Galectin-3 as an independent prognostic factor after heart transplantation

BACKGROUND

Galectin-3 (GAL3) is linked to the prognosis of patients with heart failure and after heart transplantation (HTx). We assessed the prognostic role of GAL3 in a long-term follow-up after HTx.

METHODS

HTx patients (N = 121) were evaluated in a single-center, noninterventional, prospective, observational study. The median follow-up was 96 months (2,942 days, interquartile range (IQR) 2,408-3,264 days), and 40 patients died. GAL3 was measured before HTx, +10 days after HTx, and during the first posttransplant year. Survival analysis (all-cause mortality) was performed with adjustments for clinical and laboratory variables.

RESULTS

The median pretransplant GAL3 level was 18.0 μg/L (IQR 14.0-25.9), and higher values were associated with older age, worse kidney function, left ventricular assist device use before HTx, a higher IMPACT score and mortality. Increased pretransplant GAL3 predicted shorter survival time (HR 2.05, 95% CI 1.09-3.85, p<0.05). Similar prognostic power had GAL3 on the 10th posttransplant day (HR 2.03, 95% CI 1.08-3.82, p<0.05). GAL3 was an independent predictor of death after adjustment for clinical variables (age, infection, diabetes, smoking, IMPACT score, troponin).

CONCLUSIONS

GAL3 was significantly associated with all-cause mortality after adjusting for clinical and laboratory variables and may serve as an additional prognostic biomarker. This article is protected by copyright. All rights reserved.

Galectin-3: A Potential Prognostic and Diagnostic Marker for Heart Disease and Detection of Early Stage Pathology

The use of molecular biomarkers for the early detection of heart disease, before their onset of symptoms, is an attractive novel approach. Ideal molecular biomarkers, those that are both sensitive and specific to heart disease, are likely to provide a much earlier diagnosis, thereby providing better treatment outcomes. Galectin-3 is expressed by various immune cells, including mast cells, histiocytes and macrophages, and plays an important role in diverse physiological functions. Since galectin-3 is readily expressed on the cell surface, and is readily secreted by injured and inflammatory cells, it has been suggested that cardiac galectin-3 could be a marker for cardiac disorders such as cardiac inflammation and fibrosis, depending on the specific pathogenesis. Thus, galectin-3 may be a novel candidate biomarker for the diagnosis, analysis and prognosis of various cardiac diseases, including heart failure. The goals of heart disease treatment are to prevent acute onset and to predict their occurrence by using the ideal molecular biomarkers. In this review, we discuss and summarize recent developments of galectin-3 as a next-generation molecular biomarker of heart disease. Furthermore, we describe how galectin-3 may be useful as a diagnostic marker for detecting the early stages of various heart diseases, which may contribute to improved early therapeutic interventions.

Galectin-3 as a Next-Generation Biomarker for Detecting Early Stage of Various Diseases

Galectin-3 is a β-galactoside-binding lectin which is important in numerous biological activities in various organs, including cell proliferation, apoptotic regulation, inflammation, fibrosis, and host defense. Galectin-3 is predominantly located in the cytoplasm and expressed on the cell surface, and then often secreted into biological fluids, like serum and urine. It is also released from injured cells and inflammatory cells under various pathological conditions. Many studies have revealed that galectin-3 plays an important role as a diagnostic or prognostic biomarker for certain types of heart disease, kidney disease, viral infection, autoimmune disease, neurodegenerative disorders, and tumor formation. In particular, it has been recognized that galectin-3 is extremely useful for detecting many of these diseases in their early stages. The purpose of this article is to review and summarize the recent literature focusing on the biomarker characteristics and long-term outcome predictions of galectin-3, in not only patients with various types of diseases, but associated animal models.

Plasma and Cardiac Galectin-3 in Patients With Heart Failure Reflects Both Inflammation and Fibrosis

Background—

Galectin (Gal)-3 is a β-galactoside-binding lectin and currently intensely studied as a biomarker in heart failure. Gal-3 also exerts proinflammatory effects, at least in extracardiac tissues. Objective of this study was to characterize the relationship of plasma and myocardial Gal-3 levels with cardiac fibrosis and inflammation in patients with nonischemic dilated cardiomyopathy and inflammatory cardiomyopathy (iCMP).

