Low molecular weight heparin downregulates tissue factor expression and activity by modulating growth factor receptor-mediated induction of nuclear factor-κB

Surface Modification with NGF-Loaded Chitosan/Heparin Nanoparticles for Improving Biocompatibility of Cardiovascular Stent

Late thrombosis and restenosis remain major challenges to the safety of drug-eluting stents. Biofunctional modification to endow the surface with selective anticoagulation and promote endothelium regeneration has become a hotpot recently. In this study, chitosan and heparin were found to form three-dimensional nanoparticles by spontaneous electrostatic interaction. Based on the specific binding properties between heparin and nerve growth factor (NGF), a new type of NGF-loaded heparin/chitosan nanoparticles was constructed for surface modification. The results of material characterization show that the nanoparticles are successfully immobilized on the surface of the material. In vitro blood compatibility and endothelial cell compatibility assay showed that the modified surface could selectively inhibit platelet adhesion and smooth muscle cell overproliferation, while accelerating endothelialization via promoting endothelial cell proliferation and enhancing endothelial progenitor cell mobilization.

Pharmacological and clinical application of heparin progress: An essential drug for modern medicine

Heparin is the earliest and most widely used anticoagulant and antithrombotic drug that is still used in a variety of clinical indications. Since it was discovered in 1916, after more than a century of repeated exploration, heparin has not been replaced by other drugs, but a great progress has been made in its basic research and clinical application. Besides anticoagulant and antithrombotic effects, heparin also has antitumor, anti-inflammatory, antiviral, and other pharmacological activities. It is widely used clinically in cardiovascular and cerebrovascular diseases, lung diseases, kidney diseases, cancer, etc., as the first anticoagulant medicine in COVID-19 exerts anticoagulant, anti-inflammatory and antiviral effects. At the same time, however, it also leads to a lot of adverse reactions, such as bleeding, thrombocytopenia, elevated transaminase, allergic reactions, and others. This article comprehensively reviews the modern research progress of heparin compounds; discusses the structure, preparation, and adverse reactions of heparin; emphasizes the pharmacological activity and clinical application of heparin; reveals the possible mechanism of the therapeutic effect of heparin in related clinical applications; provides evidence support for the clinical application of heparin; and hints on the significance of exploring the wider application fields of heparin.

The Anticoagulant and Nonanticoagulant Properties of Heparin

Heparins represent one of the most frequently used pharmacotherapeutics. Discovered around 1926, routine clinical anticoagulant use of heparin was initiated only after the publication of several seminal papers in the early 1970s by the group of Kakkar. It was shown that heparin prevents venous thromboembolism and mortality from pulmonary embolism in patients after surgery. With the subsequent development of low-molecular-weight heparins and synthetic heparin derivatives, a family of related drugs was created that continues to prove its clinical value in thromboprophylaxis and in prevention of clotting in extracorporeal devices. Fundamental and applied research has revealed a complex pharmacodynamic profile of heparins that goes beyond its anticoagulant use. Recognition of the complex multifaceted beneficial effects of heparin underscores its therapeutic potential in various clinical situations. In this review we focus on the anticoagulant and nonanticoagulant activities of heparin and, where possible, discuss the underlying molecular mechanisms that explain the diversity of heparin's biological actions.

Extrahepatic Portal Venous Obstruction With Hepatic Enzyme Elevation Resembling Hepatitis in Patients With Cancer

BACKGROUND/AIM

Chemotherapy is often halted due to abnormal liver function resembling hepatitis. But the cause can be extrahepatic portal venous obstruction (EHPVO) with hepatic enzyme elevation rather than being an adverse effect of chemotherapy. We investigated EHPVO with hepatic enzyme elevation in patients with cancer.

PATIENTS AND METHODS

Data of these hospitalized patients with solid tumors between January 2013 and September 2017 were collected. The criteria for study inclusion were: (i) Extrahepatic malignancy; (ii) computed tomographic scans showing a tumor with external compression of the extrahepatic portal vein; and (iii) serum aminotransferase (AST) or alanine transaminase (ALT) level three times above the normal value.

RESULTS

Thirteen out of 377 (3%) patients developed EHPVO with hepatic enzyme elevation, as demonstrated from computed tomographic scan. Four cases (31%) also had vascular thrombosis (three portal vein and one inferior vena cava). Serum AST increased from 34±11 to 169±94 U/l. ALT increased from 9±38 to 177±104 U/l. There was no relationship of EHPVO with viral markers and cirrhosis. Six cases received chemotherapy with liver function improvement.

CONCLUSION

EHPVO occurred in patients with metastatic cancer, leading to hepatic enzyme elevation resembling hepatitis without hepatitis risk factors and cirrhosis. Before withholding chemotherapy due to hepatic enzyme elevation, the possibility of EHPVO should firstly be excluded.

