The experimental and clinical pharmacology of propofol, an anesthetic agent with neuroprotective properties

Immediate effects of propofol on mood: a randomized comparison of two doses in a cohort with depression

RATIONALE

The intravenous anesthetic propofol is known to induce positive mood effects during routine clinical use, suggesting it might be repurposed as an antidepressant, but also raising concerns about abuse potential. How propofol's acute effects vary by dose and with repeated infusions is unknown.

OBJECTIVES

This exploratory analysis aimed to (1) compare the immediate mood effects of propofol administered at two different doses, (2) describe how those mood effects change with repeated infusions, and (3) evaluate whether acute mood improvement predicts later antidepressant response.

METHODS

Twenty-four adults with moderate-to-severe treatment-resistant depression were randomized into two dosing groups. Six low- or high-dose propofol infusions were administered under blinded conditions over a two-week period. Self-reported mood states were recorded before and after each infusion using the Positive and Negative Affect Schedule (PANAS-X). Abuse potential was evaluated with the Drug Effects Questionnaire (DEQ-5).

RESULTS

At the first infusion, propofol induced acute improvements in PANAS-X Sadness, Fear, Joviality, and Serenity scales (p < 0.002), independent of dose. Over the series of six infusions, acute changes in Sadness, Fear, and Joviality, but not Serenity, diminished with infusion number (p < 0.002). The DEQ-5 "want more" rating decreased across infusions (p = 0.002). Changes in PANAS-X scales with the first infusion did not predict later improvement in depression severity (p > 0.05).

CONCLUSION

Cumulative changes in mood states observed with repeated infusions suggest that propofol engages adaptive mechanisms in mood circuitry. Subjective responses with repeated infusions do not indicate increasing potential for abuse in this patient population.

Perioperative dexmedetomidine-induced delirium in a patient with schizophrenia: a case report

BACKGROUND

Dexmedetomidine is a selective α2 receptor agonist with sedative, analgesic, anxiolytic, and anti-sympathetic effects. Dexmedetomidine is widely used for various surgical procedures performed under general anaesthesia and sedation in the intensive care unit. Dexmedetomidine was known to relieve or improve the symptoms of delirium. Schizophrenia is a common psychiatric disease, and the number of surgical patients with schizophrenia is increasing gradually. Dexmedetomidine-induced delirium in patients with schizophrenia is a particular case.

CASE PRESENTATION

This patient was a 75-year-old woman (height: 156 cm; weight: 60 kg) with a 5-year history of schizophrenia. Her schizophrenia was well controlled with medications. She was scheduled for open reduction and internal fixation for a patellar fracture. Spinal anaesthesia was administered for surgery, and dexmedetomidine was administered intravenously to maintain sedation. The patient became delirious half an hour after the surgery began. The intravenous infusion of dexmedetomidine was discontinued immediately, intravenous propofol was subsequently administered, and the patient stopped experiencing dysphoria and fell asleep. After surgery, the patient stopped using propofol and recovered smoothly. She was transferred back to the general ward and was discharged from the hospital without any abnormal conditions on the 9th day after surgery.

CONCLUSIONS

To the best of our knowledge, this is the first report of a patient with schizophrenia who developed delirium during the infusion of a normal dose of dexmedetomidine without an intravenous injection of any other sedative. The exact mechanism causing dexmedetomidine-induced delirium remains unclear, and this adverse reaction is rare and easy to ignore. Clinicians and pharmacists should be vigilant in identifying this condition.

Cardiopulmonary function, anesthetic effects, quality of arousal, hematology, and blood biochemistry during continuous intravenous infusion of a combination solution of xylazine, butorphanol, and propofol in calves

General anesthesia in calves is easier to perform under field conditions, total intravenous anesthesia (TIVA) than using inhalation anesthesia. In the present study, cardiopulmonary function, anesthetic effects, quality of arousal, hematology, and blood biochemistry were assessed during continuous infusion of a combination solution of 0.01% xylazine, 0.001% butorphanol, and 0.2% propofol (XBP) at doses of 6 (G6; 10 μg/kg/min xylazine, 1 μg/kg/min butorphanol, 200 μg/kg/min propofol) and 9 mL/kg/h (G9; 15 μg/kg/min xylazine, 1.5 μg/kg/min butorphanol 300 μg/kg/min propofol). For both groups, five castrated Holstein calves received intravenous injections of xylazine (0.2 mg/kg) and propofol (2 mg/kg), followed by a continuous infusion of XBP for 60 min to maintain anesthesia. Respiratory management consisted of tracheal intubation followed by spontaneous inhalation of pure oxygen. Cardiopulmonary, anesthesia, hematology, and blood biochemistry variables were assessed at rest (baseline) and every 5 or 15 min after the start of the XBP infusion. Quality of arousal was assessed based on the swallowing reflex recovery time from the stop of XBP infusion, and the sternal position time and standing time after atipamezole administration. XBP produced adequate sedation, analgesia, and muscle relaxation in all calves and maintained stable anesthesia for 60 min. As XBP infusion time passed, rectal temperature and heart rate became lower, and mean arterial blood pressure increased. In both groups, hematologic and blood biochemical effects were mild. The quality of arousal was not different, and all calves were standing. The results of the present study suggested that XBP is useful for TIVA in calves.

The Influence of CYP2B6 Variants and Administration of Propofol on Patient Outcomes after Traumatic Brain Injury

Management of severe traumatic brain injury (sTBI) typically involves the use of sedation, which inherently results in benefits and risks. The cytochrome P450 enzyme CYP2B6 is involved in the biotransformation of particular drug classes, including many intravenous sedatives. Variants of the CYP2B6 gene can lead to decreased systemic clearance of some sedatives, including propofol. This study aimed to investigate the relationship of CYP2B6 gene variation and patient outcomes after TBI while also considering propofol administration. Patients who sustained a non-penetrating sTBI and admitted to a single-center Level 1 trauma hospital were included in this study (n = 440). The *6 functional allele of CYP2B6 that leads to reduced enzyme expression and activity required genotyping two single nucleotide polymorphisms, rs3745274 and rs2279343. Patient outcomes were evaluated using the Glasgow Outcome Scale (GOS) and Disability Rating Scale (DRS) at 3 and 6 months post-injury. Data on sedative administration were abstracted from medical records. Individuals homozygous for the alleles coding for the reduced enzyme expression and activity were more likely to have worse outcomes. A relationship between propofol administration and 3-month GOS and 6-month DRS was noted when controlling for CYP2B6 genotype. These findings suggest that genetic variation in CYP2B6 may influence the impact of intravenous sedation on patient outcomes after TBI and warrants further investigation.

Acute Lung Injury and the NLRP3 Inflammasome

Acute lung injury (ALI) manifests through harm to the capillary endothelium and alveolar epithelial cells, arising from a multitude of factors, leading to scattered interstitial alterations, pulmonary edema, and subsequent acute hypoxic respiratory insufficiency. Acute lung injury (ALI), along with its more serious counterpart, acute respiratory distress syndrome (ARDS), carry a fatality rate that hovers around 30-40%. Its principal pathological characteristic lies in the unchecked inflammatory reaction. Currently, the main strategies for treating ALI are alleviation of inflammation and prevention of respiratory failure. Concerning the etiology of ALI, NLRP3 Inflammasome is essential to the body's innate immune response. The composition of this inflammasome complex includes NLRP3, the pyroptosis mediator ASC, and pro-caspase-1. Recent research has reported that the inflammatory response centered on NLRP3 inflammasomes plays a key part in inflammation in ALI, and may hence be a prospective candidate for therapeutic intervention. In the review, we present an overview of the ailment characteristics of acute lung injury along with the constitution and operation of the NLRP3 inflammasome within this framework. We also explore therapeutic strategies targeting the NLRP3 inflammasome to combat acute lung injury.

Hemophagocytic lymphohistiocytosis/cytokine release syndrome secondary to neoadjuvant pembrolizumab for triple-negative breast cancer: a case study

As indications for immune checkpoint inhibitors for breast cancer continue to expand, rare toxicities will emerge that require careful consideration and multidisciplinary management. We report the case of a 40-year-old female receiving neoadjuvant pembrolizumab and chemotherapy for locally advanced triple-negative breast cancer who developed cytokine release syndrome (CRS)/hemophagocytic lymphohistiocytosis (HLH). CRS/HLH secondary to pembrolizumab are scarcely documented in the literature and, to our knowledge, have never been reported in the context of neoadjuvant treatment for breast cancer.

