Myocardial protection by anesthetic agents against ischemia-reperfusion injury: an update for anesthesiologists

Remote ischemic preconditioning reduces cardiac troponin I release in cardiac surgery: a meta-analysis

OBJECTIVES

To determine whether remote ischemic preconditioning (RIPC) reduces myocardial injury, mortality, morbidity, and resource utilization in cardiac surgery.

DESIGN

Meta-analysis of controlled clinical trials. The primary outcome was cardiac troponin I (cTnI) concentrations. Secondary outcomes included cardiac troponin T (cTnT) concentrations, myocardial infarction, stroke, renal failure requiring hemodialysis, atrial fibrillation, inotropic score, mechanical ventilation time, length of intensive care unit stay, length of hospital stay, and death.

SETTING

University hospitals.

PATIENTS

Adult and pediatric patients undergoing cardiac surgery, including coronary artery bypass grafting, valve procedures, and correction of congenital cardiac anomalies.

INTERVENTIONS

Remote ischemic preconditioning through limb ischemia.

MEASUREMENTS AND MAIN RESULTS

Nineteen randomized trials involving 1,235 patients were included in the meta-analysis. The cTnI concentrations at 6 (or 4-8) hours postoperatively and the total cTnI released after surgery showed a statistically significant reduction in the RIPC group compared with a control group (weighted mean difference [WMD] -2.03 ug/L, 95% confidence interval [CI] -3.25 to -0.82 ug/L, p = 0.001; WMD -65.74 ug/L*h, 95% CI -107.88 to -23.61 ug/L*h, p = 0.002, respectively). There were no differences in mortality, morbidity, and resource utilization between groups.

CONCLUSIONS

Current evidence suggests that RIPC reduces cardiac troponin I release in patients undergoing cardiac surgery. The clinical significance of these observations merits further investigation.

Propofol induces DNA damage in mouse leukemic monocyte macrophage RAW264.7 cells

Propofol is one of the most widely clinically used intravenous anesthetic, and it induces apoptosis in human and murine leukemia cell lines. Yet, whether propofol causes DNA damage and affects the mRNA expression of repair-associated genes in cancer cells remains undetermined. In the present study, we investigated the effects of propofol on DNA damage and associated mRNA gene expression in RAW264.7 cells. Comet assay and DNA gel electrophoresis were used to evaluate DNA damage in RAW264.7 cells and propofol-inhibited cell growth in vitro. The results revealed a longer DNA tail and DNA fragmentation. Real-time PCR assay was used to examine mRNA gene expression of DNA damage and DNA repair-associated genes. Following exposure to propofol for 48 h, a decrease in the mRNA expression of DNA-PK, BRCA1, MGMT and p53 was noted in the RAW264.7 cells. Results from the western blotting indicated that p53, MGMT, 14-3-3-σ, BRCA1 and MDC1 proteins were decreased while p-p53 and p-H2A.X(S140) were increased in the RAW264.7 cells following exposure to propofol. In conclusion, exposure to propofol caused DNA damage and inhibited mRNA expression and protein levels of repair-associated genes in RAW264.7 cells.

cDNA microarray analysis of the gene expression of murine leukemia RAW 264.7 cells after exposure to propofol

Propofol (2,6-diisopropylphenol) is the most extensively used general anesthetic-sedative agent and it is employed in clinical patients. It has been shown that propofol exhibits anticancer activities. However, there is no available information to address propofol-induced cytotoxic effects and affected gene expressions on murine leukemia cells. Therefore, we investigated the effects of propofol on the levels of protein and gene expression, which are associated with apoptotic death in mouse leukemia RAW 264.7 cells in vitro. Results indicated that propofol induced cell morphological changes, cytotoxicity, and induction of apoptosis in RAW 264.7 cells in vitro. Western blot analysis demonstrated that propofol promoted Fas, cytochrome c, caspase-9 and -3 active form and Bax levels, but inhibited Bcl-xl protein level which led to cell apoptosis. Furthermore, cDNA microarray assay indicated that propofol significantly enhanced 5 gene expressions (Gm4884; Gm10883; Lce1c; Lrg1; and LOC100045878) and significantly suppressed 26 gene expressions (Gm10679; Zfp617; LOC621831; LOC621831; Gm5929; Snord116; Gm3994; LOC380994; Gm5592; LOC380994; Gm4638; LOC280487; Gm4638; Tex24; A530064D06Rik; BC094916; EG668725; Gm189; Hist2h3c2; Gm8020; Snord115; Gm3079; Olfr198; Tdh; Snord115; and Olfr1249). Based on these observations, propofol-altered apoptosis-related proteins might result from induction of apoptotic gene expression and inhibition of cell growth gene expression, which finally led to apoptosis in a mouse leukemia cell line (RAW 264.7) in vitro.

Effect of modulating the allosteric sites of N-methyl-D-aspartate receptors in ischemia-reperfusion induced acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is one of the major health problems in developed as well as developing countries. The literature regarding the role of N-methyl-D-aspartate receptors (NMDAR) and the impact of the modulation of its allosteric sites on renal function is inadequate. The present study investigated the effect of modulating allosteric sites of NMDAR in ischemia-reperfusion-induced AKI.

MATERIALS AND METHODS

We subjected rats to bilateral renal ischemia for 40 min followed by reperfusion for 24 h to induce AKI. We measured blood urea nitrogen, serum creatinine, uric acid, and lactate dehydrogenase to assess kidney injury. We assayed the thiobarbituric acid-reactive substances, reduced glutathione level, and myeloperoxidase and catalase activity to assess oxidative stress in renal tissue, and used hematoxylin-eosin staining to observe histopathologic changes.

RESULTS

Ischemia-reperfusion induced AKI, as demonstrated by an increase in serum parameters, oxidative stress and histopathologic changes in renal tissue. The NMDA agonist glutamic acid and polyamine binding site agonist spermidine significantly aggravated oxidative stress and ischemia-reperfusion-induced AKI. Various NMDA receptor antagonists, including glycine binding site inhibitor kynurenic acid, polyamine binding site inhibitor ketamine, and channel blocking agent magnesium sulfate, attenuated ischemia-reperfusion-induced AKI and significantly reduced oxidative stress, which suggests a role for NMDA receptors and the importance of regulating its allosteric sites in AKI.

CONCLUSIONS

Acute kidney injury is associated with the activation of NMDA receptors, as well as significant oxidative stress. The antagonism of various allosteric sites of NMDA receptors affords significant benefit against ischemia-reperfusion-induced AKI.

Antioxidant effects of methylprednisolone and hydrocortisone on the impairment of endothelium dependent relaxation induced by reactive oxygen species in rabbit abdominal aorta

Background

The reperfusion following ischemia produces reactive oxygen species (ROS). We studied the influences of methylprednisolone (MPD) and hydrocortisone (CRT) on ROS effects using the endothelium of rabbit abdominal aorta.

