A special material can be injected into the blood. It moves through the bloodstream and finds damaged heart tissue. The material calms inflammation and lets the heart repair itself.
Scientists tested the material in mice, rats and even in large animals. All of them showed less damage after a heart attack. The same idea might also help with brain injuries and a lung disease called pulmonary arterial hypertension.
"We can treat the injured part of the heart from the inside," said Karen Christman, a bio‑engineer at the University of California, San Diego. "It is a new way to help the heart grow back."
The research was published in *Nature Biomedical Engineering* in 2022. At that time, the team hoped to start human safety tests within a couple of years.
A New Way to Fix a Broken Heart
Every year about 785,000 people in the United States have a heart attack. When blood cannot reach part of the heart, the muscle dies and scar tissue forms. Scar tissue does not contract like healthy muscle, so the heart becomes weaker and may lead to heart failure.
Today, doctors can open blocked arteries and give medicines, but there is no treatment that actually rebuilds heart muscle. Doctors like Ryan Reeves wish for a therapy that can improve recovery and lessen the symptoms of heart failure.
From Gel to Bloodstream Injection
Earlier, Christman's lab created a gel made from the natural framework of heart tissue, called extracellular matrix (ECM). The gel could be injected directly into the heart muscle with a catheter. In a small human trial, the gel was safe, but the injection had to be done weeks after the attack because putting a needle into a fresh wound could cause more damage.
To avoid that problem, the researchers made the material small enough to travel in blood vessels. They spun the gel in a centrifuge, removed big pieces, and kept only nanometer‑sized particles. After drying, the powder can be mixed with sterile water and given through an IV or during a routine heart‑procedure.
Why an IV Is Helpful
Giving the material through the blood lets it spread evenly over the injured area. After a heart attack, tiny gaps appear in the lining of blood vessels. The biomaterial sticks to those gaps, helps close them, and speeds up healing of the vessels. This reduces inflammation, which is a big cause of extra damage.
How the Material Finds the Damage
In mouse experiments, the tiny particles moved through leaky vessels and settled in the damaged tissue. They attached to the vessel walls, sealed the gaps, and encouraged new blood‑vessel growth. The same effects were seen in pig hearts, where the treatment lowered the size of the heart chamber, improved wall movement, and changed genes that control repair.
Beyond the Heart
Because the material uses the bloodstream, it could reach other organs that are hard to get to directly. The scientists tested it in rats with brain injury and with high blood pressure in the lungs, and the early results were promising.
What Has Happened Since 2022
Later studies looked at how the injectable matrix changes gene activity in heart cells. They found it promotes immune balance, new blood‑vessel growth, and even nerve development. A startup called Ventrix Bio continues to develop similar heart‑matrix products and is planning early trials in children with severe heart defects.
Next Steps
For now the therapy is still experimental. The big hope is that doctors could give it during a standard angioplasty or even with a simple IV, letting the material work from inside the blood vessels to repair the heart.