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PURPOSE OF REVIEW - Cancer therapeutics have seen tremendous growth in the last decade and have been effective in the treatment of several cancer types. However, with advanced therapies like kinase inhibitors and immunotherapies, there have been unintended consequences of cardiotoxicities. While traditional chemotherapy and radiation-induced cardiotoxicity have been well studied, further research is needed to understand the adverse effects of newer regimens.
RECENT FINDINGS - Both immune-mediated and non-immune-medicated cytotoxicity have been noted with targeted therapies such as tyrosine kinase inhibitors and immune checkpoint inhibitors. In this manuscript, we describe the pericardial syndromes associated with cancer therapies and propose management strategies. Pericardial effusion and pericarditis are common presentations in cancer patients and often difficult to diagnose. Concomitant myocarditis may also present with pericardial toxicity, especially with immunotherapies. In addition to proper history and physical, additional testing such as cardiovascular imaging and tissue histology need to be obtained as appropriate. Holding the offending oncology drug, and institution of anti-inflammatory medications, and immunosuppressants such as steroids are indicated. A high index of suspicion, use of standardized definitions, and comprehensive evaluation are needed for early identification, appropriate treatment, and better outcomes for patients with cancer treatment-associated pericardial disease. Further research is needed to understand the pathophysiology and to evaluate how the management of pericardial conditions in these patients differ from traditional management and also evaluate new therapies.
Acute myocardial infarction (MI) provokes an inflammatory response in the heart that removes damaged tissues to facilitate tissue repair/regeneration. However, overactive and prolonged inflammation compromises healing, which may be counteracted by antiinflammatory mechanisms. A key regulatory factor in an inflammatory response is the antiinflammatory cytokine IL-10, which can be produced by a number of immune cells, including subsets of B lymphocytes. Here, we investigated IL-10-producing B cells in pericardial adipose tissues (PATs) and their role in the healing process following acute MI in mice. We found that IL-10-producing B cells were enriched in PATs compared to other adipose depots throughout the body, with the majority of them bearing a surface phenotype consistent with CD5 B-1a cells (CD5 B cells). These cells were detected early in life, maintained a steady presence during adulthood, and resided in fat-associated lymphoid clusters. The cytokine IL-33 and the chemokine CXCL13 were preferentially expressed in PATs and contributed to the enrichment of IL-10-producing CD5 B cells. Following acute MI, the pool of CD5 B cells was expanded in PATs. These cells accumulated in the infarcted heart during the resolution of MI-induced inflammation. B cell-specific deletion of IL-10 worsened cardiac function, exacerbated myocardial injury, and delayed resolution of inflammation following acute MI. These results revealed enrichment of IL-10-producing B cells in PATs and a significant contribution of these cells to the antiinflammatory processes that terminate MI-induced inflammation. Together, these findings have identified IL-10-producing B cells as therapeutic targets to improve the outcome of MI.
Genetic mutations in the human small heat shock protein αB-crystallin have been implicated in autosomal cataracts and skeletal myopathies, including heart muscle diseases (cardiomyopathy). Although these mutations lead to modulation of their chaperone activity , the functions of αB-crystallin in the maintenance of both lens transparency and muscle integrity remain unclear. This lack of information has hindered a mechanistic understanding of these diseases. To better define the functional roles of αB-crystallin, we generated loss-of-function zebrafish mutant lines by utilizing the CRISPR/Cas9 system to specifically disrupt the two αB-crystallin genes, α and α We observed lens abnormalities in the mutant lines of both genes, and the penetrance of the lens phenotype was higher in α than α mutants. This finding is in contrast with the lack of a phenotype previously reported in αB-crystallin knock-out mice and suggests that the elevated chaperone activity of the two zebrafish orthologs is critical for lens development. Besides its key role in the lens, we uncovered another critical role for αB-crystallin in providing stress tolerance to the heart. The αB-crystallin mutants exhibited hypersusceptibility to develop pericardial edema when challenged by crowding stress or exposed to elevated cortisol stress, both of which activate glucocorticoid receptor signaling. Our work illuminates the involvement of αB-crystallin in stress tolerance of the heart presumably through the proteostasis network and reinforces the critical role of the chaperone activity of αB-crystallin in the maintenance of lens transparency.
© 2018 by The American Society for Biochemistry and Molecular Biology, Inc.
OBJECTIVE - Excess deposition of fat within and around vital organs and nonadipose tissues is hypothesized to contribute to cardiovascular disease (CVD) risk. We evaluated the association of abdominal intermuscular adipose tissue (IMAT) volume with coronary artery calcification in the CARDIA study (Coronary Artery Risk Development in Young Adults) participants.
