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

Abstract Introduction Transplantation of dental pulp stem cells (DPSCs) has emerged as a novel strategy for the regeneration of the lost dental pulp after pulpitis and trauma. The dental pulp regeneration of the young permanent tooth with 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 remain difficult in the clinic. How to promote vascular reconstitution is essential for the survival of stem cells and regeneration of dental pulp after transplantation into the adult tooth. Methods Adipose tissue-derived microvascular fragments (ad-MVFs) were isolated from human adipose tissues. 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 (hTRSs) and implanted subcutaneously into immunodeficient mice. Regenerated pulp-like tissues were analyzed by hematoxylin and eosin (H&E) and immunohistochemistry. The vessels in regenerated tissues were analyzed by Micro-CT and immunofluorescence. Results The 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-week implantation. Supplementation of ad-MVFs led to more odontoblast-like cells and increased formation of mineralized substance around the root canal. Conclusions Co-transplantation with ad-MVFs promotes the angiogenesis and revascularization of transplanted DPSCs aggregates, leading to robust regeneration of dental pulp.