The cooperation between orf virus and Staphylococcus aureus leads to intractable lesions in skin infection

A large amount of evidence shows that different kinds of microorganisms can jointly cope with environmental pressures including cell hosts. For example, in many cases, it has been found that secondary or mixed infection of animals caused by ORFV (an epitheliophilic Parapoxvirus) and bacteria (such as Staphylococcus aureus or Streptococcus) shows a mutual aid mode that indirectly leads to the deterioration of the disease. However, the lack of research on the co-pathogenic mechanism, including how to hijack and destroy the cell host in the pathological microenvironment, has hindered the in-depth understanding of the pathogenic process and consequences of this complex infection and the development of clinical treatment methods. Here, we summarized the current strategies of trapping cell hosts together, based on the previously defined ORFV-Host (O-H) system. The opportunistic invasion of S. aureus destroyed the delicate dynamic balance of the O-H, thus aggravating tissue damage through bacterial products (mediated by Agr), even causing sepsis or inducing cytokine storms. In fact, the virus products from its adaptive regulatory system (VARS) weaken the immune attacks and block molecular pathways, so that S. aureus can settle there more smoothly, and the toxins can penetrate into local tissues more quickly. This paper focuses on the main challenges faced by cell hosts in dealing with mixed infection, which provides a starting point for us to deal with this disease in the future.

Mucocutaneous alterations and complications in amphetamine abusers: a narrative review

Amphetamines are the second most commonly used illicit drug worldwide. Amphetamine use can result in significant cutaneous morbidity. This review highlights the dermatological manifestations of amphetamine abuse.

The destruction of mucosal barriers, epithelial remodeling, and impaired mucociliary clearance: possible pathogenic mechanisms of Pseudomonas aeruginosa and Staphylococcus aureus in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a pathological condition characterized by persistent inflammation in the upper respiratory tract and paranasal sinuses. The epithelium serves as the first line of defense against potential threats and protects the nasal mucosa. The fundamental mechanical barrier is formed by the cell-cell contact and mucociliary clearance (MCC) systems. The physical-mechanical barrier is comprised of many cellular structures, including adhesion junctions and tight junctions (TJs). To this end, different factors, such as the dysfunction of MCC, destruction of epithelial barriers, and tissue remodeling, are related to the onset and development of CRS. Recently published studies reported the critical role of different microorganisms, such as Staphylococcus aureus and Pseudomonas aeruginosa, in the induction of the mentioned factors. Bacteria could result in diminished ciliary stimulation capacity, and enhance the chance of CRS by reducing basal ciliary beat frequency. Additionally, bacterial exoproteins have been demonstrated to disrupt the epithelial barrier and induce downregulation of transmembrane proteins such as occludin, claudin, and tricellulin. Moreover, bacteria exert an influence on TJ proteins, leading to an increase in the permeability of polarized epithelial cells. Noteworthy, it is evident that the activation of TLR2 by staphylococcal enterotoxin can potentially undermine the structural integrity of TJs and the epithelial barrier through the induction of pro-inflammatory cytokines. The purpose of this article is an attempt to investigate the possible role of the most important microorganisms associated with CRS and their pathogenic mechanisms against mucosal surfaces and epithelial barriers in the paranasal sinuses. Video Abstract.

Enzymatically releasable polyethylene glycol - host defense peptide conjugates with improved activity and biocompatibility

Host defense peptides (HDPs) have been the subject of great interest for the treatment of multidrug-resistant bacterial infections due to their multimodal activity and low induction of resistance. However, aggregation, toxicity, and short biological half-life have limited their applicability for clinical treatment. Many methods have been explored to alleviate these issues, such as polymer (e.g., polyethylene glycol (PEG)) conjugation, but these are often accompanied by reductions in the activity of the HDP. Here, we detail the design of a novel PEG-HDP conjugate incorporating an enzymatic cleavage sequence targeting matrix metalloproteinases (MMPs) that accumulate at sites of inflammation and infection. Addition of the cleavage sequence onto either the N- or the C-terminal region of the parent peptide (peptide 73, a derivative of the HDP aurein 2.2) was explored to determine the location for optimal antimicrobial activity following MMP cleavage; furthermore, the susceptibility of the peptide to MMP cleavage after conjugation to 2 kDa or 5 kDa PEG was examined. The top candidate, L73, utilized an N-terminal cleavage site that was subsequently conjugated to a 2 kDa PEG polymer. Both L73 and the conjugate exhibited no antimicrobial activity in vitro until cleaved by purified MMP, which liberated a peptide fragment with 16- or 63-fold improved activity, respectively, corresponding to a minimum inhibitory concentration (MIC) of 8 μg/mL, comparable to that of peptide 73 (4 μg/mL). Furthermore, PEG conjugation improved the blood compatibility and reduced the aggregation tendency of the HDP in vitro, indicating enhanced biocompatibility. When administered as a single subcutaneous dose (~3.6 mg, or a peptide concentration of 142 mg/kg) in a mouse abscess model of high-density methicillin-resistant Staphylococcus aureus (MRSA) infection, the conjugate displayed strong activity, reducing abscess size and bacterial load by 73.3% and 58-fold, respectively. This activity was completely lost when the cleavage site was rendered resistant to MMPs by the substitution of two d-amino acids, supporting the hypothesis that antimicrobial activity was dependent on cleavage by MMPs, which were shown here to increasingly accumulate at the abscess site up to 18 h post infection. Finally, the conjugate displayed biocompatibility in vivo, with no identifiable toxicity or aggregation.

Defining the Allergic Endotype of Chronic Rhinosinusitis by Structured Histopathology and Clinical Variables

BACKGROUND

Atopy has a strong association with chronic rhinosinusitis (CRS).

OBJECTIVE

To understand whether patients with atopy and CRS can be defined by markers of tissue histopathology, systemic biomarkers, and clinical factors, which may guide their response to new pharmacologic agents.

METHODS

In a retrospective cohort of CRS patients who underwent functional endoscopic sinus surgery, a structured histopathology report consisting of 12 variables, comorbid conditions, preoperative total serum IgE levels, and preoperative modified Lund-Kennedy endoscopic and sinonasal outcome test (SNOT-22) scores were compared between atopic CRS (aCRS) and non-aCRS control patients in a multivariable model.

