Protein Levels Of Tumor Necrosis Factor Research Articles

TNF is a critical cytokine in age-related dry eye disease

Aging is a complex biological process that is characterized by low-grade inflammation, called inflammaging. Aging affects multiple organs including eye and lacrimal gland. Tumor necrosis factor (TNF) is a pleiotropic cytokine that participates in inflammation, activation of proteases such as cathepsin S, and formation of ectopic lymphoid organs. Using genetic and pharmacological approaches, we investigated the role of TNF in age-related dry eye disease, emphasizing the ocular surface and lacrimal gland inflammation. Our results show the increased protein and mRNA levels of TNF in aged lacrimal glands, accompanied by increased TNF, IL1β, IL-18, CCL5, CXCL1, IL-2, IL-2 receptor alpha (CD25), IFN-γ, IL-12p40, IL-17, and IL-10 proteins in tears of aged mice. Moreover, genetic loss of the Tnf−/− in mice decreased goblet cell loss and the development of ectopic lymphoid structures in the lacrimal gland compared to wild-type mice. This was accompanied by a decrease in cytokine production. Treatment of mice at an early stage of aging (12-14-month-old) with TNF inhibitor tanfanercept eye drops for eight consecutive weeks decreased cytokine levels in tears, improved goblet cell density, and decreased the marginal zone B cell frequency in the lacrimal gland compared to vehicle-treated animals. Our studies indicate that modulation of TNF during aging could be a novel strategy for age-related dry eye disease.

Mechanism of Huoxue Tongluo Decoction in treatment of erectile dysfunction caused by ischemic stroke based on network pharmacology

ObjectiveTo study the therapeutic effect of Huoxue Tongluo Decoction (HXTLD) on erectile dysfunction caused by ischemic stroke and identify the mechanisms involved. MethodsNetwork pharmacology was used to predict the key active ingredients and targets of HXTLD. Surgical methods were used to create a rat model of ischemic stroke. The rats were then given a suspension of HXTLD by ig administration. Erectile function was evaluated by Apomorphine (APO) induction. Real-time fluorescence quantitative reverse transcription-polymerase chain reaction (Real-time PCR) and Western blotting were used to detect the expression of related mRNAs and proteins in rat penile corpus cavernous tissue and brain tissue. Hematoxylin & Eosin (HE) staining was used to investigate structural changes in the penile cavernous tissue. ResultsNetwork pharmacology showed that tumor necrosis factor (TNF), nitric oxide synthase 3 (eNOS), and vascular endothelial growth factor (VEGF) were the key targets of HXTLD in the treatment of erectile dysfunction caused by ischemic stroke. Experimental studies showed that HXTLD improved erectile dysfunction caused by ischemic stroke. HE results showed that HXTLD improved the structure of the corpus cavernosa. HXTLD also inhibited the expression of TNF and VEGF proteins in penile tissue (P < 0.05) and enhanced the expression of eNOS protein in penile tissue (P < 0.05). ConclusionHXTLD improved the erectile function of rats with erectile dysfunction caused by ischemic stroke by regulating the mRNA and protein levels of TNF, eNOS and VEGF.

Effect of Asthma on Erectile Dysfunction in Rats as Determined by Biological Network Analysis.

BackgroundWe explored the effect of asthma on erectile dysfunction (ED) and the effects of the expression of related proteins.Material/MethodsWe used a bioinformatics database to predict the targets and pathways associated with asthma and ED. The rat model of asthma was caused by an ovalbumin solution. The number of erections in 30 min was observed by injecting apomorphine into the neck at a dose of 100 μg/kg. Rats with no erection were regarded as the model group (group B), and the previous random 6 normal rats were regarded as the control group (group A). We used hematoxylin and eosin (HE) to compare the tissue structure of the cavernous body of the penis. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to determine the expression levels of insulin (INS), interleukin 6 (IL6), albumin (ALB), tumor necrosis factor (TNF), and vascular endothelial growth factor A (VEGFA) at both the protein and messenger ribonucleic acid (mRNA) levels.ResultsHE staining results show that compared with group A, the blood sinus distribution of the cavernous body in group B was disordered, and the density of endothelial cells and smooth muscle cells decreased significantly. Western blotting and RT-qPCR showed that the levels of IL6, TNF, and VEGFA protein and mRNA in group B were significantly higher (P<0.05) than those in group A. The levels of INS and ALB were not significantly different between the 2 groups.ConclusionsOn the basis of the results, we found that asthma caused pathological changes in the penises of rats and led to reduced erectile function via changes in the expression of IL6, TNF, and VEGFA proteins.

