DNA polymorphisms of lipase related genes

We previously determined sequenced the PNLIP gene encoding pancreatic lipase in cell lines of subjects with clinical deficiency of pancreatic lipase (MIM 246600) and found no putative disease-causing mutations. As part of the ongoing analysis of the genomic DNA of these subjects, we now report the development of genomic amplification primers to sequence the coding regions of CLPS, CEL, PLRP1, and PLRP2, encoding pancreatic co-lipase, carboxyl-ester lipase, and pancreatic-lipase-related proteins-1 and -2, respectively. Whereas we found no putative disease-causing missense or nonsense mutations in these samples, we discovered a total of 13 common polymorphisms (12 single nucleotide polymorphisms) in these four genes. Genotypes of these polymorphisms may be useful in future association analyses.     

Single nucleotide polymorphisms of the very low density lipoprotein receptor (VLDLR) gene

The very low density lipoprotein receptor (VLDLR) has a potentially important role in lipoprotein metabolism and Alzheimer's disease. We developed amplification primers for most of the coding region and 3′-untranslated region of VLDLR and used sequencing of genomic DNA to examine these regions of VLDLR in subjects with familial combined hyperlipidemia and in normal controls. We identified ten novel single nucleotide polymorphisms (SNPs) for VLDLR. We also found one rare coding sequence variant, S>R153, in a subject with familial combined hyperlipidemia, which was absent from 2360 normal alleles. The identification of intron–exon boundaries, amplification primers, and SNPs provides tools to investigate VLDLR for genetic association and linkage studies. Received: April 30, 2001 / Accepted: May 1, 2001     

A comparison of the effects of ethinyl estradiol and estradiol valerate on serum and lipoprotein lipids

Serum lipids and lipoproteins were assessed after treatment with 2 mg of oestradiol valerate (E₂V) and 10 μg of ethinyl oestreadiol (EE) in a group of 24 oophorectomised women in a study with an open cross-over design.

E₂V in this oral dose was quite inert in its effect on lipoprotein lipids. Ten micrograms of EE is a dose which in most women is sufficient to alleviate post-menopausal vasomotor symptoms. However, this low dose of EE increased serum triglycerides as a result of increased levels in the ultracentrifugally isolated lipoprotein fractions. Increased levels of serum and lipoprotein triglycerides are considered cardiovascular risk factors in women.     

脂蛋白（a）在主动脉粥样硬化病变中的定位与定量研究

脂蛋白（ａ）［Ｌｉｐｏｐｒｏｔｅｉｎ（ａ），Ｌｐ（ａ）］是动脉粥样化中的独立危险因子，我们采用免疫组织化学技术、免疫电镜技术、酶联免疫吸附法及图像分析技术，研究了正常及不同程度动脉粥样硬化病变的尸检主动脉中Ｌｐ（ａ）分布的量及形式。结果显示：动脉粥样硬化血管壁Ｌｐ（ａ）含量显著增高，各不同病变区域Ｌｐ（ａ）有其独特的分布规律，Ｌｐ（ａ）主要位于细胞外基质中，只在少数泡沫细胞内才发现有Ｌｐ（ａ）。Ａ     

Influence of menopause on serum lipids and lipoproteins

The influence of the menopause on serum lipids and lipoproteins was examined longitudinally at 6-week intervals for 2–3 years in pre-menopausal women undergoing the menopause. Serum lipid and lipoprotein profiles were also examined cross-sectionally in 4 groups of pre-menopausal, perimenopausal and post-menopausal women, who were followed up longitudinally at 3-monthly examinations for 1–2 years. The results covering 1360 examinations and 270 woman-years are reported here.

Serum concentrations of total cholesterol (P = 0.001), low-density-lipoprotein (LDL) cholesterol (P = 0.001) and triglycerides (P < 0.05) increased significantly as a consequence of the menopause and all increases occurred within 6 months of cessation of menstrual periods. High-density-lipoprotein (HDL) cholesterol decreased significantly (P < 0.05) as a consequence of the menopause, but the decline occurred gradually over the 2 years preceding cessation of menses. In addition to the menopausal changes, serum concentrations of total cholesterol and LDL-cholesterol increased gradually in the pre-menopausal and post-menopausal years, but were significantly related to biological age only in the pre-menopausal groups (P < 0.05). Serum triglycerides and HDL-cholesterol levels remained virtually unchanged in the pre-menopausal as well as the post-menopausal groups and were only influenced by the actual menopause.

