Increased Plasma IL-6 Research Articles

High-intensity interval training attenuates the exercise-induced increase in plasma IL-6 in response to acute exercise

This aims of this study were to investigate the effects of carbohydrate availability during endurance training on the plasma interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-alpha response to a subsequent acute bout of high-intensity interval exercise. Three groups of recreationally active males performed 6 weeks of high-intensity interval running. Groups 1 (LOW+GLU) and 2 (LOW+PLA) trained twice per day, 2 days per week, and consumed a 6.4% glucose or placebo solution, respectively, before every second training session and at regular intervals throughout exercise. Group 3 (NORM) trained once per day, 4 days per week, and consumed no beverage during training. Each group performed 50 min of high-intensity interval running at the same absolute workloads before and after training. Muscle glycogen utilization in the gastrocnemius muscle during acute exercise was reduced (p < 0.05) in all groups following training, although this was not affected by training condition. Plasma IL-6 concentration increased (p < 0.05) after acute exercise in all groups before and after training. Furthermore, the magnitude of increase was reduced (p < 0.05) following training. This training-induced attenuation in plasma IL-6 increase was similar among groups. Plasma IL-8 concentration increased (p < 0.05) after acute exercise in all groups, although the magnitude of increase was not affected (p > 0.05) by training. Acute exercise did not increase (p > 0.05) plasma TNF-alpha when undertaken before or after training. Data demonstrate that the exercise-induced increase in plasma IL-6 concentration in response to customary exercise is attenuated by previous exercise training, and that this attenuation appears to occur independent of carbohydrate availability during training.

The role of aldosterone in mediating the dependence of angiotensin hypertension on IL-6

Knockout (KO) of IL-6 has been shown to attenuate ANG II hypertension, and mineralocorticoid receptors (MR) have been reported to contribute to the increase in IL-6 during acute ANG II infusion. This study determined whether that MR action is sustained with chronic ANG II infusion and whether it plays a role in mediating ANG II hypertension. ANG II infusion (90 ng/min) increased plasma IL-6 from 1.6 +/- 0.6 to 22.7 +/- 2.2 and 19.9 +/- 3.2 pg/ml on days 7 and 14, respectively, and chronic MR blockade with spironolactone attenuated that only at day 7 (7.2 +/- 2.2 pg/ml). ANG II increased MAP (19 h/day with telemetry) approximately 40 mmHg, but in ANG II+spironolactone mice (25 or 50 mg*kg(-1)*day(-1)), mean arterial pressure (MAP) was not significantly different despite a tendency for lower pressure the first 6 days. To isolate further the mineralocorticoid link to IL-6 and blood pressure, DOCA-salt hypertension was induced in IL-6 KO and wild-type (WT) mice. Plasma IL-6 increased from 4.1 +/- 1.7 to 34.5 +/- 7.0 pg/ml by day 7 of DOCA treatment in the WT mice but was back to control levels by day 14. An IL-6 bioassay using the murine B9, B-cell hybridoma cell line demonstrated that plasma IL-6 measurements reflected actual IL-6 bioactivity. The hypertension was not different and virtually superimposable in WT vs. IL-6 KO mice, averaging 145 +/- 2 and 144 +/- 3 mmHg, respectively. Both experiments confirm chronic stimulation of IL-6 by mineralocorticoids but show that it is transient. In addition, IL-6 was not required for mineralocorticoid hypertension. This suggests that aldosterone contributes to the increase in plasma IL-6 in the early stage of ANG II hypertension but that the blood pressure actions of IL-6 in that model are linked most likely to ANG II rather than aldosterone.

Acute hyperinsulinemia raises plasma interleukin-6 in both nondiabetic and type 2 diabetes mellitus subjects, and this effect is inversely associated with body mass index

