Dexmedetomidine Pretreatment Protects Against Myocardial Ischemia/Reperfusion Injury by Activating STAT3 Signaling.

BACKGROUND: Myocardial infarction is a common perioperative complication, and blood flow restoration causes ischemia/reperfusion injury (IRI). Dexmedetomidine (DEX) pretreatment can protect against cardiac IRI, but the mechanism is still insufficiently understood. METHODS: In vivo, myocardial ischemia/reperfusion (30 minutes/120 minutes) was induced via ligation and then reperfusion of the left anterior descending coronary artery (LAD) in mice. Intravenous infusion of 10 µg/kg DEX was performed 20 minutes before ligation. Moreover, the α2-adrenoreceptor antagonist Yohimbine and STAT3 inhibitor Stattic were applied 30 minutes ahead of DEX infusion. In vitro, hypoxia/reoxygenation (H/R) with DEX pretreatment for 1 hour was performed in isolated neonatal rat cardiomyocytes. In addition, Stattic was applied before DEX pretreatment. RESULTS: In the mouse cardiac ischemia/reperfusion model, DEX pretreatment lowered the serum creatine kinase-MB isoenzyme (CK-MB) levels (2.47 ± 0.165 vs 1.55 ± 0.183; P < .0001), downregulated the inflammatory response ( P ≤ .0303), decreased 4-hydroxynonenal (4-HNE) production and cell apoptosis ( P = .0074), and promoted the phosphorylation of STAT3 (4.94 ± 0.690 vs 6.68 ± 0.710, P = .0001), which could be blunted by Yohimbine and Stattic. The bioinformatic analysis of differentially expressed mRNAs further confirmed that STAT3 signaling might be involved in the cardioprotection of DEX. Upon H/R treatment in isolated neonatal rat cardiomyocytes, 5 µM DEX pretreatment improved cell viability ( P = .0005), inhibited reactive oxygen species (ROS) production and calcium overload (both P ≤ .0040), decreased cell apoptosis ( P = .0470), and promoted STAT3 phosphorylation at Tyr705 (0.102 ± 0.0224 vs 0.297 ± 0.0937; P < .0001) and Ser727 (0.586 ± 0.177 vs 0.886 ± 0.0546; P = .0157), which could be abolished by Stattic. CONCLUSIONS: DEX pretreatment protects against myocardial IRI, presumably by promoting STAT3 phosphorylation via the α2-adrenoreceptor in vivo and in vitro.

Dexmedetomidine Alleviates Gut-Vascular Barrier Damage and Distant Hepatic Injury Following Intestinal Ischemia/Reperfusion Injury in Mice.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) challenge often results in gut barrier dysfunction and induces distant organ injury. Dexmedetomidine has been shown to protect intestinal epithelial barrier against I/R attack. The present study aims to investigate the degree to which intestinal I/R attack will contribute to gut-vascular barrier (GVB) damage, and to examine the ability of dexmedetomidine to minimize GVB and liver injuries in mice. METHODS: In vivo, intestinal ischemic challenge was induced in mice by clamping the superior mesenteric artery for 45 minutes. After clamping, the mice were subjected to reperfusion for either 2, 4, 6, or 12 hours. Intraperitoneal injection of dexmedetomidine 15, 20, or 25 µg·kg-1 was performed intermittently at the phase of reperfusion. For the in vitro experiments, the challenge of oxygen-glucose deprivation/reoxygenation (OGD/R) was established in cultured vascular endothelial cells, and dexmedetomidine (1 nM) was used to treat the cells for 24 hours. Moreover, in vivo and in vitro, SKL2001 (a specific agonist of ß-catenin) or XAV939 (a specific inhibitor of ß-catenin) was applied to determine the role of ß-catenin in the impacts provided by dexmedetomidine. RESULTS: The attack of intestinal I/R induced GVB damage. The greatest level of damage was observed at 4 hours after intestinal reperfusion. There was a significant increase in plasmalemma vesicle-associated protein-1 (PV1, a specific biomarker for endothelial permeability) expression (5.477 ± 0.718 vs 1.000 ± 0.149; P < .001), and increased translocation of intestinal macromolecules and bacteria to blood and liver tissues was detected (all P < .001). Liver damages were observed. There were significant increases in histopathological scores, serum parameters, and inflammatory factors (all P < .001). Dexmedetomidine 20 µg·kg-1 reduced PV1 expression (0.466 ± 0.072 vs 1.000 ± 0.098; P < .001) and subsequent liver damages (all P < .01). In vitro, dexmedetomidine significantly improved vascular endothelial cell survival (79.387 ± 6.447% vs 50.535 ± 1.766%; P < .001) and increased the productions of tight junction protein and adherent junction protein (all P < .01) following OGD/R. Importantly, in cultured cells and in mice, ß-catenin expression significantly decreased (both P < .001) following challenge. Dexmedetomidine or SKL2001 upregulated ß-catenin expression and produced protective effects (all P < .01). However, XAV939 completely eliminated the protective effects of dexmedetomidine on GVB (all P < .001). CONCLUSIONS: The disruption of GVB occurred following intestinal I/R. Dexmedetomidine alleviated I/R-induced GVB impairment and subsequent liver damage.

