Expression of monocyte chemoattractant protein-1 in idiopathic dilated cardiomyopathy

Heart Failure With Preserved Ejection Fraction: Will Cardiac Magnetic Imaging Impact on Diagnosis, Treatment, and Outcomes?: Explaining the Need for Advanced Imaging to Clinical Stakeholders

Clinicians frequently equate symptoms of volume overload to heart failure (HF) but such generalization may preclude diagnostic or etiologic precision essential to optimizing outcomes. HF itself must be specified as the disparate types of cardiac pathology have been traditionally surmised by examination of left ventricular (LV) ejection fraction (EF) as either HF with preserved LVEF (HFpEF-LVEF >50%) or reduced LVEF of (HFrEF-LVEF <40%). More recent data support a third, potentially transitional HF subtype, but therapy, assessment, and prognosis have been historically dictated within the corresponding LV metrics determined by echocardiography. The present effort asks whether this historically dominant role of echocardiography is now shifting slightly, becoming instead a shared if not complimentary test. Will there be a gradual increasing profile for cardiac magnetic resonance as the attempt to further refine our understanding, diagnostic accuracy, and outcomes for HFpEF is attempted?

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

The immune response holds a pivotal role in cardiovascular disease development. As multifunctional cells of the innate immune system, macrophages play an essential role in initial inflammatory response that occurs following cardiovascular injury, thereby inducing subsequent damage while also facilitating recovery. Meanwhile, the diverse phenotypes and phenotypic alterations of macrophages strongly associate with distinct types and severity of cardiovascular diseases, including coronary heart disease, valvular disease, myocarditis, cardiomyopathy, heart failure, atherosclerosis and aneurysm, which underscores the importance of investigating macrophage regulatory mechanisms within the context of specific diseases. Besides, recent strides in single-cell sequencing technologies have revealed macrophage heterogeneity, cell-cell interactions, and downstream mechanisms of therapeutic targets at a higher resolution, which brings new perspectives into macrophage-mediated mechanisms and potential therapeutic targets in cardiovascular diseases. Remarkably, myocardial fibrosis, a prevalent characteristic in most cardiac diseases, remains a formidable clinical challenge, necessitating a profound investigation into the impact of macrophages on myocardial fibrosis within the context of cardiac diseases. In this review, we systematically summarize the diverse phenotypic and functional plasticity of macrophages in regulatory mechanisms of cardiovascular diseases and unprecedented insights introduced by single-cell sequencing technologies, with a focus on different causes and characteristics of diseases, especially the relationship between inflammation and fibrosis in cardiac diseases (myocardial infarction, pressure overload, myocarditis, dilated cardiomyopathy, diabetic cardiomyopathy and cardiac aging) and the relationship between inflammation and vascular injury in vascular diseases (atherosclerosis and aneurysm). Finally, we also highlight the preclinical/clinical macrophage targeting strategies and translational implications.

The Molecular Role of Immune Cells in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a rare and severe condition characterized by chamber dilation and impaired contraction of the left ventricle. It constitutes a fundamental etiology for profound heart failure and abrupt cardiac demise, rendering it a prominent clinical indication for heart transplantation (HTx) among both adult and pediatric populations. DCM arises from various etiologies, including genetic variants, epigenetic disorders, infectious insults, autoimmune diseases, and cardiac conduction abnormalities. The maintenance of cardiac function involves two distinct types of immune cells: resident immune cells and recruited immune cells. Resident immune cells play a crucial role in establishing a harmonious microenvironment within the cardiac tissue. Nevertheless, in response to injury, cardiomyocytes initiate a cytokine cascade that attracts peripheral immune cells, thus perturbing this intricate equilibrium and actively participating in the initiation and pathological remodeling of dilated cardiomyopathy (DCM), particularly during the progression of myocardial fibrosis. Additionally, immune cells assume a pivotal role in orchestrating the inflammatory processes, which are intimately linked to the prognosis of DCM. Consequently, understanding the molecular role of various immune cells and their regulation mechanisms would provide an emerging era for managing DCM. In this review, we provide a summary of the most recent advancements in our understanding of the molecular mechanisms of immune cells in DCM. Additionally, we evaluate the effectiveness and limitations of immunotherapy approaches for the treatment of DCM, with the aim of optimizing future immunotherapeutic strategies for this condition.

