Activation of Tumor Necrosis Factor-α System in Chronic Hepatitis C Virus Infection

Tumor necrosis factor- (TNF-)plays a central role in the host's immunomodulatoryresponse to infective agents. To evaluate theTNF- system in patients with chronic hepatitis Cvirus (HCV) infection, plasma, serum, and peripheral bloodmononuclear cells (PBMC) were prospectively collectedfrom 53 patients and 33 healthy control subjects.Circulating TNF- and TNF receptors were assayed by their respective enzyme immunoassays. Inaddition, TNF- mRNA was quantitated in PBMC usinga branched DNA assay, and production of TNF- byPBMC with and without lipopolysaccharide was also assessed. Patients with chronic HCV infectionhad a higher level of circulating TNF- comparedto healthy control subjects (9.62 ± 6.01 vs 3.66± 1.23 pg/ml, P < 0.001). They also had highercirculating levels of TNF receptors compared to control(CD120a: 3323 ± 1267, pg/ml, N = 49 vs 1855± 422 pg/ml, N = 33, P < 0.001; CD120b: 1290± 650 pg/ml, N = 51, vs 863 ± 207 pg/ml,N = 33, P < 0.001). Plasma TNF- level correlated with circulatingCD120a (r = 0.52, N = 49, P < 0.001) and weakly withCD120b (r = 0.32, N = 51, P = 0.02). Plasma TNF-also correlated with markers of hepatocellular injury, including ALT (r = 0.34, N = 53, P = 0.01) and-GST (r = 0.31, N = 43, P = 0.042), but not withserum HCV RNA levels. There was no difference in theTNF- mRNA levels in PBMC between patients with chronic HCV infection (1.4 ± 1.9units/106 cells, N = 8) and healthy control subjects(2.1 ± 1.4 units/106 cells, N = 8, P = NS). Therewas also no difference in the spontaneous production ofTNF- by PBMC (1 × 10⁶ cells/ml)between patients with chronic HCV infection (14.2± 36.5 pg/ml, N = 11) and healthy subjects (11.9± 14.0 pg/ml, N = 14, P = NS). However, patientswith chronic HCV infection produced more TNF- upon stimulation withlipopolysaccharide compared to healthy control subjects(1278 ± 693 pg/ml, N = 11, vs 629 ± 689pg/ml, N = 14, P < 0.05). These data indicate thatthe TNF- system is activated in patients with chronicHCV infection.     

Association of Tumor Necrosis Factor-α and Neutrophilic Inflammation in Severe Asthma

BackgroundThere is evidence that neutrophils are increased in the airway of severe disease or acute exacerbations of asthma. The mechanisms by which neutrophils are recruited to the airways and contribute to the pathophysiology of asthma remain to be elucidated. Tumor necrosis factor (TNF-α), which can induce both tissue accumulation and activation of neutrophils and eosinophils, has been shown to be increased in the airways of severe asthma. The objective of this study is to evaluate whether TNF-α is associated with neutrophilic inflammation in asthma.MethodsFollowing an inhalation of hypertonic saline, induced sputum was obtained from 9 healthy controls, 9 mild persistent asthma patients who were treated with low-dose inhaled corticosteroids; and 7 severe persistent asthma patients who were treated with combinations of drugs including high-dose inhaled corticosteroids, oral prednisolone, bronchodilators, and leukotriene receptor antagonist. After 0.1% dithiothreitol (DTT) homog- enization, they were examined for total cell count, cellular differentiation, and the concentrations of TNF-α and myeloperoxidase (MPO).ResultsThe concentration of TNF-α was not correlated with neutrophils in healthy controls or mild asthma patients. In sputum from severe asthma patients, however, the concentration of TNF-α is significantly correlated with both the percentage of neutrophils and the concentration of MPO. The concentration of TNF-α is not correlated with the percentage of eosinophils in healthy controls, mild asthma patients, or severe asthma patients.ConclusionsTNF-α may be a contributing molecule for both accumulation and activation of neutrophils in the airways of severe asthma.     

