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BACKGROUND: Preeclampsia is a multifaceted syndrome that includes maternal vascular dysfunction. We hypothesize that increased placental glycolysis and hypoxia in preeclampsia lead to increased levels of methylglyoxal (MGO), consequently causing vascular dysfunction. METHODS: Plasma samples and placentas were collected from uncomplicated and preeclampsia pregnancies. Uncomplicated placentas and trophoblast cells (BeWo) were exposed to hypoxia. The reactive dicarbonyl MGO and advanced glycation end products (Nε-(carboxymethyl)lysine [CML], Nε-(carboxyethyl)lysine [CEL], and MGO-derived hydroimidazolone [MG-H]) were quantified using liquid chromatography-tandem mass spectrometry. The activity of GLO1 (glyoxalase-1), that is, the enzyme detoxifying MGO, was measured. The impact of MGO on vascular function was evaluated using wire/pressure myography. The therapeutic potential of the MGO-quencher quercetin and mitochondrial-specific antioxidant mitoquinone mesylate (MitoQ) was explored. RESULTS: MGO, CML, CEL, and MG-H2 levels were elevated in preeclampsia-placentas (+36%, +36%, +25%, and +22%, respectively). Reduced GLO1 activity was observed in preeclampsia-placentas (-12%) and hypoxia-exposed placentas (-16%). Hypoxia-induced MGO accumulation in placentas was mitigated by the MGO-quencher quercetin. Trophoblast cells were identified as the primary source of MGO. Reduced GLO1 activity was also observed in hypoxia-exposed BeWo cells (-26%). Maternal plasma concentrations of CML and the MGO-derived MG-H1 increased as early as 12 weeks of gestation (+16% and +17%, respectively). MGO impaired endothelial barrier function, an effect mitigated by MitoQ, and heightened vascular responsiveness to thromboxane A2. CONCLUSIONS: This study reveals the accumulation of placental MGO in preeclampsia and upon exposure to hypoxia, demonstrates how MGO can contribute to vascular impairment, and highlights plasma CML and MG-H1 levels as promising early biomarkers for preeclampsia.
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Biomarcadores , Placenta , Pré-Eclâmpsia , Aldeído Pirúvico , Pré-Eclâmpsia/metabolismo , Pré-Eclâmpsia/fisiopatologia , Pré-Eclâmpsia/sangue , Humanos , Feminino , Aldeído Pirúvico/metabolismo , Aldeído Pirúvico/sangue , Gravidez , Placenta/metabolismo , Biomarcadores/metabolismo , Biomarcadores/sangue , Adulto , Produtos Finais de Glicação Avançada/metabolismo , Trofoblastos/metabolismo , Lactoilglutationa Liase/metabolismoRESUMO
Reactive α-dicarbonyls (α-DCs), such as methylglyoxal (MGO), glyoxal (GO), and 3-deoxyglucosone (3-DG), are potent precursors in the formation of advanced glycation end products (AGEs). In particular, MGO and MGO-derived AGEs are thought to be involved in the development of vascular complications in diabetes. Experimental studies showed that citrus and pomegranate polyphenols can scavenge α-DCs. Therefore, the aim of this study was to evaluate the effect of a citrus and pomegranate complex (CPC) on the α-DCs plasma levels in a double-blind, placebo-controlled cross-over trial, where thirty-six elderly subjects were enrolled. They received either 500 mg of Citrus sinensis peel extract and 200 mg of Punica granatum concentrate in CPC capsules or placebo capsules for 4 weeks, with a 4-week washout period in between. For the determination of α-DCs concentrations, liquid chromatography tandem mass spectrometry was used. Following four weeks of CPC supplementation, plasma levels of MGO decreased by 9.8% (-18.7 nmol/L; 95% CI: -36.7, -0.7 nmol/L; p = 0.042). Our findings suggest that CPC supplementation may represent a promising strategy for mitigating the conditions associated with MGO involvement. This study was registered on clinicaltrials.gov as NCT03781999.
