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Toll-like receptors (TLRs) are a family of pattern recognition receptors that serve as a key part of the innate immune system. TLRs play a role in coordinating the organism's first line of defence against invading microbes or tissue injury. TLR-mediated inflammation is an important pathogenic link between innate immunity and a diverse panel of clinical disorders. Among these processes are cardiovascular disorders such as atherosclerosis, heart failure, viral myocarditis or diabetic angiopathies. In the new area of TLRs, this has generated a lot of interest from pharmaceutical companies as well as the investment communities. The improved understanding of TLRs, their key ligands and signaling cascades brought a number of diagnostic methods and compounds into clinical development. The first potential applications for TLR compounds include therapies for cardiovascular disease. The idea of this article is to describe the molecular basis of TLR signaling and review corresponding new inventions relating to TLR system and drug targets in cardiovascular disease.

Chronic heart failure is a complex catabolic state that carries a devastating prognosis. The transition from stable disease to cardiac cachexia is not well understood. Mechanisms that maintain the wasting process involve neurohormones and pro-inflammatory cytokines, which contribute to an imbalance in anabolic and catabolic pathways. A decrease in food intake alone rarely triggers the development of a wasting process, but dietary deficiencies in micronutrients and macronutrients contribute to the progression of the disease. Malabsorption from the gut as a result of bowel wall edema and decreased bowel perfusion also plays an important role. This article describes the complex interplay of hormonal systems in energy balance in patients with chronic heart failure as well as other factors such as malabsorption and dietary deficiencies that contribute to the wasting process. Finally, therapeutic approaches are discussed. These include dietary advice, ongoing studies, and future possibilities.

Cardiac biomarkers play an important role in and provide better pathophysiological understanding of chronic heart failure (CHF). Natriuretic peptides, especially B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP), were found to be useful in the diagnostic assessment and prognostic stratification of patients with CHF. However, they fail to fulfill all the criteria of an ideal biomarker. Currently, we still do not have a single biomarker or a combination of biomarkers to answer all the clinically relevant questions in CHF. Consequently, some widely available biomarkers might have been overlooked in the field of heart failure. This review discusses several biomarkers, and speculates on the possible roles of combining two or more of them. In this respect, hemoglobin, cholesterol, uric acid, and recently identified proteins may prove to be relevant to the field of CHF. Lastly, we anticipate the potential of biomarkers in a variety of chronic diseases with similar pathophysiology.

Toll-like receptors (TLRs) form a family of pattern recognition receptors that have emerged as key mediators of innate immunity. These receptors sense invading microbes and initiate the immune response. TLR-mediated inflammation is an important pathogenic link between innate immunity and a diverse panel of clinical disorders. Among the processes in which TLRs play a role are cardiovascular disorders such as cardiac ischaemia, coronary artery disease, ventricular remodelling, cancer angiogenesis or transplant rejection. From these, many important opportunities for disease modification through TLR signalling manipulation can be imagined. Their role as potential targets for therapeutic intervention is just beginning to be appreciated and this article reviews the current status of these treatment strategies for cardiovascular disease.

Background: Activation of the endotoxin (LPS) receptor, CD14, leads to tumor necrosis factor-alpha (TNF) production. Plasma LPS activity is elevated in patients with severe chronic heart failure (CHF). An anti-CD14 antibody, IC14, blocks TNF production in healthy volunteers. It is not known whether IC14 prevents TNF production in CHF patients., Methods and Results: Blood from 20 CHF patients (age 64+/-2.1 years, NYHA class 2.2+/-0.1, LVEF 27+/-3%, mean+/-SEM) was pre-incubated with 0.5, 1.0, 5.0, 10 and 50 microg/mL IC14 for 1 h followed by incubation with 1 or 10 ng/mL LPS for 6 h. Fourteen subjects served as controls (58+/-2.4 years). LPS-stimulated TNF release was 76% and 60% greater at 1 and 10 ng/mL LPS, respectively, in CHF patients versus controls (p=0.07 and p=0.008). IC14 at concentrations of 5.0, 10 and 50 microg/mL substantially reduced TNF production in response to stimulation with LPS (all p<0.05). CD14 receptor density was similar in patients and controls. In controls, but not in CHF patients, there was a positive correlation between CD14 receptor density and TNF production (r=0.61, p=0.03)., Conclusion: IC14 suppresses LPS-stimulated whole blood TNF production in patients with CHF and in normal subjects and therefore may represent a novel therapeutic strategy for CHF patients with systemic immune activation.

