Gabexate mesilate, a synthetic protease inhibitor, inhibits lipopolysaccharide-induced tumor necrosis factor-alpha production by inhibiting activation of both nuclear factor-kappaB and activator protein-1 in human monocytes

The Role of the Nuclear Factor-Kappa B (NF-κB) Pathway in SARS-CoV-2 Infection

COVID-19 is a global health threat caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is associated with a significant increase in morbidity and mortality. The present review discusses nuclear factor-kappa B (NF-κB) activation and its potential therapeutical role in treating COVID-19. COVID-19 pathogenesis, the major NF-κB pathways, and the involvement of NF-κB in SARS-CoV-2 have been detailed. Specifically, NF-κB activation and its impact on managing COVID-19 has been discussed. As a central player in the immune and inflammatory responses, modulating NF-κB activation could offer a strategic avenue for managing SARS-CoV-2 infection. Understanding the NF-κB pathway's role could aid in developing treatments against SARS-CoV-2. Further investigations into the intricacies of NF-κB activation are required to reveal effective therapeutic strategies for managing and combating the SARS-CoV-2 infection and COVID-19.

Inhibition of Listeria Monocytogenes HtrA Protease with Camostat, Gabexate and Nafamostat Mesylates and the Binding Mode of the Inhibitors

In many bacteria, the High Temperature requirement A (HtrA) protein functions as a chaperone and protease. HtrA is an important factor in stress tolerance and plays a significant role in the virulence of several pathogenic bacteria. Camostat, gabexate and nafamostat mesylates are serine protease inhibitors and have recently shown a great impact in the inhibition studies of SARS-CoV2. In this study, the inhibition of Listeria monocytogenes HtrA (LmHtrA) protease activity was analysed using these three inhibitors. The cleavage assay, using human fibrinogen and casein as substrates, revealed that the three inhibitors effectively inhibit the protease activity of LmHtrA. The agar plate assay and spectrophotometric analysis concluded that the inhibition of nafamostat (IC₅₀ value of 6.6 ± 0.4 µM) is more effective compared to the other two inhibitors. Previous studies revealed that at the active site of the protease, these inhibitors are hydrolysed and one of the hydrolysates is covalently bound to the active site serine. To understand the mode of binding of these inhibitors at the active site of LmHtrA, docking of the inhibitors followed by molecular dynamics simulations were carried out. Analysis of the LmHtrA-inhibitor complex structures revealed that the covalently bound inhibitor is unable to occupy the S1 pocket of the LmHtrA which is in contrast to the previously determined camostat and nafamostat complex structures. This observation provides the first glimpse of the substrate specificity of LmHtrA which is not known. The obtained results also suggest that the development of novel inhibitors of LmHtrA and its homologs with active site architecture similar to LmHtrA can be pursued with suitable modification of these inhibitors. To date, only a very few studies have been carried out on identifying the inhibitors of HtrA proteolytic activity.

The Multifaceted Roles of Mast Cells in Immune Homeostasis, Infections and Cancers

Mast cells (MCs) play important roles in normal immune responses and pathological states. The location of MCs on the boundaries between tissues and the external environment, including gut mucosal surfaces, lungs, skin, and around blood vessels, suggests a multitude of immunological functions. Thus, MCs are pivotal for host defense against different antigens, including allergens and microbial pathogens. MCs can produce and respond to physiological mediators and chemokines to modulate inflammation. As long-lived, tissue-resident cells, MCs indeed mediate acute inflammatory responses such as those evident in allergic reactions. Furthermore, MCs participate in innate and adaptive immune responses to bacteria, viruses, fungi, and parasites. The control of MC activation or stabilization is a powerful tool in regulating tissue homeostasis and pathogen clearance. Moreover, MCs contribute to maintaining the homeostatic equilibrium between host and resident microbiota, and they engage in crosstalk between the resident and recruited hematopoietic cells. In this review, we provide a comprehensive overview of the functions of MCs in health and disease. Further, we discuss how mouse models of MC deficiency have become useful tools for establishing MCs as a potential cellular target for treating inflammatory disorders.

Therapeutic Strategies for Disseminated Intravascular Coagulation Associated with Aortic Aneurysm

Aortic aneurysms are sometimes associated with enhanced-fibrinolytic-type disseminated intravascular coagulation (DIC). In enhanced-fibrinolytic-type DIC, both coagulation and fibrinolysis are markedly activated. Typical cases show decreased platelet counts and fibrinogen levels, increased concentrations of fibrin/fibrinogen degradation products (FDP) and D-dimer, and increased FDP/D-dimer ratios. Thrombin-antithrombin complex or prothrombin fragment 1 + 2, as markers of coagulation activation, and plasmin-α₂ plasmin inhibitor complex, a marker of fibrinolytic activation, are all markedly increased. Prolongation of prothrombin time (PT) is not so obvious, and the activated partial thromboplastin time (APTT) is rather shortened in some cases. As a result, DIC can be neither diagnosed nor excluded based on PT and APTT alone. Many of the factors involved in coagulation and fibrinolysis activation are serine proteases. Treatment of enhanced-fibrinolytic-type DIC requires consideration of how to control the function of these serine proteases. The cornerstone of DIC treatment is treatment of the underlying pathology. However, in some cases surgery is either not possible or exacerbates the DIC associated with aortic aneurysm. In such cases, pharmacotherapy becomes even more important. Unfractionated heparin, other heparins, synthetic protease inhibitors, recombinant thrombomodulin, and direct oral anticoagulants (DOACs) are agents that inhibit serine proteases, and all are effective against DIC. Inhibition of activated coagulation factors by anticoagulants is key to the treatment of DIC. Among them, DOACs can be taken orally and is useful for outpatient treatment. Combination therapy of heparin and nafamostat allows fine-adjustment of anticoagulant and antifibrinolytic effects. While warfarin is an anticoagulant, this agent is ineffective in the treatment of DIC because it inhibits the production of coagulation factors as substrates without inhibiting activated coagulation factors. In addition, monotherapy using tranexamic acid in cases of enhanced-fibrinolytic-type DIC may induce fatal thrombosis. If tranexamic acid is needed for DIC, combination with anticoagulant therapy is of critical importance.