Immobilization of Fibronectin-Loaded Polyelectrolyte Nanoparticles on Cardiovascular Material Surface to Improve the Biocompatibility

Vascular stent interventional therapy is the main method for clinical treatment of coronary artery diseases. However, due to the insufficient biocompatibility of cardiovascular materials, the implantation of stents often leads to serious adverse cardiac events. Surface biofunctional modification to improve the biocompatibility of vascular stents has been the focus of current research. In this study, based on the structure and function of extracellular matrix on vascular injury healing, a novel fibronectin-loaded poly-l-lysine/heparin nanoparticles was constructed for stent surface modification. In vitro blood compatibility evaluation results showed that the nanoparticles-modified surface could effectively reduce platelet adhesion and activation. In vitro cellular compatibility evaluation results indicated that the nanocoating may provide adequate efficacy in promoting the adhesion and proliferation of endothelial cells and thereby accelerate endothelialization. This study provides a new approach for the surface biological function modification of vascular stents.

Thrombogenic Risk Induced by Intravascular Mesenchymal Stem Cell Therapy: Current Status and Future Perspectives

Mesenchymal stem cells (MSCs) are currently studied and used in numerous clinical trials. Nevertheless, some concerns have been raised regarding the safety of these infusions and the thrombogenic risk they induce. MSCs express procoagulant activity (PCA) linked to the expression of tissue factor (TF) that, when in contact with blood, initiates coagulation. Some even describe a dual activation of both the coagulation and the complement pathway, called Instant Blood-Mediated Inflammatory Reaction (IBMIR), explaining the disappointing results and low engraftment rates in clinical trials. However, nowadays, different approaches to modulate the PCA of MSCs and thus control the thrombogenic risk after cell infusion are being studied. This review summarizes both in vitro and in vivo studies on the PCA of MSC of various origins. It further emphasizes the crucial role of TF linked to the PCA of MSCs. Furthermore, optimization of MSC therapy protocols using different methods to control the PCA of MSCs are described.

Mesenchymal Stem Cells in the Adult Human Liver: Hype or Hope?

Chronic liver diseases constitute a significant economic, social, and biomedical burden. Among commonly adopted approaches, only organ transplantation can radically help patients with end-stage liver pathologies. Cell therapy with hepatocytes as a treatment for chronic liver disease has demonstrated promising results. However, quality human hepatocytes are in short supply. Stem/progenitor cells capable of differentiating into functionally active hepatocytes provide an attractive alternative approach to cell therapy for liver diseases, as well as to liver-tissue engineering, drug screening, and basic research. The application of methods generally used to isolate mesenchymal stem cells (MSCs) and maintain them in culture to human liver tissue provides cells, designated here as liver MSCs. They have much in common with MSCs from other tissues, but differ in two aspects-expression of a range of hepatocyte-specific genes and, possibly, inherent commitment to hepatogenic differentiation. The aim of this review is to analyze data regarding liver MSCs, probably another type of liver stem/progenitor cells different from hepatic stellate cells or so-called hepatic progenitor cells. The review presents an analysis of the phenotypic characteristics of liver MSCs, their differentiation and therapeutic potential, methods for isolating these cells from human liver, and discusses issues of their origin and heterogeneity. Human liver MSCs are a fascinating object of fundamental research with a potential for important practical applications.

Clinical Protocol to Prevent Thrombogenic Effect of Liver-Derived Mesenchymal Cells for Cell-Based Therapies

The efficacy of mesenchymal stem cell infusion is currently tested in numerous clinical trials. However, therapy-induced thrombotic consequences have been reported in several patients. The aim of this study was to optimize protocols for heterologous human adult liver-derived progenitor cell (HHALPC) infusion, in order to eliminate acute thrombogenesis in liver-based metabolic or acute decompensated cirrhotic (ADC) patients. In rats, thrombotic effects were absent when HHALPCs were infused at low cell dose (5 × 10⁶ cells/kg), or at high cell dose (5 × 10⁷ cells/kg) when combined with anticoagulants. When HHALPCs were exposed to human blood in a whole blood perfusion assay, blocking of the tissue factor (TF) coagulation pathway suppressed fibrin generation and platelet activation. In a Chandler tubing loop model, HHALPCs induced less explosive activation of coagulation with blood from ADC patients, when compared to blood from healthy controls, without alterations in coagulation factor levels other than fibrinogen. These studies confirm a link between TF and thrombogenesis, when TF-expressing cells are exposed to human blood. This phenomenon however, could be controlled using either a low, or a high cell dose combined with anticoagulants. In clinical practice, this points to the suitability of a low HHALPC dose infusion to cirrhotic patients, provided that platelet and fibrinogen levels are monitored.

