FTO mRNA Expression in Extremely Obese and Type 2 Diabetic Human Omental and Subcutaneous Adipose Tissues

Background

Fat mass and obesity-associated protein (FTO) gene expression is known to correlate with obesity. Our aim was to investigate the FTO gene expression in paired omental and subcutaneous human adipose tissues from morbid and obese patients. To understand the role of CD68-positive macrophages in adipose tissues, the correlation with adiposity parameters such as adipocyte diameter and adipocyte radius was also measured. Drug and adiposity correlations were also analyzed.

Methods

Paired omental and subcutaneous adipose tissue were excised during elective surgery from morbidly obese (n?=?9) and obese (n?=?5) patients. FTO expressions were determined by quantitative PCR. Tissue sections were analyzed for their CD68 protein expressions by immunuhistochemistry.

Results

Omental and subcutaneous adipose tissue FTO gene expression levels were not found to differ significantly among morbidly obese and obese study groups. Serum aspartate aminotransferase e and alanine transaminase levels were found to be in negative correlation with subcutaneous fat tissue FTO expression rate. Antidiabetic drug use was found to be in correlation with adiposity. Both subcutaneous and omental fat cell diameters were found to have correlation with antidiabetic drug use. Omental fat cell diameter was found to enlarge together with omental CD68 protein expression. Subcutaneous macrophage number decreased while omental fat cell radius increased. Omental macrophage number was found in correlation with subcutaneous macrophage number.

Conclusions

Antidiabetic therapy was found to increase adiposity in omental and subcutaneous fat. Further research is needed with larger samples to explore the exact role of FTO in obesity.     

Plasma visfatin concentrations and fat depot-specific mRNA expression in humans

Visceral and subcutaneous adipose tissue display important metabolic differences that underlie the association of visceral obesity with obesity-related cardiovascular and metabolic alterations. Recently, visfatin was identified as an adipokine, which is predominantly secreted from visceral adipose tissue both in humans and mice. In this study, we examined whether visfatin plasma concentrations (using enzyme immunosorbent assay) and mRNA expression (using RT-PCR) in visceral and subcutaneous fat correlates with anthropometric and metabolic parameters in 189 subjects with a wide range of obesity, body fat distribution, insulin sensitivity, and glucose tolerance. Visfatin plasma concentration correlates positively with the visceral visfatin mRNA expression (r(2) = 0.17, P < 0.0001), BMI (r(2) = 0.062, P = 0.004), percent body fat (r(2) = 0.048, P = 0.01), and negatively with subcutaneous visfatin mRNA expression (r(2) = 0.18, P < 0.0001). However, in a subgroup of 73 individuals, in which visceral fat mass was calculated from computed tomography scans, there was no correlation between plasma visfatin concentrations and visceral fat mass. We found no significant correlation between visfatin plasma concentrations and parameters of insulin sensitivity, including fasting insulin, fasting plasma glucose concentrations, and the glucose infusion rate during the steady state of an euglycemic-hyperinsulinemic clamp independent of percent body fat. Visfatin gene expression was not different between visceral and subcutaneous adipose tissue in the entire study group nor in selected subgroups. We found a significant correlation between visceral visfatin gene expression and BMI (r(2) = 0.06, P = 0.001) and percent body fat (measured using dual-energy X-ray absorptiometry) (r(2) = 0.044, P = 0.004), whereas no significant association between BMI or percent body fat and subcutaneous visfatin mRNA expression existed (both P >0.5). In conclusion, visfatin plasma concentrations and visceral visfatin mRNA expression correlated with measures of obesity but not with visceral fat mass or waist-to-hip ratio. In addition, we did not find differences in visfatin mRNA expression between visceral and subcutaneous adipose tissue in humans.     

Higher Content of <Emphasis Type="Italic">Trans</Emphasis> Fatty Acids in Abdominal Visceral Fat of Morbidly Obese Individuals undergoing Bariatric Surgery compared to Non-Obese Subjects

Background: The purpose of this study was to determine the total content of trans fatty acids (TFA) in subcutaneous, retroperitoneal and visceral fat of morbidly obese and non-obese patients submitted to bariatric surgery or plastic and abdominal surgery. Methods: The adipose tissues were obtained by surgery; lipids were extracted, saponified and esterified. TFA were measured by FTIR-ATR spectroscopy. Results: The TFA average in obese patients was 6.3% for retroperitoneal and 8.7% for visceral fat. For non-obese patients, the figures were 6.9% (subcutaneous) and 9.3% (visceral). There was no difference between the groups. However, the TFA depot in visceral fat was higher than other fatty tissues for morbidly obese (P<0.001) and non-obese (P<0.05) patients. Conclusions: Our values for TFA content in all adipose tissues analyzed are higher than reported in other countries (3-6%). We showed more TFA in visceral adipose tissue than in other abdominal fat (subcutaneous and retroperitoneal) stores. The visceral adipose tissue level is worrisome because the higher rate of lipolysis in this tissue appears to be an important indicator of metabolic alterations and the levels of TFA found in adipose tissue presumably reflect the higher dietary intake of TFA by Brazilians.     

