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Sample records for cardiac tissue sections

  1. Engineered cardiac tissues

    PubMed Central

    Iyer, Rohin K.; Chiu, Loraine L. Y.; Reis, Lewis A.; Radisic, Milica

    2011-01-01

    Cardiac tissue engineering offers the promise of creating functional tissue replacements for use in the failing heart or for in vitro drug screening. The last decade has seen a great deal of progress in this field with new advances in interdisciplinary areas such as developmental biology, genetic engineering, biomaterials, polymer science, bioreactor engineering, and stem cell biology. We review here a selection of the most recent advances in cardiac tissue engineering, including the classical cell-scaffold approaches, advanced bioreactor designs, cell sheet engineering, whole organ decellularization, stem-cell based approaches, and topographical control of tissue organization and function. We also discuss current challenges in the field, such as maturation of stem cell-derived cardiac patches and vascularization. PMID:21530228

  2. Elasticity of developing cardiac tissue

    NASA Astrophysics Data System (ADS)

    Majkut, Stephanie; Swift, Joe; Krieger, Christine; Discher, Dennis

    2011-03-01

    Proper development and function of the heart from the tissue to cellular scale depends on a compliant ECM. Here we study the maturation of embryonic cardiac tissue mechanics in parallel with the effects of extracellular mechanics on individual cardiomyocyte function throughout early development. We used micropipette aspiration to measure local and bulk elastic moduli (E) of embryonic avian heart tissue from days 2-12. We observe stiffening of the early heart tube from E = 1 kPa at day 1 to E = 2 kPa at day 4, reaching neonatal values by day 12. Treating heart tubes with blebbistatin led to 30% decrease in E, indicating a significant but partial actomyosin contribution to mechanics at these stages. We performed a proteomic analysis of intact and decellularized 2-4 day heart tubes by mass spectrometry to quantify the ECM present at these stages. Isolated cardiomyocytes from 2-4 day chick embryos were cultured on collagen-coated PA gels of various stiffnesses. Beating magnitude was modulated by substrates with E = 1-2 kPa, similar to physiological E at those stages.

  3. Cardiac Conduction through Engineered Tissue

    PubMed Central

    Choi, Yeong-Hoon; Stamm, Christof; Hammer, Peter E.; Kwaku, Kevin F.; Marler, Jennifer J.; Friehs, Ingeborg; Jones, Mara; Rader, Christine M.; Roy, Nathalie; Eddy, Mau-Thek; Triedman, John K.; Walsh, Edward P.; McGowan, Francis X.; del Nido, Pedro J.; Cowan, Douglas B.

    2006-01-01

    In children, interruption of cardiac atrioventricular (AV) electrical conduction can result from congenital defects, surgical interventions, and maternal autoimmune diseases during pregnancy. Complete AV conduction block is typically treated by implanting an electronic pacemaker device, although long-term pacing therapy in pediatric patients has significant complications. As a first step toward developing a substitute treatment, we implanted engineered tissue constructs in rat hearts to create an alternative AV conduction pathway. We found that skeletal muscle-derived cells in the constructs exhibited sustained electrical coupling through persistent expression and function of gap junction proteins. Using fluorescence in situ hybridization and polymerase chain reaction analyses, myogenic cells in the constructs were shown to survive in the AV groove of implanted hearts for the duration of the animal’s natural life. Perfusion of hearts with fluorescently labeled lectin demonstrated that implanted tissues became vascularized and immunostaining verified the presence of proteins important in electromechanical integration of myogenic cells with surrounding recipient rat cardiomyocytes. Finally, using optical mapping and electrophysiological analyses, we provide evidence of permanent AV conduction through the implant in one-third of recipient animals. Our experiments provide a proof-of-principle that engineered tissue constructs can function as an electrical conduit and, ultimately, may offer a substitute treatment to conventional pacing therapy. PMID:16816362

  4. Cardiac tissue engineering in magnetically actuated scaffolds

    NASA Astrophysics Data System (ADS)

    Sapir, Yulia; Polyak, Boris; Cohen, Smadar

    2014-01-01

    Cardiac tissue engineering offers new possibilities for the functional and structural restoration of damaged or lost heart tissue by applying cardiac patches created in vitro. Engineering such functional cardiac patches is a complex mission, involving material design on the nano- and microscale as well as the application of biological cues and stimulation patterns to promote cell survival and organization into a functional cardiac tissue. Herein, we present a novel strategy for creating a functional cardiac patch by combining the use of a macroporous alginate scaffold impregnated with magnetically responsive nanoparticles (MNPs) and the application of external magnetic stimulation. Neonatal rat cardiac cells seeded within the magnetically responsive scaffolds and stimulated by an alternating magnetic field of 5 Hz developed into matured myocardial tissue characterized by anisotropically organized striated cardiac fibers, which preserved its features for longer times than non-stimulated constructs. A greater activation of AKT phosphorylation in cardiac cell constructs after applying a short-term (20 min) external magnetic field indicated the efficacy of magnetic stimulation to actuate at a distance and provided a possible mechanism for its action. Our results point to a synergistic effect of magnetic field stimulation together with nanoparticulate features of the scaffold surface as providing the regenerating environment for cardiac cells driving their organization into functionally mature tissue.

  5. Electrical stimulation systems for cardiac tissue engineering

    PubMed Central

    Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

    2009-01-01

    We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures. PMID:19180087

  6. Three Dimension Filamentous Human Cardiac Tissue Model

    PubMed Central

    Ma, Zhen; Koo, Sangmo; Finnegan, Micaela A.; Loskill, Peter; Huebsch, Nathaniel; Marks, Natalie C.; Conklin, Bruce R.; Grigoropoulos, Costas P.; Healy, Kevin E.

    2013-01-01

    A human in vitro cardiac tissue model would be a significant advancement for understanding, studying, and developing new strategies for treating cardiac arrhythmias and related cardiovascular diseases. We developed an in vitro model of three-dimensional (3D) human cardiac tissue by populating synthetic filamentous matrices with cardiomyocytes derived from healthy wild-type volunteer (WT) and patient-specific long QT syndrome type 3 (LQT3) induced pluripotent stem cells (iPS-CMs) to mimic the condensed and aligned human ventricular myocardium. Using such a highly controllable cardiac model, we studied the contractility malfunctions associated with the electrophysiological consequences of LQT3 and their response to a panel of drugs. By varying the stiffness of filamentous matrices, LQT3 iPS-CMs exhibited different level of contractility abnormality and susceptibility to drug-induced cardiotoxicity. PMID:24268663

  7. Emergent Global Contractile Force in Cardiac Tissues.

    PubMed

    Knight, Meghan B; Drew, Nancy K; McCarthy, Linda A; Grosberg, Anna

    2016-04-12

    The heart is a complex organ whose structure and function are intricately linked at multiple length scales. Although several advancements have been achieved in the field of cardiac tissue engineering, current in vitro cardiac tissues do not fully replicate the structure or function necessary for effective cardiac therapy and cardiotoxicity studies. This is partially due to a deficiency in current understandings of cardiac tissue organization's potential downstream effects, such as changes in gene expression levels. We developed a novel (to our knowledge) in vitro tool that can be used to decouple and quantify the contribution of organization and associated downstream effects to tissue function. To do so, cardiac tissue monolayers were designed into a parquet pattern to be organized anisotropically on a local scale, within a parquet tile, and with any desired organization on a global scale. We hypothesized that if the downstream effects were muted, the relationship between developed force and tissue organization could be modeled as a sum of force vectors. With the in vitro experimental platforms of parquet tissues and heart-on-a-chip devices, we were able to prove this hypothesis for both systolic and diastolic stresses. Thus, insight was gained into the relationship between the generated stress and global myofibril organization. Furthermore, it was demonstrated that the developed quantitative tool could be used to estimate the changes in stress production due to downstream effects decoupled from tissue architecture. This has the potential to elucidate properties coupled to tissue architecture, which change force production and pumping function in the diseased heart or stem cell-derived tissues. PMID:27074686

  8. Cardiac tissue engineering using perfusion bioreactor systems

    PubMed Central

    Radisic, Milica; Marsano, Anna; Maidhof, Robert; Wang, Yadong; Vunjak-Novakovic, Gordana

    2009-01-01

    This protocol describes tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cell populations on porous scaffolds (in some cases with an array of channels) and bioreactors with perfusion of culture medium (in some cases supplemented with an oxygen carrier). The overall approach is ‘biomimetic’ in nature as it tends to provide in vivo-like oxygen supply to cultured cells and thereby overcome inherent limitations of diffusional transport in conventional culture systems. In order to mimic the capillary network, cells are cultured on channeled elastomer scaffolds that are perfused with culture medium that can contain oxygen carriers. The overall protocol takes 2–4 weeks, including assembly of the perfusion systems, preparation of scaffolds, cell seeding and cultivation, and on-line and end-point assessment methods. This model is well suited for a wide range of cardiac tissue engineering applications, including the use of human stem cells, and high-fidelity models for biological research. PMID:18388955

  9. Mechanostimulation Protocols for Cardiac Tissue Engineering

    PubMed Central

    Govoni, Marco; Muscari, Claudio; Guarnieri, Carlo; Giordano, Emanuele

    2013-01-01

    Owing to the inability of self-replacement by a damaged myocardium, alternative strategies to heart transplantation have been explored within the last decades and cardiac tissue engineering/regenerative medicine is among the present challenges in biomedical research. Hopefully, several studies witness the constant extension of the toolbox available to engineer a fully functional, contractile, and robust cardiac tissue using different combinations of cells, template bioscaffolds, and biophysical stimuli obtained by the use of specific bioreactors. Mechanical forces influence the growth and shape of every tissue in our body generating changes in intracellular biochemistry and gene expression. That is why bioreactors play a central role in the task of regenerating a complex tissue such as the myocardium. In the last fifteen years a large number of dynamic culture devices have been developed and many results have been collected. The aim of this brief review is to resume in a single streamlined paper the state of the art in this field. PMID:23936858

  10. Models of defibrillation of cardiac tissue

    NASA Astrophysics Data System (ADS)

    Krinsky, V.; Pumir, A.

    1998-03-01

    Heterogeneities, such as gap junctions, defects in periodical cellular lattices, intercellular clefts and fiber curvature allow one to understand the effect of an electric field in cardiac tissue. They induce membrane potential variations even in the bulk of the myocardium, with a characteristic sawtooth shape. The sawtooth potential, induced by heterogeneities at large scales (tissue strands) can be more easily observed, and lead to stronger effects than the one induced at the cellular level. In the generic model of propagation in cardiac tissue (FitzHugh), 4 mechanisms of defibrillation were found, two mechanisms based on excitation (EA,EM), and two—on de-excitation (DA,DM). The lowest electric field is required by an EM mechanism. In the Beeler-Reuter ionic model, mechanism DM is impossible. We critically review the experimental basis of the theory and propose new experiments.

  11. Myocardial tissue engineering for cardiac repair.

    PubMed

    Pecha, Simon; Eschenhagen, Thomas; Reichenspurner, Hermann

    2016-03-01

    The number of patients with heart failure is increasing in the aging population. Heart transplantation remains the only curative treatment option for patients with end-stage heart failure. Because of an organ donor shortage, new organ-independent treatment options are necessary. Different approaches to cardiac repair therapies have been developed and optimized in recent years. One of these promising approaches is myocardial tissue engineering, which refers to the creation of 3-dimensional engineered heart tissue in vitro. This perspective provides an overview of different approaches to tissue engineering, including essentials to improve tissue quality and choice of ideal cell source, as well as an overview of in vitro and in vivo studies. Several hurdles that have to be overcome before clinical application of engineered heart tissue might become a realistic scenario are also addressed. PMID:26856673

  12. Essentials in cardiac arrest during cesarean section.

    PubMed

    van Liempt, Susan W J D; Stoecklein, Katrin; Tjiong, Ming Y; Schwarte, Lothar A; de Groot, Christianne J M; Teunissen, Pim W

    2015-01-28

    Cardiac arrest during cesarean section is very rare. Obstetrical teams have low exposure to these critical situations necessitating frequent rehearsal and knowledge of its differential diagnosis and treatment. A 40-year-old woman pregnant with triplets underwent cesarean sections because of vaginal bleeding due to a placenta previa at 35.2 weeks of gestation. Spinal anesthesia was performed. Asystole occurred during uterotomy. Immediate resuscitation and delivery of the neonates eventually resulted in good maternal and neonatal outcomes. The differential diagnosis is essential and should include obstetric and non-obstetric causes. We describe the consideration of Bezold Jarisch reflex and amniotic fluid embolism as most appropriate in this case. PMID:25918626

  13. Distilling complexity to advance cardiac tissue engineering.

    PubMed

    Ogle, Brenda M; Bursac, Nenad; Domian, Ibrahim; Huang, Ngan F; Menasché, Philippe; Murry, Charles E; Pruitt, Beth; Radisic, Milica; Wu, Joseph C; Wu, Sean M; Zhang, Jianyi; Zimmermann, Wolfram-Hubertus; Vunjak-Novakovic, Gordana

    2016-06-01

    The promise of cardiac tissue engineering is in the ability to recapitulate in vitro the functional aspects of a healthy heart and disease pathology as well as to design replacement muscle for clinical therapy. Parts of this promise have been realized; others have not. In a meeting of scientists in this field, five central challenges or "big questions" were articulated that, if addressed, could substantially advance the current state of the art in modeling heart disease and realizing heart repair. PMID:27280684

  14. Capillary force lithography for cardiac tissue engineering.

    PubMed

    Macadangdang, Jesse; Lee, Hyun Jung; Carson, Daniel; Jiao, Alex; Fugate, James; Pabon, Lil; Regnier, Michael; Murry, Charles; Kim, Deok-Ho

    2014-01-01

    Cardiovascular disease remains the leading cause of death worldwide(1). Cardiac tissue engineering holds much promise to deliver groundbreaking medical discoveries with the aims of developing functional tissues for cardiac regeneration as well as in vitro screening assays. However, the ability to create high-fidelity models of heart tissue has proven difficult. The heart's extracellular matrix (ECM) is a complex structure consisting of both biochemical and biomechanical signals ranging from the micro- to the nanometer scale(2). Local mechanical loading conditions and cell-ECM interactions have recently been recognized as vital components in cardiac tissue engineering(3-5). A large portion of the cardiac ECM is composed of aligned collagen fibers with nano-scale diameters that significantly influences tissue architecture and electromechanical coupling(2). Unfortunately, few methods have been able to mimic the organization of ECM fibers down to the nanometer scale. Recent advancements in nanofabrication techniques, however, have enabled the design and fabrication of scalable scaffolds that mimic the in vivo structural and substrate stiffness cues of the ECM in the heart(6-9). Here we present the development of two reproducible, cost-effective, and scalable nanopatterning processes for the functional alignment of cardiac cells using the biocompatible polymer poly(lactide-co-glycolide) (PLGA)(8) and a polyurethane (PU) based polymer. These anisotropically nanofabricated substrata (ANFS) mimic the underlying ECM of well-organized, aligned tissues and can be used to investigate the role of nanotopography on cell morphology and function(10-14). Using a nanopatterned (NP) silicon master as a template, a polyurethane acrylate (PUA) mold is fabricated. This PUA mold is then used to pattern the PU or PLGA hydrogel via UV-assisted or solvent-mediated capillary force lithography (CFL), respectively(15,16). Briefly, PU or PLGA pre-polymer is drop dispensed onto a glass coverslip

  15. A modular approach to cardiac tissue engineering.

    PubMed

    Leung, Brendan M; Sefton, Michael V

    2010-10-01

    Functional cardiac tissue was prepared using a modular tissue engineering approach with the goal of creating vascularized tissue. Rat aortic endothelial cells (RAEC) were seeded onto submillimeter-sized modules made of type I bovine collagen supplemented with Matrigel™ (25% v/v) embedded with cardiomyocyte (CM)-enriched neonatal rat heart cells and assembled into a contractile, macroporous, sheet-like construct. Modules (without RAEC) cultured in 10% bovine serum (BS) were more contractile and responsive to external stimulus (lower excitation threshold, higher maximum capture rate, and greater en face fractional area changes) than modules cultured in 10% fetal BS. Incorporating 25% Matrigel in the matrix reduced the excitation threshold and increased the fractional area change relative to collagen only modules (without RAEC). A coculture medium, containing 10% BS, low Mg2+ (0.814mM), and normal glucose (5.5mM), was used to maintain RAEC junction morphology (VE-cadherin) and CM contractility, although the responsiveness of CM was attenuated with RAEC on the modules. Macroporous, sheet-like module constructs were assembled by partially immobilizing a layer of modules in alginate gel until day 8, with or without RAEC. RAEC/CM module sheets were electrically responsive; however, like modules with RAEC this responsiveness was attenuated relative to CM-only sheets. Muscle bundles coexpressing cardiac troponin I and connexin-43 were evident near the perimeter of modules and at intermodule junctions. These results suggest the potential of the modular approach as a platform for building vascularized cardiac tissue. PMID:20504074

  16. Engineered Tissue Patch for Cardiac Cell Therapy

    PubMed Central

    Zhang, Jianyi

    2015-01-01

    Opinion statement Cell therapy can be administered via injections delivered directly into the myocardium or as engineered cardiac tissue patches, which are the subject of this review. Engineered cardiac patches can be created from sheets of interconnected cells or by suspending the cells in a scaffold of material that is designed to mimic the native extracellular matrix. The sheet-based approach produces patches with well-aligned and electronically coupled cardiomyocytes, but cell-containing scaffolds are more readily vascularized by the host's circulatory system and, consequently, are currently more suitable for applications that require a thicker patch. Cell patches can also be modified for the co-delivery of peptides that may promote cell survival and activate endogenous repair mechanisms; nevertheless, techniques for controlling inflammation, limiting apoptosis, and improving vascular growth need continue to be developed to make it a therapeutic modality for patients with myocardial infarction. PMID:26122908

  17. Tissue Contraction Force Microscopy for Optimization of Engineered Cardiac Tissue.

    PubMed

    Schaefer, Jeremy A; Tranquillo, Robert T

    2016-01-01

    We developed a high-throughput screening assay that allows for relative comparison of the twitch force of millimeter-scale gel-based cardiac tissues. This assay is based on principles taken from traction force microscopy and uses fluorescent microspheres embedded in a soft polydimethylsiloxane (PDMS) substrate. A gel-forming cell suspension is simply pipetted onto the PDMS to form hemispherical cardiac tissue samples. Recordings of the fluorescent bead movement during tissue pacing are used to determine the maximum distance that the tissue can displace the elastic PDMS substrate. In this study, fibrin gel hemispheres containing human induced pluripotent stem cell-derived cardiomyocytes were formed on the PDMS and allowed to culture for 9 days. Bead displacement values were measured and compared to direct force measurements to validate the utility of the system. The amplitude of bead displacement correlated with direct force measurements, and the twitch force generated by the tissues was the same in 2 and 4 mg/mL fibrin gels, even though the 2 mg/mL samples visually appear more contractile if the assessment were made on free-floating samples. These results demonstrate the usefulness of this assay as a screening tool that allows for rapid sample preparation, data collection, and analysis in a simple and cost-effective platform. PMID:26538167

  18. Distilling complexity to advance cardiac tissue engineering

    PubMed Central

    Ogle, Brenda M.; Bursac, Nenad; Domian, Ibrahim; Huang, Ngan F; Menasché, Philippe; Murry, Charles; Pruitt, Beth; Radisic, Milica; Wu, Joseph C; Wu, Sean M; Zhang, Jianyi; Zimmermann, Wolfram-Hubertus; Vunjak-Novakovic, Gordana

    2016-01-01

    The promise of cardiac tissue engineering is in the ability to recapitulate in vitro the functional aspects of healthy heart and disease pathology as well as to design replacement muscle for clinical therapy. Parts of this promise have been realized; others have not. In a meeting of scientists in this field, five central challenges or “big questions” were articulated that, if addressed, could substantially advance the current state-of-the-art in modeling heart disease and realizing heart repair. PMID:27280684

  19. Heart Regeneration with Embryonic Cardiac Progenitor Cells and Cardiac Tissue Engineering

    PubMed Central

    Tian, Shuo; Liu, Qihai; Gnatovskiy, Leonid; Ma, Peter X.; Wang, Zhong

    2015-01-01

    Myocardial infarction (MI) is the leading cause of death worldwide. Recent advances in stem cell research hold great potential for heart tissue regeneration through stem cell-based therapy. While multiple cell types have been transplanted into MI heart in preclinical studies or clinical trials, reduction of scar tissue and restoration of cardiac function have been modest. Several challenges hamper the development and application of stem cell-based therapy for heart regeneration. Application of cardiac progenitor cells (CPCs) and cardiac tissue engineering for cell therapy has shown great promise to repair damaged heart tissue. This review presents an overview of the current applications of embryonic CPCs and the development of cardiac tissue engineering in regeneration of functional cardiac tissue and reduction of side effects for heart regeneration. We aim to highlight the benefits of the cell therapy by application of CPCs and cardiac tissue engineering during heart regeneration. PMID:26744736

  20. Spatially Extended Memory Models of Cardiac Tissue

    NASA Astrophysics Data System (ADS)

    Fox, Jeffrey; Riccio, Mark; Hua, Fei; Bodenschatz, Eberhard; Gilmour, Robert

    2002-03-01

    Beat-to-beat alternation of cardiac electrical properties (alternans) commonly occurs during rapid periodic pacing. Although alternans is generally associated with a resititution curve with slope >=1, recent studies by Gauthier and co-workers reported the absence of alternans in frog heart tissue with a restitution curve of slope >=1. These experimental findings were understood in terms of a memory model in which the duration D of an action potential depends on the preceding rest interval I as well as a memory variable M that accumulates during D and dissipates during I. We study the spatiotemporal dynamics of a spatially extended 1-d fiber using an ionic model that exhibits memory effects. We find that while a single cell can have a restitution slope >=1 and not show alternans (because of memory), the spatially extended system exhibits alternans. To understand the dynamical mechanism of this behavior, we study a coupled maps memory model both numerically and analytically. These results illustrate that spatial effects and memory effects can play a significant role in determining the dynamics of wave propagation in cardiac tissue.

  1. Cardiac tissue slices: preparation, handling, and successful optical mapping.

    PubMed

    Wang, Ken; Lee, Peter; Mirams, Gary R; Sarathchandra, Padmini; Borg, Thomas K; Gavaghan, David J; Kohl, Peter; Bollensdorff, Christian

    2015-05-01

    Cardiac tissue slices are becoming increasingly popular as a model system for cardiac electrophysiology and pharmacology research and development. Here, we describe in detail the preparation, handling, and optical mapping of transmembrane potential and intracellular free calcium concentration transients (CaT) in ventricular tissue slices from guinea pigs and rabbits. Slices cut in the epicardium-tangential plane contained well-aligned in-slice myocardial cell strands ("fibers") in subepicardial and midmyocardial sections. Cut with a high-precision slow-advancing microtome at a thickness of 350 to 400 μm, tissue slices preserved essential action potential (AP) properties of the precutting Langendorff-perfused heart. We identified the need for a postcutting recovery period of 36 min (guinea pig) and 63 min (rabbit) to reach 97.5% of final steady-state values for AP duration (APD) (identified by exponential fitting). There was no significant difference between the postcutting recovery dynamics in slices obtained using 2,3-butanedione 2-monoxime or blebistatin as electromechanical uncouplers during the cutting process. A rapid increase in APD, seen after cutting, was caused by exposure to ice-cold solution during the slicing procedure, not by tissue injury, differences in uncouplers, or pH-buffers (bicarbonate; HEPES). To characterize intrinsic patterns of CaT, AP, and conduction, a combination of multipoint and field stimulation should be used to avoid misinterpretation based on source-sink effects. In summary, we describe in detail the preparation, mapping, and data analysis approaches for reproducible cardiac tissue slice-based investigations into AP and CaT dynamics. PMID:25595366

  2. Cardiac tissue slices: preparation, handling, and successful optical mapping

    PubMed Central

    Wang, Ken; Lee, Peter; Mirams, Gary R.; Sarathchandra, Padmini; Borg, Thomas K.; Gavaghan, David J.; Kohl, Peter

    2015-01-01

    Cardiac tissue slices are becoming increasingly popular as a model system for cardiac electrophysiology and pharmacology research and development. Here, we describe in detail the preparation, handling, and optical mapping of transmembrane potential and intracellular free calcium concentration transients (CaT) in ventricular tissue slices from guinea pigs and rabbits. Slices cut in the epicardium-tangential plane contained well-aligned in-slice myocardial cell strands (“fibers”) in subepicardial and midmyocardial sections. Cut with a high-precision slow-advancing microtome at a thickness of 350 to 400 μm, tissue slices preserved essential action potential (AP) properties of the precutting Langendorff-perfused heart. We identified the need for a postcutting recovery period of 36 min (guinea pig) and 63 min (rabbit) to reach 97.5% of final steady-state values for AP duration (APD) (identified by exponential fitting). There was no significant difference between the postcutting recovery dynamics in slices obtained using 2,3-butanedione 2-monoxime or blebistatin as electromechanical uncouplers during the cutting process. A rapid increase in APD, seen after cutting, was caused by exposure to ice-cold solution during the slicing procedure, not by tissue injury, differences in uncouplers, or pH-buffers (bicarbonate; HEPES). To characterize intrinsic patterns of CaT, AP, and conduction, a combination of multipoint and field stimulation should be used to avoid misinterpretation based on source-sink effects. In summary, we describe in detail the preparation, mapping, and data analysis approaches for reproducible cardiac tissue slice-based investigations into AP and CaT dynamics. PMID:25595366

  3. Enabling microscale and nanoscale approaches for bioengineered cardiac tissue.

    PubMed

    Chan, Vincent; Raman, Ritu; Cvetkovic, Caroline; Bashir, Rashid

    2013-03-26

    In this issue of ACS Nano, Shin et al. present their finding that the addition of carbon nanotubes (CNT) in gelatin methacrylate (GelMA) results in improved functionality of bioengineered cardiac tissue. These CNT-GelMA hybrid materials demonstrate cardiac tissue with enhanced electrophysiological performance; improved mechanical integrity; better cell adhesion, viability, uniformity, and organization; increased beating rate and lowered excitation threshold; and protective effects against cardio-inhibitory and cardio-toxic drugs. In this Perspective, we outline recent progress in cardiac tissue engineering and prospects for future development. Bioengineered cardiac tissues can be used to build "heart-on-a-chip" devices for drug safety and efficacy testing, fabricate bioactuators for biointegrated robotics and reverse-engineered life forms, treat abnormal cardiac rhythms, and perhaps one day cure heart disease with tissue and organ transplants. PMID:23527748

  4. Biomaterial based cardiac tissue engineering and its applications

    PubMed Central

    Huyer, Locke Davenport; Montgomery, Miles; Zhao, Yimu; Xiao, Yun; Conant, Genevieve; Korolj, Anastasia; Radisic, Milica

    2015-01-01

    Cardiovascular disease is a leading cause of death worldwide, necessitating the development of effective treatment strategies. A myocardial infarction involves the blockage of a coronary artery leading to depletion of nutrient and oxygen supply to cardiomyocytes and massive cell death in a region of the myocardium. Cardiac tissue engineering is the growth of functional cardiac tissue in vitro on biomaterial scaffolds for regenerative medicine application. This strategy relies on the optimization of the complex relationship between cell networks and biomaterial properties. In this review, we discuss important biomaterial properties for cardiac tissue engineering applications, such as elasticity, degradation, and induced host response, and their relationship to engineered cardiac cell environments. With these properties in mind, we also emphasize in vitro use of cardiac tissues for high-throughput drug screening and disease modelling. PMID:25989939

  5. Biomaterial based cardiac tissue engineering and its applications.

    PubMed

    Huyer, Locke Davenport; Montgomery, Miles; Zhao, Yimu; Xiao, Yun; Conant, Genevieve; Korolj, Anastasia; Radisic, Milica

    2015-06-01

    Cardiovascular disease is a leading cause of death worldwide, necessitating the development of effective treatment strategies. A myocardial infarction involves the blockage of a coronary artery leading to depletion of nutrient and oxygen supply to cardiomyocytes and massive cell death in a region of the myocardium. Cardiac tissue engineering is the growth of functional cardiac tissue in vitro on biomaterial scaffolds for regenerative medicine application. This strategy relies on the optimization of the complex relationship between cell networks and biomaterial properties. In this review, we discuss important biomaterial properties for cardiac tissue engineering applications, such as elasticity, degradation, and induced host response, and their relationship to engineered cardiac cell environments. With these properties in mind, we also emphasize in vitro use of cardiac tissues for high-throughput drug screening and disease modelling. PMID:25989939

  6. Incretin attenuates diabetes-induced damage in rat cardiac tissue.

    PubMed

    AbdElmonem Elbassuoni, Eman

    2014-09-01

    Glucagon-like peptide-1 (GLP-1), as a member of the incretin family, has a role in glucose homeostasis, its receptors distributed throughout the body, including the heart. The aim was to investigate cardiac lesions following diabetes induction, and the potential effect of GLP-1 on this type of lesions and the molecular mechanism driving this activity. Adult male rats were classified into: normal, diabetic, 4-week high-dose exenatide-treated diabetic rats, 4-week low-dose exenatide-treated diabetic rats, and 1-week exenatide-treated diabetic rats. The following parameters were measured: in blood: glucose, insulin, lactate dehydrogenase (LDH), total creatine kinase (CK), creatine kinase MB isoenzyme (CK-MB), and CK-MB relative index; in cardiac tissue: lipid peroxide (LPO) and some antioxidant enzymes. The untreated diabetic group displayed significant increases in blood level of glucose, LDH, and CK-MB, and cardiac tissue LPO, and a significant decrease in cardiac tissue antioxidant enzymes. GLP-1 supplementation in diabetic rats definitely decreased the hyperglycemia and abolished the detrimental effects of diabetes on the cardiac tissue. The effect of GLP-1 on blood glucose and on the heart also appeared after a short supplementation period (1 week). It can be concluded that GLP-1 has beneficial effects on diabetes-induced oxidative cardiac tissue damage, most probably via its antioxidant effect directly acting on cardiac tissue and independent of its hypoglycemic effect. PMID:25011640

  7. Bioactive polymers for cardiac tissue engineering

    NASA Astrophysics Data System (ADS)

    Wall, Samuel Thomas

    2007-05-01

    Prevalent in the US and worldwide, acute myocardial infarctions (AMI) can cause ischemic injuries to the heart that persist and lead to progressive degradation of the organ. Tissue engineering techniques exploiting biomaterials present a hopeful means of treating these injuries, either by mechanically stabilizing the injured ventricle, or by fostering cell growth to replace myocytes lost to damage. This thesis describes the development and testing of a synthetic extracellular matrix for cardiac tissue engineering applications. The first stage of this process was using an advanced finite element model of an injured ovine left ventricle to evaluate the potential benefits of injecting synthetic materials into the heart. These simulations indicated that addition of small amounts non-contractile material (on the order of 1--5% total wall volume) to infarct border zone regions reduced pathological systolic fiber stress to levels near those found in normal remote regions. Simulations also determined that direct addition to the infarct itself caused increases in ventricle ejection fraction while the underlying performance of the pump, ascertained by the Starling relation, was not improved. From these theoretical results, biomaterials were developed specifically for injection into the injured myocardium, and were characterized and tested for their mechanical properties and ability to sustain the proliferation of a stem cell population suitable for transplantation. Thermoresponsive synthetic copolymer hydrogels consisting of N-isopropylacrylamide and acrylic acid, p(NIPAAm-co-AAc), crosslinked with protease degradable amino acid sequences and modified with integrin binding ligands were synthesized, characterized in vitro, and used for myocardial implantation. These injectable materials could maintain a population of bone marrow derived mesenchymal stem cells in both two dimensional and three dimensional culture, and when tested in vivo in a murine infarct model they

  8. Micromolded Gelatin Hydrogels for Extended Culture of Engineered Cardiac Tissues

    PubMed Central

    McCain, Megan L.; Agarwal, Ashutosh; Nesmith, Haley W.; Nesmith, Alexander P.; Parker, Kevin Kit

    2014-01-01

    Defining the chronic cardiotoxic effects of drugs during preclinical screening is hindered by the relatively short lifetime of functional cardiac tissues in vitro, which are traditionally cultured on synthetic materials that do not recapitulate the cardiac microenvironment. Because collagen is the primary extracellular matrix protein in the heart, we hypothesized that micromolded gelatin hydrogel substrates tuned to mimic the elastic modulus of the heart would extend the lifetime of engineered cardiac tissues by better matching the native chemical and mechanical microenvironment. To measure tissue stress, we used tape casting, micromolding, and laser engraving to fabricate gelatin hydrogel muscular thin film cantilevers. Neonatal rat cardiac myocytes adhered to gelatin hydrogels and formed aligned tissues as defined by the microgrooves. Cardiac tissues could be cultured for over three weeks without declines in contractile stress. Myocytes on gelatin had higher spare respiratory capacity compared to those on fibronectin-coated PDMS, suggesting that improved metabolic function could be contributing to extended culture lifetime. Lastly, human induced pluripotent stem cell-derived cardiac myocytes adhered to micromolded gelatin surfaces and formed aligned tissues that remained functional for four weeks, highlighting their potential for human-relevant chronic studies. PMID:24731714

  9. Mitogen-activated protein kinase (MAPK) in cardiac tissues.

    PubMed

    Page, C; Doubell, A F

    Mitogen-activated protein kinase (MAPK) has recently emerged as a prominent role player in intracellular signalling in the ventricular myocyte with attention being focussed on its possible role in the development of ventricular hypertrophy. It is becoming clear that MAPK is also active in other cells of cardiac origin such as cardiac fibroblasts and possible functions of this signalling pathway in the heart have yet to be explored. In this report the mammalian MAPK pathway is briefly outlined, before reviewing current knowledge of the MAPK pathway in cardiac tissue (ventricular myocytes, vascular smooth muscle cells and cardiac fibroblasts). New data is also presented on the presence and activity of MAPK in two additional cardiac celltypes namely atrial myocytes and vascular endothelial cells from the coronary microcirculation. PMID:8739228

  10. Anisotropic Silk Biomaterials Containing Cardiac Extracellular Matrix for Cardiac Tissue Engineering

    PubMed Central

    Stoppel, Whitney L.; Hu, Dongjian; Domian, Ibrahim J.; Kaplan, David L.; Black, Lauren D.

    2015-01-01

    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 mm × 5 mm × 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. PMID:25826196

  11. Self-organization of rat cardiac cells into contractile 3-D cardiac tissue.

    PubMed

    Baar, Keith; Birla, Ravi; Boluyt, Marvin O; Borschel, Gregory H; Arruda, Ellen M; Dennis, Robert G

    2005-02-01

    The mammalian heart is not known to regenerate following injury. Therefore, there is great interest in developing viable tissue-based models for cardiac assist. Recent years have brought numerous advances in the development of scaffold-based models of cardiac tissue, but a self-organizing model has yet to be described. Here, we report the development of an in vitro cardiac tissue without scaffolding materials in the contractile region. Using an optimal concentration of the adhesion molecule laminin, a confluent layer of neonatal rat cardiomyogenic cells can be induced to self-organize into a cylindrical construct, resembling a papillary muscle, which we have termed a cardioid. Like endogenous heart tissue, cardioids contract spontaneously and can be electrically paced between 1 and 5 Hz indefinitely without fatigue. These engineered cardiac tissues also show an increased rate of spontaneous contraction (chronotropy), increased rate of relaxation (lusitropy), and increased force production (inotropy) in response to epinephrine. Cardioids have a developmental protein phenotype that expresses both alpha- and beta-tropomyosin, very low levels of SERCA2a, and very little of the mature isoform of cardiac troponin T. PMID:15574489

  12. Cardiac Cell Culture Model (CCCM) as a Left Ventricle Mimic for Cardiac Tissue Generation

    PubMed Central

    Nguyen, Mai-Dung; Tinney, Joseph P.; Yuan, Fangping; Roussel, Thomas J.; El-Baz, Ayman; Giridharan, Guruprasad; Keller, Bradley B.; Sethu, Palaniappan

    2013-01-01

    A major challenge in cardiac tissue engineering is the delivery of hemodynamic mechanical cues that play a critical role in the early development and maturation of cardiomyocytes. Generation of functional cardiac tissue capable of replacing or augmenting cardiac function therefore requires physiologically relevant environments that can deliver complex mechanical cues for cardiomyocyte functional maturation. The goal of this work is the development and validation of a cardiac cell culture model (CCCM) microenvironment that accurately mimics pressure-volume changes seen in the left ventricle and to use this system to achieve cardiac cell maturation under conditions where mechanical loads such as pressure and stretch are gradually increased from the unloaded state to conditions seen in vivo. The CCCM platform, consisting of a cell culture chamber integrated within a flow loop was created to accomplish culture of 10 day chick embryonic ventricular cardiomyocytes subject to 4 days of stimulation (10 mm Hg, ~13% stretch at a frequency of 2 Hz). Results clearly show that CCCM conditioned cardiomyocytes accelerate cardiomyocyte structural and functional maturation in comparison to static unloaded controls as evidenced by increased proliferation, alignment of actin cytoskeleton, bundle-like sarcomeric α-actinin expression, higher pacing beat rate at lower threshold voltages and increased shortening. These results confirm the CCCM microenvironment can accelerate immature cardiac cell structural and functional maturation for potential cardiac regenerative applications. PMID:23952579

  13. Construction of cardiac tissue rings using a magnetic tissue fabrication technique.

    PubMed

    Akiyama, Hirokazu; Ito, Akira; Sato, Masanori; Kawabe, Yoshinori; Kamihira, Masamichi

    2010-01-01

    Here we applied a magnetic force-based tissue engineering technique to cardiac tissue fabrication. A mixture of extracellular matrix precursor and cardiomyocytes labeled with magnetic nanoparticles was added into a well containing a central polycarbonate cylinder. With the use of a magnet, the cells were attracted to the bottom of the well and allowed to form a cell layer. During cultivation, the cell layer shrank towards the cylinder, leading to the formation of a ring-shaped tissue that possessed a multilayered cell structure and contractile properties. These results indicate that magnetic tissue fabrication is a promising approach for cardiac tissue engineering. PMID:21152282

  14. Controlling the Structural and Functional Anisotropy of Engineered Cardiac Tissues

    PubMed Central

    Bursac, N

    2014-01-01

    The ability to control the degree of structural and functional anisotropy in 3D engineered cardiac tissues would have high utility for both in vitro studies of cardiac muscle physiology and pathology as well as potential tissue engineering therapies for myocardial infarction. Here, we applied a high aspect ratio soft lithography technique to generate network-like tissue patches seeded with neonatal rat cardiomyocytes. Fabricating longer elliptical pores within the patch networks increased the overall cardiomyocyte and extracellular matrix (ECM) alignment within the patch. Improved uniformity of cell and matrix alignment yielded an increase in anisotropy of action potential propagation and faster longitudinal conduction velocity (LCV). Cardiac tissue patches with a higher degree of cardiomyocyte alignment and electrical anisotropy also demonstrated greater isometric twitch forces. After two weeks of culture, specific measures of electrical and contractile function (LCV = 26.8 ± 0.8 cm/s, specific twitch force = 8.9 ± 1.1 mN/mm2 for the longest pores studied) were comparable to those of neonatal rat myocardium. We have thus described methodology for engineering of highly functional 3D engineered cardiac tissues with controllable degree of anisotropy. PMID:24717534

  15. Spring-like fibers for cardiac tissue engineering.

    PubMed

    Fleischer, Sharon; Feiner, Ron; Shapira, Assaf; Ji, Jing; Sui, Xiaomeng; Daniel Wagner, H; Dvir, Tal

    2013-11-01

    Recapitulation of the cellular microenvironment of the heart, which promotes cell contraction, remains a key challenge in cardiac tissue engineering. We report here on our work, where for the first time, a 3-dimensional (3D) spring-like fiber scaffold was fabricated, successfully mimicking the coiled perimysial fibers of the heart. We hypothesized that since in vivo straightening and re-coiling of these fibers allow stretching and contraction of the myocardium in the direction of the cardiomyocytes, such a scaffold can support the assembly of a functional cardiac tissue capable of generating a strong contraction force. In this study, the mechanical properties of both spring-like single fibers and 3D scaffolds composed of them were investigated. The measurements showed that they have increased elasticity and extensibility compared to corresponding straight fibers and straight fiber scaffolds. We have also shown that cardiac cells cultivated on single spring-like fibers formed cell-fiber interactions that induced fiber stretching in the direction of contraction. Moreover, cardiac cells engineered within 3D thick spring-like fiber scaffolds formed a functional tissue exhibiting significantly improved function, including stronger contraction force (p = 0.002), higher beating rate (p < 0.0001) and lower excitation threshold (p = 0.02), compared to straight fiber scaffolds. Collectively, our results suggest that spring-like fibers can play a key role in contributing to the ex vivo formation of a contracting cardiac muscle tissue. We envision that cardiac tissues engineered within these spring-like fiber scaffolds can be used to improve heart function after infarction. PMID:23953840

  16. Polycaprolactone/oligomer compound scaffolds for cardiac tissue engineering.

    PubMed

    Reddy, Chaganti Srinivasa; Venugopal, Jayarama Reddy; Ramakrishna, Seeram; Zussman, Eyal

    2014-10-01

    Polycaprolactone (PCL), a synthetic biocompatible and biodegradable polymer generally used as a scaffold material for tissue engineering applications. The high stiffness and hydrophobicity of the PCL fiber mesh does not provide significant cell attachment and proliferation in cardiac tissue engineering. Towards this goal, the study focused on a compound of PCL and oligomer hydrogel [Bisphenol A ethoxylated dimethacrylate (BPAEDMA)] processed into electrospun nanofibrous scaffolds. The composition, morphology and mechanical properties of the compound scaffolds, composed of varying ratios of PCL and hydrogel were characterized by scanning electron microscopy, infrared spectroscopy and dynamic mechanical analyzer. The elastic modulus of PCL/BPAEDMA nanofibrous scaffolds was shown to be varying the BPAEDMA weight fraction and was decreased by increasing the BPAEDMA weight fraction. Compound fiber meshes containing 75 wt % BPAEDMA oligomer hydrogel exhibited lower modulus (3.55 MPa) and contact angle of 25(o) . Rabbit cardiac cells cultured for 10 days on these PCL/BPAEDMA compound nanofibrous scaffolds remained viable and expressed cardiac troponin and alpha-actinin proteins for the normal functioning of myocardium. Cell adhesion and proliferations were significantly increased on compound fiber meshes containing 75 wt % BPAEDMA, when compared with other nanofibrous scaffolds. The results observed that the produced PCL/BPAEDMA compound nanofibrous scaffolds promote cell adhesion, proliferation and normal functioning of cardiac cells to clinically beneficial levels, relevant for cardiac tissue engineering. PMID:24288184

  17. Transplantation of a tissue-engineered human vascularized cardiac muscle.

    PubMed

    Lesman, Ayelet; Habib, Manhal; Caspi, Oren; Gepstein, Amira; Arbel, Gil; Levenberg, Shulamit; Gepstein, Lior

    2010-01-01

    Myocardial regeneration strategies have been hampered by the lack of sources for human cardiomyocytes (CMs) and by the significant donor cell loss following transplantation. We assessed the ability of a three-dimensional tissue-engineered human vascularized cardiac muscle to engraft in the in vivo rat heart and to promote functional vascularization. Human embryonic stem cell-derived CMs alone or with human endothelial cells (human umbilical vein endothelial cells) and embryonic fibroblasts (triculture constructs) were seeded onto biodegradable porous scaffolds. The resulting tissue constructs were transplanted to the in vivo rat heart and formed cardiac tissue grafts. Immunostaining studies for human-specific CD31 and alpha-smooth muscle actin demonstrated the formation of both donor (human) and host (rat)-derived vasculature within the engrafted triculture tissue constructs. Intraventricular injection of fluorescent microspheres or lectin resulted in their incorporation by human-derived vessels, confirming their functional integration with host coronary vasculature. Finally, the number of blood vessels was significantly greater in the triculture tissue constructs (60.3 +/- 8/mm(3), p < 0.05) when compared with scaffolds containing only CMs (39.0 +/- 14.4/mm(3)). In conclusion, a tissue-engineered human vascularized cardiac muscle can be established ex vivo and transplanted in vivo to form stable grafts. By utilizing a multicellular preparation we were able to increase biograft vascularization and to show that the preexisting human vessels can become functional and contribute to tissue perfusion. PMID:19642856

  18. Cardiac tissue characterization using near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Singh Moon, Rajinder; Hendon, Christine P.

    2014-03-01

    Cardiac tissue from swine and canine hearts were assessed using diffuse reflectance near-infrared spectroscopy (NIRS) ex vivo. Slope measured between 800-880 nm reflectance was found to reveal differences between epicardial fat and normal myocardium tissue. This parameter was observed to increase monotonically from measurements obtained from the onset of radiofrequency ablation (RFA). A sheathe-style fiber optic catheter was then developed to allow real-time sampling of the zone of resistive heating during RFA treatment. A model was developed and used to extract changes in tissue absorption and reduced scattering based on the steady-state diffusion approximation. It was found that key changes in tissue optical properties occur during application of RF energy and can be monitored using NIRS. These results encourage the development of NIRS integrated catheters for real-time guidance of the cardiac ablation treatment.

  19. Connective tissue growth factor induces cardiac hypertrophy through Akt signaling

    SciTech Connect

    Hayata, Nozomi; Fujio, Yasushi; Yamamoto, Yasuhiro; Iwakura, Tomohiko; Obana, Masanori; Takai, Mika; Mohri, Tomomi; Nonen, Shinpei; Maeda, Makiko; Azuma, Junichi

    2008-05-30

    In the process of cardiac remodeling, connective tissue growth factor (CTGF/CCN2) is secreted from cardiac myocytes. Though CTGF is well known to promote fibroblast proliferation, its pathophysiological effects in cardiac myocytes remain to be elucidated. In this study, we examined the biological effects of CTGF in rat neonatal cardiomyocytes. Cardiac myocytes stimulated with full length CTGF and its C-terminal region peptide showed the increase in cell surface area. Similar to hypertrophic ligands for G-protein coupled receptors, such as endothelin-1, CTGF activated amino acid uptake; however, CTGF-induced hypertrophy is not associated with the increased expression of skeletal actin or BNP, analyzed by Northern-blotting. CTGF treatment activated ERK1/2, p38 MAPK, JNK and Akt. The inhibition of Akt by transducing dominant-negative Akt abrogated CTGF-mediated increase in cell size, while the inhibition of MAP kinases did not affect the cardiac hypertrophy. These findings indicate that CTGF is a novel hypertrophic factor in cardiac myocytes.

  20. Biomimetic Polymers for Cardiac Tissue Engineering

    PubMed Central

    2016-01-01

    Heart failure is a morbid disorder characterized by progressive cardiomyocyte (CM) dysfunction and death. Interest in cell-based therapies is growing, but sustainability of injected CMs remains a challenge. To mitigate this, we developed an injectable biomimetic Reverse Thermal Gel (RTG) specifically engineered to support long-term CM survival. This RTG biopolymer provided a solution-based delivery vehicle of CMs, which transitioned to a gel-based matrix shortly after reaching body temperature. In this study we tested the suitability of this biopolymer to sustain CM viability. The RTG was biomolecule-functionalized with poly-l-lysine or laminin. Neonatal rat ventricular myocytes (NRVM) and adult rat ventricular myocytes (ARVM) were cultured in plain-RTG and biomolecule-functionalized-RTG both under 3-dimensional (3D) conditions. Traditional 2D biomolecule-coated dishes were used as controls. We found that the RTG-lysine stimulated NRVM to spread and form heart-like functional syncytia. Regarding cell contraction, in both RTG and RTG-lysine, beating cells were recorded after 21 days. Additionally, more than 50% (p value < 0.05; n = 5) viable ARVMs, characterized by a well-defined cardiac phenotype represented by sarcomeric cross-striations, were found in the RTG-laminin after 8 days. These results exhibit the tremendous potential of a minimally invasive CM transplantation through our designed RTG-cell therapy platform. PMID:27073119

  1. Cardiac Tissue Injury and Remodeling Is Dependent Upon MR Regulation of Activation Pathways in Cardiac Tissue Macrophages.

    PubMed

    Shen, Jimmy Z; Morgan, James; Tesch, Greg H; Rickard, Amanda J; Chrissobolis, Sophocles; Drummond, Grant R; Fuller, Peter J; Young, Morag J

    2016-08-01

    Macrophage mineralocorticoid receptor (MR) signaling is an important mediator of cardiac tissue inflammation and fibrosis. The goal of the present study was to determine the cellular mechanisms of MR signaling in macrophages that promote cardiac tissue injury and remodeling. We sought to identify specific markers of MR signaling in isolated tissue macrophages (cardiac, aortic) vs splenic mononuclear cells from wild-type and myeloid MR-null mice given vehicle/salt or deoxycorticosterone (DOC)/salt for 8 weeks. Cardiac tissue fibrosis in response to 8 weeks of DOC/salt treatment was found in the hearts from wild-type but not myeloid MR-null mice. This was associated with an increased expression of the profibrotic markers TGF-β1 and matrix metalloproteinase-12 and type 1 inflammatory markers TNFα and chemokine (C-X-C motif) ligand-9 in cardiac macrophages. Differential expression of immunomodulatory M2-like markers (eg, arginase-1, macrophage scavenger receptor 1) was dependent on the tissue location of wild-type and MR-null macrophages. Finally, intact MR signaling is required for the phosphorylation of c-Jun NH2-terminal kinase in response to a proinflammatory stimulus in bone marrow monocytes/macrophages in culture. These data suggest that the activation of the c-Jun NH2-terminal kinase pathway in macrophages after a tissue injury and inflammatory stimuli in the DOC/salt model is MR dependent and regulates the transcription of downstream profibrotic factors, which may represent potential therapeutic targets in heart failure patients. PMID:27253999

  2. Electroactive 3D materials for cardiac tissue engineering

    NASA Astrophysics Data System (ADS)

    Gelmi, Amy; Zhang, Jiabin; Cieslar-Pobuda, Artur; Ljunngren, Monika K.; Los, Marek Jan; Rafat, Mehrdad; Jager, Edwin W. H.

    2015-04-01

    By-pass surgery and heart transplantation are traditionally used to restore the heart's functionality after a myocardial Infarction (MI or heart attack) that results in scar tissue formation and impaired cardiac function. However, both procedures are associated with serious post-surgical complications. Therefore, new strategies to help re-establish heart functionality are necessary. Tissue engineering and stem cell therapy are the promising approaches that are being explored for the treatment of MI. The stem cell niche is extremely important for the proliferation and differentiation of stem cells and tissue regeneration. For the introduction of stem cells into the host tissue an artificial carrier such as a scaffold is preferred as direct injection of stem cells has resulted in fast stem cell death. Such scaffold will provide the proper microenvironment that can be altered electronically to provide temporal stimulation to the cells. We have developed an electroactive polymer (EAP) scaffold for cardiac tissue engineering. The EAP scaffold mimics the extracellular matrix and provides a 3D microenvironment that can be easily tuned during fabrication, such as controllable fibre dimensions, alignment, and coating. In addition, the scaffold can provide electrical and electromechanical stimulation to the stem cells which are important external stimuli to stem cell differentiation. We tested the initial biocompatibility of these scaffolds using cardiac progenitor cells (CPCs), and continued onto more sensitive induced pluripotent stem cells (iPS). We present the fabrication and characterisation of these electroactive fibres as well as the response of increasingly sensitive cell types to the scaffolds.

  3. Fourier transform infrared spectroscopic imaging of cardiac tissue to detect collagen deposition after myocardial infarction

    NASA Astrophysics Data System (ADS)

    Cheheltani, Rabee; Rosano, Jenna M.; Wang, Bin; Sabri, Abdel Karim; Pleshko, Nancy; Kiani, Mohammad F.

    2012-05-01

    Myocardial infarction often leads to an increase in deposition of fibrillar collagen. Detection and characterization of this cardiac fibrosis is of great interest to investigators and clinicians. Motivated by the significant limitations of conventional staining techniques to visualize collagen deposition in cardiac tissue sections, we have developed a Fourier transform infrared imaging spectroscopy (FT-IRIS) methodology for collagen assessment. The infrared absorbance band centered at 1338 cm-1, which arises from collagen amino acid side chain vibrations, was used to map collagen deposition across heart tissue sections of a rat model of myocardial infarction, and was compared to conventional staining techniques. Comparison of the size of the collagen scar in heart tissue sections as measured with this methodology and that of trichrome staining showed a strong correlation (R=0.93). A Pearson correlation model between local intensity values in FT-IRIS and immuno-histochemical staining of collagen type I also showed a strong correlation (R=0.86). We demonstrate that FT-IRIS methodology can be utilized to visualize cardiac collagen deposition. In addition, given that vibrational spectroscopic data on proteins reflect molecular features, it also has the potential to provide additional information about the molecular structure of cardiac extracellular matrix proteins and their alterations.

  4. Cell electrospinning cardiac patches for tissue engineering the heart.

    PubMed

    Ehler, Elisabeth; Jayasinghe, Suwan N

    2014-09-21

    Cell electrospinning has tremendous applicability to a wide range of uses within both the laboratory and clinic. This has directly resulted from the technology's unique ability to immobilize multiple cell types with a wide range of molecules simultaneously within a fiber during the scaffold generation process. The technology has been shown to generate many cell laden complex architectures from true three-dimensional sheets to those multi-core vessels. Although those studies have demonstrated the versatility of this platform biotechnology, we show here for the first time the ability to immobilize primary cardiac myocytes within these fibers in our quest to develop this technology for creating three-dimensional cardiac patches which could be used for repairing, replacing and rejuvenating damaged, diseased and/or ageing cardiac tissues. These advances are unrivalled by any other technology currently available in the regenerative medicine toolbox, and have many interesting ramifications for repairing a damaged heart. PMID:25058315

  5. Cardiac tissue engineering and regeneration using cell-based therapy

    PubMed Central

    Alrefai, Mohammad T; Murali, Divya; Paul, Arghya; Ridwan, Khalid M; Connell, John M; Shum-Tim, Dominique

    2015-01-01

    Stem cell therapy and tissue engineering represent a forefront of current research in the treatment of heart disease. With these technologies, advancements are being made into therapies for acute ischemic myocardial injury and chronic, otherwise nonreversible, myocardial failure. The current clinical management of cardiac ischemia deals with reestablishing perfusion to the heart but not dealing with the irreversible damage caused by the occlusion or stenosis of the supplying vessels. The applications of these new technologies are not yet fully established as part of the management of cardiac diseases but will become so in the near future. The discussion presented here reviews some of the pioneering works at this new frontier. Key results of allogeneic and autologous stem cell trials are presented, including the use of embryonic, bone marrow-derived, adipose-derived, and resident cardiac stem cells. PMID:25999743

  6. Proangiogenic scaffolds as functional templates for cardiac tissue engineering

    PubMed Central

    Madden, Lauran R.; Mortisen, Derek J.; Sussman, Eric M.; Dupras, Sarah K.; Fugate, James A.; Cuy, Janet L.; Hauch, Kip D.; Laflamme, Michael A.; Murry, Charles E.; Ratner, Buddy D.

    2010-01-01

    We demonstrate here a cardiac tissue-engineering strategy addressing multicellular organization, integration into host myocardium, and directional cues to reconstruct the functional architecture of heart muscle. Microtemplating is used to shape poly(2-hydroxyethyl methacrylate-co-methacrylic acid) hydrogel into a tissue-engineering scaffold with architectures driving heart tissue integration. The construct contains parallel channels to organize cardiomyocyte bundles, supported by micrometer-sized, spherical, interconnected pores that enhance angiogenesis while reducing scarring. Surface-modified scaffolds were seeded with human ES cell-derived cardiomyocytes and cultured in vitro. Cardiomyocytes survived and proliferated for 2 wk in scaffolds, reaching adult heart densities. Cardiac implantation of acellular scaffolds with pore diameters of 30–40 μm showed angiogenesis and reduced fibrotic response, coinciding with a shift in macrophage phenotype toward the M2 state. This work establishes a foundation for spatially controlled cardiac tissue engineering by providing discrete compartments for cardiomyocytes and stroma in a scaffold that enhances vascularization and integration while controlling the inflammatory response. PMID:20696917

  7. Electrospun biocomposite nanofibrous patch for cardiac tissue engineering.

    PubMed

    Prabhakaran, Molamma P; Kai, Dan; Ghasemi-Mobarakeh, Laleh; Ramakrishna, Seeram

    2011-10-01

    A bioengineered construct that matches the chemical, mechanical, biological properties and extracellular matrix morphology of native tissue could be suitable as a cardiac patch for supporting the heart after myocardial infarction. The potential of utilizing a composite nanofibrous scaffold of poly(dl-lactide-co-glycolide)/gelatin (PLGA/Gel) as a biomimetic cardiac patch is studied by culturing a population of cardiomyocyte containing cells on the electrospun scaffolds. The chemical characterization and mechanical properties of the electrospun PLGA and PLGA/Gel nanofibers were studied by Fourier transform infrared spectroscopy, scanning electron microscopy and tensile measurements. The biocompatibility of the scaffolds was also studied and the cardiomyocytes seeded on PLGA/Gel nanofibers were found to express the typical functional cardiac proteins such as alpha-actinin and troponin I, showing the easy integration of cardiomyocytes on PLGA/Gel scaffolds. Our studies strengthen the application of electrospun PLGA/Gel nanofibers as a bio-mechanical support for injured myocardium and as a potential substrate for induction of endogenous cardiomyocyte proliferation, ultimately reducing the cardiac dysfunction and improving cardiac remodeling. PMID:21813957

  8. Fabrication and characterization of bio-engineered cardiac pseudo tissues

    PubMed Central

    Xu, Tao; Baicu, Catalin; Aho, Michael; Zile, Michael; Boland, Thomas

    2014-01-01

    We report to fabricate functional three-dimensional (3D) tissue constructs by using an inkjet based bio-prototyping method. With the use of the modified inkjet printers, contractile cardiac hybrids that exhibit the forms of the 3D rectangular sheet and even the “half heart” (with two connected ventricles) have been fabricated by arranging alternate layers of biocompatible alginate hydrogels and mammalian cardiac cells according to pre-designed 3D patterns. In this study, primary feline adult and H1 cardiomyocytes were used as model cardiac cells. Alginate hydrogels with controlled micro-shell structures were built by spraying cross-linkers in micro drops onto un-gelled alginic acid. The cells remained viable in constructs as thick as 1 cm due to the programmed porosity. Microscopic and macroscopic contractile functions of these cardiomyocytes constructs were observed in vitro. These results suggest that the inkjet bio-prototyping method could be used for hierarchical design of functional cardiac pseudo tissues, balanced with porosity for mass transport and structural support. PMID:20811105

  9. Nuclear Morphology and Deformation in Engineered Cardiac Myocytes and Tissues

    PubMed Central

    Bray, Mark-Anthony; Adams, William J.; Geisse, Nicholas A.; Feinberg, Adam W.; Sheehy, Sean P.; Parker, Kevin Kit

    2010-01-01

    Cardiac tissue engineering requires finely-tuned manipulation of the extracellular matrix (ECM) microenvironment to optimize internal myocardial organization. The myocyte nucleus is mechanically connected to the cell membrane via cytoskeletal elements, making it a target for the cellular response to perturbation of the ECM. However, the role of ECM spatial configuration and myocyte shape on nuclear location and morphology is unknown. In this study, printed ECM proteins were used to configure the geometry of cultured neonatal rat ventricular myocytes. Engineered one- and two-dimensional tissue constructs and single-myocyte islands were assayed using live fluorescence imaging to examine nuclear position, morphology and motion as a function of the imposed ECM geometry during diastolic relaxation and systolic contraction. Image analysis showed that anisotropic tissue constructs cultured on microfabricated ECM lines possessed a high degree of nuclear alignment similar to that found in vivo; nuclei in isotropic tissues were polymorphic in shape with an apparently random orientation. Nuclear eccentricity was also increased for the anisotropic tissues, suggesting that intracellular forces deform the nucleus as the cell is spatially confined. During systole, nuclei experienced increasing spatial confinement in magnitude and direction of displacement as tissue anisotropy increased, yielding anisotropic deformation. Thus, the nature of nuclear displacement and deformation during systole appears to rely on a combination of the passive myofibril spatial organization and the active stress fields induced by contraction. Such findings have implications in understanding the genomic consequences and functional response of cardiac myocytes to their ECM surroundings under conditions of disease. PMID:20382423

  10. Conducting the embryonic heart: orchestrating development of specialized cardiac tissues.

    PubMed

    Gourdie, R G; Kubalak, S; Mikawa, T

    1999-01-01

    The heterogeneous tissues of the pacemaking and conduction system comprise the "smart components" of the heart, responsible for setting, maintaining, and coordinating the rhythmic pumping of cardiac muscle. Over the last few years, a wealth of new information has been collected about the unique genetic and phenotypic characteristics expressed by these tissues during cardiac morphogenesis. More recently, genetically modified viruses, mutational analysis, and targeted transgenesis have enabled even more precise resolution of the relationships between cell fate, gene expression, and differentiation of specialized function within developing myocardium. While some information provided by these newer approaches has supported conventional wisdom, some fresh and unexpected perspectives have also emerged. In particular, there is mounting evidence that extracardiac populations of cells migrating into the tubular heart have important morphogenetic roles in the inductive pattering and functional integration of the developing conduction system. PMID:10189963

  11. Optical control of excitation waves in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Burton, Rebecca A. B.; Klimas, Aleksandra; Ambrosi, Christina M.; Tomek, Jakub; Corbett, Alex; Entcheva, Emilia; Bub, Gil

    2015-12-01

    In nature, macroscopic excitation waves are found in a diverse range of settings including chemical reactions, metal rust, yeast, amoeba and the heart and brain. In the case of living biological tissue, the spatiotemporal patterns formed by these excitation waves are different in healthy and diseased states. Current electrical and pharmacological methods for wave modulation lack the spatiotemporal precision needed to control these patterns. Optical methods have the potential to overcome these limitations, but to date have only been demonstrated in simple systems, such as the Belousov-Zhabotinsky chemical reaction. Here, we combine dye-free optical imaging with optogenetic actuation to achieve dynamic control of cardiac excitation waves. Illumination with patterned light is demonstrated to optically control the direction, speed and spiral chirality of such waves in cardiac tissue. This all-optical approach offers a new experimental platform for the study and control of pattern formation in complex biological excitable systems.

  12. Approximate analytical solutions for excitation and propagation in cardiac tissue.

    PubMed

    Greene, D'Artagnan; Shiferaw, Yohannes

    2015-04-01

    It is well known that a variety of cardiac arrhythmias are initiated by a focal excitation in heart tissue. At the single cell level these currents are typically induced by intracellular processes such as spontaneous calcium release (SCR). However, it is not understood how the size and morphology of these focal excitations are related to the electrophysiological properties of cardiac cells. In this paper a detailed physiologically based ionic model is analyzed by projecting the excitation dynamics to a reduced one-dimensional parameter space. Based on this analysis we show that the inward current required for an excitation to occur is largely dictated by the voltage dependence of the inward rectifier potassium current (I(K1)), and is insensitive to the detailed properties of the sodium current. We derive an analytical expression relating the size of a stimulus and the critical current required to induce a propagating action potential (AP), and argue that this relationship determines the necessary number of cells that must undergo SCR in order to induce ectopic activity in cardiac tissue. Finally, we show that, once a focal excitation begins to propagate, its propagation characteristics, such as the conduction velocity and the critical radius for propagation, are largely determined by the sodium and gap junction currents with a substantially lesser effect due to repolarizing potassium currents. These results reveal the relationship between ion channel properties and important tissue scale processes such as excitation and propagation. PMID:25974539

  13. Approximate analytical solutions for excitation and propagation in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Greene, D'Artagnan; Shiferaw, Yohannes

    2015-04-01

    It is well known that a variety of cardiac arrhythmias are initiated by a focal excitation in heart tissue. At the single cell level these currents are typically induced by intracellular processes such as spontaneous calcium release (SCR). However, it is not understood how the size and morphology of these focal excitations are related to the electrophysiological properties of cardiac cells. In this paper a detailed physiologically based ionic model is analyzed by projecting the excitation dynamics to a reduced one-dimensional parameter space. Based on this analysis we show that the inward current required for an excitation to occur is largely dictated by the voltage dependence of the inward rectifier potassium current (IK 1) , and is insensitive to the detailed properties of the sodium current. We derive an analytical expression relating the size of a stimulus and the critical current required to induce a propagating action potential (AP), and argue that this relationship determines the necessary number of cells that must undergo SCR in order to induce ectopic activity in cardiac tissue. Finally, we show that, once a focal excitation begins to propagate, its propagation characteristics, such as the conduction velocity and the critical radius for propagation, are largely determined by the sodium and gap junction currents with a substantially lesser effect due to repolarizing potassium currents. These results reveal the relationship between ion channel properties and important tissue scale processes such as excitation and propagation.

  14. Highly Elastic Micropatterned Hydrogel for Engineering Functional Cardiac Tissue

    PubMed Central

    Annabi, Nasim; Tsang, Kelly; Mithieux, Suzanne M.; Nikkhah, Mehdi; Ameri, Afshin

    2013-01-01

    Heart failure is a major international health issue. Myocardial mass loss and lack of contractility are precursors to heart failure. Surgical demand for effective myocardial repair is tempered by a paucity of appropriate biological materials. These materials should conveniently replicate natural human tissue components, convey persistent elasticity, promote cell attachment, growth and conformability to direct cell orientation and functional performance. Here, microfabrication techniques are applied to recombinant human tropoelastin, the resilience-imparting protein found in all elastic human tissues, to generate photocrosslinked biological materials containing well-defined micropatterns. These highly elastic substrates are then used to engineer biomimetic cardiac tissue constructs. The micropatterned hydrogels, produced through photocrosslinking of methacrylated tropoelastin (MeTro), promote the attachment, spreading, alignment, function, and intercellular communication of cardiomyocytes by providing an elastic mechanical support that mimics their dynamic mechanical properties in vivo. The fabricated MeTro hydrogels also support the synchronous beating of cardiomyocytes in response to electrical field stimulation. These novel engineered micropatterned elastic gels are designed to be amenable to 3D modular assembly and establish a versatile, adaptable foundation for the modeling and regeneration of functional cardiac tissue with potential for application to other elastic tissues. PMID:24319406

  15. Optical Imaging of Voltage and Calcium in Cardiac Cells & Tissues

    PubMed Central

    Herron, Todd J.; Lee, Peter; Jalife, José

    2012-01-01

    Cardiac optical mapping has proven to be a powerful technology for studying cardiovascular function and disease. The development and scientific impact of this methodology are well documented. Because of its relevance in cardiac research, this imaging technology advances at a rapid pace. Here we review technological and scientific developments during the past several years and look also towards the future. First we explore key components of a modern optical mapping setup, focusing on 1) new camera technologies, 2) powerful light-emitting-diodes (from ultraviolet to red) for illumination, 3) improved optical filter technology, 4) new synthetic and optogenetic fluorescent probes, 5) optical mapping with motion and contraction, 6) new multi-parametric optical mapping techniques and 7) photon scattering effects in thick tissue preparations. We then look at recent optical mapping studies in single cells, cardiomyocyte monolayers, atria and whole hearts. Finally, we briefly look into the possible future roles of optical mapping in the development of regenerative cardiac research, cardiac cell therapies, and molecular genetic advances. PMID:22343556

  16. Engineered cardiac micromodules for the in vitro fabrication of 3D endogenous macro-tissues.

    PubMed

    Totaro, A; Urciuolo, F; Imparato, G; Netti, P A

    2016-01-01

    The in vitro fabrication of an endogenous cardiac muscle would have a high impact for both in vitro studies concerning cardiac tissue physiology and pathology, as well as in vivo application to potentially repair infarcted myocardium. To reach this aim, we engineered a new class of cardiac tissue precursor (CTP), specifically conceived in order to promote the synthesis and the assembly of a cardiac extracellular matrix (ECM). The CTPs were obtained by culturing a mixed cardiac cell population, composed of myocyte and non-myocyte cells, into porous gelatin microspheres in a dynamic bioreactor. By engineering the culture conditions, the CTP developed both beating properties and an endogenous immature cardiac ECM. By following a bottom-up approach, a macrotissue was fabricated by molding and packing the engineered tissue precursor in a maturation chamber. During the macrotissue formation, the tissue precursors acted as cardiac tissue depots by promoting the formation of an endogenous and interconnected cardiac network embedding the cells and the microbeads. The myocytes cell fraction pulled on ECM network and induced its compaction against the internal posts represented by the initial porous microbeads. This reciprocal interplay induced ECM consolidation without the use of external biophysical stimuli by leading to the formation of a beating and endogenous macrotissue. We have thus engineered a new class of cardiac micromodules and show its potential for the fabrication of endogenous cardiac tissue models useful for in vitro studies that involve the cardiac tissue remodeling. PMID:27213995

  17. Cardiac dysfunction among soft tissue sarcoma patients in Denmark

    PubMed Central

    Shantakumar, Sumitra; Olsen, Morten; Vo, Thao T; Nørgaard, Mette; Pedersen, Lars

    2016-01-01

    Purpose Soft tissue sarcoma (STS) patients may experience post-treatment cardiotoxicity, yet no population-based data exist. We examined the incidence of left ventricular ejection fraction (LVEF) decline, heart failure, and cardiac death following STS diagnosis among adults, using Danish patient registries and medical record review. Patients and methods LVEF decline was examined in a regional cohort of STS patients diagnosed during 1997–2011 in Western Denmark for whom cardiac imaging data were available. LVEF decline was defined as an absolute decline from baseline to follow-up of 10% or more, or, where baseline imaging was not available, a decline below the lower limit of normal (or 40%) for a follow-up LVEF. Heart failure and cardiac death were investigated in a national Danish cohort of all STS patients diagnosed from 2000 to 2009. We followed patients from STS diagnosis until heart failure, cardiac death, emigration or December 31, 2012 (whichever occurred first). Results The incidence rate of LVEF decline for the regional cohort with follow-up data (N=100, five events) or baseline and follow-up measurements (N=75, 19 events) was 16.8 (95% confidence interval [CI]: 7.0–40.3) and 108 (95% CI: 69–170), respectively, per 1,000 person-years. In the national cohort (N=1,187), the incidence of heart failure (40 events) and cardiac death (15 events) was 7.3 (95% CI: 5.4–10.0) and 2.7 (95% CI: 1.6–4.5), respectively, per 1,000 person-years. The strongest predictors of heart failure were doxorubicin treatment (hazard ratio [HR] =2.2, 95% CI: 0.5–10.2) and pre-existing cardiovascular disease (HR=6.3, 95% CI: 0.98–40.6). Conclusion LVEF decline occurred more frequently compared to heart failure or cardiac death in a nationally representative cohort of Danish STS patients. PMID:27186077

  18. Human progenitor cells derived from cardiac adipose tissue ameliorate myocardial infarction in rodents.

    PubMed

    Bayes-Genis, Antoni; Soler-Botija, Carolina; Farré, Jordi; Sepúlveda, Pilar; Raya, Angel; Roura, Santiago; Prat-Vidal, Cristina; Gálvez-Montón, Carolina; Montero, José Anastasio; Büscher, Dirk; Izpisúa Belmonte, Juan Carlos

    2010-11-01

    Myocardial infarction caused by vascular occlusion results in the formation of nonfunctional fibrous tissue. Cumulative evidence indicates that cell therapy modestly improves cardiac function; thus, novel cell sources with the potential to repair injured tissue are actively sought. Here, we identify and characterize a cell population of cardiac adipose tissue-derived progenitor cells (ATDPCs) from biopsies of human adult cardiac adipose tissue. Cardiac ATDPCs express a mesenchymal stem cell-like marker profile (strongly positive for CD105, CD44, CD166, CD29 and CD90) and have immunosuppressive capacity. Moreover, cardiac ATDPCs have an inherent cardiac-like phenotype and were able to express de novo myocardial and endothelial markers in vitro but not to differentiate into adipocytes. In addition, when cardiac ATDPCs were transplanted into injured myocardium in mouse and rat models of myocardial infarction, the engrafted cells expressed cardiac (troponin I, sarcomeric α-actinin) and endothelial (CD31) markers, vascularization increased, and infarct size was reduced in mice and rats. Moreover, significant differences between control and cell-treated groups were found in fractional shortening and ejection fraction, and the anterior wall remained significantly thicker 30days after cardiac delivery of ATDPCs. Finally, cardiac ATDPCs secreted proangiogenic factors under in vitro hypoxic conditions, suggesting a paracrine effect to promote local vascularization. Our results indicate that the population of progenitor cells isolated from human cardiac adipose tissue (cardiac ATDPCs) may be valid candidates for future use in cell therapy to regenerate injured myocardium. PMID:20713059

  19. Electrical Pacing of Cardiac Tissue Including Potassium Inward Rectification

    PubMed Central

    Galappaththige, Suran; Roth, Bradley J.

    2015-01-01

    In this study cardiac tissue is stimulated electrically through a small unipolar electrode. Numerical simulations predict that around an electrode are adjacent regions of depolarization and hyperpolarization. Experiments have shown that during pacing of resting cardiac tissue the hyperpolarization is often inhibited. Our goal is to determine if the inward rectifying potassium current (IK1) causes the inhibition of hyperpolarization. Numerical simulations were carried out using the bidomain model with potassium dynamics specified to be inward rectifying. In the simulations, adjacent regions of depolarization and hyperpolarization were observed surrounding the electrode. For cathodal currents the virtual anode produces a hyperpolarization that decreases over time. For long duration pulses the current-voltage curve is non-linear, with very small hyperpolarization compared to depolarization. For short pulses, the hyperpolarization is more prominent. Without the inward potassium rectification, the current voltage curve is linear and the hyperpolarization is evident for both long and short pulses. In conclusion, the inward rectification of the potassium current explains the inhibition of hyperpolarization for long duration stimulus pulses, but not for short duration pulses. PMID:26057242

  20. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function

    NASA Astrophysics Data System (ADS)

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-06-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function.

  1. Electrically Conductive Chitosan/Carbon Scaffolds for Cardiac Tissue Engineering

    PubMed Central

    2015-01-01

    In this work, carbon nanofibers were used as doping material to develop a highly conductive chitosan-based composite. Scaffolds based on chitosan only and chitosan/carbon composites were prepared by precipitation. Carbon nanofibers were homogeneously dispersed throughout the chitosan matrix, and the composite scaffold was highly porous with fully interconnected pores. Chitosan/carbon scaffolds had an elastic modulus of 28.1 ± 3.3 KPa, similar to that measured for rat myocardium, and excellent electrical properties, with a conductivity of 0.25 ± 0.09 S/m. The scaffolds were seeded with neonatal rat heart cells and cultured for up to 14 days, without electrical stimulation. After 14 days of culture, the scaffold pores throughout the construct volume were filled with cells. The metabolic activity of cells in chitosan/carbon constructs was significantly higher as compared to cells in chitosan scaffolds. The incorporation of carbon nanofibers also led to increased expression of cardiac-specific genes involved in muscle contraction and electrical coupling. This study demonstrates that the incorporation of carbon nanofibers into porous chitosan scaffolds improved the properties of cardiac tissue constructs, presumably through enhanced transmission of electrical signals between the cells. PMID:24417502

  2. Electrically conductive chitosan/carbon scaffolds for cardiac tissue engineering.

    PubMed

    Martins, Ana M; Eng, George; Caridade, Sofia G; Mano, João F; Reis, Rui L; Vunjak-Novakovic, Gordana

    2014-02-10

    In this work, carbon nanofibers were used as doping material to develop a highly conductive chitosan-based composite. Scaffolds based on chitosan only and chitosan/carbon composites were prepared by precipitation. Carbon nanofibers were homogeneously dispersed throughout the chitosan matrix, and the composite scaffold was highly porous with fully interconnected pores. Chitosan/carbon scaffolds had an elastic modulus of 28.1 ± 3.3 KPa, similar to that measured for rat myocardium, and excellent electrical properties, with a conductivity of 0.25 ± 0.09 S/m. The scaffolds were seeded with neonatal rat heart cells and cultured for up to 14 days, without electrical stimulation. After 14 days of culture, the scaffold pores throughout the construct volume were filled with cells. The metabolic activity of cells in chitosan/carbon constructs was significantly higher as compared to cells in chitosan scaffolds. The incorporation of carbon nanofibers also led to increased expression of cardiac-specific genes involved in muscle contraction and electrical coupling. This study demonstrates that the incorporation of carbon nanofibers into porous chitosan scaffolds improved the properties of cardiac tissue constructs, presumably through enhanced transmission of electrical signals between the cells. PMID:24417502

  3. Fabrication and evaluation of reconstructed cardiac tissue and its application to bio-actuated microdevices.

    PubMed

    Horiguchi, Hiroshi; Imagawa, Kentaro; Hoshino, Takayuki; Akiyama, Yoshitake; Morishima, Keisuke

    2009-12-01

    In this paper, we proposed to utilize a reconstructed cardiac tissue as microactuator with easy assembly. In a glucose solution, cardiomyocytes can contract autonomously using only chemical energy. However, a single cardiomyocyte is not enough to actuate a microrobot or a mechanical system. Though the output power will increase by using multiple cardiomyocyte, it is difficult to assemble those cardiomyocyte to predefined positions one-by-one using a micromanipulator. Reconstructed cardiac tissue not only will enable researchers to assemble the cells easily and but also has a potential to improve the contractile ability. To realize a bio-actuator in this paper, we reconstructed a microcardiac tissue using an extracellular matrix, and their displacements, displacement frequency, contractile force, and lifetime of the reconstructed cardiac tissue were evaluated. Electrical and pharmacological responses of the reconstructed cardiac tissue were also evaluated. Finally, a bioactuator, a primitive micropillar actuator, was fabricated and applicability of the reconstructed cardiac tissue for bioactuators was evaluated. PMID:20142148

  4. Curvature-dependent excitation propagation in cultured cardiac tissue

    NASA Astrophysics Data System (ADS)

    Kadota, S.; Kay, M. W.; Magome, N.; Agladze, K.

