Decreased production of low density lipoprotein by atorvastatin after apheresis in homozygous familial hypercholesterolemia

Apheresis only partially controls raised low density lipoprotein cholesterol levels in patients with homozygous familial hypercholesterolemia, who usually respond poorly to lipid-lowering drugs. The efficacy and mechanism of action of a new 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, atorvastatin, was therefore investigated in seven homozygotes undergoing apheresis. One receptor-negative and six receptor-defective homozygotes undergoing plasma exchange or LDL apheresis every 2 weeks were studied during 2 months each on placebo and on atorvastatin 80 mg daily. Changes in plasma lipids and mevalonic acid, an index of cholesterol synthesis, were measured and the kinetics of the rebound of low density lipoprotein cholesterol and apolipoprotein B after apheresis were analyzed. All subjects had significant improvements on atorvastatin. Mean decreases in low density lipoprotein cholesterol were 31% greater both pre- and post-apheresis on atorvastatin compared with placebo, accompanied by a 63% decrease in mevalonic acid. Percentage changes in low density lipoprotein cholesterol and mevalonic acid were closely correlated (r = 0.89, P = 0.007). The mean production rates of low density lipoprotein cholesterol and apolipoprotein B were 21% and 25% lower, respectively, on atorvastatin than on placebo (P < 0.005 and <0.02) but changes in mean fractional clearance rates were not statistically significant. We conclude that atorvastatin enhances the efficacy of plasma exchange and low density lipoprotein apheresis in patients who lack low density lipoprotein receptors. This effect appears to be due to marked inhibition of cholesterol synthesis which results in a decreased rate of production of low density lipoprotein.     

Analysis of LDL receptor gene mutations in Italian patients with homozygous familial hypercholesterolemia

The aim of this study was the characterization of mutations of the LDL receptor gene in 39 Italian patients with homozygous familial hypercholesterolemia, who were examined during the period 1994 to 1996. The age of the patients ranged from 1 to 64 years; one third of them were older than 30. Plasma LDL cholesterol level ranged from 10.8 to 25.1 mmol/L. The residual LDL receptor activity, measured in cultured fibroblasts of 32 patients, varied from <2% to 30% of normal and was inversely correlated with the plasma LDL cholesterol level (r=-0.665; P<0.003). The most severe coronary atherosclerosis was observed in those patients with the lowest residual LDL receptor activity (相似文献   

Elevated levels of lipoprotein (a) in children with familial hypercholesterolemia

Lipoprotein(a)[Lp(a)] concentrations and their correlation to total cholesterol (TC), low-density and high-density lipoprotein cholesterol (LDL-C, HDL-C) and triglycerides (TG) were estimated in 20 normal weight children affected with familial hypercholesterolemia (FH) and for comparison in 20 overweight, but otherwise healthy children, matched for sex and age. The mean value of Lp(a) in patients with FH (0.29 g/l, SD = 0.27) was markedly higher than in the control group (0.17g/l, SD = 0.19), but the difference was not statistically significant. However, the frequency distribution of Lp(a) in both groups was different: the proportion of Lp(a) levels above 0.60g/l was significantly greater in patients with FH than in the controls (p < 0.05). These results indicate that even pediatric patients with FH have increased Lp(a) levels. Since Lp(a) elevation above 0.25 to 0.30g/l--in particular in combination with increased LDL concentrations--is is associated with a markedly increased risk of coronary heart disease, cervical atherosclerosis and cerebral infarction, it seems very important to detect these high-risk individuals as early as possible and to treat them appropriately.     

