Anti-inflammatory effects of thiazolidinediones in human airway smooth muscle cells

Unraveling the Link between Ιnsulin Resistance and Bronchial Asthma

Evidence from large epidemiological studies has shown that obesity may predispose to increased Th2 inflammation and increase the odds of developing asthma. On the other hand, there is growing evidence suggesting that metabolic dysregulation that occurs with obesity, and more specifically hyperglycemia and insulin resistance, may modify immune cell function and in some degree systemic inflammation. Insulin resistance seldom occurs on its own, and in most cases constitutes a clinical component of metabolic syndrome, along with central obesity and dyslipidemia. Despite that, in some cases, hyperinsulinemia associated with insulin resistance has proven to be a stronger risk factor than body mass in developing asthma. This finding has been supported by recent experimental studies showing that insulin resistance may contribute to airway remodeling, promotion of airway smooth muscle (ASM) contractility and proliferation, increase of airway hyper-responsiveness and release of pro-inflammatory mediators from adipose tissue. All these effects indicate the potential impact of hyperinsulinemia on airway structure and function, suggesting the presence of a specific asthma phenotype with insulin resistance. Epidemiologic studies have found that individuals with severe and uncontrolled asthma have a higher prevalence of glycemic dysfunction, whereas longitudinal studies have linked glycemic dysfunction to an increased risk of asthma exacerbations. Since the components of metabolic syndrome interact with one another so much, it is challenging to identify each one's specific role in asthma. This is why, over the last decade, additional studies have been conducted to determine whether treatment of type 2 diabetes mellitus affects comorbid asthma as shown by the incidence of asthma, asthma control and asthma-related exacerbations. The purpose of this review is to present the mechanism of action, and existing preclinical and clinical data, regarding the effect of insulin resistance in asthma.

Utility of Hypoglycemic Agents to Treat Asthma with Comorbid Obesity

Adults with obesity may develop asthma that is ineffectively controlled by inhaled corticosteroids and long-acting beta-adrenoceptor agonists. Mechanistic and translational studies suggest that metabolic dysregulation that occurs with obesity, particularly hyperglycemia and insulin resistance, contributes to altered immune cell function and low-grade systemic inflammation. Importantly, in these cases, the same proinflammatory cytokines believed to contribute to insulin resistance may also be responsible for airway remodeling and hyperresponsiveness. In the past decade, new research has emerged assessing whether hypoglycemic therapies impact comorbid asthma as reflected by the incidence of asthma, asthma-related emergency department visits, asthma-related hospitalizations, and asthma-related exacerbations. The purpose of this review article is to discuss the mechanism of action, preclinical data, and existing clinical studies regarding the efficacy and safety of hypoglycemic therapies for adults with obesity and comorbid asthma.

A broad look into the future of systemic sclerosis

Systemic sclerosis (SSc) is a systemic autoimmune disease with the key features of inflammation, vasculopathy and fibrosis. This article focussed on emerging fields based on the authors’ current work and expertise. The authors provide a hierarchical structure into the studies of the pathogenesis of SSc starting with the contribution of environmental factors. Regulatory autoantibodies (abs) are discussed, which are parts of the human physiology and are specifically dysregulated in SSc. Abs against the angiotensin II receptor subtype 1 (AT1R) and the endothelin receptor type A (ETAR) are discussed in more detail. Extracellular vesicles are another novel player to possess disease processes. Fibroblasts are a key effector cell in SSc. Therefore, the current review will provide an overview about their plasticity in the phenotype and function. Promising nuclear receptors as key regulators of transcriptional programmes will be introduced as well as epigenetic modifications, which are pivotal to maintain the profibrotic fibroblast phenotype independent of external stimuli. Fibroblasts from SSc patients exhibit a specific signalling and reactivate developmental pathways and stem cell maintenance such as by employing hedgehog and WNT, which promote fibroblast-to-myofibroblast transition and extracellular matrix generation. Pharmacological interventions, although for other indications, are already in clinical use to address pathologic signalling.

Advancing the Adverse Outcome Pathway for PPARγ Inactivation Leading to Pulmonary Fibrosis Using Bradford-Hill Consideration and the Comparative Toxicogenomics Database

Pulmonary fibrosis is regulated by transforming growth factor-β (TGF-β) and peroxisome proliferator-activated receptor-gamma (PPARγ). An adverse outcome pathway (AOP) for PPARγ inactivation leading to pulmonary fibrosis has been previously developed. To advance the development of this AOP, the confidence of the overall AOP was assessed using the Bradford-Hill considerations as per the recommendations from the Organisation for Economic Co-operation and Development (OECD) Users' Handbook. Overall, the essentiality of key events (KEs) and the biological plausibility of key event relationships (KERs) were rated high. In contrast, the empirical support of KERs was found to be moderate. To experimentally evaluate the KERs from the molecular initiating event (MIE) and KE1, PPARγ (MIE) and TGF-β (KE1) inhibitors were used to examine the effects of downstream events following inhibition of their upstream events. PPARγ inhibition (MIE) led to TGF-β activation (KE1), upregulation in vimentin expression (KE3), and an increase in the fibronectin level (KE4). Similarly, activated TGF-β (KE1) led to an increase in vimentin (KE3) and fibronectin expression (KE4). In the database analysis using the Comparative Toxicogenomics Database, 31 genes related to each KE were found to be highly correlated with pulmonary fibrosis, and the top 21 potential stressors were suggested. The AOP for pulmonary fibrosis evaluated in this study will be the basis for the screening of inhaled toxic substances in the environment.

