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Abstract
Unlike acute myocardial infarction with reperfusion, in which infarct size is the end point reflecting irreversible injury, myocardial stunning and hibernation result from reversible myocardial ischaemia-reperfusion injury, and contractile dysfunction is the obvious end point. Stunned myocardium is characterized by a disproportionately long-lasting, yet fully reversible, contractile dysfunction that follows brief bouts of myocardial ischaemia. Reperfusion precipitates a burst of reactive oxygen species formation and alterations in excitation-contraction coupling, which interact and cause the contractile dysfunction. Hibernating myocardium is characterized by reduced regional contractile function and blood flow, which both recover after reperfusion or revascularization. Short-term myocardial hibernation is an adaptation of contractile function to the reduced blood flow such that energy and substrate metabolism recover during the ongoing ischaemia. Chronic myocardial hibernation is characterized by severe morphological alterations and altered expression of metabolic and pro-survival proteins. Myocardial stunning is observed clinically and must be recognized but is rarely haemodynamically compromising and does not require treatment. Myocardial hibernation is clinically identified with the use of imaging techniques, and the myocardium recovers after revascularization. Several trials in the past two decades have challenged the superiority of revascularization over medical therapy for symptomatic relief and prognosis in patients with chronic coronary syndromes. A better understanding of the pathophysiology of myocardial stunning and hibernation is important for a more precise indication of revascularization and its consequences. Therefore, this Review summarizes the current knowledge of the pathophysiology of these characteristic reperfusion phenomena and highlights their clinical implications.
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2
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Tyrosine nitration of mitochondrial proteins during myocardial ischemia and reperfusion. J Physiol Biochem 2019; 75:217-227. [PMID: 31115776 DOI: 10.1007/s13105-019-00683-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 04/23/2019] [Indexed: 12/28/2022]
Abstract
Myocardial ischemia reperfusion is associated with mitochondrial dysfunction and increased formation of reactive oxygen/nitrogen species. The main purpose of this study was to assess the role of tyrosine nitration of mitochondrial proteins in postischemic contractile dysfunction known as myocardial stunning. Isolated Langendorff-perfused rat hearts were subjected to 20-min global ischemia followed by 30-min reperfusion. The reperfused hearts showed marked decline in left ventricular developed pressure, maximal rate of contraction (+dP/dt), and maximal rate of relaxation (-dP/dt). Immunofluorescence and ELISA assays demonstrated enhanced protein tyrosine nitration in reperfused hearts. Using two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry, eight mitochondrial proteins were identified to be nitrated after ischemia reperfusion. These proteins are crucial in mitochondrial electron transport, fatty acid oxidation, tricarboxylic acid cycle, ATP synthesis, and control of high-energy phosphates. The proteome data also indicated reduced abundance in several of nitrated proteins. The results suggest that these changes may contribute to inhibition of aconitase activity but are unlikely to affect electron transport chain activity. Whether tyrosine nitration of mitochondrial proteins can be considered the contributing factor of postischemic contractile dysfunction remains to be explored.
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3
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Guaricci AI, Bulzis G, Pontone G, Scicchitano P, Carbonara R, Rabbat M, De Santis D, Ciccone MM. Current interpretation of myocardial stunning. Trends Cardiovasc Med 2017; 28:263-271. [PMID: 29221768 DOI: 10.1016/j.tcm.2017.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 11/16/2017] [Accepted: 11/19/2017] [Indexed: 12/11/2022]
Abstract
Myocardial stunning is a temporary post-ischemic cardiac mechanical dysfunction. As such, it is a heterogeneous entity and different conditions can promote its occurrence. Transient coronary occlusion, increased production of catecholamines and endothelin, and myocardial inflammation are all possible causes of myocardial stunning. Possible underlying mechanisms include an oxyradical hypothesis, calcium overload, decreased responsiveness of myofilaments to calcium, and excitation-contraction uncoupling due to sarcoplasmic reticulum dysfunction. The aim of this review is to summarize the clinical conditions that may be responsible for stunned myocardium.
