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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Body mass--strictly speaking: the adipose tissue mass--is regulated in a feed-back system by the hypothalamus and brainstem, where adiposity signals (leptin, insulin, amylin) and intestinal peptides (ghrelin, PYY, PP, GLP-1, OXM, CCK) and the vagal nerve provide afferent information to the central controller on the size of white adipose tissue and the actual nutritional state, respectively. Two distinct groups of neurons in the arcuate nucleus accept and process the afferent information provided by leptin produced by white adipocytes in proportion to their mass. Leptin binding to the leptin-receptors on the surface of these neurons initiates intracellular signal transduction and activation of target genes, resulting in the synthesis and release of neuropeptides (POMC, CART) with anorectic effects. Secondary centers in the brain are also activated, and finally integrated effector mechanisms are generated in order to regulate the balance between energy intake and expenditure. The regulation of body weight is carried out by the central nervous system in a complex and redundant way, characterized by interconnections and overlaps with other neuroendocrine functions, such as growth, thyroid and adrenal function, memory, addictive and reward mechanisms. Targeting one or another component of this complicated system with drugs might result in interference with other systems and functions, so the occurrence of adverse events is probable. The worldwide epidemic of obesity--resulting mostly from the abundance of energy-dense foods and sedentary lifestyle coupled with a regulatory system unable to cope with this environment--has resulted in a continuous increase of research activities in both academic and industrial centers to develop new drugs and treatment strategies beyond lifestyle changes (diet, physical activity and behavioral therapy) to fight obesity more effectively.
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PMID:[The regulation of body mass and its relation to the development of obesity]. 1789 Jan 70

We recently described a novel mouse model that combines resistance to lactogenic hormones with GH deficiency (GHD). The GHD/lactogen-resistant males develop obesity and insulin resistance with age. We hypothesized that altered production of pancreatic hormones and dysregulation of adipocytokine secretion and action contribute to the pathogenesis of their insulin resistance. Double-mutant males (age 12-16 months) had fasting hyperinsulinemia, hyperamylinemia, hyperleptinemia, and a decreased ratio of adiponectin to leptin. Adiponectin receptor 1 and 2 (AdipoR1 and R2) mRNA levels in liver and skeletal muscle were normal but hepatic insulin receptor mRNA was increased. Relative to double-mutant males, GHD males had lower levels of insulin, amylin, and leptin, higher levels of adiponectin, and higher expression of hepatic AdipoR1 and insulin receptor mRNAs. Lactogen-resistant mice had reduced hepatic adipoR2 mRNA. In response to stress the plasma concentrations of MCP-1 and IL-6 increased in double-mutant males but not GHD or lactogen-resistant males. Our findings suggest that the insulin resistance of GHD/lactogen-resistant males is accompanied by dysregulation of pancreatic hormone and adipocytokine secretion and receptor expression. Phenotypic differences between double-mutant and GHD males suggest that lactogens and GH exert differential but overlapping effects on fat deposition and adipocytokine secretion and action.
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PMID:Effects of lactogen resistance and GH deficiency on mouse metabolism: pancreatic hormones, adipocytokines, and expression of adiponectin and insulin receptors. 1797 45

The majority of patients with type 2 diabetes mellitus are overweight or obese at the time of diagnosis, and obesity is a recognised risk factor for type 2 diabetes and coronary heart disease (CHD). Conversely, weight loss has been shown to improve glycaemic control in patients with type 2 diabetes, as well as to lower the risk of CHD. The traditional pharmacotherapies for type 2 diabetes can further increase weight and this may undermine the benefits of improved glycaemic control. Furthermore, patients' desire to avoid weight gain may jeopardise compliance with treatment, thereby limiting treatment success and indirectly increasing the risk of long-term complications. This review evaluates the influences of established and emerging therapies on bodyweight in type 2 diabetes. Improvement in glycaemic control with insulin secretagogues has been associated with weight gain. On the other hand, biguanides such as metformin have been consistently shown to have a beneficial effect on weight; metformin appears to modestly reduce weight when used as a monotherapy. alpha-Glucosidase inhibitors are considered weight neutral; in fact, the results of some studies show that they cause reductions in weight. Thiazolidinediones (TZDs) are typically associated with weight gain and increased risk of oedema, while the impact of some TZDs, such as pioglitazone, on lipid homeostasis could be beneficial. Insulin, the most effective therapy when oral agents are ineffective, has always been linked to significant weight gain. Newly developed insulin analogues can lower the risk of hypoglycaemia compared with human insulin, but most have no advantage in terms of weight gain. The basal analogue insulin detemir, however, has been demonstrated to cause weight gain to a lesser extent than human insulin. The emerging treatments, such as glucagon-like peptide-1 agonists and the amylin analogue, pramlintide, seem able to decrease weight in patients with type 2 diabetes, whereas dipeptidyl peptidase-4 inhibitors seem to be weight neutral. In summary, while reduction of hyperglycaemia remains the foremost goal in the treatment of patients with type 2 diabetes, the avoidance of weight gain may be a clinically important secondary goal. This is already possible with careful selection of available therapies, while several emerging therapies promise to further extend the options available.
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PMID:Bodyweight changes associated with antihyperglycaemic agents in type 2 diabetes mellitus. 1803 65

