Acute post-ischaemic ventricular changes: role of microcirculatory trouble and myocardial oedema in isolated working rat hearts

Journal of Clinical and Basic Cardiology 1999; 2 (2): 267-274

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Keywords: Endothel,  fibronectin,  mikrovaskuläre Permeabilität,  Reperfusionsschaden,  Reperfusionsödem,  endothelium,  fibronectin,  microvascular permeability,  reperfusion injury,  reperfusion oedema

Acute postischaemic ventricular changes are characterized by ventricular wall alterations, involving both ischaemic and not-ischaemic segments of the ventricle. These changes include either myocytic or interstitial structural damage and/or rearrangement. One of the consequences of myocardial ischaemia is the development of interstitial and intracellular oedema, which results in an increase of wall tension, plugging of the microcirculation and ventricular remodeling. In this study we have detected the effects of post-ischaemic microcirculatory permeability changes on ventricular function and myocytic or interstitial structural damage and/or rearrangement. We have evaluated the effects of reperfusion-induced oedema on acute ventricular changes and mechanical function in isolated working rat hearts. After 15 min. of global ischaemia, hearts were perfused with isotonic Krebs-Henseleit (iKH, 287 mOsm) or with hypertonic KH (hKH, obtained by adding 80 mM sucrose to KH, 320 mOsm) to reduce reperfusion-induced oedema. Acute ventricular changes were evaluated in terms of haemodynamic parameters, enzyme release, heart weight, myocyte damage (immunoperoxidase labelled anti-lactic dehydrogenase antibodies), cellular fibronectin deposition and rearrangement (immunoperoxidase labelled antifibronectin antibodies), endothelial permeability (fluorescein isothiocyanate-albumin immunofluorescence). An ultrastructural examination was also performed to determine cellular (mitochondria, fibrils) and interstitial damage. In isotonic-perfused hearts all functional parameters were significantly reduced. This was concomitant with a significant increase of myocyte damage, endothelium permeability and c-fibronectin deposition in perivascular space. These changes were related to myocardial oedema; hypertonic reperfusion of the hearts resulted in a significant protection. These data indicate that, in isolated working rat hearts, there is a close relationship between reperfusion-induced oedema and acute ventricular changes, involving myocyte damage and interstitial matrix rearrangement. J Clin Basic Cardiol 1999; 2: 267-74.