Pulmonary effects of biomass fuel indoor PM from rural India

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Project Summary About 3 billion people, half the worldwide population, are exposed to smoke from biomass fuel compared with 1 billion people who smoke tobacco, which suggests that exposure to biomass smoke might be the biggest risk factor for respiratory diseases such as chronic obstructive pulmonary disease (COPD), asthma, and respiratory infections globally. There is a disproportionate increase in COPD and asthma among non-smokers in rural India who use biomass for cooking. Ambient air particulate matter (PM) is well studied and linked to increased pulmonary oxidative stress and inflammation and causes greater respiratory diseases in the urban population; however, the effects of indoor PM due to biomass fuel on lungs and innate immune defense in the rural population remains unclear. The PI and co-investigators from JHU are collaborating with the two key pulmonologists from the India team who have established a rural cohort in Vadu village of Pune district (Maharashtra, India) that uses biomass fuel as their sole source of cooking fuel with high indoor PM. The PIs have collected indoor air PM (from rural houses with non-smokers). The main goal of this proposal is to characterize and compare the indoor PM from various biomass sources (cow dung, wood, and crop residue), and perform controlled mouse model studies using indoor PM to dissect the effects on lungs and innate immune response without the confounding effects of ozone and other gaseous components. The outcome from this study will help to develop future strategies for intervention in the rural population to reduce lung diseases. This proposal is an extension of the recently awarded FIRCA Eligible Award "Children's Environmental and Disease Prevention Research Center" P01 ES018176-01 (Project 3, 9/1/2009 - 8/31/2014). Project 3 (Mechanisms of asthma-dietary interventions against environmental triggers) and will test the hypothesis that antioxidants such as sulforaphane present in the diet can cause chemoprotection by activating the Nrf2 pathway to counteract oxidative stress and inflammation and protect against the pulmonary asthmatic response following ambient air particle exposure in mice. The specific aims in our current proposal provide a unique opportunity to test our hypothesis and to study the biological effects of indoor PM due to exposure to biomass fuel: SA1: To collect indoor PM and determine physicochemical characterization of different sources of biomass collected in rural homes. Homes in rural India use either cow dung, wood, crop residue, or a combination of the three for cooking. We have identified homes that will use only one biomass fuel source. The size and concentration of indoor PM in rural homes that use these different sources of biomass are being collected, and we will determine protein, endotoxin, metal and organic concentration in these indoor PM samples. This data will be helpful for characterizing the relative toxicity of each fuel source. SA2: To compare the effects of various sources of biomass-derived indoor PM collected in rural homes on lungs and innate immune response. We will test the hypothesis that indoor PM causes (a) oxidative stress, inflammation, and airway hyper-reactivity, and (b) inhibits the innate immune response. We will perform pulmonary aspiration of different indoor PM samples in A/J mice and measure markers of oxidative stress, inflammatory cells in bronchoalveolar lavage and lungs, cytokines and chemokines, and airway hyper- reactivity. We will also determine whether exposure of macrophages to indoor PM suppresses phagocytosis of bacteria. Although an inhalation exposure model is more realistic, airway instillation has been demonstrated to be a very effective model for comparing relative toxicity in mice where samples are limited. A/J mice were chosen because of their heightened sensitivity to airway challenges.