IL-17A is essential to the development of elastase-induced pulmonary inflammation and emphysema in mice

Gender differences in murine pulmonary responses elicited by cellulose nanocrystals

Background

Cellulose-based materials have been used for centuries to manufacture different goods derived from forestry and agricultural sources. In the growing field of nanocellulose applications, its uniquely engineered properties are instrumental for inventive products coming to competitive markets. Due to their high aspect ratio and stiffness, it is speculated that cellulose nanocrystals (CNC) may cause similar pulmonary toxicity as carbon nanotubes and asbestos, thus posing a potential negative impact on public health and the environment.

Methods

The present study was undertaken to investigate the pulmonary outcomes induced by repeated exposure to respirable CNC. C57BL/6 female and male mice were exposed by pharyngeal aspiration to CNC (40 μg/mouse) 2 times a week for 3 weeks. Several biochemical endpoints and pathophysiological outcomes along with gene expression changes were evaluated and compared in the lungs of male and female mice.

Results

Exposure to respirable CNC caused pulmonary inflammation and damage, induced oxidative stress, elevated TGF-β and collagen levels in lung, and impaired pulmonary functions. Notably, these effects were markedly more pronounced in females compared to male mice. Moreover, sex differences in responses to pulmonary exposure to CNC were also detected at the level of global mRNA expression as well as in inflammatory cytokine/chemokine activity.

Conclusions

Overall, our results indicate that there are considerable differences in responses to respirable CNC based on gender with a higher pulmonary toxicity observed in female mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12989-016-0140-x) contains supplementary material, which is available to authorized users.

IL-17A promotes microglial activation and neuroinflammation in mouse models of intracerebral haemorrhage

Microglial activation is an important contributor to neuroinflammation in intracerebral haemorrhage (ICH). IL-17A has been demonstrated to be involved in neuroinflammatory diseases such as multiple sclerosis. However, the exact mechanism of IL-17A mediated microglial activation in ICH has not been well identified. The purpose of this experiment is to investigate the role of IL-17A in ICH induced microglial activation and neuroinflammation. ICH mice were made by injection of autologous blood model. IL-17A expression and inflammatory factors in perihematomal region, and neurological function of mice were examined after ICH. In addition, IL-17A-neutralizing antibody was utilized to potentially prevent microglial activation and neuroinflammation in ICH mice. The expression of IL-17A, inflammatory factors and microglial activation in perihematomal region were significantly increased, and neurological function of mice was impaired after ICH. In addition, IL-17A Ab prevented ICH-induced cytokine expression, including TNF-α, IL-1β and IL-6, and downstream signaling molecules, including MyD88, TRIF, IκBα, and NF-κBp65 expression, and attenuated microglial activation. IL-17A Ab significantly reduced brain water content and improved neurological function of ICH mice. In conclusion, our results demonstrated that IL-17A was involved in ICH-induced microglial activation and neuroinflammation. IL-17A Ab might also provide a promising therapeutic strategy in ICH.

Emphysema requires the receptor for advanced glycation end-products triggering on structural cells

Pulmonary emphysema is characterized by persistent inflammation and progressive alveolar destruction. The receptor for advanced glycation end-products (RAGE) is a multiligand cell surface receptor reported to be involved in the process of acute alveolar epithelial cell injury. However, studies that address the role of RAGE in pulmonary emphysema are inconclusive. We investigated the role of RAGE in the development of elastase-induced pulmonary inflammation and emphysema in mice. RAGE-sufficient (RAGE(+/+)) mice and RAGE-deficient (RAGE(-/-)) mice were treated with intratracheal elastase on Day 0. Airway inflammation, static lung compliance, lung histology, and the levels of neutrophil-related chemokine and proinflammatory cytokines in bronchoalveolar lavage fluid were determined on Days 4 and 21. Neutrophilia in bronchoalveolar lavage fluid, seen in elastase-treated RAGE(+/+) mice, was reduced in elastase-treated RAGE(-/-) mice on Day 4, and was associated with decreased levels of keratinocyte chemoattractant, macrophage inflammatory protein-2, and IL-1β. Static lung compliance values and emphysematous changes in the lung tissue were decreased in RAGE(-/-) mice compared with RAGE(+/+) mice on Day 21 after elastase treatment. Experiments using irradiated, bone marrow-chimeric mice showed that the mice expressing RAGE on radioresistant structural cells, but not hematopoietic cells, developed elastase-induced neutrophilia and emphysematous change in the lung. In contrast, mice expressing RAGE on hematopoietic cells, but not radioresistant structural cells, showed reduced neutrophilia and emphysematous change in the lung. These data identify the importance of RAGE expressed on lung structural cells in the development of elastase-induced pulmonary inflammation and emphysema. Thus, RAGE represents a novel therapeutic target for preventing pulmonary emphysema.

