p63+Krt5+ basal cells are increased in the squamous metaplastic epithelium of patients with radiation-induced chronic Rhinosinusitis

Impairment mechanism of nasal mucosa after radiotherapy for nasopharyngeal carcinoma

The nasal mucosa, which performs the crucial functions of filtering, humidifying and temperature regulation, is one of the most vulnerable areas of nasopharyngeal carcinoma (NPC) patients after radiotherapy (RT). Following RT, NPC patients experience a series of pathological changes in the nasal mucosa, ultimately leading to physiological dysfunction of the nasal epithelium. This article systematically reviews the clinical and pathological manifestations of RT-related nasal damage in NPC patients and summarizes the potential mechanism of damage to the human nasal epithelium by RT. Finally, we outline the current mechanistic models of nasal epithelial alterations after RT in NPC patients and provide additional information to extend the in-depth study on the impairment mechanisms of the nasal mucosa resulting from RT. We also describe the relationship between structural and functional alterations in the nasal mucosa after RT to help mitigate and treat this damage and provide insights informing future clinical and fundamental investigations.

Moderate Dose Irradiation Induces DNA Damage and Impairments of Barrier and Host Defense in Nasal Epithelial Cells in vitro

Purpose

Radiotherapy (RT) is the mainstay treatment for head and neck cancers. However, chronic and recurrent upper respiratory tract infections and inflammation have been commonly reported in patients post-RT. The underlying mechanisms remain poorly understood.

Method and Materials

We used a well-established model of human nasal epithelial cells (hNECs) that forms a pseudostratified layer in the air-liquid interface (ALI) and exposed it to single or repeated moderate dose γ-irradiation (1Gy). We assessed the DNA damage and evaluated the biological properties of hNECs at different time points post-RT. Further, we explored the host immunity alterations in irradiated hNECs with polyinosinic-polycytidylic acid sodium salt (poly [I:C]) and lipopolysaccharides (LPS).

Results

IR induced DNA double strand breaks (DSBs) and triggered DNA damage response in hNECs. Repeated IR significantly reduced basal cell proliferation with low expression of p63/KRT5 and Ki67, induced cilia loss and inhibited mucus secretion. In addition, IR decreased ZO-1 expression and caused a significant decline in the transepithelial electrical resistance (TEER). Moreover, hyperreactive response against pathogen invasion and disrupted epithelial host defense can be observed in hNECs exposed to repeated IR.

Conclusion

Our study suggests that IR induced prolonged structural and functional impairments of hNECs may contribute to patients post-RT with increased risk of developing chronic and recurrent upper respiratory tract infection and inflammation.

Increased expression of SPRR1A is associated with a poor prognosis in pancreatic ductal adenocarcinoma

OBJECTIVES

Small proline-rich protein 1A (SPRR1A) is recognized as a squamous differentiation marker but is also upregulated in some non-squamous cancers. However, its expression in pancreatic ductal adenocarcinoma (PDAC) has not been investigated. This study elucidated the expression of SPRR1A in PDAC and its effect on the prognosis and malignant behavior of PDAC.

METHODS

We examined the SPRR1A expression by immunohistochemistry in 86 surgical PDAC cases and revealed the relationship between its expression and the prognosis of the PDAC patients. Furthermore, we overexpressed SPRR1A in pancreatic cancer cell lines (PK-1 and Panc-1) and assessed the phenotype and gene expression changes in vitro.

RESULTS

Among the 84 cases, excluding 2 with squamous differentiation, 31 (36.9%) had a high SPRR1A expression. The overall survival (median 22.1 months vs. 33.6 months, p = 0.0357) and recurrence-free survival (median 10.7 months vs. 15.5 months, p = 0.0298) were significantly lower in the high-SPRR1A-expression group than in the low-SPRR1A-expression group. A multivariate analysis indicated that a high SPRR1A expression (HR 1.706, 95% CI 1.018 to 2.862, p = 0.0427) and residual tumor status (HR 2.687, 95% CI 1.487 to 4.855, p = 0.00106) were independent prognostic factors. The analysis of TCGA transcriptome data demonstrated that the high-SPRR1A-expression group had a significantly worse prognosis than the low-SPRR1A-expression group, which supported our data. SPRR1A overexpression in PK-1 and Panc-1 did not result in remarkable changes to in vitro phenotypes, such as the cell proliferation, chemo-resistance, EMT, migration or global gene expression.

