Familial hypercholesterolaemia workshop for leveraging point-of-care testing and personalised medicine in association with the Lipid and Atherosclerosis Society of Southern Africa.

Familial hypercholesterolaemia (FH) is a common autosomal dominantly inherited disorder in which impaired clearance of plasma low-density lipoprotein cholesterol causes premature atherosclerotic vascular disease and tendon xanthomata. This workshop aimed to consolidate information on the diagnosis and management of FH in South Africa. The genetic causes include mutations in the LDL receptor, apolipoprotein B100 and proprotein convertase subtilisin/kexin type 9 (PCSK9). Additionally, the concatenation of multiple gene variants can result in polygenic FH. Therapeutic measures include a healthy lifestyle, statins and cholesterol-absorption inhibitors that will achieve control of the dyslipidaemia in the majority of cases. The recently introduced monoclonal antibodies to PCSK9 can improve achievement of target concentration in severe cases. FH is present in all sectors of the South African population but there is sparse documentation in the indigenous African populations. FH should be actively sought, diagnosed and treated with judicious pharmacotherapy and screening of relatives.

Telomere shortening over 6 years is associated with increased subclinical carotid vascular damage and worse cardiovascular prognosis in the general population.

INTRODUCTION: Leucocyte telomere length (LTL) is an important determinant of telomere function and cellular replicative capacity. The aim of the present study was to examine prospectively the associations between telomere shortening (TS) and both the progression of atherosclerosis and the incidence of cardiovascular events (CVEs). MATERIALS AND METHODS: Leucocyte telomere length was measured by quantitative polymerase chain reaction to determine the ratio of telomere length to single-copy gene (T/S) in 768 subjects (462 female and 306 male) enrolled in a large general population survey [the Progressione della Lesione Intimale Carotidea (PLIC study)]. Common carotid artery intima-media thickness was determined at baseline and after 6 years of follow-up, and the associations between TS and the progression of atherosclerosis and incidence of CVEs were evaluated. RESULTS: Mean LTL was 1.25 ± 0.92 T/S (median 1.14) at baseline and 0.70 ± 0.37 T/S (median 0.70) after 6 years of follow-up. Median 6-year LTL change was -0.46 T/S [interquartile range (IQR) -0.57 to 1.06], equating to -0.078 T/S [IQR(-0.092 to 0.176)] per year. Of note, telomere lengthening occurred in 30.4% of subjects. After adjustment for classical cardiovascular disease (CVD) risk factors (age, gender, smoking, physical activity, alcohol consumption, systolic blood pressure, glucose levels, lipid profile and therapies), TS was associated with incident subclinical carotid vascular damage [hazard ratio (HR) 5.19, 95% confidence interval (CI) 1.20-22.4, P = 0.028]. Finally, subjects in whom LTL shortened over time showed an increased risk of incident CVE, compared to those in whom LTL lengthened (HR 1.69, CI 1.02-2.78, P = 0.041). CONCLUSION: These data indicate that TS is associated with increased risk of subclinical carotid vascular damage and increased incidence of CVEs beyond CVD risk factors in the general population, whereas LTL lengthening is protective.

Genetic analysis of NR0B1 in congenital adrenal hypoplasia patients: identification of a rare regulatory variant resulting in congenital adrenal hypoplasia and hypogonadal hypogonadism without testicular carcinoma in situ.

