RESUMEN

BACKGROUND: Cytochrome oxidase IV complex regulates energy production in mitochondria. Therefore, we determined the relation of COX genes with atherosclerosis in mice and pigs. METHODS AND RESULTS: First, we compared atherosclerosis in the aortic arch of age-matched (24 weeks) C57BL/6J control (n = 10), LDL-receptor deficient (n = 8), leptin-deficient ob/ob (n = 10), and double knock-out (lacking LDL-receptor and leptin) mice (n = 12). Low aortic mitochondria-encoded cytochrome oxidase 1 in obese diabetic double knock-out mice was associated with a larger plaque area and higher propensity of M1 macrophages and oxidized LDL. Caloric restriction increased mitochondria-encoded cytochrome oxidase 1 and reduced plaque area and oxidized LDL. This was associated with a reduction of titer of anti-oxidized LDL antibodies, a proxy of systemic oxidative stress. Low of mitochondria-encoded cytochrome oxidase 1 was related to low expression of peroxisome proliferative activated receptors α, δ, and γ and of peroxisome proliferative activated receptor, gamma, co-activator 1 alpha reflecting mitochondrial dysfunction. Caloric restriction increased them. To investigate if there was a diabetic/obesity requirement for mitochondria-encoded cytochrome oxidase 1 to be down-regulated, we then studied atherosclerosis in LAD of hypercholesterolemic pigs (n = 37). Pigs at the end of the study were divided in three groups based on increasing LAD plaque complexity according to Stary (Stary I: n = 12; Stary II: n = 13; Stary III: n = 12). Low mitochondria-encoded cytochrome oxidase 1 in isolated plaque macrophages was associated with more complex coronary plaques and oxidized LDL. Nucleus-encoded cytochrome oxidase 4I1 and cytochrome oxidase 10 did not correlate with plaque complexity and oxidative stress. In mice and pigs, MT-COI was inversely related to insulin resistance. CONCLUSIONS: Low MT-COI is related to mitochondrial dysfunction, oxidative stress and atherosclerosis and plaque complexity.

Asunto(s)

Aterosclerosis/etiología , Deficiencia de Citocromo-c Oxidasa/complicaciones , Deficiencia de Citocromo-c Oxidasa/fisiopatología , Complejo IV de Transporte de Electrones/fisiología , Mitocondrias/metabolismo , Porcinos Enanos/metabolismo , Animales , Aorta Torácica/metabolismo , Aorta Torácica/patología , Aterosclerosis/enzimología , Aterosclerosis/genética , Restricción Calórica , Vasos Coronarios/metabolismo , Vasos Coronarios/patología , Deficiencia de Citocromo-c Oxidasa/patología , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Complejo IV de Transporte de Electrones/genética , Metabolismo Energético , Hipercolesterolemia/enzimología , Hipercolesterolemia/patología , Resistencia a la Insulina , Leptina/deficiencia , Leptina/genética , Lipoproteínas LDL/metabolismo , Macrófagos/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Obesos , Coactivadores de Receptor Nuclear/biosíntesis , Coactivadores de Receptor Nuclear/genética , Estrés Oxidativo , Receptores Activados del Proliferador del Peroxisoma/biosíntesis , Receptores Activados del Proliferador del Peroxisoma/genética , Placa Aterosclerótica/patología , Receptores de LDL/deficiencia , Receptores de LDL/genética , Receptores de Leptina/deficiencia , Receptores de Leptina/genética , Porcinos

RESUMEN

There is a close interaction between Type 2 Diabetes, obesity and liver disease. We have studied the effects of the two most abundant Stevia-derived steviol glycosides, stevioside and rebaudioside A, and their aglycol derivative steviol on liver steatosis and the hepatic effects of lipotoxicity using a mouse model of obesity and insulin resistance. We treated ob/ob and LDLR-double deficient mice with stevioside (10 mg⋅kg(-1)⋅day-1 p.o., n = 8), rebaudioside A (12 mg⋅kg(-1)⋅day-1 p.o., n = 8), or steviol (5 mg⋅kg(-1)⋅day(-1) p.o., n = 8). We determined their effects on liver steatosis and on the metabolic effects of lipotoxicity by histological analysis, and by combined gene-expression and metabolomic analyses. All compounds attenuated hepatic steatosis. This could be explained by improved glucose metabolism, fat catabolism, bile acid metabolism, and lipid storage and transport. We identified PPARs as important regulators and observed differences in effects on insulin resistance, inflammation and oxidative stress between Stevia-derived compounds. We conclude that Stevia-derived compounds reduce hepatic steatosis to a similar extent, despite differences in effects on glucose and lipid metabolism, and inflammation and oxidative stress. Thus our data show that liver toxicity can be reduced through several pathophysiological changes. Further identification of active metabolites and underlying mechanisms are warranted.

