Existence of advanced glycation / lipoxidation end-products in parenteral nutrition solutions and effects of infusion conditions on their levels

Abstract Infusion solutions must be stable from the production stage until the infusion stage. Some infusion fluids contain degradation products, known as advanced glycation end products (AGEs); however, it is unknown whether AGEs exist in parenteral nutrition solutions. We aimed to investigate this question and test the effect of infusion conditions on AGE formation in parenteral nutrition solution. Nine parenteral nutrition solutions were supplied by the pharmacy with which we collaborated. To simulate the infusion conditions, the solutions were held in a patient room with standard lighting and temperature for 24 hours. Samples were taken at the beginning (group A) and the end (24th hour, group B) of the infusion period. The degradation products were 3-deoxyglucosone, pentosidine, N-carboxymethyl lysine, and 4-hydroxynonenal, which we investigated by high-performance liquid chromatography-mass spectrometry (LC-MS) and Q-TOF LC/MS methods. Two of four degradation products, 4-hydroxynonenal and N-carboxymethyl lysine, were detected in all samples, and Group B had higher levels of both compounds compared to Group A, who showed that the quantities of these compounds increased in room conditions over time. The increase was significant for 4-hydroxynonenal (p=0.03), but not for N-carboxymethyl lysine (p=0.23). Moreover, we detected in the parenteral nutrition solutions a compound that could have been 4-hydroxy-2-butynal or furanone

Antiglycation and antioxidant activities of the crude extract and saponin fraction of Tribulus terrestris before and after microcapsule release / 中西医结合学报

OBJECTIVE@#The present study investigated antiglycation and antioxidant activities of crude dry extract and saponin fraction of Tribulus terrestris. It also developed a method of microencapsulation and evaluated antiglycation and antioxidant activities of crude dry extract and saponin fraction before and after microcapsule release.@*METHODS@#Antiglycation activity was determined by relative electrophoretic mobility (REM), free amino groups and inhibition of advanced glycation end-product (AGE) formation. Antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric ion-reducing antioxidant power (FRAP), nitric oxide (NO) and thiobarbituric acid reactive species (TBARS) tests. Microcapsules were prepared using maltodextrin as wall material and freeze-drying as encapsulation technique. Morphological characterization of microcapsules was evaluated by scanning electron microscopy, and encapsulation efficiency and microcapsule release were determined by total saponins released. Antiglycation and antioxidant assays were performed using crude dry extract and saponin fraction of T. terrestris before and after release.@*RESULTS@#Saponin fraction showed an increase of 32.8% total saponins. High-performance liquid chromatography-mass spectrometry analysis showed the presence of saponins in the obtained fraction. Antiglycation evaluation by REM demonstrated that samples before and after release presented antiglycation activity similar to bovine serum albumin treated with aminoguanidine. Additionally, samples inhibited AGE formation, highlighting treatment with saponin fraction after release (89.89%). Antioxidant tests demonstrated antioxidant activity of the samples. Crude dry extract before encapsulation presented the highest activities in DPPH (92.00%) and TBARS (32.49%) assays. Saponin fraction before encapsulation in FRAP test (499 μmol Trolox equivalent per gram of dry sample) and NO test (15.13 μmol nitrite formed per gram of extract) presented the highest activities.@*CONCLUSION@#This study presented antiglycation activity of crude dry extract and saponin fraction of T. terrestris, besides it demonstrated promising antioxidant properties. It also showed that the encapsulation method was efficient and maintained biological activity of bioactive compounds after microcapsule release. These results provide information for further studies on antidiabetic and antiaging potential, and data for new herbal medicine and food supplement formulations containing microcapsules with crude extract and/or saponin fraction of T. terrestris.

Research on Molecular Mechanism of Fructus Ligustri Lucidi against Osteoporosis based on Network Pharmacology

Abstract TCMSP platform of systematic pharmacology of traditional Chinese medicine This study aimed to investigate the molecular mechanism of Fructus Ligustri Lucidi (NZZ, Chinese abbreviation) against osteoporosis (OP) by means of network pharmacology.ChemDraw Professional 15.1 software and Molinspiration Smiles database were used to draw the chemical formulas of the components. The active ingredients and related target proteins of NZZ were searched in platform of systematic pharmacology of traditional Chinese medicine database, Drugbank, Therapeutic Target Database, SymMap and other databases. Gene Ontology(GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were carried out on the selected target through Enrichr and KEGG Automatic Annotation databases, and their mechanism was studied. A total of 29 compounds and 140 corresponding targets, including 14 key targets and 14 protein factors in protein-protein interaction core network were obtained. The key targets were tumor necrosis factor(TNF), interleukin(IL)-6R and sestrogen receptor alpha. The number of GO items was 466 (P<0.05), including 399 items of biological process (BP), 54 items of cell composition (MF) and 13 items of molecular function (CC). KEGG pathway enrichment screened 85 signaling pathways (P<0.05), including the IL-17 signaling pathway, TNF signaling pathway, advanced glycation end products and their receptors signaling pathway and cAMP signaling pathway. The active ingredients of NZZ. exert their anti-OP effects through multi-components, multi-targets and multi-pathways, which can provide new evidence for further study of their anti-OP mechanism.

