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Biomedical subjects

Pål Aukrust

Publications and source records attributed to Pål Aukrust.

At least 19 recordsLinked to original sources
PubMed2006

Increased levels of neutrophil-activating peptide-2 in acute coronary syndromes: possible role of platelet-mediated vascular inflammation.

OBJECTIVES: We sought to investigate the role of the CXC chemokine neutrophil-activating peptide-2 (NAP-2) in atherogenesis and plaque destabilization. BACKGROUND: Chemokines are involved in atherogenesis, but the role of NAP-2 in atherosclerotic disorders is unclear. Based on its potential pro-atherogenic properties, we hypothesized a pathogenic role for NAP-2 in coronary artery disease. METHODS: We tested this hypothesis by differential experimental approaches including studies in patients with stable (n = 40) and unstable angina (n = 40) and healthy control subjects (n = 20). RESULTS: The following results were discovered: 1) patients with stable, and particularly those with unstable, angina had markedly raised plasma levels of NAP-2 compared with control subjects, accompanied by increased expression of CXC receptor 2 in monocytes; 2) platelets, but also peripheral blood mononuclear cells (PBMCs), released large amounts of NAP-2 upon stimulation, with a particularly prominent PBMC response in unstable angina; 3) NAP-2 protein was detected in macrophages and smooth muscle cells of atherosclerotic plaques and in monocytes and platelets of coronary thrombi; 4) in vitro, recombinant and platelet-derived NAP-2 increased the expression of adhesion molecules and chemokines in endothelial cells; and 5) whereas aspirin reduced plasma levels of NAP-2, statin therapy increased NAP-2 with stimulating effects both on platelets and leukocytes. CONCLUSIONS: Our findings suggest that NAP-2 has the potential to induce inflammatory responses within the atherosclerotic plaque. By its ability to promote leukocyte and endothelial cell activation, such a NAP-2-driven inflammation could promote plaque rupture and acute coronary syndromes.

Acute Disease↗
PubMed2006

Increased levels of soluble CD40L in African tick bite fever: possible involvement of TLRs in the pathogenic interaction between Rickettsia africae, endothelial cells, and platelets.

The pathophysiological hallmark of spotted fever group rickettsioses comprises infection of endothelial cells with subsequent infiltration of inflammatory cells. Based on its ability to promote inflammation and endothelial cell activation, we investigated the role of CD40L in African tick bite fever (ATBF), caused by Rickettsia africae, using different experimental approaches. Several significant findings were revealed. 1) Patients with ATBF (n = 15) had increased serum levels of soluble CD40 ligand (sCD40L), which decreased during follow-up. 2) These enhanced sCD40L levels seem to reflect both direct and indirect (through endothelial cell activation involving CX3CL1-related mechanisms) effects of R. africae on platelets. 3) In combination with sCD40L, R. africae promoted a procoagulant state in endothelial cells by up-regulating tissue factor and down-regulating thrombomodulin expression. 4) Although the R. africae-mediated activation of platelets involved TLR2, the combined procoagulant effects of R. africae and sCD40L on endothelial cells involved TLR4. 5) Doxycycline counteracted the combined procoagulant effects of R. africae and sCD40L on endothelial cells. Our findings suggest an inflammatory interaction between platelets and endothelial cells in ATBF, involving TLR-related mechanisms. This interaction, which includes additive effects between sCD40L and R. africae, may contribute to endothelial inflammation and hypercoagulation in this disorder.

Adult↗
PubMed2006

The role of intravenous immunoglobulin in the treatment of chronic heart failure.

Chronic heart failure (HF), including both ischemic and idiopathic dilated cardiomyopathies, is accompanied by a dysregulated cytokine network characterized not only by a rise in inflammatory cytokines, but also by an inadequate elevation of anti-inflammatory mediators. This dysregulation has been implicated in the development and progression of chronic HF, and in the last decade, attempts have been made to modulate this persistent inflammation. Failure of anti-tumor necrosis factor therapy in HF has led to further interest in a more general immunomodulatory approach, directed against the inflammatory imbalance rather than one particular cytokine. Treatment with intravenous immunoglobulin (IVIg) may represent such a broad-based approach trying to restore the dysregulated cytokine network through various mechanisms such as Fc receptor blockade, neutralization of microbial antigens and superantigens and more direct anti-inflammatory effects on the cytokine network. However, although one randomized placebo-controlled study in patients with chronic HF showed that IVIg improved left ventricular ejection fraction, accompanied by anti-inflammatory net effects, IVIg had no effect in another placebo-controlled study examining the effect of this medication in recent-onset cardiomyopathy. So far, few patients have been included in clinical trials, and there is clearly a need for larger placebo-controlled mortality studies involving a diverse group of patients with regard to cause and severity of HF.