Serum lipids and lipoproteins are thus significantly altered as a consequence of the menopause. The result is a more atherogenic lipid profile which may partly explain the increased risk of cardiovascular disease observed in post-menopausal women.     

Polymorphisms in PNLIP, encoding pancreatic lipase, and associations with metabolic traits

Pancreatic lipase (EC 3.1.1.3) is an exocrine secretion that hydrolyzes dietary triglycerides in the small intestine. We developed genomic amplification primers to sequence the 13 exons of PNLIP, which encodes pancreatic lipase, in order to screen for possible mutations in cell lines of four children with pancreatic lipase deficiency (OMIM 246600). We found no missense or nonsense mutations in these samples, but we found three silent single-nucleotide polymorphisms (SNPs), namely, 96A/C in exon 3, 486C/T in exon 6, and 1359C/T in exon 13. In 50 normolipidemic Caucasians, the PNLIP 96C and 486T alleles had frequencies of 0.083 and 0.150, respectively. The PNLIP 1359T allele was absent from Caucasian, Chinese, South Asian, and North American aboriginal samples, but had a frequency of 0.085 in an African sample, suggesting that it is a population-specific variant. In an association analysis of 185 African neonates, the PNLIP 1359C/T SNP genotype was significantly associated with concentrations of plasma lipoproteins. These associations were most likely due to linkage disequilibrium with another functional variant at or near PNLIP. Thus, we report three new SNPs for the PNLIP, which may serve as markers for association analyses and for pharmacogenetic studies of pancreatic lipase inhibitors. Received: January 18, 2001 / Accepted: February 19, 2001     

Hypolipidemic Activities of Ficus Racemosa Linn. Bark in Alloxan Induced Diabetic Rats

Ficus racemosa (Moraceae family) is used in traditional system of medicine for the treatment of several disorders including diabetes mellitus. The aim of the study was to investigate the antihyperglycemic and hypolipidemic activities of ethanolic extract of Ficus racemosa bark (FrEBet) in alloxan-induced diabetic rats. A total number of 30 animals were divided into 5 groups of six each. Diabetes mellitus was induced by single intraperitoneal injection of freshly prepared solution of alloxan monohydrate (150 mg/kg bw) dissolved in physiological saline in overnight fasted wistar rats. Dose dependent studies for FrEBet (100–500mg/kg bw) was carried out to find out the effective pharmacological dose (antidiabetic and hypolipidemic) to alloxan-induced diabetic rats. Blood glucose, plasma insulin, total cholesterol, phospholipids, triglycerides, free fatty acids, HDL cholesterol and LDL cholesterol levels in plasma, erythrocyte membranes, liver and kidney were determined by specific colorimetric methods. An increase in blood glucose was accompanied by an increase in total cholesterol, phospholipids, triglycerides, FFA and decrease in HDL choleterol in diabetic rats. Oral administration of FrEBet (300mg/kg bw) to diabetic rats restrored the status of blood glucose, lipids and lipoproteins to near normal range. Our investigation thus shows that FrEBet has potent antidiabetic and hypolipidemic effects in alloxan-induced diabetic rats and these effects were much comparable to that of the standard reference drug, glibenclamide.     

Stimulating effect of intermediate-density lipoproteins (IDL) from hyperlipemic plasma on hepatic lipase

Summary The main lipoprotein density classes, namely very-low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), high-density lipoproteins₂ (HDL₂) and HDL₃ were investigated with respect to their influence on hepatic lipase (HTGL) activity in vitro.Lipoproteins from pooled normal plasma (NP) and from pooled hyperlipemic plasma (HP) were prepared by means of sequential ultracentrifugation. Hepatic lipase was determined radioenzymatically after preincubation with protamine sulfate. It could be demonstrated that IDL from HP were able to stimulate HTGL activity by approximately 100% above the baseline value. HDL₃ from both NP and HP revealed an inhibiting effect on HTGL activity. VLDL, LDL, and HDL₂ exhibited no significant effect on HTGL activity.It is speculated that HTGL could possibly represent a second pathophysiological pathway for the catabolism of IDL in hyperlipemia but this presumption is supported by only a few investigations in vivo.

