Peroxiredoxin 6 mediates the protective function of curcumin pretreatment in acute lung injury induced by serum from patients undergoing one-lung ventilation in vitro.

BACKGROUND: Curcumin has attracted much attention due to its wide range of therapeutic effects. In this study, we used serum collected from patients undergoing one-lung ventilation (OLV) to establish an in vitro acute lung injury (ALI) model to explore the potential protective mechanism of curcumin on ALI. Our study provides a new reference for the prevention and treatment of ALI induced by OLV. METHODS: A549 cells were treated with 20% serum from patients undergoing OLV to establish an in vitro ALI model. Curcumin, at a dose of 40 µg/ml, was administered two hours prior to this model. The levels of inflammation and oxidative stress markers were observed by Western blot, qRT-PCR, ELISA and reactive oxygen species assay. Additionally, the expression of peroxiredoxin 6 (Prdx6) and proteins involved in the NF-κB signaling pathway was evaluated. RESULTS: Twenty percent of serum collected from patients undergoing OLV downregulated the expression of Prdx6, leading to the activation of the NF-κB signaling pathway, which was associated with the subsequent overproduction of inflammatory cytokines and reactive oxygen species. Pretreatment with curcumin restored Prdx6 downregulation and inhibited NF-κB pathway activation by suppressing the nuclear translocation of P65, eventually reducing inflammation and oxidative stress damage in A549 cells. CONCLUSIONS: Prdx6 mediated the protective function of curcumin by inhibiting the activation of the NF-κB pathway in ALI in vitro.

Pharmacodynamic analysis of target-controlled infusion of propofol in patients with hepatic insufficiency.

The effect of liver dysfunction on target-controlled infusion (TCI) of propofol remains poorly documented. The pharmacodynamic performance of propofol TCI was evaluated in a cohort of Chinese patients with hepatic insufficiency. Fifty-three patients with hepatic insufficiency were enrolled in the current prospective, observational study. Anesthesia was induced with propofol via TCI to a plasma concentration of 3 µg/ml. Following loss of consciousness (LOC), fentanyl and cisatracurium were administered. Pharmacodynamic parameters were recorded during TCI, including time to LOC, bispectral index (BIS), heart rate (HR) and blood pressure. Patients were divided into two groups based on model of end stage liver disease (MELD) score: Those with a MELD score of ≤9 and those with a MELD score of ≥10. BIS, mean arterial pressure and HR were demonstrated to vary according to time, but were not affected by liver dysfunction. Hypotension was prominent in patients with a MELD score of ≥10 30 min after induction. The proportion of bradycardia and hypotension at the other time points was not significantly different between MELD scores of ≤9 and ≥10. Notably, no bradycardia was observed in MELD of ≥10. Thus, bradycardia and hypotension was observed in patients with hepatic insufficiency over time, although patients with different severities of hepatic insufficiency did not present with different depths of anesthesia. TCI of propofol to 3 µg/ml may be not suitable for patients with hepatic insufficiency, particularly those with severe liver dysfunction. Predictive concentrations (Cp) of TCI propofol requires further investigation and adjustment in patients with hepatic insufficiency (trial registration no. ChiCTR-OCH-12002255).

Intestinal injury following liver transplantation was mediated by TLR4/NF-κB activation-induced cell apoptosis.

