Anesthetic propofol overdose causes endothelial cytotoxicity in vitro and endothelial barrier dysfunction in vivo

Overdose with the anesthetic propofol causes hematological cytotoxicity and immune cell alteration in an experimental ex vivo whole blood culture model

Propofol, an anesthetic characterized by its benefits of rapid induction, maintenance, and recovery times, may cause cytotoxic effects, resulting in propofol infusion syndrome (PRIS). In addition to causing dyslipidemia in PRIS, our previous works showed that propofol overdose induced phagocyte apoptosis. This study, using an experimental ex vivo model of propofol treatment, investigated the possible cytopathology in the blood. A complete blood count examination showed the deregulating effects of propofol overdose 24 h postinoculation, characterized by mononuclear cell increase (lymphocyte and monocyte subsets) and granulocyte decrease. Advanced marker-based flow cytometric analysis confirmed these findings, although there was no change in CD14+ monocytes. Blood smear staining showed the deregulating effects of propofol overdose 24 h postinoculation, characterized by cytosolic vacuolization and cytotoxicity, particularly in neutrophils. Immune cell profiling of caspase-3 activation demonstrated the induction of cell apoptosis following propofol overdose treatment, particularly in granulocytes. Using multiparameter flow cytometry, this study further analyzed the changes in the profile of immune cells, showing a notable increase in CD4 + HLA-DR-CD62L- helper T cells. These studies explored an ex vivo model of cytopathogenic propofol overdose and its special immune-deregulating effects on peripheral blood cells.

Propofol Affords No Protection against Delayed Cerebral Ischemia in a Mouse Model of Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is an important contributor to poor outcomes in aneurysmal subarachnoid hemorrhage (SAH) patients. We previously showed that volatile anesthetics such as isoflurane, sevoflurane and desflurane provided robust protection against SAH-induced DCI, but the impact of a more commonly used intravenous anesthetic agent, propofol, is not known. The goal of our current study is to examine the neurovascular protective effects of propofol on SAH-induced DCI. Twelve-week-old male wild-type mice were utilized for the study. Mice underwent endovascular perforation SAH or sham surgery followed one hour later by propofol infusion through the internal jugular vein (2 mg/kg/min continuous intravenous infusion). Large artery vasospasm was assessed three days after SAH. Neurological outcome assessment was performed at baseline and then daily until animal sacrifice. Statistical analysis was performed via one-way ANOVA and two-way repeated measures ANOVA followed by the Newman-Keuls multiple comparison test with significance set at p < 0.05. Intravenous propofol did not provide any protection against large artery vasospasm or sensory-motor neurological deficits induced by SAH. Our data show that propofol did not afford significant protection against SAH-induced DCI. These results are consistent with recent clinical studies that suggest that the neurovascular protection afforded by anesthetic conditioning is critically dependent on the class of anesthetic agent.

Propofol produces neurotoxicity by inducing mitochondrial apoptosis

Propofol is a fast and short-acting intravenous anesthetic widely used in clinical anesthesia and intensive care unit sedation. However, its use can cause abnormal effects on the central nervous system. Thus, the purpose of this study was to investigate the mechanism of propofol on primary hippocampal neuron injury. In addition, we aimed to determine whether a correlation exists between propofol and mitochondrial apoptosis-induced neurotoxicity. Hippocampal neurons cultured for 4 days were exposed to different drugs. The treatment groups were divided according to drug exposure into propofol, a rotenone inhibitor, and a coenzyme Q10 agonist groups. The final concentrations of propofol were 1, 10 and 100 µM. The content of ATP and reactive oxygen species (ROS) in the neurons of each group were detected using commercial kits in the culture supernatant after 3 h of drug exposure. Western blotting was used to analyze the expression of apoptosis-related proteins. The JC-1 kit was used to detect the mitochondrial membrane potential. The results revealed that, compared with the non-propofol treatment groups, the expression of apoptosis-related proteins, ATP content, and mitochondrial membrane potential were significantly decreased while the ROS content was markedly increased in the propofol treatment group. In conclusion, propofol treatment promoted damage to hippocampal neuronal mitochondria in a dose-dependent manner. This damage may lead to neuronal apoptosis and neurotoxicity by inducing the inhibition of mitochondrial respiratory chain complex I.

