Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020473 (hyperlipidemia)
 15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The peroxisome proliferator-activated receptors (PPARs) are a family of fatty acid-activated transcription factors which control lipid homeostasis and cellular differentiation. PPARalpha (NR1C1) controls lipid oxidation and clearance in hepatocytes and PPARgamma (NR1C3) promotes preadipocyte differentiation and lipogenesis. Drugs that activate PPARalpha are effective in lowering plasma levels of lipids and have been used in the management of hyperlipidemia. PPARgamma agonists increase insulin sensitivity and are used in the management of type 2 diabetes. In contrast, there are no marketed drugs that selectively target PPARdelta (NR1C2) and the physiological roles of PPARdelta are unclear. In this report we demonstrate that the expression of PPARdelta is increased during the differentiation of human macrophages in vitro. In addition, a highly selective agonist of PPARdelta (compound F) promotes lipid accumulation in primary human macrophages and in macrophages derived from the human monocytic cell line, THP-1. Compound F increases the expression of genes involved in lipid uptake and storage such as the class A and B scavenger receptors (SRA, CD36) and adipophilin. PPARdelta activation also represses key genes involved in lipid metabolism and efflux, i.e. cholesterol 27-hydroxylase and apolipoprotein E. We have generated THP-1 sublines that overexpress PPARdelta and have confirmed that PPARdelta is a powerful promoter of macrophage lipid accumulation. These data suggest that PPARdelta may play a role in the pathology of diseases associated with lipid-filled macrophages, such as atherosclerosis, arthritis, and neurodegeneration.
 ...
PMID:The peroxisome proliferator-activated receptor delta promotes lipid accumulation in human macrophages. 1155 74

The scope of this review is to discuss the new advances in our understanding of the role of scavenger receptor class A in the initiation and modulation of the atherosclerotic process. Through the approaches of gene manipulation in the mouse model, a substantial body of literature has accumulated that depicts scavenger receptor class A as a central player in atherogenesis. In studies of scavenger receptor class A overexpression in macrophages through bone marrow transplantation using transgenic donor material, recipient mice with hyperlipidemia caused either by apolipoprotein E or LDL receptor deficiency did not show convincing changes in the degree of atherosclerosis development compared with controls. Conversely, the deletion of the scavenger receptor class A gene in the mouse has shown, in a consistent and significant fashion, that this receptor serves a pro-atherogenic function under hyperlipidemic conditions, as both apolipoprotein E and LDL receptor-deficient mice had reduced atherosclerosis in the absence of scavenger receptor class A. In addition, we have recently shown that C57BL/6 mice are protected from diet-induced atherosclerosis when they lack scavenger receptor class A, and that the macrophage is the cell type responsible for the effect of scavenger receptor class A deficiency in reducing lesion formation in C57BL/6 and LDL receptor null mice. Together, these results demonstrate that macrophage scavenger receptor class A contributes significantly to atherosclerotic lesion formation, and suggest that the uptake of oxidized or modified lipoproteins by vessel wall macrophages is a central process in atherogenesis.
 ...
PMID:Class A scavenger receptors, macrophages, and atherosclerosis. 1156 Nov 67

