Mean platelet volume is an independent risk factor for myocardial infarction but not for coronary artery disease

After rupture of an arteriosclerotic plaque in a coronary artery, platelets play a crucial role in the subsequent thrombus formation, leading to myocardial infarction. An increased mean platelet volume (MPV), as an indicator of larger, more reactive platelets, may represent a risk factor for myocardial infarction. However, this hypothesis is still controversial and most studies addressing the role of MPV were performed comparing patients suffering from myocardial infarction with healthy controls. We intended to identify patients at high risk of suffering myocardial infarction in a group of patients with known coronary artery disease. One hundred and eighty-five consecutive patients with stable coronary artery disease were compared with 188 individuals who had suffered myocardial infarction. Patients within the highest quintile of MPV (> or = 11.6 fl) had a significantly higher risk of experiencing a myocardial infarction compared with patients within the lowest quintile (OR = 2.6, 95% CI 1.3-5.1) in a multivariate analysis that included sex, age, body mass index, hyperlipidaemia, hypertension, smoking and diabetes mellitus. Our results indicate that patients with pre-existing coronary artery disease and an increased MPV (> or = 11.6 fl) are at higher risk of myocardial infarction. These patients can be easily identified during routine haematological analysis and could possibly benefit from preventive treatment.  

Expression of proinflammatory cytokines and their inhibitors during the course of spontaneous bacterial peritonitis

The aim of this work was the evaluation, in cirrhotic patients with noninfected ascites and with spontaneous bacterial peritonitis (SBP), of serum and ascitic fluid levels of proinflammatory cytokines [interleukin (IL) 1-, tumor necrosis factor (TNF-), and IL6] and antiinflammatory compounds [IL10, soluble IL-1 receptor antagonist (sIL-1Ra), soluble receptors of TNF p55 and p75 (sTNFR55 and sTNFR75), and soluble receptor of IL6 (sIL6R)], as well as their relationship with the outcome of the infection in those with SBP. These molecules were assayed by ELISA in noninfected cirrhotic controls (n = 15), patients with SBP (n = 32), and healthy controls (n = 20). Serum levels of IL6 and of the majority of antiinflammatory mediators, sIL1Ra, sTNFR75, and sIL6R, were higher in control cirrhotic patients compared to healthy subjects. SBP was associated with significantly elevated ascitic fluid levels of every one of the proinflammatory cytokines compared to those in cirrhotic controls. Also, serum levels of IL10 and both TNF receptors and ascitic fluid levels of sIL1Ra and sTNFR55 were higher in patients with SBP compared to cirrhotic controls. Ascitic fluid levels of proinflammatory cytokines decreased rapidly after resolution of the infection; however, nonsignificant changes were detected in ascitic fluid concentrations of antiinflammatory molecules. Thus, elevated levels of antiinflammatory compounds both in noninfected cirrhotic patients and in patients with SBP suggest a regulatory control of the inflammatory process by these molecules in liver cirrhosis patients.  

Activity of interleukin 6 in the differentiation of monocytes to macrophages and dendritic cells

Peripheral blood monocytes are common precursor cells of dendritic cells (DCs) and macrophages. We have searched for factors with the potential to regulate the differentiation of monocytes to DCs and macrophages. When CD14+ monocytes are cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL) 4, the CD14+CD1a- population, which consists of macrophages, was found in the serum-containing cultures but not in the serum-free cultures. Addition of IL-6 receptor-neutralizing monoclonal antibody (mAb) or gp130-neutralizing mAb to the serum-containing cultures resulted in a decreased population of CD14+CD1a- cells. An increase in the CD14+CD1a- population with reduction in CD14-CD1a+ DCs was observed with the addition of IL-6 to cultures, whereas IL-11, leukaemia inhibitory factor, oncostatin M or macrophage colony-stimulating factor did not affect the differentiation of monocytes in the presence of GM-CSF plus IL-4. This effect of IL-6 was blocked by tumour necrosis factor alpha (TNF-alpha), lipopolysaccharide (LPS), IL-1beta, CD40 ligand (CD40L) and transforming growth factor beta1 (TGF-beta1). Among these factors, TNF-alpha was most potent in interfering with the action of IL-6. These results suggest that IL-6 inhibits the differentiation of monocytes to DCs by promoting their differentiation toward macrophages, which is modulated by factors such as TNF-alpha, LPS, IL-1beta, CD40L and TGF-beta1.  

