Hyaluronic acid hydrogels incorporating platelet lysate enhance human pulp cell proliferation and differentiation

Abstract

The restoration of dentine-pulp complex remains a challenge for dentists; nonetheless, it has been poorly addressed. An ideal system should modulate the host response, as well as enable the recruitment, proliferation and differentiation of relevant progenitor cells. Herein was proposed a photocrosslinkable hydrogel system based on hyaluronic acid (HA) and platelet lysate (PL). PL is a cocktail of growth factors (GFs) and cytokines involved in wound healing orchestration, obtained by the cryogenic processing of platelet concentrates, and was expected to provide the HA hydrogels specific biochemical cues to enhance pulp cells' recruitment, proliferation and differentiation. Stable HA hydrogels incorporating PL (HAPL) were prepared after photocrosslinking of methacrylated HA (Met-HA) previously dissolved in PL, triggered by the Ultra Violet activated photoinitiator Irgacure 2959. Both the HAPL and plain HA hydrogels were shown to be able to recruit cells from a cell monolayer of human dental pulp stem cells (hDPSCs) isolated from permanent teeth. The hDPCs were also seeded directly over the hydrogels (5 × 10 cells/hydrogel) and cultured in osteogenic conditions. Cell metabolism and DNA quantification were higher, in all time-points, for PL supplemented hydrogels (p < 0,05). Alkaline phosphatase (ALPL) activity and calcium quantification peaks were observed for the HAPL group at 21 days (p < 0,05). The gene expression for ALPL and COLIA1 was up-regulated at 21 days to HAPL, compared with HA group (p < 0,05). Within the same time point, the gene expression for RUNX2 did not differ between the groups. Overall, data demonstrated that the HA hydrogels incorporating PL increased the cellular metabolism and stimulate the mineralized matrix deposition by hDPSCs, providing clear evidence of the potential of the proposed system for the repair of damaged pulp/dentin tissue and endodontics regeneration.

Injectable and tunable hyaluronic acid hydrogels releasing chemotactic and angiogenic growth factors for endodontic regeneration

“…Human dental pulp cells (hDPCs) were isolated from human third molars under the scope of a previous study [29]. These cells were positive for mesenchymal stem cell markers such as CD73, CD90, CD105 and CD44 with over 98% of cells expressing these markers, and negative for the hematopoietic markers CD34 and CD45 (<1%) [29].…”

“…Human dental pulp cells (hDPCs) were isolated from human third molars under the scope of a previous study [29]. These cells were positive for mesenchymal stem cell markers such as CD73, CD90, CD105 and CD44 with over 98% of cells expressing these markers, and negative for the hematopoietic markers CD34 and CD45 (<1%) [29]. hDPCs were cultured in 75 cm 3 flasks with Dulbecco's Modified Eagle's Medium -low glucose (DMEM, Sigma-Aldrich, USA) and supplemented with 10% fetal bovine serum (FBS, Life Technologies, USA), and 1% antibiotic/antimycotic (Life Technologies, USA).…”

Inhibition of Hypertrophy and Improving Chondrocyte Differentiation by MMP-13 Inhibitor Small Molecule-Encapsulated in Alginate-Chondroitin Sulfate-Platelet Lysate Hydrogel

“…However, two main problems remain: high degradability rate and low mechanical properties. Combination of PL in a hydrogel can protect growth factors and biomolecules from degradation and allow their continuous release [47]. Babo PS et al incorporated PL into HA hydrogels which resulted in sustained release of growth factors and enhanced the viability of cells either encapsulated in or seeded within the hydrogels [76,77].Our results revealed that addition of PL increased the Young's modulus as well as the viscoelastic modulus (G', G") of alginate hydrogel.…”

“…The viability of hBM-MSCs encapsulated in Alg-based hydrogels was assessed. Previous studies have demonstrated the positive effect of PL upon the viability and proliferation of hBM-MSCs in combination with other hydrogels such as hyaluronic acid [47], gellan gum gels [85], coating the scaffolds [86] and even used alone as a hydrogel [50]. In addition, it has been shown that incorporation of CS into the network supports the viability and proliferation of chondrocytes for at least six weeks [87].…”

“…Platelet lysate is a cocktail of growth factors, anti-in ammatory cytokines, and clot-forming proteins that are involved in tissue repair processes [47,48]. PL is a cost-effective and autologous source of growth factors compared to recombinant growth factors [49].…”