Assessment of low plasma concentrations of apixaban in the periprocedural setting.

INTRODUCTION: Estimation of residual apixaban plasma concentrations may be requested in the management of emergencies. This study aims at assessing the performance of specific anti-Xa assays calibrated with apixaban on real-life samples with low apixaban plasma concentrations (<30 ng/mL) and on-treatment ranges, with and without interference of low-molecular-weight heparin (LMWH). METHODS: The performance of the STA® -Liquid Anti-Xa assay (STA® LAX) and the low and normal procedures of the Biophen® Direct Factor Xa Inhibitors (DiXaI) assay was tested on 134 blood samples, collected from patients on apixaban, wherefrom 74 patients received LMWH after apixaban cessation. The results were compared with the liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) measurements. RESULTS: The Biophen® DiXaI, Biophen® DiXaI LOW, and STA® LAX showed very good correlation with LC-MS/MS measurements in patients without LMWH administration (Spearman r .95, .99, and .98, respectively). Their limits of quantitation were defined at 48, 24, and 12 ng/mL, respectively. The Bland-Altman test measured mean bias (SD) at 5.6 (13.1), -2.5 (5.0), and -0.8 (6.1) ng/ml, respectively. The Spearman r of the Biophen® DiXaI decreased to 0.64 in presence of low apixaban concentrations. The Spearman r of the Biophen® DiXaI LOW and STA® LAX decreased to 0.39 and 0.26, respectively, in presence of LMWH. CONCLUSIONS: The accuracy of the low methodologies (Biophen® DiXaI LOW and STA® LAX) is slightly improved for low apixaban plasma concentrations, compared with the normal procedure of Biophen® DiXaI. The interference of LMWH on the low methodologies is measurable, however, less important than the previously reported interference of LMWH on rivaroxaban calibrated specific anti-Xa assays.

Self-Propelled Gemini-like LMWH-Scaffold Nanodrugs for Overall Tumor Microenvironment Manipulation via Macrophage Reprogramming and Vessel Normalization.

Angiogenesis is the hallmark of melanoma that nurtures the tumor microenvironment (TME) for rapid tumor progression. Vessel normalization could benefit melanoma treatment through TME reconstruction, while its limited duration and extent are still the drag. Herein, two kinds of look-like nanodrugs, called Gemini-like nanodrugs (GLnano), were constructed separately with the same scaffold of antiangiogenic low molecular weight heparin (LMWH) and mixed upon administration in vivo. For one, doxorubicin (DOX) was encapsulated into LMWH-chrysin nanodrug (LCY) with DSPE-PEG-anisamide decoration (D-LCA nanodrugs) for active targeting and direct cell killing toward melanoma cells. For another, matrix metalloproteinases (MMPs)-sensitive peptide was conjugated to LMWH to encapsulate celecoxib (Cel) (C-Lpep nanodrugs), disassembling in TME by MMPs and releasing Cel for M2-to-M1 reprogramming of tumor-associated macrophages. Our results showed that GLnano could remarkably elongate the vessel normalization window up to 12 days with the highest pericyte coverage of nearly 75%, compared to only 4 days by LCY monotherapy. Furthermore, GLnano could spontaneously form the "treatment-delivery" loop to promote nanodrugs toward deep tumor regions, leading to a potent tumor inhibition, metastasis prevention, and overall TME improvements.

Liver histopathological findings in advanced heart failure: a reappraisal of cardiac cirrhosis concept.

