Localization of inflammatory mediators in pediatric sinus mucosa.

OBJECTIVES: Microarray analyses of sinus mucosa in pediatric patients with chronic rhinosinusitis (CRS) have recently demonstrated increased messenger RNA expression of the inflammatory chemokines CXCL5 and CXCL13 and of the innate immune mediators β-defensin 1 (DEFB1), serum amyloid A2 (SAA2), and serpin B4. The objectives of this study were to determine whether these gene products were expressed at the protein level in pediatric sinus mucosa and to determine their localization. DESIGN: Immunohistochemical analysis was used to identify protein expression and cellular localization of CXCL5, CXCL13, DEFB1, SAA2, and serpin B4. Coimmunofluorescence staining of inflammatory cells was performed to further evaluate expression of CXCL5 and CXCL13. SETTING: Pediatric tertiary care facility. PATIENTS: Fifteen children with CRS who underwent endoscopic sinus surgery and 8 children who underwent craniofacial or neurosurgical procedures for abnormalities other than sinusitis. MAIN OUTCOME MEASURES: Protein expression and cellular localization of CXCL5, CXCL13, DEFB1, SAA2, and serpin B4 in pediatric sinus mucosa. RESULTS: Ciliated and basal cells in the pseudostratified epithelium stained positively for the 5 mediators examined in both cohorts. Except for serpin B4, goblet cells did not stain for any mediators in either cohort. Glandular cells stained positively for all 5 mediators in both cohorts. Coimmunofluorescence staining of inflammatory cells showed that CXCL13 was expressed in macrophages, T and B cells but not in neutrophils. CXCL5 was detected only in T cells. CONCLUSIONS: CXCL5, CXCL13, DEFB1, SAA2, and serpin B4 were expressed at the protein level in the sinus mucosa of controls and pediatric patients with CRS and exhibited cell-specific localization. These mediators, not typically associated with pediatric CRS, may be involved in the inflammatory response and mucus hypersecretion seen in pediatric CRS

Development of glandular models from human nasal progenitor cells.

Hyperplasia/hypertrophy of submucosal glands contributes to mucus overproduction in chronic diseases of the upper and lower respiratory tracts, especially in adult and pediatric chronic rhinosinusitis. Mechanisms that lead to glandular hyperplasia/hypertrophy are markedly understudied, reflecting a lack of in vitro model systems wherein airway epithelial progenitor cells differentiate into glandular cells. In this study, we developed and compared several in vitro three-dimensional systems using human nasal epithelial basal cells (HNEBCs) cultured by different methods on two types of extracellular matrices. We demonstrate that HNEBCs cultured on Matrigel (Corning, Tewksbury, MA) form glandular acini-like structures, whereas HNEBCs embedded in a collagen type I matrix form a network of tubules. Fibroblast-conditioned medium increases tubule formation in collagen type I. In contrast, HNEBCs cocultured with fibroblasts self-aggregate into organotypic structures with tubules and acini. These observations provide morphological evidence that HNEBCs are pluripotent and retain the capacity to differentiate into structures resembling specific structural components of submucosal glands depending on the extracellular matrices and culture conditions. The resultant models should prove useful in targeting cross-talk between epithelial cells and fibroblasts to decipher molecular mechanisms and specific signals responsible for the development of glandular hyperplasia/hypertrophy, which in turn may lead to new therapeutic strategies for chronic rhinosinusitis and other inflammatory respiratory diseases characterized by glandular hyperplasia/hypertrophy