Regeneration of dental pulp after pulpotomy by transplantation of CD31-/CD146- side population cells from a canine tooth

Aim: To achieve complete regeneration of dental pulp in vivo by stem/progenitor cells obtained from a fraction of side population (SP) cells from canine pulp. Materials & methods: A subfraction of SP cells, CD31(-)/CD146(-)SP cells, were isolated by flow cytometry from canine dental pulp. The efficiency of this subfraction of SP cells was evaluated in an experimental model of pulp injury in the dog. Results: The fractionated SP cells formed extensive networks of tube-like structures in vitro. Transplantation of the SP cells into an in vivo model of amputated pulp resulted in complete regeneration of pulp tissue with capillaries and neuronal cells within 14 days. Gene-expression studies demonstrated the expression of pro-angiogenic factors, implying trophic action on endothelial cells. Conclusions: This investigation demonstrates the potential utility of fractionated SP cells as a source of cells for total pulp regeneration complete with angiogenesis and vasculogenesis.