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1.
Exp Gerontol ; 117: 76-90, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30458224

RESUMO

Advanced glycation end products (AGEs) are formed in in vivo, and accumulate in tissues and body fluids during ageing. Endogenous AGE-modified proteins show altered structure and function, and may interact with receptor for AGEs (RAGE) resulting in production of reactive oxygen species, inflammatory, atherogenic and diabetogenic responses. AGEs are also formed in thermally processed foods. Studies in rodents document that dietary AGEs are partially absorbed into circulation, and accumulate in different tissues. Knowledge on the health effects of high dietary intake of AGEs is incomplete and contradictory. In this overview we discuss the data from experimental and clinical studies, either those supporting the assumption that restriction of dietary AGEs associated with health benefits, or data suggesting that dietary intake of AGEs associates with positive health outcomes. We polemicize whether the effects of exaggerated intake or restriction of highly thermally processed foods might be straightforward interpreted as the effects of AGEs-rich vs. AGEs-restricted diets. We also underline the lack of studies, and thus a poor knowledge, on the effects of different single chemically defined AGEs administration, concurrent intake of different dietary AGEs, of load with dietary AGEs corresponding to the habitual diet in humans, and on those of dietary AGEs in vulnerable populations, such as infants and particularly elderly.


Assuntos
Dieta , Proteínas Alimentares/farmacocinética , Produtos Finais de Glicação Avançada/farmacocinética , Animais , Disponibilidade Biológica , Proteínas Alimentares/administração & dosagem , Proteínas Alimentares/efeitos adversos , Proteínas Alimentares/análise , Fast Foods/análise , Análise de Alimentos/métodos , Produtos Finais de Glicação Avançada/administração & dosagem , Produtos Finais de Glicação Avançada/efeitos adversos , Produtos Finais de Glicação Avançada/análise , Humanos , Modelos Animais
2.
Medicine (Baltimore) ; 96(33): e7456, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28816938

RESUMO

The aim of the study was to elucidate the mechanism by which advanced glycation end products (AGEs) promote cell proliferation in liver cancer cells.We treated liver cancer HepG2 cells with 200 mg/L AGEs or bovine serum albumin (BSA) and assayed for cell viability, cell cycle, and apoptosis. We performed real-time PCR and Western blot analysis for RNA and protein levels of carbohydrate responsive element-binding protein (ChREBP) in AGEs- or BSA-treated HepG2 cells. We analyzed the level of reactive oxygen species (ROS) in HepG2 cells treated with AGEs or BSA.We found that increased S-phase cell percentage and decreased apoptosis contributed to AGEs-induced liver cancer cell proliferation. Real-time PCR and Western blot analysis showed that AGEs stimulated RNA and protein levels of ChREBP, a transcription factor promoting glycolysis and maintaining cell proliferation in liver cancer cells. Intriguingly, the level of ROS was higher in AGEs-treated liver cancer cells. Treating liver cancer cells with antioxidant N-acetyl cystein (NAC) partly blocked AGEs-induced ChREBP expression and cell proliferation.Our results suggest that the AGEs-ROS-ChREBP pathway plays a critical role in promoting ChREBP expression and liver cancer cell proliferation.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/biossíntese , Carcinoma Hepatocelular/metabolismo , Produtos Finais de Glicação Avançada/farmacocinética , Neoplasias Hepáticas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Acetilcisteína/farmacologia , Apoptose , Proliferação de Células , Sobrevivência Celular , Humanos , RNA Mensageiro/biossíntese , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição/metabolismo , Células Tumorais Cultivadas
3.
Biosci Rep ; 36(2)2016.
Artigo em Inglês | MEDLINE | ID: mdl-26893485

RESUMO

Advanced glycation end products (AGEs) have been confirmed to induce bone quality deterioration in diabetes mellitus (DM), and to associate with abnormal expression of miRNAs in DM patients or in vitro Recently, miRNAs have been recognized to mediate the onset or progression of DM. In the present study, we investigated the regulation on miR-223 level by AGE-BSA treatment in osteoblast-like MC3T3-E1 cells, with real-time quantitative PCR assay. And then we examined the inhibition of insulin-like growth factor 1 receptor (IGF-1R) expression by miR-223, via targeting of the 3' UTR of IGF-1R with real-time quantitative PCR, western blotting and luciferase reporter assay. Then we explored the regulation of miR-223 and IGF-1R levels, via the lentivirus-mediated miR-223 inhibition and IGF-1R overexpression in the AGE-BSA-induced apoptosis in MC3T3-E1 cells. It was demonstrated that AGE-BSA treatment with more than 100 µg/ml significantly up-regulated miR-223 level, whereas down-regulated IGF-1R level in MC3T3-E1 cells. And the up-regulated miR-223 down-regulated IGF-1R expression in both mRNA and protein levels, via targeting the 3' UTR of IGF-1R Moreover, though the AGE-BSA treatment promoted apoptosis in MC3T3-E1 cells, the IGF-1R overexpression or the miR-223 inhibition significantly attenuated the AGE-BSA-promoted apoptosis in MC3T3-E1 cells. In summary, our study recognized the promotion of miR-223 level by AGE-BSA treatment in osteoblast-like MC3T3-E1 cells. The promoted miR-223 targeted IGF-1R and mediated the AGE-BSA-induced apoptosis in MC3T3-E1 cells. It implies that miR-223 might be an effective therapeutic target to antagonize the AGE-induced damage to osteoblasts in DM.


