Injectable Biomaterial Heals Tissue Damage from the Inside

A Novel Approach to Internal Tissue RepairA specially engineered biomaterial capable of traveling through the bloodstream presents a promising less invasive option for reducing inflammation and supporting the natural repair processes in injured tissues. Through extensive testing in animal models, th

A Novel Approach to Internal Tissue Repair

A specially engineered biomaterial capable of traveling through the bloodstream presents a promising less invasive option for reducing inflammation and supporting the natural repair processes in injured tissues. Through extensive testing in animal models, this injectable substance demonstrated clear improvements in tissue recovery following heart attacks in both small rodents and larger mammals. Preliminary experiments further indicated that this same strategy holds potential for addressing other conditions driven by inflammation, such as traumatic brain injuries and pulmonary arterial hypertension.

According to Karen Christman, a professor of bioengineering at the University of California San Diego who led the development team, this biomaterial enables treatment of damaged areas from the inside out, representing an innovative direction in regenerative engineering practices. The research findings appeared in Nature Biomedical Engineering during 2022, produced through collaboration among bioengineers and medical professionals. At that stage, Christman noted that safety and efficacy trials in humans might commence within one to two years.

Addressing Ongoing Challenges in Cardiac Recovery

Heart attacks continue to rank among the leading medical emergencies across the United States, with roughly 785,000 new incidents occurring annually. Blockage of blood supply to the heart often results in injury or death of cardiac tissue. The body's natural response involves creating scar tissue, yet this scar lacks the contractile ability of healthy heart muscle. Over extended periods, such scarring can compromise heart function and lead to congestive heart failure. No standard treatment currently exists that directly regenerates cardiac tissue post heart attack. Standard interventions instead concentrate on reestablishing blood flow, preventing additional harm, and mitigating future risks.

Dr. Ryan R. Reeves, a specialist in cardiovascular medicine at UC San Diego, emphasized that coronary artery disease, acute myocardial infarction, and congestive heart failure represent major ongoing public health burdens. As an interventional cardiologist managing these conditions daily, he expressed strong interest in additional therapies capable of enhancing patient results and alleviating severe symptoms.

Evolution from Direct Hydrogel Application to Vascular Infusion

This development extends prior investigations by Christman's group on a hydrogel derived from the natural extracellular matrix of cardiac muscle tissue. The earlier gel formulation required direct catheter based delivery into affected heart muscle, where it would establish a supportive framework promoting cellular growth and tissue regeneration. A phase one clinical trial for that hydrogel, known as VentriGel, confirmed its safety and feasibility when administered via transendocardial injection to patients experiencing left ventricular dysfunction after heart attacks, although larger studies remain necessary to confirm outcome improvements.

The direct injection technique carries a notable restriction, however, since needle insertion into heart muscle generally precludes immediate post heart attack use due to risks of further damage. This limitation encouraged exploration of an alternative biomaterial suitable for infusion into cardiac blood vessels during angioplasty or stenting procedures, or even via intravenous administration. Martin Spang, the study's primary author who completed his doctorate under Christman in the Shu Chien Gene Lay Department of Bioengineering, explained that the team aimed to create a therapy accessible to hard to reach organs by leveraging the existing bloodstream network supplying those areas.

Advantages of Bloodstream Based Delivery

The vascular delivery method provides significant practical benefits because the biomaterial can distribute more uniformly across affected regions rather than remaining localized to limited injection points. This characteristic proves especially useful after heart attacks when damaged zones may prove challenging to access directly and timing is essential. The published study characterized the substance as an intravascularly infused extracellular matrix material originating from decellularized, enzymatically processed, and fractionated ventricular myocardium. It was engineered to target injured sites by adhering to permeable microvasculature and typically broke down within approximately three days.

Production Process for the Injectable Formulation

Creating the intravenous version began with the previously developed and blood compatible hydrogel. Particle dimensions posed the primary obstacle, as original components proved too large for effective engagement with leaky vessels. Spang addressed this through centrifugal processing of the liquid hydrogel precursor, isolating only the nano scale particles while discarding larger ones. Subsequent steps included dialysis, sterile filtration, and freeze drying. Reconstitution with sterile water transforms the resulting powder into a deliverable biomaterial suitable for intravenous or intracoronary application.

Mechanism of Targeting and Repair

In rodent heart attack models, researchers anticipated the biomaterial would traverse leaky vessels into damaged areas where gaps between endothelial cells commonly appear post injury. Observations revealed an unexpected interaction in which the material bound to endothelial cells, facilitated gap closure, and accelerated vessel healing, thereby diminishing inflammation as a key contributor to ongoing tissue harm. Parallel testing in a porcine heart attack model produced comparable outcomes. In both rats and pigs subjected to induced acute myocardial infarction followed by intracoronary infusion, the biomaterial correlated with decreased left ventricular volumes, better wall motion scores, and gene expression patterns indicative of repair processes alongside reduced inflammation.

Expanding Applications to Additional Conditions

While the primary focus involved cardiac damage, additional rat model experiments provided initial evidence that the biomaterial could address inflamed tissues elsewhere, including traumatic brain injury and pulmonary arterial hypertension. This wider applicability stands out as particularly promising because numerous organs remain difficult to access directly yet receive blood supply through vessels, potentially enabling regenerative approaches for previously challenging injuries. Spang highlighted that although cardiac applications dominated the study, extending biomaterial therapies to other inaccessible tissues could broaden the scope of tissue engineering toward novel disease treatments.

Progress Following the Initial 2022 Publication

Subsequent research has continued examining how extracellular matrix biomaterials support recovery after myocardial infarction. A 2025 investigation in Nature Communications, involving Christman and colleagues, employed spatial transcriptomics and single nucleus RNA sequencing to analyze cellular level effects in rat models. Findings identified beneficial signals related to immune regulation, vascular and lymphatic formation, fibroblast activity, myocardial preservation, smooth muscle proliferation, and nerve tissue development. This work supplemented rather than replaced requirements for clinical evaluation of the intravascular biomaterial while offering deeper insights into healing mechanisms at regional and cellular scales within damaged hearts. Ventrix Bio, the company co founded by Christman, has advanced related cardiac extracellular matrix technologies, including an ongoing phase one safety study in pediatric patients with hypoplastic left heart syndrome sponsored by Emory University, though recruitment had not commenced at the time of review.

Pathway Toward Clinical Evaluation

Christman and Ventrix Bio intend to pursue regulatory approval for human trials of the newer intravascular biomaterial targeting heart conditions. Successful clearance would require demonstration of safety, delivery practicality, and meaningful outcome improvements. The therapy currently remains experimental, yet its non invasive delivery through standard vascular procedures or intravenous routes offers clear appeal for reaching internal injuries effectively. Dr. Reeves noted that a primary goal in managing severe coronary disease and infarction involves preventing progression to ventricular dysfunction and heart failure, positioning this straightforward therapy as a potentially valuable addition to existing treatment strategies.