Negatively charged microparticles potentially could reduce damage from heart attacks, a Chicago-Australia team reported in a study on mice published Wednesday.
Researchers from Northwestern University and the University of Sydney in Australia found that injecting mice with the microparticles within 24 hours of a heart attack reduced tissue damage by 40-50 percent. The study, published in Science Translational Medicine, showed similar results for West Nile virus, multiple sclerosis, inflammatory bowel disease and other issues.
"We're pretty optimistic because of the very potent anti-inflammatory effects we've seen," said Stephen Miller, a researcher and professor of immunobiology from Northwestern University.
The Centers for Disease Control and Prevention reported that heart disease is the No. 1 cause of death in the U.S. In 2009, nearly 25,000 people in Illinois died from heart disease.
One of the researchers, Daniel Getts, a visiting scholar in microbiology-immunology at Northwestern, compared a heart attack to frozen pipes in the winter. "There's no water getting through and on the other side of the blockage the heart starts to die," he said.
The blockage causes tissue to die and the body responds by sending white blood cells to clean up the dead tissue cells. However, the white blood cells become inflamed and can cause damage.
In the study, the charged microparticles were injected into the bloodstream and bonded with the inflammatory cells.
"Instead of going to the heart or the brain, they were diverted to the spleen by the cells that ingested them," Miller said. "A good proportion of those cells end up dying."
By injecting people with microparticles soon after a heart attack, researchers hope they can minimize damage caused by inflammatory cells.
The microparticles are made from a biodegradable polymer known as poly (lactic-co-glycolic) acid. The Food and Drug Administration already has approved the particles, which are used to make some medical sutures. Scientists do not yet understand what causes the particles to redirect the inflammatory cells to the spleen, or how they signal the cells to die.
"There needs to be future work on how these particles are manipulating the immune system," said Eric Bachelder, a researcher in drug delivery at Ohio State University in Columbus. He called the treatment both innovative and promising.
"If you told me someone injected it into these animal models...I would have thought that nothing would have happened," Bachelder said of the microparticles
The study was conducted on thousands of mice in labs in Chicago and Sydney, and Miller said much of its promise lies in the successful replication of the experiments.
"The cool thing I think about the study is that this was a collaboration between labs in Australia and at Northwestern, and the various models were carried out at different places," he said.
According to Miller, a biotech company called Cour Pharmaceutical Development Co. has been spun off of the experiment to raise capital for a clinical trial focusing on heart attack treatment. Getts is Cour's chief scientific officer and Miller has an interest in the company. The therapy will need to go to the FDA for approval of a phase one trial in humans, which could happen within the next two years.
"The bottom line is this seems to be a very potent protective therapy for different inflammatory disease models," Miller said.