RESULTS

A total of 380 CRS patients were enrolled, 286 of whom had comorbid atopy (aCRS). Compared with non-aCRS, aCRS patients had significantly higher preoperative total SNOT-22 scores (40.45 ± 22.68 vs 29.70 ± 20.68, P = .015) and symptom-specific SNOT-22 scores in all domains except psychological dysfunction. Relative to non-aCRS, aCRS patients had increased tissue eosinophilia (P < .0001), eosinophil aggregates (P < .0001), Charcot-Leyden crystals (P < .04), fibrosis (P < .02), total serum IgE levels (P < .04), polyploid disease (P < .001), and a prevalence of comorbid asthma (P < .0001) and aspirin exacerbated respiratory disease (AERD) (P < .003). Patients with aCRS demonstrated increased tissue eosinophilia compared with non-aCRS patients even after controlling for polypoid disease, asthma, and AERD.

CONCLUSION

In the context of CRS, atopy appears to be a specific predictor of CRS severity linked to specific histopathologic variables, including enhanced eosinophilic aggregates. Moving forward, allergic status may be a useful way to identify an atopic endotype of CRS patients. Furthermore, after surgery, patients are often maintained on intranasal corticosteroids. In patients whose disease is unresponsive to steroids, we may look to atopic status to identify another management therapy. Atopic CRS patients, irrespective of polyp and asthmatic status, could be optimal candidates for biologic agents such as T-helper cell, eosinophil, and/or IgE-targeted therapies.

Downregulation of miR‑29b‑3p promotes α‑tubulin deacetylation by targeting the interaction of matrix metalloproteinase‑9 with integrin β1 in nasal polyps

Matrix metalloproteinase (MMP)‑9 is a key enzyme responsible for extracellular matrix degradation and contributes to the progressive histological changes observed in lower respiratory tract infections. Integrin β1 and α‑tubulin are potential MMP‑9‑interacting proteins, and microRNA (miR)‑29b‑3p can regulate MMP‑9 expression. MMP‑9 is highly expressed in chronic rhinosinusitis with nasal polyps (CRSwNPs), regardless of its effects on miR‑29b‑3p, integrin β1 and α‑tubulin expression. In the present study, samples from 100 patients with CRSwNPs were examined via reverse transcription‑quantitative PCR to assess the mRNA expression of miR‑29b‑3p, and western blotting was performed to assess the protein expression of MMP‑2, MMP‑9, acetyl‑α‑tubulin, integrin β1 and tissue inhibitor of metalloproteinase 1 (TIMP‑1). A dual‑luciferase reporter assay was used to verify the direct binding of miR‑29b‑3p and MMP‑2/MMP‑9. Co‑immunoprecipitation (Co‑IP) and GST pull‑down assays showed that integrin β1 and α‑tubulin were MMP‑9‑interacting proteins. Cell viability, apoptosis and inflammatory cytokine levels were determined via a Cell Counting Kit‑8 assay, flow cytometry and ELISA, respectively. miR‑29b‑3p expression was found to be positively correlated with MMP‑2 and MMP‑9 expression. Whereas, TIMP‑1 expression was negatively correlated with MMP‑2 and MMP‑9 expression. The dual‑luciferase assay revealed that miR‑29b‑3p targeted the 3' untranslated region of MMP‑2/MMP‑9. The Co‑IP and GST pull‑down assays showed that MMP‑9 could directly bind to integrin β1 and indirectly bind to α‑tubulin. Finally, the overexpression of miR‑29b‑3p decreased the expression of MMP‑9 and increased the levels of acetyl‑α‑tubulin. By contrast, the knockdown of miR‑29b‑3p increased the expression of MMP‑9 and decreased the levels of acetyl‑α‑tubulin. Additionally, MMP‑9 expression was found to be negatively correlated with acetyl‑α‑tubulin expression. Of note, the expression of integrin β1 did not change following the overexpression and knockdown of MMP‑9. Finally, the overexpression of miR‑29b‑3p not only decreased MMP‑9 expression, but also alleviated lipopolysaccharide‑induced inflammation in NP69 cells. The results showed that the downregulation of miR‑29b‑3p promoted α‑tubulin deacetylation by increasing the number of MMP‑9‑integrin β1 complexes in CRSwNPs, thus targeting miR‑29b‑3p/MMP‑9 may be a potential novel strategy for the clinical treatment of CRSwNPs.

Difference in Host Immune response to Methicillin-Resistant and Methicillin Sensitive Staphylococcus aureus (MRSA and MSSA) Endophthalmitis

PURPOSE

The study aimed to understand the differential immune response of methicillin susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains in in vitro models of endophthalmitis.

METHODS

Retinal pigment epithelium (RPE) and microglia cells (CHME-3) were exposed to MRSA and MSSA strains and analyzed for expression of inflammatory mediators by real-time quantitative PCR and validated by ELISA or immunofluorescence assay. Heatmap and STRING analysis was used to assess the differential immune expression.

RESULTS

Both microglia and RPE expressed TLR-2, TLR-1, TLR-6, and TLR -9 after challenge with MRSA and MSSA strains though the expression varied. MRSA-infected cells induced higher expression of IL-1β, IL-8, 1 L-10, IL-6, and GM-CSF, while TNF-α and IFN-ϒ were downregulated in comparison to MSSA-infected cells. We also demonstrate that MRSA infection leads to increased activation of MMP-9 and MMP-2 in RPE cells, while microglia expressed only MMP-9 in MRSA-infected cells.

CONCLUSIONS

MRSA strain can induce an exacerbated immune response in retinal cells. Giving clues for potential targets in immunomodulatory therapies.