HMGB1 signaling-regulated endoplasmic reticulum stress mediates intestinal ischemia/reperfusion-induced acute renal damage.

BACKGROUND: Ischemia/reperfusion of the intestine often leads to distant organ injury, but the mechanism of intestinal ischemia/reperfusion-induced renal dysfunction is still not clear. The present study aimed to investigate the mechanisms of acute renal damage after intestinal ischemia/reperfusion challenge and explore the role of released high-mobility group box-1 in this process. METHODS: Intestinal ischemia/reperfusion was induced in male Sprague-Dawley rats by clamping the superior mesenteric artery for 1.5 hours. At different reperfusion time points, anti-high-mobility group box-1 neutralizing antibodies or ethyl pyruvate were administered to neutralize or inhibit circulating high-mobility group box-1, respectively. RESULTS: Significant kidney injury was observed after 6 hours of intestinal reperfusion, as indicated by increased serum levels of urea nitrogen and creatinine, increased expression of neutrophil gelatinase-associated lipocalin, interleukin-6, and MIP-2, and enhanced cell apoptosis, as indicated by cleaved caspase 3 levels in renal tissues. The levels of phosphorylated eIF2ɑ, activating transcription factor 4, and C/EBP-homologous protein (CHOP) were markedly elevated, indicating the activation of endoplasmic reticulum stress in the impaired kidney. High-mobility group box-1 translocated to cytoplasm in the intestine and serum concentrations of high-mobility group box-1 increased notably during the reperfusion phase. Both anti-high-mobility group box-1 antibodies and ethyl pyruvate treatment significantly reduced serum high-mobility group box-1 concentrations, attenuated endoplasmic reticulum stress in renal tissue and inhibited the development of renal damage. Moreover, the elevated expression of receptor for advanced glycation end products in the kidneys after intestinal ischemia/reperfusion was abrogated after high-mobility group box-1 inhibition. CONCLUSION: These results suggested that high-mobility group box-1 signaling regulated endoplasmic reticulum stress and promoted intestinal ischemia/reperfusion-induced acute kidney injury. High-mobility group box-1 neutralization/inhibition might serve as a pharmacological intervention strategy for these pathophysiological processes.

Terlipressin relieves intestinal and renal injuries induced by acute mesenteric ischemia via PI3K/Akt pathway.

Background: To date, the effect of vasopressin on organ damages after acute mesenteric ischemia (MI) remains poorly understood. Aims: To investigate the effect of terlipressin, a selective vasopressin V1 receptor agonist, versus norepinephrine on the intestinal and renal injuries after acute MI, and to explore the underlying mechanism of terlipressin. Methods: Acute MI model was produced by clamping the superior mesenteric artery for 1 hour. Immediately after unclamping, terlipressin or norepinephrine was intravenously administered for 2 hours. Meanwhile, in vitro, RAW264.7 cells were treated with lipopolysaccharide or lipopolysaccharide+terlipressin. In addition, wortmannin was used to determine the role of phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt) pathway in the potential impacts of terlipressin. Results: MI led to severe hypotension, caused notable intestinal and renal impairments and resulted in high mortality, which were markedly improved by terlipressin or norepinephrine. Terlipressin increased mean arterial pressure, decreased intestinal epithelial cell apoptosis, inhibited the generation of M1 macrophage in intestinal and renal tissues, and hindered the release of inflammatory cytokines after MI. Moreover, in cultured macrophages, terlipressin reduced the mRNA level of specific M1 markers and the release of inflammatory cytokines caused by lipopolysaccharide challenge. Wortmannin decreased the expression of PI3K and Akt induced by terlipressin in cells and in tissues, and abolished the above protective effects conferred by terlipressin. Conclusions: Terlipressin or norepinephrine could effectively improve organ damages and mortality after acute MI. Terlipressin elevates blood pressure and inhibits intestinal epithelial apoptosis and macrophage M1 polarization via the PI3K/Akt pathway.

Tumor necrosis as a poor prognostic predictor on postoperative survival of patients with solitary small hepatocellular carcinoma.

