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Query: UMLS:C0020473 (hyperlipidemia)
 15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of the most prominent manifestations of the nephrotic syndrome is hyperlipidemia. Lipoprotein synthesis is increased and catabolism is reduced in nephrotic patients and animals. The observation that infusion of either albumin or dextran reduces lipid levels suggests that oncotic pressure (pi) may regulate lipogenesis. It has been postulated that prolonged plasma half-life of lipoproteins in nephrosis is a consequence of saturation of catabolic sites and is secondary to the hyperlipidemia that results from increased lipogenesis. However, the absolute rate of triglyceride catabolism is reduced in nephrotic rats in comparison to normal suggesting that defective lipid catabolism may be a cause rather than a consequence of hyperlipidemia. Furthermore, chylomicrons (CM) and very-low-density lipoproteins (VLDL) are cleared normally in rats with hereditary analbuminemia despite increased lipid synthesis. When we cause proteinuria in analbuminemic rats, the clearance of CM and VLDL becomes greatly prolonged, suggesting that proteinuria, and not reduced serum albumin or pi, is responsible for defective lipoprotein catabolism. Maneuvers that reduce proteinuria, such as administration of an angiotensin-converting enzyme inhibitor, reduce lipid levels in nephrotic patients and animals even when plasma albumin concentration is unchanged supporting a hypothesis that proteinuria may lead to reduced catabolism of lipoproteins.
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PMID:Nephrotic hyperlipidemia: primary abnormalities in both lipoprotein catabolism and synthesis. 146 61

We have recently reported that a lipid-lowering agent, probucol, reduces proteinuria in puromycin aminonucleoside (PA)-induced nephrotic rats (PAN). In this study, we examined whether a long-term treatment of hyperlipidemia with probucol can suppress the development of focal and segmental glomerulosclerosis (FSGS) in chronic PAN. A chronic PAN model was made with repeated intraperitoneal injections of PA (initially 100 mg/kg body weight followed by 25 mg/kg 5 times at 2-week intervals). Two weeks after the first injection of PA, either normal rat chow with or without 1% probucol was given to the nephrotic rats for 10 weeks. Chronic PAN exhibited remarkable proteinuria, hypoalbuminemia and severe hyperlipidemia with all lipoprotein fractions increased. Probucol treatment significantly reduced the lipid concentration in all major lipoproteins, significantly reduced proteinuria and increased plasma albumin concentration. Plasma albumin inversely correlated with cholesterol or phospholipid in low-density and high-density lipoproteins, suggesting that the lipid-lowering effect of probucol may ameliorate the hypoalbuminemia associated with nephrosis. In light microscopic examination, various degrees of FSGS with tubulointerstitial lesions were observed in the renal cortex from chronic PAN. The degree of FSGS was scored from grades 1 to 4 according to severity. One half of the untreated PAN (4/8) was classified into grade 4 and the other into grades 2 or 3, whilst one half of treated PAN (4/8) was classified either into grade 1 or 2. The grading of FSGS correlated negatively with plasma albumin concentration. These results demonstrate that probucol is highly effective upon nephrotic hyperlipidemia and suggest that a long-term treatment of secondary hyperlipidemia can suppress progressive renal injury associated with chronic nephrosis.
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PMID:Treatment of hyperlipidemia with probucol suppresses the development of focal and segmental glomerulosclerosis in chronic aminonucleoside nephrosis. 158 21

We sought to determine whether systemic administration of proteases ameliorates membranous nephritis induced in rats by immunization and challenge with cationic bovine gamma globulin, and whether targeting of protease to glomerular capillaries increases efficacy. Proteases substituted with biotin were targeted via the cationic protein avidin A, which by virtue of its charge has affinity for the glomerular basement membrane. Despite identical pretreatment proteinuria, rats given untargeted protease (biotin-conjugated without avidin, or unconjugated plus avidin) had significantly less proteinuria than saline-treated controls and nephrotic rats given avidin plus biotin-conjugated (targeted) protease had even less proteinuria and reduced glomerular rat IgG and C3. Among more severely nephrotic rats, targeted protease was again more effective than untargeted protease at reducing proteinuria, and also decreased the size of electron-dense glomerular deposits, hypercholesterolemia, and creatininemia. Inactivated targeted proteases had no effect on proteinuria, hypercholesterolemia, or azotemia. Finally, active targeted protease did not affect proteinuria in the nonimmune mediated nephrosis induced by puromycin aminonucleoside. We conclude that systemic protease can specifically diminish glomerular immune deposits, proteinuria, hyperlipidemia, and creatininemia associated with experimental immune complex glomerulonephritis but not toxic nephrosis, and that targeted protease is more effective than untargeted protease.
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PMID:Targeted enzyme therapy of experimental glomerulonephritis in rats. 170 86

