百草枯中毒患者的IL-6、sIL-6R、sgp130水平及其与患者预后的相关性分析

目的 探讨百草枯中毒患者的IL-6、sIL-6R、sgp130表达水平及其与患者预后的关系.方法 选取2017年1月至2019年7月我院收治的百草枯中毒患者60例作为中毒组,选择同期来我院进行健康体检的志愿者60名为对照组.根据患者的预后情况将中毒组患者分为预后良好组(38例)和预后不良组(22例).比较中毒组患者和对...     

Serum levels of soluble interleukin 6 receptor and soluble gp130 are elevated in patients with localized scleroderma

OBJECTIVE: To investigate the clinical relevance of serum soluble interleukin 6 receptor (sIL-6R) and soluble gp130 (sgp130) in localized scleroderma. METHODS: Serum levels of sIL-6R and sgp130 were examined by ELISA in 45 patients with localized scleroderma. Twenty patients with systemic sclerosis (SSc) and 20 healthy individuals served as controls. RESULTS: Serum levels of both sIL-6R and sgp130 were significantly elevated in patients with localized scleroderma compared with healthy controls. Moreover, serum sgp130 levels in patients with localized scleroderma were significantly higher than in patients with SSc. In patients with localized scleroderma, elevated sIL-6R levels significantly correlated with levels of IgM antihistone antibodies, the presence of rheumatoid factor, the number of linear lesions, and the number of body areas involved. Elevated sgp130 levels were significantly associated with levels of IgG antihistone antibodies, the number of plaque lesions, the total number of lesions, and the number of body areas involved. CONCLUSION: These results suggest that elevated serum sIL-6R and sgp 30 may reflect activation of the IL-6 system that may be associated with the development of sclerotic lesions and autoantibody production in localized scleroderma.     

Enhanced production of interleukin-6 (IL-6), oncostatin M and soluble IL-6 receptor by cultured peripheral blood mononuclear cells from patients with systemic sclerosis.

OBJECTIVES: To determine whether the spontaneous production of interleukin 6 (IL-6), oncostatin M (OSM), soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130) from peripheral blood mononuclear cells (PBMC) is increased in patients with systemic sclerosis (SSc). METHODS: The culture supernatants of PBMC from patients with SSc (n = 33) and healthy controls (n = 20) were examined by enzyme-linked immunosorbent assay. RESULTS: The production levels of IL-6, OSM and sIL-6R were significantly higher in patients with SSc than in controls. However, sgp130 levels in supernatants from patients with SSc were not significantly elevated when compared with those from controls. Soluble IL-6R levels correlated significantly with the severity of pulmonary fibrosis in patients with SSc. CONCLUSIONS: The enhanced production of IL-6, OSM and sIL-6R from PBMC may cooperatively contribute to the disease process in SSc. In particular, enhanced sIL-6R production from PBMC may be related to the development of pulmonary fibrosis via enhancement of IL-6 signal transduction in SSc, since sIL-6R can act as an agonist of IL-6.     

Influence of humanized anti-IL-6R antibody, tocilizumab on the activity of soluble gp130, natural inhibitor of IL-6 signaling

Tocilizumab, humanized anti-IL-6R antibody is a novel anti-rheumatic drug. In the present study, we examined the influence of tocilizumab on the inhibitory activity of soluble gp130 (sgp130) against IL-6 signaling. BAF-h130 cells, human gp130 transfected mouse pro-B cell line, were cultured with the mixture with IL-6, sIL-6R and sgp130 for 72 h. BAF-h130 cells proliferated by the addition of both IL-6 and sIL-6R, but not IL-6 or sIL-6R alone. The proliferation induced by IL-6/sIL-6R complex was inhibited by sgp130 concentration-dependently. Tocilizumab inhibited IL-6/sIL-6R-induced cell proliferation. On the other hand, it did not affect the suppressive property of sgp130. To examine if tocilizumab can dissociate IL-6/sIL-6R/sgp130 complex, we established an ELISA system to detect IL-6/sIL-6R/sgp130 complex using anti-IL-6R coated ELISA plate. The results clearly indicated that ELISA system established was detectable IL-6/sIL-6R/sgp130 complex in a concentration dependent manner. Tocilizumab was added to IL-6/sIL-6R/sgp130 complex-fixed plate and then remaining IL-6/sIL-6R/sgp130 complexes on the plate were measured. The amount of IL-6/sIL-6R/sgp130 complexes on the plate was not changed by the addition of tocilizumab. In conclusion, tocilizumab exerts its inhibitory effect through the inhibition of IL-6R directly without affecting natural inhibitor sgp130.     

