Activation of airway epithelial bitter taste receptors by Pseudomonas aeruginosa quinolones modulates calcium, cyclic-AMP, and nitric oxide signaling.

Bitter taste receptors (taste family 2 bitter receptor proteins; T2Rs), discovered in many tissues outside the tongue, have recently become potential therapeutic targets. We have shown previously that airway epithelial cells express several T2Rs that activate innate immune responses that may be important for treatment of airway diseases such as chronic rhinosinusitis. It is imperative to more clearly understand what compounds activate airway T2Rs as well as their full range of functions. T2R isoforms in airway motile cilia (T2R4, -14, -16, and -38) produce bactericidal levels of nitric oxide (NO) that also increase ciliary beating, promoting clearance of mucus and trapped pathogens. Bacterial quorum-sensing acyl-homoserine lactones activate T2Rs and stimulate these responses in primary airway cells. Quinolones are another type of quorum-sensing molecule used by Pseudomonas aeruginosa To elucidate whether bacterial quinolones activate airway T2Rs, we analyzed calcium, cAMP, and NO dynamics using a combination of fluorescent indicator dyes and FRET-based protein biosensors. T2R-transfected HEK293T cells, several lung epithelial cell lines, and primary sinonasal cells grown and differentiated at the air-liquid interface were tested with 2-heptyl-3-hydroxy-4-quinolone (known as Pseudomonas quinolone signal; PQS), 2,4-dihydroxyquinolone, and 4-hydroxy-2-heptylquinolone (HHQ). In HEK293T cells, PQS activated T2R4, -16, and -38, whereas HHQ activated T2R14. 2,4-Dihydroxyquinolone had no effect. PQS and HHQ increased calcium and decreased both baseline and stimulated cAMP levels in cultured and primary airway cells. In primary cells, PQS and HHQ activated levels of NO synthesis previously shown to be bactericidal. This study suggests that airway T2R-mediated immune responses are activated by bacterial quinolones as well as acyl-homoserine lactones.

Protease-activated receptor 2 activates airway apical membrane chloride permeability and increases ciliary beating.

Mucociliary clearance, driven by the engine of ciliary beating, is the primary physical airway defense against inhaled pathogens and irritants. A better understanding of the regulation of ciliary beating and mucociliary transport is necessary for identifying new receptor targets to stimulate improved clearance in airway diseases, such as cystic fibrosis and chronic rhinosinusitis. In this study, we examined the protease-activated receptor (PAR)-2, a GPCR previously shown to regulate airway cell cytokine and mucus secretion, and transepithelial Cl- current. PAR-2 is activated by proteases secreted by airway neutrophils and pathogens. We cultured various airway cell lines, primary human and mouse sinonasal cells, and human bronchial cells at air-liquid interface and examined them using molecular biology, biochemistry, and live-cell imaging. We found that PAR-2 is expressed basolaterally, where it stimulates both intracellular Ca2+ release and Ca2+ influx, which activates low-level nitric oxide production, increases apical membrane Cl- permeability ∼3-5-fold, and increases ciliary beating ∼20-50%. No molecular or functional evidence of PAR-4 was observed. These data suggest a novel and previously overlooked role of PAR-2 in airway physiology, adding to our understanding of the role of this receptor in airway Ca2+ signaling and innate immunity.-McMahon, D. B., Workman, A. D., Kohanski, M. A., Carey, R. M., Freund, J. R., Hariri, B. M., Chen, B., Doghramji, L. J., Adappa, N. D., Palmer, J. N., Kennedy, D. W., Lee, R. J. Protease-activated receptor 2 activates airway apical membrane chloride permeability and increases ciliary beating.

Solitary chemosensory cells are a primary epithelial source of IL-25 in patients with chronic rhinosinusitis with nasal polyps.