LPS로 유도된 RAW 264.7세포에 대한 벼메뚜기(Oxya chinensis sinuosa) 에탄올 추출물의 항염증 효과

본 연구에서는 벼메뚜기 에탄올 추출물의 항염증 효능을 분석하기 위해 LPS로 염증 유도된 RAW 264.7 세포를 이용하였다. OCE의 항염증 효능을 확인 하기 위해서, 염증 유도된 RAW 264.7 세포에 대해 OCE 농도 의존적으로 염증성 사이토카인인 TNF-<TEX>${\alpha}$</TEX>와 IL-6의 유전자발현 및 단백질 생성을 감소시킴을 real-time PCR과 ELISA로 확인하였다. 또한, NF-<TEX>${\kappa}B$</TEX> p65의 핵으로 이동이 차단됨을 면역형광염색으로 확인하였으며, iNOS와 COX-2 단백질 발현을 감소시키는 것을 Western blot 분석으로 확인하였다. 이상의 연구결과를 통해 벼메뚜기는 염증에 의한 NF-<TEX>${\kappa}B$</TEX> p65의 활성과 TNF-<TEX>${\alpha}$</TEX>와 IL-6의 생성과 iNOS 및 COX-2의 발현을 억제하는 항염증 효능을 갖고 있는 것을 확인하였다. Although the grasshopper Oxya chinensis sinuosa has long been used as food in Korea, there is little data on its functional effects. In this study, we investigated the anti-inflammatory effect of O. c. sinuosa ethanol extract (OCE) in RAW 264.7 mouse macrophage cells treated with lipopolysaccharide (LPS) for induction of inflammation. First, we determined that there is no cytotoxicity at <TEX>$2,000{\mu}g/ml$</TEX> or less of OCE in RAW 264.7 cells. To evaluate the anti-inflammatory effects of OCE, we investigated expression levels of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-<TEX>${\alpha}$</TEX> and interleukin (IL)-6, and pro-inflammatory enzymes such as inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) in LPS-induced RAW 264.7 cells. In addition, we examined whether OCE could inhibit translocation of NF-<TEX>${\kappa}B$</TEX> p65 into the nucleus in LPS induced RAW 264.7 cells. As a result, we found that the mRNA and protein levels of TNF-<TEX>${\alp</TEX><TEX>ha}$</TEX> and IL-6 decreased in LPS-induced RAW 264.7 cells after treatment with OCE in a dose-dependent manner. In addition, we confirmed a <TEX>$2,000{\mu}g/ml$</TEX> concentration of OCE inhibited translocation of NF-<TEX>${\kappa}B$</TEX> p65 by immunnostaining and Western blot analysis, and a decrease in the protein expression levels of iNOS and COX-2. Accordingly, we suppose that OCE has an anti-inflammatory effect through down-regulation of TNF-<TEX>${\alpha}$</TEX>, IL-6, iNOS, and COX-2 related to <TEX>${\kappa}B$</TEX> p65 inflammatory signaling pathways.