Intestinal motility and barriers are often impaired due to intestinal congestion during liver transplantation. Intestinal bacteria and enterogenous endotoxins enter into the blood stream or lymphatic system and translocate to other organs, which can result in postoperative multi-organ dysfunction (MODF) and systemic inflammatory reaction syndrome (SIRS) severely affecting patient survival. However, the mechanisms underlying liver transplantation-induced intestinal injury remain unclear and effective therapies are lacking. Thus, the present study investigated whether these effects were associated with endotoxin-mediated apoptosis. Rat autologous orthotopic liver transplantation (AOLT) models were established to observe dynamic intestinal injuries at different time-points following reperfusion. Changes in the levels of endotoxins and the primary receptor, toll-like receptor 4 (TLR4), as well as its downstream signaling molecule, nuclear factor-κB (NF-κB) were all determined. Finally, immunohistochemistry and terminal deoxynucleotidyl transferase dUTP nick end labeling assays were conducted to detect caspase-3 expression and intestinal cell apoptosis, respectively. AOLT resulted in significant pathological intestinal injury, with the most serious intestine damage apparent four or eight hours following reperfusion. Furthermore, the levels of endotoxins and inflammatory cytokines, such as tumor necrosis factor-α and interleukin-6, peaked during this time period and gradually decreased to the normal level. Notably, TLR4 and downstream NF-κB expression, as well as NF-κB-mediated caspase-3 activation and intestinal cell apoptosis coincided with the intestinal pathological damage. Thus, the possible mechanism of post-liver transplantation intestinal injury was demonstrated to be associated with NF-κB activation-induced cell apoptosis.

Propofol pharmacokinetics in China: a multicentric study.

OBJECTIVE: A multicenter population pharmacokinetics study of propofol was performed to establish a new population model. MATERIALS AND METHODS: Three thousand two hundred and fifty-nine blood samples of 220 participants were measured by HPLC-UV or HPLC-FLU or GC-MS. Target-controlled infusion after single bolus or continuous infusion was applied for propofol anesthesia. The samples were taken from 2 to 1500 min. The concentration-time profiles were analyzed by nonlinear mixed effect model (NONMEM) with first order estimation method. The inter-individual variability and the residual variability were described by exponential model and constant coefficient variation model. The stepwise modeling strategy using PsN was applied for covariate modeling. The criteria of forward addition and backward elimination were (α = 0.01 and α = 0.005, χ(2), df = 1). The final model was evaluated by bootstrap using PDx and visual predictive check using PsN. 500 bootstraps and 1000 simulation were run. RESULT: The propofol population model was described by 3-compartment model with inter-individual variability of CL, V(1), Q(2,) and Q(3) describing by exponential model. The inter-individual variability of V(2), V(3) were not included because it is reported that the parameter was near its boundary. The typical value of CL, V1, Q2, V2, Q3 and V3 were 1.28 L · min(-1), 10.1 × (age/44)-0.465 × (1 + 0.352 × sex) L, 0.819 L · min(-1), 36.0 L, 0.405 × (bodyweight/60)1.58 L · min(-1) and 272 L, respectively. Coefficients of inter-individual variability of CL, V1, Q2 and Q3 were 30.5%, 35.6%, 43.7% and 66.9%, respectively, and the coefficients of variation of HPLC-UV, GC-MS and HPLC-FLU were 13.3%, 16.9% and 24.2%, respectively. The bootstrap evaluation showed that the final model parameter estimates were within ± 3.39% compared with bootstrap median. The curves of observations percentiles were distributed within the corresponding 95 prediction percentiles by the visual predictive check. CONCLUSION: The three-compartment model with first-order elimination could describe the pharmacokinetics of propofol fairly well. The involved fixed effects are age, body weight and sex. The population model was evaluated to be stable by bootstrap and visual predictive check.

[Population pharmacokinetic modeling and evaluation of propofol from multiple centers].