Hyperlipidemia associated with nephrotic syndrome was treated with probucol and the changes in plasma lipoprotein lipid concentration and urinary protein excretion were examined in puromycin aminonucleoside-induced nephrotic rats. Rats made nephrotic exhibited severe hyperlipidemia with increases in all major lipoprotein fractions. Probucol treatment of nephrotic rats significantly lowered plasma triglyceride (TG), cholesterol (Ch) phospholipid (PL) and apoprotein B associated with very-low-density and low-density lipoprotein and Ch and PL in high-density lipoprotein (HDL). Malondialdehyde (MDA) associated with the lipoproteins was significantly elevated in nephrotic rats and probucol treatment also lowered MDA concentration in all major lipoproteins. In control rats probucol moderately, but significantly, reduced plasma TG and HDL-Ch concentrations. Proteinuria associated with nephrosis was decreased significantly by treatment with probucol. Probucol treatment did not affect blood urea nitrogen and plasma creatinine levels. A significant positive correlation existed between the amount of protein excreted in urine and the plasma lipid concentrations in all nephrotic rats, suggesting that the hypolipidemic effect of probucol may attenuate proteinuria associated with nephrosis. These results suggest that probucol may be a favorable treatment for hyperlipidemia associated with nephrotic syndrome.
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PMID:The lowering effect of probucol on plasma lipoprotein and proteinuria in puromycin aminonucleoside-induced nephrotic rats. 185 87

The present study deals with intraglomerular lipid deposition and its relation to the development of focal glomerular sclerosis (FGS) in rats. Experimental FGS was induced by repeated administration of puromycin aminonucleoside (AN) and was observed from the 3rd to 6th month. At 3 months after the beginning of the experiment, FGS lesions, marked proteinuria and hyperlipidemia were observed. Sudan III-stained sections revealed intraglomerular deposition of lipid, especially in the sclerotic lesions. An immunofluorescent study demonstrated nodular or massive deposition of IgM, IgG and fibrinogen in the sclerotic areas. Significant positive correlation was observed between the degree of intraglomerular lipid deposition and glomerular damage. In order to examine the intraglomerular lipid, isolated glomeruli which were obtained by a sieving method were analyzed by thin layer chromatography. The intraglomerular lipid consisted of cholesterol ester with a small amount of triglyceride. The incidence of sclerosis and excretion of urinary protein attained peak levels at the 3rd month and then decreased, but hyperlipidemia was prolonged. It is suggested that hyperlipidemia and intraglomerular lipid deposition may contribute to the development of FGS in aminonucleoside nephrosis.
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PMID:A study on experimental focal glomerular sclerosis in rats: significance of intraglomerular lipid deposition. 203 40

We chose to assess the role of cholesterol reduction in chronic aminonucleoside nephrosis by pharmacologically lowering serum cholesterol with cholestyramine. Two groups of rats were made nephrotic with a single intravenous dose of puromycin aminonucleoside (PA): one group (PA/resin) received 5% (w:w in diet) cholestyramine resin and the dietary control group (PA/cell) received 5% cellulose. Cholestyramine-treated rats demonstrated significant functional and histological protection. Recurrent proteinuria was significantly lower in PA/resin animals. Whole-kidney glomerular filtration rate in the PA/resin group was preserved at a level equivalent to normal age-matched control rats whereas the PA/cell group had a significantly lower value than did the normal animals. The extent of segmental glomerulosclerosis 24 wk after PA delivery was significantly lower in the PA/resin group. These results suggest a role for hyperlipidemia as one of the mechanisms involved in the pathogenesis of progressive glomerular disease.
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PMID:Cholestyramine resin ameliorates chronic aminonucleoside nephrosis. 232 67

During the past few years, the increasing speculation that the hyperlipidemia of nephrosis may be one of several pathogenic mechanisms involved in the progression of initial glomerular injury to glomerulosclerosis has generated many clinical and experimental investigations. This discussion reviews pertinent studies that address two major issues. First, the underlying pathophysiologic mechanisms involved in the development of the hyperlipidemia of nephrosis are explored. Second, this article examines recent studies that investigate how this secondary hyperlipidemia may further aggravate initial glomerular injury and contribute to a progressive glomerulopathy, primarily mediated through alterations in monocyte/macrophage function.
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PMID:Hyperlipidemia of nephrosis: pathophysiologic role in progressive glomerular disease. 248 41

