Heparin rescues sepsis-associated acute lung injury and lethality through the suppression of inflammatory responses

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.

Pulsed Electromagnetic Field (PEMF) Treatment Reduces Lipopolysaccharide-Induced Septic Shock in Mice

Despite advances in medicine, mortality due to sepsis has not decreased. Pulsed electromagnetic field (PEMF) therapy is emerging as an alternative treatment in many inflammation-related diseases. However, there are few studies on the application of PEMF therapy to sepsis. In the current study, we examined the effect of PEMF therapy on a mouse model of lipopolysaccharide (LPS)-induced septic shock. Mice injected with LPS and treated with PEMF showed higher survival rates compared with the LPS group. The increased survival was correlated with decreased levels of pro-inflammatory cytokine mRNA expression and lower serum nitric oxide levels and nitric oxide synthase 2 mRNA expression in the liver compared with the LPS group. In the PEMF + LPS group, there was less organ damage in the liver, lungs, spleen, and kidneys compared to the LPS group. To identify potential gene targets of PEMF treatment, microarray analysis was performed, and the results showed that 136 genes were up-regulated, and 267 genes were down-regulated in the PEMF + LPS group compared to the LPS group. These results suggest that PEMF treatment can dramatically decrease septic shock through the reduction of pro-inflammatory cytokine gene expression. In a clinical setting, PEMF may provide a beneficial effect for patients with bacteria-induced sepsis and reduce septic shock-induced mortality.

LPS-induced inflammatory response and apoptosis are mediated by Fra-1 upregulation and binding to YKL-40 in A549 cells

Acute respiratory distress syndrome (ARDS) is a multifactorial syndrome that leads to increased morbidity and mortality in infants and children. The identification of novel biomarkers is critical for the treatment of ARDS. The present study aimed to investigate the effects of chitinase-3-like-1 protein (CHI3L1 or YKL-40) in an in vitro model of ARDS and to explore the potential underlying mechanisms. The in vitro model of ARDS was established in A549 alveolar epithelial type II cells, which were treated by lipopolysaccharide (LPS) to induce inflammation. Transfection was performed to alter YKL-40 expression. The mRNA and protein expression of YKL-40 was determined using reverse transcription-quantitative PCR and western blotting, respectively. Cell Counting Kit-8 and TUNEL assays were used to evaluate the cell viability and apoptosis, respectively. The production of cytokines was evaluated using specific ELISA kits. The relationship between YKL-40 and Fos-related antigen 1 (Fra-1) was verified using luciferase reporter and chromatin immunoprecipitation assays. The expression of the apoptotic proteins was detected using western blotting. The expression levels of YKL-40 and Fra-1 were increased in LPS-treated A549 cells. Higher levels of pro-inflammatory cytokines and induction of cell apoptosis were observed in LPS-treated A549 cells compared with the control. YKL-40 knockdown in LPS-treated A549 cells significantly decreased the production of pro-inflammatory cytokines and reduced cell apoptosis, whereas it concomitantly caused upregulation of Bax and downregulation of Bcl-2, cleaved caspase-3 and cleaved caspase-9. In addition, Fra-1 could directly bind to YKL-40 promoter and regulate its expression level. Overexpression of YKL-40 partly decreased the inhibitory effects of Fra-1 knockdown on the inflammatory response and induction of apoptosis. In summary, the findings from the present study indicated that Fra-1 could bind to YKL-40 and regulate its expression, whereas YKL-40 knockdown could further suppress LPS-induced inflammatory response and apoptosis in A549 cells. These data may provide novel evidence on the diagnosis and therapy of ARDS.

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.

LncRNA ZFAS1 plays a role in regulating the inflammatory responses in sepsis-induced acute lung injury via mediating miR-193a-3p

OBJECTIVE

To explore the role of lncRNA ZFAS1-mediated miR-193a-3p in the regulation of inflammatory responses in rats with sepsis-induced acute lung injury (ALI).

