Hypoxia induces cysteine-rich 61, vascular endothelial growth factor, and interleukin-8 expressions in human nasal polyp fibroblasts: An implication of neutrophils in the pathogenesis of nasal polyposis

In-droplet multiplex immunoassays for hypoxia-induced single-cell cytokines

Cytokine expression is an important biomarker in understanding hypoxia microenvironments in tumor growth and metastasis. In-droplet-based immunoassays performed above the target cell membrane were employed to track the cytokines of single cells with the aid of three types of immuno-nanoprobes (one capture nanoprobe and two reporter nanoprobes). Single cells and nanoprobes were co-packaged in water-in-oil microdroplets (about 100 μm in diameter) using a cross-shaped microfluidic chip. In each droplet, capture nanoprobes would be first fixed to the cell surface by linking to membrane proteins that have been streptavidinized. Then, the capture nanoprobes can collect cell-secreted cytokines (VEGF and IL-8) by the antibodies, followed by two reporter nanoprobes that emit distinguishable fluorescence. Fluorescence imaging was utilized to record the signal outputs of two reporter probes, which reflect cytokine expressions secreted by a single tumor cell. The cytokine levels at different degrees of hypoxia induction were assessed. Multiple chemometric methods were adopted to distinguish differences in the secretion of two cytokines and the results demonstrated a positive correlation. This study developed an in-droplet, dual-target, simultaneous biosensing strategy for a single cell, which is helpful for understanding the impacts of hypoxia microenvironments on cell cytokines that are vital for assessing early cancer diagnosis and prognosis.

Role of Fibroblasts in Chronic Inflammatory Signalling in Chronic Rhinosinusitis with Nasal Polyps-A Systematic Review

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an inflammatory disease of the nose and paranasal sinuses characterized by the presence of nasal polyps. The symptoms produced by the presence of nasal polyps such as nasal obstruction, nasal discharge, facial pain, headache, and loss of smell cause a worsening in the quality of life of patients. The source of the nasal polyps remains unclear, although it seems to be due to a chronic inflammation process in the sinonasal mucosa. Fibroblasts, the main cells in connective tissue, are intimately involved in the inflammation processes of various diseases; to this end, we carried out a systematic review to evaluate their inflammatory role in nasal polyps. Thus, we evaluated the main cytokines produced by nasal polyp-derived fibroblasts (NPDF) to assess their involvement in the production of nasal polyps and their involvement in different inflammatory pathways. The results of the review highlight the inflammatory role of NPDF through the secretion of various cytokines involved in the T1, T2, and T3 inflammatory pathways, as well as the ability of NPDF to be stimulated by a multitude of substances. With these findings, the fibroblast is positioned as a new potential therapeutic target in the treatment of CRSwNP.

The role of hypoxia in the pathophysiology of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the nasal cavity characterized by excessive nasal mucus secretion and nasal congestion. The development of CRS is related to pathological mechanisms induced by hypoxia. Under hypoxic conditions, the stable expression of both Hypoxia inducible factor-1 (HIF-1) α and HIF-2α are involved in the immune response and inflammatory pathways of CRS. The imbalance in the composition of nasal microbiota may affect the hypoxic state of CRS and perpetuate existing inflammation. Hypoxia affects the differentiation of nasal epithelial cells such as ciliated cells and goblet cells, induces fibroblast proliferation, and leads to epithelial-mesenchymal transition (EMT) and tissue remodeling. Hypoxia also affects the proliferation and differentiation of macrophages, eosinophils, basophils, and mast cells in sinonasal mucosa, and thus influences the inflammatory state of CRS by regulating T cells and B cells. Given the multifactorial nature in which HIF is linked to CRS, this study aims to elucidate the effect of hypoxia on the pathogenic mechanisms of CRS.

Transcriptome sequencing reveals altered ciliogenesis under hypoxia in nasal epithelial cells from chronic rhinosinusitis with nasal polyps

Background

Hypoxia is considered a key factor in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). However, the specific mechanism driving polypogenesis under hypoxic conditions is unclear. This study aimed to explore hypoxia-induced alterations in the transcriptome of human nasal epithelial cells (HNECs) in vitro.

Methods

HNECs derived from the tissue of patients with CRSwNP were established as air-liquid interface (ALI) cultures. Confluent cultures were kept submerged or treated with cobalt chloride (CoCl2) to induce hypoxia. Transcriptome analysis was used to identify key mRNAs involved in this process. Real-time PCR (RT-PCR), Western blotting, and immunofluorescence were used to observe the effects of hypoxia on ciliogenesis.

