Tissue coexpression of LBP and CD14 mRNA in a mouse model of sepsis

Protective mechanisms of Leontopodium leontopodioides extracts on lipopolysaccharide-induced acute kidney injury viathe NF-κB/NLRP3 pathway

Sepsis-induced uncontrolled systemic inflammatory response syndrome (SIRS) is a critical cause of multiple organ failure. Acute kidney injury (AKI) is one of the most serious complications associated with an extremely high mortality rate in SIRS, and it lacked simple, safe, and effective treatment strategies. Leontopodium leontopodioides (Willd.) Beauv (LLB) is commonly used in traditional Chinese medicine for the treatment of acute and chronic nephritis. However, it remains unclear whether lipopolysaccharide (LPS) affects LPS-induced AKI. To identify the molecular mechanisms of LLB in LPS-induced HK-2 cells and mice, LLB was prepared by extraction with 70% methanol, while a lipopolysaccharide (LPS)-induced HK-2 cell model and an AKI model were established in this study. Renal histopathology staining was performed to observe the morphology changes. The cell supernatant and kidney tissues were collected for determining the levels of inflammatory factors and protein expression by ELISA, immunofluorescence, and Western blot. The results indicated that LLB significantly reduced the expression of IL-6 and TNF-α in LPS-induced HK-2 cells, as well as the secretion of IL-6, TNF-α, and IL-1β in the supernatant. The same results were observed in LPS-induced AKI serum. Further studies revealed that LLB remarkably improved oxidative stress and apoptosis based on the content of MDA, SOD, and CAT in serum and TUNEL staining results. Notably, LLB significantly reduced the mortality due to LPS infection. Renal histopathology staining results supported these results. Furthermore, immunofluorescence and Western blot results confirmed that LLB significantly reduced the expression of the protein related to the NF-κB signaling pathway and NLRP3, ASC, and Caspase-1 which were significantly increased through LPS stimulation. These findings clearly demonstrated the potential use of LLB in the treatment of AKI and the crucial role of the NF-κB/NLRP3 pathway in the process through which LLB attenuates AKI induced by LPS.

Effect of zinc supplementation on relative expression of immune response genes in neonates with sepsis: A preliminary study

Background & objectives

Zinc alters gene expression mainly by binding to a site on the transcription factor. Genome-wide expression studies have shown early repression of genes related to zinc and immunity in adult patients with sepsis. The present study was conducted to evaluate the role of zinc supplementation on relative expression of immune response genes in neonatal sepsis.

Methods

In the present study, a sample of convenience of 22 neonates each was selected from the zinc supplemented and control groups using random numbers for expression of immune-related genes by zinc supplementation. These neonates with sepsis were earlier randomized into two groups: with and without zinc supplementation in addition to standard antibiotics and supportive care. Relative expression of immune response genes were analyzed for 22 neonates in each group using quantitative real-time PCR for calprotectin (S100A8/A9), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), toll-like receptor-4 (TLR-4), cluster of differentiation 14 (CD14) and lipopolysaccharide-binding protein (LBP) genes.

Results

An increase in serum zinc levels was observed in zinc-supplemented group compared to controls. S100A8 gene showed downregulation by three-fold (P <0.001) and S100A9 gene showed upregulation by two-fold (P <0.05) in zinc group compared to controls. CD14 gene showed upregulation by one-fold in zinc-supplemented group compared to controls (P <0.05). No significant fold changes were observed with respect to TNF-α, IL-6, LBP and TLR-4 genes between the two groups.

Interpretation & conclusions

The results of our preliminary study showed that the zinc supplementation might modulates the relative expression of immune-related genes involved in sepsis pathway among neonates. However, studies with larger sample size are needed to be done to provide a better picture on the outcome by gene expression in neonatal sepsis by zinc supplementation.

Modifications of gut microbiota are associated with the severity of IgA nephropathy in the Chinese population

Immunoglobulin A nephropathy (IgAN) is a common glomerular disease. The pathogenesis of IgAN is associated with dysregulated intestinal mucosal immunity. However, whether gut microbial modifications play a role in IgAN remains unclear. Blood and faecal samples were collected from 52 patients with IgAN and 25 healthy controls (HCs). The gut microbiome was analysed using the 16S ribosomal RNA gene. The levels of galactose-deficient IgA1 (Gd-IgA1), soluble cluster of differentiation 14 (sCD14), lipopolysaccharide binding protein (LBP), intercellular adhesion molecule-1 (ICAM-1), tumour necrosis factor α (TNF-α), interleukin-1, and C-reactive protein were quantified. Substantial differences in the gut microbiota were identified between patients with IgAN and HCs (P < 0.05). Bacteroides and Escherichia-Shigella levels were significantly higher in patients with IgAN than in HCs, while Bifidobacterium and Blautia spp. Levels were lower. Higher proportions of Escherichia-Shigella and lower proportions of Bifidobacterium spp. were observed in patients with IgAN with high urine RBC count (≥10/HP) and proteinuria (≥1 g/24 h) levels. Correlation analysis was used to assess the association between gut microbiota and biomarkers in patients with IgAN. The results showed that Prevotella 7 levels were negatively correlated with Gd-IgA1, LBP, sCD14, ICAM-1, and TNF-α levels, while Bifidobacterium spp. Levels presented a significant inverse relationship with LBP and Gd-IgA1. Additionally, Escherichia-Shigella levels were negatively correlated with Prevotella 7. In patients with IgAN, gut modifications were characterised by an increase in the number of pathogenic bacteria and a reduction in the levels of beneficial bacteria, suggesting that the disturbance of intestinal microflora might be important in the severity of IgAN.

The protective effect of Nigella sativa extract on lung inflammation and oxidative stress induced by lipopolysaccharide in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Oxidative stress during inflammation can increase inflammation and damage tissue. Nigella sativa L. (NS) showed many pharmacological properties including antioxidant and anti-inflammatory activities.

AIM OF THE STUDY

In this study, the preventive effect of NS on lung inflammation and oxidative stress induced by lipopolysaccharide (LPS) in the rats was investigated.

