Alagebrium and Complications of Diabetes Mellitus

Pathological role of RAGE underlying progression of various diseases: its potential as biomarker and therapeutic target

The receptor for advanced glycation end products (RAGE) is a multi-ligand receptor with several structural types, performing a myriad of molecular mechanisms. The RAGE-ligand interactions play important roles in maintaining latent chronic inflammation, and oxidative damage underlying various pathological conditions like metabolic syndrome (MetS), neurodegenerative diseases, stroke, cardiovascular disorders, pulmonary disorders, cancer and infections. RAGE is thoroughly explored in knockout animals and human trials, targeted by small molecule inhibitors, peptides, diet, and natural compounds. But it is yet to be incorporated in the mainstream management of any ailment. This review performs an appraisal of the pathological mechanisms influenced by RAGE to uncover its prospects as a biomarker while also assessing its power to become a promising therapeutic target.

In vivo glycation-interplay between oxidant and carbonyl stress in bone

Metabolic syndromes (eg, obesity, type 2 diabetes (T2D), atherosclerosis, and neurodegenerative diseases) and aging, they all have a strong component of carbonyl and reductive-oxidative (redox) stress. Reactive carbonyl (RCS) and oxidant (ROS) stress species are commonly generated as products or byproducts of cellular metabolism or are derived from the environment. RCS and ROS can play a dual role in living organisms. Some RCS and ROS function as signaling molecules, which control cellular defenses against biological and environmental assaults. However, due to their high reactivity, RCS and ROS inadvertently interact with different cellular and extracellular components, which can lead to the formation of undesired posttranslational modifications of bone matrix proteins. These are advanced glycation (AGEs) and glycoxidation (AGOEs) end products generated in vivo by non-enzymatic amino-carbonyl reactions. In this review, metabolic processes involved in generation of AGEs and AGOEs within and on protein surfaces including extracellular bone matrix are discussed from the perspective of cellular metabolism and biochemistry of certain metabolic syndromes. The impact of AGEs and AGOEs on some characteristics of mineral is also discussed. Different therapeutic approaches with the potential to prevent the formation of RCS, ROS, and the resulting formation of AGEs and AGOEs driven by these chemicals are also briefly reviewed. These are antioxidants, scavenging agents of reactive species, and newly emerging technologies for the development of synthetic detoxifying systems. Further research in the area of in vivo glycation and glycoxidation should lead to the development of diverse new strategies for halting the progression of metabolic complications before irreversible damage to body tissues materializes.

A mathematical model of glomerular fibrosis in diabetic kidney disease to predict therapeutic efficacy

Background

Glomerular fibrosis is a tissue damage that occurs within the kidneys of chronic and diabetic kidney disease patients. Effective treatments are lacking, and the mechanism of glomerular damage reversal is poorly understood.

Methods

A mathematical model suitable for hypothesis-driven systems pharmacology of glomerular fibrosis in diabetes was developed from a previous model of interstitial fibrosis. The adapted model consists of a system of ordinary differential equations that models the complex disease etiology and progression of glomerular fibrosis in diabetes.

Results

Within the scope of the mechanism incorporated, advanced glycation end products (AGE)-matrix proteins that are modified due to high blood glucose-were identified as major contributors to the delay in the recovery from glomerular fibrosis after glucose control. The model predicted that inhibition of AGE production is not an effective approach for accelerating the recovery from glomerular fibrosis. Further, the model predicted that treatment breaking down accumulated AGE is the most productive at reversing glomerular fibrosis. The use of the model led to the identification that glucose control and aminoguanidine are ineffective treatments for reversing advanced glomerular fibrosis because they do not remove accumulated AGE. Additionally, using the model, a potential explanation was generated for the lack of efficacy of alagebrium in treating advanced glomerular fibrosis, which is due to the inability of alagebrium to reduce TGF- β .

Impact

Using the mathematical model, a mechanistic understanding of disease etiology and complexity of glomerular fibrosis in diabetes was illuminated, and then hypothesis-driven explanations for the lack of efficacy of different pharmacological agents for treating glomerular fibrosis were provided. This understanding can enable the development of more efficacious therapeutics for treating kidney damage in diabetes.

Directed Design, Screening and Antiglycation Activity for 3-Substituted Thiazolium Derivatives, New Analogs of Alagebrium

Preliminary ab initio calculations led to the synthesis of novel substituted thiazolium salts, analogs of Alagebrium, which were further explored in vitro for their potential as inhibitors of the glycation reaction utilizing three distinct assays: inhibition of fluorescent AGEs formation, anticrosslinking, and deglycation. Despite the unidirectionality of the assays, distinct differences were observed in the mechanisms of interference and activity manifestation by the compounds. The gathered data permitted the formation of hypotheses about the molecular fragments of the studied antiglycators that are of utmost significance in each assay, thereby guiding future design endeavors. Potential mechanisms of actions are discussed therein. The compound 4-meth-yl-3-[2-(4-methylbiphenyl-4-yl)-2-oxoethyl] thiazolium bromide displayed high activity across all three assays, establishing it as a lead compound. The cytotoxicological properties of the compounds were evaluated using LDH and MTT assays. However, the lead compound exhibited cytotoxicity, indicating the need for additional investigations aimed at decreasing toxicity while maintaining activity. The targeted thiazolium salts were synthesized through an N-alkylation reaction between the corresponding thiazoles and phenacyl bromides.

Pivotal role of AGE-RAGE axis in brain aging with current interventions

Brain aging is characterized by several structural, biochemical and molecular changes which can vary among different individuals and can be influenced by genetic, environmental and lifestyle factors. Accumulation of protein aggregates, altered neurotransmitter composition, low-grade chronic inflammation and prolonged oxidative stress have been shown to contribute to brain tissue damage. Among key metabolic byproducts, advanced glycation end products (AGEs), formed endogenously through non-enzymatic reactions or acquired directly from the diet or other exogenous sources, have been detected to accumulate in brain tissue, exerting detrimental effects on cellular structure and function, contributing to neurodegeneration and cognitive decline. Upon binding to signal transduction receptor RAGE, AGEs can initiate pro-inflammatory pathways, exacerbate oxidative stress and neuroinflammation, thus impairing neuronal function and cognition. AGE-RAGE signaling induces programmed cell death, disrupts the blood-brain barrier and promotes protein aggregation, further compromising brain health. In this review, we investigate the intricate relationship between the AGE-RAGE pathway and brain aging in order to detect affected molecules and potential targets for intervention. Reduction of AGE deposition in brain tissue either through novel pharmacological therapeutics, dietary modifications, and lifestyle changes, shows a great promise in mitigating cognitive decline associated with brain aging.