    2012-02-01

    The geometry of excitation wave front may play an important role on the propagation block and spiral wave formation. The wave front which is bent over the critical value due to interaction with the obstacles may partially cease to propagate and appearing wave breaks evolve into rotating waves or reentry. This scenario may explain how reentry spontaneously originates in a heart. We studied highly curved excitation wave fronts in the cardiac tissue culture and found that in the conditions of normal, non-inhibited excitability the curvature effects do not play essential role in the propagation. Neither narrow isthmuses nor sharp corners of the obstacles, being classical objects for production of extremely curved wave front, affect non-inhibited wave propagation. The curvature-related phenomena of the propagation block and wave detachment from the obstacle boundary were observed only after partial suppression of the sodium channels with Lidocaine. Computer simulations confirmed the experimental observations. The explanation of the observed phenomena refers to the fact that the heart tissue is made of finite size cells so that curvature radii smaller than the cardiomyocyte size loses sense, and in non-inhibited tissue the single cell is capable to transmit excitation to its neighbors.

  5. Engineered Biomaterials to Enhance Stem Cell-Based Cardiac Tissue Engineering and Therapy.

    PubMed

    Hasan, Anwarul; Waters, Renae; Roula, Boustany; Dana, Rahbani; Yara, Seif; Alexandre, Toubia; Paul, Arghya

    2016-07-01

    Cardiovascular disease is a leading cause of death worldwide. Since adult cardiac cells are limited in their proliferation, cardiac tissue with dead or damaged cardiac cells downstream of the occluded vessel does not regenerate after myocardial infarction. The cardiac tissue is then replaced with nonfunctional fibrotic scar tissue rather than new cardiac cells, which leaves the heart weak. The limited proliferation ability of host cardiac cells has motivated investigators to research the potential cardiac regenerative ability of stem cells. Considerable progress has been made in this endeavor. However, the optimum type of stem cells along with the most suitable matrix-material and cellular microenvironmental cues are yet to be identified or agreed upon. This review presents an overview of various types of biofunctional materials and biomaterial matrices, which in combination with stem cells, have shown promises for cardiac tissue replacement and reinforcement. Engineered biomaterials also have applications in cardiac tissue engineering, in which tissue constructs are developed in vitro by combining stem cells and biomaterial scaffolds for drug screening or eventual implantation. This review highlights the benefits of using biomaterials in conjunction with stem cells to repair damaged myocardium and give a brief description of the properties of these biomaterials that make them such valuable tools to the field. PMID:26953627

  6. Vascularisation to improve translational potential of tissue engineering systems for cardiac repair.

    PubMed

    Dilley, Rodney J; Morrison, Wayne A

    2014-11-01

    Cardiac tissue engineering is developing as an alternative approach to heart transplantation for treating heart failure. Shortage of organ donors and complications arising after orthotopic transplant remain major challenges to the modern field of heart transplantation. Engineering functional myocardium de novo requires an abundant source of cardiomyocytes, a biocompatible scaffold material and a functional vasculature to sustain the high metabolism of the construct. Progress has been made on several fronts, with cardiac cell biology, stem cells and biomaterials research particularly promising for cardiac tissue engineering, however currently employed strategies for vascularisation have lagged behind and limit the volume of tissue formed. Over ten years we have developed an in vivo tissue engineering model to construct vascularised tissue from various cell and tissue sources, including cardiac tissue. In this article we review the progress made with this approach and others, together with their potential to support a volume of engineered tissue for cardiac tissue engineering where contractile mass impacts directly on functional outcomes in translation to the clinic. It is clear that a scaled-up cardiac tissue engineering solution required for clinical treatment of heart failure will include a robust vascular supply for successful translation. This article is part of a directed issue entitled: Regenerative Medicine: the challenge of translation. PMID:25449260

  7. Reentry Near the Percolation Threshold in a Heterogeneous Discrete Model for Cardiac Tissue

    NASA Astrophysics Data System (ADS)

    Alonso, Sergio; Bär, Markus

    2013-04-01

    Arrhythmias in cardiac tissue are related to irregular electrical wave propagation in the heart. Cardiac tissue is formed by a discrete cell network, which is often heterogeneous. A localized region with a fraction of nonconducting links surrounded by homogeneous conducting tissue can become a source of reentry and ectopic beats. Extensive simulations in a discrete model of cardiac tissue show that a wave crossing a heterogeneous region of cardiac tissue can disintegrate into irregular patterns, provided the fraction of nonconducting links is close to the percolation threshold of the cell network. The dependence of the reentry probability on this fraction, the system size, and the degree of excitability can be inferred from the size distribution of nonconducting clusters near the percolation threshold.

  8. Coiled fiber scaffolds embedded with gold nanoparticles improve the performance of engineered cardiac tissues

    NASA Astrophysics Data System (ADS)

    Fleischer, Sharon; Shevach, Michal; Feiner, Ron; Dvir, Tal

    2014-07-01

    Coiled perimysial fibers within the heart muscle provide it with the ability to contract and relax efficiently. Here, we report on a new nanocomposite scaffold for cardiac tissue engineering, integrating coiled electrospun fibers with gold nanoparticles. Cultivation of cardiac cells within the hybrid scaffolds promoted cell organization into elongated and aligned tissues generating a strong contraction force, high contraction rate and low excitation threshold.Coiled perimysial fibers within the heart muscle provide it with the ability to contract and relax efficiently. Here, we report on a new nanocomposite scaffold for cardiac tissue engineering, integrating coiled electrospun fibers with gold nanoparticles. Cultivation of cardiac cells within the hybrid scaffolds promoted cell organization into elongated and aligned tissues generating a strong contraction force, high contraction rate and low excitation threshold. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00300d

  9. Non-Linear Dynamics of Cardiac Alternans: Subcellular to Tissue-Level Mechanisms of Arrhythmia

    PubMed Central

    Gaeta, Stephen A.; Christini, David J.

    2012-01-01

    Cardiac repolarization alternans is a rhythm disturbance of the heart in which rapid stimulation elicits a beat-to-beat alternation in the duration of action potentials and magnitude of intracellular calcium transients in individual cardiac myocytes. Although this phenomenon has been identified as a potential precursor to dangerous reentrant arrhythmias and sudden cardiac death, significant uncertainty remains regarding its mechanism and no clinically practical means of halting its occurrence or progression currently exists. Cardiac alternans has well-characterized tissue, cellular, and subcellular manifestations, the mechanisms and interplay of which are an active area of research. PMID:22783195

  10. Coiled fiber scaffolds embedded with gold nanoparticles improve the performance of engineered cardiac tissues.

    PubMed

    Fleischer, Sharon; Shevach, Michal; Feiner, Ron; Dvir, Tal

    2014-08-21

    Coiled perimysial fibers within the heart muscle provide it with the ability to contract and relax efficiently. Here, we report on a new nanocomposite scaffold for cardiac tissue engineering, integrating coiled electrospun fibers with gold nanoparticles. Cultivation of cardiac cells within the hybrid scaffolds promoted cell organization into elongated and aligned tissues generating a strong contraction force, high contraction rate and low excitation threshold. PMID:24744098

  11. The role of tissue engineering and biomaterials in cardiac regenerative medicine.

    PubMed

    Zhao, Yimu; Feric, Nicole T; Thavandiran, Nimalan; Nunes, Sara S; Radisic, Milica

    2014-11-01

    In recent years, the development of 3-dimensional engineered heart tissue (EHT) has made large strides forward because of advances in stem cell biology, materials science, prevascularization strategies, and nanotechnology. As a result, the role of tissue engineering in cardiac regenerative medicine has become multifaceted as new applications become feasible. Cardiac tissue engineering has long been established to have the potential to partially or fully restore cardiac function after cardiac injury. However, EHTs may also serve as surrogate human cardiac tissue for drug-related toxicity screening. Cardiotoxicity remains a major cause of drug withdrawal in the pharmaceutical industry. Unsafe drugs reach the market because preclinical evaluation is insufficient to weed out cardiotoxic drugs in all their forms. Bioengineering methods could provide functional and mature human myocardial tissues, ie, physiologically relevant platforms, for screening the cardiotoxic effects of pharmaceutical agents and facilitate the discovery of new therapeutic agents. Finally, advances in induced pluripotent stem cells have made patient-specific EHTs possible, which opens up the possibility of personalized medicine. Herein, we give an overview of the present state of the art in cardiac tissue engineering, the challenges to the field, and future perspectives. PMID:25442432

  12. Functional Analysis of the Engineered Cardiac Tissue Grown on Recombinant Spidroin Fiber Meshes

    PubMed Central

    Teplenin, Alexander; Krasheninnikova, Anna; Agladze, Nadezhda; Sidoruk, Konstantin; Agapova, Olga; Agapov, Igor; Bogush, Vladimir; Agladze, Konstantin

    2015-01-01

    In the present study, we examined the ability of the recombinant spidroin to serve as a substrate for the cardiac tissue engineering. For this purpose, isolated neonatal rat cardiomyocytes were seeded on the electrospun spidroin fiber matrices and cultured to form the confluent cardiac monolayers. Besides the adhesion assay and immunostaining analysis, we tested the ability of the cultured cardiomyocytes to form a functional cardiac syncytium by studying excitation propagation in the cultured tissue with the aid of optical mapping. It was demonstrated that recombinant spidroin fiber meshes are directly suitable for the adherence and growth of the cardiomyocytes without additional coating with the attachment factors, such as fibronectin. PMID:25799394

  13. Electrical stimulation of cardiac adipose tissue-derived progenitor cells modulates cell phenotype and genetic machinery.

    PubMed

    Llucià-Valldeperas, A; Sanchez, B; Soler-Botija, C; Gálvez-Montón, C; Prat-Vidal, C; Roura, S; Rosell-Ferrer, J; Bragos, R; Bayes-Genis, A

    2015-11-01

    A major challenge of cardiac tissue engineering is directing cells to establish the physiological structure and function of the myocardium being replaced. Our aim was to examine the effect of electrical stimulation on the cardiodifferentiation potential of cardiac adipose tissue-derived progenitor cells (cardiac ATDPCs). Three different electrical stimulation protocols were tested; the selected protocol consisted of 2 ms monophasic square-wave pulses of 50 mV/cm at 1 Hz over 14 days. Cardiac and subcutaneous ATDPCs were grown on biocompatible patterned surfaces. Cardiomyogenic differentiation was examined by real-time PCR and immunocytofluorescence. In cardiac ATDPCs, MEF2A and GATA-4 were significantly upregulated at day 14 after stimulation, while subcutaneous ATDPCs only exhibited increased Cx43 expression. In response to electrical stimulation, cardiac ATDPCs elongated, and both cardiac and subcutaneous ATDPCs became aligned following the linear surface pattern of the construct. Cardiac ATDPC length increased by 11.3%, while subcutaneous ATDPC length diminished by 11.2% (p = 0.013 and p = 0.030 vs unstimulated controls, respectively). Compared to controls, electrostimulated cells became aligned better to the patterned surfaces when the pattern was perpendicular to the electric field (89.71 ± 28.47º for cardiac ATDPCs and 92.15 ± 15.21º for subcutaneous ATDPCs). Electrical stimulation of cardiac ATDPCs caused changes in cell phenotype and genetic machinery, making them more suitable for cardiac regeneration approaches. Thus, it seems advisable to use electrical cell training before delivery as a cell suspension or within engineered tissue. PMID:23420554

  14. Tissue and Animal Models of Sudden Cardiac Death

    PubMed Central

    Sallam, Karim; Li, Yingxin; Sager, Philip T.; Houser, Steven R.; Wu, Joseph C.

    2015-01-01

    Sudden Cardiac Death (SCD) is a common cause of death in patients with structural heart disease, genetic mutations or acquired disorders affecting cardiac ion channels. A wide range of platforms exist to model and study disorders associated with SCD. Human clinical studies are cumbersome and are thwarted by the extent of investigation that can be performed on human subjects. Animal models are limited by their degree of homology to human cardiac electrophysiology including ion channel expression. Most commonly used cellular models are cellular transfection models, which are able to mimic the expression of a single ion channel offering incomplete insight into changes of the action potential profile. Induced pluripotent stem cell derived Cardiomyocytes (iPSC-CMs) resemble, but are not identical, to adult human cardiomyocytes, and provide a new platform for studying arrhythmic disorders leading to SCD. A variety of platforms exist to phenotype cellular models including conventional and automated patch clamp, multi-electrode array, and computational modeling. iPSC-CMs have been used to study Long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, hypertrophic cardiomyopathy and other hereditary cardiac disorders. Although iPSC-CMs are distinct from adult cardiomyocytes, they provide a robust platform to advance the science and clinical care of SCD. PMID:26044252

  15. Verification of cardiac tissue electrophysiology simulators using an N-version benchmark.

    PubMed

    Niederer, Steven A; Kerfoot, Eric; Benson, Alan P; Bernabeu, Miguel O; Bernus, Olivier; Bradley, Chris; Cherry, Elizabeth M; Clayton, Richard; Fenton, Flavio H; Garny, Alan; Heidenreich, Elvio; Land, Sander; Maleckar, Mary; Pathmanathan, Pras; Plank, Gernot; Rodríguez, José F; Roy, Ishani; Sachse, Frank B; Seemann, Gunnar; Skavhaug, Ola; Smith, Nic P

    2011-11-13

    Ongoing developments in cardiac modelling have resulted, in particular, in the development of advanced and increasingly complex computational frameworks for simulating cardiac tissue electrophysiology. The goal of these simulations is often to represent the detailed physiology and pathologies of the heart using codes that exploit the computational potential of high-performance computing architectures. These developments have rapidly progressed the simulation capacity of cardiac virtual physiological human style models; however, they have also made it increasingly challenging to verify that a given code provides a faithful representation of the purported governing equations and corresponding solution techniques. This study provides the first cardiac tissue electrophysiology simulation benchmark to allow these codes to be verified. The benchmark was successfully evaluated on 11 simulation platforms to generate a consensus gold-standard converged solution. The benchmark definition in combination with the gold-standard solution can now be used to verify new simulation codes and numerical methods in the future. PMID:21969679

  16. Verification of cardiac tissue electrophysiology simulators using an N-version benchmark

    PubMed Central

    Niederer, Steven A.; Kerfoot, Eric; Benson, Alan P.; Bernabeu, Miguel O.; Bernus, Olivier; Bradley, Chris; Cherry, Elizabeth M.; Clayton, Richard; Fenton, Flavio H.; Garny, Alan; Heidenreich, Elvio; Land, Sander; Maleckar, Mary; Pathmanathan, Pras; Plank, Gernot; Rodríguez, José F.; Roy, Ishani; Sachse, Frank B.; Seemann, Gunnar; Skavhaug, Ola; Smith, Nic P.

    2011-01-01

    Ongoing developments in cardiac modelling have resulted, in particular, in the development of advanced and increasingly complex computational frameworks for simulating cardiac tissue electrophysiology. The goal of these simulations is often to represent the detailed physiology and pathologies of the heart using codes that exploit the computational potential of high-performance computing architectures. These developments have rapidly progressed the simulation capacity of cardiac virtual physiological human style models; however, they have also made it increasingly challenging to verify that a given code provides a faithful representation of the purported governing equations and corresponding solution techniques. This study provides the first cardiac tissue electrophysiology simulation benchmark to allow these codes to be verified. The benchmark was successfully evaluated on 11 simulation platforms to generate a consensus gold-standard converged solution. The benchmark definition in combination with the gold-standard solution can now be used to verify new simulation codes and numerical methods in the future. PMID:21969679

  17. Stem Cells for Cardiac Regeneration by Cell Therapy and Myocardial Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Wu, Jun; Zeng, Faquan; Weisel, Richard D.; Li, Ren-Ke

    Congestive heart failure, which often occurs progressively following a myocardial infarction, is characterized by impaired myocardial perfusion, ventricular dilatation, and cardiac dysfunction. Novel treatments are required to reverse these effects - especially in older patients whose endogenous regenerative responses to currently available therapies are limited by age. This review explores the current state of research for two related approaches to cardiac regeneration: cell therapy and tissue engineering. First, to evaluate cell therapy, we review the effectiveness of various cell types for their ability to limit ventricular dilatation and promote functional recovery following implantation into a damaged heart. Next, to assess tissue engineering, we discuss the characteristics of several biomaterials for their potential to physically support the infarcted myocardium and promote implanted cell survival following cardiac injury. Finally, looking ahead, we present recent findings suggesting that hybrid constructs combining a biomaterial with stem and supporting cells may be the most effective approaches to cardiac regeneration.

  18. Cardiac tissue engineering, ex-vivo: design principles in biomaterials and bioreactors.

    PubMed

    Shachar, Michal; Cohen, Smadar

    2003-07-01

    Cardiac tissue engineering has emerged as a promising approach to replace or support an infarcted cardiac tissue and thus may hold a great potential to treat and save the lives of patients with heart diseases. By its broad definition, tissue engineering involves the construction of tissue equivalents from donor cells seeded within 3-D biomaterials, then culturing and implanting the cell-seeded scaffolds to induce and direct the growth of new, healthy tissue. In this review, we present an up-to-date summary of the research in cardiac tissue engineering, with an emphasis on the design principles and selection criteria that have been used in two key technologies employed in tissue engineering, (1) biomaterials technology, for the creation of 3-D porous scaffolds which are used to support and guide the tissue formation from dissociated cells, and (2) bioreactor cultivation of the 3-D cell constructs during ex-vivo tissue engineering, which aims to duplicate the normal stresses and flows experienced by the tissues. PMID:12878836

  19. Controlling spiral waves and turbulent states in cardiac tissue by traveling wave perturbations

    NASA Astrophysics Data System (ADS)

    Wang, Peng-Ye; Xie, Ping

    2000-03-01

    We propose a traveling wave perturbation method to control the spatiotemporal dynamics in cardiac tissue. With a two-variable model we demonstrate that the method can successfully suppress the wave instability (alternans in action potential duration) in the one-dimensional case and convert spiral waves and turbulent states to the normal traveling wave state in the two-dimensional case. An experimental scheme is suggested which may provide a new design for a cardiac defibrillator.

  20. Analyzing Remodeling of Cardiac Tissue: A Comprehensive Approach Based on Confocal Microscopy and 3D Reconstructions.

    PubMed

    Seidel, Thomas; Edelmann, J-C; Sachse, Frank B

    2016-05-01

    Microstructural characterization of cardiac tissue and its remodeling in disease is a crucial step in many basic research projects. We present a comprehensive approach for three-dimensional characterization of cardiac tissue at the submicrometer scale. We developed a compression-free mounting method as well as labeling and imaging protocols that facilitate acquisition of three-dimensional image stacks with scanning confocal microscopy. We evaluated the approach with normal and infarcted ventricular tissue. We used the acquired image stacks for segmentation, quantitative analysis and visualization of important tissue components. In contrast to conventional mounting, compression-free mounting preserved cell shapes, capillary lumens and extracellular laminas. Furthermore, the new approach and imaging protocols resulted in high signal-to-noise ratios at depths up to 60 µm. This allowed extensive analyzes revealing major differences in volume fractions and distribution of cardiomyocytes, blood vessels, fibroblasts, myofibroblasts and extracellular space in control vs. infarct border zone. Our results show that the developed approach yields comprehensive data on microstructure of cardiac tissue and its remodeling in disease. In contrast to other approaches, it allows quantitative assessment of all major tissue components. Furthermore, we suggest that the approach will provide important data for physiological models of cardiac tissue at the submicrometer scale. PMID:26399990

  1. Induced Pluripotent Stem Cell-Derived Cardiac Progenitors Differentiate to Cardiomyocytes and Form Biosynthetic Tissues

    PubMed Central

    Chakraborty, Syandan; Chellapan, Malathi; Bursac, Nenad; Leong, Kam W.

    2013-01-01

    The mammalian heart has little capacity to regenerate, and following injury the myocardium is replaced by non-contractile scar tissue. Consequently, increased wall stress and workload on the remaining myocardium leads to chamber dilation, dysfunction, and heart failure. Cell-based therapy with an autologous, epigenetically reprogrammed, and cardiac-committed progenitor cell source could potentially reverse this process by replacing the damaged myocardium with functional tissue. However, it is unclear whether cardiac progenitor cell-derived cardiomyocytes are capable of attaining levels of structural and functional maturity comparable to that of terminally-fated cardiomyocytes. Here, we first describe the derivation of mouse induced pluripotent stem (iPS) cells, which once differentiated allow for the enrichment of Nkx2-5(+) cardiac progenitors, and the cardiomyocyte-specific expression of the red fluorescent protein. We show that the cardiac progenitors are multipotent and capable of differentiating into endothelial cells, smooth muscle cells and cardiomyocytes. Moreover, cardiac progenitor selection corresponds to cKit(+) cell enrichment, while cardiomyocyte cell-lineage commitment is concomitant with dual expression of either cKit/Flk1 or cKit/Sca-1. We proceed to show that the cardiac progenitor-derived cardiomyocytes are capable of forming electrically and mechanically coupled large-scale 2D cell cultures with mature electrophysiological properties. Finally, we examine the cell progenitors’ ability to form electromechanically coherent macroscopic tissues, using a physiologically relevant 3D culture model and demonstrate that following long-term culture the cardiomyocytes align, and form robust electromechanical connections throughout the volume of the biosynthetic tissue construct. We conclude that the iPS cell-derived cardiac progenitors are a robust cell source for tissue engineering applications and a 3D culture platform for pharmacological screening and

  2. Manual hematoxylin and eosin staining of mouse tissue sections.

    PubMed

    Cardiff, Robert D; Miller, Claramae H; Munn, Robert J

    2014-06-01

    The hematoxylin and eosin (H&E) stain is the standard used for microscopic examination of tissues that have been fixed, processed, embedded, and sectioned. It can be performed manually or by automation. For economic reasons, the manual technique is generally the method of choice for facilities with a low sample volume. This protocol describes manual H&E staining of fixed, processed, paraffin-embedded, and sectioned mouse tissues. In H&E-stained tissues, the nucleic acids stain dark blue and the proteins stain red to pink or orange. For accurate phenotyping and delineation of tissue detail, the protocol must be adhered to rigorously. This includes frequent reagent changes as well as the use of "in-date" reagents. Appropriate color in a good H&E stain allows for identification of many tissue subtleties that are necessary for accurate diagnosis. PMID:24890205

  3. Sectioning and imaging hard mineral fibres in biological tissues.

    PubMed

    Johnson, N F; Ibe, K

    1981-04-01

    A technique is described which overcomes the problems associated with sectioning biological tissue containing hard mineral fibres. 0.2--0.5 micrometer thick sections were cut with a diamond knife, placed in a folding grid, conventionally stained with uranyl acetate and lead citrate and viewed at an accelerating voltage of 200 kV in the scanning transmission mode. PMID:6163862

  4. Effect of Cardiac Tissue Anisotropy on Three-Dimensional Electrical Action Potential Propagation

    NASA Astrophysics Data System (ADS)

    He, Zhi Zhu; Liu, Jing

    A three-dimensional (3D) electrical action potential propagation model is developed to characterize the integrated effect of cardiac tissue structure using a homogenous function with a spatial inhomogeneity. This method may be more effective for bridging the gap between computational models and experimental data for cardiac tissue anisotropy. A generalized 3D eikonal relation considering anisotropy and a self-similar evolution solution of such a relation are derived to identify the effect of anisotropy and predict the anisotropy-induced electrical wave propagation instabilities. Furthermore, the phase field equation is introduced to obtain the complex three-dimensional numerical solution of the new correlation. The present results are expected to be valuable for better understanding the physiological behavior of cardiac tissues.

  5. Reentrant excitation in an analog-digital hybrid circuit model of cardiac tissue

    NASA Astrophysics Data System (ADS)

    Mahmud, Farhanahani; Shiozawa, Naruhiro; Makikawa, Masaaki; Nomura, Taishin

    2011-06-01

    We propose an analog-digital hybrid circuit model of one-dimensional cardiac tissue with hardware implementation that allows us to perform real-time simulations of spatially conducting cardiac action potentials. Each active nodal compartment of the tissue model is designed using analog circuits and a dsPIC microcontroller, by which the time-dependent and time-independent nonlinear current-voltage relationships of six types of ion channel currents employed in the Luo-Rudy phase I (LR-I) model for a single mammalian cardiac ventricular cell can be reproduced quantitatively. Here, we perform real-time simulations of reentrant excitation conduction in a ring-shaped tissue model that includes eighty nodal compartments. In particular, we show that the hybrid tissue model can exhibit real-time dynamics for initiation of reentries induced by uni-directional block, as well as those for phase resetting that leads to annihilation of the reentry in response to impulsive current stimulations at appropriate nodes and timings. The dynamics of the hybrid model are comparable to those of a spatially distributed tissue model with LR-I compartments. Thus, it is conceivable that the hybrid model might be a useful tool for large scale simulations of cardiac tissue dynamics, as an alternative to numerical simulations, leading toward further understanding of the reentrant mechanisms.

  6. Reduced Graphene Oxide-GelMA Hybrid Hydrogels as Scaffolds for Cardiac Tissue Engineering.

    PubMed

    Shin, Su Ryon; Zihlmann, Claudio; Akbari, Mohsen; Assawes, Pribpandao; Cheung, Louis; Zhang, Kaizhen; Manoharan, Vijayan; Zhang, Yu Shrike; Yüksekkaya, Mehmet; Wan, Kai-Tak; Nikkhah, Mehdi; Dokmeci, Mehmet R; Tang, Xiaowu Shirley; Khademhosseini, Ali

    2016-07-01

    Biomaterials currently used in cardiac tissue engineering have certain limitations, such as lack of electrical conductivity and appropriate mechanical properties, which are two parameters playing a key role in regulating cardiac cell behavior. Here, the myocardial tissue constructs are engineered based on reduced graphene oxide (rGO)-incorporated gelatin methacryloyl (GelMA) hybrid hydrogels. The incorporation of rGO into the GelMA matrix significantly enhances the electrical conductivity and mechanical properties of the material. Moreover, cells cultured on composite rGO-GelMA scaffolds exhibit better biological activities such as cell viability, proliferation, and maturation compared to ones cultured on GelMA hydrogels. Cardiomyocytes show stronger contractility and faster spontaneous beating rate on rGO-GelMA hydrogel sheets compared to those on pristine GelMA hydrogels, as well as GO-GelMA hydrogel sheets with similar mechanical property and particle concentration. Our strategy of integrating rGO within a biocompatible hydrogel is expected to be broadly applicable for future biomaterial designs to improve tissue engineering outcomes. The engineered cardiac tissue constructs using rGO incorporated hybrid hydrogels can potentially provide high-fidelity tissue models for drug studies and the investigations of cardiac tissue development and/or disease processes in vitro. PMID:27254107

  7. Age-related changes in tissue macrophages precede cardiac functional impairment.

    PubMed

    Pinto, Alexander R; Godwin, James W; Chandran, Anjana; Hersey, Lucy; Ilinykh, Alexei; Debuque, Ryan; Wang, Lina; Rosenthal, Nadia A

    2014-05-01

    Cardiac tissue macrophages (cTMs) are abundant in the murine heart but the extent to which the cTM phenotype changes with age is unknown. This study characterizes aging-dependent phenotypic changes in cTM subsets. Using theCx3cr1(GFP/+) mouse reporter line where GFP marks cTMs, and the tissue macrophage marker Mrc1, we show that two major cardiac tissue macrophage subsets, Mrc1-GFP(hi) and Mrc1+GFP(hi) cTMs, are present in the young (<10 week old) mouse heart, and a third subset, Mrc1+GFP(lo), comprises ~50% of total Mrc1+ cTMs from 30 weeks of age. Immunostaining and functional assays show that Mrc1+ cTMs are the principal myeloid sentinels in the mouse heart and that they retain proliferative capacity throughout life. Gene expression profiles of the two Mrc1+ subsets also reveal that Mrc1+GFP(lo) cTMs have a decreased number of immune response genes (Cx3cr1, Lpar6, CD9, Cxcr4, Itga6 and Tgfβr1), and an increased number of fibrogenic genes (Ltc4s, Retnla, Fgfr1, Mmp9 and Ccl24), consistent with a potential role for cTMs in cardiac fibrosis. These findings identify early age-dependent gene expression changes in cTMs, with significant implications for cardiac tissue injury responses and aging-associated cardiac fibrosis. PMID:24861132

  8. Automatic segmentation of histological structures in mammary gland tissue sections

    SciTech Connect

    Fernandez-Gonzalez, Rodrigo; Deschamps, Thomas; Idica, Adam K.; Malladi, Ravikanth; Ortiz de Solorzano, Carlos

    2004-02-17

    Real-time three-dimensional (3D) reconstruction of epithelial structures in human mammary gland tissue blocks mapped with selected markers would be an extremely helpful tool for breast cancer diagnosis and treatment planning. Besides its clear clinical application, this tool could also shed a great deal of light on the molecular basis of breast cancer initiation and progression. In this paper we present a framework for real-time segmentation of epithelial structures in two-dimensional (2D) images of sections of normal and neoplastic mammary gland tissue blocks. Complete 3D rendering of the tissue can then be done by surface rendering of the structures detected in consecutive sections of the blocks. Paraffin embedded or frozen tissue blocks are first sliced, and sections are stained with Hematoxylin and Eosin. The sections are then imaged using conventional bright field microscopy and their background is corrected using a phantom image. We then use the Fast-Marching algorithm to roughly extract the contours of the different morphological structures in the images. The result is then refined with the Level-Set method which converges to an accurate (sub-pixel) solution for the segmentation problem. Finally, our system stacks together the 2D results obtained in order to reconstruct a 3D representation of the entire tissue block under study. Our method is illustrated with results from the segmentation of human and mouse mammary gland tissue samples.

  9. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function.

    PubMed

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-06-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function. PMID:26974408

  10. [The morphological changes in the myocardial tissue after sudden cardiac death from alcoholic cardiomyopathy].

    PubMed

    Sokolova, O V

    2016-01-01

    This paper was designed to report the results of the retrospective analysis of the protocols of 180 forensic medical autopsy sections stored in the archives of Sankt-Petersburg Bureau of Forensic Medical Expertise and the data of the histological studies of myocardial tissues obtained after sudden cardiac death from alcoholic cardiomyopathy. The study revealed the following most pathognomonic histological criteria for alcoholic heart lesions: the alternation of hypertrophic and atrophic cardiomyocytes in the state of severe parenchymatous degeneration, pronounced mesenchymal fatty dystrophy in combination with pathological changes of the vascular walls (vascular wall plasmatization), sub-endothelial accumulation of the PAS-positive tissue compounds, microcirculatory disorders in the form of erythrocyte stasis with the manifestations of the blood "sludge" phenomenon, and precapillary fibrosis. The signs of severe parenchymatous and stromal vascular dystrophy of the myocardial histohematic barrier (HHB) are supposed to reflect the toxic effects of ethanol and its metabolites that are directly involved in the mechanisms underlying the disturbances of intracellular metabolism and dyscirculatory events leading to the development of heart muscle hypoxia. PMID:27030089

  11. PGS:Gelatin nanofibrous scaffolds with tunable mechanical and structural properties for engineering cardiac tissues.

    PubMed

    Kharaziha, Mahshid; Nikkhah, Mehdi; Shin, Su-Ryon; Annabi, Nasim; Masoumi, Nafiseh; Gaharwar, Akhilesh K; Camci-Unal, Gulden; Khademhosseini, Ali

    2013-09-01

    A significant challenge in cardiac tissue engineering is the development of biomimetic grafts that can potentially promote myocardial repair and regeneration. A number of approaches have used engineered scaffolds to mimic the architecture of the native myocardium tissue and precisely regulate cardiac cell functions. However, previous attempts have not been able to simultaneously recapitulate chemical, mechanical, and structural properties of the myocardial extracellular matrix (ECM). In this study, we utilized an electrospinning approach to fabricate elastomeric biodegradable poly(glycerol sebacate) (PGS):gelatin nanofibrous scaffolds with a wide range of chemical composition, stiffness and anisotropy. Our findings demonstrated that through incorporation of PGS, it is possible to create nanofibrous scaffolds with well-defined anisotropy that mimic the left ventricular myocardium architecture. Furthermore, we studied attachment, proliferation, differentiation and alignment of neonatal rat cardiac fibroblast cells (CFs) as well as protein expression, alignment, and contractile function of cardiomyocyte (CMs) on PGS:gelatin scaffolds with variable amount of PGS. Notably, aligned nanofibrous scaffold, consisting of 33 wt. % PGS, induced optimal synchronous contractions of CMs while significantly enhanced cellular alignment. Overall, our study suggests that the aligned nanofibrous PGS:gelatin scaffold support cardiac cell organization, phenotype and contraction and could potentially be used to develop clinically relevant constructs for cardiac tissue engineering. PMID:23747008

  12. PGS:Gelatin Nanofibrous Scaffolds with Tunable Mechanical and Structural Properties for Engineering Cardiac Tissues

    PubMed Central

    Kharaziha, Mahshid; Nikkhah, Mehdi; Shin, Su-Ryon; Annabi, Nasim; Masoumi, Nafiseh; Gaharwar, Akhilesh K.; Camci-Unal, Gulden; Khademhosseini, Ali

    2013-01-01

    A significant challenge in cardiac tissue engineering is the development of biomimetic grafts that can potentially promote myocardial repair and regeneration. A number of approaches have used engineered scaffolds to mimic the architecture of the native myocardium tissue and precisely regulate cardiac cell functions. However previous attempts have not been able to simultaneously recapitulate chemical, mechanical, and structural properties of the myocardial extracellular matrix (ECM). In this study, we utilized an electrospinning approach to fabricate elastomeric biodegradable poly(glycerol-sebacate) (PGS):gelatin scaffolds with a wide range of chemical composition, stiffness and anisotropy. Our findings demonstrated that through incorporation of PGS, it is possible to create nanofibrous scaffolds with well-defined anisotropy that mimics the left ventricular myocardium architecture. Furthermore, we studied attachment, proliferation, differentiation and alignment of neonatal rat cardiac fibroblast cells (CFs) as well as protein expression, alignment, and contractile function of cardiomyocyte (CMs) on PGS:gelatin scaffolds with variable amount of PGS. Notably, aligned nanofibrous scaffold, consisting of 33 wt. % PGS, induced optimal synchronous contractions of CMs while significantly enhanced cellular alignment. Overall, our study suggests that the aligned nanofibrous PGS:gelatin scaffold support cardiac cell organization, phenotype and contraction and could potentially be used to develop clinically relevant constructs for cardiac tissue engineering. PMID:23747008

  13. Infrared microspectroscopic imaging of benign breast tumor tissue sections

    NASA Astrophysics Data System (ADS)

    Fabian, H.; Lasch, P.; Boese, M.; Haensch, W.

    2003-12-01

    We have applied infrared microspectroscopic imaging for the examination of benign breast tumor tissue sections. The IR spectra of the sections were obtained by classical point microscopy with a movable stage and via a microscope equipped with a focal plane array detector. The infrared microscopic data were analysed using functional group mapping techniques and cluster analysis. The output values of the two procedures were reassembled into infrared images of the tissues, and were compared with standard staining images of the corresponding tissue region. The comparative examination of identical tissue sections by the two IR approaches enabled us to assess potential problems associated with tissue microheterogeneity. It was found that in case of fibroadenoma, a benign lesion located in breast ducts, point microscopy with a spot size of ˜30 μm is a useful practical approach which minimizes the possibility of 'contamination' of the spectra because of spectral averaging of all tissue components present in the corresponding microareas. A comparison of the spectra of the benign breast tumor with those of a malignant ductal carcinoma in situ revealed that IR microspectroscopy has the potential to differentiate between these two breast tumor types.

  14. Virtual electrodes in cardiac tissue: a common mechanism for anodal and cathodal stimulation.

    PubMed Central

    Wikswo, J P; Lin, S F; Abbas, R A

    1995-01-01

    Traditional cable analyses cannot explain complex patterns of excitation in cardiac tissue with unipolar, extracellular anodal, or cathodal stimuli. Epifluorescence imaging of the transmembrane potential during and after stimulation of both refractory and excitable tissue shows distinctive regions of simultaneous depolarization and hyperpolarization during stimulation that act as virtual cathodes and anodes. The results confirm bidomain model predictions that the onset (make) of a stimulus induces propagation from the virtual cathode, whereas stimulus termination (break) induces it from the virtual anode. In make stimulation, the virtual anode can delay activation of the underlying tissue, whereas in break stimulation this occurs under the virtual cathode. Thus make and break stimulations in cardiac tissue have a common mechanism that is the result of differences in the electrical anisotropy of the intracellular and extracellular spaces and provides clear proof of the validity of the bidomain model. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 PMID:8599628

  15. Real time assessment of RF cardiac tissue ablation with optical spectroscopy

    SciTech Connect

    Demos, S G; Sharareh, S

    2008-03-20

    An optical spectroscopy approach is demonstrated allowing for critical parameters during RF ablation of cardiac tissue to be evaluated in real time. The method is based on incorporating in a typical ablation catheter transmitting and receiving fibers that terminate at the tip of the catheter. By analyzing the spectral characteristics of the NIR diffusely reflected light, information is obtained on such parameters as, catheter-tissue proximity, lesion formation, depth of penetration of the lesion, formation of char during the ablation, formation of coagulum around the ablation site, differentiation of ablated from healthy tissue, and recognition of micro-bubble formation in the tissue.

  16. Evaluation of optical imaging and spectroscopy approaches for cardiac tissue depth assessment

    SciTech Connect

    Lin, B; Matthews, D; Chernomordik, V; Gandjbakhche, A; Lane, S; Demos, S G

    2008-02-13

    NIR light scattering from ex vivo porcine cardiac tissue was investigated to understand how imaging or point measurement approaches may assist development of methods for tissue depth assessment. Our results indicate an increase of average image intensity as thickness increases up to approximately 2 mm. In a dual fiber spectroscopy configuration, sensitivity up to approximately 3 mm with an increase to 6 mm when spectral ratio between selected wavelengths was obtained. Preliminary Monte Carlo results provided reasonable fit to the experimental data.

  17. Biomimetic scaffold combined with electrical stimulation and growth factor promotes tissue engineered cardiac development.

    PubMed

    Park, Hyoungshin; Larson, Benjamin L; Kolewe, Martin E; Vunjak-Novakovic, Gordana; Freed, Lisa E

    2014-02-15

    Toward developing biologically sound models for the study of heart regeneration and disease, we cultured heart cells on a biodegradable, microfabricated poly(glycerol sebacate) (PGS) scaffold designed with micro-structural features and anisotropic mechanical properties to promote cardiac-like tissue architecture. Using this biomimetic system, we studied individual and combined effects of supplemental insulin-like growth factor-1 (IGF-1) and electrical stimulation (ES). On culture day 8, all tissue constructs could be paced and expressed the cardiac protein troponin-T. IGF-1 reduced apoptosis, promoted cell-to-cell connectivity, and lowered excitation threshold, an index of electrophysiological activity. ES promoted formation of tissue-like bundles oriented in parallel to the electrical field and a more than ten-fold increase in matrix metalloprotease-2 (MMP-2) gene expression. The combination of IGF-1 and ES increased 2D projection length, an index of overall contraction strength, and enhanced expression of the gap junction protein connexin-43 and sarcomere development. This culture environment, designed to combine cardiac-like scaffold architecture and biomechanics with molecular and biophysical signals, enabled functional assembly of engineered heart muscle from dissociated cells and could serve as a template for future studies on the hierarchy of various signaling domains relative to cardiac tissue development. PMID:24240126

  18. Portable bioreactor for perfusion and electrical stimulation of engineered cardiac tissue

    PubMed Central

    Tandon, Nina; Taubman, Alanna; Cimetta, Elisa; Saccenti, Laetitia; Vunjak-Novakovic, Gordana

    2015-01-01

    Cardiac tissue engineering aims to create functional tissue constructs that can reestablish the structure and function of injured myocardium. Although bioreactors have facilitated the engineering of cardiac patches of clinically relevant size in vitro, a major drawback remains the transportation of the engineered tissues from a production facility to a medical operation facility while maintaining tissue viability and preventing contamination. Furthermore, after implantation, most of the cells are endangered by hypoxic conditions that exist before vascular flow is established. We developed a portable device that provides the perfusion and electrical stimulation necessary to engineer cardiac tissue in vitro, and to transport it to the site where it will be implantated. The micropump-powered perfusion apparatus may additionally function as an extracorporeal active pumping system providing nutrients and oxygen supply to the graft post-implantation. Such a system, through perfusion of oxygenated media and bioactive molecules (e.g. growth factors), could transiently support the tissue construct until it connects to the host vasculature and heart muscle, after which it could be taken away or let biodegrade. PMID:24111161

  19. Raman molecular imaging of brain frozen tissue sections.

    PubMed

    Kast, Rachel E; Auner, Gregory W; Rosenblum, Mark L; Mikkelsen, Tom; Yurgelevic, Sally M; Raghunathan, Aditya; Poisson, Laila M; Kalkanis, Steven N

    2014-10-01

    Raman spectroscopy provides a molecular signature of the region being studied. It is ideal for neurosurgical applications because it is non-destructive, label-free, not impacted by water concentration, and can map an entire region of tissue. The objective of this paper is to demonstrate the meaningful spatial molecular information provided by Raman spectroscopy for identification of regions of normal brain, necrosis, diffusely infiltrating glioma and solid glioblastoma (GBM). Five frozen section tissues (1 normal, 1 necrotic, 1 GBM, and 2 infiltrating glioma) were mapped in their entirety using a 300-µm-square step size. Smaller regions of interest were also mapped using a 25-µm step size. The relative concentrations of relevant biomolecules were mapped across all tissues and compared with adjacent hematoxylin and eosin-stained sections, allowing identification of normal, GBM, and necrotic regions. Raman peaks and peak ratios mapped included 1003, 1313, 1431, 1585, and 1659 cm(-1). Tissue maps identified boundaries of grey and white matter, necrosis, GBM, and infiltrating tumor. Complementary information, including relative concentration of lipids, protein, nucleic acid, and hemoglobin, was presented in a manner which can be easily adapted for in vivo tissue mapping. Raman spectroscopy can successfully provide label-free imaging of tissue characteristics with high accuracy. It can be translated to a surgical or laboratory tool for rapid, non-destructive imaging of tumor margins. PMID:25038847

  20. Out-of-Hospital Perimortem Cesarean Section as Resuscitative Hysterotomy in Maternal Posttraumatic Cardiac Arrest

    PubMed Central

    Gatti, Francesca; Zerbi, Simone Maria; Colombo, Dario; Landriscina, Mario; Kette, Fulvio

    2014-01-01

    The optimal treatment of a severe hemodynamic instability from shock to cardiac arrest in late term pregnant women is subject to ongoing studies. However, there is an increasing evidence that early “separation” between the mother and the foetus may increase the restoration of the hemodynamic status and, in the cardiac arrest setting, it may raise the likelihood of a return of spontaneous circulation (ROSC) in the mother. This treatment, called Perimortem Cesarean Section (PMCS), is now termed as Resuscitative Hysterotomy (RH) to better address the issue of an early Cesarean section (C-section). This strategy is in contrast with the traditional treatment of cardiac arrest characterized by the maintenance of cardiopulmonary resuscitation (CPR) maneuvers without any emergent surgical intervention. We report the case of a prehospital perimortem delivery by Caesarean (C) section of a foetus at 36 weeks of gestation after the mother's traumatic cardiac arrest. Despite the negative outcome of the mother, the choice of performing a RH seems to represent up to date the most appropriate intervention to improve the outcome in both mother and foetus. PMID:25530891

  1. Two-photon induced collagen cross-linking in bioartificial cardiac tissue

    NASA Astrophysics Data System (ADS)

    Kuetemeyer, Kai; Kensah, George; Heidrich, Marko; Meyer, Heiko; Martin, Ulrich; Gruh, Ina; Heisterkamp, Alexander

    2011-08-01

    Cardiac tissue engineering is a promising strategy for regenerative therapies to overcome the shortage of donor organs for transplantation. Besides contractile function, the stiffness of tissue engineered constructs is crucial to generate transplantable tissue surrogates with sufficient mechanical stability to withstand the high pressure present in the heart. Although several collagen cross-linking techniques have proven to be efficient in stabilizing biomaterials, they cannot be applied to cardiac tissue engineering, as cell death occurs in the treated area. Here, we present a novel method using femtosecond (fs) laser pulses to increase the stiffness of collagen-based tissue constructs without impairing cell viability. Raster scanning of the fs laser beam over riboflavin-treated tissue induced collagen cross-linking by two-photon photosensitized singlet oxygen production. One day post-irradiation, stress-strain measurements revealed increased tissue stiffness by around 40% being dependent on the fibroblast content in the tissue. At the same time, cells remained viable and fully functional as demonstrated by fluorescence imaging of cardiomyocyte mitochondrial activity and preservation of active contraction force. Our results indicate that two-photon induced collagen cross-linking has great potential for studying and improving artificially engineered tissue for regenerative therapies.

  2. Nanoscale cues regulate the structure and function of macroscopic cardiac tissue constructs

    PubMed Central

    Kim, Deok-Ho; Lipke, Elizabeth A.; Kim, Pilnam; Cheong, Raymond; Thompson, Susan; Delannoy, Michael; Suh, Kahp-Yang; Tung, Leslie; Levchenko, Andre

    2010-01-01

    Heart tissue possesses complex structural organization on multiple scales, from macro- to nano-, but nanoscale control of cardiac function has not been extensively analyzed. Inspired by ultrastructural analysis of the native tissue, we constructed a scalable, nanotopographically controlled model of myocardium mimicking the in vivo ventricular organization. Guided by nanoscale mechanical cues provided by the underlying hydrogel, the tissue constructs displayed anisotropic action potential propagation and contractility characteristic of the native tissue. Surprisingly, cell geometry, action potential conduction velocity, and the expression of a cell–cell coupling protein were exquisitely sensitive to differences in the substratum nanoscale features of the surrounding extracellular matrix. We propose that controlling cell–material interactions on the nanoscale can stipulate structure and function on the tissue level and yield novel insights into in vivo tissue physiology, while providing materials for tissue repair. PMID:20018748

  3. The Transfer Functions of Cardiac Tissue during Stochastic Pacing

    PubMed Central

    de Lange, Enno; Kucera, Jan P.

    2009-01-01

    Abstract The restitution properties of cardiac action potential duration (APD) and conduction velocity (CV) are important factors in arrhythmogenesis. They determine alternans, wavebreak, and the patterns of reentrant arrhythmias. We developed a novel approach to characterize restitution using transfer functions. Transfer functions relate an input and an output quantity in terms of gain and phase shift in the complex frequency domain. We derived an analytical expression for the transfer function of interbeat intervals (IBIs) during conduction from one site (input) to another site downstream (output). Transfer functions can be efficiently obtained using a stochastic pacing protocol. Using simulations of conduction and extracellular mapping of strands of neonatal rat ventricular myocytes, we show that transfer functions permit the quantification of APD and CV restitution slopes when it is difficult to measure APD directly. We find that the normally positive CV restitution slope attenuates IBI variations. In contrast, a negative CV restitution slope (induced by decreasing extracellular [K+]) amplifies IBI variations with a maximum at the frequency of alternans. Hence, it potentiates alternans and renders conduction unstable, even in the absence of APD restitution. Thus, stochastic pacing and transfer function analysis represent a powerful strategy to evaluate restitution and the stability of conduction. PMID:19134481

  4. Optimizing a spontaneously contracting heart tissue patch with rat neonatal cardiac cells on fibrin gel

    PubMed Central

    Tao, Ze-Wei; Mohamed, Mohamed; Hogan, Matthew; Gutierrez, Laura; Birla, Ravi K.

    2014-01-01

    Engineered cardiac tissues have been constructed with primary or stem cell-derived cardiac cells on natural or synthetic scaffolds. They represent a tremendous potential for treatment of injured areas through addition of tensional support and delivery of sufficient cells. In this study 1 to 6 million (M) neonatal cardiac cells were seeded on fibrin gels to fabricate cardiac tissue patches, and the effects of culture time and cell density on spontaneous contraction rates, twitch forces and paced response frequencies were measured. Electrocardiograms and signal volume index of connexin 43 were also analyzed. Patches of 1–6M cell densities exhibited maximal contraction rates between 305–410 bpm within the first 4 days after plating; low cell densities (1–3M) patches sustained rhythmic contraction longer than high cell densities (4–6M). Patches with 1–6 M cell densities generated contractile forces in the range 2.245–14.065 mN/mm3 on days 4–6. Upon patch formation, a paced response frequency of approximately 6 Hz was obtained, and decreased to approximately 3 Hz after 6 days of culture. High cell density patches contained a thicker real cardiac tissue layer which generated higher R wave amplitudes; however, low density patches had a greater signal volume index of connexin 43. In addition, all patches manifested endothelial cell growth and robust nuclear division. The present study demonstrates that the proper time for in vivo implantation of this cardiac construct is just at patch formation and patches with 3–4M cell densities are the best candidates. PMID:24771636

  5. TRPV-1-mediated elimination of residual iPS cells in bioengineered cardiac cell sheet tissues

    PubMed Central

    Matsuura, Katsuhisa; Seta, Hiroyoshi; Haraguchi, Yuji; Alsayegh, Khaled; Sekine, Hidekazu; Shimizu, Tatsuya; Hagiwara, Nobuhisa; Yamazaki, Kenji; Okano, Teruo

    2016-01-01

    The development of a suitable strategy for eliminating remaining undifferentiated cells is indispensable for the use of human-induced pluripotent stem (iPS) cell-derived cells in regenerative medicine. Here, we show for the first time that TRPV-1 activation through transient culture at 42 °C in combination with agonists is a simple and useful strategy to eliminate iPS cells from bioengineered cardiac cell sheet tissues. When human iPS cells were cultured at 42 °C, almost all cells disappeared by 48 hours through apoptosis. However, iPS cell-derived cardiomyocytes and fibroblasts maintained transcriptional and protein expression levels, and cardiac cell sheets were fabricated after reducing the temperature. TRPV-1 expression in iPS cells was upregulated at 42 °C, and iPS cell death at 42 °C was TRPV-1-dependent. Furthermore, TRPV-1 activation through thermal or agonist treatment eliminated iPS cells in cardiac tissues for a final concentration of 0.4% iPS cell contamination. These findings suggest that the difference in tolerance to TRPV-1 activation between iPS cells and iPS cell-derived cardiac cells could be exploited to eliminate remaining iPS cells in bioengineered cell sheet tissues, which will further reduce the risk of tumour formation. PMID:26888607

  6. From Cardiac Tissue Engineering to Heart-on-a-Chip: Beating Challenges

    PubMed Central

    Zhang, Yu Shrike; Aleman, Julio; Arneri, Andrea; Bersini, Simone; Piraino, Francesco; Shin, Su Ryon; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

    2015-01-01

    The heart is one of the most vital organs in the human body, which actively pumps the blood through the vascular network to supply nutrients to as well as to extract wastes from all other organs, maintaining the homeostasis of the biological system. Over the past few decades, tremendous efforts have been exerted in engineering functional cardiac tissues for heart regeneration via biomimetic approaches. More recently, progresses have been achieved towards the transformation of knowledge obtained from cardiac tissue engineering to building physiologically relevant microfluidic human heart models (i.e. heart-on-chips) for applications in drug discovery. The advancement in the stem cell technologies further provides the opportunity to create personalized in vitro models from cells derived from patients. Here starting from the heart biology, we review recent advances in engineering cardiac tissues and heart-on-a-chip platforms for their use in heart regeneration and cardiotoxic/cardiotherapeutic drug screening, and then briefly conclude with characterization techniques and personalization potential of the cardiac models. PMID:26065674

  7. Cardiac Meets Skeletal: What's New in Microfluidic Models for Muscle Tissue Engineering.

    PubMed

    Visone, Roberta; Gilardi, Mara; Marsano, Anna; Rasponi, Marco; Bersini, Simone; Moretti, Matteo

    2016-01-01

    In the last few years microfluidics and microfabrication technique principles have been extensively exploited for biomedical applications. In this framework, organs-on-a-chip represent promising tools to reproduce key features of functional tissue units within microscale culture chambers. These systems offer the possibility to investigate the effects of biochemical, mechanical, and electrical stimulations, which are usually applied to enhance the functionality of the engineered tissues. Since the functionality of muscle tissues relies on the 3D organization and on the perfect coupling between electrochemical stimulation and mechanical contraction, great efforts have been devoted to generate biomimetic skeletal and cardiac systems to allow high-throughput pathophysiological studies and drug screening. This review critically analyzes microfluidic platforms that were designed for skeletal and cardiac muscle tissue engineering. Our aim is to highlight which specific features of the engineered systems promoted a typical reorganization of the engineered construct and to discuss how promising design solutions exploited for skeletal muscle models could be applied to improve cardiac tissue models and vice versa. PMID:27571058

  8. Tissue section AFM: In situ ultrastructural imaging of native biomolecules

    PubMed Central

    Graham, Helen K.; Hodson, Nigel W.; Hoyland, Judith A.; Millward-Sadler, Sarah J.; Garrod, David; Scothern, Anthea; Griffiths, Christopher E.M.; Watson, Rachel E.B.; Cox, Thomas R.; Erler, Janine T.; Trafford, Andrew W.; Sherratt, Michael J.

    2010-01-01

    Conventional approaches for ultrastructural high-resolution imaging of biological specimens induce profound changes in bio-molecular structures. By combining tissue cryo-sectioning with non-destructive atomic force microscopy (AFM) imaging we have developed a methodology that may be applied by the non-specialist to both preserve and visualize bio-molecular structures (in particular extracellular matrix assemblies) in situ. This tissue section AFM technique is capable of: i) resolving nm–µm scale features of intra- and extracellular structures in tissue cryo-sections; ii) imaging the same tissue region before and after experimental interventions; iii) combining ultrastructural imaging with complimentary microscopical and micromechanical methods. Here, we employ this technique to: i) visualize the macro-molecular structures of unstained and unfixed fibrillar collagens (in skin, cartilage and intervertebral disc), elastic fibres (in aorta and lung), desmosomes (in nasal epithelium) and mitochondria (in heart); ii) quantify the ultrastructural effects of sequential collagenase digestion on a single elastic fibre; iii) correlate optical (auto fluorescent) with ultrastructural (AFM) images of aortic elastic lamellae. PMID:20144712

  9. Laser Capture and Single Cell Genotyping from Frozen Tissue Sections.

    PubMed

    Kroneis, Thomas; Ye, Jody; Gillespie, Kathleen

    2016-01-01

    There is an increasing requirement for genetic analysis of individual cells from tissue sections. This is particularly the case for analysis of tumor cells but is also a requirement for analysis of cells in pancreas from individuals with type 1 diabetes where there is evidence of viral infection or in the analysis of chimerism in pancreas; either post-transplant or as a result of feto-maternal cell transfer.This protocol describes a strategy to isolate cells using laser microdissection and to run a 17plex PCR to discriminate between cells of haplo-identical origin (i.e., fetal and maternal cells) in pancreas tissue but other robust DNA tests could be used. In short, snap-frozen tissues are cryo-sectioned and mounted onto membrane-coated slides. Target cells are harvested from the tissue sections by laser microdissection and pressure catapulting (LMPC) prior to DNA profiling. This is based on amplification of highly repetitive yet stably inherited loci (short tandem repeats, STR) as well as the amelogenin locus for sex determination and separation of PCR products by capillary electrophoresis. PMID:26659805

  10. Culturing Mouse Cardiac Valves in the Miniature Tissue Culture System.

    PubMed

    Kruithof, Boudewijn P T; Lieber, Samuel C; Kruithof-de Julio, Marianna; Gaussin, Vincian; Goumans, Marie José

    2015-01-01

    Heart valve disease is a major burden in the Western world and no effective treatment is available. This is mainly due to a lack of knowledge of the molecular, cellular and mechanical mechanisms underlying the maintenance and/or loss of the valvular structure. Current models used to study valvular biology include in vitro cultures of valvular endothelial and interstitial cells. Although, in vitro culturing models provide both cellular and molecular mechanisms, the mechanisms involved in the 3D-organization of the valve remain unclear. While in vivo models have provided insight into the molecular mechanisms underlying valvular development, insight into adult valvular biology is still elusive. In order to be able to study the regulation of the valvular 3D-organization on tissue, cellular and molecular levels, we have developed the Miniature Tissue Culture System. In this ex vivo flow model the mitral or the aortic valve is cultured in its natural position in the heart. The natural configuration and composition of the leaflet are maintained allowing the most natural response of the valvular cells to stimuli. The valves remain viable and are responsive to changing environmental conditions. This MTCS may provide advantages on studying questions including but not limited to, how does the 3D organization affect valvular biology, what factors affect 3D organization of the valve, and which network of signaling pathways regulates the 3D organization of the valve. PMID:26555276

  11. Functional interaction between charged nanoparticles and cardiac tissue: a new paradigm for cardiac arrhythmia?

    PubMed Central

    Ruenraroengsak, Pakatip; Shevchuk, Andrew I; Korchev, Yuri E; Lab, Max J; Tetley, Teresa D; Gorelik, Julia

    2016-01-01

    Aim To investigate the effect of surface charge of therapeutic nanoparticles on sarcolemmal ionic homeostasis and the initiation of arrhythmias. Materials & methods Cultured neonatal rat myocytes were exposed to 50 nm-charged polystyrene latex nanoparticles and examined using a combination of hopping probe scanning ion conductance microscopy, optical recording of action potential characteristics and patch clamp. Results Positively charged, amine-modified polystyrene latex nanoparticles showed cytotoxic effects and induced large-scale damage to cardiomyocyte membranes leading to calcium alternans and cell death. By contrast, negatively charged, carboxyl-modified polystyrene latex nanoparticles (NegNPs) were not overtly cytotoxic but triggered formation of 50–250-nm nanopores in the membrane. Cells exposed to NegNPs revealed pro-arrhythmic events, such as delayed afterdepolarizations, reduction in conduction velocity and pathological increment of action potential duration together with an increase in ionic current throughout the membrane, carried by the nanopores. Conclusion The utilization of charged nanoparticles is a novel concept for targeting cardiac excitability. However, this unique nanoscopic investigation reveals an altered electrophysiological substrate, which sensitized the heart cells towards arrhythmias. PMID:23140503

  12. Textile-templated electrospun anisotropic scaffolds for regenerative cardiac tissue engineering.

    PubMed

    Şenel Ayaz, H Gözde; Perets, Anat; Ayaz, Hasan; Gilroy, Kyle D; Govindaraj, Muthu; Brookstein, David; Lelkes, Peter I

    2014-10-01

    For patients with end-stage heart disease, the access to heart transplantation is limited due to the shortage of donor organs and to the potential for rejection of the donated organ. Therefore, current studies focus on bioengineering approaches for creating biomimetic cardiac patches that will assist in restoring cardiac function, by repairing and/or regenerating the intrinsically anisotropic myocardium. In this paper we present a simplified, straightforward approach for creating bioactive anisotropic cardiac patches, based on a combination of bioengineering and textile-manufacturing techniques in concert with nano-biotechnology based tissue-engineering stratagems. Using knitted conventional textiles, made of cotton or polyester yarns as template targets, we successfully electrospun anisotropic three-dimensional scaffolds from poly(lactic-co-glycolic) acid (PLGA), and thermoplastic polycarbonate-urethane (PCU, Bionate(®)). The surface topography and mechanical properties of textile-templated anisotropic scaffolds significantly differed from those of scaffolds electrospun from the same materials onto conventional 2-D flat-target electrospun scaffolds. Anisotropic textile-templated scaffolds electrospun from both PLGA and PCU, supported the adhesion and proliferation of H9C2 cardiac myoblasts cell line, and guided the cardiac tissue-like anisotropic organization of these cells in vitro. All cell-seeded PCU scaffolds exhibited mechanical properties comparable to those of a human heart, but only the cells on the polyester-templated scaffolds exhibited prolonged spontaneous synchronous contractility on the entire engineered construct for 10 days in vitro at a near physiologic frequency of ∼120 bpm. Taken together, the methods described here take advantage of straightforward established textile manufacturing strategies as an efficient and cost-effective approach to engineering 3D anisotropic, elastomeric PCU scaffolds that can serve as a cardiac patch. PMID:25017096

  13. Advancing functional engineered cardiac tissues toward a preclinical model of human myocardium

    PubMed Central

    Turnbull, Irene C.; Karakikes, Ioannis; Serrao, Gregory W.; Backeris, Peter; Lee, Jia-Jye; Xie, Chaoqin; Senyei, Grant; Gordon, Ronald E.; Li, Ronald A.; Akar, Fadi G.; Hajjar, Roger J.; Hulot, Jean-Sébastien; Costa, Kevin D.

    2014-01-01

    Cardiac experimental biology and translational research would benefit from an in vitro surrogate for human heart muscle. This study investigated structural and functional properties and interventional responses of human engineered cardiac tissues (hECTs) compared to human myocardium. Human embryonic stem cell-derived cardiomyocytes (hESC-CMs, >90% troponin-positive) were mixed with collagen and cultured on force-sensing elastomer devices. hECTs resembled trabecular muscle and beat spontaneously (1.18±0.48 Hz). Microstructural features and mRNA expression of cardiac-specific genes (α-MHC, SERCA2a, and ACTC1) were comparable to human myocardium. Optical mapping revealed cardiac refractoriness with loss of 1:1 capture above 3 Hz, and cycle length dependence of the action potential duration, recapitulating key features of cardiac electrophysiology. hECTs reconstituted the Frank-Starling mechanism, generating an average maximum twitch stress of 660 μN/mm2 at Lmax, approaching values in newborn human myocardium. Dose-response curves followed exponential pharmacodynamics models for calcium chloride (EC50 1.8 mM) and verapamil (IC50 0.61 μM); isoproterenol elicited a positive chronotropic but negligible inotropic response, suggesting sarcoplasmic reticulum immaturity. hECTs were amenable to gene transfer, demonstrated by successful transduction with Ad.GFP. Such 3-D hECTs recapitulate an early developmental stage of human myocardium and promise to offer an alternative preclinical model for cardiology research.—Turnbull, I. C., Karakikes, I., Serrao, G. W., Backeris, P., Lee, J.-J., Xie, C., Senyei, G., Gordon, R. E., Li, R. A., Akar, F. G., Hajjar, R. J., Hulot, J.-S., Costa, K. D. Advancing functional engineered cardiac tissues toward a preclinical model of human myocardium. PMID:24174427

  14. The role of Wnt regulation in heart development, cardiac repair and disease: A tissue engineering perspective.

    PubMed

    Pahnke, Aric; Conant, Genna; Huyer, Locke Davenport; Zhao, Yimu; Feric, Nicole; Radisic, Milica

    2016-05-01

    Wingless-related integration site (Wnt) signaling has proven to be a fundamental mechanism in cardiovascular development as well as disease. Understanding its particular role in heart formation has helped to develop pluripotent stem cell differentiation protocols that produce relatively pure cardiomyocyte populations. The resultant cardiomyocytes have been used to generate heart tissue for pharmaceutical testing, and to study physiological and disease states. Such protocols in combination with induced pluripotent stem cell technology have yielded patient-derived cardiomyocytes that exhibit some of the hallmarks of cardiovascular disease and are therefore being used to model disease states. While FDA approval of new treatments typically requires animal experiments, the burgeoning field of tissue engineering could act as a replacement. This would necessitate the generation of reproducible three-dimensional cardiac tissues in a well-controlled environment, which exhibit native heart properties, such as cellular density, composition, extracellular matrix composition, and structure-function. Such tissues could also enable the further study of Wnt signaling. Furthermore, as Wnt signaling has been found to have a mechanistic role in cardiac pathophysiology, e.g. heart attack, hypertrophy, atherosclerosis, and aortic stenosis, its strategic manipulation could provide a means of generating reproducible and specific, physiological and pathological cardiac models. PMID:26626076

  15. Myocardial Scaffold-based Cardiac Tissue Engineering: Application of Coordinated Mechanical and Electrical Stimulations

    PubMed Central

    Wang, Bo; Wang, Guangjun; To, Filip; Butler, J. Ryan; Claude, Andrew; McLaughlin, Ronald M.; Williams, Lakiesha N.; de Jongh Curry, Amy L.; Liao, Jun

    2013-01-01

    Recently, we have developed an optimal decellularization protocol to generate 3D porcine myocardial scaffolds, which preserved natural extracellular matrix structure, mechanical anisotropy, and vasculature templates, and also showed good cell recellularization and differentiation potential. In this study, a multi-stimulation bioreactor was built to provide coordinated mechanical and electrical stimulations for facilitating stem cell differentiation and cardiac construct development. The acellular myocardial scaffolds were seeded with mesenchymal stem cells (106 cells/ml) by needle injection and subjected to 5-azacytidine treatment (3 μmol/L, 24 h) and various bioreactor conditioning protocols. We found that, after 2-day culture with mechanical (20% strain) and electrical stimulation (5 V, 1 Hz), high cell density and good cell viability were observed in the reseeded scaffold. Immunofluorescence staining demonstrated that the differentiated cells showed cardiomyocyte-like phenotype, by expressing sarcomeric α-actinin, myosin heavy chain, cardiac troponin T, connexin-43, and N-cadherin. Biaxial mechanical testing demonstrated that positive tissue remodeling took place after 2-day bioreactor conditioning (20% strain + 5 V, 1 Hz); passive mechanical properties of the 2-day and 4-day tissue constructs were comparable to the tissue constructs produced by stirring reseeding followed by 2-week static culture, implying the effectiveness and efficiency of the coordinated simulations in promoting tissue remodeling. In short, the synergistic stimulations might be beneficial not only for the quality of cardiac construct development, but also for patients by reducing the waiting time in future clinical scenarios. PMID:23923967

  16. Biomimetic perfusion and electrical stimulation applied in concert improved the assembly of engineered cardiac tissue.

    PubMed

    Maidhof, Robert; Tandon, Nina; Lee, Eun Jung; Luo, Jianwen; Duan, Yi; Yeager, Keith; Konofagou, Elisa; Vunjak-Novakovic, Gordana

    2012-11-01

    Maintenance of normal myocardial function depends intimately on synchronous tissue contraction, driven by electrical activation and on adequate nutrient perfusion in support thereof. Bioreactors have been used to mimic aspects of these factors in vitro to engineer cardiac tissue but, due to design limitations, previous bioreactor systems have yet to simultaneously support nutrient perfusion, electrical stimulation and unconstrained (i.e. not isometric) tissue contraction. To the best of our knowledge, the bioreactor system described herein is the first to integrate these three key factors in concert. We present the design of our bioreactor and characterize its capability in integrated experimental and mathematical modelling studies. We then cultured cardiac cells obtained from neonatal rats in porous, channelled elastomer scaffolds with the simultaneous application of perfusion and electrical stimulation, with controls excluding either one or both of these two conditions. After 8 days of culture, constructs grown with simultaneous perfusion and electrical stimulation exhibited substantially improved functional properties, as evidenced by a significant increase in contraction amplitude (0.23 ± 0.10% vs 0.14 ± 0.05%, 0.13 ± 0.08% or 0.09 ± 0.02% in control constructs grown without stimulation, without perfusion, or either stimulation or perfusion, respectively). Consistently, these constructs had significantly improved DNA contents, cell distribution throughout the scaffold thickness, cardiac protein expression, cell morphology and overall tissue organization compared to control groups. Thus, the simultaneous application of medium perfusion and electrical conditioning enabled by the use of the novel bioreactor system may accelerate the generation of fully functional, clinically sized cardiac tissue constructs. PMID:22170772

  17. Low temperature ultramicroincineration of thin-sectioned tissue.

    PubMed

    Hohman, W; Schraer, H

    1972-11-01

    Low temperature ultramicroincineration was employed to determine the morphological localization of "structure-bound" mineral and/or metallic elements within biological cells at the electron microscope level. This technique chemically removes organic material from thin sections of tissues with reactive, excited oxygen instead of heat as used in a furnace. The remaining ash representing the mineral/metallic ultrastructure of cells is advantageous for ultrastructural studies because incineration without applying heat is less destructive than the burning associated with high temperatures. This low temperature incineration method was applied to thin-sectioned avian shell gland mucosa, a calcium transporting system, as a sample tissue. The results include: recognition of many subcellular organelles in the ash patterns, identification of dense, ash-containing granules (possibly organic-metallic complexes) in epithelial cells which may be involved in calcium transport, description of ashed erythrocytes and collagen, comparison of ashed glutaraldehyde fixed tissue with and without osmium postfixation, description of lead-stained cells after ashing, demonstration that ash preservation is dependent upon section thickness, illustration of the fine resolution obtainable because the ash residues remain relatively near their in situ origins, discussion of technical problems in this relatively new field, and demonstration of the presence of Ca and P in the ash with electron microprobe X-ray analysis. PMID:4116522

  18. LOW TEMPERATURE ULTRAMICROINCINERATION OF THIN-SECTIONED TISSUE

    PubMed Central

    Hohman, Wayne; Schraer, Harald

    1972-01-01

    Low temperature ultramicroincineration was employed to determine the morphological localization of "structure-bound" mineral and/or metallic elements within biological cells at the electron microscope level. This technique chemically removes organic material from thin sections of tissues with reactive, excited oxygen instead of heat as used in a furnace. The remaining ash representing the mineral/metallic ultrastructure of cells is advantageous for ultrastructural studies because incineration without applying heat is less destructive than the burning associated with high temperatures. This low temperature incineration method was applied to thin-sectioned avian shell gland mucosa, a calcium transporting system, as a sample tissue. The results include: recognition of many subcellular organelles in the ash patterns, identification of dense, ash-containing granules (possibly organic-metallic complexes) in epithelial cells which may be involved in calcium transport, description of ashed erythrocytes and collagen, comparison of ashed glutaraldehyde fixed tissue with and without osmium postfixation, description of lead-stained cells after ashing, demonstration that ash preservation is dependent upon section thickness, illustration of the fine resolution obtainable because the ash residues remain relatively near their in situ origins, discussion of technical problems in this relatively new field, and demonstration of the presence of Ca and P in the ash with electron microprobe X-ray analysis. PMID:4116522

  19. Polypyrrole-contained electrospun conductive nanofibrous membranes for cardiac tissue engineering.

    PubMed

    Kai, Dan; Prabhakaran, Molamma P; Jin, Guorui; Ramakrishna, Seeram

    2011-12-01

    Cardiac tissue engineering (TE) is one of the most promising strategies to reconstruct infarct myocardium and the major challenge is to generate a bioactive substrate with suitable chemical, biological, and conductive properties, thus mimicking the extracellular matrix (ECM) both structurally and functionally. In this study, polypyrrole/poly(ε-caprolactone)/gelatin nanofibrous scaffolds were electrospun by incorporating different concentrations of polypyrrole (PPy) to PCL/gelatin (PG) solution. Morphological, chemical, mechanical, and biodegradation properties of the electrospun nanofibers were evaluated. Our data indicated that by increasing the concentration of PPy (0-30%) in the composite, the average fiber diameters reduced from 239 ± 37 nm to 191 ± 45 nm, and the tensile modulus increased from 7.9 ± 1.6 MPa to 50.3 ± 3.3 MPa. Conductive nanofibers containing 15% PPy (PPG15) exhibited the most balanced properties of conductivity, mechanical properties, and biodegradability, matching the requirements for regeneration of cardiac tissue. The cell proliferation assay, SEM, and immunostaining analysis showed that the PPG15 scaffold promote cell attachment, proliferation, interaction, and expression of cardiac-specific proteins better than PPG30. Electrospun PPG15 conductive nanofibrous scaffold could be desirable and promising substrates suitable for the regeneration of infarct myocardium and cardiac defects. PMID:22021185

  20. Electrospun composite scaffolds containing poly(octanediol-co-citrate) for cardiac tissue engineering.

    PubMed

    Prabhakaran, Molamma P; Nair, A Sreekumaran; Kai, Dan; Ramakrishna, Seeram

    2012-07-01

    A biocompatible and elastomeric nanofibrous scaffold is electrospun from a blend of poly(1,8-octanediol-co-citrate) [POC] and poly(L-lactic acid) -co-poly-(3-caprolactone) [PLCL] for application as a bioengineered patch for cardiac tissue engineering. The characterization of the scaffolds was carried out by Fourier transform infra red spectroscopy, scanning electron microscopy (SEM), and tensile measurement. The mechanical properties of the scaffolds are studied with regard to the percentage of POC incorporated with PLCL and the results of the study showed that the mechanical property and degradation behavior of the composites can be tuned with respect to the concentration of POC blended with PLCL. The composite scaffolds with POC: PLCL weight ratio of 40:60 [POC/PLCL4060] was found to have a tensile strength of 1.04 ± 0.11 MPa and Young's Modulus of 0.51 ± 0.10 MPa, comparable to the native cardiac tissue. The proliferation of cardiac myoblast cells on the electrospun POC/PLCL scaffolds was found to increase from Days 2 to 8, with the increasing concentration of POC in the composite. The morphology and cytoskeletal observation of the cells also demonstrated the biocompatibility of the POC containing scaffolds. Electrospun POC/PLCL4060 nanofibers are promising elastomeric substrates that might provide the necessary mechanical cues to cardiac muscle cells for regeneration of the heart. PMID:22328272

  1. High Resolution Magnetic Images of Planar Wave Fronts Reveal Bidomain Properties of Cardiac Tissue

    PubMed Central

    Holzer, Jenny R.; Fong, Luis E.; Sidorov, Veniamin Y.; Wikswo, John P.; Baudenbacher, Franz

    2004-01-01

    We magnetically imaged the magnetic action field and optically imaged the transmembrane potentials generated by planar wavefronts on the surface of the left ventricular wall of Langendorff-perfused isolated rabbit hearts. The magnetic action field images were used to produce a time series of two-dimensional action current maps. Overlaying epifluorescent images allowed us to identify a net current along the wavefront and perpendicular to gradients in the transmembrane potential. This is in contrast to a traditional uniform double-layer model where the net current flows along the gradient in the transmembrane potential. Our findings are supported by numerical simulations that treat cardiac tissue as a bidomain with unequal anisotropies in the intra- and extracellular spaces. Our measurements reveal the anisotropic bidomain nature of cardiac tissue during plane wave propagation. These bidomain effects play an important role in the generation of the whole-heart magnetocardiogram and cannot be ignored. PMID:15377521

  2. Experimental and theoretical description of higher order periods in cardiac tissue action potential duration

    NASA Astrophysics Data System (ADS)

    Herndon, Conner; Fenton, Flavio; Uzelac, Ilija

    Much theoretical, experimental, and clinical research has been devoted to investigating the initiation of cardiac arrhythmias by alternans, the first period doubling bifurcation in the duration of cardiac action potentials. Although period doubling above alternans has been shown to exist in many mammalian hearts, little is understood about their emergence or behavior. There currently exists no physiologically correct theory or model that adequately describes and predicts their emergence in stimulated tissue. In this talk we present experimental data of period 2, 4, and 8 dynamics and a mathematical model that describes these bifurcations. This model extends current cell models through the addition of memory and includes spatiotemporal nonlinearities arising from cellular coupling by tissue heterogeneity.

  3. Cardiac tissue enriched factors serum response factor and GATA-4 are mutual coregulators

    NASA Technical Reports Server (NTRS)

    Belaguli, N. S.; Sepulveda, J. L.; Nigam, V.; Charron, F.; Nemer, M.; Schwartz, R. J.

    2000-01-01

    Combinatorial interaction among cardiac tissue-restricted enriched transcription factors may facilitate the expression of cardiac tissue-restricted genes. Here we show that the MADS box factor serum response factor (SRF) cooperates with the zinc finger protein GATA-4 to synergistically activate numerous myogenic and nonmyogenic serum response element (SRE)-dependent promoters in CV1 fibroblasts. In the absence of GATA binding sites, synergistic activation depends on binding of SRF to the proximal CArG box sequence in the cardiac and skeletal alpha-actin promoter. GATA-4's C-terminal activation domain is obligatory for synergistic coactivation with SRF, and its N-terminal domain and first zinc finger are inhibitory. SRF and GATA-4 physically associate both in vivo and in vitro through their MADS box and the second zinc finger domains as determined by protein A pullout assays and by in vivo one-hybrid transfection assays using Gal4 fusion proteins. Other cardiovascular tissue-restricted GATA factors, such as GATA-5 and GATA-6, were equivalent to GATA-4 in coactivating SRE-dependent targets. Thus, interaction between the MADS box and C4 zinc finger proteins, a novel regulatory paradigm, mediates activation of SRF-dependent gene expression.

  4. Bimodal biophotonic imaging of the structure-function relationship in cardiac tissue

    PubMed Central

    Hucker, William J.; Ripplinger, Crystal M.; Fleming, Christine P.; Fedorov, Vadim V.; Rollins, Andrew M.; Efimov, Igor R.

