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Tu sửa đường hàng không nhỏ là một nguyên nhân quan trọng của bệnh phổi tắc nghẽn mãn tính (COPD) hút thuốc lá. Tỷ lệ mắc COPD trong đối tượng tiếp xúc mãn tính cấp độ cao hạt không khí ô nhiễm (ví dụ, vấn đề hạt) xuất hiện để được tăng lên, và các nghiên cứu hình thái đã chỉ ra rằng vấn đề hạt (PM) sản xuất tu sửa đường hàng không nhỏ là cấu trúc tương tự như ở người hút thuốc lá. Các nghiên cứu thực nghiệm cho thấy rằng PM vào bức tường đường hàng không và đề nghị rằng. | 4 Particulate Air Pollutants and Small Airway Remodeling Andrew Churg Department of Pathology University of British Columbia CONTENTS 4.1 Summary.75 4.2 Epidemiology.75 4.3 Anatomic Changes in the Airways of Humans with Chronically High-PM Exposure.76 4.4 Experimental Studies on PM and Airway Wall Remodeling.78 4.5 Interactions of PM and Ozone.81 4.6 Functional Consequences and Perspective.84 Acknowledgment.85 References.85 4.1 SUMMARY Small airway remodeling is an important cause of chronic obstructive pulmonary disease COPD in cigarette smokers. The incidence of COPD in subjects exposed to chronically high levels of particulate air pollutants i.e. particulate matter appears to be increased and morphologic studies have shown that particulate matter PM produces small airway remodeling that is structurally similar to that seen in cigarette smokers. Experimental studies show that PM enters airway walls and suggest that the most important component of airway remodeling increased airway wall fibrous tissue is driven by oxidants and iron released from PM particles. Release of the fibrogenic cytokine TGFb1 again through an oxidant mechanism also appears to be involved. These processes lead to thickened fibrotic and distorted small airways that have increased resistance to flow producing the clinical picture of COPD. Humans are exposed to both PM and ozone in vivo and experimental data imply that this combination of exposures potentiates airway wall remodeling but information on this question in humans is lacking. 4.2 EPIDEMIOLOGY Although cigarette smoking is by far the most important cause of COPD there is somewhat limited evidence to suggest that chronic exposure to high levels of particulate air pollutants i.e. PM may also cause chronic airflow obstruction reviewed by Sunyer 2001 . The most extensive studies are those of Abbey and colleagues Abbey et al. 1991 1995 1998 1999 Beeson et al. 1998 who examined a cohort of nearly 4000 nonsmoking Seventh-Day Adventists in .
