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Background Organ injury and dysfunction in sepsis accounts for significant morbidity and mortality. Adaptive cellular responses in the setting of sepsis prevent injury and allow for organ recovery. We and others have shown that part of the adaptive response includes regulation of cellular respiration and maintenance of a healthy mitochondrial population. Herein, we hypothesized that endotoxin-induced changes in hepatocyte mitochondrial respiration and homeostasis are regulated by an inducible nitric oxide synthase/nitric oxide (iNOS/NO)-mitochondrial reactive oxygen species (mtROS) signaling axis, involving activation of the NRF2 signaling pathway. Methods Wild-type (C57Bl/6) or iNos−/− male mice were subjected to intraperitoneal lipopolysaccharide (LPS) injections to simulate endotoxemia. Individual mice were randomized to treatment with NO-releasing agent DPTA-NONOate, mtROS scavenger MitoTEMPO, or vehicle controls. Other mice were treated with scramble or Nrf2-specific siRNA via tail vein injection. Primary murine hepatocytes were utilized for in vitro studies with or without LPS stimulation. Oxygen consumption rates were measured to establish mitochondrial respiratory parameters. Western blotting, confocal microscopy with immunocytochemistry, and rtPCR were performed for analysis of iNOS as well as markers of both autophagy and mitochondrial biogenesis. Results LPS treatment inhibited aerobic respiration in vitro in wild-type but not iNos−/− cells. Experimental endotoxemia in vivo or in vitro induced iNOS protein and mtROS production. However, induction of mtROS was dependent on iNOS expression. Furthermore, LPS-induced hepatic autophagy/mitophagy and mitochondrial biogenesis were significantly attenuated in iNos−/− mice or cells with NO or mtROS scavenging. These responses were rescued in iNos−/− mice via delivery of NO both in vivo and in vitro. Conclusions. These data suggest that regulation of mitochondrial quality control following hepatocyte LPS exposure is dependent at least in part on a NO-mtROS signaling network. Further investigation to identify specific agents that modulate this process may facilitate the prevention of organ injury in sepsis.

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.

Background. Organ injury and dysfunction in sepsis accounts for significant morbidity and mortality. Adaptive cellular responses in the setting of sepsis prevent injury and allow for organ recovery. We and others have shown that part of the adaptive response includes regulation of cellular respiration and maintenance of a healthy mitochondrial population. Herein, we hypothesized that endotoxin-induced changes in hepatocyte mitochondrial respiration and homeostasis are regulated by an inducible nitric oxide synthase/nitric oxide (iNOS/NO)-mitochondrial reactive oxygen species (mtROS) signaling axis, involving activation of the NRF2 signaling pathway.Methods. Wild-type (C57Bl/6) or iNos-/-male mice were subjected to intraperitoneal lipopolysaccharide (LPS) injections to simulate endotoxemia. Individual mice were randomized to treatment with NO-releasing agent DPTA-NONOate, mtROS scavenger MitoTEMPO, or vehicle controls. Other mice were treated with scramble orNrf2-specific siRNAviatail vein injection. Primary murine hepatocytes were utilized forin vitrostudies with or without LPS stimulation. Oxygen consumption rates were measured to establish mitochondrial respiratory parameters. Western blotting, confocal microscopy with immunocytochemistry, and rtPCR were performed for analysis of iNOS as well as markers of both autophagy and mitochondrial biogenesis.Results. LPS treatment inhibited aerobic respirationin vitroin wild-type but notiNos-/-cells. Experimental endotoxemiain vivoorin vitroinduced iNOS protein and mtROS production. However, induction of mtROS was dependent on iNOS expression. Furthermore, LPS-induced hepatic autophagy/mitophagy and mitochondrial biogenesis were significantly attenuated iniNos-/-mice or cells with NO or mtROS scavenging. These responses were rescued iniNos-/-miceviadelivery of NO bothin vivoandin vitro. Conclusions. These data suggest that regulation of mitochondrial quality control following hepatocyte LPS exposure is dependent at least in part on a NO-mtROS signaling network. Further investigation to identify specific agents that modulate this process may facilitate the prevention of organ injury in sepsis.

