Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0242339 (dyslipidemia)
 13,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dyslipidaemia may be treated with a number of safe and effective pharmacological agents that target specific lipid disorders through a variety of mechanisms. The bile-acid sequestrants--cholestyramine and colestipol--primarily decrease LDL cholesterol by binding bile acids, thereby decreasing intrahepatic cholesterol, and by increasing the activity of LDL receptors. Nicotinic acid lowers LDL cholesterol and triglyceride by decreasing VLDL synthesis and by decreasing free fatty acid mobilization from peripheral adipocytes. The HMG-CoA reductase inhibitors--fluvastatin, lovastatin, pravastatin and simvastatin--lower LDL cholesterol by partially inhibiting HMG-CoA reductase (the rate-limiting enzyme of cholesterol biosynthesis) and by increasing the activity of LDL receptors. The fibric-acid derivatives--bezafibrate, ciprofibrate, clofibrate, fenofibrate and gemfibrozil--primarily decrease triglyceride by increasing lipoprotein lipase activity and by decreasing the release of free fatty acids from peripheral adipose tissue. Probucol decreases LDL cholesterol by increasing non-receptor-mediated LDL clearance; as an anti-oxidant, probucol also decreases LDL oxidation; oxidized LDL which is thought to lead to atherogenesis. Although these agents have been proven safe in clinical trials, like any drug, they carry the risk for adverse effects. The bile-acid sequestrants may cause constipation, reflux oesophagitis, and dyspepsia, and may bind coadministered medications such as digitalis glycosides, beta blockers, warfarin, and exogenous thyroid hormone. Nicotinic acid use is commonly associated with flushing and pruritus and may also cause non-specific gastrointestinal complaints, hepatotoxicity (hepatic necrosis, hepatitis, or elevated liver enzymes), gout, myolysis, decreased glucose tolerance and increased fasting glucose levels, and ophthalmological complications including decreased visual acuity, toxic amblyopia, and cystic maculopathy. The HMG-CoA reductase inhibitors may produce liver enzyme elevations, creatine kinase elevations and rhabdomyolysis. The combination of a reductase inhibitor and a fibrate increases the risk for rhabdomyolysis. Possible adverse effects of the fibric-acid derivatives include abdominal discomfort, nausea, flatulence, increased lithogenicity of bile, liver enzyme elevations and creatine kinase elevations. Probucol may increase the QTc interval and may cause non-specific gastrointestinal complaints.
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PMID:Currently available hypolipidaemic drugs and future therapeutic developments. 859 27

Thyroid hormones influence all major metabolic pathways. Their most obvious and well-known action is an increase in basal energy expenditure obtained acting on protein, carbohydrate and lipid metabolism. With specific regard to lipid metabolism, thyroid hormones affect synthesis, mobilization and degradation of lipids, although degradation is influenced more than synthesis. The main and best-known effects on lipid metabolism include: (a) enhanced utilization of lipid substrates; (b) increase in the synthesis and mobilization of triglycerides stored in adipose tissue; (c) increase in the concentration of non-esterified fatty acids (NEFA); and (d) increase of lipoprotein-lipase activity. While severe hypothyroidism is usually associated with an increased serum concentration of total cholesterol and atherogenic lipoproteins, the occurrence of acute myocardial infarction (AMI) in hypothyroid patients is not frequent. However, hypothyroid patients appear to have an increased incidence of residual myocardial ischemia following AMI. Even in subclinical hypothyroidism, which is characterized by raised serum TSH levels with normal serum thyroid hormone concentrations, mild hyperlipidemia is present and may contribute to an increased risk of atherogenesis. Prudent substitution therapy with L-thyroxine is indicated in patients with both overt and subclinical hypothyroidism, with or without angina, to counteract the cardiovascular risk resulting from hyper-dyslipidemia.
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PMID:Thyroid and lipid metabolism. 1099 23