Chronic heart failure (CHF) represents a major public health burden in developed countries. The introduction of new treatments has helped to improve its prognosis in recent years. However, it is still not possible to directly target the immunological aspects of the disease. In fact, chronic immune activation with the up-regulation of pro-inflammatory substances in the plasma remains an important feature of the disease, independently of its aetiology. Autoimmune mechanisms play a significant role in a subgroup of patients with dilated cardiomyopathy. The interplay between the two systems has not been established so far. This review briefly summarizes immune and autoimmune mechanisms in CHF.

Aims: Chronic heart failure (CHF) is a common and leading cause of death in industrialized countries. The potential benefits of micronutrient supplementation in CHF are extensive. Therefore, we examined the influence of long-term multiple micronutrient supplementation on left ventricular (LV) function, levels of pro-inflammatory cytokines, and quality-of-life (QoL) in elderly patients with CHF., Methods and Results: Thirty CHF patients [age 75.4 (0.7), mean (SEM), LV ejection fraction (LVEF) < or =35%] were randomized to receive capsules containing a combination of high-dose micronutrients (calcium, magnesium, zinc, copper, selenium, vitamin A, thiamine, riboflavin, vitamin B(6), folate, vitamin B(12), vitamin C, vitamin E, vitamin D, and Coenzyme Q10) or placebo for 9 months in a double-blind fashion. All subjects were on stable optimal medical therapy for at least 3 months before enrolment. At randomization and at study end, tumour necrosis factor-alpha and its soluble receptors TNFR-1 and TNFR-2 were measured and six-minute walk test and QoL were assessed. Cardiac magnetic resonance scanning was performed to evaluate cardiac dimensions and LVEF. Two patients died during follow-up. The remaining patients (14 randomized to placebo and 14 to micronutrients) were well matched for LV function, symptoms, and exercise capacity. At the end of the follow-up period, LV volumes were reduced in the intervention group with no change in the placebo group [-13.1 (17.1)% vs. +3.8 (10.0)%; P<0.05]. LVEF increased by 5.3+/-1.4% in the intervention group and was unchanged in the placebo group (P<0.05). Patients taking micronutrients also had a significant improvement in QoL score between enrolment and study end [+9.5 (1.6)%; P<0.05], whereas those taking placebo had a slight deterioration [-1.1 (0.8)%; P=0.12]. Six-minute walk test and inflammatory cytokine levels remained unchanged in both groups., Conclusion: Long-term multiple micronutrient supplementation can improve LV volumes and LVEF and QoL scores in elderly patients with heart failure due to LV systolic dysfunction.

Aim: To evaluate the activation of transcriptional nuclear factor kappa-B (NF-kappaB) in peripheral blood leukocytes (PBL) from patients with chronic heart failure (CHF). In vitro experiments were used to elucidate the role of lipopolysaccharide (LPS) as a stimulus for the NF-kappaB system in PBL., Methods and Results: We examined 46 CHF patients (age: 62+/-1 years, LVEF: 31+/-1%, NYHA class: 2.7+/-0.1), 11 coronary artery disease (CAD) patients without CHF, and 13 healthy young subjects. The immunocytochemical localisation of NF-kappaB in PBL was assessed using a polyclonal rabbit IgG anti-c-Rel-subunit antibody. NF-kappaB activation was expressed as the percentage of PBL nuclei stained positively for c-Rel (NF-kappaB+cell). PBL from healthy controls were exposed in vitro to the following concentrations of LPS from Escherichia coli (strain O111:B4): 0.1, 10 and 5000 ng/mL. CHF patients demonstrated the highest NF-kappaB activation in PBL (NF-kappaB+cells [%]: 37.1+/-1.5) as compared to CAD patients (29.1+/-3.0%) and controls (12.6+/-1.5%) (all p<0.05). There were three main clinical determinants of NF-kappaB activation in PBL from CHF patients: peak oxygen consumption (r=0.53, p=0.025), presence of peripheral oedema (r=0.37, p<0.05) and serum C-reactive protein (r=0.40, p=0.02). In PBL from healthy subjects, LPS at all concentrations increased NF-kappaB activity towards the pattern detected in CHF., Conclusions: The NF-kappaB system is highly overactive in PBL from CHF patients. LPS at low concentrations in peripheral blood may be involved in NF-kappaB activation in PBL, and is a potential target for future therapeutic applications.

