UMLS:C0948265 - FACTA Search

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

Atherosclerosis, coronary artery disease and elevated serum cholesterol are frequently associated with an abnormal pattern of androgen metabolites, especially an elevation of etiocholanolone (E) and/or epiandrosterone (EA) relative to androsterone (A). Therapeutic correction of these metabolic defects may lower serum cholesterol. We have attempted to reproduce this metabolic syndrome in rats by altering their endocrine status. Intact male rats excreted very little A or E in their bile; more than 80% of the [4-14C]A-dione was excreted as unknown polar compounds. Adrenalectomy, thyroidectomy or streptozotocin diabetes induced little or no change in the excretion of both E and A and did not alter the A/E ratio. Hypophysectomy (hypox), however, resulted in a huge increase in E excretion and a 10-fold decrease in the A/E ratio. Treatment of hypophysectomized males with bovine growth hormone (bGH) but not testosterone or thyroxine restored the pattern of androgen metabolites to that of intact male rats. Intact female rats excreted mainly A, and this was decreased by ovariectomy. Hypophysectomy, however, resulted in a marked increase in E and a corresponding large decrease in A excretion. Treatment of hypox females with estradiol or triiodothyronine did not correct the metabolic defects in A and E production, whereas GH resulted in a pattern of A-dione metabolism resembling that of intact males; i.e., primarily polar metabolites with low A and E. Hypophysectomy thus results in a dramatic increase in 5 beta-reductase activity in male and female rats. GH therapy restores the metabolic pathway to that seen in intact males. Our objective had been to find a model capable of detecting substances which would increase A and decrease E production. The male rat (regardless of endocrine status) has little 5 alpha-reductase activity. The intact female rat, however, has high 5 alpha-reductase activity, and retains significant 5 alpha-reductase in the absence of the ovaries. In hypox females, 5 alpha-reductase was much reduced while 5 beta-reductase was increased. Furthermore, serum cholesterol was elevated in hypox females but could be lowered by exogenous androsterone. Thus the hypox female rat appears to offer the best model for identifying non-hormonal agents which could enhance the production of A and/or decrease the production of E. Such agents might favorably influence cholesterol metabolism.
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PMID:Effects of altered endocrine function on biliary metabolites of [4-14C]androst-4-ene-3,17-dione in rats. Possible utility as a model for identifying anti-atherosclerotic agents. 399 76

The triglyceride (TG) level is one of several lipid parameters that can aid prediction of coronary heart disease (CHD) risk. An elevated plasma TG level is strongly associated with an increased risk of CHD. Hypertriglyceridemia, the second most common dyslipidemic abnormality in hypertensive subjects after increased low-density lipoprotein cholesterol (LDL-C), is defined by the National Cholesterol Education Programme (NCEP) as a fasting TG level of > 2.26 mmol/l (> 200 mg/dl) and is recognised as a primary indicator for treatment in type IIb dyslipidemia. Raised TG levels can be present in individuals at risk for CHD when the total cholesterol is normal. However, not all individuals with raised TG levels have increased risk of CHD. Factors such as: diet, age, lifestyle, and a range of medical conditions, drug therapy and metabolic disorders, can all affect the TG level. In some of these circumstances, other factors protect against the risk of CHD, and can minimise or negate the effect of the risk factors present. Although TG reducing therapy has been shown to be associated with an improved clinical outcome, more research is needed to determine whether this is an independent effect of TG reduction or an effect of normalising the overall lipid profile in hypertriglyceridemic patients. Further trials are required to quantify the clinical benefits of lowering TG to 'target' levels and to confirm targets defined by NCEP-II (shown in Table 1). The role of TG in CHD pathogenesis is thought to involve several direct and indirect mechanisms, such as effects on the metabolism of other lipoproteins, transport proteins, enzymes, and on coagulation and endothelial dysfunction. More research is required to fully elucidate the role of TG, the ways in which it can influence other risk factors and the mechanism of its own more direct role in the atherogenic process. Patients with hypertriglyceridemia have been shown to respond well to dietary control and to the use of lipid lowering drugs such as 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG CoA) reductase inhibitors (known as statins), fibrates and nicotinic acids. However, recent retrospective real-life clinical studies show that only 38% of patients receiving some form of lipid-lowering therapy achieved NCEP-defined LDL-C target levels, demonstrating the need for the use of more aggressive treatment. In hypertriglyceridemic patients, the newer statins, cerivastatin and atorvastatin, have shown comparable efficacy in reducing TG compared with the older statins. Achieving NCEP target lipid levels has been shown to reduce the risk of cardiovascular disease in dyslipidemic individuals, including high-risk patient groups such as those with additional risk factors, existing heart disease, diabetes mellitus and metabolic syndrome. Although the latest clinical studies investigating combination therapies, i.e. dual therapy with both a statin and a fibrate, have demonstrated them to be effective for overall control of lipid parameters and reducing coronary events, it is not yet clear whether this offers any significant advantage over monotherapy. Results from ongoing longer-term end-point clinical studies may provide further information in this area and consequent reviews of primary care management policies for dyslipidemia. Statin monotherapy may be a reliable option for primary care treatment of dyslipidemia (including hypertriglyceridemia).
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PMID:Hypertriglyceridemia: a review of clinical relevance and treatment options: focus on cerivastatin. 1146 48