Low molecular weight heparin and direct oral anticoagulants influence tumour formation, growth, invasion and vascularisation by separate mechanisms

The bidirectional association between coagulation and cancer has been established. However, anticoagulant therapies have been reported to have beneficial outcomes by influencing the vascularisation of the tumours. In this study the influence of a set of anticoagulants on tumour formation, invasion and vascularisation was examined. WM-266-4 melanoma and AsPC-1 pancreatic cancer cell lines were treated with LMWH (Tinzaparin and Dalteparin), and DOAC (Apixaban and Rivaroxaban) and the rate of tumour formation, growth and invasion were measured in vitro. In addition, the influence of these anticoagulants on vascularisation was examined using the chorioallantoic membrane assay (CAM) model and compared to the outcome of treatment with Bevacizumab. Using this model the influence of pharmacological concentrations of the anticoagulant on the growth, invasion and vascularisation of tumours derived from WM-266-4 and AsPC-1 cells was also measured in vivo. Tinzaparin and Daltepain reduced tumour formation and invasion by the cell lines in vitro, but with dissimilar potencies. In addition, treatment of CAM with LMWH reduced the local vascular density beyond that achievable with Bevacizumab, particularly suppressing the formation of larger-diameter blood vessels. In contrast, treatment with DOAC was largely ineffective. Treatment of CAM-implanted tumours with LMWH also reduced tumour vascularisation, while treatment of tumours with Apixaban reduced tumour growth in vivo. In conclusion, LMWH and DOAC appear to have anti-cancer properties that are exerted through different mechanisms.

The intertwined fates of inflammation and coagulation in glioma

Inflammation and coagulation are two intertwined pathways with evolutionary ties being traced back to the hemocyte, a single cell type in invertebrates that has functions in both the inflammatory and coagulation pathways. These systems have functioned together throughout evolution to provide a solid defence against infection, damaged cells and irritants. While these systems work in harmony the majority of the time, they can also become dysregulated or corrupted by tumours, enhancing tumour proliferation, invasion, dissemination and survival. This review aims to give a brief overview of how these systems work in harmony and how dysregulation of these systems aids in the development and progression of cancer, using glioma as an example.

Anlotinib inhibits angiogenesis via suppressing the activation of VEGFR2, PDGFRβ and FGFR1

Tumor cells recruit vascular endothelial cells and circulating endothelial progenitor cells to form new vessels to support their own growth and metastasis. VEGF, PDGF-BB and FGF-2 are three major pro-angiogenic factors and applied to promote angiogenesis. In this research, we demonstrated that anlotinib, a potent multi-tyrosine kinases inhibitor (TKI), showed a significant inhibitory effect on VEGF/PDGF-BB/FGF-2-induced angiogenesis in vitro and in vivo. Wound healing assay, chamber directional migration assay and tube formation assay indicated that anlotinib inhibited VEGF/PDGF-BB/FGF-2-induced cell migration and formation of capillary-like tubes in endothelial cells. Furthermore, anlotinib suppressed blood vessels sprout and microvessel density in rat aortic ring assay and chicken chorioallantoic membrane (CAM) assay. Importantly, according to our study, the anti-angiogenic effect of anlotinib is superior to sunitinib, sorafenib and nintedanib, which are three main anti-angiogenesis drugs in clinic. Mechanistically, anlotinib inhibits the activation of VEGFR2, PDGFRβ and FGFR1 as well their common downstream ERK signaling. Therefore, anlotinib is a potential agent to inhibit angiogenesis and be applied to tumor therapy.

More than an anticoagulant: Do heparins have direct anti-inflammatory effects?

The heparins, well-known for their anticoagulant properties, may also have anti-inflammatory effects that could contribute to their effectiveness in the treatment of venous thromboembolism and other vascular diseases. This review focuses on the inflammatory pathophysiology that underlies the development of thrombosis and the putative effects of heparin on these pathways. We present evidence supporting the use of heparin for other indications, including autoimmune disease, malignancy, and disseminated intravascular coagulation. These considerations highlight the need for further research to elucidate the mechanisms of the possible pleiotropic effects of the heparins, with a view to advancing treatments based upon heparin derivatives.

Surface Modification with ECM-Inspired SDF-1α/Laminin-Loaded Nanocoating for Vascular Wound Healing

Surface biomimetic modification with extra-cellular matrix (ECM)-derived biomolecules is an emerging potential method of accelerating the healing of vascular stent lesions. However, insufficient capacity of the constructed biofunctional layer in maintaining its long-term efficiency and preventing thrombus and neointimal hyperplasia continue to be major limitations in clinical application. On the basis of the structure and function of ECM, in this study, we constructed a novel stromal cell-derived factor-1α (SDF-1α)/laminin-loaded nanocoating on the 316L stainless steel (SS) surface to provide improved function in modulation of vascular remodeling. The modified surface was found to control delivery of biomolecules and exhibit promising potential to provide stage-adjusted treatment after injury. An in vitro biocompatibility study suggested that the constructed layer may effectively prevent thrombosis formation by inhibiting platelet adhesion and activation, while accelerating endothelium regeneration by inducing endothelial cell (EC) migration and endothelial progenitor cell (EPC) aggregation. An in vivo animal test further demonstrated that the nanocoating may prevent thrombus and neointimal hyperplasia after implantation for 3 months. Therefore, the ECM-inspired nanocoating described in this study is a promising novel approach for vascular stent surface modification.

