Evaluation of atorvastatin for the treatment of patients with asthma: a double-blind randomized clinical trial

Real-World Effectiveness of Statin Therapy in Adult Asthma

BACKGROUND

Blood lipids affect airway inflammation in asthma. Although several studies have suggested anti-inflammatory effects of statins on asthmatic airways, further studies are needed to clarify the long-term effectiveness of statins on asthma control and whether they are an effective treatment option.

OBJECTIVE

To evaluate the long-term effectiveness of statins in the chronic management of adult asthma in real-world practice.

METHODS

Electronic medical record data spanning 28 years, collected from the Ajou University Medical Center in Korea, were used to conduct a retrospective study. Clinical outcomes were compared between patients with asthma who had maintained statin use (the statin group) and those not taking statins, whose blood lipid tests were always normal (the non-statin group). We performed propensity score matching and calculated hazard ratios with 95% CIs using the Cox proportional hazards model. Severe asthma exacerbation was the primary outcome; asthma exacerbation, asthma-related hospitalization, and new-onset type 2 diabetes mellitus and hypertension were secondary outcomes.

RESULTS

After 1:1 propensity score matching, the statin and non-statin groups each included 545 adult patients with asthma. The risk of severe asthma exacerbations and asthma exacerbations was significantly lower in the statin group than in the non-statin group (hazard ratios [95% CI] = 0.57 [0.35-0.90] and 0.71 [0.52-0.96], respectively). There were no significant differences in the risk of asthma-related hospitalization or new-onset type 2 diabetes mellitus or hypertension between groups (0.76 [0.53-1.09], 2.33 [0.94-6.59], and 1.71 [0.95-3.17], respectively).

CONCLUSION

Statin use is associated with a lower risk of asthma exacerbation, with better clinical outcomes in adult asthma.

Sterols and immune mechanisms in asthma

The field of sterol and oxysterol biology in lung disease has recently gained attention, revealing a unique need for sterol uptake and metabolism in the lung. The presence of cholesterol transport, biosynthesis, and sterol/oxysterol-mediated signaling in immune cells suggests a role in immune regulation. In support of this idea, statin drugs that inhibit the cholesterol biosynthesis rate-limiting step enzyme, hydroxymethyl glutaryl coenzyme A reductase, show immunomodulatory activity in several models of inflammation. Studies in human asthma reveal contradicting results, whereas promising retrospective studies suggest benefits of statins in severe asthma. Here, we provide a timely review by discussing the role of sterols in immune responses in asthma, analytical tools to evaluate the role of sterols in disease, and potential mechanistic pathways and targets relevant to asthma. Our review reveals the importance of sterols in immune processes and highlights the need for further research to solve critical gaps in the field.

Sterols in asthma

While sterols regulate immune processes key to the pathogenesis of asthma, inhibition of sterols with statin drugs has shown conflicting results in human asthma. Here, a novel understanding of the impact of sterols on type 17 immune responses and asthma lead us to hypothesize that sterols and statins may be relevant to severe asthma endotypes with neutrophil infiltration.

Effect of atorvastatin on serum periostin and blood eosinophils in asthma - a placebo-controlled randomized clinical trial

Objective

To investigate the effect of atorvastatin on serum periostin level and blood eosinophil count in patients with asthma.

Methods

Patients diagnosed with asthma were enrolled and randomised into an intervention or placebo group, to receive 40 mg atorvastatin or similar placebo, daily, for 8 weeks. Spirometry was performed at baseline, and at the end of weeks 4 and 8; patients also provided blood samples and completed an asthma control test (ACT) at baseline and at the end of week 8. Primary study outcomes were blood eosinophil count and serum periostin levels.

Results

Eighty patients completed the study (40 per group). Mean ACT scores were similar between the intervention and placebo groups at baseline (17.95 ± 3.75 versus 17.98 ± 3.77, respectively), and improved in the intervention group (19.88 ± 3.28), but remained unchanged in the placebo group (18.6 ± 3.26) during the treatment period. No statistically significant differences in spirometric changes, blood eosinophil count or serum periostin levels were observed between the groups during the treatment period.

