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Wachtfogel YT, Bischoff R, Bauer R, Hack CE, Nuijens JH, Kucich U, Niewiarowski S, Edmunds LH, Colman RW. α1-Antitrypsin Pittsburgh (Met358 → Arg) Inhibits the Contact Pathway of Intrinsic Coagulation and Alters the Release of Human Neutrophil Elastase during Simulated Extracorporeal Circulation. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1648972] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryCardiopulmonary bypass prolongs bleeding time, increases postoperative blood loss, and triggers activation of plasma proteolytic enzyme systems and blood cells referred to as the “whole body inflammatory response”. Contact of blood with synthetic surfaces leads to qualitative and quantitative alterations in platelets, neutrophils, contact and complement systems. Contact and complement pathway proteins both induce neutrophil activation, a j-antitrypsin Pittsburgh (Met358 → Arg), a mutant of α1-antitrypsin, is a potent inhibitor of plasma kalli-krein and thrombin. We investigated whether this recombinant mutant protein inhibited platelet activation, as well as contact and/or complement-induced neutrophil activation during simulated extracorporeal circulation.Arg358 α1-antitrypsin did not prevent the 34% drop in platelet count at 5 min of recirculation, did not block the 50% decrease in ADP-induced platelet aggregation at 120 min of recirculation, nor inhibit the release of 6.06 α 1.07 µg/ml (3-thromboglobulin at 120 min of recirculation suggesting that the inhibitor had little effect on platelet activation. However, Arg358 α1 arantitrypsin totally blocked kallikrein-Cl-in-hibitor complex formation but not Cl-Cl-inhibitor complex formation. Most importantly, Arg358 α1-antitrypsin decreased the release of 1.11 α 0.16 µg/ml human neutrophil elastase by 43%. The attenuation of neutrophil activation in the absence of an effect on complement activation via the classical pathway, supports the concept that kallikrein is a major mediator of neutrophil degranulation during cardiopulmonary bypass.
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Affiliation(s)
- Yanina T Wachtfogel
- Sol Sherry Thrombosis Research Center and the Hematology Division, Departments of Medicine and Physiology, Temple University School of Medicine, Philadelphia, PA, USA
| | | | - Ross Bauer
- Division of Cardiothoracic Surgery, Harrison Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - C Erik Hack
- Central Laboratory of The Netherlands Red Cross, Blood Transfusion Service and Laboratory for Experimental and Clinical Immunology, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Umberto Kucich
- Research Division, Department of Medicine, The Graduate Hospital, Philadelphia, PA, USA
| | - Stefan Niewiarowski
- Sol Sherry Thrombosis Research Center and the Hematology Division, Departments of Medicine and Physiology, Temple University School of Medicine, Philadelphia, PA, USA
| | - L Henry Edmunds
- Division of Cardiothoracic Surgery, Harrison Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Robert W Colman
- Sol Sherry Thrombosis Research Center and the Hematology Division, Departments of Medicine and Physiology, Temple University School of Medicine, Philadelphia, PA, USA
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Sundaram S, Gikakis N, Erik Hack C, Niewiarowski S, Edmunds LH, Koneti Rao A, Sun L, Cooper SL, Colman RW. Nafamostat Mesilate, a Broad Spectrum Protease Inhibitor, Modulates Platelet, Neutrophil and Contact Activation in Simulated Extracorporeal Circulation. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1650224] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryActivation of humoral and cellular participants in inflammation enhances the risk of postoperative bleeding and multiple organ damage in cardiopulmonary bypass (CPB). We now compare the effects of heparin alone in combination with nafamostat mesilate (NM), a protease inhibitor with specificity of trypsin-like enzymes, in an extracorporeal circuit which simulates CPB. NM significantly inhibits the release of platelet (β-thromboglobulin (βTG) at 60 and 120 min. Platelet counts do not differ. ADP-induced aggregation decreases in circuits with NM, which is due to a direct effect of NM on platelet function. NM prevents any significant release of neutrophil elastase; at 120 min, plasma elastase-α1antitrypsin complex is 0.16 μg/ml in the NM group and 1.24 μg/ml in the control group. NM completely inhibits formation of complexes of C1 inhibitor with kallikrein and FXIIa. NM does not alter markers of complement activation (C1-C1-inhibitor complex and C5b-9), or indicators of thrombin formation (F1.2). However, at 120 min, thrombin activity as measured by release of fibrinopeptide A is significantly decreased. The data indicate that complement activation during CPB correlates poorly with neutrophil activation and that either kallikrein or FXIIa or both may be more important agonists. The ability of NM to inhibit two important contact system proteins and platelet and neutrophil release raises the possibility of suppressing the inflammatory response during clinical CPB.
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Affiliation(s)
- Sumuk Sundaram
- The Department of Chemical Engineering, University of Delaware, Newark, DE, USA
| | - Nicolas Gikakis
- The Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - C Erik Hack
- The Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam, The Netherlands
| | - Stefan Niewiarowski
- The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - L H Edmunds
- The Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - A Koneti Rao
- The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, USA
| | - Ling Sun
- The Department of Chemical Engineering, University of Delaware, Newark, DE, USA
| | - S L Cooper
- The Department of Chemical Engineering, University of Delaware, Newark, DE, USA
| | - Robert W Colman
- The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, USA
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Sun L, Hiramatsu Y, Gorman JH, Edmunds LH, Rao AK. Glycoprotein IIb/IIIa Receptor Antagonist Tirofiban Inhibits Thrombin Generation during Cardiopulmonary Bypass in Baboons. Thromb Haemost 2017. [DOI: 10.1055/s-0037-1614643] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
SummaryPlatelets play a major role in coagulation mechanisms and anti-GPIIb-IIIa antibodies inhibit tissue-factor induced thrombin generation in in vitro studies. Tirofiban, a nonpeptide selective glycoprotein (GP) IIb/IIIa antagonist, preserves platelet number and function during cardiopulmonary bypass (CPB) in baboons. We tested the hypothesis that platelet inhibition by tirofiban inhibits thrombin generation in vivo. Four groups of baboons (n = 7-12) were perfused for 60 min; all groups received heparin (300 units/kg). The controls received only heparin. The low dose (0.1 μg/kg/min) and high dose (0.3 μg/kg/min) infusion groups received tirofiban for 60 min before and 60 min during CPB. The bolus plus low dose infusion group received a 15 μg/kg bolus before starting CPB and a low dose infusion (0.1 mg/kg/min) only during CPB. At end of CPB, compared to control group (2.99 ± 0.36 nM), prothrombin fragment F1.2 levels were lower (p <0.05) in low dose infusion group (1.65 ± 0.14 nM, mean ± SE) and high dose infusion group (1.71 ± 0.19 nM), but not bolus plus infusion group (2.69 ± 0.49 nM); they remained significantly lower after protamine administration. At end of CPB, thrombin-antithrombin complex levels were lower in high dose infusion group (40.0 ± 11.2 ng/ml, p <0.05) compared to control group (76.2 ± 7.3 ng/ml). These studies indicate that tirofiban inhibits not only platelet aggregation but also thrombin generation in vivo during CPB, and that this effect is demonstrable even in the presence of intense heparin anticoagulation. They underscore the important inhibitory effect of GPIIb-IIIa antagonists on thrombin generation.
