Lipid and protein metabolism in asthma. Effects of diet and corticosteroid therapy

Naples prognostic score as a novel prognostic prediction indicator in adult asthma patients: A population-based study

Objective

This study was to evaluate the prognostic value of the Naples prognostic score (NPS) in adult patients with asthma.

Methods

Data on 44 601 participants from the 1999-2018 National Health and Nutrition Examination Survey (NHANES) were analyzed. The NPS was calculated based on serum albumin, total cholesterol, neutrophil-to-lymphocyte ratio (NLR), and lymphocyte-to-monocyte ratio (LMR), and participants were divided into 3 groups. Self-administered questionnaires were used to collect information on asthma, and mortality was identified using the National Death Index through December 31, 2019. Multiple logistic regressions were used to analyze the relationship between NPS and its components and the prevalence of asthma. Kaplan-Meier survival analysis, Cox proportional regressions, and the random survival forest (RSF) were used to assess the significance of NPS and its components in predicting all-cause and cause-specific (cardiovascular, cancer, and respiratory diseases) mortality in asthma patients.

Results

The mean age of the participants was 47.59 ± 0.18 years, and 48.47% were male. The prevalence of asthma was 13.11%. The participants were categorized into 3 groups: 8306 (18.6%) participants were in group 0 (NPS 0), 30 842 (69.2%) were in group 1 (NPS 1 or 2), and 5453 (11.2%) were in group 2 (NPS 3 or 4). Compared to the reference group, participants in group 2 had a higher prevalence of asthma (odds ratio [OR] = 1.40 [1.24-1.56]). Participants with asthma in group 2 had a significantly increased risk of all-cause mortality (hazard ratio [HR] = 2.42 [1.67-3.50]), cardiovascular mortality (HR = 2.68 [1.50-4.79]), cancer mortality (HR = 2.10 [1.00-4.45]), and respiratory disease mortality (HR = 3.00 [1.18-7.65]) compared to those with asthma in group 0. The RSF showed that NPS had the highest value in predicting all-cause mortality in adults with asthma, compared to its components.

Conclusions

The results of this study indicate that the NPS is a powerful prognostic indicator for outcomes in asthma patients.

Hidden Comorbidities in Asthma: A Perspective for a Personalized Approach

Bronchial asthma is the most frequent inflammatory non-communicable condition affecting the airways worldwide. It is commonly associated with concomitant conditions, which substantially contribute to its burden, whether they involve the lung or other districts. The present review aims at providing an overview of the recent acquisitions in terms of asthma concomitant systemic conditions, besides the commonly known respiratory comorbidities. The most recent research has highlighted a number of pathobiological interactions between asthma and other organs in the view of a shared immunological background underling different diseases. A bi-univocal relationship between asthma and common conditions, including cardiovascular, metabolic or neurodegenerative diseases, as well as rare disorders such as sickle cell disease, α1-Antitrypsin deficiency and immunologic conditions with hyper-eosinophilia, should be considered and explored, in terms of diagnostic work-up and long-term assessment of asthma patients. The relevance of that acquisition is of utmost importance in the management of asthma patients and paves the way to a new approach in the light of a personalized medicine perspective, besides targeted therapies.

The relationship between high-density lipoprotein cholesterol and overall sleep quality in the adult population with asthma

Previous basic studies have shown that high-density lipoprotein cholesterol (HDL-C) has anti-inflammatory effects that protect against asthma. Our study was aimed at examining the association between blood lipid levels and sleep quality in the adult population with asthma. We evaluated the blood lipid levels and sleep scores of 1013 adult participants in the Midlife in the United States (MIDUS) study to investigate the association of lipid levels with overall sleep quality using linear regression models in subjects with asthma and without asthma, respectively. In a total of 1013 participants (with asthma = 127 and without asthma = 886) included in our study, participants with asthma had poor sleep quality, compared with participants without asthma. Moreover, our smooth curves suggested that blood HDL-C and triglyceride levels, rather than total cholesterol and low-density lipoprotein cholesterol (LDL-C), were significantly associated with global sleep score. Multivariate correction models were used to further evaluate blood lipid profiles and the overall sleep quality. We observed that only blood HDL-C levels were still negatively and independently associated with global sleep score in participants with asthma (Sβ = - 0.224, 95% CI - 0.448, - 0.001, P = 0.049) but not in participants without asthma (Sβ = - 0.016, 95% CI - 0.087, 0.055, P = 0.656) in Model 3 after adjusting for age, gender, ever smoker, number of drinking years, exercise and body mass index (BMI). Obviously, asthma had a modification effect on the independent association (P interaction = 0.022). Our study suggested that elevated blood HDL-C levels are associated with a reduced risk for poor sleep quality in the adult population with asthma but not in those without asthma.

The Precision Interventions for Severe and/or Exacerbation-Prone (PrecISE) Asthma Network: An overview of Network organization, procedures, and interventions

Asthma is a heterogeneous disease, with multiple underlying inflammatory pathways and structural airway abnormalities that impact disease persistence and severity. Recent progress has been made in developing targeted asthma therapeutics, especially for subjects with eosinophilic asthma. However, there is an unmet need for new approaches to treat patients with severe and exacerbation-prone asthma, who contribute disproportionately to disease burden. Extensive deep phenotyping has revealed the heterogeneous nature of severe asthma and identified distinct disease subtypes. A current challenge in the field is to translate new and emerging knowledge about different pathobiologic mechanisms in asthma into patient-specific therapies, with the ultimate goal of modifying the natural history of disease. Here, we describe the Precision Interventions for Severe and/or Exacerbation-Prone Asthma (PrecISE) Network, a groundbreaking collaborative effort of asthma researchers and biostatisticians from around the United States. The PrecISE Network was designed to conduct phase II/proof-of-concept clinical trials of precision interventions in the population with severe asthma, and is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health. Using an innovative adaptive platform trial design, the PrecISE Network will evaluate up to 6 interventions simultaneously in biomarker-defined subgroups of subjects. We review the development and organizational structure of the PrecISE Network, and choice of interventions being studied. We hope that the PrecISE Network will enhance our understanding of asthma subtypes and accelerate the development of therapeutics for severe asthma.

