Association between endotoxemia and blood no in the portal circulation of cirrhotic patients: results of a pilot study.

Pathophysiology of portal vein thrombosis (PVT) in cirrhosis is still not entirely understood. Elevated levels of lipopolysaccharides (LPS) in portal circulation are significantly associated with hypercoagulation, increased platelet activation and endothelial dysfunction. The aim of the study was to investigate if LPS was associated with reduced portal venous flow, the third component of Virchow's triad, and the underlying mechanism. Serum nitrite/nitrate, as a marker of nitric oxide (NO) generation, and LPS were measured in the portal and systemic circulation of 20 patients with cirrhosis undergoing transjugular intrahepatic portosystemic shunt (TIPS) procedure; portal venous flow velocity (PVV) was also measured in each patient and correlated with NO and LPS levels. Serum nitrite/nitrate and LPS were significantly higher in the portal compared to systemic circulation; a significant correlation was found between LPS and serum nitrite/nitrate (R = 0.421; p < 0.01). Median PVV before and after TIPS was 15 cm/s (6-40) and 31 cm/s (14-79), respectively. Correlation analysis of PVV with NO and LPS showed a statistically significant negative correlation of PVV with portal venous NO concentration (R = - 0.576; p = 0.020), but not with LPS. In vitro study with endothelial cells showed that LPS enhanced endothelial NO biosynthesis, which was inhibited by L-NAME, an inhibitor of NO synthase, or TAK-242, an inhibitor of TLR4, the LPS receptor; this effect was accomplished by up-regulation of eNOS and iNOS. The study shows that in cirrhosis, endotoxemia may be responsible for reduced portal venous flow via overgeneration of NO and, therefore, contribute to the development of PVT.

Pioglitazone Ameliorates Acute Endotoxemia-Induced Acute on Chronic Renal Dysfunction in Cirrhotic Ascitic Rats.

Endotoxemia-activated tumor necrosis factor (TNFα)/nuclear factor kappa B (NFκB) signals result in acute on chronic inflammation-driven renal dysfunction in advanced cirrhosis. Systemic activation of peroxisome proliferator-activated receptor gamma (PPARγ) with pioglitazone can suppress inflammation-related splanchnic and pulmonary dysfunction in cirrhosis. This study explored the mechanism and effects of pioglitazone treatment on the abovementioned renal dysfunction in cirrhotic rats. Cirrhotic ascitic rats were induced with renal dysfunction by bile duct ligation (BDL). Then, 2 weeks of pioglitazone treatment (Pio, PPAR gamma agonist, 12 mg/kg/day, using the azert osmotic pump) was administered from the 6th week after BDL. Additionally, acute lipopolysaccharide (LPS, Escherichia coli 0111:B4; Sigma, 0.1 mg/kg b.w, i.p. dissolved in NaCl 0.9%) was used to induce acute renal dysfunction. Subsequently, various circulating, renal arterial and renal tissue pathogenic markers were measured. Cirrhotic BDL rats are characterized by decreased mean arterial pressure, increased cardiac output and portal venous pressure, reduced renal arterial blood flow (RABF), increased renal vascular resistance (RVR), increased relative renal weight/hydroxyproline, downregulated renal PPARγ expression, upregulated renal inflammatory markers (TNFα, NFκB, IL-6, MCP-1), increased adhesion molecules (VCAM-1 and ICAM-1), increased renal macrophages (M1, CD68), and progressive renal dysfunction (increasing serum and urinary levels of renal injury markers (lipocalin-2 and IL-18)). In particular, acute LPS administration induces acute on chronic renal dysfunction (increasing serum BUN/creatinine, increasing RVR and decreasing RABF) by increased TNFα-NFκB-mediated renal inflammatory markers as well as renal M1 macrophage infiltration. In comparison with the BDL+LPS group, chronic pioglitazone pre-treatment prevented LPS-induced renal pathogenic changes in the BDL-Pio+LPS group. Activation of systemic, renal vessel and renal tissue levels of PPARγ by chronic pioglitazone treatment has beneficial effects on the endotoxemia-related TNFα/NFκB-mediated acute and chronic renal inflammation in cirrhosis. This study revealed that normalization of renal and renal arterial levels of PPARγ effectively prevented LPS-induced acute and chronic renal dysfunction in cirrhotic ascitic rats.

