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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Krüppel-Like Factor 15 Orchestrates Systemic Metabolic Homeostasis

Fan, Liyan 01 September 2021 (has links)
No description available.
12

La transplantation d’hépatocytes chez le rat Long Evans Cinnamon, modèle animal de la maladie de Wilson

Vo, Kim 11 1900 (has links)
La maladie de Wilson est une maladie héréditaire due à un déficit du transporteur du cuivre, l’ATP7B. Cette maladie se présente sous forme d’insuffisance hépatique aiguë ou chronique, pour lesquels le traitement médical actuel consiste en l’administration d’agents chélateurs, ce qui ne résulte cependant pas en une guérison complète de la maladie. La transplantation orthotopique du foie est le seul traitement définitif actuellement, avec tous les désavantages qu’elle comporte. Un traitement alternatif à cette option est donc souhaitable. Cette étude porte sur la faisabilité de la transplantation d’hépatocytes chez le modèle animal de la maladie de Wilson, le rat Long Evans Cinnamon (LEC), avec pour buts d’en déterminer la sécurité et l’efficacité tant sur le plan clinique (amélioration de la survie, prévention de l’hépatite) que pathologique. Douze rats LEC ont reçu une injection intrasplénique de 2,6 x 105 – 3,6 x 107 hépatocytes prélevés chez des rats donneurs de souche LE. Ils ont été suivis durant 6 mois puis sacrifiés. Ils ont ensuite été comparés à un groupe contrôle de douze autres rats LEC. Aucune différence significative n’a été notée au niveau du poids, du bilan hépatique et des concentrations de cuivre biliaire et hépatique. Cependant, une amélioration de l’activité oxydase de la céruloplasmine post-transplantation a été démontrée chez le groupe de rats transplantés (49,6 ± 31,5 versus 8,9 ± 11,7). Les rats transplantés ont aussi eu une amélioration sur tous les critères histologiques étudiés. Enfin, l’ARNm de l’atp7b a été retrouvé chez 58% des rats transplantés avec un taux d’expression de 11,9% ± 13,6 par rapport à un rat LE normal. L’immunohistochimie a quant à elle démontré la présence de l’atp7b chez tous les rats transplantés. Les résultats obtenus sont considérés favorables à ce traitement alternatif, et indiquent que la transplantation d’hépatocytes est une technique sécuritaire qui peut contribuer à renverser le processus pathologique en cours dans la maladie de Wilson. / Wilson’s disease (WD) is a hereditary metabolic disease caused by a deficiency of copper-transporting ATP7B, resulting in copper accumulating to toxic levels in the liver. Its manifestations range from acute or chronic hepatic insufficiency to fulminant liver failure. The mainstay of therapy is the use of chelating agents. However selected patients may also require orthotopic liver transplantation (OTL), an invasive and complex procedure with life-long implications. Hepatocyte transplantation is an appealing alternative to OLT. Its safety and efficacy were evaluated in the animal model of WD, the Long Evans Cinnamon (LEC) rat. Twelve LEC rats received an intrasplenic injection of 2,6 x 105 – 3,6 x 107 hepatocytes obtained from LE donor rats. They were followed for 6 months before sacrifice. They were then compared to a control group of twelve rats. No difference was found when comparing their weights, biochemical parameters such as liver function tests and bilirubin, as well as their biliary and hepatic copper concentrations. However, the ceruloplasmin oxydase activity was improved in the transplanted rats (49,6 ± 31,5 versus 8,9 ± 11,7). After sacrifice, histologic evaluation and demonstration of atp7b mRNA in the recipient liver were performed. There was evidence of histological improvement and atp7b mRNA was found in 58% of transplanted rats with an expression of 11,9% ± 13,6 when compared to a normal LE rat. Evidence of successful engraftment of the transplanted cells was found in every transplanted rat using the technique of immunohistochemistry. These encouraging results are in accordance with previous studies on hepatocyte transplantation in the LEC rat. Its application to the human clinical setting is the next step, as it has already been tried in other metabolic liver diseases.
13