Conclusion

Spirometric parameters and inflammatory markers did not change significantly in response to atorvastatin treatment, and did not differ between the placebo and intervention groups.

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.

The effect of statins for asthma. A systematic review and meta-analysis

OBJECTIVE

To assess the effects of statins on asthma by systematically reviewing and conducting a meta-analysis on all clinical studies, including randomized controlled trials (RCTs) and observational studies, that examined the effects of statins on asthma.

METHODS

PubMed, EMBASE databases, and Cochrane reviews were searched to identify RCTs and observational studies, conducted through June 16, 2020, that assessed the effect of statins as a treatment for asthma. A meta-analysis was conducted using the following main outcomes: asthma control test (ACT), asthma control questionnaire (ACQ), pre- and post-bronchodilator forced expiratory volume in one second (FEV1), peak flow (PEF), and asthma exacerbation (asthma-related emergency department (ED) visits and hospitalization).

RESULTS

Our search revealed 11 RCTs and 8 observational studies that met the inclusion criteria. A meta-analysis demonstrated that statin treatment significantly improved ACT scores (mean difference: 1.61, P < 0.001) and ACQ scores (mean difference: -0.38, P < 0.001) compared to a placebo. Furthermore, statin treatment significantly reduced asthma-related ED visits (hazard ratio [HR], 95% confidence interval [CI], 0.83 [0.75-0.92], P < 0.001, number needed to treat [NNT], 5.9). However, statin treatment did not improve pulmonary function (FEV1 and PEF).

CONCLUSION

Our results suggest that statins have the potential to improve asthma control and reduce asthma exacerbation without any improvement in pulmonary function.

Supplemental data for this article can be accessed at publisher's website.

Effect of atorvastatin on testosterone levels

BACKGROUND

Statins are one of the most prescribed classes of drugs worldwide. Atorvastatin, the most prescribed statin, is currently used to treat conditions such as hypercholesterolaemia and dyslipidaemia. By reducing the level of cholesterol, which is the precursor of the steroidogenesis pathway, atorvastatin may cause a reduction in levels of testosterone and other androgens. Testosterone and other androgens play important roles in biological functions. A potential reduction in androgen levels, caused by atorvastatin might cause negative effects in most settings. In contrast, in the setting of polycystic ovary syndrome (PCOS), reducing excessive levels of androgens with atorvastatin could be beneficial.

OBJECTIVES

Primary objective To quantify the magnitude of the effect of atorvastatin on total testosterone in both males and females, compared to placebo or no treatment. Secondary objectives To quantify the magnitude of the effects of atorvastatin on free testosterone, sex hormone binding globin (SHBG), androstenedione, dehydroepiandrosterone sulphate (DHEAS) concentrations, free androgen index (FAI), and withdrawal due to adverse effects (WDAEs) in both males and females, compared to placebo or no treatment.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials (RCTs) up to 9 November 2020: the Cochrane Hypertension Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; Embase; ;two international trials registries, and the websites of the US Food and Drug Administration, the European Patent Office and the Pfizer pharmaceutical corporation. These searches had no language restrictions. We also contacted authors of relevant articles regarding further published and unpublished work.

