Lymphatics-epicardial cross talk via Reelin controls cardiac growth.

Cardiac lymphatics regulate embryonic heart growth through Reelin-mediated epicardial signaling, influencing organ size by controlling Wt1 and Igf1 pathways.

• Why it matters: Understanding how organ size is precisely controlled is crucial for addressing congenital heart defects and developing regenerative therapies, yet the mechanisms remain poorly defined.
• What they did: The study combined single-cell RNA sequencing with loss- and gain-of-function mouse models and human epicardial organoids to investigate the regulatory network involving cardiac lymphatics, Reelin, Wt1, and Igf1 signaling.
• The result: Findings reveal that cardiac lymphatics serve as a physiological quality control for heart growth via Reelin-dependent epicardial activation, enabling potential strategies for cardiac repair and growth regulation.