Profile of soluble cytokine receptors in Crohn's disease

INTRODUCTION: Soluble cytokine receptors (sCRs) modulate the in vivo activity of cytokines. Deficient sCR production could participate in the pathogenesis and course of Crohn's disease (CD). The aim of the study was to examine the profile of sCRs in CD patients and their modulation by infliximab and corticosteroids. METHODS: We prospectively examined active CD patients (aCD) treated with either infliximab (n = 21) or corticosteroids (n = 9), CD patients in clinical remission (rCD, n = 20), ulcerative colitis patients (UC, n = 24), and healthy subjects (HS, n = 15). Cultures of colonic biopsies were also examined from CD inflamed (n = 8), CD non-inflamed (n = 7), and healthy mucosa (n = 8). Levels of tumour necrosis factor alpha (TNF-alpha), soluble TNF receptor I (sTNFRI), soluble TNF receptor II (sTNFRII), interleukin 1beta (IL-1beta), soluble IL-1 receptor I (sIL-1RI), soluble IL-1 receptor II (sIL-1RII), IL-6, soluble IL-6 receptor (sIL-6R), and sgp130 were measured using ELISA. RESULTS: Higher levels of sTNFRI (p<0.05, p<0.01), sTNFRII (p<0.01, p<0.01), sIL-1RI (p<0.05, NS), IL-6 (p<0.01, p<0.01), and sIL-6R (p<0.05, NS) were observed in aCD compared with rCD and HS. Interestingly, sIL-1RII (p<0.05, p<0.01) and sgp130 (p<0.01, p<0.01) were profoundly decreased in aCD compared with rCD and HS, and were negatively correlated with CRP. Deficient production of sIL-1RII was specific to CD (not observed in ulcerative colitis), and was further confirmed at the mucosal level. Infliximab decreased sTNFRII at one and four weeks (p<0.05) and enhanced sIL-6R levels at one week (p<0.05). Corticosteroids increased sIL-1RII levels at one week (p<0.05). CONCLUSION: CD is associated with dysregulated production of sCRs. Deficiency in sIL-1RII and sgp130 may be essential to CD pathogenesis. Their replacement through the use of fusion proteins could represent future alternative therapeutic strategies for CD.     

可溶性糖蛋白130与稳定型冠心病患者冠状动脉粥样硬化严重程度之间关系

目的: 评估稳定型冠状动脉疾病（stable coronary artery disease, CAD）患者血清白细胞介素-6（IL-6）、可溶性IL-6受体（sIL-6R）和可溶性糖蛋白130（sgp130）浓度及与冠状动脉粥样硬化严重程度间的关系。方法：纳入2017年1月到2019年1月间于惠州市第六人民医院心内科具有动脉造影适应症疑似冠心病患者89例,根据冠状动脉造影结果将患者分成两组：存在冠状动脉粥样斑块CAD组,即粥样斑块组,共64例;不存在冠状动脉粥样斑块CAD组,即非粥样斑块组,共25例。采用ELISA法检测两组患者血清IL-6、sIL-6R和sgp130浓度,Spearman相关分析sgp130浓度与受累冠脉数目及Gensini评分的相关性,多因素logistic回归分析冠状动脉粥样硬化斑块病变的预测因子。结果： 粥样斑块组与非粥样斑块组在年龄、BMI、高血压、糖尿病、血脂参数上无统计学差异（P>0.05）, 粥样斑块组患者男性吸烟者居多（P<0.05）。粥样斑块组血清sgp130浓度显著低于非粥样斑块组（314.97±84.39 VS 399.08±79.99 ng/ml, P<0.001）,粥样斑块组血清IL-6浓度显著高于非粥样斑块组（P<0.05）, 粥样斑块组血清sIL-6R浓度和C-反应蛋白浓度(CRP)与非粥样斑块组比较差异无统计学意义。多因素logistic回归分析示血清sgp130浓度是冠状动脉粥样硬化斑块病变存在的预测因子（P=0.018）。血清sgp130浓度与受累冠状动脉数目间呈负相关（r=-0.310,P=0.007）,Gensini评分指数与血清sgp130浓度呈负相关（r=-0.410, P=0.001）,稳定型CAD患者sgp130浓度是Gensini评分指数独立危险因素。结论：稳定型CAD患者血清sgp130浓度与冠状动脉损伤严重程度呈负相关,血清sgp130水平是冠状动脉粥样硬化严重程度血清标志物。     