Results

Numerous genes, biological processes and pathways were altered under submerged culture conditions or after CoCl2 treatment. Analysis of the results under both hypoxic conditions revealed that the transcriptional program responsible for ciliogenesis was significantly impaired. Downregulation of cilia-related genes and inhibition of ciliated cell differentiation under hypoxia were confirmed by RT-PCR, Western blot and immunofluorescence analyses.

Conclusion

Hypoxia impairs ciliogenesis and ciliary function in HNECs, which might play a role in the pathogenesis of CRSwNP.

Hypoxia-Induced Cyr61/CCN1 Production in Infantile Hemangioma

BACKGROUND

Hypoxia may play a role in the pathogenesis of infantile hemangioma. Cysteine-rich angiogenic inducer 61 (Cyr61), or CCN1, can be induced under hypoxic conditions in several types of cells. However, whether CCN1 has any impact on infantile hemangioma remains unknown. This study aims to explore the expression of CCN1 in infantile hemangioma and to investigate the effect of hypoxia on CCN1 and vascular endothelial growth factor-A (VEGF-A) production.

METHODS

Hemangioma-derived endothelial cells and hemangioma-derived stem cells were isolated from surgical specimens of proliferative infantile hemangioma. RNA extracted from infantile hemangioma tissue, hemangioma-derived endothelial cells, and hemangioma-derived stem cells was used to analyze gene expression by real-time polymerase chain reaction. The effects of CCN1 blockade were examined in hemangioma-derived stem cells. Immunostaining, immunoblotting, and enzyme-linked immunosorbent assays were used to assess protein expression.

RESULTS

By double-label immunofluorescence staining, the authors first identified that CCN1 was abundant in proliferative infantile hemangioma lesions and colocalized well with immature microvessels. The authors found that the mRNA level of CCN1 in proliferative infantile hemangioma was significantly higher than in healthy controls, as was involuting infantile hemangioma. Treatment with the hypoxia inducer cobalt chloride dramatically increased CCN1 production in hemangioma-derived endothelial cells in a time-dependent manner. Furthermore, blocking or knockdown of CCN1 expression reduced the expression of VEGF-A in hemangioma-derived stem cells. Lastly, the signaling pathway study showed that CCN1 up-regulation of VEGF-A synthesis in hemangioma-derived stem cells depends on nuclear factor-κB and JNK activation.

CONCLUSIONS

These findings provide new evidence that CCN1 participates in the crosstalk between hemangioma-derived endothelial cells and hemangioma-derived stem cells through promoting VEGF-A expression in the hypoxic environment of infantile hemangioma angiogenesis and vasculogenesis. Targeting of CCN1 might be a novel therapeutic strategy for infantile hemangioma.

Novel treatment avenues for uterine leiomyoma: a new implication for endothelin?

Cysteine-rich angiogenic inducer 61 (CYR61), an angiogenic factor whose expression is decreased in fibroids. The aim of the present study was to determine if CYR61 secretion in smooth muscle cells (SMCs) is regulated by hypoxia and through the endothelin A (ETA) receptor. SMCs from fibroids (fSMC) and the adjacent myometrium smooth muscle cells (mSMCs) were extracted from ten women undergoing hysterectomy for uterine fibroids and cultured with or without 1.0 µM of an ETA receptor antagonist for 24 h under either normal or hypoxic oxygen conditions. Cellular secretion of endothelin-1 (ET-1) and CYR61 were measured via enzyme linked immunosorbent assay in the cell culture media. SMCs were collected to determine cell proliferation and CYR61 protein expression via Western blot. ET-1 secretion was significantly increased in fSMC and was decreased with blockade of the ETA receptor under both normoxia (P=0.0004) and hypoxia (P=0.008). CYR61 expression was decreased in fSMCs and significantly increased with blockade of the ETA receptor under hypoxia (P=0.04). Cell proliferation decreased with ETA blockade under normoxia (P=0.0001) and hypoxia (P=0.001). These results suggest that suppression of CYR61 secretion in fSMC is regulated by the ET-1 and that blockade with ETA could be considered for a future treatment option.