Advances in the Knowledge of the Underlying Airway Remodeling Mechanisms in Chronic Rhinosinusitis Based on the Endotypes: A Review

Chronic rhinosinusitis (CRS) is a chronic inflammatory condition of the nasal and paranasal sinus mucosa that affects up to 10% of the population worldwide. CRS is the most representative disease of the upper respiratory tract where airway remodeling occurs, including epithelial damage, thickening of the basement membrane, fibrosis, goblet cell hyperplasia, subepithelial edema, and osteitis. CRS is divided into two phenotypes according to the presence or absence of nasal polyps: CRS with nasal polyp (CRSwNP) and CRS without nasal polyps (CRSsNP). Based on the underlying pathophysiologic mechanism, CRS is also classified as eosinophilic CRS and non-eosinophilic CRS, owing to Type 2 T helper (Th2)-based inflammation and Type 1 T helper (Th1)/Type 17 T helper (Th17) skewed immune response, respectively. Differences in tissue remodeling in CRS are suggested to be based on the clinical phenotype and endotypes; this is because fibrosis is prominent in CRSsNP, whereas edematous changes occur in CRSwNP, especially in the eosinophilic type. This review aims to summarize the latest information on the different mechanisms of airway remodeling in CRS according to distinct endotypes.

Predictive markers of long-term recurrence in chronic rhinosinusitis with nasal polyps

BACKGROUND

In last years, many attempts were made to recognize chronic rhinosinusitis with nasal polyps (CRSwNP) phenotypes focusing on identifying relevant key pathogenic molecules. Polyps recurrence rate ranges from 4% to 60%, so it's clear that not all clinical and immunologic factors associated with recurrence are known.

OBJECTIVE

We investigate the inflammatory profile in patients with long term recurrent and non-recurrent CRSwNPs and if a specific profile is associated with recurrence, comparing eosinophilic, neutrophilic and lymphocytic infiltration, as well as IL-5 and IL-8 expression to long term recurrence rate.

METHODS

This prospective study included 44 adult patients with CRSwNP treated with endoscopic sinus surgery between 2008 and 2010. Long term follow-up data (8-10 years) indicated that among 44 patients, 18 (40.1%) experienced long term recurrence of nasal polyposis needing maximal medical treatment or revision surgery. We realized two groups: one with patients who didn't present long term recurrence (26 patients) and another with patients who presented long term recurrence (18 patients) and in both groups eosinophilic, neutrophilic and lymphocytic infiltration and IL-5 and IL-8 expression were measured.

RESULTS

The parameters that reached statistical significance (p < 0.05) comparing the two groups were eosinophilic infiltration and IL-5 expression, whereas neutrophilic and lymphocytic infiltration, as IL-8 expression didn't show any significant difference. Asthma and aspirin intolerance seemed significantly more frequent in patients with recurrence, while allergy presented not statistically significant difference between two groups.

CONCLUSIONS

We can conclude that high eosinophilic infiltration and high IL-5 expression in CRSwNP correlate with higher rate of long term recurrence, while neutrophilic and lymphocytic infiltration, and IL-8 expression don't correlate with it. These findings provide the opportunity to improve our ability to predict the prognosis of surgical intervention, although it is still needed to explore the optimal predictor of outcome in CRSwNP.

Understanding the Role of Biofilms and Superantigens in Chronic Rhinosinusitis

PURPOSE OF REVIEW

This review explores recent discoveries in our understanding of how biofilms and superantigens contribute to the pathogenesis of chronic rhinosinusitis (CRS). It also examines clinical implications and novel treatment approaches for biofilm associated CRS.

RECENT FINDINGS

While the role of biofilms in CRS has been studied for 14 years, research interest has now turned toward elucidating new methods of biofilm detection, microbial diversity, and novel treatment approaches. Recent studies on biofilm superantigens aim to clarify the immunological mechanisms of upper airway inflammation, particularly the type-2 response seen in nasal polyposis.

SUMMARY

Biofilms are a topic of research interest for their role in the pathogenesis of chronic rhinosinusitis, particularly when they elute superantigens. New studies on this topic focus on the molecular and cellular mechanisms at play.

Combining multiple tools outperforms individual methods in gene set enrichment analyses

Motivation

Gene set enrichment (GSE) analysis allows researchers to efficiently extract biological insight from long lists of differentially expressed genes by interrogating them at a systems level. In recent years, there has been a proliferation of GSE analysis methods and hence it has become increasingly difficult for researchers to select an optimal GSE tool based on their particular dataset. Moreover, the majority of GSE analysis methods do not allow researchers to simultaneously compare gene set level results between multiple experimental conditions.

Results

The ensemble of genes set enrichment analyses (EGSEA) is a method developed for RNA-sequencing data that combines results from twelve algorithms and calculates collective gene set scores to improve the biological relevance of the highest ranked gene sets. EGSEA’s gene set database contains around 25 000 gene sets from sixteen collections. It has multiple visualization capabilities that allow researchers to view gene sets at various levels of granularity. EGSEA has been tested on simulated data and on a number of human and mouse datasets and, based on biologists’ feedback, consistently outperforms the individual tools that have been combined. Our evaluation demonstrates the superiority of the ensemble approach for GSE analysis, and its utility to effectively and efficiently extrapolate biological functions and potential involvement in disease processes from lists of differentially regulated genes.

Availability and Implementation

EGSEA is available as an R package at http://www.bioconductor.org/packages/EGSEA/. The gene sets collections are available in the R package EGSEAdata from http://www.bioconductor.org/packages/EGSEAdata/.

Supplementary information

Supplementary data are available at Bioinformatics online.

Effect of doxycycline on transforming growth factor-beta-1-induced matrix metalloproteinase 2 expression, migration, and collagen contraction in nasal polyp-derived fibroblasts

PURPOSE

It is well known that doxycycline has antibacterial and anti-inflammatory effects. In this study, we aimed to investigate the effects of doxycycline on the transforming growth factor (TGF) beta 1-induced matrix metalloproteinase (MMP) 2 expression, migration, and collagen contraction, and to determine its molecular mechanism on nasal polyp-derived fibroblasts (NPDF).

METHODS

NPDFs were isolated from the nasal polyps of six patients. Doxycycline was used to pretreat TGF-beta-1-induced NPDFs and ex vivo organ cultures of nasal polyps. Cytotoxicity was evaluated by using a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide assay. Smad2/3 is one of the major transcription factors of TGF-beta signaling. The expression levels of MMP2 and Smad2/3 were measured by using Western blotting, reverse transcription-polymerase chain reaction, and immunofluorescence staining. The enzymic activity of MMP2 was analyzed by using gelatin zymography. Fibroblast migration was evaluated by using transwell migration assays. Contractile activity was measured by a collagen gel contraction assay.