BACKGROUND: IL-25 can function as an early signal for the respiratory type 2 response characteristic of allergic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP). In the mouse gut, tuft cells are the epithelial source of IL-25. However, the source of human airway epithelial IL-25 has remained elusive. OBJECTIVE: In this study we sought to determine whether the solitary chemosensory cell (SCC) is the predominant source of IL-25 in the sinonasal epithelium. METHOD: Flow cytometry and immunofluorescence for SCCs and IL-25 were used to interrogate polyp and turbinate tissue from patients with CRSwNP. Mucus was collected during acute inflammatory exacerbations from patients with CRSwNP or chronic rhinosinusitis without nasal polyps and IL-25 levels determined by using ELISA. Lastly, sinonasal epithelial cultures derived from polyp and turbinate tissue were stimulated with IL-13 and analyzed for SCC proliferation and IL-25 production. RESULTS: This study demonstrates that a discrete cell type, likely an SCC, characterized by expression of the taste-associated G protein gustducin and the intestinal tuft cell marker doublecortin-like kinase 1, is the predominant source of IL-25 in the human upper airway. Additionally, we show that patients with CRSwNP have increased numbers of SCCs in nasal polyp tissue and that in vitro IL-13 exposure both increased proliferation and induced apical secretion of IL-25 into the mucosal layer. CONCLUSIONS: Inflammatory sinus polyps but not adjacent turbinate tissue show expansion of the SCC population, which is the source of epithelial IL-25.

Flavones modulate respiratory epithelial innate immunity: Anti-inflammatory effects and activation of the T2R14 receptor.

Chronic rhinosinusitis has a significant impact on patient quality of life, creates billions of dollars of annual healthcare costs, and accounts for ∼20% of adult antibiotic prescriptions in the United States. Because of the rise of resistant microorganisms, there is a critical need to better understand how to stimulate and/or enhance innate immune responses as a therapeutic modality to treat respiratory infections. We recently identified bitter taste receptors (taste family type 2 receptors, or T2Rs) as important regulators of sinonasal immune responses and potentially important therapeutic targets. Here, we examined the immunomodulatory potential of flavones, a class of flavonoids previously demonstrated to have antibacterial and anti-inflammatory effects. Some flavones are also T2R agonists. We found that several flavones inhibit Muc5AC and inducible NOS up-regulation as well as cytokine release in primary and cultured airway cells in response to several inflammatory stimuli. This occurs at least partly through inhibition of protein kinase C and receptor tyrosine kinase activity. We also demonstrate that sinonasal ciliated epithelial cells express T2R14, which closely co-localizes (<7 nm) with the T2R38 isoform. Heterologously expressed T2R14 responds to multiple flavones. These flavones also activate T2R14-driven calcium signals in primary cells that activate nitric oxide production to increase ciliary beating and mucociliary clearance. TAS2R38 polymorphisms encode functional (PAV: proline, alanine, and valine at positions 49, 262, and 296, respectively) or non-functional (AVI: alanine, valine, isoleucine at positions 49, 262, and 296, respectively) T2R38. Our data demonstrate that T2R14 in sinonasal cilia is a potential therapeutic target for upper respiratory infections and that flavones may have clinical potential as topical therapeutics, particularly in T2R38 AVI/AVI individuals.

Vasoactive intestinal peptide regulates sinonasal mucociliary clearance and synergizes with histamine in stimulating sinonasal fluid secretion.

Mucociliary clearance (MCC) is the primary physical airway defense against inhaled pathogens and particulates. MCC depends on both proper fluid/mucus homeostasis and epithelial ciliary beating. Vasoactive intestinal peptide (VIP) is a neurotransmitter expressed in the sinonasal epithelium that is up-regulated in allergy. However, the effects of VIP on human sinonasal physiology are unknown, as are VIP's interactions with histamine, a major regulator of allergic disease. We imaged ciliary beat frequency, mucociliary transport, apical Cl(-) permeability, and airway surface liquid (ASL) height in primary human sinonasal air-liquid-interface cultures to investigate the effects of VIP and histamine. VIP stimulated an increase in ciliary beat frequency (EC50 0.5 µM; maximal increase ∼40% compared with control) and cystic fibrosis transmembrane conductance regulator (CFTR)-dependent and Na(+)K(+)2Cl(-) cotransporter-dependent fluid secretion, all requiring cAMP/PKA signaling. Histamine activated Ca(2+) signaling that increased ASL height but not ciliary beating. Low concentrations of VIP and histamine had synergistic effects on CFTR-dependent fluid secretion, revealed by increased ASL heights. An up-regulation of VIP in histamine-driven allergic rhinitis would likely enhance mucosal fluid secretion and contribute to allergic rhinorrhea. Conversely, a loss of VIP-activated secretion in patients with CF may impair mucociliary transport, contributing to increased incidences of sinonasal infections and rhinosinusitis.

