Nuan-Yen Su

Mackay Memorial Hospital, T’ai-pei, Taipei, Taiwan

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Publications (6)7.74 Total impact

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    ABSTRACT: We previously demonstrated that inhibiting phosphoinositide 3-kinase (PI3K) or activating L-type calcium channels blocked the anti-inflammatory effects of magnesium sulfate (MgSO4). However, the question of which class I PI3K isoform(s) (PI3Kα, PI3Kβ, PI3Kδ or PI3Kγ) is involved in this regard remains un-studied. The question of whether MgSO4 and L-type calcium channels interact to influence PI3K activation also remains un-studied. We therefore designed this study to test two hypotheses: 1) inhibiting PI3Kα, PI3Kβ, PI3Kδ or PI3Kγ would block the anti-inflammatory effects of MgSO4; 2) activating L-type calcium channels would block the effects of MgSO4 on activating PI3K.
    No preview · Article · Apr 2015 · Journal of Surgical Research
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    ABSTRACT: Background: Phosphoinositide 3-kinase (PI3K) delta and gamma (the p110δ and p110γ isoforms of PI3K) actively participate in the process of inflammation. We sought to elucidate the possible roles of PI3Kδ and PI3Kγ in mediating the anti-inflammation effects of naloxone. Materials and methods: Murine macrophages were treated with endotoxin, endotoxin plus naloxone, or endotoxin plus naloxone plus the PI3K inhibitors (the PI3Kδ inhibitor IC87114, the PI3Kγ inhibitor AS252424, or IC87114 plus AS252424) and denoted as the LPS, LPS + N, LPS + N + IC, LPS + N + AS, and LPS + N + IC + AS group, respectively. Differences in inflammatory molecules and levels of nuclear factor-κB (NF-κB) activation and Akt activation (indicator of PI3K activity) among these groups were compared. Results: The concentrations of inflammatory molecules (macrophage inflammatory protein 2, tumor necrosis factor-α, interleukin-1β, and cyclooxygenase-2/prostaglandin E2) and the levels of NF-κB activation (p-NF-κB p65 and p-inhibitor-κB concentrations and NF-κB-DNA binding activity) of the LPS + N group were significantly lower than those of the LPS group (all P < 0.001). These data confirmed the anti-inflammation effects of naloxone. Moreover, the anti-inflammation effects of naloxone could be counteracted by the inhibitors of PI3Kδ and PI3Kγ, as the concentrations of inflammatory molecules and the levels of NF-κB activation of the LPS + N group were significantly lower than those of the LPS + N + IC, LPS + N + AS, and LPS + N + IC + AS groups (all P < 0.05). In contrast, the concentration of phosphorylated Akt of the LPS + N group was significantly higher than those of the LPS, LPS + N + IC, LPS + N + AS, and LPS + N + IC + AS groups (all P < 0.05). Conclusions: PI3Kδ and PI3Kγ play crucial roles in mediating the anti-inflammation effects of naloxone.
    No preview · Article · Jun 2014 · Journal of Surgical Research
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    ABSTRACT: We sought to elucidate whether enhancing phosphoinositide 3-kinase (PI3K)/Akt activity is a crucial mechanism underlying the anti-inflammation effects of magnesium sulfate (MgSO4). Murine macrophages (RAW264.7 cells) were stimulated with endotoxin, endotoxin plus MgSO4, or endotoxin plus MgSO4 plus PI3K inhibitor (LY294002 or wortmannin). Control groups were run simultaneously. After harvesting, we assayed the expression of inflammatory mediators, transcriptional factor nuclear factor κB (NF-κB), and Akt. MgSO4 significantly attenuated endotoxin-induced upregulation of inflammatory mediators and NF-κB, as macrophages treated with endotoxin plus MgSO4 had significantly lower tumor necrosis factor α (P = 0.022), macrophage inflammatory protein 2 (P = 0.040), phosphorylated (p)-NF-κB p65 (P = 0.003) and p-inhibitor-κB (P < 0.001) concentrations as well as lower NF-κB DNA binding (P = 0.001) than macrophages treated with endotoxin alone. Moreover, macrophages treated with endotoxin plus MgSO4 plus LY294002 or wortmannin had significantly higher tumor necrosis factor α (P = 0.013 and P < 0.001), macrophage inflammatory protein 2 (P = 0.023 and P = 0.003), p-NF-κB p65 (P = 0.006 and P < 0.001), and p-inhibitor-κB (P = 0.001 and P < 0.001) concentrations, as well as higher NF-κB DNA binding (P = 0.038 and P = 0.009), than macrophages treated with endotoxin plus MgSO4, suggesting that PI3K inhibitors reversed these effects of MgSO4. In contrast, macrophages treated with endotoxin plus MgSO4 had significantly higher p-Akt concentration than macrophages treated with endotoxin alone (P = 0.004). Moreover, macrophages treated with endotoxin plus MgSO4 also had significantly higher p-Akt concentration than macrophages treated with endotoxin plus MgSO4 plus LY294002 or wortmannin (P = 0.004 and P < 0.001). Enhancing PI3K/Akt activity is a crucial mechanism underlying the anti-inflammation effects of MgSO4.
    No preview · Article · Jul 2013 · Journal of Surgical Research
  • Nuan-Yen Su · Pei-Shan Tsai · Chun-Jen Huang