Lifetime Evaluation of Left Ventricular Structure and Function in Male C57BL/6J Mice after Gamma and Space-Type Radiation Exposure

The lifetime effects of space irradiation (IR) on left ventricular (LV) function are unknown. The cardiac effects induced by space-type IR, specifically 5-ion simplified galactic cosmic ray simulation (simGCRsim), are yet to be discovered. Three-month-old, age-matched, male C57BL/6J mice were irradiated with 137Cs gamma (γ; 100, 200 cGy) and simGCRsim (50 and 100 cGy). LV function was assessed via transthoracic echocardiography at 14 and 28 days (early), and at 365, 440, and 660 (late) days post IR. We measured the endothelial function marker brain natriuretic peptide in plasma at three late timepoints. We assessed the mRNA expression of the genes involved in cardiac remodeling, fibrosis, inflammation, and calcium handling in LVs harvested at 660 days post IR. All IR groups had impaired global LV systolic function at 14, 28, and 365 days. At 660 days, 50 cGy simGCRsim-IR mice exhibited preserved LV systolic function with altered LV size and mass. At this timepoint, the simGCRsim-IR mice had elevated levels of cardiac fibrosis, inflammation, and hypertrophy markers Tgfβ1, Mcp1, Mmp9, and βmhc, suggesting that space-type IR may induce the cardiac remodeling processes that are commonly associated with diastolic dysfunction. IR groups showing statistical significance were modeled to calculate the Relative Biological Effectiveness (RBE) and Radiation Effects Ratio (RER). The observed dose-response shape did not indicate a lower threshold at these IR doses. A single full-body IR at doses of 100-200 cGy for γ-IR, and 50-100 cGy for simGCRsim-IR decreases the global LV systolic function in WT mice as early as 14 and 28 days after exposure, and at 660 days post IR. Interestingly, there is an intermediate time point (365 days) where the impairment in LV function is observed. These findings do not exclude the possibility of increased acute or degenerative cardiovascular disease risks at lower doses of space-type IR, and/or when combined with other space travel-associated stressors such as microgravity.

Role of PI3K/Akt signaling pathway in cardiac fibrosis

Heart failure (HF) is considered as a severe health problem worldwide, while cardiac fibrosis is one of the main driving factors for the progress of HF. Cardiac fibrosis was characterized by changes in cardiomyocytes, cardiac fibroblasts, ratio of collagen (COL) I/III, and the excessive production and deposition of extracellular matrix (ECM), thus forming a scar tissue, which leads to pathological process of cardiac structural changes and systolic as well as diastolic dysfunction. Cardiac fibrosis is a common pathological change of many advanced cardiovascular diseases including ischemic heart disease, hypertension, and HF. Accumulated studies have proven that phosphoinositol-3 kinase (PI3K)/Akt signaling pathway is involved in regulating the occurrence, progression and pathological formation of cardiac fibrosis via regulating cell survival, apoptosis, growth, cardiac contractility and even the transcription of related genes through a series of molecules including mammalian target of rapamycin (mTOR), glycogen synthase kinase 3 (GSK-3), forkhead box proteins O1/3 (FoxO1/3), and nitric oxide synthase (NOS). Thus, the review focuses on the role of PI3K/Akt signaling pathway in the cardiac fibrosis. The information reviewed here should be significant in understanding the role of PI3K/Akt in cardiac fibrosis and contribute to the design of further studies related to PI3K/Akt and the cardiac fibrotic response, as well as sought to shed light on a potential treatment for cardiac fibrosis.

Involvement of chronic inflammation via monocyte chemoattractant protein-1 in uraemic cardiomyopathy: a human biopsy study

Aims

Patients undergoing dialysis, even those without coronary artery disease or valvular abnormalities, sometimes present with reduced heart function, which resembles dilated cardiomyopathy (DCM). This condition is known as uraemic cardiomyopathy (UCM). The mechanisms of UCM development are not fully understood. Previous studies demonstrated that the balance between placental growth factor (PlGF) and fms‐like tyrosine kinase‐1 (Flt‐1) is correlated with renal function, and PlGF/Flt‐1 signalling is involved in the development of cardiovascular diseases in patients with chronic kidney disease. This study was conducted to evaluate the pathogenesis of UCM and clarify the differences in the mechanisms of UCM and DCM by using human endomyocardial biopsy and blood samples.

