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Query: UMLS:C0948265 (metabolic syndrome)
 24,271 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of Robert Atkins contributions was to define a diet strategy in terms of an underlying metabolic principle ("the science behind Atkins"). The essential feature is that, by reducing insulin fluxes, lipids are funnelled away from storage and oxidized. Ketosis can be used as an indicator of lipolysis. A metabolic advantage is also proposed: controlled carbohydrates leads to greater weight loss per calorie than other diets. Although the Atkins diet and its scientific rationale are intended for a popular audience, the overall features are consistent with current metabolic ideas. We have used the Atkins controlled-carbohydrate diet as a focal point for teaching nutrition and metabolism in the first-year medical school curriculum. By presenting metabolism in the context of the current epidemic of obesity and of metabolic syndrome and related disorders, we provide direct application of the study of metabolic pathways, a subject not traditionally considered by medical students to be highly relevant to medical practice. We present here a summary of the metabolic basis of the Atkins diet as we teach it to medical students. We also discuss a proposed mechanism for metabolic advantage that is consistent with current ideas and that further brings out ideas in metabolism for students. The topics that are developed include the role of insulin and glucagon in lipolysis, control of lipoprotein lipase, the glucose-glycogen-gluconeogenesis interrelations, carbohydrate-protein interactions and ketosis. In essence, the approach is to expand the traditional feed-fast (post-absorptive) cycles to include the effect of low-carbohydrate meals: the disease states studied are generalized from traditional study of diabetes to include obesity and metabolic syndrome. The ideal diet for weight loss and treatment of metabolic syndrome, if it exists, remains to be determined, but presenting metabolism in the context of questions raised by the Atkins regimen prepares future physicians for critical analysis of clinical and basic metabolic information.
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PMID:Metabolic syndrome and low-carbohydrate ketogenic diets in the medical school biochemistry curriculum. 1837 Jun 62

Severe obesity is increasingly common in the United States. Very obese persons are at increased risk for the metabolic consequences of obesity. A common multidimensional risk condition associated with obesity is the metabolic syndrome. It is accompanied by increased risk for cardiovascular disease and type 2 diabetes. Clinical manifestations of the metabolic syndrome can vary among obese individuals depending on ethnicity and gender. This study was carried out to determine the pattern of metabolic risk factors in very obese women who were considered candidates for bariatric surgery. Twenty-eight women of this type were compared to 28 nonobese women. Among the former, 11 had categorical hyperglycemia (type 2 diabetes), and 26 had metabolic syndrome by current criteria. Both those with and without diabetes had higher triglycerides and lower high-density lipoprotein (HDL) cholesterol levels than nonobese, but their levels were not categorically abnormal. These changes may have been related to observed lower postheparin lipoprotein lipase activities and higher hepatic lipase activities. In spite of lipid changes, apolipoprotein B levels were only marginally higher in very obese women. In contrast to small changes in lipoprotein metabolism, the obese women were severely insulin resistant, as indicated by hyperglycemia and elevated insulin levels. In addition, they had very high C-reactive protein levels. Thus, the metabolic syndrome, which appears to be typical of very obese women, is characterized by insulin resistance, glucose intolerance and a proinflammatory state. Atherogenic dyslipidemia as a metabolic risk factor in contrast is relatively mild. This pattern is more likely to lead to type 2 diabetes prior to development of clinically evident cardiovascular disease.
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PMID:Metabolic syndrome phenotype in very obese women. 1837 Aug 9

