The Inhibitory Effects of Thiopental, Midazolam, and Ketamine on Human Neutrophil Functions

Anesthesia and cancer recurrence: a narrative review

Cancer is a leading cause of death worldwide. With the increasingly aging population, the number of emerging cancer cases is expected to increase markedly in the foreseeable future. Surgical resection with adjuvant therapy is the best available option for the potential cure of many solid tumors; thus, approximately 80% of patients with cancer undergo at least one surgical procedure during their disease. Agents used in general anesthesia can modulate cytokine release, transcription factors, and/or oncogenes. This can affect host immunity and the capability of cancer cells to survive and migrate, not only during surgery but for up to several weeks after surgery. However, it remains unknown whether exposure to anesthetic agents affects cancer recurrence or metastasis. This review explores the current literature to explain whether and how the choice of anesthetic and perioperative medication affect cancer surgery outcomes.

Autophagy impairment is involved in midazolam-induced lipid droplet accumulation and consequent phagocytosis decrease in BV2 cells

An increasing number of experimental and clinical observation suggest that the use of anaesthetics is closely associated with postoperative central nervous system (CNS) complications, such as delirium and cognitive dysfunction. Brain energy rescue is an emerging therapeutic strategy for central nervous system disease (CNSDs). However, the effect of anaesthetics on nerve cell energy utilisation, especially microglia, and its potential effects on cell function still unclear. Elucidating the effects of anaesthetics on lipid droplets, which are specific lipid storage organs, and phagocytosis of microglia is crucial to discover a new therapeutic concept for postoperative CNS complications. Here, we studied the effects of the commonly used anaesthetic midazolam on lipid droplets and phagocytosis in immortalised microglial BV2 cells. Lipid droplets were assessed by flow cytometry and triglyceride quantification. The phagocytosis of BV2 cells was evaluated by detecting their phagocytosis by latex beads. Additionally, the autophagy of BV2 cells was evaluated by western blot and observation under microscopy. Our results showed that midazolam caused lipid droplet accumulation and reduced phagocytosis in BV2 cells, and inhibition of lipid droplet accumulation partially restored phagocytosis. Furthermore, midazolam blocks autophagic degradation by increasing phosphorylated TFEB in BV2 cells, inhibition of midazolam-increased phosphorylated TFEB might contribute to the improvement of autophagic flux by rapamycin. Moreover, promoting autophagy reverse the lipid droplet accumulation and phagocytosis decrease. This study suggests autophagy is a target for attenuating lipid droplet accumulation, normal degradation of lipid droplets is important for maintaining microglia phagocytosis and attenuating the side effects of midazolam on the CNS.

Tumor Necrosis Factor Alpha: Implications of Anesthesia on Cancers

Cancer remains a major public health issue and a leading cause of death worldwide. Despite advancements in chemotherapy, radiation therapy, and immunotherapy, surgery is the mainstay of cancer treatment for solid tumors. However, tumor cells are known to disseminate into the vascular and lymphatic systems during surgical manipulation. Additionally, surgery-induced stress responses can produce an immunosuppressive environment that is favorable for cancer relapse. Up to 90% of cancer-related deaths are the result of metastatic disease after surgical resection. Emerging evidence shows that the interactions between tumor cells and the tumor microenvironment (TME) not only play decisive roles in tumor initiation, progression, and metastasis but also have profound effects on therapeutic efficacy. Tumor necrosis factor alpha (TNF-α), a pleiotropic cytokine contributing to both physiological and pathological processes, is one of the main mediators of inflammation-associated carcinogenesis in the TME. Because TNF-α signaling may modulate the course of cancer, it can be therapeutically targeted to ameliorate clinical outcomes. As the incidence of cancer continues to grow, approximately 80% of cancer patients require anesthesia during cancer care for diagnostic, therapeutic, or palliative procedures, and over 60% of cancer patients receive anesthesia for primary surgical resection. Numerous studies have demonstrated that perioperative management, including surgical manipulation, anesthetics/analgesics, and other supportive care, may alter the TME and cancer progression by affecting inflammatory or immune responses during cancer surgery, but the literature about the impact of anesthesia on the TNF-α production and cancer progression is limited. Therefore, this review summarizes the current knowledge of the implications of anesthesia on cancers from the insights of TNF-α release and provides future anesthetic strategies for improving oncological survival.

A mini-review of the effects of inhalational and intravenous anesthetics on oxidative stress in dogs

General anesthesia increases the production of reactive oxygen species (ROS), which can exacerbate or increase oxidative stress and thus affect the prognosis of surgical procedures. Oxidative stress has been implicated in the development of cardiovascular, dermatologic, oncologic, and other diseases in dogs, as well as ischemia and reperfusion injury. Some anesthetics, such as halogenated anesthetics, have been shown to stimulate the production of ROS, while others, such as propofol, have antioxidant properties. However, the antioxidant effects of these anesthetics may not be sufficient to counteract oxidative damage at the doses used clinically. Nevertheless, the effects of anesthetics should be considered to minimize oxidative damage during anesthesia in dogs to improve the outcome of procedures requiring general anesthesia. This mini-review addresses the current knowledge on oxidative stress during inhalational and intravenous anesthesia in dogs. There is still a lack of information on the management of anesthesia in dogs with respect to oxidative stress. Further research, including comprehensive clinical studies is needed to better understand oxidative injury mechanisms and improve perioperative protocols during anesthesia in dogs.

Anesthesia and cancer recurrence: an overview

Several perioperative factors are responsible for the dysregulation or suppression of the immune system with a possible impact on cancer cell growth and the development of new metastasis. These factors have the potential to directly suppress the immune system and activate hypothalamic-pituitary-adrenal axis and the sympathetic nervous system with a consequent further immunosuppressive effect.Anesthetics and analgesics used during the perioperative period may modulate the innate and adaptive immune system, inflammatory system, and angiogenesis, with a possible impact on cancer recurrence and long-term outcome. Even if the current data are controversial and contrasting, it is crucial to increase awareness about this topic among healthcare professionals for a future better and conscious choice of anesthetic techniques.In this article, we aimed to provide an overview regarding the relationship between anesthesia and cancer recurrence. We reviewed the effects of surgery, perioperative factors, and anesthetic agents on tumor cell survival and tumor recurrence.

