Permanent Ligation av Venstre Anterior Synkende Coronary Artery i Mus: En modell av Post-hjerteinfarkt Remodelling og hjertesvikt
Summary
Heart failure is the leading cause of hospitalization and a major cause of mortality. A model of permanent ligation of the left anterior descending coronary artery in mice is applied to investigate ventricular remodelling and cardiac dysfunction post-myocardial infarction. The technique of invasive hemodynamic measurements in mice is presented.
Abstract
Hjertesvikt er et syndrom der hjertet ikke klarer å pumpe blod med en hastighet i samsvar med mobilnettet oksygenbehov ved hvile eller under stress. Det er preget av væskeretensjon, kortpustethet, og tretthet, særlig ved anstrengelse. Hjertesvikt er et økende folkehelseproblem, den ledende årsak til sykehusinnleggelse, og en viktig årsak til dødelighet. Iskemisk hjertesykdom er den viktigste årsaken til hjertesvikt.
Ventrikulær ombygging refererer til endringer i strukturen, størrelsen og formen av den venstre ventrikkel. Dette arkitektoniske ombygging av venstre ventrikkel indusert av skade (for eksempel hjerteinfarkt), ved hjelp av trykk overbelastning (for eksempel, systemisk arteriell hypertensjon eller aortastenose), eller ved væskeoverskudd. Siden ventrikkel ombygging påvirker vegg stress, har det en betydelig innflytelse på hjertefunksjon og på utvikling av hjertesvikt. En modell med permanent ligering av den venstre fremre descending koronar i mus brukes til å undersøke ventrikkel ombygging og hjertefunksjon etter hjerteinfarkt. Denne modellen er fundamentalt annerledes i form av mål og patofysiologisk relevans i forhold til modellen av forbigående ligation av venstre fremre nedstigende coronary artery. I denne sistnevnte modell av iskemi / reperfusjonsskade, kan den initiale grad av infarkt bli modulert ved faktorene som påvirker myokardial berging etter reperfusjon. I motsetning til dette er det infarktområdet på 24 timer etter permanent ligering av den venstre fremre nedadstigende koronararterie fast. Hjertefunksjon i denne modellen vil bli påvirket av 1) prosessen med infarkt ekspansjon, infarktet healing, og arrdannelse; og 2) samtidig utvikling av venstre ventrikkel dilatasjon, hjertehypertrofi, og ventrikkel ombygging.
Foruten den modell med permanent ligering av den venstre fremre nedadstigende koronararterie, teknikken for invasiv hemodynamisk measurements i mus er presentert i detalj.
Introduction
Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with the cellular oxygen requirements at rest or during stress. It is characterized by fluid retention, shortness of breath, and fatigue, in particular on exertion. Heart failure is a growing public health problem, the leading cause of hospitalization, and a major cause of mortality. Ischemic heart disease is the main cause of heart failure1.
Ventricular remodelling refers to changes in structure, size, and shape of the left ventricle. In other words, ventricular remodelling concerns an alteration of the left ventricular architecture. This architectural remodelling of the left ventricle is induced by injury (e.g., myocardial infarction), by pressure overload (e.g., systemic arterial hypertension or aortic stenosis), or by volume overload (e.g., mitral insufficiency). Since ventricular remodelling affects wall stress, it has a profound impact on cardiac function and on the development of heart failure.
Loss of myocardial tissue following acute myocardial infarction results in a decreased systolic ejection and an increased left ventricular end-diastolic volume and pressure. The Frank-Starling mechanism, implying that an increased end-diastolic volume results in an increased pressure developed during systole, may help to restore cardiac output. However, the concomitant increased wall stress may induce regional hypertrophy in the non-infarcted segment, whereas in the infarcted area expansion and thinning may occur. Experimental animal studies show that the infarcted ventricle hypertrophies and that the degree of hypertrophy is dependent on the infarct size2.
The loss of myocardial tissue following acute myocardial infarction results in a sudden increase in loading conditions. Post-infarct remodelling occurs in the setting of volume overload, since the stretched and dilated infarcted tissue increases the left ventricular volume. An increased ventricular volume not only implies increased preload (passive ventricular wall stress at the end of diastole) but also increased afterload (total myocardial wall stress during systolic ejection). Afterload is increased since the systolic radius is increased. Therefore, ventricular remodelling post-myocardial infarction is characterized by mixed features of volume overload and pressure overload.