Chronic Rhinosinusitis without Nasal Polyps

Chronic rhinosinusitis without nasal polyps (CRSsNP) is more prevalent than chronic rhinosinusitis with nasal polyps (CRSwNP). Certain diseases predispose to whereas others are associated with CRSsNP. Predisposing diseases include allergic and nonallergic upper and lower airway diseases, epithelial cell disorders, immunodeficiencies, autoimmune diseases, and some infectious diseases. In addition, environmental and host factors, examples of which include smoking, a higher incidence of abnormal biofilms, and innate immune defects, play a role in the pathogenesis of this disease. CRSsNP is characterized by histologic abnormalities, including basement membrane thickening (fibrosis) and goblet cell hyperplasia. Neutrophils and several chemokines, TGF-β and C-X-C motif chemokine ligand (CXCL)-8, play a role in CRSsNP remodeling. However, there are conflicting data about CRSsNP endotypes, for example, whether it is characterized by neutrophilia or eosinophilia or both. In spite of advancements and the understanding of the pathogenesis of this disease, additional study is necessary to better comprehend its underlying mechanisms, endotypes, and evidence-based treatment strategies.

High expression levels of Cyr61 and VEGF are associated with poor prognosis in osteosarcoma

Cysteine Rich Angiogenic Inducer 61 (Cyr61) and Vascular Endothelial Growth Factor (VEGF) are signaling proteins involved in the regulation of tumor angiogenesis and progression. The purpose of this study was to investigate the clinicopathological and prognostic significance of Cyr61 and VEGF expressions in osteosarcoma. Immunohistochemical staining was performed to evaluate the expression of both the proteins in 84 osteosarcoma samples. Correlation between Cyr61/VEGF expressions and clinicopathological parameters was determined using Rank sum test and Spearman's rank correlation coefficient. Prognostic factors were identified using univariate and multivariate Cox regression analysis. The expressions of Cyr61 and VEGF were weak in 26.2% and 17.9%, moderate in 26.2% and 23.8%, and strong in 47.6% and 58.3% of osteosarcoma samples, respectively. Cyr61 and VEGF expressions moderately correlated with each other in osteosarcoma, and exhibited significant association with Enneking stage and distant metastasis. In addition, the high expression of both proteins significantly correlated with short overall survival time in these patients. The key finding in this study was that both Cyr61 and VEGF expressions were independent prognostic indicators of overall survival. In summary, our results indicate that expression of Cyr61 and VEGF may serve as important prognostic predictors in patients with osteosarcoma.

ROS-dependent HMGB1 secretion upregulates IL-8 in upper airway epithelial cells under hypoxic condition

High-mobility group box 1 (HMGB1) mediates various functions according to the location. We tried to investigate the role of HMGB1 in upper airway under hypoxic conditions. We cultured primary normal human nasal epithelium (NHNE) cells under hypoxic conditions and evaluated the movement of HMGB1 by western blotting, immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). Reactive oxygen species (ROS) level was evaluated to estimate the translocation mechanism of HMGB1. The role of secreted HMGB1 was evaluated by ELISA assay. Furthermore, we collected human nasal mucosa samples and nasal lavage fluids from patients conditioned under hypoxic and non-hypoxic environment, and compared the expression of HMGB1 in human nasal mucosa samples by immunohistochemistry and the levels of HMGB1 in lavage fluids using ELISA assay. Hypoxia induced translocation of HMGB1 into the extracellular area and it was dependent on ROS produced by dual oxidase 2. Secreted HMGB1 was involved in the upregulation of interleukin (IL)-8. In human samples, HMGB1 was translocated from nucleus to the cytoplasm in hypoxic-conditioned nasal mucosa. HMGB1 was increased in nasal lavage samples of chronic rhinosinusitis patients, whose sinus mucosa was supposed to be hypoxic as compared with controls. We suggest that HMGB1 is secreted in hypoxic condition via ROS-dependent mechanism and secreted HMGB1 participates in IL-8 upregulation mediating inflammatory response.

Sirtuin 6 modulates hypoxia-induced autophagy in nasal polyp fibroblasts via inhibition of glycolysis

BACKGROUND

To elucidate the interaction between hypoxia-induced autophagy and glycolysis in nasal polyp fibroblasts, and the regulatory role of Sirtuin 6 (SIRT6) in the pathogenesis of nasal polyp.

