Galectin-3 is essential for early wound healing and ventricular remodeling after myocardial infarction in mice

Galectin-3 levels in children with cystic fibrosis

Cystic fibrosis (CF) is a multisystemic disease in which airway obstruction, infection, and inflammation play a critical role in the pathogenesis and progression of CF lung disease. The carbohydrate-binding protein Galectin-3 is increased in several inflammatory and fibrotic diseases and has recently been forwarded as a biomarker in these diseases. We aimed to define the role of serum Galectin-3 in children with CF by comparison with healthy subjects. This is a cross-sectional, case-control study. 143 CF and 30 healthy subjects were enrolled in the study. Peripheral blood and sputum concentrations of Galectins-3, interleukin (IL)-17A, IL-8, and neutrophil elastase (NE) were determined with commercial ELISA kits. There was no significant difference between the groups in age and gender (p = 0.592, p = 0.613, respectively). Serum Galectin-3 and NE concentrations were higher in the patient group than in healthy controls (p = 0.002, p < 0.001, respectively). There were no significant differences between groups according to IL-17A and IL-8 concentrations. Serum Galectin-3 was correlated with age (r = 0.289, p < 0.001) and body mass index (BMI) (r = 0.493, p < 0.001) in children with CF. Sputum Galectin-3 levels are negatively correlated with percent predictive forced expiratory volume in 1 s (FEV1) (r =  - 0.297, p = 0.029), FEV1 z-score, (r =  - 0.316, p = 0.020), percent predictive forced vital capacity (FVC) (r =  - 0.347, p = 0.010), and FVC z-score (r =  - 0.373, p = 0.006).   Conclusion: The study shows that serum Galectin-3 levels increased in clinically stable CF patients, and serum Galectin-3 response may depend on age, gender, and BMI. The sputum Galectin-3 was found to be negatively correlated with patients' lung functions. What is known: • Galectin-3 is a key regulator of chronic inflammation in the lung, liver, kidney, and tumor microenvironment. What is new: • Children with cystic fibrosis (CF) have higher serum Galectin-3 concentrations than healthy children. • Serum Galectin-3 expression influenced by age, BMI, and gender in children with CF.

Unraveling the role of galectin-3 in cardiac pathology and physiology

Galectin-3 (Gal-3) is a carbohydrate-binding protein with multiple functions. Gal-3 regulates cell growth, proliferation, and apoptosis by orchestrating cell-cell and cell-matrix interactions. It is implicated in the development and progression of cardiovascular disease, and its expression is increased in patients with heart failure. In atherosclerosis, Gal-3 promotes monocyte recruitment to the arterial wall boosting inflammation and atheroma. In acute myocardial infarction (AMI), the expression of Gal-3 increases in infarcted and remote zones from the beginning of AMI, and plays a critical role in macrophage infiltration, differentiation to M1 phenotype, inflammation and interstitial fibrosis through collagen synthesis. Genetic deficiency of Gal-3 delays wound healing, impairs cardiac remodeling and function after AMI. On the contrary, Gal-3 deficiency shows opposite results with improved remodeling and function in other cardiomyopathies and in hypertension. Pharmacologic inhibition with non-selective inhibitors is also protective in cardiac disease. Finally, we recently showed that Gal-3 participates in normal aging. However, genetic absence of Gal-3 in aged mice exacerbates pathological hypertrophy and increases fibrosis, as opposed to reduced fibrosis shown in cardiac disease. Despite some gaps in understanding its precise mechanisms of action, Gal-3 represents a potential therapeutic target for the treatment of cardiovascular diseases and the management of cardiac aging. In this review, we summarize the current knowledge regarding the role of Gal-3 in the pathophysiology of heart failure, atherosclerosis, hypertension, myocarditis, and ischemic heart disease. Furthermore, we describe the physiological role of Gal-3 in cardiac aging.

Cardiomyocyte precursors generated by direct reprogramming and molecular beacon selection attenuate ventricular remodeling after experimental myocardial infarction

BACKGROUND

Direct cardiac reprogramming is currently being investigated for the generation of cells with a true cardiomyocyte (CM) phenotype. Based on the original approach of cardiac transcription factor-induced reprogramming of fibroblasts into CM-like cells, various modifications of that strategy have been developed. However, they uniformly suffer from poor reprogramming efficacy and a lack of translational tools for target cell expansion and purification. Therefore, our group has developed a unique approach to generate proliferative cells with a pre-CM phenotype that can be expanded in vitro to yield substantial cell doses.

METHODS

Cardiac fibroblasts were reprogrammed toward CM fate using lentiviral transduction of cardiac transcriptions factors (GATA4, MEF2C, TBX5, and MYOCD). The resulting cellular phenotype was analyzed by RNA sequencing and immunocytology. Live target cells were purified based on intracellular CM marker expression using molecular beacon technology and fluorescence-activated cell sorting. CM commitment was assessed using 5-azacytidine-based differentiation assays and the therapeutic effect was evaluated in a mouse model of acute myocardial infarction using echocardiography and histology. The cellular secretome was analyzed using mass spectrometry.

RESULTS

We found that proliferative CM precursor-like cells were part of the phenotype spectrum arising during direct reprogramming of fibroblasts toward CMs. These induced CM precursors (iCMPs) expressed CPC- and CM-specific proteins and were selectable via hairpin-shaped oligonucleotide hybridization probes targeting Myh6/7-mRNA-expressing cells. After purification, iCMPs were capable of extensive expansion, with preserved phenotype when under ascorbic acid supplementation, and gave rise to CM-like cells with organized sarcomeres in differentiation assays. When transplanted into infarcted mouse hearts, iCMPs prevented CM loss, attenuated fibrotic scarring, and preserved ventricular function, which can in part be attributed to their substantial secretion of factors with documented beneficial effect on cardiac repair.

CONCLUSIONS

Fibroblast reprogramming combined with molecular beacon-based cell selection yields an iCMP-like cell population with cardioprotective potential. Further studies are needed to elucidate mechanism-of-action and translational potential.

The Role of Galectin-3 in Heart Failure-The Diagnostic, Prognostic and Therapeutic Potential-Where Do We Stand?

Heart failure (HF) is a clinical syndrome with high morbidity and mortality, and its prevalence is rapidly increasing. Galectin-3 (Gal-3) is an important factor in the pathophysiology of HF, mainly due to its role in cardiac fibrosis, inflammation, and ventricular remodeling. Fibrosis is a hallmark of cardiac remodeling, HF, and atrial fibrillation development. This review aims to explore the involvement of Gal-3 in HF and its role in the pathogenesis and clinical diagnostic and prognostic significance. We report data on Gal-3 structure and molecular mechanisms of biological function crucial for HF development. Over the last decade, numerous studies have shown an association between echocardiographic and CMR biomarkers in HF and Gal-3 serum concentration. We discuss facts and concerns about Gal-3's utility in acute and chronic HF with preserved and reduced ejection fraction for diagnosis, prognosis, and risk stratification. Finally, we present attempts to use Gal-3 as a therapeutic target in HF.

Circulating Galectin-3 in Patients with Cardiogenic Shock Complicating Acute Myocardial Infarction Treated with Mild Hypothermia: A Biomarker Sub-Study of the SHOCK-COOL Trial

Background: Galectin-3 (Gal-3) is considered a potential cardiovascular inflammatory marker that may provide additional risk stratification for patients with acute heart failure. It is unknown whether mild therapeutic hypothermia (MTH) impacts Gal-3 levels. Therefore, this biomarker study aimed to investigate the effect of MTH on Gal-3. Methods: In the randomized SHOCK-COOL trial, 40 patients with cardiogenic shock (CS) complicating acute myocardial infraction (AMI) were randomly assigned to the MTH (33 °C) or control group in a 1:1 ratio. Blood samples were collected on the day of admission/day 1, day 2, and day 3. Gal-3 level kinetics throughout these time points were compared between the MTH and control groups. Additionally, potential correlations between Gal-3 and clinical patient characteristics were assessed. Multiple imputations were performed to account for missing data. Results: In the control group, Gal-3 levels were significantly lower on day 3 than on day 1 (day 1 vs. day 3: 3.84 [IQR 2.04−13.3] vs. 1.79 [IQR 1.23−3.50] ng/mL; p = 0.049). Gal-3 levels were not significantly different on any day between the MTH and control groups (p for interaction = 0.242). Spearman’s rank correlation test showed no significant correlation between Gal-3 levels and sex, age, smoking, body mass index (BMI), and levels of creatine kinase-MB, creatine kinase, C-reactive protein, creatinine, and white blood cell counts (all p > 0.05). Patients with lower Gal-3 levels on the first day after admission demonstrated a higher risk of all-cause mortality at 30 days (hazard ratio, 2.67; 95% CI, 1.11−6.42; p = 0.029). In addition, Gal-3 levels on day 1 had a good predictive value for 30-day all-cause mortality with an area under the receiver operating characteristic curve of 0.696 (95% CI: 0.513−0.879), with an optimal cut-off point of less than 3651 pg/mL. Conclusions: MTH has no effect on Gal-3 levels in patients with CS complicating AMI compared to the control group. In addition, Gal-3 is a relatively stable biomarker, independent of age, sex, and BMI, and Gal-3 levels at admission might predict the risk of 30-day all-cause mortality.