The myocardium consists of 3 integrated components: cardiomyocytes, extracellular matrix, and the capillary microcirculation. All 3 components are involved in the remodelling process. Matrix metalloproteinases produced by inflammatory cells induce degradation of intermyocyte collagen struts and cardiomyocyte slippage. This leads to infarct expansion characterized by the disproportionate thinning and dilatation of the infarct segment3. In later stages of remodelling, interstitial fibrosis is induced, which negatively affects the diastolic properties of the heart.
The vascular and cardiomyocyte compartment in the myocardium should remain balanced in the process of ventricular remodelling to avoid tissue hypoxia4,5. Whether hypertrophy progresses to heart failure or not may be critically dependent on this balance between the vascular and cardiomyocyte compartment in the myocardium.
A model of permanent ligation of the left anterior descending coronary artery in mice is used to investigate ventricular remodelling and cardiac function post-myocardial infarction. This model is fundamentally different in terms of objectives and pathophysiological relevance compared to the model of transient ligation of the left anterior descending coronary artery. In this latter model of ischemia/reperfusion injury, the initial extent of the infarct may be modulated by factors that affect myocardial salvage following reperfusion6. In contrast, the infarct area at 24 hours after permanent ligation of the left anterior descending coronary artery is fixed. Cardiac function in this model will be affected by 1) the process of infarct expansion, infarct healing, and scar formation; and 2) the concomitant development of left ventricular dilatation, cardiac hypertrophy, and ventricular remodelling.
Protocol
Representative Results
Discussion
Kroniske endringer i myocardial struktur og funksjon, kan utviklingen av venstre ventrikkel dysfunksjon, og progresjon til hjertesvikt bli undersøkt i flere murine modeller 12. Cardiac ombygging og dysfunksjon kan være forårsaket av skade på hjertet eller ved trykk overbelastning sekundært til tverrgående aorta innsnevring, eller kan bli undersøkt i genetiske modeller av dilatert kardiomyopati 12. Selvsagt, den mest uttalt fordel for murine modeller er tilgjengeligheten av et stort antall tr…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
This work was supported by Onderzoekstoelagen grant OT/13/090 of the KU Leuven and by grant G0A3114N of the FWO-Vlaanderen.
Materials
| Reagents | |||
| Buprenorphine (Buprenex®) | Bedford Laboratories | ||
| Sodium Pentobarbital (Nembutal®) | Ceva | ||
| Betadine® | VWR internationals | 200065-400 | |
| 5 – 0 silk suture | Ethicon, Johnson & Johnson Medical | K890H | |
| 6 – 0 prolene suture | Ethicon, Johnson & Johnson Medical | F1832 | |
| 6 – 0 Ti- Cron suture | Ethicon, Johnson & Johnson Medical | F1823 | |
| Urethane | Sigma | 94300 | |
| Alconox | Alconox Inc. | ||
| Equipment | |||
| Ventilator, MiniVent Model 845 | Hugo Sachs | 73-0043 | |
| Chest retractor or Thorax retractor | Kent Scientific corporation | INS600240 | ALM Self-retaining, serrated, 7cm long, 4 x 4 "L" shaped prongs, 3mm x 3mm |
| 1.0 French Millar pressure catheter | Millar Instruments | SPR – 1000/NR | |
| Powerlab | ADInstruments Pty Ltd. | ||
| LabChart® software | ADInstruments Pty Ltd. | ||
| Rectal probe | ADInstruments Pty Ltd. |
Riferimenti
- He, J., et al. Risk factors for congestive heart failure in US men and women: NHANES I epidemiologic follow-up study. Arch Intern Med. 161, 996-1002 (2001).
- Anversa, P., Sonnenblick, E. H. Ischemic cardiomyopathy: pathophysiologic mechanisms. Prog Cardiovasc Dis. 33, 49-70 (1990).
- Erlebacher, J. A., Weiss, J. L., Weisfeldt, M. L., Bulkley, B. H. Early dilation of the infarcted segment in acute transmural myocardial infarction: role of infarct expansion in acute left ventricular enlargement. J Am Coll Cardiol. 4, 201-208 (1984).
- Shimizu, I., et al. Excessive cardiac insulin signaling exacerbates systolic dysfunction induced by pressure overload in rodents. J Clin Invest. 120, 1506-1514 (2010).
- Tirziu, D., et al. Myocardial hypertrophy in the absence of external stimuli is induced by angiogenesis in mice. J Clin Invest. 117, 3188-3197 (2007).
- Theilmeier, G., et al. High-density lipoproteins and their constituent, sphingosine-1-phosphate, directly protect the heart against ischemia/reperfusion injury in vivo via the S1P3 lysophospholipid receptor. Circulation. 114, 1403-1409 (2006).
