Low anticoagulant heparin targets multiple sites of inflammation, suppresses heparin-induced thrombocytopenia, and inhibits interaction of RAGE with its ligands

Site-specific thrombus formation: advancements in photothrombosis-on-a-chip technology

Thrombosis, characterized by blood clot formation within vessels, poses a significant medical challenge. Despite extensive research, the development of effective thrombosis therapies is hindered by substantial costs, lengthy development times, and high failure rates in medication commercialization. Conventional pre-clinical models often oversimplify cardiovascular disease, leading to a disparity between experimental results and human physiological responses. In response, we have engineered a photothrombosis-on-a-chip system. This microfluidic model integrates human endothelium, human whole blood, and blood flow dynamics and employs the photothrombotic method. It enables precise, site-specific thrombus induction through controlled laser irradiation, effectively mimicking both normal and thrombotic physiological conditions on a single chip. Additionally, the system allows for the fine-tuning of thrombus occlusion levels via laser parameter adjustments, offering a flexible thrombus model with varying degrees of obstruction. Additionally, the formation and progression of thrombosis noted on the chip closely resemble the thrombotic conditions observed in mice in previous studies. In the experiments, we perfused recalcified whole blood with Rose Bengal into an endothelialized microchannel and initiated photothrombosis using green laser irradiation. Various imaging methods verified the model's ability to precisely control thrombus formation and occlusion levels. The effectiveness of clinical drugs, including heparin and rt-PA, was assessed, confirming the chip's potential in drug screening applications. In summary, the photothrombosis-on-a-chip system significantly advances human thrombosis modeling. Its precise control over thrombus formation, flexibility in the thrombus severity levels, and capability to simulate dual physiological states on a single platform make it an invaluable tool for targeted drug testing, furthering the development of organ-on-a-chip drug screening techniques.

Exploring the therapeutic role of early heparin administration in ARDS management: a MIMIC-IV database analysis

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a severe respiratory condition characterized by a high mortality rate, the management of which relies on supportive care and a profound understanding of its pathophysiology. Heparin, with its anticoagulant and potential anti-inflammatory properties, offers a new therapeutic opportunity for the treatment of ARDS.

METHODS

In this retrospective cohort study, we examined the MIMIC-IV database for ARDS patients who received prophylactic heparin within the first 72 h of ICU admission. Employing propensity score matching and inverse probability weighting (IPW) analysis, we evaluated the impact of early heparin use on patient outcomes, focusing on mortality rates.

RESULTS

Patients who received prophylactic heparin had a significantly lower in-hospital mortality rate compared to those who did not (13.55% vs 17.93%, HR = 0.71, 95% CI: 0.54-0.93, P = 0.012). This result remained significant after propensity score matching (12.75% vs 17.93%, HR = 0.65, 95% CI 0.47-0.90, P = 0.010). Analysis using five different statistical models indicated that early use of heparin significantly reduced the in-hospital mortality rate, with HR = 0.669 (95% CI 0.487-0.919, P = 0.013) in the doubly robust model without balanced covariates; HR = 0.705 (95% CI 0.515-0.965, P = 0.029) with all covariates considered; HR = 0.660 (95% CI 0.491-0.888, P = 0.006) in the propensity score (IPW) model; HR = 0.650 (95% CI 0.470-0.900, P = 0.010) in the propensity score matching model; and HR = 0.706 (95% CI 0.536-0.930, P = 0.013) in the multivariate Cox regression model. Secondary outcomes indicated that heparin use was also associated with reduced mortality rates at 60 days, and 90 days.

CONCLUSION

This research highlights that early prophylactic administration of heparin may substantially lower mortality in ARDS patients. These findings underscore the potential of heparin as a key component in the management of ARDS, offering a new perspective and novel strategies for clinical treatment.

Therapeutic strategies in FcγIIA receptor-dependent thrombosis and thromboinflammation as seen in heparin-induced thrombocytopenia (HIT) and vaccine-induced immune thrombocytopenia and thrombosis (VITT)

INTRODUCTION

Fcγ-receptors (FcγR) are membrane receptors expressed on a variety of immune cells, specialized in recognition of the Fc part of immunoglobulin G (IgG) antibodies. FcγRIIA-dependent platelet activation in platelet factor 4 (PF4) antibody-related disorders have gained major attention, when these antibodies were identified as the cause of the adverse vaccination event termed vaccine-induced immune thrombocytopenia and thrombosis (VITT) during the COVID-19 vaccination campaign. With the recognition of anti-PF4 antibodies as cause for severe spontaneous and sometimes recurrent thromboses independent of vaccination, their clinical relevance extended far beyond heparin-induced thrombocytopenia (HIT) and VITT.

AREAS COVERED

Patients developing these disorders show life-threatening thromboses, and the outcome is highly dependent on effective treatment. This narrative literature review summarizes treatment options for HIT and VITT that are currently available for clinical application and provides the perspective toward new developments.

EXPERT OPINION

Nearly all these novel approaches are based on in vitro, preclinical observations, or case reports with only limited implementation in clinical practice. The therapeutic potential of these approaches still needs to be proven in larger cohort studies to ensure treatment efficacy and long-term patient safety.

Inflammation and coagulation abnormalities via the activation of the HMGB1‑RAGE/NF‑κB and F2/Rho pathways in lung injury induced by acute hypoxia

High‑altitude acute hypoxia is commonly associated with respiratory cardiovascular diseases. The inability to adapt to acute hypoxia may lead to cardiovascular dysfunction, lung injury and even death. Therefore, understanding the molecular basis of the adaptation to high‑altitude acute hypoxia may reveal novel therapeutic approaches with which to counteract the detrimental consequences of hypoxia. In the present study, a high‑altitude environment was simulated in a rat model in order to investigate the role of the high mobility group protein‑1 (HMGB1)/receptor for advanced glycation end products (RAGE)/NF‑κB and F2/Rho signaling pathways in lung injury induced by acute hypoxia. It was found that acute hypoxia caused inflammation through the HMGB1/RAGE/NF‑κB pathway and coagulation dysfunction through the F2/Rho pathway, both of which may be key processes in acute hypoxia‑induced lung injury. The present study provides new insight into the molecular basis of lung injury induced by acute hypoxia. The simultaneous activation of the HMGB1/RAGE/NF‑κB and F2/Rho signaling pathways plays a critical role in hypoxia‑induced inflammatory responses and coagulation abnormalities, and provides a theoretical basis for the development of potential therapeutic strategies.

Heparin, Low Molecular Weight Heparin, and Non-Anticoagulant Derivatives for the Treatment of Inflammatory Lung Disease

Unfractionated heparin has multiple pharmacological activities beyond anticoagulation. These anti-inflammatory, anti-microbial, and mucoactive activities are shared in part by low molecular weight and non-anticoagulant heparin derivatives. Anti-inflammatory activities include inhibition of chemokine activity and cytokine synthesis, inhibitory effects on the mechanisms of adhesion and diapedesis involved in neutrophil recruitment, inhibition of heparanase activity, inhibition of the proteases of the coagulation and complement cascades, inhibition of neutrophil elastase activity, neutralisation of toxic basic histones, and inhibition of HMGB1 activity. This review considers the potential for heparin and its derivatives to treat inflammatory lung disease, including COVID-19, ALI, ARDS, cystic fibrosis, asthma, and COPD via the inhaled route.

