Nasal Polyposis: More than a Chronic Inflammatory Disorder-A Disease of Mechanical Dysfunction-The São Paulo Position

Differential Angiogenic Induction Impacts Nasal Polyp Tissue Growth

In chronic rhinosinusitis with nasal polyps, inflammatory edema drives tissue remodeling favoring anomalous growth of the nasal mucosa, but a proangiogenic contribution of nasal polyp in support of tissue growth is still controversial. The chorioallantoic membrane of chicken embryo model was employed to address the potentiality of nasal tissue fragments to modulate angiogenesis. Fifty-seven fertilized eggs were implanted with polyp or healthy nasal mucosa tissue or were kept as non-implanted controls. The embryos' size, length, and development stage, and chorioallantoic membrane vasculature morphology were evaluated after 48 h. Quantitative computer vision techniques applied to digital chorioallantoic membrane images automatically calculated the branching index as the ratio between the areas of the convex polygon surrounding the vascular tree and the vessels' area. Ethics approval and consent to participate: the study was approved by the Human Research Ethics Committee of the Federal University of São Paulo (CAAE number: 80763117.1.0000.5505) and by the Animal Research Ethics Committee of University of São Paulo (nº CEUA 602-2019). Mucosal, but not polyp tissue implants, hampered embryo development and induced underdeveloped chorioallantoic membranes with anastomosed, interrupted, and regressive vessels. Vessels' areas and branching indexes were higher among the chorioallantoic membranes with polyp implants and controls than among those with healthy mucosa implants. Nasal polyp presents differential angiogenic induction that impacts tissue growth.

MORPHOLOGICAL FEATURES OF MAXILLARY SINUS CYSTS BASED ON THE STUDY OF PARTICULAR HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL FACTORS OF INFLAMMATION

OBJECTIVE

The aim: To study the morphological structure and immunohistochemical markers of inflammatory cells in the maxillary sinus cyst wall.

PATIENTS AND METHODS

Materials and methods: Biopsy samples of maxillary sinus cysts of 92 operated patients aged 18 to 74 years were studied. We used standard staining with hematoxylin and eosin, PAS reaction, and immunohistochemical analysis with monoclonal antibodies to CD68 (macrophages) and CD3 (T- lymphocytes) to determine morphological features and severity of inflammation and PanCK AE1/AE2 antibodies to identify epithelium state.

RESULTS

Results: All patients were divided into 2 groups: 29 patients with retention cysts and 63 with lymphagiotatic cysts (pseudocysts), depending on the unilateral or bilateral epithelial lining of the cyst wall. Retention cysts had the bilateral epithelial lining with a saving its function and structure. The thinned connective tissue layer was filled with separate clusters of lymphocytes and macrophages. Lymphagiotatic cysts were characterized by the unilateral epithelium lining of the wall with signs of degeneration, desquamation, and loss of the mucus-forming function. Dense infiltration of the connective tissue layer by inflammatory cells with pronounced expression is observed.

CONCLUSION

Conclusions: Immunohistochemical analysis with monoclonal antibodies to CD3 and CD68 demonstrated that the inflammatory infiltrate of pseudocysts is represented by T-lymphocytes and different sizes of macrophages. The inflammatory infiltration of the pseudocyst wall was significantly severe compared to retention cysts.

Three-dimensional cell culture for the study of nasal polyps

OBJECTIVES

Three-dimensional (3D) cell cultures have many applications such as stem cell biology research, new drug discovery, cancer, and Chronic Rhinosinusitis with Nasal Polyps (CRSwNP). This disease is characterized by a significant impact on quality of life and productivity. The diversity of factors that act in the progression of CRSwNP point to the creation of a cell culture model that allows the integration of different cell types with extracellular matrix. This work aimed to create a cell culture model in 3 dimensions (spheroids) for the study of Nasal Polyposis.

METHODS

Nasal polyp tissue from patients diagnosed with CRSwNP was mechanically dissociated using tweezers and a scalpel and the solution containing cells and small aggregates of nasal polyps was transferred to a Petri dish containing 5 mL of culture medium at the concentration of 10⁶ cells/mL.

RESULTS

The spheroids were cultivated for 20 days, fixed and analyzed using confocal microscopy. In a 3D culture environment, the spheroids were formed both by clustering cells and from small tissue fragments. In the cultures analyzed, the ciliary beat was present from the dissociation of the cells up to 20 days in culture.

CONCLUSION

Our findings also point to these characteristics showing the environment generated in our study, the cells remained differentiated for a longer time and with ciliary beating. Thus, this work shows that nasal polyp-derived cells can be maintained in a 3D environment, enabling better strategies for understanding CRSwNP in situations similar to those found in vivo.