Cardiogenic liver disease is a common yet poorly characterized complication of advanced heart failure (HF), and may impact clinical management in the setting of heart transplant evaluation. In this retrospective study, we describe clinical and histopathological features of liver injury in advanced HF, with a focus on the role of liver biopsy. Included were 45 HF patients, assessed for possible heart transplant, who underwent liver biopsy for suspected liver disease. Median duration of HF symptoms was 5 years. Most patients had stiff hepatomegaly and elevated bilirubin. Viral hepatitis (19 patients, 42.2%) was the most common cause of prior known liver disease. Sinusoidal dilatation was detected in the majority of patients (64.4%). Median necroinflammatory index was 3 and median fibrosis was 1, consistent with a small burden of histologically proven liver disease. Viral hepatitis was the only variable associated with a higher grade of necroinflammation and fibrosis. Nine of the 14 (64.3%) advanced fibrosis/cirrhosis patients had a viral hepatitis infection. Fibrosis was significantly associated with splenomegaly. The MELD score was not correlated with cardiac index. A coarse liver echo-pattern had a 29% positive and 63% negative predictive value for advanced fibrosis/cirrhosis. Severe liver disease is uncommon in patients with advanced HF in the absence of splenomegaly or primary causes of liver disease. Ultrasound data need to be carefully evaluated, as it may overstate the severity of liver disease. Liver biopsy may be needed to accurately stage liver disease before excluding patients from advanced treatment strategies.

Anti-tumour activity of low molecular weight heparin doxorubicin nanoparticles for histone H1 high-expressive prostate cancer PC-3M cells.

Nucleus-targeting drug delivery systems (NTDDs) deliver chemotherapeutic agents to nuclei in order to improve the efficacy of anti-tumour therapy. Histone H1 (H1) plays a key role in establishing and maintaining higher order chromatin structures and could bind to cell membranes. In the present study, we selected H1 as a target to prepare a novel H1-mediated NTDD. Low molecular weight heparin (LMHP) and doxorubicin (DOX) were combined to form LMHP-DOX. Then, a novel NTDD consisting of LMHP-DOX nanoparticles (LMHP-DOX NPs) was prepared by self-assembly. The characteristics of LMHP-DOX and LMHP-DOX NPs were investigated. Histone H1 high-expressive prostate cancer PC-3M cell line was selected as the cell model. Cellular uptake, and the in vitro and in vivo anti-tumour activity of LMHP-DOX NPs were evaluated on H1 high-expressive human prostate cancer PC-3M cells. Our results indicated that intact LMHP-DOX NPs mediated by H1 could be absorbed by H1 high-expressive PC-3M cells, escape from the lysosomes to the cytoplasm, and localize in the perinuclear region via H1-mediated, whereby DOX could directly enter the cell nucleus and quickly increase the concentration of DOX in the nuclei of H1 high-expressive PC-3M cells to enhance the apoptotic activity of cancer cells. The anti-coagulant activity of LMHP-DOX NPs was almost completely diminished in rat blood compared with that of LMHP, indicating the safety of LMHP-DOX NPs. Compared to traditional NTDD strategies, LMHP-DOX NPs avoid the complicated modification of nucleus-targeting ligands and provide a compelling solution for the substantially enhanced nuclear uptake of chemotherapeutic agents for the development of more intelligent NTDDs.

Pleiotropic effects of heparins: does anticoagulant treatment increase survival in cancer patients?

The association between venous thromboembolism (VTE) and cancer has been recognized for more than 100 years. Numerous studies have been performed to investigate strategies to decrease VTE incidence and to establish whether treating VTE impacts cancer progression and overall survival. Accordingly, it is important to understand the role of the hemostatic system in tumorigenesis and progression, as there is abundant evidence associating it with cell survival and proliferation, tumor angiogenesis, invasion, and dissemination, and metastasis formation. In attempts to further the scientific evidence, several studies examine survival benefits in cancer patients treated with anticoagulant therapy, specifically treatment with vitamin K antagonists, unfractionated heparin, and low-molecular-weight heparin. Several studies and meta-analyses have been conducted with a special focus on brain tumors. However, no definitive conclusions have been obtained, and more well-designed clinical trials are needed

No disponible

Self-assembled nanocomplex of PEGylated protamine and heparin-suramin conjugate for accumulation at the tumor site.

