Combination of necroptosis and apoptosis inhibition enhances cardioprotection against myocardial ischemia-reperfusion injury.

PURPOSE: Necroptosis has been proposed as a mode of cell death that is a caspase-independent programmed necrosis. We investigated whether necroptosis is involved in myocardial ischemia-reperfusion injury in isolated guinea pig hearts and, if so, whether simultaneous inhibition of necroptosis and apoptosis confers enhanced cardioprotection. METHODS: Isolated perfused guinea pig hearts were subjected to 30 min ischemia and 4 h reperfusion (control = CTL, n = 8). Necrostatin-1 (necroptosis inhibitor, 10 µM), Z-VAD (apoptosis inhibitor, 0.1 µM) and both inhibitors were administered starting 5 min before ischemia and during the initial 30 min of reperfusion (Nec, Z-VAD, Nec + Z-VAD; n = 8 each). Contractile recovery was monitored by left ventricular developed (LVDP) and end-diastolic (LVEDP) pressure. Infarct size was determined by triphenyltetrazolium chloride staining. Tissue samples were obtained after 4 h reperfusion to determine expression of receptor-interacting protein 1 (RIP1) and activated caspase 3 by Western blot analysis. RESULTS: After reperfusion, Nec + Z-VAD had higher LVDP and lower LVEDP compared with CTL. Infarct size was reduced in Nec and Z-VAD compared with CTL. Combination of necroptosis and apoptosis inhibition further reduced infarct size. Expression of activated caspase 3 was not increased in Z-VAD and Nec + Z-VAD compared with Nec and CTL. Expression of RIP1 was preserved in Z-VAD and Nec + Z-VAD compared with CTL, suggesting RIP1-mediated necrosis is involved in myocardial ischemia-reperfusion injury. CONCLUSION: Necroptosis is involved in myocardial ischemia-reperfusion injury, and simultaneous inhibition of necroptosis and apoptosis enhances the cardioprotective effect. These findings may provide a novel, additive strategy for cardioprotection in acute myocardial infarction.

Sevoflurane induces cardioprotection through reactive oxygen species-mediated upregulation of autophagy in isolated guinea pig hearts.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: Sevoflurane induces cardioprotection through ROS-mediated upregulation of autophagy.

Sevoflurane confers additive cardioprotection to ethanol preconditioning associated with enhanced phosphorylation of glycogen synthase kinase-3ß and inhibition of mitochondrial permeability transition pore opening.

OBJECTIVE: The purposes of this study were to investigate whether sevoflurane (SEVO) enhances moderate-dose ethanol (EtOH) preconditioning and whether this additional cardioprotection is associated with glycogen synthase kinase-3ß (GSK-3ß), protein kinase B (Akt), mammalian target of rapamycin (mTOR), 70-kDa ribosomal s6 kinase-1 (p70s6K), and/or mitochondrial permeability transition pore (MPTP) opening. DESIGN: In vitro study using an isolated heart Langendorff preparation. SETTING: University research laboratory. PARTICIPANTS: Male guinea pigs (n = 170). INTERVENTIONS: Isolated perfused guinea pig hearts underwent 30-minute ischemia and 120-minute reperfusion (control). The EtOH group received 5% EtOH in the drinking water for 8 weeks. Anesthetic preconditioning was elicited by a 10-minute exposure to 2% SEVO in EtOH (EtOH + SEVO group) or non-EtOH (SEVO group) hearts. The inhibition of GSK-3ß phosphorylation and mTOR was achieved with LY294002 and rapamycin, respectively. GSK-3ß, Akt, mTOR, and p70s6K expressions were determined by western blot. Calcium-induced MPTP opening was assessed in isolated calcein-loaded mitochondria. MEASUREMENTS AND MAIN RESULTS: After ischemia-reperfusion, the EtOH, SEVO, and EtOH + SEVO groups had higher left ventricular developed pressure recovery and lower end-diastolic pressure versus the control group. Infarct size was smaller in the EtOH and SEVO groups versus control and even smaller in the EtOH + SEVO group. Phosphorylation of GSK-3ß and Akt, but not mTOR and p70s6K, was increased in the EtOH and SEVO groups. Phosphorylation of GSK-3ß, but not mTOR and p70s6K, was further increased in the EtOH + SEVO group. The EtOH and SEVO groups exhibited a smaller calcium-induced MPTP opening, and the EtOH + SEVO presented an even smaller MPTP opening. CONCLUSIONS: SEVO and chronic EtOH preconditioning offer additive cardioprotection. This effect is associated with an increased GSK-3ß phosphorylation and an inhibition of MPTP opening.

