Reduced levels of lactoferrin in biofilm-associated chronic rhinosinusitis

Current evidence of biofilms in chronic rhinosinusitis- a microbiological perspective

INTRODUCTION

Chronic rhinosinusitis (CRS) is characterized by inflammation of the paranasal sinus mucosa persisting for more than 12 weeks. This condition is associated with reduced quality-of-life and causes a high direct and indirect economic burden. Several pathogenic factors have been attributed to CRS, including bacterial and fungal biofilms on the sinonasal mucosa. Biofilms are well-established contributors to recalcitrance to treatment in other chronic inflammatory mucosal conditions such as cystic fibrosis and otitis media.

AREAS COVERED

This review will present an overview of the role of biofilms in CRS, including the evidence for biofilms being present on the sinonasal mucosa and their implications for disease severity. Furthermore, the interactions between biofilms and host-mediated immune factors are explored.

EXPERT OPINION

The eradication of biofilms has been a focus of research shortly after their recognition as a cause of disease. The currently available methodologies for identifying biofilms on mucosal surfaces are not sufficiently well-developed to be used in a clinical setting. A more accurate, cheaper, faster approach for biofilm detection is necessary, and molecular techniques may provide the possibility for this.

The mechanisms of biofilm antibiotic resistance in chronic rhinosinusitis: A review

Chronic rhinosinusitis (CRS) is a common but burdensome ailment that is still poorly understood in terms of its pathogenesis. The existence of biofilms on the sinonasal mucosa of individuals with CRS has been proven by current biofilm identification methods. Current treatments for CRS generally include functional endoscopic sinus surgery, biofilm-removing strategies, and limited therapies that target quorum sensing (QS), patients with CRS are often resistant to antimicrobial therapy at degrees achievable by oral or intravenous administration, and even a subset of patients fail to react to either medical or surgical intervention. Multidrug-resistant Pseudomonas aeruginosa, Staphylococcus aureus, especially methicillin-resistant S. aureus, Streptococcus pneumoniae, and Haemophilus influenzae are the most commonly implicated bacteria in CRS patients, which may lead to the persistence and severity of CRS and antibiotic treatment failure via the formation of biofilms. Resistance to antibiotics is attributed to the 3-dimensional structure and QS of biofilms, and the latter describes the communication of bacteria within biofilms. A better understanding of biofilms in CRS and their contribution to the antibiotic resistance of CRS is critical for novel treatment strategies. This review mainly discusses the special structure of biofilms, QS, and their mechanisms of antibiotic resistance in order to investigate prospective anti-biofilm therapies, suggest future directions for study, and potentially refine the CRS prevention paradigm.

Topical Antibiofilm Agents With Potential Utility in the Treatment of Chronic Rhinosinusitis: A Narrative Review

The role of bacterial biofilms in chronic and recalcitrant diseases is widely appreciated, and the treatment of biofilm infection is an increasingly important area of research. Chronic rhinosinusitis (CRS) is a complex disease associated with sinonasal dysbiosis and the presence of bacterial biofilms. While most biofilm-related diseases are associated with highly persistent but relatively less severe inflammation, the presence of biofilms in CRS is associated with greater severity of inflammation and recalcitrance despite appropriate treatment. Oral antibiotics are commonly used to treat CRS but they are often ineffective, due to poor penetration of the sinonasal mucosa and the inherently antibiotic resistant nature of bacteria in biofilms. Topical non-antibiotic antibiofilm agents may prove more effective, but few such agents are available for sinonasal application. We review compounds with antibiofilm activity that may be useful for treating biofilm-associated CRS, including halogen-based compounds, quaternary ammonium compounds and derivatives, biguanides, antimicrobial peptides, chelating agents and natural products. These include preparations that are currently available and those still in development. For each compound, antibiofilm efficacy, mechanism of action, and toxicity as it relates to sinonasal application are summarised. We highlight the antibiofilm agents that we believe hold the greatest promise for the treatment of biofilm-associated CRS in order to inform future research on the management of this difficult condition.

Expression of Iron-Regulatory Hormone Hepcidin and Iron Transporters Ferroportin and ZIP8 in Patients With and Without Chronic Rhinosinusitis

Airway epithelia express intrinsic antimicrobial and nutrient-sequestering factors, which contribute to the host defense of the respiratory tract. Hepcidin is an endogenous peptide hormone that serves as a key regulator of iron metabolism, and ferroportin and ZIP8 are iron transporters. All exhibit innate antimicrobial activity. The purpose of this pilot study is to determine if molecules involved in iron regulation are expressed within sinus epithelia and to compare levels of expression between patients with and without chronic rhinosinusitis (CRS). Sinus mucosa was obtained from patients with (n = 19) and without (n = 14) CRS. Real-time polymerase chain reaction following RNA extraction was used to quantify expression of hepcidin, ferroportin, and ZIP8 mRNA. Hepcidin, ferroportin, and ZIP8 were all detected in the sinus epithelia of patients with and without CRS. However, only ZIP8 was significantly changed in CRS, with a 2.5-fold mean increase in mRNA expression relative to controls ( P = .005). These findings suggest that ZIP8 may play a role in the innate epithelial defense of the paranasal sinuses.

Modern Conceptions about the Mechanisms of Interaction Between Biofilm and Cellular Immunity Factors

Features of the cellular immune response in the presence of a microbial biofilm are well described in the literature. Based on numerous studies, it became possible to establish a number of patterns: mature biofilms are better protected from immune factors, the effectiveness of antibiofilm strategies depends on species of the microorganisms, forming the biofilm, and, accordingly, on the composition of the biopolymer matrix. For example, rhamnolipids and alginate of Pseudomonas aeruginosa exert a significant negative effect on the function of immunocompetent cells. The bacteria of biofilms became able to turn to their advantage many of the protective reactions developed by the immune system and fixed evolutionarily, applying them for the growth and development of the microbial consortium.

Modern Conceptions about the Mechanisms of Interaction Between Biofilm and Cellular Immunity Factors

Features of the cellular immune response in the presence of a microbial biofilm are well described in the literature. Based on numerous studies, it became possible to establish a number of patterns: mature biofilms are better protected from immune factors, the effectiveness of antibiofilm strategies depends on species of the microorganisms, forming the biofilm, and, accordingly, on the composition of the biopolymer matrix. For example, rhamnolipids and alginate of Pseudomonas aeruginosa exert a significant negative effect on the function of immunocompetent cells. The bacteria of biofilms became able to turn to their advantage many of the protective reactions developed by the immune system and fixed evolutionarily, applying them for the growth and development of the microbial consortium.

Antibodies against the DNABII protein integration host factor (IHF) inhibit sinus implant biofilms

OBJECTIVES

Chronic rhinosinusitis is a common, costly condition often treated with endoscopic sinus surgery and intraoperative placement of intranasal sinus implant materials. Whereas these materials aid in postoperative healing, they also support bacterial biofilm formation and thus contribute to negative outcomes. This study examined pretreatment of sinus implant materials with antibody against an essential bacterial biofilm structural component, the DNABII family of DNA-binding proteins, as a strategy to prevent biofilm formation.

METHODS

Sinus implant materials were equilibrated in immunoglobulin G (IgG)-enriched antiserum against the DNABII protein integration host factor (IHF), individually or in combination with amoxicillin-clavulanate prior to inoculation with nontypeable Haemophilus influenzae (NTHI), a predominant pathogen of chronic rhinosinusitis. After 16 hours, the bacterial burden was quantitated and compared to pretreatment with saline, IgG-enriched naive serum, or amoxicillin-clavulanate alone.

RESULTS

NTHI readily formed biofilms on all three materials in vitro. However, pretreatment of each material with IgG-enriched anti-IHF resulted in a significant decrease in bacterial burden compared to controls (P ≤ 0.05). Moreover, a significant and synergistic outcome was achieved with a cocktail of anti-IHF plus amoxicillin-clavulanate (P ≤ 0.05) with complete inhibition of NTHI biofilm formation on all three materials.

