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)

Absent hepatic lipase (HL) activity results in dyslipidemia and premature atherosclerosis. DNA sequencing of the HL gene from subjects with heritable HL deficiency identified a new C to T substitution within exon 8 that in the mature enzyme caused a threonine to methionine change at position 383 (T383M). With a rapid DNA detection method we observed that all 6 individuals with complete HL deficiency from 2 families had the T383M mutation. None of 50 random unrelated unaffected subjects had this mutation. We propose that T383M is specific to families with heritable HL deficiency. Furthermore, structural variation at the HL gene, possibly in combination with other factors, appears to be etiologic in HL deficiency.
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PMID:A hepatic lipase gene mutation associated with heritable lipolytic deficiency. 167 86

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

Adipose tissue lipoprotein lipase (LPL) activity is decreased in patients with poorly controlled diabetes, and this contributes to the dyslipidemia of diabetes. To study the mechanism of this decrease in LPL, we studied adipose tissue LPL expression in male rats with streptozotocin-induced diabetes. Heparin releasable and extractable LPL activity in the epididymal fat decreased by 75-80% in the diabetic group and treatment of the rats with insulin prior to sacrifice reversed this effect. Northern blot analysis indicated no corresponding change in LPL mRNA levels. However, LPL synthetic rate, measured using [(35)S]methionine pulse labeling, was decreased by 75% in the diabetic adipocytes, and insulin treatment reversed this effect. These results suggested regulation of LPL at the level of translation. Diabetic adipocytes demonstrated no change in the distribution of LPL mRNA associated with polysomes, suggesting no inhibition of translation initiation. Addition of cytoplasmic extracts from control and diabetic adipocytes to a reticulocyte lysate system demonstrated the inhibition of LPL translation in vitro. Using different LPL mRNA transcripts in this in vitro translation assay, we found that the 3'-untranslated region (UTR) of the LPL mRNA was important in controlling translation inhibition by the cytoplasmic extracts. To identify the specific region involved, gel shift analysis was performed. A specific shift in mobility was observed when diabetic cytoplasmic extract was added to a transcript containing nucleotides 1818-2000 of the LPL 3'-UTR. Thus, inhibition of translation is the predominant mechanism for the decreased adipose tissue LPL in this insulin-deficient model of diabetes. Translation inhibition involves the interaction of a cytoplasmic factor, probably an RNA-binding protein, with specific sequences of the LPL 3'-UTR.
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PMID:The translational regulation of lipoprotein lipase in diabetic rats involves the 3'-untranslated region of the lipoprotein lipase mRNA. 1102 42

It has recently been proposed that primary mutations in genes involved in fatty acid and lipid metabolism may contribute to the pathogenesis of insulin resistance and dyslipidemia often observed in spontaneous forms of hypertension. In the current study in the spontaneously hypertensive rat (SHR), we mapped and sequenced the gene encoding a key transcription factor known as ADD1 (adipocyte determination and differentiation factor 1) or SREBP-1c (sterol regulatory element binding protein- c) that has recently been identified as a master regulator of genes involved in the hepatic control of lipid and carbohydrate metabolism. We found that (1) the gene for ADD1/SREBP-1c maps to a region of rat Chromosome 10 previously reported to contain a quantitative trait locus involved in the regulation of hepatic cholesterol levels and (2) the SHR harbors a valine-to-methionine substitution in the COOH terminal portion of the ADD1/SREBP-1 protein that is not present in 44 other strains of laboratory rats. These findings, together with previous studies showing that transgenic expression of SREBP-1 isoforms has major effects on hepatic fatty acid and cholesterol biosynthesis, suggest that naturally occurring variation in the gene encoding the SREBP-1 isoforms might contribute to inherited variation in lipid metabolism in the SHR versus other strains of rats. These results should serve to motivate future transfection studies of the effect of the SHR mutant on SREBP-1 expression and activation in vitro, as well as the development of congenic and transgenic strains of SHR to investigate the effects of different variants of SREBP-1 on carbohydrate and lipid metabolism in vivo.
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PMID:Identification of a mutation in ADD1/SREBP-1 in the spontaneously hypertensive rat. 1130 61

