Adipose Tissue–derived Microvascular Fragments as Vascularization Units for Dental Pulp Regeneration

Abstract

IntroductionThe transplantation of dental pulp stem cells (DPSCs) has emerged as a novel strategy for the regeneration of lost dental pulp after pulpitis and trauma. Dental pulp regeneration of the young permanent tooth with a wide tooth apical foramen has achieved significant progress in the clinical trials. However, because of the narrow apical foramen, dental pulp regeneration in adult teeth using stem cells remains difficult in the clinic. Finding out how to promote vascular reconstitution is essential for the survival of stem cells and the regeneration of dental pulp after transplantation into the adult tooth. MethodsAdipose tissue–derived microvascular fragments (ad-MVFs) were isolated from human adipose tissues. The apoptosis and senescence of DPSCs cultured in conditioned media were evaluated to explore the effects of ad-MVFs on DPSCs. DPSCs combined with ad-MVFs were inserted into the human tooth root segments and implanted subcutaneously into immunodeficient mice. Regenerated pulplike tissues were analyzed by hematoxylin and eosin and immunohistochemistry. The vessels in regenerated tissues were analyzed by Micro-CT and immunofluorescence. ResultsThe isolated ad-MVFs contained endothelial cells and pericytes. ad-MVFs effectively prevented the apoptosis and senescence of the transplanted DPSCs both in vivo and in vitro. Combined with DPSCs, ad-MVFs obviously facilitated the formation of vascular networks in the transplants. DPSCs combined with ad-MVFs formed dental pulp–like tissues with abundant cells and matrix after 4 weeks of implantation. The supplementation of ad-MVFs led to more odontoblastlike cells and increased the formation of mineralized substance around the root canal. ConclusionsCotransplantation with ad-MVFs promotes the angiogenesis and revascularization of transplanted DPSC aggregates, leading to robust regeneration of dental pulp.