Whole-exome sequencing in familial type 2 diabetes identifies an atypical missense variant in the RyR2 gene

Genome-wide association studies have identified several hundred loci associated with type 2 diabetes mellitus (T2DM). Additionally, pathogenic variants in several genes are known to cause monogenic diabetes that overlaps clinically with T2DM. Whole-exome sequencing of related individuals with T2DM is a powerful approach to identify novel high-penetrance disease variants in coding regions of the genome. We performed whole-exome sequencing on four related individuals with T2DM - including one individual diagnosed at the age of 33 years. The individuals were negative for mutations in monogenic diabetes genes, had a strong family history of T2DM, and presented with several characteristics of metabolic syndrome. A missense variant (p.N2291D) in the type 2 ryanodine receptor (RyR2) gene was one of eight rare coding variants shared by all individuals. The variant was absent in large population databases and affects a highly conserved amino acid located in a mutational hotspot for pathogenic variants in Catecholaminergic polymorphic ventricular tachycardia (CPVT). Electrocardiogram data did not reveal any cardiac abnormalities except a lower-than-normal resting heart rate (< 60 bpm) in two individuals - a phenotype observed in CPVT individuals with RyR2 mutations. RyR2-mediated Ca2+ release contributes to glucose-mediated insulin secretion and pathogenic RyR2 mutations cause glucose intolerance in humans and mice. Analysis of glucose tolerance testing data revealed that missense mutations in a CPVT mutation hotspot region - overlapping the p.N2291D variant - are associated with complete penetrance for glucose intolerance. In conclusion, we have identified an atypical missense variant in the RyR2 gene that co-segregates with diabetes in the absence of overt CPVT.

Cardiovascular consequences of discontinuing low-dose rivaroxaban in people with chronic coronary or peripheral artery disease

Objective

In patients with chronic coronary or peripheral artery disease enrolled in the Cardiovascular Outcomes for People Using Anticoagulation Strategies trial, randomised antithrombotic treatments were stopped after a median follow-up of 23 months because of benefits of the combination of rivaroxaban 2.5 mg two times per day and aspirin 100 mg once daily compared with aspirin 100 mg once daily. We assessed the effect of switching to non-study aspirin at the time of early stopping.

Methods

Incident composite of myocardial infarction, stroke or cardiovascular death was estimated per 100 person-years (py) during randomised treatment (n=18 278) and after study treatment discontinuation to non-study aspirin (n=14 068).

Results

During randomised treatment, the combination compared with aspirin reduced the composite (2.2 vs 2.9/100 py, HR: 0.76, 95% CI 0.66 to 0.86), stroke (0.5 vs 0.8/100 py, HR: 0.58, 95% CI 0.44 to 0.76) and cardiovascular death (0.9 vs 1.2/100 py, HR: 0.78, 95% CI 0.64 to 0.96). During 1.02 years after early stopping, participants originally randomised to the combination compared with those randomised to aspirin had similar rates of the composite (2.1 vs 2.0/100 py, HR: 1.08, 95% CI 0.84 to 1.39) and cardiovascular death (1.0 vs 0.8/100 py, HR: 1.26, 95% CI 0.85 to 1.86) but higher stroke rate (0.7 vs 0.4/100 py, HR: 1.74, 95% CI 1.05 to 2.87) including a significant increase in ischaemic stroke during the first 6 months after switching to non-study aspirin.

Conclusion

Discontinuing study rivaroxaban and aspirin to non-study aspirin was associated with the loss of cardiovascular benefits and a stroke excess.

Trial registration number

NCT01776424.

Sex-dimorphic genetic effects and novel loci for fasting glucose and insulin variability

Differences between sexes contribute to variation in the levels of fasting glucose and insulin. Epidemiological studies established a higher prevalence of impaired fasting glucose in men and impaired glucose tolerance in women, however, the genetic component underlying this phenomenon is not established. We assess sex-dimorphic (73,089/50,404 women and 67,506/47,806 men) and sex-combined (151,188/105,056 individuals) fasting glucose/fasting insulin genetic effects via genome-wide association study meta-analyses in individuals of European descent without diabetes. Here we report sex dimorphism in allelic effects on fasting insulin at IRS1 and ZNF12 loci, the latter showing higher RNA expression in whole blood in women compared to men. We also observe sex-homogeneous effects on fasting glucose at seven novel loci. Fasting insulin in women shows stronger genetic correlations than in men with waist-to-hip ratio and anorexia nervosa. Furthermore, waist-to-hip ratio is causally related to insulin resistance in women, but not in men. These results position dissection of metabolic and glycemic health sex dimorphism as a steppingstone for understanding differences in genetic effects between women and men in related phenotypes.

Safety and Tolerability of the Chymase Inhibitor Fulacimstat in Patients With Left Ventricular Dysfunction After Myocardial Infarction-Results of the CHIARA MIA 1 Trial

The chymase inhibitor fulacimstat is developed as a first-in-class treatment option for the inhibition of adverse cardiac remodeling in patients with left ventricular dysfunction (LVD) after acute myocardial infarction (MI). The aim of the study was to examine the safety and tolerability of fulacimstat in patients with LVD after remote MI. A multicenter, multinational randomized, placebo-controlled study was performed in clinically stable patients (40-79 years of age, left ventricular ejection fraction ≤ 45% because of MI in medical history) who were on stable evidence-based standard-of-care therapies for LVD post-MI including an angiotensin converting enzyme inhibitor or angiotensin receptor blocker at doses of at least half the recommended target dose. Patients were treated for 2 weeks with either placebo (n = 12) or 4 different doses of fulacimstat (5 mg twice daily, n = 9; 10 mg twice daily, n = 9; 25 mg twice daily, n = 10; 50 mg once daily, n = 9). Fulacimstat was safe and well tolerated at all examined doses. There were no clinically relevant effects on vital signs or potassium levels compared with placebo treatment. Mean plasma concentrations of fulacimstat increased with the administered dose and reached exposures predicted to be therapeutically active. The safety profile and the absence of effects on blood pressure or heart rate in a chronic patient population having similar comorbidities and receiving similar comedication as patients after acute MI support future clinical trials with fulacimstat in patients after acute MI.

Association of myeloperoxidase with total and cardiovascular mortality in individuals undergoing coronary angiography--the LURIC study

Background

The phagocytic enzyme myeloperoxidase (MPO) acts as a front-line defender against microorganisms. However, increased MPO levels have been found to be associated with complex and calcified atherosclerotic lesions and incident cardiovascular disease. Therefore, this study aimed to investigate a predictive role of MPO, a biomarker of inflammation and oxidative stress, for total and cardiovascular mortality in patients referred to coronary angiography.

Methods and results

MPO plasma concentrations along with eight MPO polymorphisms were determined in 3036 participants of the Ludwigshafen Risk and Cardiovascular Health study (median follow-up 7.75 years). MPO concentrations were positively associated with age, diabetes, smoking, markers of systemic inflammation (interleukin-6, fibrinogen, C-reactive protein, serum amyloid A) and vascular damage (vascular cellular adhesion molecule-1 and intercellular adhesion molecule-1) but negatively associated with HDL-cholesterol and apolipoprotein A-I. After adjustment for cardiovascular risk factors MPO concentrations in the highest versus the lowest quartile were associated with a 1.34-fold risk (95% CI: 1.09–1.67) for total mortality. In the adjusted model the hazard ratio for cardiovascular mortality in the highest MPO quartile was 1.42 (95% CI: 1.07–1.88). Five MPO polymorphisms were positively associated with MPO concentrations but not with mortality. Using Mendelian randomization, we did not obtain evidence for a causal association of MPO with either total or cardiovascular mortality.

