Accumulation Of Advanced Glycation End Products Research Articles

Association between advanced glycation end-products and fall risk in older adults: The Yakumo Study.

Advanced glycation end-products (AGEs) are irreversibly and heterogeneously formed compounds during the non-enzymatic modification of macromolecules, such as proteins. Aging and lifestyle habits, such as high-fat and high-protein diets, and smoking, promote AGEs accumulation. This study aimed to investigate the relationship between fall risk and AGEs in community-dwelling older adults. This cross-sectional study included patients from the 2022 Yakumo Study who were evaluated for fall risk index 5-items version, locomotive syndrome stage and AGEs. AGEs were evaluated using Skin autofluorescence (SAF) measured by the AGE reader (DiagnOptics Technologies BV, Groningen, the Netherlands). We divided the participants into two groups according to the presence or absence of fall risk (fall risk index 5-items version ≥6 or not), and investigated the factors associated with fall risk. The fall risk group had a higher age and SAF, and a higher proportion of locomotive syndrome stage >2 than the without fall risk group in patients aged ≥65 years (P < 0.01). The multivariate logistic regression analysis after adjustment of age, sex and body mass index showed that locomotive syndrome stage ≥2 and SAF were independent associators of fall risk in older adults (odds ratio 3.26, P < 0.01, odds ratio 2.96, P < 0.05, respectively). The optimal cutoff value of the SAF for fall risk was 2.4 (area under the curve 0.631; 95% CI 0.53-0.733; sensitivity 0.415; specificity 0.814; P < 0.05). The accumulation of AGEs in skin tissues can be used to screen for fall risk comprehensively. Geriatr Gerontol Int 2024; ••: ••-••.

Bone canonical Wnt signaling is downregulated in type 2 diabetes and associates with higher advanced glycation end-products (AGEs) content and reduced bone strength.

Type 2 diabetes (T2D) is associated with higher fracture risk, despite normal or high bone mineral density. We reported that bone formation genes (SOST and RUNX2) and advanced glycation end-products (AGEs) were impaired in T2D. We investigated Wnt signaling regulation and its association with AGEs accumulation and bone strength in T2D from bone tissue of 15 T2D and 21 non-diabetic postmenopausal women undergoing hip arthroplasty. Bone histomorphometry revealed a trend of low mineralized volume in T2D (T2D 0.249% [0.156-0.366]) vs non-diabetic subjects 0.352% [0.269-0.454]; p=0.053, as well as reduced bone strength (T2D 21.60 MPa [13.46-30.10] vs non-diabetic subjects 76.24 MPa [26.81-132.9]; p=0.002). We also showed that gene expression of Wnt agonists LEF-1 (p=0.0136) and WNT10B (p=0.0302) were lower in T2D. Conversely, gene expression of WNT5A (p=0.0232), SOST (p<0.0001), and GSK3B (p=0.0456) were higher, while collagen (COL1A1) was lower in T2D (p=0.0482). AGEs content was associated with SOST and WNT5A (r=0.9231, p<0.0001; r=0.6751, p=0.0322), but inversely correlated with LEF-1 and COL1A1 (r=-0.7500, p=0.0255; r=-0.9762, p=0.0004). SOST was associated with glycemic control and disease duration (r=0.4846, p=0.0043; r=0.7107, p=0.00174), whereas WNT5A and GSK3B were only correlated with glycemic control (r=0.5589, p=0.0037; r=0.4901, p=0.0051). Finally, Young's modulus was negatively correlated with SOST (r=-0.5675, p=0.0011), AXIN2 (r=-0.5523, p=0.0042), and SFRP5 (r=-0.4442, p=0.0437), while positively correlated with LEF-1 (r=0.4116, p=0.0295) and WNT10B (r=0.6697, p=0.0001). These findings suggest that Wnt signaling and AGEs could be the main determinants of bone fragility in T2D.

Bone canonical Wnt signaling is downregulated in type 2 diabetes and associates with higher advanced glycation end-products (AGEs) content and reduced bone strength

