Formation of advanced glycation endproducts (AGEs) on proteins has been linked to the pathogenesis of diabetic complications. Importantly, elevated levels of methylglyoxal (MG) occur in type 2 diabetes mellitus (T2DM), and the resulting site-specific formation of stable adducts on arginine residues can cause protein damage. Using MG, site-specific modifications on the plasma protein plasminogen (Pg) were determined following protein digestion into peptides and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis, and 30 arginine sites were identified on the protein. Investigation into three of the most highly modified sites, R504, R530, and R561, using molecular modeling, identified likely functional changes to the Pg cleavage and the lysine binding pocket as a result of adduct formation at these sites. Overall functional changes to Pg were examined using silver staining and kinetic assays to examine normal protein cleavage by activator enzymes streptokinase (STK), tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA). MG-modified Pg exhibited decreased activation into plasmin (Pn), which is the active enzyme that forms via normal Pg cleavage, by all three activator enzymes. Activation into Pn by STK was significantly delayed by MG modification on plasminogen. Similar effects were observed with tPA and uPA. Efforts to identify the primary sites of MG adduction on Pg by two dimensional gel electrophoresis (2DGE) identified six sites, including R504 and R530, as the earliest modified sites. In order to probe MG site specific modification effects on lysine binding, MG-modified protein was run through a lysine-sepharose binding column and fractions were collected. The results indicated that MG-modified Pg bound more weakly to the column and eluted easier than unmodified Pg and LC-MS/MS using a LTQ Orbitrap Velos of the fraction indicated that R504 and R530 were the primary sites of MG adduction within the eluate. To assess MG-modification of Pg in humans, 12 plasma samples were immunodepleted of the top 14 abundant proteins and samples were analyzed by LC-MS/MS using a LTQ Orbitrap Velos. Nine of the 12 patient samples indicated the presence of MG-modified peptides. The antihyperglycemic drug metformin, a drug that scavenges MG and lowers formation of AGEs, was studied in order to better elucidate this scavenging mechanism. A novel reaction imidazolinone product, IMZ, was determined to be the primary product formed in the reaction between metformin and MG, confirmed unequivocally through x-ray diffraction analysis. In order to determine levels of IMZ in human patients on metformin therapy, multiple reaction monitoring (MRM) was employed to quantify the compound. Human urine samples from 92 patients on metformin treatment were analyzed. 66 of the 68 patients to exhibit high concentrations of metformin also indicated the presence of IMZ in their urine. The remaining samples either exhibited no metformin, or levels of metformin too low to detect the presence of IMZ. Importantly, IMZ was never identified in patients without a metformin signal, indicating the validity and quality of the assay. This dissertation builds upon the current knowledge of site-specific MG modifications, both in vitro, identifying for the first time Pg as a sensitive site-specific target of glycation, with functional effects, and importantly in humans, as this is the first identification of MG-modified Pg in vivo. The functional effects associated with this modification may provide a link between elevated MG in T2DM, and resulting cardiovascular complications. Additionally, the identification of the novel reaction product IMZ is important, as it helps to fully elucidate the role metformin plays in treating T2DM patients. The detection of IMZ in the urine of human patients on metformin therapy indicates that metformin plays a role in the reducing MG levels through scavenging in vivo, and the developed MRM method allows for future rapid, sensitive study of cohorts to better understand this mechanism and the role it plays in reducing AGEs and diabetic complications.

