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Query: UMLS:C0242339 (dyslipidemia)
 13,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Niacin (nicotinic acid) in large doses (> 2 g) has been increasingly the choice of lipid-lowering agent by clinicians. However, the potential risks of the use of high doses of the vitamin have not been critically considered in the same way as has the use of other lipid-lowering drugs. The present study provides evidence that pharmacological levels of niacin interfere with the metabolism of methionine, leading to hyperhomocysteinemia and hypocysteinemia. Male Sprague-Dawley rats were fed a semisynthetic diet supplemented with either 400 or 4000 mg niacin/kg (compared with 47 mg/kg diet in the control diet). In Experiment 1, feeding these diets for 3 wk resulted in a dose-related increase in the plasma and urine methionine concentrations while cysteine levels were decreased. This altered methionine metabolism was accompanied by a lower plasma vitamin B-6 concentration in niacin-supplemented rats compared with controls. In Experiment 2, the methionine and cysteine levels in plasma and urine were normalized when vitamin B-6 (10 mg/kg diet) was added to the diet containing 4000 mg niacin/kg and fed for 6 wk. This experiment also showed that plasma and urine homocysteine concentrations were increased by niacin and normalized by vitamin B-6. The hypolipidemic action of niacin was unaffected by the presence of vitamin B-6. These results indicate that niacin at large dosages interferes with methionine metabolism by affecting vitamin B-6 status. The treatment of dyslipidemia with simultaneous administration of niacin and vitamin B-6 could be a better therapy than the use of niacin alone.
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PMID:Vitamin B-6 normalizes the altered sulfur amino acid status of rats fed diets containing pharmacological levels of niacin without reducing niacin's hypolipidemic effects. 904 May 54

Non-insulin-dependent diabetes mellitus (NIDDM) is associated with approximately two fold increase in coronary heart disease (CHD) in men and fourfold increase in CHD in women. In most studies, the duration of diabetes and severity of glycemia are only weakly related to CHD in NIDDM, suggesting that the prediabetic period may be important for the increased CHD in NIDDM subjects. Both hyperinsulinemia and/or insulin resistance predict the development of NIDDM. A number of studies have shown that increased cardiovascular risk factors (especially high triglyceride, blood pressure, and small dense low-density lipoprotein (LDL) and low high-density liproprotein (HDL) cholesterol) precede the onset of NIDDM. Recent data from the San Antonio Heart Study suggest that the atherogenic pattern of cardiovascular risk factors is more marked in prediabetic women than in prediabetic men, thus partially explaining the higher risk of CHD in prediabetic women than in prediabetic men. The atherogenic changes in cardiovascular risk factors appear to be mainly due to increased hyperinsulinemia and insulin resistance in nondiabetic subjects. Interventions to reduce cardiovascular disease in NIDDM subjects should emphasize the primary prevention of NIDDM and very aggressive treatment of traditional cardiovascular risk factors in prediabetic subjects. Treatment of hypertension and dyslipidemia in high-risk patients for NIDDM should avoid agents that further worsen insulin resistance (nicotinic acid, beta blockers, and thiazides), as subjects with hypertension and dyslipidemia are already at increased risk of NIDDM.
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PMID:The prediabetic problem: development of non-insulin-dependent diabetes mellitus and related abnormalities. 910 90