Hyperinsulinemia is a characteristic of type 2 diabetes mellitus (T2DM) and is believed to play a role in the low-grade inflammation seen in T2DM. The main aim was to study the effect of hyperinsulinemia on adipokines in individuals with different levels of insulin resistance, glycemia, and obesity. Three groups of sex-matched subjects were studied: young healthy subjects (YS; n = 10; mean age, 26 years; body mass index [BMI], 22 kg/m 2), patients with T2DM (DS; n = 10; 61 years; BMI, 27 kg/m 2), and age- and BMI-matched controls to DS (CS; n = 10; 60 years; BMI, 27 kg/m 2). Plasma concentrations of adipokines were measured during a hyperinsulinemic euglycemic clamp lasting 4 hours. Moreover, insulin-stimulated glucose uptake in isolated adipocytes was analyzed to address adipose tissue insulin sensitivity. Plasma interleukin (IL)-6 increased significantly ( P ≤ .01) in all 3 groups during hyperinsulinemia. However, the increase was smaller in both DS ( P = .06) and CS ( P < .05) compared with YS (∼2.5-fold vs ∼4-fold). A significant increase of plasma tumor necrosis factor (TNF) α was observed only in YS. There were only minor or inconsistent effects on adiponectin, leptin, and high-sensitivity C-reactive protein levels during hyperinsulinemia. Insulin-induced rise in IL-6 correlated negatively to BMI ( P = .001), waist to hip ratio ( P = .05), and baseline (fasting) insulin ( P = .03) and IL-6 ( P = .02) levels and positively to insulin-stimulated glucose uptake in isolated adipocytes ( P = .07). There was no association with age or insulin sensitivity. In a multivariate analysis, also including T2DM/no T2DM, an independent correlation (inverse) was found only between BMI and fold change of IL-6 ( r 2 = 0.41 for model, P < .005). Hyperinsulinemia per se can produce an increase in plasma IL-6 and TNF α, and this can potentially contribute to the low-grade inflammation seen in obesity and T2DM. However, obesity seems to attenuate the ability of an acute increase in insulin to further raise circulating levels of IL-6 and possibly TNF α.

Hyperlipidemia Could Activate Platelet and Induce the Production of Plasma Inflammatory Factors in Rabbits, Which Lead to Atherosclerosis

Background: It had been proved by epidemiology and clinical trials that hypercholesterolemia (HC) and atherosclerosis (AS) had close relations. Lipid could take part in many pathological processes of the AS. Platelets played an important role in this process as an inflammatory mediator. We Chose Platelet aggregation maximum (PAG(M)) and plasma P-selectin as the index of platelet activation, try to explore the transfer of platelet activation and lymphocyte inflammatory reaction in atherosclerosis.Design: We set up the rabbit hyperlipidemia atherosclerosis model through 12 weeks' hyper lipid feeding. PAG(M), concentrations of plasma P-selectin, Interleukin (IL)- 6, IL-1β, tumor necrosis factor (TNF)-α and mRNA expression of these factors in the lymphocyte were measured at 0 week, 6th week and 12th week time point.Results: At the 6th week time point of the hyper lipid feeding, the rabbit had elevated PAG(M) (68.12%±4.73% vs. 62.67%±3.13%; P=0.002, n=20). The PAG(M) was maintained in the high level at 12th week time point (68.83%±3.35% vs. 62.67%±3.13%; P=0.001, n=20). At the 6th week time point of the hyper lipid feeding, the rabbit had elevated plasma P-selectin, IL-6, IL-1β and TNF-α (6th week vs. 0 week, n=20, P-selectin P=0.005, IL-6 P=0.000, IL-1β P=0.001, TNF-α P=0.001). The expressions of IL-6/mRNA, IL-1β/mRNA and TNF-α/mRNA in lymphocytes were elevated too (6th week vs. 0 week, n=20, IL-6/mRNA P=0.000, IL-1β/mRNA P=0.002, TNF-α/mRNA P=0.000). At the 12th week time point, all of the parameters were maintained in the high level, while there had no significant difference between 12th week time point and 6th week time point.Conclusion: Hyperlipidemia could activate platelet. Increased PAG(M) and plasma P-selectin represented the platelet activation. Hyperlipidemia could induce the production of plasma IL-6, IL-1β and TNF-α. The increased plasma IL-6, IL-1β and TNF-α were partly from the lymphocyte secretion because The IL-1β/mRNA, IL-6/mRNA and TNF-α/mRNA expression of lymphocyte elevated. So in rabbit hyperlipidemia atherosclerosis model, platelet activation and inflammatory factors increasing was the main mechanism, while the lymphocyte took part in the inflammatory process.

Activation of Central Nervous System Inflammatory Pathways by Interferon-Alpha: Relationship to Monoamines and Depression