Food intake and bodyweight are tightly regulated by the brainstem, hypothalamus and reward circuits. These centres integrate diverse cognitive inputs with humoral and neuronal signals of nutritional status. Our knowledge of the role of gut hormones in this complex homeostatic system has expanded enormously in recent years. This review discusses both the role of gut hormones in appetite regulation, and the current state of development of gut hormone-based obesity therapies, with a particular focus on pancreatic polypeptide, peptide YY, amylin, glucagon-like peptide-1, oxyntomodulin, cholecystokinin and ghrelin. Several gut hormone-based treatments for obesity are under investigation in phase II and III clinical trials, and many more are in the pipeline.
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PMID:Gut hormones as potential new targets for appetite regulation and the treatment of obesity. 1819 23

Body weight is regulated by complex neurohormonal interactions between endocrine signals of long-term adiposity (e.g., leptin, a hypothalamic signal) and short-term satiety (e.g., amylin, a hindbrain signal). We report that concurrent peripheral administration of amylin and leptin elicits synergistic, fat-specific weight loss in leptin-resistant, diet-induced obese rats. Weight loss synergy was specific to amylin treatment, compared with other anorexigenic peptides, and dissociable from amylin's effect on food intake. The addition of leptin after amylin pretreatment elicited further weight loss, compared with either monotherapy condition. In a 24-week randomized, double-blind, clinical proof-of-concept study in overweight/obese subjects, coadministration of recombinant human leptin and the amylin analog pramlintide elicited 12.7% mean weight loss, significantly more than was observed with either treatment alone (P < 0.01). In obese rats, amylin pretreatment partially restored hypothalamic leptin signaling (pSTAT3 immunoreactivity) within the ventromedial, but not the arcuate nucleus and up-regulated basal and leptin-stimulated signaling in the hindbrain area postrema. These findings provide both nonclinical and clinical evidence that amylin agonism restored leptin responsiveness in diet-induced obesity, suggesting that integrated neurohormonal approaches to obesity pharmacotherapy may facilitate greater weight loss by harnessing naturally occurring synergies.
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PMID:Leptin responsiveness restored by amylin agonism in diet-induced obesity: evidence from nonclinical and clinical studies. 1845 26

Contrary to its historical epithet as a lifestyle disorder, obesity is now widely recognized as having a neurobiological basis. This progress is due to our knowledge not only about energy homoeostatic pathways within the central nervous system (CNS), but also about the role of peripheral peptide hormones acting upon the CNS. These hormones include long-term adiposity signals, such as leptin, that inform the CNS primarily of changes in the body's overall fat and energy reserves, and short-term signals such as amylin, peptide YY (PYY) and ghrelin, that primarily reflect changes in the immediate nutritive state (energy intake). The limited weight loss effects achieved with current monotherapy approaches to obesity have been attributed, at least in part, to the redundancies and potent counter-regulatory responses within the neurohormonal feedback loop governing energy balance. Recently, we reported that combinations of amylin, leptin and PYY(3-36) resulted in additive and/or synergistic interactions and caused marked weight loss in the diet-induced obese rat model, which to date has reasonably predicted the clinical effects of several hormones in obese humans. If confirmed in ongoing translational clinical research studies, these findings may provide a physiological rationale for a novel, integrated neurohormonal approach to pharmacotherapy for obesity.
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PMID:Role of islet-, gut-, and adipocyte-derived hormones in the central control of food intake and body weight: implications for an integrated neurohormonal approach to obesity pharmacotherapy. 1847 55