Divergent bitter and sweet taste perception intensity in chronic rhinosinusitis patients.

BACKGROUND: Bitter and sweet taste receptors are present in the human upper airway, where they have roles in innate immunity. Previous studies have shown that 1 of the 25 bitter receptors, TAS2R38, responds to specific bacterial signaling molecules and evokes 1 type of a defense response in the upper airway, whereas ligands of sweet receptors suppress other types of defense responses. METHODS: We examined whether other bitter taste receptors might also be involved in innate immunity by using sensory responses to bitter compounds that are not ligands of TAS2R38 (quinine and denatonium benzoate) to assess the sensitivity of other bitter receptors in chronic rhinosinusitis (CRS) patients. CRS patients with (n = 426) and without (n = 226) nasal polyps and controls (n = 356) rated the intensity of quinine, denatonium benzoate, phenylthiocarbamide (PTC; a ligand for TAS2R38), sucrose, and salt. RESULTS: CRS patients rated the bitter compounds denatonium benzoate and quinine as less intense and sucrose as more intense than did controls (false discovery rate [FDR] <0.05) and CRS patients and controls did not differ in their ratings of salt (FDR >0.05). PTC bitter taste intensity differed between patient and control groups but were less marked than those previously reported. Though differences were statistically significant, overall effect sizes were small. CONCLUSION: CRS patients report bitter stimuli as less intense but sweet stimuli as more intense than do control subjects. We speculate that taste responses may reflect the competence of sinonasal innate immunity mediated by taste receptor function, and thus a taste test may have potential for clinical utility in CRS patients.

Olfactory dysfunction in allergic rhinitis.

BACKGROUND: Olfactory dysfunction in patients with allergic rhinitis has long been thought to be secondary to coexisting chronic rhinosinusitis and polyposis with obstruction of airflow over the olfactory epithelium. Recent evidence suggests that the allergic inflammatory infiltrate may itself affect olfaction in the absence of mucosal hypertrophy. OBJECTIVE: We undertook a study to determine olfactory function in patients with allergic rhinitis in the presence and absence of chronic sinusitis. METHODS: Fifty-one subjects with symptoms of rhinitis who presented for allergy testing were administered the University of Pennsylvania Smell Identification Test. In addition each patient underwent computed tomography (CT) scanning of the sinuses. RESULTS: Eighty percent of subjects were allergic. Subjects with allergic rhinitis and no evidence of sinusitis scored on average in the 30th percentile (95% CI 20-40th percentile) on objective olfactory testing compared to age- and gender-specific norms. Half the allergic patients were classified as normosmic, while half had some degree of hyposmia. CONCLUSIONS: Our study demonstrates that even in the absence of mucosal disease on CT scan, a significant subset of patients with allergic rhinitis will exhibit hyposmia, mostly to a mild or moderate degree. The pathophysiology and potential treatments for olfactory loss in these patients should be further explored.

Fluoroquinolone-resistant Pseudomonas aeruginosa in chronic rhinosinusitis.

