The role of cytokines in the failing human heart

The Role of Pro-Inflammatory Cytokines in the Pathogenesis of Cardiovascular Disease

With cardiovascular disease (CVD) being a primary source of global morbidity and mortality, it is crucial that we understand the molecular pathophysiological mechanisms at play. Recently, numerous pro-inflammatory cytokines have been linked to several different CVDs, which are now often considered an adversely pro-inflammatory state. These cytokines most notably include interleukin-6 (IL-6),tumor necrosis factor (TNF)α, and the interleukin-1 (IL-1) family, amongst others. Not only does inflammation have intricate and complex interactions with pathophysiological processes such as oxidative stress and calcium mishandling, but it also plays a role in the balance between tissue repair and destruction. In this regard, pre-clinical and clinical evidence has clearly demonstrated the involvement and dynamic nature of pro-inflammatory cytokines in many heart conditions; however, the clinical utility of the findings so far remains unclear. Whether these cytokines can serve as markers or risk predictors of disease states or act as potential therapeutic targets, further extensive research is needed to fully understand the complex network of interactions that these molecules encompass in the context of heart disease. This review will highlight the significant advances in our understanding of the contributions of pro-inflammatory cytokines in CVDs, including ischemic heart disease (atherosclerosis, thrombosis, acute myocardial infarction, and ischemia-reperfusion injury), cardiac remodeling (hypertension, cardiac hypertrophy, cardiac fibrosis, cardiac apoptosis, and heart failure), different cardiomyopathies as well as ventricular arrhythmias and atrial fibrillation. In addition, this article is focused on discussing the shortcomings in both pathological and therapeutic aspects of pro-inflammatory cytokines in CVD that still need to be addressed by future studies.

Transcutaneous vagus nerve stimulation ameliorates cardiac abnormalities in chronically stressed rats

Chronically stressed patients often have low vagal tone and increased levels of proinflammatory cytokines, which increase their risk for developing cardiac dysfunction. Transcutaneous vagus nerve stimulation (taVNS) is a way to activate the parasympathetic system, which has the ability to reduce inflammation and antagonize excessive sympathetic responses. However, the effectiveness of taVNS in treating cardiac dysfunction caused by chronic unpredictable stress (CUS) has not been studied. To investigate this, we first validated a rat model of CUS, in which the rats were exposed to random stressors daily for 8 weeks. Post CUS, the rats were treated with taVNS (1.0 ms, 6 V, 6 Hz, for 40 min × 2 weeks, alternatively) and their cardiac function and cholinergic flow were evaluated. Furthermore, serum cardiac troponin I (cTnI), cardiac caspase-3, inducible nitric oxide synthase (iNOS), and transforming growth factor (TGF)-β1 expression in rats were also assessed. The chronically stressed rats showed depressed behavior with increased levels of serum corticosterone and proinflammatory cytokines. Electrocardiogram (ECG) and heart rate variability (HRV) studies revealed elevated heart rate, diminished vagal tone, and altered sinus rhythm in CUS rats. Furthermore, the CUS rats demonstrated cardiac hypertrophy and fibrosis with increased caspase-3, iNOS, and TGF-β expression in their myocardium and increased levels of serum cTnI. Interestingly, alternate taVNS therapy for 2 weeks, post CUS, helped alleviate these cardiac abnormalities. These suggest that taVNS could be a useful adjunctive and non-pharmacological approach for managing CUS induced cardiac dysfunction.

Olive oil protects against progression of heart failure by inhibiting remodeling of heart subsequent to myocardial infarction in rats

We examined the beneficial effects of olive oil against heart failure post-myocardial infarction (PMI), induced by coronary artery ligation in rats. Animals were divided into sham and ligated groups and fed either regular chow, olive oil (10% wt/wt), or corn oil (10% wt/wt) and were followed up to 16 weeks. On the echocardiography at 3 days (PMI), in the ligated regular chow (LRC), ligated olive oil (LOO), and ligated corn oil (LCO) left ventricular ejection fraction (LVEF) decrease was 12.14%, 16.42%, and 17.53% from the baseline, respectively. However, only LOO group improved LVEF significantly at 16 weeks PMI and became comparable with all sham groups. Both scar formation and collagen deposition at 16 weeks PMI were less pronounced in the LOO group. Myocardial TNF-α level at 4 weeks of PMI increased by 176%, 11%, and 181% in the LRC, LOO, and LCO groups, respectively. Plasma TNF-α levels in LOO were significantly lower than LRC group after 4 weeks of PMI. Myocardial redox ratio (reduced glutathione/oxidized glutathione) decreased at 4 weeks PMI by 44.4%, 16.4%, and 36.9% in the LRC, LOO, and LCO groups, respectively, compared to the baseline. These changes in the redox ratio at 16 weeks PMI were further exacerbated in the LRC and LCO groups. Lipid hydroperoxides formation increased at 4 weeks PMI by 137.4%, 14.6%, and 97.1% in the LRC, LOO, and LCO groups, respectively. Since coronary artery ligation decreased left ventricular ejection fraction, increased myocardial TNF-α and oxidative stress, and since olive oil was able to inhibit these effects, it is proposed that dietary olive oil modulates cardiac remodeling and heart failure subsequent to myocardial infarction.

Changes of Laboratory Cardiac Markers and Mechanisms of Cardiac Injury in Coronavirus Disease 2019

Some patients with coronavirus disease 2019 (COVID-19) show abnormal changes in laboratory myocardial injury markers, suggesting that patients with myocardial injury have a higher mortality rate than those without myocardial injury. This article reviews the possible mechanism of myocardial injury in patients with COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects the patients with COVID-19 in aspects of direct infection of myocardial injury, specific binding to functional receptors on cardiomyocytes, and immune-mediated myocardial injury. During hospitalization, the monitoring of laboratory myocardial injury markers in patients of COVID-19 should be strengthened.

Post-TTM Rebound Pyrexia after Ischemia-Reperfusion Injury Results in Sterile Inflammation and Apoptosis in Cardiomyocytes

Introduction

Fever is frequently observed after acute ischemic events and is associated with poor outcome and higher mortality. Targeted temperature management (TTM) is recommended for neuroprotection in comatose cardiac arrest survivors, but pyrexia after rewarming is proven to be detrimental in clinical trials. However, the cellular mechanisms and kinetics of post-TTM rebound pyrexia remain to be elucidated. Therefore, we investigated the effects of cooling and post-TTM pyrexia on the inflammatory response and apoptosis in a cardiomyocyte ischemia-reperfusion (IR) injury model.

Methods

HL-1 cardiomyocytes were divided into the following groups to investigate the effect of oxygen-glucose deprivation/reperfusion (OGD/R), hypothermia (33.5°C), and pyrexia (40°C): normoxia controls maintained at 37°C and warmed to 40°C, OGD/R groups maintained at 37°C and cooled to 33.5°C for 24 h with rewarming to 37°C, and OGD/R pyrexia groups further warmed from 37 to 40°C. Caspase-3 and RBM3 were assessed by Western blot and TNF-α, IL-6, IL-1β, SOCS3, iNOS, and RBM3 transcriptions by RT-qPCR.

Results

OGD-induced oxidative stress (iNOS) in cardiomyocytes was attenuated post-TTM by cooling. Cytokine transcriptions were suppressed by OGD, while reperfusion induced significant TNF-α transcription that was exacerbated by cooling. Significant inductions of TNF-α, IL-6, IL-1β, and SOCS3 were observed in noncooled, but not in cooled and rewarmed, OGD/R-injured cardiomyocytes. Further warming to pyrexia induced a sterile inflammatory response in OGD/R-injured groups that was attenuated by previous cooling, but no inflammation was observed in pyrexic normoxia groups. Moreover, cytoprotective RBM3 expression was induced by cooling but suppressed by pyrexia, correlating with apoptotic caspase-3 activation.

