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Mo-P6:403 Enhanced APOB48 metabolism in lipoprotein lipase S447X carriers
Mon&ty, June 19, 2006: Poster Session P6 Genetics of cardiovascular disease
134
hydrophobic glycoprotein that catalyses the heterotransfer of cholesteryl esters and triacylglycerols among lipoproteins. Cholesteryl ester transfer protein (CETP) deficiency is one of the most important and common causes of hyperalphalipoproteinemia (HALP) and mutations in the CETP gene have been identified, mostly in the Japanese population. CETP deficiency is thought to be a state of impaired reverse cholesterol transport, which may possibly lead to the development of atherosderotic cardiovascular disease despite high HDL-cholesterol (HDL-C) levels. Thus, it is important to investigate whether HALP is caused by CETP deficiency. In order to define the prevalence of mutations of CETP in the Italian population we have studied a group of 23 subjects from Palermo and Padua areas with primary HALP (HDL-C > 80 mg/dl). For this reason we designed a screening strategy based on Southern Blot and hi-directional direct sequencing procedures to analyse the coding regions and the flanking intron sequences of the CETP gene. This strategy has allowed us to identify so far a novel nonsense mutation of CETP gene in two Sicilian probands, chaxacterized by a single base substitution ( C > T at nucleotide 674 in exon 6 resulting in Q165stop). In the two unrelated CETP deficient probands the CETP activity was undetectable with the standard fluorescent assay. This is, we believe, the first mutation in the CETP gene responsible for HALP reported in Italian patients. I
Mo-P6:401 [ A P O E G E N O T Y P E A N D A L L E L E D I S T R I B U T I O N IN A S A M P L E O F D Y S L I P I D A E M I C PATIENTS i
L.R. Ranganath, W. Taylor, J.L. Usher. Department of Cl#ucal
Biochemistry, Royal Liverpool Universi~ Hospital, Liverpool, United Kingdom Apolipoprotein E (ApoE) is a protein that plays a key role in the metabolism of cholesterol and triglyceride as a receptor binding ligand mediating the deaxance of VLDL cholesterol from plasma. ApoE is coded by a polymorphic gene locus with three common alleles epsilon2,3,and 4 and six genotypes, giving three protein isoforms with differing binding affinities and these axe assodated with variations in drculating lipid concentrations. Our object is to study the distribution of ApoE types in 222 subjects attending hospital for lipid profiles and to compare them with results from other general population studies. ApoE genotyping was performed by PCR amplification and mutation detection using fluorescent hybridization probes and melting peak analysis. Allele frequencies were estimated by a gene counting method and the results showed epsilon2 9%,e3 70% and e4 21%. When examining the influence of ApoE polymorphism on lipid profile, the E2 group included genotypes E2/E2 and E2/E3, the E4 group included E4/E4 and E3/E4 and the E3 group included only E3/E3 homozygotes. The mean total cholesterol values were E2:7.99, E3:7.85 and E4: 7.72mmol/L. The mean HDL values were E2: 1.15,E3:1.31 and E4: 1.28mmol/L. The presence of the epsilon2 allele was associated with lower HDL values. When comparing our ApoE allele frequencies to the distributions found in general populations,we observed double the epsilon4 allele frequency when compared to those in five W.European studies. This increase in the epsilon4 allele frequency in our dyslipidaemic subjects reflects its association with elevated cholesterol levels.
from white blood cells by the method of salt extraction. A SNP from the CETP gene was analyzed using PCR-ASO analysis. Polymorphisms of the CETP gene influence CETP activity and HDL cholesterol concentration and might agect the dyslipidemia and CAD incidence. Other evaluated risk factors were hypertension, diabetes, hip to waist ratio, smoking, physical activity, familial history of CAD, sudden death, hypertension, other vessel diseaseResuits:The mean value of total cholesterol was 6.3, HDL-0.8, triglycerides-1.08. 85% are with hypertensiom53%-with clinical evidence of heart faJlure,CAD31%.Preliminary results show an association of CETP SNPs and HDL and total cholesterolConclusions:There is a very high frequency of CAD, familial sudden death, hypertension and dyslipidemia in this small population. Possible reason is the consanguine marriage with a higher frequency of different polymorphisms, without monogenic lipid disorder. There is a possible relation of the polymorphisms in the CETP gene and the incidence of dyslipidemia in this population Funding: KRKA Pharmaceutical Company, Medical University, Pleven, Bulgaria
I Mo-P6:403 I E N H A N C E D
A P O B 4 8 M E T A B O L I S M IN LIPOPROTEIN LIPASE $447X CARRIERS
M.C. Nierman ] , J. Rip 2 , J.A. Kuivenhoven 2 , N. Sakad 3 , J.J.E Kastelein ] , M.G.M. De Sain-Van Der Velden 4, E.S.G. Stroes ] , B.H. Prinsen 4.