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Abbreviations HDL₂ High-density lipoproteins₂ - HDL₃ High-density lipoproteins₃ - HP Hyperlipemic plasma pool - HTGL Hepatic lipase - IDL Intermediate-density lipoproteins - LDL Low-density lipoproteins - NP Normal plasma pool - VLDL Very low-density lipoproteins     

Inclisiran—New hope in the management of lipid disorders?

Drugs reducing plasma concentrations of apolipoprotein B–containing lipoproteins have been demonstrated to reduce the risk of cardiovascular disease (CVD) in both primary and secondary prevention. Despite the demonstrated efficacy of statins and ezetimibe on low-density lipoprotein (LDL) concentration and long-term CVD risk, a large number of patients do not achieve their therapeutic goals. The introduction of monoclonal antibodies against proprotein convertase subtilisin/kexin type 9 (PCSK9) protein was a milestone in the treatment of lipid disorders, as their administration leads to unprecedentedly low LDL cholesterol concentrations. Inclisiran represents an entirely new mechanism of PSCK9 protein inhibition in hepatocytes, targeting the messenger RNA for PCSK9. Its administration is necessary only every 3 to 6 months, which is an essential advantage over statin and monoclonal antibody therapy. The infrequent administration regimen can increase the number of patients who maintain their therapeutic goals, especially in patients struggling to comply with daily or biweekly pharmacotherapy. Preclinical studies and Phase I and Phase II clinical trials of inclisiran have demonstrated its tolerability and efficacy in promoting long-term reduction of both PCSK9 protein and LDL cholesterol. The efficacy and safety of inclisiran will continue to be assessed in ongoing and forthcoming trials on larger patient groups. If the results of these trials reflect previously published data, they will add further evidence that inclisiran might be a revolutionary new tool in the pharmacologic management of plasma lipids. This review summarizes the currently available literature data on inclisiran with respect to its mechanism of action, effectiveness, and safety as a lipid-lowering drug for CVD prevention.     

内皮脂酶与动脉粥样硬化

脂酶是一种水溶性酶,能水解甘油三酯、磷脂和胆固醇等一些非水溶性物质,对食物中脂肪的吸收、机体的能量平衡和血浆脂蛋白的代谢起着重要的作用。目前已发现多种具有上述功能的酶,这些酶不仅功能相似,而且氨基酸序列和基因结构相近,由于最初发现的酶主要以甘油三酯为底物,所以将这些酶统称为甘油三酯脂酶基因家族。内皮脂酶(endo-thelial lipase,EL)是唯一由内皮细胞合成的甘油三酯脂酶基因家族新成员,1999年Jaye等[1]和H irata等[2]两个小组分别独立克隆出了EL基因(endotheli-al lipase gene,LIPG)。EL与脂蛋白脂酶(lipoproteinlipase…     

脂蛋白脂酶活性与早发冠心病临床表型关系的初步探讨

目的：探讨脂蛋白脂酶（LPL）活性与早发冠心病临床表型的关系。方法：测定106例早发冠心病患者（病例组）肝素化后血浆LPL活性，血脂参数和血浆C反应蛋白（CRP）浓度，与54例非冠心病者（对照组）进行比较；病例组按照患者临床表型分组，分析LPL活性特点。结果：病例组肝素化后血浆LPL活性低于对照组 [ (26.18±3.90) mmol·L^-1·min^-1 vs (35.27±5.96) mmol·L^-1·min^-1, P<0.05]，急性心肌梗死组LPL活性明显低于不稳定性心绞痛和稳定性心绞痛组。双因素相关分析，LPL与CRP呈显著负相关（r=-0.234，P<0.01）；多因素回归分析，低LPL活性可能是早发冠心病独立的危险因子（OR=6.32，95%CI 1.96-18.24，P<0.05)。结论：低LPL 活性是早发冠心病独立的危险因子，LPL活性与早发冠心病临床表型相关联。     