慢性肝病患者血清可溶性白细胞介素—6受体及其β链的检测及意义

目的 观察慢性肝病患者血清可溶性自介素－６受体（ｓｏｌｕｂｌｅ ｉｎｔｅｅｒｌｅｕｋｉｎ－６ ｒｅｃｐｔｏｒ,ｓＩＬ－６Ｒ）和可溶性ＩＬ－６受体β链（ｓｇｐ１３０）的变化。方法 应用酶联免疫吸附法检测慢性肝炎患者４０例,肝炎后肝硬化患者１５例和３５例健康对照者血清中ｓＩＬ－６Ｒ、ｓｇｐ１３０水平。结果 慢性肝炎患者血清ｓＩＬ－６ｒ、ｓｐｇ１３０含量（μｇ／Ｌ）分别为２２４．２７和４８９．３５均显著     

Circulating interleukin-6 family cytokines and their receptors in patients with congestive heart failure

gp130 is a common signal-transducing receptor subunit for the interleukin (IL)-6 cytokine family. Studies in genetically engineered animal models have demonstrated a critical role for the gp130-dependent cardiomyocyte survival pathway in the transition to heart failure. In the present study, we examined plasma levels of the IL-6 family of cytokines and the soluble form of their receptors in patients with congestive heart failure (CHF). Circulating levels of the IL-6 family of cytokines, soluble IL-6 receptor (sIL-6R), and soluble gp130 (sgp130) were examined in 48 patients with various degrees of CHF, including dilated cardiomyopathy (DCM), ischemic cardiomyopathy (ICM), and valvular cardiomyopathy (VCM). Circulating levels of IL-6, leukemia inhibitory factor (LIF), and sgp130 significantly increased in association with the severity of CHF. No significant difference was observed in the circulating levels of sIL-6R and IL-11 among these patients. Interestingly, DCM patients showed higher circulating sgp130 levels than patients with ICM or VCM. Our findings suggest that gp130 expression in the heart is likely to be dynamic, and that the IL-6 family of cytokines and their common receptor gp130 participates in the pathogenesis of CHF, especially in DCM.     

Serum interleukin-6, soluble interleukin-6 receptor and soluble gp130 exhibit different patterns of age- and menopause-related changes

Growing evidence suggests that interleukin-6 (IL-6) may play a pathogenetic role in postmenopausal bone loss and in other age-related pathological conditions. In this study, we have examined the age-related changes in the serum levels of IL-6 and the soluble receptors that modulate its biological activity--soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130)--in 220 women (from 25 to 104yr old), including 22 centenarians. Serum IL-6 rose exponentially with age (r=0.74, p<0.0001). The median level of IL-6 increased almost ten-fold with age, from 1.16pg/ml in premenopausal women to 10.27pg/ml in centenarians. Serum sIL-6R and sgp130 showed an increase until the seventh decade and a progressive decrease in older ages (r=0.39, p<0.0001 and r=0.26, p=0.008, respectively). IL-6, sIL-6R and sgp130 were significantly higher in women within 10yr of menopause as compared to premenopausal subjects (1.51 vs. 1.16pg/ml, p=0.012; 41.9 vs. 35.7ng/ml, p=0.002; and 253.4 vs. 230.7ng/ml, p=0.008, respectively). In postmenopausal women, a negative correlation was found between sIL-6R and the lumbar bone mineral density (BMD) (r=-0.28, p=0.002) even after adjusting for age and weight. Furthermore, sIL-6R levels were higher in osteoporotic compared to normal women (47.9 vs. 39.5ng/ml, p=0.001). In conclusion, our results show that the serum levels of IL-6, sIL-6R and sgp130 exhibit different patterns of age- and menopause-related changes, and that the biological activity of IL-6 may be increased with age with potential implications in the age-related diseases such as osteoporosis.     