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Miyamoto S, Marcinkiewicz C, Edmunds LH, Niewiarowski S. Measurement of Platelet Microparticles during Cardiopulmonary Bypass by Means of Captured ELISA for GPIIb/IIIa. Thromb Haemost 2017. [DOI: 10.1055/s-0037-1615177] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
SummaryA captured enzyme-linked immunosorbent assay (ELISA) using the disintegrin, kistrin, is described and used to measure platelet microparticles (PMP) generated during open heart surgery. This ELISA detects 75 ng/ml of glycoprotein IIb/IIIa (GPIIa/IIIa) in solution and is more sensitive and less variable than flow cytometry and radioimmunoassay. By ELISA, mean values of GPIIb/IIIa in PMP are 14.2 ± 7.9 μg/ml for outdated platelets and 0.28 ± 0.1 μg/ml in fresh blood from healthy donors. Normal washed platelets (108) contain 8.8 μg of GPIIb/IIIa.In 12 cardiac surgical patients, PMP measured by ELISA significantly increased (p = 0.039) to 0.58 ± 0.3 μg/ml at the end of cardio-pulmonary bypass, but the increase measured by flow cytometry (1207 to 1447 events in PMP gate) was not significant. Neither heparin nor protamine alter PMP. After cardiopulmonary bypass, PMP concentrations return to baseline values before protamine is given. Concentrations of PMP in pericardial blood are greater than in simultaneous perfusate. This ELISA is more sensitive and accurate than alternate methods for measuring PMP and shows the PMP production and rapid clearance during open cardiac surgery.Present address: Dr. Shinji Miyamoto, Department of Cardiovascular Surgery, Oita Medical University, 1-1 Idaigaoka, Oita, Japan
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Khan MMH, Hattori T, Niewiarowski S, Edmunds LH, Colman RW. Truncated and microparticle-free soluble tissue factor bound to peripheral monocytes preferentially activate factor VII. Thromb Haemost 2017; 95:462-8. [PMID: 16525574 DOI: 10.1160/th05-06-0432] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
SummarySoluble plasma tissue factor (TF) circulates in picomolar concentrations in healthy individuals and increases in a wide spectrum of diseases. This study tests the hypothesis that both truncatedTF (rsTF) or soluble plasmaTF (pTF) in low concentration combine with monocytes or platelets to convert factorVII (fVII) to fVIIa. Both rsTF (33 kDa) and pTF (47 kDa), obtained from pericardial wounds of patients having cardiac surgery using cardiopulmonary bypass (CPB), were studied in association with blood cells and TF-bearing microparticles. Tissue factor was measured by ELISA. RsTF binds to erythrocytes, platelets, mononuclear cells and polymorphoneutrophils. The rate of fVII conversion with rsTF (1–103 nM) is highest with mononuclear cells, less with platelets, minimal with polymorphoneutrophils and undetectable with erythrocytes. Either stimulated or unstimulated mononuclear cells or platelets in the presence of 3.5 pM rsTF or pTF convert fVII (10 nM) to fVIIa, but the amounts of fVIIa produced differ. When leukocytes or platelets are absent, microparticles associated with 3.5 pM TF antigen derived from pericardial wound plasma do not activate fVII. Stimulated mononuclear cells convert nearly all available fVII (10 nM) to fVIIa with 3.5 nM pTF; unstimulated mononuclear cells convert small amounts of fVII with 1 pM rsTF. In all comparisons mononuclear cells more efficiently convert fVII to fVIIa than do platelets. This study shows that stimulated mononuclear cells provide the most efficient platform for activation of rsTF or pTF at low concentrations of TF antigen.
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Affiliation(s)
- Mohammad M H Khan
- Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-3325, USA
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Edmunds LH, Clark RE, Cohn LH, Grunkemeier GL, Miller DC, Weisel RD. Guidelines for Reporting Morbidity and Mortality after Cardiac Valvular Operations. Asian Cardiovasc Thorac Ann 2016. [DOI: 10.1177/021849239600400220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Bland KI, Rikkers LF, Lillemoe KD, Balch CM, Edmunds LH, Murie J, Warnock GL, Waddell JP, Weigelt JA, Büchler MW, Neoptolemos JP, Madoff RD, Gamelli R, Cameron J, Kelly K, Talamini M, Coran AG, Puri P, Bent AE, Rohrich RJ, McFadden D, Souba WW, Pruitt BA, Wechsler AS, Warshaw AL, Sarr M, MacFadyen BV, Cuschieri A, Park A, Swanstrom L, Arregui ME, Scott-Conner C, Sugerman HJ, Hunter JG, Lippert H, Hopt U. Consensus Statement on Mandatory Registration of Clinical Trials. Surg Innov 2016. [DOI: 10.1177/1553350607299716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Mark Talamini
- Journal of Laparoendoscopic & Advanced Surgical Techniques
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Kouchoukos NT, Edmunds LH. The 50th anniversary of the Society of Thoracic Surgeons. Ann Thorac Surg 2014; 97:S1. [PMID: 24384241 DOI: 10.1016/j.athoracsur.2013.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/01/2013] [Accepted: 10/02/2013] [Indexed: 11/18/2022]
Affiliation(s)
| | - L Henry Edmunds
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
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Affiliation(s)
- L Henry Edmunds
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania.
