Galectin-3 mediates aldosterone-induced vascular fibrosis

Elevated β1-Adrenergic Receptor Autoantibody Levels Increase Atrial Fibrillation Susceptibility by Promoting Atrial Fibrosis

Objective

Beta 1-adrenergic receptor autoantibodies (β1ARAbs) have been identified as a pathogenic factor in atrial fibrillation (AF), but the underlying pathogenetic mechanism is not well understood. We assessed the hypothesis that elevated β1ARAb levels increase AF susceptibility by promoting atrial fibrosis.

Methods

A total of 70 patients with paroxysmal AF were continuously recruited. The serum levels of β1ARAb and circulating fibrosis biomarkers were analyzed by ELISA. Linear regression was used to examine the correlations of β1ARAb levels with left atrial diameter (LAD) and circulating fibrosis biomarker levels. Furthermore, we established a rabbit β1ARAb overexpression model. We conducted electrophysiological studies and multielectrode array recordings to evaluate the atrial effective refractory period (AERP), AF inducibility and electrical conduction. AF was defined as irregular, rapid atrial beats > 500 bpm for > 1000 ms. Echocardiography, hematoxylin and eosin staining, Masson's trichrome staining, and picrosirius red staining were performed to evaluate changes in atrial structure and detect fibrosis. Western blotting and PCR were used to detect alterations in the protein and mRNA expression of TGF-β1, collagen I and collagen III.

Results

Patients with a LAD ≥ 40 mm had higher β1ARAb levels than patients with a smaller LAD (8.87 ± 3.16 vs. 6.75 ± 1.34 ng/mL, P = 0.005). β1ARAb levels were positively correlated with LAD and circulating biomarker levels (all P < 0.05). Compared with the control group, the rabbits in the immune group showed the following: (1) enhanced heart rate, shortened AERP (70.00 ± 5.49 vs. 96.46 ± 3.27 ms, P < 0.001), increased AF inducibility (55% vs. 0%, P < 0.001), decreased conduction velocity and increased conduction heterogeneity; (2) enlarged LAD and elevated systolic dysfunction; (3) significant fibrosis in the left atrium identified by Masson's trichrome staining (15.17 ± 3.46 vs. 4.92 ± 1.72%, P < 0.001) and picrosirius red staining (16.76 ± 6.40 vs. 4.85 ± 0.40%, P < 0.001); and (4) increased expression levels of TGF-β1, collagen I and collagen III.

Conclusion

Our clinical and experiential studies showed that β1ARAbs participate in the development of AF and that the potential mechanism is related to the promotion of atrial fibrosis.

Serum Galectin-3 level and recurrence of atrial fibrillation post-ablation - Systematic review and meta-analysis

BACKGROUND

Serum galectin-3, a circulating biomarker of fibrosis, has been associated with atrial remodelling. Recent studies investigating serum galectin-3 and AF recurrence post-ablation have shown mixed results. We aimed to analyze the latest evidence on the association between serum galectin-3 and AF recurrence after catheter ablation.

METHODS

We performed a comprehensive search on topics that assesses serum galectin-3 and AF recurrence post-ablation up until August 2019.

RESULTS

There were 597 patients from seven studies. The mean difference of serum galectin-3 was similar in both AF recurrence and non AF recurrence group (mean difference 0.78 ng/mL [-0.56, 2.13]; p = 0.25; I2: 69%. Upon removal of a study in sensitivity analysis, the serum galectin-3 became higher in AF recurrence group (mean difference 1.41 ng/mL [0.47, 2.34], p = 0.003; I2: 17%). Serum galectin-3 was associated with a higher risk for AF recurrence (HR 1.25 [1.01, 1.55]; p = 0.04; I2: 76%). Upon removal of a study in sensitivity analysis, HR became 1.45 [1.07, 1.96], p = 0.02; I2: 47%. Meta-analysis of adjusted HR demonstrated that high serum galectin-3 independently predicts AF recurrence (HR 1.15 [1.02, 1.29], p < 0.02; I2: 57%, p = 0.10) CONCLUSION: Serum galectin-3 is associated with an increased risk of AF recurrence post-ablation. Further studies are required, especially emphasis on the cut-off point should be given, before integrating it in routine risk stratification for AF ablation.

High-sensitivity Troponin I Predicts Galectin-3 in Chronic Kidney Disease Patients

PURPOSE

Plasma galectin-3 (pG3) regulates inflammation. B-type natriuretic peptide (BNP), high-sensitivity Troponin I (hsTnI), and pG3 concentrations are elevated in chronic kidney disease (CKD) patients. The associations of pG3 with hsTnI/BNP are unclear. We explored the relationship of hsTnI and BNP with pG3 in Asian CKD patients and healthy controls.

METHODS

We retrieved prospectively collected frozen plasma samples from 163 stable CKD patients and 105 healthy controls. BNP, hsTnI and pG3 were assayed. pG3 was assessed for associations with age, gender, ethnicity, blood pressures; height, weight, body mass index (BMI), previously diagnosed CKD, diabetes, hypertension, coronary artery disease, estimated glomerular filtration rate (eGFR); C-reactive protein, beta-trace protein, 24 h urine protein, serum albumin, uric acid and cystatin C. We created two models predicting pG3 using multiple linear regression. Akaike Information Criterion (AIC) was used for comparison. Significance was taken at P < 0.05.

RESULTS

CKD versus healthy participants: mean BMI (28.2 vs. 24.9 kg/m²), median serum creatinine (159 vs. 69 µmol/L; 1.8 vs. 0.78 mg/dL), median eGFR (49 vs. 104 mL/min/1.73m²), median pG3 (29.4 vs. 15.4 ng/mL), median BNP (136 vs. 23 pg/mL), and median hsTnI (12.5 vs. 2.6 pg/mL). By univariate analysis, all variables are associated with pG3 except weight, gender and diagnosis of cerebrovascular or peripheral vascular diseases. A parsimonious model selected for hsTnI, BMI, serum albumin, cystatin C and eGFR (AIC = 77.6).

CONCLUSION

BNP and hsTnI are associated with pG3 in Asian CKD patients. hsTnI is a better predictor of pG3.

Vascular and inflammatory mineralocorticoid receptors in kidney disease

Mineralocorticoid receptor (MR) activation in the kidney can occur outside the aldosterone-sensitive distal nephron in sites including the endothelium, smooth muscle and inflammatory cells. MR activation in these cells has deleterious effects on kidney structure and function by promoting oxidative injury, endothelial dysfunction and stiffness, vascular remodelling and calcification, decreased relaxation and activation of T cells and pro-inflammatory macrophages. Here, we review the data showing the cellular consequences of MR activation in endothelial, smooth muscle and inflammatory cells and how this affects the kidney in pathological situations. The evidence demonstrating a benefit of pharmacological or genetic MR inhibition in various models of kidney disease is also discussed.

Plasma levels of the cardiovascular protective endogenous nucleoside adenosine are reduced in patients with primary aldosteronism without affecting ischaemia-reperfusion injury: A prospective case-control study

BACKGROUND

Patients with primary aldosteronism (PA) experience more cardiovascular events compared to patients with essential hypertension (EHT), independent from blood pressure levels. In animals, mineralocorticoid receptor antagonists limit ischaemia-reperfusion (IR) injury by increasing extracellular adenosine formation and adenosine receptor stimulation. Adenosine is an endogenous compound with profound cardiovascular protective effects. Firstly, we hypothesized that patients with PA have lower circulating adenosine levels which might contribute to the observed increased cardiovascular risk. Secondly, we hypothesized that by this mechanism, patients with PA are more susceptible to IR compared to patients with EHT.

