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Aggarwal R, Qi SS, So SW, Swingen C, Reyes CP, Rose R, Wright C, Hocum Stone LL, Nixon JP, McFalls EO, Butterick TA, Kelly RF. Persistent diastolic dysfunction in chronically ischemic hearts following coronary artery bypass graft. J Thorac Cardiovasc Surg 2023; 165:e269-e279. [PMID: 36154976 PMCID: PMC10100582 DOI: 10.1016/j.jtcvs.2022.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 08/10/2022] [Accepted: 08/13/2022] [Indexed: 11/17/2022]
Abstract
OBJECTIVE A porcine model was used to study diastolic dysfunction in hibernating myocardium (HM) and recovery with coronary artery bypass surgery (CABG). METHODS HM was induced in Yorkshire-Landrace juvenile swine (n = 30) by placing a c-constrictor on left anterior descending artery causing chronic myocardial ischemia without infarction. At 12 weeks, animals developed the HM phenotype and were either killed humanely (HIB group; n = 11) or revascularized with CABG and allowed 4 weeks of recovery (HIB+CABG group; n = 19). Control pigs were matched for weight, age, and sex to the HIB group. Before the animals were killed humanely, cardiac magnetic resonance imaging (MRI) was done at rest and during a low-dose dobutamine infusion. Tissue was obtained for histologic and proinflammatory biomarker analyses. RESULTS Diastolic peak filling rate was lower in HIB compared with control (5.4 ± 0.7 vs 6.7 ± 1.4 respectively, P = .002), with near recovery with CABG (6.3 ± 0.8, P = .06). Cardiac MRI confirmed preserved global systolic function in all groups. Histology confirmed there was no transmural infarction but showed interstitial fibrosis in the endomysium in both the HIB and HIB+CABG groups compared with normal myocardium. Alpha-smooth muscle actin stain identified increased myofibroblasts in HM that were less apparent post-CABG. Cytokine and proteomic studies in HM showed decreased peroxisome proliferator-activator receptor gamma coactivator 1-alpha (PGC1-α) expression but increased expression of granulocyte-macrophage colony-stimulating factor and nuclear factor kappa-light-chain enhancer of activated B cells (NFκB). Following CABG, PGC1-α and NFκB expression returned to control whereas granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-α, and interferon gamma remained increased. CONCLUSIONS In porcine model of HM, increased NFκB expression, enhanced myofibroblasts, and collagen deposition along with decreased PGC1-α expression were observed, all of which tended toward normal with CABG. Estimates of impaired relaxation with MRI within HM during increased workload persisted despite CABG, suggesting a need for adjuvant therapies during revascularization.
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Affiliation(s)
- Rishav Aggarwal
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minn
| | - Steven S Qi
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minn
| | - Simon W So
- Research Service, Minneapolis Veterans Affairs Health Care System, Minneapolis, Minn; Department of Neuroscience, University of Minnesota, Minneapolis, Minn; Center for Veterans Research and Education, Division of Cardiology and Cardiothoracic Surgery, Minneapolis, Minn
| | - Cory Swingen
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minn
| | - Christina P Reyes
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minn
| | - Rebecca Rose
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minn
| | - Christin Wright
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minn
| | - Laura L Hocum Stone
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minn
| | - Joshua P Nixon
- Research Service, Minneapolis Veterans Affairs Health Care System, Minneapolis, Minn
| | - Edward O McFalls
- Division of Cardiology, Richmond VA Medical Center, Richmond, Va
| | - Tammy A Butterick
- Department of Neuroscience, University of Minnesota, Minneapolis, Minn; Center for Veterans Research and Education, Division of Cardiology and Cardiothoracic Surgery, Minneapolis, Minn
| | - Rosemary F Kelly
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, Minn.