BACKGROUND: Small hepatocellular carcinoma (sHCC) is a special subtype of HCC with the maximum tumor diameter ≤ 3 cm and excellent long-term outcomes. Surgical resection or radiofrequency ablation provides the greatest chance for cure; however, many patients still undergo tumor recurrence after primary treatment. To date, there is no clinical applicable method to assess biological aggressiveness in solitary sHCC. METHODS: In the current study, we retrospectively evaluated tumor necrosis of 335 patients with solitary sHCC treated with hepatectomy between December 1998 and 2010 from Sun Yat-sen University Cancer Center. RESULTS: The presence of tumor necrosis was observed in 157 of 335 (46.9%) sHCC patients. Further correlation analysis showed that tumor necrosis was significantly correlated with tumor size and vascular invasion (P = 0.026, 0.003, respectively). The presence of tumor necrosis was associated closely with poorer cancer-specific overall survival (OS) and recurrence-free survival (RFS) as evidenced by univariate (P <  0.001; hazard ratio, 2.821; 95% CI, 1.643-4.842) and multivariate analysis (P = 0.005; hazard ratio, 2.208; 95% CI, 1.272-3.833). Notably, the combined model by tumor necrosis, vascular invasion and tumor size can significantly stratify the risk for RFS and OS and improve the ability to discriminate sHCC patients' outcomes (P <  0.0001 for both). CONCLUSIONS: Our results provide evidence that tumor necrosis has the potential to be a parameter for cancer aggressiveness in solitary sHCC. The combined prognostic model may be a useful tool to identify solitary sHCC patients with worse outcomes.

Impact of Anxiety or Depression Symptoms on Propofol Requirements for Sedation in Females: A Prospective Cohort Study.

Mental disorders are thought to affect various clinical outcomes during the perioperative period. Among them, anxiety and depression are 2 of the most common types. However, the impacts of anxiety or depression on propofol requirements remain unclear. This study aimed to investigate the effects of anxiety or depression symptoms on the propofol requirements for sedation in females. This study recruited female patients aged 18 to 65 years, with American Society of Anesthesiologists physical status classification of 1 to 2, who were scheduled for hysteroscopic surgery under propofol-based intravenous anesthesia. The day before surgery, the Hospital Anxiety and Depression Scale (HADS) was used to assess the symptoms of anxiety and depression within the past 6 months. Target-controlled propofol was gradually titrated to achieve 3 desired levels of sedation: Modified Observer's Assessment of Alertness/Sedation scale (MOAA/S) score 3, MOAA/S score 1, and MOAA/S score 1 and Narcotrend Index <65. The effect-site concentration of propofol correlated with HADS-Anxiety scores for the sedation levels of MOAA/S 3 and 1 (r = .249, P = .008; and r = .190, P = .045, respectively). However, the propofol requirements did not correlate with HADS-Depression scores at any sedation level. In conclusion, female patients with anxiety symptoms, but not depression symptoms, required a higher dose of propofol for sedation in hysteroscopy.

Intraoperative ventilation strategies to prevent postoperative pulmonary complications: a network meta-analysis of randomised controlled trials.

BACKGROUND: The debate on lung-protective ventilation strategies for surgical patients is ongoing. Evidence suggests that the use of low tidal volume VT improves clinical outcomes. However, the optimal levels of PEEP and recruitment manoeuvre (RM) strategies incorporated into low VT ventilation remain unclear. METHODS: Several electronic databases were searched to identify RCTs that focused on comparison between low VT strategy and conventional mechanical ventilation (CMV), or between two different low VT strategies in surgical patients. The primary outcome was postoperative pulmonary complications (PPCs). The secondary outcomes were atelectasis, pneumonia, acute respiratory distress syndrome, and short-term mortality. Bayesian network meta-analyses were performed using WinBUGS. The odds ratios (ORs) and corresponding 95% credible intervals (CrIs) were estimated. RESULTS: Compared with CMV, low VT ventilation with moderate-to-high PEEP reduced the risk of PPCs (moderate PEEP [5-8 cm H2O]: OR 0.50 [95% CrI: 0.28, 0.89]; moderate PEEP+RMs: 0.39 [0.19, 0.78]; and high PEEP [≥9 cm H2O]+RMs: 0.34 [0.14, 0.79]). Low VT ventilation with moderate-to-high PEEP and RMs also specifically reduced the risk of atelectasis compared with CMV (moderate PEEP+RMs: OR 0.36 [95% CrI: 0.16, 0.87]; and high PEEP+RMs: 0.41 [0.15, 0.97]), whilst low VT ventilation with moderate PEEP was superior to CMV in reducing the risk of pneumonia (OR 0.46 [95% CrI: 0.15, 0.94]). CONCLUSIONS: The combination of low VT ventilation and moderate-to-high PEEP (≥5 cm H2O) seems to confer lung protection in surgical patients undergoing general anaesthesia. CLINICAL TRIAL REGISTRATION: PROSPERO (CRD42019144561).

Gut Barrier Dysfunction Induced by Aggressive Fluid Resuscitation in Severe Acute Pancreatitis is Alleviated by Necroptosis Inhibition in Rats.

Fluid resuscitation is the first-line antishock treatment in severe acute pancreatitis (SAP). Currently, although mentions of complications related to aggressive fluid resuscitation are very frequent, a lack of proper handling of complications remains. One of the most important complications is intestinal barrier injury, including intestinal ischemia-reperfusion injury following aggressive fluid resuscitation. Once injured, the intestinal barrier may serve as the source of additional diseases, including systemic inflammatory response syndrome and multiple organ dysfunction syndrome, which aggravate SAP. This study focused on the underlying mechanisms of gut barrier dysfunction in rats induced by aggressive fluid resuscitation in SAP. This study further indicated the important role of necroptosis in intestinal barrier injury which could be relieved by using necroptosis-specific inhibitor Nec-1 before aggressive fluid resuscitation, thus reducing intestinal barrier damage. We also found pancreas damage after intestinal ischemia/reperfusion challenge and indicated the effects of high mobility group protein B1 in the vicious cycle between SAP and intestinal barrier damage.

Is goal-directed fluid therapy based on dynamic variables alone sufficient to improve clinical outcomes among patients undergoing surgery? A meta-analysis.

BACKGROUND: Whether goal-directed fluid therapy based on dynamic predictors of fluid responsiveness (GDFTdyn) alone improves clinical outcomes in comparison with standard fluid therapy among patients undergoing surgery remains unclear. METHODS: PubMed, EMBASE, the Cochrane Library and ClinicalTrials.gov were searched for relevant studies. Studies comparing the effects of GDFTdyn with that of standard fluid therapy on clinical outcomes among adult patients undergoing surgery were considered eligible. Two analyses were performed separately: GDFTdyn alone versus standard fluid therapy and GDFTdyn with other optimization goals versus standard fluid therapy. The primary outcomes were short-term mortality and overall morbidity, while the secondary outcomes were serum lactate concentration, organ-specific morbidity, and length of stay in the intensive care unit (ICU) and in hospital. RESULTS: We included 37 studies with 2910 patients. Although GDFTdyn alone lowered serum lactate concentration (mean difference (MD) - 0.21 mmol/L, 95% confidence interval (CI) (- 0.39, - 0.03), P = 0.02), no significant difference was found between groups in short-term mortality (odds ratio (OR) 0.85, 95% CI (0.32, 2.24), P = 0.74), overall morbidity (OR 1.03, 95% CI (0.31, 3.37), P = 0.97), organ-specific morbidity, or length of stay in the ICU and in hospital. Analysis of trials involving the combination of GDFTdyn and other optimization goals (mainly cardiac output (CO) or cardiac index (CIx)) showed a significant reduction in short-term mortality (OR 0.45, 95% CI (0.24, 0.85), P = 0.01), overall morbidity (OR 0.41, 95% CI (0.28, 0.58), P < 0.00001), serum lactate concentration (MD - 0.60 mmol/L, 95% CI (- 1.04, - 0.15), P = 0.009), cardiopulmonary complications (cardiac arrhythmia (OR 0.58, 95% CI (0.37, 0.92), P = 0.02), myocardial infarction (OR 0.35, 95% CI (0.16, 0.76), P = 0.008), heart failure/cardiovascular dysfunction (OR 0.31, 95% CI (0.14, 0.67), P = 0.003), acute lung injury/acute respiratory distress syndrome (OR 0.13, 95% CI (0.02, 0.74), P = 0.02), pneumonia (OR 0.4, 95% CI (0.24, 0.65), P = 0.0002)), length of stay in the ICU (MD - 0.77 days, 95% CI (- 1.07, - 0.46), P < 0.00001) and in hospital (MD - 1.18 days, 95% CI (- 1.90, - 0.46), P = 0.001). CONCLUSIONS: It was not the optimization of fluid responsiveness by GDFTdyn alone but rather the optimization of tissue and organ perfusion by GDFTdyn and other optimization goals that benefited patients undergoing surgery. Patients managed with the combination of GDFTdyn and CO/CI goals might derive most benefit.

Association of pre-operative troponin levels with major adverse cardiac events and mortality after noncardiac surgery: A systematic review and meta-analysis.

BACKGROUND: Circulating cardiac troponin levels are powerful predictors of prognosis in many clinical settings, but their association with outcomes after noncardiac surgery is unclear. OBJECTIVES: The aim of this systematic review was to summarise current evidence on the association of pre-operative troponin elevation with postoperative major adverse cardiac events (MACE) and mortality in patients undergoing noncardiac surgery. DESIGN: Systematic review of observational studies with meta-analysis. DATA SOURCES: PubMed, EMBASE and Science Citation Index Expanded (ISI Web of Science) from their inception to 1 October 2017. ELIGIBILITY CRITERIA: Observational studies reporting the associations between pre-operative troponin levels and MACE and all-cause mortality after noncardiac surgeries were included. RESULTS: Ten studies met the eligibility criteria. The entire body of evidence addressing the research question was based on a total of 10 371 patients: 4.7 to 68.3% (median 23.8%) of patients had elevated troponin levels before surgery. Elevated pre-operative troponin was significantly associated with short-term MACE (seven studies, 5180 patients: odds ratio (OR) 6.92, 95% confidence interval (CI) 3.85 to 12.42), short-term mortality (five studies, 6103 patients: OR 4.23, 95% CI 2.27 to 7.89) and long-term mortality (two studies, 760 patients: OR 2.51, 95% CI 1.47 to 4.29). The associations remained significant when only multivariate-adjusted results were analysed. Overall, the reviewers' certainty about the summary estimates of the associations was very low. CONCLUSION: Current evidence suggests that pre-operative high troponin levels are significantly associated with adverse cardiac events and mortality after noncardiac surgery. TRIAL REGISTRATION: This systematic review was registered in the International Prospective Register of Systematic Reviews (Centre for Reviews and Dissemination 42017077837).

Synergistic effects of ischemic preconditioning and immediate post-conditioning in the protection against ischemia/reperfusion injury in rabbit submandibular glands.

Submandibular gland autotransplantation is an effective approach for treating severe keratoconjunctivitis sicca. However, ischemia/reperfusion (I/R) injury, which inevitably occurs during transplantation, is involved in the hypofunction and structural damage that occur early after transplantation. Therefore, it is critical to identify effective strategies to ameliorate I/R injury in submandibular glands. In this study, we investigated the ability of immediate post-conditioning combined with ischemic preconditioning to attenuate I/R injury. We observed that after I/R injury, the level of reactive oxygen species was increased, inflammatory response was strengthened, and severe apoptosis had occurred. In addition, the salivary flow rate was greatly decreased. However, the pathogenesis of I/R injury was significantly ameliorated by ischemia post-conditioning or ischemia preconditioning treatments. In addition, the combination of ischemia preconditioning and post-conditioning achieved synergistic protective effects against I/R injury compared with ischemia preconditioning or ischemia post-conditioning alone. The secretion function was restored in the combination group. Furthermore, the combination treatment involved the same mechanisms of ischemia preconditioning or ischemia post-conditioning, including suppression of the inflammatory reaction and neutrophil accumulation, attenuation of oxidation stress, and inhibition of apoptosis. In conclusion, the combination of ischemia preconditioning and ischemia post-conditioning treatment is a simple and effective approach for treating I/R injury in submandibular glands.

Propofol Does Not Reduce Pyroptosis of Enterocytes and Intestinal Epithelial Injury After Lipopolysaccharide Challenge.

BACKGROUND: To date, mechanisms of sepsis-induced intestinal epithelial injury are not well known. P2X7 receptor (P2X7R) regulates pyroptosis of lymphocytes, and propofol is usually used for sedation in septic patients. AIMS: We aimed to determine the occurrence of enterocyte pyroptosis mediated by P2X7R and to explore the effects of propofol on pyroptosis and intestinal epithelial injury after lipopolysaccharide (LPS) challenge. METHODS: A novel regimen of LPS challenge was applied in vitro and in vivo. Inhibitors of P2X7R (A438079) and NLRP3 inflammasome (MCC950), and different doses of propofol were administered. The caspase-1 expression, caspase-3 expression, caspase-11 expression, P2X7R expression and NLRP3 expression, extracellular ATP concentration and YO-PRO-1 uptake, and cytotoxicity and HMGB1 concentration were detected to evaluate enterocyte pyroptosis in cultured cells and intestinal epithelial tissues. Chiu's score, diamine oxidase and villus length were used to evaluate intestinal epithelial injury. Moreover, survival analysis was performed. RESULTS: LPS challenge activated caspase-11 expression and P2X7R expression, enhanced ATP concentration and YO-PRO-1 uptake, and led to increased cytotoxicity and HMGB1 concentration. Subsequently, LPS resulted in intestinal epithelial damage, as evidenced by increased levels of Chiu's score and diamine oxidase, and shorter villus length and high mortality of animals. A438079, but not MCC950, significantly relieved LPS-induced enterocyte pyroptosis and intestinal epithelial injury. Importantly, propofol did not confer the protective effects on enterocyte pyroptosis and intestinal epithelia although it markedly decreased P2X7R expression. CONCLUSION: LPS attack leads to activation of caspase-11/P2X7R and pyroptosis of enterocytes. Propofol does not reduce LPS-induced pyroptosis and intestinal epithelial injury, although it inhibits P2X7R upregulation.

