Injectable soft-tissue augmentation by tissue engineering and regenerative medicine with human mesenchymal stromal cells, platelet-rich plasma and hyaluronic acid scaffolds.

Abstract

The aim of this study was to evaluate the possibility of soft-tissue augmentation adopting tissue engineering and regenerative medicine (TERM) technology for a longer duration of injected implants. TERM is the combination and re-organization of three types of injection materials to regenerate organs and tissues: (i) living cells, including cultured human mesenchymal stromal cells (hMSCs) and human fibroblasts (hFibro); (ii) scaffolds of hyaluronic acid (HA); and (iii) growth factors of platelet-rich plasma (PRP). The experimental combinations were as follows: HA, HA/hFibro, HA/hMSCs, HA/PRP, HA/PRP/hFibro and HA/PRP/hMSCs. These were injected intradermally into immunodeficient rats and evaluated by histologic analysis, percentage of original volume and maintenance volume. The percentage of original volume values at 14 days were 0.02 +/- 0.01% (HA), 0.20 +/- 0.03% (HA/hFibro), 0.50 +/- 0.02% (HA/hMSCs), 11.66 +/- 1.81% (HA/PRP), 24.36 +/- 8.97% (HA/PRP/hFibro) and 28.04 +/- 4.11% (HA/PRP/hMSCs), respectively. There were significant differences between groups with and without PRP. Regarding maintenance volume values, HA/PRP, HA/PRP/hFibro and HA/PRP/hMSCs from 7 to 14 days were also higher, at 46.25 +/- 1.21%, 78.39 +/- 2.90% and 88.81 +/- 5.97%, respectively. HA/PRP/hMSCs groups maintained the shape and dimensions of the injected implant, indicating that the injected cells produced type I collagen. The findings suggest that a soft tissue-engineered procedure with MSCs may be useful for longer lasting soft-tissue augmentation.