    2009-01-01

    The development of systems physiology is hampered by the limited ability to relate tissue structure and function in intact organs in vivo or in vitro. Here, we show the application of a bimodal biophotonic imaging approach that employs optical coherence tomography and fluorescent imaging to investigate the structure-function relationship at the tissue level in the heart. Reconstruction of cardiac excitation and structure was limited by the depth penetration of bimodal imaging to ∼2 mm in atrial tissue, and ∼1 mm in ventricular myocardium. The subcellular resolution of optical coherence tomography clearly demonstrated that microscopic fiber orientation governs the pattern of wave propagation in functionally characterized rabbit sinoatrial and atrioventricular nodal preparations and revealed structural heterogeneities contributing to ventricular arrhythmias. The combination of this bimodal biophotonic imaging approach with histology and/or immunohistochemistry can span multiple scales of resolution for the investigation of the molecular and structural determinants of intact tissue physiology. PMID:19021392

  5. Encapsulation of cardiomyocytes in a fibrin hydrogel for cardiac tissue engineering.

    PubMed

    Yuan Ye, Kathy; Sullivan, Kelly Elizabeth; Black, Lauren Deems

    2011-01-01

    Culturing cells in a three dimensional hydrogel environment is an important technique for developing constructs for tissue engineering as well as studying cellular responses under various culture conditions in vitro. The three dimensional environment more closely mimics what the cells observe in vivo due to the application of mechanical and chemical stimuli in all dimensions (1). Three-dimensional hydrogels can either be made from synthetic polymers such as PEG-DA (2) and PLGA (3) or a number of naturally occurring proteins such as collagen (4), hyaluronic acid (5) or fibrin (6,7). Hydrogels created from fibrin, a naturally occurring blood clotting protein, can polymerize to form a mesh that is part of the body's natural wound healing processes (8). Fibrin is cell-degradable and potentially autologous (9), making it an ideal temporary scaffold for tissue engineering. Here we describe in detail the isolation of neonatal cardiomyocytes from three day old rat pups and the preparation of the cells for encapsulation in fibrin hydrogel constructs for tissue engineering. Neonatal myocytes are a common cell source used for in vitro studies in cardiac tissue formation and engineering (4). Fibrin gel is created by mixing fibrinogen with the enzyme thrombin. Thrombin cleaves fibrinopeptides FpA and FpB from fibrinogen, revealing binding sites that interact with other monomers (10). These interactions cause the monomers to self-assemble into fibers that form the hydrogel mesh. Because the timing of this enzymatic reaction can be adjusted by altering the ratio of thrombin to fibrinogen, or the ratio of calcium to thrombin, one can injection mold constructs with a number of different geometries (11,12). Further we can generate alignment of the resulting tissue by how we constrain the gel during culture (13). After culturing the engineered cardiac tissue constructs for two weeks under static conditions, the cardiac cells have begun to remodel the construct and can generate a

  6. Epigenetic Regulation of Cardiac Differentiation of Embryonic Stem Cells and Tissues.

    PubMed

    Jebeniani, Imen; Leschik, Julia; Puceat, Michel

    2016-01-01

    Specific gene transcription is a key biological process that underlies cell fate decision during embryonic development. The biological process is mediated by transcription factors which bind genomic regulatory regions including enhancers and promoters of cardiac constitutive genes. DNA is wrapped around histones that are subjected to chemical modifications. Modifications of histones further lead to repressed, activated or poised gene transcription, thus bringing another level of fine tuning regulation of gene transcription. Embryonic Stem cells (ES cells) recapitulate within embryoid bodies (i.e., cell aggregates) or in 2D culture the early steps of cardiac development. They provide in principle enough material for chromatin immunoprecipitation (ChIP), a technology broadly used to identify gene regulatory regions. Furthermore, human ES cells represent a human cell model of cardiogenesis. At later stages of development, mouse embryonic tissues allow for investigating specific epigenetic landscapes required for determination of cell identity. Herein, we describe protocols of ChIP, sequential ChIP followed by PCR or ChIP-sequencing using ES cells, embryoid bodies and cardiac specific embryonic regions. These protocols allow to investigating the epigenetic regulation of cardiac gene transcription. PMID:27285123

  7. An integrated in vitro model of perfused tumor and cardiac tissue

    PubMed Central

    2013-01-01

    Cancer and cardiovascular disease remain the two leading causes of death in the United States. Progress in treatment to reduce morbidity and mortality will include the development of new drugs. Recent advances in induced pluripotent stem cell technology, tissue engineering, and microfabrication techniques have created a unique opportunity to develop three-dimensional (3D) microphysiological systems that more accurately reflect in vivo human biology when compared with two-dimensional flat systems or animal models. Our group is working to develop 3D microphysiological systems using induced pluripotent stem cell technology that simulates the microcirculation, the cardiac muscle, and the solid tumor, and then to combine these systems into an integrated microphysiological system that simulates perfused cardiac muscle and solid tumor on a single platform. The platform will be initially validated to predict anti-cancer efficacy while minimizing cardiac muscle toxicity. A critical feature will be blood flow through a human microcirculation (capillaries and larger microvessels), which is necessary to overcome diffusion limitations of nutrients and waste products in realistic 3D cultures, and serves to integrate multiple organ systems. This is a necessary and critical feature of any platform that seeks to simulate integrated human organ systems. The results of our project should produce a new paradigm for efficient and accurate drug and toxicity screening, initially for anti-cancer drugs with minimal cardiac side effects, and a platform technology that can be eventually used to integrate multiple major organ systems of the human body. PMID:24565445

  8. 3D Extracellular Matrix from Sectioned Human Tissues

    PubMed Central

    Campbell, Catherine B; Cukierman, Edna; Artym, Vira V

    2014-01-01

    corneal endothelial cell lines produce an ECM mimicking an in vivo subendothelium, and the EHS tumor cell line produces a matrix that can be extracted to produce Matrigel, which simulates basement membrane molecular complexity including laminin, collagen IV and nidogen (Beacham, et al., 2007; Friedl and Brocker, 2000). To simulate a physiological environment even more closely, 3D matrices derived from mouse tissue slices from which cells were extracted have reportedly provided successful ECM replicas for studying in vivo cellular behavior (Cukierman, et al., 2001). Because of the important roles of the extracellular microenvironment on normal and tumor cells, we have developed protocols to produce cell-free (decellularized) 3D matrices from cryostat sections of normal and tumor human tissues. These extracted matrices can be used as a 3D tissue culture environment to analyze effects of various 3D matrices on normal and tumor cell responses and behavior. Using human pancreas and breast tissue samples, we have successfully prepared cell-free 3D ECM models, used them as cell culture substrates for a human breast cancer cell line, MDA-MB-231, and then performed immunofluorescence staining to characterize intracellular structures. A frequently observed difference between normal and tumor tissue-derived ECM environments involves the amount of deposited fibrillar collagen (Provenzano, 2008). Tumor tissues from both breast and pancreas often contain substantially more collagen than normal adjacent tissue, and this protocol preserves this difference in cell-free 3D matrices from these tissues (Vidi, et al., 2013). This 3D culture system we describe using cell-free 3D matrix provides an approach to studying cellular behavior and migratory mechanisms associated with cancer. The basic protocol describes methods for successfully extracting cells and cellular debris from human tissue cryostat sections to obtain a clean, cell-free 3D ECM for plating cell lines (Figure 1). Cellular

  9. Guided orientation of cardiomyocytes on electrospun aligned nanofibers for cardiac tissue engineering.

    PubMed

    Kai, Dan; Prabhakaran, Molamma P; Jin, Guorui; Ramakrishna, Seeram

    2011-08-01

    Cardiac tissue engineering (TE) is one of the most promising strategies to reconstruct the infarct myocardium and the major challenge involves producing a bioactive scaffold with anisotropic properties that assist in cell guidance to mimic the heart tissue. In this study, random and aligned poly(ε-caprolactone)/gelatin (PG) composite nanofibrous scaffolds were electrospun to structurally mimic the oriented extracellular matrix (ECM). Morphological, chemical and mechanical properties of the electrospun PG nanofibers were evaluated by scanning electron microscopy (SEM), water contact angle, attenuated total reflectance Fourier transform infrared spectroscopy and tensile measurements. Results indicated that PG nanofibrous scaffolds possessed smaller fiber diameters (239 ± 37 nm for random fibers and 269 ± 33 nm for aligned fibers), increased hydrophilicity, and lower stiffness compared to electrospun PCL nanofibers. The aligned PG nanofibers showed anisotropic wetting characteristics and mechanical properties, which closely match the requirements of native cardiac anisotropy. Rabbit cardiomyocytes were cultured on electrospun random and aligned nanofibers to assess the biocompatibility of scaffolds, together with its potential for cell guidance. The SEM and immunocytochemical analysis showed that the aligned PG scaffold greatly promoted cell attachment and alignment because of the biological components and ordered topography of the scaffolds. Moreover, we concluded that the aligned PG nanofibrous scaffolds could be more promising substrates suitable for the regeneration of infarct myocardium and other cardiac defects. PMID:21681953

  10. The induction of reentry in cardiac tissue. The missing link: How electric fields alter transmembrane potential

    NASA Astrophysics Data System (ADS)

    Roth, Bradley J.; Krassowska, Wanda

    1998-03-01

    This review examines the initiation of reentry in cardiac muscle by strong electric shocks. Specifically, it concentrates on the mechanisms by which electric shocks change the transmembrane potential of the cardiac membrane and create the physiological substrate required by the critical point theory for the initiation of rotors. The mechanisms examined include (1) direct polarization of the tissue by the stimulating current, as described by the one-dimensional cable model and its two- and three-dimensional extensions, (2) the presence of virtual anodes and cathodes, as described by the bidomain model with unequal anisotropy ratios of the intra- and extracellular spaces, (3) polarization of the tissue due to changing orientation of cardiac fibers, and (4) polarization of individual cells or groups of cells by the electric field ("sawtooth potential"). The importance of these mechanisms in the initiation of reentry is examined in two case studies: the induction of rotors using successive stimulation with a unipolar electrode, and the induction of rotors using cross-field stimulation. These cases reveal that the mechanism by which a unipolar stimulation induces arrhythmias can be explained in the framework of the bidomain model with unequal anisotropy ratios. In contrast, none of the examined mechanisms provide an adequate explanation for the induction of rotors by cross-field stimulation. Hence, this study emphasizes the need for further experimental and theoretical work directed toward explaining the mechanism of field stimulation.

  11. Genesis of myocardial repair with cardiac progenitor cells and tissue engineering

    PubMed Central

    Sim, Eugene K W; Haider, Husnain Kh; Lila, Nermine; Schussler, Olivier; Chachques, Juan C; Ye, Lei

    2010-01-01

    Background There is mounting evidence to suggest that the heart has regenerative potential in the event of myocardial injury. Recent studies have shown that a resident population of cardiac progenitor cells (CPCs) in the heart contains both vasculogenic and myogenic lineages. CPCs are able to migrate to the site of injury in the heart for participation in the healing process. The resident CPCs in the heart may also be activated through outside pharmacological intervention to promote their participation in the intrinsic repair process. In the light of these characteristics, CPCs provide a logical source for the heart cell therapy. During the regenerative cardiac process, stem cell niches (a specialised environment surrounding stem cells) provide crucial support needed for their maintenance. Discussion Compromised niche function may lead to the selection of stem cells that no longer depend on self-renewal factors produced by its environment. The objective of stem cell transplantation associated with tissue-engineered approaches is to create a new modality in the treatment of heart failure. The use of efficient scaffolds will aid to re-establish a favourable microenvironment for stem cell survival, multiplication, differentiation and function. Cardiac tissue engineering using natural and/or synthetic materials in this regard provides a novel possibility in cardiovascular therapeutics. PMID:27325955

  12. Effect of Twisted Fiber Anisotropy in Cardiac Tissue on Ablation with Pulsed Electric Fields

    PubMed Central

    Xie, Fei; Zemlin, Christian W.

    2016-01-01

    Background Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart. Methods We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered how tissue thickness, degree of anisotropy, and electrode configuration affect the geometry of the ablated volume. We considered two electrode configurations: two parallel needles inserted into the myocardium (“penetrating needles” configuration) and one circular electrode each on epi- and endocardium, opposing each other (“epi-endo” configuration). Results For thick tissues (10 mm) and moderate anisotropy ratio (a = 2), we find that the geometry of the ablated volume is almost unaffected by twisted anisotropy, i.e. it is approximately translationally symmetric from epi- to endocardium, for both electrode configurations. Higher anisotropy ratio (a = 10) leads to substantial variation in ablation width across the wall; these variations were more pronounced for the penetrating needle configuration than for the epi-endo configuration. For thinner tissues (4 mm, typical for human atria) and higher anisotropy ratio (a = 10), the epi-endo configuration yielded approximately translationally symmetric ablation volumes, while the penetrating electrodes configuration was much more sensitive to fiber twist. Conclusions These results suggest that the epi-endo configuration will be reliable for ablation of atrial fibrillation, independently of fiber orientation, while the penetrating electrode configuration may experience problems when the

  13. Three Potential Mechanisms for Failure of HIFU Ablation in Cardiac Tissue

    PubMed Central

    Laughner, Jacob I.; Sulkin, Matthew S.; Wu, Ziqi; Deng, Cheri X.; Efimov, Igor R.

    2012-01-01

    Background High Intensity Focused Ultrasound (HIFU) has been introduced for treatment of cardiac arrhythmias, because it offers the ability to create rapid tissue modification in confined volumes without directly contacting the myocardium. In spite of the benefits of HIFU, a number of limitations have been reported, which hindered its clinical adoption. Methods and Results In this study, we used a multimodal approach to evaluate thermal and non-thermal effects of HIFU in cardiac ablation. We designed a computer-controlled system capable of simultaneous fluorescence mapping and HIFU ablation. Using this system, linear lesions were created in isolated rabbit atria (n = 6) and point lesions were created in the ventricles of whole-heart (n = 6) preparations by applying HIFU at clinical doses (4–16W). Additionally, we evaluate the gap size in ablation lines necessary for conduction in atrial preparations (n = 4). The voltage sensitive dye di-4-ANEPPS was used to assess functional damage produced by HIFU. Optical coherence tomography and general histology were used to evaluate lesion extent. Conduction block was achieved in 1 (17%) of 6 atrial preparations with a single ablation line. Following 10 minutes of rest, 0 (0%) of 6 atrial preparations demonstrated sustained conduction block from a single ablation line. Tissue displacement of 1–3mm was observed during HIFU application due to acoustic radiation force along the lesion line. Additionally, excessive acoustic pressure and high temperature from HIFU generated cavitation causing macroscopic tissue damage. A minimum gap size of 1.5mm was found to conduct electrical activity. Conclusions This study identified three potential mechanisms responsible for the failure of HIFU ablation in cardiac tissues. Both acoustic radiation force and acoustic cavitation in conjunction with inconsistent thermal deposition can increase the risk of lesion discontinuity and result in gap sizes that promote ablation failure. PMID:22322367

  14. Wave trains induced by circularly polarized electric fields in cardiac tissues

    PubMed Central

    Feng, Xia; Gao, Xiang; Tang, Juan-Mei; Pan, Jun-Ting; Zhang, Hong

    2015-01-01

    Clinically, cardiac fibrillation caused by spiral and turbulent waves can be terminated by globally resetting electric activity in cardiac tissues with a single high-voltage electric shock, but it is usually associated with severe side effects. Presently, a promising alternative uses wave emission from heterogeneities induced by a sequence of low-voltage uniform electric field pulses. Nevertheless, this method can only emit waves locally near obstacles in turbulent waves and thereby requires multiple obstacles to globally synchronize myocardium and thus to terminate fibrillation. Here we propose a new approach using wave emission from heterogeneities induced by a low-voltage circularly polarized electric field (i.e., a rotating uniform electric field). We find that, this approach can generate circular wave trains near obstacles and they propagate outwardly. We study the characteristics of such circular wave trains and further find that, the higher-frequency circular wave trains can effectively suppress spiral turbulence. PMID:26302781

  15. Global coupling in excitable media provides a simplified description of mechanoelectrical feedback in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Alvarez-Lacalle, E.; Echebarria, B.

    2009-03-01

    Cardiac mechanoelectric feedback can play an important role in different heart pathologies. In this paper, we show that mechanoelectric models which describe both the electric propagation and the mechanic contraction of cardiac tissue naturally lead to close systems of equations with global coupling among the variables. This point is exemplified using the Nash-Panfilov model, which reduces to a FitzHugh-Nagumo-type equation with global coupling in the linear elastic regime. We explain the appearance of self-oscillatory regimes in terms of the system nullclines and describe the different dynamical attractors. Finally, we study their basin of attraction in terms of the system size and the strength of the stretch-induced currents.

  16. Fibroblast–myocyte electrotonic coupling: Does it occur in native cardiac tissue?☆

    PubMed Central

    Kohl, Peter; Gourdie, Robert G.

    2014-01-01

    Heterocellular electrotonic coupling between cardiac myocytes and non-excitable connective tissue cells has been a long-established and well-researched fact in vitro. Whether or not such coupling exists in vivo has been a matter of considerable debate. This paper reviews the development of experimental insight and conceptual views on this topic, describes evidence in favour of and against the presence of such coupling in native myocardium, and identifies directions for further study needed to resolve the riddle, perhaps less so in terms of principal presence which has been demonstrated, but undoubtedly in terms of extent, regulation, patho-physiological context, and actual relevance of cardiac myocyte–non-myocyte coupling in vivo. This article is part of a Special Issue entitled "Myocyte-Fibroblast Signalling in Myocardium." PMID:24412581

  17. Unidirectional Pinning and Hysteresis of Spatially Discordant Alternans in Cardiac Tissue

    NASA Astrophysics Data System (ADS)

    Skardal, Per Sebastian; Karma, Alain; Restrepo, Juan G.

    2012-03-01

    Spatially discordant alternans is a widely observed pattern of voltage and calcium signals in cardiac tissue that can precipitate lethal cardiac arrhythmia. Using spatially coupled iterative maps of the beat-to-beat dynamics, we explore this pattern’s dynamics in the regime of a calcium-dominated period-doubling instability at the single-cell level. We find a novel nonlinear bifurcation associated with the formation of a discontinuous jump in the amplitude of calcium alternans at nodes separating discordant regions. We show that this jump unidirectionally pins nodes by preventing their motion away from the pacing site following a pacing rate decrease but permitting motion towards this site following a rate increase. This unidirectional pinning leads to strongly history-dependent node motion that is strongly arrhythmogenic.

  18. Wave trains induced by circularly polarized electric fields in cardiac tissues.

    PubMed

    Feng, Xia; Gao, Xiang; Tang, Juan-Mei; Pan, Jun-Ting; Zhang, Hong

    2015-01-01

    Clinically, cardiac fibrillation caused by spiral and turbulent waves can be terminated by globally resetting electric activity in cardiac tissues with a single high-voltage electric shock, but it is usually associated with severe side effects. Presently, a promising alternative uses wave emission from heterogeneities induced by a sequence of low-voltage uniform electric field pulses. Nevertheless, this method can only emit waves locally near obstacles in turbulent waves and thereby requires multiple obstacles to globally synchronize myocardium and thus to terminate fibrillation. Here we propose a new approach using wave emission from heterogeneities induced by a low-voltage circularly polarized electric field (i.e., a rotating uniform electric field). We find that, this approach can generate circular wave trains near obstacles and they propagate outwardly. We study the characteristics of such circular wave trains and further find that, the higher-frequency circular wave trains can effectively suppress spiral turbulence. PMID:26302781

  19. "The state of the heart": Recent advances in engineering human cardiac tissue from pluripotent stem cells.

    PubMed

    Sirabella, Dario; Cimetta, Elisa; Vunjak-Novakovic, Gordana

    2015-08-01

    The pressing need for effective cell therapy for the heart has led to the investigation of suitable cell sources for tissue replacement. In recent years, human pluripotent stem cell research expanded tremendously, in particular since the derivation of human-induced pluripotent stem cells. In parallel, bioengineering technologies have led to novel approaches for in vitro cell culture. The combination of these two fields holds potential for in vitro generation of high-fidelity heart tissue, both for basic research and for therapeutic applications. However, this new multidisciplinary science is still at an early stage. Many questions need to be answered and improvements need to be made before clinical applications become a reality. Here we discuss the current status of human stem cell differentiation into cardiomyocytes and the combined use of bioengineering approaches for cardiac tissue formation and maturation in developmental studies, disease modeling, drug testing, and regenerative medicine. PMID:26069271

  20. Electrical stimulation directs engineered cardiac tissue to an age-matched native phenotype

    PubMed Central

    Lasher, Richard A; Pahnke, Aric Q; Johnson, Jeffrey M; Sachse, Frank B

    2012-01-01

    Quantifying structural features of native myocardium in engineered tissue is essential for creating functional tissue that can serve as a surrogate for in vitro testing or the eventual replacement of diseased or injured myocardium. We applied three-dimensional confocal imaging and image analysis to quantitatively describe the features of native and engineered cardiac tissue. Quantitative analysis methods were developed and applied to test the hypothesis that environmental cues direct engineered tissue toward a phenotype resembling that of age-matched native myocardium. The analytical approach was applied to engineered cardiac tissue with and without the application of electrical stimulation as well as to age-matched and adult native tissue. Individual myocytes were segmented from confocal image stacks and assigned a coordinate system from which measures of cell geometry and connexin-43 spatial distribution were calculated. The data were collected from 9 nonstimulated and 12 electrically stimulated engineered tissue constructs and 5 postnatal day 12 and 7 adult hearts. The myocyte volume fraction was nearly double in stimulated engineered tissue compared to nonstimulated engineered tissue (0.34 ± 0.14 vs 0.18 ± 0.06) but less than half of the native postnatal day 12 (0.90 ± 0.06) and adult (0.91 ± 0.04) myocardium. The myocytes under electrical stimulation were more elongated compared to nonstimulated myocytes and exhibited similar lengths, widths, and heights as in age-matched myocardium. Furthermore, the percentage of connexin-43-positive membrane staining was similar in the electrically stimulated, postnatal day 12, and adult myocytes, whereas it was significantly lower in the nonstimulated myocytes. Connexin-43 was found to be primarily located at cell ends for adult myocytes and irregularly but densely clustered over the membranes of nonstimulated, stimulated, and postnatal day 12 myocytes. These findings support our hypothesis and reveal that the

  1. Sensitivity and Specificity of Cardiac Tissue Discrimination Using Fiber-Optics Confocal Microscopy.

    PubMed

    Huang, Chao; Sachse, Frank B; Hitchcock, Robert W; Kaza, Aditya K

    2016-01-01

    Disturbances of the cardiac conduction system constitute a major risk after surgical repair of complex cases of congenital heart disease. Intraoperative identification of the conduction system may reduce the incidence of these disturbances. We previously developed an approach to identify cardiac tissue types using fiber-optics confocal microscopy and extracellular fluorophores. Here, we applied this approach to investigate sensitivity and specificity of human and automated classification in discriminating images of atrial working myocardium and specialized tissue of the conduction system. Two-dimensional image sequences from atrial working myocardium and nodal tissue of isolated perfused rodent hearts were acquired using a fiber-optics confocal microscope (Leica FCM1000). We compared two methods for local application of extracellular fluorophores: topical via pipette and with a dye carrier. Eight blinded examiners evaluated 162 randomly selected images of atrial working myocardium (n = 81) and nodal tissue (n = 81). In addition, we evaluated the images using automated classification. Blinded examiners achieved a sensitivity and specificity of 99.2 ± 0.3% and 98.0 ± 0.7%, respectively, with the dye carrier method of dye application. Sensitivity and specificity was similar for dye application via a pipette (99.2 ± 0.3% and 94.0 ± 2.4%, respectively). Sensitivity and specificity for automated methods of tissue discrimination were similarly high. Human and automated classification achieved high sensitivity and specificity in discriminating atrial working myocardium and nodal tissue. We suggest that our findings facilitate clinical translation of fiber-optics confocal microscopy as an intraoperative imaging modality to reduce the incidence of conduction disturbances during surgical correction of congenital heart disease. PMID:26808149

  2. Sensitivity and Specificity of Cardiac Tissue Discrimination Using Fiber-Optics Confocal Microscopy

    PubMed Central

    Huang, Chao; Sachse, Frank B.; Hitchcock, Robert W.; Kaza, Aditya K.

    2016-01-01

    Disturbances of the cardiac conduction system constitute a major risk after surgical repair of complex cases of congenital heart disease. Intraoperative identification of the conduction system may reduce the incidence of these disturbances. We previously developed an approach to identify cardiac tissue types using fiber-optics confocal microscopy and extracellular fluorophores. Here, we applied this approach to investigate sensitivity and specificity of human and automated classification in discriminating images of atrial working myocardium and specialized tissue of the conduction system. Two-dimensional image sequences from atrial working myocardium and nodal tissue of isolated perfused rodent hearts were acquired using a fiber-optics confocal microscope (Leica FCM1000). We compared two methods for local application of extracellular fluorophores: topical via pipette and with a dye carrier. Eight blinded examiners evaluated 162 randomly selected images of atrial working myocardium (n = 81) and nodal tissue (n = 81). In addition, we evaluated the images using automated classification. Blinded examiners achieved a sensitivity and specificity of 99.2±0.3% and 98.0±0.7%, respectively, with the dye carrier method of dye application. Sensitivity and specificity was similar for dye application via a pipette (99.2±0.3% and 94.0±2.4%, respectively). Sensitivity and specificity for automated methods of tissue discrimination were similarly high. Human and automated classification achieved high sensitivity and specificity in discriminating atrial working myocardium and nodal tissue. We suggest that our findings facilitate clinical translation of fiber-optics confocal microscopy as an intraoperative imaging modality to reduce the incidence of conduction disturbances during surgical correction of congenital heart disease. PMID:26808149

  3. Chronic obstructive pulmonary disease and cardiac comorbidities: A cross-sectional study

    PubMed Central

    Kaushal, Mohit; Shah, Parth S; Shah, Arti D; Francis, Stani A; Patel, Nihar V; Kothari, Kavit K

    2016-01-01

    Introduction: Chronic obstructive pulmonary disease (COPD) is a global health issue with cigarette smoking being an important risk factor. COPD affects pulmonary blood vessels, right ventricle, as well as left ventricle leading to the development of pulmonary hypertension (PH), cor-pulmonale (COR-P), right and left ventricular dysfunction. Echocardiography provides a rapid, noninvasive, portable, and accurate method to evaluate cardiac functions. Early diagnoses and intervention for cardiac comorbidities would reduce mortalities. Materials and Methods: A cross-sectional study. Total 50 patients of moderate to severe COPD according to GOLD guidelines were taken from Department of Respiratory Medicine, Smt. B. K. Shah Medical Institute and Research Centre, Vadodara. All patients underwent investigations such as chest X-ray PA view, ECG, and spirometry followed by two-dimensional echocardiography. Results: We investigated 49 males and 1 female patients ranging from 35 to 80 years of age. Twenty-nine individuals were of moderate COPD and twenty-one of severe COPD. Of these cases 29 had left ventricular diastolic dysfunction (LVDD) changes, 24 were diagnosed with PH and 16 had changes of COR-P. The study showed the linear relation between the severity of LVDD, PH, and COR-P with the severity of COPD. Conclusion: Our study put emphasis on early cardiac screening of all COPD patients which will be helpful in the assessment of the prognosis and will further assist in identifying the individuals likely to suffer increase morbidity and mortality.

  4. Experimental high-intensity focused ultrasound lesion formation in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Muratore, Robert; Kalisz, Andrew; Lee, Paul; Lizzi, Frederic; Fujikura, Kana; Otsuka, Ryo; Homma, Shunichi

    2001-05-01

    High-intensity focused ultrasound (HIFU) (4.5-7.5 MHz) was used to form lesions in cardiac tissue, with an ultimate objective of treating conditions such as hypertrophic cardiomyopathy and ventricular tachycardia. Ultrasound attenuation coefficients were experimentally determined in vitro for calf myocardial tissue, both muscle and pericardial fat. These coefficients were employed in computational models of linear beam propagation, tissue heating profiles and thermal lesion formation for a variety of focused transducers. Modeling was performed for continuous and pulsed exposures. These models suggested initial power levels and exposure durations for in vitro experiments on calf ventricles and septa and ex vivo experiments on canine whole hearts. Repeatability of lesion size and placement was studied as power and exposure parameters varied around the initial values. With these experimental results, power and exposure parameters were selected to create lesions in vivo in canine ventricles and septa in open-chest, anesthetized dogs. Pulsed exposures were synchronized to cardiac and respiration cycles to ensure accurate placement of the lesions. These initial in vivo experiments showed that HIFU treatments in the beating heart are feasible; they also identified refinements that are now being implemented for better control of lesion size and placement. [Work supported by NCI and NHLBI Grant 5R01 CA84588.

  5. Cardiac arrhythmogenesis in urban air pollution: Optical mapping in a tissue-engineered model

    NASA Astrophysics Data System (ADS)

    Bien, Harold H.

    Recent epidemiological evidence has implicated particulate matter air pollution in cardiovascular disease. We hypothesized that inflammatory mediators released from lung macrophages after exposure to particulate matter predisposes the heart to disturbances in rhythm. Using a rational design approach, a fluorescent optical mapping system was devised to image spatiotemporal patterns of excitation in a tissue engineered model of cardiac tissue. Algorithms for automated data analysis and characterization of rhythm stability were developed, implemented, and verified. Baseline evaluation of spatiotemporal instability patterns in normal cardiac tissue was performed for comparison to an in-vitro model of particulate matter air pollution exposure. Exposure to particulate-matter activated alveolar macrophage conditioned media resulted in paradoxical functional changes more consistent with improved growth. These findings might be indicative of a "stress" response to particulate-matter induced pulmonary inflammation, or may be specific to the animal model (neonatal rat) employed. In the pursuit of elucidating the proposed pathway, we have also furthered our understanding of fundamental behaviors of arrhythmias in general and established a model where further testing might ultimately reveal the mechanism for urban air pollution associated cardiovascular morbidity.

  6. Volume regulation mechanisms in Rana castebeiana cardiac tissue under hyperosmotic stress.

    PubMed

    Cruz, Laura N; Souza, Marta M

    2008-01-01

    Volume changes of cardiac tissue under hyperosmotic stress in Rana catesbeiana were characterized by the identification of the osmolytes involved and the possible regulatory processes activated by both abrupt and gradual changes in media osmolality (from 220 to 280mosmol/kg H(2)O). Slices of R. catesbeiana cardiac tissue were subjected to hyperosmotic shock, and total tissue Na(+), K(+), Cl(-) and ninhydrin-positive substances were measured. Volume changes were also induced in the presence of transport inhibitors to identify osmolyte pathways. The results show a maximum volume loss to 90.86+/-0.73% of the original volume (measured as 9% decrease in wet weight) during abrupt hyperosmotic shock. However, during a gradual osmotic challenge the volume was never significantly different from that of the control. During both types of hyperosmotic shock, we observed an increase in Na(+) but no significant change in Cl(-) contents. Additionally, we found no change in ninhydrin-positive substances during any osmotic challenge. Pharmacological analyses suggest the involvement of the Na(+)/H(+) exchanger, and perhaps the HCO(3)(-)/Cl(-) exchanger. There is indirect evidence for decrease in Na(+)/K(+)-ATPase activity. The Na(+) fluxes seem to result from Mg(2+) signaling, as saline rich in Mg(2+) enhances the regulatory volume increase, followed by a higher intracellular Na(+) content. The volume maintenance mechanisms activated during the gradual osmotic change are similar to that activated by abrupt osmotic shock. PMID:18457937

  7. A Java application for tissue section image analysis.

    PubMed

    Kamalov, R; Guillaud, M; Haskins, D; Harrison, A; Kemp, R; Chiu, D; Follen, M; MacAulay, C

    2005-02-01

    The medical industry has taken advantage of Java and Java technologies over the past few years, in large part due to the language's platform-independence and object-oriented structure. As such, Java provides powerful and effective tools for developing tissue section analysis software. The background and execution of this development are discussed in this publication. Object-oriented structure allows for the creation of "Slide", "Unit", and "Cell" objects to simulate the corresponding real-world objects. Different functions may then be created to perform various tasks on these objects, thus facilitating the development of the software package as a whole. At the current time, substantial parts of the initially planned functionality have been implemented. Getafics 1.0 is fully operational and currently supports a variety of research projects; however, there are certain features of the software that currently introduce unnecessary complexity and inefficiency. In the future, we hope to include features that obviate these problems. PMID:15652632

  8. Multicolor immunophenotyping of tissue sections by laser scanning cytometry (LSC)

    NASA Astrophysics Data System (ADS)

    Tarnok, Attila; Gerstner, Andreas O.; Lenz, Dominik; Osmancik, Pavel; Schneider, Peter; Trumpfheller, Christine; Racz, Pal; Tenner-Racz, Klara

    2002-05-01

    In lymphatic organs the quantitative analysis of the spatial distribution of leukocytes would give relevant information about alterations during diseases (leukemia, HIV, AIDS) and their therapeutic regimen. Analysis of them in solid tissues is difficult to perform but would yield important data in a variety of clinical and experimental settings. We have developed an automated analysis method for LSC suitable for archived or fresh biopsy material of human lymph nodes and tonsils. Sections are stained with PI for DNA and up to three antigens using direct or indirect immunofluorescence staining. Measurement is triggered on DNA-fluorescence (Argon Laser). Due to the heterogeneity in cell density measurements are repeatedly performed at different threshold levels (low threshold: regions of low cellular density, germinal centers; high threshold: dense regions, mantle zone). Data are acquired by single- (Ar) or dual-laser excitation (Ar-HeNe) in order to determine data from single- (FITC), up to triple-staining (FITC/PE-Cy5/APC). Percentage and cellular density of cell-subsets is quantified in different structural regions of the specimen. Comparison with manual analysis of identical specimens showed very good correlation. With LSC a semi-automated operator-independent and immunophenotyping of lymphatic tissues with simultaneously up to four antibodies is possible. This technique should yield new insight into processes during diseases and should help to quantify the success of therapeutic interventions.

  9. Correlation-based discrimination between cardiac tissue and blood for segmentation of 3D echocardiographic images

    NASA Astrophysics Data System (ADS)

    Saris, Anne E. C. M.; Nillesen, Maartje M.; Lopata, Richard G. P.; de Korte, Chris L.

    2013-03-01

    Automated segmentation of 3D echocardiographic images in patients with congenital heart disease is challenging, because the boundary between blood and cardiac tissue is poorly defined in some regions. Cardiologists mentally incorporate movement of the heart, using temporal coherence of structures to resolve ambiguities. Therefore, we investigated the merit of temporal cross-correlation for automated segmentation over the entire cardiac cycle. Optimal settings for maximum cross-correlation (MCC) calculation, based on a 3D cross-correlation based displacement estimation algorithm, were determined to obtain the best contrast between blood and myocardial tissue over the entire cardiac cycle. Resulting envelope-based as well as RF-based MCC values were used as additional external force in a deformable model approach, to segment the left-ventricular cavity in entire systolic phase. MCC values were tested against, and combined with, adaptive filtered, demodulated RF-data. Segmentation results were compared with manually segmented volumes using a 3D Dice Similarity Index (3DSI). Results in 3D pediatric echocardiographic images sequences (n = 4) demonstrate that incorporation of temporal information improves segmentation. The use of MCC values, either alone or in combination with adaptive filtered, demodulated RF-data, resulted in an increase of the 3DSI in 75% of the cases (average 3DSI increase: 0.71 to 0.82). Results might be further improved by optimizing MCC-contrast locally, in regions with low blood-tissue contrast. Reducing underestimation of the endocardial volume due to MCC processing scheme (choice of window size) and consequential border-misalignment, could also lead to more accurate segmentations. Furthermore, increasing the frame rate will also increase MCC-contrast and thus improve segmentation.

  10. Controlling activation site density by low-energy far-field stimulation in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Hörning, Marcel; Takagi, Seiji; Yoshikawa, Kenichi

    2012-06-01

    Tachycardia and fibrillation are potentially fatal arrhythmias associated with the formation of rotating spiral waves in the heart. Presently, the termination of these types of arrhythmia is achieved by use of antitachycardia pacing or cardioversion. However, these techniques have serious drawbacks, in that they either have limited application or produce undesirable side effects. Low-energy far-field stimulation has recently been proposed as a superior therapy. This proposed therapeutic method would exploit the phenomenon in which the application of low-energy far-field shocks induces a large number of activation sites (“virtual electrodes”) in tissue. It has been found that the formation of such sites can lead to the termination of undesired states in the heart and the restoration of normal beating. In this study we investigate a particular aspect of this method. Here we seek to determine how the activation site density depends on the applied electric field through in vitro experiments carried out on neonatal rat cardiac tissue cultures. The results indicate that the activation site density increases exponentially as a function of the intracellular conductivity and the level of cell isotropy. Additionally, we report numerical results obtained from bidomain simulations of the Beeler-Reuter model that are quantitatively consistent with our experimental results. Also, we derive an intuitive analytical framework that describes the activation site density and provides useful information for determining the ratio of longitudinal to transverse conductivity in a cardiac tissue culture. The results obtained here should be useful in the development of an actual therapeutic method based on low-energy far-field pacing. In addition, they provide a deeper understanding of the intrinsic properties of cardiac cells.

  11. Unpinning of rotating spiral waves in cardiac tissues by circularly polarized electric fields

    NASA Astrophysics Data System (ADS)

    Feng, Xia; Gao, Xiang; Pan, De-Bei; Li, Bing-Wei; Zhang, Hong

    2014-04-01

    Spiral waves anchored to obstacles in cardiac tissues may cause lethal arrhythmia. To unpin these anchored spirals, comparing to high-voltage side-effect traditional therapies, wave emission from heterogeneities (WEH) induced by the uniform electric field (UEF) has provided a low-voltage alternative. Here we provide a new approach using WEH induced by the circularly polarized electric field (CPEF), which has higher success rate and larger application scope than UEF, even with a lower voltage. And we also study the distribution of the membrane potential near an obstacle induced by CPEF to analyze its mechanism of unpinning. We hope this promising approach may provide a better alternative to terminate arrhythmia.

  12. Cardiac Extracellular Matrix-Fibrin Hybrid Scaffolds with Tunable Properties for Cardiovascular Tissue Engineering

    PubMed Central

    Williams, Corin; Budina, Erica; Stoppel, Whitney L.; Sullivan, Kelly E.; Emani, Sirisha; Emani, Sitaram M.; Black, Lauren D.

    2014-01-01

    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. PMID:25463503

  13. In vitro study of electroactive tetraaniline-containing thermosensitive hydrogels for cardiac tissue engineering.

    PubMed

    Cui, Haitao; Liu, Yadong; Cheng, Yilong; Zhang, Zhe; Zhang, Peibiao; Chen, Xuesi; Wei, Yen

    2014-04-14

    Injectable hydrogels made of degradable biomaterials can function as both physical support and cell scaffold in preventing infarct expansion and promoting cardiac repair in myocardial infarction therapy. Here, we report in situ hydrogels consisting of thermosensitive PolyNIPAM-based copolymers and electroactive tetraaniline (TA). Studies showed that the addition of 2-methylene-1,3-dioxepane (MDO) provided the PolyNIPAM-based gel with biodegradability, and the introduction of tetraaniline endowed these copolymers with desirable electrical properties and antioxidant activities. The encapsulated H9c2 cells (rat cardiac myoblast) remained highly viable in the gel matrices. In vivo gel formation and histological analyses were performed in rats by subcutaneous injection and excellent biocompatibility was observed. Furthermore, the proliferation and intracellular calcium transients of H9c2 cells were also studied with (and without) electrical stimuli. Both in vitro and in vivo results demonstrated that electroactive hydrogel may be used as a promising injectable biomaterial for cardiac tissue engineering. PMID:24597966

  14. Bone marrow transplantation modulates tissue macrophage phenotype and enhances cardiac recovery after subsequent acute myocardial infarction

    PubMed Central

    Protti, Andrea; Mongue-Din, Heloise; Mylonas, Katie J.; Sirker, Alexander; Sag, Can Martin; Swim, Megan M.; Maier, Lars; Sawyer, Greta; Dong, Xuebin; Botnar, Rene; Salisbury, Jon; Gray, Gillian A.; Shah, Ajay M.

    2016-01-01

    Background Bone marrow transplantation (BMT) is commonly used in experimental studies to investigate the contribution of BM-derived circulating cells to different disease processes. During studies investigating the cardiac response to acute myocardial infarction (MI) induced by permanent coronary ligation in mice that had previously undergone BMT, we found that BMT itself affects the remodelling response. Methods and results Compared to matched naive mice, animals that had previously undergone BMT developed significantly less post-MI adverse remodelling, infarct thinning and contractile dysfunction as assessed by serial magnetic resonance imaging. Cardiac rupture in male mice was prevented. Histological analysis showed that the infarcts of mice that had undergone BMT had a significantly higher number of inflammatory cells, surviving cardiomyocytes and neovessels than control mice, as well as evidence of significant haemosiderin deposition. Flow cytometric and histological analyses demonstrated a higher number of alternatively activated (M2) macrophages in myocardium of the BMT group compared to control animals even before MI, and this increased further in the infarcts of the BMT mice after MI. Conclusions The process of BMT itself substantially alters tissue macrophage phenotype and the subsequent response to acute MI. An increase in alternatively activated macrophages in this setting appears to enhance cardiac recovery after MI. PMID:26688473

  15. The Multi-Domain Fibroblast/Myocyte Coupling in the Cardiac Tissue: A Theoretical Study.

    PubMed

    Greisas, Ariel; Zlochiver, Sharon

    2016-09-01

    Cardiac fibroblast proliferation and concomitant collagenous matrix accumulation (fibrosis) develop during multiple cardiac pathologies. Recent studies have demonstrated direct electrical coupling between myocytes and fibroblasts in vitro, and assessed the electrophysiological implications of such coupling. However, in the living tissues, such coupling has not been demonstrated, and only indirect coupling via the extracellular space is likely to exist. In this study we employed a multi-domain model to assess the modulation of the cardiac electrophysiological properties by neighboring fibroblasts assuming only indirect coupling. Numerical simulations in 1D and 2D human atrial models showed that extracellular coupling sustains a significant impact on conduction velocity (CV) and a less significant effect on the action potential duration. Both CV and the slope of the CV restitution increased with increasing fibroblast density. This effect was more substantial for lower extracellular conductance. In 2D, spiral waves exhibited reduced frequency with increasing fibroblast density, and the propensity of wavebreaks and complex dynamics at high pacing rates significantly increased. PMID:27150222

  16. Immunohistochemical detection of Lawsonia intracellularis in tissue sections from pigs.

    PubMed

    Szczotka, A; Stadejek, T; Zmudzki, J; Nowak, A; Osiński, Z; Pejsak, Z

    2011-01-01

    The aim of the present study was to develop an immunohistochemical method (IHC) for detection of Lawsonia intracellularis (L. intracellularis) in formalin-fixed, paraffin embedded sections of intestines from pigs and to implement this method in differential diagnosis of swine diseases with diarrhea in postweaning pigs. The study was conducted on 165 sections of intestines (ileum, caecum and colon) collected from 76 pigs, representing 42 Polish pig farms. The animals included in the analysis suffered from diarrhea, with bloody or grey to brown feces, and were suspected of porcine proliferative enteropathy (PPE). Sections of intestines were analyzed for the presence of L. intracellularis by polymerase chain reaction (PCR) and IHC. Among 165 intestinal samples from pigs with diarrhea, L. intracellularis DNA was detected by PCR in 33 (20.0%) samples. In this group, 30 samples (18.2% of all the samples tested) were also found positive in IHC, while only 3 (1.8%) were IHC-negative. One hundred thirty-two (80.0%) samples were negative in both tests. The PCR- and IHC-positive samples originated from 11 pigs, 4- to 20-week old, from 8 farms. L. intracellularis antigen was visualized by IHC mostly in intestinal crypts and/or in mononuclear cells of the lamina propria). The positive signal in epithelial cells was observed close to the luminal borders, creating typical specifically stained rims around the crypt lumina. The results of the present study further confirm the usefulness of IHC in the detection of L. intracellularis antigen in the intestinal tissues. PMID:22439321

  17. The Current Status of iPS Cells in Cardiac Research and Their Potential for Tissue Engineering and Regenerative Medicine

    PubMed Central

    Martins, Ana M.; Vunjak-Novakovic, Gordana

    2015-01-01

    The recent availability of human cardiomyocytes derived from induced pluripotent stem (iPS) cells opens new opportunities to build in vitro models of cardiac disease, screening for new drugs, and patient-specific cardiac therapy. Notably, the use of iPS cells enables studies in the wide pool of genotypes and phenotypes. We describe progress in reprogramming of induced pluripotent stem (iPS) cells towards the cardiac lineage/differentiation. The focus is on challenges of cardiac disease modeling using iPS cells and their potential to produce safe, effective and affordable therapies/applications with the emphasis of cardiac tissue engineering. We also discuss implications of human iPS cells to biological research and some of the future needs. PMID:24425421

  18. Thermal welding of biological tissues derived from porcine aorta for manufacturing bioprosthetic cardiac valves.

    PubMed

    Figueiredo, Rubem L P; Dantas, Maria Sylvia Silva; Oréfice, Rodrigo L

    2011-08-01

    Sutures in cardiac valve bioprostheses have several disadvantages as they have to be manually processed and the suturing region is always a mechanically weak spot. Thermal welding of biological tissues has been evaluated as a means of replacing sutures by the direct application of heat to tissues. The mechanical strength of the welds increased up to 50°C and with lower degrees of humidity and longer times of welding. Chemical fixation was essential for the stability of the weld during re-hydration. The average mechanical strength of the welds (0.87 MPa) was lower than the strength of sutures (1.36 MPa) but some results showed strengths that were similar to sutures. Raman and electron micrographs showed that weld formation is primarily associated with chemical bonds between collagen fibers rather than chain flow and interpenetration. PMID:21479631

  19. The Dip in the Anodal Strength-Interval Curve in Cardiac Tissue

    NASA Astrophysics Data System (ADS)

    Kandel, Sunil; Roth, Bradley J.

    2012-10-01

    Heart disease -- specifically ventricular fibrillation -- is the leading cause of death in the United States. The most common treatment for this lethal arrhythmia is defibrillation: application of a strong electrical shock that resets the heart to its normal rhythm. The goal of this project is to obtain a better understanding of how anodal (hyperpolarizing) shocks affect the heart by using numerical simulations. To accomplish this goal, we will test four hypotheses to find the response of refractory tissue to an anodal shock. We will use bidomain model; the state-of-the-art mathematical description of how cardiac tissue responds to an electric shock. The innovative feature of this proposal is to integrate the bidomain model with an ion channel model (Luo-Rudy model, 1994) that includes intracellular calcium dynamics to get a detailed calculation of the mechanism of the excitation and to understand the electrical behavior of the heart, which is important for pacing and defibrillation.

  20. Carbon Nanohorns Promote Maturation of Neonatal Rat Ventricular Myocytes and Inhibit Proliferation of Cardiac Fibroblasts: a Promising Scaffold for Cardiac Tissue Engineering.

    PubMed

    Wu, Yujing; Shi, Xiaoli; Li, Yi; Tian, Lei; Bai, Rui; Wei, Yujie; Han, Dong; Liu, Huiliang; Xu, Jianxun

    2016-12-01

    Cardiac tissue engineering (CTE) has developed rapidly, but a great challenge remains in finding practical scaffold materials for the construction of engineered cardiac tissues. Carbon nanohorns (CNHs) may be a potential candidate due to their special structure and properties. The purpose of this study was to assess the effect of CNHs on the biological behavior of neonatal rat ventricular myocytes (NRVMs) for CTE applications. CNHs were incorporated into collagen to form growth substrates for NRVMs. Transmission electron microscopy (TEM) observations demonstrated that CNHs exhibited a good affinity to collagen. Moreover, it was found that CNH-embedded substrates enhanced adhesion and proliferation of NRVMs. Immunohistochemical staining, western blot analysis, and intracellular calcium transient measurements indicated that the addition of CNHs significantly increased the expression and maturation of electrical and mechanical proteins (connexin-43 and N-cadherin). Bromodeoxyuridine staining and a Cell Counting Kit-8 assay showed that CNHs have the ability to inhibit the proliferation of cardiac fibroblasts. These findings suggest that CNHs can have a valuable effect on the construction of engineered cardiac tissues and may be a promising scaffold for CTE. PMID:27263018

  1. Carbon Nanohorns Promote Maturation of Neonatal Rat Ventricular Myocytes and Inhibit Proliferation of Cardiac Fibroblasts: a Promising Scaffold for Cardiac Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Wu, Yujing; Shi, Xiaoli; Li, Yi; Tian, Lei; Bai, Rui; Wei, Yujie; Han, Dong; Liu, Huiliang; Xu, Jianxun

    2016-06-01

    Cardiac tissue engineering (CTE) has developed rapidly, but a great challenge remains in finding practical scaffold materials for the construction of engineered cardiac tissues. Carbon nanohorns (CNHs) may be a potential candidate due to their special structure and properties. The purpose of this study was to assess the effect of CNHs on the biological behavior of neonatal rat ventricular myocytes (NRVMs) for CTE applications. CNHs were incorporated into collagen to form growth substrates for NRVMs. Transmission electron microscopy (TEM) observations demonstrated that CNHs exhibited a good affinity to collagen. Moreover, it was found that CNH-embedded substrates enhanced adhesion and proliferation of NRVMs. Immunohistochemical staining, western blot analysis, and intracellular calcium transient measurements indicated that the addition of CNHs significantly increased the expression and maturation of electrical and mechanical proteins (connexin-43 and N-cadherin). Bromodeoxyuridine staining and a Cell Counting Kit-8 assay showed that CNHs have the ability to inhibit the proliferation of cardiac fibroblasts. These findings suggest that CNHs can have a valuable effect on the construction of engineered cardiac tissues and may be a promising scaffold for CTE.

  2. Optical recording of calcium currents during impulse conduction in cardiac tissue.

    PubMed

    Jousset, Florian; Rohr, Stephan

    2015-04-01

    We explore the feasibility of obtaining a spatially resolved picture of [Formula: see text] inward currents ([Formula: see text]) in multicellular cardiac tissue by differentiating optically recorded [Formula: see text] transients that accompany propagating action potentials. Patterned growth strands of neonatal rat ventricular cardiomyocytes were stained with the [Formula: see text] indicators Fluo-4 or Fluo-4FF. Preparations were stimulated at 1 Hz, and [Formula: see text] transients were recorded with high spatiotemporal resolution ([Formula: see text], 2 kHz analog bandwidth) with a photodiode array. Signals were differentiated after appropriate digital filtering. Differentiation of [Formula: see text] transients resulted in optically recorded calcium currents (ORCCs) that carried the temporal and pharmacological signatures of L-type [Formula: see text] inward currents: the time to peak amounted to [Formula: see text] (Fluo-4FF) and [Formula: see text] (Fluo-4), full-width at half-maximum was [Formula: see text], and ORCCs were completely suppressed by [Formula: see text][Formula: see text]. Also, and as reported before from patch-clamp studies, caffeine reversibly depressed the amplitude of ORCCs. The results demonstrate that the differentiation of [Formula: see text] transients can be used to obtain a spatially resolved picture of the initial phase of [Formula: see text] in cardiac tissue and to assess relative changes of activation/fast inactivation of [Formula: see text] following pharmacological interventions. PMID:26158001

  3. Feasibility of a nanomaterial-tissue patch for vascular and cardiac reconstruction.

    PubMed

    Ostdiek, Allison M; Ivey, Jan R; Hansen, Sarah A; Gopaldas, Raja; Grant, Sheila A

    2016-04-01

    Vascular and cardiac reconstruction involves the use of biological patches to treat trauma and defects. An in vivo study was performed to determine the remodeling and biologic effects of novel nanostructured vascular patches with and without gold nanoparticles. Porcine vascular tissue was decellularized and conjugated with gold nanoparticles to evaluate if integration would occur while avoiding rupture and stenosis. Swine underwent a bilateral patch angioplasty of the carotid arteries with experimental patches on the right and control patches of bovine pericardium on the left. Animals were sacrificed after surgery and at 3 and 9 weeks. Ultrasound was performed during surgery, every 3 weeks, and before euthanasia. Endothelial regeneration was examined using Evans Blue dye and histology using Trichrome and H&E. There was a 100% success rate of implantation with 0% mortality. All patches were patent on ultrasound. At 3 weeks, experimental patches had regenerating endothelial cell growth and normal healing responses. At 9 weeks, the experimental patches demonstrated excellent integration. Histology demonstrated cellular in-growth into the experimental patches and no major immune reactions. This is one of the first studies to demonstrate the feasibility of nanomaterial-tissue patches for vascular and cardiac reconstruction. PMID:25891427

  4. Design of a Novel Composite H2 S-Releasing Hydrogel for Cardiac Tissue Repair.

    PubMed

    Mauretti, Arianna; Neri, Annalisa; Kossover, Olga; Seliktar, Dror; Nardo, Paolo Di; Melino, Sonia

    2016-06-01

    The design of 3D scaffolds is a crucial step in the field of regenerative medicine. Scaffolds should be degradable and bioresorbable as well as display good porosity, interconnecting pores, and topographic features; these properties favour tissue integration and vascularization. These requirements could be fulfilled by hybrid hydrogels using a combination of natural and synthetic components. Here, the mechanical and biological properties of a polyethylene glycol-fibrinogen hydrogel (PFHy) are improved in order to favour the proliferation and differentiation of human Sca-1(pos) cardiac progenitor cells (hCPCs). PFHys are modified by embedding air- or perfluorohexane-filled bovine serum albumin microbubbles (MBs) and characterized. Changes in cell morphology are observed in MBs-PFHys, suggesting that MBs could enhance the formation of bundles of cells and influence the direction of the spindle growth. The properties of MBs as carriers of active macromolecules are also exploited. For the first time, enzyme-coated MBs have been used as systems for the production of hydrogen sulfide (H2 S)-releasing scaffolds. Novel H2 S-releasing PFHys are produced, which are able to improve the growth of hCPCs. This novel 3D cell-scaffold system will allow the assessment of the effects of H2 S on the cardiac muscle regeneration with its potential applications in tissue repair. PMID:26857526

  5. Electrically conductive gold nanoparticle-chitosan thermosensitive hydrogels for cardiac tissue engineering.

    PubMed

    Baei, Payam; Jalili-Firoozinezhad, Sasan; Rajabi-Zeleti, Sareh; Tafazzoli-Shadpour, Mohammad; Baharvand, Hossein; Aghdami, Nasser

    2016-06-01

    Injectable hydrogels that resemble electromechanical properties of the myocardium are crucial for cardiac tissue engineering prospects. We have developed a facile approach that uses chitosan (CS) to generate a thermosensitive conductive hydrogel with a highly porous network of interconnected pores. Gold nanoparticles (GNPs) were evenly dispersed throughout the CS matrix in order to provide electrical cues. The gelation response and electrical conductivity of the hydrogel were controlled by different concentrations of GNPs. The CS-GNP hydrogels were seeded with mesenchymal stem cells (MSCs) and cultivated for up to 14days in the absence of electrical stimulations. CS-GNP scaffolds supported viability, metabolism, migration and proliferation of MSCs along with the development of uniform cellular constructs. Immunohistochemistry for early and mature cardiac markers showed enhanced cardiomyogenic differentiation of MSCs within the CS-GNP compared to the CS matrix alone. The results of this study demonstrate that incorporation of nanoscale electro-conductive GNPs into CS hydrogels enhances the properties of myocardial constructs. These constructs could find utilization for regeneration of other electroactive tissues. PMID:27040204

  6. High-frequency ultrasound M-mode monitoring of HIFU ablation in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Kumon, R. E.; Gudur, M. S. R.; Zhou, Y.; Deng, C. X.

    2012-10-01

    Effective real-time HIFU lesion detection is important for expanded use of HIFU in interventional electrophysiology (e.g., epicardial ablation of cardiac arrhythmia). The goal of this study was to investigate rapid, high-frequency M-mode ultrasound imaging for monitoring spatiotemporal changes in tissue during HIFU application. The HIFU application (4.33 MHz, 1000 Hz PRF, 50% duty cycle, 1 s exposure, 6100 W/cm2) was perpendicularly applied to porcine cardiac tissue with a high-frequency imaging system (Visualsonics Vevo 770, 55 MHz, 4.5 mm focal distance) confocally aligned. Radiofrequency (RF) M-mode data (1 kHz PRF, 4 s × 7 mm) was acquired before, during, and after HIFU treatment. Gross lesions were compared with M-mode data to correlate lesion and cavity formation. Integrated backscatter, echo-decorrelation parameters, and their cumulative extrema over time were analyzed for automatically identifying lesion width and bubble formation. Cumulative maximum integrated backscatter showed the best results for identifying the final lesion width, and a criterion based on line-to-line decorrelation was proposed for identification of transient bubble activity.

  7. Direct Mechanical Stimulation of Stem Cells: A Beating Electromechanically Active Scaffold for Cardiac Tissue Engineering.

    PubMed

    Gelmi, Amy; Cieslar-Pobuda, Artur; de Muinck, Ebo; Los, Marek; Rafat, Mehrdad; Jager, Edwin W H

    2016-06-01

    The combination of stem cell therapy with a supportive scaffold is a promising approach to improving cardiac tissue engineering. Stem cell therapy can be used to repair nonfunctioning heart tissue and achieve myocardial regeneration, and scaffold materials can be utilized in order to successfully deliver and support stem cells in vivo. Current research describes passive scaffold materials; here an electroactive scaffold that provides electrical, mechanical, and topographical cues to induced human pluripotent stem cells (iPS) is presented. The poly(lactic-co-glycolic acid) fiber scaffold coated with conductive polymer polypyrrole (PPy) is capable of delivering direct electrical and mechanical stimulation to the iPS. The electroactive scaffolds demonstrate no cytotoxic effects on the iPS as well as an increased expression of cardiac markers for both stimulated and unstimulated protocols. This study demonstrates the first application of PPy as a supportive electroactive material for iPS and the first development of a fiber scaffold capable of dynamic mechanical actuation. PMID:27126086

  8. Imaging of action currents reveals the origin of biomagnetic fields in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Holzer, Jenny R.; Sidorov, Veniamin; Fong, Luis; Baudenbacher, Franz

    2003-03-01

    The origin of the magnetocardiogram (MCG) and the relative information content between the MCG and the electrocardiogram (ECG) remain central questions in biomagnetism. To provide key insights to this question, we mapped excitation wave fronts in a thin layer of cardiac tissue of an isolated rabbit heart using high-resolution LTS-SQUID microscopy and epi-fluorescent imaging with sub-millimeter resolution. The combination of the two methods allows us to map the transmembrane potential (Vm) and the magnetic field over the same area. The leading edge of a propagating action potential can be defined as the wave front and can be identified by the difference in relative intensities of resting and depolarized tissue in the epi-fluorescence data. The corresponding magnetic field pattern was used to calculate the net action current, which shows a strong current component parallel to and overlying the Vm wave front. These electrically silent currents are a direct consequence of the cardiac bidomain with unequal anisotropies in the intra- and extracellular space and depend strongly on the angle of the wave front relative to the fiber orientation. We provide evidence that the MCG contains information not present in the ECG, and that it is necessary to reexamine the modeling and interpretation of the MCG.

  9. Automated segmentation of cancer cell nuclei in complex tissue sections

    NASA Astrophysics Data System (ADS)

    Loukas, Constantinos G.; Wilson, George D.; Vojnovic, Borivoj

    2001-01-01

    Characterization of the proliferative activity of a tumor has been the subject of research for many years. The majority of the studies presented so far in the field of cytology and histology relates to the analysis of information from a limited number of cells, which are often easily distinguishable from the background and as well as from each other. The present paper introduces an automated image analysis technique for classification of cancer cell nuclei stained with proliferative markers. The images under processing were characterized by a high degree of complexity, containing considerable histological noise. The first step of the method aims to identify nuclear features of proliferating cells only, contained in large-scale histological images, using Principal Components Analysis (PCA). The histogram of the component that demonstrates the best contrast is processed appropriately for generating a binary image. Some standard morphological operations are then applied to remove any irrelevant structures and detect touching and/or overlapping nuclei. Two separate methods, Skeleton by Influence Zone and heuristic processing, are presented for segmentation of clustered cells. The algorithm was tested on tissue section images encountered in routine clinical practice with very encouraging results, after comparing image analysis and human observer cell counting.

  10. Influence of different fixation protocols on the preservation and dimensions of cardiac tissue.

    PubMed

    Hołda, Mateusz K; Klimek-Piotrowska, Wiesława; Koziej, Mateusz; Piątek, Katarzyna; Hołda, Jakub

    2016-08-01

    Recent extensive progress in invasive cardiac procedures has triggered a wave of dozens of heart morphometric anatomical studies that are carried out largely using autopsied samples fixed in formaldehyde solution prior to observations and measurements. In reality, very little is known about changes in heart tissue dimensions during fixation. The aim of this study was therefore to investigate how fixation affects the dimensions of cardiac tissue, and if different types and concentrations of reagents affect this phenomenon. A total of 40 pig heart samples were investigated, and seven different measuring sites were permanently marked in every heart prior to fixation. Four study groups (n = 10 each) were assembled that differed only in concentration and the type of fixative: (i) 2% formaldehyde solution; (ii) 4% formaldehyde solution (formalin); (iii) 10% formaldehyde solution; (iv) alcoholic formalin. The samples were measured before and after fixation at the following time points: 24 h, 72 h and 168 h. It was found that different fixatives significantly affected different parameters. Almost all of the heart dimensions that were measured stabilized after 24 h; later changes were statistically insignificant in the point-to-point comparison. Change in the length of the interatrial septum surface was not altered significantly in any of the fixatives after 24 h of preservation. It was found that 10% formaldehyde increased the thickness of muscular tissue only after 24 h; this thickening was reduced after 72 h and was insignificant at 168 h. Other heart parameters in this group do not present significant changes over the entire fixation time duration. In conclusion, the 10% formaldehyde phosphate-buffered solution appeared to be the best fixative among the fixatives that were studied for cardiac morphometric purposes; this solution caused the smallest changes in tissue dimensions. Measurements should be obtained at least after 1 week of preservation

  11. Characterization of electrospun polymer fibers for applications in cardiac tissue engineering and regenerative medicine

    NASA Astrophysics Data System (ADS)

    Rockwood, Danielle N.

    Electrospinning is a technique where a polymer solution is formed into a non-woven mat by electrically charging the solution as it leaves a capillary. The resulting mats have an interconnected porous network, and the system can be tailored in order to form aligned fibers. In this work, we have chosen to electrospin and characterize two polymers with unique properties with the intention to use them as scaffolds for cardiac tissue. The first polymer studied was poly(N-isopropyl acrylamide) (pNIPAM), a material which shows a thermoresponsive behavior around 32°C in aqueous solutions. In this work, pNIPAM was electrospun into fibrous mats from three solvents and the resulting electrospun mats were evaluated using DSC, polarized Raman, and infrared spectroscopy and compared to the bulk material. It was found that the electrospinning process did not alter the polymer and pNIPAM maintained its thermoresponsive behavior. Therefore, it is believed that electrospun pNIPAM mats could have the potential to be used as templates or filters in aqueous solutions at high temperatures, above 32°C, and then removed by lowering the temperature. The next polymer to be investigated was a biodegradable polyurethane (PU). The PU was electrospun into isotropic mats (ES-PU) and the material properties were evaluated via GPC, DSC, and Raman spectroscopy before and after processing. These analyses showed that the polymer was also unaffected by the electrospinning process. Additionally, the degradation profile of ES-PU in the presence of chymotrypsin was assessed. It was concluded that ES-PU mats show potential for use in soft tissue engineering applications. Therefore, the next step in this research was to investigate the ability of ES-PU mats to support cardiac cells and direct tissuegenesis. Cells isolated from immature cardiac ventricles were grown on ES-PU mats with either aligned or unaligned microfibers. ES-PU cultures contained electrically-coupled, contractile myocytes and it was

  12. Reentry produced by small-scale heterogeneities in a discrete model of cardiac tissue

    NASA Astrophysics Data System (ADS)

    Alonso, Sergio; Bär, Markus

    2016-06-01

    Reentries are reexcitations of cardiac tissue after the passing of an excitation wave which can cause dangerous arrhythmias like tachycardia or life-threatening heart failures like fibrillation. The heart is formed by a network of cells connected by gap junctions. Under ischemic conditions some of the cells lose their connections, because gap junctions are blocked and the excitability is decreased. We model a circular region of the tissue where a fraction of connections among individual cells are removed and substituted by non-conducting material in a two-dimensional (2D) discrete model of a heterogeneous excitable medium with local kinetics based on electrophysiology. Thus, two neighbouring cells are connected (disconnected) with a probability ϕ (1 – ϕ). Such a region is assumed to be surrounded by homogeneous tissue. The circular heterogeneous area is shown to act as a source of new waves which reenter into the tissue and reexcitate the whole domain. We employ the Fenton-Karma equations to model the action potential for the local kinetics of the discrete nodes to study the statistics of the reentries in two dimensional networks with different topologies. We conclude that the probability of reentry is determined by the proximity of the fraction of disrupted connections between neighboring nodes (“cells”) in the heterogeneous region to the percolation threshold.

  13. Electrospun PLGA fibers incorporated with functionalized biomolecules for cardiac tissue engineering.

    PubMed

    Yu, Jiashing; Lee, An-Rei; Lin, Wei-Han; Lin, Che-Wei; Wu, Yuan-Kun; Tsai, Wei-Bor

    2014-07-01

    Structural similarity of electrospun fibers (ESFs) to the native extracellular matrix provides great potential for the application of biofunctional ESFs in tissue engineering. This study aimed to synthesize biofunctionalized poly (L-lactide-co-glycolide) (PLGA) ESFs for investigating the potential for cardiac tissue engineering application. We developed a simple but novel strategy to incorporate adhesive peptides in PLGA ESFs. Two adhesive peptides derived from laminin, YIGSR, and RGD, were covalently conjugated to poly-L-lysine, and then mingled with PLGA solution for electrospinning. Peptides were uniformly distributed on the surface and in the interior of ESFs. PLGA ESFs incorporated with YIGSR or RGD or adsorbed with laminin significantly enhanced the adhesion of cardiomyocytes isolated from neonatal rats. Furthermore, the cells were found to adhere better on ESFs compared with flat substrates after 7 days of culture. Immunofluorescent staining of F-actin, vinculin, a-actinin, and N-cadherin indicated that cardiomyocytes adhered and formed striated α-actinin better on the laminin-coated ESFs and the YIGSR-incorporated ESFs compared with the RGD-incorporated ESFs. The expression of α-myosin heavy chain and β-tubulin on the YIGSR-incorporated ESFs was significantly higher compared with the expression level on PLGA and RGD-incorporated samples. Furthermore, the contraction of cardiomyocytes was faster and lasted longer on the laminin-coated ESFs and YIGSR-incorporated ESFs. The results suggest that aligned YIGSR-incorporated PLGA ESFs is a better candidate for the formation of cardiac patches. This study demonstrated the potential of using peptide-incorporated ESFs as designable-scaffold platform for tissue engineering. PMID:24471778

  14. Evaluation of an established pericardium patch for delivery of mesenchymal stem cells to cardiac tissue.

    PubMed

    Vashi, Aditya V; White, Jacinta F; McLean, Keith M; Neethling, William M L; Rhodes, David I; Ramshaw, John A M; Werkmeister, Jerome A

    2015-06-01

    The present study has evaluated a commercial pericardial material for its capacity to assist as a natural extracellular matrix (ECM) patch for the delivery and retention of mesenchymal stem cells for cardiac repair. The repair of cardiac tissue with cells delivered by an appropriate bioscaffold is expected to offer a superior, long-lasting treatment strategy. The present material, CardioCel®, is based on acellular pericardium that has been stabilized by treatments, including a low concentration of glutaraldehyde, that eliminate calcification after implantation. In the present study, we have assessed this material using human bone marrow mesenchymal stem cells at various cell densities under standard, static cell culture conditions. The initial seeding densities were monitored to evaluate the extent of cell attachment and cell viability, with subsequent cell proliferation assessed up to 4 weeks using an MTS assay. Cell morphology, infiltration, and spreading were tracked using scanning electron microscopy and phalloidin staining. The efficacy of long-term cell survival was further assessed by examining the extent and type of new tissue formation on seeded scaffolds at 70 days; both type I and type III collagens were present in fibrillar structures on these scaffolds indicating that the seeded stem cells had the capacity to differentiate into collagen-producing cells necessary to repair damaged ECM. These data show that the CardioCel® scaffold is an appropriate substrate for the stem cells and has the potential to both retain seeded stem cells and to act as a template for cell propagation and new tissue formation. PMID:25266083

  15. Evaluation of an established pericardium patch for delivery of mesenchymal stem cells to cardiac tissue.

    PubMed

    Vashi, Aditya V; White, Jacinta F; McLean, Keith M; Neethling, William M L; Rhodes, David I; Ramshaw, John A M; Werkmeister, Jerome A

    2014-09-25

    The present study has evaluated a commercial pericardial material for its capacity to assist as a natural extracellular matrix patch for the delivery and retention of mesenchymal stem cells for cardiac repair. The repair of cardiac tissue with cells delivered by an appropriate bioscaffold is expected to offer a superior, long-lasting treatment strategy. The present material, CardioCel®, is based on acellular pericardium that has been stabilized by treatments, including a low concentration of glutaraldehyde, that eliminate calcification after implantation. In the present study, we have assessed this material using human bone marrow mesenchymal stem cells at various cell densities under standard, static cell culture conditions. The initial seeding densities were monitored to evaluate the extent of cell attachment and cell viability, with subsequent cell proliferation assessed up to 4 weeks using an MTS assay. Cell morphology, infiltration and spreading were tracked using scanning electron microscopy and phalloidin staining. The efficacy of long-term cell survival was further assessed by examining the extent and type of new tissue formation on seeded scaffolds at 70 days; both type I and type III collagens were present in fibrillar structures on these scaffolds indicating that the seeded stem cells had the capacity to differentiate into collagen-producing cells necessary to repair damaged extracellular matrix. These data show that the CardioCel® scaffold is an appropriate substrate for the stem cells and has the potential to both retain seeded stem cells and to act as a template for cell propagation and new tissue formation. PMID:25256436

  16. Development and characterization of novel electrically conductive PANI-PGS composites for cardiac tissue engineering applications.

    PubMed

    Qazi, Taimoor H; Rai, Ranjana; Dippold, Dirk; Roether, Judith E; Schubert, Dirk W; Rosellini, Elisabetta; Barbani, Niccoletta; Boccaccini, Aldo R

    2014-06-01

    Cardiovascular diseases, especially myocardial infarction, are the leading cause of morbidity and mortality in the world, also resulting in huge economic burdens on national economies. A cardiac patch strategy aims at regenerating an infarcted heart by providing healthy functional cells to the injured region via a carrier substrate, and providing mechanical support, thereby preventing deleterious ventricular remodeling. In the present work, polyaniline (PANI) was doped with camphorsulfonic acid and blended with poly(glycerol-sebacate) at ratios of 10, 20 and 30vol.% PANI content to produce electrically conductive composite cardiac patches via the solvent casting method. The composites were characterized in terms of their electrical, mechanical and physicochemical properties. The in vitro biodegradability of the composites was also evaluated. Electrical conductivity increased from 0Scm(-1) for pure PGS to 0.018Scm(-1) for 30vol.% PANI-PGS samples. Moreover, the conductivities were preserved for at least 100h post fabrication. Tensile tests revealed an improvement in the elastic modulus, tensile strength and elasticity with increasing PANI content. The degradation products caused a local drop in pH, which was higher in all composite samples compared with pure PGS, hinting at a buffering effect due to the presence of PANI. Finally, the cytocompatibility of the composites was confirmed when C2C12 cells attached and proliferated on samples with varying PANI content. Furthermore, leaching of acid dopants from the developed composites did not have any deleterious effect on the viability of C2C12 cells. Taken together, these results confirm the potential of PANI-PGS composites for use as substrates to modulate cellular behavior via electrical stimulation, and as biocompatible scaffolds for cardiac tissue engineering applications. PMID:24561709

  17. Visualization of spiral and scroll waves in simulated and experimental cardiac tissue

    NASA Astrophysics Data System (ADS)

    Cherry, E. M.; Fenton, F. H.

    2008-12-01

    The heart is a nonlinear biological system that can exhibit complex electrical dynamics, complete with period-doubling bifurcations and spiral and scroll waves that can lead to fibrillatory states that compromise the heart's ability to contract and pump blood efficiently. Despite the importance of understanding the range of cardiac dynamics, studying how spiral and scroll waves can initiate, evolve, and be terminated is challenging because of the complicated electrophysiology and anatomy of the heart. Nevertheless, over the last two decades advances in experimental techniques have improved access to experimental data and have made it possible to visualize the electrical state of the heart in more detail than ever before. During the same time, progress in mathematical modeling and computational techniques has facilitated using simulations as a tool for investigating cardiac dynamics. In this paper, we present data from experimental and simulated cardiac tissue and discuss visualization techniques that facilitate understanding of the behavior of electrical spiral and scroll waves in the context of the heart. The paper contains many interactive media, including movies and interactive two- and three-dimensional Java appletsDisclaimer: IOP Publishing was not involved in the programming of this software and does not accept any responsibility for it. You download and run the software at your own risk. If you experience any problems with the software, please contact the author directly. To the fullest extent permitted by law, IOP Publishing Ltd accepts no responsibility for any loss, damage and/or other adverse effect on your computer system caused by your downloading and running this software. IOP Publishing Ltd accepts no responsibility for consequential loss..

  18. Tissue Plasminogen Activator Use in Cardiac Arrest Secondary to Fulminant Pulmonary Embolism

    PubMed Central

    Yousuf, Tariq; Brinton, Taylor; Ahmed, Khansa; Iskander, Joy; Woznicka, Daniel; Kramer, Jason; Kopiec, Adam; Chadaga, Amar R.; Ortiz, Kathia

    2016-01-01

    Background Tissue plasminogen activator (tPA) is used emergently to dissolve thrombi in the treatment of fulminant pulmonary embolism. Currently, there is a relative contraindication to tPA in the setting of traumatic or prolonged cardiopulmonary resuscitation > 10 minutes because of the risk of massive hemorrhage. Methods Our single-center, retrospective study investigated patients experiencing cardiac arrest (CA) secondary to pulmonary embolus. We compared the effectiveness of advanced cardiac life support with the administration of tPA vs. the standard of care consisting of advanced cardiac life support without thrombolysis. The primary endpoint was survival to discharge. Secondary endpoints were return of spontaneous circulation (ROSC), major bleeding, and minor bleeding. Results We analyzed 42 patients, of whom 19 received tPA during CA. Patients who received tPA were not associated with a statistically significant increase in survival to discharge (10.5% vs. 8.7%, P = 1.00) or ROSC (47.4% vs. 47.8%, P = 0.98) compared to the control group. We observed no statistically significant difference between the groups in major bleeding events (5.3% in the tPA group vs. 4.3% in the control group, P = 1.00) and minor bleeding events (10.5% in the tPA group vs. 0.0% in the control group, P = 0.11). Conclusion This study did not find a statistically significant difference in survival to discharge or in ROSC in patients treated with tPA during CA compared to patients treated with standard therapy. However, because no significant difference was found in major or minor bleeding, we suggest that the potential therapeutic benefits of this medication should not be limited by the potential for massive hemorrhage. Larger prospective studies are warranted to define the efficacy and safety profile of thrombolytic use in this population. PMID:26858790

  19. Myocyte-Depleted Engineered Cardiac Tissues Support Therapeutic Potential of Mesenchymal Stem Cells

    PubMed Central

    Serrao, Gregory W.; Turnbull, Irene C.; Ancukiewicz, Damian; Kim, Do Eun; Kao, Evan; Cashman, Timothy J.; Hadri, Lahouaria; Hajjar, Roger J.

    2012-01-01

    The therapeutic potential of mesenchymal stem cells (MSCs) for restoring cardiac function after cardiomyocyte loss remains controversial. Engineered cardiac tissues (ECTs) offer a simplified three-dimensional in vitro model system to evaluate stem cell therapies. We hypothesized that contractile properties of dysfunctional ECTs would be enhanced by MSC treatment. ECTs were created from neonatal rat cardiomyocytes with and without bone marrow-derived adult rat MSCs in a type-I collagen and Matrigel scaffold using custom elastomer molds with integrated cantilever force sensors. Three experimental groups included the following: (1) baseline condition ECT consisting only of myocytes, (2) 50% myocyte-depleted ECT, modeling a dysfunctional state, and (3) 50% myocyte-depleted ECT plus 10% MSC, modeling dysfunctional myocardium with intervention. Developed stress (DS) and pacing threshold voltage (VT) were measured using 2-Hz field stimulation at 37°C on culture days 5, 10, 15, and 20. By day 5, DS of myocyte-depleted ECTs was significantly lower than baseline, and VT was elevated. In MSC-supplemented ECTs, DS and VT were significantly better than myocyte-depleted values, approaching baseline ECTs. Findings were similar through culture day 15, but lost significance at day 20. Trends in DS were partly explained by changes in the cell number and alignment with time. Thus, supplementing myocyte-depleted ECTs with MSCs transiently improved contractile function and compensated for a 50% loss of cardiomyocytes, mimicking recent animal studies and clinical trials and supporting the potential of MSCs for myocardial therapy. PMID:22500611

  20. Strategies for the chemical and biological functionalization of scaffolds for cardiac tissue engineering: a review

    PubMed Central

    Tallawi, Marwa; Rosellini, Elisabetta; Barbani, Niccoletta; Cascone, Maria Grazia; Rai, Ranjana; Saint-Pierre, Guillaume; Boccaccini, Aldo R.

