Thermal treatment under oxidative conditions increases the antioxidant and antiglycation activity of Chilean Tórtola beans (Phaseolus vulgaris).

The influence of oxygen on the thermal treatment (TT) of secondary metabolite-enriched extracts (SMEEs) from Tórtola beans and procyanidin C1 (PC1) on the inhibition of advanced glycation end products (AGEs) generation in proteins was investigated. SMEE was incubated at 4 °C (control) or thermally treated at 60 °C for 2 h, at either 0 % O2 (I) or 20 % O2 (II). Treatments I and II increased the content of procyanidin dimers B2. Treatment II was more effective than the control or treatment I in preventing homocysteine oxidation and AGEs generation. TT of PC1 at 0 % or 20 % O2 generated procyanidin dimers and tetramers. PC1 TT at 20 % O2 exhibited higher oxidation potentials and lower IC50 values of fluorescent AGEs than those of controls or TT at 0 % O2. These findings indicate that SMEE from Tórtola beans after treatment II changes the degree of polymerization and oxidation procyanidins, thereby increasing their antiglycation activity.

Enhanced anti-inflammatory effect of fish myofibrillar protein by introducing pectin oligosaccharide and its molecular mechanisms.

This study investigated the efficacy of glycation with edible uronic acid-containing oligosaccharides via the Maillard reaction to enhance the anti-inflammatory effect of fish myofibrillar protein (Mf). Lyophilized Mf was reacted with pectin oligosaccharide (PO, half of the total protein weight) at 60 °C and 35 % relative humidity for up to 12 h to produce glycated Mf (Mf-PO). After pepsin and trypsin digestion, the anti-inflammatory effect was assessed by measuring the secretions of proinflammatory cytokines in LPS-stimulated RAW 264.7 macrophages, and the anti-inflammatory effect of Mf was enhanced by PO-glycation without marked lysine loss and browning. The effects on the expressions of genes related to the LPS-stimulated signaling pathway in macrophages were also examined. PO-glycation suppressed LPS-stimulated inflammation by suppressing expression of cd14 and enhancing suppressive effect of Mf on the TLR4-MyD88-dependent inflammatory signaling pathway. Therefore, as an edible reducing sugar, PO could be an effective bioindustrial material for developing anti-inflammatory Mf.

Syzygium cumini (L.) skeels mitigate diabetic nephropathy by regulating Nrf2 pathway and mitocyhondrial dysfunction: In vitro and in vivo studies.

ETHNOPHARMACOLOGICAL PREVALENCE: Hyperglycemia in diabetes increases the generation of advanced glycation end products (AGEs) through non-enzymatic reactions. The interaction between AGEs and their receptors (RAGE) leads to oxidative and inflammatory stress, which plays a pivotal role in developing diabetic nephropathy. Syzygium cumini (SC) L. (DC.) homeopathic preparations viz. 200C, 30C, and mother tincture [MT] are used to treat diabetes. This study aimed to elucidate the regulatory effects of SC preparations (200C, 30C, and MT) on the nuclear factor erythroid 2-related factor 2 (Nrf2) - nuclear factor-κB (NF-κB) pathways and mitochondrial dysfunction in mitigating diabetic nephropathy (DN). MATERIALS AND METHODS: Streptozotocin-induced diabetic rats were treated with SC preparations (200C, 30C, MT; 1:20 dilution in distilled water; 600 µL/kg body weight) and metformin (45 mg/kg body weight) twice daily for 40 days. DN was evaluated through biochemical parameters and histological examination. Renal tissue lysates were analyzed for glycation markers. Protein and gene levels of Nrf2, NF-κB, and mitochondrial dysfunctional signaling were determined via western blotting and RT-qPCR. An immunohistochemical analysis of the kidneys was performed. In vitro, human serum albumin (HSA - 10 mg/ml) was glycated with methylglyoxal (MGO - 55 mM) in the presence of SC preparations (200C, 30C, MT) for eight days. Glycated samples (400 µg/mL) were incubated with renal cells (HEK-293) for 24 h. Further reactive oxygen species production, Nrf2 nuclear translocation, and protein or gene expression of Nrf2 and apoptosis markers were analyzed by western blotting, RT-qPCR, and flow cytometry. Molecular docking of gallic and ellagic acid with the HSA-MGO complex was performed. RESULT: In vivo experiments using streptozotocin-induced diabetic rats treated with SC preparations exhibited improved biochemical parameters, preserved kidney function, and reduced glycation adduct formation in a dose-dependent manner. Furthermore, SC preparations downregulated inflammatory mediators such as RAGE, NF-κB, vascular endothelial growth factor (VEGF), and Tumor necrosis factor α (TNF-α) while upregulating the Nrf2-dependent antioxidant and detoxification pathways. They downregulated B-cell lymphoma 2 (Bcl-2) associated X-protein (BAX), C/EBP homologous protein (CHOP), Dynamin-related protein 1 (DRP1), and upregulated BCL 2 gene expression. Notably, SC preparations facilitated nuclear translocation of Nrf2, leading to the upregulation of antioxidant enzymes and the downregulation of oxidative stress markers. Molecular docking studies revealed favorable interactions between gallic (-5.26 kcal/mol) and ellagic acid (-4.71 kcal/mol) with the HSA-MGO complex. CONCLUSION: SC preparations mitigate renal cell apoptosis and mitochondrial dysfunction through Nrf2-dependent mechanisms.

