Extended indications for anti‐tumor necrosis factor‐α therapy

Tumour necrosis factor‐α is a pleiotropic cytokine which has a broad range of actions in inflammation, infection and immunity. TNF‐α is supposed to play a crucial role in the pathogenesis of various autoimmune diseases. TNF‐α blocking agents have been demonstrated to be highly effective in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and juvenile rheumatoid arthritis. TNF‐α inhibitors also have been tried with other rheumatic diseases and have emerged as promising treatments. We here review the current evidences of effectiveness of the anti‐TNF‐α therapy in various autoimmune diseases.     

Increased apoptosis in HepG2.2.15 cells with hepatitis B virus expression by synergistic induction of interferon‐γ and tumour necrosis factor‐α

Background: Interferon‐γ (IFN‐γ) and tumour necrosis factor‐α (TNF‐α) were thought to be important immune mediators in host defence against hepatitis B virus (HBV) infection. Aims: To examine the synergistic effect of IFN‐γ and TNF‐α on HBV‐expressing HepG2.2.15 cells and its potential mechanisms. Methods: Cell viability was quantitatively measured by 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl tetrazolium bromide assay. Cell morphology was captured using light microscopy. The typical DNA ladder test was performed using agarose gel electrophoresis. HBsAg and HBeAg titre changes were quantified by the enzyme‐linked immunosorbent assay method. Gene expression was analysed using cDNA macroarrays. Results: Interferon‐γ (1000 U/ml) alone or combined with TNF‐α (5 ng/ml) treatment resulted in apoptosis in HepG2.2.15 cells, but no significant apoptosis in the parent non‐virus expressing HepG2 cells. IFN‐γ‐ and TNF‐α‐mediated apoptosis was reduced by lamivudine treatment in HepG2.2.15 cells. IFN‐γ combined with TNF‐α reduced the titre of hepatitis B surface antigen and hepatitis B e antigen in the HepG2.2.15 cell line. For apoptosis‐related gene changes, IFN regulatory factor 1 (IRF‐1) (12.2‐fold), c‐myc (V00568 4.7‐fold, L00058 2.4‐fold) and caspase 7 (2.3‐fold) genes were upregulated in the combination treatment group. Conclusion: Interferon‐γ and TNF‐α play a role in the cell death of HBV‐expressing HepG2.2.15 cells. Expression of HBV leads to IFN‐γ‐ and TNF‐α‐mediated apoptosis in the cells. Increased IRF‐1, c‐myc and caspase 7 gene expression may be responsible for the synergistic induction of apoptosis by IFN‐γ and TNF‐α.     

Adverse effects of tumour necrosis factor‐α blocking agents

Tumor necrosis factor α (TNF‐α) blocking agents have been proved to be very effective in the treatment of various inflammatory rheumatic diseases which are refractory to conventional disease‐modifying antirheumatic drugs. However, anti‐TNF‐α therapy may have adverse effects on host defence against infectious agents in which TNF‐α plays a pivotal role. In addition, there are reports about neurologic, autoimmune, cardiac, and malignant diseases associated with TNF‐α blocking agents. This article summarizes the adverse effects and safety of these agents.     

Inhibition of hepatic tumour necrosis factor‐α attenuates the anandamide‐induced vasoconstrictive response in cirrhotic rat livers

Background: Increased anandamide, an endocannabinoid that interacts with both cannabinoid CB₁ and CB₂ receptors, can induce hepatic vasoconstrictive responses that contribute to the increased intrahepatic resistance (IHR) in cirrhotic rats. Chronic endotoxaemia and the subsequent release of tumour necrosis factor‐α (TNF‐α) are suggested to result in increased anandamide in cirrhotic livers. Thalidomide, which inhibited TNF‐α effectively, has been used clinically in states of chronic TNF‐α elevation with encouraging results. Aims: This study explores the possible effects of thalidomide on hepatic endocannabinoids and microcirculation of cirrhotic rats. Methods: Portal venous pressure (PVP), superior mesenteric arterial blood flow (SMA BF), hepatic TNF‐α, interleukin (IL‐6), protein expression of CB₁ and CB₂ receptor and thromboxane synthase (TXS) were measured in bile duct‐ligated (BDL) rats receiving 1‐month of vehicle (BDL‐V) or thalidomide (BDL‐thalido). The degree of hepatic fibrosis was also assessed. In the liver perfusion system, IHR and concentration–response curves of the portal perfusion pressure to anandamide were evaluated. Results: In BDL‐thalido rats, PVP, IHR and hepatic levels of TNF‐α and IL‐6, protein expression of CB₁ receptors, TXS and hepatic fibrosis were lower than in BDL‐V rats. In BDL‐thalido rat livers, the attenuation of the vasoconstrictive response to anandamide was associated with an upregulation of the CB₂ receptor and a downregulation of the CB₁ receptor. Nevertheless, SMA BF was not different between BDL‐thalido and BDL‐V rats. Conclusions: Thalidomide decreased the PVP and IHR through the attenuation of anandamide‐induced constrictive response, decreasing the production of TNF‐α, IL‐6 and TXA₂ in the liver and the suppression of hepatic fibrogenesis of rats with biliary cirrhosis of this study.     

