Downregulation of TET2 Contributes to Nasal Polypogenesis Through Hypoxia-Inducible Factor 1α-Mediated Epithelial-to-Mesenchymal Transition

OBJECTIVES

Hypoxia-inducible factor 1α (HIF1α) and Tet methylcytosine dioxygenase 2 (TET2) have been reported to mediate nasal polypogenesis through the epithelial-to-mesenchymal transition (EMT). Additionally, HIF1α can regulate the expression and function of TET2. However, the precise mechanism of how TET2 regulates the EMT through HIF1α mediation in nasal epithelial cells is still poorly understood.

METHODS

Nasal tissue samples were collected from patients with chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP), CRS without nasal polyps (CRSsNP), and controls. The expression of HIF1α and TET2 was detected using Western blotting and immunohistochemistry. EMT markers (E-cadherin and vimentin) were also evaluated by immunohistochemistry. Primary human nasal epithelial cells (hNECs) were stimulated with CoCl2 to mimic hypoxia. Vitamin C (VC), a TET2 non-specific activator, and small interfering RNA (siRNA) transfection of TET2 were used to further determine the role of TET2 in hypoxia-induced EMT. Finally, reactive oxygen species (ROS) and Nrf2 were measured to explore the downstream consequences of TET2 in hypoxic hNECs.

RESULTS

TET2 levels were lower in the nasal epithelium of CRSwNP patients and were positively correlated with E-cadherin but negatively correlated with vimentin in CRS. However, HIF1α exhibited the opposite pattern and was negatively correlated with TET2 expression. CoCl2-simulated hypoxia led to EMT and increased HIF1α in hNECs in vitro, with simultaneous downregulation of TET2 expression. Addition of VC activated TET2 expression in hNECs, but inhibited EMT and HIF1α expression. Furthermore, siRNA knockdown of TET2 contributed to the EMT in CoCl2-simulated hNECs despite the addition of VC. Finally, TET2 regulated the EMT in hypoxic hNECs through Nrf2 expression and ROS generation.

CONCLUSION

TET2 was negatively correlated with HIF1α and EMT in vivo. TET2 was downregulated by HIF1α, resulting in the EMT in CoCl2-hypoxic hNECs via regulation of oxidative stress in vitro. Hence, TET2 might provide a new therapeutic approach for CRSwNP.

Differences in Clinical and Immunological Characteristics According to the Various Criteria for Tissue Eosinophilia in Chronic Rhinosinusitis With Nasal Polyps

OBJECTIVES

Several criteria exist for classifying chronic rhinosinusitis with nasal polyps (CRSwNP) as eosinophilic or non-eosinophilic. This study attempted to evaluate several criteria for defining eosinophilic CRSwNP from clinical and immunological perspectives.

METHODS

A cohort of 84 patients (73 patients with CRSwNP and 11 control patients) was retrospectively analyzed. Patients were divided into eosinophilic and non-eosinophilic CRSwNP based on four different criteria: eosinophils (EOS) accounting for more than 20% of the total inflammatory cells; ≥70 EOS per high-power field (HPF); >55 EOS/HPF; and ≥10 EOS/HPF. Preoperative clinical characteristics, the immunological profiles of 14 cytokines from nasal tissue, and postoperative outcomes were compared between eosinophilic and non-eosinophilic CRSwNP based on each criterion. These criteria were immunologically validated by using 14 cytokines to predict the performance of tissue eosinophilia with a random forest model.

RESULTS

Patients with eosinophilic CRSwNP were significantly older when the criterion of ≥10 EOS/HPF or EOS >20% was used. The number of patients with aspirin intolerance was significantly higher in eosinophilic CRSwNP based on the criterion of EOS >20%. From an immunological perspective, non-type 2 inflammatory cytokines were significantly higher in non-eosinophilic CRSwNP with the criterion of EOS >20% of the total inflammatory cells. In addition, the criterion of EOS >20% of the total inflammatory cells resulted in the best prediction of eosinophilic CRSwNP, with an accuracy of 88.10% and area under the curve of 0.94.

CONCLUSION

Clinical and immunological characteristics were different between eosinophilic and non-eosinophilic CRSwNP depending on a variety of criteria, and the.

RESULTS

of this study should be taken into account when choosing the criterion for defining eosinophilic CRSwNP and interpreting the data accordingly.

