|
PWS Articles PWS Research
Other |
[ Printable Page | Edit ]
Research Notes: AdiponectinJ Clin Endocrinol Metab. 2007 Jan 30. Context: Children with Prader-Willi Syndrome (PWS) may have obesity and an abnormal body composition with a high body fat percentage, even if they have a normal body weight. Adiponectin has been inversely related to obesity and insulin resistance. Objective: To evaluate in pre-pubertal PWS children (1) adiponectin levels, body composition, carbohydrate metabolism, and triglyceride levels, (2) associations between adiponectin and body composition, carbohydrate metabolism and triglycerides, and (3) effects of growth hormone (GH)-treatment on these outcome measures. Patients: 20 pre-pubertal PWS children. Intervention: The subjects were randomized into a GH-treatment group (n=10, 1mg/m(2)/day) and a non-GH treated control-group (n=10). Main Outcome Measures: At baseline, after 1 and 2 years of GH-treatment, fasting levels of adiponectin, glucose, insulin, and triglycerides were assessed. Body composition and fat distribution were measured by Dual Energy X-ray Absorptiometry. Results: PWS children had significantly higher median (interquartile range) adiponectin levels (17.1mg/l(13.9-23.2)) than healthy sex- and age-matched controls (11.8mg/l(9.7-12.5), p<0.005). Body fat percentage was significantly higher than 0 SDS (1.8 SDS(1.5-2.1), p<0.001). Adiponectin levels were inversely related to triglyceride levels (r=-0.52, p=0.03). There was a tendency to an inverse relation with body fat percentage and BMI, but no correlation with fasting insulin or glucose levels, the insulin/glucose ratio or HOMA-index. During GH-treatment, adiponectin levels increased significantly and did not change in randomized controls. Conclusion: Adiponectin levels were increased, and inversely associated with triglyceride levels, in pre-pubertal, not overweight PWS children, although they had a relatively high body fat percentage. During GH-treatment, adiponectin levels further increased, whereas no change was found in the controls, which is reassuring with respect to the development of insulin resistance during GH-treatment. Regul Pept. 2006 Nov 14. Adiponectin, an adipocyte-derived polypeptide hormone, plays an important role in regulating fatty acid oxidation. beta-oxidation of fatty acids supplies most of the cardiac energy and carnitine palmitoyltransferase (CPT)-1 serves as a key regulator during this process. To characterize the potential effects of adiponectin on CPT-1, we incubated rat neonatal cardiomyocytes with globular adiponectin (gAd). Results showed that gAd promoted the activity and mRNA expression of CPT-1. The underlying signal pathway involved in this modulatory effect was further investigated. Inhibition of AMP-activated protein kinase (AMPK) with adenine 9-beta-d-arabinofuranoside (AraA) completely abrogated gAd-mediated AMPK and acetyl coenzyme A carboxylase (ACC) phosphorylation and suppressed the promotion of CPT-1 activity. gAd also induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and peroxisome proliferator-activated receptor (PPAR)-alpha, which was inhibited by AraA. SB202190, a p38MAPK inhibitor, blocked gAd-stimulated PPAR-alpha phosphorylation. When AMPK and/or p38MAPK was inhibited, gAd-enhanced mRNA expression of CPT-1 was partially reduced. In conclusion, our study suggests that the activation of AMPK signaling cascade participates in the promotion effect of gAd on CPT-1. Horm Res. 2006 Nov 2. Prader-Willi syndrome (PWS) is a genetic disorder characterized by dysmorphic features, obesity, hypogonadism, hypotonia and mental retardation. Obesity has been linked to insulin resistance and the latter has also been associated with premature adrenarche. Since up to date a controlled study to investigate adrenarche and its hormonal regulation was lacking in PWS, our aim was to assess whether prepubertal PWS patients develop premature adrenarche and its relationship with markers of insulin sensitivity. Fourteen prepubertal children with PWS (6 M, 8 F) and 10 non-syndromal simple obese matched controls (5 M, 5 F) participated (mean age: 7.62 +/- 1.84 years). A fasting blood sample was obtained for adrenal and ovarian androgens, sex hormone binding globulin, insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-1, leptin, adiponectin and a lipid profile. Thereafter an oral glucose tolerance test was performed. PWS patients were smaller at birth and a higher proportion displayed premature pubarche. No differences were found in testosterone, androstenedione, sex hormone binding globulin, free androgen index, homeostatic model assessment-IR, 2-hour insulin, leptin or adiponectin levels. 17-hydroxyprogesterone and DHEAS levels however, were significantly higher in PWS. IGF-I levels were significantly lower in PWS and correlated significantly with height SDS (p < 0.05). In conclusion, a higher proportion of premature adrenarche in our PW patients was observed, which was not explained by differences in insulin sensitivity or plasma levels of adipokines and IGF-I. Int J Obes (Lond). 