Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.
Instituto de Engenharia Biomédica (INEB), Universidade do Porto, Porto, Portugal.
Methods Mol Biol. 2022;2492:267-276. doi: 10.1007/978-1-0716-2289-6_15.
The blood-brain barrier (BBB) is the most selective protecting layer of the central nervous system (CNS) with unique neurovascular features. The BBB is known to undergo a process of molecular alterations during disease state, such as in the case of glioma. This results in a non-uniform permeability along the BBB layer, which retains intact regions but develops focal sites of higher leakiness, especially in the surrounds of the tumor core. Although essential to guarantee brain homeostasis, the BBB has been the Achilles heel of drug delivery to the brain since the early times of the first classification as "barrier," more than a century ago. Due to the presence of the BBB, the transport of drug molecules from the bloodstream to the brain parenchyma is highly restricted, and, therefore, clinically relevant therapeutic concentrations cannot be achieved. Research efforts have focused on the development of novel tools to ameliorate drug permeability across the BBB, including drug formulation into non-invasive delivery systems with brain targeting properties and techniques that allow a temporary disruption of the BBB. To strengthen the advancement of potential drug candidates, in vitro models that recapitulate the main in vivo features of BBB are required to perform a preliminary screening of permeability, both in health and disease conditions. Herein, a protocol to assemble a BBB in vitro model to screen drug permeability in a glioma disease state is detailed. The model consists of a BBB and glioma cell co-culture and aims at exploiting the effect of the interplay between the cell constituents on the permeability of drug molecules. Although simple and straightforward, the herein in vitro model presents a high reproducibility, cost-effectiveness, and a favorable time-benefit balance.
血脑屏障（BBB）是中枢神经系统（CNS）最具选择性的保护层，具有独特的神经血管特征。已知 BBB 在疾病状态下会经历分子改变的过程，例如在脑胶质瘤的情况下。这导致 BBB 层的通透性不均匀，保留完整的区域，但会形成更高通透性的局灶性部位，特别是在肿瘤核心周围。尽管 BBB 对于保证脑内平衡至关重要，但自从一个多世纪前首次被分类为“屏障”以来，它一直是药物向大脑输送的阿喀琉斯之踵。由于 BBB 的存在，药物分子从血液到脑实质的转运受到高度限制，因此无法达到临床相关的治疗浓度。研究工作集中在开发新工具来改善药物穿过 BBB 的通透性，包括将药物制剂制成具有脑靶向特性的非侵入性递送系统，以及允许暂时破坏 BBB 的技术。为了加强潜在药物候选物的进展，需要体外模型来模拟 BBB 的主要体内特征，以在健康和疾病状态下对通透性进行初步筛选。本文详细介绍了一种用于筛选脑胶质瘤疾病状态下药物通透性的体外 BBB 模型的组装方案。该模型由 BBB 和脑胶质瘤细胞共培养组成，旨在利用细胞成分之间相互作用对药物分子通透性的影响。虽然简单直接，但本文中的体外模型具有较高的重现性、成本效益和良好的时间效益平衡。