Betaine is distributed widely in animals, plants, and microorganisms, and rich dietary sources include seafood, especially marine invertebrates ( approximately 1%); wheat germ or bran ( approximately 1%); and spinach ( approximately 0.7%). The principal physiologic role of betaine is as an osmolyte and methyl donor (transmethylation). As an osmolyte, betaine protects cells, proteins, and enzymes from environmental stress (eg, low water, high salinity, or extreme temperature). As a methyl donor, betaine participates in the methionine cycle-primarily in the human liver and kidneys. Inadequate dietary intake of methyl groups leads to hypomethylation in many important pathways, including 1) disturbed hepatic protein (methionine) metabolism as determined by elevated plasma homocysteine concentrations and decreased S-adenosylmethionine concentrations, and 2) inadequate hepatic fat metabolism, which leads to steatosis (fatty accumulation) and subsequent plasma dyslipidemia. This alteration in liver metabolism may contribute to various diseases, including coronary, cerebral, hepatic, and vascular diseases. Betaine has been shown to protect internal organs, improve vascular risk factors, and enhance performance. Databases of betaine content in food are being developed for correlation with population health studies. The growing body of evidence shows that betaine is an important nutrient for the prevention of chronic disease.
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PMID:Betaine in human nutrition. 1532 91

Polycystic ovary syndrome (PCOS) is a variable disorder that is characterized in adolescents and young women by a broad spectrum of anomalies, including hyperandrogenemia, insulin resistance, dyslipidemia, body adiposity and low-grade inflammation. At present, there is no approved therapy for PCOS. Recent studies indicate that a low-dose combination of flutamide (Flu; a generic androgen-receptor blocker) and metformin (Met; a generic insulin-sensitizer) normalizes the adolescent PCOS spectrum more than an oral contraceptive (OC); in young women, the PCOS spectrum was found to be more normalized by OC plus Flu-Met than by OC alone. Within the pathophysiological cascade of PCOS, Flu-Met seems to counter upstream anomalies like hyperinsulinemia or hyperandrogenism, thereby preventing or reversing downstream effects. In contrast, an OC essentially masks downstream symptoms like hirsutism, acne or irregular menses, whereas the upstream aberrations remain unaltered or may even be worsened. The available experience with Flu-Met is limited but promising. We emphasize that Flu-Met may (as part of its efficacy) induce ovulation but is contra-indicated post-conception because of potential embryotoxicity; therefore, it seems wise to combine Flu-Met with an oral or a transdermal oestro-progestagen or with a non-endocrine method of contraception. May this update prompt further research into Flu-Met's therapeutic potential in patients with PCOS. Until the abovementioned effects have been broadly confirmed, Flu-Met should not be regarded as a standard therapy for widespread clinical practice.
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PMID:Low-dose flutamide-metformin therapy for hyperinsulinemic hyperandrogenism in non-obese adolescents and women. 1640 52

Metabolic disturbances such as dyslipidemia, lipodystrophy syndrome, visceral obesity, hyperlactatemia, diabetes mellitus, and hepatic steatosis have been recognized as serious complications in long-term antiretroviral-treated HIV-infected patients. The oxidative capacity of liver mitochondria plays a central role in their pathogenesis and can be analyzed using the [(13)C]methionine breath test. We analyzed hepatic mitochondrial function using the [(13)C]methionine breath test in antiretrovirally treated and untreated HIV-infected patients as well as HIV-negative controls. Patients with hepatic steatosis, hypertriglyceridemia, lipohypertrophy, and older age showed reduced methionine metabolism. Hepatic mitochondrial function is impaired in antiretroviral-treated HIV-infected patients with disturbances of lipid metabolism.
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PMID:[(13)C]Methionine breath test as a marker for hepatic mitochondrial function in HIV-infected patients. 2000 11