MATERIALS AND METHODS

Male rats were assigned to: Control, LPS (1 mg/kg, i.p.), LPS + NS (100, 200, 400 mg/kg, i.p.), (10 per group). Saline (1 ml/kg) was intra-peritoneal (i.p.) injected instead of LPS in the rats of the control group. LPS dissolved in saline and injected i.p. daily for 14 days. Treatment with NS extracts started two days before LPS administration and treatment continued during LPS administration. White blood cells (WBC), total and differential as well as oxidative stress index in bronchoalveolar fluid (BALF) and serum, TGF-β1, IFN-γ, PGE₂, and IL-4 levels in the BALF and lung histopathology were examined.

RESULTS

LPS administration increased total WBC, eosinophils, neutrophils, basophils, and monocytes counts as well as oxidative stress markers in the BALF and serum as well as TGF-β1, IFN-γ, PGE₂, IL-4 levels in the BALF and pathological changes of the lung tissue. All of these effects were reduced by NS extract treatment dose-dependently.

CONCLUSION

These results suggested the protective effects of NS extract on lung inflammation and oxidative stress as well as its effect on lung pathology induced by LPS dose-dependently.

LPS-Binding Protein Modulates Acute Renal Fibrosis by Inducing Pericyte-to-Myofibroblast Trans-Differentiation through TLR-4 Signaling

During sepsis, the increased synthesis of circulating lipopolysaccharide (LPS)-binding protein (LBP) activates LPS/TLR4 signaling in renal resident cells, leading to acute kidney injury (AKI). Pericytes are the major source of myofibroblasts during chronic kidney disease (CKD), but their involvement in AKI is poorly understood. Here, we investigate the occurrence of pericyte-to-myofibroblast trans-differentiation (PMT) in sepsis-induced AKI. In a swine model of sepsis-induced AKI, PMT was detected within 9 h from LPS injection, as evaluated by the reduction of physiologic PDGFRβ expression and the dysfunctional α-SMA increase in peritubular pericytes. The therapeutic intervention by citrate-based coupled plasma filtration adsorption (CPFA) significantly reduced LBP, TGF-β, and endothelin-1 (ET-1) serum levels, and furthermore preserved PDGFRβ and decreased α-SMA expression in renal biopsies. In vitro, both LPS and septic sera led to PMT with a significant increase in Collagen I synthesis and α-SMA reorganization in contractile fibers by both SMAD2/3-dependent and -independent TGF-β signaling. Interestingly, the removal of LBP from septic plasma inhibited PMT. Finally, LPS-stimulated pericytes secreted LBP and TGF-β and underwent PMT also upon TGF-β receptor-blocking, indicating the crucial pro-fibrotic role of TLR4 signaling. Our data demonstrate that the selective removal of LBP may represent a therapeutic option to prevent PMT and the development of acute renal fibrosis in sepsis-induced AKI.

Renal progenitor cells revert LPS-induced endothelial-to-mesenchymal transition by secreting CXCL6, SAA4, and BPIFA2 antiseptic peptides

Endothelial dysfunction is a hallmark of LPS-induced acute kidney injury (AKI). Endothelial cells (ECs) acquired a fibroblast-like phenotype and contributed to myofibroblast generation through the endothelial-to-mesenchymal transition (EndMT) process. Of note, human adult renal stem/progenitor cells (ARPCs) enhance the tubular regenerative mechanism during AKI but little is known about their effects on ECs. Following LPS exposure, ECs proliferated, decreased EC markers CD31 and vascular endothelial cadherin, and up-regulated myofibroblast markers, collagen I, and vimentin. The coculture with ARPCs normalized the EC proliferation rate and abrogated the LPS-induced EndMT. The gene expression analysis showed that most of the genes modulated in LPS-stimulated ARPCs belong to cell activation and defense response pathways. We showed that the ARPC-specific antifibrotic effect is exerted by the secretion of CXCL6, SAA4, and BPIFA2 produced after the anaphylatoxin stimulation. Next, we investigated the molecular signaling that underlies the ARPC protective mechanism and found that renal progenitors diverge from differentiated tubular cells and ECs in myeloid differentiation primary response 88-independent pathway activation. Finally, in a swine model of LPS-induced AKI, we observed that activated ARPCs secreted CXCL6, SAA4, and BPIFA2 as a defense response. These data open new perspectives on the treatment of both sepsis- and endotoxemia-induced AKI, suggesting an underestimated role of ARPCs in preventing endothelial dysfunction and novel strategies to protect the endothelial compartment and promote kidney repair.-Sallustio, F., Stasi, A., Curci, C., Divella, C., Picerno, A., Franzin, R., De Palma, G., Rutigliano, M., Lucarelli, G., Battaglia, M., Staffieri, F., Crovace, A., Pertosa, G. B., Castellano, G., Gallone, A., Gesualdo, L. Renal progenitor cells revert LPS-induced endothelial-to-mesenchymal transition by secreting CXCL6, SAA4, and BPIFA2 antiseptic peptides.

Sepsis Upregulates CD14 Expression in a MyD88-Dependent and Trif-Independent Pathway

An overwhelming immune response, particularly from macrophages, plays a critical role in survival and organ damage in sepsis patients. Toll-like receptors (TLRs) are important receptors to recognize the conserved motifs expressed by invading bacteria. The TLRs except TLR3 signal via a MyD88-dependent pathway. TLR3 uses a TRIF-dependent pathway, while TLR4 uses both MyD88 and TRIF-dependent pathways. Previous studies indicated that CD14 was necessary for TLRs-dependent production of pro-inflammatory cytokines. Blocking CD14 protected against the deleterious systemic inflammatory response associated with sepsis. The aim of this study was to determine the signaling pathway of TLR activation-induced CD14 expression in models of polymicrobial sepsis and in peritoneal macrophages. We found that CD14 expression was upregulated in the lung, liver, and kidney of septic mice induced by cecal ligation puncture. In cultured peritoneal macrophages, specific agonists for all TLRs, except for TLR3, increased CD14 expression. Lipopolysaccharide-induced upregulation of CD14 was abolished in peritoneal macrophages from MyD88 KO mice but increased in TRIF inhibitor, resveratrol pretreated wild-type macrophages. Moreover, MyD88 KO, but not TRIF KO mice, showed a decreased CD14 expression in the tissue of septic mice, which was associated with a strongly attenuated inflammatory response and increased survival rate. These data suggest that a MyD88-dependent and TRIF-independent pathway of TLR is activated in upregulating CD14 expression under septic conditions. This study deciphers a critical cross-talk between TLRs and CD14.