Methods and Results—

Endomyocardial biopsies and blood samples were obtained from patients with newly diagnosed cardiomyopathy and clinical suspicion of myocarditis. According to histopathologic findings, patients were classified as having dilated cardiomyopathy (n=40) or iCMP (n=75). Cardiac fibrosis was assessed histologically on endomyocardial biopsy sections. In patients with iCMP, myocardial Gal-3 expression significantly correlated with inflammatory cell count on endomyocardial biopsy ( r =0.56; P <0.05). In contrast, an inverse association was observed between myocardial Gal-3 expression and cardiac fibrosis in patients with iCMP ( r =−0.59; P <0.05). In patients with dilated cardiomyopathy, myocardial Gal-3 expression correlated with cardiac fibrosis on left ventricular biopsy ( P =0.63; P <0.01). Of note, in both groups, plasma Gal-3 levels did not correlate with myocardial Gal-3 levels or left ventricular fibrosis, whereas a positive correlation between plasma Gal-3 levels and inflammatory cell count on endomyocardial biopsy was observed in patients with iCMP.

Conclusions—

The present study suggests that myocardial Gal-3 can be considered as a possible marker for both cardiac inflammation and fibrosis, depending on the pathogenesis of heart failure. However, circulating concentrations of Gal-3 do not seem to reflect endomyocardial Gal-3 levels or cardiac fibrosis.

Circulating Galectin-3 Levels Are Persistently Elevated After Heart Transplantation and Are Associated With Renal Dysfunction

OBJECTIVES

This study evaluated changes in serum levels of galectin (Gal)-3 before and after heart transplantation (HTx) and assessed the role of pre-HTx Gal-3 as a biomarker for post-HTx outcomes.

BACKGROUND

Gal-3 is a novel biomarker that reflects cardiac remodeling and fibrosis. Elevated serum Gal-3 levels are associated with poor prognosis in heart failure patients. Whether Gal-3 levels change following HTx and the significance of post-HTx outcomes are unknown.

METHODS

Serum Gal-3 levels were measured in 62 patients at 118 days (Interquartile Range [IQR]: 23 to 798 days) before and 365 days (IQR: 54 to 767 days) post HTx. Cardiac tissue taken during routine post-HTx endomyocardial biopsy was evaluated to assess the correlation between tissue Gal-3 staining and serum Gal-3 levels and with the presence of myocardial hypertrophy and fibrosis.

RESULTS

Serum Gal-3 levels remained significantly elevated (>17.8 ng/ml) in 35 patients (56%) post HTx. There was a significant inverse correlation between Gal-3 levels and glomerular filtration rate measured before and after HTx (p > 0.005). There was no association between Gal-3 serum level and Gal-3 staining of myocardial tissue or with the presence of myocyte hypertrophy and interstitial fibrosis post HTx. Elevated pre-HTx Gal-3 levels were associated with reduced post-HTx exercise capacity, but this association was not significant after adjustment for age, body mass index, and glomerular filtration rate.

CONCLUSIONS

This is the first study to demonstrate the fact that Gal-3 levels remain elevated in the majority of patients despite HTx and is associated with renal dysfunction. Our findings suggest Gal-3 is a systemic rather than cardiac-specific biomarker.

The role of cardiac biochemical markers in aortic stenosis

Calcified aortic stenosis is one of the most common causes of heart failure in the elderly. Current guidelines recommend aortic valve replacement in patients with severe disease and evidence of decompensation based on either symptoms or impaired systolic ejection fraction. However, symptoms are often subjective whilst impaired ejection fraction is not a sensitive marker of ventricular decompensation. Interest has surrounded the use of cardiac biochemical markers as objective measures of left ventricular decompensation in aortic stenosis. We will first examine mechanisms of release of biochemical markers associated with myocardial wall stress (BNP/NT-proBNP), myocardial fibrosis (markers of collagen metabolism, galectin-3, soluble ST2) and myocyte death/myocardial ischemia (high-sensitivity cardiac troponins, heart-type fatty acid binding protein, myosin-binding protein C); and discuss future directions of these markers.

