Preliminary study on the effect of vascular endothelial growth factor-loaded self-assembled peptide hydrogel on angiogenesis and vascularization of human umbilical vein endothelial cells

Abstract

Objective: To investigate the effect of RATEA16 scaffold on the proliferation of human umbilical vein endothelial cells (HUVEC) and the effect of new self-assembling peptide hydrogel (RATEA16) scaffold with vascular endothelial growth factor (VEGF) on promoting angiogenesis. Methods: RATEA16 hydrogel was prepared, then the injectability, microstructure, degradation, biocompatibility of RATEA16 hydrogel were determined. HUVEC were cultured with RATEA16 scaffold to detect cell morphology and proliferation. HUVEC were cultured on RATEA16 scaffold with VEGF for 24 h. The expression of VEGF-A, von Willebrand factor (vWF), matrix metalloproteinase-9 (MMP-9) and platelet endothelial cell adhesion molecule-1 (PECAM-1) were detected by using real-time PCR to evaluate the effects of the scaffold with VEGF system on HUVEC differentiation. Results: The sol-gel transition was completed under neutral condition (pH=7.4) adjusted by Tris-HCl solution. The hydrogel could be easily injected from a syringe. It presented a porous and interconnected internal structure and the porosity of the scaffold was (67.3±9.4)%. After 4 week degradation in vitro, the residual weight was still (82.354±0.006)%, which exhibited slow degradation. HUVEC grew well after being cultured in leach liquor of RATEA16 hydrogel for 24 h, and there was no significant difference in HUVEC cell viability compared with that of the control group (P>0.05). HUVEC encapsulated in RATEA16 hydrogel appeared round in shape and exhibited effectively continuous proliferation. When HUVEC were cultured on RATEA16 hydrogel with VEGF for 24 h, the formation of vascular-like structures was observed. The expression of VEGF-A and MMP-9 was 1.5-2.0 times that of control group, and vWF was 10 times and PECAM-1 was 55 times compared with that of the control group (P<0.05). Conclusions: The RATEA16 hydrogel used in this study could be prepared by simply adjusting pH to neutral. This hydrogel exhibited good biodegradability, slow degradation and injectability. HUVEC might attach and spread in RATEA16 scaffold. The RATEA16 scaffold with VEGF could promote angiogenic differentiation of HUVEC. The novel scaffold is expected to achieve the critical vascularization process in bone tissue regeneration.