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

Malnutrition is still highly prevalent in developing countries. Studies have shown an increase in the number of obese individuals in very poor urban communities. This review shows a co-existence between malnutrition and obesity in households of slums in Brazil and a higher prevalence of stunted/overweight or obese individuals (30%) in comparison with stunted/underweight (16%). These conditions are associated with important metabolic changes. Results from stunted children showed higher susceptibility to the effects of higher fats diets, lower fat oxidation, higher central fat, and higher body fat gain. A model to explain how early malnutrition alters energy balance in adults is outlined. In the presence of a relative food intake insufficiency, a higher cortisol:insulin ratio, associated with lower levels of IGF-1 will lead to lower muscle gain and linear growth, impaired lypolysis and fat oxidation. When these hormonal changes are combined with a higher fat/carbohydrate and/or marked decreased in physical activity, obesity with short stature will occur.
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PMID:Long-term effects of early malnutrition on body weight regulation. 1538 78

Insulin signalling at target tissues results in a large array of biological responses. These events are essential for normal growth and development, and for normal homeostasis of glucose, fat and protein metabolism. Elucidating the intracellular events following activation of the insulin receptor and the interactions between the insulin and IGF-1 signalling systems has been the main focus of a large number of investigators, and for excellent reasons. Improved understanding of the signalling pathways involved in insulin action and the impact of IGF-1 on these processes could lead to a better understanding of the pathophysiology of insulin resistance associated with obesity and type 2 diabetes and the identification of key molecules that could lead to newer and more effective therapeutic agents for treating these common disorders that are already an uprising epidemic of the 21st century. This chapter will summarize our current understanding of the molecular basis of insulin action, beginning with outlining key elements that constitute the insulin signalling pathways. Then, impairments in insulin signalling pathways and new paradigms regarding the molecular basis of insulin and IGF-1 resistance will be analysed.
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PMID:Molecular basis of insulin action. 1556 22

The growth hormone receptor (GHR) is a critical regulator of postnatal growth and metabolism. However, the GHR signaling domains and pathways that regulate these processes in vivo are not defined. We report the first knock-in mouse models with deletions of specific domains of the receptor that are required for its in vivo actions. Mice expressing truncations at residue m569 (plus Y539/545-F) and at residue m391 displayed a progressive impairment of postnatal growth with receptor truncation. Moreover, after 4 months of age, marked male obesity was observed in both mutant 569 and mutant 391 and was associated with hyperglycemia. Both mutants activated hepatic JAK2 and ERK2, whereas STAT5 phosphorylation was substantially decreased for mutant 569 and absent from mutant 391, correlating with loss of IGF-1 expression and reduction in growth. Microarray analysis of these and GHR(-/-) mice demonstrated that particular signaling domains are responsible for the regulation of different target genes and revealed novel actions of growth hormone. These mice represent the first step in delineating the domains of the GHR regulating body growth and composition and the transcripts associated with these domains.
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PMID:In vivo analysis of growth hormone receptor signaling domains and their associated transcripts. 1560 31

Diabetes mellitus and osteoporosis are chronic diseases with an elevated and growing incidence in the elderly. Recent epidemiological studies have demonstrated an elevated risk of hip, humerus and foot fractures in elder diabetic subjects. While type 1 diabetes is generally associated with a mild reduction in bone mineral density (BMD), type 2 diabetes, more prevalent in old subjects, is frequently linked to a normal or high BMD. Studies on experimental models of diabetes have suggested an altered bone structure that may help to explain the elevated risk of fractures observed in these animals and may as well help to explain the paradox of an incremented risk of fractures in type 2 diabetic elderly in the presence of normal or elevated BMD. In addition, diabetic elderly have an increased risk of falls, consequent at least in part to a poor vision, peripheral neuropathy, and weaken muscular performance. Diabetes may affect bone tissue by different mechanisms including obesity, hyperinsulinemia, deposit of advanced glycosilation end products in collagen fibre, reduced circulating levels of IGF-1, hypercalciuria, renal function impairment, microangiopathy and chronic inflammation. A better understanding of these mechanisms may help implement the prevention of fractures in the growing population of mature diabetics.
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PMID:[Osteoporosis and diabetes]. 1564 75

