Galectin-3 mediates aldosterone-induced vascular fibrosis

Inhibition of galectin-3 ameliorates the consequences of cardiac lipotoxicity in a rat model of diet-induced obesity

Obesity is accompanied by metabolic alterations characterized by insulin resistance and cardiac lipotoxicity. Galectin-3 (Gal-3) induces cardiac inflammation and fibrosis in the context of obesity; however, its role in the metabolic consequences of obesity is not totally established. We have investigated the potential role of Gal-3 in the cardiac metabolic disturbances associated with obesity. In addition, we have explored whether this participation is, at least partially, acting on mitochondrial damage. Gal-3 inhibition in rats that were fed a high-fat diet (HFD) for 6 weeks with modified citrus pectin (MCP; 100 mg/kg/day) attenuated the increase in cardiac levels of total triglyceride (TG). MCP treatment also prevented the increase in cardiac protein levels of carnitine palmitoyl transferase IA, mitofusin 1, and mitochondrial complexes I and II, reactive oxygen species accumulation and decrease in those of complex V but did not affect the reduction in ¹⁸F-fluorodeoxyglucose uptake observed in HFD rats. The exposure of cardiac myoblasts (H9c2) to palmitic acid increased the rate of respiration, mainly due to an increase in the proton leak, glycolysis, oxidative stress, β-oxidation and reduced mitochondrial membrane potential. Inhibition of Gal-3 activity was unable to affect these changes. Our findings indicate that Gal-3 inhibition attenuates some of the consequences of cardiac lipotoxicity induced by a HFD since it reduced TG and lysophosphatidyl choline (LPC) levels. These reductions were accompanied by amelioration of the mitochondrial damage observed in HFD rats, although no improvement was observed regarding insulin resistance. These findings increase the interest for Gal-3 as a potential new target for therapeutic intervention to prevent obesity-associated cardiac lipotoxicity and subsequent mitochondrial dysfunction.

Summary: Inhibition of Gal-3 activity reduced the excessive cardiac accumulation of lipids in rats fed a high fat diet. This was accompanied by the amelioration of mitochondria damage observed in obese rats.

Is galectin-3 a promoter of ventricular dysfunction?

Heart failure is nowadays a common condition associated with high mortality and increased healthcare-related costs. Over the years, the research on heart failure management has been extensive in order to better diagnose and treat the condition. Since the progression of left ventricular dysfunction is a consequence of myocardial inflammation, apopotosis, and fibrosis leading to myocardium remodelling, several molecules that are involved in the inflammation pathways have been explored as possible biomarkers for the condition. The study of biomarkers and their key roles in inflammation could allow early identification of patients with heart failure, improve prognostic assessment, and provide a target for future therapies. Among currently studied biomarkers, extensive research has been conducted on galectin-3, a galactoside-binding lectin, which is synthetised and secreted when cardiomyocytes and fibroblasts are submitted to mechanical stress. Accordingly, it has been hypothesised that galectin-3 could be a promoter of left ventricular dysfunction. Galectin-3 has been shown to mediate inflammation by several different pathways which are further detailed in the current review. Also, we aimed to provide a comprehensive overview of existing evidence on the utility of galectin-3 in clinical settings associated with heart failure.

Proteome and Metabolome of Subretinal Fluid in Central Serous Chorioretinopathy and Rhegmatogenous Retinal Detachment: A Pilot Case Study

PURPOSE

To investigate the molecular composition of subretinal fluid (SRF) in central serous chorioretinopathy (CSCR) and rhegmatogenous retinal detachment (RRD) using proteomics and metabolomics.

METHODS

SRF was obtained from one patient with severe nonresolving bullous CSCR requiring surgical subretinal fibrin removal, and two patients with long-standing RRD. Proteins were trypsin-digested, labeled with Tandem-Mass-Tag and fractionated according to their isoelectric point for identification and quantification by tandem mass spectrometry. Independently, metabolites were extracted on cold methanol/ethanol, and identified by untargeted ultra-high performance liquid chromatography and high-resolution mass spectrometry. Bioinformatics analyses were conducted.

RESULTS

In total, 291 proteins and 651 metabolites were identified in SRF samples. Compared with RRD, 128 proteins (77 downregulated; 51 upregulated) and 76 metabolites (43 downregulated; 33 upregulated) differed in the SRF from CSCR. Protein and metabolites notably deregulated in CSCR were related to glycolysis/gluconeogenesis, inflammation (including serum amyloid P component, versican), alternative complement pathway (complement factor H and complement factor H-related protein), cellular adhesion, biliary acid metabolism (farnesoid X receptor/retinoid X receptor), and gluco- and mineralocorticoid systems (aldosterone, angiotensin, and corticosteroid-binding globulin).

CONCLUSIONS

Proteomics and metabolomics can be performed on SRF. A unique SRF sample from CSCR exhibited a distinct molecular profile compared with RRD.

TRANSLATIONAL RELEVANCE

This first comparative multiomics analysis of SRF improved the understanding of CSCR and RRD pathophysiology. It identified pathways potentially involved in the better photoreceptor preservation in CSCR, suggesting neuroprotective targets that will require additional confirmation.

Clinical Phenotyping of Heart Failure with Biomarkers: Current and Future Perspectives

INTRODUCTION

Heart failure (HF) is a complex clinical syndrome with diverse risk factors and etiologies, differing underlying pathophysiology, and large phenotypic heterogeneity.

RECENT FINDINGS

Advances in imaging techniques coupled with clinical trials that targeted only in those with impaired left ventricular ejection fraction (LVEF) have largely shaped the current management strategy for HF that focuses predominantly in patients with systolic HF. In contrast, there are no effective treatments for HF with preserved ejection fraction (HFpEF). Instead of this "one-size-fits-all" approach to treatment, better precision to define HF phenotypic classifications may lead to more efficient and effective HF disease management.

CONCLUSION

Integrating variables-including clinical variables, HF biomarkers, imaging, genotypes, metabolomics, and proteomics-can identify different pathophysiologies, lead to more precise phenotypic classification, and warrant investigation in future clinical trials.

Increased galectin-3 levels are associated with abdominal aortic aneurysm progression and inhibition of galectin-3 decreases elastase-induced AAA development

Abdominal aortic aneurysm (AAA) evolution is unpredictable and no specific treatment exists for AAA, except surgery to prevent aortic rupture. Galectin-3 has been previously associated with CVD, but its potential role in AAA has not been addressed. Galectin-3 levels were increased in the plasma of AAA patients (n=225) compared with the control group (n=100). In addition, galectin-3 concentrations were associated with the need for surgical repair, independently of potential confounding factors. Galectin-3 mRNA and protein expression were increased in human AAA samples compared with healthy aortas. Experimental AAA in mice was induced via aortic elastase perfusion. Mice were treated intravenously with the galectin-3 inhibitor modified citrus pectin (MCP, 10 mg/kg, every other day) or saline. Similar to humans, galectin-3 serum and aortic mRNA levels were also increased in elastase-induced AAA mice compared with control mice. Mice treated with MCP showed decreased aortic dilation, as well as elastin degradation, vascular smooth muscle cell (VSMC) loss, and macrophage content at day 14 postelastase perfusion compared with control mice. The underlying mechanism(s) of the protective effect of MCP was associated with a decrease in galectin-3 and cytokine (mainly CCL5) mRNA and protein expression. Interestingly, galectin-3 induced CCL5 expression by a mechanism involving STAT3 activation in VSMC. Accordingly, MCP treatment decreased STAT3 phosphorylation in elastase-induced AAA. In conclusion, increased galectin-3 levels are associated with AAA progression, while galectin-3 inhibition decreased experimental AAA development. Our data suggest the potential role of galectin-3 as a therapeutic target in AAA.