Heparin-like sulfated polysaccharides are potential drug candidates owing to their ability to interact with angiogenic factors and inhibit angiogenesis, tumor growth, and metastasis. This study aimed to improve the delivery of heparin-like anticancer polysaccharides for accumulation at the tumor site. We designed a nanocarrier system using protamine attached to polyethylene glycol (PEG) and evaluated the stability, tumor targeting, and tumor growth inhibition of the nanocarrier loaded with heparin derivatives. When mixed with various polyanionic heparin derivatives, the polycationic PEG-protamine formed stable self-assembled nanocomplexes via ionic interactions, with flexible PEG chains located on the outside. Among the complexes, a nanocomplex loaded with a low-molecular-weight heparin-suramin conjugate (LHsura) had the most suitable average size (101.9nm) for the enhanced permeability and retention effect and allowed accumulation of LHsura at the tumor site for up to 48h. In a tumor-bearing mouse model, the PEG-protamine and LHsura nanocomplex (10mg/kg/3days, intravenously), which could be extravasated through the tumor vasculature, significantly inhibited tumor growth, more than LHsura alone did. Overall, the self-assembled nanocomplexation of PEG-protamine and LHsura helped control the release and extravasation of LHsura, which resulted in an antitumor effect on the target tumor cells.

Estimation of Rivaroxaban Plasma Concentrations in the Perioperative Setting in Patients With or Without Heparin Bridging.

INTRODUCTION: Estimation of residual rivaroxaban plasma concentrations may be requested before invasive procedures and some patients at high thromboembolic risk will have a bridging therapy with heparins when rivaroxaban is interrupted. OBJECTIVE: The objective of this study was to assess the performance of the STA-Liquid Anti-Xa assay (STA LAX) and the low and normal procedures of the Biophen Direct Factor Xa Inhibitors (DiXaI) assay, in patients with and without bridging with low-molecular-weight heparins (LMWHs). MATERIALS AND METHODS: Seventy-nine blood samples were collected from 77 patients on rivaroxaban at CTROUGH or before an invasive procedure. Rivaroxaban plasma concentrations were estimated using Biophen DiXaI, Biophen DiXaI LOW, and STA LAX and compared to liquid chromatography coupled with mass spectrometry (LC-MS/MS) measurements. Stratifications were performed according to heparin bridging. RESULTS: The Biophen DiXaI LOW and STA LAX showed better correlation with LC-MS/MS measurements than Biophen DiXaI in patients not bridged with LMWH (R: 0.97, 0.96, and 0.91, respectively). However, the performance of Biophen DiXaI LOW and STA LAX decreased when residual LMWH activity was present (R: 0.18 and 0.19 respectively) demonstrating that these tests are not specific to rivaroxaban. CONCLUSION: In patients not bridged with LMWH, we suggest to use the Biophen DiXaI LOW and STA LAX for the estimation of rivaroxaban concentrations <50 ng/mL. These results should be confirmed on a larger cohort of patients. Patients bridged with LMWH have inaccurate estimates of low levels of rivaroxaban and the 3 assays studied should not be used to estimate if it is safe to perform a procedure.

Effects of Chitosan Derivative N-[(2-Hydroxy-3-Trimethylammonium)Propyl]Chloride on Anticoagulant Activity of Guinea Pig Plasma.

Intravenous injection of protamine sulfate or quarternized chitosan derivative to guinea pigs after injection of 70 aIIa U/kg non-fractionated heparin shortened plasma clotting time (shown by partial activated thromboplastin time, thrombin time, and prothrombin time). Intravenous injection of protamine sulfate or quarternized chitosan derivative to guinea pigs after injection of 1 mg/kg (100 aXa U/kg) low-molecular-weight heparin (clexane) led to shortening of plasma clotting time in the ReaClot Heparin test and to prolongation of plasma amidolytic activity in the factor Xa chromogenic substrate test.

Insight into the role of dual-ligand modification in low molecular weight heparin based nanocarrier for targeted delivery of doxorubicin.

