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Background: Increased activated Akt and eNOS expression coincide with this persistent cardioprotection. Emergent coronary reperfusion therapies are rarely carried out before considerable myocardial injury has occurred. Moreover, reperfusion after prolonged ischemia produces paradoxical ischemia-reperfusion injury, attenuating the efficacy of reperfusion therapies. This has provided impetus for identifying chronic therapies to protect against ischemia-reperfusion injury in those at risk. We previously found that regular dipyridamole therapy produces a chronic preconditioning-like effect mediated through adenosine A1 receptors. Methods: To determine how long this chronic preconditioning effect of dipyridamole remains present after discontinuing therapy, guinea pigs received 4 mg/kg/day in their water for 6 weeks. Ischemia-reperfusion was performed at 0, 2, 3, and 4 days after dipyridamole discontinuation (0 day, 2 days, 3 days and 4 days; n = 8 per group). Left ventricular developed pressure (LVDP), end-diastolic pressure (LVEDP), coronary flow (CF), infarct size, and western blot analyses for Akt and endothelial nitric oxide synthase (eNOS) were studied. Results: After ischemia-reperfusion, 0 day, 2 days and 3 days, but not 4 days, had significantly higher LVDP and lower LVEDP compared to control. Myocardial infarct size was significantly reduced at 0 day, 2 days and 3 days, but not 4 days, compared to control. Western blot analyses demonstrated upregulation of phospho-Akt and phospho-eNOS expression at 0 day, 2 days, and 3 days, but not 4 days. Conclusions: A chronic preconditioning-like cardioprotection by regular dipyridamole treatment persists for 3 days after discontinuing therapy. Increased activated Akt and eNOS expression may play a role in this persistent cardioprotection. (C) 2014 Elsevier Ireland Ltd. All rights reserved.

Sevoflurane increases reactive oxygen species (ROS), which mediate cardioprotection against myocardial ischemia-reperfusion injury. Emerging evidence suggests that autophagy is involved in cardioprotection. We examined whether reactive oxygen species mediate sevoflurane preconditioning through autophagy. Isolated guinea pigs hearts were subjected to 30 min ischemia followed by 120 min reperfusion (control). Anesthetic preconditioning was elicited with 2 % sevoflurane for 10 min before ischemia (SEVO). The ROS-scavenger, N-(2-mercaptopropionyl) glycine (MPG, 1 mmol/l), was administered starting 30 min before ischemia to sevoflurane-treated (SEVO + MPG) or non-sevoflurane-treated (MPG) hearts. Infarct size was determined by triphenyltetrazolium chloride stain. Tissue samples were obtained after reperfusion to determine autophagy-related protein (microtubule-associated protein light chain I and II: LC3-I, -II) and 5' AMP-activated protein kinase (AMPK) expression using Western blot analysis. Electron microscopy was used to detect autophagosomes. Infarct size was significantly reduced and there were more abundant autophagosomes in SEVO compared with control. Western blot analysis revealed that the ratio of LC3-II/I and phosphorylation of AMPK were significantly increased in SEVO. These effects were abolished by MPG. Sevoflurane induces cardioprotection through ROS-mediated upregulation of autophagy.

Sevoflurane preconditioning against myocardial ischemia-reperfusion injury is lost if the ischemic insult is too long. Emerging evidence suggests that induction of autophagy may also confer cardioprotection against ischemia-reperfusion injury. We examined whether induction of autophagy prolongs sevoflurane preconditioning protection during a longer ischemic insult. Isolated guinea pigs hearts were subjected to 30 or 45 mm ischemia, followed by 120 min reperfusion (control). Anesthetic preconditioning was elicited with 2% sevoflurane for 10 min prior to ischemia (SEVO-30, SEVO-45). Chloramphenicol (autophagy upregulator, 300 mu M) was administered starting 20 min before ischemia and throughout reperfusion in SEVO-45 (SEVO-45 + CAP). To inhibit autophagy, 3-methyladenine (10 mu M) was administered during sevoflurane administration in SEVO-45 + CAR Infarct size was determined by triphenyltetrazolium chloride stain. Tissue samples were obtained before ischemia to determine autophagy-related protein (microtubule-associated protein light chain I and II: LC3-I, II), Ala and glycogen synthase kinase 3 beta (GSK3 beta) expression using Western blot analysis. The effect of autophagy on calcium-induced mitochondrial permeability transition pore (MPTP) opening in isolated calcein-loaded mitochondria was assessed. Electron microscopy was used to detect autophagosomes. Infarct size was significantly reduced in SEVO-30, but not in SEVO-45. Chloramphenicol restored sevoflurane preconditioning lost by 45 min ischemia. There were more abundant autophagozomes and LC3-II expression was significantly increased in SEVO-45 + CAP. Induction of autophagy before ischemia enhanced GSK3 beta phosphorylation and inhibition of calcium-induced MPTP opening. These effects were abolished by 3-methyladenine. Pre-ischemic induction of autophagy restores sevoflurane preconditioning lost by longer ischemic insult. This effect is associated with enhanced inhibition of MPTP by autophagy. (C) 2013 Elsevier B.V. All rights reserved.