Association of Serum Galectin-3 with the Acute Exacerbation of Chronic Obstructive Pulmonary Disease

BACKGROUND Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) aggravates the overall severity in COPD patients, resulting in severe morbidity and mortality. However, there are no objective biomarkers currently available to predict the development of AECOPD. Several studies have indicated that galectin-3 (Gal-3) is involved in diseases characterized by excessive inflammatory response and fibrosis. The objective of this study was to examine the dynamic changes of Gal-3 in acute exacerbation and convalescence phases of COPD. MATERIAL AND METHODS Serum levels of Gal-3, high sensitivity C-reactive protein (hsCRP), and prohormone of brain natriuretic peptide (pro-BNP) were determined using multiplex enzyme-linked immunosorbent assay kits. Serum levels of Gal-3 in 44 patients with COPD were further analyzed and correlated with the parameters of lung function and the biomarkers of systemic inflammation. RESULTS The mean level of serum Gal-3 was significantly higher in acute exacerbation of COPD compared with the level in COPD convalescence phase (32.10±9.83 versus 29.02±8.68 ng/mL, p<0.01). Serum levels of Gal-3 positively correlated with hsCRP (r=0.354, p=0.018 for total patients) and pro-BNP (r=0.319, p=0.035 for total patients) in AECOPD. In addition, the level of Gal-3 was the highest in the current smoker group, and the lowest in the never-smoker group in either the acute exacerbation phase (33.91±3.55 versus 29.12±11.73 ng/mL, p=0.036) or the convalescence phase (30.94±3.40 versus 27.76±9.68 ng/mL, p=0.045) of COPD. CONCLUSIONS Our results indicated that serum Gal-3 is increased in AECOPD patients, which is also positively associated with systemic inflammation and smoking in patients with COPD, suggesting that Gal-3 might be a valuable biomarker for AECOPD.

Galectin-3 in acute coronary syndrome

Acute coronary syndrome (ACS) is a very common cause of hospitalizations worldwide each year. In the past decades biomarkers have become an indispensable tool for diagnosis, risk stratification and prognosis of cardiovascular disease, including ACS. Despite Troponin is considered the gold standard in diagnosis of ACS, several molecules have been investigated to identify predictive biomarkers of prognosis. Among these, Gal-3 has emerged as a promising prognostic marker. It has a pivotal role in inflammation and fibrosis. Both experimental and clinical studies have shown Gal-3 is an independent predictor of all-cause mortality, cardiovascular death and occurrence of HF following ACS. This article reviews the literature data regarding the role of Galectin-3 in ACS setting.

Plasma galectin-3 levels are associated with the risk of incident chronic kidney disease

Galectin-3 has been proposed as a novel biomarker of heart failure and cardiac fibrosis, and may also be associated with fibrosis of other organs such as the kidney. To determine this, we prospectively analyzed data from 9,148 Atherosclerosis Risk in Communities (ARIC) Study participants with measured plasma galectin-3 levels (baseline, visit 4, 1996-98) and without prevalent chronic kidney disease (CKD) or heart failure. We identified 1,983 incident CKD cases through December 31, 2013 over a median follow-up of 16 years. At baseline, galectin-3 was cross-sectionally associated with estimated glomerular filtration rate and urine albumin-to-creatinine ratio; both significant. The results were adjusted for age, sex, race-center, education, physical activity, smoking status, body mass index, systolic blood pressure, anti-hypertensive medication use, history of cardiovascular disease, diabetes, fasting blood glucose, and rs4644 (a single nucleotide polymorphism of galactin-3). There was a significant, graded, and positive association between galectin-3 and incident CKD (quartile 4 vs. 1 hazard ratio: 2.22 [95% confidence interval: 1.89, 2.60]). The association was attenuated but remained significant after adjustment for estimated glomerular filtration rate, urine albumin-to-creatinine ratio, troponin T, and N-terminal pro-brain natriuretic peptide (quartile 4 vs. 1 hazard ratio: 1.75 [95% confidence interval: 1.49, 2.06]), and was stronger among those with hypertension at baseline (significant interaction). Thus, in this community-based population, higher plasma galectin-3 levels were associated with an elevated risk of developing incident CKD, particularly among those with hypertension.

Synergistic Antioxidant and Anti-Inflammatory Effects between Modified Citrus Pectin and Honokiol

Inflammation is a normal physiological process; however, dysregulation of this process may contribute to inflammatory-based chronic disorders and diseases in animals and humans. Therefore, the antioxidant and anti-inflammatory properties of natural products, often recognized in traditional medicine systems, represent therapeutic modalities to reduce or prevent uncontrolled inflammatory processes which in turn potentially ameliorate or prevent sequelae of inflammatory-based symptoms of chronic diseases. We have investigated the antioxidant and anti-inflammatory effects of honokiol (HNK) and modified citrus pectin (MCP) in vitro and examined whether the MCP : HNK combination has synergistic effects on antioxidant and anti-inflammatory properties. Although both HNK and MCP induced a dose-dependent increase in antioxidant activity, the latter has a consistently higher antioxidant effect. The MCP : HNK (9 : 1) combination induced a synergistic effect on antioxidant activity suggesting that the combination is significantly more efficacious than individual compounds. In mouse monocytes, the lipopolysaccharide- (LPS-) induced tumor necrosis-α (TNF-α) synthesis was significantly inhibited by HNK and the MCP : HNK combination in a dose-dependent manner and synergistic effects were clearly demonstrated with the combination on TNF-α inhibition. This combination effect was also evident on inhibition of nuclear factor-kappa B activity, cyclooxygenase-II activity, and lipid peroxidation in mouse monocytes. Further research into the combination is warranted.

Randomized Controlled Trial of Mineralocorticoid Receptor Blockade in Children with Chronic Kidney Allograft Nephropathy

BACKGROUND AND OBJECTIVES

We showed that mineralocorticoid receptor blockade (MRB) prevented acute and chronic cyclosporine nephropathy (CsA-Nx) in the rat. The aim of this translational study was to investigate the effect of long-term eplerenone administration on renal allograft function in children with biopsy-proven chronic allograft nephropathy (CAN).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Renal transplant children <18 years, biopsy-proven CAN, and a GFR>40 ml/min per 1.73 m2 were included. Patients with BK virus active nephritis, recurrence of renal disease, GFR decline in previous 3 months, or treated with calcium antagonists or antifungal drugs were excluded. They were randomized to receive placebo (n=10) or eplerenone 25 mg/d for 24 months (n=13). Visits were scheduled at baseline, 6, 12, and 24 months. At each period, a complete clinical examination was performed and blood and urine samples were taken. Urine creatinine, 8-hydroxylated-guanosine, heat shock protein 72 (HSP72), and kidney injury molecule (KIM-1) levels were also assessed. In kidney biopsy samples, the tubulo-interstitial area affected by fibrosis (TIF) and glomerulosclerosis were measured at baseline and after 24 months.

RESULTS

The baseline eGFR was 80±6 in the placebo and 86±6 ml/min per 1.73 m2 in the eplerenone group; at 24 months it was 66±8 and 81±7 ml/min per 1.73 m2, respectively (P=0.33; 95% confidence intervals, -18 to 33 at baseline, and -11 to 40 after 24 months). The albumin-to-creatinine ratio was 110±74 in the placebo, and 265±140 mg/g in the eplerenone group; and after 24 months it was 276±140 and 228±88 mg/g, respectively (P=0.15; 95% confidence intervals, -283 to 593, and -485 to 391, respectively). In addition, the placebo exhibited a greater TIF, glomerulosclerosis, and urinary HSP72 compared with the eplerenone group.

CONCLUSIONS

Although this study was underpowered to provide definitive evidence that long-term eplerenone administration attenuates the progression of CAN in pediatric transplant patients, it encourages testing the potential benefit of MRB in this pediatric population.