METHODS

Sepsis-induced ALI models were constructed by LPS induction and then injected with ZFAS1 overexpression plasmid. Thereafter, lung injury score and the W/D weight ratio were calculated. Besides, bronchoalveolar lavage fluid (BALF) was isolated from rats to perform the cell count and protein quantification, while qRT-PCR and ELISA were performed to detect the inflammatory cytokines expressions. In vitro, NR8383 cells were transfected and then treated with LPS, followed by the measurement of inflammatory cytokines, cell viability and cell apoptosis.

RESULTS

In comparison with the Control group, rats in the LPS group presented sharp increases in the W/D weight ratio and injury score of lung, total protein concentration and the count of neutrophils and macrophages in BALF. Besides, rats in LPS group also resulted in a decrease in ZFAS1 expression and increase in miR-193a-3p expression in lung tissues, with the increased pro-inflammatory cytokines. Dual luciferase reporter gene assay confirmed a target relation between miR-193a-3p and ZFAS1. As compared to the Blank group, NR8383 cells in the LPS group had up-regulated pro-inflammatory cytokines with declined cell viability and elevated cell apoptosis; and meanwhile, ZFAS1 and Bcl-2 were decreased but miR-193a-3p and Bax were increased. Overexpression of ZFAS1 could significantly improve LPS-induced ALI in vivo and in vitro with reduced levels of pro-inflammatory cytokines.

CONCLUSION

Overexpression of ZFAS1, possibly via targeting the expression of miR-193a-3p, could inhibit the apoptosis and ameliorate the inflammatory responses of ALI in sepsis.

Different signaling pathways involved in the anti-inflammatory effects of unfractionated heparin on lipopolysaccharide-stimulated human endothelial cells

Background

There is a complex interplay between inflammatory response and coagulation in sepsis. Heparin is used as a recognized anticoagulant and possesses multiple biological properties that possibly affect sepsis. This study aimed to determine the possible signaling pathways involved in the anti-inflammatory effects of unfractionated heparin (UFH) on lipopolysaccharide (LPS)-stimulated human pulmonary microvascular endothelial cells (HPMECs).

Methods

HPMECs were transfected with siRNA targeting IκB-α. Cells were treated with UFH (0.01 U/ml~ 10 U/ml) 15 min before adding LPS (10 μg/ml). We detected the markers of systemic inflammatory response. Release of interleukin (IL)-6, IL-8 were evaluated at 3 h by ELISA and at 1 h by qRT-PCR. After 1 h, nuclear factor-κB (NF-κB) as well as phosphorylated inhibitor κB-α (IκB-α), signal transducer and activator of transcription-3 (STAT3) and ERK1/2, JNK, p38 mitogen-activated protein kinase (MAPK) expressions were evaluated by Western blot. DNA binding was conducted to further prove the activation of NF-κB pathway.

Results

In HPMECs, UFH obviously inhibited LPS-stimulated production of IL-6 and IL-8, especially in 10 U/ml. UFH inhibited LPS-induced phosphorylation of IκB-α, ERK1/2, JNK, p38 MAPK and STAT3. UFH also suppressed LPS-stimulated nuclear translocation of NF-κB. Importantly, transfection with siRNA targeting IκB-α induced more obvious inflammatory response. UFH suppressed cytokines production and phosphorylation of different signaling pathways in IκB-α silencing cells.

Conclusion

These results demonstrate that UFH exerts the anti-inflammatory effects on LPS-stimulated HPMECs by different signaling pathways.

Depression of lncRNA NEAT1 Antagonizes LPS-Evoked Acute Injury and Inflammatory Response in Alveolar Epithelial Cells via HMGB1-RAGE Signaling

