Repairing the Heart from the Inside Out: The Rise of IV-Injectable Biomaterials
Heart attacks remain one of the most critical medical emergencies in the United States, with an estimated 785,000 new cases occurring each year. While modern medicine is excellent at restoring blood flow during an emergency, the aftermath is a different story. When cardiac tissue dies, the body replaces it with scar tissue. Unlike healthy heart muscle, this scar cannot contract, which often weakens the heart over time and leads to congestive heart failure.
Until now, there has been no established therapy to directly repair this damaged tissue. However, a breakthrough in regenerative engineering from the University of California San Diego (UC San Diego) is changing the approach. Researchers have developed an injectable biomaterial that travels through the bloodstream to treat damaged tissue from the inside out.
The Limitation of Current Heart Repair
Existing care for heart attack patients focuses on limiting further injury and managing future risks. The primary challenge is that once the heart muscle is damaged, it doesn’t naturally regenerate. This creates a significant burden on public health.
“Coronary artery disease, acute myocardial infarction, and congestive heart failure continue to be the most burdensome public health problems affecting our society today,” said Dr. Ryan R. Reeves, a physician in the UC San Diego Division of Cardiovascular Medicine. “As an interventional cardiologist… I would love to have another therapy to improve patient outcomes and reduce debilitating symptoms.”
From Direct Injection to Bloodstream Infusion
This new technology builds on previous research involving a hydrogel made from the extracellular matrix (ECM)—the natural biological scaffolding that surrounds heart cells. An earlier version of this technology, known as VentriGel, required a catheter to inject the gel directly into the heart muscle. While a 2019 phase 1 human clinical trial found that this transendocardial injection was safe and feasible for patients with left ventricular dysfunction, the method had a major drawback: it couldn’t be used immediately after a heart attack because the needle could cause additional injury.
To solve this, the research team, led by Professor of Bioengineering Karen Christman, developed a version that could be delivered via an IV or infused into a coronary artery during procedures like stenting or angioplasty.
“We sought to design a biomaterial therapy that could be delivered to difficult-to-access organs and tissues, and we came up with the method to take advantage of the bloodstream,” explained Martin Spang, the study’s first author and a Ph.D. From the Shu Chien-Gene Lay Department of Bioengineering.
How the Biomaterial Works
The transition from a thick gel to an injectable fluid required a precision engineering process. The team used a centrifuge to separate the hydrogel’s liquid precursor, removing large particles and keeping only nano-sized particles. This material was then dialyzed, sterile filtered, and freeze-dried into a powder that becomes a biomaterial when sterile water is added.
The “Leaky Vessel” Target
The biomaterial is designed to find injured tissue automatically. After a heart attack, the endothelial cells lining the blood vessels develop gaps, making the vessels “leaky.” The researchers discovered that the biomaterial doesn’t just move through these gaps; it actually attaches to the endothelial cells and helps close them.
This process speeds up the healing of blood vessels and reduces inflammation, which is one of the primary drivers of tissue damage following an injury.
Evidence and Results
The effectiveness of this approach has been documented across several studies:
- 2022 Nature Biomedical Engineering Study: In rodent and porcine (pig) models, intracoronary infusion of the biomaterial led to reduced left ventricular volumes, improved wall motion scores, and gene expression changes that signaled tissue repair and reduced inflammation.
- 2025 Nature Communications Study: Using spatial transcriptomics and single nucleus RNA sequencing, researchers found that these ECM biomaterials trigger pro-repair signals. These include immune modulation, the development of blood vessels and lymphatics, myocardial salvage, and neurogenesis in rat models.
Potential Beyond the Heart
While the primary focus is cardiac repair, the ability to use the bloodstream as a delivery route opens doors for other conditions. Because almost every organ is supplied by blood vessels, this “inside out” approach could be applied to other inflammation-driven injuries. Early proof-of-concept experiments in rat models suggest the material could one day treat traumatic brain injury and pulmonary arterial hypertension.
The Path to Human Treatment
The technology is currently moving toward clinical application through Ventrix Bio, Inc., a startup co-founded by Karen Christman. The company is planning to seek FDA authorization to study the intravascular biomaterial in humans.
a ClinicalTrials.gov listing indicates a phase 1 open-label study sponsored by Emory University to assess the safety and feasibility of intramyocardial injection of Ventrix Bio’s ECM material in children with hypoplastic left heart syndrome.
Key Takeaways for Patients and Providers
| Feature | Traditional Hydrogel | New Intravascular Biomaterial |
|---|---|---|
| Delivery Method | Direct needle injection (Catheter) | IV or Coronary Infusion |
| Timing | Delayed (to avoid further injury) | Potential for immediate post-attack use |
| Distribution | Localized to injection sites | Spreads evenly through damaged tissue |
While this treatment remains experimental, it represents a shift in regenerative medicine. By leveraging the body’s own vascular network, doctors may soon be able to deliver repair materials to the most damaged parts of the heart and brain without the need for invasive surgery.