Severe cardiomyopathy following treatment with the tumour necrosis factor‐α inhibitor adalimumab for Crohn's disease

Adalimumab belongs to the group of tumour necrosis factor‐α inhibitors and has been approved for the treatment Crohn's Disease since 2007. Herein we report a severe adverse reaction to adalimumab in a 25‐year‐old female patient. One week after the initial‐dose of adalimumab (160 mg), which was initiated due to an acute exacerbation of Crohn's disease, the patient developed a fulminant cardiomyopathy. In severe cardiogenic shock, the patient required an extracorporeal membrane‐oxygenation system for 8 days until cardiac recovery.     

Agrocybe aegerita polysaccharide combined with chemotherapy improves tumor necrosis factor‐α and interferon‐γ levels in rat esophageal carcinoma

Natural compounds have generated great interest as alternative treatments of diseases like cancer. Here, we investigated the anti‐tumor mechanism of one such compound, Agrocybe aegerita polysaccharide, by assessing expression of tumor necrosis factor‐α (TNF‐α) and interferon‐γ (IFN‐γ) in rat esophageal carcinoma (EC). EC was induced in healthy Wistar rats by methyl‐n‐amyl nitrosamine. Subsequently, rats were administered cancer treatment daily for 4 weeks, as follows: the normal control group (the only group not treated with methyl‐n‐amyl nitrosamine) and model group received only distilled water; the chemotherapy group received tegafur treatment; and the combination group received tegafur combined with A. aegerita polysaccharide. In normal and combination groups, body weight increased gradually after each week of treatment (P < 0.05), while body weights did not change in model and chemotherapy groups. Using enzyme linked immunosorbent assay, we found serum TNF‐α was lower in the combination group (31.56 ± 7.20 pg/L) than either the model (46.24 ± 8.52 pg/L) or chemotherapy (52.39 ± 9.16 pg/L) group, and, while higher, was more similar to the normal controls (25.08 ± 2.93 pg/L; P < 0.05), a finding that was confirmed by the immunohistochemistry of esophageal samples. In contrast, serum IFN‐γ was higher in the combination group (97.20 ± 10.92 pg/L) than in either the model (76.11 ± 11.92 pg/L) or chemotherapy (76.04 ± 9.85 pg/L) group, but lower than in the normal group (117.56 ± 10.88; P < 0.05), also confirmed by immunohistochemistry. Therefore, Agrocybe aegerita polysaccharide, when combined with chemotherapy, can regulate immune function in EC, potentially by modulating cytokine activity, specifically downregulation of TNF‐α and upregulation of IFN‐γ.     

Caspase activation during hepatocyte apoptosis induced by tumor necrosis factor‐α in galactosamine‐sensitized mice

Abstract: Background/Aims: To clarify the mechanism of hepatocyte apoptosis induced by tumor necrosis factor‐α (TNF‐α), caspase cascade and ceramide formation were investigated in the liver of D‐galactosamine (GalN)‐sensitized mice treated with TNF‐α. Methods: Seven‐week‐old male BALB/c mice were intraperitoneally injected with 20 mg GalN 30 min prior to the intravenous injection of recombinant mouse TNF‐α (0.5 μg/mouse). Cytochrome c release and processing of procaspases in the liver were analyzed by Western blotting. Activities of caspases were measured using chromogenic peptides as substrates. Ceramide content was determined using Escherichia coli diacylglycerol kinase. Results: Apoptosis of hepatocytes was observed in mice treated with both GalN and TNF‐α (GalN/TNF‐α), but not GalN or TNF‐α alone. Activation of caspases‐9 and ‐3, and cytochrome c release were observed only in liver from mice treated with GalN/TNF‐α. In a cell‐free system, processing of procaspases‐9 and ‐3, and cytochrome c release were observed in the postnuclear fraction of liver obtained from GalN/TNF‐α‐treated mice, but not in that from control mice. Processing of procaspase‐3 was inhibited by a caspase‐9 inhibitor, but not by inhibitor for caspase‐8 or ‐2. In a reconstitution assay system, procaspase‐9 processing occurred, when both cytosol and membrane fractions were obtained from the liver of mice treated with GalN/TNF‐α. Ceramide accumulation was observed only in apoptotic liver and preceded cytochrome c release and caspase activation. Conclusion: Cytochrome c release and caspase‐9 activation are required for the activation of executor caspase‐3 in TNF‐α‐induced hepatocyte apoptosis, but caspases‐8 and ‐2 play, if any, a minimal role. Ceramide may be implicated in this apoptotic process.     