The Protective Effects of Benzbromarone Against Propofol-Induced Inflammation and Injury in Human Brain Microvascular Endothelial Cells (HBMVECs)

It has been widely reported that severe neurotoxicity can be induced by the application of propofol, which is closely related to the disruption of the blood-brain barrier (BBB) induced by inflammation and injury in the human brain microvascular endothelial cells (HBMVECs). Benzbromarone is a classic anti-gout agent that has been recently reported to exert anti-inflammatory and anti-oxidative stress effects. In the present study, we aim to investigate the protective property of Benzbromarone against propofol-induced injury on HBMVECs and the underlying mechanism. CCK8 assay was used to detect the cell viability of treated HBMVECs. Oxidative stress in HBMVECs was evaluated by measuring the levels of MDA and mitochondrial ROS. ELISA and qRT-PCR assay were used to determine the production of IL-1β, IL-8, MCP-1, ICAM-1, and VCAM-1 by treated HBMVECs. Calcein-AM staining was utilized to evaluate the attachment of U937 monocytes to HBMVECs. The expression level of Egr-1 was determined by qRT-PCR and Western blot assay. Firstly, the decreased cell viability of HBMVECs induced by propofol was significantly elevated by treatment with Benzbromarone. The increased levels of MDA and mitochondrial ROS induced by propofol were dramatically suppressed by Benzbromarone. Secondly, the excessive production of inflammatory factors (IL-1β, IL-8, and MCP-1) and adhesion molecules (ICAM-1 and VCAM-1) triggered by propofol was pronouncedly inhibited by Benzbromarone. Benzbromarone ameliorated propofol-induced attachment of U937 monocytes to HBMVECs. Lastly, Benzbromarone downregulated propofol-induced expression of the transcriptional factor Egr-1 in HBMVECs. Benzbromarone protected against propofol-induced inflammation and injury through suppressing Egr-1 in human brain vascular endothelial cells.

Oxidative damage of lysosomes in regulated cell death systems: Pathophysiology and pharmacologic interventions

Lysosomes are small specialized organelles containing a variety of different hydrolase enzymes that are responsible for degradation of all macromolecules, entering the cells through the endosomal system or originated from the internal sources. This allows for transport and recycling of nutrients and internalization of surface proteins for antigen presentation as well as maintaining cellular homeostasis. Lysosomes are also important storage compartments for metal ions and nutrients. The integrity of lysosomal membrane is central to maintaining their normal function, but like other cellular membranes, lysosomal membrane is subject to damage mediated by reactive oxygen species. This results in spillage of lysosomal enzymes into the cytoplasm, leading to proteolytic damage to cellular systems and organelles. Several forms of lysosomal dependent cell death have been identified in diseases. Examination of these events are important for finding treatment strategies relevant to cancer or neurodegenerative diseases as well as autoimmune deficiencies. In this review, we have examined the current literature on involvement of lysosomes in induction of programed cell death and have provided an extensive list of therapeutic approaches that can modulate cell death. Exploitation of these mechanisms can lead to novel therapies for cancer and neurodegenerative diseases.

Propofol induces apoptosis by activating caspases and the MAPK pathways, and inhibiting the Akt pathway in TM3 mouse Leydig stem/progenitor cells

Propofol is an anesthetic agent moderating GABA receptors in the nervous system. A number of studies have demonstrated that propofol exerts a negative effect on neural stem cell development in the neonatal mouse hippocampus. However, to the best of our knowledge, there is no study available to date illustrating whether neonatal exposure to propofol affects Leydig stem/progenitor cell development for normal male reproductive development and functions, and the regulatory mechanism remains elusive. In the present study, TM3 cells, a mouse Leydig stem/progenitor cell line, was treated with propofol. The data illustrated that propofol significantly reduced TM3 cell viability. TM3 subG1 phase cell numbers were significantly increased by propofol assayed by flow cytometric analysis. Annexin V/PI double staining assay of the TM3 Leydig cells also demonstrated that propofol increased TM3 cell apoptosis. In addition, cleaved caspase‑8, ‑9 and ‑3 and/or poly(ADP‑ribose) polymerase (PARP) were significantly activated by propofol in the TM3 cells. Furthermore, the expression levels of phospho‑JNK, phospho‑ERK1/2 and phospho‑p38 were activated by propofol in the TM3 cells, indicating that propofol induced apoptosis through the mitogen‑activated protein kinase (MAPK) pathway. Additionally, propofol diminished the phosphorylation of Akt to increase the apoptosis of TM3 cells. On the whole, the findings of the present study demonstrate that propofol induces TM3 cell apoptosis by activating caspases and MAPK pathways, as well as by inhibiting the Akt pathway in TM3 cells. These findings illustrate that propofol affects the viability of Leydig stem/progenitor cells possibly related to the development of the male reproductive system.