In order to successfully develop the effective population pharmacokinetic model to predict the concentration of propofol administrated intravenously, the data including the concentrations across both distribution and elimination phases from five hospitals were analyzed using nonlinear mixed effect model (NONMEM). Three-compartment pharmacokinetic model was applied while the exponential model was used to describe the inter-individual variability and constant coefficient model to the intra-individual variability, accordingly. Covariate effect including the body weight on the parameter CL, V1, Q2, V2, Q3 and V3 were investigated. The performance of final model was assessed by Bootstrapping, goodness-of-fit and visual predictive checking (VPC). The context-sensitive half-times and the infusion rates necessary to maintain the concentration of 1 microg x mL(-1) were simulated to six subpopulations. The results were as follows: the typical value of CL, V1, Q2, V2, Q3 and V3 were 0.965 x (1 + 0.401 x VESS) x (BW/59)(0.578) L x min(-1), 13.4 x (AGE/45)(-0.317) L, 0.659 x (1 + GENDER x 0.385) L x min(-1), 28.8 L, 0.575 x (1 + GENDER x 0.367) x (1 - 0.369 x VESS) L x min(-1) and 196 L respectively. Coefficients of the inter-individual variability of CL, V1, Q2, V2, Q3 and V3 were 29.2%, 46.9%, 35.2%, 40.4%, 67.0% and 49.9% respectively, and the coefficients of residual variability were 24.7%, 16.1% and 22.5%, the final model indicated a positive influence of a body weight on CL, and also that a negative correlation of age with V1. Q2 and Q3 in males were higher than those in females at 38.5% and 36.7%. The CL and Q3 were 40.1% increased and 36.9% decreased in arterial samples compared to those in venous samples. The determination coefficient of observations (DV)-individual predicted value (IPRED) by the final model was 0.91 which could predict the propofol concentration fairly well. The stability and the predictive performance were accepted by Bootstrapping, the goodness-of-fit and VPC. The context-sensitive half-times and infusion rates necessary to maintain the concentration of 1 microg x mL(-1) were different obviously among the 6 sub-populations obviously. The three-compartment model with first-order elimination could describe the pharmacokinetics of propofol fairly well. The involved fixed effects are age, body weight, gender and sampling site. The simulations in 6 subpopulations were available in clinical anesthesia. The propofol anesthesia monitor care could be improved by individualization of pharmacokinetic parameter estimated from the final model.

[Changes of hemodynamics and concentrations of nitric oxide, endothelin, prostacyclin, and thromboxane A2 during portal cavity clamping and opening in portal hypertensive canines].

OBJECTIVE: To observe the changes in systemic hemodynamics and their relations to the concentrations of nitric oxide, endothelin, prostacyclin, and thromboxane A2 after portal cavity clamping and opening in portal hypertensive canines. METHODS: Twelve canines were randomly divided into control group and model group, and partial ligation of the portal vein was performed in the model group. Portal cavity clamping and opening was performed 12 weeks later in the two groups. The hemodynamic parameters including cardiac output index (CI), heart rate (HR), mean artery blood pressure (MABP), central venous pressure (CVP), pulmonary arteriole wedge pressure (PAWP), and systemic vascular resistance index (SVRI) were measured during the operation. Samples were obtained from the central vein at 3 time points during the operation for measuring NO, ET, PGI2, and TXA2. RESULTS: Portal vein ligation and portal cavity clamping produced obvious changes in the systemic circulation of the dogs, and the alteration was milder in the control group. After obstruction of the portal vein, the NO levels in systemic circulation in portal hypertensive dogs declined obviously, but gradually recovered the normal level after reperfusion. CONCLUSION: Systemic circulation undergoes significant alterations after portal vein obstruction, but its changes in portal hypertensive dogs are milder than those in the control group, the mechanism of which needs further investigation.

Relationship between the expression of Toll-like receptor 2 and 4 in mononuclear cells and postoperative acute lung injury in orthotopic liver transplantation.

