LPS decreases CFTR open probability and mucociliary transport through generation of reactive oxygen species.

Lipopolysaccharide (LPS) serves as the interface between gram-negative bacteria (GNB) and the innate immune response in respiratory epithelial cells (REC). Herein, we describe a novel biological role of LPS that permits GNB to persist in the respiratory tract through inducing CFTR and mucociliary dysfunction. LPS reduced cystic fibrosis transmembrane conductance regulater (CFTR)-mediated short-circuit current in mammalian REC in Ussing chambers and nearly abrogated CFTR single channel activity (defined as forskolin-activated Cl- currents) in patch clamp studies, effects of which were blocked with toll-like receptor (TLR)-4 inhibitor. Unitary conductance and single-channel amplitude of CFTR were unaffected, but open probability and number of active channels were markedly decreased. LPS increased cytoplasmic and mitochondrial reactive oxygen species resulting in CFTR carbonylation. All effects of exposure were eliminated when reduced glutathione was added in the medium along with LPS. Functional microanatomy parameters, including mucociliary transport, in human sinonasal epithelial cells in vitro were also decreased, but restored with co-incubation with glutathione or TLR-4 inhibitor. In vivo measurements, following application of LPS in the nasal cavities showed significant decreases in transepithelial Cl- secretion as measured by nasal potential difference (NPD) - an effect that was nullified with glutathione and TLR-4 inhibitor. These data provide definitive evidence that LPS-generated reactive intermediates downregulate CFTR function in vitro and in vivo which results in cystic fibrosis-type disease. Findings have implications for therapeutic approaches intent on stimulating Cl- secretion and/or reducing oxidative stress to decrease the sequelae of GNB airway colonization and infection.

Azithromycin and ciprofloxacin inhibit interleukin-8 secretion without disrupting human sinonasal epithelial integrity in vitro.

BACKGROUND: We recently developed a ciprofloxacin and azithromycin sinus stent (CASS) to target recalcitrant infections in chronic rhinosinusitis (CRS). The objective of this study was to evaluate the anti-inflammatory activity of azithromycin released from the CASS and assess the impact on the integrity and function of primary human sinonasal epithelial cells (HSNECs). METHODS: Pseudomonas aeruginosa lipopolysaccharide (LPS)-stimulated HSNECs were treated with azithromycin and/or ciprofloxacin at concentrations attainable from CASS release. Interleukin-8 (IL-8) secretion was quantified by enzyme-linked immunosorbent assay (ELISA). Epithelial integrity (transepithelial resistance [TEER], paracellular permeability [fluorescein isothiocyanate-labeled dextran], lactate dehydrogenase [LDH] assays) and function (ciliary beat frequency [CBF]) were also evaluated. RESULTS: Azithromycin significantly reduced secreted IL-8 from P. aeruginosa LPS-stimulated HSNECs at all concentrations tested (mean ± standard deviation; control = 5.77 ± 0.39 ng/mL, azithromycin [6 µg/mL] = 4.58 ± 0.40 ng/mL, azithromycin [60 µg/mL] = 4.31 ± 0.06, azithromycin [180 µg/mL] = 4.27 ± 0.26 ng/mL, p < 0.05). Co-incubation with azithromycin (6 µg/mL) and ciprofloxacin (2.4 µg/mL) in LPS-stimulated HSNECs also displayed a significant reduction in secreted IL-8 when compared to P. aeruginosa LPS alone (co-treatment = 4.61 ± 0.29 ng/mL, P. aeruginosa LPS = 7.35 ± 0.89 ng/mL, p < 0.01). The drugs did not negatively impact TEER, paracellular permeability, LDH release, or CBF, indicating retention of cell integrity and function. CONCLUSION: Azithromycin decreased P. aeruginosa LPS IL-8 production in HSNECs at drug concentrations attainable with sustained release of azithromycin from the CASS. In addition to antibacterial activity, anti-inflammatory properties of the CASS should provide further benefit for patients with recalcitrant CRS.

Treatment of Frontal Sinus Osteomyelitis in the Age of Endoscopy.

