The human paranasal sinuses are the major source of intrinsic nitric oxide (NO) production in the human airway. NO plays several roles in the maintenance of physiological homeostasis and the regulation of airway inflammation through the expression of three NO synthase (NOS) isoforms. Measuring NO levels can contribute to the diagnosis and assessment of allergic rhinitis (AR) and chronic rhinosinusitis (CRS). In symptomatic AR patients, pro-inflammatory cytokines upregulate the expression of inducible NOS (iNOS) in the inferior turbinate. Excessive amounts of NO cause oxidative damage to cellular components, leading to the deposition of cytotoxic substances. CRS phenotype and endotype classifications have provided insights into modern treatment strategies. Analyses of the production of sinus NO and its metabolites revealed pathobiological diversity that can be exploited for useful biomarkers. Measuring nasal NO based on different NOS activities is a potent tool for specific interventions targeting molecular pathways underlying CRS endotype-specific inflammation. We provide a comprehensive review of the functional diversity of NOS isoforms in the human sinonasal system in relation to these two major nasal disorders’ pathologies. The regulatory mechanisms of NOS expression associated with the substrate bioavailability indicate the involvement of both type 1 and type 2 immune responses.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a chronic inflammatory disease with a high symptom burden, including nasal congestion and smell disorders. This study performed a detailed transcriptomic analysis in CRSwNP classified as eosinophilic CRS (ECRS), nonECRS according to the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) criteria, and a group of ECRS with comorbid aspirin intolerant asthma (Asp). Gene expression profiles of nasal polyps and the uncinate process in CRSwNP patients and normal subjects (controls) were generated by bulk RNA barcoding and sequencing (BRB-seq). A differentially expressed genes (DEGs) analysis was performed using DESeq2 software in iDEP to clarify any relationship between gene expression and disease backgrounds. A total of 3004 genes were identified by DEGs analysis to be associated with ECRS vs control, nonECRS vs control, and Asp vs control. A pathway analysis showed distinct profiles between the groups. A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) showed distinct phenotype-specific pathways of expressed genes. In the specific pathway of “cytokine–cytokine receptor interaction”, the differentially expressed genes were widely distributed. This study indicates that transcriptome analysis using BRB-seq may be a valuable tool to explore the pathogenesis of type 2 inflammation in CRSwNP.

Platelet-activating factor (PAF) is a phospholipid-derived inflammatory mediator that triggers various inflammatory conditions, including eosinophil activation and recruitment. This study aimed to evaluate the expressions of PAF-metabolism-associated genes, namely genes coding the enzymes involved in PAF synthesis (LPCAT1, LPCAT2, LPCAT3, and LPCAT4), PAF degradation (PAFAH1B2, PAFAH1B3, and PAFAH2), and the gene for the PAF receptor (PTAFR) in subtypes of CRSwNP classified by clinical- or hierarchal-analysis-based classifications. Transcriptomic analysis using bulk RNA barcoding and sequencing (BRB-seq) was performed with CRSwNP, including eosinophilic CRS (ECRS) (n = 9), nonECRS (n = 8), ECRS with aspirin-exacerbated respiratory disease (Asp) (n = 3), and controls with a normal uncinate process mucosa (n = 6). PTAFR was only upregulated in ECRS and nonECRS. In the hierarchical cluster analysis with clusters 1 and 2 reflecting patients with low-to-moderate and high levels of type 2 inflammation, respectively, cluster 1 exhibited a significant downregulation of LPCAT2 and an upregulation of PTAFR expression, while cluster 2 showed an upregulation of LPCAT1, PAFAH1B2, and PTAFR and downregulation of PAFAH2 expression. Understanding this strong PAF-associated pathophysiology in the severe type 2 inflammation group could provide valuable insights into the treatment and management of CRSwNP.