Propofol regulates the progression of hepatocellular carcinoma via the POLR2L/TGF-β signaling pathway

Background

Hepatocellular carcinoma (HCC) is a malignant tumor with high morbidity and mortality. Propofol has been reported to modulate tumorigenesis in HCC; the aim of this study was to investigate the effect of the interaction of propofol with POLR2L on HCC tumor progression in HCC.

Methods

The propofol-related GSE101724 dataset was analyzed using weighted gene co-expression network analysis (WGCNA) and differentially expressed genes (DEGs) to identify overlapping genes. Key genes were selected from The Cancer Genome Atlas-liver hepatocellular carcinoma (TCGA-LIHC)-DEGs for prognostic analysis. The impact of POLR2L on LIHC patient survival was assessed, followed by in vitro experiments to validated its effects on HCC cell behavior and signaling pathways.

Results

Fourteen overlapping genes were identified in the turquoise module (highest correlation) of up-regulated DEGs and GSE101724. Further analysis obtained 11 key overlapping genes from 14 overlapping genes and TCGA-LIHC-DEGs, among which HSPE1 and POLR2L showed significant prognostic correlation. Patients with LIHC have a worse chance of surviving when their POLR2L expression is elevated. Knockdown POLR2L significantly inhibited the proliferation, invasion, and migration of HCC cell lines. Downregulation of POLR2L was accompanied by induced apoptosis, cell cycle arrest, and modulation of the expression of apoptosis-related genes. Propofol was found to downregulate POLR2L expression, inhibiting cell proliferation and growth. Further, it was shown that propofol controlled the development of HCC by influencing the POLR2L/TGF-β signaling loop.

Conclusions

The results validated the predictive relevance of POLR2L in HCC and emphasized that propofol can regulate HCC progression through the POLR2L/TGF-β signaling pathway.

Neutrophils and Anesthetic Drugs: Implications in Onco-Anesthesia

Apart from being a significant line of defense in the host defense system, neutrophils have many immunological functions. Although there are not many publications that accurately present the functions of neutrophils in relation to oncological pathology, their activity and implications have been studied a lot recently. This review aims to extensively describe neutrophils functions'; their clinical implications, especially in tumor pathology; the value of clinical markers related to neutrophils; and the implications of neutrophils in onco-anesthesia. This review also aims to describe current evidence on the influence of anesthetic drugs on neutrophils' functions and their potential influence on perioperative outcomes.

Herb-drug interactions: A short review on central and peripheral nervous system drugs

Herbal medicines are widely perceived as natural and safe remedies. However, their concomitant use with prescribed drugs is a common practice, often undertaken without full awareness of the potential risks and frequently without medical supervision. This practice introduces a tangible risk of herb-drug interactions, which can manifest as a spectrum of consequences, ranging from acute, self-limited reactions to unpredictable and potentially lethal scenarios. This review offers a comprehensive overview of herb-drug interactions, with a specific focus on medications targeting the Central and Peripheral Nervous Systems. Our work draws upon a broad range of evidence, encompassing preclinical data, animal studies, and clinical case reports. We delve into the intricate pharmacodynamics and pharmacokinetics underpinning each interaction, elucidating the mechanisms through which these interactions occur. One pressing issue that emerges from this analysis is the need for updated guidelines and sustained pharmacovigilance efforts. The topic of herb-drug interactions often escapes the attention of both consumers and healthcare professionals. To ensure patient safety and informed decision-making, it is imperative that we address this knowledge gap and establish a framework for continued monitoring and education. In conclusion, the use of herbal remedies alongside conventional medications is a practice replete with potential hazards. This review not only underscores the real and significant risks associated with herb-drug interactions but also underscores the necessity for greater awareness, research, and vigilant oversight in this often-overlooked domain of healthcare.

Attenuation of intestinal ischemia-reperfusion-injury by anesthetics: a potentially protective effect of anesthetic management in experimental studies

Intestinal ischemia-reperfusion injury (IRI) is a potentially severe clinical syndrome after major surgical procedures. In addition to causing intestinal mucosa injury, intestinal IRI further damages distant organs, causing the severity of the condition in patients. So far, effective therapy for intestinal IRI is still absent, and the survival rate of the patients is low. Previous experimental studies have shown that some anesthetics can alleviate intestinal IRI and protect organs while exerting their pharmacological effects, indicating that reasonable perioperative anesthesia management may provide potential benefits for patients to avoid intestinal IRI. These meaningful findings drive scholars to investigate the mechanism of anesthetics in treating intestinal IRI in-depth to discuss the possible new clinical uses. In the present mini-review, we will introduce the protective effects of different anesthetics in intestinal IRI to help us enrich our knowledge in this area.

Toll-Like Receptor 4 Deficiency Ameliorates Propofol-Induced Impairments of Cognitive Function and Synaptic Plasticity in Young Mice

Propofol is one of the most used intravenous anesthetic agents, which is widely used in clinical anesthesia induction and maintenance of pediatric patients. Exposure of the developing brain to propofol has been reported to lead to adverse brain changes, which in turn can induce persistent behavioral abnormalities in adulthood. However, the mechanisms by which propofol exposure in the developing brain induces cognitive impairment remain unclear. Here we report that repeated propofol exposure during the second postnatal week impairs spatial learning and memory in young mice. The reduced excitatory synaptic function and synaptogenesis in hippocampal CA1 neurons underlie this cognitive impairment. Propofol exposure specifically activates Toll-like receptor 4 (TLR4)-myeloid differentiation primary response protein 88 (MyD88)-NF-κB signaling pathway. TLR4 deficiency recues propofol exposure-induced synaptic function and cognitive deficits in young mice. Thus, we provide evidence that the activation of the TLR4-mediated pathway by propofol exposure may serve as a crucial trigger for the cognitive impairment in young adulthood caused by repeated exposure to propofol in the developing brain.

Impact on cerebral hemodynamics of the use of volume guarantee combined with high frequency oscillatory ventilation in a neonatal animal respiratory distress model

High-frequency oscillatory ventilation (HFOV) is an alternative to conventional mechanical ventilation (CMV). Recently, the use of volume guarantee (VG) combined with HFOV has been suggested as a safe strategy capable of reducing the damage induced by ventilation in immature lungs. However, the possible impact of this new ventilation technique on cerebral hemodynamics is unknown. To evaluate the cerebral hemodynamics effect of HFOV combined with VG in an experimental animal model of neonatal respiratory distress syndrome (RDS) due to surfactant deficiency compared with HFOV and CMV+VG (control group). Eighteen newborn piglets were randomized, before and after the induction of RDS by bronchoalveolar lavage, into 3 mechanical ventilation groups: CMV, HFOV and HFOV with VG. Changes in cerebral oxygen transport and consumption and cerebral blood flow were analyzed by non-invasive regional cerebral oxygen saturation (CrSO2), jugular venous saturation (SjO2), the calculated cerebral oxygen extraction fraction (COEF), the calculated cerebral fractional tissue oxygen extraction (cFTOE) and direct measurement of carotid artery flow. To analyze the temporal evolution of these variables, a mixed-effects linear regression model was constructed. After randomization, the following statistically significant results were found in every group: a drop in carotid artery flow: at a rate of -1.7 mL/kg/min (95% CI: -2.5 to -0.81; p < 0.001), CrSO2: at a rate of -6.2% (95% CI: -7.9 to -4.4; p < 0.001) and SjO2: at a rate of -20% (95% CI: -26 to -15; p < 0.001), accompanied by an increase in COEF: at a rate of 20% (95% CI: 15 to 26; p < 0.001) and cFTOE: at a rate of 0.07 (95% CI: 0.05 to 0.08; p < 0.001) in all groups. No statistically significant differences were found between the HFOV groups.

CONCLUSION

No differences were observed at cerebral hemodynamic between respiratory assistance in HFOV with and without VG, being the latter ventilatory strategy equally safe.

WHAT IS KNOWN

• Preterm have a situation of fragility of cerebral perfusion wich means that any mechanical ventilation strategy can have a significant influence. High-frequency oscillatory ventilation (HFOV) is an alternative to conventional mechanical ventilation (CMV). Recently, the use of volume guarantee (VG) combined with HFOV has been suggested as a safe strategy capable of reducing the damage induced by ventilation in immature lungs. Several studies have compared CMV and HFOV and their effects at hemodynamic level. It is known that the use of high mean airway pressure in HFOV can cause an increase in pulmonary vascular resistance with a decrease in thoracic venous return.

WHAT IS NEW

• The possible impact of VAFO + VG on cerebral hemodynamics is unknown. Due the lack of studies and the existing controversy, we have carried out this research project in an experimental animal model with the aim of evaluating the cerebral hemodynamic repercussion of the use of VG in HFOV compared to the classic strategy without VG.