SELECTION CRITERIA

RCTs of daily atorvastatin for at least three weeks, compared with placebo or no treatment, and assessing change in testosterone levels in males or females.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the citations, extracted the data and assessed the risk of bias of the included studies. We used the mean difference (MD) with associated 95% confidence intervals (CI) to report the effect size of continuous outcomes,and the risk ratio (RR) to report effect sizes of the sole dichotomous outcome (WDAEs). We used a fixed-effect meta-analytic model to combine effect estimates across studies, and risk ratio to report effect size of the dichotomous outcomes. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included six RCTs involving 265 participants who completed the study and their data was reported. Participants in two of the studies were male with normal lipid profile or mild dyslipidaemia (N = 140); the mean age of participants was 68 years. Participants in four of the studies were female with PCOS (N = 125); the mean age of participants was 32 years. We found no significant difference in testosterone levels in males between atorvastatin and placebo, MD -0.20 nmol/L (95% CI -0.77 to 0.37). In females, atorvastatin may reduce total testosterone by -0.27 nmol/L (95% CI -0.50 to -0.04), FAI by -2.59 nmol/L (95% CI -3.62 to -1.57), androstenedione by -1.37 nmol/L (95% CI -2.26 to -0.49), and DHEAS by -0.63 μmol/l (95% CI -1.12 to -0.15). Furthermore, compared to placebo, atorvastatin increased SHBG concentrations in females by 3.11 nmol/L (95% CI 0.23 to 5.99). We identified no studies in healthy females (i.e. females with normal testosterone levels) or children (under age 18). Importantly, no study reported on free testosterone levels.

AUTHORS' CONCLUSIONS

We found no significant difference between atorvastatin and placebo on the levels of total testosterone in males. In females with PCOS, atorvastatin lowered the total testosterone, FAI, androstenedione, and DHEAS. The certainty of evidence ranged from low to very low for both comparisons. More RCTs studying the effect of atorvastatin on testosterone are needed.

The potential of Atorvastatin for chronic lung diseases therapy

Atorvastatin (ATO) is of the statin class and is used as an orally administered lipid-lowering drug. ATO is a reversible synthetic competitive inhibitor of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase thus leading to a reduction in cholesterol synthesis. It has recently been demonstrated that ATO has different pharmacological actions, which are unrelated to its lipid-lowering effects and has the ability to treat chronic airway diseases. This paper reviews the potential of ATO as an anti-inflammatory, antioxidant, and anti-proliferative agent after oral or inhaled administration. This paper discusses the advantages and disadvantages of using ATO under conditions associated with those found in the airways. This treatment could potentially be used to support the formulating of ATO as an inhaler for the treatment of chronic respiratory diseases.

Statins for asthma

BACKGROUND

Asthma is a common chronic respiratory disease. People with asthma have inflammation of their airways that causes recurrent episodes of wheezing, breathlessness and chest tightness, with or without a cough. Statins possess multiple therapeutic effects, including lowering lipid levels in the blood. Statins are reported to have a potential role as an adjunct treatment in asthma. However, comprehensive evidence of the benefits and harms of using statins is required to facilitate decision making.

OBJECTIVES

To assess the benefits and harms of statins as an adjunct therapy for asthma in adults and children.

SEARCH METHODS

We searched for studies in the Cochrane Airways Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid SP and Embase Ovid SP, from their inception dates We handsearched the proceedings of major respiratory conferences. We also searched clinical trials registries for completed, ongoing and unpublished studies, and scanned the reference lists of included studies and relevant reviews to identify additional studies. The search is current to 7 February 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with a parallel-group design that assessed statins for at least 12 weeks' duration. We considered all participants with a clinical diagnosis of asthma to be eligible, regardless of age, sex, disease severity and previous or current treatment. We planned to include studies reported as full text, those published as abstract only, and unpublished data.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected the studies, extracted outcome data and intervention characteristics from included studies, and assessed risk of bias according to standard Cochrane methodological procedures. We resolved any disagreement through discussion.

MAIN RESULTS

We found only one trial involving a total of 60 people living with asthma. The trial compared the effect of atorvastatin with a placebo (dummy treatment containing lactose) in treating people with chronic asthma. The trial did not report data for the primary outcomes or adverse events. There was uncertainty about the relative effect on forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) in the atorvastatin group compared with the placebo group. The study did not report serious adverse effects for the interventions. The included study had internal discrepancies in its reported data.

AUTHORS' CONCLUSIONS

The evidence was of very low certainty, so we are unable to draw conclusions about the effectiveness and safety of statins to treat asthma. High-quality RCTs are needed to assess the effect of statins on people with asthma. Well-designed multicentre trials with larger samples and longer duration of treatment are required, which assess outcomes such as adverse events, hospital utilisation and costs, to provide better quality evidence. Future studies that include subgroups of obese people with asthma are also required.