Beneficial Effects of Galectin-3 Blockade in Vascular and Aortic Valve Alterations in an Experimental Pressure Overload Model

Galectin-3 (Gal-3) is involved in cardiovascular fibrosis and aortic valve (AV) calcification. We hypothesized that Gal-3 pharmacological inhibition with modified citrus pectin (MCP) could reduce aortic and AV remodeling in normotensive rats with pressure overload (PO). Six weeks after aortic constriction, vascular Gal-3 expression was up-regulated in male Wistar rats. Gal-3 overexpression was accompanied by an increase in the aortic media layer thickness, enhanced total collagen, and augmented expression of fibrotic mediators. Further, vascular inflammatory markers as well as inflammatory cells content were greater in aorta from PO rats. MCP treatment (100 mg/kg/day) prevented the increase in Gal-3, media thickness, fibrosis, and inflammation in the aorta of PO rats. Gal-3 levels were higher in AVs from PO rats. This paralleled enhanced AV fibrosis, inflammation, as well as greater expression of calcification markers. MCP treatment prevented the increase in Gal-3 as well as fibrosis, inflammation, and calcification in AVs. Overall, Gal-3 is overexpressed in aorta and AVs from PO rats. Gal-3 pharmacological inhibition blocks aortic and AV remodeling in experimental PO. Gal-3 could be a new therapeutic approach to delay the progression and the development of aortic remodeling and AV calcification in PO.

Galectin-3 mediates pulmonary vascular remodeling in hypoxia-induced pulmonary arterial hypertension

Pulmonary vascular adventitia serves as a key regulator of pulmonary vascular remodeling in the pathogenesis of pulmonary arterial hypertension (PAH). Excessive proliferation and differentiation of pulmonary adventitial fibroblasts (PAFs) are proven to be crucial in the pathogenesis of PAH. Galectin-3 (Gal-3) is known as a key fibroblasts activating factor which is involved in the fibrogenesis of several diseases, such as pulmonary fibrosis, vascular fibrosis, and heart failure. Therefore, we seek to investigate the potential role of Gal-3 in regulating PAF cells in the pathogenesis of PAH. Gal-3 plasma concentration was significantly higher in PAH patients. Gal-3 was upregulated in pulmonary artery adventitia of hypoxia-induced PAH rats. Inhibition of Gal-3 with N-Acetyl-D-lactosamine (N-Lac) ameliorated PAH and pulmonary vascular remodeling. Gal-3 can stimulate the proliferation, differentiation, and collagen synthesis of PAFs, which was reversed by N-Lac. Transforming growth factor β1 increased Gal-3 expression in PAFs, whereas N-Lac significantly suppressed transforming growth factor β1-induced proliferation, differentiation, and collagen synthesis of PAFs. Gal-3 serves as a critical regulator in the pathogenesis of PAH by regulating the proliferation, differentiation, and extracellular matrix deposition synthesis of PAFs. Inhibition of Gal-3 may represent a novel therapeutic target for PAH treatment.

Galectin-3 Inhibition by a Small-Molecule Inhibitor Reduces Both Pathological Corneal Neovascularization and Fibrosis

Purpose

Corneal neovascularization and scarring commonly lead to significant vision loss. This study was designed to determine whether a small-molecule inhibitor of galectin-3 can inhibit both corneal angiogenesis and fibrosis in experimental mouse models.

Methods

Animal models of silver nitrate cautery and alkaline burn were used to induce mouse corneal angiogenesis and fibrosis, respectively. Corneas were treated with the galectin-3 inhibitor, 33DFTG, or vehicle alone and were processed for whole-mount immunofluorescence staining and Western blot analysis to quantify the density of blood vessels and markers of fibrosis. In addition, human umbilical vein endothelial cells (HUVECs) and primary human corneal fibroblasts were used to analyze the role of galectin-3 in the process of angiogenesis and fibrosis in vitro.

Results

Robust angiogenesis was observed in silver nitrate-cauterized corneas on day 5 post injury, and markedly increased corneal opacification was demonstrated in alkaline burn-injured corneas on days 7 and 14 post injury. Treatment with the inhibitor substantially reduced corneal angiogenesis and opacification with a concomitant decrease in α-smooth muscle actin (α-SMA) expression and distribution. In vitro studies revealed that 33DFTG inhibited VEGF-A-induced HUVEC migration and sprouting without cytotoxic effects. The addition of exogenous galectin-3 to corneal fibroblasts in culture induced the expression of fibrosis-related proteins, including α-SMA and connective tissue growth factor.

Conclusions

Our data provide proof of concept that targeting galectin-3 by the novel, small-molecule inhibitor, 33DFTG, ameliorates pathological corneal angiogenesis as well as fibrosis. These findings suggest a potential new therapeutic strategy for treating ocular disorders related to pathological angiogenesis and fibrosis.

Cardiac Fibrosis and Arrhythmogenesis

Myocardial injury, mechanical stress, neurohormonal activation, inflammation, and/or aging all lead to cardiac remodeling, which is responsible for cardiac dysfunction and arrhythmogenesis. Of the key histological components of cardiac remodeling, fibrosis either in the form of interstitial, patchy, or dense scars, constitutes a key histological substrate of arrhythmias. Here we discuss current research findings focusing on the role of fibrosis, in arrhythmogenesis. Numerous studies have convincingly shown that patchy or interstitial fibrosis interferes with myocardial electrophysiology by slowing down action potential propagation, initiating reentry, promoting after-depolarizations, and increasing ectopic automaticity. Meanwhile, there has been increasing appreciation of direct involvement of myofibroblasts, the activated form of fibroblasts, in arrhythmogenesis. Myofibroblasts undergo phenotypic changes with expression of gap-junctions and ion channels thereby forming direct electrical coupling with cardiomyocytes, which potentially results in profound disturbances of electrophysiology. There is strong evidence that systemic and regional inflammatory processes contribute to fibrogenesis (i.e., structural remodeling) and dysfunction of ion channels and Ca2+ homeostasis (i.e., electrical remodeling). Recognizing the pivotal role of fibrosis in the arrhythmogenesis has promoted clinical research on characterizing fibrosis by means of cardiac imaging or fibrosis biomarkers for clinical stratification of patients at higher risk of lethal arrhythmia, as well as preclinical research on the development of antifibrotic therapies. At the end of this review, we discuss remaining key questions in this area and propose new research approaches. © 2017 American Physiological Society. Compr Physiol 7:1009-1049, 2017.

Vascular dysfunction and fibrosis in stroke-prone spontaneously hypertensive rats: The aldosterone-mineralocorticoid receptor-Nox1 axis

AIMS

We questioned whether aldosterone and oxidative stress play a role in vascular damage in severe hypertension and investigated the role of Nox1 in this process.

MATERIALS AND METHODS

We studied mesenteric arteries, aortas and vascular smooth muscle cells (VSMC) from WKY and SHRSP rats. Vascular effects of eplerenone or canrenoic acid (CA) (mineralocorticoid receptor (MR) blockers), ML171 (Nox1 inhibitor) and EHT1864 (Rac1/2 inhibitor) were assessed. Nox1-knockout mice were also studied. Vessels and VSMCs were probed for Noxs, reactive oxygen species (ROS) and pro-fibrotic/inflammatory signaling.

KEY FINDINGS

Blood pressure and plasma levels of aldosterone and galectin-3 were increased in SHRSP versus WKY. Acetylcholine-induced vasorelaxation was decreased (61% vs 115%) and phenylephrine-induced contraction increased in SHRSP versus WKY (Emax 132.8% vs 96.9%, p<0.05). Eplerenone, ML171 and EHT1864 attenuated hypercontractility in SHRSP. Vascular expression of collagen, fibronectin, TGFβ, MCP-1, RANTES, MMP2, MMP9 and p66Shc was increased in SHRSP versus WKY. These changes were associated with increased ROS generation, 3-nitrotyrosine expression and Nox1 upregulation. Activation of vascular p66Shc and increased expression of Nox1 and collagen I were prevented by CA in SHRSP. Nox1 expression was increased in aldosterone-stimulated WKY VSMCs, an effect that was amplified in SHRSP VSMCs (5.2vs9.9 fold-increase). ML171 prevented aldosterone-induced VSMC Nox1-ROS production. Aldosterone increased vascular expression of fibronectin and PAI-1 in wild-type mice but not in Nox1-knockout mice.