Plasma levels of soluble glycoprotein 130 in acute myocardial infarction

OBJECTIVES: Soluble glycoprotein 130 (sgp130), a circulating form of receptor subunit for the interleukin (IL) -6 cytokine family, modulates the biological actions of its ligands as an inhibitory regulator. The role of sgpl30 in cardiovascular diseases such as acute coronary syndrome remains unknown. METHODS: Plasma levels of sgp130 were examined by enzyme-linked immunosorbent assay in 33 patients with acute myocardial infarction (AMI; mean age 67 +/- 2 years, 21 males and 12 females), who were admitted to our hospital within 24 hr of onset of AMI and survived for 4 weeks. RESULTS: Plasma sgp130 levels were significantly higher at admission (260.5 +/- 7.3 ng/ml), and were significantly lower from day 2 to day 5 (202.4 +/- 5.1 ng/ml at day 3) as compared with normal control subjects (n = 38, 227.1 +/- 5.6 ng/ml). The lowest sgp130 levels inversely correlated with white blood cell count at admission (r = -0.42, p < 0.05) and with peak C-reactive protein levels (r = -0.43, p < 0.05). Additional in vitro study revealed that incubation of AMI plasma with exogenous IL-6 plus soluble IL-6 receptor resulted in a decrease in plasma sgp130 levels, suggesting the possible reason for reduced plasma sgp130 levels in AMI. CONCLUSIONS: The present study indicates that plasma sgp130 levels were modulated during the time course of AMI and inversely associated with inflammation in AMI.     

Evaluation of interleukin-6 and its soluble receptor components sIL-6R and sgp130 as markers of inflammation in inflammatory bowel diseases

Purpose

Interleukin-6 (IL-6) production and signalling are increased in the inflamed mucosa in inflammatory bowel diseases (IBD). As published serum levels of IL-6 and its soluble receptors sIL-6R and sgp130 in IBD are from small cohorts and partly contradictory, we systematically evaluated IL-6, sIL-6R and sgp130 levels as markers of disease activity in Crohn’s disease (CD) and ulcerative colitis (UC).

Methods

Consecutive adult outpatients with confirmed CD or UC were included, and their disease activity and medication were monitored. Serum from 212 CD patients (815 measurements) and 166 UC patients (514 measurements) was analysed, and 100 age-matched healthy blood donors were used as controls.

Results

IL-6 serum levels were significantly elevated in active versus inactive CD and UC, also compared with healthy controls. However, only a fraction of IBD patients showed increased serum IL-6. IL-6 levels ranged up to 32.7 ng/mL in active CD (>?5000-fold higher than in controls), but also up to 6.9 ng/mL in inactive CD. Increases in active UC (up to 195 pg/mL) and inactive UC (up to 27 pg/mL) were less pronounced. Associations between IL-6 serum levels and C-reactive protein concentrations as well as leukocyte and thrombocyte counts were observed. Median sIL-6R and sgp130 levels were only increased by up to 15%, which was considered of no diagnostic significance.

Conclusions

Only a minority of IBD patients shows elevated IL-6 serum levels. However, in these patients, IL-6 is strongly associated with disease activity. Its soluble receptors sIL-6R and sgp130 do not appear useful as biomarkers in IBD.