Experience of antitumor necrosis factor‐α therapies in Taiwan

Background: Etanercept (Enbrel), was the first approved biologics in Taiwan for rheumatoid arthritis (RA), juvenile RA (JRA), psoriatic arthritis and ankylosing spondylitis. Approximately 500 patients with RA were under etanercept therapy by April 2006. Aim: We aimed to review the current status of biological agents use in the treatment of rheumatic diseases in Taiwan. Methods: MEDLINE database (January 1966 to February 2006) was searched by MeSH terms, limited to Taiwan by author affiliations. All known principal clinical investigators and pharmaceutical companies in Taiwan were contacted for unpublished information about this issue. Results: Six articles including two clinical trials, two case series and two preclinical studies were found in MEDLINE since January 1966. A 12‐week double‐blind placebo‐controlled study of 58 patients with active adult RA in Taiwan revealed better efficacy than results in Western countries. For JRA, two studies reported good results in polyarticular type JRA but fair response in systemic type. Adalimumab (Humira, Abbott) and Alefacept (Ameviev, Biogen) had completed their local trials in RA and psoriasis but they are not yet available in Taiwan. Widespread usage of biologics has been limited due to restricted insurance coverage policy only to the refractory patients with RA. Some herbs demonstrating TNF‐α inhibition properties are under exploratory clinical trials. Conclusions: Etanercept showed better efficacy in patients with adult RA in Taiwan than Western countries. Some herbs demonstrated TNF‐α inhibition and are under laboratory and clinical investigations.     

Effect of interferon α, γ, and tumor necrosis factor α on the HLA-A,B, C expression of cell lines derived from human liver

ABSTRACT— Our study was undertaken to determine whether human recombinant interferon α(rIFNα), γ(rIFNγ), and tumor necrosis factor α(rTNFα) exert an effect on the HLA-A, B, C expression of human liver cell lines. The HLA-A, B, C expression was assayed by immunoperoxidase staining and enzyme-linked immunosorbent assay. rIFNα and γ enhanced the HLA-A, B, C expression of the three cell lines tested, Chang cells, SK-Hep-1, and PLC/PRF/5. The activity of rIFNγ proved more than 8000 times more potent than that of rIFNα in Chang cells, 30 times in SK-Hep-1, and 20 times in PLC/PRF/5, respectively. rTNFα also enhanced the HLA-A, B, C expression of the three cell lines. The enhancement of HLA-A, B, C expression by rIFNα and γ reached a peak on day 3, and that by rTNFα on day 5. These findings suggest that IFNα, IFNγ, and TNFα may play similar roles in enhancement of HLA-A, B, C expression of hepatocytes in hepatitis and hepatoma cells.     

Peroxisome proliferator activated receptor‐γ, leptin and tumor necrosis factor‐α mRNA expression during very low calorie diet in subcutaneous adipose tissue in obese women

Background

PPARγ, leptin and TNFα are three major factors that play a key role in influencing adipocyte differentiation and both adipose tissue function and metabolism. However, the regulation of these three genes during a dynamic period of weight loss is unknown. We therefore investigated the concomitant regulation of the mRNA expression of PPARγ, leptin and TNFα in adipose tissue during a 21‐day very low calorie diet (VLCD) in 12 non‐diabetic obese women.

Methods

The mRNA levels of PPARγ, leptin and TNFα were quantified by quantitative RT‐competitive PCR in abdominal subcutaneous adipose tissue before and during VLCD (940 kcal/day).

Results

VLCD induced weight loss (∼6 kg) and improved insulin sensitivity. Simultaneously, VLCD induced the reduction in the adipose tissue mRNA abundances of PPARγ (−13%, p<0.05) and of leptin (−58%, p<0.005), whereas TNFα mRNA levels increased (+78%, p<0.005). PPARγ and leptin mRNA levels were correlated before (r=0.778, p<0.01) and after VLCD (r=0.797, p<0.01). Serum HDL‐cholesterol concentrations were positively associated with PPARγ (r=0.696, p<0.03) and leptin (r=0.806, p<0.01) mRNA levels.

Conclusions

The increase in TNFα mRNA levels suggested that a local increased expression of this cytokine in adipose tissue might play a role in the control of the fat mass during weight loss. PPARγ and leptin mRNA levels were positively associated both before and after VLCD, suggesting that common regulatory mechanism(s) might control their expression. More strikingly, we found strong positive correlations between circulating HDL‐cholesterol and both PPARγ and leptin mRNA levels, suggesting the existence of physiological links between circulating lipoprotein metabolism and adipose tissue function. Copyright © 1999 John Wiley & Sons, Ltd.