Exploring the paradox: double burden of malnutrition in rural South Africa

Kimani, Elizabeth Wambui 09 March 2011 (has links)
PhD, Faculty of Health Sciences, University of the Witwatersrand / Background: In low- to middle-income countries, rising levels of overweight and obesity are a result of multiple transitions, in particular, a nutrition transition. Consequently, in these countries, metabolic diseases are contributing increasingly to disease burden, despite the persisting burden of undernutrition and infectious diseases. Understanding the patterns and factors associated with persistent undernutrition and emerging obesity in children and adolescents, and concomitant risk for metabolic disease, is therefore of criticial importance. This should contribute to public health policy on interventions to prevent adult disease. Aims: To better understand the double burden of malnutrition in a poor, high HIV prevalent, transitional society in a middle-income country; In so doing, to inform policies and interventions to address the double burden of malnutrition. Methods: A cross-sectional growth survey was conducted in 2007 targeting 4000 children and adolescents 1-20 years of age living in rural South Africa. The survey was nested within the ongoing Agincourt Health and Socio-demographic Surveillance System, which acted as the sampling frame and also provided data for explanatory variables. Anthropometric measurements were performed on all participants using standard procedures. In addition, HIV testing was done on children aged 1 to 5 years and Tanner pubertal assessment was conducted among adolescents 9-20 years. A one-year follow-up of HIV positive children included a matched control group of HIV negative counterparts. Data collection involved both quantitative and qualitative methods. Growth z-scores were used to determine stunting, underweight and wasting and were generated using the 2006 WHO growth standards for children up to five years and the 1977 NCHS/WHO reference for older children. Overweight and obesity were determined using the International Obesity Task Force cut-offs for BMI for children aged up to 17 years and adult cut offs of BMI =25 and =30 kg/m2 for overweight and obesity respectively for adolescents 18 to 20 years. Waist circumference cut-offs of =94cm for males and =80cm for females, and waist-to-height ratio of 0.5 for both sexes, were used to determine central obesity and hence metabolic disease risk in ix adolescents. Descriptive analysis described patterns of nutritional status by age, sex, pubertal stage and HIV status. Linear and logistic regression was done to determine predictors of nutrional outcomes. A p-value of <0.05 was considered statistically significant. Results: Prevalence of undernutrition, particularly stunting, was substantial: 18% among children aged 1-4 years, with a peak of 32% in children at one year of age. Stunting and underweight were also substantial in adolescent boys, with underweight reaching a peak of 19% at 14 years of age. Concurrently, the prevalence of combined overweight and obesity, almost non-existent in boys, was prominent among adolescent girls, increasing with age, and reaching a peak of 25% at 18 years. Risk for metabolic disease using waist circumference cut-offs was substantial among adolescents, particularly girls, increasing with sexual maturation, and reaching a peak of 35% at Tanner stage 5. Prevalence of HIV in children aged 1-4 years was 4.4%. HIV positive children had poorer nutritional outcomes than that of HIV negative children in 2007. The impact of paediatric HIV on nutritional status at community level was, however, not significant. Significant predictors of undernutrition in children aged 1-4 years, documented at child, maternal, household and community levels, included child’s HIV status, age and birth weight; maternal age; age of household head; and area of residence. Significant predictors of overweight/obesity and risk for metabolic disease in adolescents aged 10-20 years, documented at individual/child and household levels included child’s age, sex and pubertal development; and household-level food security, socio-economic status, and household head’s highest education level. There was a high acceptance rate for the HIV test (95%). One year following the test, almost all caregivers had accepted and valued knowing their child’s HIV status, indicating that it enhanced their competency in caregiving. Additionally, nutritional status of HIV positive children had improved significantly within a year of follow-up. Conclusions: The study describes co-existing child stunting and adolescent overweight/obesity and risk for metabolic disease in a society undergoing nutrition transition. While likely that this profile reflects changes in nutrition and diet, variation in infectious disease burden, physical activity patterns, and social influences need to be investigated. The findings are critical in the wake of the rising public health importance of metabolic diseases in low- to middle-income countries, despite the unfinished agenda of undernutrition and infectious diseases. Clearly, policies and interventions to address malnutrition in this and other transitional societies need to be double-pronged. In addition, gender-biased nutritional patterns call for gender-sensitive policies and interventions. The study further documents a significant role of paediatric HIV on nutritional status, and the potential for community-based paediatic HIV testing to ameliorate this. Targeted early paediatric HIV testing of exposed or at risk children, followed by appropriate health care for infected children, may improve their nutritional status and survival.
14