Disruption of female reproductive function by endotoxins

Endotoxemia can be caused by obesity, environmental chemical exposure, abiotic stressors and bacterial infection. Circumstances that deleteriously impact intestinal barrier integrity can induce endotoxemia, and controlled experiments have identified negative impacts of lipopolysaccharide (LPS; an endotoxin mimetic) on folliculogenesis, puberty onset, estrus behavior, ovulation, meiotic competence, luteal function and ovarian steroidogenesis. In addition, neonatal LPS exposures have transgenerational female reproductive impacts, raising concern about early life contacts to this endogenous reproductive toxicant. Aims of this review are to identify physiological stressors causing endotoxemia, to highlight potential mechanism(s) by which LPS compromises female reproduction and identify knowledge gaps regarding how acute and/or metabolic endotoxemia influence(s) female reproduction.

Hyperlipoproteinemic low-density lipoprotein receptor-deficient mice are more susceptible to sepsis than corresponding wild-type mice

High circulating concentrations of lipoproteins have been shown to modify the cytokine response and reduce mortality after endotoxin or live bacterial challenge. Sepsis, however, is more complex than endotoxemia, and it is not clear whether elevated plasma lipoproteins will be protective. Previous studies have shown that the low-density-lipoprotein receptor deficient (LDLR —/— ) mice with increased circulating LDL are protected against the lethal effects of endotoxemia and Gram-negative infection. We evaluated whether the LDLR —/— mice would be protected against the effects of sepsis induced by cecal ligation and puncture (CLP). Mortality was greater in LDLR—/ — mice than in control C57Bl/6J mice. At 120 h after inducing sepsis, 20% of the control mice survived whereas none of the LDLR—/— mice were alive. Prior to inducing sepsis, serum concentrations of amyloid A protein and lipopolysaccharide binding protein (LBP) were significantly elevated in the LDLR —/— mice in comparison to the C57Bl/6J mice. Protein expression of sCD14 was also greater in the serum from the LDLR —/ — mice than the C57Bl/6J mice. The elevated serum concentrations of LBP and CD14 were not associated with increases in the levels of liver CD14 mRNA and LBP mRNA. After inducing sepsis, serum concentration of interleukin (IL)-1β was also significantly higher in LDLR — /— mice than in the control C57Bl/6J mice. These findings indicate that the LDLR — /— mice were more susceptible to the lethal effects of sepsis induced by CLP. The LDLR — /— mice also had higher serum concentrations of baseline, acute phase response proteins, SAA and LBP, and increased production of IL-1β in response to CLP.

Antiseptic effect of vicenin-2 and scolymoside from Cyclopia subternata (honeybush) in response to HMGB1 as a late sepsis mediator in vitro and in vivo

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, which are 2 active compounds from C. subternata that act against high mobility group box 1 (HMGB1)-mediated septic responses in human umbilical vein endothelial cells (HUVECs) and mice. The antiseptic activities of vicenin-2 and scolymoside were determined by measuring permeability, neutrophil adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice. According to the results, vicenin-2 and scolymoside effectively inhibited lipopolysaccharide-induced release of HMGB1, and suppressed HMGB1-mediated septic responses such as hyperpermeability, the adhesion and migration of leukocytes, and the expression of cell adhesion molecules. In addition, vicenin-2 and scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6, and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by HMGB1. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agents for the treatment of various severe vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Super-low dose endotoxin pre-conditioning exacerbates sepsis mortality

Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditioning with super-low or low dose endotoxin lipopolysaccharide (LPS) cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP). This is in contrast to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET) in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks.

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Super-low dose endotoxin pre-conditioning exacerbates, while higher dose endotoxin alleviates sepsis mortality.

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Super-low dose endotoxin reduces, while higher dose endotoxin facilitates neutrophil extracellular trap (NET) formation.

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Super-low dose endotoxin suppresses, while higher dose endotoxin induces ERK activation required for NET formation.

Normal mesenteric lymph ameliorates acute kidney injury following lipopolysaccharide challenge in mice

BACKGROUND

The kidney is one of the prior damaged organs subjected to severe infection and sepsis shock. Our previous studies have shown that the normal mesenteric lymph (NML) obtained from healthy dogs could alleviate multiple organ injuries following endotoxic shock. In the current study, we further investigated the beneficial effect of NML from healthy mice on acute kidney injury (AKI) induced by lipopolysaccharide (LPS) in mice.

METHODS

The mice in LPS and LPS + NML groups received an intraperitoneal injection of LPS (35 mg/kg). One hour later, the treatment of NML was performed and kept for 6 h. Then, the renal function indices, renal morphology, the levels of phosphorylation mitogen-activated protein kinases (MAPKs), markers of sensitization to LPS, as well as pro-inflammatory mediators in renal tissue were observed.

RESULTS

Intraperitoneal injection of LPS induced an increased level of urea in plasma, lipopolysaccharide-binding protein (LBP), cluster of differentiation 14 (CD14), tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6), but no obvious changes in the MAPKs in renal tissue. NML treatment decreased the levels of urea, CD14, TNF-α and IL-6 in mice after LPS injection.

CONCLUSION

The current results indicate that NML alleviates LPS-induced AKI through its attenuation of sensitization to LPS.