LEVEL OF EVIDENCE

Laboratory studies.

Decreased CFTR/PPARγ and increased transglutaminase 2 in nasal polyps

OBJECTIVE

Transglutaminase (TGM)2 and peroxisome proliferator-activated receptor (PPAR)γ are thought to participate in the pathogenesis of nasal polyp formation in cystic fibrosis (CF). We herein investigated expressions of cystic fibrosis transmembrane conductance regulator (CFTR), TGM2, PPARγ and isopeptide bonds, a reaction product of TGM, in non-CF nasal polyps.

METHODS

Nasal polyps and inferior turbinates were collected from chronic rhinosinusitis patients without CF during transnasal endoscopic sinonasal surgery. Expressions of CFTR, TGM2, isopeptide bonds and PPARγ were examined by fluorescence immunohistochemistry and quantitative RT-PCR. Expression of CFTR was also analyzed by Western blot.

RESULTS

Immunohistochemical fluorescence of the nasal polyp was significantly lower for CFTR and PPARγ, and significantly higher for TGM2 and isopeptide bonds than that of the turbinate mucosa. Lower expression of CFTR in the nasal polyp than in the turbinate mucosa was also observed in Western blot. Expression of PPARG mRNA was significantly lower in the nasal polyp than in the turbinate mucosa, whereas expressions of CFTR mRNA or TGM2 mRNA did not differ between the two tissues. Immunohistochemical fluorescence for CFTR showed significant negative correlation with that for TGM2 and isopeptide bonds, and significant positive correlation with that for PPARγ. The fluorescence for TGM2 was positively correlated with that for isopeptide bonds and negatively correlated with that for PPARγ. The fluorescence for isopeptide bonds tended to be negatively correlated with that for PPARγ.

CONCLUSIONS

These results suggest a possible role of the CFTR-TGM2-PPARγ cascade in the pathogenesis of nasal polyp formation in non-CF patients as in CF patients.

Structural changes in the extracellular matrix after cross-linking of nasal polyp tissue

Chronic rhinosinusitis with nasal polyposis is a disease characterised by a mechanical dysfunction that facilitates anomalous growth of the nasal mucosa, due to its unique remodelling process. The development of procedures capable of interfering with this process is thus of the utmost importance. This study deals with the evaluation of the effects of cross-linking upon the nasal polyp tissue extracellular matrix. Six patients undergoing surgery for polypectomy were selected. The riboflavin/UVA collagen cross-linking technique was applied to the surface of epithelialised and de-epithelialised resected polyps of the intervention group. The control group polyps were not submitted to cross-linking procedures. Ultrathin polyp tissue sections (8 μm) were processed for immunofluorescence with mouse anti-type I collagen antibody and AlexaFluor 488 conjugated secondary antibody plus DAPI counterstaining, and analysed by confocal microscopy. The effect of riboflavin/UVA collagen cross-linking was visible on confocal fluorescence microscopy. Quantitative morphology was associated with fluorescence imaging analysis, and pixel density and brightness were evaluated. The surface of treated polyps exhibited a higher density of collagen fibres compared to control polyps, as could be observed both visually and through objective measurements of the fluorescent regions. The effect was enhanced on the surface of the de-epithelialised polyps. The higher density of collagen fibres exhibited by the de-epithelialised treated polyps demonstrates the feasibility of this technique in interfering with the remodelling process and the mechanical dysfunction found in chronic rhinosinusitis with nasal polyposis.

Effect of lipopolysaccharide and polyinosinic:polycytidylic acid in a murine model of nasal polyp

Several factors, including bacterial and viral infections, have been associated with rhinosinusitis and nasal tissue remodelling that may result in nasal polyp formation. However, the potential role of bacterial or viral stimuli triggering polyp development is unclear. Here, we used lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid [poly(I:C)] in a murine model of allergic rhinosinusitis to compare different effects of bacterial- and virus-derived stimuli in the pathogenesis of nasal polyp formation. Briefly, BALB/c mice were sensitised and challenged with ovalbumin and staphylococcal enterotoxin, with or without LPS or poly(I:C), and the consequent histopathological profiles, cytokines, and systemic humoral responses were studied. While no significant differences in polyp formations and epithelial disruptions were observed among the experimental groups, the local cell recruitment patterns slightly differed in animals that received either LPS or poly(I:C). Additionally, the local immune environments generated by LPS or poly(I:C) stimulation varied. LPS stimulation induced a marked Th1/Th17 response and predominantly neutrophilic nasal polyp formations, whereas poly(I:C) induced a Th2-skewed environment in neutrophilic nasal polyp development. Overall, our findings show that both cell recruitment patterns and local immune environments induced by these two stimuli differ, which may have implications in the physiopathology of rhinosinusitis with nasal polyp.