Tumor Necrosis Factor-α and Interleukin-1- β Polymorphisms in Pre-Eclampsia

Background: Pre-eclampsia is the most common critical condition during pregnancy. Plasma concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin-1-beta (IL-1β) increase in pregnant women with pre-eclampsia, compared to normal pregnant women. Objective: To investigate the polymorphisms of IL-1β (C+3954T), TNF-α (G- 308A), and (G-238A) in preeclemptic women northeastern Iran. Methods: This study was conducted on 153 preeclamptic women (case group) and 150 healthy pregnant women (control group), admitted to Ghaem and Imam Reza hospitals of Mashhad, Iran. IL-1β (C+3954T), TNF- α (G-238A) and TNF-α (G-308A) gene polymorphisms in the promoter region were screened by polymerase chain reaction. Data were analyzed, using SPSS version 16.0. Results: The mean age of the participants in the case and control groups was 28.2 ± 6.1 and 27.1 ± 6.3 years, respectively (P=0.68). The frequency of G-308A polymorphism was significantly higher in the case group, compared to the control group (p<0.001). However, no significant relationship was found between IL-1β genotype and pre-eclampsia (p=0.39). The frequency of TNF- α (G-238A) AA genotype was significantly higher in the case group, while GG genotype was less frequently detected in the case group, compared to the control group (p<0.001 for both genotypes). Moreover, the frequencies of AA genotypes of -238 TNF-α and G- 308A polymorphisms were significantly higher in the case group, compared to the control group (p<0.001). Conclusion: The significant correlation between inflammation promoting genotypes of TNF-α and Pre-eclampsia is noteworthy and provides evidence on the contribution of immune related genes in this disease.     

The Role of Tumor Necrosis Factor-α Receptors in Atherosclerosis

Tumor necrosis factor (TNF-α)-α is a cytokine exhibiting a plethora of activities involved in inflammation, immune regulation, and energy metabolism. TNF is produced by many cell types, including cells found in atherosclerotic lesions, such as activated monocytes or macrophages, T and B lymphocytes, mast cells, and smooth muscle cells. Two receptors mediate the functions of TNF, and both receptors are also present on cells of the artery wall and on cells involved in lesion development. Mice genetically engineered to lack expression of TNF and each of its receptors are now available and are being used to dissect the role of these molecules in protection from or development of atherosclerosis. The role of TNF receptors in atherosclerosis is the primary focus of this review.     

Tumor Necrosis Factor-α in Heart Failure: an Updated Review

Purpose of the Review

Proinflammatory cytokines are consistently elevated in congestive heart failure. In the current review, we provide an overview on the current understanding of how tumor necrosis factor-α (TNFα), a key proinflammatory cytokine, potentiates heart failure by overwhelming the anti-inflammatory responses disrupting the homeostasis.

Recent Findings

Studies have shown co-relationship between severity of heart failure and levels of the proinflammatory cytokine TNFα and one of its secondary mediators interleukin-6 (IL-6), suggesting their potential as biomarkers. Recent efforts have focused on understanding the mechanisms of how proinflammatory cytokines contribute towards cardiac dysfunction and failure. In addition, how unchecked proinflammatory cytokines and their cross-talk with sympathetic system overrides the anti-inflammatory response underlying failure.

Summary

The review offers insights on how TNFα and IL-6 contribute to cardiac dysfunction and failure. Furthermore, this provides a forum to begin the discussion on the cross-talk between sympathetic drive and proinflammatory cytokines and its determinant role in deleterious outcomes.

     

Biliary Interleukin-6 and Tumor Necrosis Factor-α in Patients Undergoing Endoscopic Retrograde Cholangiopancreatography

