Waldrop Tatyana Isayeva, Graham Caleb, Gard William, Ingle Kevin, Ptacek Travis, Nguyen Nguyen, Lose Bailey, Sethu Palaniappan, Lee Timmy
Department of Medicine and Division of Nephrology, University of Alabama at Birmingham, Birmingham, AL, United States.
Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, United States.
Front Bioeng Biotechnol. 2023 Feb 16;11:1101622. doi: 10.3389/fbioe.2023.1101622. eCollection 2023.
Cardiovascular events are the primary cause of death among dialysis patients. While arteriovenous fistulas (AVFs) are the access of choice for hemodialysis patients, AVF creation can lead to a volume overload (VO) state in the heart. We developed a three-dimensional (3D) cardiac tissue chip (CTC) with tunable pressure and stretch to model the acute hemodynamic changes associated with AVF creation to complement our murine AVF model of VO. In this study, we aimed to replicate the hemodynamics of murine AVF models and hypothesized that if 3D cardiac tissue constructs were subjected to "volume overload" conditions, they would display fibrosis and key gene expression changes seen in AVF mice. Mice underwent either an AVF or sham procedure and were sacrificed at 28 days. Cardiac tissue constructs composed of h9c2 rat cardiac myoblasts and normal adult human dermal fibroblasts in hydrogel were seeded into devices and exposed to 100 mg/10 mmHg pressure (0.4 s/0.6 s) at 1 Hz for 96 h. Controls were exposed to "normal" stretch and experimental group exposed to "volume overload". RT-PCR and histology were performed on the tissue constructs and mice left ventricles (LVs), and transcriptomics of mice LVs were also performed. Our tissue constructs and mice LV both demonstrated cardiac fibrosis as compared to control tissue constructs and sham-operated mice, respectively. Gene expression studies in our tissue constructs and mice LV demonstrated increased expression of genes associated with extracellular matrix production, oxidative stress, inflammation, and fibrosis in the VO conditions vs. control conditions. Our transcriptomics studies demonstrated activated upstream regulators related to fibrosis, inflammation, and oxidative stress such as collagen type 1 complex, TGFB1, CCR2, and VEGFA and inactivated regulators related to mitochondrial biogenesis in LV from mice AVF. In summary, our CTC model yields similar fibrosis-related histology and gene expression profiles as our murine AVF model. Thus, the CTC could potentially play a critical role in understanding cardiac pathobiology of VO states similar to what is present after AVF creation and may prove useful in evaluating therapies.
心血管事件是透析患者的主要死因。虽然动静脉内瘘（AVF）是血液透析患者的首选血管通路，但建立AVF会导致心脏处于容量超负荷（VO）状态。我们开发了一种具有可调压力和拉伸功能的三维（3D）心脏组织芯片（CTC），以模拟与建立AVF相关的急性血流动力学变化，作为我们VO小鼠AVF模型的补充。在本研究中，我们旨在复制小鼠AVF模型的血流动力学，并假设如果3D心脏组织构建体处于“容量超负荷”状态，它们将表现出在AVF小鼠中观察到的纤维化和关键基因表达变化。小鼠接受AVF手术或假手术，并在28天时处死。将由h9c2大鼠心肌成纤维细胞和水凝胶中的正常成人真皮成纤维细胞组成的心脏组织构建体接种到装置中，并在1Hz频率下暴露于100mg/10mmHg压力（0.4s/0.6s）下96小时。对照组暴露于“正常”拉伸，实验组暴露于“容量超负荷”。对组织构建体和小鼠左心室（LV）进行逆转录聚合酶链反应（RT-PCR）和组织学检查，并对小鼠LV进行转录组学分析。与对照组织构建体和假手术小鼠相比，我们的组织构建体和小鼠LV均表现出心脏纤维化。在我们的组织构建体和小鼠LV中的基因表达研究表明，与对照条件相比，在VO条件下与细胞外基质产生、氧化应激、炎症和纤维化相关的基因表达增加。我们的转录组学研究表明，来自小鼠AVF的LV中与纤维化、炎症和氧化应激相关的上游调节因子如1型胶原复合物、转化生长因子β1（TGFB1）、趋化因子受体2（CCR2）和血管内皮生长因子A（VEGFA）被激活，而与线粒体生物发生相关的调节因子失活。总之，我们的CTC模型产生了与我们的小鼠AVF模型相似纤维化相关的组织学和基因表达谱。因此，CTC可能在理解与建立AVF后出现的类似VO状态的心脏病理生物学中发挥关键作用，并可能在评估治疗方法方面证明是有用的。