Thiopental sodium loaded solid lipid nano-particles attenuates obesity-induced cardiac dysfunction and cardiac hypertrophy via inactivation of inflammatory pathway

This work evaluates solid lipid nanoparticles of thiopental sodium against obesity-induced cardiac dysfunction and hypertrophy and explores the possible mechanism of action. TS loaded SLNs were formulated by hot-homogenization and solvent diffusion method. TS-SLNs were scrutinized for entrapment efficiency, drug loading capacity, gastric stability, particle size, in vitro drug release. Mice were feed with the normal chow or high-fat diet for 08 weeks to induce obesity and primary cardiomyocytes. The therapeutic effects of thiopental sodium in the high fat diet (HFD) induced cardiac hypertrophy. Systolic blood pressure (SBP) was estimated at a regular time interval. At the end of the experimental study, systolic pressure left ventricular, LV end-diastolic pressure and rate of increase of LV pressure and antioxidant, apoptosis, cytokines and inflammatory scrutinized. HFD induced group mice exhibited a reduction in the body weight and enhancement of cardiac hypertrophy marker and dose-dependent treatment of thiopental sodium up-regulation the body weight and down-regulated the cardiac hypertrophy. Thiopental sodium significantly (p < .001) dose-dependently altered the antioxidant, biochemical, cardiac parameters and remodeling. Thiopental sodium significantly (p < .001) dose-dependently reduced the SBP. Thiopental sodium altered the apoptosis marker, pro-inflammatory cytokines, inflammatory parameters along with reduced the p38-MAPK level. The cardiac protective effect of thiopental sodium shed light on future therapeutic interventions in obesity and related cardiovascular complications via inflammatory pathway.

Oxidative stress under general intravenous and inhalation anaesthesia

Oxidative stress occurs when reactive oxygen species (ROS) production overwhelms cell protection by antioxidants. This review is focused on general anaesthesia-induced oxidative stress because it increases the rate of complications and delays recovery after surgery. It is important to know what effects of anaesthetics to expect in terms of oxidative stress, particularly in surgical procedures with high ROS production, because their either additive or antagonistic effect may be pivotal for the outcome of surgery. In vitro and animal studies on this topic are numerous but show large variability. There are not many human studies and what we know has been learned from different surgical procedures measuring different endpoints in blood samples taken mostly before and after surgery. In these studies most intravenous anaesthetics have antioxidative properties, while volatile anaesthetics temporarily increase oxidative stress in longer surgical procedures.

Impact of perioperative pain management on cancer recurrence: an ASRA/ESRA special article

Cancer causes considerable suffering and 80% of advanced cancer patients experience moderate to severe pain. Surgical tumor excision remains a cornerstone of primary cancer treatment, but is also recognized as one of the greatest risk factors for metastatic spread. The perioperative period, characterized by the surgical stress response, pharmacologic-induced angiogenesis, and immunomodulation results in a physiologic environment that supports tumor spread and distant reimplantation.In the perioperative period, anesthesiologists may have a brief and uniquewindow of opportunity to modulate the unwanted consequences of the stressresponse on the immune system and minimize residual disease. This reviewdiscusses the current research on analgesic therapies and their impact ondisease progression, followed by an evidence-based evaluation of perioperativepain interventions and medications.

Intraoperative immunomodulatory effects of sevoflurane versus total intravenous anesthesia with propofol in bariatric surgery (the OBESITA trial): study protocol for a randomized controlled pilot trial

Background

Obesity is associated with a chronic systemic inflammatory process. Volatile or intravenous anesthetic agents may modulate immune function, and may do so differentially in obesity. However, no study has evaluated whether these potential immunomodulatory effects differ according to type of anesthesia in obese patients undergoing laparoscopic bariatric surgery.

Methods/design

The OBESITA trial is a prospective, nonblinded, single-center, randomized, controlled clinical pilot trial. The trial will include 48 patients with a body mass index ≥ 35 kg/m², scheduled for laparoscopic bariatric surgery using sleeve or a Roux-en-Y gastric bypass technique, who will be allocated 1:1 to undergo general inhalational anesthesia with sevoflurane or total intravenous anesthesia (TIVA) with propofol. The primary endpoint is the difference in plasma interleukin (IL)-6 levels when comparing the two anesthetic agents. Blood samples will be collected prior to anesthesia induction (baseline), immediately after anesthetic induction, and before endotracheal extubation. Levels of other proinflammatory and anti-inflammatory cytokines, neutrophil chemotaxis, macrophage differentiation, phagocytosis, and occurrence of intraoperative and postoperative complications will also be evaluated.

Discussion

To our knowledge, this is the first randomized clinical trial designed to compare the effects of two different anesthetics on immunomodulation in obese patients undergoing laparoscopic bariatric surgery. Our hypothesis is that anesthesia with sevoflurane will result in a weaker proinflammatory response compared to anesthesia with propofol, with lower circulating levels of IL-6 and other proinflammatory mediators, and increased macrophage differentiation into the M2 phenotype in adipose tissue.

Trial registration

Registro Brasileiro de Ensaios Clínicos, RBR-77kfj5. Registered on 25 July 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3399-z) contains supplementary material, which is available to authorized users.

Propofol specifically reduces PMA-induced neutrophil extracellular trap formation through inhibition of p-ERK and HOCl

Neutrophil extracellular traps (NETs) are net-like chromatin fibers that can trap and kill microorganisms. Although several anti-inflammatory effects of intravenous anesthetics have been reported, it has not been investigated whether intravenous anesthetics influence NET formation.

AIMS

To compare the effects of four intravenous anesthetics (propofol, thiamylal sodium, midazolam, and ketamine) on phorbol myristate acetate (PMA)-induced NET formation and analyze the associated signaling pathways.

MATERIALS AND METHODS

PMA-stimulated NETs formed in the absence or presence of intravenous anesthetics were stained with SYTOX Green and then quantified. Inhibitors were applied to investigate the related mechanism, which was confirmed by western blotting, and ROS were detected.

