Plasma adrenomedullin concentration is increased in patients with peripheral arterial occlusive disease associated with vascular inflammation

Adrenomedullin (AM), a potent vasodepressor, is known to have anti-atherosclerotic and anti-inflammatory effects. However, there is no information about its level in severe atherosclerotic diseases, such as peripheral arterial occlusive disease (PAOD). The present study investigated the plasma concentration of AM and several inflammatory parameters in 72 patients with and without PAOD. The plasma AM concentration in patients with PAOD was significantly higher than in those without PAOD. Its concentration had significant correlations with ankle-brachial index and Fontaine's stage. The plasma AM level also correlated with high sensitive C-reactive protein and interleukin-6. As an additional study, plasma levels of two forms of AM drawn from the femoral artery and saphenous vein were measured in 27 other subjects. Both mature and intermediate forms of plasma AM in the femoral artery and saphenous vein were higher in patients with PAOD than in those without PAOD. A significant step-up of the mature form of AM from the femoral artery to the saphenous vein was observed. Our findings indicate that the plasma AM concentration was elevated in patients with PAOD in proportion to the severity of the disease and associated with vascular inflammation. An increased production of AM in PAOD may play a protective role against advanced atherosclerosis with an inflammatory signature.     

IL-6 Transsignaling in Patients with Chronic Spontaneous Urticaria

Background

IL-6 trans-signaling is critically involved in the initiation and promotion of inflammatory and autoimmune diseases. Therefore, we investigated the clinical relevance of soluble members of IL-6 trans-signaling system in chronic spontaneous urticaria (CSU).

Methods

IL-6, interleukin 6 soluble receptor (IL-6 sR) and soluble gp130 (sgp130) were measured by ELISA method in plasma from CSU patients and the healthy subjects. The data were related to activation of the acute phase response as indicated by serum C-reactive protein (CRP) concentration and compared between patients stratified by the disease activity.

Results

Concentrations of IL-6, IL-6 sR, sgp130 in plasma and CRP in serum were significantly elevated in CSU patients compared with the healthy controls. CRP correlated significantly with IL-6 and sgp130, similarly IL-6 correlated significantly with sgp130. By contrast, CRP and IL-6 did not correlate significantly with IL-6 sR. However, significant correlation was noted between IL-6 sR and sgp130.

Conclusions

Concentrations of IL-6 and its soluble receptors were significantly elevated in patients with CSU, suggesting upregulation of the IL-6 trans-signaling in the disease. In addition, our results support the concept that the system may be involved in pathogenesis of the systemic inflammatory activation in CSU patients.     

Interleukin 1B gene polymorphism is associated with baseline C-reactive protein levels in healthy individuals

C-reactive protein (CRP) is a sensitive marker of inflammation induced by both IL-6 and IL-1. Thus, genetic variation in these genes could be associated with the variety in C-reactive protein levels, and therefore with the severity of the entire inflammatory response. Even a subtle elevation in baseline CRP levels in healthy individuals has been found to significantly increase the risk for cardiovascular diseases. Therefore, to find out the possible role of pro-inflammatory cytokines in CRP baseline regulation we conducted a study of 338 healthy blood donors whose CRP levels were determined and whose single nucleotide polymorphisms of IL1A(C/T)-889, IL1B(C/T)-511, IL1B(C/T) + 3954, IL6(G/C)-174 and ILRN (a VNTR) both genotyped and haplotyped. The data revealed an association between CRP levels and the IL1B + 3954 genotype. Also, the bilocus haplotype IL1B-511*1/IL1B + 3954*2 was more frequent in subjects with below median CRP levels (< 0.72 mg/l), and composite genotype analysis of IL1B-511/IL1B + 3954 supported this finding. Our findings suggest that in healthy people, basal CRP levels are regulated by IL1B but not by IL6 genetics.     