2006 Feb. BACKGROUND: People with obesity and/or the metabolic syndrome have an increased risk for developing diabetes and cardiovascular disease and may have low adiponectin levels. The obesity associated with Prader-Willi syndrome (PWS) would be expected to have similar complications. However, it was recently reported that, despite their adiposity, people with PWS have reduced visceral fat and are less likely to develop diabetes mellitus or the metabolic syndrome compared with people with simple obesity. OBJECTIVE: To determine if plasma adiponectin levels and other variables relevant to diabetes and cardiovascular risk are different in a cohort of PWS subjects with known genetic subtypes compared with age-, sex- and weight-matched control subjects. RESULTS: Fasting plasma glucose, C-peptide, triglycerides, leptin and cholesterol levels were similar in PWS and obese subjects. Our 20 PWS subjects (mean age = 27.7 years) had higher percent body fat (54.1 vs 48.5%) determined by DEXA measurements and lower percent lean mass (45.9 vs 51.5%) compared with 14 obese controls (mean age = 26.9 year). Plasma adiponectin levels were significantly higher in PWS (15.5 +/- 8.2 microg/ml) than in obese controls (7.5 +/- 2.7 microg/ml). A significant positive correlation was found with insulin sensitivity in PWS subjects (r = 0.75, P = 0.0003) but not in obese controls (r = 0.36, P = 0.20). DISCUSSION: Our study confirmed an earlier observation of higher adiponectin levels in PWS subjects and less insulin resistance proportionate to their obesity status than found in subjects with simple obesity. Furthermore, no differences were seen in PWS subjects with the chromosome 15 deletion or maternal disomy 15. The reported excessive visceral adiposity in subjects with simple obesity compared with PWS may be associated with decreased production and lower circulating levels of adiponectin. Horm Res. 2006. AIM: To investigate fasting and postprandial adiponectin levels in PWS patients as compared to obese and lean subjects and whether they could contribute to the pathogenesis of obesity in this syndrome. METHODS: We studied 7 patients with PWS, 16 obese patients and 42 lean subjects for the fasting study. From this group, we evaluated 7 patients with PWS, 7 age-sex-BMI-matched obese non-PWS patients and 7 age-sex-matched lean subjects before and after the administration of 3,139.5 kJ (750 kcal) of a standard liquid meal (53.2% carbohydrate, 30% fat, 16.7% protein) after an overnight fast. Blood samples were obtained every 15 min for the first hour and every 30 min thereafter until 6 h. Adiponectin, IGF-I, glucose, triglycerides, cholesterol, and insulin were measured. RESULTS: Fasting plasma adiponectin levels were lower in PWS than in lean subjects (5.24+/-2.56 vs. 8.28+/-4.63 microg/ml, p=0.041) but higher than in obese patients (4.01+/-1.27 microg/ml, p=0.047). After the meal, adiponectin concentrations mildly decreased in PWS at time point 240 min, while in obese and lean subjects no changes were observed. However, 6-hour postprandial AUC for adiponectin was similar in all three groups. CONCLUSION: Fasting adiponectin levels are low in PWS, but they are so mildly modulated postprandially that these changes do not seem significant for the pathogenesis of obesity in this syndrome. Horm Res. 2006. BACKGROUND: In Prader-Willi syndrome (PWS) obesity and partial growth hormone (GH) deficiency are frequently observed. The risks of cardiovascular diseases and early death are increased. We examined inflammatory markers in adult PWS, before and during 12 months of GH treatment. METHOD: Twelve PWS adults, median age 23.5 years (17-37) and median BMI 33.8 kg/m2 (21.2-50.4), participated. Serum interleukin-6, tumour necrosis factor alpha, high sensitive protein C-reactive protein (HCRP), cholesterol, triglycerides, leptin, adiponectin, glucose, insulin, insulin-like growth factor I and body composition were measured at baseline and after 6 and 12 months of GH treatment. RESULTS: Median and range at baseline for interleukin-6 was 9.87 ng/l (1.76-10.72), for tumour necrosis factor alpha 2.39 ng/l (1.00-3.26) and for HCRP 7.64 mg/l (0.41-41.1) (normal values < 5 ng/l, < 8 ng/l and<5 mg/l, respectively). At baseline correlations between inflammatory markers and age, anthropometry, body composition and the metabolic parameters were non-significant; only positive associations were found between tumour necrosis factor alpha and body weight (r = 0.617, p = 0.033) and between HCRP and BMI (r = 0.594, p = 0.041). GH treatment non-significantly decreased the levels of the inflammatory markers. CONCLUSION: In this pilot study, levels of interleukin-6 and HCRP were increased, and GH intervention did not significantly reduce the levels. Chronic inflammation might contribute to the increased cardiovascular morbidity and mortality in PWS. J Clin Endocrinol Metab. 