Anti-inflammatory mechanism of simvastatin in mouse allergic asthma model

Impact of statin therapy on CD40:CD40L signaling: mechanistic insights and therapeutic opportunities

Statins are widely utilized to reduce cholesterol levels, particularly in cardiovascular diseases. They interface with cholesterol synthesis by inhibiting the 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase enzyme. Besides their primary effect, statins demonstrate anti-inflammatory and immune-modulating properties in various diseases, highlighting the pleiotropic effect of these drugs. The CD40:CD40L signaling pathway is considered a prominent inflammatory pathway in multiple diseases, including autoimmune, inflammatory, and cardiovascular diseases. The findings from clinical trials and in vitro and in vivo studies suggest the potential anti-inflammatory effect of statins in modulating the CD40 signaling pathway and downstream inflammatory mediator. Accordingly, as its classic ligand, statins can suppress immune responses in autoimmune diseases by inhibiting CD40 expression and blocking its interaction with CD40L. Additionally, statins affect intracellular signaling and inhibit inflammatory mediator secretion in chronic inflammatory diseases like asthma and autoimmune disorders such as myasthenia gravis, multiple sclerosis, systemic lupus erymanthus, and cardiovascular diseases like atherosclerosis. However, it is essential to note that the anti-inflammatory effect of statins may vary depending on the specific type of statin used. In this study, we aim to explore the potential anti-inflammatory effects of statins in treating inflammatory diseases by examining their role in regulating immune responses, particularly their impact on the CD40:CD40L signaling pathway, through a comprehensive review of existing literature.

Are statins effective in preventing chronic rhinosinusitis? A systematic review and meta-analysis

OBJECTIVES

To evaluate the association between statin use and chronic rhinosinusitis (CRS).

DESIGN AND SETTING

Systematic review and meta-analysis. The methodological quality of studies was assessed using the Newcastle-Ottawa scale.

PARTICIPANTS

Patients with CRS.

MAIN OUTCOME MEASURES

Pooled odds ratios (ORs) with 95% confidence interval (CIs) in analyses of studies that compared the prevalence of CRS, nasal polyp, difference of Lund-Kennedy endoscopic score, Lund-Mackay CT score and Sino-nasal Outcome Test-22.

RESULTS

The analysis included eight studies and 445 465 patients. Patients who used statins were at lower risk for CRS than those who did not (OR = 0.7457, 95% CI = 0.6629-0.8388, p < 0.0001, I2  = 0.0%). Patients with hyperlipidaemia were at higher risk for CRS than those with normal serum levels of lipid (OR = 1.3590, 95% CI = 1.2831-1.4394, p < 0.0001, I2  = 33.3%). However, there were no significant differences in the risk for nasal polyps between CRS patients using statins or not (OR = 1.0931, 95% CI = 0.7860-1.5202, p = 0.5968, I2  = 0.0%). Additionally, statin use was not related to Lund-Kennedy endoscopic scores, Lund-Mackay CT scores or sino-nasal outcome test-22 scores in CRS patients.

CONCLUSION

The risk for CRS is lower in patients who use statins and those without hyperlipidaemia.

Ameliorating the efficacy of galacto-oligosaccharides on ovalumin-induced allergic dermatitis symptoms in Balb/c mice by regulating Th2 immune response and the ecosystem of gut microbiota

In this study, we evaluated the effect of oral administration of galacto-oligosaccharide (GOS), famous biological molecules that are comprised of galactose and lactose, on ovalbumin (OVA)-induced allergic dermatitis. OVA-induced mice were divided into the OVA-administered group (OVA-C), promethazine hydrochloride-administered group (PC), and 100 and 200 mg kg^-1 GOS-administered groups (GL and GH, respectively). GOS administration significantly improved epidermal thickness and decreased CD4⁺ cell numbers. The concentrations of IgE, OVA-specific IgE, and inflammatory cytokines (IL-4, IL-5, and INF-γ) in GH group mice were significantly lower than those in OVA-C group mice. Firmicutes and Bacteroidetes were identified as the major phyla in the intestinal microbiota in mice, and the relative abundance of Deferribacteres was significantly lower in the GH group than in the OVA-C group. Deferribacteraceae and Mucispirillum species were significantly lower in the GH group than in the OVA-C group. The relative abundance of Muribaculum species was significantly lower, but those of Lachnospira and Lactococcus species were significantly higher in the GH group than in the OVA-C group. Our results suggest that the alleviation effect of GOS on allergic dermatitis induced by OVA sensitization was achieved by regulating hypersensitive immune responses by improving the intestinal microbial ecosystem.

HMG-CoA Reductase Inhibitor, Simvastatin Is Effective in Decreasing Degree of Myocarditis by Inhibiting Metalloproteinases Activation

Background: Acute myocarditis often progresses to heart failure because there is no effective, etiology-targeted therapy of this disease. Simvastatin has been shown to be cardioprotective by decreasing matrix metalloproteinases’ (MMPs) activity. The study was designed to determine whether simvastatin inhibits MMPs activity, decreases the severity of inflammation and contractile dysfunction of the heart in experimental autoimmune myocarditis (EAM). Methods: Simvastatin (3 or 30 mg/kg/day) was given to experimental rats with EAM by gastric gavage for 21 days. Then transthoracic echocardiography was performed, MMPs activity and troponin I level were determined and tissue samples were assessed under a light and transmission electron microscope. Results: Hearts treated with simvastatin did not show left ventricular enlargement. As a result of EAM, there was an enhanced activation of MMP-9, which was significantly reduced in the high-dose simvastatin group compared to the low-dose group. It was accompanied by prevention of myofilaments degradation and reduction of severity of inflammation. Conclusions: The cardioprotective effects of simvastatin in the acute phase of EAM are, at least in part, due to its ability to decrease MMP-9 activity and subsequent decline in myofilaments degradation and suppression of inflammation. These effects were achieved in doses equivalent to therapeutic doses in humans.

Gentiopicroside ameliorates ovalbumin-induced airway inflammation in a mouse model of allergic asthma via regulating SIRT1/NF-κB signaling pathway

Allergic asthma is a common airway inflammatory disorder with increasing morbidity and mortality worldwide. Gentiopicroside (GPS) is a secoiridoid glycoside compound that exhibits anti-inflammatory property. However, the effect of GPS on allergic asthma has not been reported yet. In this study, we investigated the role of GPS in a mouse model of ovalbumin (OVA)-induced allergic asthma and explored its potential mechanism. Mice were sensitized with OVA and gavaged with 20, 40, or 80 mg/kg GPS. Administration of GPS decreased lung wet-to-dry weight ratio. Histological analysis of H&E and PAS staining showed that GPS treatment alleviated inflammatory cell infiltration and goblet cell hyperplasia in lung tissue of OVA-sensitized mice. Moreover, GPS inhibited the recruitment of inflammatory cells including total cells, macrophages, eosinophils, lymphocytes and neutrophils and the secretion of T helper type 2 (Th2) cytokines (interleukin (IL)-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) of OVA-sensitized mice in a dose dependent manner. The levels of OVA-specific immunoglobulin E (IgE) and pro-inflammatory tumor necrosis factor (TNF)-α were also attenuated by GPS treatment. Interestingly, GPS upregulated the expression of silent information regulator 1 (SIRT1) while downregulated the expression of acetyl-nuclear factor kappa B (NF-κB) p65 in lung tissue of OVA-sensitized mice. Furthermore, treatment with an SIRT1 inhibitor (EX-527) partially abolished the inhibitory effect of GPS on OVA-induced airway inflammation, suggesting that the anti-inflammation of GPS might be achieved through regulating SIRT1/NF-κB p65 signaling pathway. These findings indicate that GPS might be a novel drug candidate in the treatment of allergic asthma.

