Possible roles of tumor necrosis factor-α and angiotensin II type 1 receptor on high glucose-induced damage in renal proximal tubular cells

Abstract

Recent studies have identified that high glucose-induced renal tubular cell damage. We previously demonstrated that high glucose treatment induced oxidative stress in human renal proximal tubular epithelial cells (RPTECs), and angiotensin II type 1 (AT1) receptor blockers reduce high glucose-induced oxidative stress in RPTEC possibly via blockade of intracellular as well as extracellular AT1 receptor. However, exact roles of tumor necrosis factor (TNF)-α and AT1 receptor on high glucose-induced renal tubular function remain unclear. N-acetyl-beta-glucosaminidase (NAG), concentrations of TNF-α/angiotensin II and p22^phox protein levels after high glucose treatment with or without AT1 receptor blocker or thalidomide, an inhibitor of TNF-α protein synthesis, were measured in immortalized human renal proximal tubular epithelial cells (HK2 cells). AT1 receptor knockdown was performed with AT1 receptor small interfering RNA (siRNA). High glucose treatment (30?mM) significantly increased NAG release, TNF-α/angiotensin II concentrations in cell media and p22^phox protein levels compared with those in regular glucose medium (5.6?mM). Candesartan, an AT1R blocker, showed a significant reduction on high glucose-induced NAG release, TNF-α concentrations and p22^phox protein levels in HK2 cells. In addition, significant decreases of NAG release, TNF-α concentrations and p22^phox protein levels in HK2 cells were observed in high glucose-treated group with thalidomide. AT1R knockdown with siRNA markedly reversed high glucose, angiotensin II or TNF-α-induced p22^phox protein levels in HK2 cells. TNF-α may be involved in high glucose-induced renal tubular damage in HK2 cells possibly via AT1 receptor signaling.     

Role of endothelin receptors and relationship with nitric oxide synthase in impaired erectile response in diabetic rats

To evaluate the protective role of bosentan (BOS), an endothelin‐1 (ET‐1) receptor antagonist, and to show the changes in rats with experimentally induced diabetic erectile dysfunction (ED), a total of 24 albino Wistar rats were allocated into four groups. Group 1 was the healthy group and Group 2 had diabetes mellitus (DM) induced by intraperitoneal injection of 60 mg kg^?1 streptozotocin (STZ). Following the establishment of DM, Group 3 and Group 4 were treated with oral BOS doses of 50 mg kg^?1 and 100 mg kg^?1, respectively, for 60 days. At the end of the treatment, we evaluated yawning and erection response to apomorphine treatment and then the animals were sacrificed. ET‐1, eNOS, iNOS, tumour necrosis factor (TNF)‐α, ET‐RA and ET‐RB mRNA expressions were analysed in cavernosal tissue. It was observed that yawning and erection response decreased in the diabetic group; however, both of these improved with BOS treatment. While ET‐1, TNF‐α and iNOS gene expressions increased, eNOS, ET‐RA and ET‐RB gene expressions decreased in the DM group compared to the healthy group. DM has a negative impact on cavernosal tissue blood flow through activating vasoconstrictor mediators in cavernosal tissue. BOS regulates significantly eNOS, iNOS and TNF‐α expressions in a dose‐dependent manner.     

SH3BP2 Cherubism Mutation Potentiates TNF‐α–Induced Osteoclastogenesis via NFATc1 and TNF‐α–Mediated Inflammatory Bone Loss