Discovery of TMPRSS2 Inhibitors from Virtual Screening as a Potential Treatment of COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has prompted researchers to pivot their efforts to finding antiviral compounds and vaccines. In this study, we focused on the human host cell transmembrane protease serine 2 (TMPRSS2), which plays an important role in the viral life cycle by cleaving the spike protein to initiate membrane fusion. TMPRSS2 is an attractive target and has received attention for the development of drugs against SARS and Middle East respiratory syndrome. Starting with comparative structural modeling and a binding model analysis, we developed an efficient pharmacophore-based approach and applied a large-scale in silico database screening for small-molecule inhibitors against TMPRSS2. The hits were evaluated in the TMPRSS2 biochemical assay and the SARS-CoV-2 pseudotyped particle entry assay. A number of novel inhibitors were identified, providing starting points for the further development of drug candidates for the treatment of coronavirus disease 2019.

Discovery of TMPRSS2 inhibitors from virtual screening

The SARS-CoV-2 pandemic has prompted researchers to pivot their efforts to finding antiviral compounds and vaccines. In this study, we focused on the human host cell transmembrane protease serine 2 (TMPRSS2), which plays an important role in the viral life cycle by cleaving the spike protein to initiate membrane fusion. TMPRSS2 is an attractive target and has received attention for the development of drugs against SARS and MERS. Starting with comparative structural modeling and binding model analysis, we developed an efficient pharmacophore-based approach and applied a large-scale in silico database screening for small molecule inhibitors against TMPRSS2. The hits were evaluated in the TMPRSS2 biochemical assay and the SARS-CoV-2 pseudotyped particle (PP) entry assay. A number of novel inhibitors were identified, providing starting points for further development of drug candidates for the treatment of COVID-19.

Novel therapeutic compounds for prostate adenocarcinoma treatment: An analysis using bioinformatic approaches and the CMap database

INTRODUCTION

Prostate adenocarcinoma is the most frequently diagnosed malignancy, particularly for people >70 years old. The main challenge in the treatment of advanced neoplasm is bone metastasis and therapeutic resistance for known oncology drugs. Novel treatment methods to prolong the survival time and improve the life quality of these specific patients are required. The present study attempted to screen potential therapeutic compounds for the tumor through bioinformatics approaches, in order to provide conceptual treatment for this malignant disease.

METHODS

Differentially expressed genes were obtained from the Gene Expression Omnibus database and submitted into the Connectivity Map database for the detection of potentially associated compounds. Target genes were extracted from the search results. Functional annotation and pathway enrichment were performed for the confirmation. Survival analysis was used to measure potential therapeutic effects.

RESULTS

It was revealed that 3 compounds (vanoxerine, tolnaftate, and gabexate) may help to prolong the disease-free survival time from tumor metastasis of patients with the tumor. A total of 6 genes [also-keto reductase family 1 member C3 (AKR1C3), collagen type III α 1 chain (COL3A1), lipoprotein lipase (LPL), glucuronidase, β pseudogene 11 (GUSBP11), apolipoprotein E (APOE), and collagen type I α 1 chain (COL1A1)] were identified to be the potential therapeutic targets for the aforementioned compounds.

CONCLUSION

In the present study, it was speculated that 3 compounds may function as the potential therapeutic drugs of bone metastatic prostate adenocarcinoma; however, further studies verifying vitro and in vivo are necessary.

Renin-Angiotensin System and Coronavirus Disease 2019: A Narrative Review

Although clinical manifestations of the 2019 novel coronavirus disease pandemic (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), are mainly respiratory symptoms, patients can also develop severe cardiovascular damage. Therefore, understanding the damage caused by SARS-COV-2 to the cardiovascular system and the underlying mechanisms is fundamental. The cardiovascular damage may be related to the imbalance of the renin-angiotensin-system (RAS) as this virus binds the Angiotensin-Converting-Enzyme 2 (ACE2), expressed on the lung alveolar epithelial cells, to enter into cells. Virus internalization may cause a downregulation of ACE2 on host cell surface that could lead to a local increased level of angiotensin II (AII) and a reduced level of angiotensin 1-7 (A1-7). An imbalance between these angiotensins may be responsible for the lung and heart damage. Pharmacological strategies that interfere with the viral attachment to ACE2 (umifenovir and hydroxychloroquine/chloroquine) or that modulate the RAS (analogous of A1-7 and ACE2, losartan) are in clinical development for COVID-19. The use of RAS inhibitors has also become a matter of public concern as these drugs may increase the mRNA expression and levels of ACE2 and impact the virulence and transmission of SARS-COV-2. Data on the effect of RAS inhibitors on ACE2 mRNA expression are scarce. Scientific societies expressed their opinion on continuing the therapy with RAS inhibitors in patients with COVID-19 and underlying cardiovascular diseases. In conclusion, RAS may play a role in SARS-COV-2-induced cardiac and pulmonary damage. Further studies are needed to better understand the role of RAS in COVID-19 and to guide decision on the use of RAS inhibitors.

Repurposing drugs against the main protease of SARS-CoV-2: mechanism-based insights supported by available laboratory and clinical data

The ongoing global pandemic of COVID-19 has brought life to almost a standstill with the implementation of lockdowns and social distancing as some of the preventive measures in the absence of any approved specific therapeutic interventions. To combat this crisis, research communities worldwide are falling back on the existing repertoire of approved/investigational drugs to probe into their anti-coronavirus properties. In this report, we describe our unique efforts in identifying potential drugs that could be repurposed against the main protease of SARS-CoV-2 (SARS-CoV-2 M^pro). To achieve this goal, we have primarily exploited the principles of 'neighbourhood behaviour' in the protein 3D (workflow-I) and chemical 2D structural space (workflow-II) coupled with docking simulations and insights into the possible modes of action of the selected candidates from the available literature. This integrative approach culminated in prioritizing 29 potential repurpose-able agents (20 approved drugs and 9 investigational molecules) against SARS-CoV-2 M^pro. Apart from the approved/investigational anti-viral drugs, other notable hits include anti-bacterial, anti-inflammatory, anti-cancer and anti-coagulant drugs. Our analysis suggests that some of these drugs have the potential to simultaneously modulate the functions of viral proteins and the host response system. Interestingly, many of these identified candidates (12 molecules from workflow-I and several molecules, belonging to the chemical classes of alkaloids, tetracyclines, peptidomimetics, from workflow-II) are suggested to possess anti-viral properties, which is supported by laboratory and clinical data. Furthermore, this work opens a new avenue of research to probe into the molecular mechanism of action of many drugs, which are known to demonstrate anti-viral activity but are so far not known to target viral proteases.