Pharmacology of Heparin and Related Drugs: An Update

Heparin has been used extensively as an antithrombotic and anticoagulant for close to 100 years. This anticoagulant activity is attributed mainly to the pentasaccharide sequence, which potentiates the inhibitory action of antithrombin, a major inhibitor of the coagulation cascade. More recently it has been elucidated that heparin exhibits anti-inflammatory effect via interference of the formation of neutrophil extracellular traps and this may also contribute to heparin's antithrombotic activity. This illustrates that heparin interacts with a broad range of biomolecules, exerting both anticoagulant and nonanticoagulant actions. Since our previous review, there has been an increased interest in these nonanticoagulant effects of heparin, with the beneficial role in patients infected with SARS2-coronavirus a highly topical example. This article provides an update on our previous review with more recent developments and observations made for these novel uses of heparin and an overview of the development status of heparin-based drugs. SIGNIFICANCE STATEMENT: This state-of-the-art review covers recent developments in the use of heparin and heparin-like materials as anticoagulant, now including immunothrombosis observations, and as nonanticoagulant including a role in the treatment of SARS-coronavirus and inflammatory conditions.

Heparan sulfates and heparan sulfate binding proteins in sepsis

Heparan sulfates (HSs) are the main components in the glycocalyx which covers endothelial cells and modulates vascular homeostasis through interactions with multiple Heparan sulfate binding proteins (HSBPs). During sepsis, heparanase increases and induces HS shedding. The process causes glycocalyx degradation, exacerbating inflammation and coagulation in sepsis. The circulating heparan sulfate fragments may serve as a host defense system by neutralizing dysregulated Heparan sulfate binding proteins or pro-inflammatory molecules in certain circumstances. Understanding heparan sulfates and heparan sulfate binding proteins in health and sepsis is critical to decipher the dysregulated host response in sepsis and advance drug development. In this review, we will overview the current understanding of HS in glycocalyx under septic condition and the dysfunctional heparan sulfate binding proteins as potential drug targets, particularly, high mobility group box 1 (HMGB1) and histones. Moreover, several drug candidates based on heparan sulfates or related to heparan sulfates, such as heparanase inhibitors or heparin-binding protein (HBP), will be discussed regarding their recent advances. By applying chemical or chemoenzymatic approaches, the structure-function relationship between heparan sulfates and heparan sulfate binding proteins is recently revealed with structurally defined heparan sulfates. Such homogenous heparan sulfates may further facilitate the investigation of the role of heparan sulfates in sepsis and the development of carbohydrate-based therapy.

Relationship between severe acute respiratory syndrome coronavirus 2 and diabetes mellitus (review)

Infections caused by SARE-CoV-2 are complicated with the concurrent pathologies, to name hypertension, diabetes mellitus and cardiovascular diseases. High level of glucose in blood weakens the immunity and increase the SARS-CoV-2 replication. Diabetes mellitus aggravates the COVID-19 outcome. The intrusion of SARS-CoV-2 into a host-cell occurs by means of its association with the angiotensin-converting enzyme-2 (ACE 2). Stimulating immune responses the COVID-19 infection causes the cytokine storm, and may result in the lethal outcome in the diabetics.

Recent laboratory studies demonstrated that the type1 and type2 diabetes mellitus is the main consequence in 14% of the patients after corona infection. Thus, in 2% of 14% diabetes started progressing due to the corona virus. In the other, diabetes debut occurred as the direct and negative consequence of the disease. Hyperglycemia results in the formation of protein molecules known as the advanced glycation end products (AGEs). The AGEs and their receptors (RAGE) are of high significance in the host-cell’s virus invasion. Consequently, more strict glucose control is necessary for optimal outcome and reduction in mortality. The better control for the COVID-19 course can be provided by the targeted effect on the RAGE axis. The review helps elucidate the molecular mechanism underlying the exacerbation of pathophysiology in the diabetic COVID-19 patients.

Non-anticoagulant heparin derivatives for COVID-19 treatment

The ongoing pandemic of COVID-19, caused by the infection of SARS-CoV-2, has generated significant harm to the world economy and taken numerous lives. This syndrome is characterized by an acute inflammatory response, mainly in the lungs and kidneys. Accumulated evidence suggests that exogenous heparin might contribute to the alleviation of COVID-19 severity through anticoagulant and various non-anticoagulant mechanisms, including heparanase inhibition, chemokine and cytokine neutralization, leukocyte trafficking interference, viral cellular-entry obstruction, and extracellular cytotoxic histone neutralization. However, the side effects of heparin and potential drawbacks of administering heparin therapy need to be considered. Here, the current heparin therapy drawbacks were covered in great detail: structure-activity relationship (SAR) mystery, potential contamination, and anticoagulant activity. Considering these unfavorable effects, specific non-anticoagulant heparin derivatives with antiviral activity could be promising candidates to treat COVID-19. Furthermore, a structurally diverse library of non-anticoagulant heparin derivatives, constructed by chemical modification and enzymatic depolymerization, would contribute to a deeper understanding of SAR mystery. In short, targeting non-anticoagulant mechanisms may produce better therapeutic effects, overcoming the side effects in patients suffering from COVID-19 and other inflammatory disorders.

In-stent Thrombosis and COVID-19 Infection: Current Insights on the Mechanistic Relationship

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been demonstrated as a major risk factor in inducing coronary stent thrombosis due to its propensity to create a pro-thrombotic state. This review explores the mechanisms that may contribute to the increased thrombosis risk seen in COVID-19. Furthermore, we discuss the patient and haematological factors that predispose to an increased risk of stent thrombosis, as well as the role of certain antiplatelet and anticoagulation therapies, including ticagrelor and enoxaparin, that may reduce the likelihood and severity of in-stent thrombosis, in SARS-CoV-2 infection. To counter the proinflammatory and pro-thrombotic state shown in COVID-19, anti-thrombotic therapy in the future may be optimised using point-of-care platelet inhibition testing and inflammation-modifying therapies. Large-scale randomised trials with long-term follow-up are increasingly necessary to assess the intersection of COVID-19 and stent optimisation as well as the reduction of stent thrombosis after drug-eluting stent (DES) implantation.

Not Just Anticoagulation—New and Old Applications of Heparin

In recent decades, heparin, as the most important anticoagulant drug, has been widely used in clinical settings to prevent and treat thrombosis in a variety of diseases. However, with in-depth research, the therapeutic potential of heparin is being explored beyond anticoagulation. To date, heparin and its derivatives have been tested in the protection against and repair of inflammatory, antitumor, and cardiovascular diseases. It has also been explored as an antiangiogenic, preventive, and antiviral agent for atherosclerosis. This review focused on the new and old applications of heparin and discussed the potential mechanisms explaining the biological diversity of heparin.

Extracellular traps and the role in thrombosis

Thrombotic complications pose serious health risks worldwide. A significant change in our understanding of the pathophysiology of thrombosis has occurred since the discovery of extracellular traps (ETs) and their prothrombotic properties. As a result of immune cells decondensing chromatin into extracellular fibers, ETs promote thrombus formation by acting as a scaffold that activates platelets and coagulates them. The involvement of ETs in thrombosis has been reported in various thrombotic conditions including deep vein thrombosis (DVT), pulmonary emboli, acute myocardial infarction, aucte ischemic stroke, and abdominal aortic aneurysms. This review summarizes the existing evidence of ETs in human and animal model thrombi. The authors described studies showing the existence of ETs in venous or arterial thrombi. In addition, we studied potential novel therapeutic opportunities related to the resolution or prevention of thrombosis by targeting ETs.

