Increased Plasma TNF-alpha Research Articles

Possible Alterations in the Plasma Levels of Pro (TNF-alpha) and Anti-inflammatory (IL-10) Cytokines in Long-Term Insomnia

Long-term/chronic insomnia occurs in patients for over one month; it can affect the functions of the immune system and responses, which may involve cytokines. The aim was to determine alterations of Tumor necrosis factor alpha (TNF-alpha) and IL-10 cytokines in long-term insomnia. Thirty-three long-term/chronic insomnia patients (male, 22; female, 11) aged 47-61 years were initially recruited. Seven of them who were infected with microbial agents were excluded from the study. Of the 26 free of infectious agents only 21 (female, 5; male, 16) were successfully monitored. Age-matched apparently healthy non-insomnia subjects (male, 25; female, 25) free of the infectious agents were recruited as control. Plasma TNF-alpha, IL-10, HBsAg, anti-HCV, and HIVp24 antigen were assayed by ELISA method while determination of Mycobacterium tuberculosis was by Ziehl–Neelsen staining of sputum and Plasmodium spp. by thick blood Giemsa staining. Of the 33 insomnia patients initially recruited, 21.2% (7) were infected with microbial agents (Plasmodium spp., 6.1% (2); HCV, 3.0% (1); HBV, 6.1% (2); Mycobacterium tuberculosis, 3.0% (1); Plasmodium spp. + HBV, 3.0% (1); and HIVp24, 0). Twenty-one chronic insomnia patients were finally investigated on cytokines. There were significantly higher mean plasma values of TNF-alpha and IL-10 cytokines in chronic insomnia patients before treatment than the values obtained in the control subjects (p < 0.05). The results also showed a significantly lower mean plasma value of TNF-alpha cytokine in chronic insomnia patients after treatment than the values obtained in the patients before treatment. There were no significant differences in the mean plasma values of IL-10 cytokines in chronic insomnia patients before and after treatment (p > 0.05). There was a significant increase in plasma TNF-alpha and IL-10 cytokines in long-term insomnia patients before treatment while plasma TNF-alpha significantly decreased after treatment, and no significant difference was obtained in the plasma IL-10 before and after treatment. TNF-alpha could be a good investigative index of insomnia.

Epigenetic profile of women with breast cancer exhibiting a proinflammatory phenotype

We recently reported that women with breast cancer who experienced childhood adversity exhibit more intense and persistent elevations in behavioral symptoms and circulating proinflammatory cytokines from diagnosis through early survivorship. Here we evaluated histone post translational modifications (PTMs) associated with this proinflammatory phenotype. Women with breast cancer completed psychological and childhood adversity measures, and provided blood for isolation of peripheral blood mononuclear cells (PBMC) for immune and epigenetic analysis. We analyzed trajectories of outcomes, across diagnosis to 6-months post-cancer treatment, using hierarchical linear modeling. Findings revealed that greater exposure to childhood adversity was related to higher levels of perceived stress, depressive symptoms, fatigue and sleep disturbance; as well as, higher levels of circulating and PBMC produced IL-6 and TNF-alpha. Analysis of PTMs demonstrated intranuclear H3K9Ac associated with increased IL-6 production by CD14+, TNF-alpha by CD8+ and increased plasma TNF-alpha levels for CD56+ PBMC. H4K8Ac was associated with increased circulating and produced TNF-alpha for CD8 + PBMC. Further, exposure to neglect and abuse was related to histone modification, and these histone modifications were predictive of a greater proinflammatory response from cancer diagnosis through 6 months post-cancer treatment. In conclusion, women with breast cancer exposed to childhood adversity experience more behavioral symptoms and exhibit a proinflammatory phenotype, which related to histones H3K9Ac and H4K8Ac. Histone PTMs may underlie vulnerability for a proinflammatory phenotype in women with breast cancer.

