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Unlabelled: While nitric oxide (NO) is implicated as an important mediator of hypotension in sepsis and endotoxemia, its role as a mediator of tissue injury in shock is controversial. During porcine endotoxemia (lipopolysaccharide (LPS) 1.7 microg kg(-1) x h(-1) i.v. for 6 h), we compared circulatory and morphological changes in the liver induced by two different NO synthase inhibitors (N(G)-nitro-L-arginine methyl ester, L-NAME, 25 mg x kg(-1) i.v. and aminoethyl-isothiourea, AE-ITU, 10 mg x kg(-1) i.v.), both given after 3 h. LPS induced time-dependent tissue reactions with edema, sinusoidal dilation, packing of red cells and leukocyte infiltration, progressing to endothelial cell and hepatocyte damage, formation of thrombi, and at 6 h widespread necrosis. These changes were similar in all pigs receiving LPS, regardless of treatment with NOS inhibitors. LPS caused significant increases in aspartate aminotransferase (AST), alkaline phosphatase (ALP) and alpha glutathione S-transferase (alpha-GST), L-NAME caused further increases in AST, ALP and alpha-GST, while AE-ITU prevented the late increase in ALP and alpha-GST observed in the other LPS groups. LPS reduced liver blood flow by approximately 40%. L-NAME further reduced flow by approximately 50%, while AE-ITU restored liver blood flow to baseline values.Conclusion: L-NAME in endotoxemia had detrimental effects on liver circulation, while AE-ITU improved liver blood flow and attenuated the late increase in liver enzymes. Liver morphology was unaffected within the 3-h observation time after NOS inhibition. [ABSTRACT FROM AUTHOR]

While nitric oxide (NO) is implicated as an important mediator of hypotension in sepsis and endotoxemia, its role as a mediator of tissue injury in shock is controversial. During porcine endotoxemia (lipopolysaccharide (LPS) 1.7 μg·kg[sup -1]·h[sup -1] i.v. for 6 h), we compared circulatory and morphological changes in the liver induced by two different NO synthase inhibitors (N[sup G]-nitro-L-arginine methyl ester, L-NAME, 25 mg·kg-[sup 1] i.v., and aminoethyl-isothiourea, AE-ITU, 10 mg·kg-[sup 1] i.v.), both given after 3 h. LPS induced time-dependent tissue reactions with edema, sinusoidal dilation, packing of red cells and leukocyte infiltration, progressing to endothelial cell and hepatocyte damage, formation of thrombi, and at 6 h widespread necrosis. These changes were similar in all pigs receiving LPS, regardless of treatment with NOS inhibitors. LPS caused significant increases in aspartate aminotransferase (AST), alkaline phosphatase (ALP) and alpha glutathione S-transferase (α-GST). L-NAME caused further increases in AST, ALP and α-GST, while AE-ITU prevented the late increase in ALP and α-GST observed in the other LPS groups. LPS reduced liver blood flow by [sup ∼]40%. L-NAME further reduced flow by [sup ∼] 50%, while AE-ITU restored liver blood flow to baseline values. Conclusion: L-NAME in endotoxemia had detrimental effects on liver circulation, while AE-ITU improved liver blood flow and attenuated the late increase in liver enzymes. Liver morphology was unaffected within the 3-h observation time after NOS inhibition. [ABSTRACT FROM AUTHOR]

This review highlights the significance of interactions between the microbiota, immune system, nervous and hormonal systems, and the brain on periodontal health and disease. Microorganisms in the microbiota, immune cells, and neurons communicate via homeostatic nervous and hormonal systems, regulating vital body functions. By modulating pro-inflammatory and anti-inflammatory adaptive immune responses, these systems control the composition and number of microorganisms in the microbiota. The strength of these brain-controlled responses is genetically determined but is sensitive to early childhood stressors, which can permanently alter their responsiveness via epigenetic mechanisms, and to adult stressors, causing temporary changes. Clinical evidence and research with humans and animal models indicate that factors linked to severe periodontitis enhance the responsiveness of these homeostatic systems, leading to persistent hyperactivation. This weakens the immune defense against invasive symbiotic microorganisms (pathobionts) while strengthening the defense against non-invasive symbionts at the gingival margin. The result is an increased gingival tissue load of pathobionts, including Gram-negative bacteria, followed by an excessive innate immune response, which prevents infection but simultaneously destroys gingival and periodontal tissues. Thus, the balance between pro-inflammatory and anti-inflammatory adaptive immunity is crucial in controlling the microbiota, and the responsiveness of brain-controlled homeostatic systems determines periodontal health., (© 2024 The Author(s). Periodontology 2000 published by John Wiley & Sons Ltd.)

