Recent progress and market analysis of anticoagulant drugs

Unveiling dynamics of nitrogen content and selected nitrogen heterocycles in thrombin inhibitors: a ceteris paribus approach

BACKGROUND

Despite the progress in comprehending molecular design principles and biochemical processes associated with thrombin inhibition, there is a crucial need to optimize efforts and curtail the recurrence of synthesis-testing cycles. Nitrogen and N-heterocycles are key features of many anti-thrombin drugs. Hence, a pragmatic analysis of nitrogen and N-heterocycles in thrombin inhibitors is important throughout the drug discovery pipeline. In the present work, the authors present an analysis with a specific focus on understanding the occurrence and distribution of nitrogen and selected N-heterocycles in the realm of thrombin inhibitors.

RESEARCH DESIGN AND METHODS

A dataset comprising 4359 thrombin inhibitors is used to scrutinize various categories of nitrogen atoms such as ring, non-ring, aromatic, and non-aromatic. In addition, selected aromatic and aliphatic N-heterocycles have been analyzed.

RESULTS

The analysis indicates that ~62% of thrombin inhibitors possess five or fewer nitrogen atoms. Substituted N-heterocycles have a high occurrence, like pyrrolidine (23.24%), pyridine (20.56%), piperidine (16.10%), thiazole (9.61%), imidazole (7.36%), etc. in thrombin inhibitors.

CONCLUSIONS

The majority of active thrombin inhibitors contain nitrogen atoms close to 5 and a combination of N-heterocycles like pyrrolidine, pyridine, piperidine, etc. This analysis provides crucial insights to optimize the transformation of lead compounds into potential anti-thrombin inhibitors.

Isocyanide-based multicomponent reactions for the synthesis of benzopyran derivatives with biological scaffolds

Benzopyrans (BZPs) are among the most privileged and influential small O-heterocycles that form the core of many natural compounds, commercial drugs, biological compositions, agrochemicals, and functional materials. BZPs are divided into six general categories including coumarins, chromans, 2H-chromenes, 4H-chromenes, chromones, and 4-chromanones, each of which is abundant in many plants and foods. These oxygenated heterocyclic compounds are fascinating motifs and have extensive applications in biology and materials science. Hence, numerous efforts have been made to develop innovative approaches for their extraction and synthesis. However, most of them are step-by-step or multi-step strategies that suffer from waste material generation and a tedious extraction process. Isocyanide-based multicomponent reactions (I-MCRs) offer a highly efficient method for overcoming these problems. The I-MCR is a simple and environmentally friendly one-pot domino procedure that does not require intermediate isolation or workup and is generally more efficient in material usage. This review covers all research articles related to I-MCRs for synthesizing BZP derivatives from the beginning to the middle of the year 2023. This strategy will be useful for organic and pharmaceutical chemists to design new drugs and optimize the synthesis steps of biological compounds and commercial drugs with benzopyran cores.

Orally administrated fucoidan and its low-molecular-weight derivatives are absorbed differentially to alleviate coagulation and thrombosis

Thrombosis is a serious threat to human health and life. Fucoidan, a sulfated polysaccharide from brown algae, could prevent coagulation and thrombus after intravenous administration. However, more efforts are still needed to develop its oral agent. In the present study, the absorption and excretion of fucoidan (90.8 kDa) and its degradation products, Dfuc1 (19.2 kDa) and Dfuc2 (5.5 kDa), were determined by HPLC-MS/MS after acid degradation and 1-phenyl-3-methyl-5-pyrazolone derivatization, and their anticoagulation and antithrombotic activities were evaluated in vivo after oral administration. Results showed that the maximum concentrations of fucoidan, Dfuc1 and Dfuc2 in rat plasma all achieved at 2 h after oral administration (150 mg/kg), and they were 41.1 ± 10.6 μg/mL, 45.3 ± 18.5 μg/mL and 59.3 ± 13.7 μg/mL, respectively. In addition, fucoidan, Dfuc1 and Dfuc2 could all prolong the activated partial thromboplastin time in vivo from 23.7 ± 2.7 s (blank control) to 25.1 ± 2.6 s, 27.1 ± 1.7 s and 29.4 ± 3.6 s, respectively. Moreover, fucoidan and its degradation products showed similar antithrombotic effect in carrageenan-induced thrombosis mice, and untargeted metabolomics analysis revealed that they all markedly regulated the carrageenan-induced metabolite disorders, especially the arachidonic acid metabolism. Thus, the degradation products of fucoidan with lower molecular weights are more attractive for the development of oral antithrombotic agents.