The metabolic syndrome is a complex constellation of disorders, each one a significant risk factor for the development of cardiovascular disease (CVD). The increasing prevalence of this condition is a major concern for healthcare providers both in Europe and North America. The concern surrounding the prevalence of the metabolic syndrome is reflected in the recently published National Cholesterol Education Program Adult Treatment Panel III guidelines. Although complex in nature, the individual components of the metabolic syndrome appear to be linked by the presence of insulin resistance. Concurrently treating the underlying insulin resistance along with the complex array of other disorders should form the core of any management strategy. Treatment of atherogenic dyslipidaemia should be a major aim, since it is associated with a significant risk of CVD. While lifestyle modifications form the cornerstone of any dyslipidaemia management strategy, many patients require the addition of lipid-modifying drugs. Several agents are available for the treatment of lipid abnormalities, including fibrates, bile acid sequestrants, niacin and hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins). Of these, statins should be used as the first treatment option in the majority of patients because they are efficacious for reducing low-density lipoprotein cholesterol, are effective across the lipid profile and are well tolerated in the majority of cases. Furthermore, the American Diabetes Association (ADA) recommends statins as first-line pharmacological treatment of dyslipidaemia in patients with diabetes mellitus. This review discusses the diagnosis and management of the metabolic syndrome and examines the potential of future treatment options.
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PMID:The metabolic syndrome: targeting dyslipidaemia to reduce coronary risk. 1266 9

Two isoforms of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) interconvert the active glucocorticoid, cortisol, and inactive cortisone. 11beta-HSD1 acts predominantly as an oxo-reductase in vivo using NADP(H) as a cofactor to generate cortisol. In contrast, 11beta-HSD2 is a NAD-dependent dehydrogenase inactivating cortisol to cortisone, thereby protecting the mineralocorticoid receptor from occupation by cortisol. In peripheral tIssues, both enzymes serve to control the availability of cortisol to bind to corticosteroid receptors. 11beta-HSD2 protects the mineralocorticoid receptor from cortisol excess; mutations in the HSD11B2 gene explain an inherited form of hypertension, the syndrome of 'apparent mineralocorticoid excess', in which 'Cushing's disease of the kidney' results in cortisol-mediated mineralocorticoid excess. Inhibition of 11beta-HSD2 explains the mineralocorticoid excess state seen following liquorice ingestion and more subtle defects in enzyme expression might be involved in the pathogenesis of 'essential' hypertension. 11beta-HSD1 by generating cortisol in an autocrine fashion facilitates glucocorticoid receptor-mediated action in key peripheral tIssues including liver, adipose tissue, bone and the eye. 'Cushing's disease of the omentum' has been proposed as an underlying mechanism in the pathogenesis of central obesity and raises the exciting possibility of selective 11beta-HSD1 inhibition as a novel therapy for patients with the metabolic syndrome. 'Pre-receptor' metabolism of cortisol via 11beta-HSD isozymes is an important facet of corticosteroid hormone action. Aberrant expression of these isozymes is involved in the pathogenesis of diverse human diseases including hypertension, insulin resistance and obesity. Modulation of enzyme activity may offer a future therapeutic approach to treating these diseases whilst circumventing the endocrine consequences of glucocorticoid excess or deficiency.
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PMID:Tissue-specific Cushing's syndrome, 11beta-hydroxysteroid dehydrogenases and the redefinition of corticosteroid hormone action. 1294 16

