The lung in sepsis: guilty or innocent?

MicroRNA-1258 suppresses oxidative stress and inflammation in septic acute lung injury through the Pknox1-regulated TGF-β1/SMAD3 cascade

AIM

The study was to clarify the mechanism of miR-1258 targeting Prep1 (pKnox1) to control Transforming Growth Factor β1 (TGF-β1)/SMAD3 pathway in septic Acute Lung Injury (ALI)-induced oxidative stress and inflammation.

METHODS

BEAS-2B cells and C57BL/6 mice were used to make in vitro and in vivo septic ALI models, respectively. miR-1258 expression was checked by RT-qPCR. After transfection in the in vitro experimental model, inflammation, oxidative stress, viability, and apoptosis were observed through ELISA, MTT, and flow cytometry.

RESULTS

In the in vivo model after miR-1258 overexpression treatment, inflammation, oxidative stress, and lung injury were further investigated. The targeting relationship between miR-1258 and Pknox1 was tested. Low miR-1258 was expressed in septic ALI patients, LPS-treated BEAS-2B cells, and mice. Upregulated miR-1258 prevented inflammation, oxidative stress, and apoptosis but enhanced the viability of LPS-treated BEAS-2B cells. The impact of upregulated miR-1258 on LPS-treated BEAS-2B cells was mitigated by inhibiting Pknox1 expression. MiR-1258 overexpression had the alleviating effects on inflammation, oxidative stress, and lung injury of LPS-injured mice through suppressing Pknox1 expression and TGF-β1/SMAD3 cascade activation.

CONCLUSIONS

The study concludes that miR-1258 suppresses oxidative stress and inflammation in septic ALI through the Pknox1-regulated TGF-β1/SMAD3 cascade.

Platelet P2Y12 signalling pathway in the dysregulated immune response during sepsis

Sepsis is a complicated pathological condition in response to severe infection. It is characterized by a strong systemic inflammatory response, where multiple components of the immune system are involved. Currently, there is no treatment for sepsis. Blood platelets are known for their role in haemostasis, but they also participate in inflammation through cell-cell interaction and the secretion of inflammatory mediators. Interestingly, an increase in platelet activation, secretion, and aggregation with other immune cells (such as monocytes, T-lymphocytes and neutrophils) has been detected in septic patients. Therefore, antiplatelet therapy in terms of P2Y12 antagonists has been evaluated as a possible treatment for sepis. It was found that blocking P2Y12 receptors decreased platelet marker expression and limited attachment to immune cells in some studies, but not in others. This review addresses the role of platelets in sepsis and discusses whether antagonizing P2Y12 signalling pathways can alter the disease outcome. Challenges in studying P2Y12 antagonists in sepsis also are discussed. LINKED ARTICLES: This article is part of a themed issue on Platelet purinergic receptor and non-thrombotic disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.4/issuetoc.

Central glucagon-like peptide 1 receptor activation inhibits Toll-like receptor agonist-induced inflammation

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) exert anti-inflammatory effects relevant to the chronic complications of type 2 diabetes. Although GLP-1RAs attenuate T cell-mediated gut and systemic inflammation directly through the gut intraepithelial lymphocyte GLP-1R, how GLP-1RAs inhibit systemic inflammation in the absence of widespread immune expression of the GLP-1R remains uncertain. Here, we show that GLP-1R activation attenuates the induction of plasma tumor necrosis factor alpha (TNF-α) by multiple Toll-like receptor agonists. These actions are not mediated by hematopoietic or endothelial GLP-1Rs but require central neuronal GLP-1Rs. In a cecal slurry model of polymicrobial sepsis, GLP-1RAs similarly require neuronal GLP-1Rs to attenuate detrimental responses associated with sepsis, including sickness, hypothermia, systemic inflammation, and lung injury. Mechanistically, GLP-1R activation leads to reduced TNF-α via α1-adrenergic, δ-opioid, and κ-opioid receptor signaling. These data extend emerging concepts of brain-immune networks and posit a new gut-brain GLP-1R axis for suppression of peripheral inflammation.

Gut microbial metabolite hyodeoxycholic acid targets the TLR4/MD2 complex to attenuate inflammation and protect against sepsis

Sepsis, a critical condition resulting from the systemic inflammatory response to a severe microbial infection, represents a global public health challenge. However, effective treatment or intervention to prevent and combat sepsis is still lacking. Here, we report that hyodeoxycholic acid (HDCA) has excellent anti-inflammatory properties in sepsis. We discovered that the plasma concentration of HDCA was remarkably lower in patients with sepsis and negatively correlated with the severity of the disease. Similar changes in HDCA levels in plasma and cecal content samples were observed in a mouse model of sepsis, and these changes were associated with a reduced abundance of HDCA-producing strains. Interestingly, HDCA administration significantly decreased systemic inflammatory responses, prevented organ injury, and prolonged the survival of septic mice. We demonstrated that HDCA suppressed excessive activation of inflammatory macrophages by competitively blocking lipopolysaccharide binding to the Toll-like receptor 4 (TLR4) and myeloid differentiation factor 2 receptor complex, a unique mechanism that characterizes HDCA as an endogenous inhibitor of inflammatory signaling. Additionally, we verified these findings in TLR4 knockout mice. Our study highlights the potential value of HDCA as a therapeutic molecule for sepsis.

