Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Obese hypertensive patients with cardiovascular risk factor clustering have increased plasma nonesterified fatty acid levels and are at high risk for atherosclerotic events. Our previous studies demonstrated that oleic acid induces a mitogenic response in rat aortic smooth muscle cells (RASMCs) through protein kinase C (PKC)- and extracellular signal-regulated kinase (ERK)-dependent pathways. In the present study we investigated the possibility that the generation of reactive oxygen species (ROS) constitutes a critical component of the oleic acid-induced mitogenic signaling pathway in RASMCs. We studied the effect(s) of oleic acid on the generation of ROS using the oxidant-sensitive fluoroprobe 2',7'-dichlorofluorescin diacetate. Relative fluorescence intensity and fluorescent images were obtained with laser confocal scanning microscopy from 1 to 5 minutes, since preliminary studies demonstrated that the peak fluorescence intensity occurred within 5 minutes. Oleic acid (100 micromol/L) induced a time-dependent increase of cell fluorescence that was >8-fold of that seen in control cells at 5 minutes. This was blocked by catalase, which suggests that H2O2 was the principal ROS. The oleic acid-induced increases in H2O2 were blocked when PKC was inhibited with the use of bisindolylmaleimide and when PKC activity was downregulated by exposing RASMCs to phorbol 12-myristate 13-acetate for 24 hours. Stearic and elaidic acids, which are weak PKC activators, did not significantly increase H2O2 production. The increase of H2O2 in response to oleic acid was inhibited by the antioxidant N-acetylcysteine. N-Acetylcysteine also completely blocked ERK activation and the increase of thymidine incorporation in response to oleic acid. The data suggest that generation of H2O2 in RASMCs exposed to oleic acid is PKC dependent. Moreover, H2O2 production emerges as a critical intermediary event in the oleic acid-mediated mitogenic signaling pathway between the activation of PKC and ERK. These observations raise the possibility that the elevated plasma nonesterified fatty acids, including oleic acid, in obese hypertensive patients contribute to vascular growth and remodeling by a PKC-dependent mechanism to generate ROS that subsequently activate ERK.
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PMID:Reactive oxygen species are critical in the oleic acid-mediated mitogenic signaling pathway in vascular smooth muscle cells. 985 64

Human umbilical vein endothelial cells (HUVEC) express functional receptors to leptin, the product of the ob gene. As human obesity is associated with atherosclerosis and hyperleptinemia, we investigated whether leptin, in addition to its angiogenic properties, exerts atherogenic effects through the generation of oxidative stress in endothelial cells. In HUVEC leptin increased the accumulation of reactive oxygen species (ROS), as assessed by the oxidation of 2', 7'- dichlorodihydrofluorescein, in a time- and concentration-dependent manner. In addition, leptin activated the NH2-terminal c-Jun kinase/stress-activated protein kinase pathway as demonstrated by enhanced JNK activity and AP-1 DNA binding. Both effects were sensitive to antioxidant treatment with N-acetylcysteine. NF-kappaB, another redox-sensitive transcription factor, was also activated by leptin stimulation in an oxidant-dependent manner. Finally, activation of both AP-1 and NF-kappaB was associated with an enhanced expression of the monocyte chemoattractant protein-1 in HUVEC. These findings demonstrate that ROS are second messengers involved in leptin-induced signaling in endothelial cells. Thus, chronic oxidative stress in endothelial cells under hyperleptinemia may activate atherogenic processes and contribute to the development of vascular pathology.
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PMID:Leptin induces oxidative stress in human endothelial cells. 1038 13

Treatment of patients with nonalcoholic fatty liver has typically been focused on the management of associated conditions such as obesity, diabetes mellitus, and hyperlipidemia as well as discontinuation of potentially hepatotoxic drugs. Nonalcoholic fatty liver associated with obesity may resolve with weight reduction, although the benefits of weight loss have been inconsistent. Appropriate metabolic control for patients with diabetes mellitus or hyperlipidemia is always recommended but not always effective in reversing nonalcoholic fatty liver. Promising results of pilot studies evaluating ursodeoxycholic acid, gemfibrozil, betaine, N-acetylcysteine, and alpha-tocopherol suggest that these medications may be of potential benefit in the treatment of patients with nonalcoholic fatty liver. These medications, however, need first to be tested in well-controlled trials with clinically relevant end points and extended follow-up. A better understanding of the pathogenesis and natural history of this condition will help to identify the subset of patients with nonalcoholic fatty liver at risk of progressing to advanced liver disease and, hence, the subgroup of patients who should derive the most benefit from medical therapy. In this article, we review (1) the existing medical therapy for patients with nonalcoholic fatty liver, (2) the emerging data from clinical trials evaluating potentially useful medications, and (3) the potential therapeutic implications of recent studies on the pathogenesis of this liver disease.
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PMID:Treatment of nonalcoholic fatty liver: present and emerging therapies. 1129 99

