Macrophages alveolar region

In addition to releasing elastase into the alveolar regions of the lung, macrophages and neutrophils also disrupt the potential protease-anti-protease balance of the lung through other functions. For example, both cells can secrete myeloperoxidase and hydrogen peroxide, which can cata-... 

With prolonged exposure to particulate matter at sufficiently high concentrations, the particulate matter continuously deposited in the alveolar spaces can trigger a sustained inflammatory reaction. The inflammation can alter particle clearance, initially increase the rate of clearance, and then later canse inhibition of clearance. This, in turn, intensifies the inflammatory reaction, which further impairs clearance and enhances the rate of particle accumulation in the alveolar region. Some of these particles are found in the interstitial areas and others in the alveolar spaces, where aggregates of macrophages, particles, and proteinaceous material may be observed. Adjacent epithelial cells become hypertrophic, hyperplastic, and occasionally, metaplastic. Freqnently, bronchiolar epithelium may appear to be extending down into the alveoli. This pattern of particle-indnced overload disease has been described in detail in rats chronically exposed to diesel exhaust or carbon black particles (39,40). The extent to which similar lesions are produced in humans exposed to similar levels of diesel soot or carbon black is not well understood. 

In studies on rabbit alveolar macrophage cultures, Waters and coworkers (133) presented data suggesting that vanadium oxides may adversely affect pulmonary defense. The cytotoxicity of the oxides studied were directly related to their solubility, i.e., V2O5 > V203 > V02. Ambient vanadium concentrations in urban regions have been reported to correlate with mortality incidence from bronchitis and pneumonia, especially in males (134). Likewise, industrial exposure to airborne manganese has been shown to correlate with increased incidence of bronchitis, caused in part by increased susceptibility to infection (135). 

Alveolar macrophages account for 3% of cells in the A region. These phagocytic cells scavenge and transport particulate matter to the lymph nodes and the mucociliary escalator (see below). 

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