Fluvastatin and lovastatin inhibit granulocyte macrophage-colony stimulating factor-stimulated human eosinophil adhesion to inter-cellular adhesion molecule-1 under flow conditions

Therapeutic effect of statins on airway remodeling during asthma

INTRODUCTION

Asthma is a chronic inflammatory disease of the airways, which is usually characterized by remodeling, hyperresponsiveness and episodic obstruction of the airways. The underlying chronic airway inflammation leads to pathological restructuring of both the large and small airways. Since the effects of current asthma medications on airway remodeling have been met with contradictions, many therapeutic agents have been redirected from their primary use for the treatment of asthma. Such treatments, which could target several signaling molecules implicated in the inflammatory and airway remodeling processes of asthma, would be an ideal choice.

AREAS COVERED

Statins are effective serum cholesterol-lowering agents that were found to have potential anti-inflammatory and anti-remodeling properties. Literature search was done for the past 10 years to include research and review articles in the field of statins and asthma complications. In this review, we discuss the role of statins in airway tissue remodeling and their potential therapeutic modalities in asthma.

EXPERT OPINION

With improved understanding of the role of statins in airway remodeling and inflammation, statins represent a potential therapeutic option for various asthma phenotypes. Further research is warranted to optimize statins for asthma therapy through inhalation as a possible route of administration.

Molecular Biology of Eosinophils: Introduction

The eosinophil is an enigmatic cell with a continuing ability to fascinate. A considerable history of research endeavor on eosinophil biology stretches from the present time back to the nineteenth century. Perhaps one of the most fascinating aspects of the eosinophil is how accumulating knowledge has changed the perception of its function from passive bystander, modulator of inflammation, to potent effector cell loaded with histotoxic substances through to more recent recognition that it can act as both a positive and negative regulator of complex events in both innate and adaptive immunity. This book consists of chapters written by experts in the field of eosinophil biology that provide comprehensive clearly written protocols for techniques designed to underpin research into the function of the eosinophil in health and disease.

Fluvastatin Induces Apoptosis in Primary and Transformed Mast Cells

Statin drugs are widely employed in the clinic to reduce serum cholesterol. Because of their hydroxymethylglutaryl coenzyme A reductase antagonism, statins also reduce isoprenyl lipids necessary for the membrane anchorage and signaling of small G-proteins in the Ras superfamily. We previously found that statins suppress immunoglobulin E (IgE)-mediated mast cell activation, suggesting these drugs might be useful in treating allergic disease. Although IgE-induced function is critical to allergic inflammation, mast cell proliferation and survival also impact atopic disease and mast cell neoplasia. In this study, we describe fluvastatin-mediated apoptosis in primary and transformed mast cells. An IC₅₀ was achieved between 0.8 and 3.5 μM in both cell types, concentrations similar to the reported fluvastatin serum C_max value. Apoptosis was correlated with reduced stem cell factor (SCF)-mediated signal transduction, mitochondrial dysfunction, and caspase activation. Complementing these data, we found that p53 deficiency or Bcl-2 overexpression reduced fluvastatin-induced apoptosis. We also noted evidence of cytoprotective autophagy in primary mast cells treated with fluvastatin. Finally, we found that intraperitoneal fluvastatin treatment reduced peritoneal mast cell numbers in vivo These findings offer insight into the mechanisms of mast cell survival and support the possible utility of statins in mast cell-associated allergic and neoplastic diseases. SIGNIFICANCE STATEMENT: Fluvastatin, a statin drug used to lower cholesterol, induces apoptosis in primary and transformed mast cells by antagonizing protein isoprenylation, effectively inhibiting stem cell factor (SCF)-induced survival signals. This drug may be an effective means of suppressing mast cell survival.

