The power of microparticles

A University of Sydney discovery has the potential to transform the treatment of a heart attack, after a new approach boosted heart function and reduced heart scarring in preclinical studies.

The research breakthrough, published in Science Translational Medicine, involves injecting tiny "microparticles" into the bloodstream within 24 hours of a heart attack to reduce tissue damage made by inflammatory cells.

The discovery was made at the University of Sydney and is the result of an international collaboration with researchers at Northwestern University in the USA, and Bonn and Münster in Germany.

After a heart attack (myocardial infarction), much of the damage to heart muscle is caused by inflammatory cells that rush to the scene of the oxygen-starved tissue. But researchers found this damage was slashed in half when they used the microparticles to keep the highly damaging cells away.

"This is the first therapy that specifically targets a key driver of the damage that occurs after a heart attack," said Dr Daniel Getts, one of the original discoverers from the University of Sydney, now based at Northwestern University in the USA.

"There is no other therapy on the horizon that can do this. It has the potential to transform the way heart attacks and cardiovascular disease is treated," he said.

Nicholas King, Professor of Immunopathology at the University of Sydney and co-discoverer, said the power of the treatment was that the microparticles triggered a natural pathway that destroyed the inflammatory cells.

"We're very excited," Professor King said.

"This discovery means that we can prevent major tissue damage simply because the inflammatory cells pick up microparticles in the blood stream and are then diverted down a natural cell disposal pathway into the spleen."

The discovery also has huge potential beyond the cardiovascular system.

The research shows the microparticles reduce inflammatory damage and enhance tissue repair in disease models as diverse as multiple sclerosis, inflammatory bowel disease, peritonitis, viral inflammation of the brain and kidney transplant.

"The potential for this approach is quite extraordinary," Professor King said.

"It's amazing that such a simple approach can limit major tissue damage in such a wide range of diseases."

The next step is safety tests on the microparticles, which are tiny balls of absorbable material, 200 times smaller than the thickness of a human hair. They are made of a biodegradable compound, poly lactic-co-glycolic acid, used in absorbable surgical sutures and already approved for use in humans.

Clinical trials on heart attack patients should follow within two years at the University of Sydney.

The research was co-authored by Professor King from the University of Sydney, and Dr Getts and Professor Miller from Northwestern University.

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