Different Sedation Strategies in Older Patients Receiving Spinal Anesthesia for Hip Surgery on Postoperative Delirium: A Randomized Clinical Trial

Background

Postoperative delirium (POD) is of great concern as a complication of surgery in older adult patients. Sedation strategies influence the development of POD. This study compared how sedation strategies administered during spinal anesthesia influenced POD in patients aged ≥65 years undergoing elective surgery for hip fracture repair.

Patients and Methods

A randomized clinical trial was conducted from 1 August 2021 to 30 June 2022 at a single academic medical center. Two hundred and twenty-six patients were randomly divided into four groups: lighter sedation with propofol (LP), heavier sedation with propofol (HP), lighter sedation with dexmedetomidine (LD), and heavier sedation with dexmedetomidine (HD). The incidence of delirium was the primary outcome and was assessed daily by the blinded Confusion Assessment Method.

Results

There was a significant association between dexmedetomidine (LD+HD group) and a lower incidence of delirium (11.9% [13/109] vs the propofol group (23.6% [26/110]; Risk ratio, 0.51; 95% CI, 0.274 to 0.929; p=0.024). In the propofol group, heavier sedation had a higher rate of POD (32.7% [18/55] vs the lighter sedation group (14.5% [8/55]; Risk ratio, 2.25; 95% CI, 1.069 to 4.736; p=0.025).

Conclusion

Dexmedetomidine was associated with a lower incidence of delirium than that with propofol among older patients with hip fractures. In patients that received propofol, heavier sedation was associated with high incidence of POD.

Comparison of Fat-Free Mass and Ideal Body Weight Scalar for Anesthetic Induction Dose of Propofol in Patients with Morbid Obesity: A Double-Blind, Randomized Clinical Trial

Background

Obesity is a growing problem worldwide and can affect both the pharmacodynamics and pharmacokinetics of various drugs, including anesthetics, resulting in the under-or overdosing of certain drugs. There is no consensus on the ideal dosing regimen for obese populations.

Objectives

In this study, 2 weight-based dosing of propofol used for induction of anesthesia were compared in terms of the onset of action time, adequacy of anesthesia, and effects on hemodynamic indices (eg, heart rate [HR] and blood pressure).

Methods

In this randomized, double-blind clinical trial, 40 patients with morbid obesity (MO) scheduled for bariatric surgery with body mass index (BMI) > 35, age 18 - 59 years, American Society of Anesthesiologists physical status (ASA-PS) II and III were randomly divided into 2 groups, using block randomization method, to receive 2 mg/kg of propofol for induction of anesthesia based on either fat-free mass (FFM) group or ideal body weight (IBW) group. The primary outcome was the time duration to reach the bispectral index (BIS) ≤ 60. Time to the disappearance of eyelash reflex, signs of inadequate anesthesia (ie, BIS > 60, straining during intubation, or eye-opening), requirements for additional doses, and hemodynamic indices (including HR and mean arterial pressure [MAP]) were also compared.

Results

The mean time to reach BIS ≤ 60 was 134.1 s in the FFM group and 148.7 s in the IBW group. This difference was not statistically significant (P = 0.334). The time of disappearance of eyelash reflex was also not significantly different between the study groups (P = 0.814). However, 2 patients in the FFM group and 8 patients in the IBW group showed signs of inadequate anesthesia and required additional doses. This difference was statistically significant (P = 0.032). Hemodynamic variables, before and 2 min after propofol induction dose administration were comparable between the study groups (P = 0.520, P = 0.327, P = 0.847, P = 0.516 for pre-intervention MAP, post-intervention MAP, pre-intervention HR, and post-intervention HR, respectively).

Conclusions

Propofol dosing, based on FFM and IBW, for induction of anesthesia, provides comparable onset time of action and hemodynamic effects; however, in terms of the adequacy of anesthesia, the dosing based on FFM is more favorable compared to the dosing based on IBW.

Propofol-Related Infusion Syndrome in a Child With Refractory Status Epilepticus: Successful Resuscitation With Veno-Arterial Extracorporeal Membrane Oxygenation, Continuous Renal Replacement Therapy, and Therapeutic Plasma Exchange

Propofol is used for sedation, anxiolysis, anesthesia induction, and as an anticonvulsant. In cases of refractory status epilepticus (RSE), propofol is more efficient than barbiturates. We present a case of a 3-year-old female with RSE who developed propofol-related infusion syndrome (PRIS) despite low dosage after failed attempts with multiple anti-epileptic drips and bolus therapies. Careful consideration must be made before initiating propofol administration for RSE. We discuss our PRIS treatment approach with extracorporeal membrane oxygenation, therapeutic plasma exchange, and continuous renal replacement therapy leading to our patient recovering to baseline and being discharged home from the hospital.

Successful management of suspected propofol dependence with phenobarbital in an adult patient with COVID-19

PURPOSE

In critically ill patients, high sedation requirements for prolonged durations are often needed to achieve ventilator synchrony, a practice that was particularly common during the early stages of the coronavirus disease 2019 (COVID-19) pandemic. We report the successful use of phenobarbital to facilitate propofol weaning after prolonged medication exposure.

SUMMARY

A 64-year-old male with hypertension was admitted for the management of acute respiratory distress syndrome due to COVID-19 pneumonia. The patient received high doses of fentanyl and propofol with periods of concomitant midazolam and dexmedetomidine throughout his prolonged time on mechanical ventilation. Total days of exposure were 19 for fentanyl, 17 for propofol, 12 for midazolam, and 15 for dexmedetomidine. Upon improvement in lung function, attempts to wean the patient from propofol all failed due to symptoms such as tachypnea, tachycardia, and hypertension, with symptom resolution only upon return to the previous dose. Phenobarbital was trialed for possible propofol withdrawal syndrome, allowing for a dose reduction of 10 μg/kg/min within 2 hours of the first dose without any corresponding symptoms. The patient continued to receive intermittent doses of phenobarbital for another 36 hours until propofol was discontinued. He underwent tracheostomy shortly after weaning off all sedation and was discharged to rehab 34 days after his initial admission.

CONCLUSION

Information concerning propofol withdrawal syndrome in the literature is limited. Our experience demonstrates the successful use of phenobarbital to facilitate propofol weaning after prolonged exposure.

C60 adduct with L-arginine as a promising nanomaterial for treating cerebral ischemic stroke

The work aimed to investigate the biocompatibility and biological activity of the water-soluble fullerene adduct C60-Arg. It was found that the material is haemocompatible, is not cyto- and genotoxic, possesses pronounced antioxidant activity. Additionally, this paper outlines the direction of application of water-soluble fullerene adducts in the creation of neuroprotectors. It has been suggested that a putative mechanism of the protective action of the C60-Arg adduct is associated with its antioxidant properties, the ability to penetrate the blood-brain barrier, and release nitrogen monoxide as a result of the catabolism of L-arginine residues, which promote vascular relaxation. The action of the C60-Arg adduct was compared with the action of such an antioxidant as Edaravone, which is approved in Japan for the treatment of ischemic and haemorrhagic strokes.

Oxygen saturation profile in traumatic brain injury animal model after propofol administration

Traumatic brain injury (TBI) is a traumatic that often leads to death due to untreatable cerebral hypoxia, indicated by oxygen saturation of <90%. Cerebral hypoxia is rarely monitored and thereby often overlooked as a cause of mortality and monitoring oxygen saturation is an accurate method to detect the condition. Propofol, an anesthetic agent, is commonly used in the management of TBI; however, its effect on brain tissue and cerebral hypoxia in TBI cases is not well understood. The aim of this study was to evaluate the profile of oxygen saturation in TBI animal model after propofol administration. A laboratory experimental study was conducted, involving 18 male Rattus novergicus rats (aged 4-8 weeks with weight between 150-200 grams) divided into three different treatment groups (non-TBI, TBI without propofol, and TBI with propofol). Oxygen saturation was measured regularly from day 1 to day 8 using pulse oximetry. The oxygen saturation percentages were compared between the TBI rats with and without propofol administration using independent Student t-rest. The results revealed significant reductions of oxygen saturation levels of animals within propofol-treated TBI group compared to that of the untreated-TBI group (p<0.05), with the average oxygen saturation ranging from 80.8%±6.96% vs 86.8%±5.48%. This finding suggests a reducing effect of propofol administration on oxygen saturation levels in rats with TBI and this potentially causes cerebral hypoxia.