The effects of arginine and nitric oxide synthase inhibitors on intestinal damage in guanylyl cyclase‐G gene knockout mice with intestinal ischemia and reperfusion

Previous study demonstrated that membrane‐bound guanylyl cyclase (mGC)‐G gene knockout (KO) mice with intestinal ischemia and reperfusion (II/R) had significantly alleviated jejunal damage and apoptosis compared to wild type (WT) mice. It is known that apoptosis is controlled by guanylyl cyclase‐generated cGMP and arginine‐derived nitric oxide (NO). Therefore, we investigated the roles of NO and mGC‐G gene in II/R‐induced intestinal damage. mGC‐G KO mice suffered with 45 min intestinal ischemia were intra‐peritoneally administered with arginine (300 mg/kg) or inhibitors of nitric oxide synthase (NOS), i.e., aminoguanidine (100 mg/kg) or L‐NAME (10 mg/kg), and were executed after 3 or 24 hours of reperfusion. KO mice had significantly decreased jejunal mass and villus height and increased plasma IL‐6 and mucosal nitrate/nitrite (NOx) and cGMP compared to WT mice. However, II/R‐induced jejuanl atrophy and systemic and local inflammatory responses were attenuated in KO mice as shown in the less increases in plasma NOx and mucosal TNF‐alpha (p<0.05). At 3 hr reperfusion, arginine significantly increased plasma IL‐6 and mucosa TNF‐alpha; AMG increased mucosal TNF‐alpha; and L‐NAME increased plasma TNF‐alpha and mucosal cGMP in KO mice. At 24 hr reperfusion, arginine, AMG, and L‐NAME decreased mucosal TNF‐alpha, plasma IL‐6, and muscularis width, respectively. In addition, AMG and L‐NAME further decreased plasma NOx at 3 and 24 hr reperfusion. However, mGC‐G KO‐and II/R‐induced jejunal atrophy was not significantly altered by arginine or NOS inhibitors. These results suggest that mGC‐G may play certain roles in affecting the effects of NO on jejunal histology and inflammatory response (NSC 96–2320‐B‐309–003‐MY2).

Early systemic inflammatory response in mice after a single oral gavage with live Escherichia coli is evidenced by increased TNF-alpha and nitric oxide production

Twenty-four female BALB/c mice were orally inoculated with 108 CFU Escherichia coli ATCC 25922 and euthanized 2.5, 7, 13 and 25h post-inoculation. The levels of organ nitric oxide (NO) and plasma endotoxin, TNF-alpha and nitrite/nitrate (NOx) were compared to those found in sham-inoculated mice, to evaluate systemic host-response to a low-level oral exposure to Gram-negative bacteria. Organ bacterial culture and immunohistochemistry for iNOS were performed on lungs, liver, kidneys and brain from all mice. Organ NO and plasma TNF-alpha levels were higher in E. coli-inoculated animals, but no differences were detected in plasma endotoxin levels, NOx or iNOS immunostaining for any of the animal groups. Single oral gavage with live E. coli stimulates an early systemic immune response in clinically healthy mice as evidenced by increased plasma TNF-alpha and organ NO levels, but bacteremia and endotoxemia are not related to this inflammatory response.

Resistance Training at Eight-Repetition Maximum Reduces the Inflammatory Milieu in Elderly Women

Inflammatory cytokines are associated with age- and inactivity-related diseases. We examined the influence of moderate- to high-intensity resistance trainings (RT) on inflammatory cytokines (interleukin 6 (IL-6) and 1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha)) in circulation and lipopolysaccharide (LPS)-stimulated whole blood in elderly women. Previously sedentary women (72 +/- 6.1 yr) were grouped according to their hormone replacement regimen: traditional estrogen/progesterone (HRT, n = 12), selective estrogen receptor modulator (SER, n = 7), no hormone replacement (NHR, n = 9), or nonexercise control group taking no hormone replacement (CON, n = 7). Participants in the HRT, SER, and NHR groups trained (three sets, 10 exercises at eight-repetition maximum (8RM)) 3 d x wk(-1), whereas participants in the CON group maintained their "normal" activity for 10 wk. Participants performed a bout of resistance exercise (RE at 8RM; HRT, SER, and NHR groups) or sat quietly (CON) before (BT) and after (AT) RT to assess the influence of training on the acute responses to RE. Blood samples were obtained preexercise (PR), postexercise (PO), and 2 h postexercise (2H; same time points for resting CON). Hormone status had no influence on dependent variables, so HRT, SER, and NHR groups were collapsed into one exercise group (EX, n = 28) and compared with CON. RT significantly reduced resting serum TNF-alpha level by 37%. RT also reduced LPS-stimulated production of IL-6, IL-1beta, and TNF-alpha at all time points (PR, PO, and 2H; per monocyte). Acute RE transiently increased plasma TNF-alpha, but blunted the circadian increase in LPS-stimulated inflammatory cytokines observed in CON. The blunting effect in EX was significantly greater AT compared with BT. RE also resulted in an increase in plasma IL-6, which was significantly reduced AT (BT: PR = 1.6 +/- 0.5, PO = 2.8 +/- 0.5; AT: PR = 1.8 +/- 0.3, PO = 2.4 +/- 0.3). We found that 10 wk of moderate- to high-intensity RT 1) reduced the systemic inflammatory milieu and 2) abrogated exercise-induced circulating IL-6 in previously sedentary elderly women.