Montelukast Has no Impact on the Systemic Production of TGFβ-1 in Patients with Nasal Polyposis Associated with Aspirin Intolerance

Introduction  Nasal polyposis is a disease characterized by a mechanical dysfunction of the nasal mucosa, closely related to the unique makeup of its extracellular matrix, which develops as the result of an anomalous tissue remodeling process.

Transforming growth factor beta 1 (TGF-β1) is reduced not only in the nasal polypoid tissue, but also in the plasma of aspirin-intolerant patients. These patients exhibit an imbalance in the production of eicosanoids characterized by an increase in leukotrienes. Thus, it is important that the relationship between the production of leukotrienes and TGF-β1 be assessed.

Objective  To evaluate the effects of the cysteinyl leukotriene (CysLT) receptor antagonist montelukast on the systemic production of TGF-β1 in patients with nasal polyposis, with or without concomitant aspirin intolerance.

Methods  The sample comprised 48 individuals with diagnosis of nasal polyposis and 15 healthy controls for comparison of the baseline TGF-β1 levels in the peripheral blood and after treatment with CysLT receptor antagonist montelukast in the nasal-polyposis group.

Results  There was no difference in the change in TGF-β1 levels after the treatment with montelukast in the subgroup of patients with polyposis and asthma ( p  = 0.82) and in the subgroup with polyposis, asthma, and aspirin intolerance ( p  = 0.51).

Conclusion  we found no impact of the therapy with a leukotriene receptor blocker on the production of TGF-β1, making the antileukotriene therapy a highly questionable choice for the treatment of nasal polyposis, particularly from the standpoint of seeking to modify the remodeling process in this disease.

Expression of Cl- channels/transporters in nasal polyps

PURPOSE

Nasal polyp formation is a common sequela of prolonged chronic rhinosinusitis, but the mechanism underlying this disease state is still controversial. We compared the expressions of Cl^- channels/transporters in nasal polyps with those in inferior turbinates to explore whether a deficiency in Cl^- transport may participate in the pathophysiology of nasal polyp formation as in patients with cystic fibrosis.

METHODS

Nasal polyps and inferior turbinates were collected from 12 chronic rhinosinusitis patients with hypertrophic rhinitis and/or nasal polyps. Expressions of cystic fibrosis transmembrane conductance regulator (CFTR), pendrin, Na⁺-K⁺-2Cl^- cotransporter 1 (NKCC1), SLC26A3, TMEM16A and anion exchanger 2 (AE2) were examined by fluorescence immunohistochemistry using Alexa Fluor 488.

RESULTS

CFTR was weakly expressed on the epithelial surface of the turbinate mucosa whereas the nasal polyps showed almost no fluorescence. Pendrin was mainly expressed on the epithelial surface in both tissues. The fluorescence was moderate in the nasal polyps and strong in the turbinate mucosa. For NKCC1, moderate fluorescence was observed throughout the entire epithelial layer of the nasal polyps, but the turbinate mucosa exhibited almost no fluorescence. On the other hand, no fluorescence for SLC26A3, TMEM16A or AE2 was seen in either tissue.

CONCLUSION

These results suggest that CFTR, pendrin and NKCC1 may participate in the pathogenesis of nasal mucosal edema and play roles in the mechanism of nasal polyp formation.

Alterations in cellular force parameters and cell projections in Nasal polyps-derived fibroblasts

OBJECTIVE

Chronic Rhinosinusitis with Nasal Polyps (CRSwNP) is a disease that features a mechanical dysfunction involving chronic inflammation and altered tissue remodeling. In this study, we aim to evaluate the fibroblast morphology and its cellular traction force in primary fibroblasts cell cultures obtained from both healthy individuals (n=7) and patients with CRSwNP (n=8).

METHODS

Using a Traction-force Microscopy we analyzed parameters of Force/Tension in fibroblasts cultures in both experimental groups.

RESULTS

The analysis of the Projected Area of Cell revealed that fibroblasts derived from nasal mucosa of healthy individuals have an area on average 39.24% larger than the fibroblasts obtained from the nasal polyp tissue. We also observed that the parameters directly related to the force of the cell, Max Cumulative Force and Net Contractile Moment, presented a high Force/Tension per unit of area in the fibroblasts derived from the healthy nasal mucosa (on average 41% and 52.54% higher than the fibroblasts of the nasal polyp respectively).

CONCLUSION

Our results demonstrate a cellular mechanism that may be associated with the mechanical dysfunction found in the Nasal Polyp tissue. The weak traction force of nasal polyp-derived fibroblast may, in lower dimensions, impact on the remodeling of nasal mucosa in CRSwNP.