Circulating biomarkers of collagen metabolism in cardiac diseases

Early- to mid-gestational testosterone excess leads to adverse cardiac outcomes in postpartum sheep

Cardiovascular dysfunctions complicate 10-20% of pregnancies, increasing the risk for postpartum mortality. Various gestational insults, including preeclampsia are reported to be associated with adverse maternal cardiovascular outcomes. One such insult, gestational hyperandrogenism increases the risk for preeclampsia and other gestational morbidities but its impact on postpartum maternal health is not well known. We hypothesize that gestational hyperandrogenism such as testosterone (T) excess will adversely impact the maternal heart in the postpartum period. Pregnant ewes were injected with T propionate from day 30 to day 90 of gestation (term 147 days). Three months postpartum, echocardiograms, plasma cytokine profiles, cardiac morphometric, and molecular analysis were conducted [control (C) n = 6, T-treated (T) n = 7 number of animals]. Data were analyzed by two-tailed Student's t test and Cohen's effect size (d) analysis. There was a nonsignificant large magnitude decrease in cardiac output (7.64 ± 1.27 L/min vs. 10.19 ± 1.40, P = 0.22, d = 0.81) and fractional shortening in the T ewes compared with C (35.83 ± 2.33% vs. 41.50 ± 2.84, P = 0.15, d = 0.89). T treatment significantly increased 1) left ventricle (LV) weight-to-body weight ratio (2.82 ± 0.14 g/kg vs. 2.46 ± 0.08) and LV thickness (14.56 ± 0.52 mm vs. 12.50 ± 0.75), 2) proinflammatory marker [tumor necrosis factor-alpha (TNF-α)] in LV (1.66 ± 0.35 vs. 1.06 ± 0.18), 3) LV collagen (Masson's Trichrome stain: 3.38 ± 0.35 vs. 1.49 ± 0.15 and Picrosirius red stain: 5.50 ± 0.32 vs. 3.01 ± 0.23), 4) markers of LV apoptosis, including TUNEL (8.3 ± 1.1 vs. 0.9 ± 0.18), bcl-2-associated X protein (Bax)+-to-b-cell lymphoma 2 (Bcl2)+ ratio (0.68 ± 0.30 vs. 0.13 ± 0.02), and cleaved caspase 3 (15.4 ± 1.7 vs. 4.4 ± 0.38). These findings suggest that gestational testosterone excess adversely programs the maternal LV, leading to adverse structural and functional consequences in the postpartum period.NEW & NOTEWORTHY Using a sheep model of human translational relevance, this study provides evidence that excess gestational testosterone exposure such as that seen in hyperandrogenic disorders adversely impacts postpartum maternal hearts.

MicroRNA-452-5p regulates fibrogenesis via targeting TGF-β/SMAD4 axis in SCN5A-knockdown human cardiac fibroblasts

The mutated SCN5A gene encoding defective Nav1.5 protein causes arrhythmic ailments and is associated with enhanced cardiac fibrosis. This study investigated whether SCN5A mutation directly affects cardiac fibroblasts and explored how defective SCN5A relates to cardiac fibrosis. SCN5A knockdown (SCN5AKD) human cardiac fibroblasts (HCF) had higher collagen, α-SMA, and fibronectin expressions. Micro-RNA deep sequencing and qPCR analysis revealed the downregulation of miR-452-5p and bioinformatic analysis divulged maladaptive upregulation of transforming growth factor β (TGF-β) signaling in SCN5AKD HCF. Luciferase reporter assays validated miR-452-5p targets SMAD4 in SCN5AKD HCF. Moreover, miR-452-5p mimic transfection in SCN5AKD HCF or AAV9-mediated miR-452-5p delivery in isoproterenol-induced heart failure (HF) rats, resulted in the attenuation of TGF-β signaling and fibrogenesis. The exogenous miR-452-5p significantly improved the poor cardiac function in HF rats. In conclusion, miR-452-5p regulates cardiac fibrosis progression by targeting the TGF-β/SMAD4 axis under the loss of the SCN5A gene.

Muscle quality, physical performance, and comorbidity are predicted by circulating procollagen type III N-terminal peptide (P3NP): the InCHIANTI follow-up study

Sarcopenia is characterized by skeletal muscle quantitative and qualitative alterations. A marker of collagen turnover, procollagen type III N-terminal peptide (P3NP), seems to be related to those conditions. This study aims to assess the predictive role of P3NP in muscle density and physical performance changes. In the InCHIANTI study, a representative sample from the registry lists of two towns in Tuscany, Italy, was recruited. Baseline data was collected in 1998, and follow-up visits were conducted every 3 years. Out of the 1453 participants enrolled at baseline, this study includes 1052 participants. According to P3NP median levels, population was clustered in two groups; 544 (51.7%) of the 1052 subjects included were classified in the low median levels (LM-P3NP); at the baseline, they were younger, had higher muscle density, and performed better at the Short Physical Performance Battery (SPPB), compared to the high-median group (HM-P3NP).LM-P3NP cases showed a lower risk to develop liver chronic diseases, CHF, myocardial infarction, and osteoarthritis. HM-P3NP levels were associated with a longitudinal reduction of muscle density, and this effect was potentiated by the interaction between P3NP and leptin. Moreover, variation in physical performance was inversely associated with high level of P3NP, and directly associated with high fat mass, and with the interaction between P3NP and muscle density. Our data indicate that P3NP is associated with the aging process, affecting body composition, physical performance, and clinical manifestations of chronic degenerative age-related diseases.

Cardiac remodeling associated with chronic kidney disease is enhanced in a rat model of metabolic syndrome: Preparation of mesenchymal transition

Cardiac alteration due to chronic kidney disease is described by tissue fibrosis. This remodeling involves myofibroblasts of various origins, including epithelial or endothelial to mesenchymal transitions. In addition, obesity and insulin resistance together or separately seem to exacerbate cardiovascular risk in chronic kidney disease (CKD). The main objective of this study was to assess if pre-existing metabolic disease exacerbates CKD-induced cardiac alterations. In addition, we hypothesised that endothelial to mesenchymal transition participates in this enhancement of cardiac fibrosis. Rats fed cafeteria type diet for 6 months underwent a subtotal nephrectomy at 4 months. Cardiac fibrosis was evaluated by histology and qRT-PCR. Collagens and macrophages were quantified by immunohistochemistry. Endothelial to mesenchymal transitions were assessed by qRT-PCR (CD31, VE-cadherin, α-SMA, nestin) and also by CD31 immunofluorescence staining. Rats fed with cafeteria type regimen were obese, hypertensive and insulin resistant. Cardiac fibrosis was predominant in CKD rats and was highly majored by cafeteria regimen. Collagen-1 and nestin expressions were higher in CKD rats, independently of regimen. Interestingly, in rats with CKD and cafeteria diet we found an increase of CD31 and α-SMA co-staining with suggest an implication of endothelial to mesenchymal transition during heart fibrosis. We showed that rats already obese and insulin resistant had an enhanced cardiac alteration to a subsequent renal injury. Cardiac fibrosis process could be supported by a involvement of the endothelial to mesenchymal transition phenomenon.

Transcriptional Activity of Metalloproteinase 9 (MMP-9) and Tissue Metalloproteinase 1 (TIMP-1) Genes as a Diagnostic and Prognostic Marker of Heart Failure Due to Ischemic Heart Disease

The most common cause of heart failure (HF) is coronary artery disease (CAD). The aim of this study was to evaluate the transcriptional activity of the metalloproteinase 9 (MMP-9) and tissue metalloproteinase inhibitor 1 (TIMP-1) genes in a study group of patients with HF due to CAD and in the control group, as well as assess the transcriptional activity of the examined genes, taking into account the number of affected coronary arteries and the severity of heart failure. The study group consisted of a total of 150 (100%) patients. The material for the study was peripheral blood, and molecular tests were performed using the quantitative QRT-PCR technique. The transcriptional activity of the MMP-9 gene was significantly higher in the group of patients with CAD and HF. It was also significantly higher with the progression of heart failure. TIMP-1 gene transcriptional activity was significantly lower with the advancement of heart failure. The transcriptional activity of the MMP-9 and TIMP-1 genes differentiated the examined patients. The severity of HF, and a significant increase in the QRT-PCR transcriptional activity of the MMP-9 gene with a simultaneous decrease in the activity of the TIMP-1 gene, makes them useful diagnostic and prognostic markers in clinical practice.

Bioactive Compounds and Cardiac Fibrosis: Current Insight and Future Prospect

Cardiac fibrosis is a pathological condition characterized by excessive deposition of collagen and other extracellular matrix components in the heart. It is recognized as a major contributor to the development and progression of heart failure. Despite significant research efforts in characterizing and identifying key molecular mechanisms associated with myocardial fibrosis, effective treatment for this condition is still out of sight. In this regard, bioactive compounds have emerged as potential therapeutic antifibrotic agents due to their anti-inflammatory and antioxidant properties. These compounds exhibit the ability to modulate fibrogenic processes by inhibiting the production of extracellular matrix proteins involved in fibroblast to myofibroblast differentiation, or by promoting their breakdown. Extensive investigation of these bioactive compounds offers new possibilities for preventing or reducing cardiac fibrosis and its detrimental consequences. This comprehensive review aims to provide a thorough overview of the mechanisms underlying cardiac fibrosis, address the limitations of current treatment strategies, and specifically explore the potential of bioactive compounds as therapeutic interventions for the treatment and/or prevention of cardiac fibrosis.

