BIOMATEN, Middle East Technical University, Center of Excellence in Biomaterials and Tissue Engineering, Ankara, Turkey.
SPARTHA Medical, 14B Rue de la Canardiere, Strasbourg Cedex 67100, France; INSERM Unité 1121 Biomaterials and Bioengineering, CRBS, 1 Rue Eugène Boeckel, Strasbourg Cedex 67000, France.
Biomater Adv. 2022 Jul;138:212872. doi: 10.1016/j.bioadv.2022.212872. Epub 2022 May 18.
The extensive innate immune response to implanted biomaterials contributes significantly to their sub-par performance and failure. Granuloma formation is one of such reactions which results in multi-cell type clusters in line with the immune reaction to implanted materials. However, currently no in vitro model of granuloma formation exists that takes into account the arrival of multiple cell types (immune cells and connective tissue cells) to the implant insertion site. In this study, we developed a two-step model based on stimulated macrophage seeding followed by fibroblast introduction after a physiologically relevant time period for mimicking initial steps of immune reaction to biomaterials and inducing granuloma like behavior. Both LPS and TNF-α induction resulted in granuloma like formations which persisted longer than the control conditions. Introduction of human fibroblasts resulted in the colonization of the surfaces where the cell numbers and the collagen secretion were dependent on the microenvironment. In order to demonstrate the capacity of our model system to monitor the reaction to a given coating, a validated antimicrobial coating (Polyarginine (PAR)/Hyaluronic acid (HA)) was used as a testing bed. The coating prevented the adhesion of macrophages while allowing the adhesion of the fibroblast at the time of their arrival. Similar to its antimicrobial activity, macrophage metabolic activity and M2 differentiation in the presence of PAR was dependent to its chain length. The incorporation of fibroblasts resulted in decreased TNF-α and increased IL-1RA secretion especially in stimulation conditions. The pro- and anti-inflammatory cytokine secretions were low for PAR/HA coatings in line with the decreased number of macrophage presence. In the presence of complex PBMC population, the coating resulted in slightly less cellular attachment, without any significant cytokine secretion; the absence of inflammatory reaction was also demonstrated in vivo in a mouse model. The described in vitro granuloma testing system can control the macrophage reaction as a function of stimulation. It can also be used for testing new biomaterials for the potential innate immune responses and also for validation of implant coatings beyond their primary function from the immune response point of view.
植入生物材料引起的广泛固有免疫反应是导致其性能不佳和失效的主要原因。肉芽肿形成是其中一种反应，导致多细胞类型簇与植入材料的免疫反应一致。然而，目前尚无考虑到多种细胞类型（免疫细胞和结缔组织细胞）到达植入物插入部位的肉芽肿形成的体外模型。在这项研究中，我们开发了一种两步模型，基于刺激巨噬细胞接种，然后在生理相关时间后引入成纤维细胞，以模拟对生物材料的免疫反应的初始步骤并诱导类肉芽肿行为。LPS 和 TNF-α 诱导均导致类肉芽肿形成，其持续时间长于对照条件。引入人成纤维细胞导致细胞数量和胶原蛋白分泌依赖于微环境的表面定植。为了证明我们的模型系统监测对给定涂层的反应的能力，使用经过验证的抗菌涂层（聚精氨酸（PAR）/透明质酸（HA））作为测试床。该涂层阻止了巨噬细胞的黏附，同时允许成纤维细胞在其到达时黏附。类似于其抗菌活性，PAR 存在时巨噬细胞代谢活性和 M2 分化取决于其链长。成纤维细胞的掺入导致 TNF-α减少和 IL-1RA 分泌增加，特别是在刺激条件下。PAR/HA 涂层的促炎和抗炎细胞因子分泌较低，与巨噬细胞存在数量减少一致。在复杂的 PBMC 群体存在的情况下，涂层导致细胞附着略有减少，没有任何明显的细胞因子分泌; 在小鼠模型中也体内证明了炎症反应的缺失。所描述的体外肉芽肿测试系统可以根据刺激来控制巨噬细胞反应。它还可用于测试新的生物材料，以了解其潜在的固有免疫反应，并且还可以从免疫反应的角度验证植入物涂层的功能。
