Une alimentation HP permet une importante diminution de la prise alimentaire, chez l’Homme et l’animal, par rapport à une alimentation STD. Les précédents travaux du laboratoire montrent que le mécanisme d’action des protéines implique une induction de la PIG chez le rat en période post-absorptive. Ce glucose, libéré et détecté dans la veine porte, permet l’activation de noyaux hypothalamiques impliqués dans la régulation des sensations de satiété. L’objectif de ce travail consistait à mettre en évidence le type de peptides pouvant induire la PIG en régime HP et d’essayer de découvrir leur mécanisme d’action. L’activité de la Glc6Pase et de l’expression des protéines Glc6Pase et PEPCK ont été quantifiées chez des rats nourris en régime STD ou HP et perfusés avec des perfusions d’acides aminés, de peptides µ-opioïdes et des solutions de di- ou tri-peptides. Les résultats montrent que le même mécanisme d’action est utilisé par les protéines et les antagonistes µ-opioïdes pour induire la PIG. Des expériences de dénervation portale et une étude immunohistochimique ont démontré la présence de récepteurs µ-opioïdes dans la veine porte probablement impliqués dans cette induction. Des perfusions de di ou tri-peptides chez le rat ont démontré que la PIG était induite par tous les di ou tri-peptides testés. L’étude phénotypique de la souris KO µ-opioïde nourrie en régime STD, HP ou ayant subi des perfusions portales de di ou tri-peptides, ont confirmé que la PIG pouvait être induite par des di ou tri-peptides et que leur mécanisme d’action nécessitait la présence de récepteurs µ-opioïdes. Cette étude suggère que tous les di- ou tri-peptides produits par la dégradation des protéines pourraient induire la PIG par un mécanisme dépendant des récepteurs µ-opioïdes / Protein feeding promotes an important decrease of food intake in humans and animals, compared on chow diet. Previous data show that this mechanism implicates intestinal glucose production (IPG) induction in rat during the post-absorptive time. Glucose released and detected into the portal vein produces an activation of hypothalamic nuclei implicated in the regulation of satiety sensations. The aim of this study was to highlight peptides which could induce IPG on HP diet and try to discoverer them mechanism. Quantification of Glc6Pase and protein expression of Glc6Pase and PEPCK were assessed in rats fed on chow or HP diet and infused with amino acids, µ-opioïd peptides and di- or tri-peptides. Our results show that the same mechanism is shared by both proteins and µ-opioïd antagonists to induce IGP. Experiments of portal vein denervation and an immunochemistry study showed that µ-opioïd receptors are present in the portal vein, probably implicated in this induction. Di or tri-peptides infusions in rat exhibited that the IGP was induced by all tested di or tri-peptides. Phenotypic study of µ-opioid mice fed on chow, HP diet or having undergone portal vein infusions of di or tri-peptides, confirmed that IGP could be induced by di or tri-peptides and their mechanism takes place with µ-opioïd receptors. This study suggests that all di or tri-peptide produced by protein degradation could induce IGP by a µ-opioïd receptor-dependent mechanism

Pregnancy loss remains a major source of economic cost to the equine industry. Frequently, the exact causes of pregnancy loss remain unknown. It has been shown, in other species, that increased dietary protein leading to elevated blood urea nitrogen concentrations (BUN) can be a factor in decreased survival of the early embryo. Our studies provided novel information regarding the effects of elevated BUN on endometrium and embryos from mares as well as insights on changes in their gene expression. Our first objective was to develop an experimental model to elevate BUN during diestrus using intravenous urea infusion. We analyzed the effects of an acute elevation in BUN on uterine and vaginal pH along with changes in the endometrial transcriptome of mares with RNA sequencing. There was a significant increase in BUN and a decrease in uterine pH in the urea group compared to the control group. A total of 193 genes were differentially expressed (DEG) between the urea and control groups. The DEG were predicted to be related to cell pH, ion homeostasis, changes in epithelial tissue, fatty acid metabolism, and solute carriers. Our second objective was to evaluate the effects of elevated BUN in the endometrium of mares using a chronic oral urea administration to elevate BUN in mares. Uterine and vaginal pH were evaluated and RNA sequencing of the endometrium was again performed. There was an increase in BUN in the urea-fed mares, but no significant change in uterine or vaginal pH between the groups. A total of 60 DEG were characterized, with prediction of transcriptomic changes in the endometrium of mares related to cell death (necrosis) and cellular movement (invasion of cells). Our third objective was to determine the effects of a high BUN on the transcriptome of day-14 embryos. There was a positive correlation between plasma BUN and blastocoele fluid urea nitrogen concentration. Changes in embryo transcriptome were related to survival of organism, angiogenesis, adhesion, and quantity of cells. Our final objective was to evaluate the correlation between BUN and follicular fluid urea nitrogen and evaluate the survival of embryos collected from donor mares with high BUN concentrations. Urea nitrogen concentration was positively correlated between the plasma and follicular fluid of mares. Additionally, there was a higher pregnancy rate when embryos were collected from mares with lower BUN. Overall, these results further elucidate the mechanisms through which urea affects endometrial and embryonic transcriptome of mares with high BUN, serving to identify effects of a high BUN in the reproductive tract of mares that might lead to decreased fertility.