The Importance of Food for Endotoxemia and an Inflammatory Response.

Bacterial endotoxin is a potent inflammatory antigen abundant in the human intestine. Endotoxins circulate in the blood at low concentrations in all healthy individuals. Elevated levels of circulatory endotoxins may cause inflammation with the development of chronic disease, either affecting metabolism, neurological disease, or resistance to viral and bacterial infections. The most important endotoxin is LPS, being a superantigen. In this narrative review, the effect of various food components to postprandially elevate circulating LPS and inflammatory markers is described. There is evidence that the intake of food enriched in fat, in particular saturated fat, may elevate LPS and pro-inflammatory markers. This occurs in both normal-weight and obese subjects. In obese subjects, inflammatory markers are already elevated before meal consumption. The importance of food choice for endotoxemia and inflammatory response is discussed.

Effects of a Peripherally Restricted Hybrid Inhibitor of CB1 Receptors and iNOS on Alcohol Drinking Behavior and Alcohol-Induced Endotoxemia.

Alcohol consumption is associated with gut dysbiosis, increased intestinal permeability, endotoxemia, and a cascade that leads to persistent systemic inflammation, alcoholic liver disease, and other ailments. Craving for alcohol and its consequences depends, among other things, on the endocannabinoid system. We have analyzed the relative role of central vs. peripheral cannabinoid CB1 receptors (CB1R) using a "two-bottle" as well as a "drinking in the dark" paradigm in mice. The globally acting CB1R antagonist rimonabant and the non-brain penetrant CB1R antagonist JD5037 inhibited voluntary alcohol intake upon systemic but not upon intracerebroventricular administration in doses that elicited anxiogenic-like behavior and blocked CB1R-induced hypothermia and catalepsy. The peripherally restricted hybrid CB1R antagonist/iNOS inhibitor S-MRI-1867 was also effective in reducing alcohol consumption after oral gavage, while its R enantiomer (CB1R inactive/iNOS inhibitor) was not. The two MRI-1867 enantiomers were equally effective in inhibiting an alcohol-induced increase in portal blood endotoxin concentration that was caused by increased gut permeability. We conclude that (i) activation of peripheral CB1R plays a dominant role in promoting alcohol intake and (ii) the iNOS inhibitory function of MRI-1867 helps in mitigating the alcohol-induced increase in endotoxemia.

Kale supplementation during high fat feeding improves metabolic health in a mouse model of obesity and insulin resistance.

Cruciferous vegetables have been widely studied for cancer prevention and cardiovascular health. Broccoli is the cruciferous vegetable whose phytochemistry and physiological effects have been most extensively studied. Kale (Brassica oleracea var. acephala) appears on lists of 'healthiest, nutrient dense foods' but, there is paucity of data on kale as a functional food. In a 12-week study, we tested the effect of curly green kale on high fat diet (HFD) induced obesity and insulin resistance, lipid metabolism, endotoxemia and inflammation in C57BL/6J mice fed isocaloric diets. Kale supplementation did not attenuate HFD diet induced fat accumulation and insulin resistance (P = ns; n = 9) but, it lowered serum triglycerides, low density lipoprotein (LPL) cholesterol and prevented HFD induced increases in systemic endotoxemia and inflammation (serum LPS and Ccl2) (P<0.01; n = 9). In adipose tissue, kale enhanced the expression of genes involved in adipogenesis (P<0.01; n = 9), reduced the appearance of histologic markers of inflammation, downregulated both the gene expression and protein expression of the adipose tissue specific inflammation markers CD11c and F4/80 (P<0.001; n = 9) and reduced the gene expression of a battery of chemokine C-C motif ligands (Ccl2, Ccl6, Ccl7, Ccl8, Ccl9) and chemokine C-C motif receptors (Ccr2, Ccr3, Ccr5). We conclude that kale vegetable protects against HFD diet induced dysfunction through mechanisms involving lipid metabolism, endotoxemia and inflammation.

Systemic inflammation down-regulates glyoxalase-1 expression: an experimental study in healthy males.