Methods

Isolated rabbit aortic rings were suspended in an organ bath filled with Krebs-Henseleit (K-H) solution. After precontraction with norepinephrine, changes in arterial tension were recorded following the cumulative administration of acetylcholine (ACh). The percentages of ACh-induced relaxation of aortic rings before and after exposure to ROS, generated by electrolysis of K-H solution, were used as the control and experimental values, respectively. The aortic rings were pretreated with MPD or CRT at the same concentrations, and the effects of these agents were compared with the effects of ROS scavenger inhibitors: superoxide dismutase inhibitor, diethylthiocarbamate (DETCA), and the catalase inhibitor, 3-amino-1,2,4-triazole (3AT).

Results

Both MPD and CRT maintained endothelium-dependent relaxation induced by ACh in a dose-related manner in spite of ROS attack. The restored ACh-induced relaxation of MPD and CRT group was not attenuated by pretreatment of 3AT and DETCA.

Conclusions

MPD and CRT preserve the endothelium-dependent vasorelaxation against the attack of ROS, in a dose-related manner. Endothelial protection mechanisms of MPD and CRT may be not associated with hydrogen peroxide and superoxide scavenging.

Assessment of oxidative stress and antioxidant property using electron spin resonance (ESR) spectroscopy

The pathophysiology of hypertension or stroke is associated with an excess of ROS generation in the vascular system, and results in induction of various pathological cascades of cerebrovascular damage. We have demonstrated that electron spin resonance methods using a spin trap or spin probe will be useful for understanding redox status under conditions of oxidative stress in the spontaneously hypertensive rat or stroke-prone spontaneously hypertensive rat brain. We have used electron spin resonance imaging and noninvasive L-band electron spin resonance to characterize the higher degree of brain oxidative stress in the stroke-prone spontaneously hypertensive rat and spontaneously hypertensive rat than in the Wistar-Kyoto rat brain, and the lower extent of oxidative stress in the spontaneously hypertensive rat than in the stroke-prone spontaneously hypertensive rat brain. Indeed, we may be able to confirm propofol medium-chain triglyceride/long-chain triglyceride (MCT/LCT) as neuroprotective anesthesia and crocetin as antioxidant food factor against human stroke after screening for antioxidant properties in stroke models such as stroke-prone spontaneously hypertensive rat. Thus, our electron spin resonance biomedical application suggests that it could be used to assess antioxidant effects on oxidative stress in the brain using spontaneously hypertensive rat and stroke-prone spontaneously hypertensive rat. We hope that further advances in the instrumentation used for electron spin resonance imaging and the development of optimized nontoxic spin probes will make this technology even more promising for novel clinical prediction or noninvasive diagnosis of human stroke. After screening drugs or foods for antioxidant property using in vitro or in vivo electron spin resonance assessment, it will be possible to find and develop novel drugs or food factors with such properties for the prevention of stroke in the near future.

Effect of propofol on oxidative stress status in erythrocytes from dogs under general anaesthesia

Background

Alterations of the normal redox balance might be attributed to increase of plasma free-radical concentration and a disruption of the antioxidant defense system. One of the adverse effects of general anaesthetics is the exogen sources of reactive oxygen radicals that are responsible for several diseases. The purposes of the current study were to evaluate the effect of propofol on oxidative stress and to compare the differences between propofol induction only and induction plus continuous infusion on antioxidant status in dogs.

Findings

Beagle dogs were evaluated in the present study. The dogs were assigned randomly to receive three treatments in a crossover model. The three treatments were: group 1 (n = 9), 2% isoflurane; group 2 (n = 9), anaesthesia induced with an intravenous (IV) bolus dose of 6 mg/kg propofol and maintained with 1.5–2% isoflurane; group 3 (n = 9), total IV anaesthesia (induction with 6 mg/kg propofol, infusion with 0.6 mg/kg/min propofol). The results of this study show that dogs exposed to isoflurane had decreased antioxidant enzymes activities, whereas dogs injected with propofol had increased antioxidant enzymes activities.

Conclusions

The results of this study showed that an infusion dose of propofol has antioxidant effects in dogs. These effects may be beneficial to patients in whom free radicals play a role in oxidative stress, such as those with ischemia. Further studies are needed to evaluate whether these antioxidant effects of the anaesthetic are of clinical value.

Dexmedetomidine did not reduce the effects of tourniquet-induced ischemia-reperfusion injury during general anesthesia

Ischemia reperfusion injury causes the release of free oxygen radicals. Free oxygen radicals initiate the production of toxic metabolites, such as malondialdehyde (MDA), through the lipid peroxidation of cellular membranes. Following lipid peroxidation, the antioxidant enzyme system is activated against reactive oxygen species (ROS) and attempts to protect cells from oxidative damage. There is a balance between the scavenging capacity of antioxidant enzymes and ROS. Because of this balance, the total antioxidant capacity (TAC) measurement is a sensitive indicator of the overall protective effects of the antioxidants. Alpha(2) receptor agonists are effective in preventing hemodynamic reactions during extremity surgeries by preventing the release of catecholamines secondary to tourniquet application. They have also been shown to possess preventive effects in various ischemia-reperfusion injury models. In our study, we examined the effects of dexmedetomidine on tourniquet-induced ischemia-reperfusion injury in lower extremity surgeries performed under general anesthesia. The effects of dexmedetomidine were measured with serum MDA and TAC levels. We studied 60 adult American Society of Anesthesiologists (ASA) physical status I or II patients undergoing one-sided lower extremity surgery with tourniquet. The patients were randomly divided into two groups. Group D was administered a dexmedetomidine infusion at a rate of 0.1μg/kg/minute(-1) for 10 minutes prior to induction and then at 0.7μg/kg/hour(-1) until 10 minutes before the end of the operation. The control group (Group C) received a saline infusion of the same amount and for the same period of time. General anesthesia was induced with thiopental, fentanyl, and rocuronium and maintained with nitrous oxide and sevoflurane in both groups. Venous blood samples were obtained before the administration of the study drugs (basal) at 1 minute before tourniquet release and at 5 and 20 minutes after tourniquet release (ATR). In both groups, MDA levels decreased at 5 and 20 minutes ATR when compared with the basal values (p<0.05). TAC levels decreased at 1 and 5 minutes ATR and then returned to basal values at 20 minutes ATR (p<0.05). In reference to the prevention of lipid peroxidation in tourniquet-induced ischemia-reperfusion injury, the results from the two groups in our study showed that dexmedetomidine did not have an additional protective role during routine general anesthesia.