BACKGROUND: Pseudomonas aeruginosa is cultured in nearly 1 of 5 patients with chronic rhinosinusitis and a history of sinus surgery. Fluoroquinolones are the only enterally administered antibiotics with efficacy against P. aeruginosa, but their frequent empiric use in the community raises concern for a rise in resistance. OBJECTIVE: It was the aim of this study to determine the prevalence of fluoroquinolone-resistant P. aeruginosa in a tertiary rhinology practice. METHODS: All bacterial sinus culture results from the outpatient otolaryngology clinic that yielded P. aeruginosa over a 5-year period (2002-2007) were reviewed along with the medical records of a randomly selected subset of patients. RESULTS: In total, 689 culture results of 324 patients were examined. Nearly all patients had a history of endoscopic sinus surgery. Of all P. aeruginosa cultured, 13% were resistant to levofloxacin and 5% were intermediately sensitive, while 5% were resistant to ciprofloxacin and 7% intermediately sensitive. Of the 324 patients in the study, 19 and 15% had a history of a P. aeruginosa culture resistant to levofloxacin or ciprofloxacin, respectively. Mucoid strains of P. aeruginosa were significantly more likely to be fluoroquinolone resistant. No patient comorbidities were associated with a higher rate of resistance. The prevalence of resistant cultures remained stable over the 5-year study period. CONCLUSIONS: P. aeruginosa is cultured primarily in patients with previous sinus surgery. Nearly 20% of isolates are resistant to fluoroquinolones. Resistance to levofloxacin is more common than resistance to ciprofloxacin. This study supports the use of culture-directed therapy in the management of the postfunctional endoscopic sinus surgery patient and the avoidance of empiric use of fluoroquinolones.

Alcohol-induced respiratory symptoms improve after aspirin desensitization in patients with aspirin-exacerbated respiratory disease.

BACKGROUND: Aspirin-exacerbated respiratory disease (AERD) is characterized by chronic eosinophilic rhinosinusitis, nasal polyps, asthma, and respiratory sensitivity to aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). In addition to sensitivity to aspirin and NSAIDs, the majority of patients with AERD have been reported to have respiratory intolerance associated with the consumption of alcohol. METHODS: A multicenter prospective cohort study was performed. Patients with AERD confirmed by aspirin challenge were eligible to participate. Those who described themselves as able to tolerate alcohol consumption were excluded. Patients underwent aspirin desensitization following endoscopic sinus surgery. A questionnaire was distributed to patients before and after desensitization to determine pre-desensitization and post-desensitization symptoms associated with alcohol ingestion. RESULTS: Forty-five patients were enrolled and 37 patients completed the study. The most common pre-desensitization symptoms were nasal congestion (95.6%), rhinorrhea (46.7%), and wheezing (40%). Improvement in the ability to tolerate alcohol was noted in 86.5% of participants (95% confidence interval [CI], 75.5% to 97.5%) and 70.3% of participants (95% CI, 55.5% to 85.0%) described desensitization to be "very helpful" or "extremely helpful" for their ability to tolerate alcohol. CONCLUSION: The majority of patients with AERD who experience respiratory symptoms with alcohol consumption describe improvement in this domain following aspirin desensitization.

Preoperative Lund-Mackay computed tomography score is associated with preoperative symptom severity and predicts quality-of-life outcome trajectories after sinus surgery.

BACKGROUND: Disagreement exists about the relationship between Lund-Mackay CT scores (LMCTS) and quality-of-life outcome (QoL) measures. We investigated whether preoperative LMCTS are associated with preoperative QoL, and whether LMCTS is predictive of postoperative QoL outcomes in chronic rhinosinusitis (CRS) patients. METHODS: Adult patients with medically recalcitrant CRS (n = 665) were enrolled in a prospective, observational cohort study. Preoperative LMCTS and pre- and postoperative self-reported QoL outcomes (22-item Sino-Nasal Outcomes Test [SNOT-22]) were collected and evaluated over 12 months. Five hundred sixty-eight patients met the inclusion criteria. Longitudinal linear mixed-effects modeling was used to investigate the effect of LMCTS on QoL after functional endoscopic sinus surgery (FESS). RESULTS: Preoperative LMCTS were significantly associated with preoperative SNOT-22 scores (p < 0.01) and postoperative SNOT-22 scores (p < 0.001), driven by Extranasal and Rhinologic subdomains of the QoL questionaire. Patients in the lowest preoperative LMCTS quartile had the lowest mean change in SNOT-22 scores at 12 months (16.8 points; 95% confidence interval [CI], 12.2-21.3). Patients in the second and third lowest preoperative LMCTS quartiles had mean changes at 12 months of 21.1 points (95% CI, 16.7-25.4) and 23.1 points (95% CI, 18.3-27.9). Patients in the highest preoperative LMCTS quartile had the greatest improvement in SNOT-22 scores after FESS (29.9 points; 95% CI, 24.9-34.8). The difference in QoL change at 12 months between the highest and lowest preoperative LMCTS quartiles was 13.1 points (95% CI, 6.0-20.2; p < 0.001). CONCLUSION: Our study demonstrates that preoperative LMCTS correlate with preoperative extranasal and rhinologic symptom severity and that the LMCTS is an indicator of postsurgical QoL outcomes for medically recalcitrant chronic rhinosinusitis patients in a large tertiary otolaryngology setting.

