A. Geloen - Academia.edu (original) (raw)

Papers by A. Geloen

Research paper thumbnail of Impact of chemical ageing on the toxicity of biogenic and anthropogenic organic aerosols using model cells

Bookmarks Related papers MentionsView impact

Research paper thumbnail of On the Right Track, Finally?

Critical Care Medicine, 2019

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Adipocytes as lipid sensors of oleic acid transport through a functional Caco-2/HT29-MTX intestinal barrier

Adipocyte, 2019

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Decreased norepinephrine turnover rate in the brown adipose tissue of pre-obese fa/fa Zucker rats

Journal of developmental physiology, 1993

Norepinephrine (NE) content and turnover rate, and the activity of dopamine-beta-hydroxylase (DBH... more Norepinephrine (NE) content and turnover rate, and the activity of dopamine-beta-hydroxylase (DBH) were measured in the brown adipose tissue (BAT) of developing Zucker rats of the three genotypes: Fa/Fa and Fa/fa (with a lean phenotype) and fa/fa (phenotypically obese). As early as 15 days of age, namely at a pre-obese stage, BAT NE content and turnover rate are already reduced in fa/fa rats, just like they are at 50 days. The development of DBH activity is completely impaired in fa/fa rats. These results demonstrate that the reduction in sympathetic tone in BAT of fa/fa rats is already present before the onset of phenotypic obesity.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Ozone Exposure Triggers Insulin Resistance Through Muscle c-Jun N-Terminal Kinase Activation

Diabetes, 2014

A growing body of evidence suggests that exposure to traffic-related air pollution is a risk fact... more A growing body of evidence suggests that exposure to traffic-related air pollution is a risk factor for type 2 diabetes. Ozone, a major photochemical pollutant in urban areas, is negatively associated with fasting glucose and insulin levels, but most aspects of this association remain to be elucidated. Using an environmentally realistic concentration (0.8 parts per million), we demonstrated that exposure of rats to ozone induced whole-body insulin resistance and oxidative stress, with associated endoplasmic reticulum (ER) stress, c-Jun N-terminal kinase (JNK) activation, and disruption of insulin signaling in skeletal muscle. Bronchoalveolar lavage fluids from ozone-treated rats reproduced this effect in C2C12 myotubes, suggesting that toxic lung mediators were responsible for the phenotype. Pretreatment with the chemical chaperone 4-phenylbutyric acid, the JNK inhibitor SP600125, or the antioxidant N-acetylcysteine alleviated insulin resistance, demonstrating that ozone sequentiall...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Cirsimarin, a potent antilipogenic flavonoid, decreases fat deposition in mice intra-abdominal adipose tissue

International Journal of Obesity, 2010

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Periatrial Epicardial Fat Is Associated with Markers of Endothelial Dysfunction in Patients with Atrial Fibrillation

PLoS ONE, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Leptin Induces a Proliferative Response in Breast Cancer Cells but Not in Normal Breast Cells

Nutrition and Cancer, 2014

Obesity is a risk factor for breast cancer in postmenopausal women. Leptin, a hormone excessively... more Obesity is a risk factor for breast cancer in postmenopausal women. Leptin, a hormone excessively produced during obesity, is suggested to be involved in breast cancer. The aim of the study was to investigate procarcinogenic potential of leptin by evaluating influence of leptin on cell proliferation, cell cycle, apoptosis, and signaling on numerous breast cells lines, including 184B5 normal cells, MCF10A fibrocystic cells and MCF-7, MDA-MB-231, and T47D cancer cells. Expressions of leptin and Ob-R were analyzed using qRT-PCR and immunohistochemistry, proliferation using fluorimetric resazurin reduction test and xCELLigence system, apoptosis and cell cycle by flow cytometry, and effect of leptin on different signalling pathways using qRT-PCR and Western blot. Cells were exposed to increasing concentrations of leptin. All cell lines expressed mRNA and protein of leptin and Ob-R. Leptin stimulated proliferation of all cell lines except for 184B5 and MDA-MB-231 cells. Leptin inhibited apoptosis but didn't alter proportion of cells within cell cycle in MCF7 cells. Leptin induced overexpression of leptin, Ob-R, estrogen receptor, and aromatase mRNA in MCF-7 and T47D cells. Autoregulation induced by leptin, relationship with estrogen pathway, and proliferative and antiapoptic activity in breast cancer cells may explain that obesity-associated hyperleptinemia may be a breast cancer risk factor.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of PO30 Une exposition expérimentale à l’ozone génère chez le rat un stress oxydant à l’origine d’une insulino-résistance musculaire