Effects of Anesthetics on Barrier Tissue Function

Anesthetics have long been proven to have additional effects other than anesthesia on different organs and tissues of the human body. Barrier tissues play critical roles in human health and diseases, yet the impacts of anesthetics on barrier tissues are still not clear. This review article is aimed at summarizing different effects of anesthetics on the skin, the respiratory, and intestinal membranes from two aspects: inflammation/immunity and ischemia-reperfusion. Among volatile, intravenous, and local anesthetics, volatile anesthetics are less influential on barrier ischemia-perfusion function. Although direct comparisons between volatile and the other two types of anesthetics are still lacking, volatile anesthetics appear to have stronger anti-inflammatory effects on different barrier tissues through various mechanisms. These results suggested that when treating patients with barrier tissue complications, volatile anesthetics can provide better therapeutic outcomes.

Effects of propofol on wound closure and barrier function of cultured endothelial cells: An in vitro experimental study

BACKGROUND

Propofol is widely used in routine clinical practice for the induction and maintenance of anaesthesia. Although propofol is regarded as a well tolerated anaesthetic, its effect on intact or damaged endothelial cells has not yet been elucidated.

OBJECTIVE

The aim of this study was to investigate the effects of different concentrations of propofol on cell damage, metabolic activity, barrier function and wound healing capacity of human endothelial cells.

DESIGN

An in vitro investigation.

SETTING

Research Laboratory of the Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Kiel, Germany.

MATERIALS

In vitro cultures of primary human umbilical vein endothelial cells (HUVECs).

INTERVENTIONS

Intact HUVEC or wounded HUVEC monolayers were incubated with or without different concentrations of propofol (10, 30 and 100 μmol l).

MAIN OUTCOME MEASURES

Cell damage, metabolic activity, monolayer permeability, wound healing capacity, protein phosphorylation.

RESULTS

Propofol did not alter the morphology, induce cell damage or influence metabolic activity of intact HUVEC cells. Permeability of a HUVEC monolayer was increased by propofol 100 μmol l (P < 0.05). Wound closure was inhibited by the addition of propofol 30 and 100 μmol l (P < 0.05 and P < 0.01). This effect was associated with increased phosphorylation of extracellular signal regulated kinases (Erk) 1/2 (30 and 100 μmol l; both P < 0.05) and decreased phosphorylation of Rho kinase (Rock) (100 μmol l; P < 0.05).

CONCLUSION

Propofol does not damage intact endothelial cells, but increases permeability of an endothelial cell monolayer at high concentrations and inhibits wound closure in vitro. Further experimental and clinical in vivo research should be performed to clarify the influence of propofol on endothelial wound healing.

The interplay of BDNF-TrkB with NMDA receptor in propofol-induced cognition dysfunction : Mechanism for the effects of propofol on cognitive function

Background

The aim of the present study was to verify whether propofol impaired learning and memory through the interplay of N-methyl-D-aspartate (NMDA) receptor with brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB) signaling pathway.

Methods

120 Sprague-Dawley (SD) rats were randomly assigned into eight groups. Experimental drugs including saline, intralipid, propofol, N-methyl-D-aspartate (NMDA), 7,8-dihydroxyflavone (7,8-DHF), K252a and MK-801. Spatial learning and memory of rats were tested by the Morris water maze (MWM) test. The mRNA and protein expression were determined by immunohistochemistry, RT-PCR and western blot. Finally, hippocampus cells proliferation and apoptosis were examined by PCNA immunohistochemistry and TUNEL respectively.