Asthma and metabolic syndrome: a comprehensive systematic review and meta-analysis of observational studies

Introduction: This study aimed to perform a meta-analysis on the prevalence of metabolic syndrome (MetS) among patients with asthma and to measure the association asthma has with MetS.

Methods: The Web of Science, Medline, Scopus, Embase and Google Scholar were searched using the "Asthma", "Metabolic Syndrome", "Dysmetabolic Syndrome", "Cardiovascular Syndrome", "Insulin Resistance Syndrome", "Prevalence", "Odds Ratio", "Cross-Sectional Studies", and "Case-Control Studies" keywords. All observational studies reporting the prevalence of MetS among people with and without asthma were included in the study. In the presence of heterogeneity, random-effects models were used to pool the prevalence and odds ratios (OR), as measures of association in cross-sectional and case-control/ cohort studies, respectively.

Results: The prevalence of MetS among patients with asthma (8 studies) and the OR comparing the prevalence of MetS among patients with and without asthma (5 studies) were pooled separately. The pooled prevalence of MetS among patients with asthma was found to be 25% (95% confidence interval (CI): 13%–38%). In contrast, the overall pooled OR for MetS in patients with asthma, compared to healthy controls, was 1.34 (95% CI: 0.91–1.76), which was not statistically significant.

Conclusion: The prevalence of MetS was relatively high in patients with asthma. Furthermore, the odds of MetS was higher in patients with asthma, compared to healthy controls, although this difference was not statistically significant. More original studies among different populations are needed in order to more accurately examine the association between asthma and MetS, as well as the relationship asthma has with the individual components of MetS.

Repurposing of statins via inhalation to treat lung inflammatory conditions

Despite many therapeutic advancements over the past decade, the continued rise in chronic inflammatory lung diseases incidence has driven the need to identify and develop new therapeutic strategies, with superior efficacy to treat these diseases. Statins are one class of drug that could potentially be repurposed as an alternative treatment for chronic lung diseases. They are currently used to treat hypercholesterolemia by inhibiting the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, that catalyses the rate limiting step in the mevalonate biosynthesis pathway, a key intermediate in cholesterol metabolism. Recent research has identified statins to have other protective pleiotropic properties including anti-inflammatory, anti-oxidant, muco-inhibitory effects that may be beneficial for the treatment of chronic inflammatory lung diseases. However, clinical studies have yielded conflicting results. This review will summarise some of the current evidences for statins pleiotropic effects that could be applied for the treatment of chronic inflammatory lung diseases, their mechanisms of actions, and the potential to repurpose statins as an inhaled therapy, including a detailed discussion on their different physical-chemical properties and how these characteristics could ultimately affect treatment efficacies. The repurposing of statins from conventional anti-cholesterol oral therapy to inhaled anti-inflammatory formulation is promising, as it provides direct delivery to the airways, reduced risk of side effects, increased bioavailability and tailored physical-chemical properties for enhanced efficacy.

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.

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.

Drug repurposing to treat asthma and allergic disorders: Progress and prospects

Allergy and atopic asthma have continued to become more prevalent in modern society despite the advent of new treatments, representing a major global health problem. Common medications such as antihistamines and steroids can have undesirable long-term side-effects and lack efficacy in some resistant patients. Biologic medications are increasingly given to treatment-resistant patients, but they can represent high costs, complex dosing and management, and are not widely available around the world. The field needs new, cheap, and convenient treatment options in order to bring better symptom relief to patients. Beyond continued research and development of new drugs, a focus on drug repurposing could alleviate this problem by repositioning effective and safe small-molecule drugs from other fields of medicine and applying them toward the treatment for asthma and allergy. Herein, preclinical models, case reports, and clinical trials of drug repurposing efficacy in allergic disease are reviewed. Novel drugs are also proposed for repositioning based on their mechanism of action to treat asthma and allergy. Overall, drug repurposing could become increasingly important as a way of advancing allergy and atopic asthma therapy, filling a need in treatment of patients today.

