Pharmacological inhibition of galectin-3 protects against hypertensive nephropathy

Galectin-3: action and clinical utility in chronic kidney disease

Chronic kidney disease is a significant cause of morbidity and mortality worldwide. In recent years, Galectin-3 has been put forward as a potential biomarker of chronic kidney disease progression. This review aims to assess the clinical utility of Galectin-3 in various pathological processes leading up to chronic kidney disease such as diabetes and lupus nephritis. We conducted a systematic search on PubMed from inception to September 2023, using the search term ("Galectin-3" OR "gal-3") AND ("renal" OR "kidney"). Galectin-3 has been shown to be both pro-fibrotic and protective against renal fibrosis through various mechanisms such as apoptotic body clearance and modulation of the Wnt pathway. Studies have found associations between raised Galectin-3, incidence and progression of chronic kidney disease. In lupus nephritis, Galectin-3 may serve as a biomarker for lupus nephritis activity. Although Galectin-3 inhibits cystogenesis, there is no correlation between total kidney volume and Galectin-3 in polycystic kidney disease. The role of Galectin-3 in staging and prognostication of renal cell carcinoma is yet to be determined. Galectin-3 has potential in predicting chronic kidney disease progression, in combination with other biomarkers. However, more trials are required given that present studies demonstrate conflicting results on the relationship between Galectin-3 and clinical outcomes in chronic kidney disease patients of varying aetiologies.

Modified Citrus Pectin (MCP) Confers a Renoprotective Effect on Early-Stage Nephropathy in Type-2 Diabetic Mice

Diabetic nephropathy (DN) is a significant global health concern with a high morbidity rate. Accumulating evidence reveals that Galectin-3 (Gal-3), a β-galactoside-binding lectin, is a biomarker in kidney diseases. Our study aimed to assess the advantageous impacts of modified citrus pectin (MCP) as an alternative therapeutic strategy for the initial and ongoing progression of DN in mice with type 2 diabetes mellitus (T2DM). The animal model has been split into four groups: control group, T2DM group (mice received intraperitoneal injections of nicotinamide (NA) and streptozotocin (STZ), T2DM+MCP group (mice received 100 mg/kg/day MCP following T2DM induction), and MCP group (mice received 100 mg/kg/day). After 4 weeks, kidney weight, blood glucose level, serum kidney function tests, histopathological structure alterations, oxidative stress, inflammation, apoptosis, and fibrosis parameters were determined in renal tissues. Our findings demonstrated that MCP treatment reduced blood glucose levels, renal histological damage, and restored kidney weight and kidney function tests. Additionally, MCP reduced malondialdehyde level and restored glutathione level, and catalase activity. MCP demonstrated a notable reduction in inflammatory and apoptosis mediators TNF-α, iNOS, TGF-βRII and caspase-3. Overall, MCP could alleviate renal injury in an experimental model of DN by suppressing renal oxidative stress, inflammation, fibrosis, and apoptosis mediators.

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.

Renal Assessment in Acute Cardiorenal Syndrome

Cardiorenal syndrome (CRS) is a complex, heterogeneous spectrum of symptoms that has kept cardiologists awake for decades. The heart failure (HF) population being burdened with multimorbidity poses diagnostic and therapeutic challenges even for experienced clinicians. Adding deteriorated renal function to the equation, which is one of the strongest predictors of adverse outcome, we measure ourselves against possibly the biggest problem in modern cardiology. With the rapid development of new renal assessment methods, we can treat CRS more effectively than ever. The presented review focuses on explaining the pathophysiology, recent advances and current practices of monitoring renal function in patients with acute CRS. Understanding the dynamic interaction between the heart and the kidney may improve patient care and support the selection of an effective and nephroprotective treatment strategy.

The potential roles of galectin-3 in AKI and CKD

Acute kidney injury (AKI) is a common condition with high morbidity and mortality, and is associated with the development and progression of chronic kidney disease (CKD). The beta-galactoside binding protein galectin-3 (Gal3), with its proinflammatory and profibrotic properties, has been implicated in the development of both AKI and CKD. Serum Gal3 levels are elevated in patients with AKI and CKD, and elevated Gal3 is associated with progression of CKD. In addition, Gal3 is associated with the incidence of AKI among critically ill patients, and blocking Gal3 in murine models of sepsis and ischemia-reperfusion injury results in significantly lower AKI incidence and mortality. Here we review the role of Gal3 in the pathophysiology of AKI and CKD, as well as the therapeutic potential of targeting Gal3.

