Abdominal Subcutaneous Adipose Research Articles

Gator Circle: A new noninvasive method for evaluating visceral adiposity

Since these risk factors in the pediatric population tend to track into adulthood, early identification is essential. Waist circumference is considered one of the best anthropometric predictors of visceral fat mass and of the Metabolic Syndrome profile. Despite the connection between visceral fat and the metabolic syndrome, there is still no anthropometric measurement that can measure visceral fat mass directly. Current methods of measuring visceral abdominal fat are either inaccurate or too expensive for use in routine clinical settings. The Gator Circle is a new noninvasive and inexpensive method that uses anthropometric measurements to differentiate between visceral and subcutaneous abdominal adiposity. This is achieved by examining the visceral cavity area (VCA), visceral cavity percent (VC%), and waist circumference (WC) Z-score. The visceral cavity area is determined with the use of skinfolds and the umbilical waist circumference (UC). The VC% is the percentage of the total abdominal area found in the visceral cavity. The waist circumference z-score includes the effects of age, gender and race. The Gator Circle is the product of the VC% and the WC Z-score and indicates the size of the visceral cavity relative to a comparison population. Monitoring the Gator Circle with time can be used as an indicator of whether an increasing waist circumference is due to increasing subcutaneous fat, increasing visceral cavity, or an increase in both.

Addition of aerobic exercise to dietary weight loss preferentially reduces abdominal adipocyte size

To determine if hypocaloric diet, diet plus low-intensity exercise, and diet plus high-intensity exercise differentially influence subcutaneous abdominal and gluteal adipocyte size in obese individuals. Longitudinal intervention study of hypocaloric diet, diet plus low-intensity exercise, and diet plus high-intensity exercise (calorie deficit = 2800 kcal/week, 20 weeks). Forty-five obese, middle-aged women (BMI = 33.0+/-0.6 kg/m2, age = 58+/-1 years). Body composition testing and adipose tissue biopsies were conducted before and after the interventions. Subcutaneous abdominal and gluteal adipocyte size was determined. All three interventions reduced body weight, fat mass, percent fat, and waist and hip girths to a similar degree. Diet only did not change subcutaneous abdominal adipocyte size, whereas both diet plus exercise groups significantly reduced abdominal adipocyte size. Changes in abdominal adipocyte size in the diet plus exercise groups were significantly different from that of the diet group. Gluteal adipocyte size decreased similarly in all three groups. Addition of exercise training to dietary weight loss preferentially reduces subcutaneous abdominal adipocyte size in obese women. This may be of importance for the treatment of health complications associated with subcutaneous abdominal adiposity.

Effects Of Strength Training On Visceral And Total Fat Among Women

PURPOSE The SHE study (Strong Healthy and Empowered) seeks to determine the effects of twice-weekly strength training on abdominal and total body fat among overweight and obese (BMI 25–35), generally healthy premenopausal women aged 25–44 at study entry. METHODS Participants were randomized into strength training (n=82) or 'standard care' (n=82) groups. The randomization was stratified by baseline body fat % and age (25–34 vs 35–44). The 'standard care ' group received brochures with the current public health guidelines to be regularly physically active. The strength training group received supervision and instruction for 16 weeks, followed by ongoing behavioral support from certified fitness professionals over 1 year of twice weekly strength training. Participants were asked to avoid dietary changes that would lead to weight changes over the course of the study. All participants underwent measures at baseline and 1 year later, including body composition by DEXA scan and visceral and subcutaneous abdominal adiposity by single slice CT scan at the L2-L3 disk space. RESULTS Attendance to strength training sessions averaged 73% over 1 year of training. Measures revealed no between group differences at baseline. Significant between group differences were noted for 1 year changes in lean mass (p=0.03) and %fat (p=0.04). The between group difference for visceral abdominal fat changes was marginally significant (p =0.07). The treatment group showed a decrease of 3% in total fat and a 4% decrease in visceral abdominal fat stores. CONCLUSIONS Twice weekly strength training is behaviorally feasible. Fat may be lost equally or preferentially from visceral abdominal stores (versus total fat stores) as a result of strength training. Preferential loss of fat from visceral abdominal stores as a result of strength training may have implications for reducing risk for chronic diseases, including diabetes, hypertension, metabolic syndrome, heart disease, and some forms of cancer.Table