Conclusion

Our findings show that maintaining a period of post-TTM “therapeutic normothermia” is effective in preventing secondary apoptosis-driven myocardial cell death, thus minimizing the infarct area and further release of mediators of the innate sterile inflammatory response after acute IR injury.

Propofol attenuates myocardial ischemia reperfusion injury partly through inhibition of resident cardiac mast cell activation

Cardiac mast cell activation is involved in the process of myocardial ischemia reperfusion (I/R) injury and exacerbates myocardial infarction. Propofol, an anesthetic with antioxidant property, can reduce myocardial infarct size in I/R injury. The present study was designed to investigate whether propofol can attenuate myocardial I/R injury by inhibiting resident cardiac mast cell activation by a Langendorff model. Thirty rats were randomly assigned to 5 groups (n=6 per group): control group and four test groups (I/R, I/R+compound 48/80, I/R+propofol, I/R+compound 48/80+propofol). Cultured RBL-2H3 cells were pretreated with propofol and subjected to mast cell degranulator compound48/80 (C48/80).Microscopically, degradation of myofibrillar and degranulation of mast cells were studied using hematoxylin-eosin toluidine blue staining techniques. After the effluent was assayed for tryptase, LDH, CK-MB and cTnI, myocardial tissue was evaluated for cytokine levels and infarct area. Heart subjected to I/R showed significantly increased expression of cytokines (TNF-α and IL-6), LDH, CK-MB and cTnI. In addition, the I/R-induced heart also showed greater histopathological injury and a larger infarction zone, following increased mast cell degranulation with concomitant rise in tryptase. Mast cell degranulation by C48/80 further aggravated I/R injury. However, all of these effects were suppressed by propofol pretreatment, which also abrogated C48/80-mediated exacerbation of I/R injury. Also, propofol attenuated the C48/80-evoked tryptase and histamine release in RBL-2H3 cells. It is concluded that pretreatment of propofol confers protection against I/R injury partly by inhibiting resident cardiac mast cell activation.

Dexmedetomidine preconditioning for myocardial protection in ischaemia-reperfusion injury in rats by downregulation of the high mobility group box 1-toll-like receptor 4-nuclear factor κB signalling pathway

Pharmacological preconditioning reduces myocardial infarct size in ischaemia-reperfusion (I-R) injury. Dexmedetomidine, a selective α₂ -adrenoceptor agonist, has a proven cardioprotective effect when administered prior to I-R, although the underlying mechanisms for this effect are not fully understood. We evaluated whether dexmedetomidine preconditioning could induce a myocardio-protective effect against I-R injury by inhibiting associated inflammatory processes through downregulation of the high mobility group box 1 (HMGB1)-toll-like receptor 4 (TLR4)-nuclear factor κB (NF-κB) signalling pathway. Seventy rats were randomly assigned to seven groups: a control and six test groups, involving I-R for 30 and 120 minutes, respectively, in isolated rat hearts and different pretreatment protocols with dexmedetomidine (10 nmol/L) as well as yohimbine (1 μmol/L) and recombinant HMGB1 peptide (rHMGB1; 20 μg/L), alone or in combination with dexmedetomidine. Cardiac function was recorded; myocardial HMGB1, TLR4, and NF-κB activities and levels of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured as were lactate dehydrogenase (LDH) and creatine kinase (CK) in coronary outflow. Dexmedetomidine preconditioning significantly improved cardiac function (P<.05), downregulated the expression of HMGB1-TLR4-NF-κB, reduced levels of TNF-α and IL-6 in isolated ventricles during I-R injury, and significantly reduced CK and LDH levels in coronary outflow (P<.05). All of these effects were partially reversed by yohimbine (P<.05) or rHMGB1 (P<.05). Dexmedetomidine preconditioning alleviated myocardial I-R injury in rats through inhibition of inflammatory processes associated with downregulation of the HMGB1-TLR4-NF-κB signalling pathway via activation at α₂ -adrenergic receptors.

Toll-like receptors: new players in myocardial ischemia/reperfusion injury

Innate immune and inflammatory responses have been implicated in myocardial ischemia/reperfusion (I/R) injury. However, the mechanisms by which innate immunity and inflammatory response are involved in myocardial I/R have not been elucidated completely. Recent studies highlight the role of Toll-like receptors (TLRs) in the induction of innate immune and inflammatory responses. Growing evidence has demonstrated that TLRs play a critical role in myocardial I/R injury. Specifically, deficiency of TLR4 protects the myocardium from ischemic injury, whereas modulation of TLR2 induces cardioprotection against ischemic insult. Importantly, cardioprotection induced by modulation of TLRs involves activation of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, suggesting that there is a crosstalk between TLRs and PI3K/Akt signaling pathways. In addition, TLRs also associate with other coreceptors, such as macrophage scavenger receptors in the recognition of their ligands. TLRs are also involved in the induction of angiogenesis, modulation of stem cell function, and expression of microRNA, which are currently important topic areas in myocardial I/R. Understanding how TLRs contribute to myocardial I/R injury could provide basic scientific knowledge for the development of new therapeutic approaches for the treatment and management of patients with heart attack.

The Utility of Animal Models in Understanding Links between Psychosocial Processes and Cardiovascular Health

A bidirectional association between mood disorders and cardiovascular disease has been described; however, the neurobiological mechanisms that underlie this link have not been fully elucidated. The purpose of this review is first to describe some of the important behavioral neurobiological processes that are common to both mood and cardiovascular disorders. Second, this review focuses on the value of conducting research with animal models (primarily rodents) to investigate potential behavioral, physiological, and neural processes involved in the association of mood disorders and cardiovascular disease. In combination with findings from human research, the study of mechanisms underlying mood and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and can promote the development of novel interventions for individuals with these comorbid conditions.

Blood gene expression signatures associate with heart failure outcomes

Gene expression signatures in blood correlate with specific diseases. Such signatures may serve as valuable diagnostic and prognostic tools in disease management. Blood gene expression signatures associated with heart failure may be applied to predict prognosis, monitor disease progression, and optimize treatment. Blood gene expression profiles were generated for 71 subjects with heart failure and 15 controls without heart failure, using the Affymetrix GeneChip U133Plus2.0. Survival analysis identified 197 "mortality genes" that were significantly associated with patient outcome. Functional categorization showed that genes associated with T cell receptor signaling were most significantly overpresented. Cluster analysis of these T cell receptor signaling genes significantly categorized heart failure patients into three risk groups (P = 0.031) that were distinct from the three risk groups categorized by New York Heart Association (NYHA) Classification (P = 0.0002). By combining the analysis of clinical assessment (NYHA class) with T cell receptor signaling gene expression, we proposed a model that demonstrated an even greater differentiation of patients at risk (P = 0.0001). In this discovery study, we identified blood expression signatures associated with heart failure patient outcomes. Characterization of these mortality genes helped identify a set of T cell receptor signaling genes that may be of utility in predicting survival of heart failure patients. These data raise the possibility of prospectively risk stratifying patients with heart failure by integrating blood gene expression signatures with current clinical assessment.

Cellular cardiomyoplasty: what have we learned?

