Leptin down-regulates peroxisome proliferator-activated receptor gamma (PPAR-gamma) mRNA levels in primary human monocyte-derived macrophages.

Increased leptin levels are associated with cardiovascular disease in obesity although the mechanism is unknown. Peroxisome proliferator-activated receptor gamma (PPARgamma) is a key regulator of macrophage lipid metabolism and its activation by thiazolidinediones protects against atherosclerosis. The aim of this study was to assess the effects of human recombinant leptin on PPARgamma mRNA levels in primary human macrophages and macrophage-derived foam cells.

Impaired expression of NADH dehydrogenase subunit 1 and PPARgamma coactivator-1 in skeletal muscle of ZDF rats: restoration by troglitazone.

Type 2 diabetes has been related to a decrease of mitochondrial DNA (mtDNA) content. In this study, we show increased expression of the peroxisome proliferator-activated receptor-alpha (PPARalpha) and its target genes involved in fatty acid metabolism in skeletal muscle of Zucker Diabetic Fatty (ZDF) (fa/fa) rats. In contrast, the mRNA levels of genes involved in glucose transport and utilization (GLUT4 and phosphofructokinase) were decreased, whereas the expression of pyruvate dehydrogenase kinase 4 (PDK-4), which suppresses glucose oxidation, was increased.

Down-regulation of acyl-CoA oxidase gene expression in heart of troglitazone-treated mice through a mechanism involving chicken ovalbumin upstream promoter transcription factor II.

Cardiac expression of genes involved in fatty acid metabolism may suffer alterations depending on the substrate availability. We studied how troglitazone, an antidiabetic drug that selectively activates peroxisome proliferator-activated receptor gamma (PPARgamma), affected the expression of several of these genes. A single-day troglitazone administration (100 mg/kg/day) did not significantly alter plasma free fatty acids or triglyceride levels.

Differential effects of peroxisome proliferator-activated receptor activators on the mRNA levels of genes involved in lipid metabolism in primary human monocyte-derived macrophages.

Peroxisome proliferator-activated receptors (PPARs) are key regulators of macrophage lipid metabolism. We compared the effects of three PPAR activators (bezafibrate, fenofibrate, and troglitazone) on the mRNA levels of genes involved in lipid metabolism in primary human macrophages and macrophage-derived foam cells. Treatment of human macrophages for 24 hours with 100 micro mol/L bezafibrate, a nonselective drug that activates the 3 PPAR subtypes (PPARalpha, PPARbeta/delta, and PPARgamma), caused an 87% (P <.

Reductions in plasma cholesterol levels after fenofibrate treatment are negatively correlated with resistin expression in human adipose tissue.

The adipocyte-derived cytokine, resistin, has been proposed as the link between obesity and type 2 diabetes mellitus in murine models. In humans, resistin is identical to FIZZ3 (found in inflammatory zone 3), which belongs to a family of proteins that appears to be involved in inflammatory processes. To study the mechanisms by which fibrates improve glucose homeostasis, we determined resistin mRNA levels by using relative quantitative reverse-transcriptase-polymerase chain reaction (RT-PCR) in omental white adipose tissue samples obtained from patients treated with placebo or fenofibrate (200 mg/d) for 8 weeks before elective cholecystectomy.

Down-regulation of acyl-CoA oxidase gene expression and increased NF-kappaB activity in etomoxir-induced cardiac hypertrophy.

Activation of nuclear factor-kappaB (NF-kappaB) is required for hypertrophic growth of cardiomyocytes. Etomoxir is an irreversible inhibitor of carnitine palmitoyltransferase I (CPT-I) that activates peroxisome proliferator-activated receptor alpha (PPARalpha) and induces cardiac hypertrophy through an unknown mechanism. We studied the mRNA expression of genes involved in fatty acid oxidation in the heart of mice treated for 1 or 10 days with etomoxir (100 mg/kg/day).

Fibrate treatment does not modify the expression of acyl coenzyme A oxidase in human liver.

Background And Objectives: Fibrates induce hepatic peroxisome proliferation and carcinogenesis in rodents by activating peroxisome proliferator-activated receptor alpha (PPAR(alpha)). There is no conclusive evidence that humans are unresponsive to peroxisome proliferation, and concern exists about the long-term safety of fibrate treatment.

Methods: In a university hospital setting, 48 patients with uncomplicated gallstones and a serum level of low-density lipoprotein cholesterol greater than 130 mg/dL were randomly assigned to open-label treatment with bezafibrate (400 mg/d), fenofibrate (200 mg/d), gemfibrozil (900 mg/d), or placebo for 8 weeks before elective cholecystectomy.

Increased beta -oxidation but no insulin resistance or glucose intolerance in mice lacking adiponectin.

Previous reports showed that recombinant fragments of adiponectin (adipo) displayed pharmacological effects when injected into rodents, but the relevance of these observations to the physiological function of adipo is unclear. We generated Adipo(-/-) mice by gene targeting. Adipo(-/-) mice are fertile with normal body and fat pad weights.

Increased reactive oxygen species production down-regulates peroxisome proliferator-activated alpha pathway in C2C12 skeletal muscle cells.

Generation of reactive oxygen species may contribute to the pathogenesis of diseases involving intracellular lipid accumulation. To explore the mechanisms leading to these pathologies we tested the effects of etomoxir, an inhibitor of carnitine palmitoyltransferase I which contains a fatty acid-derived structure, in C2C12 skeletal muscle cells. Etomoxir treatment for 24 h resulted in a down-regulation of peroxisome proliferator-activated receptor alpha (PPARalpha) mRNA expression, achieving an 87% reduction at 80 microm etomoxir.