Autoantibodies↗
PubMed2006

Platelet-derived LIGHT induces inflammatory responses in endothelial cells and monocytes.

Traditionally, platelets are known to play an important role in hemostasis, thrombosis, and wound healing, but increasing evidence suggests that activated platelets also may promote inflammation. Platelet-induced modulation of inflammation seems to involve platelet expression of ligands in the tumor necrosis factor (TNF) superfamily such as CD40 ligand and Fas ligand. The present study demonstrates that LIGHT, another member of the TNF superfamily, is associated with platelets and is released as a soluble ligand on platelet activation. The release of LIGHT involves GP IIb/IIIa-dependent mechanisms and action of metal-dependent proteases as well as intracellular processes such as actin polymerization. We also report that platelet-derived LIGHT is biologically active and can induce an inflammatory response in monocytes and particularly within endothelial cells measured as up-regulation of adhesion molecules and release of chemokines. Moreover, we demonstrate that thrombus material, obtained at the site of plaque rupture in patients with acute myocardial infarction, contains platelet-associated LIGHT, suggesting that LIGHT-mediated inflammation also is operating in vivo within an inflamed and thrombotic vessel wall. The data may suggest a pathogenic role for platelet-derived LIGHT in atherogenesis and plaque destabilization as well as in other inflammatory disorders involving leukocyte infiltration into the vessel wall.

Blood Platelets↗
PubMed2006

Decreased endomyocardial RANKL expression in transplant coronary artery disease.

Transplant-associated coronary artery disease (TxCAD) appears to be initiated by endothelial cell activation and inflammation involving inflammatory cytokines and chemokines. Osteoprotegerin (OPG) and receptor activator of nuclear Factor-kappaB ligand (RANKL) have been implicated in cardiovascular disease progression and we measured the expression of these mediators in serum and myocardial biopsies taken serially during the first year after heart transplantation (HTx), relating them to the development of TxCAD. Serum OPG as well as myocardial gene expression of RANK and OPG, but not RANKL, were highest early after HTx and declined progressively. Importantly, patients who develop TxCAD or experience episodes of acute rejection showed a lower myocardial RANKL expression throughout the first year after transplantation than patients without these complications. Our findings may suggest an unrecognized role RANKL in maintaining myocardial and/or endothelial integrity and suggest that RANKL should be further investigated as a parameter that may predict development of TxCAD.

Adolescent↗
PubMed2006

Impaired inhibitory effect of interleukin-10 on the balance between matrix metalloproteinase-9 and its inhibitor in mononuclear cells from hyperhomocysteinemic subjects.

BACKGROUND AND PURPOSE: Homocysteine has been linked to increased risk of ischemic stroke and other cardiovascular events, but the mechanism by which elevated plasma levels of homocysteine promotes atherogenesis remains unclear. Matrix degradation, partly regulated by the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs), plays an important role in atherogenesis and plaque destabilization, and we hypothesized an imbalance between MMPs and TIMPs in hyperhomocysteinemia. METHODS: Serum MMP-9 and TIMP-1 was measured in 12 hyperhomocysteinemic and 12 control subjects. The release of MMP-9 and TIMP-1, with and without interleukin-10 (IL-10), and the effect of IL-10 on signal transducer and activator of transcription 3 (STAT3) phosphorylation were measured in peripheral blood mononuclear cells (PBMCs) from hyperhomocysteinemic and control subjects. RESULTS: Our main findings were: (1) hyperhomocysteinemic subjects had raised serum levels of MMP-9 and MMP-9/TIMP-1 ratio comparing healthy controls; (2) although IL-10 markedly suppressed MMP-9 release from PBMCs in controls, no or only minor effect was seen in hyperhomocysteinemic subjects; (3) although IL-10 enhanced TIMP-1 levels in PBMCs from both hyperhomocysteinemic and control subjects, the increase was more prominent in controls, resulting in a marked difference in IL-10-induced changes in MMP-9/TIMP-1 ratio between these 2 groups; and (4) comparing PBMCs from controls, cells from hyperhomocysteinemic individuals had impaired IL-10-induced STAT3 phosphorylation. CONCLUSIONS: Our findings suggest an attenuated inhibitory response to IL-10 on MMP-9 activity in hyperhomocysteinemic subjects, potentially promoting atherogenesis and plaque instability, representing a novel explanation for increased risk for atherosclerotic disease in these individuals.