Conclusions

MPO concentrations but not genetic variants at the MPO locus are independently associated with risk for total and cardiovascular mortality in coronary artery disease patients.

Genome-wide association study for circulating tissue plasminogen activator levels and functional follow-up implicates endothelial STXBP5 and STX2

OBJECTIVE

Tissue plasminogen activator (tPA), a serine protease, catalyzes the conversion of plasminogen to plasmin, the major enzyme responsible for endogenous fibrinolysis. In some populations, elevated plasma levels of tPA have been associated with myocardial infarction and other cardiovascular diseases. We conducted a meta-analysis of genome-wide association studies to identify novel correlates of circulating levels of tPA.

APPROACH AND RESULTS

Fourteen cohort studies with tPA measures (N=26 929) contributed to the meta-analysis. Three loci were significantly associated with circulating tPA levels (P<5.0×10(-8)). The first locus is on 6q24.3, with the lead single nucleotide polymorphism (SNP; rs9399599; P=2.9×10(-14)) within STXBP5. The second locus is on 8p11.21. The lead SNP (rs3136739; P=1.3×10(-9)) is intronic to POLB and <200 kb away from the tPA encoding the gene PLAT. We identified a nonsynonymous SNP (rs2020921) in modest linkage disequilibrium with rs3136739 (r(2)=0.50) within exon 5 of PLAT (P=2.0×10(-8)). The third locus is on 12q24.33, with the lead SNP (rs7301826; P=1.0×10(-9)) within intron 7 of STX2. We further found evidence for the association of lead SNPs in STXBP5 and STX2 with expression levels of the respective transcripts. In in vitro cell studies, silencing STXBP5 decreased the release of tPA from vascular endothelial cells, whereas silencing STX2 increased the tPA release. Through an in silico lookup, we found no associations of the 3 lead SNPs with coronary artery disease or stroke.

CONCLUSIONS

We identified 3 loci associated with circulating tPA levels, the PLAT region, STXBP5, and STX2. Our functional studies implicate a novel role for STXBP5 and STX2 in regulating tPA release.

Meta-analysis of genome-wide association studies identifies six new Loci for serum calcium concentrations

Calcium is vital to the normal functioning of multiple organ systems and its serum concentration is tightly regulated. Apart from CASR, the genes associated with serum calcium are largely unknown. We conducted a genome-wide association meta-analysis of 39,400 individuals from 17 population-based cohorts and investigated the 14 most strongly associated loci in ≤21,679 additional individuals. Seven loci (six new regions) in association with serum calcium were identified and replicated. Rs1570669 near CYP24A1 (P = 9.1E-12), rs10491003 upstream of GATA3 (P = 4.8E-09) and rs7481584 in CARS (P = 1.2E-10) implicate regions involved in Mendelian calcemic disorders: Rs1550532 in DGKD (P = 8.2E-11), also associated with bone density, and rs7336933 near DGKH/KIAA0564 (P = 9.1E-10) are near genes that encode distinct isoforms of diacylglycerol kinase. Rs780094 is in GCKR. We characterized the expression of these genes in gut, kidney, and bone, and demonstrate modulation of gene expression in bone in response to dietary calcium in mice. Our results shed new light on the genetics of calcium homeostasis.

Calcium is vital to many biological processes and its serum concentration is tightly regulated. Family studies have shown that serum calcium is under strong genetic control. Apart from CASR, the genes associated with serum calcium are largely unknown. We conducted a genome-wide association meta-analysis of 39,400 individuals from 17 population-based cohorts and investigated the 14 most strongly associated loci in ≤21,679 additional individuals. We identified seven loci (six new regions) as being robustly associated with serum calcium. Three loci implicate regions involved in rare monogenic diseases including disturbances of serum calcium levels. Several of the newly identified loci harbor genes linked to the hormonal control of serum calcium. In mice experiments, we characterized the expression of these genes in gut, kidney, and bone, and explored the influence of dietary calcium intake on the expression of these genes in these organs. Our results shed new light on the genetics of calcium homeostasis and suggest a role for dietary calcium intake in bone-specific gene expression.

Sex-stratified genome-wide association studies including 270,000 individuals show sexual dimorphism in genetic loci for anthropometric traits

Given the anthropometric differences between men and women and previous evidence of sex-difference in genetic effects, we conducted a genome-wide search for sexually dimorphic associations with height, weight, body mass index, waist circumference, hip circumference, and waist-to-hip-ratio (133,723 individuals) and took forward 348 SNPs into follow-up (additional 137,052 individuals) in a total of 94 studies. Seven loci displayed significant sex-difference (FDR<5%), including four previously established (near GRB14/COBLL1, LYPLAL1/SLC30A10, VEGFA, ADAMTS9) and three novel anthropometric trait loci (near MAP3K1, HSD17B4, PPARG), all of which were genome-wide significant in women (P<5×10(-8)), but not in men. Sex-differences were apparent only for waist phenotypes, not for height, weight, BMI, or hip circumference. Moreover, we found no evidence for genetic effects with opposite directions in men versus women. The PPARG locus is of specific interest due to its role in diabetes genetics and therapy. Our results demonstrate the value of sex-specific GWAS to unravel the sexually dimorphic genetic underpinning of complex traits.

Genome-wide meta-analysis identifies 11 new loci for anthropometric traits and provides insights into genetic architecture

Approaches exploiting trait distribution extremes may be used to identify loci associated with common traits, but it is unknown whether these loci are generalizable to the broader population. In a genome-wide search for loci associated with the upper versus the lower 5th percentiles of body mass index, height and waist-to-hip ratio, as well as clinical classes of obesity, including up to 263,407 individuals of European ancestry, we identified 4 new loci (IGFBP4, H6PD, RSRC1 and PPP2R2A) influencing height detected in the distribution tails and 7 new loci (HNF4G, RPTOR, GNAT2, MRPS33P4, ADCY9, HS6ST3 and ZZZ3) for clinical classes of obesity. Further, we find a large overlap in genetic structure and the distribution of variants between traits based on extremes and the general population and little etiological heterogeneity between obesity subgroups.

Loci influencing blood pressure identified using a cardiovascular gene-centric array

Blood pressure (BP) is a heritable determinant of risk for cardiovascular disease (CVD). To investigate genetic associations with systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP) and pulse pressure (PP), we genotyped ∼50 000 single-nucleotide polymorphisms (SNPs) that capture variation in ∼2100 candidate genes for cardiovascular phenotypes in 61 619 individuals of European ancestry from cohort studies in the USA and Europe. We identified novel associations between rs347591 and SBP (chromosome 3p25.3, in an intron of HRH1) and between rs2169137 and DBP (chromosome1q32.1 in an intron of MDM4) and between rs2014408 and SBP (chromosome 11p15 in an intron of SOX6), previously reported to be associated with MAP. We also confirmed 10 previously known loci associated with SBP, DBP, MAP or PP (ADRB1, ATP2B1, SH2B3/ATXN2, CSK, CYP17A1, FURIN, HFE, LSP1, MTHFR, SOX6) at array-wide significance (P < 2.4 × 10(-6)). We then replicated these associations in an independent set of 65 886 individuals of European ancestry. The findings from expression QTL (eQTL) analysis showed associations of SNPs in the MDM4 region with MDM4 expression. We did not find any evidence of association of the two novel SNPs in MDM4 and HRH1 with sequelae of high BP including coronary artery disease (CAD), left ventricular hypertrophy (LVH) or stroke. In summary, we identified two novel loci associated with BP and confirmed multiple previously reported associations. Our findings extend our understanding of genes involved in BP regulation, some of which may eventually provide new targets for therapeutic intervention.

