Serum but not myocardial TNF-alpha concentration is increased in pacing-induced heart failure in rabbits

The potential roles of exosomes in pathological cardiomyocyte hypertrophy mechanisms and therapy: A review

Pathological cardiac hypertrophy, characterized by the enlargement of cardiac muscle cells, leads to serious cardiac conditions and stands as a major global health issue. Exosomes, comprising small lipid bilayer vesicles, are produced by various cell types and found in numerous bodily fluids. They play a pivotal role in intercellular communication by transferring bioactive cargos to recipient cells or activating signaling pathways in target cells. Exosomes from cardiomyocytes, endothelial cells, fibroblasts, and stem cells are key in regulating processes like cardiac hypertrophy, cardiomyocyte survival, apoptosis, fibrosis, and angiogenesis within the context of cardiovascular diseases. This review delves into exosomes' roles in pathological cardiac hypertrophy, first elucidating their impact on cell communication and signaling pathways. It then advances to discuss how exosomes affect key hypertrophic processes, including metabolism, fibrosis, oxidative stress, and angiogenesis. The review culminates by evaluating the potential of exosomes as biomarkers and their significance in targeted therapeutic strategies, thus emphasizing their critical role in the pathophysiology and management of cardiac hypertrophy.

Age, sex, and inflammatory markers predict chronic conditions, cardiac disease, and mortality among captive western lowland gorillas (Gorilla gorilla gorilla)

In humans, inflammatory markers predict health risks. As great apes experience many similar conditions, measuring inflammation may provide valuable health information. We examined four serum inflammatory markers in zoo-housed gorillas (n = 48): albumin, CRP, IL-6, and TNF-α. We first analyzed age- and sex-associated patterns, then used multimodel inference to evaluate models with age, sex, and inflammatory markers as predictors of all-cause morbidity, cardiac disease, and mortality. Older gorillas had lower albumin and higher IL-6, and males had higher albumin, lower CRP, and lower TNF-α. All-cause morbidity was best predicted by age, sex, and TNF-α, but the second model containing only age and sex was equivalent. Cardiac disease was best predicted by TNF-α alongside age and sex, with lower levels associated with increased risk. When outliers were removed, the model with TNF-α was second to the model containing only age and sex. Finally, mortality risk was best predicted by the model with only age and sex. Other models containing individual inflammatory markers were within top model sets for each health outcome. Our results indicate that age and sex are robust for predicting all-cause morbidity and mortality risk in gorillas; while models which include individual inflammatory markers also predict risk, they may not improve predictions over age and sex alone. However, given the prevalence of cardiac disease in great apes, these results suggest that TNF-α warrants further investigation. With their potential to provide valuable health information, data on inflammatory markers may contribute to the care and management of gorillas in human care.

Ischemic Heart Disease Pathophysiology Paradigms Overview: From Plaque Activation to Microvascular Dysfunction

Ischemic heart disease still represents a large burden on individuals and health care resources worldwide. By conventions, it is equated with atherosclerotic plaque due to flow-limiting obstruction in large-medium sized coronary arteries. However, clinical, angiographic and autoptic findings suggest a multifaceted pathophysiology for ischemic heart disease and just some cases are caused by severe or complicated atherosclerotic plaques. Currently there is no well-defined assessment of ischemic heart disease pathophysiology that satisfies all the observations and sometimes the underlying mechanism to everyday ischemic heart disease ward cases is misleading. In order to better examine this complicated disease and to provide future perspectives, it is important to know and analyze the pathophysiological mechanisms that underline it, because ischemic heart disease is not always determined by atherosclerotic plaque complication. Therefore, in order to have a more complete comprehension of ischemic heart disease we propose an overview of the available pathophysiological paradigms, from plaque activation to microvascular dysfunction.