Asunto(s)

Hígado Graso/tratamiento farmacológico , Hígado/efectos de los fármacos , Preparaciones de Plantas/farmacología , Stevia/química , Transcriptoma , Aminoácidos/metabolismo , Animales , Ácidos y Sales Biliares/metabolismo , Modelos Animales de Enfermedad , Diterpenos de Tipo Kaurano/farmacología , Glucosa/metabolismo , Glucósidos/farmacología , Glutatión/metabolismo , Resistencia a la Insulina , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/metabolismo , Masculino , Metabolómica , Ratones , Ratones Obesos , Obesidad/tratamiento farmacológico , Estrés Oxidativo/efectos de los fármacos , Receptores Activados del Proliferador del Peroxisoma/metabolismo

RESUMEN

Peroxisome proliferator-activated receptors (PPAR) play an important role in the regulation of lipid and glucose metabolism, inflammatory, and vascular responses. We show the effect of treatment with two PPAR agonists, fenofibrate (FF) and rosiglitazone (RSG), on ob/ob and LDLR-double deficient mice, by combined gene-expression and metabolomic analyses. Male mice were daily treated for 12 weeks with RSG (10 mg·kg(1-)·day(-1) per os (p.o.), n = 8) and FF (50 mg·kg(1-)·day(-1) p.o., n = 8). Twelve untreated ob/ob and LDLR-double deficient mice were used as controls. To integrate the transcriptomic and metabolomic results, we designed a hierarchical algorithm, based on the average linkage method in clustering. Data were also interpreted with the Ingenuity Pathway Analysis program. FF and RSG treatments significantly increased the hepatic triglyceride content in the liver when compared with the control group, and the treatments induced an increase in the number and size of hepatic lipid droplets. Both drugs simultaneously activate pro-steatotic and antisteatotic metabolic pathways with a well-ordered result of aggravation of the hepatic lipid accumulation. The present study is a cautionary note not only to researchers on the basic mechanism of the action of PPAR activators but also to the use of these compounds in clinical practice.

Asunto(s)

Hígado Graso/metabolismo , Fenofibrato/efectos adversos , Hiperlipidemias/metabolismo , Hipoglucemiantes/efectos adversos , Hipolipemiantes/efectos adversos , Obesidad/metabolismo , Tiazolidinedionas/efectos adversos , Animales , Modelos Animales de Enfermedad , Hígado Graso/inducido químicamente , Hígado Graso/tratamiento farmacológico , Hígado Graso/patología , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Hiperlipidemias/tratamiento farmacológico , Hiperlipidemias/patología , Hígado/química , Hígado/metabolismo , Hígado/patología , Masculino , Metaboloma , Ratones , Ratones Transgénicos , Obesidad/tratamiento farmacológico , Obesidad/patología , Receptores Activados del Proliferador del Peroxisoma/agonistas , Receptores Activados del Proliferador del Peroxisoma/genética , Receptores Activados del Proliferador del Peroxisoma/metabolismo , Mapeo de Interacción de Proteínas , Rosiglitazona , Transducción de Señal , Transcriptoma

RESUMEN

Synthetic peroxisome proliferator-activated receptor (PPAR) agonists are used to treat dyslipidemia and insulin resistance. In this study, we examined molecular mechanisms that explain differential effects of a PPARα agonist (fenofibrate) and a PPARγ agonist (rosiglitazone) on macrophages during obesity-induced atherogenesis. Twelve-week-old mice with combined leptin and LDL-receptor deficiency (DKO) were treated with fenofibrate, rosiglitazone or placebo for 12 weeks. Only rosiglitazone improved adipocyte function, restored insulin sensitivity, and inhibited atherosclerosis by decreasing lipid-loaded macrophages. In addition, it increased interleukin-1 receptor-associated kinase-3 (Irak3) and decreased monocyte chemoattractant protein-1 (Mcp1) expressions, indicative of a switch from M1 to M2 macrophages. The differences between fenofibrate and rosiglitazone were independent of Pparγ expression. In bone marrow-derived macrophages (BMDM), we identified the rosiglitazone-associated increase in adiponectin as cause of the increase in Irak3. Interestingly, the deletion of Irak3 in BMDM (IRAK3(-/-) BMDM) resulted in activation of the canonical NFκB signaling pathway and increased Mcp1 protein secretion. Rosiglitazone could not decrease the elevated Mcp1 secretion in IRAK3(-/-) BMDM directly and fenofibrate even increased the secretion, possibly due to increased mitochondrial reactive oxygen species production. Furthermore, aortic extracts of high-fat insulin-resistant LDL-receptor deficient mice, with lower adiponectin and Irak3 and higher Mcp1, showed accelerated atherosclerosis. In aggregate, our results emphasize an interaction between PPAR agonist-mediated increase in adiponectin and macrophage-associated Irak3 in the protection against atherosclerosis by PPAR agonists.

