👤 Jaroslav A Hubacek

Familial dysbetalipoproteinemia (FD) is an autosomal recessive (rarely dominant) inherited disorder that is almost exclusively associated with the apolipoprotein E gene (APOE) variability. Nonetheless, only a small proportion of APOE2/E2 subjects develop the phenotype for mixed dyslipidemia; the context of other trigger metabolic or genetic factors remains unknown. One hundred and one patients with FD and eighty controls (all APOE2/E2 homozygotes; rs429358) were screened for 18 single-nucleotide polymorphisms (SNPs) within the genes involved in triglyceride metabolism. Two SNPs were significantly associated with the FD phenotype (rs439401 within APOE; P < 0.0005 and rs964184 within ZPR1/APOA5/A4/C3/A1 gene cluster; P < 0.0001). Unweighted genetic risk scores - from these two SNPs (GRS2), and, also, additional 13 SNPs with P-value below 0.9 (GRS15) - were created as an additional tool to improve the risk estimation of FD development in subjects with the APOE2/E2 genotype. Both GRS2 and GRS15 were significantly (P < 0.0001) increased in patients and both GRSs discriminated almost identically between the groups (P = 0.86). Subjects with an unweighted GRS2 of three or more had an almost four-fold higher risk of FD development than other individuals (odds ratio (OR) 3.58, 95% confidence interva (CI): 1.78-7.18, P < 0.0005). We identified several SNPs that are individual additive factors influencing FD development. The use of unweighted GRS2 is a simple and clinically relevant tool that further improves the prediction of FD in APOE2/E2 homozygotes with corresponding biochemical characteristics. Show less

Plasma triglyceride (TG) levels represent a significant risk factor of cardiovascular and total mortality. Concentrations of TG in the plasma depend, to a large extent, on the genetic background, and the apolipoprotein A5 (APOA5) gene seems to be one of the most powerful players in the plasma TG metabolism regulation. In total, we analysed three tagging APOA5 (rs964184 rs662799, rs3135506) SNPs in 209 patients with plasma TG levels over 10 mmol/l (HTG) on at least one occasion and in 379 treatment-naïve controls (NTG) with plasma TG values within the normal range. Minor alleles of all three analysed APOA5 polymorphisms significantly (all P < 0.0001) increased the risk of hypertriglyceridaemia. The most significant association (P < 0.0000001) was observed for the rs964184 polymorphism, where the minor GG homozygotes had the odds ratio (OR, 95% CI) for hypertriglyceridaemia development 21.30 (8.09-56.07, P < 0.000001) in comparison with the major CC allele homozygotes. Carriers of at least one minor allele at rs3135506 had OR (95% CI) 4.19 (2.75-6.40); (P < 0.000005) for HTG development and similarly, carriers of a minor allele at rs662799 had OR (95% CI) 3.07 (2.00-4.72) (P < 0.0001). The cumulative presence of risk alleles (unweighted gene score) significantly differed between patients with episodes of high TG and controls at P < 0.0000001. There were 73 % of subjects without any of the risk alleles among the controls and 46 % in the patients. In contrast, the controls just included 3 % of subjects with score 3 and more in comparison with 18 % in HTG patients. We conclude that common APOA5 variants are very important genetic determinants of episodic hypertriglyceridaemia in the Czech population with a high potential to be applied in personalized medicine. Show less