Complexity of TNF-α Signaling in Heart Disease

Heart disease is a leading cause of death with unmet clinical needs for targeted treatment options. Tumor necrosis factor alpha (TNF-α) represents a master pro-inflammatory cytokine that plays an important role in many immunopathogenic processes. Anti-TNF-α therapy is widely used in treating autoimmune inflammatory disorders, but in case of patients with heart disease, this treatment was unsuccessful or even harmful. The underlying reasons remain elusive until today. This review summarizes the effects of anti-TNF-α treatment in patients with and without heart disease and describes the involvement of TNF-α signaling in a number of animal models of cardiovascular diseases. We specifically focused on the role of TNF-α in specific cardiovascular conditions and in defined cardiac cell types. Although some mechanisms, mainly in disease development, are quite well known, a comprehensive understanding of TNF-α signaling in the failing heart is still incomplete. Published data identify pathogenic and cardioprotective mechanisms of TNF-α in the affected heart and highlight the differential role of two TNF-α receptors pointing to the complexity of the TNF-α signaling. In the light of these findings, it seems that targeting the TNF-α pathway in heart disease may show therapeutic benefits, but this approach must be more specific and selectively block pathogenic mechanisms. To this aim, more research is needed to better understand the molecular mechanisms of TNF-α signaling in the failing heart.

Hydrogen sulfide regulates circadian-clock genes in C2C12 myotubes and the muscle of high-fat-diet-fed mice

Hydrogen sulfide (H₂S) is an endogenous novel gasotransmitter which is implicated in the pathophysiology of the metabolic syndrome. Core clock genes (CCG) and its controlled genes disruption is implicated in the progression of metabolic syndrome. We examined whether H₂S has any effect on CCG in the skeletal muscle of mice fed a high-fat diet (HFD) and in myotubes. In the muscle of HFD-mice, the expression of H₂S biosynthesis enzyme genes (CSE, CBS, and 3-Mpst) along with antioxidant genes (GCLC, GCLM, GSS, and GSR) involved in GSH biosynthesis and recycling were reduced significantly, but the oxidative stress (OS) increased. Expression of the CCG (Bmal1, Clock, RORα, Cry2, Per2) and clock-controlled genes (PPARγ, PGC-1α, RXRα) was downregulated, whereas the levels of PPARα mRNA were upregulated. Similar to that in the muscle of HFD-mice, in vitro myotubes exposed to high glucose or palmitate to mimic metabolic syndrome, showed an increased OS and decreased in CSE mRNA, H₂S production and CCG mRNA levels were also downregulated. TNF and MCP-1 treatment on the myotubes was similar to that observed in HFD-muscle, with that the Rev-erbα mRNA was upregulated. Inhibition (siRNA/pharmacological inhibitors) of both CSE and GCLC (the rate-limiting enzyme in GSH biosynthesis) decreased H₂S, and increased OS; Bmal1 and Clock mRNA levels were downregulated, while Rev-erbα increased significantly in these conditions. CSE KD myotubes were post-treated with an H₂S donor partially restored the mRNA levels of core clock genes. These findings report that the deficiencies of H₂S/GSH impair expression of CCG and treatment with H₂S donor or GSH precursor exert a positive effect over CCG. Thus, suggest that H₂S as a new endogenous factor for regulating circadian clock, and its donors could provide a novel chrono-pharmacological therapy to manage metabolic disorders.

Glucose-6-phosphate dehydrogenase deficiency increases cell adhesion molecules and activates human monocyte-endothelial cell adhesion: Protective role of l-cysteine