Restoring blood flow, improving perfusion, reducing clinical symptoms, and augmenting ventricular function are the goals after acute myocardial infarction. Other than cardiac transplantation, no standard clinical procedure is available to restore damaged myocardium. Since we first reported cellular cardiomyoplasty in 1989, successful outcomes have been confirmed by experimental and clinical studies, but definitive long-term efficacy requires large-scale placebo-controlled double-blind randomized trials. On meta-analysis, stem cell-treated groups had significantly improved left ventricular ejection fraction, reduced infarct scar size, and decreased left ventricular end-systolic volume. Fewer myocardial infarctions, deaths, readmissions for heart failure, and repeat revascularizations were additional benefits. Encouraging clinical findings have been reported using satellite or bone marrow stem cells, but understanding of the benefit mechanisms demands additional studies. Adult mammalian ventricular myocardium lacks adequate regeneration capability, and cellular cardiomyoplasty offers a new way to overcome this; the poor retention and engraftment rate and high apoptotic rate of the implanted stem cells limit outcomes. The ideal type and number of cells, optimal timing of cell therapy, and ideal cell delivery method depend on determining the beneficial mechanisms. Cellular cardiomyoplasty has progressed rapidly in the last decade. A critical review may help us to better plan the future direction.

Inflammation as a therapeutic target in heart failure? A scientific statement from the Translational Research Committee of the Heart Failure Association of the European Society of Cardiology

The increasing prevalence of heart failure poses enormous challenges for health care systems worldwide. Despite effective medical interventions that target neurohumoral activation, mortality and morbidity remain substantial. Evidence for inflammatory activation as an important pathway in disease progression in chronic heart failure has emerged in the last two decades. However, clinical trials of 'anti-inflammatory' therapies (such as anti-tumor necrosis factor-alpha approaches) have to date failed to show benefit in heart failure patients. The Heart Failure Association of the European Society of Cardiology recently organized an expert workshop to address the issue of inflammation in heart failure from a basic science, translational and clinical perspective, and to assess whether specific inflammatory pathways may yet serve as novel therapeutic targets for this condition. This consensus document represents the outcome of the workshop and defines key research questions that still need to be addressed as well as considering the requirements for future clinical trials in this area.

Stress, depression and cardiovascular dysregulation: a review of neurobiological mechanisms and the integration of research from preclinical disease models

Bidirectional associations between mood disorders and cardiovascular diseases are extensively documented. However, the precise physiological and biochemical mechanisms that underlie such relationships are not well understood. This review focuses on the neurobiological processes and mediators that are common to both mood and cardiovascular disorders. The discussion places an emphasis on the role of exogenous stressors in addition to: (a) neuroendocrine and neurohumoral changes involving dysfunction of the hypothalamic-pituitary-adrenal axis and the activation of the renin-angiotensin-aldosterone system, (b) immune alterations including activation of pro-inflammatory cytokines, (c) autonomic and cardiovascular dysregulation including increased sympathetic drive, withdrawal of parasympathetic tone, cardiac rate and rhythm disturbances, and altered baroreceptor reflex function, (d) central neurotransmitter system dysfunction involving the dopamine, norepinephrine and serotonin systems, and (e) behavioral changes including fatigue and physical inactivity. The review also discusses experimental investigations using preclinical disease models to elucidate the neurobiological mechanisms underlying the link between mood disorders and cardiovascular disease. These include: (a) the chronic mild stress model of depression, (b) a model of congestive heart failure, (c) a model of cardiovascular deconditioning, (d) pharmacological manipulations of body fluid and sodium balance, and (e) pharmacological manipulations of the central serotonergic system. In combination with an extensive human research literature, the investigation of mechanisms underlying mood and cardiovascular regulation using animal models will enhance understanding the association between depression and cardiovascular disease. This will ultimately promote the development of better treatments and interventions for individuals with co-morbid psychological and somatic pathologies.

Biology of TNFalpha and IL-10, and their imbalance in heart failure

Our understanding of the multiple in vivo functions of the proinflammatory cytokine, tumor necrosis factor (TNFalpha), is advancing at a rapid pace. In addition to its antitumor effects, overproduction of TNFalpha provokes tissue injury and organ failure. TNFalpha has also been shown to be cardiodepressant and responsible for various cardiovascular complications. It appears that still much needs to be learned for a full comprehension of the role of TNFalpha in heart biology. Another cytokine, interleukin-10 (IL-10), has been shown to have anti-inflammatory properties. It is suggested to counterbalance many adverse effects of TNFalpha. IL-10 suppresses the production of TNFalpha and many other proinflammatory cytokines. TNFalpha-induced oxidative stress is also known to be mitigated by IL-10. Moreover, improvement in cardiac function after treatment with various drugs is also shown to be associated with an increase in IL-10 content. Based on the data reviewed in here, it is suggested that an optimal balance between IL-10 and TNFalpha may be a new therapeutic strategy for a healthier heart.

Mechanisms underlying altered mood and cardiovascular dysfunction: the value of neurobiological and behavioral research with animal models

A bidirectional association between mood disorders and cardiovascular diseases has been described in humans, yet the precise neurobiological mechanisms that underlie this association are not fully understood. This article is focused on neurobiological processes and mediators in mood and cardiovascular disorders, with an emphasis on common mechanisms including stressor reactivity, neuroendocrine and neurohumoral changes, immune alterations, autonomic and cardiovascular dysregulation, and central neurotransmitter and neuropeptide dysfunction. A discussion of the utility of experimental investigations with rodent models, including those in rats and prairie voles (Microtus ochrogaster), is presented. Specific studies using these models are reviewed, focusing on the analysis of behavioral, physiological and neural mechanisms underlying depressive disorders and cardiovascular disease. Considered in combination with studies using human samples, the investigation of mechanisms underlying depressive behaviors and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and will promote the development of improved interventions for individuals with these detrimental disorders.

Protection against myocardial ischemia/reperfusion injury in TLR4-deficient mice is mediated through a phosphoinositide 3-kinase-dependent mechanism

TLRs play a critical role in the induction of innate and adaptive immunity. However, TLRs have also been reported to mediate the pathophysiology of organ damage following ischemia/reperfusion (I/R) injury. We have reported that TLR4(-/-) mice show decreased myocardial injury following I/R; however, the protective mechanisms have not been elucidated. We examined the role of the PI3K/Akt signaling pathway in TLR4(-/-) cardioprotection following I/R injury. TLR4(-/-) and age-matched wild-type (WT) mice were subjected to myocardial ischemia for 45 min, followed by reperfusion for 4 h. Pharmacologic inhibitors of PI3K (wortmannin or LY294002) were administered 1 h before myocardial I/R. Myocardial infarct size/area at risk was reduced by 51.2% in TLR4(-/-) vs WT mice. Cardiac myocyte apoptosis was also increased in WT vs TLR4(-/-) mice following I/R. Pharmacologic blockade of PI3K abrogated myocardial protection in TLR4(-/-) mice following I/R. Specifically, heart infarct size/area at risk was increased by 98% in wortmannin and 101% in LY294002-treated TLR4(-/-) mice, when compared with control TLR4(-/-) mice. These data indicate that protection against myocardial I/R injury in TLR4(-/-) mice is mediated through a PI3K/Akt-dependent mechanism. The mechanisms by which PI3K/Akt are increased in the TLR4(-/-) myocardium may involve increased phosphorylation/inactivation of myocardial phosphatase and tensin homolog deleted on chromosome 10 as well as increased phosphorylation/inactivation of myocardial glycogen synthase kinase-3beta. These data implicate innate immune signaling pathways in the pathology of acute myocardial I/R injury. These data also suggest that modulation of TLR4/PI3K/Akt-dependent signaling pathways may be a viable strategy for reducing myocardial I/R injury.

