title: Characterization of lipopolysaccharides present in settled house dust.
abstract: The 3-hydroxy fatty acids (3-OHFAs) in lipopolysaccharides (LPS) play an important role in determining endotoxin activity, and childhood exposure to endotoxin has recently been associated with reduced risk of atopic diseases. To characterize the 3-OHFAs in house dust (HD), we used gas chromatography-mass spectrometry to assay 190 HD samples. Dust from beds, bedroom floors, family rooms, and kitchen floors was collected as part of a birth cohort study of childhood asthma (study 1) and a longitudinal study of home allergen and endotoxin (study 2). We also measured endotoxin activity with a Limulus assay and computed specific activity (endotoxin activity per nanomole of LPS). Longer-chain (C(16:0) and C(18:0)) 3-OHFAs were predominant in HD compared with short-chain (C(10:0), C(12:0), and C(14:0)) acids. Endotoxin activity was positively correlated with short-chain 3-OHFAs in both studies. In study 2, 3-OH C(16:0) was negatively correlated and 3-OH C(18:0) was not correlated with endotoxin activity, consistent with previous findings that the Limulus assay responds preferentially to LPS containing short-chain 3-OHFAs. Kitchen dust contained the highest concentrations of 3-OH C(10:0), the highest endotoxin activities, and the highest specific activities (P < 0.03). Bed dust contained the largest amounts of long-chain 3-OHFAs, the highest concentrations of LPS, and the lowest specific activities. Apartments had significantly different types of LPS (P = 0.03) compared with single-family homes in study 2. These data suggest that the Limulus assay may underestimate exposure to certain types of LPS. Because nontoxic LPS may have immune modulating effects, analysis of 3-OHFAs may be useful in epidemiologic studies.
authors.affiliation: Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA.
authors.forename: Ju-Hyeong
authors.initials: JH
authors.lastname: Park
authors.forename: Bogumila
authors.initials: B
authors.lastname: Szponar
authors.forename: Lennart
authors.initials: L
authors.lastname: Larsson
authors.forename: Diane R
authors.initials: DR
authors.lastname: Gold
authors.forename: Donald K
authors.initials: DK
authors.lastname: Milton
mesh_terms: D000818:Animals; D001513:Beds; D015331:Cohort Studies; D004391:Dust / Q000032:analysis*; D004731:Endotoxins / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D005430:Floors and Floorcoverings; D008401:Gas Chromatography-Mass Spectrometry; D006798:Housing; D006801:Humans; D008070:Lipopolysaccharides / Q000032:analysis*; D008137:Longitudinal Studies
chemical_list: D004391:Dust; D004731:Endotoxins; D005227:Fatty Acids; D008070:Lipopolysaccharides