OBJECTIVE

Through examining the expressions of lactate dehydrogenase (LDH), microtubule-associated protein II light chain 3 (LC3II) (an autophagy marker), and production of lactate under hypoxia, the interaction between autophagy and glycolysis was investigated. The role of SIRT6 on the hypoxia-induced autophagy and glycolysis was also examined.

METHODS

Nasal polyp specimens were used to examine the expressions of hypoxia-inducible factor (HIF) 1α, LDH, and LC3II by Western blot analysis, and primary cultures of nasal polyp fibroblasts were established from resected nasal polyps to measure hypoxia-induced LDH and LC3II expression by Western blot analysis and lactate production by colorimetry. Forced expression of SIRT6 with a lentiviral-based technique was used to evaluate its suppressive effect on autophagy and glycolysis. Immunohistochemical staining was performed to detect the expressions of SIRT6, LDH, and beclin (another autophagy marker) in nasal polyps.

RESULTS

Expression of HIF-1α, LDH, and an autophagy marker, LC3II, are increased in nasal polyp specimens, and forced expression of SIRT6 in nasal polyp fibroblasts inhibited LDH expression, lactate production under hypoxia, and SIRT6. An immunohistochemistry study of nasal polyp showed that SIRT6 expression was reduced and LDH and beclin were enhanced.

CONCLUSION

Analysis of these data indicated that hypoxia may contribute to the formation of nasal polyp by promoting autophagy in nasal polyp fibroblasts. Through the antiglycolytic activity of SIRT6, the autophagy was suppressed, which was beneficial to nasal polyp formation. Modulation of glucose metabolism through SIRT6-based strategy may possess therapeutic potential for nasal polyposis in the future.

The Role of the Fibroblast in Inflammatory Upper Airway Conditions

Upper airway inflammation is one of the most frequent health care presentations. This is perhaps not surprising with our exposure to a myriad of environmental microbes, pollutants, and allergens. The precise pathophysiological mechanisms that cause persistent, exaggerated, upper airway inflammation rather than acute resolving illness remain unclear. Analysis of upper airway specimens identifies specific inflammatory cells, cytokine signatures, and fibrotic airway remodeling. Recent research has highlighted the role of stromal cells in the generation and persistence of chronic inflammation. Rather than simply being scaffolding or extracellular matrix-secreting cells on which organ systems are built, stromal cells including fibroblasts and osteocytes have their own independent immunologic functions. Here, we review the emerging inflammatory roles of upper airway fibroblasts, the majority of which appear to influence immune cell chemotaxis and amplify the inflammatory response.

The role of hypoxia-inducible factor 1α in allergic rhinitis

BACKGROUND

Hypoxia-inducible factor (HIF) 1alpha is expressed under hypoxic conditions and plays an important role in immune and inflammatory responses. The role of HIF-1alpha in allergic airways has been investigated mainly in bronchial asthma. This study investigated the role of HIF-1alpha in mouse models and patients with allergic rhinitis (AR).

METHODS

Balb/c mice were sensitized with ovalbumin (OVA) and alum and were challenged intranasally with OVA. The HIF-1alpha inhibitor, 2-methoxyestradiol (2-ME), was administered intraperitoneally and multiple parameters of allergic responses were evaluated. HIF-1alpha and vascular endothelial growth factor (VEGF) mRNA and protein expression were also evaluated in patients with AR and a correlation analysis between mRNA expression and allergic symptoms was performed.

RESULTS

In mouse models, the HIF-1alpha inhibitor 2-ME reduced allergic symptoms and eosinophilic infiltration into the nasal mucosa. 2-ME was found to suppress IgE production and inhibit local Th2 cytokine transcription in the nasal mucosa and systemic Th2 cytokine production by splenocytes. 2-ME also decreased HIF-1 and VEGF expression in nasal mucosa. An increase in HIF-1alpha and VEGF expression in the nasal mucosa of patients with AR was also observed.

CONCLUSION

Our data suggest that HIF-1alpha plays an important role in mouse models and patients with AR. HIF-1alpha inhibitors induce antiallergic effects by decreasing both local and systemic Th2 cytokine (IL-4 and IL-5) production, IgE production, and eosinophil infiltration into the nasal mucosa in an AR model. HIF-1alpha and VEGF expression increased in the nasal mucosa of patients with AR, showing the role of HIF-1alpha in disease pathogenesis.