Absence of cystatin C involvement in ventricular remodelling and heart failure

Cystatin C (CysC) is a protease encoded by housekeeping genes. Although its prognostic value in heart failure (HF) is well known, it is debatable whether this value is due to the greater accuracy of CysC in calculating the glomerular filtration rate or to its involvement in pathological ventricular remodelling. The aim of this study was to determine whether CysC expression changes in the myocardium of foetuses of different ages and in the myocardium of adults with various cardiovascular diseases, as well as to analyse the correlation between its serum concentrations and cardiac structure and morphology in a patient group with HF.

PATIENTS AND METHODS

We analysed the correlations (Pearson's r and Spearman's test) between the serum CysC levels and echocardiographic parameters of 351 patients with HF. We also performed immunohistochemical staining for CysC, metalloproteinase-9 (MMP-9) and desmin in 9 cardiac tissue samples from autopsies of 4 foetuses of different gestational ages and 5 healthy adults or adults with cardiovascular disease.

RESULTS

For the patients with HF, there was no correlation between the CysC concentrations and the cardiac parameters measured by 2D echocardiography. The immunohistochemistry showed a weak background staining for CysC in all samples, regardless of age and the presence or absence of cardiovascular diseases.

CONCLUSIONS

Our results suggest that CysC does not have a significant role in the pathological remodelling of the left ventricle in HF.

Galectin-3 level and the severity of cardiac diastolic dysfunction using cellular and animal models and clinical indices

Heart failure with preserved ejection fraction (HFPEF) is characterized by myocardial interstitial fibrosis. A total of 146 patients with HFPEF, were recruited. HFPEF severity was determined using Doppler imaging (E/Em) and also cardiac magnetic resonance imaging (CMRI). Canine modeling of HFPEF was induced by aortic banding. Hemodynamic and echocardiographic data were obtained before and after pressure loading and myocardial Galectin-3 was determined. Mechanical stretch of cultured cardiomyocytes served as the cellular model of HFPEF. Patients with severe HFPEF had significantly higher plasma Galectin-3 levels. Significant correlation between plasma Galectin-3 and E/Em in advanced HFPEF patients was noted. After 2 weeks of pressure overload in canine models, the protein expression of Galectin-3 from LV myocardial tissue was significantly increased (p < 0.01) compared with controls. Galectin-3 expression paralleled the severity of LV diastolic dysfunction by evaluation of CMRI (r = -0.58, p = 0.003) and tissue fibrosis (r = 0.59, p = 0.002). After adjusting for confounders for diastolic dysfunction, Galectin-3 levels were still associated with diastolic parameters both in humans (p < 0.001) and canine model (p = 0.041). Mechanical stretch increased Galectin-3 secretion in cultured cardiomyocytes. Both plasma and myocardial Galectin-3 levels correlated with severity of cardiac diastolic dysfunction.