Les lipides polaires laitiers modulent l’absorption lipidique et la lipémie postprandiale : conséquences métaboliques chez la souris / Milk polar lipids modulate lipid absorption and postprandial lipemia : metabolic consequences in mice

Lecomte, Manon 29 January 2016 (has links)
Les maladies métaboliques d’origine nutritionnelle sont caractérisées par un métabolisme des lipides perturbé et une inflammation métabolique. Les lipides polaires (LP) sont des agents émulsifiants utilisés dans l’industrie agroalimentaire. Le but de notre étude a été d’évaluer l’impact de l’utilisation de nouveaux LP issus du lait sur (i) la digestion et le métabolisme postprandial des lipides, et (ii) à plus long terme sur l’adiposité et l’inflammation dans le tissu adipeux (TA), en comparaison avec les LP de soja, actuellement les plus consommés.Chez la souris, les LP laitiers induisent une cinétique de lipémie postprandiale plus précoce en comparaison avec les LP de soja, associée à une augmentation de la lipolyse intestinale in vitro. De plus, les chylomicrons sécrétés durant le pic de lipémie sont plus petits avec les LP laitiers. D’autre part, la substitution d’une partie des lipides d’un régime hyper-lipidique par des LP laitiers ne modifie pas le stockage des lipides dans le foie et le TA contrairement aux LP de soja qui induisent une augmentation des lipides hépatiques, des adipocytes et des marqueurs inflammatoires dans le TA. Par ailleurs, Les LP laitiers induisent une diminution de l’expression génique de marqueurs de l’infiltration macrophagique dans le TA et du nombre de cellules à gobelet dans le côlon, suggérant une barrière intestinale renforcée.Ces travaux démontrent que les LP laitiers, par rapport aux LP de soja, stimulent la digestion des lipides et induisent une cinétique plus rapide de lipémie postprandiale. A long terme ils n’induisent pas les altérations métaboliques du TA observées en présence de LP de soja dans un régime hyper-lipidique / Metabolic diseases are characterized by an altered lipid metabolism and metabolic inflammation. Numerous food products contain polar lipid (PL) emulsifiers that could impact these risk factors. We evaluated the impact of using PL from milk (MPL) (i) acutely on lipid digestion and postprandial lipemia and (ii) in the longer term in addition to a high fat diet on adiposity and adipose tissue inflammation. We compared MPL to soybean PL (SPL) that is currently the main commercial source of PL.In mice, an emulsion stabilized by MPL results in a more rapid postprandial lipemia than an emulsion stabilized by SPL, with an early increase in lipemia and a faster clearance. Differences in lipemia can originate from differential kinetics of lipid hydrolysis in the mouse gut, as an increase intestinal TG hydrolysis is observed in vitro. Moreover, early MPL-derived chylomicrons are smaller than SPL-derived chylomicrons. In the longer term, compared with HF diet, HF-SPL diet increases hepatic lipids, white adipose tissue (WAT) mass, with larger and more numerous adipocytes and increases expression of pro-inflammatory adipokines. This is not observed with HF-MPL diet despite similar dietary intakes. HFP-MPL mice have a lower expression in WAT of marker of macrophage infiltration and more numerous goblet cells in the colon, suggesting an improved gut barrier function with this diet.Postprandial lipemia in mice can be modulated by emulsifying with MPL compared with SPL, partly through differences in chylomicron assembly, and intestinal TG hydrolysis rate. Moreover unlike SPL, MPL in a high fat diet do not induce WAT hypertrophy and inflammation
15

La transplantation d’hépatocytes chez le rat Long Evans Cinnamon, modèle animal de la maladie de Wilson