Inhibition of mitoNEET attenuates LPS-induced inflammation and oxidative stress

MitoNEET (mitochondrial protein containing Asn–Glu–Glu–Thr (NEET) sequence) is a 2Fe–2S cluster-containing integral membrane protein that resides in the mitochondrial outer membrane and participates in a redox-sensitive signaling and Fe–S cluster transfer. Thus, mitoNEET is a key regulator of mitochondrial oxidative capacity and iron homeostasis. Moreover, mitochondrial dysfunction and oxidative stress play critical roles in inflammatory diseases such as sepsis. Increased iron levels mediated by mitochondrial dysfunction lead to oxidative damage and generation of reactive oxygen species (ROS). Increasing evidence suggests that targeting mitoNEET to reverse mitochondrial dysfunction deserves further investigation. However, the role of mitoNEET in inflammatory diseases is unknown. Here, we investigated the mechanism of action and function of mitoNEET during lipopolysaccharide (LPS)-induced inflammatory responses in vitro and in vivo. Levels of mitoNEET protein increased during microbial or LPS-induced sepsis. Pharmacological inhibition of mitoNEET using mitoNEET ligand-1 (NL-1) decreased the levels of pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α in animal models of sepsis, as well as LPS-induced inflammatory responses by macrophages in vitro. Inhibition of mitoNEET using NL-1 or mitoNEET shRNA abrogated LPS-induced ROS formation and mitochondrial dysfunction. Furthermore, mitochondrial iron accumulation led to generation of LPS-induced ROS, a process blocked by NL-1 or shRNA. Taken together, these data suggest that mitoNEET could be a key therapeutic molecule that targets mitochondrial dysfunction during inflammatory diseases and sepsis.

PPARγ agonists promote the resolution of myelofibrosis in preclinical models

Myelofibrosis (MF) is a non-BCR-ABL myeloproliferative neoplasm associated with poor outcomes. Current treatment has little effect on the natural history of the disease. MF results from complex interactions between (a) the malignant clone, (b) an inflammatory context, and (c) remodeling of the bone marrow (BM) microenvironment. Each of these points is a potential target of PPARγ activation. Here, we demonstrated the therapeutic potential of PPARγ agonists in resolving MF in 3 mouse models. We showed that PPARγ agonists reduce myeloproliferation, modulate inflammation, and protect the BM stroma in vitro and ex vivo. Activation of PPARγ constitutes a relevant therapeutic target in MF, and our data support the possibility of using PPARγ agonists in clinical practice.

Anti-inflammatory Property of AMP-activated Protein Kinase

BACKGROUND

One of the many debated topics in inflammation research is whether this scenario is really an accelerated form of human wound healing and immunityboosting or a push towards autoimmune diseases. The answer requires a better understanding of the normal inflammatory process, including the molecular pathology underlying the possible outcomes. Exciting recent investigations regarding severe human inflammatory disorders and autoimmune conditions have implicated molecular changes that are also linked to normal immunity, such as triggering factors, switching on and off, the influence of other diseases and faulty stem cell homeostasis, in disease progression and development.

METHODS

We gathered around and collected recent online researches on immunity, inflammation, inflammatory disorders and AMPK. We basically searched PubMed, Scopus and Google Scholar to assemble the studies which were published since 2010.

RESULTS

Our findings suggested that inflammation and related disorders are on the verge and interfere in the treatment of other diseases. AMPK serves as a key component that prevents various kinds of inflammatory signaling. In addition, our table and hypothetical figures may open a new door in inflammation research, which could be a greater therapeutic target for controlling diabetes, obesity, insulin resistance and preventing autoimmune diseases.

CONCLUSION

The relationship between immunity and inflammation becomes easily apparent. Yet, the essence of inflammation turns out to be so startling that the theory may not be instantly established and many possible arguments are raised for its clearance. However, this study might be able to reveal some possible approaches where AMPK can reduce or prevent inflammatory disorders.

