Comprehensive analysis of advanced glycation end-products in commonly consumed foods:presenting a database for dietary AGEs and associated exposure assessment

Advanced glycation end-products(AGEs)are a group of heterogeneous compounds formed in heatprocessed foods and are proven to be detrimental to human health.Currently,there is no comprehensive database for AGEs in foods that covers the entire range of food categories,which limits the accurate risk assessment of dietary AGEs in human diseases.In this study,we first established an isotope dilution UHPLCQq Q-MS/MS-based method for simultaneous quantification of 10 major AGEs in foods.The contents of these AGEs were detected in 334 foods covering all main groups consumed in Western and Chinese populations.Nε-Carboxymethyllysine,methylglyoxal-derived hydroimidazolone isomers,and glyoxal-derived hydroimidazolone-1 are predominant AGEs found in most foodstuffs.Total amounts of AGEs were high in processed nuts,bakery products,and certain types of cereals and meats(>150 mg/kg),while low in dairy products,vegetables,fruits,and beverages(<40 mg/kg).Assessment of estimated daily intake implied that the contribution of food groups to daily AGE intake varied a lot under different eating patterns,and selection of high-AGE foods leads to up to a 2.7-fold higher intake of AGEs through daily meals.The presented AGE database allows accurate assessment of dietary exposure to these glycotoxins to explore their physiological impacts on human health.

Receptor for advanced glycation end-products axis and coronavirus disease 2019 in inflammatory bowel diseases:A dangerous liaison?

Compelling evidence supports the crucial role of the receptor for advanced glycation end-products(RAGE)axis activation in many clinical entities.Since the beginning of the coronavirus disease 2019 pandemic,there is an increasing concern about the risk and handling of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection in inflammatory gastrointestinal disorders,such as inflammatory bowel diseases(IBD).However,clinical data raised during pandemic suggests that IBD patients do not have an increased risk of contracting SARS-CoV-2 infection or develop a more severe course of infection.In the present review,we intend to highlight how two potentially important contributors to the inflammatory response to SARS-CoV-2 infection in IBD patients,the RAGE axis activation as well as the cross-talk with the renin-angiotensin system,are dampened by the high expression of soluble forms of both RAGE and the angiotensin-converting enzyme(ACE)2.The soluble form of RAGE functions as a decoy for its ligands,and soluble ACE2 seems to be an additionally attenuating contributor to RAGE axis activation,particularly by avoiding the transactivation of the RAGE axis that can be produced by the virus-mediated imbalance of the ACE/angiotensin II/angiotensin II receptor type 1 pathway.

Dietary advanced glycation end-products aggravate non-alcoholic fatty liver disease

AIM To determine if manipulation of dietary advanced glycation end product(AGE), intake affects nonalcoholic fatty liver disease(NAFLD) progression and whether these effects are mediated via RAGE. METHODS Male C57Bl6 mice were fed a high fat, high fructose, high cholesterol(HFHC) diet for 33 wk and compared with animals on normal chow. A third group were given a HFHC diet that was high in AGEs. Another group was given a HFHC diet that was marinated in vinegar to prevent the formation of AGEs. In a second experiment, RAGE KO animals were fed a HFHC diet or a high AGE HFHC diet and compared with wildtype controls. Hepatic biochemistry, histology, picrosirius red morphometry and hepatic mR NA were determined. RESULTS Long-term consumption of the HFHC diet generated significant steatohepatitis and fibrosis after 33 wk. In this model, hepatic 4-hydroxynonenal content(a marker of chronic oxidative stress), hepatocyte ballooning, picrosirius red staining, α-smooth muscle actin and collagen type 1A gene expression were all significantly increased. Increasing the AGE content of the HFHC diet by baking further increased these markers of liver damage, but this was abrogated by pre-marination in acetic acid. In response to the HFHC diet, RAGE-/-animals developed NASH of similar severity to RAGE+/+ animals but were protected from the additional harmful effects of the high AGE containing diet. Studies in isolated Kupffer cells showed that AGEs increase cell proliferation and oxidative stress, providing a likely mechanism through which these compounds contribute to liver injury. CONCLUSION In the HFHC model of NAFLD, manipulation of dietary AGEs modulates liver injury, inflammation, and liver fibrosis via a RAGE dependent pathway. This suggests that pharmacological and dietary strategies targeting the AGE/RAGE pathway could slow the progression of NAFLD.