Background: Cardiovascular (CV) and thermal responses to metabolically demanding multi-day military operations in extreme cold-weather environments are not well described. Characterization of these operations will provide greater insights into possible performance capabilities and cold injury risk., Methods: Soldiers from two cold-weather field training exercises (FTX) were studied during 3-day (study 1, n  = 18, age: 20 ± 1 year, height: 182 ± 7 cm, mass: 82 ± 9 kg) and 4-day (study 2, n  = 10, age: 20 ± 1 year, height: 182 ± 6 cm, mass: 80.7 ± 8.3 kg) ski marches in the Arctic. Ambient temperature ranged from -18 to -4 °C during both studies. Total daily energy expenditure (TDEE, from doubly labeled water), heart rate (HR), deep body ( T pill ), and torso ( T torso ) skin temperature (obtained in studies 1 and 2) as well as finger ( T fing ), toe ( T toe ), wrist, and calf temperatures (study 2) were measured., Results: TDEE was 6821 ± 578 kcal day -1 and 6394 ± 544 for study 1 and study 2, respectively. Mean HR ranged from 120 to 140 bpm and mean T pill ranged between 37.5 and 38.0 °C during skiing in both studies. At rest, mean T pill ranged from 36.0 to 36.5 °C, (lowest value recorded was 35.5 °C). Mean T fing ranged from 32 to 35 °C during exercise and dropped to 15 °C during rest, with some T fing values as low as 6-10 °C. T toe was above 30 °C during skiing but dropped to 15-20 °C during rest., Conclusions: Daily energy expenditures were among the highest observed for a military training exercise, with moderate exercise intensity levels (~65% age-predicted maximal HR) observed. The short-term cold-weather training did not elicit high CV and T pill strain. T fing and T toe were also well maintained while skiing, but decreased to values associated with thermal discomfort at rest.

The magnitude, temporal dynamics, and physiological effects of intestinal microbiome responses to physiological stress are poorly characterized. This study used a systems biology approach and a multiple-stressor military training environment to determine the effects of physiological stress on intestinal microbiota composition and metabolic activity, as well as intestinal permeability (IP). Soldiers ( n = 73) were provided three rations per day with or without protein- or carbohydrate-based supplements during a 4-day cross-country ski-march (STRESS). IP was measured before and during STRESS. Blood and stool samples were collected before and after STRESS to measure inflammation, stool microbiota, and stool and plasma global metabolite profiles. IP increased 62 ± 57% (mean ± SD, P < 0.001) during STRESS independent of diet group and was associated with increased inflammation. Intestinal microbiota responses were characterized by increased α-diversity and changes in the relative abundance of >50% of identified genera, including increased abundance of less dominant taxa at the expense of more dominant taxa such as Bacteroides Changes in intestinal microbiota composition were linked to 23% of metabolites that were significantly altered in stool after STRESS. Together, pre-STRESS Actinobacteria relative abundance and changes in serum IL-6 and stool cysteine concentrations accounted for 84% of the variability in the change in IP. Findings demonstrate that a multiple-stressor military training environment induced increases in IP that were associated with alterations in markers of inflammation and with intestinal microbiota composition and metabolism. Associations between IP, the pre-STRESS microbiota, and microbiota metabolites suggest that targeting the intestinal microbiota could provide novel strategies for preserving IP during physiological stress. NEW & NOTEWORTHY Military training, a unique model for studying temporal dynamics of intestinal barrier and intestinal microbiota responses to stress, resulted in increased intestinal permeability concomitant with changes in intestinal microbiota composition and metabolism. Prestress intestinal microbiota composition and changes in fecal concentrations of metabolites linked to the microbiota were associated with increased intestinal permeability. Findings suggest that targeting the intestinal microbiota could provide novel strategies for mitigating increases in intestinal permeability during stress.

