Inactivation of serum paraoxonase by diesel exhaust: Implication of environmental pollution on risk of cardiovascular disease

Cardiovascular diseases (CVD) are among the major killer diseases affecting men and women of productive age all over the world. A major mechanism responsible for the onset of the disease is oxidative stress leading to modification of low density lipoprotein. Oxidative stress can also inactivate high density lipoproteins (HDL), the only negative risk factor of CVD. Oxidation of HDL causes loss of activity of the HDL-associated antioxidant enzyme paraoxonase. Diesel exhaust of vehicles inhibited serum PON activity in a dose dependent manner. Inactivation was proportional to the capacity of the diesel engine. Petrol vehicle exhaust did not inactivate PON activity. Diesel Exhaust contains particles of size < 10nm which are collectively called as respirable suspended particles (RSPM). RSPM may contain free radicals and pro oxidants and thus cause oxidative inactivation of biomolecules. Thus Diesel Exhaust may be an added risk factor for the development of CVD