Changes in blood pressure during induction of anesthesia and oral and maxillofacial surgery by type and timing of discontinuation of antihypertensive drugs.

The purpose of this study was to evaluate the effects of an antihypertensive drug class and the timing of discontinuation of antihypertensive therapy on blood pressure during oral and maxillofacial surgery for 129 patients on antihypertensive therapy receiving general anesthesia. Blood pressures at loss of response to stimulation and 5-15 minutes after intubation were significantly lower than those before induction, although the type of antihypertensive therapy did not affect changes in blood pressure. No significant correlation was observed between systolic blood pressure (SBP) on the ward and change in SBP during surgery, though patients with higher blood pressure on the ward tended to exhibit larger differences between SBP on the ward and the lowest SBP during surgery. Frequency of use of vasopressors during surgery was significantly higher in patients who discontinued antihypertensive therapy on the day before surgery than in those who continued antihypertensive therapy on the day of surgery. These findings suggest that appropriate preoperative antihypertensive therapy is important for minimizing change in blood pressure during surgery and preventing perioperative complications. Patients undergoing antihypertensive therapy should be carefully monitored perioperatively by observation for interactions between antihypertensive and anesthetic agents and minimizing interruption schedules for antihypertensive therapy.

Anesthetic Management of a Patient With Restless Legs Syndrome: A Case Report.

Restless legs syndrome (RLS) is a neurological sensory disorder associated with sensory and motor symptoms that most commonly occur at night and during periods of rest. It is characterized by altered or abnormal sensations primarily in the legs and the urge to move the associated limbs. Perioperative procedures, including general anesthesia, can cause exacerbations of RLS. This is a case report of a suspected RLS exacerbation in a 22-year-old woman who had no formal diagnosis of RLS despite reporting symptoms that met all essential diagnostic criteria by the International RLS Study Group. Despite her previous diagnoses of dehydration induced-muscle pain or nocturnal cramps, we suspected her to have RLS. The patient underwent general anesthesia for a bilateral sagittal split ramus osteotomy using a combined inhalational and intravenous anesthetic technique with sevoflurane, propofol, remifentanil, and dexmedetomidine. After successful completion of the surgery and returning to the ward, she began moving her lower extremities and complaining of unpleasant sensations in both ankles. Bed rest exacerbated the suspected RLS symptoms despite a continuous infusion of dexmedetomidine. The RLS symptoms continued to worsen and spread to her upper extremities. After increasing the dexmedetomidine infusion from 0.2 to 0.4 µg/kg/h, almost all symptoms improved, and she slept for 3 hours. Upon awakening, the unpleasant sensations were completely relieved by walking and stretching. The patient was formally diagnosed with RLS by a neurologist after discharge. In this case, an infusion of dexmedetomidine was helpful in successfully managing a suspected exacerbation of RLS.

Aprotinin abolishes sevoflurane postconditioning by inhibiting nitric oxide production and phosphorylation of protein kinase C-delta and glycogen synthase kinase 3beta.