Type 2 diabetes (T2D) is associated with higher fracture risk, despite normal or high bone mineral density. We reported that bone formation genes (SOST and RUNX2) and advanced glycation end-products (AGEs) were impaired in T2D. We investigated Wnt signaling regulation and its association with AGEs accumulation and bone strength in T2D from bone tissue of 15 T2D and 21 non-diabetic postmenopausal women undergoing hip arthroplasty. Bone histomorphometry revealed a trend of low mineralized volume in T2D (T2D 0.249% [0.156–0.366]) vs non-diabetic subjects 0.352% [0.269–0.454]; p=0.053, as well as reduced bone strength (T2D 21.60 MPa [13.46–30.10] vs non-diabetic subjects 76.24 MPa [26.81–132.9]; p=0.002). We also showed that gene expression of Wnt agonists LEF-1 (p=0.0136) and WNT10B (p=0.0302) were lower in T2D. Conversely, gene expression of WNT5A (p=0.0232), SOST (p&lt;0.0001), and GSK3B (p=0.0456) were higher, while collagen (COL1A1) was lower in T2D (p=0.0482). AGEs content was associated with SOST and WNT5A (r=0.9231, p&lt;0.0001; r=0.6751, p=0.0322), but inversely correlated with LEF-1 and COL1A1 (r=–0.7500, p=0.0255; r=–0.9762, p=0.0004). SOST was associated with glycemic control and disease duration (r=0.4846, p=0.0043; r=0.7107, p=0.00174), whereas WNT5A and GSK3B were only correlated with glycemic control (r=0.5589, p=0.0037; r=0.4901, p=0.0051). Finally, Young’s modulus was negatively correlated with SOST (r=−0.5675, p=0.0011), AXIN2 (r=−0.5523, p=0.0042), and SFRP5 (r=−0.4442, p=0.0437), while positively correlated with LEF-1 (r=0.4116, p=0.0295) and WNT10B (r=0.6697, p=0.0001). These findings suggest that Wnt signaling and AGEs could be the main determinants of bone fragility in T2D.

Advanced Glycation Endproducts: A Marker of Long-term Exposure to Glycemia.

This article examines the importance of advanced glycation endproducts (AGEs) and summarizes the structure of AGEs, pathological changes associated with AGEs, the contribution of AGEs to metabolic memory, and the value of AGEs as a predictor of diabetic complications and cardiovascular disease in people with and without diabetes. As a practical focus, skin autofluorescence (SAF) is examined as an attractive approach for estimating AGE burden. The measurement of AGEs may be of significant value to specific individuals and groups, including Black and Hispanic/Latino Americans, as they appear to have higher concentrations of hemoglobin A1c (HbA1c) than would be predicted by other metrics of mean glycemia. We hypothesize that if the amount of glycation of HbA1c is greater than expected from measured glucose levels, and if AGEs are accumulating, then this accumulation of AGEs might account for the increased rate of complications of diabetes in populations with high rates of vascular disease and other complications. Thus, identifying and modifying the burden of AGEs based on measurement of AGEs by SAF may turn out to be a worthwhile metric to determine individuals who are at high risk for the complications of diabetes as well as others without diabetes at risk of vascular disease. We conclude that available evidence supports SAF as both a clinical measurement and as a means of evaluating interventions aimed at reducing the risks of vascular disease and diabetic complications.

Abstract 5410: Unveiling PAI-1 as a new player in chemoresistant melanoma in aged human skin reconstructed in vitro

Abstract The impact of advanced glycation end products (AGEs) accumulation is associated with the development and exacerbation of many degenerative processes and disorders, including aging and cancer. AGEs accumulation in the skin leads to stiffness and loss of elasticity by building up in the connective tissue during aging process. This process has implications of the extracellular matrix, affecting the adhesion, migration, and invasiveness potential of melanoma cells. Furthermore, tumor invasiveness is correlated with mechanical stiffness, contributing to the high metastatic capacity of melanoma. To address this research gap, our study aimed to evaluate the invasive potential of chemoresistant melanoma using an in vitro model of reconstructed aged human skin modified by glycation. Glycated skin exhibited distinct features indicative of aging, including positive pentosidine fluorescence and elevated CML labeling and expression, well-established biomarkers of aging. Furthermore, glycated skin with resistant melanoma demonstrated reduced expression of differentiated keratinocytes (CK-10) and increased expression of undifferentiated keratinocytes (CK-14). Overall, in glycated skin with resistant melanoma, decreased proliferation and increased tumor invasion were observed, associated with changes in the expression of key markers, such as reduced MITF and SOX-10 and increased AXL. Downregulation of MITF in skin with resistant melanoma resulted in decreased Melan-A expression, implying altered pigmentation of melanoma cells. Additionally, resistant melanoma in glycated skin showed enhanced inflammation, as indicated by higher levels of IL-8 and IL-1α. Gene screening showed upregulation of the PAI-1, ABL-1, COL1A1, SPARC genes. Among these genes, PAI-1 (Plasminogen activator inhibitor-1) was upregulated in resistant melanoma compared to naïve melanoma both in glycated skin. PAI-1 may play a critical role in the development of aging-associated pathological changes. In addition, PAI-1 is recognized as a marker of senescence and a key member of a group of proteins collectively known as the senescence-messaging secretome. It also performs protumorigenic functions, such as promoting vasculature, increasing growth, motility and protecting tumor cell apoptosis. Overall, this work demonstrated that skin aged by glycation when associated with i-Braf resistant melanoma exhibited a more invasive and less proliferative profile (low MITF and SOX10, elevated AXL), more inflammatory (elevated IL-8 and IL-1α) and with a greater number of immature keratinocytes (elevated ck-14). PAI-1 overexpression may be a promising target to expand studies caused by oncogenes in the model of aged skin by glycation with resistant melanoma. Citation Format: Renaira Oliveira da Silva, Larissa A. Carvalho, Denisse E. Camarena, Julia R. Silva, Isabella H. Noma, Manoel O. Moraes, Paula C. Pennacchi, Silvya S. Maria Engler. Unveiling PAI-1 as a new player in chemoresistant melanoma in aged human skin reconstructed in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5410.

