Midazolam activates the intrinsic pathway of apoptosis independent of benzodiazepine and death receptor signaling

Role of midazolam on cancer progression/survival - An updated systematic review

Background and Aims

Cancer is a leading cause of mortality worldwide. Despite advancements in cancer management, cancer progression remains a challenge, requiring the development of novel therapies. Midazolam is a commonly used adjunct to anaesthesia care for various surgeries, including cancer. Recently, there has been a growing interest in exploring the potential role of midazolam as an anticancer agent; however, the exact mechanism of this linkage is yet to be investigated thoroughly.

Methods

Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, this systematic review presented aggregated evidence (till November 2022) of the effects of midazolam on cancer progression and survival. All primary research article types where midazolam was administered in vivo or in vitro on subjects with cancers were included. No restrictions were applied on routes of administration or the type of cancer under investigation. Narrative synthesis depicted qualitative findings, whereas frequencies and percentages presented numerical data.

Results

Of 1720 citations, 19 studies were included in this review. All articles were preclinical studies conducted either in vitro (58%, 11/19) or both in vivo and in vitro (42%, 8/19). The most studied cancer was lung carcinoma (21%, 4/19). There are two main findings in this review. First, midazolam delays cancer progression (89%, 17/19). Second, midazolam reduces cancer cell survival (63%, 12/19). The two major mechanisms of these properties can be explained via inducing apoptosis (63%, 12/19) and inhibiting cancer cell proliferation (53%, 10/19). In addition, midazolam demonstrated antimetastatic properties via inhibition of cancer invasion (21%, 4/19), migration (26%, 5/19), or epithelial-mesenchymal transition (5%, 1/19). These anticancer properties of midazolam were demonstrated through different pathways when midazolam was used alone or in combination with traditional cancer chemotherapeutic agents.

Conclusion

This systematic review highlights that midazolam has the potential to impede cancer progression and decrease cancer cell survival. Extrapolation of these results into human cancer necessitates further investigation.

Spinal versus general anesthesia: Comparing outcomes in pediatric patients undergoing urologic procedures

INTRODUCTION

Available literature comparing spinal anesthesia (SA) to general anesthesia (GA) in the pediatric population describes multiple benefits in appropriately selected patients including cost reduction, lower incidence of complications, and shorter operative times. In patients undergoing urologic procedures, data are sparse.

OBJECTIVE

Our goal was to expand on the paucity of existing urologic literature as SA appears to be uniquely suited for a substantial number of its common pediatric procedures.

METHODS

Within a single institution, patients who had a urologic procedure performed under SA between May 2019 and July 2021 and were less than 18 months old were compared with a matched cohort of patients who had GA. The SA and GA groups were compared by two-sample t-tests, chi-square test for independence, and Fisher's exact test.

RESULTS

There were a total of 184 SA and 202 GA patients. There was no significant difference in the demographics except that SA patients were younger and weighed less than GA patients. The patients in the SA group needed less opioids both during the surgery (0% vs 26.1% p N/A) and in the immediate postoperative period when compared with GA patients (0% vs 18.2% p N/A). The patients who had SA had fewer complications necessitating PICU admission, or cancellation of surgery (0% vs 6.8% p = 0.03). Total anesthesia and emergence time were lower for SA patients (41 vs 50.2 p = 0.001 & 3.4 vs 6.1 p = 0.001). Both surgery and total OR time were not different between the groups (37.6 vs 35.5 p = 0.35 and 56.3 vs 54.4 p = 0.49). Overall, raw material cost was also found to be lower per procedure in the SA group vs the GA group ($8.90 vs $38.8: 77% reduction). Adjusted total mean costs for the surgery were not different between groups. The reduction in opioid use postoperatively also suggests reduced cost in the management of postoperative pain in the SA group.

DISCUSSION

Total anesthesia time, opioid use, and serious complications were all significantly lower in the SA group. We did not find significant difference in total surgery cost between two groups. However, patients who had SA had better pain control and needed less rescue analgesics in the immediate postoperative period. No patients in either group were sent home with opioids.

CONCLUSION

Spinal anesthesia was found to be an equally effective and appropriate alternative to GA with many proposed benefits for common pediatric urologic procedures. With further research, SA may prove to be a safer alternative in patients at risk for complications related to GA general anesthesia while also offering a cost benefit.

Analgesia and Sedation in Newborns with Long-Term Mechanical Ventilation

Relevant data on drugs used for analgesia and sedation in newborns in the intensive care units during mechanical ventilation is presented. The overview of studies on the most common sedatives and analgesics (opioids, acetaminophen, ketamine, midazolam, dexmedetomidine, propofol) is provided. Analysis of their efficacy and risk of short-term and long-term adverse effects is presented, including those associated with the child’s nervous system development. The use of drugs both as monotherapy and in combination with other medications for analgesia and sedation is being discussed.

Identification of YWHAH as a Novel Brain-Derived Extracellular Vesicle Marker Post Long-Term Midazolam Exposure during Early Development

Recently, the long-term use of sedative agents in the neonatal intensive care unit (NICU) has raised concerns about neurodevelopmental outcomes in exposed neonates. Midazolam (MDZ), a common neonatal sedative in the NICU, has been suggested to increase learning disturbances and cognitive impairment in children. However, molecular mechanisms contributing to such outcomes with long-term MDZ use during the early stages of life remain unclear. In this study, we for the first time elucidate the role of brain-derived extracellular vesicles (BDEVs), including mining the BDEV proteome post long-term MDZ exposure during early development. Employing our previously established rodent model system that mimics the exposure of MDZ in the NICU using an increasing dosage regimen, we isolated BDEVs from postnatal 21-days-old control and MDZ groups using a differential sucrose density gradient. BDEVs from the control and MDZ groups were then characterized using a ZetaView nanoparticle tracking analyzer and transmission electron microscopy analysis. Next, using RT-qPCR, we examined the expression of key ESCRT-related genes involved in EV biogenesis. Lastly, using quantitative mass spectrometry-based proteomics, we mined the BDEV protein cargo that revealed key differentially expressed proteins and associated molecular pathways to be altered post long-term MDZ exposure. Our study characterized the proteome in BDEV cargo from long-term MDZ exposure at early development. Importantly, we identified and validated the expression of YWHAH as a potential target for further characterization of its downstream mechanism and a potential biomarker for the early onset of neurodevelopment and neurodegenerative diseases. Overall, the present study demonstrated long-term exposure to MDZ at early development stages could influence BDEV protein cargo, which potentially impact neural functions and behavior at later stages of development.

Effect of Combined Epidural Morphine and Midazolam on Postoperative Pain in Patients Undergoing Major Abdominal Cancer Surgery

OBJECTIVE

The objective was to compare analgesic effect of combined epidural morphine-midazolam with either drug alone on postoperative pain in patients undergoing major abdominal cancer surgery.