Two Cases of Inadequate Response to Remimazolam

We report the inadequate efficacy of remimazolam in two patients undergoing long-term benzodiazepine analog therapy. Remimazolam is a recently developed ultrashort-acting benzodiazepine. It is primarily used as an anesthetic in surgical procedures, as it has minimal effect on cardiac function and antagonists are available. It is expected to become more widely used in the future. On the other hand, similar to other benzodiazepines, benzodiazepine tolerance can also pose a challenge with remimazolam. Herein, we report two cases who were taking long-term oral benzodiazepine analogs. One patient did not fall asleep despite a sufficient dose of remimazolam and required a change to propofol. The other patient required a high dose of remimazolam to fall asleep; however, multiple signs of arousal were noted intraoperatively. Our findings suggest that remimazolam may not be an ideal anesthetic in long-term benzodiazepine analog users. Comprehensive assessment of preoperative medications and careful monitoring of intraoperative sedation levels are necessary. Furthermore, it may be advisable to consider the use of alternative agents such as propofol.

A retrospect and outlook on the neuroprotective effects of anesthetics in the era of endovascular therapy

Studies on the neuroprotective effects of anesthetics were carried out more than half a century ago. Subsequently, many cell and animal experiments attempted to verify the findings. However, in clinical trials, the neuroprotective effects of anesthetics were not observed. These contradictory results suggest a mismatch between basic research and clinical trials. The Stroke Therapy Academic Industry Roundtable X (STAIR) proposed that the emergence of endovascular thrombectomy (EVT) would provide a proper platform to verify the neuroprotective effects of anesthetics because the haemodynamics of patients undergoing EVT is very close to the ischaemia–reperfusion model in basic research. With the widespread use of EVT, it is necessary for us to re-examine the neuroprotective effects of anesthetics to guide the use of anesthetics during EVT because the choice of anesthesia is still based on team experience without definite guidelines. In this paper, we describe the research status of anesthesia in EVT and summarize the neuroprotective mechanisms of some anesthetics. Then, we focus on the contradictory results between clinical trials and basic research and discuss the causes. Finally, we provide an outlook on the neuroprotective effects of anesthetics in the era of endovascular therapy.

Propofol anesthesia-induced spatiotemporal changes in cortical activity with loss of external and internal awareness: An electrocorticography study

OBJECTIVE

To understand the underlying mechanism of consciousness, investigating spatiotemporal changes in the cortical activity during the induction phase of unconsciousness is important. Loss of consciousness induced by general anesthesia is not necessarily accompanied by a uniform inhibition of all cortical activities. We hypothesized that cortical regions involved in internal awareness would be suppressed after disruption of cortical regions involved in external awareness. Thus, we investigated temporal changes in cortex during induction of unconsciousness.

METHODS

We recorded electrocorticography data of 16 epilepsy patients and investigated power spectral changes during induction phase from awake state to unconsciousness. Temporal changes were assessed at 1) the start point and 2) the interval of normalized time between start and end of power change (Δ t^normalized).

RESULTS

We found that the power increased at frequencies < 46 Hz, and decreased in range of 62-150 Hz, in global channels. In temporal changes of power change, superior parietal lobule and dorsolateral prefrontal cortex started to change early, but the changes were completed over a prolonged interval, whereas angular gyrus and associative visual cortex showed a delayed change and rapid completion.

CONCLUSIONS

Loss of consciousness induced by general anesthesia results first from disrupted communication between self and external world, followed by disrupted communication within self, with decreased activities of superior parietal lobule and dorsolateral prefrontal cortex, and later, attenuated activities of angular gyrus.

SIGNIFICANCE

Our findings provided neurophysiological evidence for the temporal changes in consciousness components induced by general anesthesia.

Anesthesia and developing brain: What have we learned from recent studies

Anesthesia is unavoidable in surgical procedures. However, whether the general anesthetics are neurotoxic to immature brains remains undefined. Neurodevelopmental impairment induced by anesthesia has been a critical health issue and topic of concern. This review summarizes recent progress made in clinical and preclinical studies to provide useful suggestions and potential therapeutic targets for the protection of the immature brain. On the one hand, clinical researchers continue the debate about the effect of single and multiple exposures to anesthesia on developing brains. On the other hand, preclinical researchers focus on exploring the mechanisms of neurotoxic effects of general anesthesia on immature brains and seeking novel solutions. Rodent models have always been used in preclinical studies, but it is still unclear whether the mechanisms observed in rodent models have clinical relevance. Compared with these models, non-human primates (NHPs) are more genetically similar to humans. However, few research institutions in this area can afford to use NHP models in their studies. One way to address both problems is by combining single-cell sequencing technologies to screen differential gene expression in NHPs and perform in vivo validation in rodents. The mechanism of anesthesia-induced neurotoxicity still requires further elucidation in primates.

Propofol attenuates kinesin-mediated axonal vesicle transport and fusion

Propofol is a widely used general anesthetic, yet the understanding of its cellular effects is fragmentary. General anesthetics are not as innocuous as once believed and have a wide range of molecular targets that include kinesin motors. Propofol, ketamine, and etomidate reduce the distances that Kinesin-1 KIF5 and Kinesin-2 KIF3 travel along microtubules in vitro. These transport kinesins are highly expressed in the CNS, and their dysfunction leads to a range of human pathologies including neurodevelopmental and neurodegenerative diseases. While in vitro data suggest that general anesthetics may disrupt kinesin transport in neurons, this hypothesis remains untested. Here we find that propofol treatment of hippocampal neurons decreased vesicle transport mediated by Kinesin-1 KIF5 and Kinesin-3 KIF1A ∼25-60%. Propofol treatment delayed delivery of the KIF5 cargo NgCAM to the distal axon. Because KIF1A participates in axonal transport of presynaptic vesicles, we tested whether prolonged propofol treatment affects synaptic vesicle fusion mediated by VAMP2. The data show that propofol-induced transport delay causes a significant decrease in vesicle fusion in distal axons. These results are the first to link a propofol-induced delay in neuronal trafficking to a decrease in axonal vesicle fusion, which may alter physiological function during and after anesthesia.

Propofol-Related Infusion Syndrome: A Clinical Review

Propofol-related infusion syndrome (PRIS) is a lethal condition characterized by multiple organ system failures. It can occur due to prolonged administration of propofol (an anesthetic) in mechanically intubated patients. The main presenting features of this condition include cardiovascular dysfunction with particular emphasis on impairment of cardiovascular contractility, metabolic acidosis, lactic acidosis, rhabdomyolysis, hyperkalaemia, lipidaemia, hepatomegaly, acute renal failure, and eventually mortality in most cases. The significant risk factors that predispose one to PRIS are: critical illnesses, increased serum catecholamines, steroid therapy, obesity, young age (significantly below three years), depleted carbohydrate stores in the body, increased serum lipids, and most importantly, heavy or extended dosage of propofol. The primary pathophysiology behind PRIS is the disruption of the mitochondrial respiratory chain that causes inhibition of adenosine triphosphate (ATP) synthesis and cellular hypoxia. Further, excess lipolysis of adipose tissue occurs, especially in critically ill patients where the energy source is lipid breakdown instead of carbohydrates. This process generates excess free fatty acids (FFAs) that cannot undergo adequate beta-oxidation. These FFAs contribute to the clinical pathology of PRIS. It requires prompt management as it is a fatal condition. The clinicians must observe the patient's electrocardiogram (ECG), serum creatine kinase, lipase, amylase, lactate, liver enzymes, and myoglobin levels in urine, under propofol sedation. Doctors should immediately stop propofol infusion upon noticing any abnormality in these parameters. The other essentials of management of various manifestations of PRIS will be discussed in this article, along with a detailed explanation of the condition, its risk factors, diagnosis, pathophysiology, and presenting features. This article aims to make clinicians more aware of the occurrence of this syndrome so that better ways to manage and treat this condition can be formulated in the future.

Focus on long non-coding RNA MALAT1: Insights into acute and chronic lung diseases

Acute lung injury (ALI) is a pulmonary illness with a high burden of morbidity and mortality around the world. Chronic lung diseases also represent life-threatening situations. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a type of long non-coding RNA (lncRNA) and is highly abundant in lung tissues. MALAT1 can function as a competitive endogenous RNA (ceRNA) to impair the microRNA (miRNA) inhibition on targeted messenger RNAs (mRNAs). In this review, we summarized that MALAT1 mainly participates in pulmonary cell biology and lung inflammation. Therefore, MALAT1 can positively or negatively regulate ALI and chronic lung diseases (e.g., chronic obstructive pulmonary disease (COPD), bronchopulmonary dysplasia (BPD), pulmonary fibrosis, asthma, and pulmonary hypertension (PH)). Besides, we also found a MALAT1-miRNA-mRNA ceRNA regulatory network in acute and chronic lung diseases. Through this review, we hope to cast light on the regulatory mechanisms of MALAT1 in ALI and chronic lung disease and provide a promising approach for lung disease treatment.