Cherubism (OMIM# 118400) is a genetic disorder with excessive jawbone resorption caused by mutations in SH3 domain binding protein 2 (SH3BP2), a signaling adaptor protein. Studies on the mouse model for cherubism carrying a P416R knock‐in (KI) mutation have revealed that mutant SH3BP2 enhances tumor necrosis factor (TNF)‐α production and receptor activator of nuclear factor‐κB ligand (RANKL)‐induced osteoclast differentiation in myeloid cells. TNF‐α is expressed in human cherubism lesions, which contain a large number of tartrate‐resistant acid phosphatase (TRAP)‐positive multinucleated cells, and TNF‐α plays a critical role in inflammatory bone destruction in homozygous cherubism mice (Sh3bp2^KI/KI). The data suggest a pathophysiological relationship between mutant SH3BP2 and TNF‐α–mediated bone loss by osteoclasts. Therefore, we investigated whether P416R mutant SH3BP2 is involved in TNF‐α–mediated osteoclast formation and bone loss. Here, we show that bone marrow–derived M‐CSF–dependent macrophages (BMMs) from the heterozygous cherubism mutant (Sh3bp2^KI/+) mice are highly responsive to TNF‐α and can differentiate into osteoclasts independently of RANKL in vitro by a mechanism that involves spleen tyrosine kinase (SYK) and phospholipase Cγ2 (PLCγ2) phosphorylation, leading to increased nuclear translocation of NFATc1. The heterozygous cherubism mutation exacerbates bone loss with increased osteoclast formation in a mouse calvarial TNF‐α injection model as well as in a human TNF‐α transgenic mouse model (hTNFtg). SH3BP2 knockdown in RAW264.7 cells results in decreased TRAP‐positive multinucleated cell formation. These findings suggest that the SH3BP2 cherubism mutation can cause jawbone destruction by promoting osteoclast formation in response to TNF‐α expressed in cherubism lesions and that SH3BP2 is a key regulator for TNF‐α–induced osteoclastogenesis. Inhibition of SH3BP2 expression in osteoclast progenitors could be a potential strategy for the treatment of bone loss in cherubism as well as in other inflammatory bone disorders. © 2014 American Society for Bone and Mineral Research.     

Environmental Toxicology: Polychlorinated Biphenyls Impair TNF‐α Release In Vitro

Tumour necrosis factor (TNF‐α) was induced by bacterial lipopolysaccharides (LPS)/phytohemagglutin (PHA) stimulated human whole blood in vitro. Levels of TNF‐α were evaluated by enzyme‐linked immunosorbent assay. Blood samples treated with polychlorinated biphenyls (PCB 77, PCB 126) exhibited impairment of TNF‐α release: 50 pg/μl PCB reduced by up to 66% and 500 pg/μl PCB reduced by up to 93% the TNF‐α release compared with the controls.     

Effects of caveolin-1 and P-ERK1/2 on Ang II-induced glomerular mesangial cell proliferation

Abstract

This study explored the effects of caveolin-1, p-ERK1/2 and transient receptor potential channel 6 (TRPC6) on angiotensin II (Ang II)-induced glomerular mesangial cell (GMC) proliferation, and investigated the role of Ang II on GMC proliferation. GMC cultures were divided into Control, Ang II (Ang II 10^?7?mol/L), PD98059 (Ang II 10^?7?mol/L?+?PD98059 5?×?10^?5?mol/L) and MβCD groups (Ang II 10^?7?mol/L?+?MβCD 10^?2?mol/L). GMCs proliferation was measured by the methyl thiazolil tetracolium and trypan blue assays. The distribution of caveolin-1, p-ERK1/2 and TRPC6 was monitored by immunocytochemistry. Real time polymerase chain reaction (PCR) was used to assess mRNA expression of caveolin-1 and TRPC6. Western blot analysis was used to assess protein expression of caveolin-1, p-ERK1/2 and TRPC6. The results showed that Ang II promoted GMC proliferation. PD98059 and MβCD blocked Ang II-induced GMC proliferation, by 31.06% and 48.96%, respectively. In comparison with the control group, the expression of p-ERK1/2 and TRPC6 was significantly higher and caveolin-1 expression was significantly lower in the Ang II group. PD98059 markedly decreased p-ERK1/2 and TRPC6 expression and increased caveolin-1 expression. MβCD decreased the expression of p-ERK1/2 and TRPC6, but had no significant effect on caveolin-1 protein expression. These findings suggested that the intact caveolae structure was associated with Ang II-induced GMC proliferation, ERK1/2 activation and TRPC6 expression. And p-ERK1/2 acted as an upstream signal molecule for TRPC6. Moreover, p-ERK1/2 and caveolin-1 appeared to be inhibited reciprocally, thus regulated GMC proliferation by regulating TRPC6 expression.     

