Posts Tagged: tissue engineering

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Joshua Mayourian, Delaine K. Ceholski, David M. Gonzalez, Timothy J. Cashman, Susmita Sahoo, Roger J. Hajjar, Kevin D. Costa

Endothelial–cardiomyocyte interplay through paracrine factors. Endothelial cell NO increases basal contractility via nitrosylation of L-type Ca2+ channel (LTCC) and ryanodine receptor (RyR2). NO attenuates β-adrenergic effects on cardiomyocyte excitation–contraction coupling via cGMP-dependent degradation of cAMP and protein kinase G (PKG)-mediated decrease of LTCC activity. PKG also phosphorylates troponin I, leading to myofilament calcium desensitization and thus increased lusitropy. Endothelin-1, which mainly acts through the endothelin A (ETA) receptor in ventricular cardiomyocytes, may increase calcium entry via protein kinase C (PKC)-mediated (1) increase of LTCC activity, (2) indirect activation of sodium–calcium exchanger (NCX) reverse mode by increasing Na+–H+ exchanger activity, and (3) direct activation of NCX reverse (shown) and forward (not shown) mode. Endothelin-1 alters myofilament Ca2+ sensitivity via protein kinase C/D (PKC/D) phosphorylation of troponin I and myosin-binding protein C. Finally, endothelin-1 may increase calcium-induced calcium release via inositol trisphosphate (IP3) activation of inositol trisphosphate receptor (IP3R), which sensitizes RyR2 on the sarcoplasmic reticulum (SR). Green and red arrows denote activation and inhibition, respectively. PLB indicates phospholamban; and SERCA, sarcoendoplasmic reticulum Ca2+-ATPase. [Powerpoint File]

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Joshua Mayourian, Delaine K. Ceholski, David M. Gonzalez, Timothy J. Cashman, Susmita Sahoo, Roger J. Hajjar, Kevin D. Costa

Human engineered cardiac tissue (hECT) contractility assay. A, hECTs are created, cultured, and tested in a custom bioreactor with integrated force-sensing end-posts; as the tissue beats, deflections of the end-posts are tracked. Output contractile metrics include, but are not limited to, developed force (DF), maximum rates of contraction and relaxation (+/− dF/dt, respectively), and beat rate. B, Confocal microscopy of hECTs labeled with cardiac troponin I (green) and DAPI (4’,6-diamidino-2-phenylindole; blue) displays cardiomyocytes with striated sarcomeres and regions of aligned myofibrils. Inset shows magnified view of registered sarcomeres. C, hECT labeled with sarcoendoplasmic reticulum Ca2+-ATPase 2 (red) and DAPI (blue) shows sarcoplasmic reticulum structures distributed throughout the tissue. Bar = 40 µm. [Powerpoint File]

Engineering Cardiac Muscle Tissue: A Maturating Field of Research

Engineering Cardiac Muscle Tissue: A Maturating Field of Research

Florian Weinberger, Ingra Mannhardt, Thomas Eschenhagen

Histological structure of native mouse and rat heart (longitudinal mouse heart in A; cross section of rat heart in B), engineered heart tissue (EHT) from neonatal rat heart cells (longitudinal in C, E, cross section in D), or human pluripotent stem cell–derived cardiomyocytes (F–J). A, staining of actinin (green). B, Staining of sarcolemma with wheat germ agglutinin (white in B). C and D, Staining of actinin (red in C and I), F-actin (green in D and J), or actinin and troponin T (green/red in H) and nuclei in blue (all). E, Hematoxylin and eosin–stained paraffin section. A, Reprinted from Mearini et al135 with permission of the publisher. Copyright © 2014, Macmillan Publishers Limited. B, Reprinted from Bensley et al136 with permission. Copyright © 2016, The Authors. C, D, I, and J, Reprinted from Jackman et al35 with permission of the publisher. Copyright © 2016, Elsevier; and from Eschenhagen et al134 (E) with permission of the publisher. Copyright © 2012, the American Physiological Society. F, Reprinted from Hirt et al36 with permission of the publisher. Copyright © 2014, Elsevier. G, Reprinted from Mannhardt et al78 with permission. Copyright © 2016, The Authors. H, Riegler et al93 with permission of the publisher. Copyright © 2015, American Heart Association. [Powerpoint File]