Vo, Kim 11 1900 (has links)
La maladie de Wilson est une maladie héréditaire due à un déficit du transporteur du cuivre, l’ATP7B. Cette maladie se présente sous forme d’insuffisance hépatique aiguë ou chronique, pour lesquels le traitement médical actuel consiste en l’administration d’agents chélateurs, ce qui ne résulte cependant pas en une guérison complète de la maladie. La transplantation orthotopique du foie est le seul traitement définitif actuellement, avec tous les désavantages qu’elle comporte. Un traitement alternatif à cette option est donc souhaitable. Cette étude porte sur la faisabilité de la transplantation d’hépatocytes chez le modèle animal de la maladie de Wilson, le rat Long Evans Cinnamon (LEC), avec pour buts d’en déterminer la sécurité et l’efficacité tant sur le plan clinique (amélioration de la survie, prévention de l’hépatite) que pathologique. Douze rats LEC ont reçu une injection intrasplénique de 2,6 x 105 – 3,6 x 107 hépatocytes prélevés chez des rats donneurs de souche LE. Ils ont été suivis durant 6 mois puis sacrifiés. Ils ont ensuite été comparés à un groupe contrôle de douze autres rats LEC. Aucune différence significative n’a été notée au niveau du poids, du bilan hépatique et des concentrations de cuivre biliaire et hépatique. Cependant, une amélioration de l’activité oxydase de la céruloplasmine post-transplantation a été démontrée chez le groupe de rats transplantés (49,6 ± 31,5 versus 8,9 ± 11,7). Les rats transplantés ont aussi eu une amélioration sur tous les critères histologiques étudiés. Enfin, l’ARNm de l’atp7b a été retrouvé chez 58% des rats transplantés avec un taux d’expression de 11,9% ± 13,6 par rapport à un rat LE normal. L’immunohistochimie a quant à elle démontré la présence de l’atp7b chez tous les rats transplantés. Les résultats obtenus sont considérés favorables à ce traitement alternatif, et indiquent que la transplantation d’hépatocytes est une technique sécuritaire qui peut contribuer à renverser le processus pathologique en cours dans la maladie de Wilson. / Wilson’s disease (WD) is a hereditary metabolic disease caused by a deficiency of copper-transporting ATP7B, resulting in copper accumulating to toxic levels in the liver. Its manifestations range from acute or chronic hepatic insufficiency to fulminant liver failure. The mainstay of therapy is the use of chelating agents. However selected patients may also require orthotopic liver transplantation (OTL), an invasive and complex procedure with life-long implications. Hepatocyte transplantation is an appealing alternative to OLT. Its safety and efficacy were evaluated in the animal model of WD, the Long Evans Cinnamon (LEC) rat. Twelve LEC rats received an intrasplenic injection of 2,6 x 105 – 3,6 x 107 hepatocytes obtained from LE donor rats. They were followed for 6 months before sacrifice. They were then compared to a control group of twelve rats. No difference was found when comparing their weights, biochemical parameters such as liver function tests and bilirubin, as well as their biliary and hepatic copper concentrations. However, the ceruloplasmin oxydase activity was improved in the transplanted rats (49,6 ± 31,5 versus 8,9 ± 11,7). After sacrifice, histologic evaluation and demonstration of atp7b mRNA in the recipient liver were performed. There was evidence of histological improvement and atp7b mRNA was found in 58% of transplanted rats with an expression of 11,9% ± 13,6 when compared to a normal LE rat. Evidence of successful engraftment of the transplanted cells was found in every transplanted rat using the technique of immunohistochemistry. These encouraging results are in accordance with previous studies on hepatocyte transplantation in the LEC rat. Its application to the human clinical setting is the next step, as it has already been tried in other metabolic liver diseases.
16

Purinergic Signaling and Autophagy Regulate the Secretion of High-Density Lipoprotein and Hepatic Lipase