BACKGROUND: Hypoxia and inflammation are hallmarks of critical illness, related to multiple organ failure. A possible mechanism leading to multiple organ failure is hypoxia- or inflammation-induced down-regulation of the detoxifying glyoxalase system that clears dicarbonyl stress. The dicarbonyl methylglyoxal (MGO) is a highly reactive agent produced by metabolic pathways such as anaerobic glycolysis and gluconeogenesis. MGO leads to protein damage and ultimately multi-organ failure. Whether detoxification of MGO into D-lactate by glyoxalase functions appropriately under conditions of hypoxia and inflammation is largely unknown. We investigated the effect of inflammation and hypoxia on the MGO pathway in humans in vivo. METHODS: After prehydration with glucose 2.5% solution, ten healthy males were exposed to hypoxia (arterial saturation 80-85%) for 3.5 h using an air-tight respiratory helmet, ten males to experimental endotoxemia (LPS 2 ng/kg i.v.), ten males to LPS+hypoxia and ten males to none of these interventions (control group). Serial blood samples were drawn, and glyoxalase-1 mRNA expression, MGO, methylglyoxal-derived hydroimidazolone-1 (MG-H1), D-lactate and L-lactate levels, were measured serially. RESULTS: Glyoxalase-1 mRNA expression decreased in the LPS (ß (95%CI); -0.87 (-1.24; -0.50) and the LPS+hypoxia groups; -0.78 (-1.07; -0.48) (P<0.001). MGO was equal between groups, whereas MG-H1 increased over time in the control group only (P=0.003). D-Lactate was increased in all four groups. L-Lactate was increased in all groups, except in the control group. CONCLUSION: Systemic inflammation downregulates glyoxalase-1 mRNA expression in humans. This is a possible mechanism leading to cell damage and multi-organ failure in critical illness with potential for intervention.

Lipopolysaccharide (LPS) induced inflammatory changes to differentially expressed miRNAs of the host inflammatory response.

In veterinary medicine, inflammation in swine is evaluated principally by clinical signs. This method is often unreliable when assessing large animal populations because of inconsistent interpretations of clinical observations. This study examined whether changes in miRNA expression can predict the severity of the inflammatory response in swine after administration of Escherichia coli lipopolysaccharide (LPS). Whole blood from swine challenged with LPS at 0.125 µg/kg to 2.0 µg/kg body weight was collected at 0, 1, 3, and 8 h post LPS-challenge. Mature miRNAs were extracted from plasma and quantitative real-time-PCR (qRT-PCR) was used to evaluate the 84 most abundant swine miRNAs found in plasma. The miRNA changes in expression were assessed using the comparative CT Method (ΔΔCT method) for normalization with an exogenous control. The results revealed that expression of ssc-let-7e-5p, ssc-mir-22-3p, and ssc-miR-146a-5p were the most significantly changed miRNA over the time course. At 1 h post-LPS, ssc-let-7e-5p decreased as the LPS dosage levels increased from 0.125 to 1.0 µg/kg. Similarly, as the LPS doses increased from 0.125 to 0.5 µg/kg, ssc-miR-22-3p levels significantly decreased at 1 h post-LPS. In the 2.0 µg/kg LPS, ssc-miR-146a-5p levels increased between 0 and 3 h post-LPS; however, expression was downregulated with a 145 % decrease from 3 to 8 h. The three miRNA biomarkers suggest potentially useful surrogate endpoints for the evaluation of inflammatory and endotoxemia responses in swine.

Induced normothermia ameliorates the procoagulant host response in human endotoxaemia.

