Sequential Application of Steady and Pulsatile Medium Perfusion Enhanced the Formation of Engineered Bone
Sequential Application of Steady and Pulsatile Medium Perfusion Enhanced the Formation of Engineered Bone
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DOI：
10.1089/ten.tea.2011.0701
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发表时间：
2013-05-01
影响因子：
4.1
通讯作者：
Vunjak-Novakovic, Gordana
中科院分区：
文献类型：
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作者：
Correia, Cristina;Bhumiratana, Sarindr;Vunjak-Novakovic, Gordana
在天然骨中，细胞经历由与习惯负荷相关的脉动间质流引起的波动剪切力。我们假设，通过将这种生理刺激复制到使用介质灌注的生物反应器在多孔支架中培养的成骨细胞上，可以增强工程骨的形成。为了检验这一假设，我们研究了流体流动方式对在多孔三维丝素蛋白支架上培养的人脂肪干细胞（hASC）体外骨样组织发育的影响。为此，我们改变了 5 周内施加的培养基的稳定流 (SF) 和脉动流 (PF) 的连续相对持续时间，并评估了它们对骨形成早期阶段的影响。多孔丝素蛋白支架（孔径为 400-600 mm）接种 hASC（30 x 10(6) 细胞/mL），并在四种不同的流体流动模式下在成骨培养基中培养：（1）PF 5 周； （2）SF 1周，PF 4周； (3) SF 2周，PF 3周； (4) SF 5周。 PF 每隔 12 小时应用一次，间隙速度以 0.5 Hz 频率在 400 至 1200 μm/s 之间波动 2 小时，然后进行 10 小时 SF。在所有组中，SF 以 400 μm/s 的速度施加。 2 周 SF 和 3 周 PF 的序列获得了最佳成骨结果，基因表达（包括 PGE2 机械转导标记）、构建成分、组织形态和生物力学特性证明了这一点。因此，我们提出 hASC 中的成骨和随后的早期骨发育涉及一种机制，该机制检测并响应流体动力剪切力的水平和持续时间。
In native bone, cells experience fluctuating shear forces that are induced by pulsatile interstitial flow associated with habitual loading. We hypothesized that the formation of engineered bone can be augmented by replicating such physiologic stimuli to osteogenic cells cultured in porous scaffolds using bioreactors with medium perfusion. To test this hypothesis, we investigated the effect of fluid flow regime on in vitro bone-like tissue development by human adipose stem cells (hASC) cultivated on porous three-dimensional silk fibroin scaffolds. To this end, we varied the sequential relative durations of steady flow (SF) and pulsatile flow (PF) of culture medium applied over a period of 5 weeks, and evaluated their effect on early stages of bone formation. Porous silk fibroin scaffolds (400-600 mm pore size) were seeded with hASC (30 x 10(6) cells/mL) and cultured in osteogenic medium under four distinct fluid flow regimes: (1) PF for 5 weeks; (2) SF for 1 week, PF for 4 weeks; (3) SF for 2 weeks, PF for 3 weeks; (4) SF for 5 weeks. The PF was applied in 12 h intervals, with the interstitial velocity fluctuating between 400 and 1200 mu m/s at a 0.5 Hz frequency for 2 h, followed by 10 h of SF. In all groups, SF was applied at 400 mu m/s. The best osteogenic outcomes were achieved for the sequence of 2 weeks of SF and 3 weeks of PF, as evidenced by gene expression (including the PGE2 mechanotransduction marker), construct compositions, histomorphologies, and biomechanical properties. We thus propose that osteogenesis in hASC and the subsequent early stage bone development involve a mechanism, which detects and responds to the level and duration of hydrodynamic shear forces.