Posts in Category: Heart Failure & Cardiac Disease

Noninvasive Imaging in Adult Congenital Heart Disease

Noninvasive Imaging in Adult Congenital Heart Disease

Luke J. Burchill, Jennifer Huang, Justin T. Tretter, Abigail M. Khan, Andrew M. Crean, Gruschen R. Veldtman, Sanjiv Kaul, Craig S. Broberg

Three-dimensional (3D) echocardiographic quantification. In this example, left atrial and left ventricular volumes are measured using semiautomated border detection in a 3D echocardiogram. Ejection fraction can be derived without the geometric assumptions that limited 2D-derived measures, such as Simpson biplane and the area–length method. [Powerpoint File]

Noninvasive Imaging in Adult Congenital Heart Disease

Noninvasive Imaging in Adult Congenital Heart Disease

Luke J. Burchill, Jennifer Huang, Justin T. Tretter, Abigail M. Khan, Andrew M. Crean, Gruschen R. Veldtman, Sanjiv Kaul, Craig S. Broberg

Liver imaging in Fontan-associated liver disease. A, Contrast computed tomographic scan of upper abdomen in a patient with heterotaxy and a Fontan circulation demonstrating a well-circumscribed tumor measuring 5 cm in diameter in the right lobe of a midline liver (yellow asterix). B, Fluorodeoxyglucose-positron emission tomographic scan in the same patient demonstrating abnormal uptake in the right lobe of the liver in the region of the tumor. [Powerpoint File]

Current Interventional and Surgical Management of Congenital Heart Disease: Specific Focus on Valvular Disease and Cardiac Arrhythmias

Current Interventional and Surgical Management of Congenital Heart Disease: Specific Focus on Valvular Disease and Cardiac Arrhythmias

Kimberly A. Holst, Sameh M. Said, Timothy J. Nelson, Bryan C. Cannon, Joseph A. Dearani

Schematic representation of the possible lines of ablation to treat macro reentrant atrial tachycardia in the presence of various atrial anomalies associated with complex congenital heart disease. avn indicates atrioventricular node; CS, coronary sinus; FO, foramen ovale; HV, hepatic vein; IVC, inferior vena cava; LAA, left atrial appendage; LSVC, left superior vena cava; MV, mitral valve; PV, pulmonary valve; RAA, right atrial appendage; RSVC, right superior vena cava; TAPVR, total anomalous pulmonary venous return; and TV, tricuspid valve. Reproduced from Mavroudis et al53 with permission of the publisher. Copyright ©2008, The Society of Thoracic Surgeons. [Powerpoint File]

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Thomas Doetschman, Teodora Georgieva

Large deletions, marker insertions, and single-nucleotide polymorphism (SNP) insertions. A, Multiple exons can be deleted by nonhomologous end joining (NHEJ) by designing single-guide RNAs (sgRNAs) that flank the region to be deleted. In the presence of Cas9 double-strand DNA breaks (DSBs) will occur resulting in small indels at the site of end joining. The double bar at the sgRNA:gene hybridization site represents the DSB caused by Cas9. Cas9 can be introduced as either mRNA or recombinant protein. B, Marker gene insertion can be achieved through homology-directed repair (HDR) in which the homologous regions are introduced in a plasmid as would be done by gene targeting. C, A chromosomal region deletion has been done using HDR in which 2 sgRNAs were designed at each end of the region to be deleted. The homology template was an single-strand DNA (ssDNA) oligo with homology at each end of the region to be deleted. D, SNP insertion using HDR with ssDNA oligo as homology template. [Powerpoint File]

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Thomas Doetschman, Teodora Georgieva

Cas9 RNA-guided nuclease system. Schematic representation of the Streptococcus pyogenes Cas9 nuclease (green) targeted to genomic DNA by a single-guide RNA (sgRNA) consisting of an ≈20-nt guide sequence (blue) and a scaffold (red). The guide sequence is directly upstream of the protospacer adjacent motif (PAM), NGG (orange circles). Cas9 mediates a double-strand DNA break (DSB) ≈3 bp upstream of the PAM (red triangles). The break is repaired by 1 of 2 mechanisms: nonhomologous end joining (NHEJ) that creates random insertions or deletions at the target site or homology-directed repair (HDR). Two types of template can be used for HDR: small single-stranded DNA (ssDNA) oligonucleotide donor with short 60- 70-bp homology arms and a linear or circular dsDNA plasmid with long homology arms of 1 to 3 kb. [Powerpoint File]

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Thomas Doetschman, Teodora Georgieva

High-throughput screens. A, High-throughput gene knockout screens in which a lentiviral single-guide RNA (sgRNA) library for multiple sites in the early coding region of thousands of genes results in cell clones in which each single gene is knocked out by nonhomologous end joining repair in which indels occur. Several clones will represent each gene. A screen for a specific phenotypic outcome, such as drug resistance or altered growth, will identify genes involved in those processes. B, High-throughput screen for long noncoding RNAs (lncRNAs). A lentiviral library of paired sgRNAs, each pair of which flanks an individual lncRNA, is transduced into cells along with Cas9. Several sgRNA pairs (color matched) are designed for each lncRNA. Phenotyping clones with similar characteristics will identify lncRNAs associated with that phenotype. C, High-throughput regulatory region screen. A lentiviral library consisting of sgRNAs for tiling at ≈10-bp intervals in the regulatory region of multiple genes can be used to identify regulatory regions for each gene. A similar approach has been used to make a library of cells in which a guide RNA (gRNA or CRISPR RNA) is inserted into a modified Rosa locus in which the hairpin RNA (or tracrRNA) is adjacent to the gRNA insertion site thereby generating a sgRNA for each cell. ssDNA indicates single-strand DNA. [Powerpoint File]

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Thomas Doetschman, Teodora Georgieva

