Rizzoli Orthopedic Institute, Laboratory of Preclinical and Surgical Studies, Bologna, Italy.
Department RIT Rizzoli, Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, Rizzoli Orthopedic Institute, Bologna, Italy.
J Cell Physiol. 2018 Jan;233(1):291-301. doi: 10.1002/jcp.25875. Epub 2017 May 3.
The dynamic metabolism and the numerous roles of bone tissue necessitate a suitable in vitro model to represent them. In order to investigate the interaction among the several cell types composing bone microenvironment, we studied a tri-culture model including human osteoblasts (OBs), osteoclasts (OCs), and endothelial cells (HUVEC). While OBs are essential for bone deposition and OCs for bone resorption, the vasculature is necessary to provide growth factors, nutrients, and oxygen in the mature tissue. The results of this study showed a strong mutual influence between OBs, OCs, and HUVEC in term of proliferation, viability, and activity (release of ALP, Coll I, OPG, RANKL, VEGF, CTSK, TGFβ, and IL-6). The behavior of the single cultures demonstrated to be different compared to the bi- or tri-cultures and depending on the cell types involved: the coexistence of OBs and OCs stimulated the synthetic activity of both cell types, while the presence of HUVEC induced a stimulating role for OBs but mainly an inhibitory effect for OC. In addition, evidence of the effects of OBs and OCs on HUVEC is highlighted by their morphology: regular and able to "sketch" little vessels in presence of OBs, more disorganized and heterogeneous in presence of OCs. Taken together, these observations well characterize an advanced cellular model to be used as starting point for mimicking bone microenvironment in vivo, thus reducing the use of animals in the preclinical phase and offering a more reliable tool to test new and innovative biomaterials.
骨骼组织具有活跃的新陈代谢和多种功能，因此需要合适的体外模型来对其进行模拟。为了研究构成骨微环境的多种细胞类型之间的相互作用，我们研究了一种包含人成骨细胞（OBs）、破骨细胞（OCs）和内皮细胞（HUVEC）的三细胞共培养模型。OBs 对于骨沉积至关重要，OCs 则负责骨吸收，而血管则为成熟组织提供生长因子、营养物质和氧气。本研究结果表明，OBs、OCs 和 HUVEC 之间在增殖、活力和活性（碱性磷酸酶、Coll I、OPG、RANKL、VEGF、CTSK、TGFβ和 IL-6 的释放）方面存在强烈的相互影响。与双细胞或三细胞培养相比，单细胞培养的行为有所不同，且取决于所涉及的细胞类型：OBs 和 OCs 的共存刺激了两种细胞类型的合成活性，而 HUVEC 的存在则对 OBs 产生了刺激作用，但主要对 OC 产生了抑制作用。此外，OBs 和 OCs 对 HUVEC 的影响还通过其形态得到了证明：在 OBs 存在的情况下，HUVEC 的形态规则且能够“勾勒”出小血管；而在 OCs 存在的情况下，HUVEC 的形态则更加紊乱和不均匀。综上所述，这些观察结果很好地描述了一种先进的细胞模型，可作为模拟体内骨微环境的起点，从而减少在临床前阶段使用动物，并提供更可靠的工具来测试新的和创新的生物材料。