C-peptide levels are associated with mortality and cardiovascular mortality in patients undergoing angiography: the LURIC study

OBJECTIVE

C-peptide is a proinsulin cleavage product released from the pancreas in amounts equimolar to insulin, and elevated levels of C-peptide have been found in patients with insulin resistance and early type 2 diabetes mellitus. Recent data suggest that C-peptide could play a causal role in the pathophysiology of vascular disease, but nothing is known about the prognostic value of C-peptide concentrations in the circulation.

RESEARCH DESIGN AND METHODS

We examined whether C-peptide is associated with cardiovascular and total mortality in 2,306 patients from the Ludwigshafen Risk and Cardiovascular Health Study who underwent coronary angiography at baseline (1997-2000).

RESULTS

During a mean follow-up of 7.6 years, 440 deaths (19.1%) occurred, 252 (10.9%) of which were due to cardiovascular causes. Age- and sex-adjusted hazard ratios (HRs) in the third compared with the first tertile of C-peptide were 1.46 (95% CI 1.15-1.85; P = 0.002) for all cause and 1.58 (1.15-2.18; P = 0.005) for cardiovascular mortality. After further adjustment for common risk factors as well as markers of glucose metabolism, these HRs remained significant at 1.46 (1.10-1.93; P = 0.008) and 1.55 (1.07-2.24; P = 0.022), respectively. Moreover, patients in higher tertiles of C-peptide exhibited higher levels of markers of endothelial dysfunction and atherosclerosis as well as a more severe extent of coronary lesions.

CONCLUSIONS

In patients undergoing coronary angiography, C-peptide levels are independently associated with all cause and cardiovascular mortality as well as presence and severity of coronary artery disease. Further studies are needed to examine a potential causal role of C-peptide in atherogenesis in humans.

Vitamin D and mortality: a Mendelian randomization study

BACKGROUND

Decreased circulating 25-hydroxy-vitamin D (25-OH-vitamin D) concentrations have been associated with mortality rates, but it is unclear whether this association is causal. We performed a Mendelian randomization study and analyzed whether 3 common single-nucleotide polymorphisms (SNPs) associated with 25-OH-vitamin D concentrations are causal for mortality rates.

METHODS

Genotypes of SNPs in the group-specific component gene (GC, rs2282679), 7-dehydrocholesterol reductase gene (DHCR7, rs12785878), and cytochrome P450 IIR-1 gene (CYP2R1, rs10741657) were determined in a prospective cohort study of 3316 male and female participants [mean age 62.6 (10.6) years] scheduled for coronary angiography between 1997 and 2000. 25-OH-vitamin D concentrations were determined by RIA. The main outcome measures were all-cause deaths, cardiovascular deaths, and noncardiovascular deaths.

RESULTS

In a linear regression model adjusting for month of blood sampling, age, and sex, vitamin D concentrations were predicted by GC genotype (P < 0.001), CYP2R1 genotype (P = 0.068), and DHCR7 genotype (P < 0.001), with a coefficient of determination (r(2)) of 0.175. During a median follow-up time of 9.9 years, 955 persons (30.0%) died, including 619 deaths from cardiovascular causes. In a multivariate Cox regression adjusted for classical risk factors, GC, CYP2R1, and DHCR7 genotypes were not associated with all-cause mortality, cardiovascular mortality, or noncardiovascular mortality.

CONCLUSIONS

Genetic variants associated with 25-OH-vitamin D concentrations do not predict mortality. This suggests that low 25-OH-vitamin D concentrations are associated with, but unlikely to be causal for, higher mortality rates.

Genome-wide association analyses identify 18 new loci associated with serum urate concentrations

Elevated serum urate concentrations can cause gout, a prevalent and painful inflammatory arthritis. By combining data from >140,000 individuals of European ancestry within the Global Urate Genetics Consortium (GUGC), we identified and replicated 28 genome-wide significant loci in association with serum urate concentrations (18 new regions in or near TRIM46, INHBB, SFMBT1, TMEM171, VEGFA, BAZ1B, PRKAG2, STC1, HNF4G, A1CF, ATXN2, UBE2Q2, IGF1R, NFAT5, MAF, HLF, ACVR1B-ACVRL1 and B3GNT4). Associations for many of the loci were of similar magnitude in individuals of non-European ancestry. We further characterized these loci for associations with gout, transcript expression and the fractional excretion of urate. Network analyses implicate the inhibins-activins signaling pathways and glucose metabolism in systemic urate control. New candidate genes for serum urate concentration highlight the importance of metabolic control of urate production and excretion, which may have implications for the treatment and prevention of gout.

Genome-wide association study pinpoints a new functional apolipoprotein B variant influencing oxidized low-density lipoprotein levels but not cardiovascular events: AtheroRemo Consortium

BACKGROUND

Oxidized low-density lipoprotein may be a key factor in the development of atherosclerosis. We performed a genome-wide association study on oxidized low-density lipoprotein and tested the impact of associated single-nucleotide polymorphisms (SNPs) on the risk factors of atherosclerosis and cardiovascular events.

METHODS AND RESULTS

A discovery genome-wide association study was performed on a population of young healthy white individuals (N=2080), and the SNPs associated with a P<5×10(-8) were replicated in 2 independent samples (A: N=2912; B: N=1326). Associations with cardiovascular endpoints were also assessed with 2 additional clinical cohorts (C: N=1118; and D: N=808). We found 328 SNPs associated with oxidized low-density lipoprotein. The genetic variant rs676210 (Pro2739Leu) in apolipoprotein B was the proxy SNP behind all associations (P=4.3×10(-136), effect size=13.2 U/L per allele). This association was replicated in the 2 independent samples (A and B, P=2.5×10(-47) and 1.1×10(-11), effect sizes=10.3 U/L and 7.8 U/L, respectively). In the meta-analyses of cohorts A, C, and D (excluding cohort B without angiographic data), the top SNP did not associate significantly with the age of onset of angiographically verified coronary artery disease (hazard ratio=1.00 [0.94-1.06] per allele), 3-vessel coronary artery disease (hazard ratio=1.03 [0.94-1.13]), or myocardial infarction (hazard ratio=1.04 [0.96-1.12]).

CONCLUSIONS

This novel genetic marker is an important factor regulating oxidized low-density lipoprotein levels but not a major genetic factor for the studied cardiovascular endpoints.

