Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.1.1.34 (lipoprotein lipase)
7,025 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Associations between loss of glucose tolerance, insulin resistance, and ischemic heart disease (IHD) are of great current concern. Considerable controversy and uncertainty relates to the mechanism(s) that underlies these associations. Whilst there is some evidence in prospective studies of an association between hyperinsulinemia and future IHD, it is by no means strong or consistent between different studies. Hypertriglyceridemia is another possible factor involved in the linkage between glucose intolerance and IHD. There is good evidence for an affect of plasma nonesterified fatty acids (NEFA) to increase hepatic output of VLDL. Insulin, contrary to some suggestions, acts to lower plasma VLDL by actions directly on hepatic output and activation of adipose tissue lipoprotein lipase, and indirectly via the hormones affect of lowering plasma NEFA. Glycosylation and oxidation of lipoproteins may enhance their atherogenic potential. It is highly probable that procoagulant changes are also important processes predisposing to IHD. Associations between plasminogen activator inhibitor-1 and insulin, intact and 32,33 split proinsulin hypertriglyceridemia, and insulin resistance have been reported, but a unifying hypothesis explaining these links remains elusive. Epidemiological studies now repeated in a number of centers have shown links between infant mortality and birth weight and risk of IHD, and between birth weight and risk of impaired glucose tolerance and non-insulin-dependent diabetes mellitus (NIDDM). It has been proposed, therefore, that impairment of fetal and infant growth may underlie the associations between loss of glucose tolerance and risk of IHD. Animal models form the basis of much current research to test this concept.
...
PMID:Role of insulin and proinsulin in diabetic vascular disease. 747 16

Recent trends in antineoplastic therapy include the increasing use of cytokine-containing regimens. These widely distributed, naturally occurring substances play a pivotal role in the physiology of the neuroendocrine/immune system. It is not known to what extent the chronic administration of pharmacologic doses of exogenous cytokines may create hormonal and metabolic derangements that may, in themselves, complicate their therapeutic efficacy. This article reviews the endocrine functions of a variety of cytokines. The interferons, for example, induce insulin resistance and impaired glucose tolerance, are associated with thyroid dysfunction, and can stimulate the ACTH/cortisol axis and growth hormone. The hormonal/metabolic actions of the interleukins are being intensively studied, especially by bone metabolism, reproductive, and thyroid physiologists. Tumor necrosis factor has a profound impact on bone metabolism and remodeling, decreases lipoprotein lipase, and can affect thyroid function.
...
PMID:Endocrine effects of cytokines. 752 26

Insulin resistance with consecutive hyperinsulinemia is associated with dyslipidemia in individuals with metabolic syndrome or "syndrome x". This dyslipidemia is characterized by a hypertriglyceridemia and reduced levels of HDL-(high density lipoprotein)cholesterol in plasma. Table 1 summarizes the alterations of lipoproteins in insulin resistance. In severe forms of insulin resistance LDL-(low density lipoprotein)cholesterol can be elevated as well. The hypertriglyceridemia is caused by an elevated synthesis and secretion of VLDL (very low density lipoprotein) in the liver and by reduced metabolism, mediated e.g. by lipoprotein lipase. The alterations of VLDL-metabolism are associated with a reduced concentration of HDL-cholesterol. In addition the composition of lipoprotein particles can be altered, which might interfere with their normal metabolism. Furthermore addition direct effects of insulin on cellular cholesterol metabolism have been described. These alterations in lipid metabolism which are due to an insulin resistance and hyperinsulinemia might be related to the increased coronary risk which has been observed in patients with metabolic syndrome. Therefore the diagnostic approach in patients with hypertriglyceridemia should consider the possibility of an underlying glucose intolerance or Type 2 diabetes. Therapeutic aims and strategies are discussed. In accordance to guidelines of the American Heart Association the goals of lipid-lowering therapy take into account the prevalence of various cardiovascular risk factors in an individual patient (Table 2). Principle actions of lipid-lowering drugs on plasma lipids are outlined in Table 3. Table 4 summarizes the effect of antihypertensive drugs on plasma lipids and lipoproteins, which should be considered in the treatment of patients with dyslipidemia.
...
PMID:[Disorders of lipid metabolism in insulin resistance]. 771 75

The activity and mass of lipoprotein lipase (LPL) in postheparin plasma (PHP) from patients with hypertriglyceridemia coupled with hypertension, impaired glucose tolerance, hyperinsulinemia were investigated in order to clarify the cause of hypertriglyceridemia and the effects of bezafibrate (CAS 41859-67-0), a novel lipid lowering agent. Eight weeks of treatment with bezafibrate (200 mg/d) lowered plasma total cholesterol and triglyceride by 7 and 39%, respectively, and increased plasma high density lipoprotein (HDL) cholesterol by 23% in the patients (n = 15). The LPL activity and mass of PHP in the patients were found to be lower than in the normal controls. The LPL activity and mass of PHP in the patients before treatment with bezafibrate (n = 15) were 2.05 +/- 1.06 mumol/ml/h and 147 +/- 45 ng/ml, respectively, whereas after treatment with 200 mg/d of bezafibrate for 8 weeks, these values were 3.62 +/- 1.30 mumol/ml/h (p < 0.01) and 226 +/- 57 ng/ml (p < 0.05), respectively. The increases of LPL mass were positively correlated with the decrease of triglyceride levels during the same period. These results suggest that the expression of LPL enzyme protein is impaired in patients with hypertriglyceridemia coupled with hypertension, impaired glucose tolerance and hyperinsulinemia, and the impaired expression of LPL recovers during treatment with bezafibrate, resulting in improvement of hypertriglyceridemia.
...
PMID:Effects of treatment with bezafibrate on lipoprotein lipase activity and mass in patients with hypertriglyceridemia. 814 47

