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PubMed1999

Modification of lipoprotein lipase catalytic activity by sialic acids.

The role of sialic acid linked with lipoprotein lipase (LPL) in its catalytic activity was studied. When LPL was treated with sialidase, the molecular weight decreased by 2000. The sialidase-treated LPL showed unchanged hydrolyzing activity for tributyrin, a water-soluble substrate of esterase, compared with the untreated LPL. The sialidase-treated LPL also showed similar hydrolyzing activity for triolein emulsified with Triton X-100, phosphatidylcholine and phosphatidylethanolamine, whereas it showed significantly increased hydrolyzing activity for triolein emulsified with phosphatidylserine and cardiolipin (152% and 183%, compared with untreated LPL, respectively). In addition, the sialidase-treated LPL showed significantly increased hydrolyzing activity against triolein incorporated into very low-density lipoproteins and chylomicrons (151% and 186%, compared with the untreated LPL, respectively). These results suggest that the loss of sialic acids does not modify the function of the catalytic site of LPL, but facilitates the interaction of the enzyme with the interface of the surface of substrate lipoproteins.

Animals↗
PubMed2002

Lipoprotein lipase from rainbow trout differs in several respects from the enzyme in mammals.

Previously we found lipase activity with characteristics similar to lipoprotein lipase (LPL) in tissues from rainbow trout [Biochim. Biophys. Acta 1255 (1995) 205], whereas no equivalent to the related hepatic lipase could be found. An equivalent to apolipoprotein CII was also identified and characterized [Gene 254 (2000) 189]. We present here the full nucleotide sequence for LPL from rainbow trout (Oncorhynchus mykiss) and have investigated some properties of the enzyme. In contrast to what has been found in mammals, LPL mRNA was expressed in livers of adult trout. This indicates that trout LPL carries out functions that hepatic lipase has evolved to take over in mammals. Trout LPL was unstable at 37 degrees C compared with bovine and human LPL. Two sequence differences that may relate to the instability are that trout LPL lacks the disulfide bridge in the C-terminal domain and lacks Pro(258). This residue is conserved in LPL from all mammals and has been shown to be critical for enzyme stability at 37 degrees C. On chromatography on heparin-Sepharose trout and chicken LPL eluted at higher salt concentration than bovine (or other mammalian) LPL. The C-terminal end of LPL has been implied in heparin binding and the higher heparin affinity of the trout and chicken enzymes may be because they have 17 and 15 extra amino acid residues at the C-terminal end, of which three residues are positively charged.

Adipose Tissue↗
PubMed2002

[Effect of propylene glycol mannate sulfate on blood lipids and lipoprotein lipase in hyperlipidemic rat].

AIM: To study the effect of propylene glycol mannate sulfate (PGMS) on blood lipids and lipoprotein lipase in hyperlipidemic rat, and its anti-hyperlipidemic mechanism. METHODS: PGMS was administered ig at different doses (37.8 mg.kg-1.d-1 and 75.6 mg.kg-1.d-1) to hyperlipidemic rats for three weeks and blood serum was obtained after starved 12 h. Total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) were examined. The mRNA expression of lipoprotein lipase (LPL) in liver, spleen and artery was detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: PGMS significantly decreased the levels of TC, TG and LDL-C and increased that of HDL-C in hyperlipidemic serum dose-dependently. PGMS was shown to increase the level of LPL mRNA expression, which is related directly to the controlling effects of PGMS on blood lipids. CONCLUSION: PGMS modulated blood lipids by promoting mRNA expression of LPL. This may be one important mechanism of PGMS to modulate blood lipids.

Animals↗
PubMed1999

Acquired lipoprotein lipase deficiency associated with chronic urticaria. A new etiology for type I hyperlipoproteinemia.

Type I hyperlipoproteinemia (type I HLP) is a rare disorder of lipid metabolism characterized by fasting chylomicronemia and reduced postheparin plasma lipoprotein lipase (LPL) activity. Most cases of type I HLP are due to genetic defects in the LPL gene or in its activator, the apolipoprotein CII gene. Several cases of acquired type I HLP have also been described in the course of autoimmune diseases due to the presence of circulating inhibitors of LPL. Here we report a case of type I HLP due to a transient defect of LPL activity during puberty associated with chronic idiopathic urticaria (CIU). The absence of any circulating LPL inhibitor in plasma during the disease was demonstrated. The LPL genotype showed that the patient was heterozygous for the D9N variant. This mutation, previously described, can explain only minor defects in the LPL activity. The presence of HLP just after the onset of CIU, and the elevation of the LPL activity with remission of the HLP when the patient recovered from CIU, indicate that type I HLP was caused by CIU. In summary, we report a new etiology for type I HLP - a transient decrease in LPL activity associated with CIU and with absence of circulating inhibitors. This is the first description of this association, which suggests a new mechanism for type I HLP.

Adolescent↗
PubMed1992

The involvement of polymorphonuclear leukocytes in the pathogenesis of bronchopneumonia in calves. VI. Superoxide dismutase and lipoprotein lipase activities.

The kinetics of superoxide anion production in polymorphonuclear leukocytes of bronchopneumonic calves, as well as superoxide dismutase and lipoprotein lipase activities in the blood plasma of these animals were studied. Granulocytes of bronchopneumonic calves were found to produce 10 times as much O2- radicals as those of healthy animals. Superoxide dismutase and lipoprotein lipase activities were lower in the plasma of bronchopneumonic calves. Escherichia coli endotoxin was found to stimulate superoxide anion production in polymorphonuclear leukocytes in a dose-dependent manner. These facts suggest that an endogenous mediator, probably cachectin or some other monokine(s), plays a role in granulocyte activation during calf bronchopneumonia.

Amino Acid Sequence↗
PubMed1976

Hydrolysis of tri- and monoacylglycerol by lipoprotein lipase: evidence for a common active site.

The relationship between triacylglycerol and monoacylglycerol hydrolyzing activities of purified rat heart lipoprotein lipase was studied using emulsified trioleoylglycerol and micellar or albumin-bound monooleoylglycerol as substrates. The maximal reaction rates obtained with the two substrates were similar (650 and 550 nmol of fatty acid released per min per mg of protein, respectively). Addition of apolipoprotein C-II or serum increased the maximal reaction rate for the trioleolyglycerol hydrolyzing activity about four-fold, but had no effect on the monooleolyglycerol hydrolyzing activity. Hydolysis of the two substrates apparently takes place at the same active site of the enzyme since (1) mutual competitive inhibition between the substrates could be demonstrated; (2) the rate of inactivation of enzymatic activity with the two substrates in 1.2 M NaCl was the same; (3) similar losses of hydrolytic activity with tri- and monooleoylglycerol were observed in the presence of low concentrations of n-butyl (p-nitrophenyl) carbamide; (4) inhibition of both hydrolytic activities by this compound could be prevented by prior exposure of lipoprotein lipase to either substrate.

Amides↗
PubMed1992

Interaction of lipoprotein lipase with p-nitrophenyl N-alkylcarbamates: kinetics, mechanism, and analogy to the acylenzyme mechanism.

The interaction of lipoprotein lipase with p-nitrophenyl N-alkylcarbamates [PNPOC(=O)-NHCnH2n+1; n = 4, 8, and 12] proceeds by the three-stage mechanism shown below. After reversible [formula: see text] formation of the enzyme-carbamate complex (EC), rapid carbamylation (kc) precedes slow decarbamylation. Therefore, in short-term assays (less than or equal to 30 min) of lipoprotein lipase catalyzed hydrolysis of p-nitrophenyl butyrate, activity is rapidly lost. The inhibition by p-nitrophenyl N-butylcarbamate follows saturation kinetics, which allows determination of Kc = 5.4 +/- 0.9 microM and kc = (4.9 +/- 0.7) x 10(-2)s-1. Saturation kinetics are not observed for the longer inhibitors p-nitrophenyl N-octylcarbamate and p-nitrophenyl N-dodecylcarbamate. Rather, plots of the pseudo-first-order rate constant for activity loss versus inhibitor concentration are concave upward, consistent with inhibitor binding to two sites on the enzyme. The inhibition phase is sufficiently rapid that p-nitrophenyl N-octylcarbamate can be used to titrate enzyme active sites. On the other hand, long-term assays (greater than 5 h) show sequential inhibition and activity return phases, and from the activity return phase kd is calculated. The long-term activity time course is accurately simulated by Runge-Kutta integration of the differential equations for the three-stage mechanism. These approaches have been used to characterize the kinetics of interaction of the enzyme with the carbamate inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1977

