Effects of lovastatin and gemfibrozil on high-density lipoprotein subfraction density and composition in patients with familial hypercholesterolemia.

The effects of gemfibrozil and lovastatin treatment on composition and hydrated density distribution of high-density lipoprotein (HDL) were studied in 21 patients with heterozygous familial hypercholesterolemia with the use of HDL density gradient ultracentrifugation. At baseline the patients with familial hypercholesterolemia had a markedly reduced or missing HDL2 subfraction and their HDL3 was more dense with reduced content of cholesteryl ester and increased content of triglyceride compared with HDL of control subjects with normal lipid values. Gemfibrozil and lovastatin caused primarily similar alterations in HDL components in HDL2 and HDL3 subfractions. Both agents increased apolipoprotein AI and apolipoprotein AII concentrations significantly in HDL2, whereas the apolipoprotein changes in HDL3 were relatively smaller. The difference between the effects of these two agents was related to the HDL lipid composition. Gemfibrozil increased the cholesterol concentrations of HDL2 and HDL3 (p less than 0.05 for both), and lovastatin caused significant increases in HDL2 (p less than 0.05) and HDL3 phospholipids (p less than 0.01). The observed similarity of qualitative alterations in HDL subfractions produced by these two agents in patients with familial hypercholesterolemia differs from those reported in other types of hyperlipidemia and is probably a consequence of the basic abnormalities in HDL that are characteristic of familial hypercholesterolemia.     

Pharmacokinetics and pharmacodynamics of pravastatin in children with familial hypercholesterolemia

BACKGROUND: Pravastatin is a widely used statin in adults, but its pharmacokinetics in children is not known. Our aim was to determine the single-dose pharmacokinetics and the lipid-lowering effect and safety of short-term administration of pravastatin in children. METHODS: Twenty children (age range, 4.9-15.6 years) with heterozygous familial hypercholesterolemia ingested a single dose of 10 mg pravastatin. Plasma concentrations of pravastatin were measured for up to 10 hours. The patients then took 10 mg pravastatin orally once daily for 8 weeks. The concentration of serum lipids and safety laboratory parameters were measured before and after 8 weeks of treatment. RESULTS: The mean peak plasma concentration (C(max)) of pravastatin was 15.7 ng/mL (range, 1.6-55.0 ng/mL), and the mean time to reach C(max) was 1.4 hours (range, 0.5-4 hours). The mean elimination half-life of pravastatin was 1.6 hours (range, 0.85-4.2 hours). The area under the plasma concentration-time curve of pravastatin ranged from 5.7 to 58.9 ng. h/mL (mean value, 26.6 ng. h/mL). By 8 weeks of treatment, the serum concentration of total cholesterol had decreased 18% (P <.0001); low-density lipoprotein cholesterol, 21% (P <.0001); and triglycerides, 18% (not significant, P =.18). The concentration of high-density lipoprotein cholesterol had increased 8% (not significant, P =.13). Few transient adverse events occurred. No increases in serum alanine aminotransferase, creatine kinase, or creatinine level were observed. CONCLUSIONS: The pharmacokinetic and pharmacodynamic profile of pravastatin in children is similar to that reported for adults. In the short term, the daily dose of 10 mg pravastatin was well tolerated and moderately effective in decreasing the serum cholesterol concentration. However, further studies are needed on the long-term safety and efficacy of pravastatin in children.     

LDL-apheresis in treatment of two patients with heterozygous familial hypercholesterolemia and extremely elevated lipoprotein (a) levels