Plasma triglyceride (TG) values are significant predictors of cardiovascular and total mortality. The plasma levels of TGs have an important genetic background. We analyzed whether 32 single nucleotide polymorphisms (SNPs) identified in genome-wide association studies are discriminators of hypertriglyceridemia (HTG) in the Czech population. The objective of this study was to replicate and test the original findings in an independent study and to re-analyze the gene score leading to HTG. In total, we analyzed 32 SNPs in 209 patients with plasma TG levels over 10 mmol/L (HTG group) and compared them in a case-control design with 524 treatment-naïve controls (normotriglyceridemic [NTG] group) with plasma TG values below 1.8 mmol/L. Sixteen SNPs were significantly associated with an increased risk of HTG development, with odds ratios (ORs) (95% confidence interval [CI]) varying from 1.40 (1.01-1.95) to 4.69 (3.29-6.68) (rs964184 within the APOA5 gene). Both unweighted (sum of the risk alleles) and weighted gene scores (WGS) (log of the achieved ORs per individual genotype) were calculated, and both gene scores were significantly different between groups. The mean score of the risk alleles was significantly increased in the HTG group compared to the NTG group (18.5 ± 2.5 vs. 15.7 ± 2.3, respectively; P < 0.00001). Subjects with a WGS over 9 were significantly more common in the HTG group (44.5%) than in the NTG group, in which such a high score was observed in only 4.7% of subjects (OR 16.3, 95% CI 10.0-36.7; P < 0.0000001). An increased number of risk genetic variants, calculated both in a weighted or unweighted manner, significantly discriminates between the subjects with HTG and controls. Population-specific sets of SNPs included into the gene score seem to yield better discrimination power. Show less

Apolipoprotein A5 (APOA5) is a small protein, expressed predominantly in the liver. In plasma, it is located on triglyceride rich lipoprotein particles (chylomicrones and VLDL) and on HDL. Plasma concentration of apolipoprotein A5 is very low, suggesting rather regulatory (activation of lipoprotein lipase, …) than structural function. APOA5 is an important determinant of plasma triglyceride concentration; this effect has been confirmed both on animal models, as well as on human studies. Minor alleles of three commonly analysed variants within this gene (rs662799, rs3135506, rs2075291) are associated with higher plasma TG values and increased risk of myocardial infarction, with some important interethnic differences observed. Further roles of APOA5; determination of BMI, diabetes and last but not least nutri- and pharmaco-genetic interactions are suggested, but without the definitive conclusions. Show less

Several smaller studies reported interactions between dietary factors and apolipoprotein A5 (APOA5) gene polymorphisms in determination of plasma lipids. We tested interactions between APOA5 haplotypes and dietary intake in determination of plasma triglycerides (TG) and other lipids. Participants (5487 males and females aged 45-69) were classified according to the number (0, 1, 2+) of minor APOA5 alleles (using T-1131 > C; rs662799 and Ser19 > Trp; rs3135506 polymorphisms) and into three groups of low (bottom 25%), medium (26th-75th percentile) and high (top 25%) of intake of total energy and total, saturated and polyunsaturated fats, assessed by food frequency questionnaire. The age-sex adjusted geometric means of plasma TG increased with the number of minor alleles, from 1.57 (standard error 0.01), to 1.79 (0.02) to 2.29 (0.10) mmol/L (p < 0.00001) but TG did not differ between groups with low, medium and high total energy intake (p = 0.251). TG concentrations were highest in subjects with the combination of 2+ minor alleles and the highest energy intake (mean 2.59 [0.19], compared with 1.62 [0.03] in subjects with lowest energy intake and no minor allele) but the interaction between energy intake and APOA5 haplotypes was not statistically significant (p = 0.186). Analogous analyses with total, saturated and polyunsaturated fat intake yielded similar nonsignificant results. Effects of APOA5 and dietary intakes on total and HDL cholesterol were weaker and no interactions were significant. In this Slavic Caucasian population sample, we did not detect the hypothesized interaction between common SNPs within the APOA5 gene and diet in determination of blood lipids. Show less

Despite the fact that statin treatment efficacy is very high, there are substantial differences in treatment effectiveness among individuals. It is supposed that genetic predisposition plays an important role in these differences, but the contribution of individual polymorphisms is poorly understood. So far, more than 30 genes have been examined with ambiguous results. Apolipoprotein A5 is an important determinant of plasma lipid concentrations and its genetic variation could account for some of the observed differences in the response to statin therapy. However, this has not been analyzed before. We examined the putative association between APOA5 SNPs (c.-1131T>C, c.56C>G and c.457G>A) and efficacy during 3 months of statin treatment in 187 adult Caucasians. Patients were treated with low-dose (10 or 20 mg per day) simvastatin (46.3%), atorvastatin (40.5%) and lovastatin (13.2%). The decrease in cholesterol was not significantly associated with the type or dose of statin. Carriers of the APOA5 genotype TT-1131 (n = 154) benefited more from statin treatment when compared with the C-1131 allele carriers (n = 33) (Delta low-density lipoprotein cholesterol: -36.3 +/- 15.1% vs Delta low-density lipoprotein cholesterol: -29.9 +/- 12.5%; p < 0.005, Mann-Whitney test). This result was independent of sex, age, BMI and APOE polymorphism. Our results suggest that the APOA5 gene variants may play an important role in the pharmacogenetics of statin treatment. Show less

