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

Hepatic cholesterol metabolism was studied in operative liver biopsies from 17 morbidly obese subjects and compared with that in samples from 15 nonobese controls. The aim was to understand the mechanisms causing the hypersecretion of cholesterol into bile. The content of cholesteryl esters was increased threefold in the liver of obese subjects compared with that of the controls (P < .0001). The activity and the messenger RNA (mRNA) level of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, the rate limiting enzyme for cholesterol synthesis, were higher in the obese subjects compared with the nonobese subjects (75% and 140%, respectively; P < .01). In the obese subjects, the activity and mRNA level of cholesterol 7alpha-hydroxylase, which regulates the catabolism of cholesterol to bile acids, were also increased by 140% (P < .05) and 180% (P = .06), respectively, as compared with the controls. There was a significant correlation between the activities and the mRNA levels of cholesterol 7alpha-hydroxylase among the obese subjects (r = +0.65, P < .01). The activities of acyl-coenzyme A:cholesterol acyltransferase (ACAT), which governs cholesteryl ester formation, in obese and nonobese patients were 12.5 +/- 1.7 and 8.1 +/- 1.2 pmol/min/mg protein, respectively (P < .05), and the low-density lipoprotein (LDL) receptor mRNA levels were 5.3 +/- 0.7 and 4.5 +/- 0.9 molecules of mRNA/microg of RNA, respectively. We conclude that the activities of three key enzymes in hepatic cholesterol metabolism were increased in morbidly obese subjects compared with nonobese controls, as were mRNA levels of HMG CoA reductase and cholesterol 7alpha-hydroxylase. The mRNA level of the LDL receptor in the obese subjects was not significantly changed. The hypersecretion of cholesterol occurring in obesity is neither due to a reduced conversion of cholesterol to bile acids nor to a decreased esterification of hepatic cholesterol but may be due to an increased synthesis of cholesterol.
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PMID:Hepatic cholesterol metabolism in human obesity. 918 66

Hypertension and diabetes mellitus are common chronic conditions which frequently coexist. Diabetic nephropathy is a major cause of elevated blood pressure in patients with insulin-dependent diabetes mellitus (IDDM). Diabetic nephropathy, arterial sclerosis, obesity and association of essential hypertension can be the causes of hypertension in patients with non-insulin-dependent diabetes mellitus (NIDDM). Ambulatory blood pressure monitoring has revealed that the nocturnal fall of blood pressure is blunted in patients with diabetic nephropathy. A blunted diurnal blood pressure variation is seen in microalbuminuric diabetic patients and even in some normoalbuminuric patients. Accumulating data suggest that normalisation of blood pressure in hypertensive IDDM patients is most important to minimise the loss of kidney function. Angiotensin converting enzyme (ACE) inhibitors have been reported to be effective in postponing the development of nephropathy and in slowing its progression. Whether only ACE inhibitors have such beneficial renal effects on diabetic nephropathy is under discussion. While many studies have suggested that insulin resistance and hyperinsulinaemia are related to an elevated blood pressure in hypertensive patients, there does not seem to be enough evidence to prove that insulin per se can raise blood pressure in humans. Neither an insulin infusion within a physiological range nor sustained hyperinsulinaemia and insulin resistance (e.g. patients with insulinoma, cystic ovary syndrome) have been associated with an elevated blood pressure. Insulin resistance in some hypertensive patients may be a consequence of a decreased blood flow due to an increased peripheral resistance. Preliminary evidence suggests that low birth weight or impaired fetal growth is related to hypertension and NIDDM. Familial clustering of diabetic nephropathy suggests the contribution of genetic susceptibility and/or environmental inheritance. The frequent association of nephropathy with hypertension has led to research on the genes related to hypertension (ACE, angiotensinogen). Nevertheless, to date no reliable and clinically useful genetic marker has been found. Attempts to correct the metabolic abnormalities derived from diabetes are a new topic in the treatment of diabetic nephropathy. The effects of HMG CoA reductase inhibitors (antihypercholesterolaemic drugs), aldose reductase inhibitors (inhibitors of the polyol pathway) and glycation inhibitors (inhibitors of formation of advanced glycosylation end-products) on diabetic nephropathy have been evaluated in animal studies and in some clinical trials. Thus far, results with HMG CoA reductase and aldose reductase inhibitors have been somewhat conflicting. The potential therapeutic role of glycation inhibition in the treatment of diabetes deserves further study.
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PMID:Diabetic nephropathy. Its relationship to hypertension and means of pharmacological intervention. 925 79

Monumental advances in the field of lipid metabolism and its relationship to atherosclerotic cardiovascular disease have been achieved during the last half century. Epidemiologic studies have defined lipid disorders as highly significant independent risk factors for coronary heart disease, along with diabetes mellitus, hypertension and smoking. Primary and secondary prevention studies including the Coronary Primary Prevention Trial, Helsinki Heart Study, and the Coronary Drug Project have shown that lowering the atherogenic low density lipoproteins (LDL) and very low density lipoproteins (VLDL) whilst raising the high density lipoproteins (HDL) significantly decreases the risk for coronary disease. Striking evidence that aggressive therapy (to sharply lower LDL and raise HDL with newer drugs) prevents progression and induces regression of coronary narrowing has been obtained in numerous recent studies using quantitative coronary arteriography. An interesting and unexpected lesson learned from these arteriographic studies was that a highly significant reduction within months in several studies in coronary events was out of proportion to improvements in luminal narrowing. Recently, three major clinical trials to assess the effects of cholesterol reduction by the newly discovered HMG CoA reductase inhibitors (statins) have been published. Pravastatin significantly reduced coronary events in hypercholesterolemic patients [mean LDL-Chol. = 5.0 mM/L (192 mg/dl)] without a history of myocardial infarction. In a secondary prevention study, simvastatin also reduced coronary complications in hypercholesterolemic patients [mean LDL-Chol. = 4.9 mM/L (190 mg/dl)] with pre-existing coronary disease. Very recently, pravastatin treatment significantly reduced coronary events and stroke in patients with a history of myocardial infarction and average cholesterol levels [mean LDL-Chol. = 3.6 mM/L (139 mg/dl)], representing the majority of patients with coronary disease. In all these studies, reduction in cardiovascular events was approximately one-third. In subgroup analyses, men, women, elderly, smokers and hypertensives benefited from cholesterol lowering. There was no significant increase in non-cardiovascular causes of death. In the United States of America, the National Cholesterol Education Program (NCEP) Adult Treatment Panel, representing major health organizations, developed national guidelines on the detection, evaluation and treatment of high blood cholesterol in adults. In a given patient, the Panel recognizes the importance of weighing all cardiovascular disease risk factors including age (men > 45 years, postmenopausal women), family history of premature coronary disease, smoking, hypertension, diabetes and HDL-Cholesterol (< 35 mg/dl) in determining how aggressive therapy should be. The patient with manifest coronary heart disease (CHD) is given a special position as such patients are at highest risk for recurrent events. Major goals of therapy are to lower the LDL-Cholesterol to 2.6 mM/L (< 100 mg/dl) in the CHD patient. In non-CHD patients with two or more risk factors, the LDL-Cholesterol goal is 3.4 mM/L (130 mg/dl). In those with fewer risk factors, the goal is 4.2 mM/L (160 mg/dl). These guidelines should be modified as appropriate for Singapore. Patients with elevated triglycerides usually have low HDL-Cholesterol levels and often represent a heterogeneous group who may have other concurrent abnormalities including the presence of small dense LDL, insulin resistance, hypertension, obesity, overt diabetes and combined hyperlipidemia. Such patients merit individualized treatment. The prevalence of this syndrome may be more common in Singapore and requires further investigation. Current therapeutic guidelines emphasize the need for weight loss and dietary restriction of total and especially saturated fat (< 7% to 10% total calories), cholesterol (< 200 to 300 mg/day), and exercise. (ABSTRACT TRUNCATED)
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PMID:Cholesterol and atherosclerosis: a contemporary perspective. 939 24

The clinical benefit of cholesterol-lowering treatment is unknown in the Japanese elderly in whom the prevalence of morbidity and mortality related to coronary artery disease are known to be low. To evaluate the efficacy of cholesterol-lowering treatment with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor in Japanese elderly patients with documented coronary artery disease, 121 patients with serum cholesterol > or = 150 mg/dl prospectively received HMG-CoA reductase inhibitor, and 271 patients undergoing cholesterol-lowering treatment based on dietary therapy alone served as historical controls. The 143 elderly patients age > or = 65 years in the 2 groups had similar baseline serum total cholesterol level (201 +/- 30 vs 202 +/- 31 mg/dl), age (71 +/- 4 vs 70 +/- 4 years), proportion of men (37/53 vs 64/90), number of diseased vessels (1.7 +/- 0.9 vs 1.5 +/- 1.0), and incidences of other classical coronary risk factors, including hypertension, diabetes mellitus, smoking, obesity and family history of coronary artery disease. In all 392 patients, similar trends were observed, including serum total cholesterol level (208 +/- 33 vs 201 +/- 34 mg/dl). With HMG-CoA reductase inhibitors, serum total cholesterol level was reduced by 14% in the elderly subjects and by 13% in all patients. During the follow-up of approximately 3 years, cardiac events occurred in 5 patients (one elderly) in the treatment group and 38 patients (12 elderly) in the control group. Kaplan-Meier survival estimates revealed a higher event-free survival rate with HMG-CoA reductase inhibitors in the elderly subjects (98% vs 85%, p < 0.05) and in all patients (94% vs 86%, p < 0.05). Cox proportional hazard modeling also demonstrated a significant reduction in risk for cardiac events with drug therapy (relative risk 0.32, p < 0.05), in addition to the number of diseased vessels (relative risk 1.8, p < 0.01). In contrast, no additional risk was observed with advancing age. Cholesterol-lowering treatment with HMG-CoA reductase inhibitors is effective to improve the prognosis of Japanese elderly patients, including those with normal serum cholesterol level.
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PMID:Efficacy of cholesterol-lowering treatment in Japanese elderly patients with coronary artery disease and normal cholesterol level using 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor. 1071 30

