Irisin is a myokine involved in the browning of white adipose tissue and regulation of energy expenditure, glucose homeostasis and insulin sensitivity. Debated evidence exists on the metabolic role ...played by irisin in children with overweight or obesity, while few information exist in children with Prader Willi Syndrome (PWS), a condition genetically prone to obesity. Here we assessed serum irisin in relation to the metabolic profile and body composition in children and adolescents with and without PWS. In 25 PWS subjects age 6.6-17.8y; body mass index standard deviation score (BMI SDS) 2.5 ± 0.3 and 25 age, and BMI-matched controls (age 6.8-18.0y; BMI SDS, 2.8 ± 0.1) we assessed irisin levels and metabolic profile inclusive of oral glucose tolerance test (OGTT), and body composition by dual-energy X-ray absorptiometry (DXA). In PWS, we recorded lower levels of fat-free mass (FFM) (p <0.05), fasting (p<0.0001) and 2h post-OGTT insulin (p<0.05) and lower insulin resistance as expressed by homeostatic model of insulin resistance (HOMA-IR) (p<0.0001). Irisin levels were significantly lower in PWS group than in controls with common obesity (p<0.05). In univariate correlation analysis, positive associations linked irisin to insulin OGTT
0
(p<0.05), insulin OGTT
120
(p<0.005), HOMA-IR (p<0.05) and fasting C-peptide (p<0.05). In stepwise multivariable regression analysis, irisin levels were independently predicted by insulin OGTT
120
. These results suggest a link between irisin levels and insulin sensitivity in two divergent models of obesity.
Context: The diagnosis of Cushing’s syndrome requires highly sensitive screening tests. Therefore, diagnostic cutoffs have been lowered to maximize sensitivity and identify all patients. However, few ...studies have investigated the impact of these refinements on the specificity of first-line tests.
Objective: The aim of the study was the assessment of the specificity of three widely used screening tests in a large series of Cushing’s syndrome suspects referred to our endocrine service.
Patients: We retrospectively reviewed the results of urinary free cortisol (UFC), 1-mg dexamethasone suppression test overnight suppression test (OST), and serum cortisol at midnight in 3461, 357, and 864 patients, respectively, with clinical features suggestive of Cushing’s syndrome but in whom this diagnosis was subsequently excluded.
Results: UFC and OST at the 5-μg/dl cutoff exhibited the highest specificities 91% (95% confidence intervals CI 90.2–92.1%) and 97% (95% CI 96.3–98.5%), respectively. Conversely, midnight serum cortisol yielded 87% (95% CI 84.3–91.1%) specificity only with the 7.5-μg/dl cutoff, whereas the 1.8-μg/dl threshold resulted in an unacceptably high proportion of false positives at only 20% specificity (95% CI 16.0–24.4%). Gender and age may lead to misleading results in all three screening tests.
Conclusions: Specificity of tests for Cushing’s syndrome varies considerably, with OST and UFC presenting the best performances, and circadian rhythm appearing heavily impaired by lowering of diagnostic cutoffs. Indeed, the vast majority of individuals in our series presented midnight serum cortisol values greater than 1.8 μg/dl; thus, caution has to be exercised when this criterion is used to exclude Cushing’s syndrome.
Objective: To investigate the relationship between oxytocin, menopause and obesity. Methods: A cross-sectional analysis on 56 obese (OB; 28 premenopausal) and 53 normal-weight women (NW; 27 ...premenopausal) was performed by measurement of oxytocin, leptin, adiponectin, gonadotropins, sex steroids, glucose, and lipid homeostasis as well as DXA assessment of fat mass (%FM) and fat-free mass (FFM). Results: Women from NW and OB groups were comparable for age but differed in anthropometric measures. In our cohorts, menopause was not associated with changes in gluco-lipid homeostasis and %FM, while FFM was lower in postmenopausal women from both study groups (p < 0.05). In each group, leptin was unaltered, and adiponectin only marginally changed across menopause, while oxytocin levels were lower in post- than in premenopausal women (NW: p < 0.05; OB: p < 0.005), and lower in OB than NW women, either when assessed as whole groups or if stratified by menopause (p < 0.001). In correlation analysis, inverse associations related oxytocin to menopause, obesity, and adiposity-related measures. BMI (p < 0.0001) and menopause independently predicted oxytocin levels (p < 0.001), but their interaction was null (p = 0.5). Conclusions: Obesity and menopause are independent negative predictors of plasma oxytocin. Longitudinal studies should clarify the role of oxytocin on weight modifications experienced around and after menopause.