The composition and the transport of lipoproteins are seriously disturbed in thyroid diseases. Overt hypothyroidism is characterized by hypercholesterolaemia and a marked increase in low-density lipoproteins (LDL) and apolipoprotein B (apo A) because of a decreased fractional clearance of LDL by a reduced number of LDL receptors in the liver. The high-density lipoprotein (HDL) levels are normal or even elevated in severe hypothyroidism because of decreased activity of cholesteryl-ester transfer protein (CETP) and hepatic lipase (HL), which are enzymes regulated by thyroid hormones. The low activity of CETP, and more specifically of HL, results in reduced transport of cholesteryl esters from HDL(2) to very low-density lipoproteins (VLDL) and intermediate low-density lipoprotein (IDL), and reduced transport of HDL(2) to HDL(3). Moreover, hypothyroidism increases the oxidation of plasma cholesterol mainly because of an altered pattern of binding and to the increased levels of cholesterol, which presents a substrate for the oxidative stress. Cardiac oxygen consumption is reduced in hypothyroidism. This reduction is associated with increased peripheral resistance and reduced contractility. Hypothyroidism is often accompanied by diastolic hypertension that, in conjunction with the dyslipidemia, may promote atherosclerosis. However, thyroxine therapy, in a thyrotropin (TSH)-suppressive dose, usually leads to a considerable improvement of the lipid profile. The changes in lipoproteins are correlated with changes in free thyroxine (FT(4)) levels. Hyperthyroidism exhibits an enhanced excretion of cholesterol and an increased turnover of LDL resulting in a decrease of total and LDL cholesterol, whereas HDL are decreased or not affected. The action of thyroid hormone on Lp(a) lipoprotein is still debated, because both decrease or no changes have been reported. The discrepancies are mostly because of genetic polymorphism of apo(a) and to the differences between the various study groups. Subclinical hypothyroidism (SH) is associated with lipid disorders that are characterized by normal or slightly elevated total cholesterol levels, increased LDL, and lower HDL. Moreover, SH has been associated with endothelium dysfunction, aortic atherosclerosis, and myocardial infarction. Lipid disorders exhibit great individual variability. Nevertheless, they might be a link, although it has not been proved, between SH and atherosclerosis.
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PMID:Thyroid disease and lipids. 1203 52

Obesity and starvation have opposing affects on normal physiology and are associated with adaptive changes in hormone secretion. The effects of obesity and starvation on thyroid hormone, GH, and cortisol secretion are summarized in Table 1. Although hypothyroidism is associated with some weight gain, surveys of obese individuals show that less than 10% are hypothyroid. Discrepancies have been reported in some studies, but in untreated obesity, total and free T4, total and free T3, TSH levels, and the TSH response to TRH are normal. Some reports suggest an increase in total T3 and decrease in rT3 induced by overfeeding. Treatment of obesity with hypocaloric diets causes changes in thyroid function that resemble sick euthyroid syndrome. Changes consist of a decrease in total T4 and total and free T3 with a corresponding increase in rT3. untreated obesity is also associated with low GH levels; however, levels of IGF-1 are normal. GH-binding protein levels are increased and the GH response to GHRH is decreased. These changes are reversed by drastic weight reduction. Cortisol levels are abnormal in people with abdominal obesity who exhibit an increase in urinary free cortisol but exhibit normal or decreased serum cortisol and normal ACTH levels. These changes are explained by an increase in cortisol clearance. There is also an increased response to CRH. Treatment of obesity with very low calorie diets causes a decrease in serum cortisol explained by a decrease in cortisol-binding proteins. The increase in cortisol secretion seen in patients with abdominal obesity may contribute to the metabolic syndrome (insulin resistance, glucose intolerance, dyslipidemia, and hypertension). States of chronic starvation such as seen in anorexia nervosa are also associated with changes in thyroid hormone, GH, and cortisol secretion. There is a decrease in total and free T4 and T3, and an increase in rT3 similar to findings in sick euthyroid syndrome. The TSH response to TRH is diminished and, in severe cases, thyroid-binding protein levels are decreased. In regards to GH, there is an increase in GH secretion with a decrease in IGF-1 levels. GH responses to GHRH are increased. The [table: see text] changes in cortisol secretion in patients with anorexia nervosa resemble depression. They present with increased urinary free cortisol and serum cortisol levels but without changes in ACTH levels. In contrast to the findings observed in obesity, the ACTH response to CRH is suppressed, suggesting an increased secretion of CRH. The endocrine changes observed in obesity and starvation may complicate the diagnosis of primary endocrine diseases. The increase in cortisol secretion in obesity needs to be distinguished from Cushing's syndrome, the decrease in thyroid hormone levels in anorexia nervosa needs to be distinguished from secondary hypothyroidism, and the increase in cortisol secretion observed in anorexia nervosa requires a differential diagnosis with primary depressive disorder.
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PMID:Effect of obesity and starvation on thyroid hormone, growth hormone, and cortisol secretion. 1205 88

Dyslipidemia and obesity are common in adult patients with hypopituitarism. Possible contributions of age, sex and hormone deficiencies to hypercholesterolemia and obesity in adult hypopituitary patients were analyzed in 1, 272 Japanese cases based on a database of a national survey on adult hypopituitarism. In patients on routine hormone replacement therapy, 30.5% of male and 40.7% of female subjects were considered hypercholesterolemic. In univariate analysis, hypercholesterolemia was more prevalent in female, aged, untreated Gn-deficient and TSH-deficient groups. In multivariate analysis, sex of female, age older than 40 yr and TSH deficiency were the independent contributing factors to hypercholesterolemia. Obesity (body mass index (BMI) > or = 25 kg/m2) was more prevalent in male, TSH-deficient and ADH-deficient groups. Severe obesity (BMI > or = 30) was observed in high prevalence in the youngest group. These findings suggest that hypercholesterolemia and obesity were prevalent in different age and gender groups in Japanese adult patients with hypopituitarism. Insufficient replacement of thyroid hormone and possibly gonadotropin deficiency might contribute to hypercholesterolemia. In contrast, hypothalamic dysfunction as well as hormone deficiencies might play roles in obesity in these patients.
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PMID:Hypercholesterolemia and obesity in adult patients with hypopituitarism: a report of a nation-wide survey in Japan. 1470 49

Members of the nuclear receptor gene family act as biological rheostats to maintain metabolic homeostasis in response to endocrine and nutritional changes. The liver X (LXR) and thyroid hormone (TR) receptors have been shown to regulate overlapping but distinct metabolic pathways important for overall lipid homeostasis. Dyslipidemia is one out of four key determinants for cardiovascular risk and both LXRs and TRs may provide attractive targets for intervention of cardiovascular disease. In this review we will compare the two receptor systems to highlight similarities and differences in structure and function with implications for development of novel treatments for dyslipidemia and atherosclerosis.
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PMID:Convergence of lipid homeostasis through liver X and thyroid hormone receptors. 1554 66

Cushing's syndrome is characterized by endogenously increased production of glucocorticoids. The activity of immune system is regulated mainly by two systems in the body. Glucocorticoids and NF-kappaB counteract the effects of each other on the immune system. It has been reported that immune response is exaggerated after the amelioration of Cushing's syndrome. We report a rare case of exacerbation of Graves' disease after unilateral adrenalectomy for Cusing's syndrome. A 50-yr-obese woman with hypertension, dyslipidemia, impaired glucose tolerance and insulin resistance wasadmitted to outpatients clinic of endocrinology. The results of evaluation of glucocorticoids metabolism and adrenal magnetic resonance imaging revealed the Cusing's syndrome. We also assessed thyroid function tests because of the diagnosis of goiter and thyroid hormone replacement in her medical history, and the presence of exophthalmia and tachycardia in examination. Althoug TSH level was detected at the lower border of normal range, free T4 and free T3 were in normal range and autoantibody of thyroidal peroxidase and thyroglobulin was higer than normal reference range. An operation was performed and a mass was removed from her left adrenal gland. The pathologic examination confirmed adrenal adenoma. She was re-admitted to the outpatient clinic 9 months after with complaints of palpitation, malaise and weight loss. Tests carried out to determine the thyroid function revealed Graves' disease. We prescribed propylthiouracil and beta-blocker treatment.
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PMID:Exacerbations of Graves' disease after unilateral adrenalectomy for Cushing's syndrome. 1571 57