11,12-seco-Abietane-type diterpene lactones with potential antiplatelet activity from Salvia prattii

Eleven new abietane-type diterpene lactones, salpratlactones D-N (1-11), including five 11,12-seco-11-nor-abietane diterpenes (1-5), four 11,12-seco-abietane diterpenes (6-9), two 20(10 → 5)-abeo-4,5;11,12-bis-seco-abietane diterpenes (10-11), and two known analogues (12-13), were characterized from Salvia prattii. Notably, compounds 1-3 were characterized by a unique linear 6/6/6 tricyclic skeleton. The structures were established by spectroscopic data interpretation, calculated NMR-DP4+ and electronic circular dichroism analysis, as well as single-crystal X-ray diffraction. A bioactivity study showed that 1, 2, 5, 11, and 12 can potently inhibit platelet aggregation induced by arachidonic acid (AA), with IC50 values of 5.66-16.10 μg/ml, stronger than aspirin. In addition, the lactate dehydrogenase assay showed that they had no effect on platelet integrity. Structurally, the same 1,2-benzopyrone fragments of 1, 2, and 5 should be the important pharmacophore for antiplatelet activity.

Research Progress of Macromolecules in the Prevention and Treatment of Sepsis

Sepsis is associated with high rates of mortality in the intensive care unit and accompanied by systemic inflammatory reactions, secondary infections, and multiple organ failure. Biological macromolecules are drugs produced using modern biotechnology to prevent or treat diseases. Indeed, antithrombin, antimicrobial peptides, interleukins, antibodies, nucleic acids, and lentinan have been used to prevent and treat sepsis. In vitro, biological macromolecules can significantly ameliorate the inflammatory response, apoptosis, and multiple organ failure caused by sepsis. Several biological macromolecules have entered clinical trials. This review summarizes the sources, efficacy, mechanism of action, and research progress of macromolecular drugs used in the prevention and treatment of sepsis.

A Descriptive Analysis of Direct Oral Anticoagulant Drugs Dosing Errors Based on Spontaneous Reports from the EudraVigilance Database

Direct oral anticoagulant drugs (DOACs) interfere with the coagulation process, thus improving patient care for those who require anticoagulant treatment. This study presents a descriptive analysis of adverse reactions (ADRs) attributed to DOAC dosage errors (overdose, underdose, and improper dose). The analysis was performed based on the Individual Case Safety Reports from the EudraVigilance (EV) database. Results show that data reported for rivaroxaban, apixaban, edoxaban, and dabigatran are mostly regarding underdosing (51.56%) compared to overdosing (18.54%). The most dosage error reports were identified for rivaroxaban (54.02%), followed by apixaban (33.61%). Dabigatran and edoxaban had similar percentages (6.26% and 6.11%, respectively) regarding dosage error reports. Since coagulation issues can become life-threatening events, and factors such as advanced age and renal failure can influence the pharmacokinetics of drugs, the correct usage of DOACs is of utmost importance for the management and prevention of venous thromboembolism. Thus, the collaboration and the complementarity of knowledge of physicians and pharmacists may offer a reliable solution for DOAC dose management and improve patient care.

Integrated metabolomics and molecular docking reveal berberrubine inhibits thrombosis by regulating the vitamin K catalytic cycle in mice

OBJECTIVE

Natural product berberine was reported to inhibit platelet activation and thrombosis by suppressing the class Ⅰ PI3Kβ/Rasa3/Rap1 pathway. This study aims to investigate the effects and mechanisms of berberrubine, a main metabolite of berberine, to inhibit thrombus formation.

METHODS

Carrageenan-induced mouse tail thrombosis model was used to evaluate the effects of berberrubine hydrochloride (BBB) on thrombus formation in vivo. Non-targeted metabolomics was performed with UPLC-Q-TOF/MS to explore the potential mechanisms of BBB in inhibiting thrombosis. The effects of BBB on bleeding risk and prothrombin time were determined. And molecular docking was used to identify the possible target of BBB.

