166 resultados para LIPOLYSIS
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Unsightly fat knees are a frustrating aesthetic deformity exacerbated by genetic predisposition and resistance to diet. This article reports our experience with laser-assisted lipolysis (LAL) in knee remodelling.
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Gynecomastia is the most common breast pathology. Numerous excisions and liposuction techniques have been described to correct bilateral male breast enlargement. Recently, there has been a shift from the open approach to minimally invasive techniques. This article reports a 5-year experience using laser-assisted lipolysis (LAL) to treat gynecomastia, and describes the surgical technique. Between January 2006 and December 2010, a total of 28 patients with bilateral gynecomastia were treated with LAL. Patients had a mean age of 36.5 years (range 24 to 56 years). LAL was performed with a 980-nm diode laser (continuous emission, 15 W power, 8-12 kJ total energy per breast) after tumescent anesthetic infiltration. The breast was evaluated objectively by two physicians who compared chest circumference and photographs. Patients were also asked to score the results using a visual analogue scale: 75 to 100 (very good), 50-74 (good), 25 to 49 (fair) and 0 to 24 (poor). The postoperative period for all patients was incident-free. After 6 months, 18 patients (64.3%) scored the results as "very good", 6 as "good" (21.4%), 3 as "fair" (10.7%) and 1 "poor" (3.6%). Mean chest circumferences pre- and postoperatively were, respectively, 117.4 ± 11.1 cm and 103.3 ± 7.5 cm (p < 0.001), corresponding to a mean difference of 14.1 cm. Physicians scored the photographs as "very good" in 22 patients (78.6%), as "good" in five patients (17.9%), and as "fair" in one patient (3.6%). LAL in gynecomastia is safe and produces significant effects on fatty tissue, with a reduction in breast volume, together with significant skin tightening. Provided an appropriate amount of energy is delivered by an experienced operator, the results are both significant and consistent.
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The objective was to study changes in plasma leptin concentration parallel to changes in the gene expression of lipogenic- and lipolytic-related genes in adipose tissue of dairy cows around parturition. Subcutaneous fat biopsies were taken from 27 dairy cows in week 8 antepartum (a.p.), on day 1 postpartum (p.p.) and in week 5 p.p. Blood samples were assayed for concentrations of leptin and non-esterified fatty acids (NEFA). Subcutaneous adipose tissue was analysed for mRNA abundance by real-time qRT-PCR encoding for leptin, adiponectin receptor 1 (AdipoR1), adiponectin receptor 2 (AdipoR2), hormones-sensitive lipase (HSL), perilipin (PLIN), lipoprotein lipase (LPL), acyl-CoA synthase long-chain family member 1 (ACSL1), acetyl-CoA carboxylase (ACC), fatty acid synthase (FASN) and glycerol-3-phosphate dehydrogenase 2 (GPD2). Body weight and body condition score of the cows were lower after parturition than before parturition. The calculated energy balance was negative in week 1 and 5 p.p., with higher negative energy balance in week 1 p.p. compared with that in week 5 p.p. On day 1 p.p., highest concentrations of NEFA (353.3 mumol/l) were detected compared with the other biopsy time-points (210.6 and 107.7 mumol/l, in week 8 a.p., and week 5 p.p. respectively). Reduced plasma concentrations of leptin during p.p. when compared with a.p. would favour increasing metabolic efficiency and energy conservation for mammary function and reconstitution of body reserves. Lower mRNA abundance of ACC and FASN expression on day 1 p.p. compared with other biopsy time-points suggests an attenuation of fatty acid synthesis in subcutaneous adipose tissue shortly after parturition. Gene expression of AdipoR1, AdipoR2, HSL, PLIN, LPL, ACSL1 and GPD2 was unchanged over time.
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Perilipin coats the lipid droplets of adipocytes and is thought to have a role in regulating triacylglycerol hydrolysis. To study the role of perilipin in vivo, we have created a perilipin knockout mouse. Perilipin null (peri−/−) and wild-type (peri+/+) mice consume equal amounts of food, but the adipose tissue mass in the null animals is reduced to ≈30% of that in wild-type animals. Isolated adipocytes of perilipin null mice exhibit elevated basal lipolysis because of the loss of the protective function of perilipin. They also exhibit dramatically attenuated stimulated lipolytic activity, indicating that perilipin is required for maximal lipolytic activity. Plasma leptin concentrations in null animals were greater than expected for the reduced adipose mass. The peri−/− animals have a greater lean body mass and increased metabolic rate but they also show an increased tendency to develop glucose intolerance and peripheral insulin resistance. When fed a high-fat diet, the perilipin null animals are resistant to diet-induced obesity but not to glucose intolerance. The data reveal a major role for perilipin in adipose lipid metabolism and suggest perilipin as a potential target for attacking problems associated with obesity.