Adult↗
PubMed2006

Immune modulatory effects of cyclooxygenase type 2 inhibitors in HIV patients on combination antiretroviral treatment.

OBJECTIVES: To examine the immune modulating effects of cyclooxygenase type 2 (COX-2) inhibitors (COX-2i) in HIV-infected patients on combination antiretroviral treatment (CART). DESIGN: In-depth substudy from an approved, open, controlled, randomized study comparing the immune modulating effects of CART in combination with COX-2i after 12 weeks. METHODS: Patients (n = 38) on long-term CART with stable viral load (VL) < 50,000 copies/ml and CD4+ T-cell counts > 100/microl were randomized to CART and rofecoxib 25 mg bid (n = 12) or celecoxib 400 mg bid (n = 12), or CART only without placebo (n = 14). Routine clinical chemistry, CD4+ and CD8+ counts and VL were safety parameters. Immunological parameters included C-reactive protein, beta2-microglobulin, Ig isotypes and IgG subclasses as well as several T-lymphocyte subsets. Non-parametric analyses were used throughout. RESULTS: Prestudy experiments showed higher median intracellular expression of COX-2 in CD4+ (P = 0.048) and possibly CD8+ (P = 0.09) T cells from patients on CART compared with uninfected controls. In the clinical study, increased CD4+ T-cell counts were observed only in patients on COX-2i with VL < 50 copies/ml (P = 0.02). Decreased expression of CD38+ on CD8+ T cells and subsets as well as reductions in IgA and IgM (P < 0.03) were most pronounced in patients on COX-2i who had detectable VL (n = 6). COX-2i treatment enhanced the perforin content particularly in the differentiated CD27-/CD8+ T-cell subsets compared with controls (P = 0.05). CONCLUSIONS: COX-2i together with CART improved markers for persistent immune activation, particularly in patients with viraemia, as well as enhanced perforin expression, and thereby strengthened COX-2 as a potential therapeutic target in HIV infection.

ADP-ribosyl Cyclase 1↗
PubMed2006

Systemic inflammation in nonalcoholic fatty liver disease is characterized by elevated levels of CCL2.

BACKGROUND/AIMS: To elucidate the role of systemic inflammation in nonalcoholic fatty liver disease (NAFLD). METHODS: Serum samples in 47 patients with histologically verified NAFLD (22 with simple steatosis and 25 with nonalcoholic steatohepatitis [NASH]), and in 30 age-, sex- and ethnicity-matched healthy controls, were assessed for (i) general markers of inflammation (C-reactive protein [CRP], tumor necrosis factor [TNF]-alpha, and interleukin [IL]-6), (ii) chemokines (CC-chemokine ligand [CCL] 2/monocyte chemoattractant protein [MCP]-1, CCL19 and CCL21), (iii) adipocytokines related to insulin resistance and inflammation (adiponectin and leptin) and (iv) a marker of oxidative stress (8-isoprostane-F2alpha). RESULTS: Serum levels of several inflammatory cytokines were increased in NAFLD as compared to controls, and IL-6 (P=0.017), CCL2/MCP-1 (P=0.008) and CCL19 (P=0.001), but not CRP (P=0.199), remained elevated also after correction for sex, body mass index (BMI) and age. Comparing NASH with simple steatosis, levels of TNF-alpha (P=0.024) and CCL2/MCP-1 (P=0.012) were elevated and adiponectin (in women) (P=0.001) were decreased also after adjustment for sex, BMI and presence of the metabolic syndrome. CONCLUSIONS: Our results indicate that patients with NAFLD are characterized by a low-grade systemic inflammation. The high CCL2/MCP-1 levels in NASH might be of importance for the conversion from simple steatosis to NASH.

Adult↗
PubMed2006

Thalidomide attenuates the development of fibrosis during post-infarction myocardial remodelling in rats.