Apolipoprotein A5 (APOA5) is a determinant of plasma lipids, and its role in body mass index (BMI) determination is discussed. This study was aimed at the investigation of the relationship between common APOA5 gene variants and body weight/plasma lipid decrease in overweight females. We analyzed 98 unrelated overweight and obese nondiabetic Czech females (BMI >27.5). APOA5 T-1131-->C and Ser19-->Trp variants were genotyped. Before and after 9 weeks of lifestyle modification, biochemical and anthropometrical measurements and assessment of nutritional intake were performed. The lifestyle modification program consisted of a reduction in energy intake and an exercise program (aerobic exercise 4 times per week, 60 min each). The mean age of the participants was 30.7 +/- 3.7 years, the mean BMI before the intervention was 31.4 +/- 3.8 and the weight loss was 5.9 +/- 2.5 kg (7 +/- 3%). There were 86 T-1131T homozygotes and 12 carriers of the C-1131 allele and 82 Ser19Ser homozygotes and 16 carriers of the Trp19 allele, respectively; 72 females had the commonest T-1131T/Ser19Ser haplotype. No significant association between BMI decrease and APOA5 variants was found, but T-1131T carriers have a significantly higher body weight both before and after the intervention (p < 0.05; p = not significant for BMI). The fasting glycemia was significantly higher in Trp19 carriers both before and after the intervention (p < 0.01). Further, plasma triglyceride levels decreased in Ser19Ser homozygotes but increased in Trp19 carriers (1.42 +/- 0.62 to 1.28 +/- 0.48 vs. 1.15 +/- 0.47 to 1.41 +/- 0.80 mmol/l; p < 0.05 for differences between the groups). Similarly, in carriers of at least 1 less common APOA5 allele (n = 26), plasma low-density lipoprotein cholesterol levels did not decrease as they did in T-1131T/Ser19Ser carriers (3.11 +/- 0.70 to 3.27 +/- 0.81 vs. 3.39 +/- 0.81 to 3.16 +/- 0.86 mmol/l; p < 0.05 for differences between the groups). APOA5 gene variants have effects on the decrease in plasma triglyceride and low-density lipoprotein cholesterol level in females in a model combining their dietary habits and physical activity changes. Show less

The purpose of this study was to identify rare APOA5 variants in 130 severe hypertriglyceridemic patients by sequencing, and to test their functionality, since no patient recall was possible. We studied the impact in vitro on LPL activity and receptor binding of 3 novel heterozygous variants, apoAV-E255G, -G271C, and -H321L, together with the previously reported -G185C, -Q139X, -Q148X, and a novel construct -Delta139 to 147. Using VLDL as a TG-source, compared to wild type, apoAV-G255, -L321 and -C185 showed reduced LPL activation (-25% [P=0.005], -36% [P<0.0001], and -23% [P=0.02]), respectively). ApoAV-C271, -X139, -X148, and Delta139 to 147 had little affect on LPL activity, but apoAV-X139, -X148, and -C271 showed no binding to LDL-family receptors, LR8 or LRP1. Although the G271C proband carried no LPL and APOC2 mutations, the H321L carrier was heterozygous for LPL P207L. The E255G carrier was homozygous for LPL W86G, yet only experienced severe hypertriglyceridemia when pregnant. The in vitro determined function of these apoAV variants only partly explains the high TG levels seen in carriers. Their occurrence in the homozygous state, coinheritance of LPL variants or common APOA5 TG-raising variant in trans, appears to be essential for their phenotypic expression. Show less

