Background Mortality in sepsis is most often attributed to the development of multiple organ failure. In sepsis, inflammation-mediated endothelial activation, defined as a proinflammatory and procoagulant state of the endothelial cells, has been associated with severity of disease. Thus, the objective of this study was to test the hypothesis that AMPK activation limits inflammation and endothelium activation to protect against organ injury in sepsis. 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR), which is an AMP analogue, has been used to upregulate activity of AMPK. Compound C is a cell-permeable pyrrazolopyrimidine compound that inhibits AMPK activity. Methods Wild-type mice underwent CLP or Sham surgery. Mice were randomized to vehicle, AICAR, or Compound C. Mouse kidney endothelial cells were used for in vitro experiments. Renal and liver function, were determined by serum Cystatin C, BUN, creatinine, and ALT. Serum cytokines were measured by ELISA. Microvascular injury was determined using Evan’s blue dye and electron microscopy. Immunohistochemistry was used to measure protein levels of p-AMPK, LC3, and ICAM. LC3 levels were used as a measure of autophagosome formation. Results AICAR decreased liver, and kidney injury induced by CLP and minimized cytokine elevation, in vivo and in vitro. CLP increased renal and hepatic phosphorylation of AMPK and autophagic signaling as determined by LC3. Inhibition of AMPK with Compound C prevented CLP-induced autophagy and exacerbated tissue injury. Additionally, CLP led to endothelial injury as determined by electron microscopy and Evan’s blue dye extravasation, and AICAR limited this injury. Furthermore, AICAR limited CLP and LPS induced upregulation of ICAM in vivo and in vitro, and decreased LPS induced neutrophil adhesion in vitro. Conclusion In this model, activation of AMPK was protective and AICAR minimized organ injury by decreasing inflammatory cytokines and endothelial activation. These data suggest that AMPK signaling influences sepsis or LPS induced endothelial activation and organ injury.

Acetaminophen (APAP) toxicity is the most common cause of acute liver failure in industrialized countries. Understanding the mechanisms of APAP‐induced liver injury as well as other forms of sterile liver injury is critical to improve the care of patients. Recent studies demonstrate that danger signaling and inflammasome activation play a role in APAP‐induced injury. The aim of these investigations was to test the hypothesis that benzyl alcohol (BA) is a therapeutic agent that protects against APAP‐induced liver injury by modulation of danger signaling. APAP‐induced liver injury was dependent, in part, on Toll‐like receptor (TLR)9 and receptor for advanced glycation endproducts (RAGE) signaling. BA limited liver injury over a dose range of 135‐540 μg/g body weight or when delivered as a pre‐, concurrent, or post‐APAP therapeutic. Furthermore, BA abrogated APAP‐induced cytokines and chemokines as well as high‐mobility group box 1 release. Moreover, BA prevented APAP‐induced inflammasome signaling as determined by interleukin (IL)‐1β, IL‐18, and caspase‐1 cleavage in liver tissues. Interestingly, the protective effects of BA on limiting liver injury and inflammasome activation were dependent on TLR4 signaling, but not TLR2 or CD14. Cell‐type–specific knockouts of TLR4 were utilized to further determine the protective mechanisms of BA. These studies found that TLR4 expression specifically in myeloid cells (LyzCre‐tlr4−/−) were necessary for the protective effects of BA. Conclusion: BA protects against APAP‐induced acute liver injury and reduced inflammasome activation in a TLR4‐dependent manner. BA may prove to be a useful adjunct in the treatment of APAP and other forms of sterile liver injury. (Hepatology 2014;60:990–1002)

Evidence suggests that light and circadian rhythms profoundly influence the physiologic capacity with which an organism responds to stress. However, the ramifications of light spectrum on the course of critical illness remain to be determined. Here, we show that acute exposure to bright blue spectrum light reduces organ injury by comparison with bright red spectrum or ambient white fluorescent light in two murine models of sterile insult: warm liver ischemia/reperfusion (I/R) and unilateral renal I/R. Exposure to bright blue light before I/R reduced hepatocellular injury and necrosis and reduced acute kidney injury and necrosis. In both models, blue light reduced neutrophil influx, as evidenced by reduced myeloperoxidase (MPO) within each organ, and reduced the release of high-mobility group box 1 (HMGB1), a neutrophil chemotactant and key mediator in the pathogenesis of I/R injury. The protective mechanism appeared to involve an optic pathway and was mediated, in part, by a sympathetic (β3 adrenergic) pathway that functioned independent of significant alterations in melatonin or corticosterone concentrations to regulate neutrophil recruitment. These data suggest that modifying the spectrum of light may offer therapeutic utility in sterile forms of cellular injury.

The diagnosis, workup and management of blunt renal injury have evolved greatly over the past decades. Evaluation and management of blunt renal injury echoes the increasing success of nonoperative management in other blunt abdominal solid organ injury, such as liver and spleen. Decision-making difficulties still remain regarding the optimal imaging, grading and degree of interventional or operative exploration used. Increasingly, initial nonoperative management has gained acceptance and appears to be applicable even high-grade injuries. Emerging techniques in highly sensitive imaging as well as interventional angiography have allowed safe nonoperative management in the appropriate patient. This review will focus on the contemporary workup and management of blunt renal injury while focusing on some of the emerging literatures in regard to refined imaging and grading of injuries as well as techniques to increase the success of nonoperative management.

Traumatic injury is a significant cause of morbidity and mortality worldwide. Microcirculatory activation and injury from hemorrhage contributes to organ injury. Many adaptive responses occur within the microcirculatory beds to limit injury including up regulation of heme oxygenase (HO) enzymes, the rate limiting enzymes in the breakdown of heme to carbon monoxide (CO), iron, and biliverdin. Here we tested the hypothesis that CO abrogates trauma induced injury and inflammation protecting the microcirculatory beds. Methods. C57Bl/6 mice underwent sham operation or hemorrhagic shock to a mean arterial pressure of 25mmHg for 120 minutes. Mice were resuscitated with Lactated Ringer’s at 2X the volume of maximal shed blood. Mice were randomized to receive CO-releasing molecule (CO-RM) or inactive CO-RM at resuscitation. A cohort of mice was pretreated with tin protoporphyrin-IX (SnPP) to inhibit endogenous CO generation by heme oxygenases (HO). Primary mouse liver sinusoidal endothelial cells were cultured for in vitro experiments. Results. CO-RM protected against hemorrhagic shock/resuscitation (HS/R) organ injury and systemic inflammation and reduced hepatic sinusoidal endothelial injury. Inhibition of HO activity with SnPP exacerbated liver hepatic sinusoidal injury. HS/R in vivo or cytokine stimulation in vitro resulted in increased endothelial expression of adhesion molecules that was associated with decreased leukocyte adhesion in vivo and in vitro. Conclusions. HS/R is associated with endothelial injury. HO enzymes and CO are involved in part in diminishing this injury and may prove useful as a therapeutic adjunct that can be harnessed to protect against endothelial activation and damage.