Pregnancy in a patient with homozygous familial hypercholesterolemia undergoing low-density lipoprotein apheresis by dextran sulfate adsorption

Pregnancy and delivery in homozygous familial hypercholesterolemic (HFH) patients is extremely rare. We describe the case of a woman with HFH treated with low-density lipoprotein (LDL) apheresis by dextran sulfate adsorption who became pregnant and reached delivery uneventfully. LDL apheresis was performed biweekly, and lipoprotein analyses in pre-apheresis samples showed progressive increases in triglyceride, total cholesterol, and apolipoprotein (apo) B plasma concentrations. The fractional catabolic rate (FCR) for LDL cholesterol, as estimated by the first-order disappearance constants (k values) of the recovery of LDL cholesterol concentration to basal values after each apheresis session, increased more than threefold from week-24 to week-4 (labor is considered as time 0). After delivery basal values were recovered, but normalization was slower for LDL cholesterol than for the other lipidic parameters. High-density lipoprotein (HDL) showed a different pattern: HDL3 remained stable throughout gestation, whereas HDL2 cholesterol and apo A-I had a maximum at midgestation, then declined, and finally increased again at late gestation. With the exception of this latter increase of HDL2, all the other changes in lipoprotein concentrations during pregnancy and postpartum were similar to those found in healthy women. Thus, LDL apheresis does not interfere with physiologic adaptations of lipoprotein metabolism during pregnancy in HFH patients.     

Flow cytometry with a monoclonal antibody to the low density lipoprotein receptor compared with gene mutation detection in diagnosis of heterozygous familial hypercholesterolemia

We used a fluorescence flow cytometry assay with a monoclonal low density lipoprotein (LDL) receptor-specific antibody to detect LDL receptor expression on blood T lymphocytes and monocytes. We prepared peripheral blood mononuclear cells from patients with genetically verified LDL receptor-defective (Trp66-Gly mutation, n = 17) or receptor-negative (Trp23-stop mutation, n = 17) heterozygous familial hypercholesterolemia (FH) and from healthy individuals (n = 24). The cells were stimulated to express the maximum amount of LDL receptor by preincubation in lipoprotein-deficient medium. A dual-labeling technique allowed flow cytometric analysis of LDL receptor expression on cells identified by fluorescently conjugated surface marker antibodies. Knowing the LDL receptor gene mutation of the FH patients allowed us to compare the diagnostic capability of this functional assay with the DNA diagnosis and to validate the assay with molecular genetics instead of clinical indices of heterozygous FH. T lymphocytes expressed more LDL receptors and gave better diagnostic results than monocytes, and cells from patients with either the Trp66-Gly or the Trp23-stop mutation had variable but significantly reduced LDL receptor expression. The data indicate that this fluorescence flow cytometry assay is unsuitable for diagnosis of individual cases of heterozygous FH but that it may be useful for functionally characterizing mutations in the LDL receptor gene.     

Occurrence of the same peroxidative compounds in low density lipoprotein and in atherosclerotic lesions from a homozygous familial hypercholesterolemic patient: a case report

OBJECTIVE: There has been no reference material for T-lymphocyte subsets for normal children in developing countries. We therefore used T-lymphocyte subset determinations among children in three different studies in Guinea-Bissau to construct age-related reference material and to examine possible determinants of T-lymphocyte subset levels. METHODS: A total of 803 healthy West African children younger than 6 years were included in the three community studies of T-lymphocyte subsets among twins and singletons, after measles infection and after measles immunization. We used the immunoalkaline phosphatase method to determine T-lymphocyte subsets. RESULTS: We found differences by age, sex, and season, whereas there were no significant differences by birth order, twinning, or ethnic group. The CD4+ percentage declined from birth to age 2 years, at which time it started to increase to higher levels at age 4 to 5 years. The CD8+ percentage increased gradually from early infancy to age 2 to 4 years. The leukocyte count peaked at age 12 to 23 months and declined thereafter, whereas the lymphocyte percentage peaked at age 1 to 5 months and declined gradually thereafter. Compared with dry-season results, the lymphocyte percentage, the absolute lymphocyte count, the absolute CD4+ T-lymphocyte count, and the CD4+/CD8+ ratio were significantly lower during the rainy season, whereas the CD8+ percentage was increased during the rainy season. Girls had higher CD4+/CD8+ ratios and lower CD8+ percentages than did boys. CONCLUSIONS: Compared with the limited data on T-lymphocyte subsets available from healthy children in developed countries, Guinean children have markedly lower CD4+ percentages and CD4+/CD8+ ratios and higher lymphocyte percentages during the first 2 years of life, when the pressure of infections is particularly high in Africa.     

