title: In vitro production of tumor necrosis factor-alpha by human monocytes stimulated with lipopolysaccharide is positively correlated with increased blood monocytes after exposure to a swine barn.
abstract: Recently there has been interest in the air quality in and around intensive livestock production facilities, such as modern swine production barns, where agricultural workers and surrounding residents may be exposed to elevated levels of organic dusts. The health effects of these exposures are not completely understood. The study that is reported here is a component of a larger investigation of the relationships among the acute effects of high-concentration endotoxin exposure (swine barn dust), polymorphisms in the TLR4 gene, and respiratory outcomes following exposure to swine confinement buildings. The relationships among a mediator of acute lung inflammation, tumor necrosis factor alpha (TNF-alpha), and clinical responses to acute swine barn exposure were characterized. Analysis of the results showed that in vitro stimulation of human monocytes with as little as 1 ng/ml of lipopolysaccharide (LPS) produced a significant increase in the monocytes that produced TNF-alpha. Although the proportion of TNF-alpha-positive monocytes after in vitro stimulation with 1 ng/ml of LPS was not associated with gender or TLR4 genotype, it was positively associated with the concentration of monocytes in blood after barn exposure. Thus, these two responses to different forms of LPS exposure are significantly correlated, and more responsive monocytes in vitro indicate a forthcoming relative monocytosis, post barn exposure, which may initiate a cascade of chronic inflammation.
authors.affiliation: Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan Saskatoon, Saskatchewan, Canada.
authors.forename: P J
authors.initials: PJ
authors.lastname: Willson
authors.forename: T Talaei
authors.initials: TT
authors.lastname: Khozani
authors.forename: B H J
authors.initials: BH
authors.lastname: Juurlink
authors.forename: A
authors.initials: A
authors.lastname: Senthilselvan
authors.forename: D C
authors.initials: DC
authors.lastname: Rennie
authors.forename: V
authors.initials: V
authors.lastname: Gerdts
authors.forename: J
authors.initials: J
authors.lastname: Gawaziuk
authors.forename: D
authors.initials: D
authors.lastname: Schneberger
authors.forename: Lauranell H
authors.initials: LH
authors.lastname: Burch
authors.forename: J A
authors.initials: JA
authors.lastname: Dosman
mesh_terms: D000328:Adult; D000393:Air Pollutants; D000818:Animals; D004781:Environmental Exposure; D005260:Female; D006799:Housing, Animal; D006801:Humans; D007150:Immunohistochemistry; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D012129:Respiratory Function Tests; D013552:Swine; D051197:Toll-Like Receptor 4 / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
chemical_list: D000393:Air Pollutants; D008070:Lipopolysaccharides; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha