The effects of etomidate on expression of high mobility group box 1 via the nuclear factor kappa B pathway in rat model of sepsis

Etomidate is an anesthetic agent used in hemodynamically unstable patients, but its use has been controversial in septic patients. The response of high-mobility group box 1 (HMGB1), a late-phase lethal cytokine in sepsis, to etomidate has not been reported. This study investigated the effects of etomidate on the expression and release of HMGB1 and the underlying mechanism using a cecal ligation and puncture (CLP) model. Thirty-six male Sprague-Dawley rats were divided into sham, CLP, and Etomi groups. Sepsis was induced in the CLP and Etomi groups, and intravenous etomidate (4 mg/kg) was infused for 40 min immediately after operation in the Etomi group. Serum creatinine, alanine aminotransferase (ALT), tumor necrosis factor (TNF)-α, interleukin (IL)-6, and HMGB1 levels were measured 6 and 24 hours after surgery. Activation of nuclear factor (NF)-ĸB and HMGB1 mRNA expression in the liver, lung, kidney, and ileum tissues were measured, and immunohistochemical staining of HMGB1 was implemented. Increases of the TNF-α level 6 h after CLP and ALT and IL-6 levels 24 h after CLP were significantly inhibited by etomidate treatment. Etomidate treatment also significantly attenuated the increase in serum HMGB1 level at 6 and 24 h after CLP and suppressed the NF-ĸB and HMGB1 mRNA in multiple organs 24 h after CLP. Immunohistochemical staining also revealed that etomidate treatment inhibited HMGB1 expression. Etomidate inhibited the systemic release of HMGB1 and its expression in various organs. The mechanism may be associated with the inhibitory effects of etomidate on pro-inflammatory cytokine release and NF-ĸB activity.

Comparison of the efficacy of erector spinae plane block according to the difference in bupivacaine concentrations for analgesia after laparoscopic cholecystectomy: a retrospective study

BACKGROUND

Laparoscopic cholecystectomy (LC) is a noninvasive surgery, but postoperative pain is a major problem. Studies have indicated that erector spinae plane block (ESPB) has an analgesic effect after LC. We aimed to compare the efficacy of different ESPB anesthetic concentrations in pain control in patients with LC.

METHODS

This retrospective study included patients aged 20 to 75 years scheduled for LC with the American Society of Anesthesiologists physical status classification I or II. ESPB was administered using 0.375% bupivacaine in group 1 and 0.25% in group 2. Both groups received general anesthesia. Postoperative tramadol consumption and pain scores were compared and intraoperative and postoperative fentanyl requirements in the postanesthesia care unit (PACU) were measured.

RESULTS

Eighty-five patients were included in this analysis. Tramadol consumption in the first 12 hours, second 12 hours, and total 24 hours was similar between groups (p>0.05). The differences between postoperative numeric rating scale (NRS) scores at rest did not differ significantly. The postoperative NRS scores upon bodily movement were not statistically different between the two groups, except at 12 hours. The mean intraoperative and postoperative fentanyl requirements in the PACU were similar. The difference in the requirement for rescue analgesics was not statistically significant (p=0.788).

CONCLUSION

Ultrasound-guided ESPB performed with different bupivacaine concentrations was effective in both groups for LC analgesia, with similar opioid consumption. A lower concentration of local anesthetic can be helpful for the safety of regional anesthesia and is recommended for the analgesic effect of ESPB in LC.

Bilateral posterior cerebral artery stroke following transtentorial herniation caused by a subependymal giant cell astrocytoma in a patient with tuberous sclerosis: a case report

Background: Acute increased intracranial pressure (IICP) is a life-threatening condition that requires urgent treatment. Rapid IICP with hydrocephalus may be complicated by ischemic stroke, convulsions, loss of consciousness, brain herniation, and death. Extremely rare complications include intracranial vessel entrapment and ischemic stroke due to sudden IICP in cases with benign tumors. Case Report: We report a case of bilateral posterior cerebral artery region infarction and complicated hydrocephalus with subependymal giant cell astrocytoma in a patient with tuberous sclerosis. Conclusion: We postulate that the temporary IICP induced by seizure led to transient bilateral posterior cerebral artery entrapment, causing ischemic stroke without vascular occlusion.