Assuntos
Regiões 3' não Traduzidas , Apoptose/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Produtos Finais de Glicação Avançada/farmacocinética , MicroRNAs/metabolismo , Osteoblastos/metabolismo , Receptor IGF Tipo 1/biossíntese , Animais , Apoptose/genética , Linhagem Celular , Produtos Finais de Glicação Avançada/metabolismo , Camundongos , MicroRNAs/genética , Osteoblastos/citologia , Receptor IGF Tipo 1/genética
4.
Minerva Endocrinol ; 39(3): 167-74, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25068304

RESUMO

Obesity affects ovarian function, one of the main regulators of female fertility. Tissue levels of the proinflammatory advanced glycation end-products (AGEs) and their receptors (RAGE) are elevated in obesity. AGEs are key contributors to perturbations in the ovarian microenvironment. On this basis, the present review focuses on clinical and experimental studies supporting the role of AGE-RAGE system as a contributor to obesity-related ovarian dysfunction. Particular emphasis has been given to changes in AGEs, RAGE and the anti-inflammatory soluble receptor (sRAGE) levels in obesity state and following dietary interventions (high-fat diet and weight loss). Ovarian sensitivity, in particular granulosa cell function and oocyte meiosis, to the pro-inflammatory AGE-RAGE system as well as the relationship of follicular fluid AGEs and sRAGE to in vitro fertilization outcome are also discussed. Overall, obesity, with its alterations in the AGE-RAGE system, can disrupt the ovarian microenvironment potentially compromising oocyte competence and fertility. This review underscores a critical need to uncover the mechanistic actions of AGE-RAGE system in obesity-related ovarian dysfunction. Clinical and basic studies focusing on elucidating the patterns of accumulation and role of the AGE-RAGE system in human ovarian follicles are key steps in understanding their contribution to the health of human oocytes and embryos.


Assuntos
Produtos Finais de Glicação Avançada/fisiologia , Infertilidade Feminina/etiologia , Obesidade/complicações , Ovário/fisiopatologia , Anovulação/etiologia , Anovulação/fisiopatologia , Hormônio Antimülleriano/sangue , Microambiente Celular , Dieta Ocidental/efeitos adversos , Feminino , Fertilização in vitro , Líquido Folicular/metabolismo , Produtos Finais de Glicação Avançada/metabolismo , Produtos Finais de Glicação Avançada/farmacocinética , Humanos , Infertilidade Feminina/metabolismo , Infertilidade Feminina/fisiopatologia , Inflamação , Obesidade/metabolismo , Obesidade/fisiopatologia , Estresse Oxidativo , Gravidez , Resultado da Gravidez , Receptor para Produtos Finais de Glicação Avançada/fisiologia , Solubilidade
5.
Exp Gerontol ; 48(6): 549-56, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23531498

RESUMO

UNLABELLED: Aging is characterized by progressive loss of metabolic and biochemical functions and accumulation of metabolic by-products, including advanced glycation end products (AGEs), which are observed in several pathological conditions. A number of waste macromolecules, including AGEs are taken up from the circulation by endocytosis mainly into liver sinusoidal endothelial cells (LSECs) and Kupffer cells (KCs). However, AGEs still accumulate in different tissues with aging, despite the presence of this clearance mechanism. The aim of the present study was to determine whether the efficiency of LSECs and KCs for disposal of AGEs changes through aging. RESULTS: After intravenous administration of (14)C-AGE-albumin in pre-pubertal, young adult, middle aged and old mice, more than 90% of total recovered (14)C-AGE was liver associated, irrespective of age. LSECs and KCs represented the main site of uptake. A fraction of the (14)C-AGE degradation products ((14)C-AGE-DPs) was stored for months in the lysosomes of these cells after uptake. The overall rate of elimination of (14)C-AGE-DPs from the liver was markedly faster in pre-pubertal than in all post-pubertal age groups. The ability to eliminate (14)C-AGE-DPs decreased to similar extents after puberty in LSECs and KCs. A rapid early removal phase was characteristic for all age groups except the old group, where this phase was absent. CONCLUSIONS: Removal of AGE-DPs from the liver scavenger cells is a very slow process that changes with age. The ability of these cells to dispose of AGEs declines after puberty. Decreased AGE removal efficiency early in life may lead to AGE accumulation.