Breath pentane as a potential biomarker for survival in hepatic ischemia and reperfusion injury--a pilot study

Background

Exhaled pentane, which is produced as a consequence of reactive oxygen species-mediated lipid peroxidation, is a marker of oxidative stress. Propofol is widely used as a hypnotic agent in intensive care units and the operating room. Moreover, this agent has been reported to inhibit lipid peroxidation by directly scavenging reactive oxygen species. In this study, using a porcine liver ischemia-reperfusion injury model, we have evaluated the hypothesis that high concentrations of breath pentane are related to adverse outcome and that propofol could reduce breath pentane and improve liver injury and outcome in swine in this situation.

Methodology/Principal Findings

Twenty male swine were assigned to two groups: propofol (n = 10) and chloral hydrate groups (n = 10). Hepatic ischemia was induced by occluding the portal inflow vessels. Ischemia lasted for 30 min, followed by reperfusion for 360 min. Exhaled and blood pentane concentrations in the chloral hydrate group markedly increased 1 min after reperfusion and then decreased to baseline. Breath and blood pentane concentrations in the propofol group increased 1 min after reperfusion but were significantly lower than in the chloral hydrate group. A negative correlation was found between breath pentane levels and survival in the chloral hydrate group. The median overall survival was 251 min after reperfusion (range 150–360 min) in the chloral hydrate group. All of the swine were alive in the propofol group.

Conclusions

Monitoring of exhaled pentane may be useful for evaluating the severity of hepatic ischemia-reperfusion injury and aid in predicting the outcome; propofol may improve the outcome in this situation.

Neuroprotective effects of racemic ketamine and (S)-ketamine on spinal cord injury in rat

BACKGROUND

The aim of this study was to investigate and to compare the potential neuroprotective effects of racemic ketamine, (S)-ketamine and methylprednisolone after an experimental spinal cord injury model in rats.

METHODS

Fifty-nine Wistar albino rats were divided into three main groups as acute stage (A), subacute stage (SA) and sham groups and then acute and subacute stage groups were divided into four groups regarding the used drug as control (CONT), racemic ketamine (RK), (S)-ketamine (SK) and methylprednisolone (MP) groups. A dorsal laminectomy was performed; and spinal cord injury was induced by using a temporary aneurysm clip. Four hours later from the clip compression, except those of the sham and control groups, the drugs (60 mg/kg racemic ketamine, 60 mg/kg (S)-ketamine or 30 mg/kg methylprednisolone) were administered intraperitoneally. At 72th h and 7th days of the study, the spinal cords of rats were removed from T8 level to the conus medullaris level. The specimens were and evaluated histopathologically, tissue lipid peroxidation (LPO) and myeloperoxidation (MPO) levels were measured and biochemically.

RESULTS

The histopathological results were similar both in the acute and in the subacute stage groups. There was a statistically significant difference among all groups regarding the tissue LPO levels (p<0.001). There was a statistically significant difference between the CONT-A group and the MP-A, RK-A and SK-A groups (p=0.004, p<0.001 and p=0.007, respectively) in acute stage and between the CONT-SA group and SK-SA group (p=0.002) in subacute stage. There was a statistically significant difference among all groups regarding the tissue MPO levels (p=0.001). The median MPO levels were similar among acute stage groups (p=0.057), but there was a statistical difference among subacute stage groups (p=0.046).

CONCLUSION

(S)-ketamine is more effective than methylprednisolone and racemic ketamine to reduce the LPO levels in subacute stage of spinal cord injury in rats. And, it is as effective as methylprednisolone in preventing secondary spinal cord injury histopathologically.

Cardioprotection during cardiac surgery

Coronary heart disease (CHD) is the leading cause of morbidity and mortality worldwide. For a large number of patients with CHD, coronary artery bypass graft (CABG) surgery remains the preferred strategy for coronary revascularization. Over the last 10 years, the number of high-risk patients undergoing CABG surgery has increased significantly, resulting in worse clinical outcomes in this patient group. This appears to be related to the ageing population, increased co-morbidities (such as diabetes, obesity, hypertension, stroke), concomitant valve disease, and advances in percutaneous coronary intervention which have resulted in patients with more complex coronary artery disease undergoing surgery. These high-risk patients are more susceptible to peri-operative myocardial injury and infarction (PMI), a major cause of which is acute global ischaemia/reperfusion injury arising from inadequate myocardial protection during CABG surgery. Therefore, novel therapeutic strategies are required to protect the heart in this high-risk patient group. In this article, we review the aetiology of PMI during CABG surgery, its diagnosis and clinical significance, and the endogenous and pharmacological therapeutic strategies available for preventing it. By improving cardioprotection during CABG surgery, we may be able to reduce PMI, preserve left ventricular systolic function, and reduce morbidity and mortality in these high-risk patients with CHD.

The influence of surgery on the onset of symptomatic coronary artery disease

We speculated that asymptomatic patients undergoing routine surgery might be at higher risk of subsequent cardiac events. We studied 183,534 patients with no prior admission for heart disease, aged 50-75 years, admitted electively for one of five operations considered medium to low risk of peri-operative cardiac morbidity, between January 1997 and December 2005. Controls were generated from linked records. Within 3 years 3444 (1.9%) patients undergoing operations had subsequent myocardial infarction/acute coronary syndrome (MI/ACS) compared with 3708 (2.0%) controls (p < 0.001). Overall 8406 (4.6%) patients undergoing surgery had MI/ACS compared with 9306 (5.1%) controls (p < 0.001). Of patients undergoing surgery, 20.2% died compared with 25.7% of controls (p < 0.001). Patients undergoing certain surgical procedures did not have a higher incidence of readmission for cardiac events, but had a general survival benefit compared with other elective hospital admissions. Assessment for surgery may represent a health benefit beyond the original surgery.

The effect of remote ischaemic preconditioning on myocardial injury in patients undergoing off-pump coronary artery bypass graft surgery

In several recent clinical trials on cardiac surgery patients, remote ischaemic preconditioning (RIPC) showed a powerful myocardial protective effect. However the effect of RIPC has not been studied in patients undergoing off-pump coronary artery bypass graft surgery. We evaluated whether RIPC could induce myocardial protection in off-pump coronary artery bypass graft surgery patients. Patients undergoing elective off-pump coronary artery bypass graft surgery were randomly allocated to the RIPC (n = 65) or control group (n = 65). After induction of anaesthesia, RIPC was induced by four cycles of five-minute ischaemia and reperfusion on the upper limb using a pneumatic cuff. Anaesthesia was maintained with sevoflurane, remifentanil and vecuronium. Myocardial injury was assessed by troponin I before surgery and 1, 6, 12, 24, 48 and 72 hours after surgery. There were no statistical differences in troponin I levels between RIPC and control groups (P = 0.172). Although RIPC reduced the total amount of troponin I (area under the curve of troponin increase) by 26%, it did not reach statistical significance (RIPC group 53.2 +/- 72.9 hours x ng/ml vs control group 67.4 +/- 97.7 hours x ng/ml, P = 0.281). In this study, RIPC by upper limb ischaemia reduced the postoperative myocardial enzyme elevation in off-pump coronary artery bypass graft surgery patients, but this did not reach statistical significance. Further study with a larger number of patients may be needed to fully evaluate the clinical effect of RIPC in off-pump coronary artery bypass graft surgery patients.