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Aggarwal R, Potel KN, Shao A, So SW, Swingen C, Reyes CP, Rose R, Wright C, Hocum Stone LL, McFalls EO, Butterick TA, Kelly RF. An Adjuvant Stem Cell Patch with Coronary Artery Bypass Graft Surgery Improves Diastolic Recovery in Porcine Hibernating Myocardium. Int J Mol Sci 2023; 24:ijms24065475. [PMID: 36982547 PMCID: PMC10049498 DOI: 10.3390/ijms24065475] [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: 01/13/2023] [Revised: 03/02/2023] [Accepted: 03/10/2023] [Indexed: 03/15/2023] Open
Abstract
Diastolic dysfunction persists despite coronary artery bypass graft surgery (CABG) in patients with hibernating myocardium (HIB). We studied whether the adjunctive use of a mesenchymal stem cells (MSCs) patch during CABG improves diastolic function by reducing inflammation and fibrosis. HIB was induced in juvenile swine by placing a constrictor on the left anterior descending (LAD) artery, causing myocardial ischemia without infarction. At 12 weeks, CABG was performed using the left-internal-mammary-artery (LIMA)-to-LAD graft with or without placement of an epicardial vicryl patch embedded with MSCs, followed by four weeks of recovery. The animals underwent cardiac magnetic resonance imaging (MRI) prior to sacrifice, and tissue from septal and LAD regions were collected to assess for fibrosis and analyze mitochondrial and nuclear isolates. During low-dose dobutamine infusion, diastolic function was significantly reduced in HIB compared to the control, with significant improvement after CABG + MSC treatment. In HIB, we observed increased inflammation and fibrosis without transmural scarring, along with decreased peroxisome proliferator-activated receptor-gamma coactivator (PGC1α), which could be a possible mechanism underlying diastolic dysfunction. Improvement in PGC1α and diastolic function was noted with revascularization and MSCs, along with decreased inflammatory signaling and fibrosis. These findings suggest that adjuvant cell-based therapy during CABG may recover diastolic function by reducing oxidant stress–inflammatory signaling and myofibroblast presence in the myocardial tissue.
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Affiliation(s)
- Rishav Aggarwal
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (R.A.); (A.S.); (C.S.); (C.P.R.); (R.R.); (C.W.); (L.L.H.S.)
| | - Koray N. Potel
- School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast BT9 7BL, UK;
| | - Annie Shao
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (R.A.); (A.S.); (C.S.); (C.P.R.); (R.R.); (C.W.); (L.L.H.S.)
| | - Simon W. So
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; (S.W.S.); (T.A.B.)
- Department of Research, Center for Veterans Research and Education, Minneapolis, MN 55417, USA
| | - Cory Swingen
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (R.A.); (A.S.); (C.S.); (C.P.R.); (R.R.); (C.W.); (L.L.H.S.)
| | - Christina P. Reyes
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (R.A.); (A.S.); (C.S.); (C.P.R.); (R.R.); (C.W.); (L.L.H.S.)
| | - Rebecca Rose
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (R.A.); (A.S.); (C.S.); (C.P.R.); (R.R.); (C.W.); (L.L.H.S.)
| | - Christin Wright
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (R.A.); (A.S.); (C.S.); (C.P.R.); (R.R.); (C.W.); (L.L.H.S.)
| | - Laura L. Hocum Stone
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (R.A.); (A.S.); (C.S.); (C.P.R.); (R.R.); (C.W.); (L.L.H.S.)
| | - Edward O. McFalls
- Division of Cardiology, Richmond VA Medical Center, Richmond, VA 23249, USA;
| | - Tammy A. Butterick
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; (S.W.S.); (T.A.B.)
- Department of Research, Center for Veterans Research and Education, Minneapolis, MN 55417, USA
| | - Rosemary F. Kelly
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (R.A.); (A.S.); (C.S.); (C.P.R.); (R.R.); (C.W.); (L.L.H.S.)
- Correspondence: ; Tel.: +1-612-625-3902
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Aggarwal R, Potel KN, McFalls EO, Butterick TA, Kelly RF. Novel Therapeutic Approaches Enhance PGC1-alpha to Reduce Oxidant Stress-Inflammatory Signaling and Improve Functional Recovery in Hibernating Myocardium. Antioxidants (Basel) 2022; 11:2155. [PMID: 36358527 PMCID: PMC9686496 DOI: 10.3390/antiox11112155] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 10/29/2022] [Accepted: 10/30/2022] [Indexed: 09/02/2023] Open
Abstract
Ischemic heart disease affects millions of people around the world. Current treatment options, including coronary artery bypass grafting, do not result in full functional recovery, highlighting the need for novel adjunctive therapeutic approaches. Hibernation describes the myocardial response to prolonged ischemia and involves a set of complex cytoprotective metabolic and functional adaptations. PGC1-alpha, a key regulator of mitochondrial energy metabolism and inhibitor of oxidant-stress-inflammatory signaling, is known to be downregulated in hibernating myocardium. PGC1-alpha is a critical component of cellular stress responses and links cellular metabolism with inflammation in the ischemic heart. While beneficial in the acute setting, a chronic state of hibernation can be associated with self-perpetuating oxidant stress-inflammatory signaling which leads to tissue injury. It is likely that incomplete functional recovery following revascularization of chronically ischemic myocardium is due to persistence of metabolic changes as well as prooxidant and proinflammatory signaling. Enhancement of PGC1-alpha signaling has been proposed as a possible way to improve functional recovery in patients with ischemic heart disease. Adjunctive mesenchymal stem cell therapy has been shown to induce PGC1-alpha signaling in hibernating myocardium and could help improve clinical outcomes for patients undergoing bypass surgery.