RESULTS

The expression level of MMP2 in nasal polyp tissues increased in comparison with inferior turbinate tissues. TGF-beta-1-induced NPDFs were not affected by doxycycline (0-40 μg/mL). The expression levels of MMP2 and activation of Smad2/3 in TGF-beta-1-induced NPDFs and in organ cultures of nasal polyps were significantly downregulated with doxycycline pretreatment. Doxycycline also reduced TGF-beta-1-induced fibroblast migration and collagen contraction in NPDFs.

CONCLUSION

Doxycycline inhibited TGF-beta-1-induced MMP2 expression, migration, and collagen contraction via the Smad2/3 signal pathways in NPDFs.

Reduced Innate Immune Response to a Staphylococcus aureus Small Colony Variant Compared to Its Wild-Type Parent Strain

Background:Staphylococcus aureus (S. aureus) small colony variants (SCVs) can survive within the host intracellular milieu and are associated with chronic relapsing infections. However, it is unknown whether host invasion rates and immune responses differ between SCVs and their wild-type counterparts. This study used a stable S. aureus SCV (WCH-SK2^SCV) developed from a clinical isolate (WCH-SK2^WT) in inflammation-relevant conditions. Intracellular infection rates as well as host immune responses to WCH-SK2^WT and WCH-SK2^SCV infections were investigated. Method: NuLi-1 cells were infected with either WCH-SK2^WT or WCH-SK2^SCV, and the intracellular infection rate was determined over time. mRNA expression of cells infected with each strain intra- and extra-cellularly was analyzed using a microfluidic qPCR array to generate an expression profile of thirty-nine genes involved in the host immune response. Results: No difference was found in the intracellular infection rate between WCH-SK2^WT and WCH-SK2^SCV. Whereas, extracellular infection induced a robust pro-inflammatory response, intracellular infection elicited a modest response. Intracellular WCH-SK2^WT infection induced mRNA expression of TLR2, pro-inflammatory cytokines (IL1B, IL6, and IL12) and tissue remodeling factors (MMP9). In contrast, intracellular WCH-SK2^SCV infection induced up regulation of only TLR2. Conclusions: Whereas, host intracellular infection rates of WCH-SK2^SCV and WCH-SK2^WT were similar, WCH-SK2^SCV intracellular infection induced a less widespread up regulation of pro-inflammatory and tissue remodeling factors in comparison to intracellular WCH-SK2^WT infection. These findings support the current view that SCVs are able to evade host immune detection to allow their own survival.

Methamphetamine Alters the Antimicrobial Efficacy of Phagocytic Cells during Methicillin-Resistant Staphylococcus aureus Skin Infection

Methamphetamine (METH) is a major drug of abuse in the United States and worldwide. Furthermore, Staphylococcus aureus infections and METH use are coemerging public health problems. S. aureus is the single most important bacterial pathogen in infections among injection drug users, with skin and soft tissue infections (SSTI) being extremely common. Notably, the incidence of SSTI, especially in drug users, is difficult to estimate because such infections are often self-treated. Although there is substantial information on the behavioral and cognitive defects caused by METH in drug users, there is a dearth of knowledge regarding its impact on bacterial infections and immunity. Therefore, we hypothesized that METH exacerbates S. aureus skin infection. Using a murine model of METH administration and wound infection, we demonstrated that METH reduces wound healing and facilitates host-mediated collagen degradation by increased expression and production of matrix metalloproteinase-2 (MMP-2). Additionally, we found that METH induces S. aureus biofilm formation and leads to detrimental effects on the functions of human and murine phagocytic cells, enhancing susceptibility to S. aureus infection. Our findings provide empirical evidence of the adverse impact of METH use on the antimicrobial efficacy of the cells that comprise innate immunity, the initial host response to combat microbial infection.

METH is an extremely addictive central nervous system stimulant that is frequently administered by injection. SSTI, common problems among injection drug users, result in serious morbidity for patients and costly hospitalizations for treatment of superficial wounds and incision and drainage of abscesses; however, there has been little etiologic or preventive epidemiological research on this problem. In addition, the evasive nature of injection drug users toward medical care complicates our ability to accurately predict the prevalence of these infections. Hence, this study investigated the impact of METH use on S. aureus skin infection. Our findings demonstrate that this drug of abuse promotes biofilm formation and negatively impacts the wound healing process and innate immune function, exacerbating susceptibility to S. aureus infection. The findings may translate into new knowledge and development of therapeutic and public health strategies to deal with the devastating complications of METH abuse.

Staphylococcus aureus biofilms induce apoptosis and expression of interferon-γ, interleukin-10, and interleukin-17A on human sinonasal explants

BACKGROUND

Staphylococcus aureus is one of the most common bacteria associated with chronic rhinosinusitis (CRS). Although S. aureus biofilms have been correlated with disease severity in CRS, little is known about the initial immune response that biofilms induce in the sinonasal mucosa.

OBJECTIVE

The aim of this study was to evaluate the innate immune response (in terms of cytokines) of nondiseased human sinonasal tissue to S. aureus biofilms.

METHODS

Full-thickness sinonasal explant cultures (n = 7 donors) were challenged with established S. aureus biofilms for 24 hours. The expression profiles of 17 cytokines were measured using multiplex analysis, real-time quantitative reverse transcription polymerase chain reaction, and immunohistochemistry. Differences in expression were evaluated using Student's t-test.

RESULTS

Interleukin (IL)-1β, IL-10, TNF, IL-17A, and interferon (IFN)-γ were up-regulated at the RNA and protein levels in biofilm-treated tissues compared with controls. Elevation of caspase-3 in biofilm-treated samples indicates S. aureus biofilms induce apoptosis on the sinonasal mucosa.

CONCLUSION

S. aureus biofilms induced apoptosis and a predominant proinflammatory immune response on normal sinonasal mucosal explants. This immune response appeared to be triggered by intrinsic bacterial elements but also by components of the biofilm matrix. Live biofilms were present on the mucosa at the end of the challenge, suggesting an inability of the induced immune response to eliminate the S. aureus biofilms.