Coagulation and activation of inflammatory pathways in the development of functional decline and mortality in the elderly

PURPOSE: This study was performed to determine the effects of markers of inflammation (interleukin 6) and coagulation (D-dimer) on mortality and functional status in older persons. METHODS: Subjects were selected for the Duke Established Populations for Epidemiologic Studies of the Elderly. In 1992, 2569 subjects (age >71 years) were interviewed, of whom 1,723 had interleukin-6 and D-dimer measurements. Values of interleukin 6 and D-dimer were categorized into quartiles. Outcomes were mortality (through 5 years) and functional status (through 4 years). Relative risks were estimated with proportional hazards models that adjusted for potential confounders. RESULTS: The relative risk of mortality was 1.28 (95% confidence interval [CI]: 0.98 to 1.69; P = 0.06) for those with only interleukin-6 levels in the highest quartile, 1.53 (95% CI: 1.18 to 1.97; P = 0.001) for subjects with only D-dimer levels in the highest quartile, and 2.00 (95% CI: 1.53 to 2.62; P = 0.0001) for those with levels of both in the highest quartile, as compared with those who were not in either of the highest quartiles. Those with high interleukin-6 and high D-dimer levels had the greatest declines in all measures of function. CONCLUSION: Activation of the coagulation and inflammatory pathways is associated with mortality and decline in function, and may be part of the explanation for the development of a frailty phenotype in the elderly.  

Lack of gp130 expression in hepatocytes promotes liver injury

BACKGROUND & AIMS: Interleukin 6 (IL-6) contributes via its signal transducer gp130 to the acute phase response (APR) in hepatocytes. Recent studies indicated that IL-6 is involved in the regulation of different pathophysiologic conditions of the liver. To define the IL-6-dependent intracellular pathways more specifically, we generated a hepatocyte-specific gp130 knockout mouse. METHODS: Hepatocyte-specific gp130-deficient mice were generated using the Cre-loxP system. Expression of the Cre recombinase was under the control of a hepatocyte-specific control element. Adult mice were challenged with IL-6, oncostatin M (OSM), and LPS. RESULTS: Cre expression started at day 10.5 postconception, and a complete deletion of gp130 in hepatocytes was found at day 14 during liver development. The adult liver of these mice showed no abnormalities; however, after IL-6 and OSM stimulation, gp130-dependent pathways (STAT3, APR gene expression) were completely blocked in the liver of these animals. Additionally, challenging hepatocyte-specific gp130 knockout animals with lipopolysaccharides (LPS) lead to an onset of acute liver injury with an increase of hepatocyte apoptosis associated with elevated tumor necrosis factor alpha (TNF-alpha) serum levels and reduced nuclear factor kappaB (NF-kappaB) activation in hepatocytes. CONCLUSIONS: Our findings demonstrate that gp130 is of minor relevance for embryonal development of hepatocytes. However, the molecule has an essential role in controlling acute phase gene expression and provides hepatocellular protection after LPS challenge.  

Hepatic apoptosis and proliferation in male and female rats fed alcohol: role of cytokines

Background: The female liver is more sensitive to the toxic effect of chronic alcohol intake than the male liver. The aim of the study was to compare the influence of gender and sex hormonal status on apoptosis and cell proliferation following chronic ethanol intake.
Methods: Male and female rats were pair fed for 8 weeks a liquid diet containing 36% of their total daily calories as ethanol (ETOH group) or sucrose (control group). Liver samples were analyzed for apoptosis and hepatocyte proliferation by immunohistochemistry. The hepatic production of factors able to influence cell death and proliferation, such as tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6) were determined.
Results: In both male and female rats, ethanol intake promoted apoptosis in the liver. This effect of ethanol was more evident in female than male rat livers. Hepatic TNFα levels, which promote apoptosis, are significantly more elevated in female than in male livers. Hepatic IL-6 production, which promotes hepatocyte proliferation, was induced by ethanol only in males, but not female animals.
Conclusion: This observed difference in cytokine responses may contribute to the enhanced sensitivity of female liver to EtOH-induced injury.  

Elevated circulating levels of heat shock protein 70 are related to systemic inflammatory reaction through monocyte Toll signal in patients with heart failure after acute myocardial infarction

BACKGROUND: Recent studies have shown that heat shock protein (HSP) 70 may serve as a "damage signal" to the immune system and could be the endogenous ligand for Toll-like receptor (TLR) 4 mediating synthesis of inflammatory cytokines. AIMS: To explore the relationship between circulating HSP70 levels and activation of monocyte TLR4 and myocardial damage after AMI. METHODS AND RESULTS: This study examined circulating HSP70 and monocyte TLR4 levels in 52 patients with AMI and 20 controls, and analyzed ex vivo inflammatory cytokine productions using HSP70-stimulated monocytes. Circulating HSP70 levels were higher in AMI patients on day 1 after onset than in controls and remained elevated in AMI patients 14 days after onset. HSP70 levels were positively correlated with monocyte TLR4, plasma interleukin-6 and tumor necrosis factor-alpha levels in AMI patients. HSP70 levels 14 days after onset were higher in AMI patients with heart failure (n=15) than in those without heart failure. In our in vitro study, HSP70-stimulated monocytes resulted in dose-dependent TLR4 expression and release of inflammatory cytokines. TLR4 antibody inhibited inflammatory cytokines release. CONCLUSIONS: Elevated circulating levels of HSP70 may be involved in TLR4 signal-mediated immune response and the progression of heart failure after AMI.