Ingested soluble CD14 contributes to the functional pool of circulating sCD14 in mice

Soluble CD14 (sCD14) is a pattern recognition receptor and Toll-like co-receptor observed in human milk (5-26μg/mL) and other bodily fluids such as blood (3μg/mL). The most well defined role of sCD14 is to recognize lipopolysaccharide of Gram-negative bacteria and signal an immune response through Toll-like receptor 4 (TLR4). Previous research has shown ingested sCD14 to transfer from the gastrointestinal tract and into the blood stream in neonatal rats. The contribution of human milk sCD14 to circulating levels in the infant and the functionality of the protein, however, remained unknown. Using CD14(-/-) mouse pups fostered to wild type (WT) mothers expressing sCD14 in their milk, we show herein that ingestion of sCD14 resulted in blood sCD14 levels up 0.16±0.09μg/mL. This represents almost one-third (26.7%) of the circulating sCD14 observed in WT pups fostered to WT mothers (0.60±0.14μg/mL). We also demonstrate that ingested-sCD14 transferred to the blood remains functional in its ability to recognize lipopolysaccharide as demonstrated by a significant increase in immune response (IL-6 and TNF-α) in CD14(-/-) pups fostered to WT mothers in comparison to control animals (P=0.002 and P=0.007, respectively). Using human intestinal cells (Caco-2), we also observed a significant decrease in sCD14 transcytosis when TLR4 was knocked down (P<0.001), suggesting sCD14 transfer involves TLR4. The bioavailability of human milk sCD14 established in this report confirms the importance of human milk proteins for the infant and demonstrates the need to improve infant formulas which are lacking in immune proteins such as sCD14.

The anti-inflammatory effect of the synthetic antimicrobial peptide 19-2.5 in a murine sepsis model: a prospective randomized study

Introduction

Increasing rates of multi-resistant bacteria are a major problem in the treatment of critically ill patients. Furthermore, conventional antibiotics lead to the release of bacterial derived membrane parts initiating pro-inflammatory cascades with potential harm to the patient. Antimicrobial peptides (AMP) may kill bacteria without releasing pro-inflammatory factors. Thus, we compared three newly developed synthetic anti-lipopolysaccharide peptides (SALPs) with a broader range of efficacy to suppress cytokine release in plasma and CD14 mRNA expression in organ tissue in a murine, polymicrobial sepsis model.

Methods

A randomized, experimental trial was conducted in an animal research facility. Male NMRI mice (n = 90; 8- to 12-weeks old) were randomized to the following six groups: (i) sham operation and parenteral vehicle (NaCl 0.9%) administration (sham); (ii) cecal ligation and puncture (CLP) and vehicle infusion (sepsis-control), (iii) CLP and polymyxin B infusion (polyB), or (iv to vi) CLP and infusion of three different synthetic antimicrobial peptides Peptide 19-2.5 (Pep2.5), Peptide 19-4 (Pep4) or Peptide 19-8 (Pep8). All animals underwent arterial and venous catheterization for hemodynamic monitoring 48 hours prior to CLP or sham-operation. Physical appearance and behavior (activity), plasma cytokine levels, and CD14 mRNA expression in heart, lung, liver, spleen and kidney tissue were determined 24 hours after CLP or sham operation.

Results

Only Pep2.5 significantly enhanced the activity after CLP, whereas none of the therapeutic regimens elevated the mean arterial pressure or heart rate. The strongly elevated IL-6, IL-10 and monocyte chemoattractant protein serum levels in septic animals were significantly reduced after Pep2.5 administration (P < 0.001, P < 0.001, and P < 0.001, respectively). Similarly, Pep2.5 significantly reduced the sepsis-induced CD14 mRNA expression in heart (P = 0.003), lung (P = 0.008), and spleen tissue (P = 0.009) but not in kidney and liver.

Conclusions

Structurally variable SALPs exhibit major differences in their anti-inflammatory effect in vivo. Continuous parenteral administration of Pep2.5 is able to reduce sepsis-induced cytokine release and tissue inflammation.

Time course of the inflammatory and oxidative stress response to pulmonary infection in mice

The pathophysiological response to pulmonary infection includes a surge of proinflammatory cytokines and excessive production of nitric oxide (NO), but the time changes are not sufficiently defined. The current study was designed to assess the time course of proinflammatory cytokines and NO production in a murine model of pulmonary infection. The injury was induced by intranasal administration of live Pseudomonas aeruginosa (3.2 × 10(7) colony-forming units) in C57BL/6 wild-type mice. The animals were euthanized at 3, 6, 9, 12, and 15 hours postinjury. Additional mice received sham injury (0 hours; control). Lung tissue and plasma samples were harvested at the respective time points. The injury induced an early increase in interleukin (IL)-1 β protein in lung tissue that persisted during the entire study period with a peak at the 9-hour time point. The increases in TNF-α and IL-6 proteins in lung tissue were less intense, but showed a peak about 9 hours postinjury. The plasma levels of IL-1 β and tumor necrosis factor (TNF)-α protein were not elevated during the experimental period, but only an increase in plasma levels of IL-6 plasma protein was detected. These findings compensate for the limitations of previous experiments with similar infection models and improve the understanding of pathophysiologic alterations in response to pulmonary infection. In addition, the identification of the time changes of the described pathogenetic factors may enhance the timing of innovate therapeutic approaches in future experiments.

Old and new findings on lipopolysaccharide-binding protein: a soluble pattern-recognition molecule

LBP [LPS (lipopolysaccharide)-binding protein] was discovered approximately 25 years ago. Since then, substantial progress has been made towards our understanding of its function in health and disease. Furthermore, the discovery of a large protein family sharing functional and structural attributes has helped in our knowledge. Still, key questions are unresolved, and here an overview on the old and new findings on LBP is given. LBP is an acute-phase protein of the liver, but is also synthesized in other cells of the organism. While LBP is named after the ability to bind to LPS of Gram-negative bacteria, it also can recognize other bacterial compounds, such as lipopeptides. It has been shown that LBP is needed to combat infections; however, the main mechanism of action is still not clear. New findings on natural genetic variations of LBP leading to functional consequences may help in further elucidating the mechanism of LBP and its role in innate immunity and disease.