Diabetes & Metabolism, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of O55 Pollution atmosphérique et diabète de type 2 : peut on imaginer une origine environnementale aux maladies métaboliques ?

Diabetes & Metabolism, 2011

ABSTRACT Introduction Les concentrations en ozone atteignent dans nos cités des seuils préoccupan... more ABSTRACT Introduction Les concentrations en ozone atteignent dans nos cités des seuils préoccupants pour la santé. Des résultats récents obtenus dans notre laboratoire indiquent qu’une exposition expérimentale de courte durée à l’ozone (12 heures, 0,8 ppm) est chez le rat à l’origine d’un stress oxydant systémique avéré par la mesure de plusieurs marqueurs plasmatiques (malondialdehyde, 4-hydroxy-2-nonenal, glutathion, protéines carbonylées). Ainsi, douze heures d’exposition à l’ozone induisent chez le rat un état d’intolérance au glucose qui se traduit par une incapacité à normaliser la glycémie au terme d’une « charge » expérimentale en glucose. L’ozone étant trop réactif pour traverser la barrière alvéolo-capillaire, la toxicité systémique de l’ozone résulte vraisemblablement de la production au niveau pulmonaire de produits lipidiques d’ozonation (LOPs, lipid ozonation products) qui sont suffisamment stables pour gagner la circulation sanguine et dont les effets délétères sur les tissus périphériques restent à démontrer. Les objectifs de notre étude sont 1) d’évaluer la sensibilité à l’insuline chez le rat exposé à l’ozone 2) de caractériser la production de médiateurs toxiques dans les poumons de rat exposés à l’ozone et de vérifier leur toxicité pour la glycoréglation sur des lignées de cellules musculaires (lignée C2C12). Matériels et méthodes Des rats Wistars sont exposés pendant une nuit à 0,8 ppm. Des tests de tolérance à l’insuline et un clamp euglycémique hyperinsulinique sont réalisés pour évaluer la sensibilité à l’insuline. Des myotubes C2C12 sont incubés en présence de lavages broncho-alvéolaires de rats contrôle ou ozone et la sensibilité à l’insuline est évaluée : 1) par la mesure de la capture du [3H]-2-deoxyglucose, 2) par l’étude de la phosphorylation de protéines clé de la voie de signalisation de l’insuline (PKB/Akt, IRS-1) en western blotting. Résultats Les tests de tolérance à l’insuline et de clamp ont mis en évidence le développement d’une résistance périphérique à l’insuline chez les rats exposés à l’ozone ; Le débit de perfusion de glucose nécessaire pour maintenir l’euglycémie est de 25 mg.kg-1.min-1 chez les rats contrôles et de 9 mg.kg-1.min-1 chez les rats exposés à l’ozone (N = 5, P < 0.01). Les cellules C2C12 traitées avec les lavages broncho-alvéolaires de rats exposés à l’ozone ont montré une sensibilité à l’insuline diminuée (incorporation de glucose réduite de 30 % après stimulation des cellules à l’insuline, p < 0.05). Conclusion L’ozone génère au niveau pulmonaire des médiateurs toxiques susceptibles d’induire une insulino-résistance périphérique. Ces travaux mettent en exergue un lien possible entre pollution et diabète et suggèrent le rôle de facteurs environnementaux dans l’étiologie de cette maladie pour l’heure essentiellement attribuée à des facteurs génétiques et/ou nutritionnels.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Reverse Physiology, i.e., Cellular Versus Integrative Versus Comparative Physiology? α-2 Agonists and Septic Shock