Surgical treatment for nasal polyposis: predictors of outcome

Nasal polyps recur in approximately one-third of patients after surgical treatment. It would be beneficial to be able to predict the patients in whom we might expect recurrence and to predict the clinical outcome after surgery. The study included 30 patients operated for nasal polyps. Removed polyps were analyzed by immunohistochemical analysis for IL-5, IgE, vascular endothelial growth factor and eosinophilic infiltration. These parameters together with preoperative CT score were used as independent variables, and subjective score improvement after 2 years was used as a dependent variable in multiple linear regression analysis. Furthermore, the patients were divided into two groups: low and high polyp tissue immunoreactivity. The Chi-squared test was used to determine whether polyp immunoreactivity influences polyp recurrence and subjective score. Preoperative CT score had a slightly positive correlation with subjective score after 2 years. High eosinophil infiltration significantly predicted a higher risk for polyp recurrence. High IL-5 positivity was related to greater risk for polyp recurrence than low IL-5 reactivity but not significantly. IgE and VEGF reactivity in polyp specimens did not have any effect on polyp recurrence. High eosinophilic infiltration in polyps can predict worse outcome after surgical treatment of chronic rhinosinusitis with nasal polyposis. IgE and VEGF do not have prognostic significance to polyp recurrence after surgery. The preoperative extent of disease measured by CT score had a slightly positive correlation with worse outcome after surgery.

Cellular comparison of sinus mucosa vs polyp tissue from a single sinus cavity in chronic rhinosinusitis

BACKGROUND

Nasal polyposis is a common development in chronic rhinosinusitis (CRS), and sinus mucosa and polyp tissue have been used interchangeably in studies investigating CRS. However, potential differences may exist between these 2 tissue types, which have not been entirely characterized.

METHODS

A cross-sectional study of CRS with nasal polyposis (CRSwNP) patients undergoing endoscopic sinus surgery was conducted. Sinus mucosal biopsies and corresponding polyp tissue were obtained from the same sinus cavity via flow cytometry, single-cell suspensions identified type 2 innate lymphoid cells (ILC2s), CD4 and CD8 T cells, activated CD4 and CD8 T cells, plasma cells, plasmacytoid dendritic cells (pDCs), regulatory T cells, T follicular helper cells, B cells, and immunoglobulin A (IgA)(+) and IgG(+) B cells. Cells were measured as a percentage of CD45(+) cells. Paired nonparametric comparisons between sinus and polyp tissue were performed.

RESULTS

Ten patients (50% female; age 48 ± 16 years) were recruited. Significantly elevated ILC2 levels were found in polyp tissue compared to sinus mucosa (0.12 [0.07 to 0.23] vs 0.07 [0.04 to 0.16], p = 0.02), as well as plasma cells (2.25 [0.84 to 3.68] vs 1.18 [0.74 to 2.41], p = 0.01); pDCs (0.15 [0.12 to 0.50[ vs 0.04 [0.02 to 0.17], p = 0.03); activated CD8 T cells (29.22 [17.60 to 41.43] vs 16.32 [10.07 to 36.16], p = 0.04) and IgG(+) B cells (6.96 [0.06 to 11.82] vs 1.51 [0.38 to 5.13], p = 0.04). Other cell populations showed no significant differences.

CONCLUSION

Polyps have a similar cellular composition to that of mucosa. Higher levels of ILC2s, plasma cells, pDCs, activated CD8 T cells, and IgG(+) B cells in polyp tissue may be reflective of cell populations driving nasal polyp development. The cellular machinery of CRS is present in polyps and representative of the disease process. This pilot study strongly suggests that a larger study would provide significant insights into the relationship of sinus mucosa to pathogenesis of nasal polyps.

Differential expression of remodeling markers by tissue structure in nasal polyposis

BACKGROUND

Data on the expression and role of matrix metalloproteinases (MMPs) and their tissue inhibitors (tissue inhibitor of metalloproteinases [TIMPs]) in chronic rhinosinusitis with nasal polyps (CRSwNPs) are contradictory, partly because or the use of different techniques of tissue analysis. The aim of this study was to establish a qualitative/semiquantitative method of analysis on the expression of these remodeling markers in different tissue structures and eosinophils in both NPs and nasal mucosa (NM).

METHODS

NP tissues were obtained from patients undergoing endoscopic sinus surgery for severe CRSwNPs (n = 33) and NM tissues from patients undergoing nasal corrective surgery (n = 12). MMPs (MMP-1, MMP-2, MMP-7, and MMP-9) and TIMP type 1 (TIMP-1) expression were evaluated by immunohistochemistry in tissue structures (epithelium, glands, vessels, and extracellular matrix [ECM]) and eosinophils. Tissue eosinophilia was also analyzed in NP tissues.

RESULTS

MMPs and TIMP-1 expression were found in the epithelium, glands, vessels, and ECM (in both NM and NP) and in eosinophils (only in NP). Significant (p < 0.01) findings were observed in NP compared with NM: increase in MMP-1 in ECM; decrease in MMP-2 in glands, vessels, and epithelium; decrease in MMP-7 in all tissue structures; increase in MMP-9 in ECM and decrease in epithelium and glands; and no differences in TIMP-1. NP tissues showed a clear eosinophilic inflammation compared with NM (p < 0.01).

CONCLUSION

These findings suggest that (1) metalloproteases (MMP-1, MMP-2, MMP-7, and MMP-9) may play an important role in the remodeling of NPs and/or in NP formation and (2) a differential analysis of tissue structures and inflammatory cells should be performed when studying remodeling marker expression and regulation in the upper airways.

Staphylococcus aureus enterotoxin B-induced endoplasmic reticulum stress response is associated with chronic rhinosinusitis with nasal polyposis

OBJECTIVE

Staphylococcus aureus enterotoxin B (SEB) might participate in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). However, the exact mechanism of polyp formation in CRSwNP remains unclear. Since the endoplasmic reticulum (ER) stress response is closely associated with chronic inflammation, we investigated the association between ER stress and SEB in the pathogenesis of CRSwNP.

DESIGN AND METHODS

Twenty-three CRSwNP patients with eosinophilic polyps (EP) or non-eosinophilic polyps (NEP) and 10 healthy subjects who were undergoing septoplasty were enrolled in this study. ER stress response was investigated using immunohistochemical staining and Western blotting.

