Bronchoalveolar lavage fluids of ventilated patients with acute lung injury activate NF-κB in alveolar epithelial cell line: role of reactive oxygen/nitrogen species and cytokines

Study on the Correlation Between the Expression of NF-Ƙb in the Alveolar Lavage Fluid of Children with Severe Mycoplasma Pneumoniae Pneumonia, Its Clinical Characteristics, and Cellular Immunity

Objective

This study explored the level of nuclear factor-ƙB (NF-ƙB) in the bronchoalveolar lavage fluid (BALF) of children with severe Mycoplasma Pneumoniae pneumonia (SMPP) and the correlation between NF-ƙB, cellular immunity, and clinical characteristics.

Methods

A total of 41 hospitalized children diagnosed with SMPP were selected and included in the SMPP group, and 13 bronchial foreign bodies (FB) without infection during the same period were included in the FB group. The NF-ƙB in the BALF of participants was detected by enzyme-linked immunosorbent assay. The correlation between NF-ƙB and laboratory findings, cellular immunity, and the clinical features in children with SMPP was analyzed. The differences in chest imaging and bronchoscopy in children with SMPP were observed.

Results

The levels of NF-ƙB were significantly increased in the SMPP group compared with the FB group (P < 0.001). There were correlations between different NF-ƙB pairs in the SMPP group (P < 0.01). Nuclear factor-ƙB (NF-ƙB) correlated with IL-6, the mycoplasma load in BALF, fever peak, length of hospital stay, and sputum suppository (P < 0.05). The higher the intracellular NF-ƙB level in BALF, the lower the CD3+ CD4+ value in peripheral blood (P < 0.05). Intracellular NF-ƙB and total NF-ƙB correlated with pleural effusion, pericardial effusion, and extrapulmonary complications (P < 0.05).

Conclusion

NF-ƙB is involved in airway inflammation changes in children with SMPP. The higher the level of NF-ƙB in the airway, the more severe the clinical manifestations, and the longer the length of hospital stay is likely to be.

Association between inflammatory biomarkers and acute respiratory distress syndrome or acute lung injury risk : A systematic review and meta-analysis

Background

The relationship between acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) and levels of certain inflammatory factors remains controversial. The purpose of this meta-analysis was to summarize the available studies evaluating the association between levels of inflammatory factors and ARDS/ALI incidence.

Methods

We searched the PubMed, EmBase, and Cochrane databases for studies published up to July 2017. For each inflammatory factor, a random effects model was employed to pool results from different studies.

Results

We identified 63 studies that included 6243 patients in our meta-analysis. Overall, the results indicated that the levels of angiopoietin (ANG)-2 (standard mean difference, SMD: 1.34; P < 0.001), interleukin (IL)-1β (SMD: 0.92; P = 0.012), IL‑6 (SMD: 0.66; P = 0.005), and tumor necrosis factor (TNF)-α (SMD: 0.98; P = 0.001) were significantly higher in patients with ARDS/ALI than in unaffected individuals. No significant differences were observed between patients with ARDS/ALI and unaffected individuals in terms of the levels of IL‑8 (SMD: 0.61; P = 0.159), IL-10 (SMD: 1.10; P = 0.231), and plasminogen activator inhibitor (PAI)-1 (SMD: 0.70; P = 0.060).

Conclusions

ARDS/ALI is associated with a significantly elevated levels of ANG‑2, IL-1β, IL‑6, and TNF‑α, but not with IL‑8, IL-10, and PAI‑1 levels.

Supplementary Information

The online version of this article (10.1007/s00508-021-01971-3) contains supplementary material, which is available to authorized users.

High concentrations of ammonia induced cytotoxicity and bronchoconstriction in a precision-cut lung slices rat model

Exposure to high concentrations of ammonia (NH3) can cause life-threatening lung damages. The objective of this study was to establish a translational in vitro model for NH3-induced lung injury. Precision-cut lung slices (PCLS) from rats were exposed to NH3 and toxicological responses and cell viability were quantified by analysis of LDH, WST-1, inflammatory mediators (IL-1β, IL-6, CINC-1, MMP-9, RAGE and IL-18), and by microscopic evaluation of bronchoconstriction induced by electric-field-stimulation (EFS) or methacholine (MCh). Different treatment strategies were assessed to prevent or reverse the damages caused by NH3 using anti-inflammatory, anti-oxidant or neurologically active drugs. Exposure to NH3 caused a concentration-dependent increase in cytotoxicity (LDH/WST-1) and IL-1β release in PCLS medium. None of the treatments reduced cytotoxicity. Deposition of NH3 (24-59 mM) on untreated PCLS elicited an immediate concentration-dependent bronchoconstriction. Unlike MCh, the EFS method did not constrict the airways in PCLS at 5 h after NH3-exposure (47-59 mM). Atropine and TRP-channel antagonists blocked EFS-induced bronchoconstriction but these inhibitors could not block the immediate NH3-induced bronchoconstriction. In conclusion, NH3 exposure caused cytotoxic effects and lung damages in a concentration-dependent manner and this PCLS method offers a way to identify and test new concepts of medical treatments and biomarkers that may be of prognostic value.