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Edmunds LH. The last volume of the first half century. Ann Thorac Surg 2014; 97:10. [PMID: 24384163 DOI: 10.1016/j.athoracsur.2013.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 11/11/2013] [Accepted: 11/11/2013] [Indexed: 10/25/2022]
Affiliation(s)
- L Henry Edmunds
- Editor, The Annals of Thoracic Surgery, Philadelphia, Pennsylvania.
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Edmunds LH. The fork in the road. Ann Thorac Surg 2011; 92:1-2. [PMID: 21718824 DOI: 10.1016/j.athoracsur.2011.05.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 05/11/2011] [Accepted: 05/11/2011] [Indexed: 11/29/2022]
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Parolari A, Edmunds LH. Invited commentary. Ann Thorac Surg 2010; 90:768. [PMID: 20732492 DOI: 10.1016/j.athoracsur.2010.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 05/10/2010] [Accepted: 05/10/2010] [Indexed: 10/19/2022]
Affiliation(s)
- Alessandro Parolari
- Department of Cardiac Surgery, Centro Cardiologico Monzino IRCCS, Via Parea, 4, Milano 20138, Italy.
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Abstract
Cardiopulmonary bypass increases perioperative bleeding and produces a consumptive coagulopathy, which is defined as the simultaneous production of thrombin and fibrinolysis. Thrombin formation and fibrinolysis primarily occur in the surgical wound and peak at the time heparin is reversed by protamine. Neither aprotinin nor lysine analogs successfully control bleeding in many complex procedures, reoperations, aortic resections, or in implantations of mechanical circulatory devices. This analysis reviews the mechanisms involved and current treatment protocols, with the conclusion that changes in treatment protocols rather than use of a specific anti-fibrinolytic drug may provide better control of bleeding in these patients.
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Affiliation(s)
- L Henry Edmunds
- Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-3325, USA.
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Abstract
Cardiopulmonary bypass (CPB) ignites a massive defense reaction that stimulates all blood cells and five plasma protein systems to produce a myriad of vasoactive and cytotoxic substances, cell-signaling molecules, and upregulated cellular receptors. Thrombin is the key enzyme in the thrombotic portion of the defense reaction and is only partially suppressed by heparin. During CPB, thrombin is produced by both extrinsic and intrinsic coagulation pathways and activated platelets. The routine use of a cell saver and the eventual introduction of direct thrombin inhibitors now offer the possibility of completely suppressing thrombin production and fibrinolysis during cardiac surgery with CPB.
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Affiliation(s)
- L Henry Edmunds
- Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Hattori T, Khan MMH, Colman RW, Edmunds LH. Plasma Tissue Factor Plus Activated Peripheral Mononuclear Cells Activate Factors VII and X in Cardiac Surgical Wounds. J Am Coll Cardiol 2005; 46:707-13. [PMID: 16098440 DOI: 10.1016/j.jacc.2005.05.040] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Revised: 04/28/2005] [Accepted: 05/03/2005] [Indexed: 11/21/2022]
Abstract
OBJECTIVES The purpose of this study was to test the hypothesis that activated monocytes with soluble plasma tissue factor (pTF) activate factors VII and X to generate thrombin. BACKGROUND Despite heparin, thrombin is progressively generated during cardiac surgery with cardiopulmonary bypass (CPB), produces intravascular fibrin and fibrinolysis, and causes serious thromboembolic and nonsurgical bleeding complications. Thrombin is primarily produced in the surgical wound, but mechanisms are unclear. METHODS In 13 patients, interactions of mononuclear cells, platelets, pTF, and pTF fractions to activate factors VII and X were evaluated in pre-bypass, perfusate, and pericardial wound blood before and during CPB. RESULTS Monocytes are activated in wound, but not in pre-bypass or perfusate plasma (monocyte chemotactic protein-1 = 29.5 +/- 2.1 pmoles/l vs. 2.8 +/- 1.2 pmoles/l and 3.3 +/-1.4 pmoles/l, respectively). Wound pTF is substantially elevated compared to other locations (3.64 +/- 0.45 pmoles/l vs. 0.71 +/- 0.65 pmoles/l and 1.31 +/- 1.4 pmoles/l). Supernatant wound pTF contains 81.7% of TF antigen; wound microparticle pTF contains 18.3%. Wound monocytes and all C5a-stimulated monocytes (but not activated platelets) completely convert factor VII to factor VIIa with wound pTF. Activated monocytes more efficiently activate factor X with wound supernatant TF/factor VII(VIIa) complex than with wound microparticle TF/factor VII(fVIIa). The correlation coefficient (r) between wound thrombin generation (F1.2) and wound pTF concentration is 0.944 (p = 0.0004). CONCLUSIONS During cardiac surgery with CPB, wound monocytes plus wound pTF or wound microparticle-free supernatant pTF preferentially accelerate activation of factor VII and factor X. This system represents a novel mechanism for thrombin generation via the TF coagulation pathway.
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Affiliation(s)
- Takashi Hattori
- Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Affiliation(s)
- L Henry Edmunds
- Division of Cardiothoracic Surgery, Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, USA
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Abstract
In some patients acute myocardial infarction and/or infarct expansion induces progressive left ventricular dilatation that eventually leads to heart failure and death. The five year mortality after onset of heart failure is 50%. Chronically stretched viable myocardium adjacent to or remote from an expanding infarction initiates a myopathic process that leads to progressive myocyte apoptosis and adverse postinfarction remodeling. Revascularization of stunned or hibernating myocardium restores contractility and benefits patients in heart failure; however, revascularization does not restore contractility to myopathic, remodeling myocardium. Contemporary operations for heart failure temporarily reduce ventricular wall stress, but fail to reverse stretch induced myocyte apoptosis, which may not be reversible. Logically, prevention of this myopathic process after acute infarction seems required to extend survival. It follows that surgeons should operate before adverse postinfarction left ventricular remodeling occurs, using new operations, rather than afterwards.