Minimal mathematical model for glycation of albumin.

BACKGROUND: Glycated albumin (GA) is often described as a reflection of glucose exposure over the past 2-4 weeks. We examined the scale of the operative interval for changes in %GA from the perspective of a theoretical model for GA formation, by simulating the time course of changes in %GA after changes in glucose. METHODS: Probability of survival of albumin (A) was according to first-order elimination based on t1/2 of 17 days. Probability of formation of GA from A per unit time was proportional to glucose (G) and a glycation rate constant, k, deduced from reference values for %GA vs. G. We then simulated the kinetics of changes in %GA for conditions in which a prior steady-state (constant G) was followed by a step change in G. RESULTS: The glycation rate constant k was 9.79e-4/d/(mmol/L). We simulated changes in %GA for two scenarios involving step changes in G at time = 0: A. from 10 mmol/L to 15 mmol/L (%GA ultimately moves from 19.3% to 26.4%); B. from 15 mmol/L to 10 mmol/L (%GA ultimately moves from 26.4% to 19.3%). For both scenarios, the fractional transition of %GA between respective starting points and ultimate endpoints was after 30 days approximately 80% of the ultimate full transition. CONCLUSIONS: Model-based calculations support the description of %GA as a reflection of G over the past 4-6 weeks, longer than the period of 2-4 weeks that is commonly cited.

Efficient purification of soluble receptor for advanced glycation end-products from Sus scrofa lung tissue and synthesis of its binding ligand, glycated bovine serum albumin.

A receptor for advanced glycation end products (RAGE) has emerged as a crucial player in various pathological conditions due to its involvement in inflammation and cellular dysfunction. Its soluble isoform, sRAGE, has garnered significant attention for its competitive inhibitory effects and potential therapeutic applications. However, obtaining sRAGE with appropriate glycosylation patterns for binding to glycated proteins has been challenging, often requiring costly expression systems. Here, we present a novel approach for producing and purifying sRAGE from Sus scrofa lungs, bypassing the need for expensive expression systems. Previous protocols for sRAGE extraction faced reproducibility issues due to high viscosity and haemoglobin content of the solution. To address this, we developed a method for selective haemoglobin precipitation using a zinc-containing buffer, enabling purification via various chromatographic methods. Through a combination of chromatographic techniques, we obtained sRAGE in suitable purity, identified using HPLC-MS/MS. Additionally, producing glycated proteins for RAGE receptor activation often involved lengthy protocols or inadequate separation from reactants. Thus, we devised a rapid method for producing and purifying pure BSA glycated with ribose, addressing a critical gap in the field. Functional studies, conducted using Native PAGE, demonstrated the capability of purified proteins to bind to each other.

