphorylation of proteins such as integrin β₃ , Src and FAK in platelets spreading on immobilized fibrinogen. These results indicate that NCTD restricts integrin α_IIb β₃ -mediated outside-in signalling in human platelets. Besides, NCTD substantially prolonged the closure time in human whole blood and increased the occlusion time of thrombotic platelet plug formation and prolonged the bleeding time in mice. In conclusion, NCTD has dual activities, it can be a chemotherapeutic agent for cancer treatment, and the other side it possesses powerful antiplatelet activity for treating thromboembolic disorders.

N-(3-hydroxymethyl-β-carboline-1-yl-ethyl- 2-yl)-l-Phe: development toward a nanoscaled antitumor drug capable of treating complicated thrombosis and inflammation

It is well documented that the surfaces of cancer cells, activated platelets and inflammatory cells are rich in P-selectin. N-(3-hydroxymethyl-β-carboline-1-yl-ethyl-2-yl)-l-Phe (HMCEF) is a P-selectin inhibitor capable of simultaneously inhibiting thrombosis and inflammation. Based on the knowledge that P-selectin is a common target for antithrombotic, anti-inflammatory and antitumor drugs, the aim of this study article was to estimate the possibility of HMCEF as a nanoscaled antitumor drug. Images of transmission electron micro scopy, scanning electron microscopy and atomic force microscopy proved that HMCEF forms nanoparticles with a diameter of <120 nm that promote delivery in blood circulation. In vitro HMCEF intercalates into calf thymus DNA, cuts off DNA pBR22 and inhibits the proliferation of cancer cells. In vivo HMCEF dose dependently (0.2, 2 and 200 nmol/kg per day) slows tumor growth in treated S180 mice, and has a minimal effective dose of 2 nmol/kg per day. At 200 nmol/kg per day, HMCEF does not affect the liver and the kidney of the treated S180 mice, and at 20,000 nmol/kg HMCEF does not affect the liver and the kidney of the treated healthy ICR mice. HMCEF is a promising antitumor drug, which is characterized by its high safety and efficacy in the prevention of the complications of thrombosis and inflammation in patients.

Multi-Targeted Antithrombotic Therapy for Total Artificial Heart Device Patients

To prevent thrombotic or bleeding events in patients receiving a total artificial heart (TAH), agents have been used to avoid adverse events. The purpose of this article is to outline the adoption and results of a multi-targeted antithrombotic clinical procedure guideline (CPG) for TAH patients. Based on literature review of TAH anticoagulation and multiple case series, a CPG was designed to prescribe the use of multiple pharmacological agents. Total blood loss, Thromboelastograph(®) (TEG), and platelet light-transmission aggregometry (LTA) measurements were conducted on 13 TAH patients during the first 2 weeks of support in our institution. Target values and actual medians for postimplant days 1, 3, 7, and 14 were calculated for kaolinheparinase TEG, kaolin TEG, LTA, and estimated blood loss. Protocol guidelines were followed and anticoagulation management reduced bleeding and prevented thrombus formation as well as thromboembolic events in TAH patients postimplantation. The patients in this study were susceptible to a variety of possible complications such as mechanical device issues, thrombotic events, infection, and bleeding. Among them all it was clear that patients were at most risk for bleeding, particularly on postoperative days 1 through 3. However, bleeding was reduced into postoperative days 3 and 7, indicating that acceptable hemostasis was achieved with the anticoagulation protocol. The multidisciplinary, multi-targeted anticoagulation clinical procedure guideline was successful to maintain adequate antithrombotic therapy for TAH patients.

Timing of the resumption of antithrombotic agents following surgical evacuation of chronic subdural hematomas: a retrospective cohort study

OBJECTIVE

Antithrombosis (AT), defined here as either antiplatelets or anticoagulants, is a significant risk factor for the development of chronic subdural hematomas (cSDHs). Resuming AT following the evacuation of cSDH is a highly variable practice, with scant evidence in the literature for guidance. Here, a retrospective analysis of a cohort of patients from a single institution undergoing surgical drainage of cSDH was performed to evaluate postoperative complications and determine the optimal timing of the resumption of common antithrombotic agents.

METHODS

This retrospective analysis was performed on 479 patients undergoing surgical evacuation of cSDH at St. Michael's Hospital over a 5-year period (2007-2012). The collected variables included the type of AT agent, indications for AT, timing and type of postoperative complications, and the restart intervals for the AT agents, when available. Postoperative complications were classified as major hemorrhages, minor hemorrhages, or thromboembolic events.

RESULTS

Among all 479 study patients, 71 experienced major hemorrhage (14.8%), 110 experienced minor hemorrhage (23.0%), and 8 experienced thromboembolism (1.67%) postoperatively. Patients on any type of preoperative AT regimen were at a higher risk of major hemorrhage (19.0% vs 10.9%; OR 1.93; 95% CI 1.15-2.71; p = 0.014). The type of AT agent did not affect the frequency of any postoperative complications. Patients on any preoperative AT regimen experienced earlier postoperative major hemorrhages (mean 16.2 vs 26.5 days; p = 0.052) and thromboembolic events (mean 2.7 vs 51.5 days; p = 0.036) than those patients without a history of AT; the type of AT agent did not affect timing of complications. Patients who were restarted on any AT therapy postoperatively were at decreased risk of major rebleeding following resumption than those patients who were not restarted (OR 0.06; 95% CI 0.02-0.2; p < 0.01).