Sestrin2 regulates monocyte activation through AMPK-mTOR nexus under high-glucose and dyslipidemic conditions

The vicious cycle between hyperinsulinemia and insulin resistance results in the progression of atherosclerosis in the vessel wall. The complex interaction between hyperglycemia and lipoprotein abnormalities promotes the development of atherogenesis. In the early phase of atherosclerosis, macrophage-derived foam cells play an important role in vascular remodeling. Mechanistic target of rapamycin (mTOR) signaling pathway has been identified to play an essential role in the initiation, progression, and complication of atherosclerosis. Recently sestrin2, an antioxidant, was shown to modulate TOR activity and thereby regulating glucose and lipid metabolism. But the role of sestrin2 in monocyte activation is still not clearly understood. Hence, this study is focussed on investigating the role of sestrin2 in monocyte activation under hyperglycemic and dyslipidemic conditions. High-glucose and oxidized low-density lipoprotein (LDL) treatments mediated proinflammatory cytokine production (M1) with a concomitant decrease in the anti-inflammatory cytokine (M2) levels in human monocytic THP1 cells. Both glucose and oxidized LDL (OxLDL) in a dose and time-dependent manner increased the mTOR activation with a marked reduction in the levels of pAMPK and sestrin2 expression. Both high-glucose and OxLDL treatment increased foam cell formation and adhesion of THP1 cells to endothelial cells. Experiments employing activator or inhibitor of adenosine monophosphate kinase (AMPK) as well as overexpression or silencing of sestrin2 indicated that high-glucose mediated monocyte polarization and adhesion of monocytes to the endothelial cells were appeared to be programmed via sestrin2-AMPK-mTOR nexus. Our results evidently suggest that sestrin2 plays a major role in regulating monocyte activation via the AMPK-mTOR-pathway under diabetic and dyslipidemic conditions and also AMPK regulates sestrin2 in a feedback mechanism.

A review of the anti-inflammatory properties of antidiabetic agents providing protective effects against vascular complications in diabetes

The global prevalence of Type 2 diabetes mellitus and its associated complications are growing rapidly. Although the role of hyperglycemia is well recognized in the pathophysiology of diabetic complications, its exact underlying mechanisms are not fully understood. In this regard, accumulating evidence suggests that the role of inflammation appears pivotal, with studies showing that most diabetic complications are associated with an inflammatory response. Several classes of antidiabetic agents have been introduced for controlling glycemia, with evidence that these pharmacological agents may have modulatory effects on inflammation beyond their glucose-lowering activity. Here we review the latest evidence on the anti-inflammatory effects of commonly used antidiabetic medications and discuss the relevance of these effects on preventing diabetic complications.

TRPC3 overexpression and intervention in airway smooth muscle of ovalbumin-induced hyperresponsiveness and remodeling

Transient receptor potential canonical channel 3 (TRPC3) proteins function as non-voltage-gated Ca²⁺ -permeable channels and play divergent roles in many processes of pathophysiology. The purpose of this study was to determine the relationship between TRPC3 expression and airway hyperresponsiveness and remodeling in ovalbumin-induced asthmatic Kunming mice. Mice were sensitized and challenged by ovalbumin to establish asthmatic model. Hematoxylin-eosin staining, hydroxyproline assay, and isometric tracheal ring force measurement were used to evaluate airway remodeling and hyperresponsiveness in asthmatic mice. Western blot was performed to detect the expression of TRPC3 proteins. MTT assay was used to measure the proliferation of airway smooth muscle cells. TRPC3 protein expression increased in airway smooth muscle of asthmatic mice. GdCl₃ , a nonspecific TRPC blocker, attenuated the contractile force of airway smooth muscle. Fetal bovine serum stimulated airway smooth muscle cells proliferation and augmented TRPC3 protein expression. Both TRPC3 blockade by GdCl₃ or specific TRPC3 antibodies and gene silencing by siRNA inhibited the proliferation of airway smooth muscle cells. In contrast, the current drugs treatment for asthma such as Dexamethasone and Aminophylline had no effects on TRPC3 protein overexpression. Therefore, TRPC3 protein overexpression may be involved in airway smooth muscle hyperresponsiveness and remodeling in asthmatic mice, providing evidence for a new direction of asthma pathogenesis research and a new target for drug intervention.

N-Arylation of ferrocenyl 2,4-thiazolidinedione conjugatesviaa copper-catalysed Chan–Lam cross coupling reaction with aryl boronic acids and their optoelectronic properties

Copper catalysed Chan–LamN-arylation of ferrocenyl 2,4-thiazolidinedione conjugates is described.

Troglitazone, a PPAR-γ agonist, decreases LTC4 concentration in mononuclear cells in patients with asthma

BACKGROUND

Asthma is an inflammatory disorder with multiple mediators involved in the inflammatory response. Despite several attempts, no new anti-inflammatory drugs have been registered for asthma treatment for several years. However, thiazolidinediones, peroxisome proliferator-activated receptor agonists, have demonstrated some anti-inflammatory properties in various experimental settings. The aim of this study was to assess the influence of troglitazone on LTC₄ and 15-HETE concentrations. It also evaluates TNF-induced eotaxin synthesis in peripheral blood mononuclear cells from 14 patients with mild asthma and 13 healthy controls.

METHODS

PBMCs were isolated from the whole blood of the asthmatics and healthy subjects and pretreated with 0.1, 1 or 10μM of Troglitazone. The cells were then exposed to 10^-6M calcium jonophore or 10ng/ml TNF. The production and release of LTC₄, 15-HETE and eotaxin were then assessed.