OBJECTIVE: Frontal sinus osteomyelitis is a severe complication which can result from chronic rhinosinusitis, trauma, or as a complication of reconstruction or obliteration of the frontal sinus. The objective of the current study is to evaluate the contemporary management of frontal sinus osteomyelitis in light of recent advancements in endoscopic surgical techniques. METHODS: Review of a prospectively collected database of patients with frontal sinus pathology was performed from 2008-2020. Data from individuals with frontal sinus osteomyelitis was collected including demographics, etiology, surgical technique, adjunctive medical treatments, complications, and clinical follow up. RESULTS: Sixteen patients (average age 48.3, range 8-84) were included in the study. An open approach was utilized in 6 patients (2 osteoplastic flaps, 3 Reidel procedures, 1 cranialization). Seven patients underwent completely endoscopic approaches (3 Draf IIB, 4 Draf III), while 3 individuals had combined procedures (Lynch with Draf III, osteoplastic flap + Draf III, fistula excision + Draf IIb). All patients received 6 weeks of antibiotics. Average clinical follow up was 24.4 months with no patients requiring revision procedures. CONCLUSION: Endoscopic, endoscopic-assisted, and open approaches were utilized successfully in the current series of patients with osteomyelitis of the anterior table of the frontal sinus. While the progression of endoscopic techniques allows an additional surgical treatment option, it is important to select patients appropriately as open procedures continue to have an important role in the treatment algorithm.

An Expedited Intracranial Pressure Monitoring Protocol Following Spontaneous CSF Leak Repair.

OBJECTIVE: Spontaneous cerebrospinal fluid (CSF) leaks represent a unique subset of skull base pathology and require distinctive management. Perioperative evaluation and management of intracranial hypertension are essential in preventing further erosion of the skull base and development of recurrent leak. The objective of this study is to evaluate the safety and utility of an expedited protocol for recording and managing intracranial hypertension following endoscopic repair of spontaneous CSF leaks. METHODS: Prospectively collected data was reviewed in patients undergoing endoscopic repair of spontaneous CSF leaks between January 2017 and March 2020. A standard intracranial pressure monitoring protocol was compared to an expedited protocol (EP), and data regarding the two groups was compared for leak location, short-term success of skull base repair, complications, hospital length of stay, and cost-based analysis. RESULTS: Fifty-five patients (standard protocol, n = 28 vs. EP, n = 27) were included in the study. Leak location was similar between cohorts, with the lateral recess being the most common locations in both groups (37.9% vs. 40.6%; P = .90). Postoperative complications (3.6% vs. 7.4%; P = .53) and ventriculoperitoneal shunt rate (32.1% vs. 22.2%; P = .41) were similar among cohorts. There was no difference in lumbar drain complications (0% vs. 7.4%; P = .14) or recurrent leak (7.1% vs. 0%; P = .16). Length of stay was shorter in the EP group [median(interquartile range): 3(1) vs. 2 (1); P < .01]. Total hospital charges were similar between groups (median (USD/$1,000): 83.57 ± 49.58 vs. 83.93 ± 46.11; P = .18). CONCLUSION: An expedited monitoring protocol shortened hospital stay without increased risk of complications. LEVEL OF EVIDENCE: III Laryngoscope, 131:E408-E412, 2021.

Antibiotic eluting sinus stents.

OBJECTIVES: Chronic rhinosinusitis (CRS) is a multifactorial disease affecting up to 16% of the United States population and disproportionately affecting the cystic fibrosis (CF) patient population. Despite treating the underlying infection, the use of systemic antibiotics has shown little efficacy in alleviation of symptom burden. This review seeks to discuss recent research on novel antibiotic eluting stent therapy in vitro and within animal models as well as the factors that contribute to its efficacy. DATA SOURCES: PubMed literature review. REVIEW METHODS: A review of all published literature related to antibiotic eluting sinus stents was conducted to integrate and summarize this innovative approach to chronic sinus infections. RESULTS: Placement of the ciprofloxacin sinus stent (CSS) and ciprofloxacin-ivacaftor sinus stent (CISS) exhibited improvement in endoscopic and radiographic findings in rabbit CRS models. While the CSS showed an overall trend toward improvement in microscopic findings and a reduction in biofilm mass, there remained a significant quantity of planktonic bacteria due to antibiotic depletion from an initial burst release in the first 48 hours of stent placement. The CISS and ciprofloxacin-azithromycin sinus stents (CASSs) exhibited controlled antibiotic release over the study period leading to greatly reduced planktonic bacterial load and biofilm mass. In vitro studies indicate that CASS may be just as efficacious at reducing biofilm mass. CONCLUSION: Antibiotic eluting sinus stents show significant promise as a novel therapeutic strategy for CRS. The CISS may have particular promise for the CF patient population by addressing both the infectious and genetic components of disease. Animal studies demonstrate significant promise for translation into human studies. Human clinical trials are warranted to determine the efficacy of antibiotic sinus stents in human patients. LEVEL OF EVIDENCE: NA.