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Citrus , Punica granatum , Idoso , Humanos , Cápsulas , Produtos Finais de Glicação Avançada , Óxido de Magnésio , Aldeído PirúvicoRESUMO
Background and objective: Previous experimental studies have shown that fructose interacts with glucose metabolism by increasing hepatic glucose uptake. However, human studies investigating the effects of small ('catalytic') amounts of fructose, added to an oral glucose load, on plasma glucose levels remain inconclusive. The aim of this study, therefore, was to repeat and extend these previous studies by examining the plasma glucose response during a 75 g oral glucose tolerance test (OGTT) with the addition of different doses of fructose. Methods: Healthy adults (n = 13) received an OGTT without addition of fructose and OGTTs with addition of different doses of fructose (1, 2, 5, 7.5 and 15 g) in a random order, on six separate occasions. Plasma glucose levels were measured every 15 min for 120 min during the study. Findings: The plasma glucose incremental area under the curve (iAUC) of the OGTT without addition of fructose was not significantly different from any OGTT with fructose (p ≥ 0.2 for all fructose doses). Similar results were observed when these data were clustered with data from a similar, previous study (pooled mean difference: 10.6; 95%CI: 45.0; 23.8 for plasma glucose iAUC of the OGTT without addition of fructose versus an OGTT with 5 g fructose; fixed-effect meta-analysis, n = 38). Of interest, serum fructose increased from 4.8 µmol/L (interquartile range: 4.1-5.9) at baseline to 5.3 µmol/L (interquartile range: 4.8-7.5) at T = 60 min during an OGTT without addition of fructose (p = 0.002). Conclusion: Low doses of fructose added to an OGTT do not affect plasma glucose levels in healthy adults. The role of endogenous fructose production, as a potential explanation of these null-findings, deserves further investigation.
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The dicarbonyl compound methylglyoxal (MGO) is a major precursor in the formation of advanced glycation endproducts (AGEs). MGO and AGEs are increased in subjects with diabetes and are associated with fatal and nonfatal cardiovascular disease. Previously, we have shown that plasma MGO concentrations rapidly increase in the postprandial phase, with a higher increase in individuals with type 2 diabetes. In current study, we investigated whether postprandial MGO formation in plasma and tissues originates from exogenous glucose and whether the increased plasma MGO concentration leads to a fast formation of MGO-derived AGEs. We performed a stable isotope-labelled oral glucose tolerance test (OGTT) in 12 healthy males with universally labelled D(+)13C glucose. Analysis of plasma-labelled 13C3 MGO and glucose levels at 11 time-points during the OGTT revealed that the newly formed MGO during OGTT is completely derived from exogenous glucose. Moreover, a fast formation of protein-bound MGO-derived AGEs during the OGTT was observed. In accordance, ex-vivo incubation of MGO with plasma or albumin showed a rapid decrease in MGO and a fast increase in MGO-derived AGEs. In an intraperitoneal glucose tolerance test in C57BL/6J mice, we confirmed that the formation of postprandial MGO is derived from exogenous glucose in plasma and also showed in tissues that MGO is increased and this is also from exogenous glucose. Collectively, increased formation of MGO during a glucose tolerance test arises from exogenous glucose both in plasma and in tissues, and this leads to a fast formation of MGO-derived AGEs.
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Diabetes Mellitus Tipo 2 , Glucose , Masculino , Animais , Camundongos , Teste de Tolerância a Glucose , Aldeído Pirúvico , Óxido de Magnésio , Produtos Finais de Glicação Avançada , Camundongos Endogâmicos C57BLRESUMO
AIM: To investigate the effects of pyridoxamine (PM), a B6 vitamer and dicarbonyl scavenger, on glycation and a large panel of metabolic and vascular measurements in a randomized double-blind placebo-controlled trial in abdominally obese individuals. MATERIALS AND METHODS: Individuals (54% female; mean age 50 years; mean body mass index 32 kg/m2 ) were randomized to an 8-week intervention with either placebo (n = 36), 25 mg PM (n = 36) or 200 mg PM (n = 36). We assessed insulin sensitivity, ß-cell function, insulin-mediated microvascular recruitment, skin microvascular function, flow-mediated dilation, and plasma inflammation and endothelial function markers. PM metabolites, dicarbonyls and advanced glycation endproducts (AGEs) were measured using ultra-performance liquid chromatography tandem mass spectrometry. Treatment effects were evaluated by one-way ANCOVA. RESULTS: In the high PM dose group, we found a reduction of plasma methylglyoxal (MGO) and protein-bound Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1), as compared to placebo. We found a reduction of the endothelial dysfunction marker soluble vascular cell adhesion molecule-1 (sVCAM-1) in the low and high PM dose group and of soluble intercellular adhesion molecule-1 (sICAM-1) in the high PM dose, as compared to placebo. We found no treatment effects on insulin sensitivity, vascular function or other functional outcome measurements. CONCLUSIONS: This study shows that PM is metabolically active and reduces MGO, AGEs, sVCAM-1 and sICAM-1, but does not affect insulin sensitivity and vascular function in abdominally obese individuals. The reduction in adhesion markers is promising because these are important in the pathogenesis of endothelial damage and atherosclerosis.
