Myocardial inflammation in experimental acute right ventricular failure: Effects of prostacyclin therapy

The neutrophil-to-apolipoprotein A1 ratio is associated with adverse outcomes in patients with acute decompensated heart failure at different glucose metabolic states: a retrospective cohort study

BACKGROUND

The present study was performed to assess the association between the neutrophil-to-apolipoprotein A1 ratio (NAR) and outcomes in patients with acute decompensated heart failure (ADHF) at different glucose metabolism states.

METHODS

We recruited 1233 patients with ADHF who were admitted to Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University from December 2014 to October 2019. The endpoints were defined as composites of cardiovascular death, nonfatal myocardial infarction, nonfatal ischemic stroke and exacerbation of chronic heart failure. The restricted cubic spline was used to determine the best cutoff of NAR, and patients were divided into low and high NAR groups. Kaplan-Meier plots and multivariable Cox proportional hazard models were used to investigate the association between NAR and the risk of adverse outcomes.

RESULTS

During the five-year follow-up period, the composite outcome occurred in 692 participants (56.1%). After adjusting for potential confounding factors, a higher NAR was associated with a higher incidence of composite outcomes in the total cohort (Model 1: HR = 1.42, 95% CI = 1.22-1.65, P<0.001; Model 2: HR = 1.29, 95% CI = 1.10-1.51, P = 0.002; Model 3: HR = 1.20, 95% CI = 1.01-1.42, P = 0.036). At different glucose metabolic states, a high NAR was associated with a high risk of composite outcomes in patients with diabetes mellitus (DM) (Model 1: HR = 1.54, 95% CI = 1.25-1.90, P<0.001; Model 2: HR = 1.40, 95% CI = 1.13-1.74, P = 0.002; Model 3: HR = 1.31, 95% CI = 1.04-1.66, P = 0.022), and the above association was not found in patients with prediabetes mellitus (Pre-DM) or normal glucose regulation (NGR) (both P>0.05).

CONCLUSIONS

The NAR has predictive value for adverse outcomes of ADHF with DM, which implies that the NAR could be a potential indicator for the management of ADHF.

Classification and Predictors of Right Ventricular Functional Recovery in Pulmonary Arterial Hypertension

BACKGROUND

Normative changes in right ventricular (RV) structure and function have not been characterized in the context of treatment-associated functional recovery (RV functional recovery [RVFnRec]). The aim of this study is to assess the clinical relevance of a proposed RVFnRec definition.

METHODS

We evaluated 63 incident patients with pulmonary arterial hypertension by right heart catheterization and cardiac magnetic resonance imaging at diagnosis and cardiac magnetic resonance imaging and invasive cardiopulmonary exercise testing following treatment (≈11 months). Sex, age, ethnicity matched healthy control subjects (n=62) with 1-time cardiac magnetic resonance imaging and noninvasive cardiopulmonary exercise testing were recruited from the PVDOMICS (Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics) project. We examined therapeutic cardiac magnetic resonance imaging changes relative to the evidence-based peak oxygen consumption (VO2peak)>15 mL/(kg·min) to define RVFnRec by receiver operating curve analysis. Afterload was measured as mean pulmonary artery pressure, resistance, compliance, and elastance.

RESULTS

A drop in RV end-diastolic volume of -15 mL best defined RVFnRec (area under the curve, 0.87; P=0.0001) and neared upper 95% CI RV end-diastolic volume of controls. This cutoff was met by 22 out of 63 (35%) patients which was reinforced by freedom from clinical worsening, RVFnRec 1 out of 21 (5%) versus no RVFnRec 17 out of 42, 40% (log-rank P=0.006). A therapy-associated increase of 0.8 mL/mm Hg in compliance had the best predictive value of RVFnRec (area under the curve, 0.76; [95% CI, 0.64-0.88]; P=0.001). RVFnRec patients had greater increases in stroke volume, and cardiac output at exercise.

CONCLUSIONS

RVFnRec defined by RV end-diastolic volume therapeutic decrease of -15 mL predicts exercise capacity, freedom from clinical worsening, and nears normalization. A therapeutic improvement of compliance is superior to other measures of afterload in predicting RVFnRec. RVFnRec is also associated with increased RV output reserve at exercise.

Pathophysiology of the right ventricle in health and disease: an update

The contribution of the right ventricle (RV) to cardiac output is negligible in normal resting conditions when pressures in the pulmonary circulation are low. However, the RV becomes relevant in healthy subjects during exercise and definitely so in patients with increased pulmonary artery pressures both at rest and during exercise. The adaptation of RV function to loading rests basically on an increased contractility. This is assessed by RV end-systolic elastance (Ees) to match afterload assessed by arterial elastance (Ea). The system has reserve as the Ees/Ea ratio or its imaging surrogate ejection fraction has to decrease by more than half, before the RV undergoes an increase in dimensions with eventual increase in filling pressures and systemic congestion. RV-arterial uncoupling is accompanied by an increase in diastolic elastance. Measurements of RV systolic function but also of diastolic function predict outcome in any cause pulmonary hypertension and heart failure with or without preserved left ventricular ejection fraction. Pathobiological changes in the overloaded RV include a combination of myocardial fibre hypertrophy, fibrosis and capillary rarefaction, a titin phosphorylation-related displacement of myofibril tension-length relationships to higher pressures, a metabolic shift from mitochondrial free fatty acid oxidation to cytoplasmic glycolysis, toxic lipid accumulation, and activation of apoptotic and inflammatory signalling pathways. Treatment of RV failure rests on the relief of excessive loading.