Critical care medicine, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Emulsified lipids increase endotoxemia: possible role in early postprandial low-grade inflammation

The Journal of Nutritional Biochemistry, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Food Industry and Its Response to Public Health Issues

The prevalence of childhood obesity in the US is high, currently almost 17% of children and adole... more The prevalence of childhood obesity in the US is high, currently almost 17% of children and adolescents ages 2-19 years are considered obese. Following a tripling in the prevalence of childhood obesity since 1980, the rapid increase in prevalence has slowed and possibly leveled off during the last 10 years. Childhood obesity often tracks to adulthood and, in the short run, childhood obesity can lead to psychosocial problems and cardiovascular risk factors such as high blood pressure, high cholesterol and abnormal glucose tolerance or diabetes. This session will describe the epidemiology of childhood obesity in the US.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Increased pressor response to noradrenaline during septic shock following clonidine?

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Lactate production by white adipocytes in relation to insulin sensitivity

American Journal of Physiology-Cell Physiology

Besides its lipogenic and lipolytic functions, adipose tissue has been recognized as an important... more Besides its lipogenic and lipolytic functions, adipose tissue has been recognized as an important site of lactate production by epididymal adipocytes under experimental conditions in which insulin sensitivity was increased (cold exposure) or reduced (glucose perfusion). Insulin sensitivity of adipocytes was assessed by its antilipolytic effect and its stimulation of glucose uptake. We showed that, in adipocytes isolated from control and cold-exposed animals, glycerol and lactate production rose simultaneously, in response to norepinephrine. On the other hand, in adipocytes from glucose-perfused animals, we observed a dissociation between lipolytic and glycolytic responses. Indeed, lactate production in response to norepinephrine reached 60% of maximal response (10(-7)M) while the lipolytic response was still basal. This phenomenon was the result of a desensitization of beta-adrenergic receptors. However, the sensitivity of adipocytes to stimulation of lactate production by catechola...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Cytotoxicity control of silicon nanoparticles by biopolymer coating and ultrasound irradiation for cancer theranostic applications

Nanotechnology, 2017

Silicon nanoparticles (SiNPs) prepared by mechanical grinding of luminescent porous silicon were ... more Silicon nanoparticles (SiNPs) prepared by mechanical grinding of luminescent porous silicon were coated with a biopolymer (dextran) and investigated as a potential theranostic agent for bioimaging and sonodynamic therapy. Transmission electron microscopy, photoluminescence and Raman scattering measurements of dextran-coated SiNPs gave evidence of their enhanced stability in water. In vitro experiments confirmed the lower cytotoxicity of the dextran-coated NPs in comparison with uncoated ones, especially for high concentrations of about 2 mg ml-1. Efficient uptake of the NPs by cancer cells was found using bioimaging in the optical transmittance and photoluminescence modes. Treatment of the cells with uptaken SiNPs by therapeutic ultrasound for 5-20 min resulted in a strong decrease in the number of living cells, while the total number of cells remained nearly unchanged. The obtained data indicate a 'mild' effect of the combined action of ultrasonic irradiation and SiNPs on cancer cells. The observed results reveal new opportunities for controlling the photoluminescent and sonosensitizing properties of silicon-based NPs for applications in the diagnostics and mild therapy of cancer.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Markers of vulnerable plaques in non-human primates under atherogenic diet

Atherosclerosis, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Nonlinear Optical Properties of Silicon Carbide (SiC) Nanoparticles by Carbothermal Reduction

Colloidal Nanoparticles for Biomedical Applications XI, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Milk Polar Lipids Affect In Vitro Digestive Lipolysis and Postprandial Lipid Metabolism in Mice

Journal of Nutrition, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of P174 Impact de différents lipides polaires sur l’absorption et le métabolisme des lipides: études in vitro sur cellules Caco-2 et in vivo chez la souris