Dangerous liaisons: complement, coagulation, and kallikrein/kinin cross-talk act as a linchpin in the events leading to thromboinflammation

Innate immunity is fundamental to our defense against microorganisms. Physiologically, the intravascular innate immune system acts as a purging system that identifies and removes foreign substances leading to thromboinflammatory responses, tissue remodeling, and repair. It is also a key contributor to the adverse effects observed in many diseases and therapies involving biomaterials and therapeutic cells/organs. The intravascular innate immune system consists of the cascade systems of the blood (the complement, contact, coagulation, and fibrinolytic systems), the blood cells (polymorphonuclear cells, monocytes, platelets), and the endothelial cell lining of the vessels. Activation of the intravascular innate immune system in vivo leads to thromboinflammation that can be activated by several of the system's pathways and that initiates repair after tissue damage and leads to adverse reactions in several disorders and treatment modalities. In this review, we summarize the current knowledge in the field and discuss the obstacles that exist in order to study the cross-talk between the components of the intravascular innate immune system. These include the use of purified in vitro systems, animal models and various types of anticoagulants. In order to avoid some of these obstacles we have developed specialized human whole blood models that allow investigation of the cross-talk between the various cascade systems and the blood cells. We in particular stress that platelets are involved in these interactions and that the lectin pathway of the complement system is an emerging part of innate immunity that interacts with the contact/coagulation system. Understanding the resulting thromboinflammation will allow development of new therapeutic modalities.

Surface biomimetic modification with laminin-loaded heparin/poly-l-lysine nanoparticles for improving the biocompatibility

Late thrombus and restenosis caused by delayed endothelialization and insufficient biocompatibility of polymer coating continue to be the greatest limitations of drug-eluting stents. In this study, based on the specific structure of vascular basement membrane, a novel biomimetic nano-coating was constructed by incorporating laminin into electrostatic-assembled heparin/poly-l-lysine nanoparticles. Alteration of heparin and poly-l-lysine concentration ratio in a certain range has no significantly influence nanoparticle size, uniformity and stability, but may affect the chemical property and subsequently the binding efficiency to dopamine-coated titanium surface. By use of this feature, four different nanoparticles were synthesized and immobilized on titanium surface for creating gradient nanoparticle binding density. According to in vitro biocompatibility evaluation, the nanoparticle modified surfaces were found to effectively block coagulation pathway and reduce thrombosis formation. Moreover, NP10L and NP15L modified surface with relatively low heparin exposing density (4.9 to 7.1μg/cm2) showed beneficial effect in selective promoting EPCs and ECs proliferation, as well as stimulating cell migration and NO synthesis.

The Role of Pulmonary Veins in Cancer Progression from a Computed Tomography Viewpoint

Background. We studied the role of pulmonary veins in cancer progression using computed tomography (CT) scans. Methods. We obtained data from 260 patients with pulmonary vein obstruction syndrome (PVOS). We used CT scans to investigate pulmonary lesions in relation to pulmonary veins. We divided the lesions into central and peripheral lesions by their anatomical location: in the lung parenchymal tissue or pulmonary vein; in the superior or inferior pulmonary vein; and by unilateral or bilateral presence in the lungs. Results. Of the 260 PVOS patients, 226 (87%) had central lesions, 231 (89%) had peripheral lesions, and 190 (75%) had mixed central and peripheral lesions. Among the 226 central lesions, 93% had lesions within the superior pulmonary vein, either bilaterally or unilaterally. Among the 231 peripheral lesions, 65% involved bilateral lungs, 70% involved lesions within the inferior pulmonary veins, and 23% had obvious metastatic extensions into the left atrium. All patients exhibited nodules within their pulmonary veins. The predeath status included respiratory failure (40%) and loss of consciousness (60%). Conclusion. CT scans play an important role in following tumor progression within pulmonary veins. Besides respiratory distress, PVOS cancer cells entering centrally can result in cardiac and cerebral events and loss of consciousness or can metastasize peripherally from the pulmonary veins to the lungs.

Analysis of the potential of cancer cell lines to release tissue factor-containing microvesicles: correlation with tissue factor and PAR2 expression

BACKGROUND

Despite the association of cancer-derived circulating tissue factor (TF)-containing microvesicles and hypercoagulable state, correlations with the incidence of thrombosis remain unclear.