In hyperlipidemia and, in particular, elevated lipoprotein (a) [Lp(a)] levels there appears to be pronounced linkage between the development and progression of atherosclerosis. Our study concerned two Caucasian male patients with heterozygous forms of familial hypercholesterolemia and extremely high Lp(a) concentrations. Maximal diet regimens and the use of lipid lowering drugs achieved a serum total-, LDL-cholesterol and triglyceride reduction of up to 30%, but no reduction of the Lp(a) level was discernible. Both patients suffered three myocardial infarctions and several coronary angiographies with percutaneous transluminal angioplasties (PTCA) were necessary. In 1989, we commenced treatment with LDL-apheresis. At present, after 78 LDL-aphereses in the case of the 41-year-old patient (48 months, dextran sulfate adsorption, KANEKA, Japan) and 38 aphereses in the case of the 35-year old patient (8 months, immunoadsorption, special Lp[a] columns, LIPOPAK, POCARD, Russia), the Lp(a) has dropped an average of 53%, total cholesterol 31%, LDL-cholesterol 40% and triglycerides 42%. During this period neither mycardial infarctions nor cardiac complaints were observed. In the course of treatment, both patients experienced an improvement in general well-being and increased performance. These results are very encouraging: LDL-apheresis may be effective in the treatment of patients, the only risk factor for premature atherosclerosis being an extremely high Lp(a) concentration.     

Three low density lipoprotein apheresis techniques in treatment of patients with familial hypercholesterolemia: a long-term evaluation.

Low density lipoprotein (LDL) apheresis is a treatment option for patients with severe hypercholesterolemia not adequately responding to drug treatment who have developed coronary heart disease. We regularly treated 18 patients with immunoadsorption, 8 with heparin induced extracorporeal LDL precipitation (HELP) and 8 with dextran sulfate adsorption for a mean of 4.6 +/- 2.6 years. The effects on LDL cholesterol, high density lipoprotein (HDL) cholesterol, and lipoprotein (a) were comparable among all 3 techniques. Twelve patients were treated for longer than 5 years and 18 patients for longer than 3 years. The evaluation of coronary angiograms (23 patients) revealed a definite regression of coronary lesions in 3 patients; in all other patients, there was a halt in progression. Three patients suffered a sudden cardiac death and 1 patient a nonfatal myocardial infarction due to the occlusion of a coronary bypass. In 9 of 11 patients, no atherosclerotic lesions developed in the coronary bypasses. No severe side effect of either procedure was observed. In conclusion, aggressive lipid lowering by LDL apheresis can stabilize coronary atherosclerosis in most patients.     

Differential low density lipoprotein hydrated density distribution in female and male patients with familial hypercholesterolemia.

The low density lipoprotein (LDL) hydrated density distribution and composition was studied by using density gradient ultracentrifugation in 26 heterozygous familial hypercholesterolemia patients (FH) (13 females and 13 males) and 28 normolipidemic subjects (14 females and 14 males). The average peak hydrated density of LDL mass in female FH patients was 1.0301 g/ml as compared with 1.0333 g/ml in male FH patients (P less than 0.01) indicating less dense LDL particles in females. A similar difference in the average peak density was observed between normolipidemic females and males (1.0315 g/ml and 1.0342 g/ml, respectively; P less than 0.001). The FH males had a significantly lower mean triglyceride (Tg) content in their LDL (4.8%), lower Tg to apolipoprotein B (Apo B) weight ratio (0.24) and higher cholesteryl ester (CE) to triglyceride weight ratio (9.11) in comparison to FH females (Tg 6.2%; Tg/Apo B 0.31; CE/Tg 5.99), P less than 0.05 in all. Similar LDL composition differences were also observed between normolipidemic males and females.     

Decrease of thyroid hormones in patients with familial hypercholesterolemia during dextran sulphate low-density lipoprotein apheresis

Removal of low-density lipoproteins from plasma by dextran sulfate adsorption (DSA) in FH patients entails a decrease in plasma levels of thyroid hormones (?28.5% and ?18.7%, respectively, for T3 and T4). This suggests that FH patients have a greater than normal fraction of thyroid hormones bound to lipoproteins, due to their expanded lipoprotein pool.     

