Accelerated lipid-induced atherogenesis in galectin-3-deficient mice: role of lipoxidation via receptor-mediated mechanisms

Protective effect of Galectin-3 inhibitor against cardiac remodelling in an isoprenaline-induced myocardial infarction in type 2 diabetes

Type 2 Diabetes mellitus (T2DM) has the potential to impair cardiac function and cause heart failure. We aimed to study the cardioprotective influence of Galactin-3 (Gal-3) inhibitor; modified citrus pectin (MCP) in isoprenaline induced myocardial infarction (MI) in T2DM rats. Forty rats were allocated into 4 groups; groups I and II served as control. T2DM was provoked in groups III and IV by serving them high fat diet followed by a single low dose of Streptozotocin (STZ), then group IV were administered MCP in drinking water for 6 weeks. Groups III and IV were then subcutaneously injected isoprenaline hydrochloride once daily on the last 2 successive days to induce MI. MCP restored echocardiographic parameters with significant decline in Gal-3 area % in cardiac tissue alongside protection against cardiac remodelling. our data showed that there is a protective potential for Gal-3 inhibitor (MCP) against cardiac injury in isoprenaline induced MI in T2DM.

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

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

Single-cell RNA landscape of cell heterogeneity and immune microenvironment in ligation-induced vascular remodeling in rat

BACKGROUND AND AIMS

Vascular remodeling is a common pathological basis for cardiovascular diseases. Although both immune and non-immune cells have been suggested to contribute to this process, the complex cellular heterogeneity and intercellular interactions remain largely uncharacterized.

METHODS AND RESULTS

In this study, we simulated early and late vascular remodeling by ligating the rat carotid artery for 1 week and 4 weeks, respectively. Using single-cell RNA-sequencing, we characterized gene expression signatures and driver signals of major cell types involved in vascular remodeling. Focused analysis revealed a novel sub-population of Selenbp1hi smooth muscle cells (SMCs) associated with vascular remodeling. Results of intercellular communication analyses predicted several ligand-receptor pairs between immune cells with SMCs and endothelial cells (ECs), implicating SMCs apoptosis and repair, ECs aging and inflammatory responses.

CONCLUSIONS

We present a comprehensive single-cell atlas of vascular cells in early and late stages of ligated rat carotid artery, providing valuable insights into the understanding of the initiation and progression of vascular remodeling.

Melatonin inhibits atherosclerosis progression via galectin-3 downregulation to enhance autophagy and inhibit inflammation

Autophagy deficiency in macrophages exacerbates inflammation in atherosclerosis (AS), and recently, galectin-3 (Gal-3) has been implicated as a critical promoter of inflammation in AS. Further, melatonin (Mel) exerts an autophagy-promoting effect in many chronic inflammatory diseases. In this study, we aimed to investigate whether Mel inhibits AS progression by downregulating Gal-3 to enhance autophagy and inhibit inflammation. Thus, we performed in vivo and in vitro experiments using high-fat diet (HFD)-fed ApoE^-/-  mice and THP-1 macrophages, respectively. Smart-seq of AS plaque macrophages revealed that the differentially expressed genes (DEGs) downregulated by Mel were enriched in immune-related processes, and changes in inflammation status were confirmed based on lower levels of proinflammatory factors in Mel-treated HFD-fed ApoE^-/-  mice and THP-1 macrophages. Further, via transcriptome-based multiscale network pharmacology platform (TMNP), the upstream target genes of the smart-seq DEGs were identified, and Gal-3 showed a high score. Gal-3 was downregulated both in vivo and in vitro by Mel treatment. Besides, the enrichment of the target genes predicted via the TMNP method indicated that autophagy considerably affected the DEGs. Mel treatment as well as Gal-3 knockdown downregulated most inflammatory response-related proteins could attribute to enhancing autophagy. Mechanistically, Mel treatment inhibited Gal-3 leading to lowering the activity of the nuclear transcription factor-kappa B (NF-κB) pathway, and promoting the nuclear localization of transcription factor EB (TFEB). However, increased secretion of Gal-3 activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway and impaired autophagy via binding to CD98. Thus, Mel promoted autophagy and restrained inflammation by downregulating Gal-3, implying that it holds promise as a treatment for AS.

Conditioned medium from bone marrow mesenchymal stem cells relieves spinal cord injury through suppression of Gal-3/NLRP3 and M1 microglia/macrophage polarization

The therapeutic effects of bone marrow mesenchymal stem cells (BMSCs) and their conditioned media have been well-documented. This study focused on the effects of BMSC-conditioned medium (BMSCcm) on spinal cord injury (SCI). To study the effects of BMSCcm on rat motor function, inflammatory response, and M1/M2 macrophage/microglial polarization, SCI model rats were treated with BMSCcm and vectors for overexpression of galectin-3 (Gal-3) or NLR family pyrin domain containing 3 (NLRP3). Treatment with BMSCcm reduced the expression of Gal-3 and NLRP3, alleviated the inflammatory response, suppressed M1 microglia/macrophage polarization, and triggered M2 microglia/macrophage polarization in SCI model rats. Meanwhile, overexpression of Gal-3 or NLRP3 counteracted the suppressive effect of BMSCcm on SCI. Moreover, during BMSCcm treatment, overexpression of Gal-3 promoted the expression of NLRP3, whereas overexpression of NLRP3 had no significant effect on the expression of Gal-3. Additionally, the effects of BMSCcm on macrophage/microglial polarization and the underlying molecular mechanisms were observed in vitro. This study demonstrated that BMSCcm alleviates SCI by suppressing the expression of Gal-3 and NLRP3.

Circulating galectin-3 levels are inversely associated with subclinical cardiovascular disease in obese adults

BACKGROUND

Galectin-3 is a new cytokine that is mainly secreted by activated macrophages. It is involved in apoptosis, inflammation and may play a role in the development of cardiovascular disease (CVD). However, there is little information about the association between circulating galectin-3 and subclinical atherosclerosis in humans.

METHODS AND RESULTS

We measured serum galectin-3 in 483 obese adult subjects (aged 40 years and over) who had the measurement of carotid intima-media thickness (CIMT) recruited from the community. Adults with lower levels of circulating galectin-3 had increased CIMT (p < 0.05). In multivariable linear regression analyses, circulating galectin-3 was independently associated with CIMT. The risks of increased CIMT were significantly decreased by 65.1% (OR (95% CI): 0.349 (0.165-0.739)), adjusting for possible confounding factors. Notably, individuals in the lowest quartile of serum galectin-3 were 1.80 times (p < 0.05) more likely to have increased CIMT than those in the highest quartile in multivariable logistic regression analyses; however, such associations with circulating galectin-3 were not noted for carotid plague.

CONCLUSIONS

These findings propose that circulating galectin-3 concentrations are inversely associated with increased CIMT in obese adults, which may be a potential biomarker of CVD.

Red, white, and processed meat consumption related to inflammatory and metabolic biomarkers among overweight and obese women

BACKGROUND

Considering that a high meat intake is directly associated with obesity, it is critical to address the relationship between consuming different types of meat with inflammation and metabolism in overweight and obese cohorts. Thus, we evaluated the association between red, white, and processed meat consumption with inflammatory and metabolic biomarkers in overweight and obese women.

METHODS

The current cross-sectional study was conducted on 391 overweight and obese Iranian women. Dietary intake was obtained from a food frequency questionnaire (FFQ) with 147 items. The anthropometric measurements, serum lipid profile, and inflammatory markers were measured by standard protocols. All associations were assessed utilizing one-way analysis of variance (ANOVA), analysis of covariance (ANCOVA), and linear regression models.

RESULTS

In the adjusted model, it was established that higher intake of processed meat had a significant positive association with leptin levels (β: 0.900, 95% CI: 0.031;1.233, p = 0.015). Moreover, after considering the confounders, a significant positive association between processed meat and macrophage inflammatory protein (MCP-1) levels was observed (β: 0.304, 95% CI:0.100;1.596, p = 0.025). Positive significant associations between high-sensitivity C-reactive protein (hs-CRP) (β:0.020, 95% CI:0.000;0.050, P = 0.014) and plasminogen activator inhibitor 1 (PAI-1) (β:0.263, 95% CI:0.112;0.345, p = 0.053) and MCP-1 (β:0.490, 95% CI: 0.175;1.464, p = 0.071) levels with red meat were also shown; while there was a significant negative association between red meat and the homeostasis model assessment of insulin resistance (HOMA-IR) (β: -0.016, 95% CI: -0.022, -0.001, p = 0.033). Furthermore, a significant negative association were established following confounding adjustment between Galectin-3 (Gal-3) (β: -0.110, 95% CI: -0.271;0.000, p = 0.044), MCP-1 (β: -1.933, 95% CI: -3.721;0.192, p = 0.022) and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (β: -0.011, 95% CI: -0.020,0.000, p = 0.070) levels with high adherence of white meat intake. In contrast, a significant marginally positive association between PAI-1 levels and high adherence to white meat intake (β: -0.340, 95% CI: -0.751;0.050, p = 0.070) has been shown.

CONCLUSIONS

Higher red and processed meat consumption were positively associated with inflammatory and metabolic markers in overweight and obese women. In contrast, negative relationships between high adherence to white meat and various inflammatory and metabolic parameters were established. Further studies are needed to confirm the causality of these associations and potential mediating pathways.

Betaine modulates MIF-mediated oxidative stress, inflammation, and fibrogenesis in Thioacetamide-induced Nephrotoxicity

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine with chemokine properties released by various immune and nonimmune cells. It contributes to the pathogenesis of many inflammatory, autoimmune diseases and malignant tumors.

OBJECTIVE

Our study aimed to investigate the role of betaine in the modulation of MIF-mediated oxidative stress, inflammation, and fibrogenesis during toxic kidney damage induced by thioacetamide (TAA).

METHODS

The experiment is performed on wild-type and knockout MIF-/- C57BL/6 mice. They are randomly divided into groups: Control; Bet-group, received betaine (2% wt/v dissolved in drinking water); MIF-/- mice group; MIF-/-+Bet; TAA-group, treated with TAA (200 mg/kg b.w.), intraperitoneally, 3x/week/8 weeks); TAA+Bet; MIF-/-+TAA, and MIF-/-+TAA+Bet group. After eight weeks of treatment, animals are sacrificed and kidney samples are taken to determine oxidative stress parameters, proinflammatory cytokines, profibrogenic factors, and histopathology of renal tissue Results: In MIF-/-mice, TAA decreases malondialdehyde (MDA) concentration, IL-6, tumor necrosis factor-alpha (TNF-, transforming growth factor-beta 1 (TGF-1) and plateled-derived growth factor-BB (PDGF-BB) and increases superoxide dismutases (SOD) and catalase (CAT) activities, as well as glutathione (GSH) content in kidneys, compared to TAA group. Betaine alleviates the mechanism of MIF-mediated effects in TAA-induced nephrotoxicity, reducing MDA, IL-6, TNF-, TGF-1, and PDGF-BB, and increasing SOD and CAT activity, as well as GSH levels.

CONCLUSION

MIF mediates TAA-induced nephrotoxicity by increasing oxidative stress, inflammation, and profibrogenic mediators. MIF-targeted therapy could potentially alleviate oxidative stress and inflammation in the kidney, as well as pathohistological changes in renal tissue, but the exact mechanism of its action is not completely clear. Betaine alleviates MIF nephrotoxic effects by increasing the antioxidative capacity of kidney cells, and decreasing lipid peroxidation and cytokine production in the renal tissue. It suggests that betaine can be used for the prevention of kidney damage.

Association Between Serum Galectin-3 Levels and Coronary Stenosis Severity in Patients With Coronary Artery Disease

Background

The relationship between galectin-3 (Gal-3) and coronary artery disease (CAD) has not been fully elucidated.

Aim

This study aimed to determine the relationship between the presence and severity of CAD and serum Gal-3 levels.

Patients and Methods

Three-hundred thirty-one consecutive CAD patients were enrolled as the study group. An additional 62 patients without CAD were enrolled as the control group. Serum Gal-3 levels were separately compared between the non-CAD and CAD groups, among the stable CAD and Acute coronary syndrome (ACS) groups, and between CAD patients with low and high SYNTAX scores (SSs). The 1-year cumulative rate of major adverse cardiac events (MACEs) was also compared among ACS patients by Gal-3 levels.

Results

Serum Gal-3 was significantly higher in the CAD group than in the non-CAD group 3.89 (0.16–63.67) vs. 2.07 (0.23–9.38) ng/ml, P < 0.001. Furthermore, serum Gal-3 was significantly higher in the non-ST-segment elevation ACS (NSTE-ACS) group than that in the stable CAD group, 4.72 (1.0–16.14) vs. 2.23 (0.65–23.8) ng/ml, P = 0.04 and higher in the ST-segment elevation myocardial infarction (STEMI) group than that in the stable CAD group 7.87 (0.59–63.67) vs. 2.23 (0.65–23.8) ng/ml, P < 0.001. Serum Gal-3 level was an independent predictor of ACS compared with stable CAD group (OR = 1.131, 95% CI: 1.051–1.217, P = 0.001) as well as high SS (OR = 1.030, 95% CI: 1.021–1.047, P = 0.038) after adjust other confounding risk factors. Acute coronary syndrome patients with Gal-3 levels above the median (gal-3 = 4.78 ng/ml) showed a higher cumulative MACE rate than those with Gal-3 levels below the median. After adjusting other confounding risk factors, Gal-3 remained an independent risk factor for the cumulative rate of MACEs in ACS patients (6% higher rate of MACEs incidence per 1 ng/ml increment of Gal-3).

Conclusion

Galectin-3 correlated with the presence of CAD as well as coronary stability and complexity. Galectin-3 may be valuable in predicting mid-term prognosis in ACS patients.

Predictive Value of Galectin-3 and Brachial-Ankle Pulse Wave Velocity for Coronary Artery Calcification in Coronary Arteriography Patients

OBJECTIVES

To study the predictive value for coronary artery calcification (CAC) of plasma galectin-3 and brachial-ankle pulse wave velocity (BaPWV) in coronary arteriography (CAG) patients.

METHODS

Patients who received coronary arteriography (CAG) examination were recruited. The level of plasma galectin-3 was measured by the enzyme-linked immunosorbent assay. The arterial stiffness was analyzed by BaPWV and ankle-brachial index (ABI) which were measured using a volume-plethysmographic device. Receiver operating characteristic (ROC) curve was used to analyze the prognostic value of galectin-3 or BaPWV for coronary artery calcification (CAC).

RESULTS

The level of galectin-3 and BaPWV was significantly higher in CAC patients compared with that in control (p < 0.01). The level of plasma galectin-3 was positively correlated with BaPWV (r = -0.296, p < 0.01) and negatively correlated with ABI (r = -0.296, p < 0.01). ROC curve analysis revealed that galectin-3 ≥5.90 ng/ml was the most powerful predictor for CAC with sensitivity of 85.5% and specificity of 83.5%. The area under the curve (AUC) was 0.916. When the level of BaPWV was more than 1909 m/s, the sensitivity and specificity were 61.8% and 69.6%, respectively, for predicting CAC. The AUC was 0.646.

CONCLUSIONS

The level of plasma galectin-3 increases significantly in CAC patients compared to control, and its level is related to BaPWV and ABI. Galectin-3 and BaPWV can be used to predict CAC, and the diagnosis value (sensitivity and specificity) of galectin-3 for CAC is better than that of BaPWV.