Plasma galectin-3 concentration and estimated glomerular filtration rate in patients with type 2 diabetes with and without albuminuria

This study aimed to investigate the association between galectin-3 concentration and estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes mellitus (T2DM) with and without albuminuria. In this cross-sectional study, we examined 334 patients with T2DM. The eGFR was calculated using a creatinine-based formula (eGFR_crea) and a combined creatinine-cystatin C equation (eGFR_crea-cyst). The participants were categorized into two groups based on the urinary albumin-to-creatinine ratio (UACR): patients without albuminuria (UACR < 30 mg/g) and those with albuminuria (UACR ≥ 30 mg/g). Greater concentrations of plasma galectin-3 were associated with lower eGFR_crea-cyst and eGFR_crea levels in patients with and without albuminuria. Plasma galectin-3 concentrations were negatively correlated with eGFR_crea-cyst in patients with normoalbuminuria and albuminuria (γ = − 0.405, P < 0.001; γ = − 0.525, P < 0.001, respectively). Galectin-3 concentrations were significantly associated with eGFR_crea-cyst after adjusting for sex, age, and other confounding factors, including UACR as a categorical or continuous variable in multiple regression analyses (β = − 0.294, 95% CI − 70.804 to − 41.768, P < 0.001; β = − 0.265, 95% CI − 65.192 to − 36.550, P < 0.001, respectively). Likewise, when eGFR_crea-cyst was treated in place of eGFR_crea, this result was replicated in the correlation and regression analyses. Galectin-3 concentration was negatively associated with eGFR in patients with T2DM, independent of albuminuria status.

An Effective Sodium-Dependent Glucose Transporter 2 Inhibition, Canagliflozin, Prevents Development of Hypertensive Heart Failure in Dahl Salt-Sensitive Rats

Background: The aim of the study was to investigate the protective effect of canagliflozin (CANA) on myocardial metabolism and heart under stress overload and to further explore its possible molecular mechanism.

Methods: High-salt diet was used to induce heart failure with preserved ejection fraction (HFpEF), and then, the physical and physiological indicators were measured. The cardiac function was evaluated by echocardiography and related indicators. Masson trichrome staining, wheat germ agglutinin, and immunohistochemical staining were conducted for histology analysis. Meanwhile, oxidative stress and cardiac ATP production were also determined. PCR and Western blotting were used for quantitative detection of related genes and proteins. Comprehensive metabolomics and proteomics were employed for metabolic analysis and protein expression analysis.

Results: In this study, CANA showed diuretic, hypotensive, weight loss, and increased intake of food and water. Dahl salt-sensitive (DSS) rats fed with a diet containing 8% NaCl AIN-76A developed left ventricular remodeling and diastolic dysfunction caused by hypertension. After CANA treatment, cardiac hypertrophy and fibrosis were reduced, and the left ventricular diastolic function was improved. Metabolomics and proteomics data confirmed that CANA reduced myocardial glucose metabolism and increased fatty acid metabolism and ketogenesis in DSS rats, normalizing myocardial metabolism and reducing the myocardial oxidative stress. Mechanistically, CANA upregulated p-adenosine 5′-monophosphate-activated protein kinase (p-AMPK) and sirtuin 1 (SIRT1) and significantly induced the expression of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1a).

Conclusion: CANA can improve myocardial hypertrophy, fibrosis, and left ventricular diastolic dysfunction induced by hypertension in DSS rats, possibly through the activation of the AMPK/SIRT1/PGC-1a pathway to regulate energy metabolism and oxidative stress.

Galectin-3 in Kidney Diseases: From an Old Protein to a New Therapeutic Target

Galectin-3 (Gal-3) is a 30KDa lectin implicated in multiple pathophysiology pathways including renal damage and fibrosis. Gal-3 binds β-galactoside through its carbohydrate-recognition domain. From intra-cellular to extra-cellular localization, Gal-3 has multiple roles including transduction signal pathway, cell-to-cell adhesion, cell to extracellular matrix adhesion, and immunological chemoattractant protein. Moreover, Gal-3 has also been linked to kidney disease in both preclinical models and clinical studies. Gal-3 inhibition appears to improve renal disease in several pathological conditions, thus justifying the development of multiple drug inhibitors. This review aims to summarize the latest literature regarding Gal-3 in renal pathophysiology, from its role as a biomarker to its potential as a therapeutic agent.

Elevated plasma Galectin-3 is associated with major adverse kidney events and death after ICU admission

Background

Galectin-3 (Gal-3) is a proinflammatory and profibrotic protein especially overexpressed after Acute Kidney Injury (AKI). The early renal prognostic value of Gal-3 after AKI in critically ill patients remains unexplored. The objective was to evaluate the prognostic value of plasma level of Gal-3 for Major Adverse Kidney Events (MAKE) and mortality 30 days after ICU admission across AKI stages.

Methods

This is an ancillary study of a prospective, observational, multicenter cohort (FROG-ICU). AKI was defined using KDIGO definition.

Results

Two thousand and seventy-six patients had a Gal-3 plasma level measurement at ICU admission. Seven hundred and twenty-three (34.8%) were females and the median age was 63 [51, 74] years. Eight hundred and seven (38.9%) patients developed MAKE, 774 (37.3%) had AKI and mortality rate at 30 days was 22.4% (N = 465). Patients who developed MAKE had higher Gal-3 level at admission compared to patients without (30.2 [20.8, 49.2] ng/ml versus 16.9 [12.7, 24.3] ng/ml, p < 0.001, respectively. The area under the receiver operating characteristic curve of Gal-3 to predict MAKE was 0.76 CI_95% [0.74–0.78], p < 0.001. Gal-3 was associated with MAKE (OR 1.80 CI_95% [1.68–1.93], p < 0.001, non-adjusted and OR 1.37 CI_95% [1.27–1.49], p < 0.001, adjusted). The use of Gal-3 improved prediction performance of prediction model including SAPSII, Screat_adm, pNGAL with a NRI of 0.27 CI_95%(0.16–0.38), p < 0.001. Median Gal-3 was higher in non-survivors than in survivors at 30 days (29.2 [20.2, 49.2] ng/ml versus 18.8 [13.3, 29.2] ng/ml, p < 0.001, respectively).