RESULTS

We show in this study that there are significantly more SEB-positive cells and higher production of reactive oxygen species (ROS) in the epithelial layer of EP than NEP or control tissue. Both SEB and protein A were detected strongly in tissues from patients with CRSwNP. We observed SEB induced the ER stress response in RPMI 2650 cells. GRP78 elevation by SEB was reduced by ROS scavenger pretreatment. In addition, the induction of GRP78 and p47 phox was increased significantly in EP compared with NEP or control mucosa.

CONCLUSIONS

SEB may induce ER stress via ROS production in CRSwNP. Therefore, we suggest that SEB-induced ER stress may play important roles in the pathogenesis of nasal polyposis.

Identifying intracellular Staphylococcus aureus in chronic rhinosinusitis: a direct comparison of techniques

BACKGROUND

The emerging concept of intracellular pathogens such as Staphylococcus aureus playing a role in chronic rhinosinusitis (CRS) has led to the development of numerous imaging techniques for their identification. Traditional methods of bacterial culture are not effective at localizing bacteria to the surface or within tissue samples. The aim of this study was to develop and validate a novel imaging technique using confocal scanning laser microscopy (CSLM) coupled with a fluorescence in situ hybridization (FISH) probe and nucleic acid counterstain (propidium iodide [PI]) that allows for simultaneous analysis of S. aureus intracellular status and surface biofilm within whole mucosal samples.

METHODS

A prospective study was performed including 17 patients undergoing endoscopic sinus surgery for CRS. Tissue samples were analyzed with both CSLM-FISH/PI and immunohistochemistry (IHC) for intracellular S. aureus status.

RESULTS

Using CSLM-FISH/PI intracellular S. aureus was identified in 9/17 (47%) patients and in 7/17 (39%) using IHC. Surface biofilm can be identified with CSLM-FISH/PI in the same piece of tissue; however, deeper imaging to the submucosa is impossible. IHC showed submucosal bacteria in three patients.

CONCLUSION

Both CSLM-FISH/PI and IHC are complementary techniques that can be used to identify intracellular S. aureus. CSLM-FISH/PI allows for the simultaneous detection of intracellular status and surface biofilm within the tissue analyzed. IHC has a role in the identification of intracellular and submucosal S. aureus within these tissues. Additional investigation is required to identify the true pathogenic nature of intracellular organisms as well as any relationship to surface biofilm status.

A time course study on the development of allergen-induced nasal airway remodeling in a rat model

BACKGROUND

Only a few studies have investigated the airway remodeling process in allergic rhinitis (AR), and the results reported are conflicting. We established an allergen-induced nasal remodeling model for AR using brown Norway rats and investigated time-dependent histological changes and the reversibility of the epithelial and subepithelial changes.

METHODS

Ovalbumin (OVA)-sensitized rats were exposed to OVA daily and then assigned to one of five groups depending on the duration of the challenge. Groups I, II, III, and IV rats were exposed for 1, 4, 8, and 12 weeks, respectively. Group V rats were exposed for 12 weeks and then protected from challenge for 4 weeks. Matched control rats were exposed to saline. Histological parameters of the nasal mucosa such as epithelial and subepithelial thickness, goblet cell hyperplasia, eosinophil infiltration, submucosal gland hypertrophy, and expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were compared between groups.

RESULTS

Repeated challenges for 12 weeks resulted in the characteristic features of nasal airway remodeling. All parameters except epithelial thickness increased markedly. Goblet cell hyperplasia and eosinophil infiltration decreased to control group levels after cessation of challenge for 4 weeks. Subepithelial changes such as subepithelial thickening, submucosal gland hypertrophy, and increased expression of MMP-9 and TIMP-1 were still observed after 4 weeks without challenge.

CONCLUSION

Our results indicate that prolonged OVA challenge can induce nasal remodeling. Epithelial changes were minimal or absent after cessation of the challenge, but subepithelial changes were resistant to reversal.

Convergence of two major pathophysiologic mechanisms in nasal polyposis: immune response to Staphylococcus aureus and airway remodeling

This review is addressed two pathophysiologic mechanisms implicated in the pathogenesis of nasal polyposis: the unique remodeling process found in nasal polyp tissue and the immune response of patients with nasal polyposis to Staphylococcus aureus.

These two theories converge to the same direction in different aspects, including decreased extracellular matrix production, impaired T regulation and favoring of a Th2 immune response.

In patients with nasal polyposis, an exaggerated immune response to Staphylococcus aureus may aggravate the airway remodeling process.

Intramucosal bacterial microcolonies exist in chronic rhinosinusitis without inducing a local immune response

BACKGROUND

Although chronic rhinosinusitis (CRS) causes very significant morbidity, much about its pathogenesis remains uncertain. Recent studies have identified polymicrobial biofilms on the surface of sinus mucosa and Staphylococcus aureus within the sinus mucosa of patients with CRS, both with and without nasal polyps. The pathogenic implications of intramucosal bacteria in CRS are unknown. This study was designed to determine the prevalence and species of bacterial colonies within the sinus mucosa of adult patients with and without CRS and to describe the relationship of these bacterial colonies to the host immune response.

METHODS

Sinus mucosa from patients with and without CRS was examined using Gram and Giemsa staining, immunohistochemistry, bacterial culture, and fluorescence in situ hybridization techniques.

RESULTS

Bacterial microcolonies were observed within the mucosa in 14 of 18 patients with CRS. In 10 of these patients colonies were positively identified as S. aureus. Staphylococcal microcolonies were observed at a lower level (1 of 8 patients) in normal sinus mucosa. There was no correlation between detection of S. aureus on the mucosal surface and microcolonization of the mucosa. Surprisingly, there was no evidence of an immune reaction to microcolonies. Indeed, fewer T lymphocytes (p = 0.03) and eosinophils (p = 0.03) were counted immediately surrounding the microcolonies compared with uninfected areas of the same tissue.

