Jan Kristian Damås

Increased Expression of Visfatin in Macrophages of Human Unstable Carotid and Coronary Atherosclerosis Possible Role in Inflammation and Plaque Destabilization

Background— Although the participation of inflammation in atherogenesis is widely recognized, the identification of the different components has not been clarified. In particular, the role of inflammation in plaque destabilization is not fully understood. Methods and Results— Our main findings were as follows: (1) In a microarray experiment, we identified visfatin, one of the most recently identified adipokines, as a gene that was markedly enhanced in carotid plaques from symptomatic compared with plaques from asymptomatic individuals. This finding was confirmed when carotid plaques from 7 patients with asymptomatic and 14 patients with symptomatic lesions were examined with real-time reverse transcription polymerase chain reaction. (2) Immunohistochemistry showed that visfatin was localized in areas that were rich in lipid-loaded macrophages. (3) The relationship between visfatin and unstable lesions was also found in patients with coronary artery disease, demonstrating a strong visfatin immunostaining in lipid-rich regions within the material obtained at the site of plaque rupture in patients with acute myocardial infarction. (4) Both oxidized low-density lipoprotein and tumor necrosis factor-&agr; increased visfatin expression in THP-1 monocytes, with a particularly enhancing effect when these stimuli were combined. (5) Visfatin increased matrix metalloproteinase-9 activity in THP-1 monocytes and tumor necrosis factor-&agr; and interleukin-8 levels in peripheral blood mononuclear cells. Both of these effects were abolished when insulin receptor signaling was blocked. Conclusions— Our findings suggest that visfatin should be regarded as an inflammatory mediator, localized to foam cell macrophages within unstable atherosclerotic lesions, that potentially plays a role in plaque destabilization.

Systemic inflammation in heart failure--the whys and wherefores.

Patients with chronic heart failure (HF) are characterized by systemic inflammation, as evident by raised circulating levels of several inflammatory cytokines with increasing levels according to the degree of disease severity. In addition to the myocardium itself, several tissues and cells can contribute to this inflammation, including leukocytes, platelets, tissue macrophages and endothelial cells. Although the mechanisms for the systemic inflammation is unknown, both infectious (e.g., endotoxins) and non-infectious (e.g., oxidative stress and hemodynamic overload) events could be operating, also including activation of Toll-like receptors as well as interaction with the neurohormone system. A growing body of evidence suggests that this systemic inflammation in chronic HF may play a role in the development and progression of this disorder, not only by promoting myocardial dysfunction, but also by inducing pathogenic consequences in other organs and tissues, thereby contributing to additional aspects of the HF syndrome such as cachexia, endothelial dysfunction and anemia. Although this inappropriate immune activation and inflammation could represent a new target for therapy in patients with chronic HF, the anti-tumor necrosis factor trials have been disappointing, and future research in this area will have to more precisely identify the most important mechanisms and actors in the immunopathogenesis of chronic HF in order to develop better immunomodulating agents for this disorder.

Myocardial expression of CC- and CXC-chemokines and their receptors in human end-stage heart failure

OBJECTIVES Chemokines regulate several biological processes, such as chemotaxis, collagen turnover, angiogenesis and apoptosis. Based on the persistent immune activation with elevated circulating levels of chemokines in patients with congestive heart failure (CHF), we have hypothesised a pathogenic role for chemokines in the development of CHF. The objective of this study was to examine mRNA levels and cellular localisation of chemokines and chemokine receptors in human CHF. METHODS We examined explanted hearts from ten patients with end-stage heart failure (all chambers) and in ten organ donors using an RNase protection assays and immunohistochemical techniques. RESULTS Our main findings were: (i) expression of eight chemokine and nine chemokine receptor genes in both failing and nonfailing myocardium, (ii) particularly high mRNA levels of monocyte chemoattractant protein (MCP)-1 and CXC-chemokine receptor 4 (CXCR4), in both chronic failing and nonfailing myocardium, (iii) decreased mRNA levels of MCP-1 and interleukin (IL)-8 in the failing left ventricles compared to failing left atria, (iv) decreased chemokine (e.g., MCP-1 and IL-8) and increased chemokine receptor (e.g., CCR2, CXCR1) mRNA levels in failing left ventricles and failing left atria compared to corresponding chambers in the nonfailing hearts and (v) immunolocalisation of MCP-1, IL-8 and CXCR4 to cardiomyocytes. CONCLUSION The present study demonstrates for the first time chemokine and chemokine receptor gene expression and protein localisation in the human myocardium, introducing a new family of mediators with potentially important effects on the myocardium. The observation of chemokine dysregulation in human end-stage heart failure may represent a previously unknown mechanism involved in progression of chronic heart failure.

