Analysis of Potential Mutagenic Effects of World Trade Center Dust on in Vitro Systems

Ever since the 1950s, air pollution has been linked to decreased lung function and increased cancer risk. Air pollution can consist of natural or artificial materials that range in chemical as well as physical properties. Inhaled pollutants can have a variety of effects on organisms ranging from minor irritation, to chronic obstructive pulmonary disease, and even cancer or death. Historically, it has been noted that increased levels of air pollution are associated with decreases in human health and increases in mortality. Following the World Trade Center tragedy, rescue workers as well as New York City residents were exposed to thousands of tons of particulate matter that was inhaled and ingested over an extended period of time. Some of the immediate effects of these pollutants included “World Trade Center Cough,” a condition that resulted in increased coughing, respiratory pathway irritation, and decreases in lung function. Though there are several known carcinogens found within the heterogeneous mixture of particles that make up World Trade Center dust, there is currently no link between World Trade Center dust inhalation and cancer development. Furthermore, the molecular processes responsible for “World Trade Center Cough” are not completely understood. There are a variety of mechanisms that could be responsible for the decreased lung function reported in World Trade Center rescue workers. It is possible that just the presence of particulate matter in the lungs may lead to an inflammatory response that is powerful enough to induce cell damage and subsequent tissue damage and loss of function. Particles can damage cell membranes, inducing necrosis and resulting in the spilling of cellular contents into the surrounding environment and inducing inflammatory responses. Damage could also occur in response to the chemical properties of inhaled particles. Particle components can be reactive and interact with DNA to induce mutation and even the occurrence of cancer. This study investigated the physical and chemical properties of World Trade Center dust using in vitro methods. Human lung fibroblast cells (MRC-5 and WI-38) were exposed to various concentrations of World Trade Center dust and controls to simulate the World Trade Center dust exposure in in vivo lung systems. Proliferation and apoptosis rates were measured in cells exposed to various concentrations of World Trade Center dust and controls in order to elucidate any physical or chemical interactions between cells and particles that may decrease cell viability and induce injury or mutation. An Ames assay was performed to determine mutagenic effects that various concentrations of World Trade Center dust may have on living systems. Mutations incurred by Salmonella typhimurium cells suggested the possibility that World Trade Center dust is mutagenic. Analysis of proliferation and apoptosis in cells exposed to World Trade Center dust, in conjunction with an Ames assay, allowed for a better understanding of the risks faced by rescue workers and other personnel exposed to varying quantities of particulate matter pollution following the collapse of the World Trade Center