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Affiliation(s)
- Rishav Aggarwal
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Koray N. Potel
- School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast BT9 7BL, UK
| | - Edward O. McFalls
- Division of Cardiology, Richmond VA Medical Center, Richmond, VA 23249-4915, USA
| | - Tammy A. Butterick
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Research, Center for Veterans Research and Education, Minneapolis, MN 55417, USA
| | - Rosemary F. Kelly
- Division of Cardiothoracic Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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Translational large animal model of hibernating myocardium: characterization by serial multimodal imaging. Basic Res Cardiol 2020; 115:33. [PMID: 32291522 DOI: 10.1007/s00395-020-0788-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/02/2020] [Indexed: 01/08/2023]
Abstract
Nonrevascularizable coronary artery disease is a frequent cause of hibernating myocardium leading to heart failure (HF). Currently, there is a paucity of therapeutic options for patients with this condition. There is a lack of animal models resembling clinical features of hibernating myocardium. Here we present a large animal model of hibernating myocardium characterized by serial multimodality imaging. Yucatan minipigs underwent a surgical casein ameroid implant around the proximal left anterior descending coronary artery (LAD), resulting in a progressive obstruction of the vessel. Pigs underwent serial multimodality imaging including invasive coronary angiography, cardiac magnetic resonance (CMR), and hybrid 18F-Fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT). A total of 43 pigs were operated on and were followed for 120 ± 37 days with monthly multimodality imaging. 24 pigs (56%) died during the follow-up. Severe LAD luminal stenosis was documented in all survivors. In the group of 19 long-term survivors, 17 (90%) developed left ventricular systolic dysfunction [median LVEF of 35% (IQR 32.5-40.5%)]. In 17/17, at-risk territory was viable on CMR and 14 showed an increased glucose uptake in the at-risk myocardium on 18FDG-PET/CT. The present pig model resembles most of the human hibernated myocardium characteristics and associated heart failure (systolic dysfunction, viable myocardium, and metabolic switch to glucose). This human-like model might be used to test novel interventions for nonrevascularizable coronary artery disease and ischemia heart failure as a previous stage to clinical trials.
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Abstract
PURPOSE OF REVIEW Hibernation is an important and reversible cause of myocardial dysfunction in ischaemic heart failure. RECENT FINDINGS Hibernation is an adaptive process that promotes myocyte survival over maintaining contractile function. It is innate to mammalian physiology, sharing features with physiological hibernation in other species. Advanced imaging methods have reasonable accuracy in identifying hibernating myocardium. Novel superior hybrid methods may provide diagnostic potential. New evidence supports the role of surgical revascularisation in ischaemic heart failure, but the role of viability tests in planning such procedures remains unclear. Research to date has exclusively involved patients with ambulatory heart failure: Investigating the role of hibernation in ADHF is a key avenue for the future. Whilst our understanding of hibernation pathophysiology has improved dramatically, the clinical utility of identifying and targeting hibernation remains unclear.
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Affiliation(s)
- Matthew J Ryan
- The Rayne Institute, St Thomas' Hospital, 4th Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK
| | - Divaka Perera
- The Rayne Institute, St Thomas' Hospital, 4th Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK.
- Cardiovascular Division, King's College London, London, UK.
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Hocum Stone LL, Swingen C, Holley C, Wright C, Chappuis E, Ward HB, McFalls EO, Kelly RF. Magnetic resonance imaging assessment of cardiac function in a swine model of hibernating myocardium 3 months following bypass surgery. J Thorac Cardiovasc Surg 2016; 153:582-590. [PMID: 27939502 DOI: 10.1016/j.jtcvs.2016.10.089] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/16/2016] [Accepted: 10/07/2016] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Clinical studies demonstrate delayed recovery of hibernating myocardium (HM) following coronary artery bypass graft (CABG) surgery. Cardiac magnetic resonance (CMR) imaging is effective in identifying HM in clinical settings. Our animal model of HM shows partial but incomplete functional recovery 1 month following CABG using echocardiography. This study uses CMR imaging to determine completeness of recovery 3 months post-CABG. METHODS Swine (N = 12) underwent left anterior descending artery (LAD) 1.5-cm constrictor placement creating a territory of HM over 12 weeks. CMR at 12 weeks confirmed hibernation without infarction (N = 12). Off-pump left internal thoracic artery (LITA) to the LAD was performed in 9 animals. Three animals were killed as HM controls. CMR imaging was repeated in revascularized animals before death at 1 (n = 4) or 3 months (n = 5). CMR imaging was performed at baseline and with dobutamine infusion (5 μg/kg/min). RESULTS Twelve weeks after constrictor placement, CMR imaging confirmed viability in LAD region and LAD stenosis in all animals. In HM, wall thickening is reduced at baseline but with contractile reserve present during dobutamine infusion. Following revascularization, CMR imaging confirmed patent LITA graft (n = 9). Analysis of baseline regional function shows incomplete recovery of HM following CABG, with reduced contractile reserve at both 1 and 3 months post-CABG. CONCLUSIONS CMR imaging provides accurate spatial resolution of regional contractile function and confirms the presence of HM at 12 weeks following instrumentation of the LAD. Three months following CABG, partial recovery of HM with contractile reserve is present in the single LAD territory.