Circulating Free Fatty Acids do not Contribute to the Acute Systemic Inflammatory Response. An Experimental Study in Porcine Endotoxaemia

Intensive insulin therapy, aiming for strict normoglycaemia, is associated with increased survival in critically ill patients. Insulin therapy concomitantly reduces plasma-free fatty acids. Recent studies indicate that free fatty acids mediate inflammation. In addition to plasma glucose and free fatty acid-lowering effects, insulin also has anti-inflammatory properties. This study was designed to study the pro-inflammatory effects of two free fatty acid concentrations during acute endotoxaemia and controlled comparable levels of plasma glucose and insulin. Twenty pigs were anaesthetized and mechanically ventilated. Pigs were randomized to two different, constant Intralipid infusion rates, throughout observation. All pigs were administered continuous intravenous infusion of endotoxin and subjected to controlled levels of p-glucose (4.5 mmol/l) and insulin by use of a hyperinsulinaemic euglycaemic clamp. Changes in circulating tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, leucocytes, insulin, glucose, free fatty acids, triglycerides, albumin, blood gases, temperature, and, haemodynamic function were monitored. Immediately following killing, biopsies were taken from heart and kidney. Biopsies were analysed for protein content of TNF-alpha, IL-6, IL-8 and IL-10. Sustained elevated and significantly different plasma levels of free fatty acids were demonstrated between groups (mean free fatty acid concentrations, 1.62 mM versus 0.58 mM, p < 0.0002). Endotoxaemia induced a steep increase in plasma TNF-alpha, IL-6 and leucocytes, however, without differences between the low- and high-free fatty acid groups. Cytokine content in heart and kidney tissue was not modified by free fatty acids. Compared with the response obtained at lower free fatty acid levels, high free fatty acid levels did not exacerbate the inflammatory response to acute endotoxaemia. Our results do not support the role of free fatty acids as a significant pro-inflammatory mediator.

Recombinant human growth hormone improves survival and protects against acute lung injury in murine Staphylococcus aureus sepsis

To investigate whether recombinant human growth hormone (rhGH) reduces mortality and protects against Staphylococcus aureus sepsis-induced acute lung injury. The bacteria-positive rate of blood smears and bacteria colony counts in bacteria plate culture, TNFalpha and IL-10 plasma levels, lung injury score, expression of intercellular adhesion molecule-1 (ICAM-1) as well as activation of nuclear factor-kappa B (NF-kappaB) in the lungs were determined 6, 12 and 24 h after 140 KM mice were injected with physiologic saline (i.p. group C, n = 20); S. aureus E311122 (1.75 x 10(12) cfu/L, 40 ml/kg, i.p. group S, n = 60); or S. aureus (as group S) with a subsequent treatment of rhGH (1.0 U kg(-1) day(-1)), i.m. group T, n = 60). The cumulative survival rate of an additional 15 mice from each group was followed for 7 days post S. aureus injection. rhGH treatment significantly increased IL-10 plasma levels and the 7-day cumulative survival rate, whereas the bacteria-positive rate of blood smears, bacteria colony counts in bacteria plate cultures, lung injury score, ICAM-1 and NF-kappaB expression in the lungs were significantly reduced. In addition, rhGH treatment significantly suppressed the S. aureus sepsis-induced elevation of TNFalpha plasma levels. These results indicate an ability of rhGH to prevent S. aureus sepsis-induced acute lung injury in mice, which may be attributed to attenuation of increased plasma TNFalpha levels, and elevated IL-10 plasma levels as well as reduced ICAM-1 expression and inhibited NF-kappaB activity in the lungs.