Clinical Relevance of the Anti-inflammatory Effects of Roflumilast on Human Bronchus: Potentiation by a Long-Acting Beta-2-Agonist

Background: Roflumilast is an option for treating patients with severe COPD and frequent exacerbations despite optimal therapy with inhaled drugs. The present study focused on whether the phosphodiesterase (PDE) 4 inhibitor roflumilast and its active metabolite roflumilast N-oxide affect the release of tumor necrosis factor (TNF)-α and chemokines by lipopolysaccharide (LPS)-stimulated human bronchial explants. We also investigated the interactions between roflumilast, roflumilast N-oxide and the β₂-agonist formoterol with regard to cytokine release by the bronchial preparations.

Methods: Bronchial explants from resected lungs were incubated with roflumilast, roflumilast N-oxide and/or formoterol and then stimulated with LPS. An ELISA was used to measure levels of TNF-α and chemokines in the culture supernatants.

Results: At a clinically relevant concentration (1 nM), roflumilast N-oxide and roflumilast consistently reduced the release of TNF-α, CCL2, CCL3, CCL4, CCL5 and CXCL9 (but not CXCL1, CXCL5, CXCL8 and IL-6) from human bronchial explants. Formoterol alone decreased the release of TNF-α, CCL2, and CCL3. The combination of formoterol with roflumilast (1 nM) was more potent than roflumilast alone for inhibiting the LPS-induced release of TNF-α, CCL2, CCL3, CCL4, and CXCL9 by the bronchial explants.

Conclusions: At a clinically relevant concentration, roflumilast N-oxide and its parent compound, roflumilast, reduced the LPS-induced production of TNF-α and chemokines involved in monocyte and T-cell recruitment but did not alter the release of chemokines involved in neutrophil recruitment. The combination of formoterol with roflumilast enhanced the individual drugs’ anti-inflammatory effects.

Relationship between oropharyngeal dysphagia, nutritional status, antioxidant vitamins and the inflammatory response in adults and elderly: A cross-sectional study

BACKGROUND & AIM

Oropharyngeal dysphagia (OD) can lead to a deficiency of antioxidant micronutrients. The aim of the present study was to investigate the relation between OD and nutritional status, antioxidant vitamins (β-carotene, vitamin E and C) and serum markers of the inflammatory response [C-reactive protein, myeloperoxidase (MPO), nitric oxide metabolites (NOx), tumor necrosis factor-α, interleukin (IL)-1β and IL-6] in adults and elderly.

METHODS

A cross-sectional study was conducted with 69 individuals: 22 in the control group (CG) and 47 in the OD group (ODG). The ODG was subdivided into ODG-mild = normal oral feeding (OF, n = 14), ODG-moderate (OF-modified, n = 22) and ODG-severe (OF-suspended, n = 11). Associations were investigated using multiple linear regression.

RESULTS

The body mass index (BMI) was higher in the ODG compared to the CG (p = 0.008), independently of sex, age, energy intake (EI) and score on the Functional Independence Measure. BMI was significantly lower in the ODG-severe compared to the ODG-mild (p = 0.012). OD was associated with lower concentrations of β-carotene (p < 0.001) and vitamin C (p < 0.001), independently of sex, age and EI, and higher concentrations of MPO (p = 0.008) and NOx (p = 0.011), independently of sex, age and the presence of comorbidities.

CONCLUSION

Adults and elderly with OD have lower levels of antioxidant vitamins (β-carotene and vitamin C) and a high inflammatory response (MPO and NOx). The evaluation of antioxidant vitamins could be incorporated in nutritional status assessment in this population.

Dapsone as treatment adjunct in ARDS

Multiple pharmacological interventions tested over the last decades have failed to reduce ARDS mortality. This short note recounts past data indicating that (i) neutrophils home along an IL-8 gradient, (ii) in ARDS, massive neutrophil accumulation and degranulation in and along bronchoalveolar spaces contributes to damage and hypoxia, (iii) large increases in IL-8 are one of the chemotaxic signals drawing neutrophils to the ARDS lung, and (iv) old data from dermatology and glioblastoma research showed that the old drug against Hansen’s disease, dapsone, inhibits neutrophils’ chemotaxis to IL-8. Therefore dapsone might lower neutrophils’ contributions to ARDS lung pathology. Dapsone can create methemoglobinemia that although rarely problematic it would be particularly undesirable in ARDS. The common antacid drug cimetidine lowers risk of dapsone related methemoglobinemia and should be given concomitantly.