Galectin-3 Participates in Cardiovascular Remodeling Associated With Obesity

Remodeling, diastolic dysfunction, and arterial stiffness are some of the alterations through which obesity affects the cardiovascular system. Fibrosis and inflammation are important mechanisms underlying cardiovascular remodeling, although the precise promoters involved in these processes are still unclear. Galectin-3 (Gal-3) induces inflammation and fibrosis in the cardiovascular system. We have investigated the potential role of Gal-3 in cardiac damage in morbidly obese patients, and we have evaluated the protective effect of the Gal-3 inhibition in the occurrence of cardiovascular fibrosis and inflammation in an experimental model of obesity. Morbid obesity is associated with alterations in cardiac remodeling, mainly left ventricular hypertrophy and diastolic dysfunction. Obesity and hypertension are the main determinants of left ventricular hypertrophy. Insulin resistance, left ventricular hypertrophy, and circulating levels of C-reactive protein and Gal-3 are associated with a worsening of diastolic function in morbidly obese patients. Obesity upregulates Gal-3 production in the cardiovascular system in a normotensive animal model of diet-induced obesity by feeding for 6 weeks a high-fat diet (33.5% fat). Gal-3 inhibition with modified citrus pectin (100 mg/kg per day) reduced cardiovascular levels of Gal-3, total collagen, collagen I, transforming and connective growth factors, osteopontin, and monocyte chemoattractant protein-1 in the heart and aorta of obese animals without changes in body weight or blood pressure. In morbidly obese patients, Gal-3 levels are associated with diastolic dysfunction. In obese animals, Gal-3 blockade decreases cardiovascular fibrosis and inflammation. These data suggest that Gal-3 could be a novel therapeutic target in cardiac fibrosis and inflammation associated with obesity.

Emerging risk biomarkers in cardiovascular diseases and disorders

Present review article highlights various cardiovascular risk prediction biomarkers by incorporating both traditional risk factors to be used as diagnostic markers and recent technologically generated diagnostic and therapeutic markers. This paper explains traditional biomarkers such as lipid profile, glucose, and hormone level and physiological biomarkers based on measurement of levels of important biomolecules such as serum ferritin, triglyceride to HDLp (high density lipoproteins) ratio, lipophorin-cholesterol ratio, lipid-lipophorin ratio, LDL cholesterol level, HDLp and apolipoprotein levels, lipophorins and LTPs ratio, sphingolipids, Omega-3 Index, and ST2 level. In addition, immunohistochemical, oxidative stress, inflammatory, anatomical, imaging, genetic, and therapeutic biomarkers have been explained in detail with their investigational specifications. Many of these biomarkers, alone or in combination, can play important role in prediction of risks, its types, and status of morbidity. As emerging risks are found to be affiliated with minor and microlevel factors and its diagnosis at an earlier stage could find CVD, hence, there is an urgent need of new more authentic, appropriate, and reliable diagnostic and therapeutic markers to confirm disease well in time to start the clinical aid to the patients. Present review aims to discuss new emerging biomarkers that could facilitate more authentic and fast diagnosis of CVDs, HF (heart failures), and various lipid abnormalities and disorders in the future.

Galectin-3 in heart failure with preserved ejection fraction. A RELAX trial substudy (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Diastolic Heart Failure)

OBJECTIVES

This study hypothesized that elevated galectin-3 (Gal-3) levels would identify patients with more advanced heart failure (HF) with preserved ejection fraction (HFpEF) as assessed by key pathophysiological domains.

BACKGROUND

Gal-3 is implicated in the pathogenesis of cardiac fibrosis but is also increased with normal aging and renal dysfunction. Cardiac fibrosis may contribute to cardiac dysfunction, exercise intolerance, and congestion in HFpEF.

METHODS

Two hundred eight patients from the RELAX (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Diastolic Heart Failure) trial of sildenafil in HFpEF had Gal-3 measured at enrollment. Pathophysiological domains assessed included biomarkers of neurohumoral activation, fibrosis, inflammation and myocardial necrosis, congestion severity and quality of life, cardiac structure and function, and exercise performance. Analysis adjusted for age, sex, and/or cystatin-C levels. Potential interaction between baseline Gal-3 and treatment (sildenafil) effect on the RELAX study primary endpoint (change in peak oxygen consumption) was tested.

RESULTS

Gal-3 levels were associated with age and severity of renal dysfunction. Adjusting for age, sex, and/or cystatin-C, Gal-3 was not associated with biomarkers of neurohumoral activation, fibrosis, inflammation or myocardial necrosis, congestion or quality-of-life impairment, cardiac remodeling or dysfunction, or exercise intolerance. Gal-3 did not identify patients who responded to phosphodiesterase type 5 (PDE-5) inhibitors (interaction p = 0.53).