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Affiliation(s)
| | - Cory Swingen
- Department of Surgery, University of Minnesota, Minneapolis, Minn
| | | | - Christin Wright
- Department of Surgery, University of Minnesota, Minneapolis, Minn
| | - Erin Chappuis
- Department of Surgery, University of Minnesota, Minneapolis, Minn
| | - Herbert B Ward
- Department of Surgery, University of Minnesota, Minneapolis, Minn
| | - Edward O McFalls
- Cardiology Division, Minneapolis VA Medical Center, Minneapolis, Minn
| | - Rosemary F Kelly
- Department of Surgery, University of Minnesota, Minneapolis, Minn
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Cardiac Strain in a Swine Model of Regional Hibernating Myocardium: Effects of CoQ10 on Contractile Reserve Following Bypass Surgery. J Cardiovasc Transl Res 2016; 9:368-73. [PMID: 27184805 DOI: 10.1007/s12265-016-9696-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/03/2016] [Indexed: 11/27/2022]
Abstract
There is conflicting clinical evidence whether administration of coenzyme Q10 (CoQ10) improves function following coronary artery bypass graft surgery (CABG). Using a swine model of hibernating myocardium, we tested whether daily CoQ10 would improve contractile function by MRI at 4-week post-CABG. Twelve pigs underwent a thoracotomy and had a constrictor placed on the left anterior descending (LAD). At 12 weeks, they underwent off-pump bypass and received daily dietary supplements of either CoQ10 (10 mg/kg/day) or placebo. At 4-week post-CABG, circumferential strain measurements in the hibernating LAD region from placebo and CoQ10 groups were not different and increased to a similar extent with dobutamine (-14.7 ± 0.6 versus -14.8 ± 0.1, respectively (NS)). Post-sacrifice, oxidant stress markers were obtained in the mitochondrial isolates and protein carbonyl in the placebo, and CoQ10 groups were 6.14 ± 0.36 and 5.05 ± 0.32 nmol/mg, respectively (NS). In summary, CoQ10 did not improve contractile reserve or reduce oxidant stress at 4-week post-CABG.
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Page BJ, Banas MD, Suzuki G, Weil BR, Young RF, Fallavollita JA, Palka BA, Canty JM. Revascularization of chronic hibernating myocardium stimulates myocyte proliferation and partially reverses chronic adaptations to ischemia. J Am Coll Cardiol 2015; 65:684-97. [PMID: 25677430 DOI: 10.1016/j.jacc.2014.11.040] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 11/05/2014] [Accepted: 11/11/2014] [Indexed: 12/30/2022]
Abstract
BACKGROUND The time course and extent of recovery after revascularization of viable dysfunctional myocardium are variable. Although fibrosis is a major determinant, myocyte structural and molecular remodeling may also play important roles. OBJECTIVES This study sought to determine whether persistent myocyte loss and/or irreversibility of protein changes that develop in hibernating myocardium have an impact on functional recovery in the absence of infarction. METHODS Swine implanted with a chronic left anterior descending artery (LAD) stenosis to produce hibernating myocardium underwent percutaneous revascularization, with serial functional recovery evaluated for 1 month (n = 12). Myocardial tissue was evaluated to assess myocyte size, nuclear density, and proliferation indexes in comparison with those of normal animals and nonrevascularized controls. Proteomic analysis by 2-dimensional differential in-gel electrophoresis was used to determine the reversibility of molecular adaptations of hibernating myocytes. RESULTS At 3 months, physiological features of hibernating myocardium were confirmed, with depressed LAD wall thickening and no significant infarction. Revascularization normalized LAD flow reserve, with no immediate change in LAD wall thickening. Regional LAD wall thickening slowly improved but remained depressed 1 month post-percutaneous coronary intervention. Surprisingly, revascularization was associated with histological evidence of myocytes re-entering the growth phase of the cell cycle and increases in the number of c-Kit(+) cells. Myocyte nuclear density returned to normal, whereas regional myocyte hypertrophy regressed. Proteomic analysis demonstrated heterogeneous effects of revascularization. Up-regulated stress and cytoskeletal proteins normalized, whereas reduced contractile and metabolic proteins persisted. CONCLUSIONS Delayed recovery of hibernating myocardium in the absence of scar may reflect persistent reductions in the amounts of contractile and metabolic proteins. Although revascularization appeared to stimulate myocyte proliferation, the persistence of small immature myocytes may have contributed to delayed functional recovery.