Conclusion

Plasma levels of Gal-3 were strongly associated with renal function, with an increased risk of MAKE and death after ICU admission.

Trial registration ClinicalTrials.gov NCT01367093. Registered on 6 June 2011.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03878-x.

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.

Small Endogeneous Peptide Mitigates Myocardial Remodeling in a Mouse Model of Cardioselective Galectin-3 Overexpression

BACKGROUND

Myocardial Gal3 (galectin-3) expression is associated with cardiac inflammation and fibrosis. Increased Gal3 portends susceptibility to heart failure and death. There are no data reporting the causative role of Gal3 to mediate cardiac fibro-inflammatory response and heart failure.

METHODS

We developed a cardioselective Gal3 gain-of-function mouse (Gal3+/+) using α-myosin heavy chain promotor. We confirmed Gal3-transgene expression with real-time polymerase chain reaction and quantified cardiac/circulating Gal3 with Western blot and immunoassays. We used echocardiogram and cardiac magnetic resonance imaging to measure cardiac volumes, function, and myocardial velocities. Ex vivo, we studied myocardial inflammation/fibrosis and downstream TGF (transforming growth factor) β1-mRNA expression. We examined the effects of acute myocardial ischemia in presence of excess Gal3 by inducing acute myocardial infarction in mice. Two subsets of mice including mice treated with N-acetyl-seryl-aspartyl-lysyl-proline (a Gal3-inhibitor) and mice with genetic Gal3 loss-of-function (Gal3-/-) were studied for comparative analysis of Gal3 function.

RESULTS

Gal3+/+ mice had increased cardiac/circulating Gal3. Gal3+/+ mice showed excess pericardial fat pad, dilated ventricles and cardiac dysfunction, which was partly normalized by N-acetyl-seryl-aspartyl-lysyl-proline. Cardiac magnetic resonance imaging showed reduced myocardial contractile velocities in Gal3+/+. The majority of Gal3+/+ mice did not survive acute myocardial infarction, and the survivors had profound cardiac dysfunction. Myocardial histology of Gal3+/+ mice showed macrophage/mast-cell infiltration, fibrosis and higher TGFβ1-mRNA expression, which were mitigated by both Gal3 gene deletion and N-acetyl-seryl-aspartyl-lysyl-proline administration.

CONCLUSIONS

Our study shows that cardioselective Gal3 overexpression leads to multiple cardiac phenotypic defects including ventricular dilation and cardiac dysfunction. Pharmacological Gal3 inhibition conferred protective effects with reduction of inflammation and fibrosis. Our study highlights the importance of translational studies to counteract Gal3 function and prevent cardiac dysfunction.

Galectin-3 and Risk of Late Graft Failure in Kidney Transplant Recipients: A 10-year Prospective Cohort Study

BACKGROUND

Galectin-3 may play a causal role in kidney inflammation and fibrosis, which may also be involved in the development of kidney graft failure. With novel galectin-3-targeted pharmacological therapies increasingly coming available, we aimed to investigate whether galectin-3 is associated with risk of late graft failure in kidney transplant recipients (KTR).

METHODS

We studied adult KTR who participated in TransplantLines Insulin Resistance and Inflammation Biobank and Cohort Study, recruited in a university setting (2001-2003). Follow-up was performed for a median of 9.5 (interquartile range, 6.2-10.2) years. Overall and stratified (Pinteraction < 0.05) multivariable-adjusted Cox proportional-hazards regression analyses were performed to study the association of galectin-3 with risk of graft failure (restart of dialysis or retransplantation).

RESULTS

Among 561 KTR (age 52 ± 12 y; 54% males), baseline median galectin-3 was 21.1 (interquartile range, 17.0-27.2) ng/mL. During follow-up, 72 KTR developed graft failure (13, 18, and 44 events over increasing tertiles of galectin-3). Independent of adjustment for donor, recipient, and transplant characteristics, galectin-3-associated with increased risk of graft failure (hazard ratios [HR] per 1 SD change, 2.12; 95% confidence interval [CI], 1.63-2.75; P < 0.001), particularly among KTR with systolic blood pressure ≥140 mmHg (HR, 2.29; 95% CI, 1.80-2.92; P < 0.001; Pinteraction = 0.01) or smoking history (HR, 2.56; 95% CI, 1.95-3.37; P < 0.001; Pinteraction = 0.03). Similarly, patients in the highest tertile of galectin-3 were consistently at increased risk of graft failure.

CONCLUSIONS

Serum galectin-3 levels are elevated in KTR, and independently associated with increased risk of late graft failure. Whether galectin-3-targeted therapies may represent novel opportunities to decrease the long-standing high burden of late graft failure in stable KTR warrants further studies.