Glucose-6-phosphate dehydrogenase is a major enzyme that supplies the reducing agent nicotinamide adenine dinucleotide phosphate hydrogen (NADPH), which is required to recycle oxidized/glutathione disulfide (GSSH) to reduced glutathione (GSH). G6PD-deficient cells are susceptible to oxidative stress and a deficiency of GSH. Endothelial dysfunction is characterized by the loss of nitric oxide (NO) bioavailability, which regulates leukocyte adhesion to endothelium. G6PD-deficient endothelial cells (EC) demonstrate reduced expression of endothelial nitric oxide synthase (eNOS) and NO levels along with reduced GSH. Whether G6PD deficiency plays any role in EC dysfunction is unknown. The chronic inflammation commonly seen in those with metabolic syndrome, characterized by elevated levels of tumor necrosis factor (TNF) and monocyte chemoattractant protein 1 (MCP-1), provided an incentive for investigation of these cytokines as well. A GSH/G6PD-deficient model was created using human umbilical vein endothelial cells (HUVEC) treated with either buthionine sulfoximine (BSO), a pharmacological inhibitor of the rate-limiting enzyme of GSH biosynthesis (γ-glutamylcysteine synthetase), or with 6-aminonicotinamide (6-AN), an inhibitor of G6PD or G6PD siRNA. Normal and G6PD-deficient cells were also treated with pro-atherosclerotic stimuli such as high glucose, TNF, and MCP-1. After inhibiting or knocking down G6PD/GSH, the capacity of endothelial cells for monocyte recruitment was assessed by determining the expression of the adhesion molecules intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), which was upregulated by G6PD deficiency and accompanied by the presence of the oxidative stress markers NADPH oxidase 4 (NOX4), inducible nitric oxide synthase (iNOS), and reactive oxygen species (ROS). Treatment with the inhibitors BSO and 6-AN caused increased levels of adhesion molecule mRNA and monocyte-EC adhesion. Following treatment with high glucose, G6PD-deficient cells showed an increase in levels of ICAM-1 and VCAM-1 mRNA, as well as monocyte-EC adherence, compared with results seen in control cells. Treatment with l-cysteine (a precursor of GSH) protected endothelial cells by increasing GSH and attenuating ROS, ICAM-1, VCAM-1, and monocyte-EC adhesion. These results suggest that G6PD/GSH deficiency plays a role in endothelial dysfunction and that supplementation with l-cysteine can restore GSH levels and reduce the EC activation markers in G6PD-deficient conditions.

Statin drugs mitigate cellular inflammatory response after ST elevation myocardial infarction, but do not affect in-hospital mortality

Introduction: The objective was to examine the role of statins in modulating post-STEMI inflammation and related mortality.

Methods: A total of 404 patients with STEMI were reviewed. Demographics, comorbidities, laboratory values, and outcomes were collected. The patients were grouped as STATIN and NOSTAT based on the use of statin drugs at the time of admission. Ninety-seven patients were receiving statin drugs.

Results: The patients in the STATIN group were more likely to be hypertensive (53.6%), diabetic (37.1%) and to have previous coronary revascularization (9.3%). Following propensity matching of 89 patients in STATIN group to an equal number of patients in NOSTAT controls had lower neutrophil count 7.8 (6.8-8.4) compared to those in the NOSTAT group 9.1 (7.9-10.1). Although there was no difference in-hospital mortality between the two groups, the incidence of pump failure was lower in the STATIN group (5.6% vs. 15.7%; P < 0.01).

Conclusion: Statin treatment prior to STEMI mitigates the cellular inflammatory response after the myocardial infarction, as evidenced by lower leukocyte and neutrophil cell counts in the STATIN group.

Dietary fat sources differentially modulate intestinal barrier and hepatic inflammation in alcohol-induced liver injury in rats

Endotoxemia is a causal factor in the development of alcoholic liver injury. The present study aimed at determining the interactions of ethanol with different fat sources at the gut-liver axis. Male Sprague-Dawley rats were pair fed control or ethanol liquid diet for 8 wk. The liquid diets were based on a modified Lieber-DeCarli formula, with 30% total calories derived from corn oil (rich in polyunsaturated fatty acids). To test the effects of saturated fats, corn oil in the ethanol diet was replaced by either cocoa butter (CB, rich in long-chain saturated fatty acids) or medium-chain triglycerides (MCT, exclusively medium-chain saturated fatty acids). Ethanol feeding increased hepatic lipid accumulation and inflammatory cell infiltration and perturbed hepatic and serum metabolite profiles. Ethanol feeding with CB or MCT alleviated ethanol-induced liver injury and attenuated ethanol-induced metabolic perturbation. Both CB and MCT also normalized ethanol-induced hepatic macrophage activation, cytokine expression, and neutrophil infiltration. Ethanol feeding elevated serum endotoxin level, which was normalized by MCT but not CB. In accordance, ethanol-induced downregulations of intestinal occludin and zonula occludens-1 were normalized by MCT but not CB. However, CB normalized ethanol-increased hepatic endotoxin level in association with upregulation of an endotoxin detoxifying enzyme, argininosuccinate synthase 1 (ASS1). Knockdown ASS1 in H4IIEC3 cells resulted in impaired endotoxin clearance and upregulated cytokine expression. These data demonstrate that the protection of saturated fats against alcohol-induced liver injury occur via different actions at the gut-liver axis and are chain length dependent.