Assuntos
Envelhecimento/fisiologia , Endocitose/fisiologia , Produtos Finais de Glicação Avançada/farmacocinética , Fígado/metabolismo , Animais , Radioisótopos de Carbono , Endocitose/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Produtos Finais de Glicação Avançada/metabolismo , Injeções Intravenosas , Células de Kupffer/efeitos dos fármacos , Células de Kupffer/metabolismo , Fígado/irrigação sanguínea , Fígado/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Maturidade Sexual
6.
Clinics (Sao Paulo) ; 65(6): 635-43, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20613941

RESUMO

Increased intestinal permeability is a likely cause of various pathologies, such as allergies and metabolic or even cardiovascular disturbances. Intestinal permeability is found in many severe clinical situations and in common disorders such as irritable bowel syndrome. In these conditions, substances that are normally unable to cross the epithelial barrier gain access to the systemic circulation. To illustrate the potential harmfulness of leaky gut, we present an argument based on examples linked to protein or lipid glycation induced by modern food processing. Increased intestinal permeability should be largely improved by dietary addition of compounds, such as glutamine or curcumin, which both have the mechanistic potential to inhibit the inflammation and oxidative stress linked to tight junction opening. This brief review aims to increase physician awareness of this common, albeit largely unrecognized, pathology, which may be easily prevented or improved by means of simple nutritional changes.


Assuntos
Dieta/efeitos adversos , Suplementos Nutricionais/efeitos adversos , Manipulação de Alimentos , Hipersensibilidade Alimentar/etiologia , Motilidade Gastrointestinal/fisiologia , Absorção Intestinal/fisiologia , Curcumina/uso terapêutico , Glutamina/uso terapêutico , Produtos Finais de Glicação Avançada/efeitos adversos , Produtos Finais de Glicação Avançada/farmacocinética , Humanos , Inflamação/metabolismo , Síndrome Metabólica/etiologia , Permeabilidade
7.
Blood Purif ; 29(2): 130-6, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20093818

RESUMO

Part of the uremic retention solutes are generated in the intestine, but this option is rarely discussed in the literature. In this publication, we describe consecutively the role of the intestine in generating uremic retention solutes, the pathophysiological importance of the generated solutes and therapeutic options that are inspired by this knowledge. Apart from its role as a route via which uremic toxins or their precursors enter the body, the intestine also acts as an active player by presenting more precursors for fermentation due to disturbances in assimilation caused by uremia, followed by alterations in further processing related to changes in the composition of the fermenting flora. Many of the toxins generated or introduced into the body via the intestine (advanced glycation end products, indoles, phenols) play an active role in vascular damage. Intestinal therapeutic interventions that could help decrease solute concentration are restriction of dietary intake, however at the expense of increasing the risk of malnutrition, rerouting of intestinal metabolism by administration of prebiotics or probiotics and/ or the administration of active sorbents such as AST-120 (Kremezin).


Assuntos
Intestinos/fisiopatologia , Toxinas Biológicas/metabolismo , Uremia/fisiopatologia , Bactérias/metabolismo , Biotransformação , Carbono/uso terapêutico , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/fisiopatologia , Doenças Cardiovasculares/prevenção & controle , Digestão , Fermentação , Conteúdo Gastrointestinal , Taxa de Filtração Glomerular , Produtos Finais de Glicação Avançada/metabolismo , Produtos Finais de Glicação Avançada/farmacocinética , Humanos , Indóis/metabolismo , Indóis/farmacocinética , Absorção Intestinal , Mucosa Intestinal/metabolismo , Intestinos/microbiologia , Óxidos/uso terapêutico , Diálise Peritoneal , Fenóis/metabolismo , Fenóis/farmacocinética , Prebióticos , Probióticos , Diálise Renal , Uremia/sangue , Uremia/complicações , Uremia/terapia
8.
Pathol Biol (Paris) ; 58(3): 200-6, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19896300

RESUMO

The questions we were asked by Dr Edeas, president of the French Society of Antioxidants to discuss in this introductory lecture are the following: (a) the metabolism of glycation; (b) what are its consequences at the cellular level, and (c) their effect on health. As a recent and vast literature is available on these subjects, in the following we present a short survey of some basic data on the proposed subjects, insisting on our own experiments on the cytotoxicity of Maillard products and on a new approach to prevent the aggravation and acceleration of age-related diseases, essentially diabetes type II and its consequences on the cardiovascular system.


