Other Publications (7)
- Biomedical Materials (Bristol, England)
- Proceedings of the IEEE ... Annual Northeast Bioengineering Conference. IEEE Northeast Bioengineering Conference
- Cellular and Molecular Bioengineering
- Tissue Engineering. Part C, Methods
- Stem Cells International
- Acta Biomaterialia
- Journal of Molecular and Cellular Cardiology
Articles by Kareen L.K. Coulombe in JoVE
Custom Engineered Tissue Culture Molds from Laser-etched Masters Nicholas J. Kaiser1, Fabiola Munarin1, Kareen L.K. Coulombe1 1Center for Biomedical Engineering,, Brown University Herein we present a rapid, facile, and low-cost method for fabricating custom polydimethylsiloxane molds that can be used for producing hydrogel-based engineered tissues with complex geometries. We additionally describe results from mechanical and histological assessments conducted on engineered cardiac tissues produced using this technique.
Other articles by Kareen L.K. Coulombe on PubMed
Physiologically Inspired Cardiac Scaffolds for Tailored in Vivo Function and Heart Regeneration Biomedical Materials (Bristol, England). | Pubmed ID: 25970645 Tissue engineering is well suited for the treatment of cardiac disease due to the limited regenerative capacity of native cardiac tissue and the loss of function associated with endemic cardiac pathologies, such as myocardial infarction and congenital heart defects. However, the physiological complexity of the myocardium imposes extensive requirements on tissue therapies intended for these applications. In recent years, the field of cardiac tissue engineering has been characterized by great innovation and diversity in the fabrication of engineered tissue scaffolds for cardiac repair and regeneration to address these problems. From early approaches that attempted only to deliver cardiac cells in a hydrogel vessel, significant progress has been made in understanding the role of each major component of cardiac living tissue constructs (namely cells, scaffolds, and signaling mechanisms) as they relate to mechanical, biological, and electrical in vivo performance. This improved insight, accompanied by modern material science techniques, allows for the informed development of complex scaffold materials that are optimally designed for cardiac applications. This review provides a background on cardiac physiology as it relates to critical cardiac scaffold characteristics, the degree to which common cardiac scaffold materials fulfill these criteria, and finally an overview of recent in vivo studies that have employed this type of approach.
Vascular Perfusion of Implanted Human Engineered Cardiac Tissue Proceedings of the IEEE ... Annual Northeast Bioengineering Conference. IEEE Northeast Bioengineering Conference. | Pubmed ID: 26807015 Regeneration of muscle tissue in the heart after a myocardial infarction requires delivering human cardiomyocytes that will survive and integrate with the host myocardium. Of primary importance is the development of a vascular bed to nourish the implanted cardiomyocytes, whether delivered via injection or in engineered tissues. Co-culture of hESC-derived cardiomyocytes, human endothelial cells, and human stromal cells provides a prevascular network in scaffold-free engineered tissue patches. As a result, the density of lumen structures in the graft increases by histological analysis, but perfusion of these vessels must be assessed. In this study, we develop a method for perfusing the host heart and engineered human cardiac tissue graft that is compatible with confocal microscopy for obtaining 2D images and 3D reconstructions of the graft vasculature. We demonstrate that, although vascular density is substantial in the grafts, flow remains sluggish. Further improvements in arterial remodeling or vascular engineering are required for physiological levels of blood flow.
Hypertrophy Changes 3D Shape of HiPSC-cardiomyocytes: Implications for Cellular Maturation in Regenerative Medicine Cellular and Molecular Bioengineering. | Pubmed ID: 28163790 Advances in the use of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes for heart regeneration and in vitro disease models demand a greater understanding of how these cells grow and mature in 3-dimensional space. In this study, we developed an analysis methodology of single cardiomyocytes plated on 2D surfaces to assess their 3D myofilament volume and its z-height distribution, or shape, upon hypertrophic stimulation via phenylephrine (PE) treatment or long-term culture ("aging"). Cardiomyocytes were fixed and labeled with α-actinin for confocal microscopy imaging to obtain z-stacks for 3D myofilament volume analysis. In primary neonatal rat ventricular myocytes (NRVMs), area increased 72% with PE, while volume increased 31%. In hiPSC-cardiomyocytes, area increased 70% with PE and 4-fold with aging; however, volume increased significantly only with aging by 2.3-fold. Analysis of z-height myofilament volume distribution in hiPSC-cardiomyocytes revealed a shift from a fairly uniform distribution in control cells to a basally located volume in a more flat and spread morphology with PE and even more so with aging, a shape that was akin to all NRVMs analyzed. These results suggest that 2D area is not a sufficient measure of hiPSC-cardiomyocyte growth and maturation, and that changes in 3D volume and its distribution are essential for understanding hiPSC-cardiomyocyte biology for disease modeling and regenerative medicine applications.