Right Ventricular Subclinical Dysfunction in SLE Patients Correlates with Metabolomic Fingerprint and Organ Damage

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease, and several studies have suggested possible early RV involvement. Aim of the study was to evaluate the 3D echo parameters of the right ventricle (RV) and the metabolomic profile to correlate both with SLE severity. Forty SLE patients, free of cardiovascular disease, were enrolled and the following 3D parameters were evaluated: the RV ejection fraction (RV-EF), longitudinal strain of the interventricular septum (Septal LS), longitudinal strain of the free wall (Free-LS) and the fractional area change (FAC). In addition, a metabolomic analysis was performed. Direct correlations were observed between TAPSE values and the RV 3D parameters. Then, when splitting the population according to the SDI value, it was found that patients with higher cumulative damage (≥3) had significantly lower FAC, RV-EF, Septal LS, and Free-LS values; the latter three parameters showed a significant correlation with the metabolic profile of the patients. Furthermore, the division based on SDI values identified different metabolic profiles related to the degree of RV dysfunction. The RV dysfunction induced by the chronic inflammatory state present in SLE can be identified early by 3D echocardiography. Its severity seems to be related to systemic organ damage and the results associated with a specific metabolic fingerprint constituted by 2,4-dihydroxybutyric acid, 3,4-dihydroxybutyric acid, citric acid, glucose, glutamine, glycine, linoleic acid, oleic acid, phosphate, urea, and valine.

Beneficial Effects of Tacrolimus on Brain-Death-Associated Right Ventricular Dysfunction in Pigs

BACKGROUND

Right ventricular (RV) dysfunction remains a major problem after heart transplantation and may be associated with brain death (BD) in a donor. A calcineurin inhibitor tacrolimus was recently found to have beneficial effects on heart function. Here, we examined whether tacrolimus might prevent BD-induced RV dysfunction and the associated pathobiological changes.

METHODS

After randomized tacrolimus (n = 8; 0.05 mg·kg-1·day-1) or placebo (n = 9) pretreatment, pigs were assigned to a BD procedure and hemodynamically investigated 1, 3, 5, and 7 h after the Cushing reflex. After euthanasia, myocardial tissue was sampled for pathobiological evaluation. Seven pigs were used as controls.

RESULTS

Calcineurin inhibition prevented increases in pulmonary vascular resistance and RV-arterial decoupling induced by BD. BD was associated with an increased RV pro-apoptotic Bax-to-Bcl2 ratio and RV and LV apoptotic rates, which were prevented by tacrolimus. BD induced increased expression of the pro-inflammatory IL-6-to-IL-10 ratio, their related receptors, and vascular cell adhesion molecule-1 in both the RV and LV. These changes were prevented by tacrolimus. RV and LV neutrophil infiltration induced by BD was partly prevented by tacrolimus. BD was associated with decreased RV expression of the β-1 adrenergic receptor and sarcomere (myosin heavy chain [MYH]7-to-MYH6 ratio) components, while β-3 adrenergic receptor, nitric oxide-synthase 3, and glucose transporter 1 expression increased. These changes were prevented by tacrolimus.

CONCLUSIONS

Brain death was associated with isolated RV dysfunction. Tacrolimus prevented RV dysfunction induced by BD through the inhibition of apoptosis and inflammation activation.

Classification and Predictors of Right Ventricular Functional Recovery in Pulmonary Arterial Hypertension

Background

Normative changes in right ventricular (RV) structure and function have not been characterized in the context of treatment-associated functional recovery (RVFnRec). The aim of this study is to assess the clinical relevance of a proposed RVFnRec definition.

Methods

We evaluated 63 incident patients with PAH by right heart catheterization and cardiac MRI (CMR) at diagnosis and CMR and invasive cardiopulmonary exercise (CPET) following treatment (∼11 months). Sex, age, race/ethnicity matched healthy control subjects (n=62) with one-time CMR and non-invasive CPET were recruited from the PVDOMICS project. We examined therapeutic CMR changes relative to the evidence-based peak oxygen consumption (VO2 peak )>15mL/kg/min to define RVFnRec by receiver operating curve analysis. Afterload was measured in the as mean pulmonary artery pressure, resistance, compliance, and elastance.

Results

A drop in RV end-diastolic volume of -15 mL best defined RVFnRec (AUC 0.87, P=0.0001) and neared upper 95% CI RVEDV of controls. 22/63 (35%) of subjects met this cutoff which was reinforced by freedom from clinical worsening, RVFnRec 1/21 (5%) versus no RVFnRec 17/42, 40%, (log rank P=0.006). A therapy-associated increase of 0.8 mL/mmHg in compliance had the best predictive value of RVFnRec (AUC 0.76, CI 0.64-0.88, P=0.001). RVFnRec subjects had greater increases in stroke volume, and cardiac output at exercise.

Conclusions

RVFnRec defined by RVEDV therapeutic decrease of -15mL predicts exercise capacity, freedom from clinical worsening, and nears normalization. A therapeutic improvement of compliance is superior to other measures of afterload in predicting RVFnRec. RVFnRec is also associated with increased RV output reserve at exercise.

Clinical Perspective

What is new?: Right ventricular functional recovery (RVFnRec) represents a novel endpoint of therapeutic success in PAH. We define RVFnRec as treatment associated normative RV changes related to function (peak oxygen consumption). Normative RV imaging changes are compared to a well phenotyped age, sex, and race/ethnicity matched healthy control cohort from the PVDOMICS project. Previous studies have focused on RV ejection fraction improvements. However, we show that changes in RVEDV are perhaps more important in that improvements in LV function also occur. Lastly, RVFnRec is best predicted by improvements in pulmonary artery compliance versus pulmonary vascular resistance, a more often cited metric of RV afterload.What are the clinical implications?: RVFnRec represents a potential non-invasive assessment of clinical improvement and therapeutic response. Clinicians with access to cardiac MRI can obtain a limited scan (i.e., ventricular volumes) before and after treatment. Future study should examine echocardiographic correlates of RVFnRec.

A Comprehensive Assessment of Right Ventricular Function in Chronic Thromboembolic Pulmonary Hypertension

While chronic thromboembolic pulmonary hypertension (CTEPH) results from macroscopic and microscopic obstruction of the pulmonary vascular bed, the function of the right ventricle (RV) and increased RV afterload are the main determinants of its symptoms and prognosis. In this review, we assess RV function in patients diagnosed with CTEPH with a focus on the contributions of RV afterload and dysfunction to the pathogenesis of this disease. We will also discuss changes in RV function and geometry in response to treatment, including medical therapy, pulmonary endarterectomy, and balloon pulmonary angioplasty.