Low density lipoprotein receptor mutations in a selected population of individuals with moderate hypercholesterolemia

To evaluate mutations in the low density lipoprotein receptor (LDL-R) gene in moderate primary hypercholesterolemia, a combination of polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP) and direct sequencing, was used to screen the LDL-R gene in a selected population of 82 unrelated individuals with moderate elevation of plasma LDL-C [mean 4.55 +/- 0.55 mmol/l (176.4 +/- 21.6 mg/dl)]. Four subjects (5%) were found to be heterozygotes for missense mutations in the LDL-R gene. These mutations were located in four different exons (exons 6, 7, 15 and 17) and all alters highly conserved residues of LDL-R protein. None of these mutations were detected in 79 normocholesterolemic individuals. The mutation in exon 15 (T705I) was previously reported in a compound heterozygote for familial hypercholesterolemia (FH). In the proband carrying the mutation in exon 17 (R793Q), an in vivo LDL turnover study was performed and it demonstrated a reduction of LDL catabolism. These findings demonstrate that mutations in the LDL-R may occur in primary moderate hypercholesterolemia. They also extend the concept that some FH patients may present with a mild phenotype.     

Receptors of the low density lipoprotein (LDL) receptor family in man. Multiple functions of the large family members via interaction with complex ligands

The LDL receptor family members are endocytic receptors composed of repeated protein modules, including clusters of ligand binding LDL receptor class A (LA) repeats. The large (approximately 600 kDa) members LRP and megalin bind numerous structurally unrelated and often complex ligands at different combinations of sites. LRP is expressed in a wide but restricted set of cell types including hepatocytes, macrophages, smooth muscle cells, and neurons of the CNS. Megalin is expressed in various epithelia including proximal kidney tubules, intestine, and ependymal cells. The two receptors share a multitude of ligands, and their function in vivo is therefore to a large extent determined by their expression pattern. For example, both receptors can endocytose lipoproteins, but this function appears mainly relevant for LRP. In addition, LRP helps regulating urokinase receptor expression on the cell surface via ligand-mediated internalization followed by return of the naked urokinase receptor to the cell surface. Both receptors also have specialist functions. LRP is specific for binding of alpha2-macroglobulin-proteinase complexes and provides clearance of the complexes and of peptides, e.g. cytokines, associated with the complex. Megalin has important functions in vitamin B12 homeostasis since it specifically mediates uptake of the vitamin B12-transcobalamin complex and helps building a storage pool for the vitamin in the kidneys. Moreover, megalin binds cubilin, the recently identified receptor for B12-intrinsic factor complex, thus providing a mechanism for uptake of dietary vitamin B12. Finally, megalin specifically mediates uptake of apolipoprotein J/clusterin, a binding protein for the Abeta peptide implicated in Alzheimer's disease. The binding of multiple complex ligands that belong to distinct physiological systems provides a challenge in future studies aiming at elucidating the role of LRP and megalin in disease mechanisms.     

Leukocyte low density lipoprotein receptor (LDL-R) does not contribute to LDL clearance in vivo: bone marrow transplantation studies in the mouse