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Resistência à Insulina , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Aldeído Pirúvico , Reação de Maillard , Piridoxamina/farmacologia , Piridoxamina/uso terapêutico , Produtos Finais de Glicação Avançada/metabolismo , Óxido de Magnésio , ObesidadeRESUMO
α-Dicarbonyls and advanced glycation end products (AGEs) may contribute to the pathogenesis of insulin resistance by a variety of mechanisms. To investigate whether young insulin-resistant subjects present markers of increased dicarbonyl stress, we determined serum α-dicarbonyls-methylglyoxal, glyoxal, 3-deoxyglucosone; their derived free- and protein-bound, and urinary AGEs using the UPLC/MS-MS method; soluble receptors for AGEs (sRAGE), and cardiometabolic risk markers in 142 (49% females) insulin resistant (Quantitative Insulin Sensitivity Check Index (QUICKI) ≤ 0.319) and 167 (47% females) age-, and waist-to-height ratio-matched insulin-sensitive controls aged 16-to-22 years. The between-group comparison was performed using the two-factor (sex, presence/absence of insulin resistance) analysis of variance; multiple regression via the orthogonal projection to latent structures model. In comparison with their insulin-sensitive peers, young healthy insulin-resistant individuals without diabetes manifest alterations throughout the α-dicarbonyls-AGEs-sRAGE axis, dominated by higher 3-deoxyglucosone levels. Variables of α-dicarbonyls-AGEs-sRAGE axis were associated with insulin sensitivity independently from cardiometabolic risk markers, and sex-specifically. Cleaved RAGE associates with QUICKI only in males; while multiple α-dicarbonyls and AGEs independently associate with QUICKI particularly in females, who displayed a more advantageous cardiometabolic profile compared with males. Further studies are needed to elucidate whether interventions alleviating dicarbonyl stress ameliorate insulin resistance.
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Doenças Cardiovasculares , Resistência à Insulina , Masculino , Feminino , Humanos , Produtos Finais de Glicação Avançada , Estudos de Casos e Controles , InsulinaRESUMO
Type 1 diabetes is an autoimmune disease with no cure, where clinical translation of promising therapeutics has been hampered by the reproducibility crisis. Here, short-term administration of an antagonist to the receptor for advanced glycation end products (sRAGE) protected against murine diabetes at two independent research centers. Treatment with sRAGE increased regulatory T cells (Tregs) within the islets, pancreatic lymph nodes, and spleen, increasing islet insulin expression and function. Diabetes protection was abrogated by Treg depletion and shown to be dependent on antagonizing RAGE with use of knockout mice. Human Tregs treated with a RAGE ligand downregulated genes for suppression, migration, and Treg homeostasis (FOXP3, IL7R, TIGIT, JAK1, STAT3, STAT5b, CCR4). Loss of suppressive function was reversed by sRAGE, where Tregs increased proliferation and suppressed conventional T-cell division, confirming that sRAGE expands functional human Tregs. These results highlight sRAGE as an attractive treatment to prevent diabetes, showing efficacy and reproducibility at multiple research centers and in human T cells.