High-Density Lipoprotein (HDL) in Allergy and Skin Diseases: Focus on Immunomodulating Functions

From an evolutionary perspective, lipoproteins are not only lipid transporters, but they also have important functions in many aspects of immunity. High-density lipoprotein (HDL) particles are the most abundant lipoproteins and the most heterogeneous in terms of their composition, structure, and biological functions. Despite strong evidence that HDL potently influences the activity of several immune cells, the role of HDL in allergies and skin diseases is poorly understood. Alterations in HDL-cholesterol levels have been observed in allergic asthma, allergic rhinitis, atopic dermatitis (eczema), psoriasis, urticaria, and angioedema. HDL-associated apolipoprotein (apo) A-I, apoA-IV, and apoC-III, and lyso-phosphatidylcholines potently suppress immune cell effector responses. Interestingly, recent studies provided evidence that allergies and skin diseases significantly affect HDL composition, metabolism, and function, which, in turn, could have a significant impact on disease progression, but may also affect the risk of cardiovascular disease and infections. Interestingly, not only a loss in function, but also, sometimes, a gain in function of certain HDL properties is observed. The objective of this review article is to summarize the newly identified changes in the metabolism, composition, and function of HDL in allergies and skin diseases. We aim to highlight the possible pathophysiological consequences with a focus on HDL-mediated immunomodulatory activities.

Clinical Phenotypes of Patients Hospitalized for an Asthma Exacerbation: Prognostic Implications

BACKGROUND

Hospitalization due to acute asthma exacerbation (AE) is a highly detrimental situation requiring critical management to prevent further deterioration, including mechanical ventilation, intensive care unit (ICU) admission, and death. However, patients hospitalized for AEs are highly heterogeneous and remain largely unexplored.

OBJECTIVE

To identify clinical and inflammatory phenotypes of AE requiring hospitalization associated with in-hospital outcomes.

METHODS

We performed a hierarchical cluster analysis of 825 consecutively recruited patients hospitalized for AEs. Logistic regressions were conducted to quantify the independent associations of the identified phenotypes with in-hospital outcomes. Decision tree analysis was developed to predict cluster assignment.

RESULTS

We identified 3 clusters of patients, which had significantly different characteristics associated with in-hospital adverse outcomes. Cluster 1 (n = 526, 63.8%) was a late-onset phenotype, cluster 2 (n = 97, 11.8%) was an early-onset phenotype, and cluster 3 (n = 202, 24.5%) was a phenotype with fewer eosinophils and more comorbidities. Clusters 2 and 3 had an elevated risk of death (relative ratio [RR_adj], 18.10 and 19.17, respectively) and mechanical ventilation (RR_adj, 2.56 and 5.71, respectively) than did cluster 1. Individuals in cluster 3 had an extended length of hospital stay (11 days), increased hospitalization direct costs (13,481.57 Chinese Yuan), and a higher risk of ICU admission (RR_adj, 2.14) than individuals in clusters 1 and 2. The decision tree assigned 90.8% of the participants correctly.

CONCLUSIONS

We identified 3 phenotypes with differential clinical and inflammatory characteristics associated with in-hospital adverse outcomes. These new phenotypes might have important and clinically relevant implications for the management of patients hospitalized for AEs.

Investigating the Role of Altered Systemic Albumin Concentration on the Disposition of Theophylline in Adult and Pediatric Patients with Asthma by Using the Physiologically Based Pharmacokinetic Approach

Theophylline is commonly used for the treatment of asthma and has a low hepatic clearance. The changes in plasma albumin concentration occurring in asthma may affect the exposure of theophylline. The aim of the presented work was to predict theophylline pharmacokinetics (PK) after incorporating the changes in plasma albumin concentration occurring in patients with asthma into a physiologically based pharmacokinetic (PBPK) model to see whether these changes can affect the systemic theophylline concentrations in asthma. The PBPK model was developed following a systematic model building approach using Simcyp. The predictions were performed initially in healthy adults after intravenous and oral drug administration. Only when the developed adult PBPK model had adequately predicted theophylline PK in healthy adults, the changes in plasma albumin concentrations were incorporated into the model for predicting drug exposure in patients with asthma. After evaluation of the developed model in the adult population, it was scaled to children on physiologic basis. The model evaluation was performed by using visual predictive checks and comparison of ratio of observed and predicted (R_obs/Pre) PK parameters along with their 2-fold error range. The developed PBPK model has effectively described theophylline PK in both healthy and diseased populations, as R_obs/Pre for all the PK parameters were within the 2-fold error limit. The predictions in patients with asthma showed that there were no significant changes in PK parameters after incorporating the changes in serum albumin concentration. The mechanistic nature of the developed asthma-PBPK model can facilitate its extension to other drugs. SIGNIFICANCE STATEMENT: Exposure of a low hepatic clearance drug like theophylline may be susceptible to plasma albumin concentration changes that occur in asthma. These changes in systemic albumin concentrations can be incorporated into a physiologically based pharmacokinetic model to predict theophylline pharmacokinetics in adult and pediatric asthma populations. The presented work is focused on predicting theophylline absorption, distribution, metabolism, and elimination in adult and pediatric asthma populations after incorporating reported changes in serum albumin concentrations to see their impact on the systemic theophylline concentrations.

Effect of Lavandula dentata extract on Ovalbumin-induced Asthma in Male Guinea Pigs

Asthma is an inflammatory disease of the lungs, and it causes oxidative stress. Lavandula dentata is an aromatic herb with anti-oxidative and anti-inflammatory activities. This study examined the activity of L. dentata extract on a guinea pig model of asthma. Adult males were divided into five groups: First group was control, second was asthma model induced by OVA, third was treated with L. dentata extract orally (300 mg/kg) for 21 days; the fourth was an asthma model with L. dentata extract (300 mg/kg) and fifth was treated with Tween 80 for 21 days. OVA treatment increased IgE, triglycerides, total cholesterol, glucose levels in serum, WBC count in blood and MDA in lungs. Also, OVA reduced SOD activity, GSH content in lungs, and GGT activity in serum (p<0.05). L. dentata extract treatment in asthma model reduced elevated IgE, triglycerides, total cholesterol, glucose levels in serum, and MDA in lungs (p<0.05), while it increased GSH content in lungs (p<0.05). These results suggest the possibility that L . dentata extract can exert suppressive effects on asthma, and may provide evidence that it is a useful agent for the treatment of allergic airway disease, it also limits oxidative stress induced by OVA. L. dentata extract appears to have hypolipidemic and hypoglycemic activities.