The value of the lipopolysaccharide-induced acute lung injury model in respiratory medicine

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a syndrome characterized by pulmonary edema and acute inflammation. Lipopolysaccharide (LPS), a major component in Gram-negative bacteria, has been used to induce ALI/ARDS. LPS-induced animal models highlight ways to explore mechanisms of multiple diseases and provide useful information on the discovery of novel biomarkers and drug targets. However, each model has its own merits and drawbacks. The goal of this article is to summarize and evaluate the results of experimental findings in LPS-induced ALI/ARDS, and the possible mechanisms and treatments elucidated. Advantages and disadvantages of such models in pulmonary research and new directions for future investigations are also discussed.

The innate immune response to secondary peritonitis

Secondary peritonitis continues to cause high morbidity and mortality despite improvements in medical and surgical therapy. This review combines data from published literature, focusing on molecular patterns of inflammation in pathophysiology and prognosis during peritonitis. Orchestration of the innate immune response is essential. To clear the microbial infection, activation and attraction of leukocytes are essential and beneficial, just like the expression of inflammatory cytokines. Exaggeration of these inflammatory systems leads to tissue damage and organ failure. Nonsurvivors have increased proinflammation, complement activation, coagulation, and chemotaxis. In these patients, anti-inflammatory systems are decreased in blood and lungs, whereas the abdominal compartment shows decreased neutrophil activation and decreased or stationary chemokine and cytokine levels. A later down-regulation of proinflammatory mediators with concomitant overexpression of anti-inflammatory mediators leads to immunoparalysis and failure to clear residual bacterial load, resulting in the occurrence of superimposed infections. Thus, in patients with adverse outcome, the inflammatory reaction is no longer contained within the abdomen, and the inflammatory response has shifted to other compartments. For the understanding of the host response to secondary peritonitis, it is essential to realize that the defense systems presumably are expressed differently and, in part, autonomously in different compartments.

Lipopolysaccharide-binding protein modulates hepatic damage and the inflammatory response after hemorrhagic shock and resuscitation

Hemorrhagic shock and resuscitation cause endotoxemia and hepatocellular damage. Because lipopolysaccharide-binding protein (LBP) enhances cellular responses to endotoxin, our aim was to determine whether LBP contributes to hemorrhage/resuscitation-induced injury by comparing LBP knockout and wild-type mice. Under pentobarbital anaesthesia, wild-type and LBP-deficient mice were hemorrhaged to 30 mmHg for 3 h and then resuscitated with shed blood plus half the volume of lactated Ringer solution. Serum alanine aminotransferase (ALT) necrosis, neutrophil infiltration, and 4-hydroxynonenal by histology/cytochemistry and stress kinase activation by immunoblot analysis were then determined. ALT in wild-type mice was 2,461 +/- 383 and 1,418 +/- 194 IU/l (means +/- SE), respectively, at 2 and 6 h after resuscitation versus sham ALT of 102 +/- 6 IU/l. In LBP-deficient mice, ALT was blunted at both time points to 1,108 +/- 340 and 619 +/- 171 IU/l (P < 0.05). Liver necrosis after 6 h was also attenuated from 3.5 +/- 0.8% in wild-type mice to 1.3 +/- 0.5% in LBP-deficient mice (P < 0.05). After hemorrhage/resuscitation, neutrophil infiltration increased 71% more in wild-type than LBP knockout mice. Similarly, hepatic 4-hydroxynonenal staining, indicative of lipid peroxidation, decreased from 33.8 +/- 4.5% in wild-type mice to 11.6 +/- 1.9% in knockout mice (P < 0.05). After hemorrhage/resuscitation, activation of MAPKs, JNK and ERK, occurred in wild-type mice, which was largely blocked in LBP-deficient mice. However, endotoxin in portal blood after resuscitation was not significantly different between wild-type and knockout mice. In conclusion, hemorrhagic shock and resuscitation to mice cause severe, LBP-mediated hepatocellular damage. An absence of LBP blunts hepatocellular injury with decreased neutrophil infiltration, oxidative stress, and c-Jun and ERK activation.

Upregulation of TNF-alpha and IL-6 mRNA in mouse liver induced by bacille Calmette-Guerin plus lipopolysaccharide

AIM

To investigate the mechanism of immunological liver injury induced by bacille Calmette-Guerin (BCG) plus lipopolysaccharide (LPS).

METHODS

Mice were injected via the tail vein with 125 mg/kg BCG, and 12 d later, the mice were injected intravenously with different doses of LPS (125, 250, or 375 microg/kg). Serum alanine aminotransferase (ALT) activity and liver pathological changes were examined. The expression of tumor necrosis factor (TNF)- alpha, interleukin (IL)-6, lipopolysaccharide binding protein (LBP) and CD14 mRNA, and NF-kappaB and IkappaB-alpha protein in mouse liver at different time points after BCG and LPS injection were measured using RT-PCR, immunohistochemistry and Western blotting analysis, respectively.

RESULTS

The activity of serum ALT in mice treated with BCG and LPS was significantly increased. Different degrees of liver injury, such as inflammatory cell infiltration, spotty necrosis, piecemeal necrosis, even bridging necrosis, could be seen in liver sections from mice after BCG and LPS administration. Furthermore, the levels of TNF-alpha and IL-6 mRNA in mouse liver were significantly elevated after administration of BCG plus LPS (P<0.05). The levels of LBP and CD14 mRNA in mouse liver were markedly upregulated after treatment with BCG and LPS, and treatment with BCG alone led to an increase in CD14 mRNA in mouse liver. Finally, immunoreactivity for NF-kappaB p65 was predominantly detected in hepatocyte nuclei from mice treated with BCG plus LPS, compared with the normal group. Protein levels of IkappaB-alpha were strikingly decreased by LPS or BCG plus LPS treatment, compared with the normal group or BCG group.

CONCLUSION

TNF-alpha and IL-6 mRNA were partially involved in early immunological liver injury induced by challenge with small doses of LPS after BCG priming. Upregulation of TNF-alpha and IL-6 mRNA might be related to increases in LBP and CD14 mRNA expression and activation of NF-kappaB. Furthermore, BCG priming in immunological liver injury may occur via upregulation of CD14 mRNA expression in mononuclear cell infiltration into the liver.

