An In Vitro Study Evaluating the Safety of Mesalazine on Human Nasoepithelial Cells.

Chronic rhinosinusitis (CRS) is a disease characterised by the inflammation of the nasal and paranasal cavities. It is a widespread condition with considerable morbidity for patients. Current treatment for chronic rhinosinusitis consists of appropriate medical therapy followed by surgery in medically resistant patients. Although oral steroids are effective, they are associated with significant morbidity, and disease recurrence is common when discontinued. The development of additional steroid sparing therapies is therefore needed. Mesalazine is a commonly used therapeutic in inflammatory bowel disease, which shares a similar disease profile with chronic rhinosinusitis. This exploratory in vitro study aims to investigate whether mesalazine could be repurposed to a nasal wash, which is safe on human nasoepithelial cells, and retains its anti-inflammatory effects. CRS patients' human nasal epithelial cells (HNECs) were collected. HNECs were grown at an air-liquid interface (ALIs) and in a monolayer and challenged with mesalazine or a non-medicated control. Transepithelial electrical resistance, paracellular permeability, and toxicity were measured to assess epithelial integrity and safety. The anti-inflammatory effects of mesalazine on the release of interleukin (IL)-6 and tumour necrosis factor alpha (TNF-α) were analysed using human leukemia monocytic cell line (THP-1). mesalazine did not impact the barrier function of HNEC-ALIs and was not toxic when applied to HNECs or THP-1 cells at concentrations up to 20 mM. mesalazine at 0.5 and 1 mM concentrations significantly inhibited TNF-α release by THP-1 cells. mesalazine effectively decreases TNF-α secretion from THP-1 cells, indicating the possibility of its anti-inflammatory properties. The safety profile of mesalazine at doses up to 20 mM suggests that it is safe when applied topically on HNECs.

Hydrocortisone metabolism by Staphylococcus: Effects on anti-inflammatory and antimicrobial action.

KEY POINTS: Hydrocortisone 21-hemisuccinate (HCHS) influenced the growth and metabolism of Staphylococcus aureus S. aureus metabolic activity was high and antibiotic susceptibility low at 1.4 mg/mL HCHS S. aureus metabolized HCHS to cortisol and reduced poly(I:C)-induced IL-6 secretion.

Phenotypic consequences of a nanophthalmos-associated TMEM98 variant in human and mouse.

Nanophthalmos is characterised by shorter posterior and anterior segments of the eye, with a predisposition towards high hyperopia and primary angle-closure glaucoma. Variants in TMEM98 have been associated with autosomal dominant nanophthalmos in multiple kindreds, but definitive evidence for causation has been limited. Here we used CRISPR/Cas9 mutagenesis to recreate the human nanophthalmos-associated TMEM98 p.(Ala193Pro) variant in mice. The p.(Ala193Pro) variant was associated with ocular phenotypes in both mice and humans, with dominant inheritance in humans and recessive inheritance in mice. Unlike their human counterparts, p.(Ala193Pro) homozygous mutant mice had normal axial length, normal intraocular pressure, and structurally normal scleral collagen. However, in both homozygous mice and heterozygous humans, the p.(Ala193Pro) variant was associated with discrete white spots throughout the retinal fundus, with corresponding retinal folds on histology. This direct comparison of a TMEM98 variant in mouse and human suggests that certain nanophthalmos-associated phenotypes are not only a consequence of a smaller eye, but that TMEM98 may itself play a primary role in retinal and scleral structure and integrity.

Trimellitic anhydride facilitates transepithelial permeability disrupting tight junctions in sinonasal epithelial cells.

Trimellitic anhydride (TMA) is a chemical agent classified as a low molecular weight (LMW) agent causing occupational rhinitis (OR) or asthma. Although TMA is recognized as a respiratory sensitizer, the direct and non-immunologic effects of TMA remain unclear. Air- liquid interface (ALI) cultured human nasal epithelial cells (HNECs) derived from control subjects were treated with TMA, followed by measurement of the transepithelial electrical resistance (TEER), paracellular permeability of fluorescein isothiocyanate (FITC)-dextran and immunofluorescence of tight junction proteins claudin-1 and zonula occludens-1 (ZO-1). The cytotoxicity of TMA was evaluated by lactate dehydrogenase (LDH) assay. TMA at concentrations of 2 and 4 mg/mL significantly reduced the TEER within 10 min (p = 0.0177 on 2 mg/mL; p < 0.0001 on 4 mg/mL). The paracellular permeability of FITC-dextran was significantly increased upon challenge with 4 mg/mL TMA for 3 h (p = 0.0088) and 6 h (p = 0.0004). TMA treatment induced a reduction in the fluorescence intensity of claudin-1 and ZO-1 in a dose-dependent manner. LDH assay revealed 4 mg/mL TMA induced cytotoxicity only after 6 h incubation, while 1 or 2 mg/mL TMA caused no cytotoxicity. Our results suggest that TMA has a potential to penetrate the epithelial barrier by disrupting claudin-1 and ZO-1, indicating an important role for sensitization and OR development.