Increased Levels of Circulating Methylglyoxal Have No Consequence for Cerebral Microvascular Integrity and Cognitive Function in Young Healthy Mice.

Diabetes and other age-related diseases are associated with an increased risk of cognitive impairment, but the underlying mechanisms remain poorly understood. Methylglyoxal (MGO), a by-product of glycolysis and a major precursor in the formation of advanced glycation end-products (AGEs), is increased in individuals with diabetes and other age-related diseases and is associated with microvascular dysfunction. We now investigated whether increased levels of circulating MGO can lead to cerebral microvascular dysfunction, blood-brain barrier (BBB) dysfunction, and cognitive impairment. Mice were supplemented or not with 50 mM MGO in drinking water for 13 weeks. Plasma and cortical MGO and MGO-derived AGEs were measured with UPLC-MS/MS. Peripheral and cerebral microvascular integrity and inflammation were investigated. Cerebral blood flow and neurovascular coupling were investigated with laser speckle contrast imaging, and cognitive tests were performed. We found a 2-fold increase in plasma MGO and an increase in MGO-derived AGEs in plasma and cortex. Increased plasma MGO did not lead to cerebral microvascular dysfunction, inflammation, or cognitive decline. This study shows that increased concentrations of plasma MGO are not associated with cerebral microvascular dysfunction and cognitive impairment in healthy mice. Future research should focus on the role of endogenously formed MGO in cognitive impairment.

Associations of Advanced Glycation End Products with Sleep Disorders in Chinese Adults.

BACKGROUND: Advanced glycation end products (AGEs), a group of food processing byproducts, have been implicated in the development of various diseases. However, the relationship between circulating AGEs and sleep disorders remains uncertain. METHODS: This cross-sectional study elucidated the association of plasma AGEs with sleep disorders among 1732 Chinese adults who participated in the initial visit (2019-2020) of the Tongji-Shenzhen Cohort (TJSZC). Sleep behavior was assessed using self-reported questionnaires and precise accelerometers. Plasma levels of AGEs, including Nε-(Carboxymethyl)lysine (CML), Nε-(Carboxyethyl)lysine (CEL), and Nδ-(5-hydro-5-methyl-4-imidazolone-2-yl)-ornithine (MG-H1), were quantified by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). RESULTS: In logistic regression, per IQR increment in individual AGEs was associated with an increased odds ratio of short sleep duration (CML: 1.11 [1.00, 1.23]; CEL: 1.16, [1.04, 1.30]), poor sleep quality (CML: 1.33 [1.10, 1.60]; CEL: 1.53, [1.17, 2.00]; MG-H1: 1.61 [1.25, 2.07]), excessive daytime sleepiness (CML: 1.33 [1.11, 1.60]; MG-H1: 1.39 [1.09, 1.77]), and insomnia (CML: 1.29 [1.05, 1.59]). Furthermore, in weighted quantile sum regression and Bayesian kernel machine regression analyses, elevated overall exposure levels of plasma AGEs were associated with an increased risk of sleep disorders, including short sleep duration, poor sleep quality, excessive daytime sleepiness, and insomnia, with CML being identified as the leading contributor. Insufficient vegetable intake and higher dietary fat intake was associated with an increase in plasma CEL. CONCLUSIONS: These findings support a significant association between plasma AGEs and sleep disorders, indicating that AGEs may adversely influence sleep health and reducing the intake of AGEs may facilitate preventing and ameliorating sleep disorders.

Inhibitory Effects of Aqueous Ethanol Extracts of Poplar-Type Propolis on Advanced Glycation End Products and Protein Oxidation.