CONCLUSIONS

Biofilm formation was well supported in vitro on three sinus implant materials that vary in composition and resorption characteristics; however, pretreatment of each with DNABII protein targeted antibodies in combination with a previously ineffective antibiotic was highly effective to prevent the formation NTHI biofilms. These data demonstrate the potential for clinical utility of pretreatment of sinus implant and additional surgical materials with anti-DNABII antibodies.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:1364-1371, 2020.

Biofilm Formations in Pediatric Respiratory Tract Infection : Part 1: Biofilm Structure, Role of Innate Immunity in Protection Against and Response to Biofilm, Methods of Biofilm Detection, Pediatric Respiratory Tract Diseases Associated with Mucosal Biofilm Formation

PURPOSE OF REVIEW

Biofilm represents an organized structure of microorganisms within an extracellular matrix attached to a surface. While the importance of biofilm in prosthetic heart valve and catheter-related infections has been known since the 1980s, the role of mucosal biofilm in human disease pathogenesis has only recently been elucidated. It is now clear that mucosal biofilm is present in both healthy and pathologic states. The purpose of this review is to examine the role of mucosal biofilm in pediatric respiratory infections.

RECENT FINDINGS

Mucosal biofilm has been implicated in relationship to several pediatric respiratory infections, including tonsillitis, adenoiditis, otitis media with effusion, chronic rhinosinusitis, persistent endobronchial infection, and bronchiectasis. In these conditions, core pathogens are detected in the biofilm, biofilm organisms are often detected by molecular techniques when conventional cultures are negative, and biofilm presence is more extensive in relation to disease than in healthy tissues. In chronic rhinosinusitis, the presence of polymicrobial biofilm is also a predictor of poorer outcome following sinus surgery. Biofilm in the tonsillar and adenoidal compartments plays a distinct role in contributing to disease in the middle ear and sinuses. Key observations regarding the relevance of biofilm to pediatric respiratory infections include (1) the association between the presence of biofilm and persistent/recurrent and more severe disease in these tissues despite antibiotic treatment, (2) linkage between biofilm core pathogens and acute infections, and (3) interrelationship between biofilm presence in one tissue and persistent or recurrent infection in an adjacent tissue. A greater understanding of the significance of mucosal biofilm will undoubtedly emerge with the development of effective means of eradicating mucosal biofilm.

l-Methionine anti-biofilm activity against Pseudomonas aeruginosa is enhanced by the cystic fibrosis transmembrane conductance regulator potentiator, ivacaftor

BACKGROUND

Biofilms may contribute to refractory chronic rhinosinusitis (CRS), as they lead to antibiotic resistance and failure of effective clinical treatment. l-Methionine is an amino acid with reported biofilm-inhibiting properties. Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator with mild antimicrobial activity via inhibition of bacterial DNA gyrase and topoisomerase IV. The objective of this study was to evaluate whether co-treatment with ivacaftor and l-methionine can reduce the formation of Pseudomonas aeruginosa biofilms.

METHODS

P aeruginosa (PAO-1 strain) biofilms were studied in the presence of l-methionine and/or ivacaftor. For static biofilm assays, PAO-1 was cultured in a 48-well plate for 72 hours with stepwise combinations of these agents. Relative biofilm inhibitions were measured according to optical density of crystal violet stain at 590 nm. Live/dead assays (BacTiter-Glo™ assay, Promega) were imaged with laser scanning confocal microscopy. An agar diffusion test was used to confirm antibacterial effects of the drugs.

RESULTS

l-Methionine (0.5 μM) significantly reduced PAO-1 biofilm mass (32.4 ± 18.0%; n = 4; p < 0.001) compared with controls. Low doses of ivacaftor alone (4, 8, and 12 μg/mL) had no effect on biofilm formation. When combined with ivacaftor (4 μg/mL), a synergistic anti-biofilm effect was noted at 0.05 μM and 0.5 μM of l-methionine (two-way analysis of variane, p = 0.0415) compared with corresponding concentrations of l-methionine alone.

CONCLUSION

Ivacaftor enhanced the anti-biofilm activity of l-methionine against the PAO-1 strain of P aeruginosa. Further studies evaluating the efficacy of ivacaftor/l-methionine combinations for P aeruginosa sinusitis are planned.

Biofilm and Osteitis in Refractory Chronic Rhinosinusitis

Our understanding of chronic rhinosinusitis (CRS) show biofilm and osteitis play a role in the disease's pathogenesis and refractory. Studies point to its role in pathogenesis and poor prognosis. Outside the research laboratory, biofilm detection remains difficult and specific treatment remains elusive. It is believed that osteitis is a nidus of inflammation and occurs more commonly in patients with refractory CRS. However, osteitis may be exacerbated by surgery and a marker of refractory disease, not a causative agent. Surgery remains the mainstay treatment for biofilm and osteitis with mechanical disruption and removal of disease load providing the most effective treatment.

Lactoferrin: Balancing Ups and Downs of Inflammation Due to Microbial Infections

Lactoferrin (Lf) is a glycoprotein of the primary innate immune-defense system of mammals present in milk and other mucosal secretions. This protein of the transferrin family has broad antimicrobial properties by depriving pathogens from iron, or disrupting their plasma membranes through its highly cationic charge. Noteworthy, Lf also exhibits immunomodulatory activities performing up- and down-regulation of innate and adaptive immune cells, contributing to the homeostasis in mucosal surfaces exposed to myriad of microbial agents, such as the gastrointestinal and respiratory tracts. Although the inflammatory process is essential for the control of invasive infectious agents, the development of an exacerbated or chronic inflammation results in tissue damage with life-threatening consequences. In this review, we highlight recent findings in in vitro and in vivo models of the gut, lung, oral cavity, mammary gland, and liver infections that provide experimental evidence supporting the therapeutic role of human and bovine Lf in promoting some parameters of inflammation and protecting against the deleterious effects of bacterial, viral, fungal and protozoan-associated inflammation. Thus, this new knowledge of Lf immunomodulation paves the way to more effective design of treatments that include native or synthetic Lf derivatives, which may be useful to reduce immune-mediated tissue damage in infectious diseases.

Immunopathogenesis of Chronic Rhinosinusitis and Nasal Polyposis

Chronic rhinosinusitis (CRS) is a troublesome, chronic inflammatory disease that affects over 10% of the adult population, causing decreased quality of life, lost productivity, and lost time at work and leading to more than a million surgical interventions annually worldwide. The nose, paranasal sinuses, and associated lymphoid tissues play important roles in homeostasis and immunity, and CRS significantly impairs these normal functions. Pathogenic mechanisms of CRS have recently become the focus of intense investigations worldwide, and significant progress has been made. The two main forms of CRS that have been long recognized, with and without nasal polyps, are each now known to be heterogeneous, based on underlying mechanism, geographical location, and race. Loss of the immune barrier, including increased permeability of mucosal epithelium and reduced production of important antimicrobial substances and responses, is a common feature of many forms of CRS. One form of CRS with polyps found worldwide is driven by the cytokines IL-5 and IL-13 coming from Th2 cells, type 2 innate lymphoid cells, and probably mast cells. Type 2 cytokines activate inflammatory cells that are implicated in the pathogenic mechanism, including mast cells, basophils, and eosinophils. New classes of biological drugs that block the production or action of these cytokines are making important inroads toward new treatment paradigms in polypoid CRS.

Biofilms in chronic rhinosinusitis: Pathophysiology and therapeutic strategies

BACKGROUND

There is increasing evidence that biofilms are critical to the pathophysiology of chronic infections including chronic rhinosinusitis (CRS). Until relatively recently, our understanding of biofilms was limited. Recent advances in methods for biofilm identification and molecular biology have offered new insights into the role of biofilms in CRS. With these insights, investigators have begun to investigate novel therapeutic strategies that may disrupt or eradicate biofilms in CRS.

OBJECTIVE

This review seeks to explore the evidence implicating biofilms in CRS, discuss potential anti-biofilm therapeutic strategies, and suggest future directions for research.