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Skeletal muscle is a major mass peripheral tissue that accounts for similar to 40% of total body weight and 50% of energy expenditure and is a primary site of glucose disposal and fatty acid oxidation. Consequently, muscle has a significant role in insulin sensitivity, obesity, and the blood-lipid profile. Excessive caloric intake is sensed by the brain and induces beta-adrenergic receptor (beta-AR)- mediated adaptive thermogenesis. beta-AR null mice develop severe obesity on a high fat diet. However, the target gene(s), target tissues(s), and molecular mechanism involved remain obscure. We observed that 30 - 60 min of beta-AR agonist ( isoprenaline) treatment of C2C12 skeletal muscle cells strikingly activated (> 100-fold) the expression of the mRNA encoding the nuclear hormone receptor, Nur77. In contrast, the expression of other nuclear receptors that regulate lipid and carbohydrate metabolism was not induced. Stable transfection of Nur77-specific small interfering RNAs (siNur77) into skeletal muscle cells repressed endogenous Nur77 mRNA expression. Moreover, we observed attenuation of gene and protein expression associated with the regulation of energy expenditure and lipid homeostasis, for example AMP-activated protein kinase gamma 3, UCP3, CD36,adiponectin receptor 2, GLUT4, and caveolin-3. Attenuation of Nur77 expression resulted in decreased lipolysis. Finally, in concordance with the cell culture model, injection and electrotransfer of siNur77 into mouse tibialis cranialis muscle resulted in the repression of UCP3 mRNA expression. This study demonstrates regulatory cross-talk between the nuclear hormone receptor and beta-AR signaling pathways. Moreover, it suggests Nur77 modulates the expression of genes that are key regulators of skeletal muscle lipid and energy homeostasis. In conclusion, we speculate that Nur77 agonists would stimulate lipolysis and increase energy expenditure in skeletal muscle and suggest selective activators of Nur77 may have therapeutic utility in the treatment of obesity.
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Bovine milk contains a lipoprotein lipase that accounts for most, if not all, of its lipolytic activity. The total lipase activity in raw milk is sufficient to cause rapid hydrolysis of a large proportion of the fat. However, in reality this does not happen, because the lipase is prevented from accessing the fat by the milkfat globule membrane. Physical damage to this membrane in raw milk initiates lipolysis. Furthermore, simply cooling certain individual milks soon after secretion can initiate the so-called spontaneous lipolysis. The biochemical basis of spontaneous lipolysis is still poorly understood, but it appears to be related to a balance between activating and inhibiting factors in the milk. Lipolysis in milk and milk products causes rancid off-flavours and other problems, and is a constant concern in the dairy industry. A thorough understanding of the mechanism of lipolysis and constant vigilance by operatives is required to minimize lipase-related problems. (c) 2006 Elsevier Ltd. All rights reserved.
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Obesity is a disease of excess adiposity affecting> 17% of men and >20% of women in Britain. Clinically, it is defined by a Body Mass Index (BMI, kg/m2) of 2:30. Obesity is a confounding factor that promotes insulin resistance, hyperinsulinaemia and type 2 diabetes. Type 2 diabetes accounts for >90% of all cases of diabetes, with a prevalence of 2-6% of adults in most western societies, a majority of which are overweight or obese. Weight loss in obese patients reduces the risk of developing diabetes by >50%. This thesis has investigated the first part of a two-stage therapeutic intervention against obesity in which adipose tissue lipolysis will be combined with increased energy expenditure: the approach is also designed to consider agents that will benefit glycaemic control in coexistent obesity and diabetes by improving insulin sensitivity. Rodent and human in vitro models of adipocyte biology and skeletal muscle have been developed, characterised and evaluated. They include isolated epididymal and parametrial adipocytes of lean and obese diabetic ob/ob mice, cultured 3T3-Ll preadipocytes, isolated human omental and subcutaneous adipocytes and rat L6 cultured muscle cells. Compounds investigated for anti-obesity and anti-diabetic properties include M2 (sibutramine metabolite), 3-guanidinopropionic acid and mazindol. In vivo studies were undertaken to investigate these compounds further in lean and ob/ob mice. In vivo studies indicated that M2 and 3-guanidinopropionic acid reduced body weight gain in ob/ob mice. The three compounds increased lipolysis in adipocytes isolated from lean and ob/ob mice and human adipose depots. The direct action of these compounds was mediated via a pathway involving the f3 adrenoceptors and components of the lipolytic signalling pathway, including protein kinase A and p38 MAP kinase. In addition, M2 and mazindol were capable of increasing glucose uptake into insulin sensitive tissues. M2 and mazindol can act directly on adipose tissue and skeletal muscle to increase glucose uptake via a pathway involving new protein synthesis and activation of the glucose transporters. The M2-stimulated pathway is activated by the conversion of phosphatidylinositol bisphosphate to phosphatidylinositol trisphosphate by phosphatidylinositol 3-kinase. Thus, M2, mazindol and 3-GPA showed pharmacodynamic properties which suggested they might be potential therapeutic treatments for obesity and diabetes.