(1) Background: The non-enzymatic glycation of proteins is a significant contributor to the formation of advanced glycation end products (AGEs) and intermediates that are responsible for diabetic complications. It is imperative to explore effective inhibitors to prevent protein glycation. (2) Methods: This study aimed to investigate the inhibitory potential of various aqueous ethanol extracts of poplar-type propolis on AGEs and oxidative modifications in bovine serum albumin (BSA)-glucose and BSA-methylglyoxal models. (3) Results: The results revealed that these propolis extracts exhibited significant effectiveness in inhibiting the formation of total AGEs, pentosidine, and Nε-carboxymethyllysine (CML). Furthermore, the investigation discovered that these propolis extracts can effectively inhibit oxidative modification, based on measuring the levels of carbonyl and thiol groups and analyzing tryptophan fluorescence quenching. Notably, 75% ethanol extracts of propolis (EEP) exhibited the highest inhibitory activity, surpassing the chemical inhibitor aminoguanidine (AG). (4) Conclusions: The remarkable anti-glycation potency of aqueous ethanol extracts of poplar-type propolis can be attributed to their elevated contents of phenolic compounds, especially abundant flavonoids, which inhibit the formation of AGEs by scavenging free radicals, decreasing the levels of reactive oxygen species (ROS), and capturing reactive carbonyl species (RCS) in the protein glycation process. Our results indicate that poplar-type propolis may be a potential AGE inhibitor and could be used to develop functional foods and nutraceuticals to prevent diabetic complications.

Effect of Extraction Methods on Chemical Characteristics and Bioactivity of Chrysanthemum morifolium cv. Fubaiju Extracts.

Chrysanthemum morifolium cv. Fubaiju (CMF) is regarded as one of the three most renowned varieties of white Chrysanthemum in China, and different extraction methods have significant effects on its composition and activities. Therefore, six extractions were used in this study to assess the effects on extracts. The basic chemical composition showed that hot water extract (Hw) had the highest total phenolic content, alkali water immersion-assisted hot water extract (Al) had the highest content of protein, and enzyme-assisted hot water extract (Enz) had the highest content of carbohydrate. The UPLC-Q-Exactive-MS results evinced the presence of 19 small-molecule compounds, including chlorogenic acid, caffeic acid, tuberonic acid glucoside, luteolin-7-O-rutinoside, and other substances. In addition, the antioxidant test found that the Hw exhibited the best 1,1-diphenyl-2-picrylhydrazyl (DPPH) (82.05 ± 1.59 mM TE/mg) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (61.91 ± 0.27 mM TE/mg) scavenging ability. The anti-glycation test demonstrated that Enz possessed the most pronounced inhibitory effect on glycation products, including fructosamine and advanced glycation end products (AGEs). Additionally, the Enz also exhibited the most significant inhibitory effect on the protein oxidation product N'-formylkynurenine. The correlation analysis revealed that there was a close relationship between antioxidant properties and glycation resistance of extracts, and tuberonic acid glucoside, 1,3-di-O-caffeoylquinic acid, 1,4-Dicaffeoylquinic acid, quercetin-7-O-ß-D-glucopyranoside, and isochlorogenic acid B were key small molecule components that affected activities. In summary, the extracts of CMF can be regarded as an excellent antioxidant and anti-glycosylation agent.

Crosstalk of Hyperglycaemia and Cellular Mechanisms in the Pathogenesis of Diabetic Kidney Disease.

Among all nephropathies, diabetic kidney disease (DKD) is the most common cause of kidney impairment advancement to end-stage renal disease (ESRD). Although DKD has no cure, the disease is commonly managed by strict control of blood glucose and blood pressure, and in most of these cases, kidney function often deteriorates, resulting in dialysis, kidney replacement therapy, and high mortality. The difficulties in finding a cure for DKD are mainly due to a poor understanding of the underpinning complex cellular mechanisms that could be identified as druggable targets for the treatment of this disease. The review is thus aimed at giving insight into the interconnection between chronic hyperglycaemia and cellular mechanistic perturbations of nephropathy in diabetes. A comprehensive literature review of observational studies on DKD published within the past ten years, with 57 percent published within the past three years was carried out. The article search focused on original research studies and reviews published in English. The articles were explored using Google Scholar, Medline, Web of Science, and PubMed databases based on keywords, titles, and abstracts related to the topic. This article provides a detailed relationship between hyperglycaemia, oxidative stress, and various cellular mechanisms that underlie the onset and progression of the disease. Moreover, it also shows how these mechanisms affect organelle dysfunction, resulting in fibrosis and podocyte impairment. The advances in understanding the complexity of DKD mechanisms discussed in this review will expedite opportunities to develop new interventions for treating the disease.