LUNG PROTECTIVE POTENTIAL EFFECT OF ZILEUTON DURING ENDOTOXAEMIA MODEL IN MALE MICE

OBJECTIVE

The aim: This study was undertaken to investigatethe possible lung protective potential effect of zileuton during polymicrobial sepsis, through modulation of inflammatory and oxidative stress pathway.

PATIENTS AND METHODS

Materials and methods: 24 adult male Swiss-albino mice aged 8-12 weeks, with a weight of 25-35g, were randomized into 4 equal groups n=6, sham (laparotomy without CLP), CLP (laparotomy with CLP), vehicle (equivalent volume of DMSO 1 hour prior to CLP), and Zileuton (5 mg/kg 1 hour prior to CLP) group. After 24 hrs. of sepsis, the lung tissue harvested and used to assess IL-6, IL-1B, IL-17, LTB-4,12(S) HETE and F2-isoprostane as well as histological examination.

RESULTS

Results: Lung tissue inflammatory mediators IL-6, IL-1B, IL-17, LTB, 12 (S) HETE) and oxidative stress were carried out via ELISA. Lung tissue levels of IL-6, IL-1B, IL-17, LTB4, 12(S) HETE and oxidative stress (F2 isoprostan)level were significantly higher in sepsis group (p<0.05) as compared with sham group, while zileuton combination showed significant (p<0.05) lower level in these inflammatory mediators and oxidative stress as comparedto sepsis group. Histologically, All mice in sepsis group showed a significant (p<0.05) lung tissue injury, while in zileuton pretreated group showed significantly (p<0.05) reduced lung tissue injury.

CONCLUSION

Conclusions: The results of the present study revealed that zileuton has the ability to attenuate lung dysfunction during CLP induced polymicrobial sepsis in male mice through their modulating effects on LTB4,12(S) HETE and oxidative stress downstream signaling pathways and subsequently decreased lungtissue levelsof proinflammatory cytokines (IL-1β, and IL-6,IL-17).

The anti-inflammatory and antioxidant effects of Montelukast on lung sepsis in adult mice

One of the most complex clinical challenges facing medical practice is sepsis-induced lung dysfunction resulting from polymicrobial sepsis. Although many therapeutic approaches have been used in such clinical challenges, there is still further need for a new effective therapeutic approach. The objective of this study was to investigate if Montelukast could protect the lungs during polymicrobial sepsis by regulating inflammatory markers and the oxidative stress pathways. Twenty-four mature male Swiss-albino mice aged 8-12 weeks, with a weight of 20-30 g, were randomized into 4 equal groups (n=6), sham (laparotomy without cecal ligation and puncture (CLP)), CLP (laparotomy with CLP), vehicle 1 (equivalent volume of DMSO 1 hour prior to CLP), Montelukast (10 mg/kg IP 1 hour prior to CLP). Lung tissue pro-inflammatory mediators IL-6, IL-1β, IL-17, LTB-4 12(S) HETE, and oxidative stress were assessed using ELISA. The levels of F2 isoprostane were considerably greater in the sepsis group (p<0.05) as compared to the sham group, while Montelukast was significantly lower (p<0.05) in these inflammatory mediators and oxidative stress as compared to the sepsis group. Histologically, the lung tissue damage was significant (p<0.05) in all mice in the sepsis group, while Montelukast significantly reduced lung tissue injury (p<0.05). The current findings indicated that Montelukast could attenuate lung dysfunction during CLP-induced polymicrobial sepsis in male mice through their modulating effects on pro-inflammatory and oxidative stress downstream signalling pathways and subsequently decrease lung tissue cytokine concentrations (IL-1β, IL-6, IL-17, LTB-4, and 12(S)HETE).

LncRNA H19 acts as miR-301a-3p sponge to alleviate lung injury in mice with sepsis by regulating Adcy1

BACKGROUND

The abnormal expression of long non-coding RNA (lncRNA) is closely related to disease progression. However, the role and mechanism of lncRNA H19 (lncH19) in sepsis-induced lung injury remain to be elucidated.

METHODS

Cercal ligation and puncture (CLP) mice models and lipopolysaccharide (LPS)-induced cell injury model were used to construct sepsis-induced lung injury in vivo and in vitro. The expression of lncH19, microRNA (miR)-301a-3p and adenylate cyclase 1 (Adcy1) mRNA was assessed using quantitative real-time PCR. The concentrations of inflammatory factors were determined by ELISA assay. Cell proliferation and apoptosis were determined using cell counting kit 8 assay, EdU staining and flow cytometry. The protein expression of apoptosis markers and Adcy1 was examined by western blot analysis. Oxidative stress was assessed by detecting the contents of oxidative stress markers. The interaction between miR-301a-3p and lncH19 or Adcy1 was confirmed using RNA pull-down assay, dual-luciferase reporter assay and RIP assay.

RESULTS

LncH19 was lowly expressed in CLP mice models and LPS-induced cell injury models. Overexpressed lncH19 could alleviate CLP-induced lung injury in mice, as well as LPS-induced cell apoptosis, inflammation and oxidative stress. MiR-301a-3p could be sponged by lncH19, and its overexpression could reverse the inhibition of lncH19 on LPS-induced cell injury. Adcy1 was a target of miR-301a-3p, and its expression was upregulated by lncH19. Silencing of Adcy1 could abolish the suppressive effect of miR-301a-3p inhibitor on LPS-induced cell injury.

