Scientists led by Aitor Aguirre at Michigan State University have produced the first functioning human heart‑like organoids that model atrial fibrillation. The three‑dimensional structures, about the size of a lentil, beat rhythmically and contain chamber‑like spaces plus an internal vascular network of arteries, veins and capillaries. The organoids are assembled from donated human stem cells and, in the latest work, immune cells were incorporated to better mimic real heart tissue.
Colin O’Hern, a physician‑scientist student, added macrophages and other innate immune cells that normally help guide heart growth. The researchers induced inflammation in the organoids and reproduced an irregular heartbeat similar to A‑fib. When they introduced an anti‑inflammatory drug the rhythm partially normalized, showing the model can reveal disease mechanisms and test therapies. The team also developed a method to age the organoids toward adult‑like hearts by exposing them to inflammation linked to A‑fib.
Aguirre says the immune cells make the models more physiologically accurate and should speed therapeutic development. The work involves contributors from Michigan State and Washington University and is supported by the National Institutes of Health, the National Science Foundation, Corewell Health and several foundations and associations. The group is now working with pharmaceutical and biotech partners to screen compounds for effects on arrhythmia and heart safety.
- Longer‑term goals include personalized heart models from patient cells.
- The team also aims to generate transplant‑ready heart tissues in the future.
Difficult words
- organoid — small laboratory-grown structure that mimics an organorganoids
- atrial fibrillation — rapid, irregular heartbeat originating in heart atria
- macrophage — large immune cell that engulfs pathogens and debrismacrophages
- inflammation — body's response to injury or infection causing swelling
- vascular network — system of blood vessels in an organ
- stem cell — unspecialized cell that can become other cellsstem cells
- arrhythmia — abnormal heart rhythm or heartbeat pattern
- personalized — designed from a specific patient's cells or data
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How might personalized heart models from patient cells change treatment for people with atrial fibrillation? Give reasons or examples.
- What are the advantages and limitations of using organoids to test new drugs compared with animal studies?
- What ethical or practical challenges could arise when researchers try to create transplant-ready heart tissues?
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