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Doenças Autoimunes , Diabetes Mellitus Tipo 1 , Animais , Humanos , Insulina/uso terapêutico , Camundongos , Receptor para Produtos Finais de Glicação Avançada/genética , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Reprodutibilidade dos Testes , Linfócitos T ReguladoresRESUMO
Dietary advanced glycation endproducts (AGEs), abundantly present in Westernized diets, are linked to negative health outcomes, but their impact on the gut microbiota has not yet been well investigated in humans. We investigated the effects of a 4-week isocaloric and macronutrient-matched diet low or high in AGEs on the gut microbial composition of 70 abdominally obese individuals in a double-blind parallel-design randomized controlled trial (NCT03866343). Additionally, we investigated the cross-sectional associations between the habitual intake of dietary dicarbonyls, reactive precursors to AGEs, and the gut microbial composition, as assessed by 16S rRNA amplicon-based sequencing. Despite a marked percentage difference in AGE intake, we observed no differences in microbial richness and the general community structure. Only the Anaerostipes spp. had a relative abundance >0.5% and showed differential abundance (0.5 versus 1.11%; p = 0.028, after low- or high-AGE diet, respectively). While the habitual intake of dicarbonyls was not associated with microbial richness or a general community structure, the intake of 3-deoxyglucosone was especially associated with an abundance of several genera. Thus, a 4-week diet low or high in AGEs has a limited impact on the gut microbial composition of abdominally obese humans, paralleling its previously observed limited biological consequences. The effects of dietary dicarbonyls on the gut microbiota composition deserve further investigation.
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Microbioma Gastrointestinal , Produtos Finais de Glicação Avançada , Obesidade , Estudos Transversais , Dieta , Método Duplo-Cego , Produtos Finais de Glicação Avançada/administração & dosagem , Humanos , Obesidade/dietoterapia , Obesidade/microbiologia , RNA Ribossômico 16S/genéticaRESUMO
A Western diet comprises high levels of dicarbonyls and advanced glycation endproducts (AGEs), which may contribute to flares and symptoms in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). We therefore investigated the intake of dietary dicarbonyls and AGEs in IBD and IBS patients as part of the habitual diet, and their association with intestinal inflammation. Food frequency questionnaires from 238 IBD, 261 IBS as well as 195 healthy control (HC) subjects were used to calculate the intake of dicarbonyls methylglyoxal, glyoxal, and 3-deoxyglucosone, and of the AGEs Nε-(carboxymethyl)lysine, Nε-(1-carboxyethyl)lysine and methylglyoxal-derived hydroimidazolone-1. Intestinal inflammation was assessed using faecal calprotectin. The absolute dietary intake of all dicarbonyls and AGEs was higher in IBD and HC as compared to IBS (all p < 0.05). However, after energy-adjustment, only glyoxal was lower in IBD versus IBS and HC (p < 0.05). Faecal calprotectin was not significantly associated with dietary dicarbonyls and AGEs in either of the subgroups. The absolute intake of methylglyoxal was significantly higher in patients with low (<15 µg/g) compared to moderate calprotectin levels (15−<50 µg/g, p = 0.031). The concentrations of dietary dicarbonyls and AGEs generally present in the diet of Dutch patients with IBD or IBS are not associated with intestinal inflammation, although potential harmful effects might be counteracted by anti-inflammatory components in the food matrix.
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Doenças Inflamatórias Intestinais , Síndrome do Intestino Irritável , Humanos , Síndrome do Intestino Irritável/complicações , Lisina , Aldeído Pirúvico , Doenças Inflamatórias Intestinais/complicações , Dieta/efeitos adversos , Produtos Finais de Glicação Avançada/efeitos adversos , Inflamação/complicaçõesRESUMO
BACKGROUND: Dicarbonyls are highly reactive compounds and major precursors of advanced glycation end products (AGEs). Both dicarbonyls and AGEs are associated with development of age-related diseases. Dicarbonyls are formed endogenously but also during food processing. To what extent dicarbonyls from the diet contribute to circulating dicarbonyls and AGEs in tissues is unknown. OBJECTIVES: To examine cross-sectional associations of dietary dicarbonyl intake with plasma dicarbonyl concentrations and skin AGEs. METHODS: In 2566 individuals of the population-based Maastricht Study (age: 60 ± 8 y, 50% males, 26% with type 2 diabetes), we estimated habitual intake of the dicarbonyls methylglyoxal (MGO), glyoxal (GO), and 3-deoxyglucosone (3-DG) by combining FFQs with our dietary dicarbonyl database of MGO, GO, and 3-DG concentrations in > 200 commonly consumed food products. Fasting plasma concentrations of MGO, GO, and 3-DG were measured by ultra-performance liquid chromatography-tandem mass spectrometry. Skin AGEs were measured as skin autofluorescence (SAF), using