It has been suggested that high protein diets are associated with an increased risk of colorectal cancer due to the higher content of red meat. However, the study of the overall dietary and lifestyle pattern may prove more important than any individual component when assessing colorectal cancer risk. From this, it is proposed that a dietary pattern used for weight loss that is higher in protein but remains low in fat and high in foods rich in fibre and micronutrients that are required for genome stability may not increase the risk of colorectal cancer, thus providing a safe and effective dietary method of weight loss in overweight subjects. This thesis describes the development of a novel in vitro faecal water genotoxicity test using the cytokinesis-block micronucleus (CBMN) cytome assay in the WIL2-NS cell line. This thesis then investigates faecal water genotoxicity and peripheral blood lymphocyte genome stability in overweight men following a weight loss dietary pattern either high in protein, specifically red meat, or high in carbohydrate. Results from this thesis indicate that the genotoxic potential of faecal water can be successfully assessed in vitro using the CBMN cytome assay. A high protein-high red meat weight loss diet did not increase faecal water genotoxicity or peripheral blood lymphocyte DNA damage, measured with the CBMN cytome assay, differently to a high carbohydrate weight loss diet. Faecal water genotoxicity data suggests weight loss and/or caloric restriction following either a high protein or high carbohydrate diet may beneficially modify the carcinogenic load of the colon in the short term, however this needs to be validated in a study that includes a non-weight loss control group. A lack of relationship was seen between faecal water genotoxicity and genome damage in lymphocytes which may suggest that the assessment of both the genome damage potential of the bowel contents and the assessment of the genome stability profile of peripheral blood lymphocytes may be important in comprehensively assessing the impact on genome damage by different dietary patterns. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1316889 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008

Thesis (Ph.D.)--Baylor University, 2008. / Includes bibliographical references (p. 161-180)

Introdução: Artrite reumatoide é uma doença inflamatória crônica associada a alterações no metabolismo proteico e energético. Objetivos: Investigar a preferência alimentar durante o desenvolvimento da inflamação crônica em ratas com artrite induzida por colágeno. Métodos: Ratas Wistar fêmeas foram alocadas em dois grupos: controle (CO, n=10) e artrite induzida por colágeno (CIA; n=11) e expostas simultaneamente a quatro diferentes dietas (padrão, hipercalórica, hiperlipidica e hiperproteica). Durante o período experimental foi observado dados clínicos da doença, consumo alimentar, peso corporal e parâmetros bioquímicos, bem como, peso muscular esquelético ao final do experimento. Os testes estatísticos realizados foram ANOVA de duas vias e test-t e nível de significância estabelecido para estes testes foi de 95%. Resultados: Os animais com artrite induzida demostram redução voluntária da ingestão total de alimento, redução do peso corporal e redução da relação sarcossomática quando comparados aos animais controles. Ainda, o grupo artrite aumentou o relativo consumo de dieta hiperproteíca, diminuiu as concentrações séricas de creatinina, triglicerídeos e glicose. Conclusão: Condições inflamatórias crônicas como a artrite reumatoide causam alterações no metabolismo energético e proteíco e estas alterações fisiológicas podem induzir a uma mudança na escolha alimentar. / Background: Rheumatoid arthritis is a chronic inflammatory disease associated with changes in energy and protein metabolism. Objective: To investigate food preferences during the development of chronic inflammation in rats with collagen-induced arthritis (CIA). Methods: Female Wistar rats were separated into two groups, control (CO, n=10) and CIA (n=11), and were simultaneously exposed to four different diets (standard, hypercaloric, hyperlipidic and hyperproteic). During the experimental period was observed clinical evidence of disease, food intake, body weight and biochemical parameters, as well as skeletal muscle weight at the end of the experiment. Statistical tests were two-away ANOVA and t-test and significance level for these tests was 95%. Results: CIA animals demonstrate voluntary reduction in total food intake, reduced body weight and reduced relative muscle weight compared to CO animals. In addition, CIA animals increased relative comsuption of high protein diet, decreased serum concentrations creatinine, triglycerides and glucose. Conclusion: Chronic inflammatory conditions such as rheumatoid arthritis cause changes in protein and energy metabolism, and these physiological alterations may induce a change in food choice.

