Presence of surfactant lamellar bodies in normal and diseased sinus mucosa

Nasal Lavage Fluid as a Biomedical Sample for Verification of Chlorine Exposure

Chlorine is a toxic chemical that has been used as a chemical warfare agent in recent armed conflicts. There is an urgent need for methods to verify alleged uses of chlorine, and phospholipid chlorohydrins (PL-HOCl) derived from the pulmonary surfactant of exposed victims have previously been proposed as biomarkers of chlorine exposure. Here we describe an improved protocol for the chemical analysis of these biomarkers and its applicability to biomedical samples from chlorine-exposed animals. By the use of a polymeric solid phase-supported transesterification of PL-HOCl using ethanolamine, a common biomarker; oleoyl ethanolamide chlorohydrin (OEA-HOCl), was derived from all the diverse oleoyl PL-HOCl that may be formed by chlorine exposure. Compared to native lipid biomarkers, OEA-HOCl represents a larger biomarker pool and is better suited for nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS analysis), generating 3 amol LOD and a reduced sample carry-over. With the improved protocol, significantly elevated levels of OEA-HOCl was identified in broncho-alveolar lavage fluid (BALF) of chlorine exposed rats, 2-48 hours after exposure. The difficulty of BALF sampling from humans limits the methods usefulness as a verification tool of chlorine exposure. Conversely, nasal lavage fluid (NLF) is readily collected without advanced equipment. In NLF from chlorine-exposed rats, PL-HOCl were identified and significantly elevated levels of the OEA-HOCl biomarker was detected 2- 24 hours after exposure. In order to test the potential of NLF as a biomedical sample for verification of human exposure to chlorine, in-vitro chlorination of human NLF samples was performed. All human in-vitro chlorinated NLF samples exhibited elevated OEA-HOCl biomarker levels, following sample derivatization. This data indicates the potential of human NLF as a biomedical sample for the verification of chlorine exposure but further work is required to develop and validate the method for the use on real-world samples.

Innate and Adaptive Mediators in Cystic Fibrosis and Allergic Fungal Rhinosinusitis

Background

Surfactant-associated proteins (SP) A and D are both innate immunity mediators and produced in normal and diseased sinus mucosa. Cystic fibrosis (CF) is associated with Th1 adaptive inflammation whereas allergic fungal rhinosinusitis (AFRS) is associated with Th2 adaptive inflammation. The purpose of this study is to show and quantify the presence of SP A, SP D, tumor necrosis factor (TNF) alpha, (a Th1 marker), and eotaxin (a Th2 marker) in normal and diseased sinus mucosa.

Methods

Intraoperative sinus mucosal biopsy specimens from human volunteers were obtained during endoscopic sinus surgery for CF (n = 4), AFRS (n = 10), and normal controls (CTLs; n = 4). Specimens were evaluated for presence and quantity of SP A, SP D, and TNF-alpha using Western blot with semiquantitative immunoblot analysis. Eotaxin was quantified using ELISA immunoassay. Results were standardized and reported as picograms of mediator per microgram of total protein.

Results

SP A, SP D, and TNF-alpha levels in CF tissue extracts were 2–10 times higher than levels in AFRS tissue (with SP D and TNF-alpha reaching statistical significance) but CF tissue was not significantly higher than CTL tissue. SP A, SP D, and TNF-alpha were not significantly elevated in AFRS. Eotaxin showed elevated levels in CF and AFRS when compared with CTLs (p = 0.03 and 0.003, respectively).

Conclusion

SP D and TNF-alpha are significantly increased in CF compared with AFRS, suggesting activation of both innate immunity and Th1-mediated inflammation and potential correlation between SPs and downstream adaptive immune responses.