N-acetyl cysteine protects against chlorine-induced tissue damage in an ex vivo model

High-level concentrations of chlorine (Cl₂) can cause life-threatening lung injuries and the objective in this study was to understand the pathogenesis of short-term sequelae of Cl₂-induced lung injury and to evaluate whether pre-treatment with the antioxidant N-acetyl cysteine (NAC) could counteract these injuries using Cl₂-exposed precision-cut lung slices (PCLS). The lungs of Sprague-Dawley rats were filled with agarose solution and cut into 250 μm-thick slices that were exposed to Cl₂ (20-600 ppm) and incubated for 30 min. The tissue slices were pre-treated with NAC (5-25 mM) before exposure to Cl₂. Toxicological responses were analyzed after 5 h by measurement of LDH, WST-1 and inflammatory mediators (IL-1β, IL-6 and CINC-1) in medium or lung tissue homogenate. Exposure to Cl₂ induced a concentration-dependent cytotoxicity (LDH/WST-1) and IL-1β release in medium. Similar cytokine response was detected in tissue homogenate. Contraction of larger airways was measured using electric-field-stimulation method, 200 ppm and control slices had similar contraction level (39 ± 5%) but in the 400 ppm Cl₂ group, the evoked contraction was smaller (7 ± 3%) possibly due to tissue damage. NAC-treatment improved cell viability and reduced tissue damage and the contraction was similar to control levels (50 ± 11%) in the NAC treated Cl₂-exposed slices. In conclusion, Cl₂ induced a concentration-dependent lung tissue damage that was effectively prevented with pre-treatment with NAC. There is a great need to improve the medical treatment of acute lung injury and this PCLS method offers a way to identify and to test new concepts of treatment of Cl₂-induced lung injuries.

Dioscin alleviates lipopolysaccharide-induced acute lung injury through suppression of TLR4 signaling pathways

Aim: Acute lung injury (ALI) is a life-threatening inflammatory syndrome that lacks an effective therapy. Dioscin, a natural steroid saponin isolated from a variety of herbs, could serve as an anti-inflammatory agent, as suggested in previous reports. The purpose of this study was to explore the effects of dioscin on lipopolysaccharide (LPS)-induced ALI and validate the potential mechanisms.Materials and Methods: An ALI model was induced by intratracheal administration of LPS. Dioscin (20, 40, and 80 mg/kg) was administered intragastrically once daily for seven consecutive days prior to LPS challenge.Results: Our data revealed that dioscin significantly suppressed LPS-induced lung pathological changes, pulmonary capillary permeability, pulmonary edema, inflammatory cell infiltration, myeloperoxidase (MPO) activity, and cytokine production, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and keratinocyte chemoattractant (KC). Moreover, dioscin inhibited LPS-induced nuclear factor-kappaB (NF-κB) activation as well as Toll-like receptor 4 (TLR4) expression.Conclusions: In brief, the results indicated that dioscin alleviates LPS-induced ALI through suppression of TLR4 signaling pathways.

New thiazolidinedione LPSF/GQ-2 inhibits NFκB and MAPK activation in LPS-induced acute lung inflammation

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are responsible for high mortality rates in critical patients. Despite >50 years of intensive research, there is no pharmacologically effective treatment to treat ALI. PPARs agonists, chemically named thiazolidinediones (TZDs) have emerged as potential drugs for the treatment of ALI and ARDS due to their anti-inflammatory efficacy. The present study aims to evaluate the potential anti-inflammatory effects of new TZDs derivatives, LPSF/GQ-2 and LPSF/RA-4, on ALI induced by LPS. BALB/c mice were divided into five groups: 1) Control; 2) LPS intranasal 25 μg; 3) LPSF/GQ-2 30 mg/kg + LPS; 4) LPSF/RA-4 20 mg/kg + LPS; and 5) DEXA 1 mg/Kg + LPS. BALF analyses revealed that LPSF/GQ-2 and LPSF/RA-4 reduced NO levels in BALF and inflammatory cell infiltration induced by LPS. MPO levels were also reduced by the LPSF/GQ-2 and LPSF/RA-4 pre-treatments. In contrast, histopathological analyses showed better tissue protection with LPSF/GQ-2 than DEXA and LPSF/RA-4 groups. Similarly, LPSF/GQ-2 reduced inflammatory markers (IL-1, iNOS, TNFα, IL-1β, IL-6) better than LPSF/RA-4. The LPSF/GQ-2 anti-inflammatory action could be attributed to the inhibition of NFκB, ERK, p38, and PARP pathways. In contrast, LPSF/RA-4 had no effect on the expression of p38, JNK, NFκB. The present study indicates that LPSF/GQ-2 presents a potential therapeutic role as an anti-inflammatory drug for ALI.