Amitriptyline inhibits the MAPK/ERK and CREB pathways and proinflammatory cytokines through A3AR activation in rat neuropathic pain models

Background

The pain-relief properties of tricyclic antidepressants can be attributed to several actions. Recent observations suggest that adenosine is involved in the antinociceptive effect of amitriptyline. The A3 adenosine receptor (A3AR) is the only adenosine subtype overexpressed in inflammatory and cancer cells. This study was performed to investigate the role of A3AR in the anti-nociceptive effect of amitriptyline.

Methods

Spinal nerve-ligated neuropathic pain was induced by ligating the L5 and L6 spinal nerves of male Sprague-Dawley rats. The neuropathic rats were randomly assigned to one of the following three groups (8 per group): a neuropathic pain with normal saline group, a neuropathic pain with amitriptyline group, and a neuropathic pain with amitriptyline and 3-ethyl-5-benzyl- 2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate (MRS) group. Amitriptyline or saline was administered intraperitoneally and 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate (MRS-1191), an A3AR antagonist, was injected subcutaneously immediately before amitriptyline administration. The level of extracellular signal-regulated kinase P44/42 (ERK1/2), cyclic AMP response element-binding protein (CREB), and proinflammatory cytokines were assessed using immunoblotting or reverse-transciption polymerase chain reaction.

Results

Amitriptyline increased the mechanical withdrawal threshold of the neuropathic rats. The level of phospho-ERK1/2 and phospho-CREB proteins, and proinflammatory cytokines produced by spinal nerve ligation were significantly reduced by amitriptyline administration. However, the use of MRS-1191 before amitriptyline administration not only reduced the threshold of mechanical allodynia, but also increased the signaling protein and proinflammatory cytokine levels, which were reduced by amitriptyline.

Conclusions

The results of this study suggest that the anti-nociceptive effect of amitriptyline involves the suppression of ERK1/2 and CREB signaling proteins, and A3AR activation also affects the alleviation of the inflammatory response.

Optimal neuromuscular blocking effects of remifentanil during tracheal intubation under general anesthesia

Objective

This study was performed to determine the effect of the remifentanil dose on the onset time of rocuronium with electromyography.

Methods

This retrospective comparative study included 75 patients undergoing general anesthesia for elective surgery. Patients received lidocaine (40 mg) and propofol (2 mg/kg) followed by rocuronium (0.6 mg/kg) with either saline infusion (Group S), remifentanil at 0.5 µg/kg/minute (Group R 0.5), or remifentanil at 1.0 µg/kg/minute (Group R 1.0). Neuromuscular block was monitored by train-of-four (TOF) electromyography, and the times taken to reach TOF 0 and TOF ratio (TOFR) 25% were recorded.

Results

The times taken to reach TOF 0 and TOFR 25% were significantly higher in Groups R 0.5 and R 1.0 than in Group S. The time taken to reach TOF 0 was 130.0 ± 6.4 s in Group S, 142.6 ± 6.0 s in Group R 0.5, and 183.0 ± 11.6 s in Group R 1.0. The time taken to reach TOFR 25% was also higher in Groups R 0.5 and R 1.0 than in Group S.

Conclusions

As the remifentanil dose increases, the intubation time required to reach TOF 0 also increases. Remifentanil has an effect on the onset of rocuronium.

Optic Nerve Sheath Meningioma: Preliminary Analysis of the Role of Radiation Therapy

Background

The purpose of this study was to evaluate the treatment outcome of our optic nerve sheath meningioma (ONSM) case series in terms of preventing tumor growth and preserving vision in ONSM patients.

Methods

Between July 2003 and March 2015, 1,398 patients with intracranial meningioma were diagnosed at Seoul National University Bundang Hospital. Among them, only 13 patients (0.93%) were diagnosed with ONSM and enrolled in the present study. Tumor volume changes of ONSM patients and their visual acuity were evaluated before and after treatments.

Results

The median follow-up time was 50 months (range, 12–133 months). Visual acuity was evaluated in 12 of 13 patients, and visual acuity was found to be preserved in 9 of 12 patients (75%). Tumor volume was reduced in all patients. The tumor control rate was 100% in the present study. The difference in tumor volume between pretreatment and last follow-up was statistically significant (p=0.015).

