1,721,032 research outputs found
Il sistema endocannabinoide e il controllo del metabolismo energetico: fisiologia e fisiopatologia
No full textThe ability of the endocannabinoid system to control appetite, food intake and energy balance has recently received great attention, particularly in the light of the different modes of action underlying these functions. The endocannabinoid system modulates rewarding properties of food by acting at specific mesolimbic areas in the brain. In the hypothalamus, CB1 receptor and endocannabinoids are integrated components of the networks controlling appetite and food intake. Interestingly, the endocannabinoid system has recently been shown to control several metabolic functions by acting on peripheral tissues, such as adipocytes, hepatocytes, the skeletal muscles and the endocrine pancreas. The relevance of the system is further strengthened by the notion that visceral obesity seems to be a condition in which an overactivation of the endocannabinoid system occurs, therefore drugs interfering with this overactivation by blocking CB1 receptor are considered as valuable candidates for the treatment of obesity and related cardiometabolic risk factors. © 2008 AIM Publishing Srl
La terapia farmacologica dell'obesità
No full textObesity is reaching epidemic proportions worldwide and it is correlated with various comorbidities, among which the most relevant are diabetes mellitus, arterial hypertension, and cardiovascular diseases. Obesity management is a modern challenge because of the rapid evolution of unfavorable lifestyles and unfortunately there are no effective treatments applicable to the large majority of obese/overweight people. The current medical attitude is to treat the complications of obesity (e.g. dyslipidemia, hypertension, diabetes, and cardiovascular diseases). However, the potential of treating obesity is enormous, bearing in mind that a volitional weight loss of 10 kg is associated with important risk factor improvement: blood pressure -10 mmHg, total cholesterol -10%, LDL cholesterol -15%, triglycerides -30%, fasting glucose -50%, HDL cholesterol +8%. Drug treatment for obesity is an evolving branch of pharmacology, burdened by severe side effects and consequences of the early drugs, withdrawn from the market, and challenged by the lack of long-term data on the effect of medications on obesity-related morbidity and mortality, first of all cardiovascular diseases. In Europe three antiobesity drugs are currently licensed: sibutramine, orlistat, and rimonabant; important trials with clinical endpoints are ongoing for sibutramine and rimonabant. While waiting for their results, it is convenient to evaluate these drugs for their effects on body weight and cardiometabolic risk factors. Sibutramine is a centrally acting serotonin/noradrenaline reuptake inhibitor that mainly increases satiety. At the level of brown adipose tissue, sibutramine can also facilitate energy expenditure by increasing thermogenesis. The long-term studies (five) documented a mean differential weight reduction of 4.45 kg for sibutramine vs placebo. Considering the principal studies, attrition rate was 43%. This drug not only reduces body weight and waist circumference, but it decreases triglycerides and uric acid as well and it increases HDL cholesterol; in diabetics it improves glycated hemoglobin. Sibutramine has conflicting effects on blood pressure: in some studies there was a minimal decrease, in some others a modest increase. In all the studies this drug increased pulse rate. Sibutramine is not recommended in patients with uncontrolled hypertension, or in case of history of cardio- and cerebrovascular disease. Orlistat is a pancreatic lipase inhibitor that reduces fat absorption by partially blocking the hydrolysis of dietary triglycerides. A recent meta-analysis evaluated 22 studies lasting for at least 12 months, in obese patients with a mean body mass index of 36.7 kg/m2, where orlistat was associated with hypocaloric diet or behavioral interventions: the net average weight loss was 2.89 kg (confidence interval 2.27-3.51 kg). Considering the principal studies, attrition rate ranged from 33 to 57%. Orlistat significantly decreases waist circumference, blood pressure, total and LDL cholesterol, but has no effect on HDL and triglycerides. This drug significantly reduced the incidence of diabetes only in subjects with impaired glucose tolerance. The major adverse effects with orlistat are mainly gastrointestinal (fatty and oily stool, fecal urgency, oily spotting, fecal incontinence) and attenuate over time. Orlistat should be avoided in patients with chronic malabsorption and cholestasis. Rimonabant is a selective antagonist of cannabinoid type 1 receptor. This drug, by inhibiting the overactivation of the endocannabinoid system, produces anorectic stimuli at the central nervous level, but also has effects on the peripheral systems involved in metabolism control, such as liver, adipose tissue, skeletal muscles, endocrine pancreas, and gastrointestinal apparatus, influencing many processes partially unknown. An ample experimental program named RIO (Rimonabant In Obesity) involved about 6600 obese or overweight patients to identify the effects of rimonabant in weight loss and associated cardiometabolic abnormalities, over and beyond a caloric restriction of 600 kcal in the treatment and placebo arms. In the four double-blind RIO trials published (Rio-North America, RIO-Europe, RIO-Lipids, RIO-Diabetes), rimonabant 20 mg significantly (p < 0.001) reduced weight by 6.3-6.9 kg in the non-diabetic groups vs placebo (-1.5-1.8 kg), whereas in the diabetic subjects enrolled in RIO-Diabetes, weight loss was 5.3 vs 1.4 kg in the placebo group. Attrition rate at 1 year ranged between 40 and 50%, similar to the studies with sibutramine or orlistat. Similarly to weight loss, also waist circumference was significantly reduced by rimonabant. As for cardiometabolic parameters, rimonabant induced a significant increase in HDL cholesterol and a significant decrease in triglycerides. Even if no significant LDL reduction was