Green synthesized colloidal silver is devoid of toxic effects on primary human nasal epithelial cells in vitro.

Evaluating the safety of previously fabricated and effective green synthetized colloidal silver (GSCS) on the mucosal barrier structure and function is essential prior to conduct human trials. The GSCS was applied to primary human nasal epithelial cells (HNECs) grown in an air-liquid interface (ALI) culture. Epithelial barrier integrity was evaluated by measuring the transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-dextran paracellular permeability. Ciliary beat frequency (CBF) was quantified. Effects of the GSCS on cell viability and inflammation were examined through lactate dehydrogenase, the 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide viability assay and interleukin 6 (IL-6) enzyme linked immunosorbent assay. The localization and transportation of GSCS within HNECs and their HNEC-ALI cultures was assessed by transmission electron microscopy and inductively coupled plasma-mass-spectrometry, respectively. Application of GSCS to HNECs-ALI cultures for up to 2 h caused a significant reduction in the TEER values, however, it did not drop within the first 10 and 20 min for CRS and non-CRS control HNECs. The paracellular permeability, cell viability, IL-6 secretion and CBF remained unchanged. No GSCS was observed within or transported across HNECs. In conclusion, application of GSCS to HNECs is devoid of toxic effects.

The effect of chemical and structural modifiers on the haemostatic process and cytotoxicity of the beta-chitin patch.

Beta-chitin patch has previously been proven to be an effective haemostat, but whether modifying the patch affects its efficacy and safety, remains unanswered. In this study, the patch was modified using polyethylene oxide, Pluronic-F127, calcium, increased thickness or polyphosphate, and their effect on the process of haemostasis and cytotoxicity was tested and compared with standard-of-care, Surgicel and FloSeal. Whole blood collected from volunteers was applied to the patches to test their whole blood clotting and thrombin generation capacities, whilst platelet isolates were used to test their platelet aggregation ability. The fluid absorption capacity of the patches was tested using simulated body fluid. Cytotoxicity of the patches was tested using AlamarBlue assays and PC12 cells and the results were compared with the standard-of-care. In this study, beta-chitin patch modifications failed to improve its whole blood clotting, platelet aggregation and thrombin generation capacity. Compared to non-modified patch, modifications with polyethylene oxide or calcium reduced platelet aggregation and thrombin generation capacity, while increasing the thickness or adding polyphosphate decreased platelet aggregation capacity. The cytotoxicity assays demonstrated that the beta-chitin patches were non-toxic to cells. In vivo research is required to evaluate the safety and efficacy of the beta-chitin patches in a clinical setting.

Acoustic drug delivery to the maxillary sinus.

Acoustic drug delivery (ADD) is an innovative method for drug delivery to the nose and paranasal sinuses and can be used to treat chronic rhinosinusitis (CRS). The underlying mechanism of ADD is based on the oscillatory exchange of air between the nasal cavity (NC) and the maxillary sinus (MS) through the ostium, which assists with the transfer of the drug particles from the NC to the sinuses. This study aims to examine the efficacy of ADD for drug delivery to the MS using an acoustic wave applied to nebulised aerosols entering the nostril. Here, the effect of acoustic frequency, amplitude, and nebulisation flowrate on the efficiency of ADD to the MS is investigated experimentally. A computational fluid dynamics model was also developed to understand the deposition and transport patterns of the aerosols. The results showed that superimposing an acoustic frequency of 328 Hz, which is the resonance frequency of the selected 3D printed model of the NC-MS combination, on the nebulised aerosols could improve the efficiency of the drug delivery to the MS by 75-fold compared with non-acoustic drug delivery case (p < 0.0001). The experimental data also shows that an increase in the amplitude of excitation, increases the concentration of aerosol deposition in the MS significantly; however, it reaches to a plateau at a sound pressure level of 120 dB re 20 µPa.