Central haemodynamics and peripheral muscle function during exercise in patients with chronic heart failure

In this narrative review of the current literature, we examine the central and peripheral mechanisms responsible for the exercise intolerance of chronic heart failure and highlight briefly the benefits of exercise training in the treatment of this debilitating disorder. Specifically, we identify the common finding of reduced cardiac output reserve during exercise conditions leading to decreased exercise tolerance. We also reveal that the stroke volume response to exercise varies depending on the individual patient, the presence of mitral regurgitation, and the aetiology of heart failure. Chronic heart failure patients with left ventricular systolic dysfunction appear able to use the Frank-Starling mechanism to compensate (in part) for their decreased contractile reserve. Patients with left ventricular diastolic dysfunction have normal contractile function; however, they are unable to make use of the Frank-Starling mechanism during exercise conditions. We also reveal that pericardial constraint may limit diastolic filling and exercise capacity in patients with chronic heart failure. It appears that interventions that reduce pericardial constraint and mitral regurgitation enhance diastolic filling and increase exercise tolerance. A series of peripheral muscle changes also occur, including changes in muscle mass, cellular structure, energy metabolism, and blood flow. Each of these factors is associated with decreased exercise capacity and the symptoms of chronic heart failure. Exercise training has been shown to improve both central haemodynamics and peripheral muscle function leading to improvements in exercise capacity, functional status, and overall quality of life in patients with chronic heart failure.

Statin therapy in cardiovascular diseases other than atherosclerosis

Statins are drugs that inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, thereby blocking the synthesis of cholesterol. Since being discovered in Japan in the mid 1970s, statins have been widely used to lower low-density lipoprotein cholesterol. However, analysis of cardiovascular research has revealed other important effects beyond changes in lipid parameters, referred to as pleiotropic effects. This paper focuses on the effects of statins as anti-ischemic agents with improvement in endothelial function, along with studies on valvular aortic stenosis, atrial fibrillation, heart failure, peripheral arterial disease, and cancer. As the evolution of statin research continues, there appear to be new potential benefits from statins to be found in many facets of cardiovascular disease.

Effects of carvedilol on M2 receptors and cholinesterase-positive nerves in adriamycin-induced rat failing heart

Heart failure is correlated with attenuation of parasympathetic nervous function and enhanced sympathetic activity. Carvedilol, a third-generation beta-blocker, may improve the prognosis of heart failure better than selective beta(1)-blockers. Not all of its effects, however, can be explained by direct actions on the sympathetic nervous system. This study was therefore performed to investigate the possible alterations of muscarinic cholinergic (M)(2) receptors and cholinesterase-positive nerves in different regions of the adriamycin-induced failing rat heart, and the potential effects of carvedilol on these M(2) receptors and cholinesterase-positive nerves. Karnovsky-Roots histochemical staining combined with point counting methods, and immunochemical streptavidin-biotin complex staining and image analysis were used to test the distribution of cholinesterase-positive nerves and the expression of M(2) receptors, respectively. Our results show that the cholinesterase-positive nerve system was downregulated in the adriamycin-induced failing heart group, while the density of M(2) receptors was increased in the carvedilol 3- and 10-mg/kg body weight groups, especially in the endocardial tissues of the left-ventricular free wall. It is concluded that upregulation of M(2) receptors may be one of the potential mechanisms by which carvedilol exert its action on heart failure.

NO-cGMP and TNF-alpha counter regulatory system in blood: understanding the mechanisms leading to myocardial dysfunction and failure

One of the major conceptual advances in the understanding of the pathogenesis of heart failure has been the insight that myocardial dysfunction and heart failure may progress as the result of the sustained over-expression of nitric oxide (NO) metabolites locally and in blood modulated by inducible nitric oxide synthase (iNOS). This by virtue of their deleterious effects is sufficient to contribute to disease progression by provoking left ventricular (LV) remodeling, hypertrophy and progressive LV dysfunction. Recently, tumor necrosis factor-alpha (TNF-alpha) has also been identified in this setting of heart failure. Analogous to the situation with NO, the over-expression of TNF-alpha is sufficient to contribute to disease progression in heart failure phenotype. Although important interactions between TNF-alpha and the NO have been recognized in the cardiovascular system for over a decade, the nature and importance of the interactions between these biologically active molecules in cardiac hypertrophy has become apparent only in the recent times. Therefore, we focused on the prevailing updated evidence which suggests that there is a functionally significant cross-regulation between NO and TNF-alpha signaling in blood thus playing a part in cardiac hypertrophy and failure. The discussions presented here will have a bearing on the therapeutic potential via inhibitors of these pathways in reducing cardiomyocyte hypertrophy and the LV dysfunction.

Modulation of the phosphoinositide 3-kinase signaling pathway alters host response to sepsis, inflammation, and ischemia/reperfusion injury

The phosphoinositide 3-kinases (PI3Ks) are a conserved family of signal transduction enzymes that are involved in regulating cellular activation, inflammatory responses, chemotaxis, and apoptosis. We have discovered that a carbohydrate ligand, glucan, will stimulate the endogenous PI3K/Akt signaling pathway. This article reviews the current data on the role of the PI3K/Akt signaling pathway as a negative feedback mechanism or compensatory regulator of septic and inflammatory responses. Of greater importance, the data reviewed in this article suggest that modulation of the PI3K/Akt signaling pathway can reduce the morbidity and mortality associated with septic and I/R injury. Thus, manipulation of the endogenous PI3K/Akt signaling pathway may represent a new and novel therapeutic approach to management of important diseases.

Cardioprotective effect of des-Aspartate-angiotensin-I (DAA-I) on cytokine gene expression profile in ligation model of myocardial infarction

We investigate the influence of des-Aspartate-angiotensin-I (DAA-I) on the cytokine expression profile in a rodent model of myocardial infarction. Myocardial infarction model was created in female Wistar rats by coronary artery ligation. Animals were randomized to receive intravenously either a daily dose of 1.2 mug DAA-I/kg body weight (group 1; n = 60) or saline (group 2; n = 60) for 14 days after infarction. Heart function was assessed by echocardiography. Animals were euthanized at 1, 3, 7, 14 and 31 days. Morphometric analysis using tetrazolium chloride staining revealed that infarct size was reduced by 32.2% (p < 0.05) in group 1 after 14 days of DAA-I treatment. Left ventricular ejection fraction in group 1 improved significantly (73.4%) as compared to group 2 (47.7%; p < 0.001). Immunostaining for immune cells at the infarct site showed that CD8+ lymphocytes infiltration at the infarct site declined in group 1 (15 +/- 5 cells) as compared to group 2 (50 +/- 6 cells; p < 0.001). Infiltration of monocytes and macrophages remained high at day 14 in group 2 (126 +/- 40 cells) as compared to group 1 (49 +/- 11 cells; p = 0.006). Multiplex PCR was done for differential gene expression of various pro-inflammatory cytokines. IL-6, TNF-alpha, TGF-beta and GM-CSF expression were significantly down-regulated in the infarct, peri-infarct and contra-lateral zones of the left ventricle in group 1 as compared to group 2. IL-6, TGF-beta and GM-CSF expression started to decline from day 1 of DAA-I treatment while TNF-alpha expression only reduced after 7 days of DAA-I treatment. We conclude that DAA-I prevented infarct expansion through suppression of inflammatory cytokines and immune cell infiltration in the infarct region.