Cigarette smoke affects IL-17A, IL-17F and IL-17 receptor expression in the lung tissue: Ex vivo and in vitro studies

Cigarette smoke is a risk factor for Chronic Obstructive Pulmonary Disease (COPD). Th-17 cytokines are involved in the pathogenesis of COPD. We aimed to evaluate the role of cigarette smoke on the expression of IL-17A, IL-17F and IL-17R in airways of COPD patients. Epithelial and subepithelial immunoreactivity for IL-17A, IL-17F and IL-17R was assessed in surgical specimens from COPD patients (n=15) and from healthy subjects (HC) (n=10) by immunohistochemistry. In vitro, human epithelial cell line 16HBE and A549 as well as PBMC from normal donors were stimulated with cigarette smoke extract (CSE) (0%, 2.5%, 5%, 10%) to evaluate the IL-17A, IL-17F and IL-17R expression by flow cytometry. Furthermore, rhIL-17A and CSE stimulation was evaluated on proliferation and apoptosis in 16HBE and in A549. In central and distal airways immunoreactivity for IL-17A, IL-17F and IL-17R significantly increased in the epithelium and IL-17A in the subepithelium from COPD than in HC. In distal airway, immunoreactivity for IL-17F increased in the subepithelium of COPD than in HC. IL-17A immunoreactivity positively correlate with IL-17R and total pack years in the epithelium from central and distal airways of COPD patients. In vitro, CSE stimulation significantly increased IL-17F and IL-17R in 16HBE (2.5%) and A549 (5%) while IL-17A and IL-17F in PBMC (10%). IL-17A and CSE stimulation, rather than CSE or rhIL-17A alone, significantly increased proliferation in 16HBE and apoptosis in A549. Cigarette smoke increases Th17 immunity in lung tissue of COPD patients, promoting the mechanism of proliferation and apoptosis in airway epithelial cells.

Nanoparticulate carbon black in cigarette smoke induces DNA cleavage and Th17-mediated emphysema

Chronic inhalation of cigarette smoke is the major cause of sterile inflammation and pulmonary emphysema. The effect of carbon black (CB), a universal constituent of smoke derived from the incomplete combustion of organic material, in smokers and non-smokers is less known. In this study, we show that insoluble nanoparticulate carbon black (nCB) accumulates in human myeloid dendritic cells (mDCs) from emphysematous lung and in CD11c⁺ lung antigen presenting cells (APC) of mice exposed to smoke. Likewise, nCB intranasal administration induced emphysema in mouse lungs. Delivered by smoking or intranasally, nCB persisted indefinitely in mouse lung, activated lung APCs, and promoted T helper 17 cell differentiation through double-stranded DNA break (DSB) and ASC-mediated inflammasome assembly in phagocytes. Increasing the polarity or size of CB mitigated many adverse effects. Thus, nCB causes sterile inflammation, DSB, and emphysema and explains adverse health outcomes seen in smokers while implicating the dangers of nCB exposure in non-smokers.

