Asthma biomarkers in sputum

Microbial contributions to bronchial asthma occurrence in children: A metagenomic study

Bronchial asthma, a common chronic respiratory disease in children, is traditionally regarded as a noninfectious disease. Current hypotheses, however, argue that asthma can be caused by microbial infection. We, therefore, hypothesize that a variety of microbes are more commonly found in the sputum of children with asthma, and these microbes may contribute to the occurrence and development of asthma. The present study proposes to use metagenomic approach to explore microbial diversity and to identify the microbial community characteristics of sputum from children with asthma. We found that microbial communities in the sputum of children differed significantly between asthmatics and controls. Kruskal-Wallis testing showed that 16 phyla, 104 genera, and 159 species were significantly downregulated, whereas two phyla including Platyhelminthes phylum and Chordata phylum, two genera including Spirometra genus and Homo sapiens, and the Spirometra erinaceieuropaei species were significantly upregulated in asthma patients compared with controls (P < 0.05). Among them, H. sapiens and S. erinaceieuropaei exhibited 2.3- and 2.0-fold overabundance in asthmatics vs controls, respectively. Meanwhile, metastats assay demonstrated that 31 phyla, 400 genera, and 813 species were significantly downregulated, whereas two phyla, 10 genera, and 16 species were significantly upregulated in asthma patients compared with controls (P < 0.05). Among them, Tetrahymena thermophila and Candidatus Zinderia insecticola exhibited 4.7-fold overabundance in asthmatics vs controls. Our study establishes a link between microbial infection and the mechanisms leading to asthma development, which will be useful for developing novel diagnostic biomarkers and aiding in the prevention and control of asthma.

Health care resource utilization and characteristics of patients with eosinophilic asthma in secondary health care in Finland

Background: Eosinophilic airway inflammation is common in asthma patients and appears to be associated with severe exacerbations and loss of asthma control. Objective: To describe the resource utilization and clinical characteristics of patients with eosinophilic asthma. Design: Asthma patients ≥18 years with ≥1 blood eosinophil count in secondary care (South West Finland) during 2003‒2013 were included. Clinical characteristics (age, lung function, body mass index, and comorbidities) and asthma-related resource utilization (hospital admissions, outpatient visits, and emergency room [ER] visits) were retrieved. Resource utilization rates were compared for patients with blood eosinophil ≤ or >300 cells/μL, using adjusted negative binomial regression models. Results: Overall, 4,357 eligible patients were identified (mean age 60 years, females 68%), of which 1,927 (44%) had >300 eosinophil cells/μL blood. Patients with ≤300 and >300 eosinophil counts, exhibited similar clinical characteristics, including advanced age, poor lung function, and overweight. Comorbidities such as pneumonia, sinusitis, and nasal polyps, were more frequent among those with >300 eosinophil cells/μL blood compared with patients with lower counts. Eosinophil counts >300 cells/μL were associated with greater hospital admissions (rate ratio [RR] [95% confidence interval CI]: 1.13 [1.02;1.24]) and outpatient visits (RR [95% CI]: 1.11 [1.03;1.20]) compared with patients with lower eosinophil counts. Rates of ER visits were similar between the patient groups (RR [95% CI]: 0.99 [0.87;1.12]). Conclusions: Hospital admissions and outpatient visits occurred more often for patients with eosinophil counts >300 cells/µL, than for patients with lower eosinophil counts. Routine blood eosinophil screening might be useful to identify patients with an eosinophilic phenotype eligible for more targeted treatments.

Tuberculosis State Is Associated with Expression of Toll-Like Receptor 2 in Sputum Macrophages

Mycobacterium tuberculosis is an intracellular pathogen that parasitizes the host macrophage. While approximately two billion people are infected worldwide, only 5 to 10% become diseased with pulmonary tuberculosis, at least in the absence of comorbidities. Tuberculosis control requires development of noninvasive methods probing the host immune status to help distinguish latent infection from active tuberculosis. With such methods, high-risk individuals could be targeted for treatment before disease manifestation. Previous investigations have been based on examination of peripheral blood cells or, more rarely, lung macrophages obtained with invasive procedures, such as bronchoalveolar lavages. Here we show that differences exist in the expression of a surface protein (Toll-like receptor 2) between macrophages recovered from the sputum of individuals in different diagnostic groups: i.e., infection free, latent tuberculosis infection, and active pulmonary tuberculosis. Thus, phenotypic analysis of local macrophages obtained with noninvasive procedures can help distinguish among tuberculosis infection stages.

During tuberculosis, macrophages are critical for both pathogen survival and host immune activation. Since expression of particular cell surface markers reflects cell function, we used flow cytometry to measure the abundance of surface markers associated with polarity, lipid uptake, or pattern recognition on macrophages found in induced sputum. Nine macrophage surface markers were examined from three groups of donors: infection-free, latent tuberculosis infection, and active pulmonary tuberculosis. Using a trend test, we found that expression of Toll-like receptor 2 was greater from absence of infection to latent infection and from latent infection to active tuberculosis. The results point to the possibility that innate immune cell phenotypes be used to distinguish among tuberculosis infection stages. Moreover, this study shows that readily accessible sputum macrophages have potential for tuberculosis diagnosis and prognosis.