COVID-19 and Thrombosis Complication in Children

Since it was discovered in Wuhan in December 2019, most studies on COVID-19 have been centered on symptomatic adults. An expanded pro-inflammatory cytokine reaction, abnormal clot formation, overactive platelets, and hypercoagulable state are among the well-known clinical characteristics of endothelial dysfunction that may arise in patients with COVID-19. These conditions can lead to venous thromboembolism, arterial thrombosis, and pulmonary embolism. To date, the predominance of thromboembolic complications in children infected with severe acute respiratory syndrome coronavirus 2 has not been fully documented, and there is no explicit recommendation for the prevention of thrombosis in children.

SAGE: Novel Therapy to Reduce Inflammation in a Naturally Occurring-Dog Model of Periodontal Disease

Objective

Methods

Results

Conclusion

Neutrophil Extracellular Traps in Atherosclerosis and Thrombosis

Despite effective therapeutic and preventive strategies, atherosclerosis and its complications still represent a substantial health burden. Leukocytes and inflammatory mechanisms are increasingly recognized as drivers of atherosclerosis. Neutrophil granulocytes within the circulation were recently shown to undergo neutrophil extracellular trap (NET) formation, linking innate immunity with acute complications of atherosclerosis. In this chapter, we summarize mechanisms of NET formation, evidence for their involvement in atherosclerosis and thrombosis, and potential therapeutic regimens specifically targeting NET components.

HMGB1 Inhibition to Ameliorate Organ Failure and Increase Survival in Trauma

Several preclinical and clinical reports have demonstrated that levels of circulating high mobility group box 1 protein (HMGB1) are increased early after trauma and are associated with systemic inflammation and clinical outcomes. However, the mechanisms of the interaction between HMGB1 and inflammatory mediators that lead to the development of remote organ damage after trauma remain obscure. HMGB1 and inflammatory mediators were analyzed in plasma from 54 combat casualties, collected on admission to a military hospital in Iraq, and at 8 and 24 h after admission. In total, 45 (83%) of these patients had traumatic brain injury (TBI). Nine healthy volunteers were enrolled as controls. HMGB1 plasma levels were significantly increased in the first 8 h after admission, and were found to be associated with systemic inflammatory responses, injury severity score, and presence of TBI. These data provided the rationale for designing experiments in rats subjected to blast injury and hemorrhage, to explore the effect of HMGB1 inhibition by CX-01 (2-O, 3-O desulfated heparin). Animals were cannulated, then recovered for 5–7 days before blast injury in a shock tube and volume-controlled hemorrhage. Blast injury and hemorrhage induced an early increase in HMGB1 plasma levels along with severe tissue damage and high mortality. CX-01 inhibited systemic HMGB1 activity, decreased local and systemic inflammatory responses, significantly reduced tissue and organ damage, and tended to increase survival. These data suggest that CX-01 has potential as an adjuvant treatment for traumatic hemorrhage.

Combination of dociparstat sodium (DSTAT), a CXCL12/CXCR4 inhibitor, with azacitidine for the treatment of hypomethylating agent refractory AML and MDS

Leukemia stem cells utilize cell adhesion molecules like CXCR4/CXCL12 to home to bone marrow stromal niches where they are maintained in a dormant, protected state. Dociparstat sodium (DSTAT, CX-01) is a low anticoagulant heparin with multiple mechanisms of action, including inhibition of the CXCR4/CXCL12 axis, blocking HMGB1, and binding platelet factor 4 (PF-4). We conducted a pilot study adding DSTAT to azacitidine for patients with AML or MDS unresponsive to or relapsed after prior hypomethylating agent therapy, hypothesizing that DSTAT may improve response rates. Twenty patients were enrolled, with a median of 2 prior lines of therapy and 6 cycles of prior hypomethylating agents. Among fifteen patients evaluable for response, there was 1 complete remission, and 3 marrow complete remissions, for a response rate of 27 % among evaluable patients (20 % overall). Hematologic improvement was observed in 5 additional patients. The median overall survival for all enrolled patients was 205 days (95 % CI 119-302). While cytopenias and infections were common, these were not out of proportion to what would be expected in this population of patients undergoing treatment with azacitidine alone. In summary, this trial demonstrated the feasibility of combining DSTAT with azacitidine, with several responses observed, suggesting this combination warrants further study.

Neutrophil Elastase and Chronic Lung Disease

Neutrophil elastase (NE) is a major inflammatory protease released by neutrophils and is present in the airways of patients with cystic fibrosis (CF), chronic obstructive pulmonary disease, non-CF bronchiectasis, and bronchopulmonary dysplasia. Although NE facilitates leukocyte transmigration to the site of infection and is required for clearance of Gram-negative bacteria, it also activates inflammation when released into the airway milieu in chronic inflammatory airway diseases. NE exposure induces airway remodeling with increased mucin expression and secretion and impaired ciliary motility. NE interrupts epithelial repair by promoting cellular apoptosis and senescence and it activates inflammation directly by increasing cytokine expression and release, and indirectly by triggering extracellular trap release and exosome release, which magnify protease activity and inflammation in the airway. NE inhibits innate immune function by digesting opsonins and opsonin receptors, degrading innate immune proteins such as lactoferrin, and inhibiting macrophage phagocytosis. Importantly, NE-directed therapies have not yet been effective in preventing the pathologic sequelae of NE exposure, but new therapies are being developed that offer both direct antiprotease activity and multifunctional anti-inflammatory properties.

Venestatin from parasitic helminths interferes with receptor for advanced glycation end products (RAGE)-mediated immune responses to promote larval migration

Parasitic helminths can reside in humans owing to their ability to disrupt host protective immunity. Receptor for advanced glycation end products (RAGE), which is highly expressed in host skin, mediates inflammatory responses by regulating the expression of pro-inflammatory cytokines and endothelial adhesion molecules. In this study, we evaluated the effects of venestatin, an EF-hand Ca²⁺-binding protein secreted by the parasitic helminth Strongyloides venezuelensis, on RAGE activity and immune responses. Our results demonstrated that venestatin bound to RAGE and downregulated the host immune response. Recombinant venestatin predominantly bound to the RAGE C1 domain in a Ca²⁺-dependent manner. Recombinant venestatin effectively alleviated RAGE-mediated inflammation, including footpad edema in mice, and pneumonia induced by an exogenous RAGE ligand. Infection experiments using S. venezuelensis larvae and venestatin silencing via RNA interference revealed that endogenous venestatin promoted larval migration from the skin to the lungs in a RAGE-dependent manner. Moreover, endogenous venestatin suppressed macrophage and neutrophil accumulation around larvae. Although the invasion of larvae upregulated the abundance of RAGE ligands in host skin tissues, mRNA expression levels of tumor necrosis factor-α, cyclooxygenase-2, endothelial adhesion molecules vascular cell adhesion protein-1, intracellular adhesion molecule-1, and E-selectin were suppressed by endogenous venestatin. Taken together, our results indicate that venestatin suppressed RAGE-mediated immune responses in host skin induced by helminthic infection, thereby promoting larval migration. The anti-inflammatory mechanism of venestatin may be targeted for the development of anthelminthics and immunosuppressive agents for the treatment of RAGE-mediated inflammatory diseases.

Parasitic helminths have evolved smart strategies to thrive in diverse hosts. For example, parasitic helminths secrete various immunomodulators in the host to establish successful tissue migration to their reproductive niche and chronic parasitism. Identification and functional analyses have revealed these immunomodulators may have potential therapeutic effects in the treatment of immune-related diseases. However, few immunomodulators from parasitic helminths have been identified and analyzed to date. In this study, we determined that venestatin, an EF-hand Ca²⁺-binding protein secreted by the parasitic nematode Strongyloides venezuelensis, bound to receptor for advanced glycation end products (RAGE), a host pro-inflammatory receptor, which downregulated RAGE-mediated inflammatory responses. S. venezuelensis larvae successfully migrated to their niche owing to the anti-inflammatory functions of venestatin. Venestatin could provide a novel therapeutic target for the treatment of RAGE-mediated inflammatory diseases, such as Alzheimer’s disease, rheumatoid arthritis, asthma, ulcerative colitis, and diabetes.