The interplay of galectins-1, -3, and -9 in the immune-inflammatory response underlying cardiovascular and metabolic disease

Galectins are β-galactoside-binding proteins that bind and crosslink molecules via their sugar moieties, forming signaling and adhesion networks involved in cellular communication, differentiation, migration, and survival. Galectins are expressed ubiquitously across immune cells, and their function varies with their tissue-specific and subcellular location. Particularly galectin-1, -3, and -9 are highly expressed by inflammatory cells and are involved in the modulation of several innate and adaptive immune responses. Modulation in the expression of these proteins accompany major processes in cardiovascular diseases and metabolic disorders, such as atherosclerosis, thrombosis, obesity, and diabetes, making them attractive therapeutic targets. In this review we consider the broad cellular activities ascribed to galectin-1, -3, and -9, highlighting those linked to the progression of different inflammatory driven pathologies in the context of cardiovascular and metabolic disease, to better understand their mechanism of action and provide new insights into the design of novel therapeutic strategies.

Left Ventricular Remodeling after Myocardial Infarction: From Physiopathology to Treatment

Myocardial infarction (MI) is the leading cause of death and morbidity worldwide, with an incidence relatively high in developed countries and rapidly growing in developing countries. The most common cause of MI is the rupture of an atherosclerotic plaque with subsequent thrombotic occlusion in the coronary circulation. This causes cardiomyocyte death and myocardial necrosis, with subsequent inflammation and fibrosis. Current therapies aim to restore coronary flow by thrombus dissolution with pharmaceutical treatment and/or intravascular stent implantation and to counteract neurohormonal activation. Despite these therapies, the injury caused by myocardial ischemia leads to left ventricular remodeling; this process involves changes in cardiac geometry, dimension and function and eventually progression to heart failure (HF). This review describes the pathophysiological mechanism that leads to cardiac remodeling and the therapeutic strategies with a role in slowing the progression of remodeling and improving cardiac structure and function.

Regulation of wound healing and fibrosis by galectins

Galectins are a family of proteins with at least one carbohydrate-recognition domain. Galectins are present in various tissues and organs and participate in different physiological and pathological molecular reactions in vivo. Wound healing is the basic process of traumatic disease recovery. Wound healing involves three overlapping stages: inflammation, proliferation, and remodelling. Furthermore, a comparison of wound healing with the tumour microenvironment revealed that galectin plays a key role in the wound healing process. The current review describes the role of galectin in inflammation, angiogenesis, re-epithelialisation, and fibrous scar formation and evaluates its potential as a therapeutic drug for wounds.

Galectin-3 interferes with tissue repair and promotes cardiac dysfunction and comorbidities in a genetic heart failure model

Galectin-3, a biomarker for heart failure (HF), has been associated with myocardial fibrosis. However, its causal involvement in HF pathogenesis has been questioned in certain models of cardiac injury-induced HF. To address this, we used desmin-deficient mice (des-/-), a model of progressive HF characterized by cardiomyocyte death, spontaneous inflammatory responses sustaining fibrosis, and galectin-3 overexpression. Genetic ablation or pharmacological inhibition of galectin-3 led to improvement of cardiac function and adverse remodeling features including fibrosis. Over the course of development of des-/- cardiomyopathy, monitored for a period of 12 months, galectin-3 deficiency specifically ameliorated the decline in systolic function accompanying the acute inflammatory phase (4-week-old mice), whereas a more pronounced protective effect was observed in older mice, including the preservation of diastolic function. Interestingly, the cardiac repair activities during the early inflammatory phase were restored under galectin-3 deficiency by increasing the proliferation potential and decreasing apoptosis of fibroblasts, while galectin-3 absence modulated macrophage-fibroblast coupled functions and suppressed both pro-fibrotic activation of cardiac fibroblasts and pro-fibrotic gene expression in the des-/- heart. In addition, galectin-3 also affected the emphysema-like comorbid pathology observed in the des-/- mice, as its absence partially normalized lung compliance. Collectively galectin-3 was found to be causally involved in cardiac adverse remodeling, inflammation, and failure by affecting functions of cardiac fibroblasts and macrophages. In concordance with this role, the effectiveness of pharmacological inhibition in ameliorating cardiac pathology features establishes galectin-3 as a valid intervention target for HF, with additive benefits for treatment of associated comorbidities, such as pulmonary defects. Schematic illustrating top to bottom, the detrimental role of galectin-3 (Gal3) in heart failure progression: desmin deficiency-associated spontaneous myocardial inflammation accompanying cardiac cell death (reddish dashed border) is characterized by infiltration of macrophages (round cells) and up-regulation of Lgals3 (encoding secretable galectin-3, green) and detrimental macrophage-related genes (Ccr2 and Arg1). In this galectin-3-enriched milieu, the early up-regulation of profibrotic gene expression (Tgfb1, Acta2, Col1a1), in parallel to the suppression of proliferative activities and a potential of senescence induction by cardiac fibroblasts (spindle-like cells), collectively promote des-/- cardiac fibrosis and dysfunction establishing heart failure (left panel). Additionally, galectin-3+ macrophage-enrichment accompanies the development of emphysema-like lung comorbidities. In the absence of galectin-3 (right panel), the effect of macrophage-fibroblast dipole and associated events are modulated (grey color depicts reduced expression or activities) leading to attenuated cardiac pathology in the des-/-Lgals3-/- mice. Pulmonary comorbidities are also limited.

Prognostic Value of Serum Galectin-3 in Chronic Heart Failure: A Meta-Analysis

Objective

To evaluate the association between serum galectin-3 and all-cause death (ACD) and cardiovascular death (CVD) in patients with chronic heart failure (CHF).

Methods

The PubMed and Embase databases and Clinical Trials Registry (www.clinicaltrials.gov) were searched for studies with data on serum galectin-3 and ACD and CVD in CHF patients. The hazard ratios (HRs) of ACD and CVD were calculated and presented with 95% CIs. HRs were pooled using fixed effects or random effects models when appropriate. Sensitivity analysis, meta-regression and subgroup analysis were applied to find the origin of heterogeneity. Visual inspection of Begg's funnel plot and Egger's test were performed to assess the possibility publication bias.

Results

Pooled data included the results from 6,440 patients from 12 studies in the meta-analysis. Higher serum galectin-3 was associated with a higher risk of ACD (HR, 1.38; 95% CI, 1.14–1.67) and CVD (HR, 1.13; 95% CI, 1.02–1.25) in CHF patients. In the subgroup analyses, higher serum galectin-3 was associated with an increased risk of ACD in all subgroups. The pooled HR of the shorter follow-up group (1.78; 95% CI, 1.50–2.11) was significantly higher than the pooled HR of the longer follow-up group (1.15; 95% CI, 1.05–1.25). Sensitivity analysis of eliminating one study in each turn indicated that Koukoui et al.'s study had the largest influence on the risk of all-cause death. All-cause death publication bias was not detected (Pr>|z| = 0.35 for Begg's test and P>|t| = 0.15 for Egger's test).

Conclusions

Serum galectin-3 has prognostic value of both all-cause death and cardiovascular death in CHF. Serum galectin-3 could be useful for risk classification in patients with CHF.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=193399.

The Diagnostic and Therapeutic Potential of Galectin-3 in Cardiovascular Diseases

Galectin-3 plays a prominent role in chronic inflammation and has been implicated in the development of many disease conditions, including heart disease. Galectin-3, a regulatory protein, is elevated in both acute and chronic heart failure and is involved in the inflammatory pathway after injury leading to myocardial tissue remodelling. We discussed the potential utility of galectin-3 as a diagnostic and disease severity/prognostic biomarker in different cardio/cerebrovascular diseases, such as acute ischemic stroke, acute coronary syndromes, heart failure and arrhythmogenic cardiomyopathy. Over the last decade there has been a marked increase in the understanding the role of galectin-3 in myocardial fibrosis and inflammation and as a therapeutic target for the treatment of heart failure and myocardial infarction.