Senescent cardiac fibroblasts: A key role in cardiac fibrosis

Cardiac fibroblasts are a cell population that controls the homeostasis of the extracellular matrix and orchestrates a damage response to maintain cardiac architecture and performance. Due to these functions, fibroblasts play a central role in cardiac fibrosis development, and there are large differences in matrix protein secretion profiles between fibroblasts from aged versus young animals. Senescence is a multifactorial and complex process that has been associated with inflammatory and fibrotic responses. After damage, transient cellular senescence is usually beneficial, as these cells promote tissue repair. However, the persistent presence of senescent cells within a tissue is linked with fibrosis development and organ dysfunction, leading to aging-related diseases such as cardiovascular pathologies. In the heart, early cardiac fibroblast senescence after myocardial infarction seems to be protective to avoid excessive fibrosis; however, in non-infarcted models of cardiac fibrosis, cardiac fibroblast senescence has been shown to be deleterious. Today, two new classes of drugs, termed senolytics and senostatics, which eliminate senescent cells or modify senescence-associated secretory phenotype, respectively, arise as novel therapeutical strategies to treat aging-related pathologies. However, further studies will be needed to evaluate the extent of the utility of senotherapeutic drugs in cardiac diseases, in which pathological context and temporality of the intervention must be considered.

Relationship between atrial fibrillation and a liver fibrogenesis marker in patients with acute heart failure

BACKGROUND

Hemodynamic disturbance in heart failure (HF) induces extra-cardiac organ injury. Atrial fibrillation (AF) is common in patients with HF. The relationship between AF and organ injury in HF remains unclear. We investigated the relationship between AF and the liver fibrosis marker, type IV collagen 7S (P4NP 7S) in patients with HF.

METHODS AND RESULTS

From a pooled dataset of 3 observational cohorts of hospitalized HF, 720 patients in whom P4NP 7S was measured before discharge were included. Median P4NP 7S were 5.1, 5.3, and 6.2 ng/mL in the sinus rhythm (SR) (n = 368), paroxysmal AF (n = 67), and persistent AF (n = 285) groups, respectively (P < 0.001). In the multiple linear regression analysis, the significant association with P4NP 7S was found for persistent AF (P < 0.001). The cumulative 1-year incidence of the primary composite endpoint of cardiac death and HF hospitalization were 27.6, 24.1, and 34.5% in the SR, paroxysmal AF, and persistent AF groups, respectively (Log-rank P = 0.07) and 25.3 and 34.5% in the low (below median) and high P4NP 7S groups, respectively (Log-rank P = 0.005). The adjusted risks of persistent AF versus SR and high P4NP 7S versus low P4NP 7S for the primary endpoint were 1.38 (95% confidence interval 1.02-1.89) and 1.52 (1.14-2.03), respectively. When patients were divided based on a combination of AF and P4NP 7S, concomitant persistent AF and high P4NP 7S portended a dismal prognosis.

CONCLUSION

AF is associated with an increase in the liver fibrosis marker. Co-presence of persistent AF and P4NP 7S may portend adverse clinical outcomes.

The immunomodulatory role of matrix metalloproteinases in colitis-associated cancer

Matrix metalloproteinases (MMPs) are an important class of enzymes in the body that function through the extracellular matrix (ECM). They are involved in diverse pathophysiological processes, such as tumor invasion and metastasis, cardiovascular diseases, arthritis, periodontal disease, osteogenesis imperfecta, and diseases of the central nervous system. MMPs participate in the occurrence and development of numerous cancers and are closely related to immunity. In the present study, we review the immunomodulatory role of MMPs in colitis-associated cancer (CAC) and discuss relevant clinical applications. We analyze more than 300 pharmacological studies retrieved from PubMed and the Web of Science, related to MMPs, cancer, colitis, CAC, and immunomodulation. Key MMPs that interfere with pathological processes in CAC such as MMP-2, MMP-3, MMP-7, MMP-9, MMP-10, MMP-12, and MMP-13, as well as their corresponding mechanisms are elaborated. MMPs are involved in cell proliferation, cell differentiation, angiogenesis, ECM remodeling, and the inflammatory response in CAC. They also affect the immune system by modulating differentiation and immune activity of immune cells, recruitment of macrophages, and recruitment of neutrophils. Herein we describe the immunomodulatory role of MMPs in CAC to facilitate treatment of this special type of colon cancer, which is preceded by detectable inflammatory bowel disease in clinical populations.

Impact of liver fibrosis and nodules formation on hemodynamics in young adults after total cavopulmonary connection. A magnetic resonance study

Background

The aim of this study was to analyze the relation between the hepatic fibrosis markers, liver morphology and hemodynamics assessed by magnetic resonance imaging (MRI) after total cavopulmonary connection (TCPC).

Materials and methods

Adult patients after TCPC performed in childhood between 1993 and 2003 are the subjects of this observational study. The follow-up protocol consisted of clinical and echocardiographic examination, liver elastography, cardiopulmonary exercise test, MRI hemodynamics and liver morphology assessment and direct enhanced liver fibrosis (ELF) test.

Results

The cohort consisted of 39 patients (46% female) with a median age at study 26 (IQR 23–28) years and interval from TCPC 21 (IQR 20–23) years. There was no correlation between ELF test and any MRI variables, but procollagen III amino-terminal peptide (PIIINP), a single component of ELF test, correlated significantly with ventricular end-diastolic volume (r = 0.33; p = 0.042) and inferior vena cava flow (r = 0.47; p = 0.003). Fifteen (38%) patients with liver nodules had compared to other 24 patients higher end-diastolic volume (ml/m²) 102.8 ± 20.0 vs. 88.2 ± 17.7; p = 0.023, respectively. PIIINP correlated significantly with inferior vena cava flow (r = 0.56; p = 0.030) and with end-diastolic volume (r = 0.53; p = 0.043), but only in patients with liver nodules.

Conclusion

Gradual progression of liver fibrosis, particularly hepatic arterialization caused by liver nodules formation, increases inferior vena cava flow and subsequent ventricular volume overload may further compromise single ventricle functional reserve in adult patients after TCPC.

Roles of Epigenetics in Cardiac Fibroblast Activation and Fibrosis

Cardiac fibrosis is a common pathophysiologic process associated with numerous cardiovascular diseases, resulting in cardiac dysfunction. Cardiac fibroblasts (CFs) play an important role in the production of the extracellular matrix and are the essential cell type in a quiescent state in a healthy heart. In response to diverse pathologic stress and environmental stress, resident CFs convert to activated fibroblasts, referred to as myofibroblasts, which produce more extracellular matrix, contributing to cardiac fibrosis. Although multiple molecular mechanisms are implicated in CFs activation and cardiac fibrosis, there is increasing evidence that epigenetic regulation plays a key role in this process. Epigenetics is a rapidly growing field in biology, and provides a modulated link between pathological stimuli and gene expression profiles, ultimately leading to corresponding pathological changes. Epigenetic modifications are mainly composed of three main categories: DNA methylation, histone modifications, and non-coding RNAs. This review focuses on recent advances regarding epigenetic regulation in cardiac fibrosis and highlights the effects of epigenetic modifications on CFs activation. Finally, we provide some perspectives and prospects for the study of epigenetic modifications and cardiac fibrosis.

The Atrium in Atrial Fibrillation - A Clinical Review on How to Manage Atrial Fibrotic Substrates

Atrial fibrillation (AF) is the most common sustained arrhythmia in the population and is associated with a significant clinical and economic burden. Rigorous assessment of the presence and degree of an atrial arrhythmic substrate is essential for determining treatment options, predicting long-term success after catheter ablation, and as a substrate critical in the pathophysiology of atrial thrombogenesis. Catheter ablation of AF has developed into an essential rhythm-control strategy. Nowadays is one of the most common cardiac ablation procedures performed worldwide, with its success inversely related to the extent of atrial structural disease. Although atrial substrate evaluation remains complex, several diagnostic resources allow for a more comprehensive assessment and quantification of the extent of left atrial structural remodeling and the presence of atrial fibrosis. In this review, we summarize the current knowledge on the pathophysiology, etiology, and electrophysiological aspects of atrial substrates promoting the development of AF. We also describe the risk factors for its development and how to diagnose its presence using imaging, electrocardiograms, and electroanatomic voltage mapping. Finally, we discuss recent data regarding fibrosis biomarkers that could help diagnose atrial fibrotic substrates.

Comparison of serum biomarkers of myocardial fibrosis with cardiac magnetic resonance in patients operated for tetralogy of Fallot

BACKGROUND

Serum biomarkers of myocardial fibrosis are considered markers of adverse outcome in adults with heart disease. Associations between biomarkers and clinical parameters in tetralogy of Fallot (TOF) has been understudied. We compared serum biomarker profiles with clinical and cardiac magnetic resonance (CMR) parameters of ventricular remodeling in patients with repaired TOF.

METHODS

Serum biomarkers [metalloproteinases MMP1 and MMP9, galectin-3, micro-RNA21 (miR21)), ST2, procollagen type I carboxy-terminal propeptide (PICP), and NTproBNP] were measured in TOF patients undergoing CMR. Associations between biomarkers and clinical and CMR variables were assessed using correlation coefficients, and linear and logistic regression.

