Advanced glycation end-products: a review

A comprehensive review of scientifically reported phytochemicals to manage allodynia in chronic diabetes complications

BACKGROUND

The global prevalence of diabetes mellitus and its associated complications is increasing, impacting both developed and developing nations. One common complication is neuropathy and neuropathic pain, which often manifests as symptoms such as allodynia-a condition where patients experience pain from non-painful stimuli.

OBJECTIVE

This review seeks to explore scientifically validated medicinal plants and phytochemicals, presenting the findings in an organized format based on published literature.

METHODOLOGY

Data were searched in pubmed literature and only the scientifically reported phytochemicals were considered to include in this review.

KEY FINDINGS

The U.S. Food and Drug Administration (FDA) has not approved many medications targeting the root causes of neuropathy. Instead, various strategies are employed to manage the symptoms of allodynia. Research on plant-based ethno-pharmaceuticals aims to address the symptoms without affecting the disease's progression, which involves the gradual loss of nerve fibres from the extremities. This article delves into allodynia's different forms, implications, and underlying signalling mechanisms.

CONCLUSION

The hope is that further research on phytochemicals could lead to the development of therapies for managing various forms of allodynia in diabetic patients.

Serum zinc concentration and history of isCGM contact dermatitis in type 1 diabetes

BACKGROUND

In insulin treatment for type 1 diabetes, intermittent scanning continuous glucose monitoring (isCGM: FreeStyle® Libre), in which a sensor is adhered to the skin, is often used to monitor blood glucose fluctuations and manage glucose levels. Zinc-deficient skin is reportedly more susceptible to primary irritant rashes. This study investigated whether zinc deficiency is associated with a history of contact dermatitis caused by isCGM in patients with type 1 diabetes.

METHODS

The subjects comprised 55 patients (23 men, 32 women, age 57.9 ± 17.6 years) with type 1 diabetes who were outpatients at our department and had a history of isCGM use. We examined the history of contact dermatitis due to isCGM in relation to serum zinc concentration.

RESULTS

Serum zinc was significantly lower in those with history of contact dermatitis (23 subjects) compared to those without (32 subjects) (P = 0.033). History of contact dermatitis due to isCGM was negatively associated with both age (β =  - 0.266, P = 0.040) and zinc deficiency category (β =  - 0.315, P = 0.017).

CONCLUSIONS

For people undergoing treatment for type 1 diabetes for whom skin problems caused by isCGM are a barrier to glucose management, screening of serum zinc concentration may be important.

Mechanistic insights into advanced glycation end products production in glucose-lysine model system involved with ascorbic acid

Ascorbic acid (AA), despite being an essential vitamin, is also a potential precursor to form advanced glycation end products (AGEs) in heat-processed foods. The dual action of AA (act as an inhibitor and a precursor concurrently) in AGEs formation in glucose (Glu)-lysine (Lys) model system has been found in our previous study. However, the mechanism underlying the dual role of AA has not been elucidated. This study clarified that AA, when acting as an inhibitor, primarily suppresses AGEs formation via its pH-regulating capacity rather than its reductive (free radical scavenging) potential. When AA serves as a substrate, its reactivity to form AGEs depends on pH condition. We further elucidated the primary pathways of AA-mediated AGEs formation. Methylglyoxal (MGO), generated via 2,3-diketoglucose (2,3-DKG), remains the principal intermediate for CEL formation from AA. Xylosone, a highly reactive carbonyl compound derived from AA, emerges as the major intermediate for CML formation.

Zn-Based Multi-Active Framework Nanoparticles TSA-CAN-Zn Inhibit Skin Glycation via Dual Blockade of HMGB1/RAGE and AGEs/RAGE Pathways

Receptor for advanced glycation end products (RAGE) plays an important role in skin glycation damage. High-mobility group 1B protein (HMGB1) and advanced glycation end products (AGEs) are key RAGE ligands. Simultaneous inhibition of HMGB1/RAGE and AGEs/RAGE pathways maybe an effective strategy to alleviate glycation induced skin damage. In this work, Theasinensin A (TSA) is identified as the active molecule inhibiting HMGB1-RAGE interaction through molecular docking. To simultaneously suppress HMGB1/RAGE and AGEs/RAGE pathways, Zn-based multi-active framework nanoparticles TSA-CAN-Zn are designed, which contain TSA and the active molecule L-carnosine (CAN) that inhibits AGEs production. In vitro studies demonstrated that TSA-CAN-Zn have radical scavenging activity and AGEs formation inhibition activity. TSA-CAN-Zn can not only inhibit ROS accumulation, cell apoptosis, and inflammatory factors production induced by glycation in HaCaT cells but also enhanced the lysosomal degradation of AGEs. TSA-CAN-Zn also mitigated the damage caused by glycation in mouse skin glycation model. Single-cell RNA sequencing results revealed the impact of TSA-CAN-Zn on different cell types of skin tissue, especially the basal cells of the epidermal layer and inflammation-related macrophages. And pathway analysis revealed that TSA-CAN-Zn mainly influences the downstream pathways of RAGE. Collectively, TSA-CAN-Zn is a promising therapeutic candidate for ameliorating glycation-induced skin damage.

Accelerated Biological Aging in Exfoliation Glaucoma Assessed by Fundus-Derived Predicted Age and Advanced Glycation End Products

Glaucoma is an age-related neurodegenerative disease characterized by progressive optic nerve damage. Accelerated biological aging, assessed using predicted age derived from fundus images, may serve as a biomarker for glaucoma progression. This study aimed to examine fundus-derived age acceleration among patients with primary open-angle glaucoma (POAG), exfoliation glaucoma (EXG), and controls, and to explore its biochemical basis through advanced glycation end products (AGEs). Fundus photographs from 237 participants (79 POAG, 79 EXG, and 79 age- and sex-matched controls) were analyzed using a deep learning model (EfficientNet) previously trained to predict biological age. AGE accumulation was assessed by measuring skin autofluorescence (sAF). Multivariate regression analyses were conducted to identify factors influencing predicted age acceleration, with stratification into age tertiles to control for age-related effects. EXG patients demonstrated significant accelerated biological aging compared to controls (p = 0.006), particularly evident in younger and middle-aged tertiles. AGE scores were significantly elevated in EXG relative to both POAG (p = 0.009) and control groups (p = 0.003). Predicted age and AGE scores were more strongly correlated than chronological age and AGEs, especially in the middle tertile (p = 0.002). Accelerated biological aging detected via fundus images occurs prominently in EXG, potentially reflecting underlying AGE accumulation. Fundus-derived predicted age could serve as a non-invasive biomarker for assessing glaucoma progression risk and warrants further exploration in clinical applications.

A Carbonyl-Trapping Mechanism-Based Automatic Mining (CTM-AM) Strategy for Accelerating the Discovery of Natural Products with Anti-Advanced Glycation End Products Activity

The abnormal accumulation of reactive dicarbonyl compounds, such as methylglyoxal, was a major trigger for the formation of advanced glycation end products (AGEs), which are closely associated with various diseases, including diabetic complications. Natural products are considered potentially effective candidates for preventing AGE formation. Given the complexity of natural resources, efficient tools for identifying natural AGE inhibitors in mixtures remain lacking. In this study, a carbonyl-trapping mechanism-based automatic mining (CTM-AM) strategy was developed, enabling the rapid identification of anti-AGE compounds from natural resources through liquid chromatography-high-resolution mass spectrometry (LC-HRMS) analysis. This workflow is based on the characteristics of the carbonyl-trapping reaction to identify the active peaks of candidate compounds, and subsequently applies the approach to 48 medicinal plant extracts. Structural annotation yielded 171 high-confidence active compounds, spanning 20 classes of natural products and encompassing a diverse array of reactive functional groups. The results demonstrated that this workflow enables the efficient identification of diverse carbonyl-trapping active compounds and their products in complex natural resources. This study provides an effective method and comprehensive information for discovering natural AGE inhibitors while also advancing the framework for mining bioactive compounds guided by reaction mechanisms.

Metformin attenuates endoplasmic reticulum stress in diabetic kidney disease: mechanistic insights and future perspectives

Diabetic kidney disease (DKD) is a common microvascular complication of diabetes that can lead to end-stage renal failure. Emerging evidence suggests that endoplasmic reticulum (ER) stress plays a crucial role in the pathogenesis of DKD by affecting various renal parenchymal cells, including endothelial cells, podocytes, and mesangial cells. This review comprehensively examines the relationship between ER stress and DKD, focusing on how metformin, a first-line antidiabetic medication, ameliorates ER stress-induced kidney injury. Multiple factors, including reactive oxygen species (ROS), proteinuria, and advanced glycation end products (AGEs), contribute to ER stress in DKD. Metformin's renoprotective effects are primarily mediated through activation of the AMPK signaling pathway, which modulates ER stress response, reduction of oxidative stress and its impact on ER function, and improvement of mitochondrial function. These mechanisms collectively lead to decreased proteinuria, reduced cell apoptosis, and attenuated epithelial-mesenchymal transition in diabetic kidneys. Understanding these molecular mechanisms provides new insights into the therapeutic potential of metformin in DKD treatment. However, further research is needed to elucidate the precise molecular pathways through which metformin regulates ER stress in different renal cell types under diabetic conditions.

