Plasma protein S (PS) levels are reportedly low in patients with venous thrombosis but high in coronary heart disease (CHD) patients. The authors examined the association between free PS concentration and CHD or stroke risk and assessed risk in combination with C-reactive protein (CRP) levels. Free PS concentration was determined in 6 annual visits among 3,052 middle-aged (49–64 years) United Kingdom men from the Second Northwick Park Heart Study, with 297 CHD events from 1989 to 2005. The highest (vs. first) quintile was associated with a significantly increased CHD risk after adjustment for all other risk factors and correction for regression dilution bias (hazard ratio = 1.85, 95% confidence interval: 1.08, 3.16; P = 0.024). Models that included all well-known risk factors plus PS quintiles improved prediction of CHD (net reclassification improvement (NRI) = 7.0% (P = 0.007), category-less NRI (>0) = 22.1% (P < 0.001)), and the likelihood ratio statistic increased significantly (P = 0.018). The increase in CHD risk was particularly strong when subjects also had high CRP levels. There was no association between free PS level and stroke risk. This study confirms the independent association of elevated free PS levels with future risk of CHD, although elevated PS levels added only modestly to prediction metrics. The novel finding of increased CHD risk, particularly when CRP and PS levels are high, requires further study.
coronary disease; inflammation; protein S; risk factors; stroke
Cardiovascular disease and diabetes have been linked to shorter telomeres, but it is not yet clear which risk factors contribute to shorter telomeres in patients. Our aim was to examine whether pro-inflammatory conditioning, in combination or not with high glucose, result in a higher rate of telomere shortening during in vitro cellular ageing. Human fibroblasts from four donors were cultured for 90 days in: 1) medium lacking ascorbic acid only, 2) 10 mM buthionine sulphoximine (BSO) (pro-oxidant), 3) 25 mM D-glucose, 4) 1 ng/ml IL1B and 5) 25 mM D-glucose+1 ng/ml IL1B. Telomere length was measured with qPCR and intracellular reactive oxygen species (ROS) content and cell death with flow cytometry. Cultures treated with high glucose and BSO displayed a significantly lower growth rate, and cultures treated with IL1B showed a trend towards a higher growth rate, compared to the control [Glucose:0.14 PD/day, p<0.001, BSO: 0.11 PD/day, p = 0.006 and IL1B: 0.19 PD/day, p = 0.093 vs. Control:0.16 PD/day]. Telomere shortening with time was significantly accelerated in cultures treated with IL1B compared to the control [IL1B:−0.8%/day (95%CI:−1.1, −0.5) vs. Control:−0.6%/day (95%CI:−0.8, −0.3), p = 0.012]. The hastening of telomere shortening by IL1B was only in part attenuated after adjustment for the number of cell divisions [IL1B:−4.1%/PD (95%CI:−5.7, −2.4) vs. Control:−2.5%/PD (95%CI:−4.4, −0.7), p = 0.067]. The intracellular ROS content displayed 69% increase (p = 0.033) in BSO compared to the control. In aging fibroblasts, pro-inflammatory conditioning aggravates the shortening of telomeres, an effect which was only in part driven by increased cell turnover. High glucose alone did not result in greater production of ROS or telomere shortening.
The first aim was to critically evaluate the extent to which familial hypercholesterolaemia (FH) is underdiagnosed and undertreated. The second aim was to provide guidance for screening and treatment of FH, in order to prevent coronary heart disease (CHD).
Methods and results
Of the theoretical estimated prevalence of 1/500 for heterozygous FH, <1% are diagnosed in most countries. Recently, direct screening in a Northern European general population diagnosed approximately 1/200 with heterozygous FH. All reported studies document failure to achieve recommended LDL cholesterol targets in a large proportion of individuals with FH, and up to 13-fold increased risk of CHD. Based on prevalences between 1/500 and 1/200, between 14 and 34 million individuals worldwide have FH. We recommend that children, adults, and families should be screened for FH if a person or family member presents with FH, a plasma cholesterol level in an adult ≥8 mmol/L(≥310 mg/dL) or a child ≥6 mmol/L(≥230 mg/dL), premature CHD, tendon xanthomas, or sudden premature cardiac death. In FH, low-density lipoprotein cholesterol targets are <3.5 mmol/L(<135 mg/dL) for children, <2.5 mmol/L(<100 mg/dL) for adults, and <1.8 mmol/L(<70 mg/dL) for adults with known CHD or diabetes. In addition to lifestyle and dietary counselling, treatment priorities are (i) in children, statins, ezetimibe, and bile acid binding resins, and (ii) in adults, maximal potent statin dose, ezetimibe, and bile acid binding resins. Lipoprotein apheresis can be offered in homozygotes and in treatment-resistant heterozygotes with CHD.