Unlabelled: Soldiers often experience negative energy balance during military operations that diminish whole-body protein retention, even when dietary protein is consumed within recommended levels (1.5-2.0 g·kg·d)., Purpose: The objective of this study is to determine whether providing supplemental nutrition spares whole-body protein by attenuating the level of negative energy balance induced by military training and to assess whether protein balance is differentially influenced by the macronutrient source., Methods: Soldiers participating in 4-d arctic military training (AMT) (51-km ski march) were randomized to receive three combat rations (CON) (n = 18), three combat rations plus four 250-kcal protein-based bars (PRO, 20 g protein) (n = 28), or three combat rations plus four 250-kcal carbohydrate-based bars daily (CHO, 48 g carbohydrate) (n = 27). Energy expenditure (D2O) and energy intake were measured daily. Nitrogen balance (NBAL) and protein turnover were determined at baseline (BL) and day 3 of AMT using 24-h urine and [N]-glycine., Results: Protein and carbohydrate intakes were highest (P < 0.05) for PRO (mean ± SD, 2.0 ± 0.3 g·kg·d) and CHO (5.8 ± 1.3 g·kg·d), but only CHO increased (P < 0.05) energy intake above CON. Energy expenditure (6155 ± 515 kcal·d), energy balance (-3313 ± 776 kcal·d), net protein balance (NET) (-0.24 ± 0.60 g·d), and NBAL (-68.5 ± 94.6 mg·kg·d) during AMT were similar between groups. In the combined cohort, energy intake was associated (P < 0.05) with NET (r = 0.56) and NBAL (r = 0.69), and soldiers with the highest energy intake (3723 ± 359 kcal·d, 2.11 ± 0.45 g protein·kg·d, 6.654 ± 1.16 g carbohydrate·kg·d) achieved net protein balance and NBAL during AMT., Conclusion: These data reinforce the importance of consuming sufficient energy during periods of high energy expenditure to mitigate the consequences of negative energy balance and attenuate whole-body protein loss.

Load carriage (LC) exercise may exacerbate inflammation during training. Nutritional supplementation may mitigate this response by sparing endogenous carbohydrate stores, enhancing glycogen repletion, and attenuating negative energy balance. Two studies were conducted to assess inflammatory responses to acute LC and training, with or without nutritional supplementation. Study 1: 40 adults fed eucaloric diets performed 90-min of either LC (treadmill, mean ± SD 24 ± 3 kg LC) or cycle ergometry (CE) matched for intensity (2.2 ± 0.1 VO2peak L min(-1)) during which combined 10 g protein/46 g carbohydrate (223 kcal) or non-nutritive (22 kcal) control drinks were consumed. Study 2: 73 Soldiers received either combat rations alone or supplemented with 1000 kcal day(-1) from 20 g protein- or 48 g carbohydrate-based bars during a 4-day, 51 km ski march (~45 kg LC, energy expenditure 6155 ± 515 kcal day(-1) and intake 2866 ± 616 kcal day(-1)). IL-6, hepcidin, and ferritin were measured at baseline, 3-h post exercise (PE), 24-h PE, 48-h PE, and 72-h PE in study 1, and before (PRE) and after (POST) the 4-d ski march in study 2. Study 1: IL-6 was higher 3-h and 24-h post exercise (PE) for CE only (mode × time, P < 0.05), hepcidin increased 3-h PE and recovered by 48-h, and ferritin peaked 24-h and remained elevated 72-h PE (P < 0.05), regardless of mode and diet. Study 2: IL-6, hepcidin and ferritin were higher (P < 0.05) after training, regardless of group assignment. Energy expenditure (r = 0.40), intake (r = -0.26), and balance (r = -0.43) were associated (P < 0.05) with hepcidin after training. Inflammation after acute LC and CE was similar and not affected by supplemental nutrition during energy balance. The magnitude of hepcidin response was inversely related to energy balance suggesting that eating enough to balance energy expenditure might attenuate the inflammatory response to military training., (© 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)