The importance of the apolipoprotein A5 (APOA5) gene in determining plasma triglyceride (TG) levels has been demonstrated in transgenic and knockout mice and confirmed by human association studies in different ethnic groups. We screened for nonsynonymous APOA5 mutations in patients with plasma TG levels >10 mmol/L. The coding sequence and promoter region of the APOA5 gene were sequenced in 95 individuals with severe hypertriglyceridemia (HTG). A large population sample of 3,202 individuals was screened by PCR and restriction analysis for presence of detected mutation. In total, three heterozygous carriers of 944C>T (Ala315>Val) were identified in the severe HTG patients, while 22 carriers were identified in the population sample. The rare allele frequency of the Val315 was significantly higher in the HTG sample than in controls (0.016 vs. 0.003, p<0.01, respectively). Most of the control Ala315Val carriers, however, had plasma lipid levels (TGs, total cholesterol and high-density lipoprotein cholesterol) within the usual range detected in the population. APOA5 Ala315>Val does not play any dominant/important role in the genetic determination of plasma TG levels, but the increased frequency in HTG patients compared to controls suggests that it might interact with other gene variants to cause HTG. Show less

The APOA5 and APOE genes play an important role in determination of plasma levels of triglycerides (TG) and total cholesterol (TC). We have analyzed APOA5 (T-1131>C and Ser19>Trp) and APOE (e2/e3/e4) variants in 2500 representatively selected Caucasians (1168 men, 1332 women). In female subjects (but not in male) an association between APOE polymorphism and TC was observed on the background of the common APOA5 haplotype (TT-1131/SerSer19) - APOE2 carriers have the lowest (5.12 (1.15) mmol/l) and the APOE4 carriers have the highest (6.05 (1.06) mmol/l) levels of plasma TC (P<0.001). If at least one APOA5 C-1131 or Trp19 allele was present, APOE exhibits no significant effect on plasma TC. APOA5 did not affect plasma TG levels, if APOE4 allele was present. In the presence of APOE2 or APOE3, carriers of the APOA5 alleles, C-1131 and/or Trp19, have higher TG levels (1.64 (1.05) mmol/l) than others (1.37 (0.75) mmol/l) (P<0.01). In male subjects, the same, but non-significant trend was observed. In female subjects, we have detected an interaction between APOE and APOA5 variants and plasma lipid levels. Show less

We tested the hypothesis that the MLXIPL rs3812316 variant predicts plasma triglyceride (TG) levels. We compared three groups of adult individuals: 162 persons with TG > 10 mmol/L, 266 persons with TG < 0.65 mmol/L, and 2,043 population-based controls (range of TG concentrations 0.7-8.7 mmol/L). We found a small difference in the frequency of the Gln allele carriers between population controls (20.4%) and persons with low TG (26.3%, P = 0.033). We found no difference between individuals with high TG and population controls, and there was no association between the MLXIPL variant and plasma TG levels among the population controls. Show less

The relationship between dietary composition and plasma lipids is to some extent genetically determined. It has been found that variants of some genes (e.g., apolipoprotein E and cholesterol 7-alpha hydroxylase) play an important role in changes in plasma lipid levels in response to dietary intervention. We analyzed the effect of variation in the apolipoprotein (APO) APOA1/C3/A4/A5 gene cluster on decreases in plasma cholesterol levels over an 8-year follow-up study. Men (n=133) from the Czech population, for which dietary composition has markedly changed (red meat 80-->68 kg/person/year, animal fat 16-->9 kg/person/year, fruits and vegetables 133-->150 kg/person/year) were recruited. APOA1 (G-75>A and C83>T), APOC3 (C-482>T and C3238>G), APOA4 (Thr347>Ser and Gln360His) and APOA5 (T-1131>C, Ser19>Trp and Val153>Met) variants were analyzed by PCR and restriction analysis. Lipid levels were analyzed in 1988 and 1996. Dietary information was obtained from the Institute of Agricultural Economy. In APOA5 Ser19Ser homozygotes (n=105), plasma cholesterol was relatively stable over the years (6.1+/-1.3 and 5.6+/-1.0 mmol/L in 1988 and 1996), but the decrease was much higher in Trp19 carriers (n=27; 6.5+/-1.6 vs. 5.1+/-1.1 mmol/L). This difference in change is significant at p<0.005. Similarly, a better response to dietary changes was detected in carriers of the common APOA4 haplotypes Thr-347Thr/Gln360Gln and Thr347Ser/Gln360Gln (n=102; 6.3+/-1.3 and 5.5+/-1.1 mmol/L in 1988 and 1996, p<0.001). Total cholesterol was relatively stable over time in carriers (n=18) of at least one His360 allele and/or two Ser347 alleles (5.7+/-1.1 and 5.5+/-0.9 mmol/L in 1988 and 1996, n.s.). Other variants analyzed did not influence the change in lipid measurements over time. APOA4 and APOA5 variants may play an important role in the individual sensitivity of lipid parameters to dietary composition in men. Show less