BACKGROUND: Inflammation plays a pathogenic role in the development of heart failure (HF). The aim of this study was to examine the effect of treatment with the immunomodulating drug thalidomide in a rat model for post-myocardial infarction (MI) HF. METHODS: Rats were subjected to MI by left coronary artery ligation or sham-operated. Seven days after surgical intervention rats were randomised to treatment with thalidomide or vehicle for 8 weeks. RESULTS: Our main findings were: (i) thalidomide treatment did not affect cardiac function or the hypertrophic response, as determined by haemodynamic measurements and heart chamber weights, respectively. (ii) HF rats treated with thalidomide had a minor reduction in septum and relative wall thickness (p<0.05), indicating an anti-remodelling effect. (iii) Thalidomide appeared to have immunostimulatory effects on the myocardium as evident by increased MIP-1alpha gene expression (p<0.05). (iv) Treating HF rats with thalidomide reduced myocardial collagen content, as assessed by markedly decreased levels of hydroxyproline ( approximately 40% reduction; p<0.05), accompanied by lower TGF-beta(1) gene expression (p<0.05). CONCLUSION: Although thalidomide had no effect on cardiac function, our results suggest that intervention with thalidomide may have beneficial effects in post-MI HF by attenuating collagen accumulation and development of myocardial fibrosis.

Animals↗
PubMed2006

Enhanced T-cell expression of RANK ligand in acute coronary syndrome: possible role in plaque destabilization.

OBJECTIVE: Based on its role in inflammation and matrix degradation, we hypothesized a role for osteoprotegerin (OPG), RANK, and RANK ligand (RANKL) in coronary artery disease. METHODS AND RESULTS: We examined the expression of various members of the OPG/RANKL/RANK axis in patients with stable and unstable angina and in the atherosclerotic lesions of apolipoprotein E-deficient (apoE(-/-)) mice. Our findings were: (1) Serum levels of OPG were raised in patients with unstable angina (n=40), but not in those with stable angina (n=40), comparing controls (n=20); (2) mRNA levels of RANKL were increased in T-cells in unstable angina patients accompanied by increased expression of RANK in monocytes; (3) strong immunostaining of OPG/RANKL/RANK was seen within thrombus material obtained at the site of plaque rupture during acute myocardial infarction; (4) OPG/RANKL/RANK was expressed in the atherosclerotic plaques of apoE(-/-) mice, with RANKL located specifically to the plaques; and (5) RANKL enhanced the release of monocyte chemoattractant peptide-1 in mononuclear cells from unstable angina patients, and promoted matrix metalloproteinase (MMP) activity in vascular smooth muscle cells. CONCLUSIONS: We show enhanced expression of the OPG/RANKL/RANK system both in clinical and experimental atherosclerosis, with enhanced T-cell expression of RANKL as an important feature of unstable disease.

Adult↗
PubMed2006

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.

Anemia↗
PubMed2006

Mannose binding lectin and soluble Toll-like receptor 2 in heart failure following acute myocardial infarction.

BACKGROUND: To determine the relationship between markers of innate immunity and clinical outcomes in patients with heart failure (HF) after acute myocardial infarction (AMI). Atherogenesis and HF is associated with the altered control of inflammation by innate immune defenses that include pattern-recognition molecules such as Toll-like receptors (TLRs) and mannose-binding lectin (MBL). METHODS AND RESULTS: We assessed circulating levels, and relationships with adverse outcomes of MBL and sTLR2 levels in 234 patients with AMI complicated with HF. Blood was sampled at baseline (median 3 days after AMI), 1 month, 1 year, and 2 years. For comparison, we also measured MBL and sTLR2 levels in 20 age- and sex-matched healthy controls. Patients with post-MI HF had markedly decreased serum levels of sTLR2 at baseline that increased during follow-up, but did not reach the concentrations present in healthy controls. In contrast, serum MBL levels were initially normal in patients with post-MI HF, but decreased during follow-up, and MBL levels measured 1 month after the index infarct were inversely associated with a higher incidence of reinfarction. CONCLUSION: These findings suggest that circulating levels of MBL and sTLR2 may reflect different aspects of the innate immune response and further suggest the involvement of innate immunity responses in the pathogenesis of post-MI HF.

Aged↗
PubMed2006

Anti-inflammatory trials in chronic heart failure.

Chronic heart failure (CHF) is accompanied by a dysregulated cytokine network, which is characterized by a rise in inflammatory cytokines and an inadequate elevation of anti-inflammatory mediators. This dysregulation has been implicated in the development and progression of CHF and, in the last decade, attempts have been made to modulate this imbalance in the cytokine network. With the exception of one larger mortality/morbidity study, all studies of immunomodulatory therapy in HF conducted to date have included <100 patients and the overall experience in this therapeutic area is limited compared with studies of neurohormonal antagonists, which have included several thousand patients. While trials of anti-tumor necrosis factor therapies have thus far failed, recent studies of broad-based immunomodulatory agents (e.g. intravenous immunoglobulin, thalidomide, and pentoxifylline) highlight a potential for such therapy in HF patients, in parallel with optimal cardiovascular treatment regimens. In addition to identifying the crucial factors in the immunopathogenesis of CHF in order to develop novel immunomodulatory treatment strategies, there is a clear need to confirm the results of the smaller studies conducted to date with larger placebo-controlled mortality studies that involve a diverse group of patients, with regard to the cause and severity of HF.