RESULTS

Sixty patients were investigated, of which 47% were male. Age at CMR and TOF repair was 15 years [interquartile range (IQR) 9, 22] and 3.2 months (IQR 0.8, 6.2), respectively. Twelve (20%) had prior pulmonary valve replacement (PVR). MMP1 values were higher among those with prior PVR (16.7 (IQR 7.9, 25.5) vs 14.4 (IQR 9.9, 24.9), p = 0.02). When stratifying MMP1 into low and high groups, higher MMP1 was associated with higher indexed right (RV) and left ventricular (LV) mass and RV mass:volume ratios after adjusting for PVR. No other associations between biomarkers and CMR parameters were identified.

CONCLUSIONS

Only MMP1 was associated with markers of RV remodeling after TOF repair. As an enzyme involved in extracellular matrix degradation, MMP1 could be associated with fibrotic processes underlying RV remodeling, including dilation and hypertrophy. The additional biomarkers may not be specific towards cardiac remodeling. These findings merit further correlations with myocardial fibrosis measurements by CMR.

The association between markers of type I collagen synthesis and echocardiographic response to spironolactone in patients at risk of heart failure: findings from the HOMAGE trial

BACKGROUND

Procollagen type I C-terminal propeptide (PICP) and procollagen type III N-terminal propeptide (PIIINP) are markers reflecting collagen synthesis in cardiac fibrosis. However, they may be influenced by the presence of noncardiac comorbidities (e.g., ageing, obesity, renal impairment). Understanding the associations between markers of collagen synthesis and abnormalities of cardiac structure and function is important to screen for myocardial fibrosis and monitor the antifibrotic effect of medications.

METHODS

The HOMAGE (Heart OMics in Aging) trial showed that spironolactone decreased serum PICP concentrations and improved cardiac remodeling over 9 months in a population at risk of developing heart failure (HF). We evaluated the associations between echocardiographic variables, PICP, PIIINP and galectin-3 at baseline and during the course of the trial.

RESULTS

Among 527 individuals (74±7years, 26% women), median serum concentrations of PICP, PIIINP and galectin-3 were 80.6μg/L (65.1-97.0), 3.9μg/L (3.1-5.0) and 16.1μg/L (13.5-19.7), respectively. After adjustment for potential confounders, higher serum PICP was significantly associated with left ventricular hypertrophy, left atrial enlargement, and greater ventricular stiffness (all p-values<0.05), whereas serum PIIINP and galectin-3 were not (all p-values>0.05). In patients treated with spironolactone, a reduction in serum PICP during the trial was associated with a decrease in E/e' (adjusted-beta [95% CI] =0.93 [0.14-1.73]; p=0.022).

CONCLUSIONS

In individuals at high risk of developing HF, serum PICP was associated with cardiac structural and functional abnormalities, and a decrease in PICP with spironolactone was correlated with improved diastolic dysfunction as assessed by E/e'. In contrast, no such associations were present for serum PIIINP and galectin-3.

Clinical Phenotypes of Heart Failure With Preserved Ejection Fraction to Select Preclinical Animal Models

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To better define HFpEF clinically, patients are nowadays often clustered into phenogroups, based on their comorbidities and symptoms

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Many animal models claim to mimic HFpEF, but phenogroups are not yet regularly used to cluster them

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HFpEF animals models often lack reports of clinical symptoms of HF, therefore mainly presenting as extended models of LVDD, clinically seen as a prestate of HFpEF

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We investigated if clinically relevant phenogroups can guide selection of animal models aiming at better defined animal research

At least one-half of the growing heart failure population consists of heart failure with preserved ejection fraction (HFpEF). The limited therapeutic options, the complexity of the syndrome, and many related comorbidities emphasize the need for adequate experimental animal models to study the etiology of HFpEF, as well as its comorbidities and pathophysiological changes. The strengths and weaknesses of available animal models have been reviewed extensively with the general consensus that a “1-size-fits-all” model does not exist, because no uniform HFpEF patient exists. In fact, HFpEF patients have been categorized into HFpEF phenogroups based on comorbidities and symptoms. In this review, we therefore study which animal model is best suited to study the different phenogroups—to improve model selection and refinement of animal research. Based on the published data, we extrapolated human HFpEF phenogroups into 3 animal phenogroups (containing small and large animals) based on reports and definitions of the authors: animal models with high (cardiac) age (phenogroup aging); animal models focusing on hypertension and kidney dysfunction (phenogroup hypertension/kidney failure); and models with hypertension, obesity, and type 2 diabetes mellitus (phenogroup cardiometabolic syndrome). We subsequently evaluated characteristics of HFpEF, such as left ventricular diastolic dysfunction parameters, systemic inflammation, cardiac fibrosis, and sex-specificity in the different models. Finally, we scored these parameters concluded how to best apply these models. Based on our findings, we propose an easy-to-use classification for future animal research based on clinical phenogroups of interest.

The Cardiomyocyte in Heart Failure with Preserved Ejection Fraction-Victim of Its Environment?

Heart failure (HF) with preserved left ventricular ejection fraction (HFpEF) is becoming the predominant form of HF. However, medical therapy that improves cardiovascular outcome in HF patients with almost normal and normal systolic left ventricular function, but diastolic dysfunction is missing. The cause of this unmet need is incomplete understanding of HFpEF pathophysiology, the heterogeneity of the patient population, and poor matching of therapeutic mechanisms and primary pathophysiological processes. Recently, animal models improved understanding of the pathophysiological role of highly prevalent and often concomitantly presenting comorbidity in HFpEF patients. Evidence from these animal models provide first insight into cellular pathophysiology not considered so far in HFpEF disease, promising that improved understanding may provide new therapeutical targets. This review merges observation from animal models and human HFpEF disease with the intention to converge cardiomyocytes pathophysiological aspects and clinical knowledge.

Exploring the Correlation Between Fibrosis Biomarkers and Clinical Disease Severity in PLN p.Arg14del Patients

Background: Pathogenic variants in phospholamban (PLN, like p. Arg14del), are found in patients diagnosed with arrhythmogenic (ACM) and dilated cardiomyopathy (DCM). Fibrosis formation in the heart is one of the hallmarks in PLN p.Arg14del carriers. During collagen synthesis and breakdown, propeptides are released into the circulation, such as procollagen type I carboxy-terminal propeptide (PICP) and C-terminal telopeptide collagen type I (ICTP).

Aim: To investigate if PICP/ICTP levels in blood are correlative biomarkers for clinical disease severity and outcome in PLN p.Arg14del variant carriers.

Methods: Serum and EDTA blood samples were collected from 72 PLN p.Arg14del carriers (age 50.5 years, 63% female) diagnosed with ACM (n = 12), DCM (n = 14), and preclinical variant carriers (n = 46). PICP levels were measured with an enzyme-linked immune sorbent assay and ICTP with a radio immuno-assay. Increased PICP/ICTP ratios suggest a higher collagen deposition. Clinical data including electrocardiographic, and imaging results were adjudicated from medical records.

Results: No correlation between PICP/ICTP ratios and late gadolinium enhancement (LGE) was found. Moderate correlations were found between the PICP/ICTP ratio and end-diastolic/systolic volume (both rs = 0.40, n = 23, p = 0.06). PICP/ICTP ratio was significantly higher in patients with T wave inversion (TWI), especially in leads V4–V6, II, III, and aVF (p &lt; 0.022) and in patients with premature ventricular contractions (PVCs) during an exercise tolerance test (p = 0.007).

Conclusion: High PICP/ICTP ratios correlated with clinical parameters, such as TWI and PVCs. Given the limited size and heterogeneity of the patient group, additional studies are required to substantiate the incremental prognostic value of these fibrosis biomarkers in PLN p.Arg14del patients.

Myocardial fibrosis in congenital heart disease

Myocardial fibrosis resulting from the excessive deposition of collagen fibers through the myocardium is a common histopathologic finding in a wide range of cardiovascular diseases, including congenital anomalies. Interstitial fibrosis has been identified as a major cause of myocardial dysfunction since it distorts the normal architecture of the myocardium and impairs the biological function and properties of the interstitium. This review summarizes current knowledge on the mechanisms and detrimental consequences of myocardial fibrosis in heart failure and arrhythmias, discusses the usefulness of available imaging techniques and circulating biomarkers to assess this entity and reviews the current body of evidence regarding myocardial fibrosis in the different subsets of congenital heart diseases with implications in research and treatment.

Cardiac fibrosis and atrial fibrillation

Cardiac fibrosis is characterized by the imbalance of production and degradation of the extracellular matrix. The result of this process is an accumulation of scar tissue, which is associated with many pathological processes such as excessive mechanical stress on the heart, inflammation, ischemia, oxidative stress, or excessive neurohormonal activation. Fibrotic response results in damaged heart architecture and dysfunction of the heart. Cardiac fibrosis leads to increased stiffness of the left ventricle and arteries, promotes disorders of contraction and relaxation of the heart, disrupts electrophysiology of heart cells, and induces arrhythmias.

Atrial fibrillation is one of the most common arrhythmias. It is associated with a deterioration in the quality of life and more frequent use of medical assistance. It is also an instantaneous risk factor for many diseases, including stroke. The underlying cause of this arrhythmia is electrical and structural remodeling induced by cardiac fibrosis. Therefore, much attention is paid to the search for biochemical markers that would allow non-invasive determination of the degree of this fibrosis.

The promising markers include galectin-3, human epididymis protein 4 (HE4), serum soluble ST2, and adipose triglyceride lipase (ATGL). Studies have shown that plasma concentrations of these substances reflect the degree of myocardial fibrosis and are indirectly associated with AF.