Associations of high-mobility group box 1 and receptor for advanced glycation end products with acute lung injury in patient with acute aortic dissection

SUMMARY OBJECTIVE: To investigate the associations of high-mobility group box 1 and its specific receptor, receptor for advanced glycation end products with acute lung injury in patients with acute aortic dissection. METHODS: A total of 96 acute aortic dissection patients were divided into acute aortic dissection with acute lung injury group (38 cases) and acute aortic dissection without acute lung injury group (58 cases), according to partial pressure of oxygen/fraction of inspired oxygen. In addition, 44 healthy individuals were selected for the control group. The blood samples were taken. The serum high-mobility group box 1 and receptor for advanced glycation end products levels were detected by enzyme-linked immunosorbent assay, and the partial pressure of oxygen/fraction of inspired oxygen was measured. RESULTS: 24 h after admission, the high-mobility group box 1 and receptor for advanced glycation end products levels in acute aortic dissection with acute lung injury and acute aortic dissection without acute lung injury groups were significantly higher than those in the control group, respectively (p<0.05), and each index in acute aortic dissection with acute lung injury group was significantly higher than that in acute aortic dissection without acute lung injury group (p<0.05). At each time point within 96 h after admission, compared with acute aortic dissection without acute lung injury group, in acute aortic dissection with acute lung injury group, the high-mobility group box 1 and receptor for advanced glycation end products levels were increased, respectively, and the partial pressure of oxygen/fraction of inspired oxygen was decreased. The correlation analysis showed that, in acute aortic dissection patients, the high-mobility group box 1 and receptor for advanced glycation end products levels were negatively correlated with partial pressure of oxygen/fraction of inspired oxygen, respectively (p<0.05). CONCLUSIONS: The serum high-mobility group box 1 and receptor for advanced glycation end products levels may be associated with the occurrence of acute lung injury in acute aortic dissection patients. Monitoring the high-mobility group box 1 and receptor for advanced glycation end products levels can evaluate the risk of acute aortic dissection with acute lung injury.

AGEs accumulation is related to muscle degeneration and vascular calcification in peritoneal dialysis patients / O acúmulo de AGEs está relacionado à degeneração muscular e calcificação vascular em pacientes em diálise peritoneal

Abstract Background: Patients with chronic kidney disease (CKD) are affected by dynapenia, sarcopenia, and vascular calcification. Advanced glycation end products (AGEs) may accumulate in peritoneal dialysis (PD) patients and favor sarcopenia via changes in collagen cross-linking, muscle protein breakdown, and the calcification of arterial smooth muscle cells via p38-MAPK activation. The aim of this study is to explore the relationships between AGEs, muscle degeneration, and coronary artery calcification. Methods: This was a clinical observational study in patients with CKD undergoing PD, in which serum and skin AGEs (AGEs-sAF), cumulative glucose load, muscle strength and functional tests, muscle ultrasounds with elastography, coronary artery calcium (CAC) quantification, and muscle density by multislice computed tomography were measured. Results: 27 patients aged 48±16 years, dialysis vintage of 27±17 months, had AGEs-sAF levels of 3.09±0.65 AU (elevated in 13 [87%] patients), grip strength levels of 26.2±9.2 kg (11 [42%] patients with dynapenia), gait speed of 1.04±0.3 m/s (abnormal in 14 [58%] patients) and "timed-up-and-go test" (TUG) of 10.5±2.2s (abnormal in 7 [26%] patients). Correlations between AGEs-sAF levels and femoral rectus elastography (R=-0.74; p=0.02), anterior-tibialis elastography (R= -0.68; p=0.04) and CAC (R=0.64; p=0.04) were detected. Cumulative glucose load correlated with femoral rectal elastography (R=-0.6; p=0.02), and serum glycated hemoglobin concentrations correlated with psoas muscle density (R= -0.58; p=0.04) and CAC correlated with psoas muscle density (R=0.57; p=0.01) and lumbar square muscle density (R=-0.63; p=0.005). Conclusions: The study revealed associations between AGEs accumulation and lower muscle stiffness/density. Associations that linked muscle degeneration parameters with vascular calcification were observed.

Resumo Histórico: Pacientes com doença renal crônica (DRC) são afetados pela dinapenia, sarcopenia e calcificação vascular. Produtos finais da glicação avançada (AGEs) podem se acumular em pacientes em diálise peritoneal (DP) e favorecer a sarcopenia por meio de alterações em ligações cruzadas do colágeno, quebra da proteína muscular e calcificação das células do músculo liso arterial por meio da ativação da p38-MAPK. O objetivo deste estudo é explorar as relações entre AGEs, degeneração muscular e calcificação da artéria coronária. Métodos: Este foi um estudo clínico observacional em pacientes com DRC submetidos à DP, no qual foram medidos os AGEs séricos e teciduais (AGEs-sAF), a carga cumulativa de glicose, a força muscular e testes funcionais, ultrassonografias musculares com elastografia, quantificação do cálcio da artéria coronária (CAC), e a densidade muscular por tomografia computadorizada multislice. Resultados: 27 pacientes com idade entre 48±16 anos, tempo de diálise entre 27±17 meses, tinham níveis de AGEs-sAF de 3,09±0,65 UA (elevado em 13 [87%] pacientes), níveis de força de preensão de 26,2±9,2 kg (11 [42%] pacientes com dinapenia), velocidade de marcha de 1,04±0,3 m/s (anormal em 14 [58%] pacientes) e teste "timed-up-and-go" (TUG) de 10,5±2,2s (anormal em 7 [26%] pacientes). Foram detectadas correlações entre os níveis AGEs-sAF e a elastografia do reto femoral (R=-0,74; p=0,02), a elastografia tibial anterior (R= -0,68; p=0,04) e a CAC (R=0,64; p=0,04). A carga cumulativa de glicose se correlacionou com a elastografia do reto femoral (R=-0,6; p=0,02), as concentrações séricas de hemoglobina glicada se correlacionaram com a densidade muscular do psoas (R= -0,58; p=0,04) e o CAC se correlacionou com a densidade do músculo psoas (R=-0,57; p=0,01) e a densidade do músculo quadrado lombar (R=-0,63; p=0,005). Conclusões: O estudo revelou associações entre o acúmulo de AGEs e menor rigidez/densidade muscular. Foram observadas associações que ligavam parâmetros de degeneração muscular com a calcificação vascular.