METHODS

In this study the upregulation of TF release upon activation of various cancer cell lines, and the correlation with TF and PAR2 expression and/or activity was examined. Microvesicle release was induced by PAR2 activation in seventeen cell lines and released microvesicle density, microvesicle-associated TF activity, and phoshpatidylserine-mediated activity were measured. The time-course for TF release was monitored over 90 min in each cell line. In addition, TF mRNA expression, cellular TF protein and cell-surface TF activities were quantified. Moreover, the relative expression of PAR2 mRNA and cellular protein were analysed. Any correlations between the above parameters were examined by determining the Pearson's correlation coefficients.

RESULTS

TF release as microvesicles peaked between 30-60 min post-activation in the majority of cell lines tested. The magnitude of the maximal TF release positively correlated with TF mRNA (c = 0.717; p < 0.001) and PAR2 mRNA (c = 0.770; p < 0.001) expressions while the percentage increase correlated with PAR2 mRNA (c = 0.601; p = 0.011) and protein (c = 0.714; p < 0.001). There was only a weak correlation between resting TF release, and microvesicle release. However, TF release in resting cells did not significantly correlate with any of the parameters examined. Furthermore, TF mRNA expression correlated with PAR2 mRNA expression (c = 0.745; p < 0.001).

DISCUSSION AND CONCLUSIONS

In conclusion, our data suggest that TF and PAR2 mRNA, and PAR2 protein are better indicators of the ability of cancer cells to release TF and may constitute more accurate predictors of risk of thrombosis.

Heparin Decreases in Tumor Necrosis Factor α (TNFα)-induced Endothelial Stress Responses Require Transmembrane Protein 184A and Induction of Dual Specificity Phosphatase 1

Despite the large number of heparin and heparan sulfate binding proteins, the molecular mechanism(s) by which heparin alters vascular cell physiology is not well understood. Studies with vascular smooth muscle cells (VSMCs) indicate a role for induction of dual specificity phosphatase 1 (DUSP1) that decreases ERK activity and results in decreased cell proliferation, which depends on specific heparin binding. The hypothesis that unfractionated heparin functions to decrease inflammatory signal transduction in endothelial cells (ECs) through heparin-induced expression of DUSP1 was tested. In addition, the expectation that the heparin response includes a decrease in cytokine-induced cytoskeletal changes was examined. Heparin pretreatment of ECs resulted in decreased TNFα-induced JNK and p38 activity and downstream target phosphorylation, as identified through Western blotting and immunofluorescence microscopy. Through knockdown strategies, the importance of heparin-induced DUSP1 expression in these effects was confirmed. Quantitative fluorescence microscopy indicated that heparin treatment of ECs reduced TNFα-induced increases in stress fibers. Monoclonal antibodies that mimic heparin-induced changes in VSMCs were employed to support the hypothesis that heparin was functioning through interactions with a receptor. Knockdown of transmembrane protein 184A (TMEM184A) confirmed its involvement in heparin-induced signaling as seen in VSMCs. Therefore, TMEM184A functions as a heparin receptor and mediates anti-inflammatory responses of ECs involving decreased JNK and p38 activity.

Bone Marrow-Derived Mesenchymal Stem Cells Have Innate Procoagulant Activity and Cause Microvascular Obstruction Following Intracoronary Delivery: Amelioration by Antithrombin Therapy

Mesenchymal stem cells (MSCs) are currently under investigation as tools to preserve cardiac structure and function following acute myocardial infarction (AMI). However, concerns have emerged regarding safety of acute intracoronary (IC) MSC delivery. This study aimed to characterize innate prothrombotic activity of MSC and identify means of its mitigation toward safe and efficacious therapeutic IC MSC delivery post-AMI. Expression of the initiator of the coagulation cascade tissue factor (TF) on MSC was detected and quantified by immunofluorescence, FACS, and immunoblotting. MSC-derived TF antigen was catalytically active and capable of supporting thrombin generation in vitro. Addition of MSCs to whole citrated blood enhanced platelet thrombus deposition on collagen at arterial shear, an effect abolished by heparin coadministration. In a porcine AMI model, IC infusion of 25 × 10(6) MSC during reperfusion was associated with a decrease in coronary flow reserve but not when coadministered with an antithrombin agent (heparin). Heparin reduced MSC-associated thrombosis incorporating platelets and VWF within the microvasculature. Heparin-assisted therapeutic MSC delivery also reduced apoptosis in the infarct border zone at 24 hours, significantly improved infarct size, left ventricular (LV) ejection fraction, LV volumes, wall motion, and attenuated histologic evidence of scar formation at 6 weeks post-AMI. Heparin alone or heparin-assisted fibroblast control cell delivery had no such effect. Procoagulant TF activity of therapeutic MSCs is associated with reductions in myocardial perfusion when delivered IC may be successfully managed by heparin coadministration. This study highlights an important mechanistic insight into safety concerns associated with therapeutic IC MSC delivery for AMI.

