Ramrattan Navin N, Heijkants Ralf G J C, van Tienen Tony G, Schouten Arend Jan, Veth Rene P H, Buma Pieter
Orthopedic Research Laboratory, University Medical Center Nijmegen, The Netherlands.
Tissue Eng. 2005 Jul-Aug;11(7-8):1212-23. doi: 10.1089/ten.2005.11.1212.
The continuous development of new biomaterials for tissue engineering and the enhancement of tissue ingrowth into existing scaffolds, using growth factors, create the necessity for developing adequate tools to assess tissue ingrowth rates into porous biomaterials. Current histomorphometric techniques evaluating rates of tissue ingrowth tend either to measure the overall tissue content in an entire sample or to depend on the user to indicate a front of tissue ingrowth. Neither method is particularly suitable for the assessment of tissue ingrowth rates, as these methods either lack the sensitivity required or are problematic when there is a tissue ingrowth gradient rather than an obvious tissue ingrowth front. This study describes a histomorphometric method that requires little observer input, is sensitive, and renders detailed information for the assessment of tissue ingrowth rates into porous biomaterials. This is achieved by examining a number of computer-defined concentric zones, which are based on the distance of a pixel from the scaffold edge. Each zone is automatically analyzed for tissue content, eliminating the need for user definition of a tissue ingrowth front and thus reducing errors and observer dependence. Tissue ingrowth rates in two biodegradable polyurethane scaffolds (Estane and polycaprolactone-polyurethane [PCLPU]) specifically designed for tissue engineering of the knee meniscus were assessed. Samples were subcutaneously implanted in rats with follow-up until 6 months. Especially at the earlier follow-up points, PCLPU scaffolds showed significantly higher tissue ingrowth rates than Estane scaffolds, making the PCLPU scaffold a promising candidate for further studies investigating meniscus tissue engineering.
用于组织工程的新型生物材料不断发展，且利用生长因子促进组织向现有支架内生长，因此有必要开发适当工具来评估组织向多孔生物材料内的生长速率。当前用于评估组织生长速率的组织形态计量学技术，要么是测量整个样本中的总体组织含量，要么依赖用户来指明组织生长前沿。这两种方法都不太适合评估组织生长速率，因为这些方法要么缺乏所需的灵敏度，要么在存在组织生长梯度而非明显的组织生长前沿时存在问题。本研究描述了一种组织形态计量学方法，该方法几乎不需要观察者输入，灵敏度高，并能提供详细信息以评估组织向多孔生物材料内的生长速率。这是通过检查多个基于像素到支架边缘距离的计算机定义的同心区域来实现的。每个区域会自动分析组织含量，无需用户定义组织生长前沿，从而减少误差和观察者依赖性。评估了两种专门为膝关节半月板组织工程设计的可生物降解聚氨酯支架（依斯坦和聚己内酯 - 聚氨酯[PCLPU]）中的组织生长速率。将样本皮下植入大鼠体内，随访至6个月。特别是在早期随访点，PCLPU支架的组织生长速率明显高于依斯坦支架，这使得PCLPU支架成为进一步研究半月板组织工程的有希望的候选材料。