Cardiovascular disease (CVD) is the leading cause of death and disability in the United States and in most industrialized nations. Major breakthroughs to modern day cardiovascular/lipid research have been attributed to the findings of the Framingham Heart Study and Gofman and colleagues who made associations between lipoprotein levels (LDL, VLDL and HDL) and CVD. Unfortunately, half of all CVD patients have none of the established coronary risk factors (hypertension, hypercholesterolemia, cigarette smoking, diabetes mellitus, obesity) and new strategies for identifying patients need be considered. Although there remains little disagreement regarding the necessity to lower elevated plasma cholesterol levels, there remains much controversy regarding appropriate dietary means of accomplish this goal. The National Cholesterol Education Program (1993) proposed a dietary reduction (Step I and Step II diets) to the percent saturated fat and cholesterol consumed by at-risk patients. Many currently question about the effectiveness of these diets and an alternative diet, replacing saturated fats by monounsaturated fats (olive oil), has attracted recent attention. While diet modification is considered the foundation of primary treatment, other interventions are frequently required. Although early drug trials demonstrated that agents such as nicotinic acid, clofibrate, gemfibrozil, bile acid-binding resins generally slowed progression of atherosclerotic lesions, lowered plasma cholesterol levels and decreased mortality from CVD, the greatest advance to current drug therapy involved the discovery of the "statins" (HMG-CoA reductase inhibitors). In the current work, mechanisms for vascular dysfunction resulting in myocardial ischemia were explored and potential nutritional (dietary) and pharmacologic interventions were reviewed.
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PMID:Cardiovascular disease: a historic perspective. 1123 77

Pantethine is a versatile and well-tolerated hypolipidemic agent whose efficacy in this regard appears to be mediated by its catabolic product cystamine, a nucleophile which avidly attacks disulfide groups. An overview of pantethine research suggests that the hypotriglyceridemic activity of pantethine reflects cystamine-mediated inhibition of the hepatic acetyl-CoA carboxylase, which can be expected to activate hepatic fatty acid oxidation. Inhibition of HMG-CoA reductase as well as a more distal enzyme in the cholesterol synthetic pathway may account for pantethine's hypocholesterolemic effects. If pantethine does indeed effectively inhibit hepatic acetyl-CoA carboxylase, it may have adjuvant utility in the hepatothermic therapy of obesity. As a safe and effective compound of natural origin, pantethine merits broader use in the management of hyperlipidemias.
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PMID:Inhibition of acetyl-CoA carboxylase by cystamine may mediate the hypotriglyceridemic activity of pantethine. 1135 52

The metabolic syndrome consists of a cluster of metabolic disorders, many of which promote the development of atherosclerosis and increase the risk to develop cardiovascular disease. The metabolic syndrome is characterized by atherogenic dyslipidemia (elevated triglycerides, increased small dense low-density lipoproteins, and decreased high-density lipoproteins), hypertension, insulin resistance and obesity. To decrease the risk of cardiovascular disease events decreasing body weight by ingesting a healthy diet, increasing physical activity, cessation of smoking and managing dyslipidemia are recommended. Pharmacological treatment of dyslipidemia is based on different drug classes. For LDL-cholesterol-lowering mainly statins and for triglyceride-lowering mainly fibrates are used. In primary and secondary prevention trials of heart disease they have shown to reduce the incidence of coronary artery disease or coronary events by 25-60 percent. Statins reduce mainly LDL-cholesterol levels by competitive inhibition of HMG-CoA reductase but have also shown to reduce fasting and postprandial triglyceride levels. Fibrates effectively reduce fasting and postprandial lipemia, shift the distribution of LDL particles towards less dense particles and increase HDL-cholesterol. Thus fibrates particularly address components of the metabolic syndrome and features of diabetic dyslipidemia. However studies still are needed showing definite evidence on differential therapy in lipid lowering based on prospective controlled trials with endpoints of macro- and microangiopathy in diabetic patients.
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PMID:Treatment of dyslipoproteinemia in the metabolic syndrome. 1145 42

