Overexpression of leptin mRNA in mesenteric adipose tissue in inflammatory bowel diseases.

Background: Leptin, a protein with a cytokine-like structure, is produced predominantly by adipocytes. It appears to play a key role in immune responses by increasing the secretion of Th1 and pro-inflammatory cytokines. As fat-wrapping is a characteristic feature of Crohn's disease (CD), and as increased leptin levels have been reported in animal models of intestinal inflammation, this study investigated whether mesenteric adipose tissue could be a source of leptin in human inflammatory bowel disease (IBD).

[Obesity and inflammation: the adipocytokines].

It is now well documented that obesity is associated with a chronic, low grade, inflammatory state. The serum concentrations of a number of inflammatory markers, such as CRP, fibrinogene or serum amyloids are increased in obese subjects. More importantly, the levels of several pro-inflammatory cytokines, including TNFalpha, IL-6 and leptin are significantly higher in the plasma of obese patients.

Transcriptomic classification of antitumor agents: application to the analysis of the antitumoral effect of SR31747A.

SR31747A is a sigma ligand that exhibits a potent antitumoral activity on various human tumor cell lines both in vitro and in vivo. To understand its mode of action, we used DNA microarray technology combined with a new bioinformatic approach to identify genes that are modulated by SR31747A in different human breast or prostate cancer cell lines. The SR31747A transcriptional signature was also compared with that of seven different representative anticancer drugs commonly used in the clinic.

Decreased muscle acetyl-coenzyme A carboxylase 2 mRNA and insulin resistance in formerly obese subjects.

Objective: A relationship between free fatty acids, intramuscular triglycerides (TG(M)s), and insulin resistance is widely accepted. The intracellular level of malonyl-coenzyme A (CoA) was suggested to be the possible link. Acetyl-CoA carboxylase (ACC) is a key enzyme in fatty acid metabolism, catalyzing the synthesis of malonyl-CoA, a fatty acid acyl-chain elongation unit, from acetyl-CoA.

Modified quantitative insulin sensitivity check index is better correlated to hyperinsulinemic glucose clamp than other fasting-based index of insulin sensitivity in different insulin-resistant states.

Fasting-based index estimates of insulin sensitivity were compared with euglycemic hyperinsulinemic clamp (IS clamp) measurements in 148 subjects: normal controls (n = 46), and obese (n = 12), polycystic ovary syndrome (n = 16), first-degree relatives of type 2 diabetic (n = 17), impaired glucose tolerance (n = 28), and type 2 diabetic (n = 29) patients. The fasting-based indexes tested included log homeostasis model assessment (HOMA), the quantitative insulin sensitivity check index (QUICKI), the revised QUICKI, and a new revised QUICKI using fasting plasma glycerol. In the population studied, at 40 mU/m(2).

Effect of carbohydrate overfeeding on whole body and adipose tissue metabolism in humans.

Objective: To evaluate the effect of a 4-day carbohydrate overfeeding on whole body net de novo lipogenesis and on markers of de novo lipogenesis in subcutaneous adipose tissue of healthy lean humans.

Research Methods And Procedures: Nine healthy lean volunteers (five men and four women) were studied after 4 days of either isocaloric feeding or carbohydrate overfeeding. On each occasion, they underwent a metabolic study during which their energy expenditure and net substrate oxidation rates (indirect calorimetry), and the fractional activity of the pentose-phosphate pathway in subcutaneous adipose tissue (subcutaneous microdialysis with 1,6(13)C2,6,6(2)H2 glucose) were assessed before and after administration of glucose.

Intramyocitic lipid accumulation and SREBP-1c expression are related to insulin resistance and cardiovascular risk in morbid obesity.

The aim of this study was to investigate the sterol regulatory element-binding protein 1c (SREBP1c) mRNA muscle expression in morbid obese subjects before and after massive lipid malabsorption due to bariatric surgery (bilio-pancreatic diversion, BPD). We studied 11 obese subjects (BMI 49+/-2 kg/m2) before and 24 months after BPD. Skeletal muscle SREBP1c mRNA expression was determined using RT-competitive PCR.

Identification and pharmacological characterization of SRBP-2: a novel SR31747A-binding protein.

SR31747A is a sigma ligand with potent antiproliferative activity against tumor cells and for which three binding proteins have been identified to date: (a) SRBP-1 (also called sigma 1); (b) HIS; and (c) sigma 2. In this study, we characterized an additional SR31747A binding site, i.e.