DOI:http://dx.doi.org/10.7554/eLife.09623.001

Smoking for many years damages the lungs and leads to a disease called emphysema that makes it difficult to breathe and is often deadly. There are thousands of chemicals in cigarette smoke and many of them have been linked to the development of lung cancer, although it has been difficult to pinpoint those that are responsible for smoking-related emphysema. Moreover, cigarette smoke also contains large numbers of small particles and relatively little is known about the role played by these particles in smoking-related disease.

One of the hallmarks of long-term smoking is a blackening of the lung tissue that persists even if someone stops smoking. Previously, little was known about the composition of the substance that causes this blackening, or its significance in the development of emphysema. Now, by studying lung tissue taken from smokers with emphysema, You et al. have shown that this black substance is made of nano-sized particles of a material called carbon black (which is also known as elemental carbon). These nanoparticles are produced by the incomplete combustion of the cigarettes. You et al. also confirmed that nanoparticles of carbon black can cause emphysema in mice.

Closer examination of the lung damage caused by the nanoparticles revealed that they trigger breakages in DNA, which leads to inflammation of the lung. And because the nanoparticles cannot be cleared, they are released into the lung when cells die, which perpetuates lung inflammation and damage.

You et al. then went on to show that nanoparticles of carbon black can be modified in a way that allows them to be cleared from the lungs. Such modifications could potentially protect people who are exposed to carbon black nanoparticles in the environment or in workplaces where carbon black is used, such as factories that produce automobile tires and other rubber products.

DOI:http://dx.doi.org/10.7554/eLife.09623.002

Experimental progressive emphysema in BALB/cJ mice as a model for chronic alveolar destruction in humans

Emphysema, one of the major components of chronic obstructive pulmonary disease (COPD), is characterized by the progressive and irreversible loss of alveolar lung tissue. Even though >80% of COPD cases are associated with cigarette smoking, only a relatively small proportion of smokers develop emphysema, suggesting a potential role for genetic factors in determining individual susceptibility to emphysema. Although strain-dependent effects have been shown in animal models of emphysema, the molecular basis underlying this intrinsic susceptibility is not fully understood. In this present study, we investigated emphysema development using the elastase-induced experimental emphysema model in two commonly used mouse strains, C57BL/6J and BALB/cJ. The results demonstrate that mice with different genetic backgrounds show disparate susceptibility to the development of emphysema. BALB/cJ mice were found to be much more sensitive than C57BL/6J to elastase injury in both a dose-dependent and time-dependent manner, as measured by significantly higher mortality, greater body weight loss, greater decline in lung function, and a greater loss of alveolar tissue. The more susceptible BALB/cJ strain also showed the persistence of inflammatory cells in the lung, especially macrophages and lymphocytes. A comparative gene expression analysis following elastase-induced injury showed BALB/cJ mice had elevated levels of il17A mRNA and a number of classically (M1) and alternatively (M2) activated macrophage genes, whereas the C57BL/6J mice demonstrated augmented levels of interferon-γ. These findings suggest a possible role for these cellular and molecular mediators in modulating the severity of emphysema and highlight the possibility that they might contribute to the heterogeneity observed in clinical emphysema outcomes.

Therapeutic effects of LASSBio-596 in an elastase-induced mouse model of emphysema

Emphysema is an intractable pulmonary disease characterized by an inflammatory process of the airways and lung parenchyma and ongoing remodeling process in an attempt to restore lung structure. There is no effective drug therapy that regenerates lung tissue or prevents the progression of emphysema; current treatment is aimed at symptomatic relief. We hypothesized that LASSBio-596, a molecule with potent anti-inflammatory and immunomodulatory effects, might reduce pulmonary inflammation and remodeling and thus improve lung function in experimental emphysema. Emphysema was induced in BALB/c mice by intratracheal administration of porcine pancreatic elastase (0.1 IU) once weekly during 4 weeks. A control group received saline using the same protocol. After the last instillation of saline or elastase, dimethyl sulfoxide, or LASSBio-596 were administered intraperitoneally, once daily for 8 days. After 24 h, in elastase-induced emphysema animals, LASSBio-596 yielded: (1) decreased mean linear intercept, hyperinflation and collagen fiber content, (2) increased elastic fiber content, (3) reduced number of M1 macrophages, (4) decreased tumor necrosis factor-α, interleukin-1β, interleukin-6, and transforming growth factor-β protein levels in lung tissue, and increased vascular endothelial growth factor. These changes resulted in increased static lung elastance. In conclusion, LASSBio-596 therapy reduced lung inflammation, airspace enlargement, and small airway wall remodeling, thus improving lung function, in this animal model of elastase-induced emphysema.

