Treatment with unfractionated heparin attenuates coagulation and inflammation in endotoxemic mice

Low-molecular-weight heparin ameliorates intestinal barrier dysfunction in aged male rats via protection of tight junction proteins

The intestinal barrier weakens and chronic gut inflammation occurs in old age, causing age-related illnesses. Recent research shows that low-molecular-weight heparin (LMWH), besides anticoagulation, also has anti-inflammatory and anti-apoptotic effects, protecting the intestinal barrier. This study aims to analyze the effect of LMWH on the intestinal barrier of old male rodents. This study assigned Sprague-Dawley male rats to four groups: young (3 months), young + LMWH, old (20 months), and old + LMWH. The LMWH groups received 1 mg/kg LMWH via subcutaneous injection for 7 days. Optical and transmission electron microscopy (TEM) were used to examine morphological changes in intestinal mucosa due to aging. Intestinal permeability was measured using fluorescein isothiocyanate (FITC)-dextran. ELISA kits were used to measure serum levels of IL-6 and IL-1β, while Quantitative RT-PCR detected their mRNA levels in intestinal tissues. Western blotting and immunohistochemistry (IHC) evaluated the tight junction (TJ) protein levels such as occludin, zonula occludens-1 (ZO-1), and claudin-2. Western blotting assessed the expression of the apoptosis marker cleaved caspase 3, while IHC was used to detect LGR5+ intestinal stem cells. The intestinal permeability of aged rats was significantly higher than that of young rats, indicating significant differences. With age, the protein levels of occludin and ZO-1 decreased significantly, while the level of claudin-2 increased significantly. Meanwhile, our study found that the levels of IL-1β and IL-6 increased significantly with age. LMWH intervention effectively alleviated age-related intestinal barrier dysfunction. In aged rats treated with LMWH, the expression of occludin and ZO-1 proteins in the intestine increased, while the expression of claudin-2 decreased. Furthermore, LMWH administration in aged rats resulted in a decrease in IL-1β and IL-6 levels. LMWH also reduced age-related cleaved caspase3 expression, but IHC showed no difference in LGR5+ intestinal stem cells between groups. Research suggests that LMWH could potentially be a favorable therapeutic choice for age-related diseases associated with intestinal barrier dysfunction, by protecting TJ proteins, reducing inflammation, and apoptosis.

Efficacy and safety of heparin for sepsis-induced disseminated intravascular coagulation (HepSIC): study protocol for a multicenter randomized controlled trial

BACKGROUND

Disseminated intravascular coagulation (DIC) occurs in 30-50% of septic patients and contributes to high mortality in the intensive care unit (ICU). However, there are few proven interventions for coagulation disorder management in sepsis. Experimental and clinical data have demonstrated that sepsis could benefit from unfractionated heparin (UFH) treatment. To date, there are no large multicenter trials to determine the safety and efficacy of UFH in septic patients with suspected DIC.

METHODS

A multicenter, double-blinded, placebo-controlled randomized trial is designed to recruit 600 patients who met sepsis 3.0 criteria and suspected DIC. Participants will be randomized (1:1) to receive UFH or saline via continuous intravenous administration for 7 days within 6 h of enrolment. The primary outcome is ICU mortality. The secondary outcome includes 28-day all-cause mortality, the improvement of Sequential Organ Failure Assessment scores, and the incidence of major hemorrhage. Investigators, participants, and statisticians will be blinded to the allocation.

DISCUSSION

The HepSIC trial is to evaluate the efficacy and safety of UFH on sepsis-related DIC across different areas of China. The small dosage of UFH administration would offer a new potential approach for treating sepsis-related coagulation disorders.

ETHICS AND DISSEMINATION

Ethical approval was granted by all the ethics committees of 20 participant centers. Results will be disseminated via peer-reviewed publications and presented at conferences.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02654561. Registered on 13 January 2016.

Unfractionated Heparin Protects Microcirculation in Endotoxemic Rats by Antagonizing Histones

INTRODUCTION

Levels of extracellular histones are highly increased in sepsis and may facilitate microcirculatory dysfunction. Unfractionated heparin (UFH) binds histones and neutralizes their cytotoxicity. We investigated the effect of UFH on microcirculatory dysfunction by interacting with extracellular histones in endotoxemic rats.

METHODS

Twenty-four Wistar rats were randomly divided into three groups: control, lipopolysaccharide (LPS) group, and LPS + UFH group. In the LPS and LPS + UFH groups, 10 mg/kg LPS was injected to induce endotoxemia, and 100 IU/kg/h UFH was administered intravenously in the LPS + UFH group. The rats underwent midline laparotomy, and then intestinal microcirculation was evaluated using an incident dark field microscope. Circulating histones and microstructures of the rat intestinal microvascular endothelium were also detected. Additionally, the antagonistic effect of UFH on histone-induced cytotoxicity was investigated in human intestinal microvascular endothelial cells.

RESULTS

UFH protected the microcirculation of the intestinal serosa and mucosa in endotoxemic rats, as evidenced by increased total vessel density, perfused vessel density, and proportion of perfused vessels of both the serosa and mucosa, and increased microcirculatory flow index of the mucosa in the LPS + UFH group. UFH treatment decreased the levels of circulating histones and alleviated intestinal microvascular endothelial injuries in endotoxemic rats. Furthermore, UFH inhibited histone cytotoxicity in vitro.

CONCLUSIONS

UFH attenuated microcirculatory dysfunction in endotoxemic rats by antagonizing extracellular histones, thereby providing a potential therapeutic strategy for sepsis.