The concurrence of visceral obesity, insulin resistance and dyslipidaemia comprises the concept of the metabolic syndrome. The metabolic syndrome is an escalating problem in developed and developing societies that tracks with the obesity epidemic. Dyslipidaemia in the metabolic syndrome is potently atherogenic and, hence, is a major risk factor for CVD (cardiovascular disease) in these subjects. It is globally characterized by hypertriglyceridaemia, near normal LDL (low-density lipoprotein)-cholesterol and low plasma HDL (high-density lipoprotein)-cholesterol. ApoC-III (apolipoprotein C-III), an important regulator of lipoprotein metabolism, is strongly associated with hypertriglyceridaemia and the progression of CVD. ApoC-III impairs the lipolysis of TRLs [triacylglycerol (triglyceride)-rich lipoproteins] by inhibiting lipoprotein lipase and the hepatic uptake of TRLs by remnant receptors. In the circulation, apoC-III is associated with TRLs and HDL, and freely exchanges among these lipoprotein particle systems. However, to fully understand the complex physiology and pathophysiology requires the application of tracer methodology and mathematical modelling. In addition, experimental evidence shows that apoC-III may also have a direct role in atherosclerosis. In the metabolic syndrome, increased apoC-III concentration, resulting from hepatic overproduction of VLDL (very-LDL) apoC-III, is strongly associated with delayed catabolism of triacylglycerols and TRLs. Several therapies pertinent to the metabolic syndrome, such as PPAR (peroxisome-proliferator-activated receptor) agonists and statins, can regulate apoC-III transport in the metabolic syndrome. Regulating apoC-III metabolism may be an important new therapeutic approach to managing dyslipidaemia and CVD risk in the metabolic syndrome.
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PMID:Apolipoprotein C-III: understanding an emerging cardiovascular risk factor. 1839 97

Chronic infection with hepatitis C virus (HCV) can induce insulin resistance (IR) in a genotype-dependent fashion, thus contributing to steatosis, progression of fibrosis and resistance to interferon therapy. The molecular mechanisms in genotype 1 patients that lead to metabolic syndrome are still ambiguous. Based on our current understanding, HCV proteins associate with mitochondria and endoplasmic reticulum and promote oxidative stress. The latter mediates signals involving the p38 mitogen-activated protein kinase and activates nuclear factor kappa B. This transcription factor plays a key role in the expression of cytokines, tumor necrosis factor alpha (TNF-alpha), interleukin 6, interleukin 8, tumor growth factor beta, and Fas ligand. TNF-alpha inhibits the function of insulin receptor substrates and decreases the expression of the glucose transporter and lipoprotein lipase in peripheral tissues, which is responsible for the promotion of insulin resistance. Furthermore, reduced adiponectin levels, loss of adiponectin receptors, and decreased anti-inflammatory peroxisome proliferator-activated receptor alpha in the liver of HCV patients may contribute to reduced fatty acid oxidation, inflammation, and eventually lipotoxicity. This chain of events may be initiated by HCV-associated IR and provides a direction for future research in the areas of therapeutic intervention.
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PMID:Hepatitis C virus infection: molecular pathways to metabolic syndrome. 1875 83

Remnant lipoprotein can be measured by immunoseparation assay and polyacrylamide gel disc electrophoresis; however, these methods have some problems, such as a lack of specificity and being technically complicated. Recently, a new method, the remnant lipoprotein cholesterol homogeneous assay(RemL-C), has been established. In this study, we evaluated the basal performance of RemL-C assay. One hundred and fifty patients with diabetes mellitus were enrolled in this study. RemL-C level was higher in the midband (+) group than in the midband (-) group (p<0.01), and a strong correlation was observed between RemL-C level and remnant lipoprotein level measured by conventional method (r=0.89, p<0.01). RemL-C level correlated positively with triglyceride(TG) (r=0.94, p<0.01) and total cholesterol(TC) (r=0.39, p<0.01), negatively with high density lipoprotein(HDL-C) (r=-0.35, p<0.01) and positively with apolipoprotein (apo) CII, and apoE (apoCII: r=0.59, p<0.01, apoE: r=0.71, p<0.01). In particular, RemL-C level correlated strongly with TG and apoE. RemL-C level was significantly higher in patients with combined hyperlipidemia compared to patients with other hyperlipidemias (p<0.01). When the serum of a patient with combined hyperlipidemia was separated by sepharose 4B gel filtration, the fraction showing peak RemL-C level was observed between the fraction corresponding to VLDL and the fraction corresponding to LDL. Furthermore, the peak of RemL-C corresponded to the peak of apoE. Moreover RemL-C level correlated negatively with preheparin serum lipoprotein lipase mass that is a marker of metabolic syndrome (r=-0.30, p<0.01). These results suggest that the measurement of remnant lipoprotein by RemL-C assay reflects the quantity of intermediate-density lipoprotein. Since RemL-C measurement can be run on an automated clinical analyzer permitting quick and high throughput measurement, RemL-C levels may be useful in the screening of hyperlipidemia.
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PMID:[Remnant lipoprotein cholesterol level measured by homogeneous assay reflects the quantity of intermediate-density lipoprotein]. 1854 84