Introdução: Artrite reumatoide é uma doença inflamatória crônica associada a alterações no metabolismo proteico e energético. Objetivos: Investigar a preferência alimentar durante o desenvolvimento da inflamação crônica em ratas com artrite induzida por colágeno. Métodos: Ratas Wistar fêmeas foram alocadas em dois grupos: controle (CO, n=10) e artrite induzida por colágeno (CIA; n=11) e expostas simultaneamente a quatro diferentes dietas (padrão, hipercalórica, hiperlipidica e hiperproteica). Durante o período experimental foi observado dados clínicos da doença, consumo alimentar, peso corporal e parâmetros bioquímicos, bem como, peso muscular esquelético ao final do experimento. Os testes estatísticos realizados foram ANOVA de duas vias e test-t e nível de significância estabelecido para estes testes foi de 95%. Resultados: Os animais com artrite induzida demostram redução voluntária da ingestão total de alimento, redução do peso corporal e redução da relação sarcossomática quando comparados aos animais controles. Ainda, o grupo artrite aumentou o relativo consumo de dieta hiperproteíca, diminuiu as concentrações séricas de creatinina, triglicerídeos e glicose. Conclusão: Condições inflamatórias crônicas como a artrite reumatoide causam alterações no metabolismo energético e proteíco e estas alterações fisiológicas podem induzir a uma mudança na escolha alimentar. / Background: Rheumatoid arthritis is a chronic inflammatory disease associated with changes in energy and protein metabolism. Objective: To investigate food preferences during the development of chronic inflammation in rats with collagen-induced arthritis (CIA). Methods: Female Wistar rats were separated into two groups, control (CO, n=10) and CIA (n=11), and were simultaneously exposed to four different diets (standard, hypercaloric, hyperlipidic and hyperproteic). During the experimental period was observed clinical evidence of disease, food intake, body weight and biochemical parameters, as well as skeletal muscle weight at the end of the experiment. Statistical tests were two-away ANOVA and t-test and significance level for these tests was 95%. Results: CIA animals demonstrate voluntary reduction in total food intake, reduced body weight and reduced relative muscle weight compared to CO animals. In addition, CIA animals increased relative comsuption of high protein diet, decreased serum concentrations creatinine, triglycerides and glucose. Conclusion: Chronic inflammatory conditions such as rheumatoid arthritis cause changes in protein and energy metabolism, and these physiological alterations may induce a change in food choice.

Introdução: Artrite reumatoide é uma doença inflamatória crônica associada a alterações no metabolismo proteico e energético. Objetivos: Investigar a preferência alimentar durante o desenvolvimento da inflamação crônica em ratas com artrite induzida por colágeno. Métodos: Ratas Wistar fêmeas foram alocadas em dois grupos: controle (CO, n=10) e artrite induzida por colágeno (CIA; n=11) e expostas simultaneamente a quatro diferentes dietas (padrão, hipercalórica, hiperlipidica e hiperproteica). Durante o período experimental foi observado dados clínicos da doença, consumo alimentar, peso corporal e parâmetros bioquímicos, bem como, peso muscular esquelético ao final do experimento. Os testes estatísticos realizados foram ANOVA de duas vias e test-t e nível de significância estabelecido para estes testes foi de 95%. Resultados: Os animais com artrite induzida demostram redução voluntária da ingestão total de alimento, redução do peso corporal e redução da relação sarcossomática quando comparados aos animais controles. Ainda, o grupo artrite aumentou o relativo consumo de dieta hiperproteíca, diminuiu as concentrações séricas de creatinina, triglicerídeos e glicose. Conclusão: Condições inflamatórias crônicas como a artrite reumatoide causam alterações no metabolismo energético e proteíco e estas alterações fisiológicas podem induzir a uma mudança na escolha alimentar. / Background: Rheumatoid arthritis is a chronic inflammatory disease associated with changes in energy and protein metabolism. Objective: To investigate food preferences during the development of chronic inflammation in rats with collagen-induced arthritis (CIA). Methods: Female Wistar rats were separated into two groups, control (CO, n=10) and CIA (n=11), and were simultaneously exposed to four different diets (standard, hypercaloric, hyperlipidic and hyperproteic). During the experimental period was observed clinical evidence of disease, food intake, body weight and biochemical parameters, as well as skeletal muscle weight at the end of the experiment. Statistical tests were two-away ANOVA and t-test and significance level for these tests was 95%. Results: CIA animals demonstrate voluntary reduction in total food intake, reduced body weight and reduced relative muscle weight compared to CO animals. In addition, CIA animals increased relative comsuption of high protein diet, decreased serum concentrations creatinine, triglycerides and glucose. Conclusion: Chronic inflammatory conditions such as rheumatoid arthritis cause changes in protein and energy metabolism, and these physiological alterations may induce a change in food choice.