There have been few testicular histology reports of adult patients with congenital adrenal hypoplasia/hypogonadal hypogonadism (AHC/HH), but Leydig cell hyperplasia has been observed, an indicator of the possibility of malignant transformation. We aimed to define the basis of AHC/HH in 4 pedigrees of different ethnic backgrounds. One patient was elected to have testicular biopsy which was examined for evidence of carcinoma in situ (CIS). NR0B1 mutation analysis was performed by sequence analysis. NR0B1 expression was investigated by RT-PCR. Testicular biopsy sections were stained with HE or immunostained for OCT3/4, an established marker of CIS. We identified NR0B1 variants in the 4 AHC pedigrees: pedigree 1 (United Arab Emirates), c.1130A>G predicting p.(Glu377Gly); pedigree 2 (English Caucasian), c.327C>A predicting p.(Cys109*); pedigree 3 (Oman), a 6-bp deletion of a direct repeat, c.857_862delTGGTGC predicting p.(Leu286_Val287del); pedigree 4 (English Caucasian), c.1168+1G>A, a regulatory variant within the NR0B1 splice donor site. This last male patient, aged 30 years, presented with evidence of HH but incomplete gonadotrophin deficiency, following an earlier diagnosis of Addison's disease at 3 years. Hormonal therapy induced virilisation. Testicular biopsy was performed. The c.1168+1G>A variant abrogated normal splicing of testicular mRNA. Histological examination showed poorly organised testicular architecture and absence of spermatozoa. Morphological analyses and the absence of immunohistochemical staining for OCT3/4 excluded the presence of malignant germ cell cancer and its precursor lesion, CIS. These studies add to the knowledge of the types and ethnic diversity of NR0B1 mutations and their associated phenotypes, and provide insight into the assessment and interpretation of testicular histology in AHC and HH.

IRS1 gene variants, dysglycaemic metabolic changes and type-2 diabetes risk.

BACKGROUND AND AIMS: A recent genome-wide association study identified rs2943641C > T, 500 kb from the insulin receptor substrate-1 gene (IRS1), as a type-2 diabetes (T2D) susceptibility locus. We aimed to replicate this association by meta-analysis and examine whether common variants within IRS1, present on the HumanCVD BeadChip, were associated with T2D risk. METHODS AND RESULTS: We genotyped rs2943641 in 2389 prevalent or incident T2D patients and 6494 controls from two prospective and three case studies based in UK and in the European Atherosclerosis Research Study-II (EARSII; n = 714). Thirty-three IRS1 variants had been genotyped in the prospective Whitehall-II study (n = 4752) using the HumanCVD BeadChip. In a fixed-effects meta-analysis of the UK study cohorts rs2943641T allele was associated with 6% lower risk of T2D (p = 0.18), with T-allele carriers having an odds ratio (OR) of 0.89 (95% confidence interval [CI]: 0.80-1.00, p = 0.056) compared to CC subjects. The T-allele was also associated with lower fasting insulin and homeostasis model assessment index of insulin resistance in Whitehall-II and with lower post-load insulin after an oral glucose tolerance test in EARSII (all p < 0.05). None of the IRS1 variants on the chip showed linkage disequilibrium with rs2943641. In silico analysis with follow-up genotyping (total n = 9313) identified that the rare allele of the IRS1 promoter variant rs6725556A > G showed association with reduced T2D risk (OR per G-allele: 0.82, 95%CI: 0.69-0.96, p = 0.015). CONCLUSIONS: We confirm the association of rs2943641T with T2D protection. There is a possible independent effect on risk of a putative IRS1 promoter variant.

Variants of ADRA2A are associated with fasting glucose, blood pressure, body mass index and type 2 diabetes risk: meta-analysis of four prospective studies.