CONCLUSIONS

Patients with a history of preoperative AT experienced thromboembolic complications significantly earlier than those patients without AT, which peaked at 3 days postoperatively with no increase in hemorrhage risk when AT was restarted. Cursory evidence is presented that shows resuming AT early following the surgical evacuation of cSDH at 3 days postoperatively may be safe. However, much larger prospective studies are required prior to providing any definitive recommendations regarding the optimal timing and method of resumption of individual agents.

An updated review of sepsis for the anesthesiologist

Severe sepsis and septic shock continue to be among of the leading causes of death in intensive care unit patients, carrying an estimated mortality rate between 30% and 50%. This article provides an evidence-based focused review of sepsis, including an update on management strategies based on the most recent guidelines published by the Surviving Sepsis Campaign.

Recombinant thrombomodulin of different domains for pharmaceutical, biomedical, and cell transplantation applications

Thrombomodulin (TM) is a membrane glycoprotein mainly expressed by vascular endothelial cells and is involved in many physiological and pathological processes, such as coagulation, inflammation, cancer development, and embryogenesis. Human TM consists of 557 amino acids divided into five distinct domains: N-terminal lectin-like domain (designated as TMD1); six epidermal growth factor (EGF)-like domain (TMD2); Ser/Thr-rich domain (TMD3); transmembrane domain (TMD4); and cytoplasmic tail domain (TMD5). The different domains are responsible for different biological functions of TM. In the past decades, various domains of TM have been cloned and expressed for TM structural and functional study. Further, recombinant TMs of different domains show promising antithrombotic and anti-inflammatory activity in both rodents and primates and a recombinant soluble TM has been approved for therapeutic application. This review highlights recombinant TMs of diverse structures and their biological functions, as well as the complex interactions of TM with factors involved in the related biological processes. Particularly, recent advances in exploring recombinant TM of different domains for pharmaceutical, biomedical, and cell transplantation applications are summarized.

Antiplatelet and antithrombotic effect of Phyllostachys pubescens leaves and Mume Fructus combination

Background

Agents currently used for the treatment and prevention of thrombosis have a number of side effects. We conducted this study to develop antithrombotic agents from herbs that are used in food.

Methods

The 80% (v/v) ethanol extracts of Phyllostachys pubescens leaf (PL) and Mume Fructus (MF) and their combinations—2:1 (PM21), 1:1 (PM11), and 1:2 (PM12)—were evaluated on rat platelet aggregation induced by adenosine diphosphate (ADP) in vitro and on arteriovenous shunt thrombosis after 3 days of oral treatment in rats in vivo.

Results

At 100 μg/mL, PM21 and PM11 inhibited in vitro ADP-induced aggregation by 44.0 ± 4.3% and 30.0 ± 3.2%, respectively, whereas PL, MF, and PM12 weakly or scarcely inhibited ADP-induced aggregation by 3.9 ± 3.2%, 13.0 ± 2.7%, and 5.2 ± 1.3%, respectively. The IC₅₀ values of PM21 on ADP-, collagen-, and thrombin-induced platelet aggregations were 135.6 ± 7.4 μg/mL, 142.7 ± 5.8 μg/mL, and 186.5 ± 9.7 μg/mL, respectively. In an in vivo rat arteriovenous-shunt thrombosis model, thrombus weight was significantly decreased after the oral administration of 400 mg/kg PL (27.8 ± 3.0%, p < 0.01) or MF (35.2 ± 2.1%, p < 0.01), and with a good accord to the in vitro results, the combination of PL and MF in the ratio of 2:1, PM21 (60.9 ± 1.2%, p < 0.001), showed a superior antithrombotic effect to those of individual extracts. At dosages of 200 mg/kg, 100 mg/kg, and 50 mg/kg, PM21 dose-dependently decreased thrombosis weight (ED₅₀, 314 mg/kg).

Conclusion

These results suggest that combination preparations of PL and MF, especially their 2:1 combination, can increase antiplatelet and antithromboticeffects more than PL and MF alone, offering evidence for a potential novel combination antithrombotic therapy.

Blockade by ruthenium red of tissue factor-initiated coagulation

The ability of ruthenium red (RuR) to inhibit tissue factor (TF)-initiated blood coagulation was demonstrated at the protein and cellular levels as well as in human plasma. In a single-stage clotting assay, RuR concentration-dependently inhibited rabbit brain thromboplastin (rbTF)-induced coagulation and offset bacterial endotoxin (LPS)-induced monocytic TF (mTF) hypercoagulation; the IC(50)s were estimated at 7.5 and 12.3 microM, respectively. A 15-min preincubation of RuR with rbTF or monocyte suspension resulted in the pronounced inhibition with a significantly lowered IC(50) at 1.8 or 7.7 microM for rbTF or mTF procoagulation, respectively. The differences in IC(50)s between rbTF and mTF without or with the preincubation indicated that TF was a primary target for RuR action. The effect of RuR on the physiological function of TF in FVII activation was demonstrated by the proteolytic cleavage of FVII zymogen to its active forms of serine protease on Western blotting analyses. RuR readily blocked TF-catalyzed FVII activation (diminished FVIIa formation), thus down regulating the initiation of blood coagulation. Inclusion of RuR into human plasma samples in vitro significantly prolonged prothrombin time, indicating the depressed coagulation. FVII activity was inhibited by 30 - 60% depending on the dose; as a result, FX activity also decreased. However, RuR showed no effect on thrombin time. Thus, RuR inhibited FVII activation to block the initiation of coagulation.