Repositioned Drugs for Inflammatory Diseases such as Sepsis, Asthma, and Atopic Dermatitis

The process of drug discovery and drug development consumes billions of dollars to bring a new drug to the market. Drug development is time consuming and sometimes, the failure rates are high. Thus, the pharmaceutical industry is looking for a better option for new drug discovery. Drug repositioning is a good alternative technology that has demonstrated many advantages over de novo drug development, the most important one being shorter drug development timelines. In the last two decades, drug repositioning has made tremendous impact on drug development technologies. In this review, we focus on the recent advances in drug repositioning technologies and discuss the repositioned drugs used for inflammatory diseases such as sepsis, asthma, and atopic dermatitis.

Rosuvastatin suppresses cytokine production and lung inflammation in asthmatic, hyperlipidemic and asthmatic-hyperlipidemic rat models

BACKGROUND

Given the role that T lymphocytes play on the pathogenesis of allergic asthma, drugs targeting Th2 and Th17 cells may be a hopeful therapeutic strategy. This study aimed to evaluate the effect of rosuvastatin treatment on cytokine production and lung inflammation in allergic asthma.

METHODS

The animals were assigned into control (C), asthmatic (A), hyperlipidemic (H), asthmatic-hyperlipidemic (AH), rosuvastatin (40 mg/kg/day intraperitoneally, for 3 weeks)-treated asthmatic (AR), rosuvastatin-treated hyperlipidemic (HR) and rosuvastatin-treated asthmatic-hyperlipidemic (AHR) groups (n = 6 in each group). The levels of IL-4, IFN-γ and IL-17, total and differential WBC counts in bronchoalveolar lavage fluid (BALF), Th1/Th2 balance, and pathological changes were evaluated.

RESULTS

The BALF level of IL-4 in A, H and AH groups, and IL-17A in A and AH groups were significantly higher than that in C group (p < 0.05 to p < 0.001). IFN-γ level and Th1/Th2 balance (IFN‑γ/IL-4 ratio) in A and AH groups were significantly decreased (p < 0.05 to p < 0.01). Inflammatory cells infiltration, muscle hypertrophy and emphysema were also observed in A and AH groups. The BALF levels of IL-4 in AR, HR and AHR groups, IFN-γ level in HR group, and IL-17A level in AR and AHR groups showed a significant improvement compared to that of A, H and AH groups (p < 0.05 to p < 0.001). Rosuvastatin treatment increased Th1/Th2 balance in all treated groups (p < 0.05 to p < 0.01), decreased total WBC counts, neutrophilia, eosinophilia and lung inflammation in AR and AHR groups, and improved muscle hypertrophy and emphysema in AHR group.

CONCLUSIONS

Rosuvastatin treatment improved lung pathological changes by suppression of Th2 and Th17-mediated cytokines which was unrelated to its lipid-lowering activity. Therefore, rosuvastatin might be a candidate immunomodulatory drug for treatment of patients with allergic asthma.

Simvastatin Nanoparticles Reduce Inflammation in LPS-Stimulated Alveolar Macrophages

Simvastatin (SV) is widely used as a lipid-lowering medication that has also been found to have beneficial immunomodulatory effects for treatment of chronic lung diseases. Although its anti-inflammatory activity has been investigated, its underlying mechanisms have not yet been clearly elucidated. In this study, the anti-inflammatory and antioxidant effects and mechanism of simvastatin nanoparticles (SV-NPs) on lipopolysaccharide-stimulated alveolar macrophages (AMs) NR8383 cells were investigated. Quantitative cellular uptake of SV-NPs, the production of inflammatory mediators (interleukin-6, tumor necrosis factor, and monocyte chemoattractant protein-1), and oxidative stress (nitric oxide) were tested. Furthermore, the involvement of the nuclear factor κB (NF-κB) signaling pathway in activation of inflammation in AMs and the efficacy of SV were visualized using immunofluorescence. Results indicated that SV-NPs exhibit a potent inhibitory effect on nitric oxide production and secretion of inflammatory cytokine in inflamed AM, without affecting cell viability. The enhanced anti-inflammatory activity of SV-NPs is likely due to SV-improved chemical-physical stability and higher cellular uptake into AM. The study also indicates that SV targets the inflammatory and oxidative response of AM, through inactivation of the NF-κB signaling pathway, supporting the pharmacological basis of SV for treatment of chronic inflammatory lung diseases.

Intranasal curcumin regulates chronic asthma in mice by modulating NF-ĸB activation and MAPK signaling

BACKGROUND

Curcumin, a natural product found in the plant Curcuma longa, has been reported to have diverse range of molecular targets that influence numerous biochemical and molecular cascades including anti-inflammatory and antioxidant properties.

PURPOSE

The aim of the study was to investigate the therapeutic potential of intranasal curcumin on ovalbumin (OVA)-induced chronic asthma and to elucidate underlying molecular mechanisms.

STUDY DESIGN/METHOD

Mice were sensitized and exposed to 2% OVA aerosol for 2 times in a week for five consecutive weeks to study effect of intranasal curcumin on various MAPK pathway enzymes involved in chronic asthma and its effect on the activation of nuclear factor kB (NF-kB).

RESULTS

Curcumin treatment decreased the ROS level in BALF and nitrite level in blood serum of chronic asthmatic mice. Curcumin treatment had significantly decreased the phosphorylation of JNK, ERK1/2, and p38 and COX-2 expression thereby nuclear factor κB (NF-κB) activation and expression in lung tissues.

CONCLUSION

These results suggest that intranasal curcumin protects against asthma via action on mitogen-activated protein kinase (MAPK)/NF-κB signaling pathways.

Farnesyltransferase Inhibition Exacerbates Eosinophilic Inflammation and Airway Hyperreactivity in Mice with Experimental Asthma: The Complex Roles of Ras GTPase and Farnesylpyrophosphate in Type 2 Allergic Inflammation

Ras, a small GTPase protein, is thought to mediate Th2-dependent eosinophilic inflammation in asthma. Ras requires cell membrane association for its biological activity, and this requires the posttranslational modification of Ras with an isoprenyl group by farnesyltransferase (FTase) or geranylgeranyltransferase (GGTase). We hypothesized that inhibition of FTase using FTase inhibitor (FTI)-277 would attenuate allergic asthma by depleting membrane-associated Ras. We used the OVA mouse model of allergic inflammation and human airway epithelial (HBE1) cells to determine the role of FTase in inflammatory cell recruitment. BALB/c mice were first sensitized then exposed to 1% OVA aerosol or filtered air, and half were injected daily with FTI-277 (20 mg/kg per day). Treatment of mice with FTI-277 had no significant effect on lung membrane-anchored Ras, Ras protein levels, or Ras GTPase activity. In OVA-exposed mice, FTI-277 treatment increased eosinophilic inflammation, goblet cell hyperplasia, and airway hyperreactivity. Human bronchial epithelial (HBE1) cells were pretreated with 5, 10, or 20 μM FTI-277 prior to and during 12 h IL-13 (20 ng/ml) stimulation. In HBE1 cells, FTase inhibition with FTI-277 had no significant effect on IL-13-induced STAT6 phosphorylation, eotaxin-3 peptide secretion, or Ras translocation. However, addition of exogenous FPP unexpectedly augmented IL-13-induced STAT6 phosphorylation and eotaxin-3 secretion from HBE1 cells without affecting Ras translocation. Pharmacological inhibition of FTase exacerbates allergic asthma, suggesting a protective role for FTase or possibly Ras farnesylation. FPP synergistically augments epithelial eotaxin-3 secretion, indicating a novel Ras-independent farnesylation mechanism or direct FPP effect that promotes epithelial eotaxin-3 production in allergic asthma.

Innovations in asthma therapy: is there a role for inhaled statins?

