The Protective Effect of Heat Stress Against Reperfusion Arrhythmias in the Rat

Steare, S.E.; Yellon, Derek M.

doi:10.1006/jmcc.1993.1163

Cited by 49 publications

(29 citation statements)

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“…Although the precise role of HSP27 in cardiac neurons is unclear, it may aid in axonal transport and synaptic function 27,28 and could act to protect or stabilize neuronal function after ischemia, possibly helping to suppress arrhythmias. 29,30 In contrast to the pattern of HSP27 labeling, HSP70-IR was not detected in the intracardiac nervous system either in control hearts or after heat shock. Thus, HSP70 appears not to have a role in neural control of the heart on an ongoing basis, or after heat shock.…”

Section: Discussionmentioning

confidence: 93%

Confocal Microscopic Localization of Constitutive and Heat Shock–Induced Proteins HSP70 and HSP27 in the Rat Heart

2000

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Background-Heat-shock treatment of rats elevates expression of heat-shock proteins, which play a role in improving the contractile recovery and reducing infarct size in hearts after ischemic injury. However, the location of these proteins in the heart is unknown. Methods and Results-Anesthetized rats were heat-shocked by elevation of body temperature to 42°C to 42.5°C for 15 minutes, followed by 24 hours of recovery. Control and heat-shocked hearts were extirpated and perfused briefly with saline followed by 2% paraformaldehyde in PBS. Confocal immunofluorescence microscopy of control hearts revealed that HSP27 was localized in cardiomyocytes in a pattern reminiscent of Z bands and was colocalized with neuronal markers in somata and axons. No obvious change in HSP27 content or distribution occurred after heat shock. Confocal microscopy revealed little or no HSP70 in control hearts. After heat shock, HSP70 was detected neither in cardiomyocytes nor in neuronal elements within the heart, but HSP70 was abundant in small blood vessels found between the ventricular cardiomyocytes. Conclusions-Heat shock induces a cell type-specific expression of HSP70 in blood vessels but not myocytes or intrinsic cardiac neurons, suggesting that blood vessels play a primary role in myocardial protection. (Circulation.

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Section: Discussionmentioning

confidence: 93%

Confocal Microscopic Localization of Constitutive and Heat Shock–Induced Proteins HSP70 and HSP27 in the Rat Heart

2000

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“…After 24 h of brief heat stress or brief repeated ischemia (stress pretreatment), overexpression of HSP72 in the myocardium reduced infarct size [2][3][4] and improved contractile function 5,6 following sublethal ischemia. Significantly improved global left ventricular hemodynamic performance, 7 reduced loss of intracellular enzymes, 8 and a diminution of the duration of arrhythmias 9 compared to non-pretreated controls were also observed. However, most studies of HSP72 have focused on stresspretreated hearts and the protective role of overexpression of HSP72 in the ischemic heart has been demonstrated following a short period of ischemia.…”

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confidence: 74%

Time Course of Expression and Localization of Heat Shock Protein 72 in the Ischemic and Reperfused Rat Heart

Yokoyama

Asano

1999

Jpn Circ J

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SP70 proteins are central components of the cellular chaperone system associated with folding, assembly, disassembly and degradation of proteins. 1 During the last decade, a number of studies have suggested that stress-induced overexpression of HSP72 may confer protection against ischemia and reperfusion injury in the heart. After 24 h of brief heat stress or brief repeated ischemia (stress pretreatment), overexpression of HSP72 in the myocardium reduced infarct size 2-4 and improved contractile function 5,6 following sublethal ischemia. Significantly improved global left ventricular hemodynamic performance, 7 reduced loss of intracellular enzymes, 8 and a diminution of the duration of arrhythmias 9 compared to non-pretreated controls were also observed. However, most studies of HSP72 have focused on stresspretreated hearts and the protective role of overexpression of HSP72 in the ischemic heart has been demonstrated following a short period of ischemia. The expression of HSP72 in the non-stress-pretreated heart in the course of ischemia and reperfusion, which would resemble clinical myocardial ischemia and reperfusion, requires investigation. It is still unclear when and where HSP72 reaches its maximum expression, for how long HSP72 expression is sustained, and whether HSP72 expression relates to morphological changes through a permanent ischemia or reperfusion process. Therefore, we observed the time course of expression and localization of HSP72 in nonstress-pretreated hearts, using in vivo coronary artery occlusion and reperfusion rat models. We believe that this study may contribute to understanding of the role of HSP72 in ischemic heart disease. Materials and MethodsAll studies were performed in accordance with to the "Guide for the Care and Use of Laboratory Animals" published by the US National Institutes of Health (NIH publication No 85-23, revised in 1985) and were approved by the Animal Experimentation Committee of Nippon Medical School. Surgical ProceduresRat models of myocardial ischemia and reperfusion were employed as previously described. [10][11][12] Male Wistar rats weighing 250 to 300 g (Sankyou Laboratory Supplies, Tokyo, Japan) were anesthetized intraperitoneally with sodium pentobarbital (30 mg/kg body weight), tracheostomized and ventilated on a rodent respirator (Model 681, Harvard instruments). Intermittent positive pressure ventilation was given with a mixture of 95% oxygen and 5% carbon dioxide (1 ml/100 g body weight, 65 strokes/ min). A thoracotomy was performed via the left fourth intercostal space, and after pericardiotomy, the left main coronary artery was occluded near its origin with 5-0 nylon sutures, then the chest was closed. Piperacillin sodium (100 mg) was administered intramuscularly. Myocardial ischemic changes were confirmed by electrocardiogram findings (ST segment elevation) and by the pale color of the left ventricular surface as observed macroscopically. Reperfusion was performed as previously described. 12 The 4-0 cotton suture was released after 30 min of occlusi...

