Expression of inflammation-related genes in gluteal and abdominal subcutaneous adipose tissue during weight-reducing dietary intervention in obese women.

Accumulation of adipose tissue in lower body lowers risk of cardiovascular and metabolic disorders. The molecular basis of this protective effect of gluteofemoral depot is not clear. The aim of this study was to compare the profile of expression of inflammation-related genes in subcutaneous gluteal (sGAT) and abdominal (sAAT) adipose tissue at baseline and in response to multiphase weight-reducing dietary intervention (DI). 14 premenopausal healthy obese women underwent a 6 months' DI consisting of 1 month very-low-calorie-diet (VLCD), subsequent 2 months' low-calorie-diet and 3 months' weight maintenance diet (WM). Paired samples of sGAT and sAAT were obtained before and at the end of VLCD and WM periods. mRNA expression of 17 genes (macrophage markers, cytokines) was measured using RT-qPCR on chip-platform. At baseline, there were no differences in gene expression of macrophage markers and cytokines between sGAT and sAAT. The dynamic changes induced by DI were similar in both depots for all genes except for three cytokines (IL6, IL10, CCL2) that differed in their response during weight maintenance phase. The results show that, in obese women, there are no major differences between sGAT and sAAT in expression of inflammation-related genes at baseline conditions and in response to the weight-reducing DI.

The impact of obesity on secretion of adiponectin multimeric isoforms differs in visceral and subcutaneous adipose tissue.

OBJECTIVE: Hypoadiponectinemia observed in obesity is associated with insulin resistance, diabetes and atherosclerosis. The aim of the present study was to investigate secretion of adiponectin and its multimeric isoforms by explants derived from subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in obese and non-obese subjects. DESIGN: Paired samples of SAT and VAT and blood samples were obtained from 23 subjects (10 non-obese and 13 obese) undergoing elective abdominal surgery. Total adiponectin quantities and adiponectin isoforms were measured in conditioned media of explants derived from SAT and VAT using enzyme-linked immunosorbent assay and non-denaturing western blot, respectively. RESULTS: Total adiponectin plasma levels were lower in obese than in non-obese subjects (P<0.05). Secretion of total adiponectin in adipose tissue (AT) explants was lower in obese than in non-obese subjects in SAT (P<0.05) but not in VAT. In both, SAT and VAT, the most abundant isoform released into conditioned media was the high-molecular weight (HMW) form. Its relative proportion in relation to total adiponectin was higher in conditioned media of explants from both fat depots when compared with plasma (P<0.001). The proportion of secreted HMW vs total adiponectin was higher in VAT than in SAT explants in the group of non-obese individuals (49.3±3.1% in VAT vs 40.6±2.8% in SAT; P<0.01), whereas no difference between the two depots was found in obese subjects (46.2±3.0 % in VAT vs 46.0±2.4 % in SAT). CONCLUSION: Obesity is associated with the decrease of total adiponectin secretion in SAT. The profile of adiponectin isoforms secreted by SAT and VAT explants differs from that in plasma. Secretion of total adiponectin and HMW isoform of adiponectin are different in obese and non-obese subjects in relation to AT depot.

Macrophage gene expression is related to obesity and the metabolic syndrome in human subcutaneous fat as well as in visceral fat.

AIMS/HYPOTHESIS: Our goal was to identify a set of human adipose tissue macrophage (ATM)-specific markers and investigate whether their gene expression in subcutaneous adipose tissue (SAT) as well as in visceral adipose tissue (VAT) is related to obesity and to the occurrence of the metabolic syndrome. METHODS: ATM-specific markers were identified by DNA microarray analysis of adipose tissue cell types isolated from SAT of lean and obese individuals. We then analysed gene expression of these markers by reverse transcription quantitative PCR in paired samples of SAT and VAT from 53 women stratified into four groups (lean, overweight, obese and obese with the metabolic syndrome). Anthropometric measurements, euglycaemic-hyperinsulinaemic clamp, blood analysis and computed tomography scans were performed. RESULTS: A panel of 24 genes was selected as ATM-specific markers based on overexpression in ATM compared with other adipose tissue cell types. In SAT and VAT, gene expression of ATM markers was lowest in lean and highest in the metabolic syndrome group. mRNA levels in the two fat depots were negatively correlated with glucose disposal rate and positively associated with indices of adiposity and the metabolic syndrome. CONCLUSIONS/INTERPRETATION: In humans, expression of ATM-specific genes increases with the degree of adiposity and correlates with markers of insulin resistance and the metabolic syndrome to a similar degree in SAT and in VAT.

Dietary intervention-induced weight loss decreases macrophage content in adipose tissue of obese women.