[Metabolic activity of goat adipose tissue at the end of gestation and at the beginning of lactation: level of deoxyribouncleic acid content and lipoprotein lipase activity].

In the goat the passage from late pregnancy to early lactation is accompanied by a decrease of the epiploon lipoprotein lipase activity and an increase in the epiploon DNA content. The between-goat variations allow us to emphasize a linear relation between the lipoprotein lipase activity decrease and the reduction of the epiploon volume, expressed on a DNA basis. These parameters, used as indicators of the adipose tissue metabolic status, could contribue to the determination of a feeding strategy adapted to high yield milking Ruminants.

Adipose Tissue↗
PubMed2003

Effect of obesity on HDL and LDL particle sizes in carriers of the null P207L or defective D9N mutation in the lipoprotein lipase gene: the Québec LipD Study.

BACKGROUND: We have recently demonstrated that French Canadians bearing a mutation in the lipoprotein lipase (LPL) gene present an impaired lipoprotein-lipid profile characterized by small low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles compared with healthy subjects. It has also been documented that obesity has a significant impact on HDL and LDL particle sizes. OBJECTIVE: To examine the extent to which obesity modulates HDL and LDL particle sizes among carriers of mutations in the LPL gene. SUBJECTS: Analyses were carried out in 206 heterozygous carriers of the D9N mutation (N=118) or the P207L mutation (N=88). MEASUREMENTS: Lipoprotein particle sizes were measured on whole plasma by nondenaturing polyacrylamide gradient gel electrophoresis. RESULTS: In general, body mass index (BMI) and waist circumference were significant correlates of LDL and HDL particle sizes among heterozygous carriers of the P207L or D9N mutation in the LPL gene, with relatively similar associations among men and women. Multivariate analyses indicated that variations in waist circumference but not BMI were an independent predictor of variations in both HDL particle size (5.2%, P=0.0005) and LDL particle size (5.9%, P=0.01) in the entire group of heterozygotes for LPL mutation in a model that included the nature of the LPL mutation (D9N vs P207L), gender, age, cholesterol and plasma TG levels. Interestingly, there was a significant interaction between plasma TG levels and waist circumference or BMI in modulating HDL particle size. Indeed, an increased waist circumference or BMI was associated with a significant reduction in HDL particle size among subjects with plasma TG levels 3.5 mmol/l). CONCLUSION: These results suggest that abdominal obesity, more so that overall obesity, is an important determinant of variations in LDL and HDL particle size among heterozygous carriers of mutations in the LPL gene, perhaps further contributing to modulate the risk of CHD in these individuals.

Body Mass Index↗
PubMed1981

Effect of fasting on free fatty acid, glycerol and cholesterol concentrations in blood plasma and lipoprotein lipase activity in adipose tissue of cattle.

