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Biomedical subjects

P Aukrust

Publications and source records attributed to P Aukrust.

At least 37 records · Page 2Linked to original sources

Immunomodulating effects of 3-thia fatty acids in activated peripheral blood mononuclear cells.

BACKGROUND: 3-thia fatty acids such as tetradecylthioacetic acid (TTA) are modified fatty acids that have been suggested to change the plasma profile from atherogenic to cardio protective. Because of its interaction with peroxisome proliferator activated receptor (PPAR) we hypothesized that TTA also could have immunomodulatory properties. Based on the suggested role of inflammation in atherogenesis, any immunomodulating effects of TTA would be of particular interest for the potential use of this fatty acid in atherosclerotic disorders. MATERIALS AND METHODS: We examined if TTA could modulate proliferation and the release of cytokines from peripheral mononuclear cells (PBMCs) taken from five healthy blood donors. RESULTS: Our main findings were: (i) TTA had several effects on cytokine release from activated PBMCs with a marked increase in interleukin (IL)-10 accompanied by a reduction in IL-2 possibly favouring anti-inflammatory net effects. (ii) These cytokine-modifying effects were found in both T cells and monocytes when cultured separately. (iii) Tetradecylthioacetic acid increased the cytokine stimulating effects of tumour necrosis factor alpha with a particularly enhancing effect on IL-10. (iv) Tetradecylthioacetic acid significantly suppressed PBMC proliferation, and this antiproliferative property did not involve enhanced apoptosis or necrosis. (v) These immunomodulatory effects of TTA were accompanied by a marked down-regulation of PPARoad mRNA expression, the most abundant PPAR subtype in PBMCs. CONCLUSIONS: Our findings show potent immunomodulatory effects of TTA in activated PBMCs, possibly involving PPAR-related mechanisms.

Adult↗

Expression of matrix metalloproteinase-9 in mononuclear cells of hyperhomocysteinaemic subjects.

Atherosclerotic plaque instability and rupture requires extracellular matrix modification, a complex process regulated by matrix metalloproteinases (MMPs). We hypothesized that homocysteine's atherogenic effects may involve MMP-mediated mechanisms. Our results showed the following: (i) Compared with healthy control subjects (n = 9), patients with hyperhomocysteinaemia (n = 9) had elevated mRNA levels of MMP-9 and tissue inhibitors of metalloproteinases-1 (TIMP-1) in freshly isolated peripheral blood mononuclear cells (PBMCs), which were positively correlated with homocysteine and negatively correlated with folate and vitamin B12 levels. (ii) Peripheral blood mononuclear cells obtained from these patients released markedly enhanced the amount of MMP-9 upon oxidized LDL (oxLDL) stimulation, whereas no such enhancing effect was seen in cells from healthy controls. (iii) During folic acid 6 weeks' treatment, normalization of homocysteine levels was accompanied by a significant reduction in mRNA levels of MMP-9 and TIMP-1 in PBMCs, as well as a marked reduction in oxLDL-stimulated release of MMP enzyme activity. These novel findings may suggest that homocysteine exerts its atherogenic effect in part by elevating levels and activity of MMPs, which in turn may enhance matrix degradation, potentially promoting atherogenesis and plaque instability. Moreover, our findings suggest that folic acid supplementation may down-regulate these inappropriate responses in these patients.

Female↗

CXC-chemokines in coronary artery disease: possible pathogenic role of interactions between oxidized low-density lipoprotein, platelets and peripheral blood mononuclear cells.