The nuclear oxysterol receptors, liver X receptors (LXRs), and thyroid hormone receptors (TRs) cross talk mutually in many aspects of transcription, sharing the same DNA binding site (direct repeat-4) with identical geometry and polarity. In the current study, we demonstrated that thyroid hormone (T(3)) up-regulated mouse LXR-alpha, but not LXR-beta, mRNA expression in the liver and that cholesterol administration did not affect the LXR-alpha mRNA levels. Recently, several groups have reported that human LXR-alpha autoregulates its own gene promoter through binding to the LXR response element. Therefore, we examined whether TRs regulate the mouse LXR-alpha gene promoter activity. Luciferase assays showed that TR-beta1 positively regulated the mouse LXR-alpha gene transcription. Analysis of serial deletion mutants of the promoter demonstrated that the positive regulation by TR-beta1 was not observed in the -1240/+30-bp construct. EMSA(s) demonstrated that TR-beta1 or retinoid X receptor-alpha did not bind to the region from -1300 to -1240 bp (site A), whereas chromatin-immunoprecipitation assays revealed that TR-beta1 and retinoid X receptor-alpha were recruited to the site A, indicating the presence of intermediating protein between the nuclear receptors and DNA site. We also showed that human LXR-alpha gene expression and promoter activities were up-regulated by thyroid hormone. These data suggest that LXR-alpha mRNA expression is positively regulated by TR-beta1 and thyroid hormone at the transcriptional level in mammals. This novel insight that thyroid hormone regulates LXR-alpha mRNA levels and promoter activity should shed light on a cross talk between LXR-alpha and TR-beta1 as a new therapeutic target against dyslipidemia and atherosclerosis.
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PMID:Liver X receptor-alpha gene expression is positively regulated by thyroid hormone. 1762 6

Atherosclerotic cardiovascular disease is a major problem despite the availability of drugs that influence major risk factors. New treatments are needed, and there is growing interest in therapies that may have multiple actions. Thyroid hormone modulates several cardiovascular risk factors and delays atherosclerosis progression in humans. However, use of thyroid hormone is limited by side effects, especially in the heart. To overcome this limitation, pharmacologically selective thyromimetics that mimic metabolic effects of thyroid hormone and bypass side effects are under development. In animal models, such thyromimetics have been shown to stimulate cholesterol elimination through LDL and HDL pathways and decrease body weight without eliciting side effects. We report here studies on a selective thyromimetic [KB2115; (3-[[3,5-dibromo-4-[4-hydroxy-3-(1-methylethyl)-phenoxy]-phenyl]-amino]-3-oxopropanoic acid)] in humans. In moderately overweight and hypercholesterolemic subjects KB2115 was found to be safe and well tolerated and elicited up to a 40% lowering of total and LDL cholesterol after 14 days of treatment. Bile acid synthesis was stimulated without evidence of increased cholesterol production, indicating that KB2115 induced net cholesterol excretion. KB2115 did not provoke detectable effects on the heart, suggesting that the pharmacological selectivity observed in animal models translates to humans. Thus, selective thyromimetics deserve further study as agents to treat dyslipidemia and other risk factors for atherosclerosis.
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PMID:The thyroid hormone mimetic compound KB2115 lowers plasma LDL cholesterol and stimulates bile acid synthesis without cardiac effects in humans. 1818 79

Hypolipemic agents, both statins and fibrates, may cause a spectrum of side-effects, including the transient increase in creatine phosphokinase (CPK) activity. Muscle injury may present as common myalgia, non-specific myositis with normal CPK levels, myopathy and in the most serious cases, as rhabdomyolysis. Muscle damage is much more probably in patients with concomittant kidney and liver diseases, hypothyroidism, and serious infections or after some injuries or a heavy physical effort. On the other hand, one of the most common causes of secondary hypercholesterolemia and myopathy is hypothyroidism. This condition, which may enhance the risk of muscle damage in the course of hypolipemic treatment, may sometimes present with an atypical clinical presentation, making its diagnosis challenging. In this article, we present the case of a 50-year-old male physical worker presented with marked dyslipidemia, in whom myopathy was diagnosed during therapy with hypolipemic agents. Cessation of the treatment resulted in the only moderate reduction of CPK activity. Only just the introduction of thyroid hormone supplementation led to regression of symptoms and normalization of abnormalities found in laboratory examinations including remarkable improvement in lipid profile. After several months of observation we consider that hypolipemic treatment probably revealed previously occult autoimmune thyroid disease in this patient.
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PMID:[Is every case of muscle damage during hypolipemic therapy the side effect of this therapy? A case report]. 1832 Jul 90


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