In order to investigate the myocardial protective effect of lidocaine, we used a model of myocardial ischemia in anesthetized rabbits to study the effect on infarct size of lidocaine infusion during the first 30 minutes of reperfusion after myocardial ischemia. Japanese white rabbits anesthetized with nitrogen oxide, oxygen and pancuronium were placed on their sides. The left anterior descending coronary artery was exposed via left thoracotomy. Following a 30-minute ischemia to the coronary artery, a 30-minute infusion of lidocaine at 1.0mg/kg/h or physiological saline was started immediately after the initiation of 120-minute reperfusion. During the experiment, systemic blood pressure was continuously monitored using a catheter placed in the femoral artery, and serum lidocaine concentration was determined periodically. At the end of the experiment, the heart was isolated and treated with Evans blue dye to identify the area at risk (AAR) and the non-risk area. The areas of infarction and the risk area were determined using 1% 2,3,5-triphenyltetrazolium chloride (TTC).<br> Although the systemic arterial pressure at 10 and 20 minutes after the coronary ligation was lower than baseline, no significant differences were observed between the lidocaine and saline groups. The AAR and non-risk areas did not differ significantly between the lidocaine and saline groups. The percentage of infarct size per AAR was 14.4% lower in animals receiving lidocaine infusion during reperfusion than in those receiving saline. These findings indicate that high-dose lidocaine infusion protects the myocardium against ischemia-reperfusion injury without affecting blood pressure during reperfusion.

It remains unclear whether p38 mitogen activated protein kinase (p38 MAPK) is involved in anesthetic preconditioning (APC). We investigated the effect of inhibiting p38 MAPK activation on sevoflurane-induced APC. Isolated perfused guinea pig hearts underwent 30 min ischemia and 120 min reperfusion. APC was elicited with 2% sevoflurane administration. Inhibition of p38 MAPK was achieved using SB203580. Contractile recovery was monitored by left ventricular developed (LVDP) and end-diastolic (LVEDP) pressure. Infarct size was determined by triphenyltetrazolium chloride stain. Expression of p38 MAPK was determined by Western blot. After ischemia/reperfusion, APC hearts had higher LVDP and lower LVEDP compared to CTL. Infarct size was significantly reduced in APC. SB203580 administration failed to abolish APC. Western blot analysis demonstrated that phosphorylation of p38 MAPK was increased by APC, which was enhanced by SB 203580.In conclusion, sevoflurane increases p38 MAPK phosphorylation but this is not required for APC.

To assess whether sevoflurane preconditioning is associated with inhibition of mitochondrial permeability transition pore (MPTP), the effects of sevoflurane were compared with those of cyclosporine A, a known inhibitor of MPTP opening. Isolated perfused guinea pig hearts underwent 30 min global ischemia and 120 min reperfusion (control). Sevoflurane preconditioning was elicited by administration of 2% sevoflurane for 10 min with 10 min washout before ischemia (sevoflurane). A preconditioning-like cardioprotection was also induced by administering cyclosporine A (0.2 mu M) for 15 min, starting 5 min before ischemia and for 10 min after the onset of reperfusion (cyclosporine A). Left ventricular developed and end-diastolic pressures, coronary flow and infarct size were measured. Expressions of Akt and glycogen synthase kinase 3 beta (GSK3 beta), known mediators of inhibition of MPTP opening, were determined by Western blot analysis. GSK3 beta inhibition was achieved with LY294002. The effects of sevoflurane and cyclosporine A on calcium-induced MPTP opening in isolated calcein-loaded mitochondria were assessed. After ischemia-reperfusion, sevoflurane and cyclosporine A had higher left ventricular developed pressure. Infarct size was significantly reduced in sevoflurane and cyclosporine A vs. control. This was abolished by LY294002 in sevoflurane, but not in cyclosporine A. Akt and GSK3 beta phosphorylation after reperfusion were significantly increased in sevoflurane and cyclosporine A. Ca2+-induced reduction in calcein fluorescence was significantly attenuated in sevoflurane and cyclosporine A. Preconditioning agents, sevoflurane and cyclosporine A increase the threshold of calcium-induced MPTP opening to a similar extent. This effect by sevoflurane, but not cyclosporine A is at least partially mediated by GSK3 beta inactivation. (C) 2011 Elsevier B.V. All rights reserved.