Management Strategies in Septic Coagulopathy: A Review of the Current Literature

One of the 'organs' that can be affected by sepsis is the coagulation system. Coagulopathy in sepsis may take the form of sepsis-induced coagulopathy (SIC) or sepsis-associated disseminated intravascular coagulation (DIC). It is important to identify SIC early, as at this stage of coagulopathy anticoagulants may be of the greatest benefit. The most recent diagnostic scoring systems for septic coagulopathy come from the International Society on Thrombosis and Hemostasis and the Japanese Association for Acute Medicine. Recommendations regarding the management of septic coagulopathy differ between organizations. Moreover, septic coagulopathy is an area of intense research in recent years. Therefore we searched three databases to review the most recent management strategies in septic coagulopathy. The mainstream management strategies in septic coagulopathy include the causal treatment of sepsis, unfractionated heparin, low-molecular-weight heparin, antithrombin, and recombinant human thrombomodulin. The last two have been associated with the highest survival benefit. Nevertheless, the indiscriminate use of these anticoagulants should be avoided due to the lack of mortality benefit and increased risk of bleeding. The early diagnosis of SIC and monitoring of coagulation status during sepsis is crucial for the timely management and selection of the most suitable treatment at a time. New directions in septic coagulopathy include new diagnostic biomarkers, dynamic diagnostic models, genetic markers for SIC management, and new therapeutic agents. These new research avenues may potentially result in timelier SIC diagnosis and improved management of all stages of septic coagulopathy by making it more effective, safe, and personalized.

Continuous Infusion Low-Dose Unfractionated Heparin for the Management of Hypercoagulability Associated With COVID-19

INTRODUCTION

The Coronavirus Disease 2019 (COVID-19) is associated with severe hypercoagulability. There is currently limited evidence supporting the routine use of therapeutic anticoagulation in the setting of COVID-19.

OBJECTIVES

The primary objective was to compare the incidence of thromboembolic events in adult patients with COVID-19 treated with an unfractionated heparin (UFH) infusion versus prophylactic dose anticoagulation. Secondary objectives included exploration of the efficacy and safety of an UFH infusion through the evaluation of organ function and incidence of minor and major bleeding.

METHODS

Retrospective observational cohort study with propensity score matching of COVID-19 patients who received an UFH infusion targeting an aPTT between 40 and 60 seconds.

RESULTS

Fifty-six patients were included in this study. There was no difference in the composite of thromboembolic events comprised of venous thromboembolism, arterial thrombosis, and catheter-related thrombosis between the UFH and control group (17.9% vs. 3.6%, P = 0.19). There was a significant increase in median D-dimer concentrations from day 1 to day 7 in the control group (475 ng/mL [291-999] vs. 10820 ng/mL [606-21033], P = 0.04). Patients treated with UFH had a higher incidence of minor bleeding (35.7% vs. 0%, P < 0.005) and required more units of packed red blood cell transfusion (0.8 units ± 1.6 vs. 0 units, P = 0.01).

CONCLUSION

Continuous infusion of UFH for patients with COVID-19 infection did not decrease the overall incidence of thromboembolic complications. UFH was associated with stabilization of D-dimer concentrations and increased rates of minor bleeding and transfusions.

Unfractionated heparin improves the clinical efficacy in adult sepsis patients: a systematic review and meta-analysis

Background

The anticoagulant treatment and clinical efficacy of heparin in sepsis remains controversial. We conducted a meta-analysis to estimate the clinical efficacy of unfractionated heparin (UFH) in adult septic patients.

Method

A systematic review of Medline, Cochrane Library, PubMed, Embase, WEIPU database, CNKI database, WANFANG database was performed from inception to January 2021. We included Randomized controlled trials (RCTs) and the main outcome was 28 d mortality. Data analysis was performed with Review Manager (RevMan) version 5.3 software. The meta-analysis included 2617 patients from 15 RCTs.

Results

Comparing to control group, UFH could reduce 28 d mortality (RR: 0.82; 95% CI: 0.72 to 0.94) especially for patient with Acute Physiology and Chronic Health Evaluation II (APACHE II) > 15, (RR: 0.83; 95% CI: 0.72 to 0.96). In UFH group, the platelet (PLT) (MD: 9.18; 95% CI: 0.68 to 17.68) was higher, the activated partial thromboplastin time (APTT) was shorter (MD: -8.01; 95% CI: − 13.84 to − 2.18) and the prothrombin time (PT) results (P > 0.05) failed to reach statistical significance. UFH decreased multiple organ dysfunction syndrome (MODS) incidence (RR: 0.61; 95% CI: 0.45 to 0.84), length of stay (LOS) in ICU (MD: -4.94; 95% CI: − 6.89 to − 2.99) and ventilation time (MD: -3.01; 95% CI: − 4.0 to − 2.02). And UFH had no adverse impact on bleeding (RR: 1.10; 95% CI: 0.54 to 2.23).

Conclusion

This meta-analysis suggests that UFH may reduce 28 d mortality and improve the clinical efficacy in sepsis patients without bleeding adverse effect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01545-w.

Protection and rebuilding of the endothelial glycocalyx in sepsis - Science or fiction?

The endothelial glycocalyx (eGC), a delicate carbohydrate-rich structure lining the luminal surface of the vascular endothelium, is vital for maintenance of microvascular homeostasis. In sepsis, damage of the eGC triggers the development of vascular hyperpermeability with consecutive edema formation and organ failure. While there is evidence that protection or rebuilding of the eGC might counteract sepsis-induced vascular leakage and improve outcome, approved therapeutics are not yet available. This narrative review aims to outline possible therapeutic strategies to ameliorate organ dysfunction caused by eGC impairment.

Unfractionated Heparin Attenuated Histone-Induced Pulmonary Syndecan-1 Degradation in Mice: a Preliminary Study on the Roles of Heparinase Pathway

Endothelial glycocalyx degradation is thought to facilitate the development of sepsis. Histone is a significant mediator in sepsis. Unfractionated heparin (UFH) possessed beneficial effects on sepsis. Thereby, this study aims to figure out whether histone can disrupt glycocalyx and to investigate the protective effect and mechanism of UFH. Male mice (C57BL/6, 8-10 weeks old, weighing 20-25 g) were randomly divided into five groups including control group, histone group, histone + UFH group, histone + heparinase (HPA) inhibitor group, and histone + UFH + HPA inhibitor group. The mice were treated with histone (50 mg/kg) via tail vein immediately after HPA (20 mg/kg) injection. UFH (400 U/kg) was injected 1h after histone administration. The other groups were injected with equal volume of sterile saline accordingly. UFH alleviated histone-induced lung injury and pulmonary edema. UFH inhibited histone-induced lung coagulation activation and inflammatory response. UFH treatment markedly inhibited pulmonary glycocalyx degradation by reducing the histone-induced decrease in the levels of lung syndecan-1 mRNA and protein. UFH downregulated histone-induced expression of HPA mRNA and protein, and thus alleviated glycocalyx degradation. UFH protects against histone-induced pulmonary glycocalyx injury partly by heparinase pathway.

