Experimental Endotoxemia Research Articles

Effects of anti-inflammatory drug treatment on psychological and bodily sickness symptoms during experimental endotoxemia: A randomized controlled study in healthy volunteers

Effects of anti-inflammatory drug treatment on psychological and bodily sickness symptoms during experimental endotoxemia: A randomized controlled study in healthy volunteers

Dietary d-Lactate Intake Facilitates Inflammatory Resolution by Modulating M1 Macrophage Polarization.

Given the d-lactate dehydrogenase (D-LDH) deficiency, L- but not d-lactate is assumed to be the physiological isomer in mammals. Paradoxically, many fermented foods (e.g., yogurt, sauerkraut, cheeses) often contain substantial amounts of d-lactate. In the present study, dietary d-lactate may be a previously unrecognized nutrient aiding in inflammatory resolution is hypothesized. The anti-inflammatory properties of d-lactate are evaluated in experimental colitis and endotoxemia. Oral administration of d-lactate favorably affects acute inflammation in two different mouse models. Analysis of lactate-the lactate receptor (the hydroxycarboxylic acid receptor 1 HCA1, formerly GPR81) signal axis in inflammation is performed in primary peritoneal macrophages and wild-type (WT) or GPR81 knockout (KO) mice. GPR81 KO mice are susceptible to endotoxic shock than WT mice, while d-lactate exerts its anti-inflammatory activities in a GPR81-dependent manner. Mechanistically, the activation of lactate-GPR81 axis may suppress LPS-TLR4 signaling to modulate M1 macrophage polarization. Although D-LDH deficiency in mammals impairs d-lactate clearance, it might prolong its plasma terminal half-life, and thus provide a pharmacokinetic advantage of d-lactate over l-lactate. This study highlights housekeeping function of the lactate-GPR81 axis in inflammation control, and suggests that dietary intake of d-lactate may underlie Metchnikoff's probiotic yogurt theory of life prolongation.

Recombinant thrombomodulin may protect cardiac capillary endothelial glycocalyx through promoting Glypican-1 expression under experimental endotoxemia

IntroductionMyocardial dysfunction occurs in patients with sepsis due to vascular endothelial injury. Recombinant human thrombomodulin (rhTM) attenuates vascular endothelial injuries through endothelial glycocalyx (eGC) protection. HypothesisWe hypothesized that rhTM attenuates myocardial dysfunction via the inhibition of vascular endothelial injury during sepsis. MethodsTen-week-old male C57BL6 mice were injected intraperitoneally with 20 mg/kg of lipopolysaccharide (LPS). In rhTM-treated mice, rhTM was injected intraperitoneally at 3 and 24 h after LPS injection. Saline was injected intraperitoneally as control. To assess for eGC injury, intensity score was measured 48 h after the LPS injection. To confirm vascular endothelial injuries, ultrastructural analysis was performed using scanning (SEM) and transmission electron microscopy (TEM). ResultsThe survival rate of the rhTM group at 48 h after LPS injection was significantly higher than that of the control group (68% vs. 17%, p < 0.05). The serum level of troponin I in the rhTM group was lower than that in the control (2.2 ± 0.4 ng/dL vs 9.4 ± 1.1 ng/dL, p < 0.05). The expression of interleukin-6 (IL-6) was attenuated in the rhTM-treated group than in the control (65.3 ± 15.3 ng/mL vs 226.3 ± 19.4 ng/mL, p < 0.05). The serum concentration of syndecan-1, a marker of glycocalyx damage, was significantly decreased 48 h post-administration of LPS in the rhTM-treated group than in the control group. In ultrastructural analysis using SEM and TEM, eGC peeled off from the surface of the capillary lumen in the control. Conversely, the eGC injury was attenuated in the rhTM group. Gene set enrichment analysis revealed that osteomodulin, osteoglycin proline/arginine-rich end leucine-rich repeat protein, and glypican-1, which are proteoglycans, were preserved by rhTM treatment. Their protein expression was retained in endothelial cells. ConclusionrhTM attenuates sepsis-induced myocardial dysfunction via eGC protection.