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Affiliation(s)
- Brian J Page
- UB Clinical and Translational Research Center and Department of Medicine, University at Buffalo, Buffalo, New York
| | - Michael D Banas
- UB Clinical and Translational Research Center and Department of Medicine, University at Buffalo, Buffalo, New York
| | - Gen Suzuki
- UB Clinical and Translational Research Center and Department of Medicine, University at Buffalo, Buffalo, New York
| | - Brian R Weil
- UB Clinical and Translational Research Center and Department of Medicine, University at Buffalo, Buffalo, New York
| | - Rebeccah F Young
- UB Clinical and Translational Research Center and Department of Medicine, University at Buffalo, Buffalo, New York
| | - James A Fallavollita
- UB Clinical and Translational Research Center and Department of Medicine, University at Buffalo, Buffalo, New York; VA Western New York Health Care System, Buffalo, New York
| | - Beth A Palka
- UB Clinical and Translational Research Center and Department of Medicine, University at Buffalo, Buffalo, New York
| | - John M Canty
- UB Clinical and Translational Research Center and Department of Medicine, University at Buffalo, Buffalo, New York; VA Western New York Health Care System, Buffalo, New York; Department of Physiology and Biophysics and Department of Biomedical Engineering, University at Buffalo, Buffalo, New York.
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Holley CT, Long EK, Lindsey ME, McFalls EO, Kelly RF. Recovery of hibernating myocardium: what is the role of surgical revascularization? J Card Surg 2014; 30:224-31. [PMID: 25470424 DOI: 10.1111/jocs.12477] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Myocardial responses to chronic ischemia represent a continuum of adaptations resulting, over time, in a stress-resistant phenotype. One such adaptation, hibernating myocardium (HM), has increased antioxidant capacity that protects against ischemia-induced oxidative stress. Studies have suggested that revascularization alone may not fully restore cardiac function, highlighting the need for targeted therapies to serve as adjuncts to the innate healing process following revascularization. In our review, we discuss current understanding of HM and the recovery process following surgical revascularization, focusing on animal models of HM to understand implications for human patients.
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Bayeva M, Sawicki KT, Butler J, Gheorghiade M, Ardehali H. Molecular and cellular basis of viable dysfunctional myocardium. Circ Heart Fail 2014; 7:680-91. [PMID: 25028350 DOI: 10.1161/circheartfailure.113.000912] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Marina Bayeva
- From the Division of Cardiology, Department of Medicine, Northwestern University School of Medicine, Chicago, IL (M.B., K.T.S., M.G., H.A.); and Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (J.B.)
| | - Konrad Teodor Sawicki
- From the Division of Cardiology, Department of Medicine, Northwestern University School of Medicine, Chicago, IL (M.B., K.T.S., M.G., H.A.); and Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (J.B.)
| | - Javed Butler
- From the Division of Cardiology, Department of Medicine, Northwestern University School of Medicine, Chicago, IL (M.B., K.T.S., M.G., H.A.); and Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (J.B.)
| | - Mihai Gheorghiade
- From the Division of Cardiology, Department of Medicine, Northwestern University School of Medicine, Chicago, IL (M.B., K.T.S., M.G., H.A.); and Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (J.B.)
| | - Hossein Ardehali
- From the Division of Cardiology, Department of Medicine, Northwestern University School of Medicine, Chicago, IL (M.B., K.T.S., M.G., H.A.); and Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (J.B.).
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Holley CT, Duffy CM, Butterick TA, Long EK, Lindsey ME, Cabrera JA, Ward HB, McFalls EO, Kelly RF. Expression of uncoupling protein-2 remains increased within hibernating myocardium despite successful coronary artery bypass grafting at 4 wk post-revascularization. J Surg Res 2014; 193:15-21. [PMID: 25199570 DOI: 10.1016/j.jss.2014.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/23/2014] [Accepted: 08/01/2014] [Indexed: 12/19/2022]
Abstract
BACKGROUND We have previously shown that mitochondrial uncoupling protein-2 (UCP-2) is increased in a swine model of hibernating myocardium (HM). Although UCP-2 reduces oxidant stress, it can promote inefficiency of the electron transport chain. In this study, we tested whether UCP-2 remains increased in revascularized HM (RHM) after coronary artery bypass grafting (CABG). METHODS Seven swine underwent thoracotomy with placement of a constrictor on the left anterior descending artery (LAD). Twelve weeks later, a left internal mammary artery graft was placed on the distal LAD. Four weeks post-CABG, computed tomography angiography documented patent grafts and function. At the terminal study, blood flow to the LAD and remote territories were assessed during high dose dobutamine and mitochondria isolated from both regions for analysis. Comparisons were made to a group of swine with HM who underwent constrictor placement without bypass grafting (n = 4). RESULTS During dobutamine infusion, RHM demonstrated lower blood flows (2.44 ± 0.23 versus 3.43 ± 0.30 mL/min/g; P < 0.05) and reduced wall thickening (33 ± 9% versus 52 ± 13%; P < 0.05) compared with remote regions. RHM had lower respiratory control indices (3.7 ± 0.3 versus 4.3 ± 0.4; P < 0.05) with persistently increased UCP-2 content. CONCLUSIONS Despite patent grafts, RHM demonstrates a submaximal response to dobutamine infusion and increased mitochondrial UCP-2 expression. These data support the notion that recovery of the mitochondria in RHM is delayed early post-CABG and may contribute to impaired oxygen consumption and contractile reserve during catecholamine challenges.