RESULTS

After oral administration, BBB significantly inhibited carrageenan-induced thrombosis in mice without prolonging bleeding time. The results of non-targeted metabolomics showed that oral BBB could regulate 'Phenylalanine, tyrosine and tryptophan biosynthesis' and 'Ubiquinone and other terpenoid-quinone biosynthesis', which is closely related to the vitamin K catalytic cycle. Molecular docking revealed BBB could combine and interact with vitamin K epoxide reductase (VKOR) and γ-Glutamyl carboxylase (GGCX), which was mutually confirmed with the experimental results that oral BBB could significantly prolong prothrombin time.

CONCLUSIONS

Integrated metabolomics and molecular docking reveal BBB inhibited thrombosis by regulating the vitamin K catalytic cycle. Our research is helpful in deeply understanding the antithrombotic material basis of oral berberine, and also could provide scientific evidence for developing new antithrombotic drugs based on BBB in the future.

Critical Quality Control Methods for a Novel Anticoagulant Candidate LFG-Na by HPSEC-MALLS-RID and Bioactivity Assays

A low molecular weight fucosylated glycosaminoglycan sodium (LFG-Na) is a novel anticoagulant candidate from the sea cucumber Holothuria fuscopunctata that selectively inhibits intrinsic tenase (iXase). The molecular weight, molecular weight distribution and bioactivities are the critical quality attributes of LFG-Na. The determination of these quality attributes of such an oligosaccharides mixture drug is challenging but critical for the quality control process to ensure its safety and efficacy in clinical use. Herein, the molecular weight and molecular weight distribution of LFG-Na were successfully determined using high performance size exclusion chromatography coupled with multi angle laser light scattering and refractive index detector (HPSEC-MALLS-RID). Comparing to the conventional method, HPSEC-MALLS-RID based on the refractive index increment (dn/dc) did not require the reference substances to establish the calibration curve. The acceptance criteria of LFG-Na were established, the weight-average molecular weight (Mw) should be 4000 to 6000 Da, the polydispersity (Mw/Mn) < 1.40, and the fraction with molecular weights of 1500 to 8000 Da should be no less than 80% of the total. HPSEC-MALLS-RID was also utilized for the determination of the starting material native fucosylated glycosaminoglycan (NFG) to choose a better manufacturing process. Furthermore, APTT assay was selected and the potency of anti-iXase, referring to the parallel line assay (PLA) method, was established to clarify the consistency of its biological activities. The results suggest that HPSEC-MALLS-RID and bioactivity assays are critical quality control methods for multi-component glycosaminoglycan LFG-Na. The methods also provide a feasible strategy to control the quality of other polysaccharide medicines.

Molecular dynamic and pharmacological studies on protein-engineered hirudin variants of Hirudinaria manillensis and Hirudo medicinalis

BACKGROUND AND PURPOSE

Hirudin variants are the most powerful thrombin inhibitors discovered to date, with a lower risk of bleeding than heparin. For anticoagulation, the C-termini of hirudins bind to the exocite I of thrombin. Anticoagulant effects of gene-recombinant hirudin are weaker than natural hirudin for the reason of lacking tyrosine-O-sulfation at C terminus.

EXPERIMENTAL APPROACH

The integrative pharmacological study applied molecular dynamic, molecular biological, and in vivo and in vitro experiments to elucidate the anticoagulant effects of protein-engineered hirudins.

KEY RESULTS

Molecular dynamic (MD) analysis showed that modifications of the C-termini of hirudin variant 1 of Hirudo medicinalis (HV1) and hirudin variant 2 of Hirudinaria manillensis (HM2) changed the binding energy of the C-termini to human thrombin. The study indicated Asp61 of HM2 that corresponds to sulfated Tyr63 of HV1 is critical for inhibiting thrombin activities, and the anticoagulant effects of HV1 and HM2 were improved when the amino acid residues adjacent to Asp61 were mutated to Asp, such as the prolongation of the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) of human blood, and decreased Ki and IC₅₀ values. In the in vivo experiments, mutations at C-termini of HV1 and HM2 significantly changed APTT, PT and TT.

CONCLUSION AND IMPLICATIONS

The study indicated that the anticoagulant effects of gene-engineered HM2 are stronger than gene-engineered HV1, and HM2-E60D-I62D has the strongest effects and could be an antithrombotic medicine with better therapeutic effects.