Mesangial expansion is a key feature in the pathogenesis of numerous renal diseases involving the glomerulus. Studies indicate that mutations in apolipoprotein E (apoE) might independently contribute to kidney dysfunction. Although the role of apoE as an atheroprotective molecule is well established, its role in kidney is unclear. In this study, we sought to explore whether apoE has a protective function in kidney. Northern blotting and reverse transcriptase-polymerase chain reaction showed apoE expression in kidney, and mesangial cell is a major source of apoE in kidney. In the kidneys of 14-16-month-old apoE-null mice, hematoxylin-eosin (HE) staining revealed increased mesangial cell proliferation and matrix formation compared with wild type mice or apoB-overexpressing mice, which have elevated plasma cholesterol and triglycerides. These data suggest that lack of apoE, rather than hyperlipidemia, contributes to increased mesangial expansion. We isolated mesangial cells from mouse kidney and determined the effect of apoE on cell growth. ApoE (E3, 10 microg/ml) completely inhibited serum, platelet-derived growth factor (10 ng/ml), as well as low density lipoprotein-induced mesangial cell proliferation. Among the three isoforms, E3 was found to be most effective in inhibiting mesangial cell proliferation. ApoE did not show any cytotoxic effect, and moreover, inhibited mesangial cell apoptosis induced by oxidized low density lipoprotein. These data suggest that apoE regulates growth as well as survival of mesangial cells. We previously showed that apoE induces matrix heparan sulfate proteoglycan (HSPG) in vascular cells, which has an antiproliferative effect. Similarly, apoE induced the mesangial matrix HSPG. Perlecan is the major HSPG of mesangial matrix and subendothelial space, and consistent with this, blockade of perlecan reversed the antiproliferative effect of apoE. Immunohistochemistry revealed reduced staining of perlecan in kidney from apoE-null mice. Because the loss of anionic HSPG in the basement membrane and mesangial matrix is associated with disruption of filtration barrier, these data suggest a novel role for kidney apoE in preserving the filtration barrier. In summary, apoE has a protective function in kidney as an autocrine regulator of mesangial expansion and kidney function.
 ...
PMID:A protective role for kidney apolipoprotein E. Regulation of mesangial cell proliferation and matrix expansion. 1157 84

Lipoprotein glomerulopathy (LPG) is a newly recognized renal disease characterized by thrombus-like lipoproteins in the glomerular capillaries and abnormal lipoprotein profiles similar to those in type III hyperlipoproteinemia. Recently, these conditions have been shown to be associated with some apolipoprotein E (apoE) mutations. We found an apoE mutation (designated apoE-Sendai) that substitutes arginine 145 with proline. This mutation occurs most frequently in Japanese patients with LPG. To elucidate the etiological role of this mutation in the apoE gene, we established an experimental model for LPG by transducing apoE-Sendai in apoE knockout mice with the use of an adenovirus vector. Based on the findings in patients with LPG and its animal model, we suggest that the glomerular lesions are not only caused by hyperlipidemia, but also by in situ interaction between lipoprotein-containing mutant apoE with the glomerulus. In this review, we outline the clinical features of LPG and discuss the relationship between apoE mutations and LPG.
 ...
PMID:Etiological significance of apolipoprotein E mutations in lipoprotein glomerulopathy. 1185 53

In this study, we investigated the role of T and B lymphocytes in neointimal hyperplasia after endothelial denudation. Catheter-induced endothelial denudation of wild-type mice resulted in rapid infiltration of lymphocytes to the site of injury. Mice defective in recombination-activating gene 2 (RAG2(-/-)) showed increased neointimal formation 14 days after vascular injury in comparison to their wild-type immune-competent littermates. Immunohistochemical studies revealed the preponderance of smooth muscle cells and a significantly higher number of proliferating cells in the neointima of the RAG2(-/-) mice. The neointima size and the number of proliferating smooth muscle cells in the injured vessel of RAG2(-/-) mice were similar to those observed in the injured arteries of apolipoprotein E (apoE)-deficient (apoE(-/-)) mice. Interestingly, mice with double apoE and RAG2 gene mutations (apoE(-/-) RAG2(-/-)) displayed similar neointimal characteristics as mice with a single gene defect, suggesting a similar mechanism for apoE and lymphocyte protection against injury-induced neointimal formation. The protective role of lymphocytes against neointimal formation after vascular injury directly contrasts to their reported role in the promotion of atherosclerosis, which was observed in both apoE(+/+) and apoE(-/-) mice. Thus, these results support the hypothesis of different etiology between hyperlipidemia-induced atherosclerosis and injury-induced vascular occlusion.
 ...
PMID:Both apolipoprotein E and immune deficiency exacerbate neointimal hyperplasia after vascular injury in mice. 1188 89