Lewis and Fischer 344 strain differences in α2-adrenoceptors and tyrosine hydroxylase expression

Lewis and Fischer 344 (F344) rats differ in their pharmacological responses to a variety of drugs such as opioids, which has been partially attributed to differences in the endogenous opioid tone. Since opioid and alpha2-adrenergic mechanisms closely interact in nociception and substance abuse, a comparative study of the endogenous alpha2-adrenergic system in both inbred strains is of interest. Alpha-2 adrenoceptor subtypes and tyrosine hydroxylase, the rate-limiting enzyme of the catecholamine biosynthesis, were studied by Taqman RT-PCR analysis of gene expression in four brain areas of F344 and Lewis rats: hypothalamus, hippocampus, striatum and cortex. No differences were found in the mRNA levels of alpha2A- and alpha2C-adrenoceptors in any of the areas examined, however F344 rats exhibited lower levels of alpha2B-adrenoceptor transcripts in the hippocampus and higher levels in the hypothalamus. Tyrosine hydroxylase gene expression was found to be higher in hippocampus and striatum of F344 rats compared to Lewis, and a consistent 2-fold increase of the protein levels was detected by Western blots only in the case of the hippocampus. These results together with previous studies strongly suggest that the hippocampal noradrenergic activity of Lewis and F344 rats could be involved in their different responses to pain, stress and drug addiction.

[Relaparotomy in secondary peritonitis Planned relaparotomy or relaparotomy on demand?]

Secondary peritonitis is associated with serious morbidity and a persistent high mortality in recent decades, this despite improvement in antibiotic, intensive care and surgical treatment. The available literature regarding the surgical treatment of secondary peritonitis was searched through Pubmed (1966- January 2005) as well as a hand search of references of retrieved articles. Definitions, pathophysiology and classification of secondary peritonitis are discussed, as well as the scientific rationale for the surgical treatment in secondary peritonitis. The historical development and the scientific foundation of present-day relaparotomy strategies in secondary peritonitis are evaluated, with an emphasis on two frequently applied surgical treatment strategies: planned relaparotomy and relaparotomy on demand. Criteria for relaparotomy after the initial laparotomy and potential areas for further research to reduce both morbidity and mortality are discussed. Furthermore, the care of patients with secondary peritonitis is evolving from a surgical entity to a more multidisciplinary challenge uniting surgeons, intensivists, radiologists and microbiologists. Research needs to be expanded into novel fields to further decrease morbidity and mortality.

Ethyl pyruvate decreases sepsis-induced acute renal failure and multiple organ damage in aged mice

BACKGROUND

Sepsis is a common cause of acute renal failure (ARF). The incidence of sepsis increases dramatically after 50 years of age; however, most ARF studies are performed in young mice.

METHODS

We performed two common sepsis models, lipopolysaccharide (LPS) administration and cecal ligation puncture (CLP) in aged mice. We developed a fully treated CLP model in aged mice by treating mice with fluid resuscitation and antibiotics.

RESULTS

LPS induced renal injury in aged but not young mice. However, volume resuscitation starting within 6 hours decreased renal injury. We then used this fluid resuscitation scheme, along with antibiotics, to develop a fully treated CLP model in aged mice. Mice subjected to CLP developed functional and histologic ARF and multiple organ damage. Treatment with ethyl pyruvate, even when started 12 hours after surgery, decreased serum creatinine, tubular damage, and multiple organ injury at 24 hours. Ethyl pyruvate decreased plasma tumor necrosis factor-alpha (TNF-alpha), and kidney mRNA for TNF alpha, tissue factor, and plasminogen activator inhibitor-1 (PAI-1), and increased mRNA for urokinase-like plasminogen activator.

CONCLUSION

CLP in aged mice causes functional and histologic changes consistent with human ARF. A single dose of ethyl pyruvate inhibits renal and multiple organ damage, and is still effective when given 12 hours after surgery.

Rapid detection of subtelomeric deletion/duplication by novel real-time quantitative PCR using SYBR-green dye

Telomeric chromosome rearrangements may cause mental retardation, congenital anomalies, miscarriages, and hematological malignancies. Automated detection of subtle deletions and duplications involving telomeres is essential for high-throughput screening procedures, but impractical when conventional cytogenetic methods are used. Novel real-time PCR quantitative genotyping of subtelomeric amplicons using SYBR-green dye allows high-resolution screening of single copy number gains and losses by their relative quantification against a diploid genome. To assess the applicability of the technique in the screening and diagnosis of subtelomeric imbalances, we describe here a blinded study in which DNA from 20 negative controls and 20 patients with known unbalanced cytogenetic abnormalities involving at least one or more telomeres were analyzed using a novel human subtelomere-specific primer set, producing altogether 86 amplicons, in the SYBR-green I-based real-time quantitative PCR screening approach. Screening of the DNA samples from 20 unrelated controls for copy number polymorphism do not detect any polymorphism in the set of amplicons, but single-copy-number gains and losses were accurately detected by quantitative PCR in all patients, except the copy number alterations of the subtelomeric p-arms of the acrocentric chromosomes in two cases. Furthermore, a detailed mapping of the deletion/translocation breakpoint was demonstrated in two cases by novel real-time PCR "primer-jumping." Because of the simplicity and flexibility of the SYBR-green I-based real-time detection, the primer-set can easily be extended, either to perform further detailed molecular characterization of breakpoints or to include amplicons for the detection and/or analysis of syndromes that are associated with genomic copy number alterations, e.g., deletion/duplication-syndromes and malignant cancers.

Cloning and analyses of a BPI/LBP cDNA of the Atlantic cod (Gadus morhua L.)