Interferon (IFN)-alpha has been used to study the effects of innate immune cytokines on the brain and behavior in humans. The degree to which peripheral administration of IFN-alpha accesses the brain and is associated with a central nervous system (CNS) inflammatory response is unknown. Moreover, the relationship among IFN-alpha-associated CNS inflammatory responses, neurotransmitter metabolism, and behavior has yet to be established. Twenty-four patients with hepatitis C underwent lumbar puncture and blood sampling after approximately 12 weeks of either no treatment (n = 12) or treatment with pegylated IFN-alpha 2b (n = 12). Cerebrospinal fluid (CSF) and blood samples were analyzed for proinflammatory cytokines and their receptors as well as the chemokine, monocyte chemoattractant protein-1 (MCP-1), and IFN-alpha. Cerebrospinal fluid samples were additionally analyzed for monoamine metabolites and corticotropin releasing hormone. Depressive symptoms were assessed using the Montgomery Asberg Depression Rating Scale. Interferon-alpha was detected in the CSF of all IFN-alpha-treated patients and only one control subject. Despite no increases in plasma IL-6, IFN-alpha-treated patients exhibited significant elevations in CSF IL-6 and MCP-1, both of which were highly correlated with CSF IFN-alpha concentrations. Of the immunologic and neurotransmitter variables, log-transformed CSF concentrations of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA), were the strongest predictor of depressive symptoms. Log-transformed CSF concentrations of IL-6, but not IFN-alpha or MCP-1, were negatively correlated with log-transformed CSF 5-HIAA (r(2) = -.25, p < .05). These data indicate that a peripherally administered cytokine can activate a CNS inflammatory response in humans that interacts with monoamine (serotonin) metabolism, which is associated with depression.

Plasma cytokine concentration changes induced by the antitumor agents dipterinyl calcium pentahydrate (DCP) and related calcium pterins

Analysis of plasma cytokine concentration changes determined that oral dosing with the antitumor agent (1:4 mol:mol) calcium pterin (CaPterin) increased plasma IL-10, decreased plasma IL-6, and decreased plasma IFN- γ concentrations in nude mice with MDA-MB-231 xenograph tumors [Moheno, P., Pfleiderer, W., Dipasquale, A.G., Rheingold, A.L., Fuchs, D., 2008. Cytokine and IDO metabolite changes effected by calcium pterin during inhibition of MDA-MB-231 xenograph tumors in nude mice. Int. J. Pharm. 355, 238–248]. A further analysis, reported here, of plasma cytokine concentration changes in nude mice with the same tumor xenographs treated with dipterinyl calcium pentahydrate (DCP), (1:2 mol:mol) calcium pterin, and CaCl 2·2H 2O has been carried out. The measured cytokines included: IL-1 β, IL-2, IL-4, IL-6, IL-10, IL-12, IFN- γ, and TNF- α. The major preliminary findings from the analyses of these data are that (1) the overall relative tumor volumes for the treatments correlated significantly with a full study antitumor plasma cytokine pattern (fsAPCP), a composite measure consisting of decreased plasma IL-6 and increased IL-4 concentrations, and (2) DCP induces a significant threshold antitumor response strongly correlated to a derived DCP antitumor plasma cytokine pattern (DCP/APCP) consisting of plasma IL-12, IL-6, and IL-4 concentration changes. This DCP/APCP composite measure identifies plasma IL-12 concentration increases, plasma IL-6 concentration decreases, and plasma IL-4 concentration increases correlated to relative tumor volume decreases caused by DCP dosing. The finding that the novel calcium pterins and CaCl 2·2H 2O treatments decrease plasma IL-6 concentrations corroborates the previous finding that CaPterin dosing decreases plasma IL-6 concentrations in this mouse/tumor system [Moheno, P., Pfleiderer, W., Dipasquale, A.G., Rheingold, A.L., Fuchs, D., 2008. Cytokine and IDO metabolite changes effected by calcium pterin during inhibition of MDA-MB-231 xenograph tumors in nude mice. Int. J. Pharm. 355, 238–248].

Effect of zinc supplementation on respiratory tract infections in children with cystic fibrosis

Zinc (Zn) has significant anti-oxidant and anti-inflammatory activity. Zn deficiency can occur in subsets of patients with cystic fibrosis (CF) especially those with malabsorption and impaired growth. Although supplemental Zn has significantly reduced infections in various disorders, its efficacy has not been thoroughly investigated in CF. We performed a double blind placebo controlled pilot study to investigate the effect of daily 30 mg elemental Zn for 1 year on the rate of respiratory tract infections (RTIs), use of antibiotics and plasma cytokines in 26 children with CF (ages 7-18 years). Plasma Zn, Cu, inflammatory cytokines and ex vivo generation of IL-2 were measured at baseline and at the end of the study. The number of days of oral antibiotics was lower in Zn treated patients compared to placebo (P = 0.05). However, compared to placebo, the effect of Zn was greater in patients who exhibited low plasma Zn at baseline (P = 0.02) than those who had plasma Zn levels identical to normal subjects (P = 0.55). Zn supplementation was marginally effective in reducing percentage increase in plasma IL-6 and IL-8 while increasing the percentage change in ex vivo generation of IL-2 in isolated mononuclear cell. In conclusion, oral intake of 30 mg/day of Zn reduced the number of days of oral antibiotics used to treat RTIs in children with CF. A higher daily Zn dose may be needed to decrease RTIs and modify immune responses.