Novel insights into RAGE signaling pathways during the progression of amyotrophic lateral sclerosis in RAGE-deficient SOD1 G93A mice.

Amyotrophic lateral sclerosis (ALS) is neurodegenerative disease characterized by a progressive loss of motor neurons resulting in paralysis and muscle atrophy. One of the most prospective hypothesis on the ALS pathogenesis suggests that excessive inflammation and advanced glycation end-products (AGEs) accumulation play a crucial role in the development of ALS in patients and SOD1 G93A mice. Hence, we may speculate that RAGE, receptor for advanced glycation end-products and its proinflammatory ligands such as: HMGB1, S100B and CML contribute to ALS pathogenesis. The aim of our studies was to decipher the role of RAGE as well as provide insight into RAGE signaling pathways during the progression of ALS in SOD1 G93A and RAGE-deficient SOD1 G93A mice. In our study, we observed alternations in molecular pattern of proinflammatory RAGE ligands during progression of disease in RAGE KO SOD1 G93A mice compared to SOD1 G93A mice. Moreover, we observed that the amount of beta actin (ACTB) as well as Glial fibrillary acidic protein (GFAP) was elevated in SOD1 G93A mice when compared to mice with deletion of RAGE. These data contributes to our understanding of implications of RAGE and its ligands in pathogenesis of ALS and highlight potential targeted therapeutic interventions at the early stage of this devastating disease. Moreover, inhibition of the molecular cross-talk between RAGE and its proinflammatory ligands may abolish neuroinflammation, gliosis and motor neuron damage in SOD1 G93A mice. Hence, we hypothesize that attenuated interaction of RAGE with its proinflammatory ligands may improve well-being and health status during ALS in SOD1 G93A mice. Therefore, we emphasize that the inhibition of RAGE signaling pathway may be a therapeutic target for neurodegenerative diseases.

Inhibition of Advanced Glycation End Products and NADPH Oxidase by Cirsium japonicum in Streptozotocin-Induced Diabetic Rats

Advanced glycation end-products (AGEs) and their receptor cause diabetic liver disease by increasing oxidative stress and inflammation. We investigate the potential therapeutic benefits of Cirsium japonicum (CJ) in preventing the progression of diabetes, focusing on complications for both liver and kidney health associated with AGEs. Streptozotocin (STZ, 30 mg/kg) was injected into SD rats and CJ (50, 100 mg/kg) was orally administered for 4 weeks. CJ treatment led to a marked reduction in key diabetic markers (glucose, reaction oxygen species, and lactate dehydrogenase), compared with the rats treated only with STZ. Moreover, the hepatic tissues of STZ-treated rats exhibited heightened biomarkers associated with AGE induction and formation, and these were notably attenuated in the CJ-treated rats. This effectively alleviated oxidative stress, inflammation, and AGE accumulation in the liver. Similarly, in the context of diabetic nephropathy, CJ treatment resulted in significant improvements in the rats with STZ-induced diabetes. Biomarkers associated with AGE induction and formation were significantly reduced in CJ-treated rats, demonstrating the ability of CJ to combat renal oxidative stress, inflammation, and AGE-related complications in diabetic nephropathy. CJ thus shows potential as a promising natural remedy that might mitigate the detrimental effects of diabetes on both the liver and kidneys through its anti-oxidation, anti-inflammation, and anti-AGE activities. These findings suggest that CJ is a beneficial agent for preventing and treating diabetic complications.