Response to tumor necrosis factor‐α mediated inflammation involving activation of prostaglandin E2 and Wnt signaling in nucleus pulposus cells

The cyclooxygenase 2 (COX‐2) product, prostaglandin E₂ (PGE₂), acts through a family of G protein‐coupled receptors designated E‐prostanoid (EP) receptors that mediate intracellular signaling by multiple pathways. However, it is not known whether crosstalk between tumor necrosis factor‐α(TNF‐α)–PGE₂‐mediated signaling and Wnt signaling plays a role in the regulation of intervertebral disc (IVD) cells. In this study, we investigated the relationship between TNF‐α–PGE₂ signaling and Wnt signaling in IVD cells. TNF‐α increased the expression of COX‐2 in IVD cells. The EP receptors EP1, EP3, and EP4 were expressed in IVD cells, and TNF‐α significantly increased PGE₂ production. Stimulation with TNF‐α also upregulated EP3 and EP4 mRNA and protein expression in IVD cells. The inductive effect of the EP3 and EP4 receptors on Topflash promoter activity was confirmed through gain‐ and loss‐of‐function studies using selective EP agonists and antagonists. PGE₂ treatment activated Wnt–β‐catenin signaling through activation of EP3. We conclude that TNF‐α‐induced COX‐2 and PGE₂ stimulate Wnt signaling and activate Wnt target genes. Suppression of the EP3 receptor via TNF‐α–PGE₂ signaling seems to suppress IVD degeneration by controlling the activation of Wnt signaling. These findings may help identify the underlying mechanism and role of Wnt signaling in IVD degeneration. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1756–1768, 2015.     

Serine/threonine kinase, Cot/Tpl2, regulates renal cell apoptosis in ischaemia/reperfusion injury

Aim: Cot/Tpl2, a serine/threonine (Ser/Thr) protein kinase, has been classified as a member of the mitogen‐activated protein kinase (MAPK) family, and is known to have a pleiotropic role. Many studies have reported the involvement of Cot/Tpl2, mainly as a member of the Toll‐like receptor (TLR) 4 signalling pathway in lipopolysaccharide (LPS)‐induced tumor necrosis factor‐α (TNF‐α) production. At the same time, it is also related to the caspase‐dependent apoptotic pathway. Thus, the role of Cot/Tpl2 in ischaemia/reperfusion injury (IRI) in which TNF‐α and apoptosis are the major pathogenetic factors was studied. Methods: IRI was induced in wild type (Cot/Tpl2^+/+) mice and in Cot/Tpl2‐deficient (Cot/Tpl2^?/?) mice. The extent of tubular injury and renal function were studied. TNF‐α production, neutrophil infiltration and apoptosis were also compared between the two groups. Results: Cot/Tpl2^?/? mice had preserved renal function compared with wild type mice in IRI. Although Cot/Tpl2 was phosphorylated in IRI and in the cultured tubular epithelial cells (TEC) after stimulation with LPS and hydrogen peroxide, there were no significant differences in terms of TNF‐α production, neutrophil infiltration or MAPK activation between Cot/Tpl2^+/+ and Cot/Tpl2^?/? mice. In contrast, Cot/Tpl2^?/? mice showed obviously reduced terminal deoxynucleotidyl transferase‐mediated dUTP nick end labelling positive cells and cleaved caspase‐3 positive cells. Furthermore, Cot/Tpl2‐deficient TECs demonstrated significantly less caspase‐3 activation after hydrogen peroxide stimulation with comparable caspase‐9 activation to wild type TEC. Conclusion: Cot/Tpl2 did not function as a member of MAPK family, but as a promoter of apoptosis in IRI. These results suggest that Cot/Tpl2 could be a possible therapeutic target in IRI.     

TNF‐α–induced NF‐κB signaling reverses age‐related declines in VEGF induction and angiogenic activity in intervertebral disc tissues

We previously demonstrated that VEGF and its receptors were expressed in human herniated discs (HD). TNF‐α induced VEGF, resulting in neovascularization of disc tissues in a model of HD. The goal of the current research was to investigate the precise role of TNF‐α–induced VEGF and the mechanism of angiogenesis in disc tissues. We performed ELISAs, Western blots, and immunohistological examinations to assess the role of TNF‐α–induced VEGF using organ disc cultures with wild type, TNF receptor 1‐null (TNF‐RI^null), or TNF receptor 2‐null (TNF‐RII^null) mice. VEGF induction was inhibited when we used TNF‐RI^null‐derived disc tissues. NF‐κB pathway inhibitors also strongly suppressed VEGF induction. Thus, TNF‐α induced VEGF expression in disc cells primarily through the NF‐κB pathway. In addition, VEGF immunoreactivity was detected predominantly in annulus fibrosus cells and increased after TNF‐α stimulation. TNF‐α treatment also resulted in CD31 expression on endothelial cells and formation of an anastomosing network. In contrast, angiogenic activity was strongly inhibited in the presence of NF‐κB inhibitors or anti‐VEGF antibody. Our data show angiogenesis activity in disc tissues is regulated by VEGF and the NF‐κB pathway, both of which are induced by TNF‐α. The level of angiogenic activity in disc tissues was closely related to aging. Because neovascularization of HD is indispensable for HD resorption, the prognosis of HD and the rate of the resorption process in patients may vary as a function of the patient's age. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:229–235, 2009     