Effect of ketorolac and diclofenac on the impairment of endothelium-dependent relaxation induced by reactive oxygen species in rabbit abdominal aorta

Background

Reactive oxygen species (ROS) induce lipid peroxidation and tissue damage in endothelium. We studied the influences of ketorolac and diclofenac on ROS effects using the endothelium of rabbit abdominal aorta.

Methods

Isolated rabbit aortic rings were suspended in an organ bath filled with Krebs-Henseleit (K-H) solution bubbled with 5% CO₂ and 95% O₂ at 37.5℃. After being stimulated to contract with phenylephrine (PE, 10^-6 M), changes in arterial tension were recorded following the cumulative administration of acetylcholine (ACh, 3 × 10^-8 to 10^-6 M). The percentages of ACh-induced relaxation of aortic rings before and after exposure to ROS, generated by electrolysis of K-H solution, were used as the control and experimental values, respectively. The aortic rings were pretreated with ketorolac or diclofenac at the same concentrations (10^-5 M to 3 × 10^-4 M), and the effects of these agents were compared with the effects of ROS scavengers: catalase, mannitol, sodium salicylate and deferoxamine and the catalase inhibitor, 3-amino-1,2,4-triazole (3AT).

Results

Both ketorolac and diclofenac maintained endothlium-dependent relaxation induced by ACh in a dose-related manner inspite of ROS attack (P < 0.05 vs. control value). The 3AT pretreated ketorolac (3 × 10^-3 M) group was decreased more significantly than un-pretreated ketorolac (P < 0.05).

Conclusions

These findings suggest that ketorlac and diclofenac preserve the endothelium-dependent vasorelaxation against the attack of ROS, in a concentration-related manner. One of the endothelial protection mechanisms of ketorolac may be hydrogen peroxide scavenging.

Antioxidant effect of lidocaine and procaine on reactive oxygen species-induced endothelial dysfunction in the rabbit abdominal aorta

BACKGROUND

Reactive oxygen species (ROS) induce lipid peroxidation and tissue damage in the endothelium. We tested the antioxidant effect of lidocaine and procaine on ROS-induced endothelial damage in the rabbit aorta.

METHODS

Aortic rings isolated from rabbits were suspended in an organ bath filled with Krebs-Henseleit (K-H) solution bubbled with 5% CO(2) and 95% O(2) at 37.5. After precontraction with phenylephrine (PE, 10(-6) M), changes in tension were recorded following a cumulative administration of acetylcholine (ACh 3 x 10(-8) to 10(-6) M). Differences were measured as percentages of ACh-induced relaxation of aortic rings before and after exposure to ROS as generated by electrolysis of the K-H solution. The aortic rings were pretreated with lidocaine or procaine (10(-5) M to 3 x 10(-3) M) to compare their effects, as well as ROS scavengers, catalase, mannitol, sodium salicylate, and deferoxamine, and a catalase inhibitor, 3-amino-1,2,4-triazole (3AT).

RESULTS

Lidocaine and procaine dose-dependently maintained endothelium-dependent relaxation induced by ACh despite ROS activity (P < 0.05 vs control value). The 3AT pretreated procaine (3 x 10(-3) M) group decreased more significantly than the un-pretreated procaine group (P < 0.05).

CONCLUSIONS

These findings suggest that lidocaine and procaine dose-dependently preserve endothelium-dependent vasorelaxation against ROS attack, potentially via hydrogen peroxide scavenging.

Ventricular fibrillation in an ex-premature neonate following reperfusion of ischemic gut incarcerated within an inguinal hernia

We describe the case of a neonate who underwent surgery for bowel obstruction. The child was born at 25 weeks postconception, and at the time of surgery, he had a postconceptual age of 44 weeks. He had undergone two previous laparotomy procedures for necrotizing enterocolitis. At laparotomy, there was unexpected extensive compromise to gut perfusion. The child developed ventricular fibrillation following the reperfusion of a segment of ischemic gut found incarcerated in an inguinal hernial orifice. We discuss the pathophysiology of intestinal ischemia-reperfusion (I-R) injury. We have reviewed the interventions that may be employed to minimize the systemic impact of I-R.

Propofol has delayed myocardial protective effects after a regional ischemia/reperfusion injury in an in vivo rat heart model

Background

It is well known that propofol protects myocardium against myocardial ischemia/reperfusion injury in the rat heart model. The aim of this study was to investigate whether propofol provides a protective effect against a regional myocardial ischemia/reperfusion injury in an in vivo rat heart model after 48 h of reperfusion.

Methods

Rats were subjected to 25 min of left coronary artery occlusion followed by 48 h of reperfusion. The sham group received profopol without ischemic injury. The control group received normal saline with ischemia/reperfusion injury. The propofol group received profopol with ischemia/reperfusion injury. The intralipid group received intralipid with ischemia/reperfusion injury. A microcatheter was advanced into the left ventricle and the hemodynamic function was evaluated. The infarct size was determined by triphenyltetrazolium staining. The serum level of cardiac troponin-I (cTn-I) was determined by ELISA (enzyme-linked immunosorbent assay).

Results

Propofol demonstrated protective effects on hemodynamic function and infarct size reduction. In the propofol group, the +dP/d_tmax (P = 0.002) was significantly improved compared to the control group. The infarct size was 49.8% of the area at risk in the control group, and was reduced markedly by administration of propofol to 32.6% in the propofol group (P = 0.014). The ischemia/reperfusion-induced serum level of cTn-I was reduced by propofol infusion during the peri-ischemic period (P = 0.0001).

Conclusions

Propofol, which infused at clinically relevant concentration during the peri-ischemic period, has delayed myocardial protective effect after regional myocardial ischemia/reperfusion injury in an in vivo rat heart model after 48 h of reperfusion.

Xenon and isoflurane improved biventricular function during right ventricular ischemia and reperfusion

BACKGROUND

Although anesthetics have some cardioprotective properties, these benefits are often counterbalanced by their negative inotropic effects. Xenon, on the other hand, does not influence myocardial contractility. Thus, xenon may be a superior treatment for the maintenance of global hemodynamics, especially during right ventricular ischemia, which is generally characterized by a high acute complication rate.

METHODS

The effects of 70 vol% xenon and 0.9 vol% isoflurane on biventricular function were assessed in a porcine model (n=36) using the conductance catheter technique, and the expression of the type B natriuretic peptide (BNP) gene was measured. The animals underwent 90 min of right ventricular ischemia followed by 120 min of reperfusion. A barbiturate-anesthetized group was included as a control.