RESULTS

The existing evidence strongly supports the role of biofilms in the pathogenesis of CRS. Several anti-biofilm therapies have been investigated for use in CRS and these are at variable stages of development. Generally, these strategies: 1) neutralize biofilm microbes; 2) disperse existing biofilms; or 3) disrupt quorum sensing. Several of the most promising anti-biofilm therapeutic strategies are reviewed.

CONCLUSIONS

A better understanding of biofilm function and their contribution to the CRS disease process will be pivotal to the development of novel treatments that may augment and, potentially, redefine the CRS treatment paradigm. There is tremendous potential for future research.

Pediatric chronic rhinosinusitis

The goal of this review is to elucidate the pathogenic factors, histopathologic features, and special considerations that relate to pediatric versus adult chronic rhinosinusitis (CRS) and to emphasize differences and similarities between the adult and pediatric conditions. Emphasis is placed on understanding of the differences in pathogenic mechanisms, host-microbial interactions, potential defects in innate antimicrobial immunity, and the role of biofilm formation in pediatric versus adult CRS and how these translate to different approaches toward both medical and surgical management. Pediatric CRS can be viewed as evolving from acute bacterial rhinosinusitis into an uncomplicated "early" stage of CRS, later evolving into a persistent stage and, in some cases, evolving into a late "maladaptive-eosinophilic" stage disease. Given this potential evolution toward more irreversible disease, a plea can be made for improved recognition of and more aggressive early intervention for pediatric CRS, it is hoped, to prevent these long-term consequences. For the primary care physician, this may necessitate enlisting the support of a sinus specialist before the symptoms of CRS have persisted for months or years. It may also necessitate, in some cases, the use of sinus computed tomography imaging to demonstrate that sinus abnormalities have resolved. Other arguments can be made for prompt and comprehensive management of pediatric CRS, including the need to reduce the burden of illness, reduce health care costs, avoid unnecessary antibiotic use and its attendant effects toward promoting antibiotic resistant infections and, potentially, to reduce the development of important comorbidities, e.g., asthma.

New insights into upper airway innate immunity

BACKGROUND

Protecting the upper airway from microbial infection is an important function of the immune system. Proper detection of these pathogens is paramount for sinonasal epithelial cells to be able to prepare a defensive response. Toll-like receptors and, more recently, bitter taste receptors and sweet taste receptors have been implicated as sensors able to detect the presence of these pathogens and certain compounds that they secrete. Activation of these receptors also triggers innate immune responses to prevent or counteract infection, including mucociliary clearance and the production and secretion of antimicrobial compounds (e.g., defensins).

OBJECTIVE

To provide an overview of the current knowledge of the role of innate immunity in the upper airway, the mechanisms by which it is carried out, and its clinical relevance.

METHODS

A literature review of the existing knowledge of the role of innate immunity in the human sinonasal cavity was performed.

RESULTS

Clinical and basic science studies have shown that the physical epithelial cell barrier, mucociliary clearance, and antimicrobial compound secretion play pivotal innate immune roles in defending the sinonasal cavity from infection. Clinical findings have also linked dysfunction of these defense mechanisms with diseases, such as chronic rhinosinusitis and cystic fibrosis. Recent discoveries have elucidated the significance of bitter and sweet taste receptors in modulating immune responses in the upper airway.

CONCLUSION

Numerous innate immune mechanisms seem to work in a concerted fashion to keep the sinonasal cavity free of infection. Understanding sinonasal innate immune function and dysfunction in health and disease has important implications for patients with respiratory ailments, such as chronic rhinosinusitis and cystic fibrosis.

Drivers of chronic rhinosinusitis: Inflammation versus infection

Studies of the underlying cause or causes of chronic rhinosinusitis (CRS) over the past 20 or more years have expanded from a focus on systemic immune and allergic mechanisms to an intense search for the underlying drivers of mucosal inflammation. These drivers involve mucosal inflammatory pathways that become activated by allergens, microbial stimuli, or poorly understood exogenous or endogenous stimuli. The holy grail in the study of CRS is to identify specific drivers of mucosal inflammation and translate these into more effective treatment for CRS. Certain deficiencies in local innate immunity have been described in patients with CRS that predispose to increased sinus mucosal bacterial colonization/infection, including deficient local production of antimicrobial lactoferrin and deficient functioning of the bitter taste receptor TAS2R38. Conversely, certain innate factors, namely IL-25, IL-33, and thymic stromal lymphopoietin (TSLP), are elaborated by sinus epithelial cells in response to microbial stimulation or airway injury and promote local TH2 inflammation. The precise physiologic role of these factors in innate or adaptive immunity is unclear, although IL-33 might function as an alarmin triggered by damage-associated molecular patterns. The cytokines IL-25 and TSLP, similarly promote proinflammatory tissue responses. Another feature of epithelial dysregulation in patients with CRS is overproduction of eosinophil-promoting C-C chemokines by sinus epithelium, perhaps driven in part through innate stimuli, as well as TH2 cytokines, such as IL-13. Strategies to reduce the microbial stimulation of maladaptive TH2 inflammation or to suppress the local elaboration of TH2-promoting epithelial factors, such as IL-33, have potential therapeutic benefit in patients with CRS, although the extent to which this is realized in patient care remains limited at present. This rostrum will summarize my views on the major microbial drivers of mucosal inflammation and dysregulation of innate TH2-promoting factors in patients with CRS based on recent experimental data.

Chronic rhinosinusitis pathogenesis

There are a variety of medical conditions associated with chronic sinonasal inflammation, including chronic rhinosinusitis (CRS) and cystic fibrosis. In particular, CRS can be divided into 2 major subgroups based on whether nasal polyps are present or absent. Unfortunately, clinical treatment strategies for patients with chronic sinonasal inflammation are limited, in part because the underlying mechanisms contributing to disease pathology are heterogeneous and not entirely known. It is hypothesized that alterations in mucociliary clearance, abnormalities in the sinonasal epithelial cell barrier, and tissue remodeling all contribute to the chronic inflammatory and tissue-deforming processes characteristic of CRS. Additionally, the host innate and adaptive immune responses are also significantly activated and might be involved in pathogenesis. Recent advancements in the understanding of CRS pathogenesis are highlighted in this review, with special focus placed on the roles of epithelial cells and the host immune response in patients with cystic fibrosis, CRS without nasal polyps, or CRS with nasal polyps.

Epidemiology of chronic rhinosinusitis, selected risk factors, comorbidities, and economic burden

Chronic rhinosinusitis (CRS) is a relevant and prevalent medical condition in Germany, Europe and the world. If analysed in detail, the prevalence of CRS shows regional and temporary variety. In this review, currently available data regarding the prevalence of CRS is therefore sorted by country and/or region, time point of data collection and the CRS-definition employed. Risk factors like smoking and gastroesophageal reflux are discussed regarding their influence on CRS prevalence. Moreover, comorbidities of CRS, like asthma, conditions of the cardiovascular system and depression are listed and their influence on CRS is discussed. Furthermore, data on CRS prevalence in special cohorts, like immunocompromised patients, are presented. To estimate the economic burden of CRS, current data e.g. from Germany and the USA are included in this review.

Different activations of toll-like receptors and antimicrobial peptides in chronic rhinosinusitis with or without nasal polyposis

Both up- and down-regulation of the Toll-like receptors (TLRs) and antimicrobial peptides (AMPs) of the sinonasal mucosa have already been associated with the pathogenesis of chronic rhinosinusitis with (CRSwNP) or without (CRSsNP) nasal polyps. The objective of this study was to determine the expression of all known TLR and several AMP genes and some selected proteins in association with allergy, asthma and aspirin intolerance (ASA) in CRS subgroups. RT-PCR was applied to measure the mRNA expressions of 10 TLRs, four defensins, lysozyme, cathelicidin and lactoferrin (LTF) in sinonasal samples from patients with CRSsNP (n = 19), CRSwNP [ASA(-): 17; ASA(+): 7] and in control subjects (n = 12). Protein expressions were detected with immunohistochemistry (n = 10). Statistical analysis was done with the Kruskal-Wallis ANOVA, Mann-Whitney U, and Student t test. TLR2, TLR5, TLR6, TLR7, TLR8, TLR9, β-defensins 1 and 4, cathelicidin and LTF mRNA expressions were significantly (p < 0.05) increased in CRSwNP, whereas only TLR2 and LTF were up-regulated in CRSsNP compared to controls. There was no statistical difference in respect of allergy, aspirin intolerance and smoking between CRSsNP, ASA(-) and ASA(+) CRSwNP patients. TLR2, TLR3, TLR4, LTF, β defensin 2 and lysozyme protein expressions were found to be elevated in macrophages of CRSwNP samples (p < 0.05). Gene expression analysis showed markedly different expressions in CRSwNP (6 out of 10 TLR and 4 out of 7 AMP genes were up-regulated) compared to CRSsNP (1/10, 1/7). The distinct activation of the innate immunity may support the concept that CRSsNP and CRSwNP are different subtypes of CRS. These findings were found to be independent from allergy, asthma, smoking, aspirin intolerance and systemic steroid application.