Galectin-3 Derived from HucMSC Exosomes Promoted Myocardial Fibroblast-to-Myofibroblast Differentiation Associated with β-catenin Upregulation

Background and Objectives

Galectin-3 promotes fibroblast-to-myofibroblast differentiation and facilitates injury repair. Previous studies have shown that exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-ex) promote the differentiation of myocardial fibroblasts into myofibroblasts under inflammatory environment. Whether hucMSC-ex derived Galectin-3 (hucMSC-ex-Galectin-3) plays an important role in fibroblast-to-myofibroblast differentiation is the focus of this study.

Methods and Results

Galectin-3 was knocked-down by siRNA in hucMSCs, and then exosomes were extracted. Fibroblasts were treated with LPS, LPS＋hucMSC-ex, LPS＋negative control-siRNA-ex (NC-ex), or LPS＋Galectin-3-siRNA-ex (si-ex) in vitro. The coronary artery of the left anterior descending (LAD) branch was permanently ligated, followed by intramyocardial injection with phosphate buffered saline(PBS), hucMSC-ex, hucMSC-NC-ex, or hucMSC-si-ex in vivo. Western blot, RT-PCR, and immunohistochemistry were used to detect the expression of markers related to fibroblast-to-myofibroblast differentiation and inflammatory factors. Migration and contraction functions of fibroblasts were evaluated using Transwell migration and collagen contraction assays, respectively. β-catenin expression was detected by western blot and immunofluorescence. The results showed that hucMSC-ex increased the protein expression of myofibroblast markers, anti-inflammatory factors, and β-catenin. HucMSC-ex also reduced the migration and promoted the contractility of fibroblasts. However, hucMSC-si-ex did not show these activities.

Conclusions

HucMSC-ex-Galectin-3 promoted the differentiation of cardiac fibroblasts into myofibroblasts in an inflammatory environment, which was associated with increased β-catenin levels.

Neurohumoral, cardiac and inflammatory markers in the evaluation of heart failure severity and progression

Heart failure is common in adult population, accounting for substantial morbidity and mortality worldwide. The main risk factors for heart failure are coronary artery disease, hypertension, obesity, diabetes mellitus, chronic pulmonary diseases, family history of cardiovascular diseases, cardiotoxic therapy. The main factor associated with poor outcome of these patients is constant progression of heart failure. In the current review we present evidence on the role of established and candidate neurohumoral biomarkers for heart failure progression management and diagnostics. A growing number of biomarkers have been proposed as potentially useful in heart failure patients, but not one of them still resembles the characteristics of the “ideal biomarker.” A single marker will hardly perform well for screening, diagnostic, prognostic, and therapeutic management purposes. Moreover, the pathophysiological and clinical significance of biomarkers may depend on the presentation, stage, and severity of the disease. The authors cover main classification of heart failure phenotypes, based on the measurement of left ventricular ejection fraction, including heart failure with preserved ejection fraction, heart failure with reduced ejection fraction, and the recently proposed category heart failure with mid-range ejection fraction. One could envisage specific sets of biomarker with different performances in heart failure progression with different left ventricular ejection fraction especially as concerns prediction of the future course of the disease and of left ventricular adverse/reverse remodeling. This article is intended to provide an overview of basic and additional mechanisms of heart failure progression will contribute to a more comprehensive knowledge of the disease pathogenesis.

Biomarkers of acute myocardial infarction: diagnostic and prognostic value. Part 2 (Literature review)

In the second part of the review, we continue the discussion of biomarkers that have a diagnostic and prognostic significance in acute myocardial infarction (AMI). The study of the AMI pathophysiology through the experimental and clinical research contributes to the discovery of new regulatory molecules and pathogenetic mechanisms underlying AMI. At the same time, many molecules involved in the pathogenesis of AMI can be used as effective biomarkers for the diagnosis and prediction of AMI. This article discusses in detail the diagnostic and prognostic value of inflammatory biomarkers of AMI (C-reactive protein, interleukin-6, tumor necrosis factor-alpha, myeloperoxidase, matrix metalloproteinases, soluble form of CD40 ligand, procalcitonin, placental growth factor) and a number of recently discovered new biomarkers of AMI (microribonucleic acids, galectin-3, stimulating growth factor expressed by gene 2, growth differentiation factor 15, proprotein convertase of subtilisin-kexin type 9).

Research progress on the role of gal-3 in cardio/cerebrovascular diseases

Galectin-3 (gal-3), a member of the galectin family, is a glycoprotein with high affinity for β-galactoside. Gal-3 is a cytoplasmically synthesized protein that can shuttle between the cytoplasm and nucleus and can even be transported to the membrane and secreted into the extracellular environment. Cardio/cerebrovascular diseases generally refer to ischemic or hemorrhagic diseases occurring in the heart, brain and systemic tissues, which are characterized by high morbidity, high disability rates and high mortality rates. To date, considerable research has demonstrated that gal-3 expression is aberrantly increased and plays important roles in cardio/cerebrovascular diseases, such as acute ischemic stroke (AIS), myocardial fibrosis, acute coronary syndrome (ACS), and heart failure (HF). Hence, understanding the biological roles of gal-3 in these diseases may be essential for cardio/cerebrovascular disease treatment and diagnosis to improve patient quality of life. In this review, we summarize current research on the roles of gal-3 in human cardiovascular diseases and potential inhibitors of gal-3, which may provide new strategies for disease therapies.

Post-Myocardial Infarction Ventricular Remodeling Biomarkers-The Key Link between Pathophysiology and Clinic

Studies in recent years have shown increased interest in developing new methods of evaluation, but also in limiting post infarction ventricular remodeling, hoping to improve ventricular function and the further evolution of the patient. This is the point where biomarkers have proven effective in early detection of remodeling phenomena. There are six main processes that promote the remodeling and each of them has specific biomarkers that can be used in predicting the evolution (myocardial necrosis, neurohormonal activation, inflammatory reaction, hypertrophy and fibrosis, apoptosis, mixed processes). Some of the biomarkers such as creatine kinase-myocardial band (CK-MB), troponin, and N-terminal-pro type B natriuretic peptide (NT-proBNP) were so convincing that they immediately found their place in the post infarction patient evaluation protocol. Others that are related to more complex processes such as inflammatory biomarkers, atheroma plaque destabilization biomarkers, and microRNA are still being studied, but the results so far are promising. This article aims to review the markers used so far, but also the existing data on new markers that could be considered, taking into consideration the most important studies that have been conducted so far.

Value of Galectin-3 in Acute Myocardial Infarction

Galectins are an ancient family of lectins characterized by evolutionarily conserved amino acid sequences and β-galactoside recognition and binding sites. Galectin-3 (Gal-3) is one of 15 known galectins. This protein has important functions in numerous biological activities, including cardiac fibrosis and heart failure. In recent years, many studies have shown that Gal-3 is closely associated with acute myocardial infarction (AMI) and may be a promising biomarker for the assessment of severity as well as prognosis prediction in AMI patients, but controversy still exists. In this review, we summarize the latest literature on the relationship between Gal-3 and unstable plaques, the secretion kinetics of Gal-3 during the acute phase of AMI, and the value of Gal-3 in the prediction of post-AMI remodeling. Finally, the possible value of Gal-3 as a biological target for AMI therapy is examined.

Galectin-3 as the Prognostic Factor of Adverse Cardiovascular Events in Long-Term Follow up in Patients after Myocardial Infarction-A Pilot Study

Galectin-3 (Gal-3) is a new independent risk factor in the development and severity of coronary artery disease (CAD). The aim of the study was to evaluate whether Gal-3 concentration has prognostic value and if it reflects the progression of atherosclerosis in carotid arteries in patients with CAD after acute myocardial infarction (AMI). The analysis included 110 patients who were hospitalized due to AMI, treated with primary coronary intervention (PCI) and further attended a follow-up visit, and 100 healthy volunteers. The Gal-3 concentration and carotid ultrasound were evaluated at baseline and on a follow-up visit. We found that the Gal-3 concentration in the group with hyperlipidemia decreased during the observation (10.7 vs. 7.9 ng/mL, p = 0.00003). Patients rehospitalized during follow up had higher concentration of Gal-3 in the acute phase of myocardial infarction (MI) (10.7 vs. 7.2 ng/mL, p = 0.02; 10.1 vs. 8.0 ng/mL, p = 0.002, respectively). In the group of patients who had none of the following endpoints: subsequent MI, PCI, coronary artery bypass grafting (CABG) or stroke, there was a decrease in Gal-3 concentration at the follow-up visit. Parameters affecting the frequency of a composite endpoint occurrence are: the presence of atheromatous plaque in the carotid artery (p = 0.017), Gal-3 (p = 0.004) and haemoglobin (p = 0.03) concentration. In multivariate analysis, only Gal-3 concentration higher than 9.2 ng/mL at discharge was associated with a nine-fold increase of risk of composite endpoint occurrence (p = 0.0005, OR = 9.47, 95% CI 2.60–34.45). A significant decrease in Gal-3 concentration was observed in the group of patients after AMI without the endpoint occurrence during observation.

