Advanced glycation end products (AGEs) are stable molecules generated through the non-enzymatic glycation of proteins, lipids, or nucleic acids. This process is initiated by the interaction of reducing sugars with these biomolecules, resulting in the formation of early glycation intermediates such as Schiff bases and Amadori products (16).

According to studies, this reaction process can be roughly divided into early, intermediate, and advanced stages, with different products and characteristics at each stage (17). The carbonyl group on the open-chain form of glucose, fructose, or ribose reacts with the free amino group of biomacromolecules in the early stage with a reversible condensation reaction to form intermediate products aldimines, a type of unstable Schiff base that is susceptible to undergo rearrangement with the consequence of formation of more stable Amadori products (18, 19). In the intermediate stage, Amadori products degrade into dicarbonyl compounds through dehydration, oxidation, fission, and other reactions in an acid-base environment, containing various reactive fission products ready for further reactions (16). Finally, in the advanced stage, an extensive range of reactions, including dehydration, enolization, oxidation, fragmentation, rearrangement, isomerization, and further condensation, act on these dicarbonyl compounds, facilitating the production of irreversible AGEs, including hydroimidazolone, N^ε-carboxymethyl-lysine (CML), pentosidine, and glucosepane (17, 20–22). The entire process is usually applied in food processing to control and limit critical steps (19). The overall NEG procedure is illustrated in Figure 1.

The generation of AGEs occurs extensively in our life activities and metabolic processes, determining the functions of biological macromolecules, such as proteins, with the rate and extent of this reaction being affected by various factors within different physiological and pathological conditions.

AGEs serve as biomarkers in CVDs and diabetes and various in vivo measurement methods for AGEs have been employed in clinical studies to investigate their associations with these diseases.

Due to the inherent immunogenicity of AGEs, immunochemical methods including particularly enzyme-linked immunosorbent assay (ELISA) have been widely used in clinical studies to measure AGE levels in serum or plasma (34–36). Using this approach, studies have demonstrated significantly higher serum AGE concentrations in diabetic patients compared to healthy individuals (37).

Certain AGEs exhibit spontaneous fluorescence upon excitation, enabling their quantification through fluorescence intensity measurements. This property allows the bioanalytical method for detection of AGEs in serum and urine using fluorescence spectrophotometry (FS) (38, 39), as well as noninvasive assessment of skin AGEs via skin autofluorescence spectroscopy (SAF) (40, 41). Clinical studies utilizing these methods have revealed elevated AGE levels in various disease states. For instance, Galler et al. reported significantly higher serum levels of fluorescent AGEs in type 1 diabetes patients compared to healthy controls (38), while Suehiro et al. observed increased urinary AGE concentrations in metabolic syndrome patients at high cardiovascular risk relative to healthy individuals (39). For the noninvasive way, some clinical studies have demonstrated that T2D patients had higher value of SAF compared to controls (42), and the SAF results positively correlated with coronary artery calcification and microvascular complications (43, 44). SAF was also found independently associated with all-cause mortality and fatal or nonfatal major adverse cardiovascular events in patients with peripheral artery disease (45). These findings collectively highlight the widespread application of fluorescence-based bioanalytical technologies in clinical research investigating the biomarker potential of AGEs in cardiovascular diseases and metabolic disorders.

Chromatography-mass spectrometry techniques, including high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), and gas chromatography-mass spectrometry (GC-MS), represent another analytical approach for quantifying AGEs in serum and tissue samples. However, the clinical application of these methods remains limited due to their high operational costs and time-intensive procedures (46).

Modifications of proteins in cardiovascular tissues, including myocardial cells and vascular endothelial cells, and in plasma, will change their structures and functions, resulting in pathological effects in cardiovascular tissues.

In addition to the formation of AGEs in proteins, glycated lipids under hyperglycaemia or dietary levels also harm cardiovascular tissues in other ways.

Apart from the formation of AGEs in proteins and lipids, the glycated DNA contributes to cardiovascular tissue damage and other pathologies through mutagenesis and genomic instability.

The major nonenzymatic glycation product of DNA, N²-(1-carboxyethyl)-2′-deoxyguanosine (CEdG) (73, 74), has been shown to induce single-strand breaks and increase mutation frequencies in oncogenes and tumor suppressor genes (74), promote mutagenesis by altering base-pairing preferences due to its distinct syn/anti conformations during replication (75), and cause DNA damage when the nucleotide excision repair efficiency is compromised (76). These mechanisms collectively contribute to genetic instability and elevated cancer risk associated with metabolic diseases.

Acetoacetate, a ketone body increased during ketosis in diabetic patients has been found can activate effect on glucose-mediated DNA glycation during hyperglycemia because acetoacetate can induce ROS and ROS elicits DNA glycation (77). Clinical studies have found that CEdG was significantly elevated in diabetes as well, which implies the effects of DNA-AGE on diabetes and its potential on serving as biomarker of diabetes (78). Due to DNA damage resulting from many mechanisms like strand breaks induced by CEdG in the metabolic syndrome, the risk of various cancers and cardiovascular diseases will be elevated (79). However, it is worth mentioning that inhibition of glyoxylase 1 (GLO1) in cancers can increase levels of DNA-AGE and RAGE that is cytotoxic to glioma cells (80), implying the dialectical roles of CEdG in cancers. DNA damage also accompanies with aging and aggravates the incidence of neurodegenerative disease like Alzheimer disease and Parkinson disease (81).