MATERIALS AND METHODS

Eighty-four patients were allocated in prospective randomized double-blind study to receive epidural analgesia. Patients received 5 mg morphine in morphine (Mor) group, 5 mg midazolam in midazolam (Mid) group, 5 mg morphine + 5 mg midazolam in morphine-midazolam (MM) group, 0.25% bupivacaine was added to injected solution with same volume in all groups. All groups were compared with time of first analgesic request, total analgesic consumption, number of epidural doses, postoperative Visual Analog Scale score, and adverse events.

RESULTS

Time of first analgesic request was 4 to 8 hours in Mid versus 12 to 23 and 14 to 24 hours in Mor and MM groups, respectively, with significant difference between Mid versus Mor ( P <0.001), Mid versus MM ( P <0.001), and Mor versus MM groups ( P <0.031). Analgesic consumption was more in Mid than Mor and MM groups, with significant difference between Mid versus Mor ( P <0.008), Mid versus MM ( P <0.001), with no significant difference between Mor and MM groups ( P <0.6). The number of epidural doses in Mid was 1 to 3 versus 1 to 3, and 1 to 2 in Mor and MM groups, respectively, with significant difference between Mid versus Mor ( P <0.025), Mid versus MM ( P <0.004), with no significant difference between Mor and MM groups ( P =1.0).

CONCLUSIONS

Addition of midazolam to epidural morphine prolonged time of first analgesic request and decreased total analgesic consumption.

Drug Repurposing: The Mechanisms and Signaling Pathways of Anti-Cancer Effects of Anesthetics

Cancer is one of the leading causes of death worldwide. There are only limited treatment strategies that can be applied to treat cancer, including surgical resection, chemotherapy, and radiotherapy, but these have only limited effectiveness. Developing a new drug for cancer therapy is protracted, costly, and inefficient. Recently, drug repurposing has become a rising research field to provide new meaning for an old drug. By searching a drug repurposing database ReDO_DB, a brief list of anesthetic/sedative drugs, such as haloperidol, ketamine, lidocaine, midazolam, propofol, and valproic acid, are shown to possess anti-cancer properties. Therefore, in the current review, we will provide a general overview of the anti-cancer mechanisms of these anesthetic/sedative drugs and explore the potential underlying signaling pathways and clinical application of these drugs applied individually or in combination with other anti-cancer agents.

Neonatal seizures treatment based on conventional multichannel EEG monitoring: an overview of therapeutic options

INTRODUCTION

Seizures are the main neurological emergency during the neonatal period and are mostly acute and focal. The prognosis mainly depends on the underlying etiology. Conventional multichannel video-electroencephalographic (cEEG) monitoring is the gold standard for diagnosis, but treatment remains a challenge.

AREAS COVERED

This review, based on PubMed search over the last 4 decades, focuses on the current treatment options for neonatal seizures based on cEEG monitoring. There is still no consensus on seizure therapy, owing to poor scientific evidence. Traditionally, the first-line treatments are phenobarbital and phenytoin, followed by midazolam and lidocaine, but their efficacy is limited. Therefore, current evidence strongly suggests the use of alternative antiseizure medications. Randomized controlled trials of new drugs are ongoing.

EXPERT OPINION

Therapy for neonatal seizures should be prompt and tailored, based on semeiology, mirror of the underlying cause, and cEEG features. Further research should focus on antiseizure medications that directly act on the etiopathogenetic mechanism responsible for seizures and are therefore more effective in seizure control.

Midazolam Suppresses Hepatocellular Carcinoma Cell Metastasis and Enhances Apoptosis by Elevating miR-217

Background

Hepatocellular carcinoma (HCC) is a significant cause of human death in the world. Recently, it is found that midazolam can modulate miRs to participate in HCC progression. This research project was designed to elucidate the impacts of midazolam and miR-217 on HCC cell metastasis and apoptosis.

Methods

Human HCC cell strains (Hep3B and SK-HEP-1) were selected and intervened by midazolam at different concentrations in our research. miR-217-inhibitor intervened in the two HCC cell strains to observe the alterations of cell migration, invasiveness, and apoptosis. The miR-217 level in HCC cells was identified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

Results

As midazolam concentration was elevated, Hep3B and SK-HEP-1 viabilities were more obviously suppressed. The 10 μg/mL concentration was selected for analysis since Hep3B and SK-HEP-1 had an IC50 of 10.57 μg/mL and 9.35 μg/m, respectively. The qRT-PCR results showed the decreased of miR-217 in HCC cells, which was enhanced notably by midazolam intervention. Compared with the blank group, the invasiveness and migration (Transwell assay) of miR-217-inhibitor-transfected HCC cells were distinctly enhanced and the apoptosis rate (flow cytometry) was noticeably reduced.

Conclusion

Midazolam can upregulate miR-217 in HCC cells, thus inhibiting HCC cell metastasis and apoptosis.

The Options for Neuraxial Drug Administration

Neuraxial drug administration, i.e., the injection of drugs into the epidural or intrathecal space to produce anesthesia or analgesia, is a technique developed more than 120 years ago. Today, it still is widely used in daily practice in anesthesiology and in acute and chronic pain therapy. A multitude of different drugs have been introduced for neuraxial injection, only a part of which have obtained official approval for that indication. A broad understanding of the pharmacology of those agents is essential to the clinician to utilize them in a safe and efficient manner. In the present narrative review, we summarize current knowledge on neuraxial anatomy relevant to clinical practice, including pediatric anatomy. Then, we delineate the general pharmacology of neuraxial drug administration, with particular attention to specific aspects of epidural and intrathecal pharmacokinetics and pharmacodynamics. Furthermore, we describe the most common clinical indications for neuraxial drug administration, including the perioperative setting, obstetrics, and chronic pain. Then, we discuss possible neurotoxic effects of neuraxial drugs, and moreover, we detail the specific properties of the most commonly used neuraxial drugs that are relevant to clinicians who employ epidural or intrathecal drug administration, in order to ensure adequate treatment and patient safety in these techniques. Finally, we give a brief overview on new developments in neuraxial drug therapy.

Modulators of TRPM7 and its potential as a drug target for brain tumours

TRPM7 is a non-selective divalent cation channel with an alpha-kinase domain. Corresponding with its broad expression, TRPM7 has a role in a wide range of cell functions, including proliferation, migration, and survival. Growing evidence shows that TRPM7 is also aberrantly expressed in various cancers, including brain cancers. Because ion channels have widespread tissue distribution and result in extensive physiological consequences when dysfunctional, these proteins can be compelling drug targets. In fact, ion channels comprise the third-largest drug target type, following enzymes and receptors. Literature has shown that suppression of TRPM7 results in inhibition of migration, invasion, and proliferation in several human brain tumours. Therefore, TRPM7 presents a potential target for therapeutic brain tumour interventions. This article reviews current literature on TRPM7 as a potential drug target in the context of brain tumours and provides an overview of various selective and non-selective modulators of the channel relevant to pharmacology, oncology, and ion channel function.

