High-dose intranasal application of titanium dioxide nanoparticles induces the systemic uptakes and allergic airway inflammation in asthmatic mice.

BACKGROUND: Titanium dioxide nanoparticles (TiO2 NPs) have a wide range of applications in several industrial and biomedical domains. Based on the evidence, the workers exposed to inhaled nanosized TiO2 powder are more susceptible to the risks of developing respiratory diseases. Accordingly, this issue has increasingly attracted the researchers' interest in understanding the consequences of TiO2 NPs exposure. Regarding this, the present study was conducted to analyze the local effects of TiO2 NPs on allergic airway inflammation and their uptake in a mouse model of ovalbumin (OVA)-induced allergic airway inflammation. METHODS: For the purpose of the study, female BALB/c mice with or without asthma were intranasally administered with TiO2 NPs. The mice were subjected to histological assessment, lung function testing, scanning electron microscopy (SEM), inductively coupled plasma mass spectrometry (ICP-MS), and NP uptake measurement. In addition, T helper (Th) 1/Th2 cytokines were evaluated in the lung homogenate using the enzyme-linked immunosorbent assay. RESULTS: According to the results, the mice receiving OVA alone or OVA plus TiO2 NPs showed eosinophilic infiltrates and mucus overproduction in the lung tissues, compared to the controls. Furthermore, a significant elevation was observed in the circulating Th2 cytokines, including interleukin (IL)-4, IL-5, and IL-13 after NP exposure. The TiO2 NPs were taken up by alveolar macrophages at different time points. As the results of the SEM and ICP-MS indicated, TiO2 NPs were present in most of the organs in both asthmatic and non-asthmatic mice. CONCLUSION: Based on the findings of the current study, intranasally or inhalation exposure to high-dose nanosized TiO2 particles appears to exacerbate the allergic airway inflammation and lead to systemic uptake in extrapulmonary organs. These results indicate the very important need to investigate the upper limit of intranasally or inhalation exposure to nanosized TiO2 particles in occupational and environmental health policy.

A Dermatologist's Ammunition in the War Against Smoking: A Photoaging App.

This viewpoint reviews the perspectives for dermatology as a specialty to go beyond the substantial impact of smoking on skin disease and leverage the impact of skin changes on a person's self-concept and behavior in the design of effective interventions for smoking prevention and cessation.

Increase of Mast Cell-Nerve Association and Neuropeptide Receptor Expression on Mast Cells in Perennial Allergic Rhinitis.

OBJECTIVES: Mast cells (MCs) and nerves play an important role in allergic rhinitis (AR), but little is known about their crosstalk in AR. The aim of this study was to investigate MC-nerve interaction in the human nasal mucosa during AR. METHODS: The association between MCs and nerves, the expression of neuropeptide receptors (neurokinin 1 receptor [NK1R], neurokinin 2 receptor [NK2R], calcitonin gene-related peptide receptor [CGRPR], and MrgX2) on MCs, and protease-activated receptor 2 (PAR2) and tyrosine receptor kinase A (TrkA) on nerve fibres in the human nasal mucosa were investigated with immunofluorescence and real-time PCR. RESULTS: The association between MCs and nerves was found to be significantly increased, although the numbers of MCs and nerve fibres were unchanged during AR. MCs expressing tryptase-chymase (MCtc) were frequently associated with nerve fibres and these contacts increased significantly in AR. Neuropeptide receptors NK1R, NK2R, and CGRPR were firstly found to be largely localised on MCs. The number of MCs expressing NK1R and NK2R, but not CGRPR, was significantly increased in AR. Interestingly, MCtc mostly expressed these neuropeptide receptors. The newly discovered tachykinin receptor MrgX2 was not expressed on nasal MCs, but was expressed on gland cells and increased in AR. Additionally, tachykinergic nerve fibres were found to express PAR2 or TrkA as receptors for MCs. CONCLUSIONS: This study revealed for the first time an increase of MC-nerve association and neuropeptide receptor expression on MCs during AR as well as nerve fibres containing receptors for MCs. These results suggest that targeting or controlling airway sensory nerve function as a modulator of MCs may prevent allergic airway inflammation such as AR.

Nanotechnology in respiratory medicine.

Like two sides of the same coin, nanotechnology can be both boon and bane for respiratory medicine. Nanomaterials open new ways in diagnostics and treatment of lung diseases. Nanoparticle based drug delivery systems can help against diseases such as lung cancer, tuberculosis, and pulmonary fibrosis. Moreover, nanoparticles can be loaded with DNA and act as vectors for gene therapy in diseases like cystic fibrosis. Even lung diagnostics with computer tomography (CT) or magnetic resonance imaging (MRI) profits from new nanoparticle based contrast agents. However, the risks of nanotechnology also have to be taken into consideration as engineered nanomaterials resemble natural fine dusts and fibers, which are known to be harmful for the respiratory system in many cases. Recent studies have shown that nanoparticles in the respiratory tract can influence the immune system, can create oxidative stress and even cause genotoxicity. Another important aspect to assess the safety of nanotechnology based products is the absorption of nanoparticles. It was demonstrated that the amount of pulmonary nanoparticle uptake not only depends on physical and chemical nanoparticle characteristics but also on the health status of the organism. The huge diversity in nanotechnology could revolutionize medicine but makes safety assessment a challenging task.