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

Scientific hypothesis and rational pharmacological for the use of sacubitril/valsartan in cardiac damage caused by COVID-19

On March 11, 2020 the World Health Organization (WHO) declared the state of global pandemic caused by the new SARS-CoV-2 (COVID-19). To date, no antivirals directed against SARS-CoV-2 or effective vaccines to combat the viral infection are available. Severe acute respiratory syndrome caused by SARS-CoV-2 is treated empirically with antivirals, anti-inflammatory, anticoagulants. The approval of an effective vaccine still takes time. In this state, it may be useful to find new therapeutic solutions from drugs already on the market. Recent hypotheses suggest that the use of AT-1 receptor antagonists (ARB) in combination with neprilisin inhibitors (NEPi) could indirectly provide clinical benefits to patients with SARS-CoV-2 and cardiac involvement. In this article we investigate and describe a possible innovative pharmacological approach for the treatment of the most severe stages of COVID-19 infection.

Usefulness of Biomarkers for Predicting Response to Cardiac Resynchronization Therapy

Cardiac Resynchronization Therapy (CRT) is an effective treatment strategy for heart failure. It significantly improves clinical symptoms and decreases mortality and long-term morbidity. However, some patients do not respond properly to this treatment. In this review, the role of different biomarkers in predicting response to CRT is discussed. Some biomarkers, including natriuretic peptides and inflammatory markers have promising results but further trials are needed for more evaluation.

A comparative study of changes of autophagy in rat models of CLP versus LPS induced sepsis

In the present study, two different rat models of sepsis, cecal ligation and puncture (CLP), and lipopolysaccharide (LPS), were established. Changes in autophagy in both models were compared using transmission electron microscopy (TEM), immunohistochemistry, western blotting, and quantitative polymerase chain reaction techniques. Consequently, TEM analysis revealed autophagic bodies in the CLP and LPS sepsis models. In addition, autophagy-related protein LC3 A-specific staining was detected in the cytoplasm. However, analysis of protein and gene expression levels revealed a statistically significant increase in autophagic activity 12 and 24 h following induction of the CLP group, and 2 h following induction of the LPS group. Thus, it was concluded that both models of sepsis exhibited increased autophagic activity of the cardiomyocytes over time. The LPS model was superior to the CLP model in perturbation of molecular biological mechanisms, while the latter would be more likely suited for the study of physiological functions.

Severity of chronic experimental Chagas' heart disease parallels tumour necrosis factor and nitric oxide levels in the serum: models of mild and severe disease

Heart tissue inflammation, progressive fibrosis and electrocardiographic alterations occur in approximately 30% of patients infected by Trypanosoma cruzi, 10-30 years after infection. Further, plasma levels of tumour necrosis factor (TNF) and nitric oxide (NO) are associated with the degree of heart dysfunction in chronic chagasic cardiomyopathy (CCC). Thus, our aim was to establish experimental models that mimic a range of parasitological, pathological and cardiac alterations described in patients with chronic Chagas’ heart disease and evaluate whether heart disease severity was associated with increased TNF and NO levels in the serum. Our results show that C3H/He mice chronically infected with the Colombian T. cruzi strain have more severe cardiac parasitism and inflammation than C57BL/6 mice. In addition, connexin 43 disorganisation and fibronectin deposition in the heart tissue, increased levels of creatine kinase cardiac MB isoenzyme activity in the serum and more severe electrical abnormalities were observed in T. cruzi-infected C3H/He mice compared to C57BL/6 mice. Therefore, T. cruzi-infected C3H/He and C57BL/6 mice represent severe and mild models of CCC, respectively. Moreover, the CCC severity paralleled the TNF and NO levels in the serum. Therefore, these models are appropriate for studying the pathophysiology and biomarkers of CCC progression, as well as for testing therapeutic agents for patients with Chagas’ heart disease.