INTRODUCTION

Asthma manifests as chronic airflow obstruction with persistent inflammation and airway hyperresponsiveness. The immunomodulatory and anti-inflammatory properties of the HMG-CoA reductase (HMGCR) inhibitors (a.k.a. statins), suggest a therapeutic role in chronic inflammatory lung diseases. However, despite positive laboratory investigations and promising epidemiological data, clinical trials using statins for the treatment of asthma have yielded conflicting results. Inadequate statin levels in the airway compartment could explain these findings. Areas covered: HMGCR is in the mevalonate (MA) pathway and MA signaling is fundamental to lung biology and asthma. This article will discuss clinical trials of oral statins in asthma, review lab investigations relevant to the systemic versus inhaled administration of statins, address the advantages and disadvantages of inhaled statins, and answer the question: is there a role for inhaled statins in the treatment of asthma? Expert commentary: If ongoing investigations show that oral administration of statins has no clear clinical benefits, then repurposing statins for delivery via inhalation is a logical next step. Inhalation of statins bypasses first-pass metabolism by the liver, and therefore, allows for delivery of significantly lower doses to the airways at greater potency. Statins could become the next major class of novel inhalers for the treatment of asthma.

Serum lipoproteins are not associated with the severity of asthma

BACKGROUND

Asthma is a chronic inflammatory disorder of the bronchi with a complicated and largely unknown pathogenesis. In this context, an emerging role is attributed to the apolipoproteins which serve as structural components of plasma lipoproteins. Low density lipoproteins (LDL) may be involved in the inflammatory pathways of the asthmatic airways; in particular, small dense LDL (sdLDL) particles were associated with increased oxidative susceptibility compared to medium and large sized LDL. In our previous study, we found a positive correlation between forced expiratory volume 1 s (FEV₁) % predicted and larger LDL particles (LDL-1), and an inverse correlation between FEV₁% predicted and sdLDL (LDL-3) in mild, untreated asthmatics. Although LDL appear to be important modulators of inflammation, data on their clinical implications are still lacking.

OBJECTIVE

The aim of the study is to investigate whether LDL subclasses correlate with the severity of asthma, assuming that the atherogenic and most pro-inflammatory LDL contribute to ignite and perpetuate the airway inflammatory processes.

METHODS

The study was conducted in one visit, and included clinical and lung functional assessments, as well as measurements of serum concentrations of the LDL subclasses. Non-denaturing, linear polyacrylamide gel electrophoresis was used to separate and measure LDL subclasses, with the LipoPrint^© System (Quantimetrix Corporation, Redondo Beach, CA, USA). LDL subclasses were distributed as seven bands (LDL-1 to LDL-7), LDL-1 and -2 being defined as large LDL (least pro-inflammatory), and LDL-3 to 7 defined as sdLDL (most pro-inflammatory).

RESULTS

70 asthmatics under inhaled treatment (M/F: 35/35) were enrolled; 10 healthy subjects (M/F: 3/7) served as controls. In the asthmatic group, FEV₁% predicted was 81 ± 22% (mean ± SD), vital capacity (VC) % predicted was 97 ± 18%, and FEV₁/FVC was 0.68 ± 0.1. The mean asthma control test (ACT) score was 18 ± 5. LDL-1 were significantly lower in asthmatics as compared to controls (18 ± 4% vs. 22 ± 4%, p = 0.008). On the contrary, LDL-2 (12 ± 4% vs. 12 ± 5%) and LDL-3 (3 ± 3% vs. 2 ± 2%) were not statistically different between the two groups; smaller subclasses were undetectable. To comply with the design of the study, subjects were classified according to their degree of severity into the 5 Global Initiative for Asthma (GINA) steps: Step 1 (M/F: 4/3, 44 ± 12 yrs), Step 2 (M/F: 1/2, 37 ± 11 yrs), Step 3 (M/F: 12/7, 47 ± 12 yrs), Step 4 (M/F: 8/15, 54 ± 12 yrs), and Step 5 (M/F: 7/9, 56 ± 9 yrs). None of the LDL subclasses showed significant differences between classes of severity: LDL-1 were 16.1 ± 5.6% in Step 1, 18 ± 2.8% in Step 2, 16.7 ± 3.7% in Step 3, 18 ± 3.3% in Step 4, and 19.5 ± 3.2% in Step 5 (p = NS); LDL2 were 14 ± 3.6%, 15 ± 3.4%, 12.4 ± 5.3%, 12.7 ± 4.4% and 11.3 ± 4.2%, respectively (p = NS); LDL3 were 5 ± 5.2%, 4.4 ± 2.6%, 3.3 ± 3.6%, 3.2 ± 2.6% and 2.4 ± 1.8%, p = NS. Finally, no relationship was detected between LDL subclasses and lung function parameters as well as the ACT scores.

CONCLUSIONS

The current findings confirm a role of LDL as a potential biomarker in the diagnostic process for asthma, and suggest that LDL cannot be used as marker of severity of the disease.

Prophylactic benefits of systemically delivered simvastatin treatment in a house dust mite challenged murine model of allergic asthma

BACKGROUND AND PURPOSE

Systemically delivered statins can blunt airway inflammation in ovalbumin-challenged mice. However, in asthma clinical trials the beneficial effects of introducing oral statins are not compelling. We have invetigated this discrepancy using a clinically relevant murine model of allergic asthma, and by including a prophylactic study arm.

EXPERIMENTAL APPROACH

Adult mice were: 1) challenged with house dust mite (HDM) alone or with subcutaneous (s.c.) simvastatin for two weeks; or 2) also treated with simvastatin for one week prior to HDM challenge. We assayed lung function, inflammatory cell influx and cytokine profile, goblet cell abundance, and simvastatin concentration in serum, lung lavage and tissue.

KEY RESULTS

Ultrahigh performance liquid chromatography-tandem mass spectrometry revealed that pharmacologically active simvastatin reached peak serum concentration after 8 h, but declined rapidly. Prophylactic treatment doubled peak serum simvastatin and repeated s.c. delivery established stable serum levels, but simvastatin was undetectable in the lungs. Both simvastatin treatment arms suppressed indices of HDM-induced airway inflammation and goblet cell hyperplasia, but this was significantly greater with prophylactic therapy, in particular, inhibition of neutrophil and eosinophil influx, and cytokine accumulation. Conversely, neither acute nor prophylactic delivery of simvastatin prevented HDM challenge-induced airway hyperreactivity.

CONCLUSION AND IMPLICATIONS

Systemically administered simvastatin accumulates in the blood, but not in lung tissues, and reduces leukocyte influx and associated lung inflammation. Prophylactic therapy has the greatest anti-inflammatory effects, but as observed in human clinical trials, systemic simvastatin therapy does not prevent allergic airway hyperreactivity.

Anti-inflammatory effects of embelin in A549 cells and human asthmatic airway epithelial tissues

OBJECTIVE

Allergic asthma is the most common type in asthma, which is defined as a chronic inflammatory disease of the lung. In this study, we investigated whether embelin (Emb), the major component of Ardisia japonica BL. (AJB), exhibits anti-inflammatory effects on allergic asthma via inhibition of NF-κB activity using A549 cells and asthmatic airway epithelial tissues.

METHODS

Inflammation was induced in A549 cells, a human airway epithelial cell line, by IL-1β (10 ng/ml) treatment for 4 h. The effects of Emb on NF-κB activity and COX-2 protein expression in inflamed airway epithelial cells and human asthmatic airway epithelial tissues were analyzed via western blot. The secretion levels of NF-κB-mediated cytokines/chemokines, including IL-4, 6, 9, 13, TNF-α and eotaxin, were measured by a multiplex assay.

RESULTS

Emb significantly blocked NF-κB activity in IL-1β-treated A549 cells and human asthmatic airway epithelial tissues. COX-2 expression was also reduced in both IL-1β-treated A549 cells and asthmatic tissues Emb application. Emb significantly reduced the secretion of IL-4, IL-6 and eotaxin in human asthmatic airway epithelial tissues by inhibiting activity of NF-κB.

CONCLUSIONS

The results of this study suggest that Emb may be used as an anti-inflammatory agent via inhibition of NF-κB and related cytokines.

