Understanding biological impacts from pollution has become more important as respiratory ailments have increased, as evidenced by the nearly doubling of asthma sufferers since 1980. By learning how particulates travel through the lungs, scientists can design treatments which more precisely target drug delivery for pulmonary diseases. They also can study how pollutants impact lungs of healthy people compared with those who suffer from respiratory ailments.
"We designed a tool that will open up new possibilities for understanding how our environment affects our bodies", stated Rick Corley, principal investigator and a PNNL environmental toxicologist. "The virtual respiratory tract is a major accomplishment in modelling biological systems. It will be the springboard for detailed modelling of the body's organs as a complete system."
Using the virtual respiratory tract, PNNL scientists can analyse the influence of various factors, such as the amount of pollutants or length of exposure, on healthy versus diseased lungs by manipulating the computer model. For example, they can begin to simulate how gases, vapours, and particulates may act differently within lungs of people suffering from cystic fibrosis, emphysema, and asthma.
The model is sufficiently detailed to track individual particles as they move within the rat's respiratory system. In fact, according to Rick Corley, the model's exceptional resolution could drive development or use of new technologies to measure pollutants and their potential impact in the respiratory tract at much greater precision than is currently feasible.
PNNL scientists designed the highly detailed virtual respiratory tract by combining the powerful capabilities of supercomputers, rapid semi-automated computer modelling, and nuclear magnetic resonance (NMR) imaging systems. The equipment is located in the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE user facility located at PNNL.
Creation of PNNL's virtual respiratory tract began in the nuclear magnetic resonance spectrometre facility, which contains instruments capable of producing magnetic resonance images similar to those used in diagnostic medicine but characterised by much higher spatial resolution. With the NMR technology, laboratory scientists captured images of a rat's upper respiratory tract and lungs in unprecedented detail. Then, a semi-automated software package called NWGrid analysed the data, reconstructed it into a computer model and integrated information to show how air flows carrying particles might move inside the imaged respiratory tract during breathing.
"The grid programme allows us to translate raw NMR data into a computer image very quickly", explained Harold Trease, PNNL computational physicist. "We can go from data sets to a working model in hours compared with weeks or months required by other approaches. This increased speed will allow us to replicate the studies many times over, which will give us greater precision, or to broaden our studies and create a database of information on healthy and diseased lungs."
The laboratory's Biomolecular Networks Initiative has supported development of the virtual respiratory tract with about $400.000 over two years. In the upcoming third year of research, scientists will refine the model using data obtained with newly developed NMR imaging techniques. They also will continue to collaborate with other institutions nationwide, including the University of California in Davis, which has conducted extensive research into asthma using animal models, and the University of Washington's pulmonary biology and bio-engineering programmes.
Please, click the following hyperlinks to obtain an idea of the virtual respiratory tract project: