Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.004
Filtrar
1.
Food Chem ; 373(Pt A): 131451, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-34717081

RESUMO

The present study investigated the influence of in vitro stimulated digestion system on the content of glyoxal and methylglyoxal in commercial cookies. Glyoxal and methylglyoxal levels in different cookie samples were analyzed before and after in vitro digestion with High Performance Liquid Chromatography. Initial glyoxal and methylglyoxal values ranged between 42.9 and 126.6 µg/100 g, and between 22.9 and 507.3 µg/100 g, respectively. After in vitro digestion, formation of glyoxal and methylglyoxal values were increased up to 645% and 698%, respectively. The results revealed that in vitro stimulated digestion conditions strongly increased the amount of glyoxal and methylglyoxal in cookies. The amount of fructose was found to be more effective on the formation of both GO and MGO than those of glucose and sucrose. Further studies are needed to extensively investigate glyoxal and methylglyoxal formation under in vitro conditions in such foods.


Assuntos
Glioxal , Aldeído Pirúvico , Cromatografia Líquida de Alta Pressão , Alimentos , Glucose
2.
Food Chem ; 371: 131137, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34562777

RESUMO

The role of amino acids and α-dicarbonyls in the flavor formation of Amadori rearrangement product (ARP) during thermal processing was investigated. Comparisons of the volatile compounds and their concentrations when N-(1-deoxy-α-d-ribulos-1-yl)-glycine reacted with different amino acids or glyoxal (GO) at 100 °C were executed. Additional amino acids, such as glycine (Gly), in ARP models contributed to the diversity of furanoids by the chain elongation of the derived formaldehyde. Whereas the monoanion of additional glutamic acid acted as nucleophile, favored 2-ethyl-3,5-dimethylpyrazine and 2,5-dimethylpyrazine formation; the nonionized amino group of additional lysine were involved in α-dicarbonyls formation, causing pyrazine and methylpyrazine accumulation in the ARP model. Moreover, the high dosage and pH stabilization of additional GO probably promoted the ARP degradation and deoxyosones retro-aldol cleavage, resulting in methylpyrazine rather than furanoids formation. The present work provided the guidance for the controlled flavor formation of ARP in industrial application.


Assuntos
Aminoácidos , Glicina , Aromatizantes , Glioxal , Reação de Maillard
3.
Food Chem ; 371: 131141, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34598119

RESUMO

The aim of this study was to investigate sourdough impact on the in vitro bioaccessibility of Glyoxal (GO) and methylglyoxal (MGO). Five sourdough bread and one white bread (control bread) were prepared to observe sourdough influence on GO and MGO levels before and after in vitro digestion. GO and MGO levels increased in all breads after in vitro digestion. The highest increase in GO and MGO levels was realized in the control bread with bioaccessibility indexes (BIGO and BIMGO) of 8.67 and 4.14, respectively, whereas BIGO and BIMGO in sourdough breads were found in the range of 1.65 to 2.65 and 1.73 to 2.97, respectively. The extent of Maillard reaction (MR) in control bread was confirmed by FAST method. The lower increase in GO and MGO compounds after in vitro digestion thanks to sourdough addition may reduce bread's contribution of AGEs accumulation in the body.


Assuntos
Pão , Aldeído Pirúvico , Digestão , Fermentação , Glioxal , Triticum
4.
Curr Drug Deliv ; 18(7): 1027-1040, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34911421

RESUMO

AIMS: This study aims to investigate the role of glyoxal modified LDL in the immunopathology of diabetes and cardiovascular disease. BACKGROUND: Glycoxidation of proteins is widely studied in relation to diabetes and cardiovascular disease. OBJECTIVE: This study probed the glyoxal mediated modifications in LDL, analyzed the immunogenicity of the glycated LDL and ascertained the presence of circulating antibodies against modified LDL in patients with type 2 diabetes mellitus (T2DM), coronary artery disease (CAD) and patients with both (T2DM+CAD). METHODS: Glyoxal mediated modifications in LDL were studied by multiple spectroscopic techniques, high-performance liquid chromatography and electron microscopy. Immunization studies were carried in New Zealand rabbits. The presence of antibodies against glyoxal modified LDL in immunized rabbits and human subjects was analyzed by ELISA. RESULTS: Glyoxal altered the structural integrity of LDL and led to the formation of AGEs. It decreased the alpha-helix content of LDL; increased ß sheet formation, increased carbonyl content and decreased free lysine and arginine content. Modified LDL showed aggregation, generation of of Nε- (Carboxymethyl) lysine and the formation of amorphous type aggregates. It exhibited high antigenicity and generated a specific immune response that shared common antigenic determinants with other glycated proteins. Direct binding data showed the presence of anti-glyoxal modified LDL antibodies in patients with T2DM, CAD and patients with both T2DM and CAD. Further analysis in competitive binding assay revealed specific binding characteristics of auto-antibodies. Sera from patients with T2DM+CAD exhibited the highest binding with glyoxal modified LDL. CONCLUSION: Glyoxal-modified LDL has neo-antigenic determinants that cause the generation of circulating antibodies in diabetes and coronary artery disease. The study might have potential relevance in biomarker development.


Assuntos
Doença da Artéria Coronariana , Diabetes Mellitus Tipo 2 , Animais , Autoanticorpos , Epitopos , Glioxal , Humanos , Coelhos
5.
J Agric Food Chem ; 69(50): 15374-15383, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34905354

RESUMO

The reaction of the N6-amino group of lysine residues and 1,2-dicarbonyl compounds during Maillard processes leads to advanced glycation end products (AGEs). In the present work, we deliver a comprehensive analysis of changes of carbohydrates, dicarbonyl structures, and 11 AGEs during the grilling of porcine meat patties. While raw meat contained mainly glyoxal-derived N6-carboxymethyl lysine (CML), grilling led to an increase of predominantly methylglyoxal-derived AGEs N6-carboxyethyl lysine (CEL), N6-lactoyl lysine, methylglyoxal lysine dimer (MOLD), and methylglyoxal lysine amide (MOLA). Additionally, we identified and quantitated a novel methylglyoxal-derived amidine compound N1,N2-di-(5-amino-5-carboxypentyl)-2-lactoylamidine (methylglyoxal lysine amide, MGLA) in heated meat. Analysis of carbohydrates suggested that approximately 50% of the methylglyoxal stemmed from the fragmentation of triosephosphates during the heat treatment. Surprisingly, N6-lactoyl lysine was the major AGE, and based on model incubations, we propose that approximately 90% must be explained by the nonenzymatic acylation of lysine through S-lactoylglutathione, which was quantitated for the first time in meat herein.


Assuntos
Culinária , Produtos Finais de Glicação Avançada/análise , Glioxal , Carne de Porco , Aldeído Pirúvico , Animais , Reação de Maillard , Suínos
6.
J Enzyme Inhib Med Chem ; 36(1): 2010-2015, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34517737

RESUMO

Tumours reprogram their metabolism to acquire an evolutionary advantage over normal cells. However, not all such metabolic pathways support energy production. An example of these metabolic pathways is the Methylglyoxal (MG) one. This pathway helps maintain the redox state, and it might act as a phosphate sensor that monitors the intracellular phosphate levels. In this work, we discuss the biochemical step of the MG pathway and interrelate it with cancer.


Assuntos
Glioxal/metabolismo , Neoplasias/metabolismo , Glioxal/química , Humanos , Estrutura Molecular
7.
Environ Sci Technol ; 55(17): 11549-11556, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34378922

RESUMO

Organic reactions in atmospheric particles impact human health and climate, such as by the production of brown carbon. Previous work suggests that reactions are faster in particles than in bulk solutions because of higher reactant concentrations and pronounced surface-mediated processes. Additionally, dialdehydes may have accelerated reactions in particles, as has been shown for the glyoxal reaction with ammonium sulfate (AS). Here, we examine the competition between evaporation and reaction of butenedial, a semivolatile dialdehyde, and reduced nitrogen (NHX) in bulk solutions and levitated particles with mass spectrometry (MS). Pyrrolinone is the major product of butenedial/AS bulk solutions, indicating brown carbon formation via accretion reactions. By contrast, pyrrolinone is completely absent in all MS measurements of comparable levitated particles suspended in a pure N2 stream. Pyrrolinone is only produced in levitated butenedial particles exposed to gas-phase ammonia, without enhanced reaction kinetics previously observed for glyoxal and other systems. Despite butenedial's large Henry's law constant and fast reaction with NHX compared to glyoxal, the brown carbon pathway competes with evaporation only in polluted regions with extreme NHX. Therefore, accurate knowledge of effective volatilities or Henry's law constants for complex aerosol matrices is required when chemistry studied in bulk solutions is extrapolated to atmospheric particles.


Assuntos
Carbono , Água , Aerossóis , Sulfato de Amônio , Glioxal , Humanos
8.
J Agric Food Chem ; 69(28): 7960-7968, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34240860

RESUMO

One crucial aspect of the Maillard reaction is the formation of reactive α-dicarbonyl structures like glyoxal, which are prone toward further reactions with proteins, e.g., the N6-amino group of lysine. The initially formed labile glyoxal-imine was previously established as a key intermediate in the formation of the advanced glycation end products N6-carboxymethyl lysine (CML), glyoxal lysine amide (GOLA), glyoxal lysine dimer (GOLD), and N6-glycolyl lysine (GALA). Here, we introduce a novel amidine cross-link structure N1,N2-bis-(5-amino-5-carboxypentyl)-2-hydroxy-acetamidine (glyoxal lysine amidine, GLA), which is formed exclusively from glyoxal through the same isomerization cascade. After independent synthesis of the authentic reference standard, we were able to quantitate this cross-link in incubations of 40 mM N2-t-Boc-lysine with glyoxal and various sugars (40-100 mM) under mild conditions (pH 7.4, 37 °C) using an HPLC-MS/MS method. Furthermore, incubations of proteins (6 mg/mL) with 50 mM glyoxal confirmed the cross-linking by GLA, which was additionally identified in acidic hydrolyzed proteins of butter biscuits after HPLC enrichment.


Assuntos
Glioxal , Lisina , Amidinas , Produtos Finais de Glicação Avançada , Reação de Maillard , Espectrometria de Massas em Tandem
9.
Molecules ; 26(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207740

RESUMO

In this study, formaldehyde-free bioresin adhesives were synthesised from lignin and tannin, which were obtained from softwood bark. The extraction was done via organosolv treatment and hot water extraction, respectively. A non-volatile, non-toxic aldehyde, glyoxal, was used as a substitute for formaldehyde in order to modify the chemical structure of both the lignin and tannin. The glyoxal modification reaction was confirmed by ATR-FTIR spectroscopy. Three different resin formulations were prepared using modified lignin along with the modified tannin. The thermal properties of the modified lignin, tannin, and the bioresins were assessed by DSC and TGA. When the bioresins were cured at a high temperature (200 °C) by compression moulding, they exhibited higher thermal stability as well as an enhanced degree of cross-linking compared to the low temperature-cured bioresins. The thermal properties of the resins were strongly affected by the compositions of the resins as well as the curing temperatures.


Assuntos
Lignina/química , Picea/química , Casca de Planta/química , Resinas Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Taninos/química , Adesivos/química , Glioxal/química , Química Verde/instrumentação , Química Verde/métodos , Temperatura Alta , Madeira/química
10.
Int J Mol Sci ; 22(12)2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208633

RESUMO

The clinical application of human platelet lysate (HPL) holds promise for tissue regeneration, and the development of an efficient vehicle for its delivery is desired. Chitosan-based hydrogels are potential candidates, but they often exhibit weak mechanical properties. In this study, a chitosan/gelatin (CS-GE) hydrogel crosslinked by glyoxal was fabricated for sustained release of HPL. The influence of HPL on Hs68 fibroblast and human umbilical vein endothelial cell (HUVEC) culture was evaluated, and we found that supplementing 5% HPL in the medium could significantly improve cell proliferation relative to supplementing 10% fetal bovine serum (FBS). Moreover, HPL accelerated the in vitro wound closure of Hs68 cells and facilitated the tube formation of HUVECs. Subsequently, we fabricated CS-GE hydrogels crosslinked with different concentrations of glyoxal, and the release pattern of FITC-dextrans (4, 40 and 500 kDa) from the hydrogels was assessed. After an ideal glyoxal concentration was determined, we further characterized the crosslinked CS-GE hydrogels encapsulated with different amounts of HPL. The HPL-incorporated hydrogel was shown to significantly promote the proliferation of Hs68 cells and the migration of HUVECs. Moreover, the release pattern of transforming growth factor-ß1 (TGF-ß1) and platelet-derived growth factor-BB (PDGF-BB) from hydrogel was examined in vitro, demonstrating a sustained release profile of the growth factors. Finally, the chick chorioallantoic membrane assay revealed that HPL encapsulation in the hydrogel significantly stimulated angiogenesis in ovo. These results demonstrate the great potential of the crosslinked CS-GE hydrogel to serve as an effective delivery system for HPL to promote tissue regeneration.


Assuntos
Produtos Biológicos/farmacologia , Plaquetas/metabolismo , Quitosana , Gelatina , Glioxal , Hidrogéis , Regeneração/efeitos dos fármacos , Proliferação de Células , Quitosana/química , Dextranos/química , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Gelatina/química , Glioxal/química , Células Endoteliais da Veia Umbilical Humana , Humanos , Hidrogéis/química , Neovascularização Fisiológica , Porosidade , Cicatrização/efeitos dos fármacos
11.
Environ Sci Technol ; 55(12): 7786-7793, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-34060825

RESUMO

The composition of organic aerosol has a pivotal influence on aerosol properties such as toxicity and cloud droplet formation capability, which could affect both climate and air quality. However, a comprehensive and fundamental understanding of the chemical and physical processes that occur in nanometer-sized atmospheric particles remains a challenge that severely limits the quantification and predictive capabilities of aerosol formation pathways. Here, we investigated the effects of a fundamental and hitherto unconsidered physical property of nanoparticles-the Laplace pressure. By studying the reaction of glyoxal with ammonium sulfate, both ubiquitous and important atmospheric constituents, we show that high pressure can significantly affect the chemical processes that occur in atmospheric ultrafine particles (i.e., particles < 100 nm). Using high-resolution mass spectrometry and UV-vis spectroscopy, we demonstrated that the formation of reaction products is strongly (i.e., up to a factor of 2) slowed down under high pressures typical of atmospheric nanoparticles. A size-dependent relative rate constant is determined and numerical simulations illustrate the reduction in the production of the main glyoxal reaction products. These results established that the high pressure inside nanometer-sized aerosols must be considered as a key property that significantly impacts chemical processes that govern atmospheric aerosol growth and evolution.


Assuntos
Glioxal , Material Particulado , Aerossóis/análise , Sulfato de Amônio
12.
Chem Commun (Camb) ; 57(52): 6380-6383, 2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34081065

RESUMO

A unique and highly water-soluble ICT-based fluorescent probe is developed for efficient detection and discrimination of reactive monocarbonyl formaldehyde (FA) from dicarbonyl methylglyoxal (MGO)/glyoxal (GO) by modulating the ICT process, which was confirmed by photophysical and TD-DFT analysis. The probe is applied in cellular imaging and quantifying FA in preserved food and MGO in manuka honey.


Assuntos
Corantes Fluorescentes/química , Análise de Alimentos/métodos , Formaldeído/análise , Glioxal/análise , Aldeído Pirúvico/análise , 2-Naftilamina/análogos & derivados , 2-Naftilamina/química , Animais , Teoria da Densidade Funcional , Células Hep G2 , Mel/análise , Humanos , Limite de Detecção , Microscopia de Fluorescência , Alimentos Marinhos/análise , Solubilidade
13.
Mol Cell Biochem ; 476(10): 3613-3622, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34028646

RESUMO

Molecular hydrogen (H2) is recognized as a gaseous antioxidant, and it is expected to ameliorate various disorders related to oxidative stress and inflammation. However, there are still many unclear points regarding its effectiveness in the skin. Therefore, the purpose of this study was to examine the protective effect of H2 against ultraviolet (UV) irradiation-related stress injury in human epidermal HaCaT cells. We investigated the effects of H2 against three types of UV-derived oxidative stress using human skin keratinocytes: hydrogen peroxide (H2O2)-induced oxidative stress, tert-butyl hydroperoxide (t-BuOOH)-induced lipid peroxidation stress, and glyoxal-induced carbonyl stress. Our results showed that H2 exerted cytoprotective effects against stress induced by H2O2, t-BuOOH, and glyoxal. Furthermore, our results also revealed that H2 suppressed H2O2-induced increases in intracellular peroxide and H2O2 levels, and suppressed the progression of lipid peroxidation. Taken together, our results demonstrate that H2 can exert protective effects against oxidative stress-, lipid peroxidation-, and carbonyl stress-induced cellular injuries in human keratinocytes, partly mediated via suppression of intracellular oxidative stress and peroxide generation. Therefore, H2 is expected to be utilized as an effective and attractive component in cosmetic formulations in the future.


Assuntos
Derme/lesões , Glioxal/toxicidade , Peróxido de Hidrogênio/toxicidade , Hidrogênio/farmacologia , Queratinócitos/metabolismo , Linhagem Celular , Derme/metabolismo , Derme/patologia , Humanos , Queratinócitos/patologia
14.
J Pharm Biomed Anal ; 201: 114097, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33933705

RESUMO

During diabetes human serum albumin (HSA), an important drug transport protein, can be modified by agents such as glyoxal (Go) and methylglyoxal (MGo) to form advanced glycation end-products. High-performance affinity microcolumns and zonal elution competition studies were used to compare interactions by the anti-diabetic drugs repaglinide and nateglinide with normal and Go- or MGo-modified HSA at Sudlow sites I and II of this protein. Both drugs had their strongest binding at Sudlow site II for the normal and modified forms of HSA. The association equilibrium constants at this site for repaglinide and nateglinide with normal HSA were 6.1 (± 0.2) × 104 M-1 and 7.1 (± 0.8) × 105 M-1, respectively, at pH 7.4 and 37°C; these values increased by up to 3.6-fold for repaglinide and decreased by up to 45-55 % for nateglinide when HSA was modified by Go or MGo at levels seen in prediabetes or diabetes. Both drugs were also found to bind at Sudlow site I, with association equilibrium constants at this site on normal HSA of 4.2 (± 0.3) × 104 M-1 for repaglinide and 5.0 (± 0.1) × 104 M-1 for nateglinide. The binding strength for repaglinide at Sudlow site I increased by 1.3- to 1.7-fold with the Go-modified HSA and decreased slightly (i.e., up to 19 %) for the MGo-modified HSA, while nateglinide showed only a small or insignificant change in binding with the same modified HSA samples. These results indicated that binding by repaglinide and nateglinide with HSA can be altered significantly by modification of this protein with Go or MGo, making these modifications of potential interest in the treatment of patients with these drugs during diabetes.


Assuntos
Glioxal , Aldeído Pirúvico , Carbamatos , Cromatografia de Afinidade , Glicosilação , Humanos , Nateglinida , Piperidinas , Ligação Proteica , Albumina Sérica/metabolismo , Albumina Sérica Humana/metabolismo
15.
Food Chem ; 358: 129884, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933976

RESUMO

The ability of histidine to scavenge sugar-derived 1,2-dicarbonyl compounds was investigated using aqueous methanolic model systems containing histidine or histamine in the presence of glucose, methylglyoxal, or glyoxal. The samples were prepared either at room temperature (RT) or at 150 °C and analyzed using ESI-qTOF-MS/MS and isotope labeling technique. Replacing glucose with [U-13C6]glucose allowed the identification of glucose carbon atoms incorporated in the products. Various sugar-generated carbonyl compounds ranging in size from C1 to C6 were captured by histidine or histamine. The majority of the fragments incorporated were either C3 or C2 units originating from glyoxal (C2) or methylglyoxal (C3). The ESI-qTOF-MS/MS analysis indicated that histamine could react with either of the two carbonyl carbons of methylglyoxal utilizing the α-amino group and/or the imidazolium moiety. Furthermore, when histidine was added to 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) generating model system, it completely suppressed the formation of PhIP due to scavenging of phenylacetaldehyde.