Genetic Deletion of Galectin-3 Alters the Temporal Evolution of Macrophage Infiltration and Healing Affecting the Cardiac Remodeling and Function after Myocardial Infarction in Mice

We studied the role of galectin-3 (Gal-3) in the expression of alternative activation markers (M2) on macrophage, cytokines, and fibrosis through the temporal evolution of healing, ventricular remodeling, and function after myocardial infarction (MI). C57BL/6J and Gal-3 knockout mice (Lgals3^-/-) were subjected to permanent coronary ligation or sham. We studied i) mortality, ii) macrophage infiltration and expression of markers of alternative activation, iii) cytokine, iv) matrix metalloproteinase-2 activity, v) fibrosis, and vi) cardiac function and remodeling. At 1 week post-MI, lack of Gal-3 markedly attenuated F4/80+ macrophage infiltration and significantly increased the expression of Mrc1 and Chil1, markers of M2 macrophages at the MI zone. Levels of IL-10, IL-6, and matrix metalloproteinase-2 were significantly increased, whereas tumor necrosis factor-α, transforming growth factor-β, and fibrosis were remarkably attenuated at the infarct zone. In Gal-3 knockout mice, scar thinning ratio, expansion, and cardiac remodeling and function were severely affected from the onset of MI. At 4 weeks post-MI, the natural evolution of fibrosis in Gal-3 knockout mice was also affected. Our results suggest that Gal-3 is essential for wound healing because it regulates the dynamics of macrophage infiltration, proinflammatory and anti-inflammatory cytokine expression, and fibrosis along the temporal evolution of MI in mice. The deficit of Gal-3 affected the dynamics of wound healing, thus aggravating the evolution of remodeling and function.

Galectin-3 Is Associated with Cardiovascular Events in Post-Acute Coronary Syndrome Patients with Type-2 Diabetes

Introduction: Type-2 diabetes mellitus (T2DM) is associated with early and severe atherosclerosis. However, few biomarkers can predict cardiovascular events in this population. Methods: We followed 964 patients with coronary artery disease (CAD), assessing plasma levels of galectin-3, monocyte chemoattractant protein-1 (MCP-1), and N-terminal fragment of brain natriuretic peptide (NT-proBNP) at baseline. The secondary outcomes were acute ischemia and heart failure or death. The primary outcome was the combination of the secondary outcomes. Results. Two hundred thirty-two patients had T2DM. Patients with T2DM showed higher MCP-1 (144 (113–195) vs. 133 (105–173) pg/mL, p = 0.006) and galectin-3 (8.3 (6.5–10.5) vs. 7.8 (5.9–9.8) ng/mL, p = 0.049) levels as compared to patients without diabetes. Median follow-up was 5.39 years (2.81–6.92). Galectin-3 levels were associated with increased risk of the primary outcome in T2DM patients (Hazard ratio (HR) 1.57 (1.07–2.30); p = 0.022), along with a history of cerebrovascular events. Treatment with clopidogrel was associated with lower risk. In contrast, NT-proBNP and MCP-1, but not galectin-3, were related to increased risk of the event in nondiabetic patients (HR 1.21 (1.04–1.42); p = 0.017 and HR 1.23 (1.05–1.44); p = 0.012, respectively), along with male sex and age. Galectin-3 was also the only biomarker associated with the development of acute ischemic events and heart failure or death in T2DM patients, while, in nondiabetics, MCP-1 and NT-proBNP, respectively, were related to these events. Conclusion: In CAD patients, galectin-3 plasma levels are associated with cardiovascular events in patients with T2DM, and MCP-1 and NT-proBNP in those without T2DM.

Tolerogenic Dendritic Cells Reduce Cardiac Inflammation and Fibrosis in Chronic Chagas Disease

Chronic Chagas disease cardiomyopathy (CCC) is the most frequent and severe form of this parasitic disease. CCC is caused by a progressive inflammation in the heart, resulting in alterations that can culminate in heart failure and death. The use of dendritic cells (DCs) appears as an option for the development of treatments due to their important role in regulating immune responses. Here, we investigated whether tolerogenic cells (tDCs) could interfere with the progression of CCC in an experimental model of Chagas disease. The tDCs were generated and characterized as CD11b⁺ CD11c⁺ cells, low expression of MHC-II, CD86, CD80, and CD40, and increased expression of PD-L. These cells produced low levels of IL-6 and IL-12p70 and higher levels of IL-10, compared to mature DCs (mDCs). Interestingly, tDCs inhibited lymphoproliferation and markedly increased the population of FoxP3⁺ Treg cells in vitro, compared to mature DCs. In a mouse model of CCC, treatment with tDCs reduced heart inflammation and fibrosis. Furthermore, tDCs treatment reduced the gene expression of pro-inflammatory cytokines (Ifng and Il12) and of genes related to cardiac remodeling (Col1a2 and Lgals3), while increasing the gene expression of IL-10. Finally, administration of tDCs, increased the percentage of Treg cells in the hearts and spleens of chagasic mice. Ours results show that tolerogenic dendritic cells have therapeutic potential on CCC, inhibiting disease progression.

IL (Interleukin)-10-STAT3-Galectin-3 Axis Is Essential for Osteopontin-Producing Reparative Macrophage Polarization After Myocardial Infarction

BACKGROUND

Both osteopontin (OPN) and galectin-3 have been implicated in phagocytic clearance of dead cells and reparative fibrosis during wound healing. CD206⁺ macrophages are involved in tissue repair through phagocytosis and fibrosis after myocardial infarction (MI). However, the relationship among OPN, galectin-3, and macrophage polarization in the context of MI remains unclear.

METHODS

The time course of Spp1 (encoding OPN) expression in the heart after MI showed a strong activation of Spp1 on day 3 after MI. To identify where in the body and in which cells the transcriptional activity of Spp1 increased after MI, we analyzed EGFP (enhanced green fluorescent protein)- Spp1 knockin reporter mice on day 3 after MI.

RESULTS

The transcriptional activity of Spp1 increased only in CD206⁺ macrophages in the infarct myocardium, and most of CD206⁺ macrophages have strong transcriptional activation of Spp1 after MI. The temporal expression pattern of Lgal3 (encoding galectin-3) in cardiac macrophages after MI was similar to that of Spp1, and OPN is almost exclusively produced by galectin-3^hiCD206⁺ macrophages. Although both interleukin (IL)-4 and IL-10 were reported to promote CD206⁺ macrophage-mediated cardiac repair after MI, IL-10- but not IL-4-stimulated CD11b⁺Ly6G^- cells could differentiate into OPN-producing galectin-3^hiCD206⁺ macrophages and showed enhanced phagocytic ability. Inhibition of STAT3 tyrosine phosphorylation suppressed IL-10-induced expression of intracellular galectin-3 and transcriptional activation of Spp1. Knockdown of galectin-3 suppressed their ability to differentiate into OPN-producing cells, but not STAT3 activation. The tyrosine phosphorylation of STAT3 and the appearance rate of galectin-3^hiCD206⁺ cells on cardiac CD11b⁺Ly6G^- cells in Spp1 knockout mice were the same as those in wild-type mice. Spp1 knockout mice showed vulnerability to developing post-MI left ventricular chamber dilatation and the terminal deoxynucleo-tidyltransferase 2'-Deoxyuridine-5'-triphosphate nick-end labeling (TUNEL)-positive cells in the infarcted myocardium after MI remained higher in number in Spp1 knockout mice than in wild-type mice.

CONCLUSIONS

OPN is almost exclusively produced by galectin-3^hiCD206⁺ macrophages, which specifically appear in the infarct myocardium after MI. The IL-10-STAT3-galectin-3 axis is essential for OPN-producing reparative macrophage polarization after myocardial infarction, and these macrophages contribute to tissue repair by promoting fibrosis and clearance of apoptotic cells. These results suggest that galectin-3 may contribute to reparative fibrosis in the infarct myocardium by controlling OPN levels.