Creatine supplementation reduces plasma levels of pro-inflammatory cytokines and PGE2 after a half-ironman competition

The effect of creatine supplementation upon plasma levels of pro-inflammatory cytokines: Interleukin (IL) 1 beta and IL-6, Tumor Necrosis Factor alpha (TNFalpha), and Interferon alpha (INF alpha) and Prostaglandin E(2) (PGE(2)) after a half-ironman competition were investigated. Eleven triathletes, each with at least three years experience of participation in this sport were randomly divided between the control and experimental groups. During 5 days prior to competition, the control group (n = 6) was supplemented with carbohydrate (20 g x d(-1)) whereas the experimental group (n = 5) received creatine (20 g x d(-1)) in a double-blind trial. Blood samples were collected 48 h before and 24 and 48 h after competition and were used for the measurement of cytokines and PGE(2). Forty-eight hours prior to competition there was no difference between groups in the plasma concentrations (pg x ml(-1), mean +/- SEM) of IL-6 (7.08 +/- 0.63), TNFalpha (76.50 +/- 5.60), INF alpha (18.32 +/- 1.20), IL-1 beta (23.42 +/- 5.52), and PGE(2) (39.71 +/- 3.8). Twenty-four and 48 h after competition plasma levels of TNFalpha, INF alpha, IL-1 beta and PGE(2) were significantly increased (P < 0.05) in both groups. However, the increases in these were markedly reduced following creatine supplementation. An increase in plasma IL-6 was observed only after 24 h and, in this case, there was no difference between the two groups. Creatine supplementation before a long distance triathlon competition may reduce the inflammatory response induced by this form of strenuous of exercise.

Hypercytokinemia and Hyperactivation of Phospho-p38 Mitogen-Activated Protein Kinase in Severe Human Influenza A Virus Infection

We postulate that hypercytokinemia plays a role in immunopathogenesis of severe human influenza. We prospectively studied 39 consecutive patients who were hospitalized with severe influenza A virus infection. On laboratory confirmation of the diagnosis, paired acute-phase (obtained at hospital admission) and convalescent-phase (obtained >10 days after hospital admission) plasma samples were collected for assay of 11 cytokines and chemokines (interleukin [IL] 1 beta; IL-6; IL-10; IL-12p70; tumor necrosis factor alpha; IL-8; monokine induced by interferon [IFN]-gamma; IFN-inducible protein 10; monocyte chemoattractant protein 1; regulated upon activation, normal T cell-expressed and secreted; and IFN-gamma) using cytometric bead-array analysis and enzyme-linked immunosorbent assay. Simultaneously, virus concentration in the acute-phase nasopharyngeal aspirate was determined using real-time quantitative reverse-transcriptase polymerase chain reaction. Intracellular signaling molecules regulating lymphocyte activation, phospho-p38 mitogen-activated protein kinase and phospho-extracellular signal-regulated protein kinase in CD4+ and CD8+ T lymphocytes were studied in the acute-phase samples using flow cytometric analysis and were compared with results for samples from healthy control subjects. Statistically significant increases in plasma IL-6 (3.7-fold increase), IL-8 (2.6-fold increase), IFN-induced protein 10 (4.9-fold increase), and monokine induced by IFN-gamma (2.3-fold increase) concentrations were detected during acute illness (P < .01 for all, by Wilcoxon signed-rank test); the highest concentrations were observed on symptom days 3 and 4. Corresponding plasma cytokine and chemokine concentrations and nasopharyngeal viral loads showed statistically significant correlations (rho = 0.41, 0.49, 0.54, and 0.46, respectively; P < or = .01). Phospho-p38 mitogen-activated protein kinase expression in CD4+ lymphocytes was increased, correlating with cytokine concentrations (e.g., for IFN-induced protein 10, rho = 0.78; P < .01); phospho-extracellular signal-regulated protein kinase was suppressed. Advanced age and comorbidity were associated with aberrant IL-6, IL-8, and monokine induced by IFN-gamma responses (P < .05, by Mann-Whitney U test). An elevated IL-6 concentration was independently associated with prolonged hospitalization (hospitalization for >5 days; P = .02), adjusted for age, comorbidity, and virus load. Hypercytokinemia (of proinflammatory and T helper 1 cytokines) is detected in severe influenza, correlating with clinical illness and virus concentration. Hyperactivation of phospho-p38 mitogen-activated protein kinase (in T helper cells) is possibly involved. Early viral suppression may attenuate these potentially deleterious cytokine responses.