Genome-wide association study for circulating levels of PAI-1 provides novel insights into its regulation

We conducted a genome-wide association study to identify novel associations between genetic variants and circulating plasminogen activator inhibitor-1 (PAI-1) concentration, and examined functional implications of variants and genes that were discovered. A discovery meta-analysis was performed in 19 599 subjects, followed by replication analysis of genome-wide significant (P < 5 × 10(-8)) single nucleotide polymorphisms (SNPs) in 10 796 independent samples. We further examined associations with type 2 diabetes and coronary artery disease, assessed the functional significance of the SNPs for gene expression in human tissues, and conducted RNA-silencing experiments for one novel association. We confirmed the association of the 4G/5G proxy SNP rs2227631 in the promoter region of SERPINE1 (7q22.1) and discovered genome-wide significant associations at 3 additional loci: chromosome 7q22.1 close to SERPINE1 (rs6976053, discovery P = 3.4 × 10(-10)); chromosome 11p15.2 within ARNTL (rs6486122, discovery P = 3.0 × 10(-8)); and chromosome 3p25.2 within PPARG (rs11128603, discovery P = 2.9 × 10(-8)). Replication was achieved for the 7q22.1 and 11p15.2 loci. There was nominal association with type 2 diabetes and coronary artery disease at ARNTL (P < .05). Functional studies identified MUC3 as a candidate gene for the second association signal on 7q22.1. In summary, SNPs in SERPINE1 and ARNTL and an SNP associated with the expression of MUC3 were robustly associated with circulating levels of PAI-1.

Seventy-five genetic loci influencing the human red blood cell

Anaemia is a chief determinant of global ill health, contributing to cognitive impairment, growth retardation and impaired physical capacity. To understand further the genetic factors influencing red blood cells, we carried out a genome-wide association study of haemoglobin concentration and related parameters in up to 135,367 individuals. Here we identify 75 independent genetic loci associated with one or more red blood cell phenotypes at P < 10(-8), which together explain 4-9% of the phenotypic variance per trait. Using expression quantitative trait loci and bioinformatic strategies, we identify 121 candidate genes enriched in functions relevant to red blood cell biology. The candidate genes are expressed preferentially in red blood cell precursors, and 43 have haematopoietic phenotypes in Mus musculus or Drosophila melanogaster. Through open-chromatin and coding-variant analyses we identify potential causal genetic variants at 41 loci. Our findings provide extensive new insights into genetic mechanisms and biological pathways controlling red blood cell formation and function.

Duration of type 2 diabetes strongly predicts all-cause and cardiovascular mortality in people referred for coronary angiography

OBJECTIVE

Type 2 diabetes represents a major cardiovascular risk factor. However, few studies have addressed the impact of the disease duration on mortality. Thus, we aimed to investigate the predictive value of diabetes duration for all-cause and cardiovascular mortality in subjects undergoing coronary angiography.

METHODS

We studied 2455 participants of the LUdwigshafen RIsk and Cardiovascular health study (1768 males/687 females). They had a mean ± standard deviation (SD) age of 63.1 ± 9.0 years (range: 40.0-79.9) and a mean ± SD body mass index of 27.7 ± 4.0 kg/m(2). 704 subjects were newly diagnosed with type 2 diabetes according to the 2010 criteria of the American Diabetes Association and 446 subjects had a known history of type 2 diabetes. The mean ± SD duration of the follow-up for all-cause and cardiovascular mortality was 7.4 ± 2.3 years.

RESULTS

A total of 543 deaths occurred during the follow-up. Among these, 343 were accounted for by cardiovascular diseases. The duration of type 2 diabetes was strongly and positively correlated with all-cause and cardiovascular mortality (both P<0.001). The multivariate adjusted hazard ratios (95% confidence intervals) for cardiovascular mortality compared to subjects without diabetes were 1.76 (1.34-2.32), 2.86 (2.00-4.08), 2.96 (1.85-4.74), and 4.55 (3.24-6.39) for subjects with new onset type 2 diabetes and subjects with known type 2 diabetes (duration ≤ 5, >5 and ≤ 10, >10 years), respectively.

CONCLUSIONS

The data emphasise the need to consider the diabetes duration for the prediction of mortality in subjects at intermediate to high cardiovascular risk.

Relationship between plasma aldosterone concentration and soluble cellular adhesion molecules in patients referred to coronary angiography

OBJECTIVE

Evidence is emerging that aldosterone contributes to the development and progression of atherosclerosis and cardiovascular disease. Little is known, however, regarding an association between circulating aldosterone levels and soluble cellular adhesion molecules in humans.

METHODS

We investigated the relationship between plasma aldosterone concentration (PAC) and soluble cellular adhesion molecules in a large cohort of patients referred to coronary angiography. After exclusion of patients with ongoing mineralocorticoid receptor blocker use, oral contraceptive or hormone replacement therapy, 1,733 patients (mean age: 62.5±10.8 years; 26.4%% women; mean PAC: 101.5±93.5 pg/mL) remained eligible for analyses.

RESULTS

Pearson correlation analysis as well as age and gender adjusted partial correlation analysis revealed a positive association between PAC and soluble (s) E-, L- and P-selectin levels but not with sICAM-1 and sVCAM-1, respectively. In multivariate adjusted analyses of covariance (ANCOVA) sE- (p=0.026), sL- (p=0.049) and sP-selectin (p<0.001) levels increased steadily from the first (reference) to the third gender-specific tertile of PAC. No significant variation across PAC tertiles was found for sICAM-1 (p=0.767) and sVCAM1 (p=0.425) levels, respectively. Finally, multivariate regression analyses revealed circulating aldosterone as an important predictor for soluble selectin levels.

CONCLUSION

Our findings in a large cohort of patients indicate that upregulation of selectins might represent a novel mechanism of aldosterone mediated development and progression of atherosclerosis. In view of aldosterone as a novel cardiovascular risk factor independent of angiotensin II, our findings warrant further interventional studies which should evaluate anti-atherosclerotic effects of aldosterone blocking treatment strategies in humans.

Additional use of glycated hemoglobin for diagnosis of type 2 diabetes in people undergoing coronary angiography reveals a subgroup at increased cardiovascular risk

OBJECTIVE

To study the prognosis of people with newly diagnosed type 2 diabetes as per the American Diabetes Association (ADA) 2010 definition but without diabetes as per the ADA 2009 definition.

RESEARCH DESIGN AND METHODS

A total of 2,002 participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study without a history of diabetes were studied.

RESULTS

During the follow-up of a mean duration ± SD of 7.7 ± 2.0 years, 346 people died (202 cardiovascular deaths). Subjects with type 2 diabetes as per the ADA 2009 definition (n = 468) had significantly increased all-cause and cardiovascular mortality compared with people without diabetes as per the ADA 2010 definition (both P ≤ 0.003). Subjects with type 2 diabetes as per the ADA 2010 definition but without diabetes as per the ADA 2009 definition (n = 150) were at significantly increased risk to die of cardiovascular diseases (P = 0.029).

CONCLUSIONS

Use of the ADA 2010 diabetes definition may be instrumental in improving cardiovascular risk stratification in people undergoing coronary angiography.

Investigation of 95 variants identified in a genome-wide study for association with mortality after acute coronary syndrome

Background

Genome-wide association studies (GWAS) have identified new candidate genes for the occurrence of acute coronary syndrome (ACS), but possible effects of such genes on survival following ACS have yet to be investigated.

Methods

We examined 95 polymorphisms in 69 distinct gene regions identified in a GWAS for premature myocardial infarction for their association with post-ACS mortality among 811 whites recruited from university-affiliated hospitals in Kansas City, Missouri. We then sought replication of a positive genetic association in a large, racially diverse cohort of myocardial infarction patients (N = 2284) using Kaplan-Meier survival analyses and Cox regression to adjust for relevant covariates. Finally, we investigated the apparent association further in 6086 additional coronary artery disease patients.

