The Avram and Stella Goldstein-Goren Dept. of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel.
Biotechnol Prog. 2012 Nov-Dec;28(6):1551-9. doi: 10.1002/btpr.1633. Epub 2012 Oct 18.
Cardiac tissue engineering presents a challenge due to the complexity of the muscle tissue and the need for multiple signals to induce tissue regeneration in vitro. We investigated the effects of compression (1 Hz, 15% strain) combined with fluid shear stress (10(-2) -10(-1) dynes/cm(2) ) provided by medium perfusion on the outcome of cardiac tissue engineering. Neonatal rat cardiac cells were seeded in Arginine-Glycine-Aspartate (RGD)-attached alginate scaffolds, and the constructs were cultivated in a compression bioreactor. A daily, short-term (30 min) compression (i.e., "intermittent compression") for 4 days induced the formation of cardiac tissue with typical striation, while in the continuously compressed constructs (i.e., "continuous compression"), the cells remained spherical. By Western blot, on day 4 the expression of the gap junction protein connexin 43 was significantly greater in the "intermittent compression" constructs and the cardiomyocyte markers (α-actinin and N-cadherin) showed a trend of better preservation compared to the noncompressed constructs. This regime of compression had no effect on the proliferation of nonmyocyte cells, which maintained low expression level of proliferating cell nuclear antigen. Elevated secretion levels of basic fibroblast growth factor and transforming growth factor-β in the daily, intermittently compressed constructs likely attributed to tissue formation. Our study thus establishes the formation of an improved cardiac tissue in vitro, when induced by combined mechanical signals of compression and fluid shear stress provided by perfusion.
心脏组织工程面临挑战，因为肌肉组织复杂，需要多种信号来诱导体外组织再生。我们研究了压缩（1 Hz，15%应变）与由介质灌注提供的流体切应力（10(-2) -10(-1) 达因/平方厘米）相结合对心脏组织工程结果的影响。将新生大鼠心脏细胞接种到附着 Arg-Gly-Asp（RGD）的藻酸盐支架中，并在压缩生物反应器中培养构建体。每天进行短期（30 分钟）压缩（即“间歇压缩”）4 天可诱导具有典型条纹的心脏组织形成，而在连续压缩的构建体（即“连续压缩”）中，细胞仍呈球形。通过 Western blot，在第 4 天，“间歇压缩”构建体中连接蛋白 43 的表达显著增加，与未压缩的构建体相比，心肌标志物（α-肌动蛋白和 N-钙粘蛋白）的表达趋势更好。这种压缩方案对非心肌细胞的增殖没有影响，非心肌细胞的增殖细胞核抗原表达水平保持较低。在每日间歇压缩的构建体中，碱性成纤维细胞生长因子和转化生长因子-β的分泌水平升高，可能是组织形成的原因。因此，我们的研究确立了在灌注提供的压缩和流体切应力联合机械信号诱导下，体外形成更好的心脏组织。