Association of RAGE gene polymorphisms with MHR ratio and heart rate variability among patients with coronary heart disease / 中华医学遗传学杂志

OBJECTIVE@#To assess the association of polymorphisms of receptor of advanced glycation end products (RAGE) gene, monocyte to high-density lipoprotein cholesterol ratio (MHR) and variability of heart rate among patients with coronary heart disease (CHD).@*METHODS@#120 patients with CHD and 120 healthy individuals were respectively selected as the observation group and the control group. Allelic and genotypic differences of -429T>C, 1704G>T, 82G>S, MHR ratio and heart rate variability between the two groups and patients with different severity were analyzed. The correlation between their genotypes and MHR ratio and heart rate variability was analyzed.@*RESULTS@#The 82G>S polymorphism of the RAGE gene and the allelic difference between the two groups and patients with different severity were statistically significant (P< 0.05). Compared with the control group and patients with mild to moderate phenotype, monocyte, total cholesterol, triglyceride, low density lipoprotein, MHR, low frequency in the observation group and patients with severe symptoms were significantly higher, while their high density lipoprotein, standard deviation of NN intervals (SDNN), standard deviation average of NN intervals (SDANN), root mean square successive differences, percentage of differences exceeding 50ms between adjacent normal number of intervals (PMN50), high frequency (HF) were significantly lower. The gene frequencies of G-Gly-T, T-Gly-T, G-Ser-T and G-Gly-C were correlated with SDNN, SDANN, rMSSD, PMN50, HF and MHR, but negatively correlated with low frequency.@*CONCLUSION@#Polymorphisms of the RAGE gene in patients with coronary heart disease are associated with the MHR ratio and heart rate variability, which can be used as markers for the diagnosis and efficacy evaluation.

Effect of advanced glycation end products on autophagic ability in osteoblasts / 中南大学学报(医学版)

OBJECTIVES@#Excessive production of AGEs in diabetic patients will affect the normal function of osteoblasts, and this process may be related to autophagy of osteoblasts. This study aims to explore the effect of advanced glycation end products (AGEs) on autophagic activity during osteogenic differentiation in rat bone marrow mesenchymal stem cells (BMSCs).@*METHODS@#BMSCs were isolated and cultured in vitro, treated with different concentrations (0, 50, 100, 200, and 400 mg/L) of AGEs for different time (3, 6, 12, 24, 48, and 72 h). The proliferation activity was detected by CCK-8 method. The mRNA and protein expression levels of Beclin1 and LC3 in cells were detected by real-time PCR and Western blotting, respectively.The autophagic vacuoles were observed under the transmission electron microscope. The cells were treated with autophagy promoter rapamycin or autophagy inhibitor 3MA. After 7 days of osteogenic induction, we performed alkaline phosphatase (ALP) staining and real-time PCR to detect the mRNA expression levels of osteogenesis-related genes.@*RESULTS@#In the low-concentration groups, the proliferation activity in BMSCs was increased (@*CONCLUSIONS@#Low concentration of AGEs can enhance the proliferative activity of BMSCs and promote osteogenic differentiation by accelerating autophagy. High concentration of AGEs can suppress the proliferation of BMSCs and inhibit osteogenic differentiation by reducing autophagy.

Mechanism of advanced glycation end products inhibiting the proliferation of peripheral blood mononuclear cells and osteoblasts in rats / 北京大学学报(医学版)

OBJECTIVE@#To explore the mechanism of nuclear factor-kappa B (NF-κB), phosphatidylinositol 3-kinase (PI3K)/protein kinase B(PKB/Akt) and mitogen-activated protein kinase (MAPK) signaling pathways after intervention of advanced glycosylation end products (AGEs) in peripheral blood mononuclear cells (PBMCs) and osteoblasts (OB) in rats, so as to provide certain experimental basis and theoretical basis for further research on the clinical treatment of periodontal tissue inflammation caused by diabetes mellitus.@*METHODS@#AGEs were prepared, PBMCs and OB were isolated and cultured in vitro. CCK-8 was used to detect the cell viability intervened by different concentrations and time of AGEs. Western blot and qRT-PCR were used to detect the expression changes of genes related to NF-κB, PI3K/PKB and MAPK signaling pathways.@*RESULTS@#OB and PBMCs were successfully isolated and cultured in vitro. The activity of PBMCs and OB cells was significantly correlated with the concentration, time and interaction of AGEs. With the increase of AGEs concentration and time, the activity of PBMCs and OB cells significantly decreased (P < 0.001). AGEs stimulation significantly increased the expression of NF-κB in PBMCs and the contents of tumor necrosis factor α(TNF-α), interleukin-1β(IL-1β) (P < 0.01). TNF-α, IL-1β levels were significantly reduced after inhibition of NF-κB pathway (P < 0.01). NF-κB p65, JNK, and p38 phosphorylated and non-phosphorylated proteins increased significantly after AGEs stimulation of OB (P < 0.05). The phosphorylated protein expression of IκB was significantly increased, while the expression of non-phosphorylated protein was decreased (P < 0.01).The expressions of NF-κB p65, JNK, and IκB were significantly increased at the mRNA levels, and the expressions of IκB mRNA were significantly decreased (P < 0.05). There was no difference in the expression of Akt in either phosphorylated or non-phosphorylated proteins or at the mRNA level (P>0.05). With the addition of MAPK signaling pathway inhibitors, the phosphorylation and non-phosphorylated protein expressions of NF-κB p65, p38 and JNK were significantly reduced, and the phosphorylated protein of IκB was significantly decreased and the non-phosphorylated protein was significantly increased compared with the group with AGEs alone (P < 0.05). The results of qRT-PCR showed that the expression of IκB increased significantly after the addition of the JNK pathway blocker (P < 0.05), and the expression of NF-κB p65, p38 and JNK decreased, but the difference was not significant (P>0.05). While NF-κB p65, p38 and JNK were significantly decreased and IκB was significantly increased in the AGEs group after the addition of the p38 pathway blocker (P < 0.05). At this time, there was still no significant change in the expression of Akt at the protein level and mRNA level (P>0.05).@*CONCLUSION@#AGEs inhibit the proliferation of PBMCs and OB, and the NF-κB and MAPK pathways are likely involved in regulating this process, but not the PI3K/PKB pathway.