Sepsis-evoked acute lung injury (ALI) and its extreme manifestation, acute respiratory distress syndrome (ARDS), constitute a major cause of mortality in intensive care units. High levels of the long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) have been positively correlated with increased severity and unfavorable prognoses in patients with sepsis. Nevertheless, the function and molecular mechanism of NEAT1 in ALI remain elusive. In the current study, high levels of NEAT1 were confirmed in lipopolysaccharide- (LPS-) induced ALI mice models and in LPS-stimulated cells from the alveolar epithelial A549 cell line. Intriguingly, cessation of NEAT1 led to increased cell viability and decreased lactate dehydrogenase release, apoptosis, and caspase-3/9 activity, which conferred protection against LPS-induced injury in these cells. NEAT1 inhibition also restrained LPS-evoked transcripts and production of inflammatory cytokines IL-6, IL-1β, and TNF-α. A mechanism analysis corroborated the activation of high-mobility group box1 (HMGB1)/receptors for advanced glycation end products (RAGE) and NF-κB signaling in LPS-treated A549 cells. NEAT1 suppression reversed the activation of this pathway. Notably, reactivating HMGB1/RAGE signaling via HMGB1 overexpression blunted the anti-injury and anti-inflammation effects of NEAT1 knockdown. These findings suggest that NEAT1 may aggravate the progression of ALI and ARDS by inducing alveolar epithelial cell injury and inflammation via HMGB1/RAGE signaling, implying a promising treatment target for these conditions.

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.

PEGylated enhanced cell penetrating peptide nanoparticles for lung gene therapy

The lung remains an attractive target for the gene therapy of monogenetic diseases such as cystic fibrosis (CF). Despite over 27 clinical trials, there are still very few gene therapy vectors that have shown any improvement in lung function; highlighting the need to develop formulations with improved gene transfer potency and the desirable physiochemical characteristics for efficacious therapy. Herein, we introduce a novel cell penetrating peptide (CPP)-based non-viral vector that utilises glycosaminoglycan (GAG)-binding enhanced transduction (GET) for highly efficient gene transfer. GET peptides couple directly with DNA through electrostatic interactions to form nanoparticles (NPs). In order to adapt the GET peptide for efficient in vivo delivery, we engineered PEGylated versions of the peptide and employed a strategy to form DNA NPs with different densities of PEG coatings. We were able to identify candidate formulations (PEGylation rates ≥40%) that shielded the positively charged surface of particles, maintained colloidal stability in bronchoalveolar lavage fluid (BALF) and retained gene transfer activity in human bronchial epithelial cell lines and precision cut lung slices (PCLS) in vitro. Using multiple particle tracking (MPT) technology, we demonstrated that PEG-GET complexes were able to navigate the mucus mesh and diffuse rapidly through patient CF sputum samples ex vivo. When tested in mouse lung models in vivo, PEGylated particles demonstrated superior biodistribution, improved safety profiles and efficient gene transfer of a reporter luciferase plasmid compared to non-PEGylated complexes. Furthermore, gene expression was significantly enhanced in comparison to polyethylenimine (PEI), a non-viral gene carrier that has been widely tested in pre-clinical settings. This work describes an innovative approach that combines novel GET peptides for enhanced transfection with a tuneable PEG coating for efficacious lung gene therapy.

Prohibitin and the extracellular matrix are upregulated in murine alveolar epithelial cells with LPS‑induced acute injury

Inflammation of epithelial and endothelial cells accelerates the progress of acute lung injury (ALI), and pulmonary fibrosis is the leading cause of mortality in patients with acute respiratory distress syndrome. Interleukin‑6 (IL‑6) is a pleiotropic cytokine implicated in the pathogenesis of a number of immune‑mediated disorders, and is involved in pulmonary fibrosis. Prohibitin (PHB) is a highly conserved protein implicated in various cellular functions, including proliferation, apoptosis, tumor suppression, transcription and mitochondrial protein folding. PHB was identified to be associated with a variety of pulmonary diseases, including pulmonary fibrosis. Based on the lipopolysaccharide (LPS)‑induced cell model of ALI, the present study examined the expression of PHB and the extracellular matrix (ECM) in the process of pulmonary inflammation. MLE‑12 cells were divided into 2 groups: The control group was administered sterile PBS; the treatment group was administered 500 ng/ml LPS for 12 h. The mRNA expression of IL‑6 in the treatment group was significantly upregulated compared with the control group (P<0.05). The protein expression of IL‑6 in the treatment group was markedly increased compared with the control group (P<0.05). ECM components, including collagen‑IV and fibronectin, in the treatment group were markedly increased when compared with the control group (P<0.05). The mRNA and protein expression levels of PHB1 and PHB2 were significantly upregulated following treatment with LPS (both P<0.05). The present study identified that PHB and ECM component levels increased in the LPS‑induced ALI cell model, and further investigations may be performed to verify the detailed mechanism.