Systematic review of anterior congenital cephaloceles: open vs endoscopic repair.

BACKGROUND: Anterior cephaloceles are rare congenital malformations that have historically been corrected via open approaches. Although the advent of endoscopic endonasal surgery has provided a minimally invasive and theoretically less morbid approach to the anterior skull base, whether endoscopic approaches provide superior treatment outcomes to open techniques has yet to be elucidated. The objective of this study was to systematically review the available literature regarding presentation and outcomes of open vs endoscopic repair of congenital anterior cephaloceles. METHODS: A systematic review of the PubMed, Embase, CINAHL, and Cochrane databases was performed on January 15, 2020, to identify studies from the past 50 years reporting cases of congenital anterior cephaloceles. Data on gender, age at operation, imaging modality, cephalocele location, operative approach, and intra- and postoperative complications were collected. RESULTS: Nonduplicated data (153 articles) consisted of 781 patients with congenital anterior encephaloceles. Surgical outcomes were reported in 349 patients (222 open approaches, 127 endoscopic approaches), with an average age of 4.6 years. There was a 1.3:1 male-to-female ratio. Clinical presentation included nasal obstruction (n = 154), hypertelorism (n = 106), and cleft lip/palate (n = 100). Defects were classified as sincipital (n = 479) or basal (n = 257), with 45 patients broadly classified as anterior. The number of complications experienced per operation was 0.13 for endoscopic and 0.44 for open approaches (p < 0.0001). Mortality was significantly lower for the endoscopic group compared with patients treated with open surgery (0.008 vs 0.05, p < 0.05). CONCLUSION: Endoscopic repair of congenital anterior cephaloceles resulted in decreased postoperative complications and mortality compared with open approaches. ©2020 ARSAAOA, LLC.

Contribution of Short Chain Fatty Acids to the Growth of Pseudomonas aeruginosa in Rhinosinusitis.

Background: Chronic rhinosinusitis (CRS) is characterized by complex bacterial infections with persistent inflammation. Based on our rabbit model of sinusitis, blockage of sinus ostia generated a shift in microbiota to a predominance of mucin degrading microbes (MDM) with acute inflammation at 2 weeks. This was followed by conversion to chronic sinus inflammation at 3 months with a robust increase in pathogenic bacteria (e.g., Pseudomonas). MDMs are known to produce acid metabolites [short chain fatty acids (SCFA)] that have the potential to stimulate pathogen growth by offering a carbon source to non-fermenting sinus pathogens (e.g., Pseudomonas). The objective of this study is to evaluate the concentrations of SCFA within the mucus and its contribution to the growth of P. aeruginosa. Methods: Healthy and sinusitis mucus from the rabbit model were collected and co-cultured with the PAO1 strain of P. aeruginosa for 72 h and colony forming units (CFUs) were determined with the targeted quantification of three SCFAs (acetate, propionate, butyrate). Quantification of SCFAs in healthy and sinusitis mucus from patients with P. aeruginosa was also performed via high performance liquid chromatography. Results: To provide evidence of fermentative activity, SCFAs were quantified within the mucus samples from rabbits with and without sinusitis. Acetate concentrations were significantly greater in sinusitis mucus compared to controls (4.13 ± 0.53 vs. 1.94 ± 0.44 mM, p < 0.01). After 72 h of co-culturing mucus samples with PAO1 in the presence of mucin medium, the blue-green pigment characteristic of Pseudomonas was observed throughout tubes containing sinusitis mucus. CFUs were higher in cultures containing mucus samples from sinusitis (8.4 × 109 ± 4.8 × 107) compared to control (1.4 × 109 ± 2.0 × 107) or no mucus (1.5 × 109 ± 2.1 × 107) (p < 0.0001). To provide evidence of fermentative activity in human CRS with P. aeruginosa, the presence of SCFAs in human mucus was analyzed and all SCFAs were significantly higher in CRS with P. aeruginosa compared to controls (p < 0.05). Conclusion: Given that SCFAs are solely derived from bacterial fermentation, our evidence suggests a critical role for mucin-degrading bacteria in generating carbon-source nutrients for pathogens. MDM may contribute to the development of recalcitrant CRS by degrading mucins, thus providing nutrients for potential pathogens like P. aeruginosa.