The standard clinical method for the assessment of viability in ischemic small intestine is still visual inspection and palpation. This method is non-specific and unreliable, and requires a high level of clinical experience. Consequently, viable tissue might be removed, or irreversibly damaged tissue might be left in the body, which may both slow down patient recovery. Impedance spectroscopy has been used to measure changes in electrical parameters during ischemia in various tissues. The physical changes in the tissue at the cellular and structural levels after the onset of ischemia lead to time-variant changes in the electrical properties. We aimed to investigate the use of bioimpedance measurement to assess if the tissue is ischemic, and to assess the ischemic time duration. Measurements were performed on pigs (n = 7) using a novel two-electrode setup, with a Solartron 1260/1294 impedance gain-phase analyser. After induction of anaesthesia, an ischemic model with warm, full mesenteric arterial and venous occlusion on 30 cm of the jejunum was implemented. Electrodes were placed on the serosal surface of the ischemic jejunum, applying a constant voltage, and measuring the resulting electrical admittance. As a control, measurements were done on a fully perfused part of the jejunum in the same porcine model. The changes in tan δ (dielectric parameter), measured within a 6 h period of warm, full mesenteric occlusion ischemia in seven pigs, correlates with the onset and duration of ischemia. Tan δ measured in the ischemic part of the jejunum differed significantly from the control tissue, allowing us to determine if the tissue was ischemic or not (P < 0.0001, F = (1,75.13) 188.19). We also found that we could use tan δ to predict ischemic duration. This opens up the possibility of real-time monitoring and assessment of the presence and duration of small intestinal ischemia.

Intestinal ischemia is a serious condition that may lead to both local and systemic inflammatory responses. Restoration of blood supply (reperfusion) to ischemic tissues often increases the extent of the tissue injury. Cysteine-rich angiogenic inducer 61 (Cyr61)/CCN1 is an extracellular matrix-associated signaling protein that has diverse functions. CCN1 is highly expressed at sites of inflammation and wound repair, and may modify cell responses. This study aimed to investigate regulation and cellular distribution of CCN1 in intestinal ischemia/reperfusion (I/R) injury in pigs. After intestinal I/R, increased expression of CCN1 was detected by quantitative RT-PCR, Western blot analysis and immunohistochemistry compared with non-ischemic intestine. Immunoflorescence staining revealed that CCN1 was mainly up-regulated in intestinal mucosa after intestinal I/R. Microvillus epithelial cells and vascular endothelial cells were strongly positive for CCN1 in intestinal I/R, while natural killer cells and/or subsets of neutrophils were only modestly positive for CCN1. Furthermore, blood samples taken from the portal and caval veins during ischemia and after reperfusion showed no change of the CCN1 levels, indicating that CCN1 was locally regulated. In conclusion, these observations show, for the first time, that the CCN1 molecule is up-regulated in response to intestinal I/R in a local manner., (© The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

Background and Objective: Early life adverse events may influence susceptibility/resistance to chronic inflammatory diseases later in life by permanently dysregulating brain-controlled immune-regulatory systems. We have investigated the impact of infant-mother separation during early postnatal life on the severity of experimental periodontitis, as well as systemic stress and immune responses, in adulthood., Material and Methods: Pups of periodontitis resistant Lewis rats were separated from their mothers for 3 h daily during postnatal days 2-14 (termed maternal deprivation; MD), separated for 15 min daily during the same time period (termed handling; HD), or left undisturbed. As adults, their behaviour was tested in a novel stressful situation, and ligature-induced periodontitis applied for 21 days. Two h before sacrifice all rats were exposed to a gram-negative bacterial lipopolysaccharide (LPS) challenge to induce a robust immune and stress response., Results: Compared to undisturbed controls, MD rats developed significantly more periodontal bone loss as adults, whereas HD rats showed a tendency to less disease. MD and HD rats exhibited depression-like behaviour in a novel open field test, while MD rats showed higher glucocorticoid receptor (Gr) expression in the hippocampus, and HD rats had altered methylation of genes involved in the expression of hippocampal Gr. LPS provoked a significantly lower increase in circulating levels of the cytokine TGF-1β in MD and HD rats, but there were no significant differences in levels of the stress hormone corticosterone., Conclusion: Stressful environmental exposures in very early life may alter immune responses in a manner that influences susceptibility/resistance to periodontitis.