Methods and results

The clinical and pathological features of 30 patients on dialysis with reduced cardiac function [left ventricular ejection fraction (LVEF) ≤50%] (UCM group; mean age: 58.5 ± 9.4 years and LVEF: 39.1 ± 7.2%), 196 DCM patients (DCM group; mean age: 62.7 ± 14.0 years and LVEF: 33.5 ± 8.8%) as controls with reduced cardiac function (LVEF ≤ 45%), and 21 patients as controls with normal cardiac function (control group; mean age: 56.2 ± 19.3 years and LVEF: 67.5 ± 6.7%) were analysed. The percentage of the interstitial fibrosis area in the UCM group was greater than that in the DCM group (P = 0.045). In UCM patients, the percentage of the interstitial fibrosis area was positively correlated with the duration of renal replacement therapy (P < 0.001). The number of infiltrated CD68‐positive macrophages in the myocardium and expression of monocyte chemoattractant protein‐1 (MCP‐1) in cardiomyocytes were significantly greater in the UCM group than in the other groups (P < 0.001, respectively). Furthermore, while the serum level of soluble form of Flt‐1, an endogenous inhibitor of PlGF, in the UCM group was lower compared with that in the DCM group (P < 0.001), the serum levels of PlGF and PlGF/soluble form of Flt‐1 ratio and plasma level of MCP‐1 in the UCM group were higher than those in the DCM group (P < 0.001, respectively).

Conclusions

These results suggest that activated PlGF/Flt‐1 signalling and subsequent macrophage‐mediated chronic non‐infectious inflammation via MCP‐1 in the myocardium are involved in the pathogenesis of UCM.

Cellular and Molecular Differences between HFpEF and HFrEF: A Step Ahead in an Improved Pathological Understanding

Heart failure (HF) is the most rapidly growing cardiovascular health burden worldwide. HF can be classified into three groups based on the percentage of the ejection fraction (EF): heart failure with reduced EF (HFrEF), heart failure with mid-range-also called mildly reduced EF- (HFmrEF), and heart failure with preserved ejection fraction (HFpEF). HFmrEF can progress into either HFrEF or HFpEF, but its phenotype is dominated by coronary artery disease, as in HFrEF. HFrEF and HFpEF present with differences in both the development and progression of the disease secondary to changes at the cellular and molecular level. While recent medical advances have resulted in efficient and specific treatments for HFrEF, these treatments lack efficacy for HFpEF management. These differential response rates, coupled to increasing rates of HF, highlight the significant need to understand the unique pathogenesis of HFrEF and HFpEF. In this review, we summarize the differences in pathological development of HFrEF and HFpEF, focussing on disease-specific aspects of inflammation and endothelial function, cardiomyocyte hypertrophy and death, alterations in the giant spring titin, and fibrosis. We highlight the areas of difference between the two diseases with the aim of guiding research efforts for novel therapeutics in HFrEF and HFpEF.

Tissue thrombin is associated with the pathogenesis of dilated cardiomyopathy

BACKGROUND

Thrombin is a serine protease known to be the final product of the coagulation cascade. However, thrombin plays other physiological roles in processes such as gastric contractions and vessel wound healing, and a state of coagulability is increased in patients with dilated cardiomyopathy (DCM). In this study, we investigate the role of thrombin in the pathogenesis of DCM. The purpose of this study is to clarify the role of thrombin in the pathogenesis of DCM and investigate the possibility of treatment against DCM by thrombin inhibition.

METHODS

We investigated the expression of thrombin in the left ventricles of five patients with DCM who underwent the Batista operation and four patients without heart disease. Furthermore, we investigated the involvement of thrombin in the development of DCM using knock-in mice with a deletion mutation of cardiac troponin T that causes human DCM (∆K210 knock-in mouse) (B6;129-Tnnt2^tm2Mmto) and assessed the effects of a direct thrombin inhibitor, dabigatran on ∆K210 knock-in mice using echocardiographic examinations, the Kaplan-Meier method and Western blotting.

