Role of CD163+ Macrophages in Organic Dust Exposure: A Study on Porcine Blood and Lungs
Description
CD163, a scavenger surface receptor of alveolar macrophages (AMs), facilitates pathogen recognition, however, its specific role under organic dust (OD) exposure in swine confinement remains unclear. We hypothesized that continuous OD exposure within swine barns activates CD163+ AMs and promotes their proinflammatory responses. To investigate our hypothesis, macrophages were isolated from porcine bronchoalveolar lavage fluid (BALF) and blood, exposed to fluorescent-FITC-beads and stained with CD163 and CD14 markers. Supernatants and cells were analyzed for oxidative stress, inflammation, and phagocytic activity via immunoassays and flow cytometry. Data were analyzed using Two- way ANOVA (p-value < 0.05) Results elevated CD14+CD163+ expression with increasing phagocytic activity in indoor AMs. However, CD14+CD163+ expression was higher in blood macrophages of outdoor versus indoor pigs. Bead uptake by BALF AMs of indoor pigs produced higher nitric oxide and TNF-α levels. Conversely, interleukin (IL)-1β and IL-6 production was higher in BALF AMs of outdoor pigs. This study suggests exposure to OD in indoor environments may increase phagocytic activity by CD163+ macrophages, oxidative stress, and inflammatory markers, which potentially contributes to the pathogenesis of chronic bronchitis among agricultural workers. Future studies could focus on these implications for humans.