Retinal vein occlusion (RVO) is a disease that is often associated with a variety of systemic disorders including arterial hypertension, diabetes mellitus, dyslipidemia and systemic vasculitis. There are various types of RVO, categorized on the basis of the site of occlusion and on the type of consequent vascular damage. Central retinal vein occlusion (CRVO) is the most clinically relevant type of RVO. In addition to well-known classical risk factors, new thrombophilic factors have been investigated in patients with RVO. Data concerning a number of the parameters remain contradictory; yet, hyperhomocysteinemia and vitamins involved in methionine metabolism appear to play a significant role in the pathogenesis of this disease. Alterations in the fibrinolysis pathway (elevated levels of PAI-1 and Lipoprotein (a)), together with haemorheologic modifications have been recently consistently associated with the disease. Medical treatment includes identification and correction of vascular risk factors. In addition, LMWHs appear to be the best therapeutic approach even if based on a limited number of trials, conducted on a limited number of patients. No data are available on the possible role of antithrombotic strategies in the long-term prevention of recurrent RVO or vascular events.
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PMID:Retinal vein occlusions: a review for the internist. 2159 Apr 40

Homocysteine, a sulfur-containing amino acid formed during the metabolism of methionine, exert cytotoxic effects on vascular endothelium. Molecular mechanisms of homocysteine-induced cellular dysfunction include increased inflammatory cytokine expression, altered nitric oxide bioavailability, induction of oxidative stress, activation of apoptosis and defective methylation. Hyperhomocysteinemia is associated with an increased risk of atherosclerotic and thromboembolic disorders, as well as hyperinsulinemia and may partially account for increased risk of cardiovascular disease associated with insulin resistance. Women with PCOS are more likely to develop components of the metabolic syndrome such as disturbances of carbohydrate metabolism, obesity, hypertension and dyslipidemia, which in turn are risk factors for cardiovascular disease. A number of studies confirmed the presence of increased serum homocysteine concentration in PCOS patients and the possible determinants of this observation are still debated. PCOS treatment options can influence homocysteine levels.
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PMID:Homocysteine metabolism in polycystic ovary syndrome. 2179 5

Women with type 2 diabetes mellitus (T2DM) are at a greater risk of developing and dying from breast cancer than women without T2DM. Insulin resistance and hyperinsulinemia underlie the pathogenesis of T2DM. In the MKR mouse model of insulin resistance, we have previously shown increased activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR pathway in association with accelerated mammary tumor growth. In this study, we demonstrate that inhibiting PI3K with the oral pan-class I PI3K inhibitor, NVP-BKM120 reduced the growth of Met-1 and MCNeuA mammary tumor orthografts in the MKR mouse. NVP-BKM120 treatment decreased phosphorylation of Akt and S6 ribosomal protein (S6rp); no change in Erk1/2 phosphorylation was seen. Hyperglycemia, hypertriglyceridemia and greater hyperinsulinemia developed in the MKR mice treated with NVP-BKM120. We previously reported reduced tumor growth using intraperitoneal rapamycin in the MKR mouse, with the development of hyperglycemia and hypertriglyceridemia. Therefore, we examined whether the oral PI3K/mTOR inhibitor NVP-BEZ235 augmented the tumor suppressing effects of PI3K inhibition. We also investigated the effect of targeted PI3K/mTOR inhibition on PI3K/Akt/mTOR and Erk1/2 signaling, and the potential effects on glycemia. NVP-BEZ235 suppressed the growth of Met-1 and MCNeuA tumor orthografts, and decreased Akt and S6rp phosphorylation, despite increased Erk1/2 phosphorylation in Met-1 orthografts of MKR mice. Less marked hyperglycemia and hyperinsulinemia developed with NVP-BEZ235 than NVP-BKM120. Overall, the results of this study demonstrated that inhibiting PI3K/Akt/mTOR signaling with the oral agents NVP-BKM120 and NVP-BEZ235 decreased mammary tumor growth in the hyperinsulinemic MKR mouse. Inhibiting PI3K alone led to more severe metabolic derangement than inhibiting both PI3K and mTOR. Therefore, PI3K may be an important target for the treatment of breast cancer in women with insulin resistance. Monitoring for hyperglycemia and dyslipidemia should be considered when using these agents in humans, given the metabolic changes detected in this study.
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PMID:Inhibiting PI3K reduces mammary tumor growth and induces hyperglycemia in a mouse model of insulin resistance and hyperinsulinemia. 2203 15


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