Blood-based bioenergetics: An emerging translational and clinical tool

Accumulating studies demonstrate that mitochondrial genetics and function are central to determining the susceptibility to, and prognosis of numerous diseases across all organ systems. Despite this recognition, mitochondrial function remains poorly characterized in humans primarily due to the invasiveness of obtaining viable tissue for mitochondrial studies. Recent studies have begun to test the hypothesis that circulating blood cells, which can be obtained by minimally invasive methodology, can be utilized as a biomarker of systemic bioenergetic function in human populations. Here we present the available methodologies for assessing blood cell bioenergetics and review studies that have applied these techniques to healthy and disease populations. We focus on the validation of this methodology in healthy subjects, as well as studies testing whether blood cell bioenergetics are altered in disease, correlate with clinical parameters, and compare with other methodology for assessing human mitochondrial function. Finally, we present the challenges and goals for the development of this emerging approach into a tool for translational research and personalized medicine.

Bioenergetic Differences in the Airway Epithelium of Lean Versus Obese Asthmatics Are Driven by Nitric Oxide and Reflected in Circulating Platelets

Aims: Asthma, characterized by airway obstruction and hyper-responsiveness, is more severe and less responsive to treatment in obese subjects. While alterations in mitochondrial function and redox signaling have been implicated in asthma pathogenesis, it is unclear whether these mechanisms differ in lean versus obese asthmatics. In addition, we previously demonstrated that circulating platelets from asthmatic individuals have altered bioenergetics; however, it is unknown whether platelet mitochondrial changes reflect those observed in airway epithelial cells. Herein we hypothesized that lean and obese asthmatics show differential bioenergetics and redox signaling in airway cells and that these alterations could be measured in platelets from the same individual. Results: Using freshly isolated bronchial airway epithelial cells and platelets from lean and obese asthmatics and healthy individuals, we show that both cell types from obese asthmatics have significantly increased glycolysis, basal and maximal respiration, and oxidative stress compared with lean asthmatics and healthy controls. This increased respiration was associated with enhanced arginine metabolism by arginase, which has previously been shown to drive respiration. Inducible nitric oxide synthase (iNOS) was also upregulated in cells from all asthmatics. However, due to nitric oxide synthase uncoupling in obese asthmatics, overall nitric oxide (NO) bioavailability was decreased, preventing NO-dependent inhibition in obese asthmatic cells that was observed in lean asthmatics. Innovation and Conclusion: These data demonstrate bioenergetic differences between lean and obese asthmatics that are, in part, due to differences in NO signaling. They also suggest that the platelet may serve as a useful surrogate to understand redox, oxidative stress and bioenergetic changes in the asthmatic airway.

No Associations Between Serum Lipid Levels or HOMA-IR and Asthma in Children and Adolescents: A NHANES Analysis

OBJECTIVE

Studies have reported inconsistent results on the associations between lipids and insulin resistance (IR) and asthma. The purpose of this study was to examine the associations between abnormal serum lipid levels and homeostatic model assessment-IR (HOMA-IR) and the presence of current asthma in children and adolescents.

METHODS

The United States National Health and Nutrition Examination Survey database from 1999 to 2012 was randomly searched for children (aged 3-11 years) and adolescents (aged 12-19 years) with and without asthma and with complete demographic and clinical data of interest. Logistic regression analyses were performed to examine associations between abnormal serum lipids, glucose and HOMA-IR and the current presence of asthma.

RESULTS

The data of 11,662 children (3 to 11 years of age) and 12,179 adolescents (12 to 19 years of age) were included in the analysis. The study group included 3,703 participants with asthma and 20,138 participants without asthma. The prevalence of self-reported current asthma was higher among participants aged between 3-11 years (52.9%) than among those aged between 12-19 years (50.7%). Multivariate analyses, after adjusting for sex, race, income-to-poverty ratio, low birth weight, prenatal maternal smoking, tobacco exposure, C-reactive protein level and body mass index Z-score, revealed no associations between elevated fasting plasma glucose, reduced high-density lipoprotein cholesterol, elevated low-density lipoprotein cholesterol, total cholesterol, triglycerides and HOMA-IR and the presence of current asthma in children or adolescents.

CONCLUSION

In this cross-sectional study, no association was found between abnormal serum lipids or HOMA-IR and the presence of current asthma in children or adolescents.

Association between lipid profile and the prevalence of asthma: a meta-analysis and systemic review

OBJECTIVE

To explore the association of asthma with serum levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol, and triglyceride.

METHODS

PubMed, Cochrane, and Embase databases were systematically searched through November 2015 using the following search terms: dyslipidemia, HDL, LDL, triglyceride, cholesterol, and asthma. Eligible studies included randomized controlled trials (RCTs), retrospective, cohort, and cross-sectional studies. Sensitivity analysis and publication bias were performed.

RESULTS

Twenty studies were included in the analysis, with a total 32,604 patients (3,458 in the asthma group and 29,146 in the control group). The pooled analysis found that the mean difference between groups was significantly higher in the asthma group for levels of LDL (6.026 mg/dL, 95% CI = 2.696-9.356, p < .001) and total cholesterol (8.161 mg/dL, 95% CI = 3.006-13.316, p = .002) compared with the control group. No association was observed between asthma and control groups for levels of HDL (mean difference = -0.728, 95% CI = -3.146-1.691, p = .555) or triglycerides (mean difference = 1.436, 95% CI = -2.768-5.640, p = .503).

CONCLUSIONS

Levels of LDL and total cholesterol were higher in patients with asthma than non-asthmatic patients.

Meta-analysis of the association between asthma and serum levels of high-density lipoprotein cholesterol and low-density lipoprotein cholesterol

BACKGROUND

The reported associations of blood lipid profiles with asthma are ambiguous.

OBJECTIVE

To explore the association between asthma and the serum levels of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C).

METHODS

A systematic search was performed in the PubMed, MEDLINE, Cochrane Library, and Chinese Biomedical Literature databases. Ten studies were identified. We divided these studies into 2 subgroups according to age: children (<18 years old) and adults (≥18 years old).

RESULTS

In children, the asthma group had lower HDL-C levels (weighted mean difference, -3.44; 95% confidence interval [CI], -5.83 to -1.04; P = .005) compared with the nonasthma group, whereas the serum levels of LDL-C in these 2 groups were not statistically different. In contrary, in adults, the asthma group had higher LDL-C levels (weighted mean difference, 8.95; 95% confidence interval, 3.55-14.35; P = .001) compared with the nonasthma group, whereas the HDL-C levels were not statistically different.

CONCLUSION

There is a significant association between asthma and the serum levels of HDL-C and LDL-C. Moreover, this association differs in children and adults.