Decoding the role of aldosterone in glycation-induced diabetic complications

Diabetes-mediated development of micro and macro-vascular complications is a global concern. One of the factors is hyperglycemia induced the non-enzymatic formation of advanced glycation end products (AGEs). Accumulated AGEs bind with receptor of AGEs (RAGE) causing inflammation, oxidative stress and extracellular matrix proteins (ECM) modifications responsible for fibrosis, cell damage and tissue remodeling. Moreover, during hyperglycemia, aldosterone (Aldo) secretion increases, and its interaction with mineralocorticoid receptor (MR) through genomic and non-genomic pathways leads to inflammation and fibrosis. Extensive research on individual involvement of AGEs-RAGE and Aldo-MR pathways in the development of diabetic nephropathy (DN), cardiovascular diseases (CVDs), and impaired immune system has led to the discovery of therapeutic drugs. Despite mutual repercussions, the cross-talk between AGEs-RAGE and Aldo-MR pathways remains unresolved. Hence, this review focuses on the possible interaction of Aldo and glycation in DN and CVDs, considering the clinical significance of mutual molecular targets.

Activation and modulation of the AGEs-RAGE axis: Implications for inflammatory pathologies and therapeutic interventions - A review

Chronic inflammation is a common foundation for the development of many non-communicable diseases, particularly diabetes, atherosclerosis, and tumors. The activation of the axis involving Advanced Glycation End products (AGEs) and their receptor RAGE is a key promotive factor in the chronic inflammation process, influencing the pathological progression of these diseases. The accumulation of AGEs in the body results from an increase in glycation reactions and oxidative stress, especially pronounced in individuals with diabetes. By binding to RAGE, AGEs activate signaling pathways such as NF-κB, promoting the release of inflammatory factors, exacerbating cell damage and inflammation, and further advancing the formation of atherosclerotic plaques and tumor development. This review will delve into the molecular mechanisms by which the AGEs-RAGE axis activates chronic inflammation in the aforementioned diseases, as well as strategies to inhibit the AGEs-RAGE axis, aiming to slow or halt the progression of chronic inflammation and related diseases. This includes the development of AGEs inhibitors, RAGE antagonists, and interventions targeting upstream and downstream signaling pathways. Additionally, the early detection of AGEs levels and RAGE expression as biomarkers provides new avenues for the prevention and treatment of diabetes, atherosclerosis, and tumors.

Glycation in the cardiomyocyte

Glycation is a protein post-translational modification that can occur on lysine and arginine residues as a result of a non-enzymatic process known as the Maillard reaction. This modification is irreversible, so the only way it can be removed is by protein degradation and replacement. Small reactive carbonyl species, glyoxal and methylglyoxal, are the primary glycating agents and are elevated in several conditions associated with an increased risk of cardiovascular disease, including diabetes, rheumatoid arthritis, smoking, and aging. Thus, how protein glycation impacts the cardiomyocyte is of particular interest, to both understand how these conditions increase the risk of cardiovascular disease and how glycation might be targeted therapeutically. Glycation can affect the cardiomyocyte through extracellular mechanisms, including RAGE-based signaling, glycation of the extracellular matrix that modifies the mechanical environment, and signaling from the vasculature. Intracellular glycation of the cardiomyocyte can impact calcium handling, protein quality control and cell death pathways, as well as the cytoskeleton, resulting in a blunted contractility. While reducing protein glycation and its impact on the heart has been an active area of drug development, multiple clinical trials have had mixed results and these compounds have not been translated to the clinic-highlighting the challenges of modulating myocyte glycation. Here we will review protein glycation and its effects on the cardiomyocyte, therapeutic attempts to reverse these, and offer insight as to the future of glycation studies and patient treatment.

(+)-Catechin mitigates impairment in insulin secretion and beta cell damage in methylglyoxal-induced pancreatic beta cells

BACKGROUND

The formation of advanced glycation end products (AGEs) is the central process contributing to diabetic complications in diabetic individuals with sustained and inconsistent hyperglycemia. Methylglyoxal, a reactive carbonyl species, is found to be a major precursor of AGEs, and its levels are elevated in diabetic conditions. Dysfunction of pancreatic beta cells and impairment in insulin secretion are the hallmarks of diabetic progression. Exposure to methylglyoxal-induced AGEs alters the function and maintenance of pancreatic beta cells. Hence, trapping methylglyoxal could be an ideal approach to alleviate AGE formation and its influence on beta cell proliferation and insulin secretion, thereby curbing the progression of diabetes to its complications.

METHODS AND RESULTS

In the present study, we have explored the mechanism of action of (+)-Catechin against methylglyoxal-induced disruption in pancreatic beta cells via molecular biology techniques, mainly western blot. Methylglyoxal treatment decreased insulin synthesis (41.5%) via downregulating the glucose-stimulated insulin secretion pathway (GSIS). This was restored upon co-treatment with (+)-Catechin (29.9%) in methylglyoxal-induced Beta-TC-6 cells. Also, methylglyoxal treatment affected the autocrine function of insulin by disrupting the IRS1/PI3k/Akt pathway. Methylglyoxal treatment suppresses Pdx-1 and Maf A levels, which are responsible for beta cell maintenance and cell proliferation. (+)-Catechin could significantly augment the levels of these transcription factors.

CONCLUSION

This is the first study to examine the impact of a natural compound on methylglyoxal with the insulin-mediated autocrine and paracrine activities of pancreatic beta cells. The results indicate that (+)-Catechin exerts a protective effect against methylglyoxal exposure in pancreatic beta cells and can be considered a potential anti-glycation agent in further investigations on ameliorating diabetic complications.

The cardiovascular changes underlying a low cardiac output with exercise in patients with type 2 diabetes mellitus

The significant morbidity and premature mortality of type 2 diabetes mellitus (T2DM) is largely associated with its cardiovascular consequences. Focus has long been on the arterial atheromatosis of DM giving rise to early stroke and myocardial infarctions, whereas less attention has been given to its non-ischemic cardiovascular consequences. Irrespective of ischemic changes, T2DM is associated with heart failure (HF) most commonly with preserved ejection fraction (HFpEF). Largely due to increasing population ages, hypertension, obesity and T2DM, HFpEF is becoming the most prevalent form of heart failure. Unfortunately, randomized controlled trials of HFpEF have largely been futile, and it now seems logical to address the important different phenotypes of HFpEF to understand their underlying pathophysiology. In the early phases, HFpEF is associated with a significantly impaired ability to increase cardiac output with exercise. The lowered cardiac output with exercise results from both cardiac and peripheral causes. T2DM is associated with left ventricular (LV) diastolic dysfunction based on LV hypertrophy with myocardial disperse fibrosis and significantly impaired ability for myocardial blood flow increments with exercise. T2DM is also associated with impaired ability for skeletal muscle vasodilation during exercise, and as is the case in the myocardium, such changes may be related to vascular rarefaction. The present review discusses the underlying phenotypical changes of the heart and peripheral vascular system and their importance for an adequate increase in cardiac output. Since many of the described cardiovascular changes with T2DM must be considered difficult to change if fully developed, it is suggested that patients with T2DM are early evaluated with respect to their cardiovascular compromise.