Inhibition of fluorescent advanced glycation end-products by ferulic acid and chlorogenic acid: A fluorescence spectroscopy and molecular docking study

The effects of ferulic acid (FA) and chlorogenic acid (CGA) on fluorescent advanced glycation end-products (fAGEs) were investigated through the Maillard reaction. Model systems were incubated with different concentrations (0, 10, 20, 40, 80, and 160 μg/mL) of FA or CGA at 55 °C for 12 h, and fluorescence intensity of advanced glycation end-products (AGEs) was measured. After adding 160 μg/mL FA and CGA, the fluorescence intensity of AGEs was suppressed by 15.988% ± 0.556% and 16.544% ± 0.275%, respectively (P < 0.05). Compared with control group, free amino groups levels were the highest in model systems containing 160 μg/mL FA (0.096 ± 0.011 mg l-leucine equivalent/mL) and CGA (0.130 ± 0.000 mg l-leucine equivalent/mL) (P < 0.05). Carbonyls content decreased in a dose-dependent fashion with increasing concentrations of FA and CGA (P < 0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results demonstrated that FA and CGA could impede the generation of bovine serum albumin (BSA)-glucose cross-linking substances. Spectroscopy results indicated that the binding constant of BSA-CGA was higher than that of BSA-FA. Meanwhile, molecular docking results suggested that the binding affinity of CGA to BSA was greater than to FA. These results suggested that CGA had a stronger inhibitory effect on the fluorescence intensity of AGEs. Therefore, FA and CGA may be potent natural antioxidants in mitigating the accumulation of AGEs during food thermal processing.

From hyperglycemia to intervertebral disc damage: exploring diabetic-induced disc degeneration.

The incidence of lumbar disc herniation has gradually increased in recent years, and most patients have symptoms of low back pain and nerve compression, which brings a heavy burden to patients and society alike. Although the causes of disc herniation are complex, intervertebral disc degeneration (IDD) is considered to be the most common factor. The intervertebral disc (IVD) is composed of the upper and lower cartilage endplates, nucleus pulposus, and annulus fibrosus. Aging, abnormal mechanical stress load, and metabolic disorders can exacerbate the progression of IDD. Among them, high glucose and high-fat diets (HFD) can lead to fat accumulation, abnormal glucose metabolism, and inflammation, which are considered important factors affecting the homeostasis of IDD. Diabetes and advanced glycation end products (AGEs) accumulation- can lead to various adverse effects on the IVD, including cell senescence, apoptosis, pyroptosis, proliferation, and Extracellular matrix (ECM) degradation. While current research provides a fundamental basis for the treatment of high glucose-induced IDD patients. further exploration into the mechanisms of abnormal glucose metabolism affecting IDD and in the development of targeted drugs will provide the foundation for the effective treatment of these patients. We aimed to systematically review studies regarding the effects of hyperglycemia on the progress of IDD.

Matrix viscoelasticity promotes liver cancer progression in the pre-cirrhotic liver.

Type 2 diabetes mellitus is a major risk factor for hepatocellular carcinoma (HCC). Changes in extracellular matrix (ECM) mechanics contribute to cancer development1,2, and increased stiffness is known to promote HCC progression in cirrhotic conditions3,4. Type 2 diabetes mellitus is characterized by an accumulation of advanced glycation end-products (AGEs) in the ECM; however, how this affects HCC in non-cirrhotic conditions is unclear. Here we find that, in patients and animal models, AGEs promote changes in collagen architecture and enhance ECM viscoelasticity, with greater viscous dissipation and faster stress relaxation, but not changes in stiffness. High AGEs and viscoelasticity combined with oncogenic β-catenin signalling promote HCC induction, whereas inhibiting AGE production, reconstituting the AGE clearance receptor AGER1 or breaking AGE-mediated collagen cross-links reduces viscoelasticity and HCC growth. Matrix analysis and computational modelling demonstrate that lower interconnectivity of AGE-bundled collagen matrix, marked by shorter fibre length and greater heterogeneity, enhances viscoelasticity. Mechanistically, animal studies and 3D cell cultures show that enhanced viscoelasticity promotes HCC cell proliferation and invasion through an integrin-β1-tensin-1-YAP mechanotransductive pathway. These results reveal that AGE-mediated structural changes enhance ECM viscoelasticity, and that viscoelasticity can promote cancer progression in vivo, independent of stiffness.

Localization of advanced glycation end-products and their receptor in tendinopathic lesions.