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.

Pre-procedural Preparation and Sedation for Gastrointestinal Endoscopy in Patients with Advanced Liver Disease

Gastrointestinal endoscopy in patients with advanced liver disease poses various challenges, a major one being procedural sedation and its associated considerations. While sedation during endoscopy can improve patient comfort, decrease anxiety, and facilitate procedural completion, in patients with advanced liver disease, it is also associated with substantial and unique risks due to alterations in drug metabolism and other factors. As such, the choice of sedative agent(s) and related logistics may require careful inter-disciplinary planning and individualized considerations. Furthermore, a large proportion of agents require dose reductions and particular monitoring of the vital signs, level of consciousness, and other indices. In the present review, we provide a contemporary overview of procedural sedation considerations, commonly used intravenous sedatives, and second-line as well as novel sedatives for gastrointestinal endoscopy in patients with advanced liver disease.

Effects of general anesthesia on behavioral circadian rhythms and clock-gene expression in the suprachiasmatic nucleus in rats

The suprachiasmatic nucleus (SCN) of the hypothalamus is a nucleus that regulates circadian rhythms through the cyclic expression of clock genes. It has been suggested that circadian-rhythm-related, adverse postoperative events, including sleep disturbances and delirium, are partly caused by anesthesia-induced disruption of clock-gene expression. We examined the effects of multiple general anesthetics on the expression cycle of Period2 (Per2), one of the clock genes that regulate circadian rhythms in the SCN, and on the behavioral rhythms of animals. Rats were treated with sevoflurane, propofol, and dexmedetomidine for 4 h. The expression of Per2 in SCN was analyzed using in situ hybridization, and the behavioral rhythm before and after anesthesia was analyzed. Per2 expression in the SCN decreased significantly immediately after anesthesia in all groups compared with corresponding control groups. However, Per2 returned to normal levels within 24 h, and there was no phase change in the gene expression cycle or behavioral rhythm. This study suggests that acute suppression of Per2 expression may be a general phenomenon induced by general anesthesia, but that the molecular mechanism of the body clock is resilient to disturbances to some extent.

Efficacy of Sumatriptan/Placebo versus Sumatriptan/Propofol Combination in Acute Migraine; a Randomized Clinical Trial

Introduction

Migraine headaches can cause severe pain for patients and lead them to multiple visits to the emergency department (ED). This study aimed to evaluate the efficacy of propofol + sumatriptan combination in comparison with sumatriptan alone in the management of acute migraine headaches.

Methods

This triple-blind clinical trial involved patients who referred to two emergency departments with acute migraine headaches. Patients were randomly assigned to control (sumatriptan and placebo) or intervention (propofol and sumatriptan) groups for comparison of the efficacy and side effects of treatment.

Results

In this study, 60 patients were included whose mean age was 31±8.8 years, and headaches were more common among women. After 30 and 60 minutes from the beginning of treatment, the mean pain score reduction in the intervention group was significantly greater than that in the control group (p=0.012, p=0.024). In addition, the rate of chest tightness in the control group was significantly higher than the intervention group. The absolute risk reduction of adverse events (Chest tightness, Bradycardia, hypotension, and etc.), in patients with acute migraine headache taking propofol and sumatriptan treatment, was 32.18% (95% CI: 8.02 - 56.35).

Conclusions

This study supports the use of propofol for treatment of acute migraine headaches and shows that combining sumatriptan with propofol is more effective in relieving migraine headaches and the associated symptoms than using sumatriptan alone. However, more studies with longer follow-ups are still needed.

Effects of propofol on neuroblastoma cells via the HOTAIRM1/miR-519a-3p axis

Background

Propofol, an intravenous sedative-hypnotic agent, is demonstrated to have antioxidant properties. The purpose of this study is to investigate the functional roles of propofol in neuroblastoma cells.

Methods

The proliferation and apoptosis were assessed by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide (MTT), EdU, and flow cytometry assays, respectively. The protein expression level was quantified by western blot assay. Inflammation and oxidative stress were determined by measuring the release of inflammatory factors, along with intracellular reactive oxygen species (ROS), lactate dehydrogenase (LDH), malondialdehyde (MDA), and superoxide dismutase (SOD) levels. The real-time quantitative polymerase chain reaction (RT-qPCR) was conducted to assess the expression levels of HOXA transcript antisense RNA, myeloid-specific 1 (HOTAIRM1), and miR-519a-3p in cells. The interaction relationship between HOTAIRM1 and miR-519a-3p was confirmed by dual-luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays.

Results

Treatment with MPP⁺ has been observed to induce apoptosis, oxidative stress, and inflammation in neuroblastoma cells, which were abolished by propofol or silencing of HOTAIRM1. Importantly, the increase of HOTAIRM1 and the decrease of miR-519a-3p caused by MPP⁺ were reversed by propofol in neuroblastoma cells. In addition, miR-519a-3p was a target of HOTAIRM1, and inhibition of miR-519a-3p abolished HOTAIRM1 silencing-induced effects on neuroblastoma cells. Moreover, functional experiments revealed that propofol might weaken MPP⁺-induced apoptosis, oxidative stress, and inflammation by regulating the HOTAIRM1/miR-519a-3p axis.

Conclusion

Propofol inhibited oxidative stress and inflammation in MPP⁺-induced neuroblastoma cells by targeting the HOTAIRM1/miR-519a-3p axis, implying the potential protective function of propofol against oxidative damage.

An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery

Postoperative cognitive dysfunction is extremely prevalent following cardiac surgery. The increasing patient age and comorbidity profile increases their susceptibility to cognitive impairment. The underlying pathophysiological mechanisms leading to cognitive impairment are not clearly elucidated. Using the contemporary literature (2015-present), this narrative review has three aims. Firstly, to provide an overview of postoperative cognitive impairment. Secondly, to analyse the predominant pathophysiological mechanisms leading to cognitive dysfunction following cardiac surgery such as inflammation, cerebral hypoperfusion, cerebral microemboli, glycaemic control and anaesthesia induced neurotoxicity. Lastly, to assess the current therapeutic strategies of interest to address these pathophysiological mechanisms, including the administration of dexamethasone, the prevention of prolonged cerebral desaturations and the monitoring of cerebral perfusion using near-infrared spectroscopy, surgical management strategies to reduce the neurological effects of microemboli, intraoperative glycaemic control strategies, the effect of volatile vs. intravenous anaesthesia, and the efficacy of dexmedetomidine.

Assessing the Antioxidant Activity of Dexmedetomidine by Measuring the Plasma Antioxidant Enzyme Activity of Catalase, Glutathione Peroxidase, and Superoxide Dismutase During Lumbar Spine Laminectomy

Background: Current knowledge on antioxidant properties of anesthetics is inconclusive. Nevertheless, experiments on different anesthesia-related drugs and techniques are growing. Objectives: The aim of this prospective blinded randomized study was to assess the effect of dexmedetomidine (Dex) infusion during anesthesia on oxidative stress resulting from lumbar laminectomy. Methods: The antioxidant activity of Dex compared to placebo (normal saline) was evaluated by measuring the antioxidant enzyme activity of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX). A total of 56 patients who underwent laminectomy surgery were allocated into two groups of intervention and control. Dex group received 0.6 µg.kg-1 dexmedetomidine infusion before induction of anesthesia over 15 minutes, followed by 0.4 µg.kg-1.hr-1 maintenance. Control group received the same volume and sequence of normal saline. Anesthesia protocol was similar in both groups. The antioxidant activity of the previously mentioned enzymes was measured at the beginning of the anesthesia (T1) and after surgery (T2). Propofol consumption, hemodynamic indices, shivering, bleeding volume, and pain numeric rating scale (NRS) were recorded. Results: Although the serum levels of CAT and GPX increased during the procedure, these changes were not significant (P-values 0.579 and 0.762, respectively). Also, the mean SOD level did not change over time in any of the groups, and it was not meaningfully different between the groups at any of the predetermined times (P-value 0.665). Conclusions: As expected, Dex decreased propofol consumption, mean heart rate, mean arterial pressure, and pain intensity allover the perioperative period. It seems that adding Dex to anesthesia regimen during laminectomy had no dominant antioxidant effects.