1Department of Vascular Medicine, Academic Medical Center; University of Amsterdam, Amsterdam, The Netherlands: 2Department of Eaperimental Vascular Medicbte, Academic Medical Center; Universi~ of Amsterdam, Amsterdam, The Netherlands." ~Department of lrtterTtal Medicine arm Molecular Science, Osaka Universi~ Graduate School of Medicirte, Osaka, Japan." 4Department of Metabolic arid Endocrine Diseases, Universi~ Medical Center; Utrecht, The Netherlands Objective: Carriers of the frequent lipoprotein lipase (LPL) variant $447X are characterized by enhanced conversion of TRL apoB100. Here, we set out to investigate whether this LPL variant is also associated with enhanced chylomicron conversion. Therefore, we evaluated apoB48 kinetics in homozygous LPLS447X carriers in the fed state by infusion of isotope L-[1J3C]-valine and subsequent compartmental modeling. M e t h o d s : Chylomicron metabolism was assessed in five homozygous LPLS447X carriers and five controls. Subjects were continuously fed and received infusion of stable isotope L-[1- 13C]-valine. Results were analyzed by S A A M I I modeling. Results: Fasting (2.4-fold, p=0.02) as well as non-fasting (1.6-fold, p=0.051) apoB48 concentration was increased in carriers compared to controls. In addition, caxriers exhibited a 1.7-fold higher apoB48 poolsize (p=0.04). Interestingly, apoB48 fractional catabolic rate was 1.9-fold higher (p=0.007) and apoB48 synthesis was more than 2-fold higher (p=0.006) in caxriers compared to controls. C o n d u s i o n : In the present study, we show that caxriers of the frequent LPLS447X variant exhibit enhanced apoB48 conversion. Previously, homozygous LPLS447X carriers were also shown to present with enhanced apoB100 TRL conversion. Combined, this LPLS447X gain of function variant positively affects apoB48 as well as apoB100 TRL metabolism. Further studies are warranted to investigate whether these effects underlie the cardiovascular protection associated with the LPLS447X variant. Funding: None.
Mo-P6:404 Mo-P6:402
CHOLESTEROL ESTER TRANSFER PROTEIN (CETP) POLYMORPHISM AND MILD D Y S L I P I D E M I A IN A C L O S E D P O P U L A T I O N a 3 . / Medical Universi~, S. Tisheva 1 , A. Neykova 1, R. Komsa-, N. I=natov
Cardiology Clinic, Pleven, Bulgaria." 2Medical Universi~, Biochemistry Department, Pleven, Bulgaria." ~Regional Hospital, Cardiology Department, Teteven, Bulgaria Objectives: The aim of our study was 1.to assess the polymorphic variants frequencies of CETP in a small population with mild dyslipidemia. All the population is about 10 000 people. This is almost closed community bulgarians, frequently with consanguine marriage (due to its religion-Muslims in Christian country). 2. Study objective: evaluate selected single nucleotide polymorphism (SNP) gene as predictors of laboratory phenotype and clinical (coronary artery disease-(CAD)) phenotypeMethods:We studied the risk factors for CAD in 200 patients with dislipidemia. We determined total cholesterol, HDL cholesterol, triglycerides. A genomic DNA was extracted
FAMILIAL DEFECTIVE APOLIPOPROTEIN GREECE
B100 IN
E. Koniari, E. LaJos, E. Drogaxi. Ixtboratoryfor Metabolic Disease,
Choremio Researeh btstitute, Universi~ of Athens, Aghia Sophia Children's Hospital, Athens, Greece Objective: Familial defective apolipoprotein B-100 (FDB) is an autosomal dominant form of monogenic familial hypercholesterolemia (FH). Three mutations in the apolipoprotein B-100 (ApoB) gene are known to reduce the binding affinity of the low density lipoprotein (LDL) particle for the LDL receptor. The most common mutation in the is R3500Q. More infrequent mutations axe R3500W and R3531C. ApoB mutations have not been found in Finland, Israel, and Japan. Our objective is to determine the presence of ApoB mutations in Greece. M e t h o d s : 347 individuals (154 families) with moderately or severely elevated plasma cholesterol were recruited from January 2004 through October 2005. 69 children were diagnosed as having FH based on clinical and biochemical criteria (total cholesterol >200 mg/dL, normal triglyceride levels).