BACKGROUND: It remains controversial whether aprotinin use during cardiac surgery is cardioprotective or detrimental. In contrast, volatile anesthetics may offer cardioprotection perioperatively. Increased nitric oxide, protein kinase C activation, and glycogen synthase kinase 3beta inhibition play a role in sevoflurane-induced cardioprotection. The authors investigated whether aprotinin affects sevoflurane postconditioning. METHODS: Isolated guinea pig hearts underwent 30 min of global ischemia and 120 min of reperfusion (control [CTL]). Postconditioning was elicited with sevoflurane (2%) for 2 min at reperfusion onset (POST). Aprotinin (250 kallikrein inhibitor units/ml) was administered for 5 min at reperfusion onset (POST + APRO and CTL + APRO). In additional experiments, both sevoflurane and aprotinin were given before ischemia and throughout the reperfusion period (SEVO + APRO (throughout)) to mimic clinical conditions. Left ventricular developed and end-diastolic pressures and infarct size were measured. Western blot analysis determined phosphorylated protein kinase C-delta, protein kinase C-delta, Akt, and glycogen synthase kinase 3beta expression. Nitric oxide production during reperfusion was measured by nitric oxide sensor. RESULTS: After ischemia-reperfusion, POST had significantly higher left ventricular developed (56 +/- 11 vs. 26 +/- 8 mmHg [mean +/- SD]) and lower end-diastolic pressures (20 +/- 9 vs. 47 +/- 15 mmHg) and reduced infarct size (15 +/- 3% vs. 41 +/- 10%) versus CTL. Aprotinin abolished these improvements. Expressions of phospho-Akt (activated), phospho-protein kinase C-delta (activated), and phospho-glycogen synthase kinase 3beta (inhibited) were significantly increased in POST. Aprotinin attenuated these increased expressions. Nitric oxide production after reperfusion was higher in POST than in CTL, but not in POST + APRO. CONCLUSIONS: Aprotinin abolishes sevoflurane postconditioning, associated with inhibited phosphorylation of Akt, protein kinase C-delta, and glycogen synthase kinase 3beta and reduced nitric oxide production.

Acute memory phase of sevoflurane preconditioning is associated with sustained translocation of protein kinase C-alpha and epsilon, but not delta, in isolated guinea pig hearts.

BACKGROUND AND OBJECTIVE: Anaesthetic preconditioning (APC) exerts cardioprotective effects by reducing infarct size and improving recovery of contractile function after ischaemia-reperfusion. The interval between brief exposure to volatile anaesthetic and sustained ischaemia, the acute memory phase, is dependent on intracellular signalling mediating this cardioprotection. Intramyocyte translocation of protein kinase C (PKC) is known to be a key mediator in APC. We examined the relationship between the time frame of the acute memory phase of sevoflurane preconditioning and intramyocyte translocation of PKC-alpha, delta and epsilon to the particulate fraction. METHODS: Isolated perfused guinea pig hearts were subjected to 30 min ischaemia and 120 min reperfusion. APC was elicited with one minimum alveolar concentration sevoflurane for 10 min. Washout times of 10, 30, 60 and 90 min were studied. Contractile recovery was assessed by monitoring left ventricular developed pressures. Infarct size was determined by triphenyltetrazolium chloride staining. Translocation of PKC was examined by western blot analysis. RESULTS: After ischaemia-reperfusion, left ventricular developed pressure recovered to a greater degree with APC compared with control for washout times of 10 and 30 min, but not 60 and 90 min. Similarly, infarct size was reduced for washout times of 10 and 30 min, but not 60 and 90 min. Sustained translocation of PKC-alpha and epsilon, but not delta, was associated with the time frame of the acute memory phase. CONCLUSION: The acute memory phase of sevoflurane preconditioning is limited to less than 60 min. Sustained translocation of PKC-alpha and epsilon, but not delta, correlates with this acute memory phase of sevoflurane preconditioning.

Sevoflurane enhances ethanol-induced cardiac preconditioning through modulation of protein kinase C, mitochondrial KATP channels, and nitric oxide synthase, in guinea pig hearts.

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 (1 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 < 0.001). Sevoflurane further reduced infarct size in EtOH hearts (27% vs 15%, P < 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.

Electrochemical treatment of human urine for its storage and reuse as flush water.