The targeted disruption of the low density lipoprotein (LDL) receptor gene in mice results in accumulation of plasma LDL cholesterol and in predisposition to diet-induced aortic atherosclerosis. Although the liver is the central organ for receptor mediated clearance of LDL, the in vivo role of other organs and tissues in LDL catabolism has not been directly studied. Since bone marrow-derived cells such as blood leukocytes and tissue macrophages express LDL receptors and contribute a large mass to the body, we designed bone marrow transplantation (BMT) experiments to reconstitute LDL receptor null mice [LDL-R(-/-)] with marrow obtained from LDL-R wild-type mice [LDL-R(+/+)] and evaluate the effects on parameters of plasma lipid metabolism. Although reconstitution of the transplanted mice with donor bone marrow cells was complete, no differences in plasma lipid levels and lipoprotein distribution were found between groups, irrespective of the diet used, and turnover studies using 125I-labeled LDL showed that LDL receptor expression by leukocytes and macrophages does not significantly contribute to plasma LDL clearance. The complementary experiment of transplanting LDL-R(-/-) marrow into C57BL/6 recipients [LDL-R(-/-)-->LDL(+/+)], performed to evaluate the role of leukocyte LDL-R in normocholesterolemic condition, also produced no effects on plasma lipid parameters. LDL binding studies using macrophages isolated from transplanted mice showed a lack of LDL-R expression. Thus, despite their large number and wide distribution, bone marrow-derived cells do not significantly influence receptor-mediated clearance of plasma LDL.     

In vivo kinetics of lipoprotein(a) in homozygous Watanabe heritable hyperlipidaemic rabbits

In vivo kinetics of lipoprotein(a) [Lp(a)] were investigated in homozygous Watanabe heritable hyperlipidaemic (WHHL) rabbits (an animal model of familial hypercholesterolemia (FH)), and in normolipidemic Japanese White rabbits (controls). 125I-labelled Lp(a) and 131I-labelled LDL were simultaneously injected intravenously. Blood samples were then taken periodically. Kinetic parameters were calculated from the plasma radioactivity decay curves. The fractional catabolic rates (FCRs) of both Lp(a) and LDL (1.355 +/- 0.189 pools per day and 1.278 +/- 0.397 pools per day, respectively) in the WHHL rabbits were significantly (P < 0.005) smaller than those in the control rabbits (2.008 +/- 0.083 pools per day and 2.855 +/- 0.759 pools per day, respectively). In WHHL rabbits, the FCRs of Lp(a) and LDL were similar. However, in control rabbits, the FCR of Lp(a) was significantly (P < 0.01) smaller than that of LDL. In WHHL rabbit organs, the mean ratio of 125I-Lp(a): 131I-LDL, 48 h after injection, normalized to the corresponding isotope ratio in plasma, were 1.525, 1.020, 1.819 and 1.967, in liver, kidney, spleen and bile, respectively. These values were significantly higher than the corresponding values in control rabbits (0.590, 0.677, 0.862 and 0.766, respectively). Our data strongly suggest that Lp(a) clearance is not entirely dependent upon LDL receptors and may be mediated by some other mechanisms.     

Racial differences in the distribution of a low density lipoprotein receptor-related protein (LRP) polymorphism and its association with serum lipoprotein, lipid and apolipoprotein levels

We recently demonstrated that granulocyte-macrophage colony-stimulating factor (GM-CSF) is an autocrine growth factor for human osteoblastic (hOB) cells. Since GM-CSF is a member of the heparin-binding factor family, we examined the interactions between GM-CSF and glycosaminoglycans (GAGs) present in the osteoblast microenvironment. Using a bioassay in which the mitogenic activity of recombinant human (rh) GM-CSF was measured after incubation in the presence of an hOB cell layer or extracellular matrix (ECM) produced by these cells, we showed that rhGM-CSF binds to GAG components present in the ECM and that the bound rhGM-CSF retains its ability to stimulate hOB cell proliferation. Heparan sulfate compounds on the hOB cell surface were also found to sequester GM-CSF. Moreover, treatment with sodium chlorate, an inhibitor of GAG sulfation, suppressed the mitogenic activity of rhGM-CSF on hOB cells. This inhibitory effect was rescued by a low dose of heparin. Heparin was also found to promote the effect of rhGM-CSF on hOB cell proliferation, allowing nonmitogenic high doses of rhGM-CSF to stimulate hOB cell growth. Western blot analysis showed that undersulfation of cellular GAGs by chlorate inhibited the increased tyrosine phosphorylation of proteins involved in GM-CSF signaling in cloned immortalized hOB cells. The data demonstrate that GM-CSF binds to proteoglycans on the hOB cell surface and in ECM produced by these cells and that the bound GM-CSF is biologically active. Furthermore, this study shows that cellular proteoglycans play an essential role in GM-CSF signaling and biological activity in hOBs.     