Antimicrobial lipids: Emerging effector molecules of innate host defense

The antimicrobial properties of host derived lipids have become increasingly recognized and evidence is mounting that antimicrobial lipids (AMLs), like antimicrobial peptides, are effector molecules of the innate immune system and are regulated by its conserved pathways. This review, with primary focus on the human body, provides some background on the biochemistry of lipids, summarizes their biological functions, expands on their antimicrobial properties and site-specific composition, presents modes of synergism with antimicrobial peptides, and highlights the more recent reports on the regulation of AML production as well as bacterial resistance mechanisms. Based on extant data a concept of innate epithelial defense is proposed where epithelial cells, in response to microbial products and proinflammatory cytokines and through activation of conserved innate signaling pathways, increase their lipid uptake and up-regulate transcription of enzymes involved in lipid biosynthesis, and induce transcription of antimicrobial peptides as well as cytokines and chemokines. The subsequently secreted antimicrobial peptides and lipids then attack and eliminate the invader, assisted by or in synergism with other antimicrobial molecules delivered by other defense cells that have been recruited to the site of infection, in most of the cases. This review invites reconsideration of the interpretation of cholesteryl ester accumulation in macrophage lipid droplets in response to infection as a solely proinflammatory event, and proposes a direct antimicrobial role of lipid droplet- associated cholesteryl esters. Finally, for the interested, but new- to- the-field investigator some starting points for the characterization of AMLs are provided. Before it is possible to utilize AMLs for anti-infectious therapeutic and prophylactic approaches, we need to better understand pathogen responses to these lipids and their role in the pathogenesis of chronic infectious disease.

Surfactant protein a expression in chronic rhinosinusitis and atrophic rhinitis

Introduction Surfactant protein A (SP-A) exhibits antimicrobial properties and interacts with a variety of respiratory tract pathogens.

Objective The objective of this study was to detect the presence of SP-A and measure its alterations in chronic rhinosinusitis (CRS) and primary atrophic rhinitis (PAR) versus healthy controls.

Methods Inferior turbinate and sinus mucosal biopsies were taken from 30 patients with CRS, 30 patients with PAR, and 20 healthy controls. Immunohistochemical staining for SP-A and polymerase chain reaction (PCR) amplification of SP-A messenger RNA were performed on nasal tissue samples.

Results Immunostaining localized SP-A to the mucosa and submucosal glands in CRS specimens but failed to localize it in PAR specimens. Quantitative PCR showed a high, statistically significant increase in the SP-A levels of patients with CRS when compared with controls (p < 0.0001) and also demonstrated a significant reduction of SP-A in patients with PAR compared with controls (p < 0.005).

Conclusion SP-A is significantly increased in CRS and decreased significantly in PAR and appears to be expressed by respiratory epithelial cells and submucosal glandular elements of the sinonasal mucosa. The potential therapeutic applications of surfactant in the enhancement of mucociliary clearance need to be studied.

Pulmonary surfactant in the airway physiology: a direct relaxing effect on the smooth muscle

Beside alveoli, surface active material plays an important role in the airway physiology. In the upper airways it primarily serves in local defense. Lower airway surfactant stabilizes peripheral airways, provides the transport and defense, has barrier and anti-edematous functions, and possesses direct relaxant effect on the smooth muscle. We tested in vitro the effect of two surfactant preparations Curosurf® and Alveofact® on the precontracted smooth muscle of intra- and extra-pulmonary airways. Relaxation was more pronounced for lung tissue strip containing bronchial smooth muscle as the primary site of surfactant effect. The study does not confirm the participation of ATP-dependent potassium channels and cAMP-regulated epithelial chloride channels known as CFTR chloride channels, or nitric oxide involvement in contractile response of smooth muscle to surfactant.By controlling wall thickness and airway diameter, pulmonary surfactant is an important component of airway physiology. Thus, surfactant dysfunction may be included in pathophysiology of asthma, COPD, or other diseases with bronchial obstruction.

Surfactant protein A and D in chronic rhinosinusitis with nasal polyposis and corticosteroid response

BACKGROUND

Corticosteroids are a mainstay of treatment for chronic rhinosinusitis with nasal polyposis (CRSwNP). Data related to the effect of systemic methylprednisolone on surfactant protein (SP) expression in CRSwNP is limited. This study aimed to reveal the consequences of systemic methylprednisolone treatment on levels of SP-A and SP-D, which play a role in innate immunity, in patients with CRSwNP.

METHODS

Twenty-one patients with CRSwNP were included in the study, along with 15 control patients scheduled for dacryocystorhinostomy. A polypoid tissue biopsy was taken under local anesthesia, and 15 CRSwNP patients were scheduled for endoscopic sinus surgery after 3 weeks of oral methylprednisolone. Posttreatment biopsies were performed perioperatively. Pre- and posttreatment endoscopic polyp grades were determined, as were symptom scores regarding nasal obstruction, headache, and nasal discharge using a visual analog scale (VAS). SP-A and SP-D levels were measured using enzyme-linked immunosorbent assay and the results were compared.