Other structures of cardiovascular tissues impacted by AGEs are summarized in Table 1.

OS is linked to the levels of ROS, which include superoxide anion radicals (O²⁻), hydrogen peroxide (H₂O₂), and hydroxyl radicals (HO⁻). This is sometimes accompanied by reactive nitrogen species (RNS), such as nitric oxide (NO⁻), nitrogen dioxide (NO²), and peroxynitrite (ONOO⁻). Several mechanisms through which AGEs lead to OS and inflammation have been identified. First, AGEs create irreversible crosslinks with proteins and lipids, altering their structure and function, promoting ROS production and OS, as discussed in Sections 3.1, 3.2. Second, AGEs cause mitochondrial dysfunction by disrupting the respiratory chain and increasing mitochondrial stress, leading to excessive ROS production and OS (87). Third, AGEs cause OS and ROS production by interacting with RAGE. AGE-RAGE interaction activates nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX), resulting in ROS production (88, 89). Excessive ROS generation leads to abnormal oxidation and dysfunction of biomacromolecules, triggering the expression of inflammatory mediators, such as tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), cyclooxygenase 2 (COX-2), and prostaglandin E2 (PGE2) (88). Fourth, signalling pathways activated by the AGE-RAGE axis induce OS and inflammatory responses. The nuclear factor kappa B (NF-κB) signalling pathway is the main pro-inflammatory pathway in ROS and OS production, leading to vascular injury. NF-κB is a transcription factor sensitive to free radicals that regulates the transcription of endothelin-1, VCAM-1, tissue factor, and thrombomodulin, which relate to vascular functions (90). ROS production in endothelial cells stimulated by AGEs is mediated by NF-κB signaling, where NF-κB induces TNF-α expression, mediating ROS generation (91). Additionally, Rho/Rho-associated protein kinase (Rho/ROCK) expression mediated by AGEs is involved in NF-κB signalling pathway and ROS production (92, 93). The Janus kinase-signal transducers and activators of transcription (JAK-STAT) signalling pathway is activated by AGE-RAGE, leading to JAK phosphorylation and STATs activation. Phosphorylated STATs form dimers and move into the nucleus to regulate transcription of inflammatory cytokines, such as interleukin-6 (IL-6), TNF-α, and MCP-1, and inducible enzymes like iNOS and COX2 (94). Moreover, RNS production is mediated by the AGE-RAGE axis, contributing to OS (95).

After OS and inflammatory reactions induced by AGEs, further increased production of AGEs can be triggered by OS and inflammatory reactions themselves, as mentioned in Sections 2.2.2, 2.2.3. This is how the vicious circle is generated, which gradually aggravates the implications of OS and inflammatory reactions. Furthermore, it was proven that the enhancement of NOX activity and activation of NF-κB induced by AGE-RAGE interactions will facilitate the expression and production of iNOS and ONOO⁻, namely the overproduction of RNS that also results in OS (95). RNS is involved in the production of AGEs (96), which also serves as a part of the vicious circle.

The occurrence of OS and accumulation of inflammatory cytokines such as C-reactive protein (CRP), IL-1β, IL-6, TNF-α and so on will subsequently trigger the oxidative damage of biomacromolecules in vivo and aggregation of inflammatory cells, which ultimately leads to the impairment of cardiovascular structures and development of CVDs.

AGE can directly initiate injury in cardiovascular cells involving myocardial cells, vascular endothelial cells, smooth muscle cells, and so on to affect their normal physiological functions. Endogenous AGEs produced inside myocardial cells and cardiac fibroblasts are proven to embody cytotoxic and cause CVDs. It was indicated that AGEs in cardiomyocytes could decrease pulse rate and cell activity and induce cell death, which concerns the suppression of autophagy. It is an essential mechanism for maintaining cell homeostasis via the degradation of aging and damaged proteins and organelles (97). AGEs in cardiac fibroblasts exert cytotoxicity and inhibit their roles in regulating myocardial ECM homeostasis and restoring damaged cardiac functions. Furthermore, with the expression of RAGE in cardiomyocytes and cardiac fibroblasts, the AGE-RAGE axis may also induce cytotoxic reactions and dysfunction in these cells (98). Extracellular AGEs also facilitate CVDs through the AGE-RAGE axis, which activates the production of ROS and, subsequently, the NF-κB signalling pathway in vascular wall cells, contributing to atherosclerosis (99).

Recent studies have suggested that the interaction between AGEs and RAGE can destroy the balance of osteogenesis and osteoclastic in VSMCs to promote vascular calcification and pathological bone remodelling (100, 101), contributing to atherosclerosis development. Another mechanism that elicits calcium deposition in VSMCs is Nox-derived OS, which is involved in AGE-induced apoptosis of VSMCs (102). Moreover, it was proven that the interaction between AGEs and RAGE could induce the expression of the pro-sclerotic cytokine TGF-β, which mediates the trans-differentiation of smooth muscle cells to myofibroblasts (103), which may promote vascular stiffness through the destruction of VSMCs.