KEY FINDINGS

The neutrophils incubated with propofol showed the lowest degree of NET formation compared with those incubated with the other intravenous anesthetics. Propofol significantly reduced the level of myeloperoxidase (MPO)-derived HOCl but not that of superoxide. Aminopyrine, an MPO inhibitor, markedly decreased the number of PMA-induced NETs, indicating the involvement of HOCl in the inhibitory effect of propofol on NET formation. According to western blotting results, the level of p-ERK was reduced by propofol during PMA-induced NET formation. The ERK inhibitor PD98059 decreased NET formation but did not inhibit PMA-induced HOCl generation, and aminopyrine did not reduce ERK phosphorylation.

SIGNIFICANCE

Through this study, we define a new anti-inflammatory effect of intravenous anesthetics. Of the four intravenous anesthetics tested, propofol was the most potent inhibitor of NET formation. Moreover, propofol resulted in a decrease in PMA-induced NET formation by two independent mechanisms: inhibition of HOCl and p-ERK.

Propofol specifically suppresses IL-1β secretion but increases bacterial survival in Staphylococcus aureus-infected RAW264.7 cells

Anesthetics have immunomodulatory effects, but the use of different assay systems has contributed to inconsistent results in the literature. IL-1β and reactive oxygen species (ROS) secreted by phagocytes are important factors that protect against Staphylococcus aureus infection. In this study, the effects of four intravenous anesthetics (propofol, thiamylal sodium, midazolam, and ketamine) on IL-1β secretion, ROS, and bacterial survival in S. aureus-infected RAW264.7 cells were evaluated. S. aureus-infected RAW264.7 cells with or without intravenous anesthetic treatment were established as the experimental model. Cell supernatants were subjected to ELISAs to measure secreted IL-1β. Cell pellets were subjected to qPCR and western blot analyses to analyze IL-1β mRNA and protein levels. Luminol chemiluminescence assays were used to detect ROS, and bacterial survival was determined by counting the colony forming units at the beginning and end of the infection. Compared with the levels after treatment with the other intravenous anesthetics, secreted IL-1β levels were lowest in the supernatant of S. aureus-infected RAW264.7 cell cultures after propofol treatment, but propofol did not decrease IL-1β mRNA or protein expression. However, thiamylal sodium and midazolam decreased IL-1β mRNA and protein expression in a dose-dependent manner. Additionally, propofol substantially decreased S. aureus-stimulated ROS and phagocytosis. Bacterial survival was strongly increased by propofol treatment. Of the four intravenous anesthetics, propofol was the most potent inhibitor of IL-1β secretion and ROS level in S. aureus-infected RAW264.7 cells; moreover, propofol resulted in an increase in bacterial survival by inhibiting ROS and phagocytosis.

Effects of surgery and anesthetic choice on immunosuppression and cancer recurrence

Background

The relationship between surgery and anesthetic-induced immunosuppression and cancer recurrence remains unresolved. Surgery and anesthesia stimulate the hypothalamic–pituitary–adrenal (HPA) axis and sympathetic nervous system (SNS) to cause immunosuppression through several tumor-derived soluble factors. The potential impact of surgery and anesthesia on cancer recurrence was reviewed to provide guidance for cancer surgical treatment.

Methods

PubMed was searched up to December 31, 2016 using search terms such as, “anesthetic technique and cancer recurrence,” “regional anesthesia and cancer recurrence,” “local anesthesia and cancer recurrence,” “anesthetic technique and immunosuppression,” and “anesthetic technique and oncologic surgery.”

Results

Surgery-induced stress responses and surgical manipulation enhance tumor metastasis via release of angiogenic factors and suppression of natural killer (NK) cells and cell-mediated immunity. Intravenous agents such as ketamine and thiopental suppress NK cell activity, whereas propofol does not. Ketamine induces T-lymphocyte apoptosis but midazolam does not affect cytotoxic T-lymphocytes. Volatile anesthetics suppress NK cell activity, induce T-lymphocyte apoptosis, and enhance angiogenesis through hypoxia inducible factor-1α (HIF-1α) activity. Opioids suppress NK cell activity and increase regulatory T cells.

Conclusion

Local anesthetics such as lidocaine increase NK cell activity. Anesthetics such as propofol and locoregional anesthesia, which decrease surgery-induced neuroendocrine responses through HPA-axis and SNS suppression, may cause less immunosuppression and recurrence of certain types of cancer compared to volatile anesthetics and opioids.

Anti-inflammatory properties of anesthetic agents

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2017. Other selected articles can be found online at http://ccforum.com/series/annualupdate2017. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Effect of Ketamine on Cocaine-Induced Immunotoxicity in Rats

The abuse of cocaine (COC) with ketamine (KET) is currently popular among young drug abusers and has been associated with increased risk of human immunodeficiency virus (HIV) infection. The effect of subacute exposure to COC and KET alone and in combination on the immune system was assessed in adult male Sprague-Dawley (SD) rats. To simulate the route and mode of human exposure, rats were treated with COC alone (5 mg/kg, IV), KET alone (100 mg/kg, PO) or KET followed immediately by COC (same doses and routes of administration) once-a-day for 7 consecutive days. Rats were sacrified 30 minutes following the last treatment. Total circulating leukocyte and lymphocyte counts were decreased with relative neutrophilia, whereas immunoglobulin M (Ig M) antibody response to sheep erythrocytes (SRBCs) was increased in animals treated with COC. Moreover, treatment with COC alone increased serum interleukin-10 (IL-10) concentration; however, it did not affect serum interferon gamma (INF-γ) concentration. Spleen histology showed hyperplasia of white pulp whereas thymus gland demonstrated mild cortical degeneration. On the other hand, KET treatment did not produce any significant change of any of these parameters. However, when coadministered with COC, significant reduction of bodyweight, spleen/bodyweight, and thymus/bodyweight ratios with degeneration of splenic white pulp and thymic cortex occurred. Moreover, the primary immunoglobulin response to SRBC and serum IL-10 concentration were decreased without significant change in serum IFN-γ or circulating leukocytic counts. COC caused a significant increase in serum corticosterone concentration that KET effectively prevented. On the other hand, a significant increase in plasma and tissue concentrations of norcocaine (NC) resulted following KET and COC administration in combination. Daily SKF-525A pretreatment at a dose of 30 mg/kg, IP, for 7 days 1 hour prior to KET and COC in combination effectively reversed the effects of this combination on body weight, organ/bodyweight ratios, histopathology, and serum Ig M and IL-10 concentrations without affecting leukocytic counts. On the other hand, SKF-525A pretreatment did not change the immunomodulatory effects of COC compared to non-pretreated animals. The results suggest that COC-induced immunomodulation most likely occurred through neuroendocrinal mechanisms. On the other hand, enhanced oxidative metabolism of COC in the presence of KET-induced immunosuppression.

