Myocardial ischemia: From disease to syndrome.
Angina; Chronic coronary syndromes; Coronary artery disease; Ischemic heart disease; Microvascular dysfunction
Although current guidelines on the management of stable coronary artery disease acknowledge that multiple mechanisms may precipitate myocardial ischemia, recommended diagnostic, prognostic and therapeutic algorithms are still focused on obstructive epicardial atherosclerotic lesions, and little progress has been made in identifying management strategies for non-atherosclerotic causes of myocardial ischemia. The purpose of this consensus paper is three-fold: 1) to marshal scientific evidence that obstructive atherosclerosis can co-exist with other mechanisms of ischemic heart disease (IHD); 2) to explore how the awareness of multiple precipitating mechanisms could impact on pre-test probability, provocative test results and treatment strategies; and 3) to stimulate a more comprehensive approach to chronic myocardial ischemic syndromes, consistent with the new understanding of this condition.
Marzilli Mario; Crea Filippo; Morrone Doralisa; Bonow Robert O; Brown David L; Camici Paolo G; Chilian William M; DeMaria Anthony; Guarini Giacinta; Huqi Alda; Merz C Noel Bairey; Pepine Carl; Scali Maria Chiara; Weintraub William S; Boden William E
International journal of cardiology
2020
2020-04-26
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
journalArticle
<a href="http://doi.org/10.1016/j.ijcard.2020.04.074" target="_blank" rel="noreferrer noopener">10.1016/j.ijcard.2020.04.074</a>
TRPV4 deletion protects heart from myocardial infarction-induced adverse remodeling via modulation of cardiac fibroblast differentiation.
Mechanotransduction; TRPV4; Myocardial infarction; Myocardial infarction; TGF-beta1; Rho/Rho kinase; Mechanotransduction; TGF-β1; Myocardial infarction; EXTRACELLULAR matrix; HEART failure; HEART fibrosis; HEART; Cardiac fibroblast; Cardiac fibrosis; Rho/Rho kinase; TRPV4; Cardiac fibroblast; Cardiac fibrosis; DELETION mutation
Cardiac fibrosis caused by adverse cardiac remodeling following myocardial infarction can eventually lead to heart failure. Although the role of soluble factors such as TGF-beta is well studied in cardiac fibrosis following myocardial injury, the physiological role of mechanotransduction is not fully understood. Here, we investigated the molecular mechanism and functional role of TRPV4 mechanotransduction in cardiac fibrosis. TRPV4KO mice, 8 weeks following myocardial infarction (MI), exhibited preserved cardiac function compared to WT mice. Histological analysis demonstrated reduced cardiac fibrosis in TRPV4KO mice. We found that WT CF exhibited hypotonicity-induced calcium influx and extracellular matrix (ECM)-stiffness-dependent differentiation in response to
Adapala Ravi K; Kanugula Anantha K; Paruchuri Sailaja; Chilian William M; Thodeti Charles K
Basic research in cardiology
2020
2020-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
Journal Article
<a href="http://doi.org/10.1007/s00395-020-0775-5" target="_blank" rel="noreferrer noopener">10.1007/s00395-020-0775-5</a>
Experimental animal models of coronary microvascular dysfunction.
Coronary microvascular dysfunction (CMD) is commonly present in patients with metabolic derangements and is increasingly recognized as an important contributor to myocardial ischemia, both in the presence and absence of epicardial coronary atherosclerosis. The latter condition is termed 'ischemia with non-obstructive coronary arteries' (INOCA). Notwithstanding the high prevalence of INOCA, effective treatment remains elusive. Although to date there is no animal model for INOCA, animal models of CMD, one of the hallmarks of INOCA, offer excellent test models for enhancing our understanding of the pathophysiology of CMD and for investigating novel therapies. This article presents an overview of currently available experimental models of CMD - with an emphasis on metabolic derangements as risk factors - in dogs, swine, rabbits, rats and mice. In all the available animal models, metabolic derangements are most often induced by a high fat diet and/or diabetes mellitus via injection of alloxan or streptozotocin, but there is also a wide variety of spontaneous as well as transgenic animal models which develop metabolic derangements. Depending on number, severity and duration of exposure to risk factors - all these animal models show perturbations in coronary microvascular (endothelial) function and structure, similar to what has been observed in patients with INOCA and co-morbid conditions. The use of these animal models will be instrumental in identifying novel therapeutic targets and for the subsequent development and testing of novel therapeutic interventions to combat ischemic heart disease, the number one cause of death worldwide.
Sorop Oana; van de Wouw Jens; Chandler Selena; Ohanyan Vahagn; Tune Johnathan D; Chilian William M; Merkus Daphne; Bender Shawn B; Duncker Dirk J
Cardiovascular research
2020
2020-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
Journal Article
<a href="http://doi.org/10.1093/cvr/cvaa002" target="_blank" rel="noreferrer noopener">10.1093/cvr/cvaa002</a>
Step by Step: Advancing the Understanding of Local Vascular Control.
Editorials; vasodilation; hypoxia; dilation; endothelium; arterial pressure
Chilian William M; Yin Liya; Ohanyan Vahagn
Arteriosclerosis, thrombosis, and vascular biology
2020
2020-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
Journal Article
<a href="http://doi.org/10.1161/ATVBAHA.120.313811" target="_blank" rel="noreferrer noopener">10.1161/ATVBAHA.120.313811</a>
Intravital Microscopy of the Beating Murine Heart to Understand Cardiac Leukocyte Dynamics.
HEART; cardiovascular; leukocyte; intravital microscopy; multiphoton microscopy
Cardiovascular disease is the leading cause of worldwide mortality. Intravital microscopy has provided unprecedented insight into leukocyte biology by enabling the visualization of dynamic responses within living organ systems at the cell-scale. The heart presents a uniquely dynamic microenvironment driven by periodic, synchronous electrical conduction leading to rhythmic contractions of cardiomyocytes, and phasic coronary blood flow. In addition to functions shared throughout the body, immune cells have specific functions in the heart including tissue-resident macrophage-facilitated electrical conduction and rapid monocyte infiltration upon injury. Leukocyte responses to cardiac pathologies, including myocardial infarction and heart failure, have been well-studied using standard techniques, however, certain questions related to spatiotemporal relationships remain unanswered. Intravital imaging techniques could greatly benefit our understanding of the complexities of in vivo leukocyte behavior within cardiac tissue, but these techniques have been challenging to apply. Different approaches have been developed including high frame rate imaging of the beating heart, explantation models, micro-endoscopy, and mechanical stabilization coupled with various acquisition schemes to overcome challenges specific to the heart. The field of cardiac science has only begun to benefit from intravital microscopy techniques. The current focused review presents an overview of leukocyte responses in the heart, recent developments in intravital microscopy for the murine heart, and a discussion of future developments and applications for cardiovascular immunology.
Allan-Rahill Nathaniel H; Lamont Michael R E; Chilian William M; Nishimura Nozomi; Small David M
Frontiers in immunology
2020
1905-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
Journal Article
<a href="http://doi.org/10.3389/fimmu.2020.00092" target="_blank" rel="noreferrer noopener">10.3389/fimmu.2020.00092</a>
A Novel Murine Model to Study Postnatal Coronary Collateral Growth by Lineage Tracing
Jamaiyar Anurag; Juguilon Cody; Richardson Devan; Gadd James; Wang Tao; Enrick Molly; Chilian William M; Yin Liya
Circulation Research
2019
2019-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
Journal Article
<a href="http://doi.org/10.1161/RES.0000000000000311" target="_blank" rel="noreferrer noopener">10.1161/RES.0000000000000311</a>
Exosomes derived from Induced Vascular Progenitor Cells Promote Angiogenesis in vitro and in an in vivo Rat Hindlimb Ischemia Model
angiogenesis; endothelial cell; exosome; microRNA; progenitor cell
Induced vascular progenitor cells (iVPCs) were created as an ideal cell type for regenerative medicine and have been reported to positively promote collateral blood flow and improve cardiac function in a rat model of myocardial ischemia. Exosomes have emerged as a novel biomedicine that mimics the function of the donor cells. We investigated the angiogenic activity of exosomes from induced vascular progenitor cells (iVPC-Exo) as a cell-free therapeutic approach for ischemia. Exosomes from iVPCs and rat aortic endothelial cells (RAECs) were isolated using a combination of ultrafiltration and size-exclusion chromatography. Nanoparticle tracking analysis revealed that exosome isolates fell within the exosomal diameter (<150 nm). These exosomes contained known markers Alix and TSG101, and their morphology was validated using transmission electron microscopy. Compared to RAECs, iVPCs significantly increased the secretion of exosomes. Cardiac microvascular endothelial cells and aortic ring explants were pretreated with RAEC-Exo or iVPC-Exo, and basal medium was used as a control. iVPC-Exo exerted an in vitro angiogenic effect on the proliferation, tube formation, and migration of endothelial cells and stimulated microvessel sprouting in an ex vivo aortic ring assay. Additionally, iVPC-Exo increased blood perfusion in a hindlimb ischemia model. Proangiogenic proteins (pentraxin-3 and insulin-like growth factor-binding protein-3) and microRNAs (-143-3p, -291b, and -20b-5p) were found to be enriched in iVPC-Exo, which may mediate iVPC-Exo induced vascular growth. Our findings demonstrate that treatment with iVPC-Exo promotes angiogenesis in vitro, ex vivo, and in vivo. Collectively, these findings indicate a novel cell-free approach for therapeutic angiogenesis.
Johnson Takerra K; Zhao Lina; Zhu Dihan; Wang Yang; Xiao Yan; Oguljahan Babayewa; Zhao Xueying; Kirlin Ward G; Yin Liya; Chilian William M; Liu Dong
American Journal of Physiology. Heart and Circulatory Physiology
2019
2019-08
<a href="http://doi.org/10.1152/ajpheart.00247.2019" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.00247.2019</a>
Knowns and unknowns of coronary artery development and anomalies.