Small Molecule NF-κB Pathway Inhibitors in Clinic

Nuclear factor kappa B (NF-κB) signaling is implicated in all major human chronic diseases, with its role in transcription of hundreds of gene well established in the literature. This has propelled research into targeting the NF-κB pathways for modulating expression of those genes and the diseases mediated by them. In-spite of the critical, but often promiscuous role played by this pathway and the inhibition causing adverse drug reaction, currently many biologics, macromolecules, and small molecules that modulate this pathway are in the market or in clinical trials. Furthermore, many marketed drugs that were later found to also have NF-κB targeting activity were repurposed for new therapeutic interventions. Despite the rising importance of biologics in drug discovery, small molecules got around 76% of US-FDA (Food and Drug Administration-US) approval in the last decade. This encouraged us to review information regarding clinically relevant small molecule inhibitors of the NF-κB pathway from cell surface receptor stimulation to nuclear signaling. We have also highlighted the underexplored targets in this pathway that have potential to succeed in clinic.

Immune response in COVID-19: addressing a pharmacological challenge by targeting pathways triggered by SARS-CoV-2

To date, no vaccines or effective drugs have been approved to prevent or treat COVID-19 and the current standard care relies on supportive treatments. Therefore, based on the fast and global spread of the virus, urgent investigations are warranted in order to develop preventive and therapeutic drugs. In this regard, treatments addressing the immunopathology of SARS-CoV-2 infection have become a major focus. Notably, while a rapid and well-coordinated immune response represents the first line of defense against viral infection, excessive inflammatory innate response and impaired adaptive host immune defense may lead to tissue damage both at the site of virus entry and at systemic level. Several studies highlight relevant changes occurring both in innate and adaptive immune system in COVID-19 patients. In particular, the massive cytokine and chemokine release, the so-called "cytokine storm", clearly reflects a widespread uncontrolled dysregulation of the host immune defense. Although the prospective of counteracting cytokine storm is compelling, a major limitation relies on the limited understanding of the immune signaling pathways triggered by SARS-CoV-2 infection. The identification of signaling pathways altered during viral infections may help to unravel the most relevant molecular cascades implicated in biological processes mediating viral infections and to unveil key molecular players that may be targeted. Thus, given the key role of the immune system in COVID-19, a deeper understanding of the mechanism behind the immune dysregulation might give us clues for the clinical management of the severe cases and for preventing the transition from mild to severe stages.

Treatments for COVID-19: emerging drugs against the coronavirus

The Coronavirus disease 19 (COVID-19) outbreak has been recognized as a global threat to public health. It is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and no effective therapies currently exist against this novel viral agent. Along with extensive public health measures, an unprecedented global effort in identifying effective drugs for the treatment is being implemented. Potential drug targets are emerging as the result of a fast-evolving understanding of SARS-CoV-2 virology, host response to the infection, and clinical course of the disease. This brief review focuses on the latest and most promising pharmacological treatments against COVID-19 currently under investigation and discuss their potential use based on either documented efficacy in similar viral infections, or their activity against inflammatory syndromes. Ongoing clinical trials are also emphasized.

Developing Small Molecule Therapeutics for the Initial and Adjunctive Treatment of Snakebite

The World Health Organization (WHO) recently added snakebite envenoming to the priority list of Neglected Tropical Diseases (NTD). It is thought that ~75% of mortality following snakebite occurs outside the hospital setting, making the temporal gap between a bite and antivenom administration a major therapeutic challenge. Small molecule therapeutics (SMTs) have been proposed as potential prereferral treatments for snakebite to help address this gap. Herein, we discuss the characteristics, potential uses, and development of SMTs as potential treatments for snakebite envenomation. We focus on SMTs that are secretory phospholipase A2 (sPLA2) inhibitors with brief exploration of other potential drug targets on venom molecules.

Nucleic-acid based gene therapy approaches for sepsis

Despite advances in overall medical care, sepsis and its sequelae continue to be an embarrassing clinical entity with an unacceptably high mortality rate. The central reason for high morbidity and high mortality of sepsis and its sequelae is the lack of an effective treatment. Previous clinical trials have largely failed to identify an effective therapeutic target to improve clinical outcomes in sepsis. Thus, the key goal favoring the outcome of septic patients is to devise innovative and evolutionary therapeutic strategies. Gene therapy can be considered as one of the most promising novel therapeutic approaches for nasty disorders. Since a number of transcription factors, such as nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), play a pivotal role in the pathophysiology of sepsis that can be characterized by the induction of multiple genes and their products, sepsis may be regarded as a gene-related disorder and gene therapy may be considered a promising novel therapeutic approach for treatment of sepsis. In this review article, we provide an up-to-date summary of the gene-targeting approaches, which have been developed in animal models of sepsis. Our review sheds light on the molecular basis of sepsis pathology for the development of novel gene therapy approaches and leads to the conclusion that future research efforts may fully take into account gene therapy for the treatment of sepsis.

Lack of Enteral Nutrition Delays Nuclear Factor Kappa B Activation in Peritoneal Exudative Cells in a Murine Glycogen-Induced Peritonitis Model

BACKGROUND

Early enteral nutrition is associated with a lower incidence of intraabdominal abscess in severely injured patients than parenteral nutrition (PN). We explored the underlying mechanisms by examining the influence of nutrition route on nuclear factor kappaB (NFkappaB) activation in peritoneal exudative cells (PECs) and peritoneal cytokine levels.

METHODS

Thirty male Institute Cancer Research mice were randomized to chow (n = 10), IV PN (n = 10), or intragastric (IG) PN (n = 10) and fed for 5 days. PECs were harvested at 2 or 4 hours after intraperitoneal injection of 2 mL of 1% glycogen. Intranuclear NFkappaB activity in PECs was examined by laser scanning cytometry. Cytokine (tumor necrosis factor-alpha [TNF-alpha], macrophage inflammatory protein-2 [MIP-2], interleukin-10 [IL-10]) levels in peritoneal lavaged fluid were determined by enzyme-linked immunosorbent assay.