家族性高胆固醇血症患者二例的LDLR基因复合杂合新突变分析

目的 探讨2例临床确诊的湖北籍FH患者的LDLR基因突变状况,为FH的基因诊断提供依据.方法 收集2例临床确诊的FH患者及其父母血脂检测指标等临床资料,通过PCR扩增LDLR基因的1～18个外显子和内含子区域,再将扩增产物进行正、反双向核苷酸序列分析,并与GenBank中LDLR基因的正常序列对比找出突变后,结合FH先证者的临床表型证实致病突变的类型.结果 氧化酶法测定1号、2号FH先证者血浆TC,分别为12.79、11.98 mmol/L;经核苷酸序列分析,其ApoB100基因涵盖的3 500～3 531区域均未见突变;LDLR基因均为复合杂合突变,1号FH先证者LDLR基因第4外显子的665位碱基G>T为杂合错义突变,且该突变为新的点突变,第9内含子的1 358+32位碱基C>T突变也为新的点突变,并均由其父母遗传.2号先证者第9外显子1 257位碱基C>A突变导致终止密码子提前出现,但其核苷酸改变与比利时报道的C>G不同,第13外显子检测到1 879位碱基G>A杂合错义突变,且分别来源于其父母.结论 2例FH先证者均存在LDLR基因复合杂合突变,1号FH先证者的第4外显子665位碱基G>T和第9内含子1 358+32位碱基C>T、2号FH先证者的第9外显子1 257位碱基C>A突变均为新突变,这可能是导致FH的分子机制.

Abstract：

Objective To determine LDLR gene mutation in 2 clinically diagnosed FH patients from Hubei province and provide basis for gene diagnosis of FH.Methods Clinical data of 2 FH patients and their parents were collected.The promoter region and exon 1 to exon 18 region of LDLR gene were amplified through PCR and the amplified products were analyzed by forward and reverse DNA sequencing.The mutations were identified after comparison with LDLR gene sequence in GenBank.The pathogenic gene mutations were confirmed according to both genotype and phenotype of FH probands.Results The levels of plasma TC of two probands were 12.79 and 11.98 mmol/L.respectively.No gene mutations were detected in region 3 500 to 3 531 of ApoB100. The mutations of LDLR gene were compound heterozygous mutations. The novel mutation 665G > T detected in the exon 4 of No. 1 proband's LDLR gene was heterozygous missense mutation. The novel mutation 1 358 +32C > T was detected in the exon 9 of No. 1 proband's LDLR gene.The mutations 665G > T ( paternal origin) and 1 358 + 32C > T ( maternal origin) were inherited from the parents. A novel mutation 1 257 C > A was detected in the exon 9 of No. 2 proband's LDLR gene, resulting the presence of a premature termination codon, which was different from 1 257 C > G reported in Belgium.Another heterozygous missense mutation 1 879 G > A was detected in exon 13. They were derived from paternal origin and maternal origin, respectively. Conclusions There are three novel gene mutations:665G >T, 1 358 +32C > T, 1 257C > A found in two probands with compound heterozygous mutations in LDLR respectively. They maybe play a potential role in FH pathogensis.     

Hypercoagulable state in patients with hypercholesterolemia: effects of pravastatin.

Molecular markers of the coagulation system and the effects of pravastatin on lipid levels and the coagulation markers were studied in 48 patients (mean age, 55 years) with hypercholesterolemia (plasma total cholesterol levels > 280 mg/dl). Each patient received 10 mg of pravastatin daily for 3 months. Plasma total cholesterol and low-density lipoprotein cholesterol levels decreased significantly during treatment and high-density lipoprotein cholesterol levels increased significantly. Above-normal plasma levels of thrombin-antithrombin III complex, fibrinopeptide A, FDP-D-dimer, plasminogen activator inhibitor-I, and thrombomodulin were found in the patients before treatment; each of these was reduced significantly during treatment. The findings suggest the presence of a hypercoagulable state in hypercholesterolemia and that pravastatin might prevent the hypercoagulable state by reducing hypercholesterolemia.     

The role of low density lipoprotein apheresis in the treatment of familial hypercholesterolemia.