Anti-inflammatory effect of stem bark of Paulownia tomentosa Steud. in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and LPS-induced murine model of acute lung injury

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves, bark, and flowers of Paulownia tomentosa Steud. have been widely used as a traditional medicine in East Asia to treat inflammatory and infectious diseases.

AIM OF THE STUDY

We investigated the protective effect of the methanol stem bark extract of P. tomentosa using an animal model of lipopolysaccharide (LPS)-induced acute lung injury (ALI).

MATERIALS AND METHODS

The UPLC Q-TOF-MS profiles for the methanol extract of P. tomentosa stem bark showed that verbascoside and isoverbascoside were the predominant compounds. Raw 264.7 cells were used for inhibitory effects of cytokine production in vitro. C57BL/6N mice were administered intranasally with LPS (10μg/per mouse) to induce ALI. H&E staining was used to evaluate histological changes in the lung.

RESULTS

Treatment with P. tomentosa stem bark extract (PTBE) suppressed the production of IL-6 and TNF-α in LPS-stimulated RAW 264.7 macrophages, and the recruitment of neutrophils and macrophages in the BALF of mice with LPS-induced ALI. PTBE also decreased the levels of reactive oxygen species (ROS) and pro-inflammatory cytokines in the BALF. PTBE reduced the levels of nitric oxide (NO) in the serum and of inducible nitric oxide synthase (iNOS) in the lung of ALI mice. PTBE also attenuated the infiltration of inflammatory cells and the expression of monocyte chemoattractant protein-1 (MCP-1) in the lung. In addition, PTBE suppressed the activation of NF-κB and the reduced expression of superoxide dismutase 3 (SOD3) in the lung.

CONCLUSION

The results suggest that PTBE has a protective effect on LPS-induced ALI.

Therapeutic Mechanistic Studies of ShuFengJieDu Capsule in an Acute Lung Injury Animal Model Using Quantitative Proteomics Technology

ShuFengJieDu capsule (SFJDC), a traditional Chinese medicine (TCM) that contains eight medicinal herbs, has been extensively utilized for the treatment of acute lung injury (ALI) and respiratory infections for more than 30 years in China. SFJDC has also been listed in the official guidelines of the China Food and Drug Administration (CFDA) due to its stable clinical manifestations. However, the underlying mechanism of SFJDC during ALI repair remains unclear. In the present study, we explored the protective and therapeutic mechanisms of SFJDC in a rat model by performing qualitative and label-free quantitative proteomics studies. After establishing lipopolysaccharide (LPS)-induced ALI rat models, we profiled macrophage cells isolated from freshly resected rat lung tissues derived from ALI models and ALI rat lung tissue sections using a high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) shotgun proteomics approach to identify changes in the expression levels of proteins of interest. On the basis of our proteomics results and the results of a protein dysregulation analysis of ALI rat lung tissues and rat lung macrophages, AKT1 was selected as a putative key factor that may play an important role in mediating the effects of SFJDC treatment during ALI progression. Follow-up validation studies demonstrated that AKT1 expression effectively regulates various ALI-related molecules, and Gene Ontology analysis indicated that SFJDC-treated ALI rat macrophages were influenced by AKT1-based networks. Gain- and loss-of-function analyses following lentivirus-AKT1 or lentivirus-si-AKT1 infection in macrophages also indicated that AKT1 was essential for the development of ALI due to its ability to regulate oxidative stress, apoptosis, or inflammatory responses. In summary, SFJDC effectively modulated anti-inflammatory and immunomodulation activity during ALI, potentially due to AKT1 regulation during ALI progression. New insights into SFJDC mechanisms may facilitate the development of novel pharmaceutical strategies to control the expression of inflammatory factors.

The Omega-3 Fatty Acid Docosahexaenoic Acid Modulates Inflammatory Mediator Release in Human Alveolar Cells Exposed to Bronchoalveolar Lavage Fluid of ARDS Patients

BACKGROUND

This study investigated whether the 1 : 2 ω-3/ω-6 ratio may reduce proinflammatory response in human alveolar cells (A549) exposed to an ex vivo inflammatory stimulus (bronchoalveolar lavage fluid (BALF) of acute respiratory distress syndrome (ARDS) patients). Methods. We exposed A549 cells to the BALF collected from 12 ARDS patients. After 18 hours, fatty acids (FA) were added as docosahexaenoic acid (DHA, ω-3) and arachidonic acid (AA, ω-6) in two ratios (1 : 2 or 1 : 7). 24 hours later, in culture supernatants were evaluated cytokines (TNF-α, IL-6, IL-8, and IL-10) and prostaglandins (PGE2 and PGE3) release. The FA percentage content in A549 membrane phospholipids, content of COX-2, level of PPARγ, and NF-κB binding activity were determined.