The SARS-CoV-2 pandemic impact on rhinology research: A survey of the American Rhinologic Society.

BACKGROUND: The COVID-19 pandemic has radically shifted healthcare operations within hospitals and universities across the globe. However, the effect of the COVID-19 pandemic on research endeavors and clinical trials is unclear. OBJECTIVE: This study investigates the impact of the COVID-19 pandemic on basic science and clinical research within the rhinology community. METHODS: A cross-sectional study was designed utilizing an 8-question survey to identify changes to rhinology research. Questions evaluated the impact of the COVID-19 pandemic on administrative research support and staffing, basic science research, clinical trials and resident research involvement. RESULTS: Seventy-one participants responded to the survey (8.5% response rate). Most respondents noted changes in IACUC/IRB approval (faster, 33%; slower, 31%). Of those who employed laboratory personnel, 64% were able to continue staff employment with full salary. The majority of animal research and in vitro studies were halted (64% and 56%, respectively), but animal care and cell line maintenance were allowed to continue. Clinical trial enrollment was most commonly limited to COVID derived studies (51%). Forty-seven percent of respondents noted increased resident research participation. CONCLUSION: The rapid spread of the SARS-CoV-2 virus has markedly impacted rhinology-related research. Maintaining safe workplace practices as restrictions are lifted will hopefully mitigate the spread of the virus and allow research productivity to resume.

Differential Chloride Secretory Capacity in Transepithelial Ion Transport Properties in Chronic Rhinosinusitis.

BACKGROUND: Epithelial ion transport regulates hydration of airway mucosal surfaces, and thus promotes effective mucociliary clearance (MCC). Decreased transepithelial Cl- transport may contribute to epithelial dysfunction by abrogating MCC and increasing mucus viscosity in chronic rhinosinusitis (CRS). The objective of the current study is to evaluate Cl- channel transport properties from cultures of human sinonasal epithelia. METHODS: Human sinonasal epithelia (HSNE) from patients undergoing sinus surgery were cultured at an air-liquid interface to confluence and full differentiation. The epithelial monolayers were mounted in Ussing Chambers to investigate pharmacological manipulation of ion transport. Epithelial Na+ channel (via Amiloride), CFTR (via forskolin), and Ca2+-activated Cl- channel (CaCC, via UTP) transport were investigated among three different patient groups: Control, CRS and CRS with polyposis. CFTR mRNA levels were evaluated with quantitative RT-PCR. RESULTS: HSNE cultures from 18 patients (Control = 9, CRS = 6, CRS with polyposis = 3) were evaluated in 142 experiments. Summary data from the 18 patients demonstrated that stimulated CFTR-mediated anion transport (Δ ISC) was significantly lower with CRS (7.58+/-2.24 µA/cm2) compared to control (25.86+/-3.44 µA/cm2) and CRS with polyposis (20.16+/-4.0 µA/cm2) (p = 0.004). No statistically significant difference was found for CaCC anion transport between groups (p = 0.39). Significantly decreased mRNA (relative expression) was noted in CRS cultures (CRS = 40.83+/-1.76 vs. control = 116.2+/-24.27, p = 0.03). CONCLUSIONS: A substantial decrease in the Cl- secretory capacity of HSNE monolayers was demonstrated in CRS subjects. Data suggest that CFTR may contribute more to abnormal ion transport in CRS than CaCC.

Phenotypes in Chronic Rhinosinusitis.