Anti‐inflammatory effects of sevoflurane and mild hypothermia in endotoxemic rats

Volatile anesthetics and hypothermia attenuate the inflammatory response. We aimed to compare the anti-inflammatory effects of sevoflurane and mild hypothermia during experimental endotoxemia in the rat. Anesthetized, ventilated Sprague-Dawley (SD) rats were randomly treated as follows (n = 6 per group): lipopolysaccharide (LPS) only, animals received LPS [LPS 5 mg/kg, intravenously (i.v.)] with no further treatment. In the LPS-hypothermia group, rats were cooled down to a temperature of 33 degrees C 15 min after LPS-injection (LPS 5 mg/kg i.v.). In animals of the LPS-sevoflurane group, sevoflurane inhalation (1 MAC) was initiated 15 min after induction of endotoxemia. The LPS-sevoflurane-hypothermia group received combined sevoflurane and hypothermia 15 min after induction of endotoxemia. A Sham group served as control without endotoxemia or treatment. After 4 h of endotoxemia, plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and IL-10 were measured. Alveolar macrophages (AM) were ex vivo cultured for nitrite assay. Inhalation of sevoflurane significantly attenuated plasma levels of TNF-alpha (-60%, P < 0.05) and IL-1beta (-68%, P < 0.05) as compared with the LPS-only group. Hypothermia and its combination with sevoflurane significantly reduced TNF-alpha levels (-46% and -58%, each P < 0.05), but not IL-1beta. Application of mild hypothermia and also its combination with sevoflurane resulted in a significant increase in plasma IL-10 as compared with endotoxemic controls. Nitrite release from AM was found to be significantly suppressed by sevoflurane (-83%), hypothermia (-73%) and by the combination of both (-67%) (P < 0.05, each). Our data suggest that sevoflurane and mild hypothermia attenuate the inflammatory response during endotoxemia in vivo thus contributing to their beneficial role in clinical organ protection.

Cytokine and Oxidative Responses to Maximal Cycling Exercise in Sedentary Subjects

The simultaneous determination of the time course and magnitude of oxidative stress indicators and cytokine changes elicited by maximal incremental exercise has not yet been published for healthy sedentary subjects. The determination of normal exercise-induced changes in oxidant-antioxidant status and plasma cytokine represents a fundamental step before exploring patients suspected of altered biochemical responses. Fifteen healthy sedentary subjects performed an incremental cycle exercise until volitional exhaustion with measurement of maximal oxygen uptake (VO2max), two cytokines (IL-6 and TNF-alpha), and three indicators of oxidative stress (plasma thiobarbituric acid reactive substances (TBARS), reduced erythrocyte glutathione (GSH), and reduced plasma ascorbic acid (RAA)). At VO2max, we noted a significant increase in plasma IL-6 and TNF-alpha concentrations, concomitant with the decrease in plasma RAA level. Besides, the plasma TBARS increase and erythrocyte GSH decrease respectively occurred at the 5th and 10th minutes of recovery. The exercise-induced variations of all blood indicators were completed within the 20th minute of the recovery period. We found significant positive correlations between VO2max and the peak increases in IL-6 (but not TNF-alpha) and TBARS. The corresponding variations of IL-6 and TBARS were also correlated. This study indicates that blood samples for analyses of changes in both oxidant-antioxidant status and cytokine levels in response to maximal cycling exercise must be performed within the first 20 min of the postexercise recovery period.

GLUCOCORTICOIDS DO NOT PROTECT AGAINST THE LETHAL EFFECTS OF EXPERIMENTAL HEATSTROKE IN BABOONS

The mortality and neurological morbidity in heatstroke have been attributed to the host's inflammatory responses to heat stress, suggesting that anti-inflammatory therapy may improve outcome. We tested the hypothesis that a high dose of dexamethasone protects baboons against the lethal effects of heatstroke. Ten anesthetized baboons (Papio hamadryas) were assigned randomly to dexamethasone (n = 5) or control group (n = 5). Dexamethasone (2 mg/kg i.v.) was administered in four divided doses every 6 h starting immediately before heat stress and continuing during cooling. All animals were heat-stressed in a prewarmed neonatal incubator at 44 degrees C to 47 degrees C until systolic blood pressure fell less than 90 mmHg and then cooled passively at the ambient temperature. Mortality and neurological morbidity were noted, and biochemical markers of tissue injury/organ dysfunction were determined. Circulating interleukin (IL) 6 and complement components (C3 and C4) were measured sequentially. All heat-stressed animals had systemic inflammation indicated by increased plasma IL-6 and decreased C3 and C4 levels. Dexamethasone attenuated the complement system activation and maintained a higher plasma concentration of IL-6, with a significant augmentation of arterial blood pressure. Dexamethasone did not prevent the occurrence of severe heatstroke but unexpectedly aggravated significantly the tissue injury and multiorgan system dysfunction. Two animals (40%) in the control group and one in the steroid group survived (P > 0.05). Dexamethasone failed to protect the baboons from the lethal effects of heatstroke. These results do not support clinical testing of corticosteroids as beneficial in preventive or therapeutic strategies for the treatment of heatstroke in humans.