La vitamine C est un antioxydant connu et elle est utilisée comme supplément alimentaire et agent de conservation. Le déshydroascorbate (DHA) est une forme oxydée de la vitamine C. Chez l'humain, la plupart du DHA formé est rapidement retransformé en vitamine C par différentes voies enzymatiques. Toutefois, la dégradation du DHA mène à la formation de produits carbonylés réactifs (C=0) qui sont à leur tour impliqués dans la formation de produits de glycation avancée (AGE), entre autres en situation de stress oxydatif ou lors du vieillissement. De plus, dans les cas d’urémie chronique, l’élimination des produits carbonylés réactifs est diminuée. Récemment, notre laboratoire a démontré qu’un produit de dégradation du DHA modifiait le groupement thiol du glutathion. Cela suggère que les produits carbonylés réactifs pourraient également modifier les thiols d'autres peptides et protéines. L’objectif de cette étude est de caractériser les changements engendrés par les produits de dégradation du DHA sur différents peptides et protéines en utilisant des méthodes de spectrométrie de masse combinée avec la chromatographie liquide. Afin de mieux comprendre les modifications engendrées par le DHA, nous avons utilisé la chaîne ? de l’insuline, qui possède un nombre limité de sites cibles potentiels. En incubant la chaîne ? de l’insuline avec le DHA, nous avons observé des adduits de 130 Da sur les cystéines ayant un thiol libre par analyse aux spectromètres de masse. Des études cinétiques montrent que la modification par le DHA est plus efficace à pH 2,0 qu’à pH 7,0, car l'association des thiols libres en disulfure est facilitée à pH neutre comparativement à pH acide. Nous avons ensuite confirmé le phénomène sur des protéines entières, plus précisément l’?-lactalbumine et la ?-lactoglobuline qui présentent une plus grande complexité que la chaîne ? de l'insuline et qui pourraient être une des cibles physiologiques du DHA. Dans l’ensemble, nos résultats indiquent que les produits carbonylés réactifs provenant de la dégradation du DHA sont capables de modifier les thiols de protéines complexes. En perspective, il serait intéressant d’identifier l'impact physiologique d'une telle modification dans l’homéostasie cellulaire, plus particulièrement dans les dérèglements dus au stress oxydatif. [symboles non conformes]

Methylglyoxal (MG) is a reactive dicarbonyl compound mainly formed during glucose and fructose metabolism. Diabetic patients have increased plasma levels of MG. Our laboratory has shown that treatment with MG induces insulin resistance and type II diabetes in male Sprague-Dawley rats. However, the increases in endogenous MG level attained in different organs and its contribution to the pathogenesis of diabetes following the administration of either high glucose or high fructose diet have not been addressed. The present study aims to investigate whether the harmful effects induced by increased consumption of glucose and/or fructose is linked to increased MG generation. In vitro studies have suggested that L-arginine is an effective MG scavenger. Accordingly, another goal is to determine whether L-arginine pretreatment would scavenge MG under in vivo setting and reduce the harmful effects of hyperglycemia. MG and reduced glutathione (GSH) levels were determined in plasma and urine and in different organs of male Sprague-Dawley rats after 12 weeks of treatment with either high fructose or high glucose diet. GSH plays an important role in the degradation of MG and bears an inverse relationship with the levels of MG. The key results obtained suggest that both diets significantly increased blood pressure and plasma MG levels. A high fructose but not a high glucose diet, increased the plasma total cholesterol, triglycerides levels and total cholesterol/HDL ratio in parallel with the increases in MG and GSH levels in the liver. Increased MG levels seen in both aorta and mesenteric artery induced by high glucose or fructose diet was attenuated by pretreatment with L-arginine. These findings suggest that elevated MG level induced by treatment with high carbohydrate diets in both conduit (aorta) and resistance type (mesneteric artery) vessels may be linked to endothelial dysfunction seen in hyerglycemic/diabetic states. High glucose but not high fructose diet significantly increased MG levels in the pancreas. This observation is consistent with the well-known glucotoxicity caused by hyperglycemia in the pancreas. Taken together, these data provide the first evidence that elevated MG levels in certain organs/tissues following consumption of high fructose and/or glucose diet(s) may play a critical role in contributing to the metabolic abnormalities and the endothelial dysfunction that precedes the onset of macro and microvascular complications in either hyperglycemic and/or type II diabetic states. Interestingly, quenching of elevated MG levels in tissues by pretreamtent with L-arginine overcomes MG-induced vascular damage and endothelial dysfunction caused by high fructose and high glucose diet regimens.

Pre-gestational diabetes increases the risk of congenital malformation in the offspring and both morbidity and mortality in the diabetic mother and her offspring. During pregnancy, high glucose levels act as a teratogen through several cellular and biochemical pathways and increased production of reactive oxygen species (ROS) has a central role in diabetic embryopathy. The aim of this work was to investigate the importance of genetic predisposition for congenital malformations and to study the genes involved in the teratogenic process of diabetic pregnancy. The crossbreeding of two rat strains, with both low and high incidence of diabetes-induced malformations, indicated that strain-specific maternal factors, such as disturbed serum levels of amino acids, triglycerides, and β-hydroxybutyrate, were associated with malformation. In addition, disturbed fetal expression of genes involved in ROS defense and development (Shh, Bmp4, Ret and Gdnf) in mandible and heart, and decreased activity of Gapdh and Aldose Reductase were associated with the teratogenic process, and the trans-generational heredity of the mother determined the type of malformations induced by maternal diabetes. In rat embryos, a diabetic environment in utero changed the expression of genes involved in ROS defense (Nrf2, Gpx1 and Cat), development of mandible and heart (Msx2, Shh, Bmp4, Ret and Gdnf), and neural tube closure and apoptosis (Pax3 and p53). The changes were divergent with tissue-specific alterations of gene expression in developing mandible, heart anlage, and whole embryo. Disruption of the Receptor for Advanced Glycation End products (RAGE) had a protective effect against diabetic embryopathy in mice, and the blockage of RAGE diminished ROS production in the offspring: this supported oxidative stress being a necessary etiological component in diabetic embryopathy. Maternal metabolic state and genetic susceptibility influence fetal outcome in experimental diabetic pregnancy. Disturbed protection against oxidative stress and tissue-specific derangements in the expression of developmental genes play pivotal roles in the teratogenic mechanism, and enhanced levels of Advanced Glycation End products (AGE) and RAGE-induced oxidative stress are involved in diabetic dysmorphogenesis.

AGEs (advanced glycation end products) are end products of aminocarbonilics interactions exogenous sources whose main foods are subjected to high temperatures and dry heat. Have antigenic properties, pro-oxidant, proinflammatory, pro-fibrotic, pro-coagulants and nephrotoxic. The kidney tissue becomes a particular target for their role in the clearance of these substances, and preventing the accumulation preventing sustained increase in its serum levels, which is influenced by the aging due to the decreased renal clearance naturally present in the process physiological. The renal accumulation of AGEs may result from his imprisonment by the quantitative movement, local generation of these substances, proteins involving pre-existing pathological or decrease its clearance. The presence of AGEs in normal kidneys has been associated with the appearance of histological features similar to diabetic glomerulosclerosis, with enlargement of the basement membrane, increased glomerular volume, mensangial extracellular matrix expansion, focal glomerulosclerosis and albuminuria, and stimulate inflammation, fibrosis and hypertrophy. Kidney structures susceptible to the accumulation of AGEs include basement membrane, mesangial and endothelial cells, podocytes and tubules. Antioxidant and anti-glycantion agents as vitamin thiamine may prevent exacerbated the effects of endogenous formation and accumulation of AGEs. In this assay, we investigated the effect of chronic ingestion of diet subjected to heat treatment (autoclaving at 121.5°C for 30 min) with different levels of thiamine on renal physiology in healthy adult Wistar rats. The results indicate that after six months of treatment, there were no histological changes of renal tissue or serum biochemistry between the groups. The chronic consumption of diet termolized not promote the appearance of morphological and functional changes in kidney tissue of adult rats. It is considered that the diet composition administered may have contributed to the observed result. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / AGEs (do inglês advanced glycation end products) são produtos finais de interações aminocarbonílicas cujas principais fontes exógenas são alimentos submetidos a altas temperaturas e calor seco. Apresentam propriedades antigênicas, pró-oxidantes, pró-inflamatórias, pró-fibróticas, pró-coagulantes e nefrotóxicas. O tecido renal torna-se um alvo particular por seu papel na depuração dessas substâncias, impedindo que se acumulem e evitando o aumento sustentado de seus níveis séricos, o que sofre a influência do envelhecimento, devido a diminuição da depuração renal naturalmente presente durante esse processo fisiológico. O acúmulo renal de AGEs pode resultar de seu aprisionamento quantitativo pela circulação, da geração local dessas substâncias, envolvendo proteínas pré-existentes, ou da diminuição patológica de sua depuração. A presença de AGEs em rins normais tem sido associada ao aparecimento de características histológicas semelhantes à glomerulosclerose diabética, com alargamento da membrana basal, aumento do volume glomerular, expansão da matriz mensangial extracelular, glomerulosclerose focal e albuminúria, além de estimular inflamação, fibrose e hipertrofia. As estruturas renais suscetíveis ao acúmulo de AGEs incluem membrana basal, células mesangiais e endoteliais, podócitos, e túbulos. Agentes antioxidantes e anti-glicantes como a vitamina tiamina podem prevenir os efeitos da exacerbada formação e acúmulo endógeno de AGEs. No presente protocolo experimental foi investigada a repercussão da ingestão crônica de dieta submetida a tratamento térmico (autoclavagem a 121,5°C, por 30 min) e diferentes níveis de tiamina sobre a fisiologia renal em ratos Wistar adultos saudáveis. Os resultados indicam que, após seis meses de tratamento, não foram encontradas alterações histológicas do tecido renal nem bioquímicas séricas entre os grupos estudados. O consumo crônico de dieta termolizada não promoveu o aparecimento de alterações morfo-funcionais no tecido renal de ratos adultos. Considera-se que a composição da dieta administrada tenha contribuído para o resultado observado.

AGEs, Advanced Glycation End Products, are heterogeneous compounds with pro-oxidant and pro-inflammatory properties. These compounds are formed in the body (particularly under conditions of hyperglycemia and oxidative stress) and in environment, being the diet their main source exogenous. Neutral or alkaline food, subjected heat-treated at temperatures above 100°C with low humidity, for prolonged periods had increased formation of AGEs, conditions frequently encountered in the typical Western diet, which is a source of high levels of AGEs. The heat treatment of food, in addition to form AGEs, contributes to reducing labile vitamin with anti-glycation action and essential for humans, thiamin. The chronic consumption of diet rich in AGEs and deficient in thiamin are conditions that promote oxidative stress, carbonyl stress and persisted inflammation, contributing to the aging process with the development of several chronic diseases. When absorbed, dietary AGEs are added to those produced in the body increasing your body pool, through the kidney and liver, undergo catabolism and degradation to be eliminated. In particular, the liver is the main organ of clearance and catabolism of AGEs, becoming an easy target for the damaging effects of AGEs. In cases of thiamin deficiency, the hepatocyte is more susceptible to glyoxal, a carbonyl highly reactive precursor of AGEs, and AGEs themselves, with consequent loss of glyoxal metabolism in the liver. Supplementation of thiamin results in cytoprotection, restoration of the glyoxal detoxification, reduction of lipid peroxidation and the formation of reactive oxygen species. These elements led to the investigation of the effects of chronic consumption of thermolyzed diet, experimental model of high intake of AGEs, associated with different levels of thiamin in morpho-functional aspects of liver tissue in adult rats. For this purpose, male Wistar rats, five months old, were divided into four experimental groups according to the offered diets: standard commercial diet, control (C); thermolyzed (T), standard diet autoclaved at 121.5°C for 30 min; thermolyzed with level 1 thiamin (TT1), thiamin 6 mg/kg of diet; and thermolyzed with level 2 thiamin (TT2), 120 mg thiamin/kg of diet. After 23 weeks of treatment, animals were anesthetized and proceeded to collect samples of liver and blood, to histological analysis of hepatic tissue and tests serum biochemical of hepatic function and injury. The chronic consumption of thermolyzed diet did not promote the appearance of morphological and functional alterations in adult rat blood and liver. It is possible to consider the composition of base diet used in the experiment may have contributed to the results obtained. This study draws attention to the importance of studies to clarify the involvement of different components food for the formation of AGEs in food, which contribute to the establishment of recommendations for promoting a healthy diet, contributing to the prevention chronic diseases, including those affecting the hepatic tissue. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / AGEs, do inglês Advanced Glycation End Products, são compostos heterogêneos com propriedades pró-oxidantes e pró-inflamatórias. Estes compostos são formados no organismo (especialmente em condições de hiperglicemia e estresse oxidativo) e no ambiente, sendo a dieta sua principal fonte exógena. Alimentos neutros ou alcalinos, submetidos a tratamento térmico com temperaturas superiores a 100ºC com baixa umidade, por tempo prolongado, apresentam formação aumentada de AGEs, condições encontradas com freqüência na dieta típica do ocidente, que constitui fonte de alto teor de AGEs. O tratamento térmico dos alimentos, além de formar AGEs, contribui para a redução da vitamina termolábil com ação antiglicante e essencial para seres humanos, tiamina. O consumo crônico de dieta rica em AGEs e deficiente em tiamina são condições que favorecem o estresse oxidativo, o estresse carbonílico e a inflamação persistentes, contribuindo para o processo de envelhecimento junto ao desenvolvimento de diversas doenças crônicas. Quando absorvidos, os AGEs dietéticos somam-se aos produzidos no organismo aumentando seu pool corporal, passando pelos rins e pelo fígado, sofrem catabolismo e degradação para serem eliminados. Particularmente, o fígado é o principal órgão de clearance e catabolismo de AGEs, tornando-se um alvo fácil para os efeitos prejudiciais dos AGEs. Em situações de deficiência de tiamina, o hepatócito fica mais susceptível ao glioxal, uma carbonila altamente reativa, precursora dos AGEs, e aos próprios AGEs, com conseqüente prejuízo do metabolismo do glioxal no fígado. A suplementação de tiamina resulta em citoproteção, restauração da detoxificação do glioxal, redução da peroxidação lipídica e da formação de espécies reativas de oxigênio. Esses elementos motivaram a investigação dos efeitos do consumo crônico de dieta termolizada, modelo de experimental de elevada ingestão de AGEs, associado a diferentes níveis de tiamina, em aspectos morfo-funcionais do tecido hepático em ratos adultos. Para tanto, ratos machos Wistar, de cinco meses de idade, foram subdivididos em quatro grupos experimentais, segundo as dietas oferecidas: dieta comercial padrão, controle (C); termolizada (T), dieta padrão autoclavada a 121,5ºC, por 30 min; termolizada com tiamina nível 1 (TT1), 6 mg de tiamina/Kg de dieta; e termolizada com tiamina nível 2 (TT2), 120 mg de tiamina/Kg de dieta. Após 23 semanas de tratamento, os animais foram anestesiados e se procedeu à coleta de amostras de fígado e de sangue, para análise histológica do tecido hepático e determinações bioquímicas séricas de função e lesão hepática. O consumo crônico de dieta termolizada não promoveu o aparecimento de alterações morfo-funcionais sanguíneas e hepáticas em ratos adultos. É possível considerar que a composição da dieta de base utilizada no experimento pode ter contribuído para os resultados obtidos. O presente estudo chama a atenção para a importância da realização de estudos que esclareçam a participação dos diferentes componentes alimentares para a formação de AGEs em alimentos, o que contribuiria para o estabelecimento de recomendações dirigidas para a promoção de uma alimentação saudável, concorrendo para a prevenção de doenças crônicas, incluindo as que acometem o tecido hepático.