RESULTS

Troglitazone caused a dose-dependent inhibition in LTC₄ synthesis in both asthmatics and healthy subjects. Troglitazone did not influence 15-HETE or eotaxin production in either asthmatic patients or in healthy individuals.

CONCLUSION

Due to its inhibition of LTC₄ synthesis, troglitazone therapy is an interesting potential therapeutic approach in asthma and other LTC₄ related inflammatory disorders.

Honey is potentially effective in the treatment of atopic dermatitis: Clinical and mechanistic studies

Introduction

As manuka honey (MH) exhibits immunoregulatory and anti‐staphylococcal activities, we aimed to investigate if it could be effective in the treatment of atopic dermatitis (AD).

Methods

Adult volunteers with bilateral AD lesions were asked to apply MH on one site overnight for seven consecutive days and leave the contralateral site untreated as possible. Three Item Severity score was used to evaluate the response. Skin swabs were obtained from both sites before and after treatment to investigate the presence of staphylococci and enterotoxin production. In addition, the ability of MH and its methanolic and hexane extracts to down regulate IL4‐induced CCL26 protein release from HaCaT cells was evaluated by enzyme linked immunosorbent assay. Also, the ability of MH to modulate calcium ionophore‐induced mast cell degranulation was assessed by enzyme immunoassay.

Results

In 14 patients, AD lesions significantly improved post MH treatment versus pre‐treatment as compared to control lesions. No significant changes in the skin staphylococci were observed after day 7, irrespective of honey treatment. Consistent with the clinical observation, MH significantly down regulated IL4‐induced CCL26 release from HaCaT cells in a dose‐dependent manner. This effect was partially lost, though remained significant, when methanolic and hexane extracts of MH were utilized. In addition, mast cell degranulation was significantly inhibited following treatment with MH.

Conclusions

MH is potentially effective in the treatment of AD lesions based on both clinical and cellular studies through different mechanisms. This needs to be confirmed by randomized and controlled clinical trials.

Role of glycogen synthase kinase-3β and PPAR-γ on epithelial-to-mesenchymal transition in DSS-induced colorectal fibrosis

Background

Intestinal fibrosis is characterized by abnormal production and deposition of extracellular matrix (ECM) proteins by activated myofibroblasts. The main progenitor cells of activated myofibroblasts are the fibroblasts and the epithelial cells, the latter through the epithelial-mesenchymal transition (EMT).

Aim

To evaluate the action of the new PPAR-γ modulator, GED-0507-34 Levo (GED) on the expression of EMT associated and regulatory proteins such as TGF-β, Smad3, E-cadherin, Snail, ZEB1, β-catenin, and GSK-3β, in a mouse model of DSS-induced intestinal fibrosis.

Methods

Chronic colitis and fibrosis were induced by oral administration of 2.5% DSS (w/v) for 6 weeks. GW9662 (GW), a selective PPAR-γ inhibitor, was also administered by intraperitoneal injection at the dose of 1 mg/kg/day combined with GED treatment. All drugs were administered at the beginning of the second cycle of DSS (day 12). 65 mice were randomly divided into five groups (H₂O as controls n = 10, H₂O+GED n = 10, DSS n = 15, DSS+GED n = 15, DSS+GED+GW n = 15). The colon was excised for macroscopic examination and histological and morphometric analyses. The level of expression of molecules involved in EMT and fibrosis, like TGF-β, Smad3, E-cadherin, Snail, ZEB1, β-catenin, GSK-3β and PPAR-γ, was assessed by immunohistochemistry, immunofluorescence, western blot and Real Time PCR.

Results

GED improved the DSS-induced chronic colitis and fibrosis. GED was able to reduce the expression of the main fibrosis markers (α-SMA, collagen I-III and fibronectin) as well as the pivotal pro-fibrotic molecules IL-13, TGF-β and Smad3, while it increased the anti-fibrotic PPAR-γ. All these GED effects were nullified by co-administration of GW with GED. Furthermore, GED was able to normalize the expression levels of E-cadherin and β-catenin and upregulated GSK-3β, that are all known to be involved both in EMT and fibrosis.

Conclusions

The DSS-induced intestinal fibrosis was improved by the new PPAR-γ modulator GED-0507-34 Levo through the modulation of EMT mediators and pro-fibrotic molecules and through GSK-3β induction.

Effect of intranasal rosiglitazone on airway inflammation and remodeling in a murine model of chronic asthma

BACKGROUND/AIMS

Asthma is characterized by airway hyperresponsiveness, inflammation, and remodeling. Peroxisome proliferator-activated receptors have been reported to regulate inflammatory responses in many cells. In this study, we examined the effects of intranasal rosiglitazone on airway remodeling in a chronic asthma model.