To evaluate whether the relationship between dietary composition and plasma lipid levels is genetically determined. We have evaluated the influence of common apolipoprotein A5 (APOA5) variants (T-1131 > C, Ser19 > Trp and Val153 > Met) on plasma lipid concentrations in 117 males for whom dietary composition markedly changed and total cholesterol decreased (from 6.21 +/- 1.31 mmol/L in 1988 to 5.43 +/- 1.06 mmol/L in 1996) over an 8 year follow-up study. APOA5 T-1131 > C and Val153 > Met variants did not influence the change in lipid measures over time. In Ser/Ser19 homozygotes, the plasma cholesterol was relatively stable over the years (6.1 +/- 1.2 mmol/L in 1988 and 5.6 +/- 1.0 mmol/L in 1996, -8%, P < 0.01). In contrast, in the Trp19 carriers, the decrease of the plasma cholesterol was more than 20% (6.5 +/- 1.6 mmol/L in 1988 and 5.1 +/- 1.0 mmol/L in 1996) (P < 0.001). The difference of the changes is significant (8% vs. 20%, P < 0.005). Changes in other analyzed lipid parameters have not been significantly associated with APOA5 variants. Ser19 > Trp variant in the APOA5 gene may play an important role in an individual's sensitivity to dietary composition. Show less

The importance of the APOAV gene for the determination of plasma triglyceride levels has been suggested by creations of transgenic and knockout mice and confirmed in population studies. We examined whether the newly detected APOAV variant is associated with plasma lipid levels and risk of myocardial infarction (MI). APOAV polymorphism (Val153>Met) was genotyped in 1191 males and 1368 females representatively selected from the Czech population. Lipid levels were analyzed in 1997 and 2001 in all individuals. Subsequently, we have analyzed the genotype frequencies of APOAV polymorphism in 435 male patients with MI. Val153>Met variation in the APOAV gene affects the plasma high-density lipoprotein cholesterol levels showing a higher level in Val/Val homozygotes than in Met carriers in both years (1.51 +/- 0.36 and 1.52 +/- 0.37 mmol/L compared with 1.42 +/- 0.33 and 1.39 +/- 0.35 mmol/L, P < .01). This association has been observed in females but not in males. Other analyzed lipid parameters (total cholesterol, low-density lipoprotein cholesterol, and triglycerides) have not been associated with APOAV Val153>Met variant. In a group of patients with MI, the frequency of the Met153 carriers was not significantly different from the male population sample (6.5% vs 6.4%). Val153>Met variation in the APOAV gene plays a sex-specific role in genetic determination of plasma high-density lipoprotein cholesterol levels, but does not influence risk of MI in males. Show less

High plasma levels of triglycerides are an independent risk factor for the development of cardiovascular disease. Apolipoprotein A5 (APOA5) is a new member of the apolipoprotein APOA1/C3/A4 gene cluster, found by comparative sequencing analysis. The importance of the APOA5 gene for determination of plasma triglyceride levels has been suggested by the creation of transgenic and knock-out mice (transgenic mice displayed significantly reduced triglycerides, whereas knock-out mice had a high level of triglycerides). It has now been clearly established that distinct polymorphisms in the APOA5 gene consistently influence plasma triglycerides in a wide range of human populations, although some differences between ethnic groups and males and females were described. The possible roles of APOA5 variants in determining the risk of myocardial infarction and coronary artery disease development, as well as in the determination of low-density lipoprotein-particle size or plasma concentrations of C-reactive protein and high-density lipoprotein-cholesterol, are also summarized. Show less