    2015-01-01

    The development of biomaterials for cardiac tissue engineering (CTE) is challenging, primarily owing to the requirement of achieving a surface with favourable characteristics that enhances cell attachment and maturation. The biomaterial surface plays a crucial role as it forms the interface between the scaffold (or cardiac patch) and the cells. In the field of CTE, synthetic polymers (polyglycerol sebacate, polyethylene glycol, polyglycolic acid, poly-l-lactide, polyvinyl alcohol, polycaprolactone, polyurethanes and poly(N-isopropylacrylamide)) have been proven to exhibit suitable biodegradable and mechanical properties. Despite the fact that they show the required biocompatible behaviour, most synthetic polymers exhibit poor cell attachment capability. These synthetic polymers are mostly hydrophobic and lack cell recognition sites, limiting their application. Therefore, biofunctionalization of these biomaterials to enhance cell attachment and cell material interaction is being widely investigated. There are numerous approaches for functionalizing a material, which can be classified as mechanical, physical, chemical and biological. In this review, recent studies reported in the literature to functionalize scaffolds in the context of CTE, are discussed. Surface, morphological, chemical and biological modifications are introduced and the results of novel promising strategies and techniques are discussed. PMID:26109634

  1. Strategies for the chemical and biological functionalization of scaffolds for cardiac tissue engineering: a review.

    PubMed

    Tallawi, Marwa; Rosellini, Elisabetta; Barbani, Niccoletta; Cascone, Maria Grazia; Rai, Ranjana; Saint-Pierre, Guillaume; Boccaccini, Aldo R

    2015-07-01

    The development of biomaterials for cardiac tissue engineering (CTE) is challenging, primarily owing to the requirement of achieving a surface with favourable characteristics that enhances cell attachment and maturation. The biomaterial surface plays a crucial role as it forms the interface between the scaffold (or cardiac patch) and the cells. In the field of CTE, synthetic polymers (polyglycerol sebacate, polyethylene glycol, polyglycolic acid, poly-l-lactide, polyvinyl alcohol, polycaprolactone, polyurethanes and poly(N-isopropylacrylamide)) have been proven to exhibit suitable biodegradable and mechanical properties. Despite the fact that they show the required biocompatible behaviour, most synthetic polymers exhibit poor cell attachment capability. These synthetic polymers are mostly hydrophobic and lack cell recognition sites, limiting their application. Therefore, biofunctionalization of these biomaterials to enhance cell attachment and cell material interaction is being widely investigated. There are numerous approaches for functionalizing a material, which can be classified as mechanical, physical, chemical and biological. In this review, recent studies reported in the literature to functionalize scaffolds in the context of CTE, are discussed. Surface, morphological, chemical and biological modifications are introduced and the results of novel promising strategies and techniques are discussed. PMID:26109634

  2. Three-dimensional pseudospectral modelling of cardiac propagation in an inhomogeneous anisotropic tissue.

    PubMed

    Ng, K T; Yan, R

    2003-11-01

    Various investigators have used the monodomain model to study cardiac propagation behaviour. In many cases, the governing non-linear parabolic equation is solved using the finite-difference method. An adequate discretisation of cardiac tissue with realistic dimensions, however, often leads to a large model size that is computationally demanding. Recently, it has been demonstrated, for a two-dimensional homogeneous monodomain, that the Chebyshev pseudospectral method can offer higher computational efficiency than the finite-difference technique. Here, an extension of the pseudospectral approach to a three-dimensional inhomogeneous case with fibre rotation is presented. The unknown transmembrane potential is expanded in terms of Chebyshev polynomial trial functions, and the monodomain equation is enforced at the Gauss-Lobatto node points. The forward Euler technique is used to advance the solution in time. Numerical results are presented that demonstrate that the Chebyshev pseudospectral method offered an even larger improvement in computational performance over the finite-difference method in the three-dimensional case. Specifically, the pseudospectral method allowed the number of nodes to be reduced by approximately 85 times, while the same solution accuracy was maintained. Depending on the model size, simulations were performed with approximately 18-41 times less memory and approximately 99-169 times less CPU time. PMID:14686586

  3. Myocyte-depleted engineered cardiac tissues support therapeutic potential of mesenchymal stem cells.

    PubMed

    Serrao, Gregory W; Turnbull, Irene C; Ancukiewicz, Damian; Kim, Do Eun; Kao, Evan; Cashman, Timothy J; Hadri, Lahouaria; Hajjar, Roger J; Costa, Kevin D

    2012-07-01

    The therapeutic potential of mesenchymal stem cells (MSCs) for restoring cardiac function after cardiomyocyte loss remains controversial. Engineered cardiac tissues (ECTs) offer a simplified three-dimensional in vitro model system to evaluate stem cell therapies. We hypothesized that contractile properties of dysfunctional ECTs would be enhanced by MSC treatment. ECTs were created from neonatal rat cardiomyocytes with and without bone marrow-derived adult rat MSCs in a type-I collagen and Matrigel scaffold using custom elastomer molds with integrated cantilever force sensors. Three experimental groups included the following: (1) baseline condition ECT consisting only of myocytes, (2) 50% myocyte-depleted ECT, modeling a dysfunctional state, and (3) 50% myocyte-depleted ECT plus 10% MSC, modeling dysfunctional myocardium with intervention. Developed stress (DS) and pacing threshold voltage (VT) were measured using 2-Hz field stimulation at 37°C on culture days 5, 10, 15, and 20. By day 5, DS of myocyte-depleted ECTs was significantly lower than baseline, and VT was elevated. In MSC-supplemented ECTs, DS and VT were significantly better than myocyte-depleted values, approaching baseline ECTs. Findings were similar through culture day 15, but lost significance at day 20. Trends in DS were partly explained by changes in the cell number and alignment with time. Thus, supplementing myocyte-depleted ECTs with MSCs transiently improved contractile function and compensated for a 50% loss of cardiomyocytes, mimicking recent animal studies and clinical trials and supporting the potential of MSCs for myocardial therapy. PMID:22500611

  4. Proteomic profiling of cardiac tissue by isolation of nuclei tagged in specific cell types (INTACT)

    PubMed Central

    Amin, Nirav M.; Greco, Todd M.; Kuchenbrod, Lauren M.; Rigney, Maggie M.; Chung, Mei-I; Wallingford, John B.; Cristea, Ileana M.; Conlon, Frank L.

    2014-01-01

    The proper dissection of the molecular mechanisms governing the specification and differentiation of specific cell types requires isolation of pure cell populations from heterogeneous tissues and whole organisms. Here, we describe a method for purification of nuclei from defined cell or tissue types in vertebrate embryos using INTACT (isolation of nuclei tagged in specific cell types). This method, previously developed in plants, flies and worms, utilizes in vivo tagging of the nuclear envelope with biotin and the subsequent affinity purification of the labeled nuclei. In this study we successfully purified nuclei of cardiac and skeletal muscle from Xenopus using this strategy. We went on to demonstrate the utility of this approach by coupling the INTACT approach with liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomic methodologies to profile proteins expressed in the nuclei of developing hearts. From these studies we have identified the Xenopus orthologs of 12 human proteins encoded by genes, which when mutated in human lead to congenital heart disease. Thus, by combining these technologies we are able to identify tissue-specific proteins that are expressed and required for normal vertebrate organ development. PMID:24496632

  5. Unstable spiral waves and local Euclidean symmetry in a model of cardiac tissue

    SciTech Connect

    Marcotte, Christopher D.; Grigoriev, Roman O.

    2015-06-15

    This paper investigates the properties of unstable single-spiral wave solutions arising in the Karma model of two-dimensional cardiac tissue. In particular, we discuss how such solutions can be computed numerically on domains of arbitrary shape and study how their stability, rotational frequency, and spatial drift depend on the size of the domain as well as the position of the spiral core with respect to the boundaries. We also discuss how the breaking of local Euclidean symmetry due to finite size effects as well as the spatial discretization of the model is reflected in the structure and dynamics of spiral waves. This analysis allows identification of a self-sustaining process responsible for maintaining the state of spiral chaos featuring multiple interacting spirals.

  6. [Clinical features and physical fitness parameters in athletes with cardiac connective tissue dysplasia syndrome].

    PubMed

    Mikhaĭlova, A V; Smolenskiĭ, A V

    2004-01-01

    Seventy-seven athletes with different manifestations of the cardiac connective tissue dysplasia (CCTD) syndrome (mitral prolapse (MP), anomalously located chordae (ALC) of the left ventricle and/or their combination) and 23 athletes without signs of CCTD syndrome were examined. The purpose of the study was to determine the specific features of the phenotypic picture, ECG data, and physical fitness in athletes with the manifestations of CCTD syndrome. The characteristic features of anthropometric data (higher heights and decreased body mass index), a larger number of the phenotypic signs of CCTD, the specific features of ECG, and lower parameters of physical fitness and aerobic capacities in the groups of MP, ALC, and/or their combination were identified; the impact of MP and ALC on these parameters was evaluated. PMID:15468725

  7. Covariant stringlike dynamics of scroll wave filaments in anisotropic cardiac tissue.

    PubMed

    Verschelde, Henri; Dierckx, Hans; Bernus, Olivier

    2007-10-19

    It has been hypothesized that stationary scroll wave filaments in cardiac tissue describe a geodesic in a curved space whose metric is the inverse diffusion tensor. Several numerical studies support this hypothesis, but no analytical proof has been provided yet for general anisotropy. In this Letter, we derive dynamic equations for the filament in the case of general anisotropy. These equations are covariant under general spatial coordinate transformations and describe the motion of a stringlike object in a curved space whose metric tensor is the inverse diffusion tensor. Therefore the behavior of scroll wave filaments in excitable media with anisotropy is similar to the one of cosmic strings in a curved universe. Our dynamic equations are valid for thin filaments and for general anisotropy. We show that stationary filaments obey the geodesic equation. PMID:17995301

  8. Vasovagal cardiac arrest during spinal anesthesia for Cesarean section -A case report-.

    PubMed

    Jang, Young-Eun; Do, Sang-Hwan; Song, In-Ae

    2013-01-01

    The vasovagal response is characterized by an inappropriate combination of bradycardia and paradoxical vasodilation. During a general or neuraxial anesthesia-induced sympathectomy, a sudden vagal activation and/or an acute reduction in sympathetic tone can cause serious vasovagal responses. Neuraxial anesthesia for Cesarean section may trigger vasovagal response, due to multiple risk factors; high neuraxial block, sudden hemorrhage, aortocarval compression, peritoneal manipulation, and emotional stress. A 39-year-old pregnant woman, at 38 weeks of gestation with episodes of non-sustained ventricular arrhythmia and newly developed vasovagal syncope during pregnancy, was scheduled to undergo a spinal anesthesia for an elective Cesarean section. Immediately after the placental expulsion, a sudden severe bradycardia, followed by a cardiac arrest occurred. The patient fully recovered after prompt cardiopulmonary resuscitation with chest compression, manual ventilation with oxygen, rapid injection of epinephrine and hydration. This case illustrates a serious potential risk of vasovagal response superimposed on neuraxial anesthesia, during a Cesarean section, especially during placental expulsion. PMID:23372892

  9. Tissue-Mimicking Geometrical Constraints Stimulate Tissue-Like Constitution and Activity of Mouse Neonatal and Human-Induced Pluripotent Stem Cell-Derived Cardiac Myocytes

    PubMed Central

    Pilarczyk, Götz; Raulf, Alexandra; Gunkel, Manuel; Fleischmann, Bernd K.; Lemor, Robert; Hausmann, Michael

    2016-01-01

    The present work addresses the question of to what extent a geometrical support acts as a physiological determining template in the setup of artificial cardiac tissue. Surface patterns with alternating concave to convex transitions of cell size dimensions were used to organize and orientate human-induced pluripotent stem cell (hIPSC)-derived cardiac myocytes and mouse neonatal cardiac myocytes. The shape of the cells, as well as the organization of the contractile apparatus recapitulates the anisotropic line pattern geometry being derived from tissue geometry motives. The intracellular organization of the contractile apparatus and the cell coupling via gap junctions of cell assemblies growing in a random or organized pattern were examined. Cell spatial and temporal coordinated excitation and contraction has been compared on plain and patterned substrates. While the α-actinin cytoskeletal organization is comparable to terminally-developed native ventricular tissue, connexin-43 expression does not recapitulate gap junction distribution of heart muscle tissue. However, coordinated contractions could be observed. The results of tissue-like cell ensemble organization open new insights into geometry-dependent cell organization, the cultivation of artificial heart tissue from stem cells and the anisotropy-dependent activity of therapeutic compounds. PMID:26751484

  10. Tissue-Mimicking Geometrical Constraints Stimulate Tissue-Like Constitution and Activity of Mouse Neonatal and Human-Induced Pluripotent Stem Cell-Derived Cardiac Myocytes.

    PubMed

    Pilarczyk, Götz; Raulf, Alexandra; Gunkel, Manuel; Fleischmann, Bernd K; Lemor, Robert; Hausmann, Michael

    2016-01-01

    The present work addresses the question of to what extent a geometrical support acts as a physiological determining template in the setup of artificial cardiac tissue. Surface patterns with alternating concave to convex transitions of cell size dimensions were used to organize and orientate human-induced pluripotent stem cell (hIPSC)-derived cardiac myocytes and mouse neonatal cardiac myocytes. The shape of the cells, as well as the organization of the contractile apparatus recapitulates the anisotropic line pattern geometry being derived from tissue geometry motives. The intracellular organization of the contractile apparatus and the cell coupling via gap junctions of cell assemblies growing in a random or organized pattern were examined. Cell spatial and temporal coordinated excitation and contraction has been compared on plain and patterned substrates. While the α-actinin cytoskeletal organization is comparable to terminally-developed native ventricular tissue, connexin-43 expression does not recapitulate gap junction distribution of heart muscle tissue. However, coordinated contractions could be observed. The results of tissue-like cell ensemble organization open new insights into geometry-dependent cell organization, the cultivation of artificial heart tissue from stem cells and the anisotropy-dependent activity of therapeutic compounds. PMID:26751484

  11. A Quantitative Comparison of the Behavior of Human Ventricular Cardiac Electrophysiology Models in Tissue

    PubMed Central

    Elshrif, Mohamed M.; Cherry, Elizabeth M.

    2014-01-01

    Numerical integration of mathematical models of heart cell electrophysiology provides an important computational tool for studying cardiac arrhythmias, but the abundance of available models complicates selecting an appropriate model. We study the behavior of two recently published models of human ventricular action potentials, the Grandi-Pasqualini-Bers (GPB) and the O'Hara-Virág-Varró-Rudy (OVVR) models, and compare the results with four previously published models and with available experimental and clinical data. We find the shapes and durations of action potentials and calcium transients differ between the GPB and OVVR models, as do the magnitudes and rate-dependent properties of transmembrane currents and the calcium transient. Differences also occur in the steady-state and S1–S2 action potential duration and conduction velocity restitution curves, including a maximum conduction velocity for the OVVR model roughly half that of the GPB model and well below clinical values. Between single cells and tissue, both models exhibit differences in properties, including maximum upstroke velocity, action potential amplitude, and minimum diastolic interval. Compared to experimental data, action potential durations for the GPB and OVVR models agree fairly well (although OVVR epicardial action potentials are shorter), but maximum slopes of steady-state restitution curves are smaller. Although studies show alternans in normal hearts, it occurs only in the OVVR model, and only for a narrow range of cycle lengths. We find initiated spiral waves do not progress to sustained breakup for either model. The dominant spiral wave period of the GPB model falls within clinically relevant values for ventricular tachycardia (VT), but for the OVVR model, the dominant period is longer than periods associated with VT. Our results should facilitate choosing a model to match properties of interest in human cardiac tissue and to replicate arrhythmia behavior more closely. Furthermore, by

  12. Design of Electrospun Hydrogel Fibers Containing Multivalent Peptide Conjugates for Cardiac Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Rode, Nikhil Ajit

    A novel material was designed using biomimetic engineering principles to recreate the chemical and physical environment of the extracellular matrix for cardiac tissue engineering applications. In order to control the chemical and specific bioactive signals provided by the material, a multivalent conjugate of a RGD-containing cell-binding peptide with hyaluronic acid was synthesized. These conjugates were characterized using in-line size exclusion chromatography with static multi-angle light scattering, UV absorbance, and differential refractive index measurements (SEC-MALS-UV-RI) to determine their molecular weight and valency, as well as the distributions of each. These conjugates were electrospun with poly(ethylene glycol) and poly(ethylene glycol) diacrylate to create a nanofibrous hydrogel material embedded with bioinstructive macromolecules. This electrospinning process was explored and optimized to create well-formed nanofibers. The diameter and orientation of the fibers was controlled to closely mimic the nanostructure of the extracellular matrix of the myocardium. Further characterization of the material was performed to ensure that its mechanical properties resemble those found in the myocardium. The availability of the peptides embedded in the hydrogel material was confirmed by measuring peptides released by trypsin incubation and was found to be sufficient to cause cell adhesion. This material was capable of supporting cell culture, maintaining the viability of cultured fibroblasts and cardiomyocytes, and preserving cardiomyocyte functionality. In this way, this material shows promise of serving as a biomimetic in vitro scaffold for generation of functional myocardial tissue, with possible applications as an in vivo cardiac patch for repair of the damage myocardium post-myocardial infarction.

  13. Epicardial Adipose Tissue Is Associated with Plaque Burden and Composition and Provides Incremental Value for the Prediction of Cardiac Outcome. A Clinical Cardiac Computed Tomography Angiography Study

    PubMed Central

    Gitsioudis, Gitsios; Schmahl, Christina; Missiou, Anna; Voss, Andreas; Schüssler, Alena; Abdel-Aty, Hassan; Buss, Sebastian J.; Mueller, Dirk; Vembar, Mani; Bryant, Mark; Kauczor, Hans-Ulrich; Giannitsis, Evangelos; Katus, Hugo A.; Korosoglou, Grigorios

    2016-01-01

    Objectives We sought to investigate the association of epicardial adipose tissue (eCAT) volume with plaque burden, circulating biomarkers and cardiac outcomes in patients with intermediate risk for coronary artery disease (CAD). Methods and Results 177 consecutive outpatients at intermediate risk for CAD and completed biomarker analysis including high-sensitive Troponin T (hs-TnT) and hs-CRP underwent 256-slice cardiac computed tomography angiography (CCTA) between June 2008 and October 2011. Patients with lumen narrowing ≥50% exhibited significantly higher eCAT volume than patients without any CAD or lumen narrowing <50% (median (interquartile range, IQR): 108 (73–167) cm3 vs. 119 (82–196) cm3, p = 0.04). Multivariate regression analysis demonstrated an independent association eCAT volume with plaque burden by number of lesions (R2 = 0.22, rpartial = 0.29, p = 0.026) and CAD severity by lumen narrowing (R2 = 0.22, rpartial = 0.23, p = 0.038) after adjustment for age, diabetes mellitus, hyperlidipemia, body-mass-index (BMI), hs-CRP and hs-TnT. Univariate Cox proportional hazards regression analysis identified a significant association for both increased eCAT volume and maximal lumen narrowing with all cardiac events. Multivariate Cox proportional hazards regression analysis revealed an independent association of increased eCAT volume with all cardiac events after adjustment for age, >3 risk factors, presence of CAD, hs-CRP and hs-TnT. Conclusion Epicardial adipose tissue volume is independently associated with plaque burden and maximum luminal narrowing by CCTA and may serve as an independent predictor for cardiac outcomes in patients at intermediate risk for CAD. PMID:27187590

  14. Modeling the response of normal and ischemic cardiac tissue to electrical stimulation

    NASA Astrophysics Data System (ADS)

    Kandel, Sunil Mani

    Heart disease, the leading cause of death worldwide, is often caused by ventricular fibrillation. A common treatment for this lethal arrhythmia is defibrillation: a strong electrical shock that resets the heart to its normal rhythm. To design better defibrillators, we need a better understanding of both fibrillation and defibrillation. Fundamental mysteries remain regarding the mechanism of how the heart responds to a shock, particularly anodal shocks and the resultant hyperpolarization. Virtual anodes play critical roles in defibrillation, and one cannot build better defibrillators until these mechanisms are understood. We are using mathematical modeling to numerically simulate observed phenomena, and are exploring fundamental mechanisms responsible for the heart's electrical behavior. Such simulations clarify mechanisms and identify key parameters. We investigate how systolic tissue responds to an anodal shock and how refractory tissue reacts to hyperpolarization by studying the dip in the anodal strength-interval curve. This dip is due to electrotonic interaction between regions of depolarization and hyperpolarization following a shock. The dominance of the electrotonic mechanism over calcium interactions implies the importance of the spatial distribution of virtual electrodes. We also investigate the response of localized ischemic tissue to an anodal shock by modeling a regional elevation of extracellular potassium concentration. This heterogeneity leads to action potential instability, 2:1 conduction block (alternans), and reflection-like reentry at the boarder of the normal and ischemic regions. This kind of reflection (reentry) occurs due to the delay between proximal and distal segments to re-excite the proximal segment. Our numerical simulations are based on the bidomain model, the state-of-the-art mathematical description of how cardiac tissue responds to shocks. The dynamic LuoRudy model describes the active properties of the membrane. To model ischemia

  15. No evidence for mosaic pathogenic copy number variations in cardiac tissue from patients with congenital heart malformations.

    PubMed

    Winberg, Johanna; Berggren, Håkan; Malm, Torsten; Johansson, Sune; Johansson Ramgren, Jens; Nilsson, Boris; Liedén, Agne; Nordenskjöld, Agneta; Gustavsson, Peter; Nordgren, Ann

    2015-03-01

    The aim of this study was to investigate if pathogenic copy number variations (CNVs) are present in mosaic form in patients with congenital heart malformations. We have collected cardiac tissue and blood samples from 23 patients with congenital heart malformations that underwent cardiac surgery and screened for mosaic gene dose alterations restricted to cardiac tissue using array comparative genomic hybridization (array CGH). We did not find evidence of CNVs in mosaic form after array CGH analysis. Pathogenic CNVs that were present in both cardiac tissue and blood were detected in 2/23 patients (9%), and in addition we found several constitutional CNVs of unclear clinical significance. This is the first study investigating mosaicism for CNVs in heart tissue compared to peripheral blood and the results do not indicate that pathogenic mosaic copy number changes are common in patients with heart malformations. Importantly, in line with previous studies, our results show that constitutional pathogenic CNVs are important factors contributing to congenital heart malformations. PMID:25652018

  16. Minimally invasive injectable short nanofibers of poly(glycerol sebacate) for cardiac tissue engineering.

    PubMed

    Ravichandran, Rajeswari; Venugopal, Jayarama Reddy; Sundarrajan, Subramanian; Mukherjee, Shayanti; Sridhar, Radhakrishnan; Ramakrishna, Seeram

    2012-09-28

    Myocardial tissue lacks the ability to appreciably regenerate itself following myocardial infarction (MI) which ultimately results in heart failure. Current therapies can only retard the progression of disease and hence tissue engineering strategies are required to facilitate the engineering of a suitable biomaterial to repair MI. The aim of this study was to investigate the in vitro properties of an injectable biomaterial for the regeneration of infarcted myocardium. Fabrication of core/shell fibers was by co-axial electrospinning, with poly(glycerol sebacate) (PGS) as core material and poly-L-lactic acid (PLLA) as shell material. The PLLA was removed by treatment of the PGS/PLLA core/shell fibers with DCM:hexane (2:1) to obtain PGS short fibers. These PGS short fibers offer the advantage of providing a minimally invasive injectable technique for the regeneration of infarcted myocardium. The scaffolds were characterized by SEM, FTIR and contact angle and cell-scaffold interactions using cardiomyocytes. The results showed that the cardiac marker proteins actinin, troponin, myosin heavy chain and connexin 43 were expressed more on short PGS fibers compared to PLLA nanofibers. We hypothesized that the injection of cells along with short PGS fibers would increase cell transplant retention and survival within the infarct, compared to the standard cell injection system. PMID:22947662

  17. Minimally invasive injectable short nanofibers of poly(glycerol sebacate) for cardiac tissue engineering

    NASA Astrophysics Data System (ADS)

    Ravichandran, Rajeswari; Reddy Venugopal, Jayarama; Sundarrajan, Subramanian; Mukherjee, Shayanti; Sridhar, Radhakrishnan; Ramakrishna, Seeram

    2012-09-01

    Myocardial tissue lacks the ability to appreciably regenerate itself following myocardial infarction (MI) which ultimately results in heart failure. Current therapies can only retard the progression of disease and hence tissue engineering strategies are required to facilitate the engineering of a suitable biomaterial to repair MI. The aim of this study was to investigate the in vitro properties of an injectable biomaterial for the regeneration of infarcted myocardium. Fabrication of core/shell fibers was by co-axial electrospinning, with poly(glycerol sebacate) (PGS) as core material and poly-l-lactic acid (PLLA) as shell material. The PLLA was removed by treatment of the PGS/PLLA core/shell fibers with DCM:hexane (2:1) to obtain PGS short fibers. These PGS short fibers offer the advantage of providing a minimally invasive injectable technique for the regeneration of infarcted myocardium. The scaffolds were characterized by SEM, FTIR and contact angle and cell-scaffold interactions using cardiomyocytes. The results showed that the cardiac marker proteins actinin, troponin, myosin heavy chain and connexin 43 were expressed more on short PGS fibers compared to PLLA nanofibers. We hypothesized that the injection of cells along with short PGS fibers would increase cell transplant retention and survival within the infarct, compared to the standard cell injection system.

  18. Alginate-polyester comacromer based hydrogels as physiochemically and biologically favorable entities for cardiac tissue engineering.

    PubMed

    Thankam, Finosh G; Muthu, Jayabalan

    2015-11-01

    The physiochemical and biological responses of tissue engineering hydrogels are crucial in determining their desired performance. A hybrid comacromer was synthesized by copolymerizing alginate and poly(mannitol fumarate-co-sebacate) (pFMSA). Three bimodal hydrogels pFMSA-AA, pFMSA-MA and pFMSA-NMBA were synthesized by crosslinking with Ca(2+) and vinyl monomers acrylic acid (AA), methacrylic acid (MA) and N,N'-methylene bisacrylamide (NMBA), respectively. Though all the hydrogels were cytocompatible and exhibited a normal cell cycle profile, pFMSA-AA exhibited superior physiochemical properties viz non-freezable water content (58.34%) and water absorption per unit mass (0.97 g water/g gel) and pore length (19.92±3.91 μm) in comparing with other two hydrogels. The increased non-freezable water content and water absorption of pFMSA-AA hydrogels greatly influenced its biological performance, which was evident from long-term viability assay and cell cycle proliferation. The physiochemical and biological favorability of pFMSA-AA hydrogels signifies its suitability for cardiac tissue engineering. PMID:26151567

  19. Modelling the effect of gap junctions on tissue-level cardiac electrophysiology.

    PubMed

    Bruce, Doug; Pathmanathan, Pras; Whiteley, Jonathan P

    2014-02-01

    When modelling tissue-level cardiac electrophysiology, a continuum approximation to the discrete cell-level equations, known as the bidomain equations, is often used to maintain computational tractability. Analysing the derivation of the bidomain equations allows us to investigate how microstructure, in particular gap junctions that electrically connect cells, affect tissue-level conductivity properties. Using a one-dimensional cable model, we derive a modified form of the bidomain equations that take gap junctions into account, and compare results of simulations using both the discrete and continuum models, finding that the underlying conduction velocity of the action potential ceases to match up between models when gap junctions are introduced at physiologically realistic coupling levels. We show that this effect is magnified by: (i) modelling gap junctions with reduced conductivity; (ii) increasing the conductance of the fast sodium channel; and (iii) an increase in myocyte length. From this, we conclude that the conduction velocity arising from the bidomain equations may not be an accurate representation of the underlying discrete system. In particular, the bidomain equations are less likely to be valid when modelling certain diseased states whose symptoms include a reduction in gap junction coupling or an increase in myocyte length. PMID:24338526

  20. Multiphoton microscopy using intrinsic signals for pharmacological studies in unstained cardiac and vascular tissue

    NASA Astrophysics Data System (ADS)

    Beaurepaire, Emmanuel; Boulesteix, Thierry; Pena, Ana-Maria; Pages, Nicole; Senni, Karim; Godeau, Gaston; Sauviat, Martin-Pierre; Schanne-Klein, Marie-Claire

    2005-03-01

    We report two novel applications of multiphoton microscopy for pharmacological studies of unstained cardiovascular tissue. First, we show that second harmonic generation (SHG) microscopy of unstained cardiac myocytes can be used to determine the sarcomere length with sub-resolution accuracy, owing to the remarkable contrast of the SHG signal originating from myosin filaments. A measurement precision of 20 nm is achieved, taking the sample variability into account. We used this technique to measure sarcomere contracture in the presence of saxitoxin, and results were in agreement with mechanical measurements of atrial tissue contracture. Second, we characterized multiphoton microscopy of intact unlabeled arteries. We performed simultaneous detection of two-photon-excited fluorescence (2PEF) from elastin laminae and SHG from collagen fibers upon 860 nm excitation. Combined 2PEF/SHG images provide a highly specific, micron scale description of the architecture of these two major components of the vessel wall. We used this methodology to study the effects of lindane (a pesticide) on the artery wall structure and evidenced structural alteration of the vessel morphology.

  1. Development and Implementation of Discrete Polymeric Microstructural Cues for Applications in Cardiac Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Pinney, James Richardson

    Chronic fibrosis caused by acute myocardial infarction (MI) leads to increased morbidity and mortality due to cardiac dysfunction. Despite care in the acute setting of MI, subsequent development of scar tissue and a lack of treatments for this maladaptive response lead to a poor prognosis. This has increased burdens on the cost of healthcare due to chronic disability. Here a novel therapeutic strategy that aims to mitigate myocardial fibrosis by utilizing injectable polymeric microstructural cues to attenuate the fibrotic response and improve functional outcomes is presented. Additionally, applications of integrated chemical functionalizations into discrete, micro-scale polymer structures are discussed in the realm of tissue engineering in order to impart enhancements in in vivo localization, three-dimensional manipulation and drug delivery. Polymeric microstructures, termed "microrods" and "microcubes", were fabricated using photolithographic techniques and studied in three-dimensional culture models of the fibrotic environment and by direct injection into the infarct zone of adult Sprague-Dawley rats. In vitro gene expression and functional and histological results were analyzed, showing a dose-dependent down-regulation fibrotic indicators and improvement in cardiac function. Furthermore, iron oxide nanoparticles and functionalized fluorocarbons were incorporated into the polymeric microdevices to promote in situ visualization by magnetic resonance imaging as well as to facilitate the manipulation and alignment of microstructural cues in a tissue-realistic environment. Lastly, successful encapsulation of native MGF peptide within microrods is demonstrated with release over two weeks as a proof of concept in the ability to locally deliver myogenic or supportive pharmacotherapeutics to the injured myocardium. This work demonstrates the efficacy and versatility of discrete microtopographical cues to attenuate the fibrotic response after MI and suggests a novel

  2. Nitric oxide mediates cardiac protection of tissue kallikrein by reducing inflammation and ventricular remodeling after myocardial ischemia/reperfusion

    PubMed Central

    Yin, Hang; Chao, Lee; Chao, Julie

    2008-01-01

    We assessed the role of nitric oxide (NO) and the kinin B2 receptor in mediating tissue kallikrein’s actions in intramyocardial inflammation and cardiac remodeling after ischemia/reperfusion (I/R) injury. Adenovirus carrying the human tissue kallikrein gene was delivered locally into rat hearts 4 days prior to 30-minute ischemia followed by 24- hour or 7-day reperfusion with or without administration of icatibant, a kinin B2 receptor antagonist, or N(ω)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor. Kallikrein gene delivery improved cardiac contractility and diastolic function, reduced infarct size at 1 day after I/R without affecting mean arterial pressure. Kallikrein treatment reduced macrophage/monocyte and neutrophil accumulation in the infarcted myocardium in association with reduced intercellular adhesion molecule-1 levels. Kallikrein increased cardiac endothelial nitric oxide synthase phosphorylation and NO levels and decreased superoxide formation, TGF-β1 levels and Smad2 phosphorylation. Furthermore, kallikrein reduced I/R-induced JNK, p38MAPK, IκB-α phosphorylation and nuclear NF-κB activation. In addition, kallikrein improved cardiac performance, reduced infarct size and prevented ventricular wall thinning at 7 days after I/R. The effects of kallikrein on cardiac function, inflammation and signaling mediators were all blocked by icatibant and L-NAME. These results indicate that tissue kallikrein through kinin B2 receptor and NO formation improves cardiac function, prevents inflammation and limits left ventricular remodeling after myocardial I/R by suppression of oxidative stress, TGF-β1/Smad2 and JNK/p38MAPK signaling pathways and NF-κB activation. PMID:18068196

  3. Adult stem cells and biocompatible scaffolds as smart drug delivery tools for cardiac tissue repair.

    PubMed

    Pagliari, Stefania; Romanazzo, Sara; Mosqueira, Diogo; Pinto-do-Ó, Perpetua; Aoyagi, Takao; Forte, Giancarlo

    2013-01-01

    The contribution of adult stem cells to cardiac repair is mostly ascribed to an indirect paracrine effect, rather than to their actual engraftment and differentiation into new contractile and vascular cells. This effect consists in a direct reduction of host cell death, promotion of neovascularization, and in a "bystander effect" on local inflammation. A number of cytokines secreted by adult stem/progenitor cells has been proposed to be responsible for the consistent beneficial effect reported in the early attempts to deliver different stem cell subsets to the injured myocardium. Aiming to maximize their beneficial activity on the diseased myocardium, the genetic modification of adult stem cells to enhance and/or control the secretion of specific cytokines would turn them into active drug delivery vectors. On the other hand, engineering biocompatible scaffolds as to release paracrine factors could result in multiple advantages: (1) achieve a local controlled release of the drug of interest, thus minimizing off-target effects, (2) enhance stem cell retention in the injured area and (3) boost the beneficial paracrine effects exerted by adult stem cells on the host tissue. In the present review, a critical overview of the state-of-the-art in the modification of stem cells and the functionalization of biocompatible scaffolds to deliver beneficial soluble factors to the injured myocardium is offered. Besides the number of concerns to be addressed before a clinical application can be foreseen for such concepts, this path could translate into the generation of active scaffolds as smart cell and drug delivery systems for cardiac repair. PMID:23745554

  4. Expansion and Characterization of Neonatal Cardiac Pericytes Provides a Novel Cellular Option for Tissue Engineering in Congenital Heart Disease

    PubMed Central

    Avolio, Elisa; Rodriguez-Arabaolaza, Iker; Spencer, Helen L; Riu, Federica; Mangialardi, Giuseppe; Slater, Sadie C; Rowlinson, Jonathan; Alvino, Valeria V; Idowu, Oluwasomidotun O; Soyombo, Stephanie; Oikawa, Atsuhiko; Swim, Megan M; Kong, Cherrie H T; Cheng, Hongwei; Jia, Huidong; Ghorbel, Mohamed T; Hancox, Jules C; Orchard, Clive H; Angelini, Gianni; Emanueli, Costanza; Caputo, Massimo; Madeddu, Paolo

    2015-01-01

    Background Living grafts produced by combining autologous heart-resident stem/progenitor cells and tissue engineering could provide a new therapeutic option for definitive correction of congenital heart disease. The aim of the study was to investigate the antigenic profile, expansion/differentiation capacity, paracrine activity, and pro-angiogenic potential of cardiac pericytes and to assess their engrafting capacity in clinically certified prosthetic grafts. Methods and Results CD34pos cells, negative for the endothelial markers CD31 and CD146, were identified by immunohistochemistry in cardiac leftovers from infants and children undergoing palliative repair of congenital cardiac defects. Following isolation by immunomagnetic bead-sorting and culture on plastic in EGM-2 medium supplemented with growth factors and serum, CD34pos/CD31neg cells gave rise to a clonogenic, highly proliferative (>20 million at P5), spindle-shape cell population. The following populations were shown to expresses pericyte/mesenchymal and stemness markers. After exposure to differentiation media, the expanded cardiac pericytes acquired markers of vascular smooth muscle cells, but failed to differentiate into endothelial cells or cardiomyocytes. However, in Matrigel, cardiac pericytes form networks and enhance the network capacity of endothelial cells. Moreover, they produce collagen-1 and release chemo-attractants that stimulate the migration of c-Kitpos cardiac stem cells. Cardiac pericytes were then seeded onto clinically approved xenograft scaffolds and cultured in a bioreactor. After 3 weeks, fluorescent microscopy showed that cardiac pericytes had penetrated into and colonized the graft. Conclusions These findings open new avenues for cellular functionalization of prosthetic grafts to be applied in reconstructive surgery of congenital heart disease. PMID:26080813

  5. Evaluation of cardiac functions of cirrhotic children using serum brain natriuretic peptide and tissue Doppler imaging

    PubMed Central

    Fattouh, Aya M; El-Shabrawi, Mortada H; Mahmoud, Enas H; Ahmed, Wafaa O

    2016-01-01

    Background: Cirrhotic cardiomyopathy (CCM) is described as the presence of cardiac dysfunction in cirrhotic patients. In children with chronic liver disease, CCM has been very rarely investigated. The Aim of the Study: Is to evaluate the cardiac function of cirrhotic children to identify those with CCM. Patients and Methods: Fifty-two cirrhotic patients and 53 age and sex matched controls were assessed using serum brain-type natriuretic peptide (BNP), conventional echocardiography, and tissue Doppler imaging. Results: Patients’ mean ages were 7.66 ± 4.16 years (vs. 6.88 ± 3.04 years for the controls). The study included 27 males and 25 females (28 and 25 respectively for the controls). Patients had larger left atrium and right ventricle (RV) (P value 0.05) and increased LV posterior wall thickness than controls (P value 0.04). They had higher late atrial diastolic filling velocity (A) of tricuspid valve (TV) inflow (0.59 ± 0.17 vs. 0.5 ± 0.1 m/s, P < 0.001) and lower ratios between the early diastolic filling velocity (E) and A wave velocity (E/A) of both mitral valve and TV inflow (1.7 ± 0.35 vs. 1.87 ± 0.34 and 1.3 ± 0.3 vs. 1.5 ± 0.3, P < 0.005 and 0.0008, respectively). Patients had significantly longer isovolumic relaxation time of LV (45.5 ± 11.1 vs. 40.5 ± 7.7 ms P 0.008), higher late diastolic peak myocardial velocity (A’) (11.8 ± 3.6 vs. 9.5 ± 2.7 ms, P 0.0003) and systolic velocity (S’) of the RV (14.5 ± 2.7 vs. 13.2 ± 2.9, P 0.01) and significantly higher myocardial performance index of both LV and RV (P 0.001 and 0.01). BNP levels were significantly higher in cases than controls (5.25 ng/l vs. 3.75 ng/l, P < 0.04) and was correlated with the E wave velocity of the TV (r 0.004) and the E/E’ ratio of the RV (r 0.001). None of the clinical or laboratory data were correlated with the BNP level. Conclusion Cirrhotic children have cardiac dysfunction mainly in the form of diastolic dysfunction. There is a need that CCM be more accurately

  6. Teratocarcinomas Arising from Allogeneic Induced Pluripotent Stem Cell-Derived Cardiac Tissue Constructs Provoked Host Immune Rejection in Mice

    PubMed Central

    Kawamura, Ai; Miyagawa, Shigeru; Fukushima, Satsuki; Kawamura, Takuji; Kashiyama, Noriyuki; Ito, Emiko; Watabe, Tadashi; Masuda, Shigeo; Toda, Koichi; Hatazawa, Jun; Morii, Eiichi; Sawa, Yoshiki

    2016-01-01

    Transplantation of induced pluripotent stem cell-derived cardiac tissue constructs is a promising regenerative treatment for cardiac failure: however, its tumourigenic potential is concerning. We hypothesised that the tumourigenic potential may be eliminated by the host immune response after allogeneic cell transplantation. Scaffold-free iPSC-derived cardaic tissue sheets of C57BL/6 mouse origin were transplanted into the cardiac surface of syngeneic C57BL/6 mice and allogeneic BALB/c mice with or without tacrolimus injection. Syngeneic mice and tacrolimus-injected immunosuppressed allogeneic mice formed teratocarcinomas with identical phenotypes, characteristic, and time courses, as assessed by imaging tools including 18F-fluorodeoxyglucose-positron emission tomography. In contrast, temporarily immunosuppressed allogeneic mice, following cessation of tacrolimus injection displayed diminished progression of the teratocarcinoma, accompanied by an accumulation of CD4/CD8-positive T cells, and finally achieved complete elimination of the teratocarcinoma. Our results indicated that malignant teratocarcinomas arising from induced pluripotent stem cell-derived cardiac tissue constructs provoked T cell-related host immune rejection to arrest tumour growth in murine allogeneic transplantation models. PMID:26763872

  7. Nonequilibrium Arrhythmic States and Transitions in a Mathematical Model for Diffuse Fibrosis in Human Cardiac Tissue

    PubMed Central

    Majumder, Rupamanjari; Nayak, Alok Ranjan; Pandit, Rahul

    2012-01-01

    We present a comprehensive numerical study of spiral-and scroll-wave dynamics in a state-of-the-art mathematical model for human ventricular tissue with fiber rotation, transmural heterogeneity, myocytes, and fibroblasts. Our mathematical model introduces fibroblasts randomly, to mimic diffuse fibrosis, in the ten Tusscher-Noble-Noble-Panfilov (TNNP) model for human ventricular tissue; the passive fibroblasts in our model do not exhibit an action potential in the absence of coupling with myocytes; and we allow for a coupling between nearby myocytes and fibroblasts. Our study of a single myocyte-fibroblast (MF) composite, with a single myocyte coupled to fibroblasts via a gap-junctional conductance , reveals five qualitatively different responses for this composite. Our investigations of two-dimensional domains with a random distribution of fibroblasts in a myocyte background reveal that, as the percentage of fibroblasts increases, the conduction velocity of a plane wave decreases until there is conduction failure. If we consider spiral-wave dynamics in such a medium we find, in two dimensions, a variety of nonequilibrium states, temporally periodic, quasiperiodic, chaotic, and quiescent, and an intricate sequence of transitions between them; we also study the analogous sequence of transitions for three-dimensional scroll waves in a three-dimensional version of our mathematical model that includes both fiber rotation and transmural heterogeneity. We thus elucidate random-fibrosis-induced nonequilibrium transitions, which lead to conduction block for spiral waves in two dimensions and scroll waves in three dimensions. We explore possible experimental implications of our mathematical and numerical studies for plane-, spiral-, and scroll-wave dynamics in cardiac tissue with fibrosis. PMID:23071505

  8. The Effects of Radiofrequency or Cryothermal Ablation on Biomechanical Properties of Isolated Human or Swine Cardiac Tissues

    PubMed Central

    Quallich, Stephen G.; Kriege, Kevin E.

    2016-01-01

    Changes in cardiac tissue properties following the application of various ablation modalities may lead to the development of an array of associated complications. The application of either radio frequency (RF) or cryothermal ablations will alter the biomechanical properties of various cardiac tissues in a differential manner; in some cases, this may be attributable to increased incidences of cardiac tamponade, pulmonary vein stenosis, and/or atrial-esophageal fistula. Thus, a greater understanding of the underlying changes in tissue properties induced by ablative therapies will ultimately promote safer and more efficacious procedures. The effects of applied RF or cryothermal energies on the biomechanical properties of the pulmonary vein, left atrial, or right atrial samples (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\text {n}=369$ \\end{document}) were examined from fresh excised porcine (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\text {n}=35$ \\end{document}) and donated human tissue (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\text {n}=11$ \\end{document}). RF ablations were found to reduce the tensile strength of the porcine cardiac specimens (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt

  9. Detection of Papillomavirus Gene Expression Patterns in Tissue Sections.

    PubMed

    Griffin, Heather; Doorbar, John

    2016-01-01

    Molecular events during the papillomavirus life cycle can be mapped in infected tissue biopsies using antibodies to viral and cellular gene products, or by in situ hybridization approaches that detect viral DNA or viral transcription products. For proteins, ease of immunodetection depends on antibody specificity and antigen availability. Epitopes in formalin-fixed paraffin-embedded (FFPE) samples are often masked by crosslinking and must be exposed for immunodetection. RNA in FFPE material is often degraded, and such tissue must be handled carefully to optimize detection. Viral proteins and viral genomic DNA are both well preserved in routinely processed FFPE samples, with sensitive detection methodologies allowing the simultaneous detection of multiple markers. The combined visualization of nucleic acid and (viral) protein targets, when coupled with image analysis approaches that allow correlation with standard pathology diagnosis, have allowed us to understand the molecular changes required for normal HPV life-cycle organization as well as deregulation during cancer progression. © 2016 by John Wiley & Sons, Inc. PMID:27153382

  10. Application of perfluorocarbon emulsions as fluorine-19 nuclear magnetic resonance molecular probes of cardiac tissues oxygen tension

    SciTech Connect

    Shukla, H.P.

    1994-01-01

    The basic and universal need for oxygen in mammalian tissue has long been recognized. The quantitation of oxygen tension (pO[sub 2]) in cardiac tissue is available by many techniques, but these are generally invasive or superficial. In addition, the role of cardiac pO[sub 2] along the oxygen gradient has yet to be defined. To date, no single method fits the ideal, i.e. non-invasive, sensitive, accurate, rapid, three-dimensional, and economical. The use of perfluorocarbon emulsions as tissue oximeters by [sup 19]F NMR relaxometry has the potential to fulfill many of these requirements. Development of a novel method requires the assessment of validity, reproducibility, and practicality. To this end, I have characterized the linear relationship between pO[sub 2] and the [sup 19]F spin-lattice relaxation rate (R1) for several perfluorocarbon (PFC) emulsions at high magnetic fields. The physical basis of underlying [sup 19]F relaxation mechanisms were modeled with respect to the structure and thermal behavior of perfluorocarbon molecules. Utility of these molecules in vivo was tested by spectroscopy and imaging of perfluorocarbons sequestered in the perfused rat heart. Under a wide range of steady-state oxygenation, the global cardiac tissue pO[sub 2] of perfused rat hearts responded in a manner consistent with physiological processes. The cardiac pO[sub 2] was measured by MRS either with high reproducibility ([plus minus]20 torr) or temporal resolution (1 sec). Independent validation of this method was provided in the total absence of oxygen consumption by the heart. Localized pO[sub 2] measurements in tissue were accomplished by [sup 19]F MRI of PFCs in arrested, perfused rat hearts, and found to change significantly with ischemia. It was concluded that the measurement of pO[sub 2] by NMR can provide important information about the physiological condition of the heart.

  11. Direct imaging of elemental distributions in tissue sections by laser ablation mass spectrometry.

    PubMed

    Shariatgorji, Mohammadreza; Nilsson, Anna; Bonta, Maximilian; Gan, Jinrui; Marklund, Niklas; Clausen, Fredrik; Källback, Patrik; Loden, Henrik; Limbeck, Andreas; Andrén, Per E

    2016-07-15

    We present a strategy for imaging of elements in biological tissues using laser ablation (LA) mass spectrometry (MS), which was compared to laser ablation inductively coupled plasma (LA-ICP) MS. Both methods were adopted for quantitative imaging of elements in mouse kidney, as well as traumatic brain injury model tissue sections. MS imaging (MSI) employing LA provides quantitative data by comparing signal abundances of sodium from tissues to those obtained by imaging quantitation calibration standards of the target element applied to adjacent control tissue sections. LA-ICP MSI provided quantitative data for several essential elements in both brain and kidney tissue sections using a dried-droplet approach. Both methods were used to image a rat model of traumatic brain injury, revealing accumulations of sodium and calcium in the impact area and its peripheral regions. LA MSI is shown to be a viable option for quantitative imaging of specific elements in biological tissue sections. PMID:27263025

  12. Efficient integration of a realistic two-dimensional cardiac tissue model by domain decomposition.

    PubMed

    Quan, W; Evans, S J; Hastings, H M

    1998-03-01

    The size of realistic cardiac tissue models has been limited by their high computational demands. In particular, the Luo-Rudy phase II membrane model, used to simulate a thin sheet of ventricular tissue with arrays of coupled ventricular myocytes, is usually limited to 100 x 100 arrays. We introduce a new numerical method based on domain decomposition and a priority queue integration scheme which reduces the computational cost by a factor of 3-17. In the standard algorithm all the nodes advance with the same time step delta t, whose size is limited by the time scale of activation. However, at any given time, many regions may be inactive and do not require the same small delta t and consequent extensive computations. Hence, adjusting delta t locally is a key factor in improving computational efficiency, since most of the computing time is spent calculating ionic currents. This paper proposes an efficient adaptive numerical scheme for integrating a two-dimensional (2-D) propagation model, by incorporating local adjustments of delta t. In this method, alternating direction Cooley-Dodge and Rush-Larsen methods were used for numerical integration. Between consecutive integrations over the whole domain using an implicit method, the model was spatially decomposed into many subdomains, and delta t adjusted locally. The Euler method was used for numerical integration in the subdomains. Local boundary values were determined from the boundary mesh elements of the neighboring subdomains using linear interpolation. Because delta t was defined locally, a priority queue was used to store and order next update times for each subdomain. The subdomain with the earliest update time was given the highest priority and advanced first. This new method yielded stable solutions with relative errors less than 1% and reduced computation time by a factor of 3-17 and will allow much larger (e.g., 500 x 500) models based on realistic membrane kinetics and realistic dimensions to simulate

  13. Differentially expressed genes in embryonic cardiac tissues of mice lacking Folr1 gene activity

    PubMed Central

    Zhu, Huiping; Cabrera, Robert M; Wlodarczyk, Bogdan J; Bozinov, Daniel; Wang, Deli; Schwartz, Robert J; Finnell, Richard H

    2007-01-01

    Background Heart anomalies are the most frequently observed among all human congenital defects. As with the situation for neural tube defects (NTDs), it has been demonstrated that women who use multivitamins containing folic acid peri-conceptionally have a reduced risk for delivering offspring with conotruncal heart defects [1-3]. Cellular folate transport is mediated by a receptor or binding protein and by an anionic transporter protein system. Defective function of the Folr1 (also known as Folbp1; homologue of human FRα) gene in mice results in inadequate transport, accumulation, or metabolism of folate during cardiovascular morphogenesis. Results We have observed cardiovascular abnormalities including outflow tract and aortic arch arterial defects in genetically compromised Folr1 knockout mice. In order to investigate the molecular mechanisms underlying the failure to complete development of outflow tract and aortic arch arteries in the Folr1 knockout mouse model, we examined tissue-specific gene expression difference between Folr1 nullizygous embryos and morphologically normal heterozygous embryos during early cardiac development (14-somite stage), heart tube looping (28-somite stage), and outflow track septation (38-somite stage). Microarray analysis was performed as a primary screening, followed by investigation using quantitative real-time PCR assays. Gene ontology analysis highlighted the following ontology groups: cell migration, cell motility and localization of cells, structural constituent of cytoskeleton, cell-cell adhesion, oxidoreductase, protein folding and mRNA processing. This study provided preliminary data and suggested potential candidate genes for further description and investigation. Conclusion The results suggested that Folr1 gene ablation and abnormal folate homeostasis altered gene expression in developing heart and conotruncal tissues. These changes affected normal cytoskeleton structures, cell migration and motility as well as cellular

  14. Exact coherent structures and chaotic dynamics in a model of cardiac tissue.

    PubMed

    Byrne, Greg; Marcotte, Christopher D; Grigoriev, Roman O

    2015-03-01

    Unstable nonchaotic solutions embedded in the chaotic attractor can provide significant new insight into chaotic dynamics of both low- and high-dimensional systems. In particular, in turbulent fluid flows, such unstable solutions are referred to as exact coherent structures (ECS) and play an important role in both initiating and sustaining turbulence. The nature of ECS and their role in organizing spatiotemporally chaotic dynamics, however, is reasonably well understood only for systems on relatively small spatial domains lacking continuous Euclidean symmetries. Construction of ECS on large domains and in the presence of continuous translational and/or rotational symmetries remains a challenge. This is especially true for models of excitable media which display spiral turbulence and for which the standard approach to computing ECS completely breaks down. This paper uses the Karma model of cardiac tissue to illustrate a potential approach that could allow computing a new class of ECS on large domains of arbitrary shape by decomposing them into a patchwork of solutions on smaller domains, or tiles, which retain Euclidean symmetries locally. PMID:25833430

  15. Exact coherent structures and chaotic dynamics in a model of cardiac tissue

    SciTech Connect

    Byrne, Greg; Marcotte, Christopher D.; Grigoriev, Roman O.

    2015-03-15

    Unstable nonchaotic solutions embedded in the chaotic attractor can provide significant new insight into chaotic dynamics of both low- and high-dimensional systems. In particular, in turbulent fluid flows, such unstable solutions are referred to as exact coherent structures (ECS) and play an important role in both initiating and sustaining turbulence. The nature of ECS and their role in organizing spatiotemporally chaotic dynamics, however, is reasonably well understood only for systems on relatively small spatial domains lacking continuous Euclidean symmetries. Construction of ECS on large domains and in the presence of continuous translational and/or rotational symmetries remains a challenge. This is especially true for models of excitable media which display spiral turbulence and for which the standard approach to computing ECS completely breaks down. This paper uses the Karma model of cardiac tissue to illustrate a potential approach that could allow computing a new class of ECS on large domains of arbitrary shape by decomposing them into a patchwork of solutions on smaller domains, or tiles, which retain Euclidean symmetries locally.

  16. Cardiac and vascular responses of isolated rat tissues treated with diterpenes from Sinularia flexibilis (coelenterata: octocorallia).

    PubMed

    Aceret, T L; Brown, L; Miller, J; Coll, J C; Sammarco, P W

    1996-10-01

    The marine environment is a rich source of compounds with cardiovascular activity. This study characterizes the cardiac and vascular responses in isolated rat tissues of flexibilide, dihydroflexibilide and sinulariolide, three diterpenes isolated from the soft coral Sinularia flexibilis. On rat left ventricular papillary muscles, dihydroflexibilide and flexibilide showed similar potencies (-log EC50 = 4.69 +/- 0.05 and 4.66 +/- 0.06, respectively); the maximal response to dihydroflexibilide of 1.4 +/- 0.2 mN was 35 +/- 7% that of calcium chloride in the same muscles. All diterpenes relaxed rat thoracic aortic rings precontracted with KC1 (100 mM) with similar potencies (flexibilide, -log EC50 = 4.17 +/- 0.06). Flexibilide was further characterized and shown to increase force in isolated rat left atria by 0.8 +/- 0.5 mN at 1 x 10(-4) M, to increase rate of contraction in isolated rat right atria by 18 +/- 5 beta/min at 3 x 10(-5) M and to completely relax endothelium-denuded rat thoracic aortic rings (-log EC50 = 4.14 +/- 0.05). Toxicity as indicated by the occurrence of ectopic beats was not observed with the diterpenes at concentrations which produced complete relaxation of blood vessels, maximal positive inotropic activity and minor positive chronotropic responses. Thus, these compounds may be useful lead compounds in the search for improved treatment of cardiovascular disease, especially heart failure. PMID:8931257

  17. Exercise training characteristics in cardiac rehabilitation programmes: a cross-sectional survey of Australian practice

    PubMed Central

    Abell, Bridget; Glasziou, Paul; Briffa, Tom; Hoffmann, Tammy

    2016-01-01

    Introduction Exercise training is a core component of cardiac rehabilitation (CR), however, little information exists regarding the specific exercise interventions currently provided for coronary heart disease in Australian practice. We aimed to analyse the current status of exercise-based CR services across Australia. Design Cross-sectional survey. Methods Australian sites offering exercise-based CR were identified from publically available directories. All sites were invited by email to participate in an online Survey Monkey questionnaire between October 2014 and March 2015, with reminders via email and phone follow-up. Questions investigated the demographics and format of individual programmes, as well as specific exercise training characteristics. Results 297 eligible programmes were identified, with an 82% response rate. Most sites (82%) were based at hospital or outpatient centres, with home (15%), community (18%) or gym-based options (5%) less common. While CR was most often offered in a comprehensive format (72% of sites), the level of exercise intervention varied greatly among programmes. Most frequently, exercise was prescribed 1–2 times per week for 60 min over 7 weeks. Almost one-quarter (24%) had a sole practitioner supervising exercise, although the majority used a nurse/physiotherapist combination. Low to moderate exercise intensities were used in 60% of programmes, however, higher intensity prescriptions were not uncommon. Few sites (<6%) made use of technology, such as mobile phones or the internet, to deliver or support exercise training. Conclusions While advances have been made towards providing flexible and accessible exercise-based CR, much of Australia's service remains within traditional models of care. A continuing focus on service improvement and evidence-based care should, therefore, be considered a core aim of those providing exercise for CR in order to improve health service delivery and optimise outcomes for patients. PMID

  18. Increased interstitial loading reduces the effect of microstructural variations in cardiac tissue

    PubMed Central

    Henriquez, Craig S.

    2010-01-01

    Electrical propagation in diseased and aging hearts is strongly influenced by structural changes that occur in both the intracellular and interstitial spaces of cardiac tissue; however, very few studies have investigated how interactions between the two spaces affect propagation at the microscale. In this study, we used one-dimensional microstructural computer models of interconnected ventricular myocytes to systematically investigate how increasing the effective interstitial resistivity (ρoeff) influences action potential propagation in fibers with variations in intracellular properties such as cell coupling and cell length. Changes in ρoeff were incorporated into a monodomain model using a correction to the intracellular properties that was based on bidomain simulations. The results showed that increasing ρoeff in poorly coupled one-dimensional fibers alters the distribution of electrical load at the microscale and causes propagation to become more continuous. In the poorly coupled fiber, this continuous state is characterized by decreased gap junction delay, sustained conduction velocity, increased sodium current, reduced maximum upstroke velocity, and increased safety factor. Long, poorly coupled cells experience greater loading effects than short cells and show the greatest initial response to changes in ρoeff. In inhomogeneous fibers with adjacent well-coupled and poorly coupled regions, increasing ρoeff in the poorly coupled region also reduces source-load mismatch, which delays the onset of conduction block and reduces the dispersion of repolarization at the transition between the two regions. Increasing the ρoeff minimizes the effect of cell-to-cell variations and may influence the pattern of activation in critical regimes characterized by low intercellular coupling, microstructural heterogeneity, and reduced or abnormal membrane excitability. PMID:20097772

  19. Human Engineered Cardiac Tissues Created Using Induced Pluripotent Stem Cells Reveal Functional Characteristics of BRAF-Mediated Hypertrophic Cardiomyopathy

    PubMed Central

    Johnson, Bryce V.; Gelb, Bruce D.; Costa, Kevin D.

    2016-01-01

    Hypertrophic cardiomyopathy (HCM) is a leading cause of sudden cardiac death that often goes undetected in the general population. HCM is also prevalent in patients with cardio-facio-cutaneous syndrome (CFCS), which is a genetic disorder characterized by aberrant signaling in the RAS/MAPK signaling cascade. Understanding the mechanisms of HCM development in such RASopathies may lead to novel therapeutic strategies, but relevant experimental models of the human condition are lacking. Therefore, the objective of this study was to develop the first 3D human engineered cardiac tissue (hECT) model of HCM. The hECTs were created using human cardiomyocytes obtained by directed differentiation of induced pluripotent stem cells derived from a patient with CFCS due to an activating BRAF mutation. The mutant myocytes were directly conjugated at a 3:1 ratio with a stromal cell population to create a tissue of defined composition. Compared to healthy patient control hECTs, BRAF-hECTs displayed a hypertrophic phenotype by culture day 6, with significantly increased tissue size, twitch force, and atrial natriuretic peptide (ANP) gene expression. Twitch characteristics reflected increased contraction and relaxation rates and shorter twitch duration in BRAF-hECTs, which also had a significantly higher maximum capture rate and lower excitation threshold during electrical pacing, consistent with a more arrhythmogenic substrate. By culture day 11, twitch force was no longer different between BRAF and wild-type hECTs, revealing a temporal aspect of disease modeling with tissue engineering. Principal component analysis identified diastolic force as a key factor that changed from day 6 to day 11, supported by a higher passive stiffness in day 11 BRAF-hECTs. In summary, human engineered cardiac tissues created from BRAF mutant cells recapitulated, for the first time, key aspects of the HCM phenotype, offering a new in vitro model for studying intrinsic mechanisms and screening new

  20. Human Engineered Cardiac Tissues Created Using Induced Pluripotent Stem Cells Reveal Functional Characteristics of BRAF-Mediated Hypertrophic Cardiomyopathy.

    PubMed

    Cashman, Timothy J; Josowitz, Rebecca; Johnson, Bryce V; Gelb, Bruce D; Costa, Kevin D

    2016-01-01

    Hypertrophic cardiomyopathy (HCM) is a leading cause of sudden cardiac death that often goes undetected in the general population. HCM is also prevalent in patients with cardio-facio-cutaneous syndrome (CFCS), which is a genetic disorder characterized by aberrant signaling in the RAS/MAPK signaling cascade. Understanding the mechanisms of HCM development in such RASopathies may lead to novel therapeutic strategies, but relevant experimental models of the human condition are lacking. Therefore, the objective of this study was to develop the first 3D human engineered cardiac tissue (hECT) model of HCM. The hECTs were created using human cardiomyocytes obtained by directed differentiation of induced pluripotent stem cells derived from a patient with CFCS due to an activating BRAF mutation. The mutant myocytes were directly conjugated at a 3:1 ratio with a stromal cell population to create a tissue of defined composition. Compared to healthy patient control hECTs, BRAF-hECTs displayed a hypertrophic phenotype by culture day 6, with significantly increased tissue size, twitch force, and atrial natriuretic peptide (ANP) gene expression. Twitch characteristics reflected increased contraction and relaxation rates and shorter twitch duration in BRAF-hECTs, which also had a significantly higher maximum capture rate and lower excitation threshold during electrical pacing, consistent with a more arrhythmogenic substrate. By culture day 11, twitch force was no longer different between BRAF and wild-type hECTs, revealing a temporal aspect of disease modeling with tissue engineering. Principal component analysis identified diastolic force as a key factor that changed from day 6 to day 11, supported by a higher passive stiffness in day 11 BRAF-hECTs. In summary, human engineered cardiac tissues created from BRAF mutant cells recapitulated, for the first time, key aspects of the HCM phenotype, offering a new in vitro model for studying intrinsic mechanisms and screening new

  1. ACE2 Deficiency Worsens Epicardial Adipose Tissue Inflammation and Cardiac Dysfunction in Response to Diet-Induced Obesity.

    PubMed

    Patel, Vaibhav B; Mori, Jun; McLean, Brent A; Basu, Ratnadeep; Das, Subhash K; Ramprasath, Tharmarajan; Parajuli, Nirmal; Penninger, Josef M; Grant, Maria B; Lopaschuk, Gary D; Oudit, Gavin Y

    2016-01-01

    Obesity is increasing in prevalence and is strongly associated with metabolic and cardiovascular disorders. The renin-angiotensin system (RAS) has emerged as a key pathogenic mechanism for these disorders; angiotensin (Ang)-converting enzyme 2 (ACE2) negatively regulates RAS by metabolizing Ang II into Ang 1-7. We studied the role of ACE2 in obesity-mediated cardiac dysfunction. ACE2 null (ACE2KO) and wild-type (WT) mice were fed a high-fat diet (HFD) or a control diet and studied at 6 months of age. Loss of ACE2 resulted in decreased weight gain but increased glucose intolerance, epicardial adipose tissue (EAT) inflammation, and polarization of macrophages into a proinflammatory phenotype in response to HFD. Similarly, human EAT in patients with obesity and heart failure displayed a proinflammatory macrophage phenotype. Exacerbated EAT inflammation in ACE2KO-HFD mice was associated with decreased myocardial adiponectin, decreased phosphorylation of AMPK, increased cardiac steatosis and lipotoxicity, and myocardial insulin resistance, which worsened heart function. Ang 1-7 (24 µg/kg/h) administered to ACE2KO-HFD mice resulted in ameliorated EAT inflammation and reduced cardiac steatosis and lipotoxicity, resulting in normalization of heart failure. In conclusion, ACE2 plays a novel role in heart disease associated with obesity wherein ACE2 negatively regulates obesity-induced EAT inflammation and cardiac insulin resistance. PMID:26224885

  2. Raman spectroscopic analysis of human skin tissue sections ex-vivo: evaluation of the effects of tissue processing and dewaxing

    NASA Astrophysics Data System (ADS)

    Ali, Syed M.; Bonnier, Franck; Tfayli, Ali; Lambkin, Helen; Flynn, Kathleen; McDonagh, Vincent; Healy, Claragh; Clive Lee, T.; Lyng, Fiona M.; Byrne, Hugh J.

    2013-06-01

    Raman spectroscopy coupled with K-means clustering analysis (KMCA) is employed to elucidate the biochemical structure of human skin tissue sections and the effects of tissue processing. Both hand and thigh sections of human cadavers were analyzed in their unprocessed and formalin-fixed, paraffin-processed (FFPP), and subsequently dewaxed forms. In unprocessed sections, KMCA reveals clear differentiation of the stratum corneum (SC), intermediate underlying epithelium, and dermal layers for sections from both anatomical sites. The SC is seen to be relatively rich in lipidic content; the spectrum of the subjacent layers is strongly influenced by the presence of melanin, while that of the dermis is dominated by the characteristics of collagen. For a given anatomical site, little difference in layer structure and biochemistry is observed between samples from different cadavers. However, the hand and thigh sections are consistently differentiated for all cadavers, largely based on lipidic profiles. In dewaxed FFPP samples, while the SC, intermediate, and dermal layers are clearly differentiated by KMCA of Raman maps of tissue sections, the lipidic contributions to the spectra are significantly reduced, with the result that respective skin layers from different anatomical sites become indistinguishable. While efficient at removing the fixing wax, the tissue processing also efficiently removes the structurally similar lipidic components of the skin layers. In studies of dermatological processes in which lipids play an important role, such as wound healing, dewaxed samples are therefore not appropriate. Removal of the lipids does however accentuate the spectral features of the cellular and protein components, which may be more appropriate for retrospective analysis of disease progression and biochemical analysis using tissue banks.

  3. Correlation-based discrimination between cardiac tissue and blood for segmentation of the left ventricle in 3-D echocardiographic images.

    PubMed

    Saris, Anne E C M; Nillesen, Maartje M; Lopata, Richard G P; de Korte, Chris L

    2014-03-01

    For automated segmentation of 3-D echocardiographic images, incorporation of temporal information may be helpful. In this study, optimal settings for calculation of temporal cross-correlations between subsequent time frames were determined, to obtain the maximum cross-correlation (MCC) values that provided the best contrast between blood and cardiac tissue over the entire cardiac cycle. Both contrast and boundary gradient quality measures were assessed to optimize MCC values with respect to signal choice (radiofrequency or envelope data) and axial window size. Optimal MCC values were incorporated into a deformable model to automatically segment the left ventricular cavity. MCC values were tested against, and combined with, filtered, demodulated radiofrequency data. Results reveal that using envelope data in combination with a relatively small axial window (0.7-1.25 mm) at fine scale results in optimal contrast and boundary gradient between the two tissues over the entire cardiac cycle. Preliminary segmentation results indicate that incorporation of MCC values has additional value for automated segmentation of the left ventricle. PMID:24412178

  4. ACE2/Ang 1-7 axis: A critical regulator of epicardial adipose tissue inflammation and cardiac dysfunction in obesity.

    PubMed

    Patel, Vaibhav B; Basu, Ratnadeep; Oudit, Gavin Y

    2016-01-01

    Obesity is characterized by an excessive fat accumulation in adipose tissues leading to weight gain and is increasing in prevalence and is strongly associated with metabolic and cardiovascular disorders. The renin-angiotensin system (RAS) has emerged as a key pathogenic mechanism for these disorders; activated RAS and angiotensin (Ang) II production results in worsening of cardiovascular diseases and angiotensin converting enzyme 2 (ACE2) negatively regulates RAS by metabolizing Ang II into Ang 1-7. ACE2 is expressed in the adipocytes and its expression is upregulated in response to high fat diet induced obesity in mice. Loss of ACE2 results in heart failure with preserved ejection fraction which is mediated in part by epicardial adipose tissue inflammation. Angiotensin 1-7 reduces the obesity associated cardiac dysfunction predominantly via its role in adiponectin expression and attenuation of epicardial adipose tissue inflammation. Human heart disease is also linked with inflammed epicardial adipose tissue. Here, we discuss the important interpretation of the novel of ACE2/Ang 1-7 pathway in obesity associated cardiac dysfunction. PMID:27617176

  5. Rapid OTAN method for localizing unsaturated lipids in lung tissue sections.

    PubMed

    Negi, D S; Stephens, R J

    1981-05-01

    The OTAN treatment, which is the only histochemical method available at present for the simultaneous localization of hydrophobic and hydrophilic unsaturated lipids in tissue sections, requires unduly long exposure to OsO4 and use of free-floating sections, which makes handling the sections difficult and often results in their loss or damage. Simple modifications using OsO4 treatment at 37 C and slide-mounted sections eliminate the practical drawbacks of the existing method and provide as good or better localization in less than one-eight of the time. The modified method is applicable to fixed as well as fresh frozen tissues. PMID:7268814

  6. Hypoxia-induced epigenetic modifications are associated with cardiac tissue fibrosis and the development of a myofibroblast-like phenotype.

    PubMed

    Watson, Chris J; Collier, Patrick; Tea, Isaac; Neary, Roisin; Watson, Jenny A; Robinson, Claire; Phelan, Dermot; Ledwidge, Mark T; McDonald, Kenneth M; McCann, Amanda; Sharaf, Osama; Baugh, John A

    2014-04-15

    Ischemia caused by coronary artery disease and myocardial infarction leads to aberrant ventricular remodeling and cardiac fibrosis. This occurs partly through accumulation of gene expression changes in resident fibroblasts, resulting in an overactive fibrotic phenotype. Long-term adaptation to a hypoxic insult is likely to require significant modification of chromatin structure in order to maintain the fibrotic phenotype. Epigenetic changes may play an important role in modulating hypoxia-induced fibrosis within the heart. Therefore, the aim of the study was to investigate the potential pro-fibrotic impact of hypoxia on cardiac fibroblasts and determine whether alterations in DNA methylation could play a role in this process. This study found that within human cardiac tissue, the degree of hypoxia was associated with increased expression of collagen 1 and alpha-smooth muscle actin (ASMA). In addition, human cardiac fibroblast cells exposed to prolonged 1% hypoxia resulted in a pro-fibrotic state. These hypoxia-induced pro-fibrotic changes were associated with global DNA hypermethylation and increased expression of the DNA methyltransferase (DNMT) enzymes DNMT1 and DNMT3B. Expression of these methylating enzymes was shown to be regulated by hypoxia-inducible factor (HIF)-1α. Using siRNA to block DNMT3B expression significantly reduced collagen 1 and ASMA expression. In addition, application of the DNMT inhibitor 5-aza-2'-deoxycytidine suppressed the pro-fibrotic effects of TGFβ. Epigenetic modifications and changes in the epigenetic machinery identified in cardiac fibroblasts during prolonged hypoxia may contribute to the pro-fibrotic nature of the ischemic milieu. Targeting up-regulated expression of DNMTs in ischemic heart disease may prove to be a valuable therapeutic approach. PMID:24301681

  7. Angiotensin II (AT(1)) receptor blockade reduces vascular tissue factor in angiotensin II-induced cardiac vasculopathy.

    PubMed

    Müller, D N; Mervaala, E M; Dechend, R; Fiebeler, A; Park, J K; Schmidt, F; Theuer, J; Breu, V; Mackman, N; Luther, T; Schneider, W; Gulba, D; Ganten, D; Haller, H; Luft, F C

    2000-07-01

    Tissue factor (TF), a main initiator of clotting, is up-regulated in vasculopathy. We tested the hypothesis that chronic in vivo angiotensin (ANG) II receptor AT(1) receptor blockade inhibits TF expression in a model of ANG II-induced cardiac vasculopathy. Furthermore, we explored the mechanisms by examining transcription factor activation and analyzing the TF promoter. Untreated transgenic rats overexpressing the human renin and angiotensinogen genes (dTGR) feature hypertension and severe left ventricular hypertrophy with focal areas of necrosis, and die at age 7 weeks. Plasma and cardiac ANG II was three- to fivefold increased compared to Sprague-Dawley rats. Chronic treatment with valsartan normalized blood pressure and coronary resistance completely, and ameliorated cardiac hypertrophy (P < 0.001). Valsartan prevented monocyte/macrophage infiltration, nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) activation, and c-fos expression in dTGR hearts. NF-kappaB subunit p65 and TF expression was increased in the endothelium and media of cardiac vessels and markedly reduced by valsartan treatment. To analyze the mechanism of TF transcription, we then transfected human coronary artery smooth muscle cells and Chinese hamster ovary cells overexpressing the AT(1) receptor with plasmids containing the human TF promoter and the luciferase reporter gene. ANG II induced the full-length TF promoter in both transfected cell lines. TF transcription was abolished by AT(1) receptor blockade. Deletion of both AP-1 and NF-kappaB sites reduced ANG II-induced TF gene transcription completely, whereas the deletion of AP-1 sites reduced transcription. Thus, the present study clearly shows an aberrant TF expression in the endothelium and media in rats with ANG II-induced vasculopathy. The beneficial effects of AT(1) receptor blockade in this model are mediated via the inhibition of NF-kappaB and AP-1 activation, thereby preventing TF expression, cardiac vasculopathy, and

  8. Angiotensin II (AT1) Receptor Blockade Reduces Vascular Tissue Factor in Angiotensin II-Induced Cardiac Vasculopathy

    PubMed Central

    Müller, Dominik N.; Mervaala, Eero M. A.; Dechend, Ralf; Fiebeler, Anette; Park, Joon-Keun; Schmidt, Folke; Theuer, Jürgen; Breu, Volker; Mackman, Nigel; Luther, Thomas; Schneider, Wolfgang; Gulba, Dietrich; Ganten, Detlev; Haller, Hermann; Luft, Friedrich C.

    2000-01-01

    Tissue factor (TF), a main initiator of clotting, is up-regulated in vasculopathy. We tested the hypothesis that chronic in vivo angiotensin (ANG) II receptor AT1 receptor blockade inhibits TF expression in a model of ANG II-induced cardiac vasculopathy. Furthermore, we explored the mechanisms by examining transcription factor activation and analyzing the TF promoter. Untreated transgenic rats overexpressing the human renin and angiotensinogen genes (dTGR) feature hypertension and severe left ventricular hypertrophy with focal areas of necrosis, and die at age 7 weeks. Plasma and cardiac ANG II was three- to fivefold increased compared to Sprague-Dawley rats. Chronic treatment with valsartan normalized blood pressure and coronary resistance completely, and ameliorated cardiac hypertrophy (P < 0.001). Valsartan prevented monocyte/macrophage infiltration, nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) activation, and c-fos expression in dTGR hearts. NF-κB subunit p65 and TF expression was increased in the endothelium and media of cardiac vessels and markedly reduced by valsartan treatment. To analyze the mechanism of TF transcription, we then transfected human coronary artery smooth muscle cells and Chinese hamster ovary cells overexpressing the AT1 receptor with plasmids containing the human TF promoter and the luciferase reporter gene. ANG II induced the full-length TF promoter in both transfected cell lines. TF transcription was abolished by AT1 receptor blockade. Deletion of both AP-1 and NF-κB sites reduced ANG II-induced TF gene transcription completely, whereas the deletion of AP-1 sites reduced transcription. Thus, the present study clearly shows an aberrant TF expression in the endothelium and media in rats with ANG II-induced vasculopathy. The beneficial effects of AT1 receptor blockade in this model are mediated via the inhibition of NF-κB and AP-1 activation, thereby preventing TF expression, cardiac vasculopathy, and microinfarctions. PMID

  9. “The state of the heart”: Recent advances in engineering human cardiac tissue from pluripotent stem cells

    PubMed Central

    Sirabella, Dario; Cimetta, Elisa; Vunjak-Novakovic, Gordana

    2016-01-01

    The pressing need for effective cell therapy for the heart has led to the investigation of suitable cell sources for tissue replacement. In recent years, human pluripotent stem cell research expanded tremendously, in particular since the derivation of human induced pluripotent stem cells. In parallel, bioengineering technologies have led to novel approaches for in vitro cell culture. The combination of these two fields holds potential for in vitro generation of high-fidelity heart tissue, both for basic research and for therapeutic applications. However, this new multidisciplinary science is still at an early stage. Many questions need to be answered and improvements need to be made before clinical applications become a reality. Here we discuss the current status of human stem cell differentiation into cardiomyocytes and the combined use of bioengineering approaches for cardiac tissue formation and maturation in developmental studies, disease modeling, drug testing and regenerative medicine. PMID:26069271

  10. A multistep procedure to prepare pre-vascularized cardiac tissue constructs using adult stem sells, dynamic cell cultures, and porous scaffolds

    PubMed Central

    Pagliari, Stefania; Tirella, Annalisa; Ahluwalia, Arti; Duim, Sjoerd; Goumans, Marie-Josè; Aoyagi, Takao; Forte, Giancarlo

    2014-01-01

    The vascularization of tissue engineered products represents a key issue in regenerative medicine which needs to be addressed before the translation of these protocols to the bedside can be foreseen. Here we propose a multistep procedure to prepare pre-vascularized three-dimensional (3D) cardiac bio-substitutes using dynamic cell cultures and highly porous biocompatible gelatin scaffolds. The strategy adopted exploits the peculiar differentiation potential of two distinct subsets of adult stem cells to obtain human vascularized 3D cardiac tissues. In the first step of the procedure, human mesenchymal stem cells (hMSCs) are seeded onto gelatin scaffolds to provide interconnected vessel-like structures, while human cardiomyocyte progenitor cells (hCMPCs) are stimulated in vitro to obtain their commitment toward the cardiac phenotype. The use of a modular bioreactor allows the perfusion of the whole scaffold, providing superior performance in terms of cardiac tissue maturation and cell survival. Both the cell culture on natural-derived polymers and the continuous medium perfusion of the scaffold led to the formation of a densely packaged proto-tissue composed of vascular-like and cardiac-like cells, which might complete maturation process and interconnect with native tissue upon in vivo implantation. In conclusion, the data obtained through the approach here proposed highlight the importance to provide stem cells with complementary signals in vitro able to resemble the complexity of cardiac microenvironment. PMID:24917827

  11. Tissue-specific expression of the human brain natriuretic peptide gene in cardiac myocytes.

    PubMed

    LaPointe, M C; Wu, G; Garami, M; Yang, X P; Gardner, D G

    1996-03-01

    Brain natriuretic peptide (BNP) is a cardiac hormone constitutively expressed in the adult heart. To identify the cis-acting elements involved in regulation of the human BNP gene, we subcloned the full-length promoter (-1818 to +100) and deletions thereof upstream from a luciferase reporter gene and transiently transfected them into primary cultures of neonatal rat atrial and ventricular myocytes and myocardial fibroblasts. Luciferase activity of the full-length construct was higher in ventricular (39064 +/- 8488 relative light units, N=11) and atrial (11225 +/- 1907, N=17) myocytes than myocardial fibroblasts (329 +/- 113, n=5). Maximal promoter activity in ventricular and atrial myocytes was maintained by sequences positioned between -1818 and -1283 relative to the transcription start site. Deletion to -1175 resulted in a decrease, whereas further deletion to -500 effected an increase in reporter activity in both cell types. In ventricular and atrial myocytes, deletion from -500 to -40 reduced luciferase activity 20-fold and 2-fold, respectively, whereas in myocardial fibroblasts, deletion to -40 upregulated the BNP promoter 2-fold. Of note, deleting 16 bp between -127 and -111 reduced luciferase activity 7-fold and 4-fold in ventricular and atrial myocytes, respectively, but had essentially no effect on luciferase activity in fibroblasts. Placement of sequences lying between -127 and -40 upstream from a heterologous thymidine kinase promoter resulted in reporter expression that was 7.4-fold greater than the vector alone in ventricular myocytes, approximately 2-fold greater in atrial myocytes, and equivalent to the vector alone in fibroblasts. For study of activity of the human BNP promoter in adult myocytes, either 408 or 97 bp of 5' flanking sequence coupled to the luciferase reporter gene was injected into the apex of adult male Sprague-Dawley rat hearts. After 7 days, luciferase activity in the injected myocardium was 9.8-fold higher for the longer construct

  12. A Novel Miniaturized Multimodal Bioreactor for Continuous In Situ Assessment of Bioartificial Cardiac Tissue During Stimulation and Maturation

    PubMed Central

    Kensah, George; Viering, Jörg; Schumann, Henning; Dahlmann, Julia; Meyer, Heiko; Skvorc, David; Bär, Antonia; Akhyari, Payam; Heisterkamp, Alexander; Haverich, Axel; Martin, Ulrich

    2011-01-01

    Stem cell-based cardiac tissue engineering is a promising approach for regenerative therapy of the injured heart. At present, the small number of stem cell-derived cardiomyocytes that can be obtained using current culture and enrichment techniques represents one of the key limitations for the development of functional bioartificial cardiac tissue (BCT). We have addressed this problem by construction of a novel bioreactor with functional features of larger systems that enables the generation and in situ monitoring of miniaturized BCTs. BCTs were generated from rat cardiomyocytes to demonstrate advantages and usefulness of the bioreactor. Tissues showed spontaneous, synchronized contractions with cell orientation along the axis of strain. Cyclic stretch induced cardiomyocyte hypertrophy, demonstrated by a shift of myosin heavy chain expression from the alpha to beta isoform, together with elevated levels of atrial natriuretic factor. Stretch led to a moderate increase in systolic force (1.42 ± 0.09 mN vs. 0.96 ± 0.09 mN in controls), with significantly higher forces observed after β-adrenergic stimulation with noradrenalin (2.54 ± 0.11 mN). Combined mechanical and β-adrenergic stimulation had no synergistic effect. This study demonstrates for the first time that mechanical stimulation and direct real-time contraction force measurement can be combined into a single multimodal bioreactor system, including electrical stimulation of excitable tissue, perfusion of the culture chamber, and the possibility of (fluorescence) microscopic assessment during continuous cultivation. Thus, this bioreactor represents a valuable tool for monitoring tissue development and, ultimately, the optimization of stem cell-based tissue replacement strategies in regenerative medicine. PMID:21142417

  13. Mathematical Models Based on Transfer Functions to Estimate Tissue Temperature During RF Cardiac Ablation in Real Time

    PubMed Central

    Alba-Martínez, Jose; Trujillo, Macarena; Blasco-Gimenez, Ramon; Berjano, Enrique

    2012-01-01

    Radiofrequency cardiac ablation (RFCA) has been used to treat certain types of cardiac arrhythmias by producing a thermal lesion. Even though a tissue temperature higher than 50ºC is required to destroy the target, thermal mapping is not currently used during RFCA. Our aim was thus to develop mathematical models capable of estimating tissue temperature from tissue characteristics acquired or estimated at the beginning of the procedure (electrical conductivity, thermal conductivity, specific heat and density) and the applied voltage at any time. Biological tissue was considered as a system with an input (applied voltage) and output (tissue temperature), and so the mathematical models were based on transfer functions relating these variables. We used theoretical models based on finite element method to verify the mathematical models. Firstly, we solved finite element models to identify the transfer functions between the temperature at a depth of 4 mm and a constant applied voltage using a 7Fr and 4 mm electrode. The results showed that the relationships can be expressed as first-order transfer functions. Changes in electrical conductivity only affected the static gain of the system, while specific heat variations produced a change in the dynamic system response. In contrast, variations in thermal conductivity modified both the static gain and the dynamic system response. Finally, to assess the performance of the transfer functions obtained, we conducted a new set of computer simulations using a controlled temperature protocol and considering the temperature dependence of the thermal and electrical conductivities, i.e. conditions closer to those found in clinical use. The results showed that the difference between the values estimated from transfer functions and the temperatures obtained from finite element models was less than 4ºC, which suggests that the proposed method could be used to estimate tissue temperature in real time. PMID:22715345

  14. Factors influencing the degradation of archival formalin-fixed paraffin-embedded tissue sections.

    PubMed

    Xie, Ran; Chung, Joon-Yong; Ylaya, Kris; Williams, Reginald L; Guerrero, Natalie; Nakatsuka, Nathan; Badie, Cortessia; Hewitt, Stephen M

    2011-04-01

    The loss of antigenicity in archival formalin-fixed paraffin-embedded (FFPE) tissue sections negatively affects both diagnostic histopathology and advanced molecular studies. The mechanisms underlying antigenicity loss in FFPE tissues remain unclear. The authors hypothesize that water is a crucial contributor to protein degradation and decrement of immunoreactivity in FFPE tissues. To test their hypothesis, they examined fixation time, processing time, and humidity of storage environment on protein integrity and antigenicity by immunohistochemistry, Western blotting, and protein extraction. This study revealed that inadequate tissue processing, resulting in retention of endogenous water in tissue sections, results in antigen degradation. Exposure to high humidity during storage results in significant protein degradation and reduced immunoreactivity, and the effects of storage humidity are temperature dependent. Slides stored under vacuum with desiccant do not protect against the effects of residual water from inadequate tissue processing. These results support that the presence of water, both endogenously and exogenously, plays a central role in antigenicity loss. Optimal tissue processing is essential. The parameters of optimal storage of unstained slides remain to be defined, as they are directly affected by preanalytic variables. Nevertheless, minimization of exposure to water is required for antigen preservation in FFPE tissue sections. PMID:21411807

  15. Confocal Microscopy of thick tissue sections: 3D Visualization of rat kidney glomeruli

    EPA Science Inventory

    Confocal laser scanning microscopy (CLSM) as a technique capable of generating serial sections of whole-mount tissue and then reassembling the computer-acquired images as a virtual 3-dimentional structure. In many ways CLSM offers an alternative to traditional sectioning approac...