Cytokines are low-molecular-weight proteinmediators that possess a wide spectrum of inflammatory,metabolic, and immunomodulatory properties. Cytokineshave been shown to be produced by monocytes/macrophages, lymphocytes, fibroblasts, endothelial cells,and more recently, hepatocytes and biliary epithelium.The aim of this study was to define biliary levels ofinterleukin-6 (IL-6) and tumor necrosis factor- (TNF-) in patients undergoing endoscopicretrograde cholangiopancreatography (ERCP) in variousdisease states. Fifty-four patients undergoing ERCPcomprised the study group. IL-6 and TNF- were measured in aspirated bile using an ELISAtechnique. Levels of both TNF- and IL-6 weresignificantly higher in patients with cholangitis (P< 0.00001). Moreover, IL-6 was 100% specific forcholangitis since none of the patients without bacterialcholangitis — including patients with biliaryobstruction secondary to cholangiocarcinoma orpancreatic carcinoma — had measurable IL-6 intheir bile. Low levels of biliary TNF- were detectable in fivepatients without cholangitis; the sensitivity andspecificity of TNF- for cholangitis were 100% and82%, respectively. There was a strong statisticalcorrelation between biliary IL-6 and TNF- levels (r= 0.819, P < 0.0001). In contrast, the correlationsbetween biliary cytokines and serum biochemicalparameters were weak. These results suggest that IL-6and TNF- are sensitive markers for cholangitis and maydifferentiate it from other types of biliary tractdisease.     

Time Dependent Release of Interleukin-8 and Tumor Necrosis Factor-α in Platelet Concentrate

Contaminating white blood cells in stored platelet concentrate (PC) are the source of many pro-inflammatory cytokines. These are implicated in transfusion reactions. To study the release of interleukin (IL)-8 and tumor necrosis factor alpha (TNF-α) at different time interval in PC prepared by-platelet rich plasma (PRP) and buffy coat (BC) using different principles. Fifteen PCs were prepared by both the methods. The supernatants of PCs prepared by PRP and BC methods were collected aseptically after 1, 18, 65 and 112 h of preparation. pH, platelet and WBC counts were done. The supernatants were frozen in aliquots at −56 °C for measurement of IL-8 and TNF-α concentration using ELISA. The Mean ± SD value of WBC in PRP-PC was 7.4 ± 3.75 × 10⁷ and in BC-PC 3.9 ± 2.2 × 10⁷. The mean platelet counts were 6.05 ± 1.94 × 10¹⁰ and 6.54 ± 2.18 × 10¹⁰ respectively. The highest level of IL-8 in one hour was up to 30 pg/ml in both the type of PC. It increased up to 986 pg/ml in PRP-PC and 481 pg/ml in BC-PC at 112 h. IL-8 increased significantly during storage period of 5 days in both types of PCs (P0.000 and P0.01). TNF-α level remained low up to 18 h. The highest level was 72 pg/ml in PRP-PC and 57 pg/ml in BC-PC at 65 h. IL-8 levels significantly increased after one hour of storage and TNF-α. levels were low up to 18 h and then showed increase. The BC-PC had significantly low levels of IL-8 compared to PRP-PC (P0.0001).     

The Role of Tumor Necrosis Factor-α and Interferon-γ in Regulating Angiomotin-Like Protein 1 Expression in Lung Microvascular Endothelial Cells

BackgroundAngiogenesis in the alveolar septa is thought be a critical factor in pulmonary emphysema. Angiomotin-like protein 1 (AmotL1) is involved in angiogenesis via regulating endothelial cell function. However, the role of AmotL1 in the pathogenesis of pulmonary emphysema has not been elucidated. The objective of this study is to evaluate the expression of AmotL1 in lung tissues from a murine model with emphysema, as well as from patients with chronic obstructive pulmonary disease (COPD). Furthermore, we analyzed the regulation of AmotL1 expression by TNF-α and IFN-γ in endothelial cells in vitro.MethodsNrf2 knockout mice were exposed to cigarette smoke (CS) for 4 weeks, and the down-regulated genes affecting vascularity in the whole lung were identified by microarray analysis. This analysis revealed that the mRNA expression of AmotL1 decreased in response to CS when compared with air exposure. To confirm the protein levels that were indicated in the microarray data, we determined the expression of AmotL1 in lung tissues obtained from patients with COPD and also determined the expression of AmotL1, NFκB and IκBα in cultured normal human lung microvascular endothelial cells (HLMVECs) that were stimulated by TNF-α and IFN-γ.ResultsWe found that the number of AmotL1-positive vessels decreased in the emphysema lungs compared with the normal and bronchial asthmatic lungs. IFN-γ pretreatment diminished the TNF-α-induced AmotL1 in the cultured HLMVECs by blocking the degradation of IκBα.ConclusionsThese results suggested that IFN-γ exhibits anti-angiogenesis effects by regulating the expression of TNF-α-induced AmotL1 via NFκB in emphysema lungs.     