Chatterjee, Cynthia 19 April 2013 (has links)
Dyslipidemia can be a comorbidity of both insulin-resistance and atherosclerosis. Hypertriglyceridemia is common in hyperglycemia and is associated with hypoalphalipoproteinemia (low HDL) and with altered nucleotide or purinergic signaling. We therefore hypothesized that extracellular nucleotides may affect hepatic lipoprotein metabolism. Our studies confirm this view and show that nucleotides regulate cellular proteolytic pathways in liver cells and thereby control lipoprotein secretion and their metabolism by hepatic lipase (HL). Treatment of liver cells with the nucleotide, adenosine diphosphate (ADP), stimulates VLDL-apoB100 and apoE secretion, but blocks HDL-apoA-I and HL secretion. ADP functions like a proteasomal inhibitor to block proteasomal degradation and stimulate apoB100 secretion. Blocking the proteosome is known to activate autophagic pathways. The nucleotide consequently stimulates autophagic degradation in liver cells and increases cellular levels of the autophagic proteins, LC3 and p62. Confocal studies show that ADP increases cellular LC3 levels and promotes co-localization of LC3 and apoA-I in an autophagosomal degradation compartment. ADP acts through the G-protein coupled receptor, P2Y13, to stimulate autophagy and block both HDL and HL secretion. Overexpression of P2Y13 increases cellular LC3 levels and blocks the induction of both HDL and HL secretion, while P2Y13 siRNA reduce LC3 protein levels and cause up to a ten-fold stimulation in HDL and HL secretion. P2Y13 gene expression regulates autophagy through the insulin receptor (IR-β). A reduction in P2Y13 expression increases the phosphorylation of IR-β and protein kinase B (Akt) >3-fold, while increasing P2Y13 expression inhibits the activation of IR-β and Akt. Experiments with epitope-labeled apoA-I and HL show that activation of purinergic pathways has no effect on the internalization and degradation of extracellular apoA-I and HL, which confirms the view that nucleotides primarily impact intracellular protein transport and degradation. In conclusion, elevated blood glucose levels may promote dyslipidemia by stimulating purinergic signaling through P2Y13 and IR-β and perturbing the intracellular degradation and secretion of both HDL and VLDL.
17

Efeito in vivo e in vitro do guaraná nos distúrbios metabólicos e nos biomarcadores inflamatórios associados à lipotoxicidade / The In vivo and in vitro effect of guaraná on metabolic diseases and inflammatory markers associated to lipotoxicity