Propofol and Sevoflurane Anesthesia in Early Childhood Do Not Influence Seizure Threshold in Adult Rats

Experimental studies have demonstrated that general anesthetics administered during the period of synaptogenesis may induce widespread neurodegeneration, which results in permanent cognitive and behavioral deficits. What remains to be elucidated is the extent of the potential influence of the commonly used hypnotics on comorbidities including epilepsy, which may have resulted from increased neurodegeneration during synaptogenesis. This study aimed to test the hypothesis that neuropathological changes induced by anesthetics during synaptogenesis may lead to changes in the seizure threshold during adulthood. Wistar rat pups were treated with propofol, sevoflurane, or saline on the sixth postnatal day. The long-term effects of prolonged propofol and sevoflurane anesthesia on epileptogenesis were assessed using corneal kindling, pilocarpine-, and pentylenetetrazole-induced seizure models in adult animals. Body weight gain was measured throughout the experiment. No changes in the seizure threshold were observed in the three models. A significant weight gain after exposure to anesthetics during synaptogenesis was observed in the propofol group but not in the sevoflurane group. The results suggest that single prolonged exposure to sevoflurane or propofol during synaptogenesis may have no undesirable effects on epileptogenesis in adulthood.

The serotonin toxidrome: shortfalls of current diagnostic criteria for related syndromes

INTRODUCTION

Serotonin syndrome (toxicity) describes adverse drug effects from toxic amounts of intra-synaptic central nervous system serotonin. A wide range of drugs have been implicated to cause serotonin toxicity, not all justifiably. The plausible agents all have a final common pathway resulting in a substantial increase in central nervous system serotonergic neurotransmission. Serotonin toxicity is characterized by neuromuscular excitation, mental status changes, and autonomic dysregulation. Signs and symptoms represent a spectrum of toxicity (mild to life-threatening) related to increasing serotonin concentrations. As there is no consensus on the threshold for "toxicity" or diagnostic criteria, the true incidence of serotonin toxicity is unknown. The incidence in overdose is easier to quantify and is reasonably common in serotonergic antidepressant overdoses. In a large case series of overdoses, moderate serotonin toxicity occurred in 14% of poisonings with a selective serotonin reuptake inhibitor. While half those ingesting a monoamine oxidase inhibitor in combination with a serotonergic agent in overdose exhibit at least moderately severe serotonin toxicity. In contrast, the incidence of serotonin toxicity in those on therapeutic serotonergic agents appears to be very low.

OBJECTIVES

To provide a narrative review of the current diagnostic criteria, utilizing case reports of fatalities to evaluate how many meet the various diagnostic criteria and propose practical solutions to resolve controversies in diagnosis.

METHODS

A review of serotonin toxicity diagnostic criteria in the English literature was completed by searching Embase and PubMed from January 1990 to July 2021 for the keywords "serotonin syndrome/toxicity" paired with "diagnostic criteria" or "diagnosis." Also, fatal cases of serotonin toxicity identified from a recent systematic review were independently examined to determine what diagnostic criteria were met and whether serotonin toxicity or another cause was most likely.

REVIEW OF DIAGNOSIS CRITERIA

Serotonin toxicity is a clinical diagnosis, four diagnostic criteria (Sternbach, Serotonin Syndrome Scale, Radomski, and Hunter) have been proposed. However, the Serotonin Syndrome Scale has not been validated in patients with serotonin toxicity and only utilized in those on a serotonergic agent. The remaining three criteria are utilized more widely but have undergone little refinement or validation.

REVIEW OF FATAL CASES

Shortfalls with diagnostic criteria can be illustrated by examining case fatalities. Of 55 fatal cases reviewed, 12 (22%) were unlikely to be serotonin toxicity. Sternbach and Radomski criteria were met by 25 (45%), 20 (36%) had insufficient data reported and 10 (18%) met an exclusion criterion. Few had sufficient information reported to determine whether Hunter Criteria were met, with only 13 (24%) documented as meeting the criteria, the remaining 42 (76%) had insufficient data.

RESOLVING SHORTFALLS IN CURRENT DIAGNOSTIC CRITERIA

As serotonin toxicity is a clinical diagnosis, issues arise when basing the diagnosis on symptom criteria alone, without considering whether the drug/s ingested increase central nervous system serotonin or whether there is an alternative diagnosis. This has resulted in case reports and government warnings for drugs that cannot plausibly cause significant serotonin toxicity (e.g., ondansetron and antipsychotics). We propose when assessing for a serotonin toxidrome, both the causative agent(s) and clinical scenario is considered to determine the likelihood of serotonin toxicity. Then the clinical features assessed, those with a moderate to high prior probability (e.g., serotonergic drug-drug interaction, overdose, recent initiation or increase in dose of serotonergic agent/s) could be diagnosed based on the Hunter criteria. However, those with a low probability (e.g., stable therapeutic doses of a serotonergic agent) require more specific and stringent criteria. Finally, we propose a minimum dataset for case reports/series of serotonin toxicity.

CONCLUSIONS

More complete and accurate reporting of serotonin toxicity cases is required in the future, to avoid further misleading associations that are physiologically implausible.

The Effects of Gene Variations of GABRA2, GABRB1, GABRG2, GAD1 and SLC1A3 on Patients with Propofol During Anesthesia Induction

Purpose

Propofol is one of the most commonly used intravenous sedatives in general anesthesia, while the individual variations of propofol are apparent. The objective of this study was to investigate the influence of genetic variations in GABAergic neurons and glutamatergic neurons on time to loss of consciousness (LOC) and the incidence of hypotension during anesthesia induction.

Patients and Methods

A total of 140 Chinese patients undergoing thyroid surgery or breast surgery were recruited. Genotyping of candidate genes was carried out using the Agena Bioscience MassARRAY system. Anesthesia induction was initiated with a propofol target plasma concentration (Cp) of 4.0 μg mL⁻¹. The LOC latency, systolic blood pressure, diastolic blood pressure, mean arterial pressure were documented.

Results

We found that GABRA2 rs35496835, GABRB1 rs1372496, GABRG2 rs11135176, GABRG2 rs209358, GAD1 rs3791878, SLC1A3 rs1049522 and gender were significant determinants of the patient’s LOC latency following propofol administration. GABRA2 rs11503014 was highly correlated with blood pressure reduction during anesthesia induction. Multiple linear regression analysis revealed that GABRB1 rs1372496, GABRG2 rs11135176, and SLC1A3 rs1049522 accounted for 35.3% variations in LOC latency following propofol administration.

Conclusion

Our findings indicate that genetic variants of GABRA2, GABRB1, GABRG2, GAD1 and SLC1A3 may have influence on propofol susceptibility, which would be an important guidance towards building clinical models that can precisely predict the efficacy of propofol with various populations before surgery.

Effects of N-Methyl-D-aspartate receptor (NMDAR) and Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα) on learning and memory impairment in depressed rats with different charge by modified electroconvulsive shock

Background

With the development of modified electroshock therapy (MECT), it has become necessary to increase the electric quantity in order to achieve a good antidepressant effect, but this increase will lead to more serious learning and memory impairment. The purpose of this study was to investigate the intrinsic mechanism of cognitive impairment induced by high-energy electroconvulsive shock (MECS, an animal model of MECT).

Methods

Rats were randomly divided into 6 groups: control (C, n=6), M0, M60, M120, M180, and M240 groups (MECS at 0, 60, 120, 180, and 240 mC stimulation intensity after 80 mg/kg propofol, with 12 rats in each group). Their depression-like behavior and learning and memory ability were evaluated by sucrose preference test (SPT), open field test (OFT), and Morris water maze test (MWM). The expression of phospho-NMDA receptor 1 (GluN1), GluN2A, GluN2B, Ca²⁺/calmodulin-dependent protein kinase IIα (CaMKIIα), p-T305-CaMKII, and postsynaptic densities-95 (PSD-95) in hippocampus were detected by western blot. The co-expression of CaMKIIα and GluN2B subunit was detected by co-immunoprecipitation (CO-IP).

Results

The chronic unpredictable mild stresses (CUMS) procedure successfully induced depression-like behavior in rats, which was improved in varying degrees after MECS. The results showed that the expression of GluN1, GluN2A, GluN2B, and PSD-95 decreased with the increase of charge, while p-T305-CaMKII increased, which led to the deterioration of learning and memory ability, but the expression change of CaMKIIα was not statistically significant.

Conclusions

Increase in the MECS charge adjusts the synaptic plasticity by changing the binding amount of CaMKIIα and its subunit GluN2B and the level of CaMKII autophosphorylation, thereby impairing learning and memory functions.