     

Serum interleukin-6 receptor in polymyalgia rheumatica: a potential marker of relapse/recurrence risk

OBJECTIVE: To investigate the modulation of systemic levels of soluble interleukin-6 receptor (sIL-6R) and soluble gp130 (sgp130) in untreated and treated polymyalgia rheumatica (PMR) patients during a followup period of at least 24 months in order to evaluate the relationship of these molecules with clinical outcome and their feasibility to provide a prognostic tool in clinical practice. METHODS: We analyzed sIL-6R and sgp130 serum levels in 93 PMR patients, and 46 age-matched normal controls, at disease onset and at 1, 3, 6, 12, and 24 months of followup during corticosteroid therapy by enzyme-linked immunosorbent assay. RESULTS: No difference in sIL-6R and sgp130 levels was observed between PMR patients and normal controls at disease onset or during followup. A significant correlation was found between the number of relapses and sIL-6R concentrations at baseline and after 1, 3, and 12 months of therapy. No correlation was found between sgp130 levels and the number of relapses. Cox multivariate analysis indicated that the best model for predicting relapses was identified by sIL-6R levels and the hemoglobin value at baseline. We found that high sIL-6R levels combined with low hemoglobin values resulted in a 10.1-fold increased risk of relapse. CONCLUSION: Our data support the identification of a potential prognostic marker of PMR outcome that might have important implications in clinical practice. Because targeting sIL-6R with blocking antibodies has proven useful in other rheumatic disorders, our results could suggest the opportunity to evaluate sIL-6R-blocking treatment in patients with PMR and elevated levels of sIL-6R at disease onset.     

Soluble gp130 is up-regulated in the implantation window and shows altered secretion in patients with primary unexplained infertility

Members of the IL-6 family of cytokines, which includes leukemia inhibitory factor (LIF) and IL-11, play important roles in implantation. The activity of these cytokines is modified by soluble receptors such as the IL-6 receptor (sIL-6R). gp130 is a signal transduction molecule common to the receptor complexes of this family, and its soluble form (sgp130) antagonizes their actions. The purpose of this study was to determine whether secretion of IL-6, LIF, sIL-6R, and sgp130 was different in the endometrium of women with primary unexplained infertility compared with normal fertile women. Endometrial biopsies were taken between d LH+6 and +13 and cultured in serum-free medium for 4 h. Secretion of IL-6, LIF, sIL-6R, and sgp130 was measured in the supernatant by ELISA. We also measured the secretion of IL-6, sIL-6R, and sgp130 by endometrial biopsies taken throughout the menstrual cycle in normal fertile women. Secretion of sgp130 increased 20-fold between d 20 and 26 of the cycle, coinciding with the implantation window (proliferative phase, median, 27.0 pg/ml.mg; range, 23-36; d 20-26, median, 501.5 pg/ml x mg; range, 26.1-1344; P = 0.03). RT-PCR showed that none of the known splice variants of gp130 were present in endometrium, indicating that sgp130 is produced by proteolytic cleavage of the membrane-bound form. IL-6 secretion varied considerably between patients and was greatest during the secretory phase and at menstruation. No significant change was seen in sIL-6R during the cycle. Between LH+6 and +13, secretion of sgp130 was significantly reduced in the infertile group (median, 93.1 pg/ml.mg; range, 28.5-256; compared with the fertile group, median, 223 pg/ml x mg; range, 63-534; U-statistic = 37; P = 0.017). Secretion of IL-6, LIF, and sIL-6R did not differ between the two groups. Immunolocalization of gp130, IL-6R, and the LIF receptor showed that the glandular epithelium and also endothelial cells are targets for IL-6 and LIF. These findings show that during a normal menstrual cycle, sgp130 secretion is greatly increased between d LH+6 and +13, due to proteolytic cleavage of membrane-bound gp130. Infertile patients show reduced secretion of sgp130 compared with fertile controls during this period, which coincides with the implantation window.     