Effect of advanced glycation end-products in a wide range of medical problems including COVID-19

Glycation is a physiological process that determines the aging of the organism, while in states of metabolic disorders it is significantly intensified. High concentrations of compounds such as reducing sugars or reactive aldehydes derived from lipid oxidation, occurring for example in diabetes, atherosclerosis, dyslipidemia, obesity or metabolic syndrome, lead to increased glycation of proteins, lipids and nucleic acids. The level of advanced glycation end-products (AGEs) in the body depends on rapidity of their production and the rate of their removal by the urinary system. AGEs, accumulated in the extracellular matrix of the blood vessels and other organs, cause irreversible changes in the biochemical and biomechanical properties of tissues. As a consequence, micro- and macroangiopathies appear in the system, and may contribute to the organ failure, like kidneys and heart. Elevated levels of AGEs also increase the risk of Alzheimer's disease and various cancers. In this paper, we propose a new classification due to modified amino acid residues: arginyl-AGEs, monolysyl-AGEs and lysyl-arginyl-AGEs and dilysyl-AGEs. Furthermore, we describe in detail the effect of AGEs on the pathogenesis of metabolic and old age diseases, such as diabetic complications, atherosclerosis and neurodegenerative diseases. We summarize the currently available data on the diagnostic value of AGEs and present the AGEs as a therapeutic goal in a wide range of medical problems, including SARS-CoV-2 infection and so-called long COVID.

Emerging green synthetic routes for thiazole and its derivatives: Current perspectives

This review article provides an overview of the green synthesis of thiazole derivatives, emphasizing sustainable and environmentally friendly methodologies. Thiazole derivatives possess significant value and find diverse applications across various fields. However, conventional synthesis methods often involve hazardous reagents and generate substantial waste, posing environmental concerns. The green synthesis of thiazole derivatives employs renewable starting materials, nontoxic catalysts, and mild reaction conditions to minimize environmental impact. Innovative techniques such as microwave irradiation, ultrasound synthesis, green solvents, a green catalyst-based approach, and mechanochemistry-mediated synthesis are employed, offering advantages in terms of scalability, cost-effectiveness, and purification simplicity. The resulting thiazole derivatives exhibit comparable or enhanced biological activities, showcasing the feasibility and practicality of green synthesis in drug discovery. This review paper underscores the importance of sustainable approaches in functional molecular synthesis and encourages further research in this domain.

Nε-(1-Carboxymethyl)-L-lysine/RAGE Signaling Drives Metastasis and Cancer Stemness through ERK/NFκB axis in Osteosarcoma

Osteosarcoma is an extremely aggressive bone cancer with poor prognosis. Nε-(1-Carboxymethyl)-L-lysine (CML), an advanced glycation end product (AGE), can link to cancer progression, tumorigenesis and metastasis, although the underlying mechanism remains unclear. The role of CML in osteosarcoma progression is still unclear. We hypothesized that CML could promote migration, invasion, and stemness in osteosarcoma cells. CML and its receptor (RAGE; receptor for AGE) were higher expressed at advanced stages in human osteosarcoma tissues. In mouse models, which streptozotocin was administered to induce CML accumulation in the body, the subcutaneous tumor growth was not affected, but the tumor metastasis using tail vein injection model was enhanced. In cell models (MG63 and U2OS cells), CML enhanced tumor sphere formation and acquisition of cancer stem cell characteristics, induced migration and invasion abilities, as well as triggered the epithelial-mesenchymal transition process, which were associated with RAGE expression and activation of downstream signaling pathways, especially the ERK/NFκB pathway. RAGE inhibition elicited CML-induced cell migration, invasion, and stemness through RAGE-mediated ERK/NFκB pathway. These results revealed a crucial role for CML in driving stemness and metastasis in osteosarcoma. These findings uncover a potential CML/RAGE connection and mechanism to osteosarcoma progression and set the stage for further investigation.

Synthesis and antiglycation activity of 3-phenacyl substituted thiazolium salts, new analogs of Alagebrium

After preliminary ab initio calculations, 3-phenacyl substituted thiazolium salts, analogs of Alagebrium, were synthesized and investigated in vitro as glycation reaction inhibitors. The most part of investigations focused on the potential of the title compounds to attenuate the formation of fluorescent AGEs as well on their ability to disrupt the cross-linking formation among glycated proteins. Additionally, the capability of thiazolium salts to deglycate in the reaction of early glycation products with nitroblue tetrazolium was determined. Cytotoxicological properties of the title compounds were evaluated using LDH and MTT assays. The leader compound (3-[2-(biphenyl-4-yl)-2-oxoethyl]-1,3-thiazol-3-ium bromide) in a 50 mg/kg dose (p.o. 14 days) was further tested within an in vivo carbonyl stress model (rats, methylglyoxal 86.25 mg/kg/d, i.p., 14 days). As a result, the leader-molecule revealed a high effectiveness against all three examined mechanisms of glycation reaction inhibition in in vitro tests and was able to suppress capacity of methylglyoxal to form AGEs in vivo.

Receptor for advanced glycation end-products: Biological significance and imaging applications

The receptor for advanced glycation end-products (RAGE or AGER) is a transmembrane, immunoglobulin-like receptor that, due to its multiple isoform structures, binds to a diverse range of endo- and exogenous ligands. RAGE activation caused by the ligand binding initiates a cascade of complex pathways associated with producing free radicals, such as reactive nitric oxide and oxygen species, cell proliferation, and immunoinflammatory processes. The involvement of RAGE in the pathogenesis of disorders such as diabetes, inflammation, tumor progression, and endothelial dysfunction is dictated by the accumulation of advanced glycation end-products (AGEs) at pathologic states leading to sustained RAGE upregulation. The involvement of RAGE and its ligands in numerous pathologies and diseases makes RAGE an interesting target for therapy focused on the modulation of both RAGE expression or activation and the production or exogenous administration of AGEs. Despite the known role that the RAGE/AGE axis plays in multiple disease states, there remains an urgent need to develop noninvasive, molecular imaging approaches that can accurately quantify RAGE levels in vivo that will aid in the validation of RAGE and its ligands as biomarkers and therapeutic targets. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Diagnostic Tools > Biosensing.