- Weiss, J. L., Frederiksen, J. W., Weisfeldt, M. L. Hemodynamic determinants of the time-course of fall in canine left ventricular pressure. J Clin Invest. 58, 751-760 (1976).
- Bohl, S., et al. Refined approach for quantification of in vivo ischemia-reperfusion injury in the mouse heart. Am J Physiol Heart Circ Physiol. 297, 2054-2058 (2009).
- Van Craeyveld, E., Jacobs, F., Gordts, S. C., De Geest, B. Low-density lipoprotein receptor gene transfer in hypercholesterolemic mice improves cardiac function after myocardial infarction. Gene Ther. 19, 860-871 (2012).
- Gordts, S. C., et al. Beneficial effects of selective HDL-raising gene transfer on survival, cardiac remodelling and cardiac function after myocardial infarction in mice. Gene Ther. 20, 1053-1061 (2013).
- Junqueira, L. C., Bignolas, G., Brentani, R. R. Picrosirius staining plus polarization microscopy, a specific method for collagen detection in tissue sections. Histochem J. 11, 447-455 (1979).
- Patten, R. D., Hall-Porter, M. R. Small animal models of heart failure: development of novel therapies, past and present. Circ Heart Fail. 2, 138-144 (2009).
- Zolotareva, A. G., Kogan, M. E. Production of experimental occlusive myocardial infarction in mice. Cor Vasa. 20, 308-314 (1978).
- Michael, L. H., et al. Myocardial ischemia and reperfusion: a murine model. Am J Physiol. 269, 2147-2154 (1995).
- Salto-Tellez, M., et al. Myocardial infarction in the C57BL/6J mouse: a quantifiable and highly reproducible experimental model. Cardiovasc Pathol. 13, 91-97 (2004).
- Fernandez, B., et al. The coronary arteries of the C57BL/6 mouse strains: implications for comparison with mutant models. J Anat. 212, 12-18 (2008).
- Kumar, D., et al. Distinct mouse coronary anatomy and myocardial infarction consequent to ligation. Coron Artery Dis. 16, 41-44 (2005).
- Clauss, S. B., Walker, D. L., Kirby, M. L., Schimel, D., Lo, C. W. Patterning of coronary arteries in wildtype and connexin43 knockout mice. Dev Dyn. 235, 2786-2794 (2006).
- Icardo, J. M., Colvee, E. Origin and course of the coronary arteries in normal mice and in iv/iv mice. J Anat. 199, 473-482 (2001).
- Yoldas, A., Ozmen, E., Ozdemir, V. Macroscopic description of the coronary arteries in Swiss albino mice (Mus musculus). J S Afr Vet Assoc. 81, 247-252 (2010).
- James, T. N., Burch, G. E. Blood supply of the human interventricular septum. Circulation. 17, 391-396 (1958).
- Gao, X. M., Xu, Q., Kiriazis, H., Dart, A. M., Du, X. J. Mouse model of post-infarct ventricular rupture: time course, strain- and gender-dependency, tensile strength, and histopathology. Cardiovasc Res. 65, 469-477 (2005).
- Muthuramu, I., Jacobs, F., Singh, N., Gordts, S. C., De Geest, B. Selective homocysteine lowering gene transfer improves infarct healing, attenuates remodelling, and enhances diastolic function after myocardial infarction in mice. PLoS One. 8, 63710 (2013).
- Eaton, L. W., Weiss, J. L., Bulkley, B. H., Garrison, J. B., Weisfeldt, M. L. Regional cardiac dilatation after acute myocardial infarction: recognition by two-dimensional echocardiography. N Engl J Med. 300, 57-62 (1979).
- Erlebacher, J. A., et al. Late effects of acute infarct dilation on heart size: a two dimensional echocardiographic study. Am J Cardiol. 49, 1120-1126 (1982).
- Schuster, E. H., Bulkley, B. H. Expansion of transmural myocardial infarction: a pathophysiologic factor in cardiac rupture. Circulation. 60, 1532-1538 (1979).
- Jugdutt, B. I., Michorowski, B. L. Role of infarct expansion in rupture of the ventricular septum after acute myocardial infarction: a two-dimensional echocardiographic study. Clin Cardiol. 10, 641-652 (1987).
- Pacher, P., Nagayama, T., Mukhopadhyay, P., Batkai, S., Kass, D. A. Measurement of cardiac function using pressure-volume conductance catheter technique in mice and rats. Nat Protoc. 3, 1422-1434 (2008).
- Vanden Bergh, A., Flameng, W., Herijgers, P. Parameters of ventricular contractility in mice: influence of load and sensitivity to changes in inotropic state. Pflugers Arch. 455, 987-994 (2008).