Assessment of ischaemia–reperfusion injury in the mice testis by using contrast ultrasound molecular imaging

Timely diagnosis of ischaemia–reperfusion (IR)‐induced injury after testicular torsion may be critical for saving reproductive function. The purpose of this study was to detect IR‐induced injury, indicated by E‐selectin overexpression, in murine testis using ultrasound molecular contrast imaging. Mice underwent 720^° unilateral testicular torsion (ischaemia) followed by detorsion (reperfusion), and the control group (Sham‐IR) was operated identically without extended ischaemia. In a separate positive control group, TNF‐α was injected intratesticularly to induce inflammation and compared to intratesticular saline injection. Selectin‐targeted or nontargeted ultrasound contrast microbubbles were injected intravenously, and two‐dimensional (2D) real‐time high‐resolution ultrasound testicular imaging was performed after reperfusion or after TNF‐α injection. Contrast intensity levels were significantly higher in the testis of the IR group as compared to the Sham‐IR group after injection of targeted contrast microbubbles. Contrast intensities were similar between the IR and Sham‐IR groups after injection of nontargeted microbubbles. In addition, targeted contrast intensity levels were significantly higher in the TNF‐α‐treated group as compared to the control group. This study indicates that ultrasound contrast molecular imaging with microbubbles targeted to E‐selectin can be used to assess IR‐induced testicular injury.     

Severe gunshot injuries in a porcine model: impact on central markers of innate immunity

Background: The mechanisms behind lipopolysaccharide (LPS) tolerance remain obscure. LPS signals through Toll‐like receptor 4 (TLR4) and severe trauma/haemorrhage may influence binding and signalling through this receptor, e.g. by changing membrane expression or by releasing endogenous ligands like High Mobility Group Box 1 (HMGB1). The aim of this study was to examine these relations further in a porcine model with standardized trauma. Methods: Nine anaesthetized pigs sustained one gunshot through the femur and one pistol shot through the upper abdomen. Blood was sampled before and 90 min after shooting. The samples were stimulated for 4 h with LPS 10 ng/ml or an equivalent amount of normal saline. The leucocyte response was evaluated by measuring the tumour necrosis factor‐α (TNF‐α) and CXC ligand 8 (CXCL8) in the supernatant. Flow cytometry was used to measure the surface expression of TLR4 on CD14+ monocytes. HMGB1 concentrations were measured in the plasma. Results: Trauma and treatment caused a significant decline in the LPS‐stimulated concentrations of TNF‐α [4.53 ± 0.24 pg/ml (ln) at 0 min, 3.54 ± 0.35 pg/ml (ln) at 90 min, P=0.026], but did not modify the release of CXCL8. Monocyte TLR4 expression was unchanged. Plasma HMGB1 increased significantly [<0.92 vs. 3.02 ± 0.19 ng/ml (ln), P<0.001]. The concentrations of TNF‐α and CXCL8 did not correlate with TLR4 expression or HMGB1 concentrations. Conclusion: The results suggest that trauma‐induced LPS tolerance is not primarily regulated by TLR4 expression on circulating CD14+ monocytes or by the release of HMGB1 from damaged tissues.     