Pharmacological modulation of vascular ageing: A review from VascAgeNet

Vascular ageing, characterized by structural and functional changes in blood vessels of which arterial stiffness and endothelial dysfunction are key components, is associated with increased risk of cardiovascular and other age-related diseases. As the global population continues to age, understanding the underlying mechanisms and developing effective therapeutic interventions to mitigate vascular ageing becomes crucial for improving cardiovascular health outcomes. Therefore, this review provides an overview of the current knowledge on pharmacological modulation of vascular ageing, highlighting key strategies and promising therapeutic targets. Several molecular pathways have been identified as central players in vascular ageing, including oxidative stress and inflammation, the renin-angiotensin-aldosterone system, cellular senescence, macroautophagy, extracellular matrix remodelling, calcification, and gasotransmitter-related signalling. Pharmacological and dietary interventions targeting these pathways have shown potential in ameliorating age-related vascular changes. Nevertheless, the development and application of drugs targeting vascular ageing is complicated by various inherent challenges and limitations, such as certain preclinical methodological considerations, interactions with exercise training and sex/gender-related differences, which should be taken into account. Overall, pharmacological modulation of endothelial dysfunction and arterial stiffness as hallmarks of vascular ageing, holds great promise for improving cardiovascular health in the ageing population. Nonetheless, further research is needed to fully elucidate the underlying mechanisms and optimize the efficacy and safety of these interventions for clinical translation.

Methylglyoxal in Cardiometabolic Disorders: Routes Leading to Pathology Counterbalanced by Treatment Strategies

Methylglyoxal (MGO) is the major compound belonging to reactive carbonyl species (RCS) responsible for the generation of advanced glycation end products (AGEs). Its upregulation, followed by deleterious effects at the cellular and systemic levels, is associated with metabolic disturbances (hyperglycemia/hyperinsulinemia/insulin resistance/hyperlipidemia/inflammatory processes/carbonyl stress/oxidative stress/hypoxia). Therefore, it is implicated in a variety of disorders, including metabolic syndrome, diabetes mellitus, and cardiovascular diseases. In this review, an interplay between pathways leading to MGO generation and scavenging is addressed in regard to this system's impairment in pathology. The issues associated with mechanistic MGO involvement in pathological processes, as well as the discussion on its possible causative role in cardiometabolic diseases, are enclosed. Finally, the main strategies aimed at MGO and its AGEs downregulation with respect to cardiometabolic disorders treatment are addressed. Potential glycation inhibitors and MGO scavengers are discussed, as well as the mechanisms of their action.

Repurposing alagebrium for diabetic foot ulcer healing: Impact on AGEs/NFκB/NOX1 signaling

BACKGROUND

Diabetic foot ulcer (DFU) is a common diabetic complication associated with disability and reduced quality of life. Available therapeutics are not sufficient to combat the spread of DFU. Here we aim to investigate the impact of alagebrium, an advanced glycation end product (AGE)-crosslink breaker, on the healing of DFU.

METHODS

Diabetes was induced in Wistar rats by STZ, and after four weeks, wound was induced on the foot. Alagebrium (10 mg/kg) was administered orally for 14 days, and wound size was measured every 3 days. Behavioral tests i.e., hot plate and footprint tests, were performed to assess sensory function and gait. Blood was collected to assess HbA1c, serum AGEs, MDA and NOX1. Tissue was collected to assess histological changes and expression of NF-κB, iNOS, TNF-α, VEGF and EGF. In a subsequent set of experiments with similar design, alagebrium was applied topically as a film-forming gel.

RESULTS

Systemic alagebrium treatment accelerated the healing of diabetic wound, improved sensory functions and gait, and ameliorated histological changes. It also reduced serum levels of AGEs, MDA and NOX1, and the tissue expression of NF-κB, iNOS, TNF-α, and increased VEGF and EGF in diabetic rats. Topical alagebrium led to similar beneficial effects i.e., accelerated diabetic wound healing, improved wound histological changes, reduced expression of NF-κB and iNOS and increased VEGF.

CONCLUSIONS

Our findings suggest repurposing of alagebrium for the management of DFU to accelerate the healing process and improve the clinical outcomes in diabetic patients.

Evidence that methylglyoxal and receptor for advanced glycation end products are implicated in bladder dysfunction of obese diabetic ob/ob mice

Glycolytic overload in diabetes causes large accumulation of the highly reactive dicarbonyl compound methylglyoxal (MGO) and overproduction of advanced glycation end products (AGEs), which interact with their receptors (RAGE), leading to diabetes-associated macrovascular complications. The bladder is an organ that stays most in contact with dicarbonyl species, but little is known about the importance of the MGO-AGEs-RAGE pathway to diabetes-associated bladder dysfunction. Here, we aimed to investigate the role of the MGO-AGEs-RAGE pathway in bladder dysfunction of diabetic male and female ob/ob mice compared with wild-type (WT) lean mice. Diabetic ob/ob mice were treated with the AGE breaker alagebrium (ALT-711, 1 mg/kg) for 8 wk in drinking water. Compared with WT animals, male and female ob/ob mice showed marked hyperglycemia and insulin resistance, whereas fluid intake remained unaltered. Levels of total AGEs, MGO-derived hydroimidazolone 1, and RAGE in bladder tissues, as well as fluorescent AGEs in serum, were significantly elevated in ob/ob mice of either sex. Collagen content was also markedly elevated in the bladders of ob/ob mice. Void spot assays in filter paper in conscious mice revealed significant increases in total void volume and volume per void in ob/ob mice with no alterations of spot number. Treatment with ALT-711 significantly reduced the levels of MGO, AGEs, RAGE, and collagen content in ob/ob mice. In addition, ALT-711 treatment normalized the volume per void and increased the number of spots in ob/ob mice. Activation of AGEs-RAGE pathways by MGO in the bladder wall may contribute to the pathogenesis of diabetes-associated bladder dysfunction.NEW & NOTEWORTHY The involvement of methylglyoxal (MGO) and advanced glycation end products (AGEs) in bladder dysfunction of diabetic ob/ob mice treated with the AGE breaker ALT-711 was investigated here. Diabetic mice exhibited high levels of MGO, AGEs, receptor for AGEs (RAGE), and collagen in serum and/or bladder tissues along with increased volume per void, all of which were reduced by ALT-711. Activation of the MGO-AGEs-RAGE pathway in the bladder wall contributes to the pathogenesis of diabetes-associated bladder dysfunction.

