How does endotoxin trigger inflammation in otitis media with effusion?
OBJECTIVE
The relationship among microorganisms, endotoxin, and inflammatory mediators in otitis media with effusion (OME) was examined.


METHODS
Analysis of 152 middle ear effusions aspirated at the time of ventilation tube insertion from children with OME.


METHODS
Effusion samples were cultured for pathogenic bacteria The two primary cytokines, interleukin-1beta (IL1beta) and tumor necrosis factor (TNFalpha), and the adhesion molecules, intercellular and vascular adhesion molecule (ICAM-1 and VCAM-1), were quantified using the enzyme-linked immunosorbent assay (ELISA) technique. Endotoxin concentration was measured with a limulus amebocyte lysate assay, and total protein concentration was quantified using the Biorad microassay.


RESULTS
The cultures of pathogenic bacteria were positive in 33 of the 152 effusions (22%), which contained more endotoxin and more of the primary cytokines than the 119 culture-negative effusions. Endotoxin and the primary cytokines were positively correlated, both in the whole material and in the sterile effusions alone. The adhesion molecules were positively correlated with each other, but not with endotoxin or the primary cytokines.


CONCLUSIONS
We found a positive correlation between endotoxin and the primary cytokines TNFalpha and IL1beta in culture-positive OME effusions as well as in culture-negative ones, suggesting endotoxin-induced local production of TNFalpha and IL1beta in the middle ear. ICAM-1 and VCAM-1 were also present in the middle ear, but their concentrations were not directly correlated to endotoxin or the primary cytokines.
Schousboe
L P
LP
Department of Otolaryngology, Aarhus University Hospital, Denmark. Schousboe@dadlnet.dk
Ovesen
T
T
Eckhardt
L
L
Rasmussen
L M
LM
Pedersen
C B
CB
D001424:Bacterial Infections / Q000276:immunology* / Q000382:microbiology; D002675:Child, Preschool; D004432:Ear, Middle / Q000276:immunology / Q000382:microbiology; D004731:Endotoxins / Q000276:immunology*; D005260:Female; D006801:Humans; D007223:Infant; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007375:Interleukin-1 / Q000378:metabolism*; D008297:Male; D010034:Otitis Media with Effusion / Q000276:immunology* / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
D004731:Endotoxins; D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1