Novel microbiome-based therapeutics for chronic rhinosinusitis

The human microbiome, i.e. the collection of microbes that live on, in and interact with the human body, is extraordinarily diverse; microbiota have been detected in every tissue of the human body interrogated to date. Resident microbiota interact extensively with immune cells and epithelia at mucosal surfaces including the airways, and chronic inflammatory and allergic respiratory disorders are associated with dysbiosis of the airway microbiome. Chronic rhinosinusitis (CRS) is a heterogeneous disease with a large socioeconomic impact, and recent studies have shown that sinus inflammation is associated with decreased sinus bacterial diversity and the concomitant enrichment of specific sinus pathogens. Here, we discuss the potential role for probiotic supplementation for CRS in light of this increasing understanding of the airway microbiome and microbial interactions with the host. We focus on the ecological significance of microbiome-based probiotic supplementation and potential interactions with the gastrointestinal tract and consider microbial administration methods for treatment of CRS.

Biofilms in chronic rhinosinusitis: what is new and where next?

Background:

Chronic rhinosinusitis is a common, heterogeneous condition. An effective means of mitigating disease in chronic rhinosinusitis patients remains elusive. A variety of causes have been implicated, with the biofilm theory gaining increasing prominence.

Objective:

This article reviews the literature on the role of biofilms in chronic rhinosinusitis, in terms of pathophysiology and with regard to avenues for future treatment.

Methods:

A systematic review of case series was performed using databases with independently developed search strategies, including Medline, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane library, and Zetoc, in addition to conference proceedings and a manual search of literature, with the last search conducted on 18 January 2014. The search terms included the following, used in various combinations to maximise the yield of articles identified: ‘biofilms’, ‘chronic rhinosinusitis’, ‘DNase’, ‘extracellular DNA’ and ‘biofilm dispersal’.

Results:

The existing evidence lends further support for the role of biofilms (particularly the Staphylococcus aureus phenotype) in more severe, recalcitrant disease and poorer surgical outcomes.

Conclusion:

Multimodality treatment, with a shift in paradigm to incorporate anti-biofilm strategies, is likely to form the mainstay of future recalcitrant chronic rhinosinusitis management.

The effects of topical agents on paranasal sinus mucosa healing: a rabbit study

BACKGROUND

Numerous topical agents have been used intraoperatively to enhance postoperative mucosal healing or reduce scar formation. However, the histological effects of many of these treatments have not been well described. This study investigates the impact of topical mometasone furoate, acitretin, lactoferrin, and Silastic sheet (Medtronic) on sinus mucosal healing in a rabbit model.

METHODS

Forty-eight New Zealand white rabbits underwent defined, localized stripping of a bilateral region of maxillary sinus mucosa. One of 6 treatments was placed in 1 maxillary sinus, and the treatment carrier was applied contralaterally (0.1% mometasone furoate, 0.25% and 0.5% acitretin, lactoferrin, Silastic, and no treatment; n = 8 each group). Rabbits were euthanized after 2 weeks and histological sections were examined with light microscopy.

RESULTS

Treatment with acitretin 0.25% and 0.5% improved cilial recovery by 0.9 ± 0.5 (p = 0.003) and 0.5 ± 0.5 (p < 0.05), respectively. Acitretin 0.25% treatment also significantly reduced collagen in healing mucosa (5.1% ± 4.8%, p = 0.04). Conversely, rabbits treated with mometasone furoate 0.1% were more likely to have reduced cilial and goblet cell recovery. Intergroup comparisons demonstrated a significant improvement in cilial recovery scores with both acitretin doses compared with mometasone furoate (p < 0.05) and less collagen deposition in rabbits treated with placebo gel over Silastic (p < 0.05). Mucosa directly underlying a blood clot had a lower cilia score and impaired epithelial recovery (p < 0.001).

CONCLUSION

Intraoperatively applied agents have the potential to significantly affect wound healing. Acitretin improved cilial recovery and reduced collagen deposition.

Enhanced expressions of lysozyme, SLPI and glycoprotein 340 in biofilm-associated chronic rhinosinusitis

Lysozyme, secretory leukocyte proteinase inhibitor (SLPI) and glycoprotein 340 (gp340) are important effectors of the innate immune system in sinonasal mucosa. Bacterial biofilms (BBF) are highly organized bacterial communities resistant to host defense systems. The aim of this study was to investigate the expression of lysozyme, SLPI and gp340 in sinus mucosa from chronic rhinosinusitis (CRS) patients with different BBF status. In this prospective cohort study, 63 CRS patients undergoing endoscopic sinus surgery and 20 controls were enrolled and their mucosal samples from ethmoid sinus were obtained. Biofilms were examined by confocal scanning laser microscopy (CSLM), and the expressions of lysozyme, SLPI and gp340 in mRNA and protein levels were detected using reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry and Western blot assay, respectively. As a result, 35/63 (55.6%) of the patients were BBF positive in the CRS group and none in controls. Both mRNA and protein levels of lysozyme, SLPI and gp340 in patients with CRS were significantly higher than those in controls. When sub-classified according to BBF status, the CRS patients with BBF revealed the significantly enhanced mRNA and protein levels of lysozyme, SLPI and gp340. In conclusion, our study demonstrates that lysozyme, SLPI and gp340 are constitutively expressed in sinus mucosa and their up-regulated expressions on both the mRNA and protein levels are associated with BBF in CRS patients. These findings may offer an insight into the interaction between BBF and the innate immune system.

Reconstituted human upper airway epithelium as 3-d in vitro model for nasal polyposis

Background

Primary human airway epithelial cells cultured in an air-liquid interface (ALI) develop a well-differentiated epithelium. However, neither characterization of mucociliar differentiation overtime nor the inflammatory function of reconstituted nasal polyp (NP) epithelia have been described.

Objectives

1^st) To develop and characterize the mucociliar differentiation overtime of human epithelial cells of chronic rhinosinusitis with nasal polyps (CRSwNP) in ALI culture system; 2^nd) To corroborate that 3D in vitro model of NP reconstituted epithelium maintains, compared to control nasal mucosa (NM), an inflammatory function.

Methods

Epithelial cells were obtained from 9 NP and 7 control NM, and differentiated in ALI culture for 28 days. Mucociliary differentiation was characterized at different times (0, 7, 14, 21, and 28 days) using ultrastructure analysis by electron microscopy; ΔNp63 (basal stem/progenitor cell), β-tubulin IV (cilia), and MUC5AC (goblet cell) expression by immunocytochemistry; and mucous (MUC5AC, MUC5B) and serous (Lactoferrin) secretion by ELISA. Inflammatory function of ALI cultures (at days 0, 14, and 28) through cytokine (IL-8, IL-1β, IL-6, IL-10, TNF-α, and IL-12p70) and chemokine (RANTES, MIG, MCP-1, IP-10, eotaxin-1, and GM-CSF) production was analysed by CBA (Cytometric Bead Array).