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The MAC16 tumour produces a factor which exhibits lipid-mobilizing activity in vitro in addition to causing extensive depletion of host lipid stores. The mechanism of the anti-lipolytic effect of two anti-cachectic agents, eicosapentaenoic acid, an ω-3 polyunsaturated fatty acid (PUFA), and N-(3-phenoxycinnamyl)acetohydroxamic acid (BW A4C), a 5-lipoxygenase inhibitor, has been investigated. These two agents reduce tumour growth and reverse the weight loss which accompanies transplantation of the MAC16 murine colon adenocarcinoma into NMRI mice. Mice transplanted with the MAC16 tumour exhibited weight loss which was directly proportional to the serum lipolytic activity measured in vitro up to a weight loss corresponding to 16% of the original body weight. After this time, an inverse relationship between weight loss and lipolytic activity was observed. Body composition analysis revealed a large decrease in body fat relative to other body compartments. The anti-tumour/anti-cachectic effect of EPA did not appear to be due to its ability to inhibit the production of prostaglandin E2. The MAC16 lipolytic factor increased adenylate cyclase activity in adipocyte plasma membranes in a concentration-dependent manner. EPA inhibited the production of cAMP attributed to this lipid-mobilizing factor. EPA produced alterations in Gi , the guanine nucleotide binding protein which mediates hormonal inhibition of adenylate cyclase, in addition to altering cAMP production in adipocyte plasma membranes in response to hormonal stimulation. The alterations in adenylate cyclase activity were complex and not specific to EPA. EPA stimulated adenylate cyclase activity when in a relatively high fatty acid : membrane ratio and inhibited activity when this ratio was lowered. The inhibitory effect of EPA on adenylate cyclase activity may be the underlying mechanism which explains its anti-lipolytic and anti-cachectic effect. The inability of the related ω-3 PUFA, docosahexaenoic acid (DHA), to inhibit cachexia may be due to a difference in the metabolic fates of these two fatty acids. BW A4C inhibited lipolysis in isolated adipocytes which suggests that this compound may possess the potential for an anti-cachectic effect which is independent of its inhibitory effect on tumour growth.
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Loss of adipose tissue in cancer cachexia has been associated with tumour production of a lipid-mobilizing factor (LMF) which has been shown to be homologous with the plasma protein zinc-a2-glycoprotein (ZAG). The aim of this study was to compare the ability of human ZAG with LMF to stimulate lipolysis in vitro and induce loss of body fat in vivo, and to determine the mechanisms involved. ZAG was purified from human plasma using a combination of Q Sepharose and Superdex 75 chromatography, and was shown to stimulate glycerol release from isolated murine epididymal adipocytes in a dose-dependent manner. The effect was enhanced by the cyclic AMP phosphodiesterase inhibitor Ro20-1724, and attenuated by freeze/thawing and the specific ß3-adrenoreceptor antagonist SR59230A. In vivo ZAG caused highly significant, time-dependent, decreases in body weight without a reduction in food and water intake. Body composition analysis showed that loss of body weight could be attributed entirely to the loss of body fat. Loss of adipose tissue may have been due to the lipolytic effect of ZAG coupled with an increase in energy expenditure, since there was a dose-dependent increase in expression of uncoupling protein-1 (UCP-1) in brown adipose tissue. These results suggest that ZAG may be effective in the treatment of obesity.
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Sibutramine is a satiety-inducing serotonin-noradrenaline reuptake inhibitor that acts predominantly via its primary and secondary metabolites. This study investigates the possibility that sibutramine and/or its metabolites could act directly on white adipose tissue to increase lipolysis. Adipocytes were isolated by a collagenase digestion procedure from homozygous lean (+/+) and obese-diabetic ob/ob mice, and from lean nondiabetic human subjects. The lipolytic activity of adipocyte preparations was measured by the determination of glycerol release over a 2-hour incubation period. The primary amine metabolite of sibutramine M2, caused a concentration-dependent stimulation of glycerol release by murine lean and obese adipocytes (maximum increase by 157 ± 22 and 245 ± 1696, respectively, p < 0.05). Neither sibutramine nor its secondary amine metabolite M1 had any effect on lipolytic activity. Preliminary studies indicated that M2-induced lipolysis was mediated via a beta-adrenergic action. The non-selective beta-adrenoceptor antagonist propranolol (10-6M) strongly inhibited M2-stimulated lipolysis in lean and obese murine adipocytes. M2 similarly increased lipolysis by isolated human omental and subcutaneous adipocytes (maximum increase by 194 ± 33 and 136 ± 4%, respectively, p < 0.05) with EC50 values of 12 nM and 3 nM, respectively. These results indicate that the sibutramine metabolite M2 can act directly on murine and human adipose tissue to increase lipolysis via a pathway involving beta-adrenoceptors. © Georg Thieme Verlag KG Stuttgart.