Allergic lung inflammation promotes atherosclerosis in apolipoprotein E-deficient mice

Inflammation drives asthma and atherosclerosis. Clinical studies suggest that asthmatic patients have a high risk of atherosclerosis. Yet this hypothesis remains uncertain, given that Th2 imbalance causes asthma whereas Th1 immunity promotes atherosclerosis. In this study, chronic allergic lung inflammation (ALI) was induced in mice by ovalbumin sensitization and challenge. Acute ALI was induced in mice by ovalbumin and aluminum sensitization and ovalbumin challenge. Atherosclerosis was produced in apolipoprotein E-deficient (Apoe(-/-)) mice with a Western diet. When chronic ALI and atherosclerosis were produced simultaneously, ALI increased atherosclerotic lesion size, lesion inflammatory cell content, elastin fragmentation, smooth muscle cell (SMC) loss, lesion cell proliferation, and apoptosis. Production of acute ALI before atherogenesis did not affect lesion size, but increased atherosclerotic lesion CD4(+) T cells, lesion SMC loss, angiogenesis, and apoptosis. Production of acute ALI after atherogenesis also did not change atherosclerotic lesion area, but increased lesion elastin fragmentation, cell proliferation, and apoptosis. In mice with chronic ALI and diet-induced atherosclerosis, daily inhalation of a mast cell inhibitor or corticosteroid significantly reduced atherosclerotic lesion T-cell and mast cell contents, SMC loss, angiogenesis, and cell proliferation and apoptosis, although these drugs did not affect lesion area, compared with those that received vehicle treatment. In conclusion, both chronic and acute ALI promote atherogenesis or aortic lesion pathology, regardless whether ALI occurred before, after, or at the same time as atherogenesis. Antiasthmatic medication can efficiently mitigate atherosclerotic lesion pathology.

Emerging Comorbidities in Adult Asthma: Risks, Clinical Associations, and Mechanisms

Asthma is a heterogeneous disease with many phenotypes, and age at disease onset is an important factor in separating the phenotypes. Most studies with asthma have been performed in patients being otherwise healthy. However, in real life, comorbid diseases are very common in adult patients. We review here the emerging comorbid conditions to asthma such as obesity, metabolic syndrome, diabetes mellitus type 2 (DM2), and cardiac and psychiatric diseases. Their role as risk factors for incident asthma and whether they affect clinical asthma are evaluated. Obesity, independently or as a part of metabolic syndrome, DM2, and depression are risk factors for incident asthma. In contrast, the effects of comorbidities on clinical asthma are less well-known and mostly studies are lacking. Cross-sectional studies in obese asthmatics suggest that they may have less well controlled asthma and worse lung function. However, no long-term clinical follow-up studies with these comorbidities and asthma were identified. These emerging comorbidities often occur in the same multimorbid adult patient and may have in common metabolic pathways and inflammatory or other alterations such as early life exposures, systemic inflammation, inflammasome, adipokines, hyperglycemia, hyperinsulinemia, lung mechanics, mitochondrial dysfunction, disturbed nitric oxide metabolism, and leukotrienes.

Serum apolipoprotein A-I and large high-density lipoprotein particles are positively correlated with FEV1 in atopic asthma

RATIONALE

Although lipids, apolipoproteins, and lipoprotein particles are important modulators of inflammation, varying relationships exist between these parameters and asthma.

OBJECTIVES

To determine whether serum lipids and apolipoproteins correlate with the severity of airflow obstruction in subjects with atopy and asthma.

METHODS

Serum samples were obtained from 154 atopic and nonatopic subjects without asthma, and 159 subjects with atopy and asthma. Serum lipid and lipoprotein levels were quantified using standard diagnostic assays and nuclear magnetic resonance (NMR) spectroscopy. Airflow obstruction was assessed by FEV1% predicted.

MEASUREMENTS AND MAIN RESULTS

Serum lipid levels correlated with FEV1 only in the subjects with atopy and asthma. Serum levels of high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I (apoA-I) were positively correlated with FEV1 in subjects with atopy and asthma, whereas a negative correlation existed between FEV1 and serum levels of triglycerides, low-density lipoprotein (LDL) cholesterol, apolipoprotein B (apoB), and the apoB/apoA-I ratio. NMR spectroscopy identified a positive correlation between FEV1 and HDLNMR particle size, as well as the concentrations of large HDLNMR particles and total IDLNMR (intermediate-density lipoprotein) particles in subjects with atopy and asthma. In contrast, LDLNMR particle size and concentrations of LDLNMR and VLDLNMR (very-low-density lipoprotein) particles were negatively correlated with FEV1 in subjects with atopy and asthma.

CONCLUSIONS

In subjects with atopy and asthma, serum levels of apoA-I and large HDLNMR particles are positively correlated with FEV1, whereas serum triglycerides, LDL cholesterol, and apoB are associated with more severe airflow obstruction. These results may facilitate future studies to assess whether apoA-I and large HDLNMR particles can reduce airflow obstruction and disease severity in asthma.

Platelets from Asthmatic Individuals Show Less Reliance on Glycolysis

Asthma, a chronic inflammatory airway disease, is typified by high levels of T_H2-cytokines and excessive generation of reactive nitrogen and oxygen species, which contribute to bronchial epithelial injury and airway remodeling. While immune function plays a major role in the pathogenesis of the disease, accumulating evidence suggests that altered cellular metabolism is a key determinant in the predisposition and disease progression of asthma. Further, several studies demonstrate altered mitochondrial function in asthmatic airways and suggest that these changes may be systemic. However, it is unknown whether systemic metabolic changes can be detected in circulating cells in asthmatic patients. Platelets are easily accessible blood cells that are known to propagate airway inflammation in asthma. Here we perform a bioenergetic screen of platelets from asthmatic and healthy individuals and demonstrate that asthmatic platelets show a decreased reliance on glycolytic processes and have increased tricarboxylic acid cycle activity. These data demonstrate a systemic alteration in asthma and are consistent with prior reports suggesting that oxidative phosphorylation is more efficient asthmatic individuals. The implications for this potential metabolic shift will be discussed in the context of increased oxidative stress and hypoxic adaptation of asthmatic patients. Further, these data suggest that platelets are potentially a good model for the monitoring of bioenergetic changes in asthma.

Asthma: the role of low high-density-lipoprotein cholesterol in childhood and adolescence

BACKGROUND

Several studies have examined the relationship of asthma with serum dyslipidemia and reported positive, negative or no association. Most studies were limited by their cross-sectional design and the wide age range of the participants. In a cohort of children in Cyprus, we explored the association of asthma with serum high-density-lipoprotein cholesterol (HDL-C) at age 16-18 years (follow-up) independently of and in relation to HDL-C at age 11-12 years (baseline).