Cellular distribution of C-C motif chemokine ligand 2 like immunoreactivities in frontal cortex and corpus callosum of normal and lipopolysaccharide treated animal

BackgroundC-C motif chemokine ligand 2 (CCL2) is reported to be involved in the pathogenesis of various neurological and/or psychiatric diseases. Tissue or cellular expression of CCL2, in normal or pathological condition, may play an essential role in recruiting monocytes or macrophages into targeted organs, and be involved in a certain pathogenic mechanism. However, few studies focused on tissue and cellular distribution of the CCL2 peptide in brain grey and white matters (GM, WM), and the changes of the GM and WM cellular CCL2 level in septic or endotoxic encephalopathy was not explored. Hence, the CCL2 cellular distribution in the front brain cortex and the corpus callosum (CC) was investigated in the present work by using immunofluorescent staining.Results(1) CCL2 like immunoreactivity (CCL2-ir) in the CC is evidently higher than the cortex. When the measurement includes ependymal layer attached to the CC, CCL2-ir intensity is significantly higher than cortex. (2) Structures in perivascular areas, most of them are GFAP positive, contribute major CCL2-ir positive profiles in both GM and WM, but apparently more in the CC, where they are bilaterally distributed in the lateral CC between the cingulate cortex and ventricles. (3) The neuron-like CCL2-ir positive cells in cortex are significantly more than in the CC, and that number is significantly increased in the cortex following systemic lipopolysaccharide (LPS), but not in the CC. (4) In addition to CCL2-ir positive perivascular rings, more CCL2-ir filled cashew shape elements are observed, probably inside of microvasculature, especially in the CC following systemic LPS. (5) Few macrophage/microglia marker-Iba-1 and CCL2-ir co-labeled structures especially the soma is found in normal cortex and CC; the co-localizations are significantly augmented following systemic LPS, and co-labeled amoeba like somata are presented. (6) CCL2-ir and astrocyte marker GFAP or Iba-1 double labeled structures are also observed within the ependymal layer. No accumulation of neutrophils was detected.ConclusionThere exist differences in the cellular distribution of the CCL2 peptide in frontal cortex GM and subcortical WM–CC, in both the physiological condition and experimental endotoxemia. Which might cause different pathological change in the GM and WM.

Galectin-9 Mediates the Therapeutic Effect of Mesenchymal Stem Cells on Experimental Endotoxemia.

Endotoxemia remains a major cause of mortality in the intensive care unit, but the therapeutic strategy is still lacking. Mesenchymal stem cell (MSC) was reported with a tissue-oriented differentiation ability and an excellent immunoregulatory capacity. However, the immunity signaling pathways that govern MSC modulation effect are not completely understood. In our current study, MSCs (2.5 × 105 /ml) were obtained and stimulated with IFN-γ (20 ng/ml) for 72 h. Gal-9 expression on MSCs was measured by ELISA, RT-PCR, flow cytometry, and immunofluorescence, respectively. Experimental endotoxemia was induced by LPS injection (10 mg/kg, i. p.) followed by the treatment with Gal-9 high-expressing MSCs, unmodified MSCs, and Gal-9 blocking MSCs. Therapeutic effects of MSCs were assessed by monitoring murine sepsis score, survival rate, splenocyte proportion rate, inflammatory mediator levels, and pathological manifestations. The results showed that Gal-9 expressed in MSCs, and this expression was increased in a dose-dependent manner after pre-stimulating with IFN-γ. Adoptive transfer of Gal-9 high-expressing MSCs into modeling mice significantly alleviated endotoxemia symptoms and multi-organ pathological damages. Splenocyte analysis indicated that Gal-9 high-expressing MSCs could promote macrophage polarization to M2-subtype and boost Treg generation. Moreover, there were also attenuated pro-inflammatory mediator expressions (TNF-α, IL-1β, IFN-γ, and iNOS), and increased anti-inflammatory mediator expressions (T-SOD and IL-35) in the sera and damaged organ homogenates. Additionally, we found a higher expression of Gal-9 in liver, lung, and kidney homogenate. Taken together, this study reveals that the optimized immunoregulatory effect of MSCs is strongly correlated with Gal-9 high expression, which provides a novel idea for the investigation of MSC immunomodulatory mechanisms and offers a potential strategy for the treatment of endotoxemia in clinical settings.