APPROACH AND RESULTS - We measured IMAT in the abdominal muscles, visceral adipose tissue and pericardial adipose tissue, and coronary artery calcification using computed tomography in 3051 CARDIA participants (56% women) at the CARDIA year 25 examination (2010-2011). Mean IMAT volume and mean IMAT/total muscle volume (IMAT normalized for muscle size) were calculated in a 10-mm block of slices centered at L3-L4. Multivariable analyses included potential confounders and traditional cardiovascular disease risk factors. Compared with the lowest quartile, the upper quartile of abdominal IMAT volume was associated with higher coronary artery calcification prevalence (odds ratio [95% confidence interval], 1.6 [1.2-2.1]) after adjusting for cardiovascular disease risk factors. Results were similar for highest versus lowest quartile of IMAT normalized to total muscle volume (odds ratio [95% confidence interval], 1.5 [1.1-2.0]). Significant associations of higher IMAT and normalized IMAT with coronary artery calcification prevalence persisted when body mass index, visceral adipose tissue, or pericardial adipose tissue were added to the models.
CONCLUSIONS - In a large, community-based, cross-sectional study, we found that higher abdominal skeletal muscle adipose tissue volume was associated with subclinical atherosclerosis independent of traditional cardiovascular disease risk factors and other adipose depots.
© 2017 American Heart Association, Inc.
Epithelial-Mesenchymal Transformation (EMT) and the subsequent invasion of epicardial and endocardial cells during cardiac development is critical to the development of the coronary vessels and heart valves. The transformed cells give rise to cardiac fibroblasts and vascular smooth muscle cells or valvular interstitial cells, respectively. The Type III Transforming Growth Factor β (TGFβR3) receptor regulates EMT and cell invasion in both cell types, but the signaling mechanisms downstream of TGFβR3 are not well understood. Here we use epicardial and endocardial cells in in vitro cell invasion assays to identify common mechanisms downstream of TGFβR3 that regulate cell invasion. Inhibition of NF-κB activity blocked cell invasion in epicardial and endocardial cells. NF-κB signaling was found to be dysregulated in Tgfbr3(-/-) epicardial cells which also show impaired cell invasion in response to ligand. TGFβR3-dependent cell invasion is also dependent upon Activin Receptor-Like Kinase (ALK) 2, ALK3, and ALK5 activity. A TGFβR3 mutant that contains a threonine to alanine substitution at residue 841 (TGFβR3-T841A) induces ligand-independent cell invasion in both epicardial and endocardial cells in vitro. These findings reveal a role for NF-κB signaling in the regulation of epicardial and endocardial cell invasion and identify a mutation in TGFβR3 which stimulates ligand-independent signaling.
Copyright © 2016 Elsevier Inc. All rights reserved.
BACKGROUND AND AIMS - Pericardial adipose tissue (PAT) is located on both sides of the pericardium. We tested whether PAT was associated with prevalent diabetes at the year 25 exam of the Coronary Artery Risk Development in Young Adults (CARDIA) study.
METHODS AND RESULTS - The CARDIA Year 25 exam (2010-2011) included complete data for all covariates on 3107 participants. Prevalent diabetes (n = 436) was defined as high fasting (≥126 mg/dl) or 2-h postload glucose (≥200 mg/dl) or HbA1c (≥6.5%) or use of diabetes medications. Volume of PAT was measured from computed tomographic scans. Logistic regression was performed to examine the relationship between quartiles of PAT and diabetes. In regression models adjusted for field center, sex, race, age, systolic blood pressure, total cholesterol, log triglycerides, and treatment with blood pressure and cholesterol lowering medication, PAT volume in the 4th quartile was significantly associated with diabetes status after adjustment for BMI (OR 2.57, 95% CI 1.66, 3.98) or visceral adipose tissue (OR 2.08, 95% CI 1.32, 3.29). PAT volume in the 2nd and 3rd quartiles was not significantly associated with diabetes status relative to the first quartile.
CONCLUSIONS - Metabolically active pericardial adipose tissue is associated with prevalent diabetes only at higher volumes independent of overall obesity.
Copyright © 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.
BACKGROUND - The relationship between epicardial and body surface potentials defines the forward problem of electrocardiography. A robust formulation of the forward problem is instrumental to solving the inverse problem, in which epicardial potentials are computed from known body surface potentials. Here, the accuracy of different forward models has been evaluated experimentally.
METHODS AND RESULTS - Body surface and epicardial potentials were recorded simultaneously in anesthetized closed-chest pigs (n=5) during sinus rhythm, and epicardial and endocardial ventricular pacing (65 records in total). Body surface potentials were simulated from epicardial recordings using experiment-specific volume conductor models constructed from magnetic resonance imaging. Results for homogeneous (isotropic electric properties) and inhomogeneous (incorporating lungs, anisotropic skeletal muscle, and subcutaneous fat) forward models were compared with measured body surface potentials. Correlation coefficients were 0.85±0.08 across all animals and activation sequences with no significant difference between homogeneous and inhomogeneous solutions (P=0.85). Despite this, there was considerable variance between simulated and measured body surface potential distributions. Differences between the body surface potential extrema predicted with homogeneous forward models were 55% to 78% greater than observed (P<0.05) and attenuation of potentials adjacent to extrema were 10% to 171% greater (P<0.03). The length and orientation of the vector between potential extrema were also significantly different. Inclusion of inhomogeneous electric properties in the forward model reduced, but did not eliminate these differences.