Increased expression of receptor for advanced glycation end-products worsens focal brain ischemia in diabetic rats

A rat model of diabetes mellitus was induced by a high fat diet, followed by focal brain ischemia induced using the thread method after 0.5 month. Immunohistochemistry showed that expression of receptor for advanced glycation end-products was higher in the ischemic cortex of diabetic rats compared with non-diabetic rats with brain ischemia. Western blot assay revealed increased phosphorylated c-Jun N-terminal kinase expression, and unchanged phosphorylated extracellular signal-regulated protein kinase protein expression in the ischemic cortex of diabetic rats compared with non-diabetic rats with brain ischemia. Additionally, phosphorylated p38 mitogen-activated protein kinase protein was not detected in any rats in the two groups. Severity of limb hemiplegia was worse in diabetic rats with brain ischemia compared with ischemia alone rats. The results suggest that increased expression of receptor for advanced glycation end-products can further activate the c-Jun N-terminal kinase pathway in mitogen-activated protein kinase, thereby worsening brain injury associated with focal brain ischemia in diabetic rats.

Fluorescent advanced glycation end-products (ages) detected by spectro-photofluorimetry, as a screening tool to detect diabetic microvascular complications

BACKGROUND: Advanced glycation end-products (AGEs) are one of the mechanisms related to diabetic vascular complications. However, since AGEs are multiple and heterogeneous moieties, there is no universally accepted method to measure them for clinical purposes. The aim of this work was to study the utility of a simple fluorimetric assay as predictor of complications. METHODS: Blood samples from 102 type 2 diabetic patients were obtained to assess glucose, glycosylated haemoglobin, creatinine, lipoproteins and C Reactive Protein (CRP), fluorescent AGES by spectrophotofluorimetry and non-fluorescent AGEs by measurement of N(ε)-carboxymethyl-Lysine (CML) using an ELISA kit in a subsample of 82 patients. Urinary fluorescent AGEs, albumin and creatinine were also measured in a morning urine sample. Microvascular complications were studied by ophthalmologic examination, albuminuria and peripheral nerve conduction velocity. RESULTS: Patients without microvascular complications had significantly lower levels of both serum and urinary AGEs. CML was associated with retinopathy. Multiple regression analysis confirmed that AGEs, length of diabetes and glycosylated haemoglobin were all variables associated with diabetic complications, in this sample. CONCLUSIONS: A simple fluorimetric assay to measure low molecular weight fluorescent AGEs, and CML could be employed as screening tools to predict diabetic complications, at a primary care setting. AGEs should probably be considered as another therapeutic target in diabetes management.

Receptor of advanced glycation end-products axis and gallbladder cancer:A forgotten connection that we should reconsider

Compelling evidence derived from clinical and experimental research has demonstrated the crucial contribution of chronic inflammation in the development of neoplasms,including gallbladder cancer.In this regard,data derived from clinical and experimental studies have demonstrated that the receptor of advanced glycation end-products(RAGE)/AGEs axis plays an important role in the onset of a crucial and long-lasting inflammatory milieu,thus supporting tumor growth and development.AGEs are formed in biological systems or foods,and food-derived AGEs,also known as dietary AGEs are known to contribute to the systemic pool of AGEs.Once they bind to RAGE,the activation of multiple and crucial signaling pathways are triggered,thus favoring the secretion of several proinflammatory cytokines also involved in the promotion of gallbladder cancer invasion and migration.In the present review,we aimed to highlight the relevance of the association between high dietary AGEs intakes and high risk for gallbladder cancer,and emerging data supporting that dietary intervention to reduce gallbladder cancer risk is a very attractive approach that deserves much more research efforts.