Effective antigen presentation to helper T cells by human eosinophils

Although eosinophils are inflammatory cells, there is increasing attention on their immunomodulatory roles. For example, murine eosinophils can present antigen to CD4⁺ T helper (Th) cells, but it remains unclear whether human eosinophils also have this ability. This study determined whether human eosinophils present a range of antigens, including allergens, to activate Th cells, and characterized their expression of MHC class II and co-stimulatory molecules required for effective presentation. Human peripheral blood eosinophils purified from non-allergic donors were pulsed with the antigens house dust mite extract (HDM), Timothy Grass extract (TG) or Mycobacterium tuberculosis purified protein derivative (PPD), before co-culture with autologous CD4⁺ Th cells. Proliferative and cytokine responses were measured, with eosinophil expression of HLA-DR/DP/DQ and the co-stimulatory molecules CD40, CD80 and CD86 determined by flow cytometry. Eosinophils pulsed with HDM, TG or PPD drove Th cell proliferation, with the response strength dependent on antigen concentration. The cytokine responses varied with donor and antigen, and were not biased towards any particular Th subset, often including combinations of pro- and anti-inflammatory cytokines. Eosinophils up-regulated surface expression of HLA-DR/DP/DQ, CD80, CD86 and CD40 in culture, increases that were sustained over 5 days when incubated with antigens, including HDM, or the major allergens it contains, Der p I or Der p II. Human eosinophils can, therefore, act as effective antigen-presenting cells to stimulate varied Th cell responses against a panel of antigens including HDM, TG or PPD, an ability that may help to determine the development of allergic disease.

Connectivity mapping (ssCMap) to predict A20-inducing drugs and their antiinflammatory action in cystic fibrosis

Cystic fibrosis (CF) lung disease is characterized by chronic and exaggerated inflammation in the airways. Despite recent developments to therapeutically overcome the underlying functional defect in the cystic fibrosis transmembrane conductance regulator, there is still an unmet need to also normalize the inflammatory response. The prolonged and heightened inflammatory response in CF is, in part, mediated by a lack of intrinsic down-regulation of the proinflammatory NF-κB pathway. We have previously identified reduced expression of the NF-κB down-regulator A20 in CF as a key target to normalize the inflammatory response. Here, we have used publicly available gene array expression data together with a statistically significant connections' map (sscMap) to successfully predict drugs already licensed for the use in humans to induce A20 mRNA and protein expression and thereby reduce inflammation. The effect of the predicted drugs on A20 and NF-κB(p65) expression (mRNA) as well as proinflammatory cytokine release (IL-8) in the presence and absence of bacterial LPS was shown in bronchial epithelial cells lines (16HBE14o-, CFBE41o-) and in primary nasal epithelial cells from patients with CF (Phe508del homozygous) and non-CF controls. Additionally, the specificity of the drug action on A20 was confirmed using cell lines with tnfαip3 (A20) knockdown (siRNA). We also show that the A20-inducing effect of ikarugamycin and quercetin is lower in CF-derived airway epithelial cells than in non-CF cells.

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.

Allergic Inflammation Is Associated With Coronary Instability and a Worse Clinical Outcome After Acute Myocardial Infarction

BACKGROUND

The role of allergic inflammation in acute coronary syndromes (ACS) has not been clearly defined to date. Aim of this study was to assess eosinophil and basophil activation in ACS and the prognostic role of eosinophil cationic protein in ST-segment-elevation myocardial infarction.

METHODS AND RESULTS

In a cross-sectional study, we prospectively enrolled 51 patients undergoing percutaneous coronary intervention (60.8% patients with ACS and 39.2% with stable angina). Flow cytometry analysis assessed CD66b, CD69, and CD203c median fluorescence intensity expression. In a follow-up study, 181 patients presenting with ST-segment-elevation myocardial infarction, undergoing primary percutaneous coronary intervention, were prospectively enrolled with a follow-up of 24 months. Eosinophil activation (CD66b) was similar in patients with ACS and stable angina (6.61 [4.91-7.72] versus 6.62 [5.27-8.73], P=0.63), whereas eosinophil degranulation (CD69) and basophil activation (CD203c) were higher in ACS patients compared with stable angina patients (1.38 [1.16-1.52] versus 1.17 [1-1.31], P=0.01); 0.97 [0.89-1.11] versus 0.92 [0.87-0.95], P=0.03, respectively). Eosinophil cationic protein serum levels were significantly higher in ST-segment-elevation myocardial infarction patients with major adverse cardiac events as compared with those without (21.1 [10.37-25.65] versus 7.83 [3.37-12.8] μg/L, P=0.01) and in patients with thrombus score >3 compared with those with thrombus score ≤3 (15.0 [9.8-24.7] versus 5.2 [3.5-22.9] μg/L, P=0.006). Eosinophil cationic protein serum levels predicted major adverse cardiac events during follow-up (odds ratio =1.041, 95% confidence interval 1.012-1.071, P=0.005). C-reactive protein serum levels showed a borderline statistical significance (odds ratio =0.904, 95% confidence interval 0.806-1.014, P=0.085).