The Importance of NLRP3 Inflammasome in Heart Failure

Patients with heart failure continue to suffer adverse health consequences despite advances in therapies over the past 2 decades. Identification of novel therapeutic targets that may attenuate disease progression is therefore needed. The inflammasome may play a central role in modulating chronic inflammation and in turn affecting heart failure progression. The inflammasome is a complex of intracellular interaction proteins that trigger maturation of proinflammatory cytokines interleukin-1β and interleukin-18 to initiate the inflammatory response. This response is amplified through production of tumor necrosis factor α and activation of inducible nitric oxide synthase. The purpose of this review is to discuss recent evidence implicating this inflammatory pathway in the pathophysiology of heart failure.

Myocardial and anti-inflammatory effects of chronic bosentan therapy in monocrotaline-induced pulmonary hypertension

INTRODUCTION AND OBJECTIVES

Endothelin-1 antagonists are increasingly used in the treatment of pulmonary hypertension despite the lack of knowledge of their myocardial and systemic effects. We assessed the right ventricular myocardial and systemic effects of endothelin-1 antagonists in monocrotaline-induced pulmonary hypertension.

METHODS

Male Wistar rats (180-200 g, n=57) randomly received 60 mg/kg monocrotaline or vehicle subcutaneously. Two days later, bosentan was randomly started (300 mg/kg/day) by oral route in a subgroup of monocrotaline-injected rats, while the other monocrotaline-injected and control rats received vehicle. At 25-30 days, invasive hemodynamic assessment was performed under anesthesia, arterial blood samples were collected for gas analysis and plasma was extracted for quantification of endothelin-1, cytokines, nitrates and 6-keto-prostaglandin F1α. Right ventricular myocardium was collected for assessment of cyclooxygenase and nitric oxide synthase activity and gene expression.

RESULTS

The monocrotaline group developed pulmonary hypertension, low cardiac output, right ventricular hypertrophy and dilation, changes in gene expression and inflammatory activation that were attenuated in the group treated with bosentan. From a functional point of view, this group had improved right ventricular function and preserved ventriculo-vascular coupling, without deterioration in arterial gas parameters or systemic hypotension. In molecular terms, they showed reduced endothelin-1 and cytokine levels, decreased right ventricular inducible nitric oxide synthase and cyclooxygenase-2 activity and increased nitrate plasma levels compared with the non-treated group.

CONCLUSIONS

In this study we demonstrate that besides attenuating pulmonary hypertension, bosentan has beneficial hemodynamic, myocardial and anti-inflammatory effects.

Cardiac biomarkers in heart failure

BACKGROUND

Heart failure is a syndrome characterized by the inability of the heart to meet the body's circulatory demands. Heart failure is a growing health issue worldwide and the prevalence of heart failure is expected to rise as populations age. Therapies and interventions for a variety of cardiac conditions continue to advance and biomarkers will play an increasing role in patient management.

METHODS

This is a review of the clinical research in blood based biomarkers for diagnosis, prognosis and therapeutic guidance of heart failure. The focus of this review is biomarkers that are currently available for clinical measurement, and their current and potential for applications for managing heart failure patients.

RESULTS

The various biologic pathways and physiologic processes of heart failure biomarkers represent a host of different including inflammation, remodeling, strain, neurohormonal activation, metabolism and cardiac myocyte injury. The clinical characteristics and applications of each heart failure biomarker are discussed.

CONCLUSION

As populations age and effective treatments and interventions for coronary artery disease improve, heart failure will increase in incidence and prevalence. Blood biomarkers will play an increasing role in the early diagnosis, therapeutic monitoring and management of heart failure patients in the future.

Inflammatory activation: cardiac, renal, and cardio-renal interactions in patients with the cardiorenal syndrome