Methylglyoxal (MG), a highly reactive dicarbonyl accumulates after myocardial infarction (MI), causing adverse remodelling and cardiac dysfunction. We hypothesized that therapy using bone marrow cells (BMCs) overexpressing glyoxalase1 (Glo1), the main enzyme that metabolizes MG, injected into mouse MI model would translate into better survival of transplanted cells and improve their therapeutic effect. We found that Glo1 expression is significantly reduced at 7 days post-MI. Glo1 BMCs exposed to MG in vitro displayed greater angiogenic potential and reduced reactive oxygen species production compared to wild type (WT) BMCs. However, in the mouse MI model, Glo1 BMCs did not improve cardiac function or vascularity or reduce scar formation compared to WT BMCs and saline treatments. In conclusion, Glo1 overexpression in BMCs does not confer superior therapeutic efficacy for treating MI under the conditions tested.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

INTRODUÇÃO Produtos intermediários da reação de Maillard e da peroxidação, como os compostos dicarbonílicos, reagem facilmente com grupamentos aminas de proteínas e ácidos nucléicos levando a modificações biológicas que podem resultar em patologias observadas no diabetes, aterosclerose e doenças neurodegenerativas. O consumo de Produtos da Reação de Maillard (PRM) aumentou nas últimas décadas e há evidências de que estas substâncias são absorvidas e podem tomar parte em processos patológicos, embora ainda não haja consenso sobre os possíveis efeitos deletério à saúde a partir do aumento de sua ingestão. Ressalta-se a necessidade de estimar o consumo destes PRMs a partir de dados sobre os conteúdos e a ingestão habitual do alimento em questão como cereais matinais e café. Objetivos: a) validar metodologia para quantificar indicadores da reação de Maillard: hidroximetilfurfural (HMF), furosina (FUR), carboximetilisina (CML) e Compostos Intermediários Fluorescentes (CIF) em cereais matinais (flocos e granola) e café; b) avaliar se há diferenças nos teores desses compostos nas diferentes marcas destes produtos comercializados em São Paulo; METODOLOGIA: Foram analisados dois lotes de três marcas de cereais do tipo flocos, três marcas de cereais do tipo granola e cinco marcas de café presentes em 100 por cento dos hipermercados visitados no município de São Paulo. A validação da metodologia para quantificação, empregando HPLC, consistiu no cálculo da exatidão (recuperação), repetibilidade e sensibilidade para os compostos: HMF e FUR. Foram determinados os teores de CIF por espectrofotometria de fluorescência e os teores de CML por teste imunoenzimático. RESULTADOS: Os métodos de determinação de FUR e HMF foram validados conforme o Instituto Nacional de Metrologia, Normalização e 9 Qualidade Industrial (INMETRO). O teor médio de CIF livre e total foram maiores para as amostras de café, com média de 232CIF/mg e 765CIF/mg respectivamente. Não houve diferença (p>0,05) no teor de CIF livre e total entre os flocos F1 e F2. O mesmo foi observado para a granola marcas. G1, G2 e G3 A granola foi o produto com maior teor médio de HMF (67,5mg/Kg) e furosina (301mg/100g de proteína). A FUR não foi detectado nas amostras de café. Todas as marcas dos alimentos estudados para os indicadores HMF e FUR apresentaram diferença estatisticamente significativa (p<0,05). O café apresentou maior teor médio de CML (1823,5ng/mg de proteína), sem diferença entre as marcas (p>0,05) CONCLUSÕES: Os cereais do tipo flocos contribuem para maior ingestão de PRMs da fase inicial da reação de Maillard (RM), a granola contribui para maior ingestão de PRMs da fase intermediária da RM e o café contribui de forma significativa para maior ingestão de PRMs da fase avançada da RM. O café, por ser submetido a tratamento térmico mais severo apresenta maior concentração de PRMs da fase avançada da reação / INTRODUCTION Maillard reaction products and lipid peroxidation, such as dicarbonyl compounds easily react with amino groups of proteins and nucleic acids leading to biological changes that can result in complications in diseases such as diabetes, atherosclerosis and neurodegenerative. The consumption of Maillard Reaction Products (MRP) has increased in recent decades and there is evidence that these substances are absorbed and can participate in pathological processes, although there is no consensus about the possible harmful health effects from their intake. We highlight the need to identify the consumption of MRP, mainly in vulnerable populations like children and diabetics, in order to establish acceptable daily intakes and guidelines for the food industry. OBJECTIVES: a) validate the methodology to measure indicators of the Maillard reaction: hydroxymethylfurfural (HMF), Furosine (RUF) carboxymethylysine (CML) and fluorescent intermediate compounds (FIC) in breakfast cereals (corn flakes and granola) and coffee, b) to evaluate if there are differences in the levels of these compounds contents among brands