achieved, the RIO-Lipids study showed a significant decrease in small dense LDL particles, more atherogenic, in rimonabant-treated subjects. Non-diabetic treated patients improved basal insulin and indirect indexes of insulin resistance, while in the RIO-Diabetes study, the only one including diabetics, glycated hemoglobin improved by 0.7% in the active treatment arm vs placebo. The effects on HDL cholesterol and glycated hemoglobin seem in a large percentage unrelated to weight loss. These effects have been confirmed by another trial, named SERENADE, evaluating the treatment in naive diabetic patients. Rimonabant is not recommended in patients with a history of depressive disorders or suicidal ideation and with uncontrolled psychiatric illness, and is contraindicated in patients with ongoing major depression or ongoing antidepressive treatment. In conclusion, despite an enormous advancement in basic research to understand the pathogenetic mechanisms at the base of obesity, the pharmacological research did not reach the therapeutic opportunities available for other chronic conditions, like hypertension and dyslipidemia. However, the few molecules available for clinical practice (sibutramine, orlistat, rimonabant) have shown, when properly used, to contribute to reduce body weight and undoubtedly improve cardiometabolic risk factors. With this preamble, according to current guidelines and pharmacoeconomic studies, patients who might benefit from antiobesity treatment are those with a body mass index ≥ 30 or 27-29.9 kg/m2 with major obesity-related comorbidities such as hypertension, diabetes, dyslipidemia, obstructive sleep apnea, and metabolic syndrome. © 2008 AIM Publishing Srl
Obesity-related proliferative diseases: The interaction between adipose tissue and estrogens in post-menopausal women
No full textEpidemiological studies have shown that overweight and cancer are closely related, even though obesity alone does not apparently heighten cancer risk by the same amount. Given the low overall risk of all cancers with obesity, it is unlikely that obesity alone causes cancer, but should instead be considered as a tumor promoter. There are three main hypotheses that could explain how obesity might contribute to cancer development and growth: the inflammatory cytokines from adipose tissue hypothesis, the insulin resistance and hyperinsulinemia hypothesis, and the unopposed estrogen cancer hypothesis. The link between obesity and cancer is that adipocytes constitute a major component of the tumor microenvironment for breast and abdominally metastasizing cancers, promoting tumor growth. This review will mainly focus attention on the relationship between adipose tissue, estrogens, and cancer risk
Aldosterone and type 2 diabetes mellitus
No full textPrimary hyperaldosteronism (PA) has recently been demonstrated to be strictly associated to metabolic syndrome as compared with essential hypertension (EH). Besides, the characteristics of metabolic syndrome are different in PA compared to EH, as high fasting glucose is more frequent in the former condition. The adverse effect of excess aldosterone on insulin metabolic signaling has generated increasing interest in the role of hyperaldosteronism in the pathogenesis of insulin resistance and resistant hypertension. Moreover, aldosterone receptor antagonist therapy in diabetic and cardiopathic patients improved coronary flow. The aim of this review is to present recent knowledge about the relationship between aldosterone, insulin resistance and diabetes
Cross-talk between adipose tissue and the HPA axis in obesity and overt hypercortisolemic states
No full textIn addition to its roles in providing insulation and mechanical support, adipose tissue (AT) has been recognised as the major site for storage of surplus fuel. Since leptin was discovered, white AT (WAT) has been recognised as an endocrine organ and an important source of biologically active substances with local and/or systemic action called adipokines. The metabolic and endocrine activities of AT are under the control of several hormones: a particular role has been played by glucocorticoids (GC), which able to participate, along with other hormones, both in recruitment of progenitor cells and in differentiation and secretive activities. AT is also able to generate cortisol from cortisone through 11β-hydroxysteroid-dehydrogenase (11β-HSD). There are controversial reports in the literature, showing a hyperactivity of 11β-HSD in obesity. It has been postulated that obesity, particularly the visceral body fat distribution (V-BFD), may be considered a maladaptation to stress exposure, thus leading to hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis, and higher-than-normal cortisol levels. In this review, we will examine the cross-talk between the HPA axis and AT, their relationship under stressful events, depending on steroid hormones and different adipokine secretions
Secondary hyperaldosteronism and liver fibrosis in patients with compensated chronic liver disease or portal hypertension
No full textNon present
Phosphate Metabolism and Pathophysiology in Parathyroid Disorders and Endocrine Tumors
Full text linkThe advent of new insights into phosphate metabolism must urge the endocrinologist to
rethink the pathophysiology of widespread disorders, such as primary hyperparathyroidism, and
also of rarer endocrine metabolic bone diseases, such as hypoparathyroidism and tumor-induced
hypophosphatemia. These rare diseases of mineral metabolism have been and will be a precious
source of new information about phosphate and other minerals in the coming years. The parathyroid
glands, the kidneys, and the intestine are the main organs affecting phosphate levels in the blood
and urine. Parathyroid disorders, renal tubule defects, or phosphatonin-producing tumors might be
unveiled from alterations of such a simple and inexpensive mineral as serum phosphate. This review
will present all these disorders from a ‘phosphate perspective’
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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