NADPH氧化酶介导血管紧张素Ⅱ诱导的腹膜间皮细胞转分化及细胞外基质积聚

目的 探讨NADPH氧化酶在血管紧张素(Ang)Ⅱ诱导的腹膜间皮细胞转分化以及细胞外基质积聚中的作用。 方法 体外培养SD大鼠原代腹膜间皮细胞，静止24 h后，随机分为以下4组：正常对照组，AngⅡ（10^-7 mol/L）组，AngⅡ+ Los(洛沙坦,10 μmol/L)组及AngⅡ+DPI（NADPH氧化酶活性抑制剂，10 μmol/L）组。应用荧光染料（DCF）及激光共聚焦显微镜检测细胞内活性氧（ROS）的产生。RT-PCR检测NADPH氧化酶亚单位p47phox以及纤溶酶原激活物抑制剂（PAI）1、α平滑肌肌动蛋白（SMA）、E钙黏蛋白（cadherin） mRNA的表达。Western印迹检测p47phox、α-SMA的蛋白表达。 结果 （1）外源性AngⅡ可显著增加大鼠腹膜间皮细胞ROS的产生，刺激15 min后，ROS 的表达较对照组上升了(3.64±0.53)倍。DPI和洛沙坦可显著抑制AngⅡ刺激后ROS的产生（P < 0.05）。（2）AngⅡ刺激腹膜间皮细胞后， NADPH氧化酶亚单位p47phox mRNA和蛋白的表达均呈上升趋势。洛沙坦和DPI可阻断由AngⅡ诱导的p47phox表达上调（P < 0.05）。（3） AngⅡ诱导α-SMA表达的上调以及 E-cadherin mRNA的下调, 洛沙坦和DPI可部分逆转AngⅡ的这种作用。（4）AngⅡ刺激8 h后可明显上调PAI-1的mRNA表达，为正常对照组的（3.06±0.77）倍。 洛沙坦和DPI可明显阻断PAI-1的表达上调（P < 0.05）。 结论 NADPH氧化酶依赖产生的ROS介导了AngⅡ诱导的腹膜间皮细胞转分化及细胞外基质积聚。阻断AngⅡ的作用及抑制NADPH氧化酶的表达和活性可作为防治腹膜纤维化的潜在治疗靶点。     

Plasma and Urinary Cytokine Homeostasis and Renal Dysfunction during Cardiac Surgery

Background: Cardiac surgery induces changes in plasma cytokines. Proinflammatory cytokines have been associated with a number of renal diseases. The proinflammatory cytokines interleukin 8 (IL-8), tumor necrosis factor [alpha] (TNF[alpha]), and interleukin 1[beta] (IL-1[beta]) are smaller than the antiinflammatory cytokines interleukin 10 (IL-10), interleukin 1 receptor antagonist (IL-1ra), and TNF soluble receptor 2 (TNFsr2), and thus undergo glomerular filtration more readily. Accordingly, this study investigated the relation between plasma and urinary cytokines and proximal renal dysfunction during cardiac surgery.

Methods: Twenty patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (CPB) were studied. Blood and urine samples were analyzed for proinflammatory and antiinflammatory cytokines. Proximal tubular dysfunction was measured using urinary N-acetyl-[beta]-d-glucosaminidase (NAG)/creatinine and [alpha]1-microglobulin/creatinine ratios.

Results: Plasma IL-8, IL-10, IL-1ra, and TNFsr2 values were significantly elevated compared with baseline. Urinary IL-1ra and TNFsr2 were significantly elevated. Urinary NAG/creatinine and [alpha]1-microglobulin/creatinine ratios were also elevated. Plasma TNF[alpha] at 2 h correlated with urinary NAG/creatinine ratio at 2 and 6 h (P < 0.05) and with urinary IL-1ra at 2 h (P < 0.05). Plasma IL-8 at 2 h correlated with NAG/creatinine at 6 h (P < 0.05). Urinary IL-1ra correlated with urinary NAG/creatinine ratio after cross-clamp release and 2 and 6 h after CPB (P < 0.05).     

Osteocyte apoptosis is mechanically regulated and induces angiogenesis in vitro

Osteocyte apoptosis, associated with reduced interstitial fluid flow, precedes osteoclast precursor recruitment and may aid in the delivery of osteoclast precursors to the remodeling site by promoting angiogenesis. To test the association between fluid flow and osteocyte apoptosis, osteocyte‐like MLO‐Y4 cells were subjected to either oscillatory fluid flow (10 dynes/cm², 1 Hz) or no flow conditions with or without TNF‐α treatment to induce osteocyte apoptosis chemically. Flow protected osteocytes from apoptosis regardless of whether they were treated with TNF‐α (p < 0.001) or not (p < 0.05). TNF‐α‐induced apoptotic and nonapoptotic osteocyte conditioned media were used to study the effect of osteocyte apoptosis on angiogenesis. Apoptotic osteocyte conditioned media caused more endothelial cell proliferation (p < 0.05) and migration (p < 0.05), and tubule networks with longer (p < 0.01) and more (p < 0.001) branches than nonapoptotic osteocyte conditioned media. Apoptotic osteocyte conditioned media contained more vascular endothelial growth factor (VEGF) than nonapoptotic osteocyte conditioned media (p < 0.05). VEGF concentrations found in apoptotic osteocyte conditioned media formed endothelial tubule networks with longer (p < 0.05) and more (p < 0.02) branches than VEGF concentrations in nonapoptotic osteocyte conditioned media. Blocking VEGF in apoptotic osteocyte conditioned media abolished tubule formation effects (p < 0.001). Our results suggest that osteocyte apoptosis is flow‐regulated and promotes angiogenesis in a VEGF‐mediated manner. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:523–530, 2011     