Asunto(s)

Adiponectina/metabolismo , Quimiocina CCL2/metabolismo , Resistencia a la Insulina , Quinasas Asociadas a Receptores de Interleucina-1/metabolismo , Obesidad/metabolismo , Receptores Activados del Proliferador del Peroxisoma/agonistas , Placa Aterosclerótica/metabolismo , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Adipocitos/patología , Adiponectina/sangre , Animales , Dieta Alta en Grasa , Fenofibrato/farmacología , Fenofibrato/uso terapéutico , Inflamación/sangre , Inflamación/tratamiento farmacológico , Inflamación/patología , Insulina/farmacología , Leptina/sangre , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Obesidad/sangre , Obesidad/tratamiento farmacológico , Obesidad/fisiopatología , PPAR alfa/agonistas , PPAR alfa/metabolismo , PPAR gamma/agonistas , PPAR gamma/metabolismo , Receptores Activados del Proliferador del Peroxisoma/metabolismo , Placa Aterosclerótica/tratamiento farmacológico , Placa Aterosclerótica/patología , Rosiglitazona , Tiazolidinedionas/farmacología , Tiazolidinedionas/uso terapéutico

RESUMEN

CD36 is recognized as a lipid and fatty acid receptor and plays an important role in the metabolic syndrome and associated cardiac events. The pleiotropic activity and the multiple molecular associations of this scavenger receptor with membrane associated molecules in different cells and tissues have however questioned its potential as a therapeutic target. The present study shows that it is possible to identify low molecular weight chemicals that can block the CD36 binding and uptake functions. These inhibitors were able to reduce arterial lipid deposition, fatty acid intestinal transit, plasma concentration of triglycerides and glucose, to improve insulin sensitivity, glucose tolerance and to reduce the plasma concentration of HbAc1 in different and independent rodent models. Correlation between the anti-CD36 activity of these inhibitors and the known pathophysiological activity of this scavenger receptor in the development of atherosclerosis and diabetes were observed at pharmacological doses. Thus, CD36 might represent an attractive therapeutic target.

Asunto(s)

Aterosclerosis/prevención & control , Antígenos CD36/metabolismo , Complicaciones de la Diabetes/prevención & control , Dislipidemias/prevención & control , Hipertrigliceridemia/metabolismo , Tiofenos/farmacología , Animales , Aterosclerosis/etiología , Bencimidazoles , Antígenos CD36/genética , Línea Celular , Modelos Animales de Enfermedad , Dislipidemias/etiología , Humanos , Hipertrigliceridemia/tratamiento farmacológico , Resistencia a la Insulina , Masculino , Ratones , Periodo Posprandial , Ratas , Ratas Wistar , Tiofenos/administración & dosificación