TGF-ß1 improves mucosal IgA dysfunction and dysbiosis following intestinal ischaemia-reperfusion in mice.

Intestinal ischaemia/reperfusion (I/R) severely disrupts gut barriers and leads to high mortality in the critical care setting. Transforming growth factor (TGF)-ß1 plays a pivotal role in intestinal cellular and immune regulation. However, the effects of TGF-ß1 on intestinal I/R injury remain unclear. Thus, we aimed to investigate the effects of TGF-ß1 on gut barriers after intestinal I/R and the molecular mechanisms. Intestinal I/R model was produced in mice by clamping the superior mesenteric artery for 1 hr followed by reperfusion. Recombinant TGF-ß1 was intravenously infused at 15 min. before ischaemia. The results showed that within 2 hrs after reperfusion, intestinal I/R disturbed intestinal immunoglobulin A class switch recombination (IgA CSR), the key process of mucosal IgA synthesis, and resulted in IgA dysfunction, as evidenced by decreased production and bacteria-binding capacity of IgA. Meanwhile, the disruptions of intestinal microflora and mucosal structure were exhibited. Transforming growth factor-ß1 activated IgA CSR as evidenced by the increased activation molecules and IgA precursors. Strikingly, TGF-ß1 improved intestinal mucosal IgA dysfunction, dysbiosis and epithelial damage at the early stage after reperfusion. In addition, SB-431542, a specific inhibitor of activating mothers against decapentaplegic homologue (SMAD) 2/3, totally blocked the inductive effect of TGF-ß1 on IgA CSR and almost abrogated the above protective effects on intestinal barriers. Taken together, our study demonstrates that TGF-ß1 protects intestinal mucosal IgA immunity, microbiota and epithelial integrity against I/R injury mainly through TGF-ß receptor 1/SMAD 2/3 pathway. Induction of IgA CSR may be involved in the protection conferred by TGF-ß1.

Remifentanil preconditioning protects the small intestine against ischemia/reperfusion injury via intestinal δ- and µ-opioid receptors.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) injury can cause a high rate of mortality in the perioperative period. Remifentanil has been reported to provide protection for organs against I/R injury. We hypothesized that remifentanil preconditioning would attenuate the small intestinal injury induced by intestinal I/R. METHODS: We used both an in vivo rat model of intestinal I/R injury and a cell culture model using IEC-6 cells (the rat intestinal epithelial cell line) subjected to oxygen and glucose deprivation (OGD). Remifentanil was administered before ischemia or OGD, and 3 specific opioid receptors antagonists, naltrindole (a δ-OR selective antagonist), nor-binaltorphimine (nor-BNI, a κ-OR selective antagonist), and CTOP (a µ-OR selective antagonist), were administered before preconditioning to determine the role of opioid receptors in the intestinal protection mediated by remifentanil. RESULTS: In the in vivo rat model, intestinal I/R induced obvious intestinal injury as evidenced by increases in the Chiu score, serum diamine oxidase activity, the apoptosis index, and the level of cleaved caspase-3 protein expression, whereas remifentanil preconditioning significantly improved these changes in vivo. In the in vitro cell culture exposed to OGD, cell viability (MTT, ie, (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay and flow cytometric analysis showed that remifentanil preconditioning enhanced IEC-6 cell viability and decreased apoptosis. In both in vitro and in vivo models, the aforementioned protective effects of remifentanil preconditioning were abolished completely by previous administration of the δ- or µ-opioid markedly attentuated but not the κ-opioid receptor antagonist. CONCLUSION: Remifentanil preconditioning appears to act via δ- and µ-opioid receptors to protect the small intestine from intestinal I/R injury by attenuating apoptosis of the intestinal mucosal epithelial cells.