METHODS

In a case-control design, we recruited active asthmatics (AA; n = 68), current wheezers only (CWO; n = 123) and non-asthmatic controls (n = 660). Logistic regression models were used to evaluate associations of asthma with follow-up serum HDL-C and the role of baseline HDL-C.

RESULTS

At follow-up, mean HDL-C levels in AA and CWO patients were significantly lower than in the controls (47.9 and 49.7 vs. 53.4 mg/dl; p = 0.001 and p = 0.011). We observed significant associations of AA patients with low HDL-C (<15th percentile; OR 2.32, 95% CI 1.16-4.47) that remained significant after further adjustment for baseline HDL-C (OR 2.14, 95% CI 1.06-4.14). Stratification by baseline HDL-C indicated that the association was significant only in those with high baseline HDL-C (OR 2.40, 95% CI 1.03-5.20). Stratification by IgE sensitization showed that the association was pronounced only in subjects who were sensitized (OR 3.41, 95% CI 1.12-9.88).

CONCLUSIONS

Adolescent asthma is associated with low serum HDL-C independent of previous HDL-C levels in childhood. The association appears pronounced in those with a drop in HDL-C levels between childhood and adolescence and in those who have IgE sensitization.

Arachidonic acid intake and asthma risk in children and adults: a systematic review of observational studies

The effect of arachidonic acid (ARA) intake on asthma risk is unclear. The objective of the present review was to systematically evaluate available observational studies on the relationship between ARA exposure and asthma risk in children and adults. A PubMed search was conducted on 22 October 2013 and seventy-three publications were checked against predefined criteria for eligibility. To identify additional eligible publications, potentially relevant articles were searched from bibliographies of articles on ARA and asthma. A total of 2924 citations were scrutinised. Finally, fourteen articles were included. A quality assessment was conducted based on the reporting and methodological quality. A meta-analysis was not conducted; therefore, a qualitative assessment is presented. Three high-, two medium- and ten low-quality studies were reviewed. Eleven studies, including two high- and two medium-quality studies, did not find a significant association between ARA exposure and asthma risk. In contrast, one high-quality study indicated a significant trend toward reducing asthma risk in children with decreasing maternal ARA intake (P trend = 0·025), and one low-quality study reported a significant trend of increasing asthma risk with higher blood ARA levels (P trend = 0·007). In two low-quality studies, asthma patients had significantly lower blood ARA levels than controls (both P < 0·05). These studies did not sufficiently demonstrate any relationships between ARA exposure and asthma risk because of the limited number of studies and their methodological limitations. They seem to suggest that ARA exposure is not consistently associated with asthma risk. Nevertheless, further evidence is required to prove or disprove the association.

Increased IL-4 mRNA expression and poly-aromatic hydrocarbon concentrations from children with asthma

Background

Asthma is the most common chronic childhood disease. Imbalance of cytokines released from T helper cells and environmental factors, such as exposure to poly-aromatic hydrocarbon (PAH), play pivotal roles in the pathogenesis of asthma. The aim of this study was to compare the mRNA expression patterns of Interleukin (IL)-4, interferon (IFN)-γ and Acyl Co A long chain 3 (ACSL3) in peripheral blood leukocytes of children with and without asthma. To correlate the obtained mRNA data with serum IL-4, IFN-γ and PAH levels. Further, to determine the effect of in vivo exposure to PAH on mRNA expression of IL-4, IFN-γ and ACSL3 genes in a rat model.

Methods

A total of 170 children below 16 years (85 pediatric asthma patients and 85 matched healthy controls) were randomly selected from the Riyadh Cohort, Saudi Arabia. Gene expression analysis was performed using qRTPCR. Serum IL-4, IFN-γ and PAH were measured using LINCOplex (human multiplex immunoassay kit) and HPLC respectively.

Results

IL-4 mRNA expression was significantly increased (P < 0.05) in children with asthma compared to healthy control group whereas no differences were observed for either IFN-γ or ACSL3 mRNA. Similarly, serum IL- 4 and PAHs concentration was significantly higher as well in children with asthma in whom IFN-γ was also significantly lower. Results obtained in rats showed that exposure to the benzopyrene prototype PAH resulted in a 2.6 fold (P < 0.001) increased IL-4 mRNA expression in blood.

Conclusion

Peripheral blood IL-4 mRNA levels, serum concentration of this cytokine are elevated in children with asthma. Also, elevated levels of PAH were observed in children with asthma. Additionally, PAH administration in rodents resulted in an increased IL-4 mRNA which is supposed to partly mediate the inflammatory response noted in asthma.

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.

Oxidative stress and antioxidant deficiencies in asthma: potential modification by diet

The lungs of asthmatic patients are exposed to oxidative stress due to the generation of reactive oxygen and nitrogen species as a consequence of chronic airway inflammation. Increased concentrations of NO*, H2O2 and 8-isoprostane have been measured in exhaled breath and induced sputum of asthmatic patients. O2*-, NO*, and halides interact to form highly reactive species such as peroxynitrite and HOBr, which in turn cause nitration and bromination of protein tyrosine residues. Oxidative stress may also reduce glutathione levels and cause inactivation of antioxidant enzymes such as superoxide dismutase, with a consequent increase in apoptosis, shedding of airway epithelial cells and airway remodelling. The oxidant/antioxidant equilibrium in asthmatic patients may be further perturbed by low dietary intakes of the antioxidant vitamins C and E, selenium and flavonoids, with a consequent lowering of the concentrations of these and other non-dietary antioxidants such as bilirubin and albumin in plasma and airway epithelial lining fluid. Although supplementation with vitamins C and E appears to offer protection against the adverse effects of ozone, recent randomised, placebo-controlled trials of vitamin C or E supplements for patients with mild asthma have not shown significant benefits over standard therapy. However, genetic variation in glutathione S-transferase may influence the susceptibility of asthmatic individuals to oxidative stress and the extent to which they are likely to benefit from antioxidant supplementation. Long-term prospective trials are required to determine whether modification of dietary intake will benefit asthma patients and reduce the socio-economic burden of asthma in the community.

Low serum high-density lipoprotein cholesterol in childhood is associated with adolescent asthma

BACKGROUND

Whilst emerging evidence from animal and cell experiments has shown high-density lipoprotein cholesterol to have anti-inflammatory effects consistent with a protective role in asthma, human studies investigating the relationship of high-density lipoprotein cholesterol with asthma have produced conflicting results.

OBJECTIVE

To examine the association between serum lipids among Cypriot children aged 11-12 years and prevalence of asthma at age 15-17 years.

