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Byline: Britt-Marie Larsson (1), Kjell Larsson (1), Per Malmberg (1), Lena Palmberg (1) Abstract: Background and Objective: Inhalation of dust from swine confinement buildings results in an acute inflammatory reaction in the respiratory tract. The dust has a high microbial content, dominated by Gram positive bacteria. The aim of the present study was to evaluate the significance of bacteria in the induction of IL-6 and IL-8 release from respiratory epithelial cells and alveolar macrophages. The results would give an indication to what extent the bacteria contribute to the toxic inflammation following exposure to swine dust. Methods: Epithelial cells from a human lung carcinoma cell line (A549) and human alveolar macrophages obtained from healthy subjects by bronchoalveolar lavage, were stimulated with swine dust, LPS, one Gram negative and four Gram positive bacteria strains. The dose-response release of IL-6 and IL-8 were studied. In addition, a bacteria-free supernatant was prepared from each strain and used for stimulation. Results: With a few exceptions, a dose-dependent IL-6 and IL-8 release was demonstrated from both cell types after stimulation with bacteria. In epithelial cells, Escherichia coli was the most potent bacteria at the highest concentration of 400 bacteria/cell regarding secretion of both IL-6 and IL-8 (P &lt 0.001), followed by Staphylococcus hominis and Staphylococcus lentus. In alveolar macrophages, S. lentus was the most potent strain (P &lt 0.001) in inducing cytokine release (P &lt 0.001), followed by S. hominis and E. coli concerning IL-6 secretion or Micrococcus luteus and E. coli with respect to IL-8 secretion (P &lt 0.001). Differences in potency between the various bacteria could be demonstrated, both within the two cell types as well as between the epithelial cells and macrophages. Bacteria-free supernatants were also able to induce cytokine release in both cell types. In macrophages the supernatants were even more potent stimuli than whole bacteria. Conclusions: The results indicate that bacteria or bacterial products could be an important contributing factor to the inflammatory reaction following exposure to swine dust. Author Affiliation: (1) Department of Occupational Medicine, National Institute for Working Life, S-171 84, Solna, Sweden Article History: Registration Date: 30/09/2004

Byline: Torbjorn S. Haugen (1), Britt Nakstad (1), Torstein Lyberg (1) Abstract: We have studied the expression of tissue factor (TF) and fibrinopeptide A (FPA) generation as well as the release capacity of TNF-[alpha], IL-1[beta], and IL-6 in density-defined subpopulations of alveolar macrophages (AM) and monocytes (Mo). TF was equally expressed on all AM subpopulations and Mo, while the FPA-forming capacity was at the same level in low density AM as in Mo and was significantly (P &lt 0.05) higher in low density AM than in high density AM. The lipopolysaccharide (LPS)-induced release of TNF-[alpha] was higher (P &lt 0.05) in high density AM than in low density AM and in Mo. IL-1[beta] release was undetectable in unstimulated AM and in LPS-stimulated low density AM, while the LPS-induced IL-1[beta] release in high density AM was low compared to the levels demonstrated in Mo. LPS-stimulated IL-6 release was not distinctively different in the AM subpopulations and Mo. The presented study showed that FPA generation and LPS-stimulated TNF-[alpha] release were dependent on the density (i.e., maturity) of AM. This implies that a skewed distribution of AM subpopulations induced by disease processes may profoundly influence the inflammatory reactions, including extravascular activation of coagulation. Author Affiliation: (1) Research Forum, Ullevaal University Hospital, Oslo, Norway Article History: Registration Date: 14/10/2004