BACKGROUND: Dysregulation of coagulation occurs commonly in sepsis, ranging from mild coagulopathy with decreased platelets to disseminated intravascular coagulation (DIC). We investigated the effect of induced normothermia on coagulation during lipopolysaccharide (LPS)-induced endotoxaemia in healthy volunteers. METHODS: Twelve volunteers received an infusion of bacterial lipopolysaccharide (Escherichia coli; 2 ng kg-1) and were assigned to either induced normothermia or control. Induced normothermia to maintain core temperature at 37°C consisted of external surface cooling, cold i.v. fluids, and medication to reduce shivering (buspirone, clonidine, and magnesium sulphate). The primary outcome was the DIC score (International Society on Thrombosis and Haemostasis guideline). Prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer, plasma von Willebrand factor (vWf), and rotational thromboelastometry (ROTEM) were measured before and 1, 3, 6, and 8 h after LPS infusion. Differences between groups were tested with a mixed effects model. RESULTS: In control subjects, lipopolysaccharide caused a fever, transiently decreased platelet levels and lowered activated partial thromboplastin time, while prolonging prothrombin time and increasing D-Dimer and vWf levels. Normothermia prevented the DIC-score exceeding 4, which occurred in 50% of control subjects. Normothermia also reduced the fall in platelet count by 67x109 L-1([95%CI:27-107]; p=0.002), aPTT (mean difference:3s [95%CI:1-5]; p=0.005) and lowered vWf levels by 89% ([95%CI:6-172]; p=0.03), compared to the fever group. ROTEM measurements were unaffected by lipopolysaccharide. CONCLUSION: In human endotoxaemia, induced normothermia decreases markers of endothelial activation and DIC. Maintaining normothermia may reduce coagulopathy in hyperinflammatory states.

Cardiac and Brainstem Neuroinflammatory Pathways Account for Androgenic Incitement of Cardiovascular and Autonomic Manifestations in Endotoxic Male Rats.

ABSTRACT: Inconsistent reports are available on the role of testosterone in end-organ damage caused by endotoxemia. Here, pharmacologic, surgical, and molecular studies were employed to assess the testosterone modulation of cardiovascular, autonomic, and peripheral and central inflammatory derangements caused by endotoxemia. Studies were performed in conscious male rats preinstrumented with femoral indwelling catheters for the measurement of blood pressure and subjected to castration or pharmacologic interventions that interrupt the biosynthetic cascade of testosterone. Compared with the effects of lipopolysaccharide (10 mg/kg intravenously) in sham operated rats, 2-week castration reduced the lipopolysaccharide-evoked (1) falls in blood pressure, (2) decreases in time- and frequency-domain indices of heart rate variability, (3) shifts in spectral measures of cardiac sympathovagal balance toward parasympathetic dominance, and (4) increases in protein expressions of toll-like receptor-4 and monocyte chemoattractant protein-1 in heart and medullary neurons of the nucleus tractus solitarius and rostral ventrolateral medulla. While the ameliorating actions of castration on endotoxic cardiovascular manifestations were maintained after testosterone replacement, the concomitant inflammatory signals were restored to near-sham levels. The favorable influences of castration on inflammatory and cardiovascular abnormalities of endotoxemia were replicated in intact rats pretreated with degarelix (gonadotropin-releasing hormone receptor blocker) or finasteride (5α-reductase inhibitor) but not formestane (aromatase inhibitor). The data signifies the importance of androgens and its biosynthetic enzymes in cardiovascular and autonomic insults induced by the endotoxic inflammatory response. Clinically, the interruption of testosterone biosynthesis could offer a potential strategy for endotoxemia management.

Storm of Cardiovascular Markers After LPS Administration in Human Volunteers.

Acute infections are associated with an elevated cardiovascular risk. However, little is known about the interactions of acute inflammatory responses and the cardiovascular system. We therefore aimed to evaluate effects of acute inflammatory stimuli mediated by LPS administration on a set of 89 cardiovascular biomarkers. A single-blinded, placebo-controlled cross-over study using the human endotoxin model was performed. Ten healthy men were administered lipopolysaccharide (LPS) or placebo on two different study days after an overnight fast. Eighty-nine different cardiovascular biomarkers were measured repetitively over 48 h. Out of 89 cardiovascular biomarkers, 54 markers were significantly influenced by LPS infusion. The observed biomarker response to inflammation was more pronounced and complex than anticipated. In conclusion, our data show that the cardiovascular system is under enormous distress in response to experimental low-dose inflammation in humans, as demonstrated by a significant effect on 54 of the 89 biomarkers tested.

Therapeutic Rationale for Endotoxin Removal with Polymyxin B Immobilized Fiber Column (PMX) for Septic Shock.