Low molecular weight heparin nanoparticles (LMWH) modified by glycyrrhetinic acid (GA) (LMWH-GA) and further decorated by lactobionic acid (LA) (LA-LMWH-GA) were reported as novel hepatocellular carcinoma (HPC)-targeted carriers to overcome multidrug resistance (MDR) of doxorubicin (DOX). The drug-loaded nanoparticles had negative charge of around -25mV and average size range of 70-170nm. These nanoparticles performed sustained drug release in vitro and prolonged DOX residence time in blood circulation in vivo. Compared to free DOX, DOX-loaded nanoparticles demonstrated increased DOX accumulation in drug-resistance HepG2/ADR cells and enhanced in vitro therapeutic efficacy. However, DOX/LA-LMWH-GA with dual ligands didn't show higher cellular uptake and cytotoxicity than single GA modified DOX/LMWH-GA, although both GA-mediated and LA-mediated endocytosis were involved in their cell internalization. Uptake pathway inhibition study revealed the less efficacy of DOX/LA-LMWH-GA in cellular level could be attributed to the reduced effect of micropinocytosis and caveolae-mediated endocytosis in cellular uptake. Interestingly, the DOX-loaded nanoparticles developed from lower drug/carrier feeding ratio possessed higher performance in cell internalization and in vitro efficacy compared to those developed from higher drug/carrier feeding ratio, which could highlight the role of carrier in drug delivery process.

Gambogic acid grafted low molecular weight heparin micelles for targeted treatment in a hepatocellular carcinoma model with an enhanced anti-angiogenesis effect.

Gambogic acid (GA) is a potential anti-cancer agent with poor water-solubility, whereas heparin has anti-angiogenesis effects with good hydrophilicity. In this study, GA grafted low molecular weight heparin (GA-LMWH) was prepared and self-assembled into micelles in aqueous solution to improve the solubility and antitumor effects against hepatocellular carcinoma. The substitution of GA-LMWH is 27.5±0.2%. The micelles had a mean size of 190.4±10.8nm, a low critical micelle concentration of 2.4±0.2µgmL-1, and the highest area under the concentration-time curve and mean retention time in the liver compared to the heart, spleen, lung and kidney (p<0.05). The targeting efficiency of micelles to the liver is 2.1-times higher than that of the GA solution. GA-LMWH micelles were administered intravenously and significantly improved liver function, decreased cell lesions in hepatic tissue, inhibited the expression of CD105 and prolonged survival time of hepatocellular carcinoma model compared with groups treated with normal saline or GA solution. These results suggest that GA-LMWH micelles may improve anti-cancer effects by targeting the delivery of GA to the liver and enhancing the anti-angiogenesis effect.

Anticoagulation Therapy in Patients with Chronic Kidney Disease.

Patients with chronic kidney disease (CKD) are at increased risk for both thrombotic events and bleeding. The early stages of CKD are mainly associated with prothrombotic tendency, whereas in its more advanced stages, beside the prothrombotic state, platelets can become dysfunctional due to uremic-related toxin exposure leading to an increased bleeding tendency. Patients with CKD usually require anticoagulation therapy for treatment or prevention of thromboembolic diseases. However, this benefit could easily be offset by the risk of anticoagulant-induced bleeding. Treatment of patients with CKD should be based on evidence from randomized clinical trials, but usually CKD patients are excluded from these trials. In the past, unfractionated heparins were the anticoagulant of choice for patients with CKD because of its independence of kidney elimination. However, currently low-molecular-weight heparins have largely replaced the use of unfractionated heparins owing to fewer incidences of heparin-induced thrombocytopenia and bleeding. We undertook this review in order to explain the practical considerations for the management of anticoagulation in these high risk population.

Update on Direct Oral AntiCoagulants (DOACs).

Recent findings require an update of previous recommendations for the perioperative use of Direct Oral AntiCoagulants (DOACs). A break in preoperative treatment of 24-96 hours is recommended based on the pharmacokinetic profiles of DOACs and depends on individual patient characteristics, their renal and possibly liver function, and their surgery-related risk of bleeding. In cases of renal or hepatic insufficiency, whether to extend the preoperative interruption of IIa- and Xa-inhibitors is a clinical decision that must be reached on an individual patient basis. In cases of epidural or spinal anaesthesia, more conservative pausing-intervals are recommended due to the risk of persistent neurologic deficits (e.g., paraplegia) following the development of spinal subdural and epidural haematomas. Elective surgery should be postponed according to these recommendations. Preoperative "bridging" with LMWH (more precisely referred to as "switching") should be omitted due to a significantly increased risk of bleeding. In addition, the incidence of perioperative thromboembolic risks, such as DVT, PE, and stroke, are no different whether interruption or "switching" is undertaken. Postoperatively, the DOACs can be reinstituted within the first 24 hours. In cases of major surgery or if there is a higher risk of bleeding, resumption of DOACS should only begin after 24-72 hours. In patients with an elevated thromboembolic risk, transient postoperative LMWH administration can be recommended during this period.Interaction of DOACs with other drugs usually occurs during the absorption, transport and elimination of these drugs. Therefore, substance- specific restrictions and recommendations should be observed during these times. In everyday clinical practice, webbased, independent information portals on drug-interactions are very helpful in providing safe and rapid information about potential interactions when DOACs are used in combination with other drugs, especially during perioperative management.Non-adherence to medications is a worldwide problem that has dangerous and costly consequences. Present data suggest that persistence is the primary factor that supports adherence. Despite the adherence data presented in the DOACS approval studies (e.g., persistence in the treatment of acute venous thromboembolism has been reported to be between 94-99%), the first registries and meta-analyses provide sobering results regarding the incidence of persistence and the success rate of interventions designed to improve adherence with DOACs in cases of long-term usage.