The central nervous system during lung injury and mechanical ventilation: a narrative review

Mechanical ventilation induces a number of systemic responses for which the brain plays an essential role. During the last decade, substantial evidence has emerged showing that the brain modifies pulmonary responses to physical and biological stimuli by various mechanisms, including the modulation of neuroinflammatory reflexes and the onset of abnormal breathing patterns. Afferent signals and circulating factors from injured peripheral tissues, including the lung, can induce neuronal reprogramming, potentially contributing to neurocognitive dysfunction and psychological alterations seen in critically ill patients. These impairments are ubiquitous in the presence of positive pressure ventilation. This narrative review summarises current evidence of lung-brain crosstalk in patients receiving mechanical ventilation and describes the clinical implications of this crosstalk. Further, it proposes directions for future research ranging from identifying mechanisms of multiorgan failure to mitigating long-term sequelae after critical illness.

Propofol for Induction and Maintenance of Anesthesia in Patients With Brugada Syndrome: A Single-Center, 25-Year, Retrospective Cohort Analysis

BACKGROUND

Propofol administration in patients with Brugada syndrome (BrS) is still a matter of debate. Despite lacking evidence for its feared arrhythmogenicity, up to date, expert cardiologists recommend avoiding propofol. The main aim of this study is to assess the occurrence of malignant arrhythmias or defibrillations in patients with BrS, during and 30 days after propofol administration. The secondary aim is to investigate the occurrence of adverse events during propofol administration and hospitalization, as the 30-day readmission and 30-day mortality rate.

METHODS

We performed a retrospective cohort study on patients with BrS who received propofol anytime from January 1, 1996 to September 30, 2020. Anesthesia was induced by propofol in both groups. In the total intravenous anesthesia (TIVA) group, anesthesia was maintained by propofol, while in the BOLUS group, volatile anesthesia was provided. The individual anesthetic charts and the full electronic medical records up to 30 postprocedural days were scrutinized.

RESULTS

One hundred thirty-five BrS patients who underwent a total of 304 procedures were analyzed. The TIVA group included 27 patients for 33 procedures, and the BOLUS group included 108 patients for 271 procedures. In the TIVA group, the median time of propofol infusion was 60 minutes (interquartile range [IQR] = 30-180). The estimated plasma or effect-site concentration ranged between 1.0 and 6.0 µg·mL-1 for target-controlled infusion (TCI). The infusion rate for manually driven TIVA varied between 0.8 and 10.0 mg·kg-1·h-1. In the BOLUS group, the mean propofol dose per kilogram total body weight was 2.4 ± 0.9 mg·kg-1. No malignant arrhythmias or defibrillations were registered in both groups. The estimated 95% confidence interval (CI) of the risk for malignant arrhythmias in the BOLUS and TIVA groups was 0-0.011 and 0-0.091, respectively.

CONCLUSIONS

The analysis of 304 anesthetic procedures in BrS patients, who received propofol, either as a TIVA or as a bolus during induction of volatile-based anesthesia, revealed no evidence of malignant arrhythmias or defibrillations. The present data do not support an increased risk with propofol-based TIVA compared to propofol-induced volatile anesthesia. Prospective studies are needed to investigate the electrophysiologic effects of propofol in BrS patents.

Propofol alleviates neuropathic pain in chronic constriction injury rat models via the microRNA-140-3p/Jagged-1 peptide/Notch signaling pathway

Chronic constriction injury (CCI) of the sciatic nerve was used to establish neuropathic pain (NP) models in rats. CCI rats were then treated with propofol (Pro) and their paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were measured. In addition, the expression patterns of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-10 were detected. CCI rats treated with propofol were further injected with antagomiR-140-3p to verify the role of miR-140-3p in propofol's analgesic actions. In addition to confirming the relationship between miR-140-3p and JAG1, the expression patterns of JAG1 itself were detected. Propofol-treated CCI rats were also injected with Ad-JAG1 (adenovirus-packaged JAG1 overexpression vector and Ad-NC) to test the role of JAG1 in propofol's analgesic mechanism of action. Finally, the levels of JAG1 and Notch pathway-related proteins were detected RESULTS: Propofol was found to alleviate NP, including thermal hyperalgesia and mechanical pain threshold. Propofol could also ameliorate neuroinflammation by up-regulating the expression of IL-10 and inhibiting the release of TNF-α and IL-1β. Mechanically, propofol enhanced the amount of miR-140-3p in CCI rats via the regulation of JAG1. Down-regulation of miR-140-3p, or up-regulation of JAG1, could reduce the protective effect of propofol against NP. Propofol inhibited the activation of Notch signaling via miR-140-3p/JAG1 to realize its analgesic effect CONCLUSION: Our findings indicated that propofol inhibits inflammatory responses and the Notch signaling pathway via miR-140-3p/JAG1 to alleviate NP. These data provide evidence to support a potential clinical therapy for NP.

Pharmacologic neuroprotection in ischemic brain injury after cardiac arrest

Cardiac arrest has many implications for morbidity and mortality. Few interventions have been shown to improve return of spontaneous circulation (ROSC) and long-term outcomes after cardiac arrest. Ischemic-reperfusion injury upon achieving ROSC creates an imbalance between oxygen supply and demand. Multiple events occur in the postcardiac arrest period, including excitotoxicity, mitochondrial dysfunction, and oxidative stress and inflammation, all of which contribute to ongoing brain injury and cellular death. Given that complex pathophysiology underlies global brain hypoxic ischemia, neuroprotective strategies targeting multiple stages of the neuropathologic cascade should be considered as a means of mitigating secondary neuronal injury and improving neurologic outcomes and survival in cardiac arrest victims. In this review article, we discuss a number of different pharmacologic agents that may have a potential role in targeting these injurious pathways following cardiac arrest. Pharmacologic therapies most relevant for discussion currently include memantine, perampanel, magnesium, propofol, thiamine, methylene blue, vitamin C, vitamin E, coenzyme Q₁₀ , minocycline, steroids, and aspirin.

Propofol suppresses osteosarcoma cell function by regulating FOXO1/TUSC7

OBJECTIVES

Accumulated evidence demonstrates that propofol has antitumour roles in various cancers. However, the role of propofol in osteosarcoma is still unclear. Therefore, we aim to determine the role of propofol on osteosarcoma and further explore its potential mechanism.

METHODS

Cell proliferation, migration and invasion of osteosarcoma were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing and transwell assay, respectively. The interaction between FoxO1 and TUSC7 was determined using luciferase reporter assay and chromatin immunoprecipitation.

RESULTS

Propofol treatment significantly decreased cell proliferation, migration and invasion in U2OS cells. Propofol promoted TUSC7 expression by enhancing transcriptional factor FOXO1 that leads to inactivation of AKT/GSK3β signalling resulting in the suppression of cell proliferation, migration and invasion.

CONCLUSIONS

Propofol suppresses cell proliferation, migration and invasion of osteosarcoma cells through FOXO1/TUSC7 axis by regulating AKT/GSK3β signalling.

Safety and Efficacy of the Combination of Propofol and Ketamine for Procedural Sedation/Anesthesia in the Pediatric Population: A Systematic Review and Meta-analysis

BACKGROUND

Drugs such as propofol and ketamine are used alone or in combination to provide sedation for medical procedures in children. The purpose of this systematic review was to compare the safety and effectiveness of propofol and ketamine to other drug regimens.

METHODS

We searched Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews (CDSR), Web of Science, and the grey literature (meta-Register of Controlled Trials, ClinicalTrials.gov, and Google Scholar) for randomized controlled studies comparing intravenous propofol and ketamine to any other single or combination drug regimen administered to children undergoing diagnostic or therapeutic procedures. Meta-analyses were performed for primary (hemodynamic and respiratory adverse events) and secondary outcomes using RevMan 5.3. We assessed the risk of bias and the certainty (quality) evidence for all outcomes using Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology.

RESULTS

Twenty-nine studies were included for analysis. Based on low-to-moderate quality evidence, we concluded that the use of propofol and ketamine may result in a slight-to-small reduction in the risk of hypotension, bradycardia, and apnea, and a slight increase in the risk of tachycardia, hypertension, and other respiratory adverse events, such as cough or laryngospasm. The ratio of propofol to ketamine and comparator drug regimen subgroups effects were important for desaturation and some secondary outcomes.

CONCLUSIONS

The use of propofol and ketamine had a minimal effect on the incidence of adverse events and other secondary outcomes. Large-scale studies are required to more accurately estimate adverse event rates and the effects of propofol and ketamine on patient-important outcomes.