Intrinsic skeletal muscle alterations in chronic heart failure patients: a disease-specific myopathy or a result of deconditioning?

Chronic heart failure (CHF) patients frequently experience impaired exercise tolerance due to skeletal muscle fatigue. Studies suggest that this in part is due to intrinsic alterations in skeletal muscle of CHF patients, often interpreted as a disease-specific myopathy. Knowledge about the mechanisms underlying these skeletal muscle alterations is of importance for the pathophysiological understanding of CHF, therapeutic approach and rehabilitation strategies. We here critically review the evidence for skeletal muscle alterations in CHF, the underlying mechanisms of such alterations and how skeletal muscle responds to training in this patient group. Skeletal muscle characteristics in CHF patients are very similar to what is reported in response to chronic obstructive pulmonary disease (COPD), detraining and deconditioning. Furthermore, skeletal muscle alterations observed in CHF patients are reversible by training, and skeletal muscle of CHF patients seems to be at least as trainable as that of matched controls. We argue that deconditioning is a major contributor to the skeletal muscle dysfunction in CHF patients and that further research is needed to determine whether, and to what extent, the intrinsic skeletal muscle alterations in CHF represent an integral part of the pathophysiology in this disease.

NF-κB in the paraventricular nucleus modulates neurotransmitters and contributes to sympathoexcitation in heart failure

Findings from our laboratory indicate that proinflammatory cytokines and their transcription factor, nuclear factor-kappaB (NF-κB), are increased in the hypothalamic paraventricular nucleus (PVN) and contribute towards the progression of heart failure. In this study, we determined whether NF-κB activation within the PVN contributes to sympathoexcitation via interaction with neurotransmitters in the PVN during the pathogenesis of heart failure. Heart failure was induced in rats by left anterior descending coronary artery ligation. Sham-operated control (SHAM) or heart failure rats were treated for 4 weeks through bilateral PVN infusion with SN50, SN50M or vehicle via osmotic minipump. Rats with heart failure treated with PVN vehicle or SN50M (inactive peptide for SN50) had increased levels of glutamate, norepinephrine (NE), tyrosine hydroxylase (TH), superoxide, gp91(phox) (a subunit of NAD(P)H oxidase), phosphorylated IKKβ and NF-κB p65 activity, and lower levels of gamma-aminobutyric acid (GABA) and the 67-kDa isoform of glutamate decarboxylase (GAD67) in the PVN compared with those of SHAM rats. Plasma levels of cytokines, norepinephrine, epinephrine and angiotensin II, and renal sympathetic nerve activity (RSNA) were increased in heart failure rats. Bilateral PVN infusion of SN50 prevented the decreases in PVN GABA and GAD67, and the increases in RSNA and PVN glutamate, norepinephrine, TH, superoxide, gp91(phox), phosphorylated IKKβ and NF-κB p65 activity observed in vehicle or SN50M-treated heart failure rats. A same dose of SN50 given intraperitoneally did not affect neurotransmitters concentration in the PVN and was similar to vehicle-treated heart failure rats. These findings suggest that NF-κB activation in the PVN modulates neurotransmitters and contributes to sympathoexcitation in rats with ischemia-induced heart failure.

TNFα in myocardial ischemia/reperfusion, remodeling and heart failure

TNFα is crucially involved in the pathogenesis and progression of myocardial ischemia/reperfusion injury and heart failure. The formation and release of TNFα and its downstream signal transduction cascade following activation of its two receptor subtypes are characterized. Myocardial TNFα and TNF receptor activation have an ambivalent role in myocardial ischemia/reperfusion injury and protection from it. Excessive TNFα expression and subsequent cardiomyocyte TNF receptor type 1 stimulation induce contractile dysfunction, hypertrophy, fibrosis and cell death, while a lower TNFα concentration and subsequent cardiomyocyte TNF receptor type 2 stimulation are protective. Apart from its concentration and receptor subtype, the myocardial action of TNFα depends on the duration of its exposure and its localization. While detrimental during sustained ischemia, TNFα contributes to ischemic preconditioning protection, no matter whether it is the first, second or third window of protection, and both TNF receptors are involved in the protective signal transduction cascade. Finally, the available clinical attempts to antagonize TNFα in cardiovascular disease, notably heart failure, are critically discussed.