Results

In both NP and control NM ALI cultures, pseudostratified epithelium with ciliated, mucus-secreting, and basal cells were observed by electron microscopy at days 14 and 28. Displaying epithelial cell re-differentation, β-tubulin IV and MUC5AC positive cells increased, while ΔNp63 positive cells decreased overtime. No significant differences were found overtime in MUC5AC, MUC5B, and lactoferrin secretions between both ALI cultures. IL-8 and GM-CSF were significantly increased in NP compared to control NM regenerated epithelia.

Conclusion

Reconstituted epithelia from human NP epithelial cells cultured in ALI system provides a 3D in vitro model that could be useful both for studying the role of epithelium in CRSwNP while developing new therapeutic strategies, including cell therapy, for CRSwNP.

Investigation of anti-infection mechanism of lactoferricin and splunc-1

The innate immune system is the first line in the defense system and prevents the body from further bacteria, virus, or fungal infections. Most of the innate immune system is relevant to mucosa immunity. Lactotransferrin is secreted from the human mammal breast duct epithelial tissue and strengthens infant immunity to defense with regard to outward pathogens. Splunc-1 is also an innate material secreted from the soft palate, lung, nasal cavity epithelium, and mucosa. It helps with mucosa defense against bacterial, virus, and even fungus. LPS is the main etiology of Gram-negative bacilla infection source. And studies of lactoferricin and slpunc-1 both can combine with LPS and subsequently cause insults to the mucosa. Although, we know that both of them partake in an important role in innate immunity, we do not know the effects when they work together. In this study, we just overview silicon stimulation to examine the combination of Lactoferricin and Splunc-1 and the effect with regard to LPS.

Improving patient care via development of a protein-based diagnostic test for microbe-specific detection of chronic rhinosinusitis

OBJECTIVES/HYPOTHESIS

The hypothesis is that signature bacterial proteins can be identified in sinus secretions via high-throughput, proteomic based techniques. Nontypeable Haemophilus influenzae (NTHI) is the most common bacterial pathogen associated with sinusitis and serves as proof of principle pathogen for identifying biomarkers.

STUDY DESIGN

In vitro and in vivo studies using proteomic-based analysis of cultures of NTHI and a novel, experimental chinchilla polymicrobial sinusitis model.

METHODS

Nano-liquid chromatography /tandem mass spectrometry (nano-LC-MS/MS) was performed to annotate the secretome from an NTHI biofilm. A model of NTHI-induced sinusitis was developed in a chinchilla, and NTHI proteins were detected in chinchilla secretions. A reference standard RT-PCR-based assay was adapted to allow for sensitivity and specificity testing of the identified signature biomarkers in human patients.

RESULTS

Outer membrane proteins P2 (OMP-P2) and P5 (OMP-P5) were identified as promising candidates for the detection of NTHI biofilms and positively detected in nasopharyngeal secretions of chinchillas experimentally infected with NTHI. An RT-PCR based test for the presence of NTHI biofilms demonstrated 100% sensitivity and 100% specificity when tested against eight unique strains commonly found in human bacterial rhinosinusitis.

CONCLUSIONS

Proteomic analysis was successful in identifying signature proteins for possible use as a biomarker for chronic rhinosinusitis (CRS). OMP-P2 and OMP-P5 were validated as promising candidates and were positively detected from nasopharyngeal secretions from chinchillas experimentally infected with NTHI. Collectively, these data support the use of OMP-P2 and OMP-P5 as biomarkers for a human clinical trial to develop a point-of-care medical diagnostic test to assist in the diagnosis and treatment of CRS.

Lactoferrin administration into the nostril alleviates murine allergic rhinitis and its mechanisms

Lactoferrin (LF) can downregulate allergic airway inflammation in asthma. However, the in vivo effect of exogenous LF on allergic rhinitis (AR), a disease attributed to airway inflammation, has yet to be determined. We investigated the effect of intranasal administration recombinant human (rh) LF and its underlying mechanisms on AR in BALB/c mice. Multiple parameters of allergic responses were evaluated to determine the effect of rhLF. We found that the number of eosinophils and goblet cells, as well as mRNA and protein expression of type 2 helper T (Th2), Th17 and regulatory T (Treg) cells in the nasal cavity, was significantly upregulated in AR mice compared with the controls, Conversely, administration of rhLF prior to or after intranasal ovalbumin challenge markedly downregulated these same parameters. Th1-specific mRNA and protein expression in the nasal cavity of the controls was not different from that in AR mice, but expression significantly increased with rhLF treatment. The mRNA and protein expression of endogenous LF in the nasal cavity was significantly downregulated in AR mice compared with the controls. However, after rhLF treatment, endogenous LF mRNA and protein expression was significantly upregulated. Exogenous rhLF inhibited allergic inflammation in AR mice, most likely by promoting the endogenous LF expression and skewing T cells to a Th1, but not a Th2 and Th17 phenotype in the nasal mucosa. Our findings suggest that rhLF treatment may be a novel therapeutic approach for prevention and treatment AR.

Host-microbial interactions in patients with chronic rhinosinusitis

There has been considerable investigation of host-microbial interactions in patients with chronic rhinosinusitis (CRS) in hopes of elucidating mechanisms of disease and better treatment. Most attention has been paid to bacterial infection and potential underlying defects in innate immunity. Bacterial biofilm is present in most patients with CRS undergoing surgical intervention, and its presence is associated with more severe disease and worse surgical outcomes. A role for viral or fungal infection in patients with CRS is less clear. There is no evidence for a primary defect in mucociliary clearance in most patients with CRS. Decreased levels of certain antimicrobial proteins, most notably lactoferrin, have been found in sinus secretions, whereas levels of other antimicrobial proteins have been found to be normal. No primary defects in Toll-like receptors have been found in patients with CRS, although a 50% reduced expression of Toll-like receptor 9 was reported in patients with recalcitrant nasal polyps. A polymorphism in a bitter taste receptor was recently associated with refractory CRS and persistent Pseudomonas aeruginosa infection. A downregulation of innate immunity by maladaptive T_H2 tissue inflammation has also been described in patients with recalcitrant nasal polyps, suggesting a link to persistent infection. To date, an effective means of restoring host-microbial balance and mitigating disease in patients with CRS remains elusive.

Role of bacterial and fungal biofilms in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a very common condition that remains poorly understood from a pathogenic standpoint. Recent interest has been sparked by a potential role for biofilms in this process, with a significant body of evidence implicating them in inciting sinonasal inflammation. Biofilms are clearly present on the sinus mucosa of CRS patients, and their presence there is associated with severe disease characteristics and surgical recalcitrance. We are beginning to understand the importance of the species within these biofilms, but there may be other as-yet-unidentified factors at play in influencing disease outcomes. Recent exciting research has emerged documenting the immune response to the presence of biofilms-research that will ultimately solidify the nature and extent of the contribution of biofilms in CRS pathogenesis. Future research should focus on evidence-based antibiofilm treatments with reference to efficacy and timing of treatment.

Host Defence against Bacterial Biofilms: “Mission Impossible”?

Bacteria living as biofilms have been recognised as the ultimate cause of persistent and destructive inflammatory processes. Biofilm formation is a well-organised, genetically-driven process, which is well characterised for numerous bacteria species. In contrast, the host response to bacterial biofilms is less well analysed, and there is the general believe that bacteria in biofilms escape recognition or eradication by the immune defence. In this review the host response to bacterial biofilms is discussed with particular focus on the role of neutrophils because these phagocytic cells are the first to infiltrate areas of bacterial infection, and because neutrophils are equipped with a wide arsenal of bactericidal and toxic entities. I come to the conclusion that bacterial biofilms are not inherently protected against the attack by neutrophils, but that control of biofilm formation is possible depending on a timely and sufficient host response.

Nasal obstruction as a key symptom in allergic rhinitis: efficacy and safety of a medical device in children

BACKGROUND

Allergic rhinitis (AR) is a global health problem that has increased rapidly in prevalence over the past few decades. Nasal congestion, which represents a cardinal symptom of AR, appears to be difficult to treat and, especially for pediatric population, therapies that are both well tolerated and effective in relieving nasal congestion are needed. The aim of the present study was to evaluate the safety and clinical effectiveness of the medical device (lactoferrin, carboximetil β-glucan, D-panthenol, dipotassium glycyrrhizinate) in reducing the allergic rhinitis symptoms.