RESULTS

Cardiac output was compromised in unprotected animals during ischemia by 33+/-18% and during reperfusion by 53+/-17%. This was mainly due to impaired contractility in the left ventricle (LV) and increased stiffness. Isoflurane attenuated the increase in stiffness and resulted in a higher preload. In contrast, xenon increased the right ventricular afterload, which was compensated by an increase in contractility. Its effects on diastolic function were less pronounced. Upregulation of BNP mRNA expression was impeded in the remote area of the LV by both isoflurane and xenon.

CONCLUSIONS

Xenon and isoflurane demonstrated equipotent effects in preventing the hemodynamic compromise that is induced by right ventricular ischemia and reperfusion, although they acted through somewhat differential inotropic and vasodilatory effects.

Cardioprotection via modulation of calcium homeostasis by thiopental in hypoxia-reoxygenated neonatal rat cardiomyocytes

PURPOSE

Ca(2+) homeostasis plays an important role in myocardial cell injury induced by hypoxia-reoxygenation, and prevention of intracellular Ca(2+) overload is key to cardioprotection. Even though thiopental is a frequently used anesthetic agent, little is known about its cardioprotective effects, particularly in association with Ca(2+) homeostasis. We investigated whether thiopental protects cardiomyocytes against hypoxia-reoxygenation injury by regulating Ca(2+) homeostasis.

MATERIALS AND METHODS

Neonatal rat cardiomyocytes were isolated. Cardiomyocytes were exposed to different concentrations of thiopental and immediately replaced in the hypoxic chamber to maintain hypoxia. After 1 hour of exposure, a culture dish was transferred to the CO(2) incubator and cells were incubated at 37 for 5 hours. At the end of the experiments, the authors assessed cell protection using immunoblot analysis and caspase activity. The mRNA of genes involved in Ca(2+) homeostasis, mitochondrial membrane potential, and cellular Ca(2+) levels were examined.

RESULTS

In thiopental-treated cardiomyocytes, there was a decrease in expression of the proapoptotic protein Bax, caspase-3 activation, and intracellular Ca(2+) content. In addition, both enhancement of anti-apoptotic protein Bcl-2 and activation of Erk concerned with survival were shown. Furthermore, thiopental attenuated alterations of genes involving Ca(2+) regulation and significantly modulated abnormal changes of NCX and SERCA2a genes in hypoxia-reoxygenated neonatal cardiomyocytes. Thiopental suppressed disruption of mitochondrial membrane potential (DeltaPsi(m)) induced by hypoxia-reoxygenation.

CONCLUSION

Thiopental is likely to modulate expression of genes that regulate Ca(2+) homeostasis, which reduces apoptotic cell death and results in cardioprotection.

Propofol with N-acetylcysteine reduces global myocardial ischemic reperfusion injury more than ketamine in a rat model

OBJECTIVE

We examined the cardioprotective effects of propofol and ketamine with and without N-acetylcysteine (NAC).

METHODS

60 rats were divided into six groups of 10 rats each. Anesthesia induction was produced with an intraperitonal injection of ketamine in Groups 1-3 and propofol in Groups 4-6. NAC (200 mg kg(- 1)) was given intraperitonally during anesthesia induction in Groups 3 and 6. Groups 2, 3, 5, and 6 were subjected to 90 s of myocardial ischemia by clamping the ascending aorta, and then reperfusion was begun by unclamping the ascending aorta. After 60 min of reperfusion, blood samples were taken from the ascending aorta for biochemical analyses, and heart tissue samples were taken for biochemical and histopathological analyses.

RESULTS

Creatine kinase (CK), myocardial band of creatine kinase (CK-MB), and troponin-I (Tn-I) levels were significantly higher in the ischemia-reperfusion groups (2, 3, 5, 6) compared to the nonischemic groups (1, 4). CK, CK-MB, and Tn-I levels did not differ significantly between the ketamine groups (1-3) and the propofol groups (4-6) p > .05). Malondialdehyde levels were significantly higher in Groups 2 and 3 than in Group 1 and were significantly lower in Groups 4 and 6 than in Group 5 (p < .05). Malondialdehyde levels in the propofol groups (4-6) were significantly lower than in the ketamine groups (1-3; p < .05). Catalase levels in propofol groups were higher than ketamine groups. Superoxide dismutase levels were significantly higher in Group 6 than in Group 3 (p < .05).

CONCLUSIONS

In this rat model of global cardiac ischemia, propofol with NAC attenuates myocardial injury more than ketamine (with or without NAC).

Increased prevalence of metabolic syndrome in individuals with osteoarthritis: an analysis of NHANES III data

BACKGROUND

Osteoarthritis (OA) and cardiovascular disease (CVD) share age and obesity as risk factors, but may also be linked by pathogenic mechanisms involving metabolic abnormalities and systemic inflammation. This study compared the prevalence of OA and metabolic syndrome (MetS) in subjects with OA versus the general population without OA to determine whether having OA predicts increased cardiovascular risk.

METHODS

National Health and Nutrition Examination Survey III data were used as a representative sample of the general US population. Subjects included adults aged > or = 18 years with records of history, physical, radiographic, and laboratory data adequate to assess for diagnoses of MetS and OA. Logistic regression was used to examine the association between MetS and population-weighted variables.

RESULTS

The general population sample included 7714 subjects (weighted value representing 174.9 million population), of whom 975 subjects had OA (weighted value 17.5 million) and 6739 did not (weighted value 157.4 million). Metabolic syndrome was prevalent in 59% of the OA population and 23% of the population without OA. Each of the 5 cardiovascular risk factors that comprise MetS was more prevalent in the OA population versus the population without OA: hypertension (75% vs 38%), abdominal obesity (63% vs 38%), hyperglycemia (30% vs 13%), elevated triglycerides (47% vs 32%), and low high-density lipoprotein cholesterol (44% vs 38%). Metabolic syndrome was more prevalent in subjects with OA regardless of sex or race. The association between OA and MetS was greater in younger subjects and diminished with increasing age. Having OA at age 43.8 years (mean age of the general population) was associated with a 5.26-fold (SE = 1.58, P < 0.001) increased risk of MetS. This association remained strong when obesity was controlled for in additional regression models.

CONCLUSIONS

Osteoarthritis is associated with an increased prevalence of MetS, particularly in younger individuals. Global cardiovascular risk should be assessed in individuals aged < or = 65 years with OA, and should be considered when prescribing analgesics for OA patients.

Cariporide given during resuscitation promotes return of electrically stable and mechanically competent cardiac activity

Episodes of ventricular fibrillation (VF) and myocardial dysfunction commonly occur after cardiac resuscitation compromising the return of stable circulation. We investigated in a pig model of VF whether limiting Na(+)-induced cytosolic Ca(2+) overload using the sarcolemmal sodium-hydrogen exchanger isoform-1 (NHE-1) inhibitor cariporide promotes resuscitation with stable circulation.