Cognitive decline in older adults with type 2 diabetes: Unraveling site-specific glycoproteomic alterations

Type 2 diabetes (T2D) is consistently related to an increased risk of cognitive decline and dementia. However, the molecular underpinnings of this association remain poorly understood. In this study, we applied a novel mass spectrometry-based glycoproteomic methodology to profile serum glycoproteins in older adults with T2D, aiming to identify glycopeptiforms associated with cognitive impairment. Our method allowed comprehensive profiling of N glycosylation in addition to the unique ability to profile glycation events on specific amino acid sites. Serum samples from initially cognitively normal older adults with T2D were collected, with participants classified as cognitive decliners (who developed impairment) and non-decliners (who maintained normal cognition over time). We identified significant differences in the abundance of glycopeptiforms between these groups, noting that certain glycopeptiforms exhibited unique changes over time in decliners. We identified 13 glycopeptiforms that exhibited significant differences between the groups both at baseline and in their rates of change over time. Pathway analysis indicated that glycation events were linked to metabolic pathways while glycosylation to immune-related pathways, aligning with established links between these processes and cognitive decline. This study offers new insights into glycoproteoform alterations in older adults with T2D experiencing cognitive decline. It highlights the potential of specific glycopeptiforms as biomarkers for early cognitive impairment in T2D. Further validation in larger cohorts will enhance our understanding of glycosylation and glycation in T2D and potentially lead to the discovery of novel treatment targets for T2D-related cognitive decline. Raw data and search are available via ProteomeXchange with identifier PXD050780.

Depletion of natural killer cells enhances wound healing in diabetic mice

Natural killer cells are known for their killing function in infection- and tumor-related responses but also can shape immune responses involved in physiological processes such as wound healing. We recently reported that natural killer cells accumulate in skin wounds and express proinflammatory cytokines that may impede healing. Since impaired wound healing in diabetes is associated with persistent inflammation, the purpose of the present study was to determine whether natural killer cells contribute to impaired skin wound healing in diabetic mice. Here, we show that natural killer cells accumulate at higher levels in wounds in diabetic mice and exhibit less mature phenotypes compared to nondiabetic mice. In addition, local neutralization of CX3CL1 reduced natural killer cell accumulation in wounds of diabetic mice, suggesting that CX3CL1 plays a role in the infiltration of these cells to the wound site. Finally, depletion of natural killer cells in diabetic wounds improved reepithelization and collagen deposition, suggesting that the elevated levels of natural killer cells contribute to impaired healing associated with diabetes.

Identification and validation of poly-metabolite scores for diets high in ultra-processed food: An observational study and post-hoc randomized controlled crossover-feeding trial

BACKGROUND

Ultra-processed food (UPF) accounts for a majority of calories consumed in the United States, but the impact on human health remains unclear. We aimed to identify poly-metabolite scores in blood and urine that are predictive of UPF intake.

METHODS AND FINDINGS

Of the 1,082 Interactive Diet and Activity Tracking in AARP (IDATA) Study (clinicaltrials.gov ID NCT03268577) participants, aged 50-74 years, who provided biospecimen consent, n = 718 with serially collected blood and urine and one to six 24-h dietary recalls (ASA-24s), collected over 12-months, met eligibility criteria and were included in the metabolomics analysis. Ultra-high performance liquid chromatography with tandem mass spectrometry was used to measure >1,000 serum and urine metabolites. Average daily UPF intake was estimated as percentage energy according to the Nova system. Partial Spearman correlations and Least Absolute Shrinkage and Selection Operator (LASSO) regression were used to estimate UPF-metabolite correlations and build poly-metabolite scores of UPF intake, respectively. Scores were tested in a post-hoc analysis of a previously conducted randomized, controlled, crossover-feeding trial (clinicaltrials.gov ID NCT03407053) of 20 subjects who were admitted to the NIH Clinical Center and randomized to consume ad libitum diets that were 80% or 0% energy from UPF for 2 weeks immediately followed by the alternate diet for 2 weeks; eligible subjects were between 18-50 years old with a body mass index of >18.5 kg/m2 and weight-stable. IDATA participants were 51% female, and 97% completed ≥4 ASA-24s. Mean intake was 50% energy from UPF. UPF intake was correlated with 191 (of 952) serum and 293 (of 1,044) 24-h urine metabolites (FDR-corrected P-value < 0.01), including lipid (n = 56 serum, n = 22 24-h urine), amino acid (n = 33, 61), carbohydrate (n = 4, 8), xenobiotic (n = 33, 70), cofactor and vitamin (n = 9, 12), peptide (n = 7, 6), and nucleotide (n = 7, 10) metabolites. Using LASSO regression, 28 serum and 33 24-h urine metabolites were selected as predictors of UPF intake; biospecimen-specific scores were calculated as a linear combination of selected metabolites. Overlapping metabolites included (S)C(S)S-S-Methylcysteine sulfoxide (rs = -0.23, -0.19), N2,N5-diacetylornithine (rs = -0.27 for serum, -0.26 for 24-h urine), pentoic acid (rs = -0.30, -0.32), and N6-carboxymethyllysine (rs = 0.15, 0.20). Within the cross-over feeding trial, the poly-metabolite scores differed, within individual, between UPF diet phases (P-value for paired t test < 0.001). IDATA Study participants were older US adults whose diets may not be reflective of other populations.

CONCLUSIONS

Poly-metabolite scores, developed in IDATA participants with varying diets, are predictive of UPF intake and could advance epidemiological research on UPF and health. Poly-metabolite scores should be evaluated and iteratively improved in populations with a wide range of UPF intake.

Diabetic neuropathy: cutting-edge research and future directions

Diabetic neuropathy (DN) is a prevalent and debilitating complication of diabetes mellitus, significantly impacting patient quality of life and contributing to morbidity and mortality. Affecting approximately 50% of patients with diabetes, DN is predominantly characterized by distal symmetric polyneuropathy, leading to sensory loss, pain, and motor dysfunction, often resulting in diabetic foot ulcers and lower-limb amputations. The pathogenesis of DN is multifaceted, involving hyperglycemia, dyslipidemia, oxidative stress, mitochondrial dysfunction, and inflammation, which collectively damage peripheral nerves. Despite extensive research, disease-modifying treatments remain elusive, with current management primarily focusing on symptom control. This review explores the complex mechanisms underlying DN and highlights recent advances in diagnostic and therapeutic strategies. Emerging insights into the molecular and cellular pathways have unveiled potential targets for intervention, including neuroprotective agents, gene and stem cell therapies, and innovative pharmacological approaches. Additionally, novel diagnostic tools, such as corneal confocal microscopy and biomarker-based tests, have improved early detection and intervention. Lifestyle modifications and multidisciplinary care strategies can enhance patient outcomes. While significant progress has been made, further research is required to develop therapies that can effectively halt or reverse disease progression, ultimately improving the lives of individuals with DN. This review provides a comprehensive overview of current understanding and future directions in DN research and management.

The associations between skin advanced glycation end-products and Framingham cardiovascular risk in different age groups

Objective

Advanced glycation end-products (AGEs) may contribute to the pathogenesis of atherosclerotic cardiovascular disease (ASCVD), potentially influencing its development and progression differently at various life stages. This study aimed to elucidate the associations between AGEs and the risk of ASCVD across different age groups.

Methods

In this cross-sectional study, 1,240 subjects were enrolled and divided into three groups (Group Ⅰ, 20-39 years old, n = 468; Group Ⅱ, 40-59 years old, n = 471; Group Ⅲ, 60-79 years old, n = 301). Skin AGEs were measured by skin autofluorescence (SAF). ASCVD risk was assessed by a validated Framingham risk score calculator. Other proven ASCVD risk factors were also measured, including glycosylated hemoglobin, uric acid, lipid profile, homocysteine, and cystatin C.

Results

An increasing trend in skin AGEs was observed from Group Ⅰ to Group Ⅲ. Skin AGEs were significantly associated with ASCVD risk in all subjects (OR 1.029, 95% CI 1.003-1.056, P = 0.018), independent of some of the proven cardiovascular risk factors. This association was particularly significant in individuals aged 40-59 and 60-79 (OR = 1.047, 95% CI: 1.025-1.069; OR = 1.022, 95% CI: 1.002-1.042; both P < 0.05). ROC analysis showed that skin AGEs predicted the diagnosis of medium or high ASCVD risk in the pooled group, Group Ⅱ, and Group Ⅲ.

Conclusion

Our study substantiates that skin AGEs play an important role as an independent risk factor for ASCVD, highlighting their significance beyond traditional risk assessment models, particularly in middle-aged and older populations.