Inibição combinada do receptor AT1 e produtos finais de glicação avançada na nefropatia diabética / Combined inhibition of AT1 receptor and advanced glycation end products in diabetic nephropathy

O diabetes mellitus (DM) é um grande problema de saúde pública, que afeta cerca de 463 milhões de pessoas no mundo e pode alcançar 700 milhões de pessoas até 2045. A nefropatia é uma das complicações microvasculares do diabetes e a maior causa de insuficiência renal. Uma vez que a ativação do receptor AT1 pela angiotensina II causa vasoconstrição da artéria aferente, e que o acúmulo de produtos finais de glicação avançada (AGEs) causam glicotoxicidade intracelular de células mesangiais, podocitárias e tubulares, foi avaliado se o tratamento combinado de olmersatana (OLM) e piridoxamina (PYR) é capaz de melhorar a nefropatia diabética quando comparado aos tratamentos isolados. Para isto, o diabetes mellitus experimental foi induzido em 50 camundongos C57BL/6 pela administração de estreptozotocina (50 mg/kg/dia via intraperitoneal por 5 dias). Os animais foram divididos em cinco grupos: controle, diabéticos, diabéticos tratados com OLM (20 mg/Kg/dia), diabéticos tratados com PYR (400 mg/Kg/dia) e diabéticos tratados com OLM e PYR (20 mg/Kg/dia e 400 mg/Kg/dia, respectivamente) Os tratamento durou 16 semanas. Como resultado, os camundongos que receberam STZ desenvolveram hiperglicemia e doença renal, diminuição de peso, poliúria, polidipsia, polifagia, e albuminúria, além de aumento de frutosamina, ferro, uréia e fosfatase alcalina na urina, diminuição da atividade de catalase no rim e aumento de excreção dos AGEs na urina. Histologicamente, houve aumento de área glomerular e do espaço de BowmanO tratamento com OLM atenuou a albuminúria e atenuou o declínio da função renal, uma vez que o OLM melhorou a polidipsia, polifagia, poliúria, marcadores bioquímicos de disfunção renal e parâmetros histológicos, apesar de não apresentar ação sobre a fosfatase alcalina, uréia, ferro, frutosamina e ácido úrico. O tratamento isolado com PYR melhorou a maioria dos parâmetros alterados pela doença, entre eles a ingestão alimentar, ingestão hídrica, volume urinário, creatinina sérica, excreção de albumina na urina, ACR, AGEs no tecido renal e urina, ureia na urina e todos os parâmetros morfológicos analisados, contudo sem efeito sobre a fosfatase alcalina, ferro, frutosamina e ácido úrico. O tratamento combinado (PYR e OLM) melhorou a polifagia, polidipsia e poliúria comparado aos animais diabéticos sem tratamento, entretanto não houve diferença comparado a cada tratamento isolado. Os parâmetros histológicos e bioquímicos (creatinina no soro, albumina na urina, ACR e uréia) também apresentaram melhorara em relação aos animais diabéticos sem tratamento, mas não em relação aos animais em tratamento isolado. Tanto PYR quanto OLM não influenciaram a excreção de AGEs na urina. Esses dados nos levam a concluir que o tratamento combinado não ofereceu efeitos benéficos adicionais quando comparado aos tratamentos isolados, e que o tratamento que mais ofereceu benefícios foi o tratamento isolado com PYR nos parâmetros metabólicos, morfológicos e de função renal. (AU)

Effects of vitamin C local application on ligature-induced periodontitis in diabetic rats