Patients with diabetes mellitus have an increased risk for coronary artery disease due to hyperglycemia, hypertension, dyslipidemia, and other risk factors. The diabetic dyslipidemia in these patients is characterized by moderately high levels of (1) serum cholesterol and triglycerides; (2) small, dense low-density lipoprotein (LDL) particles; and (3) low high-density lipoprotein (HDL) cho-lesterol concentrations. Recent clinical trials have demonstrated the benefits of cholesterol-lowering therapy in both diabetic and nondiabetic patients, thus supporting aggressive treatment of diabetic dyslipidemia for coronary artery disease prevention. A 3-step approach is recommended for the treatment of diabetic dyslipidemia. First, modification of diet and lifestyle, including decreased intakes of cholesterol, cholesterol-raising fats, and total energy, and increased physical activity should be advised. Second, good glycemic control should be achieved with diet and hypoglycemic drugs, if needed. Third, lipid-lowering drugs should be used, if necessary. Non-HDL cholesterol levels, which include both very-low-density lipoprotein (VLDL) and LDL cholesterol, should be the target of cholesterol-lowering therapy. The use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (the "statins") has become the first-line drug therapy for diabetic dyslipidemia. Bile acid sequestrants are effective cholesterol-lowering agents in normotriglyceridemic patients with non-insulin-dependent diabetes mellitus (NIDDM). Patients with severe hypertriglyceridemia may require fibric acids or n-3 polyunsaturated fatty acids. Nicotinic acid worsens hyperglycemia; therefore, it should be avoided in most cases. The efficacy and safety of estrogen-replacement therapy in postmenopausal women with diabetes needs to be determined. The combination of two lipid-lowering agents may be appropriate for some NIDDM patients but should be used judiciously.
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PMID:Treatment of diabetic dyslipidemia. 952 14

Marked lowering of plasma total and low-density lipoprotein cholesterol levels that occur during treatment of dyslipidemia with pharmacologic doses of nicotinic acid result from hepatotoxicity. Therefore, a marked reduction in low-density lipoprotein may suggest generalized liver toxicity and drug treatment should be discontinued.
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PMID:Effects of crystalline nicotinic acid-induced hepatic dysfunction on serum low-density lipoprotein cholesterol and lecithin cholesteryl acyl transferase. 952 2

Subjects with diabetes have a greatly increased risk of CHD, which is only partially related to their elevated glucose. Other factors such as insulin resistance and dyslipidemia are likely to be important. The type of dyslipidemia that is most characteristic of type 2 diabetic subjects is elevated triglycerides and decreased HDL cholesterol levels, although all lipoproteins have compositional abnormalities. Surprisingly few good prospective studies of lipoprotein levels in relation to CHD have been done in diabetic subjects. Available studies suggest that low HDL cholesterol may be the most important risk factor for CHD in observational studies. In studies in which total cholesterol and triglyceride were done, cholesterol and triglycerides were risk factors for CHD, although triglycerides were often a stronger predictor. However, the strength of triglyceride as a risk factor for CHD may depend partially on its association with other variables (e.g., hypertension, plasminogen activator inhibitor 1 [PAI-1], etc.). In clinical trials in diabetic subjects, LDL reduction with statins has led to significant reductions in CHD incidence. In addition, overall mortality was reduced with statin therapy, although the results were not statistically significant. Gemfibrozil has led to reductions in CHD incidence in diabetic subjects, although the results were not statistically significant perhaps because of low sample size. Regarding lipoproteins and CHD risk in diabetic patients, the very positive results of statin trials point to LDL cholesterol being more important than previous realized. Apparently, having a borderline high LDL cholesterol (between 130 and 160 mg/dl) in a diabetic patient is equivalent to a much higher LDL cholesterol in terms of CHD risk for a nondiabetic subject. Therefore, the primary target of therapy in diabetic patients is lowering LDL cholesterol (or possibly, non-HDL cholesterol). Statins are the preferred pharmacological agent in this situation. Once LDL cholesterol levels have been lowered, attention can be given to treatment of residual hypertriglyceridemia and low HDL. The goal here is weight reduction and increased exercise. However, for selected patients, combining a fibric acid (or low-dose nicotinic acid) with a statin also can be considered. Reduction of LDL levels should take priority over reduction of triglycerides in combined hyperlipidemia because of the proven safety of the statin class of drugs as well as greater reduction in CHD incidence.
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PMID:Management of dyslipidemia in adults with diabetes. 953 88