Extragonadal aromatization increases with time after ovariectomy in rats

BackgroundThe circulating estrogen concentration elevated gradually along with time after ovariectomy in rats. To explore the source of the increased circulation estrogen, the extragonadal aromatization as well as the synthesis of androgen in the adrenal cortex of the ovariectomized rats was evaluated.MethodsFemale rats were divided into twelve groups: 1 month after ovariectomy (OVX1M), OVX2M, OVX3M, OVX4M, OVX5M, OVX6M; intact 1 month (INT1M), INT2M, INT3M, INT4M, INT5M, INT6M. The blood concentration of testosterone (T) was measured by radioimmunoassay. The mRNA expressions of P450 aromatase in the liver and subcutaneous abdominal (SA) adipose as well as the adrenal cytochrome P450 17 alpha hydroxylase/lyase (P450c17) were semiquantified by RT-PCR. The P450 aromatase protein expressions in the liver and SA adipose were detected by Western blot.ResultsThe blood E2 concentrations increased gradually along with time after ovariectomy in the rats. The 58-kDa aromatase protein and mRNA expressions normalized to β-actin in the OVX6M rats' SA adipose tissues showed higher levels than those from corresponding tissues in the INT6M (p < 0.05). And the ratios of aromatase mRNA and protein to β-actin in the OVX6M rats' liver tissues increased significantly compared with those in the OVX1M rats (p < 0.05). The ratio of adrenal P450c17 to beta-actin in the OVX6M increased markedly, and was higher than OVX1M (p < 0.05), though the blood concentration of T decreased significantly in all the ovariectomized rats (p < 0.05).ConclusionBoth the subcutaneous abdominal adipose tissues and the liver tissues contributed to the extragonadal aromatisation to promote the circulating E2 levels in the rats along with time after ovariectomy; the adrenal compensation might also be activated naturally.

Electroacupuncture enhances extragonadal aromatization in ovariectomized rats

BackgroundRepeated electroacupuncture (EA) stimulation is known to stimulate the activity of the hypothalamus-pituitary-adrenal axis, and to enhance the circulation level of estrogen in the ovariectomized rats. To explore the source of the increased circulation estrogen, the extragonadal aromatization was detected.MethodsFemale rats were divided into five groups: 1) intact (INT), 2) intact with EA in specific points (INT+EA), 3) ovariectomized (OVX), 4) ovariectomized with EA in specific points (OVX+EA) and 5) ovariectomized with EA in non-specific points (OVX+C). Radiometric assay, Western blot and RT-PCR were adopted to determine the extragonadal aromatization in subcutaneous abdominal (SA) adipose and liver tissues of rats. The blood concentrations of estrogen, testosterone and corticosterone were measured by radioimmunoassay.ResultsThe aromatase activities of the SA adipose and liver tissues in the OVX+EA rats increased significantly (p < 0.01) compared with those in the INT, INT+EA and OVX rats. The 58-kDa aromatase protein and aromatase mRNA expressions normalized to β-actin in the OVX+EA rats' SA adipose tissues showed higher levels than those from corresponding tissues in the INT and INT+EA rats (p < 0.05). And the ratios of aromatase mRNA and protein to β-actin in the OVX+EA rats' liver tissues increased significantly compared with those in the OVX rats (p < 0.05). Furthermore, blood estrogen and corticosterone concentrations showed significant increase in the OVX+EA rats compared with the concentrations in the OVX and OVX+C rats (p < 0.05), but no statistical disparity occurred on the blood testosterone concentrations between the OVX+EA rats and the OVX ones.ConclusionBoth the subcutaneous abdominal adipose and the liver tissues contributed to the effects of electroacupuncture on the extragonadal aromatization to promote the blood concentrations of estrogen in the ovariectomized rats.

Insulin resistance of puberty in African-American children: lack of a compensatory increase in insulin secretion.

Type 2 diabetes has been increasing in children, mostly affecting minority populations at around the age of puberty. Despite a multitude of studies demonstrating pubertal insulin resistance/hyperinsulinemia in white children, data are almost non-existent in African-American children. The aim of the present study was to investigate the impact of puberty on glucose metabolism, insulin sensitivity and secretion in African-American children. Twenty prepubertal and 16 pubertal African-American subjects participated. All underwent a 3-h hyperinsulinemic (40 mU/m(2)/min) euglycemic clamp to determine insulin-stimulated glucose disposal, and a 2-h hyperglycemic (12.5 mmol/L) clamp to assess first- and second-phase insulin secretion. Body composition was assessed by dual energy X-ray absorptiometry (DEXA) and visceral and subcutaneous abdominal adiposity with computed tomography (CT) scan at L4-L5. Total glucose disposal, glucose oxidation and non-oxidative glucose disposal were significantly lower in the pubertal group compared with the prepubertal one (53.8 +/- 3.9 vs. 72.2 +/- 5.0 micromol/kg/min, p = 0.009; 23.3 +/- 1.1 vs. 31.6 +/- 1.7 micromol/kg/min, p = 0.001; and 30.0 +/- 3.3 vs. 40.5 +/- 3.9 micromol/kg/min, p = 0.049, respectively). Insulin sensitivity was approximately 30% lower in the adolescents compared with the prepubertal children. However, first- and second-phase insulin secretions were not different between the two groups (971.4 +/- 180.6 vs. 1044.0 +/- 191.4 pmol/L and 999.6 +/- 159.6 vs. 955.8 +/- 142.2 pmol/L, respectively). In conclusion, despite approximately 30% lower insulin sensitivity in African-American adolescents compared with prepubertal children, insulin secretion is not higher. This is in contrast to published findings in white children in whom insulin secretion is higher during puberty. These racial differences in physiologic adaptation to puberty could play a role in the higher prevalence of type 2 diabetes in African-American children at the time of puberty.