Synthesis of hydrazinylthiazole carboxylates: a mechanistic approach for treatment of diabetes and its complications

Aim: The deaths of thousands of people and millions affected by diabetes mellitus triggered us to look for alternative possible solutions to cure diabetes and its complications. Materials & methods: A series of hydrazinylthiazole carboxylates (3a-n) was prepared by cyclocondensation reaction of thiosemicarbazones with ethyl 2-chloroacetoacetate. These compounds were screened for antidiabetic potential through α-amylase inhibition, antiglycation and antioxidant assays. Results & conclusion: Most of the compounds exhibited a promising antidiabetic property. Compounds 3e and 3h showed excellent α-amylase and glycation inhibition properties. The hemolytic assay indicated that all compounds are biocompatible. Docking studies carried out on α-amylase target showed correlation between in vitro inhibition and binding energy.

Signaling pathways in vascular function and hypertension: molecular mechanisms and therapeutic interventions

Hypertension is a global public health issue and the leading cause of premature death in humans. Despite more than a century of research, hypertension remains difficult to cure due to its complex mechanisms involving multiple interactive factors and our limited understanding of it. Hypertension is a condition that is named after its clinical features. Vascular function is a factor that affects blood pressure directly, and it is a main strategy for clinically controlling BP to regulate constriction/relaxation function of blood vessels. Vascular elasticity, caliber, and reactivity are all characteristic indicators reflecting vascular function. Blood vessels are composed of three distinct layers, out of which the endothelial cells in intima and the smooth muscle cells in media are the main performers of vascular function. The alterations in signaling pathways in these cells are the key molecular mechanisms underlying vascular dysfunction and hypertension development. In this manuscript, we will comprehensively review the signaling pathways involved in vascular function regulation and hypertension progression, including calcium pathway, NO-NOsGC-cGMP pathway, various vascular remodeling pathways and some important upstream pathways such as renin-angiotensin-aldosterone system, oxidative stress-related signaling pathway, immunity/inflammation pathway, etc. Meanwhile, we will also summarize the treatment methods of hypertension that targets vascular function regulation and discuss the possibility of these signaling pathways being applied to clinical work.

DF-5 COMPOUND DELAYS DEVELOPMENT OF DIABETIC NEPHROPATHY IN RATS

Advanced glycation end-products play an important role in the development of diabetic complications, so slowing down of glycated proteins’ cross-links formation have been suggested as a potential therapeutic option for the treatment of vascular diabetic complications and preventing their progression.

The aim of the work was to assess the influence of novel anticrosslinking agent DF-5 on the renal advanced glycation end-products and collagen contents, body weight, blood glucose and glycated hemoglobin levels and the development of early renal disease in streptozotocin-induced diabetic rats.

Materials and methods. 40 male Sprague-Dawley rats were used in the study. Two months after inducing diabetes, the study substance was administered intragastrically once a day for 28 days (12.5 mg/kg). Measurements included the assessment of blood glucose and HbA1c levels, the evaluation of the renal function, and the results of histology and immunohistochemical staining of kidneys.

Results. A repeated intragastric administration of DF-5 for 30 days significantly reduced the level of HbA1c in the blood, but did not affect the level of fasting blood glucose. DF-5 compound significantly reduced proteinuria and prevented kidney damage in experimental animals by limiting damage of the glomeruli and tubules. It was found that DF-5 inhibits the progression of an early renal dysfunction in rats with streptozotocin-induced diabetic nephropathy. This was associated with a decreased accumulation of advanced glycation end-products in the kidney, accompanied by the improvement of both renal morphology and function.

Conclusion. The results obtained provide investigators with additional therapeutic options for the treatment of diabetic nephropathy and possibly other complications of diabetes.

Advanced Glycation End-Products and Diabetic Neuropathy of the Retina

Diabetic retinopathy is a tissue-specific neurovascular impairment of the retina in patients with both type 1 and type 2 diabetes. Several pathological factors are involved in the progressive impairment of the interdependence between cells that consist of the neurovascular units (NVUs). The advanced glycation end-products (AGEs) are one of the major pathological factors that cause the impairments of neurovascular coupling in diabetic retinopathy. Although the exact mechanisms for the toxicities of the AGEs in diabetic retinopathy have not been definitively determined, the AGE-receptor of the AGE (RAGE) axis, production of reactive oxygen species, inflammatory reactions, and the activation of the cell death pathways are associated with the impairment of the NVUs in diabetic retinopathy. More specifically, neuronal cell death is an irreversible change that is directly associated with vision reduction in diabetic patients. Thus, neuroprotective therapies must be established for diabetic retinopathy. The AGEs are one of the therapeutic targets to examine to ameliorate the pathological changes in the NVUs in diabetic retinopathy. This review focuses on the basic and pathological findings of AGE-induced neurovascular abnormalities and the potential therapeutic approaches, including the use of anti-glycated drugs to protect the AGE-induced impairments of the NVUs in diabetic retinopathy.

Emerging targets for cancer treatment: S100A9/RAGE

Developing better treatments that work for the majority of patients with brain metastasis (BM) is highly necessary. Complementarily, avoiding those therapeutic procedures that will not benefit a specific patient is also very relevant. In general, existing therapies for patients with BM could be improved in terms of molecular stratification and therapeutic efficacy. By questioning the benefit of whole brain radiotherapy as provided nowadays and the lack of biomarkers detecting radioresistance, we identified S100A9 and receptor for advanced glycation end-products (RAGE) as a liquid biopsy biomarker and a potential target for a radiosensitizer, respectively. Both of them are being clinically tested as part of the first comprehensive molecular strategy to personalized radiotherapy in BM.

Large vessel occlusion stroke outcomes in diabetic vs. non-diabetic patients with acute stress hyperglycemia

Objective

This study assesses whether stress-induced hyperglycemia is a predictor of poor outcome at 3 months for patients with acute ischemic stroke (AIS) treated by endovascular treatment (EVT) and impacted by their previous blood glucose status.

Methods

This retrospective study collected data from 576 patients with AIS due to large vessel occlusion (LVO) treated by EVT from March 2019 to June 2022. The sample was composed of 230 and 346 patients with and without diabetes mellitus (DM), respectively, based on their premorbid diabetic status. Prognosis was assessed with modified Rankin Scale (mRS) at 3-month after AIS. Poor prognosis was defined as mRS>2. Stress-induced hyperglycemia was assessed by fasting glucose-to-glycated hemoglobin ratio (GAR). Each group was stratified into four groups by quartiles of GAR (Q1-Q4). Binary logistic regression analysis was used to identify relationship between different GAR quartiles and clinical outcome after EVT.

