Vascular endothelial growth factor released by vessel extracellular matrix for ureteral defect repairing: Enhanced vascularization?

Wengong JIANG; Zhankui ZHAO; Sixing YANG; Kailiang ZHAO; Minjie ZHANG; Xiangxiang YU; Linglong WANG

ABSTRACT

BACKGROUND:

Vessel extracellular matrix (VECM) is a natural scaffold material obtained from vascular tissues, which can stimulate angiogenesis and accelerate vascularization of tissue-engineered graft, however, the mechanism is poorly understood.

OBJECTIVE:

To explore the vascularization effects of release of vascular endothelial growth factor (VEGF) from VECM in ureteral reconstitution.DESIGN, TIME AND

SETTING:

An in vitro cytology observation. The experiment was performed at the Biomedical Engineering Laboratory of First Clinical Medical Science College, Wuhan University, between April and August in 2009.MATERIALS Abdominal aorta was obtained from 5 rabbits to prepare VECM.

METHODS:

The VEGF released from VECM in vitro was evaluated by ELISA, the effects of cell proliferation by the released VEGF was detected by MTT colorimetric assay. The defected ureters of rabbits were repaired by homologous VECM in vivo.Then the recovery of the defected ureters and the situation of vasculogenesis were detected at different time point.MAIN OUTCOME

MEASURES:

The detection of VEGF contents in VECM; and the effects of VECM on vascular endothelial cell proliferation and ureteral reconstitution.

RESULTS:

In vitro experiment presented that the peak amplitude concentration of VEGF released from VECM in PBS solution was (124.10±1.42) ng/L, which showed proliferative effect on vascular endothelial cells. In vivo, there were some blood vessels on the VECM at 2 weeks after implantation. Epithelial coverage was evident in the lumen of the marginal part of the VECM grafts and the smooth muscle extended from the transition zone. After 8 weeks, the quantity of the blood vessel was increased and the caliber of the blood vessels became wide. There was thickness epithelial lamina in the graft, and the muscle fibers had an organized spatial alignment, forming variably sized bundles. After 16 weeks, there were no significant differences between the regenerative tissue and the normal tissue in morphology.

CONCLUSION:

The homologous VECM can release VEGF when implanted as tissue engineer biomaterial and might be an ideal replacement biomaterial for ureteral reconstitution.