Physiological consequences of winter military operations are not well described. This study examined Norwegian soldiers (n = 21 males) participating in a physically demanding winter training program to evaluate whether short-term military training alters energy and whole-body protein balance, muscle damage, soreness, and performance. Energy expenditure (D2(18)O) and intake were measured daily, and postabsorptive whole-body protein turnover ([(15)N]-glycine), muscle damage, soreness, and performance (vertical jump) were assessed at baseline, following a 4-day, military task training phase (MTT) and after a 3-day, 54-km ski march (SKI). Energy intake (kcal·day(-1)) increased (P < 0.01) from (mean ± SD (95% confidence interval)) 3098 ± 236 (2985, 3212) during MTT to 3461 ± 586 (3178, 3743) during SKI, while protein (g·kg(-1)·day(-1)) intake remained constant (MTT, 1.59 ± 0.33 (1.51, 1.66); and SKI, 1.71 ± 0.55 (1.58, 1.85)). Energy expenditure increased (P < 0.05) during SKI (6851 ± 562 (6580, 7122)) compared with MTT (5480 ± 389 (5293, 5668)) and exceeded energy intake. Protein flux, synthesis, and breakdown were all increased (P < 0.05) 24%, 18%, and 27%, respectively, during SKI compared with baseline and MTT. Whole-body protein balance was lower (P < 0.05) during SKI (-1.41 ± 1.11 (-1.98, -0.84) g·kg(-1)·10 h) than MTT and baseline. Muscle damage and soreness increased and performance decreased progressively (P < 0.05). The physiological consequences observed during short-term winter military training provide the basis for future studies to evaluate nutritional strategies that attenuate protein loss and sustain performance during severe energy deficits.

Background: Hepcidin, a peptide that is released into the blood in response to inflammation, prevents cellular iron export and results in declines in iron status. Elevated serum and urinary levels of hepcidin have been observed in athletes following exercise, and declines in iron status have been reported following prolonged periods of training. The objective of this observational study was to characterize the effects of an occupational task, military training, on iron status, inflammation, and serum hepcidin., Findings: Volunteers (n = 21 males) included Norwegian Soldiers participating in a 7-day winter training exercise that culminated in a 3-day, 54 km ski march. Fasted blood samples were collected at baseline, on day 4 (PRE, prior to the ski march), and again on day 7 (POST, following the ski march). Samples were analyzed for hemoglobin, serum ferritin, soluble transferrin receptor (sTfR), interleukin-6 (IL-6), and serum hepcidin. Military training affected inflammation and serum hepcidin levels, as IL-6 and hepcidin concentrations increased (P < 0.05) from the baseline to POST (mean ± SD, 9.1 ± 4.9 vs. 14.5 ± 8.4 pg/mL and 6.5 ± 3.5 vs. 10.2 ± 6.9 ng/mL, respectively). Iron status was not affected by the training exercise, as sTfR levels did not change over the course of the 7-day study., Conclusions: Military training resulted in significant elevations in IL-6 and serum hepcidin. Future studies should strive to identify the role of hepcidin in the adaptive response to exercise, as well as countermeasures for the prevention of chronic or repeated elevations in serum hepcidin due to exercise or sustained occupational tasks which may result in longer term decrements in iron status.

Background: Impaired haemostasis following shock and tissue trauma is frequently detected in the trauma setting. These changes occur early, and are associated with increased mortality. The mechanism behind trauma-induced coagulopathy (TIC) is not clear. Several studies highlight the crucial role of fibrinogen in posttraumatic haemorrhage. This study explores the coagulation changes in a swine model of early TIC, with emphasis on fibrinogen levels and utilization of fibrinogen., Methods: A total of 18 landrace pigs were anaesthetized and divided into four groups. The Trauma-Shock group (TS) were inflicted bilateral blast femoral fractures with concomitant soft tissue injury by a high-energy rifle shot to both hind legs, followed by controlled exsanguination. The Shock group (S) was exposed to shock by exsanguination, whereas a third group was exposed to trauma only (T). A fourth group (C) served as control. Physiological data, haematological measurements, blood gas analyses and conventional coagulation assays were recorded at baseline and repeatedly over 60 minutes. Thrombelastometry were performed by means of the tissue factor activated ExTEM assay and the platelet inhibiting FibTEM assay. Data were statistically analysed by repeated measurements analyses method., Results: A significant reduction of fibrinogen concentration was observed in both the TS and S groups. INR increased significantly in the S group and differed significantly from the TS group. Maximum clot firmness (MCF) of the ExTEM assay was significantly reduced over time in both TS and S groups. In the FibTEM assay a significant shortening of the clotting time and an increase in MCF was observed in the TS group compared to the S group., Conclusion: Despite a reduction in clotting capability measured by ExTEM MCF and a reduced fibrinogen concentration, extensive tissue trauma may induce an increased fibrin based clotting activity that attenuates the hypocoagulable tendency in exsanguinated animals.