Engineering Cardiac Muscle Tissue: A Maturating Field of Research

Engineering Cardiac Muscle Tissue: A Maturating Field of Research

Florian Weinberger, Ingra Mannhardt, Thomas Eschenhagen

Plane engineered heart tissue (EHT) on Velcro-covered rods (Eschenhagen et al2, A), ring EHTs (Zimmermann et al24, B), fibrin-based mini-EHT on PDMS (polydimethylsiloxane) racks (Hansen et al25, C), cardiac micro tissues (CMT) on fluorescent pillars (Boudou et al34, D), cardiobundles on PDMS frame (Jackman et al35, Copyright © 2016, Elsevier; E), micro heart muscle (Huebsch et al81, Copyright © 2016, The Authors; F), cardiac biowires (Nunes et al131, Copyright © 2013, Nature Publishing Group; G), cardiac patch (Bian et al133, H). Please note that scale bars are only representative, and sketches might not match the exact dimensions. Graphics in A, B, and D were modified from Eschenhagen et al134 with permission of the publisher. Copyright © 2012, the American Physiological Society. [Powerpoint File]

From Microscale Devices to 3D Printing: Advances in Fabrication of 3D Cardiovascular Tissues

From Microscale Devices to 3D Printing: Advances in Fabrication of 3D Cardiovascular Tissues

Anton V. Borovjagin, Brenda M. Ogle, Joel L. Berry, Jianyi Zhang

Bioprinting is usually accomplished using a combination of gel and cells. Laser-assisted bioprinting (A) using Laser-induced forward transfer relies on the focused energy of a laser onto an energy absorbing ribbon to induce bioink droplet formation. This technique is advantageous because it avoids the problem of clogging of the bioink nozzle that plagues other bioprinting techniques. Multiphoton excitation-based printing (B) is accomplished via photocrosslinking of proteins or polymers in the focal volume of the laser and excels in its high resolution and ability to polymerize many native proteins that do not form hydrogels spontaneously outside the body. Inkjet printing (C), one of the most common printing techniques, relies on a vapor bubble or a piezoelectric actuator to displace material to extrude the bioink from a nozzle. Robotic dispensing (D) uses other mechanical means of displacing bioink under robotic control. ECM indicates extracellular matrix. [Powerpoint File]

From Microscale Devices to 3D Printing: Advances in Fabrication of 3D Cardiovascular Tissues

From Microscale Devices to 3D Printing: Advances in Fabrication of 3D Cardiovascular Tissues

Anton V. Borovjagin, Brenda M. Ogle, Joel L. Berry, Jianyi Zhang

In vitro testing of cells and tissues may occur in several ways. Microfluidic systems (A) have emerged as a tool for basic science studies of the effect of highly controlled fluid mechanical and solid mechanical forces on single cell types or cocultures. Microfluidic systems are also gaining favor as a diagnostic tool and a platform for drug development. Organoid cultures (B) are described as organ buds grown in culture that feature realistic microanatomy and are useful as cellular models of human disease. These cultures have found utility in the study of basic mechanisms of organ-specific diseases. Spheroid cultures (C) feature sphere-shaped clusters of a single cell type or coculture sustained in a gel or a bioreactor in order to interact with their 3D surroundings and are useful in testing drug efficacy and toxicity. (D) Engineered heart tissues are constructed by polymerizing an extracellular matrix–based gel containing cardiac cell types between 2 elastomeric posts or similar structures allowing auxotonic contraction of cardiomyocytes. This allows approximation of the normal conditions of the heart contracting against the hydrostatic pressure imposed by the circulation. This type of tissue construct has been used for testing toxicity of drugs and basic studies of muscle function and interplay between multiple cardiac cell types. [Powerpoint File]