Unfractionated Heparin Improves the Intestinal Microcirculation in a Canine Septic Shock Model

Background

Alterations of microcirculation are associated with organ hypoperfusion and high mortality in septic shock. This study is aimed at investigating the effects of unfractionated heparin (UFH) on intestinal microcirculatory perfusion and systemic circulation in a septic shock model.

Methods

Twenty-four beagle dogs were randomly allocated into four groups: (a) sham group: healthy controls, (b) shock group: septic shock induced by Escherichia coli, (c) basic therapy group: septic shock animals treated with antibiotics and 10 ml/kg/h saline, and (d) heparin group: septic shock animals treated with basic therapy plus UFH. Hemodynamic variables were measured within 24 h after E. coli administration. The intestinal microcirculation was simultaneously investigated with a sidestream dark-field imaging technique. Additionally, the function of vital organs was evaluated at 12 h postadministration (T12).

Results

E. coli induced a progressive septic shock in which the mean arterial pressure (MAP) decreased and lactate levels sharply increased, accompanied by deteriorated microvessel perfusion. While basic therapy partially improved the microvascular flow index and the perfused microvessel density in the jejunal villi, UFH significantly restored major microcirculation variables at T12. Physiological variables, including MAP, urine output, and lactate levels, were improved by UFH, whereas some hemodynamic indices were not affected by UFH. With respect to organ function, UFH increased the platelet count and decreased the creatinine level.

Conclusions

UFH improves microcirculatory perfusion of the small intestine independently of the changes in systemic hemodynamic variables in a canine model of septic shock, thereby improving coagulation and renal function.

The Role of Histones and Heparin in Sepsis: A Review

Septic shock with multiple organ failure is a devastating situation in clinical settings. Through the past decades, much progress has been made in the management of sepsis and its underlying pathogenesis, but a highly effective therapeutic has not been developed. Recently, macromolecules such as histones have been targeted in the treatment of sepsis. Histones primarily function as chromosomal organizers to pack DNA and regulate its transcription through epigenetic mechanisms. However, a growing body of research has shown that histone family members can also exert cellular toxicity once they relocate from the nucleus into the extracellular space. Heparin, a commonly used anti-coagulant, has been shown to possess life-saving capabilities for septic patients, but the potential interplay between heparin and extracellular histones has not been investigated. In this review, we summarize the pathogenic roles of extracellular histones and the therapeutic roles of heparin in the development and management of sepsis and septic shock.

Unfractionated heparin attenuates endothelial barrier dysfunction via the phosphatidylinositol-3 kinase/serine/threonine kinase/nuclear factor kappa-B pathway

Background

Vascular endothelial dysfunction is considered a key pathophysiologic process for the development of acute lung injury. In this study, we aimed at investigating the effects of unfractionated heparin (UFH) on the lipopolysaccharide (LPS)-induced changes of vascular endothelial-cadherin (VE-cadherin) and the potential underlying mechanisms.

Methods

Male C57BL/6 J mice were randomized into three groups: vehicle, LPS, and LPS + UFH groups. Intraperitoneal injection of 30 mg/kg LPS was used to induce sepsis. Mice in the LPS + UFH group received subcutaneous injection of 8 U UFH 0.5 h before LPS injection. The lung tissue of the mice was collected for assessing lung injury by measuring the lung wet/dry (W/D) weight ratio and observing histological changes. Human pulmonary microvascular endothelial cells (HPMECs) were cultured and used to analyze the effects of UFH on LPS- or tumor necrosis factor-alpha (TNF-α)-induced vascular hyperpermeability, membrane expression of VE-cadherin, p120-catenin, and phosphorylated myosin light chain (p-MLC), and F-actin remodeling, and on the LPS-induced activation of the phosphatidylinositol-3 kinase (PI3K)/serine/threonine kinase (Akt)/nuclear factor kappa-B (NF-κB) signaling pathway.

Results

In vivo, UFH pretreatment significantly attenuated LPS-induced pulmonary histopathological changes (neutrophil infiltration and erythrocyte effusion, alveolus pulmonis collapse, and thicker septum), decreased the lung W/D, and increased protein concentration (LPS vs. LPS + UFH: 0.57 ± 0.04 vs. 0.32 ± 0.04 mg/mL, P = 0.0092), total cell count (LPS vs. LPS + UFH: 9.57 ± 1.23 vs. 3.65 ± 0.78 × 10⁵/mL, P = 0.0155), polymorphonuclear neutrophil percentage (LPS vs. LPS + UFH: 88.05% ± 2.88% vs. 22.20% ± 3.92%, P = 0.0002), and TNF-α (460.33 ± 23.48 vs. 189.33 ± 14.19 pg/mL, P = 0.0006) in the bronchoalveolar lavage fluid. In vitro, UFH pre-treatment prevented the LPS-induced decrease in the membrane expression of VE-cadherin (LPS vs. LPS + UFH: 0.368 ± 0.044 vs. 0.716 ± 0.064, P = 0.0114) and p120-catenin (LPS vs. LPS + UFH: 0.208 ± 0.018 vs. 0.924 ± 0.092, P = 0.0016), and the LPS-induced increase in the expression of p-MLC (LPS vs. LPS + UFH: 0.972 ± 0.092 vs. 0.293 ± 0.025, P = 0.0021). Furthermore, UFH attenuated LPS- and TNF-α-induced hyperpermeability of HPMECs (LPS vs. LPS + UFH: 8.90 ± 0.66 vs. 15.84 ± 1.09 Ω·cm², P = 0.0056; TNF-α vs. TNF-α + UFH: 11.28 ± 0.64 vs. 18.15 ± 0.98 Ω·cm², P = 0.0042) and F-actin remodeling (LPS vs. LPS + UFH: 56.25 ± 1.51 vs. 39.70 ± 1.98, P = 0.0027; TNF-α vs. TNF-α + UFH: 55.42 ± 1.42 vs. 36.51 ± 1.20, P = 0.0005) in vitro. Additionally, UFH decreased the phosphorylation of Akt (LPS vs. LPS + UFH: 0.977 ± 0.081 vs. 0.466 ± 0.035, P = 0.0045) and I kappa B Kinase (IKK) (LPS vs. LPS + UFH: 1.023 ± 0.070 vs. 0.578 ± 0.044, P = 0.0060), and the nuclear translocation of NF-κB (LPS vs. LPS + UFH: 1.003 ± 0.077 vs. 0.503 ± 0.065, P = 0.0078) in HPMECs, which was similar to the effect of the PI3K inhibitor, wortmannin.