RESULTS

Intranuclear NFkappaB at 2 hours was significantly higher in the chow and IG-PN groups than in the IV-PN group. TNF-alpha and IL-10 levels of the chow group were significantly higher than those of IV-PN mice at 2 hours, whereas those of IG-PN mice were midway between those of the chow and IV-PN groups. MIP-2 was significantly higher in the chow group than in the IG-PN and IV-PN mice at 2 hours. TNF-alpha levels correlated positively with intranuclear NFkappaB activity in PECs.

CONCLUSIONS

Enteral nutrition may improve peritoneal defense by preserving early NFkappaB activation in PECs and cytokine responses.

Effects of gabexate mesilate on coagulopathy and organ dysfunction in rats with endotoxemia: a potential use of thrombelastography in endotoxin-induced sepsis

Sepsis and its associated multiple organ failure are related to high mortality in critical patients. Several studies have reported that gabexate mesilate, a synthetic inhibitor of trypsin-like serine protease, protects tissues/organs against injury in the models of endotoxemia. The aim of this study was to examine whether gabexate mesilate could attenuate coagulopathy and organ dysfunction in lipopolysaccharide (LPS)-induced sepsis model by using thrombelastography (TEG). LPS (7.5  mg/kg/h, intravenouly for 4  h) was administered to male adult Wistar rats. Some of the LPS rats received a continuous infusion of gabexate mesilate (10  mg/kg/h, intravenously for 8.5  h) for 30  min before the LPS administration. Variable parameters of hemodynamics, biochemistry, hemostasis and inflammatory response were measured for 6  h after the LPS infusion. TEG variables (R-time, K-time, α-angle, and maximal amplitude) were also measured. The pretreatment of LPS rats with gabexate mesilate significantly attenuated the lung, liver and kidney dysfunction, consumptive coagulopathy, the increases in serum tumor necrosis factor-α, interleukin-6, plasma thrombin-antithrombin complex and plasminogen activator inhibitor-1, and neutrophils infiltration score in lung, liver and kidney, compared with the LPS alone group. In addition, TEG parameters correlated with tissue and liver injury in the late phase of endotoxemia. In particular, a strong negative correlation between maximal amplitude at 4  h and Ln (lactate dehydrogenase) at 6  h after LPS infusion was noted (r = -0.752, P < 0.001, R = 0.566). These results indicate that beneficial effects of anticoagulants (e.g. gabexate mesilate) in endotoxemia could be monitored by TEG per se.

Changes in extra- and intracellular pH in hepatocytes exposed to gabexate mesilate

Gabexate mesilate (GM) is a synthetic inhibitor of plasmatic and pancreatic serine proteases licensed for the treatment of pancreatitis. Here we show that in suspensions of isolated hepatocytes, profound changes in extracellular, cytoplasmic, and vesicular pH occur after addition of GM. Isolated hepatocytes obtained by collagenase perfusion of rat liver were pre-incubated with 1, 2, and 4 mM GM. Extracellular pH (pH in the incubation medium) was measured by a conventional pH electrode, cytosolic and vesicular pH were measured by fluorescence changes of 2',7'-biscarboxyethyl-5,6-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and fluorescein dextran, respectively. Incubation of hepatocytes with GM resulted in a dose-dependent decrease of extracellular pH. Cytosolic pH decreased rapidly and markedly in a dose-dependent manner during the first minutes and gradually returned towards baseline. Simultaneously, GM induced a rapid alkalinization of acidic vesicles. The presence of bis-(p-nitrophelyl) phosphate (BNPP), an esterase inhibitor, reduced the extent of extracellular acidification. Incubation of hepatocytes in the presence of dimethylamiloride, an Na+/H+ exchanger inhibitor, or in a sodium-free medium, did not modify the rate and extent of extracellular acidification. GM, a commercially available pharmacological agent, could be useful to manipulate extra- and intracellular pH.

Regulating surgical oncotaxis to improve the outcomes in cancer patients

Excessive surgical stress and postoperative complications cause a storm of perioperative cytokine release, which has been shown to enhance tumor metastasis in experimental models. We have named this phenomenon "surgical oncotaxis". The mechanisms that underpin this process are thought to be excessive corticosteroid secretion, coagulopathy in the peripheral vasculature, immune suppression and excessive production of reactive oxygen species. Nuclear factor-kappa B (NFkB) activation plays a key role in these mechanisms. Minimally invasive surgical techniques should be used, and postoperative complications should be avoided whenever possible to lessen the impact of surgical oncotaxis. Furthermore, there may be a role for a small preoperative dose of corticosteroid or the use of free radical scavengers in the perioperative period. Recently, there has been a great deal of interest in omega-3 fatty acid, because it regulates NFkB activation. The use of multimodal treatments that regulate surgical oncotaxis may be as important as chemotherapy for determining the outcome of patients with cancer undergoing surgery.

Coagulation challenges after severe injury with hemorrhagic shock

During the past 50 years, there have been huge changes in the approach to coagulopathic bleeding following the treatment of traumatic hemorrhagic shock (HS). Treatment during the 1960s consisted primarily of physiologic saline (balanced electrolyte solution [BES]) and whole blood supported with sodium bicarbonate for acidosis. Subsequent coagulopathy was assumed to be caused by lack of the labile factors (FV and FVIII) which were then replaced by fresh whole blood. The decade of 1970s saw the implementation of component therapy by the American Blood Banking Association so that HS was treated with BES and packed red blood cells (RBC). A new paradigm had to be learned to determine when and how much fresh frozen plasma (FFP) was needed to restore all coagulation factors. By the end of 1970s, most trauma centers were supplementing BES and RBC with FFP in patients with severe injuries requiring massive transfusion of more than one circulating blood volume. By the 1980s, the use of FFP skyrocketed, creating a crisis for the American Blood Banking Association. This led to a National Institute of Health Consensus Development Conference which concluded that FFP should be given to only those patients who had a documented coagulopathy as evidenced by a prolongation of the prothrombin time and the partial thromboplastin time. Restriction of FFP replacement to patients with proven coagulopathy after treatment for HS led to postoperative bleeding which was sometimes fatal. During the 1990s, uncontrolled clinical studies and rigorously controlled animal studies showed that FFP should be administered before the onset of proven coagulopathy with prolongation of the prothrombin time and partial thromboplastin time. Later during the 1990s, recombinant-activated factor VII (FVIIa) was purported to provide quicker hemostasis in patients treated with HS. The efficacy of FVIIa supplementation is still being assessed. During the 2010s, the military surgeons promoted the use of a hemostatic regimen which consists of platelets, RBC, and FFP in a 1:1:1 ratio. This recommendation is still being assessed with different authors reporting benefits and detriments. Throughout these years, an unusual entity of disseminated intravascular coagulation (DIC) was known to complicate the resuscitation of seriously injured patients with HS. This syndrome was typically seen after treatment of HS and was associated with abnormal bleeding plus respiratory failure and renal failure thought to be caused by a combination of micro- and macrothromboses. The early studies suggested that the best therapy for breaking this viscous cycle of bleeding and intravascular coagulation was by infusing fresh whole blood. The theoretical benefits of administering heparin to prevent the thrombosis and epsilon-aminocaproic acid to enhance lysis have not proven beneficial. DIC is also seen in association with toxic exposures, including snake bites. Epsilon-aminocaproic acid may be beneficial in that setting. Many of the intricate understandings of DIC remain elusive and are still being studied.