Relationship among Adiponectin, Adiponectin Gene Expression and Fatty Acids Composition in Morbidly Obese Patients

Background he aim of this study was to examine the relationship between adiponectin plasma circulating levels and its gene expression in two abdominal fat depots (subcutaneous and visceral) with the fatty acid composition of plasma and adipose tissue in morbidly obese subjects. Methods 20 patients (10 women and 10 men) were selected. All were morbidly obese (BMI ≥40 kg/m²) and admitted for gastric surgery. Plasma samples and adipose tissue from both subcutaneous and visceral regions were obtained. Plasma adiponectin and adipose adiponectin expression were analyzed. Results Adiponectin mRNA expression in the subcutaneous tissue was significantly higher (P = 0.048) than in visceral tissue. Circulating adiponectin values, were positively associated with the proportion of n-3 polyunsaturated fatty acids in plasma (r = 0.62, P = 0.002). The visceral depot showed greater statistical associations between adiponectin gene expression and fatty acids profile, being saturated fatty acids associated with a decrease (r = −0.68, P = 0.015), whereas monounsaturated were related to an increase in this adipose region (r = 0.67, P = 0.017). Conclusions e demonstrated significant associations between adipose tissue adiponectin gene expression and fatty acid composition. These associations were more evident in relation to the visceral depot, an adipose tissue region highly implicated in the metabolic syndrome.     

Subcutaneous and Visceral Adipose Tissue FTO Gene Expression and Adiposity,Insulin Action,Glucose Metabolism,and Inflammatory Adipokines in Type 2 Diabetes Mellitus and in Health

Background  

FTO gene variants are linked to obesity. We tested for site-specific differences in FTO gene expression in subcutaneous and visceral adipose tissue (SAT and VAT, respectively) from individuals with and without type 2 diabetes mellitus (T2D) and the relationships between fasting glucose, in vivo insulin action, and measures of adiposity with FTO gene expression in adipose tissue.     

FTO rs9939609 Gene Polymorphism and Obesity: Lack of Association in Kidney Transplantation

The fat mass and obesity-associated (FTO) gene is one of the most important obesity susceptibility genes. Some FTO gene polymorphisms have been associated with obesity, diabetes, and hypertension, all conditions for which, after transplant, there is increased susceptibility, due to effects of immunosuppressive regimens. To evaluate whether FTO could be a candidate for targeted preventive intervention in the transplant setting, we investigated whether the common genetic variation, FTO rs9939609T>A, could affect weight gain and risk of cardiovascular complications in kidney transplantation.

Dysregulation of the peripheral and adipose tissue endocannabinoid system in human abdominal obesity

The endocannabinoid system has been suspected to contribute to the association of visceral fat accumulation with metabolic diseases. We determined whether circulating endocannabinoids are related to visceral adipose tissue mass in lean, subcutaneous obese, and visceral obese subjects (10 men and 10 women in each group). We further measured expression of the cannabinoid type 1 (CB(1)) receptor and fatty acid amide hydrolase (FAAH) genes in paired samples of subcutaneous and visceral adipose tissue in all 60 subjects. Circulating 2-arachidonoyl glycerol (2-AG) was significantly correlated with body fat (r = 0.45, P = 0.03), visceral fat mass (r = 0.44, P = 0.003), and fasting plasma insulin concentrations (r = 0.41, P = 0.001) but negatively correlated to glucose infusion rate during clamp (r = 0.39, P = 0.009). In visceral adipose tissue, CB(1) mRNA expression was negatively correlated with visceral fat mass (r = 0.32, P = 0.01), fasting insulin (r = 0.48, P < 0.001), and circulating 2-AG (r = 0.5, P < 0.001), whereas FAAH gene expression was negatively correlated with visceral fat mass (r = 0.39, P = 0.01) and circulating 2-AG (r = 0.77, P < 0.001). Our findings suggest that abdominal fat accumulation is a critical correlate of the dysregulation of the peripheral endocannabinoid system in human obesity. Thus, the endocannabinoid system may represent a primary target for the treatment of abdominal obesity and associated metabolic changes.     