Conclusions

The protective effect of UFH against LPS-induced pulmonary endothelial barrier dysfunction involves VE-cadherin stabilization and PI3K/Akt/NF-κB signaling.

Unfractionated heparin inhibits histone-mediated coagulation activation and thrombosis in mice

INTRODUCTION

Histones play pivotal roles in the pathophysiology of sepsis. Different studies have reported that unfractionated heparin (UFH) can improve histone-mediated organ dysfunction. However, in such studies, UFH was usually pretreated or injected with histones concurrently, which was obviously inconsistent with clinical practice. Therefore, this study aimed to figure out whether UFH can inhibit histone-induced coagulation activation and thrombosis when histones have caused coagulation disorder already.

METHODS

Male C57/BL6 mice of average weight ~22 g were randomly divided into three groups. The histone group was injected with histones 50 mg/kg through the tail vein. The histone + UFH group was injected with UFH (400 U/kg) through the tail vein 1 h or 6 h after the induction of histones. The control group was injected with equal volume of sterile saline. The lungs were harvested 3 h after UFH administration. In survival studies, mice were treated with UFH (800 U/kg, n = 10) or sterile saline (n = 10) intravenously after histones (75 mg/kg) injection and observed for 7 days.

RESULTS

1) UFH improved survival rate in mice injected with lethal doses of histones; 2) UFH alleviated histone-induced lung injury and pulmonary edema; 3) UFH improved histone-induced endothelial cell injury; 4) UFH improved histone-mediated high expression of TF, PAI-1, fibrinogen and low expression of TM.

CONCLUSION

UFH can effectively attenuate histone-induced lung injury, coagulation activation and thrombosis.

Unfractionated heparin attenuates histone-mediated cytotoxicity in vitro and prevents intestinal microcirculatory dysfunction in histone-infused rats

BACKGROUND

Extracellular histones are major mediators of organ dysfunction and death in sepsis, and they may cause microcirculatory dysfunction. Heparins have beneficial effects in sepsis and have been reported to bind to histones and neutralize their cytotoxicity. The aim of this study was to investigate the impact of histones on intestinal microcirculation and the intestinal endothelium and to discuss the protective effect of unfractionated heparin (UFH) on the endothelial cytotoxicity and microcirculatory dysfunction induced by histones.

METHODS

Anesthetized rats were infused with 30 mg/kg calf thymus histones, and UFH was administered intravenously at a concentration of 100 IU/kg per hour. The intestinal microcirculation was visualized and measured with incident dark field microscope. Plasma von Willebrand factor (vWF) and soluble thrombomodulin were detected, and structural changes in the rat intestinal microvascular endothelium were examined. The effects of histones and UFH on cell survival rates, vWF release and calcium influx were investigated in human intestinal microvascular endothelial cells (HIMECs).

RESULTS

Histone infusion caused severe intestinal microcirculatory dysfunction in the absence of obvious hemodynamic changes, and UFH protected intestinal microcirculation in histone-infused rats. Concentrations of the plasma endothelial injury markers vWF and soluble thrombomodulin were elevated, and structural abnormalities were found in the intestinal microvascular endothelium in the histone-infused rats. These events were attenuated by UFH. In vitro, UFH significantly reduced the histone-induced cytotoxicity of HIMECs, reduced the release of vWF from the cytoplasm into the culture medium, and inhibited calcium influx into HIMECs.

CONCLUSION

Histones induce intestinal microcirculatory dysfunction followed by direct injury to the endothelial cells; UFH protects the intestinal microcirculation partly by antagonizing the endothelial toxicity of histones.

Unfractionated heparin ameliorates pulmonary microvascular endothelial barrier dysfunction via microtubule stabilization in acute lung injury

Background

Endothelial barrier dysfunction is central to the pathogenesis of sepsis-associated acute lung injury (ALI). Microtubule (MT) dynamics in vascular endothelium are crucial for the regulation of endothelial barrier function. Unfractionated heparin (UFH) possesses various biological activities, such as anti-inflammatory activity and endothelial barrier protection during sepsis.

Methods

Here, we investigated the effects and underlying mechanisms of UFH on lipopolysaccharide (LPS)-induced endothelial barrier dysfunction. C57BL/6 J mice were randomized into vehicle, UFH, LPS and LPS + UFH groups. Intraperitoneal injection of 30 mg/kg LPS was used to induce sepsis. Mice in the LPS + UFH group received intravenous UFH 0.5 h prior to LPS injection. Human pulmonary microvascular endothelial cells (HPMECs) were cultured for analyzing the effects of UFH on LPS-induced and nocodazole-induced hyperpermeability, F-actin remodeling, and LPS-induced p38 MAPK activation.