AIMS/HYPOTHESIS: We quantified the effect of ADRA2A (encoding α-2 adrenergic receptor) variants on metabolic traits and type 2 diabetes risk, as reported in four studies. METHODS: Genotype data for ADRA2A single nucleotide polymorphisms (SNPs) rs553668 and rs10885122 were analysed in >17,000 individuals (1,307 type 2 diabetes cases) with regard to metabolic traits and type 2 diabetes risk. Two studies (n = 9,437), genotyped using the Human Cardiovascular Disease BeadChip, provided 12 additional ADRA2A SNPs. RESULTS: Rs553668 was associated with per allele effects on fasting glucose (0.03 mmol/l, p = 0.016) and type 2 diabetes risk (OR 1.17, 95% CI 1.04-1.31; p = 0.01). No significant association was observed with rs10885122. Of the 12 SNPs, several showed associations with metabolic traits. Overall, after variable selection, rs553668 was associated with type 2 diabetes risk (OR 1.38, 95% CI 1.09-1.73; p = 0.007). rs553668 (per allele difference 0.036 mmol/l, 95% CI 0.008-0.065) and rs17186196 (per allele difference 0.066 mmol/l, 95% CI 0.017-0.115) were independently associated with fasting glucose, and rs17186196 with fasting insulin and HOMA of insulin resistance (4.3%, 95% CI 0.6-8.1 and 4.9%, 95% CI 1.0-9.0, respectively, per allele). Per-allele effects of rs491589 on systolic and diastolic blood pressure were 1.19 mmHg (95% CI 0.43-1.95) and 0.61 mmHg (95% CI 0.11-1.10), respectively, and those of rs36022820 on BMI 0.58 kg/m(2) (95% CI 0.15-1.02). CONCLUSIONS/INTERPRETATION: Multiple ADRA2A SNPs are associated with metabolic traits, blood pressure and type 2 diabetes risk. The α-2 adrenergic receptor should be revisited as a therapeutic target for reduction of the adverse consequences of metabolic trait disorders and type 2 diabetes.

Genetic variation within IL18 is associated with insulin levels, insulin resistance and postprandial measures.

BACKGROUND AND AIMS: IL-18 expression is up-regulated in atherosclerotic plaques, and higher levels are seen in obese and Type 2 Diabetic individuals. More recently, a possible role for IL-18 in glucose and energy homeostasis has been suggested. METHODS AND RESULTS: We investigated variation within the IL18 gene and its association with measures of obesity and the metabolic syndrome. Five IL18 tagging single nucleotide polymorphisms (rs1946519, rs2043055, rs549908, rs360729, rs3882891) were selected and genotyped in the Gene-Diet Attica Investigation on childhood obesity (GENDAI) (age range 10-14 yrs); in young European men in the second European Atherosclerosis Research offspring Study (EARSII), an offspring study (age range 18-28 yrs) and in a group of healthy women from the Greek Obese Women study (GrOW) (age range 18-74 yrs). Six common haplotypes were observed. In GrOW, Hap6 (Frequency-2.6%) was associated with higher insulin levels (p<0.0001), estimates of HOMA(-Insulin Resistance) (p<0.0001) and HOMA(-ß-cell) (p<0.0001) compared to the common haplotype Hap1 (Frequency-33.2%). In EARSII, rs2043055 was associated with peak and area under the curve triglycerides (p=0.001 and p=0.002, respectively) after an oral fat tolerance test in 'cases' but not 'controls'. None of the haplotypes were associated with measures of body fatness in any of the studies. CONCLUSION: Association of IL18 variation with insulin levels and estimates of insulin resistance were only observed in our adult study, suggesting that the effects of IL-18 are only associated with increasing age. Taken together with the association of IL18 variants with post-prandial measures, this provides support for IL-18 as a metabolic factor.

Haplotype and genotype effects of the F7 gene on circulating factor VII, coagulation activation markers and incident coronary heart disease in UK men.

BACKGROUND: Evidence for the associations of single nucleotide polymorphisms (SNPs) in the F7 gene and factor (F)VII levels and with risk of coronary heart disease (CHD) is inconsistent. We examined whether F7 tagging SNPs (tSNPs) and haplotypes were associated with FVII levels, coagulation activation markers (CAMs) and CHD risk in two cohorts of UK men. METHODS: Genotypes for eight SNPs and baseline levels of FVIIc, FVIIag and CAMs (including FVIIa) were determined in 2773 healthy men from the Second Northwick Park Heart Study (NPHS-II). A second cohort, Whitehall II study (WH-II, n = 4055), was used for replication analysis of FVIIc levels and CHD risk. RESULTS: In NPHS-II the minor alleles of three SNPs (rs555212, rs762635 and rs510317; haplotype H2) were associated with higher levels of FVIIag, FVIIc and FVIIa, whereas the minor allele for two SNPs (I/D323 and rs6046; haplotype H5) was associated with lower levels. Adjusted for classic risk factors, H2 carriers had a CHD hazard ratio of 1.34 [95% confidence interval (CI): 1.12-1.59; independent of FVIIc], whereas H5 carriers had a CHD risk of 1.29 (95% CI: 1.01-1.56; not independent of FVIIc) and significantly lower CAMs. Effects of haplotypes on FVIIc levels were replicated in WH-II, as was the association of H5 with higher CHD risk [pooled-estimate odds ratio (OR) 1.16 (1.00-1.36), P = 0.05], but surprisingly, H2 exhibited a reduced risk for CHD. CONCLUSION: tSNPs in the F7 gene strongly influence FVII levels. The haplotype associated with low FVIIc level, with particularly reduced functional activity, was consistently associated with increased risk for CHD, whereas the haplotype associated with high FVIIc level was not.