Dong Feng; Chilian William M; Yin Liya
International journal of cardiology
2019
2019-04
<a href="http://doi.org/10.1016/j.ijcard.2019.01.073" target="_blank" rel="noreferrer noopener">10.1016/j.ijcard.2019.01.073</a>
Corruption of coronary collateral growth in metabolic syndrome: Role of oxidative stress.
Angiogenesis; Mitochondria; Arteriogenesis; Redox-dependent signaling
The myocardium adapts to ischemic insults in a variety of ways. One adaptation is the phenomenon of acute preconditioning, which can greatly ameliorate ischemic damage. However, this effect wanes within a few hours and does not confer chronic protection. A more chronic adaptation is the so-called second window of preconditioning, which enables protection for a few days. The most potent adaptation invoked by the myocardium to minimize the effects of ischemia is the growth of blood vessels in the heart, angiogenesis and arteriogenesis (collateral growth), which prevent the development of ischemia by enabling flow to a jeopardized region of the heart. This brief review examines the mechanisms underlying angiogenesis and arteriogenesis in the heart. The concept of a redox window, which is an optimal redox state for vascular growth, is discussed along with signaling mechanisms invoked by reactive oxygen species that are stimulated during ischemia-reperfusion. Finally, the review discusses of some of the pathologies, especially the metabolic syndrome, that negatively affect collateral growth through the corruption of redox signaling processes.
Pung Yuh Fen; Chilian William M
World journal of cardiology
2010
2010-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.4330/wjc.v2.i12.421" target="_blank" rel="noreferrer noopener">10.4330/wjc.v2.i12.421</a>
Augmentation of Muscle Blood Flow by Ultrasound Cavitation Is Mediated by ATP and Purinergic Signaling.
Adenosine Triphosphate – Metabolism; Adenosine Triphosphate/*metabolism; Animal Studies; Animals; contrast echocardiography; Equipment and Supplies; Hemodynamics; Humans; Inbred C57BL; Male; Mice; microbubbles; Microbubbles; microcirculation; Muscle; Neurotransmitter Agents – Metabolism; perfusion; Purinergic Agents/*metabolism; Signal Transduction; Skeletal – Blood Supply; Skeletal/*blood supply; Ultrasonography – Methods; Ultrasonography/*methods
BACKGROUND: Augmentation of tissue blood flow by therapeutic ultrasound is thought to rely on convective shear. Microbubble contrast agents that undergo ultrasound-mediated cavitation markedly amplify these effects. We hypothesized that purinergic signaling is responsible for shear-dependent increases in muscle perfusion during therapeutic cavitation. METHODS: Unilateral exposure of the proximal hindlimb of mice (with or without ischemia produced by iliac ligation) to therapeutic ultrasound (1.3 MHz, mechanical index 1.3) was performed for 10 minutes after intravenous injection of 2x10(8) lipid microbubbles. Microvascular perfusion was evaluated by low-power contrast ultrasound perfusion imaging. In vivo muscle ATP release and in vitro ATP release from endothelial cells or erythrocytes were assessed by a luciferin-luciferase assay. Purinergic signaling pathways were assessed by studying interventions that (1) accelerated ATP degradation; (2) inhibited P2Y receptors, adenosine receptors, or KATP channels; or (3) inhibited downstream signaling pathways involving endothelial nitric oxide synthase or prostanoid production (indomethacin). Augmentation in muscle perfusion by ultrasound cavitation was assessed in a proof-of-concept clinical trial in 12 subjects with stable sickle cell disease. RESULTS: Therapeutic ultrasound cavitation increased muscle perfusion by 7-fold in normal mice, reversed tissue ischemia for up to 24 hours in the murine model of peripheral artery disease, and doubled muscle perfusion in patients with sickle cell disease. Augmentation in flow extended well beyond the region of ultrasound exposure. Ultrasound cavitation produced an approximately 40-fold focal and sustained increase in ATP, the source of which included both endothelial cells and erythrocytes. Inhibitory studies indicated that ATP was a critical mediator of flow augmentation that acts primarily through either P2Y receptors or adenosine produced by ectonucleotidase activity. Combined indomethacin and inhibition of endothelial nitric oxide synthase abolished the effects of therapeutic ultrasound, indicating downstream signaling through both nitric oxide and prostaglandins. CONCLUSIONS: Therapeutic ultrasound using microbubble cavitation to increase muscle perfusion relies on shear-dependent increases in ATP, which can act through a diverse portfolio of purinergic signaling pathways. These events can reverse hindlimb ischemia in mice for \textgreater24 hours and increase muscle blood flow in patients with sickle cell disease. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT01566890.
Belcik J Todd; Davidson Brian P; Xie Aris; Wu Melinda D; Yadava Mrinal; Qi Yue; Liang Sherry; Chon Chae Ryung; Ammi Azzdine Y; Field Joshua; Harmann Leanne; Chilian William M; Linden Joel; Lindner Jonathan R
Circulation
2017
2017-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/CIRCULATIONAHA.116.024826" target="_blank" rel="noreferrer noopener">10.1161/CIRCULATIONAHA.116.024826</a>
Requisite Role of Kv1.5 Channels in Coronary Metabolic Dilation.
129 Strain; Animals; cardiac function; contrast echocardiography; Coronary Circulation/*physiology; Coronary Vessels/*metabolism; hydrogen peroxide; Inbred C57BL; ion channel; Knockout; Kv1.5 Potassium Channel/*physiology; Mice; Muscle; Smooth; Transgenic; transgenic mice; Vascular/*metabolism; vasodilation; Vasodilation/*physiology; voltage-gated potassium channels
RATIONALE: In the working heart, coronary blood flow is linked to the production of metabolites, which modulate tone of smooth muscle in a redox-dependent manner. Voltage-gated potassium channels (Kv), which play a role in controlling membrane potential in vascular smooth muscle, have certain members that are redox-sensitive. OBJECTIVE: To determine the role of redox-sensitive Kv1.5 channels in coronary metabolic flow regulation. METHODS AND RESULTS: In mice (wild-type [WT], Kv1.5 null [Kv1.5(-/-)], and Kv1.5(-/-) and WT with inducible, smooth muscle-specific expression of Kv1.5 channels), we measured mean arterial pressure, myocardial blood flow, myocardial tissue oxygen tension, and ejection fraction before and after inducing cardiac stress with norepinephrine. Cardiac work was estimated as the product of mean arterial pressure and heart rate. Isolated arteries were studied to establish whether genetic alterations modified vascular reactivity. Despite higher levels of cardiac work in the Kv1.5(-/-) mice (versus WT mice at baseline and all doses of norepinephrine), myocardial blood flow was lower in Kv1.5(-/-) mice than in WT mice. At high levels of cardiac work, tissue oxygen tension dropped significantly along with ejection fraction. Expression of Kv1.5 channels in smooth muscle in the null background rescued this phenotype of impaired metabolic dilation. In isolated vessels from Kv1.5(-/-) mice, relaxation to H2O2 was impaired, but responses to adenosine and acetylcholine were normal compared with those from WT mice. CONCLUSIONS: Kv1.5 channels in vascular smooth muscle play a critical role in coupling myocardial blood flow to cardiac metabolism. Absence of these channels disassociates metabolism from flow, resulting in cardiac pump dysfunction and tissue hypoxia.
Ohanyan Vahagn; Yin Liya; Bardakjian Raffi; Kolz Christopher; Enrick Molly; Hakobyan Tatevik; Kmetz John; Bratz Ian; Luli Jordan; Nagane Masaki; Khan Nadeem; Hou Huagang; Kuppusamy Periannan; Graham Jacqueline; Fu Frances Kwan; Janota Danielle; Oyewumi Moses O; Logan Suzanna; Lindner Jonathan R; Chilian William M
Circulation research
2015
2015-09
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/CIRCRESAHA.115.306642" target="_blank" rel="noreferrer noopener">10.1161/CIRCRESAHA.115.306642</a>
Absence of type VI collagen paradoxically improves cardiac function, structure, and remodeling after myocardial infarction.
Animal; Animals; Apoptosis/physiology; Cardiac/pathology/physiology; Collagen Type VI/*genetics/*metabolism; Disease Models; Echocardiography; Extracellular Matrix/metabolism/pathology; Fibrosis/genetics/pathology/physiopathology; Knockout; Male; Mice; Myocardial Infarction/diagnostic imaging/*genetics/*physiopathology; Myocytes; Ventricular Remodeling/*physiology
RATIONALE: We previously reported that type VI collagen deposition increases in the infarcted myocardium in vivo. To date, a specific role for this nonfibrillar collagen has not been explored in the setting of myocardial infarction (MI). OBJECTIVE: To determine whether deletion of type VI collagen in an in vivo model of post-MI wound healing would alter cardiac function and remodeling in the days to weeks after injury. METHODS AND RESULTS: Wild-type and Col6a1(-/-) mice were subjected to MI, followed by serial echocardiographic and histological assessments. At 8 weeks after MI, infarct size was significantly reduced, ejection fraction was significantly preserved (43.9% +/- 3.3% versus 29.1% +/- 4.3% for wild-type), and left ventricular chamber dilation was attenuated in the Col6a1(-/-) MI group (25.8% +/- 7.9% increase versus 62.6% +/- 16.5% for wild-type). The improvement in cardiac remodeling was evident as early as 10 days after MI in the Col6a1(-/-) mice. Myocyte apoptosis within the infarcted zones was initially greater in the Col6a1(-/-) group 3 days after MI, but by day 14 this was significantly reduced. Collagen deposition also was reduced in the infarcted and remote areas of the Col6a1(-/-) hearts. The reductions in chronic myocyte apoptosis and fibrosis are critical events leading to improved long-term remodeling and functional outcomes. CONCLUSIONS: These unexpected results demonstrate for the first time that deletion of type VI collagen in this knockout model plays a critical protective role after MI by limiting infarct size, chronic apoptosis, aberrant remodeling, and fibrosis, leading to preservation of cardiac function.