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Affiliation(s)
- Andrea Igoren Guaricci
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy; Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy.
| | - Gabriella Bulzis
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy
| | | | | | - Rossella Carbonara
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy
| | - Mark Rabbat
- Loyola University of Chicago, Chicago, IL; Edward Hines Jr. VA Hospital, Hines, IL
| | - Delia De Santis
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy
| | - Marco Matteo Ciccone
- Institute of Cardiovascular Disease, Department of Emergency and Organ Transplantation, University Hospital "Policlinico" of Bari, Bari, Italy
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4
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DEBOLD EDWARDP, FITTS ROBERTH, SUNDBERG CHRISTOPHERW, NOSEK THOMASM. Muscle Fatigue from the Perspective of a Single Crossbridge. Med Sci Sports Exerc 2016; 48:2270-2280. [DOI: 10.1249/mss.0000000000001047] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Woodward M, Previs MJ, Mader TJ, Debold EP. Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model. Front Physiol 2015; 6:199. [PMID: 26236240 PMCID: PMC4503891 DOI: 10.3389/fphys.2015.00199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 06/29/2015] [Indexed: 12/27/2022] Open
Abstract
Cardiac arrest is a prevalent condition with a poor prognosis, attributable in part to persistent myocardial dysfunction following resuscitation. The molecular basis of this dysfunction remains unclear. We induced cardiac arrest in a porcine model of acute sudden death and assessed the impact of ischemia and reperfusion on the molecular function of isolated cardiac contractile proteins. Cardiac arrest was electrically induced, left untreated for 12 min, and followed by a resuscitation protocol. With successful resuscitations, the heart was reperfused for 2 h (IR2) and the muscle harvested. In failed resuscitations, tissue samples were taken following the failed efforts (IDNR). Actin filament velocity, using myosin isolated from IR2 or IDNR cardiac tissue, was nearly identical to myosin from the control tissue in a motility assay. However, both maximal velocity (25% faster than control) and calcium sensitivity (pCa50 6.57 ± 0.04 IDNR vs. 6.34 ± 0.07 control) were significantly (p < 0.05) enhanced using native thin filaments (actin+troponin+tropomyosin) from IDNR samples, suggesting that the enhanced velocity is mediated through an alteration in muscle regulatory proteins (troponin+tropomyosin). Mass spectrometry analysis showed that only samples from the IR2 had an increase in total phosphorylation levels of troponin (Tn) and tropomyosin (Tm), but both IR2 and IDNR samples demonstrated a significant shift from mono-phosphorylated to bis-phosphorylated forms of the inhibitory subunit of Tn (TnI) compared to control. This suggests that the shift to bis-phosphorylation of TnI is associated with the enhanced function in IDNR, but this effect may be attenuated when phosphorylation of Tm is increased in tandem, as observed for IR2. There are likely many other molecular changes induced following cardiac arrest, but to our knowledge, these data provide the first evidence that this form cardiac arrest can alter the in vitro function of the cardiac contractile proteins.