The Relationship Between Sedatives, Sedative Strategy, and Healthcare-Associated Infection: A Systematic Review

BACKGROUND Healthcare-associated infections (HAIs) cause significant morbidity in critically ill patients. An underappreciated but potentially modifiable risk factor for infection is sedation strategy. Recent trials suggest that choice of sedative agent, depth of sedation, and sedative management can influence HAI risk in mechanically ventilated patients. OBJECTIVE To better characterize the relationships between sedation strategies and infection. METHODS Systematic literature review. RESULTS We found 500 articles and accepted 70 for review. The 3 most common sedatives for mechanically ventilated patients (benzodiazepines, propofol, and dexmedetomidine) have different pharmacologic and immunomodulatory effects that may impact infection risk. Clinical data are limited but retrospective observational series have found associations between sedative use and pneumonia whereas prospective studies of sedative interruptions have reported possible decreases in bloodstream infections, pneumonia, and ventilator-associated events. CONCLUSION Infection rates appear to be highest with benzodiazepines, intermediate with propofol, and lowest with dexmedetomidine. More data are needed but studies thus far suggest that a better understanding of sedation practices and infection risk may help hospital epidemiologists and critical care practitioners find new ways to mitigate infection risk in critically ill patients. Infect Control Hosp Epidemiol 2016;1-9.

Anesthesia, microcirculation, and wound repair in aging

Age-related changes in skin contribute to impaired wound healing after surgical procedures. Changes in skin with age include decline in thickness and composition, a decrease in the number of most cell types, and diminished microcirculation. The microcirculation provides tissue perfusion, fluid homeostasis, and delivery of oxygen and other nutrients. It also controls temperature and the inflammatory response. Surgical incisions cause further disruption of the microvasculature of aged skin. Perioperative management can be modified to minimize insults to aged tissues. Judicious use of fluids, maintenance of normal body temperature, pain control, and increased tissue oxygen tension are examples of adjustable variables that support the microcirculation. Anesthetic agents influence the microcirculation of a combination of effects on cardiac output, arterial pressure, and local microvascular changes. The authors examined the role of anesthetic management in optimizing the microcirculation and potentially improving postoperative wound repair in older persons.

Measuring neutrophil speed and directionality during chemotaxis, directly from a droplet of whole blood

Neutrophil chemotaxis is critical for defense against infections and its alterations could lead to chronic inflammation and tissue injury. The central role that transient alterations of neutrophil chemotaxis could have on patient outcomes calls for its quantification in the clinic. However, current methods for measuring neutrophil chemotaxis require large volumes of blood and are time consuming. To address the need for rapid and robust assays, we designed a microfluidic device that measures neutrophil chemotaxis directly from a single droplet of blood. We validated the assay by comparing neutrophil chemotaxis from finger prick, venous blood and purified neutrophil samples. We found consistent average velocity of (19 ± 6 μm/min) and directionality (91.1%) between the three sources. We quantified the variability in neutrophil chemotaxis between healthy donors and found no significant changes over time. We also validated the device in the clinic and documented temporary chemotaxis deficiencies after burn injuries.

Midazolam induces cellular apoptosis in human cancer cells and inhibits tumor growth in xenograft mice

Midazolam is a widely used anesthetic of the benzodiazepine class that has shown cytotoxicity and apoptosisinducing activity in neuronal cells and lymphocytes. This study aims to evaluate the effect of midazolam on growth of K562 human leukemia cells and HT29 colon cancer cells. The in vivo effect of midazolam was investigated in BALB/c-nu mice bearing K562 and HT29 cells human tumor xenografts. The results show that midazolam decreased the viability of K562 and HT29 cells by inducing apoptosis and S phase cell-cycle arrest in a concentration-dependent manner. Midazolam activated caspase-9, capspase-3 and PARP indicating induction of the mitochondrial intrinsic pathway of apoptosis. Midazolam lowered mitochondrial membrane potential and increased apoptotic DNA fragmentation. Midazolam showed reactive oxygen species (ROS) scavenging activity through inhibition of NADPH oxidase 2 (Nox2) enzyme activity in K562 cells. Midazolam caused inhibition of pERK1/2 signaling which led to inhibition of the anti-apoptotic proteins Bcl-XL and XIAP and phosphorylation activation of the pro-apoptotic protein Bid. Midazolam inhibited growth of HT29 tumors in xenograft mice. Collectively our results demonstrate that midazolam caused growth inhibition of cancer cells via activation of the mitochondrial intrinsic pathway of apoptosis and inhibited HT29 tumor growth in xenograft mice. The mechanism underlying these effects of midazolam might be suppression of ROS production leading to modulation of apoptosis and growth regulatory proteins. These findings present possible clinical implications of midazolam as an anesthetic to relieve pain during in vivo anticancer drug delivery and to enhance anticancer efficacy through its ROS-scavenging and pro-apoptotic properties.

Sedation and analgesia in mechanically ventilated preterm neonates: continue standard of care or experiment?

Attention to comfort and pain control are essential components of neonatal intensive care. Preterm neonates are uniquely susceptible to pain and agitation, and these exposures have a negative impact on brain development. In preterm neonates, chronic pain and agitation are common adverse effects of mechanical ventilation, and opiates or benzodiazepines are the pharmacologic agents most often used for treatment. Questions remain regarding the efficacy, safety, and neurodevelopmental impact of these therapies. Both preclinical and clinical data suggest troubling adverse drug reactions and the potential for adverse longterm neurodevelopmental impact. The negative impacts of standard pharmacologic agents suggest that alternative agents should be investigated. Dexmedetomidine is a promising alternative therapy that requires further interprofessional and multidisciplinary research in this population.

Neuroprotective effects of propofol, thiopental, etomidate, and midazolam in fetal rat brain in ischemia-reperfusion model

PURPOSE

The aim of this study was to investigate the neuroprotective effects of propofol, thiopental, etomidate, and midazolam as anesthetic drugs in fetal rat brain in the ischemia-reperfusion (IR) model.