APOE, CETP and LPL genes show strong association with lipid levels in Greek children.

BACKGROUND AND AIMS: Studies have consistently demonstrated that variants in a number of candidate genes are significant determinants of lipid levels in adults. However, few studies have investigated the impact of these variants in children. Therefore, in the present investigation we examined the influence of ten common variants in the genes for lipoprotein lipase (LPL-S447X), cholesterol ester transfer protein (CETP-Taq1B) apolipoprotein (APO) E (epsilon2, epsilon3, epsilon4), APOA5 (-1131C>T and S19W), APOA4 (S347T) and APOC3 (-482C>T; 1100C>T and 3238G>C) on lipoprotein levels children from the Gene-Diet Attica Investigation on childhood obesity (GENDAI). METHODS AND RESULTS: The ten variants selected were genotyped in 882 Greek children, mean age: 11.2+/-0.7 years (418 females and 464 males). Genotypes were assessed using TaqMan technology. Significantly higher total cholesterol (TC) (p=0.0001) and low-density lipoprotein cholesterol (LDL-C) (p<0.0001) were observed in APOE epsilon4 carriers compared to epsilon3/epsilon3 homozygotes and epsilon2 carriers. The association of APOE genotype with TC and high-density lipoprotein cholesterol (HDL-C) ratio (p=0.0008) was further modulated by body mass index. Carriers of the CETP TaqIB B2 allele had significantly higher HDL-C (p<0.0001) and significantly lower TC: HDL-C ratio (p<0.0001) compared to B1/B1 individuals. No significant associations were observed between APOA4, APOA5 and APOC3 variants and serum lipids. CONCLUSION: This study demonstrates that these common variants are associated with lipid levels in this healthy paediatric cohort, suggesting that even in these young children there may be potential in predicting their lifelong exposure to an adverse lipid profile.

Inflammatory biomarkers and the prediction of coronary events among people at intermediate risk: the EPIC-Norfolk prospective population study.

OBJECTIVE: To evaluate the role of the inflammatory biomarkers C-reactive protein (CRP), myeloperoxidase, paraoxonase, secretory phospholipase A2 group IIA (sPLA2), lipoprotein-associated phospholipase A2, fibrinogen, macrophage chemoattractant protein-1 and adiponectin, in predicting the risk of coronary heart disease (CHD) among people estimated to be at intermediate risk according to the Framingham Risk Score (FRS). DESIGN: Prospective case-control study nested in EPIC-Norfolk cohort. SETTING: Norfolk, UK. PATIENTS: Apparently healthy men and women aged 45-79 years. MAIN OUTCOME MEASURES: Risk of future coronary artery disease. RESULTS: For participants predicted to be at intermediate risk by the FRS, the highest c statistics were observed for FRS plus CRP (0.61, 95% CI 0.57 to 0.65) and for FRS plus sPLA2 (0.56, 95% CI 0.52 to 0.6). Net correct reclassification of cases and controls for each marker was assessed for people across the entire risk spectrum and again for people at intermediate risk only. The largest differences were observed for CRP, 12.0% net reclassification improvement in the entire risk spectrum and 28.4% net reclassification improvement in the intermediate-risk group and for sPLA2, the net reclassification improvement was 6.4% in the entire risk spectrum and 16.3% in the intermediate-risk group. CONCLUSIONS: The discriminatory potential of inflammatory biomarkers was substantially different when analysed across the entire risk spectrum compared with the subgroup of people at intermediate risk.