RESULTS

The immunohistochemical analysis showed a strong thrombin expression in the DCM patients compared to the patients without heart disease. In immunohistochemical analysis, a strong thrombin expression was observed in the heart tissues analysis in the ∆K210 knock-in mice. Dabigatran administration significantly improved fractional shortening according to the echocardiographic examination and the survival outcomes in ∆K210 knock-in mice.

CONCLUSION

Tissue thrombin is involved in the pathogenesis of DCM and thrombin inhibition can be beneficial for the treatment of DCM.

Chemokines and Heart Disease: A Network Connecting Cardiovascular Biology to Immune and Autonomic Nervous Systems

Among the chemokines discovered to date, nineteen are presently considered to be relevant in heart disease and are involved in all stages of cardiovascular response to injury. Chemokines are interesting as biomarkers to predict risk of cardiovascular events in apparently healthy people and as possible therapeutic targets. Moreover, they could have a role as mediators of crosstalk between immune and cardiovascular system, since they seem to act as a “working-network” in deep linkage with the autonomic nervous system. In this paper we will describe the single chemokines more involved in heart diseases; then we will present a comprehensive perspective of them as a complex network connecting the cardiovascular system to both the immune and the autonomic nervous systems. Finally, some recent evidences indicating chemokines as a possible new tool to predict cardiovascular risk will be described.

Effect of vildagliptin, a dipeptidyl peptidase 4 inhibitor, on cardiac hypertrophy induced by chronic beta-adrenergic stimulation in rats

Background

Heart failure with left ventricular (LV) hypertrophy is often associated with insulin resistance and inflammation. Recent studies have shown that dipeptidyl peptidase 4 (DPP4) inhibitors improve glucose metabolism and inflammatory status. We therefore evaluated whether vildagliptin, a DPP4 inhibitor, prevents LV hypertrophy and improves diastolic function in isoproterenol-treated rats.

Methods

Male Wistar rats received vehicle (n = 20), subcutaneous isoproterenol (2.4 mg/kg/day, n = 20) (ISO), subcutaneous isoproterenol (2.4 mg/kg/day + oral vildagliptin (30 mg/kg/day, n = 20) (ISO-VL), or vehicle + oral vildagliptin (30 mg/kg/day, n = 20) (vehicle-VL) for 7 days.

Results

Blood pressure was similar among the four groups, whereas LV hypertrophy was significantly decreased in the ISO-VL group compared with the ISO group (heart weight/body weight, vehicle: 3.2 ± 0.40, ISO: 4.43 ± 0.39, ISO-VL: 4.14 ± 0.29, vehicle-VL: 3.16 ± 0.16, p < 0.05). Cardiac catheterization revealed that vildagliptin lowered the elevated LV end-diastolic pressure observed in the ISO group, but other parameters regarding LV diastolic function such as the decreased minimum dp/dt were not ameliorated in the ISO-VL group. Histological analysis showed that vildagliptin attenuated the increased cardiomyocyte hypertrophy and perivascular fibrosis, but it did not affect angiogenesis in cardiac tissue. In the ISO-VL group, quantitative PCR showed attenuation of increased mRNA expression of tumor necrosis factor-α, interleukin-6, insulin-like growth factor-l, and restoration of decreased mRNA expression of glucose transporter type 4.

Conclusions

Vildagliptin may prevent LV hypertrophy caused by continuous exposure to isoproterenol in rats.

MCP-1and IL-1β expression in the myocardia of two young patients with Type 1 diabetes mellitus and fatal diabetic ketoacidosis

Convincing evidence exists for the early onset of diabetic cardiomyopathy and coronary artery disease (CAD) as distinct forms of cardiac disease in young patients with Type 1 diabetes mellitus (T1DM) and the pre-stages of T2DM, forms of dysregulated insulin signaling. Progression of both chronic cardiac conditions is mediated by oxidative stress and low grade inflammation. This study reports the expression of monocyte chemotactic protein-1 (MCP-1) chemokine and the interleukin (IL)-1β inflammatory cytokine in two young patients with suboptimal metabolic control and fatal diabetic ketoacidosis (DKA), two age-matched overweight/obesity cases and two age-matched controls. In addition, markers of oxidative stress, apoptosis, collagen deposition and cardiomyocyte hypertrophy were studied. Significant expression of MCP-1 and IL-1β was seen in the myocardia of the T1DM/DKA cases, with lesser amounts expressed in the overweight/obesity myocardia. All of the other markers except cardiomyocyte hypertrophy were expressed to a significantly greater extent in the T1DM/DKA and overweight/obesity cases in comparison to the age-matched controls. Cardiomyocyte hypertrophy was significantly greater in the overweight/obesity cases than in the T1DM/DKA or the control cases.