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Affiliation(s)
- Mike Woodward
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, MA, USA
| | - Michael J Previs
- Department of Molecular Physiology and Biophysics, University of Vermont Burlington, VT, USA
| | - Timothy J Mader
- Department of Emergency Medicine, Baystate Medical Center/Tufts University School of Medicine Springfield, MA, USA
| | - Edward P Debold
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, MA, USA ; Muscle Biophysics Lab, Department of Kinesiology, University of Massachusetts Amherst, MA, USA
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6
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The effects of α- and β-adrenergic blocking agents on postresuscitation myocardial dysfunction and myocardial tissue injury in a rat model of cardiac arrest. Transl Res 2015; 165:589-98. [PMID: 25468485 DOI: 10.1016/j.trsl.2014.10.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 12/21/2022]
Abstract
We investigated the relationship between the severity of postresuscitation (PR) myocardial tissue injury and myocardial dysfunction after the administration of epinephrine as well as the protective effects of α- and β-adrenergic blocking agents. Forty male Sprague-Dawley rats were randomized into 6 groups: (1) placebo; (2) epinephrine; (3) epinephrine pretreated with α1-blocker (prazosin); (4) epinephrine pretreated with α2-blocker (yohimbine); (5) epinephrine pretreated with β-blocker (propranolol); and (6) epinephrine pretreated with β- plus α1-blocker (propranolol and prazosin). Cardiopulmonary resuscitation was initiated after 8 minutes of untreated ventricular fibrillation and continued for an additional 8 minutes. The myocardial function and the serum concentrations of troponin I (Tn I) and N-terminal probrain natriuretic peptide (NT-proBNP) were measured at baseline and after resuscitation. After resuscitation, both Tn I and NT-proBNP were significantly increased in all groups, especially in the epinephrine and epinephrine pretreated with α2-blocker groups. Significantly better PR myocardial function and neurologic deficit score were observed in epinephrine pretreated with the α1- or β-blocker with decreased releases of Tn I and NT-proBNP. However, the most significant improvements were observed in the animals pretreated with β- plus α1-blocker. The present study demonstrated that myocardial stunning may not be the only mechanism of PR myocardial dysfunction. Administration of epinephrine increased the severity of PR myocardial tissue injury and dysfunction. The β- and β- plus α1-blocker pretreatment significantly reduced the severity of PR myocardial tissue injury and myocardial dysfunction with better neurologic function and prolonged duration of survival.
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7
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Wijnker PJM, Li Y, Zhang P, Foster DB, dos Remedios C, Van Eyk JE, Stienen GJM, Murphy AM, van der Velden J. A novel phosphorylation site, Serine 199, in the C-terminus of cardiac troponin I regulates calcium sensitivity and susceptibility to calpain-induced proteolysis. J Mol Cell Cardiol 2015; 82:93-103. [PMID: 25771144 DOI: 10.1016/j.yjmcc.2015.03.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 12/28/2022]
Abstract
Phosphorylation of cardiac troponin I (cTnI) by protein kinase C (PKC) is implicated in cardiac dysfunction. Recently, Serine 199 (Ser199) was identified as a target for PKC phosphorylation and increased Ser199 phosphorylation occurs in end-stage failing compared with non-failing human myocardium. The functional consequences of cTnI-Ser199 phosphorylation in the heart are unknown. Therefore, we investigated the impact of phosphorylation of cTnI-Ser199 on myofilament function in human cardiac tissue and the susceptibility of cTnI to proteolysis. cTnI-Ser199 was replaced by aspartic acid (199D) or alanine (199A) to mimic phosphorylation and dephosphorylation, respectively, with recombinant wild-type (Wt) cTn as a negative control. Force development was measured at various [Ca(2+)] and at sarcomere lengths of 1.8 and 2.2 μm in demembranated cardiomyocytes in which endogenous cTn complex was exchanged with the recombinant human cTn complexes. In idiopathic dilated cardiomyopathy samples, myofilament Ca(2+)-sensitivity (pCa50) at 2.2 μm was significantly higher in 199D (pCa50 = 5.79 ± 0.01) compared to 199A (pCa50 = 5.65 ± 0.01) and Wt (pCa50 = 5.66 ± 0.02) at ~63% cTn exchange. Myofilament Ca(2+)-sensitivity was significantly higher even with only 5.9 ± 2.5% 199D exchange compared to 199A, and saturated at 12.3 ± 2.6% 199D exchange. Ser199 pseudo-phosphorylation decreased cTnI binding to both actin and actin-tropomyosin. Moreover, altered susceptibility of cTnI to proteolysis by calpain I was found when Ser199 was pseudo-phosphorylated. Our data demonstrate that low levels of cTnI-Ser199 pseudo-phosphorylation (~6%) increase myofilament Ca(2+)-sensitivity in human cardiomyocytes, most likely by decreasing the binding affinity of cTnI for actin-tropomyosin. In addition, cTnI-Ser199 pseudo-phosphorylation or mutation regulates calpain I mediated proteolysis of cTnI.
