Stem/Progenitor Cells from Inflamed Human Dental Pulp Retain Tissue Regeneration Potential

TLDR

Dental pulp stem cells (DPSCs) have been isolated from normal human pulps, but it is unclear whether they are present in inflamed pulps. The study aimed to determine whether DPSCs can be identified and isolated from inflamed pulps and whether they retain tissue regeneration potential when cultured. DPSCs were isolated from freshly collected normal and inflamed pulps, characterized in vitro, and their regenerative capacity tested in an in vivo mouse model. Inflamed pulps expressed higher mesenchymal stem cell markers and IP‑derived DPSCs showed similar marker profiles but reduced proliferation and mineralization in vitro; nevertheless, they formed pulp/dentin complexes comparable to normal DPSCs in mice, indicating retained regenerative potential in some samples.

Abstract

Background: Potent stem/progenitor cells have been isolated from normal human dental pulps termed dental pulp stem cells (DPSCs). However, it is unknown whether these cells exist in inflamed pulps (IPs). Aims: To determine whether DPSCs can be identified and isolated from IPs; and if they can be successfully cultured, whether they retain tissue regeneration potential in vivo. Materials & methods: DPSCs from freshly collected normal pulps (NPs) and IPs were characterized in vitro and their tissue regeneration potential tested using an in vivo study model. Results: The immunohistochemical analysis showed that IPs expressed higher levels of mesenchymal stem cell markers STRO-1, CD90, CD105 and CD146 compared with NPs (p < 0.05). Flow cytometry analysis showed that DPSCs from both NPs and IPs expressed moderate to high levels of CD146, stage-specific embryonic antigen-4, CD73 and CD166. Total population doubling of DPSCs-IPs (44.6 ± 2.9) was lower than that of DPSCs-NPs (58.9 ± 2.5) (p < 0.05), and DPSCs-IPs appeared to have a decreased osteo/dentinogenic potential compared with DPSCs-NPs based on the mineral deposition in cultures. Nonetheless, DPSCs-IPs formed pulp/dentin complexes similar to DPSCs-NPs when transplanted into immunocompromised mice. Conclusion: DPSCs-IPs can be isolated and their mesenchymal stem cell marker profiles are similar to those from NPs. Although some stem cell properties of DPSCs-IPs were altered, cells from some samples remained potent in tissue regeneration in vivo.