Owing to severe underdiagnosis and undertreatment of FH, there is an urgent worldwide need for diagnostic screening together with early and aggressive treatment of this extremely high-risk condition.
Cholesterol; Low-density lipoprotein; Atherosclerosis; Coronary heart disease; Cardiovascular disease
Familial hypercholesterolemia (FH) is an autosomal dominant disease caused by mutations in the genes coding for the low density lipoprotein receptor (LDLR), proprotein convertase subtilisin/kexin type-9 (PCSK9) or apo-lipoprotein B-100 (APOB). The aim of the present work was to determine the genetic basis of dyslipidemia in 11 unrelated Pakistani families.
High resolution melting (HRM), sequencing and restriction fragment length polymorphism (RFLP).
Probands were screened for the promoter and all coding regions, including intron/exon boundaries, of LDLR and PCSK9 and part of exon 26 of APOB including p.(R3527Q). Two families were identified with previously unreported LDLR mutations (c.1019_1020delinsTG, p.(C340L) and c.1634G>A, p.(G545E)). Both probands had tendon xanthomas or xanthelasma and/or a history of cardiovascular disease. Co-segregation with hypercholesterolemia was demonstrated in both families. In silico studies predicted these variations to be damaging. In two families, novel PCSK9 variations were identified (exon2; c.314G > A, p.(R105Q) and exon3; c.464C>T, p.(P155L)). In silico studies suggested both were likely to be damaging, and family members carrying the p.(105Q) allele had lower total cholesterol levels, suggesting this is a loss-of-function mutation. For c.464C>T p.(P155L) the small number of relatives available precluded any strong inference.
This report brings to seven the number of different LDLR mutations reported in FH patients from Pakistan and, as expected in this heterogeneous population, no common LDLR mutation has been identified.
•We examined the LDLR/PCSK9 genes in patients with FH from Pakistan.•Two novel LDLR mutations both showed co-segregation with hypercholesterolemia.•Two novel PCSK9 variations were found one of which was a loss of function mutation.•This brings to 7 the number of molecular causes of FH in patients from Pakistan.
Familial hypercholesterolemia; LDLR; PCSK9; Xanthomas; HRM; Consanguinity
The role of common APOE variants on plasma lipids, particularly low density lipoprotein (LDL) levels, and coronary heart disease (CHD) risk is well known; the influence of variation in the other nearby apolipoprotein genes APOC1, APOC4 and APOC2 is unclear. This study examines the association between APOE/C1/C4/C2 gene cluster variation using tagging SNPs and plasma lipid concentration along with risk of CHD in a prospective cohort. Genotypes for 11 common APOE/C1/C4/C2 SNPs were determined in 2,767 middle-aged (49 to 64 years) men from the Second Northwick Park Heart Study, with 275 CHD events over a 15-year follow-up period. Seven SNPs showed significant associations with one or more lipid trait in univariate analysis. Multivariate and haplotype analysis showed that the APOE genotypes are most strongly associated with effects on LDL-C and apoB concentration (explaining 3.4% of the LDL-C variance) while the other SNPs in this gene cluster explained an additional 1.2%. Haplotypes in APOC2 and APOC4 were associated with modest effects on HDL-C and apoAI (explaining respectively 1.4% and 1.2%). Carriers of the APOE ɛ2 SNP had a significantly lower risk of CHD hazard ratio (HR) of 0.63 (95% confidence interval [CI]: 0.42–0.95), as did carriers of the APOC2 SNP rs5127 (HR = 0.72, 95% CI: 0.56–0.93), while carriers of APOC1 SNP rs4803770 had higher risk of CHD (HR = 1.36, 95% CI: 1.04–1.78) compared with noncarriers. While the common APOE polymorphism explains the majority of the locus genetic determinants of plasma lipid levels, additional SNPs in the APOC1/C2 region may contribute to CHD risk, but these effects require confirmation.