Cardiac Fibrosis in the Pressure Overloaded Left and Right Ventricle as a Therapeutic Target

Myocardial fibrosis is a remodeling process of the extracellular matrix (ECM) following cardiac stress. "Replacement fibrosis" is a term used to describe wound healing in the acute phase of an injury, such as myocardial infarction. In striking contrast, ECM remodeling following chronic pressure overload insidiously develops over time as "reactive fibrosis" leading to diffuse interstitial and perivascular collagen deposition that continuously perturbs the function of the left (L) or the right ventricle (RV). Examples for pressure-overload conditions resulting in reactive fibrosis in the LV are systemic hypertension or aortic stenosis, whereas pulmonary arterial hypertension (PAH) or congenital heart disease with right sided obstructive lesions such as pulmonary stenosis result in RV reactive fibrosis. In-depth phenotyping of cardiac fibrosis has made it increasingly clear that both forms, replacement and reactive fibrosis co-exist in various etiologies of heart failure. While the role of fibrosis in the pathogenesis of RV heart failure needs further assessment, reactive fibrosis in the LV is a pathological hallmark of adverse cardiac remodeling that is correlated with or potentially might even drive both development and progression of heart failure (HF). Further, LV reactive fibrosis predicts adverse outcome in various myocardial diseases and contributes to arrhythmias. The ability to effectively block pathological ECM remodeling of the LV is therefore an important medical need. At a cellular level, the cardiac fibroblast takes center stage in reactive fibrotic remodeling of the heart. Activation and proliferation of endogenous fibroblast populations are the major source of synthesis, secretion, and deposition of collagens in response to a variety of stimuli. Enzymes residing in the ECM are responsible for collagen maturation and cross-linking. Highly cross-linked type I collagen stiffens the ventricles and predominates over more elastic type III collagen in pressure-overloaded conditions. Research has attempted to identify pro-fibrotic drivers causing fibrotic remodeling. Single key factors such as Transforming Growth Factor β (TGFβ) have been described and subsequently targeted to test their usefulness in inhibiting fibrosis in cultured fibroblasts of the ventricles, and in animal models of cardiac fibrosis. More recently, modulation of phenotypic behaviors like inhibition of proliferating fibroblasts has emerged as a strategy to reduce pathogenic cardiac fibroblast numbers in the heart. Some studies targeting LV reactive fibrosis as outlined above have successfully led to improvements of cardiac structure and function in relevant animal models. For the RV, fibrosis research is needed to better understand the evolution and roles of fibrosis in RV failure. RV fibrosis is seen as an integral part of RV remodeling and presents at varying degrees in patients with PAH and animal models replicating the disease of RV afterload. The extent to which ECM remodeling impacts RV function and thus patient survival is less clear. In this review, we describe differences as well as common characteristics and key players in ECM remodeling of the LV vs. the RV in response to pressure overload. We review pre-clinical studies assessing the effect of anti-fibrotic drug candidates on LV and RV function and their premise for clinical testing. Finally, we discuss the mode of action, safety and efficacy of anti-fibrotic drugs currently tested for the treatment of left HF in clinical trials, which might guide development of new approaches to target right heart failure. We touch upon important considerations and knowledge gaps to be addressed for future clinical testing of anti-fibrotic cardiac therapies.

Pericardial effusion after congenital heart surgery

Objective

Pericardial effusion after cardiac surgery remains an important cause of morbidity and mortality. We describe the risk factors of pericardial effusion after congenital heart surgery through analyzing data from a nationwide, multi-institutional registry.

Methods

The Japan Congenital Cardiovascular Surgery Database, which reflects routine clinical care in Japan, was used for this retrospective cohort study. Multivariable regression analysis was done after univariable comparison of patients with pericardial effusion and no pericardial effusion.

Results

The study enrolled 64,777 patients registered with the Japan Congenital Cardiovascular Surgery Database between 2008 and 2016; 909 of these had postoperative pericardial effusion (1.4%) and were analyzed along with 63,868 patients without pericardial effusion. Univariable analysis found no difference between the groups in terms of gender, early delivery, or preoperative mechanical ventilatory support. In the pericardial effusion group, cardiopulmonary bypass use was lower (58.4% vs 62.1%), whereas the cardiopulmonary bypass time (176.9 vs 139.9 minutes) and aortic crossclamp time (75.1 vs 62.2 minutes) were longer, and 30-day mortality was higher (4.1% vs 2.2%). Multivariable analysis identified trisomy 21 (odds ratio, 1.54), 22q.11 deletion (odds ratio, 2.17), first-time cardiac surgery (odds ratio, 2.01), and blood transfusion (odds ratio, 1.43) as independent risk factors of postoperative pericardial effusion. In contrast, neonates, infants, ventricular septal defect, atrial septal defect, tetralogy of Fallot repair, and arterial switch operation were correlated with a low risk of pericardial effusion development.

Conclusions

The incidence of postoperative pericardial effusion in congenital cardiac surgery was 1.4%. Trisomy 21, 22q.11 deletion, first-time cardiac surgery, and blood transfusion were identified as the principal factors predicting the need for pericardial effusion drainage.

Sulforaphane Does Not Protect Right Ventricular Systolic and Diastolic Functions in Nrf2 Knockout Pulmonary Artery Hypertension Mice

PURPOSE

Nrf2 is a nuclear transcription factor and plays an important role in the regulation of oxidative stress and inflammation. We recently demonstrated that sulforaphane (SFN) protected mice from developing pulmonary arterial hypertension (PAH) and right ventricular (RV) dysfunction by elevating cardiac Nrf2 expression and function. Here we further investigate Nrf2 dependence for SFN-mediated prevention of PAH and RV dysfunction in an Nrf2 knockout mouse model.