RESULTS

The 1 : 2 DHA/AA ratio reversed the baseline predominance of ω-6 over ω-3 in the cell membranes (P < 0.001). The proinflammatory cytokine release was reduced by the 1 : 2 ratio (P < 0.01 to <0.001) but was increased by the 1 : 7 ratio (P < 0.01). The 1 : 2 ratio reduced COX-2 and PGE2 (P < 0.001) as well as NF-κB translocation into the nucleus (P < 0.01), while it increased activation of PPARγ and IL-10 release (P < 0.001). Conclusion. This study demonstrated that shifting the FA supply from ω-6 to ω-3 decreased proinflammatory mediator release in human alveolar cells exposed to BALF of ARDS patients.

Administration of microparticles from blood of the lipopolysaccharide-treated rats serves to induce pathologic changes of acute respiratory distress syndrome

This study was conducted to investigate the effect of intratracheal and intravenous administration of microparticles (MPs) on developing acute respiratory distress syndrome (ARDS). The blood MPs from lipopolysaccharide-treated rats were collected and examined by transmission electron microscopy (TEM). Cellular source of the MPs was identified by fluorescent-labeled antibodies after the circulating MPs were delivered to naïve rats. Levels of myeloperoxidase (MPO), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-10 productions in bronchoalveolar lavage fluid (BALF) and plasma were determined 24 h after the rats received intratracheal and intravenous administration of the MPs. Histopathologic examination of lungs was performed by light microscope. A TEM image of MPs showed spherical particles at a variable diameter from 0.1 to 0.5 µm. Endothelial- and leukocyte-derived vesicles were abundant in the investigated samples. Treatment with MPs may lead to significant increases in MPO, TNF-α, IL-1β, and IL-10 productions in BALF and plasma of the rats (all P < 0.001). Morphological observation indicated that alveolar structures were destroyed with a large amount of neutrophil infiltration in the lungs of the MP-treated rats. Perivascular and/or intra-alveolar hemorrhage were serious and hyaline membrane formed in the alveoli. Intratracheal and intravenous approaches to delivery of the circulating MPs to naïve recipient rats may induce ARDS. This presents an inducer of the onset of ARDS and provides potential therapeutic targets for attenuating lung injury.

Diethylcarbamazine inhibits NF-κB activation in acute lung injury induced by carrageenan in mice

Diethylcarbamazine citrate (DEC) is widely used to treat lymphatic filariasis and Tropical Pulmonary Eosinophilia. A number of studies have reported a possible role in the host immune system, but exactly how DEC exerts this effect is still unknown. The present study reports the effects of DEC pretreatment on NF-κB regulation using the pleurisy model induced by carrageenan. Swiss male mice (Mus musculus) were divided into four experimental groups: control (SAL); carrageenan (CAR); diethylcarbamazine (DEC) and curcumin (CUR). The animals were pretreated with DEC (50mg/kg, v.o), CUR (50mg/kg, i.p) or distilled water for three consecutive days before pleurisy. One way analysis of variance (ANOVA) was performed by Tukey post-hoc test, and values were considered statistically significant when p<0.05. DEC pretreatment reduced tissue damage and the production of inflammatory markers, such as NO, iNOS, PGE2, COX-2, and PARP induced by carrageenan. Similarly, a known inhibitor of NF-κB pathway (curcumin) was also able to reduce these parameters. Like curcumin, DEC prevents NF-κB activation by reducing NF-κB p65 phosphorylation and IκBα degradation. DEC prevented NF-κB activation via p38 MAPK, but did not interfere in the ERK pathway in this experimental model. However, further studies should be developed to confirm this hypothesis. These findings suggest that DEC could be a promising drug for inflammatory disorders, especially in pulmonary diseases such as Acute Lung Inflammation, due its high anti-inflammatory potential which prevents NF-κB activation.

Roflumilast inhibits lipopolysaccharide-induced tumor necrosis factor-α and chemokine production by human lung parenchyma

Background

Roflumilast is the first phosphodiesterase-4 (PDE4) inhibitor to have been approved for the treatment of COPD. The anti-inflammatory profile of PDE4 inhibitors has not yet been explored in human lung tissues. We investigated the effects of roflumilast and its active metabolite roflumilast-N-oxide on the lipopolysaccharide (LPS)-induced release of tumor necrosis factor-alpha (TNF-α) and chemokines by human lung parenchymal explants. We also investigated roflumilast’s interaction with the long-acting β₂-agonist formoterol.