PROTECTING THE PUMP: Controlling Myocardial Inflammatory Responses

Because of the anatomy, function, and nonregenerative nature of the myocardium, inflammation in this tissue is not well tolerated. Nevertheless, various diseases of the heart are characterized by inflammatory responses involving the effector mechanisms of innate and adaptive (lymphocyte-dependent) immunity. The innate immune response to ischemia-reperfusion injury is, by far, the most common cause of myocardial inflammation. Innate responses may have beneficial influences that preserve myocardial function in the short term but may be maladaptive in chronic states. Adaptive responses in the myocardium occur with infection or loss of tolerance, and lead to myocarditis. Given the narrow margin for benefit of cardiac inflammation, special regulatory mechanisms likely raise the threshold, compared to other tissues, for the induction and persistence of adaptive immune responses. These mechanisms include strong central and peripheral T cell tolerance to heart antigens and induction of anti-inflammatory feedback mechanisms involving cytokines such as interferon-gamma.

Gene transfection with human hepatocyte growth factor complementary DNA plasmids attenuates cardiac remodeling after acute myocardial infarction in goat hearts implanted with ventricular assist devices

BACKGROUND

Although a left ventricular assist device is often used to provide circulatory support until transplantation in severe heart failure, the mortality of long-term use of left ventricular assist devices remains high. We have shown that hepatocyte growth factor causes angiogenesis, antifibrosis, and antiapoptosis in the myocardium. Therefore, gene therapy with hepatocyte growth factor-complementary DNA plasmids may enhance the chance of "bridge to recovery." In this study, we performed gene therapy with hepatocyte growth factor in the impaired goat heart with a left ventricular assist device.

METHODS

Cardiac impairment was induced in 6 adult goats (56-65 kg) by ligation of the coronary artery, and ventricular assist devices were installed. The hepatocyte growth factor group (HGF; n = 3) was administered human hepatocyte growth factor-complementary DNA plasmid (2.0 mg) in the myocardium. The control group (n = 3) was similarly administered beta-galactosidase plasmid. Four weeks after gene transfection, we attempted to wean all goats from the ventricular assist device.

RESULTS

The myocardia transfected with human hepatocyte growth factor-complementary DNA contained human hepatocyte growth factor protein at levels as high as 1.0 +/- 0.3 ng/g tissue 3 days after transfection. After weaning from the ventricular assist device, the HGF group showed good hemodynamics, whereas the control group showed deterioration. The percentage of fractional shortening was significantly higher in the HGF group than the control group (HGF vs control, 37.9% +/- 1.7% vs 26.4% +/- 0.3%, respectively; P < .01). Left ventricular dilatation associated with myocyte hypertrophy and fibrotic changes was detected in the control group but not in the HGF group. Vascular density was markedly increased in the HGF group.

CONCLUSIONS

These results suggest that gene therapy with human hepatocyte growth factor may enhance the chance of bridge to recovery in the impaired heart supported with a ventricular assist device.

The role of inflammation in atherothrombosis: implications for clinical practice

Inflammation plays a key role in atherothrombosis: in the development of plaques, plaque rupture and thrombus formation. Various biochemical substances have been shown to be involved in the inflammatory process, some with pro-inflammatory activity and others with anti-inflammatory activity. Increased expression of many inflammatory mediators (e.g. C-reactive protein, CD40 ligand, P-selectin and IL-6) has been shown to correlate with increased risk of atherothrombotic events. One possible strategy for primary and secondary prevention is likely to focus on minimizing the inflammatory response and tipping the balance in favour of anti-inflammatory mediators and, therefore, plaque stability.

Cardiac remodeling and failure: from molecules to man (Part I)

The process of heart failure appears to be a common and coordinated response to cardiac injury and dysfunction. The contemporary mechanistic viewpoint that predictable, shared, highly regulated events underlie the complex heart failure process implies that an improved understanding of these mechanisms is fundamental to the advancement of cardiovascular biology and the subsequent development of targeted, effective treatment strategies for patients with congestive heart failure (CHF). Cardiac remodeling (CR) is the restructuring and reshaping of the heart that underlies heart failure progression. CR is a major determinant of the clinical course of CHF, irrespective of its etiology. The traditional concepts of cellular remodeling in the failing heart are based on well-established data indicating characteristic alterations in cell size, shape, and the ability to perform contractile work. The role of programmed cell death and the exciting possibility of cardiomyocyte regeneration are areas of intense investigation. Notably, the accumulating data in both animal and human hearts suggesting cardiomyocyte regeneration and renewal indicate that cellular remodeling is a complex and dynamic process that is not completely understood. For the development of new treatments to regenerate and restore failing myocardium, the possibilities offered by controlling cell death and enhancing cell renewal as a therapeutic target are unprecedented. Based on a critical review of the available literature, the traditional concepts and mechanisms describing the regulation of remodeling are largely inadequate. The neurohormonal (RAAS and adrenergic systems) and innovative cytokine hypothesis (TNF-alpha and others) of remodeling and failure do not account for all the cellular and molecular changes that result in the progression of CHF. Given that these contemporary concepts serve as the basis for the majority of our current heart failure treatments, it is not surprising that CHF is an emerging epidemic in our society. To define new therapeutic targets and to control the process of remodeling, novel biomolecules and mechanisms for the coordinated control of CR must be further defined.

p38 MAP Kinase Mediates Inflammatory Cytokine Induction in Cardiomyocytes and Extracellular Matrix Remodeling in Heart

Background— Increasing evidence suggests that development of heart failure involves activation of stress-response inflammatory cytokines, including tumor necrosis factor-α and interleukin-6. Yet, the myocyte contribution to their induction in failing hearts and the underlying regulatory mechanism in stressed myocardium remain unclear.

Methods and Results— In cultured cardiac myocytes, specific activation of stress-activated mitogen-activated protein kinase, p38, by upstream activator MKK6bE led to significant induction of tumor necrosis factor-α and interleukin-6 secretion, whereas treating cells with a selective p38 inhibitor (SB239068) significantly blocked the cytokine secretion from myocytes and increased their intracellular accumulation. Targeted expression of MKK6bE in transgenic hearts also resulted in a marked elevation in plasma tumor necrosis factor-α and interleukin-6; oral administration of SB239068 resulted in a significant reduction in their plasma levels but an increase in intracardiac accumulation of both cytokines. MKK6bE transgenic hearts developed marked interstitial fibrosis with increased matrix metalloproteinase abundance and selective induction of tissue inhibitor of matrix metalloproteinase-1; this extracellular matrix remodeling was also significantly attenuated by p38 inhibition. Along with cytokine induction and extracellular remodeling, MKK6bE transgenic animals displayed impaired hemodynamic function, whereas p38 inhibition improved the cardiac performance and prolonged the survival of the animals.

Conclusions— Stress-activated p38 kinase is a critical regulator of inflammatory response in cardiomyocytes with significant contribution to pathological remodeling in stressed myocardium. Inhibition of p38 may represent a useful therapeutic avenue to ameliorate cardiac pathology and heart failure evolution.

Neuroendocrine and cytokine profile of chronic mild stress-induced anhedonia

A bidirectional relationship exists between depression and cardiovascular disease. Patients with major depression are more likely to develop cardiac events, and patients with myocardial infarction and heart failure are more likely to develop depression. A feature common to both clinical syndromes is activation of proinflammatory cytokines and stress hormones, including the hypothalamic-pituitary-adrenal axis and the renin-angiotensin-aldosterone system. In the present study we examined the hypothesis that exposure to chronic mild stress (CMS), an experimental model of depression that induces anhedonia in rats, is sufficient to activate the production of proinflammatory cytokines and stress hormones that are detrimental to the heart and vascular system. Four weeks of exposure of male, Sprague-Dawley rats to mild unpredictable environmental stressors resulted in anhedonia which was operationally defined as a reduction in sucrose intake without a concomitant effect on water intake. Humoral assays indicated increased plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), plasma renin activity, aldosterone, and corticosterone in the CMS exposed rats. Tissue TNF-alpha and IL-1beta were increased in the hypothalamus, and TNF-alpha was increased in the pituitary gland. These humoral responses to CMS, associated with anhedonia as an index of depression in the rat, are likely to be associated with neurohumoral mechanisms that may contribute to adverse cardiac events. The findings provide a basis for examining more directly the interactions among the central, endocrine, and immune systems in depression associated with heart disease.

