Michael A. Kohanski

Bactericidal antibiotics promote reactive oxygen species formation and inflammation in human sinonasal epithelial cells.

Bactericidal antibiotics have been shown to stimulate reactive oxygen species (ROS) formation in mammalian cells through mitochondrial dysfunction. This results in oxidative tissue damage that may have negative consequences for long‐term antibiotic use. Antibiotics are widely and heavily used in the treatment of acute and chronic sinusitis; however, the relationship between antibiotics and ROS formation in sinonasal epithelial cells (SNECs) has not yet been demonstrated.

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.

Relative susceptibility of airway organisms to antimicrobial effects of nitric oxide

Nitric oxide (NO) is released in the airway as a critical component of innate immune defense against invading pathogenic organisms. It is well documented that bacteriostatic and bactericidal effects of NO are concentration‐dependent. However, few data exist comparing relative susceptibility of common pathogens to NO at physiologic concentrations. In this study we evaluated the effects of NO on 4 common airway bacteria and 1 fungus, and examined the potential implications of discrepancies in sensitivity.

Sinonasal Epithelial Cell Response to Staphylococcus aureus Burden in Chronic Rhinosinusitis

IMPORTANCE Chronic rhinosinusitis (CRS) is an inflammatory disorder of the nose and paranasal sinuses. Staphylococcus aureus is increasingly linked with CRS exacerbations. Little is known about how bacteria activate inflammatory pathways that contribute to CRS. OBJECTIVE To develop an in vitro coculture system to explore how infection with S aureus stimulates innate immune responses of sinonasal epithelial cells (SNECs). DESIGN, SETTING, AND PARTICIPANTS Sinonasal epithelial cells were collected from 13 patients during endoscopic sinus surgery and grown in culture at the air-liquid interface from July 2014 through December 2014. INTERVENTIONS Differentiated SNECs from control individuals, patients with CRS with nasal polyps (CRSwNPs), and patients with CRS without nasal polyps (CRSsNPs) were infected with S aureus at 3 different concentrations for 24 hours. MAIN OUTCOMES AND MEASURES Growth of S aureus and viability of SNECs were measured. Expression of inflammatory markers and innate immune genes was measured by reverse transcription-polymerase chain reaction. Basal secretion of interleukin 8 was determined by enzyme-linked immunosorbent assay. RESULTS Cultured SNECs from patients with CRSsNPs demonstrated a significant increase (P < .05) in expression of interleukin 8 (23-fold to 82-fold) and tumor necrosis factor (11-fold to 61-fold) at all the tested concentrations of S aureus. Control or CRSwNP SNECs demonstrated a significant increase (P < .05) in expression of interleukin 8 (47-fold and 50-fold, respectively) and tumor necrosis factor (106-fold and 58-fold, respectively) at the higher inoculum of S aureus. Basal secretion of inflammatory markers correlated with expression changes. No significant changes in expression were observed for the helper T cell, subtype 2, inflammatory mediators tested. CONCLUSIONS AND RELEVANCE In this study, we developed a model to study early innate immune-mediated changes in SNECs cocultured at an air-liquid interface with bacteria. We also demonstrated that bacterial burden can be detected by SNECs in the absence of adaptive immune-mediated responses. The CRSsNP SNECs are more sensitive to S aureus burden than control or CRSwNP SNECs. Future studies will further develop this infection model and explore the SNEC innate immune response to bacteria.

The Role of Quinine-Responsive Taste Receptor Family 2 in Airway Immune Defense and Chronic Rhinosinusitis

Background Bitter (T2R) and sweet (T1R) taste receptors in the airway are important in innate immune defense, and variations in taste receptor functionality in one T2R (T2R38) correlate with disease status and disease severity in chronic rhinosinusitis (CRS). Quinine is a bitter compound that is an agonist for several T2Rs also expressed on sinonasal cells, but not for T2R38. Because of this property, quinine may stimulate innate immune defense mechanisms in the airway, and functional differences in quinine perception may be reflective of disease status in CRS. Methods Demographic and taste intensity data were collected prospectively from CRS patients and non-CRS control subjects. Sinonasal tissue from patients undergoing rhinologic surgery was also collected and grown at an air–liquid interface (ALI). Nitric oxide (NO) production and dynamic regulation of ciliary beat frequency in response to quinine stimulation were assessed in vitro. Results Quinine reliably increased ciliary beat frequency and NO production in ALI cultures in a manner consistent with T2R activation (p < 0.01). Quinine taste intensity rating was performed in 328 CRS patients and 287 control subjects demonstrating that CRS with nasal polyps (CRSwNP) patients rated quinine as significantly less intense than did control subjects. Conclusion Quinine stimulates airway innate immune defenses by increasing ciliary beat frequency and stimulating NO production in a manner fitting with T2R activation. Patient variability in quinine sensitivity is observed in taste intensity ratings, and gustatory quinine “insensitivity” is associated with CRSwNP status. Thus, taste tests for quinine may be a biomarker for CRSwNP, and topical quinine has therapeutic potential as a stimulant of innate defenses.