Results

UFH pretreatment significantly attenuated LPS-induced pulmonary histopathological changes, and increased the lung W/D ratio and Evans blue accumulation in vivo. Both in vivo and in vitro studies showed that UFH pretreatment blocked the LPS-induced increase in guanine nucleotide exchange factor (GEF-H1) expression and myosin phosphatase target subunit 1 (MYPT1) phosphorylation, and microtubule (MT) disassembly in LPS-induced ALI mouse model and human pulmonary microvascular endothelial cells (HPMECs). These results suggested that UFH ameliorated LPS-induced endothelial barrier dysfunction by inhibiting MT disassembly and GEF-H1 expression. In addition, UFH attenuated LPS-induced hyperpermeability of HPMECs and F-actin remodeling. In vitro, UFH pretreatment inhibited LPS-induced increase in monomeric tubulin expression and decrease in tubulin polymerization and acetylation. Meanwhile, UFH ameliorates nocodazole-induced MTs disassembly and endothelial barrier dysfunction.Additionally, UFH decreased p38 phosphorylation and activation, which was similar to the effect of the p38 MAPK inhibitor, SB203580.

Conclusions

UFH exert its protective effects on pulmonary microvascular endothelial barrier dysfunction via microtubule stabilization and is associated with the p38 MAPK pathway.

How I treat disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC) is a condition characterized by systemic activation of coagulation, potentially leading to thrombotic obstruction of small and midsize vessels, thereby contributing to organ dysfunction. At the same time, ongoing consumption of platelets and coagulation proteins results in thrombocytopenia and low concentrations of clotting factors, which may cause profuse hemorrhagic complications. DIC is always secondary to an underlying condition, such as severe infections, solid or hematologic malignancies, trauma, or obstetric calamities. A reliable diagnosis of DIC can be made through simple scoring algorithms based on readily available routine hemostatic parameters. The cornerstone of supportive treatment of this coagulopathy is management of the underlying condition. Additionally, administration of heparin may be useful, and restoration of physiological anticoagulants has been suggested, but has not been proven successful in improving clinically relevant outcomes so far. In patients with major bleeding or at risk for hemorrhagic complications, administration of platelet concentrates, plasma, or coagulation factor concentrates should be considered.

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.

Unfractionated heparin protects the protein C system against lipopolysaccharide-induced damage in vivo and in vitro

Activation of protein C is greatly enhanced by the presence of thrombomodulin (TM) and endothelial protein C receptor (EPCR) on the endothelial surface. Impairment of the anticoagulant protein C system occurs during endotoxemia and contributes to sepsis-associated hypercoagulability. Previous studies have demonstrated that unfractionated heparin (UFH) can attenuate coagulation in endotoxemic mice. However, whether UFH has an effect on the protein C system remains to be elucidated. The current study evaluated the therapeutic effect of UFH on the protein C system in a mouse model of lipopolysaccharide (LPS)-induced sepsis, and further investigated the effect of UFH on the expression of TM and EPCR in vitro using human umbilical vein endothelial cells (HUVECs). The in vivo data indicated that UFH preconditioning attenuated the decline in circulating activated protein C following LPS administration, and also reduced LPS-induced shedding of TM and EPCR. In HUVECs, LPS stimulation led to the downregulation of TM and EPCR expression, and UFH dose-dependently restored the mRNA and protein levels of TM and EPCR. In addition, UFH inhibited the LPS-induced activation of mitogen-activated protein kinase 14, proto-oncogene tyrosine-protein kinase Src and nuclear factor κB signaling in HUVECs. In summary, these results suggest that UFH has a protective effect on the protein C system during sepsis. Thus, UFH may be a candidate therapeutic agent for the treatment of patients with sepsis.

The role of heparin in sepsis: much more than just an anticoagulant

Despite progress in antibiotic treatment, mechanical ventilation, fluid resuscitation and blood glucose maintenance, sepsis remains a cause of high mortality in the intensive care unit to date, there are no proven treatment strategies for the routine management of septic patients. The extensive interaction between inflammation and coagulation contributes to the basic pathophysiology of sepsis. Thus, the agents that attenuate the activation of both inflammation and coagulation may improve the outcome in sepsis. Apart from the well-known anticoagulant effects of heparin, it also possesses various immunomodulatory properties and protects glycocalyx from shedding. Hence, heparin seems to be such an agent. Immunothrombosis plays an important role in early host defence against bacterial dissemination, thus the proper timing for anticoagulant therapy should be determined. We review the available experimental and clinical data supporting the use of heparin in sepsis. At this time the use of heparin in the treatment of sepsis is conflicting. Future trials of heparin therapy for sepsis should concentrate on the very severely ill patients, in whom benefit is most likely to be demonstrated.

Heparanase Mediates Intestinal Inflammation and Injury in a Mouse Model of Sepsis

Heparanase, a heparan sulfate (HS)-specific endoglycosidase, plays an important role in inflammation and mediates acute pulmonary and renal injuries during sepsis. To explore its role in septic intestinal injury, a non-anticoagulant heparanase inhibitor, N-desulfated/re- N-acetylated heparin (NAH), was administrated to a mouse sepsis model induced by cecal ligation and puncture (CLP). Immunohistochemical staining revealed massive shedding of HS from the intestinal mucosal surfaces after CLP, and effective inhibition of heparanase by NAH was confirmed by markedly reduced HS shedding. Following CLP, intestinal expression of heparanase was increased, whereas pretreatment with NAH reduced the sepsis-induced upregulation of heparanase expression. Meanwhile, CLP led to shedding of syndecan-1 and upregulated expression of proteases such as matrix metalloprotease-9 and urokinase-type plasminogen activator in the intestine, whereas NAH markedly suppressed syndecan-1 shedding and protease upregulation following CLP. In addition, pretreatment with NAH attenuated intestinal injury, inhibited neutrophil infiltration and suppressed the production of inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, and interleukin-6) in the intestine during sepsis, and it also significantly reduced the elevation of inflammatory cytokines in the serum 24 hr after CLP. Our findings demonstrate that the activation of intestinal heparanase contributes to intestinal injury during early sepsis by facilitating the destruction of mucosal epithelial glycocalyx and promoting inflammatory responses.