Brain Death–Induced Inflammatory Activity in Human Pancreatic Tissue

Long-term insulin independence after islet transplantation depends on engraftment of a large number of islets. However, the yield of pancreatic islets from brain-dead donors is negatively affected by the up-regulation of inflammatory mediators. Brain death is also believed to increase tissue factor (TF) expression, contributing to a low rate of engraftment. We conducted a case-control study to assess brain death-induced inflammatory effects in human pancreas. Seventeen brain-dead patients and 20 control patients undergoing pancreatectomy were studied. Serum tumor necrosis factor (TNF), interleukin (IL) 6, IL-1β, interferon (IFN) γ, and TF were measured using enzyme-linked immunosorbent assay kits. Gene expressions of these cytokines and TF were evaluated by reverse transcriptase quantitative polymerase chain reaction. Protein quantification was performed by immunohistochemistry in paraffin-embedded pancreas sections. Brain-dead patients had higher serum concentrations of TNF and IL-6 and increased TNF protein levels compared to controls. The groups had similar TNF, IL-6, IL-1β, and IFN-γ messenger RNA levels in pancreatic tissue. Reverse transcriptase quantitative polymerase chain reaction revealed TF messenger RNA up-regulation in controls. Immunohistochemical analyses showed that brain-dead patients had increased TNF protein levels compared to controls. Brain death induces inflammation evidenced by the up-regulation of TNF in serum and pancreatic tissue. Blocking the expression of key inflammatory mediators in brain-dead donors should be evaluated as a new approach to improve the outcomes of islet transplantation.

O-037 Modulation of Inflammatory Processes in DSS-induced Colitis Models versus Gastrointestinal Acute Radiation Syndrome with AVX-470m, an Oral Polyclonal Anti-TNF Antibody

Development of improved therapies for inflammatory bowel disease (IBD) requires animal models that elucidate underlying mechanisms of disease. Acute radiation syndrome (ARS) has devastating consequences in the gastrointestinal (GI) tract driven in part by cytokine-mediated inflammation that closely resembles the pathophysiology of IBD. Tumor Necrosis Factor (TNF) is central to the dysregulated inflammatory response in IBD, and is strongly implicated in GI ARS. In this study AVX-470 m, a bovine polyclonal neutralizing antibody for murine TNF, is used to characterize the pathogenesis of GI damage in models of GI ARS and IBD. Colitis was induced in C57BL/6 mice by including 3% DSS in drinking water for 5 days. Other C57BL/6 mice were irradiated with 15.9 Gy (∼LD80/30) from a 60Co gamma source, with partial bone marrow shielding. Animals were dosed BID with AVX-470 m (10 mg/day) or saline by oral gavage for up to 14 days. In colon and jejunum tissues, relative mRNA expression levels of cytokines and immune markers was measured by qPCR (Taqman), and protein expression was analyzed by immunohistochemistry (IHC) in paraffin embedded, formalin fixed tissue sections. Both mRNA and protein levels of TNF were increased in colon and jejunum tissue, respectively, in the colitis and GI ARS models. IL-1β, IL-6, MMP9, ICAM-1, and TNFR2 mRNA levels were increased in both models, but IL12p40 was increased only in the colitis model, and no change in TNFR1 mRNA levels was detected in either model. Protein expression of MPO was increased in both the colitis and GI ARS models. These data show a remarkable correlation of inflammatory responses between these 2 models of GI injury. In contrast, CD68 and CD3 protein were increased in colon tissue in the colitis model, but neither protein was detected in jejunum in the GI ARS model, suggesting a reduced T-cell component in GI ARS, perhaps due to destruction of these cells by the high levels of ionizing radiation. In both colitis and GI ARS models, treatment with AVX-470 m resulted in a significant decrease in TNF mRNA and protein expression in colon and jejunum tissues, respectively. AVX-470 m also decreased MPO protein expression, and reduced MMP9 mRNA expression, in both models. In the colitis model, IL-6 mRNA levels were decreased by AVX-470 m treatment in colon tissue, while in the GI ARS model IL-6 mRNA levels were transiently increased in jejunum tissue. No change in mRNA levels for ICAM-1 or TNFR1 were seen in either model following AVX-470 m treatment. These studies show that inflammatory responses in colitis and GI ARS models share a common TNF-mediated neutrophilic component in the colon and jejunum, respectively, but differ with respect to immune cell involvement in response to injury. Further studies will reveal whether these differences reflect variability in timing, tissue localization, or response to the different insults. The fact that AVX-470 m is effective in both models highlights the central role of TNF in inflammation in the GI tract, and supports the therapeutic potential of an oral anti-TNF antibody as a gut-targeted treatment for multiple GI inflammatory diseases.