METHODS

We developed a mouse model of airway remodeling, including smooth muscle thickening, in which ovalbumin (OVA)-sensitized mice were repeatedly exposed to intranasal OVA administration twice per week for 3 months. Mice were treated intranasally with rosiglitazone with or without an antagonist during OVA challenge. We determined airway inflammation and the degree of airway remodeling by smooth muscle actin area and collagen deposition.

RESULTS

Mice chronically exposed to OVA developed sustained eosinophilic airway inflammation, compared with control mice. Additionally, the mice developed features of airway remodeling, including thickening of the peribronchial smooth muscle layer. Administration of rosiglitazone intranasally inhibited the eosinophilic inflammation significantly, and, importantly, airway smooth muscle remodeling in mice chronically exposed to OVA. Expression of Toll-like receptor (TLR)-4 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) was increased in the OVA group and decreased in the rosiglitazone group. Co-treatment with GW9660 (a rosiglitazone antagonist) and rosiglitazone increased the expression of TLR-4 and NF-κB.

CONCLUSIONS

These results suggest that intranasal administration of rosiglitazone can prevent not only air way inf lammation but also air way remodeling associated with chronic allergen challenge. This beneficial effect is mediated by inhibition of TLR-4 and NF-κB pathways.

PPARγ antagonist attenuates mouse immune-mediated bone marrow failure by inhibition of T cell function

Acquired aplastic anemia is an immune-mediated disease, in which T cells target hematopoietic cells; at presentation, the bone marrow is replaced by fat. It was reported that bone marrow adipocytes were negative regulators of hematopoietic microenvironment. To examine the role of adipocytes in bone marrow failure, we investigated peroxisomal proliferator-activated receptor gamma, a key transcription factor in adipogenesis, utilizing an antagonist of this factor called bisphenol-A-diglycidyl-ether. While bisphenol-A-diglycidyl-ether inhibited adipogenesis as expected, it also suppressed T cell infiltration of bone marrow, reduced plasma inflammatory cytokines, decreased expression of multiple inflammasome genes, and ameliorated marrow failure. In vitro, bisphenol-A-diglycidyl-ether suppressed activation and proliferation, and reduced phospholipase C gamma 1 and nuclear factor of activated T-cells 1 expression, as well as inhibiting calcium flux in T cells. The in vivo effect of bisphenol-A-diglycidyl-ether on T cells was confirmed in a second immune-mediated bone marrow failure model, using different strains and non-major histocompatibility antigen mismatched: bisphenol-A-diglycidyl-ether ameliorated marrow failure by inhibition of T cell infiltration of bone marrow. Our data indicate that peroxisomal proliferator-activated receptor gamma antagonists may attenuate murine immune-mediated bone marrow failure, at least in part, by suppression of T cell activation, which might hold implications in the application of peroxisomal proliferator-activated receptor gamma antagonists in immune-mediated pathophysiologies, both in the laboratory and in the clinic. Genetically "fatless" mice developed bone marrow failure with accumulation of marrow adipocytes in our model, even in the absence of body fat, suggesting different mechanisms of systematic and marrow adipogenesis and physiologic versus pathophysiologic fat accumulation.

Rosiglitazone elicits in vitro relaxation in airways and precision cut lung slices from a mouse model of chronic allergic airways disease

Rosiglitazone (RGZ), a peroxisome proliferator-activated receptor-γ (PPARγ) ligand, is a novel dilator of small airways in mouse precision cut lung slices (PCLS). In this study, relaxation to RGZ and β-adrenoceptor agonists were compared in trachea from naïve mice and guinea pigs and trachea and PCLS from a mouse model of chronic allergic airways disease (AAD). Airways were precontracted with methacholine before addition of PPARγ ligands [RGZ, ciglitazone (CGZ), or 15-deoxy-(Δ12,14)-prostaglandin J2 (15-deoxy-PGJ2)] or β-adrenoceptor agonists (isoprenaline and salbutamol). The effects of T0070907 and GW9662 (PPARγ antagonists) or epithelial removal on relaxation were assessed. Changes in force of trachea and lumen area in PCLS were measured using preparations from saline-challenged mice and mice sensitized (days 0 and 14) and challenged with ovalbumin (3 times/wk, 6 wk). RGZ and CGZ elicited complete relaxation with greater efficacy than β-adrenoceptor agonists in mouse airways but not guinea pig trachea, while 15-deoxy-PGJ2 did not mediate bronchodilation. Relaxation to RGZ was not prevented by T0070907 or GW9662 or by epithelial removal. RGZ-induced relaxation was preserved in the trachea and increased in PCLS after ovalbumin-challenge. Although RGZ was less potent than β-adrenoceptor agonists, its effects were additive with salbutamol and isoprenaline and only RGZ maintained potency and full efficacy in maximally contracted airways or after allergen challenge. Acute PPARγ-independent, epithelial-independent airway relaxation to RGZ is resistant to functional antagonism and maintained in both trachea and PCLS from a model of chronic AAD. These novel efficacious actions of RGZ support its therapeutic potential in asthma when responsiveness to β-adrenoceptor agonists is limited.