METHODS

A multicenter prospective study with a pre-post design was performed consecutively enrolling 100 pediatric patients of both genders affected by persistent AR. Patients received 2 puffs into each nostril 2 times a day over the course of 4 weeks. The severity of AR symptoms, as measured by VAS score, was assessed before and after treatment. The main outcomes were improvement in each symptom score and in overall symptom burden (as measured by average symptom scores). Differences in symptoms scores measured before and after treatment were compared using paired-sample Wilcoxon signed rank test. The proportion of participants with adverse effects attributed to the treatment was also computed.

RESULTS

All considered symptoms, including nasal congestion, significantly improve after treatment (p<0.001), while only 9 patients suffered adverse effects (itch, burning sensation, dryness).

CONCLUSION

These results confirm the efficacy and safety of this medical device in pediatric population.

The Effects of Corticosteroid on Tissue Lactoferrin in Patients with Nasal Polyposis

Background

Although, lactoferrin (LF) is the second most important antimicrobial and anti-inflammatory peptide after lysozyme in upper respiratory tract, little is known about its role in chronic rhinosinusitis (CRS). Recent studies pronounced that LF levels were significantly reduced in CRS with nasal polyposis (NP) compared with other subgroups. However, effects of systemic corticosteroid (CS) treatment, which is currently the main NP treatment modality, and subsequent surgical intervention on LF levels are still not known. This study was designed to evaluate the effects of CS treatment and surgical intervention on LF levels in patients with NP.

Methods

Patients with inflammatory NP who were scheduled to undergo CS treatment and a control group were included in this study. LF levels were determined from mucosal samples taken from both groups, before and after CS treatment, and also 1 month after surgical intervention.

Results

Twenty-seven patients with NP and 14 patients who underwent septoplasty were included in the study. Tissue LF levels were significantly lower in the NP group compared with the control group (p = 0.014). Tissue LF levels did not change significantly in NP patients after CS treatment. However, a significant reduction in tissue LF was detected 1 month after endoscopic sinus surgery.

Conclusion

Tissue LF concentrations significantly decreased in patients with NP. CS treatment had no effect on tissue LF levels, whereas postendoscopic sinus surgery, tissue LF levels were getting lower because there was also a reduction in inflammatory load (whether from reduction in mucosa surface area or resolution of disease).

Association of the -33C/G OSF-2 and the 140A/G LF gene polymorphisms with the risk of chronic rhinosinusitis with nasal polyps in a Polish population

Nasal polyps are strongly associated with a risk of chronic rhinosinusitis development as well as other obstruction including asthma and allergy. The following study tested the association of the 140A/G polymorphism of lactoferine (LF) encoding gene and the -33C/G polymorphism of osteoblast-specific factor-2 (OSF-2) encoding gene with a risk of chronic rhinosinusitis with nasal polyps in a Polish population. One hundred ninety five patients of chronic rhinosinusitis with nasal polyps as well as 200 sex, age and ethnicity matched control subjects without chronic sinusitis and nasal polyps were enrolled in this study. Among the group of patients 63 subjects were diagnosed with allergy and 65 subjects with asthma, respectively. DNA was isolated from peripheral blood lymphocytes of patients as well as controls and gene polymorphisms were analyzed by restriction fragments length polymorphism polymerase chain reaction (RFLP-PCR). We reported that the 140A/G LF (OR 4.78; 95% CI 3.07-7.24), the -33C/G OSF-2 OR 3.48; 95% CI 2.19-5.52) and the -33G/G OSF-2 (OR 16.45; 95% CI 6.71-40.30) genotypes were associated with an increased risk of chronic rhinosinusitis with nasal polyps among analyzed group of patients. Moreover, the group of patients without allergy or asthma indicated the association of the -33C/G (OR 3.72; 95% CI 2.24-6.19 and OR 15.11; 95% CI 5.91-38.6) and -33G/G (OR 3.73; 95% CI 2.24-6.19 and OR 14.07; 95% CI 5.47-36.16) genotypes of the OSF-2 as wells as 140A/G (OR 3.89; 95% CI 2.40-6.31 and OR 3.62; 95% CI 2.45-5.34) genotype of OSF-2 with an increased risk of chronic rhinosinusitis with nasal polyps. Finally, it was also found that the selected group of patients with allergy or asthma indicated a very strong association of the -33C/G (OR 2.40; 95% CI 1.23-4.69 and OR 2.40; 95% CI 1.23-4.69, respectively) and -33G/G (OR 16.01; 95% CI 5.77-44.41 and OR 17.90; 95% CI 6.53-49.05, respectively) genotypes of the OSF-2 as wells as 140A/G (OR 3.22; 95% CI 1.74-6.11 and OR 3.25; 95% CI 1.75-6.04, respectively) genotypes with an increased risk of chronic rhinosinusitis with nasal polyps. Thus, our results suggest that LF and OSF-2 gene polymorphisms may have deep impact on the risk of rhinosinusitis nasal polyps' formation which may also depend on asthma or allergy. Our results showed that the 140A/G polymorphism of LF gene and the -33C/G polymorphism of the OSF-2 gene may be associated with the risk of chronic rhinosinusitis with nasal polyps in a Polish population.

Biofilm formation and Toll-like receptor 2, Toll-like receptor 4, and NF-kappaB expression in sinus tissues of patients with chronic rhinosinusitis

BACKGROUND

Bacterial biofilm formation is associated with chronic rhinosinusitis (CRS). However, how bacterial biofilms are related to innate immune response in patients is poorly understood. The aim of this study was to evaluate the prevalence of biofilms in CRS patients and investigate the biofilm-related Toll-like receptor (TLR) and downstream NF-kappaB expression in sinus tissues of patients with CRS.

METHODS

A total of 31 CRS patients and 11 control patients with other diseases undergoing endoscopic sinus surgery were recruited consecutively. Their random sinonasal tissue specimens were examined for the formation of biofilms by scanning electron microscopy. The relative levels of TLR2, TLR4, and NF-kappaB expression in those sinus tissues were determined by quantitative real-time reverse-transcriptase polymerase chain reaction and immunohistochemistry.

RESULTS

Bacterial biofilms were detected in 20 of 31 samples from CRS patients but not in a single sample from control patients. The relative levels of TLR2, TLR4, and NF-kappaB expression in sinus tissues from CRS patients were significantly higher than that of controls, and the relative levels of TLR2 and NF-kappaB, but not TLR4, in biofilm-positive sinus tissues were significantly higher than that in biofilm-negative tissues of those CRS patients.

CONCLUSION

Our data indicated that bacterial biofilms were associated with higher levels of TLR2 and NF-kappaB in the majority of sinus tissues from patients with CRS.

Regulation of virulence gene expression resulting from Streptococcus pneumoniae and nontypeable Haemophilus influenzae interactions in chronic disease

Chronic rhinosinusitis (CRS) is a common inflammatory disease of the sinonasal cavity mediated, in part, by polymicrobial communities of bacteria. Recent molecular studies have confirmed the importance of Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi) in CRS. Here, we hypothesize that interaction between S. pneumoniae and NTHi mixed-species communities cause a change in bacterial virulence gene expression. We examined CRS as a model human disease to validate these polymicrobial interactions. Clinical strains of S. pneumoniae and NTHi were grown in mono- and co-culture in a standard biofilm assay. Reverse transcriptase real-time PCR (RTqPCR) was used to measure gene expression of key virulence factors. To validate these results, we investigated the presence of the bacterial RNA transcripts in excised human tissue from patients with CRS. Consequences of physical or chemical interactions between microbes were also investigated. Transcription of NTHi type IV pili was only expressed in co-culture in vitro, and expression could be detected ex vivo in diseased tissue. S. pneumoniae pyruvate oxidase was up-regulated in co-culture, while pneumolysin and pneumococcal adherence factor A were down-regulated. These results were confirmed in excised human CRS tissue. Gene expression was differentially regulated by physical contact and secreted factors. Overall, these data suggest that interactions between H. influenzae and S. pneumoniae involve physical and chemical mechanisms that influence virulence gene expression of mixed-species biofilm communities present in chronically diseased human tissue. These results extend previous studies of population-level virulence and provide novel insight into the importance of S. pneumoniae and NTHi in CRS.