Luther Daniel J; Thodeti Charles K; Shamhart Patricia E; Adapala Ravi K; Hodnichak Cheryl; Weihrauch Dorothee; Bonaldo Paolo; Chilian William M; Meszaros J Gary
Circulation research
2012
2012-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/CIRCRESAHA.111.252734" target="_blank" rel="noreferrer noopener">10.1161/CIRCRESAHA.111.252734</a>
Induction of vascular progenitor cells from endothelial cells stimulates coronary collateral growth.
*Collateral Circulation; *Coronary Circulation; Animal; Animals; Biomarkers/metabolism; Cell Differentiation; Cell Lineage; Cells; Coronary Occlusion/genetics/metabolism/pathology/physiopathology/*surgery; Coronary Vessels/metabolism/pathology/*physiopathology; Cultured; Developmental; Disease Models; Endothelial Cells/metabolism/pathology/*transplantation; Epigenesis; Gene Expression Profiling; Gene Expression Regulation; Genetic; Induced Pluripotent Stem Cells/metabolism/*transplantation; Mice; Muscle; Myocytes; Neovascularization; Physiologic; Rats; Regenerative Medicine/methods; Regional Blood Flow; Reverse Transcriptase Polymerase Chain Reaction; SCID; Smooth; Smooth Muscle/metabolism/pathology/*transplantation; Sprague-Dawley; Teratoma/metabolism/pathology; Time Factors; Transcription Factors/genetics/metabolism; Transduction; Vascular/metabolism/pathology/*physiopathology
RATIONALE: A well-developed coronary collateral circulation improves the morbidity and mortality of patients following an acute coronary occlusion. Although regenerative medicine has great potential in stimulating vascular growth in the heart, to date there have been mixed results, and the ideal cell type for this therapy has not been resolved. OBJECTIVE: To generate induced vascular progenitor cells (iVPCs) from endothelial cells, which can differentiate into vascular smooth muscle cells (VSMCs) or endothelial cells (ECs), and test their capability to stimulate coronary collateral growth. METHODS AND RESULTS: We reprogrammed rat ECs with the transcription factors Oct4, Klf4, Sox2, and c-Myc. A population of reprogrammed cells was derived that expressed pluripotent markers Oct4, SSEA-1, Rex1, and AP and hemangioblast markers CD133, Flk1, and c-kit. These cells were designated iVPCs because they remained committed to vascular lineage and could differentiate into vascular ECs and VSMCs in vitro. The iVPCs demonstrated better in vitro angiogenic potential (tube network on 2-dimensional culture, tube formation in growth factor reduced Matrigel) than native ECs. The risk of teratoma formation in iVPCs is also reduced in comparison with fully reprogrammed induced pluripotent stem cells (iPSCs). When iVPCs were implanted into myocardium, they engrafted into blood vessels and increased coronary collateral flow (microspheres) and improved cardiac function (echocardiography) better than iPSCs, mesenchymal stem cells, native ECs, and sham treatments. CONCLUSIONS: We conclude that iVPCs, generated by partially reprogramming ECs, are an ideal cell type for cell-based therapy designed to stimulate coronary collateral growth.
Yin Liya; Ohanyan Vahagn; Pung Yuh Fen; Delucia Angelo; Bailey Erin; Enrick Molly; Stevanov Kelly; Kolz Christopher L; Guarini Giacinta; Chilian William M
Circulation research
2012
2012-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/CIRCRESAHA.111.250126" target="_blank" rel="noreferrer noopener">10.1161/CIRCRESAHA.111.250126</a>
A brief etymology of the collateral circulation.
*Cardiology; *Collateral Circulation/physiology; *Terminology as Topic; Blood Vessels/embryology/growth & development; collateral circulation; Humans; myocardial ischemia; Neovascularization; peripheral arterial disease; Physiologic/physiology; stroke
It is well known that the protective capacity of the collateral circulation falls short in many individuals with ischemic disease of the heart, brain, and lower extremities. In the past 15 years, opportunities created by molecular and genetic tools, together with disappointing outcomes in many angiogenic trials, have led to a significant increase in the number of studies that focus on: understanding the basic biology of the collateral circulation; identifying the mechanisms that limit the collateral circulation's capacity in many individuals; devising methods to measure collateral extent, which has been found to vary widely among individuals; and developing treatments to increase collateral blood flow in obstructive disease. Unfortunately, accompanying this increase in reports has been a proliferation of vague terms used to describe the disposition and behavior of this unique circulation, as well as the increasing misuse of well-ensconced ones by new (and old) students of collateral circulation. With this in mind, we provide a brief glossary of readily understandable terms to denote the formation, adaptive growth, and maladaptive rarefaction of collateral circulation. We also propose terminology for several newly discovered processes that occur in the collateral circulation. Finally, we include terms used to describe vessels that are sometimes confused with collaterals, as well as terms describing processes active in the general arterial-venous circulation when ischemic conditions engage the collateral circulation. We hope this brief review will help unify the terminology used in collateral research.
Faber James E; Chilian William M; Deindl Elisabeth; van Royen Niels; Simons Michael
Arteriosclerosis, thrombosis, and vascular biology
2014
2014-09
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/ATVBAHA.114.303929" target="_blank" rel="noreferrer noopener">10.1161/ATVBAHA.114.303929</a>
Mitochondrial oxidative stress corrupts coronary collateral growth by activating adenosine monophosphate activated kinase-alpha signaling.
AMP-Activated Protein Kinases/*metabolism; Animal; Animals; Body Weight/physiology; Cells; collateral circulation; coronary circulation; Coronary Vessels/cytology/*enzymology; Cultured; Disease Models; Endothelial Cells/cytology/*enzymology; Humans; Inbred WKY; Ischemia/metabolism/pathology; mitochondria; Mitochondria/drug effects/*metabolism; Myocardium/enzymology/pathology; Oxidative Stress/*physiology; Rats; reactive oxygen species; Rotenone/pharmacology; Signal Transduction/*physiology; TOR Serine-Threonine Kinases/metabolism; Uncoupling Agents/pharmacology
OBJECTIVE: Our goal was to determine the mechanism by which mitochondrial oxidative stress impairs collateral growth in the heart. APPROACH AND RESULTS: Rats were treated with rotenone (mitochondrial complex I inhibitor that increases reactive oxygen species production) or sham-treated with vehicle and subjected to repetitive ischemia protocol for 10 days to induce coronary collateral growth. In control rats, repetitive ischemia increased flow to the collateral-dependent zone; however, rotenone treatment prevented this increase suggesting that mitochondrial oxidative stress compromises coronary collateral growth. In addition, rotenone also attenuated mitochondrial complex I activity and led to excessive mitochondrial aggregation. To further understand the mechanistic pathway(s) involved, human coronary artery endothelial cells were treated with 50 ng/mL vascular endothelial growth factor, 1 micromol/L rotenone, and rotenone/vascular endothelial growth factor for 48 hours. Vascular endothelial growth factor induced robust tube formation; however, rotenone completely inhibited this effect (P\textless0.05 rotenone versus vascular endothelial growth factor treatment). Inhibition of tube formation by rotenone was also associated with significant increase in mitochondrial superoxide generation. Immunoblot analyses of human coronary artery endothelial cells with rotenone treatment showed significant activation of adenosine monophosphate activated kinase (AMPK)-alpha and inhibition of mammalian target of rapamycin and p70 ribosomal S6 kinase. Activation of AMPK-alpha suggested impairments in energy production, which was reflected by decrease in O2 consumption and bioenergetic reserve capacity of cultured cells. Knockdown of AMPK-alpha (siRNA) also preserved tube formation during rotenone, suggesting the negative effects were mediated by the activation of AMPK-alpha. Conversely, expression of a constitutively active AMPK-alpha blocked tube formation. CONCLUSIONS: We conclude that activation of AMPK-alpha during mitochondrial oxidative stress inhibits mammalian target of rapamycin signaling, which impairs phenotypic switching necessary for the growth of blood vessels.
Pung Yuh Fen; Sam Wai Johnn; Stevanov Kelly; Enrick Molly; Chen Chwen-Lih; Kolz Christopher; Thakker Prashanth; Hardwick James P; Chen Yeong-Renn; Dyck Jason R B; Yin Liya; Chilian William M
Arteriosclerosis, thrombosis, and vascular biology
2013
2013-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/ATVBAHA.113.301591" target="_blank" rel="noreferrer noopener">10.1161/ATVBAHA.113.301591</a>
Resolution of mitochondrial oxidative stress rescues coronary collateral growth in Zucker obese fatty rats.