Adult↗
PubMed2005

Effect of thalidomide on cardiac remodeling in chronic heart failure: results of a double-blind, placebo-controlled study.

BACKGROUND: Inflammation and matrix degradation may play a pathogenic role in chronic heart failure (CHF), and therefore, we examined whether thalidomide, a drug with potential immunomodulating and matrix-stabilizing properties, could improve left ventricular (LV) function in patients with CHF secondary to idiopathic dilated cardiomyopathy (IDCM) or coronary artery disease (CAD). METHODS AND RESULTS: Fifty-six patients with CHF and an LV ejection fraction (LVEF) <40% who were already on optimal conventional cardiovascular treatment were randomized to thalidomide (25 mg QD increasing to 200 mg QD) or placebo and followed up for 12 weeks. Our main findings were as follows: (1) During thalidomide treatment but not during placebo, there was a marked increase in LVEF (&7 EF units) along with a significant decrease in LV end-diastolic volume and heart rate. (2) This improvement in LVEF was accompanied by a decrease in matrix metalloproteinase-2 without any changes in its endogenous tissue inhibitor, suggesting a matrix-stabilizing net effect. (3) Thalidomide also induced a decrease in total neutrophil count and an increase in plasma levels of tumor necrosis factor-alpha, suggesting both proinflammatory and antiinflammatory effects. (4) The effect of thalidomide on LVEF was more marked in IDCM than in CAD, possibly partly reflecting that the former group was able to tolerate a higher thalidomide dosage. CONCLUSIONS: Although our results must be confirmed in larger studies that also examine the effects on morbidity and mortality, our findings suggest a role for thalidomide in the management of CHF in addition to traditional cardiovascular medications.

Aged↗
PubMed2005

Plasma levels of soluble tumor necrosis factor receptor type I during the acute phase following complicated myocardial infarction predicts survival in high-risk patients.

OBJECTIVES: We sought to determine the relationship between circulating cytokine levels and clinical outcomes in patients with heart failure (HF) following acute myocardial infarction (AMI). BACKGROUND: Persistent inflammation plays a role in the development of HF, and various inflammatory cytokines predict cardiovascular events in acute coronary syndromes. METHODS: We measured plasma levels of interleukin (IL)-6, monocyte chemotractant protein 1, IL-10, and soluble tumor necrosis factor receptor type 1 (sTNFR1) during longitudinal testing over a period of two years in 234 patients with HF following AMI recruited for participation in the OPTIMAAL trial, focusing on the possible prognostic value of circulating cytokine levels in these patients. RESULTS: Measurement of sTNFR1 at baseline predicted all-cause mortality and cardiovascular death in patients with post-MI HF after adjustment for other biomarkers that have been shown to give prognostic information in HF patients, such as N-terminal B-type natriuretic peptide. CONCLUSIONS: Assessment of sTNFR1 levels might provide important prognostic information in patients who develop HF during the acute phase following AMI.

Aged↗
PubMed2005

Chemokines in children with heterozygous familiar hypercholesterolemia: selective upregulation of RANTES.

OBJECTIVE: Increasing data support the involvement of chemokines in atherogenesis. However, although several studies have shown increased chemokine levels in adult patients, the literature is virtually devoid of data on chemokines in children with hypercholesterolemia. METHODS AND RESULTS: We examined the gene expression of chemokines in peripheral blood mononuclear cells (PBMCs) from clinically healthy children with and without heterozygous familial hypercholesterolemia (FH). Our main findings were: (1) compared with healthy controls, PBMCs from FH children showed significantly higher mRNA levels of RANTES, but not of the other examined chemokines; (2) an opposite pattern was seen in adult FH subjects, with markedly enhanced expression of macrophage inflammatory peptide-1alpha, but not of RANTES; (3) this increased gene expression of RANTES in PBMCs from FH children seemed to reflect enhanced RANTES expression in monocytes but not in T cells; (4) FH children also had raised serum levels of neopterin, additionally suggesting monocyte/macrophage activation in these children; and (5) PBMCs from both FH children and controls showed enhanced release of interleukin 8 on RANTES stimulation in vitro. CONCLUSIONS: Our findings support a role of inflammation also in the early stages of atherogenesis possibly involving monocyte-derived RANTES as an important mediator.

Adolescent↗