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.

Hypoxia occurs as a part of multiple disease states, including hemorrhagic shock. Adaptive responses occur within the cell to limit the consequences of hypoxia. This includes changes in mitochondrial respiration, stress-induced cell signaling, and gene expression that is regulated by hypoxia inducible factor-1α(HIF-1α). Heme oxygenase-2 (HO-2) has been shown to be involved in oxygen sensing in several cell types. The purpose of these experiments was to test the hypothesis that HO-2 is a critical regulator of mitochondrial oxygen consumption and reactive oxygen species (ROS) production to influence hypoxia-adaptive responses such as HIF-1αprotein levels and JNK signaling.Methods and Results.In vitrostudies were performed in primary mouse hepatocytes. HO-2, but not HO-1, was expressed in mitochondria at baseline. Decreased oxygen consumption and increased mitochondrial ROS production in response to hypoxia were dependent upon HO-2 expression. HO-2 expression regulated HIF-1αand JNK signaling in a mitochondrial ROS-dependent manner. Furthermore, knockdown of HO-2 led to increased organ damage, systemic inflammation, tissue hypoxia, and shock in a murine model of hemorrhage and resuscitation.Conclusion. HO-2 signaling plays a role in hypoxic signaling and hemorrhagic shock. This pathway may be able to be harnessed for therapeutic effects.

Organ failure in sepsis accounts for significant mortality worldwide. Mitochondrial and metabolic responses are central to the overall response of the cell, and thus of the organ and organism. Adaptive responses in metabolism are critical to the recovery at the cellular level. The purpose of these investigations was to test the hypothesis that sepsis is associated with decreased aerobic respiration and significant metabolic changes in the liver.C57BL/6 mice underwent cecal ligation and puncture (CLP) with a 21 gauge needle or an operation without CLP. Mice were euthanized from 0-24 h after the procedure and liver tissue was harvested. Tissue oxygen consumption and mitochondrial complex activity were measured. Global biochemical profiles of 311 metabolites were performed at the 8-h time point (n = 8/group) and analyzed by gas chromatography-mass spectrometry and liquid chromatography tandem mass spectrometry platforms by Metabolon (Durham, North Carolina). The influence of lipopolysaccharide (LPS) on aerobic and anaerobic respiration in primary mouse hepatocytes was also investigated.CLP in vivo or LPS in vitro resulted in a significant decrease in hepatic oxygen consumption. There was a significant decrease in oxidative phosphorylation measured at 12 h. LPS also resulted in a significant increase in anaerobic respiration in hepatocytes. Interestingly, the metabolomic analysis resulted in a metabolic shift in the liver from carbohydrate-based energy to utilization of fatty acids and amino acids. This included an increase in every tricarboxylic acid cycle intermediate and derivative, suggesting an increased flux into the cycle from fatty acid beta-oxidation and anaplerotic contributions from amino acids.Sepsis results in a metabolic response and profile consistent with increased anaerobic respiration, which occurs prior to significant changes in hemodynamics. The metabolic responses of cells and organs may be important adaptive responses to prevent organ failure and death.

