1 Angelo State University, Texas Tech University System, San Angelo, TX, USA.
2 Likarda, LLC, Kansas City, MO, USA.
Cell Transplant. 2018 Jul;27(7):1017-1026. doi: 10.1177/0963689718779898. Epub 2018 Jun 28.
When working with isolated islet preparations, measuring the volume of tissue is not a trivial matter. Islets come in a large range of sizes and are often contaminated with exocrine tissue. Many factors complicate the procedure, and yet knowledge of the islet volume is essential for predicting the success of an islet transplant or comparing experimental groups in the laboratory. In 1990, Ricordi presented the islet equivalency (IEQ), defined as one IEQ equaling a single spherical islet of 150 μm in diameter. The method for estimating IEQ was developed by visualizing islets in a microscope, estimating their diameter in 50 μm categories and calculating a total volume for the preparation. Shortly after its introduction, the IEQ was adopted as the standard method for islet volume measurements. It has helped to advance research in the field by providing a useful tool improving the reproducibility of islet research and eventually the success of clinical islet transplants. However, the accuracy of the IEQ method has been questioned for years and many alternatives have been proposed, but none have been able to replace the widespread use of the IEQ. This article reviews the history of the IEQ, and discusses the benefits and failings of the measurement. A thorough evaluation of alternatives for estimating islet volume is provided along with the steps needed to uniformly move to an improved method of islet volume estimation. The lessons learned from islet researchers may serve as a guide for other fields of regenerative medicine as cell clusters become a more attractive therapeutic option.
在使用分离胰岛制备物时，测量组织体积并不是一件简单的事情。胰岛的大小范围很广，而且经常与外分泌组织混合在一起。许多因素使这个过程变得复杂，但了解胰岛的体积对于预测胰岛移植的成功或在实验室中比较实验组是至关重要的。1990 年，Ricordi 提出了胰岛当量（IEQ）的概念，定义为一个 IEQ 等于一个直径为 150μm 的球形胰岛。估计 IEQ 的方法是通过在显微镜下观察胰岛，将其直径分为 50μm 类别进行估计，并计算制备物的总体积。在其介绍之后不久，IEQ 就被采纳为胰岛体积测量的标准方法。它为该领域的研究提供了一个有用的工具，提高了胰岛研究的可重复性，最终提高了临床胰岛移植的成功率。然而，IEQ 方法的准确性多年来一直受到质疑，已经提出了许多替代方法，但没有一种方法能够取代 IEQ 的广泛应用。本文回顾了 IEQ 的历史，讨论了该测量方法的优缺点。还提供了对胰岛体积估计的替代方法的全面评估，并介绍了统一采用改进的胰岛体积估计方法所需的步骤。从胰岛研究人员那里吸取的经验教训可能会为细胞簇成为更有吸引力的治疗选择的再生医学的其他领域提供指导。