Krewer, Cristina da Costa 15 March 2012 (has links)
The worldwide prevalence of obesity has increased severely in recent decades. Obese people have risk of developing insulin resistance, type 2 diabetes, dyslipidemia, cardiovascular disease, metabolic syndrome (MS) and cancer. In addition, obesity has been related to oxidative changes and a low-grade chronic inflammation that initially affects adipose tissue and later the others organs and systems. Guarana (Paullinia cupana) is a native plant from the Amazon, Brazil which has bioactive compounds that appear to act in energy metabolism, oxidative and inflammatory processes. However, epidemiological studies about guaraná consumption effect are still incipient. Thus, this study investigated the in vivo effect of habitual intake of guarana on the individuals health, observing the occurrence of obesity, type 2 diabetes and MS, as well as the markers associated with these diseases, as well as their behavior in experiments in vitro. In a first case-control study included 637 elderly were divided among those who habitually drank guaraná (GI: n = 421) and those who did not ingest the plant (NG, n = 239). The prevalence of hypertension, obesity and MS was lower in GI, than in the NG. In addition, in GI women were observed lower levels of total cholesterol, LDL-cholesterol and AOPP (products of advanced protein oxidation). The men in this group showed lower values of waist circumference. In a second study, we used an in vivo protocol for evaluation the guaraná effect on inflamatory markers levels. Peripheral blood mononuclear cells (PBMCs) were treated with and without guaraná (5 g/ml), besides glucose (15 mM) and insulin (1 mU/ml). Were also evaluates the citokyne plasma levels in subjects suplemented with guaraná (90 mg/day) for 14 days. Both the in vitro and in vivo analyses demonstrated a decrease in the proinflammatory cytokines: IL-1β, IL-6, TNF-, IFN- and an increase in antiinflammatory IL-10. The results demonstrate the protective guaraná effect against obesity, hypertension and MS, as well as his performance on the oxidative and inflammatory processes associated with these. / A prevalência mundial da obesidade tem aumentado consideravelmente, nas últimas décadas. Os indivíduos obesos apresentam riscos de desenvolvimento de resistência à insulina, diabetes tipo 2, dislipidemia, doenças cardiovasculares, síndrome metabólica (SM) e câncer. Além disso, a obesidade tem sido relacionada a alterações oxidativas e a uma inflamação crônica de baixo grau que atinge inicialmente o tecido adiposo e posteriormente o organismo de forma sistêmica. O guaraná (Paullinia cupana) é uma planta nativa da Amazônia, que possui compostos bioativos que parecem atuar no metabolismo energético, oxidativo e inflamatório. Entretanto, estudos epidemiológicos sobre as consequências do seu consumo na saúde humana são ainda incipientes. Sendo assim, este trabalho avaliou o efeito in vivo da ingestão habitual de guaraná pelos indivíduos testados, observando a ocorrência de obesidade, diabetes tipo 2 e SM, bem como o comportamento in vitro dos marcadores bioquímicos e inflamatórios associados a essas doenças. Em um primeiro estudo caso-controle foram incluídos 637 idosos divididos no grupo dos que ingeriam guaraná habitualmente (GI: n = 421) e dos que não ingeriam a planta (NG: n = 239). A prevalência de hipertensão, obesidade e SM foi menor no grupo GI do que no NG. Além disso, nas mulheres foram observados níveis mais baixos de colesterol total, LDL-colesterol e AOPP (produtos de oxidação proteica avançada) no grupo GI. Já os homens desse grupo mostraram menores valores de circunferência abdominal. Em um segundo estudo, foi utilizado um protocolo in vitro para avaliação do efeito do guaraná nos níveis de marcadores inflamatórios. Células mononucleares periféricas (PBMCs) foram tratadas com e sem guaraná (5 g/ml), além de glicose (15 mM) e insulina (1 mU/mL). Foram avaliados ainda, in vivo, os níveis plasmáticos de citocinas em indivíduos saudáveis suplementados com guaraná (90 mg/dia) durante 14 dias. Tanto no ensaio in vitro, como no in vivo foi observada uma diminuição nos níveis das citocinas pró-inflamatórias: IL-1β, IL-6, TNF- e IFN- e aumento da anti-inflamatória IL-10. Os resultados deste trabalho demonstram o efeito protetor do guaraná contra a obesidade, hipertensão e SM, bem como sua atuação nas rotas oxidativas e inflamatórias associadas a esses processos.
18

Purinergic Signaling and Autophagy Regulate the Secretion of High-Density Lipoprotein and Hepatic Lipase

Chatterjee, Cynthia January 2013 (has links)
Dyslipidemia can be a comorbidity of both insulin-resistance and atherosclerosis. Hypertriglyceridemia is common in hyperglycemia and is associated with hypoalphalipoproteinemia (low HDL) and with altered nucleotide or purinergic signaling. We therefore hypothesized that extracellular nucleotides may affect hepatic lipoprotein metabolism. Our studies confirm this view and show that nucleotides regulate cellular proteolytic pathways in liver cells and thereby control lipoprotein secretion and their metabolism by hepatic lipase (HL). Treatment of liver cells with the nucleotide, adenosine diphosphate (ADP), stimulates VLDL-apoB100 and apoE secretion, but blocks HDL-apoA-I and HL secretion. ADP functions like a proteasomal inhibitor to block proteasomal degradation and stimulate apoB100 secretion. Blocking the proteosome is known to activate autophagic pathways. The nucleotide consequently stimulates autophagic degradation in liver cells and increases cellular levels of the autophagic proteins, LC3 and p62. Confocal studies show that ADP increases cellular LC3 levels and promotes co-localization of LC3 and apoA-I in an autophagosomal degradation compartment. ADP acts through the G-protein coupled receptor, P2Y13, to stimulate autophagy and block both HDL and HL secretion. Overexpression of P2Y13 increases cellular LC3 levels and blocks the induction of both HDL and HL secretion, while P2Y13 siRNA reduce LC3 protein levels and cause up to a ten-fold stimulation in HDL and HL secretion. P2Y13 gene expression regulates autophagy through the insulin receptor (IR-β). A reduction in P2Y13 expression increases the phosphorylation of IR-β and protein kinase B (Akt) >3-fold, while increasing P2Y13 expression inhibits the activation of IR-β and Akt. Experiments with epitope-labeled apoA-I and HL show that activation of purinergic pathways has no effect on the internalization and degradation of extracellular apoA-I and HL, which confirms the view that nucleotides primarily impact intracellular protein transport and degradation. In conclusion, elevated blood glucose levels may promote dyslipidemia by stimulating purinergic signaling through P2Y13 and IR-β and perturbing the intracellular degradation and secretion of both HDL and VLDL.
19