Glucocorticoids (GCs) are a vital class of steroid hormones that are secreted by the adrenal cortex and that are regulated by ACTH largely under the control of the hypothalamic-pituitary-adrenal axis. GCs mediate profound and diverse physiological effects in vertebrates, ranging from development, metabolism, neurobiology, anti-inflammation and programmed cell death to many other fuctions. Multiple factors "downstream" of GC secretion, such as glucocorticoid receptor (GR) number and the abundance of plasma binding proteins have originally been considered as modulators of GC action. However, in the last decade the role of tissue-specific GC activating and inactivating enzymes have been identified as additional determinants in GC signalling pathways. On the cellular level, they function as important pre-receptor regulators by acting as "molecular switches" for receptor-active and receptor-inactive GC hormones. According to their biologic activity to catalyze the interconversion of C11-hydroxyl and C11-oxo GCs these enzymes have been named 11beta-hydroxysteroid dehydrogenase (11beta-HSD; EC 1.1.1.146). Two isoforms of 11beta-HSD have been cloned and characterized so far. 11beta-HSD type 1 is found in a wide range of tissues, acts predominantly as a reductase in intact cells and tissues by regenerating active cortisol from cortisone, and has been described to regulate GC access to the GR. 11beta-HSD type 2 is found mainly in mineralocorticoid target tissues such as kidney and colon, acts only as a dehydrogenase by producing inactive cortisone, and has been found to protect the mineralocorticoid receptor from high levels of receptor-active cortisol. Recently, 11beta-HSD 1 has become highly topical due to the finding that 11beta-HSD 1 plays a pivotal role in the pathogenesis of central obesity and the appearance of the metabolic syndrome. This review provides an overview on the components involved in GC signalling of 11beta-HSD type 1 as an important pre-receptor control enzyme that modulates activation of the GR.
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PMID:Enzymology and molecular biology of glucocorticoid metabolism in humans. 1460 13

