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The coronavirus SARS-CoV-2 is the causative agent of the ongoing severe acute respiratory disease pandemic COVID-19. Tissue and cellular tropism is one key to understanding the pathogenesis of SARS-CoV-2. We investigate the expression and subcellular localization of the SARS-CoV-2 receptor, angiotensin-converting enzyme 2 (ACE2), within the upper (nasal) and lower (pulmonary) respiratory tracts of human donors using a diverse panel of banked tissues. Here, we report our discovery that the ACE2 receptor protein robustly localizes within the motile cilia of airway epithelial cells, which likely represents the initial or early subcellular site of SARS-CoV-2 viral entry during host respiratory transmission. We further determine whether ciliary ACE2 expression in the upper airway is influenced by patient demographics, clinical characteristics, comorbidities, or medication use, and show the first mechanistic evidence that the use of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor blockers (ARBs) does not increase susceptibility to SARS-CoV-2 infection through enhancing the expression of ciliary ACE2 receptor. These findings are crucial to our understanding of the transmission of SARS-CoV-2 for prevention and control of this virulent pathogen.

Background: Nasal epithelial cells are the first site of encounter of the influenza virus, and their innate immune response might define subsequent inflammatory direction. Aims/objectives: We used metabolomics analysis to identify metabolic changes and the regulation of inflammatory cytokines in nasal epithelial cells upon influenza virus infection. Material and methods: We cultured nasal epithelial cells using air-liquid interface (ALI) model. Influenza virus (PR8) infection followed by metabolomic analysis was performed. Furthermore, cytokine expression was analyzed by cytokine array and RT-qPCR. Results: Metabolomic analysis revealed depletion of the tryptophan and accumulation of its metabolite, kynurenine, within 48 h. The major enzyme involved in the tryptophan metabolic pathway, indoleamine 2,3-dioxygenase (IDO), was overexpressed after infection. Cytokine expression array after infection showed increased levels of IL-1α, CCL2, IL-6, CXCL10, CCL5, and CXCL11, and after using 1-methyltryptophan (1-MT) as inhibitor, the expression levels of IL-6 and G-CSF were reduced. Conclusions and significance: Viral infection results in depletion of tryptophan and accumulation of kynurenine via increased cellular IDO activity. Inhibition of IDO activity or replenishment of tryptophan by local application may be a good therapeutic strategy for limiting the initial damage caused by influenza virus in nasal epithelial cells. [ABSTRACT FROM AUTHOR]

Key points We proposed a hierarchical framework including an unsupervised candidate image selection and a weakly supervised patch image detection based on multiple instance learning (MIL) to effectively estimate eosinophil quantities in tissue samples from whole slide images. MIL is an innovative approach that can help deal with the variability in cell distribution detection and enable automated eosinophil quantification from sinonasal histopathological images with a high degree of accuracy. The study lays the foundation for further research and development in the field of automated histopathological image analysis, and validation on more extensive and diverse datasets will contribute to real‐world application. We proposed a hierarchical framework including an unsupervised candidate image selection and a weakly supervised patch image detection based on multiple instance learning (MIL) to effectively estimate eosinophil quantities in tissue samples from whole slide images.MIL is an innovative approach that can help deal with the variability in cell distribution detection and enable automated eosinophil quantification from sinonasal histopathological images with a high degree of accuracy.The study lays the foundation for further research and development in the field of automated histopathological image analysis, and validation on more extensive and diverse datasets will contribute to real‐world application. [ABSTRACT FROM AUTHOR]

Objectives: Given the lack of consensus on the screening and treatment for chronic rhinosinusitis (CRS) in the patients undergoing hematopoietic stem cell transplantation (HSCT), we reviewed the risk factors for CRS to improve the efficiency of sinonasal screening and analyzed the effect of treating CRS in search of guidance for modifying current management strategies for rhinosinusitis in HSCT patients., Methods: We conducted a nested case-control study in a retrospective cohort of hematologic patients receiving HSCT from April 2011 to April 2021 and collected data on demographics, smoking/atopic status, hematological diseases, and features of rhinosinusitis for analysis. The associated factors for control of rhinosinusitis and survival were analyzed., Results: Fifty-eight CRS patients were identified, and another 116 age- and sex-matched controls were selected from HSCT patients without CRS. Allergy and smoking were risk factors for CRS in HSCT patients. The multivariable logistic analysis indicated that endoscopic sinus surgery (ESS) was an independent factor for better control of CRS. However, survival was not associated with rhinosinusitis-related factors, but only with hematologic-related factors, including allogenic HSCT, reduced-intensity conditioning, and remission., Conclusions: Sinonasal evaluation should be targeted to the high-risk group. ESS is effective in managing CRS, while control of CRS is not determinant of overall survival in patients receiving HSCT., Competing Interests: Declaration of competing interest nil., (Copyright © 2024 Formosan Medical Association. Published by Elsevier B.V. All rights reserved.)