The chief indication for low density lipoprotein (LDL) apheresis is the treatment of homozygous familial hypercholesterolemia (FH), a potentially fatal condition that responds poorly to conventional therapy. Dextran sulfate/cellulose adsorption columns (Kaneka) and on-line heparin precipitation (HELP) are the most popular systems used in LDL apheresis. Weekly or biweekly procedures plus concomitant drug therapy enable LDL cholesterol to be maintained at 30-50% of its untreated level, with regression of xanthomas, arrest of progression of coronary atherosclerosis, and improved life expectancy. However, aortic stenosis may progress despite apheresis and necessitate valve replacement. Better control of hypercholesterolemia results from combining apheresis with a new 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, atorvastatin. LDL apheresis can also be useful in treating drug-resistant FH heterozygotes with coronary disease. However, the FH Regression Study showed no evidence that reduction by apheresis of both LDL and lipoprotein(a), was more advantageous than reduction by combination drug therapy of LDL alone.     

Platelet function and lipoprotein levels after plasma-exchange in patients with familial hypercholesterolaemia

1. Repeated plasma exchange was carried out on three young patients with severe familial hypercholesterolaemia. There was a 3 week interval between each exchange. After a single exchange, plasma cholesterol, apolipoprotein B and low density lipoprotein-cholesterol levels decreased markedly, but pre-exchange levels were not achieved within 2 weeks. High density lipoprotein-cholesterol and apolipoprotein A-I levels also fell but returned to the original concentration after only 5 days. 2. Platelet aggregation and [14C]serotonin release were increased in all three patients and dropped by 20% and 13% respectively after a single plasma exchange. Platelet function in vitro returned to pre-exchange levels with similar kinetics to that observed with the low density lipoprotein concentration. On removal of 100 g of plasma cholesterol, after repeated exchanges, low density lipoprotein concentration and platelet function were significantly decreased in comparison with values before initiation of plasma exchange. In addition there was a marked regression of xanthoma in all three patients. 3. Since this procedure is instrumental in achieving a negative cholesterol balance as well as inhibiting hypersensitive platelets, it may well result in a downgrading of the atherosclerotic risk.     

家族性高胆固醇血症黄色瘤的家系遗传分析

目的:检测中国汉族家族性高胆固醇血症(familial hyper-cholesterolemia,FH)家系低密度脂蛋白受体(LDLR)基因突变,探讨FH发病的分子机制。方法:采用PCR扩增结合核苷酸序列分析检测1例临床诊断为FH纯合子患者及其家系成员LDLR基因启动子和全部18个外显子片段,结果与GenBank公布的该基因正常序列对比找出突变,同时检测载脂蛋白B100(apoB100)基因Q3500R突变,以排除家族性apoB100缺陷症。结果:该患者LDLR基因第12外显子的第1747位和1773位碱基发生替换,前者导致H583Y突变,而后者未发现氨基酸改变。同时未检测出患者及其核心家系成员apoB100Q3500R突变。结论:FH是一常染色体显性遗传性疾病,为基因突变导致LDLR缺陷所致的遗传性疾病。检测相关基因突变对临床干预和遗传指导有参考价值。     

Comparison of two low‐density lipoprotein apheresis systems in patients with homozygous familial hypercholesterolemia