Decreased PD-1/PD-L1 Expression Is Associated with the Reduction in Mucosal Immunoglobulin A in Mice with Intestinal Ischemia Reperfusion.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) disrupts intestinal mucosal integrity and immunoglobulin A (IgA) generation. It has recently been shown that the programmed cell death-1 receptor (PD-1) plays a crucial role in regulating intestinal secreted IgA (sIgA). AIMS: To evaluate changes in PD-1 and PD-ligand 1 (PD-L1) expression on Peyer's patches (PP) CD4(+) T cells and to investigate the correlation between PD-1/PD-L1 and intestinal IgA production/mucosal integrity in mice following intestinal I/R. METHODS: I/R injury was induced by clamping the superior mesenteric artery for 1 h followed by 2-h reperfusion. PD-1/PD-L1 expression on PP CD4(+) T cells was measured in I/R and sham-operated mice. Additionally, transforming growth factor-ß1 (TGF-ß1) and interleukin-21 (IL-21) mRNA in CD4(+) T cells and IgA(+) and IgM(+) in PP B cells, as well as intestinal mucosal injury and sIgA levels, were assessed. RESULTS: PD-1/PD-L1, TGF-ß1, and IL-21 expression was down-regulated after intestinal I/R. Furthermore, IgA(+) B cells decreased and IgM(+) B cells increased in mice with intestinal I/R. Importantly, decreased PD-1/PD-L1 expression was correlated with increased mucosal injury and decreased IgA levels, as well as with decreased TGF-ß1 and IL-21 expression. CONCLUSIONS: Intestinal I/R inhibits PD-1/PD-L1 expression on PP CD4(+) T cells, which was associated with an impaired intestinal immune system and mechanical barriers. Our study indicates that PD-1/PD-L1 expression on CD4(+) T cells may be involved in the pathogenesis of intestinal I/R injury.

Treatment with Recombinant Trichinella spiralis Cathepsin B-like Protein Ameliorates Intestinal Ischemia/Reperfusion Injury in Mice by Promoting a Switch from M1 to M2 Macrophages.

Intestinal ischemia/reperfusion (I/R) injury, in which macrophages play a key role, can cause high morbidity and mortality. The switch from classically (M1) to alternatively (M2) activated macrophages, which is dependent on the activation of STAT6 signaling, has been shown to protect organs from I/R injuries. In the current study, the effects of recombinant Trichinella spiralis cathepsin B-like protein (rTsCPB) on intestinal I/R injury and the potential mechanism related to macrophage phenotypes switch were investigated. In a mouse I/R model undergoing 60-min intestinal ischemia followed by 2-h or 7-d reperfusion, we demonstrated that intestinal I/R caused significant intestinal injury and induced a switch from M2 to M1 macrophages, evidenced by a decrease in levels of M2 markers (arginase-1 and found in inflammatory zone protein), an increase in levels of M1 markers (inducible NO synthase and CCR7), and a decrease in the ratio of M2/M1 macrophages. RTsCPB reversed intestinal I/R-induced M2-M1 transition and promoted M1-M2 phenotype switch evidenced by a significant decrease in M1 markers, an increase in M2 markers, and the ratio of M2/M1 macrophages. Meanwhile, rTsCPB significantly ameliorated intestinal injury and improved intestinal function and survival rate of animals, accompanied by a decrease in neutrophil infiltration and an increase in cell proliferation in the intestine. However, a selective STAT6 inhibitor, AS1517499, reversed the protective effects of rTsCPB by inhibiting M1 to M2 transition. These findings suggest that intestinal I/R injury causes a switch from M2 to M1 macrophages and that rTsCPB ameliorates intestinal injury by promoting STAT6-dependent M1 to M2 transition.

Pseudoepitheliomatous hyperplasia mimicking invasive squamous cell carcinoma in extranodal natural killer/T-cell lymphoma: a report of 34 cases.

AIMS: Pseudoepitheliomatous hyperplasia (PEH) is defined as a pattern of epidermal reaction. However, it has not yet been extensively documented in extranodal natural killer/T-cell lymphoma (ENKTL). The aim of our study was to analyse a series of ENKTLs concomitant with PEH mimicking squamous cell carcinoma (SCC). METHODS AND RESULTS: We analysed 34 cases of ENKTL with PEH. In our study, the incidence of PEH was 3.8% in ENKTLs diagnosed over a 13-year period. All 34 cases presented with PEH, appearing as tongue-like projections of squamous epithelium into the underlying submucosa/dermis with variable depths and jagged borders. The keratinocytes sometimes showed a minor degree of cytological atypia, mostly in the stratum basale, and keratinocyte necrosis was absent. Atypical mitoses and a high nuclear/cytoplasmic ratio were absent. The submucosa and the squamous cell cords were also permeated by atypical lymphocytes. CONCLUSIONS: ENKTL can be associated with PEH, and the atypical lymphoid cell population can be highly subtle, and therefore may be easily mistaken for SCC, leading to inappropriate therapy. A correct diagnosis requires awareness and recognition of this pitfall by recognizing the associated conditions listed above, which distinguish PEH from SCC.