Treatment effects on serum lipoprotein lipids, apolipoproteins and low density lipoprotein particle size and relationships of lipoprotein variables to progression of coronary artery disease in the Bezafibrate Coronary Atherosclerosis Intervention Trial (BECAIT)

OBJECTIVES: To investigate the mechanisms by which bezafibrate retarded the progression of coronary lesions in the Bezafibrate Coronary Atherosclerosis Intervention Trial (BECAIT), we examined the relationships of on-trial lipoproteins and lipoprotein subfractions to the angiographic outcome measurements. BACKGROUND: BECAIT, the first double-blind, placebo-controlled, randomized serial angiographic trial of a fibrate compound, showed that progression of focal coronary atherosclerosis in young survivors of myocardial infarction could be retarded by bezafibrate treatment. METHODS: A total of 92 dyslipoproteinemic men who had survived a first myocardial infarction before the age of 45 years were randomly assigned to treatment for 5 years with bezafibrate (200 mg three times daily) or placebo; 81 patients underwent baseline and at least one post-treatment coronary angiography. RESULTS: In addition to the decrease in very low density lipoprotein (VLDL) cholesterol (-53%) and triglyceride (-46%) and plasma apolipoprotein (apo) B (-9%) levels, bezafibrate treatment resulted in a significant increase in high density lipoprotein-3 (HDL3) cholesterol (+9%) level and a shift in the low density lipoprotein (LDL) subclass distribution toward larger particle species (peak particle diameter +032 nm). The on-trial HDL3 cholesterol and plasma apo B concentrations were found to be independent predictors of the changes in mean minimum lumen diameter (r=-0.23, p < 0.05), and percent (%) stenosis (r = 0.30, p < 0.01), respectively. Decreases in small dense LDL and/or VLDL lipid concentrations were unrelated to disease progression. CONCLUSIONS: Our results suggest that the effect of bezafibrate on progression of focal coronary atherosclerosis could be at least partly attributed to a rise in HDL3 cholesterol and a decrease in the total number of apo B-containing lipoproteins.     

Identification of a common low density lipoprotein receptor mutation (C163Y) in the west of Scotland

BACKGROUND: The pathological processes by which Helicobacter pylori infection leads to the development of gastroduodenal disease are still incompletely understood. Oxygen-derived free radicals are important mediators of inflammation and potential carcinogens. Furthermore, dietary studies have suggested that antioxidant vitamins may protect against gastric cancer. OBJECTIVE: To determine plasma free radical activity and antioxidant vitamin levels in dyspeptic patients and to correlate the results with H. pylori infection and tobacco smoking. SUBJECTS: Forty-three patients undergoing routine endoscopy for investigation of dyspepsia. METHODS: Plasma free radical activity was determined by measurement of thiobarbituric acid-reactive substances (TBARS). Plasma samples were also assayed for the antioxidant vitamins A, C and E. Gastroduodenal biopsies were obtained from all patients for histological examination. RESULTS: Plasma TBARS levels were significantly higher in H. pylori positive versus negative subjects (P < 0.03), smokers versus non-smokers (P < 0.04) and males versus females (P < 0.01). Multiple regression analysis revealed that after correcting for male sex and smoking there was no significant association between plasma free radical activity and H. pylori infection. Smokers had significantly lower levels of plasma vitamin C than non-smokers (P< 0.05); no differences were seen in vitamin A and E levels. Gender and H. pylori infection did not significantly affect plasma antioxidant vitamin levels. Gastroduodenal disease was present in all of the smokers compared with 67% of the non-smokers (P < 0.05); 69% of the smokers were H. pylori positive versus 53% of the non-smokers. CONCLUSIONS: Tobacco smoking and male sex, both recognized risk factors for gastroduodenal disease, appear to be the major determinants of increased plasma free radical activity in dyspeptic subjects, rather than H. pylori infection. The reason for the higher prevalence of H. pylori infection and gastroduodenal disease in dyspeptic smokers is unclear but may relate to weakened antioxidant defences.     