Survival from traumatic injury requires a coordinated and controlled inflammatory and immune response. Mitochondrial and metabolic responses to stress have been shown to play a role in these inflammatory and immune responses. We hypothesized that increases in mitochondrial biogenesis via a sirtuin 1 agonist would decrease tissue injury and partially ameliorate the immunosuppression seen following trauma. C57Bl/6 mice were subjected to a multiple trauma model. Mice were pretreated with either 100 mg/kg per day of the sirtuin 1 agonist, Srt1720, via oral gavage for 2 days prior to trauma and extended until the day the animals were killed, or they were pretreated with peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) siRNA via hydrodynamic tail vein injection 48 h prior to trauma. Markers for mitochondrial function and biogenesis were measured in addition to splenocyte proliferative capacity and bacterial clearance. Srt1720 was noted to improve mitochondrial biogenesis, mitochondrial function, and complex IV activity following traumatic injury (P < 0.05), whereas knockdown of PGC1α resulted in exacerbation of mitochondrial dysfunction (P < 0.05). These changes in mitochondrial function were associated with altered severity of hepatic injury with significant reductions in serum alanine aminotransferase levels seen in mice treated with srt1720. Splenocyte proliferative capacity and intraperitoneal bacterial clearance were evaluated as markers for overall immune function following trauma-hemorrhage. Treatment with Srt1720 minimized the trauma-induced decreases in splenocyte proliferation (P < 0.05), whereas treatment with PGC1α siRNA led to diminished bacterial clearance. The PGC1α signaling pathway is an important regulator of mitochondrial function and biogenesis, which can potentially be harnessed to protect against hepatic injury and minimize the immunosuppression that is seen following trauma-hemorrhage.

Objective The cellular injury that occurs in the setting of hemorrhagic shock and resuscitation (HS/R) affects all tissue types and can drive altered inflammatory responses. Resuscitative adjuncts hold the promise of decreasing such injury. Here we test the hypothesis that sodium nitrite (NaNO 2 ), delivered as a nebulized solution via an inhalational route, protects against injury and inflammation from HS/R. Methods Mice underwent HS/R to a mean arterial pressure (MAP) of 20 or 25 mmHg. Mice were resuscitated with Lactated Ringers after 90–120 min of hypotension. Mice were randomized to receive nebulized NaNO 2 via a flow through chamber (30 mg in 5 mL PBS). Pigs (30–35 kg) were anesthetized and bled to a MAP of 30–40 mmHg for 90 min, randomized to receive NaNO 2 (11 mg in 2.5 mL PBS) nebulized into the ventilator circuit starting 60 min into the hypotensive period, followed by initial resuscitation with Hextend. Pigs had ongoing resuscitation and support for up to four hours. Hemodynamic data were collected continuously. Results NaNO 2 limited organ injury and inflammation in murine hemorrhagic shock. A nitrate/nitrite depleted diet exacerbated organ injury, as well as mortality, and inhaled NaNO 2 significantly reversed this effect. Furthermore, NaNO 2 limited mitochondrial oxidant injury. In porcine HS/R, NaNO 2 had no significant influence on shock induced hemodynamics. NaNO 2 limited hypoxia/reoxia or HS/R-induced mitochondrial injury and promoted mitochondrial fusion. Conclusion NaNO 2 may be a useful adjunct to shock resuscitation based on its limitation of mitochondrial injury.

Aims Currently, there is no effective resuscitative adjunct to fluid and blood products to limit tissue injury for traumatic hemorrhagic shock. The objective of this study was to investigate the role of inhaled carbon monoxide (CO) to limit inflammation and tissue injury, and specifically mitochondrial damage, in experimental models of hemorrhage and resuscitation. Results Inhaled CO (250 ppm for 30 minutes) protected against mortality in severe murine hemorrhagic shock and resuscitation (HS/R) (20% vs. 80%; P

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 adenosine monophosphate-activated protein kinase (AMPK) activation limits inflammation and endothelium activation to protect against organ injury in sepsis. 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), which is an adenosine monophosphate analog, 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 cecal ligation and puncture (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, blood urea nitrogen (BUN), creatinine, and alanine aminotransferase. Serum cytokines were measured by enzyme-linked immunosorbent assay. Microvascular injury was determined using Evans blue dye and electron microscopy. Immunohistochemistry was used to measure protein levels of phospho-AMPK (p-AMPK), microtubule-associated protein 1A/1B-light chain 3 (LC3), and intracellular adhesion molecule. 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 Evans blue dye extravasation, and AICAR limited this injury. Furthermore, AICAR limited CLP and lipopolysaccharide (LPS)-induced upregulation of intracellular adhesion molecule in vivo and in vitro and decreased LPS-induced neutrophil adhesion in vitro. Conclusions 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)