RESUMEN

BACKGROUND: Visceral obesity is associated with the rising incidence of type 2 diabetes and metabolic syndrome. Low-grade chronic inflammation and oxidative stress synergize in obesity and obesity-induced disorders. OBJECTIVE: We searched a cluster of molecules that support interactions between these stress conditions in monocytes. METHODS: RNA expressions in blood monocytes of two independent cohorts comprising 21 and 102 obese persons and 46 age-matched controls were determined by microarray and independently validated by quantitative RT-PCR analysis. The effect of three-month weight loss after bariatric surgery was determined. The effect of RNA silencing on inflammation and oxidative stress was studied in human monocytic THP-1 cells. RESULTS: Interleukin-1 receptor-associated kinase-3 (IRAK3), key inhibitor of IRAK/NFκB-mediated chronic inflammation, is downregulated in monocytes of obese persons. Low IRAK3 was associated with high superoxide dismutase-2 (SOD2), a marker of mitochondrial oxidative stress. A comparable expression profile was also detected in visceral adipose tissue of the same obese subjects. Low IRAK3 and high SOD2 was associated with a high prevalence of metabolic syndrome (odds ratio: 9.3; sensitivity: 91%; specificity: 77%). By comparison, the odds ratio of high-sensitivity C-reactive protein, a widely used marker of systemic inflammation, was 4.3 (sensitivity: 69%; specificity: 66%). Weight loss was associated with an increase in IRAK3 and a decrease in SOD2, in association with a lowering of systemic inflammation and a decreasing number of metabolic syndrome components. We identified the increase in reactive oxygen species in combination with obesity-associated low adiponectin and high glucose and interleukin-6 as cause of the decrease in IRAK3 in THP-1 cells in vitro. CONCLUSION: IRAK3 is a key inhibitor of inflammation in association with obesity and metabolic syndrome. Our data warrant further evaluation of IRAK3 as a diagnostic and prognostic marker, and as a target for intervention.

Asunto(s)

Inflamación/genética , Quinasas Asociadas a Receptores de Interleucina-1/genética , Síndrome Metabólico/genética , Obesidad/genética , Adipocitos/metabolismo , Adipogénesis/genética , Adulto , Línea Celular , Células Cultivadas , Estudios de Cohortes , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Femenino , Perfilación de la Expresión Génica , Humanos , Inflamación/metabolismo , Quinasas Asociadas a Receptores de Interleucina-1/sangre , Quinasas Asociadas a Receptores de Interleucina-1/metabolismo , Grasa Intraabdominal/metabolismo , Masculino , Síndrome Metabólico/complicaciones , Síndrome Metabólico/metabolismo , Persona de Mediana Edad , Monocitos/metabolismo , Obesidad/complicaciones , Obesidad/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/genética , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo

RESUMEN

OBJECTIVE: To study the association of PAF-acetyl hydrolase (PAFAH) activity with inflammation, oxidative stress, and atherosclerosis in hypercholesterolemic swine. METHODS AND RESULTS: Cholesterol-rich diet feeding of miniature pigs was associated with an increase in PAFAH activity and an increase of the PAFAH to PON1 ratio. PLA2G7 RNA (coding for PAFAH) expression was increased in blood monocytes and plaque macrophages. Increased PAFAH activity was associated with higher plasma lysophosphatidylcholine and correlated with oxidized LDL. In THP1 monocytes and macrophages and in human blood-derived macrophages, oxidized LDL induced PLA2G7 RNA expression. Atherogenic diet feeding induced the accumulation of macrophages and oxidized LDL in the arterial wall leading to atherosclerosis. PAFAH activity correlated positively with plaque size and TNFalpha expression in plaque macrophages. CONCLUSIONS: We demonstrated that an increase in PAFAH activity was associated with increased levels of lysophosphatidylcholine, oxidized LDL, and inflammation, resulting in accelerated atherosclerosis in hypercholesterolemic minipigs. The significant correlation between PLA2G7 RNA expression in plaque macrophages and plasma PAFAH activity suggests that the latter is a consequence, rather than a cause of macrophage accumulation. Our cell experiments suggest that oxidized LDL can induce PAFAH, resulting in accumulation of lysophosphatidylcholine that increases the inflammatory action of oxidized LDL.

Asunto(s)

1-Alquil-2-acetilglicerofosfocolina Esterasa/metabolismo , Aterosclerosis/etiología , Aterosclerosis/metabolismo , Hipercolesterolemia/complicaciones , Hipercolesterolemia/metabolismo , Inflamación/etiología , Inflamación/metabolismo , Metabolismo de los Lípidos , 1-Alquil-2-acetilglicerofosfocolina Esterasa/genética , Secuencia de Aminoácidos , Animales , Arildialquilfosfatasa/metabolismo , Aterosclerosis/genética , Aterosclerosis/patología , Vasos Coronarios/patología , Dieta Aterogénica , Expresión Génica , Humanos , Hipercolesterolemia/genética , Inflamación/genética , Macrófagos/metabolismo , Macrófagos/patología , Datos de Secuencia Molecular , Oxidación-Reducción , Estrés Oxidativo , ARN/genética , ARN/metabolismo , Porcinos , Porcinos Enanos