Elucidating the Antiglycation Effect of Creatine on Methylglyoxal-Induced Carbonyl Stress In Vitro.

Advanced glycation end products (AGEs) with multiple structures are formed at the sites where carbonyl groups of reducing sugars bind to free amino groups of proteins through the Maillard reaction. In recent years, it has been highlighted that the accumulation of AGEs, which are generated when carbonyl compounds produced in the process of sugar metabolism react with proteins, is involved in various diseases. Creatine is a biocomponent that is homeostatically present throughout the body and is known to react nonenzymatically with α-dicarbonyl compounds. This study evaluated the antiglycation potential of creatine against methylglyoxal (MGO), a glucose metabolite that induces carbonyl stress with formation of AGEs in vitro. Further, to elucidate the mechanism of the cytoprotective action of creatine, its effect on the accumulation of carbonyl proteins in the cells and the MGO-induced cellular damage were investigated using neuroblastoma cells. The results revealed that creatine significantly inhibits protein carbonylation by directly reacting with MGO, and creatine added to the culture medium suppressed MGO-derived carbonylation of intracellular proteins and exerted a protective effect on MGO-induced cytotoxicity. These findings suggest that endogenous and supplemented creatine may contribute to the attenuation of carbonyl stress in vivo.

Generation of affinity maps for thiazolidinediones with human serum albumin using affinity microcolumns. II. Effects of advanced glycation end products on multisite drug binding.

Multisite protein interactions by the thiazolidinedione-class drugs pioglitazone and rosiglitazone were examined by using high-performance affinity microcolumns that contained normal human serum albumin (HSA) vs HSA that had been modified to form advanced glycation end products by glyoxal (Go) or methylglyoxal (MGo). The results were used to generate an affinity map for these drugs at several key regions on HSA. Strong binding (∼105 M-1) by these drugs was seen at both Sudlow sites I and II. About a 50 % decrease in the affinities at Sudlow site II was observed for pioglitazone for Go-modified HSA, while either a 47 % decrease or 1.6-fold increase in affinity was seen for MGo-modified HSA, depending on the extent of modification. The binding affinity for rosiglitazone at Sudlow site II had a 40-83 % decrease for Go-modified HSA and either a non-significant change or 1.4-fold increase for MGo-modified HSA. At Sudlow site I, pioglitazone gave a 41 % decrease in affinity for either Go or MGo-modified HSA, and for rosiglitazone up to a 55 % decrease or 1.3-fold increase in affinity was noted. Positive allosteric effects were seen by these drugs with the tamoxifen site of HSA, and neither drug had any notable binding at the digitoxin site for the normal or modified forms of HSA. Rosiglitazone also had weak interactions at a site in subdomain IB, which increased in affinity by up to 5.0-fold with the Go- or MGo-modified HSA. This study illustrated how affinity microcolumns can be used to provide a detailed analysis of solute-protein systems that involve complex interactions. The data obtained should also be valuable in providing a better understanding of how drug interactions with HSA and other proteins can be altered by modifications of these binding agents in diseases such as diabetes.

Lens capsule advanced glycation end products induce senescence in epithelial cells: Implications for secondary cataracts.