Animal; Animals; Antioxidants/*pharmacology; Collateral Circulation/*drug effects/physiology; Coronary Vessels/drug effects/*growth & development; Disease Models; Heart/*drug effects/physiology; Lipid Peroxidation/drug effects/physiology; Lipid Peroxides/metabolism; Male; Metabolic Syndrome/*metabolism/physiopathology; Mitochondria; Mitochondrial Proteins/metabolism; Obesity/*metabolism/physiopathology; Organophosphorus Compounds/pharmacology; Oxidative Stress/*drug effects/physiology; Piperidines/pharmacology; Rats; Reactive Oxygen Species/metabolism; Ubiquinone/pharmacology; Zucker
OBJECTIVE: We have previously found abrogated ischemia-induced coronary collateral growth in Zucker obese fatty (ZOF) rats compared with Zucker lean (ZLN) rats. Because ZOF rats have structural abnormalities in their mitochondria suggesting dysfunction and also show increased production of O(2), we hypothesized that mitochondrial dysfunction caused by oxidative stress impairs coronary collateral growth in ZOF. METHODS AND RESULTS: Increased levels of reactive oxygen species were observed in aortic endothelium and smooth muscle cells in ZOF rats compared with ZLN rats. Reactive oxygen species levels were decreased by the mitochondria-targeted antioxidants MitoQuinone (MQ) and MitoTempol (MT) as assessed by MitoSox Red and dihydroethidine staining. Lipid peroxides (a marker of oxidized lipids) were increased in ZOF by approximately 47% compared with ZLN rats. The elevation in oxidative stress was accompanied by increased antioxidant enzymes, except glutathione peroxidase-1, and by increased uncoupling protein-2 in ZOF versus ZLN rats. In addition, elevated respiration rates were also observed in the obese compared with lean rats. Administration of MQ significantly normalized the metabolic profiles and reduced lipid peroxides in ZOF rats to the same level observed in lean rats. The protective effect of MQ also suppressed the induction of uncoupling protein-2 in the obese rats. Resolution of mitochondrial oxidative stress by MQ or MT restored coronary collateral growth to the same magnitude observed in ZLN rats in response to repetitive ischemia. CONCLUSIONS: We conclude that mitochondrial oxidative stress and dysfunction play a key role in disrupting coronary collateral growth in obesity and the metabolic syndrome, and elimination of the mitochondrial oxidative stress with MQ or MT rescues collateral growth.
Pung Yuh Fen; Rocic Petra; Murphy Michael P; Smith Robin A J; Hafemeister Jennifer; Ohanyan Vahagn; Guarini Giacinta; Yin Liya; Chilian William M
Arteriosclerosis, thrombosis, and vascular biology
2012
2012-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/ATVBAHA.111.241802" target="_blank" rel="noreferrer noopener">10.1161/ATVBAHA.111.241802</a>
Connecting the dots–establishing causality between chronic stress, depression, and cardiovascular disease.
Animal/*physiology; Animals; Behavior; Depression/*physiopathology; Endothelium; Female; Male; Psychological/*physiopathology; Stress; Vascular Diseases/*physiopathology; Vascular/*physiopathology
Di Vincenzo Lola; Reber Megan; Perera Vidushani; Chilian William M
Journal of applied physiology (Bethesda, Md. : 1985)
2014
2014-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/japplphysiol.00856.2014" target="_blank" rel="noreferrer noopener">10.1152/japplphysiol.00856.2014</a>
Optimal reactive oxygen species concentration and p38 MAP kinase are required for coronary collateral growth.
*Collateral Circulation/drug effects; *Coronary Circulation/drug effects; *MAP Kinase Signaling System/drug effects; Acetophenones/pharmacology; Animal; Animals; Blood Flow Velocity; Cells; Coronary Vessels/surgery; Cultured; Disease Models; Ditiocarb/pharmacology; Endothelial Cells/drug effects/enzymology/*metabolism; Enzyme Inhibitors/pharmacology; Humans; Imidazoles/pharmacology; Inbred WKY; Ligation; Male; Myocardial Reperfusion Injury/enzymology/metabolism/*physiopathology; NADPH Oxidases/antagonists & inhibitors/metabolism; Neovascularization; Onium Compounds/pharmacology; Oxygenases/antagonists & inhibitors/metabolism; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/*metabolism; Physiologic; Pyridines/pharmacology; Rats; Reactive Oxygen Species/*metabolism; Superoxide Dismutase/antagonists & inhibitors/metabolism; Vascular Endothelial Growth Factor A/metabolism
Reactive oxygen species (ROS) are implicated in coronary collateral growth (CCG). We evaluated the requirement for ROS in human coronary artery endothelial cell (HCAEC) tube formation, CCG in vivo, and signaling (p38 MAP kinase) by which ROS may stimulate vascular growth. The flavin-containing oxidase inhibitor diphenyleneiodonium (DPI) or the superoxide dismutase inhibitor diethyldithiocarbamate (DETC) blocked vascular endothelial growth factor-induced HCAEC tube formation in Matrigel. We assessed the effect of DPI and DETC on CCG in a rat model of repetitive ischemia (RI) (40 s left anterior descending coronary artery occlusion every 20 min for 2 h 20 min, 3 times/day, 10 days). DPI or DETC was given intraperitoneally, or the NAD(P)H oxidase inhibitor apocynin was given in drinking water. Collateral-dependent flow (measured by using microspheres) was expressed as a ratio of normal and ischemic zone flows. In sham-operated rats, collateral flow in the ischemic zone was 18 +/- 6% of normal zone; in the RI group, collateral flow in the ischemic zone was 83 +/- 5% of normal zone. DPI prevented the increase in collateral flow after RI (25 +/- 4% of normal zone). Similar results were obtained with apocynin following RI (32 +/- 7% of that in the normal zone). DETC achieved similar results (collateral flow after RI was 21 +/- 2% of normal zone). DPI and DETC blocked RI-induced p38 MAP kinase activation in response to vascular endothelial growth factor and RI. These results demonstrate a requirement for optimal ROS concentration in HCAEC tube formation, CCG, and p38 MAP kinase activation. p38 MAP kinase inhibition prevented HCAEC tube formation and partially blocked RI-induced CCG (42 +/- 7% of normal zone flow), indicating that p38 MAP kinase is a critical signaling mediator of CCG.
Rocic Petra; Kolz Christopher; Reed Ryan; Potter Barry; Chilian William M
American journal of physiology. Heart and circulatory physiology
2007
2007-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.01330.2006" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.01330.2006</a>
The JCR:LA-cp rat: a novel rodent model of cystic medial necrosis.
*Rats; Animal; Animals; Aortic Aneurysm; Atherosclerosis/pathology; Blood Glucose/metabolism; Blood Vessels/pathology; Body Weight; Collagen/biosynthesis; Cysts/*genetics/pathology; Disease Models; hypoxia; Hypoxia; Inbred Strains; leptin; Lipids/blood; Male; metabolic syndrome; Metabolic Syndrome/*genetics/pathology; Necrosis; Proteoglycans/biosynthesis; Rats; rodent model; Thoracic/*genetics/pathology
Although there are multiple rodent models of the metabolic syndrome, very few develop vascular complications. In contrast, the JCR:LA-cp rat develops both metabolic syndrome and early atherosclerosis in predisposed areas. However, the pathology of the normal vessel wall has not been described. We examined JCR:LA control (+/+) or cp/cp rats fed normal chow diet for 6 or 18 mo. JCR:LA-cp rats developed multiple features of advanced cystic medial necrosis including "cysts," increased collagen formation and proteoglycan deposition around cysts, apoptosis of vascular smooth muscle cells, and spotty medial calcification. These appearances began within 6 mo and were extensive by 18 mo. JCR:LA-cp rats had reduced medial cellularity, increased medial thickness, and vessel hypoxia that was most marked in the adventitia. In conclusion, the normal chow-fed JCR:LA-cp rat represents a novel rodent model of cystic medial necrosis, associated with multiple metabolic abnormalities, vascular smooth muscle cell apoptosis, and vessel hypoxia.NEW & NOTEWORTHY Triggers for cystic medial necrosis (CMN) have been difficult to study due to lack of animal models to recapitulate the pathologies seen in humans. Our study is the first description of CMN in the rat. Thus the JCR:LA-cp rat represents a useful model to investigate the underlying molecular changes leading to the development of CMN.
Pung Yuh Fen; Chilian William M; Bennett Martin R; Figg Nichola; Kamarulzaman Mohd Hamzah
American journal of physiology. Heart and circulatory physiology
2017
2017-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.00653.2016" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.00653.2016</a>
Early upregulation of myocardial CXCR4 expression is critical for dimethyloxalylglycine-induced cardiac improvement in acute myocardial infarction.
alpha Subunit/metabolism; Amino Acids; Animal; Animals; Apoptosis/drug effects; Cardiotonic Agents/*pharmacology; Cell Hypoxia; Cell Line; CXCR4/deficiency/genetics/*metabolism; Dicarboxylic/*pharmacology; Disease Models; Enzyme Inhibitors/pharmacology; hypoxia; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor-Proline Dioxygenases/antagonists & inhibitors/metabolism; Inbred C57BL; Knockout; Left/*drug effects; Mice; myocardial infarction; Myocardial Infarction/*drug therapy/genetics/metabolism/pathology/physiopathology; Myocardium/*metabolism/pathology; Rats; Receptors; Recovery of Function; Signal Transduction/drug effects; stem cells; Stem Cells/drug effects/metabolism; Stroke Volume/drug effects; Time Factors; Up-Regulation; Ventricular Function
The stromal cell-derived factor-1 (SDF-1):CXCR4 is important in myocardial repair. In this study we tested the hypothesis that early upregulation of cardiomyocyte CXCR4 (CM-CXCR4) at a time of high myocardial SDF-1 expression could be a strategy to engage the SDF-1:CXCR4 axis and improve cardiac repair. The effects of the hypoxia inducible factor (HIF) hydroxylase inhibitor dimethyloxalylglycine (DMOG) on CXCR4 expression was tested on H9c2 cells. In mice a myocardial infarction (MI) was produced in CM-CXCR4 null and wild-type controls. Mice were randomized to receive injection of DMOG (DMOG group) or saline (Saline group) into the border zone after MI. Protein and mRNA expression of CM-CXCR4 were quantified. Echocardiography was used to assess cardiac function. During hypoxia, DMOG treatment increased CXCR4 expression of H9c2 cells by 29 and 42% at 15 and 24 h, respectively. In vivo DMOG treatment increased
Mayorga Mari; Kiedrowski Matthew; Shamhart Patricia; Forudi Farhad; Weber Kristal; Chilian William M; Penn Marc S; Dong Feng
American journal of physiology. Heart and circulatory physiology
2016
2016-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.00449.2015" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.00449.2015</a>
Redox-dependent coronary metabolic dilation.