Association between Galectin-3 levels within central and peripheral venous blood, and adverse left ventricular remodelling after first acute myocardial infarction

Our study investigates association between Galectin-3 levels and adverse left ventricular remodelling (LVR) at six months. Fifty-seven patients following first acute myocardial infarction (AMI) were enrolled in this study and blood samples collected on day 1 from the femoral vein and artery, the right atrium near the coronary sinus and the aortic root, and on day 30, from the cubital vein. Patients with LVESV ≥20% at six months, were included in the LVR group. On day 1, Galectin-3 plasma levels in the femoral vein (10.34 ng/ml ± 3.81 vs 8.22 ng/ml ± 2.34, p = 0.01), and near coronary sinus (10.7 ng/ml ± 3.97 vs 8.41 ng/ml ± 2.56, p = 0.007) were higher in the LVR group. Positive correlations between Galectin-3 levels from aortic root and coronary sinus, aortic root and femoral vein, and coronary sinus and femoral vein, were observed in both groups. On day 30, Galectin-3 concentration in the cubital vein was an independent risk factor of LVR six months post-AMI, demonstrating 1.5-fold increased risk. Day-30 Galectin-3 also showed positive correlations with echocardiography parameters indicative of diastolic and systolic dysfunction. Determining Galectin-3 plasma concentration on day 30 following AMI could have beneficial prognostic value in predicting LVR.

Fibroblast growth factor 21 protects against pathological cardiac remodeling by modulating galectin-3 expression

BACKGROUND/AIMS

Fibroblast growth factor 21 (FGF21) plays a protective role in ischemia/reperfusion induced cardiac injury. However, the exact molecular mechanism of FGF21 action remains unclear. This study was designed the protective effect of FGF21 on the heart and its mechanism.

METHOD

Adenovirus vector expressing FGF21 or control β-galactosidase was injected into the myocardium of mice. Myocardial injury was observed by tissue staining and immunohistochemical staining. The expression level of caspases-3 and galectin-3 in myocardial cells were observed by immunoblotting. Then, hypoxia-induced cell model was established. Small interfering RNA (SiRNA) and plasmid were transfected into H9c2 using Lipofectamine 2000 reagent (Invitrogen). The expression levels of galectin-3, ECM and cystatin-3 in cells were observed by immunoblotting, and the relationship between fibroblast growth factor 21 and galectin-3 was analyzed.

RESULT

Cell test in vitro showed that FGF21 could inhibit apoptosis and decrease the expression of ECM (ColIaI, fibronectin, and alpha-SMA) under hypoxia. Western blot data showed that hypoxia-induced cell damage increased galectin-3 levels, while FGF21 decreased galactose lectin-3 levels. In addition, inhibition of galactose agglutinin-3 expression by siRNA enhanced the cardioprotective effect of FGF21, while overexpression of galectin-3 reduced the cardioprotective effect of fibroblast growth factor 21.

CONCLUSION

FGF21 may be a novel therapy for hypoxia-induced cardiac injury by regulating the expression of galectin-3.

Myocardial Injury After Ischemia/Reperfusion Is Attenuated By Pharmacological Galectin-3 Inhibition

Although optimal therapy for myocardial infarction includes reperfusion to restore blood flow to the ischemic region, ischemia/reperfusion (IR) also initiates an inflammatory response likely contributing to adverse left ventricular (LV) extracellular matrix (ECM) remodeling. Galectin-3 (Gal-3), a β-galactoside-binding-lectin, promotes cardiac remodeling and dysfunction. Our aim is to investigate whether Gal-3 pharmacological inhibition using modified citrus pectin (MCP) improves cardiac remodeling and functional changes associated with IR. Wistar rats were treated with MCP from 1 day before until 8 days after IR (coronary artery ligation) injury. Invasive hemodynamics revealed that both LV contractility and LV compliance were impaired in IR rats. LV compliance was improved by MCP treatment 8 days after IR. Cardiac magnetic resonance imaging showed decreased LV perfusion in IR rats, which was improved with MCP. There was no difference in LV hypertrophy in MCP-treated compared to untreated IR rats. However, MCP treatment decreased the ischemic area as well as Gal-3 expression. Gal-3 blockade paralleled lower myocardial inflammation and reduced fibrosis. These novel data showing the benefits of MCP in compliance and ECM remodeling in IR reinforces previously published data showing the therapeutic potential of Gal-3 inhibition.

β-Adrenoceptor activation affects galectin-3 as a biomarker and therapeutic target in heart disease

Myocardial fibrosis is a key histopathological component that drives the progression of heart disease leading to heart failure and constitutes a therapeutic target. Recent preclinical and clinical studies have implicated galectin-3 (Gal-3) as a pro-fibrotic molecule and a biomarker of heart disease and fibrosis. However, our knowledge is poor on the mechanism(s) that determine the blood level or regulate cardiac expression of Gal-3. Recent studies have demonstrated that enhanced β-adrenoceptor activity is a determinant of both circulating concentration and cardiac expression of Gal-3. Pharmacological or transgenic activation of β-adrenoceptors leads to increased blood levels of Gal-3 and up-regulated cardiac Gal-3 expression, effect that can be reversed with the use of β-adrenoceptor antagonists. Conversely, Gal-3 gene deletion confers protection against isoprenaline-induced cardiotoxicity and fibrogenesis. At the transcription level, β-adrenoceptor stimulation activates cardiac mammalian sterile-20-like kinase 1, a pivotal kinase of the Hippo signalling pathway, which is associated with Gal-3 up-regulation. Recent studies have suggested a role for the β-adrenoceptor-Hippo signalling pathway in the regulation of cardiac Gal-3 expression thereby contributing to the onset and progression of heart disease. This implies a therapeutic potential of the suppression of Gal-3 expression. In this review, we discuss the effects of β-adrenoceptor activity on Gal-3 as a biomarker and causative mediator in the setting of heart disease and point out pivotal knowledge gaps. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.

Galectin 3 and Galectin 3 Binding Protein Improve the Risk Stratification after Myocardial Infarction

Background: Acute myocardial infarction (AMI) survivors are at risk of major adverse cardiac events and their risk stratification is a prerequisite to tailored therapeutic approaches. Biomarkers could be of great utility in this setting. Methods: We sought to evaluate the utility of the combined assessment of Galectin 3 (Gal-3) and Galectin 3 binding protein (Gal-3bp) for post-AMI risk stratification in a large, consecutive population of AMI patients. The primary outcomes were: Recurrent angina/AMI and all-cause mortality at 12 months after the index event. Results: In total, 469 patients were included. The median Gal-3bp was 9.1 μg/mL (IQR 5.8–13.5 μg/mL), while median Gal-3 was 9.8 ng/mL (IQR 7.8–12.8 ng/mL). During the 12 month follow-up, 34 patients died and 41 had angina pectoris/reinfarction. Gal-3 was associated with all-cause mortality, while Gal-3bp correlated with the risk of angina/myocardial infarction even when corrected for other significant covariates. The final multivariable model for mortality prediction included patients’ age, left ventricular ejection fraction (LVEF), Gal-3, and renal function. The ROC curve estimated for this model has an area under the curve (AUC) of 0.84 (95%CI 0.78–0.9), which was similar to the area under the ROC curve obtained using the GRACE score 1-year mortality. Conclusions: The integrated assessment of Gal-3 and Gal-3bp could be helpful in risk stratification after AMI.

Diagnostic and prognostic value of biomarkers in acute myocardial infarction

The incidence of acute myocardial infarction (AMI) has been increasing rapidly in recent years, seriously endangering human health. Cardiac biomarkers play critical roles in the diagnosis and prognosis of AMI. Troponin is a highly sensitive and specific biomarker for AMI diagnosis and can independently predict adverse cardiac events. Other biomarkers such as N-terminal B-type natriuretic peptide and C reactive protein are also valuable predictors of cardiovascular prognosis. Recently, several novel biomarkers have been identified for the diagnosis and risk assessment in patients with AMI. A multibiomarker approach can potentially enhance the diagnostic accuracy and provide more information for the early risk stratification of AMI. In this review, we will summarise the biomarkers discovered in recent years and focus on their diagnostic and prognostic value for patients with AMI.