Diabetes & Metabolism, 2015

Introduction Les maladies metaboliques d'origine nutritionnelle sont caracterisees par un met... more Introduction Les maladies metaboliques d'origine nutritionnelle sont caracterisees par un metabolisme des lipides perturbe incluant une hyperlipemie postprandiale. Dans ce contexte, un interet se developpe autour des effets des lipides polaires (LP), agents de texture largement utilises dans l'industrie alimentaire. Nous etudions donc l'impact de LP de differentes sources alimentaires (vegetal vs animal) sur la lipemie postprandiale. Materiels et methodes Des souris ont ete gavees avec 2 types d'emulsions, dont les gouttelettes de matiere grasse etaient recouvertes de LP laitiers ou de LP de soja. Le plasma et l'intestin grele ont ete collectes au cours de la digestion. Des cellules intestinales Caco-2/TC7 ont ete incubees 24 heures avec des micelles lipidiques contenant differents L P, phosphatidylcholine ou sphingomyeline (specifique des LP laitiers) pour analyse des chylomicrons secretes. Resultats Une heure apres gavage, les LP Laitiers induisent des concentrations plasmatiques de triglycerides et d'acides gras libres plus elevees que les LP de soja. L'effet inverse est observe apres 4 heures. Ces lipemies differentes sont associees a une moindre expression genique de proteines impliquees dans la secretion des chylomicrons, dans le duodenum du groupe LP laitiers a 4 heures. Ceci suggere que l'absorption et la metabolisation des lipides dependent du type de LP utilise, notamment via une modulation des genes dans l'enterocyte. In vitro , la presence de sphin-gomyeline dans les micelles induit une secretion plus importante de triglycerides sous la forme de plus petits chylomicrons. Ainsi, les effets observes in vivo sont probablement dus a la teneur elevee des LP laitiers en sphingomyeline. Conclusion Ces resultats suggerent que la qualite des lipides polaires utilises pour stabiliser une emulsion influence le metabolisme postprandial des lipides. Ces nouvelles connaissances pourraient servir a la mise en place de formulations alimentaires optimisees. Declaration d’interet Les auteurs declarent ne pas avoir d'interet direct ou indirect (financier ou en nature) avec un organisme prive, industriel ou commercial en relation avec le sujet presente.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Impact of chemical ageing on the toxicity of biogenic and anthropogenic organic aerosols using model cells

Bookmarks Related papers MentionsView impact

Research paper thumbnail of On the Right Track, Finally?

Critical Care Medicine, 2019

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Adipocytes as lipid sensors of oleic acid transport through a functional Caco-2/HT29-MTX intestinal barrier

Adipocyte, 2019

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Decreased norepinephrine turnover rate in the brown adipose tissue of pre-obese fa/fa Zucker rats

Journal of developmental physiology, 1993

Norepinephrine (NE) content and turnover rate, and the activity of dopamine-beta-hydroxylase (DBH... more Norepinephrine (NE) content and turnover rate, and the activity of dopamine-beta-hydroxylase (DBH) were measured in the brown adipose tissue (BAT) of developing Zucker rats of the three genotypes: Fa/Fa and Fa/fa (with a lean phenotype) and fa/fa (phenotypically obese). As early as 15 days of age, namely at a pre-obese stage, BAT NE content and turnover rate are already reduced in fa/fa rats, just like they are at 50 days. The development of DBH activity is completely impaired in fa/fa rats. These results demonstrate that the reduction in sympathetic tone in BAT of fa/fa rats is already present before the onset of phenotypic obesity.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Ozone Exposure Triggers Insulin Resistance Through Muscle c-Jun N-Terminal Kinase Activation

Diabetes, 2014

A growing body of evidence suggests that exposure to traffic-related air pollution is a risk fact... more A growing body of evidence suggests that exposure to traffic-related air pollution is a risk factor for type 2 diabetes. Ozone, a major photochemical pollutant in urban areas, is negatively associated with fasting glucose and insulin levels, but most aspects of this association remain to be elucidated. Using an environmentally realistic concentration (0.8 parts per million), we demonstrated that exposure of rats to ozone induced whole-body insulin resistance and oxidative stress, with associated endoplasmic reticulum (ER) stress, c-Jun N-terminal kinase (JNK) activation, and disruption of insulin signaling in skeletal muscle. Bronchoalveolar lavage fluids from ozone-treated rats reproduced this effect in C2C12 myotubes, suggesting that toxic lung mediators were responsible for the phenotype. Pretreatment with the chemical chaperone 4-phenylbutyric acid, the JNK inhibitor SP600125, or the antioxidant N-acetylcysteine alleviated insulin resistance, demonstrating that ozone sequentiall...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Cirsimarin, a potent antilipogenic flavonoid, decreases fat deposition in mice intra-abdominal adipose tissue