CONCLUSION

Bacterial microcolonies are prevalent within paranasal sinus mucosa and are commonly S. aureus. These microcolonies do not provoke immune detection and may represent a phenotype that actively evades host immunity. This may underpin the recalcitrance of CRS to antibiotic therapy. These findings challenge classic views of both infection and mucosal immunity in human chronic disease. The presence of intramucosal bacteria in samples of normal sinus mucosa also questions the sensitivity of detecting nasal carriage of pathogens by swabbing the surface of the anterior nares.

Matrix metalloproteinases and their impact on sinusal extension in chronic rhinosinusitis with nasal polyps

MMPs (metalloproteinases) and their inhibitor TIMP (tissue inhibitor of metalloproteinases) are important in tissue remodeling and have been implicated in nasal polyp pathophysiology. The objective of the present study was to evaluate gene expression of MMP-1, MMP-2, MMP-9 and TIMP-1 gene expression in nasal polyps and compare them with normal nasal mucosa. Since MMPs could induce a more prominent tissue edema, we also assessed if these gene expressions could be related to a more extensive disease. For the experimental study, 30 nasal polyp samples from patients with CRSwNP (Chronic Rhinosinusitis with Nasal Polyposis) and 19 middle turbinates (MT) from controls were obtained. Gene expression of MMP-1, MMP-2, MMP-9 and TIMP-1 was assessed by qRT-PCR. The expressions of these genes were compared between nasal polyps and controls and correlated to each individual Lund-Mackay score, MMP-1, MMP-2 and MMP-9 were significantly more expressed in nasal polyps than in controls (P < 0.005, P < 0.0001 and P < 0.05 respectively). No expression of TIMP-1 mRNA was detected. There was no correlation between disease extension evaluated by the Lund-Mackay score and MMPs gene expression. The present results demonstrate that there is a significantly higher mRNA gene expression of MMP-1, MMP-2 and MMP-9 in patients with CRSwNP than controls. However, no correlation was observed between MMPs gene expression and sinonasal CT scan extension.

LEVEL OF EVIDENCE

2c.

Prevalence and abundance of Staphylococcus aureus in the middle meatus of patients with chronic rhinosinusitis, nasal polyps, and asthma

BACKGROUND

Chronic rhinosinusitis (CRS) is an idiosyncratic and multifactorial disease process. Bacteria play a role in some patients, by infection or stimulation of inflammation. Staphylococcus aureus (SA) appears to be implicated in a number of infectious and inflammatory mechanisms, and may be particularly relevant in CRS patients with nasal polyps and asthma.

METHODS

Middle meatus swabs from control and CRS patients collected during endoscopic sinus surgery were analyzed by quantitative polymerase chain reaction (QPCR). Total bacterial count, SA prevalence, and SA abundance were examined with respect to patient demographics and disease characteristics.

RESULTS

Total bacteria, as measured by QPCR, was not statistically different between controls, CRS without nasal polyps (CRSsNP), CRS with nasal polyps (CRSwNP), or CRS with asthma groups (p < 0.09). Total bacterial counts did not correlate with disease severity as measured by Lund-Mackay computed tomography (CT) scores (p = 0.65). The prevalence of SA was similar between groups (15-25%); however, the abundance increased in CRS patients with allergic rhinitis, nasal polyps, and asthma.

CONCLUSION

The paranasal sinuses are not sterile. SA is implicated in a subset of CRS patients with nasal polyps and/or asthma. Further study is required to predict this subset of patients, and to define the mechanisms of SA pathogenesis.

Corelationship between matrix metalloproteinase 2 and 9 expression and severity of chronic rhinosinusitis with nasal polyposis

BACKGROUND

Matrix metalloproteinase (MMP) is involved in the remodeling process of inflammatory airway diseases and is correlated with the severity of asthma. We hypothesized that MMP was associated with the severity of chronic rhinosinusitis with nasal polyps (CRSwNPs). We also investigated the effect of allergy on the expression of MMP in the polyp.

METHODS

The expression of MMP-2 and -9 was investigated in recurrent nasal polyps of 30 patients and in nonrecurrent nasal polyps of 31 patients undergoing endoscopic sinus surgery. These expressions were then compared with those in control nasal mucosal samples obtained from 32 patients with chronic hypertrophic rhinitis. Demographic data, Lund-Mackay (LM) score, polyp grade, and allergy status were obtained for all patients. Tissue samples were assessed via immunohistochemistry.

RESULTS

MMP-2 and -9 were constantly expressed in recurrent NPs, primary NPs, and control nasal mucosa. The expression of MMP-9 was significantly enhanced in glands and MMP-2 positivity was significantly increased in surface epithelium for patients with NPs when compared with control nasal mucosa. The expression of MMP-9 and -2 was not correlated with polyp grade and LM score. Allergic status is an independent factor in the expression of MMP-2 and -9.

CONCLUSION

These results suggested up-regulation of MMP-9, and MMP-2 in gland and surface epithelium, respectively, were characteristic of NPs. Therefore, patients with allergy will exhibit greater MMP-2 and -9 positivity. However, the MMP-2 and -9 expression intensity was not correlated with the severity of CRS with nasal polyposis.

Pathophysiology, favoring factors, and associated disorders in otorhinosinusology

The pathogenesis of rhinosinusitis (RS) is related to inflammation, caused by infections in the acute form of the disease but also by other agents in the chronic forms. Cytology allows to evaluate the defensive components, such as hair cells and muciparous cells, while the presence in the nasal mucosa of eosinophils, mast cells, bacteria and/or fungal hyphae, or spores indicates the nasal pathology. The anatomic and physiologic characteristics of the otorhinosinusal system account for the frequent concomitant involvement of the different components. The pivotal pathophysiologic sites are the ostiomeatal complex, the spheno-ethmoidal recess, and the Eustachian tube. The latter is the link with acute otitis media (AOM), which is the most common disease in infants and children and has major medical, social, and economic effects. Moreover, because of the strict relationship between upper and lower airways, nasal sinus disease may contribute to asthma and sinusitis may be considered as an independent factor associated with frequent severe asthma exacerbations. Concerning the role of allergy, the available data do not permit to attribute a central role to atopy in sinusitis and thus allergy testing should not be a routine procedure, while an allergologic evaluation may be indicated in children with OM, especially when they have concomitant rhinitis.