This study was designed to investigate the accumulation of advanced glycation end-products (AGEs) and the expression of the receptor of AGEs (RAGE) in tendinopathic tissues. In this study, tendinopathic posterior tibial tendons (PTT) were collected from patients (n=6). Redundant autografts of flexor digitorum longus tendon (FDL; n=3) were used for controls. The control and tendinopathic tendon tissues were used for extraction of proteins for western blot and sectioned for histology and immunohistochemistry. Tendinopathy of the PTT was confirmed histologically by the presentation of disorderly organized collagen fibers, high cellularity and increased vascularity. By immunohistochemistry, heterogeneous accumulation of AGEs was detected on the PTT sections and concentrated in areas, where collagen fibers were disorderly and tangled. In the PTT, roundish tenocytes were also AGEs-positive. In contrast, AGEs were diffuse, lightly stained in the FDL. A greater number of tenocytes within the tendinopathic lesions in the PTT were RAGE positive, compared to the tenocytes in the FDL. Western blot confirmed the expression of AGEs and RAGE in both tendinopathic PTT and control FDL but their band densities were not significantly different. The spatial relation of the accumulated AGEs and RAGE- positive tenocytes within the tendinopathic lesions indicates their involvement in the molecular pathology of tendinopathy.

Dietary Intake of Fructooligosaccharides Protects against Metabolic Derangements Evoked by Chronic Exposure to Fructose or Galactose in Rats.

Diets rich in fat and sugars evoke chronic low-grade inflammation, leading to metabolic derangements. This study investigates the impact of fructose and galactose, two commonly consumed simple sugars, on exacerbation of the harmful effects caused by high fat intake. Additionally, the potential efficacy of fructooligosaccharides (FOS), a fermentable dietary fiber, in counteracting these effects is examined. Male Sprague-Dawley rats (six/group) are fed 8 weeks as follows: control 5% fat diet (CNT), 20% fat diet (FAT), FAT+10% FOS diet (FAT+FOS), FAT+25% galactose diet (FAT+GAL), FAT+GAL+10% FOS diet (FAT+GAL+FOS), FAT+25% fructose diet (FAT+FRU), FAT+FRU+10% FOS diet (FAT+FRU+FOS). The dietary manipulations tested do not affect body weight gain, blood glucose, or markers of systemic inflammation whereas significant increases in plasma concentrations of triacylglycerols, cholesterol, aspartate aminotransferase, and alanine aminotrasferase are detected in both FAT+FRU and FAT+GAL compared to CNT. In the liver and skeletal muscle, both sugars induce significant accumulation of lipids and advanced glycation end-products (AGEs). FOS supplementation prevents these impairments. This study extends the understanding of the deleterious effects of a chronic intake of simple sugars and demonstrates the beneficial role of the prebiotic FOS in dampening the sugar-induced metabolic impairments by prevention of lipid and AGEs accumulation.

How dietary advanced glycation end products could facilitate the occurrence of food allergy

BackgroundFood allergy (FA) is one of the most common chronic conditions in the pediatric age with an increasing prevalence under the pressure of environmental factors in predisposed individuals. It has been hypothesized that the increased consumption of ultra-processed foods, containing high levels of dietary advanced glycation end-products (AGEs), could facilitate the occurrence of food allergy. ObjectiveHere we provide preclinical and clinical evidence on the potential role of AGEs in facilitating the occurrence of FA. MethodsHuman enterocytes, human small intestine organ culture, and peripheral mononuclear blood cells (PBMCs) from children at risk for allergy were used to investigate the direct effect of AGEs on gut barrier, inflammation, Th2 cytokines response and mitochondrial function.The intake of the three most commonly glycation products in Western diet-foods Nε -(carboxymethyl) lysine (CML), Nε -(1-carboxyethyl) lysine (CEL), and Nδ -(5-hydro-5- methyl-4-imidazolon-2-yl)-ornithine (MG-H1), and the skin AGEs accumulation were comparatively investigated in children with FA and in age-matched healthy controls. ResultsHuman enterocytes exposed to AGEs showed alteration in gut barrier, AGEs receptor expression, reactive oxygen species production and autophagy, with increased transepithelial passage of food antigens. Small intestine organ culture exposed to AGEs showed an increase of CD25+ cells and proliferating crypt enterocytes. PBMCs exposed to AGEs showed alteration in proliferation rate, AGEs receptor activation, release of inflammatory and Th2 cytokines, and mitochondrial metabolism.Significant higher dietary AGEs intake and skin accumulation were observed in FA children (n=42) compared with age-matched healthy controls (n=66). ConclusionsThese data, supporting a potential role for dietary AGEs in facilitating the occurrence of FA, suggest the importance of limiting the AGEs exposure in the pediatric age as potential preventive strategy against this common condition.