Coagulation factor XI vaccination: an alternative strategy to prevent thrombosis

Essentials Coagulation Factor (F) XI is a safe target for the development of antithrombotics. We designed an antigen comprising the human FXI catalytic domain and diphtheria toxin T domain. Antigen immunization reduced plasma FXI activity by 54% and prevented thrombosis in mice. FXI vaccination can serve as an effective strategy for thrombosis prevention.

SUMMARY

Background Coagulation factor XI serves as a signal amplifier in the intrinsic coagulation pathway. Blockade of FXI by mAbs or small-molecule inhibitors inhibits thrombosis without causing severe bleeding, which is an inherent risk of currently available antithrombotic agents. Objectives To design an FXI vaccine and assess its efficacy in inhibiting FXI activity and preventing thrombosis. Methods An FXI antigen was generated by fusing the catalytic domain of human FXI to the C-terminus of the transmembrane domain of diphtheria toxin. The anti-FXI antibody response, plasma FXI activity and antithrombotic efficacy in mice immunized with the FXI antigen were examined. Results The antigen elicited a significant antibody response against mouse FXI, and reduced the plasma FXI activity by 54.0% in mice. FXI vaccination markedly reduced the levels of coagulation and inflammation in a mouse model of inferior vena cava stenosis. Significant protective effects were also observed in mouse models of venous thrombosis and pulmonary embolism. Conclusions Our data demonstrate that FXI vaccination can serve as an effective strategy for thrombosis prevention.

Rho-kinase inhibitor treatment prevents pulmonary inflammation and coagulation in lipopolysaccharide-induced lung injury

INTRODUCTION

In the pathogenesis of sepsis-induced acute lung injury (ALI), the crosstalk between inflammation and coagulation plays a pivotal role. The aim of this study was to investigate the role of Rho kinase (ROCK) inhibitor in alleviating pulmonary inflammation and coagulation in lipopolysaccharide (LPS)-induced acute lung injury (ALI) models.

METHODS

In the in vivo study, mice were randomized to four different groups: Control, Y-27632 (Y), LPS, and LPS+Y-27632 (LPS+Y). ALI was induced by intranasally administering LPS (10μg in 50μL PBS). Y-27632 (10mg/kg body weight,) was injected intraperitoneally at 18h and 1h before LPS challenge. Mice were euthanized at 3h or 8h post LPS challenge (N=8 per group). In the in vitro study, human pulmonary microvascular endothelial cells (HPMECs) were incubated with LPS alone (1μg/mL) or in combination with 10μM Y-27632 or 50μM BAY11-7082. Cells were pretreated with the inhibitors 30min before exposure to LPS. Three hours later, cells were isolated for subsequent analysis.

RESULTS

The myeloperoxidase (MPO) activity and fibrinogen deposits in the lung tissue significantly decreased and the lung damage in ALI mouse was attenuated. Pretreatment with Y-27632 markedly reduced the LPS-induced expression of interleukins 1β and 6, and the activation of nuclear factor (NF)-κB. Furthermore, ROCK inhibitor treatment antagonized the expression of tissue factor (TF) and plasminogen activator inhibitor (PAI)-1 in lung tissue and HPMECs.

CONCLUSIONS

ROCK inhibition protects against the endotoxin-induced pulmonary inflammation and coagulation via NF-kappaB pathway modulation.

Heparin-binding protein is important for vascular leak in sepsis

BACKGROUND

Elevated plasma levels of heparin-binding protein (HBP) are associated with risk of organ dysfunction and mortality in sepsis, but little is known about causality and mechanisms of action of HBP. The objective of the present study was to test the hypothesis that HBP is a key mediator of the increased endothelial permeability observed in sepsis and to test potential treatments that inhibit HBP-induced increases in permeability.

METHODS

Association between HBP at admission with clinical signs of increased permeability was investigated in 341 patients with septic shock. Mechanisms of action and potential treatment strategies were investigated in cultured human endothelial cells and in mice.

RESULTS

Following adjustment for comorbidities and Acute Physiology and Chronic Health Evaluation (APACHE) II, plasma HBP concentrations were weakly associated with fluid overload during the first 4 days of septic shock and the degree of hypoxemia (PaO₂/FiO₂) as measures of increased systemic and lung permeability, respectively. In mice, intravenous injection of recombinant human HBP induced a lung injury similar to that observed after lipopolysaccharide injection. HBP increased permeability of vascular endothelial cell monolayers in vitro, and enzymatic removal of luminal cell surface glycosaminoglycans (GAGs) using heparinase III and chondroitinase ABC abolished this effect. Similarly, unfractionated heparins and low molecular weight heparins counteracted permeability increased by HBP in vitro. Intracellular, selective inhibition of protein kinase C (PKC) and Rho-kinase pathways reversed HBP-mediated permeability effects.

CONCLUSIONS

HBP is a potential mediator of sepsis-induced acute lung injury through enhanced endothelial permeability. HBP increases permeability through an interaction with luminal GAGs and activation of the PKC and Rho-kinase pathways. Heparins are potential inhibitors of HBP-induced increases in permeability.

Near-Infrared Emitting PbS Quantum Dots for in Vivo Fluorescence Imaging of the Thrombotic State in Septic Mouse Brain

Near-infrared (NIR) fluorescent imaging is a powerful tool for the non-invasive visualization of the inner structure of living organisms. Recently, NIR fluorescence imaging at 1000–1400 nm (second optical window) has been shown to offer better spatial resolution compared with conventional NIR fluorescence imaging at 700–900 nm (first optical window). Here we report lead sulfide (PbS) quantum dots (QDs) and their use for in vivo NIR fluorescence imaging of cerebral venous thrombosis in septic mice. Highly fluorescent PbS QDs with a 1100 nm emission peak (QD1100) were prepared from lead acetate and hexamethyldisilathiane, and the surface of QD1100 was coated with mercaptoundecanoic acid so as to be soluble in water. NIR fluorescence imaging of the cerebral vessels of living mice was performed after intravascular injection (200–300 μL) of QD1100 (3 μM) from a caudal vein. By detecting the NIR fluorescence of QD1100, we achieved non-invasive NIR fluorescence imaging of cerebral blood vessels through the scalp and skull. We also achieved NIR fluorescence imaging of cerebral venous thrombosis in septic mice induced by the administration of lipopolysaccharide (LPS). From the NIR fluorescence imaging, we found that the number of thrombi in septic mice was significantly increased by the administration of LPS. The formation of thrombi in cerebral blood vessels in septic mice was confirmed by enzyme-linked immunosorbent assay (ELISA). We also found that the number of thrombi significantly decreased after the administration of heparin, an inhibitor of blood coagulation. These results show that NIR fluorescence imaging with QD1100 is useful for the evaluation of the pathological state of cerebral blood vessels in septic mice.