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Affiliation(s)
- L Henry Edmunds
- University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
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Guy TS, Moainie SL, Gorman JH, Jackson BM, Plappert T, Enomoto Y, St John-Sutton MG, Edmunds LH, Gorman RC. Prevention of ischemic mitral regurgitation does not influence the outcome of remodeling after posterolateral myocardial infarction. J Am Coll Cardiol 2004; 43:377-83. [PMID: 15013117 DOI: 10.1016/j.jacc.2003.07.045] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2003] [Revised: 07/17/2003] [Accepted: 07/21/2003] [Indexed: 10/26/2022]
Abstract
OBJECTIVES This study was designed to test the hypothesis that ischemic mitral regurgitation (IMR) results from, but does not influence, the progression of left ventricular (LV) remodeling after posterolateral infarction. BACKGROUND Surgical correction of chronic IMR is being increasingly recommended. METHODS Three groups of sheep had coronary snares placed around the second and third obtuse marginal coronary arteries. Occlusion of these vessels in the control group resulted in progressive IMR over eight weeks. In a second group, Merseline mesh was fitted to cover the exposed LV before infarction. In a third group, a ring annuloplasty was placed before infarction to prevent IMR. Remodeling and degree of IMR were assessed with echocardiography at baseline and at 30 min and two, five, and eight weeks after infarction. RESULTS Eight weeks after infarction, mean IMR grade was significantly higher in control animals than mesh and annuloplasty animals. At eight weeks, LV end-systolic volume and end-systolic muscle-to-cavity-area ratio (ESMCAR) were significantly better in mesh-treated sheep than in control sheep; also, at eight weeks, ESMCAR and akinetic segment length were significantly better in mesh-treated sheep than in annuloplasty sheep. Ejection fraction was significantly higher in the mesh than the annuloplasty group. There was no significant difference in any measure of remodeling between the annuloplasty and control groups. CONCLUSIONS Prophylactic ventricular restraint reduces infarct expansion, attenuates adverse remodeling, and reduces IMR severity. Prevention of IMR by prophylactic ring annuloplasty does not influence remodeling. Ischemic mitral regurgitation is a consequence, not a cause, of postinfarction remodeling; infarct expansion is the more important therapeutic target.
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Affiliation(s)
- T Sloane Guy
- Harrison Department of Surgical Research, University of Pennsylvania School of Medicine, 3400 Spruce Street, Philadelphia, PA 19104, USA
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Affiliation(s)
- L Henry Edmunds
- Harrison Department of Surgical Research, School of Medicine, University of, Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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Gorman JH, Gorman RC, Jackson BM, Enomoto Y, St John-Sutton MG, Edmunds LH. Annuloplasty ring selection for chronic ischemic mitral regurgitation: lessons from the ovine model. Ann Thorac Surg 2003; 76:1556-63. [PMID: 14602285 DOI: 10.1016/s0003-4975(03)00891-9] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Chronic ischemic mitral regurgitation (CIMR) is poorly understood and repair operations are often unsatisfactory. This study elucidates the mechanism of CIMR in an ovine model. METHODS Sonomicrometry array localization measured the three-dimensional geometry of the mitral annulus and subvalvular apparatus in five sheep before and 8 weeks after a posterior infarction of the left ventricle that produced progressive severe CIMR. RESULTS End systolic annular area increased from 647 +/- 44 mm(2) to 1,094 +/- 173 mm(2) (p = 0.01). Annular dilatation occurred equally along the anterior (47.0 +/- 5.6 mm to 60.2 +/- 4.9 mm, p = 0.001) and posterior (53.8 +/- 3.1 mm to 68.5 +/- 8.4 mm, p = 0.005) portions of the annulus. The tip of the anterior papillary muscle moved away from both the anterior and posterior commissures by 5.2 +/- 3.2 mm (p = 0.021) and 7.3 +/- 2.2 mm (p = 0.002), respectively. The distance from the tip of the posterior papillary muscle to the anterior commissure increased by 11.0 +/- 5.7 mm (p = 0.032) while the distance from the tip of the posterior papillary muscle to the posterior commissure remained constant. CONCLUSIONS Progressive dilatation of both the anterior and posterior mitral annuli, increased annular area, and asymmetric ventricular dilatation combine to cause CIMR by distortion of mitral valve geometry and tethering of leaflet coaptation. Therefore complete ring annuloplasty may be superior to partial annuloplasty in the treatment of CIMR.
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Affiliation(s)
- Joseph H Gorman
- Harrison Department of Surgical Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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Wilson EM, Moainie SL, Baskin JM, Lowry AS, Deschamps AM, Mukherjee R, Guy TS, St John-Sutton MG, Gorman JH, Edmunds LH, Gorman RC, Spinale FG. Region- and type-specific induction of matrix metalloproteinases in post-myocardial infarction remodeling. Circulation 2003; 107:2857-63. [PMID: 12771000 DOI: 10.1161/01.cir.0000068375.40887.fa] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Induction of matrix metalloproteinases (MMPs) contributes to adverse remodeling after myocardial infarction (MI). Whether a region- and type-specific distribution of MMPs occurs within the post-MI myocardium remained unknown. METHODS AND RESULTS Ten sheep were instrumented with a sonomicrometry array to measure dimensions in 7 distinct regions corresponding to the remote, transition, and MI regions. Eight sheep served as reference controls. The relative abundance of representative MMP types and the tissue inhibitors of the MMPs (TIMPs) was quantified by immunoblotting. Segment length increased from baseline in the remote (24.9+/-5.4%), transition (18.0+/-2.9%), and MI (53.8+/-11.0%) regions at 8 weeks after MI (P<0.05) and was greatest in the MI region (P<0.05). Region- and type-specific changes in MMPs occurred after MI. For example, MMP-1 and MMP-9 abundance was unchanged in the remote, fell to 3+/-2% in the transition, and was undetectable in the MI region (P<0.05). MMP-13, MMP-8, and MT1-MMP increased by >300% in the transition and MI regions (P<0.05). TIMP abundance decreased significantly in the transition region after MI and fell to undetectable levels within the MI region. CONCLUSIONS The unique findings of this study were 2-fold. First, changes in regional geometry after MI were associated with changes in MMP levels. Second, a region-specific portfolio of MMPs was induced after MI and was accompanied by a decline in TIMP levels, indicative of a loss of MMP inhibitory control. Targeting the regional imbalance between specific MMPs and TIMPs within the post-MI myocardium holds therapeutic potential.