Endotoxin removal therapy with polymyxin B immobilized fiber column (PMX) has been clinically applied for sepsis and septic shock patients since 1994. The effectiveness and usefulness of this therapy have been demonstrated for more than a quarter of a century. However, a documented survival benefit has not yet been demonstrable in a large, multicenter, randomized and controlled trial. Following the findings derived from a large sepsis clinical trial with PMX in North America, a new trial is ongoing to determine if PMX has a long-term survival benefit when administered to septic patients. Another approach to support a survival benefit from intervention with PMX is to utilize a detailed analysis available from a large clinical data base. The endotoxin adsorption capacity of PMX columns in vitro and the effectiveness of PMX columns can be further demonstrable in animal models. The capability of PMX and details of its mechanism of action to intervene in the sepsis cascade and impede organ dysfunction in septic patients is not fully understood. The surface antigen expression in monocytes and neutrophils are improved after PMX therapy. Immunomodulatory effects as a result of endotoxin removal and/or other mechanisms of action have been suggested. These effects and other potential immune effects may explain some of the improved effects upon organ dysfunction of sepsis and septic shock patients. Endotoxemia may be involved in the pathophysiology of other diseases than sepsis. A rapid diagnostic method to detect and target endotoxemia could allow us to practice precision medicine and expand the clinical indications of endotoxin removal therapy.

Frontline Science: The expression of integrin αD ß2 (CD11d/CD18) on neutrophils orchestrates the defense mechanism against endotoxemia and sepsis.

Neutrophil-macrophage interplay is a fine-tuning mechanism that regulates the innate immune response during infection and inflammation. Cell surface receptors play an essential role in neutrophil and macrophage functions. The same receptor can provide different outcomes within diverse leukocyte subsets in different inflammatory conditions. Understanding the variety of responses mediated by one receptor is critical for the development of anti-inflammatory treatments. In this study, we evaluated the role of a leukocyte adhesive receptor, integrin αD ß2 , in the development of acute inflammation. αD ß2 is mostly expressed on macrophages and contributes to the development of chronic inflammation. In contrast, we found that αD -knockout dramatically increases mortality in the cecal ligation and puncture sepsis model and LPS-induced endotoxemia. This pathologic outcome of αD -deficient mice is associated with a reduced number of monocyte-derived macrophages and an increased number of neutrophils in their lungs. However, the tracking of adoptively transferred fluorescently labeled wild-type (WT) and αD-/- monocytes in WT mice during endotoxemia demonstrated only a moderate difference between the recruitment of these two subsets. Moreover, the rescue experiment, using i.v. injection of WT monocytes to αD -deficient mice followed by LPS challenge, showed only slightly reduced mortality. Surprisingly, the injection of WT neutrophils to the bloodstream of αD-/- mice markedly increased migration of monocyte-derived macrophage to lungs and dramatically improves survival. αD -deficient neutrophils demonstrate increased necrosis/pyroptosis. αD ß2 -mediated macrophage accumulation in the lungs promotes efferocytosis that reduced mortality. Hence, integrin αD ß2 implements a complex defense mechanism during endotoxemia, which is mediated by macrophages via a neutrophil-dependent pathway.

Central Administration of Angiotensin-(1-7) Improves Vasopressin Impairment and Hypotensive Response in Experimental Endotoxemia.

Angiotensin-(1-7) [Ang-(1-7)]/Mas receptor is a counter-regulatory axis that counteracts detrimental renin-angiotensin system (RAS) effects, especially regarding systemic inflammation, vasopressin (AVP) release, and hypothalamic-pituitary-adrenal (HPA) activation. However, it is not completely understood whether this system may control centrally or systemically the late phase of systemic inflammation. Thus, the aim of this study was to determine whether intracerebroventricular (i.c.v.) administration of Ang-(1-7) can modulate systemic inflammation through the activation of humoral pathways in late phase of endotoxemia. Endotoxemia was induced by systemic injection of lipopolysaccharide (LPS) (1.5 mg/kg, i.v.) in Wistar rats. Ang-(1-7) (0.3 nmol in 2 µL) promoted the release of AVP and attenuated interleukin-6 (IL-6) and nitric oxide (NO) levels but increased interleukin-10 (IL-10) in the serum of the endotoxemic rats. The central administration of Mas receptor antagonist A779 (3 nmol in 2 µL, i.c.v.) abolished these anti-inflammatory effects in endotoxemic rats. Furthermore, Ang-(1-7) applied centrally restored mean arterial blood pressure (MABP) without affecting heart rate (HR) and prevented vascular hyporesponsiveness to norepinephrine (NE) and AVP in animals that received LPS. Together, our results indicate that Ang-(1-7) applied centrally promotes a systemic anti-inflammatory effect through the central Mas receptor and activation of the humoral pathway mediated by AVP.

