Gishto Arsela, Farrell Kurt, Kothapalli Chandrasekhar R
Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, Ohio, 44115.
J Biomed Mater Res A. 2015 Feb;103(2):693-708. doi: 10.1002/jbm.a.35217. Epub 2014 May 19.
A major onset of heart failure is myocardial infarction, which causes the myocardium to lose cardiomyocytes and transform into a scar tissue. Since mammalian infarcted cardiac tissue has a limited ability to regenerate, alternative strategies including implantation of tissue-engineered scaffolds at the site of damaged myocardium have been explored. The goal is to enable in situ cardiac reconstruction at the injured myocardium site, replace the lost cardiomyocytes, deliver the required biomolecules, and remodel the extracellular matrix (ECM). ECM synthesis and deposition by cardiomyocytes within such scaffolds remains categorically unexplored. Here, we investigated the survival, ECM synthesis and deposition, and matrix metalloproteinases (MMPs) release by cardiomyocytes within three-dimensional (3D) substrates. Rat cardiomyocytes were cultured for three weeks within two structurally different substrates: 3D collagen hydrogels or polycaprolactone (PCL) nanofibrous scaffolds. The concentration and composition of the hydrogels was varied, while PCL nanofibers were surface-modified with various ECM proteins. Results showed that myocyte attachment and survival was higher within collagen hydrogels, while myocyte alignment and beating was noted only within PCL scaffolds. Total protein synthesis by myocytes within PCL scaffolds was significantly higher compared to that within collagen hydrogels, although more protein was deposited as matrix within hydrogels. Significant ECM synthesis and matrix deposition, TIMP-1, and MMP release were noted within modified collagen hydrogels and PCL nanofiber scaffolds. These results were qualitatively confirmed by imaging techniques. Results attest to the prominent role of scaffold composition and architecture in influencing cardiomyocyte phenotype, matrix synthesis and cytokines release, with significant applications in cardiac tissue remodeling strategies.
心力衰竭的主要发病原因是心肌梗死，它会导致心肌失去心肌细胞并转化为瘢痕组织。由于哺乳动物梗死的心脏组织再生能力有限，人们探索了包括在受损心肌部位植入组织工程支架在内的替代策略。目标是在受损心肌部位实现原位心脏重建，替代丢失的心肌细胞，递送所需的生物分子，并重塑细胞外基质（ECM）。在此类支架内心肌细胞对ECM的合成和沉积情况仍完全未被探索。在这里，我们研究了心肌细胞在三维（3D）基质中的存活、ECM合成与沉积以及基质金属蛋白酶（MMPs）的释放情况。大鼠心肌细胞在两种结构不同的基质中培养三周：3D胶原水凝胶或聚己内酯（PCL）纳米纤维支架。改变水凝胶的浓度和组成，同时用各种ECM蛋白对PCL纳米纤维进行表面修饰。结果表明，心肌细胞在胶原水凝胶中的附着和存活率更高，而仅在PCL支架中观察到心肌细胞排列和搏动。与胶原水凝胶相比，PCL支架中心肌细胞的总蛋白合成显著更高，尽管更多的蛋白作为基质沉积在水凝胶中。在修饰的胶原水凝胶和PCL纳米纤维支架中观察到显著的ECM合成、基质沉积、TIMP - 1和MMP释放。这些结果通过成像技术得到定性证实。结果证明了支架组成和结构在影响心肌细胞表型、基质合成和细胞因子释放方面的重要作用，在心脏组织重塑策略中有重要应用。
