Galectins in the Pathogenesis of Cerebrovascular Accidents: An Overview

Advances in development of biomarkers for brain damage and ischemia

Acquired brain injury is an urgent situation that requires rapid diagnosis and treatment. Magnetic resonance imaging (MRI) and computed tomography (CT) are required for accurate diagnosis. However, these methods are costly and require substantial infrastructure and specialized staff. Circulatory biomarkers of acute brain injury may help in the management of patients with acute cerebrovascular events and prevent poor outcome and mortality. The purpose of this review is to provide an overview of the development of potential biomarkers of brain damage to increase diagnostic possibilities. For this purpose, we searched the PubMed database of studies on the diagnostic potential of brain injury biomarkers. We also accessed information from Clinicaltrials.gov to identify any clinical trials of biomarker measurements for the diagnosis of brain damage. In total, we present 41 proteins, enzymes and hormones that have been considered as biomarkers for brain injury, of which 20 have been studied in clinical trials. Several microRNAs have also emerged as potential clinical biomarkers for early diagnosis. Combining multiple biomarkers in a panel, along with other parameters, is yielding promising outcomes.

Association between galectin-3 and the prognosis of patients with stroke: A meta-analysis of observational studies

AIM

This meta-analysis aimed to investigate the prognostic value of galectin-3 among patients with stroke.

DATA SYNTHESIS

Electronic databases, such as PubMed, Web of Science, Embase, Cochrane, and Clinical Trials, were utilized for conducting searches from database inception to November 2022. Two reviewers independently screened the papers, extracted the data, and used the Newcastle-Ottawa Scale to determine the risk of bias. Stata 17 was employed to conduct the meta-analysis, while the funnel plot was utilized to identify potential publication bias. Subgroup and meta-regression analyses were employed to examine the sources of heterogeneity. Nine studies that satisfied the inclusion criteria were included. Galectin-3 levels were higher post-stroke in patients with poor outcomes and mortality compared to those in patients with good outcomes (standardized mean difference [SMD], 2.83; 95 % confidence interval [CI], 1.25-4.40; P<0.001) and stroke survivors (SMD, 1.18; 95 % CI, 0.96-1,39; P< 0.001), and elevated galectin-3 levels were associated with poor stroke outcomes (odds ratio [OR], 1.19; 95 % CI, 1.06-1.33; P<0.001). Further, higher post-stroke galectin-3 levels were associated with a higher risk of mortality (OR, 1.16; 95 % CI, 1.08-1.25; P<0.001), and this relationship was maintained after trim-and-fill analyses (OR, 1.14; 95 % CI, 1.06-1.22).

CONCLUSIONS

Galectin-3 levels post-stroke are increased in patients with a poor prognosis, and this elevation is associated with poor stroke outcomes and mortality. It is recommended that further high-caliber investigations with expanded sample sizes corroborate the outcomes of this study.

Neuroinflammation and galectins: a key relationship in neurodegenerative diseases

Neurodegeneration is a pathological condition that is associated with the loss of neuronal function and structure. In neurodegenerative diseases, mounting evidence indicates that neuroinflammation is a common factor that contributes to neuronal damage and neurodegeneration. Neuroinflammation is characterized by the activation of microglia, the neuroimmune cells of the central nervous system (CNS), which have been implicated as active contributors to neuronal damage. Glycan structure modification is defining the outcome of neuroinflammation and neuronal regeneration; moreover, the expression of galectins, a group of lectins that specifically recognize β-galactosides, has been proposed as a key factor in neuronal regeneration and modulation of the inflammatory response. Of the different galectins identified, galectin-1 stimulates the secretion of neurotrophic factors in astrocytes and promotes neuronal regeneration, whereas galectin-3 induces the proliferation of microglial cells and modulates cell apoptosis. Galectin-8 emerged as a neuroprotective factor, which, in addition to its immunosuppressive function, could generate a neuroprotective environment in the brain. This review describes the role of galectins in the activation and modulation of astrocytes and microglia and their anti- and proinflammatory functions within the context of neuroinflammation. Furthermore, it discusses the potential use of galectins as a therapeutic target for the inflammatory response and remodeling in damaged tissues in the central nervous system.

Human Galectin-7 Gene LGALS7 Promoter Sequence Polymorphisms and Risk of Spontaneous Intracerebral Hemorrhage: A Prospective Study

Background and purpose

Despite evidence for the role of genetic factors in stroke, only a small proportion of strokes have been clearly attributed to monogenic factors, due to phenotypic heterogeneity. The goal of this study was to determine whether a significant relationship exists between human galectin-7 gene LGALS7 promoter region polymorphisms and the risk of stroke due to non-traumatic intracerebral hemorrhage (ICH).

Methods

This two-stage genetic association study included an initial exploratory stage followed by a discovery stage. During the exploratory stage, transgenic galectin-7 mice or transgenic mice with the scrambled sequence of the hairpin structure –silenced down gene LGALS7—were generated and then expressed differentially expressed proteins and galectin-7-interacting proteins were identified through proteomic analysis. During the discovery stage, a single-nucleotide polymorphism (SNP) genotyping approach was used to determine associations between 2 LGALS7 SNPs and ICH stroke risk for a cohort of 24 patients with stroke of the Chinese Han population and 70 controls.