There are high hopes for the use of these markers in patients undergoing arrhythmia ablation. More research is needed to confirm that these markers can be used to estimate the chance of maintaining sinus rhythm in patients after ablation.

Valsartan in early-stage hypertrophic cardiomyopathy: a randomized phase 2 trial

Hypertrophic cardiomyopathy (HCM) is often caused by pathogenic variants in sarcomeric genes and characterized by left ventricular (LV) hypertrophy, myocardial fibrosis and increased risk of heart failure and arrhythmias. There are no existing therapies to modify disease progression. In this study, we conducted a multi-center, double-blind, placebo-controlled phase 2 clinical trial to assess the safety and efficacy of the angiotensin II receptor blocker valsartan in attenuating disease evolution in early HCM. In total, 178 participants with early-stage sarcomeric HCM were randomized (1:1) to receive valsartan (320 mg daily in adults; 80-160 mg daily in children) or placebo for 2 years ( NCT01912534 ). Standardized changes from baseline to year 2 in LV wall thickness, mass and volumes; left atrial volume; tissue Doppler diastolic and systolic velocities; and serum levels of high-sensitivity troponin T and N-terminal pro-B-type natriuretic protein were integrated into a single composite z-score as the primary outcome. Valsartan (n = 88) improved cardiac structure and function compared to placebo (n = 90), as reflected by an increase in the composite z-score (between-group difference +0.231, 95% confidence interval (+0.098, +0.364); P = 0.001), which met the primary endpoint of the study. Treatment was well-tolerated. These results indicate a key opportunity to attenuate disease progression in early-stage sarcomeric HCM with an accessible and safe medication.

The role of brain natriuretic peptide in atrial fibrillation: a substudy of the Substrate Modification with Aggressive Blood Pressure Control for Atrial Fibrillation (SMAC-AF) trial

BACKGROUND

Catheter ablation is an established therapy for atrial fibrillation but is limited by recurrence; efforts have been made to identify biomarkers that predict recurrence. We investigated the effect of baseline NT-proBNP on AF recurrence following catheter ablation in patients randomized to aggressive (< 120/80 mmHg) or standard blood pressure management (< 140/90 mmHg) in the Substrate Modification with Aggressive Blood Pressure Control trial (SMAC-AF).

METHODS

The SMAC-AF study included 173 patients resistant or intolerant to at least one class I or III antiarrhythmic drug. We studied the effect of baseline NT-proBNP on the primary outcome of AF recurrence > 3 months post-ablation.

RESULTS

Of the 173 patients, 88 were randomized to the aggressive cohort, and 85 into the standard group. The primary outcome occurred in 61.4% of those in the aggressive arm, versus 61.2% in the standard arm. In the aggressive group, logNT-proBNP predicted recurrence (HR 1.28, p = 0.04, adjusted HR 1.43, p = 0.03), while in the standard cohort, it did not (HR 0.94, p = 0.62, adjusted HR 0.83, p = 0.22). NT-proBNP ≥ 280 pg/mL also predicted occurrence in the aggressive (HR 1.98, p = 0.02) but not the standard cohort (HR 1.00, p = 1.00).

CONCLUSION

We conclude that pre-ablation NT-proBNP may be useful in predicting recurrence in hypertensive patients and identifying patients who benefit from aggressive blood control and upstream therapies.

TRIAL REGISTRATION

NCT00438113, registered February 21, 2007.

Exploring Functional Differences between the Right and Left Ventricles to Better Understand Right Ventricular Dysfunction

The right and left ventricles have traditionally been studied as individual entities. Furthermore, modifications found in diseased left ventricles are assumed to influence on right ventricle alterations, but the connection is poorly understood. In this review, we describe the differences between ventricles under physiological and pathological conditions. Understanding the mechanisms that differentiate both ventricles would facilitate a more effective use of therapeutics and broaden our knowledge of right ventricle (RV) dysfunction. RV failure is the strongest predictor of mortality in pulmonary arterial hypertension, but at present, there are no definitive therapies directly targeting RV failure. We further explore the current state of drugs and molecules that improve RV failure in experimental therapeutics and clinical trials to treat pulmonary arterial hypertension and provide evidence of their potential benefits in heart failure.

Mechanisms of reducing joint stiffness by blocking collagen fibrillogenesis in a rabbit model of posttraumatic arthrofibrosis

Posttraumatic fibrotic scarring is a significant medical problem that alters the proper functioning of injured tissues. Current methods to reduce posttraumatic fibrosis rely on anti-inflammatory and anti-proliferative agents with broad intracellular targets. As a result, their use is not fully effective and may cause unwanted side effects. Our group previously demonstrated that extracellular collagen fibrillogenesis is a valid and specific target to reduce collagen-rich scar buildup. Our previous studies showed that a rationally designed antibody that binds the C-terminal telopeptide of the α2(I) chain involved in the aggregation of collagen molecules limits fibril assembly in vitro and reduces scar formation in vivo. Here, we have utilized a clinically relevant arthrofibrosis model to study the broad mechanisms of the anti-scarring activity of this antibody. Moreover, we analyzed the effects of targeting collagen fibril formation on the quality of healed joint tissues, including the posterior capsule, patellar tendon, and subchondral bone. Our results show that blocking collagen fibrillogenesis not only reduces collagen content in the scar, but also accelerates the remodeling of healing tissues and changes the collagen fibrils’ cross-linking. In total, this study demonstrated that targeting collagen fibrillogenesis to limit arthrofibrosis affects neither the quality of healing of the joint tissues nor disturbs vital tissues and organs.

The combination of carboxy-terminal propeptide of procollagen type I blood levels and late gadolinium enhancement at cardiac magnetic resonance provides additional prognostic information in idiopathic dilated cardiomyopathy - A multilevel assessment of myocardial fibrosis in dilated cardiomyopathy

Aims

To determine the prognostic value of multilevel assessment of fibrosis in dilated cardiomyopathy (DCM) patients.

Methods and results

We quantified fibrosis in 209 DCM patients at three levels: (i) non‐invasive late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR); (ii) blood biomarkers [amino‐terminal propeptide of procollagen type III (PIIINP) and carboxy‐terminal propeptide of procollagen type I (PICP)], (iii) invasive endomyocardial biopsy (EMB) (collagen volume fraction, CVF). Both LGE and elevated blood PICP levels, but neither PIIINP nor CVF predicted a worse outcome defined as death, heart transplantation, heart failure hospitalization, or life‐threatening arrhythmias, after adjusting for known clinical predictors [adjusted hazard ratios: LGE 3.54, 95% confidence interval (CI) 1.90–6.60; P < 0.001 and PICP 1.02, 95% CI 1.01–1.03; P = 0.001]. The combination of LGE and PICP provided the highest prognostic benefit in prediction (likelihood ratio test P = 0.007) and reclassification (net reclassification index: 0.28, P = 0.02; and integrated discrimination improvement index: 0.139, P = 0.01) when added to the clinical prediction model. Moreover, patients with a combination of LGE and elevated PICP (LGE+/PICP+) had the worst prognosis (log‐rank P < 0.001). RNA‐sequencing and gene enrichment analysis of EMB showed an increased expression of pro‐fibrotic and pro‐inflammatory pathways in patients with high levels of fibrosis (LGE+/PICP+) compared to patients with low levels of fibrosis (LGE‐/PICP‐). This would suggest the validity of myocardial fibrosis detection by LGE and PICP, as the subsequent generated fibrotic risk profiles are associated with distinct cardiac transcriptomic profiles.

Conclusion

The combination of myocardial fibrosis at CMR and circulating PICP levels provides additive prognostic value accompanied by a pro‐fibrotic and pro‐inflammatory transcriptomic profile in DCM patients with LGE and elevated PICP.

Prognostic significance of liver stiffness assessed by fibrosis-4 index in patients with heart failure

BACKGROUND

Heart failure (HF)-related congestive hepatopathy is a well-recognized problem in management of HF. The fibrosis-4 (FIB4) index calculated by [age × aspartate aminotransferase (IU/L)/platelet count (10⁹ /L) × square root of alanine aminotransferase (IU/L)] is useful for evaluating liver stiffness. We aimed to investigate the impact of the FIB4 index on prognosis in patients with HF.

METHODS AND RESULTS

Consecutive HF patients referred for hospitalization at Kumamoto University Hospital, Japan, were registered between 2006 and 2015. We observed cardiovascular outcomes in each type of HF [HF with reduced left ventricular ejection fraction (LVEF) (HFrEF), HF with mid-range LVEF (HFmrEF) and with preserved LVEF (HFpEF)] according to their FIB4 index; Group 1 (FIB4 index <1.3), Group 2 (FIB4 index: 1.3-2.67), and Group 3 (FIB4 index >2.67). This study enrolled 83 HFrEF patients, 117 HFmrEF patients, and 504 HFpEF patients. In HFpEF patients, the Kaplan-Meier curve revealed that Group 3 had a significantly higher rate of total cardiovascular events compared with the other two groups. By contrast, the occurrences of total cardiovascular events were not different among three groups in HFrEF and HFmrEF patients. Multivariate Cox proportional hazard analysis with significant factors in univariate analysis identified that the FIB4 index as an independent and significant predictor for future total cardiovascular events in HFpEF patients (hazard ratio: 1.09, 95% confidence interval: 1.03-1.15, P = 0.001).

