Biomedical subjects

J A Hubácek

Publications and source records attributed to J A Hubácek.

At least 19 recordsLinked to original sources

PubMed2005

Apolipoprotein A5 and hypertriglyceridemia in Prague hypertriglyceridemic rats.

High plasma triglyceride (TG) level is a major independent risk factor of coronary heart disease. A newly identified Apolipoprotein A5 (Apoa5) gene has been shown to play an important role in determining plasma TG concentrations in humans and mice. Prague hereditary hypertriglyceridemic (HTG) rats are a useful model of human hypertriglyceridemia and other symptoms of metabolic syndrome. Thus, the variation of Apoa5 gene and its expression were studied in this strain under normal conditions and after chronic fructose loading. Lewis and Wistar rats served as normotriglyceridemic controls. Plasma TG were significantly higher in HTG rats in comparison with both control strains. Screening of the coding regions and intron-exon boundaries of Apoa5 gene did not reveal any mutation of this gene in HTG rats in comparison with Lewis and Wistar ones. However, rat Apoa5 gene contains only one intron in contrast with two introns of mouse Apoa5 gene. Under the basal conditions the expression of Apoa5 was lower in all age groups of HTG rats compared to Wistar animals. Furthermore, during chronic fructose loading there were no significant changes of Apoa5 expression in HTG rats, although plasma TG levels rose 3-4 times within first two days of fructose loading and were increased during the whole period of fructose treatment. In conclusion, Apoa5 does not seem to be a genetic determinant of hypertriglyceridemia in HTG rats. The absence of significant changes in Apoa5 gene expression during chronic fructose-induced TG elevation excludes its major role in mechanisms compensating severe hypertriglyceridemia.

Animals↗

PubMed2005

Apolipoprotein AV variants do not affect C-reactive protein levels in Caucasian males.

The important role of APOAV gene variants in determination of plasma triglyceride levels has been shown in many population studies. Recently, an influence of APOAV T-1131>C polymorphism on C-reactive protein (CRP) in young Korean males has been reported. We have therefore analyzed a putative association between T-1131>C, Ser19>Trp and Val153>Met APOAV variants (PCR and restriction analysis) and CRP concentrations in 1119 Caucasian males, aged between 28 and 67 years (49.2+/-10.8 years). The frequency of C allele carriers was lower in Caucasians than in Koreans (15.5% vs. 46.2%). CRP levels did not differ between T/T homozygotes (n=946, 1.61+/-2.05 mg/l) and carriers of the C allele (n=173, 1.67+/-1.95 mg/l). Thus, in contrast to Korean males, T-1131>C APOAV variant has no effect on plasma concentrations of CRP in a large group of Caucasian males. Other APOAV variants (Ser19>Trp and Val153>Met) did not also influence plasma concentrations of CRP. APOAV variants are unlikely to be an important genetic determinant of plasma CRP concentrations in Caucasian males.

Adult↗

PubMed2005

Rare variant of apolipoprotein E (Arg136 -->Ser) in two normolipidemic individuals.

Through the analysis of the common apolipoprotein (apo) E gene polymorphism in large Caucasian population study with the PCR and subsequent restriction analysis, we have identified carriers of mutant allele Arg136-->Ser. Both of them (71-years-old female and her 43-years-old son) have normal lipid parameters. We suggest that Arg136-->Ser mutation in apoE is not necessarily connected with elevated lipid levels in all cases. Furthermore, so far unidentified factors (environmental and/or genetic) are important for the development of lipid metabolism disorders in apoE Arg136-->Ser mutation carriers.

Adult↗

PubMed2005

[Genetic determinants of osteoporosis].

Osteoporosis is a chronic progressive disease, characterized by higher bone resorption than bone mass accumulation. This leads to reduction of the bone mass, to microarchitectural deterioration of the bone tissue and to the increased risk of bone fracture. Osteoporosis affects predominately postmenopausal females, but it is also diagnosed at elderly males. Although osteoporosis is influenced by various environmental factors (mainly by dietary habits and physical activity), analysis of results obtained from studies with different designs (population-, family-, association- studies) confirmed, that risk of osteoporosis development and risk of osteoporotic fractures are significantly influenced by genetic predispositions. The genetic determination of osteoporosis is not yet completely understood. However, it is clear, that although there are mutations in some genes causing rare form of osteoporosis, osteoporosis is a polygenic disease--it is influenced by common variants (polymorphisms) of several different genes. For example genes for vitamin D receptor, estrogen receptor alpha, collagen type I alpha1, transforming growth factor beta-1 and some others are indicated to play a role in genetic determination of osteoporosis. In this review we summarize our recent knowledge about the genetic determination of osteoporosis.