Abstract Objective: This study evaluated the effects of local vitamin C treatment on tissue advanced glycation end products (AGE), interleukin (IL)-6, 8-hydroxy-2-deoxyguanosine (8-OHdG), and matrix metalloproteinases (MMP)-8 in tissues; serum C-terminal telopeptide fragments (CTX); and alveolar bone loss (ABL) in rats. Methodology: 35 male Sprague Dawley rats were divided equally into five groups: 1) control (C), 2) experimental periodontitis (P), 3) experimental diabetes (D), 4) experimental diabetes and experimental periodontitis (D + P), and 5) experimental diabetes-experimental periodontitis-locally applied vitamin C (D + P + LvitC). Diabetes was induced in rats with alloxan monohydrate, after which periodontitis was induced by ligature placement in the right mandibular first molar teeth for 11 days. In the treatment group, vitamin C was administered locally three times with two-days interval after ligature removal. The animals were sacrificed, and the samples were analyzed histometrically and immunohistochemically. Results: CTX, 8-OHdG, and AGE values significantly decreased in the treatment group compared to the D + P group. IL-6 and MMP-8 values decreased in the treatment group compared to the D + P group, but this is not significant. ABL was significantly reduced by the local delivery of vitamin C. Conclusion: This study reveals that vitamin C treatment may be beneficial to reduce serum CTX and gingival MMP-8 levels, oxidative stress, inflammation, and AGE accumulation in periodontal tissue. Vitamin C may be an immunomodulator and antioxidant locally applied in the treatment of periodontitis to reduce the adverse effects of diabetes in periodontal tissues.

Reacción de Maillard: Efectos patogénicos / Maillard reaction. Pathogenic effects

La cocción de los alimentos a altas temperaturas en calor seco, produce ciertas modificaciones organolépticas que los hace especialmente apetecibles y objetos de adicción. Esto es resultado de la reacción de Maillard, o glicación, que se produce por unión no enzimática del grupo carbonilo, de azúcares reductores como glucosa y fructosa, con el grupo amino de proteínas y ácidos nucleicos. Junto a los cambios físicos, cambia la estructura química y la función de estos aductos, denominados también glicotoxinas. Además de la glicación exógena, generada durante la cocción de los alimentos, recientemente ha sido referida la glicación in situ, en la luz intestinal, durante la digestión, cuando determinados alimentos no glicados se combinan en el momento de su ingestión. A esto se agrega la glicación endógena extracelular relacionada con la glucosa sanguínea y la intracelular, con metabolitos de la glucólisis y de la fructosa. Desde la década del 70, con el remplazo en gran medida de la sacarosa por fructosa, significativamente más reactiva que la glucosa, aumentó la presencia de productos de glicación en alimentos procesados y bebidas gaseosas. Están documentados sus efectos patogénicos como contribuyentes al estrés oxidativo y a la inflamación, especialmente en diabetes, insuficiencia renal y enfermedad cardiovascular y están siendo explorados en otras enfermedades crónicas, como procesos neurodegenerativos y envejecimiento temprano. Se describen medidas para preservar la salud, atendiendo medios de cocción y procesamiento de los alimentos y recomendaciones sobre hábitos de vida e ingesta de antioxidantes para acción inhibitoria o antagónica sobre las glicotoxinas.

Certain organoleptic modifications by way of processing and cooking foods at high temperatures in dry heat, make them especially appetizing and objects of addiction. It results from Maillard reaction, or glycation, consisting of the non-enzymatic union between carbonyl groups, mainly from reducing sugars as glucose and fructose, with the amino group of proteins and nucleic acids. In addition to physical changes, also the chemical structure and function of these compounds are changed. Besides exogenous glycation generated during the cooking of foods, recently in situ glycation has been reported in the intestinal lumen during digestion, when certain non-glycated foods are combined with fructose at the time of ingestion. In addition, endogenous glycation, which correlates in the extracellular mainly with blood glucose and in the intracellular with glycolysis metabolites and fructose, is specially significant. Since the 70s, with the frequent sucrose replacement by fructose, much more reactive than glucose, the presence of glycation products in processed foods and soft drinks increased.Pathogenic effects of these compounds, also called glycotoxins, are known to contribute to oxidative stress and inflammation. This increases progression of chronic diseases, well documented in diabetes, renal insuficiency, cardiovascular disease and aging process, and are being explore d in many other chronic diseases as neurodegenerative disorders and early aging. Based on the knowledge achieved so far, measures to preserve health are described by attending ways of cooking and processing foods, besides recommendations for life habits and antioxidants dietary intakes for inhibition or antagonism on glycotoxins.

Screening for active components of Sophorae Flos on inhibiting AGEs formation based on non-enzymatic glycation reaction / 中国中药杂志

Sugar-poison caused blood-heat is the pathological basis of many complications of diabetes. Advanced glycation end products( AGEs) are considered as the potential glycotoxic factor that can cause blood-heat. Sophorae Flos hold the effect of removing pathogenic heat from blood. In this study,chromatographic non-enzymatic glycation reaction system of bovine serum albumin( BSA)/methylglyoxal( MGO) and Sophorae Flos was established to identify active components in Sophorae Flos inhibiting AGEs formation. The HPLC was used to analyze chromatograms before and after the incubation of Sophorae Flos and methylglyoxal. Changes of chromatographic peaks of eight compounds was found. It is speculated that this change may be due to new substance produced by the reaction of active components in Sophorae Flos and methylglyoxal,and these active components may be flavonoid component rutin. Further investigation for the effects of rutin and MGO reaction( 1 ∶ 1,1 ∶ 3,3 ∶ 1) for 6 days on the formation of AGEs was performed. The results showed that the inhibition activity of rutin on AGEs production was most obvious when the reaction ratio was 1 ∶3,and the most inhibition was in 24 h and stabilized after 3 d. The product of the reaction of rutin with MGO was identified by LC-ESI-MS/MS,which indicated that the newly formed seven substances were the mono-and di-MGO adducts of rutin. This study showed that rutin is the active component on Sophorae Flos for removing pathogenic heat from blood by forming new compounds to inhibit the formation of sugar poison products,which provides reference for rational application of Sophorae Flos.