METHODS

Pregnant rats of day 19 were randomly allocated into eight groups. Fetal brain ischemia was induced by clamping the utero-ovarian artery bilaterally for 30 min and reperfusion was achieved by removing the clamps for 60 min. In the control group, fetal rat brains were obtained immediately after laparotomy. In the sham group, fetal rat brains were obtained 90 min after laparotomy. In the IR group, IR procedure was performed. No treatment was given in the IR group. One milliliter intralipid solution, 40 mg/kg propofol, 3 mg/kg thiopental, 0.1 mg/kg etomidate, and 3 mg/kg midazolam was administered intraperitoneally in the vehicle group, propofol group, thiopental group, etomidate group, and midazolam group, respectively, 20 min before IR procedure. At the end of the reperfusion period, the whole brains of the fetal rats were removed for evaluation of thiobarbituric acid reactive substances and for examination by electron microscopy.

RESULTS

According to lipid peroxidation data, all the anesthetic drugs provide neuroprotection; however, ultrastructural findings and mitochondrial scoring confirms that only propofol and midazolam provides a strong neuroprotective effect.

CONCLUSIONS

Propofol and midazolam may be used to protect fetal brain in case of acute fetal distress and hypoxic injury as a first choice anesthetic drug in cesarean delivery.

Xenon anesthesia reduces TNFα and IL10 in bariatric patients

BACKGROUND

Anesthesia is able to modulate the balance between proinflammatory and anti-inflammatory cytokine production during surgery. The aim of this study is to assess the effect of three anesthesia approaches, total intravenous anesthesia (TIVA), inhalation anesthesia, and xenon anesthesia, on sieric levels of nitric oxide (NO), IL6, IL10, and TNFα in obese patients undergoing Roux-en-Y laparoscopic gastric bypass.

METHODS

Thirty adult morbidly obese patients (BMI > 35) scheduled for Roux-en-Y laparoscopic gastric bypass were randomly recruited and allocated to TIVA (N = 10), inhalation anesthesia (SEV, N = 10), and xenon anesthesia (XE, N = 10). Exclusion criteria were ASA IV, age <18 or >60 years, and Mallampati IV. Opioid dosage and ventilation parameters were standardized. Sieric levels of NO, IL6, IL10, and TNFα were assessed at T0 (before induction of anesthesia), T1 (end of surgery), and T2 (12 h after the end of surgery). We compared the relative cytokine level variations (delta) at T1 and T2 and the cytokine exposure levels calculated as the area under the curve (AUC) between T0 and T2 in the XE and non-XE (SEV + TIVA) groups.

RESULTS

At T1, we found a significant ΔIL10 (reduction) and ΔTNFα (reduction) between XE and SEV (p < 0.05) and XE and TIVA (p < 0.05) groups. At T2, ΔIL10 was still significant. Furthermore, we found a reduced AUC value for TNFα in the XE group.

CONCLUSIONS

Xenon anesthesia seems able to inhibit postoperative proinflammatory cytokine imbalance in morbidly obese patients undergoing Roux-en-Y laparoscopic gastric bypass; the reduced ΔTNFα at T1 and the reduced global exposition to TNFα in the XE group may explain the reduced ΔIL10 at T1 and T2.

Sedative drug modulates T-cell and lymphocyte function-associated antigen-1 function

BACKGROUND

Sedative drugs modify immune cell functions via several mechanisms. However, the effects of sedatives on immune function have been primarily investigated in neutrophils and macrophages, and to the lesser extent lymphocytes. Lymphocyte function-associated antigen-1 (LFA-1) is an adhesion molecule that has a central role in regulating immune function of lymphocytes including interleukin-2 (IL-2) production and lymphocyte proliferation. Previous clinical studies reported that propofol and isoflurane reduced IL-2 level in patients, but midazolam did not. We previously demonstrated that isoflurane inhibited LFA-1 binding to its counter ligand, intercellular adhesion molecule-1 (ICAM-1), which might contribute to the reduction of IL-2 levels. In the current study, we examined the effect of propofol, midazolam, and dexmedetomidine on LFA-1/ICAM-1 binding, and the subsequent biological effects.

METHODS

The effect of sedative drugs on T-cell proliferation and IL-2 production was measured by calorimetric assays on human peripheral blood mononuclear cells. Because LFA-1/ICAM-1 binding has an important role in T-cell proliferation and IL-2 production, we measured the effect of sedative drugs on ICAM-1 binding to LFA-1 protein (cell-free assay). This analysis was followed by flow cytometric analysis of LFA-1 expressing T-cell binding to ICAM-1 (cell-based assay). To determine whether the drug/LFA-1 interaction is caused by competitive or allosteric inhibition, we analyzed the sedative drug effect on wild-type and high-affinity LFA-1 and a panel of monoclonal antibodies that bind to different regions of LFA-1.

RESULTS

Propofol at 10 to 100 μM inhibited ICAM-1 binding to LFA-1 in cell-free assays and cell-based assays (P < 0.05). However, dexmedetomidine and midazolam did not affect LFA-1/ICAM-1 binding. Propofol directly inhibits LFA-1 binding to ICAM-1 by binding near the ICAM-1 contact area in a competitive manner. At clinically relevant concentrations, propofol, but not dexmedetomidine or midazolam, inhibited IL-2 production (P < 0.05). Additionally, propofol inhibited lymphocyte proliferation (P < 0.05).

CONCLUSIONS

Our study suggests that propofol competitively inhibits LFA-1 binding to ICAM-1 on T-cells and suppresses T-cell proliferation and IL-2 production, whereas dexmedetomidine and midazolam do not significantly influence these immunological assays.

The effect of ketamine anesthesia on the immune function of mice with postoperative septicemia

BACKGROUND

It is unknown how ketamine anesthesia immunologically affects the outcome of patients with postoperative septicemia. We investigated the effects of ketamine anesthesia on mice with an Escherichia coli or lipopolysaccharide (LPS) challenge after laparotomy, focusing on phagocytosis by liver macrophages (Kupffer cells) and cytokine production.