Objectives: The aim of this study was to determine the significance of insulin resistance as an independent risk factor for impaired prognosis in patients with chronic heart failure (CHF)., Background: In CHF, impaired insulin sensitivity (S(I)) indicates abnormal energy metabolism and is related to decreased exercise capacity and muscle fatigue. The relationship between insulin resistance (i.e., low S(I)) and survival in patients with CHF has not been established., Methods: We prospectively studied 105 male patients with CHF due to ischemic (63%) or non-ischemic (37%) etiology. All patients were in clinically stable condition (age 62 +/- 1 year, New York Heart Association [NYHA] functional class 2.6 +/- 0.1, left ventricular ejection fraction [LVEF] 28 +/- 2%, peak oxygen uptake [Vo(2)] 18.2 +/- 0.7 ml/kg/min). Insulin sensitivity was assessed from glucose and insulin dynamic profiles during an intravenous glucose tolerance test using the minimal model technique., Results: During a mean follow-up period of 44 +/- 4 months, 53 patients (50%) died. Patients with S(I) below the median value (median: 1.82 min(-1) x microU x ml(-1).10(4); n = 52) had worse survival (at two years 61% [range 47% to 74%]) than patients with S(I) above the median value (n = 53; at two years 83% [range 73% to 93%]; risk ratio [RR] 0.38, 95% confidence interval [CI] 0.21 to 0.67; p = 0.001). Both patient groups were similar in terms of age, NYHA functional class, and body composition parameters (dual-energy X-ray absorptiometric scan; p > 0.2), but patients with a lower S(I) had a lower LVEF (24 +/- 2% vs. 33 +/- 3%) and peak Vo(2) (16.8 +/- 1.0 ml/kg/min vs. 19.7 +/- 1.0 ml/kg/min; both p < 0.05). On univariate Cox analysis, higher S(I) predicted better survival (RR 0.56, 95% CI 0.35 to 0.89; p = 0.015). On stepwise multivariate analysis, S(I) predicted mortality independently of other variables., Conclusions: In patients with CHF, lower S(I) relates to higher mortality, independent of body composition and established prognosticators. Impaired S(I) may have implications in the pathophysiology of CHF disease progression. Therapeutically targeting impaired insulin sensitivity may potentially be beneficial in patients with CHF.

Background: Increased levels of bacterial lipopolysaccharide (LPS) have been demonstrated in chronic heart failure (CHF). LPS can induce cellular desensitization, with specific down-regulation of LPS-mediated cellular tumor necrosis factor (TNF-alpha) production which does not affect other cytokine parameters. It is not known if LPS desensitization occurs in CHF., Methods and Results: Mononuclear cells from 24 CHF patients (mean age 70+/-2 years, age range 58 to 78 years, NYHA class 3.0+/-0.2) and 11 healthy controls (mean age 53+/-3 years, age range 39 to 75 years) were separated from venous blood and cultured for 24 h with LPS (E. coli, 0-10 ng/mL). Culture supernatants were tested for TNF-alpha and interleukin-1 receptor antagonist (IL-1RA). Patients were subgrouped into mild (n=10), moderate (n=5), and severe (n=9) CHF. Independently of age, mononuclear cells from patients with severe heart failure produced less TNF-alpha than controls (p<0.05) and patients with mild (p<0.001) or moderate CHF (p<0.05). IL-1RA release was higher for CHF patients as a group, compared with controls (p<0.05). There was no significant difference in IL-1RA release between CHF patient subgroups., Conclusions: Mononuclear cells from patients with severe heart failure produce significantly less TNF-alpha than healthy controls or patients with mild to moderate disease. Production of IL-1RA is not affected. This resembles a picture indicative of LPS desensitization occurring in patients with severe CHF.