Fibronectin Gene Expression in Human Adipose Tissue and Its Associations with Obesity-Related Genes and Metabolic Parameters

Background

Limited data are available on the in vivo expression of fibronectin, one of the main extracellular matrix components. We investigated the expression of fibronectin in abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) and the associations of leptin, adiponectin, and vaspin gene expression with metabolic parameters in obese women.

Methods

We recruited female subjects undergoing bariatric surgery for obesity (n?=?24) and patients undergoing benign gynecological surgery as the control group (n?=?23). We measured anthropometric variables, abdominal fat distribution, metabolic parameters, serum concentrations of leptin, adiponectin, and vaspin, and depot-specific mRNA expression of fibronectin, leptin, adiponectin, and vaspin.

Results

Fibronectin expression in both VAT and SAT was significantly lower in the obese group than in the control group. Fibronectin expression in both VAT and SAT were negatively correlated with body mass index or waist circumference, with higher prominence in VAT. In multiple regression analysis, fibronectin expression in both VAT and SAT was negatively correlated with serum leptin concentration. Fibronectin expression in VAT was negatively correlated with leptin expression in VAT. Additionally, fibronectin expression in SAT was negatively correlated with leptin expression in SAT and positively correlated with adiponectin expression in VAT and SAT.

Conclusions

We found significant negative associations between depot-specific fibronectin expression in human adipose tissue and obesity indices and obesity-related biomarkers. Our results suggest that fibronectin expression may contribute to obesity and metabolic dysregulation in humans.     

Omentin plasma levels and gene expression are decreased in obesity

Central obesity and the accumulation of visceral fat are risk factors for the development of type 2 diabetes and cardiovascular disease. Omentin is a protein expressed and secreted from visceral but not subcutaneous adipose tissue that increases insulin sensitivity in human adipocytes. To determine the impact of obesity-dependent insulin resistance on the regulation of two omentin isoforms, gene expression and plasma levels were measured in lean, overweight, and obese subjects. Omentin 1 was shown to be the major circulating isoform in human plasma. Lean subjects had significantly higher plasma omentin 1 levels than obese and overweight subjects. In addition, higher plasma omentin 1 levels were detected in women compared with men. Plasma omentin 1 levels were inversely correlated with BMI, waist circumference, leptin levels, and insulin resistance as measured by homeostasis model assessment and positively correlated with adiponectin and HDL levels. Both omentin 1 and omentin 2 gene expression were decreased with obesity and were highly correlated with each other in visceral adipose tissue. In summary, decreased omentin levels are associated with increasing obesity and insulin resistance. Therefore, omentin levels may be predictive of the metabolic consequences or co-morbidities associated with obesity.     

Downregulation of electron transport chain genes in visceral adipose tissue in type 2 diabetes independent of obesity and possibly involving tumor necrosis factor-alpha

Impaired oxidative phosphorylation is suggested as a factor behind insulin resistance of skeletal muscle in type 2 diabetes. The role of oxidative phosphorylation in adipose tissue was elucidated from results of Affymetrix gene profiling in subcutaneous and visceral adipose tissue of eight nonobese healthy, eight obese healthy, and eight obese type 2 diabetic women. Downregulation of several genes in the electron transport chain was the most prominent finding in visceral fat of type 2 diabetic women independent of obesity, but the gene pattern was distinct from that previously reported in skeletal muscle in type 2 diabetes. A similar but much weaker effect was observed in subcutaneous fat. Tumor necrosis factor-alpha (TNF-alpha) is a major factor behind inflammation and insulin resistance in adipose tissue. TNF-alpha treatment decreased mRNA expression of electron transport chain genes and also inhibited fatty acid oxidation when differentiated human preadipocytes were treated with the cytokine for 48 h. Thus, type 2 diabetes is associated with a tissue- and region-specific downregulation of oxidative phosphorylation genes that is independent of obesity and at least in part mediated by TNF-alpha, suggesting that impaired oxidative phosphorylation of visceral adipose tissue has pathogenic importance for development of type 2 diabetes.     

