Health implications of plastics in our ecosystem
Facilitated by Professor Magdalena Plebanski (RMIT University)
Professor Deborah Glass (Monash University)
Pollution by nano and microplastics in the workplace and health
Nanoparticles, defined as particles with a diameter less than 100 nm, can be inhaled and enter the body through the lungs. They can also enter the body through the skin or gastrointestinal tract, be transported in blood and the lymphatic system and bypass barriers within the body which are generally impermeable to larger particles. Further, substances adsorbed on the nanoparticles, can be delivered intracellularly or react with cell surface receptors, potentially initiating immune responses.
Immunological effects of nano-sized particles including both inflammation and immunosuppression have been shown in many animal studies. Laboratory studies have shown that some nanoparticles can trigger the production of reactive oxygen species and cause damage to cell membranes and DNA. Nanoplastics have been found in human brains, hearts, lungs, breast milk, placenta and semen. Plastics vary in composition and can include toxic components, for example cadmium pigments are common in plastics. The effects of these nanoparticles on humans are unclear but likely to be variable and will be difficult to evaluate in humans.
Associate Professor Mayur Garg (Northern Health Hospital)
Microplastics and human gut health
Microplastics are ubiquitous in our environment, with evidence to date suggesting that humans ingest microplastics as part of our diet on a daily basis. The incidence and prevalence of multiple gastrointestinal illnesses has risen dramatically over the past 50 years, especially inflammatory bowel disease, disorders of gut-brain interaction, and gastrointestinal cancers. This presentation will discuss the potential link between microplastics and gut health, including putative effects on microbiota, gut immunology and inflammation.
Dr Kirsty Wilson (RMIT University)
Nano and microparticles (polystyrene and silica) interactions with the immune system
Nanoparticles come in many different shapes, sizes and compositions. This plethora of physicochemical properties affects how nanoparticles interact in biological environments, including with cells of the immune system. Solid polystyrene nanoparticles (PSNPs) in the viral to bacterial size range (40nm-1000nm) are an excellent model to study the impact of solid materials in the nano-micro range, such as plastics, on uptake by immune cells as well as downstream effects on inflammation and the immune system in general. PSNPs in the viral size range (40-100nm) by themselves are rapidly taken up by activating immune cells such as dendritic cells, but surprisingly do not induce conventional inflammatory pathways. By themselves these viral sized PSNPs do not induce immune responses, however robust T and B cell responses are seen when PSNPs are used as a vaccine delivery platform. Larger particles (500-1000nm), by themselves are by contrast taken up preferentially by immune cells such a myeloid derived suppressor cells (MDSC) associated with the induction of immune-suppression. This shows that small changes in the nano to micro scale for the size of solid man-made particles such as PSNPs have significant, unique and potentially divergent effects on the immune system.
Presentation not available. Please contact the presenter directly.
Professor Magdalena Plebanski (RMIT University)
Polystyrene nano and microparticles interactions with the lung
Airborne pollution is associated with inflammatory lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). Air pollution consists of both fine (~100-1000 nm) and ultrafine (less than 100 nm) particles. Ultrafine nanoparticles have been identified as a significant risk factor. Very little is known however about how diverse plastic and other man-made polymer nano and microparticles interact with the lung. We have studied the interaction of polystyrene nano and micro particles ranging from 40 nm to 1000 nm with immune cells that control inflammatory immune responses associated with asthma and COPD in the lung. Our studies in animal models show polystyrene particle size dependent effects on immunity and inflammation, and a surprising anti-inflammatory profile for a specific nanoparticle size range, capable of rendering lungs resistant to acute lung inflammation associated with asthma, while maintaining ability to clear viral infections such as influenza.