RESULTS

All patients reported relief from clinical symptoms through VAS after methylprednisolone treatment. The posttreatment polyp grade was reduced (p < 0.0001). SP-A and SP-D levels did not yield a significant difference between CRSwNP patients and controls (p = 0.25 and p = 0.13, respectively). Statistically significant up-regulation was detected in SP-A and SP-D levels after oral methylprednisolone (p = 0.0002 and p = 0.0004, respectively).

CONCLUSION

In this study, significant up-regulation of SP-A and SP-D was revealed in patients with CRSwNP after systemic steroid treatment. The role of SP-A and SP-D up-regulation in CRSwNP pathogenesis and therapeutic outcomes of corticosteroids have potential importance for the introduction of new therapeutic modalities that are more effective and produce fewer adverse effects.

Treatment-recalcitrant chronic rhinosinusitis with polyps is associated with altered epithelial cell expression of interleukin-33

BACKGROUND

Abnormalities in host mucosal immunity exist in chronic rhinosinusitis with nasal polyps (CRSwNPs), but it is unclear whether this is a cause or an effect of the eosinophilic inflammation and frequent microbial colonization that characterizes the disease. Sinonasal epithelial cells (SNECs) are critical participants in healthy antimicrobial innate immune defense. They also can promote Th2 inflammation with various mediators, including interleukin (IL)-33, which induces T helper cells to produce Th2 cytokines.

METHODS

CRSwNP SNECs were obtained during sinus surgery and stored. Patients were subsequently classified as either treatment responsive or treatment recalcitrant, based on long-term outcomes of medical and surgical therapy. Epithelial cells from these patients were grown in air-liquid interface (ALI) culture and treated with IL-13, as well as the bacteria-associated molecule, CpG. Expression of IL-33 mRNA was determined by real-time polymerase chain reaction.

RESULTS

Recalcitrant CRSwNP epithelial cells had increased baseline expression of IL-33 compared with responsive CRSwNPs, which was further increased by 24-hour exposure to CpG. Treatment-responsive epithelial cells were not induced by CpG to express IL-33. Prolonged treatment with IL-13 during differentiation at the ALI diminished the baseline expression of IL-33 and prevented the subsequent induction of IL-33 by CpG.

CONCLUSION

Mucosal innate immunity likely plays an important role in CRSwNP pathogenesis. A definitive link between infectious triggers and the development of Th2 inflammation has been elusive. We have found constitutive IL-33 expression by SNECs in recalcitrant CRSwNPs, which can be further induced by a bacteria-associated molecular pattern. Dysregulated epithelial cell immune interactions between host and environment may contribute to Th2 inflammation in CRSwNPs.

Lipids including cholesteryl linoleate and cholesteryl arachidonate contribute to the inherent antibacterial activity of human nasal fluid

Mucosal surfaces provide first-line defense against microbial invasion through their complex secretions. The antimicrobial activities of proteins in these secretions have been well delineated, but the contributions of lipids to mucosal defense have not been defined. We found that normal human nasal fluid contains all major lipid classes (in micrograms per milliliter), as well as lipoproteins and apolipoprotein A-I. The predominant less polar lipids were myristic, palmitic, palmitoleic, stearic, oleic, and linoleic acid, cholesterol, and cholesteryl palmitate, cholesteryl linoleate, and cholesteryl arachidonate. Normal human bronchioepithelial cell secretions exhibited a similar lipid composition. Removal of less-polar lipids significantly decreased the inherent antibacterial activity of nasal fluid against Pseudomonas aeruginosa, which was in part restored after replenishing the lipids. Furthermore, lipids extracted from nasal fluid exerted direct antibacterial activity in synergism with the antimicrobial human neutrophil peptide HNP-2 and liposomal formulations of cholesteryl linoleate and cholesteryl arachidonate were active against P. aeruginosa at physiological concentrations as found in nasal fluid and exerted inhibitory activity against other Gram-negative and Gram-positive bacteria. These data suggest that host-derived lipids contribute to mucosal defense. The emerging concept of host-derived antimicrobial lipids unveils novel roads to a better understanding of the immunology of infectious diseases.

Sinonasal surfactant protein A1, A2, and D gene expression in cystic fibrosis: a preliminary report

OBJECTIVE

To measure alterations in SPA1, A2, and D gene expression in various forms of inflammatory chronic rhinosinusitis (CRS).

STUDY DESIGN AND SETTING

Sinus mucosal biopsies were performed in patients with allergic fungal rhinosinusitis (AFS), CRS with nasal polyposis, cystic fibrosis (CF), and controls. SP mRNA was measured with quantitative polymerase chain reaction.