Advanced-glycation end-products axis:A contributor to the risk of severe illness from COVID-19 in diabetes patients

Compelling pieces of evidence derived from both clinical and experimental research has demonstrated the crucial role of the receptor for advanced-glycation end-products(RAGE)in orchestrating a plethora of proinflammatory cellular responses leading to many of the complications and end-organ damages reported in patients with diabetes mellitus(DM).During the coronavirus disease 2019(COVID-19)pandemic,many clinical reports have pointed out that DM increases the risk of COVID-19 complications,hospitalization requirements,as well as the overall severe acute respiratory syndrome coronavirus 2 case-fatality rate.In the present review,we intend to focus on how the basal activation state of the RAGE axis in common preexisting conditions in DM patients such as endothelial dysfunction and hyperglycemia-related prothrombotic phenotype,as well as the contribution of RAGE signaling in lung inflammation,may then lead to the increased mortality risk of COVID-19 in these patients.Additionally,the crosstalk between the RAGE axis with either another severe acute respiratory syndrome coronavirus 2 receptor molecule different of angiotensin-converting enzyme 2 or the renin-angiotensin system imbalance produced by viral infection,as well as the role of this multi-ligand receptor on the obesity-associated lowgrade inflammation in the higher risk for severe illness reported in diabetes patients with COVID-19,are also discussed.

Advanced glycation end-products change placental barrier function and tight junction in rats with gestational diabetes mellitus via the receptor for advanced glycation end products/nuclear factor-κB pathway

The placenta plays an important role in nutrient transport to maintain the growth and development of the embryo.Gestational diabetes mellitus(GDM),the most common complication during pregnancy,highly affects placental function in late gestation.Advanced glycation end-products(AGEs),a complex and heterogeneous group of compounds engaged by the receptor for AGEs(RAGE),are closely associated with diabetes-related complications.In this study,AGEs induced a decrease in the expression of tight junction(TJ)proteins in BeWo cells and increased the paracellular permeability of trophoblast cells by regulating RAGE/NF-κB.Sprague-Dawley(SD)rats injected with 100 mg/kg AGEs-rat serum albumin(RSA)via the tail vein from embryo day 2 were set as the placental barrier dysfunction model group(n=10).The effect of AGEs on placental permeability was determined using the Evans-Blue dye extravasation method.The ultrastructure of the placenta samples was observed by transmission electron microscopy.The effects of AGEs on the placenta were confirmed by treating rats with RAGE antagonist FPS-ZM1 and soluble forms of RAGE(sRAGE).AGEs treatment increased placental permeability and disrupted the tight junctions in pregnant rat placenta,but has no effect on blood glucose.The expression of TJ-related proteins,including ZO-1,Occludin,and Claudin 5,were downregulated after AGEs treatment.Further,AGEs treatment increased the expression of RAGE and nuclear factor-κB in the placenta of rats and upregulated the levels of vascular endothelial growth factor.The effects of AGEs on the placenta were blocked by RAGE antagonist FPS-ZM1 and sRAGE.This study demonstrates the mechanism underlying AGEs-induced disturbance in placental function in pregnant rats and highlights the potential of AGEs in the treatment of GDM.

Lactobacillus fermentum as a new inhibitor to control advanced glycation end-product formation during vinegar fermentation