Bacterial d-amino acids suppress sinonasal innate immunity through sweet taste receptors in solitary chemosensory cells.

In the upper respiratory epithelium, bitter and sweet taste receptors present in solitary chemosensory cells influence antimicrobial innate immune defense responses. Whereas activation of bitter taste receptors (T2Rs) stimulates surrounding epithelial cells to release antimicrobial peptides, activation of the sweet taste receptor (T1R) in the same cells inhibits this response. This mechanism is thought to control the magnitude of antimicrobial peptide release based on the sugar content of airway surface liquid. We hypothesized that d-amino acids, which are produced by various bacteria and activate T1R in taste receptor cells in the mouth, may also activate T1R in the airway. We showed that both the T1R2 and T1R3 subunits of the sweet taste receptor (T1R2/3) were present in the same chemosensory cells of primary human sinonasal epithelial cultures. Respiratory isolates of Staphylococcus species, but not Pseudomonas aeruginosa, produced at least two d-amino acids that activate the sweet taste receptor. In addition to inhibiting P. aeruginosa biofilm formation, d-amino acids derived from Staphylococcus inhibited T2R-mediated signaling and defensin secretion in sinonasal cells by activating T1R2/3. d-Amino acid-mediated activation of T1R2/3 also enhanced epithelial cell death during challenge with Staphylococcus aureus in the presence of the bitter receptor-activating compound denatonium benzoate. These data establish a potential mechanism for interkingdom signaling in the airway mediated by bacterial d-amino acids and the mammalian sweet taste receptor in airway chemosensory cells.

Correlation of T2R38 taste phenotype and in vitro biofilm formation from nonpolypoid chronic rhinosinusitis patients.

BACKGROUND: Sinonasal biofilms have been demonstrated in specimens collected from chronic rhinosinusitis (CRS) patients. Mounting evidence suggests that biofilms contribute to therapeutically recalcitrant CRS. Recently, the bitter taste receptor T2R38 has been implicated in the regulation of the sinonasal mucosal innate immune response. TAS2R38 gene polymorphisms affect receptor functionality and contribute to variations seen in sinonasal innate defense as well as taste perception reflected in gustatory sensitivity to the bitter compound phenylthiocarbamide (PTC). In a population of CRS patients with active infection or inflammation, we sought to determine if a correlation between T2R38 phenotype and in vitro biofilm formation existed. METHODS: Endoscopically guided sinonasal swabs were obtained prospectively from CRS (±polyp) patients with evidence of persistent inflammation or mucopurulence. In vitro biofilm formation was assessed with a modified Calgary Biofilm Detection Assay. Patients' phenotypic (functional) expression of the bitter taste receptor T2R38 was evaluated with a taste test including the compound PTC. Linear regression was used to determine the level of significance between mean in vitro biofilm formation levels and mean PTC taste test intensity ratings across CRS patients. RESULTS: Sinonasal swabs were obtained from 59 patients, with 42 of the 59 samples demonstrating in vitro biofilm formation. Analysis revealed an inverse linear association between in vitro biofilm formation and PTC taste intensity ratings (p = 0.019) for all patients. This association was exclusively driven by nonpolypoid CRS patients (p = 0.0026). CONCLUSION: In vitro biofilm formation from sinonasal clinical isolates is inversely correlated with PTC taste sensitivity in nonpolypoid CRS patients.

TAS2R38 genotype predicts surgical outcome in nonpolypoid chronic rhinosinusitis.