Background/Objectives: Near-infrared photoimmunotherapy (NIR-PIT) represents a treatment approach for patients with locally advanced or recurrent head and neck cancers who are unsuitable for surgery post-standard therapy. Since its introduction in Japan in January 2021, NIR-PIT has been available exclusively under the national health insurance system, resulting in limited real-world clinical practice data. This study evaluated the association between NIR-PIT and overall survival (OS) in clinical practice. Methods: This single-center retrospective study included 45 patients with head and neck cancer who were not amenable to surgical resection owing to advanced local disease or regional recurrence without distant metastasis and who underwent NIR-PIT or systemic pharmacotherapy between January 2021 and April 2025. The primary endpoint was OS. Results: Twenty-two and 23 patients received NIR-PIT and pharmacotherapy, respectively. In the NIR-PIT group, irradiation was delivered to primary tumors in 20 patients, cervical lymph node lesions in one, and both primary and lymph node lesions in one. The median OS was 35 and 8 months, with median follow-up of 40 and 49 months in the NIR-PIT and pharmacotherapy groups, respectively. Among the NIR-PIT-eligible patients, 22 and 10 were treated with NIR-PIT and pharmacotherapy, respectively. The median OS was 35 and 8 months, with median follow-up of 40 and 24 months in the NIR-PIT and pharmacotherapy groups, respectively. Conclusions: NIR-PIT was independently associated with improved OS in patients with unresectable recurrent or metastatic head and neck cancer without distant metastasis. Prospective multicenter studies are warranted to validate these findings.

Transglutaminase (TGM) isoform catalyze the cross-linking reaction of identical or different substrate proteins. Eosinophil has been recognized in chronic rhinosinusitis with nasal polyps (CRSwNP) forming tissue eosinophil in nasal polyp (NP), and TGM isoforms are suggested to be associated with a critical role in asthma and other allergic conditions. The aim of this study was to reveal the association of specific TGM isoform with both the tissue eosinophil infiltration deeply concerning with the intractable severity of CRSwNP and the fibrin polymerization ability of TGM isoform associated with the tissue eosinophil infiltration, which lead to NP formation and/or maintenance in CRSwNP. NP tissues (CRSwNP group) and uncinate process (UP) (control group) were collected from patients with CRSwNP and control subjects. We examined: (1) the expression level of TGM isoforms by using a real-time polymerase chain reaction (PCR) and the comparison to the issue eosinophil count in the CRSwNP group, (2) the location of specific TGM isoform in the mucosal tissue using immunohistochemistry, (3) the inflammatory cell showing the colocalization of specific TGM isoform in Laser Scanning Confocal Microscopy (LSCM) imaging, and (4) the fibrin polymerase activity of specific TGM isoform using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A certain level of TGM 1, 2, 3, 5 expression was present in both the CRSwNP group and the control group. Only TGM 1 expression showed a positive significant correlation with the tissue eosinophil count in the CRSwNP group. The localization of TGM 1 in NP (CRSwNP) laid mainly in a submucosal layer as inflammatory cells and was at the cytoplasm in the tissue eosinophil. Fibrin polymerase activity of TGM 1 showed the same polymerase ability of factor XIIIA. TGM 1 might influence the NP formation and/or maintenance in CRSwNP related to the tissue eosinophil infiltration, which formed fibrin mesh composing NP stroma.

Chemoradiotherapy (CRT) is the standard treatment for locally advanced head and neck cancer; however, CRT may cause post-treatment dysphagia. Transcutaneous electrical sensory stimulation (TESS), developed in recent years for swallowing rehabilitation, is used at many medical facilities. Although TESS has been used for dysphagia in several fields, its safety and efficacy in patients with head and neck cancer remain to be clarified. Therefore, this study evaluated the safety of TESS in ten patients with head and neck cancers undergoing CRT. Swallowing rehabilitation intervention and TESS implementation were performed for all patients during CRT. Non-blood-toxicity adverse events (AEs), such as dermatitis and mucositis, occurred during CRT; however, the severity was less than grade 3. No patient experienced pain due to TESS. As survival time analysis using the Kaplan–Meier method for interferential current device implementation rates revealed a feasibility of 100% for up to 60 Gy and a feasibility of 78% for up to 70 Gy, TESS may be feasible until 70 Gy. This study confirmed the feasibility and safety of TESS in the head and neck region during CRT. Although the precise mechanism of TESS on dysphagia remains unclear, its continued use has great potential for improving sensory disturbance.