CXC-chemokines, a new group of cytokines in congestive heart failure — possible role of platelets and monocytes

OBJECTIVES The purpose of the present study was to examine the circulating levels of CXC-chemokines in patients with various degree of congestive heart failure (CHF). BACKGROUND CXC-chemokines may be important mediators in the persistent immune activation observed in CHF patients by activation of circulating neutrophils, T-cells and monocytes and possibly by the recruitment of these cells into the failing myocardium. METHODS Levels of interleukin (IL)-8, growth-regulated oncogene (GRO) alpha and epithelial neutrophil activating peptide (ENA)-78 were measured both in serum and in platelet-free plasma by enzyme immunoassay in 47 patients with CHF and in 20 healthy controls. RESULTS (i) CHF patients had significantly elevated levels of all the three CXC-chemokines with IL-8 and GRO alpha showing a gradual increase along with increasing NYHA class. (ii) There was an inverse correlation between IL-8 and left ventricular ejection fraction (EF) and cardiac index (CI). (iii) Both unstimulated and lipopolysaccharide (LPS)-stimulated monocytes from CHF patients released markedly elevated amounts of all three CXC-chemokines. (iv) Platelets from patients with severe CHF were characterised by decreased content of GRO alpha and ENA-78 as well as decreased release of these chemokines upon thrombin receptor stimulation. (v) Activated platelets stimulated peripheral blood mononuclear cells in vitro to enhanced release of IL-8, and neutralising antibodies against ENA-78 inhibited this interaction. CONCLUSIONS This study demonstrates for the first time elevated levels of CXC-chemokines in CHF, which may be of importance for progression of heart failure. Our findings further suggest that activated monocytes and platelets may contribute to enhanced CXC-chemokine levels in CHF.

Chemokines and Cardiovascular Risk

Based on the importance of inflammation in atherogenesis, recent work has focused on whether plasma markers of inflammation can noninvasively diagnose and prognosticate atherosclerotic disorders. Although several studies support an important pathogenic role of chemokines in atherosclerosis, potentially representing attractive therapeutic targets in atherosclerotic disorders, this does not necessarily mean that chemokines are suitable parameters for risk prediction. In fact, the ability to reflect upstream inflammatory activity, stable levels in individuals, and high stability of the actual protein (eg, long half-life and negligible circadian variation) are additional important criteria for an ideal biomarker in cardiovascular disease. Although plasma/serum levels of certain chemokines (eg, interleukin- 8/CXCL8 and monocyte chemoattractant protein-1/CCL2) have shown to be predictive for future cardiac events in some studies, their role as clinical biomarkers is unclear, and their ability to predict subclinical atherosclerosis has been disappointing. Further prospective studies, including a larger number of patients, are needed to make any firm conclusion. Based on the participation of several chemokines in atherogenesis, it is possible that in the future, combined measurements of multiple chemokines could reveal as a “signature of disease” that can serve as a highly accurate method to assess for the presence of atherosclerotic disease.

Role of inflammation in the progression of heart failure.

Chronic heart failure (HF) is a disorder characterized in part by immune activation and inflammation. Thus, patients with HF have elevated levels of a number of inflammatory cytokines, both in the circulation and in the failing heart itself. Several mechanisms for this immune activation, which are not mutually exclusive, have been suggested, including neurohormonal activation, hemodynamic overload, and activation of the innate immune system secondary to cardiac stress. Importantly, experimental studies have shown that inflammatory cytokines such as tumor necrosis factor-α, interleukin-1β, and monocyte chemoattractant peptide-1 may contribute to the development and progression of HF by promoting myocardial hypertrophy, activating matrix metalloproteinases, provoking contractile dysfunction, and inducing apoptosis. However, inflammatory cytokines may also have adaptive and cardioprotective effects. This important aspect of cytokine biology must be kept in mind when designing new immunomodulatory treatment modalities in HF.