AB0073 Maternal collagen-induced arthritis and co-administration of etanercept change tnf protein level in placenta and epiphyseal cartilage in fetuses

BackgroundEtanercept interferes with the tumor necrosis factor (TNF) and is widely used in various autoimmune diseases. However, its developmental toxicity has not been fully established.ObjectivesThe aim of the study was...

The Transcription Factor NFATp Plays a Key Role in Susceptibility to TB in Mice

In T cells, the transcription factor nuclear factor of activated T cells p (NFATp) is a key regulator of the cytokine genes tumor necrosis factor (TNF) and interferon-γ (IFN-γ). Here, we show that NFATp-deficient (NFATp−/−) mice have a dramatic and highly significant increase in mortality after Mycobacterium tuberculosis (MTb) infection as compared to mortality of control animals after MTb infection. Animals deficient in NFATp have significantly impaired levels of TNF and IFN-γ transcription and protein expression in naïve or total CD4+ T cells, but display wild-type levels of TNF mRNA or protein from MTb-stimulated dendritic cells (DC). The rapid mortality and disease severity observed in MTb-infected NFATp−/− mice is associated with dysregulated production of TNF and IFN-γ in the lungs, as well as with increased levels of TNF, in their serum. Furthermore, global blocking of TNF production by injection of a TNF neutralizaing agent at 6 weeks, but not 12 weeks, post-MTb-infection further decreased the survival rate of both wild-type and NFATp−/− mice, indicating an early role for TNF derived from cells from the monocyte lineage in containment of infection. These results thus demonstrate that NFATp plays a critical role in immune containment of TB disease in vivo, through the NFATp-dependent expression of TNF and IFN-γ in T cells.

Tumor necrosis factor is necessary, but not sufficient, for castration induced prostate regression

Tumor necrosis factor (TNF) is a pro‐inflammatory cytokine that plays a vital role in immune responses. TNF is also a potent apoptotic stimulus in vitro. However, few reports have demonstrated a physiologic role for TNF induced apoptosis in vivo. Employing high field MRI (magnetic resonance imaging) to measure mouse prostate volume, we demonstrate that the extent of castration induced prostate regression is significantly reduced in mice null for either the TNF or TNFR1 genes. Wild type (WT) mice receiving soluble TNFR2 prior to castration exhibit a nearly identical reduction of prostate regression. Additionally, membrane‐bound TNF protein and TNF mRNA levels increase in the ventral lobe of rat prostate following castration. When injected into the peritoneum of TNF−/− mice at the time of castration, soluble TNF is able to restore normal levels of prostate regression. However, WT mice receiving soluble TNF in the absence of castration do not exhibit prostate regression, indicating that TNF alone is not sufficient, but must act in the context of additional castration induced signals. These findings support a physiologic role for TNF in prostate regression following androgen withdrawal. Understanding this role may lead to novel therapies for prostate cancer.J.S. Davis is supported by DOD Pre‐doctoral Training Grant #PC073208.

Reactive Oxygen Species Mediate Liver Injury Through Parenchymal Nuclear Factor-κB Inactivation in Prolonged Ischemia/Reperfusion

Nuclear factor (NF)-kappaB participates in ischemia/reperfusion (I/R) hepatic signaling, stimulating both protective mechanisms and the generation of inflammatory cytokines. After analyzing NF-kappaB activation during increasing times of ischemia in murine I/R, we observed that the nuclear translocation of p65 paralleled Src and IkappaB tyrosine phosphorylation, which peaked after 60 minutes of ischemia. After extended ischemic periods (90 to 120 minutes) however, nuclear p65 levels were inversely correlated with the progressive induction of oxidative stress. Despite this profile of NF-kappaB activation, inflammatory genes, such as tumor necrosis factor (TNF) and interleukin (IL)-1beta, predominantly induced by Kupffer cells, increased throughout time during ischemia (30 to 120 minutes), whereas protective NF-kappaB-dependent genes, such as manganese superoxide dismutase (Mn-SOD), expressed in parenchymal cells, decreased. Consistent with this behavior, gadolinium chloride pretreatment abolished TNF/IL-1beta up-regulation during ischemia without affecting Mn-SOD levels. Interestingly, specific glutathione (GSH) up-regulation in hepatocytes by S-adenosylmethionine increased Mn-SOD expression and protected against I/R-mediated liver injury despite TNF/IL-1beta induction. Similar protection was achieved by administration of the SOD mimetic MnTBAP. In contrast, indiscriminate hepatic GSH depletion by buthionine-sulfoximine before I/R potentiated oxidative stress and decreased both nuclear p65 and Mn-SOD expression levels, increasing TNF/IL-1beta up-regulation and I/R-induced liver damage. Thus, the divergent role of NF-kappaB activation in selective liver cell populations underlies the dichotomy of NF-kappaB in hepatic I/R injury, illustrating the relevance of specifically maintaining NF-kappaB activation in parenchymal cells.