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.

Recombinant CC16 protein inhibits the production of pro-inflammatory cytokines via NF-κB and p38 MAPK pathways in LPS-activated RAW264.7 macrophages

Accumulating evidence indicates that Clara cell protein-16 (CC16) has anti-inflammatory functions, although the involved molecular pathways have not been completely elucidated. Here, we evaluated the effect of recombinant rat CC16 (rCC16) on the expression of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and IL-8 in lipopolysaccharide (LPS)-stimulated mouse macrophages (RAW264.7 cells) and explored the underlying molecular mechanisms. It was found that rCC16 inhibited LPS-induced TNF-α, IL-6, and IL-8 expression at both the messenger ribonucleicacid (mRNA) level and protein level in a concentration-dependent manner, as demonstrated by real-time reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay. Such suppressive effects were accompanied by the inhibition of transcriptional activity and the deoxyribonucleic acid binding activity of nuclear factor (NF)-κB but not activator protein (AP)-1. Western blot analysis further revealed that rCC16 inhibited the increase of nuclear NF-κB and the reduction of cytosolic NF-κB, the phosphorylation and reduction of NF-κB inhibitory protein IκBα, and the p38 mitogen-activated protein kinase (MAPK)-dependent NF-κB activation by phosphorylation at Ser276 of its p65 subunit. Furthermore, rCC16 was found to have no effect on the phosphorylation of c-Jun N-terminal kinase, c-Jun, or the nuclear translocation of c-Jun. In addition, reduction of TNF-α, IL-6, and IL-8 were reversed when the level of endogenous uteroglobin-binding protein was reduced by RNA interference in rCC16- and LPS-treated RAW264.7 cells. Our data suggest that rCC16 suppresses LPS-mediated inflammatory mediator TNF-α, IL-6, and IL-8 production by inactivating NF-κB and p38 MAPK but not AP-1 in RAW264.7 cells.

Protective effect of TM6 on LPS-induced acute lung injury in mice

Acute lung injury (ALI) is an acute failure of the respiratory system for which effective treatment is urgently necessary. Previous studies found that several peptides potently inhibited the production of cytokines induced by lipopolysaccharide (LPS). In this study, we synthetized a cell-permeable TIR domain-derived decoy peptide (TM6) and examined its substance for the ability to inhibit TLR signaling in the model of ALI induced by LPS. We demonstrated that TM6 (2.5, 5 and 10 nmol/g) alleviated the histological changes in the lung tissues as well as myeloperoxtidase (MPO) activity, lung W/D ratio, the production of TNF-α, IL-1β and IL-6 induced by LPS. Furthermore, the numbers of total cells, neutrophils and macrophages in the BALF were suppressed by TM6. In vitro, TM6 (5, 10 and 20 µM) inhibited the production of TNF-α, IL-1β and IL-6 in LPS-stimulated alveolar macrophages. Moreover, the activation of Nuclear factor-kappaB (NF-κB) and Mitogen activated protein kinases (MAPK) signaling pathways induced by LPS were also inhibited by TM6. Collectively, our results suggested that TM6 was an effective inhibitor of ALI induced by LPS, and this peptide may very well serve as a future treatment for ALI.