Differential leucocyte detection by flow cytometry improves the diagnosis of genital tract inflammation and identifies macrophages as proinflammatory cytokine‐producing cells in human semen

Genital tract inflammation is considered as a major cause of male infertility with leucocytospermia as widely used diagnostic marker. However, threshold of 10⁶ leucocytes ml^?1 recommended by the WHO is a matter of debate. Moreover, leucocyte subpopulations and their impact cannot be identified by the routine peroxidase method (POM). Ejaculates of subfertile men (n = 47) were analysed by flow cytometry (FACS) using a bead‐based method. Leucocytes were identified by CD18 and further divided into macrophages (HLA‐Dr+/CD66abce‐) and neutrophils (HLA‐Dr‐/CD66abce+). IL‐1β, TNF‐α and IL‐6 production was investigated in these subpopulations. It was found that CD18‐positive cells correlated significantly with POM. However, only in samples with POM below 10⁶ per millilitre, FACS detected significantly higher leucocyte numbers. Moreover, in 31% of these samples, FACS leucocyte detection reached threshold values greater than 1 × 10⁶ ml^?1, fulfilling the criteria for diagnosis of leucocytospermia. Neutrophils were the predominating leucocyte population. Nevertheless, in 24% of samples, macrophages encountered more than 50% of leucocytes. Most interestingly, only macrophages produced significant amounts of IL‐1β, TNF‐α and IL‐6. It is concluded that FACS improves detection and functional differentiation of seminal leucocytes as one of the diagnostic hallmarks of male genital tract inflammation.     

Combined interleukin 1 and tumour necrosis factor α blockade in rat crescentic anti-glomerular basement membrane glomerulonephritis

SUMMARY: Studies in experimental models have established that blockade of either interleukin 1 (IL‐1) or tumour necrosis factor α (TNF‐α) is effective in suppressing crescentic glomerulonephritis. However, it is not known whether simultaneous blockade of both cytokines will provide additional disease suppression compared with that produced by single cytokine blockade. We have addressed this question in a study of accelerated crescentic anti‐glomerular basement membrane (GBM) glomerulonephritis in the rat. Groups of six animals were treated with an IL‐1 receptor antagonist (IL‐1ra), TNF‐α‐binding protein (TNFbp), IL‐1ra + TNFbp (combined) or saline (control) from the time of anti‐GBM serum injection until being killed, 10 days later. Saline‐treated animals developed crescentic glomerulonephritis with tubulointerstitial damage, heavy proteinuria and renal impairment. Compared with saline, treatment with either IL‐1ra or TNFbp alone resulted in significant suppression of crescent formation (3.0% and 3.3%, respectively, vs. 21.0%; both P < 0.001 vs. control), tubulointerstitial leucocytic infiltration (262 ± 31 and 282 ± 32 cells/mm² vs. 481 ± 71 cells/mm²; both P < 0.001 vs. control) and proteinuria (167 ± 44 and 164 ± 23 mg/24 h vs. 279 ± 36 mg/24 h; both P < 0.001 vs. control) and prevented the loss of renal function. Combined IL‐1ra and TNFbp treatment resulted in a virtually identical degree of disease suppression as individual cytokine blockade in terms of crescent formation (2.7%), interstitial leucocytic infiltration (274 ± 45 cells/mm²), proteinuria (190 ± 18 mg/24 h) and renal function preservation. In conclusion, this study has demonstrated that blockade of either IL‐1 or TNF‐α alone substantial suppresses experimental crescentic glomerulonephritis to a similar extent to that achieved by simultaneous blockade of both cytokines. These findings provide a rationale for the use of cytokine monotherapy, rather than multiple cytokine blockade, in the treatment of human crescentic glomerulonephritis.     