Heparin inhibits lipopolysaccharide-induced inflammation via inducing caveolin-1 and activating the p38/mitogen-activated protein kinase pathway in murine peritoneal macrophages

Heparin is a soluble glycosaminoglycan largely used as an anti-coagulant drug and with well known anti‑inflammatory effects. However, heparin is currently not used as an anti‑inflammatory agent in the clinic due to a risk of bleeding as well as its complex mechanism of action. The underlying mechanism of the anti‑inflammatory action of heparin and its effector targets have remained to be fully elucidated. The present study confirmed the anti‑inflammatory effects of heparin in lipopolysaccharide (LPS)‑induced murine peritoneal macrophages through decreasing the levels of the inflammatory cytokines tumor necrosis factor alpha (TNF‑α), interleukin 6 (IL‑6), IL‑8 and IL‑1β. Caveolin‑1 participated in the anti‑inflammatory process and it was able to be induced by heparin. Transfection of small interfering RNA of caveolin‑1 into murine peritoneal macrophages attenuated the anti‑inflammatory effects of heparin. Furthermore, following caveolin‑1 silencing, the p38/mitogen‑activated protein kinase (MAPK) pathway was still able to be activated by heparin, while the extracellular signal‑regulated kinase and c‑Jun N‑terminal kinase pathways were inhibited. In conclusion, these results suggested that heparin inhibits LPS‑induced inflammation via inducing caveolin‑1 and activating the p38/MAPK pathway in murine peritoneal macrophages. Revealing the anti‑inflammatory mechanisms of heparin will aid in its development for clinical treatment in the future.

Sulfated glycans in inflammation

Sulfated glycans such as glycosaminoglycans on proteoglycans are key players in both molecular and cellular events of inflammation. They participate in leukocyte rolling along the endothelial surface of inflamed sites; chemokine regulation and its consequential functions in leukocyte guidance, migration and activation; leukocyte transendothelial migration; and structural assembly of the subendothelial basement membrane responsible to control tissue entry of cells. Due to these and other functions, exogenous sulfated glycans of various structures and origins can be used to interventionally down-regulate inflammation processes. In this review article, discussion is given primarily on the anti-inflammatory functions of mammalian heparins, heparan sulfate, chondroitin sulfate, dermatan sulfate and related compounds as well as the holothurian fucosylated chondroitin sulfate and the brown algal fucoidans. Understanding the underlying mechanisms of action of these sulfated glycans in inflammation, helps research programs involved in developing new carbohydrate-based drugs aimed to combat acute and chronic inflammatory disorders.

Heparin inhibits the inflammatory response induced by LPS and HMGB1 by blocking the binding of HMGB1 to the surface of macrophages

High mobility group box 1 protein (HMGB1), a nuclear non-histone DNA-binding protein, is secreted extracellularly during inflammation and is a late mediator of inflammatory responses. The pro-inflammatory activity of recombinant HMGB1 proteins is dependent upon the formation of complexes with other mediators, such as lipopolysaccharide (LPS). This study investigated the influence of heparin on LPS+HMGB1-mediated inflammatory responses in cultured macrophages and a murine sepsis model. HMGB1 promoted the phosphorylation of p38 and ERK1/2. HMGB1 enhanced the induction of the pro-inflammatory cytokine, TNF-α, by LPS in macrophages. Heparin blocked the binding of HMGB1 to the surface of macrophages, and suppressed the phosphorylation of p38 and ERK1/2, but not JNK; TNF-α secretion was also decreased. However, heparin alone did not affect LPS-induced production of TNF-α. Heparin reduced lethality in mice exposed to LPS+HMGB1. To conclude, heparin inhibited LPS-induced HMGB1-amplified inflammatory responses by blocking HMGB1 binding to macrophage surfaces. Heparin could be used therapeutically as an effective inhibitor of HMGB1-associated inflammation.

Heparin modulation on hepatic nitric oxide synthase in experimental steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is considered to be a hepatic manifestation of metabolic syndrome, and has been etiologically associated with insulin resistance (IR). The histopathology of NAFLD ranges between simple steatosis and nonalcoholic steatohepatitis (NASH), with or without fibrosis. The aim of the present study was to examine the effect of heparin on steatohepatitis and hepatic-induced nitric oxide synthase (iNOS) expression in mice. Male mice were divided into four groups, which included the normal basal diet (control), high fat (HF) diet, HF diet + heparin (treatment group) and heparin control groups. After eight weeks from the initiation of the experiment, blood was collected and livers were harvested for biochemical analysis and histological studies. Serum levels of aspartate aminotransferase, alanine aminotransferase, hepatic triglyceride (TG) and hydroxyproline, as well as the IR, superoxide anion generation and mRNA expression of the hepatic iNOS enzyme were evaluated. Liver specimens were processed for histopathological and immunohistopathological evaluation. Heparin administration decreased the levels of the liver enzymes, IR, superoxide generation, hepatic TG, hydroxyproline and iNOS expression when compared with the HF diet group. These changes were associated with an improvement in inflammation and fibrosis observed via histopathological examination. Therefore, heparin treatment attenuates hepatic injury in steatohepatitis.