Bromelain, a Group of Pineapple Proteolytic Complex Enzymes (Ananas comosus) and Their Possible Therapeutic and Clinical Effects. A Summary

Bromelain is a complex combination of multiple endopeptidases of thiol and other compounds derived from the pineapple fruit, stem and/or root. Fruit bromelain and stem bromelain are produced completely distinctly and comprise unique compounds of enzymes, and the descriptor “Bromelain” originally referred in actuality to stem bromelain. Due to the efficacy of oral administration in the body, as a safe phytotherapeutic medication, bromelain was commonly suited for patients due to lack of compromise in its peptidase efficacy and the absence of undesired side effects. Various in vivo and in vitro studies have shown that they are anti-edematous, anti-inflammatory, anti-cancerous, anti-thrombotic, fibrinolytic, and facilitate the death of apoptotic cells. The pharmacological properties of bromelain are, in part, related to its arachidonate cascade modulation, inhibition of platelet aggregation, such as interference with malignant cell growth; anti-inflammatory action; fibrinolytic activity; skin debridement properties, and reduction of the severe effects of SARS-Cov-2. In this paper, we concentrated primarily on the potential of bromelain’s important characteristics and meditative and therapeutic effects, along with the possible mechanism of action.

Impact of anticoagulation and antiplatelet drugs on surgery rates and mortality in trauma patients

Preinjury anticoagulation therapy (AT) is associated with a higher risk for major bleeding. We aimed to evaluated the influence of preinjury anticoagulant medication on the clinical course after moderate and severe trauma. Patients in the TraumaRegister DGU ≥ 55 years who received AT were matched with patients not receiving AT. Pairs were grouped according to the drug used: Antiplatelet drugs (APD), vitamin K antagonists (VKA) and direct oral anticoagulants (DOAC). The primary end points were early (< 24 h) and total in-hospital mortality. Secondary endpoints included emergency surgical procedure rates and surgery rates. The APD group matched 1759 pairs, the VKA group 677 pairs, and the DOAC group 437 pairs. Surgery rates were statistically significant higher in the AT groups compared to controls (APD group: 51.8% vs. 47.8%, p = 0.015; VKA group: 52.4% vs. 44.8%, p = 0.005; DOAC group: 52.6% vs. 41.0%, p = 0.001). Patients on VKA had higher total in-hospital mortality (23.9% vs. 19.5%, p = 0.026), whereas APD patients showed a significantly higher early mortality compared to controls (5.3% vs. 3.5%, p = 0.011). Standard operating procedures should be developed to avoid lethal under-triage. Further studies should focus on detailed information about complications, secondary surgical procedures and preventable risk factors in relation to mortality.

Modification strategies to improve the membrane hemocompatibility in extracorporeal membrane oxygenator (ECMO)

ABSTRACT

Since extracorporeal membrane oxygenator (ECMO) has been utilized to save countless lives by providing continuous extracorporeal breathing and circulation to patients with severe cardiopulmonary failure. In particular, it has played an important role during the COVID-19 epidemic. One of the important composites of ECMO is membrane oxygenator, and the core composite of the membrane oxygenator is hollow fiber membrane, which is not only a place for blood oxygenation, but also is a barrier between the blood and gas side. However, the formation of blood clots in the oxygenator is a key problem in the using process. According to the study of the mechanism of thrombosis generation, it was found that improving the hemocompatibility is an efficient approach to reduce thrombus formation by modifying the surface of materials. In this review, the corresponding modification methods (surface property regulation, anticoagulant grafting, and bio-interface design) of hollow fiber membranes in ECMO are classified and discussed, and then, the research status and development prospects are summarized.

Evolving Paradigm of Prothrombin Time Diagnostics with Its Growing Clinical Relevance towards Cardio-Compromised and COVID-19 Affected Population

Prothrombin time (PT) is a significant coagulation (hemostasis) biomarker used to diagnose several thromboembolic and hemorrhagic complications based on its direct correlation with the physiological blood clotting time. Among the entire set of PT dependents, candidates with cardiovascular ailments are the major set of the population requiring lifelong anticoagulation therapy and supervised PT administration. Additionally, the increasing incidence of COVID affected by complications in coagulation dynamics has been strikingly evident. Prolonged PT along with sepsis-induced coagulopathy (SIC score > 3) has been found to be very common in critical COVID or CAC-affected cases. Considering the growing significance of an efficient point-of-care PT assaying platform to counter the increasing fatalities associated with cardio-compromised and coagulation aberrations propping up from CAC cases, the following review discusses the evolution of lab-based PT to point of care (PoC) PT assays. Recent advances in the field of PoC PT devices utilizing optics, acoustics, and mechanical and electrochemical methods in microsensors to detect blood coagulation are further elaborated. Thus, the following review holistically aims to motivate the future PT assay designers/researchers by detailing the relevance of PT and associated protocols for cardio compromised and COVID affected along with the intricacies of previously engineered PoC PT diagnostics.