The need for patient-centred clinical research in idiopathic pulmonary fibrosis

Patient-centredness is an accepted term and is perceived by healthcare professionals to be morally and ethically desirable. We are motivated by the belief that this approach will improve the patient-professional experience of the decision-making process and improve health outcomes. We acknowledge that patients, either as participants or as co-investigators, have positive contributions to make to research. As the idiopathic pulmonary fibrosis (IPF) community enters a new era of clinical research activity we consider that there is greater capacity for patient involvement and partnership.Patient involvement in research can be optimised through collaborations in the research design, study conduct, and dissemination. There is increasing interest in using patient- reported outcomes (PROs), such as health-related quality of life, and symptoms measures to inform decision-making and ensure patient perspectives are taken into account. PROs are an essential component of specialist IPF services, to monitor and improve care delivery and to measure and benchmark performance. In clinical trials, PROs can additionally be used to define entry criteria, evaluate efficacy of an intervention, and evaluate adverse events. We suggest that there is a much wider scope for including patient-centred PROs in clinical research and for creative thought in developing patient co-investigator roles.Participation in research activity requires highly refined decision-making processes, particularly in a condition such as IPF, which has an often unpredictable trajectory. The IPF research landscape has changed and the design and conduct of clinical trials in IPF requires some radical rethinking. It is accepted that involving patients in the role of co-investigators will impact the research questions we ask and result in study designs that are patient-centred. IPF clinical trials have been hindered by the lack of availability of validated, disease-specific questionnaires. A conservative approach appears to have been taken to the inclusion of generic symptom or quality of life measures as PRO endpoints. Thus, the impact of new drugs on the quality of life of research participants demonstrates only minimal benefit. It is time to refocus on a patient-centred approach with regards to the co-investigator role, PRO development, and research participants.

Bilirubin treatment suppresses pulmonary inflammation in a rat model of smoke-induced emphysema

BACKGROUND

Cigarette smoking is a significant risk factor for emphysema, which is characterized by airway inflammation and oxidative damage.

OBJECTIVES

To assess the capacity of bilirubin to protect against smoke-induced emphysema.

METHODS

Smoking status and bilirubin levels were recorded in 58 patients with chronic obstructive pulmonary diseases (COPD) and 71 non-COPD participants. The impact of smoking on serum bilirubin levels and exogenous bilirubin (20 mg/kg/day) on pulmonary injury was assessed in a rat model of smoking-induced emphysema. At sacrifice lung histology, airway leukocyte accumulation and cytokine and chemokine levels in serum, bronchoalveolar lavage fluid (BALF) and lung were analyzed. Oxidative lipid damage and anti-oxidative components was assessed by measuring malondialdehyde, superoxide dismutase (SOD) activity and glutathione.

RESULTS

Total serum bilirubin levels were lower in smokers with or without COPD than non-smoking patients without COPD (P < 0.05). Indirect serum bilirubin levels were lower in COPD patients than patients without COPD (P < 0.05). In rats, cigarette smoke reduced serum total and indirect bilirubin levels. Administration of bilirubin reduced mean linear intercept and mean alveoli area, increased mean alveoli number, reduced macrophage, neutrophil and TNF-α content of BALF, and increased BALF and serum IL-10 level, but lowered local and systemic CCL2, CXCL2, CXCL8 and IL-17 levels. Bilirubin suppressed the smoke-induced systemic and regional oxidative lipid damage associated with increased SOD activity.

CONCLUSION

Bilirubin attenuated smoking-induced pulmonary injury by suppressing inflammatory cell recruitment and pro-inflammatory cytokine secretion, increasing anti-inflammatory cytokine levels, and anti-oxidant SOD activity in a rat model of smoke-induced emphysema.