Amylin receptor agonism is emerging as part of an integrated neurohormonal therapeutic approach for managing diabetes mellitus (DM) and body weight. Pramlintide acetate, an analogue of the pancreatic hormone amylin, has been studied in the United States as an antihyperglycemic agent in patients with type 1 or type 2 DM treated with mealtime insulin(1). Further clinical testing of pramlintide in subjects with obesity demonstrated that pramlintide monotherapy induced significant, sustained, and dose-dependent weight loss(2). Recent clinical observations point to its compatibility as a combination therapy with the hormone leptin, eliciting double-digit weight loss in patients with overweight and obesity(3). Herein, we link amylin activation of central neural circuits to these therapeutic effects, and we speculate on other potential therapeutic applications of amylin receptor agonism.
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PMID:Implications of amylin receptor agonism: integrated neurohormonal mechanisms and therapeutic applications. 1927 48

Preptin, a newly isolated 34-amino-acid peptide hormone that is cosecreted with insulin and amylin from pancreatic beta-cells, has emerged as a regulatory element in bone metabolism, but its mechanism remains unclear. We assessed the effects of preptin on proliferation and differentiation of human osteoblasts and investigated the mechanism involved. Our results demonstrated that preptin promoted human osteoblasts proliferation and alkaline phosphatase activity. Suppression of connective tissue growth factor (CTGF), which was upregulated by preptin in a dose- and time-dependent manner, with small interfering RNA (siRNA) abolished the preptin-induced human osteoblasts proliferation and differentiation. Preptin induced activation of ERK mitogen-activated protein kinase (MAPK), but not p38 or JNK in human osteoblasts. Furthermore, pretreatment of human osteoblasts with the ERK inhibitor PD98059 abolished the preptin-induced CTGF secretion and blocked the promoting effect of preptin on osteoblasts proliferation and differentiation. These data demonstrated that preptin is involved in bone anabolism mediated by ERK/CTGF in human osteoblasts and may contribute to the preservation of bone mass observed in hyperinsulinemic states, such as obesity.
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PMID:Connective tissue growth factor is a downstream mediator for preptin-induced proliferation and differentiation in human osteoblasts. 1933 18

Multiple hormones and transmitter systems contribute to glucose homeostasis and the control of metabolism. Recently, the gastrointestinal peptide hormones glucagon-like peptide 1 and amylin have been shown to significantly contribute to this complex physiology. These advances provide the foundation for new treatments for diabetes mellitus. Therapies based on glucagon-like peptide 1 and amylin have now been introduced into clinical practice. Rimonabant, the selective endocannabinoid receptor antagonist, had been used in European countries for the treatment of obesity; it has recently been withdrawn for this indication. This drug exhibited therapeutic benefits for metabolic variables and for type 2 diabetes mellitus. Anesthesia providers caring for patients with diabetes mellitus will need to understand the implications of these new therapies in perioperative settings, particularly with respect to side effects and interactions.
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PMID:New therapeutic agents for diabetes mellitus: implications for anesthetic management. 1944 92

The neurohormonal control of body weight involves a complex interplay between long-term adiposity signals (e.g., leptin), and short-term satiation signals (e.g., amylin). In diet-induced obese (DIO) rodents, amylin/leptin combination treatment led to marked, synergistic, fat-specific weight loss. To evaluate the weight-lowering effect of combined amylin/leptin agonism (with pramlintide/metreleptin) in human obesity, a 24-week, randomized, double-blind, active-drug-controlled, proof-of-concept study was conducted in obese or overweight subjects (N = 177; 63% female; 39 +/- 8 years; BMI 32.0 +/- 2.1 kg/m(2); 93.3 +/- 13.2 kg; mean +/- s.d.). After a 4-week lead-in period with pramlintide (180 microg b.i.d. for 2 weeks, 360 microg b.i.d. thereafter) and diet (40% calorie deficit), subjects achieving 2-8% weight loss were randomized 1:2:2 to 20 weeks of treatment with metreleptin (5 mg b.i.d.), pramlintide (360 microg b.i.d.), or pramlintide/metreleptin (360 microg/5 mg b.i.d.). Combination treatment with pramlintide/metreleptin led to significantly greater weight loss from enrollment to week 20 (-12.7 +/- 0.9%; least squares mean +/- s.e.) than treatment with pramlintide (-8.4 +/- 0.9%; P < 0.001) or metreleptin (-8.2 +/- 1.3%; P < 0.01) alone (evaluable, N = 93). The greater reduction in body weight was significant as early as week 4, and weight loss continued throughout the study, without evidence of a plateau. The most common adverse events with pramlintide/metreleptin were injection site events and nausea, which were mostly mild to moderate and decreased over time. These results support further development of pramlintide/metreleptin as a novel, integrated neurohormonal approach to obesity pharmacotherapy.
Obesity (Silver Spring) 2009 Sep
PMID:Enhanced weight loss with pramlintide/metreleptin: an integrated neurohormonal approach to obesity pharmacotherapy. 1952 51


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