Nanoplastics Penetrate Human Bronchial Smooth Muscle and Small Airway Epithelial Cells and Affect Mitochondrial Metabolism.

Micro- and nanoplastic particles, including common forms like polyethylene and polystyrene, have been identified as relevant pollutants, potentially causing health problems in living organisms. The mechanisms at the cellular level largely remain to be elucidated. This study aims to visualize nanoplastics in bronchial smooth muscle (BSMC) and small airway epithelial cells (SAEC), and to assess the impact on mitochondrial metabolism. Healthy and asthmatic human BSMC and SAEC in vitro cultures were stimulated with polystyrene nanoplastics (PS-NPs) of 25 or 50 nm size, for 1 or 24 h. Live cell, label-free imaging by holotomography microscopy and mitochondrial respiration and glycolysis assessment were performed. Furthermore, 25 and 50 nm NPs were shown to penetrate SAEC, along with healthy and diseased BSMC, and they impaired bioenergetics and induce mitochondrial dysfunction compared to cells not treated with NPs, including changes in oxygen consumption rate and extracellular acidification rate. NPs pose a serious threat to human health by penetrating airway tissues and cells, and affecting both oxidative and glycolytic metabolism.

The potential impact of nano- and microplastics on human health: Understanding human health risks.

Plastics are used all over the world. Unfortunately, due to limited biodegradation, plastics cause a significant level of environmental pollution. The smallest recognized to date are termed nanoplastics (1 nm [nm] up to 1 µm [µm]) and microplastics (1 µm-5 mm). These nano- and microplastics can enter the human body through the respiratory system via inhalation, the digestive tract via consumption of contaminated food and water, or penetration through the skin via cosmetics and clothes contact. Bioaccumulation of plastics in the human body can potentially lead to a range of health issues, including respiratory disorders like lung cancer, asthma and hypersensitivity pneumonitis, neurological symptoms such as fatigue and dizziness, inflammatory bowel disease and even disturbances in gut microbiota. Most studies to date have confirmed that nano- and microplastics can induce apoptosis in cells and have genotoxic and cytotoxic effects. Understanding the cellular and molecular mechanisms of plastics' actions may help extrapolate the risks to humans. The article provides a comprehensive review of articles in databases regarding the impact of nano- and microplastics on human health. The review included retrospective studies and case reports of people exposed to nanoplastics and microplastics. This research highlights the need for further research to fully understand the extent of the impact of plastics on human health.

Validated allergen exposure chamber is plausible tool for the assessment of house dust mite-triggered allergic rhinitis.

BACKGROUND: Allergen exposure chamber (AEC) is a clinical facility that allows exposure to allergenic airborne particles in controlled environment. Although AECs offer stable levels of airborne allergens, the validation of symptoms and other endpoints induced by allergen challenge is key for their recommendation as a plausible tool for the assessment of patients, especially in clinical research. This study aimed to demonstrate the reproducibility of defined clinical endpoints after AEC house dust mite (HDM) challenge under optimal conditions in patients with allergic rhinitis (AR). METHOD: HDM was distributed at different concentrations. The assessment was subjective by the patients: total nasal symptom score (TNSS), visual analog scale (VAS), and objective by the investigator: acoustic rhinometry, peak nasal inspiratory flow (PNIF), and nasal secretion weight. Safety was assessed clinically and by peak expiratory flow rate (PEFR) and forced expiratory volume in the first second (FEV1 ). RESULTS: Constant environment: temperature, humidity, and carbon dioxide (CO2 ) concentration were maintained during all challenges. The concentration of HDM on average remained stable within the targeted values: 1000, 3000, 5000, 7000 particles (p)/m3 . Most symptoms were observed at concentrations 3000 p/m3 or higher. The symptoms severity and other endpoints results were reproducible. 5000 p/m3 , and challenge duration of 120 min were found optimal. The procedure was safe with no lung function abnormalities due to challenge. CONCLUSION: HDM challenge in ALL-MED AEC offers a safe and reliable method for inducing symptoms in AR patients for the use in controlled clinical studies including allergen immunotherapy.

Histamine: A Mediator of Intestinal Disorders-A Review.

Within the gastrointestinal tract, histamine is present at relatively high concentrations, especially during inflammatory processes. Histamine is a biogenic amine with numerous effects on many cell types, mediated by the activation of its four different histamine receptors (H1-H4Rs). It is produced and released by immune cells as mast cells and basophils. Some cells such as dendritic cells or T cells can express histidine decarboxylase, an enzyme for histamine synthesis after stimulation. The same can be done by the human gut microbiota. The production of histamine by bacteria in the human gut influence the immune response, although the major source of histamine is food. The large spectrum of histamine effects on a number of cellular processes results in various gastrointestinal disorders including food allergy, histamine intolerance, irritable bowel syndrome, and inflammatory bowel disease, among others. In this review, the protective or pathogenic effects of histamine on various gut disorders are discussed.