Increased inducible nitric oxide synthase and arginase II expression in heart failure: no net nitrite/nitrate production and protein S-nitrosylation

Our objective was to address the balance of inducible nitric oxide (NO) synthase (iNOS) and arginase and their contribution to contractile dysfunction in heart failure (HF). Excessive NO formation is thought to contribute to contractile dysfunction; in macrophages, increased iNOS expression is associated with increased arginase expression, which competes with iNOS for arginine. With substrate limitation, iNOS may become uncoupled and produce reactive oxygen species (ROS). In rabbits, HF was induced by left ventricular (LV) pacing (400 beats/min) for 3 wk. iNOS mRNA [quantitative real-time PCR (qRT-PCR)] and protein expression (confocal microscopy) were detected, and arginase II expression was quantified with Western blot; serum arginine and myocardial nitrite and nitrate concentrations were determined by chemiluminescence, and protein S-nitrosylation with Western blot. Superoxide anions were quantified with dihydroethidine staining. HF rabbits had increased LV end-diastolic diameter [20.0 + or - 0.5 (SE) vs. 17.2 + or - 0.3 mm in sham] and decreased systolic fractional shortening (11.1 + or - 1.4 vs. 30.6 + or - 0.7% in sham; both P < 0.05). Myocardial iNOS mRNA and protein expression were increased, however, not associated with increased myocardial nitrite or nitrate concentrations or protein S-nitrosylation. The serum arginine concentration was decreased (124.3 + or - 5.6 vs. 155.4 + or - 12.0 micromol/l in sham; P < 0.05) at a time when cardiac arginase II expression was increased (0.06 + or - 0.01 vs. 0.02 + or - 0.01 arbitrary units in sham; P < 0.05). Inhibition of iNOS with 1400W attenuated superoxide anion formation and contractile dysfunction in failing hearts. Concomitant increases in iNOS and arginase expression result in unchanged NO species and protein S-nitrosylation; with substrate limitation, uncoupled iNOS produces superoxide anions and contributes to contractile dysfunction.

Circulating cytokine levels in mice with heart failure are etiology dependent

Objectives: The aim of this study was to examine whether alterations in circulating cytokine levels are dependent on the etiology of myocardial hypertrophy and heart failure (HF). Background: Several heart diseases are associated with altered levels of circulating cytokines. Cytokines are regarded as possible therapeutic targets or biomarkers, but such approaches are currently not in clinical use. If alterations in circulating cytokines are etiology dependent, this should be taken into consideration when using cytokines as disease markers and therapeutic targets. Methods: The serum levels of 25 cytokines were quantified with Luminex and/or ELISA in four murine models of heart disease: banding of the ascending aorta (AB) or the pulmonary artery (PB), myocardial infarction (MI), and a cardiomyopathy model with inducible cardiomyocyte-specific knockout of the sarco(endo)plasmatic reticulum Ca2+-ATPase (SERCA2KO). Results: No increase in circulating cytokine levels were found in mice 1 wk after AB, although substantial myocardial hypertrophy was present. After 1 wk of MI, only interleukin (IL)-18 was increased. In the SERCA2KO mice with HF, circulating levels of IL-1α, IL-2, IL-3, IL-6, IL-9, IL-10, IL-12p40, eotaxin, granulocyte-colony stimulating factor (G-CSF), interferon-γ, monocyte chemoattractant protein-1, macrophage inflammatory protein-1β were increased, and in mice with PB, IL-1α, IL-6, G-CSF, and monokine induced by gamma-interferon showed elevated levels. Conclusions: Serum levels of cytokines in mice with HF vary depending on the etiology. Increased serum levels of several cytokines were found in models with increased right ventricular afterload, suggesting that the cytokine responses result primarily from systemic congestion.