Effects of nitroglycerin and flunixin meglumine on circulating inflammatory, cardiovascular and hepatorenal biomarkers of ovine experimental endotoxemia model

Owing to the importance of endotoxemia and its risks, several studies have been conducted to better understand the pathophysiological processes of this disease, and many treatments have been suggested. Nitroglycerin is one of the drugs recommended for the treatment of endotoxemia and its therapeutic effects in some researches have been evaluated in human and animal models. However, there are no comprehensive studies on the effects of nitroglycerin on different circulating inflammatory, cardiovascular and hepatorenal biomarkers following endotoxemia in sheep; therefore, the present experiment was conducted to evaluate the anti-inflammatory effects of two different doses of nitroglycerin compared to the standard dose of flunixin meglumine in the treatment of endotoxemia in sheep. Hence, 25 clinically healthy 1-year old Iranian fat-tailed ewes were randomly divided into 5 equal groups, comprising NTG 0.2, NTG 0.4, Flnx, Ctrl+, and Ctrl-. Lipopolysaccharide from Escherichia coli serotype O55:B5 at 0.4 μg/kg was intravenously administered to the ewes. Flunixin meglumine (at 2.2 mg/kg) and nitroglycerin (at 0.2 and 0.4 μg/kg) were administrated to Flnx, NTG 0.2 and NTG 0.4 groups, respectively. All the ewes were clinically evaluated before and 1.5, 3, 3.5, 4, 4.5, 6 and 24 h after lipopolysaccharide injection, and blood samplings were also performed at those hours. Serum concentrations of haptoglobin, serum amyloid A, tumor necrosis factor-alpha, interferon-gamma, total antioxidant status, malondialdehyde, superoxide dismutase, glutathione peroxidase, creatine kinase-MB, cardiac lactate dehydrogenase, cardiac troponin-I, homocysteine, total bilirubin, aspartate aminotransferase, alanine transaminase, and creatinine were measured. Serum concentrations of acute phase proteins, inflammatory cytokines, oxidative stress, cardiovascular, hepatic and renal biomarkers, and clinical parameters were significantly increased following the induction of endotoxemia in the groups receiving lipopolysaccharide. The results indicated that nitroglycerin at both 0.2 and 0.4 μg/kg did not play an effective role in reducing inflammatory biomarkers and could not reduce circulating hepatic biomarkers following endotoxemia. However, nitroglycerin at 0.4 μg/kg significantly reduced circulating cardiac and renal biomarkers compared to 0.2 μg/kg and flunixin meglumine at 2.2 mg/kg. Clinical evaluations also demonstrated that nitroglycerin could not reduce the heart rate and body temperature compared to flunixin meglumine but significantly reduced respiratory rates at 0.4 μg/kg. In conclusion, nitroglycerin at 0.2 and 0.4 μg/kg could not alleviate inflammatory processes and oxidative stress. Nitroglycerin at 0.2 and 0.4 μg/kg also had suitable effects on reducing the serum concentration of cardiovascular and renal biomarkers, but it was not effective on circulating hepatic indices. Therefore, nitroglycerin at the doses used in this study could not be suggested as an effective drug in reducing inflammatory and hepatic biomarkers which were elevated during endotoxemia in sheep.

Un-fractionated heparin counteracts the systemic inflammatory responses and multiple organ damages caused by endotoxaemia in sheep.