CXC-chemokines may be involved in atherogenesis. Herein we examined the possible role of CXC-chemokines in the inflammatory interactions between oxidized (ox-) low-density lipoprotein (LDL), platelets and peripheral blood mononuclear cells (PBMC) in 15 patients with coronary artery disease (CAD) without 'traditional' risk factors and 15 carefully matched controls. Our main findings were: (a) ox-LDL stimulated the release of the CXC-chemokines interleukin (IL)-8, ENA-78 and GRO-alpha from PBMC, particularly in CAD. (b) In platelets, ox-LDL induced release of ENA-78 and, when combined with SFLLRN, also of GRO-alpha, with significantly higher response in CAD. (c) Platelet-rich plasma, especially when costimulated with ox-LDL, enhanced the release of IL-8 from PBMC, particularly in CAD patients. (d) Freshly isolated PBMC showed markedly increased IL-8 mRNA expression in CAD patients. Our findings suggest enhanced inflammatory interactions between ox-LDL, platelets and PBMC in CAD patients involving CXC-chemokine related mechanisms, possible contributing to atherogenesis in these and other CAD patients.

Adult↗

Interleukin-1 receptor antagonist is associated with fat distribution in endogenous Cushing's syndrome: a longitudinal study.

The weight gain and visceral obesity associated with Cushing's syndrome (CS) has been linked to elevated plasma leptin levels, although the mechanism behind a central leptin resistance in these patients is unknown. Several studies describe interactions among the hypothalamic-pituitary-adrenal axis, leptin, and the IL-1 system. To investigate these interactions, we have evaluated changes in regional fat distribution, by DEXA, and the role of circulating cortisol, leptin, IL-1beta, and IL-1 receptor antagonist (IL-1Ra), in relation to these changes, in 27 (19 DEXA; 27 serum measurements) patients with CS, before and after surgical treatment (mean follow-up, 31 months; range, 5-80), and compared them with measurements of age-, sex-, and body mass index-matched healthy controls (also obtained longitudinally). We found that surgical treatment caused a decrease in all fat parameters, without changing lean body mass, and these changes were significantly larger than the so-called natural changes occurring in control subjects. These changes in CS patients were paralleled by decreases in cortisol, leptin, and IL-1Ra, whereas IL-1beta increased. Stepwise linear regression showed that serum IL-1Ra was strongly associated with regional fat distribution, and especially truncal fat mass, both at baseline and during treatment. In conclusion, the present study shows that treatment significantly changes body composition in CS patients by decreasing fat mass, especially in the truncal region, without major effects on lean body mass. We also show that circulating IL-1Ra is strongly associated with these changes, signifying a relationship among the hypothalamic-pituitary-adrenal axis, IL-1 system, and regional fat distribution in these patients.

Adipose Tissue↗

Effects of interferon-alpha on gene expression of chemokines and members of the tumour necrosis factor superfamily in HIV-infected patients.

We examined the effect of interferon (IFN)-alpha on the expression of 375 genes relevant to inflammatory and immunological reactions in peripheral blood mononuclear cells (PBMC) from HIV-infected patients by cDNA expression array and real-time quantitative RT-PCR. Our main findings were: (i) IFN-alpha induced up-regulation of several genes in the tumour necrosis factor (TNF) superfamily including the ligands APRIL, FasL, TNF-alpha and TRAIL, with particularly enhancing effects on the latter in HIV-infected patients. (ii) While IFN-alpha markedly up-regulated the expression of anti-angionetic ELR- CXC-chemokines (e.g. MIG and IP-10), it suppressed the expression of angiogenic ELR+ CXC-chemokines (e.g. GRO-alpha, IL-8 and ENA-78), with similar patterns in both patients and controls. (iii) IFN-alpha induced a marked increase in gene expression of the HIV co-receptor CCR5 in both patients and controls. We suggest that these effects may contribute to both the therapeutic and toxic effects of IFN-alpha. Moreover, our findings underscore that the biological effects of IFN-alpha in HIV infection are complex and that the clinical net effects of IFN-alpha treatment may be difficult to predict. However, the potent enhancing effect of IFN-alpha on several pro-apoptotic genes in the TNF superfamily and the enhancing effect on CCR5 expression suggest a possible pathogenic role of IFN-alpha in the progression of HIV-related immunodeficiency and suggests caution in the therapeutic use of IFN-alpha in HIV-infected -individuals.