CRISPR-mediated modulation of gene expression. A, CRISPR interference system with dCas9 (dead, nuclease-deficient Cas9 colored in red) fused to the negative transcriptional effector KRAB (Krüppel-associated box of the Kox1 gene, colored red). A lentiviral library of single-guide RNAs for tiling at gene regulatory regions can identify enhancer elements and their location flanking the transcriptional start site (TSS) that affect gene expression. B, CRISPR activation system with dCas9 fused to a tethered string of an antibody epitope. Cotransduction of an epitope-specific antibody fused to multiple Herpes virus transcriptional activation genes VP16 will bind to the string of epitopes bringing multiple VP16s to the transcriptional machinery, thereby activating the gene. VP64 is a complex of 4 VP16 molecules. Figure derived from Figure 5A from Tanenbaum et al. [Powerpoint File]

Novel Risk Markers and Risk Assessments for Cardiovascular Disease

Novel Risk Markers and Risk Assessments for Cardiovascular Disease

Mark R. Thomas, Gregory Y.H. Lip

Acute coronary syndromes. A, Foam cells (derived from macrophages [Ma]) and lymphocytes have a central role in the development of a lipid-rich atherosclerotic plaque with a necrotic core (NC). Rupture or erosion of an atherosclerotic plaque triggers platelet (P) adhesion to subendothelial components, resulting in the formation of an occlusive thrombus, which also recruits monocytes (M) and neutrophils (N). Platelet–leukocyte interactions cause the release of proinflammatory cytokines and recruited neutrophils also release neutrophil extracellular traps. B, Myocardial ischemia, caused by coronary artery obstruction, leads to the recruitment of neutrophils and monocytes toward chemokines. Leukocyte adhesion molecules then mediate transmigration of leukocytes. Monocytes may then differentiate into Ma, alongside Ma that are already resident within myocardial tissue. Fibroblasts (F) proliferate and differentiate into myofibroblasts (MF). C, Impaired myocardial contractility and hemodynamics results in myocardial stretch, leading to consequent renal disturbances. [Powerpoint File]

Novel Risk Markers and Risk Assessments for Cardiovascular Disease

Novel Risk Markers and Risk Assessments for Cardiovascular Disease

Mark R. Thomas, Gregory Y.H. Lip

Heart failure. A, Myocardial injury, which may be triggered by a variety of insults, can lead to (B) myocardial necrosis, systemic inflammation, and infiltration of leukocytes, predominantly neutrophils (N), driven by chemokines and cytokines. N release their granule contents, thereby exerting oxidative stress and phagocytose necrotic cells and dead cardiomyocytes (DC) in conjunction with activated macrophages (Ma). C, A subsequent transition toward a reparative phase involves downregulation of the inflammatory response, release of anti-inflammatory cytokines, such as interleukin-10, and proliferation of monocytes (Mo) and lymphocytes (L). Fibroblasts (F) proliferate and differentiate in to myofibroblasts (MF), which promote collagen production and fibrosis, mediated in particular by transforming growth factor-β. D, The subsequent formation of a collagen (C)-rich scar maintains structural integrity of the myocardium at the expense of contractility and electric conductivity. [Powerpoint File]

Novel Risk Markers and Risk Assessments for Cardiovascular Disease

Novel Risk Markers and Risk Assessments for Cardiovascular Disease

Mark R. Thomas, Gregory Y.H. Lip

Atrial fibrillation (AF). The pathophysiology of AF is complex. Atrial fibrosis and electric abnormalities, including abnormal calcium homeostasis and ion-channel dysfunction, play a particularly prominent role in precipitating AF, whereas inflammation and oxidative stress reinforce pathological changes in myocardial structure. After the onset of AF, reduced blood flow through the atria predisposes toward thrombosis. The formation of an atrial thrombus, with subsequent embolization to the brain, is one of the most important causes of stroke, which may have devastating consequences. It is well-recognized that thrombosis may not purely be related to stasis of blood within the atria, but likely also reflects multiple clinical risk factors for stroke, which are particularly common in patients with AF. [Powerpoint File]

Purinergic Signaling in the Cardiovascular System

Purinergic Signaling in the Cardiovascular System

Geoffrey Burnstock

Central vagal cardiocardiac reflex triggered by ATP.230 Illustration Credit: Ben Smith. [Powerpoint File]

Purinergic Signaling in the Cardiovascular System

Purinergic Signaling in the Cardiovascular System

Geoffrey Burnstock

Three P2 receptor subtypes, P2X1, P2Y1, and P2Y12, are involved in ADP-induced platelet activation. Clopidogrel is a P2Y12 receptor blocker that inhibits platelet aggregation and is in highly successful use for the treatment of thrombosis and stroke. A P2Y1 receptor antagonist, MRS 2500, inhibits shape change.234 Illustration Credit: Ben Smith. [Powerpoint FIle]

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

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

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

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

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

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

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

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

Advances in Echocardiographic Imaging in Heart Failure With Reduced and Preserved Ejection Fraction

Advances in Echocardiographic Imaging in Heart Failure With Reduced and Preserved Ejection Fraction

Alaa Mabrouk Salem Omar, Manish Bansal, Partho P. Sengupta

Myocardial mechanical dysfunction in heart failure. Subendocardial dysfunction attenuates left ventricular (LV) longitudinal function; this may be compensated by hypernormal or relatively preserved mechanical function in other directions. Progressive insult with transmural affection causes exhaustion of the compensatory mechanisms and development of dilated myocardial chambers and reduction of ejection fraction (EF). In the rare occasion of subepicardial dysfunction, for example in pericardial disease, longitudinal function may remain relatively preserved, whereas myocardial functions in circumferential direction are more affected (reduced circumferential shortening and torsion). [Powerpoint File]