METHODS

We used male global Nrf2-knockout mice and male C57/6 J wild type mice in the following groups: Control group received room air and vehicle control; SuHx group received SU5416 and 10% hypoxia for 4 weeks to induce PAH; SuHx+SFN group received both SuHx and sulforaphane, a Nrf2 activator, for 4 weeks. Transthoracic echocardiography was performed to quantify RV function and estimate pulmonary vascular resistance over 4 weeks. PAH was confirmed using invasive RV systolic pressure measurement at 4 weeks.

RESULTS

All Nrf2 knockout mice survived the 4-week SuHx induction of PAH. SuHx caused progressive RV diastolic/systolic dysfunction and increased RV systolic pressure. The development of RV diastolic dysfunction occurred earlier in the Nrf2 knockout PAH mice when compared with the wide type PAH mice. SFN partially or completely reversed SuHx-induced RV diastolic/systolic dysfunction and increased RV systolic pressure in wild-type mice, but not in Nrf2 knockout mice.

CONCLUSION

Our findings demonstrated the essential role of Nrf2 in SFN-mediated prevention of RV dysfunction and PAH, and increasing Nrf2 activity in patients with PAH may have therapeutic potential.

Altered mRNA Expression of Interleukin-1 Receptors in Myocardial Tissue of Patients with Left Ventricular Assist Device Support

Serum levels of cytokines interleukin 1 beta ( IL-1β) and interleukin 33 (IL-33) are highly abnormal in heart failure and remain elevated after mechanical circulatory support (MCS). However, local cytokine signaling induction remains elusive. Left (LV) and right ventricular (RV) myocardial tissue specimens of end-stage heart failure (HF) patients without (n = 24) and with MCS (n = 39; 594 ± 57 days) were analyzed for cytokine mRNA expression level of IL-1B, interleukin 1 receptor 1/2 (IL-1R1/2), interleukin 1 receptor-like 1 (IL-1RL1), IL-33 and interleukin-1 receptor accessory protein (IL-1RaP). MCS patients showed significantly elevated IL-1B expression levels (LV: 2.0 fold, p = 0.0058; RV: 3.3 fold, p < 0.0001). Moreover, IL-1R1, IL-1RaP and IL-33 expression levels strongly correlated with each other. IL-1RL1 and IL-1R2 expression levels were significantly higher in RV myocardial tissue (RV/LV ratio IL-1R2 HF: 4.400 ± 1.359; MCS: 4.657 ± 0.655; IL-1RL1 HF: 3.697 ± 0.876; MCS: 4.529 ± 0.5839). In addition, IL1-RaP and IL-33 RV expression levels were significantly elevated in MCS. Furthermore, IL-33 expression correlates with C-reactive protein (CRP) plasma levels in HF, but not in MCS patients. Increased expression of IL-1B and altered correlation patterns of IL-1 receptors indicate enhanced IL-1β signaling in MCS patients. Correlation of IL-1 receptor expression with IL-33 may hint towards a link between both pathways. Moreover, diverging expression in LV and RV suggests specific regulation of local cytokine signaling.

Epoprostenol up-regulates serum adiponectin level in patients with systemic sclerosis: therapeutic implications

INTRODUCTION

Adiponectin, resistin and leptin belong to adipokines, a group of molecules secreted mainly by the adipose tissue, which impaired expression may be a missing link between various manifestations of systemic sclerosis. Adiponectin, which is also released in small amounts by the endothelium, possesses anti-inflammatory, anti-fibrotic and protective against endothelial injury properties. Both leptin and resistin exhibit features which are contradictory to adiponectin, as they trigger inflammation and the activation of skin fibroblasts. Epoprostenol is a prostaglandin analogue with powerful vasodilator activity and inhibitory effect on platelet aggregation. The aim of the study was to evaluate whether epoprostenol may have an effect on serum adipokine levels in patients with systemic sclerosis.

METHODS

A total of 27 patients were included in the study and received epoprostenol intravenously (25 µg of per day for 3 consecutive days). Serum concentrations of total adiponectin, resistin and leptin were assessed with enzyme-linked immunosorbent essay (R&D Systems, Minneapolis, MN, USA).

RESULTS

In all SSc patients, the basal level of adiponectin was significantly lower compared to healthy controls (mean 6.00 [Formula: see text] 2.81 μg/ml vs. 8.8 [Formula: see text] 4.3 μg/ml, p = 0.02) and basal level of resistin (mean 11.12 [Formula: see text] 3.36 ng/ml vs. 8.54 [Formula: see text] 3.07 ng/ml p = 0.02) was significantly higher than in the control group. The serum concentration of adiponectin increased significantly after treatment with epoprostenol (6.00 [Formula: see text] 2.81 μg/ml vs 9.29 [Formula: see text] 6.05 μg/ml; P = 0.002). The level of resistin and leptin remained unchanged.

CONCLUSION

Epoprostenol infusions up-regulate the serum concentration of adiponectin in patients with systemic sclerosis. In our opinion, future studies on treatments in systemic sclerosis should address the issue of their effect on adipokine metabolism.

Magnesium lithospermate B improves pulmonary artery banding induced right ventricular dysfunction by alleviating inflammation via p38MAPK pathway

BACKGROUD

Magnesium lithospermate B (MLB) is a major bioactive component of Slavia miltiorrhiza, which has been widely used in heart diseases on account of its anti-inflammatory, anti-oxidative, anti-proliferative and anti-fibrotic properties. Substance P(SP) is a small molecule neuropeptide, which was secreted much more during heart failure, and has an obvious function of immune enhancement and inflammation induction. This study aimed to investigate the protective effects of MLB on pulmonary artery banding (PAB) induced right ventricular (RV) dysfunction.

METHODS

The mouse model of PAB was established. The mice were intraperitoneal (IP) injection treated with MLB (10 mg kg^-1·d^-1) for 4 weeks and p38 mitogen-activated protein kinase (MAPK) activator was given at the same time. Echocardiography were performed on day 28. Then the hearts were harvested, and substance P (SP), inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and cardiac fibrosis were detected. The macrophages and fibroblasts were stimulated by SP separately, and then treated with MLB as well as p38MAPK activator. The inflammatory cytokines from macrophage, the proliferation and fibrosis of cardiac fibroblasts were measured. The expression of p38MAPK proteins were confirmed by immunoblotting.

