Chronic energy surplus increases body fat, leading to obesity. Since obesity is closely associated with most metabolic complications, pathophysiological roles of adipose tissue in obesity have been intensively studied. White adipose tissue is largely divided into subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT). These two white adipose tissues are similar in their appearance and lipid storage functions. Nonetheless, emerging evidence has suggested that SAT and VAT have different characteristics and functional roles in metabolic regulation. It is likely that there are intrinsic differences between VAT and SAT. In diet-induced obese animal models, it has been reported that adipogenic progenitors in VAT rapidly proliferate and differentiate into adipocytes. In obesity, VAT exhibits elevated inflammatory responses, which are less prevalent in SAT. On the other hand, SAT has metabolically beneficial effects. In this review, we introduce recent studies that focus on cellular and molecular components modulating adipogenesis and immune responses in SAT and VAT. Given that these two fat depots show different functions and characteristics depending on the nutritional status, it is feasible to postulate that SAT and VAT have different developmental origins with distinct adipogenic progenitors, which would be a key determining factor for the response and accommodation to metabolic input for energy homeostasis.
Adipocytes ; Adipogenesis ; Adipose Tissue ; Adipose Tissue, White ; Energy Metabolism ; Hand ; Homeostasis ; Inflammation ; Intra-Abdominal Fat ; Models, Animal ; Nutritional Status ; Obesity ; Stem Cells ; Subcutaneous Fat

PURPOSE: It has been generally recognized that fatty liver can often be seen in the obese population. This study was conducted in order to evaluate the association between fatty liver and abdominal fat volume. MATERIALS AND METHODS: A total of 105 patients who visited our obesity clinic in the recent three years underwent fat CT scans and abdominal US. Attenuation difference between liver and spleen on CT was considered as a reference standard for the diagnosis of fatty liver. On US, the echogenicity of the liver parenchyma was measured in three different regions of interest (ROI) close to the adjacent right kidney in the same slice, avoiding vessels, bile duct, and calcification. Similar measurements were performed in the right renal cortex. The mean values were calculated automatically on the histogram of the ROI using the PACS program. The hepatorenal echogenicity ratio (HER; mean hepatic echogenicity/mean renal echogenicity) was then calculated. Abdominal fat volume was measured using a 3 mm slice CT scan at the L4/5 level and was calculated automatically using a workstation. Abdominal fat was classified according to total fat (TF), visceral fat (VF), and subcutaneous fat (SF). We used Pearson's bivariate correlation method for assessment of the correlation between HER and TF, VF, and SF, respectively. RESULTS: Significant correlation was observed between HER and abdominal fat (TF, VF, and SF). HER showed significant correlation with VF and TF (r = 0.491 and 0.402, respectively; p = 0.000). The correlation between HER and SF (r = 0.255, p = 0.009) was less significant than for VF or TF. CONCLUSIONS: Fat measurement (HER) by hepatic ultrasound correlated well with the amount of abdominal fat. In particular, the VF was found to show a stronger association with fatty liver than SF.
Abdominal Fat ; Bile Ducts ; Fatty Liver ; Humans ; Intra-Abdominal Fat ; Kidney ; Liver ; Obesity ; Spleen ; Subcutaneous Fat

PURPOSE: Visceral adipose tissue may be strongly linked to increased metabolic risks in adults. However, because little is known regarding the effect of visceral adipose tissue in children and adolescents, we performed this study to determine the association between abdominal fat distribution and metabolic risk factors in this population. METHODS: One hundred one children and adolescents (78 males and 23 females; mean age, 10.8+/-2.4 years) were enrolled. The anthropometric data and metabolic risk factors were evaluated. Theabdominal fat distribution was assessed according to the CT measurement. Age-adjusted, partial correlations were performed among the visceral adipose fat area (VFA), subcutaneous adiposefat area (SFA), metabolic risk factors, and anthropometrics. RESULTS: The SFA increased more rapidly than the VFA with advancing years in both genders. In males, the VFA and SFA were positively correlated with anthropometrics. The VFA was correlated with low HDL-cholesterol and the SFA was correlated with diastolic blood pressure (DBP). However, there was no statistical significance between the VFA, SFA, anthropometrics, and other metabolic risk factors. The VFA and SFA were strongly linked to a number of metabolic risk factors, such as other anthropometrics. CONCLUSION: This study investigated how a low HDL-C was correlated with VFA and how a high DBP was associated with SFA in Korean male children and adolescents. Our results suggest that the correlation between the VFA, SFA, and metabolic risk factors was relatively weak compared to that reported in previous adult studies.
Abdominal Fat ; Adolescent ; Adult ; Blood Pressure ; Child ; Humans ; Intra-Abdominal Fat ; Male ; Obesity ; Risk Factors ; Subcutaneous Fat