Adult↗

Immunophenotypic analyses of CD34(+) cell subsets in bone marrow from HIV-infected patients during highly- active antiretroviral therapy.

BACKGROUND: Because increased bone marrow lymphopoiesis might contribute to immunologic reconstitution during highly-active antiretroviral therapy (HAART), we examined the effect of HAART on CD34(+) cell subsets in bone marrow from HIV-infected patients. MATERIALS AND METHODS: In 12 HIV-infected patients, bone marrow and peripheral blood were collected before then 4 and 26 weeks after initiating HAART. Bone marrow in 28 HIV-seronegative controls was also examined. Immunophenotypic analyses of CD34(+) cell subsets in bone marrow were performed by flow cytometry. RESULTS: Our main findings in bone marrow were: (i) HIV-infected patients had increased proportions of CD34(+)cells expressing T- and B-cell markers before initiating HAART; (ii) in contrast, these patients had decreased proportions of CD34(+) cells expressing myeloid-associated markers; (iii) although HAART induced an increase in peripheral T-cell counts, the percentage of CD34(+)cells expressing T-cell markers tended to decrease during such therapy; (iv) HAART induced a decrease in serum IgG accompanied by a slight decrease in the proportion of CD34(+)cells expressing B-cell markers; (v) in contrast, HAART induced a significant increase in peripheral granulocyte counts, accompanied by a slightly increased proportion of CD34(+) cells expressing myeloid-associated molecules. CONCLUSION: Our findings are compatible with an HIV-related block in T-cell differentiation, leading to accumulation of T-cell progenitors in bone marrow, and such a block may be removed by HAART.

Adult↗

Inflammatory imbalance between IL-10 and TNFalpha 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. DESIGN: Plasma levels of tumour necrosis factor (TNF)alpha and interleukin (IL)-10 were analyzed in 44 patients with stable angina, 29 patients with unstable angina and 20 controls. mRNA levels of these cytokines were analyzed in peripheral blood mononuclear cells (PBMC). We also studied the in vitro effects of IL-10 in PBMC from unstable angina patients. RESULTS: Our main findings were: (1) the angina patients and particularly those with unstable disease had significantly raised TNFalpha in comparison with the controls, both at the protein and mRNA level; (2) in contrast, the levels of IL-10 were not different in the angina patients in comparison with the healthy controls, resulting in a markedly enhanced TNFalpha:IL-10 ratio, particularly in the unstable angina patients; (3) while exogenously added IL-10 markedly inhibited the release of TNFalpha, IL-8 and tissue factor as well as impairing the gelatinolytic activity and mRNA production of matrix metalloproteinase-9, it enhanced the tissue inhibitor of this metalloproteinase (i.e. TIMP-1) in PBMC from the unstable angina patients. CONCLUSION: Patients with unstable angina appear to have an imbalance between TNFalpha and IL-10, possibly favouring inflammatory net effects. IL-10 may have beneficial effects on mechanisms that are important in plaque rupture and thrombus formation.

Adult↗

Complement activation in patients with congestive heart failure: effect of high-dose intravenous immunoglobulin treatment.