Contributing factors in the regulation of triglyceride deposition in and fatty acid release from bovine adipose tissue were investigated. Six Holstein steers were fasted for 9 days and then refed for 41 days. Blood samples from the jugular vein and adipose tissue samples from backfat biopsies were taken during fasting and refeeding periods. Concentrations of plasma free fatty aids, glycerol and cholesterol and activity of lipoprotein lipase in adipose tissue from fasted and refed steers were measured. Plasma free fatty acid concentration increased almost eightfold during fasting. After 4 days of refeeding, free fatty acids in plasma had returned to basal concentration. Fasting had no effect on plasma cholesterol concentration; during refeeding, concentration decreased slightly and then returned to the basal concentration. Lipoprotein lipase activity decreased to 37% of the basal concentration during fasting and increased to 100% above prefasting values during refeeding. Significant changes in plasma free fatty acid and glycerol concentrations and in activity of lipoprotein lipase in adipose tissue during fasting and refeeding suggest that fatty acid mobilization and triglyceride uptake by adipose tissue of cattle adapt to great changes in energy intake. Correlations of measured blood metabolites in fasted and refed steers demonstrate that changes in rates of lipolysis and of triglyceride uptake by adipose tissue vary in a reciprocal manner.

Adipose Tissue↗
PubMed2006

. Association of HindIII and PvuII genetic polymorphisms of lipoprotein lipase with lipid metabolism and macrovascular events in type 2 diabetic patients.

AIM: Lipoprotein lipase (LPL) is a key enzyme of lipid metabolism, and its genetic polymorphism may be a candidate for modulating lipid parameters in type 2 diabetic subjects (D2). METHODS: In a group of 404 type 2 diabetic patients, aged 59.5+/-10.8y, BMI=28.9+/-5.3 kg/m2, HbA1c=8.2+/-1.9%, we studied the H and P polymorphisms at the LPL locus detectable with the restriction enzymes HindIII and PvuII. Patients were separated into 229 males (17H1H1, 84H1H2, 128H2H2 and 51P1P1, 110P1P2, 68P2P2) and 175 females (16H1H1, 69H1H2, 90H2H2 and 51P1P1, 85P1P2, 39P2P2), and compared on the basis of their lipid parameters and their macrovascular complications. RESULTS: Triglyceride (TG) and HDL-cholesterol(c) concentrations differed between patients with and without coronary heart disease (CHD) (3.44+/-2.09 and 1.96+/-1.40 mmol/l for TGs and 1.05+/-0.24 and 1.34+/-0.40 mmol/l for HDL-c, P<0.001). HDL-c concentrations were lower in male H2H2 and P2P2 subjects (P<0.001), and TG levels were higher in male H2H2 and P2P2 subjects (P<0.0001 for Hind III and P<0.05 for PvuII). Allele frequency of the HindIII and PvuII restriction site was similar to those reported in other Caucasian populations and the presence of the H2/P2 variants was significantly higher in CHD patients. The prevalence of CHD in this population was 18% but was 29% in H2H2 and 38% in P2P2 subjects (P<0.02). CONCLUSION: Thus, HindIII and PvuII polymorphisms seem to exert a modulating role on lipid profile particularly in male D2, contributing to increase the risk of macrovascular events.

Aged↗
PubMed2006

Lipoprotein lipase gene polymorphism at the PvuII locus and serum lipid levels in Guangxi Hei Yi Zhuang and Han populations.

BACKGROUND: Hei Yi (which means "black worship" and "black dressing") Zhuang is a specific subgroup of the Zhuang nationality in China. Little is known about the relationship between genetic factors and lipid profiles in this population. Therefore, the present study was undertaken to compare the effects of lipoprotein lipase gene polymorphism at the PvuII locus on lipid levels in the Guangxi Hei Yi Zhuang and Han populations. METHODS: A total of 325 Hei Yi Zhuang subjects aged from 20 to 80 years were surveyed using stratified randomized cluster sampling. Serum levels of lipids and apolipoproteins were measured. Gene polymorphism was determined using polymerase chain reaction and restriction fragment length polymorphism. The results were compared with those for 331 matched Han subjects living in the same district. RESULTS: Serum levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol and apolipoprotein B were significantly lower in Hei Yi Zhuang than in Han subjects (p<0.05-0.01), whereas the levels of high-density lipoprotein cholesterol and the ratio of apolipoprotein A1 to apolipoprotein B were significantly higher in Hei Yi Zhuang than in Han subjects (both p<0.01). The allelic frequencies for P+ and P- were 52.92% and 47.08% in Hei Yi Zhuang, and 58.46% and 41.54% in Han subjects (p<0.05), respectively. The frequencies of P+P+, P+P- and P-P- genotypes were 23.08%, 59.69% and 17.23% in Hei Yi Zhuang, and 29.31%, 58.31% and 12.38% in Han subjects (p>0.05), respectively. There were no significant differences or no significant correlation between serum lipid parameters and genotypes in Hei Yi Zhuang or Han subjects, or for the combined population of Hei Yi Zhuang and Han (all p>0.05). CONCLUSIONS: The allelic frequencies of the lipoprotein lipase gene at the PvuII locus in Hei Yi Zhuang were different from those in Han subjects, but the genotypic frequencies in Hei Yi Zhuang subjects were not different from those in Han subjects. There was no significant correlation between polymorphism of the lipoprotein lipase gene at the PvuII site and serum lipid levels in the two ethnic groups.