Background: Both glucocorticosteroids and biologic drugs such as the tumor necrosis factor (TNF)-α antagonist infliximab are used often in the treatment of rheumatoid arthritis or inflammatory bowel disease. In severe disease, or if allergic reactions occur during treatment with infliximab, combined therapy with these drugs often is instituted. Combining infliximab and glucocorticosteroids may increase substantially the risk of severe opportunistic infections or dissemination of malignant tumors because of their additive effects as immunosuppressants., Methods: In a whole-blood in vitro model, we studied the influence of different doses of infliximab and hydrocortisone, either separately or in combination, on the synthesis of selected cytokines after stimulation with lipopolysaccharide (LPS)., Results: Hydrocortisone in therapeutic serum concentrations significantly inhibited the expression of a majority of the cytokines tested. Infliximab, in serum concentrations relevant to clinical situations, inhibited TNF-α activity significantly. This effect was potentiated when infliximab was combined with hydrocortisone. Similar effects were found using a low dose of infliximab combined with hydrocortisone. Infliximab alone inhibited the expression of the cytokines interleukin (IL)-1 receptor antagonist, monocyte chemoattractant protein-1, IL-8, and IL-12. Hydrocortisone in combination with low-dose infliximab potentiated the suppressive effects on TNF-α, IL-1β, IL-8, and macrophage inflammatory protein-1α synthesis., Conclusions: Immune-modulating effects of infliximab were found both in clinically relevant doses and, most notably, in low doses reflecting serum concentrations found commonly in patients several months after the last injection. Infliximab potentiates the suppressive effects of hydrocortisone on cytokine synthesis.

Background: Toll-like receptor 4 (TLR4), especially expressed on monocytes/macrophages, connects microbial and sterile innate immune activation. Lipopolysaccharide (LPS) from Gram-negative bacteria and several endogenous molecules, among others saturated fatty acids (SFAs), are able to induce signalling through this receptor. Downstream inflammatory cytokines orchestrate the immune response. Our aim was to investigate how long-lasting multifactorial stress affects Gram-negative signalling and search for possible correlations between cytokine production and TLR4 expression or SFA concentration., Methods: Eight healthy males were studied during a 7-day ranger-training course with semi-continuous physical strain, together with energy and sleep restrictions. Blood drawn on days 0, 3, 5 and 7 was incubated ex vivo for 6 h with or without LPS 10 ng/mL, whereupon surface expression of TLR4 on CD14⁺ monocytes and supernatant concentrations of inflammatory cytokines (TNF-α, IL-1β and IL-6) were measured. In addition, plasma free fatty acids were quantified., Results: Monocyte TLR4 expression was elevated throughout the course (p < 0.05 vs. baseline). Corresponding results were found for SFAs. The concentration of TNF-α increased significantly on day 3 and thereafter normalized, and a similar pattern was seen for IL-1β. No correlations were found between cytokine concentrations and monocyte TLR4 expression or plasma SFAs., Conclusion: Multifactorial stress significantly affected ex vivo production of TNF-α and monocyte surface expression of TLR4. In addition, mobilization of fat resulted in increased plasma concentrations of SFAs. No associations between inflammatory cytokines and monocyte TLR4 expression or SFAs were found.

Background: Alterations in body temperature may influence immune system function and consequently affect the risk of infection and inflammatory diseases. Lipopolysaccharide (LPS) from gram-negative bacteria induces production of inflammatory cytokines after ligand binding to Toll-like receptor 4 (TLR4) on immune cells (especially monocytes/ macrophages). Our aim was to explore how clinically relevant hypo- and hyperthermia affect this signalling in an ex vivo whole blood model, and investigate if the cytokine response was correlated with monocyte TLR4 expression level., Methods: Blood from 11 healthy volunteers was incubated with LPS 10 ng/ml for 6 h at 33, 37 or 40°C. The concentrations of selected pro-inflammatory (tumour necrosis factor-α (TNF-α) and interleukin (IL)-1β) and anti-inflammatory (IL-10) cytokines were measured in plasma, and the surface expression of TLR4 was quantified on CD14 + monocytes., Results: Monocyte TLR4 expression and plasma IL-1β were inversely related to temperature. The TNF-α production was unaffected by hypothermia but increased significantly during hyperthermia, whereas plasma IL-10 was significantly reduced during both hypo- and hyperthermic incubation. No correlation was found between TLR4 expression and cytokine concentrations. During hypothermia, the TNF-α/IL-10 and IL-1β/IL-10 ratios increased seven and nine times, respectively. Hyperthermia increased the TNF-α/IL-10 ratio, but to a lesser extent (doubling), whereas the IL-1β/IL-10 ratio remained unchanged., Conclusion: Hypothermia significantly changed the cytokine ratios in the pro-inflammatory direction. In comparison, the effect of hyperthermia was sparse, with a modest increase in the TNF-α/IL-10 ratio only. No association was found between LPS-stimulated cytokine production and TLR4 expression on CD14 + monocytes.