BACKGROUND: Increasing evidence implicates innate immunity in the pathogenesis of congestive heart failure (CHF). In the present study, we examined the possible role of complement, an important part of innate immunity, in CHF. METHODS AND RESULTS: Complement activation was analyzed in systemic and coronary circulation in 39 patients with CHF and 20 healthy control subjects. In a double-blind, placebo-controlled study, we have recently reported that high-dose intravenous immunoglobulin (IVIG) improves left ventricular ejection fraction (LVEF) in these patients. To examine if this improvement was related to IVIG-induced effects on complement, we also examined complement activation during induction (first week) and maintenance therapy (6 months) with IVIG or placebo. Our main findings were: (1) We found enhanced systemic complement activation involving classic, alternative, as well as terminal pathway in patients with CHF compared with healthy control subjects. (2) Particularly enhanced complement activation was found in coronary sinus, representing venous drainage from the heart. (3) The systemic complement activation was further enhanced during IVIG but not during placebo therapy, particularly during induction therapy. (4) Although IVIG improved LVEF in patients with CHF, the degree of IVIG-mediated complement activation was negatively correlated with this improvement of LVEF. CONCLUSIONS: This study further supports the involvement of innate immunity in the pathogenesis of CHF. Our findings suggest that complement may be added to the list of possible therapeutic targets in CHF and that future studies with specific complement inhibitors may be of interest in this disorder.

C-Reactive Protein↗

Omega-3 fatty acids enhance tumor necrosis factor-alpha levels in heart transplant recipients.

BACKGROUND: Proinflammatory cytokines may contribute to clinical complications in heart transplant (HTx) recipients. Previous studies have shown immunomodulating effects of omega-3 fatty acids, but the results are somewhat conflicting. In this study, we examined plasma levels of tumor necrosis factor alpha (TNF-alpha), interleukin (IL) 10, and their relations to antioxidant vitamins in 45 HTx recipients before and after treatment with omega-3 fatty acids or placebo. METHODS: The patients were long-time survivors of heart transplantation, randomized in a double-blind fashion to receive omega-3 fatty acids (3.4 g/day) or placebo for 1 year. Plasma levels of cytokines were measured by enzyme immunoassays and vitamin A, vitamin E, and beta-carotene by high-performance liquid chromatography. RESULTS: In the omega-3, but not in the placebo group, there was a rise in the proinflammatory cytokine TNF-alpha (P<0.05), a decrease in the anti-inflammatory cytokine IL-10 (P=0.07), and a rise in TNF/IL-10 ratio (P<0.05) after 12 months, suggesting a proinflammatory net effect. In the omega-3 group, the increase in TNF-alpha was associated with an increase in eicosapentaenoic acid in plasma (r=0.58, P<0.02). During omega-3 fatty-acid treatment, but not during placebo, there was a decrease in vitamin E (P<0.05) and beta-carotene (P<0.05) levels, and the decrease in vitamin E was inversely correlated with the increase in TNF-alpha (r= -0.56, P<0.01). The rise in TNF-alpha levels during omega-3 fatty acids treatment was most pronounced in those patients with transplant coronary artery disease (P<0.04). CONCLUSION: Our data suggest that omega-3 fatty acids in HTx recipients may change the balance between proinflammatory and anti-inflammatory cytokines in an inflammatory direction, possibly related to prooxidative effects of these fatty acids.

Double-Blind Method↗

[Immunomodulating treatment in advanced heart failure--effect of intravenous immunoglobulin].

BACKGROUND: Congestive heart failure is characterised by enhanced immune activation. Immune-mediated mechanisms may play a pathogenic role, hence the growing interest in therapeutic regimens that could modulate the immune response in heart failure. MATERIAL AND METHODS: In the present report we discuss the pathogenic role of immunological and inflammatory mediators in the pathophysiology of heart failure and discuss different treatment modalities with focus on our recent study with intravenous immunoglobulin. In that study 40 patients with symptomatic chronic heart failure and left ventricular ejection fraction (LVEF) < 40% were randomised in a double-blind fashion to receive therapy with immunoglobulin or placebo for a total period of 26 weeks. RESULTS: We found that intravenous immunoglobulin, but not placebo, shifted the cytokine balance in an anti-inflammatory direction, and that such a shift was associated with improvement in LVEF by 5 EF units. Functional capacity and haemodynamic variables also improved. INTERPRETATION: Our study supports the hypothesis that immunological variables might be of significant importance in the pathogenesis of heart failure and it suggests a potential for immunomodulating therapy in addition to optimal conventional cardiovascular treatment regimens in such patients. These issues are further discussed in the present article.