Preventive effects of thymoquinone on glyco-nitro-oxidized human fibrinogen: A comprehensive biophysical study projecting possible therapeutic role in diabetes and associated complications

Persistence of long-term hyperglycemia results in the glyco-oxidation of plasma proteins, which is considered to be a significant factor in metabolic dysfunction, linking hyperglycemia to the emergence of vascular complications. Methylglyoxal (MGO), a dicarbonyl species formed excessively under diabetes, elevates the oxidative stress, enhancing the generation of superoxide anion, which ultimately reacts with nitric oxide (NO•) to form peroxynitrite (PON). PON, being a powerful nitro-oxidizing agent distorts protein structure, hampering its function. This article describes the binding mechanism of thymoquinone (TQ) to fibrinogen (Fg) and its protective effects under simultaneous glyco-nitro-oxidation. Thermodynamic investigations revealed hydrogen bonding and Vander Waal interactions stabilise the complex, confirming its spontaneity and exothermic nature. TQ-induced micro-environmental and structural alterations in fibrinogen were observed by synchronous, 3-D fluorescence maps, and red edge excitation shift (REES). Molecular docking confirmed the wet lab experiments. Previous studies have shown that glycation, as well as nitro-oxidation, modifies the key residues of fibrinogen, leading to its aggregation. Our findings showed that TQ prevented MGO + PON-induced damage to fibrinogen. The current study analyzed the protective effects of TQ on glyco-nitro-oxidized fibrinogen using various biochemical, spectroscopic, and computational methods. NBT assay and carbonyl content revealed glyco-nitro-oxidation-mediated oxidative stress, which was effectively mitigated by TQ in a concentration-dependent manner. The secondary structural alterations in fibrinogen were prevented by TQ as observed by circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR). Moreover, multiple assays and electron microscopy confirmed structural perturbations leading to the development of fibrillar aggregates that were reduced in TQ treated samples. Our findings project TQ as a potent protective agent against hyperglycemia and related human complications.

Investigating the Role of Skin Autofluorescence in Gestational Diabetes Mellitus: A Systematic Review

Gestational diabetes mellitus (GDM) is a pregnancy-specific condition that can cause serious complications for both the mother and the fetus. Preventing these complications requires optimum glycemic control. Skin autofluorescence (SAF) is a non-invasive and innovative method that evaluates the levels of advanced glycation end products, markers of hyperglycemia, that could aid in the optimum management of GDM-complicated pregnancies. This systematic review aims to assess SAF's potential utility in the prediction of short-term and long-term outcomes in GDM. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, with the protocol identifier CRD42024559012, we used "(skin autofluorescence OR SAF) AND (gestational diabetes mellitus OR GDM)" as a search criterion on the PubMed, Scopus, and Web of Science databases. After a rigorous selection process, we included five articles, which evaluated SAF values and GDM, SAF and pregnancies complicated by diabetes mellitus, and SAF and macrosomia. GDM diagnosis varies due to the different approaches among the major guidelines, leading to variations in interpretation and diagnostic thresholds. Across studies, this variability contributes to inconsistent SAF values. As a standardized and objective marker, SAF could provide a uniform criterion, improving GDM management. Further research is needed to validate its clinical utility.

Design and synthesis of terephthalic dihydrazide analogues as dual inhibitors of glycation and urease

The overexpression of urease is the root cause of peptic ulcers and gastritis. Therefore, introducing new inhibitors against urease is a possible therapeutic approach to overcoming the pathogenesis; for instance, limiting the risk of development of urinary calculi. Moreover, glycation is the leading cause of several complications. Thus, in this study, we synthesized novel terephthalic dihydrazide analogues and evaluated their biological importance. These terephthalic dihydrazide analogues were characterized using advanced spectroscopic techniques, such as 1H NMR, 13C NMR, 19F NMR and HRMS (ESI+), and FT-IR. Fortunately, 6 of the 11 synthesized compounds exhibited urease inhibitory capability, and 8 compounds exhibited anti-glycation capability. Compounds 13-14, 20 and 23 showed significant urease inhibition with IC50 values of 63.12 ± 0.28, 65.71 ± 0.40, 49.2 ± 0.49 and 51.45 ± 0.39 μM, respectively. Meanwhile, they exhibited potent anti-glycation activity with IC50 values of 67.53 ± 0.46, 68.06 ± 0.43, 48.32 ± 0.42 and 54.36 ± 0.40 μM, respectively. Molecular docking of active urease inhibitors showed their good binding at the entrance of the active site and good correlation with our in vitro results.

Inhibition of the Parkinson's Disease-Related Protein DJ-1 by Endogenous Neurotoxins of the 1,2,3,4-Tetrahydroisoquinoline Family

The protein DJ-1 appears to play a protective role in the development of Parkinson's disease (PD). Here, we show that endogenous neurotoxins of the 1,2,3,4-tetrahydroisoquinoline family (TIQs), formed upon reaction of various aldehydes such as methylglyoxal (MGO) with the neurotransmitter dopamine, act as irreversible inhibitors of the esterase activity of human DJ-1, with IC50 values between 15 and 57 μM. The presence of a catechol function appears to be essential for these inhibitory effects, which may be at the origin of the oxidation of cysteine 106, a crucial residue in the DJ-1 active site, thereby leading to DJ-1 inhibition. We also show that these endogenous neurotoxins inhibit the protective effects of DJ-1 against glycated guanosine diphosphate (GDP) formation and against alpha-synuclein (aSyn) aggregation induced by MGO. In total, the observed inhibition of DJ-1 by these endogenous neurotoxins may contribute to their damaging effects on the nervous system and, should be taken into account in therapeutic strategies for PD and related disorders.

Screening of Methylglyoxal Fluctuations in the Kidneys of Diabetic Nephropathy Mice Using a Europium(III) Complex-Based Dual-Mode Luminescence Probe

The global surge in diabetes mellitus (DM) and its associated complications has prompted significant efforts to mitigate this growing public health challenge. Among these complications, diabetic nephropathy (DN) is of particular concern due to its high rates of morbidity and mortality. Extensive research has identified methylglyoxal (MGO) and MGO-derived advanced glycation end products (AGEs) as critical contributors to the pathogenesis of DN. Thus, there is a pressing need for precise and effective methodologies for monitoring MGO levels in complicated biological systems. Herein, we report the first Eu3+ complex-based dual-mode luminescence probe, DAPTTA-Eu3+, for accurate MGO detection using time-gated luminescence (TGL) and luminescence lifetime measurements. The probe initially exists in a "dark state" characterized by a relatively short luminescence lifetime. Upon interaction with MGO, intense Eu3+ emission is restored, accompanied by a significant increase in luminescence lifetime. These features enable DAPTTA-Eu3+ to serve as a reliable luminescence probe for accurate MGO quantification, utilizing TGL and the luminescence lifetime as complementary detection strategies. Moreover, the cell membrane-permeable derivative of the probe, AM-DAPTTA-Eu3+, was prepared and used for TGL imaging of both exogenous and endogenous MGO in live cells, which also allowed the MGO fluctuations in the kidneys of DN mice and the nephroprotective effects of metformin against DN to be assessed. Notably, by exploiting the differential expressions of renal MGO, the DN and cisplatin-induced acute kidney injury (AKI) were successfully distinguished. These results underscored the practicability of AM-DAPTTA-Eu3+ across varying kidney-related pathophysiological conditions, suggesting its high potential in clinical DN diagnosis.

Italian Biodiversity: A Source of Edible Plant Extracts with Protective Effects Against Advanced Glycation End Product-Related Diseases

Background: Italy's plant biodiversity, characterized by many plant species, is an important source of bioactive secondary metabolites that help reduce the risk of the development of advanced glycation end product (AGE)-related diseases. AGEs are involved in various diseases, such as diabetes, cardiovascular, and neurodegenerative disorders. Therefore, the aim of the study was to investigate the antiglycative, hypoglycemic, and neuroprotective properties of nine edible plant extracts using different in vitro assays. Methods: The ability of the extracts to counteract AGE formation was evaluated at different stages of the glycation reaction using in vitro systems based on the determination of Amadori products and the co-incubation of a model protein with a dicarbonyl compound under different experimental conditions. In addition, the extracts' methylglyoxal (MGO) and glyoxal (GO) trapping ability was investigated. Hypoglycemic activity was assessed by measuring α-amylase inhibition, while the neuroprotective effects were explored by testing amyloid β peptide 1-42 (Aβ1-42) fibrillogenesis inhibition. Results: All extracts generally had a dose-related capacity for the inhibition of AGE formation, mainly at the intermediate stage of the glycation reaction; high trapping capacity against MGO and GO; and promising hypoglycemic properties. In addition, they affected the fibrillogenesis process by reducing mature amyloid fibril formation and altering fibril morphology. Conclusions: All tested extracts had promising anti-fibrillogenic properties. Rosa canina extract was the most active among the tested plant species given its antiglycative activity (about 80% inhibition of AGE formation), trapping capacity against MGO and GO (almost 100%), hypoglycemic effects (66.20 ± 0.88%), and anti-fibrillogenic effects (69.00 ± 4.49% inhibition), indicating its suitability in the management of AGE-related diseases and for the potential development of a novel food ingredient.