Low density lipoprotein apheresis improves regional myocardial perfusion in patients with hypercholesterolemia and extensive coronary artery disease. LDL-Apheresis Atherosclerosis Regression Study (LAARS)

OBJECTIVES: In a randomized study we evaluated the effect of biweekly low density lipoprotein (LDL) apheresis plus simvastatin versus medication alone on regional myocardial perfusion. BACKGROUND: In patients with severe hypercholesterolemia, diet and lipid-lowering drugs are often insufficient to achieve optimal LDL cholesterol values. Low density lipoprotein apheresis is a very effective lipid-lowering therapy. Assessment of regional myocardial perfusion enables evaluation of the functional state of the coronary circulation. METHODS: We studied 42 patients with severe hypercholesterolemia and extensive coronary artery disease who were randomized to diet and simvastatin with or without biweekly LDL apheresis. Regional myocardial perfusion was assessed by digital subtraction angiography with videodensitometric calculation of hyperemic mean transit time (HMTT) of contrast medium at baseline and after 2 years of therapy. RESULTS: Low density lipoprotein cholesterol decreased by 63% (to 3.0 mmol/liter) in the LDL apheresis group and by 47% (to 4.1 mmol/liter) in the medication group. Paired HMTT measurements were assessed in 43 regions in the LDL apheresis group and 35 regions in the medication group. In the LDL apheresis group, regional HMTT decreased over 2 years from 3.35 +/- 1.18 (mean +/- SD) to 2.87 +/- 0.82 s (-14%, p = 0.001), whereas no change in the medication group was observed: 2.95 +/- 1.06 to 2.96 +/- 0.90 s (p = NS). In the patient-based comparison, the mean change in HMTT was -0.45 s (-14%, p = 0.01) in the LDL apheresis group and -0.05 s (-2%, p = NS) in the medication group, respectively. Only exercise-induced ischemia improved in the LDL apheresis group. CONCLUSIONS: Biweekly LDL apheresis plus simvastatin decreased time-averaged LDL cholesterol levels by an additional 31% (1.1 mmol/liter) compared with medication alone. After 2 years of therapy, regional myocardial perfusion improved in the LDL apheresis group and remained unchanged in the medication group. Thus, aggressive reduction of LDL cholesterol has a favorable effect on regional myocardial perfusion and alleviates ischemia.     

No association between the low density lipoprotein receptor-related protein (LRP) gene and late-onset Alzheimer's disease in a community-based sample

It is now commonly known that possession of the epsilon4 allele of the apolipoprotein E (APOE) gene confers an increased risk for both familial and sporadic Alzheimer's disease (AD), in a dose-dependent way. Other genes that may play a role in AD, either through independent association with the disease or through modification of the existing APOE risk, have been reported with conflicting results. One such gene, the low density lipoprotein receptor-related protein (LRP) gene, was recently reported by two groups to be associated with AD, although the groups identified different risk-conferring alleles. Both studies were based on clinic-derived AD populations (one American, one French), and both reported only marginally significant results. We have genotyped a community-based AD and control population at this LRP polymorphism and find no association between the variants at that polymorphism and the occurrence of AD. Further, despite the biochemical relationship between LRP and the ApoE protein, we find no significant statistical interaction between the alleles at these loci.     