Acute Liver Failure from Tumor Necrosis Factor-α Antagonists: Report of Four Cases and Literature Review

Digestive Diseases and Sciences - Tumor necrosis factor-α antagonists (anti-TNF-α) have been associated with drug-induced liver injury. However, cases of anti-TNF-α-associated acute...     

Tumor Necrosis Factor-α Plays an Initiating Role in Extracorporeal Circulation-induced Acute Lung Injury

Background

Despite advances in critical care, the mortality rate for patients with acute lung injury (ALI) remains high. The aim of this study was to test the hypothesis that tumor necrosis factor-α (TNF-α) plays an initiating role in the onset of extracorporeal circulation (ECC)-induced ALI.

Methods

Eight New Zealand rabbits subjected to 1 h of ECC and 40 min of observation after termination of ECC were used for monitoring pulmonary nociceptor activity. Fifty Sprague-Dawley (SD) rats that received 2 h of ECC and 4 h of rest were used to measure the pulmonary function and inflammatory cytokines release, including total cells, neutrophils, and TNF-α in bronchoalveolar lavage (BAL) and white blood cell (WBC) and neutrophils in blood. An additional 40 SD rats were randomized to pretreatment with inhalation of phosphate buffer solution (control group), IgG (IgG inh group), or TNF-α antibody (anti-TNF-α inh group) and venous injection of TNF-α antibody (anti-TNF-α iv group). After 2 h of ECC and 4 h of rest, the arterial blood and BAL fluid were collected for measurement of arterial oxygen pressure (PaO₂) and inflammatory cytokines release. The left-lower-lung tissues of animals were stained with hematoxylin & eosin (H&E).

Results

The results demonstrated that the activities of airway nociceptor and TNF-α release were similarly upregulated at the early stage and in a time-related manner in ECC-induced ALI. Pretreatment with TNF-α antibody inhalation, but not venous injection, improved pulmonary function, inhibited pulmonary inflammation, and attenuated pulmonary histopathological changes after ECC.

Conclusion

We concluded that TNF-α played an important role in the pathogenesis of ALI and acted as an initiating cytokine at the early stage of ECC-induced ALI.     

Diallyl Trisulfide Inhibits Tumor Necrosis Factor-α Expression in Inflammed Mucosa of Ulcerative Colitis

The present study aimed to investigate the effect of diallyl trisulfide (DATS) on tumor necrosis factor (TNF)-α expression in inflammed mucosa of ulcerative colitis and its possible mechanism. Colonic biopsies from ulcerative colitis were treated with 0, 1, 5, and 10 μ M DATS for 24 hr. Lactate dehydrogenase (LDH) activities and concentrations of TNF-α in supernatants were measured. mRNA expressions of TNF-α in biopsies were analyzed by RT-PCR. The expression of NF-κ B P65 in tissues was studied by immunohistochemistry. Concentrations of TNF-α in supernatants of biopsies treated with 5 and 10 μ M DATS were lower than those of untreated biopsies. There were fewer lamina propria mononuclear cells whose NF-κ B P65 expression in nuclei was positive, and less mRNA expression of TNF-α in biopsies treated with 10 μ M DATS than in untreated biopsies. There were no differences in LDH activities in supernatants between tissues treated with DATS and untreated tissues. DATS could downregulate TNF-α production and inhibit NF-κ B activation in lamina propria mononuclear cells of inflammed mucosa, without any effect on the viability of colonic tussue cells.     

Transforming Growth Factor-β1 and Tumor Necrosis Factor-α are Associated with Clinical Severity and Airflow Limitation of COPD in an Additive Manner

Background

The role of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) in chronic obstructive pulmonary disease (COPD) is controversial. The purpose of this study was to assess the relationships among polymorphisms, clinical phenotypes, and the serum levels of TNF-α and TGF-β1.

Methods

Polymorphisms of promoters of TNF-α (rs 361525 and rs 1800629) and TGF-β1 (rs 1800469) in 110 COPD patients, 110 nonsmoker health controls without COPD, and 34 smokers were evaluated. Pulmonary functions, chest computed tomography, TGF-β1, and TNF-α were assessed.