XIV bzterTtational Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006
134
hydrophobic glycoprotein that catalyses the heterotransfer of cholesteryl esters and triacylglycerols among lipoproteins. Cholesteryl ester transfer protein (CETP) deficiency is one of the most important and common causes of hyperalphalipoproteinemia (HALP) and mutations in the CETP gene have been identified, mostly in the Japanese population. CETP deficiency is thought to be a state of impaired reverse cholesterol transport, which may possibly lead to the development of atherosderotic cardiovascular disease despite high HDL-cholesterol (HDL-C) levels. Thus, it is important to investigate whether HALP is caused by CETP deficiency. In order to define the prevalence of mutations of CETP in the Italian population we have studied a group of 23 subjects from Palermo and Padua areas with primary HALP (HDL-C > 80 mg/dl). For this reason we designed a screening strategy based on Southern Blot and hi-directional direct sequencing procedures to analyse the coding regions and the flanking intron sequences of the CETP gene. This strategy has allowed us to identify so far a novel nonsense mutation of CETP gene in two Sicilian probands, chaxacterized by a single base substitution ( C > T at nucleotide 674 in exon 6 resulting in Q165stop). In the two unrelated CETP deficient probands the CETP activity was undetectable with the standard fluorescent assay. This is, we believe, the first mutation in the CETP gene responsible for HALP reported in Italian patients. I
Mo-P6:401 [ A P O E G E N O T Y P E A N D A L L E L E D I S T R I B U T I O N IN A S A M P L E O F D Y S L I P I D A E M I C PATIENTS i
L.R. Ranganath, W. Taylor, J.L. Usher. Department of Cl#ucal
Biochemistry, Royal Liverpool Universi~ Hospital, Liverpool, United Kingdom Apolipoprotein E (ApoE) is a protein that plays a key role in the metabolism of cholesterol and triglyceride as a receptor binding ligand mediating the deaxance of VLDL cholesterol from plasma. ApoE is coded by a polymorphic gene locus with three common alleles epsilon2,3,and 4 and six genotypes, giving three protein isoforms with differing binding affinities and these axe assodated with variations in drculating lipid concentrations. Our object is to study the distribution of ApoE types in 222 subjects attending hospital for lipid profiles and to compare them with results from other general population studies. ApoE genotyping was performed by PCR amplification and mutation detection using fluorescent hybridization probes and melting peak analysis. Allele frequencies were estimated by a gene counting method and the results showed epsilon2 9%,e3 70% and e4 21%. When examining the influence of ApoE polymorphism on lipid profile, the E2 group included genotypes E2/E2 and E2/E3, the E4 group included E4/E4 and E3/E4 and the E3 group included only E3/E3 homozygotes. The mean total cholesterol values were E2:7.99, E3:7.85 and E4: 7.72mmol/L. The mean HDL values were E2: 1.15,E3:1.31 and E4: 1.28mmol/L. The presence of the epsilon2 allele was associated with lower HDL values. When comparing our ApoE allele frequencies to the distributions found in general populations,we observed double the epsilon4 allele frequency when compared to those in five W.European studies. This increase in the epsilon4 allele frequency in our dyslipidaemic subjects reflects its association with elevated cholesterol levels.
from white blood cells by the method of salt extraction. A SNP from the CETP gene was analyzed using PCR-ASO analysis. Polymorphisms of the CETP gene influence CETP activity and HDL cholesterol concentration and might agect the dyslipidemia and CAD incidence. Other evaluated risk factors were hypertension, diabetes, hip to waist ratio, smoking, physical activity, familial history of CAD, sudden death, hypertension, other vessel diseaseResuits:The mean value of total cholesterol was 6.3, HDL-0.8, triglycerides-1.08. 85% are with hypertensiom53%-with clinical evidence of heart faJlure,CAD31%.Preliminary results show an association of CETP SNPs and HDL and total cholesterolConclusions:There is a very high frequency of CAD, familial sudden death, hypertension and dyslipidemia in this small population. Possible reason is the consanguine marriage with a higher frequency of different polymorphisms, without monogenic lipid disorder. There is a possible relation of the polymorphisms in the CETP gene and the incidence of dyslipidemia in this population Funding: KRKA Pharmaceutical Company, Medical University, Pleven, Bulgaria
I Mo-P6:403 I E N H A N C E D
A P O B 4 8 M E T A B O L I S M IN LIPOPROTEIN LIPASE $447X CARRIERS
M.C. Nierman ] , J. Rip 2 , J.A. Kuivenhoven 2 , N. Sakad 3 , J.J.E Kastelein ] , M.G.M. De Sain-Van Der Velden 4, E.S.G. Stroes ] , B.H. Prinsen 4.