Anti-Xa monitoring of low-molecular-weight heparin in adult patients with cancer.

A 68-year-old man developed a right femoral vein deep vein thrombosis and bilateral pulmonary embolism while receiving chemotherapy for stage IV prostate cancer. His creatinine at diagnosis is 1.4 mg/dL, with an estimated clearance of 63 mL/min. In patients with cancer, should low-molecular-weight heparin treatment be dosed according to weight, or adjusted using anti-Xa levels?

Cost-effectiveness analysis of apixaban compared to low-molecular-weight heparins and vitamin k antagonists for treatment and secondary prevention of venous thromboembolism / Coste-efectividad de apixaban versus heparinas y antagonistas de la vitamina k para el tratamiento y la prevención secundaria del tromboembolismo venoso

OBJECTIVE: Cost-effectiveness analysis of a 6-month treatment of apixaban (10 mg/12h, first 7 days; 5 mg/12h afterwards) for the treatment of the first event of venous thromboembolism (VTE) and prevention of recurrences, versus low-molecular-weight heparins/vitamin K antagonists treatment (LMWH/VKA). MATERIAL AND METHODS: A lifetime Markov model with 13 health states was used for describing the course of the disease. Efficacy and safety data were obtained from AMPLIFY and AMPLIFY-EXT clinical trials; health outcomes were measured as life years gained (LYG) and quality-adjusted life years (QALY). The chosen perspective of this analysis has been the Spanish National Health System (NHS). Drugs, management of VTE and complications costs were obtained from several Spanish data sources (€, 2014). A 3% discount rate was applied to health outcomes and costs. Univariate and probabilistic sensitivity analyses (SA) were performed in order to assess the robustness of the results. RESULTS: Apixaban was the most effective therapy with 7.182 LYG and 5.865 QALY, versus 7.160 LYG and 5.838 QALYs with LMWH/VKA. Furthermore, apixaban had a lower total cost (€13,374.70 vs €13,738.30). Probabilistic SA confirmed dominance of apixaban (led to better health outcomes with less associated costs) in 89% of the simulations. CONCLUSIONS: Apixaban 5 mg/12h versus LMWH/VKA was an efficient therapeutic strategy for the treatment and prevention of recurrences of VTE from the NHS perspective

OBJETIVO: Analizar la relación coste-efectividad de 6 meses de tratamiento con apixaban (10 mg/12 h, 7 primeros días; 5 mg/12 h después) para el primer evento de tromboembolismo venoso (TEV) y prevención de recurrencias, frente a heparinas de bajo peso molecular/antagonistas de vitamina K (HBPM/ AVK). MATERIAL Y MÉTODOS: Se ha empleado un modelo de Markov con 13 estados de salud que describen la evolución de la enfermedad a lo largo de la vida de los pacientes. Los datos de eficacia y seguridad se han obtenido de los ensayos clínicos AMPLIFY y AMPLIFY-EXT, calculándose los años de vida ganados (AVG) y los años de vida ajustados por calidad (AVAC) de las opciones terapéuticas evaluadas. En este análisis se adoptó la perspectiva del Sistema Nacional de Salud (SNS). El coste de la medicación, de las complicaciones y del manejo del TEV se obtuvo de distintas fuentes españolas (€, 2014). Se aplicó una tasa de descuento anual del 3% a costes y beneficios en salud. Se realizaron análisis de sensibilidad univariante y probabilístico (ASP) para evaluar la robustez de los resultados. RESULTADOS: Apixaban generó mejores resultados en salud con 7,182 AVG y 5,865 AVAC, frente a 7,160 AVG y 5,838 AVAC para HBPM/AVK, y con menor coste total (13.374,70 € versus 13.738,30 €). El ASP confirmó la dominancia de apixaban (produce mejores resultados con menores costes asociados) en el 89% de las simulaciones. CONCLUSIONES: Apixaban 5 mg/12 h versus HBPM/AVK fue una estrategia eficiente para el SNS en el tratamiento y prevención de recurrencias de TEV

