From ABC News in Science, 16 January 2014:
Biodegradable microparticles could dramatically reduce the inflammatory damage that occurs during a heart attack, potentially making the difference between life and death.
The study, conducted on mice, found that the microparticles significantly reduced the amount of scarring in the heart tissue and promoted repair.
The serendipitous discovery was made by an international team of researchers using poly (lactic-co-glycolic) acid microparticles to track an immune cell called an inflammatory monocyte.
These cells are a primitive ‘first responder’ to the site of inflammation, cleaning up dead or dying cells. Unfortunately, they often cause more damage by releasing enzymes and chemicals that also kill off living cells.
“Although the principle behind these inflammatory monocytes is almost certainly one of cleaning up the debris … in heart attack situations, they often come in great floods and do a lot more damage when the blood flow is re-established,” says co-author Professor Nicholas King, Professor of Immunopathology and head of the Department of Pathology at the University of Sydney.
The team noticed that whenever they injected the microparticles, which are ingested by the monocytes, they failed to turn up at the site of the inflammation.
Further investigation revealed that the monocytes changed after ingesting the microparticles.
“They seem to change their phenotype – in other words what they appeared to be and what they appeared to function as – and they started expressing markers on the cell surface that suggest to the body that they are actually dying,” King says.
So instead of heading to the site of inflammation, the monocytes were captured by the spleen, which filters out unhealthy or dying cells from the blood stream. Read more.