Soluble forms of the interleukin-6 signal-transducing receptor component gp130 in human serum possessing a potential to inhibit signals through membrane-anchored gp130

The interleukin-6 (IL-6) signal is transduced through membrane-anchored gp130, which is associated with IL-6 receptor (IL-6R) in the presence of IL-6. Soluble forms of gp130 (sgp130) with molecular weights of 90 and 110 Kd were found in human serum. In the presence of recombinant IL- 6 (rIL-6), serum sgp130 were capable of associating with serum sIL-6R. By the sandwich enzyme-linked immunosorbent assay, healthy human sera was shown to contain 390 +/- 72 ng/mL of sgp130. A mouse pro-B-cell line-derived transfectant, BAF-130, expressing human gp130 was used to examine the function of serum sgp130. When supplemented with rIL-6, human serum induced DNA synthesis in BAF-130 cells, whereas the serum deprived of sIL-6R did not. In contrast, the DNA synthesis induced in BAF-130 cells by rIL-6-supplemented serum was increased when the serum was deprived of sgp130. These results indicated that serum sgp130 could negatively regulate the IL-6 signal. Recently, gp130 has been shown to be involved in the signaling processes of oncostatin M, leukemia inhibitory factor, and ciliary neurotropic factor, in addition to those of IL-6. Recombinant sgp130 showed inhibitory effect on the biologic function of such cytokines. This work implies physiologic roles of naturally produced serum sgp130 in modulating signals through gp130.     

Circulating interleukin-6 significantly correlates to thyroid hormone in acute myocardial infarction but not in chronic heart failure

To investigate relationships between thyroid states and the cardiac endocrine system, we analyzed thyrotropin (TSH), thyroid hormone, plasma levels of interleukin-6 (IL-6) and brain natriuretic peptide (BNP) in 50 patients with chronic heart failure (CHF), in 30 patients with heart failure from acute myocardial infarction (AMI), and in 15 controls. Plasma levels of IL-6 and BNP in both CHF and AMI were significantly elevated, while free triiodothyronine (FT3) was significantly decreased compared to controls. FT3/free thyroxine (FT4) ratio was significantly decreased in CHF but not in AMI compared to controls. In CHF, diuretic treatment diminished circulating BNP but not IL-6, while diuretic treatment increased FT3/FT4 ratio. In AMI, FT3/FT4 ratio was significantly decreased 72 h compared to 12 h after the onset of AMI, while BNP and IL-6 were significantly increased 72 h compared to 12 h after the onset of AMI. In both CHF and AMI, BNP significantly correlated with FT4. On the other hand, significant correlations between IL-6 and FT3, and between IL-6 and FT3/FT4 ratio were detected in AMI but not in CHF. This preliminary study suggests that IL-6, BNP and thyroid hormone reflect ventricular dysfunction in both acute and chronic heart failure, and that IL-6 significantly relates to circulating thyroid hormone in AMI but not in CHF.     

High-dose glucocorticoids increase serum levels of soluble IL-6 receptor alpha and its ratio to soluble gp130: an additional mechanism for early increased bone resorption

OBJECTIVE: Glucocorticoids (GCs) at pharmacological doses stimulate bone resorption. Mechanisms of this action are unclear. The osteoclastogenic cytokine interleukin (IL)-6 acts through an oligomeric receptor consisting of two subunits, gp80 (or IL-6 receptor alpha, IL-6Ralpha) and gp130; both exist in membrane and soluble forms. Soluble IL-6Ralpha (sIL-6Ralpha) enhances, while sgp130 inhibits IL-6 signalling. In vitro, GCs enhance many effects of IL-6 by up-regulation of IL-6Ralpha. The aim of the present study was to assess acute changes of IL-6 system in the peripheral blood of patients given high-dose GCs. SUBJECTS AND METHODS: Serum levels of IL-6, sIL-6Ralpha, sgp130 and bone turnover markers were assessed before and each day during treatment in 24 multiple sclerosis (MS) patients undergoing high-dose (prednisolone, 15 mg/kg per day), short-term (3 to 5 days) intravenous GC therapy for relapse at the Regional Multiple Sclerosis Centre. RESULTS: An immediate and marked fall of osteocalcin and an early increase of C-terminal telopeptide of type I collagen were already noticed at day 2 (P < 0.001 and P < 0.02, respectively); both became more apparent in the subsequent days. IL-6 was always below or near the detection limit of our ELISA. sgp130 showed a slight increase. sIL-6Ralpha significantly increased, peaking at day 4 (P < 0.01). However, inter-individual variability of response was noticed. Four patients showed a slight decrease, while no change was observed in one patient and an increase was noticed in the remaining nineteen (maximum change ranging from +10% to +67% with respect to baseline). In these patients, a significant increase of sIL-6Ralpha/sgp130 ratio was apparent. No correlation was found between bone turnover markers and any measured component of the IL-6 system. CONCLUSIONS: sIL-6Ralpha and sIL-6Ralpha/sgp130 ratio are precociously increased in the peripheral blood of the vast majority of patients given high-dose, intravenous GCs. The increase of systemically available sIL-6Ralpha conceivably results in the enhancement of IL-6-dependent osteoclastogenesis. The role of such a mechanism in the bone loss observed in inflammatory and immune-mediated diseases (where abundancy of IL-6 in the bone microenvironment is expected) requires further investigation.     