We examined the lipoprotein lipase (LPL) gene by single strand conformation polymorphism (SSCP) and by restriction fragment length polymorphism (RFLP) analysis in 106 patients with hypertriglyceridemia to screen for novel mutations and to study the contribution of LPL genetic defects in hypertriglyceridemia. We found a single incidence of a homozygous novel nonsense mutation (216G-->A; -14Tryptophan-->stop codon) in exon 1 and 6 cases heterozygous for a single transition (C-->T) at six bp upstream from splicing acceptor site of intron 3. These mutations were not found in 105 normolipidemic controls. The proband homozygous for the nonsense mutation in exon 1, a 74 year old woman, had mild hyperchylomicronemia and her post-heparin plasma showed no LPL protein. However, four heterozygous among family members did not demonstrate hypertriglyceridemia. The frequency of heterozygosity for the C-->T transition in intron 3 was significantly different from that in normolipidemic controls. Therefore, it was suggested that the mutation is involved in hypertriglyceridemia. All of the heterozygotes were men with 4 patients having impaired glucose tolerance or diabetes mellitus. These observations suggest that this polymorphism in intron 3 combined with other as yet undefined factors may be related to hypertriglyceridemia.
...
PMID:A novel nonsense mutation in exon 1 and a transition in intron 3 of the lipoprotein lipase gene. 922 35

Insulin resistance is often associated with atherosclerotic diseases in subjects with obesity and impaired glucose tolerance. This study examined the effects of insulin resistance on coronary risk factors in IRS-1 deficient mice, a nonobese animal model of insulin resistance. Blood pressure and plasma triglyceride levels were significantly higher in IRS-1 deficient mice than in normal mice. Impaired endothelium-dependent vascular relaxation was also observed in IRS-1 deficient mice. Furthermore, lipoprotein lipase activity was lower than in normal mice, suggesting impaired lipolysis to be involved in the increase in plasma triglyceride levels under insulin-resistant conditions. Thus, insulin resistance plays an important role in the clustering of coronary risk factors which may accelerate the progression of atherosclerosis in subjects with insulin resistance.
...
PMID:Hypertension, hypertriglyceridemia, and impaired endothelium-dependent vascular relaxation in mice lacking insulin receptor substrate-1. 954 10

The effect of bezafibrate on plasma lipoproteins was investigated in Japanese familial combined hyperlipidemic patients with or without an impaired glucose tolerance accompanied by a low-density lipoprotein subclass, with the major gradient gel peak at a particle diameter of less than 25.5 nm. Bezafibrate treatment at a dose of 400 mg/d for 12 weeks produced an antiatherogenic effect on lipoprotein profiles, as reflected by a decrease in plasma triglyceride levels, an increase in plasma high-density lipoprotein-cholesterol levels, induction of the large-size subclass of low-density lipoprotein, and disappearance of intermediate-density lipoproteins. The plasma total and low-density lipoprotein-cholesterol-lowering effect of bezafibrate was significant in patients without impaired glucose tolerance but was not significant in patients with impaired glucose tolerance. Bezafibrate increased lipoprotein lipase activity and decreased the activity of cholesteryl ester transfer protein, both in patients with or without impaired glucose tolerance. There was no difference in the distribution of signal peptide insertion/deletion or Xbal polymorphisms of the apolipoprotein B gene in patients with or without impaired glucose tolerance. Mechanisms other than lipoprotein lipase, cholesteryl ester transfer protein activities, and an apolipoprotein B gene polymorphism may be responsible for the resistance to lowering of plasma total and low-density lipoprotein cholesterol levels with bezafibrate treatment in familial combined hyperlipidemic patients with impaired glucose tolerance.
...
PMID:Comparison of the effect of bezafibrate on improvement of atherogenic lipoproteins in Japanese familial combined hyperlipidemic patients with or without impaired glucose tolerance. 960 27