Results

The memory and learning was diminished in the propofol exposure group, however, the impaired memory and learning of rats were improved with the addition of NMDA and 7,8-DHF, while the improvement of memory and learning of rats were reversed with the addition of K252a and MK-801. In addition, the mRNA and protein expression levels and hippocampus cells proliferation were the same trend with the results of the MWM test, while apoptosis in hippocampus was reversed.

Conclusion

The propofol can impair memory and learning of rats and induce cognition dysfunction through the interplay of NMDA receptor and BDNF-TrkB-CREB signaling pathway.

Propofol Sedation Exacerbates Kidney Pathology and Dissemination of Bacteria during Staphylococcus aureus Bloodstream Infections

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for large numbers of postsurgical nosocomial infections across the United States and worldwide. Propofol anesthesia is widely used in surgery and in intensive care units, and recent evidence indicates that even brief exposure to propofol can substantially increase host susceptibility to microbial infection. Here, we delineate the impact of propofol sedation on MRSA bloodstream infections in mice in the presence and absence of prophylactic antibiotic treatment. Consistent with previous reports, brief periods of anesthesia with propofol were sufficient to significantly increase bacterial burdens and kidney pathology in mice infected with MRSA. Propofol exposure increased neutrophilic infiltrates into the kidney and enhanced bacterial dissemination throughout kidney tissue. Propofol sedation reduced populations of effector phagocytes and mature dendritic cells within the kidney and led to the apparent expansion of myeloid-derived suppressor cell-like populations. When propofol was coadministered with vancomycin prophylaxis, it dramatically increased kidney abscess formation and bacterial dissemination throughout kidney tissue at early times post-S. aureus infection compared to antibiotic-treated but nonsedated animals. Taken together, our data indicate that short-term sedation with propofol significantly increases the severity of bloodstream MRSA infection, even when administered in conjunction with vancomycin prophylaxis.

Propofol exposure during late stages of pregnancy impairs learning and memory in rat offspring via the BDNF-TrkB signalling pathway

The brain‐derived neurotrophic factor (BDNF)‐tyrosine kinase B (TrkB) (BDNF‐TrkB) signalling pathway plays a crucial role in regulating learning and memory. Synaptophysin provides the structural basis for synaptic plasticity and depends on BDNF processing and subsequent TrkB signalling. Our previous studies demonstrated that maternal exposure to propofol during late stages of pregnancy impaired learning and memory in rat offspring. The purpose of this study is to investigate whether the BDNF‐TrkB signalling pathway is involved in propofol‐induced learning and memory impairments. Propofol was intravenously infused into pregnant rats for 4 hrs on gestational day 18 (E18). Thirty days after birth, learning and memory of offspring was assessed by the Morris water maze (MWM) test. After the MWM test, BDNF and TrkB transcript and protein levels were measured in rat offspring hippocampus tissues using real‐time PCR (RT‐PCR) and immunohistochemistry (IHC), respectively. The levels of phosphorylated‐TrkB (phospho‐TrkB) and synaptophysin were measured by western blot. It was discovered that maternal exposure to propofol on day E18 impaired spatial learning and memory of rat offspring, decreased mRNA and protein levels of BDNF and TrkB, and decreased the levels of both phospho‐TrkB and synaptophysin in the hippocampus. Furthermore, the TrkB agonist 7,8‐dihydroxyflavone (7,8‐DHF) reversed all of the observed changes. Treatment with 7,8‐DHF had no significant effects on the offspring that were not exposed to propofol. The results herein indicate that maternal exposure to propofol during the late stages of pregnancy impairs spatial learning and memory of offspring by disturbing the BDNF‐TrkB signalling pathway. The TrkB agonist 7,8‐DHF might be a potential therapy for learning and memory impairments induced by maternal propofol exposure.

Propofol infusion syndrome: a structured review of experimental studies and 153 published case reports

INTRODUCTION

Propofol infusion syndrome (PRIS) is a rare, but potentially lethal adverse effect of a commonly used drug. We aimed to review and correlate experimental and clinical data about this syndrome.

