Surfactant Protein A and D in Human Sinus Mucosa: A Preliminary Report

Abstract

Introduction: Surfactant-associated proteins (SPs) play a crucial role in the innate defense system and serve as the initial step in the immune response to inhaled pathogens. SP-A and SP-D expression and function are altered in a variety of inflammatory and infectious diseases of the lungs, such as asthma, allergies, and cystic fibrosis, but their presence and function in the sinonasal cavity has not been investigated. The objective of this study was to test our hypothesis that SP-A and SP-D are present in the human sinus. Materials and Methods: Sinus mucosal biopsies were performed in 8 patients undergoing endoscopic sinus surgery for chronic rhinosinusitis with nasal polyposis, pituitary tumors, and cerebrospinal fluid leak repairs. Expression of SP mRNA and protein by the sinus mucosa was detected by RT-PCR and immunoblot analysis, respectively. Results: Analyses of mucosal biopsies from these patients revealed the presence of SP-A and SP-D mRNA and protein in all specimens. Conclusion: SP-A and SP-D are expressed in both normal and diseased human sinus tissue. Understanding the role of SPs in diseased and healthy states may elucidate their possible roles in innate immunity in the upper airway and allow us to develop novel treatments for sinonasal pathologies.

Surfactant Protein B Detection and Gene Expression in Chronic Rhinosinusitis

“…The presence of lamellar bodies and SP‐A, ‐B, and ‐D have been described in the porcine eustachian tube, indicating that the apparatus for a surfactant‐like system is present outside the pulmonary system 12 . Recently, several authors of the present study discovered phospholipid surfactant lamellar bodies in human sinus mucosa by transmission electron microscopy using a novel preparation technique, demonstrated up‐regulation of the hydrophilic SP‐A and ‐D in CF CRS, and localized SP‐A and ‐D to the surface epithelium and submucosal gland ducts (b.a.w., et al, unpublished data, 2007) 14–16 . The data presented in the current study are the first to detect, localize, and characterize SP‐B in human sinus mucosa.…”

Non-Pulmonary Immune Functions of Surfactant Proteins A and D

“…Their possible role in immunity in the nasal mucosa has been supported by studies showing that they are differentially expressed in individuals with certain nasal pathologies. In cystic fibrosis, SP-A1, SP-A2 and SP-D mRNA expression is significantly upregulated in the sinus mucosa [60] . Both SP-A and SP-D are more strongly expressed in the submucosal glands of patients with chronic rhinosinusitis (CRS) [59] .…”

Surfactant proteins A and D are related to severity of the disease, pathogenic bacteria and comorbidity in patients with chronic rhinosinusitis with and without nasal polyps

“…Identification of surfactant proteins and their messenger RNA (mRNA) in healthy and diseased sinonasal mucosa [11][12][13] does not fully reflect their occurrence in the nasal cavity. We evaluated SPs in nasal lavage fluid (NALF) by ELISA method used to detect surfactant proteins in bronchoalveolar lavage fluid.…”