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

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

Tag Variants of LGALS-3 Containing Haplotype Block in Advanced Carotid Atherosclerosis

OBJECTIVES

Galectin-3 affects a variety of biological processes. It is encoded by LGALS-3, located in unique haplotype block in Caucasians. Most of the studies regarding the gal-3 role in atherosclerosis are focused exclusively on protein/mRNA levels. Genetic analyses of LGALS-3 are scarce. We sought to thoroughly examine the genetic background of gal-3 and to analyze tag variants that cover more than 80% variability of the LGALS-3 containing hap-block in association with carotid plaque presence (CPP). According to Tagger server, rs4040064 G/T, rs11628437 G/A and rs7159490 C/T cover 82% (r² > 0.8) of the genetic variance of this hap-block. Our aims were to investigate possible association of rs4040064, rs11628437 and rs7159490 haplotypes with CPP in patients with advanced carotid atherosclerosis (CA) and to analyze their possible effect on LGALS-3 mRNA expression in carotid plaques.

MATERIALS AND METHODS

Study group consisted of 468 patients and 296 controls. Rs4040064, rs11628437, rs7159490 and LGALS-3 mRNA expression were detected by TaqMan® technology.

RESULTS

We have found that haplotype TAC was associated with the cerebrovascular insult (CVI) occurrence (OR = 1.68, 95% CI = 1.09-2.58, p = 0.02), compared to the referent haplotype. OR was adjusted for hypertension, age and BMI. TAC also showed higher, but not statistically significant, LGALS-3 expression in carotid plaques.

CONCLUSIONS

Our results suggest that rs4040064, rs11628437 and rs7159490 bear no association with CPP, neither they affect LGALS-3 mRNA in carotid plaques. However, we showed a significant association of haplotype TAC with the CVI occurrence in CA patients from Serbia. Replication and validation of our results are required.

Associations of galectin-3 expression and LGALS-3 (rs4652) gene variant with coronary artery disease risk in diabetics

Background

Galectin-3 protein encoded by lectin galactoside-binding soluble-3 (LGALS-3) gene is an important genetic factor in type 2 diabetes mellitus (T2DM) and its cardiovascular obstacles in various populations. We aimed to elicit the pro-inflammatory effect of galectin-3 as determined by interleukin-6 (IL-6) serum levels and to explore the relationship between galectin-3 (LGALS-3 rs4652) gene variant and its expression levels with coronary artery disease (CAD) risk among T2DM Egyptian patients.

Methods

112 lean subjects were compared to 100 T2DM without CAD and 84 T2DM with CAD. A tetra-primer amplification refractory mutation system polymerase chain reaction was used to test LGALS-3 (rs4652), and galectin3 expression was tested with a quantitative real-time polymerase chain reaction. Serum IL-6 was measured using an enzyme-linked immunosorbent assay.

Results

We found that the prevalence of LGALS-3 (rs4652) AC genotype and galectin-3 gene expression levels in T2DM with CAD were significantly higher than the additional 2 groups and were correlated positively to IL-6 circulating levels. Also, the C allele carriers (AC+CC) had significantly higher relative Galectin-3 expression levels compared to the A allele carriers (AA).

Conclusions

We concluded that galectin-3 expression levels and LGALS-3 (rs4652) AC genotype were coronary artery disease risk factors in people with type two diabetes among an Egyptian sample.

Interaction between Galectin-3 and Integrins Mediates Cell-Matrix Adhesion in Endothelial Cells and Mesenchymal Stem Cells

Galectin-3 (Gal-3) is a β-galactoside-binding protein that influences various cell functions, including cell adhesion. We focused on the role of Gal-3 as an extracellular ligand mediating cell-matrix adhesion. We used human adipose tissue-derived stem cells and human umbilical vein endothelial cells that are promising for vascular tissue engineering. We found that these cells naturally contained Gal-3 on their surface and inside the cells. Moreover, they were able to associate with exogenous Gal-3 added to the culture medium. This association was reduced with a β-galactoside LacdiNAc (GalNAcβ1,4GlcNAc), a selective ligand of Gal-3, which binds to the carbohydrate recognition domain (CRD) in the Gal-3 molecule. This ligand was also able to detach Gal-3 newly associated with cells but not Gal-3 naturally present on cells. In addition, Gal-3 preadsorbed on plastic surfaces acted as an adhesion ligand for both cell types, and the cell adhesion was resistant to blocking with LacdiNAc. This result suggests that the adhesion was mediated by a binding site different from the CRD. The blocking of integrin adhesion receptors on cells with specific antibodies revealed that the cell adhesion to the preadsorbed Gal-3 was mediated, at least partially, by β1 and αV integrins-namely α5β1, αVβ3, and αVβ1 integrins.

Galectin-3 in Cardiovascular Diseases

Galectin-3 (Gal-3) is a β-galactoside-binding protein belonging to the lectin family with pleiotropic regulatory activities and several physiological cellular functions, such as cellular growth, proliferation, apoptosis, differentiation, cellular adhesion, and tissue repair. Inflammation, tissue fibrosis and angiogenesis are the main processes in which Gal-3 is involved. It is implicated in the pathogenesis of several diseases, including organ fibrosis, chronic inflammation, cancer, atherosclerosis and other cardiovascular diseases (CVDs). This review aims to explore the connections of Gal-3 with cardiovascular diseases since they represent a major cause of morbidity and mortality. We herein discuss the evidence on the pro-inflammatory role of Gal-3 in the atherogenic process as well as the association with plaque features linked to lesion stability. We report the biological role and molecular mechanisms of Gal-3 in other CVDs, highlighting its involvement in the development of cardiac fibrosis and impaired myocardium remodelling, resulting in heart failure and atrial fibrillation. The role of Gal-3 as a prognostic marker of heart failure is described together with possible diagnostic applications to other CVDs. Finally, we report the tentative use of Gal-3 inhibition as a therapeutic approach to prevent cardiac inflammation and fibrosis.

The roles of galectins in hepatic diseases

Hepatic diseases include all diseases that occur in the liver, including hepatitis, cirrhosis, hepatocellular carcinoma, etc. Hepatic diseases worldwide are characterized by high incidences of digestive system diseases, which present with subtle symptoms, are difficult to treat and have high mortality. Galectins are β-galactoside-binding proteins that have been found to be aberrantly expressed during hepatic disease progression. An increasing number of studies have shown that abnormal expression of galectins is extensively involved in hepatic diseases, such as hepatocellular carcinoma (HCC), liver cirrhosis, hepatitis and liver fibrosis. Galectins function as intracellular and extracellular hepatic disease regulators mainly through the binding of their carbohydrate recognition domain to glycoconjugates expressed in hepatocytes. In this review, we summarize current research on the various roles of galectins in cirrhosis, hepatitis, liver fibrosis and HCC, which may provide a preliminary theoretical basis for the exploration of new targets for the treatment of hepatic diseases.

Galectin-3 inhibition attenuates doxorubicin-induced cardiac dysfunction by upregulating the expression of peroxiredoxin-4

Doxorubicin (DOX) is a highly efficient chemotherapeutic drug limited by its cardiotoxicity. Galectin-3 (Gal-3) overexpression is associated with several cardiovascular diseases. In this study, the in vivo models of DOX-treated rats and the in vitro model of DOX-treated H9C2 cells were used. DOX induced cardiac injury and dysfunction accompanied with the upregulation of Gal-3 at the end of the experiment, while inhibition of Gal-3 with modified citrus pectin (MCP) exhibited a dramatic improvement in cardiac function of the DOX-treated rats, as manifested by increased left ventricular systolic pressure and ±dp/dt_max and decreased left ventricular end-diastolic pressure. The plasma levels of myocardial injury markers such as lactate dehydrogenase, creatine kinase, creatine kinase-MB, and cardiac troponin I were decreased after MCP treatment. In parallel, MCP attenuated myocardial tissue markers of oxidative stress such as hydrogen peroxide and malondialdehyde restored the activities of superoxide dismutase, catalase, and glutathione peroxidase and upregulated antioxidant peroxiredoxin-4 (Prx-4). To further verify the role of Prx-4, it was downregulated by siRNA-mediated knockdown in H9C2 cells. MCP could not reverse DOX-induced oxidative stress in Prx-4-knock-down cells. In conclusion, Gal-3 mediated DOX-induced cardiotoxicity and Gal-3 inhibition attenuated DOX-induced cardiac dysfunction by upregulating the expression of Prx-4 to reduce myocardial oxidative stress.