Anticancer Effects of Midazolam on Lung and Breast Cancers by Inhibiting Cell Proliferation and Epithelial-Mesenchymal Transition

Despite improvements in cancer treatments resulting in higher survival rates, the proliferation and metastasis of tumors still raise new questions in cancer therapy. Therefore, new drugs and strategies are still needed. Midazolam (MDZ) is a common sedative drug acting through the γ-aminobutyric acid receptor in the central nervous system and also binds to the peripheral benzodiazepine receptor (PBR) in peripheral tissues. Previous studies have shown that MDZ inhibits cancer cell proliferation but increases cancer cell apoptosis through different mechanisms. In this study, we investigated the possible anticancer mechanisms of MDZ on different cancer cell types. MDZ inhibited transforming growth factor β (TGF-β)-induced cancer cell proliferation of both A549 and MCF-7 cells. MDZ also inhibited TGF-β-induced cell migration, invasion, epithelial-mesenchymal-transition, and Smad phosphorylation in both cancer cell lines. Inhibition of PBR by PK11195 rescued the MDZ-inhibited cell proliferation, suggesting that MDZ worked through PBR to inhibit TGF-β pathway. Furthermore, MDZ inhibited proliferation, migration, invasion and levels of mesenchymal proteins in MDA-MD-231 triple-negative breast cancer cells. Together, MDZ inhibits cancer cell proliferation both in epithelial and mesenchymal types and EMT, indicating an important role for MDZ as a candidate to treat lung and breast cancers.

Midazolam Exposure Impedes Oligodendrocyte Development via the Translocator Protein and Impairs Myelination in Larval Zebrafish

Anesthetics are commonly used in various medical procedures. Accumulating evidence suggests that early-life anesthetics exposure in infants and children affects brain development, causing psychiatric and neurological disorders. However, the underlying mechanisms are poorly understood. Using zebrafish larvae as a model, we found that the proliferation and migration of oligodendrocyte progenitor cells (OPCs) were severely impaired by the exposure of midazolam (MDZ), an anesthetic widely used in pediatric surgery and intensive care medicine, leading to a reduction of oligodendroglial lineage cell in the dorsal spinal cord. This defect was mimicked by the bath application of translocator protein (TSPO) agonists and partially rescued by genetic downregulation of TSPO. Cell transplantation experiments showed that requirement of TSPO for MDZ-induced oligodendroglial lineage cell defects is cell-autonomous. Furthermore, transmission electron microscopy and in vivo electrophysiological recording experiments demonstrated that MDZ exposure caused axon hypomyelination and action potential propagation retardation, resulting in delayed behavior initiation. Thus, our findings reveal that MDZ affects oligodendroglial lineage cell development and myelination in young animals, raising the care about its clinic use in infants and children.

Midazolam's Effects on Delayed-Rectifier K+ Current and Intermediate-Conductance Ca2+-Activated K+ Channel in Jurkat T-lymphocytes

Midazolam (MDZ) could affect lymphocyte immune functions. However, the influence of MDZ on cell’s K⁺ currents has never been investigated. Thus, in the present study, the effects of MDZ on Jurkat T lymphocytes were studied using the patch-clamp technique. Results showed that MDZ suppressed the amplitude of delayed-rectifier K⁺ current (I_K(DR)) in concentration-, time-, and state-dependent manners. The IC₅₀ for MDZ-mediated reduction of I_K(DR) density was 5.87 μM. Increasing MDZ concentration raised the rate of current-density inactivation and its inhibitory action on I_K(DR) density was estimated with a dissociation constant of 5.14 μM. In addition, the inactivation curve of I_K(DR) associated with MDZ was shifted to a hyperpolarized potential with no change on the slope factor. MDZ-induced inhibition of I_K(DR) was not reversed by flumazenil. In addition, the activity of intermediate-conductance Ca²⁺-activated K⁺ (IK_Ca) channels was suppressed by MDZ. Furthermore, inhibition by MDZ on both I_K(DR) and IK_Ca-channel activity appeared to be independent from GABAA receptors and affected immune-regulating cytokine expression in LPS/PMA-treated human T lymphocytes. In conclusion, MDZ suppressed current density of I_K(DR) in concentration-, time-, and state-dependent manners in Jurkat T-lymphocytes and affected immune-regulating cytokine expression in LPS/PMA-treated human T lymphocytes.

Combined Effect of Midazolam and Bone Morphogenetic Protein-2 for Differentiation Induction from C2C12 Myoblast Cells to Osteoblasts

In drug repositioning research, a new concept in drug discovery and new therapeutic opportunities have been identified for existing drugs. Midazolam (MDZ) is an anesthetic inducer used for general anesthesia. Here, we demonstrate the combined effects of bone morphogenetic protein-2 (BMP-2) and MDZ on osteogenic differentiation. An immortalized mouse myoblast cell line (C2C12 cell) was cultured in the combination of BMP-2 and MDZ (BMP-2+MDZ). The differentiation and signal transduction of C2C12 cells into osteoblasts were investigated at biological, immunohistochemical, and genetic cell levels. Mineralized nodules formed in C2C12 cells were characterized at the crystal engineering level. BMP-2+MDZ treatment decreased the myotube cell formation of C2C12 cells, and enhanced alkaline phosphatase activity and expression levels of osteoblastic differentiation marker genes. The precipitated nodules consisted of randomly oriented hydroxyapatite nanorods and nanoparticles. BMP-2+MDZ treatment reduced the immunostaining for both α1 and γ2 subunits antigens on the gamma-aminobutyric acid type A (GABAA) receptor in C2C12 cells, but enhanced that for BMP signal transducers. Our investigation showed that BMP-2+MDZ has a strong ability to induce the differentiation of C2C12 cells into osteoblasts and has the potential for drug repositioning in bone regeneration.

Dexmedetomidine Alleviates Neurogenesis Damage Following Neonatal Midazolam Exposure in Rats through JNK and P38 MAPK Pathways

Midazolam, a widely used anesthetic, inhibits proliferation of neural stem cells (NSCs) and induces neuroapoptosis in neonates. Dexmedetomidine, an effective auxiliary medicine in clinical anesthesia, protects the developing brain against volatile anesthetic-induced neuroapoptosis. Whether dexmedetomidine protects against neurogenesis damage induced by midazolam remains unknown. This study aims to clarify the protective effect of dexmedetomidine on midazolam-induced neurogenesis damage and explore its potential mechanism. Postnatal 7-day-old Sprague-Dawley (SD) rats and cultured NSCs were treated with either normal saline, midazolam, or dexmedetomidine combined with midazolam. The rats were sacrificed at 1, 3, and 7 days after treatment. Cell proliferation was assessed by 5-bromodeoxyurdine (BrdU) incorporation. Cell viability was determined using MTT assay. Cell differentiation and apoptosis were detected by immunofluorescent staining and terminal dUTP nick-end labeling (TUNEL), respectively. The protein levels of p-JNK, p-P38, and cleaved caspase-3 were quantified using Western blotting. Midazolam decreased cell proliferation and increased cell apoptosis in the subventricular zone (SVZ), the subgranular zone (SGZ) of the hippocampus, and cultured NSCs. Moreover, midazolam decreased cell viability and increased the expression of p-JNK and p-P38 in cultured NSCs. Co-treatment with dexmedetomidine attenuated midazolam-induced changes in cell proliferation, viability, apoptosis, and protein expression of p-JNK and p-P38 in cultured NSCs. Midazolam and dexmedetomidine did not affect the differentiation of the cultured NSCs. These results indicate that dexmedetomidine alleviated midazolam-induced neurogenesis damage via JNK and P38 MAPK pathways.