the AGE Reader. Associations of dietary dicarbonyl intake with their respective plasma concentrations and SAF (all standardized) were examined using linear regression models, adjusted for age, sex, potential confounders related to cardiometabolic risk factors, and lifestyle. RESULTS: Median intake of MGO, GO, and 3-DG was 3.6, 3.5, and 17 mg/d, respectively. Coffee was the main dietary source of MGO, whereas this was bread for GO and 3-DG. In the fully adjusted models, dietary MGO was associated with plasma MGO (ß: 0.08; 95% CI: 0.02, 0.13) and SAF (ß: 0.12; 95% CI: 0.07, 0.17). Dietary GO was associated with plasma GO (ß: 0.10; 95% CI: 0.04, 0.16) but not with SAF. 3-DG was not significantly associated with either plasma 3-DG or SAF. CONCLUSIONS: Higher habitual intake of dietary MGO and GO, but not 3-DG, was associated with higher corresponding plasma concentrations. Higher intake of MGO was also associated with higher SAF. These results suggest dietary absorption of MGO and GO. Biological implications of dietary absorption of MGO and GO need to be determined. The study has been approved by the institutional medical ethical committee (NL31329.068.10) and the Minister of Health, Welfare and Sports of the Netherlands (Permit 131088-105234-PG).
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Desoxiglucose/análogos & derivados , Dieta/efeitos adversos , Glioxal/sangue , Aldeído Pirúvico/sangue , Pele/química , Idoso , Cromatografia Líquida , Estudos Transversais , Desoxiglucose/sangue , Diabetes Mellitus Tipo 2/sangue , Inquéritos sobre Dietas , Exposição Dietética/análise , Jejum/sangue , Feminino , Produtos Finais de Glicação Avançada/sangue , Humanos , Modelos Lineares , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Países Baixos , Imagem ÓpticaRESUMO
Advanced glycation endproducts (AGEs) are involved in several diseases, including NAFLD and NASH. RAGE is the main receptor mediating the pro-inflammatory signalling induced by AGEs. Therefore, targeting of RAGE has been proposed for prevention of chronic inflammatory diseases. However, the role of RAGE in the development of NAFLD and NASH remains poorly understood. We thus aimed to analyse the effect of obesity on AGEs accumulation, AGE-receptors and AGE-detoxification, and whether the absence of RAGE might improve hepatosteatosis and inflammation, by comparing the liver of lean control, obese (LeptrDb-/-) and obese RAGE-deficient (RAGE-/- LeptrDb-/-) mice. Obesity induced AGEs accumulation and RAGE expression with hepatosteatosis and inflammation in LeptrDb-/-, compared to lean controls. Despite the genetic deletion of RAGE in the LeptrDb-/- mice, high levels of intrahepatic AGEs were maintained accompanied by decreased expression of the protective AGE-receptor-1, impaired AGE-detoxifying system glyoxalase-1, and increased expression of the alternative AGE-receptor galectin-3. We also found sustained hepatosteatosis and inflammation as determined by persistent activation of the lipogenic SREBP1c and proinflammatory NLRP3 signalling pathways. Thus, RAGE targeting is not effective in the prevention of NAFLD in conditions of obesity, likely due to the direct liver specific crosstalk of RAGE with other AGE-receptors and AGE-detoxifying systems.
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Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Receptor para Produtos Finais de Glicação Avançada/genética , Receptor para Produtos Finais de Glicação Avançada/fisiologia , Tecido Adiposo/metabolismo , Animais , Feminino , Deleção de Genes , Inflamassomos , Inflamação/metabolismo , Lipídeos/química , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Receptores Imunológicos/metabolismo , Transdução de SinaisRESUMO
SCOPE: Dietary advanced glycation endproducts (AGEs) are associated with negative biological effects, possibly due to accumulation in plasma and tissues and through modulation of inflammation and gut microbiota. Whether these biological consequences are reversible by limiting dietary AGE intake is unknown. METHODS AND RESULTS: Young healthy C57BL/6 mice were fed a standard chow (n = 10) or a baked chow high AGE-diet (n = 10) (~1.8-6.9 fold increased protein-bound Nε-(carboxymethyl)lysine (CML), Nε-(1-carboxyethyl)lysine (CEL), and Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1)) for 10 weeks or a switch diet with baked chow for 5 weeks followed by 5 weeks of standard chow (n = 10). We assessed accumulation of AGEs in plasma, kidney, and liver and measured inflammatory markers and gut microbial composition. After 10 weeks of baked chow, a substantial panel of AGEs were increased in plasma, liver, and kidney. These increases were normalized after the switch diet. The inflammatory z-score increased after the baked chow diet. Gut microbial composition differed significantly between groups, with enriched Dubosiella spp. dominating these alterations. CONCLUSION: A high AGE-diet led to an increase of AGEs in plasma, kidney, and liver and to more inflammation and modification of the gut microbiota. These effects were reversed or discontinued by a diet lower in AGEs.