Galectin-3 Identifies a Subset of Macrophages With a Potential Beneficial Role in Atherosclerosis

OBJECTIVE

Galectin-3 (formerly known as Mac-2), encoded by the LGALS3 gene, is proposed to regulate macrophage adhesion, chemotaxis, and apoptosis. We investigated the role of galectin-3 in determining the inflammatory profile of macrophages and composition of atherosclerotic plaques. Approach and Results: We observed increased accumulation of galectin-3-negative macrophages within advanced human, rabbit, and mouse plaques compared with early lesions. Interestingly, statin treatment reduced galectin-3-negative macrophage accrual in advanced plaques within hypercholesterolemic (apolipoprotein E deficient) Apoe-/- mice. Accordingly, compared with Lgals3+/+:Apoe-/- mice, Lgals3-/-:Apoe-/- mice displayed altered plaque composition through increased macrophage:smooth muscle cell ratio, reduced collagen content, and increased necrotic core area, characteristics of advanced plaques in humans. Additionally, macrophages from Lgals3-/- mice exhibited increased invasive capacity in vitro and in vivo. Furthermore, loss of galectin-3 in vitro and in vivo was associated with increased expression of proinflammatory genes including MMP (matrix metalloproteinase)-12, CCL2 (chemokine [C-C motif] ligand 2), PTGS2 (prostaglandin-endoperoxide synthase 2), and IL (interleukin)-6, alongside reduced TGF (transforming growth factor)-β1 expression and consequent SMAD signaling. Moreover, we found that MMP12 cleaves macrophage cell-surface galectin-3 resulting in the appearance of a 22-kDa fragment, whereas plasma levels of galectin-3 were reduced in Mmp12-/-:Apoe-/- mice, highlighting a novel mechanism where MMP12-dependent cleavage of galectin-3 promotes proinflammatory macrophage polarization. Moreover, galectin-3-positive macrophages were more abundant within plaques of Mmp12-/-:Apoe-/- mice compared with Mmp12+/+:Apoe-/- animals.

CONCLUSIONS

This study reveals a prominent protective role for galectin-3 in regulating macrophage polarization and invasive capacity and, therefore, delaying plaque progression.

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

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

Galectin-3 is associated with severe heart failure and death: A hospital-based study in Chinese patients

Heart failure (HF) is a serious disease syndrome characterized by elevated pro-inflammatory cytokines and inflammatory mediators presume to have significant contribution on disease progression. Galectins are carbohydrate-binding proteins responsible of various physiological functions. Role of galectins in heart failure has been ill-defined. In the present case-controls study, 136 patients clinically diagnosed with heart failure and 125 healthy Chinese controls were recruited. Levels of galectins (Gal-1, 3 and 9) and cytokines (IFN-γ, IL-17A, IL-4 and TGF-β) were quantified by ELISA. Increased levels of galectin-1 and 3 was observed in HF patients and associated with clinical severity. In addition, pro-inflammatory cytokines such as IFN-γ and IL-17A were increased in patients whereas, anti-inflammatory TGFβ was decreased. Galectin-3 was positively correlated with IFN-γ, IL-17A and inversely with TGF-β. Furthermore, ROC curve analysis suggested galectin-3 as a promising biomarker for diagnosis and HF and clinical severity. Interestingly, a two-year follow-up indicated significant association of elevated galectin-3 with mortality due to HF. In conclusion, galectin-3 associated with HF and clinical manifestations possibly by inducing pro-inflammatory cytokines and could be a possible biomarker of HF and severe clinical conditions.

Galectin-3 Is a Potential Mediator for Atherosclerosis

Atherosclerosis is a multifactorial chronic inflammatory arterial disease forming the pathological basis of many cardiovascular diseases such as coronary heart disease, heart failure, and stroke. Numerous studies have implicated inflammation as a key player in the initiation and progression of atherosclerosis. Galectin-3 (Gal-3) is a 30 kDa β-galactose, highly conserved and widely distributed intracellularly and extracellularly. Gal-3 has been demonstrated in recent years to be a novel inflammatory factor participating in the process of intravascular inflammation, lipid endocytosis, macrophage activation, cellular proliferation, monocyte chemotaxis, and cell adhesion. This review focuses on the role of Gal-3 in atherosclerosis and the mechanism involved and several classical Gal-3 agonists and antagonists in the current studies.

The Role of Myeloid-Derived Cells in the Progression of Liver Disease

Control of homeostasis and rapid response to tissue damage in the liver is orchestrated by crosstalk between resident and infiltrating inflammatory cells. A crucial role for myeloid cells during hepatic injury and repair has emerged where resident Kupffer cells, circulating monocytes, macrophages, dendritic cells and neutrophils control local tissue inflammation and regenerative function to maintain tissue architecture. Studies in humans and rodents have revealed a heterogeneous population of myeloid cells that respond to the local environment by either promoting regeneration or driving the inflammatory processes that can lead to hepatitis, fibrogenesis, and the development of cirrhosis and malignancy. Such plasticity of myeloid cell responses presents unique challenges for therapeutic intervention strategies and a greater understanding of the underlying mechanisms is needed. Here we review the role of myeloid cells in the establishment and progression of liver disease and highlight key pathways that have become the focus for current and future therapeutic strategies.

Galectin-3 and risk of cardiovascular events and all-cause mortality in type 2 diabetes

AIMS

Recent clinical studies have shown that galectin-3 is a prognostic indicator in patients with coronary heart disease and in patients with heart failure. Experimental data suggest that galectin-3 may play a role in atherogenesis. We have evaluated whether serum galectin-3 level is associated with cardiovascular outcome in type 2 diabetes.

MATERIALS AND METHODS

Galectin-3 was measured in baseline samples in 1495 persons with type 2 diabetes. The primary cardiovascular outcome, incident cardiovascular events, was defined as first non-fatal myocardial infarction, non-fatal stroke, coronary revascularization, or death from cardiovascular cause. The secondary outcome was all-cause mortality.

RESULTS

At baseline, 12% of the subjects had prevalent cardiovascular disease. Serum galectin-3 was increased in the group with incident cardiovascular events compared with those who remained free of events during follow up (9.03 ± 2.98 ng/mL vs 8.15 ± 2.76, P < 0.01). Serum galectin-3 was also significantly increased in those subjects with a fatal outcome. The hazard ratios (HR) for cardiovascular events and all-cause mortality for individuals in the top quartile were 2.50 (95% CI 1.87, 3.36, P < 0.001) and 3.92 (95%CI 2.55, 6.01, P < 0.001), respectively. In a multivariate Cox regression analysis including traditional risk factors, log (eGFR), baseline albuminuria, and cardiovascular disease status, the HR per standard deviation change in galectin-3 was 1.13 (95% CI 1.02, 1.26, P = 0.02) for cardiovascular events and 1.17 (95% CI 1.01, 1.35, P = 0.04) for all-cause mortality.

CONCLUSIONS

Serum galectin-3 is associated with adverse cardiovascular outcomes in persons with type 2 diabetes independent of traditional risk factors.