Plasma procalcitonin in patients with ileus. Relations to other inflammatory parameters

Plasma procalcitonin (PCT) is a highly specific marker for the diagnosis of bacterial infections and sepsis. PCT levels are usually low in viral infections, chronic inflammation or postsurgical states. The purpose of this study was to characterize PCT plasma levels in patients with various types of ileus at preoperative stage, where the other inducing factors suchas a surgical stress are excluded. The prospective study was performed on 54 patients admitted to in-patient surgical department with a proven diagnosis of ileus. Patients were divided to three groups--obstructive, vascular and paralytic ileus. Plasma levels of PCT (Kryptor analysis), TNFalpha, IL-1beta, IL-6, cortisol (ELISA) and CRP (Kryptor ultrasensitive analysis) were estimated before any invasive procedure was realized. We demonstrated significant elevation of PCT in both obstructive ileus in adhesions and vascular ileus compared with healthy subjects (p 0.01). PCT levels were not elevated in paralytic ileus. The regression coefficient was the highest for PCT and CRP (r=0.78, p 0.01), for TNFalpha and IL-8 (r=0.76, p 0.01) in vascular ileus. There was no significant correlation between PCT and other inflammatory parameters. The different types of ileus induce an elevation of plasma PCT levels and PCT shows itself as an acute phase reactant. The highest PCT concentrations were presented in patients with vascular ileus, whereas paralytic ileus revealed similar cytokine and PCT pattern as in healthy subjects. Plasma PCT estimation extended to a measurement of CRP and IL-6 may become a useful complementary examination for diagnostics of acute abdomen in patients.     

Hormonal modulation of interleukin-6, tumor necrosis factor and associated receptor secretion in postmenopausal women

Hormone replacement therapy (HRT) reduces the risk for osteoporosis but transiently increases cardiovascular risk for some postmenopausal women. This study investigated the hypothesis that these risks are associated with HRT-induced changes in mononuclear cell secretion of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and associated soluble receptors. Compared to the untreated condition (n=8), estrogen therapy (n=7) and estrogen+progestin therapy (n=7) both caused 2-fold elevations in TNF-alpha secretion. IL-6 secretion was increased (48%, P=0.04) only by estrogen+progestin therapy. Although soluble receptor secretion was not different among groups, soluble TNF receptor type I and IL-6 receptor secretion were inversely related to plasma follicle stimulating hormone (P<0.05). Both therapies reduced plasma osteocalcin (a marker for osteoporosis) by approximately 50% (P<0.002). Plasma C-reactive protein (CRP, a marker for cardiovascular risk) was 3-fold higher in women receiving only estrogen, compared to untreated women (P=0.01), and twice as high as those receiving estrogen+ progestin (P=0.045). Simple linear relationships were not observed between cytokine secretion and these markers, but a significant HRT/TNF-alpha interaction with osteocalcin (P=0.022) and an HRT/IL-6 interaction with CRP (P =0.016) indicated more complex relationships between hormone replacement, cytokine activity, and health risks associated with menopause.     

Increased leptin expression selectively in the hypothalamus suppresses inflammatory markers CRP and IL-6 in leptin-deficient diabetic obese mice

Low-grade systemic inflammation, as indicated by increased circulating levels of inflammatory markers CRP and IL-6, is linked to increased risks for cardiovascular diseases (CVD) and diabetes mellitus in obese subjects. Whereas hyperleptinemia in obesity are associated with increased CRP and IL-6 release, the hypothalamic versus peripheral site of leptin action has not been ascertained. The effects of increased leptin supply selectively in the hypothalamus by gene therapy on pro-inflammatory CRP and IL-6 levels and on markers of diabetes in the circulation of ob/ob mice displaying either age-related or dietary obesity were assessed. A recombinant adeno-associated viral vector encoding either green-fluorescent protein (control) or leptin gene was injected intracerebroventricularly. Five weeks later, one-half of each of the vector groups was switched to high-fat diet consumption and the other half continued to consume regular low-fat chow diet. Body weight and visceral white adipose tissue were drastically reduced and hyperinsulinemia and hyperglycemia were abrogated by leptin gene therapy, independent of the dietary fat content. The elevated plasma CRP and IL-6 levels seen in obese ob/ob mice receiving the control vector, regardless of the fat content of the diet, were markedly suppressed by increased hypothalamic leptin in both groups. The results show for the first time that leptin deficiency elevates and reinstatement of leptin selectively in the hypothalamus suppresses the release of pro-inflammatory biomarkers, a response likely to alleviate CVD associated with obesity.     