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Microbioma Gastrointestinal , Produtos Finais de Glicação Avançada , Animais , Dieta , Inflamação , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Mechanisms by which advanced glycation end products (AGEs) contribute to type 1 diabetes (T1D) pathogenesis are poorly understood. Since life-long pharmacotherapy with alagebrium chloride (ALT) slows progression to experimental T1D, we hypothesized that acute ALT therapy delivered prediabetes, may be effective. However, in female, non-obese diabetic (NODShiLt) mice, ALT administered prediabetes (day 50-100) did not protect against experimental T1D. ALT did not decrease circulating AGEs or their precursors. Despite this, pancreatic ß-cell function was improved, and insulitis and pancreatic CD45.1+ cell infiltration was reduced. Lymphoid tissues were unaffected. ALT pre-treatment, prior to transfer of primed GC98 CD8+ T cell receptor transgenic T cells, reduced blood glucose concentrations and delayed diabetes, suggesting islet effects rather than immune modulation by ALT. Indeed, ALT did not reduce interferon-γ production by leukocytes from ovalbumin-pre-immunised NODShiLt mice and NODscid recipients given diabetogenic ALT treated NOD splenocytes were not protected against T1D. To elucidate ß-cell effects, NOD-derived MIN6N8 ß-cell major histocompatibility complex (MHC) Class Ia surface antigens were examined using immunopeptidomics. Overall, no major changes in the immunopeptidome were observed during the various treatments with all peptides exhibiting allele specific consensus binding motifs. As expected, longer MHC Class Ia peptides were captured bound to H-2Db than H-2Kb under all conditions. Moreover, more 10-12 mer peptides were isolated from H-2Db after AGE modified bovine serum albumin (AGE-BSA) treatment, compared with bovine serum albumin (BSA) or AGE-BSA+ALT treatment. Proteomics of MIN6N8 cells showed enrichment of processes associated with catabolism, the immune system, cell cycling and presynaptic endocytosis with AGE-BSA compared with BSA treatments. These data show that short-term ALT intervention, given prediabetes, does not arrest experimental T1D but transiently impacts ß-cell function.
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BACKGROUND AND AIMS: Vitamin B6 is involved in a large spectrum of physiological processes and comprises of the vitamers pyridoxamine (PM), pyridoxal (PL), pyridoxine (PN), and their phosphorylated derivatives including the biological active pyridoxal 5'-phosphate (PLP). While PN toxicity is known to complicate several treatments, PM has shown promise in relation to the treatment of metabolic and age-related diseases by blocking oxidative degradation and scavenging toxic dicarbonyl compounds and reactive oxygen species. We aimed to assess the metabolization of oral PM supplements in a single and three daily dose. MATERIALS AND METHODS: We optimized and validated a method for the quantification of the B6 vitamers in plasma and urine using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Five healthy volunteers were recruited to study PM metabolization after a single oral dose of 200 mg PM or a three daily dose of 67 mg PM. A third protocol was implemented as control for dietary intake. Venous blood samples, 24 h urine and fasted second void urine samples were collected. RESULTS: After a single oral dose of 200 mg PM, plasma PM increased in the first 3 h to a maximum of 2324 ± 266 nmol/L. While plasma PM levels returned to baseline after ~10 h of PM intake, PLP increased to a maximum of 2787 ± 329 nmol/L and reached a plateau. We found a small increase of PN to a maximum of 13.5 ± 2.1 nmol/L; it was nearly undetectable after ~12 h. With a three daily dose of 67 mg PM we observed an increase and decline of plasma PM, PL, and PN concentrations after each PM intake. PLP showed a similar increase as in the single dose protocol and accumulated over time. CONCLUSION: In this study we showed high plasma levels of PM after oral PM supplementation. We found steadily increasing levels of the biologically active PLP, with minimal formation of PN. The B6 vitamer PM is an interesting supplement as an inhibitor of harmful processes in metabolic diseases and for the treatment of vitamin B6 deficiency. CLINICAL TRIAL REGISTRY: The study was approved by the Medical Ethics Committee of Maastricht University (NL) and was registered at ClinicalTrials.gov as NCT02954588.