Objectives: To determine any association between serum paraoxonase-1 (PON1) activity, protein and coding region genetic polymorphisms and coronary artery calcification (CACS) and to determine factors which modulate serum PON1 in type 2 diabetes (T2DM).
Methods and results: 589 patients (419 Caucasian, 120 South Asian, 50 other) from the PREDICT Study were investigated. All patients were asymptomatic for coronary disease and had established T2DM. CACS, lipids, lipoproteins, inflammatory markers, insulin resistance and PON1 activity, concentration and Q192R and L55M genotypes were measured. Independent associations were: 1) PON1 activity negatively with insulin resistance, triglycerides and PON1-55 genotype and positively with PON1-192 genotype; 2) PON1 concentration negatively with Caucasian ethnicity, duration of diabetes and statin use and positively with plasma creatinine and PON1-192 genotype. There was no association between CACS and any of the PON1 activity, concentration or genotype and this finding was not different in the various ethnic groups within the PREDICT study.
Conclusion: PON1 is modulated by a number of factors, some of which are reported here for the first time, including ethnicity and insulin resistance in subjects with T2DM. No association between CACS and PON1 was found.
Paraoxonase-1; coronary calcification; insulin resistance; Type 2 diabetes
To assess the relationship of levels of inflammatory risk markers to presence of clinical coronary artery disease (CAD) in patients with treated heterozygous familial hypercholesterolaemia.
A cross-sectional study of patients on the Simon Broome Familial Hyperlipidaemia Register.
Six hospital outpatient clinics in the UK.
A total of 211 men and 199 women with heterozygous familial hypercholesterolaemia.
Main outcome measures
Analysis of conventional risk factors and concentrations of high-sensitivity C-reactive protein (hsCRP), lipoprotein(a), serum intercellular adhesion molecule (sICAM), interleukin-6 (IL-6) and lipoprotein-associated phospholipase A2 (LpPLA2) mass.
CAD was present in 104 men and in 55 women; the mean ages of onset were 43.1 and 46.5 years, respectively. On univariate analysis there was a positive relationship of CAD with age, male sex, smoking, IL-6 and sICAM, and an inverse relationship with low-density lipoprotein (LDL) and LpPLA2. On multivariate analysis, age, smoking, low LDL and low LpPLA2 were associated with CAD. When LpPLA2 values were adjusted for apoB and aspirin usage, there was no significant difference between those with and without CAD. Only age and smoking were independently associated with CAD in men, and IL-6 and lipoprotein(a) in women.
Although on univariate analysis inflammatory marker levels were associated with CAD in these patients, the majority of the associations, including that for hsCRP, disappeared when corrected for smoking and apoB. This may be because atherosclerotic plaques in these statin-treated patients were quiescent or an effect of aspirin usage. In this observational study newer risk markers were not usefully associated with the presence or absence of symptomatic CAD.
PPAR-γ co-activator-1α (PGC-1α) is a tissue-specific transcriptional co-activator involved in the regulation of antioxidant enzymes. The A-allele of the rs8192678 PGC-1 α} (G>A) gene variant has previously been associated with nephropathy in Korean and Indian-Asian type 2 diabetes mellitus (T2DM) samples. Our aim was to examine the association between this variant and urine albumin exccretion in European subjects with T2DM. Genotyping was performed on 583 European subjects with T2DM and examined in relation to urinary albumin, plasma oxidized-LDL and small dense-LDL percentage. We observed a significant association between genotype (GG/GA/AA) and urinary albumin (normoalbuminuria v micro/macroalbuminuria: 48.6/39.7/11.7% v 38.2/51.2/10.5%, p=0.02; for GG v GA/AA, p=0.01). The odds ratio for micro/macroalbuminuria in GA and AA subjects relative to GG were 1.70 [1.15–2.50], p=0.008 and 1.20 [0.66–2.16], p=0.56 respectively (for GA/AA v GG: 1.58 [95% CI: 1.09–2.27], p=0.02). There was a significant association between the A allele and a higher percentage of small dense-LDL particles (GG v GA v AA: 70.8 [58.01–81.06] % v 72.8 [56.18–81.19] % v 78.9 [67.16–85.33] %, p=0.03). In European subjects with T2DM the GA relative to the GG genotype is associated with a 70% increase in the risk of micro/microalbuminuria. Furthermore, homozygosity for the A-allele is also associated with a preponderance of small dense-LDL particles.