Results

After Cox adjustment for other ACS risk factors, of 95 SNPs tested in 811 whites only the association with the rs6922269 in MTHFD1L was statistically significant, with a 2.6-fold mortality hazard (P = 0.007). The recessive A/A genotype was of borderline significance in an age- and race-adjusted analysis of the entire combined cohort (N = 3095; P = 0.052), but this finding was not confirmed in independent cohorts (N = 6086).

Conclusions

We found no support for the hypothesis that the GWAS-identified variants in this study substantially alter the probability of post-ACS survival. Large-scale, collaborative, genome-wide studies may be required in order to detect genetic variants that are robustly associated with survival in patients with coronary artery disease.

Association of TCF7L2 SNPs with age at onset of type 2 diabetes and proinsulin/insulin ratio but not with glucagon-like peptide 1

BACKGROUND

Variants in TCF7L2 have been associated with the age at onset of type 2 diabetes in Mexican Americans. However, there is a lack of data on this relationship in Caucasians. Furthermore, risk alleles in TCF7L2 have been suggested to account for decreased conversion of proinsulin to insulin and decreased expression of GLP-1. We investigated the effect of the allelic variants rs1225537 and rs7903146 in TCF7L2 on the age at onset of type 2 diabetes, the plasma concentrations of proinsulin and GLP-1, and the ratio of proinsulin to insulin in a German cohort.

METHODS

We studied 3185 participants of the LUdwigshafen RIsk and Cardiovascular health (LURIC) study. Among these, 1021 subjects had type 2 diabetes. Data on age at onset of diabetes were available in 925 subjects. OGTTs were performed in a subgroup not previously known to have diabetes.

RESULTS

Carriers of the risk alleles in rs1225537 and rs7901346 had increased risk of type 2 diabetes and elevated HbA(1c) (all p < 0.001). The risk alleles were also associated with early onset of type 2 diabetes, decreased insulin secretion and markedly increased proinsulin and proinsulin to insulin ratio (all p < 0.03). GLP-1 was not significantly related to the TCF7L2 genotype.

CONCLUSIONS

Our data demonstrate that TCF7L2 variants are associated with an early age of onset of type 2 diabetes in Caucasians and affects the conversion of proinsulin to insulin. However, TCF7L2 is not consistently associated with fasting GLP-1.

Lipopolysaccharide-binding protein (LBP) is associated with total and cardiovascular mortality in individuals with or without stable coronary artery disease--results from the Ludwigshafen Risk and Cardiovascular Health Study (LURIC)

BACKGROUND

Atherosclerosis of coronary arteries is hallmarked by non-specific local inflammatory processes accompanied by a systemic response. Lipopolysaccharide-binding protein (LBP) has been suggested to be associated with coronary artery disease (CAD) in a previous study without follow-up.

PATIENTS AND METHODS

LBP plasma levels were measured in 2959 participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) cohort study referred to coronary angiography at baseline between 1997 and 2000. Median follow-up time was 8.0 years. Primary and secondary end points were cardiovascular and all-cause mortality, respectively. Multivariable adjusted logistic regression analyses were conducted to investigate the role of LBP.

RESULTS

Serum LBP concentration was significantly increased in 2298 patients with angiographically confirmed CAD compared to 661 individuals without coronary atherosclerosis (6.78 μg/mL (5.46-8.84) vs. 6.13 μg/mL (5.05-7.74), respectively; p<0.001). Moreover in multivariable logistic regression analyses, adjusted for established cardiovascular risk factors and markers of systemic inflammation, LBP was a significant and independent predictor of total and cardiovascular mortality (hazard ratio (HR) for all cause mortality: 1.43, 95% CI: 1.06-1.94, p=0.024; HR for cardiovascular mortality in the 4th quartile of LBP: 1.55, 95% CI: 1.06-2.27, p=0.025).

CONCLUSION

The present results add information on LBP in CAD. The data underscore the potential importance of innate immune mechanisms for atherosclerosis. Further studies are needed to clarify the pathways between innate immune system activation and atherosclerosis.

Glycated hemoglobin predicts all-cause, cardiovascular, and cancer mortality in people without a history of diabetes undergoing coronary angiography

OBJECTIVE

Glycated hemoglobin has been suggested to be superior to fasting glucose for the prediction of vascular disease and death from any cause. The aim of the present work was to analyze and compare the predictive value of glycated hemoglobin and fasting glucose on all-cause and cause-specific mortality in subjects who underwent coronary angiography.

RESEARCH DESIGN AND METHODS

We studied 2,686 participants of the Ludwigshafen Risk and Cardiovascular health study without a history of diabetes. The majority of this cohort had coronary artery disease. Glycated hemoglobin was measured at the baseline examination. The mean (± SD) duration of the follow-up for all-cause, cardiovascular, and cancer mortality was 7.54 ± 2.1 years.

RESULTS

A total of 508 deaths occurred during the follow-up. Of those, 299 were accounted for by cardiovascular diseases and 79 by cancer. Baseline glycated hemoglobin was predictive of all-cause, cardiovascular, and cancer mortality. The multivariable-adjusted hazard ratios (HR) (95% CI) for glycated hemoglobin values of <5.0, 5.0-5.4, 5.5-5.9, 6.0-6.4, 6.5-7.4, and ≥7.5% for all-cause mortality were 1.36 (0.85-2.18), 1.00 (0.76-1.32), 1.00 (reference), 1.11 (0.88-1.41), 1.39 (1.07-1.82), and 2.15 (1.32-3.53), respectively. Similar J-shaped relationships were found between glycated hemoglobin and cardiovascular and cancer mortality. The associations of glycated hemoglobin with all-cause and cardiovascular mortality remained significant after inclusion of fasting glucose as a covariate. However, fasting glucose was not significantly related to mortality when adjusting for glycated hemoglobin.

CONCLUSIONS

Glycated hemoglobin significantly and independently of fasting glucose predicts all-cause and cardiovascular mortality in whites at intermediate to high cardiovascular risk.

Arginine bioavailability ratios are associated with cardiovascular mortality in patients referred to coronary angiography

OBJECTIVES

Arginine is the only source for nitric oxide (NO) synthesis. The bioavailability of NO plays a pivotal role in endothelial function and consequently in cardiovascular disease. The aim of the current study is to investigate the association of arginine bioavailability ratios with markers of endothelial function and cardiovascular mortality in patients referred to coronary angiography.

METHODS

We investigated 2236 patients recruited within the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study that were followed up for a median of 7.7 years. Arginine, ornithine and citrulline were chromatographically determined after precolumn-derivatisation followed by postcolumn continuous reaction with ninhydrin. Global arginine bioavailability (GABR) was calculated by arginine divided by the sum of ornithine plus citrulline.

RESULTS

We observed a significant rise in cardiovascular mortality with decreasing GABR and arginine to ornithine ratio quartiles. The adjusted Cox proportional HRs for GABR were 1.27 (0.88-1.83), 1.27 (0.89-1.80) and 1.75 (1.24-2.45) for the 3rd, the 2nd and the 1st quartile respectively in comparison to the 4th quartile. The HRs for the quartiles of the arginine to ornithine ratio were 1.83 (1.25-2.67), 2.17 (1.50-3.20) and 2.02 (1.39-2.92) respectively. Patients with type 2 diabetes mellitus had a significantly lower GABR than persons without diabetes (0.88 ± 0.23 vs. 0.94 ± 0.24, p<0.001). GABR was found to be inversely correlated with endothelial markers as VCAM-1 (r=-0.301, p<0.001) or ICAM-1 (r=-0.136, p<0.001).