Plasma levels of high-density lipoprotein-cholesterol (HDL-C) are a powerful independent cardiovascular risk factor, bearing an inverse relationship with atherosclerotic cardiovascular disease (with risk rising sharply when levels are <1.04 mmol/L). Apart from its protective role in atherosclerosis, HDL-C increases fibrinolysis, is an antioxidant to low density lipoprotein-cholesterol (LDL-C), and decreases platelet aggregability. Up to a third of patients with atherosclerotic cardiovascular disease have 'desirable' plasma levels of total cholesterol but low HDL-C levels. Benefits of treating low plasma HDL-C levels were clearly demonstrated in the Veterans Affairs HDL Intervention Trial (VA-HIT) where gemfibrozil reduced nonfatal infarcts and coronary deaths by 22%. This was achieved by a 6% increase in plasma HDL-C levels, and a 24.5% decrease in plasma levels of triglycerides, without any significant decrease in LDL-C levels. Multivariate analyses revealed the rise in plasma HDL-C levels after treatment, but not decreases in plasma levels of triglycerides or LDL-C, predicted coronary artery disease events. The typical patient under consideration in this article is one with plasma levels of HDL-C <1 mmol/L, LDL-C <3.37 mmol/L [either receiving therapeutic lifestyle changes or or LDL-C-lowering therapy comprising a hydroxymethylglutaryl coenzyme-A (HMG-CoA) reductase inhibitor or bile acid sequestrant] and fasting triglycerides <2.26 mmol/L. We propose this dyslipidemia be classified as Type VI phenotype following the Frederickson and Lees classification. High-risk patients (with >/=2 risk factors for atherosclerotic cardiovascular disease, or 10-year cardiovascular risk >20%), patients with established atherosclerotic cardiovascular disease, or type 2 diabetes mellitus, or metabolic syndrome should receive pharmacotherapy. Plasma HDL-C levels >1.16 mmol/L may be considered optimal and between 1 and 1.16 mmol/L as desirable. Fibric acid derivatives, nicotinic acid, HMG-CoA reductase inhibitors, estrogens, and ethanol (not recommended as therapy) increase plasma HDL-C levels. Nicotinic acid is the most potent agent and recent reports indicate that, in contrast to gemfibrozil, it selectively increases antiatherogenic HDL subfraction, lipoprotein (Lp) AI (without apolipoprotein AII), in patients with low plasma HDL-C levels. An extended-release formulation, administered once daily, has improved the tolerability of nicotinic acid. Recent evidence also indicates that nicotinic acid may effectively correct dyslipidemia in patients with diabetes mellitus without significantly compromising glycemic control. Fibric acid derivatives and estrogen raise plasma HDL-C levels by different mechanisms of action, and these agents may be used with nicotinic acid. Combination therapy (especially HMG-CoA reductase inhibitor and nicotinic acid) should be considered in patients with atherosclerotic cardiovascular disease and low plasma HDL-C levels.
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PMID:Optimal therapy of low levels of high density lipoprotein-cholesterol. 1472 46

Combined hyperlipidemia is increasing in frequency and is the most common lipid disorder associated with obesity, insulin resistance and diabetes mellitus. It is associated with other features of the metabolic syndrome including hypertension, hyperuricemia, hyperinsulinemia and highly atherogenic subfractions of lipoprotein remnant particles including small dense low density lipoprotein-cholesterol. This review examines the mechanisms by which combined hyperlipidemia arises and the various drugs including fibric acid derivatives, hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, and nicotinic acid which can be used either as monotherapy or in combination to manage it and to improve prognosis from atherosclerotic disease in diabetes mellitus, insulin resistant states and primary combined hyperlipidemia. The therapeutic approach to combined hyperlipidemia involves determination of whether the cause is hepatocyte damage or metabolic derangements. Combined hyperlipidemia due to hepatocyte damage should be treated by attention to the primary cause. In the case of metabolic dysfunction because of imbalance in glucose and fat metabolism, therapy of diabetes mellitus and obesity should be optimised prior to commencement of lipid lowering drugs. Both fibric acid derivatives and HMG-CoA reductase inhibitors can be used in the treatment of combined hyperlipidemia with fibric acid derivatives having greater effects on triglycerides and HMG-CoA reductase inhibitors on LDL-C though both have effects on the other cardiovascular risk factors. There is some evidence of benefit with both interventions in mild combined hyperlipidemias and large scale trials are underway. Fibric acid derivatives and HMG-CoA reductase inhibitor therapy can be combined with care, provided that gemfibrozil is avoided, fibric acid derivatives are given in the mornings and shorter half -life HMG-CoA reductase inhibitors are used at night. Combined hyperlipidemia emergencies occur with predominant hypertriglyceridemia in pregnancy or as a cause of pancreatitis. Therapy in the former should aim to reduce chylomicron production by a low fat diet and intervention to suppress VLDL-C secretion using omega-3 fatty acids. In the latter case, fluid therapy alone and medium chain plasma triglyceride infusions usually reduce levels satisfactorily though apheresis may be required. Blood glucose levels also need aggressive management in these conditions. Combined hyperlipidemia is likely to become an increasing problem with the increase in the prevalence of obesity and diabetes mellitus and needs aggressive management to reduce cardiovascular risk.
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PMID:Drug treatment of combined hyperlipidemia. 1472 15