Although inflammation is a physiologic response designed to protect us from infection, when unchecked and ongoing it may cause substantial harm. Both chronic heart failure (CHF) and chronic kidney disease (CKD) are known to cause elaboration of several pro-inflammatory mediators that can be detected at high concentrations in the tissues and blood stream. The biologic sources driving this chronic inflammatory state in CHF and CKD are not fully established. Traditional sources of inflammation include the heart and the kidneys which produce a wide range of pro-inflammatory cytokines in response to neurohormones and sympathetic activation. However, growing evidence suggests that non-traditional biomechanical mechanisms such as venous and tissue congestion due to volume overload are also important as they stimulate endotoxin absorption from the bowel and peripheral synthesis and release of pro-inflammatory mediators. Both during the chronic phase and, more rapidly, during acute exacerbations of CHF and CKD, inflammation and congestion appear to amplify each other resulting in a downward spiral of worsening cardiac, vascular, and renal functions that may negatively impact patients' outcome. Anti-inflammatory treatment strategies aimed at attenuating end organ damage and improving clinical prognosis in the cardiorenal syndrome have been disappointing to date. A new therapeutic paradigm may be needed, which involves different anti-inflammatory strategies for individual etiologies and stages of CHF and CKD. It may also include specific (short-term) anti-inflammatory treatments that counteract inflammation during the unsettled phases of clinical decompensation. Finally, it will require greater focus on volume overload as an increasingly significant source of systemic inflammation in the cardiorenal syndrome.

Inducible nitric oxide synthase in heart tissue and nitric oxide in serum of Trypanosoma cruzi-infected rhesus monkeys: association with heart injury

Background

The factors contributing to chronic Chagas' heart disease remain unknown. High nitric oxide (NO) levels have been shown to be associated with cardiomyopathy severity in patients. Further, NO produced via inducible nitric oxide synthase (iNOS/NOS2) is proposed to play a role in Trypanosoma cruzi control. However, the participation of iNOS/NOS2 and NO in T. cruzi control and heart injury has been questioned. Here, using chronically infected rhesus monkeys and iNOS/NOS2-deficient (Nos2^−/−) mice we explored the participation of iNOS/NOS2-derived NO in heart injury in T. cruzi infection.

Methodology

Rhesus monkeys and C57BL/6 and Nos2^−/− mice were infected with the Colombian T. cruzi strain. Parasite DNA was detected by polymerase chain reaction, T. cruzi antigens and iNOS/NOS2⁺ cells were immunohistochemically detected in heart sections and NO levels in serum were determined by Griess reagent. Heart injury was assessed by electrocardiogram (ECG), echocardiogram (ECHO), creatine kinase heart isoenzyme (CK-MB) activity levels in serum and connexin 43 (Cx43) expression in the cardiac tissue.

Results

Chronically infected monkeys presented conduction abnormalities, cardiac inflammation and fibrosis, which resembled the spectrum of human chronic chagasic cardiomyopathy (CCC). Importantly, chronic myocarditis was associated with parasite persistence. Moreover, Cx43 loss and increased CK-MB activity levels were primarily correlated with iNOS/NOS2⁺ cells infiltrating the cardiac tissue and NO levels in serum. Studies in Nos2^−/− mice reinforced that the iNOS/NOS2-NO pathway plays a pivotal role in T. cruzi-elicited cardiomyocyte injury and in conduction abnormalities that were associated with Cx43 loss in the cardiac tissue.

Conclusion

T. cruzi-infected rhesus monkeys reproduce features of CCC. Moreover, our data support that in T. cruzi infection persistent parasite-triggered iNOS/NOS2 in the cardiac tissue and NO overproduction might contribute to CCC severity, mainly disturbing of the molecular pathway involved in electrical synchrony. These findings open a new avenue for therapeutic tools in Chagas' heart disease.

Chagas disease, a neglected tropical disease caused by the protozoan Trypanosoma cruzi, afflicts from 8 to 15 million people in the Latin America. Chronic chagasic cardiomyopathy (CCC) is the most frequent manifestation of Chagas disease. Currently, patient management only mitigates CCC symptoms. The pathogenic factors leading to CCC remain unknown; therefore their comprehension may contribute to develop more efficient therapies. In patients, high nitric oxide (NO) levels have been associated with CCC severity. In T. cruzi-infected mice, NO, mainly produced via inducible nitric oxide synthase (iNOS/NOS2), is proposed to work in parasite control. However, the participation of iNOS/NOS2 and NO in T. cruzi control and heart injury has been questioned. Here, infected rhesus monkeys and iNOS/NOS2-deficient mice were used to explore the participation of iNOS/NOS2-derived NO in heart injury in T. cruzi infection. Chronically infected monkeys presented electrical abnormalities, myocarditis and fibrosis, resembling the spectrum of human CCC. Moreover, cardiomyocyte lesion correlated with iNOS/NOS2⁺ cells infiltrating the cardiac tissue. Our findings support that parasite-driven iNOS/NOS2⁺ cells accumulation in the cardiac tissue and NO overproduction contribute to cardiomyopathy severity, mainly disturbing the pathway involved in electrical synchrony in T. cruzi infection.