Advanced glycation end products and breast cancer risk in a sample of the ORDET cohort

IntroductionBreast cancer is the most common cancer among women, and metabolic syndrome (MetS) is a risk factor for breast cancer, especially postmenopausal breast cancer. We evaluated the role of the advanced glycated end products (AGEs) levels contributing to the association between MetS and breast cancer risk.MethodsPlasma AGEs were measured in a case-control study nested within the Hormones and Diet in the Etiology of Breast Tumors (ORDET) cohort, including 40 incident postmenopausal breast cancer cases (20 with MetS and 20 without) and 40 postmenopausal controls (20 with MetS and 20 without). The association between AGEs and breast cancer was analyzed using Bayesian logistic regression models. An informative prior for the exposure coefficient, modeled as a normal distribution, centered on the natural logarithm of an odds ratio ((OR)=1.635) derived from prior evidence, was employed alongside weakly informative priors (WIPs). Bayesian linear regression with WIPs was used to examine the association between MetS and AGEs. Estimates were reported with SDs and 90% and 95% credible intervals (CI).ResultsAGEs were associated with higher breast cancer risk both with the informative prior (OR = 1.745, SD):0.362; 90% CI:1.218-2.390; 95% CI:1.137-2.548) and the WIP (OR = 1.861, SD = 0.661; 90% CI:1.026-3.082; 95% CI:0.924-3.528) specification. Although the difference in plasma AGEs in women with and without MetS was not significant, we found a suggestion of higher levels in women with MetS (mean difference in standardized AGEs between individuals with and without MetS = 0.155, SD = 0.245; 90% CI:-0.246 to 0.553; 95% CI:-0.322 to 0.625).ConclusionsThese data, although from a small sample of women, support a role of endogenous AGEs in the pathological pathways underlying the association between MetS and breast cancer development.

Quality control of corn silk extract using IR spectroscopy along with statistical methods

Aqueous extracts of corn silk exhibit glycation-inhibitory activity. Lignin is the active component of these extracts. As corn silk is highly nutritious and has medicinal value, it can be used as a functional food and cosmetics. However, to achieve this goal, it is necessary to evaluate its quality. As lignin, which could be used as a marker compound for quality control, is a macromolecule, HPLC cannot be employed for the quality control of the aqueous extracts of corn silk. We here develop a method to evaluate the anti-glycation activity of the aqueous extracts of corn silk using attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy along with multivariate statistical analysis. The inhibitory activity was evaluated using two multivariate calibrations: principal component regression (PCR) and partial least square regression (PLSR). The spectral areas of the PCR model were 633.5-880.3, 1191.8-1359.6, 1423.1-1492.6, and 2572.6-2974.7 cm-1. Its coefficient of correlation (R2 = 0.981) and root mean square error of cross validation (RMSECV = 2.356) were highly predictable. The spectral regions of 983.5-985.5 and 1021.1-1107.9 cm-1 offered the best prediction models for the PLSR model. The R2 value for the correlation between the actual values and the FTIR-predicted values was 0.994, while the corresponding RMSECV was 1.325%. Hence, FTIR spectroscopy along with multivariate calibration is a useful method for evaluating active corn silk aqueous extracts.

Emerging technologies in reducing dietary advanced glycation end products in ultra-processed foods: Formation, health risks, and innovative mitigation strategies

The widespread consumption of ultra-processed foods (UPFs) results from industrialization and globalization, with their elevated content of sugar, fat, salt, and additives, alongside the formation of dietary advanced glycation end products (AGEs), generating considerable health risks. These risks include an increased incidence of diabetes, cardiovascular diseases, and neurodegenerative disorders. This review explores the mechanisms of AGE formation in UPFs and evaluates emerging technologies and additives aimed at mitigating these risks. Both thermal methods (air frying, low-temperature vacuum heating, microwave heating, and infrared heating) and non-thermal techniques (high-pressure processing, pulsed electric fields, ultrasound, and cold plasma) are discussed for their potential in AGE reduction. Additionally, the review evaluates the efficacy of exogenous additives, including amino acids, polysaccharides, phenolic compounds, and nanomaterials, in inhibiting AGE formation, though results may vary depending on the specific additive and food matrix. The findings demonstrate the promise of these technologies and additives for reducing AGEs, potentially contributing to healthier food processing practices and the promotion of improved public health outcomes.

Accumulation of Nε-carboxymethyllysine and Nε-carboxyethyllysine in precooked pork during cold storage and subsequent reheating

This research aimed to investigate the levels of Nε-carboxymethyllysine (CML) and Nε-carboxyethyllysine (CEL) in precooked pork (100 °C, 10 min) as affected by storage (0 °C, 0-11 d) and subsequent reheating (100 °C, 5 min). A longer storage duration led to more CML (average increased: 69-128 %) and CEL (average increased: 11-44 %) in precooked pork, while the reheating resulted in average increases of 86 % CML and 32 % CEL compared to their initial levels in precooked pork. However, the storage duration did not significantly (p > 0.05) affect CML/CEL formation in precooked pork during the subsequent reheating. The levels of CML/CEL and glyoxal/methylglyoxal had no obvious relationship, but CML formation was linked to lipid oxidation in precooked or reheated pork. The accumulation of CML and CEL in precooked meat produced during the initial precooking, storage, and reheating implies the necessity to control their generation in these products.

Metabolites and Charcot Foot: A Comprehensive Analysis Through Mendelian Randomization

BACKGROUND

Multiple studies have shown metabolites may have potential effects on Charcot foot. However, the Mendelian randomization method has not yet explored the relationship between metabolites and Charcot foot.

METHODS

We selected genetic variants from the publicly available Genome-wide Association Studies (GWAS) summary database to represent 1400 metabolites described in recent research. Mendelian randomization (MR) analysis was carried out to examine the relationships between these metabolites and Charcot foot. Significant single nucleotide polymorphism (SNP) data associated with exposure were screened out through association analysis. Valid instrumental variables (IVs) were then selected, excluding SNPs with F-statistic values below 10. The MR analyses primarily employed the inverse variance weighted (IVW) method. Bayesian weighted Mendelian randomization (BWMR), constrained maximum likelihood(cML), contamination mixture(Conmix), robust adjusted profile score(RAPS), and debiased inverse-variance weighted(deIVW) method were used to enhance the results. Colocalization analysis was performed to identify shared causal genetic variants associated with the resulting phenotypes. Sensitivity analyses, including assessments of Cochrane's Q test, egger intercept, and MR PRESSO test were conducted to confirm the robustness of the results.

RESULTS

After preliminary MR exploration, the IVW results exhibited positive causal relationships between hexadecenedioate (C16:1-DC) levels (OR = 0.698, 95%CI: 0.586 to 0.831, PFDR = 0.040), octadecadienedioate (C18:2-DC) levels (OR = 0.665, 95%CI: 0.552 to 0.800, PFDR = 0.021), octadecanedioylcarnitine (C18-DC) levels (OR = 0.676, 95%CI: 0.553 to 0.827, PFDR = 0.067) and Charcot foot. Colocalization analysis indicated that the above three metabolites share a common causal variant at the same genomic location with Charcot foot. Sixty-four metabolites with suggestive causal relationships with Charcot foot were also identified, among which 25 kinds of metabolites were positively correlated with Charcot foot, and 33 metabolites were negatively associated with Charcot foot. The BWMR, cML, Conmix, RAPS, and deIVW results supported our preliminary MR results. In several results, sensitivity analyses showed heterogeneity and horizontal pleiotropy, while the causal relationships obtained through FDR correction did not show any significant heterogeneity and horizontal pleiotropy. No reverse causal association was detected.

CONCLUSION

We detected protective and risk metabolites in Charcot foot. Controlling metabolites may decrease Charcot foot risk and serve as a novel therapeutic biomarker for the therapy.

Alpha-Lipoic Acid Treatment Reduces the Levels of Advanced End Glycation Products in Type 2 Diabetes Patients with Neuropathy

Background/Objectives: Type 2 diabetes mellitus (T2DM) and its macro- and microvascular complications are major health concerns with multiple factors, like advanced end glycation products (AGEs), in the background. AGEs induce long-lasting functional modification of the proteins and collagen in the vascular wall and nerve tissue. We investigated the effect of alpha-lipoic acid (ALA) treatment on AGEs, soluble AGE receptor (sRAGE), the AGE/sRAGE ratio, and the parameters of endothelial dysfunction and their correlations. Methods: In our 6-month intervention study, 54 T2DM patients with neuropathy treated according to the actual therapeutic guidelines with unchanged oral antidiabetic drugs were included and treated by daily oral administration of 600 mg ALA. A total of 24 gender and age-matched T2DM patients without neuropathy served as controls. Results: In our work, we first demonstrated the attenuating effect of alpha lipoic acid therapy on AGEs in humans (11.89 (9.44-12.88) to 10.95 (9.81-12.82) AU/μg (p = 0.017)). sRAGE levels or the AGEs/sRAGE ratio were not affected by ALA treatment or by the presence of neuropathy. We found a correlation between the changes of AGEs and the improvement of current perception threshold and progranulin levels, and an inverse correlation with the change of asymmetric dimethylarginine. Conclusions: According to our results, ALA decreases AGEs, which may contribute to the clinically well-known beneficial effect in diabetic neuropathy and improvement of endothelial function.