Azurocidin-induced inhibition of oxygen metabolism in mitochondria is antagonized by heparin

Heparin is a potent blood anticoagulant that has been demonstrated to attenuate inflammatory responses in sepsis. Sepsis is considered to be a microcirculation-mitochondrial distress syndrome. Azurocidin (AZU), a protein with strong heparin-binding potential that induces inflammatory responses and apoptosis, has been shown to increase the permeability of endothelial cells and induce the prognosis of sepsis. However, the function of AZU in mitochondrial oxygen metabolism has yet to be reported. The aim of the present study was to investigate whether heparin exhibits an antagonistic effect on AZU-induced mitochondrial dysfunction in human umbilical vein endothelial cells (HUVECs) and to further investigate the possible underlying mechanisms. HUVECs were randomly assigned into blank control, AZU, heparin plus AZU and heparin groups. The blank control group were incubated with phosphate-buffered saline for 12 h, while the AZU group were incubated with 1 μg/ml AZU for 12 h. The heparin plus AZU group were incubated with 100 μg/ml heparin for 2 h, followed by the addition of 1 μg/ml AZU and incubation for 12 h. The heparin group were incubated with 100 μg/ml heparin for 12 h. Flow cytometry was used to determine the mitochondrial membrane potential, while electron microscopy was used to determine the mitochondrial morphology. Western blotting and quantitative polymerase chain reaction were used to determine the protein and mRNA expression levels of Cox II in the mitochondria, respectively. Western blotting was also used to evaluate the concentration of AZU in cytoplasm, along with immunofluorescence analysis. AZU was revealed to decrease the mitochondrial membrane potential, reduce cytochrome c oxidase subunit II expression and destroy the morphology of the mitochondria. Heparin exhibited an antagonistic function on these processes and inhibited the endocytosis of AZU by HUVECs. In conclusion, the results indicated that AZU inhibited the oxygen metabolic function in mitochondria, and this function was effectively antagonized by heparin via the inhibition of AZU endocytosis by HUVECs. Therefore, heparin may be a potential therapeutic agent for treating mitochondrial dysfunction in the future.

Unfractionated heparin suppresses lipopolysaccharide-induced monocyte chemoattractant protein-1 expression in human microvascular endothelial cells by blocking Krüppel-like factor 5 and nuclear factor-κB pathway

Unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH), apart from anticoagulant activities, contain a variety of biological properties such as anti-inflammatory actions possibly affecting sepsis. Chemokines are vital for promoting the movement of circulating leukocytes to the site of infection and are involved in the pathogenesis of sepsis. The purpose of this study was to investigate the effects and potential mechanisms of UFH on lipopolysaccharide (LPS)-induced chemokine production in human pulmonary microvascular endothelial cells (HPMECs). HPMECs were pretreated with UFH (0.1 U/ml and 1 U/ml), 15 min prior to stimulation with LPS (10 μg/ml). Cells were cultured under various experimental conditions for 2 h and 6 h for analysis. UFH markedly decreased LPS-induced interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1) mRNA and protein expression in HPMECs. UFH also attenuated the secretion of these chemokines in culture supernatants. In addition, UFH blocked the chemotactic activities of LPS-stimulated HPMECs supernatants on monocytes migration as expected. UFH inhibited LPS-induced Krüppel-like factor 5 (KLF-5) mRNA and protein levels. Concurrently, UFH reduced nuclear factor (NF)-κB nuclear translocation. Importantly, transfection with siRNA targeting KLF-5 reduced NF-κB activation and chemokines expression. These results demonstrate that interfering with KLF-5 mediated NF-κB activation might contribute to the inhibitory effects of chemokines and monocytes migration by UFH in LPS-stimulated HPMECs.

Different contribution of splanchnic organs to hyperlactatemia in fecal peritonitis and cardiac tamponade

Background. Changes in hepatosplanchnic lactate exchange are likely to contribute to hyperlactatemia in sepsis. We hypothesized that septic and cardiogenic shock have different effects on hepatosplanchnic lactate exchange and its contribution to hyperlactatemia. Materials and Methods. 24 anesthetized pigs were randomized to fecal peritonitis (P), cardiac tamponade (CT), and to controls (n = 8 per group). Oxygen transport and lactate exchange were calculated during 24 hours. Results. While hepatic lactate influx increased in P and in CT, hepatic lactate uptake remained unchanged in P and decreased in CT. Hepatic lactate efflux contributed 20% (P) and 33% (CT), respectively, to whole body venous efflux. Despite maintained hepatic arterial blood flow, hepatic oxygen extraction did not increase in CT. Conclusions. Whole body venous lactate efflux is of similar magnitude in hyperdynamic sepsis and in cardiogenic shock. Although jejunal mucosal pCO₂ gradients are increased, enhanced lactate production from other tissues is more relevant to the increased arterial lactate. Nevertheless, the liver fails to increase hepatic lactate extraction in response to rising hepatic lactate influx, despite maintained hepatic oxygen consumption. In cardiac tamponade, regional, extrasplanchnic lactate production is accompanied by hepatic failure to increase oxygen extraction and net hepatic lactate output, despite maintained hepatic arterial perfusion.

Bench-to-bedside review: Citrate for continuous renal replacement therapy, from science to practice

To prevent clotting in the extracorporeal circuit during continuous renal replacement therapy (CRRT) anticoagulation is required. Heparin is still the most commonly used anticoagulant. However, heparins increase the risk of bleeding, especially in critically ill patients. Evidence has accumulated that regional anticoagulation of the CRRT circuit with citrate is feasible and safe. Compared to heparin, citrate anticoagulation reduces the risk of bleeding and requirement for blood products, not only in patients with coagulopathy, but also in those without. Metabolic complications are largely prevented by the use of a strict protocol, comprehensive training and integrated citrate software. Recent studies indicate that citrate can even be used in patients with significant liver disease provided that monitoring is intensified and the dose is carefully adjusted. Since the citric acid cycle is oxygen dependent, patients at greatest risk of accumulation seem to be those with persistent lactic acidosis due to poor tissue perfusion. The use of citrate may also be associated with less inflammation due to hypocalcemia-induced suppression of intracellular signaling at the membrane and avoidance of heparin, which may have proinflammatory properties. Whether these beneficial effects increase patient survival needs to be confirmed. However, other benefits are the reason that citrate should become the first choice anticoagulant for CRRT provided that its safe use can be guaranteed.