The inhibitory activity of lactic acid bacteria(LAB)toward advanced glycation end-products(AGEs)during vinegar fermentation was studied,and its relationships with the substrate consumption,antioxidant capacity,total phenolic content,total flavonoid compounds,α-glucosidase,andα-amylase activity inhibition were evaluated.The vinegar was made from rice powder flour by liquid-state fermentation(LSF).The selected LAB strains were separately co-cultivated with Saccharomyces cerevisiae and Acetobacter pasteurianus 1.41 in alcoholic and acetic acid fermentation,respectively.Among 3 strains,Lactobacillus fermentum showed the strongest inhibitory effect on the formation of total fluorescent AGEs and carboxymethyl lysine(CML)/carboxyethyl lysine(CEL)in the fermentation process.The corresponding mechanisms included the acceleration of substrate consumtion,improvement of antioxidant activities,and inhibition ofα-glucosidase andα-amylase.In addition,the fluorescent AGEs and the CML/CEL were negatively correlated with the antioxidant activities,while theα-glucosidase andα-amylase activities were positively correlated with the total phenols and total flavonoids.Moreover,the variety of main flavor compounds increased,including esters,alcohols,phenols and acids.The results of the study support the potential use of screened LAB strains to inhibit the formation of fluorescent AGEs,CML and CEL on fermented products and in the food processing industry,without associated risks to consumers.

Contributions of the receptor for advanced glycation end products axis activation in gastric cancer

Compelling shreds of evidence derived from both clinical and experimental research have demonstrated the crucial contribution of receptor for advanced glycation end products(RAGE)axis activation in the development of neoplasms,including gastric cancer(GC).This new actor in tumor biology plays an important role in the onset of a crucial and long-lasting inflammatory milieu,not only by supporting phenotypic changes favoring growth and dissemination of tumor cells,but also by functioning as a pattern-recognition receptor in the inflammatory response to Helicobacter pylori infection.In the present review,we aim to highlight how the overexpression and activation of the RAGE axis contributes to the proliferation and survival of GC cells as and their acquisition of more invasive phenotypes that promote dissemination and metastasis.Finally,the contribution of some single nucleotide polymorphisms in the RAGE gene as susceptibility or poor prognosis factors is also discussed.

Individual and Combined Effects of Food Components in Attenuating the Formation of Advanced Glycation End Products (AGEs)

Advanced Glycation End Products (AGEs) have been associated as a possible cause in inflammation-mediated chronic diseases such as diabetes, Alzheimer’s and cardiovascular disorders. Thus, inhibition of AGE formation represents a prospective therapeutic target for the prevention and treatment of these complications. This study investigated the individual and combined effects of dietary ingredients, spices, on lowering AGEs formation in meat patties. In the study, Carboxymethyllysine (CML), a well-investigated AGE is used as a marker for AGEs and malondialdehyde (MDA) as an indicator for lipid peroxidation. Nine spices were selected based on their ability to inhibit the formation of AGEs at different stages of Maillard reactions. Individually, all the 9 selected spices significantly inhibited the formation of AGEs. Among the 33 combinations of spices, 26 combinations significantly inhibited the formation of AGEs. The highest reduction (84%) was found by the combination of Black Pepper-Rose-Cumin. The individual spices failed to significantly lower the MDA concentration;however, all 33 combinations were able to significantly reduce MDA concentration. The results of this study showed that spices when supplemented in combinations are more effective in inhibiting the formation of AGEs and in decreasing MDA concentration in meat patties.

Association of advanced glycation endproduct accumulation with overactive bladder in community-dwelling elderly: A cross-sectional Sukagawa study

Objective:This study aimed to evaluate the influence of advanced glycation end-product(AGE)accumulation on the prevalence and severity of overactive bladder(OAB)in community-dwelling elderly adults.Methods:We conducted a cross-sectional study involving 269 Japanese community dwellers aged≥75 years in 2015.AGE accumulation was non-invasively measured via skin autofluorescence(SAF)values using AGE Reader.The primary and secondary outcomes were the presence and severity of OAB evaluated using the Overactive Bladder Symptom Score(OABSS).Individuals with an urgency score of≥2 and sum score of≥3 were considered to have OAB.The associations of SAF with the prevalence and severity of OAB were assessed using logistic and linear regression models,respectively,adjusted for clinically important confounders.Results:The median age of participants was 78 years.Of 269 participants,110(40.9%)were men and 75(27.9%)had OAB.The median SAF was 2.2 arbitrary units(AUs).Increasing median SAF was observed with increasing age.Multivariable analysis revealed that SAF was not associated with either the likelihood of having OAB(odds ratio per AU=0.77,95%confidence interval:0.37-1.62)or the natural log-transformed OABSS(0 per AU=-0.07,95%confidence interval:-0.26-0.12).Conclusions:In this study,AGE accumulation,as assessed by SAF,was not associated with the prevalence and severity of OAB in Japanese community-dwelling elderly people aged≥75 years.