Volatile anesthetic postconditioning reduces apoptosis through antiapoptotic signaling. Whether sevoflurane postconditioning prevents activation of caspase 9 and 3, which are implicated in the initiation and execution step of apoptosis, is not known. Isolated perfused guinea pig hearts underwent 30 min global ischemia and 120 min reperfusion [control (CTL)]. Anesthetic postconditioning was elicited with sevoflurane (2%) for 2 min at reperfusion onset (POST). LY294002, phosphatidylinositol-3-kinase (PI3K)/Akt (protein kinase B) inhibitor; and PD98059, extracellular signal-regulated kinase 1/2 (ERK) inhibitor, were administered for 10 min before ischemia and throughout the reperfusion period in POST (POST + LY, POST + PD). Left-ventricular-developed (LVDP) and LV end-diastolic (LVEDP) pressures and infarct size were measured. Western blot analysis determined phosphorylated Akt and ERK expression. Myocardial caspase 3 and 9 were determined immunohistochemically. After ischemia-reperfusion, POST had higher LVDP (57 +/- A 9 vs. 38 +/- A 7 mmHg, p &lt; 0.05) and lower LVEDP (21 +/- A 8 vs. 46 +/- A 15 mmHg, p &lt; 0.05) versus CTL. Infarct size was significantly reduced in POST versus CTL (15 +/- A 3 vs. 41 +/- A 11%, p &lt; 0.001). Phosphorylation of Akt and ERK after reperfusion was significantly increased in POST versus CTL. Immunoreactivity for caspase 3 and 9 was greater in the nucleus of myocytes and endothelial cells in CTL. POST attenuated this increased immunoreactivity. LY294002 and PD98059 abolished the effect of POST on caspase 3 and 9 immunoreactivity. Sevoflurane postconditioning prevents activation of caspase 3 and 9, mediators of apoptosis in ischemia-reperfusion injury. This caspase activation is mediated by phosphorylation of Akt and ERK.

BACKGROUND: Volatile anesthetics and regular ethanol consumption induce cardioprotection mimicking ischemic preconditioning. We investigated whether sevoflurane enhances ethanol preconditioning and whether inhibition of protein kinase C (PKC) and mitochondrial K-ATP channels attenuated this enhanced cardioprotection. The effects of regular ethanol consumption on expression of inducible (iNOS) and endothelial (eNOS) nitric oxide synthase were determined. METHODS: Isolated perfused guinea pig hearts underwent 30-min global ischemia and 120-min reperfusion (Control: CTL). The ethanol group (EtOH) received 2.5% ethanol in their drinking water for 6 wk. Anesthetic preconditioning was elicited by 10-min exposure to sevoflurane (I minimum alveolar anesthetic concentration; 2%) in ethanol (EtOH + SEVO) or nonethanol (SEVO) hearts. PKC and mitochondrial K-ATP channels were inhibited with chelerythrine and 5-hydroxydecanoate pretreatment, respectively. Contractile recovery was assessed. by monitoring of left ventricular developed and end-diastolic pressures. Infarct size was determined by triphenyltetrazolium chloride staining. Expression of iNOS and eNOS were determined by Western blot analysis. RESULTS: After ischemia-reperfusion, hearts from the EtOH, sevoflurane (SEVO), and EtOH + SEVO groups had higher left ventricular developed pressure and lower left ventricular end-diastolic pressure compared with CTL. Infarct size was reduced in EtOH and SEVO hearts compared with CTL (27% and 23% vs 45%, respectively, P &lt; 0.001). Sevoflurane further reduced infarct size in EtOH hearts (27% vs 15%, P &lt; 0.001). Chelerythrine and 5-hydroxydecanoate abolished cardioprotection in both SEVO and EtOH cardioprotected hearts. iNOS expression was reduced and eNOS expression was increased in EtOH hearts. CONCLUSIONS: Sevoflurane enhances cardiac preconditioning induced by regular EtOH consumption. This effect is mediated in part by modulation of PKC and mitochondrial K-ATP channels, and possibly by altered modulation of NOS expression.

