Augmented intracellular glutathione inhibits fas-triggered apoptosis of activated human neutrophils

Q1Q1Agonist signals delivered through cell surface Fas induce apoptosis. However, the apoptotic program can be modulated by signals from the environment, and in particular, by signals delivered through adhesion molecules. Because neutrophil functional activity in inflammation is contingent on cell survival, and because circulating neutrophils normally die rapidly through a constitutively expressed apoptotic program, we evaluated Fas-mediated apoptosis in resting and inflammatory human neutrophils. We show that normal neutrophils respond to Fas engagement with accelerated rates of apoptosis, but cross-linking of β2 integrins or priming with bacterial lipopolysaccharide (LPS) prevents this increase. Adhesion molecule cross-linking results in increased intracellular glutathione (GSH). Augmentation of intracellular GSH with exogenous GSH or N-acetylcysteine is sufficient to reduce the Fas-triggered increase in apoptotic rates. Prevention of the activation induced GSH increase by buthionine sulfoximine, a cell permeable inhibitor of GSH biosynthesis, restored Fas responsiveness in activated neutrophils, an effect that could be blocked with exogenous GSH. Taken together, these data show that Fas-induced signaling for neutrophil apoptosis is blocked in a redox sensitive manner by costimulatory signals delivered through β2 integrins or activation by LPS, and provide a biologic explanation for sustained neutrophil survival in the inflammatory environment.Revista Nacional - Indexad

Hemorrhagic shock primes for increased expression of cytokine-induced neutrophil chemoattractant in the lung: role in pulmonary inflammation following lipopolysaccharide

Q2Q1440-447Recent studies have suggested that hemorrhagic shock followed by resuscitation renders patients more susceptible to lung injury by priming for an exaggerated response to a second stimulus, the so-called "two-hit" hypothesis. We investigated the role of C-X-C chemokines in mediating the augmented lung inflammation in response to LPS following resuscitated shock. In a rodent model, animals exposed to antecedent shock exhibited enhanced lung neutrophil sequestration and transpulmonary albumin flux in response to intratracheal LPS. This effect correlated with an exaggerated expression of cytokine-induced neutrophil chemoattractant (CINC) protein and mRNA, but not macrophage-inflammatory protein 2. Strategies designed to inhibit CINC, both anti-CINC Ab and supplementation with the antioxidant N-acetyl-cysteine, prevented the enhanced neutrophil sequestration, suggesting that CINC played a central role in the enhanced leukocyte accumulation following shock plus LPS treatment. Shock alone increased lung nuclear factor-kappaB expression and augmented the response to LPS. Prevention of this effect by N-acetylcysteine supplementation of the resuscitation fluid implicates a role for oxidant stress in the priming for lung inflammation following shock. Finally, alveolar macrophages recovered from shock-resuscitated animals released more CINC protein in vitro in response to LPS than macrophages from sham animals. Considered together, these findings show that augmented release of CINC, in part from primed alveolar macrophages, contributes significantly to the enhanced lung leukosequestration and transpulmonary albumin flux in response to LPS following resuscitated shock

Profibrotic epithelial phenotype:a central role for MRTF and TAZ

Abstract Epithelial injury is a key initiator of fibrosis but - in contrast to the previous paradigm - the epithelium in situ does not undergo wide-spread epithelial-mesenchymal/myofibroblast transition (EMT/EMyT). Instead, it assumes a Profibrotic Epithelial Phenotype (PEP) characterized by fibrogenic cytokine production. The transcriptional mechanisms underlying PEP are undefined. As we have shown that two RhoA/cytoskeleton-regulated transcriptional coactivators, Myocardin-related transcription factor (MRTF) and TAZ, are indispensable for EMyT, we asked if they might mediate PEP as well. Here we show that mechanical stress (cyclic stretch) increased the expression of transforming growth factor-β1 (TGFβ1), connective tissue growth factor (CTGF), platelet-derived growth factor and Indian Hedgehog mRNA in LLC-PK1 tubular cells. These responses were mitigated by siRNA-mediated silencing or pharmacological inhibition of MRTF (CCG-1423) or TAZ (verteporfin). RhoA inhibition exerted similar effects. Unilateral ureteral obstruction, a murine model of mechanically-triggered kidney fibrosis, induced tubular RhoA activation along with overexpression/nuclear accumulation of MRTF and TAZ, and increased transcription of the above-mentioned cytokines. Laser capture microdissection revealed TAZ, TGFβ1 and CTGF induction specifically in the tubular epithelium. CCG-1423 suppressed total renal and tubular expression of these proteins. Thus, MRTF regulates epithelial TAZ expression, and both MRTF and TAZ are critical mediators of PEP-related epithelial cytokine production

Anatomical, physiological, and logistical indications for the open abdomen: a proposal for a new classification system

Abstract Background A systematic approach to the appropriate use of the open abdomen strategy has not been described. We propose three fundamental reasons for the use of this strategy, anatomical, physiological and logistical. Anatomical reasons pertain to the inability to bring the fascial edges together including soft tissue defects. Physiological reasons relate to features of systemic dysfunction. Logistical reasons involve any anticipated abdominal re-intervention while preserving fascia. These categories occur either as a single reason or in any combination. Methods A single-center prospective observational study of patients with open abdomens in trauma and acute abdomen. Surgeons were asked to select from the three reasons (single or any combination of) their motivation for using the open abdomen upon completion of the initial operation. Patients were compared using the non-parametric Wilcoxon two-sample test or Kruskal-Wallis test. Chi-square or Fisher’s exact test was used for categorical variables; Statistical significance set at P-value ≤ 0.05. Results Forty-five consecutive patients with open abdomens were evaluated (Jan. 1- Dec. 31, 2012). Mean age was 38.8 years, 32 were male, 39 (86.7 %) sustained trauma. The most common single reason for the open abdomen was physiological (24.4 %), 33 patients had multiple reasons, the most common combination being anatomical and physiological (22.2 %). A physiological reason was linked to: lower pH, higher lactate, and lower systolic blood pressure on admission (p < 0.05). A logistical reason was associated with earlier primary fascial closure, intra-operative packing, and bowel left in discontinuity. Logistic regression and adjusted odds ratio of primary fascial closure was: physiological (0.08, 95 % CI, 0.01–0.92, p = 0.043); logistical (6.03, 95 % CI, 1.13–32.29, p = 0.036); and anatomical (0.83, 95 % CI, 0.16–4.18, p = 0.816). Conclusion We defined three basic indications for the use of the open abdomen, anatomical physiological and logistical. These indications establish a practical and comprehensive terminology that could help to promote appropriate use of the open abdomen