Preparation and evaluation a new generation of low molecular weight heparin.

Enoxaparin is widely used in clinic, but it has some disadvantages. For example, its anticoagulant activity is weaker compared with heparin and it can not be effectively neutralizad by protamine sulfate (PS) in case of bleeding. Therefore, in this work, a new generation of low molecular weight heparin (NG-LMWH) was prepared.The NG-LMWH was prepared with the method of alkaline ß-elimination followed by gel chromatography. Estimating the molecular weight of the NG-LMWH by GPC-HPLC, it has a remarkably low polydispersity index and narrow molecular weight distribution. The polydispersity index of NG-LMWH was 1.052, which was lower than heparin (1.5) and enoxaparin (1.279). Anti-FXa and anti-FIIa potency of NG-LMWH was much higher than that of Enoxaparin, and close to that of heparin, which was determined by chromogenic substrate method. To test the degree of anti-FXa or anti-FIIa potency neutralized by PS, equivalent anti-FXa or anti-FIIa activity doses of different anticoagulant in plasma were titrated with increasing amounts of PS in plasma. The results indicate that NG-LMWH was more efficiently neutralized by PS than enoxaparin.The efficacy of anti-thrombus of NG-LMWH was superior to enoxaparin and the effect was dose dependent, which was evaluated with rat carotid artery thrombosis and inferior vena cava thrombosis model. The results of pharmacokinetics in New Zealand rabbits showed that the pharmacokinetic characteristics of NG-LMWH were similar to enoxaparin. The NG-LMWH prepared in this work has both advantages of heparin and enoxaparin with more effective and safer anticoagulation than enoxaparin.

Development of PEG-PLGA based Intravenous Low Molecular Weight Heparin (LMWH) Nanoparticles Intended to Treat Venous Thrombosis.

BACKGROUND: Anticoagulant therapy is effective in the treatment of DVT. In this regard, LMWH demonstrated significant promise. It is widely used clinically. The goal of this study was to prepare and evaluate intravenous sustained release stealth nanoparticles encapsulating LMWH using PLGA (polylactidecoglycolide) and different grades of PEG (poly ethylene glycols). METHODS: The nanoparticles were prepared using w/o/w solvent evaporation technique. Prepared nanoparticles were evaluated for particle size, encapsulation efficiency, in-vitro drug release, anti-thrombotic activity in venous thrombosis rat model, estimation of aPTT, tissue bio-distribution studies and stability. RESULTS: Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) studies confirmed the formation of smooth spherical particles. FTIR study reveals successful coating of PEG on the nanoparticles. DSC and XRD results demonstrated that drug changed its physical form in the formulation. The encapsulation efficiency was 63-74%. In vitro drug release was 57-75% for 48 hrs. Macrophage uptake of LMWH with pegylated nanoparticles was less compared to conventional PLGA nanoparticles. In vivo drug release was sustained for 48hrs; Optimized formulation exhibited good enhancement in pharmacokinetic parameters when compared to free drug solution. In vivo sustained release was also demonstrated with antithrombotic activity as well aPTT activity. Optimized formulation demonstrated significant stability, excellent antithrombotic activity in venous thrombosis rat model, improved aPTT levels when compared to free drug solution. CONCLUSION: An effective stealth LMWH nanoparticle formulation to treat venous thrombosis was successfully developed using w/o/w solvent evaporation technique.