Pre-vascularized hydrogel co-encapsulating SHEDs and HUVECs for dental pulp regeneration

Rapid reconstruction of the dental pulp vascular network is essential for pulp regeneration. While in vitro pre-vascularization enhances vascularization efficiency, current biomaterial carriers are hampered by issues such as low porosity and poor tissue permeability. This study developed a novel functional vascularized hydrogel using 3D bioprinting combined with in vitro pre-vascularization culture. The hydrogel, based on gelatin methacryloyl (GelMA), was loaded with stem cells from human exfoliated deciduous teeth (SHEDs) and human umbilical vein endothelial cells (HUVECs) at varying ratios. Comprehensive characterization of the hydrogel's physical properties was conducted, and its vascular maturity and ability to induce mineralization were evaluated through a series of in vitro and in vivo experiments. The pre-vascularized hydrogel demonstrated compressive mechanical properties akin to natural dental pulp and displayed favorable degradation rates. Co-cultured SHEDs and HUVECs showed higher proliferation rates compared to monocultures. Notably, the S:H = 1:1 group formed microvascular networks exhibiting enhanced maturity and significantly boosted the osteo/odontogenic differentiation potential of SHEDs. Following a 14-day pre-vascularization period, the pre-vascularized GelMA hydrogel, in combination with human root segments (RS), was implanted subcutaneously into nude mice for an 8-week duration. The pre-vascularized hydrogel group demonstrated markedly enhanced microvascular formation and pulp-like tissue regeneration compared to the non-pre-vascularized control group. These findings underscore the potential of this pre-vascularized hydrogel approach as a novel strategy for expeditious vascularization in pulp tissue regeneration engineering, offering significant clinical implications.