Expression of Estrogen Receptor-alpha in Nasal Polyps and the Effects of Dexamethasone on Estrogen Receptor-alpha Expression in RPMI 2650 Cells

BACKGROUND

Studies have reported that epithelial cell proliferation may be involved in the pathogenesis of nasal polyps (NPs). Estrogen receptor (ER)-α, one type of ER, is related to anti-inflammatory action and cell survival in certain tissues. In this study, we examined the presence or absence of ER-α in NPs and healthy inferior turbinate mucosae. We also investigated the effect of dexamethasone on ER-α expression, cell viability, and apoptosis in RPMI 2650 cells.

METHODS

Immunohistochemical staining and Western blot analysis were conducted to determine the expression of ER-α in 15 NPs and 15 healthy inferior turbinate mucosae. After treating RPMI 2650 cells with dexamethasone, ER-α expression was analyzed using Western blot analysis and cell viability was determined using the MTT assay. Western blot analysis and annexin V-phycoerythrin (PE) staining were used to examine apoptotic cell death.

RESULTS

Western blot analysis showed that ER-α expression was upregulated in 13 of the 15 NP tissues. Immunohistochemical staining for ER-α confirmed the results of the Western blot analysis. When RPMI 2650 cells were treated with dexamethasone, both ER-α expression and cell viability were decreased. Furthermore, the treatment of RPMI 2650 cells with dexamethasone increased apoptotic cell death, as shown by increased levels of BAX and cleaved caspase-3, decreased levels of Bcl-2, and an increased percentage of positive annexin V-PE stained cells.

CONCLUSION

ER-α expression was higher in NPs than in healthy inferior turbinate mucosae. When RPMI 2650 cells were treated with dexamethasone, ER-α expression was downregulated, cell viability decreased, and apoptosis increased. The decreased cell viability may be related, at least in part, to the decreased ER-α protein levels, which likely contributed to the induction of apoptotic cell death in RPMI 2650 cells.

Neutrophils as a Protagonist and Target in Chronic Rhinosinusitis

Neutrophils have traditionally been acknowledged as the first immune cells that are recruited to inflamed tissues during acute inflammation. By contrast, their importance in the context of chronic inflammation has been studied in less depth. Neutrophils can be recruited and are largely present in the nasal mucosa of patients with chronic rhinosinusitis (CRS) both in Asians and in Caucasians. Increased infiltration of neutrophils in patients with CRS has been linked to poor corticosteroid response and disease prognosis. Meanwhile, tissue neutrophils may possess specific phenotypic features distinguishing them from resting blood counterparts and are endowed with particular functions, such as cytokines and chemokines production, thus may contribute to the pathogenesis of CRS. This review aims to summarize our current understanding of the pathophysiologic mechanisms of CRS, with a focus on the roles of neutrophils. We discuss recruitment, function, and regulation of neutrophils in CRS and outline the potential therapeutic strategies targeting neutrophils.

Incomitant Exotropia After Nasal Polyp Surgery

BACKGROUND

Incomitant exotropia is one of ocular complication that has been reported after intranasal surgery. This case report aims to describe the causes of exotropia in a patient with a history of nasal polyp surgery.

CASE PRESENTATION

A 50-years-old male, came with the main complaint of double vision 1 month after nasal polyp surgery. He also complained his right eye turned outward. The visual acuity on the right eye was 6/7.5 with his head turn to the left. On the examination, the Hirschberg test was XT 45°, and the Krimsky test > 95 ∆BI. Duction and version test on the right eye were -4 adduction. There was no shifting on the cover-uncover test. Ishihara test was within normal limit, and there was suppression on the right eye in WFDT. On force generation test, we found limited adduction on the right eye and no restriction in force duction test. Head MRI showed atrophy of medial recti on the right eye, 2.2 mm in size. The patient underwent vertical muscle transposition procedure surgery, and it was found atrophy of medial recti without any rupture. Two months after surgery, the double vision was decreased, the result of the Hirschberg test was XT 30° and Krimsky test 65°∆BI.

DISCUSSION

Nasal polyp surgery-related incomitant exotropia mostly caused by extraocular muscles rupture. In this case, we found no rupture. Therefore, we suspected the abnormalities of muscles vascularisation, supported by the atrophy of medial recti.

The Effectiveness of Budesonide Nasal Irrigation After Endoscopic Sinus Surgery in Chronic Rhinosinusitis With Asthma

Objectives

Budesonide nasal irrigation was introduced recently for postoperative management of patients with chronic rhinosinusitis. The safety and therapeutic effectiveness of this procedure is becoming accepted by many physicians. The objective of this study was to evaluate the efficacy of postoperative steroid irrigation in patients with chronic rhinosinusitis and asthma.