We proposed the electrochemical treatment of human urine to enable its storage without the accompanying unpleasant odor. This urine can then be reused as flush water in toilets as a means to tackle water shortage problems. In laboratory-scale experiments, the time-dependent variation in the pH of human urine, after the addition of urease, could be suppressed by chlorine produced via the electrochemical treatment of diluted human urine. Ureolysis was quantified by pH increase within 100 h. This suppression occurred as a result of an irreversible change in the conformation of urease that resulted in its inactivation at an oxidation-reduction potential (ORP) of ca. 240 mV or above. Due to the electrochemical inactivation of urease during the entire storage period of urine, the hydrolysis of urea in urine, which results in the production of the unpleasant odor due to ammonia formation, can be avoided. Thus, the treatment enables the storage of urine for its reuse as flush water in toilets.

[A case of anesthesia for a patient with a huge pheochromocytoma accompanying difficulty in hemodynamics control].

A 33-year-old man with diabetes mellitus developed a left pheochromocytoma, 9 cm diameters in size, of adrenalin predominance type. He underwent laparoscopic adrenalectomy. Anesthesia was induced with propofol and vecuronium, and maintained with continuous infusion of propofol. Lopivacaine was also used for epidural anesthesia. From the beginning of the operation, blood pressure was well controlled using prostaglandin E1 and landiolol continuously. However, the bleeding from the adrenal vein occurred in the middle of the operation. This incidence obliged us to alter the operation from laparoscopic to open surgery. It turned difficult to control blood pressure although antihypertensive drugs, such as prostaglandin E1, phentolamine and landiolol, were used. However, it was difficult to suppress unexpected high blood pressure and tachycardia with alteration of the operative procedure.

Regular dipyridamole therapy produces sustained protection against cardiac ischemia-reperfusion injury: is it time to revisit PARIS?

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.

Induction of autophagy restores the loss of sevoflurane cardiac preconditioning seen with prolonged ischemic insult.

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 min 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 µM) was administered starting 20 min before ischemia and throughout reperfusion in SEVO-45 (SEVO-45+CAP). To inhibit autophagy, 3-methyladenine (10 µM) was administered during sevoflurane administration in SEVO-45+CAP. 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), Akt and glycogen synthase kinase 3ß (GSK3ß) 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 GSK3ß 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.

Direct evidence for inhibition of mitochondrial permeability transition pore opening by sevoflurane preconditioning in cardiomyocytes: comparison with cyclosporine A.

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 µM) 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 3ß (GSK3ß), known mediators of inhibition of MPTP opening, were determined by Western blot analysis. GSK3ß 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 GSK3ß phosphorylation after reperfusion were significantly increased in sevoflurane and cyclosporine A. Ca²âº-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 GSK3ß inactivation.

Cardioprotection by regular ethanol consumption: potential mechanisms and clinical application.

Epidemiological studies demonstrate that excessive drinking is associated with hypertension, cerebral bleeding and loss of cardiac contractility. Conversely, studies have shown that mortality rates for people who regularly drink ethanol in moderation are lower than in abstainers, primarily due to decreased fatal ischemic heart disease. Further, moderate ethanol consumers have lower rates of myocardial infarction compared with abstainers. These beneficial cardiac effects may be due to pleiotropic effects of ethanol on lipids, platelets, and fibrinolytic activity. During the past decade, studies conducted in several animal models have revealed that light to moderate regular ethanol consumption renders hearts more tolerant to myocardial ischemia-reperfusion injury; to a degree similar to cardiac ischemic preconditioning (brief episodes of ischemia dramatically limit infarct size following prolonged ischemia). Recent clinical evidence suggests that light to moderate ethanol consumption in the year prior to myocardial infarction is associated with reduced mortality following myocardial infarction. These findings suggest that light to moderate ethanol consumption not only prevents myocardial infarction but also improves survival after myocardial infarction. Proposed mechanisms of cardioprotection by regular ethanol consumption include activation of adenosine A1 receptors, alpha(1)-adrenoceptors, protein kinase C-delta and epsilon, adenosine triphosphate-dependent potassium (K(ATP)) channels, nitric oxide synthase and reduced leukocyte-endothelial cell adhesive interactions. In this review, we focus on the recent progress in elucidating the endogenous myocyte signaling mediating cardioprotection by light to moderate ethanol consumption.