Studies have demonstrated that AGEs boost vascular endothelial growth factor (VEGF) production and activate its autocrine function in endothelial cells, resulting in angiogenesis. Overexpression of RAGE can trigger reactions in endothelial cells, highlighting the AGE-RAGE axis (104). Profilin-1, an intracellular protein associated with actin, regulates endothelial cell contraction and vascular permeability. AGEs elevate profilin-1 levels in endothelial cells, causing cytoskeletal changes and cell damage, evident from increased endothelial cell permeability, apoptosis initiation, and enhanced cell migration, adhesion, and focal contact formation (105). Additionally, myosin light chain (MLC) phosphorylation by MLC kinase (MLCK) promotes cytoskeletal contractile activity and disrupts tight junctions, increasing endothelial permeability. AGEs in endothelial cells can decrease miR-1-3p expression, a microRNA with therapeutic potential in treating endothelial dysfunction. This decrease amplifies MLCK signalling, leading to cytoskeletal contraction, increased vascular permeability, endothelial cell aging, and barrier dysfunction (106). Endothelial progenitor cells (EPCs), particularly late EPCs, vital for endothelial maintenance, repair, and postnatal angiogenesis, are negatively impacted by AGEs in a concentration-dependent manner, disrupting proliferation, migration, adhesion, and inducing apoptosis (107).

In addition to direct impairment of cardiovascular cells by AGEs, modification of ECM components by AGEs leads to alterations in structure and function that contribute to CVD pathological effects. As mentioned in Section 3.1, AGEs modify essential ECM proteins, such as collagen and elastin, affecting their physiological functions by changing crosslink structures. Ligation of AGEs and RAGE may alter the production of these ECM proteins, leading to changes in elastic fibres and increased carotid diameter (108). This is associated with arterial stiffness and atherosclerosis risk. Furthermore, studies show that exercise training can inhibit advanced glycation by reducing CML and RAGE expression, which attenuates aortic stiffening and prevents endothelial dysfunction marked by decreased collagen levels, increased elastin levels, and reduced pulse wave velocity (PWV), with RAGE inhibitor FPS-ZM1 achieving similar effects (109). This indicates the dynamic relationship between collagen and elastin relates to vascular physiological conditions. AGEs may attenuate elastin levels and increase collagen levels to aggravate aortic stiffness, contributing to CVD pathological responses. Beyond glycated collagen that can attenuate vascular wall flexibility and arterial and myocardial compliance, as noted in Section 3.1.1, glycated structural extracellular proteins contribute to myocardial stiffness, causing impaired relaxation and diastolic dysfunction (110). Glycated type IV collagen and laminin can reduce endothelial cell adhesion and spreading by disrupting cell attachment sites (111), destroying endothelial cell integrity and functions.

Glycation of other ECM components, such as fibrinogen and LDL, as mentioned in Section 3.1.2, generally contributes to thrombogenesis, reduction of fibrinolysis, and risk of atherosclerosis. Other studies have shown that irreversible AGE-induced modifications of ECM components, such as type IV collagen, laminin, and vitronectin, can facilitate the overproduction and accumulation of ECM and vasoconstriction (112), which contributes to the accumulation of fibrous tissue, resulting in myocardial fibrosis and hypertension. Furthermore, the AGEs–RAGE axis induces autophagy, which can activate cardiac fibroblasts, which are responsible for the secretion of collagenous extracellular matrix proteins, such as collagen I and collagen III. Activated cardiac fibroblasts transform into myofibroblasts and accumulate in the myocardium. Increased ECM component deposition and myofibroblast accumulation contribute to myocardial fibrosis in heart failure (113). AGEs also increase the expression of KCa3.1 channels in a RAGE-dependent manner by activation of ERK1/2, p38-MAPK, and PI3K/Akt signalling, thereby promoting the proliferation of cardiac fibroblasts and ECM (114), which is another mechanism of deposition of ECM components that correlates to myocardial fibrosis. The small GTPase Rap1a modifies and activates downstream events of the AGE/RAGE signalling cascade to increase cardiac fibroblast collagen gel contraction and ECM remodelling (115). TGF-β signalling interacts with RAGE signalling or independently causes ECM remodelling (116). Consequently, myocardial fibrosis is exacerbated.

After discussing the direct effects of AGEs on OS, inflammation, cell dysfunction, and ECM remodelling that elicit pathological responses in CVDs, we will illustrate the mechanisms by which glycation disrupts normal transduction of crucial signalling pathways in CVDs to microscopically explore the impairment of AGEs on cell metabolism and survival in the development of CVDs. A related illustration is shown in Figure 2.