Both growth hormone (GH)/insulin growth factor (IGF)-1 axis and energy balance have been implicated in longevity independently. The aim of the present study was to characterize the effect of a 72-h fasting period at 3 months of age in four different rat strains: (i) Wistar and (ii) Fischer 344 rats, which develop obesity with age, and (iii) Brown Norway and (iv) Lou C rats, which do not. Wistar rats ate more, were significantly bigger, and presented with higher plasma leptin and lower ghrelin levels and hypothalamic growth hormone-releasing hormone (GHRH) content than rats from the three other strains. Plasma insulin and IGF-1 levels were lower in Brown Norway and Lou C rats, and somatostatin content was lower in Brown Norway rats only. Glycaemia was lower in Lou C rats that displayed a lower relative food intake compared to Fischer and Wistar rats. Brown Norway rats showed a greater caloric efficiency than the three other strains. Concerning major hypothalamic neuropeptides implicated in feeding, similar amounts were detected in the four strains for neuropeptide Y, agouti-related peptide, galanin, melanin-concentrating hormone, alpha-melanocortin-stimulating hormone (alpha-MSH) and corticotropin-releasing hormone. Orexin A appeared to be slightly elevated in Fischer rats and cocaine amphetamine-regulated transcript (CART)(55-102) diminished in Brown Norway. At the mRNA level, orexin A, GHSR1, alpha-MSH and CART expression were higher in Wistar and Lou C rats. Principal component analysis confirmed the presence of two main factors in the ad libitum rat population; the first being associated with growth-related parameters and the second being associated with food intake regulation. Hypothalamic GHRH and somatostatin content were positively correlated with feeding-related neuropeptides such as alpha-MSH for GHRH, and orexin A and CART for both peptides. Plasma ghrelin levels were negatively correlated with leptin and IGF-1 levels. Finally, a 72-h fasting period affected minimally body weight, plasma IGF-1 and leptin levels in Lou C rats compared to the three other strains, and plasma insulin levels were less affected in Brown Norway rats. In conclusion, Wistar shorter life span is consistent with its already fatter phenotype at 3 months of age. In terms of IGF-1, glycaemia and leptin responses to fasting, the Lou strain, which presents with a low food intake/body weight and caloric efficiency, is the least affected. The link between food intake regulation, GH axis and ageing is further demonstrated by principal component analysis, where GHRH and somatostatin were found to be strongly associated with energy homeostasis parameters.
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PMID:Plasma and hypothalamic peptide-hormone levels regulating somatotroph function and energy balance in fed and fasted states: a comparative study in four strains of rats. 1566 53

Secretory clusterin protein (sCLU) is a general genotoxic stress-induced, pro-survival gene product implicated in aging, obesity, heart disease, and cancer. However, the regulatory signal transduction processes that control sCLU expression remain undefined. Here, we report that induction of sCLU is delayed, peaking 72 h after low doses of ionizing radiation, and is dependent on the up-regulation of insulin-like growth factor-1 as well as phosphorylation-dependent activation of its receptor (IGF-1 and IGF-1R, respectively). Activated IGF-1R then stimulates the downstream Src-Mek-Erk signal transduction cascade to ultimately transactivate the early growth response-1 (Egr-1) transcription factor, required for sCLU expression. Thus, ionizing radiation exposure causes stress-induced activation of IGF-1R-Src-Mek-Erk-Egr-1 signaling that regulates the sCLU pro-survival cascade pathway, important for radiation resistance in cancer therapy.
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PMID:Delayed activation of insulin-like growth factor-1 receptor/Src/MAPK/Egr-1 signaling regulates clusterin expression, a pro-survival factor. 1568 20

Obesity is a frequent co-morbid condition associated with diffuse idiopathic skeletal hyperostosis (DISH). Serum growth hormone (GH), insulin-like growth factor (IGF-1) and insulin are significantly elevated in patients with DISH. In this study, we examined the relationship between body mass index (BMI) and basal serum GH, IGF-1, and insulin concentration in a group of 36 DISH patients. Basal serum insulin levels were significantly elevated (P<0.001) in DISH patients with a BMI>28 kg m(-2), classified as obese, compared with DISH patients with BMI ranging from 23 to 28 kg m(-2). In addition, BMI strongly positively correlated with serum insulin concentration in DISH patients (adjusted r2 = 0.348, P<0.001). However, BMI did not correlate with either basal serum GH (adjusted r2 = -0.013) or IGF-1 levels (adjusted r2 = -0.010) in DISH. We conclude that BMI does not seem to contribute to elevated serum GH and IGF-1 levels in symptomatic DISH.
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PMID:Body mass index and blood glucose: correlations with serum insulin, growth hormone, and insulin-like growth factor-1 levels in patients with diffuse idiopathic skeletal hyperostosis (DISH). 1570 52

Preeclampsia has been linked to increased risk for cardiovascular disease and, more recently, to reduced risk for breast cancer later in life. The altered chronic disease risk associated with prior preeclampsia may reflect underlying metabolic differences. In this case-control study, we examined the metabolic profiles of older mothers with and without a history of preeclampsia in their first pregnancies. At the time of the study, subjects were non-pregnant, non-smoking women who completed their first pregnancies at age 30 or older, were pre-menopausal, and were free of serious chronic disease. Cases were 13 women who experienced preeclampsia in their first pregnancies; controls were 13 women with uncomplicated first pregnancies, frequency matched to cases on race/ethnicity, current age, and age at delivery. A fasting blood sample was collected from each subject during the luteal phase (day 19-22) of the menstrual cycle and assayed for specific factors thought to be linked to hypertensive disease or breast cancer. Compared to women with uncomplicated pregnancies, those with a history of preeclampsia had significantly elevated levels of fasting serum triglycerides, insulin and glucose, and a higher fasting insulin resistance index, suggesting that women with prior preeclampsia were relatively insulin resistant. In addition, cases had higher levels of insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) and a higher molar ratio of IGFBP-3 to IGF-1 than did controls. Adjustment for obesity and other potential confounders did not appreciably alter the magnitude of these associations. This preliminary study suggests that women with a history of preeclampsia have persistent metabolic abnormalities consistent with their observed excess risk for cardiovascular morbidity and mortality, and their apparent reduced risk for breast cancer later in life.
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PMID:Altered metabolic profiles among older mothers with a history of preeclampsia. 1573 70