Thiazolidinediones are associated with a reduced risk of COPD exacerbations

BACKGROUND

Thiazolidinediones (TZDs) are oral antihyperglycemic medications that are selective agonists to peroxisome proliferator-activated receptor gamma and have been shown to have potent anti-inflammatory effects in the lung.

OBJECTIVE

The purpose of this study was to assess whether exposure to TZDs is associated with a decreased risk of chronic obstructive pulmonary disease (COPD) exacerbation.

METHODS

A cohort study was performed by collecting data on all US veterans with diabetes and COPD who were prescribed oral antihyperglycemic medications during from period of October 1, 2005 to September 30, 2007. Patients who had two or more prescriptions for TZDs were compared with patients who had two or more prescriptions for an alternative oral anti-hyperglycemic medication. Multivariable negative binomial regression was performed with adjustment for potential confounding factors. The primary outcome was COPD exacerbations, including both inpatient and outpatient exacerbations.

RESULTS

We identified 7,887 veterans who were exposed to TZD and 42,347 veterans who were exposed to non-TZD oral diabetes medications. COPD exacerbations occurred in 1,258 (16%) of the TZD group and 7,789 (18%) of the non-TZD group. In multivariable negative binomial regression, there was a significant reduction in the expected number of COPD exacerbations among patients who were exposed to TZDs with an incidence rate ratio of 0.86 (95% CI 0.81-0.92).

CONCLUSION

Exposure to TZDs was associated with a small but significant reduction in risk for COPD exacerbation among diabetic patients with COPD.

The Role of PPAR Gamma in Systemic Sclerosis

Fibrosis is recognized as an important feature of many chronic diseases, such as systemic sclerosis (SSc), an autoimmune disease of unknown etiology, characterized by immune dysregulation and vascular injury, followed by progressive fibrosis affecting the skin and multiple internal organs. SSc has a poor prognosis because no therapy has been shown to reverse or arrest the progression of fibrosis, representing a major unmet medical need. Recently, antifibrotic effects of PPARγ ligands have been studied in vitro and in vivo and some theories have emerged leading to new insights. Aberrant PPARγ function seems to be implicated in pathological fibrosis in the skin and lungs. This antifibrotic effect is mainly related to the inhibition of TGF-β/Smad signal transduction but other pathways can be involved. This review focused on recent studies that identified PPARγ as an important novel pathway with critical roles in regulating connective tissue homeostasis, with emphasis on skin and lung fibrosis and its role on systemic sclerosis.

Emodin up-regulates glucose metabolism, decreases lipolysis, and attenuates inflammation in vitro

BACKGROUND

Emodin, the major bioactive component of Rheum palmatum, has many different activities, including antitumor, anti-inflammatory, and antidiabetes effects. Recently, emodin was reported to regulate energy metabolism. In the present study, we further explored the effects of emodin on glucose and lipid metabolism.

METHODS

Differentiated C2C12 myotubes and 3T3-L1 adipocytes were treated with or without different concentrations of emodin (6.25, 12.5, 25 or 50 μmol/L) for different time (1 h, 3 h, 12 h, 24 h or 48 h). Glucose metabolism, oxygen consumption, lactic acid levels, glycerol levels, and inflammation pathways were then evaluated. Cells were collected for quantitative polymerase chain reaction (PCR) and western blot analysis.

RESULTS

Emodin upregulated glucose uptake and consumption in both C2C12 myotubes and 3T3-L1 adipocytes, with glycolysis increased. Furthermore, emodin inhibited lipolysis under basal conditions (as well as in the presence of 10 ng/ml tumor necrosis factor (TNF-)-α in 3T3-L1 adipocytes) and significantly decreased phosphorylated perilipin. Moreover, emodin inhibited the nuclear factor-κB and extracellular signal-regulated kinase pathways in C2C12 myotubes and 3T3-L1 adipocytes.

CONCLUSIONS

Emodin upregulates glucose metabolism, decreases lipolysis, and inhibits inflammation in C2C12 myotubes and 3T3-L1 adipocytes.

Influenza virus A/Anhui/1/2013 (H7N9) replicates efficiently in the upper and lower respiratory tracts of cynomolgus macaques

In March 2013, three fatal human cases of infection with influenza A virus (H7N9) were reported in China. Since then, human cases have been accumulating. Given the public health importance of this virus, we performed a pathogenicity study of the H7N9 virus in the cynomolgus macaque model, focusing on clinical aspects of disease, radiographic, histological, and gene expression profile changes in the upper and lower respiratory tracts, and changes in systemic cytokine and chemokine profiles during infection. Cynomolgus macaques developed transient, mild to severe disease with radiographic evidence of pulmonary infiltration. Virus replicated in the upper as well as lower respiratory tract, with sustained replication in the upper respiratory tract until the end of the experiment at 6 days after inoculation. Virus shedding occurred mainly via the throat. Histopathological changes in the lungs were similar to those observed in humans, albeit less severe, with diffuse alveolar damage, infiltration of polymorphonuclear cells, formation of hyaline membranes, pneumocyte hyperplasia, and fibroproliferative changes. Analysis of gene expression profiles in lung lesions identified pathways involved in tissue damage during H7N9 infection as well as leads for development of therapeutics targeting host responses rather than virus replication. Overall, H7N9 infection was not as severe in cynomolgus macaques as in humans, supporting the possible role of underlying medical complications in disease severity as discussed for human H7N9 infection (H. N. Gao et al., N. Engl. J. Med. 368:2277–2285, 2013, doi:10.1056/NEJMoa1305584).