Effects of a synthetic protease inhibitor (gabexate mesilate) and a neutrophil elastase inhibitor (sivelestat sodium) on acid-induced lung injury in rats

The present study was designed to examine the combined effects of a synthetic protease inhibitor, gabexate mesilate, with a specific neutrophil elastase inhibitor, sivelestat sodium, on acid-induced lung injury. Adult male Sprague-Dawley rats weighing 300-350 g were anaesthetised intraperitoneally with pentobarbitone sodium and the right jugular vein was cannulated. Following tracheostomy, rats were ventilated mechanically and underwent intratracheal instillation of hydrochloric acid (HCl, 0.1N 1.5 ml/kg) or normal saline. Gabexate mesilate (10mg/kg, i.p.) and/or sivelestat sodium (10mg/kg/h, i.v.) were administered 30 min before HCl instillation. Bronchoalveolar lavage fluid samples were obtained 5h after HCl instillation. In bronchoalveolar lavage fluid, the HCl-induced increases in total nucleated cell counts, neutrophil counts, optical density at 412 nm as an index of pulmonary haemorrhage, concentrations of albumin and cytokine-induced neutrophil chemoattractant (CINC) were significantly attenuated by either gabexate mesilate or sivelestat sodium treatment. Gabexate mesilate or sivelestat sodium treatment also significantly attenuated the wet to dry weight ratio induced by HCl. However, combined treatment with both gabexate mesilate and sivelestat sodium did not show additive effects on HCl-induced lung injury, compared with single treatments. These findings suggested that gabexate mesilate and sivelestat sodium each exhibited protective effects on acid-induced lung injury, but that synergistic effects of both agents are limited in this acid-induced lung injury model.

Arginine-enriched total parenteral nutrition improves survival in peritonitis by normalizing NFkappaB activation in peritoneal resident and exudative leukocytes

BACKGROUND

Enteral nutrition maintains peritoneal defense more effectively than parenteral nutrition, at least partly by preserving NFkappaB activation in peritoneal cells. We hypothesized that arginine (ARG)-enriched parenteral nutrition would normalize NFkappaB activation in peritoneal leukocytes, thereby improving the survival of peritonitis models.

METHODS

A total of 105 ICR mice were randomized to chow (n=33), IV feeding of a standard (STD) total parenteral nutrition (STD-TPN) solution (ARG 0.3%) (n=35), or 1% ARG-TPN solution (n=37), and fed accordingly for 5 days.Experiment 1: Thirty mice were used for intranuclear NFkappaB measurement in peritoneal resident cells (PRCs). After incubation with lipopolysaccharide (LPS: 0, 1, 10 microg/mL) for 30 minutes, intranuclear NFkappaB activity was examined by laser scanning cytometry.Experiment 2: Fifty-one mice were injected with 2 mL of 1% glycogen intraperitoneally. Peritoneal exudative cells (PECs) were obtained at 2 or 4 hours after glycogen administration for NFkappaB measurement. Cytokine (TNFalpha, IL-10) levels in peritoneal lavage fluid were also determined by ELISA.Experiment 3: After 5 days of feeding, 24 mice underwent cecal ligation and puncture. Survival was observed up to 5 days.

RESULTS

Experiment 1: Intranuclear NFkappaB levels in the ARG-TPN and chow groups increased dose-dependently after LPS stimulation, while the level in the STD-TPN group was unchanged.Experiment 2: Intranuclear NFkappaB level was significantly higher at 2 hours in the chow than in the STD-TPN group, whereas in the ARG-TPN mice the level was midway between those of the chow and STD-TPN groups. TNFalpha and IL-10 levels of the chow group were significantly higher than those of STD-TPN mice at 2 hours. TNFalpha was significantly higher in the ARG-TPN group than in the STD-TPN group, but the IL-10 level showed no recovery.Experiment 3: Survival times were significantly reduced in the STD-TPN as compared with the chow group, though ARG-TPN improved survival.

CONCLUSION

ARG-enriched TPN is a surrogate for enteral feeding which maintains peritoneal defense by preserving NFkappaB activation in peritoneal resident and exudative leukocytes.

Metformin, an antidiabetic agent, suppresses the production of tumor necrosis factor and tissue factor by inhibiting early growth response factor-1 expression in human monocytes in vitro

Metformin, an antidiabetic agent, has been shown to reduce atherothrombotic disease in diabetic patients independent of antihyperglycemic effect. Recent studies have demonstrated that metformin attenuates the proinflammatory responses in human vascular wall cells and macrophages. However, the detailed molecular mechanisms underlying these therapeutic effects remain unclear. In the present study, we investigated the effects of metformin on tumor necrosis factor (TNF) production and tissue factor (TF) expression in isolated human monocytes stimulated with lipopolysaccharide (LPS) or oxidized low-density lipoprotein (oxLDL). Metformin significantly inhibited both TNF production and TF expression in isolated human monocytes stimulated with LPS or oxLDL. Metformin also significantly inhibited TNF and TF mRNA in human monocytes stimulated with LPS. Although metformin did not inhibit the activation of either nuclear factor-kappaB or activator protein-1, it inhibited the expression of early growth response factor-1 (Egr-1) and phosphorylation of extracellular signal-regulated protein kinase (ERK) 1/2 in monocytes stimulated with LPS or oxLDL. These results suggest that metformin may attenuate the inflammatory responses, at least in part, by suppressing the production of both TNF and TF through the inhibition of the ERK1/2-Egr-1 pathway in human monocytes.