The role of molecular genetics and genomics has risen to great importance in modern medicine. Medicine has seen an exponential growth in methods used to diagnose genetic aberrations leading to better understanding of disease processes. Examples of the advancement have impacted all medical and surgical specialties including improved prenatal screening for rare diseases, pharmacogenetics, and genetic profiling of malignancies. Improved understanding of disease processes at the genetic level has led to improvements in diagnosis, prognosis, and in some cases treatment. Advancements in laboratory methods for RNA and DNA analysis and sequencing have made possible our current understanding of both simple and complex pathology at its fundamental level. Surgeons, physicians, and healthcare professionals must develop an understanding of the methods of RNA and DNA analysis. Reviewed here are the basics and advancements in genetic and genomic analysis that are used in research and clinical medicine.

The design and implementation of massive transfusion protocols with ratio-based transfusion of blood and blood products are important and active areas of investigation. A significant yet controversial body of literature exists to support the use of hemostatic resuscitation in massive transfusion and new data to support the use of adjuncts, such as recombinant factor VIIa and tranexamic acid. We review the developments in massive transfusion research during the past 5 years, including protocol implementation, hemostatic resuscitation, the use of tranexamic acid, and goal-directed therapy for coagulopathy. Furthermore, we provide a level of evidence analysis of the data surrounding the use of component therapy and recombinant factor VIIa in massive transfusion, summary recommendations for the various agents of resuscitation, and new methods of goal-directed therapy.

Increasing evidence suggests that high fresh frozen plasma:packed red blood cell (FFP:PRBC) and platelet:PRBC (PLT:PRBC) transfusion ratios may prevent or reduce the morbidity associated with early coagulopathy which complicates massive transfusion (MT). We sought to characterize changes in resuscitation which have occurred over time in a cohort severely injured patients requiring MT.Data were obtained from a multicenter prospective cohort study evaluating outcomes in blunt injured adults with hemorrhagic shock. MT was defined as requiring ≥10 units PRBCs within 24 hours postinjury. Mean PRBC, FFP, and PLT requirements (per unit; 6 hours, 12 hours, and 24 hours) were determined over time (2004-2009). Sub-MT, those patients just below the threshold for MT, were defined as requiring ≥7 and10 units PRBCs in the initial 24 hours. The percent of resuscitation given at 6 hours relative to 24 hours total (6 of 24%) was determined and compared across "early" (admission until December 2007) and "recent" (after December 2007) periods for each component.Over the study time period (2004-2009) for the MT group (n = 526), initial base deficit and presenting international normalized ratio were unchanged, while Injury Severity Score was significantly higher. The percent of patients who required MT overall significantly decreased over time. No significant differences were found over time for six-hour, 12-hour, or 24-hour FFP:PRBC and PLT:PRBC transfusion ratios in MT patients. Sub-MT patients (n = 344) had significantly higher six-hour FFP:PRBC ratios and significantly higher six-hour,12-hour, and 24-hour PLT:PRBC ratios in the recent time period. The six h/24 h% total for FFP and PLT transfusion was significantly greater in the recent time period. (FFP: 54% vs.70%; p = 0.004 and PLT 46% vs. 61%; p = 0.048).In a severely injured cohort requiring MT, FFP:PRBC and PLT:PRBC ratios have not changed over time, whereas the rate of MT overall has significantly decreased. During the recent time period (after December 2007), significantly higher transfusion ratios and a greater percent of 6-hour/24-hour FFP and PLT were found in the sub-MT group, those patients just below the PRBC transfusion threshold definition of MT. These data suggest early, more aggressive attainment of high transfusions ratios may reduce the requirement for MT and may shift overall blood requirements below those which currently define MT. Further prospective evidence is required to verify these findings.