Activation of the RAGE/NF-κB signalling pathway by AGEs is a prevalent mechanism that contributes to the progression of cardiovascular diseases. Recent research has shown that AGEs trigger the RAGE-NF-κB signalling cascade, leading to increased NF-κB signalling. Concurrently, the NF-κB subunit p65 is drawn to the RAGE promoter, which boosts RAGE transcription and establishes a positive feedback loop between NF-κB signalling and RAGE expression, further amplifying the NF-κB signalling pathway. Consequently, various downstream effectors of this pathway are activated to perform their respective roles. Caveolin-1, a key membrane-bound scaffolding protein found in caveolae, acts as a downstream effector of the RAGE/NF-κB signalling pathway and is involved in LDL transcytosis in endothelial cells. Enhanced NF-κB signalling leads to the upregulation of Caveolin-1, facilitating LDL transcytosis and causing LDL to deposit beneath the endothelium, which ultimately contributes to the development of atherosclerotic plaques (117).

Protein kinase C (PKC) is a collection of enzymes within the AGC family (cAMP-dependent protein kinase/protein kinase G/protein kinase C) that function as serine/threonine-related protein kinases and play a role in cell signalling (118). The RAGE/PKC-β pathway is another signaling mechanism implicated in vascular dysfunction, where AGEs trigger the increased production of monocyte chemotactic protein-1 (MCP-1) in monocytes and endothelial cells, as well as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in endothelial cells during inflammatory conditions and oxidative stress. This process leads to macrophage adhesion to endothelial cells, contributing to endothelial dysfunction (119, 120). Additionally, AGEs influence the RAGE/PKC-β signalling pathway by enhancing the expression and phosphorylation of PKC-β1/2 in cardiac microvascular endothelial cells (CMECs), promoting CMEC proliferation and reducing early apoptosis, potentially playing a role in the development of cardiomyopathy (121).

Research shows that the RAGE/phosphatidylinositol 3-kinase (PI3K)/AKT signalling pathway is activated by AGEs and regulates cellular functions. AGEs increase the expression of proteins related to cell proliferation and migration, as well as filamentous actin, in human aortic vascular smooth muscle cells (HASMCs). This leads to HASMC proliferation and migration, causing intimal hyperplasia and lumen stenosis, conditions linked to arteriosclerosis development (122). The mechanism behind VSMC proliferation involves autophagy triggered by AGEs through the ERK signaling pathway, a member of the mitogen-activated protein kinase (MAPK) family, and AKT signaling pathways. AGEs promote ERK phosphorylation while inhibiting AKT phosphorylation (123). Studies suggest that inhibiting AGE-induced apoptosis in endothelial cells can be achieved by activating the ERK1/2 and PI3K/AKT signalling pathways (124). This indicates that AGEs' impact on apoptosis and endothelial cell death may involve the ERK1/2 and PI3K/AKT pathways.

Rho is an essential small GTP-binding protein that functions as a molecular switch in signal transduction and plays a crucial role in remodelling the actin cytoskeleton across various cell types. Research has shown that the RAGE/Rho signalling pathway can be triggered by AGEs, leading to the expression of RhoA in endothelial cells. This process enhances microvascular hyperpermeability through actin polymerization and the reorganization of the actin cytoskeleton (125).

Research has demonstrated that the interaction between AGEs and the receptor for advanced glycation end-products (RAGE) can trigger Toll-like receptor 4 (TLR4) signalling. This activation promotes ERK phosphorylation, which in turn increases the expression of FOXC2 and subsequently delta-like ligand 4 (Dll4) in macrophages during M1 polarization. FOXC2, a transcription factor from the forkhead family, is essential for vascular development and integrity, whereas Dll4 can activate the Notch signalling pathway, which is vital for the phenotypic conversion of vascular smooth muscle cells (VSMCs) from a contractile to a synthetic state. Consequently, within the RAGE/TLR4/FOXC2 signalling pathway, the high expression of Dll4 induced by AGEs in macrophages through direct cell-to-cell interaction mediates the Notch signalling pathway, leading to the formation and progression of atherosclerotic plaques characterized by VSMCs transitioning from contractile to synthetic phenotypes (126). The RAGE/ILK/mTOR/p70S6K signalling pathway is another key player in the advancement of atherosclerosis, with ILK acting as a versatile intracellular serine/threonine kinase that contributes to the pathogenesis of the disease. Within this pathway, AGE activation triggers the expression of proteins in the ILK/mTOR/p70S6K signalling pathway, leading to VSMC-to-osteoblast trans-differentiation and cell proliferation, which in turn fosters the progression of atherosclerosis (127).

Certain signalling pathways are triggered by ROS, which is facilitated by AGEs. AGE-RAGE-mediated production of ROS activates the Ang II-TGF-β–Smad pathway. In this pathway, ROS-induced autocrine production of Ang II in mesangial cells leads to TGF-β expression and Smad phosphorylation, resulting in mesangial cell hypertrophy and fibronectin synthesis (128). ROS production through AGE-RAGE interactions stimulates p38 and JNK within the MAPK signalling pathway, initiating cascades that activate cascade-3 and FOXO1, promoting fibroblast apoptosis (129). AGEs may also induce vascular adventitial fibroblasts (AFs) migration and inflammatory mediator release by upregulating RAGE expression via MAPK signalling and NF-κB activation, contributing to early atherosclerosis development (130).

