The inhibitory effects of Orengedokuto on inducible PGE2 production in BV-2 microglial cells.

BACKGROUND AND AIM: Reactive microglia has been associated with neuroinflammation caused by the production of proinflammatory molecules such as cytokines, nitric oxide, and prostaglandins. The overexpression of these molecules may provoke neuronal damage that can cause neurodegenerative diseases. A traditional herbal medicine, Orengedokuto (OGT), has been widely used for treating inflammation-related diseases. However, how it influences neuroinflammation remains poorly understood. EXPERIMENTAL PROCEDURE: This study investigated the effects of OGT on inflammatory molecule induction in BV-2 microglial cells using real-time RT-PCR and ELISA. An in vivo confirmation of these effects was then performed in mice. RESULTS AND CONCLUSION: OGT showed dose-dependent inhibition of prostaglandin E2 (PGE2) production in BV-2 cells stimulated with lipopolysaccharide (LPS). To elucidate the mechanism of PGE2 inhibition, we examined cyclooxygenases (COXs) and found that OGT did not suppress COX-1 expression or inhibit LPS-induced COX-2 upregulation at either the transcriptional or translational levels. In addition, OGT did not inhibit COX enzyme activities within the concentration that inhibited PGE2 production, suggesting that the effect of OGT is COX-independent. The inhibitory effects of OGT on PGE2 production in BV-2 cells were experimentally replicated in primary cultured astrocytes and mice brains. OGT can be useful in the treatment of neuroinflammatory diseases by modulating PGE2 expression.

Maternal exposure to volatile anesthetics induces IL-6 in fetal brains and affects neuronal development.

Most clinically used general anesthetics have demonstrated neurotoxicity in animal studies, but the related mechanisms remain unknown. Previous studies suggest that anesthetics affect neuronal development through neuroinflammation, and significant effects of neuroinflammation on neurogenesis and neuronal disease have been shown. In the present study, we treated pregnant mice with 2% sevoflurane for 3 h at gestational day 15.5 and analyzed the expression of proinflammatory cytokines, including IL-6 and IL-17, in fetal mice brains. Sevoflurane induced IL-6 mRNA significantly, but did not upregulate IL-17. Other volatile anesthetics, including isoflurane, enflurane, and halothane, induced IL-6 mRNA in fetal brains as well as sevoflurane, but propofol did not. Sevoflurane and isoflurane showed the same effects in cultured microglia and astrocytes, but not in neurons. Because IL-6 induction in fetal brains may affect neuronal precursor cells (NPCs), numbers of NPCs in the subventricular zone were studied, revealing that maternal sevoflurane treatment significantly increases NPCs in offspring at 8 weeks after birth (p8wk). But this effect was absent in IL-6 knockout mice. Finally, behavioral experiments also revealed that maternal sevoflurane exposure causes learning impairments in p8wk offspring. These findings collectively demonstrate that maternal exposure to volatile anesthetics upregulates IL-6 in fetal mice brains, and the effects could result in long-lasting influences on neuronal development.

Effect of propofol on androgen receptor activity in prostate cancer cells.

Androgen receptor is a nuclear receptor and transcription factor activated by androgenic hormones. Androgen receptor activity plays a pivotal role in the development and progression of prostate cancer. Although accumulating evidence suggests that general anesthetics, including opioids, affect cancer cell growth and impact patient prognosis, the effect of those drugs on androgen receptor in prostate cancer is not clear. The purpose of this study was to investigate the effect of the general anesthetic propofol on androgen receptor activity in prostate cancer cells. An androgen-dependent human prostate cancer cell line (LNCaP) was stimulated with dihydrotestosterone (DHT) and exposed to propofol. The induction of androgen receptor target genes was investigated using real-time reverse transcription polymerase chain reaction, and androgen receptor protein levels and localization patterns were analyzed using immunoblotting and immunofluorescence assays. The effect of propofol on the proliferation of LNCaP cells was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Propofol significantly inhibited DHT-induced expression of androgen receptor target genes in a dose- and time-dependent manner, and immunoblotting and immunofluorescence assays indicated that propofol suppressed nuclear levels of androgen receptor proteins. Exposure to propofol for 24h suppressed the proliferation of LNCaP cells, whereas 4h of exposure did not exert significant effects. Together, our results indicate that propofol suppresses nuclear androgen receptor protein levels, and inhibits androgen receptor transcriptional activity and proliferation in LNCaP cells.

