ABSTRACT
BACKGROUND: The presence of lipids in alveolar macrophages (AMs) may impair their phagocytic response, and determine airway inflammation and obstruction. OBJECTIVE: To determine the factors such as severity of asthma, chronic cough, airway inflammation and obesity that may influence the presence of lipids in lung macrophages. METHODS: Bronchoalveolar lavage fluid (BALF) was obtained from 38 asthmatics (21 severe and 17 mild/moderate), 16 subjects with chronic cough and 11 healthy control subjects. The presence of lipids in macrophages was detected using an Oil-red-O stain and an index of lipid-laden macrophages (LLMI) was obtained. RESULTS: LLMI scores were higher in healthy subjects (median 48 [IQR 10-61]) and the severe asthma group (37 [11.5-61]) compared to mild/moderate asthmatics (7 [0.5-37]; p < 0.05 each). Subjects reporting a history of gastro-oesophageal reflux disease (GORD) had higher LLMI values (41.5 [11.3-138] versus 13 [0-39.3], p = 0.02). There was no significant correlation between LLMI and chronic cough, BAL cell differential counts, FEV1, FEV1/FVC or body mass index (BMI). CONCLUSIONS: The reduced LLMI in mild/moderate asthma may be related to lower incidence of GORD. However, this was not related to the degree of airflow obstruction, obesity or airway inflammation.
Subject(s)
Asthma/pathology , Bronchoalveolar Lavage Fluid/chemistry , Cough/pathology , Lipids/analysis , Macrophages, Alveolar/chemistry , Adult , Asthma/metabolism , Body Mass Index , Bronchoalveolar Lavage Fluid/cytology , Bronchoscopy , Case-Control Studies , Cell Count , Chronic Disease , Female , Humans , Male , Middle Aged , Obesity/complications , Risk Factors , Severity of Illness IndexABSTRACT
Severe asthmatics often exhibit poor control despite high doses of inhaled corticosteroids with or without systemic corticosteroids and suffer from persistent symptoms and/or recurrent exacerbations. Five to ten percentage of the asthmatic population falls within this category. Patients with severe asthma are a heterogeneous group and should be investigated to confirm the diagnosis, identify comorbidities, exclude alternative diagnoses, together with an evaluation of treatment adherence and side-effects from medications. Optimization of asthma medications and monitoring the control and pattern of asthma usually takes place over a period of 6 months. In patients with confirmed severe refractory asthma, further evaluation is needed in terms of detailed lung function, of airway and lung structure using high resolution computed tomographic scanning, and of airway inflammatory processes and biomarkers using induced sputum or bronchial biopsies. Patients with severe asthma are best investigated and managed with a multidisciplinary team. Severe asthma consists of different phenotypes that need defining. Investigation of severe asthma should bring into the open the various characteristics of the disease that could point to particular phenotype. Inclusion of investigations based on transcriptomics and proteomics should expand, improve classification and understanding of severe asthma, with the ultimate hope of finding more effective treatments and a step towards personalized medicine.