Heart failure is a progressive clinical syndrome resulting from diverse cardiovascular abnormalities, such as coronary artery disease, myocarditis, hypertension, and cardiomyopathy, ultimately leading to impaired atrial or ventricular ejection of blood (131). Plentiful evidence acknowledged that AGEs is related to pathophysiological mechanisms of heart failure (11). Both the accumulation of AGEs in the ECM and activation of AGE-RAGE signaling affects cardiac dysfunction by two central mechanisms (132–134).

Extracellular matrix (ECM) remodeling is a hallmark of heart failure, where pressure overload promotes excessive ECM synthesis, contributing to both diastolic and systolic dysfunction (135, 136). AGE formation manipulates ECM remodeling by altering their structures and functions, especially collagen. AGEs in collagen leads to crosslinks in ECM that contribute to myocardial stiffness and left ventricular ejection fraction (LVEF) (137, 138). In mouse models of heart failure, a reduction in collagen type III alongside the accumulation of advanced glycation end products (AGEs) has been observed. Treatment with crosslink breakers was shown to restore collagen function while simultaneously reducing AGE formation (110). As the most critical AGE precursor, Methylglyoxal (MG) overexpression in transgenic mice increased ECM remodeling in scarring myocardium (139). In the study, Methylglyoxal (MG) was observed with co-localization of collagen I in cardiac tissues after myocardial infarction, suggesting non-enzymatic glycation in cardiac tissue was linked to increased fibrosis and hypertrophy. From a clinical perspective, Willemsen et al. demonstrated that patients with heart failure exhibit elevated tissue levels of AGEs, which are associated with diastolic dysfunction and reduced aerobic exercise capacity (140). While increased AGEs were independently associated with reduced exercise capacity, another study found that either continuous or interval exercise training regimens prevented artery stiffness via mitigation of AGE level (141). Collectively, these studies emphasized the adverse effect of AGEs on heart failure and implied possible therapeutic options of exercises for heart failure patients. AGEs exert their effects mainly by binding to RAGEs and initiating several signaling transduction in the cardiac tissue (142, 143). For example, activation of RAGE enhanced NF-κB activation and promoted myofibroblast transition and oxidative stress in heart failure (144, 145). TGF-β1/Smad pathway was another downstream signaling cascade of the AGE-RAGE axis in myocardial fibrosis, an essential heart failure process. Pretreatment of anti-RAGE antibody substantially decreased TGF-β1 and p-smad2/3 expression of cardiac fibroblasts, suggesting the presence of RAGE/TGF-β signaling pathway in heart failure (146).

The four major valves in the heart includes three kinds of valvular problems: atresia (block of the valve), regurgitation (backflow of blood through the valve), and stenosis (narrowness of the valve) (147–149). Chronic glycation of proteins has been in many valvular heart diseases, such as stenotic aortic valves, mitral valve disease, and congenital valvular disease (bicuspid aortic valve). By contrast, the accumulation of AGEs is related to disease severity and progression (150–152).

Aortic valve stenosis (AVS), the most common aortic valve disorder, is driven by fibrocalcific remodeling of valve leaflets. Chronic inflammation contributes to calcification (153), and AGE–RAGE signaling promotes valve interstitial cell trans differentiation into osteoblast-like cells with immune cell infiltration (154). A diet rich in carbohydrates and fats enhances AGE–LDL formation, which in turn promotes aortic valve lesions in hamsters. In human aortic valve interstitial cells, AGE–LDL induces the expression of inflammatory mediators, including ICAM-1, IL-6, and ALP, and facilitates calcific nodule formation. Conversely, silencing the RAGE gene attenuates these effects by suppressing NF-κB signaling (155). The sex difference of AGE synthesis was reported in SD rat models, and male SD rats have higher AGEs than female rats, indicating that males are more likely to suffer from CVDs (156). In a study of patients with kidney failure, male patients are more prone to aortic valve calcification with higher AGE accumulation (157).

Heart valve replacement is the only treatment for symptomatic severe valve diseases (158). However, the increasing prevalence of valve degeneration is expected to emerge as a leading cause of cardiovascular morbidity and a significant healthcare burden in the coming decades (159). Several causes contribute to valve degeneration: calcification of the bioprosthetic valve, inflammatory reactions, tissue thickening, and collagen network (160). Immunohistochemistry on 45 clinical explants revealed that AGE and HSA accumulation are standard features in failed BHVs, exhibiting collagen crosslink regardless of calcification severity. Moreover, in vitro infiltration of bovine pericardium demonstrated that this effect of AGEs accumulates mainly in lysine and arginine. The process occurs as early as implantation starts, that affects the effective orifice area of the bioprosthetic valve, indicating AGEs as one cause of implantation failure (161).