In this paper, we studied the effect of elastase on aminonucleoside (AN) nephrosis which is considered a model of focal glomerular sclerosis (FGS). Elastase is an enzyme which disintegrates elastin, discovered by Balo, and used in the treatment of arteriosclerosis and hyperlipidemia. It has also been known to improve metabolism of acid mucopolysaccharides, so, this study focused on metabolic improvement. Three groups of male Sprague-Dawley rats were studied and observed at regular intervals; 30, 60, 90 days. The ANE group (AN + elastase) was administered one shot of AN (10 mg/100 g B.W.) during the test interval, while elastase (5 mg/kg B.W.) was injected 5 days/week for the entire test interval. The AN group was administered one shot of AN only. The third group was a control (C). The following results were observed: (1) Focal segmental hyalinosis and sclerosis (FSHS); ANE group was weaker than AN group. (2) Other significant qualifying glomerular changes (vacuolar change and hyaline droplets of the epithelial cells, adhesion, and foam cells); ANE group was weaker than AN group. (3) Anion loss in GBM was shown by a lack of colloidal iron staining under light microscopy, and by a lack of PEI particles under electron microscopy; there was significantly less anion loss with ANE group, than with AN group. The findings suggest that elastase has an affect on the metabolism of acid mucopolysaccharide and collagen in sclerotic lesion, and may restrain the progress of amino-nucleoside nephrosis.
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PMID:[The effect of the elastase on aminonucleoside nephrosis]. 253 42

The effects of alimentary hypercholesterolemia and nephrotic hyperlipidemia, alone and in combination, on rat peritoneal macrophage phagocytosis, basal eicosanoid production, and glomerular macrophage number during peak PA nephrosis were evaluated in rats fed four different diets: 1) normal/standard chow; 2) PA/standard chow; 3) normal/cholesterol-supplemented diet; and 4) PA/cholesterol-supplemented diet. Both PA/standard chow and normal/cholesterol-supplemented rodent groups manifested significantly greater peritoneal macrophage phagocytosis and glomerular macrophage number when compared with normal/standard chow animals. However, the combination of the nephrotic state with superimposed alimentary hypercholesterolemia (PA/cholesterol-supplemented group) produced the greatest rise in these parameters, a rise that was significantly greater than was produced in the three other groups. Regarding basal eicosanoid production by macrophages, there was a numerical trend toward increased production of thromboxane B2 in the PA/standard chow animals and normal/cholesterol-supplemented rats when compared with normal/standard chow. Again, the combination of nephrosis and alimentary hypercholesterolemia in the PA/cholesterol-supplemented group was associated with a significantly greater amount of thromboxane B2 generated when compared with the other three groups. Regarding PGE2 production, there were no significant differences among the groups, despite marked differences in fasting serum lipid levels. This data suggest that there is a synergistic effect between alimentary hypercholesterolemia and the secondary hyperlipidemia of nephrosis in producing these macrophage functional alterations. Because fasting triglyceride values between the two nephrotic groups were indifferent, one can further speculate that it is the elevation of the serum cholesterol value that predominantly evokes these changes in macrophage function.
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PMID:Altered functional characteristics of rat macrophages during nephrosis. Synergistic effects of hypercholesterolemia. 280 85

The glomerulus is a complex structure containing a remarkable capillary bed which is freely permeable to water and solutes up to the size of inulin. Many small proteins are filtered, reabsorbed, and catabolized by the kidney; but most large proteins, such as albumin or immunoglobulins, are almost entirely excluded from the glomerular ultrafiltrate due to the charge-size permselectivity of the glomerular capillary basement membrane. These large proteins appear in the urine when diseases reduce the charge selectivity or result in the development of large pores in this membrane. The reabsorptive capacity of the renal tubules for these proteins is overwhelmed. Hypoalbuminemia results when increased synthetic and decreased catabolic rates of albumin fail to compensate for the urinary loss of the protein. The resulting decrease in serum oncotic pressure increases the flux of fluid out of systemic capillaries into the interstitial space, a process that increases lymphatic flow and returns the relatively protein-poor ultrafiltrate to the plasma compartment. Interstitial proteins are swept into the plasma by the increased lymphatic flow, leading to a depletion of the extravascular pool of albumin even more severe than the depletion of albumin in the plasma compartment. The rate of albumin synthesis is increased but not sufficiently to replace losses and restore the serum concentration to normal. The rate of albumin catabolism is decreased. This decrease from the normal catabolic rate is as important as the increased rate of albumin synthesis in maintenance of albumin homeostasis in nephrosis. Whereas the reduced serum oncotic pressure certainly contributes to edema formation, sodium retention may result from processes intrinsic to the kidney itself; and plasma volume may actually be expanded despite hypoalbuminemia. The hyperlipemia that occurs in nephrosis is due to a combined defect in lipoprotein metabolism: increased hepatic synthesis of VLDL and decreased removal of TG and highly atherogenic remnants of incompletely metabolized CMs. The defects in lipoprotein metabolism may in part be the end result of the urinary loss of highly negative-charged macromolecules of the mucopolysaccharide called orosomucoid, which carries with it heparan sulfate, and important cofactor for LPL.
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PMID:Mechanisms and consequences of proteinuria. 351 85


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