PGC-1α; type 2 diabetes mellitus; microalbuminuria; oxidative stress
Abdominal aortic aneurysm (AAA) is a common disease with a large heritable component. There is a need to improve our understanding of AAA pathogenesis in order to develop novel treatment paradigms. Genomewide association studies have revolutionized research into the genetic variants that underpin the development of many complex diseases including AAA. This article reviews the progress that has been made to date in this regard, including mechanisms by which loci identified by GWAS may contribute to the development of AAA. It also highlights potential post-GWAS analytical strategies to improve our understanding of the disease further.
Evidence for the associations of single nucleotide polymorphisms (SNPs) in the F7 gene and factor VII (FVII) levels and with risk of coronary heart disease (CHD) is inconsistent. We examined whether F7 tagging SNPs and haplotypes were associated with FVII levels, coagulation activation markers (CAMs) and CHD risk in two cohorts of UK men.
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.
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, while the minor allele for two SNPs (I/D323, and rs6046; haplotype H5) were associated with lower levels. Adjusted for classical risk factors, H2 carriers had a CHD Hazard Ratio of 1.34 (CI 95%: 1.12–1.59; independent of FVIIc), while H5 carriers had a CHD-risk of 1.29 (CI 95%: 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 association of H5 with higher CHD-risk (pooled-estimate OR 1.16 [1.00–1.36], P=0.05), but surprisingly, H2 exhibited a reduced risk for CHD.
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, while the haplotype associated with high FVIIc level was not.
Factor VII; F7 gene; tagging SNPs; haplotypes; incident coronary heart disease
Previous studies suggest that circulating levels of interleukin-18 (IL-18) may be prospectively related to risk of coronary heart disease (CHD) in the general population. We report new data from the largest prospective study to date, which are combined with data from all published prospective studies in a meta-analysis.
We measured baseline IL-18 levels in stored serum samples of subjects from a case–control study nested within a prospective study of 5661 men aged 40–59 years recruited from general practices in 18 British towns in 1978–1980 and followed-up for up to 16 years (median time to event 8.4 years) for fatal CHD and non-fatal myocardial infarction (595 cases, 1238 controls).
IL-18 concentrations were strongly related to cigarette smoking, triglyceride, HDL-cholesterol (inversely) and to circulating levels of several inflammatory and haemostatic markers. Men in the top third of baseline IL-18 levels had an age-adjusted odds ratio (OR) for CHD of 1.55 (95% CI 1.21, 1.98) compared with those in the lowest third; this was reduced to 1.30 (95% CI 0.99, 1.69) after additional adjustment for vascular risk factors and 1.12 (95% CI 0.84, 1.49) after further adjustment for CRP and IL-6. In meta-analyses of CVD, associations (or effect sizes) were consistent between studies; RRs were 1.63 (95% CI 1.46, 1.82) after age adjustment, 1.39 (95% CI 1.24, 1.55) after additional risk factor adjustment and 1.34 (95% CI 1.17, 1.54) after additional adjustment for inflammatory markers.
Circulating IL-18 is prospectively and independently associated with CVD risk.
Coronary heart disease; Epidemiology; Interleukin-18; Cohort; Meta-analysis
A sequence variant, rs7025486[A], in DAB2IP on chromosome 9q33 has recently been associated with coronary heart disease (CHD). We sought to replicate this finding and to investigate associations with a panel of inflammatory and haemostatic biomarkers. We also sought to examine whether this variant, in combination with a chromosome 9p21 CHD variant (rs10757278) and the Framingham risk score (FRS), could improve the prediction of events compared with the FRS alone.
Methods and results
rs7025486 was genotyped in 1386 CHD cases and 3532 controls and was associated with CHD [odds ratio (OR) of 1.16, 95% confidence interval (CI) 1.05–1.29, P= 0.003]. Meta-analysis, using data from the original report and from genome-wide association studies in both the Wellcome Trust Case Control Consortium and the Cardiovascular Health Study, comprising 9968 cases and 20 048 controls, confirmed the association (OR of 1.10, 95% CI 1.06–1.14, P= 3.2 × 10−6). There was no association with a panel of CHD biomarkers, including any lipid, inflammation, or coagulation trait, nor with telomere length. Addition to the FRS of this variant plus rs10757278 on chromosome 9p21 improved the area under the receiver-operating characteristic curve (AROC) from 0.61 to 0.64 (P= 0.03) as well as improving the reclassification (net reclassification index = 11.1%, P= 0.007).