Glucose-to-insulin ratio rather than sex hormone-binding globulin and adiponectin levels is the best predictor of insulin resistance in nonobese women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS), the main androgen disorder in women, has been suggested to be associated with a high risk of developing cardiovascular disease and type 2 diabetes. In many PCOS patients, overweight or central obesity is generally associated with increases in fasting insulin levels, insulin resistance, and glucose intolerance, and has been identified as a target for new therapeutic strategy, including early change in lifestyle. Early biochemical marker(s) for identifying at-risk patients will be useful for prevention studies.

What kind of simple fasting index should be used to estimate insulin sensitivity in humans?

The hyperinsulinemic euglycemic glucose clamp method is the gold standard for measuring insulin resistance. However it is complex, and simple indexes have been developed. Some of them are based on formulae that calculate the product or the addition of fasting plasma insulin and glucose values whereas others are based on their ratios.

Expression of adipogenic transcription factors, peroxisome proliferator-activated receptor gamma co-activator 1, IL-6 and CD45 in subcutaneous adipose tissue in lipodystrophy associated with highly active antiretroviral therapy.

Objective: To determine the expressions of multiple genes in the subcutaneous adipose tissue of HIV-positive, highly active antiretroviral therapy (HAART)-treated patients with and without lipodystrophy.

Design And Methods: Real-time polymerase chain reaction was used to measure gene expressions in this cross-sectional study.

Results: The messenger RNA concentrations of adipose transcription factors (peroxisome proliferator-activated receptor (PPAR) gamma and delta and sterol regulatory element binding protein 1c) were all significantly lower in the lipodystrophic than the non-lipodystrophic group.

Lifestyle changes and lipid metabolism gene expression and protein content in skeletal muscle of subjects with impaired glucose tolerance.

Aims/hypothesis: Skeletal muscle of pre-diabetic patients is characterised by a diminished capacity to handle fatty acids. A diminished content of several enzymes involved in fatty-acid transport and oxidation have been suggested to underlie these defects. The aim of this study was to investigate whether the combination of dietary advice, increased physical activity and weight loss improves lipid metabolic gene and protein expression in skeletal muscle of subjects with impaired glucose tolerance.

Effect of beta1- and beta2-adrenergic stimulation on energy expenditure, substrate oxidation, and UCP3 expression in humans.

In humans, beta-adrenergic stimulation increases energy and fat metabolism. In the case of beta1-adrenergic stimulation, it is fueled by an increased lipolysis. We examined the effect of beta2-adrenergic stimulation, with and without a blocker of lipolysis, on thermogenesis and substrate oxidation.

Reduced activation of phosphatidylinositol-3 kinase and increased serine 636 phosphorylation of insulin receptor substrate-1 in primary culture of skeletal muscle cells from patients with type 2 diabetes.

To understand better the defects in the proximal steps of insulin signaling during type 2 diabetes, we used differentiated human skeletal muscle cells in primary culture. When compared with cells from control subjects, myotubes established from patients with type 2 diabetes presented the same defects as those previously evidenced in vivo in muscle biopsies, including defective stimulation of phosphatidylinositol (PI) 3-kinase activity, decreased association of PI 3-kinase with insulin receptor substrate (IRS)-1 and reduced IRS-1 tyrosine phosphorylation during insulin stimulation. In contrast to IRS-1, the signaling through IRS-2 was not altered.

Decreased uncoupling protein expression and intramyocytic triglyceride depletion in formerly obese subjects.

Objective: To examine the muscular uncoupling protein expression 2 (UCP2) and UCP3 gene expression in morbid obese subjects before and after bariatric surgery [bilio-pancreatic diversion (BPD)].

Research Methods And Procedures: Eleven obese subjects (BMI = 49 +/- 2 kg/m(2)) were studied before BPD and 24 months after BPD. Skeletal muscle UCP2 and UCP3 mRNA was measured using reverse transcriptase-competitive polymerase chain reaction and UCP3 protein by Western blotting.

Effect of the Pro12Ala polymorphism in the peroxisome proliferator-activated receptor (PPAR) gamma2 gene on the expression of PPARgamma target genes in adipose tissue of massively obese subjects.

The aim was to study the effect of the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor (PPAR) gamma2 gene on the expression of PPARgamma target genes in adipose tissue. Adipose tissue samples were collected from 30 massively obese subjects (10 men and 20 women) from omental, sc abdominal, and femoral depots. The mRNA expression of PPARgamma1, PPARgamma2, lipoprotein lipase, p85alpha phosphatidylinositol 3-kinase, and uncoupling protein 2 were quantified by reverse transcription-competitive PCR.

Microarray profiling of human skeletal muscle reveals that insulin regulates approximately 800 genes during a hyperinsulinemic clamp.