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Affiliation(s)
| | - Cayla M Duffy
- Department of Food Science and Nutrition, University of Minnesota, Minneapolis, MN; Geriatric Research and Clinical Center (GRECC), Minneapolis Veterans Affairs Health Care System (VAHCS), Minneapolis, MN
| | - Tammy A Butterick
- Department of Food Science and Nutrition, University of Minnesota, Minneapolis, MN; Geriatric Research and Clinical Center (GRECC), Minneapolis Veterans Affairs Health Care System (VAHCS), Minneapolis, MN
| | - Eric K Long
- Department of Surgery, University of Minnesota, Minneapolis, MN
| | - Megan E Lindsey
- College of Medicine, University of Minnesota, Minneapolis, MN
| | - Jesús A Cabrera
- Department of Surgery, University of Minnesota, Minneapolis, MN
| | - Herbert B Ward
- Department of Surgery, University of Minnesota, Minneapolis, MN; Department of Cardiothoracic Surgery, Minneapolis VAHCS, Minneapolis, MN
| | | | - Rosemary F Kelly
- Department of Surgery, University of Minnesota, Minneapolis, MN; Department of Surgery, University of Minnesota, Minneapolis, MN.
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Qu J, Young R, Page BJ, Shen X, Tata N, Li J, Duan X, Fallavollita JA, Canty JM. Reproducible ion-current-based approach for 24-plex comparison of the tissue proteomes of hibernating versus normal myocardium in swine models. J Proteome Res 2014; 13:2571-84. [PMID: 24697261 PMCID: PMC4015685 DOI: 10.1021/pr5000472] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Hibernating
myocardium is an adaptive response to repetitive myocardial
ischemia that is clinically common, but the mechanism of adaptation
is poorly understood. Here we compared the proteomes of hibernating
versus normal myocardium in a porcine model with 24 biological replicates.
Using the ion-current-based proteomic strategy optimized in this study
to expand upon previous proteomic work, we identified differentially
expressed proteins in new molecular pathways of cardiovascular interest.
The methodological strategy includes efficient extraction with detergent
cocktail; precipitation/digestion procedure with high, quantitative
peptide recovery; reproducible nano-LC/MS analysis on a long, heated
column packed with small particles; and quantification based on ion-current
peak areas. Under the optimized conditions, high efficiency and reproducibility
were achieved for each step, which enabled a reliable comparison of
24 the myocardial samples. To achieve confident discovery of differentially
regulated proteins in hibernating myocardium, we used highly stringent
criteria to define “quantifiable proteins”. These included
the filtering criteria of low peptide FDR and S/N > 10 for peptide
ion currents, and each protein was quantified independently from ≥2
distinct peptides. For a broad methodological validation, the quantitative
results were compared with a parallel, well-validated 2D-DIGE analysis
of the same model. Excellent agreement between the two orthogonal
methods was observed (R = 0.74), and the ion-current-based
method quantified almost one order of magnitude more proteins. In
hibernating myocardium, 225 significantly altered proteins were discovered
with a low false-discovery rate (∼3%). These proteins are involved
in biological processes including metabolism, apoptosis, stress response,
contraction, cytoskeleton, transcription, and translation. This provides
compelling evidence that hibernating myocardium adapts to chronic
ischemia. The major metabolic mechanisms include a down-regulation
of mitochondrial respiration and an increase in glycolysis. Meanwhile,
cardioprotective and cytoskeletal proteins are increased, while cardiomyocyte
contractile proteins are reduced. These intrinsic adaptations to regional
ischemia maintain long-term cardiomyocyte viability at the expense
of contractile function.