SIGNIFICANCE

Our findings suggest that aldosterone, which is increased in SHRSP, induces vascular damage through MR-Nox1-p66Shc-mediated processes that modulate pro-fibrotic and pro-inflammatory signaling pathways.

Potential novel biomarkers of cardiovascular dysfunction and disease: cardiotrophin-1, adipokines and galectin-3

Cardiovascular disease is one of the main burdens of healthcare systems worldwide. Nevertheless, assessing cardiovascular risk in both apparently healthy individuals and low/high-risk patients remains a difficult issue. Already established biomarkers (e.g. brain natriuretic peptide, troponin) have significantly improved the assessment of major cardiovascular events and diseases but cannot be applied to all patients and in some cases do not provide sufficiently accurate information. In this context, new potential biomarkers that reflect various underlying pathophysiological cardiac and vascular modifications are needed. Also, a multiple biomarker evaluation that shows changes in the cardiovascular state is of interest. This review describes the role of selected markers of vascular inflammation, atherosclerosis, atherothrombosis, endothelial dysfunction and cardiovascular fibrosis in the pathogenesis and prognosis of cardiovascular disease: the potential use of cardiotrophin-1, leptin, adiponectin, resistin and galectin-3 as biomarkers for various cardiovascular conditions is discussed.

High Expression of Galectin-3 in Patients with IgG4-Related Disease: A Proteomic Approach

Objectives

Immunoglobulin G4-related disease (IgG4-RD) is a multiorgan condition manifesting itself in different forms. This study aimed to investigate protein expression profiles and to find the possible biomarker for IgG4-RD by liquid chromatography mass spectrometry (LC-MS) using tissue sections in IgG4-RD patients.

Methods

Protein expression profiles in five IgG4-related pancreatitis and three normal pancreatic samples were compared using LC-MS and were validated by quantitative real-time PCR (qRT-PCR), immunoblotting, and immunohistochemistry. ELISA was employed in the serum of 20 patients with systemic IgG4-RD before and during steroid treatment.

Results

LC-MS indicated that the levels of 17 proteins were significantly higher and 12 others were significantly lower in IgG4-related pancreatitis patients compared to controls. Among these proteins, galectin-3 levels were 13-fold higher in IgG4-related pancreatitis (P < 0.01). These results were confirmed by immunoblotting and qRT-PCR. The average number of galectin-3 + cells in various organs of IgG4-RD patients, including salivary glands, lungs, and lymph nodes, was higher than in controls. Galectin-3 was detectable in macrophages, dendritic cells, and stromal myofibroblast-like cells, but not in lymphocytes by immunofluorescence staining. Serum galectin-3 levels were higher in patients with IgG4-RD compared with healthy donors and remained high during steroid therapy.

Conclusion

Galectin-3 was overexpressed in IgG4-RD and the levels were indirectly related to clinical activity.

Novel Risk Markers and Risk Assessments for Cardiovascular Disease

The use of risk markers has transformed cardiovascular medicine, exemplified by the routine assessment of troponin, for both diagnosis and assessment of prognosis in patients with chest pain. Clinical risk factors form the basis for risk assessment of cardiovascular disease and the addition of biochemical, cellular, and imaging parameters offers further refinement. Identifying novel risk factors may allow greater risk stratification and a steady, but gradual progression toward precision medicine. Indeed, the generation of data in this area of research is explosive and when combined with new technologies and techniques provides the potential for more refined, targeted approaches to cardiovascular medicine. Although discussing the most recent developments in this field, this review article aims to strike a balance between novelty and validity by focusing on recent large sample-size studies that have been validated in a separate cohort in most cases. Risk markers related to atherosclerosis, thrombosis, inflammation, cardiac injury, and fibrosis are introduced in the context of their pathophysiology. Rapidly developing new areas, such as assessment of micro-RNA, are also explored. Subsequently the prognostic ability of these risk markers in coronary artery disease, heart failure, and atrial fibrillation is discussed in detail.

A role for galectin-3 in the development of early molecular alterations in short-term aortic stenosis

Aortic stenosis (AS) is characterized by pressure overload and causes left ventricular (LV) fibrosis and inflammation, two mechanisms that eventually lead to cardiac dysfunction. Galectin-3 (Gal-3), a β-galactoside-binding lectin, promotes cardiac remodelling. In the present study, we investigated the role of Gal-3 in LV remodelling in patients with AS and the effects of Gal-3 blockade in rats subjected to short-term (6-week) supravalvular aortic banding (AS group). Myocardial biopsies were obtained from 25 patients with severe AS referred for aortic valve replacement and from necropsies of 11 cardiovascular disease-free control individuals. Gal-3 was up-regulated in myocardial biopsies from AS patients compared with controls. Gal-3 directly correlated with parameters assessing myocardial fibrosis and inflammation in AS patients. Normotensive AS animals presented decreased LV diastolic diameter compared with controls. At the histological level, AS rats exhibited a slight increase in LV cross-sectional area and LV wall thickness, and augmented cardiomyocyte width and cross-sectional area. AS animals presented enhanced cardiac Gal-3 expression, which paralleled higher myocardial fibrosis and inflammation. Cardiac Gal-3 was associated with fibrosis and inflammatory markers. Gal-3 pharmacological inhibition prevented the increase in cardiac Gal-3 and normalized histological and molecular alterations in AS rats. In short-term AS, the increase in myocardial Gal-3 expression was associated with cardiac fibrosis and inflammation, alterations that were prevented by Gal-3 blockade. These data suggest that Gal-3 inhibition could be a novel therapeutic approach in the prevention of AS-associated early pathological cardiac remodelling.

PPARγ Links BMP2 and TGFβ1 Pathways in Vascular Smooth Muscle Cells, Regulating Cell Proliferation and Glucose Metabolism

BMP2 and TGFβ1 are functional antagonists of pathological remodeling in the arteries, heart, and lung; however, the mechanisms in VSMCs, and their disturbance in pulmonary arterial hypertension (PAH), are unclear. We found a pro-proliferative TGFβ1-Stat3-FoxO1 axis in VSMCs, and PPARγ as inhibitory regulator of TGFβ1-Stat3-FoxO1 and TGFβ1-Smad3/4, by physically interacting with Stat3 and Smad3. TGFβ1 induces fibrosis-related genes and miR-130a/301b, suppressing PPARγ. Conversely, PPARγ inhibits TGFβ1-induced mitochondrial activation and VSMC proliferation, and regulates two glucose metabolism-related enzymes, platelet isoform of phosphofructokinase (PFKP, a PPARγ target, via miR-331-5p) and protein phosphatase 1 regulatory subunit 3G (PPP1R3G, a Smad3 target). PPARγ knockdown/deletion in VSMCs activates TGFβ1 signaling. The PPARγ agonist pioglitazone reverses PAH and inhibits the TGFβ1-Stat3-FoxO1 axis in TGFβ1-overexpressing mice. We identified PPARγ as a missing link between BMP2 and TGFβ1 pathways in VSMCs. PPARγ activation can be beneficial in TGFβ1-associated diseases, such as PAH, parenchymal lung diseases, and Marfan's syndrome.