Posterior capsule opacification (PCO) is a common complication after cataract surgery. Residual lens epithelial cells (LECs) on the anterior lens capsule, after cataract surgery, migrate to the posterior lens capsule and undergo transdifferentiation into myofibroblast-like cells. Those cells synthesize excessive amounts of extracellular matrix and contribute to fibrosis during PCO. Cellular senescence, a phenomenon that increases with aging, has been implicated in several fibrotic diseases. Here, we have investigated the prevalence of senescent LECs within the lens posterior capsule and the ability of advanced glycation end products (AGEs) in lens capsules to induce senescence, contributing to PCO. Aged lens capsules from pseudophakic human cadaver eyes showed the presence of senescent LECs. In human capsular bags, LECs showed an age-dependent increase in senescence after 28 days of culture. Human LECs cultured on aged lens capsules for 3 days underwent senescence; this effect was not seen in LECs cultured on young lens capsules. Human LECs cultured on an AGE-modified extracellular matrix (ECM-AGEs) showed an AGE-concentration-dependent increase in the expression of senescence markers and reactive oxygen species (ROS) levels. Treatment with a RAGE antagonist and ROS inhibitor reduced the expression of senescence and fibrotic markers. Additionally, conditioned media from ECM-AGEs-treated cells induced the expression of fibrotic markers in naïve LECs. Together, these suggest that AGEs in the capsule induce senescence of LECs, which triggers the mesenchymal transition of neighboring non-senescent LECs and contributes to PCO.

Importance of the Hemoglobin Glycation Index for Risk of Cardiovascular and Microvascular Complications and Mortality in Individuals with Type 2 Diabetes.

BACKGRUOUND: This study investigated the prognostic importance of the hemoglobin glycation index (HGI) for macrovascular and microvascular outcomes, mortality, and hypoglycemia occurrence in a type 2 diabetes cohort and compared it to glycated hemoglobin (HbA1c). METHODS: Baseline and mean first-year HGI and HbA1c, and the variability thereof, were assessed in 687 individuals with type 2 diabetes (median follow-up, 10.6 years). Multivariable Cox regression was conducted to evaluate the associations of HGI and HbA1c parameters with macrovascular (total and major cardiovascular events) and microvascular outcomes (microalbuminuria, advanced renal failure, retinopathy, and peripheral neuropathy), mortality (all-cause and cardiovascular), and moderate/severe hypoglycemia occurrence. RESULTS: During follow-up, there were 215 total cardiovascular events (176 major) and 269 all-cause deaths (131 cardiovascular). Microalbuminuria developed in 126 patients, renal failure in 104, retinopathy in 161, and neuropathy in 177. There were 90 hypoglycemia episodes. Both HGI and HbA1c predicted all adverse outcomes, except microalbuminuria and hypoglycemia. Their adjusted risks were roughly equivalent for all outcomes. For example, the adjusted hazard ratios (HRs) with 95% confidence intervals (CIs), estimated for 1 standard deviation increments, of mean first-year HGI were 1.23 (1.05 to 1.44), 1.20 (1.03 to 1.38), 1.36 (1.11 to 1.67), 1.28 (1.09 to 1.67), and 1.29 (1.09 to 1.54), respectively, for cardiovascular events, all-cause mortality, renal failure, retinopathy, and neuropathy; whereas the respective HRs (95% CIs) of mean HbA1c were 1.31 (1.12 to 1.53), 1.28 (1.11 to 1.48), 1.36 (1.11 to 1.67), 1.33 (1.14 to 1.55), and 1.29 (1.09 to 1.53). CONCLUSION: HGI was no better than HbA1c as a predictor of adverse outcomes in individuals with type 2 diabetes, and its clinical use cannot be currently advised.

Serum Soluble Receptors for Advanced Glycation End-Products May Predict Mortality in Microscopic Polyangiitis and Granulomatosis with Polyangiitis.