Grape-seed procyanidins prevent low-grade inflammation by modulating cytokine expression in rats fed a high-fat diet

ObjectiveThe main objective of this study was to evaluate the effect of procyanidin intake on the level of inflammatory mediators in rats fed a hyperlipidic diet, which are a model of low-grade inflammation as they show an altered cytokine production.DesignMale Zucker Fa/fa rats were randomly grouped to receive a low-fat (LF) diet, a high-fat (HF) diet or a high-fat diet supplemented with procyanidins from grape seed (HFPE) (345 mg/kg feed) for 19 weeks and were then euthanized. We determined biochemical parameters, C-reactive protein (CRP) and IL-6 levels in plasma. Adipose tissue depots and body weight were also determined. We assessed CRP, IL-6, TNF-α and adiponectin gene expression in liver and white adipose tissue (WAT).ResultsAs expected, rats fed the HF diet show an enhanced production of CRP. Our results demonstrate that the HFPE diet decreases rat plasma CRP levels but not IL-6 levels. The decrease in plasma CRP in HFPE rats is related to a down-regulation of CRP mRNA expression in the liver and mesenteric WAT. We have also shown a decrease in the expression of the proinflammatory cytokines TNF-α and IL-6 in the mesenteric WAT. In contrast, adiponectin mRNA is increased in this tissue due to the procyanidin treatment.As previously reported, CRP plasma levels correlate positively with its expression in the mesenteric WAT, suggesting that procyanidin extract (PE) modulates CRP at the synthesis level. CRP plasma levels also correlate positively with body weight. As expected, body weight is associated with the adiposity index. Also, TNF-α expression and IL-6 expression have a strong positive correlation. In contrast, the expression of the anti-inflammatory cytokine adiponectin correlates negatively with the expression of TNF-α and IL-6 in the mesenteric WAT.ConclusionThese results suggest a beneficial effect of PE on low-grade inflammatory diseases, which may be associated with the inhibition of the proinflammatory molecules CRP, IL-6 and TNF-α and the enhanced production of the anti-inflammatory cytokine adiponectin. These findings provide a strong impetus to explore the effects of dietary polyphenols in reducing obesity-related adipokine dysregulation to manage cardiovascular and metabolic risk factors.     

COPD患者C反应蛋白、TNF-α、IL-8、IL-6临床研究

目的：探讨血清中C反应蛋白（CRP）、肿瘤坏死因子-α（TNF-α）、白介素-8（IL-8）、白介素-6（IL-6）的水平变化在慢性阻塞性肺疾病（COPD）的发生发展中的作用及临床意义。方法：采用酶联免疫吸附法及全自动生化仪对35例COPD患者急性发病期和缓解期血清中的CRP、TNF-α、IL-8和IL-6浓度进行检测。结果：①COPD缓解期CRP、TNF-α、IL-8和IL-6含量显著低于急性期,但仍高于对照组（P〈0.05）。②吸烟因素可增加COPD患者血清中CRP、TNF-α、IL-8和IL-6含量。③血清中CRP、TNF-α、IL-8和IL-6含量与肺功能指标FEV1%和FEV1/FVC%呈负相关。结论：CRP、TNF-α、IL-8和IL-6参与了COPD患者气道炎症反应,可能与疾病的严重程度有关,可作为判断预后的辅助指标;吸烟可能是COPD发生发展的重要因素。     

肥胖患者载脂蛋白M水平及其与炎症因子的关系研究

目的：观察肥胖患者载脂蛋白M水平并探讨其与炎症因子的关系。方法：58例体重正常者和36例肥胖患者常规测量体重、身高,计算体重指数,抽取空腹静脉血检测血脂、血浆载脂蛋白M（apoM）、白细胞介素-6（IL-6）、C反应蛋白（CRP）、肿瘤坏死因子α（TNF—α）。结果：肥胖患者血浆apoM、高密度脂蛋白胆固醇（HDL-C）降低（P〈0．05）,IL-6、TNF—α、CRP水平升高（P〈0．05）,肥胖患者血浆αpoM与HDL-C正相关,血浆αpoM与IL-6、TNF—α、CRP水平负相关。结论：肥胖患者血浆apoM显著降低,αpoM水平与CRP、TNF-α、IL-6水平密切相关,apoM可能受到这些炎症因子的调控。     