Effects of six APOA5 variants, identified in patients with severe hypertriglyceridemia, on in vitro lipoprotein lipase activity and receptor binding.

OBJECTIVE: 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. METHODS AND RESULTS: 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. CONCLUSIONS: 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.

Age and origin of major Smith-Lemli-Opitz syndrome (SLOS) mutations in European populations.

BACKGROUND: Smith-Lemli-Opitz syndrome (SLOS) (MIM 270 400) is an autosomal recessive multiple congenital anomalies/mental retardation syndrome caused by mutations in the Delta7-sterol reductase (DHCR7, E.C.1.3.1.21) gene. The prevalence of SLOS has been estimated to range between 1:15000 and 1:60000 in populations of European origin. METHODS AND RESULTS: We have analysed the frequency, origin, and age of DHCR7 mutations in European populations. In 263 SLOS patients 10 common alleles (c.964-1G>C, p.Trp151X, p.Thr93Met, p.Val326Leu, p.Arg352Trp, p.Arg404Cys, p.Phe302Leu, p.Leu157Pro, p.Gly410Ser, p.Arg445Gln) were found to constitute approximately 80% of disease-causing mutations. As reported before, the mutational spectra differed significantly between populations, and frequency peaks of common mutations were observed in North-West (c.964-1G>C), North-East (p.Trp151X, p.Val326Leu) and Southern Europe (p.Thr93Met). SLOS was virtually absent from Finland. The analysis of nearly 8000 alleles from 10 different European populations confirmed a geographical distribution of DHCR7 mutations as reported in previous studies. The common Null mutations in Northern Europe (combined ca. 1:70) occurred at a much higher frequency than expected from the reported prevalence of SLOS. In contrast the most common mutation in Mediterranean SLOS patients (p.Thr93Met) had a low population frequency. Haplotypes were constructed for SLOS chromosomes, and for wild-type chromosomes of African and European origins using eight cSNPs in the DHCR7 gene. The DHCR7 orthologue was sequenced in eight chimpanzees (Pan troglodytes) and three microsatellites were analysed in 50 of the SLOS families in order to estimate the age of the three major SLOS-causing mutations. CONCLUSIONS: The results indicate a time of first appearance of c.964-1G>C and p.Trp151X some 3000 years ago in North-West and North-East Europe, respectively. The p.Thr93Met mutations on the J haplotype has probably first arisen approximately 6000 years ago in the Eastern Mediterranean. Together, it appears that a combination of founder effects, recurrent mutations, and drift have shaped the present frequency distribution of DHCR7 mutations in Europe.

Collaborative meta-analysis of individual participant data from observational studies of Lp-PLA2 and cardiovascular diseases.

BACKGROUND: A large number of observational epidemiological studies have reported generally positive associations between circulating mass and activity levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and the risk of cardiovascular diseases. Few studies have been large enough to provide reliable estimates in different circumstances, such as in different subgroups (e.g., by age group, sex, or smoking status) or at different Lp-PLA2 levels. Moreover, most published studies have related disease risk only to baseline values of Lp-PLA2 markers (which can lead to substantial underestimation of any risk relationships because of within-person variability over time) and have used different approaches to adjustment for possible confounding factors. OBJECTIVES: By combination of data from individual participants from all relevant observational studies in a systematic 'meta-analysis', with correction for regression dilution (using available data on serial measurements of Lp-PLA2), the Lp-PLA2 Studies Collaboration will aim to characterize more precisely than has previously been possible the strength and shape of the age and sex-specific associations of plasma Lp-PLA2 with coronary heart disease (and, where data are sufficient, with other vascular diseases, such as ischaemic stroke). It will also help to determine to what extent such associations are independent of possible confounding factors and to explore potential sources of heterogeneity among studies, such as those related to assay methods and study design. It is anticipated that the present collaboration will serve as a framework to investigate related questions on Lp-PLA2 and cardiovascular outcomes. METHODS: A central database is being established containing data on circulating Lp-PLA2 values, sex and other potential confounding factors, age at baseline Lp-PLA2 measurement, age at event or at last follow-up, major vascular morbidity and cause-specific mortality. Information about any repeat measurements of Lp-PLA2 and potential confounding factors has been sought to allow adjustment for possible confounding and correction for regression dilution. The analyses will involve age-specific regression models. Synthesis of the available observational studies of Lp-PLA2 will yield information on a total of about 15 000 cardiovascular disease endpoints.