Inhaled simvastatin nanoparticles for inflammatory lung disease

Aim: Current inhaled treatments are not adequate to treat all lung diseases. In this study, a promising nanotechnology has been developed to deliver a potential anti-inflammatory and muco-inhibitory compound, simvastatin, for treatment of inflammatory lung diseases via inhalation. Materials & methods: Simvastatin nanoparticles (SV-NPs) encapsulated with poly(lactic-co-glycolic) acid were fabricated using the solvent and anti-solvent precipitation method. Results: SV-NPs were found to be stable up to 9 months at 4°C in a freeze-dried form prior to reconstitution. The amount of mucus produced was significantly reduced after SV-NPs treatment on inflammation epithelial cell models and were effective in suppressing the proinflammatory marker expression. Conclusion: This study suggests that SV-NPs nebulization could potentially be used for the treatment of chronic pulmonary diseases.

Anti‑inflammatory effects of dihydromyricetin in a mouse model of asthma

Dihydromyricetin (DHM) is a plant flavonoid and is the primary active ingredient isolated from the medicinal herb, Ampelopsis grossedentata. DHM has been shown to possess various pharmacological activities, including anti-inflammatory effects. However, the possible role of DHM in asthma treatment remains to be elucidated. The present study aimed to investigate its anti-inflammatory properties in mice with symptoms of allergic asthma. The C57BL/6 mice were sensitized and challenged with ovalbumin (OVA) to induce asthma. DHM or phosphate-buffered saline treatment was administered 1 h prior to the OVA challenge. The levels of interleukin (IL)-4, IL-5 and IL-13 in the bronchoalveolar lavage (BAL) fluid were measured by enzyme-linked immunosorbent assay (ELISA), and OVA-specific serum IgE and IgG1 levels were also determined by ELISA. Histopathological staining was performed to evaluate the infiltration of inflammatory cells into the BAL fluid, lung tissues and goblet cell hyperplasia. DHM treatment significantly reduced the total number of inflammatory cells, including eosinophils, neutrophils, lymphocytes and macrophages, in the BAL fluid. DHM also reduced the levels of IL-4, IL-5 and IL-13 in the BAL fluid, and reduced the secretion of OVA-specific IgE and IgG1 in the serum. The histological staining demonstrated that DHM treatment effectively suppressed the OVA-induced inflammatory cells in the lung tissues and in the mucus hypersecreted by goblet cells in the airway. These results showed that DHM had a potent anti-inflammatory effect in an OVA-induced mouse model of asthma, offering potential as an anti-inflammatory agent for the treatment of asthma.

Examining the role of ABC lipid transporters in pulmonary lipid homeostasis and inflammation

Respiratory diseases including asthma and chronic obstructive pulmonary disease (COPD) are characterised by excessive and persistent inflammation. Current treatments are often inadequate for symptom and disease control, and hence new therapies are warranted. Recent emerging research has implicated dyslipidaemia in pulmonary inflammation. Three ATP-binding cassette (ABC) transporters are found in the mammalian lung – ABCA1, ABCG1 and ABCA3 – that are involved in movement of cholesterol and phospholipids from lung cells. The aim of this review is to corroborate the current evidence for the role of ABC lipid transporters in pulmonary lipid homeostasis and inflammation. Here, we summarise results from murine knockout studies, human diseases associated with ABC transporter mutations, and in vitro studies. Disruption to ABC transporter activity results in lipid accumulation and elevated levels of inflammatory cytokines in lung tissue. Furthermore, these ABC-knockout mice exhibit signs of respiratory distress. ABC lipid transporters appear to have a crucial and protective role in the lung. However, our knowledge of the underlying molecular mechanisms for these benefits requires further attention. Understanding the relationship between cholesterol and inflammation in the lung, and the role that ABC transporters play in this may illuminate new pathways to target for the treatment of inflammatory lung diseases.

Increase of Frequency and Modulation of Phenotype of Regulatory T Cells by Atorvastatin Is Associated with Decreased Lung Inflammatory Cell Infiltration in a Murine Model of Acute Allergic Asthma

Regulatory T cells (Tregs) play an important role by controlling allergic inflammation of airways. Recently, it has been shown that statins have immunomodulatory properties, probably mediated by their effects on Tregs. Therefore, we evaluated the in vivo effect of atorvastatin (ATV) on Tregs and its association with the inflammatory process in a model of allergic asthma. BALB/c mice were sensitized with ovalbumin (OVA) and then challenged with intranasal OVA. ATV (40 mg/kg) was delivered by daily intraperitoneal injection for 7 or 15 days before each OVA challenge. ATV treatment for 7 days increased the frequency of Tregs in mediastinal lymph nodes (MLN) and the interleukin (IL)-10 in lungs. After 15 days of treatment, ATV increased the percentage of glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR+) and programmed cell death protein 1 (PD-1+) Tregs in the lung, without enhancing their suppressive activity, but also increased the percentage of conventional T cells expressing GITR+, PD1+, and OX-40 (tumor necrosis factor receptor superfamily member 4). Although no significant changes were observed in the number of inflammatory cells in the bronchoalveolar lavage (BAL), OVA-specific immunoglobulin E in the serum, and type 2 helper (Th2) cytokines in the lungs, there was a significant decrease of peribronchial inflammation that negatively correlated with the Tregs in MLN and the concentration of IL-10 in the lung. These results suggest that ATV has an immunomodulatory role possibly mediated by their effects on Tregs, which could contribute to the control of inflammation during allergic asthma. Further studies are necessary to elucidate the contribution of Treg to immunomodulatory action of statins in the context of allergic asthma.

Evaluation of Simvastatin and Bone Marrow-Derived Mesenchymal Stem Cell Combination Therapy on Airway Remodeling in a Mouse Asthma Model

INTRODUCTION

The effect of bone marrow-derived mesenchymal stem cells (BMSCs) on asthma treatment was shown in our previous study. Several studies have shown the effect of statins on BMSC preservation and migration to sites of inflammation. In this study, the effects of simvastatin and BMSC combination therapy in an ovalbumin-induced asthma model in mouse were examined.

METHODS

Four groups of BALB/c mice were studied including control group (animals were not sensitized), asthma group (animals were sensitized by ovalbumin), asthma + simvastatin group (asthmatic animals were treated with simvastatin), and asthma + BMSC + simvastatin group (asthmatic animals were treated with simvastatin and BMSCs). BMSCs were isolated, characterized, labeled with BrdU, and transferred into asthmatic mice. BMSC migration, airways histopathology, and total and differential white blood cell (WBC) count in bronchoalveolar lavage (BAL) fluid were evaluated.

RESULTS

A significant increase in the number of BrdU-BMSCs was found in the lungs of mice treated with simvastatin + BMSCs compared to mice treated with BMSCs. The histopathological changes, BAL total WBC counts, and the percentage of neutrophils and eosinophils were increased in asthma group compared to the control group. Treatment with simvastatin significantly decreased airway inflammation and inflammatory cell infiltration. Combination therapy improved all measured parameters higher than simvastatin. Goblet cell hyperplasia and subepithelial fibrosis were also decreased in combination therapy group.

CONCLUSION

These results indicated that simvastatin and BMSC combination therapy was superior to simvastatin therapy and BMSC therapy alone in reduction of airway remodeling and lung inflammation in the ovalbumin-induced asthma model in mouse.

Role of selective blocking of bradykinin receptor subtypes in attenuating allergic airway inflammation in guinea pigs

The present study was designed to evaluate the potential role of bradykinin antagonists (R-715; bradykinin B1 receptor antagonist and icatibant; bradykinin B2 receptor antagonist) in treatment of allergic airway inflammation in comparison to dexamethasone and montelukast. R-715 as dexamethasone significantly decreased peribronchial leukocyte infiltration, bronchoalveolar lavage fluid (BALF) albumin and interleukin 1β as well as serum OVA-specific IgE level. Also, R-715 like montelukast significantly decreased BALF cell count (total and eosinophils). Icatibant showed negative results. The current findings suggest that selective bradykinin B1 receptor antagonists may have the therapeutic potential for the treatment of allergic airway inflammation.