Female↗

PubMed2004

The influence of G-protein beta3-subunit gene and endothelial nitric oxide synthase gene in exon 7 polymorphisms on progression of autosomal dominant polycystic kidney disease.

BACKGROUND: A significant phenotypical variability is observed in autosomal dominant polycystic kidney disease (ADPKD). The variability cannot be fully explained by the genetic heterogeneity of the disease. We examined the influence of G-protein beta3-subunit C825T polymorphism and endothelial nitric oxide synthase Glu298Asp polymorphism on the progression of ADPKD towards end stage renal failure (ESRF). METHODS: 306 ADPKD patients (pts) were analyzed; 261 pts (136 males, 125 females) with ESRF, with subgroup of 73 pts (44 males, 29 females) with ESRF before 45 years (rapid progressors), 46 pts (20 males, 26 females) with ESRF later than in 63 years (slow progressors) and 45 ADPKD pts (17 males, 28 females) in mean age 51 years with serum creatinine under 110 micromol/L (slow progressors) and 100 genetically unrelated healthy Czech subjects. DNA samples from collected blood were genotyped for G-protein beta3-subunit C825T genotype in exon 10 and for endothelial nitric oxide synthase Glu298Asp genotype in exon 7. RESULTS: The G-protein beta3-subunit C825T genotype exhibited no significant differences among the groups of slow progressors (6.6% (6/91) TT, 54.9% (50/91) CT, 38.8% (35/91) CC), rapid progressors (9.6% (7/73) TT, 46.6% (34/73) CT, 43.8% (32/73) CC), ADPKD group with ESRF between 40-63 years (9.2% (13/142) TT, 50% (71/142) CT, 40.8% (58/142) CC) and control group (12% TT, 44% CT, 44% CC). When comparing the ages of ESRF of all patients with ESRF, we did not find significant differences in the ages: males TT--51.7+/-8.8 years, CT--51.9+/-10.3 years, CC--49.7+/-10.2 years and females TT--56+/-9.9 years, CT--53.2+/-8.5 years, CC--53.9+/-8.7 years. The endothelial nitric oxide synthase Glu298Asp and Asp29Asp genotypes were significantly more frequent in rapid progressors (9.6% (7/73) Asp/Asp, 39.7% (29/73) Asp/Glu, 50.7% (37/73) Glu/Glu) and in ADPKD group with ESRF between 40-63 years (11.3% (16/142) Asp/Asp, 41.5% (59/142) Asp/Glu, 47.2% (67/142) Glu/Glu) in comparison with slow progressors (8.8% (8/91) Asp/Asp, 24.2% (22/91) Asp/Glu, 67.0% (61/91) Glu/Glu) and with control group (8% Asp/Asp, 32% Asp/Glu, 60% Glu/Glu) (Chi-square test, p<0.05). Comparing the ages of ESRF of all patients with ESRF, we did not find significant differences in the ages in males with Asp/Asp--54.9+/-10.4 years, Asp/Glu--50.2+/-9.4 years, Glu/Glu--51.0+/-10.4 years. We found out in homozygous Asp/Asp females significantly earlier onset of ESRF (49.2+/-5.6 years) in comparison with heterozygous females (53.3+/-7.2 years) and with Glu/Glu homozygous females (54.8+/-9.7 years) (t-test, p<0.05). CONCLUSION: We excluded the significance of G-protein beta3-subunit C825T polymorphism on the progression of ADPKD. We established the negative prognostic value of the carriers of Asp variant of eNOS polymorphism. Finding of new modifiers could have in future clinical consequences for ADPKD patients.

Adult↗

PubMed2004

New variants in the apolipoprotein AV gene in individuals with extreme triglyceride levels.

