Role of p38 and JNK in liver ischemia and reperfusion.

BACKGROUND/PURPOSE: The signal transduction of mitogen-activated protein kinases (MAPKs) has appeared to be an important mediator of ischemic-related events. Because of this, we analyzed the participation of p38 and JNK in liver ischemia and reperfusion, as two individual members of the MAPK family of proteins. METHODS: All papers referred to in PubMed for the past 15 years were analyzed to determine how and when these MAPKs were considered to be an intricate part of the ischemic event. References were cross-studied to ascertain whether other papers could be found in the literature. RESULTS: The role of p38 and JNK in liver ischemia was confirmed in the literature. The activation of these mediators was associated with the induction of apoptosis and necrosis. Inhibitors of p38 and JNK reduced the liver ischemia and reperfusion damage, probably through the mechanisms mentioned before. CONCLUSIONS: The development of effective inhibitors of p38 and JNK protein mediators is important for minimizing the harmful effects associated with liver ischemia and reperfusion.

Inflammatory mediators of liver ischemia-reperfusion injury.

Liver ischemia and reperfusion--which cause liver damage that is significant in a variety of diseases, injuries, and procedures (including but not limited to trauma and transplant)--have been the focus of many investigations in recent years. Although the mechanisms of ischemia-reperfusion injury are numerous and complex, many advances in treatment have been made. The following review considers recent advances in the understanding of hepatic ischemia-reperfusion injury and focuses on inflammatory mediators of significance. To provide a unique analysis and evaluation, we emphasized the most recent pertinent investigations of the last decade. Specific topics addressed include reactive oxygen species, nitric oxide, toll-like receptors, ischemic preconditioning, T cells, heme oxygenase-1, heat shock proteins, erythropoietin, selectins, protein kinases, matrix metalloproteinases, and cytokines.

Resuscitation from hemorrhagic shock comparing standard hemoglobin-based oxygen carrier (HBOC)-201 versus 7.5% hypertonic HBOC-201.

BACKGROUND: Hemoglobin-based oxygen carrier (HBOC) resuscitation has been associated with increased systemic and pulmonary vascular resistances (SVR, PVR), which may result in reduced blood flow and severe pulmonary hypertension. The physiologic and immunologic properties of 7.5% hypertonic saline solution (HTS), such as reduction of SVR and PVR, as well as inhibition of neutrophil and endothelial activation may be beneficial in reducing some of these undesirable effects of HBOCs. The aim of this study was to evaluate the hemodynamic effects of the HBOC and HBOC-201 suspended in 7.5% hypertonic saline solution (HT-HBOC) when compared with standard HBOC resuscitation. METHODS: Thirty-two domestic crossbred pigs (50-60 kg) were hemorrhaged to a mean arterial pressure (MAP) of 35 mm Hg +/- 5 mm Hg for 45 minutes and resuscitated to a baseline mean arterial pressure using the following groups: (1) sham, no hemorrhage; (2) shed blood + lactated Ringer's solution; (3) standard HBOC-201; (4) hypertonic saline 7.5%; (5) hypertonic 7.5% HBOC-201. After resuscitation, observation was continued for 4 hours. Hemodynamic variables, oxygen consumption, and arterial blood gases were monitored continuously. Data were analyzed using analysis of variance. RESULTS: SVR (p = 0.001), PVR (p = 0.001), and MPAP (p = 0.01) were significantly reduced in the HT-HBOC group compared with the standard HBOC group. CONCLUSION: In this model of hemorrhagic shock, hypertonic HBOC-201- resuscitated pigs had significantly reduced SVR and PVR, as well as mean pulmonary artery pressure (MPAP) and increased cardiac output. HT-HBOC may be beneficial in reducing the undesirable effects of standard HBOC-201. The mechanisms of these beneficial effects need to be investigated.

Serum Levels of Neurofilament-H are Elevated in Patients Suffering From Severe Burns.