DESIGN

In our prospective study in 20 patients with PA and 20 patients with EHT, circulating adenosine was measured using a pharmacological blocker solution that halts adenosine metabolism after blood drawing. Brachial artery flow-mediated dilation (FMD) before and after forearm IR was used as a well-established method to study IR injury.

RESULTS

Patients with PA had a 33% lower adenosine level compared to patients with EHT (15.3 [13.3-20.4] vs 22.7 [19.4-36.8] nmol/L, respectively, P < .01). The reduction in FMD after IR, however, did not differ between patients with PA and patients with EHT (-1.0 ± 2.9% vs -1.6 ± 1.6%, respectively, P = .52).

CONCLUSIONS

As adenosine receptor stimulation induces various powerful protective cardiovascular effects, its lower concentration in patients with PA might be an important novel mechanism that contributes to their increased cardiovascular risk. We suggest that modulation of the adenosine metabolism is an exciting novel pharmacological opportunity to limit cardiovascular risk in patients with PA that needs further exploration.

CLINICAL CHARACTERISTICS OF MEN AND WOMEN IN YOUNG AND MIDDLE AGE WITH ARTERIAL HYPERTENSION AT DIFFERENT GALECTIN-3 PLASMA LEVELS ACCORDING TO THE RESULT OF LINEAR REGRESSION ANALYSIS

The aim of the research was to describe the clinical charachters of male and female patients with stage II arterial hypertension (AH) of young and middle age with different gradations of galectin-3 plasma levels according to multiple linear stepwise regression analysis. Materials and methods: 160 patients with AH of different sex (male and female) and age (young (18–44 years), middle (45–60 years)) were examined (clinical, laboratory and instrumental). Multiple linear regression was used to determine the clinical presentation of patients with AH at different levels of the neurohormone (StatSoft's Statistica MultipleRegression v. 10.0 module). which were divided into groups that vi told for the entirely different patient characteristics. multiple linear regression was performed for each indicator separately and the results have been shaped in the form of regression equations. Results. Patients with young and middle-aged AH have been found to be relatively high (RH) levels of galectin-3 associated with: the presence of a complex of metabolic risk factors – obesity and dyslipidemia; in combination with multiple features of structural and functional changes in the cardiovascular system, such as the presence of concentric left ventricular (LV) hypertrophy in combination with myocardial relaxation disorders (Е/e' aver>7.2) and signs of hemodynamic overload of the left atrium (LA) (LA volume index (LAVi)>34 ml/m2); the presence of valve dysfunctions in the form of mitral (1–2 degree) and aortic regurgitation (1 stage); the presence of structural remodeling of the carotid arteries (intima-media thickness (IMT)>0.91 mm). Plasma abdominal obesity was the most informative marker of RH galectin-3 in plasma, IMT>0.91 mm and LAVi>34 ml/m2. Conclusions. The association of plasma galectin-3 levels with various clinical and instrumental indicators indicates a certain effect of the neurohormone on the course of AH in young and middle-aged male and female patients. Of indisputable interest is the determination of the features of the course of AH and the clinical profile of patients at different gradations (relatively low (RL), relatively moderate (RM) and relatively high (RH)) galectin-3 plasma level.

Cardiac Chagas Disease: MMPs, TIMPs, Galectins, and TGF-β as Tissue Remodelling Players

A century after the discovery of Chagas disease, studies are still needed to establish the complex pathophysiology of this disease. However, it is known that several proteins and molecules are related to the establishment of this disease, its evolution, and the appearance of its different clinical forms. Metalloproteinases and their tissue inhibitors, galectins, and TGF-β are involved in the process of infection and consequently the development of myocarditis, tissue remodeling, and fibrosis upon infection with Trypanosoma cruzi. Thus, considering that the heart is one of the main target organs in Chagas disease, knowledge regarding the mechanisms of action of these molecules is essential to understand how they interact and trigger local and systemic reactions and, consequently, determine whether they contribute to the development of Chagas' heart disease. In this sense, it is believed that the inflammatory microenvironment caused by the infection alters the expression of these proteins favoring progression of the host-parasite cycle and thereby stimulating cardiac tissue remodeling mechanisms and fibrosis. The aim of this review was to gather information on metalloproteinases and their tissue inhibitors, galectins, and TGF-β and discuss how these molecules and their different interrelationships contribute to the development of Chagas' heart disease.

CT-1 (Cardiotrophin-1)-Gal-3 (Galectin-3) Axis in Cardiac Fibrosis and Inflammation

Myocardial fibrosis is a main contributor to the development of heart failure (HF). CT-1 (cardiotrophin-1) and Gal-3 (galectin-3) are increased in HF and associated with myocardial fibrosis. The aim of this study is to analyze whether CT-1 regulates Gal-3. Proteomic analysis revealed that Gal-3 was upregulated by CT-1 in human cardiac fibroblasts in parallel with other profibrotic and proinflammatory markers. CT-1 upregulation of Gal-3 was mediated by ERK (extracellular signal-regulated kinase) 1/2 and Stat-3 (signal transducer and activator of transcription 3) pathways. Male Wistar rats and B6CBAF1 mice treated with CT-1 (20 µg/kg per day) presented higher cardiac Gal-3 levels and myocardial fibrosis. In CT-1-treated rats, direct correlations were found between cardiac CT-1 and Gal-3 levels, as well as between Gal-3 and perivascular fibrosis. Gal-3 genetic disruption in human cardiac fibroblasts and pharmacological Gal-3 inhibition in mice prevented the profibrotic and proinflammatory effects of CT-1. Dahl salt-sensitive hypertensive rats with diastolic dysfunction showed increased cardiac CT-1 and Gal-3 expression together with cardiac fibrosis and inflammation. CT-1 and Gal-3 directly correlated with myocardial fibrosis. In HF patients, myocardial and plasma CT-1 and Gal-3 were increased and directly correlated. In addition, HF patients with high CT-1 and Gal-3 plasma levels presented an increased risk of cardiovascular death. Our data suggest that CT-1 upregulates Gal-3 which, in turn, mediates the proinflammatory and profibrotic myocardial effects of CT-1. The elevation of both molecules in HF patients identifies a subgroup of patients with a higher risk of cardiovascular mortality. The CT-1/Gal-3 axis emerges as a candidate therapeutic target and a potential prognostic biomarker in HF.

Galectin-3: A Harbinger of Reactive Oxygen Species, Fibrosis, and Inflammation in Pulmonary Arterial Hypertension

Significance: Pulmonary arterial hypertension (PAH) is a progressive disease arising from the narrowing of pulmonary arteries (PAs) resulting in high pulmonary arterial blood pressure and ultimately right ventricle (RV) failure. A defining characteristic of PAH is the excessive and unrelenting inward remodeling of PAs that includes increased proliferation, inflammation, and fibrosis. Critical Issues: There is no cure for PAH nor interventions that effectively arrest or reverse PA remodeling, and intensive research over the past several decades has sought to identify novel molecular mechanisms of therapeutic value. Recent Advances: Galectin-3 (Gal-3) is a carbohydrate-binding lectin remarkable for its chimeric structure, composed of an N-terminal oligomerization domain and a C-terminal carbohydrate-recognition domain. Gal-3 has been identified as a regulator of numerous changes in cell behavior that contributes to aberrant PA remodeling, including cell proliferation, inflammation, and fibrosis, but its role in PAH has remained poorly understood until recently. In contrast, pathological roles for Gal-3 have been proposed in cancer and inflammatory and fibroproliferative disorders, such as pulmonary vascular and cardiac fibrosis. Herein, we summarize the recent literature on the role of Gal-3 in the development of PAH. We provide experimental evidence supporting the ability of Gal-3 to influence reactive oxygen species production, NADPH oxidase enzyme expression, and redox signaling, which have been shown to contribute to both vascular remodeling and increased pulmonary arterial pressure. Future Directions: While several preclinical studies suggest that Gal-3 promotes hypertensive pulmonary vascular remodeling, the clinical significance of Gal-3 in human PAH remains to be established. Antioxid. Redox Signal. 00, 000-000.