Conclusion

Intensity-modulated radiotherapy (IMRT) and gamma knife radiosurgery (GKS) could maintain visual acuity and stabilize tumor volume in ONSM patients, suggesting that IMRT and GKS may be effective therapies for ONSM. However, which treatment is the more effective modality must be confirmed by prospective studies and longer-term follow-up.

The Effects of Remifentanil on Expression of High Mobility Group Box 1 in Septic Rats

High mobility group box 1 (HMGB1) is a pivotal mediator of sepsis progression. Remifentanil, an opioid agonist, has demonstrated anti-inflammatory effects in septic mice. However, it is not yet known whether remifentanil affects the expression of HMGB1. We investigated the effects of remifentanil on HMGB1 expression and the underlying mechanism in septic rats. Forty-eight male Sprague-Dawley rats were randomly divided into 3 groups; a sham group, a cecal ligation and puncture (CLP) group, and a CLP with remifentanil treatment (Remi) group. The rat model of CLP was used to examine plasma concentrations of proinflammatory cytokines, tissue HMGB1 mRNA and the activity of nuclear factor (NF)-κB in the liver, lungs, kidneys, and ileum. Pathologic changes and immunohistochemical staining of NF-κB in the liver, lungs, and kidneys tissue were observed. We found that remifentanil treatment suppressed the level of serum interleukin (IL)-6 and tumor necrosis factor (TNF)-α 6 hours after CLP, and serum HMGB1 24 hours after CLP. HMGB1 mRNA levels and the activity of NF-κB in multiple organs decreased by remifentanil treatment 24 hours after CLP. Remifentanil treatment also attenuated nuclear expression of NF-κB in immunohistochemical staining and mitigated pathologic changes in multiple organs. Altogether, these results suggested that remifentanil inhibited expression of HMGB1 in vital organs and release of HMGB1 into plasma. The mechanism was related to the inhibitory effect of remifentanil on the release of proinflammatory cytokines and activation of NF-κB.

Comparison of an Intraoperative Infusion of Dexmedetomidine, Fentanyl, and Remifentanil on Perioperative Hemodynamics, Sedation Quality, and Postoperative Pain Control

We aimed to compare fentanyl, remifentanil and dexmedetomidine with respect to hemodynamic stability, postoperative pain control and achievement of sedation at the postanesthetic care unit (PACU). In this randomized double-blind study, 90 consecutive total laparoscopic hysterectomy patients scheduled for elective surgery were randomly assigned to receive fentanyl (1.0 μg/kg) over 1 minute followed by a 0.4 μg/kg/hr infusion (FK group, n = 30), or remifentanil (1.0 μg/kg) over 1 minute followed by a 0.08 μg/kg/min infusion (RK group, n = 30), or dexmedetomidine (1 μg/kg) over 10 minutes followed by a 0.5 μg/kg/hr infusion (DK group, n = 30) initiating at the end of main procedures of the operation to the time in the PACU. A single dose of intravenous ketorolac (30 mg) was given to all patients at the end of surgery. We respectively evaluated the pain VAS scores, the modified OAA/S scores, the BIS, the vital signs and the perioperative side effects to compare the efficacy of fentanyl, remifentanil and dexmedetomidine. Compared with other groups, the modified OAA/S scores were significantly lower in DK group at 0, 5 and 10 minutes after arrival at the PACU (P < 0.05), whereas the pain VAS and BIS were not significantly different from other groups. The blood pressure and heart rate in the DK group were significantly lower than those of other groups at the PACU (P < 0.05). DK group, at sedative doses, had the better postoperative hemodynamic stability than RK group or FK group and demonstrated a similar effect of pain control as RK group and FK group with patient awareness during sedation in the PACU. (World Health Organization registry, KCT0001524).