CONCLUSIONS

The FIB4 index was a significant predictor for total cardiovascular events in HFpEF.

Assessment of subclinical left ventricular dysfunction with speckle-tracking echocardiography in hyperthyroid and euthyroid Graves' disease and its correlation with serum TIMP-1

BACKGROUND

Graves' disease has a multitude of effects on the cardiovascular system. In the detection of subclinical left ventricular dysfunction, speckle-tracking echocardiography is more useful than conventional echocardiography. The aim of the present study was to compare the longitudinal global strain values and venous blood concentration of (tissue inhibitor of metalloproteinase-1) TIMP-1, a regulator of the extracellular matrix, among hyperthyroid patients with Graves' disease, euthyroid patients with Graves' disease and healthy control subjects.

MATERIALS AND METHODS

The study enrolled 40 hyperthyroid patients with newly diagnosed Graves' disease, 40 patients with Graves' disease who were euthyroid for at least 6 months and 40 control subjects with normal thyroid function. Participants underwent conventional echocardiography and speckle-tracking echocardiography to obtain segmental and global longitudinal strain values. In addition, the serum TIMP-1 value was assessed in the venous blood samples of the participants.

RESULTS

The hyperthyroid Graves' patients showed greater serum TIMP-1 levels versus the control group and the euthyroid Graves' group. Compared to the control group, the TIMP-1 level was also significantly higher in the euthyroid Graves' group. Lower GLS (global longitudinal strain) average and GLS2C, GLS3C, GLS4C values were observed in both the hyperthyroid and euthyroid Graves' patients compared to the control group. The euthyroid Graves' patients and hyperthyroid Graves' patients had similar GLS values. The serum TIMP-1 level was negatively correlated with global strain values.

CONCLUSION

Graves' disease coexists with impaired segmental and global longitudinal strain and increased TIMP-1 levels. This coexistence seems to be independent of serum thyroid hormone levels.

Diffuse myocardial fibrosis: mechanisms, diagnosis and therapeutic approaches

Diffuse myocardial fibrosis resulting from the excessive deposition of collagen fibres through the entire myocardium is encountered in a number of chronic cardiac diseases. This lesion results from alterations in the regulation of fibrillary collagen turnover by fibroblasts, facilitating the excessive deposition of type I and type III collagen fibres within the myocardial interstitium and around intramyocardial vessels. The available evidence suggests that, beyond the extent of fibrous deposits, collagen composition and the physicochemical properties of the fibres are also relevant in the detrimental effects of diffuse myocardial fibrosis on cardiac function and clinical outcomes in patients with heart failure. In this regard, findings from the past 20 years suggest that various clinicopathological phenotypes of diffuse myocardial fibrosis exist in patients with heart failure. In this Review, we summarize the current knowledge on the mechanisms and detrimental consequences of diffuse myocardial fibrosis in heart failure. Furthermore, we discuss the validity and usefulness of available imaging techniques and circulating biomarkers to assess the clinicopathological variation in this lesion and to track its clinical evolution. Finally, we highlight the currently available and potential future therapeutic strategies aimed at personalizing the prevention and reversal of diffuse myocardial fibrosis in patients with heart failure.

Myocardial fibrosis in patients with a history of Kawasaki disease

Objectives

Cardiac magnetic resonance (CMR) measurements of myocardial extracellular volume fraction (ECV) and late gadolinium enhancement (LGE) in patients with a history of Kawasaki disease (KD) were analyzed to determine whether fibrosis was increased compared to controls.

Methods

In this single center retrospective study, patients with KD who had a CMR with ECV measurement and LGE assessment were included. The ECV was calculated in the mid-left ventricle by measuring T1 values for blood pool and myocardium before and after gadolinium administration with a Look-Locker technique. CMR findings were compared to 20 control subjects.

Results

KD patients (n = 13) had a median age at CMR of 14.9 years (range, 7.5-36.0). Control subjects (n = 20) had a median age at CMR of 16 years (range, 11.0-36.0). Twelve KD patients had coronary aneurysms. The KD patients had a significantly lower indexed LV mass (p = 0.03) and LV mass/volume ratio (p = 0.01). ECV was not significantly different in KD patients and controls (0.26 (range, 0.20-0.30) vs. 0.25 (range, 0.18-0.28), p = 0.28). One KD patient (8%) had an increased (>0.28) ECV. LGE indicating focal fibrosis was found in 5 of 13 (38%) of KD patients. Patients with LGE tended to have a higher maximum coronary dimension z-score (p = 0.09).

Conclusions

In this study of KD patients, most of whom had aneurysms, ECV did not differ significantly from that in normal controls. Focal fibrosis based on LGE was common. Future larger studies should compare ECV in KD patients with and without aneurysms to define the risk of myocardial fibrosis after KD.

Association between insulin resistance and left ventricular hypertrophy in asymptomatic, Black, sub-Saharan African, hypertensive patients: a case-control study

Background

Conflicting information exists regarding the association between insulin resistance (IR) and left ventricular hypertrophy (LVH). We described the associations between obesity, fasting insulinemia, homeostasis model assessment of insulin resistance (HOMA-IR), and LVH in Black patients with essential hypertension.

Methods

A case–control study was conducted at the Centre Médical de Kinshasa (CMK), the Democratic Republic of the Congo, between January and December 2019. Cases and controls were hypertensive patients with and without LVH, respectively. The relationships between obesity indices, physical inactivity, glucose metabolism and lipid disorder parameters, and LVH were assessed using linear and logistic regression analyses in simple and univariate exploratory analyses, respectively. When differences were observed between LVH and independent variables, the effects of potential confounders were studied through the use of multiple linear regression and in conditional logistic regression in multivariate analyses. The coefficients of determination (R²), adjusted odds ratios (aORs), and their 95% confidence intervals (95% CIs) were calculated to determine associations between LVH and the independent variables.

Results

Eighty-eight LVH cases (52 men) were compared against 132 controls (81 men). Variation in left ventricular mass (LVM) could be predicted by the following variables: age (19%), duration of hypertension (31.3%), body mass index (BMI, 44.4%), waist circumference (WC, 42.5%), glycemia (20%), insulinemia (44.8%), and HOMA-IR (43.7%). Hypertension duration, BMI, insulinemia, and HOMA-IR explained 68.3% of LVM variability in the multiple linear regression analysis. In the logistic regression model, obesity increased the risk of LVH by threefold [aOR 2.8; 95% CI (1.06–7.4); p = 0.038], and IR increased the risk of LVH by eightfold [aOR 8.4; 95 (3.7–15.7); p < 0.001].

Conclusion

Obesity and IR appear to be the primary predictors of LVH in Black sub-Saharan African hypertensive patients. The comprehensive management of cardiovascular risk factors should be emphasized, with particular attention paid to obesity and IR. A prospective population-based study of Black sub-Saharan individuals that includes the use of serial imaging remains essential to better understand subclinical LV deterioration over time and to confirm the role played by IR in Black sub-Saharan individuals with hypertension.

Galectin-3 Inhibition With Modified Citrus Pectin in Hypertension

We investigated the effect of galectin-3 (Gal-3) inhibition with modified citrus pectin on markers of collagen metabolism in a proof-of-concept randomized placebo-controlled trial of participants with elevated Gal-3 levels and hypertension. Although higher Gal-3 levels were associated with female sex, diabetes, and reduced glomerular filtration rate in cross-sectional analyses, treatment with modified citrus pectin did not change collagen markers. The effect of Gal-3 inhibition among individuals with heart failure warrants further investigation.

Cardiac fibrosis

Myocardial fibrosis, the expansion of the cardiac interstitium through deposition of extracellular matrix proteins, is a common pathophysiologic companion of many different myocardial conditions. Fibrosis may reflect activation of reparative or maladaptive processes. Activated fibroblasts and myofibroblasts are the central cellular effectors in cardiac fibrosis, serving as the main source of matrix proteins. Immune cells, vascular cells and cardiomyocytes may also acquire a fibrogenic phenotype under conditions of stress, activating fibroblast populations. Fibrogenic growth factors (such as transforming growth factor-β and platelet-derived growth factors), cytokines [including tumour necrosis factor-α, interleukin (IL)-1, IL-6, IL-10, and IL-4], and neurohumoral pathways trigger fibrogenic signalling cascades through binding to surface receptors, and activation of downstream signalling cascades. In addition, matricellular macromolecules are deposited in the remodelling myocardium and regulate matrix assembly, while modulating signal transduction cascades and protease or growth factor activity. Cardiac fibroblasts can also sense mechanical stress through mechanosensitive receptors, ion channels and integrins, activating intracellular fibrogenic cascades that contribute to fibrosis in response to pressure overload. Although subpopulations of fibroblast-like cells may exert important protective actions in both reparative and interstitial/perivascular fibrosis, ultimately fibrotic changes perturb systolic and diastolic function, and may play an important role in the pathogenesis of arrhythmias. This review article discusses the molecular mechanisms involved in the pathogenesis of cardiac fibrosis in various myocardial diseases, including myocardial infarction, heart failure with reduced or preserved ejection fraction, genetic cardiomyopathies, and diabetic heart disease. Development of fibrosis-targeting therapies for patients with myocardial diseases will require not only understanding of the functional pluralism of cardiac fibroblasts and dissection of the molecular basis for fibrotic remodelling, but also appreciation of the pathophysiologic heterogeneity of fibrosis-associated myocardial disease.