Anesthetic manipulation in extreme airway stenosis: a case report.

INTRODUCTION: Anesthetic management with airway stenosis is challenging. Techniques for maintaining spontaneous respiration are required under sedative and analgesic conditions. CASE PRESENTATION: A 35-year-old Chinese woman presented to our hospital with difficulty breathing. Computerized tomography showed a tumor in the frontal area of her neck, which was causing extreme narrowing of her trachea. She was immediately scheduled for emergency surgery to remove the tumor. Fiberscopic intubation was carefully performed with dexmedetomidine sedation and remifentanil analgesia. Spontaneous respiration was successfully maintained. CONCLUSION: In cases of extreme airway stenosis, intubation can be safely achieved with dexmedetomidine sedation and remifentanil analgesia.

The incidence and risk factors of gastrointestinal complications after hepatectomy: a retrospective observational study of 1329 consecutive patients in a single center.

BACKGROUND: Despite of the importance of gastrointestinal (GI) complications in morbidity and mortality after major and moderate surgeries, it is not yet specifically studied in patients undergoing hepatectomy. This study was aimed to investigate the in-hospital incidence and potential risk factors of GI complications after open hepatectomy in our hospital. SUBJECTS AND METHODS: Prospectively recorded perioperative data from 1329 patients undergoing elective hepatectomy were retrospectively reviewed. The in-hospital incidence of GI complications was investigated, and independent risk factors were analyzed by multiple logistic regression. RESULTS: GI complications occurrence was 46.4%. Univariate analysis showed that preoperative Child-Pugh score, total bilirubin, aspartate transaminase, anesthesia duration, operation duration, intraoperative blood loss, crystalloid and colloid infusion, blood transfusion, urine output, use of Pringle maneuver were statistically different between patients with and without GI complications (P < 0.05). Moreover, patients with GI complications had a more prolonged postoperative parenteral nutrient supporting time, hospital stay and ICU stay, and higher incidence of other complications than those without GI complications (P < 0.05). Multivariate regression indicated that long duration of anesthesia (odds ratio 2.51, P < 0.001) and use of Pringle maneuver (odds ratio 1.37, P = 0.007) were independent risk factors of GI complications after hepatectomy. CONCLUSIONS: The incidence of GI complications after hepatectomy is high, which is related to an increase of other complications and a prolonged hospital stay. Avoidance of routinely use of Pringle maneuver and shortening the duration of anesthesia are important measures to reduce the postoperative GI complications.

Clinical benefits of dexmedetomidine versus propofol in adult intensive care unit patients: a meta-analysis of randomized clinical trials.

BACKGROUND: This meta-analysis was performed to assess the influence of dexmedetomidine and propofol for adult intensive care unit (ICU) sedation, with respect to patient outcomes and adverse events. MATERIALS AND METHODS: A systematic review was conducted of all randomized controlled trials exploring the clinical benefits of dexmedetomidine versus propofol for sedation in adult intensive care patients. The primary outcomes of this study were length of ICU stay, duration of mechanical ventilation, and risk of ICU mortality. Secondary outcomes included risk of delirium, hypotension, bradycardia and hypertension. RESULTS: Ten randomized controlled trials, involving 1202 patients, were included. Dexmedetomidine significantly reduced the length of ICU stay by <1 d (five studies, 655 patients; mean difference, -0.81 d; 95% confidence interval [CI], -1.48 to -0.15) and the incidence of delirium (three studies, 658 patients; relative risk [RR], 0.40; 95% CI, 0.22-0.74) in comparison with propofol, whereas there was no difference in the duration of mechanical ventilation (five studies, 895 patients; mean difference, 0.53 h; 95% CI -2.66 to 3.72) or ICU mortality (five studies, 267 patients; RR, 0.83; 95% CI, 0.32-2.12) between these two drugs. Dexmedetomidine was associated with an increased risk of hypertension (three studies, 846 patients; RR, 1.56; 95% CI, 1.11-2.20) compared with propofol. Other adverse event rates were similar between dexmedetomidine and propofol groups. CONCLUSIONS: For ICU patient sedation, dexmedetomidine may offer advantages over propofol in terms of decrease in the length of ICU stay and the risk of delirium. However, transient hypertension may occur when dexmedetomidine is administered with a loading dose or at high infusion rates.