Mechanism of action of Panax ginseng alcohol extract based on orexin-mediated autophagy in the treatment of sleep and cognition in aged sleep-deprived rats

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng (P. ginseng) C. A. Meyer. has been used extensively globally as a medicine. It has a therapeutic effect on sleep and is an attractive alternative for patients with insomnia. The United States Patent of Invention has approved the use of P. ginseng alcohol extract (GAE) in nutraceuticals or food to improve sleep. It has shown promise as an effective therapeutic agent for improving sleep and cognition. However, its mechanism of action is not yet fully understood.

AIM OF THE STUDY

To investigate the therapeutic benefits of GAE on sleep and cognition and its underlying mechanism in aged sleep-deprived rats, with a focus on orexin-mediated autophagy function.

MATERIALS AND METHODS

We conducted in vivo tests in an aged sleep-deprivation rat model produced using p-chlorophenylalanine (PCPA) coupled with modified multi-platform method to examine the therapeutic effects and mechanisms of GAE. A pentobarbital sodium-induced sleep test and water maze were used to assess sleep and cognitive performance, respectively. An enzyme-linked immunosorbent assay was used to determine orexin levels and aging and sleep markers in serum and hypothalamic tissues. Hematoxylin-eosin staining and Nissl staining were used to assess histopathological changes, and autophagy levels were assessed using transmission electron microscopy, immunofluorescence. Western blot and immunohistochemical staining were performed to detect the levels of orexin, orexin-receptor proteins, and autophagy-associated proteins to study the effects of GAE on hippocampal neurons, and the underlying mechanisms.

RESULTS

In aged sleep-deprived rats, GAE treatment prolonged sleep duration, improved cognitive function, prevented hippocampal neuronal damage, increased the number of Nissl bodies, improved aging and sleep markers, and enhanced the LC3A/B expression in autophagosomes and neurons. The amount of orexin in serum and hypothalamic tissue and OX1R, OX2R, and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) proteins also reduced, which resulted in the inhibition of the PI3K/Akt/mTOR pathway and activation of the autophagy process.

CONCLUSIONS

GAE may reduce hypothalamic orexin secretion and interact with orexin receptors to inhibit the PI3K/Akt/mTOR signalling network and activate autophagy. This may be a potential mechanism of action of GAE in regulating sleep-related cognitive function.

Generation of advanced glycation end products from glycated protein or fructose/glyoxal-protein adducts under in vitro simulated gastrointestinal digestion

Advanced glycation end products (AGEs) are a heterogeneous group of compounds formed both endogenously and exogenously through reactions between reducing sugars and amino acids within the proteins. The digestive tract may also serve as a site for endogenous AGEs generation. This study examined whether additional AGEs are formed during the digestion of glycated protein diets and meal-resembling systems (dietary proteins with fructose or glyoxal). The digestion of glycated protein showed that free AGEs were gradually released, but no additional AGEs were generated. In contrast, co-digestion of dietary proteins with fructose or glyoxal resulted in the formation of additional AGEs, and the reaction substrates (fructose or glyoxal) were depleted during digestion. Additionally, the lysine released from proteins decreased, leading to a loss of nutritional value of the food during co-digestion. The formation of AGEs and the depletion of essential amino acids in the gut may have significant implications for human health.

Reference Values of Skin Autofluorescence by Age Groups in Healthy Spanish Adults: Results from the EVasCu Study, a Systematic Review, and a Meta-Analysis

Background/Objectives: Age is a known predictor of skin autofluorescence (SAF) across populations, but age-based reference values are lacking for the Spanish population. This study aims to establish SAF reference values for healthy Spanish adults by age group, compare these with other populations, and estimate optimal SAF cut-off points by age range. Additionally, it aims to analyse the influence of sex, smoking, and skin phototype. Methods: This cross-sectional EVasCu study included 390 healthy subjects aged over 18 years. Participants' age, sex, smoking status, and skin were recorded and categorised into age groups. Advanced glycation end products were measured through the SAF. A systematic review and meta-analysis, including an EVasCu study, was performed to obtain pooled means and standard deviations by age group. Results: The mean SAF Spanish values by age were (95% CI): (i) 18-19 years: 1.34-1.56 arbitrary units (AU); (ii) 20-29 years: 1.56-1.70 AU; (iii) 30-39 years: 1.66-1.84 AU; (iv) 40-49 years: 1.79-1.91 AU; (v) 50-59 years: 2.07-2.21 AU; (vi) ≥60 years: 2.07-2.50 AU. SAF was significantly correlated with age (r = 0.531; p < 0.001), smoking status (r = -0.196; p < 0.001), and skin phototype (r = 0.138; p = 0.007), and SAF was greater in smokers and dark-skinned individuals (p < 0.05). No significant differences were found in the SAF values for sex. The results of the meta-analysis were in line with those of the present study, providing reference values of SAF for the general population. Conclusions: SAF increases linearly with age in healthy individuals, and higher levels of SAF are observed in smokers and dark-skinned individuals.

Effect of diabetes and hyperglycaemia on the physical and mechanical properties of dentine: a systematic review

OBJECTIVES

The aim of this systematic review was to assess the effect of DM (Type 1 and Type 2 Diabetes) and hyperglycaemia on the physical and mechanical properties of dentine which is critical for successful endodontic treatment.

METHOD

An electronic search of the following databases: PubMed, MEDLINE, Web of Science and the grey literature was performed up until July 2024. In vitro and in vivo studies on the effect of DM or hyperglycaemia on the mechanical and physical properties of dentine were included. Non-English language literature was excluded.

RESULTS

Of the 234 articles identified, 15 met the inclusion criteria. Four studies evaluated how artificially induced glycation or natural glycation of dentine due to aging affects the mechanical properties of dentine. Five studies investigated the influence of Type 2 Diabetes (T2D) on dentine's mechanical properties, while two studies focused on the effects of Type 1 Diabetes (T1D). A further, four studies compared the effects of both T1D and T2D on the dentine. The studies were heterogeneous and a range of mechanical and physical properties were evaluated.

CONCLUSION

DM and AGEs negatively influence the physical and mechanical properties of dentine however, there remains a paucity of evidence and further studies are needed.

CLINICAL SIGNIFICANCE

Diabetes Mellitus (DM) is a chronic metabolic disease characterised by hyperglycaemia, an altered immune response and complications associated with collagen connective tissues. DM can influence bone metabolism and alter its physical and mechanical properties via glycation processes within collagen and changes to osteoblast activities. While bone and dentine share similarities, dentine is unique as it is intimately associated with the dental pulp. Inflammation within the pulp can induce calcification and tertiary dentine deposition and so exploring the influence of DM on the mechanical properties of dentine is warranted to understand the clinical significance.

Eye on the horizon: The metabolic landscape of the RPE in aging and disease

To meet the prodigious bioenergetic demands of the photoreceptors, glucose and other nutrients must traverse the retinal pigment epithelium (RPE), a polarised monolayer of cells that lie at the interface between the outer retina and the choroid, the principal vascular layer of the eye. Recent investigations have revealed a metabolic ecosystem in the outer retina where the photoreceptors and RPE engage in a complex exchange of sugars, amino acids, and other metabolites. Perturbation of this delicate metabolic balance has been identified in the aging retina, as well as in age-related macular degeneration (AMD), the leading cause of blindness in the Western world. Also common in the aging and diseased retina are elevated levels of cytokines, oxidative stress, advanced glycation end-products, increased growth factor signalling, and biomechanical stress - all of which have been associated with metabolic dysregulation in non-retinal cell types and tissues. Herein, we outline the role of these factors in retinal homeostasis, aging, and disease. We discuss their effects on glucose, mitochondrial, lipid, and amino acid metabolism in tissues and cell types outside the retina, highlighting the signalling pathways through which they induce these changes. Lastly, we discuss promising avenues for future research investigating the roles of these pathological conditions on retinal metabolism, potentially offering novel therapeutic approaches to combat age-related retinal disease.

Repurposing Nano Curcumin: Unveiling its Therapeutic Potential in Diabetic Nephropathy

Currently, Diabetic Nephropathy (DN) stands as the predominant global cause of endstage renal disease. Many scientists believe that diabetes will eventually spread to pandemic levels due to the rising prevalence of the disease. While the primary factor leading to diabetic nephropathy is vascular dysfunction induced by hyperglycemia, several other pathological elements, such as fibrosis, inflammation, and oxidative stress, also contribute to the progression of the disease. The primary targets of current DN therapy approaches are the underlying abnormalities of hypertension and glucose. With several targets and fewer side effects, curcumin is a commonly utilized antioxidant in DN. The present study emphasizes the critical role of oxidative stress and inflammation in the development of diabetic nephropathy. It reveals how these factors induce damage in key kidney cell types, highlighting their potential as therapeutic targets for this disease. In addition, by concentrating on Nrf2, SIRT1, HMGB1, NF-κB, and NLRP3 of curcumin, has strong anti- inflammatory and antioxidant characteristics. This review describes the role of curcumin in the therapeutic application of diabetic nephropathy. In this attempt, we tried to elaborate on the bench-to-bedside aspects of curcumin in DN, including clinical and preclinical investigations. The rationales of curcumin's mechanisms in alleviating symptoms of the DN were discussed. Curcumin could serve as the potential therapeutic agent for the patient seeking to recover from DN.