CONCLUSIONS

GABR and the arginine to ornithine ratio are associated with markers of endothelial dysfunction and increased risk of cardiovascular mortality. Further studies are warranted to elucidate the pathobiology and clinical relevance of the arginine bioavailability ratios in cardio-metabolic diseases.

Apolipoprotein E genotypes, circulating C-reactive protein and angiographic coronary artery disease: the Ludwigshafen Risk and Cardiovascular Health Study

C-reactive protein (CRP) has been implicated in the development of atherosclerosis. The genetic polymorphism of apolipoprotein (apo) E is associated with the concentration of CRP. We analyzed the association between the apo E genotype, CRP and angiographic coronary artery disease (CAD). The concentration of CRP was similar in patients with stable CAD and in controls, but increased in patients presenting with acute coronary syndromes. In models adjusting for the main confounding variables, the alleles ɛ4 and ɛ2 were associated with decreased and increased concentrations of CRP, respectively, compared to the wild-type allele ɛ3. In spite of this, the ɛ2 allele was associated with a lower prevalence of angiographic CAD, while the slight over-representation of the ɛ4 allele was statistically not significant. We conclude that the apo E genotype is associated with circulating CRP. A causal role of CRP in the development of CAD would be supported if genotypes that raise CRP in the long-term were themselves associated with CAD. As we found the opposite, we suggest that the association between CRP and cardiovascular events reflects confounding and reverse causation.

Lipoprotein associated phospholipase A2 concentration predicts total and cardiovascular mortality independently of established risk factors (The Ludwigshafen Risk and Cardiovascular Health Study)

BACKGROUND

Lipoprotein-associated phospholipase A2 (LpPLA2) is a lipoprotein-bound enzyme involved in inflammation and atherosclerosis. This cohort study investigates LpPLA2 concentration to predict cardiovascular and total mortality in patients scheduled for coronary angiography.

METHODS

LpPLA2 concentration was determined in 2298 patients with and in 661 patients without angiographically confirmed coronary artery disease (CAD). During the median observation period of 8.0 years 686 patients died.

RESULTS

In patients with tertiles of LpPLA2 of 307 - 475 ng/mL, or > or = 475 ng/mL unadjusted hazard ratios (HR) for total mortality were 1.47 (95% CI 1.21 - 1.80; p < 0.001), and 1.63 (95% CI 135 - 1.97; p < 0.001), respectively, compared to patients with LpPLA2 < or = 307 ng/mL. HRs for cardiovascular death were 1.33 (95% CI 1.04 - 1.71; p = 0.026), and 1.59 (95% CI 1.26 - 2.02; p < 0.001), respectively. After accounting for established risk factors and including angiographic CAD status and high sensitivity C-reactive protein (hsCRP), the 3rd tertile of LpPLA2 concentration predicted death from all causes with a HR of 1.40 (95% CI 1.15 - 1.71; p = 0.001) and cardiovascular death with a HR of 1.35 (95% CI 1.05 - 1.73; p = 0.018). LpPLA2 increased the risk of cardiovascular death significantly even in individuals with high hsCRP. In patients with hsCRP > 33 mg/L and LpPLA2 > 392 ng/mL the risk of cardiovascular death was almost two-fold higher compared to patients with low hsCRP and low LpPLA2 with a HR of 1.98 (95% CI 1.50 - 2.62; p < 0.001).

CONCLUSIONS

LpPLA2 concentration predicts risk for total and cardiovascular mortality independently from established risk factors and indicates risk for cardiovascular death even in patients with high hsCRP levels.

Genome-wide association study identifies two novel regions at 11p15.5-p13 and 1p31 with major impact on acute-phase serum amyloid A

Elevated levels of acute-phase serum amyloid A (A-SAA) cause amyloidosis and are a risk factor for atherosclerosis and its clinical complications, type 2 diabetes, as well as various malignancies. To investigate the genetic basis of A-SAA levels, we conducted the first genome-wide association study on baseline A-SAA concentrations in three population-based studies (KORA, TwinsUK, Sorbs) and one prospective case cohort study (LURIC), including a total of 4,212 participants of European descent, and identified two novel genetic susceptibility regions at 11p15.5-p13 and 1p31. The region at 11p15.5-p13 (rs4150642; p = 3.20×10⁻¹¹¹) contains serum amyloid A1 (SAA1) and the adjacent general transcription factor 2 H1 (GTF2H1), Hermansky-Pudlak Syndrome 5 (HPS5), lactate dehydrogenase A (LDHA), and lactate dehydrogenase C (LDHC). This region explains 10.84% of the total variation of A-SAA levels in our data, which makes up 18.37% of the total estimated heritability. The second region encloses the leptin receptor (LEPR) gene at 1p31 (rs12753193; p = 1.22×10⁻¹¹) and has been found to be associated with CRP and fibrinogen in previous studies. Our findings demonstrate a key role of the 11p15.5-p13 region in the regulation of baseline A-SAA levels and provide confirmative evidence of the importance of the 1p31 region for inflammatory processes and the close interplay between A-SAA, leptin, and other acute-phase proteins.

An elevated level of acute-phase serum amyloid A (A-SAA), a sensitive marker of the acute inflammatory state with high heritability estimates, causes amyloidosis and is a risk factor for atherosclerosis and its clinical complications, type 2 diabetes, as well as various malignancies. This study describes the first genome-wide association study on baseline A-SAA concentrations. In a meta-analysis of four genome-wide scans totalling 4,212 participants of European descent, we identified two novel genetic susceptibility regions on chromosomes 11 and 1 to be associated with baseline A-SAA concentrations. The chromosome 11 region contains the serum amyloid A1 gene and the adjacent genes and explains a high percentage of the total estimated heritability. The chromosome 1 region is a known genetic susceptibility region for inflammation. Taken together, we identified one region, which seems to be of key importance in the regulation of A-SAA levels and represents a novel potential target for the investigation of related clinical entities. In addition, our findings indicate a close interplay between A-SAA and other inflammatory proteins, as well as a larger role of a known genetic susceptibility region for inflammatory processes as it has been assumed in the past.

Symmetrical and asymmetrical dimethylarginine as predictors for mortality in patients referred for coronary angiography: the Ludwigshafen Risk and Cardiovascular Health study

BACKGROUND

Asymmetrical dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, has been linked to cardiovascular risk. The clinical role of its structural isomer symmetrical dimethylarginine (SDMA) remains largely unclear.

METHODS

We measured SDMA and ADMA in 3229 patients undergoing coronary angiography at baseline (1997-2000) and recorded total and cardiovascular mortality during a median follow-up time of 7.7 years. We investigated associations of SDMA with cardiovascular risk factors and mortality and compared its role as a cardiovascular risk factor with ADMA, which predicted mortality in previous analyses of our study.

RESULTS

In linear regression analyses including common cardiovascular risk factors as covariates, SDMA and ADMA were significantly associated with cystatin C, N-terminal pro-B-type natriuretic peptide, New York Heart Association classification, and homocysteine. The regression coefficients were higher for SDMA than for ADMA. In Cox proportional-hazards models adjusted for cardiovascular risk factors, the hazard ratios (HRs) (with 95% CI) in the second, third, and fourth SDMA quartile compared to the lowest quartile were 0.77 (0.60-0.99), 0.99 (0.78-1.25), and 1.51 (1.20-1.91) for total mortality and 0.92 (0.68-1.25), 0.93 (0.68-1.26), and 1.54 (1.14-2.01) for cardiovascular mortality. The same calculations for ADMA quartiles revealed HRs of 1.05 (0.83-1.32), 1.19 (0.95-1.50), and 1.61 (1.30-1.99) for total mortality and HR of 1.00 (0.74-1.34), 1.26 (0.95-1.68), and 1.54 (1.18-2.02) for cardiovascular mortality.