Biomarker of Collagen Turnover (C-Terminal Telopeptide) and Prognosis in Patients With Non- ST -Elevation Acute Coronary Syndromes

Background

Small studies have suggested an association between markers of collagen turnover and adverse outcomes in heart failure (HF). We examined C‐terminal telopeptide (beta‐CTx) and the risk of cardiovascular death or new or worsening HF in non–ST‐elevation acute coronary syndrome.

Methods and Results

We measured baseline serum beta‐CTx, NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), hsTnT (high‐sensitivity cardiac troponin T) and hsCRP (high‐sensitivity C‐reactive protein) (Roche Diagnostics) in a nested biomarker analysis (n=4094) from a study of patients with non–ST‐elevation acute coronary syndrome. The relationship between quartiles of beta‐CTx and cardiovascular death or HF over a median follow‐up time of 12 months was analyzed using adjusted Cox models. Higher beta‐CTx levels identified a significantly higher risk of cardiovascular death/HF (Q4 10.9% versus Q1 3.8%, Logrank P<0.001). After multivariable adjustment, beta‐CTx in the top quartile (Q4) was associated with cardiovascular death/HF (Q4 versus Q1: adjusted hazard ratio 2.22 [1.50–3.27]) and its components (Q4 versus Q1: cardiovascular death: adjusted hazard ratio 2.48 [1.46–4.21]; HF: adjusted hazard ratio 2.04 [1.26–3.30]). In an adjusted multimarker model including NT‐proBNP, hsTnT, and hsCRP, beta‐CTx remained independently associated with cardiovascular death/HF (Q4 versus Q1: adjusted hazard ratio 1.98 [1.34–2.93]) and its components. Beta‐CTx correlated weakly with NT‐proBNP (r=0.17, P<0.001) and left ventricular ejection fraction (r=−0.05, P=0.008) and did not correlate with hsTnT (r=0.02, P=0.20), or hsCRP (r=−0.03, P=0.09).

Conclusions

Levels of beta‐CTx, a biomarker of collagen turnover, were associated with cardiovascular death and HF in patients with non–ST‐elevation acute coronary syndrome. This biomarker, which correlated only weakly or not significantly with traditional biomarkers of cardiovascular death and HF, may provide complementary pathobiological insight and risk stratification in these patients.

Matrix Metalloproteinases Increase Because of Hypoperfusion in Obstructive Hypertrophic Cardiomyopathy

BACKGROUND

Myocardial fibrosis (MF) is considered a result of microvascular dysfunction in patients with hypertrophic cardiomyopathy. Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), capable of degrading collagen, directly participate in the development of MF. First we investigated the relationships among MF, microvascular rarefaction, and MMPs. Then we assessed the prognostic value of MF-related circulating biomarkers.

METHODS

Fifty-five obstructive hypertrophic cardiomyopathy (HOCM) patients were enrolled after surgical myectomy. Myocardial samples were performed with Masson's trichrome staining and immunohistochemical procedures for collagen volume fraction and microvascular density, respectively. Enzyme-linked immunosorbent assays were used to assess myocardial and plasma of MMP-2, MMP-9, and TIMP-1 and plasma C-terminal propeptide of procollagen type Ⅰ (PICP) and C-terminal telopeptide of type Ⅰ collagen (ICTP) levels. The composite cardiovascular endpoint consisted of new-onset atrial fibrillation, heart failure requiring hospitalization, and all-cause death.

RESULTS

In HOCM patients microvascular density was associated with the myocardial MMP-2/TIMP-1 ratio (r = -0.348, P = .009), whereas no correlation was found between collagen volume fraction and myocardial MMPs. During the 44-month follow-up 6 patients experienced a cardiovascular endpoint. The plasma PICP/ICTP ratio and MMP-2/TIMP-1 ratio were the 2 strongest prognostic makers. In multivariable analyses high PICP/ICTP and MMP-2/TIMP-1 ratios remained independent predictors of cardiovascular outcomes after adjusting for clinical confounders (hazard ratios, 12.683 [P = .021] and 17.037 [P = .027], respectively).

CONCLUSIONS

In HOCM patients the myocardial MMP-2/TIMP-1 ratio was elevated because of microvascular rarefaction but may not be responsible for MF. High plasma PICP/ICTP and MMP-2/TIMP-1 ratios are independent predictors of adverse outcomes in HOCM patients.

Si-Miao-Yong-An decoction attenuates cardiac fibrosis via suppressing TGF-β1 pathway and interfering with MMP-TIMPs expression

BACKGROUND

Myocardial fibrosis is an important pathological feature of pressure overload cardiac remodeling. Si-Miao-Yong-An decoction (SMYAD), a traditional Chinese formula, is now clinically used in the treatment of cardiovascular diseases in China. However, its mechanisms in the prevention of heart failure are not fully revealed.

PURPOSE

To determine whether treatment with SMYAD for 4 weeks would lead to changes in collagen metabolism and ventricular remodeling in a mice model of heart failure.

METHODS

Mice were subjected to transverse aorta constriction to generate pressure overload induced cardiac remodeling and then were administered SMYAD (14.85 g/kg/day) or captopril (16.5 mg/kg/day) intragastrically for 4 weeks after surgery. Echocardiography and immunohistochemical examination were used to evaluate the effects of SMYAD. The mRNA of collagen metabolism biomarkers were detected. Protein expression of TGF-β1/Smad and TGF-β1/TAK1/p38 pathway were assessed by Western blot.

RESULTS

SMYAD significantly improved cardiac function, increased left ventricle ejection fraction, and decreased fibrosis area and αSMA expression. Moreover, SMYAD reduced proteins expression related to collagen metabolism, including Col1, Col3, TIMP2 and CTGF. The increased levels of TGF-β1, Smad2, and Smad3 phosphorylation were attenuated in SMYAD group. In addition, SMYAD reduced the levels of TGF-β1, p-TAK1 and p-p38 compared with TAC group.

CONCLUSIONS

SMYAD improved cardiac fibrosis and heart failure by inhibition of TGF-β1/Smad and TGF-β1/TAK1/p38 pathway. SMYAD protected against cardiac fibrosis and maintained collagen metabolism balance by regulating MMP-TIMP expression. Taken together, these results indicate that SMYAD might be a promising therapeutic agent against cardiac fibrosis.

Inhibition of histone demethylase JMJD1C attenuates cardiac hypertrophy and fibrosis induced by angiotensin II

Pathological cardiac hypertrophy is a major risk factor for cardiovascular morbidity and mortality. Histone demethylases (KDMs) are emerging regulators of transcriptional reprograming in cancer, however, their potential role in abnormal heart growth and fibrosis remains largely unknown. The aim of this current study was to examine the role of JMJD1C, an H3K9me2 specific demethylase, in angiotensin II (Ang II) induced cardiac hypertrophy and fibrosis. In this study, we observed that Ang II could increase the expression of JMJD1C detected by Western blot and RT-qPCR in vitro and in vivo. Immunofluorescence staining showed that the treatment of Ang II could increase cardiomyocyte size. RT-qPCR results have shown that Ang II could increase the expression of cell hypertrophic and fibrotic markers in H9c2 cells. Whereas, inhibition of JMJD1C by shRNA and JIB-04, a small molecule histone demethylase inhibitor, significantly reduced Ang II-induced cell hypertrophy, and hypertrophic and fibrotic marker overexpression. Furthermore, cardiomyocyte JMJD1C knockdown decreased Tissue Inhibitor of Metalloproteinases 1 (TIMP1) transcription with pro-fibrotic activity. In conclusion, JMJD1C plays an important role in Ang II-induced cardiac hypertrophy and fibrosis by activating TIMP1 transcription, targeting of JMJD1C may be an effective strategy for the treatment of Ang II-associated cardiac diseases.

Loop diuretic use is associated with skeletal muscle wasting in patients with heart failure

BACKGROUND

Loop diuretics are widely used for the management of fluid retention in patients with heart failure (HF). Sarcopenia, defined as decreased skeletal muscle mass, is frequently present in patients with HF and is associated with poor prognosis. The effects of loop diuretics on skeletal muscle in HF patients have not been fully elucidated. Here, we investigated the impact of loop diuretics on the skeletal muscle mass in patients with HF.

METHODS

We conducted a subanalysis of a cross-sectional study from 10 hospitals evaluating 155 patients with HF (age 67 ± 13 yrs, 69% men).

RESULTS

We compared the HF patients who were treated with loop diuretics (n = 120) with the patients who were not (n = 35). The thigh and arm circumferences were significantly small in the group treated with loop diuretics compared to those not so treated (39.9 ± 4.8 vs. 43.5 ± 6.9 cm, p < 0.001 and 26.7 ± 3.5 vs. 28.9 ± 6.2 cm, p < 0.001, respectively). In a univariate analysis, higher age, lower body mass index, lower hemoglobin, and loop diuretic use were significantly associated with smaller thigh circumference. In a multivariable analysis, the use of loop diuretics was independently associated with smaller thigh circumference (β = -0.51, 95% confidence interval -0.98 to -0.046, p = 0.032).

CONCLUSION

Loop diuretics are associated with decreased thigh and arm circumferences in patients with HF, independent of the severity of HF. Our findings revealed for the first time the adverse effects of loop diuretics on skeletal muscle wasting. These findings will have a significant impact in clinical practice regarding the frequent use of loop diuretics in HF patients.