BACKGROUND: Over 550,000 sinus surgeries are performed annually in the United States on patients with chronic rhinosinusitis (CRS). Although the results of sinus surgery vary widely, no known genetic factor has been identified to predict surgical outcomes. The bitter taste receptor T2R38 has recently been demonstrated to regulate upper airway innate defense and may affect patient responses to therapy. Our goal was to determine whether TAS2R38 genetics predicts outcomes in CRS patients following sinus surgery. METHODS: A prospective study of patients undergoing sinus surgery evaluating postoperative outcomes through the 22-item Sino-Nasal Outcome Test (SNOT-22). Patients were genotyped for TAS2R38. RESULTS: A total of 123 patients with CRS were initially analyzed; 82 patients showed nasal polyps (CRSwNP) and 41 patients were without nasal polyps (CRSsNP). Six months after surgery, the overall SNOT-22 improvement was 25 ± 23 points. The TAS2R38 genotype was found to significantly correlate with surgical outcomes in patients without polyps; homozygotes for the functional receptor had a mean improvement of 38 ± 21, whereas heterozygotes or homozygotes for the nonfunctional receptor had a mean improvement of 12 ± 22 (p = 0.006). This result was confirmed with a multivariate regression that incorporated further patients with 1-month and 3-month scores (n = 207). CONCLUSION: In patients undergoing sinus surgery for CRS, we have identified a genetic polymorphism that predicts variability in quality of life improvement following surgery at 6 months in nonpolypoid CRS. This is the first genetic polymorphism identified that has demonstrated to predict surgical outcome for a select group of CRS patients.

In vitro effects of anthocyanidins on sinonasal epithelial nitric oxide production and bacterial physiology.

BACKGROUND: T2R bitter taste receptors play a crucial role in sinonasal innate immunity by upregulating mucociliary clearance and nitric oxide (NO) production in response to bitter gram-negative quorum-sensing molecules in the airway surface liquid. Previous studies showed that phytochemical flavonoid metabolites, known as anthocyanidins, taste bitter and have antibacterial effects. Our objectives were to examine the effects of anthocyanidins on NO production by human sinonasal epithelial cells and ciliary beat frequency, and their impact on common sinonasal pathogens Pseudomonas aeruginosa and Staphylococcus aureus. METHODS: Ciliary beat frequency and NO production were measured by using digital imaging of differentiated air-liquid interface cultures prepared from primary human cells isolated from residual surgical material. Plate-based assays were used to determine the effects of anthocyanidins on bacterial swimming and swarming motility. Biofilm formation and planktonic growth were also assessed. RESULTS: Anthocyanidin compounds triggered epithelial cells to produce NO but not through T2R receptors. However, anthocyanidins did not impact ciliary beat frequency. Furthermore, they did not reduce biofilm formation or planktonic growth of P. aeruginosa. In S. aureus, they did not reduce planktonic growth, and only one compound had minimal antibiofilm effects. The anthocyanidin delphinidin and anthocyanin keracyanin were found to promote bacterial swimming, whereas anthocyanidin cyanidin and flavonoid myricetin did not. No compounds that were tested inhibited bacterial swarming. CONCLUSION: Results of this study indicated that, although anthocyanidins may elicited an innate immune NO response from human cells, they do not cause an increase in ciliary beating and they may also cause a pathogenicity-enhancing effect in P. aeruginosa. Additional studies are necessary to understand how this would affect the use of anthocyanidins as therapeutics. This study emphasized the usefulness of in vitro screening of candidate compounds against multiple parameters of both epithelial and bacterial physiologies to prioritize candidates for in vivo therapeutic testing.

T2R38 genotype is correlated with sinonasal quality of life in homozygous ΔF508 cystic fibrosis patients.