Nonalcoholic fatty liver disease (NAFLD) includes a wide spectrum of liver injury ranging from simple steatosis to steatohepatitis, fibrosis, and cirrhosis. Whereas simple steatosis has a benign clinical course, steatohepatitis is a recognized cause of progressive liver fibrosis and can develop into cirrhosis. NAFLD and nonalcoholic steatohepatitis (NASH) are the two most common chronic liver diseases in United States general population with a prevalence of 20% and 3%, respectively. Hepatic steatosis is frequently associated with obesity, type 2 diabetes, and hyperlipidemia with insulin resistance as a key pathogenic factor. A two-hit theory best describes the progression from simple steatosis to NASH, fibrosis, or cirrhosis. These two hits consist of the accumulation of excessive hepatic fat primarily owing to insulin resistance, and oxidative stress owing to reactive oxygen species (ROS). Mitochondria are the major cellular source of ROS in cases of NASH. Currently, treatment is focused on modifying risk factors such as obesity, diabetes mellitus, and hyperlipidemia. Antioxidants such as vitamin E, N-acetylcysteine, betaine, and others may be beneficial in the treatment of NASH.
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PMID:Nonalcoholic fatty liver disease: pathogenesis and the role of antioxidants. 1229 56

Treatment of patients with non-alcoholic steatohepatitis (NASH) has typically been focused on the management of associated conditions such as obesity, diabetes mellitus and hyperlipidaemia. NASH associated with obesity may resolve with weight reduction, although the benefits of weight loss have been inconsistent. Appropriate control of glucose and lipid levels is always recommended, but is not always effective in reversing the liver condition. Results of pilot studies evaluating ursodeoxycholic acid, gemfibrozil, betaine, N-acetylcysteine, alpha-tocopherol, metformin and thiazolidinedione derivatives suggest that these medications may be of potential benefit for patients with NASH. These medications, however, need first to be tested in well-controlled trials with clinically relevant end-points and extended follow-up. A better understanding of the pathogenesis and natural history of NASH will help to identify the subset of patients at risk of progressing to advanced liver disease and, hence, those patients who should derive the most benefit from medical therapy.
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PMID:Treatment of non-alcoholic steatohepatitis. 1240 46

Treatment of patients with non-alcoholic fatty liver disease (NAFLD) has typically been focused on the management of associated conditions such as obesity, diabetes mellitus and hyperlipidaemia. NAFLD associated with obesity may be resolved by weight reduction, although the benefits of weight loss have been inconsistent. Improving insulin sensitivity with lifestyle modifications or medications usually improves glucose and lipid levels in patients with diabetes and hyperlipidaemia. Improving insulin sensitivity is expected to improve the liver disease but in many diabetic/hyperlipidaemic patients with NAFLD, the appropriate control of glucose and lipid levels is not always accompanied by improvement of the liver condition. Results of pilot studies evaluating ursodeoxycholic acid, gemfibrozil, betaine, N-acetylcysteine, alphatocopherol, metformin and thiazolidinedione derivatives suggest that these medications may be of potential benefit. This article reviews the treatment modalities currently available for patients with NAFLD, including emerging data from clinical trials evaluating promising medications as well as possibilities for the future.
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PMID:Current best treatment for non-alcoholic fatty liver disease. 1273 88

Insulin signaling is enhanced by moderate concentrations of reactive oxygen species (ROS) and suppressed by persistent exposure to ROS. Diabetic patients show abnormally high ROS levels and a decrease in insulin reactivity which is ameliorated by antioxidants, such as N-acetylcysteine (NAC). A similar effect of NAC has not been reported for non-diabetic subjects. We now show that the insulin receptor (IR) kinase is inhibited in cell culture by physiologic concentrations of cysteine. In two double-blind trials involving a total of 140 non-diabetic subjects we found furthermore that NAC increased the HOMA-R index (derived from the fasting insulin and glucose concentrations) in smokers and obese patients, but not in nonobese non-smokers. In obese patients NAC also caused a decrease in glucose tolerance and body fat mass. Simultaneous treatment with creatine, a metabolite utilized by skeletal muscle and brain for the interconversion of ADP and ATP, reversed the NAC-mediated increase in HOMA-R index and the decrease in glucose tolerance without preventing the decrease in body fat. As the obese and hyperlipidemic patients had lower plasma thiol concentrations than the normolipidemic subjects, our results suggest that low thiol levels facilitate the development of obesity. Supplementation of thiols plus creatine may reduce body fat without compromising glucose tolerance.
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PMID:Effect of thiol antioxidant on body fat and insulin reactivity. 1500 12