The apolipoprotein A-V genotype and plasma apolipoprotein A-V and triglyceride levels: prospective risk of type 2 diabetes. Results from the Northwick Park Heart Study II.

AIMS/HYPOTHESIS: We sought to establish the relationship between plasma apolipoprotein A-V (APOA5, previously known as apoA-V) and triglyceride levels and to determine the impact of the APOA5 genotype on APOA5 levels and development of type 2 diabetes in a 15-year follow-up study of healthy UK men. MATERIALS AND METHODS: APOA5 -1131T>C and S19W genotypes were determined in 2,490 men, of whom 145 subsequently developed type 2 diabetes. In a subset of 299 men, we also determined APOA5 levels. RESULTS: Plasma APOA5 levels positively correlated with triglycerides (r=0.18, p<0.002) and were not different in men who subsequently developed type 2 diabetes compared with healthy men (p=0.7). Carriers of either APOA5 W19 or -1131C had, as expected, higher plasma triglycerides. However, while W19 carriers had significantly higher APOA5 levels (p=0.0003), APOA5 levels were not associated with -1131T>C (p=0.63), reinforcing the idea that the reported -1131C association with triglycerides levels is due to linkage disequilibrium with variants in the APOC3 gene, and not due to the direct effect on APOA5 levels. Overall no effect of APOA5 -1131T>C or S19W was found on type 2 diabetes risk. CONCLUSIONS/INTERPRETATION: In contrast to animal studies, in man, plasma APOA5 positively correlates with plasma triglyceride levels. In prospective analysis, with the caveat that numbers were small, APOA5 genotypes do not appear to have an impact on risk of development of type 2 diabetes.

Apo B versus cholesterol in estimating cardiovascular risk and in guiding therapy: report of the thirty-person/ten-country panel.

There is abundant evidence that the risk of atherosclerotic vascular disease is directly related to plasma cholesterol levels. Accordingly, all of the national and transnational screening and therapeutic guidelines are based on total or LDL cholesterol. This presumes that cholesterol is the most important lipoprotein-related proatherogenic risk variable. On the contrary, risk appears to be more directly related to the number of circulating atherogenic particles that contact and enter the arterial wall than to the measured concentration of cholesterol in these lipoprotein fractions. Each of the atherogenic lipoprotein particles contains a single molecule of apolipoprotein (apo) B and therefore the concentration of apo B provides a direct measure of the number of circulating atherogenic lipoproteins. Evidence from fundamental, epidemiological and clinical trial studies indicates that apo B is superior to any of the cholesterol indices to recognize those at increased risk of vascular disease and to judge the adequacy of lipid-lowering therapy. On the basis of this evidence, we believe that apo B should be included in all guidelines as an indicator of cardiovascular risk. In addition, the present target adopted by the Canadian guideline groups of an apo B <90 mg dL(-1) in high-risk patients should be reassessed in the light of the new clinical trial results and a new ultra-low target of <80 mg dL(-1) be considered. The evidence also indicates that the apo B/apo A-I ratio is superior to any of the conventional cholesterol ratios in patients without symptomatic vascular disease or diabetes to evaluate the lipoprotein-related risk of vascular disease.

Lp-PLA2 activity and PLA2G7 A379V genotype in patients with diabetes mellitus.