Insulin action in target tissues involved precise regulation of gene expression. To define the set of insulin-regulated genes in human skeletal muscle, we analyzed the global changes in mRNA levels during a 3-h hyperinsulinemic euglycemic clamp in vastus lateralis muscle of six healthy subjects. Using 29,308 cDNA element microarrays, we found that the mRNA expression of 762 genes, including 353 expressed sequence tags, was significantly modified during insulin infusion.

Mitofusin-2 determines mitochondrial network architecture and mitochondrial metabolism. A novel regulatory mechanism altered in obesity.

In many cells and specially in muscle, mitochondria form elongated filaments or a branched reticulum. We show that Mfn2 (mitofusin 2), a mitochondrial membrane protein that participates in mitochondrial fusion in mammalian cells, is induced during myogenesis and contributes to the maintenance and operation of the mitochondrial network. Repression of Mfn2 caused morphological and functional fragmentation of the mitochondrial network into independent clusters.

Reduced PDK4 expression associates with increased insulin sensitivity in postobese patients.

Objective: The aim of this study was to verify whether changes in PDK4 mRNA expression in skeletal muscle in formerly obese subjects who underwent malabsorptive bariatric surgery [bilio-pancreatic diversion (BPD)] might be related to insulin sensitivity improvement, and if these possible modifications might correlate with a reduction of the intramyocytic lipid level.

Research Methods And Procedures: Six obese women (body mass index 46.6 +/- 8.

SR31747A is a sigma receptor ligand exhibiting antitumoural activity both in vitro and in vivo.

SR31747A is a recently described sigma receptor ligand that binds SR31747A-binding protein 1 (SR-BP) and emopamil-binding protein (EBP) (also called the sigma 1 receptor and the human sterol isomerase (HSI), respectively), and has immunoregulatory and antiproliferative activities. To further investigate its antitumour activity and focusing on cancers, which are sensitive to the molecule, we measured the proliferation of different human epithelial breast or prostate cancer cell lines following in vitro and in vivo SR31747A treatment. Firstly, in vitro, we found that nanomolar concentrations of SR31747A dramatically inhibited cell proliferation in both hormono-responsive and -unresponsive cancer cell lines.

Adipose tissue gene expression in patients with a loss of function mutation in the leptin receptor.

Background: In order to maintain body weight regulation, leptin directly or indirectly signals nutritional changes to key organs, but little is known about its target genes in human adipose tissue. Leptin receptor loss of function is a unique way to explore the role of leptin in the regulation of adipose tissue.

Objective: We studied the consequences of the absence of leptin signaling on adipocyte gene expression in two girls with a mutation in the leptin receptor.

Expression and regulation by insulin of low-density lipoprotein receptor-related protein mRNA in human skeletal muscle.

Evidence suggests that increased hydrolysis and/or uptake of triglyceride-rich lipoprotein particles in skeletal muscle can be involved in insulin resistance. We determined the steady state mRNA levels of the low-density lipoprotein-related receptor (LRP) and lipoprotein lipase (LPL) in skeletal muscle of eight healthy lean control subjects, eight type 2 diabetic patients and eight nondiabetic obese individuals. The regulation by insulin of LRP and LPL mRNA expression was also investigated in biopsies taken before and at the end of a 3 h euglycemic hyperinsulinemic clamp (insulinemia of about 1 nM).

Involvement of the peripheral benzodiazepine receptor in the development of rheumatoid arthritis in Mrl/lpr mice.

In this study, the effects of different peripheral benzodiazapine receptor ligands: PK 11195 [1-(2-chloro-phenyl)-N-methyl-N-(1-methylpropyl)-1-isoquinoline carboxamide], Ro5-4864 [7-chloro-5-(4-chlorophenyl)-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one] and the newly described SSR 180575 (7-chloro-N,N,5-trimethyl-4-oxo-3-phenyl-3,5-dihydro-4H-pyridozine[4,5-b] indole-1-acetamide) were analysed on the progression and severity of rheumatoid arthritis in vivo in the Mrl/lpr mice model, following chronic treatment (at 3 mg/kg, i.p. for 30 days).

The effect of a 3-month low-intensity endurance training program on fat oxidation and acetyl-CoA carboxylase-2 expression.

Endurance training has been shown to increase fat oxidation both at rest and during exercise. However, most exercise training studies have been performed at high exercise intensity in well-trained athletes, and not much is known about the effect of a low-intensity training program on fat oxidation capacity in lean sedentary humans. Here, we examine the effect of 3-month low-intensity training program on total and intramuscular triglyceride (IMTG)- and/or VLDL-derived fat oxidation capacity and skeletal muscle mRNA expression.