Inhibitory Effects of Several Spices on Inflammation Caused by Advanced Glycation Endproducts

Advanced glycation endproducts (AGEs) is implicated in the pathogenesis of diabetic complications. Inhibiting the formation of AGEs and interfering with AGEs-mediated inflammation are two practicable strategies for developing a dietary adjuvant against diabetic complications. This study evaluated the protective capacities against diabetic complications of several spices based on their inhibition of the formation of AGEs in an in vitro BSA/glucose system and on the AGEs-induced production of proinflammatory cytokine in RAW 264.7 macrophages. Among the tested spices, cinnamon exhibited most strongly inhibited both the formation of AGEs and the AGEs-induced production of nitric oxide, interleukin-6 and tumor necrosis factor-α. Additionally, correlative results revealed that the capacity of spices to inhibit the formation of AGEs is attributable to phenolic compounds and, in contrast, the capacity to inhibit AGEs-induced inflammation is attributable to condensed tannin. This investigation demonstrates the potential of cinnamon to serve as a dietary adjuvant against diabetic complications.

Effects of advanced glycosylation end products on proliferation and cytosolic free calcium in cultured rat aortic smooth muscle cells

目的：研究糖基化终产物（ＡＧＥＰ）对主动脉平滑肌细胞增殖的影响及其与［Ｃａ２＋］ｉ的关系．方法：采用同位素掺入法分别测定ＤＮＡ和蛋白质合成；Ｆｕｒａ２ＡＭ测定［Ｃａ２＋］ｉ．结果：ＡＧＥＰ以浓度、时间相关的方式促进［３Ｈ］ＴｄＲ与［３Ｈ］Ｌｅｕ掺入细胞，随ＡＧＥＰ作用时间、糖化时间延长，掺入率增加明显．ＡＧＥＰ增加［Ｃａ２＋］ｉ，与时间、浓度相关，但随ＡＧＥＰ作用时间延长（４０分钟后）而有所降低，ＢＳＡ修饰中葡萄糖浓度的增加，糖基化时间延长，［Ｃａ２＋］ｉ也呈上升趋势．结论：ＡＧＥＰ刺激平滑肌细胞增殖，并与细胞［Ｃａ２＋］ｉ浓度增加有关．

Expression of receptor for advanced glycosylation end products(AGEP)and inhibition of AGEP-induced cytosolic calcium elevationbydiltiazeminculturedrataorticsmoothmusclecels

目的：探讨培养的主动脉平滑肌细胞（ＡＳＭＣ）上是否表达糖基化终产物（ＡＧＥＰ）高亲性受体和地尔硫对ＡＧＥＰ升高胞浆游离钙的抑制．方法：用放射配基结合方法研究ＡＳＭＣ与ＡＧＥＰ的相互作用；用钙离子荧光指示剂Ｆｕｒａ２ＡＭ测定ＡＳＭＣ胞浆游离钙．结果：ＡＳＭＣ上有ＡＧＥＰ高亲和性受体表达，其解离常数为６５３±１５ｎｍｏｌ·Ｌ－１，最大结合容量１５７±００４ｎｍｏｌ／ｇ细胞蛋白；通过该受体介导，平滑肌细胞可内化、代谢ＡＧＥＰ．ＡＧＥＰ使胞浆游离钙呈浓度依赖性升高；地尔硫呈时间、浓度依赖性抑制此效应．结论：大鼠ＡＳＭＣ上有ＡＧＥＰ高亲和性受体表达；地尔硫可抑制ＡＧＥＰ介导的胞浆游离钙升高．

Advanced glycosylation end products increase diacylglycerol levels in cultured human umbilical vein endothelial cells