Identification of the low density lipoprotein receptor-binding site in apolipoprotein B100 and the modulation of its binding activity by the carboxyl terminus in familial defective apo-B100

Familial defective apolipoprotein B100 (FDB) is caused by a mutation of apo-B100 (R3500Q) that disrupts the receptor binding of low density lipoproteins (LDL), which leads to hypercholesterolemia and premature atherosclerosis. In this study, mutant forms of human apo-B were expressed in transgenic mice, and the resulting human recombinant LDL were purified and tested for their receptor-binding activity. Site-directed mutagenesis and other evidence indicated that Site B (amino acids 3,359-3,369) binds to the LDL receptor and that arginine-3,500 is not directly involved in receptor binding. The carboxyl-terminal 20% of apo-B100 is necessary for the R3500Q mutation to disrupt receptor binding, since removal of the carboxyl terminus in FDB LDL results in normal receptor-binding activity. Similarly, removal of the carboxyl terminus of apo-B100 on receptor-inactive VLDL dramatically increases apo-B-mediated receptor-binding activity. We propose that the carboxyl terminus normally functions to inhibit the interaction of apo-B100 VLDL with the LDL receptor, but after the conversion of triglyceride-rich VLDL to smaller cholesterol-rich LDL, arginine-3,500 interacts with the carboxyl terminus, permitting normal interaction between LDL and its receptor. Moreover, the loss of arginine at this site destabilizes this interaction, resulting in receptor-binding defective LDL.     

DALI-the first human whole-blood low-density lipoprotein and lipoprotein (a) apheresis system in clinical use: procedure and clinical results

BACKGROUND: The DALI low-density lipoprotein (LDL) apheresis system is the first whole-blood apheresis system in regular clinical use. DALI stands for direct adsorption of lipoproteins, which describes the basic principle of operation of this newly developed LDL apheresis procedure. METHODS: The selective removal of LDLs and lipoprotein (a) [Lp(a)] is performed in human whole blood by adsorption onto polyacrylate-coated polyacrylamide beads in an adsorber. This article describes the results of the first open multicentre clinical trial in 14 patients in whom the safety and the efficacy of the system were tested. All patients were treated on average 17 times on a weekly basis. In total, 238 sessions were carried out during the study without severe side-effects. On average, 7675 mL of the patients' whole blood was processed in about 2 h. Anticoagulation in the extracorporeal system was carried out by first giving a heparin bolus followed by continuous addition of an acid citrate dextrose (ACD-A) infusion during the treatment. RESULTS: The processing of nearly 1.6 times the patient blood volumes resulted in a reduction in the median LDL-cholesterol level by 66-77% (dependent on the system configuration). The Lp(a) concentrations were reduced by 59-73% (dependent on the system configuration). HDL-cholesterol, blood cell count and the other clinical parameters were not significantly affected. CONCLUSION: Based on this short-term evaluation, the DALI apheresis system is a well-tolerated, effective and simple way of reducing LDL and Lp(a) in human whole blood. The system has been introduced to clinical practice. However, to use the DALI apheresis system in clinical routine, further evaluation of long-term effects is required.     

Precipitation procedures used to isolate high density lipoprotein with particular reference to effects on apo A-I-only particles and lipoprotein(a)

Analysis of high density lipoprotein (HDL) isolated from serum without major hypertriglyceridaemia and by five different precipitation methods showed that there were no significant differences in total cholesterol and triglyceride concentrations in the HDL supernatants prepared by the different methods but that free cholesterol, phospholipid, apolipoprotein (apo) A-I and HDL particles containing apo A-I but not apo A-II (LpAI) concentrations were significantly lower for heparin-manganese chloride method 2 (final manganese chloride concentration 92 mmol/l) compared with the other methods. Modest differences in HDL cholesterol, apo A-I and LpAI were observed between heparin-manganese chloride method 1 (final magnesium concentration 46 mmol/l) and the dextran sulphate, phosphotungstate and polyethylene glycol 6000 methods. Lipoprotein(a) (Lp(a)) and apo B were undetectable in the HDL supernatants, indicating that apo B-containing lipoproteins including Lp(a) were essentially completely removed by all the precipitation procedures.     