Coronary Artery Disease (CAD) is a chronic condition characterized by the progressive narrowing or blockage of the coronary arteries, leading to a complex interplay of endothelial dysfunction, foam cell accumulation, inflammation, and thrombosis (162). Two RNA-binding proteins, nuclear factor 90 (NF90) and nuclear factor 110 (NF110), mediate AGE accumulation in vascular smooth muscle cells (VSMCs) via stimulating the degradation of AGE receptor 1 (AGER1) (163). Atherosclerosis is initiated when LDL becomes retained within the sub-endothelial layer of medium and large arteries. This upregulation of AGE-RAGE cascade in macrophages facilitates increased binding and internalization of modified low-density lipoproteins (LDL), such as oxidized LDL (ox-LDL), into the macrophages. Internalized cholesterol forms cholesterol esters in the macrophage stored as lipid droplets, contributing to foam cell formation in the early stage of atherosclerotic lesions (164). LDL cross endothelial cells (ECs) via transcellular transcytosis, which is mainly mediated by Caveolin-1 protein (165, 166). Interaction between AGE and RAGE on the ECs robustly upregulated Caveolin-1. AGE-RAGE signaling promoted phosphorylation of transcription factor NF-κB, which, in turn, translocated into the nucleus and increased expression of upstream RAGE and Caveolin-1. Therefore, AGE-RAGE-NF-κB forms a positive feedback loop in the LDL transcytosis (117).

As one of the most prevalent and studied AGEs, CML arising through the nonenzymatic glycation and oxidative modification of monosaccharides (such as glucose) and protein-bound lysine residues (167). Notably, in vivo experiments suggested that CML accelerates the formation of atherosclerosis via the migration of foam cells into regional lymph nodes. Injection of exogenous CML into diabetic apoE−/− mice promoted plaque formation and cholesterol crystal deposition in the plaques. Moreover, CML upregulates the expression of CD36, a signal molecule expressed by macrophage-derived foam cells, indicating the accumulation of foam cells in atherosclerosis formation. in vitro analysis demonstrated that CML inhibited foam cell migration via ROS generation and FAK signaling, which are responsible for macrophage migration (167). A comparative study assesses CML levels as a predictor factor for coronary artery disease in diabetic patients (168). The result showed that patients with more severe coronary artery diseases have higher CML accumulation. Additionally, CML is related to several inflammatory factors up-regulation, such as TNF-α and IL-6, which is highly correlated with early atherosclerotic lesion formation and increased long-term cardiovascular mortality (169).

Systemic arterial hypertension, commonly referred to as hypertension, is a significant CVD characterized by persistently elevated pressure within the arteries (170). Arterial stiffness is a leading factor in the development of hypertension. Elastic arteries enhance the effects of cardiac contraction during the diastolic stage by storing potential energy when they expand elastically during the systolic stage. However, they become less able to absorb the force of blood ejected from the heart as artery stiffen, leading to higher systolic blood pressure and an increased pulse pressure (171).

AGEs in cardiomyocytes is related to arterial stiffness, demonstrating that higher pulse wave velocity (PWV) and pulse pressure were positively related to elevated plasma AGEs (172). Aging is markedly associated with arterial stiffness due to structural and functional changes in the vascular system (173). One comparative study showed that older participants exhibited a notable increase in PWV with higher plasma AGE levels in an age-dependent manner (174). The relationship between arterial stiffness and AGEs is restricted to patients with vascular diseases and induces early vascular changes before the disease. In men and younger individuals, vascular stiffness was significantly associated with AGE accumulation, implying it as a non-invasive marker for arterial stiffness (175).

Considering the potential involvement of AGEs in arterial stiffness, it would be anticipated that elevated AGE levels correlate with hypertension. Recently, a study investigated the role of elevated AGE levels and CVD in an elderly cohort; however, In the survey, AGEs demonstrated no correlation with hypertension in the cohort, and diastolic blood pressure was even negatively associated with skin autofluorescence (AGE markers) (15). This debate may be explained by age difference in diastolic blood pressure: earlier studies conducted in all age ranges demonstrated that AGE levels were positively related to blood pressure in men and children (176).

Hypertension substantially elevates the risk of mortality associated with cardiovascular events (177). A large-scale meta-analysis examined the association between hypertension and mortality across 67 distinct causes of death. The findings revealed that hypertension was associated with an increased risk of all-cause mortality and elevated risks for 17 specific causes, predominantly circulatory diseases. HGI is a measure that quantifies the difference between observed and predicted HbA1c levels based on blood glucose concentration, reflecting individual variability in of hemoglobin (178). Notably, cardiovascular events in female hypertensive patients increased with higher HGI levels, demonstrating a J-shaped relationship (14).

In the past decades, diabetic-induced heart failure, cardiomyopathy, hypertension, and coronary diseases have received markedly research attention to relative mechanisms (179). People with diabetes have two sources of AGE initiation: exogenous and endogenous sources (180). Diabetic cardiomyopathy (DCM) is a distinct pathological condition in which heart failure develops independently of coronary artery disease, hypertension, or valvular abnormalities. It typically manifests first as diastolic dysfunction and progresses over time to heart failure with reduced ejection fraction. In diabetic patients, insulin resistance, compensatory hyperinsulinemia, and persistent hyperglycemia collectively contribute to the heightened susceptibility to DCM (181).