Statins in the treatment of COPD and asthma-where do we stand?

Asthma and chronic obstructive pulmonary disease (COPD) are the two most prevalent obstructive lung diseases that account for tremendous morbidity and mortality throughout the world. These diseases have strong inflammatory components, with multiple prior studies showing elevated levels of various inflammatory markers and cells in those with COPD and asthma. Therefore, efforts to target inflammation in management of these diseases are of great interest. Statins, which define a class of drugs that are HMG-CoA inhibitors, are used to decrease cholesterol levels and have also been described to have many pleotropic effects that include anti-inflammatory and anti-oxidative properties. These properties have led to multiple studies looking at the potential use of statins in decreasing inflammation in many diseases, including COPD and asthma. This review aims to address the current evidence behind the potential use of statins in the treatment of asthma and COPD.

Statins in Asthma: Potential Beneficial Effects and Limitations

Asthma's sustenance as a global pandemic, across centuries, can be attributed to the lack of an understanding of its workings and the inability of the existing treatment modalities to provide a long lasting cure without major adverse effects. The discovery of statins boosted by a better comprehension of the pathophysiology of asthma in the past few decades has opened up a potentially alternative line of treatment that promises to be a big boon for the asthmatics globally. However, the initial excellent results from the preclinical and animal studies have not borne the results in clinical trials that the scientific world was hoping for. In light of this, this review analyzes the ways by which statins could benefit in asthma via their pleiotropic anti-inflammatory properties and explain some of the queries raised in the previous studies and provide recommendations for future studies in this field.

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.

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.

Asthma and metabolic syndrome: Current knowledge and future perspectives

Asthma and obesity are epidemiologically linked; however, similar relationships are also observed with other markers of the metabolic syndrome, such as insulin resistance and dyslipidemia, which cannot be accounted for by increased body mass alone. Obesity appears to be a predisposing factor for the asthma onset, both in adults and in children. In addition, obesity could make asthma more difficult to control and to treat. Although obesity may predispose to increased Th2 inflammation or tendency to atopy, other mechanisms need to be considered, such as those mediated by hyperglycaemia, hyperinsulinemia and dyslipidemia in the context of metabolic syndrome. The mechanisms underlying the association between asthma and metabolic syndrome are yet to be determined. In the past, these two conditions were believed to occur in the same individual without any pathogenetic link. However, the improvement in asthma symptoms following weight reduction indicates a causal relationship. The interplay between these two diseases is probably due to a bidirectional interaction. The purpose of this review is to describe the current knowledge about the possible link between metabolic syndrome and asthma, and explore potential application for future studies and strategic approaches.

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.

Statins and asthma: where we stand, and the next critical steps in research

Asthma remains a formidable public health problem with ever increasing annual costs and prevalence. There are 300 million people with asthma worldwide. Per the Centers for Disease Control and Prevention, there are over 25 million Americans with asthma (both children and adults), i.e. one in 12 people have asthma, and this is increasing annually. Asthma results in approximately half a million hospitalizations and two million emergency department (ED) visits per year. In 2007 alone, 185 children and 3262 adults died from asthma, i.e. nine to ten patients die a day from asthma. This resulted in an annual cost of $56 billion in medical costs, lost work/school days, and early deaths. Therefore, we need novel and innovative therapies for asthma. In this Editorial, I review results from a study by Tse et al. evaluating the therapeutic potential of statins, within the context of our current state of knowledge. I review observational studies and clinical trials, highlight some potential pitfalls in clinical trial design, and discuss important questions for future research.

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.

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.

Statin use and asthma control in patients with severe asthma

OBJECTIVES

We hypothesised that severe asthmatics taking a statin drug, in addition to inhaled corticosteroids/long-acting β-agonist inhaler therapy, would have better asthma symptom control and improved lung function compared to their controls.

STUDY DESIGN

A retrospective, cross-sectional study of 165 patients with severe asthma seen from 2001-2008. Hierarchical linear and logistic regression models were used for modelling fitting.