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Suplementos Nutricionais , Piridoxamina/administração & dosagem , Vitamina B 6/sangue , Vitamina B 6/urina , Adulto , Cromatografia Líquida de Alta Pressão , Feminino , Voluntários Saudáveis , Humanos , Masculino , Fosfato de Piridoxal/sangue , Fosfato de Piridoxal/urina , Piridoxamina/sangue , Piridoxamina/urina , Piridoxina/sangue , Piridoxina/urina , Espectrometria de Massas em Tandem , Deficiência de Vitamina B 6/terapiaRESUMO
AIMS: Dicarbonyl compounds contribute to the formation of advanced glycation endproducts (AGEs) and the development of insulin resistance and vascular complications. Dicarbonyl stress may already be detrimental in obesity. We evaluated whether diet-induced weight loss can effectively reverse dicarbonyl stress in abdominally obese men. MATERIALS AND METHODS: Plasma samples were collected from lean (n = 25) and abdominally obese men (n = 52) in the fasting state, and during a mixed meal test (MMT). Abdominally obese men were randomized to 8 weeks of dietary weight loss or habitual diet, followed by a second MMT. The α-dicarbonyls methylglyoxal (MGO), glyoxal (GO) and 3-deoxyglucosone (3-DG) and AGEs were measured by UPLC-MS/MS. Skin autofluorescence (SAF) was measured using the AGE reader. T-tests were used for the cross-sectional analysis and ANCOVA to assess the treatment effect. RESULTS: Postprandial glucose, MGO and 3-DG concentrations were higher in obese men as compared to lean men (p < 0.05 for all). Fasting dicarbonyls, AGEs, and SAF were not different between lean and obese men. After the weight loss intervention, fasting MGO levels tended to decrease by 25 nmol/L (95%-CI: -51-0.5; p = 0.054). Postprandial dicarbonyls were decreased after weight loss as compared to the control group: iAUC of MGO decreased by 57% (5280 nmol/Lâmin; 95%-CI: 33-10526; p = 0.049), of GO by 66% (11,329 nmol/Lâmin; 95%-CI: 495-22162; p = 0.041), and of 3-DG by 45% (20,175 nmol/Lâmin; 95%-CI: 5351-35000; p = 0.009). AGEs and SAF did not change significantly after weight loss. CONCLUSION: Abdominal obesity is characterized by increased postprandial dicarbonyl stress, which can be reduced by a weight loss intervention. Registered under ClinicalTrials.gov Identifier no. NCT01675401.
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Dieta Redutora , Obesidade Abdominal/dietoterapia , Período Pós-Prandial , Estresse Fisiológico , Redução de Peso/fisiologia , Adulto , Aldeído-Desidrogenase Mitocondrial/genética , Aldeído-Desidrogenase Mitocondrial/metabolismo , Aldeído Redutase/genética , Aldeído Redutase/metabolismo , Estudos Transversais , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Lactoilglutationa Liase/genética , Lactoilglutationa Liase/metabolismo , MasculinoRESUMO
Dicarbonyls are reactive precursors of advanced glycation endproducts. They are formed endogenously and during food processing. Currently, a comprehensive database on dicarbonyls in foods that covers the entire range of food groups is lacking, limiting knowledge about the amount of dicarbonyls that is ingested via food. The aim of this study was to analyze the dicarbonyls methylglyoxal (MGO), glyoxal (GO), and 3-deoxyglucosone (3-DG) in commonly-consumed products in a Western diet. We validated a UHPLC-MS/MS method to quantify MGO, GO, and 3-DG. We present a dietary dicarbonyl database of 223 foods and drinks. Total dicarbonyl concentrations were highest in dried fruit, Dutch spiced cake, and candy bars (>400 mg/kg). Total dicarbonyl concentrations were lowest in tea, dairy, light soft drinks, and rice (<10 mg/kg). The presented database of MGO, GO, and 3-DG opens the possibility to accurately estimate dietary exposure to these dicarbonyls, and explore their physiological impact on human health.