Adaptive immune responses in Staphylococcus aureus biofilm-associated chronic rhinosinusitis

BACKGROUND

The etiopathogenesis of chronic rhinosinusitis (CRS) is currently an area of intense debate. Recently, biofilms have been proposed as a potential environmental trigger in this disease. In particular, Staphylococcus aureus biofilms appear to be a predictor of severe disease recalcitrant to current treatment paradigms. However, direct causal links between biofilms and host immune activation are currently lacking. This study aimed to document both the adaptive immune responses that characterize S. aureus biofilm-associated CRS and the relative contributions of staphylococcal superantigens and S. aureus biofilms in the inflammatory make-up of this disease.

METHODS

A total of 53 disease subjects and 15 controls were recruited. Sinonasal mucosa was collected for the determination of S. aureus and Haemophilus influenzae biofilms and presence of total and superantigen-specific IgE and for the measurement of cytokines that characterize the T-helper pathways.

RESULTS

Staphylococcus aureus biofilms and superantigens are significantly associated in CRS patients, suggesting the biofilm may be a nidus for superantigen-eluting bacteria. The presence of S. aureus biofilms is associated with eosinophilic inflammation, across the spectrum of CRS, on the back of a T-helper(2) skewing of the host's adaptive immune response (elevated Eosinophilic Cationic Protein and IL-5). This can be distinguished from the superantigenic effect resulting in the induction of IgE.

CONCLUSION

This study provides novel evidence of a link between S. aureus biofilms and skewing of the T-cell response toward the T-helper(2) pathway that is independent of superantigen activities. Further research is required to confirm the cause-effect relationship of this association.

Lactoferrin inhibits the growth of nasal polyp fibroblasts

The aim of this study was to evaluate the effects of lactoferrin (LF) on the growth of fibroblasts derived from nasal polyps. We showed that the proliferation of fibroblasts was inhibited in a dose-dependent manner by both native and recombinant LF. The greatest inhibition of proliferation was caused by human milk-derived, iron-saturated LF. The inhibition of fibroblast proliferation was not species specific because bovine LF also was active. The interaction between LFs and a putative cell receptor did not depend on the sugar composition of the glycan moiety of the LF molecule because lactoferrins of different origins were active and the addition of monosaccharides to the cultures did not block proliferation. However, the treatment of fibroblasts with sodium chlorate (an inhibitor of glycosaminoglycan sulfation) or the addition of heparin abolished the inhibitory effect of LF, suggesting that LF binds heparan sulfate-containing proteoglycans. The significance of LF in nasal excretions in controlling polyp formation is discussed.

Chronic rhinosinusitis with nasal polyps: elevated serum immunoglobulin E is associated with Staphylococcus aureus on culture

BACKGROUND

Recent data has implicated Staphylococcus aureus (SA) superantigen as a potential disease modifier in patients with chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP). The objective of this work was to compare total serum immunoglobulin E (IgE) and serum eosinophils in patients with CRSwNP and CRS without nasal polyps (CRSsNP) based on culture results of the 3 most commonly isolated bacteria.

METHODS

Retrospective review at a tertiary rhinology referral center of patients with CRS over a 4-year period.

RESULTS

Bacterial cultures and immunologic data were obtained from 62 patients with CRSwNP and 34 patients with CRSsNP. SA was the most prevalent bacteria in the CRSwNP group, isolated in 19 patients (31%). Patients with elevated total serum IgE (>114 IU/mL) were more likely to have SA on culture (p = 0.04) in this population. The percent serum eosinophil levels in the SA+ group compared with the SA- group was not significant (6.0 vs 5.1, p = 0.17). Lund-Mackay computed tomography (CT) scores, but not Sino-Nasal Outcome Test 20 (SNOT-20) scores were significantly higher in the SA+ vs SA- group (p = 0.03) in patients with CRSwNP. The CRSsNP group demonstrated no difference in IgE or serum eosinophils between different bacterial groups.

CONCLUSION

Our findings suggest that there is an association between SA sinonasal presence and elevated total serum IgE in patients with CRSwNP. In addition, SA+ patients had higher Lund-Mackay CT scores, indicating a higher objective burden of disease in this group of patients.

Chronic rhinosinusitis as a multifactorial inflammatory disorder

Chronic rhinosinusitis (CRS) is a prevalent health condition characterized by sinonasal mucosal inflammation lasting at least 12 weeks. Heterogeneous in clinical presentation, histopathology, and therapeutic response, CRS represents a spectrum of disease entities with variable pathophysiology. Increased knowledge of cellular and molecular derangements in CRS suggests potential etiologies and targets for therapy. Microbial elements including fungi, staphylococcal enterotoxin, and biofilms have been implicated as inflammatory stimuli, along with airborne irritants and allergens. Defects in innate immunity have gained increased attention as contributors to the chronic inflammatory state. A combination of host susceptibility and environmental exposure is widely believed to underlie CRS, although direct evidence is lacking. Presently, without precise disease definitions and identifiable universal triggers, CRS pathogenesis is broadly described as multifactorial. Current research is beginning to unravel complex and diverse effects of chronic inflammation on sinonasal mucosal homeostasis, but dysfunctional pathways of inflammatory regulation and resolution require further elucidation.

Do biofilms contribute to the initiation and recalcitrance of chronic rhinosinusitis?

Chronic rhinosinusitis is a common disease whose underlying aetiopathogenesis has not been completely understood. Amongst a range of other potential environmental triggers in this disease, a role has recently been proposed for bacterial biofilms. Adopting the biofilm paradigm to explain the initiation and maintenance of this disease may help to clarify previous inconsistencies in this disease that have resulted in the role of bacteria being questioned. Of particular interest is the association of bacterial biofilms with recalcitrant disease states. Over the last five years, research has progressed rapidly since biofilms were first identified on the surface of diseased sinonasal mucosa. Their presence there has now been associated with more severe disease that is often recalcitrant to current management paradigms. Technological advances are allowing accurate characterization of the bacterial and fungal species within these biofilms, which would appear to be an important step in improving our understanding of how these bacterial communities might interact with the host to cause disease. This is an unanswered, yet highly important, question in this field of research that will undoubtedly be an area of investigation in the near future. As the body of evidence suggesting biofilms may be involved in this disease grows, research interest has switched to the development of antibiofilm therapies. Given the unique properties of bacteria existing in this form, biofilm eradication strategies will need to incorporate novel medical therapies into established surgical practices as we attempt to improve the outcomes of our most difficult patients.

Physiology and pathophysiology of respiratory mucosa of the nose and the paranasal sinuses

In this review, anatomy and physiology of the respiratory mucosa of nose and paranasal sinuses are summarized under the aspect of its clinical significance. Basics of endonasal cleaning including mucociliary clearance and nasal reflexes, as well as defence mechanisms are explained. Physiological wound healing, aspects of endonasal topical medical therapy and typical diagnostic procedures to evaluate the respiratory functions are presented. Finally, the pathophysiologies of different subtypes of non-allergic rhinitis are outlined together with treatment recommendations.

Aberrant mucin glycoprotein patterns of chronic rhinosinusitis patients with bacterial biofilms

BACKGROUND

Increasingly bacterial biofilms have been implicated in chronic rhinosinusitis (CRS), and conventional treatment methods have failed to completely eradicate biofilms. (1) Terminal sialic acids present on sinus mucosal glycoproteins are targets for bacterial adherence and biofilm formation. (2) A subpopulation of CRS patients is more susceptible to biofilm formation due to aberrant terminal sialic residue distribution patterns of glycoproteins on their mucosa. (3) The higher levels of sialyl transferase (ST)6Gal1 gene expression contribute to the overall aberrant glycosylation patterns on the host mucosa that predispose this patient cohort to developing biofilms. (4) Mucin glycoprotein MUC7 that has known bactericidal activity displays an overall reduced terminal sugar profile in biofilm positive CRS patients.