Background and Objective: The immune system is an important player in the pathophysiology of periodontitis. The brain controls immune responses via neural and hormonal pathways, and brain-neuro-endocrine dysregulation may be a central determinant for pathogenesis. Our current knowledge also emphasizes the central role of sensory nerves. In line with this, we wanted to investigate how desensitization of peptidergic sensory neurons influences the progression of ligature-induced periodontitis, and, furthermore, how selected cytokine and stress hormone responses to Gram-negative bacterial lipopolysaccharide (LPS) stimulation are affected., Material and Methods: Resiniferatoxin (RTX; 50 μg/kg) or vehicle was injected subcutaneously on days 1, 2, and 3 in stress high responding and periodontitis-susceptible Fischer 344 rats. Periodontitis was induced 2 days thereafter. Progression of the disease was assessed after the ligatures had been in place for 20 days. Two h before decapitation all rats received LPS (150 μg/kg i.p.) to induce a robust immune and stress response., Results: Desensitization with RTX significantly reduced bone loss as measured by digital X-rays. LPS provoked a significantly higher increase in serum levels of the pro-inflammatory cytokine tumour necrosis factor (TNF)-α, but lower serum levels of the anti-inflammatory cytokine interleukin (IL)-10 and the stress hormone corticosterone., Conclusions: In this model RTX-induced chemical desensitization of sensory peptidergic neurons attenuated ligature-induced periodontitis and promoted a shift towards stronger pro-inflammatory cytokine and weaker stress hormone responses to LPS. The results may partly be explained by the attenuated transmission of immuno-inflammatory signals to the brain. In turn, this may weaken the anti-inflammatory brain-derived pathways.

The question of specific immunomodulating qualities of hypertonic saline (HTS) has not been settled. It has proven difficult to distinguish between immunomodulation directly attributable to HTS and influence because of favorable circulatory effects. The nature of immune activator may also play a role. In a whole-blood model, we have investigated these relations further, with special emphasize on osmolalities usually found after recommended dosing. Blood from 10 healthy donors was exposed to osmolalities ranging from 295 to 480 mOsm/kg and stimulated with the two clinically relevant stimulators peptidoglycan (1 µg/mL) or LPS (10 ng/mL) for 6 h at 37°C. Leukocyte response was evaluated by measuring selected cytokines in the supernatant. Moderate hyperosmolality alone boosted the release of CXCL8/IL-8. The peptidoglycan-stimulated synthesis of pivotal proinflammatory cytokines was inhibited in an osmolality-dependent way, but statistically significant only at osmolalities above those attained after routine use of HTS, i.e., 310 mOsm/kg or greater: IL-6 (P < 0.05 at 315 mOsm/kg), IL-1ß, and TNF-α (P < 0.05 at 335 mOsm/kg). Similar effects were seen for the chemokine CCL3 and the anti-inflammatory cytokine IL-10. In contrast, the effects in cells stimulated with LPS were either lower or absent. Thus, osmolalities usually found after clinical use of HTS only modestly influenced the selected immune parameters, regardless of stimulator.

