Eicosapentaenoic acid is more effective than docosahexaenoic acid in inhibiting proinflammatory mediator production and transcription from LPS-induced human asthmatic alveolar macrophage cells

Background & aims: The purpose of the study was to determine which of the active constituents of fish oil, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), is most effective in suppressing proinflammatory mediator generation and cytokine expression from LPS-stimulated human asthmatic alveolar macrophages (AMΦ). Methods: The AMΦ were obtained from twenty-one asthmatic adults using fiberoptic bronchoscopy. Cells were pretreated with DMEM, pure EPA, an EPA-rich media (45% EPA/10% DHA), pure DHA, a DHArich media (10% EPA/50% DHA) or Lipovenos® (n-6 PUFA), and then exposed to Dulbecco’s Modified Eagle’s Medium (DMEM) (-) or LPS (+). Supernatants were analyzed for leukotriene (LT)B4, prostaglandin (PG)D2, tumor necrosis factor (TNF)-α and interleukin (IL)-1β production. Detection of TNF-α and IL-1β mRNA expression levels was quantified by reverse transcriptase polymerase chain reaction. Results: 120 μM pure EPA and EPA-rich media significantly (p < 0.05) suppressed TNF-a and IL-1b mRNA expression and the production of LTB4, PGD2 and TNF-a and IL-1b in LPS-stimulated primary AMφ cells obtained from asthmatic patients to a much greater extent than 120 mM pure DHA and DHA-rich media respectively. Conclusions: This study has shown for the first time that EPA is a more potent inhibitor than DHA of inflammatory responses in human asthmatic AMΦ cells

Ascorbic acid supplementation attenuates exercise-induced bronchoconstriction in patients with asthma

SummaryBackgroundPrevious research has shown that diet can modify the bronchoconstrictor response to exercise in asthmatic subjects.ObjectiveDetermine the effect of ascorbic acid supplementation on pulmonary function and several urinary markers of airway inflammation in asthmatic subjects with exercise-induced bronchoconstriction (EIB).MethodsEight asthmatic subjects with documented EIB participated in a randomized, placebo controlled double-blind crossover trial. Subjects entered the study on their usual diet and were placed on either 2 weeks of ascorbic acid supplementation (1500mg/day) or placebo, followed by a 1-week washout period, before crossing over to the alternative diet. Pre- and post-exercise pulmonary function, asthma symptom scores, fraction of exhaled nitric oxide (FENO), and urinary leukotriene (LT) C4–E4 and 9α, 11β-prostagladin (PG)F2] were assessed at the beginning of the trial (usual diet) and at the end of each treatment period.Results: The ascorbic acid diet significantly reduced (p<0.05) the maximum fall in post-exercise FEV1 (−6.4±2.4%) compared to usual (−14.3±1.6%) and placebo diet (−12.9±2.4%). Asthma symptoms scores significantly improved (p<0.05) on the ascorbic acid diet compared to the placebo and usual diet. Post-exercise FENO, LTC4–E4 and 9α, 11β-PGF2 concentration was significantly lower (p<0.05) on the ascorbic acid diet compared to the placebo and usual diet.ConclusionAscorbic acid supplementation provides a protective effect against exercise-induced airway narrowing in asthmatic subjects

Randomized Controlled Trial of Fish Oil and Montelukast and Their Combination on Airway Inflammation and Hyperpnea-Induced Bronchoconstriction

Both fish oil and montelukast have been shown to reduce the severity of exercise-induced bronchoconstriction (EIB). The purpose of this study was to compare the effects of fish oil and montelukast, alone and in combination, on airway inflammation and bronchoconstriction induced by eucapnic voluntary hyperpnea (EVH) in asthmatics. In this model of EIB, twenty asthmatic subjects with documented hyperpnea-induced bronchoconstriction (HIB) entered a randomized double-blind trial. All subjects entered on their usual diet (pre-treatment, n = 20) and then were randomly assigned to receive either one active 10 mg montelukast tablet and 10 placebo fish oil capsules (n = 10) or one placebo montelukast tablet and 10 active fish oil capsules totaling 3.2 g EPA and 2.0 g DHA (n = 10) taken daily for 3-wk. Thereafter, all subjects (combination treatment; n = 20) underwent another 3-wk treatment period consisting of a 10 mg active montelukast tablet or 10 active fish oil capsules taken daily. While HIB was significantly inhibited (p0.017) between treatment groups; percent fall in forced expiratory volume in 1-sec was −18.4±2.1%, −9.3±2.8%, −11.6±2.8% and −10.8±1.7% on usual diet (pre-treatment), fish oil, montelukast and combination treatment respectively. All three treatments were associated with a significant reduction (p0.017) in these biomarkers between treatments. While fish oil and montelukast are both effective in attenuating airway inflammation and HIB, combining fish oil with montelukast did not confer a greater protective effect than either intervention alone. Fish oil supplementation should be considered as an alternative treatment for EIB

Eicosapentaenoic acid is more effective than docosahexaenoic acid in inhibiting proinflammatory mediator production and transcription from LPS-induced human asthmatic alveolar macrophage cells

This paper was published in the journal, Clinical Nutrition [© Elsevier Ltd and European Society for Clinical Nutrition and Metabolism] and the definitive version is available at: http://dx.doi.org/10.1016/j.clnu.2008.10.012Background & aims: The purpose of the study was to determine which of the active constituents of fish oil, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), is most effective in suppressing proinflammatory mediator generation and cytokine expression from LPS-stimulated human asthmatic alveolar macrophages (AMΦ). Methods: The AMΦ were obtained from twenty-one asthmatic adults using fiberoptic bronchoscopy. Cells were pretreated with DMEM, pure EPA, an EPA-rich media (45% EPA/10% DHA), pure DHA, a DHArich media (10% EPA/50% DHA) or Lipovenos® (n-6 PUFA), and then exposed to Dulbecco’s Modified Eagle’s Medium (DMEM) (-) or LPS (+). Supernatants were analyzed for leukotriene (LT)B4, prostaglandin (PG)D2, tumor necrosis factor (TNF)-α and interleukin (IL)-1β production. Detection of TNF-α and IL-1β mRNA expression levels was quantified by reverse transcriptase polymerase chain reaction. Results: 120 μM pure EPA and EPA-rich media significantly (p < 0.05) suppressed TNF-a and IL-1b mRNA expression and the production of LTB4, PGD2 and TNF-a and IL-1b in LPS-stimulated primary AMφ cells obtained from asthmatic patients to a much greater extent than 120 mM pure DHA and DHA-rich media respectively. Conclusions: This study has shown for the first time that EPA is a more potent inhibitor than DHA of inflammatory responses in human asthmatic AMΦ cells