OBJECTIVE: Accumulation of adipose tissue macrophages (ATMs) is observed in obesity and may participate in the development of insulin resistance and obesity-related complications. The aim of our study was to investigate the effect of long-term dietary intervention on ATM content in human adipose tissue. DESIGN: We performed a multi-phase longitudinal study. SUBJECTS AND MEASUREMENTS: A total of 27 obese pre-menopausal women (age 39 ± 2 years, body mass index 33.7 ± 0.5 kg m(-2)) underwent a 6-month dietary intervention consisting of two periods: 4 weeks of very low-calorie diet (VLCD) followed by weight stabilization composed of 2 months of low-calorie diet and 3 to 4 months of weight maintenance diet. At baseline and at the end of each dietary period, samples of subcutaneous adipose tissue (SAT) were obtained by needle biopsy and blood samples were drawn. ATMs were determined by flow cytometry using combinations of cell surface markers. Selected cytokine and chemokine plasma levels were measured using enzyme-linked immunosorbent assay. In addition, in a subgroup of 16 subjects, gene expression profiling of macrophage markers in SAT was performed using real-time PCR. RESULTS: Dietary intervention led to a significant decrease in body weight, plasma insulin and C-reactive protein levels. After VLCD, ATM content defined by CD45+/14+/206+ did not change, whereas it decreased at the end of the intervention. This decrease was associated with a downregulation of macrophage marker mRNA levels (CD14, CD163, CD68 and LYVE-1 (lymphatic vessel endothelial hyaluronan receptor-1)) and plasma levels of monocyte-chemoattractant protein-1 (MCP-1) and CXCL5 (chemokine (C-X-C motif) ligand 5). During the whole dietary intervention, the proportion of two ATM subpopulations distinguished by the CD16 marker was not changed. CONCLUSION: A 6-month weight-reducing dietary intervention, but not VLCD, promotes a decrease in the number of the whole ATM population with no change in the relative distribution of ATM subsets.

Visfatin expression in subcutaneous adipose tissue of pre-menopausal women: relation to hormones and weight reduction.

BACKGROUND: A novel adipokine, visfatin, was found to be related to adiposity in humans and regulated by a number of hormonal signals. The aim of this study was to investigate the relationships of visfatin expression in adipose tissue with potential regulatory factors such as insulin, testosterone and tumor necrosis factor-alpha (TNF-alpha) and to elucidate the effect of a diet induced weight reduction on adipose tissue mRNA expression and plasma levels of visfatin. MATERIALS AND METHODS: Biopsies of subcutaneous abdominal adipose tissue (SCAAT) and plasma samples were obtained at the beginning of the study from 47 pre-menopausal women (age 38.7 +/- 1.7 years, body mass index (BMI) 27.9 +/- 1.4 kg m(-2)), consisting of 15 lean, 16 overweight and 16 obese subjects. The subgroup of 32 overweight/obese women (age 42.1 +/- 1.9 years, BMI 31.2 +/- 0.9 kg m(-2)) underwent a 12 week hypocaloric weight reducing diet and samples were obtained at the end of the diet. Biopsy samples were analysed for visfatin and TNF-alpha mRNA levels and plasma was analysed for relevant metabolites and hormones. RESULTS: In the group of 47 subjects visfatin mRNA expression in SCAAT was negatively correlated with plasma free testosterone (r = -0. 363, P < 0.05) and BMI (r = -0.558, P < 0.01) and positively associated with adipose tissue TNF-alpha mRNA expression (r = 0.688, P < 0.01). The diet resulted in the reduction of body weight and in the decrease of plasma insulin, free testosterone and TNF-alpha levels. In the group of overweight/obese subjects visfatin mRNA in SCAAT increased after the diet and the diet induced increase was positively correlated with the magnitude of body weight loss. CONCLUSION: Visfatin mRNA expression in SCAAT is associated with TNF-alpha expression, plasma free testosterone and BMI in pre-menopausal women. A weight reducing hypocaloric diet results in the increase of visfatin mRNA in SCAAT.

Total adiponectin and adiponectin multimeric complexes in relation to weight loss-induced improvements in insulin sensitivity in obese women: the NUGENOB study.