Results

The genetic polymorphism of TNF-α (rs 361525) was associated with COPD. More severe COPD patients had higher serum levels of TNF-α and TGF-β1; moreover, serum levels of TGF-β1of mild COPD patients were higher than normal controls. All of the studied subjects were divided into four groups by the 95th percentile value of control as cutoff serum value of TGF-β1 (224.35 ρg/ml) or TNF-α (17.56 ρg/ml) to define the high value of TGF-β1 or TNF-α, which are higher than those cutoff of values (>224.35 or 17.56 ρg/ml). The FEV₁ of the group with high TGF-β1 + low TNF-α or low TGF-β1 + high TNF-α or high TNF-α + high TGF-β1 was lower than the group with low TGF-β1 + low TNF-α group. Moreover, the lowest value of FEV₁ was in the group with high TNF-α + high TGF-β1.

Conclusions

The genetic polymorphism of the TNF-α is associated with COPD. Both TGF-β1 and TNF-α modulate clinical severity and airflow limitation in an additive manner.     

Temporal Expression of Tumor Necrosis Factor-α and Nitric Oxide Synthase 2 in Rat Small Intestine After Endotoxin

Temporal changes in tumor necrosis factor- (TNF-) and nitric oxide synthase 2 (NOS 2) were evaluated in segments of duodenum, jejunum, and ileum removed from male Sprague-Dawley rats 30, 60, 120, 180, and 240 min after lipopolysaccharide (LPS), 5 mg/kg, intreperitoneally. Plasma was assayed for TNF- and for nitrate/nitrite (NO_x). Intestinal and plasma TNF- were elevated by 60 min after LPS and were back to control levels by 180 min. For control rats, NOS 2 was detected in the ileum, but not in the duodenum or the jejunum. In rats treated with LPS, NOS 2 was detected in all areas of the intestine at 120 min and was greatest at 240 min. Plasma NO_x was elevated at 120 min and continued to increase to 240 min. The time course of changes in intestinal TNF- and NOS 2 were similar to those reported for other tissues and suggest that the early and late actions of the LPS on the intestine may involve both mediators.     

Interleukin-1β and Tumor Necrosis Factor-α Induce Chemokine and Matrix Metalloproteinase Gene Expression in Human Colonic Subepithelial Myofibroblasts

Background: Colonic subepithelial myofibroblasts may play a role in the inflammatory responses and in extracellular matrix (ECM) metabolism. In this study, we investigated the effects of interleukin (IL)-1 β and tumor necrosis factor (TNF)- α on chemokine (IL-8 and monocyte chemoattractant protein (MCP)-1) and ECM turnover (proliferation of subepithelial myofibroblasts, and secretion of ECM and matrix metalloproteinases (MMPs) in colonic subepithelial myofibroblasts. Methods: Human colonic sub-epithelial myofibroblasts were isolated using the method described by Mahida et al. (4). Chemokine and MMP expressions were determined by ELISA and Northern blotting. Nuclear factor (NF)- &#115 B and NF-IL6 DNA binding activities were evaluated by electrophoretic gel mobility shift assays (EMSA). Results: IL-1 β and TNF- α did not affect the proliferation of subepithelial myofibroblasts, but stimulated the secretion of types I and IV collagens weakly. Unstimulated subepithelial myofibroblasts secreted a large amount of MMP-2, but a small amount of IL-8, MCP-1 and MMP-1. IL-1 β and TNF- α both induced a dose- and time-dependent increase in IL-8, MCP-1 and MMP-1 secretion, and weakly stimulated MMP-2 secretion. IL-1 β and TNF- α both rapidly evoked NF- &#115 B DNA-binding activity. The inhibition of NF- &#115 B activation markedly blocked both IL-1 β - and TNF- α -induced IL-8 and MCP-1 mRNA expression, but did not affect MMP-1 mRNA expression. Conclusions: These observations indicate that chemokine secretion and ECM metabolism are collectively regulated by the proinflammatory cytokines, IL-1 β and TNF- α , in colonic subepithelial myofibroblasts. Thus, colonic subepithelial myofibroblasts may play an important role in the pathophysiology of inflammation in the colon.