Contrasting roles for the receptor for advanced glycation end-products on structural cells in allergic airway inflammation vs. airway hyperresponsiveness

The receptor for advanced glycation end-products (RAGE) is a multiligand receptor that belongs to the immunoglobulin superfamily. RAGE is reported to be involved in various inflammatory disorders; however, studies that address the role of RAGE in allergic airway disease are inconclusive. RAGE-sufficient (RAGE+/+) and RAGE-deficient (RAGE-/-) mice were sensitized to ovalbumin, and airway responses were monitored after ovalbumin challenge. RAGE-/- mice showed reduced eosinophilic inflammation and goblet cell metaplasia, lower T helper type 2 (Th2) cytokine production from spleen and peribronchial lymph node mononuclear cells, and lower numbers of group 2 innate lymphoid cells in the lung compared with RAGE+/+ mice following sensitization and challenge. Experiments using irradiated, chimeric mice showed that the mice expressing RAGE on radio-resistant structural cells but not hematopoietic cells developed allergic airway inflammation; however, the mice expressing RAGE on hematopoietic cells but not structural cells showed reduced airway inflammation. In contrast, absence of RAGE expression on structural cells enhanced innate airway hyperresponsiveness (AHR). In the absence of RAGE, increased interleukin (IL)-33 levels in the lung were detected, and blockade of IL-33 receptor ST2 suppressed innate AHR in RAGE-/- mice. These data identify the importance of RAGE expressed on lung structural cells in the development of allergic airway inflammation, T helper type 2 cell activation, and group 2 innate lymphoid cell accumulation in the airways. RAGE on lung structural cells also regulated innate AHR, likely through the IL-33-ST2 pathway. Thus manipulating RAGE represents a novel therapeutic target in controlling allergic airway responses.

Transcriptional profiling and targeted proteomics reveals common molecular changes associated with cigarette smoke-induced lung emphysema development in five susceptible mouse strains

BACKGROUND

Mouse models are useful for studying cigarette smoke (CS)-induced chronic pulmonary pathologies such as lung emphysema. To enhance translation of large-scale omics data from mechanistic studies into pathophysiological changes, we have developed computational tools based on reverse causal reasoning (RCR).

OBJECTIVE

In the present study we applied a systems biology approach leveraging RCR to identify molecular mechanistic explanations of pathophysiological changes associated with CS-induced lung emphysema in susceptible mice.

METHODS

The lung transcriptomes of five mouse models (C57BL/6, ApoE (-/-) , A/J, CD1, and Nrf2 (-/-) ) were analyzed following 5-7 months of CS exposure.

RESULTS

We predicted 39 molecular changes mostly related to inflammatory processes including known key emphysema drivers such as NF-κB and TLR4 signaling, and increased levels of TNF-α, CSF2, and several interleukins. More importantly, RCR predicted potential molecular mechanisms that are less well-established, including increased transcriptional activity of PU.1, STAT1, C/EBP, FOXM1, YY1, and N-COR, and reduced protein abundance of ITGB6 and CFTR. We corroborated several predictions using targeted proteomic approaches, demonstrating increased abundance of CSF2, C/EBPα, C/EBPβ, PU.1, BRCA1, and STAT1.

CONCLUSION

These systems biology-derived candidate mechanisms common to susceptible mouse models may enhance understanding of CS-induced molecular processes underlying emphysema development in mice and their relevancy for human chronic obstructive pulmonary disease.