Molecular discoveries and treatment strategies by direct reprogramming in cardiac regeneration

Cardiac tissue has minimal endogenous regenerative capacity in response to injury. Treatment options are limited following tissue damage after events such as myocardial infarction. Current strategies are aimed primarily at injury prevention, but attention has been increasingly targeted toward the development of regenerative therapies. This review focuses on recent developments in the field of cardiac fibroblast reprogramming into induced cardiomyocytes. Early efforts to produce cardiac regeneration centered around induced pluripotent stem cells, but clinical translation has proved elusive. Currently, techniques are being developed to directly transdifferentiate cardiac fibroblasts into induced cardiomyocytes. Viral vector-driven expression of a combination of transcription factors including Gata4, Mef2c, and Tbx5 induced cardiomyocyte development in mice. Subsequent combinational modifications have extended these results to human cell lines and increased efficacy. The miRNAs including combinations of miR-1, miR-133, miR-208, and miR-499 can improve or independently drive regeneration of cardiomyocytes. Similar results could be obtained by combinations of small molecules with or without transcription factor or miRNA expression. The local tissue environment greatly impacts favorability for reprogramming. Modulation of signaling pathways, especially those mediated by VEGF and TGF-β, enhance differentiation to cardiomyocytes. Current reprogramming strategies are not ready for clinical application, but recent breakthroughs promise regenerative cardiac therapies in the near future.

Galectin-3 deficiency ameliorates fibrosis and remodeling in dilated cardiomyopathy mice with enhanced Mst1 signaling

Dilated cardiomyopathy (DCM) is a major cause of heart failure without effective therapy. Fibrogenesis plays a key role in the development of DCM, but little is known of the expression of the profibrotic factor galectin-3 (Gal-3) and its role in DCM pathophysiology. In a mouse DCM model with transgenic (TG) overexpression of mammalian sterile 20-like kinase 1 (Mst1), we studied Gal-3 expression and effects of the Gal-3 inhibitor modified citrus pectin (MCP) or Gal-3 gene knockout (KO). Gal-3 deletion in TG mice (TG/KO) was achieved by crossbreeding Mst1-TG mice with Gal-3 KO mice. The DCM phenotype was assessed by echocardiography and micromanometry. Cardiac expression of Gal-3 and fibrosis were determined. The cardiac transcriptome was profiled by RNA sequencing. Mst1-TG mice at 3-8 mo of age exhibited upregulated expression of Gal-3 by ~40-fold. TG mice had dilatation of cardiac chambers, suppressed left ventricular (LV) ejection fraction, poor LV contractility and relaxation, a threefold increase in LV collagen content, and upregulated fibrotic genes. Four-month treatment with MCP showed no beneficial effects. Gal-3 deletion in Mst1-TG mice attenuated chamber dilatation, organ congestion, and fibrogenesis. RNA sequencing identified profound disturbances by Mst1 overexpression in the cardiac transcriptome, which largely remained in TG/KO hearts. Gal-3 deletion in Mst1-TG mice, however, partially reversed the dysregulated transcriptional signaling involving extracellular matrix remodeling and collagen formation. We conclude that cardiac Mst1 activation leads to marked Gal-3 upregulation and transcriptome disturbances in the heart. Gal-3 deficiency attenuated cardiac remodeling and fibrotic signaling. NEW & NOTEWORTHY We found in a transgenic mouse dilated cardiomyopathy (DCM) model a pronounced upregulation of galectin-3 in cardiomyocytes. Galectin-3 gene deletion reduced cardiac fibrosis and fibrotic gene profiles and ameliorated cardiac remodeling and dysfunction. These benefits of galectin-3 deletion were in contrast to the lack of effect of treatment with the galectin-3 inhibitor modified citrus pectin. Our study suggests that suppression of galectin-3 mRNA expression could be used to treat DCM with high cardiac galectin-3 content.

Left ventricular remodeling after the first myocardial infarction in association with LGALS-3 neighbouring variants rs2274273 and rs17128183 and its relative mRNA expression: a prospective study

Post-infarct left ventricular remodeling (LVR) process increases the risk of heart failure (HF). Circulating galectin-3 has been associated with fibrosis, inflammation and cardiac dysfunction during the remodeling process after myocardial infarction (MI). The aims of this prospective case study were to investigate the association of potentially functional variants in the vicinity of LGALS-3 locus, rs2274273 and rs17128183 with maladaptive LVR and whether these variants could affect LGALS-3 mRNA expression in peripheral blood mononuclear cells of patients 6 months after the first MI. This study encompassed 167 patients with acute MI that were followed up for 6 months. Evidence of LVR was obtained by repeated 2D Doppler echocardiography. Rs2274273, rs17128183 and LGALS-3 mRNA expression were detected by TaqMan^® technology. Rs2274273 and rs17128183 rare allele bearing genotypes, according to the dominant model (CT+TT vs. CC and AG+GG vs. AA, respectively), were significantly and independently associated with maladaptive LVR (adjusted OR = 3.02, P = 0.016; adjusted OR = 3.14, P = 0.019, respectively) and higher LGALS-3 mRNA expression (fold induction 1.203, P = 0.03 and 1.214, P = 0.03, respectively). Our exploratory results suggest that rs2274273 and rs17128183 variants affect LGALS-3 mRNA and bear the risk for maladaptive LVR post-MI remodeling. Further replication and validation in a larger group of patients is inevitable.

Upregulated galectin-3 is not a critical disease mediator of cardiomyopathy induced by β2-adrenoceptor overexpression

Preclinical studies have demonstrated that anti-galectin-3 (Gal-3) interventions are effective in attenuating cardiac remodeling, fibrosis, and dysfunction. We determined, in a transgenic (TG) mouse model of fibrotic cardiomyopathy, whether Gal-3 expression was elevated and whether Gal-3 played a critical role in disease development. We studied mice with fibrotic cardiomyopathy attributable to cardiac overexpression of human β2-adrenoceptors (β2-TG). Cardiac expression levels of Gal-3 and fibrotic or inflammatory genes were determined. The effect of Gal-3 inhibition in β2-TG mice was studied by treatment with Gal-3 inhibitors ( N-acetyllactosamine and modified citrus pectin) or by deletion of Gal-3 through crossing β2-TG and Gal-3 knockout mice. Changes in cardiomyopathy phenotypes were assessed by echocardiography and biochemical assays. In β2-TG mice at 3, 6, and 9 mo of age, upregulation of Gal-3 expression was observed at mRNA (~6- to 15-fold) and protein (~4- to 8-fold) levels. Treatment of β2-TG mice with N-acetyllactosamine (3 wk) or modified citrus pectin (3 mo) did not reverse cardiac fibrosis, inflammation, and cardiomyopathy. Similarly, Gal-3 gene deletion in β2-TG mice aged 3 and 9 mo did not rescue the cardiomyopathy phenotype. In conclusion, the β2-TG model of cardiomyopathy showed a robust upregulation of Gal-3 that correlated with disease severity, but Gal-3 inhibitors or Gal-3 gene deletion had no effect in halting myocardial fibrosis, remodeling, and dysfunction. Gal-3 may not be critical for cardiac fibrogenesis and remodeling in this cardiomyopathy model.

NEW & NOTEWORTHY We showed a robust upregulation of cardiac galectin-3 (Gal-3) expression in a mouse model of cardiomyopathy attributable to cardiomyocyte-restricted transgenic activation of β2-adrenoceptors. However, pharmacological and genetic inhibition of Gal-3 did not confer benefit in this model, implying that Gal-3 may not be a critical disease mediator of cardiac remodeling in this model.

Galectin-3 regulation of wound healing and fibrotic processes: insights for chronic skin wound therapeutics

A member of the lectin family, galectin-3 is a 250 amino-acid protein that contains a C-terminus carbohydrate recognition domain (CRD) that recognizes β-galactosides. Considered to have certain common properties associated with matricellular proteins, galectin-3 is expressed in the dermis and epidermis in healthy skin and is upregulated in skin healing, peaking at day 1 post wounding in mice. Galectin-3 has been implicated in several processes central to the wound healing response, specifically in the regulation of inflammation, macrophage polarization, angiogenesis, fibroblast to myofibroblast transition and re-epithelialization. However, it appears that many of the effects of Galectin-3 are highly tissue specific and context dependent. Genetic deletion of galectin-3 shows different effects in skin compared to lung, heart, and kidney remodeling. In this review, we will compare galectin-3 functions in these tissues. Furthermore, we will discuss, based on its identified regulation of cell processes, whether in an exogenous form, galectin-3 could represent a novel therapeutic for impaired skin healing.