Cyr61 is involved in neutrophil infiltration in joints by inducing IL-8 production by fibroblast-like synoviocytes in rheumatoid arthritis

Introduction

It is well known that neutrophils play very important roles in the development of rheumatoid arthritis (RA) and interleukin (IL)-8 is a critical chemokine in promoting neutrophil migration. We previously showed that increased production of Cyr61 by fibroblast-like synoviocytes (FLS) in RA promotes FLS proliferation and Th17 cell differentiation, thus Cyr61 is a pro-inflammatory factor in RA pathogenesis. In this study, we explored the role of Cyr61 in neutrophil migration to the joints of RA patients.

Methods

RA FLS were treated with Cyr61 and IL-8 expression was analyzed by real-time PCR and ELISA. The migration of neutrophils recruited by the culture supernatants was determined by the use of a chemotaxis assay. Mice with collagen-induced arthritis (CIA) were treated with anti-Cyr61 monoclonal antibodies (mAb), or IgG1 as a control. Arthritis severity was determined by visual examination of the paws and joint destruction was determined by hematoxylin-eosin (H&E) staining. Signal transduction pathways in Cyr61-induced IL-8 production were investigated by real-time PCR, western blotting, confocal microscopy, luciferase reporter assay or chromatin immunoprecipitation (ChIP) assay.

Results

We found that Cyr61 induced IL-8 production by RA FLS in an IL-1β and TNF-α independent pathway. Moreover, we identified that Cyr61-induced IL-8-mediated neutrophil migration in vitro. Using a CIA animal model, we found that treatment with anti-Cyr61 mAb led to a reduction in MIP-2 (a counterpart of human IL-8) expression and decrease in neutrophil infiltration, which is consistent with an attenuation of inflammation in vivo. Mechanistically, we showed that Cyr61 induced IL-8 production in FLS via AKT, JNK and ERK1/2-dependent AP-1, C/EBPβ and NF-κB signaling pathways.

Conclusions

Our results here reveal a novel role of Cyr61 in the pathogenesis of RA. It promotes neutrophil infiltration via up-regulation of IL-8 production in FLS. Taken together with our previous work, this study provides further evidence that Cyr61 plays a key role in the vicious cycle formed by the interaction between infiltrating neutrophils, proliferated FLS and activated Th17 cells in the development of RA.

Prostaglandin E2 Induces IL-6 and IL-8 Production by the EP Receptors/Akt/NF-κB Pathways in Nasal Polyp-Derived Fibroblasts

Purpose

Interleukin 6 (IL-6) and IL-8 participate in the pathogenesis of chronic rhinosinusitis with nasal polyps, and their levels are increased by prostaglandin E2 (PGE2) in different cell types. The purposes of this study were to determine whether PGE2 has any effect on the increase in the levels of IL-6 and IL-8 in nasal polyp-derived fibroblasts (NPDFs) and subsequently investigate the possible mechanism of this effect.

Methods

Different concentrations of PGE2 were used to stimulate NPDFs at different time intervals. NPDFs were treated with agonists and antagonists of E prostanoid (EP) receptors. To determine the signaling pathway for the expression of PGE2-induced IL-6 and IL-8, PGE2 was treated with Akt and NF-κB inhibitors in NPDFs. Reverse transcription-polymerase chain reaction for IL-6 and IL-8 mRNAs was performed. IL-6 and IL-8 levels were measured byenzyme-linked immunosorbent assay (ELISA). The activation of Akt and NF-κB was evaluated by western blot analysis.

Results

PGE2 significantly increased the mRNA and protein expression levels of IL-6 and IL-8 in NPDFs. The EP2 and EP4 agonists and antagonists induced and inhibited IL-6 expression. However, the EP4 agonist and antagonist were only observed to induce and inhibit IL-8 expression level. The Akt and NF-κB inhibitors significantly blocked PGE2-induced expression of IL-6 and IL-8.

Conclusions

PGE2 increases IL-6 expression via EP2 and EP4 receptors, and IL-8 expression via the EP4 receptor in NPDFs. It also activates the Akt and NF-κB signal pathways for the production of IL-6 and IL-8 in NPDFs. These results suggest that signaling pathway for IL-6 and IL-8 expression induced by PGE2 might be a useful therapeutic target for the treatment of nasal polyposis.

Prognostic and predictive value of serum vascular endothelial growth factor (VEGF) in squamous cell carcinoma of the head and neck

INTRODUCTION

This study aimed to investigate the prognostic and predictive value of serum vascular endothelial growth factor (VEGF) in head and neck squamous cell carcinoma (HNSCC).