Influenza A virus H7N9 emerged early in 2013, and human cases have continued to emerge since then. Although H7N9 virus-induced disease in humans is often very severe and even lethal, the majority of reported H7N9 cases occurred in older people and people with underlying medical conditions. To better understand the pathogenicity of this virus, healthy cynomolgus macaques were inoculated with influenza A virus H7N9. Cynomolgus macaques were used as a model because the receptor distribution for H7N9 virus in macaques was recently shown to be more similar to that in humans than that of other frequently used animal models. From comparison with previous studies, we conclude that the emerging H7N9 influenza virus was more pathogenic in cynomolgus macaques than seasonal influenza A viruses and most isolates of the pandemic H1N1 virus but less pathogenic than the 1918 Spanish influenza virus or highly pathogenic avian influenza (HPAI) H5N1 virus.

Obesity and asthma in children: current and future therapeutic options

With the childhood prevalence of obesity and asthma increasing, it is important for pediatric professionals to appreciate that obesity modifies the diagnosis and management of asthma. These disease modifications present challenges to clinical management, including decreased responsiveness to controller therapy and decreased quality of life compared with normal-weight asthmatic children. While consensus guidelines do not currently suggest specific changes in asthma management for obese patients, management of some patients may be improved with consideration of the latest evidence. This article briefly summarizes what is known regarding the complex relationship between obesity and asthma in children, and discusses practical issues associated with the diagnosis and effective clinical management of asthma in obese children. On average, obese patients with asthma do not respond as well to inhaled corticosteroid therapy. Management approaches including weight loss and routine exercise are safe, and may improve important asthma outcomes. Asthma providers should learn to facilitate weight loss for their obese patients. In addition, pharmacologic interventions for weight loss in obese asthma, though not currently recommended, may soon be considered.

Therapeutic potential of anti-IL-1β IgY in guinea pigs with allergic asthma induced by ovalbumin

BACKGROUND

Interleukin-1 beta (IL-1β) plays pivotal roles in the progression of allergic airway inflammation. This study aims to determine whether the blockade of IL-1β can inhibit airway inflammation in guinea pigs with allergic asthma induced by the inhalation of aerosolized ovalbumin (OVA).

METHODS

Healthy guinea pigs treated with saline were used as normal controls (group C). The guinea pigs with allergic asthma induced by the inhalation of aerosolized OVA were randomly divided into three groups: (1) the M group containing negative control animals treated with saline; (2) the Z1 group containing animals treated by the inhalation of atomized 0.1% anti-IL-1β immunoglobulin yolk (IgY); and (3) the Z2 group containing positive control animals that were treated with budesonide. The inflammatory cells in the peripheral blood (PB) and bronchoalveolar lavage fluid (BALF) were evaluated using methylene blue and eosin staining. Cytokine concentrations were measured using an enzyme-linked immunosorbent assay. Pulmonary sections were examined using hematoxylin-eosin staining.

RESULTS

Allergic inflammation and damage to the pulmonary tissues were decreased in the Z1 group compared to the M group. Eosinophils and neutrophils in the PB and BALF were significantly decreased in the Z1 group compared to the M group (P<0.05). Treatment with anti-IL-1β IgY significantly reduced the levels of IL-1β, IL-4, IL-8, IL-13, TNF-α, TGF-β1 and IgE in the BALF (P<0.05).

CONCLUSION

The inhalation of aerosolized anti-IL-1β IgY inhibits pathological responses in the pulmonary tissues of guinea pigs with allergic asthma. The inhibitory activity may be due to the decrease in the numbers of eosinophils and neutrophils and the reduced levels of inflammatory cytokines and IgE in the PB and BALF.

Thiazolidinediones inhibit airway smooth muscle release of the chemokine CXCL10: in vitro comparison with current asthma therapies

BACKGROUND

Activated mast cells are present within airway smooth muscle (ASM) bundles in eosinophilic asthma. ASM production of the chemokine CXCL10 plays a role in their recruitment. Thus the effects of glucocorticoids (fluticasone, budesonide), long-acting β2-agonists (salmeterol, formoterol) and thiazolidinediones (ciglitazone, rosiglitazone) on CXCL10 production by ASM cells (ASMC) from people with and without asthma were investigated in vitro.

METHODS

Confluent serum-deprived cells were treated with the agents before and during cytokine stimulation for 0-24 h. CXCL10 protein/mRNA, IκB-α levels and p65 activity were measured using ELISA, RT PCR, immunoblotting and p65 activity assays respectively. Data were analysed using ANOVA followed by Fisher's post-hoc test.