Pleiotropic Effects of Modified Citrus Pectin

Modified citrus pectin (MCP) has a low-molecular-weight degree of esterification to allow absorption from the small intestinal epithelium into the circulation. MCP produces pleiotropic effects, including but not limited to its antagonism of galectin-3, which have shown benefit in preclinical and clinical models. Regarding cancer, MCP modulates several rate-limiting steps of the metastatic cascade. MCP can also affect cancer cell resistance to chemotherapy. Regarding fibrotic diseases, MCP modulates many of the steps involved in the pathogenesis of aortic stenosis. MCP also reduces fibrosis to the kidney, liver, and adipose tissue. Other benefits of MCP include detoxification and improved immune function. This review summarizes the pleiotropic effects of MCP.

Cardiac Biomarkers and Risk of Incident Heart Failure in Chronic Kidney Disease: The CRIC (Chronic Renal Insufficiency Cohort) Study

Background

Cardiac biomarkers may signal mechanistic pathways involved in heart failure (HF), a leading complication in chronic kidney disease. We tested the associations of NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), high‐sensitivity troponin T (hsTnT), galectin‐3, growth differentiation factor‐15 (GDF‐15), and soluble ST2 (sST2) with incident HF in chronic kidney disease.

Methods and Results

We examined adults with chronic kidney disease enrolled in a prospective, multicenter study. All biomarkers were measured at baseline. The primary outcome was incident HF. Secondary outcomes included HF with preserved ejection fraction (EF≥50%) and reduced ejection fraction (EF<50%). Cox models were used to test the association of each cardiac biomarker with HF, adjusting for demographics, kidney function, cardiovascular risk factors, and medication use. Among 3314 participants, all biomarkers, with the exception of galectin‐3, were significantly associated with increased risk of incident HF (hazard ratio per SD higher concentration of log‐transformed biomarker): NT‐proBNP (hazard ratio, 2.07; 95% CI, 1.79–2.39); hsTnT (hazard ratio, 1.38; 95% CI, 1.21–1.56); GDF‐15 (hazard ratio, 1.44; 95% CI, 1.26–1.66) and sST2 (hazard ratio, 1.19; 95% CI, 1.05–1.35). Higher NT‐proBNP, hsTnT, and GDF‐15 were also associated with a greater risk of HF with reduced EF; while higher NT‐proBNP GDF‐15 and sST2 were associated with HF with preserved EF. Galectin‐3 was not associated with either HF with reduced EF or HF with preserved EF.

Conclusions

In chronic kidney disease, elevations of NT‐proBNP, hsTnT, GDF‐15, sST2 were associated with incident HF. There was a borderline association of galectin‐3 with incident HF. NT‐proBNP and hsTnT were more strongly associated with HF with reduced EF, while the associations of the newer biomarkers GDF‐15 and sST2 were stronger for HF with preserved EF.

Investigation of galectin-3 levels in diabetic foot ulcers

OBJECTIVE

It has been shown that galectin-3 (Gal-3) promotes angiogenesis and new vessel formation. Serum Gal-3 is a risk factor for vascular complications in type 2 diabetes. The aim of this study is to compare Gal-3 levels with a range of biochemical parameters.

METHOD

A prospective study consisted of individuals as a control group (group 1), patients diagnosed with type 2 diabetes without DFUs (group 2), and patients with type 2 diabetes with a DFU (group 3). Patient levels of endothelin-1 (ET-1), vascular endothelial growth factor-A (VEGF-A), nitric oxide (NO), and Gal-3 were measured.

RESULTS

In total, 91 patients participated, (28 male, 63 female with a mean age of 55.83±6.35 years) Mean ET-1 (39.0±16.9), NO (17.6±7.6), VEGF-A (33.5±13.4) and Gal-3 (535.1±420.5) levels were significantly higher in group 3 compared with the other two groups (p<0.01). Furthermore, the Gal-3 level was positively and statistically significantly correlated with C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), ET-1 and NO levels in all groups.

CONCLUSION

In our study, the level of Gal-3 was shown to be positively correlated with the VEGF-A level. Hence, Gal-3 can be considered as a defence mechanism against complications of diabetes, thus contributing to wound healing. Gal-3 may play a critical role in DFU formation and progression. Moreover, it could be suggested that Gal-3 may give an indication of prognosis, as it elevates VEGF-A levels and stimulates angiogenesis. Further studies are required to confirm the findings of this study.

Endoglin Protein Interactome Profiling Identifies TRIM21 and Galectin-3 as New Binding Partners

Endoglin is a 180-kDa glycoprotein receptor primarily expressed by the vascular endothelium and involved in cardiovascular disease and cancer. Heterozygous mutations in the endoglin gene (ENG) cause hereditary hemorrhagic telangiectasia type 1, a vascular disease that presents with nasal and gastrointestinal bleeding, skin and mucosa telangiectases, and arteriovenous malformations in internal organs. A circulating form of endoglin (alias soluble endoglin, sEng), proteolytically released from the membrane-bound protein, has been observed in several inflammation-related pathological conditions and appears to contribute to endothelial dysfunction and cancer development through unknown mechanisms. Membrane-bound endoglin is an auxiliary component of the TGF-β receptor complex and the extracellular region of endoglin has been shown to interact with types I and II TGF-β receptors, as well as with BMP9 and BMP10 ligands, both members of the TGF-β family. To search for novel protein interactors, we screened a microarray containing over 9000 unique human proteins using recombinant sEng as bait. We find that sEng binds with high affinity, at least, to 22 new proteins. Among these, we validated the interaction of endoglin with galectin-3, a secreted member of the lectin family with capacity to bind membrane glycoproteins, and with tripartite motif-containing protein 21 (TRIM21), an E3 ubiquitin-protein ligase. Using human endothelial cells and Chinese hamster ovary cells, we showed that endoglin co-immunoprecipitates and co-localizes with galectin-3 or TRIM21. These results open new research avenues on endoglin function and regulation.

Vascular mineralocorticoid receptor activation and disease

Mineralocorticoid receptor activation in endothelial and smooth muscle cells can promote vascular disease by increasing oxidative stress, promoting inflammation, accelerating vascular stiffness, remodeling, and calcification, altering vessel responsiveness to various vasoactive factors, thus altering vascular tone and blood pressure, and by altering angiogenesis. Here, we review the recent evidence highlighting the impact of vascular mineralocorticoid receptor activation in pathological situations, including kidney injury, vascular injury associated with metabolic diseases, atherosclerosis, cerebral vascular injury during hypertension, vascular stiffening and aging, pulmonary hypertension, vascular calcification, cardiac remodeling, wound healing, inflammation, thrombosis, and disorders related to angiogenic defects in the eye. The possible mechanisms implicating mineralocorticoid receptor activation in various vascular disorders are discussed. Altogether, recent evidence points towards pharmacological mineralocorticoid receptor inhibition as a strategy to treat diseases in which overactivation of the mineralocorticoid receptor in endothelial and/or smooth muscle cells may play a pivotal role.

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.