TNF-alpha inhibition attenuates adverse myocardial remodeling in a rat model of volume overload

Tumor necrosis factor (TNF)-alpha is a proinflammatory cytokine that has been implicated in the pathogenesis of heart failure. In contrast, we have recently shown that myocardial levels of TNF-alpha are acutely elevated in the aortocaval (AV) fistula model of heart failure. Based on these observations, we hypothesized that progression of adverse myocardial remodeling secondary to volume overload would be prevented by inhibition of TNF-alpha with etanercept. Furthermore, a principal objective of this study was to elucidate the effect of TNF-alpha inhibition during different phases of the myocardial remodeling process. Eight-week-old male Sprague-Dawley rats were randomly divided into the following three groups: sham-operated controls, untreated AV fistulas, and etanercept-treated AV fistulas. Each group was further subdivided to study three different time points consisting of 3 days, 3 wk, and 8 wk postfistula. Etanercept was administered subcutaneously at 1 mg/kg body wt. Etanercept prevented collagen degradation at 3 days and significantly attenuated the decrease in collagen at 8 wk postfistula. Although TNF-alpha antagonism did not prevent the initial ventricular dilatation at 3 wk postfistula, etanercept was effective at significantly attenuating the subsequent ventricular hypertrophy, dilatation, and increased compliance at 8 wk postfistula. These positive adaptations achieved with etanercept administration translated into significant functional improvements. At a cellular level, etanercept also markedly attenuated increases in cardiomyocyte length, width, and area at 8 wk postfistula. These observations demonstrate that TNF-alpha has a pivotal role in adverse myocardial remodeling and that treatment with etanercept can attenuate the progression to heart failure.

Inhibition of Na+/H+-exchanger with sabiporide attenuates the downregulation and uncoupling of the myocardial beta-adrenoceptor system in failing rabbit hearts

Chronic heart failure (HF) is characterized by left ventricular (LV) structural remodeling, impaired function, increased circulating noradrenaline (NA) levels and impaired responsiveness of the myocardial beta-adrenoceptor (betaAR)-adenylyl cyclase (AC) system. In failing hearts, inhibition of the sodium/proton-exchanger (NHE)-1 attenuates LV remodeling and improves LV function. The mechanism(s) involved in these cardioprotective effects remain(s) unclear, but might involve effects on the impaired betaAR-AC system. Therefore, we investigated whether NHE-1 inhibition with sabiporide (SABI; 30 mg kg(-1) day(-1) p.o.) might affect myocardial betaAR density and AC activity in relation to changes in LV end-diastolic diameter (LVEDD) and LV systolic fractional shortening (LVS-FS) after 3 weeks of rapid LV pacing in rabbits. After 3 weeks of rapid LV pacing LVEDD was significantly increased (Shams 17+/-0.2 mm, n=9 vs 3 wksHF 20+/-0.5 mm, n=8; P<0.05) and LVS-FS decreased (Shams 31+/-1%, n=9 vs 3 wksHF 10+/-1%, n=8; P<0.05). SABI treatment significantly improved LV function independent of whether rabbits were treated after 1 week of pacing (3 wksHF+2 wksSABI (n=7): LVEDD 18+/-1 mm; LVS-FS 16+/-4%) or before pacing (3 wksHF+3wksSABI (n=9): LVEDD 18+/-1 mm; LVS-FS 18+/-6%). After 3 weeks of rapid LV pacing, SABI treatment significantly attenuated increases in serum NA content (Shams 0.83+/-0.19, 3 wksHF 2.68+/-0.38, 3 wksHF+2 wksSABI 1.22+/-0.32, 3 wksHF+3wksSABI 1.38+/-0.33 ng ml(-1)). Moreover, betaAR density (Shams 64+/-5, 3 wksHF 38+/-3, 3 wksHF+2 wksSABI 48+/-4, 3 wksHF+3 wksSABI 55+/-3 fmol mg(-1) protein) and responsiveness (isoprenaline-stimulated AC activity. (Shams 57.6+/-4.9, 3 wksHF 36.3+/-6.0, 3 wksHF+2 wksSABI 56.9+/-6.0, 3 wksHF+3 wksSABI 54.5+/-4.8 pmol cyclic AMP mg(-1) protein(-1) min(-1)) were significantly improved in SABI-treated rabbits. From the present data we cannot address whether the improved betaAR-AC system permitted improved LV function and/or whether the improved LV function resulted in less activation of the sympathetic nervous system and by this in a reduced stimulation of the betaAR-AC system. Accordingly, additional studies are needed to fully establish the cause-and-effect relationship between NHE-1 inhibition and the restoration of the myocardial betaAR system.