Obesity-related Differential Gene Expression in the Visceral Adipose Tissue

Background:This study investigates the expression patterns in human adipose tissue, and identifies genes that may be involved in the abnormal energy homeostasis. Methods: Subjects were prospectively recruited from morbidly obese patients undergoing bariatric surgery and from non-obese organ donors. Extensive clinical data and visceral fat specimens were obtained from each subject at the time of surgery. A group of 50 obese patients and 9 non-obese controls were selected for further study. Two custom two-color cDNA microarrays were produced with 40,173 human individual cDNA clones. Microarray experiments were performed for each sample, and a selected group of gene expression values were confirmed with real-time RT-PCR. Results: A comparison of gene expression profiles from obese and non-obese patients identified 1,208 genes with statistically significant differential expression between the 2 groups. Most prominent among these genes are multiple glycolysis enzyme encoding genes; others are involved in oxysterol biosynthesis and signaling, or are ATP-binding transporters and solute carriers. Conclusion: Differential gene expression in the adipose tissue of morbidly obese patients includes genes related to lipid and glucose metabolism, membrane transport, and genes promoting the cell cycle. These findings are a first step toward clarifying the molecular pathogenesis of obesity and identifying potential targets for therapeutic intervention.     

Effects of RS9939609 Gene Variant in FTO Gene on Weight Loss and Cardiovascular Risk Factors After Biliopancreatic Diversion Surgery

Background

The high variation in responses to bariatric surgery might be partially explained by genetic effects. Recently, common polymorphisms of the fat mass and obesity-associated gene (FTO) have been linked to obesity in some populations. Only two studies have investigated the effect of FTO variants on weight loss of morbid obese patients undergoing bariatric surgery with contradictory results.

Objective

We decided to investigate the role of the rs9939609 FTO gene polymorphism on outcomes after a biliopancreatic diversion surgery (BPD) in morbidly obese patients.

Design

A sample of 119 morbidly obese patients' body mass index (BMI)?>?40?kg/m² were operated. Weight, fat mass, blood pressure, basal glucose, triacylglycerols, total cholesterol, low density lipoprotein cholesterol and high density lipoprotein cholesterol were measured at basal visit and at each visit (basal, 3, 9 and 12?months). The frequency of metabolic comorbidities was recorded at each visit.

Results

Thirty-seven patients (31.1%) had genotype TT (wild type group), 58 (48.7%) patients had genotype TA and 24 patients (20.2%) had genotype AA. In the wild and mutant type groups, BMI, weight, waist circumference, systolic blood pressure and diastolic blood pressure decreased in a significant way. In the wild type groups, glucose, total cholesterol, low density lipoprotein (LDL) cholesterol and triacylglycerol concentrations decreased at 3, 9 and 12?months after surgery. In the mutant type groups, glucose, total cholesterol and triacylglycerol concentrations decreased at 3, 9 and 12?months after surgery. LDL cholesterol decreased at 9 and 12?months after surgery. Initial weight percent loss at 3?months of follow-up was higher in the wild type group (26.1% vs. 18.6%: p?Conclusion Our study showed a higher initial weight loss at 3?months after the TT variant of FTO gene (rs9939609). However, the weight loss at 9 and 12?months of BPD was similar in both genotypes with a significant improvement in biochemical parameters and cardiovascular comorbidities.     

Regulation of the Fibrosis and Angiogenesis Promoter SPARC/Osteonectin in Human Adipose Tissue by Weight Change, Leptin, Insulin, and Glucose

OBJECTIVE

Matricellular Secreted Protein, Acidic and Rich in Cysteine (SPARC), originally discovered in bone as osteonectin, is a mediator of collagen deposition and promotes fibrosis. Adipose tissue collagen has recently been found to be linked with metabolic dysregulation. Therefore, we tested the hypothesis that SPARC in human adipose tissue is influenced by glucose metabolism and adipokines.

RESEARCH DESIGN AND METHODS

Serum and adipose tissue biopsies were obtained from morbidly obese nondiabetic subjects undergoing bariatric surgery and lean control subjects for analysis of metabolic markers, SPARC, and various cytokines (RT-PCR). Additionally, 24 obese subjects underwent a very-low-calorie diet of 1,883 kJ (450 kcal)/day for 16 weeks and serial subcutaneous-abdominal-adipose tissue (SCAT) biopsies (weight loss: 28 ± 3.7 kg). Another six lean subjects underwent fast-food–based hyperalimentation for 4 weeks (weight gain: 7.2 ± 1.6 kg). Finally, visceral adipose tissue explants were cultured with recombinant leptin, insulin, and glucose, and SPARC mRNA and protein expression determined by Western blot analyses.