Animal studies (on transgenic and knock-out mice) and human association analysis assessed the importance of APOAV gene for plasma triglyceride determination. New APOAV missense variants (Val153 --> Met and Cys185 --> Gly) have been detected recently. We have analyzed these variants in 83 unrelated patients with extreme lipid parameters (triglycerides of 20.4+/-2.8 mmol/l and total cholesterol of 10.4+/-3.7 mmol/l) and in a control population group consisting of 2,559 unrelated Caucasians. In patients, the frequency of the Met153 carriers was slightly but not significantly higher (9.64 % vs. 6.49 %) compared to the population sample. This suggested that Val153 Met polymorphism in the APOAV gene does not represent an important risk factor for developing the extreme levels of plasma triglycerides. We did not detect carriers of the Gly185 allele among patients or 420 healthy individuals. We suppose that this variant is probably not present in Caucasian populations

Adult↗

PubMed2004

[Antagonistic effect of the insertion/deletion (HpaI) polymorphism in the regulatory part of the gene for apolipoprotein CI in children with high and low levels of cholesterol].

BACKGROUND: High plasma lipids are one of the risk factor of atherosclerosis. Both environmental (diet, physic activity) and genetic factors have been implicated in the development of hyperlipidaemia. Apolipoprotein (apo) CI plays an important role in plasma cholesterol and triglycerides transport by VLDL particles. The aim of the study was to establish the role of the insertion/deletion polymorphism in apoCI gene in the determination of plasma lipids in children. METHODS AND RESULTS: Using PCR and restriction analysis (HpaI) we have measured I/D polymorphism in APOCI gene in two groups of children selected from opposite ends of the cholesterol distribution curve of 2000 children. Eighty-two children in high-(HCG) and eighty-six children in low-(LCG) cholesterolemic groups participated on the study. No significant difference was found in the frequencies of the APOCI genotypes or alleles between HCG vs. LCG. Association between LDL cholesterol and genotypes within the LCG was found--the D/D homozygotes have higher lipid level compared to the others (p < 0.05). In LCG opposite, but insignificant (p = 0.09) trend was observed. CONCLUSIONS: The widespread I/D polymorphism in the gene for APOCI determines the plasma lipid levels in childhood and it could become another important genetic marker that plays a role in the genetic determination of cholesterolemia.

Apolipoprotein C-I↗

PubMed2004

ATP-binding cassette (ABC) transporters in human metabolism and diseases.

The ATP-binding cassette (ABC) superfamily of active transporters involves a large number of functionally diverse transmembrane proteins. They transport a variety of substrates including amino acids, lipids, inorganic ions, peptides, saccharides, metals, drugs, and proteins. The ABC transporters not only move a variety of substrates into and out of the cell, but also are also involved in intracellular compartmental transport. Energy derived from the hydrolysis of ATP is used to transport the substrate across the membrane against a concentration gradient. The typical ABC transporter consists of two transmembrane domains and two nucleotide-binding domains. Defects in 14 of these transporters cause 13 genetic diseases (cystic fibrosis, Stargardt disease, adrenoleukodystrophy, Tangier disease, etc.). Mutations in three genes affect lipid levels expressively. Mutations in ABCA1 cause severe HDL deficiency syndromes called Tangier disease and familial high-density lipoprotein deficiency, which are characterized by a severe deficiency or absence of high-density lipoprotein in the plasma. Two other ABCG transporters, ABCG5 and ABCG8, mutations of which cause sitosterolemia, have been identified. The affected individuals absorb and retain plant sterols, as well as shellfish sterols.

ATP-Binding Cassette Transporters↗

PubMed2004

Polymorphisms in ABCG5 and ABCG8 transporters and plasma cholesterol levels.