The number one cause of mortality in the US is cardiovascular related disease. Future predictions do not see a reduction in this rate especially with the continued rise in obesity [P. Poirier, et al., Obesity and cardiovascular disease: pathophysiology, evaluation, and effect of weight loss, Arterioscler Thromb Vasc Biol. 26(5), (2006) 968-976.; K. Obunai, S. Jani, G.D. Dangas, Cardiovascular morbidity and mortality of the metabolic syndrome, Med.Clin. North Am., 91(6), (2007) 1169-1184]. Even so, potential molecular therapeutic targets for cardiac gene delivery are in no short supply thanks to continuing advances in molecular cardiology. However, efficient and safe delivery remains a bottleneck in clinical gene therapy [O.J. Muller, H.A. Katus, R. Bekeredjian, Targeting the heart with gene therapy-optimized gene delivery methods, Cardiovasc Res, 73(3), (2007) 453-462]. Viral vectors are looked upon favorably for their high transduction efficiency, although their ability to elicit toxic immune responses remains [C.F. McTiernan, et al., Myocarditis following adeno-associated viral gene expression of human soluble TNF receptor (TNFRII-Fc) in baboon hearts, Gene Ther, 14(23), (2007) 1613-1622]. However, this high transduction does not necessarily translate into improved efficacy [X. Hao, et al., Myocardial angiogenesis after plasmid or adenoviral VEGF-A(165) gene transfer in rat myocardial infarction model, Cardiovasc Res., 73(3), (2007) 481-487]. Naked DNA remains the preferred method of DNA delivery to cardiac myocardium and has been explored extensively in clinical trials. The results from these trials have demonstrated efficacy in regard to secondary end-points of reduced symptomatology and perfusion, but have failed to establish significant angiogenesis or an increase in myocardial function [P.B. Shah, D.W. Losordo, Non-viral vectors for gene therapy: clinical trials in cardiovascular disease, Adv Genet, 54, (2005) 339-361]. This may be due in part to reduced transfection efficiency but can also be attributed to use of suboptimal candidate genes. Currently, polymeric non-viral gene delivery to cardiac myocardium remains underrepresented. In the past decade several advances in non-viral vector development has demonstrated increased transfection efficiency [O.J. Muller, H.A. Katus, R. Bekeredjian, Targeting the heart with gene therapy-optimized gene delivery methods, Cardiovasc Res, 73(3), (2007) 453-462]. Of these polymers, those that employ lipid modifications to improve transfection or target cardiovascular tissues have proven themselves to be extremely beneficial. Water-soluble lipopolymer (WSLP) consists of a low molecular weight branched PEI (1800) and cholesterol. The cholesterol moiety adds extra condensation by forming stable micellular complexes and was later employed for myocardial gene therapy to exploit the high expression of lipoprotein lipase found within cardiac tissue. Use of WSLP to deliver hypoxia-responsive driven expression of hVEGF to ischemic rabbit myocardium has proven to provide for even better expression in cardiovascular cells than Terplex and has demonstrated a significant reduction in infarct size (13+/-4%, p<0.001) over constitutive VEGF expression (32+/-7%, p=0.007) and sham-injected controls (48+/-7%). A significant reduction in apoptotic values and an increase in capillary growth were also seen in surrounding tissue. Recently, investigations have begun using bioreducible polymers made of poly(amido polyethylenimines) (SS-PAEI). SS-PAEIs breakdown within the cytoplasm through inherent redox mechanisms and provide for high transfection efficiencies (upwards to 60% in cardiovascular cell types) with little to no demonstrable toxicity. In vivo transfections in normoxic and hypoxic rabbit myocardium have proven to exceed those results of WSLP transfections by 2-5 fold [L.V. Christensen, et al., Reducible poly(amido ethylenediamine) for hypoxia-inducible VEGF delivery, J Control Release, 118(2), (2007) 254-261]. This new breed of polymer(s) may allow for decreased doses and use of new molecular mechanisms not previously available due to low transfection efficiencies. Little development has been seen in the use of new gene agents for treatment of myocardial ischemia and infarction. Current treatment consists of using mitogenic factors, described decades earlier, alone or in combination to spur angiogenesis or modulating intracellular Ca2+ homeostasis through SERCA2a but to date, failed to demonstrate clinical efficacy. Recent data suggests that axonal guidance cues also act on vasculature neo-genesis and provide a new means of investigation for treatment.
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PMID:Novel polymer carriers and gene constructs for treatment of myocardial ischemia and infarction. 1866 30