N-acetyl-L-hydroxyproline - A potent skin anti-ageing active preventing advanced glycation end-product formation invitro and exvivo.

Advanced glycation end-products (AGEs) represent a large group of compounds generated by a non-enzymatic reaction between reducing sugars and amino groups. The formation and accumulation of AGEs in the skin lead to protein crosslinking, dermal stiffening and yellowing, which ultimately contribute to cutaneous ageing. Amino acids have been described to exhibit anti-glycation effects. The objective of this study was to understand the inhibitory role of the amino acid derivative N-acetyl-L-hydroxyproline (NAHP) as an anti-glycation active for human skin. A cell-free assay investigating the inhibition of glycation of serum albumin by NAHP was used to determine the capability of NAHP to decrease AGE formation. Also, by assessing the amount of the AGE N-(carboxymethyl)lysine (CML) the anti-glycation abilities of NAHP were investigated utilizing dot blot analysis. The improvement of cell-matrix interaction by NAHP was determined invitro using a glycated fibroblast-populated collagen lattice (FPCL) dermis model. In skin biopsies, AGE autofluorescence was determined after treatment with NAHP and/or glucose exvivo. NAHP significantly and dose-dependently inhibited levels of AGEs, which were induced by the glycation of a protein solution. This decrease could be visualized by showing that the brownish appearance as well as the AGE-specific fluorescence of glucose-treated samples were reduced after the application of increasing amounts of NAHP. Also, CML formation was dose-dependently inhibited by NAHP. In FPCLs, the contractile capacity of fibroblasts was significantly disturbed after glycation. This could be prevented by the addition of NAHP. Compared to glyoxal-treated samples, the co-application of NAHP significantly decreased the diameter as well as the weight of glycated FPCLs. Exvivo application of glucose to skin explants showed a higher AGE fluorescence signal compared to control explants. Co-treatment with NAHP and glucose decreased the level of AGE fluorescence in comparison to glucose-treated explants. These data provide clear evidence that under glycation stress conditions treatment with NAHP inhibited AGE formation invitro and exvivo and prevented the loss of cellular contractile forces in a glycated dermis model. Thus, NAHP obviously provides a beneficial treatment option to counteract AGE-related changes in human skin such as dermal stiffening and yellowish skin appearance.

Different Effects of High-Fat/High-Sucrose and High-Fructose Diets on Advanced Glycation End-Product Accumulation and on Mitochondrial Involvement in Heart and Skeletal Muscle in Mice

Diets with an elevated content of fat, sucrose, or fructose are recognized models of diet-induced metabolic alterations, since they induce metabolic derangements, oxidative stress, and chronic low-grade inflammation associated with local and systemic accumulation of advanced glycation end-products (AGEs). This study used four-week-old C57BL/6 male mice, randomly assigned to three experimental dietary regimens: standard diet (SD), high-fat high-sucrose diet (HFHS), or high fructose diet (HFr), administered for 12 weeks. Plasma, heart, and tibialis anterior (TA) skeletal muscle were assayed for markers of metabolic conditions, inflammation, presence of AGEs, and mitochondrial involvement. The HFHS diet induced a tissue-specific differential response featuring (1) a remarkable adaptation of the heart to HFHS-induced heavy oxidative stress, demonstrated by an increased presence of AGEs and reduced mitochondrial biogenesis, and efficaciously counteracted by a conspicuous increase in mitochondrial fission and PRXIII expression; (2) the absence of TA adaptation to HFHS, revealed by a heavy reduction in mitochondrial biogenesis, not counteracted by an increase in fission and PRXIII expression. HFr-induced mild oxidative stress elicited tissue-specific responses, featuring (1) a decrease in mitochondrial biogenesis in the heart, likely counteracted by a tendency for increased fission and (2) a mild reduction in mitochondrial biogenesis in TA, likely counteracted by a tendency for increased fusion, showing the adaptability of both tissues to the diet.