Assuntos
Alimentos/efeitos adversos , Produtos Finais de Glicação Avançada/efeitos adversos , Reação de Maillard , Envelhecimento/metabolismo , Animais , Arteriosclerose/metabolismo , Arteriosclerose/prevenção & controle , Química Orgânica/história , Complicações do Diabetes/metabolismo , Complicações do Diabetes/prevenção & controle , Diabetes Mellitus/metabolismo , Fibroblastos/efeitos dos fármacos , Manipulação de Alimentos , França , Radicais Livres/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Produtos Finais de Glicação Avançada/metabolismo , Produtos Finais de Glicação Avançada/farmacocinética , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Estresse Oxidativo , Ratos , Espécies Reativas de Oxigênio/metabolismo , Ramnose/metabolismo , Ramnose/uso terapêutico
9.
J Card Fail ; 14(7): 596-602, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18722326

RESUMO

BACKGROUND: Diastolic dysfunction is a frequent cause of heart failure, particularly in dialysis patients. Advanced glycation end-products (AGEs) are increased in dialysis patients and are suggested to play a role in the development of diastolic dysfunction. The aim of our study was to assess whether AGE accumulation in dialysis patients is related to the presence of diastolic dysfunction. METHODS AND RESULTS: Data were analyzed from 43 dialysis patients, age 58 +/- 15 years, of whom 65% were male. Diastolic function was assessed using tissue velocity imaging (TVI) on echocardiography. Tissue AGE accumulation was measured using a validated skin-autofluorescence (skin-AF) reader. Plasma N(epsilon)-(carboxymethyl)lysine (CML) and N(epsilon)-(carboxyethyl)lysine (CEL) were measured by stable-isotope-dilution tandem mass spectrometry. Plasma pentosidine was measured by high-performance liquid chromatography. Skin-AF correlated with mean E' (r = -0.51, P < .001), E/A ratio (r = -0.39, P = .014), and E/E' (r = 0.38, P = .019). Plasma AGEs were not significantly associated with diastolic function. Multivariable linear regression analysis revealed that 54% of the variance of average E' was explained by age (P = .007), dialysis type (P = 0.016), and skin-AF (P = .013). CONCLUSIONS: Tissue AGEs measured as skin-AF, but not plasma AGE levels, were related to diastolic function in dialysis patients. Although this may support the concept that tissue AGEs explain part of the increased prevalence of diastolic dysfunction in these patients, the ambiguous relation between plasma and tissue AGEs needs further exploring.


Assuntos
Produtos Finais de Glicação Avançada/análise , Insuficiência Cardíaca Diastólica/etiologia , Diálise Renal , Pele/metabolismo , Disfunção Ventricular/etiologia , Fatores Etários , Arginina/análogos & derivados , Arginina/sangue , Arginina/farmacocinética , Volume Cardíaco/fisiologia , Cromatografia Líquida de Alta Pressão , Estudos Transversais , Ecocardiografia , Ecocardiografia Doppler , Ecocardiografia Doppler em Cores , Feminino , Fluorescência , Produtos Finais de Glicação Avançada/sangue , Produtos Finais de Glicação Avançada/farmacocinética , Insuficiência Cardíaca Diastólica/fisiopatologia , Humanos , Lisina/análogos & derivados , Lisina/sangue , Lisina/farmacocinética , Masculino , Pessoa de Meia-Idade , Contração Miocárdica/fisiologia , Diálise Renal/classificação , Fatores de Risco , Fatores Sexuais , Pele/fisiopatologia , Volume Sistólico/fisiologia , Espectrometria de Massas em Tandem , Disfunção Ventricular/fisiopatologia , Função Ventricular/fisiologia , Pressão Ventricular/fisiologia
10.
Mol Nutr Food Res ; 51(9): 1085-90, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17854004

RESUMO

In vivo, advanced glycation endproducts (AGEs) are linked to various diseases, particularly those associated with diabetes. AGEs are also formed when many foods are thermally processed. The extent to which dietary AGEs are absorbed by the gastrointestinal (GI) tract and their possible role in the onset and promotion of disease are currently of considerable interest. This paper reviews information that supports the argument that dietary AGEs are not a risk to human health.


Assuntos
Dieta , Produtos Finais de Glicação Avançada/efeitos adversos , Disponibilidade Biológica , Produtos Finais de Glicação Avançada/administração & dosagem , Produtos Finais de Glicação Avançada/farmacocinética , Humanos , Lisina/análogos & derivados , Lisina/química , Reação de Maillard , Fatores de Risco
11.
Mol Nutr Food Res ; 50(12): 1140-9, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17131455

RESUMO

Advanced glycation end products (AGEs) are generated in the late stages of Maillard reaction in foods and biological systems. These products are mostly formed by the reactions of reducing sugar or degradation products of carbohydrates, lipids, and ascorbic acid. AGEs exist in high concentration in foods, but in relatively low concentrations in most of the biological systems. Recently, some AGEs have been reported to be toxic, and were proposed to be causative factors for various kinds of diseases, especially diabetes and kidney disorder, through the association with receptor of AGE (RAGE). It has also been reported that food-derived AGEs (food-AGEs) may not be a causative factor for pro-oxidation. However, the relationship of food-AGEs and biological-derived AGEs (biological-AGEs) is not clear. In this review, the following issues are discussed: the formation of AGEs in foods and biological systems; identification of the main AGEs in foods and biological systems; absorption of food-AGEs; the effects of AGEs in vivo; relationship between food-AGEs and biological-AGEs; possible defense mechanism against AGEs in vivo and finally, the problems to be solved concerning the toxicity of AGEs.


