In vivo heat shock preconditioning mitigates calcium overload during ischaemia/reperfusion in the isolated, perfused rat heart

• Published in: Pflügers Archiv 2005-03, Vol.449 (6), p.518-525
• Main Authors: Szenczi, Orsolya, Kemecsei, Péter, Miklós, Zsuzsanna, Ligeti, László, Snoeckx, Luc H E H, van Riel, Natal A W, Op den Buijs, Jorn, Van der Vusse, Ger J, Ivanics, Tamás
• Format: Article
• Language: English
• Subjects: Animals; Calcium - metabolism; Diastole - physiology; Heart - physiology; Heat-Shock Response - physiology; HSP70 Heat-Shock Proteins - metabolism; Ischemic Preconditioning; Male; Myocardium - metabolism; Rats; Rats, Sprague-Dawley; Reperfusion Injury - metabolism; Reperfusion Injury - physiopathology; Reperfusion Injury - prevention & control; Rodents; Ventricular Pressure - physiology
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/s00424-004-1358-2

Heat shock (HS) pretreatment of the heart is effective in mitigating the deleterious effects of ischaemia/reperfusion. The main objective of this study was to determine whether the beneficial effect of HS is associated with the preservation of intracellular Ca2+ handling in the ischaemic/reperfused, isolated rat heart. Twenty-four hours after raising body core temperature to 42 degrees C for 15 min, rat hearts were perfused according to Langendorff and subjected to 30 min ischaemia followed by 20 min reperfusion. Cyclic changes of cytoplasmic calcium ion [Ca2+i] levels were measured by surface fluorometry using Indo-1 AM. Reperfused HS hearts showed improved recovery of contractile function compared with control hearts: end-diastolic pressure: 45+/-11 vs. 64+/-22 mmHg; developed pressure: 72+/-12 vs. 41+/-20 mmHg; maximum rate of pressure increase (+dP/dtmax): 1,513+/-305 vs. 938+/-500 mmHg/s; maximum rate of pressure decrease (-dP/dtmax): -1,354+/-304 vs. -806+/-403 mmHg/s. HS hearts displayed a significantly lower end-diastolic cytosolic [Ca2+] ([Ca2+]i) after reinstallation of flow. The dynamic parameters of the Ca2+i transients, i.e. the maximum rate of increase/decrease (+/-dCa2+i/dtmax) and amplitude, did not differ between reperfused control and HS hearts. The novel finding of this study is that improved performance of the HS-preconditioned heart after an ischaemic insult is associated with a reduced end-diastolic Ca2+i load, and most likely, preserved Ca2+ sensitivity of the myocardial contractile machinery.