MSU Scientists Develop First Human Heart Organoid to Study Atrial Fibrillation

Researchers at Michigan State University (MSU) have created the first human heart organoids capable of replicating atrial fibrillation (A-fib), a condition affecting approximately 60 million people worldwide. This innovative development addresses a significant gap in cardiovascular research, as no new drugs for A-fib have been introduced in over 30 years. The organoids, which are tiny, functional models of human organs, allow for unprecedented studies of heart development, diseases, and drug responses.

MSU scientists create first human heart organoid to replicate A-fib

The project, led by Aitor Aguirre, an associate professor of biomedical engineering, began in 2020. Aguirre's team utilized donated human stem cells to create these organoids, which are roughly the size of a lentil and feature chamber-like structures and vascular networks. The latest advancement involved the addition of immune cells, specifically macrophages, to the organoids, enhancing their physiological accuracy. This modification enabled researchers to induce inflammation, mimicking the conditions that lead to A-fib.

MSU scientists create first human heart organoid to replicate A-fib

Colin O’Hern, an MSU osteopathic medicine student, highlighted the significance of this model, stating, “Our new model allows us to study living human heart tissue directly, something that hasn’t been possible before.” The team demonstrated that introducing inflammatory molecules caused the heart cells to beat irregularly, while an anti-inflammatory drug partially restored normal rhythm.

MSU scientists create first human heart organoid to replicate A-fib

The creation of these organoids is expected to facilitate the development of new therapies for A-fib. Aguirre noted that existing treatments often target symptoms rather than the underlying mechanisms of the disease. He stated, “This new model can replicate a condition that is at the core of many people’s medical problems,” suggesting that it could accelerate the introduction of safer and more effective drugs into the market.

MSU scientists create first human heart organoid to replicate A-fib

The research findings, published in the journal *Cell Stem Cell*, indicate that the organoids can be aged to resemble adult hearts, further enhancing their utility in testing therapies for inflammation-driven heart conditions. Aguirre emphasized the potential of these organoids to modernize translational research and improve preclinical testing predictivity.

MSU scientists create first human heart organoid to replicate A-fib

MSU researchers are collaborating with pharmaceutical and biotech companies to screen compounds that could prevent arrhythmias without causing heart damage. Aguirre's team has established MSU as a leader in human heart organoid research, with plans to develop personalized heart models derived from patient cells for precision medicine and eventually create transplant-ready heart tissues.

MSU scientists create first human heart organoid to replicate A-fib

While the advancements in organoid technology are promising, some experts caution that translating findings from organoids to actual human treatments can be complex. The efficacy of therapies tested on organoids may not always correlate with outcomes in human patients, necessitating further validation.

MSU scientists create first human heart organoid to replicate A-fib

• “When we added inflammatory molecules, the heart cells began beating irregularly. Then we introduced an anti-inflammatory drug, and the rhythm partially normalized. It was incredible to see that happen.” — Colin O’Hern, MSU Osteopathic Medicine Student

MSU scientists create first human heart organoid to replicate A-fib

• “Our longer-term vision is to develop personalized heart models derived from patient cells for precision medicine and to generate transplant-ready heart tissues one day,” — Aitor Aguirre, Associate Professor of Biomedical Engineering

MSU scientists create first human heart organoid to replicate A-fib

The development of these heart organoids marks a significant step forward in cardiovascular research, with the potential to transform the landscape of A-fib treatment and improve patient outcomes.

MSU scientists create first human heart organoid to replicate A-fib