Comparison of Systemic Effects of Midazolam, Ketamine, and Isoflurane Anaesthesia in Rabbits

Introduction

Clinical doses of anaesthetic agents were administered to rabbits and effects on the brain, heart, and liver were investigated biochemically and histopathologically.

Material and Methods

The rabbits were randomly divided into three main groups (16 rabbits each) and each group into study (n = 8) and control (n = 8) groups. All study group rabbits received 3 mg/kg of midazolam (M) intramuscularly. Group 1.1 (M) received nothing further, group 2.1 (MK) also received 25 mg/kg of ketamine, and group 3.1 (MKI) besides ketamine was also given 2% isoflurane to induce anaesthesia for 30 min. NaCl solution in the same volume as midazolam and ketamine was injected into the controls.

Results

In clinical evaluation significant differences were detected in respiratory and heart rates. In blood gas analysis the PO₂ and PCO₂ values showed statistical differences in anaesthesia intervals. Significant biochemical value changes were recorded in creatine kinase-Mb, glucose, and total protein. Histopathological liver examinations revealed higher total apoptotic and normal cell numbers in the MK than in the M and MKI groups. Apoptotic cell numbers were statistically significant in M and MK groups.

Conclusion

Anaesthetic agents may increase programmed apoptosis. The MKI anaesthetics combination was found to cause less cell destruction in general than the other study groups. It was indicated that MKI was the safer anaesthetic combination in rabbits.

Pretreatment with minocycline improves neurogenesis and behavior performance after midazolam exposure in neonatal rats

Laboratory studies suggested that general anesthetics induce neuroapoptosis and inhibit neurogenesis in developing brains of animals. Minocycline exerts neuroprotection against a wide range of toxic insults in neurodegenerative diseases models. Here, we investigate whether minocycline can alleviate neurogenetic damage and improve cognition following midazolam exposure in neonatal rats. Postnatal 7 days rats were divided randomly into three groups: control group (C), midazolam group (M), and minocycline pretreatment group (MP). After exposure to midazolam, the cell proliferation in the subventricular zone (SVZ) and the subgranular zone (SGZ) of the hippocampus in pups was analyzed by bromodeoxyuridine immunochemistry at 7 days after the administration of anesthesia. Cognitive function was assessed using the Morris water-maze test at 35 days after midazolam exposure. Compared with the control, midazolam reduced cell proliferation both in the SVZ and in the SGZ of the hippocampus of neonatal rats, and decreased spatial learning and memory ability of rats in adulthood significantly. Pretreatment with minocycline increased cell proliferation both in the SVZ and in the SGZ of the hippocampus and improved spatial learning and memory ability compared with midazolam, but it did not mitigate the changes to the normal levels compared with the controls. Our results indicated that pretreatment with minocycline can alleviate midazolam-induced damage in neural stem cell proliferation of neonatal rats and improve spatial learning and memory ability of rats in adulthood.

Status Epilepticus in the Neonate: Updates in Treatment Strategies

PURPOSE OF REVIEW

The purpose of this review is to report recent advances in treatment of neonatal seizures, with a specific focus on new literature since a 2013 systematic review performed by this author (Slaughter) and others. There is a paucity of data with regard to well-defined status epilepticus (SE) in neonates, so treatment of recurrent seizures was also included in this inquiry. We aimed to summarize the efficacy and safety profiles of current therapeutic options as well as describe trends in medication selection in the neonatal intensive care unit (NICU) setting.

RECENT FINDINGS

Phenobarbital remains first-line therapy in practice, though there is increasing evidence of its neurotoxicity and long-term sequelae. Bumetanide failed an open-label trial for efficacy, demonstrated an increased risk for hearing loss, and has since fallen out of favor for use in this population. New agents, such as levetiracetam and topiramate, still have very limited data but appear to be as efficacious as older medications, with more favorable side effect profiles. There are limited high-level evidence-based data to guide treatment of neonatal seizures. Emerging research focusing on drug mechanisms and safety profiles may provide additional information to guide decisions; however, further research is needed.

Potential for Drug Repositioning of Midazolam for Dentin Regeneration

Drug repositioning promises the advantages of reducing costs and expediting approval schedules. An induction of the anesthetic and sedative drug; midazolam (MDZ), regulates inhibitory neurotransmitters in the vertebrate nervous system. In this study we show the potential for drug repositioning of MDZ for dentin regeneration. A porcine dental pulp-derived cell line (PPU-7) that we established was cultured in MDZ-only, the combination of MDZ with bone morphogenetic protein 2, and the combination of MDZ with transforming growth factor-beta 1. The differentiation of PPU-7 into odontoblasts was investigated at the cell biological and genetic level. Mineralized nodules formed in PPU-7 were characterized at the protein and crystal engineering levels. The MDZ-only treatment enhanced the alkaline phosphatase activity and mRNA levels of odontoblast differentiation marker genes, and precipitated nodule formation containing a dentin-specific protein (dentin phosphoprotein). The nodules consisted of randomly oriented hydroxyapatite nanorods and nanoparticles. The morphology, orientation, and chemical composition of the hydroxyapatite crystals were similar to those of hydroxyapatite that had transformed from amorphous calcium phosphate nanoparticles, as well as the hydroxyapatite in human molar dentin. Our investigation showed that a combination of MDZ and PPU-7 cells possesses high potential of drug repositioning for dentin regeneration.

Midazolam and Dexmedetomidine Affect Neuroglioma and Lung Carcinoma Cell Biology In Vitro and In Vivo

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

Several factors within the perioperative period may influence postoperative metastatic spread. Dexmedetomidine and midazolam are widely used general anesthetics during surgery. The authors assessed their effects on human lung carcinoma (A549) and neuroglioma (H4) cell lines in vitro and in vivo.

Methods

Cell proliferation and migration were measured after dexmedetomidine (0.001 to 10 nM) or midazolam (0.01 to 400 μM) treatment. Expression of cell cycle and apoptosis markers were assessed by immunofluorescence. Mitochondrial membrane potential and reactive oxygen species were measured by JC-1 staining and flow cytometry. Antagonists atipamezole and flumazenil were used to study anesthetic mechanisms of action. Tumor burden after anesthetic treatment was investigated with a mouse xenograft model of lung carcinoma.