Low density lipoprotein receptor deficient (LDLR-KO) and apolipoprotein E deficient (apo E-KO) mice both develop hyperlipidemia and atherosclerosis by different mechanisms. The aim of the present study was to compare the effects of simvastatin on cholesterol levels, endothelial dysfunction, and aortic lesions in these two models of experimental atherosclerosis. Male LDLR-KO mice fed a high cholesterol (HC; 1%) diet developed atherosclerosis at 8 months of age with hypercholesterolemia. The addition of simvastatin (300 mg/kg daily) to the HC diet for 2 more months lowered total cholesterol levels by approximately 57% and reduced aortic plaque area by approximately 15% compared with the LDLR-KO mice continued on HC diet alone, P<0.05. Simvastatin treatment also improved acetylcholine (ACh)-induced endothelium-dependent vasorelaxation in isolated aortic rings, which was associated with an increase in NOS-3 expression by approximately 88% in the aorta measured by real time polymerase chain reaction (PCR), P<0.05. In contrast, in age-matched male apo E-KO mice fed a normal diet, the same treatment of simvastatin elevated serum total cholesterol by approximately 35%, increased aortic plaque area by approximately 15%, and had no effect on endothelial function. These results suggest that the therapeutic effects of simvastatin may depend on the presence of a functional apolipoprotein E.
 ...
PMID:Anti-atherosclerotic effect of simvastatin depends on the presence of apolipoprotein E. 1194 94

Hyperlipidemia is now established as a major risk factor for causation of coronary heart disease (CHD) in adults; however, there is much debate on the level of coronary risk at which lipid-lowering drugs should be used. These issues of possible harm or lack of benefit from long-term use of lipid-lowering therapy, and cost effectiveness, are also pertinent in the pediatric setting. Evidence from several countries indicates that children have an increasing prevalence of obesity, hyperlipidemia and type 2 diabetes mellitus. Children who have high serum lipids 'track' these increased levels into adulthood. In some countries there is a trend to screen children for hypercholesterolemia. Family history itself is a poor discriminator in determining which children need to be screened and treated. Estimation of apolipoprotein B and/or apolipoprotein E genotype can improve prediction. Measuring high density lipoprotein cholesterol also helps, but obesity appears to be the best marker for screening children at high risk. These considerations should not cloud the need for case finding and treatment of children with genetic disorders. Low fat diets have been shown to be well tolerated and effective in children; however, there are no major long-term studies demonstrating harm or benefit in those on lipid-lowering drugs. Nevertheless, concerns regarding the psychological effect and the theoretical metabolic effects of long-term lipid lowering remain. Lipid-lowering drugs should be generally restricted to children with genetic disorders of lipid metabolism. Children with diabetes mellitus, hypertension or nonlipid-related inherited disorders leading to premature CHD in adults should be treated with diet, and with lipid-lowering drugs when they reach adulthood. Children with secondary hyperlipidemia should be assessed individually. A number of drugs and nutriceuticals are available for use in children, but only a few drugs are licensed for use in children.
 ...
PMID:Should pediatric patients with hyperlipidemia receive drug therapy? 1196 May 11