The Trp triad within the V-domain of the receptor for advanced glycation end products modulates folding, stability and ligand binding

The receptor for advanced glycation end products (RAGE) recognizes damage-associated molecular patterns (DAMPs) and plays a critical role for the innate immune response and sterile tissue inflammation. RAGE overexpression is associated with diabetic complications, neurodegenerative diseases and certain cancers. Yet, the molecular mechanism of ligand recognition by RAGE is insufficiently understood to rationalize the binding of diverse ligands. The N-terminal V-type Ig-domain of RAGE contains a triad of tryptophan residue; Trp⁵¹, Trp⁶¹ and Trp⁷². The role of these three Trp residues for domain folding, stability and binding of the RAGE ligand S100B was investigated through site-directed mutagenesis, UV/VIS, CD and fluorescence spectrometry, protein–protein interaction studies, and X-ray crystallography. The data show that the Trp triad stabilizes the folded V-domain by maintaining a short helix in the structure. Mutation of any Trp residue increases the structural plasticity of the domain. Residues Trp⁶¹ and Trp⁷² are involved in the binding of S100B, yet they are not strictly required for S100B binding. The crystal structure of the RAGE-derived peptide W72 in complex with S100B showed that Trp⁷² is deeply buried in a hydrophobic depression on the S100B surface. The studies suggest that multiple binding modes between RAGE and S100B exist and point toward a not previously recognized role of the Trp residues for RAGE-ligand binding. The Trp triad of the V-domain appears to be a suitable target for novel RAGE inhibitors, either in the form of monoclonal antibodies targeting this epitope, or small organic molecules.

Enoxaparin Attenuates Acute Lung Injury and Inflammasome Activation after Traumatic Brain Injury

Traumatic brain injury (TBI) patients frequently develop cardiopulmonary system complications such as acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). However, the mechanism by which TBI causes ALI/ARDS is not fully understood. Here, we used a severe TBI model to examine the effects of a low-molecular-weight heparin, enoxaparin, on inflammasome activation and lung injury damage. We investigated whether enoxaparin inhibits ALI and inflammasome signaling protein expression in the brain and lungs after TBI in mice. C57/BL6 mice were subjected to severe TBI and were treated with vehicle or 1 mg/kg of enoxaparin 30 min after injury. Lung and brain tissue were collected 24 h post-TBI and were analyzed by immunoblotting for expression of the inflammasome proteins, caspase-1 and interleukin (IL)-1β. In addition, lung tissue was collected for histological analysis to determine ALI scoring and neutrophil and macrophage infiltration post-injury. Our data show that severe TBI induces increased expression of inflammasome proteins caspase-1 and IL-1β in the brain and lungs of mice after injury. Treatment with enoxaparin attenuated inflammasome expression in the brain and lungs 24 h after injury. Enoxaparin significantly decreased ALI score as well as neutrophil and macrophage infiltration in lungs at 24 h after injury. This study demonstrates that enoxaparin attenuates ALI and inhibits inflammasome expression in the brain and lungs after TBI. These findings support the hypothesis that inhibition of the neural-respiratory inflammasome axis that is activated after TBI may have therapeutic potential.

Polysulfated Hyaluronan GlycoMira-1111 Inhibits Elastase and Improves Rheology in Cystic Fibrosis Sputum

Cystic fibrosis (CF) lung disease is marked by high concentrations of neutrophil elastase (NE) and DNA polymers; both factors contribute to airway disease. Although inhaled recombinant human dornase alfa reduces the frequency of CF pulmonary exacerbations, it also increases free NE activity in the sputum. There are no approved anti-NE therapies for patients with CF. We investigated whether synthetic, low-molecular weight polysulfated hyaluronan GlycoMira-1111 (GM-1111) would be effective as an anti-NE drug using ex vivo CF sputum. Anti-NE activity of GM-1111 was tested in CF sputum in the presence or absence of dornase alfa and/or hypertonic saline using a spectrophotometric assay specific for human NE and was compared with unfractionated heparin. We tested whether GM-1111 disaggregated DNA from CF sputum (using gel electrophoresis analysis) or modified CF sputum viscoelastic properties (using a dynamic rheometer). GM-1111 and unfractionated heparin had near equivalent anti-NE activity in CF sputum in the presence of dornase alfa. Both GM-1111 and unfractionated heparin retained anti-NE activity in hypertonic saline but with decreased activity. GM-1111 increased the release of soluble DNA in CF sputum, resulting in improved depolymerization efficacy of dornase alfa. GM-1111 decreased CF sputum elasticity. GM-1111 inhibited NE activity, enhanced DNA depolymerization by deoxyribonuclease, and decreased viscoelastic properties of CF sputum, similar to effects reported previously for unfractionated heparin. Unlike heparins, GM-1111 is synthetic, with minimal anticoagulant activity, and is not derived from animal products. These key attributes provide advantages over unfractionated heparin as a potential therapeutic for CF.

Design and Rationale of a Randomized, Double-Blind, Placebo-Controlled, Phase 2/3 Study Evaluating Dociparstat in Acute Lung Injury Associated with Severe COVID-19

INTRODUCTION

The COVID-19 global pandemic caused by the novel coronavirus, SARS-CoV-2, and the consequent morbidity and mortality attributable to progressive hypoxemia and subsequent respiratory failure threaten to overrun hospital critical care units globally. New agents that address the hyperinflammatory "cytokine storm" and hypercoagulable pathology seen in these patients may be a promising approach to treat patients, minimize hospital stays, and ensure hospital wards and critical care units are able to operate effectively. Dociparstat sodium (DSTAT) is a glycosaminoglycan derivative of heparin with robust anti-inflammatory properties, with the potential to address underlying causes of coagulation disorders with substantially reduced risk of bleeding compared to commercially available heparin.

METHODS

This study is a randomized, double-blind, placebo-controlled, phase 2/3 trial to determine the safety and efficacy of DSTAT added to standard of care in hospitalized adults with COVID-19 who require supplemental oxygen. Phase 2 will enroll 12 participants in each of two dose-escalating cohorts to confirm the safety of DSTAT in this population. Following review of the data, an additional 50 participants will be enrolled. Contingent upon positive results, phase 3 will enroll approximately 450 participants randomized to DSTAT or placebo. The primary endpoint is the proportion of participants who survive and do not require mechanical ventilation through day 28.

DISCUSSION

Advances in standard of care, recent emergency use authorizations, and positive data with dexamethasone have likely contributed to an increasing proportion of patients who are surviving without the need for mechanical ventilation. Therefore, examining the time to improvement in the NIAID score will be essential to provide a measure of drug effect on recovery. Analysis of additional endpoints, including supportive biomarkers (e.g., IL-6, HMGB1, soluble-RAGE, D-dimer), will be performed to further define the effect of DSTAT in patients with COVID-19 infection.

TRIAL REGISTRATION

ClinicalTrials.gov identifier; NCT04389840, Registered 13 May 2020.

Venous thromboembolism and bleeding in critically ill COVID-19 patients treated with higher than standard low molecular weight heparin doses and aspirin: A call to action

Background

Critically ill COVID-19 patients have a clear pattern of inflammation and hypercoagulable state. The main aim of the study was to evaluate the outcome of severe COVID-19 patients basing on prothrombotic risk factors (i.e. D-dimer). We also evaluated the impact of different doses of low molecular weight heparin (LMWH) on the incidence of bleedings.