Towards extracellular matrix normalization for improved treatment of solid tumors

It is currently challenging to eradicate cancer. In the case of solid tumors, the dense and aberrant extracellular matrix (ECM) is a major contributor to the heterogeneous distribution of small molecule drugs and nano-formulations, which makes certain areas of the tumor difficult to treat. As such, much research is devoted to characterizing this matrix and devising strategies to modify its properties as a means to facilitate the improved penetration of drugs and their nano-formulations. This contribution presents the current state of knowledge on the composition of normal ECM and changes to ECM that occur during the pathological progression of cancer. It also includes discussion of strategies designed to modify the composition/properties of the ECM as a means to enhance the penetration and transport of drugs and nano-formulations within solid tumors. Moreover, a discussion of approaches to image the ECM, as well as ways to monitor changes in the ECM as a function of time are presented, as these are important for the implementation of ECM-modifying strategies within therapeutic interventions. Overall, considering the complexity of the ECM, its variability within different tissues, and the multiple pathways by which homeostasis is maintained (both in normal and malignant tissues), the available literature - while promising - suggests that improved monitoring of ECM remodeling in vivo is needed to harness the described strategies to their full potential, and match them with an appropriate chemotherapy regimen.

Circulating Biomarkers Predicting Longitudinal Changes in Left Ventricular Structure and Function in a General Population

Background Serial imaging studies in the general population remain important to evaluate the usefulness of pathophysiologically relevant biomarkers in predicting progression of left ventricular (LV) remodeling and dysfunction. Here, we assessed in a general population whether these circulating biomarkers at baseline predict longitudinal changes in LV structure and function. Methods and Results In 592 participants (mean age, 50.8 years; 51.4% women; 40.5% hypertensive), we derived echocardiographic indexes reflecting LV structure and function at baseline and after 4.7 years. At baseline, we measured alkaline phosphatase, markers of collagen turnover (procollagen type I, C-terminal telopeptide, matrix metalloproteinase-1) and high-sensitivity cardiac troponin T. We regressed longitudinal changes in LV indexes on baseline biomarker levels and reported standardized effect sizes as a fraction of the standard deviation of LV change. After full adjustment, a decline in LV longitudinal strain (-14.2%) and increase in E/e' ratio over time (+18.9%; P≤0.019) was associated with higher alkaline phosphatase activity at baseline. Furthermore, longitudinal strain decreased with higher levels of collagen I production and degradation at baseline (procollagen type I, -14.2%; C-terminal telopeptide, -16.4%; P≤0.029). An increase in E/e' ratio over time was borderline associated with lower matrix metalloproteinase-1 (+9.8%) and lower matrix metalloproteinase-1/tissue inhibitor of metalloproteinase-1 ratio (+11.9%; P≤0.041). Higher high-sensitivity cardiac troponin T levels at baseline correlated significantly with an increase in relative wall thickness (+23.1%) and LV mass index (+18.3%) during follow-up ( P≤0.035). Conclusions We identified a set of biomarkers predicting adverse changes in LV structure and function over time. Circulating biomarkers reflecting LV stiffness, injury, and collagen composition might improve the identification of subjects at risk for subclinical cardiac maladaptation.

Collagen Biomarkers and Incidence of New Onset of Atrial Fibrillation in Subjects With No Overt Cardiovascular Disease at Baseline: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Atrial fibrosis is a hallmark of structural remodeling in atrial fibrillation (AF). Plasma procollagen type III N-terminal propeptide (PIIINP) reflects collagen synthesis and degradation while collagen type I carboxy-terminal telopeptide (ICTP) reflects collagen degradation. We aimed to study baseline plasma PIIINP and ICTP and their associations with incident AF in participants initially free of overt cardiovascular disease.

METHODS

In a stratified sample of the Multi-Ethnic Study of Atherosclerosis, initially aged 45-84 years, 3071 participants had both PIIINP and ICTP measured at baseline. Incident AF in 10-year follow-up was based on a hospital International Classification of Diseases code for AF or atrial flutter, in- or outpatient Medicare claims through 2011 (primarily in those aged 65-84 years), or ECG 10 years after baseline (n=357). The associations of PIIINP and ICTP with incident AF were estimated using Poisson regression with follow-up time offset.

RESULTS

Baseline PIIINP (5.50±1.55 µg/L) and ICTP (mean±SD, 3.41±1.37 µg/L) were positively related (both P<0.0001) to incident AF in a model adjusting for age, race/ethnicity, and sex, with an apparent threshold (relative incidence density 2.81 [1.94-4.08] for PIIINP ≥8.5 µg/L [3.5% of the sample] and 3.46 [2.36-5.07] for ICTP ≥7 µg/L [1.7% of the sample]). Findings were attenuated but remained statistically significant after further adjustment for systolic blood pressure, height, body mass index, smoking, and renal function. Additional adjustment for other risk factors and biomarkers of inflammation did not alter conclusions.

CONCLUSIONS

Plasma collagen biomarkers, particularly at elevated levels, were associated with excess risk for AF.

Collagen biomarkers predict new onset of hypertension in normotensive participants: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

Vascular remodeling associated with increased extracellular matrix (ECM) may precede hypertension. Procollagen type III N-terminal propeptide (PIIINP) and collagen type I carboxy-terminal telopeptide (ICTP) reflect collagen turnover and are important in ECM remodeling. PIIINP and ICTP are increased in cardiovascular diseases (CVD). We hypothesized that PIIINP and ICTP among normotensives predict incident hypertension.

METHODS

We included 1252 Multi-Ethnic Study of Atherosclerosis participants with mean age 58.1 ± 12.4 years, 48% men, free of overt CVD, having SBP and DBP less than 130/85 mmHg and not using any antihypertensive medication, and having plasma PIIINP and ICTP measurements, all assessed at baseline. We studied the association of baseline PIIINP and ICTP with the relative incidence density (RID) of incident hypertension, defined as SBP/DBP at least 140/90 mmHg, or antihypertensive therapy use during follow-up (four examinations over median 9.4 years).

RESULTS

Baseline mean SBP/DBP was 110.9 ± 14.0/67.9 ± 10.4 mmHg. Mean concentration of PIIINP was 5.39 ± 1.95 μg/l and ICTP was 3.18 ± 1.39 μg/l. During follow-up visits, 35.9% of the participants developed hypertension. After adjustment for age, race, and sex there was a significant RID for new onset of hypertension of 1.16 (1.06, 1.28), P = 0.0017 for PIIINP and 1.20 (1.08,1.33) for ICTP, P = 0.0008. After additional adjustment for renal function, CVD risk factors and inflammatory variables, RID for new onset hypertension was 1.28 (1.15,1.42), P < 0.001 for PIIINP and 1.29 (1.15,1.44) for ICTP, P < 0.0001.

CONCLUSION

Biomarkers of ECM remodeling predicted the development of hypertension in normotensive participants free of overt CVD.

Procollagen type I carboxy-terminal propeptide (PICP) and MMP-2 are potential biomarkers of myocardial fibrosis in patients with hypertrophic cardiomyopathy

BACKGROUND

Whether current proposed biomarkers of myocardial fibrosis (BMFs) actually reflect the changes in fibrous characteristics of myocardial tissue remains unclear. The relation between peripheral BMFs and histological myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM) has been unknown.

METHODS AND RESULTS

We studied 52 HCM patients who underwent a transaortic extended septal myectomy. Complete medical history was collected, and related examinations were performed. Echocardiography and cardiovascular magnetic resonance were employed to characterize cardiac morphology and function. Procollagen type I carboxy-terminal propeptide (PICP), C-terminal telopeptide of type I collagen (CITP), matrix metalloproteinases (total MMP-2 and total MMP-9), and tissue inhibitor of metalloproteinase 1 (TIMP-1) levels in both plasma and myocardial tissues were determined and compared. Myocardial fibrosis was detected with Masson's trichrome staining, and collagen volume fraction (CVF) was calculated. There was a significant correlation between plasma PICP levels and myocardial PICP contents (r=0.382, P=.007). Besides, plasma PICP (r=0.332, P=.020) levels correlated positively with CVF. In addition, plasma TIMP-1 levels were significantly correlated with myocardial TIMP-1 contents (r=0.282, P=.043). Plasma MMP-2 levels correlated positively with CVF (r=0.379, P=.006). Patients who took calcium channel blockers (CCBs; diltiazem or verapamil) had significantly lower plasma PICP levels, myocardial PICP content, and CVF in comparison with those who did not take CCBs.

CONCLUSIONS

In patients with HCM, plasma PICP and MMP-2 levels quantitatively reflect myocardial fibrosis, suggesting that PICP and MMP-2 may be used as reliable BMFs. CCBs may attenuate cardiac fibrosis in patients with HCM.

Effect of Peritoneal Dialysis on Serum Fibrosis Biomarkers in Patients with Refractory Congestive Heart Failure

Background: Cardiac collagen remodeling is important in the progression of heart failure. Estimation of cardiac collagen turnover by serum levels of serological markers is used for monitoring cardiac tissue repair and fibrosis. Peritoneal dialysis (PD) is used for the long-term management of refractory congestive heart failure (CHF). In this study, we investigated the effect of PD treatment on circulating fibrosis markers levels in patients with refractory CHF and fluid overload. Methods: Twenty-five patients with refractory CHF treated with PD were prospectively enrolled in the study. Circulating fibrosis markers procollagen type III C-peptide (PIIINP), matrix metalloproteinase 2 (MMP-2), and tissue inhibitor of metalloproteinases I (TIMP-1) levels were checked at baseline and after three and six months of treatment. Results: The clinical benefit of PD manifested by improved NYHA functional class and reduced hospitalization rate. Serum brain natriuretic peptide (BNP) levels decreased significantly during the treatment. Serum MMP-2 and TIMP-1 decreased significantly on PD. Circulating PIIINP showed two patterns of change, either decreased or increased following PD treatment. Patients in whom circulating PIIINP decreased had significantly lower baseline serum albumin, lower baseline mean arterial blood pressure, higher serum CRP, and a less significant improvement in hospitalization rate compared to the patients in whom circulating PIIINP increased. Patients in whom all three markers decreased demonstrated a trend to longer survival compared to patients whose markers increased or did not change. Conclusion: In refractory CHF patients PD treatment was associated with a reduction in circulating fibrosis markers.