Assuntos
Carnosina/química , Histamina/química , Histidina/química , Aldeído Pirúvico/química , Acetaldeído/análogos & derivados , Acetaldeído/química , Carnosina/metabolismo , Manipulação de Alimentos , Sequestradores de Radicais Livres/química , Glucose/química , Glioxal/química , Glioxal/metabolismo , Histidina/metabolismo , Imidazóis/química , Marcação por Isótopo , Aldeído Pirúvico/metabolismo , Açúcares/química , Espectrometria de Massas em Tandem , Temperatura
16.
J Phys Chem B ; 125(21): 5559-5571, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34019761

RESUMO

Alzheimer's disease (AD) is characterized by the presence of extracellular senile plaques formed by ß-amyloid (Aß) peptides in the patient's brain. Previous studies have shown that the plaques in the AD brains are colocalized with the advanced glycation end products, which is mainly formed from a series of nonenzymatic reactions of proteins with reducing sugars or reactive dicarbonyls. Glycation was also demonstrated to increase the neurotoxicity of the Aß peptides. To clarify the impact of glycation on Aß aggregation, we synthesized two glycated Aß42 peptides by replacing Lys16 and Lys28 with Nε-carboxymethyllysine respectively to mimic the occurrence of protein glycation. Afterward, we monitored the aggregation kinetics and conformational change for two glycated peptides. We also used fluorescence correlation spectroscopy to probe the early stage of peptide oligomerization and tested their abilities in copper binding and reactive oxygen species production. Our data show that glycation significantly slows down the aggregation process and induces more cytotoxicity especially at position 28. We speculated that the higher toxicity might result from a relatively stable oligomeric form of peptide and not from ROS production. The data shown here emphasized that glycated proteins would be an important therapeutic target in AD treatments.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Peptídeos beta-Amiloides/metabolismo , Encéfalo , Glicosilação , Glioxal , Humanos , Fragmentos de Peptídeos/metabolismo
17.
RNA ; 27(6): 725-733, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33846273

RESUMO

The mammalian cell nucleus contains different types of membrane-less nuclear bodies (NBs) consisting of proteins and RNAs. Microscopic imaging has been widely applied to study the organization and structure of NBs. However, current fixation methods are not optimized for such imaging: When a fixation method is chosen to maximize the quality of the RNA fluorescence in situ hybridization (FISH), it often limits the labeling efficiency of proteins or affects the ultrastructure of NBs. Here, we report that addition of glyoxal (GO) into the classical paraformaldehyde (PFA) fixation step not only improves FISH signals for RNAs in NBs via augmented permeability of the fixed nucleus and enhanced accessibility of probes, but also largely preserves protein fluorescent signals during fixation and immunostaining. We also show that GO/PFA fixation enables the covisualization of different types of nuclear bodies with minimal impact on their ultrastructures under super-resolution microscopy.


Assuntos
Estruturas do Núcleo Celular/ultraestrutura , Fixadores/química , Formaldeído/química , Glioxal/química , Hibridização in Situ Fluorescente/métodos , Polímeros/química , Células HEK293 , Células HeLa , Humanos
18.
Artigo em Inglês | MEDLINE | ID: mdl-33903117

RESUMO

INTRODUCTION: Diabetes is a worldwide health problem that is associated with severe complications. Advanced Glycation End products (AGEs) such as Nε-(carboxymethyl)lysine, which result from chronic hyperglycemia, accumulate in the skin of patients with diabetes. The effect of AGEs on fibroblast functionality and their impact on wound healing are still poorly understood. RESEARCH DESIGN AND METHODS: To investigate this, we treated cultured human fibroblasts with 0.6 mM glyoxal to induce acute glycation. The behavior of fibroblasts was analyzed by time-lapse monolayer wounding healing assay, seahorse technology and atomic force microscopy. Production of extracellular matrix was studied by transmission electronic microscopy and western blot. Lipid metabolism was investigated by staining of lipid droplets (LDs) with BODIPY 493/503. RESULTS: We found that the proliferative and migratory capacities of the cells were greatly reduced by glycation, which could be explained by an increase in fibroblast tensile strength. Measurement of the cellular energy balance did not indicate that there was a change in the rate of oxygen consumption of the fibroblasts. Assessment of collagen I revealed that glyoxal did not influence type I collagen secretion although it did disrupt collagen I maturation and it prevented its deposition in the extracellular matrix. We noted a pronounced increase in the number of LDs after glyoxal treatment. AMPK phosphorylation was reduced by glyoxal treatment but it was not responsible for the accumulation of LDs. CONCLUSION: Glyoxal promotes a change in fibroblast behavior in favor of lipogenic activity that could be involved in delaying wound healing.


Assuntos
Produtos Finais de Glicação Avançada , Glioxal , Fibroblastos , Humanos , Pele , Cicatrização
19.
J Agric Food Chem ; 69(17): 5167-5177, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33891395

RESUMO

The effect of additional dl-methionine (Met) on the thermal degradation of a methionine-glucose-derived Amadori rearrangement product (MG-ARP) was investigated under different reaction conditions. The resulting color formation and changes in the concentrations of MG-ARP, Met, and α-dicarbonyl compounds were investigated. Additional Met did not affect the degradation rate of MG-ARP but got involved in subsequent reactions and resulted in a decrease in the contents of C6-α-dicarbonyl compounds. During MG-ARP degradation, the formation of glyoxal (GO) and methylglyoxal (MGO) was facilitated by additional Met, through retro-aldolization reaction of C6-α-dicarbonyl compounds. This effect of Met addition was dependent on the reaction temperature, and the consistent conclusion could be made in a buffer system. The improvement of GO and MGO formation as color precursors caused by the additional Met contributed to the acceleration of browning formation.


Assuntos
Reação de Maillard , Metionina , Glucose , Glioxal , Aldeído Pirúvico
20.
Environ Sci Technol ; 55(9): 5711-5720, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33861585

RESUMO

Particulate nitrate photolysis can produce oxidants (i.e., OH, NO2, and NO2-/HNO2) in aqueous droplets and may play a potential role in increased atmospheric oxidative capacity. Our earlier works have reported on the SO2 oxidation promoted by nitrate photolysis to produce sulfate. Here, we used glyoxal as a model precursor to examine the role of particulate nitrate photolysis in the formation of secondary organic aerosol (SOA) from particle-phase oxidation of glyoxal by OH radicals. Particles containing sodium nitrate and glyoxal were irradiated at 300 nm. Interestingly, typical oxidation products of oxalic acid, glyoxylic acid, and higher-molecular-weight products reported in the literature were not found in the photooxidation process of glyoxal during nitrate photolysis in the particle phase. Instead, formic acid/formate production was found as the main oxidation product. At glyoxal concentration higher than 3 M, we found that the formic acid/formate production rate increases significantly with increasing glyoxal concentration. Such results suggest that oxidation of glyoxal at high concentrations by OH radicals produced from nitrate photolysis in aqueous particles may not contribute significantly to SOA formation since formic acid is a volatile species. Furthermore, recent predictions of formic acid/formate concentration from the most advanced chemical models are lower than ambient observations at both the ground level and high altitude. The present study reveals a new insight into the production of formic acid/formate as well as a sink of glyoxal in the atmosphere, which may partially narrow the gap between model predictions and field measurements in both species.


Assuntos
Glioxal , Nitratos , Aerossóis , Formiatos , Fotólise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...