Researchers at CIC biomaGUNE and IBBTEC have developed a protein-engineered iron-based contrast agent for magnetic resonance imaging that detects and slows cardiac fibrosis. In lab-grown 3D human heart tissue, the theranostic agent accumulates in fibrotic areas, generating MRI signal brightness comparable to gadolinium while reducing collagen production and preventing tissue stiffening. The technology offers a safer potential alternative for patients who require repeated scans or cannot receive gadolinium.
Study leadership and publication
- ▪Researchers led by Aitziber L. Cortajarena at CIC biomaGUNE developed a novel iron-based MRI contrast agent that provides both diagnosis and treatment for cardiac fibrosis.
- ▪The study on the iron-based contrast agent was conducted by CIC biomaGUNE in collaboration with Ana Villar's group at IBBTEC and published in Advanced Functional Materials in October 2026.
Mechanisms and burden of cardiac fibrosis
- ▪Cardiac fibrosis occurs when heart repair processes trigger continuous collagen accumulation after cardiac damage, causing the heart to become stiff and impairing pumping function.
- ▪Cardiac fibrosis is a primary driver of heart failure affecting millions globally, yet no approved medical treatment exists specifically to slow its progression.
Limitations of conventional contrast agents
- ▪Patients requiring repeated MRI scans to monitor cardiac fibrosis face heightened risks from long-term accumulation of gadolinium in body tissues.
- ▪Traditional iron-based MRI contrast agents darken damaged tissue images instead of illuminating them, which previously led to the market withdrawal of several iron-based agents.
- ▪Conventional MRI gadolinium contrast agents illuminate damaged heart tissue but carry health risks including long-term tissue retention and usage restrictions in patients with kidney failure.
Design and safety of the new agent
- ▪The CIC biomaGUNE contrast agent utilizes custom-designed proteins that encapsulate iron atom clusters measuring approximately 1.4 nanometers, roughly 50,000 times thinner than a human hair.
- ▪Lead author Lydia Martínez Parra stated that the protein-engineered iron compound exhibits low cell toxicity, releases minimal iron, and is sustainably manufactured in water without toxic reagents.
Engineered 3D cardiac tissue model
- ▪The 3D engineered human cardiac tissue model replicates key features of cardiac fibrosis, including collagen accumulation and increased tissue stiffness.
- ▪Researchers tested the iron-based contrast agent using 3D engineered human cardiac tissue developed from patient cells by Ana Villar's team at IBBTEC.
Diagnostic and therapeutic performance in testing
- ▪In lab-grown human cardiac tissue, the iron-based contrast agent accumulates in fibrotic tissue and generates MRI brightness comparable to gadolinium while increasing signal intensity as fibrosis severity grows.
- ▪The iron-based theranostic agent slows cardiac fibrosis progression in lab-grown tissue by reducing collagen production and storage and preventing tissue stiffening.
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