Aminophylline partially prevents the decrease of body temperature during laparoscopic abdominal surgery

Aminophylline can elicit thermogenesis in rats or increase metabolic rate during cold stress in lambs. We tested the hypothesis that aminophylline would reduce the change in core body temperature during laparoscopic abdominal surgery requiring pneumoperitoneum. Fifty patients were randomly divided into an aminophylline group (n=25) and a saline control group (n=25). Esophageal temperature, index finger temperature, and hemodynamic variables, such as mean blood pressure and heart rate, were measured every 15 min during sevoflurane anesthesia. In the aminophylline group, esophageal temperatures at T45 (36.1±0.38 vs. 35.7±0.29, P=0.024), T60 (36.0±0.39 vs. 35.6±0.28, P=0.053), T75 (35.9±0.34 vs. 35.5±0.28, P=0.025), T90 (35.8±0.35 vs. 35.3±0.33, P=0.011), and T105 (35.8±0.36 vs. 35.1±0.53, P=0.017) and index finger temperatures at T15 (35.8±0.46 vs. 34.9±0.33, P<0.001), T30 (35.7±0.36 vs. 35.0±0.58, P=0.029), T45 (35.8±0.34 vs. 35.2±0.42, P=0.020), T60 (35.7±0.33 vs. 34.9±0.47, P=0.010), T75 (35.6±0.36 vs. 34.8±0.67, P=0.028), T90 (35.4±0.55 vs. 34.4±0.89, P=0.042), and T105 (34.9±0.53 vs. 33.9±0.85, P=0.024) were significantly higher than in the saline control group. Aminophylline is effective in maintaining the core temperature through a thermogenic effect, despite reduced peripheral thermoregulatory vasoconstriction.

Comparison of the recovery and respiratory effects of aminophylline and doxapram following total intravenous anesthesia with propofol and remifentanil

STUDY OBJECTIVE

To compare the effects of aminophylline and doxapram on recovery, respiration, and bispectral index (BIS) values in patients after total intravenous anesthesia (TIVA) with propofol and remifentanil.

DESIGN

Prospective, randomized, blinded clinical trial.

SETTING

Operating room of a university hospital.

PATIENTS

90 adult, ASA physical status 1 and 2 patients scheduled for elective laparoscopic vaginal hysterectomy.

INTERVENTIONS

TIVA was performed with the induction target of remifentanil 3 ng/mL and propofol 6 μg/mL, followed by the maintenance target of remifentanil 1-3 ng/mL and propofol 3-5 μg/mL at the effect site, and with BIS scores in 40-50 range. Patients were randomized to three groups to receive intravenous (IV) aminophylline 3 mg/kg (n = 30), IV doxapram 1 mg/kg (n = 30), or normal IV saline (control; n = 30).

MEASUREMENTS AND MAIN RESULTS

After administration of the study drugs, return to spontaneous ventilation differed significantly among the three groups. The times to eye opening and hand squeezing on verbal command were similar. The time to extubation was shortened in both the doxapram and aminophylline groups (P < 0.05). Tidal volumes were increased in the doxapram group at 5-14 minutes and the aminophylline group at 5-12 minutes (P < 0.05). Respiratory rates were increased at 2 to 8 minutes and then showed a decrease at the 12 to 14-minute mark in both the doxapram and aminophylline groups (P < 0.05). No difference was noted between the two groups. BIS values were increased in both the doxapram and aminophylline groups at 4-10 minutes (P < 0.05). Heart rates were increased in the doxapram group for the first 8 minutes and at 1-2 minutes in the aminophylline group (P < 0.05).

CONCLUSION

Aminophylline 3 mg/kg or doxapram 1 mg/kg shortened the time to spontaneous ventilation and improved early recovery from TIVA without appreciable side effects. The more rapid emergence correlates with higher BIS values when compared with the saline control group. The arousal and respiratory effects of aminophylline were comparable to those of doxapram.

Hepatic ischemic preconditioning provides protection against distant renal ischemia and reperfusion injury in mice