BackgroundEndotoxaemia is believed to be a major cause of mortality and there are several therapeutic regimens for the treatment of this situation.ObjectivesThe present experimental study was conducted to evaluate acute phase response, cardiovascular and hepatorenal damages following the treatment of Ovine experimental endotoxaemia model employing unfractionated heparin (UFH).Materials and MethodsTwenty clinically healthy 1‐year‐old fat‐tailed ewes were randomly divided into four equal groups, comprising UFH 200, UFH 400, Ctrl+ and Ctrl‐. Lipopolysaccharide (LPS) from Escherichia coli serotype O55:B5 at 0.4 μg/kg was administered intravenously to the ewes. UFH (at 200 and 400 IU/kg) was administrated to the UFH 200 and UFH 400 groups, respectively. All the ewes were evaluated clinically before and 1.5, 3, 4.5, 6 and 24 hours after LPS injection. Blood samplings were also performed at those hours. We measured serum concentrations of haptoglobin, interferon‐gamma, total antioxidant status, malondialdehyde, cardiac lactate dehydrogenase, cardiac troponin‐I, total bilirubin, alanine transaminase and creatinine. Serum concentrations of acute phase response, cardiovascular, hepatic and renal biomarkers and clinical parameters increased significantly following the induction of endotoxaemia in the groups receiving LPS.ResultsThe significantly lowest concentrations of these parameters at hours 4.5 and 6 among the treatment groups belonged to the UFH 400 sheep.ConclusionsUFH could act as an anti‐inflammatory mediator by decreasing inflammatory cytokines and acute phase proteins, modulating oxidative stress biomarkers and reducing multiple organ dysfunction following endotoxaemia in a dose–dependent manner. Furthermore, the anti‐inflammatory effects of UFH at 400 IU/kg were significantly higher than another dose. This research examined the effect of two doses of UFH and higher doses may have more anti‐inflammatory effects that require further studies.

THE RESEARCH OF TLR4 INVOLVEMENT IN SIGNALING PATHWAYS ACTIVATED IN MURINE OVARIAN CELLS UNDER THE INFLUENCE OF LIPOPOLYSACCHARIDE

Toll-like receptor 4 (TLR4) is a widely described transmembrane protein involved in the inflammatory process. Bacterial infection is one of the main factors influencing the change in TLR4 expression. At the same time, the level of TLR4 expression directly correlates with the severity of the process, which in some cases allows considering these receptors as an early markers of infection. Early it was shown disruption of ovarian cell functions under the condi-tions of experimental endotoxemia in mice. Pathological changes of follicular environment of oocytes resulted in impairment of oocyte meiotic maturation. However, involvement of TLR4 in activation of signaling pathways in ovar-ian cells under the influence of lipopolysaccharide (LPS), requires careful study. In the present work we have investi-gated pharmacological effect of TAK242 (inhibitor of TLR4) on oocyte meiotic maturation in vitro under the influ-ence of LPS. The study was done on cumulus oocyte complexes (COCs) and oocytes, denuded from cumulus cells, which were isolated from ovaries of Albino mice. It was shown that LPS inhibited meiotic maturation in vitro of COCs and cumulus-denuded oocytes. However, 15 min pretreatment with TLR4 inhibitor (ТАК242) with the subsequent ad-dition of LPS to the culture medium, improved meiotic maturation of both COCs and cumulus-denuded oocytes. More-over, simultaneous exposure to ТАК242 and LPS did not show any significant differences in meiotic maturation of both COCs and cumulus-denuded oocytes compared with 15 min pretreatment with ТАК242. The results obtained may indicate the presence of TLR4 on murine oocytes and cumulus cells. Also the results can serve as the basis for the re-search of feasibility of therapeutic use of TLR4 inhibitors in diseases in the course of which interaction between TLR4 and its ligands (in particular LPS) occur.

Effect of erythromycin on abomasal emptying in suckling lambs with experimental endotoxemia