Galectin-3 Activation and Inhibition in Heart Failure and Cardiovascular Disease: An Update

Galectin-3 is a versatile protein orchestrating several physiological and pathophysiological processes in the human body. In the last decade, considerable interest in galectin-3 has emerged because of its potential role as a biotarget. Galectin-3 is differentially expressed depending on the tissue type, however its expression can be induced under conditions of tissue injury or stress. Galectin-3 overexpression and secretion is associated with several diseases and is extensively studied in the context of fibrosis, heart failure, atherosclerosis and diabetes mellitus. Monomeric (extracellular) galectin-3 usually undergoes further "activation" which significantly broadens the spectrum of biological activity mainly by modifying its carbohydrate-binding properties. Self-interactions of this protein appear to play a crucial role in regulating the extracellular activities of this protein, however there is limited and controversial data on the mechanisms involved. We therefore summarize (recent) literature in this area and describe galectin-3 from a binding perspective providing novel insights into mechanisms by which galectin-3 is known to be "activated" and how such activation may be regulated in pathophysiological scenarios.

Understanding cardiac extracellular matrix remodeling to develop biomarkers of myocardial infarction outcomes

Cardiovascular Disease (CVD) is the most common cause of death in industrialized countries, and myocardial infarction (MI) is a major CVD with significant morbidity and mortality. Following MI, the left ventricle (LV) undergoes a wound healing response to ischemia that results in extracellular matrix (ECM) scar formation to replace necrotic myocytes. While ECM accumulation following MI is termed cardiac fibrosis, this is a generic term that does not differentiate between ECM accumulation that occurs in the infarct region to form a scar that is structurally necessary to preserve left ventricle (LV) wall integrity and ECM accumulation that increases LV wall stiffness to exacerbate dilation and stimulate the progression to heart failure. This review focuses on post-MI LV ECM remodeling, targeting the discussion on ECM biomarkers that could be useful for predicting MI outcomes.

The Association between Galectin-3 and hs-CRP and the Clinical Outcome after Non-ST-Elevation Myocardial Infarction with Preexisting Atrial Fibrillation

Increased galectin-3 plasma concentration has been linked to an unfavorable outcome in patients with heart failure or atrial fibrillation (AF). There are no published data about the prognostic utility of galectin-3 and high-sensitivity C-reactive protein (hs-CRP) for long-term clinical outcome in the Non-ST elevation acute myocardial infarction (NSTEMI) patients with preexisting AF. Thirty-two patients with the first acute NSTEMI and preexisting AF and 22 patients without preexisting AF, were prospectively followed for fifteen months. Patients with AF had significantly higher galectin-3 plasma levels (p < 0.05) and hs-CRP concentration (p < 0.01), compared with patients without AF. Galectin-3 plasma concentration was not a significant covariate of the composite outcomes (p = 0.913). Patients with high hs-CRP (above 4.55 mg/L) showed 2.5 times increased risk (p < 0.05) of the composite outcome occurrence (p < 0.05). Besides, three-vessel coronary artery disease, creatinine serum level, and creatinine clearance were significant covariates (p < 0.05; p < 0.05; p < 0.01) of the composite outcome, respectively. Creatinine clearance, solely, has been shown to be an independent predictor of unfavorable prognosis after a 15-month follow-up. Galectin-3 and hs-CRP plasma levels were elevated in NSTEMI patients with AF, but with differential predictive value for an unfavorable clinical outcome. Only hs-CRP was associated with increased risk of composite outcome occurrence.

Efferocytosis and Outside-In Signaling by Cardiac Phagocytes. Links to Repair, Cellular Programming, and Intercellular Crosstalk in Heart

Phagocytic sensing and engulfment of dying cells and extracellular bodies initiate an intracellular signaling cascade within the phagocyte that can polarize cellular function and promote communication with neighboring non-phagocytes. Accumulating evidence links phagocytic signaling in the heart to cardiac development, adult myocardial homeostasis, and the resolution of cardiac inflammation of infectious, ischemic, and aging-associated etiology. Phagocytic clearance in the heart may be carried out by professional phagocytes, such as macrophages, and non-professional cells, including myofibrolasts and potentially epithelial cells. During cardiac development, phagocytosis initiates growth cues for early cardiac morphogenesis. In diseases of aging, including myocardial infarction, heightened levels of cell death require efficient phagocytic debridement to salvage further loss of terminally differentiated adult cardiomyocytes. Additional risk factors, including insulin resistance and other systemic risk factors, contribute to inefficient phagocytosis, altered phagocytic signaling, and delayed cardiac inflammation resolution. Under such conditions, inflammatory presentation of myocardial antigen may lead to autoimmunity and even possible rejection of transplanted heart allografts. Increased understanding of these basic mechanisms offers therapeutic opportunities.

From Inflammation to Fibrosis-Molecular and Cellular Mechanisms of Myocardial Tissue Remodelling and Perspectives on Differential Treatment Opportunities

PURPOSE OF REVIEW

In this review, we highlight the most important cellular and molecular mechanisms that contribute to cardiac inflammation and fibrosis. We also discuss the interplay between inflammation and fibrosis in various precursors of heart failure (HF) and how such mechanisms can contribute to myocardial tissue remodelling and development of HF.

RECENT FINDINGS

Recently, many research articles attempt to elucidate different aspects of the interplay between inflammation and fibrosis. Cardiac inflammation and fibrosis are major pathophysiological mechanisms operating in the failing heart, regardless of HF aetiology. Currently, novel therapeutic options are available or are being developed to treat HF and these are discussed in this review. A progressive disease needs an aggressive management; however, existing therapies against HF are insufficient. There is a dynamic interplay between inflammation and fibrosis in various precursors of HF such as myocardial infarction (MI), myocarditis and hypertension, and also in HF itself. There is an urgent need to identify novel therapeutic targets and develop advanced therapeutic strategies to combat the syndrome of HF. Understanding and describing the elements of the inflammatory and fibrotic pathways are essential, and specific drugs that target these pathways need to be evaluated.

Association of Cardiac Galectin-3 Expression, Myocarditis, and Fibrosis in Chronic Chagas Disease Cardiomyopathy

Chronic Chagas disease cardiomyopathy, caused by Trypanosoma cruzi infection, is a major cause of heart failure in Latin America. Galectin-3 (Gal-3) has been linked to cardiac remodeling and poor prognosis in heart failure of different etiologies. Herein, we investigated the involvement of Gal-3 in the disease pathogenesis and its role as a target for disease intervention. Gal-3 expression in mouse hearts was evaluated during T. cruzi infection by confocal microscopy and flow cytometry analysis, showing a high expression in macrophages, T cells, and fibroblasts. In vitro studies using Gal-3 knockdown in cardiac fibroblasts demonstrated that Gal-3 regulates cell survival, proliferation, and type I collagen synthesis. In vivo blockade of Gal-3 with N-acetyl-d-lactosamine in T. cruzi-infected mice led to a significant reduction of cardiac fibrosis and inflammation in the heart. Moreover, a modulation in the expression of proinflammatory genes in the heart was observed. Finally, histological analysis in human heart samples obtained from subjects with Chagas disease who underwent heart transplantation showed the expression of Gal-3 in areas of inflammation, similar to the mouse model. Our results indicate that Gal-3 plays a role in the pathogenesis of experimental chronic Chagas disease, favoring inflammation and fibrogenesis. Moreover, by demonstrating Gal-3 expression in human hearts, our finding reinforces that this protein could be a novel target for drug development for Chagas cardiomyopathy.

Effects of carvedilol or amlodipine on target organ damage in L-NAME hypertensive rats: their relationship with blood pressure variability

The aim of the study was to compare the effects of chronic oral treatment with carvedilol or amlodipine on blood pressure, blood pressure variability and target organ damage in N-nitro-l-arginine methyl ester (L-NAME) hypertensive rats. Wistar rats were treated with L-NAME administered in the drinking water for 8 weeks together with oral administration of carvedilol 30 mg/kg (n = 6), amlodipine 10 mg/kg (n = 6), or vehicle (n = 6). At the end of the treatment, echocardiographic evaluation, blood pressure, and short-term variability measurements were performed. Left ventricular and thoracic aortas were removed to assess activity of metalloproteinase 2 and 9 and expression levels of transforming growth factor β, tumor necrosis factor α, and interleukin 6. Histological samples were prepared from both tissues. Carvedilol and amlodipine induced a comparable reduction of systolic and mean arterial pressure and its short-term variability in L-NAME rats. The expression of transforming growth factor β, tumor necrosis factor α, and interleukin 6 decreased in both organs after carvedilol or amlodipine treatment and the activity of metalloproteinase was reduced in aortic tissue. Treatment with carvedilol or amlodipine completely prevented left ventricular collagen deposition and morphometric alterations in aorta. Oral chronic treatment with carvedilol or amlodipine significantly attenuates blood pressure variability and reduces target organ damage and biomarkers of tissue fibrosis and inflammation in L-NAME hypertensive rats.