PURPOSE: This study aimed to investigate whether the serum extracellular newly identified receptor for advanced glycation end products binding protein (EN-RAGE) and the soluble form of RAGE (sRAGE) measured at diagnosis are associated with all-cause mortality in patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA). MATERIALS AND METHODS: Serum EN-RAGE and sRAGE were measured in 75 immunosuppressive drug-naïve MPA and GPA patients using an immunoassay, with their clinical and laboratory data reviewed. The optimal cut-off point of EN-RAGE and sRAGE was calculated by finding the threshold with the maximum sum of sensitivity and specificity. In addition, the least absolute shrinkage and selection operator regression was adopted to select variables included in the multivariable Cox proportional hazards (PH) regression model. RESULTS: The median age of the patients was 67.0 years, and 34% were male. Neither serum EN-RAGE nor sRAGE at diagnosis was correlated with the Birmingham Vasculitis Activity Score. Furthermore, no correlation was observed between serum EN-RAGE and sRAGE. Deceased patients had significantly lower serum EN-RAGE and higher serum sRAGE at diagnosis compared to surviving patients. Patients with serum EN-RAGE at diagnosis ≤84.37 ng/mL and serum sRAGE at diagnosis ≥1.82 ng/mL showed significantly lower survival probabilities compared to those without. In multivariable Cox PH regression model, only serum sRAGE at diagnosis ≥1.82 ng/mL, rather than serum EN-RAGE at diagnosis ≤84.37 ng/mL, was independently associated with all-cause mortality (hazard ratio 7.094). CONCLUSION: This study is the first to demonstrate that serum sRAGE at diagnosis may independently predict all-cause mortality during follow-up in patients with MPA and GPA.

On the role of the glycosylation of type I collagen in bone.

Glycan-protein interactions play a crucial role in biology, providing additional functions capable of inducing biochemical and cellular responses. In the extracellular matrix of bone, this type of interactions is ubiquitous. During the synthesis of the collagen molecule, glycans are post-translationally added to specific lysine residues through an enzymatically catalysed hydroxylation and subsequent glycosylation. During and after fibril assembly, proteoglycans are essential for maintaining tissue structure, porosity, and integrity. Glycosaminoglycans (GAGs), the carbohydrate chains attached to interstitial proteoglycans, are known to be involved in mineralization. They can attract and retain water, which is critical for the mechanical properties of bone. In addition, like other long-lived proteins, collagen is susceptible to glycation. Prolonged exposure of the amine group to glucose eventually leads to the formation of advanced glycation end-products (AGEs). Changes in the degree of glycosylation and glycation have been identified in bone pathologies such as osteogenesis imperfecta and diabetes and appear to be associated with a reduction in bone quality. However, how these changes affect mineralization is not well understood. Based on the literature review, we hypothesize that the covalently attached carbohydrates may have a water-attracting function similar to that of GAGs, but at different lengths and timescales in the bone formation process. Glycosylation potentially increases the hydration around the collagen triple helix, leading to increased mineralization (hypermineralization) after water has been replaced by mineral. Meanwhile, glycation leads to the formation of crosslinking AGEs, which are associated with a decrease in hydration levels, reducing the mechanical properties of bone.

The predictive capacity of biomarkers for clinical pulmonary oedema in patients with severe falciparum malaria is low: a prospective observational study.

BACKGROUND: Pulmonary oedema is a feared and difficult to predict complication of severe malaria that can emerge after start of antimalarial treatment. Proinflammatory mediators are thought to play a central role in its pathogenesis. METHODS: An exploratory study was conducted to evaluate the predictive capacity of biomarkers for development of clinical pulmonary oedema in patients with severe falciparum malaria at two hospitals in Bangladesh. Plasma concentrations of interleukin-6 (IL-6), IL-8, tumour necrosis factor (TNF), soluble Receptor of Advanced Glycation End-products (sRAGE), surfactant protein-D (SP-D), club cell secretory protein (CC16), and Krebs von den Lungen-6 (KL-6) on admission were compared with healthy controls. Correlations between these biomarker and plasma lactate and Plasmodium falciparum histidine-rich protein 2 (PfHRP2) levels were evaluated. Receiver Operating Characteristic (ROC) curves were constructed to assess the predictive capacity for clinical pulmonary oedema of the biomarkers of interest. RESULTS: Of 106 screened patients with falciparum malaria, 56 were classified as having severe malaria with a mortality rate of 29%. Nine (16%) patients developed clinical pulmonary oedema after admission. Plasma levels of the biomarkers of interest were higher in patients compared to healthy controls. IL-6, IL-8, TNF, sRAGE, and CC16 levels correlated well with plasma PfHRP2 levels (rs = 0.39; P = 0.004, rs = 0.43; P = 0.001, rs = 0.54; P < 0.001, rs = 0.44; P < 0.001, rs = 0.43; P = 0.001, respectively). Furthermore, IL-6 and IL-8 levels correlated well with plasma lactate levels (rs = 0.37; P = 0.005, rs = 0.47; P < 0.001, respectively). None of the biomarkers of interest had predictive capacity for development of clinical pulmonary oedema. CONCLUSIONS: IL-6, IL-8, TNF, sRAGE, SP-D, CC16 and KL-6 cannot be used in predicting clinical pulmonary oedema in severe malaria patients.