Using the differential screening technique, a cDNA related to the mammalian family of lipid transfer/lipopolysaccharide-binding proteins was cloned from the Atlantic cod (Gadus morhua L.). The gene is an ortholog of a recently identified gene of rainbow trout (Oncorhynchus mykiss). Phylogenetic analyses suggest that teleost BPI/LBP are modern descendants of the ancestor of mammalian bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP), and a gene of the urochordate Ciona intestinalis is related to this gene family. Molecular modeling suggests that the structure of cod BPI/LBP is similar to mammalian BPI and LBP, while its highly basic character is similar to BPI. Cod BPI/LBP is constitutively expressed in head-kidney (HK) leukocytes. After intraperitoneal injection of bacterin high levels of cod BPI/LBP mRNA were detected also in peripheral blood cells and spleen, while moderate to low levels of transcript were found in heart, liver, gills, skin, brain, and intestine. We conclude that the patterns of charge and expression of cod BPI/LBP are more similar to mammalian BPI than to mammalian LBP.

A new quantitative PCR multiplex assay for rapid analysis of chromosome 17p11.2-12 duplications and deletions leading to HMSN/HNPP

A 1.4-Mb tandem duplication, including the gene for peripheral myelin protein 22 (PMP22) in chromosome 17p11.2-12 is responsible for 70% of the cases of the demyelinating type 1 of Charcot-Marie-Tooth disease or hereditary motor and sensory neuropathy I (CMT1A/HMSN I). A reciprocal deletion of this CMT1A region causes the hereditary neuropathy with liability to pressure palsies (HNPP). The CMT1A duplication increases the PMP22 gene dosage from two to three, the HNPP deletion reduces the gene dosage from two to one. Currently, routine diagnosis of HMSN/HNPP patients is mainly performed with polymorphic markers in-between the repetitive elements flanking the CMT1A region. These show quantitative and/or qualitative changes in case of a CMT1A duplication and a homozygous allele pattern in case of HNPP deletion. In HNPP patients the deletion is usually confirmed by fluorescence in situ hybridisation (FISH). We now developed a reliable, single tube real-time quantitative PCR assay for rapid determination of PMP22 gene dosage directly. This method involves a multiplex reaction using FAM labelled Taqman-probe with TAMRA quencher derived from PMP22 exon 3 and a VIC labelled probe with non-fluorescent quencher from exon 12 of the albumin gene as internal reference. Copy number of the PMP22 gene was determined by the comparative threshold cycle method (deltadeltaCt). Each sample was run in quadruplicate and analysed at two different threshold levels. The level giving the smallest standard deviation was scored. We evaluated this method through the retrospective analysis of 252 HMSN patients with known genotype and could confirm the previous findings in 99% of cases. Two patients were wrongly diagnosed with microsatellite analysis while quantitative real-time PCR identified the correct genotype, as confirmed by FISH. Thus, this method shows superior sensitivity to microsatellite analysis and has the additional advantage of being a fast and uniform assay for quantitative analysis of both CMT1A and HNPP.

An essential role for lipopolysaccharide-binding protein in pulmonary innate immune responses

Lipopolysaccharide (LPS)-binding protein (LBP) greatly facilitates LPS activation of monocytic cells through the CD14 receptor, triggering activation of innate immune responses. An acute phase protein, LBP is produced predominantly by the liver; however, we and others have shown that LBP is produced extrahepatically in multiple locations, including the lung. The importance of LBP in the lung has remained unclear. LBP may make the host more acutely sensitive to LPS and development of septic complications; alternatively, it may be protective, aiding in detection, opsonization, and killing of bacteria. Our objective was to determine the role LBP plays in local pulmonary immune defenses to bacterial challenge. LBP knockout mice and age-matched C57BL/6 wild-type controls were challenged with direct intratracheal inoculation of Klebsiella pneumoniae. We observed a significant increase in mortality, earlier onset of bacteremia, and greater pulmonary bacterial loads in LBP knockout mice compared with controls. Total lung myeloperoxidase (MPO) activity, neutrophil recruitment to the alveolar space, and levels of KC--a chemokine involved in neutrophil recruitment--in bronchoalveolar lavage (BAL) fluid and lung homogenates were found to be significantly diminished in knockout mice compared with controls. Together, our findings suggest that LBP is essential in local pulmonary innate immune responses against bacteria.

Lipopolysaccharide induced synthesis of CD14 proteins and its gene expression in hepatocytes during endotoxemia

AIM: To observe synthesis of CD14 protein and expression of CD14 mRNA in hepatic tissue and hepatocytes of rats during endotoxemia.

METHODS: The endotoxemia model of Wistar rat was established by injection of a dose of lipopolysaccharide (LPS) (5 mg·kg^-1, Escherichia coli O111:B4) via the tail vein, and then the rats were sacrificed after 3, 6, 12 and 24 h in batches. Hepatocytes were isolated from normal and LPS-injected rats by in situ collagenase perfusion technique and were collected to measure the expression of CD14 mRNA and synthesis of CD14 protein by reverse transcript-polymerase chain reaction (RT-PCR) or Western blot analysis. The binding of fluorescein isothiocyanate (FITC)-CD14 polyclonal antibody to isolated hepatocytes was also assessed by flow cytometric analysis (FCM).

RESULTS: In the rats with endotoxemia, the expressions of CD14 mRNA in hepatic tissue and isolated hepatocytes were stronger at 3, 6, and 12 h than that in control rats (3.48 ± 0.15, 5.89 ± 0.62, 4.33 ± 0.18, vs 1.35 ± 0.14 in hepatic tissue, P < 0.01; 4.12 ± 0.17, 6.24 ± 0.64, 4.35 ± 0.18, vs 1.87 ± 0.15 in hepatocytoes, P < 0.01).The synthesis of CD14 protein in hepatic tissue and isolated hepatocytes increases also obviously in 6 and 12 h when compared to that in control rats (13.27 ± 1.27, 17.32 ± 1.35, 11.42 ± 1.20,vs 7.34 ± 0.72 in hepatic tissue, P < 0.01; 14.68 ± 1.30, 17.95 ± 1.34, 11.65 ± 1.19, vs 7.91 ± 0.70 in hepatocytes, P < 0.01). FCM showed that mean fluorescence intensity (MFI) and numbers of FITC-CD14 positive cells in the rats with endotoxemia increased obviously at 3, 6, 12 and 24 h when compared with normal control group (43.4%, 70.2%, 91.4%, 32.6% vs 4.5%, P < 0.01).