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Affiliation(s)
- Jun Qu
- Department of Pharmaceutical Sciences, ‡Department of Biochemistry, §Department of Medicine, ∥Department of Physiology and Biophysics, ⊥The Center for Research in Cardiovascular Medicine, and #Center for Excellence in Bioinformatics and Life Sciences, State University of New York at Buffalo , Buffalo, New York 14214, United States
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Bravo C, Kudej RK, Yuan C, Yoon S, Ge H, Park JY, Tian B, Stanley WC, Vatner SF, Vatner DE, Yan L. Metabolomic analysis of two different models of delayed preconditioning. J Mol Cell Cardiol 2012; 55:19-26. [PMID: 23127662 DOI: 10.1016/j.yjmcc.2012.10.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 10/13/2012] [Accepted: 10/14/2012] [Indexed: 01/17/2023]
Abstract
Recently we described an ischemic preconditioning induced by repetitive coronary stenosis, which is induced by 6 episodes of non-lethal ischemia over 3 days, and which also resembles the hibernating myocardium phenotype. When compared with traditional second window of ischemic preconditioning using cDNA microarrays, many genes which differed in the repetitive coronary stenosis appeared targeted to metabolism. Accordingly, the goal of this study was to provide a more in depth analysis of changes in metabolism in the different models of delayed preconditioning, i.e., second window and repetitive coronary stenosis. This was accomplished using a metabolomic approach based on liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) techniques. Myocardial samples from the ischemic section of porcine hearts subjected to both models of late preconditioning were compared against sham controls. Interestingly, although both models involve delayed preconditioning, their metabolic signatures were radically different; of the total number of metabolites that changed in both models (135 metabolites) only 7 changed in both models, and significantly more, p<0.01, were altered in the repetitive coronary stenosis (40%) than in the second window (8.1%). The most significant changes observed were in energy metabolism, e.g., phosphocreatine was increased 4 fold and creatine kinase activity increased by 27.2%, a pattern opposite from heart failure, suggesting that the repetitive coronary stenosis and potentially hibernating myocardium have enhanced stress resistance capabilities. The improved energy metabolism could also be a key mechanism contributing to the cardioprotection observed in the repetitive coronary stenosis and in hibernating myocardium. This article is part of a Special Issue entitled "Focus on Cardiac Metabolism".
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Affiliation(s)
- Claudio Bravo
- Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA
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Jameel MN, Li Q, Mansoor A, Xiong Q, Swingen C, Zhang J. Long-term preservation of myocardial energetic in chronic hibernating myocardium. Am J Physiol Heart Circ Physiol 2010; 300:H836-44. [PMID: 21131472 DOI: 10.1152/ajpheart.00540.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We previously reported that the myocardial energetic state, as defined by the ratio of phosphocreatine to ATP (PCr/ATP), was preserved at baseline (BL) in a swine model of chronic myocardial ischemia with mild reduction of myocardial blood flow (MBF) 10 wk after the placement of an external constrictor on the left anterior descending coronary artery. It remains to be seen whether this stable energetic state is maintained at a longer-term follow-up. Hibernating myocardium (HB) was created in minipigs (n = 7) by the placement of an external constrictor (1.25 mm internal diameter) on the left anterior descending coronary artery. Function was assessed with MRI at regular intervals until 6 mo. At 6 mo, myocardial energetic in the HB was assessed by (31)P-magnetic resonance spectrometry and myocardial oxygenation was examined from the deoxymyoglobin signal using (1)H-magnetic resonance spectrometry during BL, coronary vasodilation with adenosine, and high cardiac workload with dopamine and dobutamine (DpDb). MBF was measured with radiolabeled microspheres. At BL, systolic thickening fraction was significantly lower in the HB compared with remote region (34.4 ± 9.4 vs. 50.1 ± 10.7, P = 0.006). This was associated with a decreased MBF in the HB compared with the remote region (0.73 ± 0.08 vs. 0.97 ± 0.07 ml · min(-1) · g, P = 0.03). The HB PCr/ATP at BL was normal. DpDb resulted in a significant increase in rate pressure product, which caused a twofold increase in MBF in the HB and a threefold increase in the remote region. The systolic thickening fraction increased with DpDb, which was significantly higher in the remote region than HB (P < 0.05). The high cardiac workload was associated with a significant reduction in the HB PCr/ATP (P < 0.02), but this response was similar to normal myocardium. Thus HB has stable BL myocardial energetic despite the reduction MBF and regional left ventricular function. More importantly, HB has a reduced contractile reserve but has a similar energetic response to high cardiac workload like normal myocardium.