Systemic levels of tumor necrosis factor alpha during hemodialysis with cellulosic membranes: no effect of the sterilization procedure.

Extractable constituents of dialyzer membranes (e.g., monomers and beta-glucans) may induce the production of cytokines in vitro. We therefore studied circulating tumor necrosis factor alpha (TNF alpha) levels in 23 stable hemodialysis patients during treatment with dry Cuprophan membranes (ETO-sterilized n = 10, steam-sterilized n = 13) longitudinally over a period of 4 weeks. After 4 weeks, those 5 patients of each group showing the highest TNF alpha levels were switched to steam-sterilized, wet Cuprophan membranes. No significant increase in plasma TNF alpha was observed during hemodialysis with either ETO- or steam-sterilized dry Cuprophan membranes. A substantial TNF alpha increase (> or = 100% compared to pre-HD values), however, was observed during 14 of 84 treatment sessions. In 5 selected patients with ETO-sterilized, dry Cuprophan dialyzers, TNF alpha rose from (mean +/- SEM) 17.2 +/- 3.0 (pre-HD) to 20.9 +/- 6.2 (120 min) and 21.9 +/- 4.5 pg/ml (240 min). Corresponding levels in patients with steam-sterilized, dry Cuprophan were 16.2 +/- 5.4 (pre-HD), 21.9 +/- 6.8 (120 min), and 16.0 +/- 3.7 pg/ml (240 min), respectively. There was no difference between ETO- and steam-sterilized dialyzers. No significant reduction in mean TNF alpha plasma levels or in frequency of elevated peak levels was achieved when these patients were switched to wet Cuprophan dialyzers for another 4 weeks. It is suggested that an induction of elevated TNF alpha levels during hemodialysis is possible but is not observed regularly during treatment with Cuprophan membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokine blockade attenuates sympathoexcitation in heart failure: Cross‐talk between nNOS, AT‐1R and cytokines in the hypothalamic paraventricular nucleus

To investigate evidence for the interplay between cytokines, angiotensin II and nNOS in the paraventricular nucleus (PVN), for regulating sympathetic outflow in a rat model of CHF. Heart failure was induced in Sprague-Dawley rats by coronary artery ligation. One group of rats was treated with pentoxifylline (PTX, 30 mg/kg IP), a cytokine blocker, or vehicle, for 5 weeks. Another group of rats was pre-treated with PTX before coronary ligation to study prior cytokine blocking effect on survival. Both groups were combined in the analysis. Echocardiography demonstrated an increase in LV end-diastolic pressure and Tei index after 5 weeks in CHF rats. ELISA revealed a significant increase in plasma TNF-alpha and IL-1beta in CHF rats. Inducible NOS (iNOS) and angiotensin receptor-type 1 (AT-1R) mRNA expressions were increased, while neuronal NOS (nNOS) was decreased in the PVN of CHF rats; these changes were reversed by PTX. PTX treatment also decreased plasma norepinephrine and epinephrine levels and improved baroreflex control of renal sympathoexcitation in CHF rats. Immunohistochemistry revealed elevated 3-nitrotyrosine formation in the heart and the PVN of CHF rats, but not in PTX treated rats. PTX decreased both peripheral and central cytokine expression, alleviated nitric oxide dysregulation, and inhibited the formation of peroxynitrite in the PVN resulting in decreased sympathoexcitation in CHF rats.

Soluble IL-2 receptor and tumour necrosis factor-α in plasma of haemophilia patients infected with HIV