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Affiliation(s)
- Paul J M Wijnker
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands; Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands.
| | - Yuejin Li
- Department of Pediatrics, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Pingbo Zhang
- Department of Pediatrics, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - D Brian Foster
- Department of Pediatrics, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Cris dos Remedios
- Muscle Research Unit, Bosch Institute, The University of Sydney, Sydney, Australia
| | - Jennifer E Van Eyk
- The Advanced Clinical Biosystems Research Institute, The Heart Institute, Department of Medicine, Cedars Sinai Medical Center, Los Angeles, CA, USA
| | - Ger J M Stienen
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands; Department of Physics and Astronomy, VU University, Amsterdam, The Netherlands
| | - Anne M Murphy
- Department of Pediatrics, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands; ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
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Muscari C, Capanni C, Giordano E, Stefanelli C, Bonavita F, Stanic I, Bonafè F, Caldarera CM, Guarnieri C. Leupeptin Preserves Cardiac Nitric Oxide Synthase 3 During Reperfusion Following Long-Term Cardioplegia. J Surg Res 2010; 164:e27-35. [DOI: 10.1016/j.jss.2010.05.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 05/05/2010] [Accepted: 05/17/2010] [Indexed: 11/27/2022]
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9
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Beiser DG, Orbelyan GA, Inouye BT, Costakis JG, Hamann KJ, McNally EM, Vanden Hoek TL. Genetic deletion of NOS3 increases lethal cardiac dysfunction following mouse cardiac arrest. Resuscitation 2010; 82:115-21. [PMID: 20951489 DOI: 10.1016/j.resuscitation.2010.08.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 08/23/2010] [Accepted: 08/30/2010] [Indexed: 12/23/2022]
Abstract
STUDY AIMS Cardiac arrest mortality is significantly affected by failure to obtain return of spontaneous circulation (ROSC) despite cardiopulmonary resuscitation (CPR). Severe myocardial dysfunction and cardiovascular collapse further affects mortality within hours of initial ROSC. Recent work suggests that enhancement of nitric oxide (NO) signaling within minutes of CPR can improve myocardial function and survival. We studied the role of NO signaling on cardiovascular outcomes following cardiac arrest and resuscitation using endothelial NO synthase knockout (NOS3(-/-)) mice. METHODS Adult female wild-type (WT) and NOS3(-/-) mice were anesthetized, intubated, and instrumented with left-ventricular pressure-volume catheters. Cardiac arrest was induced with intravenous potassium chloride. CPR was performed after 8min of untreated arrest. ROSC rate, cardiac function, whole-blood nitrosylhemoglobin (HbNO) concentrations, heart NOS3 content and phosphorylation (p-NOS3), cyclic guanosine monophosphate (cGMP), and phospho-troponin I (p-TnI) were measured. RESULTS Despite equal quality CPR, NOS3(-/-) mice displayed lower rates of ROSC compared to WT (47.6% [10/21] vs. 82.4% [14/17], p<0.005). Among ROSC animals, NOS3(-/-) vs. WT mice exhibited increased left-ventricular dysfunction and 120min mortality. Prior to ROSC, myocardial effectors of NO signaling including cGMP and p-TnI were decreased in NOS3(-/-) vs. WT mice (p<0.05). Following ROSC in WT mice, significant NOS3-dependent increases in circulating HbNO were seen by 120min. Significant increases in cardiac p-NOS3 occurred between end-arrest and 15min post-ROSC, while total NOS3 content was increased by 120min post-ROSC (p<0.05). CONCLUSIONS Genetic deletion of NOS3 decreases ROSC rate and worsens post-ROSC left-ventricular function. Poor cardiovascular outcomes are associated with differences in NOS3-dependent myocardial cGMP signaling and circulating NO metabolites.
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Affiliation(s)
- David G Beiser
- Emergency Resuscitation Center, Section of Emergency Medicine, University of Chicago, 5841 S. Maryland Ave., MC 5068, Chicago, IL 60637, USA.