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Affiliation(s)
- Mohammad Nurulqadr Jameel
- Department of Medicine, University of Minnesota Medical School, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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Severe Mechanical Dyssynchrony Causes Regional Hibernation-Like Changes in Pigs With Nonischemic Heart Failure. J Card Fail 2009; 15:920-8. [DOI: 10.1016/j.cardfail.2009.06.436] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 06/04/2009] [Accepted: 06/08/2009] [Indexed: 10/20/2022]
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Slezak J, Tribulova N, Okruhlicova L, Dhingra R, Bajaj A, Freed D, Singal P. Hibernating myocardium: pathophysiology, diagnosis, and treatment. Can J Physiol Pharmacol 2009; 87:252-65. [PMID: 19370079 DOI: 10.1139/y09-011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Comprehensive management of patients with chronic ischemic disease is a critically important component of clinical practice. Cardiac myocytes have the potential to adapt to limited flow conditions by adjusting contractile function, reducing metabolism, conserving resources, and preserving myocardial integrity to cope with an oxygen and (or) nutrition shortage. A prime metabolic feature of cardiac myocytes affected by chronic ischemia is the return to a fetal gene pattern with predominance of carbohydrates as the substrate for energy. Structural adaptation with multiple intracellular changes is part of the remodeling process in hibernating myocardium. Transmural heterogeneity, which defines the pattern of injury in ventricular cardiomyocytes and the response to chronic ischemia, is a multifactorial process originating from functional, metabolic, and flow differences in subendocardial and subepicardial regions. Autophagy is typically activated in hibernating myocardium and has been identified as a prosurvival mechanism. Chronic ischemia is associated with changes in the number, size, and distribution of gap junctions and may give rise to conduction disturbances and arrhythmogenesis. Differentiation between viable and nonviable myocardium by assessing sensitivity of inotropic reserve is a crucial diagnostic tool that is correlated with the prognosis and outcome for improved contractility after restoration of blood perfusion in afflicted myocardium.Reliable and accurate diagnosis of ischemic, scar, and viable tissues is critical for recover strategies. Although early surgical reinstitution of blood flow is most effective in restoring physiologic function of the hibernating myocardium, several new approaches offer promising alternatives. Among others, vascular endothelial growth factor and fibroblast growth factor-2 (FGF-2), especially its lo-FGF-2 isoform, have been shown to be effective in rapid neovascularization. Substances such as statins, resveratrol, some hormones, and omega-3 fatty acids can improve recovery effect in chronically underperfused hearts. For patients with drug-refractory ischemia, intramyocardial transplantation of stem cells into predefined areas of the heart can enhance vascularization and have beneficial effects on cardiac function. This review of ischemic injury, its heterogeneity, accurate diagnosis, and newer methods of treatment, shows there is much information and tremendous hope for better management of patients with coronary heart disease.
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Affiliation(s)
- Jan Slezak
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Faculty of Medicine, University of Manitoba, Winnipeg, MB, Canada
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Hu Q, Suzuki G, Young RF, Page BJ, Fallavollita JA, Canty JM. Reductions in mitochondrial O(2) consumption and preservation of high-energy phosphate levels after simulated ischemia in chronic hibernating myocardium. Am J Physiol Heart Circ Physiol 2009; 297:H223-32. [PMID: 19395548 DOI: 10.1152/ajpheart.00992.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We performed the present study to determine whether hibernating myocardium is chronically protected from ischemia. Myocardial tissue was rapidly excised from hibernating left anterior descending coronary regions (systolic wall thickening = 2.8 +/- 0.2 vs. 5.4 +/- 0.3 mm in remote myocardium), and high-energy phosphates were quantified by HPLC during simulated ischemia in vitro (37 degrees C). At baseline, ATP (20.1 +/- 1.0 vs. 26.7 +/- 2.1 micromol/g dry wt, P < 0.05), ADP (8.1 +/- 0.4 vs. 10.3 +/- 0.8 micromol/g, P < 0.05), and total adenine nucleotides (31.2 +/- 1.3 vs. 40.1 +/- 2.9 micromol/g, P < 0.05) were depressed compared with normal myocardium, whereas total creatine, creatine phosphate, and ATP-to-ADP ratios were unchanged. During simulated ischemia, there was a marked attenuation of ATP depletion (5.6 +/- 0.9 vs. 13.7 +/- 1.7 micromol/g at 20 min in control, P < 0.05) and mitochondrial respiration [145 +/- 13 vs. 187 +/- 11 ng atoms O(2).mg protein(-1).min(-1) in control (state 3), P < 0.05], whereas lactate accumulation was unaffected. These in vitro changes were accompanied by protection of the hibernating heart from acute stunning during demand-induced ischemia. Thus, despite contractile dysfunction at rest, hibernating myocardium is ischemia tolerant, with reduced mitochondrial respiration and slowing of ATP depletion during simulated ischemia, which may maintain myocyte viability.
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Affiliation(s)
- Qingsong Hu
- Center for Research in Cardiovascular Medicine, University at Buffalo, Buffalo, NY 14214, USA
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