Early detection of organ involvement in Fabry disease by biomarker assessment in conjunction with LGE cardiac MRI: results from the SOPHIA study

BACKGROUND

Initiation of enzyme replacement therapy (ERT) early in the Fabry disease course may facilitate better outcomes than in patients with advanced disease. Early diagnosis is often hindered by the heterogeneous nature of signs and symptoms, and by the presentation of atypical phenotypes.

METHODS

The Sophisticated Assessment of Disease Burden in Patients with Fabry Disease study (SOPHIA; ClinicalTrials.gov, NCT01210196) evaluated clinical and diagnostic assessments for early detection of Fabry-related organ pathology in ERT-naïve patients with mild FD symptoms. Assessments included cardiac magnetic resonance imaging with late gadolinium enhancement (LGE-CMR), echocardiography, 24-h Holter electrocardiography, and biomarkers of FD and fibrosis.

RESULTS

35 patients with mean (SD) baseline age of 45.0 (10.2) years were included and assessed at baseline, 12 months, and (optionally) at 24 months. At baseline, LGE-CMR and elevated procollagen III N-terminal propeptide, sphingosine-1-phosphate, and globotriaosylsphingosine were the most prevalent indicators of early Fabry-related pathology. LGE was already present in 58.8% of patients with normal left ventricular mass index. 15.2% of patients showed grade 1 diastolic dysfunction. QRS duration increased from baseline to last observation, particularly in patients with severe baseline fibrosis. Fibrosis progressed from baseline to last observation, especially in patients with baseline LGE ≥ 2.50 mL (3.65 [1.14] mL vs 6.74 [1.10] mL). Statistically significant correlations were found between LGE volume and high-sensitivity troponin T, and between LGE volume and fragments of urinary collagen alpha-1 (I), (III), and (VII), and collagen alpha-3 (V).

CONCLUSIONS

Fibrosis may become apparent before left ventricular hypertrophy occurs. LGE-CMR imaging is superior to conventional echocardiography for detecting early cardiomyopathy in FD and, in conjunction with biomarker tests, may help detect early organ involvement in mild FD.

Histone lysine dimethyl-demethylase KDM3A controls pathological cardiac hypertrophy and fibrosis

Left ventricular hypertrophy (LVH) is a major risk factor for cardiovascular morbidity and mortality. Pathological LVH engages transcriptional programs including reactivation of canonical fetal genes and those inducing fibrosis. Histone lysine demethylases (KDMs) are emerging regulators of transcriptional reprogramming in cancer, though their potential role in abnormal heart growth and fibrosis remains little understood. Here, we investigate gain and loss of function of an H3K9me2 specific demethylase, Kdm3a, and show it promotes LVH and fibrosis in response to pressure-overload. Cardiomyocyte KDM3A activates Timp1 transcription with pro-fibrotic activity. By contrast, a pan-KDM inhibitor, JIB-04, suppresses pressure overload-induced LVH and fibrosis. JIB-04 inhibits KDM3A and suppresses the transcription of fibrotic genes that overlap with genes downregulated in Kdm3a-KO mice versus WT controls. Our study provides genetic and biochemical evidence for a pro-hypertrophic function of KDM3A and proof-of principle for pharmacological targeting of KDMs as an effective strategy to counter LVH and pathological fibrosis.

Circulating markers of collagen types I, III, and IV in patients with dilated cardiomyopathy: relationships with myocardial collagen expression

Aims

Collagen‐derived peptides such as collagen I C‐terminal telopeptide (CITP) and procollagen III N‐terminal propeptide (PIIINP) have been conventionally used as markers of cardiac fibrosis. Collagen IV 7S domain (P4NP 7S) has been recently reported to be correlated with haemodynamics in patients with acute heart failure. We investigated whether these markers reflect cardiac remodelling and myocardial collagen expression.

Methods and results

In 80 patients with dilated cardiomyopathy, relationships of CITP, PIIINP, and P4NP 7S to clinical and echocardiographic variables were analysed. CITP and PIIINP were inversely correlated with estimated glomerular filtration rate (r = −0.41, P < 0.001 and r = −0.32, P = 0.004, respectively); P4NP 7S was positively correlated with B‐type natriuretic peptide (r = 0.32, P = 0.003) and γ‐glutamyltransferase (r = 0.38, P < 0.001). These correlations were significant even after adjustment by potential confounders, whereas all three collagen markers were not independently correlated with ejection fraction nor with left ventricular (LV) diastolic diameter. In 33 patients undergoing endomyocardial biopsy, myocardial collagen I and III mRNA expressions were correlated with LV end‐diastolic volume index (r = 0.42, P = 0.02 and r = 0.54, P = 0.002, respectively), whereas myocardial collagen IV mRNA expression was not correlated with LV end‐diastolic volume index nor with ejection fraction. Each collagen‐derived peptide was not significantly correlated with the myocardial expression of their corresponding collagen mRNA.

Conclusions

Our study shows that CITP, PIIINP, and P4NP 7S do not reflect myocardial collagen mRNA expression but presumably reflect extra‐cardiac organ injury in heart failure.

Cardiac fibrosis: Cell biological mechanisms, molecular pathways and therapeutic opportunities

Cardiac fibrosis is a common pathophysiologic companion of most myocardial diseases, and is associated with systolic and diastolic dysfunction, arrhythmogenesis, and adverse outcome. Because the adult mammalian heart has negligible regenerative capacity, death of a large number of cardiomyocytes results in reparative fibrosis, a process that is critical for preservation of the structural integrity of the infarcted ventricle. On the other hand, pathophysiologic stimuli, such as pressure overload, volume overload, metabolic dysfunction, and aging may cause interstitial and perivascular fibrosis in the absence of infarction. Activated myofibroblasts are the main effector cells in cardiac fibrosis; their expansion following myocardial injury is primarily driven through activation of resident interstitial cell populations. Several other cell types, including cardiomyocytes, endothelial cells, pericytes, macrophages, lymphocytes and mast cells may contribute to the fibrotic process, by producing proteases that participate in matrix metabolism, by secreting fibrogenic mediators and matricellular proteins, or by exerting contact-dependent actions on fibroblast phenotype. The mechanisms of induction of fibrogenic signals are dependent on the type of primary myocardial injury. Activation of neurohumoral pathways stimulates fibroblasts both directly, and through effects on immune cell populations. Cytokines and growth factors, such as Tumor Necrosis Factor-α, Interleukin (IL)-1, IL-10, chemokines, members of the Transforming Growth Factor-β family, IL-11, and Platelet-Derived Growth Factors are secreted in the cardiac interstitium and play distinct roles in activating specific aspects of the fibrotic response. Secreted fibrogenic mediators and matricellular proteins bind to cell surface receptors in fibroblasts, such as cytokine receptors, integrins, syndecans and CD44, and transduce intracellular signaling cascades that regulate genes involved in synthesis, processing and metabolism of the extracellular matrix. Endogenous pathways involved in negative regulation of fibrosis are critical for cardiac repair and may protect the myocardium from excessive fibrogenic responses. Due to the reparative nature of many forms of cardiac fibrosis, targeting fibrotic remodeling following myocardial injury poses major challenges. Development of effective therapies will require careful dissection of the cell biological mechanisms, study of the functional consequences of fibrotic changes on the myocardium, and identification of heart failure patient subsets with overactive fibrotic responses.

Pathophysiology of acute heart failure syndrome: a knowledge gap

Although much remains unknown regarding the pathophysiology of acute heart failure (AHF), precipitating events are thought to involve a complex set of interactions between the heart, kidneys, and peripheral vasculature. In addition to these interactions, which are considered the primary abnormalities in patients with AHF, several other organ systems may also be affected and contribute to disease progression. Currently available scientific literature suggests that the natural history and pathophysiology of AHF consists of two phases: (1) an "initiation phase" involving a series of triggering events, and (2) an "amplification phase," in which multiple mechanisms contribute to worsening HF and exacerbate end-organ damage. Biomarkers of cardiac, renal, pulmonary, and other organ function have been identified during episodes of AHF, including brain natriuretic peptide, troponin I, and troponin T; biomarkers associated with AHF have proven to be useful tools for studying the pathophysiology of the syndrome, predicting clinical outcomes, and identifying patient management strategies. Despite considerable advances in recent years, AHF continues to be a leading cause of hospitalization and death in patients with chronic HF. Moreover, AHF remains a major healthcare issue exacting a considerable cost burden. Addressing this ongoing unmet need requires prioritizing efforts to better understand the natural history and pathophysiology of AHF; only then can targeted therapies be developed to prevent rehospitalization in patients with AHF, or at least alter the trajectory of disease progression toward improved clinical outcomes.