Understanding migraine: Potential role of neurogenic inflammation

Neurogenic inflammation, a well-defined pathophysiologial process is characterized by the release of potent vasoactive neuropeptides, predominantly calcitonin gene-related peptide (CGRP), substance P (SP), and neurokinin A from activated peripheral nociceptive sensory nerve terminals (usually C and A delta-fibers). These peptides lead to a cascade of inflammatory tissue responses including arteriolar vasodilation, plasma protein extravasation, and degranulation of mast cells in their peripheral target tissue. Neurogenic inflammatory processes have long been implicated as a possible mechanism involved in the pathophysiology of various human diseases of the nervous system, respiratory system, gastrointestinal tract, urogenital tract, and skin. The recent development of several innovative experimental migraine models has provided evidence suggestive of the involvement of neuropeptides (SP, neurokinin A, and CGRP) in migraine headache. Antidromic stimulation of nociceptive fibers of the trigeminal nerve resulted in a neurogenic inflammatory response with marked increase in plasma protein extravasation from dural blood vessels by the release of various sensory neuropeptides. Several clinically effective abortive antimigraine medications, such as ergots and triptans, have been shown to attenuate the release of neuropeptide and neurogenic plasma protein extravasation. These findings provide support for the validity of using animal models to investigate mechanisms of neurogenic inflammation in migraine. These also further strengthen the notion of migraine being a neuroinflammatory disease. In the clinical context, there is a paucity of knowledge and awareness among physicians regarding the role of neurogenic inflammation in migraine. Improved understanding of the molecular biology, pharmacology, and pathophysiology of neurogenic inflammation may provide the practitioner the context-specific feedback to identify the novel and most effective therapeutic approach to treatment. With this objective, the present review summarizes the evidence supporting the involvement of neurogenic inflammation and neuropeptides in the pathophysiology and pharmacology of migraine headache as well as its potential significance in better tailoring therapeutic interventions in migraine or other neurological disorders. In addition, we have briefly highlighted the pathophysiological role of neurogenic inflammation in various other neurological disorders.

Simvastatin Inhibits IL-5-Induced Chemotaxis and CCR3 Expression of HL-60-Derived and Human Primary Eosinophils

IL-5-induced chemotaxis of eosinophils is an important feature of allergic airway inflammatory diseases. Simvastatin, a lipid lowering agent, has been shown to exhibit anti-inflammatory and anti-allergic effects. Our aim was to investigate the effect of simvastatin on IL-5-induced eosinophil chemotaxis and its regulatory mechanisms. Eosinophils were derived by treating HL-60 clone 15 (HC15) cells with butyric acid (BA) in an alkaline condition or through direct isolation from human peripheral blood. The expressions of CC chemokine receptor 3 (CCR3) and interleukin (IL)-5 receptors (IL5Rα and β) were analyzed using RT/real-time PCR. The granular proteins were stained using fast green. Eotaxin-induced chemotaxis was measured using a transwell migration assay. CCR3 protein expression was revealed by immunocytochemistry. An animal model of allergic rhinitis was established by challenging Sprague-Dawley® rats repeatedly with ovalbumin. Butyric acid significantly increased the expression of IL5Rα and IL5Rβ, CCR3 and granular proteins in HC15 cells, indicating the maturation of eosinophils (BA-E cells). IL-5 further enhanced the CCR3 expression at both the mRNA and protein levels and the eotaxin-induced chemotaxis of BA-E cells. Simvastatin inhibited the effects of IL-5 on BA-E cells, but not in the presence of mevalonate. Similar results were also exhibited in human primary eosinophils. In vivo animal studies further confirmed that oral simvastatin could significantly suppress the infiltration of eosinophils into turbinate tissues of allergic rats. Therefore, simvastatin was demonstrated to inhibit IL-5-induced CCR3 expression and chemotaxis of eosinophils mediated via the mevalonate pathway. We confirmed that simvastatin also reduced eosinophilic infiltration in allergic rhinitis.

Could simvastatin be considered as a potential therapy for chronic lung diseases? A debate on the pros and cons

INTRODUCTION

Simvastatin (SV) is a drug from the statin class, currently used orally as an anti-cholesterolemic drug. It inhibits the 3-hydroxy-3-methyl-glutaryl-Coenzyme A (HMG-CoA) reductase to reduce cholesterol synthesis. Recently, it has been found that SV also has several other protective pharmacological actions unrelated to its anti-cholesterol effects that might be beneficial in the treatment of chronic airway diseases.

AREAS COVERED

This review summarizes the evidence relating to SV as a potential anti-inflammatory, anti-oxidant and muco-inhibitory agent, administered both orally and via pulmonary inhalation, and discusses its pro and cons. Evidence could potentially be used to support the delivery of SV as inhaled formulation for the treatment of chronic respiratory diseases.

EXPERT OPINION

The use of SV as anti-inflammatory, anti-oxidant and muco-inhibitory agent for drug delivery to the lung is promising. Inhaled SV formulations could allow the delivery profile to be customized and optimized to take advantage of the rapid onset of action, low systemic side effect and improved physico-chemical stability. This treatment could potentially to be used clinically for the localized treatment of lung diseases where inflammation and oxidative stress production is present.

Biomarkers of in vivo fluorescence imaging in allergic airway inflammation

Airway inflammation is a central component of the manifestation of asthma but is relatively inaccessible to study. Current imaging techniques such as X-ray CT, MRI, and PET, have advanced noninvasive research on pulmonary diseases. However, these techniques mainly facilitate the anatomical or structural assessment of the diseased lung and/or typically use radioactive agents. In vivo fluorescence imaging is a novel method for noninvasive, real-time, and specific monitoring of lung airway inflammation, which is particularly important to gain a further understanding asthma. Compared to conventional techniques, fluorescent imaging has the advantages of rapid feedback, as well as high sensitivity and resolution. Recently, there has been an increase in the identification of biomarkers, including matrix metalloproteinases, cathepsins, selectins, folate receptor-beta, nanoparticles, as well as sialic acid-binding immunoglobulin-like lectin-F to assess the level of airway inflammation in asthma. Recent advances in our understanding of these biomarkers as molecular probes for in vivo imaging are discussed in this review.

Fluvastatin Suppresses Mast Cell and Basophil IgE Responses: Genotype-Dependent Effects

Mast cell (MC)- and basophil-associated inflammatory diseases are a considerable burden to society. A significant portion of patients have symptoms despite standard-of-care therapy. Statins, used to lower serum cholesterol, have immune-modulating activities. We tested the in vitro and in vivo effects of statins on IgE-mediated MC and basophil activation. Fluvastatin showed the most significant inhibitory effects of the six statins tested, suppressing IgE-induced cytokine secretion among mouse MCs and basophils. The effects of fluvastatin were reversed by mevalonic acid or geranylgeranyl pyrophosphatase, and mimicked by geranylgeranyl transferase inhibition. Fluvastatin selectively suppressed key FcεRI signaling pathways, including Akt and ERK. Although MCs and basophils from the C57BL/6J mouse strain were responsive to fluvastatin, those from 129/SvImJ mice were completely resistant. Resistance correlated with fluvastatin-induced upregulation of the statin target HMG-CoA reductase. Human MC cultures from eight donors showed a wide range of fluvastatin responsiveness. These data demonstrate that fluvastatin is a potent suppressor of IgE-mediated MC activation, acting at least partly via blockade of geranyl lipid production downstream of HMG-CoA reductase. Importantly, consideration of statin use for treating MC-associated disease needs to incorporate genetic background effects, which can yield drug resistance.

Early-life antibiotic use is associated with wheezing among children with high atopic risk: a prospective European study

BACKGROUND

Little is known about the relationship between antibiotic use and asthma in the children with a higher risk of allergic sensitization. We examine the association between the use of specific therapeutic antibiotics in the first year of life and development of wheezing by 36 months among children with a higher risk of allergic sensitization.