Clinical Correlates and Prognostic Value of Plasma Galectin-3 Levels in Degenerative Aortic Stenosis: A Single-Center Prospective Study of Patients Referred for Invasive Treatment

Galectin-3 (Gal-3), a β-galactoside-binding lectin, has been implicated in myocardial fibrosis, development of left ventricular (LV) dysfunction and transition from compensated LV hypertrophy to overt heart failure (HF), being a novel prognostic marker in HF. Risk stratification is crucial for the choice of the optimal therapy in degenerative aortic stenosis (AS), affecting elderly subjects with coexistent diseases. Our aim was to assess correlates and prognostic value of circulating Gal-3 in real-world patients with degenerative AS referred for invasive treatment. Gal-3 levels were measured at admission in 80 consecutive patients with symptomatic degenerative AS (mean age: 79 ± 8 years; aortic valve area (AVA) index: 0.4 ± 0.1 cm²/m²). The therapeutic strategy was chosen following a dedicated multidisciplinary team-oriented approach, including surgical valve replacement (n = 11), transcatheter valve implantation (n = 19), balloon aortic valvuloplasty (BAV) (n = 25) and optimal medical therapy (n = 25). Besides routine echocardiographic indices, valvulo-arterial impedance (Zva), an index of global LV afterload, was computed. There were 22 deaths over a median follow-up of 523 days. Baseline Gal-3 correlated negatively with estimated glomerular filtration rate (eGFR) (r = -0.61, p < 0.001) and was unrelated to age, symptomatic status, AVA index, LV ejection fraction, LV mass index or Zva. For the study group as a whole, Gal-3 tended to predict mortality (Gal-3 >17.8 vs. Gal-3 <17.8 ng/mL; hazard ratio (HR): 2.03 (95% confidence interval, 0.88-4.69), p = 0.09), which was abolished upon adjustment for eGFR (HR: 1.70 (0.61-4.73), p = 0.3). However, in post-BAV patients multivariate-adjusted pre-procedural Gal-3 was associated with worse survival (HR: 7.41 (1.52-36.1), p = 0.01) regardless of eGFR. In conclusion, the inverse eGFR-Gal-3 relationship underlies a weak association between Gal-3 and adverse outcome in patients with degenerative AS referred for invasive therapy irrespective of type of treatment employed. In contrast, pre-procedural Gal-3 appears an independent mortality predictor in high-risk AS patients undergoing BAV.

Galectin-3: a novel biomarker for the prognosis of heart failure

Heart failure (HF) is still a global burden which carries substantial risk of morbidity and mortality. Thus, appropriate approach of diagnosis and layering the prognosis of HF are of great importance. In this paper we discuss and review a novel biomarker, which is called galectin-3 and already approved by Food and Drugs Administration (FDA) as a prediction tool for HF.

Galectin-3, which is secreted by macrophages under the influence of mediators like osteopontin, has been known for its significant role in mediating cardiac fibrosis and inflammation. Numerous studies have shown galectin-3 as a novel prognostic biomarker with high predictive value for cardiovascular mortality and re-hospitalization in HF patients. However, there are also other contradictive studies displayed galectin-3 inferiority against other existed HF prognostic biomarkers like NT-proBNP and ST2. Nevertheless, galectin-3 has some advantages such as more stability and resistance against hemodynamic loading and unloading state, and also it could act as an early indicator of cardiac fibrosis, ventricular remodeling, and renal impairment in HF patients.

Galectin‑3 induces the phenotype transformation of human vascular smooth muscle cells via the canonical Wnt signaling

Galectin‑3, a galactoside‑binding protein, is highly expressed in carotid plaques and plays an important role in the atherosclerotic lesions. The phenotype transformation of vascular smooth muscle cells is the basic pathological change of atherosclerosis. This study investigated the effects of exogenous galectin‑3 on the function and phenotype transformation of human umbilical vascular smooth muscle cells (HUSMC). In this study, we treated vascular smooth muscle cells with recombinant galectin‑3 and tested its effect on cell proliferation, migration, and phenotype transformation. Our results showed that exogenous galectin‑3 promoted human umbilical vascular smooth muscle cells (HUSMC) proliferation and migration. Exogenous galectin‑3 enhanced the expression of the smooth muscle synthetic protein osteopontin, smooth muscle contractile proteins calponin and smooth muscle α‑actin. The galectin‑3‑induced change in cell phenotype was associated with the activation of canonical Wnt signaling, as measured by β‑catenin axin2 and cyclin D1 expression. β‑catenin inhibition by small interfering RNA reduced cell proliferation, decreased cell motility, and blocked galectin‑3‑induced phenotype transformation of human umbilical vascular smooth muscle cells (HUSMC). Our data suggest galectin‑3 promotes the phenotype transformation of human umbilical vascular smooth muscle cells (HUSMC) by activating Wnt/β‑catenin signaling pathway.

Serum Galectin-3 and ST2 as predictors of unfavorable outcome in stable dilated cardiomyopathy patients

Dilated cardiomyopathy (DCM) is the third cause of heart failure and the most frequent cause of heart transplantation (HT). The value of biomarkers in prognostic stratification may be important to identification the patients for more advanced treatment. Assessment of serum Galectin-3 (Gal-3) and ST2 as biomarkers of unfavorable outcome (death and combined endpoint: HT or death or left ventricular assist device implantation) in stable DCM patients. 107 DCM patients age 39-56 years were included into the study and followed-up for mean 4.8 years. Gal-3 and ST2 concentrations were measured ELISA tests. Clinical data, treatment, laboratory parameters, NT-proBNP, Gal-3 and ST2 measured at time of inclusion were assessed as risk factors for reaching the study endpoints using log rank test and Cox proportional-hazards model. During follow-up 27 patients died, 40 achieved combined endpoint. ROC curves indicated cut-off value of ST2-17.53 ng/ml, AUC-0.65 (0.53-0.76) and of NT-proBNP-669 pg/ml, AUC 0.61 (0.50-0.73) for prediction of death. In multivariate analysis ST2 was predictor of death (HR per unit increase in log ST2 2.705, 95 % CI 1.324-5.528, P=0.006) and combined endpoint (HR per unit increase in log ST2 2.753, 95 % CI 1.542-4.914, P<0.001). NT-proBNP was predictive variable only for death in multivariate analysis. Gal-3 concentration was not associated with adverse outcome. ST2 but not Gal-3 may be useful for predicting adverse outcome in stable dilated cardiomyopathy patients.

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

Background—

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

Methods and Results—

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

Conclusions—

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

Galectin-3, osteopontin and successful aging

BACKGROUND

Individuals who reach exceptional longevity (100+ years of age) free of common chronic age diseases (i.e. 'dodgers') arguably represent the paradigm of successful aging in humans. As such, identification of potential biomarkers associated with this phenomenon is of medical interest.

METHODS

We measured serum levels of galectin-3 and osteopontin, both of which have been shown to be linked with major chronic or aging-related disorders in younger populations, in centenarian 'dodgers' (n=81; 40 men; 100-104 years) and healthy controls (n=41; 24 men, 70-80 years).

RESULTS

Both biomarkers showed significantly lower values (p<0.001) in the former (galectin-3: 2.4±1.7 vs. 4.8±2.8 ng/mL; osteopontin: 38.1±27.7 vs. 72.6±33.1 μg/mL). Logistic regression analysis identified the combination of these two biomarkers as a significant predictor variable associated with successful aging regardless of sex (p<0.001). The area under the curve (AUC) classified the ability of galectin-3 and osteopontin to predict the likelihood of successful aging as 'fair' (AUC=0.75) and 'good' (AUC=0.80), respectively. Particularly, the combination of the two biomarkers showed good discriminatory power for successful aging (AUC=0.86), with sensitivity=83% and specificity=74%.

CONCLUSIONS

Lower levels of both galectin-3 and osteopontin are associated with successful aging, representing potential biomarkers of this condition. Our cross-sectional data must be however approached with caution. Further research is necessary to replicate the present preliminary results in other cohorts and to identify the potential use of galectin-3 and osteopontin as potential targets (or at least predictors) in future personalized anti-aging therapies.

Fibrosis and Fibrotic Gene Expression in Pediatric and Adult Patients With Idiopathic Dilated Cardiomyopathy

BACKGROUND

Although fibrosis seems to be prognostic for adverse outcomes in adults with idiopathic dilated cardiomyopathy (IDC), little is known about the prevalence and development of fibrosis in pediatric IDC hearts. We hypothesized that there is less activation of fibrosis at a molecular level in pediatric IDC hearts than in failing adult hearts.