Multiplex Fluorescent Bead-Based Immunoassay for the Detection of Cytokines, Chemokines, and Growth Factors.

The comprehensive analysis of serum cytokine levels can be challenging due to low sample volumes and time consuming when using single-target methods like enzyme-linked immunosorbent assay (ELISA). Bead-based detection systems allow the simultaneous detection of multiple analytes using minimal sample volumes. Here we describe the use of a multiplex cytokine, chemokine, and growth factor assay for mouse cytokines in a 96-well format. This assay is based on antibody-coupled fluorescent magnetic beads combined with biotinylated secondary detection antibody followed by fluorescent-tagged streptavidin in a sandwich-like composition. Final assay readout provides the concentrations of 23 different cytokines, chemokines, and growth factors in up to 76 samples.

Serial blood cytokine and chemokine mRNA and microRNA over 48 h are insult specific in a piglet model of inflammation-sensitized hypoxia-ischaemia.

BACKGROUND: Exposure to inflammation exacerbates injury in neonatal encephalopathy (NE). We hypothesized that brain biomarker mRNA, cytokine mRNA and microRNA differentiate inflammation (E. coli LPS), hypoxia (Hypoxia), and inflammation-sensitized hypoxia (LPS+Hypoxia) in an NE piglet model. METHODS: Sixteen piglets were randomized: (i) LPS 2 µg/kg bolus; 1 µg/kg infusion (LPS; n = 5), (ii) Saline with hypoxia (Hypoxia; n = 6), (iii) LPS commencing 4 h pre-hypoxia (LPS+Hypoxia; n = 5). Total RNA was acquired at baseline, 4 h after LPS and 1, 3, 6, 12, 24, 48 h post-insult (animals euthanized at 48 h). Quantitative PCR was performed for cytokines (IL1A, IL6, CXCL8, IL10, TNFA) and brain biomarkers (ENO2, UCHL1, S100B, GFAP, CRP, BDNF, MAPT). MicroRNA was detected using GeneChip (Affymetrix) microarrays. Fold changes from baseline were compared between groups and correlated with cell death (TUNEL) at 48 h. RESULTS: Within 6 h post-insult, we observed increased IL1A, CXCL8, CCL2 and ENO2 mRNA in LPS+Hypoxia and LPS compared to Hypoxia. IL10 mRNA differentiated all groups. Four microRNAs differentiated LPS+Hypoxia and Hypoxia: hsa-miR-23a, 27a, 31-5p, 193-5p. Cell death correlated with TNFA (R = 0.69; p < 0.01) at 1-3 h and ENO2 (R = -0.69; p = 0.01) at 48 h. CONCLUSIONS: mRNA and miRNA differentiated hypoxia from inflammation-sensitized hypoxia within 6 h in a piglet model. This information may inform human studies to enable triage for tailored neuroprotection in NE. IMPACT: Early stratification of infants with neonatal encephalopathy is key to providing tailored neuroprotection. IL1A, CXCL8, IL10, CCL2 and NSE mRNA are promising biomarkers of inflammation-sensitized hypoxia. IL10 mRNA levels differentiated all three pathological states; fold changes from baseline was the highest in LPS+Hypoxia animals, followed by LPS and Hypoxia at 6 h. miR-23, -27, -31-5p and -193-5p were significantly upregulated within 6 h of a hypoxia insult. Functional analysis highlighted the diverse roles of miRNA in cellular processes.

Running at Increasing Intensities in the Heat Induces Transient Gut Perturbations.

