Injectable gel could safely repair damaged heart tissue

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Researchers from the University of California (UC) San Diego have developed an injectable hydrogel that could be an effective and safe treatment for tissue damage caused by heart attacks.

Therapies such as the hydrogel would be a welcome development, explained Karen Christman, a professor in the Department of Bioengineering at UC San Diego, since there are an estimated 785,000 new heart-attack cases in the US each year, with no established treatment for repairing damage to cardiac tissue.

According to a statement, the hydrogel is made from cardiac connective tissue that is stripped of heart muscle cells through a cleansing process, freeze dried and milled into powder form and then liquefied into a fluid that can be easily injected into the heart.

Once it hits body temperature, the liquid turns into a semi-solid, porous gel that encourages cells to repopulate areas of damaged cardiac tissue and to preserve heart function, according to Christman.

The hydrogel forms a scaffold to repair the tissue and possibly provides biochemical signals that prevent further deterioration in the surrounding tissues.

‘It helps to promote a positive remodelling-type response, not a pro-inflammatory one in the damaged heart,’ said Christman.

The researchers’ experiments show that the gel can also be injected through a catheter — a method that is minimally invasive and does not require surgery or general anaesthesia.

New, unpublished work by the research team suggests that the gel can improve heart function in pigs with cardiac damage, which brings this potential therapy one step closer to humans, said Christman.

There are few injectable cardiac therapies in development designed to be used in large animals such as pigs, which have a heart that is similar in size and anatomy to the human heart, she explained.

‘Most of the materials that people have looked at have been tested in rats or mice, and they are injectable via a needle and syringe,’ said Christman. ‘However, almost all of them are not compatible with catheter delivery and would gel too quickly, clogging the catheter during the procedure.’

In experiments with rats, the gel was not rejected by the body and did not trigger arrhythmic heart beating, providing some assurance that the gel will be similarly safe for humans.

Christman has co-founded a company, called Ventrix, to bring the gel to clinical trials within the next year.

The study by Christman and colleagues appears in the 21 February issue of the Journal of the American College of Cardiology.