ONO 3403, a synthetic serine protease inhibitor, inhibits lipopolysaccharide-induced tumor necrosis factor-{alpha} and nitric oxide production and protects mice from lethal endotoxic shock

ONO 3403, a new synthetic serine protease inhibitor, is a derivative of camostat mesilate and has a higher protease-inhibitory activity. The effect of ONO 3403 on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α and nitric oxide (NO) production in RAW 264.7 macrophage-like cells was examined. ONO 3403 significantly inhibited LPS-induced TNF-α production at a lower concentration than camostat mesilate. It also inhibited LPS-induced NO production. Their inhibition was responsible for the reduced mRNA expression of TNF-α and inducible NO synthase. In LPS-stimulated cells, ONO 3403 prevented the augmentation of MyD88 expression and inhibited the phosphorylation of IκB-α, stress-activated protein kinase (SAPK) and IRF-3, and the production of interferon-β. ONO 3403 abolished the elevation of the extracellular serine protease activity in response to LPS. Further, it reduced the circulating TNF-α level, hepatic injury and mortality in mice receiving an injection of D-galactosamine and LPS. ONO 3403 was suggested to inhibit LPS-induced inflammatory responses via inactivation of MyD88-dependent and independent pathways.

Gabexate mesilate inhibits the expression of HMGB1 in lipopolysaccharide-induced acute lung injury

High mobility group box 1 (HMGB1) is an important late mediator of acute lung injury. Gabexate mesilate (GM) is a synthetic protease inhibitor with some anti-inflammatory action. We aimed to evaluate the effect of GM on HMGB1 in lipopolysaccharide (LPS)-induced lung injury in rats. Prior to the injection of LPS to induce lung injury, rats were administered saline or GM. Injury to the lung and expression of HMGB1, plasminogen activator inhibitor-1 (PAI-1), and protease-activated receptor-2 (PAR-2) were examined. In an accompanying in vitro study, we performed LPS stimulation under GM administration in a mouse macrophage cell line and measured the quantity of HMGB1 and cytokines in the supernatant, and cell signal in the cells. Histologic examination revealed that interstitial edema, leukocytic infiltration, and HMGB1 protein expression were markedly reduced in the GM+LPS group compared wih the LPS group. Furthermore, LPS-induced increases in PAI-1 and PAR-2 activity and in plasma HMGB1 concentrations were lower in the rats given both GM and LPS than in the rats given LPS alone. Release of HMGB1 and cytokines from the cell after the administration of LPS were decreased by GM. Phosphorylation of IκB was inhibited by GM. GM may have inhibited PAI-1 and PAR-2, thereby indirectly inhibiting HMGB1 and reducing tissue damage in the lung. This indicates that GM can inhibit lung injury induced by LPS in rats. GM is a candidate for use in novel strategies to prevent or minimize lung injury in sepsis.

Antithrombin inhibits lipopolysaccharide-induced tumor necrosis factor-alpha production by monocytes in vitro through inhibition of Egr-1 expression

BACKGROUND

Antithrombin (AT) improves the outcome of septic patients with intravascular coagulation. However, the mechanisms underlying the therapeutic benefits of AT are not fully understood. Tumor necrosis factor-alpha (TNF-alpha) plays a critical role in the development of organ failure and intravascular coagulation in sepsis.

AIM

This study aimed to elucidate a molecular mechanism by which AT inhibits TNF-alpha production.

METHODS

Human peripheral monocyte was stimulated by lipopolysaccharide (LPS) and TNF-alpha concentration in media was measured. Levels of phosphorylation of extracellular signal-regulated protein kinases (ERK) 1/2 and early growth response factor-1 (Egr-1) were estimated by western blotting or by electrophoretic mobility shift assay.

RESULTS

Antithrombin (3 U mL(-1)) inhibited TNF-alpha production by monocytes stimulated with LPS. Conversely, chemically modified AT that lacks affinity for heparin did not. AT inhibited the phosphorylation of ERK 1/2 and decreased the expression of Egr-1 in LPS-stimulated monocytes. However, it did not affect the activation of either nuclear factor-kappaB or activator protein-1. Pretreatment with KT5720, a protein kinase A inhibitor, reversed the inhibitory effect of AT on the LPS-induced phosphorylation of ERK1/2. Although 2 U mL(-1) AT slightly inhibited TNF-alpha production by LPS-stimulated monocytes, it significantly inhibited TNF-alpha production in the presence of a low concentration of beraprost, a stable derivative of prostacyclin.

CONCLUSIONS

These observations suggest that AT might inhibit LPS-induced production of TNF-alpha by inhibiting the increase in Egr-1 expression in monocytes via interaction with heparin-like substances expressed on the cell surface.

Nafamostat mesilate inhibits high-mobility group box 1 by lipopolysaccharide stimulation in murine macrophage RAW 264.7

In recent investigations, high-mobility group box 1 (HMGB1) has been recognized to be an important factor in the development of sepsis. On the other hand, a serine protease inhibitor, nafamostat mesilate (NM) inhibits the enzyme activities of various protease and coagulation factors. We examined whether NM could inhibit HMGB1 in a rat sepsis model and thus could potentially be useful for treating sepsis. We administered NM to rats before administering lipopolysaccharide and thereafter measured the HMGB1 levels of the serum and lung tissue. We used a mouse macrophage cell line and we performed lipopolysaccharide stimulation under NM administration and thereafter measured the quantity of HMGB1 and cytokines in the supernatant, and cell signal in the cells. We were thereby able to reduce the degree of injury to pulmonary tissue by administering NM. The HMGB1 levels of the serum and lung tissue were thus found to be inhibited. This action was confirmed at the cell level, and the release of HMGB1 and cytokines from the cell decreased. Regarding the cell signal in each cell, we observed the inhibition of the phosphorylation of IkappaB. We thus concluded that it is possible to prevent the occurrence of pulmonary disorders in an endotoxic shock model by administering NM, however, this also inhibits the cell signal in a cell, mainly by the phosphorylation of IkappaB, thereby inhibiting the HMGB1 levels. Our findings thus suggest that the administration of NM may therefore potentially improve the condition of patients who have septic shock.