Role of TNF‐α in the dependency of Angiotensin II hypertension on IL‐6

Our laboratory has reported that chronic Angiotensin II (Ang II) infusion increases plasma concentration of IL-6, and that preventing the increase in IL-6, by using IL-6 KO mice, attenuates Ang II hypertension. The mechanism by which Ang II increases IL-6 has yet to be determined. However, the proinflammatory cytokine TNF-alpha is an important stimulus for IL-6 secretion. Therefore, this study aimed to determine the role of TNF-alpha in the dependency of Ang II hypertension on IL-6. Mice were divided randomly into 4 groups: WT, TNF-alpha KO, WT + ANG, and TNF-alpha KO + ANG, and were implanted with blood pressure biotelemetry devices and allowed to recover for 5–7 days. After the baseline period (4 days) the animals were placed on a 4% NaCl diet for a 4-day high-salt control period. The AngII animals then had Ang II (90 ng/min) 14-day minipumps implanted subcutaneously under brief isoflurane anesthesia. High salt diet alone did not change MAP in either group. Ang II increased mean arterial pressure similarly by ~30 mmHg over the 14-day infusion period in both the WT and KO groups. AngII infusion also increased plasma IL-6 in the TNF-KO mice from < 5 to 27+/− 8 pg/ml, thus suggesting that TNF was not required for the effect of AngII to stimulate IL-6 secretion. These results suggest that neither the IL-6 response nor the hypertensive response to chronic AngII-salt is dependent on TNF-alpha.

REBUTTAL FROM DR. MOONEY

REBUTTAL FROM DR. MOONEY

Microenvironment-Induced Endothelial Heterogeneity Stimulates Retinal Neovascularization in Sickle Mice.

Retinopathy is a serious complication of sickle cell disease (SCD) which is accompanied by endothelial activation and a pro-inflammatory microenvironment. We hypothesized that endogenous and exogenous factors modulate the endothelial microenvironment and endothelial specific alterations leading to retinal neovascularization. While VEGF receptor 2/Flk1 is a key player in the process of angiogenesis, opioids used to treat pain in SCD also promote angiogenesis. Therefore, we examined the role of opioids in the regulation of endothelial microenvironment, Flk1 expression and endothelial activity, using wild type (WT) and NY1DD sickle mice with transgenes for human α and βS globin. We injected 9–11 month old mice with morphine subcutaneously (50 mg/day/70 Kg with 10 mg increments every 2 weeks and/or equimolar amount of naloxone) for 10 to 16 months. NY1DD mouse retina exhibited appreciably higher expression of phospho-Flk1 vs WT which was further upregulated by morphine treatment for 10 and 16 months. Naloxone treatment antagonized morphine induced upregulation of phospho-Flk1, suggesting an opioid receptor mediated effect. Upregulation of phospho-Flk1 was accompanied by an increase in cell cycle regulatory protein cyclin D1 and stimulation of phospho-MAPK/ERK and phospho-Akt in morphine vs PBS treated mouse retina. Furthermore, morphine treatment led to a 5 and 20 fold increase in plasma IL6 and TNFα, respectively as compared to PBS treatment and promoted retinal neovascularization. Thus morphine treatment exaggerates the pro-inflammatory micro-environment and orchestrates a pro-angiogenic tone by upregulating Flk1 and activating the growth and survival promoting signaling in NY1DD mouse retina. To specifically delineate the role of opioids in endothelial activity leading to retinopathy, we isolated retinal endothelial cells (REC) from WT and NY1DD mice. Both VEGF and morphine stimulated REC proliferation in a dose-dependent fashion. Maximum proliferation was achieved with 1 μm morphine or 10 ng/ml VEGF in WT REC, but it was unsaturable upto 10 μm morphine or 1 μg/ml VEGF in NY1DD REC. Optimum morphine and VEGF-induced REC proliferation was 1.5 and 3 fold, respectively in NY1DD Vs WT REC, suggestive of a heterogeneity between WT and NY1DD REC. Saturation kinetics and opioid receptor binding studies showed that the Bmax for 3H-diprenorphine and the number of opioid receptor binding sites were 3-fold higher in NY1DD vs WT REC. RT-PCR analysis showed a higher expression of both Flk1 and μ opioid receptor (MOR) in NY1DD vs WT REC. Incubation of WT REC with IL6 as well as morphine for 48h upregulated Flk1 protein expression. Morphine-induced upregulation of Flk1 was abrogated by naloxone, anti-IL6 antibodies and STAT3 inhibitor Ac-PpYLKTK-OH. On the other hand, incubation of WT-REC with VEGF or IL6 for 48h upregulated MOR expression. Together, these data suggest that morphine stimulates Flk1 expression directly via opioid receptor(s) and also by upregulating IL6 via a STAT3 signaling pathway, while VEGF and IL6 also stimulate MOR expression. Therefore, a pro-inflammatory microenvironment in SCD upregulates endothelial Flk1 and opioid receptors, which is further exaggerated by addition of morphine leading to increased retinal neovascularization. It is likely that opioid use in SCD promotes retinopathy and that opioid receptor antagonists may play a preventive role.

