Microparticles Embedded With Drugs Reduce Scarring in Rats' Hearts

An Indian-origin researcher has created tiny polymer beads that can slowly release anti-inflammatory drugs, and break down into non-toxic components.

Tiny polymer beads that can slowly release anti-inflammatory drugs, and break down into non-toxic components have been developed by an Indian-origin researcher.

Dr. Niren Murthy's beads have been tested by researchers at Emory University and Georgia Institute of Technology on rats, with some promising results.

Heart Attack - Overview
Heart attack is the death of the heart muscle due to loss of blood supply. Heart disease is the leading cause of death in the United States. Other names for heart attack include acute myocardial infarction, coronary thrombosis, and coronary occlusion.

The researchers injected them into rats' hearts after a simulated heart attack, and found that the drug-embedded "microparticles" reduce inflammation and scarring.

According to them, injecting the particles could cut the area of scar tissue formed after the heart attack in half, and boost the ability of the heart to pump blood by 10 percent weeks later.

"If you look at previous studies to see what it would take to get enough of these drugs into the heart, they did things like direct injections twice a day. And there are clear toxicity issues if the whole body is exposed to the drug," Nature Materials quoted Dr. Michael Davis, assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, as saying.

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The researcher has revealed that the team turned to Murthy's microscopic particles, made of a material called polyketals, as an alternative.

He says that the microparticles break down over a few weeks in the body, releasing the experimental drug SB239063, which inhibits an enzyme called MAP kinase, which is important during the damaging inflammation that occurs after a heart attack.

Angioplasty
Arteries supplying the heart is sometimes blocked by plaque leading to heart attack.Angioplasty is a method by which a part of the blocked artery is expanded to place a stent.Once this is done normal blood flow resumes and the heart regains its normal function.

Davis adds that the drug gradually leaches out of the polyketal particles - half is gone after a week of just sitting around in warm water.

The microparticles are also broken down by white blood cells called macrophages, the researcher says.

Animation of heart attack symptoms
Heart attack can cause symptoms such as Chest pain or discomfort, Shortness of breath and pain in neck, back, arm, or shoulder and is due to blockage of blood supply to the heart muscles

"These are actually cells we're trying to reach with the drug, because they're involved in the inflammatory response in the heart. The macrophages can surround and eat the particles, or fuse together if the particles are too big," he says.

Davis points out that polyketals have an advantage over other biodegradable polymers, in that they break down into neutral, excretable compounds that are not themselves inflammatory.

He highlights the fact that the main effect of using the particles was that it prevented the heart from the scarring, which sets in after the initial tissue damage of a heart attack.

He and Murthy are exploring polyketal particles as delivery vehicles for drugs or proteins in several organs: heart, liver, lungs and spinal cord.

Source-ANI
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