Interleukin‐12p40 overexpression promotes interleukin‐12p70 and interleukin‐23 formation but does not affect bacille Calmette–Guérin and Mycobacterium tuberculosis clearance

Interleukin (IL)-12p40, a subunit of IL-12p70 and IL-23, has previously been shown to inhibit IL-12p70 activity and interferon-gamma (IFN-gamma) production. However, recent evidence has suggested that the role of IL-12p40 is more complex. To study the contribution of IL-12p40 to immune responses against mycobacterial infections, we have used transgenic (tg) mice overexpressing IL-12p40 under the control of a major histocompatibility complex-II promoter. The IL-12p40 transgene was expressed during steady state at concentrations of 129 +/- 25 ng/ml of serum and 75 +/- 13 ng per spleen, while endogenous IL-12p40 was hardly detectable in control littermates. Bacille Calmette-Guérin (BCG) infection strongly induced the expression of IL-12p40 transgene in infected organs, and IL-12p40 monomeric and dimeric forms were identified in spleen of IL-12p40 tg mice. Excessive production of IL-12p40 resulted in a 14-fold increase in IL-12p70 serum levels in tg mice versus non-transgenic mice. IL-23 was also strongly elevated in the serum and spleens of IL-12p40 tg mice through BCG infection. While IFN-gamma and tumour necrosis factor protein levels were similar in IL-12p40 tg and non-transgenic mice, Th2 type immune responses were reduced in IL-12p40 tg mice. The number of BCG granulomas and macrophage expressing inducible nitric oxide synthase were similar in IL-12p40 tg and non-transgenic mice. IL-12p40 tg mice were as resistant as non-transgenic mice to BCG and Mycobacterium tuberculosis infections as they could efficiently control bacillary growth. These data show that high amounts of IL-12p40 promotes IL-12p70 and IL-23 formation, but that does not affect T helper 1 type immune responses and granuloma function, thus leading to normal mycobacterial clearance in infected organs.

Resident dendritic cells are the predominant TNF-secreting cell in early renal ischemia–reperfusion injury

Renal ischemia-reperfusion injury (IRI) rapidly induces production of inflammatory mediators including, and in particular, tumor necrosis factor (TNF). Possible sources include resident parenchymal and bone marrow-derived cells as well as recruited leukocytes. Cell suspensions from kidneys subjected to IRI were examined by cell separation followed by in vitro culture and enzyme-linked immunosorbent assay (ELISA), immunoperoxidase and immunofluorescence microscopy, and multicolor flow cytometry to determine the contribution of dendritic cells (DCs) to early production of TNF and other inflammatory mediators. Secretion of TNF, interleukin (IL-6), monocyte chemoattractant protein-1 (MCP-1), and regulated on activation normal T cell expressed and secreted (RANTES) was increased in cell suspensions from IRI compared with control kidneys and was higher in DC-enriched preparations. Immunostaining identified TNF(+ve) cells that coexpressed the DC marker CD11c. Flow cytometry of bone marrow-derived (CD45(+ve)) cell populations at 24 h post-IRI demonstrated that F4/80(+ve)/CD11c(+ve) DCs remained proportionately stable and exhibit higher levels of DC maturation markers, whereas the proportion of F4/80(-ve) DCs, monocytes, neutrophils, and T cells increased. Intracellular staining for TNF confirmed that F4/80(+ve) DCs were the predominant TNF(+ve) cell and expressed higher levels than other TNF(+ve) cells. In vivo depletion of DCs from the kidney substantially attenuated TNF secretion by total and CD45(+ve) cells following IRI. The results uncover a role for resident F4/80(+ve) DCs as the predominant secretors of TNF within 24 h of IRI.