CONCLUSION

LncH19 might inhibit sepsis-induced lung injury through acting as a sponge of miR-301a-3p to upregulate Adcy1.Highlights:LncH19 overexpression relieves CLP-induced lung injury and LPS-induced cell injury.LncH19 directly sponges miR-301a-3p.MiR-301a-3p targets Adcy1.

Activated Platelets Autocrine 5-Hydroxytryptophan Aggravates Sepsis-Induced Acute Lung Injury by Promoting Neutrophils Extracellular Traps Formation

Excessive neutrophil extracellular trap (NET) formation is an important contributor to sepsis-induced acute lung injury (ALI). Recent reports indicate that platelets can induce neutrophil extracellular trap formation. However, the specific mechanism remains unclear. Tph1 gene, which encodes the rate-limiting enzyme for peripheral 5-hydroxytryptophan (5-HT) synthesis, was knocked out in mice to simulate peripheral 5-HT deficiency. Cecal ligation and puncture (CLP) surgery was performed to induce sepsis. We found that peripheral 5-HT deficiency reduced NET formation in lung tissues, alleviated sepsis-induced lung inflammatory injury, and reduced the mortality rate of CLP mice. In addition, peripheral 5-HT deficiency was shown to reduce the accumulation of platelets and NETs in the lung of septic mice. We found that platelets from wild-type (WT), but not Tph1 knockout (Tph1^−/−), mice promote lipopolysaccharide (LPS)-induced NET formation. Exogenous 5-HT intervention increased LPS-induced NET formation when Tph1^−/− platelets were co-cultured with WT neutrophils. Therefore, our study uncovers a mechanism by which peripheral 5-HT aggravated sepsis-induced ALI by promoting NET formation in the lung of septic mice.

Oxytocin and Related Peptide Hormones: Candidate Anti-Inflammatory Therapy in Early Stages of Sepsis

Sepsis is a potentially life-threatening systemic inflammatory syndrome characterized by dysregulated host immunological responses to infection. Uncontrolled immune cell activation and exponential elevation in circulating cytokines can lead to sepsis, septic shock, multiple organ dysfunction syndrome, and death. Sepsis is associated with high re-hospitalization and recovery may be incomplete, with long term sequelae including post-sepsis syndrome. Consequently, sepsis continues to be a leading cause of morbidity and mortality across the world. In our recent review of human chorionic gonadotropin (hCG), we noted that its major properties including promotion of fertility, parturition, and lactation were described over a century ago. By contrast, the anti-inflammatory properties of this hormone have been recognized only more recently. Vasopressin, a hormone best known for its anti-diuretic effect, also has anti-inflammatory actions. Surprisingly, vasopressin's close cousin, oxytocin, has broader and more potent anti-inflammatory effects than vasopressin and a larger number of pre-clinical studies supporting its potential role in limiting sepsis-associated organ damage. This review explores possible links between oxytocin and related octapeptide hormones and sepsis-related modulation of pro-inflammatory and anti-inflammatory activities.

Adipose-derived mesenchymal stem cells attenuate acute lung injury and improve the gut microbiota in septic rats

Background

We hypothesized that adipose-derived mesenchymal stem cells (ADMSCs) may ameliorate sepsis-induced acute lung injury (ALI) and change microorganism populations in the gut microbiota, such as that of Firmicutes and Bacteroidetes.

Methods

A total of 60 male adult Sprague-Dawley (SD) rats were separated into three groups: the sham control (SC) group, the sepsis induced by cecal ligation and puncture (CLP) group, and the ADMSC treatment (CLP-ADMSCs) group, in which rats underwent the CLP procedure and then received 1 × 10⁶ ADMSCs. Rats were sacrificed 24 h after the SC or CLP procedures. To study the role of ADMSCs during ALI caused by sepsis and examine the impact of ADMSCs on the gut microbiome composition, rat lungs were histologically evaluated using hematoxylin and eosin (H&E) staining, serum levels of pro-inflammatory factors were detected using enzyme-linked immunosorbent assay (ELISA), and fecal samples were collected and analyzed using 16S rDNA sequencing.

Results

The serum levels of inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-6, were significantly increased in rats after the CLP procedure, but were significantly decreased in rats treated with ADMSCs. Histological evaluation of the rat lungs yielded results consistent with the changes in IL-6 levels among all groups. Treatment with ADMSCs significantly increased the diversity of the gut microbiota in rats with sepsis. The principal coordinates analysis (PCoA) results showed that there was a significant difference between the gut microbiota of the CLP-ADMSCs group and that of the CLP group. In rats with sepsis, the proportion of Escherichia–Shigella (P = 0.01) related to lipopolysaccharide production increased, and the proportion of Akkermansia (P = 0.02) related to the regulation of intestinal mucosal thickness and the maintenance of intestinal barrier function decreased. These changes in the gut microbiota break the energy balance, aggravate inflammatory reactions, reduce intestinal barrier functions, and promote the translocation of intestinal bacteria. Intervention with ADMSCs increased the proportion of beneficial bacteria, reduced the proportion of harmful bacteria, and normalized the gut microbiota.

Conclusions

Therapeutically administered ADMSCs ameliorate CLP-induced ALI and improves gut microbiota, which provides a potential therapeutic mechanism for ADMSCs in the treatment of sepsis.