International Journal of Obesity, 2010

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Periatrial Epicardial Fat Is Associated with Markers of Endothelial Dysfunction in Patients with Atrial Fibrillation

PLoS ONE, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Leptin Induces a Proliferative Response in Breast Cancer Cells but Not in Normal Breast Cells

Nutrition and Cancer, 2014

Obesity is a risk factor for breast cancer in postmenopausal women. Leptin, a hormone excessively... more Obesity is a risk factor for breast cancer in postmenopausal women. Leptin, a hormone excessively produced during obesity, is suggested to be involved in breast cancer. The aim of the study was to investigate procarcinogenic potential of leptin by evaluating influence of leptin on cell proliferation, cell cycle, apoptosis, and signaling on numerous breast cells lines, including 184B5 normal cells, MCF10A fibrocystic cells and MCF-7, MDA-MB-231, and T47D cancer cells. Expressions of leptin and Ob-R were analyzed using qRT-PCR and immunohistochemistry, proliferation using fluorimetric resazurin reduction test and xCELLigence system, apoptosis and cell cycle by flow cytometry, and effect of leptin on different signalling pathways using qRT-PCR and Western blot. Cells were exposed to increasing concentrations of leptin. All cell lines expressed mRNA and protein of leptin and Ob-R. Leptin stimulated proliferation of all cell lines except for 184B5 and MDA-MB-231 cells. Leptin inhibited apoptosis but didn't alter proportion of cells within cell cycle in MCF7 cells. Leptin induced overexpression of leptin, Ob-R, estrogen receptor, and aromatase mRNA in MCF-7 and T47D cells. Autoregulation induced by leptin, relationship with estrogen pathway, and proliferative and antiapoptic activity in breast cancer cells may explain that obesity-associated hyperleptinemia may be a breast cancer risk factor.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of PO30 Une exposition expérimentale à l’ozone génère chez le rat un stress oxydant à l’origine d’une insulino-résistance musculaire

Diabetes & Metabolism, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of O55 Pollution atmosphérique et diabète de type 2 : peut on imaginer une origine environnementale aux maladies métaboliques ?