METHODS AND RESULTS

Pediatric hearts were analyzed histologically to determine the prevalence of fibrosis. Left ventricular tissue from adult and pediatric IDC hearts and adult and pediatric nonfailing (NF) hearts were subjected to quantitative reverse-transcription polymerase chain reaction to study the expression of important mRNAs that affect fibrosis. We found age-specific differences between IDC and NF hearts in the regulation of noncoding galectin-3, Corin, matrix metalloproteinase (MMP) 2, MMP-9, tissue inhibitor of metalloproteinase (TIMP) 2, and TIMP-3. We also found markers that were similarly altered in both adult and pediatric IDC hearts (interleukin-1 receptor-like 1 receptor, TIMP-1, and TIMP-4). Finally, microRNAs 29a-c were significantly decreased in the pediatric IDC patients.

CONCLUSIONS

Pediatric IDC patients demonstrate age-specific differences in the molecular pathways implicated in fibrosis in the adult heart. At the ultrastructural level the unique gene expression pattern appears to limit fibrosis in the failing pediatric heart.

Galectin-3 contributes to vascular fibrosis in monocrotaline-induced pulmonary arterial hypertension rat model

Galectin-3 (Gal-3) plays a critical role in vascular inflammation and fibrosis. The role of TGF-β1 in mediating pulmonary vascular fibrosis is well documented; thus, we suspected that Gal-3 could be an important factor in TGF-β1-induced fibrosis in pulmonary adventitial fibroblasts (PAFs). We treated rats with monocrotaline (MCT) and cultured PAFs with TGF-β1 to stimulate fibrosis. We found that MCT injection induced vessel thickening and extracellular matrix deposition in vivo. TGF-β1 stimulated the production of collagen and fibronectin (Fn) protein in vitro. TGF-β1 promoted the expression of Gal-3 and its translocation, while silencing Gal-3 reduced Col-1a deposition. Blockage of STAT3 decreased the expression of Gal-3 induced by TGF-β1. Gal-3 increased Col-1a accumulation and downregulated matrix metallopeptidase 9 (MMP-9) expression in PAFs, but it did not affect Fn expression. These findings demonstrate that Gal-3 is required for TGF-β1-stimulated vascular fibrosis via a STAT3 signaling cascade and that MMP-9 is also involved in TGF-β1/Gal-3-induced vascular fibrosis.

Role for Galectin-3 in Calcific Aortic Valve Stenosis

Background

Aortic stenosis (AS) is a chronic inflammatory disease, and calcification plays an important role in the progression of the disease. Galectin‐3 (Gal‐3) is a proinflammatory molecule involved in vascular osteogenesis in atherosclerosis. Therefore, we hypothesized that Gal‐3 could mediate valve calcification in AS.

Methods and Results

Blood samples and aortic valves (AVs) from 77 patients undergoing AV replacement were analyzed. As controls, noncalcified human AVs were obtained at autopsy (n=11). Gal‐3 was spontaneously expressed in valvular interstitial cells (VICs) from AVs and increased in AS as compared to control AVs. Positive correlations were found between circulating and valvular Gal‐3 levels. Valvular Gal‐3 colocalized with the VICs markers, alpha‐smooth muscle actin and vimentin, and with the osteogenic markers, osteopontin, bone morphogenetic protein 2, runt‐related transcription factor 2, and SRY (sex‐determining region Y)‐box 9. Gal‐3 also colocalized with the inflammatory markers cd68, cd80 and tumor necrosis factor alpha. In vitro, in VICs isolated from AVs, Gal‐3 induced expression of inflammatory, fibrotic, and osteogenic markers through the extracellular signal‐regulated kinase 1 and 2 pathway. Gal‐3 expression was blocked in VICs undergoing osteoblastic differentiation using its pharmacological inhibitor, modified citrus pectin, or the clustered regularly interspaced short palindromic repeats/Cas9 knockout system. Gal‐3 blockade and knockdown decreased the expression of inflammatory, fibrotic, and osteogenic markers in differentiated VICs.

Conclusions

Gal‐3, which is overexpressed in AVs from AS patients, appears to play a central role in calcification in AS. Gal‐3 could be a new therapeutic approach to delay the progression of AV calcification in AS.

GPER is involved in the stimulatory effects of aldosterone in breast cancer cells and breast tumor-derived endothelial cells

Aldosterone induces relevant effects binding to the mineralcorticoid receptor (MR), which acts as a ligand-gated transcription factor. Alternate mechanisms can mediate the action of aldosterone such as the activation of epidermal growth factor receptor (EGFR), MAPK/ERK, transcription factors and ion channels. The G-protein estrogen receptor (GPER) has been involved in the stimulatory effects of estrogenic signalling in breast cancer. GPER has been also shown to contribute to certain responses to aldosterone, however the role played by GPER and the molecular mechanisms implicated remain to be fully understood. Here, we evaluated the involvement of GPER in the stimulatory action exerted by aldosterone in breast cancer cells and breast tumor derived endothelial cells (B-TEC). Competition assays, gene expression and silencing studies, immunoblotting and immunofluorescence experiments, cell proliferation and migration were performed in order to provide novel insights into the role of GPER in the aldosterone-activated signalling. Our results demonstrate that aldosterone triggers the EGFR/ERK transduction pathway in a MR- and GPER-dependent manner. Aldosterone does not bind to GPER, it however induces the direct interaction between MR and GPER as well as between GPER and EGFR. Next, we ascertain that the up-regulation of the Na⁺/H⁺ exchanger-1 (NHE-1) induced by aldosterone involves MR and GPER. Biologically, both MR and GPER contribute to the proliferation and migration of breast and endothelial cancer cells mediated by NHE-1 upon aldosterone exposure. Our data further extend the current knowledge on the molecular mechanisms through which GPER may contribute to the stimulatory action elicited by aldosterone in breast cancer.

Clinical Application of Biomarkers in Heart Failure with a Preserved Ejection Fraction: A Review

Heart failure with a preserved ejection fraction (HFpEF) is increasingly prevalent and a leading cause of morbidity and mortality worldwide. HFpEF has a complex pathophysiology, with recent evidence suggesting that an interaction of cardiovascular and noncardiovascular comorbidities (e.g. obesity, hypertension, diabetes, coronary artery disease, and chronic kidney disease) induces an inflammatory state that eventually leads to myocardial structural and functional alterations. Current ACCF/AHA guidelines suggest incorporation of biomarkers along with clinical and imaging tools to establish the diagnosis and disease severity in heart failure (HF). However, the majority of data on biomarkers relating to their levels, or their role in accurate diagnosis, prognostication, and disease activity, has been derived from studies in undifferentiated HF or HF with a reduced EF (HFrEF). As the understanding of the mechanisms underlying HFpEF continues to evolve, biomarkers reflecting different pathways including neurohormonal activation, myocardial injury, inflammation, and fibrosis have a clinical utility beyond the diagnostic scope. Accordingly, in this review article we describe the various established and novel plasma biomarkers and their emerging value in diagnosis, prognosis, response, and guiding of targeted therapy in patients with HFpEF.

Role of galectin-3 in autoimmune and non-autoimmune nephropathies

Galectins are evolutionary conserved β-galactoside binding proteins with a carbohydrate-recognition domain (CRD) of approximately 130 amino acids. In mammals, 15 members of the galectin family have been identified and classified into three subtypes according to CRD organization: prototype, tandem repeat-type and chimera-type galectins. Galectin-3 (gal-3) is the only chimera type galectin in vertebrates containing one CRD linked to an unusual long N-terminal domain which displays non-lectin dependent activities. Although recent studies revealed unique, pleiotropic and context-dependent functions of gal-3 in both extracellular and intracellular space, gal-3 specific pathways and its ligands have not been clearly defined yet. In the kidney gal-3 is involved in later stages of nephrogenesis as well as in renal cell cancer. However, gal-3 has recently been associated with lupus glomerulonephritis, with Familial Mediterranean Fever-induced proteinuria and renal amyloidosis. Gal-3 has been studied in experimental acute kidney damage and in the subsequent regeneration phase as well as in several models of chronic kidney disease, including nephropathies induced by aging, ischemia, hypertension, diabetes, hyperlipidemia, unilateral ureteral obstruction and chronic allograft injury. Because of the pivotal role of gal-3 in the modulation of immune system, wound repair, fibrosis and tumorigenesis, it is not surprising that gal-3 can be an intriguing prognostic biomarker as well as a promising therapeutic target in a great variety of diseases, including chronic kidney disease, chronic heart failure and cardio-renal syndrome. This review summarizes the functions of gal-3 in kidney pathophysiology focusing on the reported role of gal-3 in autoimmune diseases.