Role of Nrf2 and Its Activators in Respiratory Diseases

Transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a major regulator of antioxidant response element- (ARE-) driven cytoprotective protein expression. The activation of Nrf2 signaling plays an essential role in preventing cells and tissues from injury induced by oxidative stress. Under the unstressed conditions, natural inhibitor of Nrf2, Kelch-like ECH-associated protein 1 (Keap1), traps Nrf2 in the cytoplasm and promotes the degradation of Nrf2 by the 26S proteasome. Nevertheless, stresses including highly oxidative microenvironments, impair the ability of Keap1 to target Nrf2 for ubiquitination and degradation, and induce newly synthesized Nrf2 to translocate to the nucleus to bind with ARE. Due to constant exposure to external environments, including diverse pollutants and other oxidants, the redox balance maintained by Nrf2 is fairly important to the airways. To date, researchers have discovered that Nrf2 deletion results in high susceptibility and severity of insults in various models of respiratory diseases, including bronchopulmonary dysplasia (BPD), respiratory infections, acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), asthma, idiopathic pulmonary fibrosis (IPF), and lung cancer. Conversely, Nrf2 activation confers protective effects on these lung disorders. In the present review, we summarize Nrf2 involvement in the pathogenesis of the above respiratory diseases that have been identified by experimental models and human studies and describe the protective effects of Nrf2 inducers on these diseases.

Increased Systemic Cytokine/Chemokine Expression in Asthmatic and Non-asthmatic Patients with Bacterial, Viral or Mixed Lung Infection

This study was aimed to determine the profiles of serum cytokines (IL-1β, TNF-α, IL-4, IL-5) and chemokines (MCP-1: monocyte chemoattract protein-1 and RANTES: regulated on activation normal T cell expressed and secreted) in individuals with an asthmatic versus a non-asthmatic background with bacterial, viral or mixed acute respiratory infection. Asthmatic (n = 14) and non-asthmatic (n = 29) patients with acute viral, bacterial or mixed (bacterial and viruses) respiratory infection were studied. Patients were also analysed as individuals with pneumonia or bronchitis. Healthy individuals with similar age and sex (n = 10) were used as controls. Cytokine/chemokine content in serum was determined by ELISA. Increased cytokine/chemokine concentration in asthmatic and non-asthmatic patients was observed. However, higher concentrations of chemokines (MCP-1 and RANTES) in asthmatic patients infected by viruses, bacteria or bacteria and viruses (mixed) than in non-asthmatic patients were observed. In general, viral and mixed infections were better cytokine/chemokine inducers than bacterial infection. Cytokine/chemokine expression was similarly increased in both asthmatic and non-asthmatic patients with pneumonia or bronchitis, except that RANTES remained at normal levels in bronchitis. Circulating cytokine profiles induced by acute viral, bacterial or mixed lung infection were not related to asthmatic background, except for chemokines that were increased in asthmatic status.

NFAT5 participates in seawater inhalation‑induced acute lung injury via modulation of NF-κB activity

Nuclear factor of activated T cells 5 (NFAT5) is a transcription factor that can be activated by extracellular tonicity. It has been reported that NFAT5 may increase the transcription of certain osmoprotective genes in the renal system, and the aim of the current study was to explore the role of NFAT5 in seawater inhalation-induced acute lung injury. Though establishing the model of seawater inhalation-induced acute lung injury, it was demonstrated that seawater inhalation enhanced the transcription and protein expression of NFAT5 (evaluated by reverse transcription-polymerase chain reaction, immunohistochemistry stain and western blotting) and activation of nuclear factor (NF)-κB (evaluated by western blotting and mRNA expression levels of three NF-κB-dependent genes) both in lung tissue and rat alveolar macrophage cells (NR8383 cells). When expression of NFAT5 was reduced in NR8383 cells using an siRNA targeted to NFAT5, the phosphorylation of NF-κB and transcription of NF-κB-dependent genes were significantly reduced. In addition, the elevated content of certain inflammatory cytokines [tumor necrosis factor α, interleukin (IL)-1 and IL-8] were markedly reduced. In conclusion, NFAT5 serves an important pathophysiological role in seawater inhalation-induced acute lung injury by modulating NF-κB activity, and these data suggest that NFAT5 may be a promising therapeutic target.

[Impairment of oxygenation of patients in surgical intensive care : Early symptom of severe sepsis]

BACKGROUND

Sepsis and septic shock are major contributors to morbidity and mortality in intensive care patients. Early identification and adequate therapy are of utmost importance to reduce the still high mortality in patients with severe sepsis. Many of the pathophysiologic changes are nonspecific. Thus, a combination of symptoms and laboratory results are necessary to confirm the diagnosis. Impairment of the Horovitz index is identified as being a primal prognostic criterion for early diagnosis in serious progression of sepsis, after exclusion of a few differential diagnoses. Based on this fact, the prevalence of this symptom compared to other sepsis parameters is of specific interest.

METHOD

In a retrospective study 33 cases of serious sepsis were analysed during the patient's course of intensive care treatment focusing on oxygenation. The deterioration of oxygenation, meaning a drop in the Horovitz index below 200 mm Hg (25.7 kPa) or a decrease in paO₂ by 67.5 mm Hg (9 kPa) in spontaneously breathing patients with sepsis was the mean inclusion criteria. We compared the sequence of occurrence of known sepsis markers (e. g. PCT, WBC, CRP) with the deterioration in oxygenation to answer the question whether impairment of oxygenation could be an early symptom of severe sepsis. The Mann Whitney U‑test and a discriminant analysis were performed to verify differences of the variables investigated between surviving and deceased patients. Furthermore a regression analysis was performed to confirm the results of the discriminant analysis.