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Affiliation(s)
- Eric M Wilson
- Medical University of South Carolina, Charleston, SC 29425, USA
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Jackson BM, Gorman JH, Salgo IS, Moainie SL, Plappert T, St John-Sutton M, Edmunds LH, Gorman RC. Border zone geometry increases wall stress after myocardial infarction: contrast echocardiographic assessment. Am J Physiol Heart Circ Physiol 2003; 284:H475-9. [PMID: 12414441 DOI: 10.1152/ajpheart.00360.2002] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
After myocardial infarction (MI), the border zone expands chronically, causing ventricular dilatation and congestive heart failure (CHF). In an ovine model (n = 4) of anteroapical MI that results in CHF, contrast echocardiography was used to image short-axis left ventricular (LV) cross sections and identify border zone myocardium before and after coronary artery ligation. In the border zone at end systole, the LV endocardial curvature (K) decreased from 0.86 +/- 0.33 cm(-1) at baseline to 0.35 +/- 0.19 cm(-1) at 1 h (P < 0.05), corresponding to a mean decrease of 55%. Also in the border zone, the wall thickness (h) decreased from 1.14 +/- 0.26 cm at baseline to 1.01 +/- 0.25 cm at 1 h (P < 0.05), corresponding to a mean decrease of 11%. By Laplace's law, wall stress is inversely proportional to the product K. h. Therefore, a 55% decrease in K results in a 122% increase in circumferential stress; a 11% decrease in h results in a 12% increase in circumferential stress. These findings indicate that after MI, geometric changes cause increased dynamic wall stress, which likely contributes to border zone expansion and remodeling.
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Affiliation(s)
- Benjamin M Jackson
- Department of Surgery and the Harrison Department of Surgical Research, Hospital of the University of Pennsylvania, Philadelphia 19104, USA
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Edmunds LH, Pusztay HM, Benson JM, Bluemle AA, Davidson CA, Sutherland RJ, Wilson SM. New inside and out. Ann Thorac Surg 2003; 75:11-4. [PMID: 12537184 DOI: 10.1016/s0003-4975(02)04830-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Jackson BM, Gorman JH, Moainie SL, Guy TS, Narula N, Narula J, John-Sutton MG, Edmunds LH, Gorman RC. Extension of borderzone myocardium in postinfarction dilated cardiomyopathy. J Am Coll Cardiol 2002; 40:1160-7; discussion 1168-71. [PMID: 12354444 DOI: 10.1016/s0735-1097(02)02121-6] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study tests the hypothesis that hypocontractile, borderzone myocardium adjacent to an expanding infarct becomes progressively larger and more hypocontractile as remodeling continues. Early infarct expansion following anteroapical myocardial infarction (MI) is associated with progressive ventricular dilation and heart failure. The contribution of perfused, hypocontractile, borderzone myocardium to this process is unknown. Using a sheep model of anteroapical infarction, sonomicrometry array localization and serial microsphere injections were used to track changes in regional myocardial contractility, geometry, and perfusion. Eight sheep were studied before and after infarction and two, five, and eight weeks later. Thirty intertransducer chord lengths were analyzed to measure regional contractility and serial changes in regional geometry at end systole. Beginning as a narrow band of fully perfused hypocontractile myocardium adjacent to the infarction, borderzone myocardium extends to involve additional contiguous myocardium that progressively loses contractile function as the heart remodels. Three distinct myocardial zones develop as a result of transmural MI: infarct, borderzone (perfused but hypocontractile), and remote (perfused and normally functioning).This study demonstrates that hypocontractile, fully perfused borderzone myocardium extends to involve contiguous normal myocardium during postinfarction remodeling. This borderzone myocardium is a unique type of perfused, hypocontractile myocardium, which is distinct from hibernating or stunned myocardium. Preventing extension of borderzone myocardium by medical or surgical means offers the prospect of preventing late-onset heart failure following transmural expanding MIs.
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Affiliation(s)
- Benjamin M Jackson
- Harrison Department of Surgical Research, Philadelphia, Pennsylvania 19104, USA
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Moainie SL, Gorman JH, Guy TS, Bowen FW, Jackson BM, Plappert T, Narula N, St John-Sutton MG, Narula J, Edmunds LH, Gorman RC. An ovine model of postinfarction dilated cardiomyopathy. Ann Thorac Surg 2002; 74:753-60. [PMID: 12238835 DOI: 10.1016/s0003-4975(02)03827-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Coronary arterial disease is the major cause of congestive heart failure, but suitable animal models of postinfarction, dilated cardiomyopathy do not exist. This article describes an ovine model that develops after an anterobasal infarction. METHODS The distribution of ovine myocardium supplied by the first two diagonal branches of the left homonymous artery were determined in 20 slaughterhouse hearts and eight live sheep using methylene blue and tetrazolium injections, respectively. Seven additional animals had the infarction and underwent serial hemodynamic, microsphere and echocardiographic studies more than 8 weeks and histologic studies at the eighth week. Infarcts represented 24.6% +/- 4.7% and 23.9% +/- 2.2% of the left ventricular mass in slaughterhouse and live hearts, respectively. RESULTS During remodeling, left ventricular end-systolic and end-diastolic volumes increased 115% and 73%, respectively, ejection fraction decreased from 41.2% +/- 6.7% to 29.1% +/- 5.7%, systolic wall thickening remote from the infarct decreased by 68%, sphericity index increased from 0.465 +/- 0.088 to 0.524 +/- 0.038, and left ventricular end-diastolic pressure increased from 1.7 +/- 1.0 to 8.2 +/- 3.5 mm Hg. Serial microsphere measurements documented normal blood flow (1.34 mL/g per minute) to all uninfarcted myocardium and 22% of normal to the infarct. Viable myocardium showed mild interstitial fibrosis. CONCLUSIONS This ovine model meets all criteria for postinfarction, dilated cardiomyopathy and has the advantages of controlling for variations in coronary arterial anatomy, collateral vascularity, and differences in the numbers, location, and severity of atherosclerotic lesions that confound human studies of the pathogenesis of this disease. This simple model contains only infarcted and fully perfused, hypocontractile myocardium produced by a moderate-sized, regional infarction.