We previously demonstrated that there are acute and delayed phases of renal protection against renal ischemia and reperfusion (IR) injury with renal ischemic preconditioning (IPC). This study assessed whether hepatic IPC could also reduce distant renal IR injury through the blood stream-mediated supply of reactive oxygen species (ROS). Male C57BL/6 mice were randomly divided into four groups: group I, sham operated including right nephrectomy; group II (IR), left renal ischemia for 30 min and reperfusion injury; group III (IPC-IR), hepatic ischemia for 10 min followed by 10 min of reperfusion before left renal IR injury; group IV (MPG - IPC + IR), pretreated with 100 mg/kg N-(2-mercaptopropionyl)-glycine (MPG) 15 min before hepatic IPC and left renal IR injury. Renal function, histopathologic findings, proinflammatory cytokines, and cytoprotective proteins were evaluated 15 min or 24 hr after reperfusion. Hepatic IPC attenuated the expression of proinflammatory cytokines, tumor necrosis factor α, intercellular adhesion molecule 1, and induced inducible nitric-oxide synthase, and the phosphorylation of Akt in the murine kidney. Renal function was better preserved in mice with hepatic IPC (group III) than groups II or IV. Hepatic IPC protects against distant renal IR injury through the blood stream-delivery of hepatic IPC-induced ROS, by inducing cytoprotective proteins, and by inhibiting inflammatory reactions.

Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study

PURPOSE

Pain in terminal cancer patients may be refractory to systemic analgesics or associated with adverse drug reactions to analgesics. Epidural analgesia has been effectively used in such patients for pain control. However, this method does not provide pain relief to all patients. The efficacy and complications of continuous epidural analgesia were evaluated for expanding efficacy in terminal cancer patients.

MATERIALS AND METHODS

The charts of patients who received epidural analgesia for over 5 years for the control of terminal cancer pain were reviewed retrospectively.

RESULTS

Ninety-six patients received 127 epidural catheters. The mean duration for epidural catheterization was 31.5±55.6 (5-509) days. The dose of epidural morphine increased by 3.5% per day. The efficacy of epidural analgesia at 2 weeks follow up revealed improved pain control (n=56), as the morphine equivalent drug dose dropped from 213.4 mg/day to 94.1 mg/day (p<0.05) at 2 weeks follow up. Accordingly, after 2 weeks institution of epidural analgesia, there was a significant reduction in the proportion of patients with severe pain, from 78.1% to 19.6% (p<0.05).

CONCLUSION

Epidural analgesia was an effective pain control method in patients with terminal cancer pain, however, a systematized algorithm for the control of cancer-related pain in needed.

Comparison of an Intraoperative Infusion of Dexmedetomidine or Remifentanil on Perioperative Haemodynamics, Hypnosis and Sedation, and Postoperative Pain Control

This prospective, randomized, double-blind study compared the effects of dexmedetomidine and remifentanil on haemodynamic stability, sedation and postoperative pain control in the postanaesthetic care unit (PACU). Fifty consecutive patients scheduled for total laparoscopic hysterectomy were randomly assigned to receive infusions of either dexmedetomidine (1 μg/kg) i.v. over 10 min followed by 0.2-0.7 μg/kg per h continuous i.v. infusion or remifentanil (0.8-1.2 μg/kg) i.v. over 1 min followed by 0.05-0.1 μg/kg i.v. per min, starting at the end of surgery to the time in the PACU. Modified observer's assessment of alertness scores were significantly lower in the dexmedetomidine group than in the remifentanil group at 0, 5 and 10 min after arrival in the PACU. Blood pressure and heart rate in the dexmedetomidine group were significantly lower than that recorded in the remifentanil group in the PACU. Dexmedetomidine, at the doses used in this study, had a significant advantage over remifentanil in terms of postoperative haemodynamic stability.

Comparison of Stress Hormone Response, Interleukin-6 and Anaesthetic Characteristics of Two Anaesthetic Techniques: Volatile Induction and Maintenance of Anaesthesia using Sevoflurane versus Total Intravenous Anaesthesia using Propofol and Remifentanil

This prospective randomized study compared the effects of two types of anaesthesia on peri-operative anaesthetic profiles from induction to recovery and on immunological and neurohormonal responses to anaesthesia and surgical stress. Forty patients were assigned to undergo either volatile induction and maintenance of anaesthesia (VIMA) with sevoflurane or total intravenous anaesthesia (TIVA) with propofol and remifentanil. Plasma adrenaline, noradrenaline, cortisol, glucose and interleukin-6 (IL-6) levels were measured at baseline, induction, incision and extubation. TIVA produced a significantly lower intubation score, shorter time to intubation and faster waking time than VIMA, but recovery profiles did not differ. Adrenaline, noradrenaline, cortisol and glucose levels were significantly lower with TIVA than VIMA, but there was no difference in IL-6 levels between the two groups. TIVA with propofol and remifentanil may be preferable to VIMA with sevoflurane alone because it leads to smoother, more rapid induction, more rapid awakening and lower stress responses to surgical stimuli.