RESULTS

The mean drop in the Horovitz index was 90 ± 24 mm Hg (12 ± 3.2 kPa) within 4.5 h respectively. This was highly significant (p < 0.001). In all patients impairment of oxygenation indicated an individual onset and further progression of a serious sepsis. In more than ¾ of all cases this symptom occurred in an earlier stage than other organ dysfunctions. In 79 % of cases, patients showed an impairment of oxygenation before PCT increased on values of >2 ng/ml. In 76 % of cases impairment of oxygenation occurred earlier than all other investigated parameters. Significant differences were found between surviving and deceased patients regarding to their age as well as the timeframe from the beginning of impaired oxygenation to the onset of the effect of the administered antibiotics. These two parameters (age, time to sufficient antibiotic therapy) were confirmed by regression analysis and showing similar effect coefficients, age 1.09 and time to sufficient antibiotic therapy 1.04 respectively.

CONCLUSION

An urgent worsening of pulmonary function in patients in intensive care requires immediate differential diagnostics due to substantial therapeutic consequences. Our results confirm that impairment of pulmonary oxygenation is the first prognostic symptom of severe onset of sepsis. Consequently, we recommend that this parameter be considered in diagnostic staging. After exclusion of a few differential diagnoses impairment of oxygenation can be the very first symptom of severe sepsis. The patient's age and time to sufficient antibiotic therapy are two very important prognostic factors with respect to mortality. Early and sufficient antibiotic therapy, and in a few cases surgical intervention are of utmost importance.

Salvia miltiorrhiza: Traditional medicinal uses, chemistry, and pharmacology

Salvia miltiorrhiza Bunge (SM) is a very popular medicinal plant that has been extensively applied for many years to treat various diseases, especially coronary heart diseases and cerebrovascular diseases, either alone or in combination with other Chinese plant-based medicines. Although a large number of studies on SM have been performed, they are scattered across a variety of publications. The present review is an up-to-date summary of the published scientific information about the traditional uses, chemical constituents, pharmacological effects, side effects, and drug interactions with SM, in order to lay the foundation for further investigations and better utilization of SM. SM contains diverse chemical components including diterpenoid quinones, hydrophilic phenolic acids, and essential oils. Many pharmacological studies have been done on SM during the last 30 years, focusing on the cardiovascular and cerebrovascular effects, and the antioxidative, neuroprotective, antifibrotic, anti-inflammatory, and antineoplastic activities. The research results strongly support the notion that SM has beneficial therapeutic properties and has a potential of being an effective adaptogenic remedy.

Dexamethasone Suppressed LPS-Induced Matrix Metalloproteinase and Its Effect on Endothelial Glycocalyx Shedding

The aim of this study is to determine the mechanism of sepsis-induced vascular hyperpermeability and the beneficial effect of glucocorticoid in protecting vascular endothelium. Male Sprague-Dawley rats were given either a bolus intraperitoneal injection of a nonlethal dose of LPS (Escherichia coli 055:B5, 10 mg/kg, Sigma) or vehicle (pyrogen-free water). Animals of treatment groups were also given either dexamethasone (4 mg/kg, 30 min prior to LPS injection) or the matrix metalloproteinases (MMPs) inhibitor doxycycline (4 mg/kg, 30 min after LPS injection). Both activities and protein levels of MMP-2 (p < 0.001) and MMP-9 (p < 0.001) were significantly upregulated in aortic homogenates from LPS-treated rats, associated with decreased ZO-1 (p < 0.001) and syndecan-1 (p = 0.011) protein contents. Both dexamethasone and doxycycline could significantly inhibit MMPs activity and reserve the expressions of ZO-1 and syndecan-1. The inhibition of MMPs by dexamethasone was significantly lower than that by doxycycline, while the rescue of syndecan-1 expression from LPS-induced endotoxemic rat thoracic aorta was significantly higher in the dexamethasone-treated compared to the doxycycline-treated (p = 0.03). In conclusion, activation of MMPs plays important role in regulating ZO-1 and syndecan-1 protein levels in LPS mediated endothelial perturbation. Both dexamethasone and doxycycline inhibit activation of MMPs that may contribute to the rescue of ZO-1 and syndecan-1 expression.

Changes in intestinal microflora in rats with acute respiratory distress syndrome

AIM

To implement high-throughput 16S rDNA sequencing to study microbial diversity in the fecal matter of rats with acute lung injury/acute respiratory distress syndrome (ALI/ARDS).

METHODS

Intratracheal instillation of lipopolysaccharide was used to induce ALI, and the pathological changes in the lungs and intestines were observed. D-lactate levels and diamine oxidase (DAO) activities were determined by enzymatic spectrophotometry. The fragments encompassing V4 16S rDNA hypervariable regions were PCR amplified from fecal samples, and the PCR products of V4 were sequenced by Illumina MiSeq.

RESULTS

Increased D-lactate levels and DAO activities were observed in the model group (P < 0.01). Sequencing results revealed the presence of 3780 and 4142 species in the control and model groups, respectively. The percentage of shared species was 18.8419%. Compared with the control group, the model group had a higher diversity index and a lower number of species of Fusobacteria (at the phylum level), Helicobacter and Roseburia (at the genus level) (P < 0.01). Differences in species diversity, structure, distribution and composition were found between the control group and early ARDS group.