METHODS

A multi-center prospective cohort study was conducted among children at high risk for allergic sensitization. A validated questionnaire was used to prospectively collect information on antibiotic use and potential risk factors for wheezing from parents or guardians of 606 children from three European countries at 6, 12, 24 and 36 months of age. Multivariate linear and logistic regression models were used to adjust for potential confounders and effect modifiers and to estimate the association of antibiotic use with the development of early childhood wheezing.

RESULTS

Of the antibiotics assessed, only macrolide use in the first year of life was associated with increasing risk for wheezing by 36 months, after adjusting for gender, socioeconomic status, breast feeding >6 months, tobacco smoke exposure, family history of asthma, and respiratory infection (RR = 1.09; 95% CI 1.05-1.13). To avoid a bias by indication, we analyzed children with and without respiratory infection separately. Similar associations were observed for macrolides use in children who had no respiratory infection.

CONCLUSIONS

In European children with a familial risk for allergic sensitization, we found a positive association between macrolide use in the first year of life and wheezing until 36 months old which was independent of the effect of respiratory infection.

Regulation of Adaptive Immunity in Health and Disease by Cholesterol Metabolism

Four decades ago, it was observed that stimulation of T cells induces rapid changes in cellular cholesterol that are required before proliferation can commence. Investigators returning to this phenomenon have finally revealed its molecular underpinnings. Cholesterol trafficking and its dysregulation are now also recognized to strongly influence dendritic cell function, T cell polarization, and antibody responses. In this review, the state of the literature is reviewed on how cholesterol and its trafficking regulate the cells of the adaptive immune response and in vivo disease phenotypes of dysregulated adaptive immunity, including allergy, asthma, and autoimmune disease. Emerging evidence supporting a potential role for statins and other lipid-targeted therapies in the treatment of these diseases is presented. Just as vascular biologists have embraced immunity in the pathogenesis and treatment of atherosclerosis, so should basic and clinical immunologists in allergy, pulmonology, and other disciplines seek to encompass a basic understanding of lipid science.

Biological Effects of Simvastatin Formulated as pMDI on Pulmonary Epithelial Cells

PURPOSE

The aim of this study is to evaluate the biological effects of Calu-3 epithelial cells in response to the delivery of simvastatin (SV) via solution pressurized metered dose inhaler (pMDI).

METHODS

SV pMDI was aerosolised onto Calu-3 air-interface epithelial cells using a modified glass twin stage impinger. The transport of SV across Calu-3 cells, mucus production, inflammatory cytokines production i.e., interleukin (IL) 6, 8 and tumour necrosis factor alpha (TNF- α) and oxidative stress from Calu-3 cells following treatment with SV pMDI was investigated and compared to untreated cells.

RESULTS

It was found that SV had the ability to penetrate into the respiratory epithelium and convert into its active SV hydroxy acid (SVA) metabolite. Furthermore, the amount of mucus produced was significantly reduced when SV was deposited on Calu-3 compared to untreated cells. Additionally, SV delivered by pMDI reduces production of IL-6, 8 and TNF-α from Calu-3 following stimulation with lipopolysaccharide (LPS). SV also showed equivalent antioxidant property to vitamin E.

CONCLUSIONS

Treatment with SV solution pMDI formulation on Calu-3 cells reduces mucus production, inflammatory cytokines and oxidative stress. This formulation could potentially be used clinically as muco-inhibitory and anti-inflammatory therapy for treatment of chronic lung diseases.

Oxidative stress and inflammation are differentially affected by atorvastatin, pravastatin, rosuvastatin, and simvastatin on lungs from mice exposed to cigarette smoke

Our aim was to investigate the effects of four different statins on acute lung inflammation induced by cigarette smoke (CS). C57BL/6 male mice were divided into a control group (sham-smoked) and mice exposed to CS from 12 cigarettes/day for 5 days. Mice exposed to CS were grouped and treated with vehicle (i.p.), atorvastatin (10 mg/kg), pravastatin (10 mg/kg), rosuvastatin (5 mg/kg), or simvastatin (20 mg/kg). Treatment with statins differentially improved the pulmonary response when compared to the CS group. Atorvastatin and pravastatin demonstrated slightly effects on inflammation and oxidative stress. Rosuvastatin demonstrated the best anti-inflammatory effect, whereas simvastatin demonstrated the best antioxidant response.

Intratracheal instillation of pravastatin for the treatment of murine allergic asthma: a lung-targeted approach to deliver statins

Systemic treatment with statins mitigates allergic airway inflammation, T_H2 cytokine production, epithelial mucus production, and airway hyperreactivity (AHR) in murine models of asthma. We hypothesized that pravastatin delivered intratracheally would be quantifiable in lung tissues using mass spectrometry, achieve high drug concentrations in the lung with minimal systemic absorption, and mitigate airway inflammation and structural changes induced by ovalbumin. Male BALB/c mice were sensitized to ovalbumin (OVA) over 4 weeks, then exposed to 1% OVA aerosol or filtered air (FA) over 2 weeks. Mice received intratracheal instillations of pravastatin before and after each OVA exposure (30 mg/kg). Ultra performance liquid chromatography – mass spectrometry was used to quantify plasma, lung, and bronchoalveolar lavage fluid (BALF) pravastatin concentration. Pravastatin was quantifiable in mouse plasma, lung tissue, and BALF (BALF > lung > plasma for OVA and FA groups). At these concentrations pravastatin inhibited airway goblet cell hyperplasia/metaplasia, and reduced BALF levels of cytokines TNFα and KC, but did not reduce BALF total leukocyte or eosinophil cell counts. While pravastatin did not mitigate AHR, it did inhibit airway hypersensitivity (AHS). In this proof-of-principle study, using novel mass spectrometry methods we show that pravastatin is quantifiable in tissues, achieves high levels in mouse lungs with minimal systemic absorption, and mitigates some pathological features of allergic asthma. Inhaled pravastatin may be beneficial for the treatment of asthma by having direct airway effects independent of a potent anti-inflammatory effect. Statins with greater lipophilicity may achieve better anti-inflammatory effects warranting further research.

Attenuation of airway inflammation by simvastatin and the implications for asthma treatment: is the jury still out?

Although some studies have explained the immunomodulatory effects of statins, the exact mechanisms and the therapeutic significance of these molecules remain to be elucidated. This study not only evaluated the therapeutic potential and inhibitory mechanism of simvastatin in an ovalbumin (OVA)-specific asthma model in mice but also sought to clarify the future directions indicated by previous studies through a thorough review of the literature. BALB/c mice were sensitized to OVA and then administered three OVA challenges. On each challenge day, 40 mg kg⁻¹ simvastatin was injected before the challenge. The airway responsiveness, inflammatory cell composition, and cytokine levels in bronchoalveolar lavage (BAL) fluid were assessed after the final challenge, and the T cell composition and adhesion molecule expression in lung homogenates were determined. The administration of simvastatin decreased the airway responsiveness, the number of airway inflammatory cells, and the interleukin (IL)-4, IL-5 and IL-13 concentrations in BAL fluid compared with vehicle-treated mice (P<0.05). Histologically, the number of inflammatory cells and mucus-containing goblet cells in lung tissues also decreased in the simvastatin-treated mice. Flow cytometry showed that simvastatin treatment significantly reduced the percentage of pulmonary CD4⁺ cells and the CD4⁺/CD8⁺ T-cell ratio (P<0.05). Simvastatin treatment also decreased the expression of the vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 proteins, as measured in homogenized lung tissues (P<0.05) and human epithelial cells. The reduction in the T cell influx as a result of the decreased expression of cell adhesion molecules is one of the mechanisms by which simvastatin attenuates airway responsiveness and allergic inflammation. Rigorous review of the literature together with our findings suggested that simvastatin should be further developed as a potential therapeutic strategy for allergic asthma.

The effects of nodakenin on airway inflammation, hyper-responsiveness and remodeling in a murine model of allergic asthma

CONTEXT

Nodakenin is a major coumarin glucoside in the root of Peucedanum decursivum Maxim, a commonly used traditional Chinese medicine for the treatment of asthma and chronic bronchitis for thousands of years.