  16. Confocal microscopy of thick tissue sections: 3D visualizaiton of rat kidney glomeruli

    EPA Science Inventory

    Confocal laser scanning microscopy (CLSM) as a technique capable of generating serial sections of whole-mount tissue and then reassembling the computer-acquired images as a virtual 3-dimentional structure. In many ways CLSM offers an alternative to traditional sectioning approac...

  17. Zearalenone-induced changes in biochemical parameters, oxidative stress and apoptosis in cardiac tissue: Protective role of crocin.

    PubMed

    Salem, I Ben; Boussabbeh, M; Neffati, F; Najjar, M F; Abid-Essefi, S; Bacha, H

    2016-06-01

    Zearalenone (ZEN) is a mycotoxin from Fusarium species commonly found in food commodities and is known to cause reproductive disorders. Several in vivo studies have shown that ZEN is haematotoxic and hepatotoxic and causes several alterations of immunological parameters. Meantime, the available information on the cardiotoxic effects of ZEN is very much limited. In the present study, we investigated the toxic effects of ZEN in heart tissues of Balb/c mice. We demonstrated that ZEN (40 mg kg(-1) body weight (b.w.)) increased creatine phosphokinase, lactate dehydrogenase, aspartate transaminase, alanine transaminase, total cholesterol and triglyceride levels and induced oxidative stress as monitored by measuring the malondialdehyde level, the generation of protein carbonyls, the catalase and superoxide dismutase activity and the expression of the heat shock proteins (Hsp 70). We also demonstrated that acute administration of ZEN triggers apoptosis in cardiac tissue. Furthermore, we aimed to evaluate the safety and efficacy of crocin (CRO), a natural carotenoid, to prevent ZEN-induced cardiotoxicity in mice. In fact, combined treatment of ZEN with different doses of CRO (50, 100, and 250 mg kg(-1) b.w.) showed a significant reduction of ZEN-induced toxicity for all tested markers in a dose-dependent manner. It could be concluded that CRO was effective in the protection against ZEN-induced toxicity in cardiac tissue. PMID:26231423

  18. Extraction of DNA from small sections of frozen tissue with simultaneous histological examination.

    PubMed Central

    Cotter, F E; Hall, P A; Young, B D

    1988-01-01

    Though analysis of small sections of biopsy material by molecular techniques permits increased sensitivity, it also requires accurate histological examination of the tissue in order to reduce sampling error. A technique for the extraction of DNA from small sections of frozen biopsy material with simultaneous histological examination from adjacent sections is described that may enhance the accuracy of characterisation of the tissue, particularly where there is focal variation. The quality of the DNA obtained enables a full range of molecular studies to be carried out. Images Fig 1 Fig 2 PMID:3192737

  19. Visualization and analysis of gene expression in tissue sections by spatial transcriptomics.

    PubMed

    Ståhl, Patrik L; Salmén, Fredrik; Vickovic, Sanja; Lundmark, Anna; Navarro, José Fernández; Magnusson, Jens; Giacomello, Stefania; Asp, Michaela; Westholm, Jakub O; Huss, Mikael; Mollbrink, Annelie; Linnarsson, Sten; Codeluppi, Simone; Borg, Åke; Pontén, Fredrik; Costea, Paul Igor; Sahlén, Pelin; Mulder, Jan; Bergmann, Olaf; Lundeberg, Joakim; Frisén, Jonas

    2016-07-01

    Analysis of the pattern of proteins or messengerRNAs (mRNAs) in histological tissue sections is a cornerstone in biomedical research and diagnostics. This typically involves the visualization of a few proteins or expressed genes at a time. We have devised a strategy, which we call "spatial transcriptomics," that allows visualization and quantitative analysis of the transcriptome with spatial resolution in individual tissue sections. By positioning histological sections on arrayed reverse transcription primers with unique positional barcodes, we demonstrate high-quality RNA-sequencing data with maintained two-dimensional positional information from the mouse brain and human breast cancer. Spatial transcriptomics provides quantitative gene expression data and visualization of the distribution of mRNAs within tissue sections and enables novel types of bioinformatics analyses, valuable in research and diagnostics. PMID:27365449

  20. Advanced computer techniques for inverse modeling of electric current in cardiac tissue

    SciTech Connect

    Hutchinson, S.A.; Romero, L.A.; Diegert, C.F.

    1996-08-01

    For many years, ECG`s and vector cardiograms have been the tools of choice for non-invasive diagnosis of cardiac conduction problems, such as found in reentrant tachycardia or Wolff-Parkinson-White (WPW) syndrome. Through skillful analysis of these skin-surface measurements of cardiac generated electric currents, a physician can deduce the general location of heart conduction irregularities. Using a combination of high-fidelity geometry modeling, advanced mathematical algorithms and massively parallel computing, Sandia`s approach would provide much more accurate information and thus allow the physician to pinpoint the source of an arrhythmia or abnormal conduction pathway.

  1. An inverse finite element method for determining the tissue compressibility of human left ventricular wall during the cardiac cycle.

    PubMed

    Hassaballah, Abdallah I; Hassan, Mohsen A; Mardi, Azizi N; Hamdi, Mohd

    2013-01-01

    The determination of the myocardium's tissue properties is important in constructing functional finite element (FE) models of the human heart. To obtain accurate properties especially for functional modeling of a heart, tissue properties have to be determined in vivo. At present, there are only few in vivo methods that can be applied to characterize the internal myocardium tissue mechanics. This work introduced and evaluated an FE inverse method to determine the myocardial tissue compressibility. Specifically, it combined an inverse FE method with the experimentally-measured left ventricular (LV) internal cavity pressure and volume versus time curves. Results indicated that the FE inverse method showed good correlation between LV repolarization and the variations in the myocardium tissue bulk modulus K (K = 1/compressibility), as well as provided an ability to describe in vivo human myocardium material behavior. The myocardium bulk modulus can be effectively used as a diagnostic tool of the heart ejection fraction. The model developed is proved to be robust and efficient. It offers a new perspective and means to the study of living-myocardium tissue properties, as it shows the variation of the bulk modulus throughout the cardiac cycle. PMID:24367544

  2. An Inverse Finite Element Method for Determining the Tissue Compressibility of Human Left Ventricular Wall during the Cardiac Cycle

    PubMed Central

    Hassaballah, Abdallah I.; Hassan, Mohsen A.; Mardi, Azizi N.; Hamdi, Mohd

    2013-01-01

    The determination of the myocardium’s tissue properties is important in constructing functional finite element (FE) models of the human heart. To obtain accurate properties especially for functional modeling of a heart, tissue properties have to be determined in vivo. At present, there are only few in vivo methods that can be applied to characterize the internal myocardium tissue mechanics. This work introduced and evaluated an FE inverse method to determine the myocardial tissue compressibility. Specifically, it combined an inverse FE method with the experimentally-measured left ventricular (LV) internal cavity pressure and volume versus time curves. Results indicated that the FE inverse method showed good correlation between LV repolarization and the variations in the myocardium tissue bulk modulus K (K = 1/compressibility), as well as provided an ability to describe in vivo human myocardium material behavior. The myocardium bulk modulus can be effectively used as a diagnostic tool of the heart ejection fraction. The model developed is proved to be robust and efficient. It offers a new perspective and means to the study of living-myocardium tissue properties, as it shows the variation of the bulk modulus throughout the cardiac cycle. PMID:24367544

  3. Spatially-resolved protein surface microsampling from tissue sections using liquid extraction surface analysis.

    PubMed

    Wisztorski, Maxence; Desmons, Annie; Quanico, Jusal; Fatou, Benoit; Gimeno, Jean-Pascal; Franck, Julien; Salzet, Michel; Fournier, Isabelle

    2016-06-01

    Tissue microenvironment characterization presents a challenge for a better understanding of the full complexity of a pathology. Unfortunately, making a precise "picture" of the disease needs an efficient microsampling method coupled to an accurate localization for performing region-dependent proteomics. Here, we present a method that enables rapid and reproducible extraction of proteins from a tissue section to analyze a specific region at a millimeter scale. The method used a liquid-microjunction extraction with conventional detergent solution for proteomics analysis. We successfully performed immunoblotting experiments and showed the possibility to retrieve and identify more than 1400 proteins from a 1-mm diameter spot size on tissue sections with a high degree of reproducibility both qualitatively and quantitatively. Moreover, the small size of the extracted region achieved by this sampling method allows the possibility to perform multiple extractions on different tissue section points. Ten points on a sagittal rat brain tissue section were analyzed and the measured proteins clearly distinguished the different parts of the brain, thus permitting precise functional mapping. We thus demonstrate that with this technology, it is possible to map the tissue microenvironment and gain an understanding of the molecular mechanisms at millimeter resolution. PMID:26929135

  4. Transplantation of adipose tissue-derived stem cells improves cardiac contractile function and electrical stability in a rat myocardial infarction model.

    PubMed

    Gautam, Milan; Fujita, Daiki; Kimura, Kazuhiro; Ichikawa, Hinako; Izawa, Atsushi; Hirose, Masamichi; Kashihara, Toshihide; Yamada, Mitsuhiko; Takahashi, Masafumi; Ikeda, Uichi; Shiba, Yuji

    2015-04-01

    The transplantation of adipose tissue-derived stem cells (ADSCs) improves cardiac contractility after myocardial infarction (MI); however, little is known about the electrophysiological consequences of transplantation. The purpose of this study was to clarify whether the transplantation of ADSCs increases or decreases the incidence of ventricular tachyarrhythmias (VT) in a rat model of MI. MI was induced experimentally by permanent occlusion of the left anterior descending artery of Lewis rats. ADSCs were harvested from GFP-transgenic rats, and were cultured until passage four. ADSCs (10×10(6)) resuspended in 100μL saline or pro-survival cocktail (PSC), which enhances cardiac graft survival, were injected directly into syngeneic rat hearts 1week after MI. The recipients of ADSCs suspended in PSC had a larger graft area compared with those receiving ASDCs suspended in saline at 1week post-transplantation (number of graft cells/section: 148.7±10.6 vs. 22.4±3.4, p<0.05, n=5/group). Thereafter, all ADSC recipients were transplanted with ASDCs in PSC. ADSCs were transplanted into infarcted hearts, and the mechanical and electrophysiological functions were assessed. Echocardiography revealed that ADSC recipients had improved contractile function compared with those receiving PSC vehicle (fractional shortening: 21.1±0.9 vs. 14.1±1.2, p<0.05, n≥12/group). Four weeks post-transplantation, VT was induced via in vivo programmed electrical stimulation. The recipients of ADSCs showed a significantly lower incidence of induced VT compared with the control (31.3% vs. 83.3%, p<0.05, n≥12/group). To understand the electrical activity following transplantation, we performed ex vivo optical mapping using a voltage sensitive dye, and found that ADSC transplantation decreased conduction velocity and its dispersion in the peri-infarct area. These results suggest that ADSC transplantation improved cardiac mechanical and electrophysiological functions in subacute MI. PMID

  5. Cardiomyocyte Circadian Oscillations Are Cell-Autonomous, Amplified by β-Adrenergic Signaling, and Synchronized in Cardiac Ventricle Tissue

    PubMed Central

    Welsh, David K.

    2016-01-01

    Circadian clocks impact vital cardiac parameters such as blood pressure and heart rate, and adverse cardiac events such as myocardial infarction and sudden cardiac death. In mammals, the central circadian pacemaker, located in the suprachiasmatic nucleus of the hypothalamus, synchronizes cellular circadian clocks in the heart and many other tissues throughout the body. Cardiac ventricle explants maintain autonomous contractions and robust circadian oscillations of clock gene expression in culture. In the present study, we examined the relationship between intrinsic myocardial function and circadian rhythms in cultures from mouse heart. We cultured ventricular explants or dispersed cardiomyocytes from neonatal mice expressing a PER2::LUC bioluminescent reporter of circadian clock gene expression. We found that isoproterenol, a β-adrenoceptor agonist known to increase heart rate and contractility, also amplifies PER2 circadian rhythms in ventricular explants. We found robust, cell-autonomous PER2 circadian rhythms in dispersed cardiomyocytes. Single-cell rhythms were initially synchronized in ventricular explants but desynchronized in dispersed cells. In addition, we developed a method for long-term, simultaneous monitoring of clock gene expression, contraction rate, and basal intracellular Ca2+ level in cardiomyocytes using PER2::LUC in combination with GCaMP3, a genetically encoded fluorescent Ca2+ reporter. In contrast to robust PER2 circadian rhythms in cardiomyocytes, we detected no rhythms in contraction rate and only weak rhythms in basal Ca2+ level. In summary, we found that PER2 circadian rhythms of cardiomyocytes are cell-autonomous, amplified by adrenergic signaling, and synchronized by intercellular communication in ventricle explants, but we detected no robust circadian rhythms in contraction rate or basal Ca2+. PMID:27459195

  6. A procedure for tissue freezing and processing applicable to both intra-operative frozen section diagnosis and tissue banking in surgical pathology.

    PubMed

    Steu, Susanne; Baucamp, Maya; von Dach, Gabriela; Bawohl, Marion; Dettwiler, Susanne; Storz, Martina; Moch, Holger; Schraml, Peter

    2008-03-01

    Different methods for snap freezing surgical human tissue specimens exist. At pathology institutes with higher work loads, solid carbon dioxide, freezing sprays, and cryostat freezing are commonly used as coolants for diagnosing frozen tissue sections, whereas for tissue banking, liquid nitrogen or isopentane cooled with liquid nitrogen is preferred. Freezing tissues for diagnostic and research purposes are therefore often time consuming, laborious, even hazardous, and not user friendly. In tissue banks, frozen tissue samples are stored in cryovials, capsules, cryomolds, or cryocassettes. Tissues are additionally embedded using freezing media or wrapped in plastic bags or aluminum foils to prevent desiccation. The latter method aggravates enormously further tissue handling and processing. Here, we describe an isopentane-based workflow which concurrently facilitates tissue freezing and processing for both routine intra-operative frozen section and tissue banking and satisfies the qualitative demands of pathologists, cancer researchers, laboratory technicians, and tissue bankers. PMID:18253747

  7. Perceptions of risk factors of cardiovascular disease and cardiac rehabilitation: a cross-sectional study targeting the Chinese population in the Midlands, UK

    PubMed Central

    Za, Tay; Lau, Jeff C F; Wong, Arthur C K; Wong, Alice W S; Lui, Sally; Fong, James W D; Chow, Patrick Y C; Jolly, Kate B

    2012-01-01

    Objectives To find out and explore the knowledge and opinion of Chinese people on cardiovascular disease and awareness of cardiac rehabilitation. Design A cross-sectional study using 14-item bilingual (Chinese and English) questionnaires that include information on demographics, health status, cardiovascular disease related knowledge and perception, and awareness and understanding of the cardiac rehabilitation programme. Setting Chinese community groups in the Midlands, UK from January to April 2008. Participants 436 questionnaires from Chinese adults over 18 were obtained. Main outcome measures Current knowledge and attitude towards cardiovascular disease and awareness of cardiac rehabilitation. Results Obesity was the most common risk factor identified by 80.7% of participants. Those originated from China had significantly less knowledge compared with subjects from other countries (p<0.001). People who have had exposure or experience of cardiac disease rated a higher risk of cardiac disease for Chinese living in the UK than people without experience. A majority (81.7%) used orthodox medicine and perceived it to be most effective against cardiac disease. Only 30% of participants were aware of cardiac rehabilitation. Conclusion The coronary artery disease (CAD) risk factors of Chinese population have increased significantly in the last decade. Cardiac rehabilitation awareness was poor among the sample population of this study and language barrier is still a problem. More large studies on Chinese population assessing CAD risk should be done to provide more evidence on CAD prevention for this growing population in the Western world. PMID:27326032

  8. Removal of pinned scroll waves in cardiac tissues by electric fields in a generic model of three-dimensional excitable media

    PubMed Central

    Pan, De-Bei; Gao, Xiang; Feng, Xia; Pan, Jun-Ting; Zhang, Hong

    2016-01-01

    Spirals or scroll waves pinned to heterogeneities in cardiac tissues may cause lethal arrhythmias. To unpin these life-threatening spiral waves, methods of wave emission from heterogeneities (WEH) induced by low-voltage pulsed DC electric fields (PDCEFs) and circularly polarized electric fields (CPEFs) have been used in two-dimensional (2D) cardiac tissues. Nevertheless, the unpinning of scroll waves in three-dimensional (3D) cardiac systems is much more difficult than that of spiral waves in 2D cardiac systems, and there are few reports on the removal of pinned scroll waves in 3D cardiac tissues by electric fields. In this article, we investigate in detail the removal of pinned scroll waves in a generic model of 3D excitable media using PDCEF, AC electric field (ACEF) and CPEF, respectively. We find that spherical waves can be induced from the heterogeneities by these electric fields in initially quiescent excitable media. However, only CPEF can induce spherical waves with frequencies higher than that of the pinned scroll wave. Such higher-frequency spherical waves induced by CPEF can be used to drive the pinned scroll wave out of the cardiac systems. We hope this remarkable ability of CPEF can provide a better alternative to terminate arrhythmias caused by pinned scroll waves. PMID:26905367

  9. Removal of pinned scroll waves in cardiac tissues by electric fields in a generic model of three-dimensional excitable media.

    PubMed

    Pan, De-Bei; Gao, Xiang; Feng, Xia; Pan, Jun-Ting; Zhang, Hong

    2016-01-01

    Spirals or scroll waves pinned to heterogeneities in cardiac tissues may cause lethal arrhythmias. To unpin these life-threatening spiral waves, methods of wave emission from heterogeneities (WEH) induced by low-voltage pulsed DC electric fields (PDCEFs) and circularly polarized electric fields (CPEFs) have been used in two-dimensional (2D) cardiac tissues. Nevertheless, the unpinning of scroll waves in three-dimensional (3D) cardiac systems is much more difficult than that of spiral waves in 2D cardiac systems, and there are few reports on the removal of pinned scroll waves in 3D cardiac tissues by electric fields. In this article, we investigate in detail the removal of pinned scroll waves in a generic model of 3D excitable media using PDCEF, AC electric field (ACEF) and CPEF, respectively. We find that spherical waves can be induced from the heterogeneities by these electric fields in initially quiescent excitable media. However, only CPEF can induce spherical waves with frequencies higher than that of the pinned scroll wave. Such higher-frequency spherical waves induced by CPEF can be used to drive the pinned scroll wave out of the cardiac systems. We hope this remarkable ability of CPEF can provide a better alternative to terminate arrhythmias caused by pinned scroll waves. PMID:26905367

  10. Tissue engineering the cardiac microenvironment: Multicellular microphysiological systems for drug screening☆

    PubMed Central

    Kurokawa, Yosuke K.; George, Steven C.

    2016-01-01

    The ability to accurately detect cardiotoxicity has become increasingly important in the development of new drugs. Since the advent of human pluripotent stem cell-derived cardiomyocytes, researchers have explored their use in creating an in vitro drug screening platform. Recently, there has been increasing interest in creating 3D microphysiological models of the heart as a tool to detect cardiotoxic compounds. By recapitulating the complex microenvironment that exists in the native heart, cardiac microphysiological systems have the potential to provide a more accurate pharmacological response compared to current standards in preclinical drug screening. This review aims to provide an overview on the progress made in creating advanced models of the human heart, including the significance and contributions of the various cellular and extracellular components to cardiac function. PMID:26212156

  11. Novel non-isotopic method for the localization of receptors in tissue sections.

    PubMed

    Desnoyers, L; Simonette, R A; Vandlen, R L; Fendly, B M

    2001-12-01

    We describe a novel fluorescent method for the detection of receptors for chimeric proteins in tissue sections. The technique was developed using a recombinant human insulin-like growth factor (IGF-1) chimera, bearing six additional histidine residues at the carboxy-terminal end (IGF-1-His). We demonstrated that dehydration of the tissue sections was detrimental for binding and that its prevention dramatically increased sensitivity. The specificity of IGF-1-His interaction was shown by gradual abolition of the fluorescent signal in the presence of increasing concentrations of IGF-1. Combining immunofluorescence with in situ ligand binding, we showed that IGF-1-His binding corresponded to the IGF-1 receptor (IGFR-1) distribution in human fetal kidney. Moreover, incubation of the tissue sections with an anti-IGFR-1 blocking antibody abolished IGF-1-His binding, demonstrating that the interaction was mediated by the IGFR-1. The method was also used to localize the IGFR-1 in E18 rat embryo sagittal sections. The IGF-1-His binding pattern was observed in brain, cartilage, lung, skin, heart, diaphragm, and tongue, and paralleled the previously reported IGFR-1 distribution. We believe that this new non-isotopic in situ ligand binding method will facilitate rapid and accurate localization of receptors in tissue sections. PMID:11724898

  12. Quantification of hyaluronan and chondroitin/dermatan sulfates in the tissue sections on glass slides.

    PubMed

    Koshiishi, I; Horikoshi, E; Imanari, T

    1999-02-01

    The method for the determination of hyaluronan and chondroitin/dermatan sulfates in the tissue sections on a glass slide, which were prepared by histological technique, was established by applying to porcine skin. The degradation of these glycosaminoglycans to the unsaturated disaccharides in porcine skin sections on a glass slide was achieved by chondroitinase ABC and ACII in the presence of highly purified bacterial collagenase. Subsequently, the resulting unsaturated disaccharides were determined by HPLC with fluorometric postcolumn derivatization using 2-cyanoacetamide as a reagent. So far, the determination of the glycosaminoglycans in the tissues has taken up more than 5 days, whereas the determination of the glycosaminoglycans in the frozen sections by the present method was completed within a day. In addition, applications of the present method to the serial polyester wax sections processed with a small surgical knife made it possible to determine the glycosaminoglycans in a local part in the tissue section. The present method should open a way for the clinical analysis of glycosaminoglycans in the pathological tissue samples. PMID:9918675

  13. Physiological response of cardiac tissue to bisphenol a: alterations in ventricular pressure and contractility

    PubMed Central

    Brooks, Daina; Chandra, Akhil; Jaimes, Rafael; Sarvazyan, Narine; Kay, Matthew

    2015-01-01

    Biomonitoring studies have indicated that humans are routinely exposed to bisphenol A (BPA), a chemical that is commonly used in the production of polycarbonate plastics and epoxy resins. Epidemiological studies have shown that BPA exposure in humans is associated with cardiovascular disease; however, the direct effects of BPA on cardiac physiology are largely unknown. Previously, we have shown that BPA exposure slows atrioventricular electrical conduction, decreases epicardial conduction velocity, and prolongs action potential duration in excised rat hearts. In the present study, we tested if BPA exposure also adversely affects cardiac contractile performance. We examined the impact of BPA exposure level, sex, and pacing rate on cardiac contractile function in excised rat hearts. Hearts were retrogradely perfused at constant pressure and exposed to 10−9-10−4 M BPA. Left ventricular developed pressure and contractility were measured during sinus rhythm and during pacing (5, 6.5, and 9 Hz). Ca2+ transients were imaged from whole hearts and from neonatal rat cardiomyocyte layers. During sinus rhythm in female hearts, BPA exposure decreased left ventricular developed pressure and inotropy in a dose-dependent manner. The reduced contractile performance was exacerbated at higher pacing rates. BPA-induced effects on contractile performance were also observed in male hearts, albeit to a lesser extent. Exposure to BPA altered Ca2+ handling within whole hearts (reduced diastolic and systolic Ca2+ transient potentiation) and neonatal cardiomyocytes (reduced Ca2+ transient amplitude and prolonged Ca2+ transient release time). In conclusion, BPA exposure significantly impaired cardiac performance in a dose-dependent manner, having a major negative impact upon electrical conduction, intracellular Ca2+ handing, and ventricular contractility. PMID:25980024

  14. Simultaneous measurement of cerebral and muscle tissue parameters during cardiac arrest and cardiopulmonary resuscitation

    NASA Astrophysics Data System (ADS)

    Nosrati, Reyhaneh; Ramadeen, Andrew; Hu, Xudong; Woldemichael, Ermias; Kim, Siwook; Dorian, Paul; Toronov, Vladislav

    2015-03-01

    In this series of animal experiments on resuscitation after cardiac arrest we had a unique opportunity to measure hyperspectral near-infrared spectroscopy (hNIRS) parameters directly on the brain dura, or on the brain through the intact pig skull, and simultaneously the muscle hNIRS parameters. Simultaneously the arterial blood pressure and carotid and femoral blood flow were recorded in real time using invasive sensors. We used a novel hyperspectral signalprocessing algorithm to extract time-dependent concentrations of water, hemoglobin, and redox state of cytochrome c oxidase during cardiac arrest and resuscitation. In addition in order to assess the validity of the non-invasive brain measurements the obtained results from the open brain was compared to the results acquired through the skull. The comparison of hNIRS data acquired on brain surface and through the adult pig skull shows that in both cases the hemoglobin and the redox state cytochrome c oxidase changed in similar ways in similar situations and in agreement with blood pressure and flow changes. The comparison of simultaneously measured brain and muscle changes showed expected differences. Overall the results show feasibility of transcranial hNIRS measurements cerebral parameters including the redox state of cytochrome oxidase in human cardiac arrest patients.

  15. Apolipoprotein A-I Mimetic Peptide D-4F Reduces Cardiac Hypertrophy and Improves Apolipoprotein A-I-Mediated Reverse Cholesterol Transport From Cardiac Tissue in LDL Receptor-null Mice Fed a Western Diet.

    PubMed

    Han, Jie; Zhang, Song; Ye, Ping; Liu, Yong-Xue; Qin, Yan-Wen; Miao, Dong-Mei

    2016-05-01

    Epidemiological studies have suggested that hypercholesterolemia is an independent determinant of increased left ventricular (LV) mass. Because high-density lipoprotein and its major protein apolipoprotein A-I (apoA-I) mediate reverse cholesterol transport (RCT) and have cardiac protective effects, we hypothesized that the apoA-I mimetic peptide D-4F could promote RCT in cardiac tissue and decrease cardiac hypertrophy induced by hypercholesterolemia. Low-density lipoprotein receptor-null mice were fed by a Western diet for 18 weeks and then randomized to receive water, or D-4F 0.3 mg/mL, or D-4F 0.5 mg/mL added to drinking water for 6 weeks. After D-4F administration, an increase in high-density lipoprotein cholesterol and a decrease in low-density lipoprotein cholesterol, total cholesterol, and triglyceride in a trend toward dose-responsivity were found in cardiac tissue. Ultrasound biomicroscopy revealed a reduction in LV posterior wall end-diastolic dimension, and an increase in mitral valve E/A ratio and LV ejection fraction. Hematoxylin-eosin staining showed reduced LV wall thickness and myocardial cell diameter. The protein levels of ABCA1 and LXRα were elevated in cardiac tissue of D-4F treated mice compared with the controls (P < 0.05). These results demonstrated that D-4F treatment reduced cardiac hypertrophy, and improved cardiac performance in low-density lipoprotein receptor-null mice fed a Western diet, presumably through the LXRα-ABCA1 pathway associated with enhanced myocardial RCT. PMID:26828321

  16. Mood disturbance and depression in Arab women following hospitalisation from acute cardiac conditions: a cross-sectional study from Qatar

    PubMed Central

    Donnelly, Tam Truong; Al Suwaidi, Jassim Mohd; Al-Qahtani, Awad; Asaad, Nidal; Fung, Tak; Singh, Rajvir; Qader, Najlaa Abdul

    2016-01-01

    Objectives Depression is associated with increased morbidity and mortality rates among cardiovascular patients. Depressed patients have three times higher risk of death than those who are not. We sought to determine the presence of depressive symptoms, and whether gender and age are associated with depression among Arab patients hospitalised with cardiac conditions in a Middle Eastern country. Setting Using a non-probability convenient sampling technique, a cross-sectional survey was conducted with 1000 Arab patients ≥20 years who were admitted to cardiology units between 2013 and 2014 at the Heart Hospital in Qatar. Patients were interviewed 3 days after admission following the cardiac event. Surveys included demographic and clinical characteristics, and the Arabic version of the Beck Depression Inventory Second Edition (BDI-II). Depression was assessed by BDI-II clinical classification scale. Results 15% of the patients had mild mood disturbance and 5% had symptoms of clinical depression. Twice as many females than males suffered from mild mood disturbance and clinical depression symptoms, the majority of females were in the age group 50 years and above, whereas males were in the age group 40–49 years. χ2 Tests and multivariate logistic regression analyses indicated that gender and age were statistically significantly related to depression (p<0.001 for all). Conclusions Older Arab women are more likely to develop mood disturbance and depression after being hospitalised with acute cardiac condition. Gender and age differences approach, and routine screening for depression should be conducted with all cardiovascular patients, especially for females in the older age groups. Mental health counselling should be available for all cardiovascular patients who exhibit depressive symptoms. PMID:27388362

  17. Three dimensional dual labelled DNA fluorescent in situ hybridization analysis in fixed tissue sections

    PubMed Central

    Kernohan, Kristin D.; Bérubé, Nathalie G.

    2014-01-01

    Emerging studies demonstrate that three-dimensional organization of chromatin in the nucleus plays a vital role in regulating the genome. DNA fluorescent in situ hybridization (FISH) is a common molecular technique used to visualize the location of DNA sequences. The vast majority of DNA FISH studies are conducted on cultured cells due to the technical difficulties encountered using fixed tissue sections. However, the use of cultured cells poses important limitations that could yield misleading results, making in vivo analysis a far superior approach. Here we present a protocol for multiplexed three dimensional DNA FISH in mouse brain sections, which is also applicable to other tissues. Paraffin-embedded tissues could be used but the embedding and preparation of the samples is time-consuming and often associated with poor antigenicity. To overcome this problem we:•developed a FISH technique using fixed, frozen cryosections;•provide specific instructions for tissue processing for proper fixation and freezing, including equilibration in sucrose gradients to maintain proper cellular structure;•include optimized permeabilization and washing steps to achieve specific signal and to limit background fluorescence in tissue sections. PMID:26150931

  18. IR-MALDESI MASS SPECTROMETRY IMAGING OF BIOLOGICAL TISSUE SECTIONS USING ICE AS A MATRIX

    PubMed Central

    Robichaud, Guillaume; Barry, Jeremy A.; Muddiman, David C.

    2014-01-01

    Infrared Matrix-Assisted Laser Desorption Electrospray Ionization (IR-MALDESI) Mass Spectrometry imaging of biological tissue sections using a layer of deposited ice as an energy absorbing matrix was investigated. Dynamics of plume ablation were first explored using a nanosecond exposure shadowgraphy system designed to simultaneously collect pictures of the plume with a camera and collect the FT-ICR mass spectrum corresponding to that same ablation event. Ablation of fresh tissue analyzed with and without using ice as a matrix were both compared using this technique. Effect of spot-to-spot distance, number of laser shots per pixel and tissue condition (matrix) on ion abundance was also investigated for 50 µm thick tissue sections. Finally, the statistical method called design of experiments was used to compare source parameters and determine the optimal conditions for IR-MALDESI of tissue sections using deposited ice as a matrix. With a better understanding of the fundamentals of ablation dynamics and a systematic approach to explore the experimental space, it was possible to improve ion abundance by nearly one order of magnitude. PMID:24385399

  19. Electrospun type 1 collagen matrices preserving native ultrastructure using benign binary solvent for cardiac tissue engineering.

    PubMed

    Elamparithi, Anuradha; Punnoose, Alan M; Kuruvilla, Sarah

    2016-08-01

    Electrospinning is a well-established technique that uses a high electric field to fabricate ultrafine fibrous scaffolds from both natural and synthetic polymers to mimic the cellular microenvironment. Collagen is one of the most preferred biopolymers, due to its widespread occurrence in nature and its biocompatibility. Electrospinning of collagen alone has been reported, with fluoroalcohols such as hexafluoroisopropanol (HFIP) and trifluoroethanol (TFE), but the resultant collagen lost its characteristic ultrastructural integrity of D-periodicity 67 nm banding, confirmed by transmission electron microscopy (TEM), and the fluoroalcohols used were toxic to the environment. In this study, we describe the use of glacial acetic acid and DMSO to dissolve collagen and generate electrospun nanofibers of collagen type 1, which is non-toxic and economical. TEM analysis revealed the characteristic feature of native collagen triple helical repeats, showing 67 nm D-periodicity banding pattern and confirming that the ultrastructural integrity of the collagen was maintained. Analysis by scanning electron microscopy (SEM) showed fiber diameters in the range of 200-1100 nm. Biocompatibility of the three-dimensional (3D) scaffolds was established by MTT assays using rat skeletal myoblasts (L6 cell line) and confocal microscopic analysis of immunofluorescent-stained sections of collagen scaffolds for muscle-specific markers such as desmin and actin. Primary neonatal rat ventricular cardiomyocytes (NRVCM) seeded onto the collagen scaffolds were able to maintain their contractile function for a period of 17 days and also expressed higher levels of desmin when compared with 2D cultures. We report for the first time that collagen type 1 can be electrospun without blending with copolymers using the novel benign solvent combination, and the method can be potentially explored for applications in tissue engineering. PMID:25960178

  20. Multimodal Mass Spectrometry Imaging of N-Glycans and Proteins from the Same Tissue Section.

    PubMed

    Heijs, Bram; Holst, Stephanie; Briaire-de Bruijn, Inge H; van Pelt, Gabi W; de Ru, Arnoud H; van Veelen, Peter A; Drake, Richard R; Mehta, Anand S; Mesker, Wilma E; Tollenaar, Rob A; Bovée, Judith V M G; Wuhrer, Manfred; McDonnell, Liam A

    2016-08-01

    On-tissue digestion matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) can be used to record spatially correlated molecular information from formalin-fixed, paraffin-embedded (FFPE) tissue sections. In this work, we present the in situ multimodal analysis of N-linked glycans and proteins from the same FFPE tissue section. The robustness and applicability of the method are demonstrated for several tumors, including epithelial and mesenchymal tumor types. Major analytical aspects, such as lateral diffusion of the analyte molecules and differences in measurement sensitivity due to the additional sample preparation methods, have been investigated for both N-glycans and proteolytic peptides. By combining the MSI approach with extract analysis, we were also able to assess which mass spectral peaks generated by MALDI-MSI could be assigned to unique N-glycan and peptide identities. PMID:27373711

  1. Chemical modification of carbohydrates in tissue sections may unmask mucin antigens.

    PubMed

    Kirkeby, S

    2013-01-01

    Expression of mucins in cells and tissues is of great diagnostic and prognostic importance, and immunohistochemistry frequently is used to detect them. Reports concerning mucin localization in sections sometimes are conflicting, however, partly because immunogenic regions of the mucin molecule may be masked and thus not available for binding to an antibody. We modified carbohydrates in tissue sections chemically to enhance the binding of monoclonal mucin antibodies and of the lectin, Vicia villosa B4, to human tissue. The immunohistochemical localization of MUC1 and the simple mucin-type antigens, Tn and sialyl-Tn, was influenced by oxidation with periodic acid and by β-elimination before incubation. In some epithelial cells the staining was prevented by these procedures while in other cells it was evident. It appears that chemical modification can either destroy some antigen binding sites or unmask cryptic antigen binding sites in the mucin molecule and thereby make them accessible for immunohistochemical detection. PMID:22998734

  2. Changes in chromatin structure during processing of wax-embedded tissue sections

    PubMed Central

    Kerr, Elizabeth; Kiyuna, Tomoharu; Boyle, Shelagh; Saito, Akira; Thomas, Jeremy St J.

    2010-01-01

    The use of immunofluorescence (IF) and fluorescence in situ hybridisation (FISH) underpins much of our understanding of how chromatin is organised in the nucleus. However, there has only recently been an appreciation that these types of study need to move away from cells grown in culture and towards an investigation of nuclear organisation in cells in situ in their normal tissue architecture. Such analyses, however, especially of archival clinical samples, often requires use of formalin-fixed paraffin wax-embedded tissue sections which need addition steps of processing prior to IF or FISH. Here we quantify the changes in nuclear and chromatin structure that may be caused by these additional processing steps. Treatments, especially the microwaving to reverse fixation, do significantly alter nuclear architecture and chromatin texture, and these must be considered when inferring the original organisation of the nucleus from data collected from wax-embedded tissue sections. PMID:20661639

  3. Pre-treatment of synthetic elastomeric scaffolds by cardiac fibroblasts improves engineered heart tissue.

    PubMed

    Radisic, Milica; Park, Hyoungshin; Martens, Timothy P; Salazar-Lazaro, Johanna E; Geng, Wenliang; Wang, Yadong; Langer, Robert; Freed, Lisa E; Vunjak-Novakovic, Gordana

    2008-09-01

    Native myocardium consists of several cell types, of which approximately one-third are myocytes and most of the nonmyocytes are fibroblasts. By analogy with monolayer culture in which fibroblasts were removed to prevent overgrowth, early attempts to engineer myocardium utilized cell populations enriched for cardiac myocytes (CMs; approximately 80-90% of total cells). We hypothesized that the pre-treatment of synthetic elastomeric scaffolds with cardiac fibroblasts (CFs) will enhance the functional assembly of the engineered cardiac constructs by creating an environment supportive of cardiomyocyte attachment and function. Cells isolated from neonatal rat ventricles were prepared to form three distinct populations: rapidly plating cells identified as CFs, slowly plating cells identified as CMs, and unseparated initial population of cells (US). The cell fractions (3 x 10(6) cells total) were seeded into poly(glycerol sebacate) scaffolds (highly porous discs, 5 mm in diameter x 2-mm thick) using Matrigeltrade mark, either separately (CM or CF), concurrently (US), or sequentially (CF pre-treatment followed by CM culture, CF + CM), and cultured in spinner flasks. The CF + CM group had the highest amplitude of contraction and the lowest excitation threshold, superior DNA content, and higher glucose consumption rate. The CF + CM group exhibited compact 100- to 200-mum thick layers of elongated myocytes aligned in parallel over layers of collagen-producing fibroblasts, while US and CM groups exhibited scattered and poorly elongated myocytes. The sequential co-culture of CF and CM on a synthetic elastomer scaffold thus created an environment supportive of cardiomyocyte attachment, differentiation, and contractile function, presumably due to scaffold conditioning by cultured fibroblasts. When implanted over the infarcted myocardium in a nude rat model, cell-free poly(glycerol sebacate) remained at the ventricular wall after 2 weeks of in vivo, and was vascularized. PMID

  4. Multi-parametric MRI as an indirect evaluation tool of the mechanical properties of in-vitro cardiac tissues

    PubMed Central

    2013-01-01

    Background Early detection of heart failure is essential to effectively reduce related mortality. The quantification of the mechanical properties of the myocardium, a primordial indicator of the viability of the cardiac tissue, is a key element in patient’s care. Despite an incremental utilization of multi-parametric magnetic resonance imaging (MRI) for cardiac tissue characteristics and function, the link between multi-parametric MRI and the mechanical properties of the heart has not been established. We sought to determine the parametric relationship between the myocardial mechanical properties and the MR parameters. The specific aim was to develop a reproducible evaluative quantitative tool of the mechanical properties of cardiac tissue using multi-parametric MRI associated to principal component analysis. Methods Samples from porcine hearts were submitted to a multi-parametric MRI acquisition followed by a uniaxial tensile test. Multi linear regressions were performed between dependent (Young’s modulus E) and independent (relaxation times T1, T2 and T2*, magnetization transfer ratio MTR, apparent diffusion coefficient ADC and fractional anisotropy FA) variables. A principal component analysis was used to convert the set of possibly correlated variables into a set of linearly uncorrelated variables. Results Values of 46.1±12.7 MPa for E, 729±21 ms for T1, 61±6 ms for T2, 26±7 for T2*, 35±5% for MTRx100, 33.8±4.7 for FAx10-2, and 5.85±0.21 mm2/s for ADCx10-4 were measured. Multi linear regressions showed that only 45% of E can be explained by the MRI parameters. The principal component analysis reduced our seven variables to two principal components with a cumulative variability of 63%, which increased to 80% when considering the third principal component. Conclusions The proposed multi-parametric MRI protocol associated to principal component analysis is a promising tool for the evaluation of mechanical properties within the left ventricle in the

  5. In vitro chick pre-cardiac explant tissue differentiation during spaceflight on SpaceHab-02

    NASA Technical Reports Server (NTRS)

    van Twest, J. S.; Paulsen, A.; Spooner, B. S.

    1995-01-01

    Chick precardiac tissue explants were cultured on the 8-day mission of STS-60, space shuttle Discovery. Development of in vitro cultures of precardiac chick tissue from embryo stages 5 though 8 (H-H) were initiated during orbit and were terminated after approximately fifteen hours of 37 degree C culture. Transmission electron microscopy and tritiated thymidine studies were performed postflight. No significant differences in cell proliferation were observed between flight and ground controls. Electron-microscopic studies revealed stage 8 explants were capable of differentiation during flight in a pattern which matched ground control tissues. As anticipated, stage 7 explant tissues had differentiated to a lesser extent compared to stage 8 tissues. Interestingly, stage 7 precardiac explant flight tissue differentiation was less than ground control tissue. This difference in differentiation between flight and ground cultures was enhanced in stage 6 tissues, as high levels of myofibril organization were only seen in ground controls. Other cellular components such as Golgi apparatus, junctional complexes, and mitochondria were present and appeared normal and healthy.

  6. mTOR Complexes Repress Hypertrophic Agonist-Stimulated Expression of Connective Tissue Growth Factor in Adult Cardiac Muscle Cells.

    PubMed

    Sundararaj, Kamala; Pleasant, Dorea L; Moschella, Phillip C; Panneerselvam, Kavin; Balasubramanian, Sundaravadivel; Kuppuswamy, Dhandapani

    2016-02-01

    Connective tissue growth factor (CTGF) is a fibrogenic cytokine that promotes fibrosis in various organs. In the heart, both cardiomyocytes (CM) and cardiac fibroblasts have been reported as a source of CTGF expression, aiding cardiac fibrosis. Although the mammalian target of rapamycin (mTOR) forms 2 distinct complexes, mTORC1 and mTORC2, and plays a central role in integrating biochemical signals for protein synthesis and cellular homeostasis, we explored its role in CTGF expression in adult feline CM. CM were stimulated with 10 μM phenylephrine (PE), 200 nM angiotensin (Ang), or 100 nM insulin for 24 hours. PE and Ang, but not insulin, caused an increase in CTGF mRNA expression with the highest expression observed with PE. Inhibition of mTOR with torin1 but not rapamycin significantly enhanced PE-stimulated CTGF expression. Furthermore, silencing of raptor and rictor using shRNA adenoviral vectors to suppress mTORC1 and mTORC2, respectively, or blocking phosphatidylinositol 3-kinase (PI3K) signaling with LY294002 (LY) or Akt signaling by dominant-negative Akt expression caused a substantial increase in PE-stimulated CTGF expression as measured by both mRNA and secreted protein levels. However, studies with dominant-negative delta isoform of protein kinase C demonstrate that delta isoform of protein kinase C is required for both agonist-induced CTGF expression and mTORC2/Akt-mediated CTGF suppression. Finally, PE-stimulated CTGF expression was accompanied with a corresponding increase in Smad3 phosphorylation and pretreatment of cells with SIS3, a Smad3 specific inhibitor, partially blocked the PE-stimulated CTGF expression. Therefore, a PI3K/mTOR/Akt axis plays a suppressive role on agonist-stimulated CTGF expression where the loss of this mechanism could be a contributing factor for the onset of cardiac fibrosis in the hypertrophying myocardium. PMID:26371948

  7. Morphological segmentation of multiprobe fluorescence images for immunophenotyping in melanoma tissue sections

    NASA Astrophysics Data System (ADS)

    Dow, Alasdair I.; Shafer, Steven A.; Waggoner, Alan S.

    1993-08-01

    A fundamental task in studying the action of cancer chemotherapy is to determine the quantity and spatial relationship of tumor-infiltrating lymphocyte populations. Classically this is performed by staining thin tissue sections with antibodies by immunoperoxidase amplification. The staining technique is practically limited to locating a single cell type per tissue section. Full immunophenotyping requires successive staining of serial sections, using statistical analysis to correlate the results. This paper describes a system that brings together multi- parameter fluorescence imaging and morphological segmentation techniques to provide a fast, accurate, and automatic analysis of the lymphocyte infiltrate in tissue sections. With fluorescence techniques a single section can be stained with up to four distinct fluorescently labelled antibodies to determine cell phenotypes. To harness this potential computer vision techniques are required to analyze the images. A routine based on the water shed algorithm has been developed that segments the nuclei image with an accuracy of greater than 90%. By matching the nuclei boundaries to the local peak fluorescence, cell boundary estimates are obtained in the antigen images. By then extracting two measurements from the boundary signal the cells can be classified according to their antigen expression. Determining cell expression of multiple antigens simultaneously provides a more detailed and accurate picture of the tumor infiltrate than single parameter analysis, and increases understanding of the immune response associated with the chemotherapy.

  8. The Responses of Tissues from the Brain, Heart, Kidney, and Liver to Resuscitation following Prolonged Cardiac Arrest by Examining Mitochondrial Respiration in Rats

    PubMed Central

    Kim, Junhwan; Perales Villarroel, José Paul; Zhang, Wei; Yin, Tai; Shinozaki, Koichiro; Hong, Angela; Lampe, Joshua W.; Becker, Lance B.

    2016-01-01

    Cardiac arrest induces whole-body ischemia, which causes damage to multiple organs. Understanding how each organ responds to ischemia/reperfusion is important to develop better resuscitation strategies. Because direct measurement of organ function is not practicable in most animal models, we attempt to use mitochondrial respiration to test efficacy of resuscitation on the brain, heart, kidney, and liver following prolonged cardiac arrest. Male Sprague-Dawley rats are subjected to asphyxia-induced cardiac arrest for 30 min or 45 min, or 30 min cardiac arrest followed by 60 min cardiopulmonary bypass resuscitation. Mitochondria are isolated from brain, heart, kidney, and liver tissues and examined for respiration activity. Following cardiac arrest, a time-dependent decrease in state-3 respiration is observed in mitochondria from all four tissues. Following 60 min resuscitation, the respiration activity of brain mitochondria varies greatly in different animals. The activity after resuscitation remains the same in heart mitochondria and significantly increases in kidney and liver mitochondria. The result shows that inhibition of state-3 respiration is a good marker to evaluate the efficacy of resuscitation for each organ. The resulting state-3 respiration of brain and heart mitochondria following resuscitation reenforces the need for developing better strategies to resuscitate these critical organs following prolonged cardiac arrest. PMID:26770657

  9. Management of cardiac arrest in a parturient with Eisenmenger's syndrome and complete atrioventricular block during Cesarean section: a case report

    PubMed Central

    Kim, Gaab Soo; Chang, Choo Hoon; Lee, Eun Kyung; Choi, Jeong Yeon

    2015-01-01

    A 26-year-old parturient with Eisenmenger's syndrome and complete atrioventricular block was presented for emergency Cesarean section due to preterm labor. Ventricular tachycardia (VT), which progressed to ventricular fibrillation (VF), started immediately after the incision. Cardiopulmonary resuscitation with electric shocks was given by anesthesiologists while the obstetrician delivered the baby between the shocks. A cardiac surgeon was ready for extracorporeal membrane oxygenation institution in case of emergency but spontaneous circulation of the patient returned after the 3rd shock and the delivery of the baby. The newborn's Apgar score was 4 at 1 minute and 8 at 5 minutes. An implantable cardioverter-defibrillator was inserted before the discharge because the patient had recurrent episodes of VT and VF postoperatively. PMID:26634088

  10. Estimation of cardiac conductivities in ventricular tissue by a variational approach

    NASA Astrophysics Data System (ADS)

    Yang, Huanhuan; Veneziani, Alessandro

    2015-11-01

    The bidomain model is the current standard model to simulate cardiac potential propagation. The numerical solution of this system of partial differential equations strongly depends on the model parameters and in particular on the cardiac conductivities. Unfortunately, it is quite problematic to measure these parameters in vivo and even more so in clinical practice, resulting in no common agreement in the literature. In this paper we consider a variational data assimilation approach to estimating those parameters. We consider the parameters as control variables to minimize the mismatch between the computed and the measured potentials under the constraint of the bidomain system. The existence of a minimizer of the misfit function is proved with the phenomenological Rogers-McCulloch ionic model, that completes the bidomain system. We significantly improve the numerical approaches in the literature by resorting to a derivative-based optimization method with settlement of some challenges due to discontinuity. The improvement in computational efficiency is confirmed by a 2D test as a direct comparison with approaches in the literature. The core of our numerical results is in 3D, on both idealized and real geometries, with the minimal ionic model. We demonstrate the reliability and the stability of the conductivity estimation approach in the presence of noise and with an imperfect knowledge of other model parameters.

  11. A sensitive algorithm for automatic detection of space-time alternating signals in cardiac tissue

    PubMed Central

    Bien, Harold; Entcheva, Emilia

    2011-01-01

    Alternans, a beat-to-beat alternation in cardiac signals, may serve as a precursor to lethal cardiac arrhythmias, including ventricular tachycardia and ventricular fibrillation. Therefore, alternans is a desirable target of early arrhythmia prediction/detection. For long-term records and in the presence of noise, the definition of alternans is qualitative and ambiguous. This makes their automatic detection in large spatiotemporal data sets almost impossible. We present here a quantitative combinatorics-derived definition of alternans in the presence of random noise and a novel algorithm for automatic alternans detection using criteria like temporal persistence (TP), representative phase (RP) and alternans ratio (AR). This technique is validated by comparison to theoretically-derived probabilities and by test data sets with white noise. Finally, the algorithm is applied to ultra-high resolution optical mapping data from cultured cell monolayers, exhibiting calcium alternans. Early fine-scale alternans, close to the noise level, were revealed and linked to the later formation of larger regions and evolution of spatially discordant alternans (SDA). This robust new technique can be useful in quantification and better understanding of the onset of arrhythmias and in general analysis of space-time alternating signals. PMID:19162616

  12. Evaluation of Cardiac Autonomic Functions in Older Parkinson's Disease Patients: a Cross-Sectional Study.

    PubMed

    Yalcin, Ahmet; Atmis, Volkan; Cengiz, Ozlem Karaarslan; Cinar, Esat; Aras, Sevgi; Varli, Murat; Atli, Teslime

    2016-01-01

    In Parkinson's disease (PD), non-motor symptoms may occur such as autonomic dysfunction. We aimed to evaluate both parasympathetic and sympathetic cardiovascular autonomic dysfunction in older PD cases. 84 PD cases and 58 controls, for a total of 142, participated in the study. Parasympathetic tests were performed using electrocardiography. Sympathetic tests were assessed by blood pressure measurement and 24-hour ambulatory blood pressure measurement. The prevalence of orthostatic hypotension in PD patients was 40.5% in PD patients and 24.1% in the control group (p> 0.05). The prevalence of postprandial hypotension was 47.9% in the PD group and 27.5% in the controls (p <0.05). The prevalence of impairment in heart rate response to deep breathing was 26.2% in the PD group and 6.9% in the control group (p <0.05). The prevalence of postprandial hypotension in PD with orthostatic hypotension was 94% and 16% in PD patients without orthostatic hypotension (p <0.05). The prevalence of impairment in heart rate response to deep breathing was 52.9% in PD patients with orthostatic hypotension and 8% in PD cases without orthostatic hypotension (p<0.05). The prevalence of impairment in heart rate response to postural change was 41% in PD cases with orthostatic hypotension and 12% in PD cases without orthostatic hypotension (p <0.05).Although there are tests for assessing cardiovascular autonomic function that are more reliable, they are more complicated, and evaluation of orthostatic hypotension by blood pressure measurement and cardiac autonomic tests by electrocardiography are recommended since these tests are cheap and easy. PMID:26816661

  13. Intracellular pH in Gastric and Rectal Tissue Post Cardiac Arrest

    NASA Astrophysics Data System (ADS)

    Fisher, Elaine M.; Steiner, Richard P.; LaManna, Joseph C.

    We directly measured pHi using the pH sensitive dye, neutral red. We defined pHi for rectal and gastric tissue in whole tissue and by layer under control and arrest conditions. Fifteen minutes of arrest was not sufficient time to alter the pHi at the rectal or gastric site. On initial inspection, the stomach may be more sensitive to ischemic changes than the rectum. Understanding the mechanism by which PCO2 generation is used to track clinical changes is vital to the early detection of tissue dysoxia in order to effectively treat and manage critically ill patients.

  14. FROZEN THIN SECTIONS OF FRESH TISSUE FOR ELECTRON MICROSCOPY, WITH A DESCRIPTION OF PANCREAS AND LIVER

    PubMed Central

    Christensen, A. Kent

    1971-01-01

    A simple method has been developed that allows frozen thin sections of fresh-frozen tissue to be cut on a virtually unmodified ultramicrotome kept at room temperature. A bowl-shaped Dewar flask with a knifeholder in its depths replaces the stage of the microtome; a bar extends down into the bowl from the microtome's cutting arm and bears the frozen tissue near its lower end. When the microtome is operated, the tissue passes a glass or diamond knife in the depths of the bowl as in normal cutting. The cutting temperature is maintained by flushing the bowl with cold nitrogen gas, and can be set anywhere from about -160°C up to about -30°C. The microtome is set for a cutting thickness of 540–1000 A. Sections are picked up from the dry knife edge, and are placed on membrane-coated grids, flattened with the polished end of a copper rod, and either dried in nitrogen gas or freeze-dried. Throughout the entire process the tissue is kept cold and does not come in contact with any solvent. The morphology seen in frozen thin sections of rat pancreas and liver generally resembles that in conventional preparations, although freezing damage and low contrast limit the detail that can be discerned. Among unusual findings is a frequent abundance of mitochondrial granules in material prepared by this method. PMID:4942776

  15. Hyperspectral unmixing for removing autofluorescence from paraffin-embedded formalin-fixed tissue sections

    NASA Astrophysics Data System (ADS)

    Constantinou, P.; Wilson, B. C.; Damaskinos, S.

    2005-09-01

    The use of digital fluorescence confocal microscopy in biological sciences has grown in recent decades due to the versatility of fluorescence imaging. The ability to selectively label specific morphological features, genetic mutations and/or chemical micro-environmental changes with discreet fluorescent labels allows a better understanding of the complex systems that regulate cellular processes. Specimens can range in size from single cells to tissue sections and tissue arrays, which can occupy the entire surface of a microscope slide (25mm x 70mm). Using a confocal scanning laser MACROscope, a wide-area confocal imaging system (Biomedical Photometrics Inc.), it is possible to image these large specimens at high resolution, without the need to tile many small microscope fields. A hyperspectral imaging (HSI) mode has been added to the MACROscope system to assess the use of HSI in the removal/separation of tissue autofluorescence from digital images of fluorescently-labeled paraffin-embedded, formalin-fixed tissue sections. In pathology and immunohistochemistry applications this autofluorescence can hinder, or even prevent, detection of the applied fluorescent label(s). In the present study, fluorescence emission from the specimen was sampled at ~7 nm bandwidths across 32 channels, amounting to viewing ~220 nm of the visible spectrum as a hyperspectral data cube. The data cube was then processed to remove the contributions from autofluorescence, leaving only the signal from the fluorophore(s) of interest. Comparisons are drawn from HSI obtained with a commercial hyperspectral confocal microscope (Zeiss LSM 510 META) employing image tiling. The initial results demonstrate the ability to spectrally unmix the tissue autofluorescence in large tissue sections.

  16. Sulfated levan from Halomonas smyrnensis as a bioactive, heparin-mimetic glycan for cardiac tissue engineering applications.

    PubMed

    Erginer, Merve; Akcay, Ayca; Coskunkan, Binnaz; Morova, Tunc; Rende, Deniz; Bucak, Seyda; Baysal, Nihat; Ozisik, Rahmi; Eroglu, Mehmet S; Agirbasli, Mehmet; Toksoy Oner, Ebru

    2016-09-20

    Chemical derivatives of levan from Halomonas smyrnensis AAD6(T) with low, medium and high levels of sulfation were synthesized and characterized by FTIR and 2D-NMR. Sulfated levan samples were found to exhibit anticoagulation activity via the intrinsic pathway like heparin in a dose-dependent manner. Exceptionally high heparin equivalent activity of levan sulfate was shown to proceed via thrombin inhibition where decreased Factor Xa activity with increasing concentration was observed in antithrombin tests and above a certain concentration, levan sulfate showed a better inhibitor activity than heparin. In vitro experimental results were then verified in silico by docking studies using equilibrium structures obtained by molecular dynamic simulations and results suggested a sulfation dependent binding mechanism. With its high biocompatibility and heparin mimetic activity, levan sulfate can be considered as a suitable functional biomaterial to design biologically active, functionalized, thin films and engineered smart scaffolds for cardiac tissue engineering applications. PMID:27261753

  17. Compound and metabolite distribution measured by MALDI mass spectrometric imaging in whole-body tissue sections

    NASA Astrophysics Data System (ADS)

    Stoeckli, Markus; Staab, Dieter; Schweitzer, Alain

    2007-02-01

    The determination of the compound distribution in laboratory animal tissue in early development is a standard process in pharmaceutical research. While this information is traditionally obtained by means of whole-body autoradiography using radiolabeled compounds, this technology does not distinguish between metabolites and parent compound. The technique described in this article, termed matrix-assisted laser desorption/ionization (MALDI) mass spectrometric imaging, can fill this gap by simultaneously measuring compound and multiple metabolites distributed in whole-body tissue sections, using non-labeled compounds.

  18. Proliferation Assays (BrdU and EdU) on Skeletal Tissue Sections

    PubMed Central

    Mead, Timothy J.; Lefebvre, Véronique

    2014-01-01

    Assessing cell proliferation in situ is an important phenotyping component of skeletal tissues from development to adult stages and disease. Various methods exist including immunostaining for proteins and protein modifications associated with specific steps of the cell cycle, but the gold standard is to quantify the percentage of DNA-synthesizing cells. The thymidine analog 5-bromo-2′-deoxyuridine (BrdU) has been widely used in the last decades for this purpose, with the inconvenience that its detection is lengthy and requires harsh treatment of tissue sections to give access of anti-BrdU antibody to nucleosides in genomic DNA. In 2008, Salic and Mitchison developed a new method and proved it to be quicker, simpler, and highly sensitive in non-skeletal tissues. This method relies on incorporation of 5-ethynyl-2′-deoxyuridine (EdU) into de novo DNA. This other thymidine analog is readily detected by click chemistry, i.e., covalent cross-linking of its ethynyl group with a fluorescent azide, a molecule small enough to diffuse freely through native tissues and DNA. Here, we describe and compare the BrdU and EdU approaches in skeletal tissues and conclude that in these tissues too EdU provides an easy and very sensitive alternative to BrdU. PMID:24482177

  19. Proliferation assays (BrdU and EdU) on skeletal tissue sections.

    PubMed

    Mead, Timothy J; Lefebvre, Véronique

    2014-01-01

    Assessing cell proliferation in situ is an important phenotyping component of skeletal tissues from development to adult stages and disease. Various methods exist including immunostaining for proteins and protein modifications associated with specific steps of the cell cycle, but the gold standard is to quantify the percentage of DNA-synthesizing cells. The thymidine analog 5-bromo-2'-deoxyuridine (BrdU) has been widely used in the last decades for this purpose, with the inconvenience that its detection is lengthy and requires harsh treatment of tissue sections to give access of anti-BrdU antibody to nucleosides in genomic DNA. In 2008, Salic and Mitchison developed a new method and proved it to be quicker, simpler, and highly sensitive in non-skeletal tissues. This method relies on incorporation of 5-ethynyl-2'-deoxyuridine (EdU) into de novo DNA. This other thymidine analog is readily detected by click chemistry, i.e., covalent cross-linking of its ethynyl group with a fluorescent azide, a molecule small enough to diffuse freely through native tissues and DNA. Here, we describe and compare the BrdU and EdU approaches in skeletal tissues and conclude that in these tissues too EdU provides an easy and very sensitive alternative to BrdU. PMID:24482177

  20. Synchronization of early afterdepolarizations and arrhythmogenesis in heterogeneous cardiac tissue models.

    PubMed

    de Lange, Enno; Xie, Yuanfang; Qu, Zhilin

    2012-07-18

    Early afterdepolarizations (EADs) are linked to both triggered arrhythmias and reentrant arrhythmias by causing premature ventricular complexes (PVCs), focal excitations, or heterogeneous tissue substrates for reentry formation. However, a critical number of cells that synchronously exhibit EADs are needed to result in arrhythmia triggers and substrates in tissue. In this study, we use mathematical modeling and computer simulations to investigate EAD synchronization and arrhythmia induction in tissue models with random cell-to-cell variations. Our major observations are as follows. Random cell-to-cell variations in action potential duration without EAD presence do not cause large dispersion of refractoriness in well-coupled tissue. In the presence of phase-2 EADs, the cells may synchronously exhibit the same number of EADs or no EADs with a very small dispersion of refractoriness, or synchronize regionally to result in large dispersion of refractoriness. In the presence of phase-3 EADs, regional synchronization leads to propagating EADs, forming PVCs in tissue. Interestingly, even though the uncoupled cells exhibit either no EAD or only a single EAD, when these cells are coupled to form a tissue, more than one PVC can occur. When the PVCs occur at different locations and time, multifocal arrhythmias are triggered, with the foci shifting in space and time in an irregular manner. The focal arrhythmias either spontaneously terminate or degenerate into reentrant arrhythmias due to heterogeneities and spatiotemporal chaotic dynamics of the foci. PMID:22853915

  1. Automatic segmentation of histological structures in normal and neoplastic mammary gland tissue sections

    SciTech Connect

    Fernandez-Gonzalez, Rodrigo; Deschamps, Thomas; Idica, Adam K.; Malladi, Ravi; Ortiz de Solorzano, Carlos

    2003-01-18

    In this paper we present a scheme for real time segmentation of histological structures in microscopic images of normal and neoplastic mammary gland sections. Paraffin embedded or frozen tissue blocks are sliced, and sections are stained with hematoxylin and eosin (H&E). The sections are then imaged using conventional bright field microscopy. The background of the images is corrected by arithmetic manipulation using a ''phantom.'' Then we use the fast marching method with a speed function that depends on the brightness gradient of the image to obtain a preliminary approximation to the boundaries of the structures of interest within a region of interest (ROI) of the entire section manually selected by the user. We use the result of the fast marching method as the initial condition for the level set motion equation. We run this last method for a few steps and obtain the final result of the segmentation. These results can be connected from section to section to build a three-dimensional reconstruction of the entire tissue block that we are studying.

  2. Automatic segementation of histological structures in normal and neoplastic mammary gland tissue sections

    NASA Astrophysics Data System (ADS)

    Fernandez-Gonzalez, Rodrigo; Deschamps, Thomas; Idica, Adam; Malladi, Ravikanth; Ortiz de Solorzano, Carlos

    2003-07-01

    In this paper we present a scheme for real time segmentation of histological structures in microscopic images of normal and neoplastic mammary gland sections. Paraffin embedded or frozen tissue blocks are sliced, and sections are stained with hematoxylin and eosin (H&E). The sections are then imaged using conventional bright field microscopy. The background of the images is corrected by arithmetic manipulation using a "phantom." Then we use the fast marching method with a speed function that depends on the brightness gradient of the image to obtain a preliminary approximation to the boundaries of the structures of interest within a region of interest (ROI) of the entire section manually selected by the user. We use the result of the fast marching method as the initial condition for the level set motion equation. We run this last method for a few steps and obtain the final result of the segmentation. These results can be connected from section to section to build a three-dimensional reconstruction of the entire tissue block that we are studying.

  3. [Time costs cardiac muscle tissue--prehospital therapy of acute myocardial infarct--a case report].

    PubMed

    Eschenburg, G; Pappert, D; Ohlmeier, H

    2003-01-01

    Symptoms of an acute myocardial infarction are a common reason for calling the emergency physician. Pre-hospital mortality caused by cardiac infarction is constantly high. The main potential for decreasing infarction mortality lies in the pre-hospital period. The problems and prospects of treatment in the early period are described in the case of a 73-year-old patient with an acute anterior infarction. The diagnostic and therapeutic approach is shown and discussed in this concrete case, taking into consideration the guidelines for diagnostics and therapy of acute myocardial infarction in the pre-hospital period of the German Society for Cardiology. A particular focus is the management of pre-hospital thrombolysis, the preconditions, realization and risks of which are described. In this context, the experience and competence of the emergency physician is prerequisite for the exact diagnosis and therapy. Furthermore, the importance of a smooth transition from pre-hospital therapy to intensive care is emphasized. PMID:12666508

  4. Real-time optical monitoring of permanent lesion progression in radiofrequency ablated cardiac tissue (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Singh-Moon, Rajinder P.; Hendon, Christine P.

    2016-02-01

    Despite considerable advances in guidance of radiofrequency ablation (RFA) therapies for atrial fibrillation, success rates have been hampered by an inability to intraoperatively characterize the extent of permanent injury. Insufficient lesions can elusively create transient conduction blockages that eventually reconduct. Prior studies suggest significantly greater met-myoglobin (Mmb) concentrations in the lesion core than those in the healthy myocardium and may serve as a marker for irreversible tissue damage. In this work, we present real-time monitoring of permanent injury through spectroscopic assessment of Mmb concentrations at the catheter tip. Atrial wedges (n=6) were excised from four fresh swine hearts and submerged under pulsatile flow of warm (37oC) phosphate buffered saline. A commercial RFA catheter inserted into a fiber optic sheath allowed for simultaneous measurement of tissue diffuse reflectance (DR) spectra (500-650nm) during application of RF energy. Optical measurements were continuously acquired before, during, and post-ablation, in addition to healthy neighboring tissue. Met-myoglobin, oxy-myoglobin, and deoxy-myoglobin concentrations were extracted from each spectrum using an inverse Monte Carlo method. Tissue injury was validated with Masson's trichrome and hematoxylin and eosin staining. Time courses revealed a rapid increase in tissue Mmb concentrations at the onset of RFA treatment and a gradual plateauing thereafter. Extracted Mmb concentrations were significantly greater post-ablation (p<0.0001) as compared to healthy tissue and correlated well with histological assessment of severe thermal tissue destruction. On going studies are aimed at integrating these findings with prior work on near infrared spectroscopic lesion depth assessment. These results support the use of spectroscopy-facilitated guidance of RFA therapies for real-time permanent injury estimation.

  5. Analytical procedure for mapping the distribution of 10B and 99Tc markers in cryo-sections of animal tissue samples by secondary ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Marchetti, Ilaria; Menichetti, Luca; Kusmic, Claudia; de las Heras, Laura Aldave; Salvadori, Piero; Fuoco, Roger; Belloni, Fabio; L'Abbate, Antonio; Betti, Maria

    2009-09-01

    The development of a complete, standard analytical procedure for a quantitative use of secondary ion mass spectrometry to map the distribution in animal tissues of exogenous isotopes presents difficulties inherently related to sample preparation and preservation, as well as to the specific application being considered. We have tested in two very different cases a procedure based on the cryo-preparation of samples and calibration standards. The applications under investigation were the mapping of 10B in mouse brain tissue, with relevance to the boron neutron capture therapy, and of the perfusion tracer 99Tc in mouse heart tissue, with relevance to the study of microcirculation and cardiovascular pathologies. Scanning electron microscopy and inductively coupled mass spectrometry analysis were used as reference techniques for secondary ion mass spectrometry images and analyte measurements, respectively. Cryo-preparation of tissue sections for ion microscopy proved to be simple and efficient (in terms of structural and chemical integrity) for both brain and heart samples derived from fresh organs. This technique, however, turned out to be reliable only on the brain tissue when applied to the preparation of standards, which required chemical fixation of portions of organs. Brain and heart tissues showed a totally different response to chemical fixation, from both a structural and an analytical point of view. On the one hand, we were able to estimate a relative sensitivity factor for 10B in the cryo-sectioned brain matrix; on the other hand, even without the possibility of an absolute quantification of the 99Tc signal and notwithstanding the presence of an isobaric interference, secondary ion mass spectrometry mapping however proved to be capable to resolve the specific response of the cardiac tissue to the perfusion mechanism.

  6. Telomere Visualization in Tissue Sections using Pyrrole-Imidazole Polyamide Probes.

    PubMed

    Sasaki, Asuka; Ide, Satoru; Kawamoto, Yusuke; Bando, Toshikazu; Murata, Yukinori; Shimura, Mari; Yamada, Kazuhiko; Hirata, Akiyoshi; Nokihara, Kiyoshi; Hirata, Tatsumi; Sugiyama, Hiroshi; Maeshima, Kazuhiro

    2016-01-01

    Pyrrole-Imidazole (PI) polyamides bind to specific DNA sequences in the minor groove with high affinity. Specific DNA labeling by PI polyamides does not require DNA denaturation with harsh treatments of heat and formamide and has the advantages of rapid and less disruptive processing. Previously, we developed tandem hairpin PI polyamide probes (TH59 series), which label telomeres in cultured cell lines more efficiently than conventional methods, such as fluorescence in situ hybridization (FISH). Here, we demonstrate that a TH59 derivative, HPTH59-b, along with immunostaining for specifying cell types in the tissues, visualizes telomeres in mouse and human tissue sections. Quantitative measurements of telomere length with single-cell resolution suggested shorter telomeres in the proliferating cell fractions of tumor than in non-tumor tissues. Thus, PI polyamides are a promising alternative for telomere labeling in clinical research, as well as in cell biology. PMID:27380936

  7. Telomere Visualization in Tissue Sections using Pyrrole–Imidazole Polyamide Probes

    PubMed Central

    Sasaki, Asuka; Ide, Satoru; Kawamoto, Yusuke; Bando, Toshikazu; Murata, Yukinori; Shimura, Mari; Yamada, Kazuhiko; Hirata, Akiyoshi; Nokihara, Kiyoshi; Hirata, Tatsumi; Sugiyama, Hiroshi; Maeshima, Kazuhiro

    2016-01-01

    Pyrrole–Imidazole (PI) polyamides bind to specific DNA sequences in the minor groove with high affinity. Specific DNA labeling by PI polyamides does not require DNA denaturation with harsh treatments of heat and formamide and has the advantages of rapid and less disruptive processing. Previously, we developed tandem hairpin PI polyamide probes (TH59 series), which label telomeres in cultured cell lines more efficiently than conventional methods, such as fluorescence in situ hybridization (FISH). Here, we demonstrate that a TH59 derivative, HPTH59-b, along with immunostaining for specifying cell types in the tissues, visualizes telomeres in mouse and human tissue sections. Quantitative measurements of telomere length with single-cell resolution suggested shorter telomeres in the proliferating cell fractions of tumor than in non-tumor tissues. Thus, PI polyamides are a promising alternative for telomere labeling in clinical research, as well as in cell biology. PMID:27380936

  8. Putative population of adipose-derived stem cells isolated from mediastinal tissue during cardiac surgery.

    PubMed

    Patel, Amit N; Yockman, James; Vargas, Vanessa; Bull, David A

    2013-01-01

    Mesenchymal stem cells have been isolated from various adult human tissues and are valuable for not only therapeutic applications but for the study of tissue homeostasis and disease progression. Subcutaneous adipose depots have been shown to contain large amounts of stem cells. There is little information that has been reported to date describing the isolation and characterization of mesenchymal stem cells from visceral adipose tissue. In this study, we describe a mesenchymal stem cell population isolated from mediastinal adipose depots. The cells express CD44, CD105, CD166, and CD90 and are negative for hematopoietic markers CD34, CD45, and HLA-DR. In addition, the cells have a multilineage potential, with the ability to differentiate into adipogenic, osteogenic, and chondrogenic cell types. The biological function of visceral adipose tissue remains largely unknown and uncharacterized. However, the proximity of adipose tissue to the heart suggests a potential role in the pathogenesis of cardiovascular disease in obesity. In addition, with the ability of fat to regulate metabolic activity in humans, this novel stem cell source may be useful to further study the mechanisms involved in metabolic disorders. PMID:22490339

  9. Quantitative analysis of chromosome in situ hybridization signal in paraffin-embedded tissue sections.

    PubMed

    Dhingra, K; Sneige, N; Pandita, T K; Johnston, D A; Lee, J S; Emami, K; Hortobagyi, G N; Hittelman, W N

    1994-06-01

    Interphase cytogenetic analysis using chromosome-specific probes is increasingly being used to detect chromosomal aberrations on paraffin-embedded tissue sections. However, quantitative analysis of the hybridization signal is confounded by the nuclear slicing that occurs during sectioning. To determine the sensitivity and accuracy of chromosome in situ hybridization for detecting numerical chromosomal aberrations on paraffin-embedded sections, in situ hybridization was performed on sections derived from mixtures of cell populations with known frequencies of numerical chromosomal aberrations and the Chromosome Index (CI) was calculated (i.e., total number of signal spots/number of nuclei counted) as a quantitative measure of chromosome copy number. The presence of 25% or more monosomic or tetrasomic cells in a given population was easily detected as a change in CI (P < 0.05). Lower degrees of polysomy could be detected as a small percentage of nuclear fragments with > 2 signal spots. The CI was not significantly influenced by a change in section thickness from 4 to 8 microM, by an increase in cell size from 478 to 986 microM3, or by the choice of detection method (fluorescence vs. conventional bright-field microscopy). Comparative analysis of touch preparations and tissue sections from the corresponding breast tumors showed that CI accurately reflects the average copy number of chromosomes in intact nuclei and may actually be superior to in situ hybridization on whole nuclei for the detection of numerical chromosomal changes in defined histologic areas. This method is thus a sensitive and accurate means of studying genetic changes in premalignant and malignant tissue, and of assessing the genetic changes associated with specific phenotypes. PMID:7924678

  10. Quantitative digital X-ray imaging using frozen hydrated and frozen dried tissue sections.

    PubMed

    Saubermann, A J; Heyman, R V

    1987-05-01

    Application of quantitative X-ray imaging to frozen hydrated tissue sections has presented a number of major problems including lack of a suitable algorithm which could deal effectively with mass loss due to radiation damage, problems of low characteristic X-ray signal to background ratios, and provide a means of analysis of the same location in both hydrated and dried states. This paper presents details of the application of our algorithm for analysis of frozen hydrated, then dried cryosections applied to quantitative X-ray imaging, which provides relatively high precision quantitative measurement of elemental content (related to both wet and dry weight) and water content of each pixel. This algorithm largely circumvents many of the problems of analysis of frozen hydrated tissue sections. Our algorithm for X-ray imaging obtains reasonably precise quantitative measurements coupled with morphological information by trading speed and image resolution. PMID:3612771

  11. Guide to the identification of fish protozoan and metazoan parasites in stained tissue sections

    USGS Publications Warehouse

    Bruno, D.W.; Nowak, B.; Elliott, D.G.