*Paracrine Communication; *Vasodilation/drug effects; Acetylcysteine/pharmacology; Animals; Antioxidants/pharmacology; Cardiac/drug effects/*metabolism; Conditioned/metabolism; Coronary Vessels/drug effects/enzymology/*metabolism; Culture Media; Dithiothreitol/pharmacology; Enzyme Activation; Fluorescence; Hydrogen Peroxide/metabolism; Imidazoles/pharmacology; In Vitro Techniques; Microscopy; Myocytes; Nitroprusside/pharmacology; Oxidation-Reduction; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/metabolism; Phosphorylation; Protein Kinase Inhibitors/pharmacology; Pyridines/pharmacology; Rats; Reactive Oxygen Species/*metabolism; Reducing Agents/pharmacology; Sulfhydryl Compounds/*metabolism; Vasodilator Agents/pharmacology; Wistar
We have observed that hydrogen peroxide (H2O2), the dismutated product of superoxide, is a coronary metabolic dilator and couples myocardial oxygen consumption to coronary blood flow. Because the chemical activity of H2O2 favors its role as an oxidant, and thiol groups are susceptible to oxidation, we hypothesized that coronary metabolic dilation occurs via a redox mechanism involving thiol oxidation. To test this hypothesis, we studied the mechanisms of dilation of isolated coronary arterioles to metabolites released by metabolically active (paced at 400 min) isolated cardiac myocytes and directly compared these responses with authentic H2O2. Studies were performed under control conditions and using interventions designed to reduce oxidized thiols [0.1 microM dithiothreitol (DTT) and 10 mM N-acetyl-L-cysteine (NAC)]. Aliquots of the conditioned buffer from paced myocytes produced vasodilation of isolated arterioles (peak response, 71% +/- 6% of maximal dilation), whereas H2O2 produced complete dilation (92% +/- 7%). Dilation to either the conditioned buffer or to H2O2 was significantly reduced by the administration of either NAC or DTT. The location of the thiols oxidized by the conditioned buffer or of H2O2 was determined by the administration of the fluorochromes monochlorobimane (20 microM) or monobromotrimethylammoniobimane (20 microM), which covalently label the reduced total or extracellular-reduced thiols, respectively. H2O2 or the conditioned buffer predominantly oxidized intracellular thiols since the fluorescent signal from monochlorobimane was reduced more than that of monobromotrimethylammoniobimane. To determine whether one of the intracellular targets of thiol oxidation that leads to dilation is the redox-sensitive kinase p38 mitogen-activated protein (MAP) kinase, we evaluated dilation following the administration of the p38 inhibitor SB-203580 (10 microM). The inhibition of p38 attenuated dilation to either H2O2 or to the conditioned buffer from stimulated myocytes by a similar degree, but SB-203580 did not attenuate dilation to nitroprusside. Western blot analysis for the activated form of p38 (phospho-p38) in the isolated aortae revealed robust activation of this enzyme by H2O2. Taken together, our results show that an active component of cardiac metabolic dilation, like that of H2O2, produces dilation by the oxidation of thiols, which are predominantly intracellular and dependent activation on the p38 MAP kinase. Thus coronary metabolic dilation appears to be mediated by redox-dependent signals.
Saitoh Shu-ichi; Kiyooka Takahiko; Rocic Petra; Rogers Paul A; Zhang Cuihua; Swafford Albert; Dick Gregory M; Viswanathan Chandrasekar; Park Yoonjung; Chilian William M
American journal of physiology. Heart and circulatory physiology
2007
2007-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.00436.2007" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.00436.2007</a>
Cardioprotection during ischemia by coronary collateral growth.
cardioprotection; coronary circulation; coronary collateral growth; ischemia
Ischemic heart diseases (IHD) cause millions of deaths around the world annually. While surgical and pharmacological interventions are commonly used to treat patients with IHD, their efficacy varies from patient to patient and is limited by the severity of the disease. One promising, at least theoretically, approach for treating IHD is induction of coronary collateral growth (CCG). Coronary collaterals are arteriole-to-arteriole anastomoses that can undergo expansion and remodeling in the setting of coronary disease when the disease elicits myocardial ischemia and creates a pressure difference across the collateral vessel that creates unidirectional flow. Well-developed collaterals can restore blood flow in the ischemic area of the myocardium and protect the myocardium at risk. Moreover, such collaterals are correlated to reduced mortality and infarct size and better cardiac function during occlusion of coronary arteries. Therefore, understanding the process of CCG is highly important as a potentially viable treatment of IHD. While there are several excellent review articles on this topic, this review will provide a unified overview of the various aspects related to CCG as well as an update of the advancements in the field. We also call for more detailed studies with an interdisciplinary approach to advance our knowledge of CCG. In this review, we will describe growth of coronary collaterals, the various factors that contribute to CCG, animal models used to study CCG, and the cardioprotective effects of coronary collaterals during ischemia. We will also discuss the impairment of CCG in metabolic syndrome and the therapeutic potentials of CCG in IHD.
Jamaiyar Anurag; Juguilon Cody; Dong Feng; Cumpston Devan; Enrick Molly; Chilian William M; Yin Liya
American journal of physiology. Heart and circulatory physiology
2019
2019-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.00145.2018" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.00145.2018</a>
The role of mitochondrial bioenergetics and reactive oxygen species in coronary collateral growth.
*Collateral Circulation; *Coronary Circulation; *Energy Metabolism; *Neovascularization; angiogenesis; Animals; arteriogenesis; Coronary Vessels/metabolism; Humans; mitochondria; Mitochondria; Mitochondrial Proteins/metabolism; Muscle; Muscle/*metabolism; Myocytes; Oxidative Stress; Phenotype; Physiologic; Reactive Oxygen Species/*metabolism; redox-dependent signaling; Signal Transduction; Smooth; Smooth Muscle/*metabolism; Vascular/*metabolism
Coronary collateral growth is a process involving coordination between growth factors expressed in response to ischemia and mechanical forces. Underlying this response is proliferation of vascular smooth muscle and endothelial cells, resulting in an enlargement in the caliber of arterial-arterial anastomoses, i.e., a collateral vessel, sometimes as much as an order of magnitude. An integral element of this cell proliferation is the process known as phenotypic switching in which cells of a particular phenotype, e.g., contractile vascular smooth muscle, must change their phenotype to proliferate. Phenotypic switching requires that protein synthesis occurs and different kinase signaling pathways become activated, necessitating energy to make the switch. Moreover, kinases, using ATP to phosphorylate their targets, have an energy requirement themselves. Mitochondria play a key role in the energy production that enables phenotypic switching, but under conditions where mitochondrial energy production is constrained, e.g., mitochondrial oxidative stress, this switch is impaired. In addition, we discuss the potential importance of uncoupling proteins as modulators of mitochondrial reactive oxygen species production and bioenergetics, as well as the role of AMP kinase as an energy sensor upstream of mammalian target of rapamycin, the master regulator of protein synthesis.
Pung Yuh Fen; Sam Wai Johnn; Hardwick James P; Yin Liya; Ohanyan Vahagn; Logan Suzanna; Di Vincenzo Lola; Chilian William M
American journal of physiology. Heart and circulatory physiology
2013
2013-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.00077.2013" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.00077.2013</a>
Kv1.3 channels facilitate the connection between metabolism and blood flow in the heart.
*contrast echocardiography; *coronary blood flow; *Coronary Circulation/drug effects; *coronary microcirculation; *Kv 1.3 channels; Animals; Kv1.3 Potassium Channel/*physiology; Mice; Myocardium/*metabolism; Potassium Channel Blockers/pharmacology; Regional Blood Flow/drug effects; Triterpenes/pharmacology; Vasodilation/drug effects
The connection between metabolism and flow in the heart, metabolic dilation, is essential for cardiac function. We recently found redox-sensitive Kv1.5 channels play a role in coronary metabolic dilation; however, more than one ion channel likely plays a role in this process as animals null for these channels still showed limited coronary metabolic dilation. Accordingly, we examined the role of another Kv1 family channel, the energetically linked Kv1.3 channel, in coronary metabolic dilation. We measured myocardial blood flow (contrast echocardiography) during norepinephrine-induced increases in cardiac work (heart rate x mean arterial pressure) in WT, WT mice given correolide (preferential Kv1.3 antagonist), and Kv1.3-null mice (Kv1.3(-/-) ). We also measured relaxation of isolated small arteries mounted in a myograph. During increased cardiac work, myocardial blood flow was attenuated in Kv1.3(-/-) and in correolide-treated mice. In isolated vessels from Kv1.3(-/-) mice, relaxation to H2 O2 was impaired (vs WT), but responses to adenosine and acetylcholine were equivalent to WT. Correolide reduced dilation to adenosine and acetylcholine in WT and Kv1.3(-/-) , but had no effect on H2 O2 -dependent dilation in vessels from Kv1.3(-/-) mice. We conclude that Kv1.3 channels participate in the connection between myocardial blood flow and cardiac metabolism.