Hypertriglyceridemia is observed in many metabolic diseases such as the metabolic syndrome, diabetes mellitus, or mixed dyslipidemia frequently leading to premature coronary heart disease (CHD). Additionally, several studies have shown that postprandial hypertriglyceridemia is pronounced in patients with CHD, metabolic syndrome, hypertension, and other pathologic conditions. The triglyceride-rich lipoprotein remnants accumulating in the postprandial state seem to be involved in atherogenesis and in events leading to thrombosis. Since abnormal postprandial lipemia is associated with pathologic conditions, its treatment is of clinical importance.Fibrates are of significant help in managing hypertriglyceridemia. This review summarizes the effect of fibric acid derivatives on postprandial lipemia. Fibrates decrease the production of and enhance the catabolism of triglyceride-rich lipoproteins through the activation of peroxisome proliferator-activated receptor-alpha. Results of clinical studies with fibrates have confirmed their action in decreasing postprandial triglyceride levels by increasing lipoprotein lipase activity, decreasing apolipoprotein CIII production, and by increasing fatty acid oxidation in the liver.It is concluded that fibrates are effective agents in lowering the postprandial increase in remnant lipoprotein particles and retinyl palmitate. Furthermore, fibrates can also affect the postprandial lipid profile by increasing hepatic lipase levels and in some cases, by reducing cholesterol ester transfer protein activity. The main target of fibrate therapy is to improve fasting hypertriglyceridemia, which is an essential component associated with improving postprandial lipemia. Fibrates are well tolerated by patients and adverse effects have been reported rarely after their administration.
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PMID:Therapeutic effects of fibrates in postprandial lipemia. 1869 Jul 58

The postprandial hypertriglyceridaemia (PHT) rabbit, developed as a new animal model of metabolic syndrome, is characterized by PHT, central obesity and glucose intolerance. For detailed investigation of lipid metabolism characteristics in PHT rabbit, the plasma levels of apolipoproteins A-I, B, C-II, C-III and E were measured. Movements of apolipoproteins B100 and B48 were investigated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis to determine whether postprandially increased triglyceride is exogenous or endogenous. The level of apolipoproteins A-I, B, C-II and E were increased in PHT rabbit after feeding. Apolipoproteins B100 and B48 were detected in the plasma fraction of d < 1.006 g/mL of the PHT rabbit. The postprandial increase in apolipoprotein B in the PHT rabbit reflects a numerical increase in lipoprotein particles in the blood; the increase in apolipoproteins C-II and E suggests some disturbance in lipoprotein catabolism. Apolipoprotein B48 was detected postprandially in PHT rabbits. These results suggest that delayed catabolism of exogenous lipids caused the retention of chylomicron remnants in the blood. Results also suggest that activities of the lipolytic enzyme lipoprotein lipase and hepatic triglyceride lipase were deficient and that the hepatic uptake of exogenous lipoproteins was delayed in the PHT rabbit. Especially, for examining remnant hyperlipoproteinaemia in humans, PHT rabbit is an excellent animal model for hypertriglyceridaemia research.
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PMID:Kinetic analysis of apolipoproteins in postprandial hypertriglyceridaemia rabbits. 1901 76