METHODS

In 3982 children, we assessed serum lipids, body mass index and maximal oxygen consumption at baseline (2001-2003) and explored associations with respiratory health at follow-up (2007) using multiple logistic regression models.

RESULTS

Lower levels of high-density lipoprotein cholesterol at age 11-12 years were found in subjects who reported ever asthma (58.2 vs. 60.0 mg/dL, P = 0.005) and active asthma (57.5 vs. 59.9 mg/dL, P = 0.010) in adolescence, in comparison with their respective reference groups. Total cholesterol, low-density lipoprotein and triglycerides had no association with any of the asthma outcomes. In contrast, with estimated odds ratios of 1.89 (95% CI 1.19-3.00) and 1.89 (95% CI 1.02-3.53), ever asthma and active asthma respectively appeared particularly pronounced among those who at baseline had high-density lipoprotein cholesterol <40 mg/dL, even after adjusting for potential confounders including body mass index and maximal oxygen consumption.

CONCLUSIONS & CLINICAL RELEVANCE

Low-serum high-density lipoprotein cholesterol in childhood is associated with an increased risk for asthma in adolescence, suggesting a potential role of this lipoprotein in the pathogenesis of paediatric asthma.

Novel relationship of serum cholesterol with asthma and wheeze in the United States

BACKGROUND

Cholesterol exerts complex effects on inflammation. There has been little investigation of whether serum cholesterol is associated with asthma, an inflammatory airways disease with great public health impact.

OBJECTIVE

To determine relationships between levels of 3 serum cholesterol measures (total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C], and non-HDL-C) and asthma/wheeze in a sample representative of the US population.

METHODS

Cross-sectional study of 7005 participants age >or=6 years from the 2005 to 2006 National Health and Nutrition Examination Survey.

RESULTS

Serum TC and non-HDL-C were lower in patients with current asthma than in subjects without current asthma in the overall population (TC, 188.5 vs 192.2 mg/dL; non-HDL-C, 133.9 vs 137.7 mg/dL; P < .05 for both), whereas HDL-C was not different. Adjusted odds ratios (ORs) from multivariate logistic regression per 1-SD increase of TC and non-HDL-C for current asthma were 0.92 (95% CI, 0.86-0.98) and 0.91 (95% CI, 0.85-0.98), respectively. On racial/ethnic stratification, these relationships reflect marked reductions unique to Mexican Americans (MAs; TC, 171.4 vs 189.3 mg/dL; P < .001; OR, 0.62; 95% CI, 0.48-0.80; non-HDL-C, 119.8 vs 137.9 mg/dL; P < .001; OR, 0.62; 95% CI, 0.48-0.79). Among MAs, the adjusted OR for wheeze requiring medical attention was 0.57 (95% CI, 0.43-0.75) for TC and 0.53 (95% CI, 0.33-0.85) for non-HDL-C. Relationships between cholesterol and asthma/wheeze were independent of body mass index and serum C-reactive protein, and similar between atopic and nonatopic participants.

CONCLUSION

Serum TC and non-HDL-C are inversely related to asthma in the US population, chiefly reflecting a relationship among MAs.

Metabolic and functional effects of glutamate intake in patients with chronic obstructive pulmonary disease (COPD)

BACKGROUND & AIMS

Patients with chronic obstructive pulmonary disease (COPD) often suffer from skeletal muscle weakness due to muscle wasting and altered muscle metabolism. Decreased muscle glutamate concentration in COPD is consistently reported and is associated with decreased muscle glutathione concentration and early lactic acidosis. We hypothesized that an increased availability of glutamate via glutamate ingestion increases muscle glutamate concentration leading to acute improvements in skeletal muscle energy metabolism and function.

METHODS

Two experiments were conducted. In experiment 1, in two groups of 6 male COPD patients (FEV(1): 44.8+/-3.4%pred) and 6 healthy controls, blood samples and muscle biopsies were taken at 0 and 80 min after repeated glutamate (30 mg/kg BW) or control ingestion (1.25 ml/kg BW), and after 20 min cycling at 50% peak workload. In experiment 2, in 10 COPD patients (FEV(1): 36.1+/-2.5%pred), the effect of the two drinks was tested on cycle endurance time and contractile quadriceps fatigue measured by magnetic stimulation before and after cycling at 75% peak workload.

RESULTS

Glutamate ingestion increased plasma (p<0.01) but not muscle glutamate concentration. Muscle total and reduced glutathione and plasma lactate concentration were not affected by glutamate ingestion. Glutamate ingestion did not influence contractile muscle fatigue and endurance time.

CONCLUSION

Continuous oral glutamate ingestion for 80 min did not lead to an acute effect on skeletal muscle substrate metabolism and muscle performance in COPD patients and in age-matched healthy controls.

The relation between dietary intake of individual fatty acids, FEV1 and respiratory disease in Dutch adults

BACKGROUND

A reduced dietary intake of n-3 fatty acids, in association with increased n-6 fatty acid intake, has been proposed as a potential aetiological factor for chronic obstructive pulmonary disease (COPD) and asthma. However, the relative importance of individual fatty acids within the n-3 and n-6 categories on this effect has not been widely investigated. We have studied the relation between individual fatty acid intakes, lung function and self-reported respiratory symptoms and diagnoses in a representative sample of more than 13,000 Dutch adults.

METHODS

Intake of individual fatty acids was estimated by a food frequency questionnaire and analysed in relation to measures of forced expiratory volume in 1 s (FEV1) and to questionnaire reported wheeze, asthma and COPD symptoms.

RESULTS

After adjusting for confounding, we found no protective association between individual n-3 fatty acid intakes and FEV1. Higher intakes of some n-6 fatty acids were associated with lower FEV1, this effect being most marked for c22:4 n-6 docosatetraenoic acid (reduction in FEV1 between the highest and lowest quintile of intake 54.5 ml (95% CI -81.6 to -27.4)). Most of the n-6 fatty acid effects interacted significantly with smoking, their effects being strongest in current smokers. Individual n-3 fatty acid intakes were generally associated with a higher risk of wheeze in the past year, but otherwise there was little or no association between fatty acid intake and wheeze, doctor diagnosed asthma or other respiratory symptoms.

CONCLUSIONS

A high intake of n-3 fatty acids does not appear to protect against COPD or asthma, but a high intake of several n-6 fatty acids is associated with a significant reduction in FEV1, particularly in smokers. These findings indicate that high dietary intake of n-6 fatty acids, rather than reduced n-3 intake, may have an adverse effect on lung health.