Activation of C3a receptor is required in cigarette smoke-mediated emphysema

Exposure to cigarette smoke can initiate sterile inflammatory responses in the lung and activate myeloid dendritic cells (mDCs) that induce differentiation of T helper type 1 (Th1) and Th17 cells in the emphysematous lungs. Consumption of complement proteins increases in acute inflammation, but the contribution of complement protein 3 (C3) to chronic cigarette smoke-induced immune responses in the lung is not clear. Here, we show that following chronic exposure to cigarette smoke, C3-deficient (C3(-/-)) mice develop less emphysema and have fewer CD11b(+)CD11c(+) mDCs infiltrating the lungs as compared with wild-type mice. Proteolytic cleavage of C3 by neutrophil elastase releases C3a, which in turn increases the expression of its receptor (C3aR) on lung mDCs. Mice deficient in the C3aR (C3ar(-/-)) partially phenocopy the attenuated responses to chronic smoke observed in C3(-/-) mice. Consistent with a role for C3 in emphysema, C3 and its active fragments are deposited on the lung tissue of smokers with emphysema, and smoke-exposed mice. Together, these findings suggest a critical role for C3a through autocrine/paracrine induction of C3aR in the pathogenesis of cigarette smoke-induced sterile inflammation and provide new therapeutic targets for the treatment of emphysema.

Collagenase mRNA Overexpression and Decreased Extracellular Matrix Components Are Early Events in the Pathogenesis of Emphysema

To describe the progression of parenchymal remodeling and metalloproteinases gene expression in earlier stages of emphysema, mice received porcine pancreatic elastase (PPE) instillation and Control groups received saline solution. After PPE instillation (1, 3, 6 hours, 3 and 21 days) we measured the mean linear intercept, the volume proportion of types I and III collagen, elastin, fibrillin and the MMP-1, -8, -12 and -13 gene expression. We observed an initial decrease in type I (at the 3rd day) and type III collagen (from the 6th hour until the 3rd day), in posterior time points in which we detected increased gene expression for MMP-8 and -13 in PPE groups. After 21 days, the type III collagen fibers increased and the type I collagen values returned to similar values compared to control groups. The MMP-12 gene expression was increased in earlier times (3 and 6 hours) to which we detected a reduced proportion of elastin (3 days) in PPE groups, reinforcing the already established importance of MMP-12 in the breakdown of ECM. Such findings will be useful to better elucidate the alterations in ECM components and the importance of not only metalloelastase but also collagenases in earlier emphysema stages, providing new clues to novel therapeutic targets.

Vasoactive intestinal peptide suppresses macrophage-mediated inflammation by downregulating interleukin-17A expression via PKA- and PKC-dependent pathways

Interleukin (IL)-17A is a pro-inflammatory cytokine that markedly enhances inflammatory responses in the lungs by recruiting neutrophils and interacting with other pro-inflammatory mediators. Reducing the expression of IL-17A could attenuate inflammation in the lungs. However, whether VIP exerts its anti-inflammatory effects by regulating the expression of IL-17A has remained unclear. Here, we show that there is a remarkable increase of IL-17A in bronchoalveolar lavage fluid (BALF) and lung tissue of mice with acute lung injury (ALI). Moreover, lipopolysaccharides (LPS) stimulated elevated expression of IL-17A, which was evident by the enhanced levels of mRNA and protein observed. Furthermore, we also found that VIP inhibited LPS-mediated IL-17A expression in a time- and dose-dependent manner in an in vitro model of ALI and that this process might be mediated via the phosphokinase A (PKA) and phosphokinase C (PKC) pathways. Taken together, our results demonstrated that VIP might be an effective protector during ALI by suppressing IL-17A expression.

Ovary-dependent emphysema augmentation and osteopontin induction in adult female mice

Biological differences between the sexes greatly impact the development and severity of pulmonary disorders such as emphysema. Recent studies have demonstrated crucial roles for osteopontin (OPN, also known as SPP1) in lung inflammation and alveolar destruction in human and experimental emphysema, but the impact of gender on OPN action remains unknown. Here, we report ovary-dependent induction of Opn mRNA with augmentation of experimental emphysema in adult female mice. Both male and female mice developed emphysematous lungs following intra-tracheal administration of porcine pancreatic elastase; however, compared with male mice, female mice developed more severe injury-related inflammation and pathologic alterations of the lungs. Notably, we observed female-specific induction of the Opn gene upon lung injury. Ovariectomy blocked this induction, with attenuation of lung inflammation and alveolar destruction, demonstrating the essential role of ovaries in injury-related Opn induction and augmentation of emphysema in adult female mice. Lastly, pre-treatment of adult female mice with pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid, which blocks ATP-mediated wound response, suppressed Opn mRNA induction upon lung injury, resulting in attenuation of enhanced lung inflammation. Together, our findings define a novel, ovary-dependent mechanism underlying gender-specific augmentation of emphysema through transcriptional control of the Opn gene.

