Ghio Andrew J, Stewart Matthew, Sangani Rahul G, Pavlisko Elizabeth N, Roggli Victor L
US Environmental Protection Agency, Research Triangle Park, NC, United States.
Department of Environmental Health Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States.
Front Public Health. 2025 Apr 9;13:1558723. doi: 10.3389/fpubh.2025.1558723. eCollection 2025.
The retention of occupational and environmental particles in the lung is a primary determinant of biological effects. In the distal respiratory tract, particle clearance includes phagocytosis by alveolar macrophages (AMs), migration to the terminal bronchiole, and transport of AMs and particles by the mucociliary escalator. With increasing particle exposure, a focal collection of particle-laden macrophages results at the respiratory bronchiole (RB) which is that site in the clearance pathway demanding the greatest traverse by these cells after a commencement from the alveoli. With the greatest particle doses, there is "particle overload" and impaired mobility which is reflected by an excess accumulation of particle-laden macrophages throughout the RBs, alveolar ducts, and alveoli. With deposition of fibrous particles in the distal respiratory tract, the AM is unable to extend itself to enclose fibers with a major diameter of 10-20 microns or longer resulting in "frustrated phagocytosis" and longer retention times. Clearance pathways for particles are shared. There can be a summation of particle exposures with exhaustion in the capacity of the AMs for transport. Cigarette smoking (CS) is the greatest particle challenge humans encounter. Associated with its enormous magnitude, CS profoundly impacts the clearance pathways and subsequently interacts with other particle exposures to increase biological effects. Interstitial lung disease, pulmonary function, chronic obstructive pulmonary disease, infections, lung cancer, and mortality can be altered among smokers exposed to occupational and environmental particles (e.g., silica, coal mine dust, air pollution particles, other particles, and asbestos). It is concluded that both decreasing CS and controlling particle exposures are of vital importance in occupational and environmental lung disease.
职业和环境颗粒物在肺部的潴留是生物效应的主要决定因素。在远端呼吸道，颗粒物清除包括肺泡巨噬细胞（AM）的吞噬作用、向终末细支气管的迁移以及AM和颗粒物通过黏液纤毛转运系统的运输。随着颗粒物暴露增加，在呼吸性细支气管（RB）会形成充满颗粒物的巨噬细胞的局灶性聚集，这是清除途径中这些细胞从肺泡开始后需要经过最长行程的部位。在最大颗粒物剂量情况下，会出现“颗粒物过载”和迁移能力受损，表现为充满颗粒物的巨噬细胞在整个RB、肺泡管和肺泡中过度积聚。当纤维性颗粒物沉积在远端呼吸道时，AM无法伸展自身包裹直径10 - 20微米或更长的纤维，导致“吞噬受挫”和更长的潴留时间。颗粒物的清除途径是共享的。颗粒物暴露可能会累加，导致AM的转运能力耗尽。吸烟（CS）是人类面临的最大颗粒物挑战。由于其暴露量巨大，CS会深刻影响清除途径，随后与其他颗粒物暴露相互作用，增加生物效应。在接触职业和环境颗粒物（如二氧化硅、煤矿粉尘、空气污染颗粒物、其他颗粒物和石棉）的吸烟者中，间质性肺病、肺功能、慢性阻塞性肺疾病、感染、肺癌和死亡率可能会发生改变。得出的结论是，减少吸烟和控制颗粒物暴露在职业和环境性肺病中都至关重要。