Corticosteroid-induced adverse events in adults: frequency, screening and prevention

Corticosteroids represent the most important and frequently used class of anti-inflammatory drugs and are the reference therapy for numerous neoplastic, immunological and allergic diseases. However, their substantial efficacy is often counter-balanced by multiple adverse events. These corticosteroid-induced adverse events represent a broad clinical and biological spectrum from mild irritability to severe and life-threatening adrenal insufficiency or cardiovascular events. The purpose of this article is to provide an overview of the available data regarding the frequency, screening and prevention of the adverse events observed in adults during systemic corticosteroid therapy (topically administered corticosteroids are outside the remit of this review). These include clinical (i.e. adipose tissue redistribution, hypertension, cardiovascular risk, osteoporosis, myopathy, peptic ulcer, adrenal insufficiency, infections, mood disorders, ophthalmological disorders, skin disorders, menstrual disorders, aseptic necrosis, pancreatitis) and biological (i.e. electrolytes homeostasis, diabetogenesis, dyslipidaemia) events. Lastly, data about the prescription of corticosteroids during pregnancy are provided. This review underscores the absence of data on many of these adverse events (e.g. lipodystrophy, dyslipidaemia). Our intent is to present to practitioners data that can be used in a practical way to both screen and prevent most of the adverse events observed during systemic corticosteroid therapy.

The effect of montelukast and low-dose theophylline on cardiovascular disease risk factors in asthmatics

BACKGROUND

Recent studies have implicated the 5-lipoxygenase/leukotriene (LT) pathway in cardiovascular disease (CVD), which may have important implications for asthmatics because several drugs that target this pathway are currently used to treat asthma. We sought to determine whether montelukast, a cysteinyl LT antagonist, and low-dose theophylline affected serum inflammatory and lipid CVD risk factors in a recently completed clinical trial in asthmatic patients.

METHODS

Patients were randomized to receive either montelukast (10 mg/d), theophylline (300 mg/d), or placebo. A baseline run-in period of 7 to 14 days was followed by treatment for 6 months. Serum levels of C-reactive protein (CRP), interleukin-6, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density cholesterol (HDL-C) were measured 1 month and 6 months after treatment.

RESULTS

Patients with moderate-to-severe asthma receiving montelukast (n = 60) had significantly lower serum CRP compared to placebo (n = 73) after 1 month (1.7 mg/L vs 3.2 mg/L, respectively; p < 0.006) and 6 months of treatment (2.3 mg/L vs 3.5 mg/L, respectively; p < 0.04). At both time points, serum levels of all lipids were also significantly lower in the montelukast and theophylline groups compared to placebo, but these effects were primarily observed in individuals who were also receiving inhaled corticosteroids as monotherapy for asthma.

CONCLUSIONS

Asthmatic patients receiving montelukast and, to some extent, low-dose theophylline have lower levels of CVD-associated inflammatory biomarkers and lipid levels. These observations suggest these asthma medications may have some beneficial value in asthmatics with respect to CVD risk, although the effects on HDL-C levels should also be taken into consideration.

Fatty acids in serum cholesteryl esters in relation to asthma and lung function in children

BACKGROUND

Dietary fatty acid intake has been proposed to contribute to asthma development with n-6 polyunsaturated fatty acids (PUFA) having a detrimental and n-3 PUFA a protective effect.

OBJECTIVE

The aim of our analysis was to explore the relationship between fatty acid composition of serum cholesteryl esters as marker of dietary intake and prevalence of asthma, impaired lung function and bronchial hyper-responsiveness in children.

METHODS

The study population consisted of 242 girls and 284 boys aged 8-11 years, living in Munich, Germany. Data were collected by parental questionnaire, lung function measurement and skin prick test according to the International Study of Asthma and Allergies in Childhood phase II protocol. Confounder-adjusted odds ratios (OR) with 95% confidence intervals (CI) were calculated for the association between quartiles of fatty acid concentration and health outcomes with the first quartile as reference.

RESULTS

n-3 PUFA: levels of eicosapentaenoic acid were not related to asthma and impaired lung function. Linolenic acid levels were positively associated with current asthma (OR for fourth quartile 3.35, 95% CI 1.29-8.66). Forced expiratory volume in 1 s (FEV(1)) values decreased with increasing levels of linolenic acid (p for trend=0.057). n-6 PUFA: there was a strong positive association between arachidonic acid levels and current asthma (OR(4th quartile) 4.54, 1.77-11.62) and a negative association with FEV(1) (P=0.036). In contrast, linoleic acid was negatively related to current asthma (OR(4th quartile) 0.34, 0.14-0.87) and FEV(1) values increased with increasing levels of linoleic acid (P=0.022). The ratio of measured n-6 to n-3 PUFA as well as levels of palmitic and oleic acid were not consistently related to asthma or lung function.

CONCLUSION

Our data do not support the hypothesis of a protective role of n-3 PUFA. Elevated arachidonic acid levels in children with asthma may be because of a disturbed balance in the metabolism of n-6 PUFA or may be secondary to inflammation in these patients.

Greater whole-body myofibrillar protein breakdown in cachectic patients with chronic obstructive pulmonary disease

BACKGROUND

Experimental studies indicate that greater skeletal muscle protein breakdown is a trigger for the cachexia that often is prevalent in chronic obstructive pulmonary disease (COPD).

OBJECTIVE

We compared myofibrillar protein breakdown (MPB) with whole-body (WB) protein breakdown (PB) in 9 cachectic COPD patients [x +/- SEM forced expiratory volume in 1 s (FEV(1)): 48 +/- 4% of predicted], 7 noncachectic COPD patients (FEV(1): 53 +/- 5% of predicted), and 7 age-matched healthy control subjects, who were matched by body mass index with the noncachectic patients.

DESIGN

After the subjects fasted overnight (10 h) and discontinued the maintenance medication, a primed constant and continuous infusion protocol was used to infuse L-[ring-(2)H(5)]-phenylalanine and L-[ring-(2)H(2)]-tyrosine to measure WB protein turnover and L-[(2)H(3)]-3-methylhistidine to measure WB MPB. Three arterialized venous blood samples were taken between 80 and 90 min of infusion to measure amino acid concentrations and tracer enrichments.

RESULTS

Body composition, WB protein turnover, and WB MPB did not differ significantly between the noncachectic COPD and control subjects. Cachectic COPD patients had lower fat mass and fat-free mass values (both: P < 0.01) than did the noncachectic COPD patients. WB MPB was significantly (P < 0.05) higher in the cachectic COPD group (18 +/- 3 nmol . kg(-1) . min(-1)) than in the combined control and noncachectic COPD groups (10 +/- 1 nmol . kg(-1) . min(-1)), but WB protein turnover did not differ significantly between the groups. Correlations with fat-free mass were significant (P < 0.05) for plasma glutamate and branched-chain amino acids, and that for WB MPB trended toward significance (P = 0.07).