Abomasal hypomotility and consequently a decrease in abomasal emptying rate is one of the most important factors in ruminant abomasal disorders. Endotoxemia is clinically recognized by abnormalities in cardiovascular function, renal failure, decreased gastrointestinal motility and shock. This can lead to bloating and sudden death in lambs that have not received enough colostrum. The aim of the study was to investigate the effect of erythromycin treatment on abomasal emptying rate in endotoxemic lambs. Fifteen suckling lambs arranged in 3 groups (n = 5) were studied in this study. Endotoxemia was induced in two groups (Positive control and Erythromycin) at 0.1 μg/kg body weight LPS in 10 mL normal saline over 5 min IV and erythromycin was injected to erythromycin group at 8.8 mg/kg BW IM. Negative control received 2 mL normal saline IM. Abomasal emptying rate was assessed by acetaminophen absorption test, which was fed with milk at 50 mg/kg BW, 30 min after each treatment. Samples were collected at 15 min intervals up to 240 min and abomasal emptying rate was assessed for each group. Results showed there were significant differences in Cmax, Tmax and AUC among groups (endotoxemia groups and control group) (P < 0.05), confirming a decrease in abomasal emptying rate in lambs with endotoxemia. The results also indicated that compared to affected lambs not treated with erythromycin, abomasal emptying rate was significantly higher in lambs treated with erythromycin that means erythromycin increased abomasal emptying rate (P < 0.05).

Low molecular weight heparin reduces acute phase response and multiple organ dysfunction following Ovine experimental endotoxemia model

Endotoxemia is one of the most common inflammatory situations leading to death of ruminants. Owing to the importance of this condition, several therapeutic regimens have been proposed, evaluated and implemented to treat endotoxemia. It has recently been suggested that low molecular weight heparin may be effective in treating endotoxemia. Thus, the present experimental study was conducted to evaluate the acute phase response and multiple organ dysfunction following the treatment of the Ovine experimental endotoxemia model employing this compound. In this regard, 20 clinically healthy 1-year old Iranian fat-tailed ewes were randomly divided into 4 equal groups, comprising LMWH 50, LMWH 100, Ctrl+, and Ctrl-. Lipopolysaccharide from Escherichia coli serotype O55:B5 at 0.4 μg/kg was intravenously administered to the ewes. Low molecular weight heparin (at 50 and 100 IU/kg) was administrated to LMWH 50 and LMWH 100 groups, respectively. Positive control (Ctrl+) received lipopolysaccharide and treated only by intravenous fluid without any drugs, and negative control (Ctrl-) only received intravenous fluids without lipopolysaccharide or any drugs. All the ewes were clinically evaluated before and 1.5, 3, 4.5, 6 and 24 h after lipopolysaccharide injection, and blood samplings were also performed at those hours. Serum concentrations of serum amyloid A, tumor necrosis factor-alpha, superoxide dismutase, glutathione peroxidase, creatine kinase-MB, homocysteine, total bilirubin, aspartate aminotransferase, and creatinine were measured. Serum concentrations of acute phase proteins, inflammatory cytokines, oxidative stress, cardiovascular, hepatic and renal biomarkers, and clinical parameters were significantly increased following the induction of endotoxemia in the groups receiving lipopolysaccharide. Significantly lower concentration of these markers was observed at 4.5 and 6 h after lipopolysaccharide administration in the sheep treated with LMWH compared to the Ctrl + group. In conclusion, low molecular weight heparin could act as an anti-inflammatory drug by decreasing cytokines and acute phase proteins, modulating oxidative stress biomarkers, and by reducing multiple organ dysfunction following the induction of endotoxemia by Escherichia coli serotype O55:B5 in Iranian fat-tailed sheep in a dose-dependent manner. Furthermore, the anti-inflammatory effects of low molecular weight heparin at 100 IU/kg were significantly higher than 50 IU/kg in the treatment of endotoxemic sheep.

Regulation of emotions during experimental endotoxemia

Regulation of emotions during experimental endotoxemia

Advantages and methodological considerations of experimental endotoxemia in humans – Towards a standardized procedure for its application in PNI

Advantages and methodological considerations of experimental endotoxemia in humans – Towards a standardized procedure for its application in PNI

Choline or CDP-choline restores hypotension and improves myocardial and respiratory functions in dogs with experimentally – Induced endotoxic shock