Gut Microbiome, Intestinal Permeability, and Tissue Bacteria in Metabolic Disease: Perpetrators or Bystanders?

Chakaroun, Rima M., Massier, Lucas, Kovacs, Peter 20 April 2023 (has links)
The emerging evidence on the interconnectedness between the gut microbiome and host metabolism has led to a paradigm shift in the study of metabolic diseases such as obesity and type 2 diabetes with implications on both underlying pathophysiology and potential treatment. Mounting preclinical and clinical evidence of gut microbiota shifts, increased intestinal permeability in metabolic disease, and the critical positioning of the intestinal barrier at the interface between environment and internal milieu have led to the rekindling of the “leaky gut” concept. Although increased circulation of surrogate markers and directly measurable intestinal permeability have been linked to increased systemic inflammation in metabolic disease, mechanistic models behind this phenomenon are underdeveloped. Given repeated observations of microorganisms in several tissues with congruent phylogenetic findings, we review current evidence on these unanticipated niches, focusing specifically on the interaction between gut permeability and intestinal as well as extra-intestinal bacteria and their joint contributions to systemic inflammation and metabolism. We further address limitations of current studies and suggest strategies drawing on standard techniques for permeability measurement, recent advancements in microbial culture independent techniques and computational methodologies to robustly develop these concepts, which may be of considerable value for the development of prevention and treatment strategies.
20

Transcriptome Analyses of Adipose Tissue Samples Identify EGFL6 as a Candidate Gene Involved in Obesity-Related Adipose Tissue Dysfunction in Children

Landgraf, Kathrin, Kühnapfel, Andreas, Schlanstein, Maria, Biemann, Ronald, Isermann, Berend, Kempf, Elena, Kirsten, Holger, Scholz, Markus, Körner, Antje 16 January 2024 (has links)
Obesity develops early in childhood and is accompanied by early signs of adipose tissue (AT) dysfunction and metabolic disease in children. In order to analyse the molecular processes during obesity-related AT accumulation in children, we investigated genome-wide expression profiles in AT samples, isolated adipocytes, and stromal vascular fraction (SVF) cells and assessed their relation to obesity as well as biological and functional AT parameters. We detected alterations in gene expression associated with obesity and related parameters, i.e., BMI SDS, adipocyte size, macrophage infiltration, adiponectin, and/or leptin. While differential gene expression in AT and adipocytes shared an enrichment in metabolic pathways and pathways related to extracellular structural organisation, SVF cells showed an overrepresentation in inflammatory pathways. In adipocytes, we found the strongest positive association for epidermal growth factor-like protein 6 (EGFL6) with adipocyte hypertrophy. EGFL6 was also upregulated during in vitro adipocyte differentiation. In children, EGFL6 expression was positively correlated to parameters of AT dysfunction and metabolic disease such as macrophage infiltration into AT, hs-CRP, leptin levels, and HOMA-IR. In conclusion, we provide evidence for early alterations in AT gene expression related to AT dysfunction in children and identified EGFL6 as potentially being involved in processes underlying the pathogenesis of metabolic disease.

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