Methods

Explants from 25 patients undergoing surgical lung resection were incubated with Roflumilast, Roflumilast-N-oxide and formoterol and stimulated with LPS. Levels of TNF-α, chemokines (in the culture supernatants) and cyclic adenosine monophosphate (in tissue homogenates) were determined with appropriate immunoassays.

Results

Roflumilast and Roflumilast-N-oxide concentration-dependently reduced the release of TNF-α and chemokines CCL2, CCL3, CCL4, CXCL9 and CXCL10 from LPS-stimulated human lung explants, whereas CXCL1, CXCL5 and CXCL8 release was not altered. Formoterol (10 nM) partially decreased the release of the same cytokines and significantly increased the inhibitory effect of roflumilast on the release of the cytokines.

Conclusions

In human lung parenchymal explants, roflumilast and roflumilast-N-oxide reduced the LPS-induced release of TNF-α and chemokines involved in the recruitment of monocytes and T-cells but not those involved in the recruitment of neutrophils. Addition of formoterol to roflumilast provided superior invitro anti-inflammatory activity, which may translate into greater efficacy in COPD.

Molecular biological effects of selective neuronal nitric oxide synthase inhibition in ovine lung injury

Neuronal nitric oxide synthase is critically involved in the pathogenesis of acute lung injury resulting from combined burn and smoke inhalation injury. We hypothesized that 7-nitroindazole, a selective neuronal nitric oxide synthase inhibitor, blocks central molecular mechanisms involved in the pathophysiology of this double-hit insult. Twenty-five adult ewes were surgically prepared and randomly allocated to 1) an uninjured, untreated sham group (n = 7), 2) an injured control group with no treatment (n = 7), 3) an injury group treated with 7-nitroindazole from 1-h postinjury to the remainder of the 24-h study period (n = 7), or 4) a sham-operated group subjected only to 7-nitroindazole to judge the effects in health. The combination injury was associated with twofold increased activity of neuronal nitric oxide synthase and oxidative/nitrosative stress, as indicated by significant increases in plasma nitrate/nitrite concentrations, 3-nitrotyrosine (an indicator of peroxynitrite formation), and malondialdehyde lung tissue content. The presence of systemic inflammation was evidenced by twofold, sixfold, and threefold increases in poly(ADP-ribose) polymerase, IL-8, and myeloperoxidase lung tissue concentrations, respectively (each P < 0.05 vs. sham). These molecular changes were linked to tissue damage, airway obstruction, and pulmonary shunting with deteriorated gas exchange. 7-Nitroindazole blocked, or at least attenuated, all these pathological changes. Our findings suggest 1) that nitric oxide formation derived from increased neuronal nitric oxide synthase activity represents a pivotal reactive agent in the patho-physiology of combined burn and smoke inhalation injury and 2) that selective neuronal nitric oxide synthase inhibition represents a goal-directed approach to attenuate the degree of injury.

Interferon-gamma coordinates CCL3-mediated neutrophil recruitment in vivo

BACKGROUND

We have shown previously that acute infection with the respiratory pathogen, pneumonia virus of mice (PVM), results in local production of the proinflammatory chemokine, CCL3, and that neutrophil recruitment in response to PVM infection is reduced dramatically in CCL3 -/- mice.

RESULTS

In this work, we demonstrate that CCL3-mediated neutrophil recruitment is coordinated by interferon-gamma (IFNgamma). Neutrophil recruitment in response to PVM infection was diminished five-fold in IFNgamma receptor gene-deleted mice, although neutrophils from IFNgammaR -/- mice expressed transcripts for the CCL3 receptor, CCR1 and responded functionally to CCL3 ex vivo. Similarly, in the absence of PVM infection, CCL3 overexpression alone could not elicit neutrophil recruitment in the absence of IFNgamma. Interestingly, although supplemental IFNgamma restored neutrophil recruitment and resulted in a sustained weight loss among CCL3-overexpressing IFNgamma -/- mice, CCL3-mediated neutrophil recruitment alone did not result in the pulmonary edema or respiratory failure characteristic of severe viral infection, suggesting that CCL3 and IFN-gamma together are sufficient to promote neutrophil recruitment but not pathologic activation.

CONCLUSION

Our findings reveal a heretofore unrecognized hierarchical interaction between the IFNgamma and CCL3, which demonstrate that IFNgamma is crucial for CCL3-mediated neutrophil recruitment in vivo.