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“…The cardioprotective effects of preconditioning are κ-OR mediated since the effects on both cardiac protection and expression of HSP 70 are blocked by a selective antagonist, nor-binaltorphimine (nor-BNI) [24]. In rats made diabetic by streptozotocin (STZ), heat stress, which confers cardioprotection in normal rats [6,17], fails to do so [8]. On the other hand, the treatment still induces heat-shock protein in diabetic rats as it does in normal rat [8].…”

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confidence: 99%

Failure to confer cardioprotection and to increase the expression of heat-shock protein 70 by preconditioning with a ?-opioid receptor agonist during ischaemia and reperfusion in streptozotocin-induced diabetic rats

Kam

Chen

et al. 2004

Diabetologia

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Aims/hypothesis. The aim of this study was to determine the effects of preconditioning on injury and expression of heat shock proteins 70 in diabetic rat hearts. Methods. Diabetes was induced by an intraperitoneal injection of 65 mg kg −1 streptozotocin. Daily subcutaneous injection of 4 IU insulin started 2 weeks after streptozotocin treatment for 4 weeks. Rats were preconditioned by intravenous injection of 10 mg kg −1 U50,488H, a selective κ-opioid receptor agonist (U50,488H preconditioning). The effects of U50,488H preconditioning had previously been shown to be blocked by a selective κ-opioid receptor antagonist, nor-binaltorphimine. Twenty-four hours later, rats were subjected to 30 min of regional ischaemia by occlusion of the left coronary artery followed by 4 h of reperfusion. Infarct size was determined at the end of reperfusion. Stress-inducible and constitutive heat shock proteins 70 were analysed at the end of ischaemia and reperfusion by Western blotting.Results. Myocardial infarcts induced by ischaemia and reperfusion were greater in diabetic rats. U50,488H preconditioning significantly reduced the infarct size and increased the expression of stress-inducible heatshock protein 70 in normal rats. The effects of U50,488H preconditioning were abolished in streptozotocin-induced diabetic rats, but restored by insulin replacement. Conclusion/interpretation. In addition to a greater susceptibility to ischaemic insults, the delayed cardioprotection of U50,488H preconditioning was lost, which could at least partly be due to impaired synthesis of stress-inducible heat-shock protein 70 in diabetic rats. [Diabetologia (2004) 47:214-220] Keywords U50,488H preconditioning · κ-opioid receptor · Streptozotocin · Diabetic rats · Ischaemia and reperfusion · Cardioprotection stress inducible heat shock protein 70

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The Protective Effect of Heat Stress Against Reperfusion Arrhythmias in the Rat

Cited by 49 publications

References 0 publications

Confocal Microscopic Localization of Constitutive and Heat Shock–Induced Proteins HSP70 and HSP27 in the Rat Heart

Confocal Microscopic Localization of Constitutive and Heat Shock–Induced Proteins HSP70 and HSP27 in the Rat Heart

Time Course of Expression and Localization of Heat Shock Protein 72 in the Ischemic and Reperfused Rat Heart

Failure to confer cardioprotection and to increase the expression of heat-shock protein 70 by preconditioning with a ?-opioid receptor agonist during ischaemia and reperfusion in streptozotocin-induced diabetic rats

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