Expression of adhesion molecules in nonallergic chronic sinusitis

Differential expression of adhesion molecules by sinonasal fibroblasts among control and chronic rhinosinusitis patients

BACKGROUND

Chronic rhinosinusitis (CRS) is characterized by inflammatory cell migration into sinus tissue with resultant inflammation fueled by a milieu of cytokines. Fibroblasts may contribute to inflammation through expression of leukocyte adhesion molecules such as vascular cell adhesion molecule (VCAM) and intercellular adhesion molecule (ICAM). VCAM attracts eosinophils and mast cells contributing to Th2 skewing, and ICAM attracts neutrophils and to a lesser degree, eosinophils, and contributes to mixed Th1/Th2 skewing. The purpose of this study was to compare sinus fibroblast adhesion molecule expression ex vivo among CRS subtypes and in vitro after cytokine stimulation.

METHODS

Sinus biopsy specimens were taken from control patients (n = 13), CRS without nasal polyposis (CRSsNP, n = 6), and CRS with nasal polyposis (CRSwNP, n = 15). ex vivo levels of VCAM and ICAM were measured by flow cytometry from single cell suspensions of tissue biopsy specimens. Changes in VCAM and ICAM expression to cytokine exposure were assessed using in vitro cultured sinonasal fibroblasts treated with tumor necrosis factor (TNF)-α, interleukin (IL)-4, or interferon (IFN)-γ.

RESULTS

ex vivo VCAM expression was lowest in controls, higher in CRSsNP, and highest in CRSwNP. in vitro stimulation with TNF-α and IL-4, but not IFN-γ, increased VCAM among CRSsNP, while expression in CRSwNP remained elevated with all treatments except IFN-γ. ex vivo ICAM expression was elevated in both CRS subtypes. in vitro stimulation with TNF-α and IFN-γ, but not IL-4, increased ICAM expression in all patients with the largest effects among the CRSsNP subgroup.

CONCLUSION

Sinonasal fibroblast expression of adhesion molecules in sinusitis varies by disease state and is selectively influenced by exposure to inflammatory cytokines.

Effect of new macrolides on the expression of adhesion molecules on neutrophils in chronic sinusitis

To elucidate the mechanisms involved in the action of new macrolides on chronic sinusitis, we examined the effects of clarithromycin (CAM) and roxiythromycin (RXM) on the expression of adhesion molecules (L-selectin and Mac-1) on peripheral blood neutrophils of individuals with chronic sinusitis. The administration of CAM and RXM slightly inhibited the down-regulation of L-selectin expression on neutrophils induced by interleukin (IL)-8 stimulation. Furthermore, the administration of CAM strongly inhibited the IL-8-induced up-regulation of Mac-1 expression on neutrophils. These observations suggest that the new macrolides such as CAM and RXM may affect the functions of neutrophils in chronic sinusitis by modulating the expression of L-selectin and Mac-1 molecules on neutrophils, thereby attenuating the adhesion of neutrophils.

How does endotoxin trigger inflammation in otitis media with effusion?

OBJECTIVES

The relationship among microorganisms, endotoxin, and inflammatory mediators in otitis media with effusion (OME) was examined.

STUDY DESIGN

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.

Assembly of multimeric von Willebrand factor directs sorting of P-selectin

We designed a model system to study the role of von Willebrand factor (vWF) in the sorting of P-selectin and the biogenesis of Weibel-Palade body (WPB)-like organelles. For that purpose, a human epithelial cell line (T24) that synthesizes P-selectin mRNA, but which is devoid of vWF mRNA synthesis and storage organelles, was transfected with full-length vWF cDNA or a deletion mutant thereof. Stable transfectants of T24 with full-length vWF cDNA revealed the generation of WPB-like organelles as demonstrated by colocalization of vWF and P-selectin with double-labeling immunofluorescence. In contrast, T24 cells transfected with vWF delD'D3 cDNA, encoding a mutant that is unable to form vWF multimers, displayed only perinuclear vWF staining, whereas no indication was found for the presence of WPB-like organelles. The contents of the organelles in full-length vWF cDNA-transfected T24 cells were released on activation of the protein kinase C pathway, similar to the situation with genuine endothelial cells. The expression of vWF did not affect the biosynthesis of P-selectin, as deduced from the observation that untransfected and vWF cDNA-transfected T24 cells contained the same amount of P-selectin mRNA. We propose that the biosynthesis of multimeric vWF directs the generation of WPB-like organelles, as evidenced by the sequestering and anchoring of P-selectin into these storage granules.