Circulating histones are major mediators of systemic inflammation and cellular injury in patients with acute liver failure

Acute liver failure (ALF) is a life-threatening systemic disorder. Here we investigated the impact of circulating histones, recently identified inflammatory mediators, on systemic inflammation and liver injury in murine models and patients with ALF. We analyzed histone levels in blood samples from 62 patients with ALF, 60 patients with chronic liver disease, and 30 healthy volunteers. We incubated patients' sera with human L02 hepatocytes and monocytic U937 cells to assess cellular damage and cytokine production. d-galactosamine plus lipopolysaccharide (GalN/LPS), concanavalin A (ConA), and acetaminophen (APAP) were given to C57BL/6N mice to induce liver injury, respectively, and the pathogenic role of circulating histones was studied. Besides, the protective effect of nonanticoagulant heparin, which can bind histones, was evaluated with in vivo and ex vivo investigations. We observed that circulating histones were significantly increased in patients with ALF, and correlated with disease severity and mortality. Significant systemic inflammation was also pronounced in ALF patients, which were associated with histone levels. ALF patients' sera induced significant L02 cell death and stimulated U937 cells to produce cytokines, which were abrogated by nonanticoagulant heparin. Furthermore, circulating histones were all released remarkably in GalN/LPS, ConA, and APAP-treated mice, and associated with high levels of inflammatory cytokines. Heparin reduced systemic inflammation and liver damage in mice, suggesting that it could interfere with histone-associated liver injury. Collectively, these findings demonstrate that circulating histones are critical mediators of systemic inflammation and cellular damage in ALF, which may be potentially translatable for clinical use.

Effects of atorvastatin combined with low-molecular-weight heparin on plasma inflammatory cytokine level and pulmonary pathophysiology of rats with sepsis

The aim of the present study was to investigate the effect of atorvastatin combined with low-molecular-weight heparin (LMWH) on plasma early inflammatory cytokine levels as well as pulmonary pathophysiology of rats with sepsis. A total of 122 rats were randomly divided into five groups including the sham operation group (n=10), CLP group (n=10), atorvastatin group (n=34, 20 mg/kg/day), LMWH group (n=34, 100 IU/kg/day), and atorvastatin combined with LMWH group (n=34). Blood samples from 6 rats in each group were collected to detect TNF-α, IL-1β and HMGB1 concentration in plasma by linked immunosorbent assay at baseline and postoperatively at 4, 8, 12 and 24 h. Pulmonary pathophysiology was observed postoperatively at 24 h. The remaining 10 rats in each group were used to calculate the 7-day cumulative mortality rate. Compared to the sham operation group, the scores in CLP were greater than those of the sham operation group (P<0.05). Compared to the CLP group, the sepsis severity scores of the atorvastatin, LMWH, and atorvastatin combined with LMWH groups decreased gradually. Significant difference was detected in the four groups (P<0.05 0.01). Compared to the sham operation group, at 4, 8, 12 and 24 h, the TNF-α, IL-1β and HMGB1 levels in plasma in CLP increased significantly (P<0.01). Compared to the CLP group, the TNF-α, IL-1β and HMGB1 levels of plasma in other groups decreased gradually, and there was a significant difference in the four groups (P<0.01). At 24 h post operation, compared to the sham operation group, the damage of pulmonary pathophysiology in CLP was more severe. Compared to the CLP group, the damage of pulmonary pathophysiology in other groups was slight. Compared to the CLP group, the 7-day cumulative mortality rate in other groups decreased significantly (P<0.05). In conclusion, atorvastatin, combined with LMWH can decrease sepsis severity, plasma inflammatory cytokine levels, pulmonary pathophysiology, and the 7-day cumulative mortality rate. Atorvastatin, and LMWH may therefore be useful for the treatment of sepsis due to its ability to inhibit the release of TNF-α, IL-1β and HMGB1 in septic rats.

