Dietary Cholesterol Enhances Pulmonary Eosinophilic Inflammation in a Murine Model of Asthma

BACKGROUND: Epidemiological studies have suggested that the dietary pattern may be associated with the prevalence of asthma. We previously reported that an increased intake of foods of animal origin was associated with the occurrence of allergic rhinitis and asthma in adolescents. Here we examined the effect of dietary cholesterol in a murine model of allergic pulmonary inflammation. METHODS: Weanling C57BL/6 mice were fed a control diet containing 0.02% cholesterol or a diet supplemented with 1% or 2% cholesterol. Four weeks later the mice were sensitized with intraperitoneal ovalbumin (OVA) followed by OVA or saline inhalation 2 weeks later. OVA aerosol-induced inflammation was significantly enhanced by dietary supplementation of 1% or 2% cholesterol. RESULTS: Among OVA-challenged mice, leukocyte numbers, particularly those of eosinophils, in the bronchoalveolar space increased by 3- to 5-fold with the cholesterol supplement. Among OVA aerosol-challenged mice, the levels of interleukin-5 and cysteinyl leukotrienes in the bronchoalveolar lavage fluid were significantly higher in those fed the 2% cholesterol diet compared with mice on the control diet. CONCLUSIONS: Dietary cholesterol may enhance pulmonary allergic inflammation.