PURPOSE: Visceral adipose tissue may be strongly linked to increased metabolic risks in adults. However, because little is known regarding the effect of visceral adipose tissue in children and adolescents, we performed this study to determine the association between abdominal fat distribution and metabolic risk factors in this population. METHODS: One hundred one children and adolescents (78 males and 23 females; mean age, 10.8+/-2.4 years) were enrolled. The anthropometric data and metabolic risk factors were evaluated. Theabdominal fat distribution was assessed according to the CT measurement. Age-adjusted, partial correlations were performed among the visceral adipose fat area (VFA), subcutaneous adiposefat area (SFA), metabolic risk factors, and anthropometrics. RESULTS: The SFA increased more rapidly than the VFA with advancing years in both genders. In males, the VFA and SFA were positively correlated with anthropometrics. The VFA was correlated with low HDL-cholesterol and the SFA was correlated with diastolic blood pressure (DBP). However, there was no statistical significance between the VFA, SFA, anthropometrics, and other metabolic risk factors. The VFA and SFA were strongly linked to a number of metabolic risk factors, such as other anthropometrics. CONCLUSION: This study investigated how a low HDL-C was correlated with VFA and how a high DBP was associated with SFA in Korean male children and adolescents. Our results suggest that the correlation between the VFA, SFA, and metabolic risk factors was relatively weak compared to that reported in previous adult studies.
Abdominal Fat ; Adolescent ; Adult ; Blood Pressure ; Child ; Humans ; Intra-Abdominal Fat ; Male ; Obesity ; Risk Factors ; Subcutaneous Fat

Obesity was characterized in Korean elementary students using different obesity assessment tests on 103 overweight elementary students from three schools of Jeonbuk Province. The body mass index (BMI) and obesity index (OI) were compared, and the data using DEXA and CT were compared with the data using BIA and a tape measure. The results of this study are as follows: first, 27 students who were classified as obese by OI were classified as overweight by BMI, and 3 students who were classified as standard weight by BMI were classified as overweight by OI. Secondly, by DEXA and BIA measurements, there was 1.51% difference in body fat percentage (boys 1.66%, girls 1.17%) and the difference in body fat mass between boys and girls was 0.77 kg (boys 0.85 kg, girls 0.59 kg), but those differences in body fat percentage and mass were not statistically significant. Thirdly, the average total abdominal fat (TAF) measured by CT scans of obese children was more significantly related with subcutaneous fat (r = 0.983, P < 0.01) than visceral fat (r = 0.640, P < 0.01). Also, TAF were highest significant with waist circumference by a tape measure (r = 0.744, P < 0.01). In summary, as there are some differences of assessment results between two obesity test methods (BMI, OI), we need more definite standards to determine the degree of obesity. The BIA seems to be the most simple and effective way to measure body fat mass, whereas waist/hip ratio (WHR) using a tape measurer is considered to be the most effective method for assessing abdominal fat in elementary students.
Abdominal Fat ; Adipose Tissue ; Anthropometry ; Body Mass Index ; Child ; Humans ; Intra-Abdominal Fat ; Obesity ; Overweight ; Subcutaneous Fat ; Waist Circumference