commercialized in São Paulo METHODS: two lots of 3 brands of flakes cereal, 3 brands of granola and 5 coffee brands present in 100 per cent of supermarkets visited in the city Sao Paulo were analyzed. HPLC methodology validation was assessed by determining accuracy (recovery), repeatability, and sensibility (linearity, limits of detection and quantitation) for the compounds: HMF and FUR. The contents of the Fluorescent Intermediary compounds (FIC) was measured by spectrophotometric method and the levels of CML by ELISA. RESULTS: Calibration curves determination coefficient (r 2) were higher than 0,99 for all compounds. Recovery ranged from 84 to 110 per cent and repeatability average was 3,5 per cent. The average content of free and total FIC was higher for coffee 232CIF/mg and 765CIF/mg respectively. The brands of granola and flakes was similar but just brands F1 and F2 was similar between brands (p<0,05). For HMF the higher values were for granola 67,5mg/kg. The presence of dried fruit in these grains may 11 have contributed significantly to the higher rate of this indicator. For indicator FUR average was higher in granola samples (301mg/100g of protein) and it was not possible to quantify the levels of FUR for coffee. All brands analyzed for HMF and FUR was similar (p<0,05). CML average was higher for coffee (1823,5ng/mg of protein). The brands analyzed was similar for all samples (p <0.05). CONCLUSIONS: Flakes contribute to higher intake of MRPs from early stage of the Maillard reaction (MR), the granola contributes to higher intake of MRPs from intermediate phase of MR and coffee contributes significantly to higher intake of final MRPs. Data suggest that coffee has more severe thermal treatment causing a higher concentration of MRPs from the final phase of the MR

Myocardial infarction (MI) persists as one of the leading causes of death worldwide. Often patients whom survive the initial injury will develop heart failure characterized by a dilated and functionally incompetent heart. Heart failure (HF) carries a worse prognosis than most cancers, and the only curative therapy to date is heart transplantation. A better understanding of the repair and remodeling processes post-MI, and the development of novel therapies are required to combat this burgeoning medical challenge. This thesis research sought to identify a novel mediator of the impaired cardiac remodeling that often occurs post-MI, and to characterize a biomaterial hydrogel therapy as a novel treatment. We investigated the role of methylglyoxal (MG), an important precursor to advanced glycation end-products (AGE), using a transgenic mouse model to over-express glyoxalase 1 (GLO1). GLO1 is the primary enzyme involved in metabolizing MG and preventing its accumulation. The role for MG and AGEs in MI and HF had been alluded to in the literature, yet no study to date has causally linked them with the loss of function and impaired remodeling of the post-MI heart. We also assessed an injectable hydrogel for the treatment of MI using a mouse model and evaluated the impact of delivery timing on its therapeutic efficacy. In this thesis, we confirmed that MG derived AGEs accumulate post-MI (Chapter 3.1). We show that preventing their accumulation, through GLO1 over-expression, mitigates the loss of function post-MI and positively influences remodeling through reducing final infarct sizes and end-systolic volumes. We demonstrate that this may possibly occur through improving the bone marrow response post-MI by restoring ECM-cell signaling. In Chapter 3.2, we present results of a study assessing the efficacy of a collagen based injectable hydrogel for the treatment of MI, and assessing the role that timing plays into the benefits associated with this therapy by studying 3 separate timepoints including 3 hours, 7 days and 14 days post-MI. We found that the injectable hydrogel preserved cardiac function and reduced infarct sizes. It also positively interacted with the host repair response by reducing chronic inflammation and cell death. The benefits of the therapy depended on when the material was delivered, and we found that the earliest timepoint (3 hours post-MI) proved most beneficial. In Chapter 3.3, we combined the knowledge gained from Chapters 3.1 and 3.2 and functionalized our hydrogel with a flavonoid, Fisetin, that has been shown to scavenge MG and increase the activity of GLO1. We show that this novel functionalized material may be able to restore some function in MI, particularly in settings of low baseline cardiac function. Taken together, the results of this thesis demonstrate that MG accumulates as a result of the ischemia and contributes to the impaired repair resolution and remodeling processes post-MI. This identifies MG as a possible novel target for the treatment of MI. Indeed, we also confirm the role that delivery timing plays into injectable hydrogels post-MI, and present promising results for a functionalized material design to intervene on MG production.