Search

Background: Modifications in body fat in obese patients during puberty determine changes in adipokines that affect insulin sensitivity., Aims: We hypothesized that the leptin/adiponectin (L/A) ratio and free leptin index (FLI) are good markers of insulin resistance (IR) and total body fat (TBF) during pubertal development., Methods: A prospective study of 32 obese girls (OG) and age-matched control girls (CG) was performed. OG were divided into those that maintained a weight loss (WL) of >1 SD of initial body mass index (BMI) (WL group, n = 25) and those without WL (NWL group, n = 7). Oral glucose tolerance tests (OGTT) were performed to evaluate IR. Correlations of adipokines, L/A, and FLI with BMI, waist circumference, percentage of TBF (%TBF) and IR were performed over pubertal development., Results: The L/A ratio and FLI were increased in OG at baseline. Both indexes decreased in the WL group as puberty progressed, with no change in CG or NWL. In the WL group, a correlation between L/A and FLI with OGTT and %TBF, and L/A and homeostasis model assessment (HOMA) was found throughout the study., Conclusion: The L/A ratio and FLI are good markers to follow changes in IR and %TBF after WL during puberty. Insulin more accurately reflects the changes in IR than HOMA.

Objective: To investigate the impact of obesity, weight loss and oral glucose ingestion on serum visfatin and vaspin levels in prepubertal children., Subjects and Methods: A total of 100 prepubertal obese Caucasian children (OB) and 42 controls (C) were studied. The OB group was studied at baseline and after moderate (n=46) and extensive (n=14) body mass index (BMI) reduction by conservative treatment, undergoing body composition studies (dual-energy X-ray absorptiometry) and oral glucose tolerance tests (OGTTs). Serum visfatin and vaspin levels were studied throughout the OGTT, as were their relationships with insulin, leptin, leptin soluble receptor (sOB-R), adiponectin (total and high molecular weight), resistin, interleukin-6 (IL-6) and tumor necrosis factor-α levels at every time point., Results: OB had higher visfatin (P<0.001), but similar vaspin than C. BMI reduction decreased visfatin levels (P<0.001), with BMI, waist circumference and the surrogate markers of body fat (leptin and sOB-R) showing significant correlations (P<0.05) with this peptide, but not with vaspin. Visfatin and vaspin decreased during the OGTT (P<0.001). Weight reduction did not alter visfatin dynamics in the OGTT, but decreased the area under the curve (AUC) for vaspin (P<0.001), with a correlation between the AUCs for vaspin and insulin after weight loss (P<0.05). Visfatin levels were positively correlated with resistin and IL-6, after controlling for BMI and HOMA (homeostatic model assessment) index at every time point in the study., Conclusion: Serum visfatin, but not vaspin, levels are influenced by body fat content in obese children, whereas both adipokines are modulated by glucose intake in a BMI-dependent manner.

Background: Ghrelin isoforms are involved in energy homeostasis and carbohydrate metabolism., Aim: To determine the influence of oral glucose ingestion and weight reduction on acylated ghrelin (AG) serum levels and on the AG to total ghrelin (TG) ratio (AG/TGr) in obese pre-pubertal children., Subjects and Methods: Seventy obese children were studied at diagnosis (D) and after reduction of their body mass index (BMI) of over 1 (-1; no.=51) and 2 SD score (-2; no.=21). Body composition was analyzed and serum levels of glucose, insulin, TG and AG, and the AG/TGr were determined at every time-point in an oral glucose tolerance test (OGTT) at D and at -2. The control group consisted of 32 lean children., Results: At D AG and TG levels were lower in obese children and negatively correlated with BMI. TG levels were negatively correlated with the homeostasis model assessment (HOMA) index in the whole cohort, as with the body fat content (BFC) in the obese patients. Weight loss exclusively reduced BFC and improved HOMA, increasing AG transiently and TG sustainedly, with AG/TGr exclusively decreasing at -2. Glucose ingestion caused a sustained increase in AG and decrease in TG, thus increasing the AG/TGr throughout the entire OGTT; this remained unaltered after weight reduction., Conclusions: TG and AG levels are influenced by BMI, showing an impairment in childhood obesity that can be improved through weight loss. The different fractions of ghrelin appear to play different roles in carbohydrate metabolism and the calculation of AG/TGr could be useful in the follow up of childhood obesity.

