Cell Size of Alveolar Macrophages: An Interspecies Comparison

Abstract

Alveolar macrophages (AM) play a critical role in the removal of inhaled particles or fibers from the lung. Species differences in AM size may affect the number and size range of particles/fibers that can be actually phagocytized and cleared by AM. The purpose of this study was to compare the cell size of rat, hamster, monkey, and human AM by selective flow cytometric analysis of cell volume. Resident AM from CD rats, Syrian golden hamsters, cynomolgus monkeys, and nonsmoking, healthy human volunteers were harvested by standard bronchoalveolar lavage procedures. Morphometric analysis of AM was performed using a flow cytometer that generates volume signals based on the Coulter-type measurement of electrical resistance. We found that hamster and rat AM had diameters of 13.6±0.4 pm (n=8) and 13.1 ±0.2 pm (n=12), respectively. Comparatively, the AM from monkeys (15.3 ± 0.5 pm, n = 7) and human volunteers (21.2 ± 0.3 pm, n = 10) were larger than those from rats and hamsters. The AM from humans were significantly larger (p <0.05) than those from all other species studied, corresponding to a 4-fold larger cell volume of human AM (4990 ± 174 pm3) compared to hamster (1328 ± 123 pm3) and rat (1166±42 pm3) AM. In summary, we have found marked species differences in the cell size of AM. We suggest that the number and size range of particles/fibers that can be phagocytized and cleared by AM may differ among species due to inherent or acquired species differences in AM cell size.

Cytomorphological and Morphometric Analysis of 22 Cases of Rosai-Dorfman Disease: A Large Series from a Tertiary Care Centre

“…Alcohol-fixed FNAC smears are therefore better suited than histological sections to perform such an assessment. The average reported diameter of monocyte/macrophages and alveolar macrophages is 15-30 µm and 21.2 µm, respectively [36,37]. In our study, the mean nuclear diameter of histiocytes of reactive lymph nodes was significantly smaller than that of RDD histiocytes (10.1 vs. 16.7 µm, p < 0.01).…”

A review on the importance of metals and metalloids in atmospheric dust and aerosol from mining operations

“…Coarse particles, such as those resulting from ore crushing and grinding, deposit in the upper respiratory system and are swallowed and go through the digestive system where contaminants may be absorbed, depending on their bioavailability. In contrast, fine particles, such as those originating from smelting operations, are respired deep into the lungs where they can be transported directly to the blood stream (Krombach et al, 1997; Park and Wexler, 2008; Valiulis et al, 2008). In addition, dermal deposition and incidental ingestion are exposure mechanisms that are related to particle size.…”

“…From a study on the bioavailability of Pb according to size fraction from ambient aerosols around a Pb smelter, Spear et al (1998) found that not only was the highest percentage of Pb concentration in the fine size fraction, but also it contained the largest percentage of bio-available Pb. Therefore, finer size fraction particles that deposit in the lungs and are transported to the blood stream via macrophages have a higher bioavailability (Krombach et al, 1997) and have been shown to contain the largest concentrations of metals and metalloids from smelter emissions (Spear et al, 1998; Csavina et al, 2011). …”

Hygroscopic Properties and Respiratory System Deposition Behavior of Particulate Matter Emitted By Mining and Smelting Operations

“…When reaching the lungs, such particles can then be transported to the blood stream by macrophages while contaminants such as metals and metalloids can diffuse into the blood stream 26-27 .…”