CONCLUSION

The detection of specific bacteria allows early detection and diagnosis of ALI/ARDS.

Increased cytokine/chemokines in serum from asthmatic and non-asthmatic patients with viral respiratory infection

BACKGROUND

Respiratory viral infections can induce different cytokine/chemokine profiles in lung tissues and have a significant influence on patients with asthma. There is little information about the systemic cytokine status in viral respiratory-infected asthmatic patients compared with non-asthmatic patients.

OBJECTIVES

The aim of this study was to determine changes in circulating cytokines (IL-1β, TNF-α, IL-4, IL-5) and chemokines (MCP1: monocyte chemoattractant protein-1 and RANTES: regulated on activation normal T cell expressed and secreted) in patients with an asthmatic versus a non-asthmatic background with respiratory syncytial virus, parainfluenza virus or adenovirus respiratory infection. In addition, human monocyte cultures were incubated with respiratory viruses to determine the cytokine/chemokine profiles.

PATIENTS/METHODS

Patients with asthmatic (n = 34) and non-asthmatic (n = 18) history and respiratory infections with respiratory syncytial virus, parainfluenza, and adenovirus were studied. Healthy individuals with similar age and sex (n = 10) were used as controls. Cytokine/chemokine content in blood and culture supernatants was determined by ELISA. Monocytes were isolated by Hystopaque gradient and cocultured with each of the above-mentioned viruses.

RESULTS

Similar increased cytokine concentrations were observed in asthmatic and non-asthmatic patients. However, higher concentrations of chemokines were observed in asthmatic patients. Virus-infected monocyte cultures showed similar cytokine/chemokine profiles to those observed in the patients.

CONCLUSIONS

Circulating cytokine profiles induced by acute viral lung infection were not related to asthmatic status, except for chemokines that were already increased in the asthmatic status. Monocytes could play an important role in the increased circulating concentration of cytokines found during respiratory viral infections.

Activin, neutrophils, and inflammation: just coincidence?

During the 26 years that have elapsed since its discovery, activin-A, a member of the transforming growth factor β super-family originally discovered from its capacity to stimulate follicle-stimulating hormone production by cultured pituitary gonadotropes, has been established as a key regulator of various fundamental biological processes, such as development, homeostasis, inflammation, and tissue remodeling. Deregulated expression of activin-A has been observed in several human diseases characterized by an immuno-inflammatory and/or tissue remodeling component in their pathophysiology. Various cell types have been recognized as sources of activin-A, and plentiful, occasionally contradicting, functions have been described mainly by in vitro studies. Not surprisingly, both harmful and protective roles have been postulated for activin-A in the context of several disorders. Recent findings have further expanded the functional repertoire of this molecule demonstrating that its ectopic overexpression in mouse airways can cause pathology that simulates faithfully human acute respiratory distress syndrome, a disorder characterized by strong involvement of neutrophils. This finding when considered together with the recent discovery that neutrophils constitute an important source of activin-A in vivo and earlier observations of upregulated activin-A expression in diseases characterized by strong activation of neutrophils may collectively imply a more intimate link between activin-A expression and neutrophil reactivity. In this review, we provide an outline of the functional repertoire of activin-A and suggest that this growth factor functions as a guardian of homeostasis, a modulator of immunity and an orchestrator of tissue repair activities. In this context, a relationship between activin-A and neutrophils may be anything but coincidental.

Berberine reduces leukocyte adhesion to LPS-stimulated endothelial cells and VCAM-1 expression both in vivo and in vitro

Leukocyte adhesion to endothelium plays a critical initiating role in inflammation. Berberine, an anti-inflammatory natural compound, is known to attenuate lipopolysaccharide (LPS)-induced lung injury and improve survival of endotoxemic animals with mechanism not fully clarified. This study investigated the effects of berberine on the LPS-induced leukocyte-endothelial cell adhesion both in vivo and in vitro. We first established an animal model to observe the in vivo LPS-induced adhesion of leukocytes to the endothelium of venules in the lung tissue dose-dependently. Pretreatment of LPS-stimulated rats with berberine for 1 h reduced the leukocyte-endothelium adhesion and vascular cell adhesion molecule-1 (VCAM-1) expression in lung. Pretreatment of LPS-stimulated vascular endothelial cells with berberine also dose-dependently decreased the number of adhered THP-1 cells and VCAM-1 expression at both RNA and protein levels. Berberine was further confirmed to inhibit the nuclear translocation and DNA binding activity of LPS-activated nuclear factor-kappa B (NF-kappa B). These data demonstrated an additional molecular mechanism for the profound anti-inflammatory effect of berberine.

The effect of post-treatment N-acetylcysteine in LPS-induced acute lung injury of rats

Background

Oxidation plays an important role in acute lung injury. This study was conducted in order to elucidate the effect of repetitive post-treatment of N-acetylcysteine (NAC) in lipopolysaccaride (LPS)-induced acute lung injury (ALI) of rats.