Methods

The data of forty-two patients admitted to the Intensive Care Unit (ICU) were retrospectively analyzed. On ICU admission, patients with D-dimer < 3000 ng/mL (Group 1) received enoxaparin 4000 UI (6000 UI, if body mass index >35) subcutaneously b.i.d. and patients with D-dimer ≥ 3000 ng/mL (Group 2) received enoxaparin 100 UI/kg every 12 h. Aspirin was administered to all patients once a day.

Results

Both groups presented a high incidence of perivascular thrombosis (40.9% in Group 1 and 30% in Group 2). Patients of Group 2 suffered a higher incidence of venous thromboembolism (VTE) than Group 1 (65% vs 13.6%, p = 0.001). One patient (4.5%) of Group 1 and three patients (15%) of Group 2 suffered from minor bleeding; no patient had major bleeding. Group 2 had a longer ICU and hospital stay than Group 1 (11.5 ± 5.6 vs 9.0 ± 4.8 and 30 ± 4.9 vs 21 ± 2.3, p < 0.05, respectively) as well as increased ICU mortality (25% vs 9.1%).

Conclusions

More severe critically ill COVID-19 patients have a high incidence of VTE and worse outcome, despite the use of heparin at the therapeutic dose. However, the use of heparin did not increase the incidence of bleeding complications.

•

Risk stratification based on D-dimer values is fundamental in critically ill patients with COVID-19 pneumonia.

•

High-risk patients have a higher incidence of thromboembolic events and worse outcome compared with low risk ones.

•

The use of heparin in therapeutic doses did not lead to an increase of bleeding risk.

Targeting CXCR4 in AML and ALL

The interaction of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) blasts with the bone marrow microenvironment regulates self-renewal, growth signaling, as well as chemotherapy resistance. The chemokine receptor, CXC receptor 4 (CXCR4), with its ligand chemokine ligand 12 (CXCL12), plays a key role in the survival and migration of normal and malignant stem cells to the bone marrow. High expression of CXCR4 on AML and ALL blasts has been shown to be a predictor of poor prognosis for these diseases. Several small molecule inhibitors, short peptides, antibodies, and antibody drug conjugates have been developed for the purposes of more effective targeting and killing of malignant cells expressing CXCR4. In this review we will discuss recent results and strategies in targeting CXCR4 with these agents in patients with AML or ALL.

Prothrombin is a binding partner of the human receptor of advanced glycation end products

The receptor for advanced glycation end products (RAGE) plays a key role in mammal physiology and in the etiology and progression of inflammatory and oxidative stress-based diseases. In adults, RAGE expression is normally high only in the lung where the protein concentrates in the basal membrane of alveolar Type I epithelial cells. In diseases, RAGE levels increase in the affected tissues and sustain chronic inflammation. RAGE exists as a membrane glycoprotein with an ectodomain, a transmembrane helix, and a short carboxyl-terminal tail, or as a soluble ectodomain that acts as a decoy receptor (sRAGE). VC1 domain is responsible for binding to the majority of RAGE ligands including advanced glycation end products (AGEs), S100 proteins, and HMGB1. To ascertain whether other ligands exist, we analyzed by MS the material pulled down by VC1 from human plasma. Twenty of 295 identified proteins were selected and associated to coagulation and complement processes and to extracellular matrix. Four of them contained a γ-carboxyl glutamic acid (Gla) domain, a calcium-binding module, and prothrombin (PT) was the most abundant. Using MicroScale thermophoresis, we quantified the interaction of PT with VC1 and sRAGE in the absence or presence of calcium that acted as a competitor. PT devoid of the Gla domain (PT des-Gla) did not bind to sRAGE, providing further evidence that the Gla domain is critical for the interaction. Finally, the presence of VC1 delayed plasma clotting in a dose-dependent manner. We propose that RAGE is involved in modulating blood coagulation presumably in conditions of lung injury.

Leukemia Stem Cell Release From the Stem Cell Niche to Treat Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous, complex, and deadly disease, whose treatment has hardly evolved for decades and grounds on the use of intensive chemotherapy regimens. Chemotherapy helps reduce AML bulk, but promotes relapse in the long-run by selection of chemoresistant leukemia stem cells (LSC). These may diversify and result in progression to more aggressive forms of AML. In vivo models suggest that the bone marrow stem cell niche helps LSC stay dormant and protected from chemotherapy. Here, we summarize relevant changes in stem cell niche homing and adhesion of AML LSC vs. healthy hematopoietic stem cells, and provide an overview of clinical trials aiming at targeting these processes for AML treatment and future directions within this field. Promising results with various non-mutation-targeted novel therapies directed to LSC eradication via interference with their anchoring to the stem cell niche have encouraged on-going or future advanced phase III clinical trials. In the coming years, we may see a shift in the focus of AML treatment to LSC-directed therapies if the prospect of improved cure rates holds true. In the future, AML treatment should lean toward personalized therapies using combinations of these compounds plus mutation-targeted agents and/or targeted delivery of chemotherapy, aiming at LSC eradication with reduced side effects.

Glycosaminoglycans as Multifunctional Anti-Elastase and Anti-Inflammatory Drugs in Cystic Fibrosis Lung Disease

Neutrophil elastase (NE) is a major protease in the airways of patients with cystic fibrosis (CF) that activates airway inflammation by several mechanisms. NE stimulates epithelial toll like receptors (TLR) resulting in cytokine upregulation and release, upregulates MUC5AC, a major airway mucin, degrades both phagocytic receptors and opsonins resulting in both neutrophil and macrophage phagocytic failure, generates oxidative stress via extracellular generation and uptake of heme free iron, and activates other proteases. Altogether, these mechanisms create a significant inflammatory challenge that impairs innate immune function and results in airway remodeling. Currently, a major gap in our therapeutic approach to CF lung disease is the lack of an effective therapeutic strategy targeting active NE and its downstream pro-inflammatory sequelae. Polysulfated glycosaminoglycans (GAGs) are potent anti-elastase drugs that have additional anti-inflammatory properties. Heparin is a prototype of a glycosaminoglycan with both anti-elastase and anti-inflammatory properties. Heparin inhibits NE in an allosteric manner with high potency. Heparin also inhibits cathepsin G, blocks P-selectin and L-selectin, hinders ligand binding to the receptor for advanced glycation endproducts, and impedes histone acetyltransferase activity which dampens cytokine transcription and High Mobility Group Box 1 release. Furthermore, nebulized heparin treatment improves outcomes for patients with chronic obstructive pulmonary disease (COPD), asthma, acute lung injury and smoke inhalation. However, the anticoagulant activity of heparin is a potential contraindication for this therapy to be developed for CF lung disease. Therefore, modified heparins and other GAGs are being developed that retain the anti-elastase and anti-inflammatory qualities of heparin with minimal to no anticoagulant activity. The modified heparin, 2-O, 3-O desulfated heparin (ODSH), maintains anti-elastase and anti-inflammatory activities in vitro and in vivo, and has little residual anticoagulant activity. Heparan sulfate with O-sulfate residues but not N-sulfate residues blocks allergic asthmatic inflammation in a murine model. Polysulfated hyaluronic acid abrogates allergen- triggered rhinosinusitis in a murine model. Finally, nonsaccharide glycosaminoglycan mimetics with specific sulfate modifications can be designed to inhibit NE activity. Altogether, these novel GAGs or GAG mimetics hold significant promise to address the unmet need for inhaled anti-elastase and anti-inflammatory therapy for patients with CF.