Characterization of physical properties of tissue factor-containing microvesicles and a comparison of ultracentrifuge-based recovery procedures

Microvesicles were isolated from the conditioned media of 3 cell lines (MDA-MB-231, AsPC-1 and A375) by ultracentrifugation at a range of relative centrifugal forces, and the tissue factor (TF) protein and activity, microvesicle number, size distribution and relative density compared. Also, by expressing TF-tGFP in cells and isolating the microvesicles, the relative density of TF-containing microvesicles was established. Nanoparticle tracking analysis (NTA) indicated that the larger-diameter microvesicles (>200 nm) were primarily sedimented at 100,000g and possessed TF-dependent thrombin and factor Xa generation potential, while in the absence of factor VII, all microvesicles possessed some thrombin generation capacity. Immuno-precipitation of TF-containing microvesicles followed by NTA also indicated the range of these microvesicles to be 200–400 nm. Analysis of the microvesicles by gradient density centrifugation showed that lower-density (<1.1 g/ml) microvesicles were mainly present in the samples recovered at 100,000g and were associated with TF antigen and activity. Analysis of these fractions by NTA confirmed that these fractions were principally composed of the larger-diameter microvesicles. Similar analysis of microvesicles from healthy or patient plasma supported those obtained from conditioned media indicating that TF activity was mainly associated with lower-density microvesicles. Furthermore, centrifugation of healthy plasma, supplemented with TF-tGFP-containing microvesicles, resulted in 67% retrieval of the fluorescent microvesicles at 100,000g, but only 26% could be recovered at 20,000g. Pre-centrifugation of conditioned media or plasma at 10,000g improved the speed and yield of recovered TF-containing microvesicles by subsequent centrifugation at either 20,000g or 100,000g. In conclusion, TF appears to be associated with low-density (1.03–1.08 g/ml), larger-diameter (200–350 nm) microvesicles.

Surface modification with dopamine and heparin/poly-L-lysine nanoparticles provides a favorable release behavior for the healing of vascular stent lesions

Surface biofunctional modification of coronary artery stents to prevent thrombosis and restenosis formation, as well as accelerate endothelialization, has become a new hot spot. However, bioactive coatings on implants are not yet sufficiently developed for long-term activity, as they quickly lose efficiency in vivo and finally fail. On the basis of a novel time-ordered concept of biofunctionality for vascular stents, heparin/poly l-lysine nanoparticle (NP) was developed and immobilized on a polydopamine-coated titanium surface, with the aim of regulating and maintaining the intravascular biological response within the normal range after biomaterial implantation. An in vitro dynamic release model was established to mimic the blood flow condition in vivo with three phases: (1) An early phase (1-7 days) with release of predominantly anticoagulant and anti-inflammatory substances and to a minor degree antiproliferative effects against smooth muscle cells (SMCs); (2) this is followed by a phase (7-14 days) of supported endothelial cell (ECs) proliferation and suppressed SMC proliferation with persisting high antithrombogenicity and anti-inflammatory properties of the surface. (3) Finally, a stable stage (14-28 days) with adequate biomolecules on the surface that maintain hemocompatibility and anti inflammation as well as inhibit SMCs proliferation and promote ECs growth. In vivo animal tests further confirmed that the NP-modified surface provides a favorable release behavior to apply a stage-adjusted remedy. We suggested that these observations provide important guidance and potential means for reasonable and suitable platform construction on a stent surface.

Fibroblast growth factor receptor 3 interacts with and activates TGFβ-activated kinase 1 tyrosine phosphorylation and NFκB signaling in multiple myeloma and bladder cancer

Cancer is a major public health problem worldwide. In the United States alone, 1 in 4 deaths is due to cancer and for 2013 a total of 1,660,290 new cancer cases and 580,350 cancer-related deaths are projected. Comprehensive profiling of multiple cancer genomes has revealed a highly complex genetic landscape in which a large number of altered genes, varying from tumor to tumor, impact core biological pathways and processes. This has implications for therapeutic targeting of signaling networks in the development of treatments for specific cancers. The NFκB transcription factor is constitutively active in a number of hematologic and solid tumors, and many signaling pathways implicated in cancer are likely connected to NFκB activation. A critical mediator of NFκB activity is TGFβ-activated kinase 1 (TAK1). Here, we identify TAK1 as a novel interacting protein and target of fibroblast growth factor receptor 3 (FGFR3) tyrosine kinase activity. We further demonstrate that activating mutations in FGFR3 associated with both multiple myeloma and bladder cancer can modulate expression of genes that regulate NFκB signaling, and promote both NFκB transcriptional activity and cell adhesion in a manner dependent on TAK1 expression in both cancer cell types. Our findings suggest TAK1 as a potential therapeutic target for FGFR3-associated cancers, and other malignancies in which TAK1 contributes to constitutive NFκB activation.