Ursane derivatives isolated from leaves of Hylocereus undatus inhibit glycation at multiple stages / 中国天然药物

The present study was designed to evaluate the therapeutic potential of bioactive compounds from chloroform extract of the leaves of Hylocereus undatus in the formation of advanced glycation end products (AGEs) in vitro. Bioactivity-guided fractionation of chloroform extract from Hylocereus undatus afforded two novel 12-ursen-type triterpenes, 3β, 16α, 23-trihydroxy-urs-12- en-28-oic acid (1) and 3β, 6β, 19α, 22α-tetrahydroxy-urs-12-en-28-oic acid (2), as well as four known triterpenes 2α, 3β, 23-tetrahydroxy-urs-11-en-28-oic acid (3), 3β-acetoxy-28-hydroxyolean-12-ene (4), 3β, 16α-dihidroxyolean-12-ene (5) and 3β-acetoxy-olean-12-ene (6). Our results revealed that triterpenes 1-3 were able to inhibit the formation of AGEs in all tested assays. The data indicated that the triterpenes had inhibitory activity at the múltiple stages of glycation and that there might be a high potential for decreasing protein oxidation and protein glycation that can enhance glycative stress in diabetic complications.

Ursane derivatives isolated from leaves of Hylocereus undatus inhibit glycation at multiple stages / 中国天然药物

The present study was designed to evaluate the therapeutic potential of bioactive compounds from chloroform extract of the leaves of Hylocereus undatus in the formation of advanced glycation end products (AGEs) in vitro. Bioactivity-guided fractionation of chloroform extract from Hylocereus undatus afforded two novel 12-ursen-type triterpenes, 3β, 16α, 23-trihydroxy-urs-12- en-28-oic acid (1) and 3β, 6β, 19α, 22α-tetrahydroxy-urs-12-en-28-oic acid (2), as well as four known triterpenes 2α, 3β, 23-tetrahydroxy-urs-11-en-28-oic acid (3), 3β-acetoxy-28-hydroxyolean-12-ene (4), 3β, 16α-dihidroxyolean-12-ene (5) and 3β-acetoxy-olean-12-ene (6). Our results revealed that triterpenes 1-3 were able to inhibit the formation of AGEs in all tested assays. The data indicated that the triterpenes had inhibitory activity at the múltiple stages of glycation and that there might be a high potential for decreasing protein oxidation and protein glycation that can enhance glycative stress in diabetic complications.

Evaluation of in vitro antioxidant, antiglycation and antimicrobial potential of indigenous Myanmar medicinal plants / 中西医结合学报

<p><b>OBJECTIVE</b>Myanmar has a long history of using medicinal plants for treatment of various diseases. To the best of our knowledge there are no previous reports on antiglycation activities of medicinal plants from Myanmar. Therefore, this study was aimed to evaluate the antioxidant, antiglycation and antimicrobial properties of 20 ethanolic extracts from 17 medicinal plants indigenous to Myanmar.</p><p><b>METHODS</b>In vitro scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), superoxide (SO) radicals were used to determine the antioxidant activities. Folin-Ciocalteu's method was performed to determine the total phenolic content. Antiglycation and antimicrobial activities were detected by bovine serum albumin-fluorescent assay and agar well diffusion method.</p><p><b>RESULTS</b>Terminalia chebula Retz. (Fruit), containing the highest total phenolic content, showed high antioxidant activities with inhibition of 77.98% ± 0.92%, 88.95% ± 2.42%, 88.56% ± 1.87% and 70.74%± 2.57% for DPPH, NO, SO assays and antiglycation activity respectively. It also showed the antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans with inhibition zone of 19, 18, 17, 25 and 15 mm, respectively. Garcinia mangostana Linn. showed the strongest activities for SO and antiglycation assays with inhibition of 93.68% ± 2.63% and 82.37% ± 1.78%. Bark of Melia sp. was the best NO radical scavenger with inhibition rate of 89.39%± 0.60%.</p><p><b>CONCLUSION</b>The results suggest that these plants are potential sources of antioxidants with free radical-scavenging and antiglycation activities and could be useful for decreasing the oxidative stress and glycation end-product formation in glycation-related diseases.</p>

Evaluación piloto de la reducción de niveles séricos de productos de glicación avanzada (AGEs) sobre la electrofisiología de la visión, en pacientes con diabetes mellitus tipo 2 / Pilot evaluation of the serum levels reduction of advanced glication products (AGEs) on the vision electrophysiology in type 2 diabetic patients