Background: Endotoxin [lipopolysaccharide (LPS)] may be an important stimulus for cytokine release in patients with chronic heart failure (CHF). We sought to investigate the relationship between whole blood endotoxin responsiveness and serum lipoprotein concentrations. It is not known if low-dose LPS is sufficient to stimulate immune activation., Methods and Results: Whole blood from 32 CHF patients (mean age 66+/-2 years, NYHA class 2.7+/-0.2, five female) and 11 healthy control subjects (mean age 47+/-4 years, six female) was stimulated with LPS at nine different concentrations (0.001 to 10 ng/mL), and tumor necrosis factor (TNF-alpha) release was quantified. Reference standard endotoxin at concentrations of 0, 0.6, 1, and 3 EU/ml was added to whole blood from nine CHF patients (age 64+/-9.1 years, all NYHA class II, eight male) and incubated for 6 h, the TNF-alpha production being measured. Serum lipoproteins were quantified using standard techniques. In CHF patients, there was an inverse relationship between whole blood TNF-alpha release and serum cholesterol which was strongest at 0.6 ng/mL of LPS (r=-0.53, p=0.002). A similar although weaker relationship was found for serum HDL. No such correlation was found in healthy subjects or with serum LDL (all r(2)<0.1). Low concentrations of LPS induced a stepwise increase in TNF-alpha release from whole blood to concentrations well above those seen in CHF., Conclusions: Serum lipoproteins may play an important role in regulating LPS bioactivity in CHF. Very low LPS activity, at levels seen in vivo in CHF, can induce significant TNF-alpha production ex vivo.

Increased levels of tumor necrosis factor-alpha (TNF-alpha) correlate with poor prognoses in chronic heart failure (CHF). This study demonstrated that noradrenaline and isoproterenol inhibit TNF-alpha production in patients with CHF in ex vivo whole blood in a dose-dependent fashion. The beta-blocker bisoprolol abolishes this effect.

Several lines of evidence suggest that chronic heart failure is a state of chronic inflammation. Indeed, various pro-inflammatory markers, including the cytokines TNF-alpha, and interleukin 6 and 1, are activated in the course of the disease. In chronic heart failure, these substances are frequently induced even before the classical neurohormones angiotensin II and noradrenaline. Although the recently published anti-TNF-alpha trials with etanercept and infliximab have called the beneficial effects of targeting single cytokines into question, the overactive immune system remains a promising target for therapeutic interventions, which aim at slowing down disease progression. Broader approaches are required. These comprise targeting bacterial lipopolysaccharide (endotoxin) that enters the circulation through the oedematous gut wall, immune modulation therapy with patient-derived whole blood exposed to oxidative stress, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (the so-called statins) and a number of other substances including pentoxifylline and thalidomide.

Background: Heat shock protein 70 (Hsp70) is essential for cellular recovery, survival and maintenance of cellular function. Research into the possible use of Hsp70 as a cytoprotective therapeutic agent is ongoing. Chronic heart failure (CHF) is a state associated with systemic inflammation, particularly in patients with cardiac cachexia. We hypothesised that circulating Hsp70 levels are elevated in patients with CHF, more so in cachechtic patients, and that Hsp70 levels would relate to mortality., Methods and Results: We studied 107 patients (28 female, age 67+/-1 years, NYHA class 2.6+/-0.6 and LVEF 29+/-1%, mean+/-SEM) and 21 controls. Cardiac cachexia was present in 32 patients. Hsp70 was detectable in 41% of CHF patients and in only 10% of controls. Overall serum levels were significantly higher in CHF patients vs. controls (7.13+/-1.34 vs. 0.38+/-0.26 ng/ml, p=0.004). Hsp70 levels were also higher in patients with advanced CHF according to NYHA class or the presence of cachexia (all p<0.05). There was no relation between Hsp70 and left ventricular ejection fraction, maximal oxygen consumption and several inflammatory cytokines (all p>0.05). During a median follow-up of 208 days (range 4-2745 days) 38 patients died. Cox proportional hazards analysis showed that increased Hsp70 did not predict survival (p=0.17)., Conclusion: Hsp70 levels are elevated in CHF patients, particularly in those with cardiac cachexia and Hsp70 relates to disease severity but not to survival. The significance of the relationship of Hsp70 expression and morbidity in CHF needs further evaluation.

Immune activation plays a significant role in the development and progression of chronic heart failure (CHF). Indeed, pro-inflammatory cytokines, especially tumour necrosis factor-alpha (TNFalpha) are activated in this condition and exert direct detrimental actions on the myocardium. Physiological dampeners of TNFalpha production, such as interleukin-10, catecholamines, cortisol, and others fail in the course of the disease. However, the outcomes of two large-scale clinical trials with etanercept and infliximab, which directly antagonise TNFalpha have been rather disappointing. Nevertheless, TNFalpha antagonism remains a major target of CHF therapy, although counterbalancing this cytokine alone may not be sufficient.