CONCLUSIONS

These findings are the first demonstration of in vivo eosinophil degranulation and basophil activation during ACS and of the prognostic role of eosinophil cationic protein in ST-segment-elevation myocardial infarction.

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.

Adhesion of eosinophils to endothelial cells or substrates under flow conditions

Recruitment of eosinophils into the lung tissue is a critical event in allergic inflammatory reactions. Extravasation of eosinophils from the bloodstream is a highly dynamic multistep process that involves capture, rolling, activation, firm adhesion, and transendothelial and subendothelial migration of the cells. It is assumed that the rate-limiting step in this cascade is the capture and firm adhesion of cells to the endothelium. As such it is most critical to study endothelial-leukocyte interaction using assays which are capable of mimicking physiological flow conditions. Previously, various parallel flow chamber setups had been used for studying leukocyte adhesion to endothelial cells. Here we describe a highly reproducible technique for investigating eosinophil adhesion to endothelial cell layer or adhesion molecule/extracellular matrix protein coating in biochips by using a semiautomated microfluidic platform and live-cell imaging. In detail, we show eosinophil adhesion to endothelial cells activated by tumour necrosis factor (TNF) alpha, and adhesion to fibronectin of eosinophils stimulated by prostaglandin (PG) D2.

Allergen screening bioassays: recent developments in lab-on-a-chip and lab-on-a-disc systems

Allergies occur when a person's immune system mounts an abnormal response with or without IgE to a normally harmless substance called an allergen. The standard skin-prick test introduces suspected allergens into the skin with lancets in order to trigger allergic reactions. This test is annoying and sometimes life threatening. New tools such as lab-on-a-chip and lab-on-a-disc, which rely on microfabrication, are designed for allergy testing. These systems provide benefits such as short analysis times, enhanced sensitivity, simplified procedures, minimal consumption of sample and reagents and low cost. This article gives a summary of these systems. In particular, a cell-based assay detecting both the IgE- and non-IgE-type triggers through the study of degranulation in a centrifugal microfluidic system is highlighted.

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.

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.

A systematic review of statin efficacy in asthma

BACKGROUND

Statins are known for their lipid-lowering effects and role in the treatment of atherosclerotic disease. They also have anti-inflammatory and immunomodulatory properties which could benefit asthma patients. We aimed to review the evidence on the efficacy and safety of statins in asthma-related outcomes.

METHODS

A systematic review of the literature on the effects of statins on asthma-related outcomes was performed following a search of the National Guideline Clearinghouse, Cochrane, Scopus, and Pubmed Medline databases in January 2012. Randomized controlled trials (RCTs) and observational studies (cohort/case-control design) assessing the effect of statins were included. The Grading of Recommendations Assessment Development and Evaluation (GRADE) system was used to rate the levels of evidence and grade of recommendation.

RESULTS

Twenty-four of the 379 articles retrieved electronically and one article identified by hand search were selected for full-text scrutiny by two independent reviewers. Eight studies were included: six RCTs and two observational studies. Statin use was not associated with consistent, statistical significant improvements in patient outcomes (asthma control, quality of life, steroid-sparing effects) or disease outcomes (lung function, airway responsiveness), and all the studies analyzed had low or very low quality of evidence. Inflammatory outcome improvements were observed in mild allergic asthma.

CONCLUSION

Statins do not seem to have any additional benefit in asthma control or steroid-sparing effect in asthma treatment. Considering the prevalence of both statin use and asthma, more, better designed studies are needed to determine whether a specific phenotype of asthma exists that could benefit from statin treatment.

Effect of oral administration with pravastatin and atorvastatin on airway hyperresponsiveness and allergic reactions in asthmatic mice

BACKGROUND

Asthma is characterized by airway hyperresponsiveness and remodeling. Pravastatin and atorvastatin are used clinically as cholesterol-lowering agents but also exhibit anti-inflammatory and immunomodulating properties.

OBJECTIVE

To investigate the therapeutic effect of oral statins on airway hyperresponsiveness and allergic reaction.