BACKGROUND: Diabetic vascular complications are associated with elevated concentrations of advanced glycation end-products (AGEs). These substances can be originated endogenously by hyperglycaemia and oxidative stress, but also by dietary intake. There is indirect evidence suggesting that these complications can be prevented by lowering AGEs levels by dietary or pharmacological interventions, however its clinical benefits are still not clear enough because this would require long periods of treatment. Specific neuro-ophthalmologic tests like Multifocal Electroretinogram (MFERG) and visual evoked potentials (VEP) can detect retinal and myelinic nerve early changes, and thus could represent good methods to study the results of certain interventions in shorter lapses. The aim of this preliminary study was to evaluate the effects of a pharmacological intervention designed to lower AGEs levels, on these variables. PATIENTS AND METHODS: We included 7 patients with type 2 diabetes (DM2), with more than 5 and less than 10 years of disease, without clinically evident micro and macrovascular disease, without renal failure, hypothyroidism nor vitamin B12 deficiency, whose AGEs dietary intake was moderately elevated or high (according to dietary recalls). Upon admission, a clinical evaluation, urine and blood samples were obtained for routine labs, plus ultrasensitive C Reactive Protein (usCRP) as an inflammatory marker, and carboxymethyl-lysine (CML) as representative of AGEs. Then a complete ophthalmologic evaluation was performed, including fundus, MFERG and VEP. After the initial evaluation, placebo capsules were prescribed (12 daily capsules, 4 with each main meal) during 3 months, repeating the same initial evaluation at completion of this period. Then the active treatment followed, with capsules containing cholestyramine (4 capsules containing 500 mg each, totaling 6 g per day). Patients were cited each month, to register adverse events and repeating the same evaluation after this second 3 months period. RESULTS: The sample was composed of 2 male patients, mean age was 55.1 ± 3.8 years, and diabetes was managed with metformin plus other oral agents or o insulin (4 cases). In addition, 4 patients received lipid lowering and 4 antihypertensive drugs. Metabolic control and lipid levels were variable (ranges of HbA1c 6.2-8.4%, LDL cholesterol 45-141 mg/dL, triglycerides 70-220 mg/dL). AGEs levels represented by CML were highly variable (median 31.7, range min-max 3.4-58.9 ug/uL). Basal usCRP was also variable (median 405.9, range min-max 265.6-490.7 mg/L). The treatment was well tolerated, except for mild constipation associated with cholestiramine intake. No significant changes in electroretinography or evoked potentials were observed when comparing the initial placebo period with cholestyramine treatment. A significant increase in triglyceride levels and decrease of vitamin D levels after cholestyramine treatment was observed. No changes were detected in serum concentrations of CML, usCRP or glycemic control, after treatment. The latter variables were not correlated with neurophthalmologic studies. DISCUSSION: In this preliminary study we did not observe changes in MFERG nor VEP after 6 g/day cholestyramine treatment, which did not induce lowering of CML levels. This could be attributed to the many limitations of a pilot study, such as a small sample size, short duration of treatment, reduced doses. However this design allowed to evaluate the patients´ tolerance to the drug and rule out adverse effects, in order to plan further studies using the necessary doses to obtain lowering of AGEs

Advanced glycation end-products (AGEs) accumulation in skin: relations with chronic kidney disease-mineral and bone disorder / Acúmulo dos produtos finais da glicação avançada (AGEs) na pele: relações com o distúrbio mineral e ósseo na doença renal crônica

Abstract Introduction: Chronic kidney disease (CKD) is associated with high morbidity and mortality rates, main causes related with cardiovascular disease (CVD) and bone mineral disorder (CKD-BMD). Uremic toxins, as advanced glycation end products (AGEs), are non-traditional cardiovascular risk factor and play a role on development of CKD-BMD in CKD. The measurement of skin autofluorescence (sAF) is a noninvasive method to assess the level of AGEs in tissue, validated in CKD patients. Objective: The aim of this study is analyze AGEs measured by sAF levels (AGEs-sAF) and its relations with CVD and BMD parameters in HD patients. Methods: Twenty prevalent HD patients (HD group) and healthy subjects (Control group, n = 24), performed biochemical tests and measurements of anthropometric parameters and AGEs-sAF. In addition, HD group performed measurement of intact parathormone (iPTH), transthoracic echocardiogram and radiographies of pelvis and hands for vascular calcification score. Results: AGEs-sAF levels are elevated both in HD and control subjects ranged according to the age, although higher at HD than control group. Single high-flux HD session does not affect AGEs-sAF levels. AGEs-sAF levels were not related to ventricular mass, interventricular septum or vascular calcification in HD group. AGEs-sAF levels were negatively associated with serum iPTH levels. Conclusion: Our study detected a negative correlation of AGEs-sAF with serum iPTH, suggesting a role of AGEs on the pathophysiology of bone disease in HD prevalent patients. The nature of this relation and the clinical application of this non-invasive methodology for evaluation AGEs deposition must be confirmed and clarified in future studies.

Resumo Introdução: A doença renal crônica (DRC) apresenta elevadas taxas de morbidade e mortalidade, sendo a doença cardiovascular (DCV) e o distúrbio mineral e ósseo da DRC (DMO-DRC) complicações frequentes. As toxinas urêmicas, dentre elas os produtos finais da glicação avançada (AGEs), são fatores de risco cardiovascular não tradicionais e se encontram envolvidas no desenvolvimento do DMO-DRC na DRC. A medida da autofluorescência da pele (sAF) é método não invasivo para quantificação do acúmulo tecidual de AGEs validado em pacientes portadores de DRC. Objetivos: O objetivo deste estudo é avaliar as relações entre os AGEs medidos por sAF (AGEs-AF) e parâmetros de DCV e DMO-DRC em pacientes em hemodiálise (HD). Métodos: 20 pacientes em HD (grupo HD) e 24 indivíduos hígidos (grupo controle) foram submetidos à análise bioquímica sérica, medidas antropométricas e de sAF. O grupo HD realizou medida de hormônio intacto da paratireoide (PTHi), ecocardiograma transtorácico e radiografias de pelve e mãos para pesquisa de calcificação vascular. Resultados: Os níveis de AGEs-sAF foram elevados para a idade nos grupos HD e controle, porém mais elevados no grupo HD. Sessão única de HD de alto-fluxo não afetou os níveis de AGEs-sAF. Os níveis teciduais de AGEs não se correlacionaram com massa ventricular, espessura de septo interventricular ou calcificação vascular no grupo HD. Os níveis de AGEs-sAF se correlacionaram negativamente com os níveis séricos de PTHi. Conclusão: Nosso estudo detectou correlação negativa entre os níveis de AGEs-sAF e os níveis séricos de PTHi, sugerindo que os AGEs estejam envolvidos na fiosiopatologia da doença óssea em pacientes em HD. A natureza desta relação e a aplicação clínica deste método não invasivo de avaliação do acúmulo tecidual de AGEs deve ser confirmada e elucidada por estudos futuros.