Assuntos
Alimentos , Produtos Finais de Glicação Avançada/química , Produtos Finais de Glicação Avançada/toxicidade , Reação de Maillard , Absorção , Animais , Complicações do Diabetes/etiologia , Carboidratos da Dieta/análise , Gorduras na Dieta/análise , Proteínas Alimentares/análise , Produtos Finais de Glicação Avançada/biossíntese , Produtos Finais de Glicação Avançada/farmacocinética , Humanos , Carne/análise
12.
J Biochem ; 139(5): 821-9, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16751589

RESUMO

Cellular interactions with advanced glycation end products (AGE)-modified proteins are known to induce several biological responses, not only endocytic uptake and degradation, but also the induction of cytokines and growth factors, combined responses that may be linked to the development of diabetic vascular complications. In this study we demonstrate that A549 cells, a human pulmonary epithelial cell line, possess a specific binding site for AGE-modified bovine serum albumin (AGE-BSA) (K(d) = 27.8 nM), and additionally for EN-RAGE (extracellular newly identified RAGE binding protein) (K(d) = 118 nM). Western blot and RT-PCR analysis showed that RAGE (receptor for AGE) is highly expressed on A549 cells, while the expression of other known AGE-receptors such as galectin-3 and SR-A (class A scavenger receptor), are below the level of detection. The binding of (125)I-AGE-BSA to these cells is inhibited by unlabeled AGE-BSA, but not by EN-RAGE. In contrast, the binding of (125)I-EN-RAGE is significantly inhibited by unlabeled EN-RAGE and soluble RAGE, but not by AGE-BSA. Our results indicate that A549 cells possess at least two binding sites, one specific for EN-RAGE and the other specific for AGE-BSA. The latter receptor on A549 cells is distinct from the scavenger receptor family and RAGE.


Assuntos
Células Epiteliais/metabolismo , Produtos Finais de Glicação Avançada/metabolismo , Receptores Imunológicos/classificação , Animais , Bovinos , Células Cultivadas , Produtos Finais de Glicação Avançada/farmacocinética , Humanos , Pulmão/metabolismo , Ligação Proteica , Receptor para Produtos Finais de Glicação Avançada , Receptores Imunológicos/agonistas , Receptores Depuradores/agonistas , Receptores Depuradores/classificação , Receptores Depuradores/metabolismo , Proteínas Recombinantes/metabolismo , Soroalbumina Bovina/metabolismo , Soroalbumina Bovina/farmacocinética , Transdução de Sinais , Especificidade por Substrato
13.
Metabolism ; 55(4): 494-500, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16546480

RESUMO

Exogenous advanced glycation endproducts (AGEs, known atherogenic molecules) abundant in everyday precooked, rich in fat, overheated meals can possibly contribute to the increased risk for diabetes and cardiovascular disease in women with polycystic ovary syndrome (PCOS). The aim of the present study was to investigate the effect of a lipase inhibitor on absorbed food glycotoxins in healthy women and those with PCOS. A 2-day protocol was followed. In the first day, a meal rich in AGE was provided, which on the second day was followed by two 120-mg capsules of lipase inhibitor, orlistat. Serum AGE levels were evaluated at baseline (0 hours), and at 3 and 5 hours postmeal during the study. Thirty-six women were studied, 15 controls (mean age, 28.80 +/- 5.47 years; body mass index, 25.85 +/- 6.73 kg/m(2)) and 21 with PCOS (mean age, 25.29 +/- 5.06 years; body mass index, 30.40 +/- 7.51 kg/m(2)) (University Hospital, Athens, Greece, institutional practice). Serum AGE levels, on day 1, were significantly increased both in the control group and in the PCOS group as compared with basal values (control group, 14.1%; PCOS group, 6.0%; P < .001). The corresponding rise was significantly lower on day 2 when the same meal was combined with orlistat (control group, 4.1%; PCOS group, 2.0%; P < .01). A limitation of the study is that it is a nonplacebo, nonrandomized therapeutic trial where each subject is considered as its own control. In conclusion, this study demonstrated the beneficial effect of orlistat on the absorption of food glycotoxins.