PURPOSE: We aimed to investigate whether airway parameters, assessed via computed tomography (CT), are associated with abdominal fat areas and to compare the clinical characteristics of asthmatic patients with and without elevated visceral to subcutaneous fat area ratio (EV). METHODS: Asthmatic patients (aged ≥40 years) were prospectively recruited. Chest (airway) and fat areas were assessed via CT. Airway parameters, including bronchial wall thickness (WT), lumen diameter (LD), lumen area (LA), wall area (WA), total area (TA), as well as WA/TA percentage (wall area %) were measured at the apical segmental bronchus in the right upper lobe. Visceral (VFA), subcutaneous (SFA) and total (TFA) fat areas (cm2) were also measured. The correlations between abdominal fat areas and airway parameters were assessed. EV was defined as VFA/SFA ≥ 0.4. RESULTS: Fifty asthmatic patients were included (mean age 62.9 years; 52% female); 38% had severe asthma. Significant correlations were found between VFA and both LD and LA (r = −0.35, P = 0.01; r = −0.34, P = 0.02, respectively), and SFA and both WA and TA (r = 0.38, P = 0.007; r = 0.34, P = 0.02, respectively). Exacerbations, requiring corticosteroid therapy or ER visitation, were significantly more frequent in subjects without EV (83% vs. 34%, P = 0.05). CONCLUSIONS: Abdominal fat is associated with asthma, according to the location of fat accumulation. In asthmatic subjects, visceral fat seems to be attributable to the bronchial luminal narrowing, while subcutaneous fat may be related to thickening of bronchial wall.
Abdominal Fat* ; Asthma ; Bronchi ; Humans ; Intra-Abdominal Fat ; Multidetector Computed Tomography ; Phenobarbital ; Prospective Studies ; Subcutaneous Fat ; Thorax

BACKGROUND: Obesity can be considered as hyperaccumulation of body fat. Therefore, the aim to treat obesity is to decrease body fat. Abdominal total fat calculated in computed tomography is thought to be the most accurate index measuring body fat. The body mass index (BMI) and body fat mass are the representative indices also. Leptin is a protein hormone expressed by obesity gene in adipose tissue. It inhibits food intake and increases energy consumption, thereby controls obesity. With a study of relationship between plasma leptin level and body mass index and abdominal total fat area, we tried to find the usefulness of leptin as an index of adiposity. METHODS: The adiposity level was approximated by BMI, computed tomography and bioelectical impedence. To further explore the relationship with body composition, body fat distribution was determined by computed tomograph. To quantify the relationship between serum leptin level and adiposity, correlation analyses have been conducted. RESULTS: The subjects were 32 females with a BMI of over 25 kg/m2. The mean plasma leptin level was 14.2 5.9 ug/L. We investigated the correlation of plasma leptin level with subcutaneous and visceral fat. The plasma leptin level showed a significant correlation with BMI and body fat mass, and was significantly correlated with subctaneous fat (P<0.01), but not with abdominal visceral fat. CONCLUSION: A significant correlation between plasma leptin level and body fat mass was observed. The distribution of subcutaneous fat showed differences in plasma leptin level. Therefore, the plasma leptin level may be used as an index of change of body fat mass, especially subcutaneous fat.
Adipose Tissue ; Adiposity* ; Body Composition ; Body Fat Distribution ; Body Mass Index ; Eating ; Female ; Humans ; Intra-Abdominal Fat ; Leptin* ; Obesity* ; Plasma* ; Subcutaneous Fat ; Subcutaneous Fat, Abdominal

BACKGROUNDS/AIMS: It has been reported that functional hepatogenic differentiation has the possibility to occur in subcutaneous adipose tissue-derived stem cells. However, no studies have investigated whether the adipose tissue-driven stem cells present in various body parts differ according to hepatogenic differentiations. In this study, stem cells were separated from body visceral fat and abdominal subcutaneous adipose tissue, and cultured, and then hepatogenic differentiation was induced. We aim to investigate the possibilities and aspects of hepatogenic differentiations within the two types of fat cells. METHODS: Omental fat tissues were obtained as visceral fat and abdominal subcutaneous adipose tissues were obtained from patients who had suction-assisted lipectomy. Stem cells were separated from the obtained fat tissues, and then, hepatogenic differentiation was carried out by utilizing 2-step differentiation protocols. RESULTS: After the differentiation, two types of cultured cells that showed the similar neuron-like shapes were changed to cuboidal shapes and included several binucleated cells which could be characteristics of mature hepatocytes. We confirmed that hepatocyte specific genes and proteins such as albumin and CYP3A4 were being expressed. By utilizing the ELISA test, we were able to observe that the albumin was secreted into the culture fluids in both cells. After completing the differentiation, we observed the presence of the hepatocyte specific properties by confirming glycogen storage within the cells and the ICG reagent uptake. CONCLUSIONS: We confirmed that hepatogenic differentiation was possible to occur in the omental fat as well as subcutaneous adipose tissue.
Adipose Tissue ; Cells, Cultured ; Enzyme-Linked Immunosorbent Assay ; Glycogen ; Hepatocytes ; Human Body ; Humans ; Intra-Abdominal Fat ; Lipectomy ; Mesenchymal Stromal Cells ; Proteins ; Stem Cells ; Subcutaneous Fat ; Subcutaneous Fat, Abdominal