METHODS

BALB/c mice received intraperitoneal sensitization and aerosol inhalation with ovalbumin consequently. One week after ovalbumin aerosol challenge, pravastatin, atorvastatin, or phosphate-buffered saline were given by intragastric gavage daily for 2 weeks. Airway hyperresponsiveness, serum allergen specific antibody levels, cytokine production by splenocytes, and bronchoalveolar lavage fluid were examined.

RESULTS

Both pravastatin and atorvastatin effectively reduced airway hyperresponsiveness. Pravastatin effectively suppressed both T(H)1- and T(H)2-mediated antibody responses, reducing serum specific IgE, IgG, IgG1, and IgG2a levels. Pravastatin also effectively reduced interleukin (IL) 4, IL-5, and interferon γ production but significantly enhanced IL-10 levels in splenocytes and BALF. Similarly, atorvastatin effectively attenuated production of specific IgE, IgG1, and IgG2a antibodies. It also significantly attenuated IL-4, interferon γ, and increased IL-10 concentration in bronchoalveolar lavage fluid and splenocytes.

CONCLUSION

Oral administration of pravastatin or atorvastatin not only was able to inhibit T(H)1 inflammatory responses but also had therapeutic effects on airway hyperresponsiveness and T(H)2 allergic responses. These results seem to suggest that these drugs have potential as a nonimmunosuppressive therapy for asthma and allergic diseases.

Pathogenesis and classification of eosinophil disorders: a review of recent developments in the field

Eosinophils and their products play an essential role in the pathogenesis of various reactive and neoplastic disorders. Depending on the underlying disease, molecular defect and involved cytokines, hypereosinophilia may develop and may lead to organ damage. In other patients, persistent eosinophilia is accompanied by typical clinical findings, but the causative role and impact of eosinophilia remain uncertain. For patients with eosinophil-mediated organ pathology, early therapeutic intervention with agents reducing eosinophil counts can be effective in limiting or preventing irreversible organ damage. Therefore, it is important to approach eosinophil disorders and related syndromes early by using established criteria, to perform all appropriate staging investigations, and to search for molecular targets of therapy. In this article, we review current concepts in the pathogenesis and evolution of eosinophilia and eosinophil-related organ damage in neoplastic and non-neoplastic conditions. In addition, we discuss classifications of eosinophil disorders and related syndromes as well as diagnostic algorithms and standard treatment for various eosinophil-related disorders.

Simvastatin delivery via inhalation attenuates airway inflammation in a murine model of asthma

The dose-response of the pleiotropic effects of statins on airway inflammation has not yet been established and may differ from that of their cholesterol-lowering effects. High oral doses of statins may have adverse effects, and it may be possible to overcome the side effects and low clinical efficacy by administering statins via inhalation. In this study, we hypothesize that simvastatin is a potential anti-inflammatory drug with biological and pharmacokinetic properties suitable for delivery by the inhaled route. Mice were immunized with ovalbumin (OVA) and then challenged with aerosol OVA. Simvastatin was locally delivered by inhalation (i.h.) and intratracheal injection (i.t.) or systematically delivered by intraperitoneal injection (i.p.) and gavage (i.g.) during the OVA challenge. In a mouse model of asthma, i.h. simvastatin significantly and dose-dependently attenuated airway inflammation, remodeling and hyperresponsiveness in a RhoA-dependent pathway. Upon comparing the pharmacodynamics, i.h. simvastatin had a more potent effect than that of i.g. and i.p. simvastatin, and the i.h. or i.t. delivery routes led to a higher drug concentration in local lung tissue and a lower drug concentration in the plasma than that obtained by the i.g. These results suggest that simvastatin is a potential anti-inflammatory drug for airway inflammatory diseases with properties suitable for delivery by inhalation, which will probably reduce the side effects and increase clinical efficacy.