Galectin-3 in septic acute kidney injury: a translational study

BACKGROUND

Galectin-3 (Gal-3) is a pleiotropic glycan-binding protein shown to be involved in sepsis and acute kidney injury (AKI). However, its role has never been elucidated in sepsis-associated AKI (S-AKI). We aimed to explore Gal-3's role and its potential utility as a therapeutic target in S-AKI.

METHODS

In 57 patients admitted to the intensive care unit (ICU) with sepsis, serum Gal-3 was examined as a predictor of ICU mortality and development of AKI. In a rat model of S-AKI induced by cecal ligation and puncture (CLP), 7-day mortality and serum Gal-3, Interleukin-6 (IL-6), and creatinine were examined at 2, 8, and 24 hours (h) post-CLP. Two experimental groups received the Gal-3 inhibitor modified citrus pectin (P-MCP) at 400 mg/kg/day and 1200 mg/kg/day, while the control group received water only (n = 18 in each group).

RESULTS

Among 57 patients, 27 developed AKI and 8 died in the ICU. Serum Gal-3 was an independent predictor of AKI (OR = 1.2 [95% CI 1.1-1.4], p = 0.01) and ICU mortality (OR = 1.4 [95% CI 1.1-2.2], p = 0.04) before and after controlling for age, AKI, and acute physiology and chronic health evaluation (APACHE II) score. In the CLP rat experiment, serum Gal-3 peaked earlier than IL-6. Serum Gal-3 was significantly lower in both P-MCP groups compared to control at 2 h post-CLP (400 mg: p = 0.003; 1200 mg: p = 0.002), and IL-6 was significantly lower in both P-MCP groups at all time points with a maximum difference at 24 h post-CLP (400 mg: p = 0.015; 1200 mg: p = 0.02). In the Gal-3 inhibitor groups, 7-day mortality was significantly reduced from 61% in the control group to 28% (400 mg P-MCP: p = 0.03) and 22% (1200 mg P-MCP: p = 0.001). Rates of AKI per RIFLE criteria were significantly reduced from 89% in the control group to 44% in both P-MCP groups (400 mg: p = 0.007; 1200 mg: p = 0.007).

CONCLUSIONS

This translational study demonstrates the importance of Gal-3 in the pathogenesis of S-AKI, and its potential utility as a therapeutic target.

Effects of Sodium-Glucose Co-transporter 2 Inhibition with Empaglifozin on Renal Structure and Function in Non-diabetic Rats with Left Ventricular Dysfunction After Myocardial Infarction

Background

The use of sodium–glucose co-transporter 2 inhibitors (SGLT2i) is currently expanding to cardiovascular risk reduction in non-diabetic subjects, but renal (side-)effects are less well studied in this setting.

Methods

Male non-diabetic Sprague Dawley rats underwent permanent coronary artery ligation to induce MI, or sham surgery. Rats received chow containing empagliflozin (EMPA) (30 mg/kg/day) or control chow. Renal function and electrolyte balance were measured in metabolic cages. Histological and molecular markers of kidney injury, parameters of phosphate homeostasis and bone resorption were also assessed.

Results

EMPA resulted in a twofold increase in diuresis, without evidence for plasma volume contraction or impediments in renal function in both sham and MI animals. EMPA increased plasma magnesium levels, while the levels of glucose and other major electrolytes were comparable among the groups. Urinary protein excretion was similar in all treatment groups and no histomorphological alterations were identified in the kidney. Accordingly, molecular markers for cellular injury, fibrosis, inflammation and oxidative stress in renal tissue were comparable between groups. EMPA resulted in a slight increase in circulating phosphate and PTH levels without activating FGF23–Klotho axis in the kidney and bone mineral resorption, measured with CTX-1, was not increased.

Conclusions

EMPA exerts profound diuretic effects without compromising renal structure and function or causing significant electrolyte imbalance in a non-diabetic setting. The slight increase in circulating phosphate and PTH after EMPA treatment was not associated with evidence for increased bone mineral resorption suggesting that EMPA does not affect bone health.

Electronic supplementary material

The online version of this article (10.1007/s10557-020-06954-6) contains supplementary material, which is available to authorized users.

Pharmacological Inhibition of Galectin-3 Ameliorates Diabetes-Associated Cognitive Impairment, Oxidative Stress and Neuroinflammation in vivo and in vitro

Background

In diabetes, cognitive impairment is linked with oxidative stress and neuroinflammation. As the only chimeric member of the galectin family, galectin-3 (Gal3) induces neuroinflammation and cognitive impairment in models of Alzheimer’s disease (AD); however, its role in diabetes-associated cognitive impairment is not established.

Methodology

Here, we investigated the effects of Gal3 inhibition on cognitive impairment and the possible underlying molecular events in diabetes. We investigated the effects of the Gal3 inhibitor modified citrus pectin (MCP; 100 mg/kg/day oral for 6 weeks) in vivo in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic rats. Additionally, the effects of MCP on high glucose (HG)-stimulated BV-2 microglial cells were investigated in vitro.