Abstract 16373: Pyridoxamine (Vitamin B6) Mitigation of Protein Glycation and Deleterious Platelet-Material Interactions in Bioprosthetic Heart Valve Leaflets

Introduction: Though bioprosthetic heart valves (BHV) most often do not require anticoagulation, it has been reported that 12% of BHVs have significant leaflet thrombosis. We identified Vitamin B6 (pyridoxamine, abbr. PYR) as a pretreatment agent to reduce advanced glycation end-product (AGE) accumulation within bovine pericardial (BP) BHVs. AGEs contribute to valvular degeneration through collagen crosslinking and immune signaling. PYR is also known to inhibit platelet aggregation. Hypothesis: PYR pretreatment and supplementation mitigate BHV thrombosis. Methods: Glutaraldehyde fixed collagen coated (GFC) PVC tubing was used as a leaflet surface model and methylglyoxal (MGO) pretreatment to simulate glycation. PYR pretreated collagen surfaces and perfusate PYR supplementation were compared to untreated controls. These studies were repeated with glycated GFC. Fresh citrated human whole blood from healthy donors was perfused over the surfaces for 4 hours at 37 °C and arterial shear using the Chandler loop apparatus. Post perfusion platelet activation (CD62P expression via flow cytometry) and nitric oxide synthase (NOS) activity were measured. Platelets adhered to the tubing sections were visualized and quantitated via scanning electron microscopy. Results: PYR pretreatment of GFC surfaces reduced platelet activation after perfusion compared to the control (Fig1a). Surface glycation with MGO resulted in increased platelet activation, but PYR pretreatment of the glycated surface mitigated the effect of glycation on platelet activation (Fig1b). NOS activity was impaired by surface glycation and PYR treatment appears to rescue function in glycated environments (Fig1c). Platelet adhesion to GFC was increased by glycation (Fig1d-f). Conclusions: Glycated surfaces, even in euglycemia, are prothrombotic when compared to non-glycated surfaces. Vitamin B6 reduces platelet activation and adhesion in both glycated and non-glycated environments.

Innovative Wound Dressing Coated with Drug-Loaded Adipose Mesenchymal Stem Cells to Promote Wound Healing in Diabetes

Impaired wound healing is associated with hyperglycaemia in patients with diabetes. Hyperglycaemia induces protein glycation and the formation of Advanced Glycation End-Products (AGEs). The accumulation of AGEs in the body results in the structural and functional modification of tissue proteins. This study was conducted to evaluate compounds with antiglycation activities (S-Ally1 Cysteine (SAC), N-Acetylcysteine (NAC) and the mimic compound A). The extent of glycation in the presence and absence of several inhibitors was assessed via several methods including fluorescence, Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE)- silver stain, Western blotting, and Enzyme-Linked Immunosorbent Assays (ELISA). Additionally, this research aimed to evaluate and quantify the potential of Human Adipose Mesenchymal Stem Cells (hADMSCs) to uptake and release these drugs as potential therapeutics. To achieve this, hADMSCs were primed with a combination of SAC/NAC and mimic compound A and their concentrations were analysed using High-Performance Liquid Chromatography (HPLC). The SAC/NAC and mimic compound A prohibit the formation of AGEs while the Conditioned Medium (CM) from SAC/NACand compound A-loaded hADMSCs induced cell migration and tube formation in BAECs. hADMSCs provide a unique opportunity for the development of an innovative targeting and drug-delivery system which could effectively deliver therapeutics to specific regions of wounds or other damaged tissues. The data provided demonstrate the potential of hADMSCs as a drug delivery method with the potential to improve wound healing, and it may offer potential therapeutic targeting for the development of diabetic complications.

Effect of in vitro ribosylation on the dynamic fracture behavior of mature bovine cortical bone

In this study, the fracture behavior of ribosylated bovine cortical bone is investigated under loading conditions simulating a fall event. Single edge notched specimens, separated into a control group (n = 11) and a ribosylated group (n = 8), were extracted from the mid-diaphysis of a single bovine femur harvested from a mature cow. A seven-day ribosylation process results in the accumulation of Advanced-Glycation End Products (AGEs) cross-links and AGE adducts. Specimens were subjected to symmetric three point bending (opening mode) and an impact velocity of 1.6 m/s using a drop tower. Near-crack displacement fields up to fracture initiation are determined from high-speed images post-processed using digital image correlation. A constrained over-deterministic least squares regression and orthotropic material linear elastic fracture mechanics theory are used to extract the in-plane critical stress intensity factors at fracture initiation (i.e., fracture initiation toughness values). Statistically significant differences were not observed when comparing the in-plane fracture initiation toughness values (p≥0.96) or energy release rate (p=0.90) between the control and seven-day ribosylated groups. The intrinsic variability of bone may require high sample numbers in order to achieve an adequately powered experiment when assessing dynamic fracture behavior. While there are no detectable differences due to the ribosylation treatment investigated, this is likely due to the limited sample sizes utilized.