This study replicates a previous association of a variant in DAB2IP with CHD. Addition of multiple variants improves the performance of predictive models based upon classical cardiovascular risk factors.
DAB2IP; Coronary heart disease; Genetic; Single-nucleotide polymorphism; Genomics
Familial hypercholesterolaemia is one of the most common dominantly inherited disorders to be identified in primary care, leading to raised serum cholesterol evident from the first year of life. Around 1 in 500 people are affected by this condition, but less than 15% of these are currently attending lipid clinics, suggesting that the vast majority are unrecognised in general practice. The recently released National Institute for Health and Clinical Excellence evidence-based guideline on the identification and management of familial hypercholesterolaemia provides an opportunity to bridge this gap. Primary care has a role in systematic and opportunistic case finding, such as recognising the relevance of a family history of premature coronary heart disease and/or grossly elevated cholesterol. Although affected individuals need specialist care, GPs can reinforce the information provided by specialists and support cascade screening to other affected members of the extended family.
family health; familial hypercholesteroaemia; family health; medical genetics; primary health care
Genome-wide association studies have proved very successful in identifying novel single-nucleotide polymorphisms (SNPs) associated with disease or traits, but the related, functional SNP is usually unknown. In this paper, we describe a methodology to locate and validate candidate functional SNPs using lipoprotein lipase (LPL), a gene previously associated with triglyceride levels, as an exemplar. Two thousand seven hundred and eighty-six healthy middle-aged men from the NPHSII UK prospective study (with up to six measures of plasma lipid levels) were genotyped for 20 LPL tagging (t)SNPs using Illumina Bead technology. Using model-selection procedures and haplotypes, we identified eight SNPs that consistently maximized the fit of the model to the phenotype. Fifteen SNPs in high linkage disequilibrium with these were identified, and functional assays were carried out on all 23 SNPs. Electrophoretic mobility shift assay (EMSA) was used to identify SNPs that had the potential to alter DNA–protein interactions, reducing the number to eight possible candidate SNPs. These were examined for ability to alter expression using a luciferase reporter assay, and two regulatory SNPs, showing genotype differences, rs327 and rs3289, were identified. Finally, multiplexed-competitor-EMSA (MC-EMSA) and supershift EMSA identified FOXA2 to rs327T, and CREB-binding protein (CBP) and CCAAT displacement protein (CDP) to rs3289C as the factors responsible for transcription binding. We have identified two novel candidate functional SNPs in LPL and presented a procedure aimed to efficiently detect SNPs potentially causal to genetic association. We believe that this methodology could be successfully applied to future re-sequencing data.
Cholesteryl ester transfer protein (CETP) inhibitors raise HDL-cholesterol but torcetrapib, the first-in-class inhibitor tested in a large outcome trial caused unexpected blood pressure elevation and increased cardiovascular events. Whether the hypertensive effect resulted from CETP-inhibition or an off-target action of torcetrapib has been debated. We hypothesised that common single nucleotide polymorphisms (SNPs) in the CETP-gene could help distinguish mechanism-based from off-target actions of CETP-inhibitors to inform on the validity of CETP as a therapeutic target.
Methods and Results
We compared the effect of CETP SNPs and torcetrapib treatment on lipid fractions, blood pressure and electrolytes in up to 67,687 individuals from genetic studies and 17,911 from randomised trials. CETP SNPs and torcetrapib treatment reduced CETP activity and had directionally concordant effect on eight lipid and lipoprotein traits (total-, LDL- and HDL-cholesterol, HDL2, HDL3, apolipoproteins A-I, -B, and triglycerides), with the genetic effect on HDL-cholesterol (0.13 mmol/L; 95% CI: 0.11, 0.14) being consistent with that expected of a 10 mg dose of torcetrapib (0.13 mmol/L; 0.10, 0.15). In trials, 60mg torcetrapib elevated systolic and diastolic blood pressure by 4.47mmHg (4.10, 4.84) and 2.08mmHg (1.84, 2.31) respectively. However, the effect of CETP SNPs on systolic 0.16mmHg (−0.28, 0.60) and diastolic blood pressure −0.04mmHg (−0.36, 0.28) was null and significantly different from that expected of 10 mg torcetrapib.