PURPOSE: The risk of exercise-induced endotoxemia is increased in the heat and is primarily attributable to changes in gut permeability resulting in the translocation of lipopolysaccharides (LPS) into the circulation. The purpose of this study was to quantify the acute changes in gut permeability and LPS translocation during submaximal continuous and high-intensity interval exercise under heat stress. METHODS: A total of 12 well-trained male runners (age 37 [7] y, maximal oxygen uptake [VO2max] 61.0 [6.8] mL·min-1·kg-1) undertook 2 treadmill runs of 2 × 15-minutes at 60% and 75% VO2max and up to 8 × 1-minutes at 95% VO2max in HOT (34°C, 68% relative humidity) and COOL (18°C, 57% relative humidity) conditions. Venous blood samples were collected at the baseline, following each running intensity, and 1 hour postexercise. Blood samples were analyzed for markers of intestinal permeability (LPS, LPS binding protein, and intestinal fatty acid-binding protein). RESULTS: The increase in LPS binding protein following each exercise intensity in the HOT condition was 4% (5.3 µg·mL-1, 2.4-8.4; mean, 95% confidence interval, P < .001), 32% (4.6 µg·mL-1, 1.8-7.4; P = .002), and 30% (3.0 µg·mL-1, 0.03-5.9; P = .047) greater than in the COOL condition. LPS was 69% higher than baseline following running at 75% VO2max in the HOT condition (0.2 endotoxin units·mL-1, 0.1-0.4; P = .011). Intestinal fatty acid-binding protein increased 43% (2.1 ng·mL-1, 0.1-4.2; P = .04) 1 hour postexercise in HOT compared with the COOL condition. CONCLUSIONS: Small increases in LPS concentration during exercise in the heat and subsequent increases in intestinal fatty acid-binding protein and LPS binding protein indicate a capacity to tolerate acute, transient intestinal disturbance in well-trained endurance runners.

Circulating BMP9 Protects the Pulmonary Endothelium during Inflammation-induced Lung Injury in Mice.

Rationale: Pulmonary endothelial permeability contributes to the high-permeability pulmonary edema that characterizes acute respiratory distress syndrome. Circulating BMP9 (bone morphogenetic protein 9) is emerging as an important regulator of pulmonary vascular homeostasis. Objectives:To determine whether endogenous BMP9 plays a role in preserving pulmonary endothelial integrity and whether loss of endogenous BMP9 occurs during LPS challenge. Methods: A BMP9-neutralizing antibody was administrated to healthy adult mice, and lung vasculature was examined. Potential mechanisms were delineated by transcript analysis in human lung endothelial cells. The impact of BMP9 administration was evaluated in a murine acute lung injury model induced by inhaled LPS. Levels of BMP9 were measured in plasma from patients with sepsis and from endotoxemic mice. Measurements and Main Results: Subacute neutralization of endogenous BMP9 in mice (N = 12) resulted in increased lung vascular permeability (P = 0.022), interstitial edema (P = 0.0047), and neutrophil extravasation (P = 0.029) compared with IgG control treatment (N = 6). In pulmonary endothelial cells, BMP9 regulated transcriptome pathways implicated in vascular permeability and cell-membrane integrity. Augmentation of BMP9 signaling in mice (N = 8) prevented inhaled LPS-induced lung injury (P = 0.0027) and edema (P < 0.0001). In endotoxemic mice (N = 12), endogenous circulating BMP9 concentrations were markedly reduced, the causes of which include a transient reduction in hepatic BMP9 mRNA expression and increased elastase activity in plasma. In human patients with sepsis (N = 10), circulating concentratons of BMP9 were also markedly reduced (P < 0.0001). Conclusions: Endogenous circulating BMP9 is a pulmonary endothelial-protective factor, downregulated during inflammation. Exogenous BMP9 offers a potential therapy to prevent increased pulmonary endothelial permeability in lung injury.

Hepatic-Specific Decrease in the Expression of Selenoenzymes and Factors Essential for Selenium Processing After Endotoxemia.