Plasma Galectin-3 and Sonographic Measures of Carotid Atherosclerosis in the Atherosclerosis Risk in Communities Study

Galectin-3 is a β-galactoside-binding lectin that plays a role in the regulation of several conditions that are associated with atherosclerosis. The goal of this cross-sectional study was to assess the association of plasma galectin-3 concentrations with sonographic measures of carotid atherosclerosis in the Atherosclerosis Risk in Communities study. Linear regression was used to determine the difference and 95% confidence intervals (CIs) for carotid intima-media thickness (cIMT) by categorical and continuous representations of galectin-3. Logistic regression was used to determine the odds ratio and 95% CI, separately, for dichotomized cIMT (75th percentile = 0.9 mm) and carotid plaque and/or shadowing. Compared to those in the first quintile of galectin-3, those in the fifth quintile of galectin-3 level had higher cIMT (mean difference: 0.020 mm after multivariable adjustment; P trend = .04). Moreover, compared to those in the lowest galectin-3 quintile, those in the highest galectin-3 quintile had higher odds of carotid plaque/and or shadowing (odds ratio 1.13 after multivariable adjustment; P trend = .014). Higher levels of galectin-3 are associated with greater carotid atherosclerosis. Our findings provide support for the role of inflammatory biomarkers in the pathogenesis of atherosclerosis and suggest galectin-3 as a possible target for intervention in the prevention or management of atherosclerotic disease.

Galectin-3 is essential for proper bone cell differentiation and activity, bone remodeling and biomechanical competence in mice

OBJECTIVE

Galectin-3 is constitutively expressed in bone cells and was recently shown to modulate osteogenic transdifferentiation of vascular smooth muscle cells and atherosclerotic calcification. However, the role of galectin-3 in bone physiology is largely undefined. To address this issue, we analyzed (1) the skeletal features of 1-, 3- and 6-month-old galectin-3 null (Lgals3^-/-) and wild type (WT) mice and (2) the differentiation and function of osteoblasts and osteoclasts derived from these animals.

METHODS

Long bone phenotype, gene expression profile, and remodeling were investigated by micro-computed tomography, real time-PCR, static and dynamic histomorphometry, and assessment of biochemical markers of bone resorption and formation. Bone competence was also evaluated by biomechanical testing at 3 months. In vitro, the effects of galectin-3 deficiency on bone cell differentiation and function were investigated by assessing (a) gene expression of osteoblast markers, alkaline phosphatase activity, mineralization assay, and WNT/β-catenin signaling (of which galectin-3 is a known regulator) in osteoblasts; and (b) tartrate-resistant acid phosphatase activity and bone resorption activity in osteoclasts.

RESULTS

Lgals3^-/- mice revealed a wide range of age-dependent alterations including lower bone formation and higher bone resorption, accelerated age-dependent trabecular bone loss (p < 0.01 vs. WT at 3 months) and reduced bone strength (p < 0.01 vs. WT at 3 months). These abnormalities were accompanied by a steady inflammatory state, as revealed by higher bone expression of the pro-inflammatory cytokines interleukin (IL)-1β and IL-6 (p < 0.001 vs. WT at 3 months), increased content of osteal macrophages (p < 0.01 vs. WT at 3 months), and reduced expression of markers of alternative (M2) macrophage activation. Lgals3^-/- osteoblasts and osteoclasts showed impaired terminal differentiation, reduced mineralization capacity (p < 0.01 vs. WT cells) and resorption activity (p < 0.01 vs. WT cells). Mechanistically, impaired differentiation and function of Lgals3^-/- osteoblasts was associated with altered WNT/β-catenin signaling (p < 0.01 vs. WT cells).

CONCLUSIONS

These data provide evidence for a contribution of galectin-3 to bone cell maturation and function, bone remodeling, and biomechanical competence, thus identifying galectin-3 as a promising therapeutic target for age-related disorders of bone remodeling.

The advanced glycation end-product Nϵ -carboxymethyllysine promotes progression of pancreatic cancer: implications for diabetes-associated risk and its prevention

Diabetes is an established risk factor for pancreatic cancer (PaC), together with obesity, a Western diet, and tobacco smoking. The common mechanistic link might be the accumulation of advanced glycation end-products (AGEs), which characterizes all of the above disease conditions and unhealthy habits. Surprisingly, however, the role of AGEs in PaC has not been examined yet, despite the evidence of a tumour-promoting role of receptor for advanced glycation end-products (RAGE), the receptor for AGEs. Here, we tested the hypothesis that AGEs promote PaC through RAGE activation. To this end, we investigated the effects of the AGE N^ϵ -carboxymethyllysine (CML) in human pancreatic ductal adenocarcinoma (PDA) cell lines and in a mouse model of Kras-driven PaC interbred with a bioluminescent model of proliferation. Tumour growth was monitored in vivo by bioluminescence imaging and confirmed by histology. CML promoted PDA cell growth and RAGE expression, in a concentration-dependent and time-dependent manner, and activated downstream tumourigenic signalling pathways. These effects were counteracted by RAGE antagonist peptide (RAP). Exogenous AGE administration to PaC-prone mice induced RAGE upregulation in pancreatic intraepithelial neoplasias (PanINs) and markedly accelerated progression to invasive PaC. At 11 weeks of age (6 weeks of CML treatment), PaC was observed in eight of 11 (72.7%) CML-treated versus one of 11 (9.1%) vehicle-treated [control (Ctr)] mice. RAP delayed PanIN development in Ctr mice but failed to prevent PaC promotion in CML-treated mice, probably because of competition with soluble RAGE for binding to AGEs and/or compensatory upregulation of the RAGE homologue CD166/ activated leukocyte cell adhesion molecule, which also favoured tumour spread. These findings indicate that AGEs modulate the development and progression of PaC through receptor-mediated mechanisms, and might be responsible for the additional risk conferred by diabetes and other conditions characterized by increased AGE accumulation. Finally, our data suggest that an AGE reduction strategy, instead of RAGE inhibition, might be suitable for the risk management and prevention of PaC. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

FL-926-16, a novel bioavailable carnosinase-resistant carnosine derivative, prevents onset and stops progression of diabetic nephropathy in db/db mice

BACKGROUND AND PURPOSE

The advanced glycation end products (AGEs) participate in the pathogenesis of diabetic nephropathy (DN) by promoting renal inflammation and injury. L-carnosine acts as a quencher of the AGE precursors reactive carbonyl species (RCS), but is rapidly inactivated by carnosinase. In this study, we evaluated the effect of FL-926-16, a carnosinase-resistant and bioavailable carnosine derivative, on the onset and progression of DN in db/db mice.

EXPERIMENTAL APPROACH

Adult male db/db mice and coeval db/m controls were left untreated or treated with FL-926-16 (30 mg·kg^-1 body weight) from weeks 6 to 20 (prevention protocol) or from weeks 20 to 34 (regression protocol).

KEY RESULTS

In the prevention protocol, FL-926-16 significantly attenuated increases in creatinine (-80%), albuminuria (-77%), proteinuria (-75%), mean glomerular area (-34%), fractional (-40%) and mean (-42%) mesangial area in db/db mice. This protective effect was associated with a reduction in glomerular matrix protein expression and cell apoptosis, circulating and tissue oxidative and carbonyl stress, and renal inflammatory markers, including the NLRP3 inflammasome. In the regression protocol, the progression of DN was completely blocked, although not reversed, by FL-926-16. In cultured mesangial cells, FL-926-16 prevented NLRP3 expression induced by RCS but not by the AGE N^ε -carboxymethyllysine.

CONCLUSION AND IMPLICATIONS

FL-926-16 is effective at preventing the onset of DN and halting its progression in db/db mice by quenching RCS, thereby reducing the accumulation of their protein adducts and the consequent inflammatory response. In a future perspective, this novel compound may represent a promising AGE-reducing approach for DN therapy.

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.