Mitogen-Activated Protein Kinase-Activated Protein Kinase 2 Regulates Tumor Necrosis Factor mRNA Stability and Translation Mainly by Altering Tristetraprolin Expression, Stability, and Binding to Adenine/Uridine-Rich Element

The mitogen-activated protein kinase (MAPK) p38/MAPK-activated protein kinase 2 (MK2) signaling pathway plays an important role in the posttranscriptional regulation of tumor necrosis factor (TNF), which is dependent on the adenine/uridine-rich element (ARE) in the 3' untranslated region of TNF mRNA. After lipopolysaccharide (LPS) stimulation, MK2-deficient macrophages show a 90% reduction in TNF production compared to the wild type. Tristetraprolin (TTP), a protein induced by LPS, binds ARE and destabilizes TNF mRNA. Accordingly, macrophages lacking TTP produce large amounts of TNF. Here, we generated MK2/TTP double knockout mice and show that, after LPS stimulation, bone marrow-derived macrophages produce TNF mRNA and protein levels comparable to those of TTP knockout cells, indicating that in the regulation of TNF biosynthesis TTP is genetically downstream of MK2. In addition, we show that MK2 is essential for the stabilization of TTP mRNA, and phosphorylation by MK2 leads to increased TTP protein stability but reduced ARE affinity. These data suggest that MK2 inhibits the mRNA destabilizing activity of TTP and, in parallel, codegradation of TTP together, with the target mRNA resulting in increased cellular levels of TTP.

Inhibition of DMXAA-Induced Tumor Necrosis Factor Production in Murine Splenocyte Cultures by NF-κB Inhibitors

The induction of cytokine synthesis within tumor tissue is a key component of the antivascular action of 5,6-dimethylxanthenone-4-acetic acid (DMXAA) in murine tumors. We previously showed that DMXAA alone induced only low amounts of tumor necrosis factor (TNF) in cultured spleen cells, but the addition of suboptimal concentrations of lipopolysaccharide (LPS) provided a costimulatory signal that resulted in 6-10-fold increase in secreted TNF. In this study we investigated the molecular pathway involved, and showed that the addition of NF-kappaB inhibitors salicylate and parthenolide reduced the levels of TNF secreted into the culture supernatants induced with DMXAA (10 microg/ml) alone or in combination with LPS (10 microg/ml). Results from gene arrays, confirmed with RT-PCR, showed that the TNF gene was not upregulated with DMXAA alone, and was only slightly increased above the level of significance when LPS was added simultaneously. This contrasted with secreted TNF protein levels, which increased 5- and 48-fold, respectively, above that in untreated cultures with DMXAA alone or in combination with LPS. In addition to TNF, protein arrays showed IL-6, IL-10, MIP-1alpha, MIP-2, and RANTES were also secreted following treatment with 10 microg/ml DMXAA alone, and IL-4, IFN-gamma, MCP-5, and TIMP-1 were additionally induced using a higher dose of 300 microg/ml DMXAA. The drug is currently showing promise in phase II combination trials, and these studies suggest that DMXAA-induced TNF production in the splenocyte cultures was not due to increased expression of the TNF gene, but through effects on NF-kappaB-dependent posttranscriptional regulation.

A Quantitative Study of Microglial—Macrophage Synthesis of Tumor Necrosis Factor during Acute and Late Focal Cerebral Ischemia in Mice