Arterial Remodeling and Dysfunction in the ZSF1 Rat Model of Heart Failure With Preserved Ejection Fraction

BACKGROUND

The interplay between the stiffened heart and vessels has long been viewed as a core mechanism in heart failure with preserved ejection fraction, but the incremental vascular molecular remodeling mechanisms from systemic arterial hypertension to heart failure with preserved ejection fraction remain poorly investigated. Our aim was to characterize central arterial remodeling and dysfunction in ZSF1 obese rats and to compare it with hypertensive ZSF1 lean and healthy Wistar-Kyoto controls.

METHODS AND RESULTS

Twenty-week-old male ZSF1 obese (n=9), lean (n=9), and Wistar-Kyoto rats (n=9) underwent left ventricular pressure-volume loop evaluation and synchronous acquisition of ascending aortic flow and pressure. Aortic rings underwent functional evaluation, histology, and molecular biology studies. Although mean arterial pressure, characteristic aortic impedance, and reactivity to phenylephrine were similarly increased in hypertensive ZSF1 lean and obese, only ZSF1 obese showed impaired relaxation and upward-shifted end-diastolic pressure-volume relationships despite preserved systolic function indexes, denoting heart failure with preserved ejection fraction. ZSF1 obese phenotype further showed decreased aortic compliance, increased wave reflection, and impaired direct NO donor and endothelial-mediated vasodilation which were accompanied on structural and molecular grounds by aortic media thickening, higher collagen content and collagen/elastin ratio, increased fibronectin and α-5 integrin protein expression and upregulated TGF (transforming growth factor)-β and CTGF (connective tissue growth factor) levels.

CONCLUSIONS

Functional, molecular, and structural disturbances of central vessels and their potentially underlying pathways were newly characterized in experimental heart failure with preserved ejection fraction rendering the ZSF1 obese rat model suitable for preclinical testing.

Mechanisms of cardiac collagen deposition in experimental models and human disease

The inappropriate deposition of extracellular matrix within the heart (termed cardiac fibrosis) is associated with nearly all types of heart disease, including ischemic, hypertensive, diabetic, and valvular. This alteration in the composition of the myocardium can physically limit cardiomyocyte contractility and relaxation, impede electrical conductivity, and hamper regional nutrient diffusion. Fibrosis can be grossly divided into 2 types, namely reparative (where collagen deposition replaces damaged myocardium) and reactive (where typically diffuse collagen deposition occurs without myocardial damage). Despite the widespread association of fibrosis with heart disease and general understanding of its negative impact on heart physiology, it is still not clear when collagen deposition becomes pathologic and translates into disease symptoms. In this review, we have summarized the current knowledge of cardiac fibrosis in human patients and experimental animal models, discussing the mechanisms that have been deduced from the latter in relation to the former. Because assessment of the extent of fibrosis is paramount both as a research tool to further understanding and as a clinical tool to assess patients, we have also summarized the current state of noninvasive/minimally invasive detection systems for cardiac fibrosis. Albeit not exhaustive, our aim is to provide an overview of the current understanding of cardiac fibrosis, both clinically and experimentally.

Evaluation of serum galectin-3 concentrations in patients with hypothyroidism

Aims: Hypothyroidism is the most commonly encountered hormone deficiency determined in all age groups. Serum galectin-3 concentrations that play important roles in cellular proliferation and adhesion were not studied before in hypothyroidism. In this study, we aimed to determine the relationship between serum galectin-3 concentrations and hypothyroidism. Methods: A total of 83 individuals, 46 patients with hypothyroidism and 37 healthy controls, were included in the study. Among 46 patients with hypothyroidism, anti-TPO concentrations were higher than the reference range in 22 of them while it was in reference range in remaining 24 patients. Routine laboratory data (glucose, urea, creatinine, AST, ALT, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride, TSH, fT4, fT3, anti-TPO, anti-Tg) and galectin-3 concentrations were compared between the groups. Galectin-3 concentrations were measured by Enzyme linked immunosorbent assay. Results: Galectin-3 concentrations were significantly higher in patients with hypothyroidism compared to the control group (2.89 (1.17-10.79); 1.95 (1.15-6.11) ng/mL, p = .001, respectively). There was a positive correlation between galectin-3 concentrations and TSH, anti-Tg and triglyceride concentrations; while a negative correlation was present between fT4 and fT3 and galectin-3 concentrations (p < .05). Conclusions: For the first time in the literature, we determined elevated serum galectin-3 concentrations in patients with hypothyroidism compared with healthy controls. We believe that increased galectin-3 concentrations may play a role in hyperplasia of thyroid gland that is important in pathogenesis of hypothyroidism and high concentrations of galectin-3 may be associated with hypertriglyceridemia seen in hypothyroidism.

Galectin-3 aggravates pulmonary arterial hypertension via immunomodulation in congenital heart disease

Pulmonary arterial hypertension (PAH) is reported to contribute to right ventricular failure and death. PAH of variable degrees is often related to congenital heart disease (CHD). Galectin-3 (Gal-3) has been proven to be of great importance in PAH and CHD. Therefore, we investigated the specific mechanism of Gal-3 in CHD-PAH. Patients with CHD-PAH were enrolled to detect the changes of T-cell subsets, cytokine levels, and other related inflammatory cells in the plasma and to assess the Gal-3 levels in the serum. Next, CHD-PAH mouse models were established and treated with restored or depleted Gal-3 to evaluate the systolic pulmonary artery pressure (sPAP) and right ventricular hypertrophy index (RVHI), to determine levels of IL-4, IL-5, IL-13, AKT and p-AKT along with proliferation of pulmonary artery smooth muscle cells (PASMCs). Finally, we explored the effects of adoptive transfer of CD4⁺T cells on CHD-PAH in mice with Gal-3 knockdown to further investigate the role of Gal-3 in vivo. Initially, Gal-3 was up-regulated in patients with CHD-PAH. Subsequently, it was demonstrated that restored Gal-3 increased sPAP and RVHI, and promoted proliferation of PASMCs by activating the immune response with elevated levels of IL-4, IL-5, IL-13 and p-AKT. Finally, adoptive transfer of CD4⁺T cells promoted CD4⁺T cell perivascular infiltration and the progression of CHD-PAH in mice with Gal-3 knockdown. Collectively, the current study suggests a facilitating role of Gal-3 in pulmonary artery remodeling and progression of CHD-PAH via activation of Th2.

Galectins in the Pathogenesis of Cerebrovascular Accidents: An Overview

Due to limitations of neuroimaging, such as the isodense appearance of blood to neuronal tissue in subacute hemorrhagic stroke, a body of studies have been performed to evaluate candidate biomarkers which may aid in accurate determination of cerebrovascular accident type. Beyond aiding in the delineation of stroke cause, biomarkers could also confer useful prognostic information to help clinicians plan use of resources. One of the candidate biomarkers studied for detection of cerebrovascular accident (CVA) includes a class of proteins called galectins. Galectins bind β-galactoside through a highly conserved carbohydrate recognition domain, endowing an ability to interact with carbohydrate moieties on glycoproteins, some of which are relevant to CVA response. Furthermore, galectins-1, -2, -3, -9, and -12 are expressed in tissues relevant to CVA, and some exhibit characteristics (eg, extracellular secretion) that could render feasible their detection in serum. Galectins-1 and -3 appear to have the largest amounts of preclinical evidence, consistently demonstrating increased activity and expression levels during CVA. However, a lack of standardization of biochemical assays across cohort studies limits further translation of these basic science studies. This review aims to increase awareness of the biochemical roles of galectins in CVA, while also highlighting challenges and remaining questions preventing the translation of basic science observations into a clinically useful test.