Relationships between tumour necrosis factor-α, interleukin-12B and interleukin-10 gene polymorphisms and hepatitis B in Chinese Han haemodialysis patients

Aim: To investigate the possible association of gene polymorphisms of tumour necrosis factor (TNF)‐α (‐238 and ‐308), interleukin (IL)‐10 (‐592 and ‐819) and 3′ untranslated region (3′UTR) of the IL12B (‐1188) and hepatitis B in Chinese Han haemodialysis (HD) patients. Methods: The genotyping of TNF‐α ‐238 and ‐308, IL‐10 ‐592 and ‐819 and 3′UTR of the IL12B were performed by polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) method. Results: The TNF‐α‐238 A allele, the IL12B 3′UTR C/C, C/A genotypes were associated with decreased susceptibility to hepatitis B viral infection (P = 0.047, P= 0.003 and P = 0.001 respectively). The frequencies of IL‐10–592 A/A genotype, IL‐10–819 T/T genotype were lower in the HBV persistence group (P = 0.029 and P = 0.019) than those in the virus clearance group. Conclusions: TNF‐α and IL12B 3′UTR gene polymorphisms may be associated with HBV susceptibility and IL‐10 gene polymorphisms may be related to the HBV persistence infection in Chinese Han HD patients.     

Plasma and urinary cytokine homeostasis and renal dysfunction during cardiac surgery

BACKGROUND: Cardiac surgery induces changes in plasma cytokines. Proinflammatory cytokines have been associated with a number of renal diseases. The proinflammatory cytokines interleukin 8 (IL-8), tumor necrosis factor alpha (TNFalpha), and interleukin 1beta (IL-1beta) are smaller than the antiinflammatory cytokines interleukin 10 (IL-10), interleukin 1 receptor antagonist (IL-1ra), and TNF soluble receptor 2 (TNFsr2), and thus undergo glomerular filtration more readily. Accordingly, this study investigated the relation between plasma and urinary cytokines and proximal renal dysfunction during cardiac surgery. METHODS: Twenty patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (CPB) were studied. Blood and urine samples were analyzed for proinflammatory and antiinflammatory cytokines. Proximal tubular dysfunction was measured using urinary N-acetyl-beta-d-glucosaminidase (NAG)/creatinine and alpha1-microglobulin/creatinine ratios. RESULTS: Plasma IL-8, IL-10, IL-1ra, and TNFsr2 values were significantly elevated compared with baseline. Urinary IL-1ra and TNFsr2 were significantly elevated. Urinary NAG/creatinine and alpha1-microglobulin/creatinine ratios were also elevated. Plasma TNFalpha at 2 h correlated with urinary NAG/creatinine ratio at 2 and 6 h (P < 0.05) and with urinary IL-1ra at 2 h (P < 0.05). Plasma IL-8 at 2 h correlated with NAG/creatinine at 6 h (P < 0.05). Urinary IL-1ra correlated with urinary NAG/creatinine ratio after cross-clamp release and 2 and 6 h after CPB (P < 0.05). CONCLUSIONS: Cardiac surgery using CPB leads to changes in plasma and urinary cytokine homeostasis that correlate with renal proximal tubular dysfunction. This dysfunction may be related to the renal filtration of proinflammatory mediators. Renal autoprotective mechanisms may involve the intrarenal generation of antiinflammatory cytokines.     

Acceleration of superoxide production from leukocytes in trauma patients.

Superoxide (O2-) and granulocyte elastase (GE) from neutrophils mediate host defense and tissue injury in inflammation. To determine alterations in leukocyte function after trauma, O2- production and GE secretion from neutrophils were studied in trauma patients (n = 20) and healthy controls (n = 15). The priming effect of tumor necrosis factor (TNF), interleukin-1 alpha (IL-1 alpha), and lipopolysaccharide (LPS) on O2- or GE release also was evaluated. Superoxide production (nmole/10 minutes) was elevated significantly in trauma patients at days 0 (9.5 +/- 4.8), 1 (14.2 +/- 7.3), and 3 (12.2 +/- 5.9) and returned to control levels (4.2 +/- 1.6) by day 7. There was no difference in GE secretion between trauma patients and healthy controls. Incubation of neutrophils with TNF induced release of both O2- and GE. Superoxide production was induced by TNF at concentrations at or greater than 10(-11) mol/L. Granulocyte elastase secretion was induced in a time- and dose-dependent manner by TNF at concentrations between 10(-10) and 10(-7) mol/L. In contrast IL-1 alpha and LPS did not potentiate O2- or GE release. These results suggest that neutrophil O2- production increases acutely in trauma. Tumor necrosis factor may mediate this O2- and GE production by neutrophils involved in the inflammatory response.