beta-VLDL hypercholesterolemia relative to LDL hypercholesterolemia is associated with higher levels of oxidized lipoproteins and a more rapid progression of coronary atherosclerosis in rabbits

The accumulation of the oxidized apolipoprotein, apoB-100, containing lipoproteins in the arterial wall and the progression of coronary atherosclerotic lesions in rabbits with beta-VLDL and LDL hypercholesterolemia was compared. In New Zealand White (NZW) rabbits on a 0.125% cholesterol diet, LDL cholesterol levels increased from 14 +/- 1 mg/dL (mean +/- SEM; n = 9) to 170 +/- 34 mg/dL (n = 10, P = .0002). On 0.5% cholesterol, LDL cholesterol levels were similar, but beta-VLDL cholesterol levels increased from 60 +/- 4 mg/dL (n = 10) to 550 +/- 75 mg/dL (n = 8; P < .0001). In Watanabe heritable hyperlipidemic (WHHL) rabbits, LDL cholesterol levels were 2.3-fold higher (n = 13; P < .0001) than in NZW rabbits on 0.5% cholesterol, whereas their beta-VLDL cholesterol levels were 3.7-fold lower (P < .0001), resulting in similar total cholesterol levels. At 2 months, mean intimal areas of lesions in the coronary arteries of NZW rabbits on 0.125% cholesterol were 0.13 +/- 0.045 mm2 (n = 4; mean +/- SEM) and were 5.8-fold, (n = 4; P = .016) and 2.0-fold (n = 6; P = NS versus 0.125% cholesterol and P = .014 versus 0.5% cholesterol) higher in NZW rabbits on 0.5% cholesterol and in WHHL rabbits, respectively. At 5 months, mean intimal areas were 0.47 +/- 0.088 mm2 (n = 6) in NZW rabbits on 0.125% cholesterol and were 4.5-fold (n = 4; P = .0001) and 2.0-fold (n = 7; P = .012 and P = .0019) higher in rabbits on 0.5% cholesterol and in WHHL rabbits, respectively. Levels of oxidized apoB-100 containing lipoproteins (both beta-VLDL and LDL) in the lesions correlated with mean intimal area (r = .88; n = 31; P < .0001) of those lesions and with the plasma levels of total beta-VLDL/LDL (r = .72; P < .0001). Levels of oxidized apoB-100 containing lipoproteins in the arterial wall correlate with progression of hypercholesterolemia-induced coronary atherosclerotic lesions. Plasma levels of beta-VLDL relative to similar increases in LDL result in a more pronounced accumulation of oxidized apoB-100 containing lipoproteins in the arterial wall and in the plasma and a more rapid progression of coronary atherosclerosis.     

The association of HincII/low density lipoprotein receptor (LDLR) restriction fragment length polymorphism (RFLP) with diabetes mellitus and its lipid phenotype with PCR gene amplification

The association of low density lipoprotein receptor (LDLR) gene HincII RFLP with diabetes mellitus and its lipid metabolism was studied in 196 Chinese with PCR gene amplification. 16 IDDM and 75 NIDDM were included. The most common genotype and allele frequencies of NIDDM were H2H2 (0.78) and H2 (0.89) respectively, and no significant differences were found in comparison with the normal control. The NIDDM with low LDL level (< 1.3 mmol/L) had less H2H2 type and H2 frequencies. Allele 1 (H1) was possibly related to the higher level of serum cholesterol, but allele 2 (H2) was quite the reverse. The phenotype of lipid metabolism was partially determined by the genotype. LDL, tc and tg level of NIDDM were significantly higher than the normal control (P < 0.001, 0.001, 0.05 respectively), indicating that NIDDM was accompanied by disturbance of lipid metabolism.