RESULTS

SPARC expression in human adipose tissue correlated with fat mass and was higher in SCAT. Weight loss induced by very-low-calorie diet lowered SPARC expression by 33% and increased by 30% in adipose tissue of subjects gaining weight after a fast-food diet. SPARC expression was correlated with leptin independent of fat mass and correlated with homeostasis model assessment–insulin resistance. In vitro experiments showed that leptin and insulin potently increased SPARC production dose dependently in visceral adipose tissue explants, while glucose decreased SPARC protein.

CONCLUSIONS

Our data suggest that SPARC expression is predominant in subcutaneous fat and its expression and secretion in adipose tissue are influenced by fat mass, leptin, insulin, and glucose. The profibrotic effects of SPARC may contribute to metabolic dysregulation in obesity.Secreted Protein, Acidic and Rich in Cysteine (SPARC), a 34-kDa matricellular glycoprotein, is also known as osteonectin and BM-40. It was initially found to be secreted from bone (1), but SPARC is expressed in most tissues and was the first extracellular matrix protein described in adipose tissue (2,3).SPARC is a multifunctional protein: it is involved in osteogenesis, angiogenesis, wound healing, tumorigenesis, and the pathogenesis of fibrosis involving the kidney (4,5) and liver (6). SPARC also contributes to collagen fibril formation in the dermis, and SPARC knockout mice have reduced collagen content in the dermis (7). More recent evidence suggests that fibrosis in adipose tissue impairs metabolic function and reduces the capacity of fat expansion (3). SPARC is secreted from human adipose tissue and is predominantly derived from adipocytes, where it has a role in adipocyte differentiation, adipogenesis, and adipose tissue hyperplasia (2,8); however, it is unknown whether SPARC contributes to the pathogenesis of insulin resistance or the metabolic syndrome. The aim of this study was therefore to study 1) the depot-specific expression of SPARC, 2) the association of SPARC with markers of insulin resistance, 3) the association of SPARC adipose tissue expression with the adipokines leptin and adiponectin, and 4) the effect of weight loss and weight gain on adipose tissue SPARC expression.We determined the adipose tissue depot expression in visceral fat (VAT) and subcutaneous abdominal adipose tissue (SCAT) in lean and morbidly obese subjects in association with adipokine levels and markers of insulin resistance and explored the gene expression of SPARC in a longitudinal intervention study involving obese subjects treated with a very-low-calorie diet (VLCD) to induce weight loss. Cell culture studies confirmed the regulation of SPARC by insulin, glucose, and leptin.     

高脂饮食小鼠脂肪组织中PAI-1、FOXC2及FOXO1表达的研究

目的：研究高脂饮食喂养小鼠内脏脂肪和皮下脂肪组织中PAI-1、FOXC2及FOXO1表达水平,探讨不同类型肥胖的机制。方法20只小鼠随机分为对照组和高脂组,分别给予正常饮食和高脂饮食喂养12周。测定血清PAI-1以及附睾周围组织及皮下脂肪中PAI-1、FOXC2及FOXO1 mRNA的表达水平。结果高脂组小鼠体质量、血清PAI-1水平均显著高于对照组。组内比较小鼠附睾周围脂肪组织PAI-1、FOXC2mRNA表达显著高于皮下脂肪组织;FOXO1mRNA表达显著低于于皮下脂肪组织,差异有统计学意义。结论正常体重小鼠和肥胖小鼠血清PAI-1水平表达不同,内脏脂肪和皮下脂肪PAI-1、FOXC2及FOXO1表达也存在差别,这种差别可能是不同类型肥胖的机制之一。     

Differential responses of visceral and subcutaneous fat depots to nutrients

Increased visceral adiposity is a pivotal component of the metabolic syndrome. Differential gene expression patterns of fat-derived peptides (FDPs) in visceral fat and subcutaneous fat have been characterized in the fasting state. Here we examined whether delivery of nutrients differentially affects the expression of FDPs in visceral fat versus subcutaneous fat (in the fed state). We increased the rate of glucose flux into adipose tissue of normal rats (n = 16) by hyperglycemia or hyperinsulinemia using the clamp technique. Glucose uptake was associated with increased expression of FDPs, including resistin ( approximately 5-fold), adiponectin ( approximately 2-fold), leptin ( approximately 15-fold), plasminogen activating inhibitor-1 ( approximately 10-fold), and angiotensinogen ( approximately 4-fold) in visceral fat, but markedly less in subcutaneous fat. Cytokine expression derived mainly from vascular/stromal/macrophage components of adipose tissue was less dramatically increased. Infusion of glucosamine amplified the results obtained by increasing glucose uptake into adipose tissue, suggesting that flux through the hexosamine biosynthetic pathway may serve as a mechanism for "nutrient sensing." Nutrient-dependent expression of FDPs in visceral fat was also associated with increased plasma levels of several FDPs. Because a biologic sensing pathway can dynamically couple daily food intake to abnormal plasma levels of important FDPs, we challenge the practice of obtaining plasma levels after fasting to assess risk factors for metabolic syndrome.     