SETTING

University of California, Davis Medical Center (Sacramento, California, USA). Academic, single-centre, severe asthma subspecialty clinic.

PARTICIPANTS

612 screened, 223 eligible and 165 adult patients were included in the final study (N=165; 31 statin users and 134 non-users).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary endpoint was asthma control as measured by the Asthma Control Test (ACT). The secondary endpoints included lung function, symptoms and the need for corticosteroid burst and peripheral eosinophil count.

RESULTS

At baseline, statin users compared to non-users were older, had lower lung function (FEV1% predicted, FEV1, forced vital capacity and FEF25-75%) and had a higher prevalence of comorbid conditions. Statin use was associated with more aspirin and ipratropium inhaler use than in non-users. Patients in both groups were obese (body mass index ≥ 30). Statin users had better asthma symptom control compared to non-users (higher adjusted mean ACT score by 2.2±0.94 points, p<0.02). Median statin use was for 1 year. There were no statistically significant differences in lung function, corticosteroid or rescue bronchodilator use or peripheral eosinophilia between the two groups.

CONCLUSIONS

In our severe asthma referral population, statin users already taking inhaled controller therapy achieved better asthma control compared to non-users. The implications of this study is that patients with severe asthma could potentially benefit from added statin treatment. Because our study population was on average obese, the obese severe asthmatic may be a viable asthma subphenotype for further studies. Prospective randomised clinical trials evaluating the safety and efficacy of statins in severe asthma are warranted.

Newer treatments in the management of pediatric asthma

Asthma control remains a significant challenge in the pediatric age range in which ongoing loss of lung function in children with persistent asthma has been reported, despite the use of regular preventer therapy. This has important implications for observed mortality and morbidity during adulthood. Over the past decade, there has been an emergence of other treatment adjuncts, such as anti-Immunoglobulin E (IgE)-directed therapy, low dose theophylline, and the use of macrolide antibiotics, yet their exact role in asthma management remains unclear, despite omalizumab now being incorporated into several international asthma guidelines. As with many aspects of pediatric care, this is driven by a lack of appropriately designed pediatric trials. Extrapolation of data reported in adult studies may be appropriate for adolescent asthma, but is not for younger age groups, in which important pathophysiological differences exist. Novel drugs under development offer potential for benefit in the future, but to date existing data are in most cases limited to adults. Pediatric asthma also offers unique potential to prevent or modify the underlying pathophysiology. Although attempts to do so have been unsuccessful to date, advances may yet come from this approach, as our understanding about the interaction between genetics, environmental factors, and viral illness improve. This review provides an overview of the newer treatment options available for management of pediatric asthma and discusses the merits of other novel therapies in development, as we search to optimize management and improve future outcomes.

Statins as potential therapeutic drug for asthma?

Background

Statins are lipid-lowering agents that also exhibit pleiotropic effects in decreasing oxidative stress and inflammation. There have been several published studies reporting the use of statins in the treatment of asthma patients, but their results are not consistent. The aim of this study is to determine whether statins are beneficial for asthma administration, and explore the potential covariables that may affect their clinical effectiveness.

Methods

A systematic literature search was performed in PubMed, Embase and Cochrane Center Register of Controlled Trials from inception to September 2012. Randomized controlled trials (RCT), retrospective studies and controlled clinical trials which reported the use of statins in the treatment of asthma patients were eligible. Quality evaluation was conducted for RCT using Jadad criteria.

Results

A total of 18 articles were included. In our study, we found no conclusive evidence to demonstrate that statins could enhance the lung function in asthmatics, although, they may reduce airway inflammation. Additionally, the results were not consistent across studies with respect to symptoms, quality of life, maintenance medication, asthma hospitalization/emergency department (ED) visits.

Conclusions

Statins may reduce airway inflammation in asthmatics, without having a significant effect on lung function. Further large sample and multicenter clinical trials are needed to confirm this and to see if there are more responsive phenotypes of asthma.