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Affiliation(s)
- Sina L Moainie
- Harrison Department of Surgical Research, University of Pennsylvania School of Medicine, Philadelphia, USA
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Abstract
BACKGROUND Leaflet curvature is known to reduce mechanical stress. There are 2 major components that contribute to this curvature. Leaflet billowing introduces the most obvious form of leaflet curvature. The saddle shape of the mitral annulus imparts a more subtle form of leaflet curvature. This study explores the relative contributions of leaflet billowing and annular shape on leaflet curvature and stress distribution. METHODS AND RESULTS Both numerical simulation and experimental data were used. The simulation consisted of an array of numerically generated mitral annular phantoms encompassing flat to markedly saddle-shaped annular heights. Highest peak leaflet stresses occurred for the flat annulus. As saddle height increased, peak stresses decreased. The minimum peak leaflet stress occurred at an annular height to commissural width ratio of 15% to 25%. The second phase involved data acquisition for the annulus from 3 humans by 3D echocardiography, 3 sheep by sonomicrometry array localization, 2 sheep by 3D echocardiography, and 2 baboons by 3D echocardiography. All 3 species imaged had annuli of a similar shape, with an annular height to commissural width ratio of 10% to 15%. CONCLUSION The saddle shape of the mitral annulus confers a mechanical advantage to the leaflets by adding curvature. This may be valuable when leaflet curvature becomes reduced due to diminished leaflet billowing caused by annular dilatation. The fact that the saddle shape is conserved across mammalian species provides indirect evidence of the advantages it confers. This analysis of mitral annular contour may prove applicable in developing the next generation of mitral annular prostheses.
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Moainie SL, Guy TS, Gorman JH, Plappert T, Jackson BM, St John-Sutton MG, Edmunds LH, Gorman RC. Infarct restraint attenuates remodeling and reduces chronic ischemic mitral regurgitation after postero-lateral infarction. Ann Thorac Surg 2002; 74:444-9; discussion 449. [PMID: 12173827 DOI: 10.1016/s0003-4975(02)03747-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Chronic ischemic mitral regurgitation (IMR) is produced by adverse postinfarction ventricular remodeling. We hypothesize that restraining infarct expansion reduces left-ventricular (LV) dilatation and the severity of mitral regurgitation. METHODS Two groups of 6 sheep had coronary snares placed around the second and third obtuse marginal coronary arteries and four piezoelectric transducers sutured within myocardium across the mid short axis of the LV. In one group, a patch of Marlex mesh was precisely fitted and lightly sutured to myocardium destined for infarction (determined by temporary snare occlusion). Two weeks after instrumentation, coronary snares were tied tight to infarct approximately 24% of the posterolateral LV mass. Transdiaphragmatic echocardiograms were obtained in all animals at baseline, and 30 minutes, and 2, 5, and 8 weeks after infarction. RESULTS Echocardiograms confirmed similar infarct sizes and locations in both groups. Eight weeks after infarction, IMR grade averaged 3.6+ (scale: 0, no MR; 4, severe MR) in control sheep and 1.9+ in mesh-restrained animals (p = 0.0001). LV end-diastolic and end-systolic volumes at the eighth week were less in mesh-treated sheep (87 +/- 11.3 vs 113 +/- 18.3; 61 +/- 10.6 vs 77 +/- 14.1, respectively), but differences were not significant. Data from mid short axis piezoelectric transducers indicated significantly less strain in the infarcted myocardium in mesh-restrained sheep than in control. CONCLUSIONS Early restraint of postero-lateral infarct expansion attenuates the severity of ischemic mitral regurgitation and slows ventricular dilatation. However, the remodeling process is not arrested 8 weeks after infarction.
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Affiliation(s)
- Sina L Moainie
- Harrison Department of Surgical Research, University of Pennsylvania School of Medicine, Philadelphia, USA
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Abstract
John Gibbon conceived cardiopulmonary bypass (CPB) and performed the first intracardiac repair using extracorporeal perfusion in 1953. This achievement stimulated rapid development of the knowledge base and equipment necessary for accurate diagnoses and successful intracardiac operations. In the early 60s increasing evidence indicated that exposure of blood to nonendothelial cell surfaces produced bleeding and thrombotic complications and a massive inflammatory response. Early efforts to discover a synthetic, nonthrombogenic surface gave way to efforts to control the 'whole-body inflammatory response' by pharmacological means. These efforts are ongoing; progress is slow; and heparin is still required for most applications of extracorporeal perfusion technology. Nevertheless, CPB now enables over one million cardiac surgical operations each year. Future progress and the development of artificial internal organs that process blood depend upon control of the blood-surface interface without anticoagulants.
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Affiliation(s)
- L Henry Edmunds
- Harrison Department of Surgical Research, School of Medicine, University of Pennsylvania, Philadelphia 19104-4283, USA.