OBJECTIVE

In this work, the anti-asthma potential of nodakenin was studied by investigation of its effect to suppress airway inflammation, hyper-responsiveness and remodeling in a murine model of chronic asthma.

MATERIALS AND METHODS

BALB/c mice sensitized to ovalbumin (OVA) were challenged with aerosolized OVA for 8 weeks, orally administered with nodakenin at doses of 5, 10 and 20 mg/kg before each OVA challenge.

RESULTS

Compared with the model group, nodakenin treatment markedly inhibited airway inflammation, hyper-responsiveness and remodeling, showing improvement in subepithelial fibrosis, smooth muscle hypertrophy, and goblet cell hyperplasia, and decreased levels of interleukin (IL)-4, IL-5, IL-13 and matrix metalloproteinase-2/-9 in bronchoalveolar lavage fluid, and the level of OVA-specific IgE in serum. In addition, the NF-κB DNA-binding activity in lung tissues was also reduced by nodakenin treatment.

CONCLUSIONS

These data indicated that nodakenin might mitigate the development of chronic experimental allergic asthma.

Newer glucocorticosteroids and corticosteroid resistance reversal in asthma

Inflammation is the hallmark of asthma. Glucocorticosteroids inhibit this inflammation and are the mainstay of therapy in asthma, however, they suffer from their own drawbacks. They possess high potency but their continued use has a negative influence on health. Hence, quest for a steroid with good potency but without the undesirable effects is ongoing. Besides, steroid resistance is a problem in a substantial proportion of severe asthmatics. Deeper insight into the molecular mechanism of this refractoriness has led to the successful trial of certain drugs to overcome this problem. This review attempts to discuss some of the patents related to improved glucocorticoids and those agents that have the potential to restore steroid sensitivity in severe asthmatics.

The effect of atorvastatin on lung histopathology in a murine model of chronic asthma

INTRODUCTION

Atorvastatin is a statin group medicine that reduces the level of serum cholesterol; thus it is used to treat hypercholesterolaemia. Independent of the cholesterol-lowering property of statins they also have anti-inflammatory and immunomodulating effects. This study aimed to investigate the effect of atorvastatin on histological changes in the lungs in a murine model of chronic asthma.

MATERIALS AND METHODS

Twenty-eight BALB/c mice in Group I, II, III and IV were divided into four groups. All the mice except the control group (Group I) were sensitised with ovalbumin. Intraperitoneal injection with saline, atorvastatin (10mg/kg), dexametazon (1mg/kg) was administered to Group II, Group III, and Group IV respectively for five consecutive days. Mice were sacrificed 24h after the last drug administration. All the histological properties of lung tissue samples from all groups were evaluated with light and electron microscopy. In addition, IL-4 and IL-5 levels of the lung tissue were measured.

RESULTS

When Group II and Group III (atorvastatin) were compared, thicknesses of basement membrane and subepithelial smooth muscle layer, height of epithelium, number of mast and goblet cells were significantly lower in Group III. In comparing Group III (atorvastatin) and Group IV (dexamethasone), all the improvements in histological parameters were similar. In addition, the IL-4 and IL-5 levels of the lung tissue were significantly lower in atorvastatin group (Group III) compared to placebo-treated group.

CONCLUSION

Atorvastatin had a beneficial effect on histological changes in a chronic murine model of asthma.

Statins in the treatment of asthma

PURPOSE

Current evidence on statin agents as potential alternatives or adjuncts to corticosteroid therapy for asthma is reviewed.

SUMMARY

Research showing antiinflammatory and antioxidant effects of statins in animal models suggested that the cholesterol-lowering drugs might be useful in mitigating the adverse effects of long-term corticosteroid therapy in patients with asthma, but studies in humans have yielded mixed results. Two small placebo-controlled clinical trials indicated that statins were not effective in combating asthmatic inflammatory processes, and trials of statins as adjunctive therapy have indicated minimal steroid-sparing benefits. In two studies involving a total of more than 1000 current and former smokers with asthma, statin use correlated with reduced acute asthma exacerbations and a slower decline of lung function in some patients. A large population-based study (n = 3965) found that statin therapy was associated with a significantly reduced risk of hospitalization for asthma after an average follow-up period of about 4.5 years; a smaller U.S. retrospective cohort study indicated a significantly lower 1-year rate of asthma-related emergency room visits among patients receiving statins relative to those not using statins (9.08% versus 4.18%). Much of the research on statins and asthma has not controlled for confounding influences such as patient comorbidities and concomitant medication use.

CONCLUSION

Clinical trials have shown that statin therapy is not superior to and does not enhance the beneficial effects of inhaled corticosteroids for the treatment of asthma. Some evidence suggests that statins may help preserve lung function in cigarette smokers with obstructive pulmonary disease and reduce hospitalizations in asthmatic smokers and nonsmokers.

Targeting the mevalonate cascade as a new therapeutic approach in heart disease, cancer and pulmonary disease

The cholesterol biosynthesis pathway, also known as the mevalonate (MVA) pathway, is an essential cellular pathway that is involved in diverse cell functions. The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR) is the rate-limiting step in cholesterol biosynthesis and catalyzes the conversion of HMG-CoA to MVA. Given its role in cholesterol and isoprenoid biosynthesis, the regulation of HMGCR has been intensely investigated. Because all cells require a steady supply of MVA, both the sterol (i.e. cholesterol) and non-sterol (i.e. isoprenoid) products of MVA metabolism exert coordinated feedback regulation on HMGCR through different mechanisms. The proper functioning of HMGCR as the proximal enzyme in the MVA pathway is essential under both normal physiologic conditions and in many diseases given its role in cell cycle pathways and cell proliferation, cholesterol biosynthesis and metabolism, cell cytoskeletal dynamics and stability, cell membrane structure and fluidity, mitochondrial function, proliferation, and cell fate. The blockbuster statin drugs ('statins') directly bind to and inhibit HMGCR, and their use for the past thirty years has revolutionized the treatment of hypercholesterolemia and cardiovascular diseases, in particular coronary heart disease. Initially thought to exert their effects through cholesterol reduction, recent evidence indicates that statins also have pleiotropic immunomodulatory properties independent of cholesterol lowering. In this review we will focus on the therapeutic applications and mechanisms involved in the MVA cascade including Rho GTPase and Rho kinase (ROCK) signaling, statin inhibition of HMGCR, geranylgeranyltransferase (GGTase) inhibition, and farnesyltransferase (FTase) inhibition in cardiovascular disease, pulmonary diseases (e.g. asthma and chronic obstructive pulmonary disease (COPD)), and cancer.

Detection and monitoring of localized matrix metalloproteinase upregulation in a murine model of asthma

Extracellular proteases including matrix metalloproteinases (MMPs) are speculated to play a significant role in chronic lung diseases, such as asthma. Although increased protease expression has been correlated with lung pathogenesis, the relationship between localized enzyme activity and disease progression remains poorly understood. We report the application of MMP-2/9 activatable cell-penetrating peptides (ACPPs) and their ratiometric analogs (RACPPs) for in vivo measurement of protease activity and distribution in the lungs of mice that were challenged with the allergen ovalbumin. MMP-2/9 activity was increased greater than twofold in whole, dissected lungs from acutely challenged mice compared with control mice (P=1.8×10(-4)). This upregulation of MMP-2/9 activity was localized around inflamed airways with 1.6-fold higher protease-dependent ACPP uptake surrounding diseased airways compared with adjacent, pathologically normal lung parenchyma (P=0.03). MMP-2/9 activity detected by ACPP cleavage colocalized with gelatinase activity measured with in situ dye-quenched gelatin. For comparison, neutrophil elastase activity and thrombin activity, detected with elastase- and thrombin-cleavable RACPPs, respectively, were not significantly elevated in acutely allergen-challenged mouse lungs. The results demonstrate that ACPPs, like the MMP-2/9-activated and related ACPPs, allow for real-time detection of protease activity in a murine asthma model, which should improve our understanding of protease activation in asthma disease progression and help elucidate new therapy targets or act as a mechanism for therapeutic drug delivery.