The "Statinth" wonder of the world: a panacea for all illnesses or a bubble about to burst

After the introduction of statins in the market as effective lipid lowering agents, they were shown to have effects other than lipid lowering. These actions were collectively referred to as 'pleiotropic actions of statins.' Pleiotropism of statins formed the basis for evaluating statins for several indications other than lipid lowering. Evidence both in favour and against is available for several of these indications. The current review attempts to critically summarise the available data for each of these indications.

Rheumatic heart disease: proinflammatory cytokines play a role in the progression and maintenance of valvular lesions

Heart lesions of rheumatic heart disease (RHD) patients contain T-cell clones that recognize heart proteins and streptococcal M peptides. To functionally characterize heart-infiltrating T lymphocytes, we evaluated their cytokine profile, both directly in situ and in T-cell lines derived from the heart (HIL). Interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, and IL-10 expressions were characterized in 20 heart tissue infiltrates from 14 RHD patients by immunohistochemistry. IFN-gamma-, TNF-alpha-, and IL-10-positive cells were consistently predominant, whereas IL-4 was scarce in the valves. In agreement with these data, the in vitro experiments, in which 13 HILs derived from heart samples of eight patients were stimulated with M5 protein and the immunodominant M5 (81-96) peptide, IL-4 was detected in HIL derived from the atrium (three of six) but not from the valve (zero of seven). IFN-gamma and IL-10 production were detected in culture supernatants in 11 of 13 and 6 of 12 HILs, respectively. The predominant IFN-gamma and TNF-alpha expression in the heart suggests that Th1-type cytokines could mediate RHD. Unlike in reversible myocardium inflammation, the significantly lower IL-4 expression in the valvular tissue (P = 0.02) may contribute to the progression of the RHD leading to permanent valvular damage (relative risk, 4.3; odds ratio, 15.8). The lack of IL-4 in vitro production by valve-derived HIL also emphasizes the more severe tissue destruction in valves observed in RHD.

trans fatty acids and systemic inflammation in heart failure

BACKGROUND

trans fatty acid (TFA) intake increases systemic inflammation in healthy persons. However, the effect in patients with established heart disease is unknown.

OBJECTIVE

Our aim was to determine whether TFAs are associated with systemic inflammation in patients with established heart disease.

DESIGN

Red blood cell membrane TFAs, a biomarker of dietary intake, and inflammatory marker concentrations were ascertained in 86 ambulatory patients with established heart failure. Associations between TFA levels and inflammatory markers were evaluated by linear regression.

RESULTS

Mean (+/-SD) TFA levels were 1.8 +/- 0.4% of membrane fatty acids (range: 0.7-2.9%). For each inflammatory marker, associations are presented as the absolute difference and percentage difference from the mean for each 1% higher membrane TFA level. After adjustment for age, sex, body mass index, diabetes, smoking, ejection fraction, New York Heart Association class, ischemic etiology, statin use, and serum glucose, TFA levels were positively associated with interleukin (IL) 1beta (difference from mean: 0.38 pg/mL; percentage difference from mean: 66%; P=0.04), IL-1 receptor antagonist (4033 pg/mL; 297%; P=0.006), IL-6 (9.5 pg/mL; 123%; P=0.006), IL-10 (241 pg/mL; 183%; P=0.02), tumor necrosis factor (TNF) alpha (256 pg/mL; 249%; P=0.02), TNF receptor 1 (537 pg/mL; 41%; P=0.03), TNF receptor 2 (39 242 pg/mL; 247%; P=0.001), monocyte chemoattractant protein 1 (117 pg/mL; 119%; P=0.004), and brain natriuretic peptide (40 pg/mL; 57%; P=0.04). Further adjustments for other patient characteristics did not significantly alter the results.

CONCLUSION

TFAs are strongly associated with systemic inflammation in patients with heart disease, which suggests that attention to TFA intake may be important for secondary prevention efforts.

Haemostatic and inflammatory biomarkers in advanced chronic heart failure: role of oral anticoagulants and successful heart transplantation

Advanced chronic heart failure (CHF) is associated with abnormal haemostasis and inflammation, but it is not known how these abnormalities are related, whether they are modified by oral anticoagulants (OAT), or if they persist after successful heart transplantation. We studied 25 patients with CHF (New York Heart Association class IV, 10 of whom underwent heart transplantation) and 25 age- and sex-matched healthy controls by measuring their plasma levels of prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin (TAT) complexes, tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), D-dimer, factor VII (FVII), fibrinogen, von Willebrand factor (VWF), tumour necrosis factor (TNF), soluble TNF receptor II (sTNFRII), interleukin 6 (IL-6), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), endothelial-selectin (E-selectin) and thrombomodulin. CHF patients had higher plasma levels of TAT, D-dimer, t-PA, fibrinogen, VWF, TNF, IL-6, sTNFRII, sVCAM-1 (P = 0.0001), sICAM-1 (P = 0.003) and thrombomodulin (P = 0.007) than controls. There were significant correlations (r = 0.414-0.595) between coagulation, fibrinolysis, endothelial dysfunction and inflammation parameters, which were lower in those patients treated with OATs. Heart transplantation led to reductions in fibrinogen (P = 0.001), VWF (P = 0.05), D-dimer (P = 0.05) and IL-6 levels (P = 0.05), but all the parameters remained significantly higher (P = 0.01-0.0001) than in the controls. Advanced CHF is associated with coagulation activation, endothelial dysfunction and increased proinflammatory cytokine levels. Most of these abnormalities parallel each other, tend to normalize in patients treated with OATs and, although reduced, persist in patients undergoing successful heart transplantation, despite the absence of clinical signs of CHF.

Statin therapy is associated with lower mortality among patients with severe heart failure

Experimental considerations suggest both potential harm and benefit from statin therapy in patients with severe heart failure. However, relations of statin therapy with clinical outcomes in severe heart failure are not well established. Using data from the Prospective Randomized Amlodipine Survival Evaluation (PRAISE) trial, we evaluated associations of statin therapy with total mortality among 1,153 patients with severe heart failure (ejection fraction <30% and New York Heart Association class IIIB or IV symptoms) of ischemic and nonischemic etiologies. Statin therapy was administered to 134 patients (12%) during the study period. Over a 1.3-year mean follow-up, there were 413 deaths (29 deaths/100 person-years). Adjusting for age, gender, diabetes, smoking, heart failure etiology, ejection fraction, and New York Heart Association class, statin therapy was associated with a 62% lower risk of death (hazard ratio 0.38, 95% confidence interval 0.23 to 0.65), or 1 fewer death/5 patients taking statin therapy for 1 year. This association was not greatly altered by additional adjustment for a variety of other patient characteristics, including serum cholesterol levels. After propensity score analyses, statin therapy was still associated with a 48% lower risk of death (hazard ratio 0.52, 95% confidence interval 0.30 to 0.89). Although this observational study does not prove causality, further investigation of potential benefits of statins in patients with severe heart failure appears warranted.

