Researchers at Deakin University in Australia have found evidence that particulate matter (PM) from petroleum diesel exhaust is more damaging to human health than that from biodiesel.
Associate Professor Leigh Ackland led a team of researchers who compared the cellular effects of biodiesel emissions particulate matter (BDEP) and petroleum diesel emissions particulate matter (PDEP) using a human airway cell line (A549) in culture.
At concentrations of 25 µg/ml, diesel particulate matter induced the formation of multinucleate cells. In cells treated with a mixture of 80% PDEP:20% BDEP, 52% of cells were multinucleate cells. In cells treated with a mixture of 20% PDEP:80% BDEP, 16% of cells were multinucleate, with a background multinucleate rate of 7%.
These results demonstrate a causal relation between the formation of multinucleate cells and exposure to exhaust particulate matter, in particular diesel exhaust, according to the researchers.
Exposure of A549 cells to PDEP induced apoptosis (structural changes leasing to cellular self-destruction, or “programmed cell death”). The team found that PDEP exhaust was a much stronger inducer of cellular death through apoptosis than BDEP. The researchers suggested that as exposure to diesel exhaust particles is associated with asthma and apoptosis in airway cells, diesel exhaust particles may directly contribute to asthma by inducing epithelial cell death through apoptosis.
Australia’s escalating need for fuel is posing a major health problem. Our research found that the particulate matter from diesel exhaust stimulated a “death pathway” response that the body uses to dispose of damaged cells. This response caused the airway cells to fuse together and die. We saw hardly any cell death after treatment with biodiesel particulates. This study provides clear evidence that diesel exhaust is more harmful to our health than biodiesel exhaust.—Leigh Ackland
Associate Professor Ackland said that the results of the study provide support for calls to move towards replacing gasoline and diesel with cleaner biofuels.
The study has been published in the latest edition of the international journal Immunology and Cell Biology.
Margaret Leigh Ackland, Linda Zou, David Freestone, Simone van de Waasenburg and Agnes A Michalczyk; “Diesel exhaust particulate matter induces multinucleate cells and zinc transporter-dependent apoptosis in human airway cells”; Immunology and Cell Biology advance online publication 7 August 2007; doi: 10.1038/sj.icb.7100109