Endotoxin shock is associated with severe impairments in cardiovascular and respiratory functions. We showed previously that choline or cytidine-5′-diphosphocholine (CDP-choline) provides beneficial effects in experimental endotoxin shock in dogs. The objective of the present study was to determine the effects of choline or CDP-choline on endotoxin-induced cardiovascular and respiratory dysfunctions.Dogs were treated intravenously (i.v.) with saline or endotoxin (LPS, 0.1 mg/kg) 5 min before i.v. infusion of saline, choline (20 mg/kg) or CDP-choline (70 mg/kg). Blood pressure, cardiac rate, myocardial and left ventricular functions, respiratory rate, blood gases, serum electrolytes and cardiac injury markers were determined before and at 0.5-48 h after endotoxin. Plasma tumor necrosis factor alpha (TNF-α), high mobility group box-1 (HMGB1), catecholamine and nitric oxide (NO) levels were measured 2 h and 24 h after the treatments.Endotoxin caused immediate and sustained reductions in blood pressure, cardiac output, pO2 and pH; changes in left ventricular functions, structure and volume parameters; and elevations in heart rate, respiratory rate, pCO2 and serum electrolytes (Na, K, Cl, Ca and P). Endotoxin also resulted in elevations in blood levels of cardiac injury markers, TNF-α, HMGB1, catecholamine and NO. In choline- or CDP-choline-treated dogs, all endotoxin effects were much smaller in magnitude and shorter in duration than observed values in controls.These data show that treatment with choline or CDP-choline improves functions of cardiovascular and respiratory systems in experimental endotoxemia and suggest that they may be useful in treatment of endotoxin shock in clinical setting.

Near-Infrared Spectroscopy-Derived Dynamic Cerebral Autoregulation in Experimental Human Endotoxemia-An Exploratory Study.

Cerebral perfusion may be altered in sepsis patients. However, there are conflicting findings on cerebral autoregulation (CA) in healthy participants undergoing the experimental endotoxemia protocol, a proxy for systemic inflammation in sepsis. In the current study, a newly developed near-infrared spectroscopy (NIRS)-based CA index is investigated in an endotoxemia study population, together with an index of focal cerebral oxygenation.Methods: Continuous-wave NIRS data were obtained from 11 healthy participants receiving a continuous infusion of bacterial endotoxin for 3 h (ClinicalTrials.gov NCT02922673) under extensive physiological monitoring. Oxygenated–deoxygenated hemoglobin phase differences in the (very)low frequency (VLF/LF) bands and the Tissue Saturation Index (TSI) were calculated at baseline, during systemic inflammation, and at the end of the experiment 7 h after the initiation of endotoxin administration.Results: The median (inter-quartile range) LF phase difference was 16.2° (3.0–52.6°) at baseline and decreased to 3.9° (2.0–8.8°) at systemic inflammation (p = 0.03). The LF phase difference increased from systemic inflammation to 27.6° (12.7–67.5°) at the end of the experiment (p = 0.005). No significant changes in VLF phase difference were observed. The TSI (mean ± SD) increased from 63.7 ± 3.4% at baseline to 66.5 ± 2.8% during systemic inflammation (p = 0.03) and remained higher at the end of the experiment (67.1 ± 4.2%, p = 0.04). Further analysis did not reveal a major influence of changes in several covariates such as blood pressure, heart rate, PaCO2, and temperature, although some degree of interaction could not be excluded.Discussion: A reversible decrease in NIRS-derived cerebral autoregulation phase difference was seen after endotoxin infusion, with a small, sustained increase in TSI. These findings suggest that endotoxin administration in healthy participants reversibly impairs CA, accompanied by sustained microvascular vasodilation.

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 (β (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.