We measured plasma concentrations of soluble receptors for IL-2 (sIL-2R) and tumour necrosis factor-alpha (TNF-alpha) in 149 haemophilia patients. Soluble IL-2R levels were elevated in 37% of 62 HIV-seronegative patients (mean 570 +/- 27 U/ml versus 361 +/- 17 U/ml in the control group, P less than 0.0001), in 78% of 68 HIV-seropositive patients (928 +/- 49 U/ml, P less than 0.0001), and in 95% of 19 AIDS/ARC patients (1578 +/- 199 U/ml, P less than 0.0001 compared with controls and with HIV-seronegative patients; P less than 0.005 compared with HIV-seropositive asymptomatic patients). A negative correlation was observed between sIL-2R, relative and absolute numbers of CD4+ cells (P less than 0.0001), and CD4/CD8 ratios (P less than 0.0001). There was also a negative correlation between sIL-2R in plasma and the cellular expression of IL-2R (P less than 0.001). We found a significant association of sIL-2R and plasma neopterin (P less than 0.0001). With progression of the disease from HIV-seronegative to seropositive without symptoms and to full manifestation of AIDS/ARC, sIL-2R plasma levels increased. The highest levels were found at the time of diagnosis of AIDS/ARC, but the levels decreased again during the following 18 months. Eight per cent of HIV-seronegative patients, 32% of HIV-seropositive patients, and 24% of patients with AIDS/ARC had increased plasma TNF-alpha. We conclude that sIL-2R and TNF-alpha plasma levels are elevated in HIV-infected haemophilia patients and that sIL-2R is a marker for disease progression from asymptomatic HIV-seropositive to AIDS/ARC.

Induction of tumour necrosis factor-alpha during haemodialysis. Influence of the membrane type

Some of the secondary clinical effects induced by long-term haemodialysis in patients with end-stage renal failure have been related to an increased production of interleukin-1 (IL-1). We investigated the role of another cytokine which shares a number of biological properties with IL-1, tumour necrosis factor-alpha (TNF-alpha). In long-term haemodialysed patients, we found at the beginning of the dialysis increased plasma TNF-alpha levels and enhanced monocyte capacity to produce TNF-alpha spontaneously ex vivo. Non-haemodialysed uraemic patients also presented increased plasma TNF-alpha levels. During dialysis with cellulose acetate (CA) or polysulphone (PS) membranes, plasma TNF-alpha levels and the spontaneous and lipopolysaccharide-induced production of TNF-alpha by monocytes remained at predialysis levels. In contrast, when cuprophane membranes were used, there was a significant increase in plasma TNF-alpha levels and in both spontaneous (10-fold) and lipopolysaccharide-induced (seven-fold) ex vivo TNF-alpha production by monocytes. These results suggest that monocytes are stimulated during haemodialysis with the poorly biocompatible cuprophane membrane.

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.

Nitric oxide‐releasing flurbiprofen reduces formation of proinflammatory hydrogen sulfide in lipopolysaccharide‐treated rat

The biosynthesis of both nitric oxide (NO) and hydrogen sulfide (H2S) is increased in lipopolysaccharide (LPS)-injected mice and rats but their interaction in these models is not known. In this study we examined the effect of the NO donor, nitroflurbiprofen (and the parent molecule flurbiprofen) on NO and H2S metabolism in tissues from LPS-pretreated rats. Administration of LPS (10 mg kg(-1), i.p.; 6 h) resulted in an increase (P<0.05) in plasma TNF-alpha, IL-1beta and nitrate/nitrite (NO(x)) concentrations, liver H2S synthesis (from added cysteine), CSE mRNA, inducible nitric oxide synthase (iNOS), myeloperoxidase (MPO) activity (marker for neutrophil infiltration) and nuclear factor-kappa B (NF-kappaB) activation. Nitroflurbiprofen (3-30 mg kg(-1), i.p.) administration resulted in a dose-dependent inhibition of the LPS-mediated increase in plasma TNF-alpha, IL-1beta and NO(x) concentration, liver H2S synthesis (55.00+/-0.95 nmole mg protein(-1), c.f. 62.38+/-0.47 nmole mg protein(-1), n = 5, P<0.05), CSE mRNA, iNOS, MPO activity and NF-kappaB activation. Flurbiprofen (21 mg kg(-1), i.p.) was without effect. These results show for the first time that nitroflurbiprofen downregulates the biosynthesis of proinflammatory H2S and suggest that such an effect may contribute to the augmented anti-inflammatory activity of this compound. These data also highlight the existence of 'crosstalk' between NO and H2S in this model of endotoxic shock.