Volatile anesthetics such as isoflurane and sevoflurane induce cardioprotection mimicking ischemic preconditioning. It has been reported that isoflurane-induced myocardial preconditioning is dependent on phosphatidylinositol-3-kinase (PI 3 K)/Akt signaling which plays a central role in reperfusion injury salvage kinase cascade. It remains unclear whether this signaling cascade is involved in sevoflurane-induced preconditioning. Isolated perfused guinea pig hearts were subjected to 30 min global ischemia and 120 min reperfusion (CTL). Sevoflurane-induced preconditioning was elicited by administration of sevoflurane for 10 min at one minimum alveolar concentration (1 MAC) with 10 min washout before ischemia (SEVO). Contractile recovery was monitored by left ventricular developed pressure (LVDP) and left ventricular end-diastolic pressure (LVEDP). Infarct size (IS) was determined by triphenyltetrazolium chloride (TTC) stain. Phosphorylation of Akt, a downstream target of PI 3 K, was assessed by western blot. After ischemia-reperfusion, SEVO had higher LVDP and lower LVEDP versus CTL. Infarct size was significantly reduced in SEVO compared to CTL (44±8% versus 23±7%). Akt phosphorylation was not increased during ischemia or at 10 min after reperfusion, which is in contrast to the findings previously demonstrated in isoflurane-induced preconditioning. Other reperfusion injury salvage kinases, such as mitogen-activated protein kinase/extra-cellular signal-regulated kinases (MEK) and extra-cellular signal-regulated kinase (ERK), may be more important in sevoflurane-induced preconditioning. (J Osaka Dent Univ 2007 ; 41 : 151-159)

Background. Brain natriuretic peptide (BNP), as a cardiac hormone, is expressed together with atrial natriuretic peptide (ANP) in the ventricles in congestive heart failure. However, the ventricular expression of BNP in hypertrophic cardiomyopathy (HCM) with normal systolic function is still unclear. Methods and Results. The study population consisted of 39 HCM patients with asymmetric septal hypertrophy and 10 control subjects without any specific cardiac disease. Eleven cases of HCM were obstructive (HOCM), and the other 28 cases were nonobstructive (HNCM). All of these patients had a normal ejection fraction. Immunohistochemical analysis of endomyocardial biopsy specimens with specific monoclonal antibodies showed BNP immunoreactivity in the HOCM group (5/10,50%) but not in the HNCM group (0/22) or in control subjects (0/5). In HOCM, left ventricular end-diastolic pressure was significantly higher in the BNP-positive patients than the BNP-negative patients. Histological changes such as myocardial fiber disarray, hypertrophy of myocytes, and fibrosis were greater in BNP-positive patients than BNP-negative patients in HCM. However, the expression had no significant relation with other clinical parameters. The elevation of the BNP plasma level versus control subjects was marked in both HOCM (85-fold) and HNCM (23-fold). By contrast, the elevation of the ANP plasma level versus control subjects was mild in HOCM (5.7-fold) and HNCM (4.2-fold). The ratio of BNP level to ANP level was higher in HOCM (4.16) than in HNCM (1.46) and control subjects (0.28), and it was higher than the ratio previously reported for severe congestive heart failure (1.72). Conclusions. These findings suggest that BNP is expressed in the ventricular myocytes of HCM with normal systolic function. In HOCM, ventricular expression of BNP may be augmented in response to both obstruction and diastolic dysfunction.