Research Trends in Anticoagulation Therapy over the Last 25 Years

A large volume of literature has become available to practitioners prescribing anticoagulants. The aim of this study was to analyze the bibliometric characteristics of the top 100 most cited articles related to anticoagulation over the past 25 years, with special consideration to impact of direct or "nonvitamin K antagonist" oral anticoagulants (NOACs) compared with vitamin K antagonists. A bibliometric analysis of the 100 most cited journal articles related to anticoagulants published between 1994 and 2019 was performed in April 2019. The top 100 articles by citation count were analyzed to extract bibliometric data related to journal title, impact factor, year of publication, place of publication, anticoagulant studied, indication for anticoagulation, study design, and conflicts of interest. The median (interquartile range) number of citations per article was 806 (621-1,085). The anticoagulant most frequently researched was warfarin (37%). NOAC publications (21%) grew at a relative rate of 3.4 times faster compared with all publications. The indication most commonly researched was venous thromboembolism (26%). Eighty articles constituted level I or II evidence, with randomized controlled trials the most common type of study (74). A financial conflict of interest was declared in 87% of articles with private, for-profit organizations the most common source of funding (26%). In summary, top research related to anticoagulation is highly impactful but may be at risk of sponsorship bias. High-level evidence for NOACs continues to expand across a range of indications with citation metrics likely to soon approach or surpass that of older drugs.

Identification and analysis of transepithelial transport properties of casein peptides with anticoagulant and ACE inhibitory activities

Casein is an excellent source for producing anticoagulant and angiotensin I-converting enzyme inhibitory (ACEI) peptides. Here, the anticoagulant and ACEI activities of the casein hydrolysate produced by in vitro simulated gastrointestinal (GI) digestion were evaluated. The casein hydrolysate showed potent anticoagulant activity by prolonging the thrombin time (TT) and activated partial thromboplastin time (APTT), and also presenting great ACEI activity, with an IC₅₀ value of 0.52 mg mL^-1. Subsequently, the transepithelial transport properties of the casein hydrolysate were analyzed by using the Caco-2 cell monolayer model. The peptides profile of the casein hydrolysate before and after it passed across the Caco-2 cell monolayer were identified by NanoLC-Q-TOF-MS/MS. The results showed that a total of 121 and 184 peptides were identified before and after casein hydrolysate moved through the Caco-2 cell monolayer, respectively. Eighty peptides were presented at both time points of the transport study. Among the 80 peptides, 26 of them were screened with a high possibility of exerting physiological roles after they were absorbed into the blood by in silico methods, and the physicochemical characteristics, e.g., hydrophobicity, net charge, and toxicity of the peptides also be evaluated. Our results provided a new prospect and approach for producing bioactive peptides from casein with anticoagulant and ACEI activities.

Investigations in ultrasound-assisted anticoagulant production by marine Bacillus subtilis ZHX

Anticoagulants are the main drugs for the prevention and treatment of thromboembolism. However, most of the present anticoagulants have shortcomings and novel anticoagulants are in great demand. Marine microorganisms are an important source of new drugs. Therefore, in this study, ultrasound was applied to enhance anticoagulant accumulation by marine Bacillus subtilis ZHX. Ultrasound parameters were optimized by single-factor experiments exploring the effects of ultrasound power, duration, duty cycle and the cell growth phases. The optimum conditions were exponential prophase (5 h) with 25 kHz frequency, 140 W power, and a 40% duty cycle for 5 min. The maximum anticoagulant activity (55.36 U/mL) was 1.73 times that of the control group, and the fermentation time was shortened by 3 h. Under optimal conditions, ultrasound increased the carbon utilization by Bacillus subtilis ZHX without significant changes in morphology, favoring cell growth and anticoagulant production. However, excessive ultrasound caused intracellular damage, which inhibited biomass accumulation, decreasing anticoagulant activity and even leading to cell rupture. This is the first report on the use of ultrasound to enhance anticoagulant production by Bacillus, and it provides useful information for scaling-up the process.