Prognostic impact of galectin-3 in chronic kidney disease patients: a systematic review and meta-analysis

BACKGROUND

Galectin-3 as a β-galactoside-binding lectin, which has served important functions in numerous biological activities including cell growth, apoptosis, pre-mRNA splicing, differentiation, transformation, angiogenesis, inflammation, fibrosis, and host defense, may be used in prediction of clinical outcomes in CKD patients. However, the given results remain debatable and inconclusive. Hence, we performed a comprehensive meta-analysis to clarify the predictive value of galectin-3 in patients with CKD, especially ESRD patients going on dialysis.

METHODS

PubMed and Embase electronic databases were searched to identify eligible studies reporting the association between galectin-3 and adverse outcomes in CKD patients. We searched the literatures published October 2018 or earlier. We used both fix-effects and random-effects models to calculate the overall effect estimate. An I² > 50% indicates at least moderate statistical heterogeneity. A sensitivity analysis and subgroup analysis were performed to find the origin of heterogeneity.

RESULTS

We ultimately enrolled five studies with a total of 5226 patients in this meta-analysis. The result showed that high galectin-3 levels were associated with increased risk of all-cause mortality and cardiovascular (CV) events in CKD patients. For every 1% increased in galectin-3, the risk of all-cause mortality increased by 37.9% (HR 1.379, 95% CI 1.090-1.744). Much more, the risk of CV events in CKD patients was also significantly increased (HR 1.054, 95% CI 1.007-1.102) with no statistical heterogeneity among the studies (I² = 0.0%, p = 0.623). However, there was no statistical difference between the risk of all-cause mortality and galectin-3 in HD patients (HR 1.171, 95% CI 0.963-1.425).

CONCLUSIONS

Our meta-analysis suggests that high levels of galectin-3 may increase the risk of all-cause mortality and CV events in CKD patients, however, probably not a sensitive biomarker for outcomes in HD patients. Further studies were warranted to validate our findings.

Mineralocorticoid receptor antagonists and kidney diseases: pathophysiological basis

Chronic kidney disease (CKD) represents a global health concern, and its prevalence is increasing. The ultimate therapeutic option for CKD is kidney transplantation. However, the use of drugs that target specific pathways to delay or halt CKD progression, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and sodium-glucose co-transporter-2 (SGLT-2) inhibitors is limited in clinical practice. Mineralocorticoid receptor activation in nonclassical tissues, such as the endothelium, smooth muscle cells, inflammatory cells, podocytes, and fibroblasts may have deleterious effects on kidney structure and function. Several preclinical studies have shown that mineralocorticoid receptor antagonists (MRAs) ameliorate or cure kidney injury and dysfunction in different models of kidney disease. In this review, we present the preclinical evidence showing a benefit of MRAs in acute kidney injury, the transition from acute kidney injury to CKD, hypertensive and diabetic nephropathy, glomerulonephritis, and kidney toxicity induced by calcineurin inhibitors. We also discuss the molecular mechanisms responsible for renoprotection related to MRAs that lead to reduced oxidative stress, inflammation, fibrosis, and hemodynamic alterations. The available clinical data support a benefit of MRA in reducing proteinuria in diabetic kidney disease and improving cardiovascular outcomes in CKD patients. Moreover, a benefit of MRAs in kidney transplantation has also been observed. The past and present clinical trials describing the effect of MRAs on kidney injury are presented, and the risk of hyperkalemia and use of other options, such as potassium binding agents or nonsteroidal MRAs, are also addressed. Altogether, the available preclinical and clinical data support a benefit of using MRAs in CKD, an approach that should be further explored in future clinical trials.

Galectin-3 is expressed in vascular smooth muscle cells and promotes pulmonary hypertension through changes in proliferation, apoptosis, and fibrosis

A defining characteristic of pulmonary hypertension (PH) is the extensive remodeling of pulmonary arteries (PAs), which results in progressive increases in vascular resistance and stiffness and eventual failure of the right ventricle. There is no cure for PH and identification of novel molecular mechanisms that underlie increased proliferation, reduced apoptosis, and excessive extracellular matrix production in pulmonary artery smooth muscle cells (PASMCs) is a vital objective. Galectin-3 (Gal-3) is a chimeric lectin and potent driver of many aspects of fibrosis, but its role in regulating PASMC behavior in PH remains poorly understood. Herein, we evaluated the importance of increased Gal-3 expression and signaling on PA vascular remodeling and cardiopulmonary function in experimental models of PH. Gal-3 expression was quantified by qRT-PCR, immunoblotting, and immunofluorescence imaging, and its functional role was assessed by specific Gal-3 inhibitors and CRISPR/Cas9-mediated knockout of Gal-3 in the rat. In rat models of PH, we observed increased Gal-3 expression in PASMCs, which stimulated migration and resistance to apoptosis, whereas silencing or genetic deletion reduced cellular migration and PA fibrosis and increased apoptosis. Gal-3 inhibitors attenuated and reversed PA remodeling and fibrosis, as well as hemodynamic indices in monocrotaline (MCT)-treated rats in vivo. These results were supported by genetic deletion of Gal-3 in both MCT and Sugen Hypoxia rat models. In conclusion, our results suggest that elevated Gal-3 levels contribute to inappropriate PA remodeling in PH by enhancing multiple profibrotic mechanisms. Therapeutic strategies targeting Gal-3 may be of benefit in the treatment of PH.

Sleep apnea and galectin-3: possible sex-specific relationship

PURPOSE

Sleep apnea is associated with increased risk of cardiovascular disease. Elevated plasma galectin-3 levels, a biomarker associated with myocardial fibrosis, are also associated with adverse cardiovascular events, including heart failure. Our objective was to determine the relationship between severity of sleep apnea and plasma levels of galectin-3 and to determine whether this relationship was modified by sex.

METHODS

We performed a cross-sectional study of 471 Mexican Americans from Starr County, TX who underwent an overnight, in-home sleep evaluation, and plasma measurement of galectin-3. Severity of sleep apnea was based on apnea hypopnea index (AHI). Multivariable linear regression modeling was used to determine the association between categories of sleep apnea and galectin-3. We also tested for interactions by sex.

RESULTS

The mean age was 53 years, and 74% of the cohort was female. The prevalence of moderate to severe sleep apnea (AHI > 15 apnea-hypopnea events per hour) was 36.7%. Moderate to severe sleep apnea was associated with increased levels of galectin-3 in the entire population, but we identified a statistically significant interaction between galectin-3 levels and category of sleep apnea by sex (p for interaction = 0.02). Plasma galectin levels were significantly higher in women with moderate or severe sleep apnea than women with no/mild sleep apnea (multivariable adjusted p < 0.001), but not in men (p = 0.5).

CONCLUSIONS

Sleep apnea is associated elevated galectin-3 levels in women but not men. Our findings highlight a possible sex-specific relationship between sleep apnea and galectin-3, a biomarker of potential myocardial fibrosis that has been associated with increased cardiovascular risk.