Methods

Six-week-old male Sprague-Dawley rats were divided into 4 groups. LPS (Escherichia coli 5 mg/kg) was administered intravenously via the tail vein. NAC (20 mg/kg) was injected intraperitoneally 3, 6, and 12 hours after LPS injection. Broncho-alveolar lavage fluid (BALF) and lung tissues were obtained to evaluate the ALI at 24 hours after LPS injection. The concentration of tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) were measured in BALF. Nuclear factor κB (NF-κB), lipid peroxidation (LPO), and myeloperoxidase (MPO) were measured using lung tissues. Micro-computed tomography (micro-CT) images were examined in each group at 72 hours apart from the main experiments in order to observe the delayed effects of NAC.

Results

TNF-α and IL-1β concentration in BALF were not different between LPS and NAC treatment groups. The concentration of LPO in NAC treatment group was significantly lower than that of LPS group (5.5±2.8 nmol/mL vs. 16.5±1.6 nmol/mL) (p=0.001). The activity of MPO in NAC treatment group was significantly lower than that of LPS group (6.4±1.8 unit/g vs. 11.2±6.3 unit/g, tissue) (p<0.048). The concentration of NF-κB in NAC treatment group was significantly lower than that of LPS group (0.3±0.1 ng/µL vs. 0.4±0.2 ng/µL) (p=0.0001). Micro-CT showed less extent of lung injury in NAC treatment than LPS group.

Conclusion

After induction of ALI with lipopolysaccharide, the therapeutic administration of NAC partially attenuated the extent of ALI through the inhibition of NF-κB activation.

In vivo and in vitro inhibitory effects of a traditional Chinese formulation on LPS-stimulated leukocyte-endothelial cell adhesion and VCAM-1 gene expression

AIM OF THE STUDY

A traditional Chinese formulation Huang-Lian-Jie-Du-Tang (HLJDT) exerts anti-inflammatory effects. The present study aimed to investigate the effect of HLJDT on the LPS-stimulated leukocyte-endothelial cell adhesion and VCAM-1 gene expression both in vivo and in vitro.

MATERIALS AND METHODS

HLJDT was extracted from rhizoma coptidis, radix scutellariae, cortex phellodendri and fructus gardeniae in a weight rario of 1:1:1:1. In vivo leukocyte-endothelial cell adhesion was observed in rat lung after LPS stimulation (5mg/kg, i.p.) with or without HLJDT (350 or 700mg/kg, i.g.) pretreatment. The protein expression of vascular cell adhesion molecule 1 (VCAM-1) was analyzed by immunohistochemical method. In vitro leukocyte-endothelial cell adhesion was performed by examining the adhesion of THP-1cells to LPS-stimulated human vascular endothelial cells with or without HLJDT pretreatment. The VCAM-1 expression at the RNA and protein levels was investigated by RT-PCR and western blot analysis, respectively. The activation of NF-κB was examined by the nuclear translocation of NF-κB by immunocytochemical method.

RESULTS

In vivo, HLJDT dose-dependently reduced the number of leukocytes adhered to endothelium and VCAM-1 protein expression in lung venules of LPS-challenged rats. In vitro, HLJDT dose-dependently decreased the number of THP-1cells adhered to LPS-stimulated endothelial cells and the expression of VCAM-1 both at the RNA and protein levels. The LPS-induced nuclear translocation of NF-kappa B in endothelial cells was also dose-dependently inhibited by HLJDT.

CONCLUSIONS

The present study demonstrated an additional mechanism underlying the anti-inflmmatory effect of HLJDT by inhibiting the leukocyte-endothelial cell adhesion and VCAM-1 gene expression. The inhibition of NF-kappa B activation by HLJDT might suggest a profound anti-inflammatory consequences.

Improvement of sepsis by hepatocyte growth factor, an anti-inflammatory regulator: emerging insights and therapeutic potential

Sepsis-induced multiple organ failure (MOF) is the most frequent lethal disease in intensive care units. Thus, it is important to elucidate the self-defensive mechanisms of sepsis-induced MOF. Hepatocyte growth factor (HGF) is now recognized as an organotrophic factor, which is essential for organogenesis during embryonic growth and regeneration in adulthood. HGF production is enhanced in response to infectious challenges, but the increase in endogenous HGF levels is transient and insufficient, with a time lag between tissue injuries and HGF upregulation, during progression of septic MOF. Thus, administration of active-formed HGF might be a new candidate for therapeutic development of MOF. HGF has an ability to target endotoxin-challenged macrophages and inhibits the upregulation of inflammatory cytokines through nuclear factor-κB-inactivated mechanisms. HGF also targets the endothelium and epithelium of various organs to suppress local inflammation, coagulation, and apoptotic death. This paper summarizes the novel mechanisms of HGF for attenuating sepsis-related pathological conditions with a focus on sepsis-induced MOF.