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10
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Lin Y, Fu Q, Zhu J, Miller JM, Van Eyk JE. Development of a Qualitative Sequential Immunoassay for Characterizing the Intrinsic Properties of Circulating Cardiac Troponin I. Clin Chem 2010; 56:1307-19. [DOI: 10.1373/clinchem.2009.135186] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND
With myocardial infarction (MI), cardiac troponin is released from the heart into circulation, where it can be detected with immunoassays independently quantifying cardiac troponin I (cTnI) or cTnT. There is, however, no single immunoassay that sequentially probes the posttranslational modification status of cTnI or directly characterizes whether circulating cTnI is bound to cTnC and/or cTnT. Here we describe the development of a qualitative immunoassay to directly probe the primary and ternary structure of circulating cTnI through diffractive optics technology (dotLab® System, Axela).
METHODS
Anti-cTnI antibody 8I-7 was immobilized on a patterned sensor to capture cTnI. One or more detector antibodies were sequentially introduced to probe for amino acid sequence integrity or phosphorylation status of cTnI, or its association with cTnC and/or cTnT. Respective immunocaptures were recorded as real-time diffractive intensities (DIs), and the DI differences were analyzed. Each immunodetection was independent of the others but was done in a single sequential assay.
RESULTS
This diffraction-based immunoassay successfully characterized cTnI. The unamplified assay determined whether cTnI was degraded at N-terminus and/or C-terminus or phosphorylated. Sequential application of multiple detector antibodies without an antibody-stripping step enables real-time interrogation of 5 different epitopes of cTnI, or direct detection of the cTn complex (cTnI–cTnC–cTnT) in a single sequential assay. Finally, this assay was optimized with amplification to directly detect circulating cTnI bound to cTnC and cTnT in serum from an MI patient.
CONCLUSIONS
The dot® Immunoassay is the first qualitative sequential immunoassay to address the direct interactions of the troponin subunits and various modified forms of cTnI.
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Affiliation(s)
- Yixin Lin
- Axela Inc., Toronto, Ontario, Canada
| | - Qin Fu
- Department of Medicine and
| | | | | | - Jennifer E Van Eyk
- Department of Medicine and
- Departments of Biological Chemistry and Biomedical Engineering and Johns Hopkins Bayview Proteomics Center, Johns Hopkins University, Baltimore, MD
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11
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Abstract
This review briefly synthesizes the molecular biology of troponin, which is currently the best biochemical marker for the detection of cardiac injury and, thus, acute myocardial infarction as well. Potential new uses for the marker based on these insights, with a specific interest in cardiac troponin fragments that potentially could be linked to distinct clinical conditions, are described. Some of the clinical problems clinicians are faced with including how to use the markers in renal failure and the difficulties associated with the heterogeneity of current troponin assays are also discussed. Finally, we present the possibility of specific cardiac troponin fragments resulting from modification or degradation, associated with distinct pathological processes, as new potential uses for this biomarker.
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Affiliation(s)
- Vlad C Vasile
- Mayo Clinic & Mayo Medical School, Department of Internal Medicine, Division of Cardiovascular Diseases & Department of Laboratory Medicine & Pathology, Rochester, Minnesota, USA
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12
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Garcia SC, Pomblum VJ, Gams E, Rupp H, Schipke JD. Reduction in β-myosin heavy chains in stunned myocardium as assessed by nondenaturing gel electrophoresis. Pflugers Arch 2007; 454:937-43. [PMID: 17503071 DOI: 10.1007/s00424-007-0268-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 04/12/2007] [Indexed: 11/28/2022]
Abstract
Myosin plays a key role in the structure and function of cardiac muscle. Three myosin isoenzymes (V(1), V(2), and V(3)) with different ATPase activities have been identified in mammalian ventricles based on their heavy chain constituents. The relative amount of myosin isoenzymes changes under physiological and pathological conditions. Until now, myosin isoenzymes have frequently been determined using either tube gel (nondenaturing) polyacrylamide gel electrophoresis (PAGE), or gradient or uniform sodium dodecyl sulfate (denaturing) PAGE. Both methods have disadvantages, e.g., a long running time. We developed, therefore, a uniform, nondenaturing PAGE with slab minigel format for analyzing the myosin isoenzymes in normoxic and stunned rabbit hearts. In normoxic hearts of adult rabbits, V(3) predominated over V(1) (46 vs 41%). In turn, in the stunned hearts, V(1) predominated over V(3) (70 vs 30%), and the heterodimeric V(2) was not anymore detectable. This alteration appears to result from a selective loss of myosin heavy chain (MHC)-beta. In parallel, the biochemical markers troponin I and creatine kinase were increased in the stunned hearts. We suggest that alterations of myosin isoenzymes in stunned myocardium can be monitored with native PAGE. The present analysis of myosin isoenzyme appears thus as a new tool for evaluating defects in MHC dimer formation in postischemic hearts.