Low‐density lipoprotein ( LDL) apheresis (LA) is a reliable method to decrease LDL‐C concentrations and remains the gold standard therapy in homozygous familial hypercholesterolemia (HoFH). The objective of this study was to compare the efficacy of two LA systems [heparin‐induced extracorporeal LDL precipitation (HELP) vs. dextran sulfate adsorption (DS) on the reduction of lipids, inflammatory markers, and adhesion molecules in a sample of genetically defined HoFH subjects (n = 9)]. Fasting blood samples were collected before and after LA. All subjects served as their own control and were first treated with the HELP system then with DS in this single sequence study. Compared with HELP, DS led to significantly greater reductions in total cholesterol (?63.3% vs. ?59.9%; P = 0.05), LDL‐C (?70.5% vs. ?63.0%; P = 0.02), CRP (?75.3% vs. ?48.8%; P < 0.0001), and TNF‐α (?23.7% vs. +14.7%; P = 0.003). Reductions in the plasma levels of PCSK9 (?45.3% vs. ?63.4%; P = 0.31), lipoprotein (a) (?70.6% vs. ?65.0%; P = 0.30), E‐selectin (?16.6% vs. ?18.3%; P = 0.65), ICAM‐1 (?4.0 vs. 5.6%; P = 0.56), and VCAM‐1 (8.3% vs. ?1.8%; P = 0.08) were not different between the two systems. For the same volume of filtered plasma (3,000 mL), however, HELP led to greater reductions in plasma apoB (?63.1% vs. ?58.3%; P = 0.04), HDL‐C (?20.6% vs. ?6.5%; P = 0.003), and PCSK9 (?63.4% vs. ?28.5%; P = 0.02) levels. These results suggest that both LA systems are effective in reducing plasma lipids and inflammatory markers in HoFH. Compared with HELP, greater reductions in lipid levels and inflammatory markers were achieved with DS, most likely because this method allows for a larger plasma volume to be filtered. J. Clin. Apheresis 31:359–367, 2016. © 2015 Wiley Periodicals, Inc.     

Plasma and biliary cholestanol related to steroid metabolism in familial hypercholesterolemia patients with and without ileal exclusion

Plasma cholestanol is increased in cerebrotendinous xanthomatosis and in sitosterolemia with xanthomatosis. We measured plasma and biliary cholestanol in heterozygous familial hypercholesterolemia patients with (n = 10) and without (n = 12) ileal exclusion. In the unoperated patients plasma cholestanol concentration (12.9 mumol/l) and content (1.2 mmol/mol cholesterol) were slightly higher than in the nonhypercholesterolemic control subjects studied by us. Ileal exclusion had lowered plasma cholestanol concentration but only in proportion to the lowering of plasma cholesterol concentration, and plasma cholestanol content (mmol/mol cholesterol) was similar in the operated and unoperated subjects. Plasma and biliary cholestanol contents were positively associated. In the unoperated patients the fractional cholesterol absorption and plasma plant sterols, also reflecting sterol absorption, were positively correlated with plasma cholestanol content. Our study suggests, that plasma cholestanol is slightly elevated in familial hypercholesterolemia and that, in addition to plasma lipoprotein level, sterol absorption is important in the regulation of plasma cholestanol level. Ileal exclusion decreases plasma cholestanol in proportion to the decrement in the plasma cholesterol concentration.     

The effect of combined fenofibrate and cholestyramine therapy on low-density lipoprotein kinetics in familial hypercholesterolemia patients

The effects of combined drug treatment (fenofibrate and cholestyramine) have been investigated in vivo by simultaneously determining total and receptor-independent LDL catabolism with 125I-labelled LDL and 131I-labelled LDL coupled with cyclohexanedione. Receptor-mediated catabolism of LDL determined as the difference between the turnover of 125I and 131I, was found to be reduced in heterozygotes with familial hypercholesterolemia. Treatment with combined fenofibrate and cholestyramine markedly stimulated both receptor-mediated (by more than 2-fold) and receptor-independent catabolism. LDL-Apo B and LDL-cholesterol levels were reduced by 38% and 36%, respectively. The combined treatment also reduced the absolute synthetic rate of LDL-Apo B (by 9%). The mechanisms responsible for these kinetic effects are discussed.     

Reduction in cholesterol and low density lipoprotein synthesis after portacaval shunt surgery in a patient with homozygous familial hypercholesterolemia.