Results

In DM group, a poor prognosis was seen in 122 (53%) patients and GAR level was 1.27 ± 0.44. These variables were higher than non-DM group and the differences were statistically significant (p < 0.05, respectively). Patients with severe stress-induced hyperglycemia demonstrated greater incidence of 3-month poor prognosis (DM: Q1, 39.7%; Q2, 45.6%; Q3, 58.6%; Q4, 68.4%; p = 0.009. Non-DM: Q1, 31%; Q2, 32.6%; Q3, 42.5%; Q4, 64%; p < 0.001). However, the highest quartile of GAR was independently associated with poor prognosis at 3 months (OR 3.39, 95% CI 1.66-6.96, p = 0.001), compared to the lowest quartile in non-DM patients after logistic regression. This association was not observed from DM patients.

Conclusion

The outcome of patients with acute LVO stroke treated with EVT appears to be influenced by premorbid diabetes status. However, the poor prognosis at 3-month in patients with DM is not independently correlated with stress-induced hyperglycemia. This could be due to the long-term damage of persistent hyperglycemia and diabetic patients' adaptive response to stress following acute ischemic damage to the brain.

Glycation of LDL: AGEs, impact on lipoprotein function, and involvement in atherosclerosis

Atherosclerosis is a complex disease, and there are many factors that influence its development and the course of the disease. A deep understanding of the pathological mechanisms underlying atherogenesis is needed to develop optimal therapeutic strategies and treatments. In this review, we have focused on low density lipoproteins. According to multiple studies, their atherogenic properties are associated with multiple modifications of lipid particles. One of these modifications is Glycation. We considered aspects related to the formation of modified particles, as well as the influence of modification on their functioning. We paid special attention to atherogenicity and the role of glycated low-density lipoprotein (LDL) in atherosclerosis.

The influence of UV irradiation on fish skin collagen films in the presence of xanthohumol and propanediol

Fish skin collagen films are widely used as adhesives in medicine and cosmetology. Ultraviolet (UV) irradiation can be considered as an effective sterilization method for biomaterials, however, it may also lead to material photodegradation. In this work, the influence of xanthohumol and propanediol on the physico-chemical properties of collagen films before and after UV irradiation was studied. Collagen for this research was extracted from silver carp skin and thin films were fabricated by the solution casting methods. The structure of films was researched using infrared spectroscopy. The surface properties of films were investigated using Atomic Force Microscopy (AFM) and contact angle measurements. Mechanical properties were measured as well. It was found that the addition of xanthohumol and propanediol modified the roughness of collagen films and their mechanical properties. UV irradiation led to the water loss from the film and modification of the collagen structure. In the presence of propanediol and xanthohumol the water loss after UV irradiation was smaller than in UV-irradiated collagen films without these additives.

AGE-breaker ALT711 reverses glycation-mediated cancer cell migration

Diabetes is associated with increased risk of breast cancer and worse prognoses for cancer patients. Hyperglycemia can result in increased glycation, the process wherein crosslinkages are formed between sugars and extracellular matrix (ECM) proteins through the formation of advanced glycation endproducts (AGEs). Although accumulation of AGEs occurs naturally in vivo over time, it is greatly accelerated by the hyperglycemic environment of diabetic patients. AGE accumulation has been linked to stiffening-related diseases such as hypertension, cancer metastasis, and neurodegenerative disorders. In response, several AGE-inhibiting and AGE-breaking drugs have received significant attention for their ability to reduce AGE accumulation. The resulting effects of these drugs on cell behavior is not well understood. In this study, we measured cancer cell migration in glycated collagen with and without the AGE-breaking drug alagebrium chloride (ALT711) to investigate the drug's ability to disrupt ECM crosslinks and reduce tumor cell spreading, contractility, and migration. The mechanical properties and chemical composition of collagen glycated with increasing concentrations of glucose with and without ALT711 treatment were measured. Increasing glucose concentration resulted in increased AGE accumulation and matrix stiffness as well as increased cancer cell contractility, elongation, and migration. Treatment with ALT711 significantly lowered AGE accumulation within the collagen, decreased collagen stiffness, and reduced cell migration. These findings suggest that while hyperglycemia can increase collagen matrix stiffness, resulting in increased breast cancer cell migration, an AGE-breaker can reverse this phenotype and may be a viable treatment option for reducing cancer cell migration due to glycation.

Methylglyoxal and Its Adducts: Induction, Repair, and Association with Disease

Metabolism is an essential part of life that provides energy for cell growth. During metabolic flux, reactive electrophiles are produced that covalently modify macromolecules, leading to detrimental cellular effects. Methylglyoxal (MG) is an abundant electrophile formed from lipid, protein, and glucose metabolism at intracellular levels of 1-4 μM. MG covalently modifies DNA, RNA, and protein, forming advanced glycation end products (MG-AGEs). MG and MG-AGEs are associated with the onset and progression of many pathologies including diabetes, cancer, and liver and kidney disease. Regulating MG and MG-AGEs is a potential strategy to prevent disease, and they may also have utility as biomarkers to predict disease risk, onset, and progression. Here, we review recent advances and knowledge surrounding MG, including its production and elimination, mechanisms of MG-AGEs formation, the physiological impact of MG and MG-AGEs in disease onset and progression, and the latter in the context of its receptor RAGE. We also discuss methods for measuring MG and MG-AGEs and their clinical application as prognostic biomarkers to allow for early detection and intervention prior to disease onset. Finally, we consider relevant clinical applications and current therapeutic strategies aimed at targeting MG, MG-AGEs, and RAGE to ultimately improve patient outcomes.

Advanced Glycation End Products in Health and Disease

Advanced glycation end products (AGEs), formed through the nonenzymatic reaction of reducing sugars with the side-chain amino groups of lysine or arginine of proteins, followed by further glycoxidation reactions under oxidative stress conditions, are involved in the onset and exacerbation of a variety of diseases, including diabetes, atherosclerosis, and Alzheimer’s disease (AD) as well as in the secondary stages of traumatic brain injury (TBI). AGEs, in the form of intra- and interprotein crosslinks, deactivate various enzymes, exacerbating disease progression. The interactions of AGEs with the receptors for the AGEs (RAGE) also result in further downstream inflammatory cascade events. The overexpression of RAGE and the AGE-RAGE interactions are especially involved in cases of Alzheimer’s disease and other neurodegenerative diseases, including TBI and amyotrophic lateral sclerosis (ALS). Maillard reactions are also observed in the gut bacterial species. The protein aggregates found in the bacterial species resemble those of AD and Parkinson’s disease (PD), and AGE inhibitors increase the life span of the bacteria. Dietary AGEs alter the gut microbiota composition and elevate plasma glycosylation, thereby leading to systemic proinflammatory effects and endothelial dysfunction. There is emerging interest in developing AGE inhibitor and AGE breaker compounds to treat AGE-mediated pathologies, including diabetes and neurodegenerative diseases. Gut-microbiota-derived enzymes may also function as AGE-breaker biocatalysts. Thus, AGEs have a prominent role in the pathogenesis of various diseases, and the AGE inhibitor and AGE breaker approach may lead to novel therapeutic candidates.