Alcohol increases tumor necrosis factor α and decreases nuclear factor‐κb to activate hepatic apoptosis in genetically obese mice†

Both obesity and alcohol can cause oxidative stress, cytokine induction, and steatohepatitis. To determine the consequences of their combination, we compared the hepatic effects of moderate ethanol binges in lean and obese ob/ob mice. Mice received water or ethanol (2.5 g/kg) by gastric intubation daily for 4 days, and were killed 2 hours after the last administration. Some obese mice also received pentoxifylline, an inhibitor of tumor necrosis factor-alpha (TNF-alpha) production, before each ethanol administration. In lean mice, these moderate ethanol doses did not increase plasma TNF-alpha and hepatic caspase-3 activity, but triggered some apoptotic hepatocytes. Naive ob/ob mice had a few necrotic and apoptotic hepatocytes, but exhibited little oxidative stress, possibly because of adaptive increases in manganese superoxide dismutase, heat shock protein 70 (Hsp70), mitochondrial cytochrome c, and mitochondrial DNA. Alcohol administration to ob/ob mice did not increase oxidative stress despite increased CYP2E1, but increased plasma TNF-alpha, further increased Hsp70, and profoundly decreased p65 nuclear factor kappaB (NF-kappaB) protein and DNA-binding activity in nuclear extracts. Caspase-3 was activated, and more apoptotic hepatocytes were found in intoxicated obese mice than naive obese mice. In intoxicated obese mice, pentoxifylline fully prevented the increase in plasma TNF-alpha the decrease in nuclear NF-kappaB activity, and the increase in hepatic caspase-3, and it also decreased hepatic triglycerides. In conclusion, obese mice develop adaptations that may limit oxidative stress. Moderate ethanol intoxication does not increase oxidative stress in obese mice, but increases TNF-alpha and also decreases nuclear NF-kappaB activity, thus unleashing the apoptotic effects of TNF-alpha.

Depleted skeletal muscle mitochondrial DNA, hyperlactatemia, and decreased oxidative capacity in HIV‐infected patients on highly active antiretroviral therapy

The nucleoside reverse transcriptase inhibitors (NRTIs), especially stavudine, may deplete mitochondrial (mt) DNA in human tissues by inhibiting the mitochondrial polymerase gamma, a setting, which is associated with hyperlactatemia. The aim of the present study was to examine whether hyperlactatemia is associated with depletion of skeletal muscle (sm)-mtDNA and decreased oxidative capacity in HIV-infected patients on NRTI based highly active antiretroviral therapy (HAART) and whether HIV infection itself is associated with sm-mtDNA depletion. Sm-mtDNA was determined in 42 HIV-infected patients (35 patients on HAART including at least one NRTI (HIV-NRTI) and 7 patients never treated with antiretroviral drugs (NAIVE)) and 14 healthy controls. Whole body oxidative capacity (DeltaGOX) was estimated in HIV-infected patients by indirect calorimetry. Hyperlactatemia (>or=2.0 mM) was detected in six HIV-NRTI, who all used Stavudine (P < 0.01), displayed depleted sm-mtDNA (P < 0.02) and decreased DeltaGOX (P < 0.01) compared with normolactatemic HIV-NRTI (n = 29). NAIVE displayed decreased sm-mtDNA (P < 0.05), increased HIV-RNA (P < 0.01) and increased plasma TNF-alpha (P < 0.05) compared to all HIV-NRTI (n = 35), in turn displaying decreased sm-mtDNA (P < 0.01) compared to healthy controls. Thus, hyperlactatemia in HIV-NRTI may be associated with pronounced depletion of sm-mtDNA, decreased oxidative capacity and current stavudine therapy. Further, HIV may deplete sm-mtDNA of NAIVE, which in part could be mediated through an enhanced pro-inflammatory response.

Increased tumour necrosis factor-alpha plasma levels during moderate-intensity exercise in COPD patients.