Adjuvants, Immunologic↗

Complex effects of interferon-alpha on the cytokine network in HIV infection--possible contribution to immunosuppression.

Since interleukin (IL-)2, IL-10 and IL-12 may contribute to the pathogenesis of human immune deficiency virus (HIV) infection we examined the effect of interferon (IFN)-alpha on these cytokines in cultures of various subsets of peripheral blood mononuclear cells (PBMC) in ten HIV-infected patients and ten healthy controls. Our main findings were: (1) IFN-alpha markedly enhanced IL-10 levels in a dose-dependent manner in both lipopolysaccharide (LPS)- and phytohaemagglutinin (PHA)-stimulated PBMC, as well as in anti-CD3- and anti-CD3/anti-CD28-stimulated T cells in both HIV-infected patients and controls. (2) In contrast, IFN-alpha had a downregulatory effect on IL-10 levels in Candida -stimulated PBMC,with particularly strong suppressive effect in HIV-infected patients. (3) Furthermore, IFN-alpha had a significant but modest stimulatory effect on IL-2 levels in PHA- and Candida -stimulated PBMC and anti-CD3-stimulated T cells. (4) IFN-alpha enhanced IL-12 levels in a dose-dependent manner in LPS-stimulated PBMC in both patients and controls. Our findings that IFN-alpha markedly enhanced IL-10 and modestly enhanced IL-2 and IL-12, suggest a net immunosuppressive effect of IFN-alpha in HIV-infected patients, possibly contributing to progression of immunodeficiency in these patients.

Adult↗

Effect of pravastatin on plasma markers of inflammation and peripheral endothelial function in male heart transplant recipients.

Statins appear to have several biologic effects beyond those of lipid metabolism, and we hypothesized that immunomodulating effects of statins are important for the beneficial effects of these medications after heart transplantation. Our findings suggest that pravastatin treatment reduces plasma markers of inflammation and improves peripheral endothelial function in heart transplant recipients, possibly contributing to the observed clinical benefits of statin treatment in these patients.

Cell Adhesion Molecules↗

Immunomodulating therapy with intravenous immunoglobulin in patients with chronic heart failure.

BACKGROUND: Congestive heart failure (CHF) is characterized by enhanced immune activation, and immune-mediated mechanisms may play a pathogenic role in this disorder. Based on the immunomodulatory effects of intravenous immunoglobulin (IVIG), we hypothesized that IVIG could downregulate inflammatory responses in CHF patients and have potential beneficial effects on the left ventricular ejection fraction (LVEF). METHODS AND RESULTS: Forty patients with chronic symptomatic CHF and LVEF of <40%, stratified according to cause (ie, ischemic and idiopathic dilated cardiomyopathy), were randomized in a double-blind fashion to receive therapy with IVIG or placebo for a total period of 26 weeks. Our main findings were that (1) IVIG, but not placebo, induced a marked rise in plasma levels of the anti-inflammatory mediators interleukin (IL)-10, IL-1 receptor antagonist, and soluble tumor necrosis factor receptors; (2) significantly correlated with these anti-inflammatory effects, IVIG, but not placebo, induced a significant increase in LVEF from 26+/-2% to 31+/-3% (P:<0.01), and this was found independent of the cause of heart failure; and (3) N-terminal pro-atrial natriuretic peptide decreased significantly after induction therapy and continued to decrease toward the end of study during IVIG therapy (P:<0.001) but remained unchanged during placebo. CONCLUSIONS: We demonstrated an IVIG-induced change in the balance between inflammatory and anti-inflammatory cytokines that favored an anti-inflammatory net effect in CHF. This effect was significantly correlated with an improvement in LVEF, suggesting a potential for immunomodulating therapy in addition to optimal conventional cardiovascular treatment regimens in CHF patients.