The Use of Middle Latency Auditory Evoked Potentials (MLAEP) as Methodology for Evaluating Sedation Level in Propofol-Drug Induced Sleep Endoscopy (DISE) Procedure

To analyze the middle latency auditory evoked potential index (MLAEPi), compared to the standard bispectral index (BIS), as a method for evaluating the sedation level in drug-induced sleep endoscopy (DISE). In this controlled clinical study on a sample of 99 obstructive sleep apnea (OSA) or snoring patients, we compared the MLAEPi with the BIS after propofol infusion during the standard DISE technique in order to define the MLAEPi values within the observational window of the procedure. The DISE procedure was divided into eight steps, and we collected both MLAEPi and BIS data values from the same patient in every step. The MLAEPi showed a faster response than the BIS after propofol infusion during DISE. Therefore, the clinical use of the MLAEPi in evaluating the sedation level seems to be a good alternative to the current technological standards.

Effects of Premedication With Midazolam on Recovery and Discharge Times After Tonsillectomy and Adenoidectomy

Background

Midazolam is commonly used preoperatively for anxiety. Adverse effects data in pediatric patients with obstructive sleep apnea (OSA) undergoing tonsillectomy and adenoidectomy (T&A) is limited.

Aims

We hypothesized that preoperative midazolam increases the time to emergence from anesthesia and postoperative discharge. Secondary objectives assessed if patients receiving midazolam experienced increased side effects or complications from treatment.

Methods

This study was a retrospective chart review of patients undergoing T&A from July 2014 to December 2015. Midazolam receiving patients (midazolam group: MG) were compared to patients who did not (non-midazolam group: NMG). Multivariable analyses were performed and adjusted for predefined potential cofounder variables.

Results

Emergence and discharge times were 5.2 minutes (95% CI [-7.1, 17.4]; p=0.41) and 10.1 minutes (95% CI [-6.7, 26.8]; p=0.24) longer in MG. These results were not statistically significant. Comparing by OSA status, there was no statistical difference in emergence and discharge times between mild, moderate and severe OSA groups or between MG and NMG within each OSA group. Emergence and discharge times in moderate OSA was 6.1 minutes (95% CI [-17.6, 29.8]; p=0.61) and 18.8 minutes (95% CI [-16.4, 53.9]; p=0.29) longer than mild OSA, and in the severe OSA group, 2.6 minutes (95% CI [-19.9, 25.1]; p=0.82) shorter and 2.8 minutes (95% CI [-30.3, 35.9]; p=0.87) longer. The incidence of postoperative complications was comparable between MG and NMG groups.

Conclusions

Premedication with midazolam was not associated with prolonged emergence or discharge time or higher incidence of complications after anesthesia for T&A in patients with OSA.

Mechanistic basis of propofol-induced disruption of kinesin processivity

Propofol is a widely used general anesthetic to induce and maintain anesthesia, and its effects are thought to occur through impact on the ligand-gated channels including the GABA_A receptor. Propofol also interacts with a large number of proteins including molecular motors and inhibits kinesin processivity, resulting in significant decrease in the run length for conventional kinesin-1 and kinesin-2. However, the molecular mechanism by which propofol achieves this outcome is not known. The structural transition in the kinesin neck-linker region is crucial for its processivity. In this study, we analyzed the effect of propofol and its fluorine derivative (fropofol) on the transition in the neck-linker region of kinesin. Propofol binds at two crucial surfaces in the leading head: one at the microtubule-binding interface and the other in the neck-linker region. We observed in both the cases the order-disorder transition of the neck-linker was disrupted and kinesin lost its signal for forward movement. In contrast, there was not an effect on the neck-linker transition with propofol binding at the trailing head. Free-energy calculations show that propofol at the microtubule-binding surface significantly reduces the microtubule-binding affinity of the kinesin head. While propofol makes pi-pi stacking and H-bond interactions with the propofol binding cavity, fropofol is unable to make a suitable interaction at this binding surface. Therefore, the binding affinity of fropofol is much lower compared to propofol. Hence, this study provides a mechanism by which propofol disrupts kinesin processivity and identifies transitions in the ATPase stepping cycle likely affected.

Repeated exposure to propofol in the neonatal period impairs hippocampal synaptic plasticity and the recognition function of rats in adulthood

Anesthesia of neonates with propofol induces persistent behavioral abnormalities in adulthood. Although propofol-triggered apoptosis of neurons in the developing brain may contribute to the development of cognitive deficits, the mechanism of neurotoxicity induced by neonatal exposure to propofol remains unclear. In this study, the effects of neonatal propofol anesthesia on synaptic plasticity and neurocognitive function were investigated. Postnatal day 7 (PND-7) Sprague-Dawley rats were intraperitoneally injected with fat emulsion or 20, 40 or 60 mg/kg propofol for three consecutive days. The expression of brain-derived neurotrophic factor (BDNF), tropomyosin-related kinase B (TrkB) and postsynaptic density protein 95 (PSD-95) in the rat hippocampus at PND-10 and PND-12 was measured by Western blotting. The number of dendritic branches, total dendritic length and dendritic spine density were observed by Golgi-Cox staining 24 h and 72 h after the last propofol administration. Long-term potentiation (LTP) was measured electrophysiologically in hippocampus of PND-60 rats to evaluate the synaptic function. The learning and memory abilities of rats were evaluated by Morris water maze (MWM) experiments, Novel object recognition test (NORT) and Object location test (OLT) at PND-60. Our results showed that neonatal exposure to propofol significantly inhibited the expression of BDNF, TrkB and PSD-95 in the rat hippocampus. The number of dendritic branches, total dendritic length and dendritic spine density of neurons in the rat hippocampus were markedly reduced after neonatal propofol anesthesia. LTP was significantly diminished in hippocampus of PND-60 rats after repeated exposure to propofol in the neonatal period. Morris water maze experiments showed that repeated neonatal exposure to propofol significantly prolonged the escape latency and decreased the time spent in the target quadrant and the number of platform crossings. NORT and OLT showed that repeated neonatal exposure to propofol markedly reduced the Investigation Time for novel object or location. All of the results above indicate that repeated exposure to propofol in the neonatal period can impair hippocampal synaptic plasticity and the recognition function of rats in adulthood.

Antiepileptic Drug Therapy for Status Epilepticus

Status epilepticus (SE) is one of the most serious neurologic emergencies. SE is a condition that encompasses a broad range of semiologic subtypes and heterogeneous etiologies. The treatment of SE primarily involves the management of the underlying etiology and the use of antiepileptic drug therapy to rapidly terminate seizure activities. The Drug Committee of the Korean Epilepsy Society performed a review of existing guidelines and literature with the aim of providing practical recommendations for antiepileptic drug therapy. This article is one of a series of review articles by the Drug Committee and it summarizes staged antiepileptic drug therapy for SE. While evidence of good quality supports the use of benzodiazepines as the first-line treatment of SE, such evidence informing the administration of second- or third-line treatments is lacking; hence, the recommendations presented herein concerning the treatment of established and refractory SE are based on case series and expert opinions. The choice of antiepileptic drugs in each stage should consider the characteristics and circumstances of each patient, as well as their estimated benefit and risk to them. In tandem with the antiepileptic drug therapy, careful searching for and treatment of the underlying etiology are required.

Syntheses of Analogues of Propofol: A Review

Propofol (2,6-diisopropylphenol) is an intravenous sedative/hypnotic agent that is used extensively for introduction and maintenance of general anaesthesia, sedation of critically ill patients and procedural sedation (e.g., endoscopy). Propofol has a rapid onset and offset of action and shows only minimal accumulation upon prolonged use. Propofol is only sparingly soluble in water and is currently marketed in 10% soybean oil-based lipid emulsion. Propofol’s anaesthetic properties were discovered over forty years ago, and it has been in clinical use for over thirty years. The main use of propofol remains as an anaesthetic but, over the years, analogues have been developed with varying properties from anticancer, anticonvulsant and antioxidant. In addition, large synthetic efforts have been made towards improving propofol’s water-solubility, its activity, and elucidating its structure–activity­ relationship and exact mechanism of action have been made. This review provides an overview of the research pertaining to propofol-like molecules and covers the efforts of synthetic chemists towards propofol analogues over the last 40 years.

1 Introduction

2 History

3 Early Work

4 Improving Water Solubility

5 The Importance of the Phenol

6 Exploring the Structure–Activity Relationship and Attempts to Improve Activity

7 Anticancer Activity

8 Anticonvulsant Properties

9 Antioxidant Activity

10 Photoactive Labelling to Elucidate Mechanism of Action

11 Photoregulation

12 Conclusion