IMPORTANCEMycobacterium tuberculosis is an intracellular pathogen that parasitizes the host macrophage. While approximately two billion people are infected worldwide, only 5 to 10% become diseased with pulmonary tuberculosis, at least in the absence of comorbidities. Tuberculosis control requires development of noninvasive methods probing the host immune status to help distinguish latent infection from active tuberculosis. With such methods, high-risk individuals could be targeted for treatment before disease manifestation. Previous investigations have been based on examination of peripheral blood cells or, more rarely, lung macrophages obtained with invasive procedures, such as bronchoalveolar lavages. Here we show that differences exist in the expression of a surface protein (Toll-like receptor 2) between macrophages recovered from the sputum of individuals in different diagnostic groups: i.e., infection free, latent tuberculosis infection, and active pulmonary tuberculosis. Thus, phenotypic analysis of local macrophages obtained with noninvasive procedures can help distinguish among tuberculosis infection stages.

The chemokines secretion and the oxidative stress are targets of low-level laser therapy in allergic lung inflammation

Recent studies show that low-level laser therapy (LLLT) has an important anti-inflammatory action in acute lung inflammation. The present work explored if laser therapy is able to antagonize eosinophils and allergic inflammation induced by oxidative stress in Balb/c mice. Forty-eight hours after challenge, the leukocyte counting, ROS and nitrite/nitrate level, RANTES, CCL3, CCL8 as well as eotaxins were measured in the bronchoalveolar lavage fluid (BALF) of laser-treated mice or not. Into the lung, some chemokines receptors, the iNOS activity and mRNA expression, and the activities of superoxide dismutase (SOD), catalase, gluthatione, NADPH oxidase activities and thiobarbituric acid reactive species (T-Bars) were measured. Laser-treated allergic mice presented reduction of both the ICAM-1 and eosinophil in the lungs. RANTES, CCL8, CCL3 and eotaxins were reduced in BALF of laser-treated allergic mice. In allergic mice lung LLLT decreased the CCR1 and CCR3 and restored the oxidative stress balance as well. Laser decreased the lipidic peroxidation in allergic mice lung as much as increased SOD, GPx and GR. It shows that LLLT on allergic lung inflammation involves leukocyte-attractant chemokines and endogenous antioxidant. Based on results, LLLT may ultimately become a non- invasive option in allergic lung disease treatment. The top figure illustrates the laser decreasing the eosinophils migration into BALF and the bottom figure shows the laser upregulating the expression of heme-oxygenase (anti-oxidant enzyme) in lung tissue anti-oxidant.

Burden of asthma with elevated blood eosinophil levels

Background

Asthma is a common chronic condition with an economic burden of almost $56 billion annually in the US. Biologic markers like blood eosinophils, that help predict the risk of exacerbation could help guide more optimal treatment plans and reduce cost. The purpose of this study was to determine whether healthcare resource use and expenditures vary by eosinophil level among patients with asthma.

Methods

Patients with a diagnosis of asthma defined by ICD-9-CM code 493.xx between January 2004 and July 2011 were extracted from EMRClaims + database (eMAX Health, White Plains NY). Patients were classified as mild, moderate, or severe by medication use following diagnosis, based on recommendations of National Institutes of Health Expert Panel Report 3. Patients were classified as those with elevated eosinophils (≥400 cells/μL) and normal eosinophil level (<400 cells/μL). Patients were followed for resource use, defined as hospitalizations, ER visits and outpatient visit and associated costs were calculated to assess whether an economic difference exists between eosinophil groups. Non-parametric tests were used to compare resource use and associated cost between elevated and normal eosinophil groups. Multivariate modeling was performed to assess the contribution of eosinophil level on the likelihood of study outcomes among patients with severe asthma.

Results

Among the 2,164 patients meeting eligibility criteria, 1,144 had severity designations. Of these, 179(16 %) of patients had severe asthma of which 20 % (n = 35) had elevated eosinophils. Seventeen percent of patients with elevated eosinophils were admitted to the hospital during the follow-up period, significantly greater than patients with normal eosinophil levels (12 %; p = 0.011). Overall, compared to patients with normal eosinophil levels (n = 1734), patients with elevated eosinophil levels (n = 430) had significantly greater mean annual hospital admissions (0.51 vs. 0.21/year, p = 0.006) and hospital costs (2,536 vs. $1,091, p = 0.011). Logistic regressions showed that elevated eosinophil level was associated with 5.14 times increased odds of all cause admissions (95 % CI:1.76–14.99, p = 0.003) and 4.07 times increased odds of asthma related admissions (95 % CI: 1.26–13.12, p = 0.019).