RESULTS

Patients with CF (n = 4) showed significantly increased SPA1 (82-fold), SPA2 (100-fold), and SPD (47-fold) mRNA (P < 0.05) when compared with controls (n = 5). Patients with CRS with nasal polyposis (n = 5) also demonstrated elevated SPA1 (27-fold), SPA2 (13-fold), and SPD (13-fold). Patients with AFS (n = 7) had increased SPA1 (5-fold), SPA2 (9-fold), and SPD (17-fold), but were not statistically significant.

CONCLUSION

SPA1, A2, and D are upregulated in various forms of CRS, but are significantly elevated in cystic fibrosis CRS.

SIGNIFICANCE

Understanding the role of SPs in CRS will help develop novel treatment approaches for sinonasal pathoses.

Surfactant protein B detection and gene expression in chronic rhinosinusitis

INTRODUCTION

Surfactant protein (SP)-B is a hydrophobic protein secreted within pulmonary surfactant that facilitates the adsorption of surface-active lipids to the air-liquid interface of the alveoli and increases alveolar stability. SP-B may also have anti-inflammatory properties. It is implicated in decreasing the pulmonary inflammatory response to bacterial lipopolysaccharide. However, the expression and function of SP-B in the sinonasal cavities has not been elucidated. Our objective was to detect the presence of SP-B, measure alterations in several forms of chronic rhinosinusitis (CRS), and localize cellular protein expression.

MATERIALS/METHODS

Sinus mucosal biopsies were performed in patients with allergic fungal rhinosinusitis (AFRS), nonatopic CRS with nasal polyposis (NP), and cystic fibrosis (CF) and in healthy controls. SP-B mRNA was measured in CRS and control patients using quantitative polymerase chain reaction. Immunoblot analysis and immunolocalization of SP-B were also performed.

RESULTS

CF (n = 4) showed significantly increased levels of SP-B (169-fold) mRNA (P = .004) when compared with controls (n = 5). CRS with NP (n = 5) and AFRS (n = 7) also demonstrated elevated levels of SP- B (14-fold and 4-fold, respectively) when compared with the control group, although these were not statistically significant. Immunoblot analysis confirmed the presence of the translated product, and immunolocalization revealed expression in the epithelium and submucosal glandular elements.

CONCLUSION

This is the first study to detect and characterize SP-B in human sinus mucosa. Furthermore, SP-B is significantly up-regulated in CF CRS.

Innate immunity of the sinonasal cavity and its role in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is one of the most common health problems in the United States. Medical therapy and surgery are successful in treating the majority of patients with sinusitis; however, CRS patients recalcitrant to traditional therapy are increasingly prevalent. Although traditionally this illness could be explained by sinus ostial obstruction and persistent bacterial infection, the rhinologic literature over the years has suggested a significant underlying inflammatory component. Adaptive immune components, including lymphocytes and their associated cytokines, have been the subject of most research in chronic nasal inflammation. A recent appreciation of the importance of the innate immune system is leading to new areas of investigation regarding the pathogenesis of CRS. This review will outline our current knowledge of sinonasal innate immunity, the role of innate immunity in the pathogenesis of CRS, and potential therapeutic targets in the innate immune system.

Surfactant protein A and D in human sinus mucosa: a preliminary report

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 and its role in chronic sinusitis

Although numerous studies have focused on the nature and defensive role of surfactant in the lower airways, relatively little is known about its role in the upper airways. Decreased levels of the main component of surfactant--phospholipids--have been implicated in atrophic rhinitis. The lamellar body arrangement of phospholipids has now been demonstrated in both normal and diseased sinus tissue, resulting in the implication that these structures may play a crucial role in mucociliary clearance against inhaled pathogens, as well as in the regulation of mucous viscosity. Furthermore, they may be secreted from sinonasal ciliated epithelium. Surfactant proteins (SPs) make up a relatively smaller proportion of surfactant, but appear to have an important role in innate immunity. Altered levels of SPs have been observed in a number of respiratory tract diseases. These SPs may prove to play a significant role in chronic sinusitis. Demonstrated expression of SP-A and SP-D in diseased and normal sinus tissue may mean that these SPs are excreted into the airway-lining fluid of the sinuses. Additionally, initial contact and interaction between pathogens and SP-A and SP-D may occur relatively early after inhalation and deposition into the mucus of the respiratory tract. These findings may lead to potential therapeutic options for difficult-to-treat sinus disease in the future.