Systemic inflammatory markers in COPD: results from the Bergen COPD Cohort Study

Chronic obstructive pulmonary disease (COPD) is considered an inflammatory pulmonary disorder with systemic inflammatory manifestations. The aim of this study was to assess the systemic levels of six inflammatory mediators in a large cohort of COPD patients and controls. 409 COPD patients and 231 healthy subjects, aged 40–75 yrs, were included from the first phase of the Bergen COPD Cohort Study. All COPD patients were clinically diagnosed by a physician, and had a forced expiratory volume in 1 s/forced vital capacity ratio less than 0.7 and a smoking history of >10 pack-yrs. The plasma levels of C-reactive protein (CRP), soluble tumour necrosis factor receptor (sTNFR)-1, osteoprotegrin, neutrophil activating peptide-2, CXCL16 and monocyte chemoattractant protein-4 were determined by ELISA. After adjustment for all known confounders, COPD patients had significantly lower levels of osteoprotegrin than subjects without COPD (p<0.05), and higher levels of CRP (p<0.01). Among COPD patients, CRP was elevated in patients with frequent exacerbations (p<0.05). sTNFR-1 and osteoprotegrin were both related to Global Initiative for Chronic Obstructive Lung Disease stage and frequency of exacerbations in the last 12 months (p<0.05). In addition, sTNFR-1 was significantly associated with important comorbidities such as hypertension and depression (p<0.05). The present study confirms that certain circulating inflammatory mediators are an important phenotypic feature of COPD.

Enhanced gene expression of chemokines and their corresponding receptors in mononuclear blood cells in chronic heart failure—modulatory effect of intravenous immunoglobulin ☆

OBJECTIVES We sought to study the gene expression of chemokines and their corresponding receptors in mononuclear blood cells (MNCs) from patients with chronic heart failure (CHF), both of which were cross-sectional and longitudinal studies during therapy with intravenous immunoglobulin (IVIg). BACKGROUND We have recently demonstrated that IVIg improves left ventricular ejection fraction (LVEF) in patients with CHF. Based on the potential pathogenic role of chemokines in CHF, we hypothesized that the beneficial effect of IVIg may be related to a modulatory, effect on the expression of chemokines and their receptors in MNCs. METHODS We examined: 1) the gene expression of C, CC and CXC chemokines and their receptors in MNCs from 20 patients with CHF and 10 healthy blood donors; and 2) the expression of these genes in MNCs from 20 patients with CHF randomized in a double-blind fashion to therapy with IVIg or placebo for 26 weeks. RESULTS Our main findings in CHF were: 1) markedly raised gene expression of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and interleukin (IL)-8; 2) enhanced gene expression of their corresponding receptors; 3) modulation in a normal direction of this abnormal chemokine and chemokine receptor gene expression during IVIg, but not during placebo therapy; 4) down-regulation of MIP-1alpha, MIP-1beta and IL-8 during IVIg at the protein level in plasma; and 5) a correlation between down-regulation of MIP-1alpha gene expression and improved LVEF during IVIg therapy. CONCLUSIONS Our results further support a pathogenic role for chemokines in CHF and suggest that IVIg may represent a novel therapeutic approach, with the potential to improve LVEF in patients with CHF, possibly by modulatory effects on the chemokine network.

C-reactive protein, infarct size, microvascular obstruction, and left-ventricular remodelling following acute myocardial infarction

AIMS This study assessed the relationship between inflammatory mediators and indices of infarct size and left-ventricular (LV) remodelling following successful primary percutaneous coronary intervention (PCI) in patients with first time ST elevation myocardial infarction (MI). METHODS AND RESULTS Forty-two patients admitted with an occluded single vessel were recruited consecutively. Cardiac magnetic resonance was used for serial assessment (2 days, 1 week, 2 months) of infarct size, microvascular obstruction (MO), and LV remodelling. Inflammatory mediators were analysed before and after PCI. Our major findings were: (1) Following PCI, there was a marked increase in plasma levels of C-reactive protein, closely correlated with an increase in interleukin-6 and terminal complement complex, reaching maximum 2 days after PCI; (2) C-reactive protein 2 days after PCI was significantly correlated with infarct size and parameters of LV remodelling 2 months after PCI; (3) Patients with persistent MO had significantly higher C-reactive protein levels 2 days following PCI. CONCLUSION We suggest that the rapid increase in C-reactive protein levels in this model of successful revascularization of a single, totally occluded vessel reflects the degree of inflammation within the infarcted area. Our findings support a role for C-reactive protein-mediated complement activation as both a marker and mediator of myocardial damage following MI. Clinical study no.: NCT 00465868.

Inflammatory imbalance between IL-10 and TNFα in unstable angina potential plaque stabilizing effects of IL-10

Background The pathogenesis of atherosclerosis and acute coronary syndromes involves inflammation and immunological mechanisms. We hypothesized that patients with unstable angina may have an imbalance between inflammatory and anti‐inflammatory cytokines.