Liver fibrosis is the consequence of chronic or repeated liver injury caused by hepatotoxic agents like alcohol and viruses, as well as immune and congenital metabolic disorders. Nonalcoholic fatty liver disease (NAFLD), caused by obesity and abnormal lipid metabolism, may be the latest known cause of liver fibrosis and cirrhosis. Furthermore, NAFLD with obesity can provide a terrain in which alcoholic and viral liver diseases, such as chronic hepatitis C, are prone to cause liver cirrhosis. Insulin, insulin-like growth factor (IGF)-1, peroxisome proliferator-activated receptors (PPARs), leptin, adiponectin, and preadipocyte factor-1/delta-like1 (Pref-1/dlk1) are hormones, growth factors, nuclear receptors, and cytokines that are actively involved in lipid metabolism. They share common target cells important in liver fibrosis, i.e., hepatic stellate cells (HSCs). Activation of HSCs is known to initiate and perpetuate liver fibrosis. Insulin and IGF-1 stimulate HSC activation and collagen production in vitro. However, IGF-1 alleviates liver fibrosis in vivo. Ligands of PPARy inhibit HSC activation and collagen synthesis in vivo and in vitro, and are helpful in decreasing liver fibrosis. But ligands of PPARbeta enhance proliferation of HSCs. Leptin is profibrogenic, and liver fibrosis is decreased in leptin- or leptin receptor-deficient mice. Adiponectin is, on the contrary, anti-fibrogenic. Extensive liver fibrosis may develop in adiponectin-knockout mice and is alleviated by administration of recombinant adiponectin. Pref-1/dlkl is implicated in fibrogenesis of the liver through its modulation of HSCs. The use of such biologically active molecules in lipid metabolism as ligands of PPARgamma and adiponectin might not help slim down a patient on the whole, but can potentially be used to halt the progression of liver fibrosis. Weight reduction, a strategy for controlling obesity and metabolic syndromes, may also be a tool for decreasing NAFLD and alleviating liver cirrhosis.
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PMID:An adipocentric view of liver fibrosis and cirrhosis. 1575 75

The levels of the liporegulatory hormone leptin are increased in obesity, which contributes to the metabolic syndrome; the latter is associated with elevated cardiovascular risk and morbidity. Leptin may play a role in the metabolic syndrome since correlations have been observed between serum leptin levels and several components of the metabolic syndrome. The association of leptinemia and hypertension or diabetes is inconsistent. Leptin levels are higher in females versus males and obese versus lean individuals. We investigated if correlations exist between leptin levels and several indices of the metabolic syndrome in obese and lean Moroccan subjects with (63 males, 129 females) and without (123 males, 234 females) diabetes and/or hypertension. Plasma glucose and insulin and systolic and diastolic blood pressures were higher in obese versus lean individuals. Obesity had no effect on lipid profile, plasma IGF-1, or C-peptide levels. Leptin levels were higher in females versus males and in obese versus lean individuals. The levels correlated significantly with body mass index. Serum leptin concentration did not correlate with either systolic or diastolic blood pressure, although there was a trend for higher blood pressure with increased leptin levels in females. There was no significant difference in leptin levels between NIDDM patients and healthy controls. However, in hypertensive patients, leptin levels were significantly higher in both lean males and females with diabetes as compared to those without diabetes. Similarly, the higher leptin levels paralleled elevated insulin levels in obese nondiabetic males and females, and in male and female diabetics with hypertension. Correlations were observed between leptin levels and C-peptide (an estimate of endogenous insulin secretion), but not with serum IGF-1. The calculated values of HOMA-IR, a marker of insulin resistance, were somewhat higher, parallel with elevated leptin levels, in obese male and female individuals compared to their lean counterparts. There was no relationship between leptin levels and serum lipids. There was a trend for increased serum uric acid levels with higher leptin concentrations. Thus, leptinemia is related to some components of metabolic syndrome, and in turn, it may contribute to the syndrome. This study is novel in that relationships were determined between leptin levels and various indices of metaboli syndrome in a large population of the same ethnic/regional background.
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PMID:Gender-specific leptinemia and its relationship with some components of the metabolic syndrome in Moroccans. 1592 Oct 74


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