Azzarello Joseph, Ihnat Michael A, Kropp Bradley P, Warnke Linda A, Lin Hsueh-Kung
Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA.
Biomed Mater. 2007 Jun;2(2):55-61. doi: 10.1088/1748-6041/2/2/001. Epub 2007 Mar 7.
The angiogenic potential of a biomaterial is a critical factor for successful graft intake in tissue engineering. We developed a modified, rapid and reproducible chicken embryo chorioallantoic membrane (CAM) assay to evaluate the ability of biomaterials in inducing blood vessel density. Five biomaterials including one-layer porcine small intestinal submucosa (SIS), two-layer SIS, four-layer vacuum pressed (VP) SIS, polyglycolic acid (PGA) and PGA modified with poly(lactic-co-glycolic acid) (PLGA) were analyzed. A circular section (1.2 mm diameter) of each biomaterial was placed near a group of blood vessels in the CAM. Blood vessels around the biomaterials were captured with black and white images at 96 h post implantation; and the images were subjected to densitometry evaluation. One-layer SIS induced a significant increase in blood vessel density as compared to the cellulose nitrate negative control, and had the greatest increase in blood vessel density as compared to four-layer VP SIS, PGA, or PLGA modified PGA. Although two-layer SIS has enhanced physical structure for surgical manipulation, its induction in blood vessel density was significantly lower than the one-layer SIS. Stripping the SIS proteins or incubating one-layer SIS with neutralizing antibodies against basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) resulted in decreased angiogenesis. Consistent with results obtained from bladder augmentation animal models, these results confirmed that angiogenic growth factors were present in SIS and affected the angiogenic potential of biomaterials. These data also demonstrated that the CAM assay can be used to ascertain methodically the angiogenic potential of biomaterials.
生物材料的血管生成潜力是组织工程中移植物成功植入的关键因素。我们开发了一种改良的、快速且可重复的鸡胚绒毛尿囊膜（CAM）试验，以评估生物材料诱导血管密度的能力。分析了五种生物材料，包括单层猪小肠黏膜下层（SIS）、双层SIS、四层真空压制（VP）SIS、聚乙醇酸（PGA）以及用聚（乳酸-共-乙醇酸）（PLGA）修饰的PGA。将每种生物材料的圆形切片（直径1.2毫米）放置在CAM中一组血管附近。在植入后96小时用黑白图像捕获生物材料周围的血管；并对图像进行光密度测定评估。与硝酸纤维素阴性对照相比，单层SIS诱导血管密度显著增加，并且与四层VP SIS、PGA或PLGA修饰的PGA相比，其血管密度增加最大。尽管双层SIS具有增强的物理结构便于手术操作，但其诱导的血管密度显著低于单层SIS。去除SIS蛋白或用抗碱性成纤维细胞生长因子（bFGF）或血管内皮生长因子（VEGF）的中和抗体孵育单层SIS会导致血管生成减少。与膀胱扩大动物模型获得的结果一致，这些结果证实血管生成生长因子存在于SIS中并影响生物材料的血管生成潜力。这些数据还表明，CAM试验可用于系统地确定生物材料的血管生成潜力。