METHODS

C57BL/6 mice received ketamine or sevoflurane anesthesia during laparotomy, which was followed by an E. coli or LPS challenge; thereafter, mouse survival rates and cytokine secretions were examined. The effects of a β-adrenoceptor antagonist, nadolol, on ketamine anesthesia were also assessed to clarify the mechanisms of ketamine-induced immunosuppressive effects.

RESULTS

Ketamine anesthesia increased the mouse survival rate after LPS challenge after laparotomy compared with sevoflurane anesthesia, whereas such an effect of ketamine was not observed after E. coli challenge. Ketamine suppressed tumor necrosis factor (TNF) and interferon (IFN)-γ secretion after LPS and E. coli challenge. When bacterial growth was inhibited using an antibiotic, ketamine anesthesia effectively improved mouse survival after E. coli challenge compared with sevoflurane anesthesia. Neutralization of TNF also improved survival and decreased IFN-γ secretion after bacterial challenge in antibiotic-treated mice with sevoflurane anesthesia, suggesting that ketamine's suppression of TNF may improve survival. Ketamine also suppressed in vivo phagocytosis of microspheres by Kupffer cells in LPS-challenged mice. Concomitant use of nadolol with an anesthetic dose of ketamine did not restore TNF suppression in LPS-challenged mice, suggesting a mechanism independent of the β-adrenergic pathway. However, it restored TNF secretion under low-dose ketamine (10% anesthetic dose). In contrast, nadolol restored the decrease in phagocytosis by Kupffer cells, which was induced by the anesthetic dose of ketamine via the β-adrenergic pathway, suggesting distinct mechanisms.

CONCLUSION

Ketamine suppresses TNF production and phagocytosis by Kupffer cells/macrophages. Therefore, unless bacterial growth is well controlled (by an antibiotic), postoperative infection might not improve despite reduction of the inflammatory response.

Adverse drug events associated with the use of analgesics, sedatives, and antipsychotics in the intensive care unit

As critically ill patients frequently receive analgesics, sedatives, and antipsychotics to optimize patient comfort and facilitate mechanical ventilation, adverse events associated with the use of these agents can affect all organ systems and result in substantial morbidity and mortality. Although many of these adverse effects are common pharmacologic manifestations of the agent, and therefore frequently reversible, others are idiosyncratic and thus unexpected. The critically ill are more susceptible to adverse drug events than nonintensive care unit patients due to the high doses and long periods for which each of these agents are often administered, the frequent use of intravenous formulations that contain adjuvants that may lead to toxicity in some instances, and the high prevalence of end-organ dysfunction that affects the pharmacokinetic and pharmacodynamic response to therapy. This paper will review the most common and serious adverse drug events reported to occur with the use of sedatives, analgesics, and antipsychotics in the intensive care unit; highlight the pharmacokinetic, pharmacodynamic, and pharmacogenetic factors that can influence analgesic, sedative, and antipsychotic response and safety in the critically ill; and identify strategies that can be used to minimize toxicity with these agents.

Thiopental improves renal ischemia-reperfusion injury

Ischemia/reperfusion (I/R) occurs in a number of pathological conditions, including myocardial infarction, stroke, aortic surgery, cardiopulmonary bypass surgery, organ transplantation, resuscitation, and critical care. Massive and abrupt release of oxygen-free radicals after reperfusion triggers oxidative damage. Before critical operations or after resuscitation, it would be wise to find a suitable prophylactic treatment to avoid I/R damage. We aimed to determine whether several commonly used intravenous anesthetics protect against renal I/R injury.

METHODS

Animals were randomly divided into seven groups, each consisting of six animals: sham group, control group, thiopental group, propofol group, intralipid group, etomidate group, and ketamine group. At the end of the 60-min ischemic period, 60 min reperfusion was established and the materials administered 15 min before the reperfusion. At the end of the reperfusion period, the samples of blood and tissue were reaped for biochemical and serological evaluation.

RESULTS

I/R procedure significantly increased malondialdehyde (MDA) levels, decreased catalase (CAT) activities, and superoxide dismutase (SOD) levels. The lowest MDA mean level was in the thiopental group and the highest MDA mean level was in control group. The lowest CAT mean level was in the intralipid group and the highest CAT mean level was in the etomidate group. The lowest SOD mean level was in the control group and the highest SOD mean level was in the propofol group.

CONCLUSION

Thiopental and propofol, especially thiopental, are more effective to protect renal I/R injury.

Ketamine inhibits transcription factors activator protein 1 and nuclear factor-kappaB, interleukin-8 production, as well as CD11b and CD16 expression: studies in human leukocytes and leukocytic cell lines

BACKGROUND

Recent data indicate that ketamine exerts antiinflammatory actions. However, little is known about the signaling mechanisms involved in ketamine-induced immune modulation. In this study, we investigated the effects of ketamine on lipopolysaccharide-induced activation of transcription factors activator protein 1 (AP-1) and nuclear factor-kappaB (NF-kappaB) in human leukocyte-like cell lines and in human blood neutrophils.

METHODS

Electric mobility shift assays were used to investigate ketamine's effects on nuclear binding activity of both transcription factors in U937 cells, and a whole blood flow cytometric technique was used for AP-1 and NF-kappaB determination in leukocytes. Cell lines with different expression patterns of opioid and N-methyl-D-aspartate receptors were used for reverse transcription-polymerase chain reaction to investigate receptors involved in ketamine signaling. Ketamine's effect on interleukin-8 production was assessed in a whole blood assay.

RESULTS

Ketamine inhibited both transcription factors in a concentration-dependent manner. These effects did not depend on opiate or N-methyl-D-aspartate receptors. Ketamine also reduced interleukin-8 production in whole blood and expression of CD11b and CD16 on neutrophils.

CONCLUSION

The immunoinhibitory effects of ketamine are at least in part caused by inhibition of transcription factors NF-kappaB and AP-1, which regulate production of proinflammatory mediators. However, signaling mechanisms different from those present in the central nervous system are responsible for ketamine-mediated immunomodulation.