Treatment of allergic asthma: modulation of Th2 cells and their responses

Atopic asthma is a chronic inflammatory pulmonary disease characterised by recurrent episodes of wheezy, laboured breathing with an underlying Th2 cell-mediated inflammatory response in the airways. It is currently treated and, more or less, controlled depending on severity, with bronchodilators e.g. long-acting beta agonists and long-acting muscarinic antagonists or anti-inflammatory drugs such as corticosteroids (inhaled or oral), leukotriene modifiers, theophyline and anti-IgE therapy. Unfortunately, none of these treatments are curative and some asthmatic patients do not respond to intense anti-inflammatory therapies. Additionally, the use of long-term oral steroids has many undesired side effects. For this reason, novel and more effective drugs are needed. In this review, we focus on the CD4+ Th2 cells and their products as targets for the development of new drugs to add to the current armamentarium as adjuncts or as potential stand-alone treatments for allergic asthma. We argue that in early disease, the reduction or elimination of allergen-specific Th2 cells will reduce the consequences of repeated allergic inflammatory responses such as lung remodelling without causing generalised immunosuppression.

Implant-induced intraperitoneal inflammatory angiogenesis is attenuated by fluvastatin

1. Statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA) inhibitors, exert anti-inflammatory, anti-oxidant and anti-angiogenic effects. These effects are associated with downregulation of pro-inflammatory/pro-angiogenic molecules and upregulation of endothelial nitric oxide synthase (e-NOS) expression/nitric oxide (NO) production. 2. Using the murine sponge model to induce chronic intraperitoneal inflammatory response, we evaluated the inflammatory components, angiogenic and NO production of the fibrovascular tissue, and their modulation by fluvastatin. 3. Our results showed that fluvastatin (0.6 and 6 mg/kg per day) inhibited haemoglobin (Hb) content 4.9±0.4 (n=15; control) vs 2.2±0.2 (n=6; fluvastatin 0.6) and 1.8±0.2 (n=6; fluvastatin 6.0) and the number of vessels in the treated group when compared with the control group. The inflammatory component, as assessed by myeloperoxidase and N-acetyl-β-d-glucosaminidase activities and by the pro-inflammatory cytokines, tumour necrosis factor-α (TNF-α) and Monocyte chemotactic protein-1 (MCP-1)/CCL2/JE levels, was also decreased by the compound. In the treated group, inhibition of both enzyme activities was 54% and 57%, respectively. The levels of the cytokines (TNF-α and CCL2/JE) intra-implant were decreased relative to the control. In these implants, fluvastatin was also able to increase NO production, as detected with an NO-sensitive electrode. 4. The inhibitory function of fluvastatin on key components of intraperitoneal inflammatory angiogenesis shown in the present study is clearly associated with the modulatory effects of this statin on vascular endothelial growth factor, TNF-α and NO production.

Fluid dynamics analysis of a novel micropatterned cell bioreactor

Although flow-based bioreactor has been widely used to provide sufficient mass transportation and nutrient supply for cell proliferation, differentiation, and apoptosis, the underlying mechanism of cell responses to applied flow at single cell level remains unclear. This study has developed a novel bioreactor that combines flow bioreactor with microfabrication technique to isolate individual cells onto micropatterned substrate. A mechanical model has also been developed to quantify the flow field or the microenvironment around the single cell; flow dynamics has been analyzed on five geometrically different patterns of circle-, cube-, 1:2 ellipse-, 1:3 ellipse-, and rectangle-shaped "virtual cells." The results of this study have demonstrated that the flow field is highly pattern dependent, and all the hydrodynamic development length, cell spacing, and orientation of inlet velocity vector are crucial for maintaining a fully developed flow. This study has provided a theoretical basis for optimizing the design of micropatterned flow bioreactor and a novel approach to understand the cell mechanotransduction and cell-surface interaction at single cell level.

Controversial data on simvastatin in asthma: What about the rat model?

The effects of simvastatin on lung inflammation in asthma are controversial. Reduction of inflammation and hyperreactivity has been reported in studies using murine models of asthma. In contrast, a clinical study has not found beneficial effects in patients. The rat model of asthma has some distinct advantages and is still widely used in industrial studies. Therefore, the role of simvastatin was investigated in this rat model using intraperitoneal and intratracheal administration. With both simvastatin administration routes, the relative and absolute numbers of neutrophils, eosinophils, and lymphocytes were only partially reduced after increasing dosages (0.1, 1.0, and 10 mg per animal). The most obvious effect was on CD4 T cell numbers, which were reduced in most treatment groups. The results presented here suggest that treatment with simvastatin differs between species, and that it is too early for extrapolation of these data to humans.