Laser-Etched Designs for Molding Hydrogel-Based Engineered Tissues Tissue Engineering. Part C, Methods. | Pubmed ID: 28457187 Rapid prototyping and fabrication of elastomeric molds for sterile culture of engineered tissues allow for the development of tissue geometries that can be tailored to different in vitro applications and customized as implantable scaffolds for regenerative medicine. Commercially available molds offer minimal capabilities for adaptation to unique conditions or applications versus those for which they are specifically designed. Here we describe a replica molding method for the design and fabrication of poly(dimethylsiloxane) (PDMS) molds from laser-etched acrylic negative masters with ∼0.2 mm resolution. Examples of the variety of mold shapes, sizes, and patterns obtained from laser-etched designs are provided. We use the patterned PDMS molds for producing and culturing engineered cardiac tissues with cardiomyocytes derived from human-induced pluripotent stem cells. We demonstrate that tight control over tissue morphology and anisotropy results in modulation of cell alignment and tissue-level conduction properties, including the appearance and elimination of reentrant arrhythmias, or circular electrical activation patterns. Techniques for handling engineered cardiac tissues during implantation in vivo in a rat model of myocardial infarction have been developed and are presented herein to facilitate development and adoption of surgical techniques for use with hydrogel-based engineered tissues. In summary, the method presented herein for engineered tissue mold generation is straightforward and low cost, enabling rapid design iteration and adaptation to a variety of applications in tissue engineering. Furthermore, the burden of equipment and expertise is low, allowing the technique to be accessible to all.
IGF1 and NRG1 Enhance Proliferation, Metabolic Maturity, and the Force-Frequency Response in HESC-Derived Engineered Cardiac Tissues Stem Cells International. | Pubmed ID: 28951744 Insulin-like growth factor 1 (IGF1) and neuregulin-1 (NRG1) play important roles during cardiac development both individually and synergistically. In this study, we analyze how 3D cardiac tissue engineered from human embryonic stem cell- (hESC-) derived cardiomyocytes and 2D-plated hESC-cardiomyocytes respond to developmentally relevant growth factors both to stimulate maturity and to characterize the therapeutic potential of IGF1 and NRG1. When administered to engineered cardiac tissues, a significant decrease in active force production of ~65% was measured in all treatment groups, likely due to changes in cellular physiology. Developmentally related processes were identified in engineered tissues as IGF1 increased hESC-cardiomyocyte proliferation 3-fold over untreated controls and NRG1 stimulated oxidative phosphorylation and promoted a positive force-frequency relationship in tissues up to 3 Hz. hESC-cardiomyocyte area increased significantly with NRG1 and IGF1 + NRG1 treatment in 2D culture and gene expression data suggested increased cardiac contractile components in engineered tissues, indicating the need for functional analysis in a 3D platform to accurately characterize engineered cardiac tissue response to biochemical stimulation. This study demonstrates the therapeutic potential of IGF1 for boosting proliferation and NRG1 for promoting metabolic and contractile maturation in engineered human cardiac tissue.
Integrated Approaches to Spatiotemporally Directing Angiogenesis in Host and Engineered Tissues Acta Biomaterialia. | Pubmed ID: 29371132 The field of tissue engineering has turned towards biomimicry to solve the problem of tissue oxygenation and nutrient/waste exchange through the development of vasculature. Induction of angiogenesis and subsequent development of a vascular bed in engineered tissues is actively being pursued through combinations of physical and chemical cues, notably through the presentation of topographies and growth factors. Presenting angiogenic signals in a spatiotemporal fashion is beginning to generate improved vascular networks, which will allow for the creation of large and dense engineered tissues. This review provides a brief background on the cells, mechanisms, and molecules driving vascular development (including angiogenesis), followed by how biomaterials and growth factors can be used to direct vessel formation and maturation. Techniques to accomplish spatiotemporal control of vascularization include incorporation or encapsulation of growth factors, topographical engineering, and 3D bioprinting. The vascularization of engineered tissues and their application in angiogenic therapy in vivo is reviewed herein with an emphasis on the most densely vascularized tissue of the human body - the heart.
Activation of the Unfolded Protein Response Downregulates Cardiac Ion Channels in Human Induced Pluripotent Stem Cell-derived Cardiomyocytes Journal of Molecular and Cellular Cardiology. | Pubmed ID: 29474817 Heart failure is characterized by electrical remodeling that contributes to arrhythmic risk. The unfolded protein response (UPR) is active in heart failure and can decrease protein levels by increasing mRNA decay, accelerating protein degradation, and inhibiting protein translation.