Homocysteine is an intermediate product in the methionine metabolism, which is catalysed by several enzymes with B2, B6, B12 vitamins and folic acid as cofactors. Moderate hyperhomocysteinemia, defined as total homocysteine concentration between 12 to 30 micromol/l, represents an independent risk factor for heart disease, vascular brain disease, phlebothrombosis and thromboembolic complications. It is related to placental abruptions, spina bifida and some neuropsychiatric disorders. Hyperhomocysteinemia is a metabolic syndrome based on interaction between genetic factors (most frequently 677C/T polymorphism of methylentetrahydrofolate reductase), diseases and demographic factors (smoking, aging, hormonal and nutritional factors). Moderate hyperhomocysteinemia occurs in about 20 to 30% of patients with clinical complications of atherosclerosis. Prospective and genetic studies have shown, that moderate hyperhomocysteinemia in healthy persons is only a weak predictor of cardiovascular diseases. Contrary to it, in patients with ischaemic heart disease, renal failure or diabetes mellitus and in thromboembolic disease, hyperhomocysteinemia represents a strong predictor of vascular morbidity and mortality. Toxic effects of hyperhomocysteinemia on the vascular wall can be explained by a chemical modification of lipoproteins and vascular structure, oxidative stress, endothelial dysfunction, inadequate endothelial cell regeneration, smooth muscle cell proliferation or by an accumulation of functionally non sufficient connective tissue. Also thrombogenic effects or an increased expression of cholesterol level controlling proteins and fatty acids in the liver can be considered. Treatment of hyperhomocysteinemia is based on the administration of pharmacological doses of folic acid, B6 and B12 vitamins, which can decrease total homocysteine concentration by 25 to 30%. Such decrease, which is in average 3 micromol/l, results in the decrease of relative risk of ischaemic heart disease by 11 to 16%, phlebothrombose by 25% and vascular brain diseases by 19 to 24%.
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PMID:[Consequences of moderate hyperhomocysteinemia in internal medicine]. 1530 62

11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) interconverts inactive cortisone and active cortisol. Although bidirectional, in vivo it is believed to function as a reductase generating active glucocorticoid at a prereceptor level, enhancing glucocorticoid receptor activation. In this review, we discuss both the genetic and enzymatic characterization of 11beta-HSD1, as well as describing its role in physiology and pathology in a tissue-specific manner. The molecular basis of cortisone reductase deficiency, the putative "11beta-HSD1 knockout state" in humans, has been defined and is caused by intronic mutations in HSD11B1 that decrease gene transcription together with mutations in hexose-6-phosphate dehydrogenase, an endoluminal enzyme that provides reduced nicotinamide-adenine dinucleotide phosphate as cofactor to 11beta-HSD1 to permit reductase activity. We speculate that hexose-6-phosphate dehydrogenase activity and therefore reduced nicotinamide-adenine dinucleotide phosphate supply may be crucial in determining the directionality of 11beta-HSD1 activity. Therapeutic inhibition of 11beta-HSD1 reductase activity in patients with obesity and the metabolic syndrome, as well as in glaucoma and osteoporosis, remains an exciting prospect.
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PMID:11beta-hydroxysteroid dehydrogenase type 1: a tissue-specific regulator of glucocorticoid response. 1546 42

1. Expression levels of four key enzymes of cholesterol metabolism, namely 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, lanosterol 14-demethylase (CYP51), cholesterol 7alpha-hydroxylase (CYP7A1) and sterol 12alpha-hydroxylase (CYP8B1), in metabolic syndrome model rats (SHR/NDmcr-cp) were examined. 2. Decreased expression of CYP51, which may be linked to the development of obesity, was found in the rats. 3. Expression of CYP8B1 was significantly higher in young rats. 4. No substantial change was observed in the mRNA levels of the dominant rate-limiting enzymes of sterol metabolism, namely HMG-CoA reductase and CYP7A1, in the rats. 5. These findings suggest that the expression levels of two key enzymes managing the downstream parts of the cholesterol-metabolizing pathways are altered in the rats, although little change was observed in the expression levels of the dominant rate-limiting enzymes of cholesterol metabolism.
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PMID:Studies on the expression levels of sterol-metabolizing enzymes in the obese model SHR/NDmcr-cp rats. 1564 92

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