The influence of the intensity of treadmill walking upon changes in lipid and lipoprotein variables in healthy adults

The purpose of the present study was to compare the acute and delayed effects of low- and moderate-intensity exercise on serum lipoprotein concentrations. Twelve healthy volunteers (five men, seven women), aged 28 (2) years [mean (SEM)], maximal oxygen uptake (O_2max) 48 (3) ml · kg^–1 · min^–1 walked on a treadmill for 90 min, on two separate occasions, in a balanced design. On one occasion walking was at a grade which elicited 32.1 (0.8)% of O_2max, i.e. low intensity, while on the other it elicited 60.1 (1.6)% of O_2max, i.e. moderate intensity (MI). Serum concentrations of total cholesterol (TC), triacylglycerol (TAG), high density lipoprotein cholesterol (HDL-C) and the subfraction HDL₂-C free fatty acids (FFA) and free glycerol were measured in venous blood samples drawn before exercise (after a 12-h fast), during walking and after 1 h and 24 h of recovery. Serum TAG concentrations decreased as a result of the exercise bout over the period of observation (P < 0.05), but this decrease was not different between the two intensities. Changes in serum TC concentrations over time differed between trials (P < 0.05). Serum free glycerol and FFA concentrations increased during exercise bouts, these increases being (P < 0.05) greater with MI. The decrease in serum TAG concentrations during and after a single episode of either prolonged low or moderate intensity exercise may be associated with an increased clearance and/or a decreased secretion of TAG-rich lipoproteins.     

冠心病患者内皮脂肪酶基因Thr111Ile和Gly26Ser多态性与脂蛋白代谢的关系

目的: 探讨冠心病（CHD）患者内皮脂肪酶基因（LIPG）Thr111Ile和Gly26Ser 的多态性与脂蛋白代谢的关系。 方法: 438例冠状动脉造影患者，根据造影结果分为CHD组（242例）和对照组（196 例）。应用酶法测定患者的总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-c）、低密度脂蛋白胆固醇（LDL-c）水平。同时应用聚合酶链反应-限制性内切酶片段长度多态性（PCR-RELP）核苷酸分型技术检测Thr111Ile和Gly26Ser多态性，进行统计学分析。 结果: Thr111Ile在本研究人群中的基因频率分布为CC 76.7％、CT 23.3％、TT 0.0％，等位基因频率为C 88.3％、T 11.7%。CT组HDL-c水平高于CC组（P<0.05），经多因素逻辑回归分析，CT基因仍与高HDL-c水平呈显著相关（P<0.05），CHD与Thr111Ile多态性无显著相关（P>0.05）。未发现Gly26Ser基因变异。结论: 中国汉族人群中存在LIPG基因的Thr111Ile多态性。Thr111Ile多态性中的CT基因致HDL-c水平升高，但未发现其与CHD直接相关。本研究未发现Gly26Ser多态性。     

Ⅰ型胶原与氧化性低密度脂蛋白相互作用的机制研究

目的：阐明胶原与血清低密度脂蛋白（ＬＤＬ）之间的关系。方法：在体外制备了Ⅰ型胶原凝胶,观察可能影响氧化ＬＤＬ（ｏｘ－ＬＤＬ）与胶原结合的几种因素。结果：随着ＬＤＬ氧化程度增加,其与胶原的结合量也增加。结论：这种增加可能主要源于脂蛋白的负电性增加,ＬＤＬ聚集度增大则可降低ＬＤＬ与胶原的结合能力。另外,载脂蛋白Ｂ中赖、精、组、酪氨酸残基的化学修饰,可能在ｏｘ－ＬＤＬ与胶原的结合中起重要作用     

Intrauterine administration of levonorgestrel in two low doses in HRT. A randomized clinical trial during one year: effects on lipid and lipoprotein metabolism