Results

During the exploratory phase, LGALS7 expression was found to be decreased in TGLGALS–DOWN mice as compared to its expression in TGLGALS mice. During the discovery phase, analysis of LGALS7 sequences of 24 non-traumatic ICH cases and 70 controls led to the identification of 2 ICH susceptibility loci: a genomic region on 19q13.2 containing two LGALS7 SNPs, rs567785577 and rs138945880, whereby the A allele of rs567785577 and the T allele of rs138945880 were associated with greater risk of contracting ICH [for T and A vs. C and G, unadjusted odds ratio (OR) = 13.5; 95% CI = 2.249–146.5; p = 0.002]. This is the first study to genotype the galectin-7 promoter in patients with hemorrhagic stroke. Genotype and allele association tests and preliminary analysis of patients with stroke revealed that a single locus may be a genetic risk factor for hemorrhagic stroke.

Conclusion

A and T alleles of two novel SNP loci of 19q13.2, rs567785577 and rs138945880, respectively, were evaluated for associations with susceptibility to ICH. Further studies with expanded case numbers that include subjects of other ethnic populations are needed to elucidate mechanisms underlying associations between these SNPs and ICH risk.

Galectins in the Pathogenesis of Common Retinal Disease

Diseases of the retina are major causes of visual impairment and blindness in developed countries and, due to an ageing population, their prevalence is continually rising. The lack of effective therapies and the limitations of those currently in use highlight the importance of continued research into the pathogenesis of these diseases. Vascular endothelial growth factor (VEGF) plays a major role in driving vascular dysfunction in retinal disease and has therefore become a key therapeutic target. Recent evidence also points to a potentially similarly important role of galectins, a family of β-galactoside-binding proteins. Indeed, they have been implicated in regulating fundamental processes, including vascular hyperpermeability, angiogenesis, neuroinflammation, and oxidative stress, all of which also play a prominent role in retinopathies. Here, we review direct evidence for pathological roles of galectins in retinal disease. In addition, we extrapolate potential roles of galectins in the retina from evidence in cancer, immune and neuro-biology. We conclude that there is value in increasing understanding of galectin function in retinal biology, in particular in the context of the retinal vasculature and microglia. With greater insight, recent clinical developments of galectin-targeting drugs could potentially also be of benefit to the clinical management of many blinding diseases.

Galectin-3 protects against ischemic stroke by promoting neuro-angiogenesis via apoptosis inhibition and Akt/Caspase regulation

Post-stroke neurological deficits and mortality are often associated with vascular disruption and neuronal apoptosis. Galectin-3 (Gal3) is a potent pro-survival and angiogenic factor. However, little is known about its protective role in the cerebral ischemia/reperfusion (I/R) injury. We have previously shown significant up-regulation of Gal3 in the post-stroke rat brain, and that blocking of Gal3 with neutralizing antibody decreases the cerebral blood vessel density. Our current study demonstrates that intracerebral local delivery of the Gal3 into rat brain at the time of reperfusion exerts neuroprotection. Ischemic lesion volume and neuronal cell death were significantly reduced as compared with the vehicle-treated MCAO rat brains. Gal3 increased vessel density and neuronal survival after I/R in rat brains. Importantly, Gal3-treated groups showed significant improvement in motor and sensory functional recovery. Gal3 increased neuronal cell viability under in vitro oxygen-glucose deprivation conditions in association with increased phosphorylated-Akt, decreased phosphorylated-ERK1/2, and reduced caspase-3 activity. Gene expression analysis showed down regulation of pro-apoptotic and inflammatory genes including Fas-ligand, and upregulation of pro-survival and pro-angiogenic genes including Bcl-2, PECAM, and occludin. These results indicate a key role for Gal3 in neuro-vascular protection and functional recovery following ischemic stroke through modulation of angiogenic and apoptotic pathways.

Magnitude, risk factors and outcomes of stroke at Debre Markos Referral Hospital, Northwest Ethiopia: a retrospective observational study

Background

Stroke is one of the leading causes of death and disability in developing countries. The burden of stroke has varied widely in different areas, and there is a paucity of information about stroke in the selected study area.

Objectives

To assess the burden, risk factors, and outcomes of stroke at Debre Markos Referral Hospital, Northwest Ethiopia

Patients and methods

A hospital-based retrospective observational study was conducted in the medical ward of Debre Markos Referral Hospital from March 2017 to April 2019. A pretested checklist was used to extract relevant data from the chart of stroke patients. All statistical analyses were performed in the SPSS version 20 software.

Results

From a total of 2100 admissions in the medical ward, 162 of them were stroke patients, giving the in-hospital magnitude of 7.7%. The in-hospital case fatality rate was 8.6%. Additionally, 27.2% of patients were improved and 39.5% of them were referred. There was a significant association between types of stroke and risk factors such as sex, comorbid hypertension, hyperlipidemia, and atrial fibrillation (P ≤ 0.05).

Conclusion

The in-hospital period prevalence of stroke was 7.7%. Ischemic stroke was the most common type of stroke. Hypertension and hyperlipidemia were the leading identified risk factors for stroke. The overall in-hospital mortality was lower than previous studies in sub-Saharan African countries. Therefore, effective strategies and guidelines for the prevention and control of stroke and its risk factors are needed.