Curcumin Ameliorates Left Ventricular Function in Rabbits with Pressure Overload: Inhibition of the Remodeling of the Left Ventricular Collagen Network Associated with Suppression of Myocardial Tumor Necrosis Factor-.ALPHA. and Matrix Metalloproteinase-2 Expression

OBJECTIVE

Curcumin is a wide-spectrum cellular protector with antiinflammatory, antioxidizant, and antifibrotic effects. This study was conducted to investigate its effects on myocardial collagen remodeling in pressure overloaded rabbits.

METHODS AND RESULTS

Pressure overloaded rabbits were established by partial abdominal aorta ligation. The rabbits were divided into the sham-operation group, vehicle group and curcumin group. Curcumin was administered orally at a dose of 100 mg/kg.d in 10 ml of 2.5% polyethylene glycol solution and the other 2 groups were given the same dose of polyethylene glycol solution. Compared with the vehicle group, left ventricular function in the curcumin group was significantly ameliorated, as indicated by decreased left ventricular end-diastolic pressure, left ventricle weight to body weight ratio, and the left ventricular posterior wall thickness. The collagen volume fraction in the curcumin group was also reduced. Myocardial tumor necrosis factor (TNF)-alpha and matrix metalloproteinase (MMP)-2 expression were significantly overexpressed in the vehicle group and markedly suppressed in the curcumin group at both the 4th and 8th weeks. At the end of the 8th week, the ejection fraction in the curcumin group was increased compared with that in the vehicle group.

CONCLUSION

Curcumin improved left ventricular function in pressure overloaded rabbits. This might be due to inhibition of collagen remodeling associated with suppression of myocardial expression of tumor necrosis factor-alpha, and matrix metalloproteinase-2.

Anemia predicts mortality in severe heart failure: the prospective randomized amlodipine survival evaluation (PRAISE)

OBJECTIVES

Our aim was to examine the relationships between serum hematocrit (Hct) and risk of all-cause mortality among patients with severe heart failure (HF).

BACKGROUND

Anemia occurs with increased frequency in severe HF. However, few studies have examined the impact of anemia on mortality in this population.

METHODS

Using a prospective cohort design, we evaluated the relationships between baseline serum Hct and mortality among 1,130 patients with left ventricular EF <30% and New York Heart Association functional class IIIB or IV HF treated with angiotensin-converting enzyme inhibitors, diuretics, and digitalis. Mortality was ascertained by centralized adjudication.

RESULTS

The mean Hct was 41.8% (range 25.4% to 58.8%). Over 15 months of mean follow-up, there were 407 deaths (29 per 100 person-years). After adjustment for potential confounders, those in the lowest quintile of Hct (range 25.4% to 37.5%) had a 52% higher risk of death (hazard ratio 1.52, 95% confidence interval 1.11 to 2.10), compared with the highest quintile (range 46.1% to 58.8%). Within the lowest quintile of Hct, each 1% decrease in Hct was associated with an 11% higher risk of death (p < 0.01), whereas within the four higher quintiles of Hct, Hct was not associated with total mortality. Evaluation of different causes of death indicated that a lower Hct was strongly associated with death from progressive HF, rather than sudden death or other deaths.

CONCLUSIONS

Among patients with severe HF, anemia is a significant independent risk factor for death, with a progressively higher risk with increasing severity of anemia. Further investigation of the etiologies, prevention, and treatment of anemia in severe HF is warranted.

Leukemia inhibitory factor is augmented in the heart in experimental heart failure

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that induces cardiac myocyte hypertrophy through the signal transducing molecule, glycoprotein 130. To date, localization of LIF in the heart and regulation of cardiac LIF expression in congestive heart failure (CHF) remain undefined. The present study investigates the potential activation of LIF expression in the failing canine heart that was produced by progressive rapid ventricular pacing. Immunohistochemistry for LIF revealed that LIF immunoreactivity was present in the atrial and ventricular myocytes of the normal heart and was markedly increased in the failing heart as compared to the normal heart. Northern blot analysis demonstrated that cardiac LIF mRNA was increased in both atrium and ventricle in CHF as compared to the normal heart (P<0.01). Linear regression analysis revealed a positive correlation between atrial LIF mRNA and atrial pressure (r=0.87, P<0.001 in right atrium and r=0.86, P<0.001 in left atrium). Positive correlations between left ventricular LIF mRNA and left ventricular dimensions (r=0.91, P<0.0001 in end-systolic diameter; r=0.86, P<0.001 in end-diastolic diameter), and an inverse correlation between left ventricular LIF mRNA and left ventricular ejection fraction (EF) were observed (r=-0.93, P<0.0001). There was a positive correlation between left ventricular LIF mRNA and left ventricular mass index (LVMI) (r=0.85, P<0.001). The present study demonstrates that cardiac LIF immunoreactivity and its gene expression are increased in a canine model of experimental CHF and suggests a potential role for LIF in the pathophysiology of CHF.

Cytokine mediation of experimental heart failure-induced anhedonia

Immune system dysfunction is hypothesized to influence several disease states, including cardiovascular disease and psychological depression. The comorbidity of depression and coronary artery disease may be influenced by immune system-brain interactions involving proinflammatory cytokines. The present studies evaluated an index of depression in a rodent model of heart failure by measuring responses to rewarding electrical brain stimulation, which provides an experimental procedure to operationally define anhedonia in rats. Heart failure led to a rightward shift in the current-response relationship in the brain stimulation paradigm, indicative of reduced rewarding properties of the brain stimulation (i.e., anhedonia). Acute treatment with a tumor necrosis factor antagonist, etanercept, reduced circulating tumor necrosis factor- levels in rats with heart failure and restored responding for electrical brain stimulation. The current findings have implications for the study of pathophysiological mechanisms underlying the association of cardiovascular disease and depression.

Neurohumoral activation and ventricular arrhythmias in patients with decompensated congestive heart failure: role of endothelin

Patients with congestive heart failure (CHF) have a high incidence of ventricular arrhythmias and sudden arrhythmic death. CHF entails profound and complex abnormalities in humoral responses that are thought to promote arrhythmic events. However, it is unknown which of the many endogenous mediators that accumulate as part of neurohormonal activation is important in arrhythmogenesis in the setting of CHF. The study included 83 patients admitted to the hospital for treatment of decompensated CHF. Neurohormonal and cytokine activation was assessed by measuring plasma renin activity, aldosterone, norepinephrine, endothelin-1, tumor necrosis factor-alpha, and interleukin-6 levels. Atrial and ventricular arrhythmic events were assessed by 24-hour Holter monitoring. In a univariate analysis, a highly significant, positive relationship was found between plasma endothelin-1 levels and the average hourly total premature ventricular beats (P = 0.003), the frequency of ventricular pairs (P = 0.0003), and the frequency of ventricular tachycardia episodes (P = 0.001). After inclusion of clinical variables, drug therapies, neurohormones, and cytokine levels in a multivariate analysis, the positive relationship between plasma endothelin-1 level and the average hourly total premature ventricular beats (P = 0.008), the frequency of ventricular pairs (P = 0.007), and ventricular tachycardia episodes (P = 0.009) remained independent. No association between other neurohormones or cytokines and arrhythmic events was demonstrated. The results of the present study suggest that increased endothelin-1 concentrations may be involved in promoting the occurrence of ventricular ectopy in patients with decompensated CHF. Proarrhythmic effects may account, in part, for the poor outcome associated with increased endothelin-1 levels in patients with decompensated CHF.