The use of intra-cellular signaling pathways in anesthesiology and pain medicine field

At the level of individual cells, signaling is crucial in cell division, differentiation, metabolic control and death. Reception of the signals depends on receptor proteins that are usually at the cell surface, and these receptor proteins bind the signal molecule. The binding activates the receptor, which in turn activates one or more of the intra-cellular signaling pathways. These relay chains of molecules, mainly intra-cellular signaling proteins, process the signal inside the receiving cell and distribute it to the appropriate intra-cellular targets. Cell signaling pathways are involved in the pathophysiology of many diseases and also in the mechanisms of action of many drugs, including local and general anesthetics. Knowledge of the basic cell signaling mechanisms is essential for understanding many of the pathophysiologic and pharmacologic mechanisms. Therefore, if we focus on applying the new cellular and molecular biologic research, these efforts could identify the mechanism of diseases and help develop new drugs in the field of anesthesiology and pain medicine.

Lidocaine attenuates the expression of ERK1/2 and CREB in a neuropathic pain model of rats

BACKGROUND

In addition to causing the loss of voluntary sensory and motor function, spinal cord injury (SCI) often creates a state of central neuropathic pain. Rats given SCI display increases in the activated form of transcription factors ERK 1/2, p38 MAPK, and CREB in the spinal cord, which correspond to allodynia in a model of neuropathic pain. The current study was designed to determine if lidocaine had an effect on the development of neuropathic pain in response to SCI.

METHODS

Male Sprague Dawley rats were anesthetized and then received a L5-L6 spinal nerve ligation (neuropathic rats). The levels of intracellular cell-signaling protein, ERK 1/2 and CREB were then assessed by western blot analysis of samples collected from a sham operated (control) group, a neuropathic pain and normal saline (NP + NS) group, and a neuropathic pain and 5% lidocaine (NP + Lido) group.

RESULTS

The increased levels of ERK 1/2 and CREB protein that were observed in the neuropathic pain model were reduced by continuous infusion of 5% lidocaine.

CONCLUSIONS

The current results suggest that lidocaine therapy may be an effective method of preventing and treating central neuropathic pain following SCI, and that these effects may occur via the reduced expression of ERK 1/2 and CREB in the intracellular cell-signaling pathway.

Comparison of Three Warming Devices for the Prevention of Core Hypothermia and Post-Anaesthesia Shivering

The efficacy of forced air warming with a surgical access blanket in preventing a decrease in core temperature during anaesthesia and post-anaesthesia shivering (PAS) was compared with two widely used interventions comprising forced air warming combined with an upper body blanket, and a circulating water mattress, in a prospective, randomized double-blind study. A total of 90 patients undergoing total abdominal hysterectomy were studied, 30 in each group. Core temperature was measured 15, 30, 45, 60, 90 and 120 min after induction of anaesthesia. PAS was evaluated every 5 min after emergence from anaesthesia over a period of 1 h. Core temperature fell in all three groups compared with the baseline, but forced air warming using a surgical access blanket was more effective than the other warming methods in ameliorating the temperature decrease. The surgical access blanket was also superior to the circulating water mattress in reducing PAS.

Acute and delayed renal protection against renal ischemia and reperfusion injury with A1adenosine receptors