The balance between soluble receptors regulating IL-6 trans-signaling is predictive for the RANKL/osteoprotegerin ratio in postmenopausal women with rheumatoid arthritis

The objective of this study is to investigate the relationship between soluble components of the interleukin 6 (IL-6) system mediating and modifying IL-6 trans-signaling and the RANKL–RANK–osteoprotegerin system in postmenopausal women with rheumatoid arthritis (RA). The following parameters were investigated in 126 postmenopausal women with RA: IL-6, soluble IL-6-receptor (sIL-6R), soluble glycoprotein 130 (sgp130), sRANKL, osteoprotegerin (OPG), osteocalcin, erythrocyte sedimentation rate and C-reactive protein in sera, pyridinolin and desoxypyridinolin crosslinks in the morning urine. Bone mineral density (BMD) was measured by dual X-ray absorptiometry at the lumbar spine (BMD-LS) and at the femoral neck (BMD-FN). Predictors of RANKL/OPG ratio and BMD were evaluated by multiple linear regression analysis. The following determinants of the RANKL/OPG ratio were identified: sIL-6R/sgp130 ratio and daily glucocorticoid (GC) dose as positive determinants in the whole group (R ² = 0.56; P = 0.001), sIL-6R/sgp130 ratio as the exclusive positive determinant in patients with GC therapy (R ² = 0.48; P = 0.001) and sgp130 as negative determinant in patients without GC (R ² = 0.42; P = 0.031). Sgp130 was highly significantly positively correlated with OPG in the whole group (P < 0.001) as well as in patients with (n = 70; P < 0.05) and without GC therapy (n = 56; P < 0.01). sIL-6R was the main negative predictor of BMD-LS (R ² = 0.41; P = 0.019). High sIL-6R/sgp130 ratio and/or low sgp130 are associated with a high sRANKL/OPG ratio in sera of postmenopausal women with RA indicating the critical significance of IL-6 trans-signaling for an increase in the RANKL/OPG ratio and of bone resorption. Inhibition of IL-6 trans-signaling may be an effective bone-protecting principle in postmenopausal women with RA.     

Receptor engagement by viral interleukin-6 encoded by Kaposi sarcoma-associated herpesvirus.

