Marcelo B. Antunes

Murine nasal septa for respiratory epithelial air-liquid interface cultures

Air-liquid interface models using murine tracheal respiratory epithelium have revolutionized the in vitro study of pulmonary diseases. This model is often impractical because of the small number of respiratory epithelial cells that can be isolated from the mouse trachea. We describe a simple technique to harvest the murine nasal septum and grow the epithelial cells in an air-liquid interface. The degree of ciliation of mouse trachea, nasal septum, and their respective cultured epithelium at an air-liquid interface were compared by scanning electron microscopy (SEM). Immunocytochemistry for type IV beta-tubulin and zona occludens-1 (Zo-1) are performed to determine differentiation and confluence, respectively. To rule out contamination with olfactory epithelium (OE), immunocytochemistry for olfactory marker protein (OMP) was performed. Transepithelial resistance and potential measurements were determined using a modified vertical Ussing chamber SEM reveals approximately 90% ciliated respiratory epithelium in the nasal septum as compared with 35% in the mouse trachea. The septal air-liquid interface culture demonstrates comparable ciliated respiratory epithelium to the nasal septum. Immunocytochemistry demonstrates an intact monolayer and diffuse differentiated ciliated epithelium. These cultures exhibit a transepithelial resistance and potential confirming a confluent monolayer with electrically active airway epitheliumn containing both a sodium-absorptive pathway and a chloride-secretory pathway. To increase the yield of respiratory epithelial cells harvested from mice, we have found the nasal septum is a superior source when compared with the trachea. The nasal septum increases the yield of respiratory epithelial cells up to 8-fold.

Mucociliary clearance : a critical upper airway host defense mechanism and methods of assessment

Purpose of review Mucociliary clearance is a critical host defense mechanism of the airways. Effective mucociliary clearance requires appropriate mucus production and coordinated ciliary activity. The important role of these two components is best demonstrated in disorders such as primary ciliary dyskinesia and cystic fibrosis, both of which lead to lifelong recurrent respiratory tract infections. We review the methods used to analyze mucociliary clearance. Recent findings Utilization of microdialysis probes has improved temporal resolution of mucociliary clearance in murine airways, availing many genetic mouse models to critical mucociliary clearance analysis, while improved fixation technique for transmission electron microscopy has allowed for detailed resolution of the airway surface liquid. High-speed digital video analysis has improved quantification of ciliary beat frequency while advancements in air–liquid interface culturing techniques have generated in-vitro models to investigate mucociliary clearance. Summary Advancements in techniques for analysis of mucociliary clearance have improved our understanding of the interaction between the respiratory epithelium and the airway surface liquid, resulting in the ability to study pathologic processes involving mucociliary clearance in great detail.

Epithelium, Cilia, and Mucus: Their Importance in Chronic Rhinosinusitis

Chronic rhinosinusitis is a common disease resulting from inflammation of the sinonasal mucosa. It has long been recognized that patients with chronic rhinosinusitis have impaired capacity to clear sinonasal secretions. However, the cause of this pathologic process is not well understood. In this article the components of mucociliary clearance, including cilia, mucus production, and cilia beat frequency, are reviewed and alterations of the system discussed regarding contribution to the disease process.

Radiographic and histologic analysis of the bone underlying inverted papillomas.

Introduction: Inverted papilloma (IP) is a benign but locally aggressive sinonasal tumor. Those localized to the maxillary sinus or medial maxillary wall have classically been removed through an external approach. In recent years, endoscopic removal has been advocated as an effective, minimally invasive approach. Successful endoscopic management is based on accurate intraoperative identification and complete resection of the tumor. The surgical management of the bone underlying the surface of an IP is less clearcut. Controversy exists as to whether the bony undersurface of an IP should be removed. In this article, histopathologic specimens and preoperative radiologic studies are prospectively examined to better understand the involvement of the bone underlying an inverted papilloma.