Assuntos
Dieta , Inibidores Enzimáticos/farmacologia , Produtos Finais de Glicação Avançada/administração & dosagem , Produtos Finais de Glicação Avançada/farmacocinética , Lactonas/farmacologia , Síndrome do Ovário Policístico/metabolismo , Absorção/efeitos dos fármacos , Adulto , Androgênios/sangue , Estudos de Casos e Controles , Feminino , Produtos Finais de Glicação Avançada/sangue , Humanos , Lipase/antagonistas & inibidores , Orlistate , Síndrome do Ovário Policístico/sangue , Testosterona/sangue
14.
Transplant Proc ; 37(10): 4266-72, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16387094

RESUMO

BACKGROUND: Advanced glycation end products (AGEs) accumulate in lesions of arteriosclerosis, Alzheimer's disease, rheumatoid arthritis, diabetic retinopathy, and diabetic nephropathy. Among AGEs, chemical quantification and immunohistologic methods for pentosidine have been established. Free pentosidine-eliminated by renal excretion- is mainly affected by renal function. In this study, we measured concentrations of plasma free and total pentosidine and immunohistologically investigated kidney graft biopsy specimens in patients after renal transplantation to investigate the renal function, plasma free and total pentosidine, and its relationship with deposition in the renal tissue. PATIENTS AND METHODS: In 28 patients who underwent renal transplantation from 1996 to 2003, we measured the time course of plasma concentrations of free pentosidine, total pentosidine, and serum creatinine starting right after renal transplantation. Thirty-four graft biopsy specimens were immunohistologically investigated using anti-pentosidine antibody. Plasma free and total pentosidine, and serum creatinine were measured at the same time. RESULTS: Plasma free and total pentosidine were positively correlated with serum creatinine. Plasma free pentosidine and serum creatinine reached nadir values on day 34.2 +/- 14.2, when the blood concentrations were 5.1 +/- 1.6 pmol/mL and 1.7 +/- 0.7 mg/dL, respectively. Plasma total pentosidine reached a nadir on day 116.5 +/- 39.7 when the plasma concentration was 4.0 +/- 1.5 pmol/mg. We correlated the time required to reach the nadir of plasma free and total pentosidine concentrations. However, neither the concentration of plasma free nor plasma total pentosidine at nadir correlated with serum creatinine. The intensity of immunostaining with anti-pentosidine antibody in proximal tubular cells was graded as weakly positive, positive, or strongly positive. Significant differences were obtained among plasma free pentosidine values between the weakly positive and strongly positive groups. CONCLUSIONS: Renal transplantation improves renal function and decreases renal excretion of free pentosidine. Accordingly, total pentosidine also decreases. However, the concentrations of plasma free and total pentosidine at nadir varied among individuals; the blood concentrations were not determined by renal function alone. It was suggested that deposition of pentosidine in proximal tubular cells was more severe among patients with higher plasma free pentosidine and serum creatinine values.


Assuntos
Arginina/análogos & derivados , Transplante de Rim/fisiologia , Rim/fisiologia , Lisina/análogos & derivados , Adulto , Arginina/sangue , Arginina/farmacocinética , Cadáver , Creatinina/sangue , Produtos Finais de Glicação Avançada/sangue , Produtos Finais de Glicação Avançada/farmacocinética , Humanos , Testes de Função Renal , Doadores Vivos , Lisina/sangue , Lisina/farmacocinética , Pessoa de Meia-Idade , Estudos Retrospectivos , Doadores de Tecidos
15.
Kidney Int Suppl ; (84): S145-7, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12694332

RESUMO

The so-called Maillard reaction, or nonenzymatic glycation between proteins and carbohydrates, is of particular importance for the flavor, color, and shelf life of food. Despite the great variety of possible AGEs, which can be formed during heating processes, only a few have unequivocally been identified and quantified in foods. From the quantitative point of view, the amount of AGEs ingested with a conventional diet is much higher than the total amount of AGEs in the plasma and tissue. To date, however, only preliminary studies concerning digestion, resorption, and elimination of AGE-modified food proteins can be found in the literature, indicating that for patients with impaired kidney function, dietary AGEs might contribute significantly to the total AGE load of the body. To date, however, no conclusive answers or recommendations can be given regarding a possible role of AGEs as uremic toxins in general, and of dietary AGEs in particular.