Assuntos
Bebidas/análise , Bases de Dados Factuais , Análise de Alimentos/métodos , Compostos Orgânicos/análise , Manipulação de Alimentos , Humanos , Compostos Orgânicos/química , Espectrometria de Massas em TandemRESUMO
OBJECTIVE: Diabetes is a risk factor for severe limb ischemia (SLI), a condition associated with high mortality, morbidity, and limb loss. The reactive glucose-derived dicarbonyl methylglyoxal (MGO) is a major precursor for advanced glycation end products (AGEs) and a potential driver of cardiovascular disease. We investigated whether plasma MGO levels are associated with poor outcomes in SLI. RESEARCH DESIGN AND METHODS: We measured plasma levels of MGO, free AGEs, and d-lactate, the detoxification end product of MGO, with ultraperformance liquid chromatography-tandem mass spectrometry at baseline in 160 patients (64.8 ± 13.3 years, 67.5% male, 37.5% with diabetes) with no-option SLI and recorded major adverse outcomes (n = 86, comprising n = 53 deaths and n = 49 amputations [first event counted]) over the 5-year follow-up. Data were analyzed with linear or Cox regression, after Ln-transformation of the independent variables, adjusted for sex, age, trial arm, diabetes, estimated glomerular filtration rate, systolic blood pressure, cholesterol levels, and BMI. Associations are reported per 1 SD plasma marker. RESULTS: Higher plasma MGO levels were associated with more adverse outcomes (relative risk 1.44; 95% CI 1.11-1.86) and amputations separately (1.55; 1.13-2.21). We observed a similar but weaker trend for mortality (1.28; 0.93-1.77). The MGO-derived AGE Nε-(carboxyethyl)lysine was also associated with more adverse outcomes (1.46; 1.00-2.15) and amputations (1.71; 1.04-2.79). d-Lactate was not associated with adverse incident outcomes. Higher plasma MGO levels were also associated with more inflammation and white blood cells and fewer progenitor cells. CONCLUSIONS: Plasma MGO levels are associated with adverse outcomes in SLI. Future studies should investigate whether MGO-targeting therapies improve outcomes in SLI.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus , Amputação Cirúrgica , Estudos de Casos e Controles , Feminino , Produtos Finais de Glicação Avançada , Humanos , Isquemia , Masculino , Aldeído PirúvicoRESUMO
AIMS: Non-invasively assessed skin autofluorescence (SAF) measures advanced glycation endproducts (AGEs) in the dermis. SAF correlates with dermal AGEs in Caucasians and Asians, but studies in dark-skinned subjects are lacking. In this pilot we aimed to assess whether SAF signal is representative of intrinsic fluorescence (IF) and AGE accumulation in dark skin. METHODS: Skin biopsies were obtained in 12 dark-skinned subjects (6 healthy subjects, median age 22 years; 6 diabetes mellitus (DM) subjects, 65 years). SAF was measured with the AGE Reader, IF using confocal microscopy, and AGE distribution with specific antibodies. CML and MG-H1 were quantified with UPLC-MS/MS and pentosidine with HPLC and fluorescent detection. RESULTS: SAF correlated with IF from the dermis (405nm, r = 0.58, p < 0.05), but not with CML (r = 0.54, p = 0.07). CML correlated with IF from the dermis (405nm, r = 0.90, p < 0.01). UV reflectance and the coefficient of variation of SAF were negatively correlated (r = -0.80, p < 0.01). CML and MG-H1 were predominantly present around blood vessels, in collagen and fibroblasts in the dermis. CONCLUSION: This proof of concept study is the first to compare non-invasive SAF with AGE levels measured in skin biopsies in dark-skinned subjects. SAF did not correlate with individual AGEs from biopsies, but was associated with IF. However, the intra-individual variance was high, limiting its application in dark-skinned subjects on an individual basis.