Microfluidics in Haemostasis: A Review

Haemostatic disorders are both complex and costly in relation to both their treatment and subsequent management. As leading causes of mortality worldwide, there is an ever-increasing drive to improve the diagnosis and prevention of haemostatic disorders. The field of microfluidic and Lab on a Chip (LOC) technologies is rapidly advancing and the important role of miniaturised diagnostics is becoming more evident in the healthcare system, with particular importance in near patient testing (NPT) and point of care (POC) settings. Microfluidic technologies present innovative solutions to diagnostic and clinical challenges which have the knock-on effect of improving health care and quality of life. In this review, both advanced microfluidic devices (R&D) and commercially available devices for the diagnosis and monitoring of haemostasis-related disorders and antithrombotic therapies, respectively, are discussed. Innovative design specifications, fabrication techniques, and modes of detection in addition to the materials used in developing micro-channels are reviewed in the context of application to the field of haemostasis.

The Role of CYP450 Drug Metabolism in Precision Cardio-Oncology

As many novel cancer therapies continue to emerge, the field of Cardio-Oncology (or onco-cardiology) has become crucial to prevent, monitor and treat cancer therapy-related cardiovascular toxicity. Furthermore, given the narrow therapeutic window of most cancer therapies, drug-drug interactions are prevalent in the cancer population. Consequently, there is an increased risk of affecting drug efficacy or predisposing individual patients to adverse side effects. Here we review the role of cytochrome P450 (CYP450) enzymes in the field of Cardio-Oncology. We highlight the importance of cardiac medications in preventive Cardio-Oncology for high-risk patients or in the management of cardiotoxicities during or following cancer treatment. Common interactions between Oncology and Cardiology drugs are catalogued, emphasizing the impact of differential metabolism of each substrate drug on unpredictable drug bioavailability and consequent inter-individual variability in treatment response or development of cardiovascular toxicity. This inter-individual variability in bioavailability and subsequent response can be further enhanced by genomic variants in CYP450, or by modifications of CYP450 gene, RNA or protein expression or function in various 'omics' related to precision medicine. Thus, we advocate for an individualized approach to each patient by a multidisciplinary team with clinical pharmacists evaluating a treatment plan tailored to a practice of precision Cardio-Oncology. This review may increase awareness of these key concepts in the rapidly evolving field of Cardio-Oncology.

Wastewater-borne exposure of limnic fish to anticoagulant rodenticides

The recent emergence of second-generation anticoagulant rodenticides (AR) in the aquatic environment emphasizes the relevance and impact of aquatic exposure pathways during rodent control. Pest control in municipal sewer systems of urban and suburban areas is thought to be an important emission pathway for AR to reach wastewater and municipal wastewater treatment plants (WWTP), respectively. To circumstantiate that AR will enter streams via effluent discharges and bioaccumulate in aquatic organisms despite very low predicted environmental emissions, we conducted a retrospective biological monitoring of fish tissue samples from different WWTP fish monitoring ponds exclusively fed by municipal effluents in Bavaria, Germany. At the same time, information about rodent control in associated sewer systems was collected by telephone survey to assess relationships between sewer baiting and rodenticide residues in fish. In addition, mussel and fish tissue samples from several Bavarian surface waters with different effluent impact were analyzed to evaluate the prevalence of anticoagulants in indigenous aquatic organisms. Hepatic AR residues were detected at 12 out of 25 WWTP sampling sites in the low μg/kg range, thereof six sites with one or more second-generation AR (i.e., brodifacoum, difenacoum, bromadiolone). 14 of 18 surveyed sites confirmed sewer baiting with AR and detected hepatic residues matched the reported active ingredients used for sewer baiting at six sites. Furthermore, second-generation AR were detected in more than 80% of fish liver samples from investigated Bavarian streams. Highest total hepatic AR concentrations in these fish were 9.1 and 8.5 μg/kg wet weight, respectively and were observed at two riverine sampling sites characterized by close proximity to upstream WWTP outfalls. No anticoagulant residues were found in fish liver samples from two lakes without known influences of effluent discharges. The findings of our study clearly show incomplete removal of anticoagulants during conventional wastewater treatment and confirm exposure of aquatic organisms via municipal effluents. Based on the demonstrated temporal and spatial coherence between sewer baiting and hepatic AR residues in effluent-exposed fish, sewer baiting in combined sewer systems contributes to the release of active ingredients into the aquatic environment.