Hematopoietic-Derived Galectin-3 Causes Cellular and Systemic Insulin Resistance

In obesity, macrophages and other immune cells accumulate in insulin target tissues, promoting a chronic inflammatory state and insulin resistance. Galectin-3 (Gal3), a lectin mainly secreted by macrophages, is elevated in both obese subjects and mice. Administration of Gal3 to mice causes insulin resistance and glucose intolerance, whereas inhibition of Gal3, through either genetic or pharmacologic loss of function, improved insulin sensitivity in obese mice. In vitro treatment with Gal3 directly enhanced macrophage chemotaxis, reduced insulin-stimulated glucose uptake in myocytes and 3T3-L1 adipocytes and impaired insulin-mediated suppression of glucose output in primary mouse hepatocytes. Importantly, we found that Gal3 can bind directly to the insulin receptor (IR) and inhibit downstream IR signaling. These observations elucidate a novel role for Gal3 in hepatocyte, adipocyte, and myocyte insulin resistance, suggesting that Gal3 can link inflammation to decreased insulin sensitivity. Inhibition of Gal3 could be a new approach to treat insulin resistance.

Serum levels of galectin-1, galectin-3, and galectin-9 are associated with large artery atherosclerotic stroke

The aim of this study was to assess the expression patterns of serum galectin-1 (Gal-1), galectin-3 (Gal-3), galectin-9 (Gal-9), and galectin-3 binding protein (Gal-3BP) and their associations with stroke outcome in large artery atherosclerotic (LAA) stroke. The serum levels of Gal-1, Gal-3, Gal-9, and Gal-3BP were measured by ELISA in 130 patients with LAA stroke and 130 age- and sex-matched controls. Serum samples were collected from the patients on day 1, day 6, and in the 4th week after ischaemic stroke (IS). An unfavourable outcome was defined as a modified Rankin Scale score of >2 on day 90 after IS. Our results indicated that the Gal-3 and Gal-9 levels were higher in patients with LAA stroke than in controls. A higher Gal-3 level was independently associated with an unfavourable outcome both on day 1 and day 6 after IS. In addition, Gal-9 and Gal-1 levels were upregulated on day 6 and in the 4th week after IS, respectively. For Gal-3BP, no difference was detected between patients and controls and no predictive value was found in patients. In conclusion, these findings suggest that the serum levels of Gal-1, Gal-3, and Gal-9 may be associated with LAA stroke.

Relationship of galectin-3 with obesity, IL-6, and CRP in women

PURPOSE

To evaluate the association of galectin-3 (Gal3) with obesity and inflammatory status in a cohort of metabolically healthy, predominantly African-American women with varying cardiovascular disease (CVD) risk as determined by CRP levels.

METHODS

We assessed the association between BMI and serum levels of Gal3, IL-6, CRP, and adiponectin in metabolically healthy women (N = 97) to determine the overall association between Gal3, obesity, and inflammation in groups at different CVD risk.

RESULTS

Obese women had significantly higher serum Gal3 compared to non-obese participants (P = 0.0016), although Gal3 levels were comparable among different classes of obesity. BMI (R ² = 0.1406, P = 0.0013), IL-6 (R ² = 0.0689, P = 0.035), and CRP (R ² = 0.0468, P = 0.0419), but not adiponectin, positively predicted the variance of Gal3 levels in the total study population. However, the predicting effect of BMI (R ² = 0.2923, P = 0.0125) and inflammation (R ² = 0.3138, P = 0.038) on Gal3 was only present in women at low/moderate risk of CVD (CRP ≤ 3 µg/mL).

CONCLUSIONS

Gal3 is positively correlated with obesity and inflammation in women, while the presence of elevated CVD risk may disturb the strength of Gal3 as a biomarker of inflammation.

Galectin-3 and IL-33/ST2 axis roles and interplay in diet-induced steatohepatitis

Immune reactivity and chronic low-grade inflammation (metaflammation) play an important role in the pathogenesis of obesity-associated metabolic disorders, including type 2 diabetes and nonalcoholic fatty liver disease (NAFLD), a spectrum of diseases that include liver steatosis, nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Increased adiposity and insulin resistance contribute to the progression from hepatic steatosis to NASH and fibrosis through the development of proinflammatory and profibrotic processes in the liver, including increased hepatic infiltration of innate and adaptive immune cells, altered balance of cytokines and chemokines, increased reactive oxygen species generation and hepatocellular death. Experimental models of dietary-induced NAFLD/NASH in mice on different genetic backgrounds or knockout mice with different immune reactivity are used for elucidating the pathogenesis of NASH and liver fibrosis. Galectin-3 (Gal-3), a unique chimera-type β-galactoside-binding protein of the galectin family has a regulatory role in immunometabolism and fibrogenesis. Mice deficient in Gal-3 develop pronounced adiposity, hyperglycemia and hepatic steatosis, as well as attenuated liver inflammation and fibrosis when fed an obesogenic high-fat diet. Interleukin (IL)-33, a member of the IL-1 cytokine family, mediates its effects through the ST receptor, which is present on immune and nonimmune cells and participates in immunometabolic and fibrotic disorders. Recent evidence, including our own data, suggests a protective role for the IL-33/IL-33R (ST2) signaling pathway in obesity, adipose tissue inflammation and atherosclerosis, but a profibrotic role in NASH development. The link between Gal-3 and soluble ST2 in myocardial fibrosis and heart failure progression has been demonstrated and we have recently shown that Gal-3 and the IL-33/ST2 pathway interact and both have a profibrotic role in diet-induced NASH. This review discusses the current evidence on the roles of Gal-3 and the IL-33/ST2 pathway and their interplay in obesity-associated hepatic inflammation and fibrogenesis that may be of interest in the development of therapeutic interventions to prevent and/or reverse obesity-associated hepatic inflammation and fibrosis.

Soluble galectin-3 is associated with premature myocardial infarction

BACKGROUND

Inflammatory responses are pivotal in the initiation and development of premature atherosclerotic lesions. Galectin-3 represents a valuable biomarker for both progression and destabilization of atherosclerotic lesions. This study aims to assess the involvement of galectin-3 in premature myocardial infarction.

DESIGN

In this multicentre case-control study, we assessed circulating galectin-3 levels in 144 patients comprising 72 consecutive survivors of acute myocardial infarction (≤ 40 years) and 72 hospital controls frequency matched for age, gender and centre.

RESULTS

Patients with acute myocardial infarction showed significantly higher galectin-3 levels as compared to controls in the acute phase of acute myocardial infarction (2552 ± 1992 vs. 1666 ± 829 pg/mL; P < 0·001) as well as in the stable phase 1 year after the index event (3692 ± 1774 vs. 1666 ± 829 pg/mL; P < 0·001). Circulating galectin-3 was significantly and independently associated with premature myocardial infarction in the logistic regression analysis (acute phase: adj. OR per 1-SD change 2·03, 95% CI 1·30-3·19; P = 0·002; stable phase: adj. OR of 6·54 (95% CI 2·56-16·68; P < 0·001). Moreover, we observed a significant correlation between circulating galectin-3 and leucocyte count (r = 0·35, P < 0·001), non-HDL cholesterol (r = 0·23, P = 0·014) and HDL cholesterol (r = -0·29, P = 0·002).

CONCLUSION

We demonstrated that elevated levels of circulating galectin-3 are strongly associated with premature myocardial infarction. Galectin-3 might serve as link between dyslipidaemia as driving force of plaque formation with inflammation as initiator of plaque rupture in patients with premature acute myocardial infarction.

Association between serum galectin-3 levels and coronary atherosclerosis and plaque burden/structure in patients with type 2 diabetes mellitus

BACKGROUND

Levels of galectin-3, a member of a family of soluble β-galactoside-binding lectins, are reported to be higher in patients with type 2 diabetes mellitus (DM) and metabolic syndrome. Conflicting results exist on the effects of galectin-3 in diabetic patients. The aim of this study was to investigate the relationship between galectin-3 levels and coronary artery disease (CAD), coronary plaque burden, and plaque structures in patients with type 2 DM.