Diabetes & Metabolism, 2011

ABSTRACT Introduction Les concentrations en ozone atteignent dans nos cités des seuils préoccupan... more ABSTRACT Introduction Les concentrations en ozone atteignent dans nos cités des seuils préoccupants pour la santé. Des résultats récents obtenus dans notre laboratoire indiquent qu’une exposition expérimentale de courte durée à l’ozone (12 heures, 0,8 ppm) est chez le rat à l’origine d’un stress oxydant systémique avéré par la mesure de plusieurs marqueurs plasmatiques (malondialdehyde, 4-hydroxy-2-nonenal, glutathion, protéines carbonylées). Ainsi, douze heures d’exposition à l’ozone induisent chez le rat un état d’intolérance au glucose qui se traduit par une incapacité à normaliser la glycémie au terme d’une « charge » expérimentale en glucose. L’ozone étant trop réactif pour traverser la barrière alvéolo-capillaire, la toxicité systémique de l’ozone résulte vraisemblablement de la production au niveau pulmonaire de produits lipidiques d’ozonation (LOPs, lipid ozonation products) qui sont suffisamment stables pour gagner la circulation sanguine et dont les effets délétères sur les tissus périphériques restent à démontrer. Les objectifs de notre étude sont 1) d’évaluer la sensibilité à l’insuline chez le rat exposé à l’ozone 2) de caractériser la production de médiateurs toxiques dans les poumons de rat exposés à l’ozone et de vérifier leur toxicité pour la glycoréglation sur des lignées de cellules musculaires (lignée C2C12). Matériels et méthodes Des rats Wistars sont exposés pendant une nuit à 0,8 ppm. Des tests de tolérance à l’insuline et un clamp euglycémique hyperinsulinique sont réalisés pour évaluer la sensibilité à l’insuline. Des myotubes C2C12 sont incubés en présence de lavages broncho-alvéolaires de rats contrôle ou ozone et la sensibilité à l’insuline est évaluée : 1) par la mesure de la capture du [3H]-2-deoxyglucose, 2) par l’étude de la phosphorylation de protéines clé de la voie de signalisation de l’insuline (PKB/Akt, IRS-1) en western blotting. Résultats Les tests de tolérance à l’insuline et de clamp ont mis en évidence le développement d’une résistance périphérique à l’insuline chez les rats exposés à l’ozone ; Le débit de perfusion de glucose nécessaire pour maintenir l’euglycémie est de 25 mg.kg-1.min-1 chez les rats contrôles et de 9 mg.kg-1.min-1 chez les rats exposés à l’ozone (N = 5, P < 0.01). Les cellules C2C12 traitées avec les lavages broncho-alvéolaires de rats exposés à l’ozone ont montré une sensibilité à l’insuline diminuée (incorporation de glucose réduite de 30 % après stimulation des cellules à l’insuline, p < 0.05). Conclusion L’ozone génère au niveau pulmonaire des médiateurs toxiques susceptibles d’induire une insulino-résistance périphérique. Ces travaux mettent en exergue un lien possible entre pollution et diabète et suggèrent le rôle de facteurs environnementaux dans l’étiologie de cette maladie pour l’heure essentiellement attribuée à des facteurs génétiques et/ou nutritionnels.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Reverse Physiology, i.e., Cellular Versus Integrative Versus Comparative Physiology? α-2 Agonists and Septic Shock

Critical care medicine, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Emulsified lipids increase endotoxemia: possible role in early postprandial low-grade inflammation

The Journal of Nutritional Biochemistry, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The Food Industry and Its Response to Public Health Issues

The prevalence of childhood obesity in the US is high, currently almost 17% of children and adole... more The prevalence of childhood obesity in the US is high, currently almost 17% of children and adolescents ages 2-19 years are considered obese. Following a tripling in the prevalence of childhood obesity since 1980, the rapid increase in prevalence has slowed and possibly leveled off during the last 10 years. Childhood obesity often tracks to adulthood and, in the short run, childhood obesity can lead to psychosocial problems and cardiovascular risk factors such as high blood pressure, high cholesterol and abnormal glucose tolerance or diabetes. This session will describe the epidemiology of childhood obesity in the US.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Increased pressor response to noradrenaline during septic shock following clonidine?

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Lactate production by white adipocytes in relation to insulin sensitivity

American Journal of Physiology-Cell Physiology

Besides its lipogenic and lipolytic functions, adipose tissue has been recognized as an important... more Besides its lipogenic and lipolytic functions, adipose tissue has been recognized as an important site of lactate production by epididymal adipocytes under experimental conditions in which insulin sensitivity was increased (cold exposure) or reduced (glucose perfusion). Insulin sensitivity of adipocytes was assessed by its antilipolytic effect and its stimulation of glucose uptake. We showed that, in adipocytes isolated from control and cold-exposed animals, glycerol and lactate production rose simultaneously, in response to norepinephrine. On the other hand, in adipocytes from glucose-perfused animals, we observed a dissociation between lipolytic and glycolytic responses. Indeed, lactate production in response to norepinephrine reached 60% of maximal response (10(-7)M) while the lipolytic response was still basal. This phenomenon was the result of a desensitization of beta-adrenergic receptors. However, the sensitivity of adipocytes to stimulation of lactate production by catechola...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Cytotoxicity control of silicon nanoparticles by biopolymer coating and ultrasound irradiation for cancer theranostic applications