CONCLUSIONS

In overt HFpEF, Gal-3 was related to severity of renal dysfunction and accounting for this, was not independently associated with severity of pathophysiological derangements or response PDE-5 inhibition. These findings underscore the need to adjust for renal function when interpreting Gal-3 levels, and call into question the value of Gal-3 to quantify disease severity in overt HFpEF.

Renal function largely influences Galectin-3 prognostic value in heart failure

BACKGROUND

Galectin-3 (Gal-3) has been associated with cardiac remodeling and heart failure (HF) prognosis. Renal function is also a well known HF prognostic indicator. The link between renal insufficiency, HF, and Gal-3 is not completely elucidated.

METHODS AND RESULTS

We explored the association between Gal-3 and renal function in a cohort of 876 consecutive ambulatory patients with HF (mean age: 68 years; mean left ventricular ejection fraction [LVEF]: 36%), 52.2% had HF etiology of ischemic heart disease. Circulating Gal-3 was highly correlated with estimated glomerular filtration rate (eGFR), calculated with either the chronic kidney disease-epidemiology (CKD-EPI) equation (r = -0.64) or the CKD-EPI-cystatin-C equation (r = -0.59) and with Cystatin-C levels (r = 0.70), after adjusting for age, sex, New York Heart Association (NYHA) functional class, LVEF, and HF etiology (all p<0.001). Patients were stratified by CKD-EPI-eGFR (ml/min/1.73 m(2)), as follows: ≥ 60 (n = 218), 30 to 59 (n = 434), and <30 (n = 224). In these strata, Gal-3 significantly increased (median [IQR]: 12.3 [10.4-15.6]; 16.1 [13-19.8]; and 24.5 [20-33.8] ng/ml, respectively; trend p < 0.001). This was independent of NYHA functional class (I-II and III-IV) and LVEF (<45% and ≥ 45%). Gal-3 was associated with mortality in univariate analyses, but after adjusting for CKD-EPI-eGFR, the hazard ratios were 1.10 (95% CI: 0.89-1.34, p = 0.39) for all cause death, and 0.90 (95% CI: 0.68-1.21, p = 0.50) for cardiovascular death. Similar results were obtained with eGFRs calculated with the CKD-EPI-cystatin-C equation.

CONCLUSION

Circulating Gal-3 was highly associated with renal function in outpatients with HF. The value of Gal-3 for HF prognosis declined after adjusting for renal function.

Utility of galectin-3 as a prognostic biomarker in heart failure: where do we stand?

BACKGROUND

Heart failure (HF) continues to be an illness of daunting proportions with a four- year mortality touching 50%. Biomarkers for prognosticating patients with heart failure have generated immense interest. Several studies have been conducted on a novel biomarker, galectin-3 to assess its prognostic effect in heart failure populations. However, the studies have generated conflicting results. Hence a systematic review was done to assess the utility of galectin-3 as a prognostic biomarker in HF.

DESIGN

This study was a systematic review.

METHODS

A literature search was done using terms 'galectin-3 and heart' and 'galectin-3 and heart failure' in MEDLINE, Science Direct, Scopus, Springer Link, Cochrane Library and Google Scholar for original articles using a predefined inclusion/exclusion criteria.

RESULTS

Altogether 27 original articles were selected for the systematic review. Multivariate analysis showed galectin-3 to be ineffective in predicting all-cause mortality and cardiovascular mortality especially under the influence of factors such as estimated glomerular filtration rate (eGFR), left ventricular ejection fraction (LVEF) and N-terminal pro-B-type natriuretic peptide (NTproBNP). Galectin-3 was not found to be superior to NTproBNP, sST2, GDF-15 or C-reactive protein (CRP) as a predictor of mortality. However the combination of natriuretic peptides and galectin-3 has been observed to be superior in predicting mortality compared to either of the biomarkers alone. The role of galectin-3 in remodelling has not been conclusively proven as seen in earlier pre-clinical studies.

CONCLUSION

The current weight of evidence does not suggest galectin-3 to be a predictor of mortality. However, assessment of galectin-3 in a multi-biomarker panel may have a distinct advantage in prognosticating patients with heart failure.