AGEs are generated in DCM development through promoting ferroptosis: AGEs were found to induce ferroptosis in cardiomyocytes via alteration in the expression of key ferroptosis markers, such as Ptgs2, ferritin, and SLC7A11, which in turn, contributing to the development of DCM. Also, AGE increases oxidative stress in the cell via activation of AMPK signaling, aggravating cell viability in DCM mice. These changes further led to cardiomyocyte dysfunction and structural remodeling. Furthermore, the study found that activating the AMPK/NRF2 signaling by sulforaphane attenuates ferroptosis in the AGE-treated group, allowing cardiomyocyte survival and providing potential therapeutic options to activate NRF2 in DCM treatment (182). AGEs bound to human serum albumin in cardiac cells downregulated Nrf-2 expression and its target antioxidant genes Keap1, HMOX1, and NQO1 expression, reducing cellular defense against oxidative damage (183).

Microtubule (MT) dysfunction was identified as a driver for contractile ventricular diseases (184). Increased stability of cardiac microtubules plays a significant role in the cardiac dysfunction observed in STZ-induced type 1 diabetic rats (185). Excessive AGEs cultured cardiomyocytes reduced SIRT2 expression, a gene responsible for cytoskeleton stability and the deacetylation of microtubules in the progression of diabetic cardiomyopathy (DCM). Injection of AGE neonatal rat ventricular myocytes enhances leakage of Ca2 + from the sarcoplasmic reticulum (SR), leading to partial depletion of SR Ca²⁺ stores and a subsequent reduction in systolic Ca²⁺ transients, finally causing contractile dysfunction in diabetic cardiomyopathy (186).

Diabetes is universally acknowledged as an inflammatory disorder, as the impairment in insulin secretion and sensitivity is attributed to factors such as proinflammatory proteins and immune infiltration in DCM patients (187). Previous experimental evidence found that myeloid differentiation 2 (MD2), a co-receptor for toll-like receptor 4 (TLR4), could induce inflammatory response in DCM development. AGEs and MD2-TLR4 form a complex that upregulates MAPK/ NF-κB and other proinflammatory factors (188). Macrophage polarization is crucial in immune responses, inflammation, and tissue remodeling. This plasticity allows macrophages to switch between two central polarization states, M1 (proinflammatory) and M2 (anti-inflammatory or tissue-repairing) (189). Excessive AGE accumulation induces the expression of microRNA miR-471-3p in bone marrow–derived macrophages (BMDMs) from diabetic mice as well as in RAW264.7 macrophage cells. Mechanistically, miR-471-3p directly binds to silent information regulator 1 (SIRT1), which was reported to have an anti-inflammatory role in switching macrophage polarization from M1 to M2 in DCM development (190).

AGEs may exert detrimental effects on congenital heart malformations starting from embryo development. For example, the accumulation of CML and MG upregulates smad proteins phosphorylation, thus leading to more borderer myocardium in the cushions of the outflow tract and more likely to develop congenital heart diseases (191). The bicuspid aortic valve (BAV) is the most prevalent congenital heart abnormality and is often linked to abnormalities in the proximal aorta (192). BAV encompasses a range of morphological abnormalities where the aortic valve consists of two functional cusps and has fewer than three distinct zones of parallel cusp apposition (193). One study investigated the lifetime health outcomes of individuals with BAV over a median follow-up of 19.1 years. It showed that a significant portion of deaths in BAV patients were linked to cardiovascular complications, particularly aneurysm formation, aortic dilatation and aortic dissection or rupture (192). BAV patients possess higher levels of AGEs that play a crucial role in cell apoptosis, thus increasing the risk of structural changes in the development of aortic aneurysms and the likelihood of acute aortic dissection. Therefore, the sRAGE may serve as a tool to predict the risk of BAV and BAV-associated aortopathies (194). Mechanistically, higher sRAGE levels correlate with increased activation of the NF-κB pathway, a key regulator of inflammation and cellular stress responses. This activation may contribute to the structural remodeling of aortic aneurysms in BAV patients (195). Increased levels of AGE also enhanced vimentin expression, which is a 48 kDa fragment cleaved by caspase-3 in cell apoptosis. Additionally, vimentin may function as a mechanotransducive regulator of Notch signaling, contributing to arterial wall remodeling (150).

Inhibitors of RAGE can reduce cardiac fibrosis and enhance diastolic function by downregulating AGE-RAGE signaling. Atorvastatin (Ator), originally identified for its lipid-lowering properties, has also been reported to activate peroxisome proliferator-activated receptor gamma (PPAR-γ) signaling. PPAR-γ could exert inhibiting effects on the AGE-RAGE axis, leading to the downregulation of ERK1/2 phosphorylation in rat fibroblast. Previous studies have proved the effects ERK1/2 in cell proliferation in many CVD models, such as left ventricle hypertrophy and cardiac fibrosis (196). Similarly, FPS-ZM1, another RAGE-specific inhibitor, upregulates AMPK phosphorylation and downregulates mTOR/NF-κB in cardiac tissue. Activation of AMPK mediates protective effects against systolic overload-induced cardiac dysfunction, whereas activation of mTOR/ NF-κB has detrimental effects that act as pro-inflammation and pro-apoptotic drivers. Consequently, the blocking effects of FPS-ZM1 suppressed inflammation and cardiac remodeling in heart failure (197). Although RAGE inhibition holds promising therapeutic potentials in AGE-mediated cardiovascular injury, several safety concerns in the application of RAGE inhibitors in other diseases warrant more investigation in future clinical trials. In early Phase I and II trials of Alzheimer disease, high doses of azeliragon (small-molecule RAGE antagonist) could increase falls, confusion, and cognitive decline, leading to early discontinuation of the high-dose arm (198).