ABCG5 and ABCG8 transporters play an important role in the absorption and excretion of sterols. Missence polymorphisms (Gln604Glu in the ABCG5 and Asp19His, Tyr54Cys, Thr400Lys, and Ala632Val in the ABCG8) in these genes have been described. In 131 males and 154 females whose dietary composition markedly changed and lipid parameters decreased over an 8-year follow-up study (total cholesterol decreased from 6.21+/-1.31 mmol/l in 1988 to 5.43+/-1.06 mmol/l in 1996), these polymorphisms were investigated using PCR. Plasma lipid levels and changes in plasma lipid levels were independent of the Gln604Glu polymorphism in ABCG5 and Asp19His and the Ala632Val polymorphisms in ABCG8. The Tyr54Cys polymorphism influenced the degree of reduction in total plasma cholesterol (delta -0.49 mmol/l in Tyr54 homozygotes vs. delta +0.12 mmol/l in Cys54 homozygotes, p<0.04) and LDL-cholesterol (delta -0.57 mmol/l in Tyr54 homozygotes vs. delta +0.04 mmol/l in Cys54 homozygotes, p<0.03) levels between 1988 and 1996 in females, but not in males. Male Thr400 homozygotes exhibited a greater decrease in total cholesterol (delta -0.90 mmol/l vs. delta -0.30 mmol/l, p<0.02) and LDL-cholesterol (delta -0.62 mmol/l vs. delta -0.19 mmol/l, p<0.04) than Lys400 carriers. No such association was observed in females. We conclude that Tyr54Cys and Thr400Lys variations in the ABCG8 gene may play a role in the genetic determination of plasma cholesterol levels and could possibly influence the gender-specific response of plasma cholesterol levels after dietary changes. These polymorphisms are of potential interest as genetic variants that may influence the lipid profile.

ATP Binding Cassette Transporter, Subfamily G, Mem↗

PubMed2004

The A-204C polymorphism in the cholesterol 7alpha-hydroxylase (CYP7A1) gene determines the cholesterolemia responsiveness to a high-fat diet.

The aim of the study was to ascertain whether the A-204C polymorphism in the cholesterol 7 -hydroxylase (CYP7A1) gene plays any role in determining LDL-cholesterol (LDL-C) concentration responsiveness to a high-fat diet. The concentrations of total cholesterol and LDL-cholesterol were measured in eleven healthy men (age: 30.9+/-3.2 years; BMI: 24.9+/-2.7 kg/m(2);;) who were homozygous for either the -204A or -204C allele, after 3 weeks on a low-fat (LF) diet and 3 weeks on a high-fat (HF) diet. During both dietary regimens, the isocaloric amount of food was provided to volunteers; LF diet contained 22 % of energy as a fat and 2.2 mg of cholesterol/kg of body weight a day, HF diet 40 % of fat and 9.7 mg of cholesterol/kg of body weight a day. In six subjects homozygous for the -204C allele, the concentrations of cholesterol and LDL-cholesterol were significantly higher on HF than on LF diet (cholesterol: 4.62 vs. 4.00 mmol/l, p<0.05; LDL-C: 2.15 vs. 1.63 mmol/l, p<0.01, respectively); no significant change was observed in five subjects homozygous for the -204A allele. There were no other differences in lipid and lipoprotein-lipid concentrations. Therefore, the polymorphism in the cholesterol 7alpha-hydroxylase promotor region seems to be involved in the determination of cholesterol and LDL-C responsiveness to a dietary fat challenge.

Adult↗

PubMed2004

[Apolipoprotein AV and triglyceridemia].

High plasma triglyceride levels have been suggested to be independent risk factors of cardiovascular disease development and cardiovascular diseases are the most common cause of death in industrial countries around the world. It is known, that plasma levels of triglycerides are partially genetically determined. The importance of apoAV gene for determination of plasma triglyceride levels has been suggested by creations of transgenic and knock-out mice and confirmed on population studies. More then ten variants have been described in the human apoAV gene. Associations between four of them (T-1131-->C, Serl19-->Trp, Val153-->Met a Cys185-->Gly) and plasma triglyceride levels have been intensively analysed in different populations. Although with some differences between ethnic groups, alleles C-1131, Trp19 a Cys185 (so far detected just in Chinese population) are connected with elevated levels of plasma triglycerides. First analysis have detected that T-11131-->C a Ser19-->Trp apoAV variants could influence risk of myocardial infarction and size of LDL particles. Val153-->Met polymorphism is not associated with plasma levels of triglycerides, but females homozygous for Val153 have elevated levels of plasma HDL cholesterol.

Animals↗

PubMed2003

Apolipoprotein E and apolipoprotein CI polymorphisms in the Czech population: almost complete linkage disequilibrium of the less frequent alleles of both polymorphisms.