To study whether the diacylglycerol (Dia) signaling pathway is stimulated by advanced glycosylation end products (AGEP) and to test the effect of vitamin E and aminoguanidine (AG) on the elevation of Dia induced by AGEP in cultured human umbilical vein endothelial cells (HUVECs) Methods The effects of AGEP on Dia levels in cultured HUVEC were studied with radio enzymatic assay Quantitative measurements of 32 P phosphatidic acid were achieved by thin layer chromatography and autoradiography Results The Dia levels in HUVECs were increased by AGEP modified bovine serum albumin (AGEP BSA) in a dose dependent, biphasic manner The early phase was rapid and transient, peaking at 15?s; the late phase reached the maximal level at 10?min and then decayed slowly Dia levels in HUVEC exposed to different concentrations (50, 100 and 200?mg/L) of AGEP BSA (341±14, 678±16, and 873±18?pmol/L, respectively vs control 225±10?pmol/L) and AGEP BSA samples with various glycosylation times (4, 8 and 12 weeks) were significantly increased (270±12, 394±16, and 556±19?pmol/L) as compared with the controls 50 and 100?mmol/L of vitamin E can reduce AGEP BSA induced Dia levels from 873±18?pmol/L to 764±29 and 441±21?pmol/L in HUVEC, respectively In AG treated (100?mmol/L) groups, the same concentration (100 and 200?mg/L) of AGEP BSA induced elevation of Dia was decreased to 312±8 and 351±13?pmol/L, respectively Glycosylated low density lipoprotein (LDL) did not affect Dia levels Conclusion AGEP causes a robust stimulation of the Dia/protein kinase C pathway in HUVEC Vitamin E can attenuate the AGEP BSA induced elevation of Dia levels AG can suppress the ability of AGEP BSA to increase Dia levels in HUVEC

Effect of advanced glycosylation end products on activity of protein kinase C in human peripheral blood mononuclear cells

To investigate the effect of advanced glycosylation end products (AGEs) on the activity of protein kinase C (PKC) in human peripheral blood mononuclear cells (PBMC) and to observe whether aminoguanidine (AG) can influence the effect of AGEs Methods After PBMC were isolated from human peripheral blood and incubated with different concentrations of AGEs BSA for various periods, total PKC activity in PBMC was determined by measuring the incorporation of 32 P from [γ 32 P] ATP into a special substrate using Promega PKC assay kit Results AGEs BSA increased the total PKC activity in PBMC from 83 43±6 57?pmol/min/mg protein to 116 8±13 82?pmol/min/mg protein with a peak at 15?min AGEs BSA also increased the total PKC activity in a concentration dependent manner from 83 1±6 4?pmol/min/mg protein (control) to 119 1±13 3?pmol/min/mg protein (control vs AGEs BSA 400?mg/L, P <0 01) Furthermore, AGEs BSA induced an elevation of PKC activity in a glycosylating time related manner, from 80 9±8 2 (control) to 118 3±11 5?pmol/min/mg protein (glycosylation for 12 wk, P <0 01) The total PKC activity stimulated by AGEs BSA pretreated with AG (100, 200?mg/L) was markedly lower than that of AGEs BSA group not pretreated with AG ( P <0 05, P <0 01) Conclusions AGEs BSA increased the total PKC activity in PBMC in a concentration and incubation time dependent manner The ability of AGEs BSA to stimulate PKC activity was markedly decreased by pretreatment of AGEs BSA with AG

Inhibitory effect of eleven herbal extracts on advanced glycation end-products formation and aldose reductase activity