METHODS

We searched for all case reports published between 1990 and 2014 and for all experimental studies on PRIS pathophysiology. We analysed the relationship between signs of PRIS and the rate and duration of propofol infusion causing PRIS. By multivariate logistic regression we looked at the risk factors for mortality.

RESULTS

Knowledge about PRIS keeps evolving. Compared to earlier case reports in the literature, recently published cases describe older patients developing PRIS at lower doses of propofol, in whom arrhythmia, hypertriglyceridaemia and fever are less frequently seen, with survival more likely. We found that propofol infusion rate and duration, the presence of traumatic brain injury and fever are factors independently associated with mortality in reported cases of PRIS (area under receiver operator curve = 0.85). Similar patterns of exposure to propofol (in terms of time and concentration) are reported in clinical cases and experimental models of PRIS. Cardiac failure and metabolic acidosis occur early in a dose-dependent manner, while arrhythmia, other electrocardiographic changes and rhabdomyolysis appear more frequently after prolonged propofol infusions, irrespective of dose.

CONCLUSION

PRIS can develop with propofol infusion <4 mg/kg per hour and its diagnosis may be challenging as some of its typical features (hypertriglyceridaemia, fever, hepatomegaly, heart failure) are often (>95 %) missing and others (arrhythmia, electrocardiographic changes) occur late.

"Micro to macro (M2M)"--A novel approach for intravenous delivery of propofol

PURPOSE

Propofol emulsions have limited shelf life and safety concerns for injection. Microemulsions of propofol are thermodynamically stable and simpler to manufacture, but cause additional pain on injection. We propose a novel micro to macro (M2M) approach of destabilizing a microemulsion immediately prior to injection.

METHODS

Microemulsions of propofol were prepared at two to three times the drug loadings of commercial formulations. We determined suitable microemulsion compositions which destabilize into macroemulsions after two or three fold dilutions with water. Droplet growth after dilution was measured with dynamic light scattering. Increasing solution turbidity after dilution was also measured optically with millisecond resolution. Experimental data was analyzed in the context of a coalescence model.

RESULTS

Microemulsions rapidly coalesce into larger droplet size macroemulsions after dilution according to the phase diagram shift. The resulting macroemulsions are metastable retaining their droplet size for several hours. Droplet growth occurs on the order of seconds and a metastable size of about 1 micron is reached in minutes. Rates of droplet growth and metastable droplet sizes depend on the surfactant composition. The coalescence model predicts droplet growth with good agreement but only after accounting for the finite probability of coalescence from each collision.

CONCLUSIONS

The M2M concept has been demonstrated for the anesthetic drug propofol which may improve stability and manufacturability in addition to reducing pain on injection. This approach could be adapted to other hydrophobic vesicant drugs as well.

Anesthetic propofol overdose causes vascular hyperpermeability by reducing endothelial glycocalyx and ATP production

Prolonged treatment with a large dose of propofol may cause diffuse cellular cytotoxicity; however, the detailed underlying mechanism remains unclear, particularly in vascular endothelial cells. Previous studies showed that a propofol overdose induces endothelial injury and vascular barrier dysfunction. Regarding the important role of endothelial glycocalyx on the maintenance of vascular barrier integrity, we therefore hypothesized that a propofol overdose-induced endothelial barrier dysfunction is caused by impaired endothelial glycocalyx. In vivo, we intraperitoneally injected ICR mice with overdosed propofol, and the results showed that a propofol overdose significantly induced systemic vascular hyperpermeability and reduced the expression of endothelial glycocalyx, syndecan-1, syndecan-4, perlecan mRNA and heparan sulfate (HS) in the vessels of multiple organs. In vitro, a propofol overdose reduced the expression of syndecan-1, syndecan-4, perlecan, glypican-1 mRNA and HS and induced significant decreases in the nicotinamide adenine dinucleotide (NAD+)/NADH ratio and ATP concentrations in human microvascular endothelial cells (HMEC-1). Oligomycin treatment also induced significant decreases in the NAD+/NADH ratio, in ATP concentrations and in syndecan-4, perlecan and glypican-1 mRNA expression in HMEC-1 cells. These results demonstrate that a propofol overdose induces a partially ATP-dependent reduction of endothelial glycocalyx expression and consequently leads to vascular hyperpermeability due to the loss of endothelial barrier functions.