CONCLUSION

Increased expression of SPRR1A is associated with a poor prognosis in PDAC and may serve as a novel prognostic marker. However, our in vitro study suggests that the SPRR1A expression may be a consequence, not a cause, of the aggressive behavior of PDAC.

RHINOSINUSITIS IN PATIENTS IN POST-COVID-19 PERIOD: ETIOLOGY, CLINICAL AND MORPHOLOGICAL CHARACTERISTICS

OBJECTIVE

The aim is to identify the etiology, clinical and morphological features of rhinosinusitis in patients in post-COVID-19 period.

PATIENTS AND METHODS

Materials and methods: In the present study, it was carried out the analysis of 11 cases of rhinosinusitis, which developed after COVID-19 infection. The diagnosis of rhi¬nosinusitis was established on the basis of anamnesis, clinical and laboratory examination, specialized instrumental examination (rhinoendoscopy, X-ray, magnetic resonance imaging, spiral and 3D computed tomography). All patients underwent endoscopic sanitation of the nasal cavity, expansion of the maxillary anastomosis, maxillary sinusotomy, sanitation of the maxillary sinuses and removal of pathologically altered tissues. Microbiological examination of the swab from the nasal cavity was carried out in all patients. Histological and morphometric research methods were used during the morphological study of surgical material. The nonparametric Mann-Whitney U test was used to compare the means in the groups.

RESULTS

Results: The conducted comprehensive study made it possible to identify chronic atrophic rhinosinusitis at the stage of exacerbation caused by associations of bacteria and fungi in patients in post-COVID-19 period. Among bacteria, the authors most often noted Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumonia, Streptococcus pneumonia and Enterococcus faecalis. Among fungi, there were Aspergillus, Candida, Mucor and Coccidioides. Fungal infection was characterized by invasion into the mucous membrane of the nose and paranasal sinuses. In patients in post-COVID-19 period the invasive bacterial-fungal chronic atrophic rhinosinusitis at the stage of exacerbation was predominantly bilateral, characterized by the involvement of several or all paranasal sinuses in the process. Patients with such pathology complained of periodic fever, headaches and malaise; nasal congestion and constant difficulty in nasal breathing; yellowish-greenish-reddish discharge from the nasal cavity, sometimes with a fetid odor; discomfort and pain in the area of paranasal sinuses; immobility of the eyeball, hyposmia or anosmia; reduction or complete loss of vision. Frequent risk factors for the development of invasive bacterial-fungal chronic atrophic rhinosinusitis at the stage of exacerbation in patients in post-COVID-19 period were the information about moderate or severe course of this infection in anamnesis; comorbidities (predominantly diabetes mellitus, hypertensive disease and ischemic heart disease).

CONCLUSION

Conclusions: The study conducted by the authors made it possible to identify the etiological, clinical and morphological features, as well as risk factors of rhinosinusitis in patients in post-COVID-19 period. This information will contribute to a better understanding of such pathology by the doctors and improve the diagnostic and treatment process.

Dysfunction of epithelial permeability barrier induced by HMGB1 in 2.5D cultures of human epithelial cells

Airway and intestinal epithelial permeability barriers are crucial in epithelial homeostasis. High mobility group box 1 (HMGB1), increased by various stimuli, is involved in the induction of airway inflammation, as well as the pathogenesis of inflammatory bowel disease. HMGB1 enhances epithelial hyperpermeability. Two-and-a-half dimensional (2.5D) culture assays are experimentally convenient and induce cells to form a more physiological tissue architecture than 2D culture assays for molecular transfer mechanism analysis. In 2.5D culture, treatment with HMGB1 induced permeability of FITC-dextran into the lumen formed by human lung, nasal and intestinal epithelial cells. The tricellular tight junction molecule angulin-1/LSR is responsible for the epithelial permeability barrier at tricellular contacts and contributes to various human airway and intestinal inflammatory diseases. In this review, we indicate the mechanisms including angulin-1/LSR and multiple signaling in dysfunction of the epithelial permeability barrier induced by HMGB1 in 2.5D culture of human airway and intestinal epithelial cells.