Results

We found that MCP attenuated memory impairment in diabetic rats in the Morris water maze test and reduced insulin resistance, oxidative stress, and neuroinflammation. In HG-stimulated BV-2 microglial cells, MCP increased cell viability and decreased oxidative stress and the production of proinflammatory cytokines.

Conclusion

The results of this study indicate that the inhibition of Gal3 by MCP ameliorates diabetes-associated cognitive impairment, oxidative stress, and neuroinflammation, suggesting that Gal3 could be a potential new target for therapeutic intervention to prevent cognitive impairment in diabetes.

Lifestyle, Inflammation, and Vascular Calcification in Kidney Transplant Recipients: Perspectives on Long-Term Outcomes

After decades of pioneering and improvement, kidney transplantation is now the renal replacement therapy of choice for most patients with end-stage kidney disease (ESKD). Where focus has traditionally been on surgical techniques and immunosuppressive treatment with prevention of rejection and infection in relation to short-term outcomes, nowadays, so many people are long-living with a transplanted kidney that lifestyle, including diet and exposure to toxic contaminants, also becomes of importance for the kidney transplantation field. Beyond hazards of immunological nature, a systematic assessment of potentially modifiable-yet rather overlooked-risk factors for late graft failure and excess cardiovascular risk may reveal novel targets for clinical intervention to optimize long-term health and downturn current rates of premature death of kidney transplant recipients (KTR). It should also be realized that while kidney transplantation aims to restore kidney function, it incompletely mitigates mechanisms of disease such as chronic low-grade inflammation with persistent redox imbalance and deregulated mineral and bone metabolism. While the vicious circle between inflammation and oxidative stress as common final pathway of a multitude of insults plays an established pathological role in native chronic kidney disease, its characterization post-kidney transplant remains less than satisfactory. Next to chronic inflammatory status, markedly accelerated vascular calcification persists after kidney transplantation and is likewise suggested a major independent mechanism, whose mitigation may counterbalance the excess risk of cardiovascular disease post-kidney transplant. Hereby, we first discuss modifiable dietary elements and toxic environmental contaminants that may explain increased risk of cardiovascular mortality and late graft failure in KTR. Next, we specify laboratory and clinical readouts, with a postulated role within persisting mechanisms of disease post-kidney transplantation (i.e., inflammation and redox imbalance and vascular calcification), as potential non-traditional risk factors for adverse long-term outcomes in KTR. Reflection on these current research opportunities is warranted among the research and clinical kidney transplantation community.

Interaction between galectin-3 and cystinosin uncovers a pathogenic role of inflammation in kidney involvement of cystinosis

Inflammation is involved in the pathogenesis of many disorders. However, the underlying mechanisms are often unknown. Here, we test whether cystinosin, the protein involved in cystinosis, is a critical regulator of galectin-3, a member of the β-galactosidase binding protein family, during inflammation. Cystinosis is a lysosomal storage disorder and, despite ubiquitous expression of cystinosin, the kidney is the primary organ impacted by the disease. Cystinosin was found to enhance lysosomal localization and degradation of galectin-3. In Ctns-/- mice, a mouse model of cystinosis, galectin-3 is overexpressed in the kidney. The absence of galectin-3 in cystinotic mice ameliorates pathologic renal function and structure and decreases macrophage/monocyte infiltration in the kidney of the Ctns-/-Gal3-/- mice compared to Ctns-/- mice. These data strongly suggest that galectin-3 mediates inflammation involved in kidney disease progression in cystinosis. Furthermore, galectin-3 was found to interact with the pro-inflammatory cytokine Monocyte Chemoattractant Protein-1, which stimulates the recruitment of monocytes/macrophages, and proved to be significantly increased in the serum of Ctns-/- mice and also patients with cystinosis. Thus, our findings highlight a new role for cystinosin and galectin-3 interaction in inflammation and provide an additional mechanistic explanation for the kidney disease of cystinosis. This may lead to the identification of new drug targets to delay cystinosis progression.

New Therapies for the Treatment of Renal Fibrosis

Renal fibrosis is the common pathway for progression of chronic kidney disease (CKD) to end stage of renal disease. It is now widely accepted that the degree of renal fibrosis correlates with kidney function and CKD stages. The key cellular basis of renal fibrosis includes activation of myofibroblasts, excessive production of extracellular matrix components, and infiltration of inflammatory cells. Many cellular mechanisms responsible for renal fibrosis have been identified, and some antifibrotic agents show a greater promise in slowing down and even reversing fibrosis in animal models; however, translating basic findings into effective antifibrotic therapies in human has been limited. In this chapter, we will discuss the effects and mechanisms of some novel antifibrotic agents in both preclinical studies and clinical trials.