We showed previously that activation of A1adenosine receptors (AR) protects against renal ischemia-reperfusion (IR) injury in rats and mice. In the heart, transient A1AR activation produces biphasic protective effects: acute protection wanes after several hours but protective effects return 24–72 h later (second window of protection). In this study, we determined whether A1AR activation produces delayed renal protection and elucidated the mechanisms of acute and delayed renal protection. A1AR wild-type mice were subjected to 30-min renal ischemia and 24 h of reperfusion to produce acute renal failure. Pretreatment with a selective A1AR agonist 2-chloro- N6-cyclopentyladenosine (CCPA; 0.1 mg/kg bolus ip) either 15 min or 24 h before renal ischemia protected against renal IR injury and reduced renal corticomedullary necrosis, apoptosis, and inflammation. Transient A1AR activation led to phosphorylation of extracellular signal-regulated protein kinase mitogen-activated protein kinase (ERK MAPK), Akt, and heat shock protein 27 (HSP27). Moreover, induction of HSP27 and Akt occurred with CCPA treatment. Inhibition of PKC with chelerythrine prevented acute but not delayed renal protection with A1AR activation. Moreover, deletion of PI3Kγ or inhibition of Akt, but not inhibition of ERK, prevented delayed and acute renal protection with A1AR activation. Inhibition of Gi/owith pertussis toxin obliterated both acute and delayed A1AR-mediated renal protection. In contrast to renal protection with delayed ischemic preconditioning, nitric oxide synthase activity was not induced with delayed A1AR-mediated renal protection. Therefore, transient activation of renal A1AR led to acute as well as delayed protective effects against renal IR injury via distinct signaling pathways.

Isoflurane improves survival and protects against renal and hepatic injury in murine septic peritonitis

We have demonstrated that volatile anesthetics reduce inflammation after renal ischemia/reperfusion injury in vivo. As hyperactive uncontrolled inflammation can lead to mortality and morbidity during early sepsis, we questioned whether the volatile anesthetic isoflurane could reduce mortality and protect against sepsis induced renal and hepatic dysfunction. Mice were anesthetized with isoflurane or with pentobarbital and subjected to cecal ligation and puncture (CLP) to induce septic peritonitis. Mice were anesthetized for an additional 3 h after CLP with either isoflurane or pentobarbital. Renal and hepatic function was assessed 24 h later and survival after CLP was assessed for 7 days. To determine if isoflurane protects by reducing inflammation, we quantified renal tubular expression of pro-inflammatory (intercellular adhesion molecule 1, tumor necrosis factor alpha [TNF-alpha], and interleukin [IL] 1beta) messenger RNA with reverse transcriptase-polymerase chain reaction. We also measured the plasma levels of the pro-inflammatory cytokines TNF-alpha, keratinocyte-derived chemokine (KC), and IL-6 and an anti-inflammatory cytokine IL-10. Renal cortical apoptosis was also assessed 24 h after CLP. Twenty-four hours after the septic insult, isoflurane-treated mice had significantly improved renal and hepatic function compared with mice anesthetized with pentobarbital. Renal cortices of isoflurane-treated mice had significantly reduced expression of intercellular adhesion molecule 1, TNF-alpha, and IL-1beta messenger RNA and showed less apoptosis. Isoflurane-treated mice had lower plasma levels of TNF-alpha, KC, and IL-6. Isoflurane-anesthetized mice also had significantly prolonged and increased survival compared with pentobarbital-anesthetized mice. Therefore, isoflurane anesthesia conferred significant protection against renal and hepatic dysfunction and death after septic peritonitis and attenuated renal inflammation and apoptosis compared with pentobarbital anesthesia.

Ischemic preconditioning provides both acute and delayed protection against renal ischemia and reperfusion injury in mice

Acute as well as delayed ischemic preconditioning (IPC) provides protection against cardiac and neuronal ischemia reperfusion (IR) injury. This study determined whether delayed preconditioning occurs in the kidney and further elucidated the mechanisms of renal IPC in mice. Mice were subjected to IPC (four cycles of 5 min of ischemia and reperfusion) and then to 30 min of renal ischemia either 15 min (acute IPC) or 24 h (delayed IPC) later. Both acute and delayed renal IPC provided powerful protection against renal IR injury. Inhibition of Akt but not extracellular signal-regulated kinase phosphorylation prevented the protection that was afforded by acute IPC. Neither extracellular signal-regulated kinase nor Akt inhibition prevented protection that was afforded by delayed renal IPC. Pretreatment with an antioxidant, N-(2-mercaptopropionyl)-glycine, to scavenge free radicals prevented the protection that was provided by acute but not delayed renal IPC. Inhibition of protein kinase C or pertussis toxin-sensitive G-proteins attenuated protection from both acute and delayed renal IPC. Delayed renal IPC increased inducible nitric oxide synthase (iNOS) as well as heat-shock protein 27 synthesis, and the renal protective effects of delayed preconditioning were attenuated by a selective inhibitor of iNOS (l-N(6)[1-iminoethyl]lysine). Moreover, delayed IPC was not observed in iNOS knockout mice. Both acute and delayed IPC were independent of A(1) adenosine receptors (AR) as a selective A(1)AR antagonist failed to block preconditioning and acute and delayed preconditioning occurred in mice that lacked A(1)AR. Therefore, this study demonstrated that acute or delayed IPC provides renal protection against IR injury in mice but involves distinct signaling pathways.