Dietary advanced glycation end-products (dAGEs) are not associated with the risk of cancer incidence. A systematic review and meta-analysis of prospective cohort studies.

A growing body of evidence indicates the association of dietary advanced glycation end-products (dAGEs) with the risk of cancer. This systematic review and meta-analysis aimed to assess the overall association between dAGEs and cancer incidence. An extensive search was carried out through online databases including PubMed, Scopus, and Web of Science up to June 2024. All reported HRs and their 95% CIs for risk of cancer were used to estimate log HRs and their standard errors (SEs). The overall risk estimate was obtained using a random effects model. Inter-study heterogeneity was determined using Cochrane's Q test and I-squared. Five prospective cohort studies with a total of 1,220,096 participants and 23,229 incident cancer cases (2193 pancreatic cancers, 11,443 breast cancers, 6162 colorectal cancers, and 3431 total cancers) were included in this meta-analysis. Compared with the lowest category of dAGEs, the pooled hazard ratio (HR) for overall cancers was 1.04 (95% CI: 0.94, 1.15; I 2 = 67.9%) for the highest category of dAGEs. Pooled estimates for different types of cancer showed no significant relationship between dAGEs and risk of breast cancer (HR: 1.119; 95% CI: 0.868, 1.444; I 2 = 77.6%; N = 2 studies), pancreatic cancer (HR: 1.242; 95% CI: 0.971, 1.588; I 2 = 0.0%; N = 2 studies), colon cancer (HR: 10.985; 95% CI: 0.887, 1.094; I 2 = 0.0%; N = 2 studies) and rectal cancer (HR: 0.940; 95% CI: 0.616, 1.433; I 2 = 57.7%; N = 2 studies). Dietary AGEs had no significant link with cancer risk. More well-designed prospective studies are required.

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.

Association between the soluble receptor for advanced glycation end products and diabetes mellitus: systematic review and meta-analysis.

BACKGROUND AND AIMS: In both type 1 diabetes (T1DM) and type 2 diabetes (T2DM), previous studies have yielded inconsistent findings regarding whether the levels of the soluble receptor for advanced glycation end products (sRAGE) are significantly altered. This meta-analysis aims to systematically evaluate the changes of sRAGE levels in patients with T1DM and T2DM. METHODS: PubMed, Embase, and Web of Science were systematically searched from inception until April 2024. We included studies reporting sRAGE levels in individuals with T1DM or T2DM, using non-diabetic healthy individuals as the control group. A random-effects model was applied to conduct a meta-analysis of effect measures (means and SDs). RESULTS: 49 datasets from 32 studies, involving 4948 subjects, met the inclusion criteria. A random-effects model meta-analysis showed that sRAGE levels in T1DM subjects (SMD 0.45, CI: 0.16-0.73, P = 0.002) and T2DM subjects with complications (SMD 1.59, CI: 0.77-2.41, P = 0.0001) were significantly higher than those in the control groups. No statistically significant change in sRAGE levels was observed in T2DM subjects without complications (SMD 0.01, CI: -0.61-0.64, P = 0.97). A decrease in sRAGE levels was observed in subjects with newly diagnosed T2DM (SMD-0.40, CI: -0.71- -0.09, P = 0.01). CONCLUSION: This meta-analysis indicated that sRAGE levels increased in T1DM patients and T2DM patients with complications, while they decreased in newly diagnosed T2DM patients. No significant difference was observed in T2DM patients without complications. Clearly, changes in sRAGE levels in patients with T1DM or T2DM are not uniform, but depend on the different types and stages of the disease. PROSPERO REGISTRATION NUMBER: CRD42024521252.