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Bowen FW, Jones SC, Narula N, St John Sutton MG, Plappert T, Edmunds LH, Dixon IM. Restraining acute infarct expansion decreases collagenase activity in borderzone myocardium. Ann Thorac Surg 2001; 72:1950-6. [PMID: 11791588 DOI: 10.1016/s0003-4975(01)03282-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND After acute myocardial infarction, regional myocardial wall strains and stresses change and a complex cellular and biochemical response is initiated to remodel the ventricle. This study tests the hypothesis that changes in regional ventricular wall strains affect regional collagen accumulation and collagenase activity. METHODS Fourteen sheep had acute anteroapical infarction that progressively expands into left ventricular aneurysm within 8 weeks. In 7 sheep, infarct expansion was restrained by prior placement of mesh over the area at risk. Fourteen days after infarction, and after hemodynamic and echocardiographic measurements, animals were euthanized for histology, measurements of hydroxyproline, matrix metalloproteinase-1 (MMP-1 or collagenase) and MMP-2 (gelatinase) activity, as well as collagen type I and III in infarcted, borderzone, and remote myocardium. RESULTS Restraining infarct expansion does not change collagen content or MMP-1 or MMP-2 activity in the infarct, but significantly increases the ratio of collagen I/III. In borderzone and remote myocardium infarct, restraint significantly increases collagen content and significantly reduces MMP-1 activity. MMP-2 activity is reduced (p = 0.059) in borderzone myocardium only. Between groups, the ratio of type I/III fibrillar collagen does not change in borderzone myocardium. CONCLUSIONS Fourteen days after acute myocardial infarction, restraining infarct expansion increases collagen accumulation in borderzone and remote myocardium, which may prevent expansion of hypocontractile, fully perfused "remodeling myocardium" adjacent to the infarct. This study demonstrates that changes in regional myocardial wall strain alter the cellular and biochemical processes involved in postinfarction ventricular remodeling.
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Affiliation(s)
- F W Bowen
- Department of Surgery, School of Medicine, University of Pennsylvania, Philadelphia, USA
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Bowen FW, Hattori T, Narula N, Salgo IS, Plappert T, Sutton MG, Edmunds LH. Reappearance of myocytes in ovine infarcts produced by six hours of complete ischemia followed by reperfusion. Ann Thorac Surg 2001; 71:1845-55. [PMID: 11426758 DOI: 10.1016/s0003-4975(01)02642-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND In this study we tested the hypothesis that delayed reperfusion of ischemic myocardium-too late to save myocytes-attenuates infarct expansion and improves collagen synthesis. METHODS The hypothesis was tested in a sheep model of anteroapical infarction that has no collateral blood flow to the area at risk. After coronary ligation or arterial occlusion for 1 or 6 hours, sheep had serial hemodynamic and quantitative echocardiographic studies before and after infarction and 2, 5, 8, and 12 weeks later. Hearts were examined by light and electron microscopy at 2 and 12 weeks; hydroxyproline and ratios of type I/III collagen were measured at 12 weeks. RESULTS After coronary occlusion, left ventricular (LV) function progressively decreased and size increased to form an anteroapical aneurysm. After 1 hour of ischemia, neither resting LV size nor function changed; the infarct contained a midmyocardial scar between epicardial and endocardial muscle. After 6 hours of ischemia, LV function was significantly better than that in nonperfused sheep. Two weeks after 6 hours of ischemia, no viable myocytes were visible by light microscopy, but electron micrographs showed rare intact nucleated myocytes with scarce cytoplasmic myofibrils. At the 12th week epicardial and endocardial myocytes reappeared in the infarct. Infarct collagen type I/III ratios were 1.2 in reperfused groups and 0.7 in nonperfused sheep. CONCLUSIONS Delayed reperfusion causes loss and subsequent reappearance of ovine epicardial myocytes, improves collagen type I/III ratios, and attenuates LV dilatation and loss of function. One hypothesis to explain the reappearance of myocytes is that reperfusion partially reverses an incomplete apoptotic process.
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Affiliation(s)
- F W Bowen
- Department of Surgery, School of Medicine, University of Pennsylvania, Philadelphia, USA
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Affiliation(s)
- L H Edmunds
- Hospital of the University of Pennsylvania, Philadelphia, PA 19104-4283, USA.
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Soulika AM, Khan MM, Hattori T, Bowen FW, Richardson BA, Hack CE, Sahu A, Edmunds LH, Lambris JD. Inhibition of heparin/protamine complex-induced complement activation by Compstatin in baboons. Clin Immunol 2000; 96:212-21. [PMID: 10964539 DOI: 10.1006/clim.2000.4903] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Complement activation products are major components of the inflammatory response induced by cardiac surgery and cardiopulmonary bypass which contribute to postoperative organ dysfunction, fluid accumulation, and morbidity. Activation of the complement system occurs during extracorporeal circulation, during reperfusion of ischemic tissue, and after the formation of heparin-protamine complexes. In this study we examine the efficacy of Compstatin, a recently discovered peptide inhibitor of complement, in preventing heparin/protamine-induced complement activation in baboons. The study was performed in baboons because Compstatin binds to baboon C3 and is resistant to proteolytic cleavage in baboon blood (similar to humans); Compstatin inhibits only the activation of primates' complement system. After testing various doses and administration regimens, Compstatin produced complete inhibition at a total dose of 21 mg/kg when given as a combination of bolus injection and infusion. Compstatin completely inhibited in vivo heparin/protamine-induced complement activation without adverse effects on heart rate or systemic arterial, central venous, and pulmonary arterial pressures. This study indicates that Compstatin is a safe and effective complement inhibitor that has the potential to prevent complement activation during and after clinical cardiac surgery. Furthermore, Compstatin can serve as the prototype for designing an orally administrated drug.
