First human tissue model of inherited heart disease could unlock new treatments

Scientists at Washington University in St. Louis have created the first human model of desmin-related cardiomyopathy (DRM), a rare inherited heart disease with no disease-specific treatments. Using induced pluripotent stem cells (iPSCs) with a genome-edited mutation and micro-engineered heart tissues, the team replicated key features of the disease at protein levels that closely mirror those in the actual human body — something previous animal models couldn't achieve.

The miniaturized tissues, which experience real mechanical forces just like a beating heart, revealed that the mutant CRYAB protein causes desmin to clump abnormally inside heart muscle cells. The team also discovered that these aggregates disrupt calcium handling — a finding with broader implications for understanding what happens to heart cells after a heart attack.

Key Takeaways:

• The engineered tissue model expressed desmin at physiologically relevant levels, overcoming a major limitation of prior mouse models
• Desmin aggregation alone didn't fully explain reduced contractility — impaired calcium handling was also identified as a key contributing factor
• A JAK-STAT pathway inhibitor previously shown to clear aggregates in rat cells failed to fully rescue function in the human tissue model, underscoring the importance of human-relevant systems for drug testing

Why it matters: DRM affects roughly 1 in 2,000 people and currently has no targeted therapies. This new human tissue model gives researchers a far more accurate tool to study the disease and screen potential treatments — and its insights into desmin mislocalization may also shed light on more common causes of heart failure, including post-heart attack damage.