Essential hypertension is, at least in many subjects, associated with a decrease in insulin sensitivity, whereas glycemic control is (still) normal. Metaanalyses of hypertension intervention studies revealed different efficacy of treatment on cerebral (cerebrovascular accidents [CVA]) and cardiac (coronary heart disease [CHD]) morbidity and mortality. Although CVA were reduced to an extent similar to that anticipated, the decrease in CHD was less than expected. These differences are likely to be caused by the different impact of concomitant cardiovascular risk factors, such as dyslipidemia, impaired glucose tolerance, and non-insulin-dependent diabetes mellitus on CHD and CVA. Frequently these cardiovascular risk factors are ineffectively controlled in hypertensive patients, and moreover, some of the widely used antihypertensive agents have unfavorable side effects and further deteriorate these particular metabolic risk factors. Therefore, the metabolic side effects of antihypertensive treatment have received more attention. During the past few years, studies demonstrated that most antihypertensive agents modify insulin sensitivity in parallel with alterations in the atherogenic lipid profile. Alpha1-blockers and angiotensin converting enzyme inhibitors were shown to either have no impact on or even improve insulin resistance and the profile of atherogenic lipids, whereas most of the calcium channel blockers were found to be metabolically inert. The diuretics and beta-adrenoreceptor antagonists further decrease insulin sensitivity and worsen dyslipidemia. The mechanisms by which beta-adrenoreceptor antagonist treatment exert its disadvantageous effects are not fully understood, but several possibilities exist: significant body weight gain, reduction in enzyme activities (muscle lipoprotein lipase and lecithin cholesterol acyltransferase), alterations in insulin clearance and insulin secretion, and, probably most important, reduced peripheral blood flow due to increase in total peripheral vascular resistance. Recent metabolic studies found beneficial effects of the newer vasodilating beta-blockers, such as dilevalol, carvedilol and celiprolol, on insulin sensitivity and the atherogenic risk factors. In many hypertensive patients, elevated sympathetic nerve activity and insulin resistance are a deleterious combination. Although conventional beta-blocker treatment was able to take care of the former, the latter got worse; the newer vasodilating beta-blocker generation seems to be capable of successfully treating both of them.
...
PMID:Antihypertensive therapy and insulin sensitivity: do we have to redefine the role of beta-blocking agents? 979 45

We examined the effects of the potassium channel opener KRN4884 (5-amino-N-[2-(2-chlorophenyl)ethyl]-N'-cyano-3-pyridinecarboxamidine ) on cardiovascular metabolic syndrome (i.e., syndrome X), in rats. High-fructose diet rats developed hypertension, hypertriglyceridemia, increased total cholesterol/HDL (high-density lipoprotein)-cholesterol ratio, and hyperinsulinemia, KRN4884 (0.3-3.0 mg/kg, twice a day for 14 days, p.o.) alleviated the risk factors in fructose-fed rats. Furthermore, fructose-fed rats exhibited impairment of glucose tolerance and excess insulin secretion when loaded with glucose orally. Treatment with KRN4884 (1.0 mg/kg, twice a day for 14 days, p.o.) improved the glucose intolerance and inhibited hypersecretion of insulin in the glucose-loaded, fructose-fed rats. In contrast, KRN4884 (0.3-1.0 mg/kg, twice a day for 10 days, p.o.) did not affect serum triglyceride, cholesterol, glucose, or insulin concentrations in normal rats. LPL (lipoprotein lipase) activities in skeletal muscle and adipose tissue, and HTGL (hepatic triglyceride lipase) activity in liver were measured after administration of KRN4884 or vehicle twice a day for 14 days in fructose-fed rats. KRN4884 caused a significant increase in LPL activity in muscle and tended to increase LPL activity in adipose tissue in fructose-fed rats. HTGL was decreased in fructose-fed rats as compared with normal controls and was unaffected by KRN4884. These findings suggested that KRN4884 enhances insulin sensitivity and LPL activity, which are related to glucose and lipid metabolism and may be useful for the treatment of syndrome X.
...
PMID:Effects of the K+ channel opener KRN4884 on the cardiovascular metabolic syndrome model in rats. 1067 63

HIV infection induces an early decrease of cholesterol and a late increase of triglycerides (TG) with a reduction of HDL. These changes are proportional with the lowering of CD4, which reflects the infection's severity. Both the increase of TG synthesis and the decrease of TG catabolism, in relation with a reduction of lipoprotein lipase activity, are responsible of these changes. Moreover, LDL catabolism is enhanced by macrophage scavenger receptors, due to a high proportion of small, dense LDL which are more easily oxidized. Many cytokines (interferon alpha, interleukins, TNF) play probably a pathogenic role in the dyslipidemia. Some HIV patients who received antiproteases may develop lipodystrophy with central obesity, insulino-resistance, glucose intolerance and sometimes diabetes (like in syndrome X). Other patients present a cushingoid, buffalo hump. This complication may be observed also with antiretroviral treatment other than antiproteases. The physiopathology of these findings could be in relation with structural homologies between antiproteases and some important proteins, involved in lipid and adipocyte metabolism. Cardiovascular risk linked to these perturbations is evident. The treatment is not different from the treatment for seronegative, hyperlipidemic patients: struggle against risk factors, diet advices, fibrates or statins. The antiproteases bring huge contribution to the prognosis of AIDS patients but the risk of cardiovascular complications could impair this therapeutic progress. So, it is essential to understand the pathogeny of these complications in order to discover new antiproteases, without these adverse side effects.
...
PMID:[Lipids and AIDS]. 1074 83


<< Previous 1 2 3 4 5 6 Next >>

---