Conclusion

Eosinophil elevation was associated with greater healthcare resource use in patients with asthma.

Biologic targeted therapy in allergic asthma

OBJECTIVE

To review the structure, function, clinical utility, and safety of current biologic targeted therapies being used for the treatment of asthma.

DATA SOURCES

Medical literature obtained from PubMed and OVID searches from June to November 2013.

STUDY SELECTIONS

Studies were selected based on article impact, relevance, and clinical significance. Particular emphasis was placed on articles discussing therapies targeted at IgE, interleukin (IL)-4, IL-4 receptor, IL-5, IL-13, tumor necrosis factor-α, CRTh2, and toll-like receptors 7 and 9.

RESULTS

Since the approval of omalizumab in 2003, the development of biologic asthma therapies has grown at a remarkable pace. With approximately 30 drugs currently in clinical trials and dozens more in development, the future of asthma biologic therapies is promising. Despite several well-publicized setbacks, researchers remain focused on elucidating the complex pathophysiology of asthma. The hope is that asthma biologic therapies will eventually be tailored to an individual's asthma phenotype. With more than 300 million people worldwide affected by asthma and with roughly 5% to 10% of this population living with severe, uncontrolled asthma, the need for new biologic therapies is great.

CONCLUSION

The introduction of each new biologic therapy into clinical trials has been associated with great anticipation, but the outcome of these trials, in many cases, has led to disappointment. Given the lack of overwhelming positive responses, these results have emphasized that asthma is a complex clinical syndrome with multiple underlying genotypes and clinical phenotypes. It has become abundantly clear that it is very unlikely that there is one "magic bullet" to cure all patients with asthma.

The effect of rhinovirus on airway inflammation in a murine asthma model

PURPOSE

The aim of the present study was to investigate the differences in lower airway inflammatory immune responses, including cellular responses and responses in terms of inflammatory mediators in bronchoalveolar lavage fluid (BALF) and the airway, to rhinovirus (RV) infection on asthma exacerbation by comparing a control and a murine asthma model, with or without RV infection.

METHODS

BALB/c mice were intraperitoneally injected with a crude extract of Dermatophagoides farinae (Df) or phosphate buffered saline (PBS) and were subsequently intranasally treated with a crude extract of Df or PBS. Airway responsiveness and cell infiltration, differential cell counts in BALF, and cytokine and chemokine concentrations in BALF were measured 24 hours after intranasal RV1B infection.

RESULTS

RV infection increased the enhanced pause (Penh) in both the Df sensitized and challenged mice (Df mice) and PBS-treated mice (PBS mice) (P<0.05). Airway eosinophil infiltration increased in Df mice after RV infection (P<0.05). The levels of interleukin (IL) 13, tumor necrosis factor alpha, and regulated on activation, normal T cells expressed and secreted (RANTES) increased in response to RV infection in Df mice, but not in PBS mice (P<0.05). The level of IL-10 significantly decreased following RV infection in Df mice (P<0.05).

CONCLUSION

Our findings suggest that the augmented induction of proinflammatory cytokines, Th2 cytokines, and chemokines that mediate an eosinophil response and the decreased induction of regulatory cytokines after RV infection may be important manifestations leading to airway inflammation with eosinophil infiltration and changes in airway responsiveness in the asthma model.

Effect of formoterol on eosinophil trans-basement membrane migration induced by interleukin-8-stimulated neutrophils

BACKGROUND

Neutrophils are often increased in the airways of either chronic severe asthma or acute exacerbations. Neutrophils that have migrated in response to interleukin-8 (IL-8) may lead eosinophils to accumulate in the airways of patients with asthma and possibly aggravate the disease. In this study, we investigated whether formoterol modified the trans-basement membrane migration (TBM) of eosinophils stimulated with neutrophils and IL-8.

METHODS

Neutrophils and eosinophils were isolated from peripheral blood obtained from healthy donors. Eosinophil TBM was examined using a modified Boyden's chamber technique. Neutrophils were preincubated with or without formoterol (0.1 μM) at 37°C for 30 min. Eosinophils were added to the upper compartment of a chamber with a Matrigel-coated transwell insert. Medium containing preincubated neutrophils and IL-8 was added to the lower compartment of the chamber. After a 90-minute incubation, the eosinophils that had migrated into the lower chamber were calculated using eosinophil peroxidase assays.

RESULTS

A combination of neutrophils and IL-8 significantly induced the eosinophil TBM; formoterol alone had no effect. However, formoterol modestly but significantly attenuated the TBM of eosinophils stimulated with neutrophils and IL-8.

CONCLUSION

These results suggest that formoterol may act as a therapeutic agent on enhanced eosinophilic inflammation in acute exacerbation or persistent, severe asthma. The effect of formoterol likely involves the inhibition of neutrophil activation.