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    ABSTRACT: Up-regulation of inducible nitric oxide synthase (iNOS) plays a crucial role in initiating systemic inflammatory response during sepsis. Clonidine, a widely used anti-hypertension agent and an effective adjunct to anesthesia/sedation and pain management, has been shown to enhance iNOS expression, but the mechanisms underlying its action remain unstudied. Among the possible mechanisms, enzyme induction and enzyme stability are two most likely ones. Endotoxin-induced iNOS induction is regulated by nuclear factor-kappaB (NF-kappaB). Stability of iNOS mRNA is regulated by RNA stabilizing factor, e.g., Hu antigen R (HuR), and RNA destabilizing factors, e.g., AU-rich element/poly(U) binding factor-1 (AUF-1) and tristetraprolin (TTP). We sought to elucidate which of these enzymes is involved in the clonidine-induced enhancement of iNOS expression. Confluent murine macrophages were randomized to receive 1x phosphated buffer saline, clonidine (100 mum), lipopolysaccharide (LPS, 100 ng/mL), or LPS plus clonidine (100 microm). Expression of iNOS and stability of iNOS mRNA were then measured. Expression of the aforementioned relevant enzymes in each group was also analyzed. Clonidine significantly enhanced LPS-induced iNOS expression. Clonidine also significantly enhanced LPS-induced NF-kappaB activation by enhancing the nuclear translocation of NF-kappaB as well as increasing the NF-kappaB-DNA binding activity. However, clonidine did not affect iNOS mRNA stability. The LPS-induced expression of AUF-1 and TTP but not HuR was significantly enhanced by clonidine. NF-kappaB is involved in the clonidine-induced enhancement of iNOS expression in endotoxin-activated macrophages. Clonidine exerts its action on iNOS expression through increasing enzyme induction instead of enzyme stability.
    No preview · Article · Feb 2008 · Journal of Surgical Research
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    ABSTRACT: Bolus thermodilution cardiac output (BCO) measurement has been considered as the "gold standard" for cardiac output (CO) measurement. However, it requires placement of a pulmonary artery (PA) catheter, and questions have been raised regarding the risk/benefit ratio of this invasive technique. Furthermore, great variations between measurements have been reported. Continuous thermodilution CO (CCO) measurement is reported to be a better alternative, but it still requires the placement of a PA catheter. Esophageal echo-Doppler ultrasonography (ED) provides non-invasive continuous measurement of CO (ED-CO). This study was thus designed to compare the agreement between ED-CO and both thermodilution techniques (BCO and CCO). Twenty-four patients undergoing primary coronary artery bypass graft surgery were randomized to have a PA catheter placed for measurement of either BCO or CCO. All patients also had an ED probe placed. In Group I patients (n = 12), BCO measurement was carried out every 15 minutes throughout the surgery except during cardiopulmonary bypass, with concurrent ED-CO reading recorded at the same time point. In Group II patients (n = 12), CCO and ED-CO measurements were recorded at the same designated points of time as in Group I. The agreement between methods (BCO vs. ED-CO or CCO vs. ED-CO) was assessed using Bland-Altman method. The range of measured CO of each method was 2.1 to 9.4 l/min for BCO, 2.4 to 9.2 l/min for CCO and 2.3 to 8.9 l/min for ED-CO. ED-CO and CCO had excellent agreement with a linear regression coefficient (r2 value) of 0.846, and a bias (mean difference) and SD of bias of 0.05 +/- 0.49 l/min. In contrast, the agreement between BCO and ED-CO was poorer; correlation was low (r2 value 0.406) and both the bias and SD of bias were high (0.11 +/- 1.12 l/min). Furthermore, BCO measurements had poor reproducibility, whereas both ED-CO and CCO measurements had good reproducibility. Esophageal echo-Doppler ultrasonography is a satisfactory alternative for cardiac output measurement because it gives a value in good agreement with CCO measurement. With significant between-measurement variations, the accuracy and precision of BCO are uncertain, and it should not be considered as the "gold standard".
    Full-text · Article · Oct 2002 · Acta anaesthesiologica Sinica
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    ABSTRACT: Hemorrhagic shock upregulates inducible nitric oxide (NO) synthase (iNOS) expression and the resultant NO overproduction. Liver is one of the major organs that is responsible for increased NO production after trauma-hemorrhage and resuscitation. Guanosine triphosphate cyclohydrolase I (GTPCH) is the rate-limiting enzyme for the synthesis of tetrahydrobiopterin (BH4), a necessary co-factor for iNOS activity. Very little is known about the effects of hemorrhagic shock on hepatic GTPCH expression. Fifteen male Sprague-Dawley rats were randomly assigned to one of three groups, i.e. a sham instrumented (Sham) group, a sustained hemorrhagic shock (HS) group, and a hemorrhagic shock with resuscitation (HS/RES) group (n = 5 in each group). Controlled hemorrhagic shock was induced and the mean arterial pressure (MAP) was kept between 40-45 mmHg for sixty minutes in both HS and HS/RES groups. Then resuscitation with infusion of shed autologous blood and normal saline was performed in HS/RES group. Microdialysis probes were put in the liver and the right atrium for collection of serial samples. NO concentrations in dialysate samples were measured using chemiluminescence. Hepatic iNOS and GTPCH mRNA concentrations were analyzed using semiquantitative reverse transcription and polymerase chain reaction (RT-PCR). Hemorrhagic shock induced both the hepatic and circulating NO biosynthesis as well as hepatic iNOS mRNA expression. Resuscitation with shed blood/normal saline normalized this upregulation. However, no difference was found in mean hepatic GTPCH mRNA concentrations between groups in this experiment. We provide the evidence that hemorrhagic shock-induced NO biosynthesis involves upregulation of iNOS transcription in liver tissue and GTPCH transcription is unaffected by either hemorrhagic shock or resuscitation. Furthermore, microdialysis is an ideal technique for serial sampling and that events can be followed.
    No preview · Article · Oct 2002 · Acta anaesthesiologica Sinica