Nanotechnology, 2017

Silicon nanoparticles (SiNPs) prepared by mechanical grinding of luminescent porous silicon were ... more Silicon nanoparticles (SiNPs) prepared by mechanical grinding of luminescent porous silicon were coated with a biopolymer (dextran) and investigated as a potential theranostic agent for bioimaging and sonodynamic therapy. Transmission electron microscopy, photoluminescence and Raman scattering measurements of dextran-coated SiNPs gave evidence of their enhanced stability in water. In vitro experiments confirmed the lower cytotoxicity of the dextran-coated NPs in comparison with uncoated ones, especially for high concentrations of about 2 mg ml-1. Efficient uptake of the NPs by cancer cells was found using bioimaging in the optical transmittance and photoluminescence modes. Treatment of the cells with uptaken SiNPs by therapeutic ultrasound for 5-20 min resulted in a strong decrease in the number of living cells, while the total number of cells remained nearly unchanged. The obtained data indicate a 'mild' effect of the combined action of ultrasonic irradiation and SiNPs on cancer cells. The observed results reveal new opportunities for controlling the photoluminescent and sonosensitizing properties of silicon-based NPs for applications in the diagnostics and mild therapy of cancer.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Markers of vulnerable plaques in non-human primates under atherogenic diet

Atherosclerosis, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Nonlinear Optical Properties of Silicon Carbide (SiC) Nanoparticles by Carbothermal Reduction

Colloidal Nanoparticles for Biomedical Applications XI, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Milk Polar Lipids Affect In Vitro Digestive Lipolysis and Postprandial Lipid Metabolism in Mice

Journal of Nutrition, 2015

Bookmarks Related papers MentionsView impact

Research paper thumbnail of P174 Impact de différents lipides polaires sur l’absorption et le métabolisme des lipides: études in vitro sur cellules Caco-2 et in vivo chez la souris

Diabetes & Metabolism, 2015

Introduction Les maladies metaboliques d'origine nutritionnelle sont caracterisees par un met... more Introduction Les maladies metaboliques d'origine nutritionnelle sont caracterisees par un metabolisme des lipides perturbe incluant une hyperlipemie postprandiale. Dans ce contexte, un interet se developpe autour des effets des lipides polaires (LP), agents de texture largement utilises dans l'industrie alimentaire. Nous etudions donc l'impact de LP de differentes sources alimentaires (vegetal vs animal) sur la lipemie postprandiale. Materiels et methodes Des souris ont ete gavees avec 2 types d'emulsions, dont les gouttelettes de matiere grasse etaient recouvertes de LP laitiers ou de LP de soja. Le plasma et l'intestin grele ont ete collectes au cours de la digestion. Des cellules intestinales Caco-2/TC7 ont ete incubees 24 heures avec des micelles lipidiques contenant differents L P, phosphatidylcholine ou sphingomyeline (specifique des LP laitiers) pour analyse des chylomicrons secretes. Resultats Une heure apres gavage, les LP Laitiers induisent des concentrations plasmatiques de triglycerides et d'acides gras libres plus elevees que les LP de soja. L'effet inverse est observe apres 4 heures. Ces lipemies differentes sont associees a une moindre expression genique de proteines impliquees dans la secretion des chylomicrons, dans le duodenum du groupe LP laitiers a 4 heures. Ceci suggere que l'absorption et la metabolisation des lipides dependent du type de LP utilise, notamment via une modulation des genes dans l'enterocyte. In vitro , la presence de sphin-gomyeline dans les micelles induit une secretion plus importante de triglycerides sous la forme de plus petits chylomicrons. Ainsi, les effets observes in vivo sont probablement dus a la teneur elevee des LP laitiers en sphingomyeline. Conclusion Ces resultats suggerent que la qualite des lipides polaires utilises pour stabiliser une emulsion influence le metabolisme postprandial des lipides. Ces nouvelles connaissances pourraient servir a la mise en place de formulations alimentaires optimisees. Declaration d’interet Les auteurs declarent ne pas avoir d'interet direct ou indirect (financier ou en nature) avec un organisme prive, industriel ou commercial en relation avec le sujet presente.

Bookmarks Related papers MentionsView impact