Understanding the role of tumor necrosis factor (TNF) in the life-death balance of ischemically injured neurons demands insight into the cellular synthesis of TNF, especially in the acute phase after induction of ischemia. Here, using approximated stereological methods and quantitative reverse transcription (RT) real-time polymerase chain reaction (PCR) analysis, the cellular synthesis of TNF from 30 mins to 10 days after induction of focal cerebral ischemia in mice was investigated. Reverse transcription real-time PCR analysis showed that TNF mRNA increased 2- to 3-fold within 1 hour after induction of ischemia. A significant 8-fold increase was observed at 4 hours when faintly labelled TNF mRNA-expressing and TNF immunoreactive microglial-like cells were easily identifiable in the peri-infarct and infarct. By 6 hours, TNF synthesizing cells were identified as Mac-1 immunopositive, glial fibrillary acidic protein immunonegative microglia-macrophages. The level of TNF mRNA and the numbers of TNF mRNA-expressing microglia-macrophages peaked at 12 hours, and the number of TNF immunoreactive cells at 24 hours. Neuronal TNF mRNA and TNF protein levels remained at constant, very low, levels. The data suggest that the pathophysiologically important TNF, produced in the acute phase from mins to 6 hours after an ischemic attack in mice, is synthesized by microglia-macrophages.

Pentoxifylline Ameliorates Renal Tumor Necrosis Factor Expression, Sodium Retention, and Renal Hypertrophy in Diabetic Rats

Background/Aim: Diabetic nephropathy contributes substantially to cardiovascular morbidity and mortality associated with diabetes. Urinary tumor necrosis factor (TNF) excretion is increased during diabetes and serves as an important mediator of pathological changes during the initial stages of diabetic nephropathy, including sodium retention and renal hypertrophy. We tested the hypothesis that pentoxifylline (PTF), an agent that inhibits TNF synthesis, could prevent sodium retention and renal hypertrophy during diabetes. Methods: Proximal and distal tubule TNF expression, urinary TNF excretion, sodium retention, and renal hypertrophy were examined in control, diabetic, and PTF-treated diabetic rats. Results: TNF mRNA and protein levels were increased in proximal tubule cells isolated from diabetic rats compared to control rats. In contrast, TNF expression in distal tubule cells was not increased during diabetes. PTF prevented the increase in TNF mRNA and protein in proximal tubule cells during diabetes and reduced urinary TNF excretion. PTF therapy decreased whole animal sodium retention by enhancing urinary sodium excretion in diabetic rats. In addition, PTF reduced renal hypertrophy in diabetic rats. Conclusions: The proximal tubule is an important site of TNF production during diabetes and PTF is an effective therapy for preventing the pathological changes accompanying early diabetic nephropathy.

Effect of neutralizing transforming growth factor beta1 on the immune response against Mycobacterium tuberculosis in guinea pigs.

Transforming growth factor beta (TGF-beta) is a cytokine which has been shown to suppress the antimycobacterial immune responses of humans and experimental animals. In this study, the contributions of TGF-beta to cytokine production in vivo were investigated by using the established guinea pig model of tuberculous pleurisy. Mycobacterium bovis BCG-vaccinated guinea pigs were injected intrapleurally with heat-killed virulent Mycobacterium tuberculosis. Eight days following induction of an antigen-specific pleural effusion, guinea pigs were injected intrapleurally with anti-TGF-beta1 or isotype control antibody. The following day, pleural exudates were removed, and the fluid volume and characteristics of the infiltrating cells were determined. Pleural fluid was analyzed for total interferon (IFN) and tumor necrosis factor (TNF) protein levels by using appropriate bioassays. RNA from pleural effusion cells was examined to determine TGF-beta1, TNF-alpha, IFN-gamma, and interleukin-8 mRNA levels by using real-time PCR. Proliferative responses of pleural effusion lymphocytes were examined in response to concanavalin A and purified protein derivative (PPD) in vitro. Treatment with anti-TGF-beta1 resulted in decreased pleural fluid volume and decreased cell numbers in the pleural space along with an increased percentage of lymphocytes and a decreased percentage of neutrophils. The bioactive TNF protein levels in pleural fluid were increased in guinea pigs treated with anti-TGF-beta1, while the bioactive IFN protein concentrations were not altered. Expression of TGF-beta1 and TNF-alpha mRNA was significantly increased following TGF-beta1 neutralization. Finally, PPD-induced proliferative responses of pleural cells from anti-TGF-beta1-treated animals were significantly enhanced. Thus, TGF-beta1 may be involved in the resolution of this local, mycobacterial antigen-specific inflammatory response.