METHODS

VF was electrically induced in 20 male pigs and left untreated for 6 min after which CPR was initiated and continued for 8 min before attempting defibrillation. Pigs were randomized to receive 3-mg/kg cariporide (n=10) or 0.9%-NaCl (n=10) before chest compression.

RESULTS

Seven of 10 pigs in each group were successfully resuscitated and survived 2h. Cariporide ameliorated post-resuscitation ventricular ectopic activity such that fewer singlets (5+/-5 vs. 26+/-21; p<0.05) and fewer bigemini (1+/-3 vs. 33+/-25; p<0.05) were observed during the initial 5 min post-resuscitation. Additionally, cariporide-treated pigs did not require additional post-resuscitation shocks for ventricular tachycardia or recurrent VF (0.0+/-0.0 vs. 5.3+/-7.8 shocks; p=0.073). During the initial 60 min cariporide-treated pigs had higher, cardiac index (6.1+/-0.7 vs. 4.4+/-1.1L/min/m(2); p<0.01), left ventricular stroke work index (45+/-9 vs. 36+/-10 gmm/beat/m(2); p<0.05), and numerically higher mean aortic pressure (104+/-11 vs. 91+/-12 mmHg; p=0.054).

CONCLUSION

Cariporide administered at the start of chest compression may help restore electrically and mechanically stable circulation after resuscitation from cardiac arrest.

The effects of NMDA receptor antagonists over intestinal ischemia/reperfusion injury in rats

Intestinal ischemia/reperfusion causes severe injury and alters motility. N-methyl-D-aspartate (NMDA) receptor antagonists have been shown to reduce ischemia/reperfusion injury in the nervous system, and in other organs. In this study, we set out to investigate the effects of NMDA receptor antagonists over intestinal ischemia/reperfusion injury. Male Wistar rats were randomly divided into four groups: (1) a control, sham-operated group; (2) an intestinal ischemia/reperfusion group subjected to 45 min ischemia and 1h reperfusion; (3) a group treated with 10 mg/kg ketamine before ischemia/reperfusion; and (4) a group treated with 10 mg/kg memantine before ischemia/reperfusion. Intestinal samples were taken for histological evaluation. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), malondialdehyde (MDA), total antioxidant capacity, tumor necrosis factor alpha (TNF-alpha), P-selectin and antithrombin III (ATIII) were measured. Intestinal transit time was determined to evaluate intestinal motility. Fecal pellet output and animal weight were also registered daily for 7 days post-ischemia. After reperfusion, AST, LDH, TNF-alpha and P-selectin levels were elevated, ATIII levels were depleted, and ALT levels were unchanged in serum. Additionally, levels of MDA were increased and total antioxidant capacity was reduced in serum, indicating oxidative stress. Intestinal mucosa showed severe injury. Ketamine, but not memantine, diminished these alterations. Intestinal motility and fecal pellet output were also altered after ischemia/reperfusion. Both drugs abolished the alterations in motility. In conclusion, ketamine's protective effects over ischemia/reperfusion do not appear to be NMDA mediated, but they could be playing a role in protecting the intestine against ischemia-induced functional changes.

The comparison of the effects of anesthetic doses of ketamine, propofol, and etomidate on ischemia-reperfusion injury in skeletal muscle

The fact that a considerable amount of clinical conditions suffering from ischemia-reperfusion injury (IRI) occur under general anesthesia has triggered researchers to focus on the effects of anesthetic drugs on IRI. Hence, the aim of this study was to compare the use of different anesthetic drugs in a skeletal IRI model. Tourniquet IRI method was performed and two experimental groups were established as sham-control and IRI group. Rats in each group were anesthetized either with thiopental, ketamine, propofol or etomidate. Malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase were measured in skeletal muscle via a spectrophotometer. Zinc, iron, copper, and selenium were evaluated by atomic absorption spectrophotometer. In rats anesthetized with thiopental (40 mg/kg, i.p.), malondialdehyde values in IRI group were higher and glutathion peroxidase levels were lower compared to sham-control group. However, superoxide dismutase and catalase activities were identical. On the other hand, while the level of zinc in IRI group attenuated, no differences in iron and copper values were determined. Rats anesthetized with ketamine (60 mg/kg), propofol (100 mg/kg), or etomidate (20 mg/kg) did not show increased malondialdehyde levels in comparison with control levels. While the drugs did not cause a distinction in the levels of superoxide dismutase, catalase, glutathion peroxidase, iron, and copper, zinc was in a lower level in IRI group compared to sham-control. In conclusion, ketamine, propofol, and etomidate, with anesthetic doses, denoted efficacious effects on IRI; hence the drugs might be preferred in certain operations with the risk of IRI.

Propofol activates and allosterically modulates recombinant protein kinase C epsilon

BACKGROUND

Myocardial protection by anesthetics is known to involve activation of protein kinase C epsilon (PKC epsilon). A key step in the activation process is autophosphorylation of the enzyme at serine 729. This study's objectives were to identify the extent to which propofol interacts with PKC epsilon and to identify the molecular mechanism(s) of interaction.

METHODS

Immunoblot analysis of recombinant PKC epsilon was used to assess autophosphorylation of PKC epsilon at serine 729 before and after exposure to propofol. An enzyme-linked immunosorbant assay kit was used for measuring PKC epsilon activity. Spectral shifts in fluorescence emission maxima of the C1B subdomain of PKC epsilon in combination with the fluorescent phorbol ester, sapintoxin D, was used to identify molecular interactions between propofol and the phorbol ester/diacylglycerol binding site on the enzyme.

RESULTS

Propofol (1 microM) caused a sixfold increase in immunodetectable serine 729 phosphorylated PKC epsilon and increased catalytic activity of the enzyme in a dose-dependent manner. Dioctanoylglycerol-induced or phorbol myristic acetate-induced activation of recombinant PKC epsilon activity was enhanced by preincubation with propofol. Both propofol and phorbol myristic acetate quenched the intrinsic fluorescence spectra of the PKC epsilon C1B subdomain in a dose-dependent manner, and propofol caused a further leftward-shift in the fluorescence emission maxima of sapintoxin D after addition of the C1B subdomain.

CONCLUSIONS

These results demonstrate that propofol interacts with recombinant PKC epsilon causing autophosphorylation and activation of the enzyme. Moreover, propofol enhances phorbol ester-induced catalytic activity, suggesting that propofol binds to a region near the phorbol ester binding site allowing for allosteric modulation of PKC epsilon catalytic activity.