Persistency and pathway of isoflurane-induced inhibition of superoxide production by neutrophils

BACKGROUND

Our previous work has demonstrated that treatment with isoflurane has a preconditioning-like inhibitory effect on superoxide production (SOP) by polymorphonuclear neutrophils. The current objectives were to determine persistency of this effect and to clarify where in the signalling pathway this inhibition of SOP occurred. The latter was accomplished using two receptor-dependent neutrophil agonists, platelet activating factor (PAF) and formyl-methionyl-leucyl-phenylalanine (fMLP), and two receptor-independent neutrophil stimuli, the protein-kinase C stimulator, phorbol myristate acetate (PMA), and the calcium ionophore, A23187.

METHODS

Arterial blood samples were obtained from eight dogs under baseline condition (conscious state), during isoflurane (1 MAC) administration, and 24 and 48 hr post-isoflurane (also in conscious state). Neutrophils were isolated and stimulated with 1 muM concentrations of PAF, fMLP, PMA, and A23187. SOP was measured spectrophotometrically.

RESULTS

Isoflurane administration caused (1) an approximate 50% decrease in SOP during PAF or fMLP (P < 0.01 vs baseline), which remained evident from 24 to 48 hr following isoflurane; (2) an initial 29% decrease in SOP during PMA (P < 0.05 vs baseline), which returned to baseline by 24 hr following isoflurane; and (3) no change in SOP during A23187 (P > 0.05 vs baseline).

CONCLUSIONS

Isoflurane administration caused prolonged (from 24 to 48 hr) decreases in agonist-induced SOP by neutrophils. This effect involved inhibition at site(s) in the signalling pathway upstream from protein kinase C. The current findings suggest that the intraoperative use of isoflurane may result in an extended impairment to the antibacterial host defense mechanism and that neutrophil inhibition may play a role in the delayed tissue protection afforded by treatment with volatile anesthetics.

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.

Ketamine inhibits maturation of bone marrow-derived dendritic cells and priming of the Th1-type immune response

BACKGROUND

Dendritic cells (DCs) play a key role as antigen-presenting cells and growing evidence suggests that DCs influence T-cell activation and regulate the polarity of the immune response. Ketamine has been reported to have immunomodulatory properties that affect immune cells, including macrophages and natural killer cells. However, the effect of ketamine on DCs has not been characterized. We examined the immunomodulation of DCs by ketamine.

METHODS

We used bone marrow-derived DCs induced by granulocyte-monocyte-colony stimulating factor and interleukin (IL)-4 from bone marrow and analyzed the expression of costimulatory molecules (CD40, CD80, and CD86), major histocompatibility complex class II molecules, and secretion of IL-12p40. Furthermore, we evaluated the immune response in mixed cell cultures of DCs and T cells and the contact hypersensitivity response in a whole animal.

RESULTS

Ketamine suppressed the expression of CD40, CD80, and major histocompatibility complex class II molecules in DCs. DCs treated with ketamine also secreted less IL-12p40 and displayed greater endocytosis. In mixed cell cultures with CD4+ T cells and DCs, ketamine-treated DCs showed less propensity to stimulate the proliferation of CD4+ T cells and the secretion of interferon from CD4+ T cells. Furthermore, ketamine-treated DCs impaired the induction of a cell-mediated immune response.

CONCLUSION

Our findings suggest that ketamine inhibits the functional maturation of DCs and interferes with DC induction of Th1 immunity in the whole animal. These novel findings provide new insight into the immunopharmacological role of ketamine.

Comparison of systemic Listeria monocytogenes infection in esophageally inoculated mice anesthetized with isoflurane or pentobarbital

In previous attempts to produce a murine model of gastrointestinal listeriosis, the authors observed that pentobarbital anesthesia greatly increased disease severity in mice that were esophageally inoculated with the bacterium Listeria monocytogenes. In this study, they sought to evaluate the severity of systemic infection in inoculated mice that were anesthetized with isoflurane, an inhalational agent that is safer than pentobarbital and more commonly used for rodent anesthesia. Compared with pentobarbital anesthesia, isoflurane anesthesia resulted in infections of lesser severity, similar to those observed in unanesthetized mice. A pilot study in which mice were anesthetized with isoflurane for 5, 10 or 20 min suggested that this effect was not related to the duration of anesthesia. These results show that isoflurane anesthesia administered for 5 to 20 min does not potentiate the severity of listeriosis infection in mice esophageally inoculated with L. monocytogenes.

Changes in biomechanical parameters during heart perfusion and after midazolam pre-medication--experimental pilot study

BACKGROUND

Midazolam is a frequently used benzodiazepine in anaesthesiology and intensive care.

AIM

The aim of pilot study was to monitor its effect during heart perfusion in the laboratory rat.

METHODS

The same groups of animals (n = 10). The 1(st) group was treated with midazolam in a dose of 0.5mg/kg i.p. The 2(nd) group was a placebo. After i.p. administration of heparine injection of 500 IU dose, the hearts were excised and perfused (modified Langendorf's method). Working schedule: stabilization/ischaemia/reperfusion proceed at intervals of 20/30/60 min. Monitored parameters in isolated heart: left ventricle pressure (LVP), end-diastolic pressure (LVEDP), contractility (+dP/dt(max)).

RESULTS

The treated hearts showed improved postischemic recovery, reaching LVP values of 92 +/- 6 % at the end of the reperfusion, placebo only 61 +/- 7 %. In placebo hearts LVEDP rose from 10.0 +/- 0.5 mmHg to 43 +/- 4 mmHg after, in treated animals only about 25 mmHg. The treated hearts improved +dP/dt(max) recovery during reperfusion to 91 +/- 8 %. These values were significantly greater than those obtained from the placebo hearts.

CONCLUSIONS

Positive changes in monitored parameters were found in this experimental pilot study. We conclude that the administration of midazolam in laboratory rats has a cardioprotective potential against ischemia-reperfusion induced injury.

[Inflammation and acute brain injuries in intensive care]

Patients with acute brain injuries or susceptibility to post-surgery stroke are a major therapeutic challenge for intensive care and anaesthesiology medicine. The control of systemic stress involved in brain damage is necessary to reduce the frequency and severity of secondary brain lesions. Inflammation is known to be directly involved in acute brain lesions. The brain is a major participant in inflammation control through activation or inhibition effects. The exact mechanisms involved in deleterious effects following acute brain injuries due to inflammation are still unknown. This non-exhaustive study will expose the principal processes involved in inflammatory brain disease and explain the consequences of peripheral inflammation for the brain. Neuroprotection strategies in acute neuroinflammation will be reported with a focus on anaesthetic agents and the inflammation cascade.