OBJECTIVE: Patients with schizophrenia are at a higher risk for developing insulin resistance and type 2 diabetes mellitus (T2DM). However, few studies have examined abdominal fat and mid-thigh low-density muscle areas, which are known risk factors for insulin resistance and T2DM, in patients with schizophrenia. Therefore, we measured the abdominal fat and mid-thigh low-density muscle areas of schizophrenics and compared them with normal controls. METHODS: Nineteen (four men and 15 women) drug-naive or -free subjects who met the DSM IV criteria for schizophrenia and 19 age- and sex-matched controls were recruited. We measured weight, height, waist circumference, and percent body fat, and calculated the body mass index (BMI). Abdominal fat and mid-thigh low-density muscle areas were evaluated using computed tomography. RESULTS: There was no significant difference in terms of age and BMI between the two groups. The areas of abdominal fat (262.4+/-101.8 vs. 257.1+/-93.8 cm2 ; p=0.919), subcutaneous fat (182.4+/-72.8 vs. 180.5+/-75.1 cm2 ; p=0.988), visceral fat (79.9+/-47.2 vs. 76.6+/-49.3 cm2 ; p=0.872), and mid-thigh low-density muscle (15.0+/-9.9 vs. 15.4+/-5.2 cm2, p=0.373) did not differ between schizophrenics and controls. CONCLUSION: Abdominal obesity is a well-recognized risk factor for developing certain medical conditions such as insulin resistance and T2DM. We demonstrated that drug-naive or- free patients with schizophrenia do not have increased visceral fat or mid-thigh low-density muscle areas, which might have explained the higher prevalence of insulin resistance and T2DM in these patients.
Abdominal Fat* ; Adipose Tissue ; Body Mass Index ; Diabetes Mellitus, Type 2 ; Humans ; Insulin Resistance ; Intra-Abdominal Fat ; Male ; Obesity, Abdominal ; Prevalence ; Risk Factors ; Schizophrenia* ; Subcutaneous Fat ; Waist Circumference

BACKGROUND: Obesity is associated with various chronic diseases, especially abdominal fat affect cardiovascular disease, metabolic disease, diabetes mellitus and mortality. The aim of this study was to estimate the accuracy of the visceral fat area measured by bioelectric impedence analysis (BIA) that easily used in many clinical settings, and to compare with the visceral fat area measured by CT and other abdominal obesity measures. METHODS: Participants were 71 premenopausal adult women whose BMI was over 23 kg/m2. BMI, waist circumference, total abdominal fat area, visceral fat area, subcutaneous fat area by CT and truncal fat by dual-energy X-ray absorptiometry (DEXA) were measured. Visceral fat area measured by Inbody 720 were compared with variables examining abdominal obesity using partial correlation analysis and Bland-Altman analysis. The accuracy of the visceral obesity by BIA was compared with that diagnosed by CT as gold standard. RESULTS: There was significant difference between visceral fat area measured by CT and BIA in women below BMI 30 kg/m2, whereas the difference was not significant in women with BMI > or = kg/m2. Visceral fat area measured by BIA was significantly correlated with visceral fat area measured by CT only in subjects with BMI less than 30 kg/m2 after adjusting for age (r = 0.495, P < 0.01). Bland-Altman plot analysis showed a tendency regardless of BMI status; the more visceral fat area increased, the less the difference between two measures. The sensitivity and the specificity to diagnose visceral obesity by BIA was 50.0%, 81.8% respectively among women with BMI less than 30 kg/m2, and 100.0%, 25.0% respectively among women with BMI > or = 30 kg/m2. CONCLUSION: BIA is not appropriate for evaluation of abdominal visceral obesity.
Abdominal Fat ; Absorptiometry, Photon ; Adult ; Cardiovascular Diseases ; Chronic Disease ; Diabetes Mellitus ; Female ; Humans ; Intra-Abdominal Fat ; Metabolic Diseases ; Obesity ; Obesity, Abdominal ; Sensitivity and Specificity ; Subcutaneous Fat ; Waist Circumference