Reduced release of vasoconstrictors from the porcine heart after repeated periods of ischemia

OBJECTIVE

To examine if the decline in post-ischemic hyperemic flow after repeated brief periods of myocardial ischemia is accompanied by augmented cardiac release of the vasoconstrictors endothelin-1 (ET-1) and norepinephrine (NE).

DESIGN

Mid-LAD (left anterior descending coronary artery) was occluded for 10 min with 30 min intervals a total of four times in six anesthetized pigs. Blood from the anterior interventricular coronary vein was drained through a shunt to the right atrium to facilitate blood sampling. Plasma concentrations of ET-1 and NE were repeatedly measured in arterial and coronary venous blood to estimate cardiac vasoconstrictor release.

RESULTS

Plasma concentrations of ET-1 and NE remained unaltered, but cardiac release of both vasoconstrictors rose briefly during reperfusion due to the hyperemia. However, release declined progressively after repeated periods of ischemia and reperfusion and amounted to 53% (NE) and 17% (ET-1) of initial release after the fourth period of ischemia.

CONCLUSION

The decline in post-ischemic hyperemia after repeated brief periods of myocardial ischemia is not accompanied by a progressive accentuation of cardiac ET-1 and NE release.

Anesthetic management of an off-pump open-heart surgery in a dog

OBSERVATIONS

A 9 year-old, 40 kg, female spayed Bouvier des Flandres was anesthetized for surgical removal of an intra-cardiac mass. Pre-anesthetic work-up included thoracic radiographs, which revealed moderate pleural effusion, and cardiac ultrasound, which identified a mass attached to the wall of the right ventricular outflow tract (RVOT). The mass caused dynamic obstruction of the RVOT during systole. The dog was pre-medicated with intravenous (IV) hydromorphone (0.05 mg kg(-1)). Following pre-oxygenation, anesthesia was induced with ketamine (3.75 mg kg(-1), IV) and diazepam (0.18 mg kg(-1), IV). Anesthesia was maintained with isoflurane in oxygen, an intravenous constant rate infusion (CRI) of fentanyl (10-30 microg kg(-1) hour(-1)) and a CRI of lidocaine (50-200 microg kg(-1) minute(-1)). A right lateral thoracotomy was performed. The heart was stopped transiently with a cold cardioplegic solution for 7.83 minutes to allow the removal of the mass through an open-heart procedure. No cardiopulmonary bypass was used. The heart was successfully restarted after cardiopulmonary resuscitation with internal cardiac massage and internal defibrillation. The dog recovered uneventfully from anesthesia without any apparent neurological sequelae. Post-operative analgesia consisted of intercostal nerve blocks with bupivacaine, CRIs of fentanyl (2-5 microg kg(-1) hour(-1)) and lidocaine (40 microg kg(-1) minute(-1)) and with oral meloxicam (0.1 mg kg(-1)). Five days following surgery, the dog was discharged from the hospital. Histopathology and immunohistochemistry of the mass identified an ectopic thyroid carcinoma.

CONCLUSIONS

This case showed the feasibility of whole body hypothermia and using a cold cardioplegic solution to induce cardiac arrest for a short open-heart procedure.

Propofol limits rat myocardial ischemia and reperfusion injury with an associated reduction in apoptotic cell death in vivo

Propofol, a rapidly acting, short duration, intravenous hypnotic anesthetic induction agent, is often used in clinical situations where myocardial ischemia/ reperfusion (I/R) injury is a threat. The aim of the present study was to evaluate the protective effect of propofol on myocardial I/R injury in rat due to apoptosis. Myocardial I/R injury were induced by occluding the left anterior descending (LAD) coronary artery for 25 min followed by either 2 h or 6 h reperfusion. Apoptosis was evaluated by Western blot analysis (Bcl-2, Bax expression), DNA strand breaks, TUNEL analysis and measuring myocardial caspase-3 activity. Propofol significantly reduced infarct size and improved I/R-induced myocardial contractile dysfunction by improving left ventricular diastolic pressure and positive and negative maximal values of the first derivative (+dp/dt) of left ventricular pressure. Propofol increased Bcl-2/Bax expression ratio and decreased caspase-3 activity in I/R rat hearts, which resulted in reduction of myocardial apoptosis as evidenced by TUNEL analysis and DNA laddering experiments. In an in vitro study, propofol increased H9c2 cell viability against oxidative stress induced by glucose oxidase (GOX) in a dose-dependent manner. These data suggest propofol limits I/R injury with an associated reduction in apoptotic cell death in vivo.

Pioglitazone protects the myocardium against ischemia-reperfusion injury in eNOS and iNOS knockout mice

Endothelial nitric oxide synthase (eNOS) activation with subsequent inducible NOS (iNOS), cytosolic phospholipase A2 (cPLA2), and cyclooxygenase-2 (COX2) activation is essential to statin inhibition of myocardial infarct size (IS). In the rat, the peroxisome proliferator-activated receptor-gamma agonist pioglitazone (Pio) limits IS, upregulates and activates cPLA2 and COX2, and increases myocardial 6-keto-PGF1alpha levels without activating eNOS and iNOS. We asked whether Pio also limits IS in eNOS-/- and iNOS-/- mice. Male C57BL/6 wild-type (WT), eNOS-/-, and iNOS-/- mice received 10 mg.kg(-1).day(-1) Pio (Pio+) or water alone (Pio-) for 3 days. Mice underwent 30 min coronary artery occlusion and 4 h reperfusion, or hearts were harvested and subjected to ELISA and immunoblotting. As a result, Pio reduced IS in the WT (15.4+/-1.4% vs. 39.0+/-1.1%; P<0.001), as well as in the eNOS-/- (32.0+/-1.6% vs. 44.2+/-1.9%; P<0.001) and iNOS-/- (18.0+/-1.2% vs. 45.5+/-2.3%; P<0.001) mice. The protective effect of Pio in eNOS-/- mice was smaller than in the WT (P<0.001) and iNOS-/- (P<0.001) mice. Pio increased myocardial Ser633 and Ser1177 phosphorylated eNOS levels in the WT and iNOS-/- mice. iNOS was undetectable in all six groups. Pio increased cPLA2, COX2, and PGI2 synthase levels in the WT, as well as in the eNOS-/- and iNOS-/-, mice. Pio increased the myocardial 6-keto-PGF1alpha levels and cPLA2 and COX2 activity in the WT, eNOS-/-, and iNOS-/- mice. In conclusion, the myocardial protective effect of Pio is iNOS independent and may be only partially dependent on eNOS. Because eNOS activity decreases with age, diabetes, and advanced atherosclerosis, this effect may be relevant in a clinical setting and should be further characterized.