PURPOSE OF REVIEW: Chronic rhinosinusitis (CRS) is a heterogenous disease process affecting a significant proportion of the population and impacting quality of life and productivity. Historically, CRS has been classified broadly into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Increased understanding regarding unique presentations of CRS subsets and their underlying inflammatory profiles has led to a new system for classifying CRS phenotypes. RECENT FINDINGS: Consideration of CRS phenotypes has traditionally been a key factor in determining treatment paradigms. Under a new phenotype classification system, physical findings will continue to drive treatment decisions, but with more precision. Recent rapidly accumulated knowledge indicates that the broad categorization of CRSwNP or CRSsNP is no longer clinically useful. Reorganization of CRS phenotypes and their underlying endotypes will lead to more targeted and efficacious therapy.

Current management of congenital anterior cranial base encephaloceles.

OBJECTIVES: Congenital encephaloceles provide unique diagnostic and reconstructive challenges for the pediatric rhinologist. The objectives of the current study were to evaluate contemporary treatment strategies for congenital encephaloceles focusing on presentation, surgical technique, and outcomes. METHODS: Multi-institutional retrospective chart review of congenital encephaloceles (2003-2019). Data regarding demographics, presenting symptoms, associated abnormalities, surgical technique, size, location, and complications were collected. RESULTS: Fourteen patients with 15 congenital encephaloceles were treated using endoscopic techniques (avg 6.0 years, range 2 months-22 years) with mean follow up of 23 months. The majority presented with nasal obstruction (n = 13); only one child had cerebrospinal fluid (CSF) rhinorrhea. Associated anomalies included nasal deformities, congenital hypopituitarism, and Morning Glory syndrome. Average encephalocele size was 2.44 cm (range 0.5-3.6 cm) with mean skull base defect size of 8.6 x 7.7 mm. Locations included the foramen cecum (n = 9), central sphenoid (n = 3), midline anterior cranial fossa (n = 1), orbital plate of frontal bone (n = 1), and ethmoid roof (n = 1). Because of favorable expansion from encephaloceles, it was unnecessary to postpone surgeries to allow nasal cavity growth. Three individuals had prior operations, including surgeries for "nasal polyp" or "adenoid cyst". Two patients had post-operative complications (meningitis and CSF leak) effectively treated with no further sequelae. CONCLUSIONS: In the current study, congenital encephaloceles in children as young as 2 months were successfully repaired using endoscopic techniques. Endoscopic approaches remain a safe and effective intervention for management of these lesions.

In-vitro evaluation of a ciprofloxacin and azithromycin sinus stent for Pseudomonas aeruginosa biofilms.

BACKGROUND: Chronic rhinosinusitis (CRS) is a chronic inflammatory disease characterized by persistent inflammation and bacterial infection. Ciprofloxacin and azithromycin are commonly prescribed antibiotics for CRS, but the ability to provide targeted release in the sinuses could mitigate side effects and improve drug concentrations at the infected site. This study was aimed to evaluate the efficacy of the novel ciprofloxacin-azithromycin sinus stent (CASS) in vitro. METHODS: The CASS was created by coating ciprofloxacin (hydrophilic, inner layer) and azithromycin (hydrophobic, outer layer) onto a biodegradable poly-l-lactic acid (PLLA) stent. In-vitro evaluation included: (1) assessment of drug-coating stability within the stent using scanning electron microscopy (SEM); (2) determination of ciprofloxacin and azithromycin release kinetics; and (3) assessment of anti-biofilm activities against Pseudomonas aeruginosa. RESULTS: The ciprofloxacin nanoparticle suspension in the inner layer was confirmed by zeta potential. Both ciprofloxacin (60 µg) and azithromycin (3 mg) were uniformly coated on the surface of the PLLA stents. The CASS showed ciprofloxacin/azithromycin sustained release patterns, with 80.55 ± 11.61% of ciprofloxacin and 93.85 ± 6.9% of azithromycin released by 28 days. The CASS also significantly reduced P aeruginosa biofilm mass compared with bare stents and controls (relative optical density units at 590-nm optical density: CASS, 0.037 ± 0.006; bare stent, 0.911 ± 0.015; control, 1.000 ± 0.000; p < 0.001; n = 3). CONCLUSION: The CASS maintains a uniform coating and sustained delivery of ciprofloxacin and azithromycin, providing anti-biofilm activities against P aeruginosa. Further studies evaluating the efficacy of CASS in a preclinical model are planned.