CONCLUSION

Cachexia in clinically stable patients with moderate COPD is characterized by increased WB MPB, which indicates that myofibrillar protein wasting is an important target for nutritional and pharmacologic modulation.

Severe airway hyperresponsiveness in school-aged boys with a high body mass index

BACKGROUND

An association between obesity and asthma has been reported. The prevalence of airway hyperresponsiveness (AHR), results of skin prick tests, body mass index (BMI), and asthma symptoms were examined in schoolchildren.

METHODS

The results of BMI (kg/m2) determination, skin prick testing, spirometry, asthma questionnaires, and methacholine challenge tests were obtained in a cross-sectional survey of 667 schoolchildren. The methacholine concentration causing a 20% fall in FEV1 (PC20) was used as the threshold of AHR. If the PC20 was less than 16 mg/mL, the subject was considered to have methachloine mediated AHR.

RESULTS

The mean BMI was 17.1 +/- 0.09 kg/m2. The prevalence of AHR was 42.70%. The sensitization rate to common inhalant allergens was 30.3%. PC20 in children with BMIs > or = 17.1 kg/m2 was significantly lower than that in children with BMIs 17.1 kg/m2. The mean BMIs of boys and girls were not significantly different. The levels of PC20 by sex were not different. The children were grouped by sex into percentile of BMI. PC20 in boys was lower in the obese group than in the non-weight and overweight groups (p<0.05). PC20 in boys and girls with atopy was significantly lower than in those without atopy. In a multiple logistic regression model that included all of the children and adjusted for confounding variables, independent associations with AHR were seen with BMI, asthma symptoms, and atopy.

CONCLUSIONS

BMI had an association with AHR in school-age boys.

Serum nutrient markers and skin prick testing using data from the Third National Health and Nutrition Examination Survey

BACKGROUND

Diet nutrients and allergic sensitization both affect the development and severity of asthma, but the interrelationship between oral intake and allergic sensitization is not well characterized, although previous work suggests that a higher vitamin E intake may be protective against allergic sensitization.

OBJECTIVE

To determine whether serum levels of dietary antioxidants, lipids, and other nutrients are associated with the presence of allergen skin sensitization.

METHODS

Cross-sectional logistic regression analysis of 30 serum nutrient levels in relation to 10 skin test allergens in adults and children in the Third National Health and Nutrition Survey.

RESULTS

In adults, allergic skin sensitization was less common in participants with higher serum levels of vitamin E: the adjusted odds ratio (OR) per SD difference in vitamin E level was 0.93 (95% CI, 0.87-0.99). Two of the carotenoids, beta-cryptoxanthin and alpha-carotene, were also inversely associated with allergic skin sensitization (OR, 0.89; 95% CI, 0.83-0.95; and OR, 0.95; 95% CI, 0.91-0.99, respectively). Among adults, serum lycopene had a positive association with allergen sensitization. In youths, however, vitamin A was associated with an increased risk, and high-density lipoprotein cholesterol was associated with a decreased risk of allergic sensitization. The use of vitamin or mineral supplements had little effect on the magnitude of all reported associations.

CONCLUSION

Overall, there were no strong or consistent associations between serum levels of potentially antiallergic nutrients, and the occurrence of allergic skin sensitization in these data. However limited, findings suggest that increases in vitamin E, carotenoids, and high-density lipoprotein cholesterol may reduce the risk of allergic skin sensitization.

A case-control study of dietary and erythrocyte membrane fatty acids in asthma

BACKGROUND

Epidemiological evidence suggests that increased dietary omega-6 and reduced omega-3 fatty acid intake, may have contributed to the rising prevalence of asthma, but these hypotheses have not been tested in studies comparing both dietary intake and objective measures of polyunsaturated fatty acids.

OBJECTIVE

To assess whether a higher intake of omega-6 or a lower intake of omega-3 fatty acids increases the risk of asthma, by measuring dietary fatty acid intake by a food frequency questionnaire (FFQ) and erythrocyte membrane fatty acids, as an objective biomarker of intake.

METHODS

We have compared individual fatty acid intake estimated by FFQ and by mass spectrometry of fasting erythrocyte cell membranes in 89 cases of asthma and 89 community-matched controls.

RESULTS

The odds of asthma were increased in relation to intake of the omega-3 fatty acids eicosapentaenoic acid (odds ratio (OR) for difference between the 25th and 75th centiles of intake= 1.89, 95% CI 1.15-3.11) and docosahexaenoic acid (OR = 2.11, 95% CI 1.19-3.74). There was no evidence of any difference in erythrocyte membrane levels of omega-3 fatty acids, while the odds of asthma were reduced in relation to linoleic acid (omega-6) membrane levels (OR = 0.45, 95% CI 0.21-0.95).

CONCLUSION

These findings suggest that dietary omega-3 fatty acids do not play a major role in protecting against asthma, and that higher levels of erythrocyte membrane linoleic acid are associated with a lower risk of asthma.

Dietary micronutrients/antioxidants and their relationship with bronchial asthma severity

BACKGROUND

Because little is known about micronutrient/antioxidant intake and asthma severity, we investigated dietary intake and plasma/serum levels of micronutrients/antioxidants in a group of asthma patients with various degrees of severity, and compared the results with healthy subjects.

METHODS

A case control study was carried out on 118 asthma patients and 121 healthy subjects. The severity of the disease was classified by division of patients into four groups. Normal dietary micronutrient/antioxidant intake was estimated from a food frequency questionnaire. Plasma/serum levels of vitamins C, E, and A, selenium, magnesium, zinc, and platelet glutathione peroxidase (GSH-Px) activity were also determined.

RESULTS

No differences in daily micronutrient/antioxidant intake were seen between patients and healthy subjects. The severity of the disease showed no significant relationship with micronutrient/antioxidant intake. There were no differences in plasma/serum levels in any of the micronutrients/antioxidants between healthy subjects and asthmatics. Nor were any differences found between asthma groups in severity in the biochemical measures, except in platelet GSH-Px activity, which was significantly lower in the most severe groups.

CONCLUSIONS

In this study, we found no evidence of any association between micronutrient/antioxidant intake or plasma/serum levels of micronutrients/antioxidants and asthma. Reduction of platelet GSH-Px activity in the most severe patients suggests that these patients have a diminished capacity to restore part of the antioxidant defences.