Induced Pluripotent Stem Cells for Post–Myocardial Infarction Repair: Remarkable Opportunities and Challenges

Induced Pluripotent Stem Cells for Post–Myocardial Infarction Repair: Remarkable Opportunities and Challenges

Pratik A. Lalit, Derek J. Hei, Amish N. Raval, Timothy J. Kamp

Cardiac cell therapy strategies using induced pluripotent stem cells (iPSCs) and derivatives. Patient-specific primary cells are isolated and cultured in vitro from a suitable cell source, such as blood or skin. These cells are reprogrammed to iPSCs using nonintegrating strategies under Current Good Manufacturing Practice conditions. The resulting iPSCs are rigorously tested for pluripotency, genetic/epigenetic abnormalities, and safety (Tables 3 and 4). The iPSC clones that pass test criteria are banked for later use. Alternatively, allogeneic iPSCs can be used from a haplotype-matched iPSC bank. The iPSCs are then differentiated into the desired cardiac lineage cells: cardiac progenitors, cardiomyocytes (CMs), smooth muscle (SM) cells, or endothelial cells (ECs). The desired cell lineage or combination of cell lineages is transplanted into damaged heart via intracoronary/intramuscular injection or epicardially by tissue engineered cardiac patches. Ongoing studies will define the optimal cell preparations and associated delivery strategies for repair of the post–myocardial infarction heart. [Powerpoint File]

Patching the Heart: Cardiac Repair From Within and Outside

Patching the Heart: Cardiac Repair From Within and Outside

Lei Ye, Wolfram-Hubertus Zimmermann, Daniel J Garry, Jianyi Zhang

Applications of engineered heart muscle (EHM). Schematic presentation of (A) an EHM patch and (B) an EHM pouch (red). C, Illustration of a multiloop EHM with 5 loops fused together to form an asterisk-shaped stack with a solid center surrounded by 10 loops that are used for surgical fixation of the EHM graft. D, The patch was fixed over the site of infarction in rats with 6 single-knot sutures. E, The dimensions of an EHM pouch and an explanted rat heart are shown. F, An EHM pouch was implanted over a healthy rat heart to simulate its use as a biological ventricular assist device. CHF indicates congestive heart failure; and MI, myocardial infarction. C and D are adapted with permission from Zimmermann et al.23 Authorization for these adaptations has been obtained both from the owner of the copyright in the original work and from the owner of copyright in the translation or adaptation. E and F are adapted with permission from Yildirim et al.85 Authorization for these adaptations has been obtained both from the owner of the copyright in the original work and from the owner of copyright in the translation or adaptation. [Powerpoint File]

Biomaterials to Enhance Stem Cell Function in the Heart

Biomaterials to Enhance Stem Cell Function in the Heart

Vincent F.M. Segers, Richard T. Lee

Control of the biochemical and biophysical microenvironment of transplanted stem cells. Biomaterials can be used to deliver proteins (A), genes (B), or nucleotides interfering with microRNAs (miRNAs; C). D, Nanoparticles containing drugs or proteins can be linked to transplanted stem cells and provide a local depot for long-term release of growth and differentiation factors. E, Mechanical stiffness of biomaterials can guide differentiation of stem cells toward certain lineages. F, Small patterns of the biomaterial, called nanotopography, have an influence on growth and differentiation of stem cells. G, Cyclic stretch is a typical feature of the cardiovascular system and has been shown to guide stem cell differentiation toward myocytes or smooth muscle cells. H, Biomaterials can alter gene expression patterns by controlling cellular shapes. (Illustration credit: Cosmocyte/Ben Smith.) [Powerpoint File]