Adult↗
PubMed1992

Interaction of size-fractionated heparins with lipoprotein lipase and hepatic lipase in the rat.

Heparin and heparin partially depolymerized by enzymic digestion were separated into six size fractions. Hep 1 (tetrasaccharides), with a mean M(r) of 1200, did not release significant amounts of either lipoprotein lipase (LPL) or hepatic lipase (HL) on intravenous injection into rats. Hep 2 (mainly octa- and deca-saccharides), with a mean M(r) of 2400-3000, released both lipases. To evoke the same plasma activity of LPL and HL required about 10 times more by weight, or about 40 times more molecules, of this heparin than of hep 5 (mean M(r) 12,000, similar to conventional heparin). Hep 5 impeded binding and degradation of 125I-labelled bovine LPL by perfused rat livers. In contrast, hep 2 had no detectable effect on these processes. This demonstrates a difference between the sites in the liver that mediate binding, uptake and degradation of LPL, and the extrahepatic sites that bind functional LPL, and the hepatic sites that bind functional HL. After injection of 3.25 mg of hep 5/kg body weight, plasma LPL activity rapidly rose and then remained high for at least 1 h. With hep 2, plasma LPL also rose rapidly, but then decreased to almost basal by 1 h. When a labelled triacylglycerol emulsion was injected 1 h after the heparins, the fractional catabolic rate was enhanced in the rats that had received conventional heparin, as expected from the high plasma LPL activity, but decreased compared with controls in rats that had received hep 2, indicating that available LPL had been depleted through enhanced transport to and uptake in the liver.

Animals↗
PubMed1990

Release of lipoprotein lipase and hepatic lipase activities. Effects of heparin and a low molecular weight heparin fragment.

Unfractionated heparin and a low molecular weight heparin fragment (LMWH, mean molecular weight 5000) were compared with respect to the ability to release lipoprotein lipase (LPL) and hepatic lipase (HL) from tissue binding sites. The investigations were carried out in vivo and in vitro in man and in the rat. The in vivo release of LPL activity was greater with heparin in both species. The release of HL activity was equal with both heparins in man, but greater with unfractionated heparin in the rat. In the in vitro studies the LMWH fragment consistently released more LPL activity from the tissues investigated, i.e. fat, skeletal muscle and heart muscle. With isolated adipocytes, however, we could not demonstrate any difference between the two heparins with respect to their lipase-releasing effect. In liver tissue homogenate the two heparins showed the same ability to release HL activity. It is concluded that not only biochemical differences between the two heparins are of importance for the difference in the lipolytic effect. The possibility of different rheological behaviours of the two heparins in the capillary lumen, which might partly explain the greater in vivo lipolytic effects of heparin, is discussed. It is suggested that LMWH enters the tissue preparation more readily in vitro, thereby exerting a greater lipase-releasing effect than heparin.

Adipose Tissue↗
PubMed2006

Relationship between preheparin lipoprotein lipase mass concentration in serum and bare metal stent restenosis.