APOAV is newly described protein, which plays a crucial role in the determination of plasma triglyceride (TG) levels. Remnant lipoproteins (RLPs) result from partial catabolised TG-rich particles. Elevated levels of RLP are associated with atherosclerosis, and they are a predictor of coronary events in patients with coronary artery disease. We have evaluated the influence of APOAV polymorphisms (T-1131/C, Ser19/Trp and Val153/Met were measured by PCR and restriction analysis) on plasma levels of RLP-cholesterol and RLP-TG in 285 unrelated representative selected individuals (131 men and 154 women) aged 33-72 years. RLP-cholesterol and RLP-TG levels were not significantly influenced by the APOAV variants either in whole population or in males and females, if analyzed separately. We conclude that variations T-1131/C, Ser19/Trp and Val153/Met in the APOAV gene have no effect on plasma levels of remnant particles. Show less

The importance of an APOAV gene for plasma triglyceride level determination has been shown on transgenic and knockout mice. We examined whether APOAV variants are associated with plasma triglyceride levels and risk of myocardial infarction (MI). We have evaluated the influence of APOAV polymorphisms (T-1131>C and S19>W) on plasma triglycerides in 1191 males and 1368 females representatively selected from the Czech population. Triglycerides have been analysed in 1997 and 2001. Subsequently, we have analysed the genotype frequencies of the APOAV polymorphism in 435 patients with MI. T-1131>C variation in the APOAV gene affects the plasma triglyceride showing a higher level in C-1131 carriers than in T/T-1131 homozygotes. This association has been observed both in males and females (p < 0.001). Similarly, plasma triglycerides were also significantly influenced by the S19>W APOAV genotypes. In both males and females, the W19 carriers have triglycerides significantly (p < 0.001) higher compared to the S19 homozygotes. In a group of MI patients, the frequency of the rare homozygotes for at least one APOAV polymorphism (C/C-1131 and/or W/W19) was significantly higher than that in the population sample (7.4 vs 2.0%, p < 0.00001). We conclude that variations in the APOAV gene not only play a role in genetic determination of triglyceride levels but also could influence risk of MI. Show less

The recently identified apolipoprotein A5 gene (APOA5) has been shown to play an important role in determining plasma triglyceride concentrations in humans and mice. We previously identified an APOA5 haplotype (designated APOA5*2) that is present in approximately 16% of Caucasians and is associated with increased plasma triglyceride concentrations. In this report we describe another APOA5 haplotype (APOA5*3) containing the rare allele of the single nucleotide polymorphism c.56C>G that changes serine to tryptophan at codon 19 and is independently associated with high plasma triglyceride levels in three different populations. In a sample of 264 Caucasian men and women with plasma triglyceride concentrations above the 90th percentile or below the 10th percentile, the APOA5*3 haplotype was more than three-fold more common in the group with high plasma triglyceride levels. In a second independently ascertained sample of Caucasian men and women (n=419) who were studied while consuming their self-selected diets as well as after high-carbohydrate diets and high-fat diets, the APOA5*3 haplotype was associated with increased plasma triglyceride levels on all three dietary regimens. In a third population comprising 2660 randomly selected individuals, the APOA5*3 haplotype was found in 12% of Caucasians, 14% of African-Americans and 28% of Hispanics and was associated with increased plasma triglyceride levels in both men and women in each ethnic group. These findings establish that the APOA5 locus contributes significantly to inter-individual variation in plasma triglyceride levels in humans. Together, the APOA5*2 and APOA5*3 haplotypes are found in 25-50% of African-Americans, Hispanics and Caucasians and support the contribution of common human variation to quantitative phenotypes in the general population. Show less