Ohanyan Vahagn; Yin Liya; Bardakjian Raffi; Kolz Christopher; Enrick Molly; Hakobyan Tatevik; Luli Jordan; Graham Kathleen; Khayata Mohamed; Logan Suzanna; Kmetz John; Chilian William M
Microcirculation (New York, N.Y. : 1994)
2017
2017-05
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1111/micc.12334" target="_blank" rel="noreferrer noopener">10.1111/micc.12334</a>
Novel noncanonical regulation of soluble VEGF/VEGFR2 signaling by mechanosensitive ion channel TRPV4.
angiogenesis; endothelial cell; phosphorylation
VEGF signaling via VEGF receptor-2 (VEGFR2) is a major regulator of endothelial cell (EC) functions, including angiogenesis. Although most studies of angiogenesis focus on soluble VEGF signaling, mechanical signaling also plays a critical role. Here, we examined the consequence of disruption of mechanical signaling on soluble signaling pathways. Specifically, we observed that small interfering RNA (siRNA) knockdown of a mechanosensitive ion channel, transient receptor potential vanilloid 4 (TRPV4), significantly reduced perinuclear (Golgi) VEGFR2 in human ECs with a concomitant increase in phosphorylation at Y1175 and membrane translocation. TRPV4 knockout (KO) ECs exhibited increased plasma membrane localization of phospho-VEGFR2 compared with normal ECs. The knockdown also increased phospho-VEGFR2 in whole cell lysates and membrane fractions compared with control siRNA-treated cells. siRNA knockdown of TRPV4 enhanced nuclear localization of mechanosensitive transcription factors, yes-associated protein/transcriptional coactivator with PDZ-binding motif via rho kinase, which were shown to increase VEGFR2 trafficking to the plasma membrane. Furthermore, TRPV4 deletion/knockdown enhanced VEGF-mediated migration in vitro and increased expression of VEGFR2 in vivo in the vasculature of TRPV4 KO tumors compared with wild-type tumors. Our results thus show that TRPV4 channels regulate VEGFR2 trafficking and activation to identify novel cross-talk between mechanical (TRPV4) and soluble (VEGF) signaling that controls EC migration and angiogenesis.-Kanugula, A. K., Adapala, R. K., Midha, P., Cappelli, H. C., Meszaros, J. G., Paruchuri, S., Chilian, W. M., Thodeti, C. K., Novel noncanonical regulation of soluble VEGF/VEGFR2 signaling by mechanosensitive ion channel TRPV4.
Kanugula Anantha K; Adapala Ravi K; Midha Priya; Cappelli Holly C; Meszaros J Gary; Paruchuri Sailaja; Chilian William M; Thodeti Charles K
FASEB journal : official publication of the Federation of American Societies for Experimental Biology
2019
2019-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1096/fj.201800509R" target="_blank" rel="noreferrer noopener">10.1096/fj.201800509R</a>
Redox-dependent mechanisms in coronary collateral growth: the "redox window" hypothesis.
Angiotensin II/physiology; Animals; Coronary Vessels/*growth & development/metabolism; Humans; Oxidation-Reduction; Reactive Oxygen Species/metabolism
This review addresses the complexity of coronary collateral growth from the aspect of redox signaling and introduces the concept of a "redox window" in the context of collateral growth. In essence, the redox window constitutes a range in the redox state of cells, which not only is permissive for the actions of growth factors but also amplifies their actions. The interactions of redox-dependent signaling with growth factors are well established through the actions of many redox-dependent kinases (e.g., Akt and p38 mitogen-activated protein kinase). The initial changes in cellular redox can be induced by a variety of events, from the oxidative burst during reperfusion after ischemia, to recruitment of various types of inflammatory cells capable of producing reactive oxygen species. Any event that "upsets" the normal redox equilibrium is capable of amplifying growth. However, extremes of the redox window, oxidative and reductive stresses, are associated with diminished growth-factor signaling and reduced activation of redox-dependent kinases. This concept of a redox window helps to explain why the clinical trials aimed at stimulating coronary collateral growth, the "therapeutic angiogenesis trials," failed. However, understanding of redox signaling in the context of coronary collateral growth could provide new paradigms for stimulating collateral growth in patients.
Yun June; Rocic Petra; Pung Yuh Fen; Belmadani Souad; Carrao Ana Catarina Ribeiro; Ohanyan Vahagn; Chilian William M
Antioxidants & redox signaling
2009
2009-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1089/ars.2009.2476" target="_blank" rel="noreferrer noopener">10.1089/ars.2009.2476</a>
Overexpressing superoxide dismutase 2 induces a supernormal cardiac function by enhancing redox-dependent mitochondrial function and metabolic dilation.
Adenosine Triphosphate/biosynthesis; Animals; Arterial Pressure/drug effects; Bioenergetics; Blood Flow Velocity/drug effects; Cardiac function; Cardiac/drug effects/*enzymology; Catalase/pharmacology; Echocardiography; Female; Gene Expression; Heart/drug effects/*enzymology; Hydrogen Peroxide/*metabolism/pharmacology; Injections; Intravenous; Male; Metabolic dilation; Mice; Mitochondria; Myocardium/*enzymology; Myocytes; NG-Nitroarginine Methyl Ester/pharmacology; Oxidation-Reduction; Oxygen Consumption/drug effects; Redox regulation; Signal Transduction; Stroke Volume/drug effects; Superoxide dismutase 2 (SOD2); Superoxide Dismutase/*genetics/metabolism; Transgenic; Transgenic mice; Vasodilation/*drug effects
During heightened cardiac work, O2 consumption by the heart benefits energy production via mitochondria. However, some electrons leak from the respiratory chain and yield superoxide, which is rapidly metabolized into H2O2 by SOD2. To understand the systemic effects of the metabolic dilator, H2O2, we studied mice with cardiac-specific SOD2 overexpression (SOD2-tg), which increases the H2O2 produced by cardiac mitochondria. Contrast echocardiography was employed to evaluate cardiac function, indicating that SOD2-tg had a significantly greater ejection fraction and a lower mean arterial pressure (MAP) that was partially normalized by intravenous injection of catalase. Norepinephrine-mediated myocardial blood flow (MBF) was significantly enhanced in SOD2-tg mice. Coupling of MBF to the double product (Heart RatexMAP) was increased in SOD2-tg mice, indicating that the metabolic dilator, "spilled" over, inducing systemic vasodilation. The hypothesis that SOD2 overexpression effectively enhances mitochondrial function was further evaluated. Mitochondria of SOD2-tg mice had a decreased state 3 oxygen consumption rate, but maintained the same ATP production flux under the basal and L-NAME treatment conditions, indicating a higher bioenergetic efficiency. SOD2-tg mitochondria produced less superoxide, and had lower redox activity in converting cyclic hydroxylamine to stable nitroxide, and a lower GSSG concentration. EPR analysis of the isolated mitochondria showed a significant decrease in semiquinones at the SOD2-tg Qi site. These results support a more reductive physiological setting in the SOD2-tg murine heart. Cardiac mitochondria exhibited no significant differences in the respiratory control index between WT and SOD2-tg. We conclude that SOD2 overexpression in myocytes enhances mitochondrial function and metabolic vasodilation, leading to a phenotype of supernormal cardiac function.
Kang Patrick T; Chen Chwen-Lih; Ohanyan Vahagn; Luther Daniel J; Meszaros J Gary; Chilian William M; Chen Yeong-Renn
Journal of molecular and cellular cardiology
2015
2015-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.yjmcc.2015.09.001" target="_blank" rel="noreferrer noopener">10.1016/j.yjmcc.2015.09.001</a>
TRPV4 channels mediate cardiac fibroblast differentiation by integrating mechanical and soluble signals.
*Calcium Signaling; *Cell Differentiation; *Mechanotransduction; Animals; Cellular; Extracellular Matrix/metabolism/physiology; Fibroblasts/*physiology; Gene Knockdown Techniques; Male; Monoterpenes/pharmacology; Myocardium/cytology; Myofibroblasts/metabolism; Rats; RNA; Small Interfering/genetics; Sprague-Dawley; Transforming Growth Factor beta1/physiology; TRPM Cation Channels/antagonists & inhibitors/metabolism; TRPV Cation Channels/genetics/*metabolism
The phenotypic switch underlying the differentiation of cardiac fibroblasts into hypersecretory myofibroblasts is critical for cardiac remodeling following myocardial infarction. Myofibroblasts facilitate wound repair in the myocardium by secreting and organizing extracellular matrix (ECM) during the wound healing process. However, the molecular mechanisms involved in myofibroblast differentiation are not well known. TGF-beta has been shown to promote differentiation and this, combined with the robust mechanical environment in the heart, lead us to hypothesize that the mechanotransduction and TGF-beta signaling pathways play active roles in the differentiation of cardiac fibroblasts to myofibroblasts. Here, we show that the mechanosensitve ion channel TRPV4 is required for TGF-beta1-induced differentiation of cardiac fibroblasts into myofibroblasts. We found that the TRPV4-specific antagonist AB159908 and siRNA knockdown of TRPV4 significantly inhibited TGFbeta1-induced differentiation as measured by incorporation of alpha-SMA into stress fibers. Further, we found that
Adapala Ravi K; Thoppil Roslin J; Luther Daniel J; Paruchuri Sailaja; Meszaros J Gary; Chilian William M; Thodeti Charles K
Journal of molecular and cellular cardiology
2013
2013-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.yjmcc.2012.10.016" target="_blank" rel="noreferrer noopener">10.1016/j.yjmcc.2012.10.016</a>
Coronary collateral growth–back to the future.
Collateral Circulation/*physiology; Coronary Artery Disease/physiopathology/therapy; Coronary Circulation/physiology; Humans; Myocardial Ischemia/physiopathology/therapy; Neovascularization; Physiologic/physiology
The coronary collateral circulation is critically important as an adaptation of the heart to prevent the damage from ischemic insults. In their native state, collaterals in the heart would be classified as part of the microcirculation, existing as arterial-arterial anastomotic connections in the range of 30 to 100 muM in diameter. However, these vessels also show a propensity to remodel into components of the macrocirculation and can become arteries larger than 1000 muM in diameter. This process of outward remodeling is critically important in the adaptation of the heart to ischemia because the resistance to blood flow is inversely related to the fourth power of the diameter of the vessel. Thus, an expansion of a vessel from 100 to 1000 muM would reduce resistance (in this part of the circuit) to a negligible amount and enable delivery of flow to the region at risk. Our goal in this review is to highlight the voids in understanding this adaptation to ischemia-the growth of the coronary collateral circulation. In doing so we discuss the controversies and unknown aspects of the causal factors that stimulate growth of the collateral circulation, the role of genetics, and the role of endogenous stem and progenitor cells in the context of the normal, physiological situation and under more pathological conditions of ischemic heart disease or with some of the underlying risk factors, e.g., diabetes. The major conclusion of this review is that there are many gaps in our knowledge of coronary collateral growth and this knowledge is critical before the potential of stimulating collateralization in the hearts of patients can be realized. This article is part of a Special Issue entitled "Coronary Blood Flow".