BACKGROUND: Chronic rhinosinusitis (CRS) is very prevalent in the cystic fibrosis (CF) patient population, and leads to high morbidity and markedly decreased quality of life (QOL). Identification of genetic markers that contribute to CRS symptoms in these patients can allow for risk stratification and tailoring of medical and surgical treatments. T2R38 is a bitter taste receptor expressed in the sinonasal tract, and nonfunctional alleles of this receptor have been implicated in treatment-refractory CRS in non-CF patients. The purpose of this study is to investigate the significance of T2R38 genotype in the variability of sinonasal QOL and CRS disease severity in a sample of CF patients. METHODS: ΔF508 homozygous CF patients were recruited from the University of Pennsylvania Cystic Fibrosis Center and were genotyped for the TAS2R38 locus. To assess sinonasal symptom severity, a 22-item Sino-Nasal Outcome Test (SNOT-22) was collected from each patient. Additional demographic and medical history data was obtained at the time of patient enrollment. RESULTS: A total of 49 ΔF508 homozygous CF patients aged 18 to 32 years were included in the final SNOT-22 score analysis. Individuals with 2 functional T2R38 alleles (PAV/PAV) had significantly lower SNOT-22 scores (n = 49, p < 0.05). On further breakdown of SNOT-22 subcategories, rhinologic symptoms specifically were less severe in PAV/PAV patients than patients with other genotypes (n = 47, p < 0.05). CONCLUSION: Our investigation indicates that T2R38 genotype correlates both with SNOT-22 scores and rhinologic-specific QOL in ΔF508 homozygous CF patients.

Fungal Aflatoxins Reduce Respiratory Mucosal Ciliary Function.

Aflatoxins are mycotoxins secreted by Aspergillus flavus, which can colonize the respiratory tract and cause fungal rhinosinusitis or bronchopulmonary aspergillosis. A. flavus is the second leading cause of invasive aspergillosis worldwide. Because many respiratory pathogens secrete toxins to impair mucociliary immunity, we examined the effects of acute exposure to aflatoxins on airway cell physiology. Using air-liquid interface cultures of primary human sinonasal and bronchial cells, we imaged ciliary beat frequency (CBF), intracellular calcium, and nitric oxide (NO). Exposure to aflatoxins (0.1 to 10 µM; 5 to 10 minutes) reduced baseline (~6-12%) and agonist-stimulated CBF. Conditioned media (CM) from A. fumigatus, A. niger, and A. flavus cultures also reduced CBF by ~10% after 60 min exposure, but effects were blocked by an anti-aflatoxin antibody only with A. flavus CM. CBF reduction required protein kinase C but was not associated with changes in calcium or NO. However, AFB2 reduced NO production by ~50% during stimulation of the ciliary-localized T2R38 receptor. Using a fluorescent reporter construct expressed in A549 cells, we directly observed activation of PKC activity by AFB2. Aflatoxins secreted by respiratory A. flavus may impair motile and chemosensory functions of airway cilia, contributing to pathogenesis of fungal airway diseases.

Coagulase-negative Staphylococcus culture in chronic rhinosinusitis.

BACKGROUND: Coagulase-negative Staphylococcus (CoNS) is commonly isolated from patients with chronic rhinosinusitis (CRS). However, the role of CoNS in CRS remains controversial. We aimed to determine the association between positive CoNS culture at functional endoscopic sinus surgery (FESS) and CRS severity. METHODS: Adult CRS patients who underwent FESS between October 1, 2007 to December 31, 2011 were recruited. Patient demographics, disease characteristics, medication use, Lund-Mackay computed tomography (CT) scores, and 22-item Sino-Nasal Outcome Test (SNOT-22) scores were collected at baseline before FESS. Intraoperative cultures were obtained in a standard manner. Patients were placed into 2 groups based on culture findings: patients with CoNS as the sole positive culture result and patients with all other positive culture results, including CoNS, as part of a polymicrobial culture. RESULTS: A total of 376 CRS patients met the criteria; 106 patients (28%) had CoNS as their only isolate, 260 (69%) had other positive cultures, and 10 (3%) had no bacterial growth. Compared to patients with other positive cultures, patients with the sole result of CoNS were significantly less likely to have a history of FESS (52% vs 65%, p = 0.019), nasal polyps (50% vs 65%, p = 0.006), and had a better Lund-Mackay CT score (11.95 vs 14.18, p = 0.020). After adjusting for all factors in the multiple logistic regression model, CoNS as the sole positive culture result was independently associated with having no history of FESS (odds ratio [OR] = 0.45; 95% confidence interval [CI], 0.22 to 0.94; p = 0.034). CONCLUSION: Positive intraoperative CoNS cultures alone do not result in increased CRS disease burden by objective or subjective measures as compared to patients with other bacterial or polymicrobial culture isolates.