Murine tracheal and nasal septal epithelium for air-liquid interface cultures : A comparative study

Background Air–liquid interface cultures using murine tracheal respiratory epithelium have revolutionized the in vitro study of airway diseases. However, these cultures often are impractical because of the small number of respiratory epithelial cells that can be isolated from the mouse trachea. The ability to study ciliary physiology in vitro is of utmost importance in the research of chronic rhinosinusitis (CRS). Our hypothesis is that the murine nasal septum is a better source of ciliated respiratory epithelium to develop respiratory epithelial air–liquid interface models. Methods Nasal septa and tracheas were harvested from 10 BALB/c mice. The nasal septa were harvested by using a simple and straightforward novel technique. Scanning electron microscopy was performed on all specimens. Cell counts of ciliated respiratory epithelial cells were performed at one standard magnification (1535×). Comparative analysis of proximal and distal trachea, midanterior and midposterior nasal septal epithelium, was performed. Results Independent cell counts revealed highly significant differences in the proportion of cell populations (p < 0.00001). Ciliated cell counts for the trachea (106.9 ± 28) were an average of 38.7% of the total cell population. Nasal septal ciliated epithelial cells (277.5 ± 16) comprised 90.1% of the total cell population. Conclusion To increase the yield of respiratory epithelial cells harvested from mice, we have found that the nasal septum is a far superior source when compared with the trachea. The greater surface area and increased concentration of ciliated epithelial cells has the potential to provide an eightfold increase in epithelial cells for the development of air–liquid interface cultures.

Dose-dependent effects of topical tobramycin in an animal model of Pseudomonas sinusitis.

Background Topical antimicrobials are commonly used to treat Pseudomonas sinusitis after endoscopic sinus surgery. Despite their popularity, there is limited data in the literature to support its use. This study is the first to examine the effects of topical tobramycin in an animal model of Pseudomonas sinusitis. Methods Pseudomonas aeruginosa sinusitis was induced in the maxillary sinus of New Zealand white rabbits. Study groups received various concentrations of topical tobramycin instilled through a single lumen catheter embedded within the maxillary sinus for 7 consecutive days. A control group received normal saline irrigation. Bacterial counts were measured from the nasal lavage after irrigation. The sinonasal complex was analyzed and a histological grading system was used to score the degree of infection at study end. Results Nasal lavage bacterial counts of the saline control group remained persistently elevated throughout the study. Introduction of increasing concentrations of topical tobramycin caused the bacterial counts to fall to zero by study end. There was a dose-dependent histological response in which increasing concentrations of tobramycin led to a marked reduction but not total elimination of inflammation within the mucosa and underlying bone. Conclusion As opposed to normal saline irrigations, topical tobramycin led to a significant improvement in the degree of infection within an animal model of P. aeruginosa sinusitis. Despite the elimination of bacteria within the nasal lavage, there was a suggestion of a residual indolent infection as evidenced by persistent inflammation within the mucosa and underlying bone.

Reversal of chronic rhinosinusitis-associated sinonasal ciliary dysfunction.

Background Although multiple etiologies contribute to the development of chronic rhinosinusitis (CRS), a common pathophysiological sequelae is ineffective sinonasal mucociliary clearance, leading to stasis of sinonasal secretions, with subsequent infection and/or persistent inflammation. Proper therapeutic intervention typically restores mucociliary activity, suggesting that the pathophysiological process(es) responsible for CRS-associated mucostasis may be reversible. We previously demonstrated a blunted response of CRS sinonasal cilia after purinergic stimulation. This study investigated whether the blunted ciliary response is unique to purinergic stimulation and addressed whether the blunted effect is primarily caused by local CRS-associated mediators or inherent genetic defects in ciliary function. Methods A dual temperature-controlled perfusion chamber, differential interference contrast microscopy, and high-speed digital video were used to analyze both basal as well as cholinergic, adrenergic, and purinergic stimulation of cilia in human sinonasal mucosal explants. Additionally, enzymically dissociated sinonasal ciliated cells were maintained ex vivo in submersion, on glass coverslips, and assessed daily for purinergic ciliary beat frequency stimulation. Results Cholinergic and adrenergic stimulation generally were blunted in mucosal explants obtained from CRS patients. Ex vivo maintenance of samples demonstrated that the majority of CRS samples developed a stimulatory phenotype within 36 hours of culturing. Conclusion CRS is a common debilitating disease principally affecting sinonasal epithelial function with a resultant diminution of mucociliary transport. Presently, little is known about how this disease process affects the sinonasal epithelial ciliated cells. Our data suggest that ciliary response to environmental insults is blunted in a reversible manner in CRS patients.