The turnover of 125I-labeled low density lipoprotein (LDL) and the total body balance of cholestrol were studied in a 6-yr-old girl with the homozygous form of familial hypercholesterolemia (FH) before and after the surgical creation of an end-to-side portacaval shunt. The results were compared with those of similar studies simultaneously performed in untreated patients with the heterozygous form of FH and with the results of earlier studies performed on normolipidemic subjects. Before shunt surgery, the rate of synthesis of LDL in the FH homozygote (mg/kg per day) was fourfold higher than in normolipidemic subjects and twofold higher than in her heterozygous mother. The fractional catabolic rate for LDL in the homozygote was decreased to 33% of normal control values. The rate of cholesterol synthesis, estimated by chemical sterol balance, was higher in the FH homozygote than in two FH heterozygotes of similar age studied simultaneously. When considered in relation to the markedly elevated level of plasma cholesterol, the observed rate of cholesterol synthesis in the FH homozygote was inappropriately elevated. Bile acid production was normal in all three children. 5 mo after shunt surgery, the rate of LDL synthesis in the homozygote had declined by 48% as compared with the preoperative value, and this caused a 39% drop in the plasma LDL cholesterol level despite a 17% reduction in the fractional catabolic rate of the lipoprotein. The rate of cholesterol synthesis fell by 62% as compared with the preoperative value. The findings of an inappropriately elevated rate of production of both cholesterol and LDL as well as a reduced fractional catabolic rate for the lipoprotein in the untreated FH homozygote are consistent with results of studies in cultured fibroblasts indicating that the primary genetic defect in FH involves a deficiency in a cell-surface receptor for LDL that regulates both cholesterol synthesis and LDL degradation. Although the mechanism for the decline in production of cholesterol and LDL after portacaval shunt surgery is unknown, it was observed that these changes were associated with marked increases in the plasma concentrations of bile acids and glucagon.     

一个纯合家族性高胆固醇血症家系低密度脂蛋白受体基因突变的检测

目的 检测家族性高胆固醇血症(familial hypercholestero-lemia,FH)患者低密度脂蛋白受体(low density lipoprotein receptor,LDLR)的基因突变.方法 提取家系中,临床通过典型特征和血脂检测诊断为家族性高胆固醇血症患者的基因组DNA,首先检测载脂蛋白B100(apoB100)基因R3500Q突变,以排除家族性apoB100缺陷症(Familial defective apoB100,FDB).然后用降落聚合酶链反应(TOUCH-DOWN PCR)扩增该基因的启动子和全部18个外显子,再用单链构象多态性(SSCP)方法分析PCR产物,并对电泳结果异常者进行DNA测序分析.用ANTHEPROT 5.0软件对突变LDLR进行二级结构分析,然后对突变LDLR进行SWISS MODEL在线三级结构预测.结果 通过SSCP和DNA测序发现该家系患者13号外显子存在A606T的纯合突变,采用ANTHEPROT5.0软件的GORⅠ法对突变型和野生型蛋白质进行二级结构分析,可见突变蛋白的突变区域部分螺旋结构被转角结构和无规卷曲取代,其二级结构发生了改变.突变LDLR三级结构预测未发现主链结构的变化.结论 结果表明.LDLR基因A606T的突变可能是此高胆固醇血症家系的致病原因所在.     

家族性高胆固醇血症患者的临床表现和超声心动图特征

目的 分析家族性高胆固醇血症（FH）患者的临床表现和超声心动图特征.方法 经我院动脉粥样硬化研究室确诊的FH患者41例,女23例,男18例,年龄3～62岁,平均（19.94±14.87）岁.另选取健康人39例作为对照组.采用彩色多普勒超声仪观察两组受检查心脏、瓣膜、主动脉的形态结构和功能.结果 FH患者血清总胆固醇为（13.24±4.36）mmol/L,低密度脂蛋白胆固醇为（10.57±4.41）mmol/L.35例患者皮肤出现黄色瘤,33例为首发症状.二尖瓣反流19例,主动脉瓣反流13例,主动脉瓣钙化6例,主动脉瓣狭窄3例,主动脉根部狭窄8例.FH患者心脏收缩和舒张功能基本正常.结论 FH以高胆固醇血症、特征性黄色瘤、早发的心血管疾病和阳性家族史为主要临床表现.超声心动图检查有瓣膜反流、主动脉口狭窄等表现,能为FH患者动脉粥样硬化的形态和功能变化提供重要依据.