Towards better definition, quantification and treatment of fibrosis in heart failure. A scientific roadmap by the Committee of Translational Research of the Heart Failure Association (HFA) of the European Society of Cardiology

Fibrosis is a pivotal player in heart failure development and progression. Measurements of (markers of) fibrosis in tissue and blood may help to diagnose and risk stratify patients with heart failure, and its treatment may be effective in preventing heart failure and its progression. A lack of pathophysiological insights and uniform definitions has hampered the research in fibrosis and heart failure. The Translational Research Committee of the Heart Failure Association discussed several aspects of fibrosis in their workshop. Early insidious perturbations such as subclinical hypertension or inflammation may trigger first fibrotic events, while more dramatic triggers such as myocardial infarction

and myocarditis give rise to full blown scar formation and ongoing fibrosis in diseased hearts. Aging itself is also associated with a cardiac phenotype that includes fibrosis. Fibrosis is an extremely heterogeneous phenomenon, as several stages of the fibrotic process exist, each with different fibrosis subtypes and a different composition of various cells and proteins — resulting in a very complex pathophysiology. As a result, detection of fibrosis, e.g. using current cardiac imaging modalities or plasma biomarkers, will detect only specific subforms of fibrosis, but cannot capture all aspects of the complex fibrotic process. Furthermore, several anti‐fibrotic therapies are under investigation, but such therapies generally target aspecific aspects of the fibrotic process and suffer from a lack of precision. This review discusses the mechanisms and the caveats and proposes a roadmap for future research.

Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology

The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT₁R) is believed to mediate most functions of ANG II in the system. AT₁R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT₁R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT₁R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.

The association among biomarkers of renal and heart function in patients with heart failure: the role of NGAL

AIM

The NGAL is a biomarker of renal injury associated with the progression of heart failure (HF). We examine the association of NGAL with galectin-3 in patients with chronic HF.

METHODS

We consecutively enrolled 115 subjects with stable ischemic HF of reduced ejection fraction. Serum levels of galectin-3, b-type natriuretic peptide and NGAL were measured.

RESULTS

NGAL levels were positively correlated with galectin-3 (rho = 0.26; p = 0.04) and b-type natriuretic peptide levels (rho = 0.30; p = 0.005) and inversely correlated with ejection fraction (rho = -0.31; p = 0.02) and creatinine clearance levels. The NGAL was independently associated with galectin-3 levels.

CONCLUSION

A positive correlation between NGAL and galectin-3 in HF patients was found, revealing a potential association between renal injury and myocardial fibrosis and remodeling in HF.

A role for fumarate hydratase in mediating oxidative effects of galectin-3 in human cardiac fibroblasts

AIMS

Galectin-3 (Gal-3), a β-galactoside-binding lectin involved in cardiac inflammation and fibrosis, could regulate oxidative stress, although the mechanisms have not been elucidated. We herein investigated the changes in oxidative stress-related mediators induced by Gal-3 in human cardiac fibroblasts and in pathological animal and human models of cardiac diseases.

RESULTS

Using quantitative proteomics and immunodetection approaches, we have identified that Gal-3 down-regulated fumarate hydratase (FH) in human cardiac fibroblasts. In parallel, Gal-3 increased fumarate production in a time-dependent manner. Gal-3 treatment enhanced carbonylated proteins detected through OxyBlot technique. Interestingly, treatment of cells with fumarate induced oxidative stress, enhanced fibroblast activation markers and increased collagen and interleukin-6 secretion. In Gal-3-silenced cells and in heart from Gal-3 knock-out mice, FH was increased and fumarate was decreased. In myocardial biopsies from patients with aortic stenosis (AS, n=26), FH levels were decreased as compared to Controls (n=13). Cardiac Gal-3 inversely correlated with FH levels in myocardial biopsies. In an experimental model of AS rats, pharmacological inhibition of Gal-3 restored cardiac FH, decreased fumarate concentration and improved oxidative status.

CONCLUSION

In human cardiac fibroblasts, Gal-3 decreased FH expression increasing fumarate concentration and promoting oxidative stress. In human AS, cardiac levels of Gal-3 inversely associated with FH. Gal-3 blockade restored FH and improved fumarate and oxidative stress status in AS rats. FH is therefore a key molecule mediating Gal-3-induced oxidative stress in cardiac cells.

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.

Mineralocorticoid Receptor and Aldosterone-Related Biomarkers of End-Organ Damage in Cardiometabolic Disease

The mineralocorticoid receptor (MR) was first identified as a blood pressure regulator, modulating renal sodium handling in response to its principal ligand aldosterone. The mineralocorticoid receptor is also expressed in many tissues other than the kidney, such as adipose tissue, heart and vasculature. Recent studies have shown that MR plays a relevant role in the control of cardiovascular and metabolic function, as well as in adipogenesis. Dysregulation of aldosterone/MR signaling represents an important cause of disease as high plasma levels of aldosterone are associated with hypertension, obesity and increased cardiovascular risk. Aldosterone displays powerful vascular effects and acts as a potent pro-fibrotic agent in cardiovascular remodeling. Mineralocorticoid receptor activation regulates genes involved in vascular and cardiac fibrosis, calcification and inflammation. This review focuses on the role of novel potential biomarkers related to aldosterone/MR system that could help identify cardiovascular and metabolic detrimental conditions, as a result of altered MR activation. Specifically, we discuss: (1) how MR signaling regulates the number and function of different subpopulations of circulating and intra-tissue immune cells; (2) the role of aldosterone/MR system in mediating cardiometabolic diseases induced by obesity; and (3) the role of several MR downstream molecules as novel potential biomarkers of cardiometabolic diseases, end-organ damage and rehabilitation outcome.

Role of galectin-3 in subclinical myocardial impairment in psoriasis

BACKGROUND

Psoriasis has been shown to increase cardiovascular risk, and a contributor to this might be enhanced myocardial fibrosis promoted by the disease-associated pro-inflammatory milieu.

OBJECTIVE

We sought to investigate the relationship of galectin-3 (Gal-3) - a recognized mediator of fibrosis with inflammatory activation and left ventricular (LV) systolic and diastolic function in patients with psoriasis.

METHODS

We enrolled 102 psoriatic patients (mean age: 52.5 ± 12.6 years). Sixty-five age- and sex-matched healthy subjects served as controls. Echocardiographic assessment of myocardial function included estimation of LV longitudinal systolic deformation (GLS) and diastolic indices: tissue e' velocity and E/e' ratio. Laboratory measurements encompassed blood Gal-3, creatinine, glucose, insulin, CRP and erythrocyte sedimentation rate (ESR).

RESULTS

Patients with psoriasis were characterized by elevated Gal-3 (12.3 [9.3-13.4] vs. 6.3 [5.5-9.4] ng/mL in healthy controls, P < 0.001), ESR (17.0 [11.0-29.0] vs. 8.5 [6.0-13.0] mm, respectively, P < 0.001) and CRP (3.1 [1.7-10.6] vs. 1.9 [1.5-4.0] mg/L, respectively, P < 0.001), and reduced GLS (19.9 ± 3.7 vs. 22.0 ± 3.0%, respectively, P < 0.001). Progressive deterioration of GLS was demonstrated across Gal-3 tertiles. Significant associations between GLS and age (beta = -0.21, P < 0.04), Gal-3 (beta = -0.27, P < 0.01), CRP (beta = -0.22, P < 0.03), ESR (beta = -0.25, P < 0.01), waist circumference (beta = -0.22, P < 0.03) and waist-to-hip ratio (beta = -0.20, P < 0.05) were found. Stepwise multiple regression analysis revealed that the independent determinants of GLS in psoriatic patients were Gal-3 (beta = -0.24, P < 0.01) and ESR (beta = -0.21, P < 0.03). Regression-based mediation analysis demonstrated that the relationship between ESR and GLS was partially mediated by Gal-3.

CONCLUSIONS

Subclinical left ventricular systolic dysfunction in psoriasis, as evidenced by reduced GLS, is linked with the inflammatory upregulation, and enhanced profibrotic activity (as reflected by elevated serum Gal-3) may be involved in this process. These putative mechanisms may be responsible for the observed higher incidence of heart failure in this disease condition and should be considered as a potential target for preventive and therapeutic measures.