Cardio-renal syndrome

Cardio-renal syndrome is a commonly encountered problem in clinical practice. Its pathogenesis is not fully understood. The purpose of this article is to highlight the interaction between the cardiovascular system and the renal system and how their interaction results in the complex syndrome of cardio-renal dysfunction. Additionally, we outline the available therapeutic strategies to manage this complex syndrome.

MicroRNA-34b/c inhibits aldosterone-induced vascular smooth muscle cell calcification via a SATB2/Runx2 pathway

Increasing evidence shows that aldosterone and specific microRNAs (miRs) contribute to vascular smooth muscle cell (VSMC) calcification. In this study, we aim to explore the mechanistic links between miR-34b/c and aldosterone in VSMC calcification. VSMC calcification models were established both in vitro and in vivo. First, the levels of aldosterone, miR-34b/c and special AT-rich sequence-binding protein 2 (SATB2) were measured. Then, miR-34b/c mimics or inhibitors were transfected into VSMCs to evaluate the function of miR-34b/c. Luciferase reporter assays were used to demonstrate whether SATB2 was a direct target of miR-34b/c. Aldosterone and SATB2 were found to be markedly upregulated during VSMC calcification, whereas miR-34b/c expression was downregulated. Treatment with the mineralocorticoid receptor (MR) antagonist eplerenone inhibited VSMC calcification. In aldosterone-induced VSMC calcification, miR-34b/c levels were downregulated and SATB2 protein was upregulated. Furthermore, miR-34b/c overexpression alleviated aldosterone-induced VSMC calcification as well as inhibited the expression of SATB2 protein, whereas miR-34b/c inhibition markedly enhanced VSMC calcification and upregulated SATB2 protein. In addition, luciferase reporter assays showed that SATB2 is a direct target of miR-34b/c in VSMCs. Overexpression of SATB2 induced Runx2 overproduction and VSMC calcification. Therefore, miR-34b/c participates in aldosterone-induced VSMC calcification via a SATB2/Runx2 pathway. As miR-34b/c appears to be a negative regulator, it has potential as a therapeutic target of VSMC calcification.

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.

Determinants of temporal changes in galectin-3 level in the general population: Data of PREVEND

BACKGROUND

High baseline galectin-3 levels are associated with increased risk for adverse cardiovascular outcomes in the general population, but determinants of changes in galectin-3 levels over time have not been established. Therefore, we aimed to identify determinants of (temporal) change in galectin-3 levels.

METHODS

Galectin-3 plasma levels were measured in a large community based cohort (PREVEND study) at 3 different time points: at baseline, after ~4 and ~9years. The association of baseline clinical and biochemical factors and (temporal) changes in galectin-3 level was assessed using multivariable mixed-effects regression modeling.

RESULTS

In 4355 subjects, galectin-3 plasma levels were available at all time points (mean age: 48±12years; 50% female). Median galectin-3 level at baseline was 10.7 [8.9-12.7] ng/mL which gradually increased to 11.5 [9.4-14.3] ng/mL after ~9years. Using mixed-effects regression modeling, we first validated as independent determinants of baseline circulating galectin-3: eGFR (chi square (χ(2)):210.27, p<0.0001), gender (χ(2):43.85; p<0.0001), BMI (χ(2):19.68, p=0.0001), NT-proBNP (χ(2):18.76, p=0.0001) and serum (total) cholesterol (χ(2):8.63, p=0.01). Furthermore, we identified urinary albumin excretion (χ(2):34.03, p-value: <0.0001) and systolic blood pressure (χ(2):16.81, p=0.002) as independent determinants of temporal changes of galectin-3.

CONCLUSIONS

In the general population, urinary albumin excretion >30mg/24h and systolic blood pressure >170mmHg were identified as significant determinants of dynamic increases in galectin-3 levels over time. These results implicate that treatment of high blood pressure might be effective to prevent increasing galectin-3 levels and its associated conditions.

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).

The Current and Potential Clinical Relevance of Heart Failure Biomarkers

Heart failure is a growing epidemic, and our understanding of the intricacies of its pathophysiology continues to evolve. Over the last decade, biomarkers of heart failure have been extensively investigated, particularly for diagnosis and risk stratification. While the natriuretic peptides remain the gold standard heart failure biomarker, they are plagued by their non-specific nature; furthermore, the strategy of natriuretic peptide-guided care remains elusive. Multiple candidate markers indicative of other physiologic aspects of heart failure have been identified and studied, including soluble ST2, galectin-3, and high-sensitivity cardiac troponins. Each of these biomarkers has the potential to provide unique therapeutically relevant information. Ultimately, a multi-marker approach may be applied to improve care of patients with heart failure. Definitive clinical trials and the use of advanced statistical analytic techniques are needed to truly determine the optimal strategy of biomarker-assisted diagnosis, prognostication, and management of patients who suffer from this devastating condition.

Genetic Variants in the Vicinity of LGALS-3 Gene and LGALS-3 mRNA Expression in Advanced Carotid Atherosclerosis: An Exploratory Study

BACKGROUND

Previous research has shown that there is an association between galectin-3 (gal-3) protein and cardiovascular pathology. The aim of this study was to investigate the effects of rs2274273 and rs17128183 on genetic susceptibility to advanced carotid atherosclerosis (CA) and its complications. The rs2274273 has been singled out as the lead SNP of the haplotype block containing LGALS-3 (gal-3 gene) associated with gal-3 circulating levels, while rs17128183 constitutes a potentially functional SNP of the same hap-block. We further sought to determine whether these genetic variants have an impact on the expression of LGALS-3 mRNA in human carotid atherosclerotic plaque tissue.

METHODS

The study encompassed 300 control subjects and 485 patients with advanced CA who had undergone carotid endarterectomy. Rs2274273, rs17128183, and LGALS-3 relative mRNA expression was detected by means of real-time PCR (TaqMan^® technology).

RESULTS

There were no statistically significant associations of the investigated genetic variants with susceptibility to advanced CA, nor did we find any associations in terms of ultrasonographically defined plaque phenotypes. The relative expression of LGALS-3 mRNA proved to be significantly higher in carriers of the rare alleles (P = 0.039) for both genetic variants.

CONCLUSION

Our exploratory results suggest that while rs2274273 and rs17128183 bear no association with the risk of advanced CA or CA-related complications, these genetic variants are likely to affect LGALS-3 expression levels. In order to reach a definitive conclusion on the role played by rs2274273 and rs17128183 in advanced CA, our results should be further validated.

Galectin-3 and Risk of Heart Failure and Death in Blacks and Whites

Background

The association between galectin‐3 and heart failure (HF) or death is well established for white, but not for black, adults.

Methods and Results

Galectin‐3 was measured in 1809 participants (1375 white, 434 black), enrolled in a substudy of the Atherosclerosis Risk in Communities (ARIC) observational cohort during 2004–2005. We used Cox proportional hazard models to estimate the adjusted association between galectin‐3 and outcomes. Analyses were conducted overall and by race category. Median (interquartile range) galectin‐3 levels were 13.4 (11.2–16.4) and 14.8 (12–17.6) ng/mL, in white and black participants, respectively. In the sample overall, galectin‐3 was not independently associated with HF or death over a maximum of 7.9 years. However, in race‐stratified analyses, galectin‐3 was independently associated with a composite of HF or death among whites (eg, hazard ratio 2.2, 95% CI 1.2–3.9, comparing Q4 versus Q1); but not among blacks (hazard ratio of 0.8 [0.4–1.8] for Q4 versus Q1, race interaction P=0.03). Associations between galectin‐3 and both outcomes analyzed individually also demonstrated similar racial differences. Furthermore, results were qualitatively similar with galectin‐3 modeled as a continuous exposure. In addition, galectin‐3 improved discrimination for the composite of HF or death among whites (increase in Harrell's C statistic from 0.729 to 0.735 [difference of +0.006], P=0.049), but not among blacks (0.696 to 0.695 [difference of −0.001], P=0.814).