The importance of treating dyslipidemias based on cardiovascular risk factors is highlighted by the National Cholesterol Education Program guidelines. The first step in evaluation is to exclude secondary causes of hyperlipidemia. Assessment of the patient's risk for coronary heart disease helps determine which treatment should be initiated and how often lipid analysis should be performed. For primary prevention of coronary heart disease, the treatment goal is to achieve a low-density lipoprotein (LDL) cholesterol level of less than 160 mg per dL (4.15 mmol per L) in patients with only one risk factor. The target LDL level in patients with two or more risk factors is 130 mg per dL (3.35 mmol per L) or less. For patients with documented coronary heart disease, the LDL cholesterol level should be reduced to less than 100 mg per dL (2.60 mmol per L). A step II diet, in which the total fat content is less than 30 percent of total calories and saturated fat is 8 to 10 percent of total calories, may help reduce LDL cholesterol levels to the target range in some patients. A high-fiber diet is also therapeutic. The most commonly used options for pharmacologic treatment of dyslipidemia include bile acid-binding resins, HMG-CoA reductase inhibitors, nicotinic acid and fibric acid derivatives. Other possibilities in selected cases are estrogen replacement therapy, plasmapheresis and even surgery in severe, refractory cases.
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PMID:Management of dyslipidemia in adults. 960 9

Hypolipidemic drugs that are efficacious in man are not always active in classical animal models of dyslipidemia. Inhibitors of HMG-CoA reductase (statins) do not lower plasma cholesterol in rats, but yet this species was alone in providing activity for fibrate-type drugs. Nicotinic acid possesses many desirable features with regard to clinical use, but most of these actions are lacking in rats and monkeys. The metabolism of low density lipoproteins in hamsters is widely thought to be similar to that in humans, yet neither statins or fibrates lower plasma lipids in these species. With the advent of mouse models expressing specific human genes (or disruption of genes) it is now possible to re-examine the effect of established drugs and to characterize new hypolipidemic compounds with respect to site and mechanism of action. Drug responses observed in humans are now being seen in such mouse models (e.g. HDL elevation with fenofibrate in mice with the human apo A-I gene). Moreover, mice are now being screened for compounds that lower plasma (human) Lp(a), or lower plasma cholesterol in the absence of LDL receptors. It is proposed that these new genetic mouse models may afford a more focused examination of drug action and provide, for new compounds, better prediction of the human response.
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PMID:Lack of predictability of classical animal models for hypolipidemic activity: a good time for mice? 973 11

Dyslipidemia in patients with diabetes constitutes quantitative and qualitative abnormalities in all classes of lipoproteins and may be a significant contributor to the high risk of atherosclerosis in these patients. A step-care approach to therapy of diabetic dyslipidemia, including hygienic measures (diet and increased physical activity), hypoglycemic drugs, and lipid-lowering drugs, is recommended. The choice of lipid-lowering drugs depends on severity of hypertriglyceridemia. Statins and bile-acid-binding resins are the choice of therapy for diabetic dyslipidemia; however, for severely hypertriglyceridemic patients, fibric acid derivatives should be used. Nicotinic acid worsens hyperglycemia and, therefore, should be avoided. The value of estrogen replacement therapy in postmenopausal women with diabetes has not been established.
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PMID:Dyslipoproteinemia and diabetes. 978 56