AGE-crosslink breakers restore cardiovascular function by disturbing the formation of glycogen-dependent crosslinks. ALT-711 is a phenyl-4,5-dimethyl thiazolium chloride derivative used in many types of CVDs, including systolic hypertension, heart failure, and other aging-related heart dysfunction (199, 200). Mechanistically, ALT-711 effectively reverses significant artery stiffness in diabetic animals, restoring vascular properties toward normal levels. Diabetic mice treated with ALT-117 for three weeks demonstrated increased systemic arterial compliance (0.87 ± 0.08 ml/mmHg than 0.56 ± 0.05 ml/mmHg in untreated diabetic mice). Similarly, carotid artery compliance rose from 0.28 ± 0.03 mm²/mmHg in untreated diabetics to 0.45 ± 0.05 mm²/mmHg post-treatment (201). Another study investigated the effect of ALT-711 on left ventricle stiffness. After one month of daily ALT-711 administration, a significant reduction of approximately 40% in LV stiffness was observed, with measurements decreasing to 33.1 ± 4.6 mm Hg·m²/ml. This decrease in stiffness was accompanied by improvements in cardiac function, including increased LV end-diastolic volume and stroke volume, without significant changes in systolic blood pressure or heart rate (202).

Soluble forms of RAGE (sRAGE) could be generated from two primary sources: first, cleaved RAGE (cRAGE) is generated through the proteolytic shedding of membrane-bound RAGE by matrix metalloproteinases; second, endogenous secretory RAGE (esRAGE) is synthesized from RAGE gene. sRAGE has protective effects for cardiomyocytes via suppression of cell apoptosis and mitigation of angiogenesis, making it one of the hot points of therapy strategy in CVDs. sRAGE significantly restored left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) in I/R mice. Immunohistochemical staining for CD31 revealed increased capillary density in sRAGE-treated hearts, suggesting that sRAGE promotes angiogenesis following I/R injury. Meanwhile, the expression of pro-angiogenic genes, such as Akt, MAPK signals, VEGFR2, and STAT3, were significantly increased in sRAGE-treated cardiac microvascular endothelial cells (CMECs). Collectively, these angiogenic effects lead to improved cardiac function and reduced tissue damage post-injury (203). sRAGE treatment could also downregulate the expression of apoptosis markers and autophagy-related proteins. Therefore, I/R injured myocardial tissues observed reduced TUNEL-positive cells, lower caspase-3 activity, and decreased autophagosome formation (204). Cardiac dysfunction can lead to the opening of the mitochondrial permeability transition pore (mPTP), subsequent generation of reactive oxygen species, and mitochondrial calcium overload. Exogenous administration of sRAGE inhibits mPTP opening and mitochondria-mediated apoptosis by suppression of mitochondria cytochrome c, caspase 3, and caspase nine release (205).

In recent years, nanoparticles (NP) have been developed as an innovative drug delivery system, utilizing 1–100 nm biomaterials to transport therapeutic agents into diseased tissues (206). NPs targeting the AGE accumulation are an emerging class of agents for therapeutic interventions and diagnostic imaging in other diseases. For example, one study constructs a novel biocompatible nanoparticle encapsulated with argpyrimidine, an AGE that targets the nanoparticle to cell surfaces that express RAGE. The results showed that compared to free soluble anti-hyperglycemia drugs, anti-hyperglycemia drugs encapsulated inside argpyrimidine are more effective in controlling hyperglycemia in diabetic rats. Moreover, rats treated with nanoparticles demonstrated better structural integrity in heart integrity and less cardiac fibrosis formation (207). As discussed above, AGE/RAGE is associated with inflammation status in ischemia injury. PEI/siRAGE is a small interfering RNA nanoparticle that selected RAGE as the target gene to assess its in vivo efficacy. Compared with a control group treated with saline, PEI/siRAGE reduces more than 10% of the infarcted size in cardiac tissue, exhibiting a beneficial effect against myocardial infarction (208). Curcumin and aged garlic extract are modified herbal medicines that demonstrated anti-oxidative and anti-glycation impacts in treating CVDs (209, 210). However, limited solubility and low bioavailability impede their efficacy for more cardiovascular applications. A study investigated the impact of nanomedicine based on these two herbal medicines targets both AGEs and ROS in streptozotocin-induced diabetic rats: Both nano-curcumin and AGE demonstrated downregulation of RAGE gene level, and histopathological results also exhibited higher structural integrity in DCM tissue (211). The study by Lu et al. reveals a novel advantage of engineered macrophage membrane-coated siRNA nanoparticle (MMM/RNA NP) platform with overexpression of RAGE in the surface of MMM/RNA NP, through which the nanoparticle effectively achieved higher cellular internalization to the site of myocardial ischemia–reperfusion injury, leading to improved left ventricular ejection fraction (LVEF) and fractional shortening (LVFS) in ischemic mice (212).