    2006-01-01

    The identification of protozoan and metazoan parasites is traditionally carried out using a series of classical keys based upon the morphology of the whole organism. However, in stained tissue sections prepared for light microscopy, taxonomic features will be missing, thus making parasite identification difficult. This work highlights the characteristic features of representative parasites in tissue sections to aid identification. The parasite examples discussed are derived from species affecting finfish, and predominantly include parasites associated with disease or those commonly observed as incidental findings in disease diagnostic cases. Emphasis is on protozoan and small metazoan parasites (such as Myxosporidia) because these are the organisms most likely to be missed or mis-diagnosed during gross examination. Figures are presented in colour to assist biologists and veterinarians who are required to assess host/parasite interactions by light microscopy.

  12. Application of color digital holographic microscopy for analysis of stained tissue sections

    NASA Astrophysics Data System (ADS)

    Mo, Xiaoli; Kemper, Björn; Langehanenberg, Patrik; Vollmer, Angelika; Xie, Jinghui; von Bally, Gert

    2009-07-01

    The analysis of stained tissue sections represents an important tool in medical diagnostics. Color digital holographic microscopy offers subsequent multi-focus true color imaging with simultaneous quantitative phase contrast analysis. Investigations on digital recording and numerical reconstructions of color digital holographic images have been performed by applying a transmission microscope experimental setup in holographic off-axis geometry. Three monochromatic digital holograms with different wavelengths in red, green and blue spectral range are recorded. After digital holographic refocusing and compensation for aberrations of the microscope imaging system by digital image correlation the numerically reconstructed amplitude distributions are combined into color images. The applicability of the method is demonstrated by results obtained from stained intestine tissue sections.

  13. [Possibility of the morphometry of the neuronal body and nucleus in cryostat sections of nerve tissue].

    PubMed

    Krasnov, I B

    1982-02-01

    A method of fixation by the Carnoy liquid and of gallocyanine staining is proposed in order to obtain clear-cut boundaries of the neuron body, nucleus and nucleolus in cryostat sections of non-fixed frozen nerve tissue, for subsequent morphometry of the body and nucleus of nerve cells. In the resulting sections, the clearness of boundaries of the body and nucleus in a neuron is sufficient for measuring its diameter with the coefficient of variation not exceeding 2.5%. PMID:7041376

  14. Fully unsupervised inter-individual IR spectral histology of paraffinized tissue sections of normal colon.

    PubMed

    Nguyen, Thi Nguyet Que; Jeannesson, Pierre; Groh, Audrey; Piot, Olivier; Guenot, Dominique; Gobinet, Cyril

    2016-05-01

    In label-free Fourier-transform infrared histology, spectral images are individually recorded from tissue sections, pre-processed and clustered. Each single resulting color-coded image is annotated by a pathologist to obtain the best possible match with tissue structures revealed after Hematoxylin-Eosin staining. However, the main limitations of this approach are the empirical choice of the number of clusters in unsupervised classification, and the marked color heterogeneity between the clustered spectral images. Here, using normal murine and human colon tissues, we developed an automatic multi-image spectral histology to simultaneously analyze a set of spectral images (8 images mice samples and 72 images human ones). This procedure consisted of a joint Extended Multiplicative Signal Correction (EMSC) to numerically deparaffinize the tissue sections, followed by an automated joint K-Means (KM) clustering using the hierarchical double application of Pakhira-Bandyopadhyay-Maulik (PBM) validity index. Using this procedure, the main murine and human colon histological structures were correctly identified at both the intra- and the inter-individual levels, especially the crypts, secreted mucus, lamina propria and submucosa. Here, we show that batched multi-image spectral histology procedure is insensitive to the reference spectrum but highly sensitive to the paraffin model of joint EMSC. In conclusion, combining joint EMSC and joint KM clustering by double PBM application allows to achieve objective and automated batched multi-image spectral histology. PMID:26872124

  15. Disaccharides Protect Antigens from Drying-Induced Damage in Routinely Processed Tissue Sections.

    PubMed

    Boi, Giovanna; Scalia, Carla Rossana; Gendusa, Rossella; Ronchi, Susanna; Cattoretti, Giorgio

    2016-01-01

    Drying of the tissue section, partial or total, during immunostaining negatively affects both the staining of tissue antigens and the ability to remove previously deposited antibody layers, particularly during sequential rounds of de-staining and re-staining for multiple antigens. The cause is a progressive loss of the protein-associated water up to the removal of the non-freezable water, a step which abolishes the immunoavailability of the epitope. In order to describe and prevent these adverse effects, we tested, among other substances, sugars, which are known to protect unicellular organisms from freezing and dehydration, and stabilize drugs and reagents in solid state form in medical devices. Disaccharides (lactose, sucrose) prevented the air drying-induced antigen masking and protected tissue-bound antigens and antibodies from air drying-induced damage. Complete removal of the bound antibody layers by chemical stripping was permitted if lactose was present during air drying. Lactose, sucrose and other disaccharides prevent air drying artifacts, allow homogeneous, consistent staining and the reuse of formalin-fixed, paraffin-embedded tissue sections for repeated immunostaining rounds by guaranteeing constant staining quality in suboptimal hydration conditions. PMID:26487185

  16. Vulnerability to re-entry in simulated two-dimensional cardiac tissue: Effects of electrical restitution and stimulation sequence

    NASA Astrophysics Data System (ADS)

    Tran, Diana X.; Yang, Ming-Jim; Weiss, James N.; Garfinkel, Alan; Qu, Zhilin

    2007-12-01

    Ventricular fibrillation is a lethal arrhythmia characterized by multiple wavelets usually starting from a single or figure-of-eight re-entrant circuit. Understanding the factors regulating vulnerability to the re-entry is essential for developing effective therapeutic strategies to prevent ventricular fibrillation. In this study, we investigated how pre-existing tissue heterogeneities and electrical restitution properties affect the initiation of re-entry by premature extrastimuli in two-dimensional cardiac tissue models. We studied two pacing protocols for inducing re-entry following the "sinus" rhythm (S1) beat: (1) a single premature (S2) extrastimulus in heterogeneous tissue; (2) two premature extrastimuli (S2 and S3) in homogeneous tissue. In the first case, the vulnerable window of re-entry is determined by the spatial dimension and extent of the heterogeneity, and is also affected by electrical restitution properties and the location of the premature stimulus. The vulnerable window first increases as the action potential duration (APD) difference between the inside and outside of the heterogeneous region increases, but then decreases as this difference increases further. Steeper APD restitution reduces the vulnerable window of re-entry. In the second case, electrical restitution plays an essential role. When APD restitution is flat, no re-entry can be induced. When APD restitution is steep, re-entry can be induced by an S3 over a range of S1S2 intervals, which is also affected by conduction velocity restitution. When APD restitution is even steeper, the vulnerable window is reduced due to collision of the spiral tips.

  17. Tissue culture characteristics of maize (Zea mays L.) haploid coleoptile sections.

    PubMed

    Jiang, L; Jing, G X; Li, X Y; Wang, X Q; Xing, Z; Deng, P K; Zhao, R G

    2015-01-01

    Doubled haploid (DH) technology, which is used for rapidly purifying genetic resources, is a key technology in modern maize breeding. The present study evaluated the tissue culture characteristics of maize haploid coleoptile sections, in order to provide a new way of haploid doubling. With 20 combinations of haploid coleoptile sections, obtained by hybridization within Reid, Tangsipingtou, and Term-tropical groups, as explants, we analyzed the induction and differentiation rate of callus, observed the number of root tip chromosomes in regenerated plants, and analyzed the pollen fertility. In addition, we used 47 SSR markers to analyze the genotypes of regenerated plants. The Reid and Tangsipingtou groups had significantly higher induction rates of haploid coleoptile callus compared to the Term-tropical group. Fifteen haploid plants were obtained which had 10 chromosomes in the root tips as assessed by I-KI staining. It was also noticed that the pollen of pollinated anthers were partially fertile. The haploid plants had genetic stability and showed no variation. The Reid and Tangsipingtou groups had good culture characteristics of haploid coleoptile sections, while the Term-tropical group had poor culture characteristics. Genotypes of haploid plants generated by tissue culture were evidenced to come from recombinant types of parents. Thus, this study established a tissue culture system of maize haploid coleoptile. PMID:26662420

  18. Decline in Antigenicity of Tumor Markers by Storage Time Using Pathology Sections Cut From Tissue Microarrays

    PubMed Central

    Ali, Hamid R.; Dawson, Sarah-J.; Le Quesne, John; Provenzano, Elena; Caldas, Carlos; Pharoah, Paul D.P.

    2016-01-01

    Sectioning a whole tissue microarrray (TMA block) and storing the sections maximizes the number of sections obtained, but may impair the antigenicity of the stored sections. We have investigated the impact of TMA section storage on antigenicity. First, we reexamined existing TMA data to determine whether antigenicity in stored sections changes over time. Component scores for each marker, based on cellular compartment of staining and score-type, were evaluated separately. Residual components scores adjusted for grade, tumor size, and node positivity, were regressed on the number of days storage to evaluate the effect of storage time. Storage time ranged from 2 to 1897 days, and the mean change in antigenicity per year ranged from −0.88 (95% confidence interval, −1.11 to −0.65) to 0.035 (95% confidence interval, 0.016-0.054). Further analysis showed no significant improvement in the fit of survival models if storage time adjusted scores were included in the models rather than unadjusted scores. We then compared 3 ways of processing TMA sections after cutting—immediate staining, staining after 1 year, and staining after 1 year coated in wax—on the immunohistochemistry results for: progesterone receptor, a routinely used, robust antibody, and MKI67, which is generally considered less robust. The progesterone receptor scores for stored sections were similar to those for unstored sections, whereas the MKI67 scores for stored sections were substantially different to those for unstored sections. Wax coating made little difference to the results. Biomarker antigenicity shows a small decline over time that is unlikely to have an important effect on studies of prognostic biomarkers. PMID:26067143

  19. Elucidation of transcriptome-wide microRNA binding sites in human cardiac tissues by Ago2 HITS-CLIP

    PubMed Central

    Spengler, Ryan M.; Zhang, Xiaoming; Cheng, Congsheng; McLendon, Jared M.; Skeie, Jessica M.; Johnson, Frances L.; Davidson, Beverly L.; Boudreau, Ryan L.

    2016-01-01

    MicroRNAs (miRs) have emerged as key biological effectors in human health and disease. These small noncoding RNAs are incorporated into Argonaute (Ago) proteins, where they direct post-transcriptional gene silencing via base-pairing with target transcripts. Although miRs have become intriguing biological entities and attractive therapeutic targets, the translational impacts of miR research remain limited by a paucity of empirical miR targeting data, particularly in human primary tissues. Here, to improve our understanding of the diverse roles miRs play in cardiovascular function and disease, we applied high-throughput methods to globally profile miR:target interactions in human heart tissues. We deciphered Ago2:RNA interactions using crosslinking immunoprecipitation coupled with high-throughput sequencing (HITS-CLIP) to generate the first transcriptome-wide map of miR targeting events in human myocardium, detecting 4000 cardiac Ago2 binding sites across >2200 target transcripts. Our initial exploration of this interactome revealed an abundance of miR target sites in gene coding regions, including several sites pointing to new miR-29 functions in regulating cardiomyocyte calcium, growth and metabolism. Also, we uncovered several clinically-relevant interactions involving common genetic variants that alter miR targeting events in cardiomyopathy-associated genes. Overall, these data provide a critical resource for bolstering translational miR research in heart, and likely beyond. PMID:27418678

  20. Gene expression profiling in the fetal cardiac tissue after folate and low dose trichloroethylene exposure

    PubMed Central

    Caldwell, Patricia T.; Manziello, Ann; Howard, Jamie; Palbykin, Brittany; Runyan, Raymond B.; Selmin, Ornella

    2014-01-01

    Background Previous studies show gene expression alterations in rat embryo hearts and cell lines that correspond to the cardio-teratogenic effects of trichloroethylene (TCE) in animal models. One potential mechanism of TCE teratogenicity may be through altered regulation of calcium homeostatic genes with a corresponding inhibition of cardiac function. It has been suggested that TCE may interfere with the folic acid/methylation pathway in liver and kidney and alter gene regulation by epigenetic mechanisms. According to this hypothesis, folate supplementation in the maternal diet should counteract TCE effects on gene expression in the embryonic heart. Approach To identify transcriptional targets altered in the embryonic heart after exposure to TCE, and possible protective effects of folate, we used DNA microarray technology to profile gene expression in embryonic mouse hearts with maternal TCE exposure and dietary changes in maternal folate. Results Exposure to low doses of TCE (10ppb) caused extensive alterations in transcripts encoding proteins involved in transport, ion channel, transcription, differentiation, cytoskeleton, cell cycle and apoptosis. Exogenous folate did not offset the effects of TCE exposure on normal gene expression and both high and low levels of folate produced additional significant changes in gene expression. Conclusions A mechanism where TCE induces a folate deficiency does not explain altered gene expression patterns in the embryonic mouse heart. The data further suggest that use of folate supplementation, in the presence of this toxin, may be detrimental and non-protective of the developing embryo. PMID:19813261

  1. An MRM-based Workflow for Quantifying Cardiac Mitochondrial Protein Phosphorylation in Murine and Human Tissue

    PubMed Central

    Lam, Maggie P.Y.; Scruggs, Sarah B.; Kim, Tae-Young; Zong, Chenggong; Lau, Edward; Wang, Ding; Ryan, Christopher M.; Faull, Kym F.; Ping, Peipei

    2012-01-01

    The regulation of mitochondrial function is essential for cardiomyocyte adaptation to cellular stress. While it has long been understood that phosphorylation regulates flux through metabolic pathways, novel phosphorylation sites are continually being discovered in all functionally distinct areas of the mitochondrial proteome. Extracting biologically meaningful information from these phosphorylation sites requires an adaptable, sensitive, specific and robust method for their quantification. Here we report a multiple reaction monitoring-based mass spectrometric workflow for quantifying site-specific phosphorylation of mitochondrial proteins. Specifically, chromatographic and mass spectrometric conditions for 68 transitions derived from 23 murine and human phosphopeptides, and their corresponding unmodified peptides, were optimized. These methods enabled the quantification of endogenous phosphopeptides from the outer mitochondrial membrane protein VDAC, and the inner membrane proteins ANT and ETC complexes I, III and V. The development of this quantitative workflow is a pivotal step for advancing our knowledge and understanding of the regulatory effects of mitochondrial protein phosphorylation in cardiac physiology and pathophysiology. PMID:22387130

  2. Robust image-based estimation of cardiac tissue parameters and their uncertainty from noisy data.

    PubMed

    Neumann, Dominik; Mansi, Tommaso; Georgescu, Bogdan; Kamen, Ali; Kayvanpour, Elham; Amr, Ali; Sedaghat-Hamedani, Farbod; Haas, Jan; Katus, Hugo; Meder, Benjamin; Hornegger, Joachim; Comaniciu, Dorin

    2014-01-01

    Clinical applications of computational cardiac models require precise personalization, i.e. fitting model parameters to capture patient's physiology. However, due to parameter non-identifiability, limited data, uncertainty in the clinical measurements, and modeling assumptions, various combinations of parameter values may exist that yield the same quality of fit. Hence, there is a need for quantifying the uncertainty in estimated parameters and to ascertain the uniqueness of the found solution. This paper presents a stochastic method to estimate the parameters of an image-based electromechanical model of the heart and their uncertainty due to noise in measurements. First, Bayesian inference is applied to fully estimate the posterior probability density function (PDF) of the model. To that end, Markov Chain Monte Carlo sampling is used, which is made computationally tractable by employing a fast surrogate model based on Polynomial Chaos Expansion, instead of the true forward model. Then, we use the mean-shift algorithm to automatically find the modes of the PDF and select the most likely one while being robust to noise. The approach is used to estimate global active stress and passive stiffness from invasive pressure and image-based volume quantification. Experiments on eight patients showed that not only our approach yielded goodness of fits equivalent to a well-established deterministic method, but we could also demonstrate the non-uniqueness of the problem and report uncertainty estimates, crucial information for subsequent clinical assessments of the personalized models. PMID:25485357

  3. Automated cardiac sarcomere analysis from second harmonic generation images

    NASA Astrophysics Data System (ADS)

    Garcia-Canadilla, Patricia; Gonzalez-Tendero, Anna; Iruretagoyena, Igor; Crispi, Fatima; Torre, Iratxe; Amat-Roldan, Ivan; Bijnens, Bart H.; Gratacos, Eduard

    2014-05-01

    Automatic quantification of cardiac muscle properties in tissue sections might provide important information related to different types of diseases. Second harmonic generation (SHG) imaging provides a stain-free microscopy approach to image cardiac fibers that, combined with our methodology of the automated measurement of the ultrastructure of muscle fibers, computes a reliable set of quantitative image features (sarcomere length, A-band length, thick-thin interaction length, and fiber orientation). We evaluated the performance of our methodology in computer-generated muscle fibers modeling some artifacts that are present during the image acquisition. Then, we also evaluated it by comparing it to manual measurements in SHG images from cardiac tissue of fetal and adult rabbits. The results showed a good performance of our methodology at high signal-to-noise ratio of 20 dB. We conclude that our automated measurements enable reliable characterization of cardiac fiber tissues to systematically study cardiac tissue in a wide range of conditions.

  4. Data on CUX1 isoforms in idiopathic pulmonary fibrosis lung and systemic sclerosis skin tissue sections.

    PubMed

    Ikeda, Tetsurou; Fragiadaki, Maria; Shi-Wen, Xu; Ponticos, Markella; Khan, Korsa; Denton, Christopher; Garcia, Patricia; Bou-Gharios, George; Yamakawa, Akio; Morimoto, Chikao; Abraham, David

    2016-09-01

    This data article contains complementary figures related to the research article entitled, "Transforming growth factor-β-induced CUX1 isoforms are associated with fibrosis in systemic sclerosis lung fibroblasts" (Ikeda et al. (2016) [2], http://dx.doi.org/10.1016/j.bbrep.2016.06.022), which presents that TGF-β increased CUX1 binding in the proximal promoter and enhancer of the COL1A2 and regulated COL1. Further, in the scleroderma (SSc) lung and diffuse alveolar damage lung sections, CUX1 localized within the α- smooth muscle actin (α-SMA) positive cells (Fragiadaki et al., 2011) [1], "High doses of TGF-beta potently suppress type I collagen via the transcription factor CUX1" (Ikeda et al., 2016) [2]. Here we show that CUX1 isoforms are localized within α-smooth muscle actin-positive cells in SSc skin and idiopathic pulmonary fibrosis (IPF) lung tissue sections. In particular, at the granular and prickle cell layers in the SSc skin sections, CUX1 and α-SMA are co-localized. In addition, at the fibrotic loci in the IPF lung tissue sections, CUX1 localized within the α-smooth muscle actin (α-SMA) positive cells. PMID:27583344

  5. Poly(Glycerol Sebacate)/Poly(Butylene Succinate-Butylene Dilinoleate) Fibrous Scaffolds for Cardiac Tissue Engineering

    PubMed Central

    Tallawi, Marwa; Zebrowski, David C.; Rai, Ranjana; Roether, Judith A.; Schubert, Dirk W.; El Fray, Miroslawa; Aifantis, Katerina E.

    2015-01-01

    The present article investigates the use of a novel electrospun fibrous blend of poly(glycerol sebacate) (PGS) and poly(butylene succinate-butylene dilinoleate) (PBS-DLA) as a candidate for cardiac tissue engineering. Random electrospun fibers with various PGS/PBS-DLA compositions (70/30, 60/40, 50/50, and 0/100) were fabricated. To examine the suitability of these fiber blends for heart patches, their morphology, as well as their physical, chemical, and mechanical properties were measured before examining their biocompatibility through cell adhesion. The fabricated fibers were bead-free and exhibited a relatively narrow diameter distribution. The addition of PBS-DLA to PGS resulted in an increase of the average fiber diameter, whereas increasing the amount of PBS-DLA decreased the hydrophilicity and the water uptake of the nanofibrous scaffolds to values that approached those of neat PBS-DLA nanofibers. Moreover, the addition of PBS-DLA significantly increased the elastic modulus. Initial toxicity studies with C2C12 myoblast cells up to 72 h confirmed nontoxic behavior of the blends. Immunofluorescence analyses and scanning electron microscopy analyses confirmed that C2C12 cells showed better cell attachment and proliferation on electrospun mats with higher PBS-DLA content. However, immunofluorescence analyses of the 3-day-old rat cardiomyocytes cultured for 2 and 5 days demonstrated better attachment on the 70/30 fibers containing well-aligned sarcomeres and expressing high amounts of connexin 43 in cellular junctions indicating efficient cell-to-cell communication. It can be concluded, therefore, that fibrous PGS/PBS-DLA scaffolds exhibit promising characteristics as a biomaterial for cardiac patch applications. PMID:25439964

  6. Poly(glycerol sebacate)/poly(butylene succinate-butylene dilinoleate) fibrous scaffolds for cardiac tissue engineering.

    PubMed

    Tallawi, Marwa; Zebrowski, David C; Rai, Ranjana; Roether, Judith A; Schubert, Dirk W; El Fray, Miroslawa; Engel, Felix B; Aifantis, Katerina E; Boccaccini, Aldo R

    2015-06-01

    The present article investigates the use of a novel electrospun fibrous blend of poly(glycerol sebacate) (PGS) and poly(butylene succinate-butylene dilinoleate) (PBS-DLA) as a candidate for cardiac tissue engineering. Random electrospun fibers with various PGS/PBS-DLA compositions (70/30, 60/40, 50/50, and 0/100) were fabricated. To examine the suitability of these fiber blends for heart patches, their morphology, as well as their physical, chemical, and mechanical properties were measured before examining their biocompatibility through cell adhesion. The fabricated fibers were bead-free and exhibited a relatively narrow diameter distribution. The addition of PBS-DLA to PGS resulted in an increase of the average fiber diameter, whereas increasing the amount of PBS-DLA decreased the hydrophilicity and the water uptake of the nanofibrous scaffolds to values that approached those of neat PBS-DLA nanofibers. Moreover, the addition of PBS-DLA significantly increased the elastic modulus. Initial toxicity studies with C2C12 myoblast cells up to 72 h confirmed nontoxic behavior of the blends. Immunofluorescence analyses and scanning electron microscopy analyses confirmed that C2C12 cells showed better cell attachment and proliferation on electrospun mats with higher PBS-DLA content. However, immunofluorescence analyses of the 3-day-old rat cardiomyocytes cultured for 2 and 5 days demonstrated better attachment on the 70/30 fibers containing well-aligned sarcomeres and expressing high amounts of connexin 43 in cellular junctions indicating efficient cell-to-cell communication. It can be concluded, therefore, that fibrous PGS/PBS-DLA scaffolds exhibit promising characteristics as a biomaterial for cardiac patch applications. PMID:25439964

  7. Plasma tissue inhibitor of matrix metalloproteinase-1 (TIMP-1): an independent predictor of poor response to cardiac resynchronization therapy

    PubMed Central

    Tolosana, Jose María; Mont, Lluís; Sitges, Marta; Berruezo, Antonio; Delgado, Victoria; Vidal, Bàrbara; Tamborero, David; Morales, Manel; Batlle, Montserrat; Roig, Eulalia; Castel, M. Angeles; Pérez-Villa, Félix; Godoy, Miguel; Brugada, Josep

    2010-01-01

    Aims Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play a role in left ventricular structural remodelling. The aim of our study was to analyse MMP-2 and TIMP-1 levels as predictors of poor response to cardiac resynchronization therapy (CRT). Methods and results A cohort of 42 CRT patients from our centre was prospectively evaluated at baseline and after 12-month follow-up. MMP-2 and TIMP-1 assays were performed prior to CRT implant. Cardiac resynchronization therapy responders were defined as patients who survived, were not transplanted, and increased their basal 6 min walking distance test (6MWDT) by ≥10% or improved their NYHA functional class. Overall, 25 patients (60%) were classed as responders. At 12-month follow-up, six patients (14.2%) had died and one (2.4%) patient had been transplanted. Compared with responders, non-responders had higher levels of TIMP-1 (277 ± 59 vs. 216 ± 46 ng/mL, P = 0.001), MMP-2 (325 ± 115 vs. 258 ± 56 ng/mL, P = 0.02), and creatinine (1.76 ± 0.8 vs. 1.25 ± 0.3 mg/dL, P = 0.01). In a multivariate analysis, TIMP-1 was the only independent predictor of non-response to CRT [OR 0.97, 95% (CI 0.96–0.99) P = 0.005]. TIMP-1≥248 ng/mL predicted non-response with 71% sensitivity and 72% specificity. Conclusion TIMP-1 is an independent predictor of non-response in patients treated with CRT. PMID:20360066

  8. Stereoselective binding in cardiac tissue of the enatiomers of benzetimide, and antimuscarinic drug.

    PubMed Central

    Gray, J A; Lüllmann, H; Mitchelson, F; Reil, G H

    1976-01-01

    1 Benzetimide, possessing two stable enantiomers, dexetimide and levetimide, has been investigated in guinea-pig atria with respect to its atropine-like action and its tissue distribution. 2 The antagonistic potency of dexetimide was found to be over 6000 times higher than that of levetimide, the pA2 values being 9.82 and 6.0 respectively. 3 The tissue accumulation was investigated for both isomers in the concentration range from 1.5 X 10(-9) M to 10(-6) M yielding tissue to medium ratios (T/M) of between approximately 50 and 10. The highest values were found for the lowest concentrations. At any concentration investigated, dexetimide exhibited a higher uptake than the levoisomer. 4 The rate of uptake and washout of dexetimide was extremely slow, that of levetimide being considerably faster at equimolar concentrations. The same pattern held true for the onset and decline of the antagonistic action. 5 The high accumulation was found to be almost entirely due to unspecific binding. Even in the case of dexetimide the relative size of the receptor compartment could not be determined. The unspecific binding sites displayed a certain stereoselectivity but to a much lesser extent than the specific receptor binding sites. PMID:1260229

  9. Insulin-like growth factor-I and slow, bi-directional perfusion enhance the formation of tissue-engineered cardiac grafts.

    PubMed

    Cheng, Mingyu; Moretti, Matteo; Engelmayr, George C; Freed, Lisa E

    2009-03-01

    Biochemical and mechanical signals enabling cardiac regeneration can be elucidated using in vitro tissue-engineering models. We hypothesized that insulin-like growth factor-I (IGF) and slow, bi-directional perfusion could act independently and interactively to enhance the survival, differentiation, and contractile performance of tissue-engineered cardiac grafts. Heart cells were cultured on three-dimensional porous scaffolds in medium with or without supplemental IGF and in the presence or absence of slow, bi-directional perfusion that enhanced transport and provided shear stress. Structural, molecular, and electrophysiologic properties of the resulting grafts were quantified on culture day 8. IGF had independent, beneficial effects on apoptosis (p < 0.01), cellular viability (p < 0.01), contractile amplitude (p < 0.01), and excitation threshold (p < 0.01). Perfusion independently affected the four aforementioned parameters and also increased amounts of cardiac troponin-I (p < 0.01), connexin-43 (p < 0.05), and total protein (p < 0.01) in the grafts. Interactive effects of IGF and perfusion on apoptosis were also present (p < 0.01). Myofibrillogenesis and spontaneous contractility were present only in grafts cultured with perfusion, although contractility was inducible by electrical field stimulation of grafts from all groups. Our findings demonstrate that multi-factorial stimulation of tissue-engineered cardiac grafts using IGF and perfusion resulted in independent and interactive effects on heart cell survival, differentiation, and contractility. PMID:18759675

  10. Fluorescence in situ hybridization for the identification of Treponema pallidum in tissue sections.

    PubMed

    Petrich, Annett; Rojas, Pablo; Schulze, Julia; Loddenkemper, Christoph; Giacani, Lorenzo; Schneider, Thomas; Hertel, Moritz; Kikhney, Judith; Moter, Annette

    2015-10-01

    Syphilis is often called the great imitator because of its frequent atypical clinical manifestations that make the disease difficult to recognize. Because Treponema pallidum subsp. pallidum, the infectious agent of syphilis, is yet uncultivated in vitro, diagnosis is usually made using serology; however, in cases where serology is inconclusive or in patients with immunosuppression where these tests may be difficult to interpret, the availability of a molecular tool for direct diagnosis may be of pivotal importance. Here we present a fluorescence in situ hybridization (FISH) assay that simultaneously identifies and analyzes spatial distribution of T. pallidum in histological tissue sections. For this assay the species-specific FISH probe TPALL targeting the 16S rRNA of T. pallidum was designed in silico and evaluated using T. pallidum infected rabbit testicular tissue and a panel of non-syphilis spirochetes as positive and negative controls, respectively, before application to samples from four syphilis-patients. In a HIV positive patient, FISH showed the presence of T. pallidum in inguinal lymph node tissue. In a patient not suspected to suffer from syphilis but underwent surgery for phimosis, numerous T. pallidum cells were found in preputial tissue. In two cases with oral involvement, FISH was able to differentiate T. pallidum from oral treponemes and showed infection of the oral mucosa and tonsils, respectively. The TPALL FISH probe is now readily available for in situ identification of T. pallidum in selected clinical samples as well as T. pallidum research applications and animal models. PMID:26365167

  11. Nonlinear behaviour of conduction and block in cardiac tissue with heterogeneous expression of connexin 43.

    PubMed

    Prudat, Yann; Kucera, Jan P

    2014-11-01

    Altered gap junctional coupling potentiates slow conduction and arrhythmias. To better understand how heterogeneous connexin expression affects conduction at the cellular scale, we investigated conduction in tissue consisting of two cardiomyocyte populations expressing different connexin levels. Conduction was mapped using microelectrode arrays in cultured strands of foetal murine ventricular myocytes with predefined contents of connexin 43 knockout (Cx43KO) cells. Corresponding computer simulations were run in randomly generated two-dimensional tissues mimicking the cellular architecture of the strands. In the cultures, the relationship between conduction velocity (CV) and Cx43KO cell content was nonlinear. CV first decreased significantly when Cx43KO content was increased from 0 to 50%. When the Cx43KO content was ≥60%, CV became comparable to that in 100% Cx43KO strands. Co-culturing Cx43KO and wild-type cells also resulted in significantly more heterogeneous conduction patterns and in frequent conduction blocks. The simulations replicated this behaviour of conduction. For Cx43KO contents of 10-50%, conduction was slowed due to wavefront meandering between Cx43KO cells. For Cx43KO contents ≥60%, clusters of remaining wild-type cells acted as electrical loads that impaired conduction. For Cx43KO contents of 40-60%, conduction exhibited fractal characteristics, was prone to block, and was more sensitive to changes in ion currents compared to homogeneous tissue. In conclusion, conduction velocity and stability behave in a nonlinear manner when cardiomyocytes expressing different connexin amounts are combined. This behaviour results from heterogeneous current-to-load relationships at the cellular level. Such behaviour is likely to be arrhythmogenic in various clinical contexts in which gap junctional coupling is heterogeneous. PMID:25128085

  12. Liquid microjunction surface sampling of acetaminophen, terfenadine and their metabolites in thin tissue sections

    SciTech Connect

    Kertesz, Vilmos; Paranthaman, Nithya; Moench, Paul; Catoire, Alexandre; Flarakos, Jimmy; Van Berkel, Gary J.

    2014-10-01

    The aim of this paper was to evaluate the analytical performance of a fully automated droplet-based surface-sampling system for determining the distribution of the drugs acetaminophen and terfenadine, and their metabolites, in rat thin tissue sections. The following are the results: The rank order of acetaminophen concentration observed in tissues was stomach > small intestine > liver, while the concentrations of its glucuronide and sulfate metabolites were greatest in the liver and small intestine. Terfenadine was most concentrated in the liver and kidney, while its major metabolite, fexofenadine, was found in the liver and small intestine. In conclusion, the spatial distributions of both drugs and their respective metabolites observed in this work were consistent with previous studies using radiolabeled drugs.

  13. Liquid microjunction surface sampling of acetaminophen, terfenadine and their metabolites in thin tissue sections

    DOE PAGESBeta

    Kertesz, Vilmos; Paranthaman, Nithya; Moench, Paul; Catoire, Alexandre; Flarakos, Jimmy; Van Berkel, Gary J.

    2014-10-01

    The aim of this paper was to evaluate the analytical performance of a fully automated droplet-based surface-sampling system for determining the distribution of the drugs acetaminophen and terfenadine, and their metabolites, in rat thin tissue sections. The following are the results: The rank order of acetaminophen concentration observed in tissues was stomach > small intestine > liver, while the concentrations of its glucuronide and sulfate metabolites were greatest in the liver and small intestine. Terfenadine was most concentrated in the liver and kidney, while its major metabolite, fexofenadine, was found in the liver and small intestine. In conclusion, the spatialmore » distributions of both drugs and their respective metabolites observed in this work were consistent with previous studies using radiolabeled drugs.« less

  14. Pulmonary tissue volume, cardiac output, and diffusing capacity in sustained microgravity.

    PubMed

    Verbanck, S; Larsson, H; Linnarsson, D; Prisk, G K; West, J B; Paiva, M

    1997-09-01

    In microgravity (microG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to microG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls (P < 0.001). There was a concomittant reduction in stroke volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P < 0.05) late in flight. These findings suggest that, despite increased pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to microG. PMID:9292467

  15. Pulmonary tissue volume, cardiac output, and diffusing capacity in sustained microgravity

    NASA Technical Reports Server (NTRS)

    Verbanck, S.; Larsson, H.; Linnarsson, D.; Prisk, G. K.; West, J. B.; Paiva, M.

    1997-01-01

    In microgravity (microG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to microG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls (P < 0.001). There was a concomittant reduction in stroke volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P < 0.05) late in flight. These findings suggest that, despite increased pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to microG.

  16. Combined in situ Hybridization/Immunohistochemistry (ISH/IH) on Free-floating Vibratome Tissue Sections

    PubMed Central

    Lopez, Manuel E.

    2016-01-01

    In situ hybridization and immunostaining are common techniques for localizing gene expression, the mRNA and protein respectively, within tissues. Both techniques can be applied to tissue sections to achieve similar goals, but in some cases, it is necessary to use them together. For example, complement C1q is a secreted protein complex that can target the innate immune response during inflammation. Complement has been found to be elevated early and before severe neurodegeneration in several disease models. Thus, complement may serve as an important marker for disease progression and may contribute to the pathology under certain conditions. Since complement is a secreted complex, immunostaining for C1q does not necessarily reveal where compliment is produced. In situ hybridization for complement components, C1q a, b, or c mRNA, is ideal to mark complement producing cells in tissue. In situ hybridization can be coupled with cell-type-specific immunostaining for accurate identification of the cell types involved. Protein localization and mRNA localization together can reveal details as to the relationship between complement producing and complement target cells within disease tissues. Here we outline the steps for combined in situ hybridization and immunostaining on the same tissue section. The protocol outlined here has been designed for detection of complement C1q in neurons and microglia in the mouse brain. Provided here are two approaches for combined ISH/IH. In the 1st example, in situ hybridization of C1q mRNA is performed together with fluorescent detection of Purkinje neuron cell bodies using Calbindin-D28K antibody. In the 2nd example, C1q mRNA in situ is performed together with 3,3’-diaminobenzidine (DAB) detection of microglia using CD68 antibody. Please note that modifications to the protocol may be needed for the use of distinct probes and antibodies, as well as alternate tissue-processing methods that are not specified herein. For appropriate examples

  17. Acoustic-radiation-force-induced shear wave propagation in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Bouchard, Richard R.; Wolf, Patrick D.; Hsu, Stephen J.; Dumont, Douglas M.; Trahey, Gregg E.

    2009-02-01

    Shear wave elasticity imaging (SWEI) was employed to track acoustic radiation force (ARF)-induced shear waves in the myocardium of a beating heart. Shear waves were generated in and tracked through the myocardium of the left ventricular free wall (LVFW) in an in vivo heart that was exposed through a thoracotomy; matched studies were also preformed on an ex vivo myocardial specimen. Average shear wave velocities ranged from 2.22 to 2.53 m/s for the ex vivo specimen and 1.5 to 2.9 m/s (1.5-2.09 m/s during diastole; 2.9 m/s during systole) for in vivo specimens. Despite the known rotation of myocardial fiber orientation with tissue depth, there was no statistically significant shear wave velocity depth dependence observed in any of the experimental trials.

  18. The Role of anisotropy on the initiation and propagation of action currents in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Baudenbacher, F.; Peters, N. T.; Koola, J.; Holzer, J. R.; Fong, L. E.; Trontelj, Z.; Wikswo, J. P.

    2001-03-01

    A central question in biomagnetism is whether the biomagnetic field can contain information not present in the bioelectric potential. We have examined the physiological basis of magnetically-detectable but electrically silent sources, and identified the roles of tissue anisotropy and the spiral architecture of the heart: electrically silent current loops can in principle flow perpendicular to the direction of propagation. We have conducted experiments using an ultra high resolution scanning SQUID microscope in combination with epi-fluorescence imaging system to measure the action currents and the transmembrane potentials of a propagating wavefront in a Langendorff perfused rabbit heart. An activation wavefront has been induced on either the leftventricular free wall or the appex. Results show characteristic differences in the propagation velocities as a function of angle, which provide strong evidence for electrically silent sources.

  19. Cardiomyocytes In Vitro Adhesion Is Actively Influenced by Biomimetic Synthetic Peptides for Cardiac Tissue Engineering

    PubMed Central

    Huerta-Cantillo, Rocio; Comisso, Marina; Danesin, Roberta; Ghezzo, Francesca; Naso, Filippo; Gastaldello, Alessandra; Schittullo, Eleonora; Buratto, Edward; Spina, Michele; Gerosa, Gino; Dettin, Monica

    2012-01-01

    Scaffolds for tissue engineering must be designed to direct desired events such as cell attachment, growth, and differentiation. The incorporation of extracellular matrix-derived peptides into biomaterials has been proposed to mimic biochemical signals. In this study, three synthetic fragments of fibronectin, vitronectin, and stromal-derived factor-1 were investigated for the first time as potential adhesive sequences for cardiomyocytes (CMs) compared to smooth muscle cells. CMs are responsive to all peptides to differing degrees, demonstrating the existence of diverse adhesion mechanisms. The pretreatment of nontissue culture well surfaces with the (Arginine-Glycine-Aspartic Acid) RGD sequence anticipated the appearance of CMs' contractility compared to the control (fibronectin-coated well) and doubled the length of cell viability. Future prospects are the inclusion of these sequences into biomaterial formulation with the improvement in cell adhesion that could play an important role in cell retention during dynamic cell seeding. PMID:22011064

  20. How to measure propagation velocity in cardiac tissue: a simulation study

    PubMed Central

    Linnenbank, Andre C.; de Bakker, Jacques M. T.; Coronel, Ruben

    2014-01-01

    To estimate conduction velocities from activation times in myocardial tissue, the “average vector” method computes all the local activation directions and velocities from local activation times and estimates the fastest and slowest propagation speed from these local values. The “single vector” method uses areas of apparent uniform elliptical spread of activation and chooses a single vector for the estimated longitudinal velocity and one for the transversal. A simulation study was performed to estimate the influence of grid size, anisotropy, and vector angle bin size. The results indicate that the “average vector” method can best be used if the grid- or bin-size is large, although systematic errors occur. The “single vector” method performs better, but requires human intervention for the definition of fiber direction. The average vector method can be automated. PMID:25101004

  1. Carpal Tunnel Cross-Sectional Area Affected by Soft Tissues Abutting the Carpal Bones.

    PubMed

    Gabra, Joseph N; Li, Zong-Ming

    2013-02-01

    The carpal tunnel accommodates free movement of its contents, and the tunnel's cross-sectional area is a useful morphological parameter for the evaluation of the space available for the carpal tunnel contents and of potential nerve compression in the tunnel. The osseous boundary of the carpal bones as the dorsal border of the carpal tunnel is commonly used to determine the tunnel area, but this boundary contains soft tissues such as numerous intercarpal ligaments and the flexor carpi radialis tendon. The aims of this study were to quantify the thickness of the soft tissues abutting the carpal bones and to investigate how this soft tissue influences the calculation of the carpal tunnel area. Magnetic resonance images were analyzed for eight cadaveric specimens. A medical balloon with a physiological pressure was inserted into an evacuated tunnel to identify the carpal tunnel boundary. The balloon-based (i.e. true carpal tunnel) and osseous-based carpal tunnel boundaries were extracted and divided into regions corresponding to the hamate, capitate, trapezoid, trapezium, and transverse carpal ligament (TCL). From the two boundaries, the overall and regional soft tissue thicknesses and areas were calculated. The soft tissue thickness was significantly greater for the trapezoid (3.1±1.2mm) and trapezium (3.4±1.0mm) regions than for the hamate (0.7±0.3mm) and capitate (1.2±0.5mm) regions. The carpal tunnel area using the osseous boundary (243.0±40.4mm(2)) was significantly larger than the balloon-based area (183.9±29.7mm(2)) with a ratio of 1.32. In other words, the carpal tunnel area can be estimated as 76% (= 1/1.32) of the osseous-based area. The abundance of soft tissue in the trapezoid and trapezium regions can be attributed mainly to the capitate-trapezium ligament and the flexor carpi radialis tendon. Inclusion of such soft tissue leads to overestimations of the carpal tunnel area. Correct quantification of the carpal tunnel area aids in examining carpal

  2. Carpal Tunnel Cross-Sectional Area Affected by Soft Tissues Abutting the Carpal Bones

    PubMed Central

    Gabra, Joseph N.; Li, Zong-Ming

    2013-01-01

    The carpal tunnel accommodates free movement of its contents, and the tunnel's cross-sectional area is a useful morphological parameter for the evaluation of the space available for the carpal tunnel contents and of potential nerve compression in the tunnel. The osseous boundary of the carpal bones at the dorsal border of the carpal tunnel is commonly used to determine the tunnel area, but this boundary contains soft tissues such as numerous intercarpal ligaments and the flexor carpi radialis tendon. The aims of this study were to quantify the thickness of the soft tissues abutting the carpal bones and to investigate how this soft tissue influences the calculation of the carpal tunnel area. Magnetic resonance images were analyzed for eight cadaveric specimens. A medical balloon with a physiological pressure was inserted into an evacuated tunnel to identify the carpal tunnel boundary. The balloon-based (i.e., true carpal tunnel) and osseous-based carpal tunnel boundaries were extracted and divided into regions corresponding to the hamate, capitate, trapezoid, trapezium, and transverse carpal ligament (TCL). From the two boundaries, the overall and regional soft tissue thicknesses and areas were calculated. The soft tissue thickness was significantly greater for the trapezoid (3.1 ± 1.2 mm) and trapezium (3.4 ± 1.0 mm) regions than for the hamate (0.7 ± 0.3 mm) and capitate (1.2 ± 0.5 mm) regions. The carpal tunnel area using the osseous boundary (243.0 ± 40.4 mm2) was significantly larger than the balloon-based area (183.9 ± 29.7 mm2) with a ratio of 1.32. In other words, the carpal tunnel area can be estimated as 76% (= 1/1.32) of the osseous-based area. The abundance of soft tissue in the trapezoid and trapezium regions can be attributed mainly to the capitotrapezial ligament and the flexor carpi radialis tendon. Inclusion of such soft tissue leads to overestimations of the carpal tunnel area. Correct quantification of the carpal

  3. A Framework for 3D Vessel Analysis using Whole Slide Images of Liver Tissue Sections

    PubMed Central

    Liang, Yanhui; Wang, Fusheng; Treanor, Darren; Magee, Derek; Roberts, Nick; Teodoro, George; Zhu, Yangyang; Kong, Jun

    2015-01-01

    Three-dimensional (3D) high resolution microscopic images have high potential for improving the understanding of both normal and disease processes where structural changes or spatial relationship of disease features are significant. In this paper, we develop a complete framework applicable to 3D pathology analytical imaging, with an application to whole slide images of sequential liver slices for 3D vessel structure analysis. The analysis workflow consists of image registration, segmentation, vessel cross-section association, interpolation, and volumetric rendering. To identify biologically-meaningful correspondence across adjacent slides, we formulate a similarity function for four association cases. The optimal solution is then obtained by constrained Integer Programming. We quantitatively and qualitatively compare our vessel reconstruction results with human annotations. Validation results indicate a satisfactory concordance as measured both by region-based and distance-based metrics. These results demonstrate a promising 3D vessel analysis framework for whole slide images of liver tissue sections. PMID:27034719

  4. Family-based associations in measures of psychological distress and quality of life in a cardiac screening clinic for inheritable cardiac diseases: a cross-sectional study

    PubMed Central

    2013-01-01

    Background Family-based cardiac screening programmes for persons at risk for genetic cardiac diseases are now recommended. However, the psychological wellbeing and health related quality of life (QoL) of such screened patients is poorly understood, especially in younger patients. We sought to examine wellbeing and QoL in a representative group of adults aged 16 and over in a dedicated family cardiac screening clinic. Methods Prospective survey of consecutive consenting patients attending a cardiac screening clinic, over a 12 month period. Data were collected using two health measurement tools: the Short Form 12 (version 2) and the Hospital Anxiety and Depression Scale (HADS), along with baseline demographic and screening visit-related data. The HADS and SF-12v.2 outcomes were compared by age group. Associations with a higher HADS score were examined using logistic regression, with multi-level modelling used to account for the family-based structure of the data. Results There was a study response rate of 86.6%, with n=334 patients providing valid HADS data (valid response rate 79.5%), and data on n=316 retained for analysis. One-fifth of patients were aged under 25 (n=61). Younger patients were less likely than older to describe significant depression on their HADS scale (p<0.0001), although there were overall no difference between the prevalence of a significant HADS score between the younger and older age groups (18.0% vs 20.0%, p=0.73). Significant positive associates of a higher HADS score were having lower educational attainment, being single or separated, and being closely related to the family proband. Between-family variance in anxiety and depression scores was greater than within-family variance. Conclusions High levels of anxiety were seen amongst patients attending a family-based cardiac screening clinic.Younger patients also had high rates of clinically significant anxiety. Higher levels of anxiety and depression tends to run in families, and this has

  5. Preparation of a porous conductive scaffold from aniline pentamer-modified polyurethane/PCL blend for cardiac tissue engineering.

    PubMed

    Baheiraei, Nafiseh; Yeganeh, Hamid; Ai, Jafar; Gharibi, Reza; Ebrahimi-Barough, Somayeh; Azami, Mahmoud; Vahdat, Sadaf; Baharvand, Hossein

    2015-10-01

    A novel biodegradable electroactive polyurethane containing aniline pentamer (AP) was blended with polycaprolactone (PCL). The prepared blend (PB) and PCL were further fabricated in to scaffolds using a mixture of poly(ethylene glycol) and salt particles in a double porogen particulate leaching and compression molding methodology. Scaffolds held open and interconnected pores having pore size ranging from several μm to 150 µm. PB scaffolds had compression modulus and strength of 4.1 and 1.3 MPa, respectively. The conductivity of the scaffold was measured as 10(-5) ± 0.09 S .cm(-1) and preserved for at least 100 h post fabrication. Scaffolds supported neonatal cardiomyocytes adhesion and growth with PB showing more extensive effect on the expression of the cardiac genes involved in muscle contraction and relaxation (troponin-T) and cytoskeleton alignment (actinin-4). Our results highlight the potential of incorporation of AP as an electroactive moiety for induction of cardiomyocyte proliferation and repair of damaged heart tissue. PMID:25765879

  6. MALDI Mass Spectrometric Imaging of Cardiac Tissue Following Myocardial Infarction in a Rat Coronary Artery Ligation Model

    PubMed Central

    Menger, Robert F.; Stutts, Whitney L.; Anbukumar, Dhanam S.; Bowden, John A.; Ford, David A.; Yost, Richard A.

    2011-01-01

    Although acute myocardial infarction (MI) is consistently among the top causes of death in the United States, the spatial distribution of lipids and metabolites following MI remains to be elucidated. This work presents the investigation of an in vivo rat model of MI using mass spectrometric imaging (MSI) and multivariate data analysis. MSI was conducted on cardiac tissue following a 24-hour left anterior descending coronary artery ligation in order to analyze multiple compound classes. First, the spatial distribution of a small metabolite, creatine, was used to identify areas of infarcted myocardium. Second, multivariate data analysis and tandem mass spectrometry were used to identify phospholipid (PL) markers of MI. A number of lysophospholipids demonstrated increased ion signal in areas of infarction. In contrast, select intact PLs demonstrated decreased ion signal in the area of infarction. The complementary nature of these two lipid classes suggest increased activity of phospholipase A2, an enzyme that has been implicated in coronary heart disease and inflammation. PMID:22141424

  7. Quantifying the effect of tissue deformation on diffusion-weighted MRI: a mathematical model and an efficient simulation framework applied to cardiac diffusion imaging.

    PubMed

    Mekkaoui, Imen; Moulin, Kevin; Croisille, Pierre; Pousin, Jerome; Viallon, Magalie

    2016-08-01

    Cardiac motion presents a major challenge in diffusion weighted MRI, often leading to large signal losses that necessitate repeated measurements. The diffusion process in the myocardium is difficult to investigate because of the unqualified sensitivity of diffusion measurements to cardiac motion. A rigorous mathematical formalism is introduced to quantify the effect of tissue motion in diffusion imaging. The presented mathematical model, based on the Bloch-Torrey equations, takes into account deformations according to the laws of continuum mechanics. Approximating this mathematical model by using finite elements method, numerical simulations can predict the sensitivity of the diffusion signal to cardiac motion. Different diffusion encoding schemes are considered and the diffusion weighted MR signals, computed numerically, are compared to available results in literature. Our numerical model can identify the existence of two time points in the cardiac cycle, at which the diffusion is unaffected by myocardial strain and cardiac motion. Of course, these time points depend on the type of diffusion encoding scheme. Our numerical results also show that the motion sensitivity of the diffusion sequence can be reduced by using either spin echo technique with acceleration motion compensation diffusion gradients or stimulated echo acquisition mode with unipolar and bipolar diffusion gradients. PMID:27385441

  8. Quantifying the effect of tissue deformation on diffusion-weighted MRI: a mathematical model and an efficient simulation framework applied to cardiac diffusion imaging

    NASA Astrophysics Data System (ADS)

    Mekkaoui, Imen; Moulin, Kevin; Croisille, Pierre; Pousin, Jerome; Viallon, Magalie

    2016-08-01

    Cardiac motion presents a major challenge in diffusion weighted MRI, often leading to large signal losses that necessitate repeated measurements. The diffusion process in the myocardium is difficult to investigate because of the unqualified sensitivity of diffusion measurements to cardiac motion. A rigorous mathematical formalism is introduced to quantify the effect of tissue motion in diffusion imaging. The presented mathematical model, based on the Bloch–Torrey equations, takes into account deformations according to the laws of continuum mechanics. Approximating this mathematical model by using finite elements method, numerical simulations can predict the sensitivity of the diffusion signal to cardiac motion. Different diffusion encoding schemes are considered and the diffusion weighted MR signals, computed numerically, are compared to available results in literature. Our numerical model can identify the existence of two time points in the cardiac cycle, at which the diffusion is unaffected by myocardial strain and cardiac motion. Of course, these time points depend on the type of diffusion encoding scheme. Our numerical results also show that the motion sensitivity of the diffusion sequence can be reduced by using either spin echo technique with acceleration motion compensation diffusion gradients or stimulated echo acquisition mode with unipolar and bipolar diffusion gradients.

  9. Preclinical Evaluation of the Immunomodulatory Properties of Cardiac Adipose Tissue Progenitor Cells Using Umbilical Cord Blood Mesenchymal Stem Cells: A Direct Comparative Study

    PubMed Central

    Perea-Gil, Isaac; Monguió-Tortajada, Marta; Gálvez-Montón, Carolina; Bayes-Genis, Antoni; Borràs, Francesc E.; Roura, Santiago

    2015-01-01

    Cell-based strategies to regenerate injured myocardial tissue have emerged over the past decade, but the optimum cell type is still under scrutiny. In this context, human adult epicardial fat surrounding the heart has been characterized as a reservoir of mesenchymal-like progenitor cells (cardiac ATDPCs) with potential clinical benefits. However, additional data on the possibility that these cells could trigger a deleterious immune response following implantation are needed. Thus, in the presented study, we took advantage of the well-established low immunogenicity of umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) to comparatively assess the immunomodulatory properties of cardiac ATDPCs in an in vitro allostimulatory assay using allogeneic mature monocyte-derived dendritic cells (MDDCs). Similar to UCBMSCs, increasing amounts of seeded cardiac ATDPCs suppressed the alloproliferation of T cells in a dose-dependent manner. Secretion of proinflammatory cytokines (IL6, TNFα, and IFNγ) was also specifically modulated by the different numbers of cardiac ATDPCs cocultured. In summary, we show that cardiac ATDPCs abrogate T cell alloproliferation upon stimulation with allogeneic mature MDDCs, suggesting that they could further regulate a possible harmful immune response in vivo. Additionally, UCBMSCs can be considered as valuable tools to preclinically predict the immunogenicity of prospective regenerative cells. PMID:25861626

  10. Counting particles in tissue sections: choices of methods and importance of calibration to minimize biases.

    PubMed

    von Bartheld, C

    2002-04-01

    Investigators must choose between counting methods to quantify microscopic particles in tissues. The conventional profile-based ("model-based" or "2D-") counting methods have been criticized for their potential biases due to assumptions about shapes, sizes, and orientation of particles when converting profile counts into cell numbers. New stereological methods ("design-based" or "3D-") methods such as the optical disector or physical disector were initially introduced as being inherently unbiased. Recent calibration analyses and comparisons of results from different investigators have revealed the potential for significant biases in the most efficient and most frequently used design-based method, the optical disector. This review aims to objectively assess the strengths and limitations of current profile- and disector-based cell counting methods by examination of studies in which these methods have been calibrated against the "gold-standard", counts obtained by 3-dimensional reconstruction of serial sections. Advantages and disadvantages of each counting method and the associated embedding and sectioning techniques are compared and frequent mistakes and pitfalls of each technique are discussed. The importance of a calibration step for each technique is emphasized, and a protocol is provided for a quick and simple calibration by a "sampling" 3-D reconstruction of limited serial sections. Trends in the usage of counting methods are analyzed in four major journals. It is hoped that this review will be helpful, for both investigators and manuscript reviewers, in clarifying some of the contentious issues in the choice and implementation of appropriate methods for particle counting in tissue sections. PMID:11962763

  11. Liquid Microjunction Surface Sampling Probe Electrospray Mass Spectrometry for Detection of Drugs and Metabolites in Thin Tissue Sections

    SciTech Connect

    Van Berkel, Gary J; Kertesz, Vilmos; Koeplinger, Kenneth A.; Vavek, Marissa; Kong, Ah-Ng Tony

    2008-01-01

    A self-aspirating, liquid micro-junction surface sampling probe/electrospray emitter mass spectrometry system was demonstrated for use in the direct analysis of spotted and dosed drugs and their metabolites in thin tissue sections. Proof-of-principle sampling and analysis directly from tissue without the need for sample preparation was demonstrated first by raster scanning a region on a section of rat liver onto which reserpine was spotted. The mass spectral signal from selected reaction monitoring was used to develop a chemical image of the spotted drug on the tissue. The probe was also used to selectively spot sample areas of sagittal whole mouse body tissue sections that had been dosed orally (90 mg/kg) with R,S-sulforaphane 3 hrs prior to sacrifice. Sulforaphane and its glutathione and N-acetyl cysteine conjugates were monitored with selected reaction monitoring and detected in the stomach and various other tissues from the dosed mouse. No signal for these species was observed in the tissue from a control mouse. The same dosed tissue section was used to illustrate the possibility of obtaining a line scan across the whole body section. In total these results illustrate the potential for rapid screening of the distribution of drugs and metabolites in tissue sections with the micro-liquid junction surface sampling probe/electrospray mass spectrometry approach.

  12. Magnetic and Fluorescent Imaging of Wave Front Propagation in Cardiac Tissue

    NASA Astrophysics Data System (ADS)

    Holzer, Jenny R.; Chancellor, Eric; Sidorov, Veniamin; Fong, Luis; Baudenbacher, Franz

    2002-03-01

    To investigate the origin of the magnetocardiogram (MCG), we mapped excitation wave fronts on the left ventricle of a Langendorff perfused isolated rabbit heart using high-resolution LTS-SQUID microscopy and epi-fluorescent imaging with sub-millimeter resolution. The combination of the two methods allows us to map the transmembrane potential and the magnetic field over the same area of the left ventricle. The leading edge of the action potential can be defined as the wave front and identified in the magnetic data as a border between areas of opposite polarity. Calculating the current from the magnetic field shows a strong component parallel to the wave front. Therefore, the MCG on the surface of the heart is mainly generated by a propagating three-dimensional sheet of current. The shape and the size of the MCG depend strongly on the direction of the currents relative to the fiber orientation. These observations are in qualitative agreement with predictions using a two-dimensional bidomain model by Roth et al (1999). However, due to imhomogenities in the tissue properties, the wave front propagates at different angles relative to the fiber orientation and can only be identified as planar over small localized areas of, typically, a few millimeters. This explains the variations in the MCG over the scan area and confirms the sensitivity of the MCG to the angle between current flow and fiber orientation.

  13. Quantitative assessment of brain tissue oxygenation in porcine models of cardiac arrest and cardiopulmonary resuscitation using hyperspectral near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Lotfabadi, Shahin S.; Toronov, Vladislav; Ramadeen, Andrew; Hu, Xudong; Kim, Siwook; Dorian, Paul; Hare, Gregory M. T.

    2014-03-01

    Near-infrared spectroscopy (NIRS) is a non-invasive tool to measure real-time tissue oxygenation in the brain. In an invasive animal experiment we were able to directly compare non-invasive NIRS measurements on the skull with invasive measurements directly on the brain dura matter. We used a broad-band, continuous-wave hyper-spectral approach to measure tissue oxygenation in the brain of pigs under the conditions of cardiac arrest, cardiopulmonary resuscitation (CPR), and defibrillation. An additional purpose of this research was to find a correlation between mortality due to cardiac arrest and inadequacy of the tissue perfusion during attempts at resuscitation. Using this technique we measured the changes in concentrations of oxy-hemoglobin [HbO2] and deoxy-hemoglobin [HHb] to quantify the tissue oxygenation in the brain. We also extracted cytochrome c oxidase changes Δ[Cyt-Ox] under the same conditions to determine increase or decrease in cerebral oxygen delivery. In this paper we proved that applying CPR, [HbO2] concentration and tissue oxygenation in the brain increase while [HHb] concentration decreases which was not possible using other measurement techniques. We also discovered a similar trend in changes of both [Cyt-Ox] concentration and tissue oxygen saturation (StO2). Both invasive and non-invasive measurements showed similar results.

  14. A compact and versatile microfluidic probe for local processing of tissue sections and biological specimens

    NASA Astrophysics Data System (ADS)

    Cors, J. F.; Lovchik, R. D.; Delamarche, E.; Kaigala, G. V.

    2014-03-01

    The microfluidic probe (MFP) is a non-contact, scanning microfluidic technology for local (bio)chemical processing of surfaces based on hydrodynamically confining nanoliter volumes of liquids over tens of micrometers. We present here a compact MFP (cMFP) that can be used on a standard inverted microscope and assist in the local processing of tissue sections and biological specimens. The cMFP has a footprint of 175 × 100 × 140 mm3 and can scan an area of 45 × 45 mm2 on a surface with an accuracy of ±15 μm. The cMFP is compatible with standard surfaces used in life science laboratories such as microscope slides and Petri dishes. For ease of use, we developed self-aligned mounted MFP heads with standardized "chip-to-world" and "chip-to-platform" interfaces. Switching the processing liquid in the flow confinement is performed within 90 s using a selector valve with a dead-volume of approximately 5 μl. We further implemented height-compensation that allows a cMFP head to follow non-planar surfaces common in tissue and cellular ensembles. This was shown by patterning different macroscopic copper-coated topographies with height differences up to 750 μm. To illustrate the applicability to tissue processing, 5 μm thick M000921 BRAF V600E+ melanoma cell blocks were stained with hematoxylin to create contours, lines, spots, gradients of the chemicals, and multiple spots over larger areas. The local staining was performed in an interactive manner using a joystick and a scripting module. The compactness, user-friendliness, and functionality of the cMFP will enable it to be adapted as a standard tool in research, development and diagnostic laboratories, particularly for the interaction with tissues and cells.

  15. Epidemiological and Survival Trends of Pediatric Cardiac Arrests in Emergency Departments in Korea: A Cross-sectional, Nationwide Report.

    PubMed

    Ahn, Jae Yun; Lee, Mi Jin; Kim, Hyun; Yoon, Han Deok; Jang, Hye Young

    2015-09-01

    Cardiac arrest (CA) in children is associated with high mortality rates. In Korea, cohort studies regarding the outcomes of pediatric CAs are lacking, especially in emergency departments (EDs) or in-hospital settings. This study was conducted to examine the trends in epidemiology and survival outcomes in children with resuscitation-attempted CAs using data from a cross-sectional, national, ED-based clinical registry. We extracted cases in which cardiopulmonary resuscitation and/or manual defibrillation were performed according to treatment codes using the National Emergency Department Information System (NEDIS) from 2008 to 2012. The total number of ED visits registered in the NEDIS during the 5-yr evaluation period was 20,424,530; among these, there were 2,970 resuscitation-attempted CAs in children. The annual rates of pediatric CAs per 1,000 ED visits showed an upward trend from 2.81 in 2009 to 3.62 in 2012 (P for trend = 0.045). The median number of estimated pediatric CAs at each ED was 7.8 (25th to 75th percentile, 4 to 13) per year. The overall rates for admission survival and discharge survival were 35.2% and 12.8%, respectively. The survival outcome of adults increased substantially over the past 5 yr (11.8% in 2008, 11.7% in 2010, and 13.6% in 2012; P for trend = 0.001); however, the results for children did not improve (13.6% in 2008, 11.4% in 2010, and 13.7% in 2012; P for trend = 0.870). Conclusively, we found that the overall incidence of pediatric CAs in EDs increased substantially over the past 5 yr, but without significantly higher survival outcomes. PMID:26339179

  16. High Resolution Systematic Digital Histological Quantification of Cardiac Fibrosis and Adipose Tissue in Phospholamban p.Arg14del Mutation Associated Cardiomyopathy

    PubMed Central

    Gho, Johannes M. I. H.; van Es, René; Stathonikos, Nikolas; Harakalova, Magdalena; te Rijdt, Wouter P.; Suurmeijer, Albert J. H.; van der Heijden, Jeroen F.; de Jonge, Nicolaas; Chamuleau, Steven A. J.; de Weger, Roel A.; Asselbergs, Folkert W.; Vink, Aryan

    2014-01-01

    Myocardial fibrosis can lead to heart failure and act as a substrate for cardiac arrhythmias. In dilated cardiomyopathy diffuse interstitial reactive fibrosis can be observed, whereas arrhythmogenic cardiomyopathy is characterized by fibrofatty replacement in predominantly the right ventricle. The p.Arg14del mutation in the phospholamban (PLN) gene has been associated with dilated cardiomyopathy and recently also with arrhythmogenic cardiomyopathy. Aim of the present study is to determine the exact pattern of fibrosis and fatty replacement in PLN p.Arg14del mutation positive patients, with a novel method for high resolution systematic digital histological quantification of fibrosis and fatty tissue in cardiac tissue. Transversal mid-ventricular slices (n = 8) from whole hearts were collected from patients with the PLN p.Arg14del mutation (age 48±16 years; 4 (50%) male). An in-house developed open source MATLAB script was used for digital analysis of Masson's trichrome stained slides (http://sourceforge.net/projects/fibroquant/). Slides were divided into trabecular, inner and outer compact myocardium. Per region the percentage of connective tissue, cardiomyocytes and fatty tissue was quantified. In PLN p.Arg14del mutation associated cardiomyopathy, myocardial fibrosis is predominantly present in the left posterolateral wall and to a lesser extent in the right ventricular wall, whereas fatty changes are more pronounced in the right ventricular wall. No difference in distribution pattern of fibrosis and adipocytes was observed between patients with a clinical predominantly dilated and arrhythmogenic cardiomyopathy phenotype. In the future, this novel method for quantifying fibrosis and fatty tissue can be used to assess cardiac fibrosis and fatty tissue in animal models and a broad range of human cardiomyopathies. PMID:24732829

  17. Feature-based analysis of mouse prostatic intraepithelial neoplasia in histological tissue sections

    PubMed Central

    Ruusuvuori, Pekka; Valkonen, Mira; Nykter, Matti; Visakorpi, Tapio; Latonen, Leena

    2016-01-01

    This paper describes work presented at the Nordic Symposium on Digital Pathology 2015, in Linköping, Sweden. Prostatic intraepithelial neoplasia (PIN) represents premalignant tissue involving epithelial growth confined in the lumen of prostatic acini. In the attempts to understand oncogenesis in the human prostate, early neoplastic changes can be modeled in the mouse with genetic manipulation of certain tumor suppressor genes or oncogenes. As with many early pathological changes, the PIN lesions in the mouse prostate are macroscopically small, but microscopically spanning areas often larger than single high magnification focus fields in microscopy. This poses a challenge to utilize full potential of the data acquired in histological specimens. We use whole prostates fixed in molecular fixative PAXgene™, embedded in paraffin, sectioned through and stained with H&E. To visualize and analyze the microscopic information spanning whole mouse PIN (mPIN) lesions, we utilize automated whole slide scanning and stacked sections through the tissue. The region of interests is masked, and the masked areas are processed using a cascade of automated image analysis steps. The images are normalized in color space, after which exclusion of secretion areas and feature extraction is performed. Machine learning is utilized to build a model of early PIN lesions for determining the probability for histological changes based on the calculated features. We performed a feature-based analysis to mPIN lesions. First, a quantitative representation of over 100 features was built, including several features representing pathological changes in PIN, especially describing the spatial growth pattern of lesions in the prostate tissue. Furthermore, we built a classification model, which is able to align PIN lesions corresponding to grading by visual inspection to more advanced and mild lesions. The classifier allowed both determining the probability of early histological changes for uncategorized

  18. Feature-based analysis of mouse prostatic intraepithelial neoplasia in histological tissue sections.

    PubMed

    Ruusuvuori, Pekka; Valkonen, Mira; Nykter, Matti; Visakorpi, Tapio; Latonen, Leena

    2016-01-01

    This paper describes work presented at the Nordic Symposium on Digital Pathology 2015, in Linköping, Sweden. Prostatic intraepithelial neoplasia (PIN) represents premalignant tissue involving epithelial growth confined in the lumen of prostatic acini. In the attempts to understand oncogenesis in the human prostate, early neoplastic changes can be modeled in the mouse with genetic manipulation of certain tumor suppressor genes or oncogenes. As with many early pathological changes, the PIN lesions in the mouse prostate are macroscopically small, but microscopically spanning areas often larger than single high magnification focus fields in microscopy. This poses a challenge to utilize full potential of the data acquired in histological specimens. We use whole prostates fixed in molecular fixative PAXgene™, embedded in paraffin, sectioned through and stained with H&E. To visualize and analyze the microscopic information spanning whole mouse PIN (mPIN) lesions, we utilize automated whole slide scanning and stacked sections through the tissue. The region of interests is masked, and the masked areas are processed using a cascade of automated image analysis steps. The images are normalized in color space, after which exclusion of secretion areas and feature extraction is performed. Machine learning is utilized to build a model of early PIN lesions for determining the probability for histological changes based on the calculated features. We performed a feature-based analysis to mPIN lesions. First, a quantitative representation of over 100 features was built, including several features representing pathological changes in PIN, especially describing the spatial growth pattern of lesions in the prostate tissue. Furthermore, we built a classification model, which is able to align PIN lesions corresponding to grading by visual inspection to more advanced and mild lesions. The classifier allowed both determining the probability of early histological changes for uncategorized

  19. Affinity imaging mass spectrometry (AIMS): high-throughput screening for specific small molecule interactions with frozen tissue sections.

    PubMed

    Yoshimi, T; Kawabata, S; Taira, S; Okuno, A; Mikawa, R; Murayama, S; Tanaka, K; Takikawa, O

    2015-11-01

    A novel screening system, using affinity imaging mass spectrometry (AIMS), has been developed to identify protein aggregates or organ structures in unfixed human tissue. Frozen tissue sections are positioned on small (millimetre-scale) stainless steel chips and incubated with an extensive library of small molecules. Candidate molecules showing specific affinity for the tissue section are identified by imaging mass spectrometry (IMS). As an example application, we screened over a thousand compounds against Alzheimer's disease (AD) brain tissue and identified several compounds with high affinity for AD brain sections containing tau deposits compared to age-matched controls. It should also be possible to use AIMS to isolate chemical compounds with affinity for tissue structures or components that have been extensively modified by events such as oxidation, phosphorylation, acetylation, aggregation, racemization or truncation, for example, due to aging. It may also be applicable to biomarker screening programs. PMID:26365298

  20. Silica Encapsulated Gold Nanoparticles as SERS Labels for the Detection of Lymphoma B-Cells in Tissue Sections

    NASA Astrophysics Data System (ADS)

    Al-Faouri, Tamara

    The surface of silica encapsulated gold nanoparticles with trans-1,2-bis (4-pyridyl) ethylene Raman active dye were utilized as SERS labels to target CD20 surface protein on lymphoma B-cells in human tissue sections with CLL or FL. SERS labels were functionalized with various antibody linkers including carboxylic, aldehyde, and heterobifunctional PEG chains with an NHS end, to permit them to bind to tissue section samples. NP samples and tissue sections were characterized through UV-Vis spectroscopy, TEM, XPS, Zeta potential measurements, Dark Field microscopy, Raman spectroscopy, NMR, and AFM. The number of SERS labels present on a tissue sample was estimated using dark field images and a particle counting software. It was found that the heterobifunctional PEG chains linker provided the most specific binding of SERS labels with an estimated NP count of 1.33x106 NPs on the whole tissue and produced the highest Raman scatter intensity of approximately 48600 counts.

  1. Grinding and polishing instead of sectioning for the tissue samples with a graft: Implications for light and electron microscopy.

    PubMed

    Mukhamadiyarov, Rinat A; Sevostyanova, Victoria V; Shishkova, Daria K; Nokhrin, Andrey V; Sidorova, Olga D; Kutikhin, Anton G

    2016-06-01

    A broad use of the graft replacement requires a detailed investigation of the host-graft interaction, including both histological examination and electron microscopy. A high quality sectioning of the host tissue with a graft seems to be complicated; in addition, it is difficult to examine the same tissue area by both of the mentioned microscopy techniques. To solve these problems, we developed a new technique of epoxy resin embedding with the further grinding, polishing, and staining. Graft-containing tissues prepared by grinding and polishing preserved their structure; however, sectioning frequently required the explantation of the graft and led to tissue disintegration. Moreover, stained samples prepared by grinding and polishing may then be assessed by both light microscopy and backscattered scanning electron microscopy. Therefore, grinding and polishing outperform sectioning when applied to the tissues with a graft. PMID:27023831

  2. 2-Oxoglutarate dehydrogenase is a more significant source of O2(·-)/H2O2 than pyruvate dehydrogenase in cardiac and liver tissue.

    PubMed

    Mailloux, Ryan J; Gardiner, Danielle; O'Brien, Marisa

    2016-08-01

    Pyruvate dehydrogenase (Pdh) and 2-oxoglutarate dehydrogenase (Ogdh) are vital for Krebs cycle metabolism and sources of reactive oxygen species (ROS). O2(·-)/H2O2 formation by Pdh and Ogdh from porcine heart were compared when operating under forward or reverse electron transfer conditions. Comparisons were also conducted with liver and cardiac mitochondria. During reverse electron transfer (RET) from NADH, purified Ogdh generated ~3-3.5× more O2(·-)/H2O2 in comparison to Pdh when metabolizing 0.5-10µM NADH. Under forward electron transfer (FET) conditions Ogdh generated ~2-4× more O2(·-)/H2O2 than Pdh. In both liver and cardiac mitochondria, Ogdh displayed significantly higher rates of ROS formation when compared to Pdh. Ogdh was also a significant source of ROS in liver mitochondria metabolizing 50µM and 500µM pyruvate or succinate. Finally, we also observed that DTT directly stimulated O2(·-)/H2O2 formation by purified Pdh and Ogdh and in cardiac or liver mitochondria in the absence of substrates and cofactors. Taken together, Ogdh is a more potent source of ROS than Pdh in liver and cardiac tissue. Ogdh is also an important ROS generator regardless of whether pyruvate or succinate serve as the sole source of carbon. Our observations provide insight into the ROS generating capacity of either complex in cardiac and liver tissue. The evidence presented herein also indicates DTT, a reductant that is routinely added to biological samples, should be avoided when assessing mitochondrial O2(·-)/H2O2 production. PMID:27394173

  3. Thick-section fluorescence in situ hybridization on formalin-fixed, paraffin-embedded archival tissue provides a histogenetic profile.

    PubMed Central

    Thompson, C. T.; LeBoit, P. E.; Nederlof, P. M.; Gray, J. W.

    1994-01-01

    Fluorescence in situ hybridization has become a major tool for analysis of gene and chromosome copy number in normal and malignant tissue. The technique has been applied widely to fresh tissue and dispersed formalin-fixed, paraffin-embedded archival tissue, but its use on sections of archival tissue has largely been limited to sections < 6 mu thick. This does not provide intact, uncut nuclei for accurate analysis of gene or chromosome copy number. We report here a method of hybridization to sections > 20 microns thick that overcomes these difficulties. Key developments were the use of DNA probes directly labeled with fluorochromes and optical sectioning using laser-scanning confocal microscopy. Images Figure 2 Figure 3 PMID:8311111

  4. Detecting Distance between Injected Microspheres and Target Tumor via 3D Reconstruction of Tissue Sections

    SciTech Connect

    Carson, James P.; Kuprat, Andrew P.; Colby, Sean M.; Davis, Cassi A.; Basciano, Christopher; Greene, Kevin; Feo, John T.; Kennedy, Andrew

    2012-08-28

    One treatment increasing in use for solid tumors in the liver is radioembolization via the delivery of 90Y microspheres to the vascular bed within or near the location of the tumor. It is desirable as part of the treatment for the microspheres to embed preferentially in or near the tumor. This work details an approach for analyzing the deposition of microspheres with respect to the location of the tumor. The approach used is based upon thin-slice serial sectioning of the tissue sample, followed by high resolution imaging, microsphere detection, and 3-D reconstruction of the tumor surface. Distance from the microspheres to the tumor was calculated using a fast deterministic point inclusion method.

  5. Molecular differential cross sections for low angle photon scattering in tissues

    NASA Astrophysics Data System (ADS)

    Tartari, Agostino

    1999-08-01

    Measurements of molecular cross sections of coherently scattered photons were obtained by means of powder diffraction data analysis in the interval χ=0-6.4 nm -1 ( χ=sin( θ/2)/ λ; where θ is the scattering angle and λ the incident wavelength in units of nm). Accurate correction procedures were applied to the raw diffraction data. Data for fat and PMMA (polymethyl methacrylate)—reported in a previous analysis (Tartari A, Casnati E, Bonifazzi C, Baraldi C, 1997b. Phys. Med. Biol. 42, 2551-2560.—were found to agree quite well when compared to the results obtained with different quality of beams and analysis techniques. Investigation on bony tissue is presented for the first time, and a simple model has been carried out in order to segment the mineral and non-mineral components. Finally, a basic set of curves for the linear differential scattering coefficient is proposed in order to simulate photons scattering by tissue in terms of linear combination of such curves.

  6. Visualizing Oxazine 4 nerve-specific fluorescence ex vivo in frozen tissue sections

    NASA Astrophysics Data System (ADS)

    Barth, Connor W.; Gibbs, Summer L.

    2016-03-01

    Nerve damage plagues surgical outcomes and remains a major burden for patients, surgeons, and the healthcare system. Fluorescence image-guided surgery using nerve specific small molecule fluorophores offers a solution to diminish surgical nerve damage through improved intraoperative nerve identification and visualization. Oxazine 4 has shown superior nerve specificity in initial testing in vivo, while exhibiting a red shifted excitation and emission spectra compared to other nerve-specific fluorophores. However, Oxazine 4 does not exhibit near-infrared (NIR) excitation and emission, which would be ideal to improve penetration depth and nerve signal to background ratios for in vivo imaging. Successful development of a NIR nerve-specific fluorophore will require understanding of the molecular target of fluorophore nerve specificity. While previous small molecule nerve-specific fluorophores have demonstrated excellent ex vivo nerve specificity, Oxazine 4 ex vivo nerve specific fluorescence has been difficult to visualize. In the present study, we examined each step of the ex vivo fluorescence microscopy sample preparation procedure to discover how in vivo nerve-specific fluorescence is changed during ex vivo tissue sample preparation. Through step-by-step examination we found that Oxazine 4 fluorescence was significantly diminished by washing and mounting tissue sections for microscopy. A method to preserve Oxazine 4 nerve specific fluorescence ex vivo was determined, which can be utilized for visualization by fluorescence microscopy.

  7. Solute Transport in Cyclically Deformed Porous Tissue Scaffolds with Controlled Pore Cross-Sectional Geometries

    PubMed Central

    Op Den Buijs, Jorn; Lu, Lichun; Jorgensen, Steven M.; Dragomir-Daescu, Dan; Yaszemski, Michael J.

    2009-01-01

    The objective of this study was to investigate the influence of pore geometry on the transport rate and depth after repetitive mechanical deformation of porous scaffolds for tissue engineering applications. Flexible cubic imaging phantoms with pores in the shape of a circular cylinder, elliptic cylinder, and spheroid were fabricated from a biodegradable polymer blend using a combined 3D printing and injection molding technique. The specimens were immersed in fluid and loaded with a solution of a radiopaque solute. The solute distribution was quantified by recording 20 μm pixel-resolution images in an X-ray microimaging scanner at selected time points after intervals of dynamic straining with a mean strain of 8.6 ± 1.6% at 1.0 Hz. The results show that application of cyclic strain significantly increases the rate and depth of solute transport, as compared to diffusive transport alone, for all pore shapes. In addition, pore shape, pore size, and the orientation of the pore cross-sectional asymmetry with respect to the direction of strain greatly influence solute transport. Thus, pore geometry can be tailored to increase transport rates and depths in cyclically deformed scaffolds, which is of utmost importance when thick, metabolically functional tissues are to be engineered. PMID:19196145

  8. Hyperspectral microscopic analysis of normal, benign and carcinoma microarray tissue sections

    NASA Astrophysics Data System (ADS)

    Maggioni, Mauro; Davis, Gustave L.; Warner, Frederick J.; Geshwind, Frank B.; Coppi, Andreas C.; DeVerse, Richard A.; Coifman, Ronald R.