The association between advanced glycation end products (AGEs) and ABC (hemoglobin A1C, blood pressure, and low-density lipoprotein cholesterol) control parameters among patients with type 2 diabetes mellitus

BACKGROUND

Diabetes-induced chronic hyperglycemia results in the formation and aggregation of advanced glycation end-products (AGEs), which are products of non-enzymatic glycosylation of lipids or proteins. The development of diabetic complications can be accelerated by AGEs. In the current study, we aimed to explore the relationship between AGEs levels and ABC goals of diabetes control (A: Hemoglobin A1C < 7.0%, B: Blood pressure < 140/90 mmHg, and C: low-density lipoprotein cholesterol [LDL] < 100 mg/dL).

METHODS

In the current cross-sectional study, 293 patients with type 2 diabetes mellitus (T2D), were enrolled. Demographic and clinical characteristics of the individuals were collected. AGEs levels were measured using quantitative fluorescence spectroscopy. Finally, the association of AGEs levels with patients' characteristics and ABC goals was assessed.

RESULTS

Higher serum AGEs concentration was detected in older age, smoking patients and those with higher diastolic blood pressure, lower high-density lipoprotein (HDL) level, lower body mass index (BMI) and retinopathy. Moreover, the T2D patients who achieved higher numbers of ABC goals of diabetes were younger age (P-value = 0.003), with lower hemoglobin A1C (P-value = 0.001), fasting blood sugar (P-value = 0.002) diastolic blood pressure (P-value = 0.001), systolic blood pressure (P-value = 0.001), cholesterol (P-value = 0.001), LDL (P-value = 0.001), and AGEs (P-value = 0.023) levels. Diabetic patients with AGEs levels above 73.9% were about 2.2 times more likely to achieve none of ABC treatment goals (95% CI 1.107-3.616).

CONCLUSION

Our results revealed the relationship between AGEs and ABC goal achievement, and microvascular diabetic complications, and imply that AGEs measurement may be valuable in the monitoring of diabetic patients' complications and treatment adjustment.

Avenues for post-translational protein modification prevention and therapy

Non-enzymatic post-translational modifications (nPTMs) of proteins have emerged as novel risk factors for the genesis and progression of various diseases. We now have a variety of experimental and established therapeutic strategies to target harmful nPTMs and potentially improve clinical outcomes. Protein carbamylation and glycation are two common and representative nPTMs that have gained considerable attention lately as favorable therapeutic targets with emerging clinical evidence. Protein carbamylation is associated with the occurrence of cardiovascular disease (CVD) and mortality in patients with chronic kidney disease (CKD); and advanced glycation end products (AGEs), a heterogeneous group of molecules produced in a series of glycation reactions, have been linked to various diabetic complications. Therefore, reducing the burden of protein carbamylation and AGEs is an appealing and promising therapeutic approach. This review chapter summarizes potential anti-nPTM therapy options in CKD, CVD, and diabetes along with clinical implications. Using two prime examples-protein carbamylation and AGEs-we discuss the varied preventative and therapeutic options to mitigate these pathologic nPTMs in detail. We provide in-depth case studies on carbamylation in the setting of kidney disease and AGEs in metabolic disorders, with an emphasis on the relevance to reducing adverse clinical outcomes such as CKD progression, cardiovascular events, and mortality. Overall, whether specific efforts to lower carbamylation and AGE burden will yield definitive clinical improvement in humans remains largely to be seen. However, the scientific rationale for such pursuits is demonstrated herein.

[Effect of dissipating phlegm and blood stasis simultaneously on AGEs/RAGE axis and oxidative stress in rats with diabetic myocardial microangiopathy]

OBJECTIVE

To investigate the effect of dissipating phlegm and blood stasis simultaneously for protecting cardiac microvascular endothelial cells (CMECs) against high glucose-induced injury and the role of AGEs/RAGE axis in the underlying mechanism.

METHODS

The primary CMECs were isolated from rat heart by enzymatic digestion and identified by immunofluorescence assay. The CMECs exposed to 33 mmol/L glucose for 48 h were divided into model group (MC), resolving phlegm (RP) group, dissipating blood stasis (DBS) group, dissipating phlegm and blood stasis (RPDBS) group and ALT-711 group. After treatment with 10% drug-containing serum and ALT-711 for 48 h, the content of AGEs in the cells were measured with ELISA. The expressions of RAGE mRNA and protein were measured with real-time quantitative PCR, immunofluorescence assay and Western blotting; The activity of NADPH oxidase and ROS level were measured by cytochrome c reduction and fluorescent probe DHE.

RESULTS

High glucose exposure significantly increased the content of AGEs, RAGE expressions at the protein and mRNA levels, NADPH oxidase activity and ROS level in the CMECs (P < 0.01). These changes were significantly mitigated by treatments with RP, DBS, RPDBS and ALT-711 (P < 0.01), among which RPDBS caused the most significant decrements in AGEs content, RAGE expression and NADPH oxidase activity (P < 0.01, P < 0.05). The reduction of ROS level in the RPDBS group was significantly greater than that in RP group (P < 0.01), but similar to that in DBS group (P > 0.05).

CONCLUSION

Dissipating phlegm and blood stasis simultaneously can be helpful for prevention and treatment of diabetic myocardial microangiopathy by suppressing the excessive activation of AGEs-RAGE signal axis and oxidative stress, thus protecting CMECs against high glucose-induced damage. Dissipating phlegm and blood stasis simultaneously is better than either of the therapy alone.