Central infusion of histamine reduces fat accumulation and upregulates UCP family in leptin-resistant obese mice

Leptin resistance has recently been confirmed not only in animal obese models but in human obesity. Evidence is rapidly emerging that suggests that activation of histamine signaling in the hypothalamus may have substantial anti-obesity and antidiabetic actions, particularly in leptin-resistant states. To address this issue, effects of central, chronic treatment with histamine on food intake, adiposity, and energy expenditure were examined using leptin-resistant obese and diabetic mice. Infusion of histamine (0.05 pmol x g body wt(-1) x day(-1)) into the lateral cerebroventricle (i.c.v.) for 7 successive days reduced food intake and body weight significantly in both diet-induced obesity (DIO) and db/db mice. Histamine treatment reduced body fat weight, ob gene expression, and serum leptin concentration more in the model mice than in pair-fed controls. The suppressive effect on fat deposition was significant in visceral fat but not in subcutaneous fat. Serum concentrations of glucose and/or insulin were reduced, and tests for glucose and insulin tolerance showed improvement of insulin sensitivity in those mice treated with histamine compared with pair-fed controls. On the other hand, gene expression of uncoupling protein (UCP)-1 in brown adipose tissue and UCP-3 expression in white adipose tissue were upregulated more in mice with i.c.v. histamine infusion than in the pair-fed controls. These upregulating effects of histamine were attenuated by targeted disruption of the H1-receptor in DIO and db/db mice. Sustained i.c.v. treatment with histamine thus makes it possible to partially restore the distorted energy intake and expenditure in leptin-resistant mice. Together, i.c.v. treatment with histamine contributes to improvement of energy balance even in leptin-resistant DIO and db/db mice.     

Liver upregulation of genes involved in cortisol production and action is associated with metabolic syndrome in morbidly obese patients

Background  

Hepatic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity, which converts cortisone (inactive) to cortisol, is downregulated in obesity. However, this compensation fails in obese with metabolic abnormalities, such as diabetes. To further characterize the tissue-specific cortisol regeneration in obesity, we have investigated the mRNA expression of genes related to local cortisol production, i.e., 11β-HSD1, hexose-6-phosphate dehydrogenase (H6PDH) and cortisol action, glucocorticoid receptor (GR) and a cortisol target gene, phosphoenolpyruvate carboxykinase (PEPCK) in the liver, and visceral (VAT) and subcutaneous (SAT) adipose tissues from morbidly obese patients with and without metabolic syndrome (MS).     

Plasma leptin and insulin levels in weight-reduced obese women with normal body mass index: relationships with body composition and insulin.

Obesity is a complex disease with multiple features that has confounded efforts to unravel its pathophysiology. As a means of distinguishing primary from secondary characteristics, we compared levels of fasting plasma leptin and insulin in a cohort of weight-reduced obese women who have attained and maintained a normal BMI for more than 1 year with the levels in cohorts of never-obese and currently obese women. Weight-reduced obese women showed decreased plasma concentrations of leptin and insulin compared with obese women, but these levels remained significantly higher than those of never-obese women. Plasma leptin levels were highly correlated with plasma insulin levels (r = 0.60, P < 0.001). To further explore relationships with body composition, total body fat was determined by dual-energy X-ray absorptiometry and body fat distribution by computed tomography in subsets of these groups. Weight-reduced obese women had a significantly greater percent body fat and subcutaneous abdominal fat mass than did the never-obese women, and these were highly correlated with plasma leptin (r = 0.90, P < 0.001, and r = 0.52, P < 0.001, respectively). In these weight-reduced obese women, visceral fat mass was similar to that of the never-obese. The insulin sensitivity index and first-phase insulin response were also comparable. These results demonstrate that higher leptin levels in weight-reduced obese women are related to the higher total fat and particularly the subcutaneous fat masses. Normalization of visceral fat mass in the weight-reduced obese was accompanied by normalization of insulin sensitivity index and first-phase insulin response. This study suggests that increases in plasma leptin and insulin in obesity are secondary features of the obese state.