Methods

This prospective study involved 12 chronic rhinosinusitis patients with nasal polyps and asthma who received oral steroid treatment for recurring or worsening disease. The 22-item Sinonasal Outcomes Test (SNOT-22) and Lund-Kennedy endoscopy scores were checked before nasal budesonide irrigation, and 1, 2, 4, and 6 months after irrigation. We also calculated the total amount of oral steroids and inhaled steroids in the 6 months before irrigation and the 6 months after it.

Results

The mean SNOT-22 score improved from 30.8±14.4 before irrigation to 14.2±8.7 after 6 months of irrigation (P=0.030). The endoscopy score also improved from 7.4±4.7 before irrigation to 2.2±2.7 after 6 months (P<0.001). The total amount of oral steroid was decreased from 397.8±97.6 mg over the 6 months before irrigation to 72.7±99.7 mg over the 6 months after irrigation (P<0.001).

Conclusion

Nasal irrigation with budesonide is an effective postoperative treatment for chronic rhinosinusitis with asthma, which recurs frequently, reducing the oral steroid intake.

Nasal polyp chitinolytic activity associated with smoking or allergy

BACKGROUND

Cells of the innate immune system that are implicated in allergy and immunity bind to chitin during tissue infiltration in a process negatively regulated by vertebrate chitinases. Both acidic mammalian chitinase (AMCase) and chitotriosidase (ChT) exert chitinolytic activity. The levels of activities of these enzymes in nasal polyps (NPs) of subjects who smoke or who suffer from allergies are unknown. In the present work, we measured the activities of AMCase and ChT in NPs of smokers and allergic subjects.

METHODS

We report a prospective cohort study in a tertiary care facility. AMCase and ChT activities of NPs were measured in buffers of several pH values using the fluorogenic substrate 4-methylumbelliferyl-β-d-N,N',N″-triacetyl-chitotriose.

RESULTS

The activities of AMCase and ChT in NPs did not differ significantly among smokers, nonsmokers, and ex-smokers. AMCase and ChT activities were significantly higher in NPs of allergic subjects than in NPs of those who did not suffer from allergy.

CONCLUSION

Increased levels of chitinolytic activities in NPs were associated with the allergic rhinitis. We suggest that control of such rhinitis may help to prevent the development and growth of NPs.

Nasal polyps - histopathologic spectrum

Analysis of 345 polypoidal masses in nose and nasal sinuses with clinical diagnosis of nasal polyp, observed in 10 years, revealed 175 (50.7%) non- neoplastic lesions and 170 (49.3%) neoplasms. Among the non- neoplastic lesions, there were 110 cases (62.8%) of true nasal polyps including 74 cases (67.3%) of allergic polyps and 36 (32.7%) inflammatory ones. The next common non- neoplastic polyp was due to rhinosporidiosis (31.4%). Benign neoplastic lesions consisted mainly of haemangioma (45.7%), angiofibroma (23.2%), fibroma (6.2%), transitional cell papilloma, inverted papilloma, adenoma-3.9% each. Squamous cell carcinoma was the commonest malignant lesion encountered (36.6%) followed by 19.5% of adenoid cystic carcinoma,17.1% of anaplastic carcinoma and 12.2% of transitional cell carcinoma. Adeno carcinoma (4.9%), Mucoepidermoid carcinoma (2.4%), non- Hodgkin lymphoma (4.9%) and embryonal rhabdomyosarcoma (2.4%) were the other malignant lesions.

Does amphotericin B nasal douching help prevent polyp recurrence following functional endoscopic sinus surgery?

BACKGROUND

Recurrence of nasal polyposis following surgical intervention is very common. Antifungal therapy has been an appealing alternative to reduce its recurrence and severity. Early studies showed definite positive response, but recent studies have raised doubts about its efficacy in treatment of polyposis.

METHODS

This prospective case-control clinical trial was conducted on 50 patients suffering from nasal polyposis in Isfahan University of medical sciences. All patients underwent functional endoscopic sinus surgery. CT scanning of paranasal sinuses was done preoperatively and 6 months postoperatively to stage the disease. Patients were assigned to two groups: amphotericine B group were instructed to irrigate the nasal cavity with a solution of amphotericine B, while the normal saline group used the physiologic normal saline for 6 months.

RESULTS

68% of patients in Normal saline and 84% of cases in amphotericine B group reported history of allergies. In amphotericine B group, stage of the disease improved in 84% of patients and remained unchanged in the rest. In normal saline group, imaging stage improved in 22 patients and remained unchanged in 3. The two cohorts were compared for reduction in imaging stage and no significant difference was found between them.

CONCLUSIONS

This study showed no benefits for topical amphotericin B solution over normal saline. It might be better to retreat to the traditional normal saline nasal douching following functional endoscopic sinus surgery in the treatment of polyposis.