Adjuvants, Immunologic↗

Monocyte chemoattractant protein-1 enhances and interleukin-10 suppresses the production of inflammatory cytokines in adult rat cardiomyocytes.

OBJECTIVE: Chemokines control the migration of leukocytes to inflamed tissue, and in particular monocyte chemoattractant protein (MCP)-1 has been implicated in the pathogenesis of several cardiovascular disorders such as chronic heart failure (CHF) and myocarditis. We hypothesised that MCP-1 may directly contribute to an inflammatory response in the cardiomyocytes, and in the present study we examined in adult rat cardiomyocytes: (i) the effect of tumour necrosis factor (TNF)alpha on MCP-1 production, (ii) the effect of MCP-1 on production of other inflammatory cytokines, and (iii) if the anti-inflammatory cytokine interleukin (IL)-10 could suppress any TNFalpha-induced MCP- 1 production. METHODS: We used enzyme immunoassays, RNase protection assays and slot blot analysis to measure protein and mRNA levels of various cytokines in adult rat cardiomyocyte cultures. RESULTS: (i) We found a approximately 6.4-fold increase of the MCP-1 level accompanied by an increase in MCP-1 mRNA accumulation in cardiomyocyte cultures after TNFalpha stimulation. (ii) In contrast, TNFalpha had no effect on IL-10 and only a modest effect on IL-1beta and IL-6 levels in these cells. (iii) Importantly, MCP-1 stimulated inflammatory response in cardiomyocytes by enhancing IL- 1beta and IL-6 levels in these cells as found at both the protein and mRNA level. (iv) Co-stim-ulation with IL-10 resulted in a approximately 55% reduction in TNFalpha-stimulated MCP-1 levels in cardiomyocyte culture supernatants. CONCLUSION: The present study demonstrates for the first time that MCP- 1 can directly affect cardiomyocytes, and we introduce MCP-1 as a potential enhancer and IL- 10 as a potential suppresser of inflammatory responses within the myocardium.

Animals↗

Effect of folic acid treatment on endothelium-dependent vasodilation and nitric oxide-derived end products in hyperhomocysteinemic subjects.

PURPOSE: An elevated plasma homocysteine concentration is an independent risk factor for cardiovascular diseases. In this study, we tested the hypothesis that hyperhomocysteinemia induces endothelial dysfunction mediated, at least in part, through nitric oxide-dependent mechanisms and that folic acid supplementation improves endothelial function in hyperhomocysteinemic subjects. SUBJECTS AND METHODS: Endothelial function was evaluated in healthy controls and hyperhomocysteinemic subjects by measuring plasma levels of the nitric oxide-derived end products nitrite and nitrate and by assessing vasodilatory responses in the skin microcirculation and forearm vasculature. In the subjects with hyperhomocysteinemia, these measurements were repeated after 6 weeks and 12 months of folic acid supplementation. RESULTS: Compared with healthy controls, hyperhomocysteinemic subjects had significantly lower median plasma levels of nitric oxide-derived end products (12.1 microM [range 4.4 to 41.8] versus 24.6 microM [13.6 to 53.2]; P <0.001), a significantly lower endothelium-dependent vasodilatory response to acetylcholine (P <0.01), hyperemic response in the microcirculation (P <0.01), and total forearm blood flow during reactive hyperemia (P = 0.01). There was no significant difference in the endothelium-independent response. Folic acid treatment for 12 months increased the plasma level of nitric oxide-derived end products by 121% (95% confidence interval [CI], 72% to 170%), the vasodilatory response to acetylcholine by 124% (95% CI, 36% to 212%), and the ischemia-mediated hyperemic responses in the microcirculation by 60% (95% CI, 25% to 96%) and in the forearm vasculature by 47% (95% CI, 21% to 73%). CONCLUSIONS: Homocysteine appears to induce its atherogenic effect, at least in part, by depressing endothelial function, possibly through nitric oxide-dependent mechanisms. This effect can be reversed by folic acid supplementation.