Current concepts underlying benefits of exercise training in congestive heart failure patients

The pathophysiology of several conditions including heart failure is partly attributable to a failure of the cell energy metabolism. Studies have shown that exercise training (ET) improves quality of life (QOL) and is beneficial in terms of reduction of symptoms, mortality and duration of hospitalization. Increasingly, ET is now achieving acceptance as complimentary therapy in addition to routine clinical practice in patients with chronic heart failure (CHF). However, the mechanisms underlying the beneficial effects of ET are far less understood and need further evaluation. Evidence suggests that while CHF induces generalized metabolic energy depletion, ET largely enhances the overall function of the heart muscle. Hence, research efforts are now aiming to uncover why ET is beneficial as a complimentary treatment of CHF in the context of improving endothelial function and coronary perfusion, decreasing peripheral resistance, induction of cardiac and skeletal muscle cells remodeling, increasing oxygen uptake, substrate oxidation, and resistance to fatigue. Here we discuss the current evidence that suggest that there are beneficial effects of ET on cardiac and skeletal muscle cells oxidative metabolism and intracellular energy transfer in patients with CHF.

Proinflammatory cytokines in heart failure: double-edged swords

Increased circulating and intracardiac levels of proinflammatory cytokines have been associated with chronic heart failure. Following an initial insult, the increased production of proinflammatory cytokines, including TNF-α, IL-6, IL-1, and IL-18, jeopardizes the surrounding tissue through propagation of the inflammatory response and direct effects on the cardiac myocyte structure and function. Cardiac myocyte hypertrophy, contractile dysfunction, cardiac myocyte apoptosis, and extracellular matrix remodeling contribute enormously to the development and progression of chronic heart failure. Despite the identification of efficacious pharmacological regimens and introduction of mechanical interventions, chronic heart failure remains among the leading causes of mortality worldwide. To introduce novel therapeutic strategies that modulate the inflammatory response in the context of the failing heart, it is of prime importance to determine the contributions of TNF-α, IL-6, IL-1, and IL-18 in mediating cardiac adaptive and maladaptive responses, as well as delineating their downstream intracellular signaling pathways and their potential therapeutic implications.

Rapid nitric oxide-dependent effects of tumor necrosis factor-alpha on suprachiasmatic nuclei neuronal activity

The effect of tumor necrosis factor-alpha (TNF-alpha) on excitability and synaptic function was analyzed in slice preparations of the suprachiasmatic nuclei (SCN), the major mammalian circadian pacemaker. TNF-alpha caused a rapid increase in the spontaneous firing rate in most SCN neurons examined that was paralleled by an increase of inhibitory postsynaptic currents. The nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester abolished these effects. No effect of TNF-alpha was found on miniature synaptic currents. The lack of effect on miniature synaptic currents indicates that TNF-alpha primarily affects neuronal membrane properties to cause the changes in spontaneous firing. TNF-alpha, levels of which show circadian variation in the brain and increase during inflammatory conditions and aging, may thus through nitric oxide induction modulate SCN electrical output to affect downstream circadian rhythms.

Role of inflammation in atherosclerosis associated with rheumatoid arthritis

Rheumatoid arthritis (RA) is associated with excess morbidity and mortality from myocardial infarction and allied disorders. A large body of evidence supports the involvement of common proinflammatory cytokines in the development and progression of both RA and atherosclerosis. The destructive proinflammatory cascade and effector mechanisms implicated in RA resemble the chronic inflammatory processes that drive the development of atherosclerosis in general. Proinflammatory cytokines such as interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha produced within locally affected joints in RA may promote both traditional (e.g., dyslipidemia, insulin resistance) and nontraditional (e.g., oxidative stress) systemic cardiovascular risk factors. Expression of proinflammatory cytokines and inflammatory mediators influences all stages of atherosclerosis development, from early atheroma formation to thrombus development responsible for events such as myocardial infarction. Appreciation of the inflammatory process shared by RA and atherosclerosis should heighten the recognition of this morbid association and lead to better recognition and management of cardiovascular risk in patients with rheumatologic diseases.