Statins, also known as 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, consistently reduce cardiovascular risk. It has recently emerged that cholesterol reduction is not their only mode of action, with current research largely focused on the pleiotropic effects of statins. These include the improvement of endothelial dysfunction, their anti-inflammatory properties, and the mobilization of bone marrow-derived endothelial progenitor cells. All these effects are potentially beneficial in chronic heart failure (CHF), although prospective trials are needed to confirm this. However, cholesterol reduction by statins per se may prove detrimental in patients with CHF, as cholesterol seems to be able to inactivate endotoxin as a stimulus for proinflammatory cytokine production. It is therefore tempting to speculate that low doses of statins still confer pleiotropic effects without lowering plasma cholesterol levels.

Inflammatory cytokines are thought to contribute to the development and progression of chronic heart failure (CHF). It has been shown that especially tumor necrosis factor-alpha (TNF) is activated in patients with CHF and exerts detrimental effects on the myocardium. Recent studies have demonstrated that circulating levels of TNF, soluble TNF receptors 1 and 2 and interleukin-6 are strong prognostic markers. The results of two randomized studies directly antagonizing TNF in CHF patients were rather disappointing. Nevertheless, TNF antagonism remains a therapeutic option and should be focussed on patients with systemic immune activation, particularly at times of exacerbation.

Background: Ageing is associated with an altered immune response. Elevated plasma levels of tumour necrosis factor-alpha (TNF-alpha) are present in patients with advanced chronic heart failure (CHF). However, the relationship between age and the immune response in CHF is unknown., Methods: We investigated the relationship between age and the TNF-alpha generating capacity of lipopolysaccharide (LPS) stimulated peripheral blood mononuclear cells (PBMC) in nine healthy control subjects (mean age 51.6+/-3.6 years, age range 39-75 years) and 22 stable patients with CHF (mean age 68.3+/-1.5 years, age range 52-78 years, NYHA class 3.0+/-0.2). We also tested the TNF-alpha generating capacity of all control subjects and 18 CHF patients in whole blood cultures., Results: Subjects were subgrouped according to baseline TNF-alpha secretion in PBMC cultures into low- and high-responders, with the latter producing TNF-alpha even without LPS stimulation. High-responders produced more TNF-alpha than low-responders at all LPS doses (0.001-10 ng/ml, P<0.0001, repeated measures ANOVA), and high-responders were significantly older than low-responders (controls: 65.8+/-9.2 vs. 47.5+/-2.5 years; patients: 71.9+/-1.9 vs. 65.9+/-1.9 years, both P<0.05). Age correlated with TNF-alpha production in both patients and controls. This effect was independent of NYHA class., Conclusions: LPS-responsiveness appears to relate to age in both healthy controls and CHF patients. When assessing the immune status of CHF patients, age should therefore be considered an important confounding factor. In whole blood these findings could only be confirmed at the highest LPS concentration used, thus suggesting that certain factors in the blood may be able to abolish LPS activity at lower concentrations.

Endothelial dysfunction plays an important role in a number of cardiovascular diseases. An important pathogenetic factor for the development of endothelial dysfunction is lack of nitric oxide (NO), which is a potent endothelium-derived vasodilating substance. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins), originally designed to lower plasma cholesterol levels, seem to ameliorate endothelial dysfunction by a mechanism so far only partly understood. However, statins increase nitric oxide synthase activity. It has been speculated that this and other "side effects" of statin treatment are due to inhibition of Rho, an intracellular signalling protein that initiates Rho kinase transcription. Moreover, statins possess anti-inflammatory characteristics. Some statins have proven to lower plasma levels of C-reactive protein, which is induced by pro-inflammatory cytokines. Other statins have been demonstrated to directly inhibit pro-inflammatory cytokine induction. Finally, some data suggest that statins might be able to counterbalance an increased production of oxygen free radicals. Since chronic heart failure is accompanied not only by endothelial dysfunction, but also by pro-inflammatory cytokine activation and enhanced formation of oxygen free radicals, it is tempting to speculate that statins might be an ideal candidate to treat certain features of this disease. The doses needed to achieve the desired effects might be much lower than those needed to treat hypercholesterolemia.