Discordance in the effects of CETP SNPs and torcetrapib treatment on blood pressure despite the concordant effects on lipids indicates the hypertensive action of torcetrapib is unlikely to be due to CETP-inhibition, or shared by chemically dissimilar CETP inhibitors. Genetic studies could find use in drug development programmes as a new source of randomised evidence for drug target validation in man.
genetics; pharmacology; epidemiology
Shorter telomeres have been reported in premature myocardial infarction (MI) patients. Our work aimed at confirming the association of shorter telomere with MI in two case–control studies and in familial hypercholesterolemia (FH) patients with coronary heart disease (CHD). The HIFMECH study compared 598 white male patients (<60 years) who survived a first MI and 653 age-matched controls from North and South Europe. Additionally, from the UK, 413 coronary artery bypass graft (CABG) patients and two groups of 367 and 94 FH patients, of whom 145 and 17 respectively had premature CHD, were recruited. Leukocyte telomere length (LTL) was measured using a real-time polymerase chain reaction-based method. In HIFMECH, LTL was significantly shorter in subjects from the North (7.99 kb, SD 4.51) compared to the South (8.27 kb, SD 4.14; p = 0.02) and in cases (7.85 kb, SD 4.01) compared to controls (8.04 kb, SD 4.46; p = 0.04). In the CABG study, LTL was significantly shorter (6.89 kb, SD 4.14) compared to the HIFMECH UK controls (7.53, SD 5.29; p = 0.007). In both samples of FH patients, LTL was shorter in those with CHD (overall 8.68 kb, SD 4.65) compared to the non-CHD subjects (9.23 kb, SD 4.83; p = 0.012). Apart from a consistent negative correlation with age, LTL was not associated across studies with any measured CHD risk factors. The present data confirms that subjects with CHD have shorter telomeres than controls and extends this to those with monogenic and polygenic forms of CHD.
Electronic supplementary material
The online version of this article (doi:10.1007/s00109-010-0624-3) contains supplementary material, which is available to authorized users.
Telomere length; Myocardial infarction; Coronary artery bypass grafting (CABG); Familial hypercholesterolemia (FH)
High oxidative stress potentially leads to accelerated telomere shortening and consequent premature cell senescence, implicated in type 2 diabetes (T2D) development. Therefore, we studied the association of leukocyte telomere length (LTL) with the presence of T2D, as well as the effect on the patients’ LTL of plasma oxidative stress and of variation in UCP2, a gene involved in the mitochondrial production of reactive oxygen species.
Mean LTL was determined in 569 Caucasian, 103 South Asian and 70 Afro-Caribbean T2D patients aged from 24 to 92 years, 81 healthy Caucasian male students aged from 18 to 28 years and 367 healthy Caucasian men aged from 40 to 61 years by real-time PCR. Plasma total antioxidant status (TAOS) was measured in the T2D patients by a photometric microassay. The patients were also genotyped for the UCP2 functional variants −866G>A and A55V.
Afro-Carribeans had 510 bp longer mean length compared to Caucasians (p < 0.0001) and 500 bp longer than South Asians (p = 0.004). T2D subjects displayed shorter age-adjusted LTL compared to controls [6.94(6.8–7.03) vs. 7.72(7.53–7.9), p < 0.001] with subjects in the middle and the lowest tertile of LTL having significantly higher odds ratios for T2D compared to those in the highest tertile [1.50(1.08–2.07) and 5.04(3.63–6.99), respectively, p < 0.0001]. In the patients, LTL was correlated negatively with age (r = −0.18, p < 0.0001) and positively with TAOS measures (r = 0.12, p = 0.01) after adjusting for age, while carriers of the UCP2 −866A allele had shorter age-adjusted LTL than common homozygotes [6.86(6.76–6.96) kb vs. 7.03(6.91–7.15) kb, p = 0.04].