A1adenosine receptor knockout mice are protected against acute radiocontrast nephropathy in vivo

The role of renal A1adenosine receptors (A1AR) in the pathogenesis of radiocontrast nephropathy is controversial. We aimed to further elucidate the role of A1AR in the pathogenesis of radiocontrast nephropathy and determine whether renal proximal tubule A1AR contribute to the radiocontrast nephropathy. To induce radiocontrast nephropathy, A1AR wild-type (WT) or knockout (KO) mice were injected with a nonionic radiocontrast (iohexol, 1.5–3 g iodine/kg). Some A1WT mice were pretreated with 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; a selective A1AR antagonist) before iohexol injection. A1AR contribute to the pathogenesis of radiocontrast nephropathy in vivo as the A1WT mice developed significantly worse acute renal failure, more renal cortex vacuolization, and had lower survival 24 h after iohexol treatment compared with the A1KO mice. DPCPX pretreatment also protected the A1WT mice against radiocontrast-induced acute renal failure. No differences in renal cortical apoptosis or inflammation were observed between A1WT and A1KO mice. To determine whether the proximal tubular A1AR mediate the direct renal cytotoxicity of radiocontrast, we treated proximal tubules in culture with iohexol with or without 2-chloro- N6-cyclopentyladenosine (a selective A1AR agonist) or DPCPX pretreatment. We also subjected cultured proximal tubule cells overexpressing A1AR or lacking A1AR to radiocontrast injury. Iohexol caused a direct dose-dependent reduction in proximal tubule cell viability as well as proliferation. Neither the A1AR agonist nor the antagonist treatment affected proximal tubule viability or proliferation. Moreover, overexpression or lack of A1AR failed to impact the iohexol toxicity on proximal tubule cells. Therefore, we conclude that radiocontrast causes acute renal failure via mechanisms dependent on A1AR; however, renal proximal tubule A1AR do not contribute to the direct tubular toxicity of radiocontrast.

A3 adenosine receptor activation decreases mortality and renal and hepatic injury in murine septic peritonitis

The role of A3 adenosine receptors (ARs) in sepsis and inflammation is controversial. In this study, we determined the effects of A3AR modulation on mortality and hepatic and renal dysfunction in a murine model of sepsis. To induce sepsis, congenic A3AR knockout mice (A3AR KO) and wild-type control (A3AR WT) mice were subjected to cecal ligation and double puncture (CLP). A3AR KO mice had significantly worse 7-day survival compared with A3AR WT mice. A3AR KO mice also demonstrated significantly higher elevations in plasma creatinine, alanine aminotransferase, aspartate aminotransferase, keratinocyte-derived chemokine, and TNF-alpha 24 h after induction of sepsis compared with A3AR WT mice. Renal cortices from septic A3AR KO mice exhibited increased mRNA encoding proinflammatory cytokines and enhanced nuclear translocation of NF-kB compared with samples from A3AR WT mice. A3AR WT mice treated with N6-(3-iodobenzyl)ADO-5'N-methyluronamide (IB-MECA; a selective A3AR agonist) or 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS-1191; a selective A3AR antagonist) had improved or worsened 7-day survival after induction of sepsis, respectively. Moreover, A3AR WT mice treated with IB-MECA or MRS-1191 showed acutely improved or worsened, respectively, renal and hepatic function following CLP. IB-MECA significantly reduced mortality in mice lacking the A1AR or A2aAR but not the A3AR, demonstrating specificity of IB-MECA in activating A3ARs and mediating protection against sepsis-induced mortality. We conclude that endogenous or exogenous A3AR activation confers significant protection from murine septic peritonitis primarily by attenuating the hyperacute inflammatory response in sepsis.