METHOD

Preoperative and 6-month postoperative serum VEGF levels were measured using a quantitative sandwich enzyme immunoassay technique in 55 consecutive patients with HNSCC and two control groups. The first control group included normal, healthy, age- and sex-matched individuals (n = 20), while the second control group included the patients who had history of HNSCC and were free of disease for at least 5 years (n = 25).

RESULTS

The mean baseline serum VEGF concentrations of the 55 patients with HNSCC and the first and the second control groups were 437.86, 42.56, and 48.03 pg/ml, respectively (P < 0.001). After a median follow-up of 75 months, 15 patients of the study group developed recurrent disease and 40 patients remained free of disease. The mean preoperative and 6-month postoperative serum VEGF levels for the 40 patients who did not have recurrent disease were respectively 327.69 and 153.50 pg/ml compared to 731.72 and 692.96 pg/ml for the 15 patients with recurrent disease (P < 0.001). High (≥540 pg/ml) serum VEGF level was associated with poor overall survival (P < 0.001). Moreover, multivariate analysis showed node stage (P < 0.001) and preoperative serum VEGF level (P = 0.020) as significant, independent prognostic factors for overall survival.

CONCLUSION

Preoperative or postoperative elevated serum levels of VEGF are highly predictive for disease recurrence and are associated with poor disease-free and overall survival of patients with HNSCC.

Features of airway remodeling in different types of Chinese chronic rhinosinusitis are associated with inflammation patterns

BACKGROUND

The remodeling patterns in different types of chronic rhinosinusitis (CRS) have rarely been compared, particularly the difference between eosinophilic and noneosinophilic CRS with nasal polyps (CRSwNP). Moreover, whether there is a link between remodeling and inflammation remains controversial.

OBJECTIVE

To directly compare the remodeling features of different CRS and to explore their relationship with inflammation in Chinese patients.

METHODS

Histologic characteristics of surgical samples were analyzed in 33 controls, 72 eosinophilic and 76 noneosinophilic CRSwNP, and 72 CRS without nasal polyps (CRSsNP) patients. Tissue samples from 38 controls, 26 eosinophilic and 26 noneosinophilic CRSwNP, and 32 CRSsNP patients were measured for mRNA and/or protein expression of profibrotic growth factors, metalloproteinases (MMPs), tissue inhibitor of metalloproteinases (TIMPs), hypoxia-inducible factor (HIF)-1α, interleukin (IL)-8, eosinophil cationic protein (ECP), and myeloperoxidase (MPO).

RESULTS

The amount of collagen decreased, whereas the edema scores increased, from CRSsNP to noneosinophilic CRSwNP and to eosinophilic CRSwNP. Transforming growth factor (TGF)-β2 protein levels were enhanced in CRSsNP compared with CRSwNP. TIMP-4 protein levels decreased in eosinophilic CRSwNP compared with noneosinophilic CRSwNP and CRSsNP. The number of neutrophils decreased from CRSsNP to noneosinophilic CRSwNP and to eosinophilic CRSwNP. ECP levels were only up-regulated in eosinophilic CRSwNP. ECP levels and neutrophil number correlated positively with the severity of edema and fibrosis, respectively. Neutrophils were the major sources of TGF-β2 in CRSsNP and noneosinophilic CRSwNP.

CONCLUSION

Distinct remodeling patterns are revealed for different types of CRS, particularly for eosinophilic and noneosinophilic CRSwNP. Tissue remodeling associates with inflammation in CRS.

Genetics and phenotyping in chronic sinusitis

Chronic sinusitis with nasal polyposis historically has been treated as a single monolithic clinical disorder. Just as asthma is now accepted as numerous heterogeneous diseases, chronic sinusitis should also be viewed as comprising several diseases with varying causes, with each one characterized by distinct histologic and gene and protein expression patterns. This includes recognition of the need to define these diseases based on the presence or absence of an eosinophilic infiltrate but also on additional distinctions based on unique agents that drive their development and perpetuation. As a collection of heterogeneous diseases, proper differential diagnosis is required to delineate appropriate therapeutic intervention. This review will focus on recognized distinct presentations of chronic sinus disease, including distinguishing the clinical presentations, cellular and molecular characteristics, genetic differences, and current treatment options for each.