The formation of advanced glycation end-products （AGEs） and aldose reductase （AR） activity have been implicated in the development of diabetic complications. Our study sought to characterize the capacities of eleven herbal extracts against the formation of AGEs and the AR activity. An ultrahigh performance liquid chromatography and tandem mass spectrometry （UPLC-MS/MS） method was used for the detection of AR activity and the screening of AR inhibitors in this research. The amount of sorbitol from each analyte was directly detected using the multiple reaction monitoring mode and the sorbitol level could be reduced via the addition of an inhibitor. Moreover, the BSA/glucose （fructose） system was applied to investigate their inhibitory activities of AGEs formation in glycation model reactions. Compared with other screened herbs used in our study, Flos Sophorae lrnrnaturus and Radix Scutellariae seemed to be more effective on inhibiting the formation of AGEs and AR activity. The inhibiting capacities of herbal extracts against AR activity and AGEs formation may be correlated with the bioactive components of the herbal extracts. The differences were correlated with the amount of polyphenol and flavonoid components. In the study, we have investigated the potential anti-hyperglycemic bioactivity of eleven herbal extracts in vitro, which could provide a reference for further in vivo research in the prevention and treatment of diabetic complications.

Expression of platelet-endothelial cell adhesion molecule-1 in human umbilical vein endothelial cells by exposure to advanced glycosylation end products and inflammatory mediators

Objective To determine whether advanced glycosylation end products modified bovine serum albumin (AGEs-BSA) affects endothelial cell lateral junction protein, platelet-endothelial cell adhesion molecule-1 (PECAM-1) in the presence or absence of inflammatory mediators.Methods Cultured human umbilical vein endothelial cells (HUVECs) were exposed to AGEs-BSA for 6, 12, 24, and 36 hours, and exposed to AGEs-BSA glycosylated with different concentrations of glucose, tumor necrosis factord-α (TNF-α), interferon (IFN-γ), TNF-α + IFN-y and AGEs-BSA + TNF-α for 24 hours, respectively. Expression of PECAM-1 mRNA was measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) with β-actin as an internal standard, and sequencing of RT-PCR products was performed to confirm the specificity of amplification for PECAM-1 gene. The endothelial cell surface expression of PECAM-1 was determined by flow cytometry (FCM).Results There were no significant changes in the expression of PECAM-1 mRNA and protein when the cells were exposed to AGEs-BSA with different concentrations or periods ( P>0. 05). However, PECAM-1 expression was reduced in the cells treated with TNF-α, IFN-y, TNF-α + IFN-γ and AGEs-BSA + TNF-α. The level of PECAM-1 treated with AGEs-BSA + TNF-α was lower than that of TNF-α treated alone (P<0. 01).Conclusions AGEs-BSA had no effect on the expression of PECAM-1 mRNA and protein in cultured HUVEC. With the presence of inflammatory mediator TNF-α, AGEs-BSA decreased the level of PECAM-1, which might reduce the adhesion interaction between adjacent endothelial cells, enhance the permeability of endothelial cells, and might be implicated in the endothelial dysfunction and pathogenesis of atherosclerosis in patients with diabetes mellitus. The significance of this phenomenon in intracellular signal transduction remains to be determined.

Complications in the spine associated with type 2 diabetes:The role of advanced glycation end-products

Type 2 diabetes mellitus(T2D)is an increasingly prevalent disease with numerous comorbidities including many in the spine.T2D is strongly linked with vertebral fractures,intervertebral disc(IVD)degeneration,and severe chronic spinal pain.Yet the causative mechanism for these musculoskeletal impairments remains unclear.The chronic hyperglycemic state in T2D promotes the formation of advanced glycation end-products(AGEs)in tissues,and the accumulation of AGEs may play a role in musculoskeletal complications by modifying the extracellular matrix,impairing cellular homeostasis,and perpetuating an inflammatory cascade via its receptor(RAGE).The AGE and RAGE associated alterations in extracellular matrix composition and morphological features of the vertebral bodies and IVDs are likely contributors to the incidence and severity of spinal pathologies in T2D.This review will broadly examine the effects of AGEs on tissues in the spine in the context of T2D,with an emphasis on the changes in the vertebrae and the IVD.Along with the clinical and epidemiological findings,we will provide an overview of preclinical rodent models of T2D that exhibit deficits in the IVD and vertebral bone.Elucidating the role of AGEs and RAGE will be crucial for understanding the disease mechanisms and translation therapies of musculoskeletal pathologies in T2D.