Insulin resistance and dyslipidemia are both considered to be risk factors for metabolic syndrome. Low levels of IGF1 are associated with insulin resistance. Elevation of low-density lipoprotein cholesterol (LDL-C) concomitant with depression of high-density lipoprotein cholesterol (HDL-C) increase the risk of obesity and type 2 diabetes mellitus (T2DM). Liver secretes IGF1 and catabolizes cholesterol regulated by the rate-limiting enzyme of bile acid synthesis from cholesterol 7alpha-hydroxylase (CYP7A1). NO-1886, a chemically synthesized lipoprotein lipase activator, suppresses diet-induced insulin resistance with the improvement of HDL-C. The goal of the present study is to evaluate whether NO-1886 upregulates IGF1 and CYP7A1 to benefit glucose and cholesterol metabolism. By using human hepatoma cell lines (HepG2 cells) as an in vitro model, we found that NO-1886 promoted IGF1 secretion and CYP7A1 expression through the activation of signal transducer and activator of transcription 5 (STAT5). Pretreatment of cells with AG 490, the inhibitor of STAT pathway, completely abolished NO-1886-induced IGF1 secretion and CYP7A1 expression. Studies performed in Chinese Bama minipigs pointed out an augmentation of plasma IGF1 elicited by a single dose administration of NO-1886. Long-term supplementation with NO-1886 recovered hyperinsulinemia and low plasma levels of IGF1 suppressed LDL-C and facilitated reverse cholesterol transport by decreasing hepatic cholesterol accumulation through increasing CYP7A1 expression in high-fat/high-sucrose/high-cholesterol diet minipigs. These findings indicate that NO-1886 upregulates IGF1 secretion and CYP7A1 expression to improve insulin resistance and hepatic cholesterol accumulation, which may represent an alternative therapeutic avenue of NO-1886 for T2DM and metabolic syndrome.
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PMID:NO-1886 suppresses diet-induced insulin resistance and cholesterol accumulation through STAT5-dependent upregulation of IGF1 and CYP7A1. 1981 88

Insulin resistance is partly due to suppression of insulin-induced glucose uptake into adipocytes. The uptake is dependent on adipocyte differentiation, which is controlled at mRNA transcription level. The peroxisome proliferator-activated receptor (PPAR), a ligand-regulated nuclear receptor, is involved in the differentiation. Many food-derived compounds serve as ligands to activate or inactivate PPAR. In this study, we demonstrated that bixin and norbixin (annatto extracts) activate PPARgamma by luciferase reporter assay using GAL4-PPAR chimera proteins. To examine the effects of bixin on adipocytes, 3T3-L1 adipocytes were treated with bixin or norbixin. The treatment induced mRNA expression of PPARgamma target genes such as adipocyte-specific fatty acid-binding protein (aP2), lipoprotein lipase (LPL), and adiponectin in differentiated 3T3-L1 adipocytes and enhanced insulin-dependent glucose uptake. The observations indicate that bixin acts as an agonist of PPARgamma and enhances insulin sensitivity in 3T3-L1 adipocytes, suggesting that bixin is a valuable food-derived compound as a PPAR ligand to regulate lipid metabolism and to ameliorate metabolic syndrome.
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PMID:Bixin regulates mRNA expression involved in adipogenesis and enhances insulin sensitivity in 3T3-L1 adipocytes through PPARgamma activation. 1989 58


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