Lipoprotein associated phospholipase A2 (Lp-PLA2) modulates low-density lipoprotein (LDL) oxidation by hydrolysing oxidised phospholipids present on particle surfaces. We investigated whether Lp-PLA2 activity and PLA2G7 A379V genotype were related to mediators of atherosclerosis in a diabetic study. Plasma Lp-PLA2 activity (taken in men only) and A379V genotype were investigated with regards to metabolic syndrome (MS), UKPDS risk score, and oxidised LDL (oxLDL/LDL), in a cohort of Caucasian men and women (n=783, age 62.5+/-13.7 years). After adjustment for type of diabetes, CHD status, and statin use, those individuals with features defining the MS (WHO guidelines) had higher Lp-PLA2 activity (35.6+/-11.9 nmol/min/ml) compared to those without (33.0+/-10.8 nmol/min/ml) (p=0.02). Quartiles of UKPDS coronary heart disease (CHD) risk score were also positively associated with Lp-PLA2 activity (p=0.006, p=0.004 linear trend). Those men in the highest quartile of oxLDL/LDL level had the lowest Lp-PLA2 activity (31.3+/-10.5 nmol/min/ml) when compared to the middle two (32.3+/-9.8 and 35.9+/-10.9 nmol/min/ml, respectively) and lowest quartile (35.6 +/-12.5 nmol/min/ml; p=0.03, p=0.004 linear trend). There was no significant association between A379V genotype and Lp-PLA2 enzyme activity (p=0.34) or oxLDL/LDL (p=0.32). Lp-PLA2 activity is an independent predictor of CHD risk and MS in a sample of subjects with diabetes mellitus. The association of Lp-PLA2 activity with oxLDL/LDL suggests that Lp-PLA2 may be a modulating factor in the process of atherosclerosis.

The significant increase in cardiovascular disease risk in APOEepsilon4 carriers is evident only in men who smoke: potential relationship between reduced antioxidant status and ApoE4.

Data from 1668 men (316 cardiovascular disease events) from the Framingham Offspring Study was reanalysed, specifically examining APOE:smoking interactions. Overall hazard ratio (HR) for smoking was 1.95 (1.52, 2.50) compared to non-smokers. Using epsilon3/3 as a referent group, in non-smokers HRs for epsilon2 carriers (epsilon2+; 1.04 (0.61, 1.76) and epsilon4 carriers (epsilon4+; 1.04 (0.70, 1.54) showed no major risk increase. In smokers, HRs were 1.96 (1.26, 2.78) in epsilon3epsilon3 men, 3.46 (2.14, 5.60; p = 0.09 for interaction) in epsilon2+ and 3.81 (2.49, 5.84; p = 0.01 for interaction), with a significant interaction between daily cigarette consumption and APOE genotype on risk (p = 0.03). The potential mechanism for this APOEepsilon4:smoking interaction was examined in a second study of 728 Caucasian patients with diabetes, where markers of reactive oxygen species were available. APOE genotype was not associated with plasma OX-LDL or total antioxidant status (TAOS) in non-smokers. However, in smokers epsilon4+ had 26.7% higher plasma OX-LDL than other genotypes (APOE:smoking interaction p = 0.04), while epsilon2+ had 28.4% higher plasma TAOS than epsilon3epsilon3 and epsilon4+ combined (APOE:smoking interaction p = 0.026). Although direct extrapolation needs to be considered with caution, these results identify that the cardiovascular disease risk-raising effect of epsilon4+ is confined to smokers, and a feasible mechanism is presented by the reduced antioxidant capacity/increased OX-LDL of apoE4.

APOE polymorphism, socioeconomic status and cognitive function in mid-life--the Whitehall II longitudinal study.