CONCLUSION: LPS can markedly promote the synthesis of CD14 protein and up-regulate the expression of CD14 mRNA in isolated hepatocytes and hepatic tissue. Liver might be a main source for soluble CD14 production during endotoxemia.

Diagnosis of haploidy and triploidy based on measurement of gene copy number by real-time PCR

We report the development of a method for diagnosis of heterozygous deletions or duplications based on measurement of gene copy number. The method involves amplifications of a test locus with unknown copy number and a reference locus with known copy number using real-time PCR. Progress of the PCR reactions is monitored using fluorigenic probes and a real-time fluorescence detection system. For each reaction, the number of cycles is measured at which a defined threshold fluorescence emission is reached. Using standard curves, the copy number of the test DNA relative to a common standard DNA is determined for each locus. From the ratio of the relative copy numbers, the genomic copy number of the test locus is determined. In order to demonstrate the accuracy and reliability of the method for genetic testing, we analyzed 43 patients with hereditary neuropathy with liability to pressure palsies (HNPP), containing a heterozygous deletion of a 1.5 Mb region on chromosome 17p11.2-p12, eight patients with Charcot-Marie-Tooth disease, containing a heterozygous duplication of the same genomic region, and 50 normal control individuals. As a test locus we analyzed the PMP22 gene located within the 1.5 Mb region. The genomic copy number of the test locus was precisely measured, and the presence or absence of the genomic deletion or duplication was unambiguously diagnosed in all individuals.

Production of the acute-phase protein lipopolysaccharide-binding protein by respiratory type II epithelial cells: implications for local defense to bacterial endotoxins

This study demonstrates for the first time that respiratory epithelial cells are able to produce the acute phase protein lipopolysaccharide (LPS)-binding protein (LBP), which is known to play a central role in the defense to bacterial endotoxins (or LPS). Indications for local presence of LBP in human lung was obtained via reverse transcriptase/polymerase chain reaction that showed LBP messenger RNA (mRNA) expression. Therefore, LBP production by the human lung epithelial cell line A549, a human adenocarcinoma with features of type II pneumocytes, was studied. These cells produced LBP in response to interleukin (IL)-1beta, IL-6, and tumor necrosis factor- alpha, a response that was strongly enhanced by dexamethasone. In addition, LBP mRNA was detected in A549 cells, in increasing amounts as a result of stimulation. The pattern of cytokine-induced LBP production in A549 cells was similar to the pattern in the human liver epithelial cell line HuH-7. Moreover, the molecular weight of A549-derived LBP was approximately 60 kD, which is similar to HuH-7-derived LBP. Biologic activity of LBP produced by A549 cells was evaluated on the basis of its ability to interact with LPS. Further indications that type II alveolar epithelial cells are able to produce LBP were obtained from the observations that the murine lung type II epithelial cell line C10 produced murine LBP, and that isolated human primary type II pneumocytes expressed LBP mRNA, which was enhanced after stimulation of cells. The local production of this endotoxin binding protein by lung epithelial cells might contribute to a highly specific response at the site of exposure to bacteria and bacterial endotoxins.

The use of TaqMan RT-PCR assays for semiquantitative analysis of gene expression in CNS tissues and disease models

TaqMan reverse transcription polymerase chain reaction (RT-PCR) is a recently developed technique which allows the measurement of an accumulating PCR product in real time. In the present study we have validated the use of TaqMan RT-PCR for mRNA localisation studies in human and rat tissues, and for the investigation of gene expression changes in CNS animal models. In human brain, D(2) receptor mRNA was enriched in caudate nucleus and putamen, whilst in rat brain, highest levels of D(2) receptor mRNA expression were observed in striatum and nucleus accumbens, consistent with the known distribution of this receptor in basal ganglia. In a rat model of permanent middle cerebral artery occlusion (pMCAO), endogenous interleukin-1 receptor antagonist (IL-1ra) mRNA was upregulated over 30-fold at 24 h post-lesion in both striatum and cortex ipsilateral to artery occlusion. Brain-derived neurotrophic factor (BDNF) mRNA was transiently upregulated 3.7-fold at 3 h, but not at 24 h or 3 days after induction of cortical spreading depression (CSD) in rats. Our observations in these two animal models using TaqMan RT-PCR were consistent with previous reports using other techniques. In conclusion, TaqMan RT-PCR assays provide a rapid and reliable method for semi-quantitative analysis of gene expression in the nervous system.

Quantitative real-time PCR for the measurement of feline cytokine mRNA

We have developed real-time PCR systems to quantitate feline cytokine gene expression. The method is based on the cleavage of fluorescent dye-labelled probes by the 5'-3' exonuclease activity of the Taq DNA polymerase during PCR and measurement of fluorescence intensity by a Sequence Detection System. The feline-specific TaqMan probes were designed to encompass an intron, thus allowing differentiation of complementary DNA versus genomic DNA amplification products. Quantitative analysis of cytokine cDNA concentrations was performed in comparison to feline GAPDH. Messenger RNA (mRNA) from the universally expressed housekeeping gene GAPDH proved to be useful as an amplification control and allowed for correction of variations in the efficiencies of RNA extraction and reverse transcription. GAPDH mRNAs were readily detectable in cDNAs prepared from unstimulated feline peripheral blood mononuclear cells (PBMCs) and from frozen cell pellets, while cytokines (Interleukin (IL)-4, IL-10, IL-12 p35, IL-12 p40, IFNgamma, IL-16) were expressed at variable amounts. IFNgamma transcription was found to be upregulated in stimulated PBMCs and feline cell lines. The synthesis of cDNA and the performance of the PCR in separate tubes proved to be of superior sensitivity compared to a single-tube based system. The assays described are highly reproducible, require no post-PCR manipulation of the amplicons and permit the analysis of several hundred PCR reactions per day. With this method it is possible to detect and quantify cytokine mRNA expression reliably in small amounts of cells even after storage of samples for at least 5 years.