In previous studies, after injury, burn patients experienced an increase in neuro-inflammation, edema, and neuronal cell death. As demonstrated in other brain injury models, fluid-based biomarkers such as phosphorylated neurofilament-H (pNFL-H) have been shown to correlate with injury severity. In this study the authors hypothesized that burn-injured patients have an increase in pNFL-H in the blood during the acute and chronic time-points after injury. In this prospective clinical study, blood (8 cc) was collected from burn patients (n = 36; TBSA 10-60%) at Parkland hospital, Dallas, Texas, on days 1, 7, and 14 after injury. The serum levels of pNFL-H were measured using the enzyme-linked immunoassay. Compared to noninjured controls, the burn patients exhibited a significant increase in the serum levels of pNFL-H on days 7 (P < .0001) and 14 (P < .0001) after burn injury. No significant increase was observed on day 1 (P < .07) after injury. A positive correlation between TBSA and pNFL-H levels was observed for day 14 (r = .55; P < .03). Additionally, using the receiver operating characteristic analysis, the authors determined the area under the curve was 98% for both day 7 and 14. In conclusion, this study describes the serum profile of pNFL-H in patients suffering from severe burns during the acute (day 1) and chronic (days 7 and 14) time-points. These results suggest that detection of pNFL-H may be useful in determining which individuals suffer from nerve cell degeneration after burn.

Interleukin-6 promoter haplotypes and interleukin-6 cytokine responses.

Genetic variations contribute to differences in the inflammatory response and are markers for disease risk and outcomes. We studied three single-nucleotide polymorphisms (-597 G-->A, -572 G-->C, and -174 G-->C) in the IL-6 promoter to determine associations with ex vivo LPS-stimulated IL-6 production by leukocytes. We also measured nuclear protein binding to synthetic oligonucleotides representing the -174 polymorphic region, located in proximity to important transcription factor motifs. We determined genotypes at three sites in the IL-6 promoter by pyrosequencing of genomic DNA obtained from 49 healthy control subjects. To determine molecular haplotypes, cloned DNA fragments from heterozygous subjects were sequenced. IL-6 release by whole blood leukocytes was measured after 24 h of ex vivo LPS stimulation. We compared IL-6 concentrations between haplotypes using Kruskall-Wallis and adjusted for covariates by analysis of covariance. Electromobility gel shift assay was carried out by the incubation of nuclear proteins from cultured human mononuclear cells with oligonucleotides representing the alternate -174 alleles. The amount of nuclear protein binding was quantified by densitometry, which was compared using analysis of variance. Genotype and sequence analysis of genomic and cloned DNA characterized three haplotypes. Ex vivo IL-6 production was greatest in individuals who were homozygous for the haplotype containing guanine at -597 and -174. IL-6 production was least for individuals homozygous for the haplotype containing adenine at -597 and cytosine at -174. Nuclear protein bound more avidly to guanine-containing oligonucleotides representing the -174 position than to oligonucleotides containing cytosine at that position. The IL-6 promoter haplotype influences ex vivo IL-6 response to endotoxin. This effect may be due to a functional effect of the -174 G-->C polymorphism.

Hypertonic HBOC-201 decreases neutrophil activation after hemorrhagic shock.

OBJECTIVE: To evaluate neutrophil activation after exposure to standard HBC-201 (suspended in lactate Ringer's solution) versus HBOC-201 suspended in hypertonic 7.5% saline solution. METHODS: We use plasma and tissue obtained from pigs subjected to controlled hemorrhagic shock and an ex vivo model of stimulated human whole blood. The pigs were resuscitated with the following (n = 8 per group) standard HBOC-201, or hypertonic HBOC-201. We used HTS 7.5%, Ringer's lactate as control resuscitation. Human blood was stimulated with same fluids. We measured the following neutrophil markers; IL-8, H2O2 in pig plasma, MPO in pig tissue, and H2O2, IL-8, and CD11b/CD18 in human whole blood. RESULTS: H2O2 and IL-8 as well as tissue MPO were significantly decreased in pigs resuscitated with HT-HBOC-201 and HT 7.5%. Ex vivo experiments blood diluted with HTS and HT-HBOC-201 revealed lower expression of CD11b/CD18, H2O2, and IL-8. Blood diluted with HBOC-201 had a higher CD11b/CD18 expression than blood diluted with LR solution. CONCLUSION: Our in vivo and ex vivo experiments indicate that HBOC-201 suspended in hypertonic 7.5% saline solution is associated with significantly less neutrophil activation when compared to standard HBOC-201 suspended in lactate Ringer's solution.