Transient receptor potential vanilloid type 4 channel expression in chronic rhinosinusitis

Background Transient receptor potential (TRP) channels are a novel class of nonvoltage gated membrane cation channels that can be activated by mechanical stimulation and temperature change. Recently, TRP vanilloid type 4 (TRPV4) has been implicated in detecting viscosity changes in fallopian tube epithelial cells and inducing a compensatory response in ciliary activity and, as such, represents a possible molecular trigger for modulating respiratory ciliary activity. Thus, the goal of this study was to establish the expression pattern of TRPV4 in human sinonasal mucosa and determine whether expression is altered in chronic rhinosinusitis (CRS). Methods Sinus mucosal biopsy specimens were obtained from patients with CRS, CRS with nasal polyps (NPs), and healthy controls. TRPV4 mRNA and protein expression were confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) and immunoblot analysis, respectively. TRPV4 gene expression was measured next using quantitative RT-PCR. Immunofluorescence was performed on sinus mucosal explants and respiratory epithelial air–liquid interface cultures to localize cellular expression. Results TRPV4 mRNA and protein were expressed in all samples. There was a statistically significant increase (p < 0.05) in TRPV4 gene expression in nonpolypoid CRS patients, but no difference in CRS with NP. Dual label immunofluorescence showed TRPV4 expression to be mutually exclusive of ciliated cells. Conclusion Although TRPV4 represents an ideal molecular trigger for ciliary modulation, absent expression of the channel in ciliated cells precludes this function. However, altered expression of the channel in CRS and presumed expression of TRPV4 in secretory cells of the mucosa indicate a potential role in mucus homeostasis and CRS pathogenesis.

Injectable fillers for volume replacement in the aging face.

In recent years, there has been a better understanding of the aging process. In addition to changes occurring in the skin envelope, significant changes occur in the subcutaneous fat and craniofacial skeleton. This has led to a paradigm shift in the therapeutic approach to facial rejuvenation. Along with soft tissue repositioning, volumizing the aging face has been found to optimize the result and achieve a more natural appearance. Early in the aging process, when there has not been a significant change to the face requiring surgical intervention, fillers alone can provide minimally invasive facial rejuvenation through volumizing. Multiple injectable soft tissue fillers and biostimulators are currently available to provide facial volume such as hyaluronic acid, calcium hydroxylapatite, poly-L-lactic acid, polymethyl methacrylate, and silicone. A discussion of the morphological changes seen in the aging face, the properties of these products, and key technical concepts will be highlighted to permit optimum results when performing facial volumizing of the upper, middle, and lower thirds of the face. These fillers can act as a dress rehearsal for these patients considering structural fat grafting.

Physiologic alterations in the murine model after nasal fungal antigenic exposure

Objective To determine whether a recently developed murine model of fungus-induced sinonasal inflammation demonstrated alterations in ciliary activity and expression of inflammatory cytokines. Study Design A prospective randomized controlled study of rhinosinusitis after fungal antigenic sensitization was performed with intraperitoneal aspergillus antigen injection followed by intranasal antigen challenge for 4 weeks. Saline solution was used in a parallel fashion for control animals. Subjects and Methods Six mice were used to validate the model. Additional 15 mice were used for ciliary beat frequency (CBF) analysis and cytokine expression with multiplex technology. Mean values for degree of inflammation, secretory hyperplasia, CBF, and cytokine expression were compared. Results Histologic analyses demonstrated dense chronic inflammation in aspergillus-challenged animals versus sparse inflammatory cells in controls. Significant differences in mean of aspergillus-challenged versus control animals were observed in degree of inflammation (P < 0.01), secretory hyperplasia (P < 0.01), CBF (P < 0.00002), IL-1α (P < 0.0002), IL-1β (P < 0.0003), IL-4 (P < 0.02), TNF-α (P < 0.02), and RANTES (P < 0.01). Conclusion Alteration in baseline CBF accompanied by increased expression of specific inflammatory cytokines was observed in aspergillus-challenged mice.