Subdivisions of subcutaneous abdominal adipose tissue and insulin resistance.

Whereas truncal (central) adiposity is strongly associated with the insulin resistant metabolic syndrome, it is uncertain whether this is accounted for principally by visceral adiposity (VAT). Several recent studies find as strong or stronger association between subcutaneous abdominal adiposity (SAT) and insulin resistance. To reexamine the issue of truncal adipose tissue depots, we performed cross-sectional abdominal computed tomography, and we undertook the novel approach of partitioning SAT into the plane superficial to the fascia within subcutaneous adipose tissue (superficial SAT) and that below this fascia (deep SAT), as well as measurement of VAT. Among 47 lean and obese glucose-tolerant men and women, insulin-stimulated glucose utilization, measured by euglycemic clamp, was strongly correlated with both VAT and deep SAT (r = -0.61 and -0.64, respectively; both P < 0.001), but not with superficial SAT (r = -0.29, not significant). Also, VAT and deep SAT followed a highly congruent pattern of associations with glucose and insulin area under the curve (75-g oral glucose tolerance test), mean arterial blood pressure, apoprotein-B, high-density lipoprotein cholesterol, and triglyceride. Superficial SAT had markedly weaker association with all these parameters and instead followed the pattern observed for thigh subcutaneous adiposity. We conclude that there are two functionally distinct compartments of adipose tissue within abdominal subcutaneous fat and that the deep SAT has a strong relation to insulin resistance.

Microdialysis assessment of local adipose tissue lipolysis during beta-adrenergic stimulation in upper-body-obese subjects with type II diabetes.

The present study was designed to investigate indicators of abdominal adipose tissue lipolysis (microdialysis), and subcutaneous adipose tissue blood flow and whole-body lipolysis, in obesity-associated type II diabetes during overnight-fasted conditions (baseline) and during intravenous infusion of the non-selective beta-agonist isoprenaline. Basal subcutaneous adipose tissue blood flow and isoprenaline-induced increases in adipose tissue blood flow were not significantly different between subjects with type II diabetes and non-obese, non-diabetic controls. Adipose tissue interstitial glycerol concentrations were significantly higher in subjects with type II diabetes compared with controls (P<0. 01), and during isoprenaline infusion there was a decrease in interstitial glycerol in both groups (P<0.001). Arterial glycerol concentrations were higher in subjects with type II diabetes compared with controls (P<0.05), whereas the increases in arterial glycerol concentration in response to isoprenaline infusion were of a similar magnitude in the two groups. Estimated subcutaneous adipose tissue glycerol release was not significantly different between the groups (controls and subjects with type II diabetes: baseline, -129+/-32 and -97+/-72 micromol.min(-1).100 g(-1) adipose tissue respectively; isoprenaline, -231+/-76 and -286+/-98 micromol. min(-1).100 g(-1) respectively). Values for fat oxidation were not significantly different between groups, whereas the isoprenaline-induced increase in fat oxidation tended to be less pronounced in subjects with type II diabetes compared with controls (0.022+/-0.008 and 0.038+/-0.003 g/min respectively; P=0.058). Thus estimated basal subcutaneous adipose tissue glycerol release, expressed per unit of fat mass, is not different in controls and in subjects with type II diabetes. Additionally, the isoprenaline-induced increases in indicators of local abdominal subcutaneous adipose tissue, systemic lipolysis and abdominal adipose tissue blood flow responses were comparable in obese subjects with type II diabetes and in controls. The last two findings contrast with previous data from obese subjects, indicating that the regulation of lipolysis may differ in obesity and obesity-associated type II diabetes.

Expression of Types 1, 2, and 3 17 -Hydroxysteroid Dehydrogenase in Subcutaneous Abdominal and Intra-Abdominal Adipose Tissue of Women

Expression of Types 1, 2, and 3 17 -Hydroxysteroid Dehydrogenase in Subcutaneous Abdominal and Intra-Abdominal Adipose Tissue of Women

Protein metabolism in human obesity: relationship with glucose and lipid metabolism and with visceral adipose tissue.