Midazolam inhibits the hypoxia-induced up-regulation of erythropoietin in the central nervous system.

Erythropoietin (EPO), a regulator of red blood cell production, is endogenously expressed in the central nervous system. It is mainly produced by astrocytes under hypoxic conditions and has proven to have neuroprotective and neurotrophic effects. In the present study, we investigated the effect of midazolam on EPO expression in primary cultured astrocytes and the mouse brain. Midazolam was administered to 6-week-old BALB/c male mice under hypoxic conditions and pregnant C57BL/6N mice under normoxic conditions. Primary cultured astrocytes were also treated with midazolam under hypoxic conditions. The expression of EPO mRNA in mice brains and cultured astrocytes was studied. In addition, the expression of hypoxia-inducible factor (HIF), known as the main regulator of EPO, was evaluated. Midazolam significantly reduced the hypoxia-induced up-regulation of EPO in BALB/c mice brains and primary cultured astrocytes and suppressed EPO expression in the fetal brain. Midazolam did not affect the total amount of HIF proteins but significantly inhibited the nuclear expression of HIF-1α and HIF-2α proteins. These results demonstrated the suppressive effects of midazolam on the hypoxia-induced up-regulation of EPO both in vivo and in vitro.

The volatile anesthetic isoflurane differentially suppresses the induction of erythropoietin synthesis elicited by acute anemia and systemic hypoxemia in mice in an hypoxia-inducible factor-2-dependent manner.

Erythropoietin (EPO) is a glycoprotein hormone essential for the regulation of erythroid homeostasis. Although EPO production is prominent in the kidney and liver, its production in the central nervous system has also been detected. Tissue hypoxia due to systemic or local hypoxemia and acute anemia due to blood loss occurs frequently during various clinical settings, leading to a high possibility of elevated plasma EPO levels. However, it is largely unknown whether volatile anesthetic agents affect EPO production elicited by acute hypoxia in vivo. Male C57BL/6N CrSlc mice were exposed to a hypoxic insult as a result of bleeding-related anemia or hypoxemia while they were under anesthetized using various concentrations of isoflurane. EPO protein concentrations were assessed by enzyme-linked immunosorbent assay and mRNA levels were measured by quantitative real-time reverse transcriptase-polymerase chain reaction. Plasma EPO concentration was induced as early as 3h following acute anemic and hypoxemic hypoxia and suppressed by clinically relevant doses of isoflurane in a dose-dependent manner. Anemic hypoxia induced EPO mRNA and protein synthesis in the kidney. In the kidney, isoflurane inhibited EPO induction caused by anemia but not that caused by hypoxemia. On the other hand, in the brain hypoxemia-induced EPO production was suppressed by isoflurane. Finally, qRT-PCR studies demonstrate that isoflurane differentially inhibit HIF-1α and HIF-2α mRNA expression in brain and kidney, indicating the involvement of HIF-2 in the hypoxia-induced EPO expression and inhibition of the induction by isoflurane.

General anesthetics inhibit LPS-induced IL-1ß expression in glial cells.

BACKGROUND: Glial cells, including microglia and astrocytes, are considered the primary source of proinflammatory cytokines in the brain. Immune insults stimulate glial cells to secrete proinflammatory cytokines that modulate the acute systemic response, which includes fever, behavioral changes, and hypothalamic-pituitary-adrenal (HPA) axis activation. We investigated the effect of general anesthetics on proinflammatory cytokine expression in the primary cultured glial cells, the microglial cell line BV-2, the astrocytic cell line A-1 and mouse brain. METHODOLOGY/PRINCIPAL FINDINGS: Primary cultured glial cells were exposed to lipopolysaccharide (LPS) in combination with general anesthetics including isoflurane, pentobarbital, midazolam, ketamine, and propofol. Following this treatment, we examined glial cell expression of the proinflammatory cytokines interleukin (IL)-1ß, IL-6, and tumor necrosis factor-alpha (TNF-α). LPS-induced expression of IL-1ß mRNA and protein were significantly reduced by all the anesthetics tested, whereas IL-6 and TNF-α mRNA expression was unaffected. The anesthetics suppressed LPS-induced extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation, but did not affect nuclear factor-kappaB and activator protein-1 activation. The same effect was observed with BV-2, but not with A-1 cells. In the mouse experiments, LPS was injected intraperitoneally, and isoflurane suppressed IL-1ß in the brain and adrenocorticotropic hormone in plasma, but not IL-1ß in plasma. CONCLUSIONS/SIGNIFICANCE: Taken together, our results indicate that general anesthetics inhibit LPS-induced IL-1ß upregulation in glial cells, particularly microglia, and affects HPA axis participation in the stress response.