METHODS

Confocal scanning laser microscopy, glycoarray analysis, real-time polymerase chain reaction of ST6Gal1, neuraminidase assays and multivariate analysis were used to compare production of sialic acid-degrading enzymes in sinus biopsies from biofilm positive and negative CRS patients with mucosa from healthy controls.

RESULTS

Biofilm-positive CRS patients expressed aberrant glycoprotein patterns with terminal sialics of between 70 and 90 kD (stress value = 0.1414). The ST6Gal1 gene was upregulated, and bacteria isolated from these patients exhibit significantly higher neuraminidase activity (p = 0.0343). We detected a significant lack in the overall expression of terminal sugar residues of MUC7 (stress value = 0.088).

CONCLUSIONS

We observed a strong positive correlation between the aberrant terminal sugar patterns in this sub group of CRS patients with biofilms. The innate immunity function of their MUC7 glycoprotein against bacterial invasion may be compromised in CRS patients.

Combined treatment of Pseudomonas aeruginosa biofilm with lactoferrin and xylitol inhibits the ability of bacteria to respond to damage resulting from lactoferrin iron chelation

With an ageing and ever more obese population, chronic wounds such as diabetic ulcers, pressure ulcers and venous leg ulcers are an increasingly relevant medical concern. Identification of bacterial biofilm contamination as a major contributor to non-healing wounds demands biofilm-targeted strategies to manage chronic wounds. Pseudomonas aeruginosa has been identified as a principal biofilm-forming opportunistic pathogen in chronic wounds. The innate immune molecule lactoferrin and the rare sugar alcohol xylitol have been demonstrated to be co-operatively efficacious against P. aeruginosa biofilms in vitro. Data presented here propose a model for the molecular mechanism behind this co-operative antimicrobial effect. Lactoferrin iron chelation was identified as the primary means by which lactoferrin destabilises the bacterial membrane. By microarray analysis, 183 differentially expressed genes of ≥ 1.5-fold difference were detected. Interestingly, differentially expressed transcripts included the operon encoding components of the pyochelin biosynthesis pathway. Furthermore, siderophore detection verified that xylitol is the component of this novel synergistic treatment that inhibits the ability of the bacteria to produce siderophores under conditions of iron restriction. The findings presented here demonstrate that whilst lactoferrin treatment of P. aeruginosa biofilms results in destabilisation of the bacterial cell membrane though iron chelation, combined treatment with lactoferrin and xylitol inhibits the ability of P. aeruginosa biofilms to respond to environmental iron restriction.

Biofilms in chronic rhinosinusitis: systematic review and suggestions for future research

BACKGROUND

A biofilm is a community of micro-organisms encased within a self-produced, extracellular, polymeric substance. The role of biofilms as a major pathological aetiology in chronic rhinosinusitis would help explain the clinical manifestation of the disease.

OBJECTIVES

To examine the current evidence, and to discuss possible future research directions, in relation to biofilms and chronic rhinosinusitis.

STUDY DESIGN

Systematic literature review.

EVALUATION METHOD

Two assessors independently undertook critical appraisal of the studies identified by the literature search. Significant findings were incorporated into this review. The primary outcome assessed was the presence of biofilm in human mucosal biopsy samples taken from patients with chronic rhinosinusitis, and from healthy controls.

RESULTS

We identified 11 studies examining biofilm formation in human mucosal biopsy samples taken from patients with chronic rhinosinusitis.

CONCLUSION

It is unlikely that biofilms occur in every case of chronic rhinosinusitis; consequently, the significance of 'biofilm detection' in some series should be considered carefully. Several authors have argued strongly for the use of confocal scanning laser microscopy with fluorescent in situ hybridisation probes as the 'gold standard' for biofilm imaging. This imaging modality should be combined with further investigation of the microbiology of chronic rhinosinusitis, and of the efficacy of traditional culture techniques used for pathogen identification.

The impact of biofilms on outcomes after endoscopic sinus surgery

BACKGROUND

Although biofilms have been implicated in the pathogenesis of chronic rhinosinusitis (CRS), there is little evidence that their presence or absence has any effect on the outcomes of endoscopic sinus surgery (ESS). The aim of this study was to investigate the effect of biofilms on postsurgical outcomes after ESS.

METHODS

A prospective, blinded study of 51 consecutive patients undergoing ESS for CRS was conducted. Preoperatively, patients assessed their symptoms using internationally accepted standardized symptom scoring systems and quality-of-life (QOL) measures, i.e., the 10-point Visual Analog Scale (VAS), Sino-Nasal-Outcome-Test 20, and global severity of CRS. Their sinonasal mucosa was graded using the Lund-Kennedy scale and the extent of radiological disease on computed tomography scans was scored using the Lund-McKay scale. Random sinonasal tissue samples were assessed for biofilm presence using confocal laser microscopy. At each postoperative visit, patients reassessed their sinus symptoms and completed QOL measures. Postsurgical state of their sinonasal mucosa was graded endoscopically.

RESULTS

Bacterial biofilms were found in 36 of 51 (71%) CRS patients. Patients with biofilms presented with significantly worse preoperative radiology and nasendoscopy scores (p = 0.003 and 0.01, respectively). After a median follow-up period of 16 months postsurgery, biofilm-positive patients had statistically worse sinus symptoms (VAS, p = 0.002) and worse nasendoscopy scores (p = 0.026). They also required extra postoperative visits and multiple antibiotic treatments deviating from the standard postoperative care required by biofilm-negative patients.

CONCLUSION

This study has shown that patients with biofilms have more severe disease preoperatively and persistence of postoperative symptoms, ongoing mucosal inflammation, and infections. This study strengthens the evidence for the role that biofilms may play in recalcitrant CRS.

Innate immunity

Innate immunity is an exciting area of research in rhinology because emerging evidence suggests that abnormal local immune responses, rather than pathogen-specific adaptive immunity, may play a more important role in the pathogenesis of chronic rhinosinusitis (CRS). This article reviews important recent research regarding the innate immune system and CRS, with particular focus on the role of pattern recognition receptors, antimicrobial peptides and biofilms, epithelial ciliary function, cystic fibrosis, and cigarette smoking, and on areas for future research and therapy.

Anti-biofilm strategies and the need for innovations in wound care

With an aging and obese population, chronic wounds such as diabetic ulcers, pressure ulcers, and venous leg ulcers are of an increasingly relevant medical concern in the developed world. Identification of bacterial biofilm contamination as a major contributor to non-healing wounds demands biofilm-targeted strategies to treat chronic wounds. While the current standard of care has proven marginally effective, there are components of standard care that should remain part of the wound treatment regime including systemic and topical antibiotics, antiseptics, and physical debridement of biofilm and devitalized tissue. Emerging anti-biofilm strategies include novel, non-invasive means of physical debridement, chemical agent strategies, and biological agent strategies. While aging and obesity will continue to be major burdens to wound care, the emergence of wounds associated with war require investigation and biotechnology development to address biofilm strategies that manage multi-drug resistant bacteria contaminating the chronic wound. The article presents some of the recent patents related to anti-biofilm strategy in wound care.

Fungus: a role in pathophysiology of chronic rhinosinusitis, disease modifier, a treatment target, or no role at all?

Fungal spores, due to their ubiquitous nature, are continuously inhaled and deposited on the airway mucosa. This article focuses on the potential role of fungi in chronic rhinosinusitis (CRS). Five forms of fungal disease affecting the nose and paranasal sinuses have been recognized: (1) acute invasive fungal rhinosinusitis (including rhinocerebral mucormycosis), (2) chronic invasive fungal rhinosinusitis, (3) granulomatous invasive fungal rhinosinusitis, (4) fungal ball (mycetoma), and (5) noninvasive (allergic) fungal rhinosinusitis. There are several potential deficits in the innate and potentially also acquired immunity of CRS patients that might reduce or change their ability to react to fungi. There are not many arguments to suggest a causative role for fungi in CRS with or without nasal polyps. However, due to the intrinsic or induced change in immunity of CRS patients, fungi might have a disease-modifying role.