Delivery of the high-mobility group box 1 box A peptide using heparin in the acute lung injury animal models

In this study, the efficacy of the high-mobility group box-1 box A (HMGB1A)/heparin complex was evaluated for the treatment of acute lung injury (ALI). HMGB1A is an antagonist against wild-type high-mobility group box-1 (wtHMGB1), a pro-inflammatory cytokine that is involved in ALIs. HMGB1A has positive charges and can be captured in the mucus layer after intratracheal administration. To enhance the delivery and therapeutic efficiency of HMGB1A, the HMGB1A/heparin complex was produced using electrostatic interactions, with the expectation that the nano-sized complex with a negative surface charge could efficiently penetrate the mucus layer. Additionally, heparin itself had an anti-inflammatory effect. Complex formation with HMGB1A and heparin was confirmed by atomic force microscopy. The particle size and surface charge of the HMGB1A/heparin complex at a 1:1 weight ratio were 113nm and -25mV, respectively. Intratracheal administration of the complex was performed into an ALI animal model. The results showed that the HMGB1A/heparin complex reduced pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β, more effectively than HMGB1A or heparin alone. Hematoxylin and eosin staining confirmed the decreased inflammatory reaction in the lungs after delivery of the HMGB1A/heparin complex. In conclusion, the HMGB1A/heparin complex might be useful to treat ALI.

Coagulation abnormalities of sickle cell disease: Relationship with clinical outcomes and the effect of disease modifying therapies

Sickle cell disease (SCD) is a hypercoagulable state. Patients exhibit increased platelet activation, high plasma levels of markers of thrombin generation, depletion of natural anticoagulant proteins, abnormal activation of the fibrinolytic system, and increased tissue factor expression, even in the non-crisis "steady state." Furthermore, SCD is characterized by an increased risk of thrombotic complications. The pathogenesis of coagulation activation in SCD appears to be multi-factorial, with contributions from ischemia-reperfusion injury and inflammation, hemolysis and nitric oxide deficiency, and increased sickle RBC phosphatidylserine expression. Recent studies in animal models suggest that activation of coagulation may contribute to the pathogenesis of SCD, but the data on the contribution of coagulation and platelet activation to SCD-related complications in humans are limited. Clinical trials of new generations of anticoagulants and antiplatelet agents, using a variety of clinical endpoints are warranted.

Blocking NAD(+)/CD38/cADPR/Ca(2+) pathway in sepsis prevents organ damage

BACKGROUND

Although the nicotinamide adenine dinucleotide (NAD(+))/CD38/cyclic ADP ribose (cADPR)/Ca(2+) signaling pathway has been shown to regulate intracellular calcium homeostasis and functions in multiple inflammatory processes, its role in sepsis remains unknown. The aim of this study was to determine whether the NAD(+)/CD38/cADPR/Ca(2+) signaling pathway is activated during sepsis and whether an inhibitor of this pathway, 8-Br-cADPR, protects the organs from sepsis-induced damage.

MATERIALS AND METHODS

Male Sprague-Dawley rats were subjected to cecal ligation and puncture (CLP) or sham laparotomies. NAD(+), cADPR, CD38, and intracellular Ca(2+) levels were measured in the hearts, livers, and kidneys of septic rats at 0, 6, 12, 24, and 48 h after CLP surgery. Rats were also divided into sham, CLP, and CLP+8-Br-cADPR groups, and the hearts, livers, and kidneys were hematoxylin-eosin-stained and assayed for malondialdehyde and superoxide dismutase activities.

RESULTS

NAD(+), cADPR, CD38, and intracellular Ca(2+) levels increased in the hearts, livers, and kidneys of septic rats as early as 6-24 h after CLP surgery. Treatment with 8-Br-cADPR inhibited sepsis-induced intracellular Ca(2+) mobilization, attenuated tissue injury, reduced malondialdehyde levels, and increased superoxide dismutase activity in septic rats.

CONCLUSIONS

The NAD(+)/CD38/cADPR/Ca(2+) signaling pathway was activated during sepsis in the CLP rat model. Blocking this pathway with 8-Br-cADPR protected hearts, livers, and kidneys from sepsis-induced damage.

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.

