3D-printing hydrogel programmed released exosomes to restore aortic medial degeneration through inhibiting VSMC ferroptosis in aortic dissection.

Aortic dissection (AD) is a devastating disease with a high mortality rate. Exosomes derived from mesenchymal stem cells (exo-MSCs) offer a promising strategy to restore aortic medial degeneration and combat ferroptosis in AD. However, their rapid degradation in the circulatory system and low treatment efficiency limit their clinical application. Methylacrylated gelatin (Gelma) was reported as a matrix material to achieve controlled release of exosomes. Herein, exo-MSCs-embedded in Gelma hydrogels (Gelma-exos) using ultraviolet light and three-dimensional (3D) printing technology. These Gelma-exos provide a sustained release of exo-MSCs as Gelma gradually degrades, helping to restore aortic medial degeneration and prevent ferroptosis. The sustained release of exosomes can inhibit the phenotypic switch of vascular smooth muscle cells (VSMCs) to a proliferative state, and curb their proliferation and migration. Additionally, the 3D-printed Gelma-exos demonstrated the ability to inhibit ferroptosis in vitro, in vivo and ex vivo experiments. In conclusion, our Gelma-exos, combined with 3D-printed technology, offer an alternative treatment approach for repairing aortic medial degeneration and ferroptosis in AD, potentially reducing the incidence of aortic dissection rupture.