Comparison of plasma alpha glutathione S-transferase concentrations during and after low-flow sevoflurane or isoflurane anaesthesia

Hemodynamic parameters of low-flow isoflurane and low-flow sevoflurane anesthesia during controlled ventilation with laryngeal mask airway

Background:

Nowadays laryngeal mask airway (LMA) is popular as one of the best choices for airway management. Low-flow anesthesia has some advantages like lower pollution, hemodynamic stability and cost effectiveness. Volatile anesthetics are widely used for anesthesia maintenance during operations. Sevoflurane has more hemodynamic stability compared to isoflurane, but there are few studies comparing the hemodynamic stabilities of these two anesthetics during controlled low flow anesthesia with LMA.

Objectives:

The aim of this study was to compare the effects of low-flow sevoflurane and low-flow isoflurane on hemodynamic parameters of patients through LMA.

Patients and Methods:

Eighty patients, scheduled for elective ophthalmic surgery, were randomly divided into two groups. After induction, an LMA with an appropriate size was inserted in all the patients and they were randomly allocated to two groups of low-flow sevoflurane (n = 40) and low-flow isoflurane (n = 40). Hemodynamic parameters (heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and Mean Arterial Pressure (MAP) were recorded at 5, 10, 15, 20, 25 and 30 minutes after the anesthesia induction.

Results:

The mean heart rate values were significantly less in the sevoflurane group (P value < 0.05) at 25 minutes after the surgery. The mean Blood Pressure in the isoflurane group was significantly higher compared with the sevoflurane group in 10, 20 and 30 minutes after the surgery (P values = 0.0131, 0.0373 and 0.0028, respectively). These differences were clinically unimportant because heart rate and mean blood pressure were on normal ranges.

Conclusions:

Seemingly, low-flow sevoflurane with LMA did not have any significant hemodynamic effect on clinical practice. Therefore, low-flow sevoflurane anesthesia with LMA might be considered in patients with short operations who need rapid recovery from anesthesia.

Impact of biomarker development on drug safety assessment

Drug safety has always been a key aspect of drug development. Recently, the Vioxx case and several cases of serious adverse events being linked to high-profile products have increased the importance of drug safety, especially in the eyes of drug development companies and global regulatory agencies. Safety biomarkers are increasingly being seen as helping to provide the clarity, predictability, and certainty needed to gain confidence in decision making: early-stage projects can be stopped quicker, late-stage projects become less risky. Public and private organizations are investing heavily in terms of time, money and manpower on safety biomarker development. An illustrative and "door opening" safety biomarker success story is the recent recognition of kidney safety biomarkers for pre-clinical and limited translational contexts by FDA and EMEA. This milestone achieved for kidney biomarkers and the "know how" acquired is being transferred to other organ toxicities, namely liver, heart, vascular system. New technologies and molecular-based approaches, i.e., molecular pathology as a complement to the classical toolbox, allow promising discoveries in the safety biomarker field. This review will focus on the utility and use of safety biomarkers all along drug development, highlighting the present gaps and opportunities identified in organ toxicity monitoring. A last part will be dedicated to safety biomarker development in general, from identification to diagnostic tests, using the kidney safety biomarkers success as an illustrative example.

No elevation of glutathione S-transferase-a1-1 by amiodarone loading in intensive care unit patients with atrial fibrillation

Hepatocellular toxicity is a putative side-effect of amiodarone. The hepatic detoxification enzyme glutathione S-transferase-A1-1 (GSTA1-1) is a sensitive indicator of hepatocellular damage. We investigated the occurrence of subclinical liver injury, as measured by plasma GSTA1-1 in intensive care unit patients with atrial fibrillation receiving amiodarone. Sixteen haemodynamically stable intensive care unit patients with atrial fibrillation were treated with amiodarone intravenously. Patients were given a loading dose of 150 mg followed by another 150 mg followed by a continuous infusion of 1200 mg/hour if atrial fibrillation persisted. Blood samples for GSTA1-1 (measured by an enzyme-linked immunosorbent assay) were taken at zero, one, three, six, 12 and 24 hours, transaminases and bilirubin at zero, six, 12 and 24 hours. Blood pressure and heart rate were continuously monitored. Effects were analysed for time-dependent changes (one-way analysis of variance for repeated measures). Blood pressure increased from 125 +/- 8/60 +/- 3 mmHg at t = 0 to 144 +/- 9/66 +/- 4 mmHg at t = 24 hours (P < 0.05), heart rate decreased from atrial fibrillation 124 +/- 5 to sinus rhythm 86 +/- 6 beats per minute (P < 0.05). There was no significant elevation of GSTA1-1, transaminases or bilirubin during the observation period of 24 hours. Amiodarone does not cause elevation of GSTA1-1 as a marker of subclinical liver injury in haemodynamically stable intensive care unit patients with atrial fibrillation.