OR13-01 Type 1 Diabetes Is Associated With Differential Skeletal Effects At The Onset Of Peak Bone Accrual

Abstract Disclosure: A.V. Brossfield: None. K.M. Williams: None. A.B. Sopher: None. D.J. McMahon: None. J. Fernando: None. S. Agarwal: None. M.R. Rubin: None. Objective: Type 1 diabetes (T1D) often develops prior to attainment of peak bone mass, yet few data exist regarding bone accretion in the peri-pubertal period. We hypothesized that T1D have disrupted bone architecture at the onset of peak bone mass accrual in association with hyperglycemia and advanced glycation endproduct (AGE) accumulation. Methods: We enrolled T1D and controls at onset of peak bone accretion (Tanner: girls 2/3, boys 3/4) and assessed aBMD by DXA and volumetric BMD (vBMD), microarchitecture, and bone strength by high resolution peripheral quantitative computed tomography (HRpQCT) with finite element analysis (µFE) at the distal (4%) and proximal (30%) radius and tibia. We assessed time in hyperglycemia (&amp;gt;180 mg/dL) by continuous glucose monitoring and AGE accumulation by skin autofluorescence (SAF). Results: T1D (n=29, age 12.5 ± 0.3 [SE] yr, 79% male, 68% white) vs controls (n=31, 12.2 ± 0.3 yr, 55% male, 68% white) had higher BMI (21.3 ± 1 vs 18.4 ± 0.5 kg/m2; p=0.04), fasting glucose (168.5 ± 9 vs 88.4 ± 2 mg/dL; p&amp;lt;0.0001) and HbA1c (8.4 ± 0.8 vs 5.0 ± 0.2%; p=0.05) with a trend toward higher bone age (13.5 ± 0.3 vs 12.6 ± 0.3 yr, p=0.07) and lower 25OHD (24.0 ± 1 vs 34.8 ± 3 ng/mL, p=0.08). After multivariate adjustment (sex, bone age, height and weight), DXA showed decreased bone area in T1D at the total, sub-total, leg, rib and ultradistal radius, and decreased bone mineral content at the rib, leg and trochanter (ranging from -4.1% to -13.5%, all p &amp;lt;0.05). Multivariate adjusted HRpQCT data showed decreased trabecular area in T1D at the distal radius (169.9 ± 8 vs 201.2 ± 8 mm2; p=0.007) and tibia (578 ± 17 vs 631 ± 17 mm2; p=0.04) and decreased cortical perimeter at the distal radius (56.0 ± 1 vs 60.1 ± 1 mm2; p=0.009). However, T1D had increased cortical vBMD at the distal (698.2 ± 8 vs 663.5 ± 8 mg HA/cm3; p=0.004) and proximal radius (998 ± 6 vs 977 ± 6 mg HA/cm3; p=0.02) and tibia (998 ± 6 vs 977 ± 6 mg HA/cm3; p=0.02) and increased cortical thickness at the distal radius (0.74 ± 0.03 vs 0.64 ± 0.03 mm; p=0.03). There was no difference in bone strength by µFE. Within T1D, lower trabecular area at the distal radius was associated with higher SAF (β -69.26 ± 30 mm2; p=0.04) while higher cortical vBMD at the distal tibia was associated with higher time in hyperglycemia (β 0.633 ± 0.3 mg HA/cm3; p=0.03). Conclusion: T1D at the onset of peak bone accrual have decreased bone area and mineral content by DXA. They also have decreased trabecular area but increased cortical vBMD by HRpQCT, in association with AGE accumulation and hyperglycemia. We speculate that reduced bone turnover with hyperglycemia might lead to reduced area at more metabolically active trabecular sites but is compensated for by excess mineral accumulation at less active cortical sites, with overall maintenance of bone strength. Follow up will elucidate progression of these alterations during the growth spurt. Presentation: Friday, June 16, 2023

Role of advanced glycation endproducts in bone fragility in type 1 diabetes

The excess fracture risk observed in adults with type 1 diabetes (T1D) is inexplicable in the presence of only modest reductions in areal bone mineral density (BMD). Accumulation of advanced glycation endproducts (AGEs) in bone has been invoked as one explanation for the increased bone fragility in diabetes. The evidence linking AGEs and fractures in individuals with T1D is sparse, although the association has been observed in individuals with type 2 diabetes. Recent data show that in T1D, AGEs as measured by skin intrinsic fluorescence, are a risk factor for lower BMD. Further research in T1D is needed to ascertain whether there is a causal relationship between fractures and AGEs. If confirmed, this would pave the way for finding interventions that can slow AGE accumulation and thus reduce fractures in T1D.