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Affiliation(s)
- A M Soulika
- Department of Pathology and Laboratory Medicine School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA
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Edmunds LH, Mckinlay S, Anderson JM, Callahan TH, Chesebro JH, Geiser EA, Makanani DM, McIntire LV, Meeker WQ, Naughton GK, Panza JA, Schoen FJ, Didisheim P. Directions for improvement of substitute heart valves: National Heart, Lung, and Blood Institute's Working Group report on heart valves. J Biomed Mater Res 2000; 38:263-6. [PMID: 9283972 DOI: 10.1002/(sici)1097-4636(199723)38:3<263::aid-jbm11>3.0.co;2-c] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- L H Edmunds
- Department of Surgery, University of Pennsylvania, Philadelphia, USA
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Khan MM, Gikakis N, Miyamoto S, Rao AK, Cooper SL, Edmunds LH, Colman RW. Aprotinin inhibits thrombin formation and monocyte tissue factor in simulated cardiopulmonary bypass. Ann Thorac Surg 1999; 68:473-8. [PMID: 10475415 DOI: 10.1016/s0003-4975(99)00551-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Aprotinin reduces perioperative bleeding after open heart surgery, primarily by inhibiting fibrinolysis. In addition, the drug has both procoagulant and anticoagulant effects that involve complex reactions of coagulation proteins and cells that are incompletely understood. This study tests the hypothesis that aprotinin has an anticoagulant effect on the extrinsic coagulation pathway. METHODS Human heparinized blood was recirculated through a membrane oxygenator with and without high concentrations of aprotinin (18.4 microM). Serial plasma samples were obtained at intervals up to 240 minutes. RESULTS Aprotinin significantly reduced the progressive increase in prothrombin fragments (F1.2) and thrombin-antithrombin complex beginning immediately. Aprotinin also significantly reduced monocyte expression of tissue factor and Mac-1. Aprotinin did not significantly reduce factor VII or factor VIIa. CONCLUSIONS During simulated cardiopulmonary bypass, aprotinin immediately inhibits kallikrein and thrombin formation via the intrinsic coagulation pathway. Later, aprotinin inhibits monocyte expression of tissue factor and the extrinsic coagulation pathway. The ability of aprotinin to inhibit monocyte tissue factor provides a means to reduce thrombin formation in blood aspirated from the wound during open heart surgery.
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Affiliation(s)
- M M Khan
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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Rao AK, Sun L, Hiramatsu Y, Gorman JH, Edmunds LH. Glycoprotein IIb/IIIa receptor antagonist tirofiban inhibits thrombin generation during cardiopulmonary bypass in baboons. Thromb Haemost 1999; 82:140-4. [PMID: 10456468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Platelets play a major role in coagulation mechanisms and anti-GPIIb-IIIa antibodies inhibit tissue-factor induced thrombin generation in in vitro studies. Tirofiban, a nonpeptide selective glycoprotein (GP) IIb/IIIa antagonist, preserves platelet number and function during cardiopulmonary bypass (CPB) in baboons. We tested the hypothesis that platelet inhibition by tirofiban inhibits thrombin generation in vivo. Four groups of baboons (n = 7-12) were perfused for 60 min; all groups received heparin (300 units/kg). The controls received only heparin. The low dose (0.1 microg/kg/min) and high dose (0.3 microg/kg/min) infusion groups received tirofiban for 60 min before and 60 min during CPB. The bolus plus low dose infusion group received a 15 microg/kg bolus before starting CPB and a low dose infusion (0.1 mg/kg/min) only during CPB. At end of CPB, compared to control group (2.99+/-0.36 nM), prothrombin fragment F1.2 levels were lower (p<0.05) in low dose infusion group (1.65+/-0.14 nM, mean +/- SE) and high dose infusion group (1.71+/-0.19 nM), but not bolus plus infusion group (2.69+/-0.49 nM); they remained significantly lower after protamine administration. At end of CPB, thrombin-antithrombin complex levels were lower in high dose infusion group (40.0+/-11.2 ng/ml, p<0.05) compared to control group (76.2+/-7.3 ng/ml). These studies indicate that tirofiban inhibits not only platelet aggregation but also thrombin generation in vivo during CPB, and that this effect is demonstrable even in the presence of intense heparin anticoagulation. They underscore the important inhibitory effect of GPIIb-IIIa antagonists on thrombin generation.
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Affiliation(s)
- A K Rao
- Sol Sherry Thrombosis Research Center, Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
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Suzuki Y, Malekan R, Hanson CW, Niewiarowski S, Sun L, Rao AK, Edmunds LH. Platelet anesthesia with nitric oxide with or without eptifibatide during cardiopulmonary bypass in baboons. J Thorac Cardiovasc Surg 1999; 117:987-93. [PMID: 10220694 DOI: 10.1016/s0022-5223(99)70380-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVE This study tested the hypothesis that nitric oxide or nitric oxide and eptifibatide (Integrilin) reversibly inhibit platelet activation and consumption during cardiopulmonary bypass and rapidly restore platelet numbers and function after bypass. METHODS Nitric oxide, a short-acting, reversible platelet inhibitor, was studied with and without eptifibatide, a short-acting, reversible glycoprotein IIb/IIIa inhibitor, in 21 baboons that underwent 60 minutes of normothermic cardiopulmonary bypass with peripheral cannulas. A control group, a group that received 80 ppm nitric oxide, and a group that received both nitric oxide and eptifibatide were studied. Blood samples were obtained at several time points to determine platelet count, aggregation in response to adenosine diphosphate, and levels of beta-thromboglobulin, prothrombin fragment 1.2, and thrombin-antithrombin complex. Template bleeding times were measured before and at 4 intervals after cardiopulmonary bypass. RESULTS Both nitric oxide and the combination of the 2 drugs significantly attenuated platelet consumption, improved postbypass function, and reduced plasma beta-thromboglobulin release with respect to values in control animals. Both nitric oxide and the combination restored baseline bleeding times 55 minutes after cardiopulmonary bypass ended. No significant differences between nitric oxide and the combination were found for any measurement. CONCLUSION Nitric oxide with or without eptifibatide protects platelets during cardiopulmonary bypass and accelerates restoration of normal bleeding times after operation in a baboon model. Although nitric oxide and eptifibatide reversibly inhibit platelets by different mechanisms, in the absence of a wound no synergistic effect was demonstrated.
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Affiliation(s)
- Y Suzuki
- Harrison Surgical Research Laboratories, Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, USA
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