FINDINGS

MLB preserved RV ejection fraction (EF), FS, RV/(LV + septum), HW/BW index and blunted RV inflammation as well as fibrosis. Phosphorylated-p38 (p-p38) MAPK was up-regulated, which was partially reversed by MLB treatment. However, p38MAPK activator abolished the effects of MLB on RV dysfunction, suggesting a key role of p38MPAK pathway in the effects of MLB reversing RV dysfunction. In external experiment, MLB reversed the increase of inflammatory cytokines from macrophage, the proliferation and fibrosis of cardiac fibroblasts which was simulated by SP. In accordance with in vivo study, p38MAPK activator abolished the effects of MLB on macrophage as well as fibroblasts.

INTERPRETATION

MLB improves PAB induced right ventricular remodeling by alleviating inflammation via p38MAPK pathway. Thus, MLB may offer the therapeutic potential for the patients of RV dysfunction.

Role of Inflammatory Cell Subtypes in Heart Failure

Inflammation is a well-known feature of heart failure. Studies have shown that while some inflammation is required for repair during injury and is protective, prolonged inflammation leads to myocardial remodeling and apoptosis of cardiac myocytes. Various types of immune cells are implicated in myocardial inflammation and include neutrophils, macrophages, eosinophils, mast cells, natural killer cells, T cells, and B cells. Recent clinical trials have targeted inflammatory cascades as therapy for heart failure with limited success. A better understanding of the temporal course of the infiltration of the different immune cells and their contribution to the inflammatory process may improve the success for therapy. This brief review outlines the major cell types involved in heart failure, and some of their actions are summarized in the supplementary figure.

Inhaled Pulmonary Vasodilators and Thoracic Organ Transplantation: Does Evidence Support Its Use and Cost Benefit?

In heart transplantation, pulmonary hypertension and increased pulmonary vascular resistance followed by donor right ventricular dysfunction remain a major cause of perioperative morbidity and mortality. In lung transplantation, primary graft dysfunction remains a major obstacle because it can cause bronchiolitis obliterans and mortality. Pulmonary vasodilators have been used as an adjunct therapy for heart or lung transplantation, mainly to treat pulmonary hypertension, right ventricular failure, and associated refractory hypoxemia. Among pulmonary vasodilators, inhaled nitric oxide is unique in that it is selective in pulmonary circulation and causes fewer systemic complications such as hypotension, flushing, or coagulopathy. Nitric oxide is expected to prevent or attenuate primary graft dysfunction by decreasing ischemia-reperfusion injury in lung transplantation. However, when considering the long-term benefit of these medications, little evidence supports their use in heart or lung transplantation. Current guidelines endorse inhaled vasodilators for managing immediate postoperative right ventricular failure in lung or heart transplantation, but no guidance is offered regarding agent selection, dosing, or administration. This review presents the current evidence of inhaled nitric oxide in lung or heart transplantation as well as comparisons with other pulmonary vasodilators including cost differences in consideration of economic pressures to contain rising pharmacy costs.

Inhibition of TLR9-NF-κB-mediated sterile inflammation improves pressure overload-induced right ventricular dysfunction in rats

Aims

Recent accumulating evidence suggests that sterile inflammation plays a crucial role in the progression of various cardiovascular diseases. However, its contribution to right ventricular (RV) dysfunction remains unknown. The aim of this study was to elucidate whether toll-like receptor 9 (TLR9)-NF-κB-mediated sterile inflammation plays a critical role in the pathogenesis of RV dysfunction.

Methods and results

We performed main pulmonary artery banding (PAB) in rats to induce RV pressure overload and dysfunction. On Day 14 after PAB, the pressure overload impaired RV function as indicated by increased RV end-diastolic pressure concomitant with macrophage infiltration and fibrosis, as well as maximal activation of NF-κB and TLR9. Short-term administration (days 14–16 after PAB) of a specific TLR9 inhibitor, E6446, or an NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC) significantly attenuated NF-κB activation. Furthermore, long-term administration of E6446 (treatment: days 14–28) or PDTC (prevention: days −1 to 28; treatment: days 14 to 28) improved RV dysfunction associated with mitigated macrophage infiltration and fibrosis in right ventricle and decreased serum brain natriuretic peptide levels.

Conclusion

Inhibition of TLR9-NF-κB pathway-mediated sterile inflammation improved PAB-induced RV dysfunction in rats. This pathway plays a major role in the progression of pressure overload-induced RV dysfunction and is potentially a novel therapeutic target for the disorder.

Dissecting Molecular Mechanisms Underlying Pulmonary Vascular Smooth Muscle Cell Dedifferentiation in Pulmonary Hypertension: Role of Mutated Caveolin-1 (Cav1F92A)-Bone Marrow Mesenchymal Stem Cells

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterised by remodelling in vascular smooth muscles, and switching from contractile (differentiated) to synthetic (dedifferentiated) phenotype. This study aimed to investigate the effect of a mutated caveolin-1 (Cav1^F92A) gene from bone marrow mesenchymal stem cells (rBMSCs) on phenotypic switching in the smooth muscle cells during PAH.

METHODS

Human pulmonary smooth muscle cells (HPASMCs) were treated with monocrotaline (MCT,1μM), and co-cultured with Cav1^F92A gene modified rBMSCs (rBMSCs/Cav1^F92A). The nitric oxide (NO) production, cell adhesion, cell viability and inflammatory cytokines expression in rBMSCs was measured to evaluate the survival rate of rBMSCs and the changes of inflammatory cytokines. The concentration of NO/cGMP (nitric oxide/Guanosine-3',5'-cyclic monophosphate), the tumour necrosis factor-alpha (TNF-α), transforming growth factor-beta1 (TGF-β1) mRNA, the expression of contractile smooth muscle cells (SMCs) phenotype markers (thrombospondin-1 and Matrix Gla protein, MGP), the synthetic SMCs phenotype markers (H-caldesmon and smooth muscle gene SM22 alpha, SM22α), cell migration and the morphological changes in rBMSCs/Cav1^F92A co-cultured HPASMCs were investigated.