The last decades have provided insights into vitamin D physiology linked to glucose homeostasis. Uncertainties remain in obesity due to its intrinsic effects on vitamin D and glucose tolerance.
To ...assess the relationship between vitamin D and glucose abnormalities in severely obese individuals previously unknown to suffer from abnormal glucose metabolism.
Tertiary care centre.
524 obese patients (50.3 ± 14.9 yrs; BMI, 47.7 ± 7.3 kg/m2) screened by OGTT, HbA1c and the lipid profile. Vitamin D status was assessed by 25(OH)D3, PTH and electrolyte levels. 25(OH)D3 deficiency/insufficiency were set at 20 and 30 ng/ml, respectively. All comparative and regression analyses were controlled for age, BMI and gender.
The prevalence of vitamin D deficiency/insufficiency and secondary hyperparathyroidism were 95% and 50.8%, respectively. Normal glucose tolerance (NGT), impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), and type 2 diabetes mellitus (T2DM) were found in 37.8%, 40.5% and 21.7% of cases, respectively. Large variations in metabolic parameters were seen across categories of vitamin D status, but the only significant differences were found for C-peptide, tryglicerides, LDL- and HDL-cholesterol levels (p < 0.05 for all). The prevalence of vitamin D deficiency was documented to be slightly but significantly more frequent in glucose-intolerant patients (IFG + IGT + T2DM) compared to the -normotolerant counterpart (87% vs. 80%, p < 0.05). In partial correlation analyses, there was no association between vitamin D levels and glucose-related markers but for HbA1c (r = -0.091, p < 0.05), and both basal and OGTT-stimulated insulin levels (r = 0.097 and r = 0.099; p < 0.05 for all). Vitamin D levels were also correlated to HDL-cholesterol (r = 0.13, p = 0.002). Multivariate regression analysis inclusive of vitamin D, age, BMI, gender and fat mass as independent variables, showed that vitamin D was capable of predicting HbA1c levels (β = -0.101, p < 0.05).
Given the inherent effect of obesity on vitamin D and glucose homeostasis, current data suggest a potential independent role for vitamin D in the regulation of glucose metabolism in a setting of obese patients previously unknown to harbour glucose metabolism abnormalities.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The effective illusory ownership over an artificial body in modulating body representations in healthy and eating disorders population has been repeatedly reported in recent literature. In this ...study, we extended this research in the field of obesity: specifically, we investigated whether ownership over a virtual body with a skinny abdomen might be successfully experienced by participants affected by obesity.
Fifteen participants with obesity and fifteen healthy-weight participants took part at this study in which the VR-Full-Body Illusion was adopted. The strength of illusion was investigated through the traditional Embodiment Questionnaire, while changes in bodily experience were measured through a body size estimation task.
Participants with obesity as well as healthy-weight participants reported to experience the illusion. About the body size estimation task, both groups reported changes only in the estimation of the abdomen's circumference after the experimental condition, in absence of any another difference.
Participants with obesity reported to experience the illusion over a skinny avatar, but the modulation of the bodily experience seems controversial. Future lines of research exploiting this technique for modulating body representations in obesity, specifically in terms of potential therapeutic use, were discussed.
Different approaches, involving different areas and figures, are useful for the rehabilitation of obese subjects through a multidisciplinary hospital path. A focal point of rehabilitation is ...represented by education on healthy eating by increasing the dietary knowledge patients. Few tools investigating food knowledge are available in Italy: therefore, the need has emerged to develop easy-to-use tools for clinical practice that allow to detect food knowledge to set up a more targeted food re-education. The following work aimed at building and validating a questionnaire capable of investigating the dietary knowledge of the population affected by obesity.
A pool of experts carried out a review of the literature, gathering all the information necessary to select and construct the best set of questions and the format of the final project of the questionnaire. During statistical analysis the validity, reproducibility and stability of the questionnaire were investigate in a sample of 450 subjects with obesity.
Early analysis disclosed that 5 questions of the original questionnaire had no discriminating power. The successive validation phases were successful, confirming good content validity, stability and reproducibility over time.
The questionnaire has all the characteristics to be considered a valid tool for investigating dietary knowledge in the obese population. The psychometric tests confirmed a good internal consistency of the structure, a validity of the content, a good reproducibility and stability over time.