CONCLUSIONS

Serum concentrations of SDMA are independently associated with increased cardiovascular and all-cause mortality in patients undergoing coronary angiography. The pattern of risk linked to SDMA is different from that linked to ADMA, suggesting different pathophysiological roles of these 2 methylarginine metabolites.

Homoarginine, Cardiovascular Risk, and Mortality

Background— Homoarginine is an amino acid derivative that may increase nitric oxide availability and enhance endothelial function. The effect of the level of homoarginine on cardiovascular outcome and mortality is unknown.

Methods and Results— We assessed cardiovascular and all-cause mortality according to homoarginine levels in a cohort of 3305 subjects referred for coronary angiography from the LUdwigshafen RIsk and Cardiovascular Health (LURIC) Study. After investigating the relation of homoarginine with kidney function and markers of endothelial dysfunction, we explored its effects on adverse outcomes in a second high-risk cohort of 1244 patients with type 2 diabetes mellitus receiving maintenance hemodialysis (4D study [Die Deutsche Diabetes Dialyse Studie]). In the LURIC study, mean serum homoarginine levels were 2.6±1.1 μmol/L. During a median follow-up of 7.7 years, 766 patients died. After adjustments for age and sex, patients in the lowest quartile (<1.85 μmol/L) had a >4-fold higher rate of dying of cardiovascular disease (hazard ratio 4.1, 95% confidence interval 3.0 to 5.7) than patients in the highest quartile (>3.1 μmol/L). Lower homoarginine levels were associated with lower estimated glomerular filtration rate and higher levels of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. Hemodialysed patients had lower mean homoarginine levels of 1.2±0.5 μmol/L and experienced a 5-fold increased mortality rate compared with LURIC patients (608 deaths during a median follow-up of 4 years). Homoarginine consistently affected mortality, which was 2-fold higher in 4D study patients in the lowest quartile (<0.87 μmol/L) than in patients in the highest quartile (>1.4 μmol/L).

Conclusions— Homoarginine levels are independently associated with cardiovascular and all-cause mortality in patients referred for coronary angiography and in patients undergoing hemodialysis. Future studies are needed to elucidate the underlying pathomechanisms.

Genetic Determinants of Major Blood Lipids in Pakistanis Compared With Europeans

Background—

Evidence is sparse about the genetic determinants of major lipids in Pakistanis.

Methods and Results—

Variants (n=45 000) across 2000 genes were assessed in 3200 Pakistanis and compared with 2450 Germans using the same gene array and similar lipid assays. We also did a meta-analysis of selected lipid-related variants in Europeans. Pakistani genetic architecture was distinct from that of several ethnic groups represented in international reference samples. Forty-one variants at 14 loci were significantly associated with levels of HDL-C, triglyceride, or LDL-C. The most significant lipid-related variants identified among Pakistanis corresponded to genes previously shown to be relevant to Europeans, such as CETP associated with HDL-C levels (rs711752; P <10 −13 ), APOA5/ZNF259 (rs651821; P <10 −13 ) and GCKR (rs1260326; P <10 −13 ) with triglyceride levels; and CELSR2 variants with LDL-C levels (rs646776; P <10 −9 ). For Pakistanis, these 41 variants explained 6.2%, 7.1%, and 0.9% of the variation in HDL-C, triglyceride, and LDL-C, respectively. Compared with Europeans, the allele frequency of rs662799 in APOA5 among Pakistanis was higher and its impact on triglyceride concentration was greater ( P -value for difference <10 −4 ).

Conclusions—

Several lipid-related genetic variants are common to Pakistanis and Europeans, though they explain only a modest proportion of population variation in lipid concentration. Allelic frequencies and effect sizes of lipid-related variants can differ between Pakistanis and Europeans.

Pharmacogenomics--10 years of progress: a cardiovascular perspective

In 2000, the year the first issue of Pharmacogenomics was launched, completion of the human genome sequence was publicly applauded, although in reality it took a few more years to obtain the first full sequence data. Within 10 years, sequencing technology has advanced to an extent seemed unreachable at that time. Whilst, in 2000, it took many years to sequence just one human genome, today such sequencing can be done within 1-2 weeks. Human genetic variation has been catalogued in depth to at least 5% prevalence in Caucasians and efforts are underway to broaden this coverage to at least 1%. Haplotype maps have been constructed to extract the most informative SNPs for genetic studies. Genome-wide association studies based on 500,000 to 1 million such SNPs for mapping and gene detection efforts are the norm today. Genotype-guided therapy is emerging into mainstream medicine, setting the stage for a future of personalized medicine as compared to today's group-based medicine, where therapeutic efficacy is defined from mean effects in large-scale Phase III studies in humans.

Smoking and atherosclerotic cardiovascular disease: part III: functional biomarkers influenced by smoking

Smoking cigarettes induces rapidly occurring and reversible functional changes in the cardiovascular system, which precede morphologic changes. These functional changes are also related to atherosclerotic disease development and thus may qualify as prognostic parameters in chronic smokers. As opposed to smoking-induced morphologic changes functional alterations occur and revert within minutes, thus, allowing for the detection of smoking-induced effects on the cardiovascular system within minutes following exposure to mainstream smoke. Some alterations represent 'direct' changes (e.g., endothelial function), others reflect changes in a different organ system (e.g., the autonomous nervous system influencing heart rate variability), while some represent the sum of alterations in many organs and systems (e.g., exercise performance influenced by the autonomous nervous and by endothelial and cardiac function). Since a specific functional parameter usually changes with at least one or several others, caution should be exercised when trying to establish a direct cause relationship between the alteration of a single parameter and a clinical outcome.

Smoking and atherosclerotic cardiovascular disease: Part I: atherosclerotic disease process

The normal endothelium inhibits platelet and leukocyte adhesion to the vascular surface maintaining a balance of profibrinolytic and prothrombotic activity. Endothelial function is assessed largely as endothelium-dependent vasomotion, partly based on the assumption that impaired endothelium-dependent vasodilation reflects the alteration of important endothelial functions. Atherosclerotic risk factors, such as hypercholesterolemia, hypertension, diabetes and smoking, are associated with endothelial dysfunction. In the diseased endothelium, the balance between pro- and antithrombotic, pro- and anti-inflammatory, pro- and antiadhesive or pro- and antioxidant effects shifts towards a proinflammatory, prothrombotic, pro-oxidative and proadhesive phenotype of the endothelium. A common mechanism underlying endothelial dysfunction is related to the increased vascular production of reactive oxygen species. Recent studies suggest that inflammation per se, and C-reactive protein in particular, may contribute directly to endothelial dysfunction. The loss of endothelial integrity is a hallmark of atherosclerosis and the causal possible link between each individual risk factor, the development of atherosclerosis and the subsequent clinical events, such as myocardial infarction or stroke.