Objective: To investigate the effects on lipid and lipoprotein metabolism of two doses (5- or 10 μg/24 h) of levonorgestrel released from an intrauterine device (IUD) in combination with orally administered estradiol (2 mg estradiol valerate) in perimenopausal women. Design: A 1-year prospective randomized single blind clinical trial. setting: Department of Obstetrics and Gynaecology, Östra Hospital, Göteborg, Sweden. Subjects: Fifty-one perimenopausal women with climacteric symptoms. Outcome measures: Cholesterol in serum and in lipoprotein fractions; high-density lipoprotein 9HDL), low-density lipoprotein (LDL). Triglycerides in serum and in very low-density lipoprotein. Results: In both treatment groups significant elevations in HDL-cholesterol of similar magnitude were observed after 1 month and these changes were maintained during the 12 month observation period. In both treatment groups an initial significant decrease of LDL-cholesterol was observed and the decrement was maintained after 12 months. Serum levels of cholesterol decreased significantly in both groups after 1 month and were maintained after 12 months in the levonorgestrel-IUD (LNG-IUD) 5 μg group. However, the initial reduction of serum cholesterol in the LNG-IUD 10 μg group did not differ from baseline after 12 months. Serum triglyceride levels fluctuated during the observation period. No significant changes occurred. Conclusion: continuous combined HRT with intrauterine administration of levonorgestrel, 5- or 10 μg/24 h, in perimenopausal women was observed to increase HDL-cholesterol and to decrease LDL-cholesterol compared with pretreatment values. the low doses of levonorgestrel did not reverse the beneficial effects on lipid metabolism usually seen after estradiol administration.     

Paraoxonase gene polymorphisms,oxidative stress,and diseases

The paraoxonase (PON) gene cluster contains at least three members, including PON1, PON2, and PON3, located on chromosome 7q21.3–22.1. Until now there has been little insight into the role of the respective gene products in human physiology and pathology. However, emerging evidence from biochemical and genetic experiments is providing clues about the role(s) of the products of these genes, which indicates that PON(s) acts as important guardians against cellular damage from toxic agents, such as organophosphates, oxidized lipids in the plasma low-density lipoproteins. In parallel, substantial data have been published on the association between the polymorphisms of PON(s) and coronary heart disease. It has become clear that the polymorphisms significantly affect the prevalence of coronary heart disease. However, the associations between the PON(s) polymorphisms and most of these conditions were found to be inconsistent when additional populations were investigated. This contribution provides an overview of the status of research of each of the three genes and the available association studies and the potential problems in interpreting the data. We also review the current evidence on the association between PON(s) polymorphisms and diseases other than coronary heart disease and some metabolic quantitative phenotypes, such as plasma lipoproteins, plasma glucose, and birthweight. Finally, we suggest directions for the future that might elucidate the role of the PON genetic polymorphisms in this potentially important function of PON(s) and the role in coronary heart disease and other related diseases.Abbreviations AD Alzheimers dementia - Apo Apolipoprotein - CHD Coronary heart disease - HDL High-density lipoprotein - LDL Low-density lipoprotein - PD Parkinsons disease - PON Paraoxonase     

Glucose tolerance,plasma lipoproteins and tissue lipoprotein lipase activities in body builders

Summary Oral glucose tolerance, insulin binding to erythrocyte receptors, serum lipids, and lipoproteins, and lipoprotein lipase activities of adipose tissue and skeletal muscle were measured in nine body builders (relative body weight (RBW) 118±4%), eight weight-matched (RBW 120±5%) and seven normal-weight controls (RBW 111±3%). The body builders had 50% higher relative muscle mass of body weight (% muscle) and 50% smaller relative body fat content (% fat) than the two other groups (P<0.005). Maximal aerobic power was comparable in the three groups. In the oral glucose tolerance test (OGTT), blood glucose levels, and plasma insulin levels were lower (P<0.05) in the body builders than in weight-matched controls. Insulin binding to erythrocytes was similar in each group. On the basis of multiple linear regression analysis, 87% of the variation in plasma insulin response could be explained by body composition (% muscle and % fat) and .Plasma total cholesterol, low-density lipoprotein (LDL) cholesterol, and very low-density lipoprotein (VLDL) triglyceride concentrations were significantly lower in the body builders than in weight-matched controls. In comparison with the normal-weight group, the body builders had a lower total cholesterol level. High density lipoprotein (HDL) cholesterol, its subfractions (HDL₂ and HDL₃ cholesterol) and lipoprotein lipase (LPL) activities of adipose tissue and skeletal muscle were comparable in all three groups. Partial correlation analysis showed a positive relationship between plasma total triglyceride, total cholesterol and LDL cholesterol on the other hand and the % fat on the other.The results indicate that a shift in body composition from the adipose to the muscular type is associated with 1) lower glucose and insulin levels during the OGTT and 2) decrease in total and VLDL triglyceride and in total and LDL cholesterol levels but unchanged HDL cholesterol level. Thus, body builders are characterized by some metabolic features which decrease the risk of coronary heart disease. In contrast to aerobic training, body building does not influence HDL or its subfractions.     