The effect of passive smoking on the levels of matrix metalloproteinase 9 in nasal secretions of children

BACKGROUND

Matrix metalloproteinase (MMP) 9 is a gelatinase associated with tissue remodeling. It is thought to play a part in the pathogenesis of allergy. Increased levels of MMP-9 have been shown to increase in the acute allergic response in the nose, lungs, and skin. Exposure to passive tobacco smoke is associated with an increase in sneezing, nasal blockage, and a decreased sense of smell. The aim of this study was to study the effect of passive smoking on the levels of MMP-9 in nasal secretions of children.

METHODS

A prospective descriptive study was performed. Thirty-nine children aged between 7 and 16 years were enrolled in the study. They were selected based on attendance at the Otorhinolaryngology Outpatients Clinic with a primary complaint unrelated to the nose or paranasal sinuses. Children with allergic rhinitis, sinusitis, or a recent cold were excluded. The study was performed at a tertiary pediatric referral center. Exposure to passive smoking was determined by measuring the urinary cotinine to creatinine ratio. Nasal fluid was obtained by using a Rhino-Probe curette (Arlington Scientific, Inc., Springville, UT). The concentration of MMP-9 was determined by ELISA. MMP-9 activity was determined by gelatin zymography. Data were tabulated on Microsoft Excel (Microsoft Corp., Redmond, WA) and analyzed using SPSS (SPSS Inc., Chicago, IL).

RESULTS

Using a cutoff urinary cotinine/creatinine ratio of 0.025 ng/mg, 15 children were found to be exposed to passive smoking. Both the MMP-9 concentration and the activity were significantly higher in nasal secretions of children exposed to passive smoking. There was a distinct difference between the two cohorts with regard to the level of enzyme activity per weight of protein. The lowest level of enzyme activity recorded in the "exposed" cohort was over twice that of the level in the "not exposed" cohort.

CONCLUSION

MMP-9 activity and concentration is higher in nasal secretions of children exposed to passive smoking. This suggests that passive smoking might alter the inflammatory response within the nasal mucosa in a similar way to allergy.

Nasal disease and asthma

The nose plays a primary role within the airways, working as a filter and air-conditioner, together with other important functions. Thus, it is not surprising that nasal diseases are associated with several other comorbidities, including both upper and lower airways, such as bronchial hyperresponsiveness (BHR) and asthma. Several studies have investigated the relationship existing between the upper and the lower airways and new insights are rising. Nevertheless, some uncertainties still remain, mainly because nasal disorders are quite heterogeneous, overlapping (i.e. rhinitis-rhinosinusitis-sinusitis, acute or chronic, allergic or non-allergic) and difficult to diagnose, so that, frequently, many studies don’t differentiate between the various conditions. For this reason, the purpose of this review is to systematically analyze present epidemiological, pathophysiological and clinical data on the relationship between nasal diseases and asthma, splitting up three main conditions: allergic rhinitis, chronic rhinosinusitis and nasal polyposis.

Levocetirizine Inhibits Rhinovirus-Induced Up-Regulation of Fibrogenic and Angiogenic Factors in Nasal Polyp Fibroblasts

Background

Up-regulation of matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF), and transforming growth factor (TGF) beta, may contribute to the formation of nasal polyps (NPs). Rhinovirus (RV) infection enhances expression of MMP-2, MMP-9, and VEGF in NP fibroblasts and of TGF-beta in respiratory epithelial cells. We investigated the inhibitory effects of levocetirizine (LCT) on the RV-induced expression of (1) fibrogenic (MMPs and TGF-beta) and (2) angiogenic (VEGF and TGF-beta) factors in NP fibroblasts.

Methods

NP fibroblasts obtained from 11 male patients with chronic rhinosinusitis with NPs (CRSwNPs), were infected with RV serotype 16 (RV-16) for 4 hours. Cells were treated with 50 nM of LCT 24 hours before infection and for 48 hours thereafter. Expression of MMP-2, MMP-9, VEGF, and TGF-β mRNA and protein were determined by real-time polymerase chain reaction and enzyme-linked immunosorbent assays, respectively.

Results

LCT significantly inhibited RV-induced increases in MMP-2, MMP-9, VEGF, and TGF-beta mRNA, and protein expression, in NP fibroblasts (p < 0.05 for each comparison).

Conclusion

LCT inhibits RV-induced up-regulation of fibrogenic and angiogenic factors in NP fibroblasts, suggesting that LCT may prevent NP formation in patients with CRSwNP caused by RV infection.

The links between chronic rhinosinusitis and asthma

PURPOSE OF REVIEW

Chronic rhinosinusitis (CRS) and asthma are two leading causes of morbidity with many shared clinical features. Their relationship has initially been linked by the atopic pathway. However, understanding of the true pathophysiology of each of these conditions is still under investigation.

RECENT FINDINGS

Recent studies have described new common pathogens, such as fungi and Staphylococcus aureus, as well as disease biomarkers such as nitric oxide and interleukin (IL)-17A, involved in both asthma and CRS pathophysiology. These new discoveries offer insight into understanding these upper and lower airway diseases and may potentially affect treatment management. In the following review, we intend to provide an overview of the recent developments in the relevant areas of research within the past year.

SUMMARY

Reactions to fungal stimuli and superantigens, as well as biomarkers such as nitric oxide and IL-17A, may play a role in the pathogenesis of asthma and CRS and may explain their historic relationship.

Pathophysiology of Chronic Rhinosinusitis with Nasal Polyp

Background

Chronic rhinosinusitis (CRS) is a common inflammatory condition of the paranasal sinuses and nasal passages. CRS with nasal polyp (CRSwNP) is a subtype of CRS, and the pathogenesis of CRSwNP remains largely unclear.

Methods

This article reviews the literature regarding the pathophysiology of CRSwNP.

Results

Evidence suggests that altered innate immunity, adaptive immunity, tissue remodeling, and/or effects of microorganisms may play a role in the development of CRSwNP. Aberrant arachidonic acid metabolism may also contribute to the pathogenesis of CRSwNP in patients with aspirin-exacerbated respiratory disease.

Conclusion

There have been significant advances in the understanding pathophysiology of CRSwNP. Additional research is needed to elucidate these mechanisms and to determine their relative importance in the pathogenesis of CRSwNP.