NF-kappa B activation as a pathological mechanism of septic shock and inflammation

The pathophysiology of sepsis and septic shock involves complex cytokine and inflammatory mediator networks. NF-kappaB activation is a central event leading to the activation of these networks. The role of NF-kappaB in septic pathophysiology and the signal transduction pathways leading to NF-kappaB activation during sepsis have been an area of intensive investigation. NF-kappaB is activated by a variety of pathogens known to cause septic shock syndrome. NF-kappaB activity is markedly increased in every organ studied, both in animal models of septic shock and in human subjects with sepsis. Greater levels of NF-kappaB activity are associated with a higher rate of mortality and worse clinical outcome. NF-kappaB mediates the transcription of exceptional large number of genes, the products of which are known to play important roles in septic pathophysiology. Mice deficient in those NF-kappaB-dependent genes are resistant to the development of septic shock and to septic lethality. More importantly, blockade of NF-kappaB pathway corrects septic abnormalities. Inhibition of NF-kappaB activation restores systemic hypotension, ameliorates septic myocardial dysfunction and vascular derangement, inhibits multiple proinflammatory gene expression, diminishes intravascular coagulation, reduces tissue neutrophil influx, and prevents microvascular endothelial leakage. Inhibition of NF-kappaB activation prevents multiple organ injury and improves survival in rodent models of septic shock. Thus NF-kappaB activation plays a central role in the pathophysiology of septic shock.

Nitric oxide-related products and myeloperoxidase in bronchoalveolar lavage fluids from patients with ALI activate NF-kappa B in alveolar cells and monocytes

An increased production of NO* and peroxynitrite in lungs has been suspected during acute lung injury (ALI) in humans, and recent studies provided evidence for an alveolar production of nitrated compounds. We observed increased concentrations of nitrites/nitrates, nitrated proteins and markers of neutrophil degranulation (myeloperoxidase, elastase and lactoferrine) in the fluids recovered from bronchoalveolar lavage fluids (BALF) of patients with ALI and correlated these changes to the number of neutrophils and the severity of the ALI. We also observed that BALFs stimulated the DNA-binding activity of the nuclear transcription factor kappa B (NF-kappaB) as detected by electrophoretic mobility shift assay in human alveolar cells (A549) and monocytes (THP1). The level of activation of the NF-kappaB-binding activity was correlated to the concentration of nitrated proteins and myeloperoxidase. Furthermore, in vitro studies confirmed that NO*-derived species (peroxynitrite and nitrites) and the neutrophil enzyme myeloperoxidase by themselves increased the activation of NF-kappaB, thereby arguing for an in vivo pathogenetic role of NO*-related products and neutrophil enzymes to human ALI.

Leukocyte activation by malarial pigment

Malarial pigment, a unique hemozoin crystal composed of unit cells of heme dimers, is present in large amounts in circulating monocytes and neutrophils and can persist unchanged in macrophages for several months. In the present study, we investigated the effect of hemozoin not only on macrophages, but also on neutrophils. We used beta-hematin (BH), a chemically synthetic crystal structurally identical to hemozoin, for these studies. In vitro, BH up-regulated the expression of tumor necrosis factor-alpha in whole blood and in isolated peritoneal macrophages, indicating that hemozoin is able to stimulate monocytes. BH stimulated murine peritoneal neutrophils to express macrophage inflammatory protein-2 (MIP-2), a homologue of human interleukin-8 that is used as a marker of neutrophil activation. Injecting BH into the peritoneal cavity resulted in a dose-dependent migration of neutrophils and a high level of myeloperoxidase activity of peritoneal cells. Finally, BH directly induced neutrophil chemotaxis in vitro. Taken together, these results suggest that the malarial pigment hemozoin can activate leukocytes and may participate in the pathology of severe malaria.

The effects of nitric oxide in acute lung injury

Acute lung injury (ALI) is a common clinical problem associated with significant morbidity and mortality. Ongoing clinical and basic research and a greater understanding of the pathophysiology of ALI have not been translated into new anti-inflammatory therapeutic options for patients with ALI, or into a significant improvement in the outcome of ALI. In both animal models and humans with ALI, there is increased endogenous production of nitric oxide (NO) due to enhanced expression and activity of inducible NO synthase (iNOS). This increased presence of iNOS and NO in ALI contributes importantly to the pathophysiology of ALI. However, inhibition of total NO production or selective inhibition of iNOS has not been effective in the treatment of ALI. We have recently suggested that there may be differential effects of NO derived from different cell populations in ALI. This concept of cell-source-specific effects of NO in ALI has potential therapeutic relevance, as targeted iNOS inhibition specifically to key individual cells may be an effective therapeutic approach in patients with ALI. In this paper, we will explore the potential role for endogenous iNOS-derived NO in ALI. We will review the evidence for increased iNOS expression and NO production, the effects of non-selective NOS inhibition, the effects of selective inhibition or deficiency of iNOS, and this concept of cell-source-specific effects of iNOS in both animal models and human ALI.