Examination with next-generation sequencing technology of the bacterial microbiota in bronchoalveolar lavage samples after traumatic injury.

BACKGROUND: We examined the microbiota of bronchoalveolar lavage (BAL) samples with next-generation sequencing (NGS) technology to determine whether its results correlate with those of standard culture methods or affect patient outcome or both. METHODS: We collected BAL samples in the surgical intensive care unit (SICU) as part of the standard of care for intubated individuals who had a Clinical Pulmonary Infection Score (CPIS)≥6 points. A portion of the BAL fluid was sequenced for the 16S region of ribosomal deoxyribonucleic acid (rDNA) with the Roche 454 FLX Titanium sequencer. Sequences were analyzed through a data-analysis pipeline to identify the appropriate taxonomic designation (∼species) of each 16s sequence. The bacterial microbiota of each BAL sample was compared with the bacteria identified in the sample through standard culture methods. Correlations between the taxonomic diversity of the microbiota and clinical outcome were examined through linear regression and Pearson correlation. RESULTS: Bronchoalveolar lavage samples from 12 individuals in the SICU who had a CPIS≥6 points were examined through 454 pyrosequencing. The number of phylotypes (∼species) in the samples ranged from 15 to 129. The number of phyla in the BAL samples ranged from 3 to 14. There was little correlation between the bacteria identified by NGS and those identified with standard culture methods. The same predominant bacterial strain was identified by both culture and sequencing in only a single sample. The correlation between patient days on a ventilator and the number of species in BAL samples was significant (r=0.7435, p=0.0056; r2=0.5528). CONCLUSIONS: Increasing diversity of the bacterial microbiota in BAL samples correlates with the duration of mechanical ventilation. Bacteria identified through standard culture methods were not well correlated with the findings of NGS.

A TREM-1 Polymorphism A/T within the Exon 2 Is Associated with Pneumonia in Burn-Injured Patients.

Background. The triggering receptor expressed in myeloid cells (TREM-1) is a key mediator in the activation of the local inflammatory response during lung infections. We aimed to evaluate the effect of a functionally relevant TREM-1 single nucleotide polymorphism within the exon 2 (A→T) on the development of pneumonia in burn patients. Objective. To determine whether a single nucleotide polymorphism (SNP) within the exon 2 (A→T) in the TREM-1 gene is associated with ventilator-associated pneumonia (VAP) in burn-injured patients. Methods. 540 patients with ≥10% total body surface area (TBSA) burn injuries or inhalation injury were prospectively enrolled. The influence of a polymorphism (A→T) in exon 2 of the TREM-1 gene was evaluated for association with increased risk of pneumonia by logistic regression analysis. Measurements and Main Results. 209 patients met criteria for VAP. Multivariate regression analysis showed that, after adjustment for potential confounders, we found that carriage of the TREM-1 T allele is associated with more than a 3-fold increased risk of VAP (OR 6.3, 95% CI 4-9). Conclusions. A TREM-1 single nucleotide polymorphism within the exon 2 (A→T) is associated with the development of pneumonia in burn patients.

Soluble triggering receptor expressed on myeloid cells-1 is an early marker of infection in the surgical intensive care unit.

BACKGROUND: To determine the value of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in early differentiation of systemic inflammatory response syndrome (SIRS) from infection in patients in a surgical intensive care unit (ICU). METHODS: Patients were enrolled if there was clinical suspicion of infection and they fulfilled at least two criteria of SIRS at the time of admission to the ICU. The patients were classified as having SIRS (no infection; n = 37) or infection (n = 56) on the basis of the decision of the treating physician and bacteriological evidence of infection. The plasma concentrations of sTREM-1 in the two groups were compared. RESULTS: Patients with infection had significantly higher sTREM-1 concentrations than patients with SIRS: Median 398 pg/mL (interquartile range [IQR] 302, 552) vs. 78 pg/mL (IQR 28, 150), respectively (p < 0.0001). At a cut-off of 230 pg/mL, sTREM-1 correctly identified patients suffering from infection with 96% sensitivity and 91% specificity. CONCLUSIONS: In the present study, sTREM-1 was an accurate tool for differentiating SIRS from infection in patients in the surgical ICU.