The present data suggest that shorter LTL is associated with the presence of T2D and this could be partially attributed to the high oxidative stress in these patients. The association of the UCP2 functional promoter variant with the LTL implies a link between mitochondrial production of reactive oxygen species and shorter telomere length in T2D.
Telomere length; Type 2 diabetes; Oxidative stress; UCP2 gene; Ethnic diversity
Telomere length; Cardiovascular disease; Diabetes; Oxidative stress
Background Non-uniform reporting of relevant relationships and metrics hampers critical appraisal of the clinical utility of C-reactive protein (CRP) measurement for prediction of later coronary events.
Methods We evaluated the predictive performance of CRP in the Northwick Park Heart Study (NPHS-II) and the Edinburgh Artery Study (EAS) comparing discrimination by area under the ROC curve (AUC), calibration and reclassification. We set the findings in the context of a systematic review of published studies comparing different available and imputed measures of prediction. Risk estimates per-quantile of CRP were pooled using a random effects model to infer the shape of the CRP-coronary event relationship.
Results NPHS-II and EAS (3441 individuals, 309 coronary events): CRP alone provided modest discrimination for coronary heart disease (AUC 0.61 and 0.62 in NPHS-II and EAS, respectively) and only modest improvement in the discrimination of a Framingham-based risk score (FRS) (increment in AUC 0.04 and –0.01, respectively). Risk models based on FRS alone and FRS + CRP were both well calibrated and the net reclassification improvement (NRI) was 8.5% in NPHS-II and 8.8% in EAS with four risk categories, falling to 4.9% and 3.0% for 10-year coronary disease risk threshold of 15%. Systematic review (31 prospective studies 84 063 individuals, 11 252 coronary events): pooled inferred values for the AUC for CRP alone were 0.59 (0.57, 0.61), 0.59 (0.57, 0.61) and 0.57 (0.54, 0.61) for studies of <5, 5–10 and >10 years follow up, respectively. Evidence from 13 studies (7201 cases) indicated that CRP did not consistently improve performance of the Framingham risk score when assessed by discrimination, with AUC increments in the range 0–0.15. Evidence from six studies (2430 cases) showed that CRP provided statistically significant but quantitatively small improvement in calibration of models based on established risk factors in some but not all studies. The wide overlap of CRP values among people who later suffered events and those who did not appeared to be explained by the consistently log-normal distribution of CRP and a graded continuous increment in coronary risk across the whole range of values without a threshold, such that a large proportion of events occurred among the many individuals with near average levels of CRP.
Conclusions CRP does not perform better than the Framingham risk equation for discrimination. The improvement in risk stratification or reclassification from addition of CRP to models based on established risk factors is small and inconsistent. Guidance on the clinical use of CRP measurement in the prediction of coronary events may require updating in light of this large comparative analysis.
C-reactive protein; prediction; coronary heart disease; primary prevention; risk stratification
Background and Purpose
Atherosclerosis is a complex disorder with hereditary and environmental causes. Carotid artery intima-media wall thickness (IMT) is a useful measure of atherosclerosis. The objective of this study was to determine the association between carotid IMT and functional promoter variants of stromelysin-1 (MMP3: −1612 5A>6A), interleukin-6 (IL6: −174G>C), and hepatic lipase (HL: −480C>T) genes.
B-mode carotid ultrasound was performed among 87 subjects (mean age, 70 ± 12 years; 55% women; 60% Caribbean-Hispanic, 25% black, and 13% white) from the Northern Manhattan Prospective Cohort Study. Carotid IMT was calculated as a composite measure (mean of the maximum IMT in the bifurcation, the common carotid artery, and the internal carotid artery).
For all polymorphisms, genotype distribution was not significantly different from Hardy-Weinberg equilibrium. The frequencies of the rare alleles were as follows: MMP3 −1612 5A>6A, 0.31 (95% CI, 0.25 to 0.39); IL6 −174 G>C, 0.20 (95% CI, 0.13 to 0.25); and HL −480 C>T, 0.45 (95% CI, 0.35 to 0.50). Carotid IMT in the sample was 0.78±0.18 mm. Subjects with the MMP3 genotype 6A6A had 8% greater mean carotid IMT than the other MMP3 genotypes combined (0.95±0.17 versus 0.87±0.15 mm; P=0.04). Subjects with the IL6 genotype GG had 11% greater IMT (0.85±0.17 versus 0.76±0.16 mm; P=0.03), and those with the HL genotype CC had 13% greater IMT (0.87±20 versus 0.76±0.18 mm; P=0.02) than the other genotypes combined. Adjustment for other risk factors did not change these associations.