THE STATE OF THE CELLS OF THE IMMUNE SYSTEM IN EXPERIMENTAL IMMUNE-MEDIATED INFLAMMATION OF VARIOUS GENESIS

Relevance. Immune-mediated inflammation of various genesis plays a significant pathogenetic role in autoimmune, allergic, inflammatory and infectious diseases.&#x0D; The objective of the work was a comparative study of the functional status and pathways of cell death of natural and adaptive immunity in mice under the conditions of experimental hyperimmunocomplexemia and endotoxemia to identify the features and common cellular mechanisms of these pathologies.&#x0D; Materials and methods. Hyperimmunocomplexemia was simulated by six-fold immunization of female mice with increasing doses of the antigen, bovine serum albumin (BSA), once a week; the endotoxemia model was induced by the administration of lipopolysaccharide (LPS).&#x0D; Results. The use of both BSA and LPS led to a systemic inflammatory process with significant neutrophilia with a shift of the leukogram to the left. There was a significant increase in the functional and metabolic activity of nonspecific resistance cells. Genotoxic stress was observed in thymus cells and lymph nodes with significant DNA damage, decreased viability, and a significant increase in necrotic death. Violation of the plasma membrane integrity of primary alteration and the release of the cellular content outside has a strong pro-inflammatory and immunogenic effect, which can lead to further intensification of the disease and an increase in its duration with a tendency to chronicity of the pathological process.&#x0D; Conclusions. Thus, both models are characterized by the development of immune-inflammatory processes that lead to significant DNA damage and cell death, which can cause a new round of intensification of necrotic, inflammatory and autoimmune reactions in the body.

Wearable Patch Heart Rate Variability Is an Early Marker of Systemic Inflammation During Experimental Human Endotoxemia.

Early diagnosis and treatment can reduce the risk of organ failure and mortality in systemic inflammatory conditions. Heart rate variability (HRV) has potential for early identification of the onset of systemic inflammation, as it may detect changes in sympathetic nervous system activity resulting from the developing inflammatory response before clinical signs appear. With the use of new methodologies, we investigated the onset and kinetics of HRV changes as well as several inflammatory parameters and symptoms during experimental human endotoxemia, a model of systemic inflammation in humans in vivo. Healthy volunteers were intravenously administered LPS (n = 15) or placebo (n = 15). HRV was determined using a wireless wearable device, and parameters low to high frequency (LF:HF) ratio, root mean square of the successive differences (RMSSD), and standard deviation of normal-to-normal R-R intervals (SDNN)were calculated through 1-min-rolling 6-min windows. Plasma cytokine levels and flu-like symptoms and vital signs were serially assessed. The increase in LF:HF ratio, reflecting sympathetic predominance, was more pronounced in the LPS group compared to the placebo group, with the difference becoming statistically significant 65 min following LPS administration (1.63 [1.42-1.83] vs. 1.28 [1.11-1.44], P = 0.005). Significant between-group differences in RMSSD and SDNN were observed from 127 to 140 min post-LPS administration onwards, respectively. Plasma cytokine levels showed significant between-group differences staring 60 min post-LPS. For symptom score, heart rate, temperature, and diastolic blood pressure, significant differences compared with the placebo group were observed at 90, 118, 120, and 124 min post-LPS, respectively. In a controlled human model of systemic inflammation, elevations in the LF:HF ratio followed very shortly after elevations in plasma cytokine levels and preceded onset of flu-like symptoms and alterations in vital signs. HRV may represent a promising non-invasive tool for early detection of a developing systemic inflammatory response.

Role of the Transcription Factor BTB and CNC Homology 1 in a Rat Model of Acute Liver Injury Induced by Experimental Endotoxemia.

Hepatic oxidative stress plays an important role in the pathogenesis of several acute liver diseases, and free heme is thought to contribute to endotoxemia-induced acute liver injury. The heme oxygenase 1 (HO-1) gene is upregulated and the δ-aminolevulinate synthase (ALAS1) gene is downregulated in the rat liver following lipopolysaccharide (LPS) treatment. BTB and CNC homology 1 (Bach1) is a heme-responsive transcription factor that normally represses HO-1 expression. In this study, we evaluated the changes in HO-1, ALAS1, and Bach1 expression and nuclear Bach1 expression in rat livers following intravenous LPS administration (10 mg/kg body weight). LPS significantly upregulated HO-1 mRNA and downregulated ALAS1 mRNA in the rat livers, suggesting that hepatic free heme concentrations are increased after LPS treatment. Bach1 mRNA was strongly induced after LPS injection. In contrast, nuclear Bach1 was significantly but transiently decreased after LPS treatment. Rats were also administered hemin (50 mg/kg body weight) intravenously to elevate heme concentrations, which decreased nuclear Bach1 levels. Our results suggest that elevated hepatic free heme may be associated with a decline of nuclear Bach1, and induction of Bach1 mRNA may compensate for the decreased nuclear Bach1 after LPS treatment in the rat liver.