Post-training downregulation of muscle tumour necrosis factor (TNF)-alpha messenger ribonucleic acid (mRNA) expression and decrease in cellular TNF-alpha levels have been reported in the elderly. It is hypothesised that chronic obstructive pulmonary disease (COPD) patients may not show these adaptations due to their reduced ability to increase muscle antioxidant capacity with training. Eleven COPD patients (forced expiratory volume in one second 40 +/- 4.4% of the predicted value) and six age-matched controls were studied. Pre- and post-training levels of TNF-alpha, soluble TNF receptors (sTNFRs: sTNFR55 and sTNFR75) and interleukin (IL)-6 in plasma at rest and during exercise and vastus lateralis TNF-alpha mRNA were examined. Moderate-intensity constant-work-rate exercise (11 min at 40% of pretraining peak work-rate) increased pretraining plasma TNF-alpha levels in COPD patients (from 17 +/- 3.2 to 23 +/- 2.7 pg x mL(-1); p<0.005) but not in controls (from 19 +/- 4.6 to 19 +/- 3.2 pg x mL(-1)). No changes were observed in sTNFRs or IL-6 levels. After 8 weeks' endurance training, moderate-intensity exercise increased plasma TNF-alpha levels similarly to pretraining (from 16 +/- 3 to 21 +/- 4 pg x mL(-1); p<0.01). Pretraining muscle TNF-alpha mRNA expression was significantly higher in COPD patients than in controls (29.3 +/- 13.9 versus 5.0 +/- 1.5 TNF-alpha/18S ribonucleic acid, respectively), but no changes were observed after exercise or training. It is concluded that moderate-intensity exercise abnormally increases plasma tumour necrosis factor-alpha levels in chronic obstructive pulmonary disease patients without exercise-induced upregulation of the tumour necrosis factor-alpha gene in skeletal muscle.

The role of Kupffer cells and TNF-alpha in monocrotaline and bacterial lipopolysaccharide-induced liver injury.

Coexposure to small, noninjurious doses of the pyrrolizidine alkaloid phytotoxin monocrotaline (MCT) and bacterial lipopolysaccharide (LPS) results in synergistic hepatotoxicity. Both centrilobular and midzonal liver lesions occur and are similar to those seen from large, toxic doses of MCT and LPS, respectively. The nature of the lesions in vivo and results from studies in vitro suggest that injury is mediated indirectly rather than from a simple interaction of MCT and LPS with hepatic parenchymal cells. Accordingly, the role of inflammatory factors, such as Kupffer cells and TNF-alpha, in the development of MCT/LPS-induced liver injury was investigated. In Sprague-Dawley rats, MCT (100 mg/kg, i.p.) was administered 4 h before LPS (7.4 x 10(6) EU/kg, i.v.). Pretreatment of these animals with gadolinium chloride, an inhibitor of Kupffer cell function, attenuated liver injury 18 h after MCT administration. An increase in plasma TNF-alpha preceded the onset of hepatic parenchymal cell injury, raising the possibility that this inflammatory cytokine contributes to toxicity. Either pentoxifylline, an inhibitor of cellular TNF-alpha synthesis, or anti-TNF-alpha serum coadministered to MCT/LPS-treated animals significantly attenuated liver injury. These results suggest that Kupffer cells and TNF-alpha are important mediators in the synergistic hepatotoxicity resulting from MCT and LPS coexposure.

Hypercholesterolemia alters endotoxin-induced endothelial cell adhesion molecule expression.

While there is a growing body of evidence suggesting that hypercholesterolemia prior to the onset of atherosclerosis renders tissues more susceptible to inflammation, the mechanisms that underlie this exaggerated inflammatory response remain poorly defined. The overall objective of this study was to assess the influence of hypercholesterolemia on endotoxin-induced endothelial cell adhesion molecule (CAM) expression in different vascular beds. Another objective was to determine whether the altered endothelial CAM expression in hypercholesterolemic animals is associated with a corresponding change in plasma cytokine levels. Male Sprague/Dawley rats (SD) were placed either on a normal (control) or high cholesterol (HC) diet for 3 weeks. The dual radiolabeled monoclonal antibody (mAb) technique was used to measure the expression of P-selectin, E-selectin, ICAM-1, and VCAM-1 in different vascular beds after intraperitoneal injection of endotoxin (LPS) derived from Salmonella abortus equi. LPS induced a significant increase in the expression of all endothelial CAMs in both normocholesterolemic and hypercholesterolemic groups. However, hypercholesterolemia enhanced LPS-induced expression of P-selectin, E-selectin, and ICAM-1 in several vascular beds, while VCAM-1 expression was unaffected. Thrombocytopenia, induced with anti-platelet serum, did not alter LPS-induced P-selectin expression in either group, suggesting that platelets do not contribute to this response. Hypercholesterolemia was associated with an exaggerated increase in plasma TNF-alpha, but not IL-1beta, after LPS treatment. These results indicate that hypercholesterolemia in rats may render tissues more vulnerable to the inflammatory effects of LPS by enhancing the expression of certain endothelial CAMs.