Effects of advanced glycation end products on stem cell

In recent years, stem cell therapy has become a pivotal component of regenerative medicine. Stem cells, characterized by their self-renewal capacity and multidirectional differentiation potential, can be isolated from a variety of biological tissues, including adipose tissue, bone marrow, the umbilical cord, and the placenta. The classic applications of stem cells include human pluripotent stem cells (hPSCs) and mesenchymal stem cells (MSCs). However, numerous factors can influence the normal physiological function of stem cells. For instance, in diabetes mellitus, advanced glycation end products (AGEs) accumulate in the extracellular matrix (ECM), impairing the physiological function of stem cells. These substances are closely associated with aging and the progression of numerous degenerative diseases. AGEs can create an environment that is detrimental to the normal physiological functions of stem cells. By binding to the primary cellular receptor for advanced glycation end products (RAGE), AGEs disrupt the physiological activities of stem cells. The binding of RAGE to various ligands triggers the activation of downstream signaling pathways, contributing to the pathophysiological development of diabetes, aging, neurodegenerative diseases, and cancer. Therefore, there is an urgent need for comprehensive research on the impact of AGEs on stem cells, which could provide new insights into the therapeutic application of stem cells in regenerative medicine.

Role of urinary trace elements in diabetic kidney disease: a cross-sectional analysis

INTRODUCTION

The balance of trace elements plays an important role in diabetic kidney disease (DKD) patients. However, studies on the differences in urinary trace elements across different DKD stages are scarce. This study aimed to explore the associations between nine essential trace elements and DKD.

RESEARCH DESIGN AND METHODS

This cross-sectional analysis included 830 diabetic patients. Participants were classified into non-DKD (NDKD) and DKD, the latter was further grouped into mid and end DKD based on estimated glomerular filtration rate (eGFR), and the case and control were matched based on age and sex. The concentration of urinary trace elements was measured with inductively coupled plasma mass spectrometry.

RESULTS

Urinary concentrations of copper (Cu) and manganese (Mn) in DKD patients were significantly higher than that of NDKD patients, whereas that of iron (Fe), cobalt, selenium, and nickel (Ni) of DKD were lower. Positive correlations between urinary Mn/Cu and the risk of mid-stage and end-stage DKD were revealed by conditional logistic regression, while Fe and Ni were negatively associated with the risk of DKD. In mixed effect analyses, no significant trend was found for joint trace element exposure and risk of mid DKD, while negative associations between combined effects of trace elements and the risk of end DKD were observed.

CONCLUSIONS

This study revealed different associations between trace elements and the risk of mid and end DKD using both single and mixture effect modeling. The results suggested that the urinary trace element profile might be associated with the progression of DKD, which provides important insights for understanding the pathogenesis of DKD and developing individualized nutritive management strategies.

New Insights into the Role of SGLT-2 Inhibitors in the Prevention of Dementia

Diabetes mellitus (DM) is a chronic disease associated with numerous complications, including cardiovascular diseases, nephropathy, and neuropathy. Sodium-glucose cotransporter 2 (SGLT-2) inhibitors, a class of novel antidiabetic agents, have demonstrated promising therapeutic effects beyond glycemic control, with potential benefits extending to the cardiovascular and renal systems. Recently, research has increasingly focused on exploring the potential role of SGLT-2 inhibitors in preventing dementia. The aim of this review is to summarize the current research suggesting that SGLT-2 inhibitors, such as empagliflozin and dapagliflozin, may have neuroprotective effects that reduce dementia risk and improve cognitive function in type 2 diabetes patients. These benefits are likely due to better glycemic control, reduced oxidative stress, and less advanced glycation end-product (AGE) formation, all linked to neurodegeneration. Despite these promising findings, existing studies are limited by small sample sizes and short follow-up durations, which may not adequately capture long-term outcomes. To establish more robust evidence, larger-scale, long-term randomized controlled trials (RCTs) involving diverse populations are needed. These studies should involve diverse populations and focus on understanding the mechanisms behind the neuroprotective effects. Addressing these limitations will provide clearer guidelines for using SGLT-2 inhibitors in dementia prevention and management. This will help improve therapeutic strategies for cognitive health in diabetic patients.

Two new flavonoids from the leaves of Garcinia smeathmannii, in vitro and in silico anti-inflammatory potentials

Garcinia smeathmannii is a well-known plant for its uses in the effective treatment of intestinal parasites, skin eruptions and skin burns. The dichloromethane-methanol (2:3) crude extract of the leaves of G. smeathmannii led to the isolation and characterization of twenty compounds (1-20) using chromatographic and spectroscopic techniques. Extracts and compounds were screened in vitro for their anti-inflammatory (ROS), antiglycation and antileishmanial (L. tropica) activities. Compounds were also screened for their in silico anti-inflammatory activities using Maestro 4.2.1 software with the co-crystal complex structures of the ovine oCOX-1: meloxicam (PDB Id: 4O1Z) and murine mCOX-2: meloxicam (PDB Id: 4M11) proteins. An unprecedented flavonol (1) and a flavone dimer (2) together with eighteen known compounds (3-20) were characterized. All the tested samples in vitro revealed no antiglycation and antileishmanial activities. Beside, extracts revealed moderate anti-inflammatory activities (IC50 ranging from 24.1 ± 2.0 to 34.7 ± 0.8 μg/mL). Only compound (13) revealed an anti-inflammatory activity which was 9.33 times more active than the reference (Ibuprofen, IC50 = 11.2 ± 1.9 μg/mL) with IC50 of 1.2 ± 0.0 μg/mL. Compounds (2-9, 11-13 and 19-20) were docked and the docking scores were ranging from -10.178 to -6.119 (kcal/mol) which were in agreement with the experimental anti-inflammatory activity. These results are in agreement with the traditional uses of the leave of G. smeathmannii as cataplasm for skin eruption and as analgesic agent.

Pre-diagnostic plasma advanced glycation end-products and soluble receptor for advanced glycation end-products and mortality in colorectal cancer patients

Advanced glycation end-products (AGEs), formed endogenously or obtained exogenously from diet, may contribute to chronic inflammation, intracellular signaling alterations, and pathogenesis of several chronic diseases including colorectal cancer (CRC). However, the role of AGEs in CRC survival is less known. The associations of pre-diagnostic circulating AGEs and their soluble receptor (sRAGE) with CRC-specific and overall mortality were estimated using multivariable-adjusted Cox proportional hazards regression among 1369 CRC cases in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Concentrations of major plasma AGEs, Nε-[carboxy-methyl]lysine (CML), Nε-[carboxy-ethyl]lysine (CEL) and Nδ-[5-hydro-5-methyl-4-imidazolon-2-yl]-ornithine (MG-H1), were measured using ultra-performance liquid chromatography mass-spectrometry. sRAGE was assessed by enzyme-linked immunosorbent assay. Over a mean follow-up period of 96 months, 693 deaths occurred of which 541 were due to CRC. Individual and combined AGEs were not statistically significantly associated with CRC-specific or overall mortality. However, there was a possible interaction by sex for CEL (Pinteraction = .05). Participants with higher sRAGE had a higher risk of dying from CRC (HRQ5vs.Q1 = 1.67, 95% CI: 1.21-2.30, Ptrend = .02) or any cause (HRQ5vs.Q1 = 1.38, 95% CI: 1.05-1.83, Ptrend = .09). These associations tended to be stronger among cases with diabetes (Pinteraction = .03) and pre-diabetes (Pinteraction <.01) before CRC diagnosis. Pre-diagnostic AGEs were not associated with CRC-specific and overall mortality in individuals with CRC. However, a positive association was observed for sRAGE. Our findings may stimulate further research on the role of AGEs and sRAGE in survival among cancer patients with special emphasis on potential effect modifications by sex and diabetes.

Binding interaction of sodium benzoate, potassium sorbate and sodium dihydrogen citrate with BSA as food preservatives: in Vitro analysis and computational studies

Advanced glycation end products (AGEs) are obtained intermediate from nonenzymatic reactions between reducing sugars and proteins, lipids, or nucleic acids and it's associated with diabetic complications. Today, potassium sorbate (PS), sodium citrate (CIT) and sodium benzoate (SB) were widespread used as food preservatives that can easily enter biological matrices. Here, the interaction between glycosylation Bovine Serum Albumin (BSA) and food preservatives individually and combination of two and three was studied by biochemical and simulation analysis. The results revealed that an increase in absorption and fluorescent intensity in all treated groups. The most carbonyl and glycosylated compounds were observed in the treatment with PS and its combined groups with two preservatives. Treatment with three preservatives alone or combination caused a significant increase in red blood cell hemolysis and MDA level (p < 0.05). The results of the in vitro experiments were in line with the docking studies and the interaction of the compounds with albumin was observed in important subdomain of BSA that show the stability of the BSA-ligand complex. Simultaneous treatment and the combination of two or three food preservatives cause their synergistic effect in possible harm to the body. In addition, the molecular docking experiment suggests that Sodium Benzoate, Potassium Sorbate and Sodium Dihydrogen Citrate can interact with BSA.