Myocardial and Serum Galectin-3 Expression Dynamics Marks Post-Myocardial Infarction Cardiac Remodelling

BACKGROUND

Acute myocardial infarction (MI) causes significant changes in cardiac morphology and function. Galectin-3 is a novel and potentially therapeutically important mediator of cardiac remodelling. Myocardial and serum galectin-3 expression dynamics in response to the early cardiovascular outcomes after acute MI are not fully elucidated.

METHODS

We first performed a comprehensive longitudinal microarray analyses in mice after acute MI. We then measured the serum levels of galectin-3 in a translational porcine model of coronary microembolism-induced post-ischaemic cardiac remodelling. We validated our pre-clinical studies in humans by measuring serum galectin-3 levels of 52 patients with acute ST-elevation MI (STEMI) and 11 healthy controls. We analysed galectin-3 data in relation to the development of major adverse cardiovascular outcomes (MACO).

RESULTS

Of the 9,753 genes profiled at infarcted and remote myocardium at eight different time points, dynamic myocardial overexpression of galectin-3 mRNA was detected. In a pig model of diffuse myocardial damage and cardiac remodelling, galectin-3 localised to the areas of tissue damage and myocardial fibrosis, with proportionate increase of their serum galectin-3 expression levels. In humans, increased serum galectin-3 level was associated with in-hospital MACO.

CONCLUSIONS

In this translational study, we demonstrated that galectin-3 is dynamically overexpressed in response to acute MI-induced cardiac remodelling. Elevated galectin-3 levels are associated with the development of in-hospital MACO.

Cardiac-deleterious role of galectin-3 in chronic angiotensin II-induced hypertension

Galectin-3 (Gal-3), a member of the β-galactoside lectin family, has an important role in immune regulation. In hypertensive rats and heart failure patients, Gal-3 is considered a marker for an unfavorable prognosis. Nevertheless, the role and mechanism of Gal-3 action in hypertension-induced target organ damage are unknown. We hypothesized that, in angiotensin II (ANG II)-induced hypertension, genetic deletion of Gal-3 prevents left ventricular (LV) adverse remodeling and LV dysfunction by reducing the innate immune responses and myocardial fibrosis. To induce hypertension, male C57BL/6J and Gal-3 knockout (KO) mice were infused with ANG II (3 μg·min^-1·kg^-1 sc) for 8 wk. We assessed: 1) systolic blood pressure by plethysmography, 2) LV function and remodeling by echocardiography, 3) myocardial fibrosis by histology, 4) cardiac CD68⁺ macrophage infiltration by histology, 5) ICAM-1 and VCAM-1 expression by Western blotting, 6) plasma cytokines, including interleukin-6 (IL-6), by enzyme-linked immunosorbent assay, and 7) regulatory T (T_reg) cells by flow cytometry as detected by their combined expression of CD4, CD25, and FOXP3. Systolic blood pressure and cardiac hypertrophy increased similarly in both mouse strains when infused with ANG II. However, hypertensive C57BL/6J mice suffered impaired ejection and shortening fractions. In these mice, the extent of myocardial fibrosis and macrophage infiltration was greater in histological sections, and cardiac ICAM-1, as well as plasma IL-6, expression was higher as assessed by Western blotting. However, all these parameters were blunted in Gal-3 KO mice. Hypertensive Gal-3 KO mice also had a higher number of splenic T_reg lymphocytes. In conclusion, in ANG II-induced hypertension, genetic deletion of Gal-3 prevented LV dysfunction without affecting blood pressure or LV hypertrophy. This study indicates that the ANG II effects are, in part, mediated or triggered by Gal-3 together with the related intercellular signaling (ICAM-1 and IL-6), leading to cardiac inflammation and fibrosis.

Galectin-3, Cardiac Function, and Fibrosis

This Correspondence relates to the article by Frunza et al (Myocardial Galectin-3 Expression Is Associated with Remodeling of the Pressure-Overloaded Heart and May Delay the Hypertrophic Response without Affecting Survival, Dysfunction, and Cardiac Fibrosis. Am J Pathol 2016, 186:1114-1127).

Role of Galectin-3 in Obesity and Impaired Glucose Homeostasis

Galectin-3 is an important modulator of several biological functions. It has been implicated in numerous disease conditions, particularly in the long-term complications of diabetes because of its ability to bind the advanced glycation/lipoxidation end products that accumulate in target organs and exert their toxic effects by triggering proinflammatory and prooxidant pathways. Recent evidence suggests that galectin-3 may also participate in the development of obesity and type 2 diabetes. It has been shown that galectin-3 levels are higher in obese and diabetic individuals and parallel deterioration of glucose homeostasis. Two studies in galectin-3 knockout mice fed a high-fat diet (HFD) have shown increased adiposity and adipose tissue and systemic inflammation associated with altered glucose homeostasis, suggesting that galectin-3 negatively modulates the responsiveness of innate and adaptive immunity to overnutrition. However, these studies have also shown that impaired glucose homeostasis occurs in galectin-3 knockout animals independently of obesity. Moreover, another study reported decreased weight and fat mass in HFD-fed galectin-3 knockout mice. In vitro, galectin-3 was found to stimulate differentiation of preadipocytes into mature adipocytes. Altogether, these data indicate that galectin-3 deserves further attention in order to clarify its role as a potential player and therapeutic target in obesity and type 2 diabetes.

Galectin-3 and post-myocardial infarction cardiac remodeling

This review summarizes the current literature regarding the involvement and the putative role(s) of galectin-3 in post-myocardial infarction cardiac remodeling. Post-myocardial infarction remodeling is characterized by acute loss of myocardium, which leads to structural and biomechanical changes in order to preserve cardiac function. A hallmark herein is fibrosis formation, both in the early and late phase following acute myocardial infarction. Galectin-3, a β-galactoside-binding lectin, which is a shared factor in fibrosis formation in multiple organs, has an established role in cardiac fibrosis in the setting of pressure overload, neuro-endocrine activation and hypertension, but its role in post- myocardial infarction remodeling has received less attention. However, accumulative experimental studies have shown that myocardial galectin-3 expression is upregulated after myocardial infarction, both on mRNA and protein level. This already occurs shortly after myocardial infarction in the infarcted and border zone area, and also at a later stage in the spared myocardium, contributing to tissue repair and fibrosis. This is associated with typical aspects of fibrosis formation, such as apposition of matricellular proteins and increased factors of collagen turnover. Interestingly, myocardial fibrosis in experimental post-myocardial infarction cardiac remodeling could be attenuated by galectin-3 inhibition. In clinical studies, circulating galectin-3 levels have been shown to identify patients at risk for new-onset heart failure and atrial fibrillation. Circulating galectin-3 levels also predict progressive left ventricular dilatation after myocardial infarction. From literature we conclude that galectin-3 is an active player in cardiac remodeling after myocardial infarction. Future studies should focus on the dynamics of galectin-3 activation after myocardial infarction, and study the possibilities to target galectin-3.

Prognostic value of the interaction between galectin-3 and antigen carbohydrate 125 in acute heart failure

Aims

Galectin-3 (Gal-3) and carbohydrate antigen 125 (CA125) have emerged as robust prognostic biomarkers in heart failure. Experimental data have also suggested a potential molecular interaction between CA125 and Gal-3; however, the biological and clinical relevance of this interaction is still uncertain. We sought to evaluate, in patients admitted for acute heart failure, the association between plasma Gal-3 with all-cause mortality and the risk for rehospitalizations among high and low levels of CA125.

Methods and Results

We included 264 consecutive patients admitted for acute heart failure to the Cardiology Department in a third-level center. Both biomarkers were measured on admission. Negative binomial and Cox regression models were used to evaluate the prognostic effect of the interaction between Gal-3 and CA125 (dichotomized by its median) with hospital readmission and all-cause mortality, respectively. During a median follow-up of 2 years (IQR = 1-2.8), 108 (40.9%) patients deaths and 365 rehospitalizations in 171 (69.5%) patients were registered. In a multivariable setting, the effect of Gal-3 on mortality and rehospitalization was differentially mediated by CA125 (p = 0.007 and p<0.001, respectively). Indeed, in patients with CA125 above median (>67 U/ml), values across the continuum of Gal-3 showed a positive and almost linear relationship with either the risk of death or rehospitalization. Conversely, when CA125 was below median (≤67 U/ml), Gal-3 lacked any prognostic effect on both endpoints.

Conclusion

In patients with acute heart failure, Gal-3 was strongly associated with higher risk of long-term mortality and repeated rehospitalizations, but only in those patients exhibiting higher values of CA125 (above 67 U/ml).