Anticoagulant activity and pleiotropic effects of heparin

The recognized therapeutic effect of heparins is an anticoagulant activity (anti-Xa and anti-IIa) acting in an indirect manner (cofactor of antithrombin) but which is carried by only 20% at best of the glycan chains composing any commercial preparation of heparin, whether unfractionated or low molecular weight. However, the effects of glycan chains that participate in the therapeutic but also potentially adverse effects of heparin preparations must also be considered. These specific effects of glycans are potentially different for each commercial preparation of heparins and, in particular, low molecular weight heparins (LMWH) compared with unfractionated heparin (UFH) and LMWH between them. The glycanic nature of heparin is responsible for its very particular pharmacology: exchange with the glycocalyx of cells in particular endothelial. Exchanges which depend on the length and structure of the glycan chains therefore different between UFH and LMWH between the different heparin preparations between them but also according to the state of glycocalyx differently altered according to the underlying diseases and their degree of evolution. If the anticoagulant effects of heparins can potentially be replaced with those of new oral anticoagulants, the glycan effects of heparins cannot be replaced by synthetic non-glycan molecules. This replacement will undoubtedly limit certain risks such as heparin-induced thrombocytopenia (HIT) but other beneficial effects participating to the overall efficacy of heparin (whose relative importance remains to be ascertained), will also disappear: effects on surfaces, anti-inflammatory effects, antineoplastic and anti-metastatic effects, ancillary anticoagulant effects (not dependent on antithrombin), effect on endothelial dysfunction. This review will be focused on all of these related/pleiotropic effects of heparins that are in fact the effects of the glycan nature of heparin. Among the antithrombotic effects not dependent on antithrombin one has been more recently highlighted: the passivation/neutralization of the positively charged fibrils of Netosis, by the negatively charged glycan chains of heparin. This also has clinical implications: in the era of generics and biosimilars where biosimilar heparins begin to appear, it is important to know that accordingly to FDA and EMEA rules: their biosimilarity is judged only on the "classical" anticoagulation effect cofactor of antithrombin (anti-IIa/anti-Xa) but that all glycan effects that are potentially beneficial or potentially deleterious are not taken into consideration in their assessment.

Alpha-1 Antitrypsin-A Target for MicroRNA-Based Therapeutic Development for Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal recessive genetic disorder arising from mutations to the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Disruption to normal ion homeostasis in the airway results in impaired mucociliary clearance, leaving the lung more vulnerable to recurrent and chronic bacterial infections. The CF lung endures an excess of neutrophilic inflammation, and whilst neutrophil serine proteases are a crucial part of the innate host defence to infection, a surplus of neutrophil elastase (NE) is understood to create a net destructive effect. Alpha-1 antitrypsin (A1AT) is a key antiprotease in the control of NE protease activity but is ineffective in the CF lung due to the huge imbalance of NE levels. Therapeutic strategies to boost levels of protective antiproteases such as A1AT in the lung remain an attractive research strategy to limit the damage from excess protease activity. microRNAs are small non-coding RNA molecules that bind specific cognate sequences to inhibit expression of target mRNAs. The inhibition of miRNAs which target the SERPINA1 (A1AT-encoding gene) mRNA represents a novel therapeutic approach for CF inflammation. This could involve the delivery of antagomirs that bind and sequester the target miRNA, or target site blockers that bind miRNA recognition elements within the target mRNA to prevent miRNA interaction. Therefore, miRNA targeted therapies offer an alternative strategy to drive endogenous A1AT production and thus supplement the antiprotease shield of the CF lung.

Non-Anticoagulant Heparins as Heparanase Inhibitors

The chapter will review early and more recent seminal contributions to the discovery and characterization of heparanase and non-anticoagulant heparins inhibiting its peculiar enzymatic activity. Indeed, heparanase displays a unique versatility in degrading heparan sulfate chains of several proteoglycans expressed in all mammalian cells. This endo-β-D-glucuronidase is overexpressed in cancer, inflammation, diabetes, atherosclerosis, nephropathies and other pathologies. Starting from known low- or non-anticoagulant heparins, the search for heparanase inhibitors evolved focusing on structure-activity relationship studies and taking advantage of new chemical-physical analytical methods which have allowed characterization and sequencing of polysaccharide chains. New methods to screen heparanase inhibitors and to evaluate their mechanism of action and in vivo activity in experimental models prompted their development. New non-anticoagulant heparin derivatives endowed with anti-heparanase activity are reported. Some leads are under clinical evaluation in the oncology field (e.g., acute myeloid leukemia, multiple myeloma, pancreatic carcinoma) and in other pathological conditions (e.g., sickle cell disease, malaria, labor arrest).

Identification of a heparosan heptasaccharide as an effective anti-inflammatory agent by partial desulfation of low molecular weight heparin

Low molecular weight heparin (LMWH) possesses a dual function of anticoagulation and anti-inflammation. While the structures and mechanisms on its anticoagulation have been widely studied, the structural features responsible for the anti-inflammatory activity of LMWH remain to be explored. In the present study, guided by an anti-inflammation assay, a non-anticoagulant species was generated from partial desulfation of LMWH to fully retain the anti-inflammatory activity, from which five fractions were further separated and three of them were characterized by enzymatic degradation, hydrophobic labeling, C18-based HPLC and LC-MS/MS analyses. The structure-activity relationship revealed that the sulfate groups in LMWH are critical to distinguish and separate the activities of anticoagulation and anti-inflammation, leading to the identification of a synthetic heparosan-type heptasaccharide as a potent anti-inflammatory agent. The present strategy enables the simplification of complex polysaccharides to bioactive synthetic oligosaccharides for therapeutic utility.

Heparinoid sevuparin inhibits Streptococcus-induced vascular leak through neutralizing neutrophil-derived proteins

Acute lung injury (ALI) and respiratory distress can develop as a consequence of sepsis with pathogens such as group A Streptococcus (GAS). In the pathogenesis of sepsis-associated ALI, endothelial barrier disruption brought on by phagocyte activation is considered a causative factor. Here, we find that sevuparin, a heparinoid with low anticoagulant activity, prevents neutrophil-induced lung plasma leakage in a murine model of systemic inflammation evoked by heat-killed GAS (hkGAS). Furthermore, using human neutrophils and endothelial cell monolayers, we demonstrate that sevuparin inhibits hkGAS-induced endothelial barrier disruption by neutralizing the activity of neutrophil-derived proteins. By mass spectrometry of neutrophil secretion, we identify proteins, including serprocidins, S100 proteins, and histone H4, that interact with sevuparin and that are responsible for the disruptive effect on endothelial integrity. Collectively, our results demonstrate the critical role of neutrophil-derived proteins in vascular hyperpermeability caused by GAS and suggest sevuparin as a potential therapeutic in acute neutrophilic inflammation.-Rasmuson, J., Kenne, E., Wahlgren, M., Soehnlein, O., Lindbom, L. Heparinoid sevuparin inhibits Streptococcus-induced vascular leak through neutralizing neutrophil-derived proteins.

Leukocyte Heparanase: A Double-Edged Sword in Tumor Progression

Heparanase is a β-D-endoglucuronidase that cleaves heparan sulfate, a complex glycosaminoglycan found ubiquitously throughout mammalian cells and tissues. Heparanase has been strongly associated with important pathological processes including inflammatory disease and tumor metastasis, through its ability to promote various cellular functions such as cell migration, invasion, adhesion, and cytokine release. A number of cell types express heparanase including leukocytes, cells of the vasculature as well as tumor cells. However, the relative contribution of heparanase from these different cell sources to these processes is poorly defined. It is now well-established that the immune system plays a critical role in shaping tumor progression. Intriguingly, leukocyte-derived heparanase has been shown to either assist or impede tumor progression, depending on the setting. This review covers our current knowledge of heparanase in immune regulation of tumor progression, as well as the potential applications and implications of exploiting or inhibiting heparanase in cancer therapy.