Bacterial endotoxin activity is elevated in patients with decompensated chronic heart failure (HF) and acts as a potent stimulus for immune activation. We sought to determine whether endotoxin, at an activity level seen in vivo (around 0.6 EU/ml), is sufficient to stimulate the secretion of tumor necrosis factor-alpha (TNF-alpha) and TNF-alpha soluble receptor (sTNFR2) in ex vivo whole blood from patients with HF. We studied 15 patients with HF (aged 65 +/- 1.9 years, New York Heart Association class 2.1 +/- 0.3, left ventricular ejection fraction 31 +/- 5%; mean +/- SEM), of whom 5 had cardiac cachexia, and 7 healthy control subjects (59 +/- 5 years, p = NS). Reference endotoxin was added to venous blood at concentrations of 0.6, 1.0, and 3.0 EU/ml, and was incubated for 6 hours. Endotoxin induced a dose-dependent increase in TNF-alpha release (p <0.05 in all groups). Patients with noncachectic HF produced significantly more TNF-alpha compared with controls after stimulation with 0.6, 1.0, and 3.0 EU/ml of endotoxin (113 +/- 46 vs 22 +/- 4 [p = 0.009], 149 +/- 48 vs 34 +/- 4 [p = 0.002], and 328 +/- 88 vs 89 +/- 16 pg/ml [p = 0.002], respectively; mean +/- SEM). Patients with cardiac cachexia produced significantly less TNF-alpha compared with patients without cardiac cachexia for all given concentrations (all p <0.05, analysis of variance p = 0.02). Production of sTNFR2 was greater at all concentrations of endotoxin versus controls (all p <0.05, analysis of variance p = 0.002). Plasma endotoxin levels were higher in patients with cardiac cachexia (4.3 times higher than in control subjects, p <0.005). Thus, low endotoxin activity, at levels seen in vivo in patients with HF, induces significant TNF-alpha and sTNFR2 production ex vivo. These results suggest that elevated plasma endotoxin activity observed in patients with HF is of pathophysiologic relevance.

Cachexia is seen in a number of chronic diseases, and it is always associated with a poor prognosis. Irrespective of etiology, the development of cachexia appears to share a common pathophysiological pathway. This includes induction of proteasome-dependent myofibril-degradation, which is thought to be secondary to stimulation by enhanced levels of pro-inflammatory cytokines. Elevation of tumor necrosis factor-alpha (TNFalpha) and other plasma cytokines has been demonstrated in many conditions associated with cachexia. Despite improved pathophysiological understanding, a specific treatment for cachexia has not yet been established. Whilst direct TNFalpha antagonism has therapeutic appeal, this review will focus on manipulation of downstream pathways and the potential benefits. For example, nuclear factor-kappaB (NF-kappaB) is one of the most important signal transducers of TNFalpha, and drugs targeting this signalling cascade might be useful in the treatment of cachexia. Although the use of some of these substances, for example glucocorticoids, remains controversial, others may prove beneficial in the treatment of this syndrome. The role of other approaches such as proteasome-inhibitors remains to be elucidated. Alternatively, interleukin-10 and other immunosuppressive cytokines may also be able to counterbalance certain features of cachexia.

Chronic heart failure (HF) is a state of inflammatory immune activation characterized by elevated circulating levels of tumor necrosis factor-alpha (TNF-alpha). Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine that inhibits TNF-alpha production and lessens endotoxin bioactivity. It is not known whether IL-10 reduces lipopolysaccharide (LPS) stimulated TNF-alpha production of peripheral blood mononuclear cells (PBMCs) from patients with chronic HF. PBMCs were isolated from 15 patients with chronic HF (New York Heart Association functional class 3.0 +/- 0.2, left ventricular ejection fraction 30 +/- 2%, peak oxygen consumption 18.1 +/- 0.8 ml/kg/min) and 15 healthy control subjects and stimulated with 1 and 10 ng/ml LPS for 24 hours with or without prior addition of IL-10 (10 ng/ml). TNF-alpha was quantified in cell-free supernatants by an enzyme-linked immunosorbent assay. TNF-alpha, soluble TNF receptors, IL-10, and LPS were quantified in plasma. LPS stimulated TNF-alpha production was highest in those patients in New York Heart Association class II (p <0.01 vs New York Heart Association class III and IV, p <0.001 vs control subjects). IL-10 reduced PBMC TNF-alpha production in all stimulated samples at 1 and 10 ng/ml LPS (mean reduction 43% at 1 ng/ml, p <0.01 and 55% at 10 ng/ml, p <0.0001). The percentage reduction in TNF-alpha release did not differ significantly between patients and control subjects or with respect to severity of chronic HF or baseline immune parameters. Independently of clinical severity, IL-10 profoundly inhibits TNF-alpha release from PBMCs isolated from patients with chronic HF. IL-10 is, therefore, a potential therapy for use in chronic HF associated with inflammatory immune activation.