Apolipoproteins E and CI are the predominant components of triglyceride-rich lipoproteins. The genes are located in one gene cluster and both are polymorphic. Three allelic (epsilon2, epsilon3 and epsilon4) polymorphisms of the APOE gene influence plasma cholesterol levels. The distribution of these alleles differ between ethnic groups. PCR genotyping was used to determine the APOE and APOCI allele incidence in a representative group of 653 probands (302 men and 351 women) of Czech origin. The observed relative frequencies for the epsilon2, epsilon3 and epsilon4 alleles were 7.1 %, 82.0 % and 10.9 %, respectively, and are similar to other middle European populations. APO epsilon4 carriers have the highest and APO epsilon2 carriers the lowest levels of plasma total cholesterol (p<0.0001) and LDL cholesterol (p<0.0001). The frequency of the insertion (I) allele (HpaI restriction site present) of the APOCI polymorphism was 18.5 %. APOCI I/I homozygotes have the highest level of triglycerides (p<0.003). An almost complete linkage disequilibrium of the insertion allele of APOCI with the APOE alleles epsilon2 and epsilon4 has been detected and suggests that the deletion in the APOCI gene probably follows the deriving of all three APOE alleles on the APO epsilon3 allele background.

Apolipoprotein C-I↗

PubMed2003

[CD14 (C-159-->T) polymorphism and levels of C-reactive protein].

BACKGROUND: High plasma levels of C-reactive protein (involved in unspecific host defence) have been described as independent risk factor of atherosclerosis. The possible association has been analysed between the CD14C-159-->T polymorphism and plasma level of CRP. METHODS AND RESULTS: With the PCR and subsequent restriction analysis we have evaluated C-159-->T polymorphism in the CD14 gene of 166 representatively selected male Caucasians with known plasma level of CRP. The CRP was measured immunologically. A significantly higher (p < 0.01) frequency of the CD14-159TT homozygotes between the individuals with the plasma level of CRP > 2.19 mg/l (31.9%, 15 out of 47) has been detected when compared to the group with plasma level of CRP lower than 2.18 mg/l (11.9%, 5 out of 42). CONCLUSIONS: CD14 C-159-->T polymorphism could be the first described genetic marker associated with plasma level of C-reactive protein.

Adult↗

PubMed2003

[Polymorphism in the regulatory part of the cholesterol 7 alpha hydroxylase gene in children with high and low levels of cholesterol].

BACKGROUND: High plasma cholesterol is one of the risk factors of atherosclerosis. Both environmental (diet, physic activity) and genetic factors have been concerned in the development of hypercholesterolemia. Cholesterol 7 alpha hydroxylase (CYP-7A1) is a key enzyme in the bile acid synthesis and it plays an important role in cholesterol catabolism. The aim of the study was to establish the role of A-204-->C polymorphism in CYP-7A1 gene in plasma lipid determination in children. METHODS AND RESULTS: Using PCR and restriction analysis (BsaI) we have measured A-204-->C polymorphism in CYP-7A1 gene in two groups of children selected from opposite ends of the cholesterol distribution curve of 2000 children. Eighty-two children in high- (HCG) and eighty-six children in low- (LCG) cholesterolemic groups participated in the study. No significant difference was found in the frequencies of the genotypes or alleles of the A-204-->C polymorphism in the CYP-7A1 gene between HCG and LCG. In HCG, C/C-204 homozygotes have the highest and A/A homozygotes the lowest levels of LDL-cholesterol (4.21 +/- 0.68 mmol/l vers. 3.69 +/- 0.60 mmol/l, p < 0.05). No associations between lipid parameters and genotypes within the LCG group were found. CONCLUSIONS: The A-204-->C polymorphism in the gene for CYP-7A1 is not the major determinant of plasma lipid levels in childhood. Its impact is expressed only on high cholesterol background.

Child↗

PubMed2001

[Plasma level of Lp(a) in patients with myocardial infarct is not controlled by the apolipoprotein E gene polymorphism].

BACKGROUND: We evaluated a two risk factors of atherosclerosis development, apolipoprotein E genotype and plasma level of Lp(a), and their association in Czech population. PATIENTS AND CONTROLS: Apo E and Lp(a) have been determined in the group of 109 men with premature myocardial infarction and compared with the population samples (301 men for apo E polymorphism and 112 men for Lp(a) evaluation). METHODS AND RESULTS: Apo E gene polymorphism was analysed by PCR with subsequent restriction analysis of the PCR product. Lp(a) concentration was measured enzymatically using the IMMUNO set. The frequency of alleles of apo E genotype in myocardial infarction patients did not significantly differ from that found in the control group. The distribution of the Lp(a) concentrations in MI patients was shifted to higher levels than in population sample (p < 0.0001). CONCLUSIONS: We have not found correlation between this two risk factors of myocardial infarction. High concentration of Lp(a) is on apo E polymorphism independent risk factor of development of myocardial infarction.