Assuntos
Alimentos , Produtos Finais de Glicação Avançada/farmacocinética , Uremia/metabolismo , Conservação de Alimentos , Produtos Finais de Glicação Avançada/química , Temperatura Alta , Humanos
16.
J Am Soc Nephrol ; 14(5): 1123-31, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12707383

RESUMO

Advanced glycation end products (AGE) are filtered by glomeruli and reabsorbed and metabolized by proximal tubule cells (PTC). In renal failure, decreased renal AGE metabolism likely accounts for the accumulation in serum that is related to uremic complications. In diabetes, AGE generation is increased, and the handling mechanisms in PTC are likely associated with the pathogenesis of tubulointerstitial injury. It is therefore important to clarify the mechanisms of the AGE metabolism to develop a strategy for removing AGE in uremia and to elucidate the pathogenesis of diabetic nephropathy. To this end, this study focused on the molecular analysis of megalin, a multi-ligand endocytic receptor, in PTC. AGE uptake analysis was performed using the rat yolk sac-derived L2 cell line system established for the analysis of megalin's endocytic functions. The cells mediated specific internalization and degradation of AGE, which were significantly blocked by anti-megalin IgG, indicating that megalin is involved in the cellular processes. However, cell surface AGE-binding assays and ligand blot analysis revealed no evidence that megalin is a direct AGE receptor. Affinity chromatography and ligand blot analysis originally revealed that 200-kD and 400-kD proteins in the cells bind to AGE and the 200-kD protein to megalin in a Ca(2+)-dependent manner. The binding of megalin with the 200-kD protein was suppressed by receptor-associated protein (RAP), a ligand for megalin. In conclusion, megalin functions for endocytosis of AGE via an indirect mechanism. L2 cells express novel AGE-binding proteins, one of which may interact with megalin.


Assuntos
Proteínas de Transporte/metabolismo , Endocitose/fisiologia , Produtos Finais de Glicação Avançada/farmacocinética , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Animais , Cálcio/metabolismo , Proteínas de Transporte/química , Tumor do Seio Endodérmico , Radioisótopos do Iodo , Peso Molecular , Ligação Proteica/fisiologia , Coelhos , Ratos , Receptores de Superfície Celular/metabolismo , Células Tumorais Cultivadas
17.
J Am Soc Nephrol ; 14(3): 728-31, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12595509

RESUMO

Advanced glycation endproduct (AGE) levels are elevated in renal failure patients and may contribute to the excessive cardiovascular disease in this population. Diet-derived AGE are major contributors to the total body AGE pool. It was postulated that a reduction in dietary AGE intake might impact on the high circulating AGE levels in renal failure patients. Twenty-six nondiabetic renal failure patients on maintenance peritoneal dialysis were randomized to either a high or a low AGE diet for 4 wk. Three-day dietary records, fasting blood, 24-h urine, and dialysis fluid collections were obtained at baseline and end of study. AGE levels were determined by ELISA for N(epsilon)-carboxymethyl-lysine (CML) and methylglyoxal-derivatives (MG). Eighteen patients completed the study. Low dietary AGE intake decreased serum CML (34%; P < 0.002), serum MG (35%; P < 0.008), CML-LDL (28%; P < 0.011), CML-apoB (25%; P < 0.028), dialysate CML (39%; P < 0.03), and dialysate MG output (40%; P < 0.04). High dietary AGE intake increased serum CML (29%; P < 0.028), serum MG (26%; P < 0.09), CML-LDL (50%; P < 0.011), CML-apoB (67%; P < 0.028), and dialysate CML output (27%; P < 0.01). Serum AGE correlated with BUN (r = 0.6, P < 0.002 for CML; r = 0.4, P < 0.05 for MG), serum creatinine (r = 0.76, P < 0.05 for CML; r = 0.55, P < 0.004 for MG), total protein (r = 0.4, P < 0.05 for CML; r = 0.4, P < 0.05 for MG), albumin (r = 0.4, P < 0.02 for CML; r = 0.4, P < 0.05 for MG), and phosphorus (r = 0.5, P < 0.006 for CML; r = 0.5, P < 0.01 for MG). It is concluded that dietary glycotoxins contribute significantly to the elevated AGE levels in renal failure patients. Moreover, dietary restriction of AGE is an effective and feasible method to reduce excess toxic AGE and possibly cardiovascular associated mortality.


Assuntos
Produtos Finais de Glicação Avançada/efeitos adversos , Produtos Finais de Glicação Avançada/farmacocinética , Falência Renal Crônica/dietoterapia , Falência Renal Crônica/metabolismo , Adulto , Dieta , Humanos , Diálise Peritoneal , Análise de Regressão
18.
FEBS Lett ; 537(1-3): 85-90, 2003 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-12606036

RESUMO

Interaction of advanced glycation end products (AGE) with AGE receptors induces several cellular phenomena potentially relating to diabetic complications. We here show that AGE-modified bovine serum albumin (BSA) is endocytosed by adipocytes via CD36. Upon differentiation, 3T3-L1 and human subcutaneous adipose cells showed marked increases in endocytic uptake and subsequent degradation of [(125)I]AGE-BSA, which were inhibited effectively by the anti-CD36 antibody. Ligand specificity of CD36 for modified BSAs was compared with that of LOX-1 and scavenger receptor class A. Effect of fucoidan on [(125)I]AGE-BSA binding showed a sharp contrast to that on [(125)I]-oxidized low density lipoprotein. These results implicate that CD36-mediated interaction of AGE-modified proteins with adipocytes might play a pathological role in obesity or insulin-resistance.