Regional and systemic cytokine responses to acute inflammation of the vermiform appendix.

OBJECTIVE: To measure local (peritoneal fluid) and systemic (plasma) cytokine profiles in patients with infection-inflammation of the vermiform appendix, a relatively mild, localized inflammatory process. SUMMARY BACKGROUND DATA: The systemic host response to invading microorganisms, often termed the systemic inflammatory response syndrome (SIRS), includes changes in heart rate, respiratory rate, body temperature, and circulating white blood cell numbers. Although these changes can be induced experimentally by administering proinflammatory cytokines, the mediators that appear in the bloodstream during early, localized infection in humans have not been defined. METHODS: The authors studied 56 patients with pathologically proven appendicitis. Blood was obtained before the induction of anesthesia, when 82% of the patients met the criteria for SIRS. Peritoneal fluid (PF) was obtained by intraoperative lavage. Cytokines were measured by immunoassay. To assess the net impact of the mediators within plasma, the authors studied the ability of patient plasma to augment or suppress bacterial lipopolysaccharide (LPS) stimulation of monocytes in vitro. RESULTS: Of the proinflammatory cytokines, tumor necrosis factor-alpha was present in PF but not in plasma, interleukin (IL)-1beta and interferon-gamma were found in low concentrations in both PF and plasma, and IL-12 (p70) was detectable in plasma but not PF. In contrast, IL-6 and IL-1 receptor antagonist (IL-1ra) were the most abundant cytokines in the PF and plasma, and the concentrations of IL-4 and IL-10 were also elevated in both compartments. Patients with more severe appendicitis had higher plasma levels of IL-6 and IL-10 and lower plasma levels of IL-12 and interferon-gamma than did those with uncomplicated disease. Patient plasma inhibited LPS-induced stimulation of a monocyte cell line, and this inhibition was accentuated by complicated disease. CONCLUSIONS: As judged from the pattern of soluble cytokines in plasma and the effect of the plasma on monocyte activation by LPS, mild, localized infection can induce a systemic response that is predominantly anti-inflammatory.

Innate immunity genes influence the severity of acute appendicitis.

OBJECTIVE: Using acute appendicitis as a model, we tested the hypothesis that polymorphisms in genes involved in host defense can be associated with the severity of local infection-inflammation in humans. SUMMARY BACKGROUND DATA: Innate immunity is the body's front-line system for antimicrobial host defense. Local inflammation is a major innate immune mechanism for containing and destroying microbes, but it may also contribute to tissue injury. METHODS: We studied 134 patients with acute appendicitis treated at an urban hospital. We looked for associations between the severity of appendicitis (uncomplicated vs. perforated or gangrenous), plasma and peritoneal cytokine concentrations, and single nucleotide polymorphisms in genes involved in recognizing bacterial molecules [CD14 (-159 C-->T); TLR4 (896 A-->G)] and in mounting an inflammatory response [IL-6 (-174 G-->C), TNF-alpha (-308 G-->A), IL-1beta (-31 C -->T)]. RESULTS: Ninety-one patients (68%) had uncomplicated appendicitis and 43 (32%) had complicated disease. The SNPs in the CD14, TLR4, IL-1beta, and TNF-alpha genes were not associated with the severity of appendicitis. A strong association was found between C-allele carriage at -174 in the IL-6 gene and decreased risk of complicated disease (adjusted odds ratio = 0.24, 95% CI = 0.07-0.76). Lower plasma and peritoneal fluid IL-6 concentrations in the IL-6 -174 C-carriers than in the GG homozygotes suggest that this polymorphism contributes to decreased IL-6 production in vivo. CONCLUSIONS: Polymorphism in the IL-6 gene was associated with the severity of appendicitis, even after adjustment for duration of symptoms. The risk for developing appendiceal perforation or gangrene may be determined, in part, by variation in the IL-6 gene.