HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Magdi H. Yacoub Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gray, C. C. Articles by Yacoub, M. H. Search for Related Content PubMed PubMed Citation Articles by Gray, C. C. Articles by Yacoub, M. H. Related Collections Cardiac - physiology

J Thorac Cardiovasc Surg 2001;121:1130-1136
© 2001 The American Association for Thoracic Surgery

Surgery for Acquired Cardiovascular Disease

Cold cardioplegic arrest enhances heat shock protein 70 in the heat-shocked rat heart

From the Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College, Harefield Hospital, Harefield, Middlesex, United Kingdom.

Received for publication July 18, 2000. Revisions requested Sept 14, 2000; revisions received Oct 23, 2000. Accepted for publication Nov 28, 2000. Address for reprints: M. Amrani, MD, PhD, Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College, Harefield Hospital, Harefield, Middlesex, UB9 6JH, United Kingdom.

Background: Myocardial content of the 70-kd heat shock protein has been found to correlate with improved cardiac recovery after ischemia, but the mechanisms and conditions that regulate its level, particularly under clinical conditions, are unclear. The aim of this study was to assess the effect of hypothermic cardioplegic arrest and reperfusion on the expression of 70-kd heat shock protein in a protocol mimicking conditions of preservation for cardiac transplantation.
Methods: Heat-shocked and control hearts were subjected to 4 hours of cardioplegic arrest and global ischemia at 4°C and then to 20 minutes of reperfusion. Hearts were freeze clamped at different time points—after 15 minutes of Langendorff perfusion, at the end of ischemia, and after 20 minutes of reperfusion, and analyzed for heat shock protein 70 content by Western blotting. Another set of hearts was subjected to 10 minutes of normothermic ischemia and 20 minutes of reperfusion followed by freeze clamping and analysis of heat shock protein 70 content as in cardioplegic arrest protocol. Cardiac function was measured by means of a left ventricular balloon at the end of reperfusion.
Results: Preischemic concentration of 70-kd heat shock protein was increased in heat-shocked hearts compared with control hearts. The content of 70-kd heat shock protein in heat-shocked hearts was further increased from 5.0 ± 2.4 ng/µg at the end of ischemia to 11.0 ± 4.9 ng/µg (n = 8, mean ± SD; P < .05) at 20 minutes of reperfusion after cold cardioplegic arrest. No further rise in 70-kd heat shock protein of the heat-shocked hearts was observed after normothermic ischemia. Maximal developed pressure was 120.8 ± 13.4 mm Hg in control hearts compared with 164.7 ± 22.5 mm Hg in heat-shocked hearts (n = 5, mean ± SD; P = .037) after cardioplegic arrest. By contrast, after normothermic ischemia, maximum developed pressure was 111.2 ± 10.9 mm Hg in control hearts compared with 139.2 ± 11.0 mm Hg in heat-shocked hearts (n = 4, mean ± SD; P = .031).
Conclusion: Hypothermic cardioplegic arrest but not short normothermic ischemia triggered a further increase in the level of 70-kd heat shock protein in heat-shocked rat hearts, which may enhance endogenous cardiac protection.