Carotid IMT is higher among subjects homozygous for functional variants in genes related to matrix deposition (MMP3 −16126A), inflammation (IL6 −174G), and lipid metabolism (HL −480C). These associations were independent of race-ethnicity and some environmental exposures. Further studies are needed to confirm these genotype-phenotype associations.
genetics; interleukin-6; intima-media thickness; lipase; stromelysin 1; ultrasonography
Individuals at risk of coronary heart disease (CHD) show multiple correlations across blood biomarkers. Single nucleotide polymorphisms (SNPs) indexing biomarker differences could help distinguish causal from confounded associations because of their random allocation prior to disease. We examined the association of 948 SNPs in 122 candidate genes with 12 CHD-associated phenotypes in 2775 middle aged men (a genic scan). Of these, 140 SNPs indexed differences in HDL- and LDL-cholesterol, triglycerides, C-reactive protein, fibrinogen, factor VII, apolipoproteins AI and B, lipoprotein-associated phospholipase A2, homocysteine or folate, some with large effect sizes and highly significant P-values (e.g. 2.15 standard deviations at P = 9.2 × 10−140 for F7 rs6046 and FVII levels). Top ranking SNPs were then tested for association with additional biomarkers correlated with the index phenotype (phenome scan). Several SNPs (e.g. in APOE, CETP, LPL, APOB and LDLR) influenced multiple phenotypes, while others (e.g. in F7, CRP and FBB) showed restricted association to the index marker. SNPs influencing six blood proteins were used to evaluate the nature of the associations between correlated blood proteins utilizing Mendelian randomization. Multiple SNPs were associated with CHD-related quantitative traits, with some associations restricted to a single marker and others exerting a wider genetic ‘footprint’. SNPs indexing biomarkers provide new tools for investigating biological relationships and causal links with disease. Broader and deeper integrated analyses, linking genomic with transcriptomic, proteomic and metabolomic analysis, as well as clinical events could, in principle, better delineate CHD causing pathways amenable to treatment.
Abdominal aortic aneurysm (AAA) is among a number of vascular disorders to be recently associated with a common allelic variant situated on chromosome 9p21. To further assess the significance of this region of the genome in AAA development, we genotyped the sequence variation tagged by rs10757278 in two geographically independent cohorts of patients and compared them to matched controls. We also assessed the impact of this variant on AAA growth rate in cohorts with a median surveillance period of 3.2 and 4.5 years. Using meta-analysis to combine the findings of both cohorts, we found a significant association between rs10757278-G and the presence of AAA (OR (95%CI) 1.38 (1.04–1.82) P=0.03), an effect size completely consistent with that originally reported. rs10757278 was not significantly associated with altered AAA growth rate in either cohort.
aneurysm; genetic; variant; growth; chromosome 9p21
To examine the changes in coronary, all-cause, and cancer mortality in patients with heterozygous familial hypercholesterolaemia (FH) before and after lipid-lowering therapy with statins.
Methods and results
A total of 3382 patients (1650 men) aged <80 years were recruited from 21 lipid clinics in the United Kingdom and followed prospectively between 1980 and 2006 for 46 580 person-years. There were 370 deaths, including 190 from coronary heart disease (CHD) and 90 from cancer. The standardized mortality ratio (compared with the population in England and Wales) was calculated before and from 1 January 1992. In patients aged 20–79 years, CHD mortality fell significantly by 37% (95% CI = 7–56) from 3.4- to 2.1-fold excess. Primary prevention resulted in a 48% reduction in CHD mortality from 2.0-fold excess to none, with a smaller reduction of nearly 25% in patients with established disease. Coronary mortality was reduced more in women than in men. In patients without known CHD at registration, all-cause mortality from 1992 was 33% (21–43), lower than in the general population, mainly due to a 37% (21–50) lower risk of fatal cancer.
The results emphasize the importance of early identification of FH and treatment with statins.
Familial hypercholesterolaemia; Coronary heart disease; All-cause mortality; Cancer mortality