Microparticle-associated tissue factor is recycled by endothelial cells resulting in enhanced surface tissue factor activity

In this study the uptake of tissue factor (TF)-positive microparticles by endothelial cells and the recycling of the TF component were examined. Human dermal blood endothelial cells (HDBEC) were incubated with microparticles derived from cancer cell lines for up to 6 hours. Measurement of HDBEC cell surface TF antigen revealed two distinct peaks at 30 and 180-240 minutes post-incubation with TF-positive, but not TF-deficient microparticles. However, only the second peak was concurrent with high TF activity as determined by a chromogenic thrombin-generation assay. Annexin V-labelling of HDBEC showed phosphatidylserine exposure following 90 minutes incubation with microparticles, which explains the high TF activity associated with the second antigen peak. Analysis of TF mRNA levels revealed no de novo expression of TF mRNA in response to microparticles, and pre-incubation of cells with cycloheximide did not prevent the appearance of TF. However, blocking endocytosis with a dynamin inhibitor prolonged the disappearance and prevented the reappearance of TF antigen on the cell surface. Incubation of HDBEC with microparticles containing TF-GFP revealed the early co-localisation of TF with Rab4 and Rab5, followed by co-localisation with the late endosomal/trans-Golgi network marker Rab9, and the recycling endosome marker Rab11. siRNA-mediated suppression of Rab11 reduced the reappearance of TF on the cell surface. These data suggest a mechanism by which TF-containing microparticles are internalised by endothelial cells and the TF moiety recycled to the cell surface. Together with the exposure of phosphatidylserine, this is capable of inducing a substantial increase in the procoagulant potential of the surface of endothelial cells.

A novel coagulation assay incorporating adherent endothelial cells in thromboelastometry

Following vascular injury or activation, endothelial cells (ECs) participate in the modulation of haemostasis and fibrinolysis. Viscoelastic tests (VETs) are a potent bedside monitoring tool that reports haemostatic parameters in real time. However, VETs neglect the influence of the surrounding endothelium. Our aim was therefore to establish an assay that incorporates ECs in a whole blood VET and to assess the impact of ECs on coagulation parameters. Outgrowth endothelial cells (OECs) and human umbilical vein endothelial cells (HUVECs) were seeded onto microbeads to create transferable EC-microcarriers. Microbeads were then added to citrated whole blood in the measurement cup of a thromboelastometry device (ROTEM). After the addition of CaCl2 (star-TEM®) to the blood sample (NATEM assay), standard ROTEM parameters were analysed. Scanning electron microscopy (SEM) was carried out to visualise the interactions of the beads, whole blood components and the ROTEM pin after clotting. SEM showed that the added microbeads were effectively incorporated into the final blood clot. In the presence of activated ECs, the clotting time (CT) of the blood was shortened fourfold compared to that in uncoated control beads. A significant reduction in CT was also observed in the presence of unstimulated ECs. Interestingly, CT was also reduced by the addition of purified EC culture supernatant. CT shortening was prevented by incubating the supernatant with an inhibiting antibody against tissue factor (TF). Our findings demonstrate that ECs can be incorporated into a ROTEM assay via coated microbeads, and whole blood clotting initiation is accelerated by non-activated and activated ECs.

Evaluation of the blood compatibility of materials, cells, and tissues: basic concepts, test models, and practical guidelines

Medicine today uses a wide range of biomaterials, most of which make contact with blood permanently or transiently upon implantation. Contact between blood and nonbiological materials or cells or tissue of nonhematologic origin initiates activation of the cascade systems (complement, contact activation/coagulation) of the blood, which induces platelet and leukocyte activation. Although substantial progress regarding biocompatibility has been made, many materials and medical treatment procedures are still associated with severe side effects. Therefore, there is a great need for adequate models and guidelines for evaluating the blood compatibility of biomaterials. Due to the substantial amount of cross talk between the different cascade systems and cell populations in the blood, it is advisable to use an intact system for evaluation. Here, we describe three such in vitro models for the evaluation of the biocompatibility of materials and therapeutic cells and tissues. The use of different anticoagulants and specific inhibitors in order to be able to dissect interactions between the different cascade systems and cells of the blood is discussed. In addition, we describe two clinically relevant medical treatment modalities, the integration of titanium implants and transplantation of islets of Langerhans to patients with type 1 diabetes, whose mechanisms of action we have addressed using these in vitro models.

p38α phosphorylates serine 258 within the cytoplasmic domain of tissue factor and prevents its incorporation into cell-derived microparticles