Sommario
L’interessamento osteoarticolare costituisce un elemento rilevante della patologia acromegalica, spesso presente già alla diagnosi sotto forma di artralgie; tale complicanza, pur non ...determinando riduzione dell’aspettativa di vita, causa importante disabilità influenzando in modo negativo la qualità di vita dei pazienti. La patogenesi, ancora non del tutto chiarita, sembrerebbe riconducibile in prima istanza all’eccesso di GH e IGF-I e, in una seconda fase, alle conseguenti modificazioni meccaniche di tipo degenerativo. L’entità delle manifestazioni cliniche, così determinante sulla qualità di vita dei soggetti affetti, non trova fedele riscontro nella gravità del quadro radiologico. La Società Italiana di Endocrinologia ha varato un Gruppo di Studio sulla Disabilità Motoria nell’Acromegalia, a cui partecipano numerosi gruppi endocrinologici italiani.
Summary
Objective Cushing's syndrome (CS), when fully expressed, is easily diagnosed. Mild cases, however, may require careful distinction from pseudo‐Cushing's states as may occur in depression, ...alcoholism, polycystic ovary disease and visceral obesity. The aim of the present study is a reappraisal of the diagnostic accuracy of the two tests most commonly used to differentiate CS from pseudo‐Cushing's: corticotropin‐releasing hormone (CRH) stimulation after low dose dexamethasone administration and desmopressin stimulation.
Design The study population comprised 32 patients with CS and 23 with pseudo‐Cushing's evaluated retrospectively.
Methods Urinary free cortisol (UFC), serum cortisol at midnight and after low dose dexamethasone (1 mg overnight and 2 mg over two days) were measured. Further, patients were tested with dexamethasone + CRH and desmopressin and the diagnostic performances of the two tests were compared in the entire series as well as in patients with mild hypercortisolism only (i.e. UFC < 690 nmol/24 h).
Results As expected, measurement of UFC, assessment of cortisol rhythmicity and inhibition after 1 mg/2 mg dexamethasone failed to clearly classify patients with pseudo‐Cushing's. Administration of CRH following 2‐mg dexamethasone achieved 100% sensitivity but 62·5% specificity. Conversely, desmopressin testing correctly classified all but two patients with pseudo‐Cushing's (90% specificity) with 81·5% sensitivity. Diagnostic accuracy was comparable in the subgroup with mild hypercortisolism (21 CS, all 23 pseudo‐Cushing's patients). Desmopressin offered an incremental diagnostic effectiveness of 35·8/million inhabitants compared with dexamethasone + CRH as a second‐line test.
Conclusions Neither of the two tests guarantees absolute diagnostic accuracy. The specificity of dexamethasone + CRH is less brilliant than previously reported and appears to be inferior to desmopressin stimulation. The greatest diagnostic effectiveness results from the low‐dose dexamethasone test combined with the desmopressin test. Skilful use of dynamic testing and balanced clinical judgement are necessary to distinguish between Cushing's syndrome and pseudo‐Cushing's.
Neuroendocrine control of food intake Valassi, Elena; Scacchi, Massimo; Cavagnini, Francesco
Nutrition, metabolism, and cardiovascular diseases,
02/2008, Letnik:
18, Številka:
2
Journal Article
Recenzirano
Abstract Appetite is regulated by a complex system of central and peripheral signals which interact in order to modulate the individual response to nutrient ingestion. Peripheral regulation includes ...satiety signals and adiposity signals, while central control is accomplished by several effectors, including the neuropeptidergic, monoaminergic and endocannabinoid systems. Satiety signals, including cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), originate from the gastrointestinal (GI) tract during a meal and, through the vagus nerve, reach the nucleus tractus solitarius (NTS) in the caudal brainstem. From NTS afferents fibers project to the arcuate nucleus (ARC), where satiety signals are integrated with adiposity signals, namely leptin and insulin, and with several hypothalamic and supra-hypothalamic inputs, thus creating a complex network of neural circuits which finally elaborate the individual response to a meal. As for the neuropeptidergic system, ARC neurons secrete orexigenic substances, such as neuropeptide Y (NPY) and agouti-related peptide (AGRP), and anorexigenic peptides such as pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART).Other brain areas involved in the control of food intake are located downstream the ARC: among these, the paraventricular nucleus (PVN), which produces anorexigenic peptides such as thyrotropin releasing hormone (TRH), corticotrophin releasing hormone (CRH) and oxytocin, the lateral hypothalamus (LHA) and perifornical area (PFA), secreting the orexigenic substances orexin-A (OXA) and melanin concentrating hormone (MCH). A great interest in endocannabinoids, important players in the regulation of food intake, has recently developed. In conclusion, the present work reviews the most recent insights into the complex and redundant molecular mechanisms regulating food intake, focusing on the most encouraging perspectives for the treatment of obesity.
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