Galectin 3 inhibition attenuates renal injury progression in cisplatin-induced nephrotoxicity

Nephrotoxicity is a major toxic effect in chemotherapy, which constitutes up to 60% of hospitalized acute kidney injury (AKI). Very few treatment options exist to slow the transition from AKI to subsequent chronic kidney diseases (CKD). Here, we demonstrate that galectin-3 (Gal-3), a β-galactoside binding lectin that plays an important role in kidney fibrosis and renal failure, is one of the key factors for renal injury progression. Ectopic overexpression of Gal-3 significantly decreased the viability of HEK293, simultaneously inducing of cell cycle arrest and apoptosis. However, inhibition of Gal-3, mediated by modified citrus pectin (MCP), predominantly antagonized the pro-apoptotic effects. Mice were pre-treated with normal or 1% MCP-supplemented drinking water 1 week before cisplatin injection. Analyses of serum creatinine and renal tissue damage indicated that MCP-treated mice demonstrated increased renal function and attenuated renal fibrosis after cisplatin-induced injury. MCP-treated mice also demonstrated decreased renal fibrosis and apoptosis, as revealed by masson trichrome staining and Western blot analysis of cleaved caspase-3. Additionally, the protective role of Gal-3 inhibition in the kidney injury was shown to be mediated by protein kinase C α (PKC-α), which promoted cell apoptosis and collagen I synthesis in HEK293 cells. These results demonstrated the potential Gal-3 and PKC-α as therapeutic targets for the treatment of AKI and CKD.

Galectin-3 is independently associated with progression of nephropathy in type 2 diabetes mellitus

AIMS/HYPOTHESIS

Galectin-3 has been implicated in cardiac and renal fibrosis and serves as a prognostic clinical indicator in heart failure. The aim of the present study was to evaluate whether serum galectin-3 level is associated with progressive kidney disease in type 2 diabetes.

METHODS

Galectin-3 was measured in baseline samples by ELISA in 1320 participants with type 2 diabetes with eGFR ≥30 ml min^-1 1.73 m^-2. The primary outcome was defined as doubling of serum creatinine and/or initiation of renal replacement therapy during follow-up. The secondary outcome was progression to macroalbuminuria in individuals with normo- or microalbuminuria at baseline.

RESULTS

Serum galectin-3 levels were significantly increased in a random subgroup of 270 type 2 diabetic individuals with eGFR >60 ml min^-1 1.73 m^-2 compared with an age- and sex-matched non-diabetic control group (7.58 ± 2.29 ng/ml vs 6.10 ± 1.91 ng/ml, respectively, p < 0.01). In the whole diabetic cohort, after a mean follow-up of 9 years, galectin-3 was independently associated with doubling of serum creatinine (HR 1.19; 95% CI 1.14, 1.24, p < 0.001) and incident macroalbuminuria (HR 1.20; 95% CI 1.12, 1.30, p < 0.001), even after adjusting for traditional risk factors, baseline eGFR and albuminuria status. Individuals with galectin-3 levels in the highest quartile had a fourfold risk of renal function loss and threefold risk of incident macroalbuminuria.

CONCLUSIONS/INTERPRETATION

Serum galectin-3 was independently associated with progressive renal disease in type 2 diabetes. Further mechanistic studies are warranted to determine whether galectin-3 is simply a disease biomarker or is also a mediator of the development and progression of diabetic nephropathy.

Novel heart failure biomarkers: why do we fail to exploit their potential?

Plasma biomarkers are useful tools in the diagnosis and prognosis of heart failure (HF). In the last decade, numerous studies have aimed to identify novel HF biomarkers that would provide superior and/or additional diagnostic, prognostic, or stratification utility. Although numerous biomarkers have been identified, their implementation in clinical practice has so far remained largely unsuccessful. Whereas cardiac-specific biomarkers, including natriuretic peptides (ANP and BNP) and high sensitivity troponins (hsTn), are widely used in clinical practice, other biomarkers have not yet proven their utility. Galectin-3 (Gal-3) and soluble suppression of tumorigenicity 2 (sST2) are the only novel HF biomarkers that are included in the ACC/AHA HF guidelines, but their clinical utility still needs to be demonstrated. In this review, we will describe natriuretic peptides, hsTn, and novel HF biomarkers, including Gal-3, sST2, human epididymis protein 4 (HE4), insulin-like growth factor-binding protein 7 (IGFBP-7), heart fatty acid-binding protein (H-FABP), soluble CD146 (sCD146), interleukin-6 (IL-6), growth differentiation factor 15 (GDF-15), procalcitonin (PCT), adrenomedullin (ADM), microRNAs (miRNAs), and metabolites like 5-oxoproline. We will discuss the biology of these HF biomarkers and conclude that most of them are markers of general pathological processes like fibrosis, cell death, and inflammation, and are not cardiac- or HF-specific. These characteristics explain to a large degree why it has been difficult to relate these biomarkers to a single disease. We propose that, in addition to clinical investigations, it will be pivotal to perform comprehensive preclinical biomarker investigations in animal models of HF in order to fully reveal the potential of these novel HF biomarkers.

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.