Tissue compartment-specific role of estrogen receptor subtypes in immune cell cytokine production following trauma-hemorrhage

Although 17beta-estradiol administration following trauma-hemorrhage attenuates plasma cytokines and alteration in immune cell cytokine production, it is not known whether the salutary effects are mediated via estrogen receptor (ER)-alpha or ER-beta. Accordingly, we examined which ER subtype predominantly mediates the salutary effects of 17beta-estradiol on systemic inflammatory response/immune cell cytokine production in various tissues following trauma-hemorrhage. Male rats underwent trauma-hemorrhage (mean blood pressure: 40 mmHg for 90 min) and fluid resuscitation. The ER-alpha agonist propyl pyrazole triol (PPT; 5 microg/kg), the ER-beta agonist diarylpropionitrile (DPN; 5 microg/kg), 17beta-estradiol (50 microg/kg), or vehicle (10% DMSO) was injected subcutaneously during resuscitation, and various measurements were made 24 h thereafter. 17beta-Estradiol or PPT administration following trauma-hemorrhage prevented the increase in plasma IL-6 and IL-10 levels that were observed in vehicle-treated animals. IL-6 and TNF-alpha production by Kupffer cells increased; however, splenic macrophages (SMPhi), alveolar macrophages (AMPhi), and peripheral blood mononuclear cells (PBMC) had decreased release of these cytokines after trauma-hemorrhage. IL-10 production, however, increased in all macrophage populations. Administration of 17beta-estradiol following trauma-hemorrhage prevented all of these alterations. PPT had the same effects as 17beta-estradiol on IL-6 and TNF-alpha production by Kupffer cells and SMPhi, and DPN had the same effects on AMPhi and PBMC. The same effects as 17beta-estradiol on IL-10 production were observed by PPT on Kupffer cells and DPN on PBMC. Both agonists were equally effective on SMPhi and AMPhi. Thus ER subtypes have tissue compartment-specific roles in mediating the effects of 17beta-estradiol on immune cell functions following trauma-hemorrhage.

Pre-existing inflammatory state compromises heat tolerance in rats exposed to heat stress

This study investigated the roles of endotoxemia and heat-induced tissue damage in the pathology of heat stroke. In groups of eight, male Wistar rats were treated with heat exposure only (HE), or heat exposure with turpentine (T+HE), dexamethasone (D+HE), and turpentine and dexamethasone combined (TD+HE). The rats remained sedated for 2 h after receiving the respective treatments, followed by heat exposure until the core temperature (T(c)) was 42 degrees C for 15 min; control rats received turpentine (T), dexamethasone (D), and turpentine and dexamethasone (TD) without heat stress. Blood samples were collected before treatment (baseline I), after 2 h of passive rest (baseline II), at T(c) 40 degrees C (T40), and 15 min after achieving T(c) 42 degrees C (T42). No rats died in the nonheat-stressed groups. Survival rate was lowest in the TD+HE rats (37.5%), followed by the HE (62.5%), T+HE (75%), and D+HE (100%) rats (P < 0.05). The duration of survival at T42 degrees C was shortest in the TD+HE rats (9.9 +/- 6.2 min) (P < 0.01), followed by the T+HE (11.3 +/- 6.1 min) and the HE (12.2 +/- 4 min) (P < 0.05) rats. The increase in plasma IL-6 concentrations was highest in the T+HE (352%) and HE (178%) rats (P < 0.05). D+HE treatment suppressed the increases in plasma aspartate transaminase, alanine aminotransferase, and IL-6 and LPS concentrations during severe heat stress. Heat stroke can be triggered by endotoxemia or heat-induced tissue damage, and preexisting inflammation compromises heat tolerance, whereas blocking endotoxemia increases heat tolerance.