Results

Dexmedetomidine (1 nM) promoted cell proliferation (2.9-fold in A549 and 2-fold in H4 cells vs. vehicle, P &lt; 0.0001; n = 6), migration (2.2-fold in A549 and 1.9-fold in H4 cells vs. vehicle, P &lt; 0.0001; n = 6), and upregulated antiapoptotic proteins in vitro. In contrast, midazolam (400 μM) suppressed cancer cell migration (2.6-fold in A549 cells, P &lt; 0.0001; n = 4), induced apoptosis via the intrinsic mitochondrial pathway, decreased mitochondrial membrane potential, and increased reactive oxygen species expression in vitro—effects partly attributable to peripheral benzodiazepine receptor activation. Furthermore, midazolam significantly reduced tumor burden in mice (1.7-fold vs. control; P &lt; 0.05; n = 6 per group).

Conclusions

Midazolam possesses antitumorigenic properties partly mediated by the peripheral benzodiazepine receptor, whereas dexmedetomidine promotes cancer cell survival through signaling via the α2-adrenoceptor in lung carcinoma and neuroglioma cells.

Propofol, but not ketamine or midazolam, exerts neuroprotection after ischaemic injury by inhibition of Toll-like receptor 4 and nuclear factor kappa-light-chain-enhancer of activated B-cell signalling: A combined in vitro and animal study

BACKGROUND

Propofol, midazolam and ketamine are widely used in today's anaesthesia practice. Both neuroprotective and neurotoxic effects have been attributed to all three agents.

OBJECTIVE

To establish whether propofol, midazolam and ketamine in the same neuronal injury model exert neuroprotective effects on injured neurones in vitro and in vivo by modulation of the Toll-like receptor 4-nuclear factor kappa-light-chain-enhancer of activated B cells (TLR-4-NF-κB) pathway.

DESIGN AND SETTING

Cell-based laboratory (n = 6 repetitions per experiment) and animal (n = 6 per group) studies using a neuronal cell line (SH-SY5Y cells) and adult Sprague-Dawley rats.

INTERVENTIONS

Cells were exposed to oxygen-glucose deprivation before or after treatment using escalating, clinically relevant doses of propofol, midazolam and ketamine. In animals, retinal ischaemia (60 min) was induced followed by reperfusion and randomised treatment with saline or propofol.

MAIN OUTCOME MEASURES

Neuronal cell death was determined using flow-cytometry (mitochondrial membrane potential) and lactate dehydrogenase (LDH) release. Nuclear factor NF-κB and hypoxia-inducible factor 1 α-activity were analysed by DNA-binding ELISA, expression of NF-κB-dependent genes and TLR-4 by luciferase-assay and flow-cytometry, respectively. In animals, retinal ganglion cell density, caspase-3 activation and gene expression (TLR-4, NF-κB) were used to determine in vivo effects of propofol. Results were compared using ANOVA (Analysis of Variance) and t test. A P value less than 0.05 was considered statistically significant.

RESULTS

Post-treatment with clinically relevant concentrations of propofol (1 to 10 μg ml) preserved the mitochondrial membrane potential in oxygen-glucose deprivation-injured cells by 54% and reduced LDH release by 21%. Propofol diminished TLR-4 surface expression and preserved the DNA-binding activity of the protective hypoxia-inducible factor 1 α transcription factor. DNA-binding and transcriptional NF-κB-activity were inhibited by propofol. Neuronal protection and inhibition of TLR-4-NF-κB signalling were not consistently seen with midazolam or ketamine. In vivo, propofol treatment preserved rat retinal ganglion cell densities (cells mm, saline 1504 ± 251 vs propofol 2088 ± 144, P = 0.0001), which was accompanied by reduced neuronal caspase-3, TLR-4 and NF-κB expression.

CONCLUSION

Propofol, but neither midazolam nor ketamine, provides neuroprotection to injured neuronal cells via inhibition of TLR-4-NF-κB-dependent signalling.

Propofol Protects Rat Hypoglossal Motoneurons in an In Vitro Model of Excitotoxicity by Boosting GABAergic Inhibition and Reducing Oxidative Stress

In brainstem motor networks, hypoglossal motoneurons (HMs) play the physiological role of driving tongue contraction, an activity critical for inspiration, phonation, chewing and swallowing. HMs are an early target of neurodegenerative diseases like amyotrophic lateral sclerosis that, in its bulbar form, is manifested with initial dysphagia and dysarthria. One important pathogenetic component of this disease is the high level of extracellular glutamate due to uptake block that generates excitotoxicity. To understand the earliest phases of this condition we devised a model, the rat brainstem slice, in which block of glutamate uptake is associated with intense bursting of HMs, dysmetabolism and death. Since blocking bursting becomes a goal to prevent cell damage, the present report enquired whether boosting GABAergic inhibition could fulfill this aim and confer beneficial outcome. Propofol (0.5 µM) and midazolam (0.01 µM), two allosteric modulators of GABA_A receptors, were used at concentrations yielding analogous potentiation of GABA-mediated currents. Propofol also partly depressed NMDA receptor currents. Both drugs significantly shortened bursting episodes without changing single burst properties, their synchronicity, or their occurrence. Two hours later, propofol prevented the rise in reactive oxygen species (ROS) and, at 4 hours, it inhibited intracellular release of apoptosis-inducing factor (AIF) and prevented concomitant cell loss. Midazolam did not contrast ROS and AIF release. The present work provides experimental evidence for the neuroprotective action of a general anesthetic like propofol, which, in this case, may be achieved through a combination of boosted GABAergic inhibition and reduced ROS production.

Midazolam prevents motor neuronal death from oxidative stress attack mediated by JNK-ERK pathway

Midazolam is a sedative used by patients with mechanical ventilation. However, the potential clinical value is not fully explored. In this report, we made use of a neuroblastoma-spinal cord hybrid motor neuron-like cell line NSC34, and elucidated the potential role of Midazolam on these cells under the insult of oxidative stress. We found the protective effect of Midazolam on motor neurons against cytotoxicity induced by the combination of oligomycin A and rotenone (O/R) or phenylarsine oxide. The characteristics of apoptosis, such as the ratio of TUNEL+ cells or the expression level of cleaved Caspase-3, was decreased by 22 or 45% in the presence of Midazolam. Furthermore, this effect was correlated with the JNK-ERK signaling pathway. Either phosphorylation of ERK or JNK was positively or negatively modulated with the treatment of Midazolam in NSC34 cells attacked by reactive oxygen species. Meanwhile, inhibition or activation of the JNK-ERK pathway regulated the protective effect of Midazolam on NSC34 cells with oxidative stress insult. Collectively, this study elucidated a previously unidentified clinical effect of Midazolam, and put forward the great promise that Midazolam may be considered as a potential candidate to the treatment of motor neuron disease.

Spinal anesthesia for pediatric urological surgery: Reducing the theoretic neurotoxic effects of general anesthesia

BACKGROUND

Spinal anesthesia (SA) is an effective technique that has been used in children for years. With growing concern with regard to the risks of general anesthesia (GA), we developed a SA program to provide an alternative option. We present our initial experience with this program.