1Department of Vascular Medicine, Academic Medical Center; University of Amsterdam, Amsterdam, The Netherlands: 2Department of Eaperimental Vascular Medicbte, Academic Medical Center; Universi~ of Amsterdam, Amsterdam, The Netherlands." ~Department of lrtterTtal Medicine arm Molecular Science, Osaka Universi~ Graduate School of Medicirte, Osaka, Japan." 4Department of Metabolic arid Endocrine Diseases, Universi~ Medical Center; Utrecht, The Netherlands Objective: Carriers of the frequent lipoprotein lipase (LPL) variant $447X are characterized by enhanced conversion of TRL apoB100. Here, we set out to investigate whether this LPL variant is also associated with enhanced chylomicron conversion. Therefore, we evaluated apoB48 kinetics in homozygous LPLS447X carriers in the fed state by infusion of isotope L-[1J3C]-valine and subsequent compartmental modeling. M e t h o d s : Chylomicron metabolism was assessed in five homozygous LPLS447X carriers and five controls. Subjects were continuously fed and received infusion of stable isotope L-[1- 13C]-valine. Results were analyzed by S A A M I I modeling. Results: Fasting (2.4-fold, p=0.02) as well as non-fasting (1.6-fold, p=0.051) apoB48 concentration was increased in carriers compared to controls. In addition, caxriers exhibited a 1.7-fold higher apoB48 poolsize (p=0.04). Interestingly, apoB48 fractional catabolic rate was 1.9-fold higher (p=0.007) and apoB48 synthesis was more than 2-fold higher (p=0.006) in caxriers compared to controls. C o n d u s i o n : In the present study, we show that caxriers of the frequent LPLS447X variant exhibit enhanced apoB48 conversion. Previously, homozygous LPLS447X carriers were also shown to present with enhanced apoB100 TRL conversion. Combined, this LPLS447X gain of function variant positively affects apoB48 as well as apoB100 TRL metabolism. Further studies are warranted to investigate whether these effects underlie the cardiovascular protection associated with the LPLS447X variant. Funding: None.
Mo-P6:404 Mo-P6:402
CHOLESTEROL ESTER TRANSFER PROTEIN (CETP) POLYMORPHISM AND MILD D Y S L I P I D E M I A IN A C L O S E D P O P U L A T I O N a 3 . / Medical Universi~, S. Tisheva 1 , A. Neykova 1, R. Komsa-, N. I=natov
Cardiology Clinic, Pleven, Bulgaria." 2Medical Universi~, Biochemistry Department, Pleven, Bulgaria." ~Regional Hospital, Cardiology Department, Teteven, Bulgaria Objectives: The aim of our study was 1.to assess the polymorphic variants frequencies of CETP in a small population with mild dyslipidemia. All the population is about 10 000 people. This is almost closed community bulgarians, frequently with consanguine marriage (due to its religion-Muslims in Christian country). 2. Study objective: evaluate selected single nucleotide polymorphism (SNP) gene as predictors of laboratory phenotype and clinical (coronary artery disease-(CAD)) phenotypeMethods:We studied the risk factors for CAD in 200 patients with dislipidemia. We determined total cholesterol, HDL cholesterol, triglycerides. A genomic DNA was extracted
FAMILIAL DEFECTIVE APOLIPOPROTEIN GREECE
B100 IN
E. Koniari, E. LaJos, E. Drogaxi. Ixtboratoryfor Metabolic Disease,
Choremio Researeh btstitute, Universi~ of Athens, Aghia Sophia Children's Hospital, Athens, Greece Objective: Familial defective apolipoprotein B-100 (FDB) is an autosomal dominant form of monogenic familial hypercholesterolemia (FH). Three mutations in the apolipoprotein B-100 (ApoB) gene are known to reduce the binding affinity of the low density lipoprotein (LDL) particle for the LDL receptor. The most common mutation in the is R3500Q. More infrequent mutations axe R3500W and R3531C. ApoB mutations have not been found in Finland, Israel, and Japan. Our objective is to determine the presence of ApoB mutations in Greece. M e t h o d s : 347 individuals (154 families) with moderately or severely elevated plasma cholesterol were recruited from January 2004 through October 2005. 69 children were diagnosed as having FH based on clinical and biochemical criteria (total cholesterol >200 mg/dL, normal triglyceride levels).
XIV bzterTtational Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006