OBJECTIVES: Insulin resistance or inflammation is known to be related with lipoprotein lipase activity and these factors are also closely associated with the pathogenesis of bare-metal stent restenosis. This study examined the relationship between preheparin lipoprotein lipase protein (preheparin LpL mass) concentration in serum and bare-metal stent restenosis. METHODS: A total of 121 lesions in 112 patients who underwent bare-metal stent implantation using NIR stent or S660/670 stent were examined. Subjects were divided into two groups (N group; patients with normal preheparin LpL mass concentration, n = 50 or L group; patients with low preheparin LpL mass concentration, n = 71) according to the mean levels of preheparin LpL mass concentration (male 39.3 ng/ml, female 50.6 ng/ml). RESULTS: There were no differences in percutaneous coronary intervention or angiographical characteristics. The L group had a significantly higher incidence of restenosis rate and target lesion revascularization than the N group (N group vs L group: 8.0% vs 42.3%, p < 0.0001; 8.0% vs 33.8%, p = 0.0008, respectively). Homeostatic model assessment of insulin resistance as a marker of insulin resistance and high sensitive C-reactive protein concentration were significantly higher in the L group than the N group. Multiple regression analysis showed that only low preheparin LpL mass concentration was an independent factor for restenosis (t value = 3.6, p = 0.0005). CONCLUSIONS: Preheparin LpL mass concentration is closely associated with bare-metal stent restenosis and preheparin LpL mass concentration may be an important marker for the selection of bare-metal stent or drug-eluting stent.

Aged↗
PubMedDate not supplied

Changes in aortic glycosaminoglycans and lipoprotein lipase activity in rats with age and atheroma.

The changes in the individual glycosaminoglycans of the aorta and in lipoprotein lipase activity of the aorta, liver and heart have been studied at various stages in the development of mild atheroma in the rat. Three responses were seen: (a) Hyaluronic acid initially decreased, then increased; (b) Heparan sulphate and chondroitin sulphates A and C initially increased, then decreased. (c) Chondroitin sulphate-B and heparin increased with progressing lipid infiltration and decreased markedly only in the later stages. Ageing changes were also investigated in the rat aorta: total cholesterol, phospholipids and triglycerides increased progressively from weaning to 9 months of age. Hyaluronic acid decreased after weaning, reached a minimum at 6 months and then increased thereafter. Heparan sulphate and chondroitin sulphate-C reached a maximum at 6 months and then decreased thereafter. Chondroitin sulphates A and B showed a similar but less marked pattern of change with age. Heparin progressively increased with age. Aortic lipoprotein lipase activity increased in the early stages of atheroma and then decreased as the lipid infiltration became more severe. The ageing study showed that enzyme activity was quite high at weaning. decreased considerably at 3 months, but thereafter fell only slightly.

Age Factors↗
PubMed2001

Nutrient regulation of post-heparin lipoprotein lipase activity in obese subjects.

This study examines the immediate effect of ingestion of oral carbohydrate and fat on lipoprotein lipase (LPL) activity post-heparin in six lean and six obese age-matched women. Subjects were given, on two separate occasions, 340 kcal carbohydrate or an equicaloric amount of fat, both in 300 ml of water. Post-heparin LPL activity (10,000 U) was measured on each occasion 120 minutes after ingestion of the meal. Following oral carbohydrate postprandial plasma insulin levels were significantly higher in obese subjects than in lean (p < 0.01). Impaired glucose tolerance was seen in the obese group. GIP secretion was similar in lean and obese subjects both during oral fat and carbohydrate ingestion. GLP-1 secretion post-carbohydrate was lower in obese subjects. Total LPL activity unadjusted for body weight was similar in the two groups after carbohydrate administration but was significantly lower when adjusted per kg body weight. Total LPL activity was lower in the lean group at 130 minutes after fat administration (p < 0.02). Fasting serum triglycerides were higher in the obese group and were inversely related to the post-carbohydrate LPL activity (r = - 0.65, p < 0.02). Intraluminal lipoprotein lipase activity is not increased in established obesity. Fat and carbohydrate nutrients may affect LPL activity differently in lean and obese subjects.

Adult↗