CD1d expressed in mast cell surface enhances IgE production in B cells by up-regulating CD40L expression and mediator release in allergic asthma in mice

Mast cells play important roles via FcεRI-mediated activation in allergic asthma. A nonpolymorphic MHC I-like molecule CD1d, which is mainly expressed in APCs, presents glycolipid Ag to iTCR on iNKT cells and modulates allergic responses. This study aimed to investigate the role of CD1d on IgE production and mast cell activation related to allergic asthma. Bone marrow-derived mast cells (BMMCs) from C57BL/6 Wild type (WT) or KO (CD1d(-/-)) mice were activated with Ag/Ab (refer to WT-act-BMMCs and KO-act-BMMCs, respectively) or α-Galactosylceramide (WT-αGal-BMMCs, KO-αGal-BMMCs) in the presence of iNKT cells. WT, KO or BMMC-transferred KO mice were sensitized and/or challenged by OVA or α-Gal to induce asthma. KO-act-BMMCs reduced intracellular Ca(2+) levels, expression of signaling molecules (Ras, Rac1/2, PLA2, COX-2, NF-κB/AP-1), mediator release (histamines, leukotrienes and cytokines/chemokines), and total IgE levels versus the corresponding WT-BMMCs. KO mice reduced total and OVA-specific serum IgE levels, number of mast cells, recruiting molecules (CCR2/CCL2, VCAM-1, PECAM-1), expression of tryptase, c-kit, CD40L and cytokine mRNA, co-localization of c-kit and CD1d or iNKT cells in BAL cells or lung tissues, and PCA responses, compared with the corresponding WT mice. BMMC-transferred KO-both mice showed the restoration of all allergic responses versus KO-both mice (Ag/Ab reaction plus α-Gal). KO-αGal-BMMCs or KO-αGal mice did not show any responses. Our data suggest that CD1d-expressed mast cells may function as APC cells for iNKT cells and exacerbate airway inflammation and remodeling through up-regulating IgE production via B cell Ig class switching and mediator release in mast cells of OVA-challenged mice.

Is serum cholesterol a risk factor for asthma?

BACKGROUND

Proinflammatory role of serum cholesterol in asthma has been recently explored with contradicting results. Clarity on the link between serum cholesterol and asthma may lead to new evolutions in planning management strategies. The objective of our study was to examine the relationship between the serum cholesterol, asthma and its characteristics.

MATERIALS AND METHODS

A total of 40 asthmatics and 40 normal subjects were examined cross-sectionally and their serum fasting cholesterol and serum high sensitivity C reactive protein (hsCRP) levels were measured along with other baseline investigations. All subjects were non-smokers.

RESULTS

Serum total cholesterol (mean ± SD) among asthmatics was 176.45 ± 30.77 mgs/dL as compared to 163.33 ± 26.38 mgs/dL among normal subjects (P < 0.05). This higher serum cholesterol level was found to be associated with asthma independent of age, gender, body mass index (BMI), socio-economic status and serum hsCRP levels. However, the association was only modest (adjusted odds ratio 1.033; 95% confidence interval [CI] 1.008-1.059). There was no association between the serum cholesterol and asthma characteristics such as duration of illness, intake of inhaled steroids and frequency of emergency department visits. Other risk factors identified were poor ventilation (adjusted odds ratio 9.27; 95%CI 1.83-46.99) and overcrowding (adjusted odds ratio 41.9; 95% CI 3.15-557.46) at home.

CONCLUSION

Our study found a modest but significant association between higher levels of serum cholesterol and asthma, which is independent of age, gender, BMI, socio-economic status and serum hsCRP. Future research is required in a larger population to substantiate above association and its clinical implications. Poor ventilation and overcrowding at home are risk factors for asthma possibly facilitating increased exposure to indoor allergens.

Serum low density lipoprotein subclasses in asthma

BACKGROUND

The levels of serum low-density lipoproteins (LDL) have been implicated in the inflammatory cascade in a murine model of asthma. Recent findings suggest that LDL may modulate the inflammatory state of the asthmatic airways in humans.

OBJECTIVE

We explored whether LDL subclasses are associated with the occurrence and severity of asthma.

METHODS

24 asthmatics (M/F: 11/13) and 24 healthy individuals, with normal BMI and absence of metabolic syndrome, matched for age and gender. Serum concentrations of LDL subclasses were distributed as seven bands (LDL-1 and -2 defined as large, least pro-inflammatory LDL, and LDL-3 to -7 defined as small, most pro-inflammatory LDL), using the LipoPrint(©) System (Quantimetrix Corporation, Redondo Beach, CA, USA).

RESULTS

LDL-1 was similar in the two groups (56 ± 16% vs. 53 ± 11, p = NS), while LDL-2 was significantly lower in asthmatics as compared to controls (35 ± 8% vs. 43 ± 10%, p = 0.0074). LDL-3 levels were two-fold higher in the asthmatics, but the difference did not reach the statistical significance (8 ± 7.3% vs. 4 ± 3%, p = NS). Smaller subclasses LDL-4 to LDL-7 were undetectable in controls. In asthmatics, LDL-1 was positively associated with VC% predicted (r = +0.572, p = 0.0035) and FEV1% predicted (r = +0.492, p = 0.0146). LDL-3 was inversely correlated with both VC% predicted (r = -0.535, p = 0.0071) and FEV1% predicted (r = -0.465, p = 0.0222).

CONCLUSIONS

The findings of this pilot study suggest a role of LDL in asthma, and advocate for larger studies to confirm the association between asthma and dyslipidemia.

Alendronate attenuates eosinophilic airway inflammation associated with suppression of Th2 cytokines, Th17 cytokines, and eotaxin-2

Bisphosphonates (BPs) have been widely used to treat osteoporosis. They act by inhibiting farnesyl diphosphate synthase in the mevalonate pathway. This resembles the action of statins, whose immune-modulating effect has recently been highlighted. In contrast, the effect of BPs on immune responses has not been elucidated well. In this study, we examined the effect of alendronate (ALN), a nitrogen-containing BP, on allergic airway inflammation in a mouse model. BALB/c mice were sensitized twice with OVA and challenged three times with nebulized OVA to induce eosinophilic airway inflammation. ALN was administered by an intragastric tube before each inhalation. ALN strongly suppressed airway eosinophilia and Th2, as well as Th17 cytokine production in the lung. ALN also attenuated eotaxin-2 production in the lung. Immunohistochemistry demonstrated that the major cell source of eotaxin-2 was peribronchial/perivascular macrophages, and flow cytometrical studies confirmed that ALN decreased eotaxin-2 expression in these macrophages. Furthermore, ALN attenuated eotaxin-2 production from mouse pleural macrophages and human monocyte/macrophage-like THP-1 cells in vitro. These results suggest that ALN suppressed Ag-induced airway responses in the mouse model. The suppression of eotaxin-2 production from macrophages appears to be one of ALN's immunomodulatory effects, whereas the mechanism by which ALN suppressed Th2 and Th17 responses could not be fully elucidated in this study. Although a clinical study should be conducted, ALN could be a novel therapeutic option for asthma.

Eosinophil apoptosis and clearance in asthma

Asthma is an increasingly common respiratory condition characterized by reversible airway obstruction, bronchial hyper-responsiveness and airway inflammation with a clear unmet need for more effective therapy. Eosinophilic asthma is a phenotype of the condition that features increased blood or sputum eosinophils whose numbers correlate with disease severity. Several lines of evidence are now emerging, which implicate increased persistence of eosinophils in the lungs of patients with asthma as a consequence of inhibition of and defects in the apoptotic process, together with impaired apoptotic cell removal mechanisms. This article will update our knowledge of the mechanisms controlling eosinophil apoptosis and clearance, together with evidence implicating defects in apoptosis and pro-inflammatory cell removal in asthma. Recent developments in novel therapies for asthma that target eosinophil apoptotic and/or clearance pathways will also be discussed.