Background. It has been reported that a brief period of coronary occlusion and reperfusion slows the rate of ATP depletion during subsequent sustained ischemia as well as limiting infarct size. However, it has not yet been determined whether ischemic preconditioning also has an effect on the functional and metabolic recovery of stunned myocardium. Our study was designed to address this problem. Methods and Results. Farm pigs were anesthetized with fluothane and randomly assigned to either a control group or a preconditioned group. The control group (n=15) underwent 15 minutes of coronary occlusion followed by 120 minutes of reperfusion. The preconditioned group (n=14) underwent two episodes of 5-minute occlusion and 5-minute reperfusion followed by 15 minutes of occlusion and 120 minutes of reperfusion. This protocol was designed to exclude the stunning effect of the preconditioning procedure itself as much as possible besides preconditioning the heart. A pair of ultrasonic crystals was implanted in the area at risk perfused by the left anterior descending coronary artery. P-31-nuclear magnetic resonance spectroscopy and sonomicrometry were performed alternately. Regional myocardial blood flow (RMBF) was determined with colored microspheres. At 15 minutes of sustained ischemia, phosphocreatine (Pcr), ATP, and intracellular pH were significantly better preserved in the preconditioned group (Pcr: control/preconditioned, 1+/-1%/14+/-1%; ATP:control/preconditioned, 66+/-2%/74+/-2%; pH:control/preconditioned, 6.32+/-0.07/6.52+/-0.05; P&lt;.05). After reperfusion, ATP increased progressively and was almost normalized at 120 minutes of reperfusion in the preconditioned group (control/preconditioned, 73+/-4%/95+/-3%; P&lt;.05). Overshoot of Pcr (which indicates that the energy generating system is operating better than energy utilizing system) persisted in preconditioned hearts but disappeared rapidly in controls (control/preconditioned, 104+/-3%/130+/-3% after 120 minutes of reperfusion). There was no significant difference in percent segment shortening (%SS), RMBF, and hemodynamics between the two groups throughout the experiment (%SS: control/preconditioned, 29.8+/-5.9%/28. 8+/-6.3% of baseline after 120 minutes of reperfusion). Conclusions. Preconditioning improves energy metabolism during reperfusion, although it does not attenuate myocardial stunning for at least 2 hours after reperfusion. (Circulation 1993;88:223-234)

Objectives. The purpose of this study was to examine the histologic-angiographic correlates of chronic total coronary occlusion and to explain why a tapering type of occlusion and short occluded segments are favorable for percutaneous transluminal coronary angioplasty. Background. Coronary angioplasty is less successful for vessels with chronic total occlusion than for highly stenotic but patent vessels. Several clinical and angiographic factors determining the rate of initial success have been investigated, but the underlying histologic features are not clear. Methods. Ten autopsy hearts that showed chronic total coronary occlusion on cineangiography performed less-than-or-equal-to 3 months before death were selected. In all, the estimated duration of occlusion was &gt;1 year. At autopsy, postmortem angiography was performed and hearts were fixed with 10% buffered formalin. Occluded segments were sectioned transversely and serially into slices 10 mum thick. Every five slices were stained in hematoxylin-eosin and elastic van-Gieson. Results. Ten hearts with chronic total coronary occlusion were angiographically classified into five with a tapering and five with an abrupt type of occlusion and seven with a short (less-than-or-equal-to 15 mm) and three with a long (&gt; 15 mm) occluded segment. Histologically, the occluded segment was composed of loose or dense fibrous tissue, atheroma, small vascular channels and calcified tissue. Reconstruction of the serial preparations showed that small lumen recanalized areas (diameter 160 to 230 mum) with surrounding loose fibrous tissue penetrated the occluded segment in four hearts with occlusion of the tapering type and a short occluded segment. In these four cases, the lack of anterograde flow on cineangiography could be explained by the presence of rich collateral flow. In three cases of the abrupt type of occlusion with a short occluded segment, a mass of loose fibrous tissue penetrated the occluded segment. In hearts with a long occluded segment (one with a tapering type of occlusion and two with an abrupt type), there was no recanalization and loose fibrous tissue was dispersed in the occluded segment. Conclusions. Chronic total coronary occlusion of the tapering type or with a short occluded segment, or both, is possibly favorable for angioplasty, because small lumen recanalized areas or loose fibrous tissue penetrates the occluded segment and may form a route for successful angioplasty.

Zotepine(2-chloro-11-(2-diethyl-aminoethoxy)dibenzo[b.f.]thiepin)has been reported to decrease serum uric acid levels in schizophrenics. We have investigated its uricosuric effect by uric acid clearance, inosine loading test, and PZA suppression test.<BR>Oral administration of 20 mg of zotepine to 3 normal volunteers resulted in moderate uricosuria in 2 or 3 hours, which paralleled the increase of the serum concentration of the drug. In 20 gouty subjects, after administration of zotepine 20mg/day for 14 days, uric acid clearance revealed a decrease of uric acid (1.5±1.8mg/dl). Inosine loading test showed increases of SUA, UUA and CUA. These changes were similar to those of benzbromarone (potent uricosuric agent), but different from those of allopurinol (uric acid production inhibitor), and suggested that zotepine is an uricosuric agent.<BR>In a normal volunteer, who was given 4g of PZA previously, zotepine- induced uricosuria disappeared. PZA is a potent tubular secretion inhibitor. Therefore, zotepine may inhibit tubular secretion, or postsecretory tubular reabsorption.