Recombinant rat CC16 protein inhibits LPS-induced MMP-9 expression via NF-κB pathway in rat tracheal epithelial cells

Clara cell protein (CC16) is a well-known anti-inflammatory protein secreted by the epithelial Clara cells of the airways. It is involved in the development of airway inflammatory diseases such as chronic obstructive pulmonary disease and asthma. Previous studies suggest that CC16 gene transfer suppresses expression of interleukin (IL)-8 in bronchial epithelial cells. However, its role in the function of these cells during inflammation is not well understood. In this study, we evaluated the effect of CC16 on the expression of matrix metalloproteinase (MMP)-9 in lipopolysaccharide (LPS)-stimulated rat tracheal epithelial cells and its underlying molecular mechanisms. We generated recombinant rat CC16 protein (rCC16) which was bioactive in inhibiting the activity of phospholipase A2. rCC16 inhibited LPS-induced MMP-9 expression at both mRNA and protein levels in a concentration-dependent (0-2 µg/mL) manner, as demonstrated by real time RT-PCR, ELISA, and zymography assays. Gene transcription and DNA binding studies demonstrated that rCC16 suppressed LPS-induced NF-κB activation and its binding of gene promoters as identified by luciferase reporter and gel mobility shift assays, respectively. Western blotting and immunofluorescence staining analyses further revealed that rCC16 concentration dependently inhibited the effects of LPS on nuclear increase and cytosol reduction of NF-κB, on the phosphorylation and reduction of NF-κB inhibitory IκBα, and on p38 MAPK-dependent NF-κB activation by phosphorylation at Ser276 of its p65 subunit. These data indicate that inhibition of LPS-mediated NF-κB activation by rCC16 involves both translocation- and phosphorylation-dependent signaling pathways. When the tracheal epithelial cells were pretreated with chlorpromazine, an inhibitor of clathrin-mediated endocytosis, cellular uptake of rCC16 and its inhibition of LPS-induced NF-κB nuclear translocation and also MMP-9 production were significantly abolished. Taken together, our data suggest that clathrin-mediated uptake of rCC16 suppresses LPS-mediated inflammatory MMP-9 production through inactivation of NF-κB and p38 MAPK pathways in tracheal epithelial cells.

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.

Xuebijing exerts protective effects on lung permeability leakage and lung injury by upregulating Toll-interacting protein expression in rats with sepsis

Xuebijing (XBJ) is a type of traditional Tibetan medicine, and previous pharmacological studies have shown that the ethanol extract is derived from Chuanxiong, Chishao, Danshen and Honghua. Chuanxiong, Chishao, Danshen and Honghua possesses potent anti-inflammatory activity, and has been used in the treatment of inflammatory infectious diseases. In the present study, we investigated the effects of XBJ on pulmonary permeability and lung injury in cecal ligation and puncture (CLP)-induced sepsis in rats. A CLP sepsis model was established for the control and treatment groups, respectively. Approximately 2 h prior to surgery, an amount of 100 mg/kg XBJ injection was administered to the treatment group. Reverse transcription polymerase chain reaction (PT-PCR) and western blot analysis were used to examine the expression of Toll-interacting protein (Tollip), interleukin-1 receptor-associated kinase 1 (IRAK1), Toll-like receptor 4 (TLR4), nuclear factor-κB65 (NF-κB65) and TNF receptor-associated factor 6 (TRAF6) in lung tissue. ELISA was applied to detect changes of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 (IL-1), interleukin-4 (IL-4) and interleukin-10 (IL-10) levels in bronchoalveolar lavage (BAL) fluid, and intercellular adhesion molecule 1 (ICAM-1) and von Willebrand factor (vWF) in serum. The number of neutrophils, albumin and total cells in the BAL fluid were measured. For histological analysis, hematoxylin and eosin (H&E) stains were evaluated. Lung permeability, the wet/dry weight ratio (W/D) and the lung pathology score were determined following the induction of ALI by CLP for 24 h. The results demonstrated that XBJ upregulated Tollip expression and blocked the activity of IRAK1, TLR4, NF-κβ65 and TRAF6. Additionally, the number of neutrophils and total cells were significantly decreased in the XBJ group compared to that in the control group. Lung permeability, the wet/dry weight ratio (W/D) and the lung pathology score were significantly decreased in the XBJ group. The histological results also demonstrated the attenuation effect of XBJ on CLP-induced lung inflammation. The results of the present study indicated that XBJ has a significantly reduced CLP-induced lung permeability by upregulating Tollip expression. The protective effects of XBJ suggest its therapeutic potential in CLP-induced acute lung injury treatment.