The effect of the dietary macronutrient composition on weight loss has been a controversial issue for decades. During that time, a high-protein, high-fat, and low-carbohydrate diet has been one of the more popular weight loss diets with the public. We hypothesized that a computer simulation model using STELLA software could help to better understanding the effect of the dietary macronutrient composition on weight loss. We calculated daily total oxidation instead of total energy expenditure as others have done based on the facts that carbohydrate, fat, and protein intake influence carbohydrate, fat, and protein oxidation. In order to create a simple and accurate model comparing dietary macronutrient composition effects, we eliminated exercise as a factor and focused on a sedentary population. The model was validated by five sets of published human data. Following model validation, simulations were carried out to compare the traditional high-carbohydrate diet recommended by the American Dietetic Association and two well-known high-protein diets (Atkins and the Zone diet). The results of computer simulation suggested that the lean tissue retention effect of a high-protein diet, especially with a lower-fat diet, compared with a traditional high carbohydrate diet over 6 months.

No description available.

Human health is a complex and wide-ranging subject far beyond nutrition and physical exercise. Still, these factors have a huge impact on global health by their ability to prevent diseases and thus promote health. Thus, to identify health risks and benefits, it is necessary to reveal the underlying mechanisms of nutrition and exercise, which in many cases follows a complex chain of events. As a consequence, current health research is generating massive amounts of data from anthropometric parameters, genes, proteins, small molecules (metabolites) et cetera, with the intent to understand these mechanisms. For the study of health responses, especially related to physical exercise and nutrition, alterations in small molecules (metabolites) are in most cases immediate and located close to the phenotypic level and could therefore provide early signs of metabolic imbalances. Since there are roughly as many different responses to exercise and nutrients as there are humans, this quest is highly multifaceted and will benefit from an interpretation of treatment effects on a general as well as on an individual level. This thesis involves the application of chemometric methods to the study of global metabolic reactions, i.e. metabolomics, in a strategy coined predictive metabolomics. Via the application of predictive metabolomics an extensive hypothesis-free biological interpretation has been carried out of metabolite patterns in blood, acquired using gas chromatography-mass spectrometry (GC-MS), related to physical exercise, nutrition and diet, all in the context of human health. In addition, the chemometrics methodology have computational benefits concerning the extraction of relevant information from information-rich data as well as for interpreting general treatment effects and individual responses, as exemplified throughout this work. Health concerns all lifestages, thus this thesis presents a strategic framework in combination with comprehensive interpretations of metabolite patterns throughout life. This includes a broad range of human studies revealing metabolic patterns related to the impact of physical exercise, macronutrient modulation and different fitness status in young healthy males, short and long term dietary treatments in overweight post menopausal women as well as metabolic responses related to probiotics treatment and early development in infants. As a result, the studies included in the thesis have revealed metabolic patterns potentially indicative of an anti-catabolic response to macronutrients in the early recovery phase following exercise. Moreover, moderate differences in the metabolome associated with cardiorespiratory fitness level were detected, which could be linked to variation in the inflammatory and antioxidaive defense system. This work also highlighted mechanistic information that could be connected to dietary related weight loss in overweight and obese postmenopausal women in relation to short as well as long term dietary effects based on different macronutrient compositions. Finally, alterations were observed in metabolic profiles in relation to probiotics treatment in the second half of infancy, suggesting possible health benefits of probiotics supplementation at an early age. / Embargo until 2012-06-01