RESULTS

Cav1^F92A increased NO concentration, cell adhesion, cell viability, anti-inflammatory cytokines interleukin-4 (IL-4), and interleukin-10 (IL-10), but decreased the inflammatory cytokines interleukin-1α (IL-1α), interferon-γ (INF-γ) and TNF-α expression in rBMSCs. rBMSCs/Cav1^F92A activated the NO/cGMP, down-regulated TNF-α, TGF-β1, thrombospondin-1 and MGP expression, up-regulated SM22α and H-caldesmon expression, restored cell morphology, and inhibited cell migration in MCT treated HPASMCs.

CONCLUSIONS

rBMSCs/Cav1^F92A inhibits switching from contractile to synthetic phenotype in HPASMCs. It also inhibits migration and promotes morphological restoration of these cells. rBMSCs/Cav1^F92A may be used as a therapeutic modality for PAH.

A current view of G protein-coupled receptor - mediated signaling in pulmonary hypertension: finding opportunities for therapeutic intervention

Pathological vascular remodeling is observed in various cardiovascular diseases including pulmonary hypertension (PH), a disease of unknown etiology that has been characterized by pulmonary artery vasoconstriction, right ventricular hypertrophy, vascular inflammation, and abnormal angiogenesis in pulmonary circulation. G protein-coupled receptors (GPCRs) are the largest family in the genome and widely expressed in cardiovascular system. They regulate all aspects of PH pathophysiology and represent therapeutic targets. We overview GPCRs function in vasoconstriction, vasodilation, vascular inflammation-driven remodeling and describe signaling cross talk between GPCR, inflammatory cytokines, and growth factors. Overall, the goal of this review is to emphasize the importance of GPCRs as critical signal transducers and targets for drug development in PH.

Inflammation in Right Ventricular Failure: Does It Matter?

Right ventricular (RV) failure is a common consequence of acute and chronic RV overload of pressure, such as after pulmonary embolism and pulmonary hypertension. It has been recently realized that symptomatology and survival of patients with pulmonary hypertension are essentially determined by RV function adaptation to increased afterload. Therefore, improvement of RV function and reversal of RV failure are treatment goals. Currently, the pathophysiology and the pathobiology underlying RV failure remain largely unknown. A better understanding of the pathophysiological processes involved in RV failure is needed, as there is no proven treatment for this disease at the moment. The present review aims to summarize the current understanding of the pathogenesis of RV failure, focusing on inflammation. We attempt to formally emphasize the importance of inflammation and associated representative inflammatory molecules and cells in the primum movens and development of RV failure in humans and in experimental models. We present inflammatory biomarkers and immune mediators involved in RV failure. We focus on inflammatory mediators and cells which seem to correlate with the deterioration of RV function and also explain how all these inflammatory mediators and cells might impact RV function adaptation to increased afterload. Finally, we also discuss the evidence on potential beneficial effects of targeted anti-inflammatory agents in the setting of acute and chronic RV failure.

Role of cardiac inflammation in right ventricular failure

Right ventricular failure (RVF) is the main determinant of mortality in patients with pulmonary arterial hypertension (PAH). Although the exact pathophysiology underlying RVF remains unclear, inflammation may play an important role, as it does in left heart failure. Perivascular pulmonary artery and systemic inflammation is relatively well studied and known to contribute to the initiation and maintenance of the pulmonary vascular insult in PAH. However, less attention has been paid to the role of cardiac inflammation in RVF and PAH. Consistent with many other types of heart failure, cardiac inflammation, triggered by systemic and local stressors, has been shown in RVF patients as well as in RVF animal models. RV inflammation likely contributes to impaired RV contractility, maladaptive remodelling and a vicious circle between RV and pulmonary vascular injury. Although the potential to improve RV function through anti-inflammatory therapy has not been tested, this approach has been applied clinically in left ventricular failure patients, with variable success. Because inflammation plays a dual role in the development of both pulmonary vascular pathology and RVF, anti-inflammatory therapies may have a potential double benefit in patients with PAH and associated RVF.

Fibroblasts and the extracellular matrix in right ventricular disease

Right ventricular failure predicts adverse outcome in patients with pulmonary hypertension (PH), and in subjects with left ventricular heart failure and is associated with interstitial fibrosis. This review manuscript discusses the cellular effectors and molecular mechanisms implicated in right ventricular fibrosis. The right ventricular interstitium contains vascular cells, fibroblasts, and immune cells, enmeshed in a collagen-based matrix. Right ventricular pressure overload in PH is associated with the expansion of the fibroblast population, myofibroblast activation, and secretion of extracellular matrix proteins. Mechanosensitive transduction of adrenergic signalling and stimulation of the renin-angiotensin-aldosterone cascade trigger the activation of right ventricular fibroblasts. Inflammatory cytokines and chemokines may contribute to expansion and activation of macrophages that may serve as a source of fibrogenic growth factors, such as transforming growth factor (TGF)-β. Endothelin-1, TGF-βs, and matricellular proteins co-operate to activate cardiac myofibroblasts, and promote synthesis of matrix proteins. In comparison with the left ventricle, the RV tolerates well volume overload and ischemia; whether the right ventricular interstitial cells and matrix are implicated in these favourable responses remains unknown. Expansion of fibroblasts and extracellular matrix protein deposition are prominent features of arrhythmogenic right ventricular cardiomyopathies and may be implicated in the pathogenesis of arrhythmic events. Prevailing conceptual paradigms on right ventricular remodelling are based on extrapolation of findings in models of left ventricular injury. Considering the unique embryologic, morphological, and physiologic properties of the RV and the clinical significance of right ventricular failure, there is a need further to dissect RV-specific mechanisms of fibrosis and interstitial remodelling.