Exhaled breath condensate cytokine patterns in chronic obstructive pulmonary disease

Differences in cytokine patterns in stable chronic obstructive pulmonary disease (COPD), exacerbated COPD, smokers without apparent COPD, and healthy volunteers should be of interest for pathophysiological and therapeutic reasons. Methods including lavage, biopsy and sputum have been employed to investigate cytokines in the lung. For asystematic comparison, exhaled breath condensate (EBC) appears to be well suited. We investigated healthy volunteers, smokers without apparent COPD, stable and exacerbated COPD patients (+/- inhalative steroids) and finally those whose exacerbation made mechanical ventilation inevitable, for a more complete picture of inflammatory cytokines in COPD. We chose EBC because it is non-invasive and can be used repeatedly in spontaneous breathing individuals and during mechanical ventilation. EBC cytokines (IL-1 beta, IL-6, IL-8, IL-10, IL-12 p 70, TNF-alpha) were assayed from a single sample using a multiplex array test kit. We observed a significant increase of all cytokines in acute exacerbation compared to stable COPD, smokers, and volunteers. Stable COPD and volunteers exhibited only small differences in cytokine pattern with respect to IL-1 beta and IL-12 (P<0.01). Smokers had increased levels of all investigated cytokines (P<0.01) compared to non-smokers and, with the exception of IL-1 beta, to stable COPD. Inhaled steroids resulted in reduced levels of IL-1 beta, IL-6, IL-8, IL-10, and IL-12 (all: P<0.01) in stable COPD (all: ex-smokers) with dose dependency for IL-8, IL-1 beta and IL-12. EBC analysis successfully characterized important differences in stable COPD compared to exacerbation or smoking and non-smoking healthy individuals.

Nuclear factor-kappaB- and glucocorticoid receptor alpha- mediated mechanisms in the regulation of systemic and pulmonary inflammation during sepsis and acute respiratory distress syndrome. Evidence for inflammation-induced target tissue resistance to glucocorticoids

To test the hypothesis that the interaction between nuclear factor-kappaB (NF-kappaB) and glucocorticoid receptor alpha (GRalpha) is a key pathogenetic mechanism regulating the progression of systemic and pulmonary inflammation in sepsis and acute respiratory distress syndrome (ARDS), we used an ex vivo model of systemic inflammation. Naïve peripheral blood leukocytes (PBL) were exposed to longitudinal (days 1-10) plasma samples from ARDS patients divided into three groups based on physiological improvement and clinical outcome by days 7-10: improvers, nonimprovers-survivors, and nonimprovers-nonsurvivors. In a separate group of nonimprovers-survivors, we correlated the severity of lung histopathology with the intensity of NF-kappaB and GRalpha nuclear staining in immunohistochemistry analysis of lung tissue obtained by open lung biopsy. We found that exposure of naïve cells to longitudinal plasma samples led to divergent directions in NF-kappaB and GRalpha activation that reflected the severity of systemic inflammation. Plasma samples from improvers with declining cytokine levels over time elicited a progressive increase in all measured aspects of glucocorticoid (GC)-induced GRalpha-mediated activity (p = 0.0001) and a correspondent reduction in NF-kappaB nuclear binding (p = 0.0001) and transcription of TNF-alpha and IL-1beta (regulated, GRalpha-driven response). In contrast, plasma samples from nonimprovers with sustained elevation in cytokine levels over time elicited only a modest longitudinal increase in GC-GRalpha-mediated activity (p = 0.04) and a progressive increase in NF-kappaB nuclear binding over time (p = 0.0001) that was most striking in nonsurvivors (dysregulated, NF-kappaB-driven response). By days 3-5, no overlap was observed between groups for NF-kappaB and GC-GRalpha nuclear binding. In immunohistochemistry analyses, lung tissues of patients with severe versus mild ARDS had a higher intensity of NF-kappaB nuclear staining (13 +/- 1.3 vs. 7 +/- 2.9; p = 0.01) and a lower ratio of GRalpha:NF-kappaB in nuclear staining (0.5 +/- 0.2 vs. 1.5 +/- 0.2; p = 0.007). In conclusion, we demonstrated that the ability of GC-GRalpha to downregulate NF-kappaB activation is critical for the resolution of systemic and pulmonary inflammation in ARDS. The findings provide a rationale for the use of prolonged GC treatment in early ARDS.