Solitary chemosensory cells producing interleukin-25 and group-2 innate lymphoid cells are enriched in chronic rhinosinusitis with nasal polyps: Solitary chemosensory cells and ILC2s in CRSwNP

Chronic rhinosinusitis with nasal polyps (CRSwNP) is commonly characterized by type‐2 inflammation. It is established that group‐2 innate lymphoid cells (ILC2s) are a subset of immune cells important in orchestrating mucosal type‐2 response. IL‐25 is an epithelial‐derived cytokine that is a critical activator of ILC2s. Recent evidence demonstrates that specialized taster epithelial cells, such as solitary chemosensory cells (SCCs), may be producers of IL‐25. To elucidate the relationship between SCCs and ILC2s in CRSwNP, we sought to quantify ILC2s and SCCs to determine if these cell types are enriched in nasal polyps compared to healthy sinonasal mucosa.

Bactericidal antibiotics promote oxidative damage and programmed cell death in sinonasal epithelial cells

Antibiotics are widely and heavily used in the treatment of chronic sinusitis. Bactericidal antibiotics can stimulate reactive oxygen species (ROS) formation, a proinflammatory response, and cell death in cultured human sinonasal epithelial cells (SNECs). Sulforaphane (SFN) is a potent stimulator of the antioxidant nuclear factor erythroid 2‐related factor 2 (Nrf‐2) system and a suppressor of inflammation. In this study we utilized SFN to further explore the relationship between levofloxacin treatment, ROS formation, and the cell death response.

Evolution in the surgical management of chronic rhinosinusitis: Current indications and pitfalls

&NA; Chronic rhinosinusitis (CRS) consists of a range of inflammatory conditions in the sinuses that can result in clinical symptoms. The underlying pathophysiology and its relationship to lower airway disease are complex. Current definitions of CRS can serve more as an indication for potential surgical intervention rather than a marker of disease state. CRS can be asymptomatic and may require medical management to avoid disease progression and minimize the risk of lower airway disease. Endoscopic surgery has undergone a significant evolution and refinement, but the most common surgical complication remains persistent inflammation and disease recurrence. It is important to recognize that surgery alone rarely cures CRS and patients require long‐term medical therapy for continued asymptomatic inflammation. Careful postoperative care and endoscopic follow‐up to ensure resolution of inflammation are key to ensuring optimal surgical outcomes and reduce the risk of revision surgery. Future work on CRS endotypes will allow discovery of new therapies to treat CRS, as well as refine indications for medical or surgical intervention and postoperative care.

Effects of ophthalmologic solutions on sinonasal ciliated epithelium

Off‐label use of topical ophthalmologic formulations for treatment of rhinologic disease is cited in recent literature and is anecdotally prevalent among practicing otolaryngologists. Steroids, antibiotics, and other drugs designed for ocular use have subjective clinical efficacy in the nose and sinuses, but their specific effects on the ciliated epithelium are less well defined. This study examines 9 commercially available ophthalmologic drug formulations for effects on ciliary motility in sinonasal cultures, in an effort to characterize their utility as topical therapies for sinonasal diseases.

Sentinels at the wall: epithelial-derived cytokines serve as triggers of upper airway type 2 inflammation: Epithelial cytokines in upper airway

Recent evidence has demonstrated an expanding role of respiratory epithelial cells in immune surveillance and modulation. Studies have been focusing on the earliest events that link epithelial injury to downstream inflammatory responses. Cytokines produced by and released from respiratory epithelial cells are among these early trigger signals. Epithelial‐derived cytokines, namely thymic stromal lymphopoietin (TSLP), interleukin (IL)‐25, and IL‐33, have come to the forefront of recent investigations. Each of these 3 cytokines has been implicated in chronic rhinosinusitis (CRS), asthma, and atopy. Herein we review studies elucidating the roles of epithelial‐derived cytokines in the pathobiology of upper airway disease, with particular emphasis on type 2 inflammatory conditions.