Biologics and heart failure in rheumatoid arthritis: are we any wiser?

PURPOSE OF REVIEW

To summarize the recent literature concerning the role of TNF-alpha in heart failure, epidemiology of heart failure in rheumatoid arthritis and risk of heart failure associated with biologic disease-modifying antirheumatic drugs in rheumatoid arthritis.

RECENT FINDINGS

TNF-alpha has been implicated in the pathogenesis of heart failure. It has direct deleterious effects on the myocardium in the setting of acute injury or chronic heart failure. In animal models, TNF-alpha is important in cardiac remodeling, leading to cardiac dysfunction following acute injury. Both incident and worsening heart failure have been reported in patients with rheumatoid arthritis who are treated with anti-TNF-alpha therapy. Recent cohort studies, however, have shown no increased risk and, in some, a protective effect on the risk of heart failure. Certain traditional cardiovascular risk factors have a relatively lesser contribution to cardiovascular morbidity and mortality in patients with rheumatoid arthritis, suggesting that disease-related perturbations of the cytokine network may contribute to the excess risk of heart failure in these patients.

SUMMARY

Overall mortality in rheumatoid arthritis has remained stagnant despite advances in rheumatoid arthritis and heart failure management and improved cardiovascular mortality in the general population. Heart failure prevalence is increased in patients with rheumatoid arthritis and leads to greater mortality. Despite current expert consensus contraindicating the use of anti-TNF-alpha agents in patients with moderate to severe heart failure, epidemiological studies in rheumatoid arthritis have not consistently substantiated this association.

Research progress in the mechanism of renal vasoconstriction in hepatorenal syndrome

Hepatorenal syndrome (HRS) is defined as the development of renal failure in patients with severe liver disease in the absence of any other identifiable cause of renal pathology. The hallmark of HRS is renal vasoconstriction. The cause of renal vasoconstriction may involve several factors: activation of renal nervous system, imbalance of renal vasoactive mediators and molecular mechanism. In this review, we summarize the above progress.

Sodium nitroprusside activates p38 mitogen activated protein kinase through a cGMP/PKG independent mechanism

The objective of this study was to understand the mechanism of action of nitric oxide (NO) in the heart by determining whether nitric oxide (NO) released from sodium nitroprusside (SNP) induces p38 mitogen activated protein kinase (p38 MAPK) phosphorylation and whether this is mediated through a cyclic GMP (cGMP)/protein kinase G (PKG) pathway. p38 MAPK activation was examined by Western blotting of whole cell lysates of embryonic chick cardiomyocytes with antibodies specific to the native or phosphorylated forms of p38 MAPK. SNP, 1 mM, which released significant amounts of NO as determined by Griess reaction, induced p38 MAPK phosphorylation that was apparent within 10 min, was significantly (p<0.05) greater than control at 60 min and remained higher than initial levels up to the 4 h end point of the experiment. This could not be attributed to hydrogen peroxide release from SNP as catalase did not affect SNP-induced p38 MAPK phosphorylation. SB202190, a relatively selective inhibitor of p38 MAPK, mainly p38alpha MAPK, inhibited SNP-induced p38 MAPK phosphorylation. SNP-induced p38 MAPK phosphorylation was not altered by pre-treatment with the PKG inhibitor KT 5823 or by ODQ a potent and selective inhibitor of NO-sensitive guanylyl cyclase. p38 MAPK phosphorylation was not induced by the cell permeable cGMP analogue, 8-Br-cGMP. In summary, considering that new therapeutic strategies aimed at NO and p38 MAPK are being considered for myocardial injury and heart failure, these data demonstrate that SNP induces p38 MAPK phosphorylation through a pathway that is independent of NO-induced activation of cGMP/PKG pathways and suggest that non cGMP/PKG regulatory proteins leading to p38 MAPK phosphorylation merit further investigation to address this therapeutic target.