Endothelialized callus organoids drive rapid regeneration of critical-size segmental long bone defects.

Endothelialized callus organoids enable rapid regeneration of critical-size tibial defects in mice.

• Why it matters: Large bone defects are difficult to treat with current methods, which often fail to restore full functionality, highlighting the need for improved regenerative approaches.
• What they did: Researchers engineered human endothelialized callus organoids (hECOs) by co-culturing skeletal progenitors with endothelial cells, resulting in callus-like structures that promote vascularization and bone regeneration in mice.
• The result: The hECOs supported swift host vascularization and bone repair, with donor cells initially contributing to regeneration but later being replaced, suggesting they act as transient templates for host-driven healing.