Naturally derived myocardial matrix as an injectable scaffold for cardiac tissue engineering. Biomaterials

Department of Bioengineering, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0412, USA.
Biomaterials (Impact Factor: 8.56). 08/2009; 30(29):5409-16. DOI: 10.1016/j.biomaterials.2009.06.045
Source: PubMed


Myocardial tissue lacks the ability to significantly regenerate itself following a myocardial infarction, thus tissue engineering strategies are required for repair. Several injectable materials have been examined for cardiac tissue engineering; however, none have been designed specifically to mimic the myocardium. The goal of this study was to investigate the in vitro properties and in vivo potential of an injectable myocardial matrix designed to mimic the natural myocardial extracellular environment. Porcine myocardial tissue was decellularized and processed to form a myocardial matrix with the ability to gel in vitro at 37 degrees C and in vivo upon injection into rat myocardium. The resulting myocardial matrix maintained a complex composition, including glycosaminoglycan content, and was able to self-assemble to form a nanofibrous structure. Endothelial cells and smooth muscle cells were shown to migrate towards the myocardial matrix both in vitro and in vivo, with a significant increase in arteriole formation at 11 days post-injection. The matrix was also successfully pushed through a clinically used catheter, demonstrating its potential for minimally invasive therapy. Thus, we have demonstrated the initial feasibility and potential of a naturally derived myocardial matrix as an injectable scaffold for cardiac tissue engineering.

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Available from: Karen L Christman, Dec 31, 2013
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    • "Only patient age was provided for the six patients (p1-6) and is as follows: p1-43, p2-52, p3-63, p4-69, p5-63, and p6-34. The methods for decellularizing human myocardial tissue have been previously reported [4], and were based on methods developed for decellularizing porcine myocardium [6]. In brief, human cardiac tissue was collected from 6 different patients. "
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    ABSTRACT: The purpose of this study was to characterize and quantitatively analyze human cardiac extracellular matrix (ECM) isolated from six different cadaveric donor hearts. ECM was isolated by decellularization of six human cadaveric donor hearts and characterized by quantifying sulfated glycosaminoglycan content (sGAG) and via polyacrylamide gel electrophoresis (PAGE). The protein content was then quantified using ECM-targeted Quantitative conCATamers (QconCAT) by Liquid Chromatography - Selected Reaction Monitoring (LC-SRM) analysis using 83 stable isotope labeled (SIL) peptides representing 48 different proteins. Non-targeted global analysis was also implemented using liquid chromatography tandem mass spectrometry (LC-MS/MS). The sGAG content, PAGE, and QconCAT proteomics analysis showed significant variation between each of the six patient samples. The quantitative proteomics indicated that the majority of the protein content was composed of various fibrillar collagen components. Also, quantification of difficult to remove cellular proteins represented less than 1% of total protein content, which is very low for a decellularized biomaterial. Global proteomics identified over 200 distinct proteins present in the human cardiac ECM. In conclusion, quantification and characterization of human myocardial ECM showed significant patient-to-patient variability between the six investigated patients. This is an important outcome for the development of allogeneic derived biomaterials and for increasing our understanding of human myocardial ECM composition. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
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    • "Left ventricular tissue was separated from the rest of the heart and utilized for matrix collection. The left ventricular tissue was decellularized and prepared as previously described [43] [44]. "
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    ABSTRACT: Cardiac malformations and disease are the leading causes of death in the United States in live-born infants and adults, respectively. In both of these cases, a decrease in the number of functional cardiomyocytes often results in improper growth of heart tissue, wound healing complications, and poor tissue repair. The field of cardiac tissue engineering seeks to address these concerns by developing cardiac patches created from a variety of biomaterial scaffolds to be used in surgical repair of the heart. These scaffolds should be fully degradable biomaterial systems with tunable properties such that the materials can be altered to meet the needs of both in vitro culture (e.g. disease modeling) and in vivo application (e.g. cardiac patch). Current platforms do not utilize both structural anisotropy and proper cell-matrix contacts to promote functional cardiac phenotypes and thus there is still a need for critically sized scaffolds that mimic both the structural and adhesive properties of native tissue. To address this need, we have developed a silk-based scaffold platform containing cardiac tissue-derived extracellular matrix (cECM). These silk-cECM composite scaffolds have tunable architectures, degradation rates, and mechanical properties. Subcutaneous implantation in rats demonstrated that addition of the cECM to aligned silk scaffold led to 99% endogenous cell infiltration and promoted vascularization of a critically sized scaffold (10 × 5 × 2.5 mm) after 4 weeks in vivo. In vitro, silk-cECM scaffolds maintained the HL-1 atrial cardiomyocytes and human embryonic stem cell-derived cardiomyocytes and promoted a more functional phenotype in both cell types. This class of hybrid silk-cECM anisotropic scaffolds offers new opportunities for developing more physiologically relevant tissues for cardiac repair and disease modeling.
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    • "Preparation of ECM-only hydrogels ECM hydrogels were prepared using various concentrations of TG (0, 1.2, 12 and 120 lg ml À1 ). Decellularized ECM solution was neutralized and diluted to 6 mg ml À1 [16] before adding TG, vortexed briefly and then pipetted into 15 Â 15 Â 5 mm Tissue-Tek cryomolds (Ted Pella, Inc.). Samples were incubated at 37 °C for $30 min. "
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    ABSTRACT: Solubilized cardiac extracellular matrix (ECM) is being developed as an injectable therapeutic that offers promise for promoting cardiac repair. However, the ECM alone forms a hydrogel that is very soft compared to the native myocardium. As both the stiffness and composition of the ECM are important in regulating cell behavior and can have complex synergistic effects, we sought to develop an ECM-based scaffold with tunable biochemical and mechanical properties. We used solubilized rat cardiac ECM from two developmental stages (neonatal, adult) combined with fibrin hydrogels that were crosslinked with transglutaminase. We show that ECM was retained within the gels and Young’s modulus could be tuned to span the range of the developing and mature heart. C-kit+ cardiovascular progenitor cells from pediatric patients with congenital heart defects were seeded into the hybrid gels. Both the elastic modulus and composition of the scaffolds impacted the expression of endothelial and smooth muscle cell genes. Furthermore, we demonstrate that the hybrid gels are injectable, and thus have potential for minimally invasive therapies. ECM-fibrin hybrid scaffolds offer new opportunities for exploiting the effects of both composition and mechanical properties in directing cell behavior for tissue engineering.
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