Cognitive dysfunction, brain-derived neurotrophic factor and IL-6 levels in cancer patients with depression

8632 Background: Increased proinflammatory cytokines (IL-6) and decreased brain-derived neurotrophic factor (BDNF) levels have been implicated in the pathophysiology of depression. Depression has been shown to be associated with cognitive dysfunction. The objective of this study was to assess the correlations between cognitive dysfunction, IL-6 and BDNF in cancer patients (pts) with depression. Methods: Depression was assessed in 55 patients with metastatic cancer by the Hospital Anxiety and Depression Scale (HADS) and diagnosis was established according to DSM-IV criteria. Cognitive function was assessed by the Auditory Verbal Learning Test (AVLT). Plasma concentrations of Interleukin-6 and BDNF were measured at 8 AM the same day. In the statistical analysis the Mann-Whitney test and the Pearson correlation were applied. Results: Pts characteristics (n=55): median age 60 y (25–85); 76.9% Females, 23.1% males. 52% of pts had depression. There were no significant differences in mean age or Karnofsky-index between pts with and without depression. Depression was associated with a significant higher median IL-6 level (14.8 vs. 3.7 pg/ml; p&lt;0,001). For Cognitive function only the longterm memory was significantly reduced in depression (p=0.01). However, there was no difference in BDNF levels between both groups (p=0.164). There were correlations between HADS-D score and IL6 (r=4.11; p=0.002), IL-6 and BDNF (r= −0.42; p=0.001), BDNF and longterm memory (r=0.48; p=0.02). No correlations were found for level of depression (HADS-D score) and BDNF levels (r= −0.20; P=0.14). Conclusions: Depression and increased plasma IL-6 concentrations are strongly associated in pts with cancer. There seems to be no association between BDNF and depression in cancer pts. However there is a positive correlation between the cognitive function, at least for longterm memory, with BDNF. No significant financial relationships to disclose.

Fucoidan prevents concanavalin A-induced liver injury through induction of endogenous IL-10 in mice

Fucoidan is a complex of sulfated polysaccharides derived from non-mammalian origin such as marine brown algae and induces cytokine expression. We investigated the effect of fucoidan on concanavalin A (Con A)-induced liver injury in mice. Liver injury was induced by an intravenous injection of Con A (18.5mg/kg). Various doses of fucoidan (1-30mg/kg) were intravenously administered 30min before Con A injection. The plasma alanine aminotransferase (ALT) and several cytokines levels were determined, and hepatic histological changes were also assessed. The effect of fucoidan administration by itself on induction of interleukin (IL)-10 in plasma and liver tissue was investigated. Con A administration induced an elevation of plasma ALT level, and fucoidan administration dose-dependently prevented the Con A-induced elevation of plasma ALT. Con A administration increased plasma TNF-alpha and IFN-gamma levels, and fucoidan pretreatment significantly inhibited these alterations and increased plasma IL-10 level. The inhibitory effect of fucoidan on Con A-induced liver injury and production of proinflammatory cytokines were reversed by anti-mouse IL-10 antibody pretreatment. Fucoidan induced the IL-10 production in plasma and liver tissue. These findings suggest that fucoidan prevents Con A-induced liver injury by mediating the endogenous IL-10 production and the inhibition of proinflammatory cytokine in mice.

Genetic and pharmacologic alteration of PI3K/Akt activity modulates LPS‐induced cytokine expression in vitro and in vivo .

Pharmacologic inhibition of phosphatidylinositol–3-kinase (PI3K) enhances LPS-induction of IL-6 gene expression in monocytes and inflammation in endotoxemic mice. Class IA PI3K is comprised of a 110kD catalytic subunit (α, β, or δ) and a 85kD regulatory subunit (p85α or p85β). PI3K activation of Akt is counterbalanced by the phosphatase PTEN. Loss of p85α (p85α−/−) results in reduced PI3K/Akt activity, whereas loss of PTEN (PTEN−/−) enhances Akt activity. In vitro, peritoneal macrophages (PMs) from p85α−/− mice produced significantly more IL-6 upon LPS stimulation compared to wild-type PMs, whereas LPS-induced IL-6 expression was reduced in PMs from PTEN−/− mice. In vivo, transplantation of bone marrow from p85α−/− mice into C57Bl/6 recipient mice increased plasma IL-6 concentration and reduced survival after LPS treatment compared to mice receiving bone marrow from wild-type mice. Next, we tested the hypothesis that insulin attenuates inflammation in endotoxemic mice, in part, by activation of PI3K. The PI3K inhibitor wortmannin reduced the protective effect of insulin in endotoxemic mice. In summary, our data support the hypothesis that PI3K activity in the monocyte/macrophage suppresses inflammation in endotoxemia. Furthermore, the data suggest that the anti-inflammatory action of insulin may be dependent on its ability to activate PI3K signaling pathways.