Galectin-3 down-regulates antioxidant peroxiredoxin-4 in human cardiac fibroblasts: a new pathway to induce cardiac damage

Galectin-3 (Gal-3) is increased in heart failure (HF) and promotes cardiac fibrosis and inflammation. We investigated whether Gal-3 modulates oxidative stress in human cardiac fibroblasts, in experimental animal models and in human aortic stenosis (AS). Using proteomics and immunodetection approaches, we have identified that Gal-3 down-regulated the antioxidant peroxiredoxin-4 (Prx-4) in cardiac fibroblasts. In parallel, Gal-3 increased peroxide, nitrotyrosine, malondialdehyde, and N-carboxymethyl-lysine levels and decreased total antioxidant capacity. Gal-3 decreased prohibitin-2 expression without modifying other mitochondrial proteins. Prx-4 silencing increased oxidative stress markers. In Gal-3-silenced cells and in heart from Gal-3 knockout mice, Prx-4 was increased and oxidative stress markers were decreased. Pharmacological inhibition of Gal-3 with modified citrus pectin restored cardiac Prx-4 as well as prohibitin-2 levels and improved oxidative status in spontaneously hypertensive rats. In serum from 87 patients with AS, Gal-3 negatively correlated with total antioxidant capacity and positively correlated with peroxide. In myocardial biopsies from 26 AS patients, Gal-3 up-regulation paralleled a decrease in Prx-4 and in prohibitin-2. Cardiac Gal-3 inversely correlated with Prx-4 levels in myocardial biopsies. These data suggest that Gal-3 decreased Prx-4 antioxidant system in cardiac fibroblasts, increasing oxidative stress. In pathological models presenting enhanced cardiac Gal-3, the decrease in Prx-4 expression paralleled increased oxidative stress. Gal-3 blockade restored Prx-4 expression and improved oxidative stress status. In AS, circulating levels of Gal-3 could reflect oxidative stress. The alteration of the balance between antioxidant systems and reactive oxygen species production could be a new pathogenic mechanism by which Gal-3 induces cardiac damage in HF.

Galectin-3 as a Predictor of Left Ventricular Reverse Remodeling in Recent-Onset Dilated Cardiomyopathy

Objectives

Studies have evaluated the association of galectin-3 and outcome in patients with heart failure. However, there is still scarce evidence concerning the clinical usefulness and predictive value of galectin-3 for left ventricular reverse remodeling (LVRR) in patients with recent-onset dilated cardiomyopathy (RODCM).

Patients and Methods

Baseline galectin-3 was measured in 57 patients with RODCM. All patients were followed for at least 12 months. The study end point was LVRR at 12 months, defined as an absolute improvement of the left ventricular ejection fraction of ≥10% to a final value of ≥35%, accompanied by a decrease in the left ventricular end diastolic diameter of at least 10%, as assessed by echocardiography. In receiver operating characteristic curve analysis, the optimum cut-off value for baseline galectin-3 with the highest Youden index was 59 ng/ml.

Results

Overall, LVRR at 12 months was observed in 38 patients (66%). In a univariate analysis, NYHA functional class and baseline galectin-3 levels were associated with LVRR. After adjustment for covariates, galectin-3 remained an independent predictor for LVRR.

Conclusions

Our study suggests that baseline galectin-3 is an independent predictor of LVRR. Low levels of galectin-3 may be regarded a useful biomarker of favorable ventricular remodeling in patients with RODCM.

GDF-15, Galectin 3, Soluble ST2, and Risk of Mortality and Cardiovascular Events in CKD

RATIONALE & OBJECTIVE

Inflammation, cardiac remodeling, and fibrosis may explain in part the excess risk for cardiovascular disease (CVD) in patients with chronic kidney disease (CKD). Growth differentiation factor 15 (GDF-15), galectin 3 (Gal-3), and soluble ST2 (sST2) are possible biomarkers of these pathways in patients with CKD.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

Individuals with CKD enrolled in either of 2 multicenter CKD cohort studies: the Seattle Kidney Study or C-PROBE (Clinical Phenotyping and Resource Biobank Study).

EXPOSURES

Circulating GDF-15, Gal-3, and sST2 measured at baseline.

OUTCOMES

Primary outcome was all-cause mortality. Secondary outcomes included hospitalization for physician-adjudicated heart failure and the atherosclerotic CVD events of myocardial infarction and cerebrovascular accident.

ANALYTIC APPROACH

Cox proportional hazards models used to test the association of each biomarker with each outcome, adjusting for demographics, CVD risk factors, and kidney function.

RESULTS

Among 883 participants, mean estimated glomerular filtration rate was 49±19mL/min/1.73m². Higher GDF-15 (adjusted HR [aHR] per 1-SD higher, 1.87; 95% CI, 1.53-2.29), Gal-3 (aHR per 1-SD higher, 1.51; 95% CI, 1.36-1.78), and sST2 (aHR per 1-SD higher, 1.36; 95% CI, 1.17-1.58) concentrations were significantly associated with mortality. Only GDF-15 level was also associated with heart failure events (HR per 1-SD higher, 1.56; 95% CI, 1.12-2.16). There were no detectable associations between GDF-15, Gal-3, or sST2 concentrations and atherosclerotic CVD events.

LIMITATIONS

Event rates for heart failure and atherosclerotic CVD were low.

CONCLUSIONS

Adults with CKD and higher circulating GDF-15, Gal-3, and sST2 concentrations experienced greater mortality. Elevated GDF-15 concentration was also associated with an increased rate of heart failure. Further work is needed to elucidate the mechanisms linking these circulating biomarkers with CVD in patients with CKD.

Biomarkers, myocardial fibrosis and co-morbidities in heart failure with preserved ejection fraction: an overview

The prevalence of heart failure with preserved ejection fraction (HFpEF) is steadily increasing. Its diagnosis remains difficult and controversial and relies mostly on non-invasive echocardiographic detection of left ventricular diastolic dysfunction and elevated filling pressures. The large phenotypic heterogeneity of HFpEF from pathophysiologic al underpinnings to clinical manifestations presents a major obstacle to the development of new therapies targeted towards specific HF phenotypes. Recent studies suggest that natriuretic peptides have the potential to improve the diagnosis of early HFpEF, but they still have significant limitations, and the cut-off points for diagnosis and prognosis in HFpEF remain open to debate. The purpose of this review is to present potential targets of intervention in patients with HFpEF, starting with myocardial fibrosis and methods of its detection. In addition, co-morbidities are discussed as a means to treat HFpEF according to cut-points of biomarkers that are different from usual. Biomarkers and approaches to co-morbidities may be able to tailor therapies according to patients' pathophysiological needs. Recently, soluble source of tumorigenicity 2 (sST2), growth differentiation factor 15 (GDF-15), galectin-3, and other cardiac markers have emerged, but evidence from large cohorts is still lacking. Furthermore, the field of miRNA is a very promising area of research, and further exploration of miRNA may offer diagnostic and prognostic applications and insight into the pathology, pointing to new phenotype-specific therapeutic targets.

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.