An elevated low-density lipoprotein (LDL) cholesterol level is a strong predictor of coronary heart disease (CHD) risk. Over the past seven years, equally strong evidence has accumulated that lowering LDL cholesterol with HMG-CoA reductase inhibitors or statins reduces CHD risk and there is now widespread use of these agents for the primary and secondary prevention of CHD. Treatment issues remain regarding the appropriate degree of LDL cholesterol reduction and whether, in people with very high levels, it would be preferable to achieve the LDL cholesterol goal with a powerful statin alone or combined with an agent that lowers LDL cholesterol by a different mechanism. The main focus in the development of novel agents is the patient with low high-density lipoprotein (HDL) cholesterol, usually associated with hypertriglyceridaemia. Already prevalent as a risk factor for CHD, this abnormality has been linked with insulin resistance, which is likely to increase greatly over the next decade, along with increasing obesity and diabetes. Agents that have potent HDL cholesterol raising capacity include cholesteryl ester transfer protein (CETP) inhibitors, retinoid X receptor (RXR) selective agonists, specific peroxisome proliferator-activated receptor (PPAR) agonists and oestrogen-like compounds. Another area of development involves agents that will lower both cholesterol and triglyceride levels, such as partial inhibitors of microsomal triglyceride transfer protein (MTP) and perhaps squalene synthase inhibitors and agonists of AMP kinase. Future emphasis will be on correcting all lipid abnormalities for the prevention of CHD, not just lowering LDL cholesterol.
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PMID:Novel agents for managing dyslipidaemia. 1177 94

Compelling evidence from meta-analysis of a number of clinical studies on a large aggregate of patients has established an increased level of triglycerides as an independent risk factor for atherosclerotic heart disease. The finding of triglyceride-rich lipoproteins in human atheromata has provided substantial pathophysiologic evidence for a direct role in atherogenesis. Hypertriglyceridemia is commonly embedded in the context of a metabolic syndrome that includes central obesity, insulin resistance, low levels of HDL cholesterol, and often hypertension. Hypertriglyceridemia also appears to underlie the phenomenon of small dense LDL in most instances. Therapeutic interventions must be directed at underlying obesity, insulin resistance, and diabetes when present, as well as addressing metabolic determinants of dyslipidemia per se. Diet, exercise, weight loss, and avoidance of alcohol are the cornerstones of treatment. The choice of medication should be based on the lipoprotein phenotype. Niacin, fibric acid derivatives, and omega-3 fatty acids are most useful in treating severe hypertriglyceridemia. HMG-CoA reductase inhibitors are useful in some phenotypes with moderately increased triglyceride levels. Evidence from a number of clinical trials indicates that mitigation of risk of coronary heart disease, and possibly stroke, can be effected by reducing levels of plasma triglycerides.
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PMID:A risk factor for atherosclerosis: triglyceride-rich lipoproteins. 1179 72

Apolipoprotein (apo) E and C-I are plasma apolipoproteins that have been implicated in the etiology of atherosclerosis and obesity, respectively. Both proteins are synthesized and secreted by macrophages, though pharmacological regulation of their production is poorly understood. The authors compared the effect of 2 HMG-CoA reductase inhibitors, atorvastatin and cerivastatin, on the synthesis and secretion of apoE and apoC-I by THP-1 macrophages. Atorvastatin reduced medium apoE and cellular apoE mRNA of PMA-activated THP-1 cells in a dose-dependent manner (-24% and -22%, respectively, at 1-micromol/L, P < 0.01). ApoC-I in the medium was also reduced by atorvastatin in a dose-dependent manner, though to a lesser extent (-15% at 1-micromol/L, P < 0.05). Cerivastatin similarly reduced medium apoE (-20% at 1-micromol/L, P < 0.05) and cellular apoE mRNA (-31% at 1-micromol/L, P < 0.05), and significantly lowered cellular apoC-I mRNA (-15%, P < 0.05), but not apoC-I in the medium. In experiments with THP-1 macrophages loaded with cholesterol (ie, 24-hour incubation with acetyl-LDL), atorvastatin and cerivastatin (1-micromol/L) significantly (P < 0.05) reduced both medium apoE (-30% and -25%, respectively) and cellular apoE mRNA (-25% and -17%, respectively). A lower and less consistent effect was observed on medium apoC-I (-6% and -18%, respectively) and cellular apoC-I mRNA (-13% and -19%, respectively). These data demonstrate that statins have the capacity to reduce the synthesis and secretion of both apoE and apoC-I in THP-1 macrophages loaded or unloaded with cholesterol.
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PMID:Effect of atorvastatin on ApoE and ApoC-I synthesis and secretion by THP-1 macrophages. 1288 30


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