It is controversial whether metabolic disorders of human obesity include protein metabolism. Even less information is available concerning the effect of fat distribution on protein metabolism. Therefore, a comprehensive evaluation of glucose, lipid, and protein metabolism was performed in 11 obese nondiabetic and 9 normal women whose body composition and regional fat distribution were determined. [1-14C]Leucine and [3-3H]glucose were infused in the postabsorptive state and during an euglycemic hyperinsulinemic (35-40 microU/mL) clamp combined with indirect calorimetry for assessment of leucine flux, oxidation, and nonoxidative disposal, glucose turnover and oxidation, and lipid oxidation. Fat-free mass (FFM) was estimated by a bolus of 3H2O. Subcutaneous abdominal and visceral adipose tissues were determined by nuclear magnetic resonance imaging. During the clamp, obese women had lower glucose turnover (4.51 +/- 0.41 vs. 6.63 +/- 0.40 mg/min.kg FFM; P < 0.05), with a defect in both oxidation (3.27 +/- 0.22 vs. 3.89 +/- 0.21) and nonoxidative disposal (1.24 +/- 0.27 vs. 2.74 +/- 0.41; P < 0.005), whereas lipid oxidation was higher during the clamp (0.49 +/- 0.15 vs. 0.17 +/- 0.09 mg/min.kg FFM). There was no difference in leucine flux (basal, 2.23 +/- 0.17 vs. 2.30 +/- 0.29; clamp, 2.06 +/- 0.19 vs. 2.10 +/- 0.24 mumol/min.kg FFM), oxidation (basal, 0.37 +/- 0.04 vs. 0.36 +/- 0.05; clamp, 0.34 +/- 0.04 vs. 0.39 +/- 0.06) and nonoxidative leucine disposal (basal, 1.86 +/- 0.17 vs. 1.94 +/- 0.26; clamp, 1.72 +/- 0.20 vs. 1.71 +/- 0.19) in the two groups. In obese women, basal leucine oxidation was directly related with glucose oxidation and inversely to lipid oxidation (both P < 0.05), whereas visceral adipose tissue was inversely related to leucine flux both in the basal state and during the clamp (P < 0.05). In conclusion, in human obesity, 1) rates of protein metabolism in the basal state and in the range of insulin concentrations encountered after a meal are normal; 2) protein oxidation is positively related to glucose oxidation and negatively related to lipid oxidation; and 3) visceral adipose tissue is inversely related to all parameters of protein metabolism.

Isolation, Culture and Identification of Human Microvascular Endothelial Cells: A Comparison of Abdominal Subcutaneous and Omental Adipose Tissue

The isolation and characterisation of human microvascular endothelial cells from adipose tissue is described and a comparison is made between isolations from abdominal subcutaneous and omental adipose tissue. Microvascular cells were isolated by incubating finely chopped material in (i) collagenase type II solution, followed by density gradient centrifu-gation and further incubation in trypsin, or in (ii) collagenase type II solution, followed by trypsin incubation and selective filtration. The final step in both procedures was selection using Ulex europaeus agglutinin-1 coated Dynabeads. The cells were characterised using immunocytochemical and biochemical techniques. The cells exhibited characteristic staining for antigens recognised by antibodies against von Willebrand factor and platelet-endothelial cell adhesion molecule (PECAM-I). They also expressed angiotensin-converting enzyme and internalised acetylated low-density lipoprotein.

Comparison of two methods to assess the tissue/blood partition coefficient for xenon in subcutaneous adipose tissue in man

A new method to calculate the tissue/blood partition coefficient (lambda) for xenon in studies on the subcutaneous adipose tissue blood flow was compared with a previously reported method based on local skinfold thickness (lambda LST). The former method included needle biopsies from the abdominal and femoral subcutaneous adipose tissue, and the mean fat cell diameter was measured (lambda ECT). The extracellular tissue fraction in subcutaneous tissue was then estimated from a diagram. The tissue lipid content was approximated to equal the relative intracellular volume and Ostwald's solubility coefficients for 133Xe, based on the distribution of xenon in lipid, albumin and 0.9% saline were applied. Estimated lambda-values based on needle biopsies from the abdominal site were: 8.6 +/- 0.1 versus 9.9 +/- 0.4 ml g-1 (mean +/- SE) (P < 0.05) and from the femoral site: 9.1 +/- 0.1 versus 9.6 +/- 0.2 in lean (n = 10) and obese subjects (n = 10), respectively. The corresponding lambda-values obtained from skinfold measurements were: 6.2 +/- 0.5 versus 11.0 +/- 0.4 (P < 0.001) and 6.9 +/- 0.3 versus 11.4 +/- 0.4 (P < 0.001) in lean and obese subjects, respectively. Pooled lambda LST-values correlated positively with estimated adipose tissue blood flow (ATBF) (r: 0.34, P < 0.05, n = 40) whereas no such correlation was found for lambda ECT-values. In conclusion, a new method is presented which may allow an accurate determination of, and which may lead to reliable data on, subcutaneous ATBF in both lean and obese subjects.(ABSTRACT TRUNCATED AT 250 WORDS)