Cinnamaldehyde ameliorates diabetes-induced biochemical impairments and AGEs macromolecules in a pre-clinical model of diabetic nephropathy

PURPOSE

Cinnamaldehyde, has various therapeutic potentials including glucose-lowering effect, and insulinotropic effect; however, its glycation inhibitory mechanism is not known yet. In this study, we explored the effects of cinnamaldehyde for its AGEs inhibitory mechanism in a streptozotocin-complete Freund's adjuvant (STZ-CFA) induced diabetic nephropathy (DN) rat model.

METHODS

Pre-clinical DN model was developed by the administration of multiple low doses of STZ-CFA in rats, mainly characterized by abnormal blood parameters and nephrotic damages. Diabetes-related systemic profile and histopathological hallmarks were evaluated using biochemical assays, microscopic imaging, immunoblot, and real-time PCR analyses, supported by cinnamaldehyde-albumin interaction assessed using STD-NMR and in silico site-directed interactions in the presence of glucose.

RESULTS

Cinnamaldehyde-treatment significantly reversed DN hallmarks, fasting blood glucose (FBG), serum insulin, glycated hemoglobin (HbA1c), urinary microalbumin, and creatinine contrasted to non-treated DN rats and aminoguanidine, a positive reference advanced glycation end products (AGEs) inhibitor. The pathological depositions of AGEs, receptor for advanced glycation end products (RAGE), and carboxymethyl lysine (CML), and transcriptional levels of AGE-RAGE targeted immunomodulatory factors (IL1β, TNF-α, NF-κB, TGF-β) were significantly improved in cinnamaldehyde treated rats as compared to aminoguanidine. Cinnamaldehyde post-treatment improved pancreatic pathology and systemic glycemic index (0.539 ± 0.01 vs. 0.040 ± 0.001, P < 0.001) in DN rats. Subsequently, in silico profiling of cinnamaldehyde defined the competitive binding inhibition with glucose in AGE and RAGE receptors that was further confirmed by in vitro STD-NMR analysis.

CONCLUSION

These findings suggest potential role of cinnamaldehyde in reversing STZ-induced diabetic nephropathic impairments; therefore, appears promising candidate for further pharmacological explorations towards diabetes-associated complications.

Nanomedicine regulating PSC-mediated intercellular crosstalk: Mechanisms and therapeutic strategies

Pancreatic fibrosis (PF) is primarily distinguished by the stimulation of pancreatic stellate cells (PSCs) and excessive extracellular matrix deposition, which is the main barrier impeding drug delivery and distribution. Recently, nanomedicine, with efficient, targeted, and controllable drug release characteristics, has demonstrated enormous advantages in the regression of pancreas fibrotic diseases. Notably, paracrine signals from parenchymal and immune cells such as pancreatic acinar cells, islet cells, pancreatic cancer cells, and immune cells can directly or indirectly modulate PSC differentiation and activation. The intercellular crosstalk between PSCs and these cells has been a critical event involved in fibrogenesis. However, the connections between PSCs and other pancreatic cells during the progression of diseases have yet to be discussed. Herein, we summarize intercellular crosstalk in the activation of PSCs and its contribution to the development of common pancreatic diseases, including pancreatitis, pancreatic cancer, and diabetes. Then, we also examine the latest treatment strategies of nanomedicine and potential targets for PSCs crosstalk in fibrosis, thereby offering innovative insights for the design of antifibrotic nanomedicine. Ultimately, the enhanced understanding of PF will facilitate the development of more precise intervention strategies and foster individually tailored therapeutic approaches for pancreatic diseases.

"NO" controversy?: A controversial role in insulin signaling of diabetic encephalopathy

Insulin, a critical hormone in the human body, exerts its effects by binding to insulin receptors and regulating various cellular processes. While nitric oxide (NO) plays an important role in insulin secretion and acts as a mediator in the signal transduction pathway between upstream molecules and downstream effectors, holds a significant position in the downstream signal network of insulin. Researches have shown that the insulin-NO system exhibits a dual regulatory effect within the central nervous system, which is crucial in the regulation of diabetic encephalopathy (DE). Understanding this system holds immense practical importance in comprehending the targets of existing drugs and the development of potential therapeutic interventions. This review extensively examines the characterization of insulin, NO, Nitric oxide synthase (NOS), specific NO pathway, their interconnections, and the mechanisms underlying their regulatory effects in DE, providing a reference for new therapeutic targets of DE.

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.

Exploring diabesity pathophysiology through proteomic analysis using Caenorhabditis elegans

Introduction

Diabesity, characterized by obesity-driven Type 2 diabetes mellitus (T2DM), arises from intricate genetic and environmental interplays that induce various metabolic disorders. The systemic lipid and glucose homeostasis is controlled by an intricate cross-talk of internal glucose/insulin and fatty acid molecules to maintain a steady state of internal environment.

Methods

In this study, Caenorhabditis elegans were maintained to achieve glucose concentrations resembling the hyperglycemic conditions in diabetic patients to delve into the mechanistic foundations of diabesity. Various assays were conducted to measure intracellular triglyceride levels, lifespan, pharyngeal pumping rate, oxidative stress indicators, locomotor behavior, and dopamine signaling. Proteomic analysis was also performed to identify differentially regulated proteins and dysregulated KEGG pathways, and microscopy and immunofluorescence staining were employed to assess collagen production and anatomical integrity.

Results

Worms raised on diets high in glucose and cholesterol exhibited notably increased intracellular triglyceride levels, a decrease in both mean and maximum lifespan, and reduced pharyngeal pumping. The diabesity condition induced oxidative stress, evident from heightened ROS levels and distinct FT-IR spectroscopy patterns revealing lipid and protein alterations. Furthermore, impaired dopamine signaling and diminished locomotors behavior in diabesity-afflicted worms correlated with reduced motility. Through proteomic analysis, differentially regulated proteins encompassing dysregulated KEGG pathways included insulin signaling, Alzheimer's disease, and nicotinic acetylcholine receptor signaling pathways were observed. Moreover, diabesity led to decreased collagen production, resulting in anatomical disruptions validated through microscopy and immunofluorescence staining.

Discussion

This underscores the impact of diabesity on cellular components and structural integrity in C. elegans, providing insights into diabesity-associated mechanisms.

The Role of Advanced Glycation End Products in Saphenous Vein Graft Failure

OBJECTIVE

We aimed to investigate the relationship between advanced glycation end product (AGE) levels in patients with saphenous vein graft (SVG) failure and in patients without SVG failure.

SUBJECTS AND METHODS

In our study, 55 patients with a history of previous coronary artery bypass grafting (CABG) surgery, who subsequently underwent coronary angiography for any reason and were found to have either SVG occlusion or significant lesions, were included as study patients. Additionally, 55 patients who have had CABG surgery without SVG failure for at least 1 year served as the control group. AGE values of the patients were measured using the skin autofluorescence method.

RESULTS

In our study results, we observed a significant difference in AGE levels between the two groups of patients with similar demographic characteristics (SVG failure groups AGE 3.2 [2.8-3.6] vs. control groups AGE 2.4 [2.1-2.7] p < 0.001). In the receiver operating characteristic curve analysis, we determined the ability of AGE levels to detect SVG failure with an area under the curve of 0.869. We found that in patients with AGE >3, it could detect SVG failure with a sensitivity of 70.9% and a specificity of 87.3%.

CONCLUSIONS

Our results demonstrate that AGE levels can predict SVG failure risk inexpensively, easily, and quickly.

OBJECTIVE

We aimed to investigate the relationship between advanced glycation end product (AGE) levels in patients with saphenous vein graft (SVG) failure and in patients without SVG failure.

SUBJECTS AND METHODS

In our study, 55 patients with a history of previous coronary artery bypass grafting (CABG) surgery, who subsequently underwent coronary angiography for any reason and were found to have either SVG occlusion or significant lesions, were included as study patients. Additionally, 55 patients who have had CABG surgery without SVG failure for at least 1 year served as the control group. AGE values of the patients were measured using the skin autofluorescence method.

RESULTS

In our study results, we observed a significant difference in AGE levels between the two groups of patients with similar demographic characteristics (SVG failure groups AGE 3.2 [2.8-3.6] vs. control groups AGE 2.4 [2.1-2.7] p < 0.001). In the receiver operating characteristic curve analysis, we determined the ability of AGE levels to detect SVG failure with an area under the curve of 0.869. We found that in patients with AGE >3, it could detect SVG failure with a sensitivity of 70.9% and a specificity of 87.3%.

CONCLUSIONS

Our results demonstrate that AGE levels can predict SVG failure risk inexpensively, easily, and quickly.

State-of-the-Art in Skin Fluorescent Photography for Cosmetic and Skincare Research: From Molecular Spectra to AI Image Analysis

Autofluorescence is a remarkable property of human skin. It can be excited by UV and observed in the dark using special detection systems. The method of fluorescence photography (FP) is an effective non-invasive tool for skin assessment. It involves image capturing by a camera the emission of light quanta from fluorophore molecules in the skin. It serves as a useful tool for cosmetic and skincare research, especially for the detection of pathological skin states, like acne, psoriasis, etc. To the best of our knowledge, there is currently no comprehensive review that fully describes the application and physical principles of FP over the past five years. The current review covers various aspects of the skin FP method from its biophysical basis and the main fluorescent molecules of the skin to its potential applications and the principles of FP recording and analysis. We pay particular attention to recently reported works on the automatic analysis of FP based on artificial intelligence (AI). Thus, we argue that FP is a rapidly evolving technology with a wide range of potential applications. We propose potential directions of the development of this method, including new AI algorithms for the analysis and expanding the range of applications.