We previously showed that the phosphorylation of Ser253 within the cytoplasmic domain of human tissue factor (TF) initiates the incorporation and release of this protein into cell-derived microparticles. Furthermore, subsequent phosphorylation of Ser258 terminates this process. However, the identity of the kinase responsible for the phosphorylation of Ser258 and mode of action of this enzyme remain unknown. In this study, p38α was identified as the proline-directed kinase capable of phosphorylating Ser258 specifically, and without any detectable activity towards Ser253. Furthermore, using synthetic peptides, it was shown that the Km for the reaction decreased by approximately 10 fold on substitution of Ser253 with phospho-Ser253. Either inhibition of p38 using SB202190 or knockdown of p38α expression in coronary artery endothelial cells overexpressing wild-type TF, resulted in decreased phosphorylation of Ser258, following activation of cells with PAR2-agonist peptide (PAR2-AP). In agreement with our previous data, inhibition of phosphorylation of this residue maintained the release of TF. Activation of PAR2 in cells transfected to overexpress TF, resulted in two separate peaks of p38 activity at approximately 40 and 120 min post-activation. Furthermore, overexpression of Ala253-substituted TF enhanced the second p38 activation peak. However, the second peak was absent in cells devoid of TF or in cells overexpressing the Asp253-substituted TF. Our data clearly identifies p38α as a kinase capable of phosphorylating Ser258 within the cytoplasmic domain of TF. Moreover, it appears that the presence of TF within the cells regulates the late activation of p38 and consequently the termination of TF release into microparticles.

Enhanced binding of tissue factor-microparticles to collagen-IV and fibronectin leads to increased tissue factor activity in vitro

The role of tissue factor (TF)-containing microparticles in clot propagation has been established, but the ability of circulating microparticles to initiate coagulation has been disputed. However, TF-bearing microparticles, particularly endothelial-microparticles generated during disease, may interact with extracellular matrices which in turn can localise circulating TF to sites of injury. In order to examine this hypothesis in vitro , microparticles were isolated from human coronary artery endothelial cells transfected to overexpress TF, tumour-necrosis factor (TNF) α-treated cells or non-transfected cells lacking TF. The ability of microparticles to bind collagen-IV, fibronectin and fibrin was examined under static conditions and arterial shear rates (650 s⁻¹), and also in the presence of inhibitory antibodies against β1-, β3-, α3- and αv-integrins or an anti-TF antibody. TF-microparticles showed increases of up to 43% and 24% in adherence to collagen-IV and fibronectin, respectively, compared to control microparticles under shear flow. Furthermore, TF-containing microparticles, but not the transfected parent cells had increased levels of β1-integrin compared to TF-deficient microparticles. Pre-incubation of microparticles with a β1-integrin-blocking antibody counteracted the additional adhesion of TF-microparticles compared to control microparticles. Finally, adherence of TF microparticles to collagen-IV or fibronectin resulted in increased TF activity by concentrating TF onto the surface. In conclusion, the presence of TF within microparticles enhances the interactions of endothelial cell-derived microparticles with extracellular matrices in an integrin-dependent manner. Accumulation and localisation of these microparticles in turn results in the enhancement of TF activity. This may be an innate mechanism by which TF-bearing microparticles induce coagulation upon vascular injury.

Enoxaparin prevents portal vein thrombosis and liver decompensation in patients with advanced cirrhosis

BACKGROUND & AIMS

We performed a randomized controlled trial to evaluate the safety and efficacy of enoxaparin, a low-molecular-weight heparin, in preventing portal vein thrombosis (PVT) in patients with advanced cirrhosis.

METHODS

In a nonblinded, single-center study, 70 outpatients with cirrhosis (Child-Pugh classes B7-C10) with demonstrated patent portal veins and without hepatocellular carcinoma were assigned randomly to groups that were given enoxaparin (4000 IU/day, subcutaneously for 48 weeks; n = 34) or no treatment (controls, n = 36). Ultrasonography (every 3 months) and computed tomography (every 6 months) were performed to check the portal vein axis. The primary outcome was prevention of PVT. Radiologists and hepatologists that assessed outcomes were blinded to group assignments. Analysis was by intention to treat.

RESULTS

At 48 weeks, none of the patients in the enoxaparin group had developed PVT, compared with 6 of 36 (16.6%) controls (P = .025). At 96 weeks, no patient developed PVT in the enoxaparin group, compared with 10 of 36 (27.7%) controls (P = .001). At the end of the follow-up period, 8.8% of patients in the enoxaparin group and 27.7% of controls developed PVT (P = .048). The actuarial probability of PVT was lower in the enoxaparin group (P = .006). Liver decompensation was less frequent among patients given enoxaparin (11.7%) than controls (59.4%) (P < .0001); overall values were 38.2% vs 83.0%, respectively (P < .0001). The actuarial probability of liver decompensation was lower in the enoxaparin group (P < .0001). Eight patients in the enoxaparin group and 13 controls died. The actuarial probability of survival was higher in the enoxaparin group (P = .020). No relevant side effects or hemorrhagic events were reported.

CONCLUSIONS

In a small randomized controlled trial, a 12-month course of enoxaparin was safe and effective in preventing PVT in patients with cirrhosis and a Child-Pugh score of 7-10. Enoxaparin appeared to delay the occurrence of hepatic decompensation and to improve survival.