2005 Jul. CONTEXT: Determinants of insulin resistance in Prader-Willi syndrome (PWS) are not completely understood. The discovery of several adipokines with relevant effects on insulin resistance and cardiovascular complications of metabolic syndrome offered new tools of investigation of insulin resistance in PWS. OBJECTIVE: The purpose of this study was to measure serum resistin and mRNA in adipose tissue of patients with PWS, those with simple obesity, and healthy controls and correlate resistin levels with anthropometric and biochemical features. DESIGN: Twenty-eight adult PWS patients, 29 obese patients, and 25 healthy controls were studied. Anthropometric variables were measured and fasting serum and plasma were collected for measurement of resistin, adiponectin, leptin, lipid profile, glucose, and insulin. RESULTS: Serum resistin and resistin mRNA expression in adipose tissue was significantly higher in PWS patients, compared with both healthy lean controls and obese patients. Moreover, on regression analysis resistin was significantly correlated with body mass index, whereas no significant association was found between resistin and homeostasis model assessment index. A weak association between resistin and adiponectin was found in the PWS group only. However, on multivariate analysis only the correlation between resistin and body mass index remained significant. CONCLUSIONS: These results support a link between circulating resistin and obesity in humans but do not support a role for resistin in human insulin resistance. Eur J Endocrinol. 2004 Oct. OBJECTIVE: Obesity and growth hormone (GH) deficiency are common in Prader-Willi syndrome (PWS) and these patients are at risk of metabolic diseases in adult life and of reduced life span. Low adiponectin values are associated with obesity and the metabolic syndrome. We therefore found it of interest to measure adiponectin levels in PWS. PATIENTS AND METHODS: 17 adults, nine men and eight women, 17 to 32 years of age, with a mean body mass index (BMI) of 35+/-3.2 kg/m2 participated. All had clinical PWS. They were randomized to treatment with placebo or GH (Genotropin) for six months, and subsequently all received GH for 12 months. At baseline, serum total adiponectin levels in the PWS patients were compared with 25 lean and 34 obese controls. Body composition and various metabolic parameters, including adiponectin, were studied every six months in the PWS group. RESULTS: Serum adiponectin levels in PWS subjects were significantly lower (P<0.001) compared with lean and significantly higher (P<0.001) compared with obese controls. In PWS patients, no correlation was found between adiponectin and anthropometrical parameters or measures of insulin sensitivity (e.g. fasting insulin and insulin sensitivity as estimated by the homeostasis model assessment), or between adiponectin and IGF binding protein-1 or IGF-I. Adiponectin did not change during GH intervention. CONCLUSION: In this study of adults with PWS serum total adiponectin levels were higher than in controls with simple obesity and were independent of anthropometrical parameters. In accordance with this the metabolic syndrome is not necessarily present in all PWS patients. Correction of GH deficiency had no effect on serum adiponectin levels. Zhonghua Jie He He Hu Xi Za Zhi. 2004 Aug. Objective: To explore the changes of serum adiponectin levels in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). Methods: Polysomnography was performed in 71 obese OSAHS patients (obese OSAHS group), 21 OSAHS patients without obesity (non-obese OSAHS group), 26 obese controls (obese group) and 22 normal healthy adults (control group). In both the obese OSAHS group and obese group, the body mass index (BMI) was higher than 25 and there was no significant difference in BMI. Serum adiponectin levels were measured by radioimmunoassay. Results: The serum adiponectin level in the control group [(8.9 +/- 0.6) mg/L] was significantly higher than those in the obese group [(7.1 +/- 1.3) mg/L, P < 0.05], the non-obese OSAHS group [(5.4 +/- 0.6) mg/L, P < 0.01] and the obese OSAHS group [(5.0 +/- 1.0) mg/L, P < 0.01] respectively. The serum adiponectin level was significantly lower in both the obese OSAHS group and the non-obese OSAHS group (all P < 0.05). The serum adiponectin levels between the obese OSAHS group and the non-obese OSAHS group showed no statistical difference (P > 0.05). In the obese OSAHS patients and the obese patients serum adiponectin levels were negatively correlated with AHI (r = -0.78, P < 0.01), BMI (r = -0.21, P < 0.05), waist circumference (r = -0.36, P < 0.01), and neck circumference (r = -0.42, P < 0.01), but positively correlated with minimal pulse oxygen saturation (r = 0.48, P < 0.01). Conclusions: Serum adiponectin levels were significantly lower in OSAHS patients than in the normal control and the obese patients. In addition to increased waist and neck circumferences, OSAHS may contribute to the decreased serum adiponectin level. |