Association between GSTP1 gene polymorphism and serum α-GST concentrations undergoing sevoflurane anaesthesia

BACKGROUND AND OBJECTIVES

The measurement of alpha-glutathione-S-transferase enzyme is one of the most sensitive indicators of hepatocellular function. Variation in the glutathione-S-transferase P1 gene clusters has been intensively investigated and polymorphism has been described. The aim of the study was to assess whether an association exists between glutathione-S-transferase P1 gene polymorphism and serum alpha-glutathione-S-transferase concentrations for the first postoperative day in patients who underwent anaesthesia with sevoflurane.

METHODS

In all, 54 unrelated patients were enrolled in this study. Anaesthesia was induced with thiopental and fentanyl. Vecuronium was used for neuromuscular relaxation before endotracheal intubation. Anaesthesia was maintained with sevoflurane in a gas mixture containing 50% nitrous oxide in oxygen. Peripheral venous blood samples to determine serum alpha-glutathione-S-transferase concentrations were collected before induction (T1), at the end of anaesthesia (T2) and at 24-h postoperatively (T3). Enzyme-linked immunosorbent assay (ELISA) immunoassay was used to measure alpha-glutathione-S-transferase levels. Genomic DNA was isolated from serum samples using a genomic DNA purification kit. In order to detect the variants of glutathione-S-transferase P1, polymerase chain reaction-restriction fragment length polymorphism analysis was employed.

RESULTS

Early postoperative serum alpha-glutathione-S-transferase levels for all patients were significantly increased when compared with preanaesthetic and 24-h postoperatively (P 0.05).

CONCLUSIONS

Although alpha-glutathione-S-transferase levels were elevated in all patients after sevoflurane anaesthesia, levels remained high at 24 h in patients with glutathione-S-transferase P1 Ile105Val genotypes compared to controls.

Alpha-gluthathione S-transferase as an early marker of hepatic ischemia/reperfusion injury after liver resection

Organ dysfunction following liver resection is one of the major postoperative complications of liver surgery. The Pringle maneuver is often applied during liver resection to minimize bleeding, which in turn complicates the postoperative course owing to liver ischemia and reperfusion. Routinely, hepatocellular damage is diagnosed by, for example, abnormal aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and the prothrombin time (PT). The cytosolic liver enzyme alpha-glutathione S-transferase (alpha-GST) has recently been shown to have good sensitivity for detecting hepatic injury after acetaminophen poisoning or liver transplantation, but its role in non-transplantation liver surgery has not been assessed. In this prospective randomized clinical study, the diagnostic role of plasma alpha-GST following warm ischemia and reperfusion is reported. A total of 75 patients who underwent liver resection were randomly assigned to three groups: (1) without Pringle (NPR); (2) with Pringle (PR); (3) with ischemic preconditioning by 10 minutes of ischemia and reperfusion each prior to the Pringle manuever (IPC). The major findings are as follows: (1) ALT, AST, and alpha-GST increased upon liver manipulation as early as prior to resection, with a rapid return of alpha-GST values to preoperative levels, whereas ALT and AST further increased on the first postoperative day. (2) In the PR group, alpha-GST, but not ALT and AST, was significantly elevated compared with that in the NPR group at 15 and 30 minutes and 2 hours after resection/reperfusion. In addition, only levels of alpha-GST significantly correlated with the Pringle duration. (3) The ischemia/reperfusion-induced early rise in alpha-GST was completely prevented by ischemic preconditioning. Moreover, only alpha-GST concentrations (> 490 microg L(-1)) determined early after resection (2 hours) predicted postoperative liver dysfunction (24 hours PT < 60%) with a positive predictive value of 74% and a negative predictive value of 76%. Thus alpha-GST seems to be a sensitive, predictive marker of ischemia/reperfusion-induced hepatocellular injury and postoperative liver dysfunction.