Human in vivo neuroimaging to detect reprogramming of the cerebral immune response following repeated systemic inflammation

Despite increasing evidence that immune training within the brain may affect the clinical course of neuropsychiatric diseases, data on cerebral immune tolerance are scarce. This study in healthy volunteers examined the trajectory of the immune response systemically and within the brain following repeated lipopolysaccharide (LPS) challenges. Five young males underwent experimental human endotoxemia (intravenous administration of 2 ng/kg LPS) twice with a 7-day interval. The systemic immune response was assessed by measuring plasma cytokine levels. Four positron emission tomography (PET) examinations, using the translocator protein (TSPO) ligand 18F-DPA-714, were performed in each participant, to assess brain immune cell activation prior to and 5 hours after both LPS challenges. The first LPS challenge caused a profound systemic inflammatory response and resulted in a 53% [95%CI 36–71%] increase in global cerebral 18F-DPA-714 binding (p < 0.0001). Six days after the first challenge, 18F-DPA-714 binding had returned to baseline levels (p = 0.399). While the second LPS challenge resulted in a less pronounced systemic inflammatory response (i.e. 77 ± 14% decrease in IL-6 compared to the first challenge), cerebral inflammation was not attenuated, but decreased below baseline, illustrated by a diffuse reduction of cerebral 18F-DPA-714 binding (-38% [95%CI -47 to -28%], p < 0.0001). Our findings constitute evidence for in vivo immunological reprogramming in the brain following a second inflammatory insult in healthy volunteers, which could represent a neuroprotective mechanism. These results pave the way for further studies on immunotolerance in the brain in patients with systemic inflammation-induced cerebral dysfunction.

Endothelial Glycocalyx Disorders May Be Associated With Extended Inflammation During Endotoxemia in a Diabetic Mouse Model.

In diabetes mellitus (DM) patients, the morbidity of infectious disease is increased, and these infections can easily progress from local to systemic infection. Sepsis is a characteristic of organ failure related to microcirculation disorders resulting from endothelial cell injury, whose most frequent comorbidity in patients is DM. The aim of the present study was to evaluate the influence of infection on DM-induced microvascular damage on inflammation and pulmonary endothelial structure using an experimental endotoxemia model. Lipopolysaccharide (LPS; 15 mg/kg) was injected intraperitoneally into 10-week-old male C57BLKS/J Iar- + leprdb/leprdb (db/db) mice and into C57BLKS/J Iar–m + / + leprdb (db/ +) mice, which served as the littermate non-diabetic control. At 48 h after LPS administration, the survival rate of db/db mice (0%, 0/10) was markedly lower (P < 0.05) than that of the db/ + mice (75%, 18/24), whereas the survival rate was 100% in both groups 24 h after LPS administration. In control mice, CD11b-positive cells increased at 6 h after LPS administration; by comparison, the number of CD11b-positive cells increased gradually in db/db mice until 12 h after LPS injection. In the control group, the number of Iba-1-positive cells did not significantly increase before and at 6, 12, and 24 h after LPS injection. Conversely, Iba-1-positive cells continued to increase until 24 h after LPS administration, and this increase was significantly greater than that in the control mice. Expression of Ext1, Csgalnact1, and Vcan related to endothelial glycocalyx synthesis was significantly lower in db/db mice than in the control mice before LPS administration, indicating that endothelial glycocalyx synthesis is attenuated in db/db/mice. In addition, ultrastructural analysis revealed that endothelial glycocalyx was thinner in db/db mice before LPS injection. In conclusion, in db/db mice, the endothelial glycocalyx is already injured before LPS administration, and migration of inflammatory cells is both delayed and expanded. This extended inflammation may be involved in endothelial glycocalyx damage due to the attenuation of endothelial glycocalyx synthesis.