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

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

Renal fibrosis: Recent translational aspects

Renal fibrogenesis is the common final pathway to all renal injuries that consequently leads to Chronic Kidney Disease (CKD). Renal fibrogenesis corresponds to the replacement of renal functional tissue by extra-cellular matrix proteins, mainly collagens, that ultimately impairs kidney function. Blockade of the renin angiotensin system by Angiotensin Converting Enzyme inhibitors (ACEi) or Angiotensin Receptor Blockers (ARBs) was the first strategy that proved efficient to blunt the development of renal fibrogenesis independently of its systemic action on blood pressure. Although this strategy has been published 20years ago, there is to date no novel therapeutic targets that are both safe and efficient in hindering renal fibrogenesis and CKD in humans, nor there is any new biomarker to precisely quantify this process. In our review, we will focus on the most recent pathways leading to fibrogenesis which have a high therapeutic potential in humans and on the most promising biomarkers of renal fibrosis.

Vaccarin alleviates hypertension and nephropathy in renovascular hypertensive rats

The kidney is an important organ in the regulation of blood pressure, and it is also one of the primary target organs of hypertension. Kidney damage in response to hypertension eventually leads to renal insufficiency. The authors previously demonstrated that vaccarin exhibits a protective role in endothelial injury. However, the effects of vaccarin on the two-kidney, one clip (2K1C) renovascular hypertension model and subsequent kidney injury have yet to be fully elucidated. The present study was designed to investigate the roles and mechanisms of vaccarin in attenuating hypertension and whether vaccarin had beneficial effects on kidney injury. The 2K1C rats had greater fibrosis, apoptosis, reactive oxygen species production, inflammation, angiotensin II (Ang II) and angiotensin type 1 (AT1) receptors in the right kidney compared with normotensive rats, which were alleviated by a high dose of vaccarin and captopril. Vaccarin treatment attenuated hypertension, reduced fibrosis markers, NADPH oxidase (NOX)-2, NOX-4, 3-nitrotyrosine, tumor necrosis factor-α, interleukin 1β (IL-1β), and IL-6 protein levels and altered pro-apoptotic protein levels including caspase-3, anti-apoptosis protein B cell lymphoma (Bcl)-2 and Bcl-2 associated X, apoptosis regulator in the right kidney of 2K1C rats. These findings suggest that the protective effects of vaccarin on the right kidney in renovascular hypertension are possibly due to downregulation of fibrosis, inflammatory molecules, oxidative stress, Ang II, and AT1 receptor levels.

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.

New Pharmacologic Agents That Target Inflammation and Fibrosis in Nonalcoholic Steatohepatitis-Related Kidney Disease

Epidemiologic data show an association between the prevalence and severity of nonalcoholic fatty liver disease and the incidence and stage of chronic kidney disease (CKD); furthermore, nonalcoholic steatohepatitis (NASH)-related cirrhosis has a higher risk of renal failure, a greater necessity for simultaneous liver-kidney transplantation, and a poorer renal outcome than cirrhosis of other etiologies even after simultaneous liver-kidney transplantation. These data suggest that NASH and CKD share common proinflammatory and profibrotic mechanisms of progression, which are targeted incompletely by current treatments. We reviewed therapeutic approaches to late preclinical/early clinical stage of development in NASH and/or CKD, focusing on anti-inflammatory and antifibrotic treatments, which could slow the progression of both disease conditions. Renin inhibitors and angiotensin-converting enzyme-2 activators are new renin-angiotensin axis modulators that showed incremental advantages over angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers in preclinical models. Novel, potent, and selective agonists of peroxisome proliferator-activated receptors and of farnesoid X receptor, designed to overcome limitations of older compounds, showed promising results in clinical trials. Epigenetics, heat stress response, and common effectors of redox regulation also were subjected to intensive research, and the gut was targeted by several approaches, including synbiotics, antilipopolysaccharide antibodies, Toll-like receptor-4 antagonists, incretin mimetics, and fibroblast growth factor 19 analogs. Promising anti-inflammatory therapies include inhibitors of NOD-like receptor family, pyrin domain containing 3 inflammasome, of nuclear factor-κB, and of vascular adhesion protein-1, chemokine antagonists, and solithromycin, and approaches targeting common profibrogenic pathways operating in the liver and the kidney include galectin-3 antagonists, and inhibitors of rho-associated protein kinase and of epidermal growth factor activation. The evidence, merits, and limitations of each approach for the treatment of NASH and CKD are discussed.

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 Blockade Reduces Renal Fibrosis in Two Normotensive Experimental Models of Renal Damage

Background

Galectin-3 (Gal-3), a β-galactoside-binding lectin, is increased in kidney injury and its pharmacological blockade reduces renal damage in acute kidney injury, hyperaldosteronism or hypertensive nephropathy. We herein investigated the effects of pharmacological Gal-3 inhibition by modified citrus pectin (MCP) in early renal damage associated with obesity and aortic stenosis (AS).

Results

Gal-3 was upregulated in kidneys from high fat diet (HFD) rats and in animals with partial occlusion of ascending aorta (AS). Urinary and plasma neutrophil gelatinase-associated lipocalin (NGAL) and urinary albumin were enhanced in HFD and AS rats. In kidney from obese rats, fibrotic markers (collagen, TFG-β), epithelial-mesenchymal transition molecules (α-smooth muscle actin, E-cadherin), inflammatory mediator (osteopontin) and kidney injury marker (kidney injury molecule-1) were modified. In kidney from AS rats, fibrotic markers (collagen, CTGF), epithelial-mesenchymal transition molecules (fibronectin, α-smooth muscle actin, β-catenin, E-cadherin) and kidney injury markers (NGAL, kidney injury molecule-1) were altered. Histologic observations of obese and AS rat kidneys revealed tubulointerstitial fibrosis. The pharmacological inhibition of Gal-3 with MCP normalized renal Gal-3 levels as well as functional, histological and molecular alterations in obese and AS rats.