Systemic inflammatory response syndrome (SIRS): molecular pathophysiology and gene therapy

In recent years, extensive basic science research has led to a clear understanding of the molecular mechanisms contributing to the pathophysiology of sepsis. Sepsis is now defined as a systemic inflammatory response syndrome (SIRS) in which there is an identifiable focus of infection. SIRS can be also precipitated by non-infective events such as trauma, pancreatitis, and surgery. As a consequence of an overactive SIRS response, the function of various organ systems may be compromised, resulting in multiple organ dysfunction syndrome (MODS) and death. Production and activation of multiple proinflammatory genes are likely to play a key role in the pathogenesis of MODS development. This review article focuses on the molecular mechanisms and components involved in the pathogenesis of severe sepsis. This includes cellular targets of sepsis-inducing bacterial products and their signaling pathways with a major emphasis on transcription factors and new therapeutic approaches to severe sepsis.

Route and type of nutrition influence nuclear factor kappaB activation in peritoneal resident cells

Morbidity of intra-abdominal abscess is increased when severely injured patients are fed parenterally. Lack of enteral nutrition appears to impair peritoneal cavity host defense. Because the transcription factor nuclear factor kappaB (NFkappaB) regulates various genes involved in inflammatory responses and its activation is important for host defense, we hypothesized that enteral nutrition would preserve appropriate NFkappaB activation in peritoneal resident cells (PRCs), the first defense line against peritoneal contamination. Mice (n = 105) were randomized to chow (n = 38), intravenous (IV)-total parenteral nutrition (TPN) (n = 34), or intragastric (IG)-TPN (n = 33) for 5 days' feeding. In experiment 1, PRCs were harvested for measurement of intranuclear NFkappaB activity with or without in vitro lipopolysaccharide (LPS) stimulation using laser scanning cytometry and enzyme-linked immunoabsorbant assay. PRC numbers tended to be higher in enterally fed mice than in IV-TPN mice. The main PRC subpopulation was macrophages in all groups. NFkappaB activation was increased in response to LPS in chow mice, whereas there was no increase in the IV-TPN group. IG-TPN mice demonstrated moderate NFkappaB activation. In experiment 2, mice underwent cecal ligation and puncture (CLP). Survival was observed up to 5 days. In another set of mice, tumor necrosis factor (TNF) alpha levels of peritoneal lavaged fluid were measured 4 h after CLP. Survival times after CLP improved in the chow and IG-TPN groups compared with the IV-TPN group. TNFalpha levels were significantly higher in the chow than in the IV-TPN group. In conclusion, parenteral nutrition decreases PRC number and blunts NFkappaB activation in PRCs. These changes may impair host defense in the peritoneal cavity.

Activation of the adenosine A3 receptor in RAW 264.7 cells inhibits lipopolysaccharide-stimulated tumor necrosis factor-alpha release by reducing calcium-dependent activation of nuclear factor-kappaB and extracellular signal-regulated kinase 1/2

Bacterial lipopolysaccharide (LPS) activates the immune system and promotes inflammation via Toll-like receptor (TLR) 4, which regulates the synthesis and release of tumor necrosis factor (TNF)-alpha and other inflammatory cytokines. Previous studies have shown that the nucleoside adenosine suppresses LPS-stimulated TNF-alpha release in human UB939 macrophages by activating an adenosine A(3) receptor (A(3)AR) subtype on these cells. In this study, we examined the mechanism(s) underlying A(3)AR-dependent inhibition of TNF-alpha release in a mouse (RAW 264.7) cell line. Treatment of RAW 264.7 cells with LPS (3 mug/ml) increased TNF-alpha release, which was reduced in a dose-dependent manner by adenosine analogs N(6)-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (IB-MECA) and R-phenylisopropyladenosine and reversed by selective A(3)AR blockade. The increase in TNF-alpha release was preceded by an increase in intracellular Ca(2+) levels. Inhibition of intracellular Ca(2+) release by IB-MECA, a selective agonist of the A(3)AR, or with BAPTA-AM, an intracellular Ca(2+) chelator, reduced LPS-stimulated TNF-alpha release. Activation of the A(3)AR or inhibition of intracellular Ca(2+) release also reduced LPS-stimulated nuclear factor-kappaB (NF-kappaB) activation and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Similar inhibition by A(3)AR was observed for LPS-stimulated inducible nitric-oxide synthase. These data support the contention that inhibition of LPS-stimulated release of inflammatory molecules, such as TNF-alpha and NO via the A(3)AR, involves suppression of intracellular Ca(2+)signaling, leading to suppression of NF-kappaB and ERK1/2 pathways.

Chronic treatment with agents that stabilize cytosolic IkappaB-alpha enhances survival and improves resting membrane potential in MDX muscle fibers subjected to chronic passive stretch

The potential pathogenic role of increased NFkappaB signaling in passively stretched dystrophic skeletal muscle was examined by treating adult mdx mice with an agent that stabilized cytosolic IkappaB-alpha (pyrollidine dithiocarbamate, PDTC)and examining the effects of this treatment on the chronically stretched mdx triangularis sterni (TS) muscle. Daily PDTC treatment significantly increased the number of surviving striated TS fibers regardless of age. TS fibers from untreated mdx mice had significantly lower resting potentials (RPs) than nondystrophic mice. Treatment with GdCl3 to block resting Ca2+ influx had no effect on RP in either nondystrophic or mdx preparations. Daily treatment with PDTC significantly improved the RP regardless of age. These results are consistent with the hypothesis that passive stretch activates an NFkappaB-mediated pathogenic mechanism in dystrophic muscle and suggest that agents which stabilize cytosolic IkappaB-alpha levels may be useful for treating Duchenne and related muscular dystrophies.

Effect of glutamate on inflammatory responses of intestine and brain after focal cerebral ischemia

AIM: To study the modulation of glutamate on post-ischemic intestinal and cerebral inflammatory responses in a ischemic and excitotoxic rat model.

METHODS: Adult male rats were subjected to bilateral carotid artery occlusion for 15 min and injection of monosodium glutamate intraperitoneally, to decapitate them at selected time points. Tumor necrosis factor alpha (TNF-α) level and nuclear factor kappa B (NF-κB) activity were determined by enzyme-linked immunosorbant assay (ELISA) and electrophoretic mobility shift assay (EMSA), respectively. Hemodynamic parameters were monitored continuously during the whole process of cerebral ischemia and reperfusion.