Elevated oxidative stress is associated with ventricular fibrillation episodes in patients with Brugada-type electrocardiogram without SCN5A mutation

BACKGROUND

Brugada syndrome is a disease known to cause ventricular fibrillation with a structurally normal heart and is linked to SCN5A gene mutation. However, the mechanism by which ventricular fibrillation develops in cases of Brugada-type electrocardiogram without SCN5A mutation has remained unclear. Recently, oxidative stress has been implicated in the pathophysiology of cardiac arrhythmia. We also investigated oxidative stress levels in the myocardia of patients with Brugada-type electrocardiogram.

METHODS

Endomyocardial biopsy samples were obtained from 68 patients with Brugada-type electrocardiogram (66 males and two females). We performed histological and immunohistochemical analyses for CD45, CD68, and 4-hydroxy-2-nonenal-modified protein, which is a major lipid peroxidation product.

RESULTS

SCN5A mutation was detected in 14 patients. Ventricular fibrillation was documented in three patients with SCN5A mutation and in 11 without SCN5A mutation. In patients with SCN5A mutation, 4-hydroxy-2-nonenal-modified protein-positive area was not significantly different between the documented ventricular fibrillation (VF) group (VF+ group) and the group without documented VF (VF- group). However, in patients without SCN5A, the area was significantly larger in the VF+ group than that in the VF- group (P<.05). All other parameters (fibrosis area, CD45, and CD68) were not different between the VF+ and VF- group in both SCN5A+ and SCN5A- patients.

CONCLUSION

Oxidative stress is elevated in the myocardium of patients with Brugada-type electrocardiogram who have VF episodes and do not have SCN5A gene mutations. Oxidative stress may be associated with the occurrence of VF in patients with Brugada-type electrocardiogram without SCN5A mutation.

Relationship between circulating levels of monocyte chemoattractant protein-1 and systolic dysfunction in patients with hypertrophic cardiomyopathy

BACKGROUND

Progression of hypertrophic cardiomyopathy (HCM) to left ventricular dilatation and systolic dysfunction sometimes occurs. However, the mechanism of the transition from hypertrophy to dysfunction has not been elucidated. It has been reported that circulating levels of monocyte chemoattractant protein-1 (MCP-1), which is a major factor promoting the accumulation of macrophages, are increased in patients with congestive heart failure. We measured circulating levels of MCP-1 in patients with HCM and examined whether MCP-1 was expressed in the myocardium of HCM patients. We also examined whether circulating levels of MCP-1 were correlated with left ventricular dysfunction.

METHODS

Circulating levels of MCP-1 were measured by an enzyme immunoassay in 26 patients with HCM (60+/-2 years old) and 20 control subjects (57+/-2 years old). Cardiac function was evaluated by two-dimensional echocardiography and cardiac catheterization.

RESULTS

HCM patients had significantly elevated levels of MCP-1 (HCM: 309+/-30 vs. control: 178+/-8 pg/ml, P<.001). MCP-1 levels in patients with systolic dysfunction were significantly higher than those in patients without systolic dysfunction (P<.05) and were also significantly higher than those in patients with outflow obstruction (P<.05). Immunohistochemical analysis revealed that MCP-1 was expressed in endomyocardial biopsy samples obtained from HCM patients with systolic dysfunction. Furthermore, MCP-1 levels were inversely correlated with fractional shortening (r=-.401, P<.05) and correlated with left ventricular end-diastolic pressure (r=-.579, P<.01).

CONCLUSION

These results show that MCP-1 is associated with, and might be involved in the pathogenesis of, left ventricular systolic dysfunction in patients with HCM.