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.

Propofol reduces nitric oxide-induced apoptosis in testicular ischemia-reperfusion injury by downregulating the expression of inducible nitric oxide synthase

BACKGROUND

The aim of the present study was to investigate the underlying mechanisms in the preventive effects of intravenous anesthetics on testicular ischemia-reperfusion injury.

METHODS

Forty male Wistar Albino rats were randomly assigned to four groups of 10 rats each. Anesthesia was induced and maintained with thiopental in groups 1 and 2 and with propofol in groups 3 and 4. Groups 2 and 4 received left testicular ischemia (torsion) for 1 h and reperfusion (detorsion) for 24 h. Groups 1 and 3 (control groups) had no testicular torsion and detorsion. At 24 h of reperfusion, animals were killed and ipsilateral testes were removed for determination of tissue nitric oxide (NO) levels and immunohistochemical evaluation of endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS), and apoptosis protease-activating factor 1 (APAF-1).

RESULTS

Between groups 1 and 3, there were no differences in tissue NO levels and eNOS, iNOS, and APAF-1 expressions. iNOS and APAF-1 expressions were markedly increased in group 2, but these parameters were at the mild to moderate level in group 4 at 24 h of reperfusion. Also, elevated expression of iNOS was accompanied by a high NO production in group 2 compared with group 4. Although eNOS expressions were increased in both the groups (groups 2 and 4), there were no significant differences between these groups.

CONCLUSIONS

Propofol as an anesthetic agent may attenuate germ cell-specific apoptosis and decrease NO biosynthases through downregulation of iNOS expression in an animal model of testicular torsion and detorsion.

The protective effects of intravenous anesthetics and verapamil in gut ischemia/reperfusion-induced liver injury

BACKGROUND

We investigated the protective effects of IV anesthetics and verapamil in gut ischemia/reperfusion-induced liver injury.

METHODS

Forty male Wistar Albino rats were randomly assigned to four groups of 10 rats each. Anesthesia was induced and maintained with propofol in Groups 1 and 3 and with thiopental in Groups 2 and 4 during the experiment. All animals developed intestinal ischemia after occlusion of the superior mesenteric artery for 30 min. Reperfusion was induced by removal of the microvascular clamp and was allowed to continue for 120 min. The animals in Groups 3 and 4 were given verapamil 10 min before reperfusion. Liver and ileum samples were taken for measurement of malondialdehyde (MDA) and histopathologic examination before ischemia and 30 and 120 min after reperfusion. Blood samples were also obtained for measurement of plasma tumor necrosis factor-alpha and interleukin-6 levels.

RESULTS

Gut ischemia/reperfusion-induced significant increases in MDA contents of liver and gut and serum cytokines, consistent with histopathologic injury scores. Propofol effectively stabilized the MDA levels and decreased the tissue injury scores of the liver and gut. Tumor necrosis factor-alpha and interleukin-6 levels increased less in the propofol groups than in the thiopental groups. There was no additive preventive effect of verapamil on propofol. The addition of verapamil to thiopental was effective in decreasing the serum cytokines and liver MDA content.

CONCLUSION

Propofol may offer advantages by inhibiting lipid peroxidation and inflammatory cytokine production in an animal model of gut ischemia/reperfusion-induced liver injury.

Benzodiazepines inhibit the rate of neutrophil apoptosis

BACKGROUND

Benzodiazepines, which are commonly administered perioperatively, can depress immune function. Neutrophil apoptosis plays a central role in the regulation of inflammation. This is particularly important during and after surgery.

AIM

To examine the effects of benzodiazepines (midazolam and diazepam) on neutrophil apoptosis.

METHODS

Venous blood samples were withdrawn from patients scheduled to undergo elective surgery, (a) immediately prior to, and 10 minutes after administration of midazolam 0.2 mg/kg intravenously (n=11) and (b) immediately prior to, and 60 minutes after administration of diazepam 10 mg p.o. (n=10). Neutrophil apoptosis was measured by Annexin V-FITC after 1 and 12 hours in culture.

RESULTS

The percentage of apoptotic cells was significantly less after midazolam at 12% (11.9) hours in culture compared to pre-midazolam 29.7% (13.3) (p<0.05). After diazepam, the rates of neutrophil apoptosis were also significantly less after 12 hours in culture (p<0.05).

CONCLUSION

Administration of benzodiazepines in clinically relevant doses inhibits neutrophil apoptosis. In the perioperative period, this may influence the inflammatory response to surgery.

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

PURPOSE

The aim of this review of the literature was to evaluate the effectiveness of anesthetics in protecting the heart against myocardial ischemia-reperfusion injury.

SOURCE

Articles were obtained from the Medline database (1980-, search terms included heart, myocardium, coronary, ischemia, reperfusion injury, infarction, stunning, halothane, enflurane, desflurane, isoflurane, sevoflurane, opioid, morphine, fentanyl, alfentanil sufentanil, pentazocine, buprenorphine, barbiturate, thiopental, ketamine, propofol, preconditioning, neutrophil adhesion, free radical, antioxidant and calcium).

PRINCIPAL FINDINGS

Protection by volatile anesthetics, morphine and propofol is relatively well investigated. It is generally agreed that these agents reduce the myocardial damage caused by ischemia and reperfusion. Other anesthetics which are often used in clinical practice, such as fentanyl, ketamine, barbiturates and benzodiazepines have been much less studied, and their potential as cardioprotectors is currently unknown. There are some proposed mechanisms for protection by anesthetic agents: ischemic preconditioning-like effect, interference in the neutrophil/platelet-endothelium interaction, blockade of Ca2+ overload to the cytosolic space and antioxidant-like effect. Different anesthetics appear to have different mechanisms by which protection is exerted. Clinical applicability of anesthetic agent-induced protection has yet to be explored.

CONCLUSION

There is increasing evidence of anesthetic agent-induced protection. At present, isoflurane, sevoflurane and morphine appear to be most promising as preconditioning-inducing agents. After the onset of ischemia, propofol could be selected to reduce ischemia-reperfusion injury. Future clinical application depends on the full elucidation of the underlying mechanisms and on clinical outcome trials.