Reaction between the anesthetic agent propofol and the free radical DPPH in semiaqueous media: kinetics and characterization of the products

The reaction of the free radical diphenylpicrylhydrazyl (DPPH ) with the anesthetic agent 2,6-diisopropylphenol (propofol, PPF) was investigated in buffered hydroalcoholic media. The kinetics was followed using a stopped-flow system. DPPH was reduced to the hydrazine analogue DPPH-H with a measured stoichiometry (DPPH /PPF) of 2. The main product of the reaction, 3,5,3',5'-tetraisopropyl-(4,4')-diphenoquinone (PPFDQ) was isolated by chromatography and its structure was fully characterized. The reaction mechanism was inferred from the stoichiometry, kinetics, and product identification. The first step, which primarily determines the kinetics, is the reaction of DPPH with PPF to produce DPPH-H and the PPF radical. The rate constant was found to be 31.8, 207, and 908 M(-1) s(-1) at pH 6.4, 7.4, and 8.4, respectively. The pH dependence is indicative of a higher reactivity of the phenolate form of PPF. Then, PPF radicals combine to form dipropofol, which is quickly oxidized to PPFDQ by the remaining DPPH . This reaction scheme is corroborated by numerical simulations of the kinetics. In the course of this study we also disclosed an unexpected effect, the photochemical degradation of PPFDQ. The need to compare antioxidants on a kinetics basis is again emphasized. In our hands, PPF presents a significantly weaker reactivity than Trolox.

Ketamine anesthesia reduces intestinal ischemia/reperfusion injury in rats

AIM: To investigate the effects of ketamine anesthesia on the motility alterations and tissue injury caused by ischemia/reperfusion in rats.

METHODS: Thirty male Wistar rats weighing 200-250 g were used. Ischemia was induced by obstructing blood flow in 25% of the total small intestinal length (ileum) with a vascular clamp for 45 min, after which either 60 min or 24 h of reperfusion was allowed. Rats were either anesthetized with pentobarbital sodium (50 mg/kg) or ketamine (100 mg/kg). Control groups received sham surgery. After 60 min of reperfusion, the intestine was examined for morphological alterations, and after 24 h intestinal basic electrical rhythm (BER) frequency was calculated, and intestinal transit determined in all groups.

RESULTS: The intestinal mucosa in rats that were anesthetized with ketamine showed moderate alterations such as epithelial lifting, while ulceration and hemorrhage was observed in rats that received pentobarbital sodium after 60 min of reperfusion. Quantitative analysis of structural damage using the Chiu scale showed significantly less injury in rats that received ketamine than in rats that did not (2.35 ± 1.14 vs 4.58 ± 0.50, P < 0.0001). The distance traveled by a marker, expressed as percentage of total intestinal length, in rats that received pentobarbital sodium was 20% ± 2% in comparison with 25.9% ± 1.64% in rats that received ketamine (P = 0.017). BER was not statistically different between groups.

CONCLUSION: Our results show that ketamine anesthesia is associated with diminished intestinal injury and abolishes the intestinal transit delay induced by ischemia/reperfusion.

[Biomedical application of electron spin resonance (ESR) spectroscopy--assessment of antioxidant property for development of drugs]

Reactive oxygen species (ROS) are associated with oxidative stress-mediated alterations under pathophysiological conditions, and particularly brain ischemia, brain tumor, and neurodegenerative diseases. Electron spin resonance (ESR) is recognized as one of the most powerful techniques available for the detection of ROS in tissues and cells. We previously developed an in vitro ESR-based technique for the detection of free radical reactions in biological systems. In addition, significant advances in the field of in vivo ESR techniques over recent years have now made it possible to visualize the distribution and metabolism of oxidative stress, and the degree of tissue oxygenation in vivo. Nitroxyl radicals are very useful as exogenous spin probes for measuring free radical distribution, oxygen concentration, and redox metabolism by in vivo ESR in biological systems, using a combination of these ESR methods collectively focused on animal models of disease such as spontaneously hypertensive rat (SHR) or stroke-prone SHR (SHRSP) for the assessment of antioxidant property of drugs. Our results suggest that ESR could be applied to the assessment of antioxidant property on oxidative stress in target organs, especially brain, using animal disease models, SHR or SHRSP. After screening drugs for antioxidant property using such as in vitro or in vivo ESR assessment, we'll be able to develop and find novel antioxidant drugs for ROS-induced brain disease in the near future.

Cardioprotection with Volatile Anesthetics in Cardiac Surgery

Myocardial ischemia during the perioperative period is a major cause of morbidity and mortality after surgery. Experimental data indicate that clinical concentrations of volatile anesthetics protect the myocardium from ischemia and reperfusion injury, as shown by decreased infarct size and more rapid postoperative recovery of contractile function. These anesthetics may also mediate protective effects in other organs, such as the brain and kidney. A number of recent reports have indicated that these experimentally observed protective effects might also be present in the clinical setting. Implementation of such cardioprotection during surgery may provide an additional tool in the treatment and prevention of ischemic cardiac dysfunction in the perioperative period. This review discusses the clinical studies that have focused on the potential cardioprotective effects of volatile anesthetic agents.

The comparative abilities of propofol and sevoflurane to modulate inflammation and oxidative stress in the kidney after aortic cross-clamping

BACKGROUND

Propofol has been reported to provide protection against ischemia-reperfusion injury. Nuclear transcription factor kappa B (NFkappaB) plays a key role in oxidative stress and the inflammatory response during ischemia-reperfusion. We compared the effect of propofol with sevoflurane on kidney NFkappaB expression and systemic inflammatory responses induced by aortic clamping.

METHODS

Twenty piglets were divided into four groups: sham surgery group with propofol (group SP, n = 5); sham group with sevoflurane (group SS, n = 5); and suprarenal clamping for 30 min with aorta-aortic bypass under propofol (group CP, n = 5) or sevoflurane (group CS, n = 5) anesthesia. Propofol was administered at 4 mg x kg(-1) x h(-1) i.v. and sevoflurane given at 1.5% inspiratory concentration. Peripheral blood and kidney biopsies were taken before the start of surgery, 15 min after unclamping the aorta, 24, 48, 72 h, and 7 days after surgery. Plasma creatinine, myeloperoxidase, tumor necrosis factor-alpha, interleukin 1-beta; and kidney superoxide anion and superoxidase dismutase were measured. The expression of inducible nitric oxide synthase and renal tissue NFkappaB was measured using Western blotting.

RESULTS

Compared with the CS group, animals in the CP group had lower concentrations of myeloperoxidase, tumor necrosis factor-alpha, interleukin 1beta, superoxide anion, superoxidase dismutase (P < 0.05) from 24 to 72 h after surgery and diminished NFkappaB expression and inducible nitric oxide synthase activity (P < 0.05) at 48 and 72 h after surgery, respectively.

CONCLUSIONS

Compared with sevoflurane, propofol administration during suprarenal aortic clamping and unclamping led to modulation of markers of inflammation and decreased NFkappaB expression.