Airway inflammation and omega 3 PUFA in mild to moderate asthma

Asthma is a chronic inflammatory disease characterised by reversible airflow obstruction. Based on the relationship between a lack of exercise and chronic diseases, the latest guidelines from the Department of Health (DH) recommend physical activity across the whole population (DH, 2011). Exercise Induced Bronchoconstriction (EIB) is a ‘sub-type’ of asthma which affects approximately 90% of all individuals with asthma and an additional 10% of the healthy normal population (ATS/ACCP, 2003; Anderson & Kippelen, 2012); thus, EIB may be an important limiting factor for physical activity and an important ‘barrier to exercise’ for a number of individuals. Asthma is identified primarily by the occurrence of symptoms (wheezing breathlessness and dyspnoea), peak expiratory flow rates (PEF) and spirometry (Pulmonary Function tests – PFT). The current spirometry guidelines for the characterisation of asthma include a fixed criteria for the ratio between forced expiratory volume in one second and forced vital capacity (FEV1/FVC) (Miller et al., 2005b). This fixed criteria approach lacks specificity and is likely to misdiagnose approximately 20% of patients (Miller et al., 2011). The American Thoracic Society (ATS) and the European Respiratory Society (ERS) guidelines have acknowledged these concerns and have issued position statements for the use of a different approach using a ‘lower limit of normality’ (LLN) derived from a matched healthy population (Miller et al., 2009). Based on the fixed criteria, it has been shown that there is under diagnosis of participants with mild-moderate symptoms participants in the younger age group (Cerveri et al., 2009; Hansen et al., 2007; Miller et al., 2011; Roberts et al., 2006; Swanney et al., 2008). The currently available pharmacological therapies for asthma and EIB are effective (corticosteroids and bronchodilators), however long-term usage of these medications is associated with issues of tachyphylaxis and negative side effects (Barnes, 2010; GINA, 2011). There is some evidence from observational and intervention studies to suggest a beneficial effect of fish oil (comprising of omega-3 (n-3) polyunsaturated fatty acids (PUFAs)) in inflammatory diseases, (specifically asthma). Marine based n-3 PUFA have therefore been proposed as a possible complimentary/alternative therapy for asthma. The proposed anti-inflammatory effects of fish oil may be linked to a change in cell membrane composition. This altered membrane composition following fish oil supplementation [continues ...]