OBJECTIVE

To implement a SA program at a large tertiary care pediatric center and assess the safety and efficacy of the technique as an alternative to GA for urologic surgery.

STUDY DESIGN/METHODS

We prospectively collected data on all children undergoing SA at our institution. We recorded demographics, procedure, time required for placement of the SA, length of surgery, success of lumbar puncture, success of attaining adequate surgical anesthesia, need for supplemental systemic sedation, conversion to GA, and perioperative complications.

RESULTS

SA was attempted in 105 consecutive children (104 boys, 1 girl) with a mean age of 7.4 ± 4.3 months (range 19 days-24 months) and mean weight of 8.3 ± 1.7 kg (range 3.5-13.7). Placement of the SA was successful in 93/105 children (89%). Inability to achieve lumbar puncture (cerebrospinal fluid was not obtained) meant that SA was abandoned in seven (7%) patients and GA was administered. In five patients in whom SA was successful and surgery was begun, 5/93 (5%) required conversion to GA: two because of evisceration of intestine through large hernia defects related to coughing and abdominal irritation, two because of lack of motor blockade despite an adequate sensory block, and one because of an inability to place an intravenous catheter in the lower extremities (required per SA protocol). If necessary, an intravenous catheter can be placed in the upper extremity, but this must be weighed against the fact that the block has already been placed and is of limited duration. Overall, SA was successful (SA was placed and surgery was completed without conversion to GA) in 88/105 children (84%). No additional sedation and no systemic anesthetic agents were required in 75/88 children (85%). The average time required to place the SA was 3.8 ± 2.7 min (range 1-12). The average time for the surgical procedure was 38.3 ± 23.1 min (range 10-122). No patient required conversion to GA because of recession of block. There were no surgical complications.

DISCUSSION/CONCLUSIONS

SA is a safe and efficacious technique for routine pediatric urological procedures. SA should be considered for cases such as neonatal torsion or patients with significant cardiac or pulmonary comorbidities when the risks of GA are often weighed against the risks of non-intervention.

Insights into the Roles of Midazolam in Cancer Therapy

With its high worldwide mortality and morbidity, cancer has gained increasing attention and novel anticancer drugs have become the focus for cancer research. Recently, studies have shown that most anesthetic agents can influence the activity of tumor cells. Midazolam is a γ-aminobutyric acid A (GABA_A) receptor agonist, used widely for preoperative sedation and as an adjuvant during neuraxial blockade. Some studies have indicated the potential for midazolam as a novel therapeutic cancer drug; however, the mechanism by which midazolam affects cancer cells needs to be clarified. This systematic review aims to summarize the progress in assessing the molecular mechanism of midazolam as an anticancer agent.

Isoflurane anesthesia induces liver injury by regulating the expression of insulin-like growth factor 1

It has been suggested that isoflurane may cause perioperative liver injury. However, the mechanism of its action remains unknown. The purpose of the present study was to determine this possible mechanism. Sprague-Dawley rats were randomly assigned into one of three groups (all n=12): Control group (exposed to mock anesthesia), isoflurane group (exposed to 2% isoflurane for 90 min), and isoflurane + insulin-like growth factor 1 (IGF-1) group (exposed to 2% isoflurane for 90 min and then treated with IGF-1). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were conducted to determine the levels of expression of IGF-1 and its receptor IGF-R. Liver necrosis was assessed by histological examination. TUNEL assay was performed to determine the apoptosis of hepatic cells. In addition, the levels of the proteins caspase-3 and B-cell lymphoma-extra large (Bcl-xL) were measured. Compared with the control group, levels of IGF-1 and IGF-1R mRNA and protein were significantly decreased following exposure to isoflurane (all P<0.05). The necrosis rate and liver apoptosis were significantly increased in the group treated with isoflurane alone compared with the control group (P<0.05), but were significantly decreased compared with the isoflurane group following application of IGF-1 (P<0.05). Additionally, isoflurane exposure significantly increased levels of caspase-3 compared with the control group (P<0.05), but decreased levels of Bcl-xL (P<0.05). By contrast, application of IGF-1 reversed these changes. The present study therefore suggests that isoflurane induces liver injury in part by regulating the expression of IGF-1 and that application of IGF-1 may protect against liver injury induced by isoflurane exposure.

Midazolam anesthesia protects neuronal cells from oxidative stress-induced death via activation of the JNK-ERK pathway

Midazolam is an anesthetic agent commonly used during clinical and surgical procedures, which has been shown to exert ROS-suppressing and apoptosis-modulating pharmacological activities in various cellular systems. However, the effects of midazolam on oxidative stress in neuronal cells require elucidation. The present study investigated the effects of midazolam on buthionine sulfoximine (BSO)- and hydrogen peroxide (H₂O₂)-induced oxidative stress in primary cortical neuronal cells. In addition, the effects of midazolam on middle cerebral artery occlusion (MCAO) in mice and on ethanol-induced neuroapoptosis in the brains of neonatal mice were determined. Subsequently, cell viability was detected using the MTT assay; intracellular reactive oxygen species (ROS) generation was determined using the 2′,7′-dichlorodihydrofluorescein diacetate method with confocal microscopy; terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was conducted to detect apoptotic cells; immunohistochemistry was performed to detect activated caspase-3; neuronal deficit and infarct volume analyses were conducted; and quantitative polymerase chain reaction and western blotting were performed to detect the expression levels of genes and proteins associated with apoptosis and cell survival pathways. The results demonstrated that BSO (10 mM) and H₂O₂ (1 mM) suppressed proliferation of cortical neuronal cells by inducing apoptosis. These effects were suppressed following treatment with midazolam in a dose-dependent manner. In addition, BSO and H₂O₂ induced ROS generation in neuronal cells; however, this was effectively suppressed by midazolam (100 µM). Beneficial synergistic effects were detected when midazolam was used in combination with the known antioxidant trolox. BSO and H₂O₂ also suppressed the protein expression levels of c-Jun N-terminal kinases (JNK), phosphorylated (p)JNK, extracellular signal-regulated kinases (ERK)1/2, pERK1/2, AKT and nuclear factor-κB; however, expression was recovered following treatment with midazolam. Midazolam also activated protein kinase C-ε, which was suppressed by BSO, in cortical neuronal cells. In MCAO mice, midazolam post-conditioning significantly suppressed infarct size and reduced the number of TUNEL-positive cells. In addition, the expression levels of caspase-3 and poly (ADP-ribose) polymerase were suppressed in a dose-dependent manner. In neonatal mice, midazolam reduced ethanol-induced activated caspase-3 staining and apoptotic TUNEL staining. The results of the present study demonstrated that midazolam may protect against neuronal degeneration and neuroapoptosis induced by physiological and oxidative stress.

A novel, clinically relevant use of a piglet model to study the effects of anesthetics on the developing brain

Background

Anesthesia-induced neurotoxicity research in the developing brain must rely upon an unimpeachable animal model and a standardized treatment approach. In this manner, identification of mechanisms of action may be undertaken. The goal of this study was to develop a novel, clinically relevant, translational way to use a piglet model to investigate anesthesia effects on the developing brain.