Conclusions

In contrast to whites, galectin‐3 may have limited prognostic utility for predicting HF and death in blacks. While our results require replication, they could reflect racial differences in the processes by which galectin‐3 mediates disease.

Galectin-3 and prediction of therapeutic response to renal sympathetic denervation

The profibrotic mediator Galectin-3 (Gal-3) has been associated with aldosterone-mediated vascular inflammation, fibrosis, and stiffness. We evaluated whether the Gal-3 levels and change in Gal-3 as associated with renal denervation can serve as prediction of therapeutic response to renal denervation. A total of 42 patients with resistant hypertension undergoing renal sympathetic denervation (RDN) were included. Blood pressure was evaluated by 24-h ambulatory measurement before RDN and 1, 3 and 6 months after RDN. Treatment response was defined as a drop in systolic ambulatory blood pressure of >5 mm Hg after 6 months. Blood samples were assessed for Gal-3 levels. For the entire group, a significant drop in mean systolic ambulatory blood pressure of 5.2 ± 18.6 mm Hg was observed (p = 0.032). The responder rate was 50% (n = 21). At baseline, Gal-3 levels were significantly higher in responders (14.5 ± 6.0 vs. 10.95 ± 4.6 ng/ml, p = 0.017). There were no significant changes of Gal-3 levels during the follow-up period. The profibrotic biomarker may help to identify patients suitable for RDN.

The Role of Galectin-3 in the Kidneys

Galectin-3 is a 32- to 35-kDa member of the galectin family of b-galactoside-binding lectins, which is characterized by a carbohydrate recognition domain. Through its carbohydrate-binding function, it regulates cell growth, differentiation, and inflammation. It also plays a complex, context-dependent role in the kidneys. During development, it promotes nephrogenesis and is strongly expressed in the ureteric bud and its derivatives. An increase in the concentration of galectin-3 has been reported to be associated with fibrosis of the kidneys. Elevated levels of plasma galectin-3 are also associated with increased risks of rapid renal function decline, incident chronic kidney disease, and progressive renal impairment, and also with cardiovascular end points, infection, and all-cause mortality in patients with renal function impairment. This review discusses a general survey on galectin-3 expressions in nephrogenesis, kidney injury animal models, clinical renal diseases, renal transplantation and the potential role of galectin-3 for treatment in kidney disease.

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

The β-galactoside-binding animal lectin galectin-3 is predominantly expressed by activated macrophages and is a promising biomarker for patients with heart failure. Galectin-3 regulates inflammatory and fibrotic responses; however, its role in cardiac remodeling remains unclear. We hypothesized that galectin-3 may be up-regulated in the pressure-overloaded myocardium and regulate hypertrophy and fibrosis. In normal mouse myocardium, galectin-3 was constitutively expressed in macrophages and was localized in atrial but not ventricular cardiomyocytes. In a mouse model of transverse aortic constriction, galectin-3 expression was markedly up-regulated in the pressure-overloaded myocardium. Early up-regulation of galectin-3 was localized in subpopulations of macrophages and myofibroblasts; however, after 7 to 28 days of transverse aortic constriction, a subset of cardiomyocytes in fibrotic areas contained large amounts of galectin-3. In vitro, cytokine stimulation suppressed galectin-3 synthesis by macrophages and cardiac fibroblasts. Correlation studies revealed that cardiomyocyte- but not macrophage-specific galectin-3 localization was associated with adverse remodeling and dysfunction. Galectin-3 knockout mice exhibited accelerated cardiac hypertrophy after 7 days of pressure overload, whereas female galectin-3 knockouts had delayed dilation after 28 days of transverse aortic constriction. However, galectin-3 loss did not affect survival, systolic and diastolic dysfunction, cardiac fibrosis, and cardiomyocyte hypertrophy in the pressure-overloaded heart. Despite its potential role as a prognostic biomarker, galectin-3 is not a critical modulator of cardiac fibrosis but may delay the hypertrophic response.

Vascular Fibrosis in Aging and Hypertension: Molecular Mechanisms and Clinical Implications

Aging is the primary risk factor underlying hypertension and incident cardiovascular disease. With aging, the vasculature undergoes structural and functional changes characterized by endothelial dysfunction, wall thickening, reduced distensibility, and arterial stiffening. Vascular stiffness results from fibrosis and extracellular matrix (ECM) remodelling, processes that are associated with aging and are amplified by hypertension. Some recently characterized molecular mechanisms underlying these processes include increased expression and activation of matrix metalloproteinases, activation of transforming growth factor-β1/SMAD signalling, upregulation of galectin-3, and activation of proinflammatory and profibrotic signalling pathways. These events can be induced by vasoactive agents, such as angiotensin II, endothelin-1, and aldosterone, which are increased in the vasculature during aging and hypertension. Complex interplay between the “aging process” and prohypertensive factors results in accelerated vascular remodelling and fibrosis and increased arterial stiffness, which is typically observed in hypertension. Because the vascular phenotype in a young hypertensive individual resembles that of an elderly otherwise healthy individual, the notion of “early” or “premature” vascular aging is now often used to describe hypertension-associated vascular disease. We review the vascular phenotype in aging and hypertension, focusing on arterial stiffness and vascular remodelling. We also highlight the clinical implications of these processes and discuss some novel molecular mechanisms of fibrosis and ECM reorganization.

Interaction of Galectin-3 Concentrations with the Treatment Effects of β-Blockers and RAS Blockade in Patients with Systolic Heart Failure: A Derivation-Validation Study from TIME-CHF and GISSI-HF

BACKGROUND

Galectin-3 predicts prognosis in heart failure (HF) and may help to select HF patients in need of intensified therapy.

METHODS

This retrospective post hoc analysis included 219 patients from the Trial of Intensified versus Standard Medical Therapy in Elderly Patients with Congestive Heart Failure (TIME-HF) and 631 patients from Gruppo Italiano per lo Studio della Sopravvivenza nell'Insufficienza Cardiaca (GISSI-HF) with HF who had reduced ejection fraction and available galectin-3 plasma concentrations. The interaction between galectin-3, β-blockers, renin-angiotensin system (RAS) blockade, and spironolactone on outcome was evaluated in TIME-CHF and validated in GISSI-HF. End points were all-cause mortality and the composite of mortality with HF hospitalization or any hospitalization.

RESULTS

High galectin-3 concentrations were associated with adverse outcome in both cohorts and remained significantly associated with death after multivariate adjustment [hazard ratio 2.42 (95% CI 1.17-5.01), P = 0.02, in TIME-CHF; 1.47 (1.02-2.10), P = 0.04, in GISSI-HF). In TIME-CHF, patients with low galectin-3 plasma concentrations had a better prognosis when β-blockers were up-titrated, whereas patients with high galectin-3 plasma concentrations did not (interaction P < 0.05 for mortality and death with or without hospitalization). Opposite trends were seen for RAS blockade but were not statistically significant. Patients with high galectin-3 plasma concentrations had neutral prognosis when receiving spironolactone, whereas patients with low galectin-3 plasma concentrations had worse prognosis when receiving spironolactone (interaction P < 0.10 for death with or without hospitalization). In the GISSI-HF validation cohort, these interactions were confirmed for β-blockers (P < 0.05 for all end points) and consistent for RAS blockade (P < 0.10 for death with or without hospitalization), but inconsistent for spironolactone.

CONCLUSIONS

Galectin-3 is a mediocre prognostic marker, and galectin-3 concentrations interact with the treatment effect of β-blockers and possibly RAS blockade in patients with systolic HF.