Effect of Advanced Glycation End-Products and Excessive Calorie Intake on Diet-Induced Chronic Low-Grade Inflammation Biomarkers in Murine Models

Chronic Low-Grade Inflammation (CLGI) is a non-overt inflammatory state characterized by a continuous activation of inflammation mediators associated with metabolic diseases. It has been linked to the overconsumption of Advanced Glycation End-Products (AGEs), and/or macronutrients which lead to an increase in local and systemic pro-inflammatory biomarkers in humans and animal models. This review provides a summary of research into biomarkers of diet-induced CLGI in murine models, with a focus on AGEs and obesogenic diets, and presents the physiological effects described in the literature. Diet-induced CLGI is associated with metabolic endotoxemia, and/or gut microbiota remodeling in rodents. The mechanisms identified so far are centered on pro-inflammatory axes such as the interaction between AGEs and their main receptor AGEs (RAGE) or increased levels of lipopolysaccharide. The use of murine models has helped to elucidate the local and systemic expression of CLGI mediators. These models have enabled significant advances in identification of diet-induced CLGI biomarkers and resultant physiological effects. Some limitations on the translational (murine → humans) use of biomarkers may arise, but murine models have greatly facilitated the testing of specific dietary components. However, there remains a lack of information at the whole-organism level of organization, as well as a lack of consensus on the best biomarker for use in CLGI studies and recommendations as to future research conclude this review.

Advanced glycation end products and their receptors in serum of patients with type 2 diabetes

Glycation is a non-enzymatic process involving the reaction of reducing sugars or reactive oxoaldehyde with proteins, lipids or nucleic acids, which results in the formation of advanced glycation end products (AGEs). The presented work discusses the glycation process in people with advanced stage of type 1 or type 2 diabetes. The concentration of different AGEs and their receptors for 58 serum samples was determined by ELISA and by spectrofluorimetric methods. In addition to fluorescent low molecular weight and protein-bound AGEs, we have also marked a new class of AGEs: melibiose-derived glycation product (MAGE). Our attention was also focused on the two groups of AGEs receptors: scavenger receptors (SR-A and SR-B) and RAGE. The correlation between the SR-AI scavenging receptors concentration and the fluorescence of AGEs as well as diabetes biological markers: GFR, creatinine contentration and HbA1c was demonstrated. A relationship between the concentration of AGEs and their receptors was also found in serum sample of patients treated with the metformin and aspirin. Furthermore, the concentration of SR-AI scavenger and the fluorescence of total AGEs was significantly lower in treated patients than in non treated patients. AGEs have also been found to contribute to the development of cardiovascular disease, atherosclerosis and diabetic complications, what could be deduced from the correlation of AGEs level and HDL cholesterol or uric acid level. Thus, it was confirmed that AGEs are involved in the pathomechanism of diabetes and other degenerative diseases. Nowadays, it is believed that AGEs due to the long time remaining in the body may be an important diagnostic marker. Their determination may allow monitoring the progression of the disease and the effectiveness of the therapy.

Carbonyl stress in diabetics with acute coronary syndrome

The prevalence and incidence of diabetes mellitus (DM) are increasing worldwide bringing with it a significantly higher rate of complications. Various mechanisms such as carbonyl stress, polyol pathway, oxidative stress, hexosamine pathways, diacylglycerol/protein kinase-C activation, etc., are responsible for the pathogenesis of DM and its complications. Persistent hyperglycaemia and inhibition of metabolising and detoxifying enzymes lead to the excessive synthesis of carbonyl compounds such as methylglyoxal, glyoxal, and 3-deoxyglucosone, resulting in carbonyl stress. The substrates, metabolizing and detoxifying enzymes of carbonyl compounds are discussed. The mechanistic roles of carbonyl compounds and advanced glycation end products (AGEs) in atherosclerosis, insulin resistance, thrombogenicity, and endothelial dysfunction in animal and cell culture model of DM and patients with DM are summarised. Because of the essential role of carbonyl stress, therapeutics are aimed at scavenging, metabolizing, detoxifying, and inhibiting carbonyl compounds or AGEs so that their harmful effects are minimized. Clinically used drugs, plants extracts and miscellaneous chemical with antiglycation properties are used in an animal model of DM to alleviates the impact of carbonyl compounds. Extensive clinical trials with derivatisation of available antiglycation agents to increase the bioavailability and decrease side effects are warranted further.

Dihydromyricetin attenuates D-galactose-induced brain aging of mice via inhibiting oxidative stress and neuroinflammation

Aging-related especially brain aging-related diseases are heavy health care burdens worldwide. Natural products with antioxidant and anti-inflammatory properties have been studied to prevent brain aging pathogenesis. In the present study we investigated the potential mechanism of dihydromyricetin (DMY), isolated from Ampelopsis grossedentata, against D-galactose (D-Gal)-triggered brain aging of mice. Mice were randomly assigned into five groups (n = 20): control group, D-gal (150 mg/kg) group, D-gal (150 mg/kg) + Puerarin group, D-gal (150 mg/kg) + DMY (168 mg/kg) and D-gal (150 mg/kg) + DMY (42 mg/kg). Morris water maze (MWM) was used to assess spatial cognition and oxidative stress and inflammation index such as advanced glycation end products (AGEs), malondialdehyde (MDA), IL-2 and IL-6 were detected by ELISA. Cellular senescence marker was detected by Western blotting analysis. We found that DMY (42 mg/kg) showed strong neuroprotective effects, evidenced by improved spatial cognition and might be attributed to the alleviated damage of hippocampal neurons. In addition, DMY also suppressed the D-Gal-induced senescence of hippocampal neurons by inhibiting the expressions of p53, p21, and p16. Furthermore, DMY restored the activity of catalase and exhibited a potent inhibitory effect on lipid peroxidation, AGEs and MDA of D-Gal-exposed mice. Moreover, DMY decreased the abundance of IL-6 but increased the abundance of IL-2 of D-Gal-exposed mice. These findings indicated that DMY might protect against brain aging caused by chronic D-Gal exposure by modulating oxidative stress and inflammation-related senescence of hippocampal neurons.

The cardiovascular complications of diabetes: a striking link through protein glycation

Diabetes mellitus is a predominant cause of mortality and morbidity worldwide. One of its serious health problems is cardiovascular complications. Advanced glycation end products (AGEs) are a group of heterogeneous toxic oxidant compounds that are formed after a non-enzymatic reaction between monosaccharides and free amino groups of proteins, compound lipids, and nucleic acids. AGE interacts with various types of cells through a receptor for AGE (RAGE). The interaction between AGE and RAGE is responsible for a cascade of inflammation, oxidative stress, and disruption of calcium homeostasis in cardiac cells of diabetic patients. There is striking evidence that the AGE/RAGE axis with its consequences on inflammation and oxidative stress plays a major role in the development of cardiovascular complications. Therefore, considering AGE as a therapeutic target with foreseeable results would be a wise direction for future research. Interestingly, several studies on nutraceutical, pharmaceutical, and natural products have begun to reveal promising therapeutic results, and this could lead to better health outcomes for many diabetic patients worldwide. This article discusses the current literature addressing the connection between protein glycation and diabetes cardiovascular complications and suggests future avenues of research.