Comparison of genomic DNA sequences from human and mouse revealed a new apolipoprotein (APO) gene (APOAV) located proximal to the well-characterized APOAI/CIII/AIV gene cluster on human 11q23. Mice expressing a human APOAV transgene showed a decrease in plasma triglyceride concentrations to one-third of those in control mice; conversely, knockout mice lacking Apoav had four times as much plasma triglycerides as controls. In humans, single nucleotide polymorphisms (SNPs) across the APOAV locus were found to be significantly associated with plasma triglyceride levels in two independent studies. These findings indicate that APOAV is an important determinant of plasma triglyceride levels, a major risk factor for coronary artery disease. Show less

To evaluate the association between plasma lipids and insulin and variation in the genes for apolipoproteins (APO) E (CfoI), B (insertion/deletion), C1 (HpaI), and C3 (C-482T, C3238G) in a population-based Czech Slavonic study. In 131 men and 154 women, polymorphisms were investigated using PCR. In the same subjects plasma lipid levels and insulin were measured. In the women, carriers of the e4 allele had higher apoB (p = 0.03) and triglyceride (p = 0.03) compared to e3 homozygotes, whereas in the men, the effect of the e4 allele was seen on total cholesterol (p = 0.02), LDL cholesterol (p = 0.003) and apoB (p = 0.001). Compared with SP27 (insertion) homozygotes of the APOB polymorphism, women SP24 (deletion) homozygotes had higher levels of total (p = 0.003) and LDL cholesterol (p = 0.007) and apoB (p = 0.05). No significant effect was seen in the men. Women homozygous for the APOC3 -482T allele had higher insulin levels than -482C homozygotes (p = 0.03). Men homozygous for APOC3 -482T allele have the highest plasma triglyceride level (p = 0.02). The APOC1 polymorphism exhibited no significant effect on any of the parameters studied. In this sample, variation at the APOE, APOB and APOC3 genes play a role in determining plasma levels of insulin and lipids, and emphasize the importance of gender-associated effects in the genetic determinations. Show less

Remnant particles of triglyceride-rich lipoproteins (RLP) are known to be a strong predictor of atherogenicity. The serum concentrations of remnant-like particle triglyceride (RLPTG) and remnant-like particle cholesterol (RLPC) have been determined in a representative sample of the Czech MONICA study (n = 285). The relationship was investigated between remnant particle triglyceride/cholesterol concentrations and polymorphisms in the genes APOC3 (-482C-->T/3238C-->G), APOE (epsilon2/epsilon3/epsilon4), APOCI (-317-321ins), APOB (signal peptide), hepatic lipase (LIPE, -480C-->T), and lipoprotein lipase (LPL, S447X). Univariate analysis showed significant effects on RLPTG associated only with the APOE genotype (P = 0.009), the APOC3 -482C-->T genotype (P = 0.018), and the APOCI -317-321ins (P = 0.014) genotype and significant effects on RLPC with APOE (P = 0.01) and APOCI -317-321ins (P = 0.021). The raising effect of the APOE genotype for both remnant cholesterol and triglyceride was confined to the epsilon2/4 (n = 6) and varepsilon4/4 (n = 3) groups, and thus when the epsilon2/4 group was omitted in order to analyze by allele (epsilon2+/epsilon3+/epsilon4+), significance was lost (P = 0.6). There was strong linkage disequilibrium between the APOE and APOCI alleles (chi(2), P < 0.001) and a multivariate ANOVA of RLPTG with all three significantly associated variants as factors demonstrated that while the APOC3 -482C-->T effect was independent of the others (P = 0.003), the APOCI -317-321ins and APOE effects were not. This was also true for the APOCI -317-321ins and APOE effects on RLPC. To assess whether APOE-CI effects on RLPC were independent of their effects on total cholesterol and triglyceride levels, multiple linear regression was used. Using multiple linear regression, it appeared that the APOE-CI effects on RLPC were independent of their effects on plasma cholesterol, but the effects of APOC3 and APOE-CI on RLPTG could not be separated from their effects on plasma Tg levels. Further characterization of this remnant particle phenotype and its genetic determinants may lead to a better understanding of its metabolism and contribution to atherosclerosis. Show less