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Affiliation(s)
- S C Garcia
- Department of Surgery I, University Hospital Duesseldorf, Heinrich-Heine-University, Moorenstrasse 5, 40225, Duesseldorf, Germany.
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13
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Yuan C, Guo Y, Ravi R, Przyklenk K, Shilkofski N, Diez R, Cole RN, Murphy AM. Myosin binding protein C is differentially phosphorylated upon myocardial stunning in canine and rat hearts — Evidence for novel phosphorylation sites. Proteomics 2006; 6:4176-86. [PMID: 16791825 DOI: 10.1002/pmic.200500894] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Myocardial stunning is the transient cardiac dysfunction that follows brief episodes of ischemia and reperfusion without associated myocardial necrosis. Currently, there is limited knowledge about its cellular and biochemical mechanisms. In order to better understand the underlying mechanisms of contractile dysfunction associated with the stunning, comprehensive proteomic studies using 2-D DIGE were performed using a regional stunning model in canine heart. Cardiac myosin binding protein C (cMyBP-C), a regulatory myofilament protein associated with the thick filament, and nebulette, a thin filament associated protein, were differentially expressed. Phosphoprotein specific staining indicated both protein changes were due to phosphorylation. Subsequent phosphorylation mapping of canine cMyBP-C using IMAC and MS/MS identified five phosphorylation sites, including three novel sites. In order to further evaluate this finding in a different model, cMyBP-C phosphorylation was examined in a rat model of global stunning. In the rat model, stunning was associated with increased phosphorylation of cMyBP-C at a critical calcium/calmodulin-dependent kinase II site, and the increased phosphorylation was largely inhibited when stunning was prevented by either ischemic preconditioning or reperfusion in the presence of low-calcium buffer. These data indicate cMyBP-C phosphorylation plays an important role in myocardial stunning.
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Affiliation(s)
- Chao Yuan
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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14
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Hall SRR, Wang L, Milne B, Hong M. Mannitol but not dantrolene prevents myocardial dysfunction following intra-cranial hypertension in rats. Am J Transplant 2005; 5:2862-9. [PMID: 16302998 DOI: 10.1111/j.1600-6143.2005.01127.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Cardiac complications stemming from intra-cranial hypertension may result from impaired intra-cellular Ca(2+) homeostasis. The aim of this study was to examine the effects of dantrolene, a blocker of sarcoplasmic reticulum (SR) Ca(2+) release, on myocardial dysfunction associated with intra-cranial hypertension in rats. Dantrolene (10 mg) with and without 15% mannitol was administered to halothane-anesthetized rats prior to induction of intra-cranial hypertension by subdural balloon inflation. Its effects were compared to 3% and 15% mannitol and 5% Pentaspan. Dantrolene with mannitol or 15% mannitol alone prevented the transient intra-cranial hypertension-induced hyperdynamic response and ensuing circulatory collapse that was found in animals pre-treated with 3% mannitol solution or pentaspan. Moreover, hemodynamic function was preserved irrespective of TnI cleavage. However, only animals treated with high dose 15% mannitol exhibited lower lipid peroxidation content in the heart. In contrast, pre-treatment with dantrolene alone did not prevent the cardiac complications associated with intra-cranial hypertension. In conclusion, 15% mannitol attenuated the cardiopulmonary complications associated with intra-cranial hypertension. Dantrolene without mannitol was without effect. Since mannitol exhibits free radical scavenging properties, protection could be the result of a decrease in oxidative stress after intra-cranial hypertension.