Background: Selenium (Se) levels decrease in the circulation during acute inflammatory states and sepsis, and are inversely associated with morbidity and mortality. A more specific understanding of where selenoproteins and Se processing are compromised during insult is needed. We investigated the acute signaling response in selenoenzymes and Se processing machinery in multiple organs after innate immune activation in response to systemic lipopolysaccharide (LPS). Methods: Wild type (WT) adult male C57/B6 mice were exposed to LPS (5 mg/kg, intraperitoneal). Blood, liver, lung, kidney and spleen were collected from control mice as well as 2, 4, 8, and 24 h after LPS. Plasma Se concentration was determined by ICP-MS. Liver, lung, kidney and spleen were evaluated for mRNA and protein content of selenoenzymes and proteins required to process Se. Results: After 8 h of endotoxemia, plasma levels of Se and the Se transporter protein, SELENOP were significantly decreased. Consistent with this timing, the transcription and protein content of several hepatic selenoenzymes, including SELENOP, glutathione peroxidase 1 and 4 were significantly decreased. Furthermore, hepatic transcription and protein content of factors required for the Se processing, including selenophosphate synthetase 2 (Sps2), phosphoseryl tRNA kinase (Pstk), selenocysteine synthase (SepsecS), and selenocysteine lyase (Scly) were significantly decreased. Significant LPS-induced downregulation of these key selenium processing enzymes was observed in isolated hepatocytes. In contrast to the acute and dynamic changes observed in the liver, selenoenzymes did not decrease in the lung, kidney or spleen. Conclusion: Hepatic selenoenzyme production and Se processing factors decreased after endotoxemia. This was temporally associated with decreased circulating Se. In contrast to these active changes in the regulation of Se processing in the liver, selenoenzymes did not decrease in the lung, kidney or spleen. These findings highlight the need to further study the impact of innate immune challenges on Se processing in the liver and the impact of targeted therapeutic Se replacement strategies during innate immune challenge.

Serial measurements of Paraoxonase-1 (PON-1) activity in horses with experimentally induced endotoxemia.

BACKGROUND: Paraoxonase-1 (PON-1) is an antioxidant enzyme, whose activity decreases during the acute phase response in many species. Little is known about PON-1 and its role as a negative acute phase protein during septic inflammation in horses, but promising findings about its utility in diagnosing SIRS and predicting the outcome in diseased horses, were recently highlighted. The objective of the study was to investigate the behaviour of PON-1 in horses after experimentally induced endotoxemia. To this aim, PON-1 activity was measured on 66 plasma samples collected from six clinically healthy mares, previously included in another study, before and at multiple time points between 12 and 240 h after intravenous infusion of Escherichia coli O55:B5 lipopolysaccharide (LPS). RESULTS: Compared with baseline values, a progressive transient decrease of PON-1 activity was observed starting from 24 h post-infusion, with lowest values observed between 3 to 7 days post-infusion, followed by a normalisation to pre-infusion levels the tenth day. CONCLUSIONS: The results of this study suggest that measurement and monitoring of PON-1 activity might be useful to evaluate progression and recovery from endotoxemia in horses. Further studies in horses with naturally occurring sepsis are warranted.

Endotoxemia coupled with heightened inflammation predicts future depressive symptoms.

OBJECTIVE: Cross-sectional data have linked gut barrier abnormalities and endotoxemia with depression, even among those without gastrointestinal symptoms. This study examined longitudinal associations between endotoxemia markers and depressive symptoms, as well as the role of inflammation in this relationship. DESIGN: At three annual visits, 315 women (n=209 breast cancer survivors, n = 106 non-cancer patient controls, M=55 years old) completed the Center for Epidemiological Studies Depression questionnaire (CES-D) and provided blood samples to assess inflammatory markers - interleukin-6, tumor necrosis factor-alpha, and C-reactive protein - and endotoxemia markers - lipopolysaccharide-binding protein (LBP), soluble CD14 (sCD14), and their ratio. RESULTS: Adjusting for key demographic variables, health behaviors, visit 1 depressive symptoms, and cancer status and treatment, women with higher visit 1 LBP and LBP/sCD14 had more depressive symptoms at the two subsequent annual visits. Illustrating the notable impact, a woman at the 75th percentile for LBP or LBP/sCD14 at visit 1 was 18 % more likely to report clinically significant depressive symptoms (CES-D ≥16) at follow-up than a woman in the lowest quartile. Cancer status and treatment type did not modulate this relationship. In contrast, visit 1 depressive symptoms did not predict endotoxemia at follow-up. A significant interaction between LBP/sCD14 and inflammatory burden suggested that visit 1 endotoxemia fueled depressive symptoms only in the context of elevated inflammation. CONCLUSION: These results suggest that endotoxemia, combined with systemic inflammation, can drive depressive symptoms. These findings may implicate bacterial endotoxin translocation from the gut to the bloodstream in depression etiology. Interventions that reduce endotoxemia and inflammation may lessen the risk of depression.