Effects of antibiotic class on the macrophage inflammatory response to Streptococcus pneumoniae.

Antibiotic choice can alter host inflammation during invasive bacterial infections. Previous studies of gram-negative organisms concluded that antibiotic-mediated release of bacterial cell wall components amplifies inflammation. Less has been reported about antibiotic effect on gram-positive organisms. This study explored the hypothesis that Streptococcus pneumoniae would induce greater macrophage inflammatory mediator production when killed with cell wall active antibiotics rather than protein synthesis inhibitors. Stimulation of RAW 264.7 murine macrophages with pneumococci and oxacillin led to significantly higher inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF) accumulation than did the same concentrations of pneumococci and clindamycin. Neither antibiotic alone or in combination with lipopolysaccharide acted directly on macrophages to modify the immune response. Endotoxin contamination did not confound the results, as preincubation with polymyxin B did not change iNOS or TNF protein levels. Thus, the antimicrobial mechanism of action affects macrophage inflammatory mediator production after stimulation with pneumococci.

Cerebrospinal fluid cytokine levels and dexamethasone therapy in bacterial meningitis.

cerebrospinal fluid (CSF) levels of interleukin (IL)-1 beta and tumor necrosis factor (TNF) alpha were measured to assess the effect and application of dexamethasone (Dex) therapy for bacterial meningitis. associations between clinical findings and CSF parameters were first investigated, and prognosis was compared between 25 patients with Dex and 12 without Dex therapy. patients with the presence of disturbed consciousness showed higher CSF levels of TNF alpha (mean: 3015 pg/ml) or protein (mean: 215 mg/dl) than those without it (both, P < 0.O5). Simultaneous increase of TNF alpha (> 1000 pg/ml) and protein (> 100 g/dl) was observed in 80%, of patients with profoundly disturbed consciousness. Patients with Dex therapy presented higher TNF alpha/protein levels at diagnosis than those without Dex therapy (P < 0.05). Despite worse conditions at diagnosis, only one of 14 Dex-treated patients whose initial CSF TNF alpha levels exceeded 1000 pg/ml developed deafness. On the other hand, two of four patients without Dex therapy who had the same TNF alpha level suffered from psychomotor retardation. The differences in the frequency of sequelae between those with and without Dex therapy were significant in patients showing high TNF alpha level (P < O.05), but not in those showing high CSF levels of IL-1 beta or protein. The logistic regression analysis indicated that high CSF protein level (P < O.0001), or no Dex therapy (P=0.0001) was the independent risk factor for sequelae. although the study number was small, our observations suggested that CSF TNF alpha/protein levels reflected the neurologic severity, and implied that early Dex therapy might be beneficial for patients with prominently high TNF alpha levels.

Sublethal hemorrhage blunts the inflammatory cytokine response to endotoxin in a rat model.

Tolerance to lipopolysaccharide (LPS) induced by previous hemorrhage in mice is associated with a blunted interleukin 1 (IL-1) response, suggesting down-regulation of the cytokine cascade as a possible protective mechanism. This study was undertaken to determine whether prehemorrhage induces attenuation of the cytokine response to sepsis beyond IL-1 in a rat model and whether this response occurs at the level of gene transcription. Sprague-Dawley rats underwent sublethal hemorrhage, lethal intraperitoneal endotoxin, or sublethal hemorrhage with delayed lethal endotoxin. Animals were killed 12 hours after LPS injection or 24 hours after hemorrhage. IL-1 and tumor necrosis factor (TNF) mRNA levels were determined on total splenic RNA using reverse-transcriptase polymerase chain reaction, and serum cytokine levels were determined using enzyme-linked immunosorbent assay. Animals that received LPS alone mounted an IL-1 and TNF response (RNA and protein) much higher than animals subjected to hemorrhage alone. TNF and IL-1 gene expression and protein levels in prehemorrhaged animals that received LPS, however, were significantly lower than those of animals that received LPS alone. Hemorrhage induces early IL-1 and TNF gene expression, which blunts their subsequent expected increase after endotoxic challenge. These findings validate previously documented immune-modulated protective effects of the first insult in a two-hit model.