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Peripheral insulin resistance (IR) is one of the main side effects caused by glucocorticoid (GC)-based therapies, and the molecular mechanisms of GC-induced IR are not yet fully elucidated. Thus, we aimed to investigate the effects of dexamethasone treatment on the main components of insulin and inflammatory signaling in the adipose tissue of rats. Male Wistar rats received daily injections of dexamethasone (1mg/kg body weight (b.w.), intraperitoneally (i.p.)) for 5 days (DEX), whereas control rats received saline (CTL). The metabolic status was investigated, and the epididymal fat fragments were collected for lipolysis and western blot analyses. The DEX rats became hyperglycemic, hyperinsulinemic, insulin resistant and glucose intolerant, compared with the CTL rats (P<0.05). The basal glycerol release in the fat fragments was 1.5-fold higher in the DEX rats (P<0.05). The phosphorylation of protein kinase B (PKB) at ser(473) decreased by 44%, whereas, the phosphorylation of insulin receptor substrate (IRS)-1 at ser(307) increased by 93% in the adipose tissue of the DEX rats after an oral bolus of glucose (P<0.05). The basal phosphorylation of c-jun-N-terminal kinase (JNK) and inhibitor of nuclear factor kappa-B (IKKβ) proteins was reduced by 46% and 58%, respectively, in the adipose tissue of the DEX rats (P<0.05). This was paralleled with a significant reduction (47%) in the glucocorticoid receptor (GR) protein content in the adipose tissue of the DEX rats (P<0.05). The insulin-resistant status of rats induced by dexamethasone administration have PKB and IRS-1 activity attenuated in epididymal fat without increases in the phosphorylation of the proinflammatory signals JNK and IKKβ.
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Universidade Estadual de Campinas . Faculdade de Educação Física
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The objective of the present study was to determine the effects of trans-10, cis-12 conjugated linoleic acid (CLA) in adipose tissue explant cultures of growing pigs on the following responses: lipogenesis (measured as rate of C-14-labeled glucose incorporation over a subsequent 2-h incubation in the presence or absence of insulin), lipolysis (release of non-esterified fatty acid over a 2-h incubation in the presence or absence of isoproterenol), activities of lipogenic enzymes, and mRNA abundance of fatty acid synthase (FAS). Adipose tissue explants from nine growing pigs (78 +/- 3 kg) were cultured in 199 medium with insulin, dexamethasone and antibiotics for 4, 12, 24, and 48 h. The treatments were 1) control: 100 mu M polyvinyl alcohol (PVA); 2) pGH: 100 ng/mL porcine growth hormone (pGH) plus 100 mu M PVA; 3) CLA200: 200 mu M trans-10, cis-12 CLA; 4) CLA50: 50 mu M trans-10, cis-12 CLA, and 5) LA: 200 mu M linoleic acid. Fatty acids were added along with PVA (2: 1), respectively, for 24 h. Explants were collected after each culture period and assayed for lipogenesis. Transcripts of FAS mRNA were quantified by real-time RT-PCR after 24 and 48 h. Lipolysis and activities of FAS, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and NADP-malate dehydrogenase were determined after 48 h. As expected, glucose incorporation was decreased (P < 0.05) in response to pGH treatment (positive control). LA had no effect on any parameter evaluated. Treatment with trans-10, cis-12 CLA decreased FAS activity (P < 0.05), but NADPH-generating enzymes were unaffected by treatments. Consistent with reduction in FAS activity, both lipid synthesis and FAS mRNA abundance were reduced with chronic CLA treatment, pGH increased baseline and stimulated lipolysis (P < 0.05) after 48 h of culture, while CLA treatment had no effect on non-esterified fatty acid release. Results of this study showed that trans-10, cis-12 CLA alters lipogenesis but has no effect on lipolysis in cultures of pig adipose tissue.
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Context: Mesotherapy consists of cutaneous injections of a mixture of compounds and has recently been used for cosmetic purposes to reduce local fat and cellulite. To date, several reports have described only local adverse events related to this therapy. We describe the first report of a female patient who developed thyrotoxicosis due to cosmetic mesotherapy with triiodothyroacetic acid in its formulation. Apart from mechanical rupture of the epidermal barrier, a disturbance of type III deiodinase activity or skin fibroblast paracrine function and vascular alterations related to simultaneously injected vasoactive compounds were observed. These findings could be related to thyroid hormone metabolite absorption and systemic consequences in the reported case. Conclusion: We describe factitious thyrotoxicosis induced by mesotherapy, to raise awareness of a systemic adverse effect resulting from this widespread cosmetic practice.