Methods

29 newborn piglets were assigned to either: (1) control (no intervention, n = 10); (2) lipopolysaccharide (LPS; positive inflammatory control, n = 9); or (3) isoflurane anesthesia (n = 10). Positive inflammatory control animals were given 100 mcg/kg LPS from Escherichia coli intraperitoneally (IP) on the same day as those receiving isoflurane. Isoflurane was administered for 3 h while care was taken to ensure human perioperative conditions. To establish a clinical scenario, each animal was intubated and monitored with pulse oximetry, invasive and non-invasive blood pressure, electrocardiogram, temperature, end-tidal CO₂, anesthetic concentration, and iSTAT blood analysis. All animals were sacrificed after 48 h using transcardiac perfusion of ice-cold, heparinized phosphate buffered saline (PBS) followed by 4 % paraformaldehyde (PFA). Brains were collected and histopathological analysis focused on the entorhinal cortex looking for degenerative changes due to its critical role in learning and memory. Reliable identification of entorhinal cortex was achieved by using colored ink on the surface of the brains, which was then cross-referenced with microscopic anatomy. Hematoxylin & eosin-stained high-power fields was used to quantify cells. ImageJ™ (National Institutes of Health, Bethesda, MD, USA) was used to count absolute number of progenitor glial cells (PGC) and number of PGCs per cluster. Immunohistochemistry was also utilized to ensure positive identification of cellular structures.

Results

Histopathological sections of 28 brains were analyzed. One animal in the LPS group died shortly after administration, presumably from inadvertent intravascular injection. There was an acute basal ganglia ischemic infarct in one isoflurane-treated animal. A large number of small, round nucleated cells were seen throughout layer II of the entorhinal cortex in all animals. These cells were identified as PGCs using immunohistochemistry and light microscopy. Although there was no difference in the absolute number of PGCs between the groups, animals given isoflurane or LPS demonstrated a significant increase in cells forming ‘clusters’ in the entorhinal cortex. An apparent change in the pattern of doublecortin labeling also suggests changes in neuronal precursors and undifferentiated neurons.

Conclusions

This study represents the first novel use of a clinically relevant neonatal piglet model to study anesthesia effects on the developing brain. LPS induces neuroinflammation, and this is a potential mechanism for LPS and perhaps isoflurane in causing a change in progenitor cell distribution. We postulate that the isoflurane-induced change in glial progenitor cell distribution could have important implications for cell differentiation, maturation and neural circuit behavior in the rapidly developing brain.

Pretreatment but not subsequent coincubation with midazolam reduces the cytotoxicity of temozolomide in neuroblastoma cells

Background

Temozolomide (TMZ) induces a G2/M cell cycle arrest and is used for treatment of paediatric tumours, especially neuroblastomas. Patients treated with TMZ frequently receive midazolam for sedation prior to surgery and other interventions. Previous studies suggested both cytoprotective and apoptosis-inducing properties of midazolam. Therefore, the impact of midazolam on TMZ-induced cytotoxicity was investigated in vitro.

Methods

Human neuroblastoma cells were incubated with midazolam alone, as a pretreatment prior to incubation with TMZ or a coincubation of both. Cell viability and proliferation was analysed (XTT and BrdU assay) after 24 h and flowcytometric cell cycle analysis was performed after 24 and 48 h.

Results

Midazolam alone increased cell viability at lower concentrations (2, 4, 8, 16 μM), whereas higher concentrations (128, 256, 512 μM) reduced cell viability. Pretreatment with midazolam 6 h prior to TMZ incubation reduced cytotoxic effects (IC₂₅ 1005 ± 197 μM; IC₅₀ 1676 ± 557 μM; P < 0.05) compared to incubation with TMZ alone (IC₂₅ 449 ± 304 μM; IC₅₀ 925 ± 196 μM) and reduced the antiproliferative effect of TMZ (1000 μM) by 43.9 % (P < 0.05). In contrast, cytotoxic effects of TMZ were increased (IC₇₅ 1175 ± 221 μM vs. 2764 ± 307 μM; P < 0.05) when midazolam pretreatment was followed by coincubation of midazolam and TMZ. Cell cycle analysis revealed increased fractions of cells in G2/M phase after TMZ treatment (100 μM; 48 h), irrespective of midazolam pretreatment.

Conclusion

Midazolam causes a hormetic dose–response relationship in human neuroblastoma cells. Pretreatment with midazolam reduces the cytotoxic and antiproliferative effects of TMZ without interfering with G2/M cell cycle arrest. In contrast, subsequent midazolam coincubation increases overall cytotoxicity.

Neuroimaging, Pain Sensitivity, and Neuropsychological Functioning in School-Age Neonatal Extracorporeal Membrane Oxygenation Survivors Exposed to Opioids and Sedatives

OBJECTIVES

Animal studies found negative long-term effects of exposure to sedatives and opioids in early life, especially when administered in the absence of pain. Around the world, children who require extracorporeal membrane oxygenation receive opioids and sedatives for extended periods, generally in the absence of major pain as extracorporeal membrane oxygenation cannulation is considered minor surgery. Therefore, our objective was to determine the long-term effects of extracorporeal membrane oxygenation treatment with respect to pain sensitivity, brain functioning during pain, brain morphology, and neuropsychological functioning in humans.

DESIGN

Prospective follow-up study.

SETTING

Level III university hospital.

SUBJECTS

Thirty-six extracorporeal membrane oxygenation survivors (8.1-15.5 yr) and 64 healthy controls (8.2-15.3 yr).

MEASUREMENTS AND MAIN RESULTS

We measured detection and pain thresholds, brain activity during pain (functional MRI), brain morphology (high-resolution structural MRI), and neuropsychological functioning and collected information regarding the subject's experience of chronic pain. We found a significant difference in the detection threshold for cold measured in a reaction time-dependent fashion (extracorporeal membrane oxygenation group, 29.9°C [SD, 1.4]; control group, 30.6°C [SD, 0.8]; p < 0.01), but no differences in other modalities or in pain sensitivity between groups. Furthermore, no differences in brain activation during pain, brain morphology, or in the occurrence of chronic pain were observed. However, extracorporeal membrane oxygenation survivors performed significantly worse on a verbal memory test compared with controls (p = 0.001).

CONCLUSIONS

While the most critically ill newborns receive extracorporeal membrane oxygenation and, relatedly, large doses of opioids and sedatives for extended periods, global measures of pain sensitivity and neurobiological and neuropsychological development appear to have minor long-term consequences. Possible memory deficits in extracorporeal membrane oxygenation survivors require additional study, but neonatal extracorporeal membrane oxygenation treatment and associated exposure to opioids and sedatives seem less harmful to humans than expected from animal studies.