AIM: Adiponectin increases insulin sensitivity, protects arterial walls against atherosclerosis, and regulates glucose metabolism, and is decreased in obese, insulin resistant, and type 2 diabetic patients. Adiponectin circulates in plasma as high, medium, and low molecular weight forms (HMW, MMW, and LMW). The HMW form was suggested to be closely associated with insulin sensitivity. This study investigated whether diet-induced changes in insulin sensitivity were associated with changes in adiponectin multimeric complexes. SUBJECTS: Twenty obese women with highest and twenty obese women with lowest diet induced changes in insulin sensitivity (responders and non-responders respectively), matched for weight loss (body mass index (BMI)=34.5 (s.d. 2.9) resp. 36.5 kg/m(2) (s.d. 4.0) for responders and non-responders), were selected from 292 women who underwent a 10-week low-caloric diet (LCD; 600 kcal/d less than energy requirements). Plasma HMW, MMW, and LMW forms of adiponectin were quantified using Western blot method. RESULTS: LCD induced comparable weight reduction in responders and non-responders by 8.2 and 7.6 kg. Homeostasis model assessment insulin resistance index decreased by 48.1% in responders and remained unchanged in non-responders. Total plasma adiponectin and the quantity of HMW and MMW remained unchanged in both groups, while LMW increased by 16.3% in non-responders. No differences between both groups were observed at baseline and after the study. Total plasma adiponectin, MMW, and LMW were negatively associated with fasting insulin levels at baseline. CONCLUSION: No differences in total plasma adiponectin, HMW, MMW, and LMW forms were observed between responders and non-responders following 10-week LCD, suggesting that adiponectin is not a major determinant of weight loss-induced improvements in insulin sensitivity.

Retinol-binding protein 4 expression in visceral and subcutaneous fat in human obesity.

Retinol binding protein 4 (RBP4) is a novel adipokine which might be involved in the development of insulin resistance. The aim of the study was to investigate the expression of RBP4 mRNA in subcutaneous and visceral fat depots and the relationship between RBP4 plasma and mRNA levels relative to indices of adiposity and insulin resistance. In 59 Caucasian women (BMI 20 to 49 kg/m(2)) paired samples of subcutaneous and visceral fat were obtained for RBP4, leptin and GLUT 4 mRNA analysis using reverse transcription-quantitative PCR. Euglycemic hyperinsulinemic clamp and computed tomography scans were performed. RBP4 mRNA levels as well as GLUT 4 mRNA and leptin mRNA levels were lower (P<0.001, P<0.01 and P<0.001, respectively) in visceral compared to subcutaneous fat. No differences were found in RBP4 mRNA expression in the two fat depots or in RBP4 plasma levels between subgroups of non-obese subjects (n=26), obese subjects without metabolic syndrome (n=17) and with metabolic syndrome (n=16). No correlations between RBP4 mRNA or plasma levels relative to adiposity, glucose disposal rate and GLUT 4 mRNA expression in adipose tissue were found. There was a weak positive correlation between plasma RBP4 and plasma triglycerides (r = 0.30, p<0.05) and between plasma RBP4 and blood glucose (r = 0.26, p<0.05). Regardless of the state of adiposity or insulin resistance, RBP4 expression in humans was lower in visceral than in subcutaneous fat. We found no direct relationship between either RBP4 mRNA or its plasma levels and the adiposity or insulin resistance.

The atrial natriuretic peptide- and catecholamine-induced lipolysis and expression of related genes in adipose tissue in hypothyroid and hyperthyroid patients.

Thyroid dysfunction is associated with several abnormalities in intermediary metabolism, including impairment of lipolytic response to catecholamines in subcutaneous abdominal adipose tissue (SCAAT). Atrial natriuretic peptide (ANP) is a powerful lipolytic peptide; however, the role of ANP-mediated lipolysis in thyroid disease has not been elucidated. The aim of this study was to investigate the role of thyroid hormones in the regulation of ANP-induced lipolysis as well as in the gene expression of hormone-sensitive lipase, phosphodiesterase 3B (PDE3B), uncoupling protein-2 (UCP2), natriuretic peptide receptor type A, and beta(2)-adrenergic receptor in SCAAT of hyperthyroid and hypothyroid patients. Gene expression in SCAAT was studied in 13 hypothyroid and 11 hyperthyroid age-matched women before and 2-4 mo after the normalization of their thyroid status. A microdialysis study was performed on a subset of nine hyperthyroid and 10 hypothyroid subjects. ANP- and isoprenaline-induced lipolyses were higher in hyperthyroid subjects, with no differences between the groups following treatment. Hormone-sensitive lipase gene expression was higher in hyperthyroid compared with hypothyroid subjects before treatment, whereas no difference was observed following treatment. No differences in gene expression of other genes were observed between the two groups. Following treatment, the gene expression of UCP2 decreased in hyperthyroid, whereas the expression of PDE3B decreased in hypothyroid subjects. We conclude that thyroid hormones regulate ANP- and isoprenaline-mediated lipolysis in human SCAAT in vivo. Increased lipolytic subcutaneous adipose tissue response in hyperthyroid patients may involve postreceptor signaling mechanisms.