Inflammatory Mediators Drive Adverse Right Ventricular Remodeling and Dysfunction and Serve as Potential Biomarkers

Adverse right ventricular (RV) remodeling leads to ventricular dysfunction and failure that represents an important determinant of outcome in patients with pulmonary hypertension (PH). Recent evidence indicates that inflammatory activation contributes to the pathogenesis of adverse RV remodeling and dysfunction. It has been shown that accumulation of inflammatory cells such as macrophages and mast cells in the right ventricle is associated with maladaptive RV remodeling. In addition, inhibition of inflammation in animal models of RV failure ameliorated RV structural and functional impairment. Furthermore, a number of circulating inflammatory mediators have been demonstrated to be associated with RV performance. This work reviews the role of inflammation in RV remodeling and dysfunction and discusses anti-inflammatory strategies that may attenuate adverse structural alterations while promoting improvement of RV function.

Predictors of Pericardial Effusion in Patients Undergoing Pulmonary Artery Banding

BACKGROUND

Although pulmonary artery banding (PAB) is a common palliative procedure for pediatric heart malformation, there are concerns of pressure overload and concomitant immune reactions in the right ventricle causing postsurgical complications such as pericardial effusion. At this time, no clear guidelines as to potential risk factors or procedural contraindications have been widely disseminated. Therefore, a study was undertaken to examine wide-ranging factors to find potential biomarkers for postsurgical pericardial effusion formation risk.

METHODS

A retrospective study was conducted on all cardiac surgeries performed over an eight-year period, and the main inclusion criterion was pericardial effusion development after PAB that required surgical drainage. Nine cases were then analyzed against a control group of 45 cases with respect to body measurements, concomitant surgeries, genetic screens, laboratory tests results, and cardiac function parameters.

RESULTS

Trisomy 21 was strongly associated with the development of severe pericardial effusion after PAB, and postoperative serum albumin levels in patients with trisomy 21 were associated with pericardial effusion development. Other parameters showed no significant correlation with pericardial effusion development.

CONCLUSIONS

Our data indicate a strong association between trisomy 21 and pericardial effusion requiring drainage after PAB, which is in line with translational research findings. Pressure overload from PAB may play a role in the formation of severe pericardial effusion that is exacerbated by cardiac structural defects commonly associated with trisomy 21. Surgical teams should therefore use caution and plan to implement drainage in PAB cases, and postoperative serum albumin may serve as a useful biomarker for pericardial effusion formation.

Subclinical Inflammation in Heart Failure: A Neutrophil Perspective

Although it is widely recognized that inflammation plays a critical role in the development and pathology of heart failure (HF), very little is known about the involvement of one of the most abundant immune cells in the blood, a primary immune response cell: the neutrophil. This review summarizes the current literature on the role of subclinical inflammation, with a focus on the neutrophil in the pathophysiology of the HF syndrome. Some emerging therapeutic strategies are also discussed.

Prostacyclins in Cardiac Surgery: Coming of Age

Prostacyclin (prostaglandin I2 [PGI2]) is an eicosanoid lipid mediator produced by the endothelial cells. It plays pivotal roles in vascular homeostasis by virtue of its potent vasodilatory and antithrombotic effects. Stable pharmacological analogues of PGI2 are used for treatment of pulmonary hypertension and right ventricular failure. PGI2 dose dependently inhibits platelet activation induced by adenosine-5′-diphosphate, arachidonic acid, collagen, and low-dose thrombin. This property has led to its use as an alternative to direct thrombin inhibitors in patients with type II heparin-induced thrombocytopenia (HIT) undergoing cardiac surgery. The aims of this review are the following: (1) to review the pharmacology of PGI2 and its derivatives, (2) to present the evidence for their use in pulmonary hypertension and right heart failure, and (3) to discuss their utility in the management of HIT in cardiac surgery.

Pressure overload leads to an increased accumulation and activity of mast cells in the right ventricle

Right ventricular (RV) remodeling represents a complex set of functional and structural adaptations in response to chronic pressure or volume overload due to various inborn defects or acquired diseases and is an important determinant of patient outcome. However, the underlying molecular mechanisms remain elusive. We investigated the time course of structural and functional changes in the RV in the murine model of pressure overload‐induced RV hypertrophy in C57Bl/6J mice. Using magnetic resonance imaging, we assessed the changes of RV structure and function at different time points for a period of 21 days. Pressure overload led to significant dilatation, cellular and chamber hypertrophy, myocardial fibrosis, and functional impairment of the RV. Progressive remodeling of the RV after pulmonary artery banding (PAB) in mice was associated with upregulation of myocardial gene markers of hypertrophy and fibrosis. Furthermore, remodeling of the RV was associated with accumulation and activation of mast cells in the RV tissue of PAB mice. Our data suggest possible involvement of mast cells in the RV remodeling process in response to pressure overload. Mast cells may thus represent an interesting target for the development of new therapeutic approaches directed specifically at the RV.

Epigenetics, inflammation and metabolism in right heart failure associated with pulmonary hypertension

Right ventricular failure (RVF) is the most important prognostic factor for both morbidity and mortality in pulmonary arterial hypertension (PAH), but also occurs in numerous other common diseases and conditions, including left ventricle dysfunction. RVF remains understudied compared with left ventricular failure (LVF). However, right and left ventricles have many differences at the morphological level or the embryologic origin, and respond differently to pressure overload. Therefore, knowledge from the left ventricle cannot be extrapolated to the right ventricle. Few studies have focused on the right ventricle and have permitted to increase our knowledge on the right ventricular-specific mechanisms driving decompensation. Here we review basic principles such as mechanisms accounting for right ventricle hypertrophy, dysfunction, and transition toward failure, with a focus on epigenetics, inflammatory, and metabolic processes.