Receptor usage by viral interleukin-6 (vIL-6), a virokine encoded by Kaposi sarcoma- associated herpesvirus, is an issue of controversy. Recently, the crystal structure of vIL-6 identified vIL-6 sites II and III as directly binding to glycoprotein (gp)130, the common signal transducer for the IL-6 family of cytokines. Site I of vIL-6, however, comprising the outward helical face of vIL-6, where human IL-6 (hIL-6) would interact with the specific alpha-chain IL-6 receptor (IL-6R), is accessible and not occupied by gp130. This study examined whether this unused vIL-6 surface is available for IL-6R binding. By enzyme-linked immunosorbent assay, vIL-6 bound to soluble gp130 (sgp130) but not to soluble IL-6R (sIL-6R). Using plasmon surface resonance, vIL-6 bound to sgp130 with a dissociation constant of 2.5 microM, corresponding to 1000-fold lower affinity than that of hIL-6/sIL-6R complex for gp130. sIL-6R neither bound to vIL-6 nor affected vIL-6 binding to gp130. In bioassays, vIL-6 activity was neutralized by 4 monoclonal antibodies (mAbs) recognizing a domain within vIL-6 site I, mapped to the C-terminal part of the AB-loop and the beginning of helix B. The homologous region in hIL-6 participates in site I binding to IL-6R. In addition, binding of vIL-6 to sgp130 was interfered with specifically by the 4 neutralizing anti-vIL-6 mAbs. Based on the vIL-6 crystal structure, the vIL-6 neutralizing mAbs map outside the binding interface to gp130, suggesting that they either produce allosteric changes or block necessary conformational changes in vIL-6 preceding its binding to gp130. These results document that vIL-6 does not bind IL-6R and suggest that conformational change may be critical to vIL-6 function.     

Cytokines in patients with ischaemic heart disease or myocardial infarction

BACKGROUND: Cytokines are responsible for the modulation of immunological and inflammatory processes as well as proliferative responses and apoptosis. It has been recently suggested that such cytokines as interleukin 6 (IL-6), soluble interleukin 6 receptor (sIL-6R) and anti-inflammatory cytokines such as interleukin 10 (IL-10) may play a significant role in the pathogenesis of acute coronary syndromes. AIM: To assess serum concentration of IL-6, sIL-6R and IL-10 in patients with ischaemic heart disease or acute myocardial infarction (AMI). METHODS: The study group consisted of 74 patients (25 females, 49 males, aged 40-69 years) divided into three groups; group I - 18 patients with AMI (up to 12 hours from the onset of symptoms), group II - 31 patients with unstable angina and group III - 25 patients with stable angina. The control group consisted of 20 healthy subjects. RESULTS: The IL-6 and sIL-6R serum levels were significantly higher in patients from groups I and II compared with patients from group III and controls, whereas the IL-10 serum concentration was similar in all studied groups. In patients with acute coronary syndromes serum concentrations of examined cytokines were positively correlated with acute inflammatory phase parameters and classical risk factors such as body mass index, blood pressure and lipid levels. CONCLUSIONS: IL-6 and sIL-6R are markers of acute coronary syndromes and may be used for the identification of high-risk patients with unstable angina or AMI.     

Sensitization of unmyelinated sensory fibers of the joint nerve to mechanical stimuli by interleukin-6 in the rat: an inflammatory mechanism of joint pain

OBJECTIVE: Pain during mechanical stimulation of the joint and spontaneous pain are major symptoms of arthritis. An important neuronal process of mechanical hypersensitivity of the joint is the sensitization of thin myelinated Adelta fibers and unmyelinated C fibers innervating the joint. Because interleukin-6 (IL-6) is a major inflammatory mediator, we investigated whether this cytokine has the potential to sensitize joint afferents to mechanical stimuli. METHODS: In electrophysiologic experiments conducted on anesthetized rats, action potentials were recorded from afferent fibers supplying the knee joint. Responses to innocuous and noxious rotation of the tibia against the femur in the knee joint were monitored before and 1-2 hours after injection of test compounds into the joint cavity. RESULTS: Injection of IL-6 and coinjection of IL-6 plus soluble IL-6 receptor (sIL-6R) caused a gradual increase in the responses of C fibers to innocuous and noxious rotation within 1 hour. The increase in responses to IL-6 and IL-6 plus sIL-6R was prevented by coadministration of soluble glycoprotein 130 (sgp130), but sgp130 did not reverse established mechanical hyperexcitability. Responses of Adelta fibers were not altered by the compounds. While injection of sIL-6R alone into the normal knee joint did not influence responses to mechanical stimulation, injection of sIL-6R into the acutely inflamed knee joint caused an increase in responses. CONCLUSION: IL-6 has the potential to sensitize C fibers in the joint to mechanical stimulation. Thus, IL-6 contributes to mechanical hypersensitivity, most likely due to an action of IL-6 on nerve fibers themselves.