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Affiliation(s)
- S R R Hall
- Department of Anesthesiology, Queen's University, Kingston, Ontario, Canada
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15
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Powell SR, Wang P, Katzeff H, Shringarpure R, Teoh C, Khaliulin I, Das DK, Davies KJA, Schwalb H. Oxidized and ubiquitinated proteins may predict recovery of postischemic cardiac function: essential role of the proteasome. Antioxid Redox Signal 2005; 7:538-46. [PMID: 15889999 DOI: 10.1089/ars.2005.7.538] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This study examined the hypothesis that postischemic levels of oxidized and/or ubiquitinated proteins may be predictive of functional recovery as they may be indicative of activity of the 20S and/or 26S proteasomes, respectively. Subjecting isolated rat hearts to 15 min of ischemia had no effect on 20S- and 26S-proteasome activities; however, both were significantly (p < 0.05) decreased by 70% and 54%, respectively, following 30 min of ischemia and 60 min of reperfusion, changes associated with increased levels of protein carbonyls and ubiquitinated proteins. Preischemic treatment of hearts with the proteasome inhibitor, MG132, resulted in dose-dependent decreases (p < 0.05) in recovery of postischemic function [MG132 (microM), heart rate x pressure product: 0, 11,158 +/- 2,423; 6, 11,400 +/- 3,009; 12, 5,513 +/- 2,225; 25, 2,325 +/- 992] and increased accumulation of ubiquitinated proteins. Preconditioning with repetitive ischemia (IP) or preischemic treatment with nicorandil (Nic) resulted in a significant increase in postischemic 20S-proteasome activity after 60 min of reperfusion (control, 95 +/- 4; IP, 301 +/- 65; Nic, 242 +/- 61 fluorescence units). Only Nic had similar effects on 26S-proteasome activity. These results support the conclusion that a correlation exists between eventual recovery of postischemic function and levels of oxidized and/or ubiquitinated proteins, a phenomenon that may be dependent on activity of the 20S and 26S proteasomes.
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Affiliation(s)
- Saul R Powell
- Department of Medicine, Long Island Jewish Medical Center Campus of the Albert Einstein College of Medicine, New Hyde Park, NY 11042, USA.
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16
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McDonough JL, Van Eyk JE. Developing the next generation of cardiac markers: Disease-induced modifications of troponin I. Prog Cardiovasc Dis 2004; 47:207-16. [PMID: 15736586 DOI: 10.1016/j.pcad.2004.07.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Troponin I (TnI) and Troponin T (TnT) have evolved into arguably the two most important diagnostic markers for acute myocardial injury. Part of their diagnostic utility lies in the uniquely important roles that both TnI and TnT play in the calcium-dependent regulation of cardiac muscle contraction. Both proteins undergo extensive physiologic regulation, principally through phosphorylation, as well as specific disease-induced pathologic modifications, including phosphorylation, oxidation, and proteolysis. Many, if not all, of these protein modifications in some way modulate contractility, and when detected in serum may therefore provide important information about both the disease state and functional status of the heart. However, the complexity of the TnI (and TnT) forms in the serum is large, which leads to difficulty in detecting all of the Tn subunits in serum, and hence interpreting the biologic significance of each modified product. But, as diagnostic tools and modalities improve, our ability to monitor and detect specific disease-induced modified forms of proteins will inevitably lead to better and more specific diagnoses and therapies.