CONCLUSIONS - These results demonstrate that homogeneous volume conductor models introduce substantial spatial inaccuracies in forward problem solutions. This probably affects the precision of inverse reconstructions of cardiac potentials, in which this assumption is made.
© 2015 American Heart Association, Inc.
During embryogenesis, the epicardium undergoes proliferation, migration, and differentiation into several cardiac cell types which contribute to the coronary vessels. This process requires epithelial to mesenchymal transition (EMT) and directed cellular invasion. The Type III Transforming Growth Factor-beta Receptor (TGFβR3) is required for epicardial cell invasion and coronary vessel development. Using primary epicardial cells derived from Tgfbr3(+/+) and Tgfbr3(-/-) mouse embryos, high-molecular weight hyaluronan (HMWHA) stimulated cellular invasion and filamentous (f-actin) polymerization are detected in Tgfbr3(+/+) cells, but not in Tgfbr3(-/-) cells. Furthermore, HMWHA-stimulated cellular invasion and f-actin polymerization in Tgfbr3(+/+) epicardial cells are dependent on Src kinase. Src activation in HMWHA-stimulated Tgfbr3(-/-) epicardial cells is not detected in response to HMWHA. RhoA and Rac1 also fail to activate in response to HMWHA in Tgfbr3(-/-) cells. These events coincide with defective f-actin formation and deficient cellular invasion. Finally, a T841A activating substitution in TGFβR3 drives ligand-independent Src activation. Collectively, these data define a TGFβR3-Src-RhoA/Rac1 pathway that is essential for hyaluronan-directed cell invasion in epicardial cells.
Copyright © 2015 Elsevier Inc. All rights reserved.
Arsenic exposure during embryonic development can cause ischemic heart pathologies later in adulthood which may originate from impairment in proper blood vessel formation. The arsenic-associated detrimental effects are mediated by arsenite (iAs(III)) and its most toxic metabolite, monomethylarsonous acid [MMA (III)]. The impact of MMA (III) on coronary artery development has not yet been studied. The key cellular process that regulates coronary vessel development is the epithelial-mesenchymal transition (EMT). During cardiac EMT, activated epicardial progenitor cells transform to mesenchymal cells to form the cellular components of coronary vessels. Smad2/3 mediated TGFβ2 signaling, the key regulator of cardiac EMT, is disrupted by arsenite exposure. In this study, we compared the cardiac toxicity of MMA (III) with arsenite. Epicardial progenitor cells are 15 times more sensitive to MMA (III) cytotoxicity when compared with arsenite. MMA (III) caused a significant blockage in epicardial cellular transformation and invasion at doses 10 times lower than arsenite. Key EMT genes including TGFβ ligands, TβRIII, Has2, CD44, Snail1, TBX18, and MMP2 were down regulated by MMA (III) exposure. MMA (III) disrupted Smad2/3 activation at a dose 20 times lower than arsenite. Both arsenite and MMA (III) significantly inhibited Erk1/2 and Erk5 phosphorylation. Nuclear translocation of Smad2/3 and Erk5 was also blocked by arsenical exposure. However, p38 activation, as well as smooth muscle differentiation, was refractory to the inhibition by the arsenicals. Collectively, these findings revealed that MMA (III) is a selective disruptor of cardiac EMT and as such may predispose to arsenic-associated cardiovascular disorders.
© The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: email@example.com.
Directional cell movement is universally required for tissue morphogenesis. Although it is known that cell/matrix interactions are essential for directional movement in heart development, the mechanisms governing these interactions require elucidation. Here we demonstrate that a novel protein/protein interaction between blood vessel epicardial substance (Bves) and N-myc downstream regulated gene 4 (NDRG4) is critical for regulation of epicardial cell directional movement, as disruption of this interaction randomizes migratory patterns. Our studies show that Bves/NDRG4 interaction is required for trafficking of internalized fibronectin through the "autocrine extracellular matrix (ECM) deposition" fibronectin recycling pathway. Of importance, we demonstrate that Bves/NDRG4-mediated fibronectin recycling is indeed essential for epicardial cell directional movement, thus linking these two cell processes. Finally, total internal reflectance fluorescence microscopy shows that Bves/NDRG4 interaction is required for fusion of recycling endosomes with the basal cell surface, providing a molecular mechanism of motility substrate delivery that regulates cell directional movement. This is the first evidence of a molecular function for Bves and NDRG4 proteins within broader subcellular trafficking paradigms. These data identify novel regulators of a critical vesicle-docking step required for autocrine ECM deposition and explain how Bves facilitates cell-microenvironment interactions in the regulation of epicardial cell-directed movement.