Right ventricular end-diastolic stiffness heralds right ventricular failure in monocrotaline-induced pulmonary hypertension

Recent studies suggest right ventricular (RV) stiffness is important in pulmonary hypertension (PH) prognosis. Smaller stroke volume (SV) variation after a certain RV end-diastolic pressure (EDP) respiratory variation as assessed by spectral transfer function (STF) may identify RV stiffness. Our aim was to evaluate RV stiffness in monocrotaline (MCT)-induced PH progression and to validate STF gain between EDP and SV as marker of stiffness. Seven-week-old male Wistar rats randomly injected with 60 mg/kg MCT or vehicle were divided into three groups ( n = 12 each) according to cardiac index (CI): controls (Ctrl), preserved CI (MCT pCI), and reduced CI (MCT rCI). All underwent RV pressure-volume (PV) evaluation 24–34 days after MCT, under halogenate anesthesia and constant positive-pressure ventilation. End-diastolic stiffness (βi), end-systolic elastance (Eesi), arterial elastance for indexed volumes (Eai), and preload recruitable stroke work (PRSW) were obtained and beat-to-beat fluctuations during ventilation assessed by STF. Eai was the strongest determinant of CI, alongside βi but not PRSW. MCT rCI showed impaired ventricular-vascular coupling (VVC) and higher βi, along with low end-diastolic pressure (EDP) and stroke volume index (SVi) STF gain, denoting impaired preload reserve. On multivariate analysis βi and not Eesi correlated with EDP-SVi STF gain ( P < 0.001). Receiver-operating characteristics (ROC) curve analysis of EDP-SVi STF gain showed an area under curve of 0.84 for βi prediction ( P = 0.002). Afterload, impaired VVC and RV stiffness are major players in RV failure. RV stiffness can be assessed by STF gain analysis of respiratory fluctuations between EDP and SVi, which may constitute a prognostic tool in PH.

Roles of inflammation and apoptosis in experimental brain death-induced right ventricular failure

BACKGROUND

Right ventricular (RV) dysfunction remains the leading cause of early death after cardiac transplantation. Methylprednisolone is used to improve graft quality; however, evidence for that remains empirical. We sought to determine whether methylprednisolone, acting on inflammation and apoptosis, might prevent brain death-induced RV dysfunction.

METHODS

After randomization to placebo (n = 11) or to methylprednisolone (n = 8; 15 mg/kg), 19 pigs were assigned to a brain-death procedure. The animals underwent hemodynamic evaluation at 1 and 5 hours after Cushing reflex (i.e., hypertension and bradycardia). The animals euthanized, and myocardial tissue was sampled. This was repeated in a control group (n = 8).

RESULTS

At 5 hours after the Cushing reflex, brain death resulted in increased pulmonary artery pressure (27 ± 2 vs 18 ± 1 mm Hg) and in a 30% decreased ratio of end-systolic to pulmonary arterial elastances (Ees/Ea). Cardiac output and right atrial pressure did not change. This was prevented by methylprednisolone. Brain death-induced RV dysfunction was associated with increased RV expression of heme oxygenase-1, interleukin (IL)-6, IL-10, IL-1β, tumor necrosis factor (TNF)-α, IL-1 receptor-like (ST)-2, signal transducer and activator of transcription-3, intercellular adhesion molecules-1 and -2, vascular cell adhesion molecule-1, and neutrophil infiltration, whereas IL-33 expression decreased. RV apoptosis was confirmed by terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling staining. Methylprednisolone pre-treatment prevented RV-arterial uncoupling and decreased RV expression of TNF-α, IL-1 receptor-like-2, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and neutrophil infiltration. RV Ees/Ea was inversely correlated to RV TNF-α and IL-6 expression.

CONCLUSIONS

Brain death-induced RV dysfunction is associated with RV activation of inflammation and apoptosis and is partly limited by methylprednisolone.

Distinct right ventricle remodeling in response to pressure overload in the rat

Pulmonary arterial hypertension (PAH), the most serious chronic disorder of the pulmonary circulation, is characterized by pulmonary vasoconstriction and remodeling, resulting in increased afterload on the right ventricle (RV). In fact, RV function is the main determinant of prognosis in PAH. The most frequently used experimental models of PAH include monocrotaline- and chronic hypoxia-induced PAH, which primarily affect the pulmonary circulation. Alternatively, pulmonary artery banding (PAB) can be performed to achieve RV overload without affecting the pulmonary vasculature, allowing researchers to determine the RV-specific effects of their drugs/interventions. In this work, using two different degrees of pulmonary artery constriction, we characterize, in full detail, PAB-induced adaptive and maladaptive remodeling of the RV at 3 wk after PAB surgery. Our results show that application of a mild constriction resulted in adaptive hypertrophy of the RV, with preserved systolic and diastolic function, while application of a severe constriction resulted in maladaptive hypertrophy, with chamber dilation and systolic and diastolic dysfunction up to the isolated cardiomyocyte level. By applying two different degrees of constriction, we describe, for the first time, a reliable and short-duration PAB model in which RV adaptation can be distinguished at 3 wk after surgery. We characterize, in full detail, structural and functional changes of the RV in its response to moderate and severe constriction, allowing researchers to better study RV physiology and transition to dysfunction and failure, as well as to determine the effects of new therapies.

Challenges and opportunities in treating inflammation associated with pulmonary hypertension

INTRODUCTION

Inflammatory cells are present in the lungs from patients with many, if not all, forms of severe pulmonary hypertension.

AREAS COVERED

Historically the first inflammatory cell identified in the pulmonary vascular lesions was the mast cell. T and B lymphocytes, as well as macrophages, are present in and around the pulmonary arterioles and many patients have elevated blood levels of interleukin 1 and 6; some patients show elevated levels of leukotriene B4. An overlap between collagen-vascular disease-associated pulmonary arterial hypertension (PAH) and idiopathic PAH exists, yet only a few studies have been designed that evaluate the effect of anti-inflammatory treatments. Here we review the pertinent data that connect PAH and inflammation/autoimmune dysregulation and evaluate experimental models of severe PAH with an emphasis on the Sugen/athymic rat model of severe PAH. Expert commentary: We postulate that there are several inflammatory phenotypes and predict that there will be several anti-inflammatory treatment strategies for severe PAH.