Adult↗

Sustained retention of tetradecylthioacetic acid after local delivery reduces angioplasty-induced coronary stenosis in the minipig.

OBJECTIVE: The sulfur containing tetradecylthioacetic acid (TTA) has a profound effect on lipid metabolism and may also exert antioxidant and anti-inflammatory actions and thereby counteract coronary stenosis after angioplasty balloon injury. This study examined the possible modulatory effects of TTA, delivered locally, on coronary stenosis in minipigs and the underlying mechanisms of action. METHODS: Coronary balloon angioplasty injury using an oversized balloon was performed to 40 coronary arteries (20 minipigs, Sus Scrofa, Gammelsroed) followed by delivery of placebo or TTA via a local drug delivery balloon catheter. TTA was radiolabelled in four pigs. Quantitative coronary angiography and intracoronary ultrasound (ICUS) were performed before and after injury, and after 4 weeks of follow-up. The arteries were examined with histomorphometry. The antioxidant and anti-inflammatory effects of TTA were examined on LDL oxidation and stimulated release of interleukin (IL)-2 and IL-10 in human peripheral blood mononuclear cells (PBMC), respectively. RESULTS: Radioactive TTA was present in the coronary wall after 4 weeks. Angiographic minimal luminal diameter (mean+/-S.E.M.) in the placebo and TTA group was 1.3+/-0.1 vs. 2.2+/-0.2 mm (P<0.01) at follow-up, stenosis rate was 55 and 20% (P<0.01). Remodeling was -0.56+/-0.12 in the TTA group and -1.28+/-0.09 in the placebo group (P<0.01). TTA significantly prolonged the lag time of LDL oxidation. In phytohemagglutinin stimulated PBMC, TTA significantly decreased IL-2 levels and increased IL-10 levels suggesting a marked anti-inflammatory net effect. CONCLUSIONS: Local delivery of TTA reduces coronary artery stenosis after PTCA as assessed by both angiographic, histomorphometric and ICUS examinations by influencing vessel remodeling rather than intimal hyperplasia. The underlying mechanism(s) seem to involve antioxidant and anti-inflammatory effects of this fatty acid analogue.

Administration, Topical↗

Interaction between chemokines and oxidative stress: possible pathogenic role in acute coronary syndromes.

OBJECTIVES: We sought to study the relationships between chemokines and oxidative stress in acute coronary syndrome. BACKGROUND: In view of existing knowledge on the participation of leukocytes and oxidative stress in the pathogenesis of acute coronary syndrome, we hypothesized that chemokines may play a role in recruiting and activating leukocytes in this disorder. METHODS: The levels of chemokines and oxidative stress were studied in 38 patients with stable and 38 with unstable angina and in 20 controls. In separate in vitro experiments the effect of chemokines on reactive oxygen species in monocytes and the effect of antioxidants on chemokine levels in these cells were also studied. RESULTS: 1) Angina patients had raised serum levels of chemokines in both cross-sectional and longitudinal testing, with particularly high levels of interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1 and macrophage inflammatory peptide (MIP)-1-alpha in unstable disease. 2) T cells, and particularly monocytes, seem to contribute to the raised IL-8, MCP-1 and MIP-1-alpha levels in unstable angina. 3) Concomitantly, and significantly correlated with MCP-1 and IL-8 levels, stable and particularly unstable angina patients had decreased plasma levels of antioxidants and increased lipid peroxidation, suggesting enhanced oxidative stress. 4) Monocyte chemoattractant protein-1 enhanced the generation of O2- in monocytes from unstable angina patients, and the antioxidant glutathione-monoethyl ester suppressed the production of IL-8 and MCP-1 in these cells. CONCLUSIONS: Our findings suggest an interaction between chemokines and oxidative stress in unstable angina. This interaction may represent a vicious circle involved in the pathogenesis of acute coronary syndromes.

Adult↗