Time-dependent expression of endothelin-1 in lungs and the effects of TNF-α blocking peptide on acute lung injury in an endotoxemic rat model

Endothelin (ET)-1 is a potent vasoconstrictor that has been implicated in the pathogenesis of a number of diseases, and some studies suggest that circulating ET-1 is elevated in sepsis. The present study investigated whether ET plays a role in sepsis-mediated acute lung injury and whether its expression could be down regulated by blockade of TNF-α in septic lung. Male Wistar rats at 8 weeks of age were administered with either saline or lipopolysaccharide (LPS) at different time points (1, 3, 6 and 10 h) and various tests were then performed. The features of acute lung injury were observed at 1 h after LPS administration, which gradually became severe with time. Systolic and diastolic pressures were reduced just about one hour after LPS administration, whereas pulmonary TNF-α levels were significantly increased at various time points after LPS administration. LPS induced a time-dependent expression of ET-1 and ET(A) receptor in the lungs compared to control, peaking and increasing by 3 fold at 6 h after induction of endotoxemia, whereas levels of ET(B) receptor, which has vasodilating effects, were remarkably down regulated time-dependently. We conclude that time-dependent increase of ET-1 and ET(A) receptor with the down regulation of ET(B) receptor may play a role in the pathogenesis of acute lung injury in endotoxemia. Finally, treatment of LPS-administered rats with TNF-α blocking peptide for three hours significantly suppressed levels of pulmonary ET-1. These data taken together, led us to conclude that differential alteration in ET expression and its receptors may be mediated by TNF-α and may, in part, account for the pathogenesis of acute lung injury in endotoxemia.

The impact of the glycocalyx on microcirculatory oxygen distribution in critical illness

PURPOSE OF REVIEW

Main problems of critical illness and sepsis are an altered oxygen distribution and microvascular dysfunction linked to tissue oedema. This review seeks to analyse the role of the endothelial glycocalyx in this context.

RECENT FINDINGS

The presence of vascular leakage is typically associated with interstitial oedema, arterial hypotension, hypovolaemia and often a bad outcome in patients with systemic inflammation. Early goal-directed therapy provides significant benefits in severe sepsis and septic shock, but is mostly aimed at improving macrohaemodynamics. Recent data suggest that microcirculation also contributes significantly to the pathophysiology of critical illness. In fact, the endothelial glycocalyx plays a major role in vascular barrier competence. According to experimental evidence, it can easily be degraded in the presence of inflammation, but, theoretically also protected by several measures. Clinical studies revealed a positive correlation of the severity of sepsis and ischaemia with mortality, but also with a deterioration of the endothelial glycocalyx. Future investigation should focus on the preservation of this structure and assess microcirculatory variables to judge the success of cardiocirculatory therapy.

SUMMARY

Deterioration of the endothelial glycocalyx initiates a breakdown of the vascular barrier in systemic inflammatory response syndrome and sepsis. Preserving this structure in critical illness might be a future therapeutical goal to improve microcirculatory oxygen distribution.

The cytokine storm and factors determining the sequence and severity of organ dysfunction in multiple organ dysfunction syndrome

Multiple organ dysfunction syndrome (MODS) is a major cause of morbidity and mortality in intensive care units. It is being encountered frequently in critically ill patients owing to advancements in organ-specific supportive technologies to survive the acute phase of severe sepsis and shock. It is now believed that MODS is the result of an inappropriate generalized inflammatory response of the host to a variety of acute insults. The pathologic mechanisms of MODS were reviewed, and factors determining the sequence and severity of organ dysfunction were discussed in depth. In the early phase of MODS, circulating cytokines cause universal endothelium injury in organs. In the later phase of MODS, overexpression of inflammatory mediators in the interstitial space of various organs is considered a main mechanism of parenchyma injury. The difference in constitutive expression and the upregulation of adhesion molecules in vascular beds and the density and potency of intrinsic inflammatory cells in different organs are the key factors determining the sequence and severity of organ dysfunction. By activating the intrinsic inflammatory cell in a distant organ, organ dysfunctions are linked in a positive feedback loop through circulating inflammatory mediators. Antagonists targeted at adhesion molecules may alleviate the severity of endothelial damage. And nonsteroidial anti-inflammatory drugs or steroids administered judiciously in the early phase of MODS may retard the progress of multiple organ failure.

Effectiveness of liposomal-N-acetylcysteine against LPS-induced lung injuries in rodents

Acute lung injury (ALI) and its most severe form, the acute respiratory distress syndrome (ARDS) are frequent complications in critically ill patients and are responsible for significant morbidity and mortality. So far, experimental evidence supports the role of oxidants and oxidative injury in the pathogenesis of ALI/ARDS. In this study, the antioxidant effects of conventional N-acetylcysteine (NAC) and liposomally entrapped N-acetylcysteine (L-NAC) were evaluated in experimental animals challenged with lipopolysaccharide (LPS). Rats were pretreated with empty liposomes, NAC, or L-NAC (25mg/kg body weight, iv); 4h later were challenged with LPS (E. coli, LPS 0111:B4) and sacrificed 20h later. Challenge of saline (SAL)-pretreated animals with LPS resulted in lung injury as evidenced by increases in wet lung weight (edema), increases in lipid peroxidation (marker of oxidative stress), decreases of lung angiotensin-converting enzyme (ACE) (injury marker for pulmonary endothelial cells) and increases in the pro-inflammatory eicosanoids, thromboxane B(2) and leukotriene B(4). The LPS challenge also increased pulmonary myeloperoxidase activity and chloramine concentrations indicative of neutrophil infiltration and activation of the inflammatory response. Pretreatment of animals with L-NAC resulted in significant increases in the levels of non-protein thiols and NAC levels in lung homogenates (p<0.05) and bronchoalveolar lavage fluids (p<0.001), respectively. L-NAC was significantly (p<0.05) more effective than NAC or empty liposomes in attenuating the LPS-induced lung injuries as indicated by the aforementioned injury markers. Our results suggested that the delivery of NAC as a liposomal formulation improved its prophylactic effectiveness against LPS-induced lung injuries.