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.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Effects of enoxaparin on myeloperoxidase release during hemodialysis

Myeloperoxidase (MPO) is a proteolytic and prooxidant enzyme largely assembled with the vascular wall, and a heparin-binding protein. We studied if low-molecular-weight heparin enoxaparin administered for hemodialysis (HD) anticoagulation causes systemic MPO activation. Plasma MPO levels were measured in patients undergoing maintenance HD with an intravenous bolus of enoxaparin. Patients were retested during HD employing dialyzers with heparin-grafted polyacrylonitrile membrane and no systemic enoxaparin administration. During enoxaparin-anticoagulated HD plasma MPO levels strikingly increased in all patients (8.6-fold at 10 minutes and 3.3-fold at 120 minutes, both P < 0.0001). The increments were directly associated with the enoxaparin dosage and strongly inversely with the predialysis levels of the enzyme. The increase in plasma MPO during systemic heparin-free HD was significantly less pronounced. Enoxaparin administered for HD anticoagulation induces a marked and dose-dependent increase in plasma MPO as a plausibly favorable result of the liberation of the enzyme from the vascular wall.

N-acetyl-heparin attenuates acute lung injury caused by acid aspiration mainly by antagonizing histones in mice

Acute lung injury (ALI) is the leading cause of death in intensive care units. Extracellular histones have recently been recognized to be pivotal inflammatory mediators. Heparin and its derivatives can bind histones through electrostatic interaction. The purpose of this study was to investigate 1) the role of extracellular histones in the pathogenesis of ALI caused by acid aspiration and 2) whether N-acetyl-heparin (NAH) provides more protection than heparin against histones at the high dose. ALI was induced in mice via intratracheal instillation of hydrochloric acid (HCl). Lethality rate, blood gas, myeloperoxidase (MPO) activity, lung edema and pathological changes were used to evaluate the degree of ALI. Heparin/NAH was administered intraperitoneally, twice a day, for 3 days or until death. Acid aspiration caused an obvious increase in extracellular histones. A significant correlation existed between the concentration of HCl aspirated and the circulating histones. Heparin/NAH (10 mg/kg) improved the lethality rate, blood gas, MPO activity, lung edema and pathological score. At a dose of 20 mg/kg, NAH still provided protection, however heparin tended to aggravate the injury due to hemorrhagic complications. The specific interaction between heparin and histones was verified by the binding assay. In summary, high levels of extracellular histones can be pathogenic in ALI caused by acid aspiration. By neutralizing extracellular histones, heparin/NAH can offer similar protection at the moderate doses. At the high dose, NAH provides better protection than heparin.

Ursolic acid attenuates lipopolysaccharide-induced acute lung injury in a mouse model

AIM

To assess whether ursolic acid (UA) can attenuate lipopolysachharide (LPS)-induced acute lung injury and improve the survival time in a mouse model.

MATERIALS & METHODS

The mice were challenged with LPS and survival time was monitored from 0-96 h after LPS treatment. TNF-α, IL-6, IL-1β, HMGB1, nitric oxide (NO) and IL-10 concentration in serum were measured by ELISA. Myeloperoxidase activity, malondialdehyde, lung wet:dry weight ratio and lung permeability in lung tissues were detected. NF-κB, HMGB1 and inducible NO synthase in the lungs were detected by western blot.

RESULTS

UA markedly rescued lethality, improved survival time and lung pathological changes, inhibited TNF-α, IL-6, IL-1β, HMGB1 and NO, and increased IL-10 expression. In addition, UA can also decrease myeloperoxidase, malondialdehyde, lung wet:dry weight ratio and lung permeability. UA attenuated NF-κB, HMGB1 and inducible NO synthase protein expression in the lungs.

CONCLUSION

The results suggest that UA is capable of improving survival time and LPS-induced acute lung injury. UA has a potentially therapeutic role in septic shock.