Treatment of patients with nonalcoholic fatty liver disease (NAFLD) has typically been focused on the management of associated conditions such as obesity, diabetes mellitus and hyperlipidemia. NAFLD associated with obesity may resolve with weight reduction, although the benefits of weight loss have been inconsistent. Appropriate control of glucose and lipid levels is always recommended, but not always effective in reversing the liver condition. Results of pilot studies evaluating ursodeoxycholic acid, gemfibrozil, betaine, N-acetylcysteine, vitamin E (alpha-tocopherol), metformin and thiazolidinedione derivatives suggest that these medications may be of potential benefit for patients with NAFLD. These medications, however, need first to be tested in well-controlled trials with clinically relevant end-points and extended follow up. A better understanding of the pathogenesis and natural history of NAFLD will help to identify the subset of patients at risk of progressing to advanced liver disease, and hence, those patients who should derive the most benefit from medical therapy.
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PMID:Treatment of nonalcoholic fatty liver disease. 1511 91

People with upper body or visceral obesity have a much higher risk of morbidity and mortality from obesity-related metabolic disorders than those with lower body obesity. In an attempt to develop therapeutic strategies targeting visceral obesity, depot- specific differences in the expression of genes in omental and subcutaneous adipose tissues were investigated by DNA array technology, and their roles in adipocyte differentiation were further examined. We found that levels of metallothionein-II (MT-II) mRNA and protein expression were higher in omental than in subcutaneous adipose tissues. The study demonstrates that MT-II may play an important role in adipocyte differentiation of 3T3L1 preadipocytes, and that N-acetylcysteine (NAC) inhibits the adipocyte differentiation of 3T3L1 cells by repressing MT-II in a time- and dose-dependent manner. Furthermore, the intraperitoneal administration of NAC to rats and mice resulted in a reduction of body weights, and a marked reduction in visceral fat tissues. These results suggest that MT-II plays important roles in adipogenesis, and that NAC may be useful as an anti-obesity drug or supplement.
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PMID:Association of anti-obesity activity of N-acetylcysteine with metallothionein-II down-regulation. 1667 70

This study examined whether sucrose-rich diet (SRD)-induced hyperglycaemia, dyslipidemia and oxidative stress may be inhibited by N-acetylcysteine (C(5)H(9)-NO(3)S), an organosulfur from Allium plants. Male Wistar 40 rats were divided into four groups (n=10): (C) given standard chow and water; (N) receiving standard chow and 2 mg/l N-acetylcysteine in its drinking water; (SRD) given standard chow and 30% sucrose in its drinking water; and (SRD-N) receiving standard chow, 30% sucrose and N-acetylcysteine in its drinking water. After 30 days of treatment, SRD rats had obesity with increased abdominal circumference, hyperglycaemia, dyslipidemia and hepatic triacylglycerol accumulation. These adverse effects were associated with oxidative stress and depressed lipid degradation in hepatic tissue. The SRD adverse effects were not observed in SDR-N rats. N-Acetylcysteine reduced the oxidative stress, enhancing glutathione-peroxidase activity, and normalizing lipid hydroperoxyde, reduced glutathione and superoxide dismutase in hepatic tissue of SRD-N rats. The beta-hydroxyacyl coenzyme-A dehydrogenase and citrate-synthase activities were increased in SRD-N rats, indicating enhanced lipid degradation in hepatic tissue as compared to SRD. SRD-N rats had reduced serum oxidative stress and diminished glucose, triacylglycerol, very-low-density lipoprotein (VLDL), oxidized low-density lipoprotein (ox-LDL) and cholesterol/high-density lipoprotein (HDL) ratio in relation to SRD. In conclusion, NAC offers promising therapeutic values in prevention of dyslipidemic profile and alleviation of hyperglycaemia in high-sucrose intake condition by improving antioxidant defences. N-Acetylcysteine had also effects preventing metabolic shifting in hepatic tissue, thus enhancing fat degradation and reducing body weight gain in conditions of excess sucrose intake. The application of this agent in food system via exogenous addition may be feasible and beneficial for antioxidant protection.
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PMID:Effects of N-acetylcysteine on sucrose-rich diet-induced hyperglycaemia, dyslipidemia and oxidative stress in rats. 1681 77


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