    2006-02-01

    We apply a unique micro-optoelectromechanical tuned light source and new algorithms to the hyper-spectral microscopic analysis of human colon biopsies. The tuned light prototype (Plain Sight Systems Inc.) transmits any combination of light frequencies, range 440nm 700nm, trans-illuminating H and E stained tissue sections of normal (N), benign adenoma (B) and malignant carcinoma (M) colon biopsies, through a Nikon Biophot microscope. Hyper-spectral photomicrographs, randomly collected 400X magnication, are obtained with a CCD camera (Sensovation) from 59 different patient biopsies (20 N, 19 B, 20 M) mounted as a microarray on a single glass slide. The spectra of each pixel are normalized and analyzed to discriminate among tissue features: gland nuclei, gland cytoplasm and lamina propria/lumens. Spectral features permit the automatic extraction of 3298 nuclei with classification as N, B or M. When nuclei are extracted from each of the 59 biopsies the average classification among N, B and M nuclei is 97.1%; classification of the biopsies, based on the average nuclei classification, is 100%. However, when the nuclei are extracted from a subset of biopsies, and the prediction is made on nuclei in the remaining biopsies, there is a marked decrement in performance to 60% across the 3 classes. Similarly the biopsy classification drops to 54%. In spite of these classification differences, which we believe are due to instrument and biopsy normalization issues, hyper-spectral analysis has the potential to achieve diagnostic efficiency needed for objective microscopic diagnosis.

  9. RF-based two-dimensional cardiac strain estimation: a validation study in a tissue-mimicking phantom.

    PubMed

    Langeland, Stian; D'hooge, Jan; Claessens, Tom; Claus, Piet; Verdonck, Pascal; Suetens, Paul; Sutherland, George R; Bijnens, Bart

    2004-11-01

    Strain and strain rate imaging have been shown to be useful techniques for the assessment of cardiac function. However, one of the major problems of these techniques is their angle dependency. In order to overcome this problem, a new method for estimating the strain (rate) tensor had previously been proposed by our lab. The aim of this study was to validate this methodology in a phantom setup. A tubular thick-walled tissue-mimicking phantom was fixed in a water tank. Varying the intraluminal pressure resulted in a cyclic radial deformation. The 2D strain was calculated from the 2D velocity estimates, obtained from 2D radio frequency (RF) tracking using a 1D kernel. Additionally, ultrasonic microcrystals were implanted on the outer and inner walls of the tube in order to give an independent measurement of the instantaneous wall thickness. The two methods were compared by means of linear regression, the correlation coefficient, and Bland-Altman statistics. As expected, the strain estimates dominated by the azimuth velocity component were less accurate than the ones dominated by the axial velocity component. Correlation coefficients were found to be r = 0.78 for the former estimates and r = 0.83 was found for the latter. Given that the overall shape and timing of the 2D deformation were very accurate (r = 0.95 and r = 0.84), these results were within acceptable limits for clinical applications. The 2D RF-tracking using a 1D kernel thus allows for 2D, and therefore angle-independent, strain estimation. PMID:15600099

  10. Mechanical and electrophysiological studies on the positive inotropic effect of 2-phenyl-4-oxo-hydroquinoline in rat cardiac tissues.

    PubMed Central

    Su, M. J.; Chang, G. J.; Kuo, S. C.

    1993-01-01

    1. The pharmacological and electrophysiological effect of 2-phenyl-4-oxo-hydroquinoline (YT-1), a new synthetic agent, were determined in rat isolated cardiac tissues and ventricular myocytes. 2. YT-1 was found to have a positive inotropic effect in both atria and ventricular muscles but did not cause significant increases in the spontaneously beating rate of right atria. 3. The positive inotropic effect of YT-1 was antagonized neither by beta-nor by alpha-adrenoceptor antagonists but was partially antagonized by a Ca2+ channel blocker (verapamil) and a K+ channel blocker (4-AP). 4. The action potential duration and amplitude of ventricular cells were progressively increased as the concentration of YT-1 was increased from 3 to 30 microM. 5. A voltage clamp study revealed that the prolongation of action potential duration by YT-1 was associated with a prominent inhibition of 4-AP-sensitive transient outward current (I(to)). At potentials negative to the reversal potential of K1-channels, the inward current through these channels was partially reduced by YT-1. At potentials positive to the reversal potential, the outward current through these channels was affected very little. 6. Although YT-1 blocked the amplitude of I(to), the voltage-dependence of the steady-state inactivation of I(to), was unaffected. 7. Apart from the inhibition of K+ currents, YT-1 also inhibited the sodium inward current. 8. The evidence suggests that YT-1 increases the slow inward Ca2+ current (ICa) significantly. 9. It is concluded that the positive inotropic effect of YT-1 is due predominantly to the increase of ICa and inhibition of I(to).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8106106

  11. Insulin-like Growth Factor-I and Slow, Bi-directional Perfusion Enhance the Formation of Tissue-Engineered Cardiac Grafts

    PubMed Central

    Cheng, Mingyu; Moretti, Matteo; Engelmayr, George C.

    2009-01-01

    Biochemical and mechanical signals enabling cardiac regeneration can be elucidated using in vitro tissue-engineering models. We hypothesized that insulin-like growth factor-I (IGF) and slow, bi-directional perfusion could act independently and interactively to enhance the survival, differentiation, and contractile performance of tissue-engineered cardiac grafts. Heart cells were cultured on three-dimensional porous scaffolds in medium with or without supplemental IGF and in the presence or absence of slow, bi-directional perfusion that enhanced transport and provided shear stress. Structural, molecular, and electrophysiologic properties of the resulting grafts were quantified on culture day 8. IGF had independent, beneficial effects on apoptosis (p < 0.01), cellular viability (p < 0.01), contractile amplitude (p < 0.01), and excitation threshold (p < 0.01). Perfusion independently affected the four aforementioned parameters and also increased amounts of cardiac troponin-I (p < 0.01), connexin-43 (p < 0.05), and total protein (p < 0.01) in the grafts. Interactive effects of IGF and perfusion on apoptosis were also present (p < 0.01). Myofibrillogenesis and spontaneous contractility were present only in grafts cultured with perfusion, although contractility was inducible by electrical field stimulation of grafts from all groups. Our findings demonstrate that multi-factorial stimulation of tissue-engineered cardiac grafts using IGF and perfusion resulted in independent and interactive effects on heart cell survival, differentiation, and contractility. PMID:18759675

  12. Postmortem mRNA Expression Patterns in Left Ventricular Myocardial Tissues and Their Implications for Forensic Diagnosis of Sudden Cardiac Death

    PubMed Central

    Son, Gi Hoon; Park, Seong Hwan; Kim, Yunmi; Kim, Ji Yeon; Kim, Jin Wook; Chung, Sooyoung; Kim, Yu-Hoon; Kim, Hyun; Hwang, Juck-Joon; Seo, Joong-Seok

    2014-01-01

    Sudden cardiac death (SCD), which is primarily caused by lethal heart disorders resulting in structural and arrhythmogenic abnormalities, is one of the prevalent modes of death in most developed countries. Myocardial ischemia, mainly due to coronary artery disease, is the most common type of heart disease leading to SCD. However, postmortem diagnosis of SCD is frequently complicated by obscure histological evidence. Here, we show that certain mRNA species, namely those encoding hemoglobin A1/2 and B (Hba1/2 and Hbb, respectively) as well as pyruvate dehydrogenase kinase 4 (Pdk4), exhibit distinct postmortem expression patterns in the left ventricular free wall of SCD subjects when compared with their expression patterns in the corresponding tissues from control subjects with non-cardiac causes of death. Hba1/2 and Hbb mRNA expression levels were higher in ischemic SCD cases with acute myocardial infarction or ischemic heart disease without recent infarction, and even in cardiac death subjects without apparent pathological signs of heart injuries, than control subjects. By contrast, Pdk4 mRNA was expressed at lower levels in SCD subjects. In conclusion, we found that altered myocardial Hba1/2, Hbb, and Pdk4 mRNA expression patterns can be employed as molecular signatures of fatal cardiac dysfunction to forensically implicate SCD as the primary cause of death. PMID:24642708

  13. Simulation of voltage-sensitive optical signals in three-dimensional slabs of cardiac tissue: application to transillumination and coaxial imaging methods

    NASA Astrophysics Data System (ADS)

    Bernus, O.; Wellner, M.; Mironov, S. F.; Pertsov, A. M.

    2005-01-01

    Voltage-sensitive dyes are an important tool in visualizing electrical activity in cardiac tissue. Until today, they have mainly been applied in cardiac electrophysiology to subsurface imaging. In the present study, we assess different imaging methods used in optical tomography with respect to their effectiveness in visualizing 3D cardiac activity. To achieve this goal, we simulate optical signals produced by excitation fronts initiated at different depths inside the myocardial wall and compare their properties for various imaging modes. Specifically, we consider scanning and broad-field illumination, including trans- and epi-illumination. We focus on the lateral optical resolution and signal intensity, as a function of the source depth. Optical diffusion theory is applied to derive a computationally efficient approximation of the point-spread function and to predict voltage-sensitive signals. Computations were performed both for fluorescent and absorptive voltage-sensitive dyes. Among all the above-mentioned methods, fluorescent coaxial scanning yields the best resolution (<2.5 mm) and gives the most information about the intramural cardiac activity.

  14. [Clinical applications of MALDI imaging using sliced sections of formalin-fixed paraffin-embedded tissues and longitudinal sliced hairs].

    PubMed

    Nakanishi, Toyofumi; Ito, Minako; Ueda, Kazuhito; Wada, Shinichi; Fujioka, Shigekazu; Tsuji, Motomu; Takubo, Takayuki

    2012-02-01

    MALDI-imaging MS (IMS) with MSMS analysis is a new powerful tool for the identification of not only disease-related proteins in formalin-fixed paraffin-embedded (FFPE) tissue sections but also protein/peptides/drugs/medicine in fresh-frozen tissues. IMS is used to reveal the mass profiles and spatial distribution of proteins in tissue sections and/or digested peptides derived from deposited protein in pathologic organs and then MSMS analysis identifies the amino acid sequence of the detected proteins in the tissue section. Moreover, on-tissue digestion combined with the MALDI-IM-TOF-IMS approach allows a proteomics "bottom-up" strategy with clinical samples, especially perioperative isolated tissues and FFPE tissues conserved for a long time in a clinical sample bank. The mass barcode-like image (MBI) on a longitudinal sliced hair by IMS is used in the selected reaction monitoring mode for serially chronological monitoring and traceability every few hours after drug and medicine intake. The advances of quantitative MBI for sliced sections of hair allow a new universal standardized assessment of drugs and medicines throughout the drug history. PMID:22568093

  15. Time-resolved fluorescence imaging (TRFI) for direct immunofluorescence of PSA and alpha-1-antichymotrypsin in prostatic tissue sections.

    PubMed

    Bjartell, A; Siivola, P; Hulkko, S; Pettersson, K; Rundt, K; Lilja, H; Lövgren, T

    1999-05-01

    We have developed a direct immunofluorescence technique utilising chelates of the lanthanide ions europium and terbium conjugated to monoclonal IgGs (Mabs) against prostate-specific antigen (PSA) and alpha-1-antichymotrypsin (ACT) for the detection and quantification on the same tissue section. Strong signals without disturbance from tissue autofluorescence were demonstrated in paraffin sections of ten benign and six malignant prostate tissue specimens. The signal intensity increased linearly with the amount of labelled Mab until epitope saturation began. The highest concentrations of bound IgG in tissue sections were 27.3 fmol/pixel for ACT and 7.2 for PSA. Time-resolved fluorescence imaging (TRFI) offers an attractive method for histochemical studies based on specific and quantitative detection of fluorescent lanthanide chelates. PMID:12496823

  16. Efficient long-term survival of cell grafts after myocardial infarction with thick viable cardiac tissue entirely from pluripotent stem cells

    PubMed Central

    Matsuo, Takehiko; Masumoto, Hidetoshi; Tajima, Shuhei; Ikuno, Takeshi; Katayama, Shiori; Minakata, Kenji; Ikeda, Tadashi; Yamamizu, Kohei; Tabata, Yasuhiko; Sakata, Ryuzo; Yamashita, Jun K.

    2015-01-01

    Poor engraftment of cells after transplantation to the heart is a common and unresolved problem in the cardiac cell therapies. We previously generated cardiovascular cell sheets entirely from pluripotent stem cells with cardiomyocytes, endothelial cells and vascular mural cells. Though sheet transplantation showed a better engraftment and improved cardiac function after myocardial infarction, stacking limitation (up to 3 sheets) by hypoxia hampered larger structure formation and long-term survival of the grafts. Here we report an efficient method to overcome the stacking limitation. Insertion of gelatin hydrogel microspheres (GHMs) between each cardiovascular cell sheet broke the viable limitation via appropriate spacing and fluid impregnation with GHMs. Fifteen sheets with GHMs (15-GHM construct; >1 mm thickness) were stacked within several hours and viable after 1 week in vitro. Transplantation of 5-GHM constructs (≈2 × 106 of total cells) to a rat myocardial infarction model showed rapid and sustained functional improvements. The grafts were efficiently engrafted as multiple layered cardiovascular cells accompanied by functional capillary networks. Large engrafted cardiac tissues (0.8 mm thickness with 40 cell layers) successfully survived 3 months after TX. We developed an efficient method to generate thicker viable tissue structures and achieve long-term survival of the cell graft to the heart. PMID:26585309

  17. Engineered 3D bioimplants using elastomeric scaffold, self-assembling peptide hydrogel, and adipose tissue-derived progenitor cells for cardiac regeneration

    PubMed Central

    Soler-Botija, Carolina; Bagó, Juli R; Llucià-Valldeperas, Aida; Vallés-Lluch, Ana; Castells-Sala, Cristina; Martínez-Ramos, Cristina; Fernández-Muiños, Teresa; Chachques, Juan Carlos; Pradas, Manuel Monleón; Semino, Carlos E; Bayes-Genis, Antoni

    2014-01-01

    Contractile restoration of myocardial scars remains a challenge with important clinical implications. Here, a combination of porous elastomeric membrane, peptide hydrogel, and subcutaneous adipose tissue-derived progenitor cells (subATDPCs) was designed and evaluated as a bioimplant for cardiac regeneration in a mouse model of myocardial infarction. SubATDPCs were doubly transduced with lentiviral vectors to express bioluminescent-fluorescent reporters driven by constitutively active, cardiac tissue-specific promoters. Cells were seeded into an engineered bioimplant consisting of a scaffold (polycaprolactone methacryloyloxyethyl ester) filled with a peptide hydrogel (PuraMatrix™), and transplanted to cover injured myocardium. Bioluminescence and fluorescence quantifications showed de novo and progressive increases in promoter expression in bioactive implant-treated animals. The bioactive implant was well adapted to the heart, and fully functional vessels traversed the myocardium-bioactive implant interface. Treatment translated into a detectable positive effect on cardiac function, as revealed by echocardiography. Thus, this novel implant is a promising construct for supporting myocardial regeneration. PMID:24936221

  18. IFATS collection: Human adipose tissue-derived stem cells induce angiogenesis and nerve sprouting following myocardial infarction, in conjunction with potent preservation of cardiac function.

    PubMed

    Cai, Liying; Johnstone, Brian H; Cook, Todd G; Tan, Jian; Fishbein, Michael C; Chen, Peng-Sheng; March, Keith L

    2009-01-01

    The administration of therapeutic cell types, such as stem and progenitor cells, has gained much interest for the limitation or repair of tissue damage caused by a variety of insults. However, it is still uncertain whether the morphological and functional benefits are mediated predominantly via cell differentiation or paracrine mechanisms. Here, we assessed the extent and mechanisms of adipose-derived stromal/stem cells (ASC)-dependent tissue repair in the context of acute myocardial infarction. Human ASCs in saline or saline alone was injected into the peri-infarct region in athymic rats following left anterior descending (LAD) coronary artery ligation. Cardiac function and structure were evaluated by serial echocardiography and histology. ASC-treated rats consistently exhibited better cardiac function, by all measures, than control rats 1 month following LAD occlusion. Left ventricular (LV) ejection fraction and fractional shortening were improved in the ASC group, whereas LV remodeling and dilation were limited in the ASC group compared with the saline control group. Anterior wall thinning was also attenuated by ASC treatment, and post-mortem histological analysis demonstrated reduced fibrosis in ASC-treated hearts, as well as increased peri-infarct density of both arterioles and nerve sprouts. Human ASCs were persistent at 1 month in the peri-infarct region, but they were not observed to exhibit significant cardiomyocyte differentiation. Human ASCs preserve heart function and augment local angiogenesis and cardiac nerve sprouting following myocardial infarction predominantly by the provision of beneficial trophic factors. PMID:18772313

  19. The myocardial regenerative potential of three-dimensional engineered cardiac tissues composed of multiple human iPS cell-derived cardiovascular cell lineages.

    PubMed

    Masumoto, Hidetoshi; Nakane, Takeichiro; Tinney, Joseph P; Yuan, Fangping; Ye, Fei; Kowalski, William J; Minakata, Kenji; Sakata, Ryuzo; Yamashita, Jun K; Keller, Bradley B

    2016-01-01

    Human induced pluripotent stem cells (hiPSCs) are a robust source for cardiac regenerative therapy due to their potential to support autologous and allogeneic transplant paradigms. The in vitro generation of three-dimensional myocardial tissue constructs using biomaterials as an implantable hiPSC-derived myocardium provides a path to realize sustainable myocardial regeneration. We generated engineered cardiac tissues (ECTs) from three cellular compositions of cardiomyocytes (CMs), endothelial cells (ECs), and vascular mural cells (MCs) differentiated from hiPSCs. We then determined the impact of cell composition on ECT structural and functional properties. In vitro force measurement showed that CM+EC+MC ECTs possessed preferential electromechanical properties versus ECTs without vascular cells indicating that incorporation of vascular cells augmented tissue maturation and function. The inclusion of MCs facilitated more mature CM sarcomeric structure, preferential alignment, and activated multiple tissue maturation pathways. The CM+EC+MC ECTs implanted onto infarcted, immune tolerant rat hearts engrafted, displayed both host and graft-derived vasculature, and ameliorated myocardial dysfunction. Thus, a composition of CMs and multiple vascular lineages derived from hiPSCs and incorporated into ECTs promotes functional maturation and demonstrates myocardial replacement and perfusion relevant for clinical translation. PMID:27435115

  20. The myocardial regenerative potential of three-dimensional engineered cardiac tissues composed of multiple human iPS cell-derived cardiovascular cell lineages

    PubMed Central

    Masumoto, Hidetoshi; Nakane, Takeichiro; Tinney, Joseph P.; Yuan, Fangping; Ye, Fei; Kowalski, William J.; Minakata, Kenji; Sakata, Ryuzo; Yamashita, Jun K.; Keller, Bradley B.

    2016-01-01

    Human induced pluripotent stem cells (hiPSCs) are a robust source for cardiac regenerative therapy due to their potential to support autologous and allogeneic transplant paradigms. The in vitro generation of three-dimensional myocardial tissue constructs using biomaterials as an implantable hiPSC-derived myocardium provides a path to realize sustainable myocardial regeneration. We generated engineered cardiac tissues (ECTs) from three cellular compositions of cardiomyocytes (CMs), endothelial cells (ECs), and vascular mural cells (MCs) differentiated from hiPSCs. We then determined the impact of cell composition on ECT structural and functional properties. In vitro force measurement showed that CM+EC+MC ECTs possessed preferential electromechanical properties versus ECTs without vascular cells indicating that incorporation of vascular cells augmented tissue maturation and function. The inclusion of MCs facilitated more mature CM sarcomeric structure, preferential alignment, and activated multiple tissue maturation pathways. The CM+EC+MC ECTs implanted onto infarcted, immune tolerant rat hearts engrafted, displayed both host and graft-derived vasculature, and ameliorated myocardial dysfunction. Thus, a composition of CMs and multiple vascular lineages derived from hiPSCs and incorporated into ECTs promotes functional maturation and demonstrates myocardial replacement and perfusion relevant for clinical translation. PMID:27435115

  1. Micro-Raman spectroscopy a powerful technique to identify crocidolite and erionite fibers in tissue sections

    NASA Astrophysics Data System (ADS)

    Rinaudo, C.; Croce, A.; Allegrina, M.; Baris, I. Y.; Dogan, A.; Powers, A.; Rivera, Z.; Bertino, P.; Yang, H.; Gaudino, G.; Carbone, M.

    2013-05-01

    Exposure to mineral fibers such asbestos and erionite is widely associated with the development of lung cancer and pleural malignant mesothelioma (MM). Pedigree and mineralogical studies indicated that genetics may influence mineral fiber carcinogenesis. Although dimensions strongly impact on the fiber carcinogenic potential, also the chemical composition and the fiber is relevant. By using micro-Raman spectroscopy we show here persistence and identification of different mineral phases, directly on histopathological specimens of mice and humans. Fibers of crocidolite asbestos and erionite of different geographic areas (Oregon, US and Cappadocia, Turkey) were injected in mice intra peritoneum. MM developed in 10/15 asbestos-treated mice after 5 months, and in 8-10/15 erionite-treated mice after 14 months. The persistence of the injected fibers was investigated in pancreas, liver, spleen and in the peritoneal tissue. The chemical identification of the different phases occurred in the peritoneal cavity or at the organ borders, while only rarely fibers were localized in the parenchyma. Raman patterns allow easily to recognize crocidolite and erionite fibers. Microscopic analysis revealed that crocidolite fibers were frequently coated by ferruginous material ("asbestos bodies"), whereas erionite fibers were always free from coatings. We also analyzed by micro-Raman spectroscopy lung tissues, both from MM patients of the Cappadocia, where a MM epidemic developed because of environmental exposure to erionite, and from Italian MM patients with occupational exposure to asbestos. Our findings demonstrate that micro-Raman spectroscopy is technique able to identify mineral phases directly on histopathology specimens, as routine tissue sections prepared for diagnostic purpose. REFERENCES A.U. Dogan, M. Dogan. Environ. Geochem. Health 2008, 30(4), 355. M. Carbone, S. Emri, A.U. Dogan, I. Steele, M. Tuncer, HI. Pass, et al. Nat. Rev. Cancer. 2007, 7 (2),147. M. Carbone, Y

  2. Minocycline attenuates brain tissue levels of TNF-α produced by neurons after prolonged hypothermic cardiac arrest in rats

    PubMed Central

    Drabek, Tomas; Janata, Andreas; Wilson, Caleb D.; Stezoski, Jason; Janesko-Feldman, Keri; Tisherman, Samuel A.; Foley, Lesley M.; Verrier, Jonathan; Kochanek, Patrick M.

    2014-01-01

    Neuro-cognitive disabilities are a well-recognized complication of hypothermic circulatory arrest. We and others have reported that prolonged cardiac arrest (CA) produces neuronal death and microglial proliferation and activation that are only partially mitigated by hypothermia. Microglia, and possibly other cells, are suggested to elaborate tumor necrosis factor alpha (TNF-α) which can trigger neuronal death cascades and exacerbate edema after CNS insults. Minocycline is neuroprotective in some brain ischemia models in part by blunting the microglial response. We tested the hypothesis that minocycline would attenuate neuroinflammation as reflected by brain tissue levels of TNF-α after hypothermic CA in rats. Rats were subjected to rapid exsanguination, followed by a 6 min normothermic CA. Hypothermia (30 °C) was then induced by an aortic saline flush. After a total of 20 min CA, resuscitation was achieved via cardiopulmonary bypass (CPB). After 5 min reperfusion, minocycline (90 mg/kg; n=6) or vehicle (PBS; n=6) were given. Hypothermia (34 °C) was maintained for 6 h. Rats were sacrificed at 6 or 24 h. TNF-α was quantified (ELISA) in four brain regions (cerebellum, CEREB; cortex, CTX; hippocampus, HIP; striatum, STRI). Naïve rats (n=6) and rats subjected to the same anesthesia and CPB but no CA served as controls (n=6). Immunocytochemistry was used to localize TNF-α. Naïve rats and CPB controls had no detectable TNF-α in any brain region. CA markedly increased brain TNF-α. Regional differences were seen, with the highest TNF-α levels in striatum in CA groups (10-fold higher, P<0.05 vs. all other brain regions). TNF-α was undetectable at 24 h. Minocycline attenuated TNF-α levels in CTX, HIP and STRI (P<0.05). TNF-α showed unique co-localization with neurons. In conclusion, we report region-dependent early increases in brain TNF-α levels after prolonged hypothermic CA, with maximal increases in striatum. Surprisingly, TNF-α co-localized in neurons and

  3. Dendritic cell and macrophage staining by monoclonal antibodies in tissue sections and epidermal sheets.

    PubMed Central

    Flotte, T. J.; Springer, T. A.; Thorbecke, G. J.

    1983-01-01

    Mouse tissue sections were stained by monoclonal antibodies to macrophage antigens (Mac-1 (M1/70), Mac-2 (M3/38), Mac-3 (M3/84) with the use of immunoperoxidase. Mac-1 was located diffusely in the cytoplasm of round cells in a high percentage of alveolar macrophages, resident peritoneal and bone marrow cells, in splenic red pulp, and in rare perivascular cells in the thymus. Mac-1 was absent in epithelial cells and Langerhans cells. Mac-2 was strongly positive in many dendritic cells in the thymic medulla, more than the cortex, in paracortex and medulla of lymph nodes, sparing the follicles, and in the marginal zone of spleen. There were a few positive cells in germinal centers. Mac-2 was located in a low percentage of bone marrow and a high percentage of resident peritoneal cells. When positive in sections Mac-3 always showed granular cytoplasmic staining. Bone marrow showed a high percentage of cytoplasmic staining (greater than 50%), as compared with low surface staining (less than 1%). It was found in hematopoietic cells, and in all endothelium, including postcapillary venules and lining of sinuses. It was probable that the resulting dendritic staining pattern for Mac-3 in paracortex of lymph node, white and red pulp, thymic cortex, and medulla included dendritic cells other than endothelial cells. Alveolar macrophages and Kupffer cells were positive for Mac-2 and Mac-3. Mac-3 also stained bile canaliculi. Clearly different staining patterns were found in epithelial cells for Mac-2 and Mac-3 in kidney tubules, intestinal mucosal lining, bronchi, choroid plexus, and epidermis. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:6340516

  4. Qualitative and Quantitative Analysis of Histone Deacetylases in Kidney Tissue Sections.

    PubMed

    Ververis, Katherine; Marzully, Selly; Samuel, Chrishan S; Hewitson, Tim D; Karagiannis, Tom C

    2016-01-01

    Fluorescent microscope imaging technologies are increasing in their applications and are being used on a wide scale. However methods used to quantify the level of fluorescence intensity are often not utilized-perhaps given the result may be immediately seen, quantification of the data may not seem necessary. However there are a number of reasons given to quantify fluorescent images including the importance of removing potential bias in the data upon observation as well as quantification of large numbers of images gives statistical power to detect subtle changes in experiments. In addition discreet localization of a protein could be detected without selection bias that may not be detectable by eye. Such data will be deemed useful when detecting the levels of HDAC enzymes within cells in order to develop more effective HDAC inhibitor compounds for use against multiple diseased states. Hence, we discuss a methodology devised to analyze fluorescent images using Image J to detect the mean fluorescence intensity of the 11 metal-dependent HDAC enzymes using murine kidney tissue sections as an example. PMID:26676140

  5. Immunolabeling of thin sections of Drosophila tissues for transmission electron microscopy.

    PubMed

    McDonald, Kent L; Sharp, David J; Rickoll, Wayne

    2012-07-01

    The main advantage of electron microscopy (EM) for immunolabeling is resolution, but there is also another aspect that is often overlooked. For many investigators, the definitive image of an organelle is the one generated by EM. This is especially true for membranous organelles, with the possible exception of the nucleus and plant vacuoles. For example, references to the Golgi apparatus, smooth and rough endoplasmic reticulum, centriole, kinetochore, or mitochondrion typically bring to mind the images in an electron micrograph. The components of the cytoskeleton also have characteristic structural features that are associated with their EM image. Thus, it can be more effective for investigators to view gold particles superimposed over the image of a microtubule (MT) or mitochondrion using EM than to see bright dots or lines in the light microscope. This is especially true if the immunofluorescence image is of fixed cells. Here, we provide an overview of methods of EM immunolabeling used for localizing specific antigens on thin sections of Drosophila tissues. PMID:22753603

  6. Intensity-based signal separation algorithm for accuratequantification of clustered centrosomes in tissue sections

    SciTech Connect

    Fleisch, Markus C.; Maxell, Christopher A.; Kuper, Claudia K.; Brown, Erika T.; Parvin, Bahram; Barcellos-Hoff, Mary-Helen; Costes,Sylvain V.

    2006-03-08

    Centrosomes are small organelles that organize the mitoticspindle during cell division and are also involved in cell shape andpolarity. Within epithelial tumors, such as breast cancer, and somehematological tumors, centrosome abnormalities (CA) are common, occurearly in disease etiology, and correlate with chromosomal instability anddisease stage. In situ quantification of CA by optical microscopy ishampered by overlap and clustering of these organelles, which appear asfocal structures. CA has been frequently associated with Tp53 status inpremalignant lesions and tumors. Here we describe an approach toaccurately quantify centrosomes in tissue sections and tumors.Considering proliferation and baseline amplification rate the resultingpopulation based ratio of centrosomes per nucleus allow the approximationof the proportion of cells with CA. Using this technique we show that20-30 percent of cells have amplified centrosomes in Tp53 null mammarytumors. Combining fluorescence detection, deconvolution microscopy and amathematical algorithm applied to a maximum intensity projection we showthat this approach is superior to traditional investigator based visualanalysis or threshold-based techniques.

  7. Synthesis and tissue biodistribution of [{omega}-{sup 11}C]palmitic acid. A novel PET imagining agent for cardiac fatty acid metabolism

    SciTech Connect

    Buckman, B.O.; VanBrocklin, H.F.; Katzenellenbogen, J.A.; Dence, C.S.; Bergmann, S.R.; Welch, M.J.

    1994-12-31

    In order to diagnose patients with medium-chain acyl-CoA dehydrogenase deficiency with a noninvasive diagnostic technique such as positron emission tomography, they have developed a synthesis of [{omega}-{sup 11}C]palmitic acid. The radiochemical synthesis was achieved by coupling an alkylfuran Grignard reagent (7) with [{sup 11}C]methyl iodide, followed by rapid oxidative cleavage of the furan ring to the carboxylate using ruthenium tetraoxide. Tissue biodistribution studies in rags comparing [{omega}-{sup 11}C]palmitic acid and [1-{sup 11}C]palmitic acid show that the %ID/g and %ID/organ in the heart tissue after administration of [{omega}-{sup 11}C]palmitic acid is approximately 50% greater than after administration of [1-{sup 11}C]palmitic acid, due to the diminished metabolism of the [{omega}-{sup 11}C]palmitic acid. These studies show as well, low uptake in nontarget tissues (blood, lung, kidney, and muscle). PET images of a dog heart obtained after administration of [{omega}-{sup 11}C]- and [1-{sup 11}C]palmitic acid show virtually identical uptake and distribution in the myocardium. The differing cardiac washout of labeled palmitates measured by dynamic PET studies may allow diagnosis of disorders in cardiac fatty acid metabolism.

  8. Microscopic variations in interstitial and intracellular structure modulate the distribution of conduction delays and block in cardiac tissue with source–load mismatch

    PubMed Central

    Hubbard, Marjorie Letitia; Henriquez, Craig S.

    2012-01-01

    Aims Reentrant activity in the heart is often correlated with heterogeneity in both the intracellular structure and the interstitial structure surrounding cells; however, the combined effect of cardiac microstructure and interstitial resistivity in regions of source–load mismatch is largely unknown. The aim of this study was to investigate how microstructural variations in cell arrangement and increased interstitial resistivity influence the spatial distribution of conduction delays and block in poorly coupled regions of tissue. Methods and results Two-dimensional 0.6 cm × 0.6 cm computer models with idealized and realistic cellular structure were used to represent a monolayer of ventricular myocytes. Gap junction connections were distributed around the periphery of each cell at 10 μm intervals. Regions of source–load mismatch were added to the models by increasing the gap junction and interstitial resistivity in one-half of the tissue. Heterogeneity in cell shape and cell arrangement along the boundary between well-coupled and poorly coupled tissue increased variability in longitudinal conduction delays to as much as 10 ms before the onset of conduction block, resulting in wavefront breakthroughs with pronounced curvature at distinct points along the boundary. Increasing the effective interstitial resistivity reduced source–load mismatch at the transition boundary, which caused a decrease in longitudinal conduction delay and an increase in the number of wavefront breakthroughs. Conclusion Microstructural variations in cardiac tissue facilitate the formation of isolated sites of wavefront breakthrough that may enable abnormal electrical activity in small regions of diseased tissue to develop into more widespread reentrant activity. PMID:23104912

  9. Folic acid mitigated cardiac dysfunction by normalizing the levels of tissue inhibitor of metalloproteinase and homocysteine-metabolizing enzymes postmyocardial infarction in mice

    PubMed Central

    Qipshidze, Natia; Tyagi, Neetu; Sen, Utpal; Givvimani, Srikanth; Metreveli, Naira; Lominadze, David

    2010-01-01

    Myocardial infarction (MI) results in significant metabolic derangement, causing accumulation of metabolic by product, such as homocysteine (Hcy). Hcy is a nonprotein amino acid generated during nucleic acid methylation and demethylation of methionine. Folic acid (FA) decreases Hcy levels by remethylating the Hcy to methionine, by 5-methylene tetrahydrofolate reductase (5-MTHFR). Although clinical trials were inconclusive regarding the role of Hcy in MI, in animal models, the levels of 5-MTHFR were decreased, and FA mitigated the MI injury. We hypothesized that FA mitigated MI-induced injury, in part, by mitigating cardiac remodeling during chronic heart failure. Thus, MI was induced in 12-wk-old male C57BL/J mice by ligating the left anterior descending artery, and FA (0.03 g/l in drinking water) was administered for 4 wk after the surgery. Cardiac function was assessed by echocardiography and by a Millar pressure-volume catheter. The levels of Hcy-metabolizing enzymes, cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 5-MTHFR, were estimated by Western blot analyses. The results suggest that FA administered post-MI significantly improved cardiac ejection fraction and induced tissue inhibitor of metalloproteinase, CBS, CSE, and 5-MTHFR. We showed that FA supplementation resulted in significant improvement of myocardial function after MI. The study eluted the importance of homocysteine (Hcy) metabolism and FA supplementation in cardiovascular disease. PMID:20802128

  10. Cardiac Time Intervals by Tissue Doppler Imaging M-Mode: Normal Values and Association with Established Echocardiographic and Invasive Measures of Systolic and Diastolic Function

    PubMed Central

    Mogelvang, Rasmus; de Knegt, Martina Chantal; Olsen, Flemming Javier; Galatius, Søren; Jensen, Jan Skov

    2016-01-01

    Purpose To define normal values of the cardiac time intervals obtained by tissue Doppler imaging (TDI) M-mode through the mitral valve (MV). Furthermore, to evaluate the association of the myocardial performance index (MPI) obtained by TDI M-mode (MPITDI) and the conventional method of obtaining MPI (MPIConv), with established echocardiographic and invasive measures of systolic and diastolic function. Methods In a large community based population study (n = 974), where all are free of any cardiovascular disease and cardiovascular risk factors, cardiac time intervals, including isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT), and ejection time (ET) were obtained by TDI M-mode through the MV. IVCT/ET, IVRT/ET and the MPI ((IVRT+IVCT)/ET) were calculated. We also included a validation population (n = 44) of patients who underwent left heart catheterization and had the MPITDI and MPIConv measured. Results IVRT, IVRT/ET and MPI all increased significantly with increasing age in both genders (p<0.001 for all). IVCT, ET, IVRT/ET, and MPI differed significantly between males and females, displaying that women, in general exhibit better cardiac function. MPITDI was significantly associated with invasive (dP/dt max) and echocardiographic measures of systolic (LVEF, global longitudinal strain and global strainrate s) and diastolic function (e’, global strainrate e)(p<0.05 for all), whereas MPIConv was significantly associated with LVEF, e’ and global strainrate e (p<0.05 for all). Conclusion Normal values of cardiac time intervals differed between genders and deteriorated with increasing age. The MPITDI (but not MPIConv) is associated with most invasive and established echocardiographic measures of systolic and diastolic function. PMID:27093636

  11. Mast cell deficient W/Wv mice have lower serum IL-6 and less cardiac tissue necrosis than their normal littermates following myocardial ischemia-reperfusion.

    PubMed

    Bhattacharya, K; Farwell, K; Huang, M; Kempuraj, D; Donelan, J; Papaliodis, D; Vasiadi, M; Theoharides, T C

    2007-01-01

    Myocardial ischemia-reperfusion (IR) injury complicates all forms of coronary artery revascularization. Circulating interleukin-6 (IL-6) has been implicated in cell death following a variety of stimuli. Macrophages, platelets, neutrophils and the endothelium have been shown to release IL-6 after IR injury. Cardiac mast cells have been implicated in IR; however, their involvement has never been quantified. In this randomized, prospective study, we compared cardiac tissue susceptibility and serum IL-6 changes between mast cell deficient (W/Wv) mice and their normal littermates (+/+). Twenty-eight male W/Wv mice (n=14) and their +/+ littermates (n=14) were anaesthetized with 2.5% isoflurane. The left coronary artery (LCA) was ligated for 30 minutes or a sham procedure was performed. After 6 hours of reperfusion, the animals were sacrificed. The muscle viability was assessed on fresh whole-mount slices by nitroblue tetrazolium (NBT) histochemical assay and serum IL-6 concentrations measured by ELISA. Cardiac muscle viability was significantly higher in W/Wv mice than the +/+ mice. Serum IL-6 levels were higher in the +/+ sham mice (465 +/- 32 pg/ml, n=6) than the W/Wv mice (185 +/- 31 pg/ml, n=6), p < 0.001. The IL-6 levels increased significantly after reperfusion only in the +/+ mice (698 +/- 41 pg/ml, n=8, p = 0.001), while it remained similar in the W/Wv mice (202 +/- 48 pg/ml, n=8, p = 0.783). These results show that the absence of mast cells reduces the myocardial damage associated with IR injury. Furthermore, there is an attenuation in the inflammatory response, as measured by serum IL-6 levels, following this local insult. This finding entertains the prospect of developing prophylactic therapy--targeting selective inhibition of cardiac mast cell activation, in clinical situations involving medical or surgical myocardial revascularization. PMID:17346429

  12. In situ hybridization for the detection of rust fungi in paraffin embedded plant tissue sections

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rust fungi infect a wide range of plant species making them of particular interest to plant pathologists. In order to study the interactions between these important pathogenic fungi and their host plants it is useful to be able to differentiate fungal tissue from plant tissue. This can be accomplish...

  13. Rapid and simple method of photobleaching to reduce background autofluorescence in lung tissue sections.

    PubMed

    Kumar, B Santhosh; Sandhyamani, S; Nazeer, Shaiju S; Jayasree, R S

    2015-02-01

    Autofluorescence exhibited by tissues often interferes with immunofluorescence. Using imaging and spectral analysis, we observed remarkable reduction of autofluorescence of formalin fixed paraffin embedded tissues irradiated with light prior to incubation with immunofluorescent dyes. The technique of photobleaching offers significant improvement in the quality and specificity of immunofluorescence. This has the potential for better techniques for disease diagnosis. PMID:26040118

  14. Cardiac perception and cardiac control. A review.

    PubMed

    Carroll, D

    1977-12-01

    The evidence regarding specific cardiac perception and discrimination, and its relationship to voluntary cardiac control, is critically reviewed. Studies are considered in three sections, depending on the method used to assess cardiac perception: questionnaire assessment, discrimination procedures, and heartbeat tracking. The heartbeat tracking procedure would appear to suffer least from interpretative difficulties. Recommendations are made regarding the style of analysis used to assess heartbeat perception in such tracking tasks. PMID:348240

  15. Clinical evaluation of the flotrac/vigileo™ system for continuous cardiac output monitoring in patients undergoing regional anesthesia for elective cesarean section: a pilot study

    PubMed Central

    Auler, José Otavio C.; Torres, Marcelo L. A.; Cardoso, Mônica M.; Tebaldi, Thais C.; Schmidt, André P.; Kondo, Mario M.; Zugaib, Marcelo

    2010-01-01

    BACKGROUND: Spinal anesthesia for cesarean delivery may cause severe maternal hypotension and a decrease in cardiac output. Compared to assessment of cardiac output via a pulmonary artery catheter, the FloTrac/Vigileo™ system may offer a less invasive technique. The aim of this study was to evaluate cardiac output and other hemodynamic measurements made using the FloTrac/Vigileo™ system in patients undergoing spinal anesthesia for elective cesarean section. METHODS: A prospective study enrolling 10 healthy pregnant women was performed. Hemodynamic parameters were continuously obtained at 15 main points: admission to surgery (two baseline measurements), after preload, after spinal anesthesia administration and 4 time points thereafter (4, 6, 8 and 10 min after anesthesia), at skin and uterine incision, newborn and placental delivery, oxytocin administration, end of surgery, and recovery from anesthesia. Hemodynamic therapy was guided by mean arterial pressure, and vasopressors were used as appropriate to maintain baseline values. A repeated measures ANOVA was used for data analysis. RESULTS: There was a significant increase in heart rate and a decrease of stroke volume and stroke volume index up to 10 min after spinal anesthesia (P < 0.01). Importantly, stroke volume variation increased immediately after newborn delivery (P < 0.001) and returned to basal values at the end of surgery. Further hemodynamic parameters showed no significant changes over time. DISCUSSION AND CONCLUSIONS: No significant hemodynamic effects, except for heart rate and stroke volume changes, were observed in pregnant women managed with preload and vasopressors when undergoing elective cesarean section and spinal anesthesia. PMID:20835557

  16. Fiber alignment and coculture with fibroblasts improves the differentiated phenotype of murine embryonic stem cell-derived cardiomyocytes for cardiac tissue engineering.

    PubMed

    Parrag, Ian C; Zandstra, Peter W; Woodhouse, Kimberly A

    2012-03-01

    Embryonic stem cells (ESCs) are an important source of cardiomyocytes for regenerating injured myocardium. The successful use of ESC-derived cardiomyocytes in cardiac tissue engineering requires an understanding of the important scaffold properties and culture conditions to promote cell attachment, differentiation, organization, and contractile function. The goal of this work was to investigate how scaffold architecture and coculture with fibroblasts influences the differentiated phenotype of murine ESC-derived cardiomyocytes (mESCDCs). Electrospinning was used to process an elastomeric biodegradable polyurethane (PU) into aligned or unaligned fibrous scaffolds. Bioreactor produced mESCDCs were seeded onto the PU scaffolds either on their own or after pre-seeding the scaffolds with mouse embryonic fibroblasts (MEFs). Viable mESCDCs attached to the PU scaffolds and were functionally contractile in all conditions tested. Importantly, the aligned scaffolds led to the anisotropic organization of rod-shaped cells, improved sarcomere organization, and increased mESCDC aspect ratio (length-to-diameter ratio) when compared to cells on the unaligned scaffolds. In addition, pre-seeding the scaffolds with MEFs improved mESCDC sarcomere formation compared to mESCDCs cultured alone. These results suggest that both fiber alignment and pre-treatment of scaffolds with fibroblasts improve the differentiation of mESCDCs and are important parameters for developing engineered myocardial tissue constructs using ESC-derived cardiac cells. PMID:22006660

  17. Lactate Up-Regulates the Expression of Lactate Oxidation Complex-Related Genes in Left Ventricular Cardiac Tissue of Rats

    PubMed Central

    Gabriel-Costa, Daniele; da Cunha, Telma Fatima; Bechara, Luiz Roberto Grassmann; Fortunato, Rodrigo Soares; Bozi, Luiz Henrique Marchesi; Coelho, Marcele de Almeida; Barreto-Chaves, Maria Luiza; Brum, Patricia Chakur

    2015-01-01

    Background Besides its role as a fuel source in intermediary metabolism, lactate has been considered a signaling molecule modulating lactate-sensitive genes involved in the regulation of skeletal muscle metabolism. Even though the flux of lactate is significantly high in the heart, its role on regulation of cardiac genes regulating lactate oxidation has not been clarified yet. We tested the hypothesis that lactate would increase cardiac levels of reactive oxygen species and up-regulate the expression of genes related to lactate oxidation complex. Methods/Principal Findings Isolated hearts from male adult Wistar rats were perfused with control, lactate or acetate (20mM) added Krebs-Henseleit solution during 120 min in modified Langendorff apparatus. Reactive oxygen species (O2●-/H2O2) levels, and NADH and NADPH oxidase activities (in enriched microsomal or plasmatic membranes, respectively) were evaluated by fluorimetry while SOD and catalase activities were evaluated by spectrophotometry. mRNA levels of lactate oxidation complex and energetic enzymes MCT1, MCT4, HK, LDH, PDH, CS, PGC1α and COXIV were quantified by real time RT-PCR. Mitochondrial DNA levels were also evaluated. Hemodynamic parameters were acquired during the experiment. The key findings of this work were that lactate elevated cardiac NADH oxidase activity but not NADPH activity. This response was associated with increased cardiac O2●-/H2O2 levels and up-regulation of MCT1, MCT4, LDH and PGC1α with no changes in HK, PDH, CS, COXIV mRNA levels and mitochondrial DNA levels. Lactate increased NRF-2 nuclear expression and SOD activity probably as counter-regulatory responses to increased O2●-/H2O2. Conclusions Our results provide evidence for lactate-induced up-regulation of lactate oxidation complex associated with increased NADH oxidase activity and cardiac O2●-/H2O2 driving to an anti-oxidant response. These results unveil lactate as an important signaling molecule regulating components of

  18. A simple method for fixation and microdissection of frozen fresh tissue sections for molecular cytogenetic analysis of cancers.

    PubMed

    Huang, Q; Sacks, P G; Mo, J; McCormick, S A; Iacob, C E; Guo, L; Schaefer, S; Schantz, S P

    2005-01-01

    Microdissection has been widely used for procuring DNA from specific microscopic regions of formalin fixed, paraffin embedded tissue sections. We have developed a method for fixation and microdissection of frozen fresh biopsy tissue sections. Five micrometer frozen fresh tissue sections were fixed with ethanol and stored at room temperature. Well defined regions from hematoxylin and eosin (H & E) stained or unstained sections were briefly steamed and microdissected using a needle. The dissected tissue was digested with proteinase K and DNA was isolated. Whole genome amplifications were obtained by degenerate oligonucleotide primed polymerase chain reaction (DOP-PCR) from these samples. The reliability of this technique was demonstrated by comparing conventional comparative genomic hybridization (CGH) with DOP-PCR-CGH. The advantages of this method are that frozen fresh sections can be fixed easily and stored for more than 4 years, it is easy to microdissect and pick-up very minute regions (0.1 mm(2)), and it is rapid; microdissection and purification can be accomplished within 3 h. Using DNA from microdissected sections, DOP-PCR-CGH revealed genetic abnormalities more accurately than conventional CGH. Although this novel method was demonstrated using DOP-PCR-CGH, we believe that it will be useful for other genetic analyses of specific small regions and cell populations. We also observed whether storage time, H & E staining and crude DNA extracts affected the quality of amplified DNA. DNA integrity was maintained for at least 49 months in ethanol fixed sections that were stored at room temperature, but DNA was gradually degraded after one month if the ethanol fixed sections had been H & E stained and stored. When crude DNA extracts from H & E stained sections were used, the size of the DOP-PCR product was reduced. Our study suggests that ethanol fixed tissue sections may be stored at room temperature for at least 4 years without DNA degradation, the H & E stains may

  19. Structure, function and clinical relevance of the cardiac conduction system, including the atrioventricular ring and outflow tract tissues.

    PubMed

    Dobrzynski, Halina; Anderson, Robert H; Atkinson, Andrew; Borbas, Zoltan; D'Souza, Alicia; Fraser, John F; Inada, Shin; Logantha, Sunil J R J; Monfredi, Oliver; Morris, Gwilym M; Moorman, Anton F M; Nikolaidou, Thodora; Schneider, Heiko; Szuts, Viktoria; Temple, Ian P; Yanni, Joseph; Boyett, Mark R

    2013-08-01

    It is now over 100years since the discovery of the cardiac conduction system, consisting of three main parts, the sinus node, the atrioventricular node and the His-Purkinje system. The system is vital for the initiation and coordination of the heartbeat. Over the last decade, immense strides have been made in our understanding of the cardiac conduction system and these recent developments are reviewed here. It has been shown that the system has a unique embryological origin, distinct from that of the working myocardium, and is more extensive than originally thought with additional structures: atrioventricular rings, a third node (so called retroaortic node) and pulmonary and aortic sleeves. It has been shown that the expression of ion channels, intracellular Ca(2+)-handling proteins and gap junction channels in the system is specialised (different from that in the ordinary working myocardium), but appropriate to explain the functioning of the system, although there is continued debate concerning the ionic basis of pacemaking. We are beginning to understand the mechanisms (fibrosis and remodelling of ion channels and related proteins) responsible for dysfunction of the system (bradycardia, heart block and bundle branch block) associated with atrial fibrillation and heart failure and even athletic training. Equally, we are beginning to appreciate how naturally occurring mutations in ion channels cause congenital cardiac conduction system dysfunction. Finally, current therapies, the status of a new therapeutic strategy (use of a specific heart rate lowering drug) and a potential new therapeutic strategy (biopacemaking) are reviewed. PMID:23612425

  20. Analysis of erlotinib and its metabolites in rat tissue sections by MALDI quadrupole time-of-flight mass spectrometry.

    PubMed

    Signor, Luca; Varesio, Emmanuel; Staack, Roland F; Starke, Volkmar; Richter, Wolfgang F; Hopfgartner, Gérard

    2007-07-01

    A qualitative and quantitative analysis of erlotinib (RO0508231) and its metabolites was carried out on rat tissue sections from liver, spleen and muscle. Following oral administration at a dose of 5 mg/kg, samples were analyzed by matrix-assisted laser desorption ionization (MALDI) with mass spectrometry (MS) using an orthogonal quadrupole time-of-flight instrument. The parent compound was detected in all tissues analyzed. The metabolites following drug O-dealkylation could also be detected in liver sections. Sinapinic acid (SA) matrix combined with the dried-droplet method resulted in better conditions for our analysis on tissues. Drug quantitation was investigated by the standard addition method and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis on the tissue extracts. The presence of the parent compound and of its O-demethylated metabolites was confirmed in all tissue types and their absolute amounts calculated. In liver the intact drug was found to be 3.76 ng/mg tissue, while in spleen and muscle 6- and 30-fold lower values, respectively, were estimated. These results were compared with drug quantitation obtained by whole-body autoradiography, which was found to be similar. The potential for direct quantitation on tissue sections in the presence of an internal standard was also investigated using MALDI-MS. The use of alpha-cyano-4-hydroxycinnamic acid (CHCA) as the matrix resulted in better linearity for the calibration curves obtained with reference solutions of the drug when compared to SA, but on tissue samples no reliable quantitative analysis was possible owing to the large variability in the signal response. MS imaging experiments using MALDI in MS/MS mode allowed visualizing the distribution of the parent compound in liver and spleen tissues. By calculating the ratio between the total ion intensities of MS images for liver and spleen sections, a value of 6 : 1 was found, which is in good agreement with the quantitative data obtained

  1. Cardiac Rehabilitation

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Cardiac Rehabilitation? Cardiac rehabilitation (rehab) is a medically supervised program ... be designed to meet your needs. The Cardiac Rehabilitation Team Cardiac rehab involves a long-term commitment ...

  2. Effective Melanin Depigmentation of Human and Murine Ocular Tissues: An Improved Method for Paraffin and Frozen Sections

    PubMed Central

    Manicam, Caroline; Pitz, Susanne; Brochhausen, Christoph; Grus, Franz H.; Pfeiffer, Norbert; Gericke, Adrian

    2014-01-01

    Purpose The removal of excessive melanin pigments that obscure ocular tissue morphology is important to address scientific questions and for differential diagnosis of ocular tumours based on histology. Thus, the goal of the present study was to establish an effective and fast melanin bleaching method for paraffin and frozen mouse and human ocular tissues. Methods Paraffin-embedded and frozen ocular specimens from mice and human donors were subjected to bleaching employing two methods. The first employed potassium permanganate (KMnO4) with oxalic acid, and the second 10% hydrogen peroxide (H2O2). To determine optimal bleaching conditions, depigmentation was carried out at various incubation times. The effect of diluents used for 10% H2O2 was assessed using phosphate-buffered saline (PBS), and deionized water. Three different slide types and two fixatives, which were ice-cold acetone with 80% methanol, and 4% paraformaldehyde (PFA) were used to determine the optimal conditions for better tissue adherence during bleaching. All tissues were stained in hematoxylin and eosin for histological evaluation. Results Optimal bleaching was achieved using warm 10% H2O2 diluted in PBS at 65°C for 120 minutes. Chromium-gelatin-coated slides prevented tissue detachment. Adherence of cryosections was also improved with post-fixation using 4% PFA and overnight air-drying at RT after cryosectioning. Tissue morphology was preserved under these conditions. Conversely, tissues bleached in KMnO4/oxalic acid demonstrated poor depigmentation with extensive tissue damage. Conclusions Warm dilute H2O2 at 65°C for 120 minutes rapidly and effectively bleached both cryo- and paraffin sections of murine and human ocular tissues. PMID:25025426

  3. Separating spectral mixtures in hyperspectral image data using independent component analysis: validation with oral cancer tissue sections

    NASA Astrophysics Data System (ADS)

    Duann, Jeng-Ren; Jan, Chia-Ing; Ou-Yang, Mang; Lin, Chia-Yi; Mo, Jen-Feng; Lin, Yung-Jiun; Tsai, Ming-Hsui; Chiou, Jin-Chern

    2013-12-01

    Recently, hyperspectral imaging (HSI) systems, which can provide 100 or more wavelengths of emission autofluorescence measures, have been used to delineate more complete spectral patterns associated with certain molecules relevant to cancerization. Such a spectral fingerprint may reliably correspond to a certain type of molecule and thus can be treated as a biomarker for the presence of that molecule. However, the outcomes of HSI systems can be a complex mixture of characteristic spectra of a variety of molecules as well as optical interferences due to reflection, scattering, and refraction. As a result, the mixed nature of raw HSI data might obscure the extraction of consistent spectral fingerprints. Here we present the extraction of the characteristic spectra associated with keratinized tissues from the HSI data of tissue sections from 30 oral cancer patients (31 tissue samples in total), excited at two different wavelength ranges (330 to 385 and 470 to 490 nm), using independent and principal component analysis (ICA and PCA) methods. The results showed that for both excitation wavelength ranges, ICA was able to resolve much more reliable spectral fingerprints associated with the keratinized tissues for all the oral cancer tissue sections with significantly higher mean correlation coefficients as compared to PCA (p<0.001).

  4. AutoStitcher: An Automated Program for Efficient and Robust Reconstruction of Digitized Whole Histological Sections from Tissue Fragments

    NASA Astrophysics Data System (ADS)

    Penzias, Gregory; Janowczyk, Andrew; Singanamalli, Asha; Rusu, Mirabela; Shih, Natalie; Feldman, Michael; Stricker, Phillip D.; Delprado, Warick; Tiwari, Sarita; Böhm, Maret; Haynes, Anne-Maree; Ponsky, Lee; Viswanath, Satish; Madabhushi, Anant

    2016-07-01

    In applications involving large tissue specimens that have been sectioned into smaller tissue fragments, manual reconstruction of a “pseudo whole-mount” histological section (PWMHS) can facilitate (a) pathological disease annotation, and (b) image registration and correlation with radiological images. We have previously presented a program called HistoStitcher, which allows for more efficient manual reconstruction than general purpose image editing tools (such as Photoshop). However HistoStitcher is still manual and hence can be laborious and subjective, especially when doing large cohort studies. In this work we present AutoStitcher, a novel automated algorithm for reconstructing PWMHSs from digitized tissue fragments. AutoStitcher reconstructs (“stitches”) a PWMHS from a set of 4 fragments by optimizing a novel cost function that is domain-inspired to ensure (i) alignment of similar tissue regions, and (ii) contiguity of the prostate boundary. The algorithm achieves computational efficiency by performing reconstruction in a multi-resolution hierarchy. Automated PWMHS reconstruction results (via AutoStitcher) were quantitatively and qualitatively compared to manual reconstructions obtained via HistoStitcher for 113 prostate pathology sections. Distances between corresponding fiducials placed on each of the automated and manual reconstruction results were between 2.7%–3.2%, reflecting their excellent visual similarity.

  5. Cardiac optogenetics

    PubMed Central

    2013-01-01

    Optogenetics is an emerging technology for optical interrogation and control of biological function with high specificity and high spatiotemporal resolution. Mammalian cells and tissues can be sensitized to respond to light by a relatively simple and well-tolerated genetic modification using microbial opsins (light-gated ion channels and pumps). These can achieve fast and specific excitatory or inhibitory response, offering distinct advantages over traditional pharmacological or electrical means of perturbation. Since the first demonstrations of utility in mammalian cells (neurons) in 2005, optogenetics has spurred immense research activity and has inspired numerous applications for dissection of neural circuitry and understanding of brain function in health and disease, applications ranging from in vitro to work in behaving animals. Only recently (since 2010), the field has extended to cardiac applications with less than a dozen publications to date. In consideration of the early phase of work on cardiac optogenetics and the impact of the technique in understanding another excitable tissue, the brain, this review is largely a perspective of possibilities in the heart. It covers the basic principles of operation of light-sensitive ion channels and pumps, the available tools and ongoing efforts in optimizing them, overview of neuroscience use, as well as cardiac-specific questions of implementation and ideas for best use of this emerging technology in the heart. PMID:23457014

  6. A spiked tissue-based approach for quantification of phosphatidylcholines in brain section by MALDI mass spectrometry imaging.

    PubMed

    Jadoul, Laure; Longuespée, Rémi; Noël, Agnès; De Pauw, Edwin

    2015-03-01

    In the last few years, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has been successfully used to study the distribution of lipids within tissue sections. However, few efforts have been made to acquire reliable quantitative data regarding the localized concentrations of these molecules. Here we propose an approach based on brain homogenates for the quantification of phosphatidylcholines (PCs) in brain section by MALDI MSI. Homogenates were spiked with a range of PC(16:0 d31/18:1) concentrations. Sections from homogenates and intact brain were simultaneously prepared before being analyzed by MALDI MSI using a Fourier transform ion cyclotron resonance (FT-ICR) analyzer. Standard curves were generated from the signal intensity of the different PC(16:0 d31/18:1) ionic species ([M+H](+), [M+Na](+) and [M+K](+)) detected from the homogenate sections. Localized quantitative data were finally extracted by correlating the standard curves with the signal intensities of endogenous PC (especially PC(16:0/18:1)) ionic species detected on different areas of the brain section. They were consistent with quantitative values found in the literature. This work introduces a new method to take directly into account biological matrix effects for the quantification of lipids as well as other endogenous compounds, in tissue sections by MALDI MSI. PMID:25326885

  7. Fixing and sectioning tissue from the plant Kalanchoë daigremontiana.

    PubMed

    Garcês, Helena; Sinha, Neelima

    2009-10-01

    Tissue samples from Kalanchoë daigremontiana can be fixed for scanning electron microscopy (SEM), histology, and in situ hybridization using several common steps described in this protocol. All steps should be performed in the same manner for all three methods unless otherwise noted. PMID:20147046

  8. Cardiac Outcomes in Adult Survivors of Childhood Cancer Exposed to Cardiotoxic Therapy: A Cross-Sectional Study from the St. Jude Lifetime Cohort

    PubMed Central

    Mulrooney, Daniel A.; Armstrong, Gregory T.; Huang, Sujuan; Ness, Kirsten K.; Ehrhardt, Matthew J.; Joshi, Vijaya M.; Plana, Juan Carlos; Soliman, Elsayed Z.; Green, Daniel M.; Srivastava, Deokumar; Santucci, Aimee; Krasin, Matthew J.; Robison, Leslie L.; Hudson, Melissa M.

    2016-01-01

    Background Studies of cardiac disease among adult survivors of childhood cancer have generally relied upon self-reported or registry-based data. Objective Systematically assess cardiac outcomes among childhood cancer survivors Design Cross-sectional Setting St. Jude Children's Research Hospital Patients 1,853 adult survivors of childhood cancer, ≥18 years old, and ≥10 years from treatment with cardiotoxic therapy for childhood cancer. Measurements History/physical examination, fasting metabolic and lipid panels, echocardiogram, electrocardiogram (ECG), 6-minute walk test (6MWT) all collected at baseline evaluation. Results Half (52.3%) of the survivors were male, median age 8.0 years (range: 0-24) at cancer diagnosis, 31.0 years (18-60) at evaluation. Cardiomyopathy was present in 7.4% (newly identified at the time of evaluation in 4.7%), coronary artery disease (CAD) in 3.8% (newly identified in 2.2%), valvular regurgitation/stenosis in 28.0% (newly identified in 24.8%), and conduction/rhythm abnormalities in 4.6% (newly identified in 1.4%). Nearly all (99.7%) were asymptomatic. The prevalences of cardiac conditions increased with age at evaluation, ranging from 3-24% among those 30-39 years to 10-37% among those ≥40 years. On multivariable analysis, anthracycline exposure ≥250 mg/m2 increased the odds of cardiomyopathy (odds ratio [OR] 2.7, 95% CI 1.1-6.9) compared to anthracycline unexposed survivors. Radiation to the heart increased the odds of cardiomyopathy (OR 1.9 95% CI 1.1-3.7) compared to radiation unexposed survivors. Radiation >1500 cGy with any anthracycline exposure conferred the greatest odds for valve findings. Limitations 61% participation rate of survivors exposed to cardiotoxic therapies, which were limited to anthracyclines and cardiac-directed radiation. A comparison group and longitudinal assessments are not available. Conclusions Cardiovascular screening identified considerable subclinical disease among adult survivors of childhood

  9. Isoproterenol directs hair follicle-associated pluripotent (HAP) stem cells to differentiate in vitro to cardiac muscle cells which can be induced to form beating heart-muscle tissue sheets.

    PubMed

    Yamazaki, Aiko; Yashiro, Masateru; Mii, Sumiyuki; Aki, Ryoichi; Hamada, Yuko; Arakawa, Nobuko; Kawahara, Katsumasa; Hoffman, Robert M; Amoh, Yasuyuki

    2016-03-01

    Nestin-expressing hair-follicle-associated pluripotent (HAP) stem cells are located in the bulge area of the follicle. Previous studies have shown that HAP stem cells can differentiate to neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. HAP stem cells effected nerve and spinal cord regeneration in mouse models. Recently, we demonstrated that HAP stem cells differentiated to beating cardiac muscle cells. The differentiation potential to cardiac muscle cells was greatest in the upper part of the follicle. The beat rate of the cardiac muscle cells was stimulated by isoproterenol. In the present study, we observed that isoproterenol directs HAP stem cells to differentiate to cardiac muscle cells in large numbers in culture compared to HAP stem cells not supplemented with isoproterenol. The addition of activin A, bone morphogenetic protein 4, and basic fibroblast growth factor, along with isoproternal, induced the cardiac muscle cells to form tissue sheets of beating heart muscle cells. These results demonstrate that HAP stem cells have great potential to form beating cardiac muscle cells in tissue sheets. PMID:27104748

  10. [Algorithm study on the three-dimensional cardiac tissue based on the model of ventricular action potential].

    PubMed

    Zhang, Hong; Ming, Lequn; Jin, Yinbin; Li, Mingjun; Zhang, Zhenxi; Lin, Yang

    2010-02-01

    Cardiac reentry is one of the important factors to induce arrhythmias. It could lead to ventricular tachycardia (VT) or even fibrillation (VF), resulting in sudden cardiac death. With the wide use of computer in the quantitative study of electrophysiology, the three-dimensional virtual heart for simulations needs to be developed imminently in computer. In this paper, numerical algorithm of the model was studied. The three-dimensional model was constructed by integrating Luo-Rudy 1991 ventricular cell model and diffusion equation. The operator splitting method was employed to solve the model. The alternate direction iterative (ADI) format and seven-point centered difference method were used for the partial differential equation. And the discrete format with second-order accuracy was taken for the boundary conditions. The results showed that the ADI format and seven-point centered difference method both could successfully figure out the membrane potential and electrical activities with good numerical stability. However, computing consumption could be greatly reduced with the ADI format, implying that the ADI method with large time step was more powerful in numerical simulations. PMID:20337013

  11. Reverse Genetic Morpholino Approach Using Cardiac Ventricular Injection to Transfect Multiple Difficult-to-target Tissues in the Zebrafish Larva

    PubMed Central

    Konantz, Judith; Antos, Christopher L.

    2014-01-01

    The zebrafish is an important model to understand the cell and molecular biology of organ and appendage regeneration. However, molecular strategies to employ reverse genetics have not yet been adequately developed to assess gene function in regeneration or tissue homeostasis during larval stages after zebrafish embryogenesis, and several tissues within the zebrafish larva are difficult to target. Intraventricular injections of gene-specific morpholinos offer an alternative method for the current inability to genomically target zebrafish genes in a temporally controlled manner at these stages. This method allows for complete dispersion and subsequent incorporation of the morpholino into various tissues throughout the body, including structures that were formerly impossible to reach such as those in the larval caudal fin, a structure often used to noninvasively research tissue regeneration. Several genes activated during larval finfold regeneration are also present in regenerating adult vertebrate tissues, so the larva is a useful model to understand regeneration in adults. This morpholino dispersion method allows for the quick and easy identification of genes required for the regeneration of larval tissues as well as other physiological phenomena regulating tissue homeostasis after embryogenesis. Therefore, this delivery method provides a currently needed strategy for temporal control to the evaluation of gene function after embryogenesis.  PMID:24961304

  12. Combined in situ zymography, immunofluorescence, and staining of iron oxide particles in paraffin-embedded, zinc-fixed tissue sections.

    PubMed

    Haeckel, Akvile; Schoenzart, Lena; Appler, Franziska; Schnorr, Joerg; Taupitz, Matthias; Hamm, Bernd; Schellenberger, Eyk

    2012-01-01

    Superparamagnetic iron oxide particles are used as potent contrast agents in magnetic resonance imaging. In histology, these particles are frequently visualized by Prussian blue iron staining of aldehyde-fixed, paraffin-embedded tissues. Recently, zinc salt-based fixative was shown to preserve enzyme activity in paraffin-embedded tissues. In this study, we demonstrate that zinc fixation allows combining in situ zymography with fluorescence immunohistochemistry (IHC) and iron staining for advanced biologic investigation of iron oxide particle accumulation. Very small iron oxide particles, developed for magnetic resonance angiography, were applied intravenously to BALB/c nude mice. After 3 hours, spleens were explanted and subjected to zinc fixation and paraffin embedding. Cut tissue sections were further processed to in situ zymography, IHC, and Prussian blue staining procedures. The combination of in situ zymography as well as IHC with subsequent Prussian blue iron staining on zinc-fixed paraffin-embedded tissues resulted in excellent histologic images of enzyme activity, protease distribution, and iron oxide particle accumulation. The combination of all three stains on a single section allowed direct comparison with only moderate degradation of fluorescein isothiocyanate-labeled substrate. This protocol is useful for investigating the biologic environment of accumulating iron oxide particles, with excellent preservation of morphology. PMID:22954182

  13. Detection of Cell Proliferation Markers by Immunofluorescence Staining and Microscopy Imaging in Paraffin-Embedded Tissue Sections.

    PubMed

    Eminaga, Seda; Teekakirikul, Polakit; Seidman, Christine E; Seidman, Jonathan G

    2016-01-01

    This unit describes a step-by-step protocol to detect and quantify proliferating cells in paraffin-embedded tissue sections. Two well-established markers of proliferation (incorporation of BrdU into newly synthesized DNA and expression of the nuclear protein Ki67) are detected after antigen-retrieval and subsequent immunofluorescence staining and confocal microscopy. © 2016 by John Wiley & Sons, Inc. PMID:27366888

  14. Design of preservation solutions for universal tissue preservation in vivo: demonstration of efficacy in preclinical models of profound hypothermic cardiac arrest.

    PubMed

    Taylor, M J; Rhee, P; Chen, Z; Alam, H B

    2005-01-01

    The design of new solutions for the universal preservation of tissues is a quest that would facilitate multiple-organ harvesting from organ donors since current preservation solutions do not provide optimum preservation for all organs. In contrast, a new approach to bloodless surgery using hypothermic blood substitution (HBS) to protect the whole body during profound hypothermic circulatory arrest (clinical suspended animation) has focused on the development of a hybrid solution design with the objective of providing universal tissue preservation. In this study, a porcine model of uncontrolled lethal hemorrhage was employed. A combination of two new solutions, maintenance and purge, was used in a cardiopulmonary bypass (CPB) technique to affect profound hypothermia and prolonged cardiac arrest (60 min), with resuscitation after surgical repair of the vascular deficit induced to affect exsanguination. After rewarming and recovery, pigs were monitored for 6 weeks for neurological deficits, cognitive function (learning new skills), and organ dysfunction. All the normothermic control animals died (n = 10), whereas 90% (9 of 10) in the HBS group survived (P < .05). Moreover, all of the survivors were neurologically intact, displayed normal learning and memory capability, and had no long-term organ dysfunction. Histology of brains after 6 weeks revealed no ischemic damage in marked contrast to control animals, which all showed diffuse ischemic damage. The demonstrated efficacy of these synthetic, acellular HBS solutions for protection of all the tissues in the body during clinical suspended animation justifies their consideration for multiple-organ harvesting from cadaveric and living donors. PMID:15808626

  15. The study of simulated microgravity effects on cardiac myocytes using a 3D heart tissue-equivalent model encapsulated in alginate microbeads

    NASA Astrophysics Data System (ADS)

    Li, Yu; Tian, Weiming; Zheng, Hongxia; Yu, Lei; Zhang, Yao; Han, Fengtong

    Long duration spaceflight may increase the risk and occurrence of potentially life-threatening heart rhythm disturbances associated with alterations of cardiac myocytes, myocyte connec-tivity, and extracellular matrix resulting from prolonged exposure to zero-or low-gravity. For understanding of the effects of microgravity, either traditional 2-dimensional (2D) cell cultures of adherent cell populations or animal models were typically used. The 2D in vitro systems do not allow assessment of the dynamic effects of intercellular interactions within tissues, whereas potentially confounding factors tend to be overlooked in animal models. Therefore novel cell culture model representative of the cellular interactions and with extracellular matrix present in tissues needs to be used. In this study, 3D multi-cellular heart tissue-equivalent model was constructed by culturing neonatal rat myocardial cells in alginate microbeads for one week. With this model we studied the simulated microgravity effects on myocardiocytes by incubat-ing the microbeads in NASA rotary cell culture system with a rate of 15rpm. Cytoskeletal changes, mitochondrial membrane potential and reactive oxygen production were studied after incubating for 24h, 48h and 72h respectively. Compared with 3D ground-culture group, sig-nificant cytoskeleton depolymerization characterized by pseudo-feet disappearance, significant increase of mitochondrial membrane potential, and greater reactive oxygen production were observed in after incubating 24h, 48h, and 72h, in NASA system. The beating rate of 3D heart tissue-equivalent decreased significantly at 24h, and all the samples stopped beating after 48h incubation while the beating rate of control group did not change. This study indicated that mi-crogravity affects both the structure and function of myocardial cells. Our results suggest that a 3D heart tissue-equivalent model maybe better for attempting to elucidate the microgravity effects on myocardiocytes in

  16. Evaluation of Cardiac Autonomic Functions in Older Parkinson’s Disease Patients: a Cross-Sectional Study

    PubMed Central

    Yalcin, Ahmet; Atmis, Volkan; Cengiz, Ozlem Karaarslan; Cinar, Esat; Aras, Sevgi; Varli, Murat; Atli, Teslime

    2016-01-01

    In Parkinson’s disease (PD), non-motor symptoms may occur such as autonomic dysfunction. We aimed to evaluate both parasympathetic and sympathetic cardiovascular autonomic dysfunction in older PD cases. 84 PD cases and 58 controls, for a total of 142, participated in the study. Parasympathetic tests were performed using electrocardiography. Sympathetic tests were assessed by blood pressure measurement and 24-hour ambulatory blood pressure measurement. The prevalence of orthostatic hypotension in PD patients was 40.5% in PD patients and 24.1% in the control group (p> 0.05). The prevalence of postprandial hypotension was 47.9% in the PD group and 27.5% in the controls (p <0.05). The prevalence of impairment in heart rate response to deep breathing was 26.2% in the PD group and 6.9% in the control group (p <0.05). The prevalence of postprandial hypotension in PD with orthostatic hypotension was 94% and 16% in PD patients without orthostatic hypotension (p <0.05). The prevalence of impairment in heart rate response to deep breathing was 52.9% in PD patients with orthostatic hypotension and 8% in PD cases without orthostatic hypotension (p<0.05). The prevalence of impairment in heart rate response to postural change was 41% in PD cases with orthostatic hypotension and 12% in PD cases without orthostatic hypotension (p <0.05).Although there are tests for assessing cardiovascular autonomic function that are more reliable, they are more complicated, and evaluation of orthostatic hypotension by blood pressure measurement and cardiac autonomic tests by electrocardiography are recommended since these tests are cheap and easy. PMID:26816661

  17. Pharmacologically active microcarriers associated with thermosensitive hydrogel as a growth factor releasing biomimetic 3D scaffold for cardiac tissue-engineering.

    PubMed

    Karam, Jean-Pierre; Muscari, Claudio; Sindji, Laurence; Bastiat, Guillaume; Bonafè, Francesca; Venier-Julienne, Marie-Claire; Montero-Menei, N Claudia

    2014-10-28

    The challenge of tissue engineering of the infarcted heart is how to improve stem cell engraftment, survival, homing, and differentiation for myocardial repair. We here propose to integrate human adipose-derived stem cells (ADSCs) and pharmacologically active microcarriers (PAMs), a three-dimensional (3D) carrier of cells and growth factors, into an injectable hydrogel (HG), to obtain a system that stimulates the survival and/or differentiation of the grafted cells toward a cardiac phenotype. PAMs are biodegradable and non-cytotoxic poly(lactic-co-glycolic acid) (PLGA) microspheres conveying cells on their 3D surface that deliver continuously and in a controlled manner a growth factor (GF) acting on the transported cells and on the microenvironment to improve engraftment. The choice of the appropriate GF and its protection during the formulation process and delivery are essential. In this study two GFs, hepatocyte growth factor (HGF) and insulin-like growth factor (IGF-1), have been encapsulated under a solid state in order to limit their interaction with the polymer and conserve their integrity. GF precipitation conditions and release profile from PAMs have been first investigated before combining them to ADSCs. The released IGF-1 and HGF induced the protein synthesis of cardiac differentiation markers GATA4, Nkx2.5, cTnI and CX43 after 1week in vitro. Moreover, the GFs accelerated cell cycle progression, as suggested by the increased expression of Cyclin D1 mRNA and the widespread distribution of Ki67 protein. Integrating PAMs within the thermosensitive P407 hydrogel increased their elastic properties but decreased the transcription of most cardiac markers. In contrast, CX43 expression increased in ADSC-PAM-GF complexes embedded within the hydrogel compared to the ADSCs cultured alone in the absence of P407. These results suggest that particulate scaffolds releasing HGF and IGF-1 may be beneficial for applications in tissue-engineering strategies for myocardial

  18. Quantitative diagnosis of cervical neoplasia using fluorescence lifetime imaging on haematoxylin and eosin stained tissue sections.

    PubMed

    Gu, Jun; Fu, Chit Yaw; Ng, Beng Koon; Gulam Razul, Sirajudeen so; Lim, Soo Kim

    2014-07-01

    The use of conventional fluorescence microscopy for characterizing tissue pathological states is limited by overlapping spectra and the dependence on excitation power and fluorophore concentration. Fluorescence lifetime imaging microscopy (FLIM) can overcome these limitations due to its insensitivity to fluorophore concentration, excitation power and spectral similarity. This study investigates the diagnosis of early cervical cancer using FLIM and a neural network extreme learning machine classifier. A concurrently high sensitivity and specificity of 92.8% and 80.2%, respectively, were achieved. The results suggest that the proposed technique can be used to supplement the traditional histopathological examination of early cervical cancer. PMID:23281280

  19. Advantages of detecting monoclonal antibody binding to tissue sections with biotin and avidin reagents in Coplin jars.

    PubMed

    Bindl, J M; Warnke, R A

    1986-04-01

    We describe a method of biotin/avidin-peroxidase detection using second and third stage reagents in Coplin jars. This method allows a large quantity of sections to be stained simultaneously with a minimal amount of technical time involved. A wide range of mouse monoclonal antibodies of varying specificities and isotypes were used to stain both frozen and paraffin-embedded sections of various normal and neoplastic tissues. Three different biotinylated anti-mouse antibodies were tested, including F(ab')2 antibody fragments of one, followed by horseradish peroxidase conjugated avidin. All monoclonal antibodies employed gave good staining, using incubation times of 30-50 minutes. The staining was done during a mean period of 25 to 27 days with an average staining load of 500 sections per Coplin jar. PMID:2420169

  20. In Utero Exposure of Female CD-1 Mice to AZT and/or 3TC: I. Persistence of Microscopic Lesions in Cardiac Tissue

    PubMed Central

    Torres, Salina M.; March, Thomas H.; Carter, Meghan M.; McCash, Consuelo L.; Seilkop, Steven K.; Poirier, Miriam C.; Walker, Dale M.

