Stimulation of Odontogenesis and Angiogenesis via Bioactive Nanocomposite Calcium Phosphate Cements Through Integrin and VEGF Signaling Pathways

Abstract

Formulating self-setting calcium phosphate cements (CPCs) with secondary phases particularly in the nanoscale order holds great promise to improve biological properties. Here, we focus on the effect that bioactive glass nanoparticles (BGN) incorporated in CPC compositions can have on the proliferation, odontogenic differentiation, and angiogenic stimulation of stem cells derived from human dental pulp (HDPSCs). These odontogenic and angiogenic events are of special importance in the dentin-pulp regeneration processes. In comparison to pure CPCs, nanocomposite cements exhibit a significantly improved proliferation of HDPSCs, and the improvement is more significant as the BGN content increases. The nanocomposite cements substantially enhance the adhesion of cells, and significantly up-regulate odontogenic differentiation, including alkaline phosphatase (ALP) activity and the expressions of odontogenic genes (sialophosphoprotein, dentin matrix protein I, ALP, osteopontin and osteocalcin). Furthermore, the use of nanocomposite cements result in stimulation of angiogenic gene expression (VEGF, FGF-2, VEGFRs, PECAM-1, and VE-cadherin) and protein production (VEGF, VEGFR-1). The angiogenic stimulation by the HDPSCs significantly affects the endothelial cell behaviors, that is, the endothelial cell migration and the tubular network formation are substantially improved when treated with HDPSC-conditioned medium, particularly with the help of nanocomposite cements. The integrin and VEGF signaling pathways are reasoned for the stimulation of the odontogenesis and angiogenesis of cells, where the nanocomposite cements up-regulate the integrin subsets α1, α2, α3, and β1, and activate the integrin downstream signal pathways, such as p-FAK, p-Akt, p-paxillin, JNK, EK, and NF-κB, as well as other nuclear transcriptional factors, including CREB, STAT-3, and ELK-1. The current results indicate that the new formulation of the nanocomposite self-setting cements might provide some beneficial microenvironments for the regenerative processes of dentin-pulp complex tissues.

Angiogenic properties of dental pulp stem cells conditioned medium on endothelial cells in vitro and in rodent orthotopic dental pulp regeneration

“…The same was demonstrated by Lee et al. [41] where the use of VEGF neutralizing antibody hindered tubular formation of HUVECs incubated with DPSC-CM. Our data showed the ability of CM secreted by SHED to induce the formation of vascular structures.…”

Bioactivity of Bioceramic Materials Used in the Dentin-Pulp Complex Therapy: A Systematic Review

“…All studies comparing a bioceramic material and an additive with the bioceramic material itself showed positive significant results for the bioceramic material in combination with the additive (GNP-CPC, [25]; SC + LLLI, [30]; CPC-BGN, [32]; hTDM/SC, [33]; MTA-CaCl 2 and MTA-Na 2 HPO 4 , [46]), except for one case (MTA+UW/PG, [35]) in which the bioceramic material itself produced better results (Table 8).…”

“…The use of additives in combination with bioceramic materials looks promising, in some cases enhancing or positively influencing the material’s results in bioactivity assays in comparison with the bioceramic material itself. For example, positive significant results have been shown for iron oxide [24], gold [25], and bioactive glass [32] nanoparticles in combination with calcium phosphate. However, we need to interpret these results with caution, being able to extrapolate them to clinical practice only when a clear dosage or ratio for the additive and bioceramic material has been established in controlled clinical trials.…”

<p>RGD- and VEGF-Mimetic Peptide Epitope-Functionalized Self-Assembling Peptide Hydrogels Promote Dentin-Pulp Complex Regeneration</p>

“…Our study is the first to apply a scaffold with a cell adhesion-inducing motif and vascularization motif together to induce pulp regeneration. Other studies have focused on integrin-specific hydrogels functionalized with VEGF for vascularization, 38 , 39 FGF-2 and VEGF functionalization of hydrogels to modulate angiogenesis. 40 In our study, these two motifs concurrently promoted adequate attachment, rapid vascularization and appropriate mineralization during DPC regeneration.…”