Adult↗

PubMed2001

[Polymorphisms in genes for cholesterol ester transfer protein, apolipoprotein C-III and lipoprotein lipase in children with high and low cholesterol levels] ].

BACKGROUND: High plasma lipids are one of the risk factor of atherosclerosis. The contribution of environmental and genetic factors to plasma lipids is roughly equal. Cholesterol ester transfer protein (CETP), lipoprotein lipase (LPL) and apolipoprotein (apo) CIII play an important role in plasma lipid metabolism. The aim of the study was to establish the role of polymorphisms in these genes in plasma lipid determination. METHODS AND RESULTS: Using PCR and restriction analysis we have measured Taq1 polymorphism in CETP, asparagine 291/serine polymorphism in LPL and C3238G polymorphism in apo CIII genes in two groups of children selected from opposite ends of the cholesterol distribution curve of 2000 children. 82 children in high- (HCG) and 86 in low- (LCG) cholesterol group participated in the study. No significant difference was found in the frequencies of the CETP and apo CIII genotypes between LCG and HCG. In the LCG, significantly more carriers (p < 0.05) of the LPL serine291 allele were found. CONCLUSIONS: Common polymorphisms in the CETP and apo CIII genes do not determine the plasma lipid levels in childhood. The carriers of the rare allele in the LPL gene could be genetically predisposed to low plasma lipid levels.

Alleles↗

PubMed2001

ACE gene polymorphism and long-term renal graft function.

OBJECTIVES: The long-term outcome of transplanted kidneys has not changed substantially and only a minority of grafts survives more than 15 yr. The aim of this study was to determine the influence of ACE gene polymorphism on long-term outcome after renal transplantation. DESIGN AND METHODS: Using PCR, we evaluated ACE I/D gene polymorphism in a group of patients with long-term graft function (LTF) over 15 yr and compared it with control groups of transplant recipients and population sample. RESULTS: The distribution of genotypes in the LTF group differed from transplant controls (p < 0.05). Moreover, DD homozygotes in the LTF group had better creatinine clearance (DD: 1.1 +/- 0.3, ID: 0.96 +/- 0.3, II: 0.76 +/- 0.3 mL/s; p < 0.05). There were no differences in genotype distribution between transplant and population samples. CONCLUSIONS: Results of our study have demonstrated a possible connection between the DD variant of ACE I/D gene polymorphism and excellent long-term graft function.

Adult↗

PubMed2001

Polymorphisms in the lipoprotein lipase and hepatic lipase genes and plasma lipid values in the Czech population.

We have determined the genotypes of two common polymorphisms in the lipoprotein lipase (S447X) and hepatic lipase (-480C/T) genes in a cohort of 285 representative selected Czech probands (131 male and 154 female), examined in 1988 and reinvestigated in 1996. The genotype distributions of both polymorphisms were in Hardy-Weinberg equilibrium and did not differ between male and female subjects. The rare allele frequency of the lipoprotein lipase polymorphism did not differ significantly from the other European populations. Compared to the German populations, the frequency of the hepatic lipase -480T allele was significantly higher in the Czech group (20% vs. 36%, p<0.0001). There were no significant associations between the lipoprotein lipase gene variants and lipid parameters measured either in 1988, or in 1996 or with changes of lipid parameters over the 8-year period. The carriers of the T-480 allele of the hepatic lipase polymorphism were found to have higher HDL cholesterol levels (p=0.02). However, this difference was confined to female subjects only. The male carriers of the -480T allele had higher concentrations of total cholesterol (p=0.03) as compared to CC-480 subjects. Both associations were observed in 1996 only. In the Slavic Czech population, a common polymorphism in the hepatic lipase gene (-480C/T), but not in the lipoprotein lipase gene (S447X), is a significant determinant of plasma HDL cholesterol in females and plasma total cholesterol in males and indicates the importance of gender-associated effects in the genetic determinations of plasma lipids.

Adult↗