Early low-anticoagulant desulfated heparin after traumatic brain injury: Reduced brain edema and leukocyte mobilization is associated with improved watermaze learning ability weeks after injury

BACKGROUND

Unfractionated heparin administered immediately after traumatic brain injury (TBI) reduces brain leukocyte (LEU) accumulation, and enhances early cognitive recovery, but may increase bleeding after injury. It is unknown how non-anticoagulant heparins, such as 2,3-O desulfated heparin (ODSH), impact post-TBI cerebral inflammation and long-term recovery. We hypothesized that ODSH after TBI reduces LEU-mediated brain inflammation and improves long-term neurologic recovery.

METHODS

CD1 male mice (n = 66) underwent either TBI (controlled cortical impact [CCI]) or sham craniotomy. 2,3-O desulfated heparin (25 mg/kg [25ODSH] or 50 mg/kg [50ODSH]) or saline was administered for 48 hours after TBI in 46 animals. At 48 hours, intravital microscopy visualized rolling LEUs and fluorescent albumin leakage in the pial circulation, and the Garcia Neurologic Test assessed neurologic function. Brain edema (wet/dry ratio) was evaluated post mortem. In a separate group of animals (n = 20), learning/memory ability (% time swimming in the Probe platform quadrant) was assessed by the Morris Water Maze 17 days after TBI. Analysis of variance with Bonferroni correction determined significance (p < 0.05).

RESULTS

Compared with CCI (LEU rolling: 32.3 ± 13.7 LEUs/100 μm per minute, cerebrovascular albumin leakage: 57.4 ± 5.6%), both ODSH doses reduced post-TBI pial LEU rolling (25ODSH: 18.5 ± 9.2 LEUs/100 μm per minute, p = 0.036; 50ODSH: 7.8 ± 3.9 LEUs/100 μm per minute, p < 0.001) and cerebrovascular albumin leakage (25ODSH: 37.9 ± 11.7%, p = 0.001, 50ODSH: 32.3 ± 8.7%, p < 0.001). 50ODSH also reduced injured cerebral hemisphere edema (77.7 ± 0.4%) vs. CCI (78.7 ± 0.4 %, p = 0.003). Compared with CCI, both ODSH doses improved Garcia Neurologic Test at 48 hours. Learning/memory ability (% time swimming in target quadrant) was lowest in CCI (5.9 ± 6.4%) and significantly improved in the 25ODSH group (27.5 ± 8.2%, p = 0.025).

CONCLUSION

2,3-O desulfated heparin after TBI reduces cerebral LEU recruitment, microvascular permeability and edema. 2,3-O desulfated heparin may also improve acute neurologic recovery leading to improved learning/memory ability weeks after injury.

2-O, 3-O desulfated heparin mitigates murine chemotherapy- and radiation-induced thrombocytopenia

Thrombocytopenia is a significant complication of chemotherapy and radiation therapy. Platelet factor 4 (PF4; CXCL4) is a negative paracrine of megakaryopoiesis. We have shown that PF4 levels are inversely related to steady-state platelet counts, and to the duration and severity of chemotherapy- and radiation-induced thrombocytopenia (CIT and RIT, respectively). Murine studies suggest that blocking the effect of PF4 improves megakaryopoiesis, raising nadir platelet counts and shortening the time to platelet count recovery. We examined the ability of 2-O, 3-O desulfated heparin (ODSH), a heparin variant with little anticoagulant effects, to neutralize PF4's effects on megakaryopoiesis. Using megakaryocyte colony assays and liquid cultures, we show that ODSH restored megakaryocyte proliferation in PF4-treated Cxcl4^-/- murine and human CD34⁺-derived megakaryocyte cultures (17.4% megakaryocyte colonies, P < .01 compared with PF4). In murine CIT and RIT models, ODSH, started 24 hours after injury, was examined for the effect on hematopoietic recovery demonstrating higher platelet count nadirs (9% ± 5% treated vs 4% ± 4% control) and significantly improved survival in treated animals (73% treated vs 36% control survival). Treatment with ODSH was able to reduce intramedullary free PF4 concentrations by immunohistochemical analysis. In summary, ODSH mitigated CIT and RIT in mice by neutralizing the intramedullary negative paracrine PF4. ODSH, already in clinical trials in humans as an adjuvant to chemotherapy, may be an important, clinically relevant therapeutic for CIT and RIT.

Combination of the low anticoagulant heparin CX-01 with chemotherapy for the treatment of acute myeloid leukemia

Relapses in acute myelogenous leukemia (AML) are a result of quiescent leukemic stem cells (LSCs) in marrow stromal niches, where they resist chemotherapy. LSCs employ CXCL12/CXCR4 to home toward protective marrow niches. Heparin disrupts CXCL12-mediated sequestration of cells in the marrow. CX-01 is a low-anticoagulant heparin derivative. In this pilot study, we combined CX-01 with chemotherapy for the treatment of AML. Induction consisted of cytarabine and idarubicin (7 + 3) with CX-01. Twelve patients were enrolled (median age, 56 years; 3 women). Three, 5, and 4 patients had good-, intermediate-, and poor-risk disease, respectively. Day 14 bone marrows were available on 11 patients and were aplastic in all without detectable leukemia. Eleven patients (92%) had morphologic complete remission after 1 induction (CR1). Eight patients were alive at a median follow-up of 24 months (4 patients in CR1). Three patients received an allogeneic stem cell transplant in CR1. Median disease-free survival was 14.8 months. Median overall survival was not attained at the maximum follow-up time of 29.4 months. No CX-01-associated serious adverse events occurred. Median day to an untransfused platelet count of at least 20 × 10⁹/L was 21. CX-01 is well tolerated when combined with intensive therapy for AML and appears associated with enhanced count recovery and treatment efficacy.

Design, synthesis, and biomedical applications of synthetic sulphated polysaccharides

This review summarizes the synthetic methods to sulphated polysaccharides, describes their compositional and structural diversity in regards to activity, and showcases their biomedical applications.

Heparan Sulfate Mimetics in Cancer Therapy: The Challenge to Define Structural Determinants and the Relevance of Targets for Optimal Activity

Beyond anticoagulation, the therapeutic potential of heparin derivatives and heparan sulfate (HS) mimetics (functionally defined HS mimetics) in oncology is related to their ability to bind and modulate the function of a vast array of HS-binding proteins with pivotal roles in cancer growth and progression. The definition of structural/functional determinants and the introduction of chemical modifications enabled heparin derivatives to be identified with greatly reduced or absent anticoagulant activity, but conserved/enhanced anticancer activity. These studies paved the way for the disclosure of structural requirements for the inhibitory effects of HS mimetics on heparanase, selectins, and growth factor receptor signaling, as well as for the limitation of side effects. Actually, HS mimetics affect the tumor biological behavior via a multi-target mechanism of action based on their effects on tumor cells and various components of the tumor microenvironment. Emerging evidence indicates that immunomodulation can participate in the antitumor activity of these agents. Significant ability to enhance the antitumor effects of combination treatments with standard therapies was shown in several tumor models. While the first HS mimetics are undergoing early clinical evaluation, an improved understanding of the molecular contexts favoring the antitumor action in certain malignancies or subgroups is needed to fully exploit their potential.