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Affiliation(s)
- Jason L McDonough
- Department of Medicine, The Johns Hopkins University, 602 Mason F. Lord Bldg., Center Tower, Baltimore MD 21224, USA
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Sprung J, West AJ, Bacon DR, Burkle CM, Bourke DL. Myocardial stunning during abdominal hysterectomy in a healthy woman. J Clin Anesth 2003; 15:537-9. [PMID: 14698368 DOI: 10.1016/j.jclinane.2003.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We report a case of myocardial stunning in a healthy patient. During gynecologic surgery, two brief episodes of asystole occurred. Following resuscitation there was a short period of severe hypertension and tachycardia. Electrocardiographic changes and elevations in troponin T and creatine-kinase-MB were observed. Angiography revealed normal coronary arteries and multiple areas of hypokinesis. Within 2 weeks, all abnormal values had returned to normal and the patient underwent an uneventful surgery.
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Affiliation(s)
- Juraj Sprung
- Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA
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Dos Remedios CG, Liew CC, Allen PD, Winslow RL, Van Eyk JE, Dunn MJ. Genomics, proteomics and bioinformatics of human heart failure. J Muscle Res Cell Motil 2003; 24:251-60. [PMID: 14620738 PMCID: PMC1351347 DOI: 10.1023/a:1025433721505] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Unraveling the molecular complexities of human heart failure, particularly end-stage failure, can be achieved by combining multiple investigative approaches. There are several parts to the problem. Each patient is the product of a complex set of genetic variations, different degrees of influence of diets and lifestyles, and usually heart transplantation patients are treated with multiple drugs. The genomic status of the myocardium of any one transplant patient can be analysed using gene arrays (cDNA- or oligonucleotide-based) each with its own strengths and weaknesses. The proteins expressed by these failing hearts (myocardial proteomics) were first investigated over a decade ago using two-dimensional polyacrylamide gel electrophoresis (2DGE) which promised to resolve several thousand proteins in a single sample of failing heart. However, while 2DGE is very successful for the abundant and moderately expressed proteins, it struggles to identify proteins expressed at low levels. Highly focused first dimension separations combined with recent advances in mass spectrometry now provide new hope for solving this difficulty. Protein arrays are a more recent form of proteomics that hold great promise but, like the above methods, they have their own drawbacks. Our approach to solving the problems inherent in the genomics and proteomics of heart failure is to provide experts in each analytical method with a sample from the same human failing heart. This requires a sufficiently large number of samples from a sufficiently large pool of heart transplant patients as well as a large pool of non-diseased, non-failing human hearts. We have collected more than 200 hearts from patients undergoing heart transplantations and a further 50 non-failing hearts. By combining our expertise we expect to reduce and possibly eliminate the inherent difficulties of each analytical approach. Finally, we recognise the need for bioinformatics to make sense of the large quantities of data that will flow from our laboratories. Thus, we plan to provide meaningful molecular descriptions of a number of different conditions that result in terminal heart failure.
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Affiliation(s)
- C G Dos Remedios
- Muscle Research Unit, Institute for Biomedical Research, University of Sydney, Sydney 2006, Australia.
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Jäger D, Jungblut PR, Müller-Werdan U. Separation and identification of human heart proteins. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 771:131-53. [PMID: 12015996 DOI: 10.1016/s1570-0232(02)00039-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Heart failure is not a uniform disease entity, but a syndrome with various causes, including hypertension, ischemia and congenital heart disease, cardiomyopathy, myocarditis and intoxication. During the recent years a number of molecular and cellular alterations have been identified in the diseased heart, but a direct causative link between these changes and functional impairment, medical responsiveness, progression of the disease and the patients' outcome remains to be established. After an accumulation of large amounts of DNA sequence data in genomic projects, scientists have now turned their attention to the central executors of all programs of life, the proteins. In complementation of the genomic initiatives, proteomics based approaches have lined up not only for large-scale identification of proteins and their post-translational modifications, but also to study the function of protein complexes, protein-protein interactions and regulatory and signalling cascades in the cellular network. In concert with genomic data functional proteomics will hold the key for a better understanding and therapeutical management of cardiovascular diseases in the future.
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Affiliation(s)
- D Jäger
- Department of Medicine III, Martin-Luther University, Halle-Wittenberg, Germany.
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