Chilian William M; Penn Marc S; Pung Yuh Fen; Dong Feng; Mayorga Maritza; Ohanyan Vahagn; Logan Suzanna; Yin Liya
Journal of molecular and cellular cardiology
2012
2012-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.yjmcc.2011.12.006" target="_blank" rel="noreferrer noopener">10.1016/j.yjmcc.2011.12.006</a>
Vascular precursor cells in tissue injury repair.
*Wound Healing; Animals; Cell Differentiation; Cell Physiology; Cell Proliferation; Endothelium; Humans; Neovascularization; Physiologic; Regeneration – Physiology; Regeneration/*physiology; Stem Cells; Stem Cells – Physiology; Stem Cells/cytology/*physiology; Vascular/cytology; Wound Healing
Vascular precursor cells include stem cells and progenitor cells giving rise to all mature cell types in the wall of blood vessels. When tissue injury occurs, local hypoxia and inflammation result in the generation of vasculogenic mediators which orchestrate migration of vascular precursor cells from their niche environment to the site of tissue injury. The intricate crosstalk among signaling pathways coordinates vascular precursor cell proliferation and differentiation during neovascularization. Establishment of normal blood perfusion plays an essential role in the effective repair of the injured tissue. In recent years, studies on molecular mechanisms underlying the regulation of vascular precursor cell function have achieved substantial progress, which promotes exploration of vascular precursor cell-based approaches to treat chronic wounds and ischemic diseases in vital organ systems. Verification of safety and establishment of specific guidelines for the clinical application of vascular precursor cell-based therapy remain major challenges in the field.
Shi Xin; Zhang Weihong; Yin Liya; Chilian William M; Krieger Jessica; Zhang Ping
Translational research : the journal of laboratory and clinical medicine
2017
2017-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.trsl.2017.02.002" target="_blank" rel="noreferrer noopener">10.1016/j.trsl.2017.02.002</a>
Dewetting based fabrication of fibrous micro-scaffolds as potential injectable cell carriers.
Animals; Cell retention; Cells; Dewetting; Fibrous micro-constructs; Immobilized/metabolism/transplantation; Injectable constructs; Myocardial Infarction/metabolism/pathology/*therapy; Rats; Sprague-Dawley; Stem Cell Transplantation/*methods; Stem Cells/*metabolism; Tissue engineering and regeneration; Tissue Scaffolds/*chemistry
Although regenerative medicine utilizing tissue scaffolds has made enormous strides in recent years, many constraints still hamper their effectiveness. A limitation of many scaffolds is that they form surface patches, which are not particularly effective for some types of "wounds" that are deep within tissues, e.g., stroke and myocardial infarction. In this study, we reported the generation of fibrous micro-scaffolds feasible for delivering cells by injection into the tissue parenchyma. The micro-scaffolds (widths\textless100mum) were made by dewetting of poly(lactic-co-glycolic acid) thin films containing parallel strips, and cells were seeded to form cell/polymer micro-constructs during or post the micro-scaffold fabrication process. Five types of cells including rat induced vascular progenitor cells were assessed for the formation of the micro-constructs. Critical factors in forming fibrous micro-scaffolds via dewetting of polymer thin films were found to be properties of polymers and supporting substrates, temperature, and proteins in the culture medium. Also, the ability of cells to attach to the micro-scaffolds was essential in forming cell/polymer micro-constructs. Both in vitro and in vivo assessments of injecting these micro-scaffolding constructs showed, as compared to free cells, enhanced cell retention at the injected site, which could lead to improved tissue engineering and regeneration.
Song Hokyung; Yin Liya; Chilian William M; Newby Bi-Min Zhang
Materials science & engineering. C, Materials for biological applications
2015
2015-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.msec.2014.12.062" target="_blank" rel="noreferrer noopener">10.1016/j.msec.2014.12.062</a>
Epigenetic regulation in diabetes-associated oxidative stress and myocardial dysfunction.
*Epigenesis; *Oxidative Stress; Cardiomyopathies; Genetic; Humans
Yin Liya; Chilian William M; Dong Feng
International journal of cardiology
2018
2018-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.ijcard.2018.05.058" target="_blank" rel="noreferrer noopener">10.1016/j.ijcard.2018.05.058</a>
Eicosanoids in metabolic syndrome.
Adipose Tissue; Animals; Eicosanoids/*metabolism; Fatty Liver/etiology/immunology/metabolism; Humans; Immune System/immunology/metabolism; Lipid Metabolism; Metabolic Syndrome/complications/immunology/*metabolism/physiopathology; Non-alcoholic Fatty Liver Disease; Obesity/complications/immunology/metabolism; Sepsis/complications/immunology/metabolism; White/immunology/metabolism
Chronic persistent inflammation plays a significant role in disease pathology of cancer, cardiovascular disease, and metabolic syndrome (MetS). MetS is a constellation of diseases that include obesity, diabetes, hypertension, dyslipidemia, hypertriglyceridemia, and hypercholesterolemia. Nonalcoholic fatty liver disease (NAFLD) is associated with many of the MetS diseases. These metabolic derangements trigger a persistent inflammatory cascade, which includes production of lipid autacoids (eicosanoids) that recruit immune cells to the site of injury and subsequent expression of cytokines and chemokines that amplify the inflammatory response. In acute inflammation, the transcellular synthesis of antiinflammatory eicosanoids resolve inflammation, while persistent activation of the autacoid-cytokine-chemokine cascade in metabolic disease leads to chronic inflammation and accompanying tissue pathology. Many drugs targeting the eicosanoid pathways have been shown to be effective in the treatment of MetS, suggesting a common linkage between inflammation, MetS and drug metabolism. The cross-talk between inflammation and MetS seems apparent because of the growing evidence linking immune cell activation and metabolic disorders such as insulin resistance, dyslipidemia, and hypertriglyceridemia. Thus modulation of lipid metabolism through either dietary adjustment or selective drugs may become a new paradigm in the treatment of metabolic disorders. This review focuses on the mechanisms linking eicosanoid metabolism to persistent inflammation and altered lipid and carbohydrate metabolism in MetS.
Hardwick James P; Eckman Katie; Lee Yoon-Kwang; Abdelmegeed Mohamed A; Esterle Andrew; Chilian William M; Chiang John Y; Song Byoung-Joon
Advances in pharmacology (San Diego, Calif.)
2013
1905-7
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/B978-0-12-404717-4.00005-6" target="_blank" rel="noreferrer noopener">10.1016/B978-0-12-404717-4.00005-6</a>
Erratum to: Impairment of pH gradient and membrane potential mediates redox dysfunction in the mitochondria of the post-ischemic heart.
Kang Patrick T; Chen Chwen-Lih; Lin Paul; Chilian William M; Chen Yeong-Renn
Basic research in cardiology
2017
2017-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1007/s00395-017-0632-3" target="_blank" rel="noreferrer noopener">10.1007/s00395-017-0632-3</a>
Alignment of inducible vascular progenitor cells on a micro-bundle scaffold improves cardiac repair following myocardial infarction.
*Cardiovascular regeneration; *Ischemic heart diseases; *Micro-bundle scaffold; *Myocardial infarction; *Neovascularization; *Stem cells; *Tissue Scaffolds; *Vascular progenitor cells; Animal; Animals; Cell Differentiation; Cell Proliferation; Cell Survival; Cells; Coculture Techniques; Cultured; Disease Models; Endothelial Progenitor Cells/metabolism/*transplantation; Fibroblast Growth Factor 2/metabolism; Lactic Acid/*chemistry; Muscle; Myocardial Infarction/metabolism/pathology/physiopathology/*surgery; Myocardium/metabolism/*pathology; Myocytes; Paracrine Communication; Phenotype; Physiologic; Polyglycolic Acid/*chemistry; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Signal Transduction; Smooth; Smooth Muscle/metabolism/*transplantation; Sprague-Dawley; Time Factors; Tissue Engineering/*methods; Vascular Endothelial Growth Factor A/metabolism; Vascular/metabolism/*transplantation; Ventricular Remodeling
Ischemic heart disease is still the leading cause of death even with the advancement of pharmaceutical therapies and surgical procedures. Early vascularization in the ischemic heart is critical for a better outcome. Although stem cell therapy has great potential for cardiovascular regeneration, the ideal cell type and delivery method of cells have not been resolved. We tested a new approach of stem cell therapy by delivery of induced vascular progenitor cells (iVPCs) grown on polymer micro-bundle scaffolds in a rat model of myocardial infarction. iVPCs partially reprogrammed from vascular endothelial cells (ECs) had potent angiogenic potential and were able to simultaneously differentiate into vascular smooth muscle cells (SMCs) and ECs in 2D culture. Under hypoxic conditions, iVPCs also secreted angiogenic cytokines such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) as measured by enzyme-linked immunosorbent assay (ELISA). A longitudinal micro-scaffold made from poly(lactic-co-glycolic acid) was sufficient for the growth and delivery of iVPCs. Co-cultured ECs and SMCs aligned well on the micro-bundle scaffold similarly as in the vessels. 3D cell/polymer micro-bundles formed by iVPCs and micro-scaffolds were transplanted into the ischemic myocardium in a rat model of myocardial infarction (MI) with ligation of the left anterior descending artery. Our in vivo data showed that iVPCs on the micro-bundle scaffold had higher survival, and better retention and engraftment in the myocardium than free iVPCs. iVPCs on the micro-bundles promoted better cardiomyocyte survival than free iVPCs. Moreover, iVPCs and iVPC/polymer micro-bundles treatment improved cardiac function (ejection fraction and fractional shortening, endocardial systolic volume) measured by echocardiography, increased vessel density, and decreased infarction size [endocardial and epicardial infarct (scar) length] better than untreated controls at 8 weeks after MI. We conclude that iVPCs grown on a polymer micro-bundle scaffold are new promising approach for cell-based therapy designed for cardiovascular regeneration in ischemic heart disease.