Different clinical factors associated with Staphylococcus aureus and Pseudomonas aeruginosa in chronic rhinosinusitis.

BACKGROUND: Staphylococcus aureus and Pseudomonas aeruginosa are common culture isolates in chronic rhinosinusitis (CRS). We aimed to determine whether they were associated with different clinical factors of CRS. METHODS: Adult CRS patients who underwent functional endoscopic sinus surgery (FESS) between October 1, 2007 and December 31, 2011 were recruited. Patient demographics, Lund-Mackay computed tomography (CT) scores, 22-item Sino-Nasal Outcome Test (SNOT-22) scores, disease characteristics, and medication use were collected prior to FESS. Intraoperative culture was obtained in a standard manner. We compared patients with isolates of S. aureus or P. aeruginosa to patients with other culture results and no bacterial growth, respectively. Multivariate logistic regression was performed. RESULTS: A total of 376 patients met criteria; 104 patients (28%) had S. aureus, 32 (9%) had P. aeruginosa, and 10 patients (3%) had no bacterial growth. After adjusting for all clinical factors, compared to patients with positive culture other than S. aureus, patients with S. aureus had 1.9 times increased odds of having nasal polyps (odds ratio [OR] = 1.9; 95% confidence interval [CI], 1.0 to 3.3; p = 0.036); when compared to patients with positive culture other than P. aeruginosa, patients with P. aeruginosa had 7.8 times increased odds of having prior FESS (OR = 7.8; 95% CI, 2.1 to 28.9; p = 0.002) (91% vs 58%; p < 0.001) and 3.6 times increased odds of having diabetes with marginal significance (OR = 3.6; 95% CI, 1.0 to 13.2; p = 0.053). The sample size in the no bacterial growth group was too small to draw firm conclusions. CONCLUSION: S. aureus was more common in CRS patients with nasal polyps, whereas P. aeruginosa was more common in CRS patients with prior FESS history and possibly diabetes.

Biofilm-forming bacteria and quality of life improvement after sinus surgery.

BACKGROUND: It remains unclear how much chronic rhinosinusitis (CRS) patients with bacterial biofilms can benefit from functional endoscopic sinus surgery (FESS). We aimed to evaluate whether biofilm-forming bacteria was associated with quality of life (QOL) improvement after FESS. METHODS: This retrospective cohort study included adult CRS patients who underwent FESS from 2008 to 2011. Sinus samples were taken to evaluate for biofilm-formation in vitro using a modified Calgary Biofilm Detection Assay. QOL was measured before FESS, and 1-month, 3-month, and 6-month after FESS using 22-item Sino-Nasal Outcome Test (SNOT-22) scores. Patients' characteristics and medications were collected. Clinical significant QOL change was defined as a difference of at least 0.5 standard deviation (SD) of baseline SNOT-22 score in the reference group. RESULTS: A total of 156 patients had complete data, and 15% had biofilm-forming bacteria (n = 24). Patients with biofilm-forming bacteria had significantly worse preoperative SNOT-22 scores compared to patients without biofilm-forming bacteria (48 ± 20 vs 38 ± 23, p = 0.048). Both groups had clinically significant QOL improvement after FESS, and the differences in their 1-month (23 ± 19 vs 17 ± 20) and 3-month (27 ± 18 vs 18 ± 19) post-FESS SNOT-22 scores were not significant. However, patients with biofilm-forming bacteria demonstrated significantly less QOL improvement than patients without biofilm-forming bacteria from pre-FESS to 6-month post-FESS visits after adjusting for clinical factors (35 ± 25 vs 14 ± 15; ß-coefficient = 0.71; 95% confidence interval [CI], 0.13 to 1.28; p = 0.016). CONCLUSION: CRS patients with biofilm-forming bacteria demonstrated clinically significant QOL improvement following FESS, but the degree of improvement was decreased overtime and became significantly worse than patients without biofilm-forming bacteria by 6-month follow-up. This QOL worsening was independent of other risk factors for CRS.