    2010-01-01

    The current study was designed to delineate temporal changes in cardiomyocytes and mitochondria at the light and electron microscopic levels in hearts of mice exposed transplacentally to commonly used nucleoside analogs (NRTIs). Pregnant CD-1 mice were given 80 mg AZT/kg, 40 mg 3TC/kg, 80 mg AZT/kg plus 40 mg 3TC/kg, or vehicle alone during the last 7 days of gestation, and hearts from female mouse pups were examined at 13 and 26 weeks postpartum for histopathological or ultrastructural changes in cross-sections of both the ventricles and the interventricular septum. Using light microscopy and special staining techniques, transplacental exposure to AZT, 3TC, or AZT/3TC was shown to induce significant histopathological changes in myofibrils; these changes were more widespread at 13 weeks than at 26 weeks postpartum. While most light microscopic lesions resolved, some became more severe between 13 and 26 weeks postpartum. Transplacental NRTI exposure also resulted in progressive drug-specific changes in the number and ultrastructural integrity of cardiac mitochondria. These light and electron microscopic findings show that a subset of changes in cardiac mitochondria and myofibrils persisted and progressed months after transplacental exposure of an animal model to NRTIs, with combined AZT/3TC exposure yielding additive effects compared with either drug alone. PMID:20101476

  1. Stimulating endogenous cardiac repair

    PubMed Central

    Finan, Amanda; Richard, Sylvain

    2015-01-01

    The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration, a combination of these approaches could ameliorate the overall repair process to incorporate the participation of multiple cellular players. PMID:26484341

  2. Nanostructured substrate fabricated by sectioning tendon using a microtome for tissue engineering.

    PubMed

    Dai, Xiaoshu; Xu, Qiaobing

    2011-12-01

    This paper describes an efficient and versatile method for the fabrication of nanostructured substrates from a piece of tendon which comprises aligned collagen nanofibers. We used a microtome to generate the tendon slices (10-50  µm thick), which were used as a scaffold for guiding directional cell growth. Highly aligned and uniform monolayer cells sheets were obtained. The tendon slices were used as a master, and the nanostructures outlined by the bundles of collagen nanofibers were successfully transferred onto a polystyrene film using standard soft lithography. The cell growing on the nanostructured polystyrene substrate showed good adhesion and alignment. The technique developed here enables one to fabricate nanostructured substrates without using any traditional micro/nanofabrication tools. The nanostructured substrate, e.g. a slice of tendon, has excellent biocompatibility and relatively good mechanical stability, which makes this technique useful in constructing complicated 3D tissues. PMID:22101489

  3. Human brain receptor autoradiography using whole hemisphere sections: a general method that minimizes tissue artefacts

    SciTech Connect

    Quirion, R.; Robitaille, Y.; Martial, J.; Chabot, J.G.; Lemoine, P.; Pilapil, C.; Dalpe, M.

    1987-01-01

    A general method for the preparation of high-quality, mostly ice-crystal-artefact-free whole human brain hemisphere sections is described. Upon receipt, hemispheres are divided; one is then fixed in buffered 10% formalin for neuropathological analysis while the other is cut in 8-10-mm-thick coronal slices that are then rapidly frozen in 2-methylbutane at -40 degrees C (10-15 sec) before being placed in the brain bank at -80 degrees C. Such rapid freezing markedly decreases the formation of ice-crystal artefacts. Whole-hemisphere 20-micron thick sections are then cut and mounted onto lantern-type gelatin-coated slides. These sections are subsequently used for both qualitative and quantitative in vitro receptor autoradiography. Examples of data obtained are given by using various radioligands labelling classical neutrotransmitter, neuropeptide, enzyme, and ion channel receptor binding sites. This method should be useful for the obtention of various receptor maps in human brain. Such information could be most useful for in vivo receptor visualization studies using positron emission tomography (PET) scanning. It could also indicate if a given receptor population is specifically and selectively altered in certain brain diseases, eventually leading to the development of new therapeutic approaches.

  4. Avenanthramides are bioavailable and accumulate in hepatic, cardiac, and skeletal muscle tissue following oral gavage in rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avenanthramides (AVA), polyphenols found exclusively in oats (Avena sativa L.), may play a role in the anti-inflammatory and anti-atherogenic activity of oats. The bioavailability of AVA has been demonstrated previously, but its distribution at the organ and tissue level and the extent of conjugati...

  5. Appropriateness of Diagnostic Coronary Angiography as a Measure of Cardiac Ischemia Testing in Non-Emergency Patients – A Retrospective Cross-Sectional Analysis

    PubMed Central

    Chmiel, Corinne; Reich, Oliver; Signorell, Andri; Tandjung, Ryan; Rosemann, Thomas; Senn, Oliver

    2015-01-01

    Background Adequate application of guidelines concerning non-invasive ischemia testing (NIIT) could avoid inappropriate invasive testing in non-emergency situations. Hardly any data exists regarding frequency and appropriateness of diagnostic coronary angiography (CA). The aim of this study was to evaluate the proportion and predictors of patients without NIIT prior to elective purely diagnostic CA without therapeutic intervention. Methods Retrospective cross-sectional analysis of insurance claims data from 2012 and 2013. Patients <18 years, acute cardiac ischemia and emergency procedures and patients insured in a managed care model were excluded from analysis. The proportion of patients with NIIT procedures (stress-ECG, transthoracic echocardiography, stress echocardiography, scintigraphy, computer tomography, heart MRI) undertaken within two months before diagnostic CA was assessed. Multiple logistic regression analysis was applied to investigate independent determinants for receiving NIIT. Findings 2714 patients were included for analysis. 37.5% (1018) did not receive any NIIT before CA. When high risk patients (patients having received therapeutic cardiac intervention within one month after or 18 months prior to diagnostic CA, n = 766) were excluded 34.3% (669) did not receive NIIT before CA. High risk status as well as >6 chronic comorbidities were independently associated with a lower proportion of NIIT (p<0.0001, OR 0.607 and p = 0.0041, OR 0.648), when additionally controlled for age, sex, language area, insurance coverage, inpatient treatment, cardiovascular medication and lower number of chronic comorbidities. Age (p<0.05, OR 1.009) and intake of oral antiplatelet therapy (p<0.0001, OR 1.914) were independently associated with a higher proportion of NIIT when controlled for the mentioned cofactors. Conclusions Our data show that despite the existence of guidelines a substantial overuse of a potentially harmful and inappropriate diagnostic intervention is

  6. Noninvasive, near infrared spectroscopic-measured muscle pH and PO2 indicate tissue perfusion for cardiac surgical patients undergoing cardiopulmonary bypass

    NASA Technical Reports Server (NTRS)

    Soller, Babs R.; Idwasi, Patrick O.; Balaguer, Jorge; Levin, Steven; Simsir, Sinan A.; Vander Salm, Thomas J.; Collette, Helen; Heard, Stephen O.

    2003-01-01

    OBJECTIVE: To determine whether near infrared spectroscopic measurement of tissue pH and Po2 has sufficient accuracy to assess variation in tissue perfusion resulting from changes in blood pressure and metabolic demand during cardiopulmonary bypass. DESIGN: Prospective clinical study. SETTING: Academic medical center. SUBJECTS: Eighteen elective cardiac surgical patients. INTERVENTION: Cardiac surgery under cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: A near infrared spectroscopic fiber optic probe was placed over the hypothenar eminence. Reference Po2 and pH sensors were inserted in the abductor digiti minimi (V). Data were collected every 30 secs during surgery and for 6 hrs following cardiopulmonary bypass. Calibration equations developed from one third of the data were used with the remaining data to investigate sensitivity of the near infrared spectroscopic measurement to physiologic changes resulting from cardiopulmonary bypass. Near infrared spectroscopic and reference pH and Po2 measurements were compared for each subject using standard error of prediction. Near infrared spectroscopic pH and Po2 at baseline were compared with values during cardiopulmonary bypass just before rewarming commenced (hypotensive, hypothermic), after rewarming (hypotensive, normothermic) just before discontinuation of cardiopulmonary bypass, and at 6 hrs following cardiopulmonary bypass (normotensive, normothermic) using mixed-model analysis of variance. Near infrared spectroscopic pH and Po2 were well correlated with the invasive measurement of pH (R2 =.84) and Po2 (R 2 =.66) with an average standard error of prediction of 0.022 +/- 0.008 pH units and 6 +/- 3 mm Hg, respectively. The average difference between the invasive and near infrared spectroscopic measurement was near zero for both the pH and Po2 measurements. Near infrared spectroscopic Po2 significantly decreased 50% on initiation of cardiopulmonary bypass and remained depressed throughout the bypass and

  7. Cardiac Catheterization

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Cardiac Catheterization? Cardiac catheterization (KATH-eh-ter-ih-ZA-shun) is a ... disease. Doctors also can use ultrasound during cardiac catheterization to see blockages in the coronary arteries. Ultrasound ...

  8. Comparative analysis of numerical estimation methods of epithelial nerve fibers using tissue sections.

    PubMed

    Hilliges, M; Johansson, O

    1999-01-01

    The proper assessment of neuron numbers in the nervous system during physiological and pathological conditions, as well as following various treatments, has always been an important part of neuroscience. The present paper evaluates three methods for numerical estimates of nerves in epithelium: I) unbiased nerve fiber profile and nerve fiber fragment estimation methods, II) the traditional method of counting whole nerve fibers, and III) the nerve fiber estimation method. In addition, an unbiased nerve length estimation method was evaluated. Of these four methods, the nerve length per volume method was theoretically optimal, but more time-consuming than the others. The numbers obtained with the methods of nerve fiber profile, nerve fragment and nerve fiber estimation are dependent on the thickness of the epithelium and the sections as well as certain shape factors of the counted fiber. However for those, the actual counting can readily be performed in the microscope and is consequently quick and relatively inexpensive. The statistical analysis showed a very good correlation (R > 0.96) between the three numerical methods, meaning that basically any method could be used. However, dependent on theoretical and practical considerations and the correlation statistics, it may be concluded that the nerve fiber profile or fragment estimation methods should be employed if differences in epithelial and section thickness and the nerve fibers shape factors can be controlled. Such drawbacks are not inherent in the nerve length estimation method and, thus, it can generally be applied. PMID:10197065

  9. Localization and imaging of gangliosides in mouse brain tissue sections by laserspray ionization inlet.

    PubMed

    Richards, Alicia L; Lietz, Christopher B; Wager-Miller, James; Mackie, Ken; Trimpin, Sarah

    2012-07-01

    A new ionization method for the analysis of fragile gangliosides without undesired fragmentation or salt adduction is presented. In laserspray ionization inlet (LSII), the matrix/analyte sample is ablated at atmospheric pressure, and ionization takes place in the ion transfer capillary of the mass spectrometer inlet by a process that is independent of a laser wavelength or voltage. The softness of LSII allows the identification of gangliosides up to GQ1 with negligible sialic acid loss. This is of importance to the field of MS imaging, as undesired fragmentation has made it difficult to accurately map the spatial distribution of fragile ganglioside lipids in tissue. Proof-of-principle structural characterization of endogenous gangliosides using MS(n) fragmentation of multiply charged negative ions on a LTQ Velos and subsequent imaging of the GD1 ganglioside is demonstrated. This is the first report of multiply charged negative ions using inlet ionization. We find that GD1 is detected at higher levels in the mouse cortex and hippocampus compared with the thalamus. In LSII with the laser aligned in transmission geometry relative to the inlet, images were obtained in approximately 60 min using an inexpensive nitrogen laser. PMID:22262808

  10. Localization and imaging of gangliosides in mouse brain tissue sections by laserspray ionization inlet[S

    PubMed Central

    Richards, Alicia L.; Lietz, Christopher B.; Wager-Miller, James; Mackie, Ken; Trimpin, Sarah

    2012-01-01

    A new ionization method for the analysis of fragile gangliosides without undesired fragmentation or salt adduction is presented. In laserspray ionization inlet (LSII), the matrix/analyte sample is ablated at atmospheric pressure, and ionization takes place in the ion transfer capillary of the mass spectrometer inlet by a process that is independent of a laser wavelength or voltage. The softness of LSII allows the identification of gangliosides up to GQ1 with negligible sialic acid loss. This is of importance to the field of MS imaging, as undesired fragmentation has made it difficult to accurately map the spatial distribution of fragile ganglioside lipids in tissue. Proof-of-principle structural characterization of endogenous gangliosides using MSn fragmentation of multiply charged negative ions on a LTQ Velos and subsequent imaging of the GD1 ganglioside is demonstrated. This is the first report of multiply charged negative ions using inlet ionization. We find that GD1 is detected at higher levels in the mouse cortex and hippocampus compared with the thalamus. In LSII with the laser aligned in transmission geometry relative to the inlet, images were obtained in approximately 60 min using an inexpensive nitrogen laser. PMID:22262808

  11. Localization of telomerase hTERT protein in frozen sections of basal cell carcinomas (BCC) and tumor margin tissues.

    PubMed

    Fabricius, Eva-Maria; Kruse-Boitschenko, Ute; Khoury, Reem; Wildner, Gustav-Paul; Raguse, Jan-Dirk; Klein, Martin; Hoffmeister, Bodo

    2009-12-01

    In previous studies we demonstrated telomerase activity in frozen tissues from BCC and their tumor-free margins by the PCR ELISA. In this study we examined in the same frozen sections immunohistochemical presence of hTERT in the nucleus. After fixation in acetone and methanol followed by steaming we used for visualization the antigen-antibody reactions by APAAP. This was the best method of preparation of the frozen sections in our preliminary hTERT-study with squamous cell carcinomas. This study was supplemented with antibodies against Ki-67, nucleolin, common leucocyte antigen CD45 and mutated p53. The immunoreactive scores were determined and included the comparison with telomerase activity. The investigation of hTERT expression was performed in the tissues of 41 patients with BCC and control tissues of 14 patients without tumor. Eleven commercial antibodies were used for a nuclear staining of hTERT expression. With the anti-hTERT antibodies we looked for both satisfactory distribution and intensity of immunohistochemical labeling in the carcinomas and in the squamous epithelia of the tumor centers, of the tumor-free margins and of the control tissues. The hTERT expression in the BCC was distributed heterogeneously. The score values established by the anti-hTERT antibodies used were variably or significantly increased. In the stroma they tended to be negative, so we disregarded stroma hTERT. Proof of hTERT did not differ uniformly from telomerase activity. We compared the high with the lower median hTERT values in the Kaplan-Meier curve. Patients with lower hTERT scores in the center or tumor margin as shown by some of the antibodies suffered relapse earlier. Finally, we compared the hTERT expression in BCC tissues with the hTERT scores in HNSCC tissues from our previous study. Only one anti-hTERT antibody (our Ab 7) yielded significantly higher scores in BCC than in HNSCC. PMID:19885561

  12. Virtual tissue alignment and cutting plane definition – a new method to obtain optimal longitudinal histological sections

    PubMed Central

    Danz, J C; Habegger, M; Bosshardt, D D; Katsaros, C; Stavropoulos, A

    2014-01-01

    Histomorphometric evaluation of the buccal aspects of periodontal tissues in rodents requires reproducible alignment of maxillae and highly precise sections containing central sections of buccal roots; this is a cumbersome and technically sensitive process due to the small specimen size. The aim of the present report is to describe and analyze a method to transfer virtual sections of micro-computer tomographic (CT)-generated image stacks to the microtome for undecalcified histological processing and to describe the anatomy of the periodontium in rat molars. A total of 84 undecalcified sections of all buccal roots of seven untreated rats was analyzed. The accuracy of section coordinate transfer from virtual micro-CT slice to the histological slice, right–left side differences and the measurement error for linear and angular measurements on micro-CT and on histological micrographs were calculated using the Bland–Altman method, interclass correlation coefficient and the method of moments estimator. Also, manual alignment of the micro-CT-scanned rat maxilla was compared with multiplanar computer-reconstructed alignment. The supra alveolar rat anatomy is rather similar to human anatomy, whereas the alveolar bone is of compact type and the keratinized gingival epithelium bends apical to join the junctional epithelium. The high methodological standardization presented herein ensures retrieval of histological slices with excellent display of anatomical microstructures, in a reproducible manner, minimizes random errors, and thereby may contribute to the reduction of number of animals needed. PMID:24266502

  13. Evaluation of a tissue-engineered bovine pericardial patch in paediatric patients with congenital cardiac anomalies: initial experience with the ADAPT-treated CardioCel® patch

    PubMed Central

    Neethling, William M.L.; Strange, Geoff; Firth, Laura; Smit, Francis E.

    2013-01-01

    OBJECTIVES This study evaluated the safety, efficacy and clinical performance of the tissue-engineered ADAPT® bovine pericardial patch (ABPP) in paediatric patients with a range of congenital cardiac anomalies. METHODS In this single-centre, prospective, non-randomized clinical study, paediatric patients underwent surgery for insertion of the ABPP. Primary efficacy measures included early (<30 day) morbidity; incidence of device-related complications; haemodynamic performance derived from echocardiography assessment at 6- and 12-month follow-up and magnetic resonance imaging findings in 10 randomly selected patients at 12 months. Secondary measures included device-handling characteristics; shape and sizing characteristics and perioperative implant complications. The Aristotle complexity scoring system was used to score the complexity level of all surgical procedures. Patients completing the 12-month study were eligible to enter a long-term evaluation study. RESULTS Between April 2008 and September 2009, the ABPP was used in 30 paediatric patients. In the 30-day postoperative period, no graft-related morbidity was observed. In total, there were 5 deaths (2 in the 30-day postoperative period and 3 within the first 6 postoperative months). All deaths were deemed due to comorbid non-graft-related events. Echocardiography assessment at 6 and 12 months revealed intact anatomical and haemodynamically stable repairs without any visible calcification of the patch. Magnetic resonance imaging assessment in 10 patients at 12 months revealed no signs of calcification. Fisher's exact test demonstrated that patients undergoing more complex, higher risk surgical repairs (Aristotle complexity score >8) were significantly more likely to die (P = 0.0055, 58% survival compared with 100% survival for less complex surgical repairs). In 19 patients, echocardiographic data were available at 18–36 months with no evidence of device calcification, infection, thromboembolic events or

  14. A Discrete Electromechanical Model for Human Cardiac Tissue: Effects of Stretch-Activated Currents and Stretch Conditions on Restitution Properties and Spiral Wave Dynamics

    PubMed Central

    Weise, Louis D.; Panfilov, Alexander V.

    2013-01-01

    We introduce an electromechanical model for human cardiac tissue which couples a biophysical model of cardiac excitation (Tusscher, Noble, Noble, Panfilov, 2006) and tension development (adjusted Niederer, Hunter, Smith, 2006 model) with a discrete elastic mass-lattice model. The equations for the excitation processes are solved with a finite difference approach, and the equations of the mass-lattice model are solved using Verlet integration. This allows the coupled problem to be solved with high numerical resolution. Passive mechanical properties of the mass-lattice model are described by a generalized Hooke's law for finite deformations (Seth material). Active mechanical contraction is initiated by changes of the intracellular calcium concentration, which is a variable of the electrical model. Mechanical deformation feeds back on the electrophysiology via stretch-activated ion channels whose conductivity is controlled by the local stretch of the medium. We apply the model to study how stretch-activated currents affect the action potential shape, restitution properties, and dynamics of spiral waves, under constant stretch, and dynamic stretch caused by active mechanical contraction. We find that stretch conditions substantially affect these properties via stretch-activated currents. In constantly stretched medium, we observe a substantial decrease in conduction velocity, and an increase of action potential duration; whereas, with dynamic stretch, action potential duration is increased only slightly, and the conduction velocity restitution curve becomes biphasic. Moreover, in constantly stretched medium, we find an increase of the core size and period of a spiral wave, but no change in rotation dynamics; in contrast, in the dynamically stretching medium, we observe spiral drift. Our results may be important to understand how altered stretch conditions affect the heart's functioning. PMID:23527160

  15. High resolution image analysis of cell nuclei in tissue sections of primary and metastatic carcinomas.

    PubMed

    Theissig, F; Dimmer, V; Kunze, K D

    1986-01-01

    The present study examines whether certain histological tumour types can be differentiated on account of their nuclear image with the aid of automated image analysis. For karyometric investigations three tumour types (adenocarcinomas, squamous cell carcinomas and mammary carcinomas) were chosen, which occur frequently as occult primary tumours. From each type ten primary tumours with their corresponding lymph node metastases were examined. 100 cell nuclei were measured from each case using 4 micron thick paraffin sections stained with gallocyanin-chromalum. For each cell nucleus 21 contour and texture features were determined. Through the application of linear classifiers 41 out of 52 cases (25 primary tumours, 27 metastases) of these three tumour types were correctly classified. Eight cases could not be classified with certainty and only three cases were wrongly classified. In addition, within the group of adenocarcinomas differences due to localisation were detected which allow us to draw conclusions on the seat of the primary tumour. PMID:3019272

  16. Detection of Soluble ED-A+ Fibronectin and Evaluation as Novel Serum Biomarker for Cardiac Tissue Remodeling

    PubMed Central

    Ospel, Johanna; Neri, Dario; Pfeil, Alexander; Fritzenwanger, Michael; Figulla, Hans R.; Jung, Christian; Berndt, Alexander

    2016-01-01

    Background and Aims. Fibronectin containing the extra domain A (ED-A+ Fn) was proven to serve as a valuable biomarker for cardiac remodeling. The study was aimed at establishing an ELISA to determine ED-A+ Fn in serum of heart failure patients. Methods. ED-A+ Fn was quantified in serum samples from 114 heart failure patients due to ischemic (ICM, n = 44) and dilated (DCM, n = 39) cardiomyopathy as well as hypertensive heart disease (HHD, n = 31) compared to healthy controls (n = 12). Results. In comparison to healthy volunteers, heart failure patients showed significantly increased levels of ED-A+ Fn (p < 0.001). In particular in ICM patients there were significant associations between ED-A+ Fn serum levels and clinical parameters, for example, increased levels with rising NYHA class (p = 0.013), a negative correlation with left ventricular ejection fraction (p = 0.026, r: −0.353), a positive correlation with left atrial diameter (p = 0.008, r: 0.431), and a strong positive correlation with systolic pulmonary artery pressure (p = 0.002, r: 0.485). In multivariate analysis, ED-A+ Fn was identified as an independent predictor of an ischemic heart failure etiology. Conclusions. The current study could clearly show that ED-A+ Fn is a promising biomarker in cardiovascular diseases, especially in heart failure patients due to an ICM. We presented a valid ELISA method, which could be applied for further studies investigating the value of ED-A+ Fn.

  17. In Situ Hybridization Methods for Mouse Whole Mounts and Tissue Sections with and Without Additional β-Galactosidase Staining

    PubMed Central

    Komatsu, Yoshihiro; Kishigami, Satoshi; Mishina, Yuji

    2014-01-01

    In situ hybridization is a powerful method for detecting endogenous mRNA sequences in morphologically preserved samples. We provide in situ hybridization methods, which are specifically optimized for mouse embryonic samples as whole mounts and section tissues. Additionally, β-Galactosidase (β-gal) is a popular reporter for detecting the expression of endogenous or exogenous genes. We reveal that 6-chloro-3-indoxyl-β-D-galactopyranoside (S-gal) is a more sensitive substrate for β-gal activity than 5-bromo-4-chloro-3-indolyl-β-D-galactoside (X-gal). S-gal is advantageous where β-gal activity is limited including early stage mouse embryos. As a result of the increased sensitivity as well as the color compatibility of S-gal, we successfully combined β-gal staining using S-gal with in situ hybridization using DIG-labeled probes in both whole mounts and sections. PMID:24318810

  18. Association of Roadway Proximity with Fasting Plasma Glucose and Metabolic Risk Factors for Cardiovascular Disease in a Cross-Sectional Study of Cardiac Catheterization Patients

    PubMed Central

    Kraus, William E.; Blach, Colette; Haynes, Carol S.; Dowdy, Elaine; Miranda, Marie Lynn; Devlin, Robert B.; Diaz-Sanchez, David; Cascio, Wayne E.; Mukerjee, Shaibal; Stallings, Casson; Smith, Luther A.; Gregory, Simon G.; Shah, Svati H.; Hauser, Elizabeth R.; Neas, Lucas M.

    2015-01-01

    Background The relationship between traffic-related air pollution (TRAP) and risk factors for cardiovascular disease needs to be better understood in order to address the adverse impact of air pollution on human health. Objective We examined associations between roadway proximity and traffic exposure zones, as markers of TRAP exposure, and metabolic biomarkers for cardiovascular disease risk in a cohort of patients undergoing cardiac catheterization. Methods We performed a cross-sectional study of 2,124 individuals residing in North Carolina (USA). Roadway proximity was assessed via distance to primary and secondary roadways, and we used residence in traffic exposure zones (TEZs) as a proxy for TRAP. Two categories of metabolic outcomes were studied: measures associated with glucose control, and measures associated with lipid metabolism. Statistical models were adjusted for race, sex, smoking, body mass index, and socioeconomic status (SES). Results An interquartile-range (990 m) decrease in distance to roadways was associated with higher fasting plasma glucose (β = 2.17 mg/dL; 95% CI: –0.24, 4.59), and the association appeared to be limited to women (β = 5.16 mg/dL; 95% CI: 1.48, 8.84 compared with β = 0.14 mg/dL; 95% CI: –3.04, 3.33 in men). Residence in TEZ 5 (high-speed traffic) and TEZ 6 (stop-and-go traffic), the two traffic zones assumed to have the highest levels of TRAP, was positively associated with high-density lipoprotein cholesterol (HDL-C; β = 8.36; 95% CI: –0.15, 16.9 and β = 5.98; 95% CI: –3.96, 15.9, for TEZ 5 and 6, respectively). Conclusion Proxy measures of TRAP exposure were associated with intermediate metabolic traits associated with cardiovascular disease, including fasting plasma glucose and possibly HDL-C. Citation Ward-Caviness CK, Kraus WE, Blach C, Haynes CS, Dowdy E, Miranda ML, Devlin RB, Diaz-Sanchez D, Cascio WE, Mukerjee S, Stallings C, Smith LA, Gregory SG, Shah SH, Hauser ER, Neas LM. 2015. Association of roadway

  19. Cardiac Function and Short-Term Outcome in Patients with Acute Ischemic Stroke: A Cross-Sectional Study

    PubMed Central

    Mathias, Tiffany L.; Albright, Karen C.; Boehme, Amelia K; George, Alexander J.; Monlezun, Dominique; Jones, Erica; Beasley, T. Mark; Martin-Schild, Sheryl

    2013-01-01

    Few studies have investigated the relationship between left ventricular ejection fraction (LVEF) and functional outcome in ischemic stroke patients. The purpose of this study was to determine if a low LVEF in ischemic stroke was associated with functional outcome. A cross-sectional study was performed on ischemic stroke patients admitted to a single academic stroke center from June 2008 to December 2010. LVEF was determined using transthoracic or transesophageal echocardiography. Patients were categorized into three LVEF groups: severely low (<30%), moderately low (30-49%), and normal (>50%). Baseline demographics, in-hospital complications, and early outcomes were compared among LVEF groups using Chi-square, Wilcoxon rank sum, and logistic regression.590 patients met inclusion criteria (median age 65, 74% African American, 48% female). LVEF was normal in 79.8%, moderately low in 10.8%, and severely low in 9.3%. A smaller proportion of patients with severely low LVEF appeared to have good functional outcome compared to other groups (26% vs. 40% vs. 45%, p=0.028); however, this relationship was not significant after adjusting for age, baseline National Institute of Health Stroke Scale score and admission glucose (OR 0.6, 95% CI 0.3-1.3, p=0.216). Low LVEF was not an independent, significant predictor of short-term functional outcomes in ischemic stroke patients. PMID:24563872

  20. Quantitative Time-Resolved Fluorescence Imaging of Androgen Receptor and Prostate-Specific Antigen in Prostate Tissue Sections.

    PubMed

    Krzyzanowska, Agnieszka; Lippolis, Giuseppe; Helczynski, Leszek; Anand, Aseem; Peltola, Mari; Pettersson, Kim; Lilja, Hans; Bjartell, Anders

    2016-05-01

    Androgen receptor (AR) and prostate-specific antigen (PSA) are expressed in the prostate and are involved in prostate cancer (PCa). The aim of this study was to develop reliable protocols for reproducible quantification of AR and PSA in benign and malignant prostate tissue using time-resolved fluorescence (TRF) imaging techniques. AR and PSA were detected with TRF in tissue microarrays from 91 PCa patients. p63/ alpha-methylacyl-CoA racemase (AMACR) staining on consecutive sections was used to categorize tissue areas as benign or cancerous. Automated image analysis was used to quantify staining intensity. AR intensity was significantly higher in AMACR+ and lower in AMACR- cancer areas as compared with benign epithelium. The PSA intensity was significantly lower in cancer areas, particularly in AMACR- glands. The AR/PSA ratio varied significantly in the AMACR+ tumor cells as compared with benign glands. There was a trend of more rapid disease progression in patients with higher AR/PSA ratios in the AMACR- areas. This study demonstrates the feasibility of developing reproducible protocols for TRF imaging and automated image analysis to study the expression of AR and PSA in benign and malignant prostate. It also highlighted the differences in AR and PSA protein expression within AMACR- and AMACR+ cancer regions. PMID:27026295

  1. RootAnalyzer: A Cross-Section Image Analysis Tool for Automated Characterization of Root Cells and Tissues

    PubMed Central

    Chopin, Joshua; Laga, Hamid; Huang, Chun Yuan; Heuer, Sigrid; Miklavcic, Stanley J.

    2015-01-01

    The morphology of plant root anatomical features is a key factor in effective water and nutrient uptake. Existing techniques for phenotyping root anatomical traits are often based on manual or semi-automatic segmentation and annotation of microscopic images of root cross sections. In this article, we propose a fully automated tool, hereinafter referred to as RootAnalyzer, for efficiently extracting and analyzing anatomical traits from root-cross section images. Using a range of image processing techniques such as local thresholding and nearest neighbor identification, RootAnalyzer segments the plant root from the image’s background, classifies and characterizes the cortex, stele, endodermis and epidermis, and subsequently produces statistics about the morphological properties of the root cells and tissues. We use RootAnalyzer to analyze 15 images of wheat plants and one maize plant image and evaluate its performance against manually-obtained ground truth data. The comparison shows that RootAnalyzer can fully characterize most root tissue regions with over 90% accuracy. PMID:26398501

  2. Maternal cardiac metabolism in pregnancy.

    PubMed

    Liu, Laura X; Arany, Zolt

    2014-03-15

    Pregnancy causes dramatic physiological changes in the expectant mother. The placenta, mostly foetal in origin, invades maternal uterine tissue early in pregnancy and unleashes a barrage of hormones and other factors. This foetal 'invasion' profoundly reprogrammes maternal physiology, affecting nearly every organ, including the heart and its metabolism. We briefly review here maternal systemic metabolic changes during pregnancy and cardiac metabolism in general. We then discuss changes in cardiac haemodynamic during pregnancy and review what is known about maternal cardiac metabolism during pregnancy. Lastly, we discuss cardiac diseases during pregnancy, including peripartum cardiomyopathy, and the potential contribution of aberrant cardiac metabolism to disease aetiology. PMID:24448314

  3. Synthesis, characterization and antioxidant activity of a novel electroactive and biodegradable polyurethane for cardiac tissue engineering application.

    PubMed

    Baheiraei, Nafiseh; Yeganeh, Hamid; Ai, Jafar; Gharibi, Reza; Azami, Mahmoud; Faghihi, Faezeh

    2014-11-01

    There has been a growing trend towards applying conducting polymers for electrically excitable cells to increase electrical signal propagation within the cell-loaded substrates. A novel biodegradable electroactive polyurethane containing aniline pentamer (AP-PU) was synthesized and fully characterized by spectroscopic methods. To tune the physico-chemical properties and biocompatibility, the AP-PU was blended with polycaprolactone (PCL). The presence of electroactive moieties and the electroactivity behavior of the prepared films were confirmed by UV-visible spectroscopy and cyclic voltammetry. A conventional four probe analysis demonstrated the electrical conductivity of the films in the semiconductor range (~10(-5)S/cm). MTT assays using L929 mouse fibroblast and human umbilical vein endothelial cells (HUVECs) showed that the prepared blend (PB) displayed more cytocompatibility compared with AP-PU due to the introduction of a biocompatible PCL moiety. The in vitro cell culture also confirmed that PB was as supportive as tissue culture plate. The antioxidant activity of the AP-PU was proved using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay by employing UV-vis spectroscopy. In vitro degradation tests conducted in phosphate-buffered saline, pH7.4 and pH5.5, proved that the films were also biodegradable. The results of this study have highlighted the potential application of this bioelectroactive polyurethane as a platform substrate to study the effect of electrical signals on cell activities and to direct desirable cell function for tissue engineering applications. PMID:25280676

  4. Preventive effects of garlic (Allium sativum) on oxidative stress and histopathology of cardiac tissue in streptozotocin-induced diabetic rats.

    PubMed

    Naderi, R; Mohaddes, G; Mohammadi, M; Alihemmati, A; Badalzadeh, R; Ghaznavi, R; Ghyasi, R; Mohammadi, Sh

    2015-12-01

    Since some complications of diabetes mellitus may be caused or exacerbated by an oxidative stress, the protective effects of garlic (Allium sativum) were investigated in the blood and heart of streptozotocin-induced diabetic rats. Twenty-eight male Wistar rats were randomly divided into four groups: control, garlic, diabetic, and diabetic+garlic. Diabetes was induced by intraperitoneal (i.p.) injection of streptozotocin (50 mg/kg) in male rats. Rats were fed with raw fresh garlic homogenate (250 mg/kg) six days a week by gavage for a period of 6 weeks. At the end of the 6th week blood samples and heart tissues were collected and used for determination of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and histological evaluation. Induction of diabetes increased MDA levels in blood and homogenates of heart. In diabetic rats treated with garlic, MDA levels decreased in blood and heart homogenates. Treatment of diabetic rats with garlic increased SOD, GPX and CAT in blood and heart homogenates. Histopathological finding of the myocardial tissue confirmed a protective role for garlic in diabetic rats. Thus, the present study reveals that garlic may effectively modulate antioxidants status in the blood and heart of streptozotocin induced-diabetic rats. PMID:26690030

  5. Discrimination between basal cell carcinoma and hair follicles in skin tissue sections by Raman micro-spectroscopy

    NASA Astrophysics Data System (ADS)

    Larraona-Puy, M.; Ghita, A.; Zoladek, A.; Perkins, W.; Varma, S.; Leach, I. H.; Koloydenko, A. A.; Williams, H.; Notingher, I.

    2011-05-01

    Skin cancer is the most common human malignancy and basal cell carcinoma (BCC) represents approximately 80% of the non-melanoma cases. Current methods of treatment require histopathological evaluation of the tissues by qualified personnel. However, this method is subjective and in some cases BCC can be confused with other structures in healthy skin, including hair follicles. In this preliminary study, we investigated the potential of Raman micro-spectroscopy (RMS) to discriminate between hair follicles and BCC in skin tissue sections excised during Mohs micrographic surgery (MMS). Imaging and diagnosis of skin sections was automatically generated using ' a priori'-built spectral model based on LDA. This model had 90 ± 9% sensitivity and 85 ± 9% specificity for discrimination of BCC from dermis and epidermis. The model used selected Raman bands corresponding to the largest spectral differences between the Raman spectra of BCC and the normal skin regions, associated mainly with nucleic acids and collagen type I. Raman spectra corresponding to the epidermis regions of the hair follicles were found to be closer to those of healthy epidermis rather than BCC. Comparison between Raman spectral images and the gold standard haematoxylin and eosin (H&E) histopathology diagnosis showed good agreement. Some hair follicle regions were misclassified as BCC; regions corresponded mainly to the outermost layer of hair follicle (basal cells) which are expected to have higher nucleic acid concentration. This preliminary study shows the ability of RMS to distinguish between BCC and other tissue structures associated to healthy skin which can be confused with BCC due to their similar morphology.

  6. A review of recent methods for efficiently quantifying immunogold and other nanoparticles using TEM sections through cells, tissues and organs.

    PubMed

    Mayhew, Terry M; Mühlfeld, Christian; Vanhecke, Dimitri; Ochs, Matthias

    2009-04-01

    Detecting, localising and counting ultrasmall particles and nanoparticles in sub- and supra-cellular compartments are of considerable current interest in basic and applied research in biomedicine, bioscience and environmental science. For particles with sufficient contrast (e.g. colloidal gold, ferritin, heavy metal-based nanoparticles), visualization requires the high resolutions achievable by transmission electron microscopy (TEM). Moreover, if particles can be counted, their spatial distributions can be subjected to statistical evaluation. Whatever the level of structural organisation, particle distributions can be compared between different compartments within a given structure (cell, tissue and organ) or between different sets of structures (in, say, control and experimental groups). Here, a portfolio of stereology-based methods for drawing such comparisons is presented. We recognise two main scenarios: (1) section surface localisation, in which particles, exemplified by antibody-conjugated colloidal gold particles or quantum dots, are distributed at the section surface during post-embedding immunolabelling, and (2) section volume localisation (or full section penetration), in which particles are contained within the cell or tissue prior to TEM fixation and embedding procedures. Whatever the study aim or hypothesis, the methods for quantifying particles rely on the same basic principles: (i) unbiased selection of specimens by multistage random sampling, (ii) unbiased estimation of particle number and compartment size using stereological test probes (points, lines, areas and volumes), and (iii) statistical testing of an appropriate null hypothesis. To compare different groups of cells or organs, a simple and efficient approach is to compare the observed distributions of raw particle counts by a combined contingency table and chi-squared analysis. Compartmental chi-squared values making substantial contributions to total chi-squared values help identify where

  7. HistoStitcher© : An Interactive Program for Accurate and Rapid Reconstruction of Digitized Whole Histological Sections from Tissue Fragments

    PubMed Central

    Chappelow, Jonathan; Tomaszewski, John E.; Feldman, Michael; Shih, Natalie; Madabhushi, Anant

    2011-01-01

    We present an interactive program called HistoStitcher© for accurate and rapid reassembly of histology fragments into a pseudo-whole digitized histological section. HistoStitcher© provides both an intuitive graphical interface to assist the operator in performing the stitch of adjacent histology fragments by selecting pairs of anatomical landmarks, and a set of computational routines for determining and applying an optimal linear transformation to generate the stitched image. Reconstruction of whole histological sections from images of slides containing smaller fragments is required in applications where preparation of whole sections of large tissue specimens is not feasible or efficient, and such whole mounts are required to facilitate (a) disease annotation and (b) image registration with radiological images. Unlike manual reassembly of image fragments in a general purpose image editing program (such as Photoshop), HistoStitcher© provides memory efficient operation on high resolution digitized histology images and a highly flexible stitching process capable of producing more accurate results in less time. Further, by parameterizing the series of transformations determined by the stitching process, the stitching parameters can be saved, loaded at a later time, refined, or reapplied to multi-resolution scans, or quickly transmitted to another site. In this paper, we describe in detail the design of HistoStitcher© and the mathematical routines used for calculating the optimal image transformation, and demonstrate its operation for stitching high resolution histology quadrants of a prostate specimen to form a digitally reassembled whole histology section, for 8 different patient studies. To evaluate stitching quality, a 6 point scoring scheme, which assesses the alignment and continuity of anatomical structures important for disease annotation, is employed by three independent expert pathologists. For 6 studies compared with this scheme, reconstructed sections

  8. Adipose Tissue-Derived Mesenchymal Stromal Cells Protect Mice Infected with Trypanosoma cruzi from Cardiac Damage through Modulation of Anti-parasite Immunity

    PubMed Central

    Mesquita, Fernanda C. P.; Brasil, Guilherme V.; Rocha, Nazareth N.; Takiya, Christina M.; Lima, Ana Paula C. A.; Campos de Carvalho, Antonio C.; Goldenberg, Regina S.; Carvalho, Adriana B.

    2015-01-01

    Background Chagas disease, caused by the protozoan Trypanosoma cruzi (T.cruzi), is a complex disease endemic in Central and South America. It has been gathering interest due to increases in non-vectorial forms of transmission, especially in developed countries. The objective of this work was to investigate if adipose tissue-derived mesenchymal stromal cells (ASC) can alter the course of the disease and attenuate pathology in a mouse model of chagasic cardiomyopathy. Methodology/Principal Findings ASC were injected intraperitoneally at 3 days post-infection (dpi). Tracking by bioluminescence showed that cells remained in the abdominal cavity for up to 9 days after injection and most of them migrated to the abdominal or subcutaneous fat, an early parasite reservoir. ASC injection resulted in a significant reduction in blood parasitemia, which was followed by a decrease in cardiac tissue inflammation, parasitism and fibrosis at 30 dpi. At the same time point, analyses of cytokine release in cells isolated from the heart and exposed to T. cruzi antigens indicated an anti-inflammatory response in ASC-treated animals. In parallel, splenocytes exposed to the same antigens produced a pro-inflammatory response, which is important for the control of parasite replication, in placebo and ASC-treated groups. However, splenocytes from the ASC group released higher levels of IL-10. At 60 dpi, magnetic resonance imaging revealed that right ventricular (RV) dilation was prevented in ASC-treated mice. Conclusions/Significance In conclusion, the injection of ASC early after T. cruzi infection prevents RV remodeling through the modulation of immune responses. Lymphoid organ response to the parasite promoted the control of parasite burden, while the heart, a target organ of Chagas disease, was protected from damage due to an improved control of inflammation in ASC-treated mice. PMID:26248209

  9. Is cardiac tissue more susceptible than lung to oxidative effects induced by chronic nasotropic instillation of residual oil fly ash (ROFA)?

    PubMed

    Damiani, Roberto Marques; Piva, Marcella Ody; Petry, Marcelo Rafael; Saldiva, Paulo Hilário Nascimento; Tavares Duarte de Oliveira, Alexandre; Rhoden, Cláudia Ramos

    2012-09-01

    The current study aimed to determine the role of oxidants in cardiac and pulmonary toxicities induced by chronic exposure to ROFA. Eighty Wistar rats were divided into four groups: G1 (10 µL Saline), G2 (ROFA 50 µg/10 µL), G3 (ROFA 250 µg/10 µL) and G4 (ROFA 500 µg/10 µL). Rats received ROFA by nasotropic instillation for 90 days. After that, they were euthanized and bronchoalveolar lavage (BAL) was performed for total count of leukocytes, protein and lactate dehydrogenase (LDH) determinations. Lungs and heart were removed to measure lipid peroxidation (MDA), catalase (CAT) and superoxide dismutase (SOD) activity. BAL presented an increase in leukocytes count in G4 in comparison to the Saline group (p = 0.019). In lung, MDA level was not modified by ROFA, while CAT was higher in G4 when compared to all other groups (p = 0.013). In heart, G4 presented an increase in MDA (p = 0.016) and CAT (p = 0.027) levels in comparison to G1. The present study demonstrated cardiopulmonary oxidative changes after a chronic ROFA exposure. More specifically, the heart tissue seems to be more susceptible to oxidative effects of long-term exposure to ROFA than the lung. PMID:22563929

  10. Effects of Pacing Site and Stimulation History on Alternans Dynamics and the Development of Complex Spatiotemporal Patterns in Cardiac Tissue

    PubMed Central

    Gizzi, Alessio; Cherry, Elizabeth M.; Gilmour, Robert F.; Luther, Stefan; Filippi, Simonetta; Fenton, Flavio H.

    2013-01-01

    Alternans of action potential duration has been associated with T wave alternans and the development of arrhythmias because it produces large gradients of repolarization. However, little is known about alternans dynamics in large mammalian hearts. Using optical mapping to record electrical activations simultaneously from the epicardium and endocardium of 9 canine right ventricles, we demonstrate novel arrhythmogenic complex spatiotemporal dynamics. (i) Alternans predominantly develops first on the endocardium. (ii) The postulated simple progression from normal rhythm to concordant to discordant alternans is not always observed; concordant alternans can develop from discordant alternans as the pacing period is decreased. (iii) In contrast to smaller tissue preparations, multiple stationary nodal lines may exist and need not be perpendicular to the pacing site or to each other. (iv) Alternans has fully three-dimensional dynamics and the epicardium and endocardium can show significantly different dynamics: multiple nodal surfaces can be transmural or intramural and can form concave/convex surfaces resulting in islands of discordant alternans. (v) The complex spatiotemporal patterns observed during alternans are very sensitive to both the site of stimulation and the stimulation history. Alternans in canine ventricles not only exhibit larger amplitudes and persist for longer cycle length regimes compared to those found in smaller mammalian hearts, but also show novel dynamics not previously described that enhance dispersion and show high sensitivity to initial conditions. This indicates some underlying predisposition to chaos and can help to guide the design of new drugs and devices controlling and preventing arrhythmic events. PMID:23637684

  11. The benefits of the Atlas of Human Cardiac Anatomy website for the design of cardiac devices.

    PubMed

    Spencer, Julianne H; Quill, Jason L; Bateman, Michael G; Eggen, Michael D; Howard, Stephen A; Goff, Ryan P; Howard, Brian T; Quallich, Stephen G; Iaizzo, Paul A

    2013-11-01

    This paper describes how the Atlas of Human Cardiac Anatomy website can be used to improve cardiac device design throughout the process of development. The Atlas is a free-access website featuring novel images of both functional and fixed human cardiac anatomy from over 250 human heart specimens. This website provides numerous educational tutorials on anatomy, physiology and various imaging modalities. For instance, the 'device tutorial' provides examples of devices that were either present at the time of in vitro reanimation or were subsequently delivered, including leads, catheters, valves, annuloplasty rings and stents. Another section of the website displays 3D models of the vasculature, blood volumes and/or tissue volumes reconstructed from computed tomography and magnetic resonance images of various heart specimens. The website shares library images, video clips and computed tomography and MRI DICOM files in honor of the generous gifts received from donors and their families. PMID:24195457

  12. Minimum slice spacing required to reconstruct 3D shape for serial sections of breast tissue for comparison with medical imaging

    NASA Astrophysics Data System (ADS)

    Reis, Sara; Eiben, Bjoern; Mertzanidou, Thomy; Hipwell, John; Hermsen, Meyke; van der Laak, Jeroen; Pinder, Sarah; Bult, Peter; Hawkes, David

    2015-03-01

    There is currently an increasing interest in combining the information obtained from radiology and histology with the intent of gaining a better understanding of how different tumour morphologies can lead to distinctive radiological signs which might predict overall treatment outcome. Relating information at different resolution scales is challenging. Reconstructing 3D volumes from histology images could be the key to interpreting and relating the radiological image signal to tissue microstructure. The goal of this study is to determine the minimum sampling (maximum spacing between histological sections through a fixed surgical specimen) required to create a 3D reconstruction of the specimen to a specific tolerance. We present initial results for one lumpectomy specimen case where 33 consecutive histology slides were acquired.

  13. Expression of blood group antigens in urinary tract tumours: prospective fluorescence study using cryostat sections of fresh frozen tissues.

    PubMed Central

    Thorpe, S J; Abel, P; Henderson, D; Jones, N; Feizi, T

    1986-01-01

    Cryostat sections of fresh frozen tissues were used in a prospective study of blood group H and A antigen fluorescence in 73 transitional cell carcinomas of the bladder. The aim was to evaluate antigen expression without subjecting the tumour tissues to organic solvents that extract blood group active glycolipids. Deletion of the genetically predicted antigen was twice as common in tumours of pT1 or greater stage than those of pTa stage and also twice as common in poorly differentiated than in moderately well differentiated tumours. The considerable heterogeneity and overlap, however, in patterns of reactivity in tumours of various histopathological stages and grades and the effect of secretor status on antigenicity meant that there was no obvious antigenic feature that correlated precisely with invasive stage or differentiation grade. It remains to be determined whether the antigen positive and antigen negative tumours represent different disease entities with differing clinical courses. Our results indicate, however, that studies of the blood group antigens in urinary tract tumours are more likely to be of value in research into biochemical disorders in the neoplastic process than in routine clinical assessment as a guide to treatment. Images Fig 1 Fig 2 Fig 3 PMID:3540013

  14. Quantitative mass spectrometry imaging of small-molecule neurotransmitters in rat brain tissue sections using nanospray desorption electrospray ionization.

    PubMed

    Bergman, Hilde-Marléne; Lundin, Erik; Andersson, Malin; Lanekoff, Ingela

    2016-06-01

    Small molecule neurotransmitters are essential for the function of the nervous system, and neurotransmitter imbalances are often connected to neurological disorders. The ability to quantify such imbalances is important to provide insights into the biochemical mechanisms underlying the disorder. This proof-of-principle study presents online quantification of small molecule neurotransmitters, specifically acetylcholine, γ-aminobutyric acid (GABA) and glutamate, in rat brain tissue sections using nanospray desorption electrospray ionization (nano-DESI) mass spectrometry imaging. By incorporating deuterated internal standards in the nano-DESI solvent we show identification, accurate mapping, and quantification of these small neurotransmitters in rat brain tissue without introducing any additional sample preparation steps. We find that GABA is about twice as abundant in the medial septum-diagonal band complex (MSDB) as in the cortex, while glutamate is about twice as abundant in the cortex as compared to the MSDB. The study shows that nano-DESI is well suited for imaging of small molecule neurotransmitters in health and disease. PMID:26859000

  15. High affinity ( sup 3 H)glibenclamide binding sites in rat neuronal and cardiac tissue: Localization and developmental characteristics

    SciTech Connect

    Miller, J.A.; Velayo, N.L.; Dage, R.C.; Rampe, D. )

    1991-01-01

    We examined the binding of the antidiabetic sulfonylurea (3H) glibenclamide to rat brain and heart membranes. High affinity binding was observed in adult rat forebrain (Kd = 137.3 pM, maximal binding site density = 91.8 fmol/mg of protein) and ventricle (Kd = 77.1 pM, maximal binding site density = 65.1 fmol/mg of protein). Binding site density increased approximately 250% in forebrain membranes during postnatal development but was constant in ventricular membranes. Quantitative autoradiography was used to examine the regional distribution of (3H) glibenclamide binding sites in sections from rat brain, spinal cord and heart. The greatest density of binding in adult brain was found in the substantia nigra and globus pallidus, whereas the other areas displayed heterogenous binding. In agreement with the membrane binding studies, 1-day-old rat brain had significantly fewer (3H)glibenclamide binding sites than adult brain. Additionally, the pattern of distribution of these sites was qualitatively different from that of the adult. In adult rat spinal cord, moderate binding densities were observed in spinal cord gray and displayed a rostral to caudal gradient. In adult rat heart, moderate binding densities were observed and the sites were distributed homogeneously. In conclusion, significant development of (3H)glibenclamide binding sites was seen in the brain but not the heart during postnatal maturation. Furthermore, a heterogeneous distribution of binding sites was observed in both the brain and spinal cord of adult rats.

  16. Effects of Detergents on the Redistribution of Gangliosides and GPI-anchored Proteins in Brain Tissue Sections

    PubMed Central

    Heffer-Lauc, Marija; Viljetiæ, Barbara; Vajn, Katarina; Schnaar, Ronald L.; Lauc, Gordan

    2008-01-01

    SUMMARY Gangliosides and glycosylphosphatidylinositol (GPI)-anchored proteins contain lipid tails that tether them to the outer side of the cell membrane. This mode of association with the cell membrane enables them to take part in the organization of lipid rafts, but it also permits gangliosides and GPI-anchored proteins to be actively released from one cell and inserted into the membrane of another cell. Recently, we reported that under conditions of lipid raft isolation, Triton X-100 causes significant redistribution of both gangliosides and GPI-anchored proteins. Aiming to find a less disruptive detergent, we evaluated the effects of CHAPS, Saponin, deoxycholic acid, Trappsol, Tween 20, Triton X-100, Brij 96V, Brij 98, and SDS on brain tissue sections. At room temperature, all detergents (1% concentration) extracted significant amounts of both gangliosides and Thy-1. At 4C, the extraction was weaker, but Triton X-100, CHAPS, and deoxycholic acid caused significant redistribution of GD1a and Thy-1 from gray matter into the white matter. Both redistribution and extraction were significantly augmented when sections were incubated with detergents in the presence of primary antibodies. Of the nine tested detergents, none is the ideal choice. However, Brij 96V appears to be able to sufficiently reveal myelin epitopes while causing the least amount of artifacts. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials. PMID:17409378

  17. Conductive carbon tape used for support and mounting of both whole animal and fragile heat-treated tissue sections for MALDI MS imaging and quantitation.

    PubMed

    Goodwin, Richard J A; Nilsson, Anna; Borg, Daniel; Langridge-Smith, Pat R R; Harrison, David J; Mackay, C Logan; Iverson, Suzanne L; Andrén, Per E

    2012-08-30

    Analysis of whole animal tissue sections by MALDI MS imaging (MSI) requires effective sample collection and transfer methods to allow the highest quality of in situ analysis of small or hard to dissect tissues. We report on the use of double-sided adhesive conductive carbon tape during whole adult rat tissue sectioning of carboxymethyl cellulose (CMC) embedded animals, with samples mounted onto large format conductive glass and conductive plastic MALDI targets, enabling MSI analysis to be performed on both TOF and FT-ICR MALDI mass spectrometers. We show that mounting does not unduly affect small molecule MSI detection by analyzing tiotropium abundance and distribution in rat lung tissues, with direct on-tissue quantitation achieved. Significantly, we use the adhesive tape to provide support to embedded delicate heat-stabilized tissues, enabling sectioning and mounting to be performed that maintained tissue integrity on samples that had previously been impossible to adequately prepare section for MSI analysis. The mapping of larger peptidomic molecules was not hindered by tape mounting samples and we demonstrate this by mapping the distribution of PEP-19 in both native and heat-stabilized rat brains. Furthermore, we show that without heat stabilization PEP-19 degradation fragments can detected and identified directly by MALDI MSI analysis. PMID:22796569

  18. Snap-frozen brain tissue sections stored with desiccant at ambient laboratory conditions without chemical fixation are resistant to degradation for a minimum of 6 months.

    PubMed

    Sadler, Theodore R; Khodavirdi, Ani C; Hinton, David R; Holschneider, Daniel P

    2009-03-01

    Cryosectioned tissues from snap-frozen samples offer the advantage of preserving proteins at the cellular and subcellular levels and maintaining overall cell integrity in the tissue of interest without the use of chemical fixatives. To prevent specific or nonspecific degradation of proteins by autolytic and/or proteolytic processes, it is common practice to immediately store frozen tissue sections obtained from a cryostat under cryogenic conditions, for example -80 degrees C. Our laboratory recently challenged this widely held belief by extracting proteins from brain tissue samples that were archived for 1 day, 1 week, 1 month, and 6 months at various storage conditions (frozen, ambient, or desiccated) without the use of chemical fixatives. Our results from immunofluorescent stains, immunoperoxidase stains, silver stains, and Western blot analyses demonstrated that snap-frozen, heat-dried tissue sections stored and desiccated at ambient laboratory conditions are comparable to frozen samples stored up to 6 months. PMID:19521279

  19. Cardiac Applications of Optogenetics

    PubMed Central

    Ambrosi, Christina M.; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-01-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics. PMID:25035999

  20. The value of immunohistochemistry on paraffin wax embedded tissue sections in the differentiation of small lymphocytic and mantle cell lymphomas.

    PubMed Central

    Singh, N; Wright, D H

    1997-01-01

    AIMS: To determine whether immunohistochemistry applied to paraffin wax embedded biopsy tissue can be used to distinguish between B-small lymphocytic lymphoma (B-SLL) and mantle cell lymphoma (MCL). METHODS: Formalin fixed, paraffin wax embedded tissue blocks of 12 cases of B-SLL and 12 cases of MCL were retrieved from the files of the Department of Pathology, Southampton University Hospitals Trust. Following antigen retrieval, where appropriate, sections were stained for CD3, CD5, CD20, CD23, CD43, Cyclin D, PGP9.5, and MIB1 using a streptavidin-biotin complex technique. RESULTS: CD20 stained the neoplastic cells of B-SLL and MCL, and CD3 labelled the reactive T cells in these tumours. In B-SLL, the T cells were generally dispersed among the tumour cells, whereas in MCL they often formed bands around tumour cell nodules. CD5 could be detected on T cells, following antigen retrieval. The level of expression on B cells of B-SLL and MCL was generally too low to allow detection in paraffin wax embedded tissues. CD23 stained B-SLL but not MCL. However, it could be detected in only five of the 12 cases of B-SLL. CD43 could be detected in most cases of B-SLL and MCL. It is not, therefore, of value in distinguishing between these tumours. It will, however, help in the differentiation of B-SLL and MCL from other low grade B cell lymphomas, such as follicle centre cell and marginal zone lymphomas. Cyclin D was expressed in all of the MCL but in none of the B-SLL. PGP9.5 showed reactivity in most cases of MCL and much weaker reactivity in B-SLL. The proliferation indexes of MCL were generally higher than those of B-SLL, as measured by MIB1 labelling. Both tumours, however, showed a wide range of values and considerable overlap. CONCLUSION: Staining for Cyclin D is the most reliable immunohistochemical mean of differentiating between B-SLL an MCL. High levels of PGP9.5, expressed in MCL, may be related to the degradation of Cyclin D by the ubiquitin pathway. Images PMID

  1. High-sensitivity cardiac troponin T level is associated with angiographic complexity of coronary artery disease: a cross-sectional study.

    PubMed

    Yamazaki, Kenji; Iijima, Raisuke; Nakamura, Masato; Sugi, Kaoru

    2016-06-01

    High levels of high-sensitivity cardiac troponin T (hs-cTnT) are associated with coronary artery disease (CAD). The SYNTAX score (SXscore) is an angiographic tool used to grade the complexity and extent of CAD. We investigated the relationship between hs-cTnT levels and SXscore. We conducted a cross-sectional analysis of 408 patients who underwent first diagnostic coronary angiography between December 2011 and December 2012. SXscore was recorded, and serum hs-cTnT levels were measured in all patients. The median hs-cTnT level was 0.009 μg/L. Elevated hs-cTnT levels (≥0.014 μg/L) were observed in 136 patients (33 %). Twenty-seven patients (7 %) had complex CAD as defined by intermediate or high SXscores. The levels of hs-cTnT were significantly higher in patients with high or intermediate SXscores than in those with low SXscores (0.044 ± 0.055 vs. 0.018 ± 0.058 μg/L, p = 0.03). Multivariate analysis identified hs-cTnT level, and diabetes mellitus as independent predictors for complex CAD. The adjusted odds ratio of hs-cTnT level for predicting complex CAD was 2.86 (95 % confidence interval 1.90-4.45, p < 0.0001). Predictive value of the adjusted area under the receiver operating characteristic curve for complex CAD significantly improved after inclusion of the hs-cTnT (C statistic, 0.882 vs. 0.784). Measurement of serum hs-cTnT level has an important role in the risk stratification of patients who have a plan for diagnostic coronary angiography. In patients with clinically stable angina pectoris, slightly elevated hs-cTnT levels may indicate the presence of complex CAD. PMID:25964074

  2. Analysis of Chloroquine and Metabolites Directly from Whole-body Animal Tissue Sections by Liquid Extraction Surface Analysis (LESA) and Tandem Mass Spectrometry

    SciTech Connect

    Parson, Whitney B; Koeniger, Stormy L; Johnson, Robert W; Erickson, Jamie; Tian, Yu; Stedman, Christopher A.; Schwartz, Annette; Tarcsa, Edit; Cole, Roderic; Van Berkel, Gary J

    2012-01-01

    The rapid and direct analysis of the amount and spatial distribution of exogenous chloroquine and chloroquine metabolites from tissue sections by liquid extraction surface sampling analysis coupled with tandem mass spectrometry (LESA-MS) was demonstrated. LESA-MS results compared well with previously published chloroquine quantification data collected by organ excision, extraction and fluorescent detection. The ability to directly sample and analyze spatially-resolved exogenous molecules from tissue sections with minimal sample preparation and analytical method development has the potential to facilitate the assessment of target tissue penetration of pharmaceutical compounds, to establish pharmacokinetic/pharmacodynamic (PK/PD) relationships, and to complement established pharmacokinetic methods used in the drug discovery process during tissue distribution assessment.

  3. Types of muscle tissue (image)

    MedlinePlus

    The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac muscle cells are located in the walls of the heart, appear striated, and are under involuntary control. Smooth muscle fibers are located in walls of hollow ...

  4. Sudden cardiac arrest in sports - need for uniform registration: A Position Paper from the Sport Cardiology Section of the European Association for Cardiovascular Prevention and Rehabilitation.

    PubMed

    Solberg, E E; Borjesson, M; Sharma, S; Papadakis, M; Wilhelm, M; Drezner, J A; Harmon, K G; Alonso, J M; Heidbuchel, H; Dugmore, D; Panhuyzen-Goedkoop, N M; Mellwig, K-P; Carre, F; Rasmusen, H; Niebauer, J; Behr, E R; Thiene, G; Sheppard, M N; Basso, C; Corrado, D

    2016-04-01

    There are large variations in the incidence, registration methods and reported causes of sudden cardiac arrest/sudden cardiac death (SCA/SCD) in competitive and recreational athletes. A crucial question is to which degree these variations are genuine or partly due to methodological incongruities. This paper discusses the uncertainties about available data and provides comprehensive suggestions for standard definitions and a guide for uniform registration parameters of SCA/SCD. The parameters include a definition of what constitutes an 'athlete', incidence calculations, enrolment of cases, the importance of gender, ethnicity and age of the athlete, as well as the type and level of sporting activity. A precise instruction for autopsy practice in the case of a SCD of athletes is given, including the role of molecular samples and evaluation of possible doping. Rational decisions about cardiac preparticipation screening and cardiac safety at sport facilities requires increased data quality concerning incidence, aetiology and management of SCA/SCD in sports. Uniform standard registration of SCA/SCD in athletes and leisure sportsmen would be a first step towards this goal. PMID:26285770

  5. Dual X-Ray Absorptiometry Whole Body Composition of Bone Tissue in Rheumatoid Arthritis – a Cross-Sectional Study

    PubMed Central

    POPESCU, Claudiu; BOJINCA, Violeta; OPRIS, Daniela; IONESCU, Ruxandra

    2015-01-01

    Objectives: Previous studies of bone tissue in rheumatoid arthritis (RA) using dual X-ray absorptiometry (DXA) concentrated on regions of interest that were used to diagnose osteoporosis. This study aimed to compare the whole body bone tissue (wbBT) of RA patients with healthy subjects and to identify the RA variables which significantly predict wbBT. Methods: The study was cross-sectionally designed to include postmenopausal RA patients and age-matched healthy female controls. All 107 RA patients and all 104 controls underwent clinical examination, laboratory tests and whole body DXA composition, which recorded total and regional bone indices. Non-parametric standard statistical test and regression models after data normalization were used to assess correlations, associations and differences. Results: Compared to controls, RA patients had significantly lower whole body and regional bone mass (14.9 kg compared to 15.5 kg; p = 0.031). Disease duration (r = -0.402 ; p < 0.001), C-reactive protein (r = -0.279; p = 0.015) and inflammation (2.5% wbBT compared to 2.9%; p = 0.043), radiographic damage (14.3 kg compared to 16.2 kg; p < 0.001), disease activity scores (r = -0.275 ; p = 0.018 for HAQ) are significantly correlated/associated with lower wbBT. Clinical structural damage is associated with lower wbBT and it can significantly predict them (R2 = 0.014; p = 0.001), while glucocorticoid treatment, even in low doses, was associated with lower wbBT percent (2.6% compared to 2.8%; p = 0.045). Treatment with biologics was associated with a lower rate of whole body osteoporosis (0% compared to 22.2%; p = 0.013). Conclusions: The main associated factors with the generalized bone loss in female RA patients are disease duration and disease activity. Clinical structural damage is the most powerful predictor of the whole body bone loss. These results suggest a general disturbance of skeletal bone metabolism in RA and could explain a greater risk of fragility fractures of non

  6. A method for preparing 2- to 50-micron-thick fresh-frozen sections of large samples and undecalcified hard tissues.

    PubMed

    Kawamoto, T; Shimizu, M

    2000-05-01

    This article describes a method for preparing 2- to 50-micron-thick fresh-frozen sections from large samples and completely calcified tissue samples. In order to perform the more routine work involved, a tungsten carbide disposable blade was installed to a heavy-duty sledge cryomicrotome. An entire 10-day-old rat and bone and tooth samples from a 7-month-old rat were rapidly frozen. The frozen samples were attached to the cryomicrotome stage. The cutting surface of the samples was covered with a polyvinylidene chloride film coated with synthetic rubber cement and cut at -25 degrees C. The soft tissues and the hard tissues were satisfactorily preserved and all tissue cells were easily identifiable. Enzymatic activity in the fresh sections was much stronger than that in chemically fixed and/or decalcified sections. The sections permitted histological and histochemical studies without trouble. In addition, the sections can be used for multiple experiments such as immunohistochemistry, in situ hybridization, and electron microprobe X-ray micro-analysis. This method can be used with conventional cryomicrotome equipment. PMID:10883392

  7. Comparison between whole mount tissue preparations and virtual tissue microarray samples for measuring Ki-67 and apoptosis indices in human bladder cancer: A cross-sectional study.

    PubMed

    Oshiro, Hisashi; Czerniak, Bogdan A; Sakamaki, Kentaro; Tsuta, Koji; Bondaruk, Jolanta; Keyhani, Afsaneh; Dinney, Colin P; Nagai, Takeshi; Kamat, Ashish M

    2016-08-01

    Recent tissue microarray (TMA)-based studies have shown that cell proliferation- and apoptosis-related biomarkers are associated with clinical outcomes in patients with bladder urothelial carcinoma. However, little is known about the differences in these biomarker measurements between whole mount tissue preparations and TMAs. This study aimed to elucidate the discrepancy in the measurements of Ki-67 indices (KIs) and apoptosis indices (AIs) between whole mount tissue preparations and TMAs of bladder urothelial carcinoma samples.Whole mount tissue preparations for Ki-67 immunohistochemistry and terminal deoxynucleotidyl transferase dUTP nick end labeling were made from 30 patients who underwent transurethral resection of bladder urothelial carcinoma. Digital microscopy-assisted virtual TMAs, consisting of 3 small round areas (1 or 0.6 mm in diameter), were generated from the same whole mount tissue preparations. The measurement results in highly reactive areas of biomarkers were compared between the whole mount tissue preparation- and the TMA-based methods. Bland-Altman plot analysis, regression analysis, and Kendall τ were performed to investigate differences in the measurement results, systematic biases, and correlations between biomarkers.Although the Bland-Altman plot analysis demonstrated that almost all the plots were within the limits of agreement, fixed biases were detected in the 1- and 0.6-mm TMAs for the KI (0.181 and 0.222, respectively) and the AI (0.055 and 0.063, respectively). Proportional biases were also detected in the 1- and 0.6-mm TMAs for the AI (P < 0.001 and P < 0.001, respectively). Furthermore, positive correlations between KIs and AIs were observed in whole mount tissue preparations (r = 0.260, P = 0.044) and in the 1 mm TMAs (r = 0.375, P = 0.004); however, no such correlation was observed in the 0.6 mm TMAs.Our study suggests that the measurement results for certain biomarkers of bladder urothelial

  8. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Hernandez-Moya, Sonia

    2009-01-01

    NASA seeks to transfer the NASA developed microwave ablation technology, designed for the treatment of ventricular tachycardia (irregular heart beat), to industry. After a heart attack, many cells surrounding the resulting scar continue to live but are abnormal electrically; they may conduct impulses unusually slowly or fire when they would typically be silent. These diseased areas might disturb smooth signaling by forming a reentrant circuit in the muscle. The objective of microwave ablation is to heat and kill these diseased cells to restore appropriate electrical activity in the heart. This technology is a method and apparatus that provides for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In comparison with other methods that involve direct-current pulses or radio frequencies below 1 GHz, this method may prove more effective in treating ventricular tachycardia. This is because the present method provides for greater control of the location, cross-sectional area, and depth of a lesion via selection of the location and design of the antenna and the choice of microwave power and frequency.

  9. Mapping cardiac surface mechanics with structured light imaging

    PubMed Central

    Laughner, Jacob I.; Zhang, Song; Li, Hao; Shao, Connie C.

    2012-01-01

    Cardiovascular disease often manifests as a combination of pathological electrical and structural heart remodeling. The relationship between mechanics and electrophysiology is crucial to our understanding of mechanisms of cardiac arrhythmias and the treatment of cardiac disease. While several technologies exist for describing whole heart electrophysiology, studies of cardiac mechanics are often limited to rhythmic patterns or small sections of tissue. Here, we present a comprehensive system based on ultrafast three-dimensional (3-D) structured light imaging to map surface dynamics of whole heart cardiac motion. Additionally, we introduce a novel nonrigid motion-tracking algorithm based on an isometry-maximizing optimization framework that forms correspondences between consecutive 3-D frames without the use of any fiducial markers. By combining our 3-D imaging system with nonrigid surface registration, we are able to measure cardiac surface mechanics at unprecedented spatial and temporal resolution. In conclusion, we demonstrate accurate cardiac deformation at over 200,000 surface points of a rabbit heart recorded at 200 frames/s and validate our results on highly contrasting heart motions during normal sinus rhythm, ventricular pacing, and ventricular fibrillation. PMID:22796539

  10. Mechanisms of cardiac arrhythmias

    PubMed Central

    Tse, Gary

    2015-01-01

    Blood circulation is the result of the beating of the heart, which provides the mechanical force to pump oxygenated blood to, and deoxygenated blood away from, the peripheral tissues. This depends critically on the preceding electrical activation. Disruptions in the orderly pattern of this propagating cardiac excitation wave can lead to arrhythmias. Understanding of the mechanisms underlying their generation and maintenance requires knowledge of the ionic contributions to the cardiac action potential, which is discussed in the first part of this review. A brief outline of the different classification systems for arrhythmogenesis is then provided, followed by a detailed discussion for each mechanism in turn, highlighting recent advances in this area. PMID:27092186

  11. Reference values of myocardial structure, function, and tissue composition by cardiac magnetic resonance in healthy African-Americans at 3T and their relations to serologic and cardiovascular risk factors.

    PubMed

    Liu, Chia-Ying; Bluemke, David A; Gerstenblith, Gary; Zimmerman, Stefan L; Li, Ji; Zhu, Hong; Lai, Shenghan; Lai, Hong

    2014-09-01

    Cardiac magnetic resonance (CMR) is a standard of reference for cardiac structure and function. Recent advances in T1 mapping and spectroscopy also provide assessment of myocardial tissue composition. However, the reference ranges of left ventricular parameters have rarely been assessed in an African-American (AA) population without known cardiac disease. To estimate the reference values of myocardial structure, function, and tissue composition by CMR and to explore their relationships to serologic factors and cardiovascular risk factors in asymptomatic AAs with low Framingham risk, between November 2010 and June 2012, 92 healthy AAs aged ≥21 years, from Baltimore, MD, were enrolled in an observational study. CMR examination was performed on a 3T scanner. Proton magnetic resonance spectroscopy was performed to noninvasively quantify myocardial triglyceride content. Native T1 values were obtained from modified Look-Locker inversion recovery sequence. The median age was 37 (interquartile range IQR 27 to 44) years (41% men). The median native T1 time of the myocardium was 1,228 ms (IQR 1,200 to 1,263) with no gender difference. The median myocardial fat content was 0.6% (IQR 0.7% to 4.6%). Native T1 time was not influenced by age, sex, and body mass index. Among the factors investigated, myocardial fat and elevated C-reactive protein (>2.0 mg/dL) were independently associated with T1 relaxation time. Native T1 time was also independently associated with left ventricular end-diastolic volume indexed to body surface area. In conclusion, this study of asymptomatic AAs provides reference ranges for cardiovascular structure, function, and tissue composition. Alterations in myocardial fat are associated with native T1 time, a CMR measure of interstitial fibrosis. PMID:25037675

  12. Comparison of Drug Distribution Images from Thin Tissue Sections Obtained Using Desorption Electrospray Ionization Tandem Mass Spectrometry and Whole-Body Autoradiography

    SciTech Connect

    Kertesz, Vilmos; Van Berkel, Gary J; Vavek, Marissa; Koeplinger, Kenneth A.; Schneider, Bradley B; Covey, Thomas R.

    2008-01-01

    Desorption electrospray ionization tandem mass spectrometry (DESI-MS/MS) and whole-body autoradiography (WBA) were used for chemical imaging of whole-body thin tissue sections of mice intravenously dosed with propranolol (7.5 mg/kg). DESI-MS/MS imaging utilized selected reaction monitoring detection performed on an AB/MDS SCIEX 4000 QTRAP mass spectrometer equipped with a prototype extended length particle discriminator interface. Propranolol images of the tissue sections using DESI-MS/MS were obtained at surface scan rates of 0.1, 0.5, 2 and 7 mm/s. Although signal decreased with increasing scan rate, useful whole-body images for propranolol were obtained from the tissues even at 7 mm/s, which required just 79 min of analysis time. Attempts to detect and image the distribution of the known propranolol metabolites were unsuccessful. Regions of the tissue sections showing the most radioactivity from WBA sections were excised and analyzed by HPLC with radiochemical detection to determine relative levels of propranolol and metabolites present. Comparison of the DESI-MS/MS signal for propranolol and the radioactivity attributed to propranolol from WBA sections indicated nominal agreement between the two techniques for the amount of propranolol in the brain, lung, and liver. Data from the kidney showed an unexplained disparity between the two techniques. The results of this study show the feasibility of using DESI-MS/MS to obtain useful chemical images of a drug in whole-body thin tissue sections following drug administration at a pharmacologically relevant level. Further optimization to improve sensitivity and enable detection of the drug metabolites will be among the requirements necessary to move DESI-MS/MS chemical imaging forward as a practical tool in drug discovery.

  13. Use of softening agents to improve the production of formalin-fixed, paraffin-embedded sections of nail tissue: an assessment.

    PubMed

    Orchard, G E; Torres, J; Sounthararajah, R

    2008-01-01

    The use of tissue softeners to enhance the quality of tissue sections of heavily keratotic tissue is not widely published. There are very few indicators in the scientific literature that attempt to compare and contrast the benefits and disadvantages of such techniques, as most are passed down through word of mouth rather than through published data. This study attempts to present a preliminary evaluation of several methods employing tissue softeners to facilitate the preparation of reproducible, good-quality formalin-fixed, paraffin-embedded sections of nail tissue. A standard 10-minute surface application of each softener is employed for all paraffin-embedded tissue in order to ensure consistency. The results show that the use of Veet (hair remover), Fairy Liquid or fabric conditioner provides the most beneficial results. Thus, widely available products can be used in preference to specific commercially produced reagents that have no clear benefits and can cost considerably more to purchase. This study will form the basis of a more in-depth evaluation of the most beneficial softeners, in an attempt to determine optimal parameters for their use in routine histopathology laboratories. PMID:19055107

  14. Current perspectives on cardiac amyloidosis

    PubMed Central

    Guan, Jian; Mishra, Shikha; Falk, Rodney H.

    2012-01-01

    Amyloidosis represents a group of diseases in which proteins undergo misfolding to form insoluble fibrils with subsequent tissue deposition. While almost all deposited amyloid fibers share a common nonbranched morphology, the affected end organs, clinical presentation, treatment strategies, and prognosis vary greatly among this group of diseases and are largely dependent on the specific amyloid precursor protein. To date, at least 27 precursor proteins have been identified to result in either local tissue or systemic amyloidosis, with nine of them manifesting in cardiac deposition and resulting in a syndrome termed “cardiac amyloidosis” or “amyloid cardiomyopathy.” Although cardiac amyloidosis has been traditionally considered to be a rare disorder, as clinical appreciation and understanding continues to grow, so too has the prevalence, suggesting that this disease may be greatly underdiagnosed. The most common form of cardiac amyloidosis is associated with circulating amyloidogenic monoclonal immunoglobulin light chain proteins. Other major cardiac amyloidoses result from a misfolding of products of mutated or wild-type transthyretin protein. While the various cardiac amyloidoses share a common functional consequence, namely, an infiltrative cardiomyopathy with restrictive pathophysiology leading to progressive heart failure, the underlying pathophysiology and clinical syndrome varies with each precursor protein. Herein, we aim to provide an up-to-date overview of cardiac amyloidosis from nomenclature to molecular mechanisms and treatment options, with a particular focus on amyloidogenic immunoglobulin light chain protein cardiac amyloidosis. PMID:22058156

  15. Application of a Liquid Extraction Based Sealing Surface Sampling Probe for Mass Spectrometric Analysis of Dried Blood Spots and Mouse Whole-Body Thin Tissue Sections

    SciTech Connect

    Van Berkel, Gary J; Kertesz, Vilmos

    2009-01-01

    The utility of a liquid extraction based sealing surface sampling probe (SSSP) for the direct mass spectrometric analysis of targeted drugs and metabolites in dried blood spots (DBSs) and whole mouse thin tissue sections was demonstrated. The accuracy and precision for the quantitative analysis of a minimum of 50 ng/mL sitamaquine or acetaminophen in DBSs on paper were well within the required 15% dictated by internationally recognized acceptance criteria for assay validations. Analysis of whole-body mouse thin tissue sections from animals dosed with propranolol, adhered to an adhesive tape substrate, provided semi-quantitative information for propranolol and its hydroxyproranolol glucuronide metabolite within specific organs of the tissue. The relative abundances recorded for the two compounds in the brain, lung, kidney and liver were in nominal agreement with previously reported amounts based on analysis using a liquid microjunction surface sampling probe (LMJ-SSP), and whole-body autoradiography (WBA) and HPLC-MS analysis. The ability to sample and analyze from tape-adhered tissue samples, which are generally employed in WBA analysis, presents the possibility of consecutive WBA and SSSP-MS analysis of the same tissue section. This would facilitate assignment, and possibly quantitation, of the different molecular forms of total drug related material detected in the WBA analysis. The flexibility to sample larger or smaller spot sizes, alternative probe sealing mechanisms, and a reduction in internal volumes and associated sample carryover issues will be among the first simple improvements necessary to make the SSSP-MS method a practical DBS and/or thin tissue section analysis tool or to expand its use to other surface sampling applications.

  16. Cardiac toxicities of antibiotics.

    PubMed Central

    Adams, H R; Parker, J L; Durrett, L R

    1978-01-01

    Isolated heart muscle preparations are useful in the study of cardiac toxicities of drugs and environmental chemicals: such tissues allow assessment of chemical effects on heart muscle that is free from indirect in vivo influences that can mask or even accentuate cardiac responses measured in the intact animal. In the present study, left atria of guinea pigs were used to demonstrate a direct cardiac depressant effect of greater-than-therapeutic concentrations of several aminoglycoside antibiotics. The toxic effect of these antibiotics seems to be a calcium-dependent event, and may prove useful to characterize contractile responses of the heart. Other antibiotic agents can also depress cardiovascular function, as summarized in this report, but mechanisms of action have not been clearly defined. PMID:720315