Assuntos
Adipócitos/fisiologia , Antígenos CD/fisiologia , Antígenos CD36/fisiologia , Endocitose/fisiologia , Produtos Finais de Glicação Avançada/farmacocinética , 1-Metil-3-Isobutilxantina/farmacologia , Células 3T3 , Animais , Anticorpos/farmacologia , Antígenos CD/imunologia , Transporte Biológico , Antígenos CD36/imunologia , Dexametasona/farmacologia , Humanos , Camundongos , Soroalbumina Bovina/farmacocinética , Pele
19.
J Biol Chem ; 278(15): 12613-7, 2003 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-12473645

RESUMO

Advanced glycation end products (AGEs) are nonenzymatically glycosylated proteins, which accumulate in vascular tissues in aging and diabetes. Receptors for AGEs include scavenger receptors, which recognize acetylated low density lipoproteins (Ac-LDL) such as scavenger receptor class AI/AII (SR-A), cell surface glycoprotein CD36, scavenger receptor class B type I (SR-BI), and lectin-like oxidized low density lipoprotein receptor-1. The broad ligand repertoire of these receptors as well as the diversity of the receptors for AGEs have prompted us to examine whether AGEs are also recognized by the novel scavenger receptors, which we have recently isolated from a cDNA library prepared from human umbilical vein endothelial cells, such as the scavenger receptor expressed by endothelial cells-I (SREC-I); the fasciclin EGF-like, laminin-type EGF-like, and link domain-containing scavenger receptor-1 (FEEL-1); and its paralogous protein, FEEL-2. At 4 degrees C, (125)I-AGE-bovine serum albumin (BSA) exhibited high affinity specific binding to Chinese hamster ovary (CHO) cells overexpressing FEEL-1 (CHO-FEEL-1) and FEEL-2 (CHO-FEEL-2) with K(d) of 2.55 and 1.68 microg/ml, respectively, but not to CHO cells expressing SREC (CHO-SREC) and parent CHO cells. At 37 degrees C, (125)I-AGE-BSA was taken up and degraded by CHO-FEEL-1 and CHO-FEEL-2 cells but not by CHO-SREC and parent CHO cells. Thus, the ability to bind Ac-LDL is not necessarily a prerequisite to bind AGEs. The (125)I-AGE-BSA binding to CHO-FEEL-1 and CHO-FEEL-2 cells was effectively inhibited by Ac-LDL and polyanionic SR-A inhibitors such as fucoidan, polyinosinic acids, and dextran sulfate but not by native LDL, oxidized LDL, or HDL. FEEL-1, which is expressed by the liver and vascular tissues, may recognize AGEs, thereby contributing to the development of diabetic vascular complications and atherosclerosis.


Assuntos
Moléculas de Adesão Celular Neuronais/metabolismo , Endocitose/fisiologia , Receptores Imunológicos/metabolismo , Idoso , Animais , Sítios de Ligação , Ligação Competitiva , Transporte Biológico , Células CHO , Células Cultivadas , Cricetinae , Endotélio Vascular , Produtos Finais de Glicação Avançada/metabolismo , Produtos Finais de Glicação Avançada/farmacocinética , Humanos , Cinética , Proteínas de Membrana/metabolismo , Camundongos , Receptor para Produtos Finais de Glicação Avançada , Receptores de Retorno de Linfócitos , Proteínas Recombinantes/metabolismo , Soroalbumina Bovina/farmacocinética , Transfecção , Veias Umbilicais
20.
Med Hypotheses ; 58(4): 276-8, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12027519

RESUMO

Although there is much evidence supporting a prion contribution in the pathogenesis of transmissible spongiform encephalopathies, a novel point of view as to the induction of the diseases can be proposed. It is hypothesized that neurodegenerative diseases, such as scrapie in sheep and goats and bovine spongiform encephalopathy in cattle (BSE), originate from the consumption of glycated proteins contained in their feed. These components are obtained during a high-temperature glycation process.


Assuntos
Ração Animal/efeitos adversos , Proteínas Alimentares/efeitos adversos , Encefalopatia Espongiforme Bovina/etiologia , Produtos Finais de Glicação Avançada/efeitos adversos , Glicoproteínas/efeitos adversos , Ração Animal/análise , Animais , Bovinos , Proteínas Alimentares/farmacocinética , Produtos Finais de Glicação Avançada/farmacocinética , Glicoproteínas/farmacocinética , Reação de Maillard , Receptor para Produtos Finais de Glicação Avançada , Receptores Imunológicos/metabolismo , Rúmen/metabolismo
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