PATIENTS AND METHODS

A total of 158 consecutive patients with type 2 DM undergoing planned coronary computed tomography angiography (CCTA) were included in this study. The study population was divided into CAD and non-CAD groups according to the presence of CCTA-determined coronary atherosclerosis.

RESULTS

Galectin-3 concentrations were significantly higher in the CAD group than in the non-CAD group (1412.0 ± 441.7 vs. 830.2 ± 434.9 pg/ml, P < 0.001). Galectin-3 levels were correlated positively with BMI, high-sensitivity C-reactive protein, the total number of diseased vessels, the number of plaques (all, P < 0.001), and the calcified plaque type (P = 0.001). In addition, galectin-3 levels were found to be a significant independent predictor of coronary atherosclerosis in type 2 diabetic patients (P = 021; odds ratio, 1.002; 95% confidence interval, 1.000-1.003).

CONCLUSION

Galectin-3 is a novel, promising biomarker that may help identify type 2 diabetic patients who may require early CAD intervention because of the potential risk of coronary atherosclerosis.

Non-alcoholic steatohepatitis: emerging molecular targets and therapeutic strategies

Non-alcoholic fatty liver disease - the most common chronic liver disease - encompasses a histological spectrum ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). Over the next decade, NASH is projected to be the most common indication for liver transplantation. The absence of an effective pharmacological therapy for NASH is a major incentive for research into novel therapeutic approaches for this condition. The current focus areas for research include the modulation of nuclear transcription factors; agents that target lipotoxicity and oxidative stress; and the modulation of cellular energy homeostasis, metabolism and the inflammatory response. Strategies to enhance resolution of inflammation and fibrosis also show promise to reverse the advanced stages of liver disease.

Circulating Galectin-3 Is Associated With Cardiometabolic Disease in the Community

BACKGROUND

Circulating Galectin-3 (Gal-3) concentrations are associated with an increased incidence of heart failure, atrial fibrillation, chronic kidney disease, and mortality. Recent evidence suggests that Gal-3 may also be an important modulator of cardiometabolic traits such as adiposity, insulin resistance, and hyperglycemia. We examined the associations of blood Gal-3 concentrations and cardiometabolic disease traits in the Framingham Heart Study.

METHODS AND RESULTS

In cross-sectional analyses of 2946 Framingham Heart Study participants (mean age 59 years, 55% women), higher Gal-3 concentrations were associated with higher body mass index, waist circumference, and triglycerides (P<0.0001 for all). Higher Gal-3 was associated with greater odds of obesity (multivariable-adjusted odds ratio 1.16 per 1-SD increase in log-Gal-3, 95% CI 1.06-1.28, P=0.002) and hypertension (odds ratio 1.18, 95% CI 1.07-1.29, P=0.0006). In prospective analyses, Gal-3 was associated with incident metabolic syndrome (hazard ratio 1.22, 95% CI 1.10-1.36, P=0.0002) and diabetes (hazard ratio 1.21, 95% CI 1.04-1.41, P=0.02), in age- and sex-adjusted, but not multivariable-adjusted models.

CONCLUSIONS

In this large, community-based sample, circulating Gal-3 was associated with abdominal adiposity, dyslipidemia, and hypertension in cross-sectional analyses, but Gal-3 did not predict incident cardiometabolic disease after adjusting for cardiometabolic risk factors. Future investigations should focus on further elucidating mechanisms linking Gal-3 with cardiometabolic disease and on assessing whether modulation of the Gal-3 pathway might have positive cardiometabolic effects.

Galectin-3 In Obesity And Type 2 Diabetes

Galectin-3 is an important regulator of inflammation and acts as a receptor for advanced-glycation (AGE) and lipoxidation end-products (ALE). Evidence indicates a significant upregulation in circulating levels and visceral adipose tissue production of Galectin-3 in obesity and type 2 diabetes. Recent studies demonstrate development of obesity and dysregulation of glucose metabolism in Galectin-3 “knockout” (KO) mice, which also develop accelerated and more severe pathology in models of atherosclerosis and metabolically-induced kidney damage. Thus, evidence that Galectin-3 is an important player in metabolic disease is accumulating. This review discusses current evidence on the connection between Galectin-3 and metabolic disease, focusing on mechanisms by which this galectin modulates adiposity, glucose metabolism and obesity-associated inflammatory responses.

Galectin-3, Renal Function, and Clinical Outcomes: Results from the LURIC and 4D Studies

Galectin-3 has been linked to incident renal disease, experimental renal fibrosis, and nephropathy. However, the association among galectin-3, renal function, and adverse outcomes has not been described. We studied this association in two large cohorts of patients over a broad range of renal function. We measured galectin-3 concentrations in baseline samples from the German Diabetes mellitus Dialysis (4D) study (1168 dialysis patients with type 2 diabetes mellitus) and the Ludwigshafen Risk and Cardiovascular Health (LURIC) study (2579 patients with coronary angiograms). Patients were stratified into three groups: eGFR of ≥90 ml/min per 1.73 m(2), 60-89 ml/min per 1.73 m(2), and <60 ml/min per 1.73 m(2). We correlated galectin-3 concentrations with demographic, clinical, and biochemical parameters. The association of galectin-3 with clinical end points was assessed by Cox proportional hazards regression within 10 years (LURIC) or 4 years (4D) of follow-up. Mean±SD galectin-3 concentrations were 12.8±4.0 ng/ml (eGFR≥90 ml/min per 1.73 m(2)), 15.6±5.4 ng/ml (eGFR 60-89 ml/min per 1.73 m(2)), 23.1±9.9 ng/ml (eGFR<60 ml/min per 1.73 m(2)), and 54.1±19.6 ng/ml (dialysis patients of the 4D study). Galectin-3 concentration was significantly associated with clinical end points in participants with impaired kidney function, but not in participants with normal kidney function. Per SD increase in log-transformed galectin-3 concentration, the risks of all-cause mortality, cardiovascular mortality, and fatal infection increased significantly. In dialysis patients, galectin-3 was associated with the combined end point of cardiovascular events. In conclusion, galectin-3 concentrations increased with progressive renal impairment and independently associated with cardiovascular end points, infections, and all-cause death in patients with impaired renal function.

Glycated serum albumin stimulates expression of endothelial cell specific molecule-1 in human umbilical vein endothelial cells: Implication in diabetes mediated endothelial dysfunction

Pro-inflammatory conditions induced by products of protein glycation in diabetes substantially enhance the risk of endothelial dysfunction and related vascular complications. Endothelial cell specific molecule-1 (ESM-1) or endocan has been demonstrated as a potential biomarker in cancer and sepsis. Its role in diabetes-induced pathologies remains unknown. The expression of ESM-1 gene is under cytokine regulation, indicating its role in endothelium-dependent pathological disorders. In this study, we investigated the effect of advanced glycated human serum albumin (AGE-HSA) on the production of ESM-1. We show that AGE-HSA exerts a modulating role on the expression of ESM-1 in human umbilical vein endothelial cells. It up-regulates expression of ESM-1 protein in a dose-dependent manner which correlates with its messenger RNA (mRNA) transcription. RAGE and galectin-3, both AGE receptors, show antagonistic action on its expression. While gene silencing of RAGE has down-regulatory effect, that of galectin-3 has up-regulatory effect on AGE-induced expression of ESM-1. Inhibition of MAPKKK and JNK pathways did not alter the expression. In contrast, phosphatidylinositol 3 kinase (PI3K) inhibition significantly up-regulated ESM-1 expression. In conclusion, these results suggest that AGE-induced activation of human umbilical vein endothelial cells promotes formation of endocan which is an endothelial dysfunction marker and may be related to vascular disease in diabetes.

Galectin-3 deficiency exacerbates hyperglycemia and the endothelial response to diabetes

Background

Diabetes promotes maladaptive changes in the endothelium that lead to its dysfunction and contribute to the vascular pathology of diabetes. We have previously reported the up-regulation of galectin-3, a β-galactoside-binding lectin, in the endothelium and sera of diabetic mice, implicating this molecule in diabetic vasculopathy and suggesting its potential as a biomarker of the disease. Therefore, we sought to assess the role of galectin-3 in the vascular pathology of diabetes.