Midazolam induces apoptosis in MA-10 mouse Leydig tumor cells through caspase activation and the involvement of MAPK signaling pathway

Purpose

The present study aims to investigate how midazolam, a sedative drug for clinical use with cytotoxicity on neuronal and peripheral tissues, induced apoptosis in MA-10 mouse Leydig tumor cells.

Methods

The apoptotic effect and underlying mechanism of midazolam to MA-10 cells were investigated by flow cytometry assay and Western blotting methods.

Results

Data showed that midazolam induced the accumulation of the MA-10 cell population in the sub-G1 phase and a reduction in the G2/M phase in a time- and dose-dependent manner, suggesting an apoptotic phenomenon. Midazolam could also induce the activation of caspase-8, -9, and -3 and poly (ADP-ribose) polymerase proteins. There were no changes in the levels of Bax and cytochrome-c, whereas Bid was significantly decreased after midazolam treatment. Moreover, midazolam decreased both pAkt and Akt expression. In addition, midazolam stimulated the phosphorylation of p38 and c-Jun NH2-terminal kinase but not extracellular signal-regulated kinase.

Conclusion

Midazolam could induce MA-10 cell apoptosis through the activation of caspase cascade, the inhibition of pAkt pathway, and the induction of p38 and c-Jun NH2-terminal kinase pathways.

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.

The role of anesthetic drugs in liver apoptosis

CONTEXT

The modern practice of anesthesia is highly dependent ona group of anesthetic drugs which many of them are metabolized in the liver.

EVIDENCE ACQUISITION

The liver, of course, usually tolerates this burden. However, this is not always an unbroken rule. Anesthetic induced apoptosis has gained great concern during the last years; especially considering the neurologic system.

RESULTS

However, we have evidence that there is some concern regarding their effects on the liver cells. Fortunately not all the anesthetics are blamed and even some could be used safely, based on the available evidence.

CONCLUSIONS

Besides, there are some novel agents, yet under research, which could affect the future of anesthetic agents' fate regarding their hepatic effects.

The influence of adjuvants used in regional anesthesia on lidocaine-induced neurotoxicity in vitro

BACKGROUND

Neurotoxic properties of local anesthetics can rarely lead to irreversible neuronal damage as in cauda equina syndrome. Clinically, local anesthetics are often combined with adjuvants to improve or prolong the anesthetic effect, whereas the impact of such adjuvants on lidocaine-induced apoptosis is unclear. Therefore, we investigated the influence of different adjuvants on the neurotoxicity of lidocaine.

METHODS

Human neuroblastoma cells and primary rat astrocytes were incubated for 24 hrs with lidocaine at a toxic concentration alone and in combination with morphine, sufentanil, clonidine, epinephrine, neostigmine, ketamine, and midazolam. Subsequently, the rates of cell death and early apoptosis were measured by flow cytometry in neuroblastoma cells, whereas astrocyte viability was analyzed by mitochondrial activity assay. In addition, isobolograms were calculated to describe the additive effects of lidocaine with ketamine or midazolam, respectively.

RESULTS

Coadministration of lidocaine with sufentanil, clonidine, epinephrine, and neostigmine did not alter the rates of cell death compared with cells treated with lidocaine alone. Morphine improved the viability of astrocytes only at concentrations beyond those occurring clinically. In contrast, coincubation of lidocaine with ketamine or midazolam led to significantly increased rates of cell death. The combined toxicity of ketamine and lidocaine was additive, whereas the combined toxicity of midazolam and lidocaine was subadditive.

CONCLUSIONS

Sufentanil, clonidine, epinephrine, and neostigmine do not influence the neurotoxicity of lidocaine in vitro. Morphine may have some cytoprotective effect at concentrations greater than those seen intrathecally in humans. In contrast, ketamine and midazolam increase the neurotoxicity of lidocaine in vitro, presumably by additive induction of mitochondrial apoptosis.

Midazolam protects B35 neuroblastoma cells through Akt-phosphorylation in reactive oxygen species derived cellular injury

Background

Soman, a potent irreversible acetylcholinesterase (AChE) inhibitor, induces delayed neuronal injury by reactive oxygen species (ROS). Midazolam is used in patients with pathologic effects of oxidative stresses such as infection, hemodynamic instability and hypoxia. We investigated whether midazolam protects the Central Nervous System (CNS) from soman intoxication. The present study was performed to determine whether midazolam protects B35 cells from ROS stress for the purpose of exploring an application of midazolam to soman intoxication.

Methods

Glucose oxidase (GOX) induced ROS stress was used in a B35 neuroblastoma cell model of ROS induced neuronal injury. To investigate the effect of midazolam on cell viability, LDH assays and fluorescence activated cell sorting (FACS) analysis was performed. Western blotting was used for evaluating whether Akt-phosphorylation is involved in cell-protective effects of midazolam.

Results

GOX derived ROS injury decreased cell viability about 1.6-2 times compared to control; midazolam treatment (5 and 10 µg/ml) dose-dependently increased cell viability during ROS injury. On western blots, Akt-phosphorylation was induced during pretreatment with midazolam; it was diminished during co-treatment with LY-294002, an inhibitor of Akt-phosphorylation. FACS analysis confirmed that the cell protective effect of midazolam is mediated by an anti-apoptotic effect. GOX-induced apoptosis was inhibited by midazolam and the finding was diminished by LY-294002.

Conclusions

Midazolam protects neuronal cells from GOX-induced ROS injury; this effect is mediated by an anti-apoptotic effect through Akt-phosphorylation. This shows that midazolam may be useful in soman intoxication.

Toxic effects of midazolam on differentiating neurons in vitro as a consequence of suppressed neuronal Ca2+-oscillations

BACKGROUND

In immature neurons anesthetics induce apoptosis and influence neuronal differentiation. Neuronal Ca(2+)-oscillations regulate differentiation and synaptogenesis. We examined the effects of the long-term blockade of hippocampal Ca(2+)-oscillations with midazolam on neuronal synapsin expression.

MATERIAL AND METHODS

Hippocampal neurons were incubated at day 15 in culture with the specific GABA(A) receptor agonist muscimol (50μM) or with midazolam (100 and 300nM), respectively, for 24h. TUNEL and activated-Caspase-3 staining were used to detect apoptotic neurons. Ca(2+)-oscillations were detected using the Ca(2+)-sensitive dye FURA-2 and dual wavelength excitation fluorescence microscopy. Synapsin was identified with confocal anti-synapsin immunofluorescence microscopy.

RESULTS

Muscimol, when applied for 24h, decreased the amplitude and frequency Ca(2+)-oscillations significantly. Midazolam concentration-dependently suppressed the amplitude and frequency of the Ca(2+)-oscillations. This was associated by a downregulation of the synapsin expression 24h after washout.

CONCLUSION

Neuronal Ca(2+)-oscillations mediate neuronal differentiation and are involved in synaptogenesis. By acting via the GABA(A) receptor, midazolam exerts its toxic effect through the suppression of neuronal Ca(2+)-oscillations, a reduction in synapsin expression and consecutively reduced synaptic integrity.