Chronic lathyrism and atheromatosis in the rat

Summary Temporary chronic administration of Beta-amino-propionitrile (B.A.P.N.) produced morphological and biochemical changes of the aortic wall of rat as well as abnormalities of the plasma lipid levels.A hyperlipidic diet resulted in the blood plasma lipid abnormalities as B.A.P.N. intoxication.Nine weeks of B.A.P.N. followed by 42 weeks of a hyperlipidic diet increased the aortic cholesterol level and induced an atheroma.The diet alone produced only an endothelial lipid overload.The structure of arterial wall played the decisive role in atherogenesis.Supported by Centre National Recherche Scientifique — E.R.A. N 499.     

Association and linkage of LDLR gene variation with variation in plasma low density lipoprotein cholesterol

The role of common variation in the low density lipoprotein (LDL) receptor gene (LDLR) as a determinant of variation in plasma LDL cholesterol in normolipidemic populations is not well established. To address this question, we used both association and linkage analysis to evaluate the relationship between plasma LDL cholesterol and genetic variation in LDLR and in three other candidate genes for lipoprotein metabolism, namely, APOE, PON1, and LPL. We studied a sample of 719 normolipidemic Alberta Hutterites, who comprised 1217 sib pairs. Variation in each of the four candidate genes was significantly associated with variation in plasma LDL cholesterol, but the average effects of the alleles were small. In contrast, sib pair analysis showed that only the LDLR gene variation was linked with variation in plasma LDL cholesterol (P = 0.026). Thus, the common LDLR gene variation was both associated with and linked to variation in plasma LDL cholesterol, suggesting that there is a functional impact of structural variation in LDLR on plasma LDL cholesterol in this study sample. However, the absence of linkage of variation in LDL cholesterol with the other three candidate genes, in particular APOE, is consistent with a lower sensitivity of linkage analysis compared with association analysis for detecting modest effects on quantitative traits. Attributes such as the genetic structure of the study sample, the amount of variance attributable to the locus, and the information content of the marker appear to affect the ability to detect genotype-phenotype relationships using linkage analysis. Received: March 13, 1998 / Accepted: May 11, 1998     

Deficiency of choresteryl ester transfer protein and gene polymorphisms of lipoprotein lipase and hepatic lipase are not associated with longevity

Cholesteryl ester transfer protein (CETP) is one of the key proteins in reverse cholesterol transport (RCT). The role of CETP in atherosclerosis remains controversial. In this study we investigated the associations between polymorphisms of CETP (mutations in intron 14 and exon 15, and Taq1B), hepatic lipase (C-514T), lipoprotein lipase ( PvuII and HindIII), and ATP-binding cassette transporter 1 (R219K) loci and longevity in 256 centenarians and 190 healthy younger controls. Although heterozygous CETP deficiency and the B2 allele of the Taq1B polymorphism was consistently associated with higher HDL-C concentrations both in centenarians and controls, the allelic frequencies of those polymorphisms did not differ between the two groups. The allelic frequencies of other gene polymorphisms in RCT were not different between the two groups. Centenarians with lipoprotein lipase P(-/-) genotype had significantly higher HDL-C concentration than those with P(-/+) or with P(+/+), in contrast, there was no such a relationship among controls. In stepwise multiple regression analysis, serum albumin, CETP deficiency and lipoprotein lipase PvuII genotype were independently associated with HDL-C in centenarians. Sex, CETP deficiency, and the Taq1B genotype were also independently associated with HDL-C; however, lipoprotein lipase PvuII genotype had no significant effect on their HDL-C in controls. In conclusion, we observed that CETP deficiency and other gene polymorphisms in RCT have no impact on longevity for Japanese centenarians.