Inflammatory cytokines and malnutrition as related to risk for cardiovascular disease in hemodialysis patients

Malnutrition and inflammation are associated with end-stage renal disease (ESRD). Interleukin (IL)-6 and tumor necrosis factor alpha (TNF-alpha) powerfully predict death from cardiovascular disease. The aim of our study was to establish an association between markers of inflammation and parameters of malnutrition in patients on hemodialysis. The study population consisted of 42 hemodialysis patients with different parameters of malnutrition. Blood samples were taken after an overnight fast, and plasma lipid profiles (total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides) were measured by using conventional enzymatic methods. Serum urea and creatinine levels were also measured by routine procedures. Plasma high-sensitivity C-reactive protein level (hs-CRP), TNF-alpha, and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). Standard Doppler echo examinations were used to determine plaque on carotid arteries, and end-diastolic diameter (EDD) and ejection fraction (EF) were measured by echocardiography. Malnourished patients exhibited significantly greater evidence of cardiovascular disease and carotid plaques. Factor (principal component) analysis indicated 6 latent factors with 67.5% of the variance explained within all investigated parameters. Cluster analysis was used to distinguish the inflammatory markers and the nutritional markers from other parameters and to visualize similarities between variables. In summary, this cross-sectional study in hemodialysis patients found a high prevalence of malnutrition, inflammation, carotid plaques, and cardiovascular disease. Malnourished dialysis patients are more often found with cardiovascular disease and carotid plaques. In addition, these patients have higher levels of inflammatory cytokines, which may partly explain the elevated risk for atherosclerotic vascular disease.     

Quest for novel cardiovascular biomarkers by proteomic analysis

Atherosclerosis, and the resulting coronary heart disease and stroke, is the most common cause of death in developed countries. Atherosclerosis is an inflammatory process that results in the development of complex lesions or plaques that protrude into the arterial lumen. Plaque rupture and thrombosis result in the acute clinical complications of myocardial infarction (MI) and stroke. Although certain risk factors (dyslipidemias, diabetes, hypertension) and humoral markers of plaque vulnerability (C-reactive protein, interleukin-6, 10 and 18, CD40L) have been identified, a highly sensitive and specific biomarker or protein profile, which could provide information on the stability/vulnerability of atherosclerotic lesions, remains to be identified. In this review, we report several proteomic approaches which have been applied to circulating or resident cells, atherosclerotic plaques or plasma, in the search for new proteins that could be used as cardiovascular biomarkers. First, an example using a differential proteomic approach (2-DE and MS) comparing the secretome from control mammary arteries and atherosclerotic plaques is displayed. Among the different proteins identified, we showed that low levels of HSP-27 could be a potential marker of atherosclerosis. Second, we have revised several studies performed in cells involved in the pathogenesis of atherosclerosis (foam cells and smooth muscle cells). Another approach consists of performing proteomic analysis on circulating cells or plasma, which will provide a global view of the whole body response to atherosclerotic aggression. Circulating cells can bear information reflecting directly an inflammatory or pro-coagulant state related to the pathology. As an illustration, we report that circulating monocytes and plasma in patients with acute coronary syndromes has disclosed that mature Cathepsin D is increased both in the plasma and monocytes of these patients. Finally, the problems of applying proteomic approach directly to plasma will be discussed. The purpose of this review is to provide the reader with an overview of different proteomic approaches that can be used to identify new biomarkers in vascular diseases.     

C-reactive protein (CRP) gene polymorphisms: implication in CRP plasma levels and susceptibility to acute myocardial infarction