Systemic inflammation in heart failure--the whys and wherefores

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

Circulating levels of tumor necrosis factor-α correlate positively with severity of peripheral oedema in patients with right heart failure

BACKGROUND

Several previous studies have shown that circulating levels of tumor necrosis factor-alpha (TNF) are elevated in patients with advanced congestive heart failure. However, the relationship between circulating levels of TNF and severity of peripheral oedema in these patients has not been previously evaluated.

AIMS

To investigate the relationship between circulating levels of TNF, and severity of peripheral oedema in patients with right-sided heart failure (RHF).

METHODS AND RESULTS

Circulating levels of TNF were measured in 15 healthy volunteers, and in 83 patients with RHF with various levels of peripheral oedema. At presentation, 13 patients had no peripheral oedema (grade 0), 22 patients had mild peripheral oedema (grade 1), 23 patients had moderate peripheral oedema (grade 2), and 25 patients had severe peripheral oedema (grade 3). The values of circulating TNF levels (mean +/- S.E.M.) at presentation in the control group and in the RHF patients (oedema grades 0-3) were 2.98+/-0.21, 4.22+/-0.55, 4.67+/-0.29, 7.66+/-0.44, and 10.94+/-0.67 pg/mL respectively. There was a significant difference between the groups (p < 0.0001, ANOVA), and a significant positive correlation was found between circulating TNF levels and severity of peripheral oedema (r = 0.77, p<0.0001).

CONCLUSION

A significant relationship is present between circulating levels of TNF and severity of peripheral oedema in patients with RHF.

Regional differences of myocardial infarct development and ischemic preconditioning

The spatial and temporal development of myocardial infarction depends on the area at risk (AAR), the severity and duration of blood flow reduction (energy supply) as well as on heart rate and regional wall function (energy demand). Both supply and demand can vary within the AAR of a given heart, potentially resulting in differences in infarct development. We therefore retrospectively analyzed infarct size (IS, %AAR, TTC) in 24 anesthetized pigs in vivo following 90 min hypoperfusion and 120 min reperfusion of the LAD coronary artery, which supplies parts of the LV septum (LVS) and anterior free wall (LVAFW). The total LAD perfusion territory averaged 49.8 +/- 14.2 (SD) g (49.2 +/- 8.4% of LV); 61.4 +/- 8.1% of the AAR was LVAFW. IS within the LVS was 25.3 +/- 15.1%, while IS within the LVAFW was 16.6 +/-10.1% (p<0.05). While ischemic blood flow (radiolabeled microspheres) did not differ between LVS (0.05 +/- 0.02 ml/min/g) and LVAFW (0.05 +/- 0.03 ml/min/g), perivascular connective tissue (56 +/- 9 vs. 38+/-7 microm(2), p < 0.05) and the capillary-to-myocyte distance (1.65 +/- 0.23 vs. 1.18 +/- 0.23 mm, p < 0.05) were larger in LVS than in LVAFW. Interestingly, IS in LVS (9.3 +/- 9.6%, n = 24) and LVAFW (9.2 +/- 9.1%) were reduced to the same absolute extent by ischemic preconditioning with one cycle of 10 min ischemia and 15 min reperfusion, suggesting that a similar regional difference exists also in the protection afforded by ischemic preconditioning. The mechanism(s) for that remain(s) to be established.

CONCLUSION

In pigs, regional differences in infarct development and protection from it exist in the LAD perfusion territory, which are independent of ischemic blood flow but apparently related to pre-existing structural differences.