Serum Fluorescent Advanced Glycation End (F-AGE) products in gestational diabetes patients

ABSTRACT Objectives Advanced glycation end products (AGEs) are involved in the pathogenesis and complications of diabetes mellitus (DM). Gestational DM (GDM) is characterized by increased glycemia and oxidative stress, which are factors associated with high serum AGE concentrations. The aim of this study was to evaluate the utility of a serum fluorescence AGE (F-AGE) method as a screening tool for gestational diabetes. Subjects and methods Serum samples from 225 GDM patients and 217 healthy pregnant women (healthy controls) were diluted 50-fold in phosphate-buffered saline, and the AGEs were estimated by fluorometric analysis (λEx 350 nm/ λEm 440 nm). Results No significant (P > 0.05) differences in AGE concentrations, expressed in Arbitrary Units (UA/mL × 104), were observed in the women with GDM or in the healthy controls. Furthermore, F-AGE concentrations did not change significantly during the pregnancy (12-32 weeks of gestation). Only the GDM group had a positive correlation (r = 0.421; P < 0.001) between F-AGEs and serum creatinine concentrations. Conclusion It was not possible to distinguish women with gestational diabetes from the healthy controls on the basis of serum F-AGE concentrations.

Interaction between ascorbic acid and gallic acid in a model of fructose-mediated protein glycation and oxidation

Background: Dietary plant-based foods contain combinations of various bioactive compounds such as phytochemical compounds and vitamins. The combined effect of these vitamins and phytochemicals remains unknown, especially in the prevention of diabetes and its complications. The present study aimed to investigate the combined effect of ascorbic acid and gallic acid on fructose-induced protein glycation and oxidation. Results: Ascorbic acid (15 µg/mL) and gallic acid (0.1 µg/mL) reduced fructose-induced formation of advanced glycation end products (AGEs) in bovine serum albumin (BSA; 10 mg/mL) by 15.06% and 37.83%, respectively. The combination of ascorbic acid and gallic acid demonstrated additive inhibition on the formation of AGEs after 2 weeks of incubation. In addition, synergistic inhibition on the formation of amyloid cross-ß structure and protein carbonyl content in fructose-glycated BSA was observed. At the same concentration, the combination of ascorbic acid and gallic acid produced a significant additive effect on the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. Conclusion: Combining natural compounds such as ascorbic acid and gallic acid seems to be a promising strategy to prevent the formation of AGEs.

Inflamação renal, alterações metabólicas e oxidativas após 6 semanas de dieta de cafeteria em ratos / Renal inflammatory and oxidative and metabolic changes after 6 weeks of cafeteria diet in rats

Resumo Introdução: A obesidade é uma doença em que a inflamação está inteiramente envolvida e pode causar insuficiência renal. Objetivo: Avaliar a influência da exposição a curto prazo de uma dieta de cafeteria sobre a inflamação no tecido renal e a formação de produtos de glicação avançada (AGEs) no plasma de rato. Métodos: Ratos Wistar machos (10 semanas de idade, pesando 350 g) foram designados para receber dieta de ração comercial (C; n = 8 animais/grupo, 5% de energia a partir de gordura) ou dieta de cafeteria (CAF-D, n = 8 animais/grupo: 29% de energia de gordura) e de sacarose em água (300 g/L) de beber durante 6 semanas. Resultados: Índice de adiposidade em seis semanas foi maior no grupo CAF-D em comparação com C. O mesmo comportamento foi observado para os níveis plasmáticos de glicose, triglicerídeos, leptina, insulina e AGEs. A expressão do gene de IL-6 e TNF-α em tecido renal foi maior no grupo D-CAF e nenhuma diferença significativa no tecido adiposo. Não houve aumento destas citocinas no plasma ou rim. Houve uma diminuição significativa de adiponectina no grupo CAF-D. Conclusão: A exposição a curto prazo da CAF-D reflete alterações no metabolismo, aumento dos níveis plasmáticos de AGEs, o que pode refletir o aumento expressão de citocinas inflamatórias no rim.

Abstract Introduction: Obesity is a disease in which inflammation is directly involved and can lead to impaired renal function. Objective: To evaluate the influence of short term exposure to cafeteria diet on kidney tissue inflammation and advanced glycation end products (AGEs) in the rat plasma. Methods: Male Wistar rats (10 weeks of age, weighing 350 g) were assigned to receive commercial chow diet (C; n = 8 animals/group, 5% of energy from fat) or cafeteria diet (CAF-D, n = 8 animals/group: 29% energy fat) and sucrose in drinking water (300 g/L) for 6 weeks. Results: adiposity index at six weeks was higher in CAF-D group compared to C. The same behavior was observed for plasma levels of glucose, triglycerides, leptin, insulin and AGEs. The gene expression of IL-6 and TNF-α in renal tissue was higher in CAF-D group and no significant difference in adipose tissue. There was no increase of these cytokines in plasma and kidney or histologically. There was a significant decrease of adiponectin in the CAF-D group. Conclusion: The short exposure CAF-D reflects changes in metabolism, increased plasma levels of AGEs, which may reflect the increased expression of inflammatory cytokines in the kidney.