BACKGROUND: The aim of this study was to investigate the potential relationship between the dynamic expression of Toll-like receptor 2 and 4 (TLR2/4) in peripheral blood mononuclear cells as well as changes in serum concentration of inflammatory factors and acute lung injury (ALI) in patients after orthotopic liver transplantation (OLT). METHODS: The peripheral blood samples of 27 patients (23 men and 4 women with ASA III to IV) who received OLT were collected for measurement of TLR2/4 at T1 (after induction of anesthesia), T2 (25 minutes after anhepatic phase), T3 (3 hours after graft reperfusion) and T4 (24 hours after graft reperfusion). The expression of TLR2/4 in mononuclear cells was measured by flow cytometry. The serum concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-8 were measured by enzyme-linked immunosorbent assay (ELISA). Twenty-seven patients were assigned to ALI group (n = 9) and non-ALI group (n = 18) according to the diagnostic criteria of ALI. The expression of TLR2/4 in the ALI group or non-ALI group was analyzed. RESULTS: Compared to the non-ALI group, the volumes of blood loss, ascites, total output and transfused red blood cells were higher in the ALI group, and the anhepatic phase lasted longer (P < 0.05, P < 0.01). The expression of TLR2/4 in mononuclear cells increased significantly at T3 and T4, and serum concentrations of TNF-alpha, IL-1beta and IL-8 increased significantly too. There was no significant difference in Child-Turcotte-Pugh (CTP) scores between the ALI group and non-ALI group (P > 0.05). The expression of TLR2/4 in mononuclear cells increased significantly at T3 and T4 in the ALI group (P < 0.05, P < 0.01). A positive correlation was noted between the expression of TLR4 in mononuclear cells and the serum concentrations of TNF-alpha, IL-1beta (P = 0.041, P = 0.046) in the ALI group. In the non-ALI group, statistical results showed that the expression level of TLR2/4 in mononuclear cells was not significantly different during the peri-operative period of OLT (besides TLR4 expression at T4). Compared to the non-ALI group, the increasing amplitude of TLR2/4 expression in mononuclear cells was more significant in the ALI group. The patients whose TLR2/4 expression in mononuclear cells exceeded that at T1 by one time were more likely to suffer from ALI (P = 0.013), with a relative risk of 16. CONCLUSION: The expression level of TLR2/4 in mononuclear cells increases significantly in the peri-operative period of OLT, and it may be a high risk factor for occurrence of postoperative ALI.

[Significance of hemodynamic changes and monitoring value of patients with severe hepatitis during perioperative orthotopic liver transplantation].

OBJECTIVE: To observe the hemodynamic changes of the patients with severe hepatitis during orthotopic liver transplantation (OLT). METHODS: Ten patients with severe hepatitis received liver transplantation. The pulmonary artery catheter was inserted into right jugular vein and an arterial line was put in the left radial artery. Hemodynamics parameters including cardiac output (CO), arterial blood pressure (ABP), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), cardiac index (CI) at different time points were observed. RESULTS: During the operation, HR was increased, and ABP was significantly decreased at the beginning of anhepatic period and neo-hepatic period. Central venous pressure (CVP) was significantly decreased during anhepatic period and profoundly increased in the early neo-hepatic phase, then declined to normal range progressively. Pulmonary capillary wedge pressure (PCWP) changed in accordance with the variation of pulmonary arterial pressure (PAP). Both of them were significantly decreased during anhepatic period and profoundly increased in the early neo-hepatic phase. SVR was at a lower level before operation, and gradually increased during anhepatic period, then significantly declined at the beginning of anhepatic period. PVR had the most marked changes during the neo-hepatic period, gradually decreased to the pre-operation level after significant elevation at the early neo-hepatic phase. Left ventricular stroke work index (LVSWI) was profoundly declined from the beginning of anhepatic period to the 1 minute after neo-hepatic phase, then progressively increased. Right ventricular stroke work index (RVSWI) was significantly decreased during anhepatic period, then progressively increased during neo-hepatic period. CO and CI maintained at a higher level, significantly declined during anhepatic period compared with pre-anhepatic period and gradually increased to a higher level than peri-operation. CONCLUSION: Remarkable changes in hemodynamics of patients with severe hepatitis during liver transplantation are found especially at the early phase of anhepatic and neo-hepatic, while CO maintained at a higher level, together with a complicated changes in SVRI. Monitoring hemodynamics during peri-operation has its value to prevent and manage cardiac insufficiency and low blood volume.