Revascularization of Human Dental Pulp - The clinical reality

Aim: of this study was to investigate the angiogenic potential of human dental pulp stromal cells (HDPSCs) and stro-1 positive populations as well as their role in tissue regeneration – the clinical reality. . Methods: HDPSC were isolated by collagenase digestion (from three different donors). STRO-1 positive cells were enriched using fluorescence activated cell sorting (FACS) with monoclonal anti- STRO-1 and anti- CD45 PE conjugated antibodies. Cells from passage 4 cultured as monolayers or on 3D Matrigel scaffold in endothelial cell growth medium-2 (EGM-2) with/without 50ng/mL of vascular endothelial growth factor (VEGF). Cells cultured in á-MEM were used as controls. After 24, 48 and 72 hours, Angiogenic markers(CD31, CD34, vWF and VEGFR-2) expression was determined by qRT-PCR and immuno-histochemistry. The dental pulp space of root fragments were filled with mixture of HDPSCs and Matrigel and implanted subcutaneously in nude mice. Results: Both HDPSCs and STRO-1+/CD45- cells cultured as monolayer in EGM-2 with VEGF showed up regulation of CD31 and VEGFR-2 expression compared to the control group while expression of CD34 and vWF remained unaffected. However on Matrigel, all four genes were up regulated to different extents. Changes in gene expression in both cell types were time dependent. Immuno-histochemical staining confirmed that the HDPSCs cultured in the test group showed positive staining for CD31, CD34 vWF and VEGFR-2 when grown in both monolayer and 3D Matrigel culture compared to control cultures. When cultured on Matrigel (but not Monolayer) for 7 days, HDPSC formed tube-like structures in the VEGF treated group. In vivo results showed early blood vessel formation as proved by staining positively with CD34, CD31 and VEGFR-2. Conclusion: HDPSCs and STRO-1+/CD45- population have the potential to be used for angiogenesis together with stem cell based therapy for revascularization of dental pulp tissue in the clinical setting.