Usual risk factors for coronary artery disease account for only 25-50% of increased atherosclerotic risk in diabetes mellitus. Other obvious risk factors are hyperglycemia and dyslipidemia. However, hyperglycemia is a very late stage in the sequence of events from insulin resistance to frank diabetes, whereas lipoprotein abnormalities are manifested during the largely asymptomatic diabetic prodrome and contribute substantially to the increased risk of macrovascular disease. The insulin-resistant diabetes course affects virtually all lipids and lipoproteins. Chylomicron and very-low-density lipoprotein (VLDL) remnants accumulate, and triglycerides enrich high-density lipoprotein (HDL) and low-density lipoprotein (LDL), leading to high levels of potentially atherogenic particles and low levels of HDL cholesterol. Hyperglycemia eventually impairs removal of triglyceride-rich lipoproteins, the accumulation of which accentuates hypertriglyceridemia. As triglycerides increase-still within the so-called normal range-abnormalities in HDL and LDL became more apparent. Thus, when triglycerides are >200 mg/dL, LDL particles are small and dense (when they are <90 mg/dL, the particles are of the large, buoyant variety). The atherogenicity of small, dense LDL particles is attributed to their increased susceptibility to oxidation, but in many patients they may be a marker for insulin resistance or the presence of atherogenic VLDL. Hypertriglyceridemia is associated with atherosclerosis because (1) it is a marker for insulin resistance and atherogenic metabolic abnormalities; and (2) the small size of triglyceride-enriched lipoproteins enables them to infiltrate the blood vessel wall where they are oxidized, bind to receptors on macrophages, and ingested, leading to the development of the atherosclerotic lesion. Various studies (primary prevention with gemfibrozil: Helsinki Heart Study; secondary prevention with simvastatin and pravastatin: Scandinavian Simvastatin Survival Study [4S] and Cholesterol and Recurrent Events [CARE], respectively) have demonstrated that lipid-lowering therapy in type 2 diabetes is effective in decreasing the number of cardiac events. Risk reduction was 22% to 50% (statins) and approximately 65% (fibrate) relative to placebo. It was also noted (in 4S and CARE) that the risk of major coronary events in untreated diabetic patients was 1.5-1.7-fold greater than in untreated nondiabetic patients. Although gemfibrozil (fibric acid derivative) is more effective in decreasing triglycerides and increasing HDL cholesterol in diabetic patients than the statins, it does not change and may even increase LDL-cholesterol levels (fenofibrate may be an exception, decreasing LDL cholesterol by 20-25% in some studies). However, gemfibrozil does increase LDL particle size. Nevertheless, the statins are the current lipid-lowering drugs of choice because the change in LDL-cholesterol-to-HDL-cholesterol ratio is better than with gemfibrozil. Moreover, the diabetic patient may be more likely to benefit from statin therapy than the nondiabetic patient. It should be noted that, in theory, nicotinic acid can correct or improve all lipid or lipoprotein abnormalities in patients with type 2 diabetes. Unfortunately, it is relatively contraindicated because it causes insulin resistance and may precipitate or aggravate hyperglycemia (in addition to its other well-known side effects such as flushing, gastric irritation, development of hepatotoxicity, and hyperuricemia). It is unknown at present whether newer formulations such as once-daily Niaspan may be better tolerated in diabetes. In any case, most patients with type 2 diabetes have risk factors for coronary artery disease and qualify for aggressive LDL cholesterol-lowering therapy. At the same time, it is presently unknown whether improved glycemic control decreases coronary artery disease risk in such patients.
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PMID:Diabetic dyslipidemia. 991 65

Patients with type 2 diabetes (formerly known as non-insulin-resistant diabetes) have a significantly increased risk of developing cardiovascular disease. Once clinical cardiovascular disease develops, these patients have a poorer prognosis than normoglycemic patients. By inducing endothelial changes, hyperglycemia contributes directly to atherosclerosis. Type 2 diabetes is also associated with atherogenic dyslipidemias. This form of diabetes, or the precursor state of insulin resistance, commonly occurs as a metabolic syndrome (formerly known as syndrome X) consisting of hypertension, atherogenic dyslipidemia and a procoagulant state, in addition to the disorder of glucose metabolism. All cardiovascular risk factors except smoking are more prevalent in patients with type 2 diabetes. In addition to exercise, weight control, aspirin therapy and blood pressure control, therapy to modify lipid profiles is usually necessary. The choice of agent or combination of statin, bile acid sequestrant, fibric acid derivative and nicotinic acid depends on the lipid profile and characteristics of the individual patient.
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PMID:Attenuating cardiovascular risk factors in patients with type 2 diabetes. 1114 70


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