Jamaiyar Anurag; Wan Weiguo; Ohanyan Vahagn; Enrick Molly; Janota Danielle; Cumpston Devan; Song Hokyung; Stevanov Kelly; Kolz Christopher L; Hakobyan Tatev; Dong Feng; Newby Bi-Min Zhang; Chilian William M; Yin Liya
Basic research in cardiology
2017
2017-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1007/s00395-017-0631-4" target="_blank" rel="noreferrer noopener">10.1007/s00395-017-0631-4</a>
Impairment of pH gradient and membrane potential mediates redox dysfunction in the mitochondria of the post-ischemic heart.
*Energy Metabolism; *Membrane potential; *Membrane Potential; *Mitochondria; *Myocardial ischemia and reperfusion; *Oxidative Stress; *pH gradient; *Redox dysfunction; Aconitate Hydratase/metabolism; Animal; Animals; Cell Line; Disease Models; Electron Transport Chain Complex Proteins/metabolism; Heart/*metabolism/pathology; Hydrogen Peroxide/metabolism; Hydrogen-Ion Concentration; Ionophores/pharmacology; Male; Mitochondria; Mitochondrial; Myocardial Infarction/*metabolism/pathology; Myocardium/*metabolism/pathology; Oxidation-Reduction; Potassium/metabolism; Rats; Sprague-Dawley; Superoxides/metabolism
The mitochondrial electrochemical gradient (Deltap), which comprises the pH gradient (DeltapH) and the membrane potential (DeltaPsi), is crucial in controlling energy transduction. During myocardial ischemia and reperfusion (IR), mitochondrial dysfunction mediates superoxide ((.)O2(-)) and H2O2 overproduction leading to oxidative injury. However, the role of DeltapH and DeltaPsi in post-ischemic injury is not fully established. Here we studied mitochondria from the risk region of rat hearts subjected to 30 min of coronary ligation and 24 h of reperfusion in vivo. In the presence of glutamate, malate and ADP, normal mitochondria (mitochondria of non-ischemic region, NR) exhibited a heightened state 3 oxygen consumption rate (OCR) and reduced (.)O2(-) and H2O2 production when compared to state 2 conditions. Oligomycin (increases DeltapH by inhibiting ATP synthase) increased (.)O2(-) and H2O2 production in normal mitochondria, but not significantly in the mitochondria of the risk region (IR mitochondria or post-ischemic mitochondria), indicating that normal mitochondrial (.)O2(-) and H2O2 generation is dependent on DeltapH and that IR impaired the DeltapH of normal mitochondria. Conversely, nigericin (dissipates DeltapH) dramatically reduced (.)O2(-) and H2O2 generation by normal mitochondria under state 4 conditions, and this nigericin quenching effect was less pronounced in IR mitochondria. Nigericin also increased mitochondrial OCR, and predisposed normal mitochondria to a more oxidized redox status assessed by increased oxidation of cyclic hydroxylamine, CM-H. IR mitochondria, although more oxidized than normal mitochondria, were not responsive to nigericin-induced CM-H oxidation, which is consistent with the result that IR induced DeltapH impairment in normal mitochondria. Valinomycin, a K(+) ionophore used to dissipate DeltaPsi, drastically diminished (.)O2(-) and H2O2 generation by normal mitochondria, but less pronounced effect on IR mitochondria under state 4 conditions, indicating that DeltaPsi also contributed to (.)O2(-) generation by normal mitochondria and that IR mediated DeltaPsi impairment. However, there was no significant difference in valinomycin-induced CM-H oxidation between normal and IR mitochondria. In conclusion, under normal conditions the proton backpressure imposed by DeltapH restricts electron flow, controls a limited amount of (.)O2(-) generation, and results in a more reduced myocardium; however, IR causes DeltapH impairment and prompts a more oxidized myocardium.
Kang Patrick T; Chen Chwen-Lih; Lin Paul; Chilian William M; Chen Yeong-Renn
Basic research in cardiology
2017
2017-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1007/s00395-017-0626-1" target="_blank" rel="noreferrer noopener">10.1007/s00395-017-0626-1</a>
Impaired coronary metabolic dilation in the metabolic syndrome is linked to mitochondrial dysfunction and mitochondrial DNA damage.
Animal; Animals; Coronary circulation; Coronary microcirculation; Coronary Vessels/metabolism/*physiopathology; Diabetes; Disease Models; DNA; DNA Damage/physiology; DNA Fragmentation; Metabolic Syndrome/metabolism/*physiopathology; Mitochondria; Mitochondria/*metabolism; Mitochondrial/*metabolism; Obesity; Oxidative Stress/physiology; Rats; Reactive Oxygen Species/metabolism; Vasodilation/physiology; Zucker
Mitochondrial dysfunction in obesity and diabetes can be caused by excessive production of free radicals, which can damage mitochondrial DNA. Because mitochondrial DNA plays a key role in the production of ATP necessary for cardiac work, we hypothesized that mitochondrial dysfunction, induced by mitochondrial DNA damage, uncouples coronary blood flow from cardiac work. Myocardial blood flow (contrast echocardiography) was measured in Zucker lean (ZLN) and obese fatty (ZOF) rats during increased cardiac metabolism (product of heart rate and arterial pressure, i.v. norepinephrine). In ZLN increased metabolism augmented coronary blood flow, but in ZOF metabolic hyperemia was attenuated. Mitochondrial respiration was impaired and ROS production was greater in ZOF than ZLN. These were associated with mitochondrial DNA (mtDNA) damage in ZOF. To determine if coronary metabolic dilation, the hyperemic response induced by heightened cardiac metabolism, is linked to mitochondrial function we introduced recombinant proteins (intravenously or intraperitoneally) in ZLN and ZOF to fragment or repair mtDNA, respectively. Repair of mtDNA damage restored mitochondrial function and metabolic dilation, and reduced ROS production in ZOF; whereas induction of mtDNA damage in ZLN reduced mitochondrial function, increased ROS production, and attenuated metabolic dilation. Adequate metabolic dilation was also associated with the extracellular release of ADP, ATP, and H2O2 by cardiac myocytes; whereas myocytes from rats with impaired dilation released only H2O2. In conclusion, our results suggest that mitochondrial function plays a seminal role in connecting myocardial blood flow to metabolism, and integrity of mtDNA is central to this process.
Guarini Giacinta; Kiyooka Takahiko; Ohanyan Vahagn; Pung Yuh Fen; Marzilli Mario; Chen Yeong-Renn; Chen Chwen-Lih; Kang Patrick T; Hardwick James P; Kolz Christopher L; Yin Liya; Wilson Glenn L; Shokolenko Inna; Dobson James G Jr; Fenton Richard; Chilian William M
Basic research in cardiology
2016
2016-05
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1007/s00395-016-0547-4" target="_blank" rel="noreferrer noopener">10.1007/s00395-016-0547-4</a>
Novel thiazolidinedione mitoNEET ligand-1 acutely improves cardiac stem cell survival under oxidative stress.
Animals; Cardiac/cytology/*drug effects; Cell Differentiation/drug effects; Flow Cytometry; Knockout; Male; Mice; Mitochondrial Membranes/metabolism; Mitochondrial Proteins/metabolism; Myocytes; Oxidative Stress/drug effects/*physiology; Rats; Real-Time Polymerase Chain Reaction; Stem Cells/cytology/*drug effects; Thiazolidinediones/*pharmacology; Zucker
Ischemic heart disease (IHD) is a leading cause of death worldwide, and regenerative therapies through exogenous stem cell delivery hold promising potential. One limitation of such therapies is the vulnerability of stem cells to the oxidative environment associated with IHD. Accordingly, manipulation of stem cell mitochondrial metabolism may be an effective strategy to improve survival of stem cells under oxidative stress. MitoNEET is a redox-sensitive, mitochondrial target of thiazolidinediones (TZDs), and influences cellular oxidative capacity. Pharmacological targeting of mitoNEET with the novel TZD, mitoNEET Ligand-1 (NL-1), improved cardiac stem cell (CSC) survival compared to vehicle (0.1% DMSO) during in vitro oxidative stress (H2O2). 10 muM NL-1 also reduced CSC maximal oxygen consumption rate (OCR) compared to vehicle. Following treatment with dexamethasone, CSC maximal OCR increased compared to baseline, but NL-1 prevented this effect. Smooth muscle alpha-actin expression increased significantly in CSC following differentiation compared to baseline, irrespective of NL-1 treatment. When CSCs were treated with glucose oxidase for 7 days, NL-1 significantly improved cell survival compared to vehicle (trypan blue exclusion). NL-1 treatment of cells isolated from mitoNEET knockout mice did not increase CSC survival with H2O2 treatment. Following intramyocardial injection of CSCs into Zucker obese fatty rats, NL-1 significantly improved CSC survival after 24 h, but not after 10 days. These data suggest that pharmacological targeting of mitoNEET with TZDs may acutely protect stem cells following transplantation into an oxidative environment. Continued treatment or manipulation of mitochondrial metabolism may be necessary to produce long-term benefits related to stem cell therapies.
Logan Suzanna J; Yin Liya; Geldenhuys Werner J; Enrick Molly K; Stevanov Kelly M; Carroll Richard T; Ohanyan Vahagn A; Kolz Christopher L; Chilian William M
Basic research in cardiology
2015
2015-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1007/s00395-015-0471-z" target="_blank" rel="noreferrer noopener">10.1007/s00395-015-0471-z</a>