Conclusions

In experimental models of mild kidney damage, the increase in renal Gal-3 expression paralleled with renal fibrosis, inflammation and damage, while these alterations were prevented by Gal-3 blockade. These data suggest that Gal-3 could be a new player in renal molecular, histological and functional alterations at early stages of kidney damage.

Fatty Liver and Chronic Kidney Disease: Novel Mechanistic Insights and Therapeutic Opportunities

Chronic kidney disease (CKD) is a risk factor for end-stage renal disease (ESRD) and cardiovascular disease (CVD). ESRD or CVD develop in a substantial proportion of patients with CKD receiving standard-of-care therapy, and mortality in CKD remains unchanged. These data suggest that key pathogenetic mechanisms underlying CKD progression go unaffected by current treatments. Growing evidence suggests that nonalcoholic fatty liver disease (NAFLD) and CKD share common pathogenetic mechanisms and potential therapeutic targets. Common nutritional conditions predisposing to both NAFLD and CKD include excessive fructose intake and vitamin D deficiency. Modulation of nuclear transcription factors regulating key pathways of lipid metabolism, inflammation, and fibrosis, including peroxisome proliferator-activated receptors and farnesoid X receptor, is advancing to stage III clinical development. The relevance of epigenetic regulation in the pathogenesis of NAFLD and CKD is also emerging, and modulation of microRNA21 is a promising therapeutic target. Although single antioxidant supplementation has yielded variable results, modulation of key effectors of redox regulation and molecular sensors of intracellular energy, nutrient, or oxygen status show promising preclinical results. Other emerging therapeutic approaches target key mediators of inflammation, such as chemokines; fibrogenesis, such as galectin-3; or gut dysfunction through gut microbiota manipulation and incretin-based therapies. Furthermore, NAFLD per se affects CKD through lipoprotein metabolism and hepatokine secretion, and conversely, targeting the renal tubule by sodium-glucose cotransporter 2 inhibitors can improve both CKD and NAFLD. Implications for the treatment of NAFLD and CKD are discussed in light of this new therapeutic armamentarium.

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.

Functions and mechanisms of microglia/macrophages in neuroinflammation and neurogenesis after stroke

Microglia/macrophages are the major immune cells involved in the defence against brain damage. Their morphology and functional changes are correlated with the release of danger signals induced by stroke. These cells are normally responsible for clearing away dead neural cells and restoring neuronal functions. However, when excessively activated by the damage-associated molecular patterns following stroke, they can produce a large number of proinflammatory cytokines that can disrupt neural cells and the blood-brain barrier and influence neurogenesis. These effects indicate the important roles of microglia/macrophages in the pathophysiological processes of stroke. However, the modifiable and adaptable nature of microglia/macrophages may also be beneficial for brain repair and not just result in damage. These distinct roles may be attributed to the different microglia/macrophage phenotypes because the M1 population is mainly destructive, while the M2 population is neuroprotective. Additionally, different gene expression signature changes in microglia/macrophages have been found in diverse inflammatory milieus. These biofunctional features enable dual roles for microglia/macrophages in brain damage and repair. Currently, it is thought that the proper inflammatory milieu may provide a suitable microenvironment for neurogenesis; however, detailed mechanisms underlying the inflammatory responses that initiate or inhibit neurogenesis remain unknown. This review summarizes recent progress concerning the mechanisms involved in brain damage, repair and regeneration related to microglia/macrophage activation and phenotype transition after stroke. We also argue that future translational studies should be targeting multiple key regulating molecules to improve brain repair, which should be accompanied by the concept of a "therapeutic time window" for sequential therapies.

Connecting heart failure with preserved ejection fraction and renal dysfunction: the role of endothelial dysfunction and inflammation

Renal dysfunction in heart failure with preserved ejection fraction (HFpEF) is common and is associated with increased mortality. Impaired renal function is also a risk factor for developing HFpEF. A new paradigm for HFpEF, proposing a sequence of events leading to myocardial remodelling and dysfunction in HFpEF, was recently introduced, involving inflammatory, microvascular, and cardiac components. The kidney might play a key role in this systemic process. Renal impairment causes metabolic and systemic derangements in circulating factors, causing an activated systemic inflammatory state and endothelial dysfunction, which may lead to cardiomyocyte stiffening, hypertrophy, and interstitial fibrosis via cross-talk between the endothelium and cardiomyocyte compartments. Here, we review the role of endothelial dysfunction and inflammation to explain the link between renal dysfunction and HFpEF, which allows for identification of new early risk markers, prognostic factors, and unique targets for intervention.

Galectin-3 and post-myocardial infarction cardiac remodeling

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