Methods

Galectin-3 knockout mice (KO) and wild-type mice (WT) were fed either a high-fat diet (HFD) (60 % fat calories) to produce insulin resistant diabetes, or standard chow (12 % fat calories), and their metabolic and endothelial responses were measured. After 8 weeks, the aortic and skeletal muscle endothelia were isolated by fluorescence sorting of CD105⁺/CD45⁻ cells and comprehensive transcriptional analyses were performed. Transcripts differentially dysregulated by HFD in KO endothelium compared to WT were confirmed by semi-quantitative RT-PCR, and protein expression was determined by immunofluorescence of aortic and muscle tissue. Ingenuity® Pathway Analysis was used to identify pathways up-regulated by HFD in the KO, such as the coagulation cascade, and measurements of blood clotting activity were performed to confirm these results.

Results

KO mice demonstrate greater hyperglycemia and impaired glucose tolerance but lower insulin levels on HFD compared to WT. KO mice demonstrate a more robust transcriptional response to HFD in the vascular endothelium compared to WT. Transcripts dysregulated in the KO endothelium after HFD are involved in glucose uptake and insulin signaling, vasoregulation, coagulation, and atherogenesis. One of the most down-regulated transcripts in the endothelium of the KO after HFD was the glucose transporter, Glut4/Slc2a4. GLUT4 immunofluorescence confirmed lower protein abundance in the endothelium and muscle of the HFD-fed KO. Prothrombin time was decreased in the diabetic KO indicating increased coagulation activity.

Conclusions

Galectin-3 deficiency leads to exacerbated metabolic derangement and endothelial dysfunction. The impaired tissue uptake of glucose in KO mice can be attributed to the reduced expression of GLUT4. Enhanced coagulation activity in the diabetic KO suggests a protective role for galectin-3 against thrombosis. These studies demonstrate that galectin-3 deficiency contributes both to the pathogenesis of diabetes and the associated vasculopathy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0230-3) contains supplementary material, which is available to authorized users.

Galectin-3 Ablation Enhances Liver Steatosis, but Attenuates Inflammation and IL-33-Dependent Fibrosis in Obesogenic Mouse Model of Nonalcoholic Steatohepatitis

The importance of Galectin-3 (Gal-3) in obesity-associated liver pathology is incompletely defined. To dissect the role of Gal-3 in fibrotic nonalcoholic steatohepatitis (NASH), Gal-3-deficient (LGALS3(-/-)) and wild-type (LGALS3(+/+)) C57Bl/6 mice were placed on an obesogenic high fat diet (HFD, 60% kcal fat) or standard chow diet for 12 and 24 wks. Compared to WT mice, HFD-fed LGALS3(-/-) mice developed, in addition to increased visceral adiposity and diabetes, marked liver steatosis, which was accompanied with higher expression of hepatic PPAR-γ, Cd36, Abca-1 and FAS. However, as opposed to LGALS3(-/-) mice, hepatocellular damage, inflammation and fibrosis were more extensive in WT mice which had an elevated number of mature myeloid dendritic cells, proinflammatory CD11b(+)Ly6C(hi) monocytes/macrophages in liver, peripheral blood and bone marrow, and increased hepatic CCL2, F4/80, CD11c, TLR4, CD14, NLRP3 inflammasome, IL-1β and NADPH-oxidase enzymes mRNA expression. Thus, obesity-driven greater steatosis was uncoupled with attenuated fibrotic NASH in Gal-3-deficient mice. HFD-fed WT mice had a higher number of hepatocytes that strongly expressed IL-33 and hepatic CD11b(+)IL-13(+) cells, increased levels of IL-33 and IL-13 and up-regulated IL-33, ST2 and IL-13 mRNA in liver compared with LGALS3(-/-) mice. IL-33 failed to induce ST2 upregulation and IL-13 production by LGALS3(-/-) peritoneal macrophages in vitro. Administration of IL-33 in vivo enhanced liver fibrosis in HFD-fed mice in both genotypes, albeit to a significantly lower extent in LGALS3(-/-) mice, which was associated with less numerous hepatic IL-13-expressing CD11b(+) cells. The present study provides evidence of a novel role for Gal-3 in regulating IL-33-dependent liver fibrosis.

Galectin-3 in diabetic patients

Galectin-3 is a versatile molecule which exerts several and sometimes opposite functions in various pathophysiological processes. Recently, galectin-3 has gained attention as a powerful predictor of heart failure and mortality, thus becoming a useful prognostic marker in clinical practice. Moreover, though not specifically investigated in diabetic cohorts, plasma levels of galectin-3 correlated with the prevalence of diabetes and related metabolic conditions, thus suggesting that pharmacological blockade of this lectin might be successful for treating heart failure especially in subjects suffering from these disorders. Indeed, galectin-3 is considered not only as a marker of heart failure, but also as a mediator of the disease, due to its pro-fibrotic action, though evidence comes mainly from studies in galectin-3 deficient mice. However, these studies have provided contrasting results, with either attenuation or acceleration of organ fibrosis and inflammation, depending on the experimental setting and particularly on the levels of advanced glycation endproducts (AGEs)/advanced lipoxidation endproducts (ALEs), of which galectin-3 is a scavenging receptor. In fact, under conditions of increased AGE/ALE levels, galectin-3 ablation was associated with tissue-specific outcomes, reflecting the AGE/ALE-receptor function of this lectin. Conversely, in experimental models of acute inflammation and fibrosis, galectin-3 deficiency resulted in attenuation of tissue injury. There is a need for prospective studies in diabetic patients specifically investigating the relation of galectin-3 levels with complications and for further animal studies in order to establish the effective role of this lectin in organ damage before considering its pharmacological blockade in the clinical setting.

Protection from diabetes-induced atherosclerosis and renal disease by D-carnosine-octylester: effects of early vs late inhibition of advanced glycation end-products in Apoe-null mice

AIMS/HYPOTHESIS

AGEs are involved in diabetic complications and might be responsible for the phenomenon of 'hyperglycaemic memory'. D-Carnosine-octylester (DCO) has been shown to attenuate AGE formation and vascular and renal injury induced by high-fat diet in Apoe-null mice. This study aimed to verify the protective effect of DCO in atherosclerosis and renal disease induced by experimental diabetes and to discover whether reduction of AGE formation by early vs late DCO treatment provides better macro and microvascular protection.

METHODS

Apoe-null mice were rendered diabetic by streptozotocin and were left untreated or were treated with DCO for 20 weeks (DCO-Extended), from week 1 to 11 (DCO-Early) or from week 9 to 19 (DCO-Late). Non-diabetic Apoe-null mice served as controls. Aortic and renal lesions were evaluated by morphometry and protein and gene expression of disease markers were assessed by immunohistochemistry and real-time PCR.

RESULTS

DCO-Extended treatment produced a more stable plaque phenotype by markedly attenuating diabetes-induced increases in lesion size, necrotic core area and plaque content of Nε-carboxymethyllysine, levels of apoptotic cells and markers of inflammation and oxidative stress and also reductions in collagen and smooth muscle cells. DCO treatment for 11 weeks afforded partial protection and this was significantly better in DCO-Early mice than in DCO-Late mice. Renal disease was attenuated in DCO-Extended mice and to a lesser extent in those treated for 11 weeks, with no significant difference between DCO-Early mice and DCO-Late mice.

CONCLUSIONS/INTERPRETATION

These data show that DCO protects mice from diabetes-induced vascular and renal disease and that protection against atherosclerosis is more effectively achieved by early treatment than by late treatment, thus suggesting that early inhibition of AGE formation attenuates progression of macroangiopathy and favours development of more stable lesions.