RESULTS: Monosodium glutamate (MSG) treated rats displayed statistically significant high levels of TNF-α in cerebral and intestinal tissues within the first 6 h of ischemia. The rats with cerebral ischemia showed a minor decrease of TNF-α production in cerebral and intestinal tissues. The rats with cerebral ischemia and treated with MSG displayed statistically significant low levels of TNF-α in cerebral and intestinal tissues. These results correlated significantly with NF-κB production calculated at the same intervals. During experiment, the mean blood pressure and heart rates in all groups were stable.

CONCLUSION: Glutamate is involved in the mechanism of intestinal and cerebral inflammation responses. The effects of glutamate on cerebral and intestinal inflammatory responses after ischemia are up-regulated at the transcriptional level, through the NF-κB signal transduction pathway.

Camostat mesilate attenuates pancreatic fibrosis via inhibition of monocytes and pancreatic stellate cells activity

Camostat mesilate (CM), an oral protease inhibitor, has been used clinically for the treatment of chronic pancreatitis in Japan. However, the mechanism by which it operates has not been fully understood. Our aim was to evaluate the therapeutic efficacy of CM in the experimental pancreatic fibrosis model induced by dibutyltin dichloride (DBTC), and we also determined the effect of CM on isolated monocytes and panceatic stellate cells (PSCs). In vivo, chronic pancreatitis was induced in male Lewis rats by single administration of 7 mg/kg DBTC and a special diet containing 1 mg/g CM was fed to the DBTC+CM-treated group from day 7, while the DBTC-treated group rats were fed a standard diet. At days 0, 7, 14 and 28, the severity of pancreatitis and fibrosis was examined histologically and enzymologically in both groups. In vitro, monocytes were isolated from the spleen of a Lewis rat, and activated with lipopolysaccharide stimulation. Thereafter, the effect of CM on monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-alpha) production from monocytes was examined. Subsequently, cultured rat PSCs were exposed to CM and tested to see whether their proliferation, MCP-1 production and procollagen alpha1 messenger RNA expression was influenced by CM. In vivo, the oral administration of CM inhibited inflammation, cytokines expression and fibrosis in the pancreas. The in vitro study revealed that CM inhibited both MCP-1 and TNF-alpha production from monocytes, and proliferation and MCP-1 production from PSCs. However, procollagen alpha1 expression in PSCs was not influenced by CM. These results suggest that CM attenuated DBTC-induced rat pancreatic fibrosis via inhibition of monocytes and PSCs activity.

Urinary trypsin inhibitor reduces LPS-induced hypotension by suppressing tumor necrosis factor-alpha production through inhibition of Egr-1 expression

Although urinary trypsin inhibitor (UTI) has been shown to inhibit tumor necrosis factor (TNF)-alpha- production, the detailed mechanism(s) remains unclear. This study was undertaken to elucidate the molecular mechanism(s) underlying this inhibitory effect in monocytes in vitro and in rats given lipopolysaccharide (LPS). TNF-alpha production by monocytes stimulated with LPS (100 ng/ml) was inhibited by UTI at concentrations higher than 100 U/ml. Expression of early growth response factor-1 (Egr-1) and phosphorylation of extracellular signal-regulated protein kinases 1/2 in monocytes stimulated with LPS were inhibited by UTI. UTI (50,000 U/kg i.v.) inhibited LPS (5 mg/kg i.v.)-induced increases in lung tissue levels of Egr-1, TNF-alpha mRNA, and TNF-alpha in rats. UTI inhibited LPS-induced hypotension by inhibiting pulmonary induction of inducible nitric oxide synthase (iNOS). We previously demonstrated that anti-TNF-alpha antibody and aminoguanidine, a selective inhibitor of iNOS, reduced LPS-induced hypotension in this animal model. Furthermore, we also reported that reduction of LPS-induced coagulation abnormalities in rats did not affect inflammatory responses and hypotension in this animal model. Taken together, these observations strongly suggested that UTI inhibited LPS-induced production of TNF-alpha by inhibiting activation of the extracellular signal-regulated protein kinases 1/2-Egr-1 pathway in monocytes, which might at least partly contribute to reduction of hypotension through inhibition of iNOS induction in rats given LPS.

Heme oxygenase-1 in cholecystokinin-octapeptipe attenuated injury of pulmonary artery smooth muscle cells induced by lipopolysaccharide and its signal transduction mechanism

AIM: To study the effect of cholecystokinin-octapeptide (CCK-8) on lipopolysaccharide (LPS) -induced pulmonary artery smooth muscle cell (PASMCs) injury and the role of heme oxygenase-1 (HO-1), and to explore the regulation mechanism of c-Jun N-terminal kinase (JNK) and activator protein-1 (AP-1) signal transduction pathway in inducing HO-1 expression further.

METHODS: Cultured PASMCs were randomly divided into 4 or 6 groups: normal culture group, LPS (10 mg/L), CCK-8 (10^-6 mol/L) plus LPS (10 mg/L) group, CCK-8 (10^-6 mol/L) group, zinc protoporphyrin 9 (ZnPPIX) (10^{- 6} mol/L) plus LPS (10 mg/L) group, CCK-8 (10^-6 mol/L) plus ZnPPIX and LPS (10 mg/L) group. Seven hours after LPS administration, ulterstructrual changes and content of malondialdehyde (MDA) of PASMCs in each group were investigated by electron microscopy and biochemical assay respectively. HO-1 mRNA and protein of PASMCs in the former4 groups were examined by reverse transcriptase polymerase chain reaction (RT-PCR) and immunocytochemistry staining. Changes of c-fos expression and activation of JNK of PASMCs in the former 4 groups were detected with immunocytochemistry staining and Western blot 30 min after LPS administration.

RESULTS: The injuries of PASMCs and the increases of MDA content induced by LPS were alleviated and significantly reduced by CCK-8 (P < 0.05). The specific HO-1 inhibitor-ZnPPIX could worsen LPS-induced injuries and weaken the protective effect of CCK-8. The expressions of c-fos, p-JNK protein and HO-1 mRNA and protein were all slightly increased in LPS group, and significantly enhanced by CCK-8 further (P < 0.05).

CONCLUSION: HO-1 may be a key factor in CCK-8 attenuated injuries of PASMCs induced by LPS, and HO-1 expression may be related to the activation of JNK and activator protein (AP-1).