The prevalance of hyperlipidemia in chronic renal failure (CRF) patients is higher than in general population. Secondary amyloidosis is a common cause of CRF in Turkey. In this study, 25 patients with CRF due to secondary renal amyloidosis (amyloid-CRF), 15 patients with CRF without amyloidosis-CRF and 17 healthy controls were studied for serum lipid parameters. The mean serum lipoprotein (a) [LP(a)] level in the patients with amyloid-CRF was significantly higher than in the controls (p < 0.01). The mean serum apolipoprotein B (Apo B), apolipoprotein E (Apo E) and triglyceride levels in the patients with amyloid-CRF were very significantly higher than in the controls (p < 0.001). The mean serum total cholesterol, low-density lipoprotein (LDL) levels in the patients with amyloid-CRF were higher than in the controls (p < 0.05). The mean serum apo AI levels in the patients with amyloid-CRF was very significantly lower than in the controls (p < 0.001). The mean serum high-density lipoprotein (HDL) in the patients with amyloid-CRF was lower than in the controls (p < 0.05). The mean serum Lp (a), Apo AI, Apo B and Apo E levels in the patients with amyloid-CRF were significantly higher than in the patients with CRF (p < 0.01). The mean serum total cholesterol, trigliserides, LDL and HDL levels in the patients with amyloid-CRF were higher than in the patients with CRF (p < 0.05). There was not any correlation with serum lipid parameters and serum albumin and urine protein levels (p > 0.05). Our study suggests that serum lipid parameters are abnormal and might be the risk factor of atherosclerotic vascular disease and contribute to renal disease progression in the patients with secondary renal amyloidosis and lipid abnormalities were different from CRF with various etiology, without amyloidosis.
 ...
PMID:Lipoprotein abnormalities in patients with secondary renal amyloidosis. 1198 51

Hyperlipidemia, smoking, and obesity are well-known risk factors for cardiovascular disease. Conversely, moderate alcohol intake is associated with lower atherosclerosis risk. However, the influence of taking alcohol on the interrelationships of these factors in a particular context has not been thoroughly investigated. In this study, we asked whether the association between plasma measures of lipid metabolism and alcohol intake is dependent on context defined by gender, age, body mass index (BMI), smoking, and apolipoprotein E (APOE) genotype. Data were obtained in a sample of 869 women and 824 men who participated in the Quebec Heart Health Survey. There was no evidence that variation among APOE genotypes influenced the association between LDL cholesterol (LDL-C) or HDL cholesterol (HDL)-C and alcohol, after adjustment for age and BMI. Further, the positive (LDL-C and BMI) and the negative (HDL-C and BMI) associations that were observed in men and women with the epsilon3/2 and epsilon3/3 genotypes were not modified by alcohol intake. However, in women with the epsilon4/3 genotype only, we found a significant influence of an alcohol by BMI interaction on the prediction of total cholesterol, LDL-C, HDL-C, apoA-I, and apoB, and this interaction was influenced by the status of smoking. Whereas the influence of an alcohol by BMI interaction on total cholesterol and LDL-C was significant in smokers, its influence on HDL-C was significant only in non-smokers. This study emphasizes the context dependency of the influence of alcohol on lipid metabolism and demonstrates how biological, environmental, and genetic factors interact to determine cardiovascular disease risk.
 ...
PMID:Impact of alcohol intake on measures of lipid metabolism depends on context defined by gender, body mass index, cigarette smoking, and apolipoprotein E genotype. 1200 97

Abdominal aortic aneurysms (AAA) have a high prevalence in aged populations and are responsible for a large number of deaths. Despite the widespread nature of the disease, relatively little is known regarding mechanisms for formation and progression of aortic aneurysms. In part, this lack of knowledge is attributable to a paucity of animal models for this disease. This review summarizes the available animal models of AAA and focuses on a novel model of reproducible AAA generated by infusion of angiotensin II (AngII) into mice rendered hyperlipidemic by the absence of either apolipoprotein E or low-density lipoprotein receptors. AAA generated by AngII infusion have many characteristics of the human disease including marked luminal expansions, perimedial remodeling, inflammation, thrombosis and a link to hyperlipidemia. As in the human disease, male mice are more susceptible to the development of AAA than females. The vascular pathology occurs from the effects of AngII at AT1 receptors present on bone marrow-derived cells. Studies are ongoing to define the mediators responsible for AngII-induced inflammation and degradation of the medial layer of the vascular wall. The AngII-induced model of AAA has the potential to provide novel insights into the underlying mechanisms of this disease and assist with the development of pharmacological therapies.
 ...
PMID:Abdominal aortic aneurysms: fresh insights from a novel animal model of the disease. 1208 34


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>