Mechanisms responsible for increased circulating levels of galectin-3 in cardiomyopathy and heart failure

Galectin-3 is a biomarker of heart disease. However, it remains unknown whether increase in galectin-3 levels is dependent on aetiology or disease-associated conditions and whether diseased heart releases galectin-3 into the circulation. We explored these questions in mouse models of heart disease and in patients with cardiomyopathy. All mouse models (dilated cardiomyopathy, DCM; fibrotic cardiomyopathy, ischemia-reperfusion, I/R; treatment with β-adrenergic agonist isoproterenol) showed multi-fold increases in cardiac galectin-3 expression and preserved renal function. In mice with fibrotic cardiomyopathy, I/R or isoproterenol treatment, plasma galectin-3 levels and density of cardiac inflammatory cells were elevated. These models also exhibited parallel changes in cardiac and plasma galectin-3 levels and presence of trans-cardiac galectin-3 gradient, indicating cardiac release of galectin-3. DCM mice showed no change in circulating galectin-3 levels nor trans-cardiac galectin-3 gradient or myocardial inflammatory infiltration despite a 50-fold increase in cardiac galectin-3 content. In patients with hypertrophic cardiomyopathy or DCM, plasma galectin-3 increased only in those with renal dysfunction and a trans-cardiac galectin-3 gradient was not present. Collectively, this study documents the aetiology-dependency and diverse mechanisms of increment in circulating galectin-3 levels. Our findings highlight cardiac inflammation and enhanced β-adrenoceptor activation in mediating elevated galectin-3 levels via cardiac release in the mechanism.

Galectin-3 in Heart Failure: An Update of the Last 3 Years

Galectin-3 plays a role in tissue inflammation, repair, and fibrosis. This article specifically focuses on heart failure (HF), in which galectin-3 has been shown to be a useful biomarker in prognosis and risk stratification, especially in HF with preserved ejection fraction. Experimental research has shown that galectin-3 directly induces pathologic remodeling of the heart, and is therefore considered a culprit protein in the development of cardiac fibrosis in HF, with potentially relevant clinical implications. In summary, galectin-3 is a biomarker and biotarget in cardiac remodeling and fibrosis and future research will target galectin-3-centered diseases.

Aldosterone Impairs Mitochondrial Function in Human Cardiac Fibroblasts via A-Kinase Anchor Protein 12

Aldosterone (Aldo) contributes to mitochondrial dysfunction and cardiac oxidative stress. Using a proteomic approach, A-kinase anchor protein (AKAP)-12 has been identified as a down-regulated protein by Aldo in human cardiac fibroblasts. We aim to characterize whether AKAP-12 down-regulation could be a deleterious mechanism which induces mitochondrial dysfunction and oxidative stress in cardiac cells. Aldo down-regulated AKAP-12 via its mineralocorticoid receptor, increased oxidative stress and induced mitochondrial dysfunction characterized by decreased mitochondrial-DNA and Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) expressions in human cardiac fibroblasts. CRISPR/Cas9-mediated knock-down of AKAP-12 produced similar deleterious effects in human cardiac fibroblasts. CRISPR/Cas9-mediated activation of AKAP-12 blunted Aldo effects on mitochondrial dysfunction and oxidative stress in human cardiac fibroblasts. In Aldo-salt-treated rats, cardiac AKAP-12, mitochondrial-DNA and PGC-1α expressions were decreased and paralleled increased oxidative stress. In myocardial biopsies from patients with aortic stenosis (AS, n = 26), AKAP-12, mitochondrial-DNA and PGC-1α expressions were decreased as compared to Controls (n = 13). Circulating Aldo levels inversely correlated with cardiac AKAP-12. PGC-1α positively associated with AKAP-12 and with mitochondrial-DNA. Aldo decreased AKAP-12 expression, impairing mitochondrial biogenesis and increasing cardiac oxidative stress. AKAP-12 down-regulation triggered by Aldo may represent an important event in the development of mitochondrial dysfunction and cardiac oxidative stress.

Enhanced cortical bone expansion in Lgals3-deficient mice during aging

Imbalances between bone formation and bone resorption, which can occur due to aging or sex hormone deprivation, result in decreased bone mass and an increased risk of fracture. Previous studies have suggested that the β-galactoside binding lectin, galectin-3, is involved in bone remodeling. We compared bone parameters of mice having null alleles of the galectin-3 gene (Lgals3-KO) with those of their wild-type littermates. Lgals3 deficiency increased cortical bone expansion at 36 weeks (wk) and preserved or enhanced bone mass in both male and female mutant mice. In addition, female Lgals3-KO mice were protected from age-related loss of trabecular bone. Histomorphometry and ex vivo primary cell differentiation assays showed increased osteoblastogenesis with little-to-no effect on osteoclastogenesis, suggesting the increased bone mass phenotype is primarily due to increased anabolism. Our study identifies galectin-3 as a negative regulator of bone formation and suggests that disruption of galectin-3 may be useful in preventing bone loss during aging.

Researchers have identified a promising new drug target to reduce bone loss during aging, a protein called galectin-3. Bones undergo lifelong remodeling via resorption of old bone and generation of new bone. With aging, the balance tips towards resorption, weakening bones. Galectin-3 was known to be involved in bone remodeling and levels increased with age. Bart Williams and co-workers at the Van Andel Research Institute in Grand Rapids, USA, investigated whether the age-related increase in galectin-3 increased bone loss. Using mice lacking the gene encoding galectin-3, the researchers measured bone mass at different ages. In older mice, bone mass was preserved or even enhanced. Further investigation of bone cells showed the increase was probably due to increased bone formation, rather than decreased bone resorption. The researchers conclude that disrupting galectin-3 may help to prevent aging-related bone loss.

Galectin-3 in Atrial Fibrillation: Mechanisms and Therapeutic Implications

Maintenance of atrial fibrillation is a complex mechanism, including extensive electrical and structural remodeling of the atria which involves progressive fibrogenesis. Galectin-3 is a biomarker of fibrosis, and, thus, may be involved in atrial remodeling in atrial fibrillation patients. We review the role of galectin-3 in AF mechanisms and its potential therapeutic implications.

Plasma galectin-3 concentrations in patients with primary aldosteronism

BACKGROUND

The incidence of cardiovascular events is higher in patients with primary aldosteronism than in patients with essential hypertension (EHT), despite similar blood pressure levels. This suggests detrimental cardiovascular effects of aldosterone. Amongst others, it has been suggested that galectin-3 (Gal-3) is a key mediator in aldosterone-induced myocardial fibrosis.

OBJECTIVE

We studied whether patients with primary aldosteronism have higher plasma Gal-3 concentrations than patients with EHT and evaluated its reversibility after adrenalectomy.

METHODS

In a retrospective cohort from our tertiary referral centre, we measured plasma Gal-3 concentrations in 78 patients with primary aldosteronism, 39 cured primary aldosteronism patients after adrenalectomy and 56 patients with EHT. Paired samples were available in 11 patients (preadrenalectomy and postadrenalectomy). We compared plasma Gal-3 levels by univariate analysis of covariance with correction for cardiovascular risk factors, plasma creatinine concentration, plasma potassium levels and alcohol intake.

RESULTS

Adjusted plasma Gal-3 concentrations in patients with primary aldosteronism, patients after adrenalectomy and patients with EHT were 11.39 ± 0.60, 11.64 ± 0.81 and 11.41 ± 0.73 ng/ml, respectively (mean ± SD; P = 0.95). In 11 patients of whom paired samples were available, mean Gal-3 concentrations increased from 10.03 ± 1.67 ng/ml preadrenalectomy to 14.36 ± 2.07 ng/ml postadrenalectomy (P < 0.01).

CONCLUSION

In patients with primary aldosteronism, plasma Gal-3 concentrations are not elevated when compared with patients with EHT, and levels do not decrease after adrenalectomy. These results are in contrast to previous studies and do not support a pathophysiological role of plasma Gal-3 in the increased cardiovascular risk in patients with primary aldosteronism.