Nanoparticles provide a new way to treat heart attack

Microparticles 200 times smaller than the thickness of a human hair are being used in a new nanobiological approach that may transform the way heart attacks and cardiovascular disease is treated.

Discovered by researchers at the University of Sydney and Macquarie University in collaboration with researchers at the US-based Northwestern University, the University of Bonn and the University of Münster in Germany, the technique involves injecting the tiny microparticles into the bloodstream within 24 hours of a heart attack.

The immune-modifying microparticles are taken up by inflammatory monocytes - most of the damage to heart muscle after a heart attack is caused by these inflammatory monocytes that are trafficked to the site of the oxygen-starved tissue.

But the microparticles cause the monocytes to divert to the spleen where they undergo apoptosis. The researchers found that injecting the microparticles reduced the tissue damage to heart muscle by half, boosting heart function and reducing heart scarring.

Nicholas King, Professor of Immunopathology at the University of Sydney and co-discoverer of the approach, 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 potential beyond the cardiovascular system.

The research shows the microparticles reduce inflammatory damage and enhance tissue repair in mouse models for 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.

The next step will be to conduct safety tests on the microparticles, which 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 are expected to follow at the University of Sydney within two years.

The research was recently published in Science Translational Medicine.