The hepatic artery buffer response, which is lost during endotoxemia, plays a central role in the autoregulation of liver perfusion. A temporarily decreased synthesis of nitric oxide during early endotoxemia might be responsible for this dysfunction; hence exogenous administration of nitric oxide could reestablish the autoregulation of hepatic blood flow and help prevent hepatic damage later in septic shock. Fifteen pigs were treated with lipopolysaccharide +/- the nitric oxide donor nitroprusside-sodium via the portal vein. Hemodynamics were measured, and serum chemistry and liver biopsies for nitric oxide synthase expression were obtained. Lipopolysaccharide decreased arterial liver perfusion after 5 hours by 38% (p = .012), which was reversed by addition of nitroprusside (8%). Administration of nitroprusside preserved an increase of 28% in hepatic arterial upon portal vein flow reduction (p < .001). Nitroprusside maintained mRNA levels of constitutive nitric oxide synthase in liver tissue which were decreased by lipopolysaccharide (p = .026 vs. p = .114) and tempered the burst in inducible nitric oxide synthase expression at t = 3 hours. The early administration of the nitric oxide donor sodium nitroprusside during endotoxemia is able to reestablish the autoregulatory response of the hepatic artery following reduction of hepatic blood flow. This beneficial effect might help to prevent subsequent hepatic damage in the course of abdominal sepsis.

Background: The incidence of gram-positive and mixed bacterial infections in surgical patients has increased, and there has been an alarming rise in the number of drug-resistant bacteria. Peptidoglycan (PepG) is a cell wall component of gram-positive bacteria that stimulates inflammatory responses both ex vivo and in vivo. The systemic effects of PepG on inflammation have not been studied in a large animal model., Methods: Anesthetized pigs were subjected to 8-h continuous intravenous infusions of lipopolysaccharide (LPS) (4 mcg/kg/h), PepG (40 mcg/kg/h), LPS plus PepG, or saline. The concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8, and IL-10 were measured in the plasma prior to infusion (time 0) and thereafter every second hour until the end of the experiments. Heparinized whole blood samples drawn at time 0 and after a 6-h infusion of LPS or PepG were incubated ex vivo with PepG (10 mcg/mL), LPS (10 ng/mL), or a combination of PepG and LPS to study the immunologic consequences of systemic inflammation. Concentrations of TNF-alpha, IL-8, and IL-1beta were measured in the supernatant liquids., Results: In vivo, there was transient upregulation of TNF-alpha after infusion of LPS, PepG, or the combination. Interleukin-6 and IL-8 were upregulated by LPS but not by PepG. In vitro studies of whole blood obtained at time 0 revealed a synergistic effect of LPS and PepG on the release of TNF-alpha. Incubation of whole blood obtained after 6 h of infusion of LPS or PepG revealed tolerance and cross-tolerance between the two bacterial components in the induction of TNF-alpha, IL-8, and IL-1beta., Conclusions: Peptidoglycan is a potent inducer of TNF-alpha in this large animal model. Peptidoglycan and LPS synergized to increase the formation of the proinflammatory cytokine TNF-alpha. The study demonstrates for the first time the development of tolerance and cross-tolerance between LPS and PepG in a large animal model. These phenomena could be of importance for the signs and symptoms of sepsis.

Both exhaustive physical exertion and starvation have been reported to induce depression of immune function. The aim of the present study was to investigate the inflammatory environment and state of activation and mediator-producing potential of circulating leukocytes during prolonged physical activity with concomitant energy and sleep deprivation. Eight well-trained males were studied during 7 days of semi-continuous physical activity. Sleep was restricted to about 1 h/24 h, energy intake to 1.5- 3.0 MJ/24 h. Blood was drawn at 07.00 A.M.: on days 0, 2, 4, and 7. Plasma levels of inflammation markers were measured. The response of circulating leukocytes to lipopolysaccharide (LPS; 1 microg mL(-1)), and the effect of added hydrocortisone (10 and 100 nmol L(-1)), were measured in the supernatant after 3 h of incubation in an ex vivo whole blood model. Activation of leukocytes steadily increased as measured by plasma matrix metalloproteinase-9, tumour necrosis factor-alpha, interleukin-1beta, and interleukin-6. Inhibitors of systemic inflammation were either unaltered (tissue inhibitor of matrix metalloproteinase-1) or elevated (plasma interleukin-1 receptor antagonist). Cortisol levels increased on days 2 and 4, but thereafter reverted to baseline values. The leukocytes responded to LPS activation with increasing release of inflammatory cytokines throughout the study period. The anti-inflammatory potency of hydrocortisone decreased. Prolonged multifactorial stress thus activated circulating immune cells and primed them for an increased response to a subsequent microbial challenge.