C-reactive protein (CRP) is one of the many molecular factors involved in pathogenesis of coronary artery disease which its plasma levels are associated with increased risk of cardiovascular events. The present study designed to determine whether polymorphisms in the CRP gene are associated with plasma CRP levels and susceptibility to acute myocardial infarction (AMI). Plasma CRP levels were measured in patients with AMI and control subjects and genomic DNA and peripheral blood mononuclear cells (PBMCs) were extracted. The −717A/G and 1059G/C CRP polymorphisms were detected. The mRNA expression of CRP gene and plasma levels of CRP and interleukin-6 (IL-6) were also analyzed. The −717A/G variation was significantly associated with higher CRP levels, but 1059G/C variation was associated with lower CRP levels. The AA genotype frequency of −717A/G variation was significantly more frequent in the patients than control subjects. By contrast, the genotype and allele distribution in 1059G/C of patient were not statistically different between patients and controls. There were significant differences in circulating levels of CRP and IL-6 in the patients than in controls. The mRNA expression levels of CRP were significantly higher in the patient plasma compared with controls. Our results indicate relationship between many polymorphisms in CRP gene and risk of AMI which suggest that genetic variations in CRP might be helpful for determining susceptibility to AMI in Iranian patients. In addition, CRP gene polymorphisms are associated with plasma CRP levels and susceptibility to AMI might be related to CRP gene expression which affects its plasma levels.     

Phospholipid transfer protein activity is associated with inflammatory markers in patients with cardiovascular disease

Plasma phospholipid lipid transfer protein (PLTP) has several known key functions in lipoprotein metabolism. Recent studies suggest that it also may play a role in the inflammatory response. Inflammatory cell activity contributes to the development of atherosclerosis. To seek further evidence for the association of PLTP with inflammation, we studied the relationship between PLTP activity and five inflammatory markers [C-reactive protein (CRP), serum amyloid A (SAA), interleukin 6 (IL-6), white blood cells (WBC), and fibrinogen] in 93 patients with low HDL and cardiovascular disease (CVD). Plasma PLTP activity had the strongest correlation with CRP (r=0.332, P<0.001) followed by SAA (r=0.239, P=0.021). PLTP, CRP, and SAA were significantly associated with body mass index (BMI), insulin or glucose, apolipoprotein (apo) B, and/or apo E level (r=0.264-0.393, P<0.01). PLTP, SAA, and IL-6 also were associated with the concentration of HDL particles without apo A-II [Lp(A-I)](r=0.373-0.472, P<0.005, n=56), but not particles with apo A-II. Smoking was associated with increased PLTP activity, CRP, and WBC, and hypertension with increased PLTP activity. In linear models, CRP remained significantly associated with PLTP after adjustment of CVD risk factors and insulin resistance. Also, much of the variability of plasma PLTP activity was explained by CRP, BMI, Lp(A-I), smoking, glucose, and blood pressure. These findings show for the first time that plasma PLTP activity is associated positively with CRP in CVD, a state of chronic inflammation.     

慢性肾小球肾炎患者治疗前后血清CRP和VEGF浓度变化及临床意义

目的：研究慢性肾小球肾炎（CNG）中血清C反应蛋白（CRP）和血管内皮生长因子（VEGF）的浓度变化及其临床意义。方法：采用ELISA法测定35例正常对照组与41例慢性肾小球肾炎患者治疗前后血清IL-6和VEGF的浓度,同时放射免疫分析法测定血清TNF-α浓度,免疫比浊法测定血清CRP与尿Alb浓度。结果：①治疗前后CNG患者血清中IL-6、TNF-α和CRP较正常对照组均显著升高（P〈0.05或P〈0.01）,但治疗后IL-6、TNF-α和CRP水平显著低于治疗前（P〈0.01）,且血清CRP与IL-6和TNF-α呈正相关（P〈0.01）。②治疗后,CNG患者血清VEGF水平与尿Alb含量较治疗前明显降低（P〈0.05或P〈0.01）,仍显著高于正常对照组（P〈0.05或P〈0.01）,且血清VEGF与尿Alb水平呈正相关（P〈0.01）。结论：CRP、IL-6和TNF-α参与了CNG患者慢性炎症反应,VEGF则与蛋白尿的产生密切相关,治疗前后血清CRP和VEGF检测对于慢性肾小球肾炎的病情了解及临床疗效评估均具有重要的临床价值。     

Correlation between two markers of inflammation, serum C-reactive protein and interleukin 6, and indices of oxidative stress in patients with high risk of cardiovascular disease.