Cytokine inhibition in the treatment of COPD

Cytokines play an important part in many pathobiological processes of chronic obstructive pulmonary disease (COPD), including the chronic inflammatory process, emphysema, and altered innate immune response. Proinflammatory cytokines of potential importance include tumor necrosis factor (TNF)-α, interferon-γ, interleukin (IL)-1β, IL-6, IL-17, IL-18, IL-32, and thymic stromal lymphopoietin (TSLP), and growth factors such as transforming growth factor-β. The current objectives of COPD treatment are to reduce symptoms, and to prevent and reduce the number of exacerbations. While current treatments achieve these goals to a certain extent, preventing the decline in lung function is not currently achievable. In addition, reversal of corticosteroid insensitivity and control of the fibrotic process while reducing the emphysematous process could also be controlled by specific cytokines. The abnormal pathobiological process of COPD may contribute to these fundamental characteristics of COPD, and therefore targeting cytokines involved may be a fruitful endeavor. Although there has been much work that has implicated various cytokines as potentially playing an important role in COPD, there have been very few studies that have examined the effect of specific cytokine blockade in COPD. The two largest studies that have been reported in the literature involve the use of blocking antibody to TNFα and CXCL8 (IL-8), and neither has provided benefit. Blocking the actions of CXCL8 through its CXCR2 receptor blockade was not successful either. Studies of antibodies against IL-17, IL-18, IL-1β, and TSLP are currently either being undertaken or planned. There is a need to carefully phenotype COPD and discover good biomarkers of drug efficacy for each specific target. Specific groups of COPD patients should be targeted with specific anticytokine therapy if there is evidence of high expression of that cytokine and there are features of the clinical expression of COPD that will respond.

Protective effect of dexpanthenol on bleomycin-induced pulmonary fibrosis in rats

Despite extensive studies, there is no effective treatment currently available other than pirfenidone for idiopathic pulmonary fibrosis. A protective effect of pantothenic acid and its derivatives on cell damage produced by oxygen radicals has been reported, but it has not been tested in bleomycin (BLM)--induced pulmonary fibrosis in rats. Therefore, we aimed to investigate the preventive effect of dexpanthenol (Dxp) on pulmonary fibrosis. Thirty-two rats were assigned to four groups as follows: (1) control group, (2) dexpanthenol (Dxp) group; 500 mg/kg Dxp continued intraperitoneally for 14 days, (3) bleomycin (BLM) group; a single intratracheal injection of BLM (2.5 mg/kg body weight in 0.25-ml phosphate buffered saline), and (4) BLM + Dxp-treated group; 500 mg/kg Dxp was administered 1 h before the intratracheal BLM injection and continued for 14 days i.p. The histopathological grades of lung inflammation and collagen deposition, tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and myeloperoxidase (MPO) were measured. BLM provoked inflammation and collagen deposition (p < 0.0001), with a marked increase in myeloperoxidase (MPO) activity resembling increased inflammatory activity (p < 0.0001), which was prevented by Dxp (p < 0.0001, p = 0.02). BLM reduced tissue activities of SOD, GPx, and CAT compared to controls (p = 0.01, 0.03, 0.009). MDA was increased with BLM (p = 0.003). SOD (p = 0.001) and MDA (p = 0.016) levels were improved in group 4. The CAT levels in the BLM + Dxp group were close to those in the control group (p > 0.05). We showed that Dxp significantly prevents BLM-induced lung fibrosis in rats. Further studies are required to evaluate the role of Dxp in the treatment of lung fibrosis.