Apoptosis and Dysregulated Ceramide Metabolism in a Murine Model of Alcohol‐Enhanced Lipopolysaccharide Hepatotoxicity

The role of apoptosis in EtOH-induced liver injury has not been investigated much. Therefore, the question whether apoptosis is a contributory factor to alcoholic liver disease remains to be answered. The purpose of this study was to characterize the liver apoptotic response in a murine model of alcohol-enhanced lipopolysaccharide (LPS) hepatotoxicity. Mice were fed an alcohol-containing liquid diet for 49 days followed by an acute LPS challenge. The liver state was judged on the basis of histological appearance, plasma liver enzyme activity (alanine:2-oxoglutarate and aspartate:2-oxoglutarate aminotransferases, as markers of hepatocytolysis), and plasma hyaluronan levels (as a marker of the sinusoidal endothelial cell scavenging function). The liver apoptotic response was assessed by DNA fragmentation (TUNEL procedure), and caspases-3 and -8 activity. To determine if ceramide played a role in the liver apoptotic response, the activity of acidic sphingomyelinase and tissue content of ceramide were also quantified. Alcohol exposure induced fat accumulation and sensitized the liver to LPS injurious effects. Plasma liver enzyme activity was elevated by alcohol and this effect was potentiated by LPS. Liver apoptosis was augmented by both alcohol and LPS treatment as reflected by high frequency of positive TUNEL staining nuclei and by an increased activity of caspase-3 and -8. Acidic sphingomyelinase activity was also increased and it was associated with an elevated tissue content of ceramide. In addition, LPS also increased plasma TNF-alpha levels. These changes were accompanied by elevated plasma hyaluronan, reflecting an impaired sinusoidal endothelial cell scavenging function. These results provide a more complete description of the liver apoptotic response to both alcohol and LPS and may constitute the basis for further mechanistic studies on a possible role apoptosis may play in alcoholic liver injury.

Plasma concentrations of tumor necrosis factor-alpha (TNF-alpha) and soluble TNF receptors in patients with bulimia nervosa.

Tumor necrosis factor-alpha (TNF-alpha) is a cytokine with numerous immunological and metabolic activities. In addition, TNF-alpha can stimulate a variety of physiological, neuroendocrine and behavioural responses of the central nervous system. In experimental animals, TNF-alpha induces changes in physiological and behavioural parameters which have also been observed in eating disorders. The biological activities of TNF-alpha are mediated by two structurally related, but functionally distinct receptors, TNF-RI and TNF-RII. Since injection of TNF-alpha results in increased shedding of TNF-alpha receptors, it is likely that TNF-alpha release is reflected by soluble TNF-receptors (sTNF-Rs) levels. We studied plasma concentrations of TNF-alpha and two sTNF-Rs (sTNF-RI and sTNF-RII) in female patients with bulimia nervosa. Twenty female patients with bulimia nervosa (BN) and 20 age-matched normal women (N) were studied. Plasma TNF-alpha concentrations were measured by enzyme immunoassay kit and plasma concentrations of sTNF-RI and sTNF-RII were measured by enzyme-linked immunosorbent assay. Plasma TNF-alpha concentrations in BN were significantly higher than those in N (4.7+/- 0.5 ng/l vs. 1.6+/-0.1 ng/l; P<0.01). Although no significant difference was observed in plasma sTNF-RI concentrations between the two groups, plasma sTNF-RII concentrations in BN were significantly higher than those in N (2080.0+/-107.5 ng/l vs. 1569.5 +/-84.0 ng/l; P<0.01). Plasma TNF-alpha concentrations were significantly related to plasma sTNF-RI concentrations (r = 0.511, P<0.05) and to plasma sTNF-RII concentrations (r = 0.532, P<0.05) in bulimic patients. However, plasma TNF-alpha concentrations were not related to body fat mass or to bulimic behaviours in these patients. Our present findings suggest that the adipose tissue may not be the immediate source of TNF-alpha in bulimic patients but the increase in plasma TNF-alpha in these patients may be derived from the central nervous system sources. The elevated sTNF-RII may reflect different shedding kinetics compared with sTNF-RI in bulimic patients.