Cytokines in depression and heart failure

OBJECTIVE

There is a convincing body of evidence linking depression, cardiovascular disease, and mortality. There is also growing evidence that depression is a risk factor for congestive heart failure (CHF) and that CHF patients with major depression have higher rates of mortality and repeat hospitalizations. Currently there are no proposed neurobiological or neuroimmune mechanisms for the comorbidity of heart failure and depression.

METHODS

This review focuses on the recent literature about the role of cytokines in CHF and depression as separate conditions. This review also attempts to identify the overlapping immunological mechanisms that have a potential for future research in the pathophysiology of comorbid depression and CHF.

RESULTS

Results of current studies suggest that cytokines exert deleterious effects on the heart and that soluble tumor necrosis factor (TNF) receptor 2 leads to reversal of the cardiotoxic effects of TNF, although the clinical significance of this is unclear. Major depression has been associated with alteration of various aspects of the innate immune system, including cellular components (such as microphages, neutrophils, and natural killer cells) and soluble mediators (such as acute-phase reaction proteins and cytokines). It is inconclusive whether antidepressants have immunoregulatory effects.

CONCLUSIONS

The literature has not yet addressed the role of cytokines in comorbid depression and CHF. But cytokines may provide a new avenue in understanding brain-body interaction in depression and heart failure.

Pathogenetic basis of myocardial dysfunction and amenability to reversal

As the role of the LVAD graduates from the "bridge-to-transplant" to the "bridge-to-recovery," several important issues need to be answered. Such a paradigm would require a definition of appropriate candidates for LVAD implantation, the most appropriate time for LVAD placement during the management of end-stage CHF, reliable histologic, biochemical, and imaging markers of recovery, and the optimum duration of LVAD support. The device technology must be refined further to reduce the morbidity associated with the device itself, and to make the device smaller, less invasive, and less thrombogenic. It will be a challenge to identify the role for concomitant drug therapy and to develop weaning programs for device support. Finally, guidelines will have to be developed to monitor and manage these patients after explantation of LVAD.

Human intestinal epithelial and smooth muscle cells are potent producers of IL-6

BACKGROUND

Interleukin-6 (IL-6), a pluripotent cytokine, has traditionally been considered the product of proinflammatory cells. However, many other cell types have been shown to produce IL-6. Since intestinal inflammation is commonly associated with a vigorous systemic inflammatory response, we hypothesized that intestinal epithelial and smooth muscle cells might contribute to that response by producing IL-6. We therefore studied the capacity of differentiated human intestinal epithelial and smooth muscle cell lines to produce IL-6 in response to various proinflammatory stimuli.

MATERIALS AND METHODS

CCL-241, a human intestinal epithelial cell line, and HISM, a human intestinal muscle cell line, were grown to confluency and then treated for 24 h with various concentrations of lipopolysaccharide, Clostridium difficile culture extract containing both toxin A and toxin B, recombinant human tumor necrosis factor-alpha (TNF-alpha), or recombinant human interleukin-1 beta (IL-1beta). Supernatants were then collected for IL-6 determination using an enzyme-linked immunosorbent assay. Cell numbers were determined using a Coulter counter. For comparison, parallel studies were performed using phorbol ester-primed U-937 and THP-1 human macrophage cell lines.

RESULTS

Both human intestinal epithelial and smooth muscle cells produced IL-6 under basal conditions. In HISM cells, but not in CCL-241 cells, IL-6 release was increased slightly by treatment with C. difficile culture extract containing both toxin A and toxin B and with lipopolysaccharide. In both cell lines, IL-6 production was profoundly stimulated by treatment with IL-1beta and less so with TNF-alpha. Combinations of high-dose TNF-alpha and IL-1beta may have a slightly additive, but not synergistic, effect on IL-6 release. The amount of IL-6 produced by IL-1-stimulated intestinal cell lines was 70-fold higher than that produced by stimulated macrophage cell lines. CONCLUSIONS; Both intestinal epithelial and smooth muscle cells demonstrate the ability to release significant amounts of IL-6. The profound response to IL-1beta and TNF-alpha stimulation by both cell lines suggests that human intestinal parenchymal cells, influenced by paracrine mediators liberated from proinflammatory cells, might significantly contribute to the overall systemic inflammatory response by producing IL-6.

Heart failure and the brain: new perspectives

Despite recent therapeutic advances, the prognosis for patients with heart failure remains dismal. Unchecked neurohumoral excitation is a critical element in the progressive clinical deterioration associated with the heart failure syndrome, and its peripheral manifestations have become the principal targets for intervention. The link between peripheral systems activated in heart failure and the central nervous system as a source of neurohumoral drive has therefore come under close scrutiny. In this context, the forebrain and particularly the paraventricular nucleus of the hypothalamus have emerged as sites that sense humoral signals generated peripherally in response to the stresses of heart failure and contribute to the altered volume regulation and augmented sympathetic drive that characterize the heart failure syndrome. This brief review summarizes recent studies from our laboratory supporting the concept that the forebrain plays a critical role in the pathogenesis of ischemia-induced heart failure and suggesting that the forebrain contribution must be considered in designing therapeutic strategies. Forebrain signaling by neuroactive products of the renin-angiotensin system and the immune system are emphasized.

Evolving strategies for surgical management of patients with severe left ventricular dysfunction

As a result of an increasing population with advanced congestive heart failure and the lack of growth in cardiac transplantation, surgical treatments for heart failure have been re-examined. These therapies represent the evolution of well-known operations such as coronary bypass surgery and valve surgeries, and the more novel left ventricular reconstruction and operations aimed at inhibiting left ventricular remodeling. When performed by surgeons with experience in this evolving speciality within cardiovascular surgery, surgery for advanced heart failure is a treatment of choice for many patients.

Chronic heart failure and the immune system

Several lines of evidence support a role of immune mechanisms in the pathogenesis of chronic heart failure (CHF). Proinflammatory cytokines (interleukin-1, -2, -6, and tumor necrosis factor) and chemokines are involved in cardiac depression and in the progression of heart failure. Other components believed to be relevant to the pathogenesis of CHF are adhesion molecules, autoantibodies, nitric oxide (NO), and endothelin-1. The origin of the immune activation in patients with CHF is still unknown, however two hypotheses have been proposed on the basis of experimental and clinical data. One suggests that the bowel wall edema leads to bacterial translocation with subsequent endotoxin release and immune activation. The second suggests that the heart in CHF is the main source of cytokines, as is shown by the fact that TNF alpha is produced by the failing myocardium but not by a normal one. No single source of cytokine production (gut or heart) seems sufficient to fully explain the multiple organ involvement and the systemic inflammation of CHF, which is probably related to systemic hypoxia, a potent stimulus for activation of the immune system and for cytokine production. The effort of define the immune system's role has opened new perspectives of therapeutic strategies, such as anti-cytokine drugs, to treat CHF.

Inflammatory mediators and the failing heart: past, present, and the foreseeable future

Recent studies have identified the importance of proinflammatory mediators in the development and progression of heart failure. The growing appreciation of the pathophysiological consequences of sustained expression of proinflammatory mediators in preclinical and clinical heart failure models culminated in a series of multicenter clinical trials that used "targeted" approaches to neutralize tumor necrosis factor in patients with moderate to advanced heart failure. However, these targeted approaches have resulted in worsening heart failure, thereby raising a number of important questions about what role, if any, proinflammatory cytokines play in the pathogenesis of heart failure. This review will summarize the tremendous growth of knowledge that has taken place in this field, with a focus on what we have learned from the negative clinical trials, as well as the potential direction of future research in this area.