OBJECTIVE: The aim of this study was to investigate the association of the common apolipoprotein E gene (APOE) variants with cognitive function and cognitive decline in adult mid-life and explore the possibility that APOE genotype mediates the link between socioeconomic status (SES) and cognitive function. METHODS: Data on cognitive function, as measured by five cognitive tests, together with APOE genotype were obtained in an occupational cohort (the Whitehall II study) of 6,004 participants aged 44-69 years (1997-1999). Cognitive change was examined in 2,717 participants who had cognitive function measured at baseline (1991-1993). RESULTS: SES based on civil service employment grade was strongly related to cognitive function. There was no association between APOE genotype and employment grade. In women, participants with APOE-epsilon4 had a lower memory score (p<0.05), but the result was sensitive to data from a small number of individuals. A marginal cross-sectional difference in the semantic fluency score was found (p=0.07), and there was a relative decline at follow-up (p<0.001, net change=-1.19; 95% CI, -1.90 to -0.49) in those with APOE-epsilon4 genotypes. CONCLUSIONS: APOE-epsilon4 has little influence on cognitive decline in mid-life, whereas SES is a strong determinant, although APOE genotype may emerge as an important factor in cognitive function in later life.

Cholesteryl ester transfer protein TaqIB variant, high-density lipoprotein cholesterol levels, cardiovascular risk, and efficacy of pravastatin treatment: individual patient meta-analysis of 13,677 subjects.

BACKGROUND: Several studies have reported that the cholesteryl ester transfer protein (CETP) TaqIB gene polymorphism is associated with HDL cholesterol (HDL-C) levels and the risk of coronary artery disease (CAD), but the results are inconsistent. In addition, an interaction has been implicated between this genetic variant and pravastatin treatment, but this has not been confirmed. METHODS AND RESULTS: A meta-analysis was performed on individual patient data from 7 large, population-based studies (each >500 individuals) and 3 randomized, placebo-controlled, pravastatin trials. Linear and logistic regression models were used to assess the relation between TaqIB genotype and HDL-C levels and CAD risk. After adjustment for study, age, sex, smoking, body mass index (BMI), diabetes, LDL-C, use of alcohol, and prevalence of CAD, TaqIB genotype exhibited a highly significant association with HDL-C levels, such that B2B2 individuals had 0.11 mmol/L (0.10 to 0.12, P<0.0001) higher HDL-C levels than did B1B1 individuals. Second, after adjustment for study, sex, age, smoking, BMI, diabetes, systolic blood pressure, LDL-C, and use of alcohol, TaqIB genotype was significantly associated with the risk of CAD (odds ratio=0.78 [0.66 to 0.93]) in B2B2 individuals compared with B1B1 individuals (P for linearity=0.008). Additional adjustment for HDL-C levels rendered a loss of statistical significance (P=0.4). Last, no pharmacogenetic interaction between TaqIB genotype and pravastatin treatment could be demonstrated. CONCLUSIONS: The CETP TaqIB variant is firmly associated with HDL-C plasma levels and as a result, with the risk of CAD. Importantly, this CETP variant does not influence the response to pravastatin therapy.

Heritability of C-reactive protein and association with apolipoprotein E genotypes in Japanese Americans.

Numerous studies have demonstrated that increased C-reactive protein (CRP) levels predict coronary heart disease, stroke, peripheral vascular disease, and diabetes, and are associated with features of the metabolic syndrome. Only three previous studies have investigated the heritability of CRP levels, primarily in samples of Caucasian families. The purpose of the present study was to estimate the magnitude of genetic influences on CRP levels, and to examine potential associations between variation in the APOE gene and CRP levels, using a sample of 562 individual Japanese Americans from 68 extended kindreds. In general, correlation coefficients between first-degree relatives for CRP were approximately 0.2, and spouse correlations did not differ from zero, consistent with genetic influences. Heritability estimates were approximately 0.3 (p < 0.01), even with adjustment for factors known to influence CRP levels. A significant relationship was seen between unadjusted CRP levels and APOE genotypes (p = 0.02), with the highest mean CRP level among epsilon2 carriers (1.20 mg/L), and nearly the same mean levels among epsilon3/epsilon3 subjects and epsilon4 carriers (0.72 and 0.74 mg/L, respectively). However, this relationship was diminished with adjustment for covariates (p = 0.07). These results demonstrate the presence of both genetic and environmental effects on CRP levels among Asian Americans, and additional studies are needed to determine if the APOE gene contributes to these genetic influences.