Structural basis for FN3K-mediated protein deglycation

Protein glycation is a universal, non-enzymatic modification that occurs when a sugar covalently attaches to a primary amine. These spontaneous modifications may have deleterious or regulatory effects on protein function, and their removal is mediated by the conserved metabolic kinase fructosamine-3-kinase (FN3K). Despite its crucial role in protein repair, we currently have a poor understanding of how FN3K engages or phosphorylates its substrates. By integrating structural biology and biochemistry, we elucidated the catalytic mechanism for FN3K-mediated protein deglycation. Our work identifies key amino acids required for binding and phosphorylating glycated substrates and reveals the molecular basis of an evolutionarily conserved protein repair pathway. Additional structural-functional studies revealed unique structural features of human FN3K as well as differences in the dimerization behavior and regulation of FN3K family members. Our findings improve our understanding of the structure of FN3K and its catalytic mechanism, which opens new avenues for therapeutically targeting FN3K.

Role of advanced glycation end-products in age-associated kidney dysfunction in naturally aging mice

AIMS

Advanced glycation end-products (AGEs) are implicated in the age-related decline of renal function, exacerbated by conditions, such as hyperglycemia and oxidative stress. The accumulation of AGEs in the kidneys contributes to the progressive decline in renal function observed with aging. However, the precise role and mechanisms of AGEs in the age-related decline of renal function remain unclear. In this study, we investigated the impact and potential mechanisms of AGEs on aging kidneys in naturally aging mice.

MATERIALS AND METHODS

Male C57BL/6 mice were divided into three groups: 6-, 57-, and 107-week-old. First, the 6- and 107-week-old mice were euthanized. The remaining mice were divided into young (6 weeks) and old (57 weeks) groups. The 57-week-old mice were orally administered aminoguanidine (100 mg/kg/day), an AGEs inhibitor, or vehicle for 13 weeks, resulting in a final age of 70 weeks. The serum and kidney tissues were collected for biochemical measurement, histological examination, immunohistochemistry staining, and immunoblotting analysis.

KEY FINDINGS

Our findings revealed a notable accumulation of AGEs in both serum and kidney tissue specimens and renal dysfunction in naturally aging mice. Aminoguanidine not only reversed AGEs accumulation but also ameliorated renal dysfunction. Additionally, aminoguanidine attenuated the upregulation of fibrosis markers (phosphorylated p38/α-SMA and C/EBP homologous protein, CHOP), senescence markers (p53 and p21), and oxidative stress marker (4-HNE) in the aging kidneys.

SIGNIFICANCE

These findings underscore the critical role of AGEs in age-related renal dysfunction and highlight the therapeutic potential of aminoguanidine in mitigating fibrosis and senescence, offering prospective avenues for combating age-associated renal ailments.

Periodontal tissue susceptibility to glycaemic control in type 2 diabetes

AIM

To assess the direct effect of intensive glycaemic control on periodontal tissues in patients with diabetes mellitus.

MATERIALS AND METHODS

Twenty-nine patients with type 2 diabetes were enrolled and hospitalized to receive a 2-week intensive glycaemic control regimen. We observed and analysed the systemic and oral disease indicators before and after treatment and clarified the indicators related to periodontal inflammation.

RESULTS

A significant reduction in glycaemic and periodontal parameters, including glycated albumin levels and periodontal inflamed surface area (PISA), was observed after treatment. The changes in PISA per tooth, indicative of periodontal healing, exhibited a bimodal distribution; the patients were divided into two groups on this basis. Correlations were observed between the changes in PISA per tooth and fasting plasma glucose, acetoacetic acid, and beta-hydroxybutyrate levels in the PISA-improved group. Significantly lower levels of C-peptide, coefficient of variation of R-R interval, and ankle-brachial pressure index were observed before treatment in the PISA non-improved group.

CONCLUSIONS

Glycaemic control treatment can effectively improve periodontitis in patients with type 2 diabetes, even in the absence of specific periodontal treatments. However, the periodontal responsiveness to glycaemic control treatment depends on the systemic condition of the patient.

Oridonin Attenuates Diabetes‑induced Renal Fibrosis via the Inhibition of TXNIP/NLRP3 and NF‑κB Pathways by Activating PPARγ in Rats

INTRODUCTION

Oridonin possesses remarkable anti-inflammatory, immunoregulatory properties. However, the renoprotective effects of oridonin and the underlying molecular mechanisms in diabetic nephropathy (DN). We hypothesized that oridonin could ameliorate diabetes‑induced renal fibrosis.

METHODS

Streptozocin (STZ)-induced diabetic rats were provided with a high-fat diet to establish a type 2 diabetes mellitus (T2DM) animal model, and then treated with Oridonin (10, 20 mg/kg/day) for two weeks. Kidney function and renal fibrosis were assessed. High glucose-induced human renal proximal tubule epithelial cells (HK-2) were also treated with oridonin. The expression of inflammatory factors and fibrotic markers were analyzed.

RESULTS

Oridonin treatment preserved kidney function and markedly limited the renal fibrosis size in diabetic rats. The renal fibrotic markers were inhibited in the oridonin 10 mg/kg/day and 20 mg/kg/day groups compared to the T2DM group. The expression of thioredoxin-interacting proteins/ nod-like receptor protein-3 (TXNIP/NLRP3) and nuclear factor (NF)‑κB pathway decreased, while that of peroxisome proliferator-activated receptor-gamma (PPARγ) increased in the oridonin treatment group compared to the non-treated group. In vitro, PPARγ intervention could significantly regulate the effect of oridonin on the high glucose-induced inflammatory changes in HK-2 cells.

CONCLUSION

Oridonin reduces renal fibrosis and preserves kidney function via the inhibition of TXNIP/NLRP3 and NF‑κB pathways by activating PPARγ in rat T2DM model, which indicates potential effect of oridonin in the treatment of DN.

Mesenchymal Stem Cells Regulate Microglial Polarization via Inhibition of the HMGB1/TLR4 Signaling Pathway in Diabetic Retinopathy

Diabetic retinopathy (DR) is recognized as the most prevalent retinal degenerative disorder. Inflammatory response usually precedes microvascular alteration and is the primary factor of diabetic retinopathy. Activated microglia express many pro-inflammatory cytokines that exacerbate retina inflammation and disruption. In the present study, we found that MSCs alleviated blood-retina barrier (BRB) breakdown in diabetic rats, as evidenced by reduced retinal edema, decreased vascular leakage, and increased occludin expression. The MSC-treated retinal microglia exhibited reduced expression of M1-phenotype markers in the diabetic rats, including inducible nitric oxide synthase (iNOS), CD16, and pro-inflammatory cytokines. On the other hand, MSCs increased the expression of M2-phenotype markers, such as arginase-1 (Arg-1), CD206, and anti-inflammatory cytokines. HMGB1/TLR4 signaling pathway is activated in DR and inhibited after MSC treatment. Consistent with in vivo evidence, MSCs drove BV2 microglia toward M2 phenotype in vitro. Overexpression of HMGB1 in microglia reversed the effects of MSC treatment, suggesting HMGB1/TLR4 pathway is necessary for MSCs' regulatory effects on microglia polarization. Collectively, MSCs exert beneficial effects on DR by polarizing microglia from M1 toward M2 phenotype via inhibiting the HMGB1/TLR4 signaling pathway.

Overview of pyroptosis mechanism and in-depth analysis of cardiomyocyte pyroptosis mediated by NF-κB pathway in heart failure

The pyroptosis of cardiomyocytes has become an essential topic in heart failure research. The abnormal accumulation of these biological factors, including angiotensin II, advanced glycation end products, and various growth factors (such as connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta, among others), activates the nuclear factor-κB (NF-κB) signaling pathway in cardiovascular diseases, ultimately leading to pyroptosis of cardiomyocytes. Therefore, exploring the underlying molecular biological mechanisms is essential for developing novel drugs and therapeutic strategies. However, our current understanding of the precise regulatory mechanism of this complex signaling pathway in cardiomyocyte pyroptosis is still limited. Given this, this study reviews the milestone discoveries in the field of pyroptosis research since 1986, analyzes in detail the similarities, differences, and interactions between pyroptosis and other cell death modes (such as apoptosis, necroptosis, autophagy, and ferroptosis), and explores the deep connection between pyroptosis and heart failure. At the same time, it depicts in detail the complete pathway of the activation, transmission, and eventual cardiomyocyte pyroptosis of the NF-κB signaling pathway in the process of heart failure. In addition, the study also systematically summarizes various therapeutic approaches that can inhibit NF-κB to reduce cardiomyocyte pyroptosis, including drugs, natural compounds, small molecule inhibitors, gene editing, and other cutting-edge technologies, aiming to provide solid scientific support and new research perspectives for the prevention and treatment of heart failure.