Differential roles of prostaglandin E-type receptors in activation of hypoxia-inducible factor 1 by prostaglandin E1 in vascular-derived cells under non-hypoxic conditions.

Prostaglandin E1 (PGE1), known pharmaceutically as alprostadil, has vasodilatory properties and is used widely in various clinical settings. In addition to acute vasodilatory properties, PGE1 may exert beneficial effects by altering protein expression of vascular cells. PGE1 is reported to be a potent stimulator of angiogenesis via upregulation of VEGF expression, which is under the control of the transcription factor hypoxia-inducible factor 1 (HIF-1). However, the molecular mechanisms behind the phenomenon are largely unknown. In the present study, we investigated the mechanism by which PGE1 induces HIF-1 activation and VEGF gene expression in human aortic smooth muscle cells (HASMCs) and human umbilical vein endothelial cells (HUVECs), both vascular-derived cells. HUVECs and HASMCs were treated with PGE1 at clinically relevant concentrations under 20% O2 conditions and HIF-1 protein expression was investigated. Expression of HIF- 1α protein and the HIF-1-downstream genes were low under 20% O2 conditions and increased in response to PGE1 treatment in both HUVECs and HASMCs in a dose- and time-dependent manner under 20% O2 conditions as comparable to exposure to 1% O2 conditions. Studies using EP-receptor-specific agonists and antagonists revealed that EP1 and EP3 are critical to PGE1-induced HIF-1 activation. In vitro vascular permeability assays using HUVECs indicated that PGE1 increased vascular permeability in HUVECs. Thus, we demonstrate that PGE1 induces HIF- 1α protein expression and HIF-1 activation under non-hypoxic conditions and also provide evidence that the activity of multiple signal transduction pathways downstream of EP1 and EP3 receptors is required for HIF-1 activation.

Is recall of dreaming during anesthesia a sign of occurrence of postoperative nausea and vomiting?

We examined the relationships between recall of dreaming during anesthesia and postoperative nausea and vomiting (PONV). We found a relationship between PONV within 24 h and age <50 years, use of postoperative epidural analgesia with morphine, and female gender. We also found a relationship between PONV lasting more than 24 h and dream recall. As serotonin plays an important role for both inducing PONV and dream recall, results of the present study may suggest a possible relationship between dream recall and PONV.

Risk factors for postoperative mortality and morbidities in emergency surgeries.

BACKGROUND: Emergency surgery itself induces high risk for postoperative mortality and morbidities; however, it remains unknown which concomitant pathological conditions of emergency surgeries are causative factors of deteriorating outcomes. This study examined the causal factors of postoperative mortality and morbidity in cases of emergency surgery. METHODS: Patients undergoing emergency surgery from January to December 2007 were enrolled in this retrospective cohort study. Causal relationships were analyzed by stepwise multivariate logistic regression analysis between possible independent factors (sex, age, kind of surgical department, timing of surgery, duration of surgery, blood transfusion, deteriorated consciousness level, shock state, abnormal coagulate state, and history of hypertension, diabetes, ischemic heart disease, chronic obstructive pulmonary disease, renal failure, and anemia) and postoperative mortality or morbidities (failure of removal of tracheal tube after operation, tracheotomy, cerebral infarction, massive hemorrhage, severe hypotension, severe hypoxemia, and severe arrhythmia during or after surgery). RESULTS: Shock, deteriorated consciousness level, chronic obstructive lung disease, and ischemic heart disease were significant risk factors for mortality (OR 14.2, 7.9, 6.4, and 3.8, respectively), and deteriorated consciousness level, blood transfusion, shock, chronic obstructive lung disease, diabetes, cardiovascular surgery, and operation longer than 2 h were significant risk factors for morbidity (OR 19.1, 3.3, 3.0, 2.5, 2.4, 2.4, and 1.8, respectively). CONCLUSION: State of shock, deteriorated consciousness level, chronic obstructive lung disease, ischemic heart disease, hemorrhage requiring blood transfusion, age over 80 years, cardiovascular surgery, surgeries at night, and surgeries of duration more than 2 h cause patients to be strongly susceptible to postoperative mortality or morbidity in emergency surgeries.