Our aim was to determine the influence of weight reduction on total (T-) and high-molecular weight (HMW-) adiponectin in obese (OB) prepubertal children. Seventy OB prepubertal white patients were followed for 18 months and studied after reducing their BMI by 1 (n = 51) and 2 standard deviation scores (SDS) (n = 21) under conservative treatment, and 6 months after achieving weight loss (n = 44). Body composition dual-energy X-ray absorptiometry (DXA) and serum levels of T- and HMW-adiponectin, resistin, leptin, leptin soluble receptor (sOB-R), tumoral necrosis factor-α and interleukin-6 were determined. The control group consisted of 61 healthy prepubertal children. At diagnosis T-adiponectin was higher (P < 0.01; confidence interval (+0.04) - (+0.15)) and HMW-adiponectin lower (P < 0.001; confidence interval (-0.45) - (-0.21)) in OB children than in controls. A reduction in body fat increased T- and HMW-adiponectin and sOB-R (all P < 0.001) and decreased leptin (P < 0.001) and interleukin-6 levels (P < 0.05). After 6 months of sustained weight reduction a decrease in tumoral necrosis factor-α (P < 0.01) occurred, whereas weight recovery increased leptin (P < 0.001) and decreased T-adiponectin (P < 0.05). HMW-adiponectin levels negatively correlated with homeostasis model assessment (HOMA) index and BMI in the whole cohort (both P < 0.001), as did T-adiponectin levels and HOMA index in OB patients (P < 0.01), but neither T- nor HMW-adiponectin correlated with body fat content (BFC) in OB children. We conclude that the impairment of T- and HMW-adiponectin levels in childhood obesity is different to that in elder OB patients, showing closer relationship with carbohydrate metabolism parameters than with BFC, but increasing their levels after weight loss and in association with metabolic improvement.

Background and Aims: Type 2 diabetes mellitus (DM) has a high prevalence in aging obese postmenopausal women. It is not clear whether or not diabetes produces an increase in bone mineral density or an increase in fracture rates., Objective: The main objective of this study was to investigate whether type 2 DM produces a higher prevalence of vertebral, hip and non-vertebral fractures in obese postmenopausal Caucasian women. A secondary objective was to study the influence of DM in quantitative ultrasound measurements of the heel (QUS) and bone mineral density (BMD) measured by dual X-ray absorptiometry (DXA), in both lumbar spine (L2-L4) and proximal femur., Method: This study was a prospective cohort of 111 patients with type 2 DM and 91 control individuals (CTR) over age 65 and obese, recruited from 16 centers in Spain., Main Outcome Measures: Lateral dorsal and lumbar X-rays were performed to assess vertebral fractures. Hip and non-vertebral fractures were noted from medical records, written reports or Xray studies. QUS measurements were made of the calcaneus and BMD measurements of the lumbar spine (L2-L4) and proximal femur., Results: Patients had higher BMD in the lumbar spine (L2-L4) than controls (0.979 g/cm2 vs 0.927 g/cm2, p=0.035), but we found no statistically significant differences in the proximal femur. QUS measurements showed similar values in both groups: BUA (69.3 dB/Mhz vs 66.7 dB/Mhz, p=0.291), SOS (1537 m/sg vs 1532 m/sg, p=0.249) and QUI (87.5 vs 83.7, p=0.153). No statistically significant differences were found in any case. There was no association between vertebral, hip and non-vertebral fractures and DM. The crude odds ratio, without adjusting was 1.045 (CI 95% 0.531 ; 2.059), and the adjusted odds ratio was 0.927 (CI 95% 0.461 ; 1.863)., Conclusions: In obese postmenopausal Caucasian women, type 2 DM produces an increase in BMD of the lumbar spine without changes in BMD of the proximal femur or in QUS measurements of the heel. The prevalence of vertebral, hip and non-vertebral fractures did not increase in type 2 DM.

The mutated gene responsible for the tubby obesity phenotype has been identified by positional cloning. A single base change within a splice donor site results in the incorrect retention of a single intron in the mature tub mRNA transcript. The consequence of this mutation is the substitution of the carboxy-terminal 44 amino acids with 24 intron-encoded amino acids. The normal transcript appears to be abundantly expressed in the hypothalamus, a region of the brain involved in body weight regulation. Variation in the relative abundance of alternative splice products is observed between inbred mouse strains and appears to correlate with an intron length polymorphism. This allele of tub is a candidate for a previously reported diet-induced obesity quantitative trait locus on mouse chromosome 7.

Dual-energy X ray absorptiometry (DEXA) is primarily used in the assessment of bone mineral. However, the transmissions of the two different energy beams in nonbone areas can be processed to calculate the amount of fat and free-fat mass of the soft tissues. We have compared the estimation of body fat mass (FM) by DEXA with data derived from anthropometric (A) (During & Womersley formula) and impedance (BIA) measurements. We have studied 10 subjects, 8 female and 2 male, age 39 +/- 17, weight 97.4 +/- 17.2 kg. The results were: FM 44.4 +/- 8.5 kg (DEXA), 40.6 +/- 6.3 kg (A) and 38.4 +/- 9.8 kg (BIA); FFM 52.1 +/- 14.1 kg (DEXA), 56.8 +/- 13.9 kg (A) and 58.8 +/- 13.6 kg (BIA). The correlation was higher between DEXA and A (r = 0.88, for women r = 0.94). BIA results change depending on the equation used to derive Lean Body Mass (LBM) according to different authors. DEXA measurements are independent from the explorer, whereas A and BIA determinations can change in separate occasions with the same or different observer. Therefore, DEXA method seems more reliable than BIA for the assessment of FM. If DEXA technology is not available, our results support the use of anthropometric over impedance measurements.