As evidence of the involvement of inflammation and oxidative damage in pathogenesis of age-related chronic diseases is growing, epidemiologists need to develop measures of both conditions to study their relationships in human populations. One way of searching for appropriate biomarkers is to examine correlations between different inflammatory markers and oxidative indices. We examined cross-sectional correlations between two inflammatory markers, serum C-reactive protein (CRP) and interleukin (IL)-6, and three oxidative indices, plasma levels of alpha-tocopherol and beta-carotene, and urinary levels of 2,3-dinor-5,6-dihydro-15-F2t-isoprostane (F2-IsoP), in 60 individuals at high risk of cardiovascular disease. Correlations between the biomarkers were examined graphically and using the Pearson correlation coefficient. No correlation was found between plasma levels of alpha-tocopherol and either of the inflammatory markers. Plasma beta-carotene inversely correlated with IL-6 (r = -0.46, p=0.0002) and CRP (r = -0.41, p = 0.001). Although urinary F2-IsoP did not correlate with IL-6, this biomarker positively correlated with CRP (r = 0.31, p = 0.002). As only urinary F2-IsoP levels have been validated against known oxidative assaults, their positive association with CRP levels is interpreted as evidence of an interconnection between low-level inflammation and oxidative status. Urinary levels of F2-IsoP and serum levels of CRP represent appropriate biomarkers for future studies of inflammation and oxidative status in humans.     

Interleukin-6 as an independent predictor of future cardiovascular events in high-risk Japanese patients: comparison with C-reactive protein

Inflammation is associated with the development of atherosclerotic vascular lesions and some inflammatory parameters are used as cardiovascular (CV) risk markers. The present study was designed to assess the predictive power of interleukin (IL)-6 for future CV events. In 121 Japanese patients with multiple CV risk factors and/or disease, serum concentrations of IL-6 and high sensitive C-reactive protein (hs-CRP) were measured. During follow-up periods (mean, 2.9 years) after the baseline assessment, 50 patients newly experienced CV events such as stroke/transient ischemic attack (n=10), heart failure hospitalization (n=6), acute coronary syndrome (n=7), and revascularization for coronary artery disease (n=15) and peripheral arterial disease (n=12). The serum level of IL-6, but not hs-CRP, was significantly higher in patients who had CV events than in event-free subjects (3.9±2.6 and 3.0±2.2 pg/mL, P=0.04). When the patients were divided into three groups by tertiles of basal levels of IL-6 (<1.85, 1.85-3.77, and ≥3.77 pg/mL), cumulative event-free rates by the Kaplan-Meier method were decreased according to the increase in basal IL-6 levels (65%, 50%, and 19% in the lowest, middle, and highest tertiles of IL-6, respectively; log-rank test, P=0.002). By univariate Cox regression analysis, previous CV disease, creatinine clearance, and serum IL-6 levels were significantly associated with CV events during follow-up. Among these possible predictors, the highest tertile of IL-6 was only an independent determinant for the morbidity in the multivariate analysis (hazard ratio 2.80 vs. lowest tertile, P=0.006). These findings indicate that IL-6 is a powerful independent predictor of future CV events in high-risk Japanese patients, suggesting its predictive value is superior to that of hs-CRP.     

Interleukin-6, but not soluble adhesion molecules, predicts a subsequent mortality from cardiovascular disease in patients with acute ST-segment elevation myocardial infarction

Inflammatory responses are an important element in the atherosclerotic process. Therefore, inflammatory markers can potentially serve as predictors of cardiovascular risk. However, the existing data are limited and controversial. We conducted a prospective cohort study with 263 patients with first acute ST-segment elevation myocardial infarction (STEMI) who were admitted to our Hospital within 6 h after the symptoms onset. Clinical data were recorded and serum admission levels of interleukin-6 (IL-6), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble P-selectin (sP-selectin) were determined. The patients were then followed up for 3 years to document cardiovascular mortality. During the follow-up, 34 patients died from cardiovascular causes. The admission levels of IL-6 were significantly higher in these patients, whereas sICAM-1, sVCAM-1, and sP-selectin were comparable between these and the survived patients. The Kaplan–Meier plots revealed a significant increase in cardiovascular mortality with increasing levels of IL-6 (P = 0.0002, χ² test). The logistic regression analysis indicated that IL-6 was an independent predictor for cardiovascular mortality. To conclude, our findings indicate that elevated admission levels of IL-6, but not soluble adhesion molecules, provide valuable information for risk assessment of long-term cardiovascular mortality in patients with STEMI.