RESULTS

Fluticasone and/or salmeterol at 1 and 100 nM inhibited CXCL10 release induced by IL-1β and TNF-α, but not IFNγ or all three cytokines (cytomix). The latter was also not affected by budesonide and formoterol. In asthmatic ASMC low salmeterol, but not formoterol, concentrations increased cytomix-induced CXCL10 release and at 0.01 nM enhanced NF-κB activity. Salmeterol 0.1 nM together with fluticasone 0.1 and 10 nM still increased CXCL10 release. The thiazolidinediones ciglitazone and rosiglitazone (at 25 and 100 μM) inhibited cytomix-induced CXCL10 release but these inhibitory effects were not prevented by the PPAR-g antagonist GW9662. Ciglitazone did not affect early NF-κB activity and CXCL10 mRNA production.

CONCLUSIONS

Thus the thiazolidinediones inhibited asthmatic ASMC CXCL10 release under conditions when common asthma therapies were ineffective or enhanced it. They may provide an alternative strategy to reduce mast cell-ASM interactions and restore normal airway physiology in asthma.

Obesity and pulmonary disease: unanswered questions

Obesity is associated with risk of pulmonary disease, and adversely affects lung function. The parallel increase in obesity and asthma suggests the two conditions are linked; indeed, they can worsen each other. Obesity and inadequate asthma control are associated with poor quality of life, and place a high economic burden on public health. Although the obesity-lung interaction is a major issue for basic research and clinical studies, various questions remain unanswered. Do intrauterine and early life factors impact on the development of obesity and lung disease? If so, can this be prevented? Asthma is generally more severe in obese subjects, but is adiposity a driver of a new asthma phenotype that features greater morbidity and mortality, worse control and decreased response to medications? Obese individuals have small lung volumes, hence their airway calibre is reduced and airway resistance is increased. What puzzles physicians is whether peripheral airways undergo remodelling, which would increase bronchoconstriction. Obese asthmatics respond suboptimally to anti-inflammatory treatment, which raises the question: 'what drug for what patient?' Life expectancy is decreased in obesity and in chronic pulmonary disorders, but does obesity protect against or trigger chronic obstructive pulmonary disease? The time has come to find answers to these questions.

PPARγ Ligands Regulate Noncontractile and Contractile Functions of Airway Smooth Muscle: Implications for Asthma Therapy

In asthma, the increase in airway smooth muscle (ASM) can contribute to inflammation, airway wall remodeling and airway hyperresponsiveness (AHR). Targetting peroxisome proliferator-activated receptor γ (PPARγ), a receptor upregulated in ASM in asthmatic airways, may provide a novel approach to regulate these contributions. This review summarises experimental evidence that PPARγ ligands, such as rosiglitazone (RGZ) and pioglitazone (PGZ), inhibit proliferation and inflammatory cytokine production from ASM in vitro. In addition, inhaled administration of these ligands reduces inflammatory cell infiltration and airway remodelling in mouse models of allergen-induced airways disease. PPARγ ligands can also regulate ASM contractility, with acute treatment eliciting relaxation of mouse trachea in vitro through a PPARγ-independent mechanism. Chronic treatment can protect against the loss of bronchodilator sensitivity to β₂-adrenoceptor agonists and inhibit the development of AHR associated with exposure to nicotine in utero or following allergen challenge. Of particular interest, a small clinical trial has shown that oral RGZ treatment improves lung function in smokers with asthma, a group that is generally unresponsive to conventional steroid treatment. These combined findings support further investigation of the potential for PPARγ agonists to target the noncontractile and contractile functions of ASM to improve outcomes for patients with poorly controlled asthma.

Nuclear receptors as modulators of the tumor microenvironment

Over the past several decades of cancer research, the inherent complexity of tumors has become increasingly appreciated. In addition to acquired cell-intrinsic properties, tumor initiation and growth is supported by an abundance of parenchymal, inflammatory, and stromal cell types, which infiltrate and surround the tumor. Accumulating evidence shows that numerous components of this supportive milieu, referred to collectively as the tumor microenvironment, are indeed critical during the process of multistep tumorigenesis. These findings highlight the important interplay between neoplastic cells and tumor-associated cell types, and suggest that therapy should target both neoplastic cells and supportive stromal cells to effectively attenuate tumor growth. The nuclear receptor superfamily encompasses a druggable class of molecules expressed in numerous stromal and parenchymal cell types, whose established physiologic roles suggest their potential as therapeutic and preventive targets in the context of the reactive tumor microenvironment. In this minireview, we discuss recent evidence that tumor-associated inflammation, angiogenesis, and fibrosis can be modulated at the transcriptional level by nuclear receptors and their ligands. As these processes have been widely implicated in cancer initiation, progression, and resistance to current therapy, nuclear receptor ligands targeting the tumor microenvironment may be potent antitumor agents in combination therapies, including for preventing cancer development within high-risk populations.