Role of advanced glycation end products in mobility and considerations in possible dietary and nutritional intervention strategies

Advanced glycation end products (AGEs), a group of compounds that are formed by non-enzymatic reactions between carbonyl groups of reducing sugars and free amino groups of proteins, lipids or nucleic acids, can be obtained exogenously from diet or formed endogenously within the body. AGEs accumulate intracellularly and extracellularly in all tissues and body fluids and can cross-link with other proteins and thus affect their normal functions. Furthermore, AGEs can interact with specific cell surface receptors and hence alter cell intracellular signaling, gene expression, the production of reactive oxygen species and the activation of several inflammatory pathways. High levels of AGEs in diet as well as in tissues and the circulation are pathogenic to a wide range of diseases. With respect to mobility, AGEs accumulate in bones, joints and skeletal muscles, playing important roles in the development of osteoporosis, osteoarthritis, and sarcopenia with aging. This report covered the related pathological mechanisms and the potential pharmaceutical and dietary intervention strategies in reducing systemic AGEs. More prospective studies are needed to determine whether elevated serum AGEs and/or skin autofluorescence predict a decline in measures of mobility. In addition, human intervention studies are required to investigate the beneficial effects of exogenous AGEs inhibitors on mobility outcomes.

A synthetic glycosaminoglycan reduces sinonasal inflammation in a murine model of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is characterized by sustained mucosal inflammation, impaired mucociliary clearance, loss of cilia and epithelial barrier breakdown, and tissue remodeling. Certain glycosaminoglycans inhibit various inflammatory mediators, suppress bacterial growth, and provide important functions in mucosal tissue repair and mucociliary clearance. Herein, we evaluated the effects of a synthetic glycosaminoglycan, GM-1111, on the clinical signs and inflammatory tissue changes associated with CRS in mice. CRS was generated by repeated intranasal applications of Aspergillus fumigatus (A. fumigatus) extracts over 4 weeks. Mice were then intranasally administered GM-1111 (600 μg per dose, 5 times a week) or vehicle (phosphate buffered saline, PBS) for an additional 4 weeks while still being given A. fumigatus extracts to maintain a chronic inflammatory environment with acute exacerbations. Clinical signs indicative of sinonasal inflammation were recorded throughout the study. After 9 weeks, whole blood and sinonasal tissues were harvested for hematological, histological, and biochemical examination. The clinical signs, white blood cell counts, tissue markers of sinonasal inflammation, and histological changes caused by A. fumigatus extract administration were compared to the healthy (PBS vehicle) and GM-1111-treated groups (n = 12 per treatment group). Compared to vehicle-treated animals, animals treated with GM-1111 demonstrated significant reductions in clinical signs (p<0.05), degenerative tissue changes, goblet cell hyperplasia, inflammatory cell infiltration (p<0.01), innate immunity- (tlr2, tlr4, myd88, il1b, tnfa, il6, and il12) and adaptive immunity-associated (ccl11, ccl24, ccl5, il4, il5, and il13) cytokine gene expression (p<0.05 to p<0.0001) in sinonasal tissues, and serum IgE levels (p<0.01). Our data suggest that GM-1111 significantly reduces local and systemic effects of CRS-associated sinonasal inflammation.

Inhibition of Homophilic Interactions and Ligand Binding of the Receptor for Advanced Glycation End Products by Heparin and Heparin-Related Carbohydrate Structures

Background: Heparin and heparin-related sulphated carbohydrates inhibit ligand binding of the receptor for advanced glycation end products (RAGE). Here, we have studied the ability of heparin to inhibit homophilic interactions of RAGE in living cells and studied how heparin related structures interfere with RAGE⁻ligand interactions. Methods: Homophilic interactions of RAGE were studied with bead aggregation and living cell protein-fragment complementation assays. Ligand binding was analyzed with microwell binding and chromatographic assays. Cell surface advanced glycation end product binding to RAGE was studied using PC3 cell adhesion assay. Results: Homophilic binding of RAGE was mediated by V₁- and modulated by C₂-domain in bead aggregation assay. Dimerisation of RAGE on the living cell surface was inhibited by heparin. Sulphated K5 carbohydrate fragments inhibited RAGE binding to amyloid β-peptide and HMGB1. The inhibition was dependent on the level of sulfation and the length of the carbohydrate backbone. α-d-Glucopyranosiduronic acid (glycyrrhizin) inhibited RAGE binding to advanced glycation end products in PC3 cell adhesion and protein binding assays. Further, glycyrrhizin inhibited HMGB1 and HMGB1 A-box binding to heparin. Conclusions: Our results show that K5 polysaccharides and glycyrrhizin are promising candidates for RAGE targeting drug development.

Molecular principles for heparin oligosaccharide-based inhibition of neutrophil elastase in cystic fibrosis

Cystic fibrosis (CF) is a multifactorial disease in which dysfunction of protease-antiprotease balance plays a key role. The current CF therapy relies on dornase α, hypertonic saline, and antibiotics and does not address the high neutrophil elastase (NE) activity observed in the lung and sputum of CF patients. Our hypothesis is that variants of heparin, which potently inhibit NE but are not anticoagulant, would help restore the protease-antiprotease balance in CF. To realize this concept, we studied molecular principles governing the effectiveness of different heparins, especially 2-O,3-O-desulfated heparin (ODSH), in the presence of sputum components and therapeutic agents. Using sputa from CF patients and an NE activity assay, we found that heparins are ineffective if used in the absence of dornase. This is true even when mucolytics, such as DTT or N-acetylcysteine, were used. Computational modeling suggested that ODSH and DNA compete for binding to an overlapping allosteric site on NE, which reduces the anti-NE potential of ODSH. NE inhibition of both DNA and ODSH is chain length-dependent, but ODSH chains exhibit higher potency per unit residue length. Likewise, ODSH chains exhibit higher NE inhibition potential compared with DNA chains in the presence of saline. These studies suggest fundamental differences in DNA and ODSH recognition and inhibition of NE despite engaging overlapping sites and offer unique insights into molecular principles that could be used in developing antiprotease agents in the presence of current treatments, such as dornase and hypertonic saline.

Transgenic up-regulation of Claudin-6 decreases fine diesel particulate matter (DPM)-induced pulmonary inflammation

Claudin-6 (Cldn6) is a tetraspanin transmembrane protein that contributes to tight junctional complexes and has been implicated in the maintenance of lung epithelial barriers. In the present study, we tested the hypothesis that genetic up-regulation of Cldn-6 influences inflammation in mice exposed to short-term environmental diesel particulate matter (DPM). Mice were subjected to ten exposures of nebulized DPM (PM2.5) over a period of 20 days via a nose-only inhalation system (Scireq, Montreal, Canada). Using real-time RT-PCR, we discovered that the Cldn6 gene was up-regulated in control mice exposed to DPM and in lung-specific transgenic mice that up-regulate Cldn-6 (Cldn-6 TG). Interestingly, DPM did not further enhance Cldn-6 expression in Cldn-6 TG mice. DPM caused increased cell diapedesis into bronchoalveolar lavage fluid (BALF) from control mice; however, Cldn-6 TG mice had less total cells and PMNs in BALF following DPM exposure. Because Cldn-6 TG mice had diminished cell diapedesis, other inflammatory intermediates were screened to characterize the impact of increased Cldn-6 on inflammatory signaling. Cytokines that mediate inflammatory responses including TNF-α and IL-1β were differentially regulated in Cldn6 TG mice and controls following DPM exposure. These results demonstrate that epithelial barriers organized by Cldn-6 mediate, at least in part, diesel-induced inflammation. Further work may show that Cldn-6 is a key target in understanding pulmonary epithelial gateways exacerbated by environmental pollution.