The mechanisms of air pollution and particulate matter in cardiovascular diseases

Clinical and epidemiological studies demonstrate that short- and long-term exposure to air pollution increases mortality due to respiratory and cardiovascular diseases. Given the increased industrialization and the increased sources of pollutants (i.e., cars exhaust emissions, cigarette smoke, industry emissions, burning of fossil fuels, incineration of garbage), air pollution has become a key public health issue to solve. Among pollutants, the particulate matter (PM) is a mixture of solid and liquid particles which differently affects human health depending on their size (i.e., PM₁₀ with a diameter <10 μm reach the lung and PM_2.5 with a diameter <2.5 μm penetrate deeper into the lung). In particular, the acute exposure to PM₁₀ and PM_2.5 increases the rate of cardiovascular deaths. Thus, appropriate interventions to reduce air pollution may promote great benefits to public health by reducing the risk of cardiovascular diseases. Several biological mechanisms have been identified to date which could be responsible for PM-dependent adverse cardiovascular outcomes. Indeed, the exposure to PM₁₀ and PM_2.5 induces sustained oxidative stress and inflammation. PM_2.5 is also able to increase autonomic nervous system activation. Some potential therapeutic approaches have been tested both in pre-clinical and clinical studies, based on the intake of antioxidants from dietary or by pharmacological administration. Studies are still in progress to increase the knowledge of PM activation of intracellular pathways and propose new strategies of intervention.