Synthesis, characterization and anticoagulant activity of chitosan derivatives

Chitosan derivatives are reported as anticoagulants in the literature. This work was undertaken to develop novel chitosan derivatives as anticoagulants. The sulfonated derivatives of chitosan were formed by the reaction of chitosan derivatives with chlorosulfonic acid in N,N-dimethylformamide. The structures of these derivatives were established by FTIR and ¹H NMR spectra. The prepared derivatives were evaluated for their in vivo anticoagulant effects by the tail bleeding method in Wistar rats utilizing nicoumalone as a standard drug. The results revealed that the sulfonation of the chitosan increases its anticoagulant activity. The developed compounds exhibited faster onset of action and potency than nicoumalone after one hour of the drug administration. The sulphated N-alkyl derivatives of chitosan were more potent anticoagulants than sulfated quaternary derivatives/sulfated chitosan. It is also suggested to develop analogs of Ethyl chitosan sulfate (4b) and Benzyl chitosan sulfate (4c), which may provide some more fruitful anticoagulants having faster onset of action as well as longer duration of action and possessing a balanced hydrophilic/lipophilic character.

Rapid assembly and profiling of an anticoagulant sulfoprotein library

Hematophagous organisms produce a suite of salivary proteins which interact with the host's coagulation machinery to facilitate the acquisition and digestion of a bloodmeal. Many of these biomolecules inhibit the central blood-clotting serine proteinase thrombin that is also the target of several clinically approved anticoagulants. Here a bioinformatics approach is used to identify seven tick proteins with putative thrombin inhibitory activity that we predict to be posttranslationally sulfated at two conserved tyrosine residues. To corroborate the biological role of these molecules and investigate the effects of amino acid sequence and sulfation modifications on thrombin inhibition and anticoagulant activity, a library of 34 homogeneously sulfated protein variants were rapidly assembled using one-pot diselenide-selenoester ligation (DSL)-deselenization chemistry. Downstream functional characterization validated the thrombin-directed activity of all target molecules and revealed that posttranslational sulfation of specific tyrosine residues crucially modulates potency. Importantly, access to this homogeneously modified protein library not only enabled the determination of key structure-activity relationships and the identification of potent anticoagulant leads, but also revealed subtleties in the mechanism of thrombin inhibition, between and within the families, that would be impossible to predict from the amino acid sequence alone. The synthetic platform described here therefore serves as a highly valuable tool for the generation and thorough characterization of libraries of related peptide and/or protein molecules (with or without modifications) for the identification of lead candidates for medicinal chemistry programs.

Platelet integrin αIIbβ3: signal transduction, regulation, and its therapeutic targeting

Integrins are a family of transmembrane glycoprotein signaling receptors that can transmit bioinformation bidirectionally across the plasma membrane. Integrin αIIbβ3 is expressed at a high level in platelets and their progenitors, where it plays a central role in platelet functions, hemostasis, and arterial thrombosis. Integrin αIIbβ3 also participates in cancer progression, such as tumor cell proliferation and metastasis. In resting platelets, integrin αIIbβ3 adopts an inactive conformation. Upon agonist stimulation, the transduction of inside-out signals leads integrin αIIbβ3 to switch from a low- to high-affinity state for fibrinogen and other ligands. Ligand binding causes integrin clustering and subsequently promotes outside-in signaling, which initiates and amplifies a range of cellular events to drive essential platelet functions such as spreading, aggregation, clot retraction, and thrombus consolidation. Regulation of the bidirectional signaling of integrin αIIbβ3 requires the involvement of numerous interacting proteins, which associate with the cytoplasmic tails of αIIbβ3 in particular. Integrin αIIbβ3 and its signaling pathways are considered promising targets for antithrombotic therapy. This review describes the bidirectional signal transduction of integrin αIIbβ3 in platelets, as well as the proteins responsible for its regulation and therapeutic agents that target integrin αIIbβ3 and its signaling pathways.