Smoking and atherosclerotic cardiovascular disease: part II: role of cigarette smoking in cardiovascular disease development

Potential mechanisms and biomarkers of atherosclerosis related to cigarette smoking - a modifiable risk factor for that disease - are discussed in this article. These include smoking-associated inflammatory markers, such as leukocytes, high-sensitivity C-reactive protein, serum amyloid A, ICAM-1 and IL-6. Other reviewed markers are indicative for smoking-related impairment of arterial endothelial function (transcapillary leakage of albumin, inhibition of endogenous nitric oxide synthase activity and reduced endothelium-dependent vasodilation) or point to oxidative stress caused by various chemicals (cholesterol oxidation, autoantibodies to oxidized low-density lipoprotein, plasma levels of malondialdehyde and F(2)-isoprostanes and reduced antioxidant capacity). Smoking enhances platelet aggregability, increases blood viscosity and shifts the pro- and antithrombotic balance towards increased coagulability (e.g., fibrinogen, von Willebrand factor, ICAM-1 and P-selectin). Insulin resistance is higher in smokers compared with nonsmokers, and hemoglobin A1c is dose-dependently elevated, as is homocysteine. Smoke exposure may influence the kinetics of markers with different response to transient or chronic changes in cigarette smoking behavior.

Smoking and atherosclerotic cardiovascular disease: Part IV: Genetic markers associated with smoking

Genes influence smoking behavior, affect the metabolism of nicotine and specific chemicals produced during combustion, and enhance (or diminish) pathomechanistic pathways associated with the atherogenic potential of smoking, including oxidative stress, its inflammatory burden or procoagulant potential. Genome-wide association studies have revolutionized the search for new functional genetic markers with ever increasing marker density and the precision in identifying new genetic loci without the need for prior knowledge of functional pathways. Nevertheless, the statistical challenge remains to identify the few true positives, the need for replication of findings and the tedious work of identifying functional genetic variants and their mode of action. Genetic variation within a gene or in areas of the genetic code that control the expression of such a gene is far from being understood. Major advances include the detection of large-scale copy-number variants in the human genome and the demonstration of the decisive role of ‘miRNA’ in controlling gene expression. The role of the genomic methylation pattern in controlling the transcription of the underlying genetic sequence and its role in interacting with environmental influences have yet to be explored in depth. Although candidate genes and their genetic variants have been associated with atherosclerosis and cigarette smoking, a major breakthrough has still to be made.

The associations of cholesterol metabolism and plasma plant sterols with all-cause and cardiovascular mortality

Moderately elevated levels of plasma plant sterols have been suspected to be causally involved in atherosclerosis. The aim of this study was to investigate whether plant sterols and other markers of sterol metabolism predicted all-cause and cardiovascular mortality in participants of the Ludwigshafen Risk and Cardiovascular health (LURIC) study. A total of 1,257 individuals who did not use statins and at baseline had a mean (+/- SD) age of 62.8 (+/- 11.0) years were included in the present analysis. Lathosterol, cholestanol, campesterol, and sitosterol were measured to estimate cholesterol synthesis and absorption. The mean (+/- SD) time of the follow-up for all-cause and cardiovascular mortality was 7.32 (+/- 2.3) years. All-cause (P = 0.001) and cardiovascular (P = 0.006) mortality were decreased in the highest versus the lowest lathosterol to cholesterol tertile. In contrast, subjects in the third cholestanol to cholesterol tertile had increased all-cause (P < 0.001) and cardiovascular mortality (P = 0.010) compared with individuals in the first tertile. The third campesterol to cholesterol tertile was associated with increased all-cause mortality (P = 0.025). Sitosterol to cholesterol tertiles were not significantly related to all-cause or cardiovascular mortality. The data suggest that high absorption and low synthesis of cholesterol predict increased all-cause and cardiovascular mortality in LURIC participants.

Cholesteryl ester transfer protein and mortality in patients undergoing coronary angiography: the Ludwigshafen Risk and Cardiovascular Health study

BACKGROUND

The role of cholesteryl ester transfer protein (CETP) in the development of atherosclerosis is still open to debate. In the Investigation of Lipid Level Management to Understand its Impact in Atherosclerotic Events (ILLUMINATE) trial, inhibition of CETP in patients with high cardiovascular risk was associated with increased high-density lipoprotein levels but increased risk of cardiovascular morbidity and mortality. In this report, we present a prospective observational study of patients referred to coronary angiography in which CETP was examined in relation to morbidity and mortality.

METHODS AND RESULTS

CETP concentration was determined in 3256 participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study who were referred to coronary angiography at baseline between 1997 and 2000. Median follow-up time was 7.75 years. Primary and secondary end points were cardiovascular and all-cause mortality, respectively. CETP levels were higher in women and lower in smokers, in diabetic patients, and in patients with unstable coronary artery disease, respectively. In addition, CETP levels were correlated negatively with high-sensitivity C-reactive protein and interleukin-6. After adjustment for age, sex, medication, coronary artery disease status, cardiovascular risk factors, and diabetes mellitus, the hazard ratio for death in the lowest CETP quartile was 1.33 (1.07 to 1.65; P=0.011) compared with patients in the highest CETP quartile. Corresponding hazard ratios for death in the second and third CETP quartiles were 1.17 (0.92 to 1.48; P=0.19) and 1.10 (0.86 to 1.39; P=0.46), respectively.

CONCLUSIONS

We interpret our data to suggest that low endogenous CETP plasma levels per se are associated with increased cardiovascular and all-cause mortality, challenging the rationale of pharmacological CETP inhibition.

Neopterin as a Predictor of Total and Cardiovascular Mortality in Individuals Undergoing Angiography in the Ludwigshafen Risk and Cardiovascular Health Study

Background: Neopterin is produced upon activation of the cell-mediated immune response, and may be a novel risk marker for adverse outcomes resulting from coronary artery disease.

Methods: We measured neopterin in 1801 study participants with and 511 without angiographic coronary artery disease. Rates of death were determined after a median follow-up of 8.0 years.

Results: Estimated glomerular filtration rate and N-terminal pro-B–type natriuretic peptide (NT-proBNP) were the strongest predictors of neopterin. Neopterin was positively related to age and inversely related to LDL cholesterol, HDL cholesterol, and triglycerides. Use of lipid-lowering drugs lowered neopterin. Sex, body mass index, diabetes mellitus, hypertension, smoking status, Friesinger coronary score, and clinical instability at presentation were not associated with neopterin. Unlike C-reactive protein, neopterin was not increased in unstable angina pectoris, non–ST–elevation myocardial infarction, or ST-elevation myocardial infarction. In the third and fourth quartiles of neopterin, unadjusted hazard ratios for death from any cause were 1.94 (95% CI 1.44–2.61) and 3.32 (95% CI 2.53–4.30) compared to individuals in the first quartile, whereas hazard ratios for death from cardiovascular causes were 2.14 (95% CI 1.44–3.18) and 3.84 (95% CI 2.67–5.52), respectively. Neopterin remained predictive of total and cardiovascular mortality after adjusting for sex, age, body mass index, type 2 diabetes, hypertension, smoking status, LDL cholesterol, HDL cholesterol, triglycerides, estimated glomerular filtration rate, NT-proBNP, and clinical status at presentation, but NT-proBNP substantially weakened this association.

Conclusions: Neopterin is an independent predictor of all-cause and cardiovascular mortality in individuals with or without stable coronary artery disease.

Genetic variants of the promoter of the heme oxygenase-1 gene and their influence on cardiovascular disease (the Ludwigshafen Risk and Cardiovascular Health study)

BACKGROUND

Heme oxygenase-1 is an inducible cytoprotective enzyme which handles oxidative stress by generating anti-oxidant bilirubin and vasodilating carbon monoxide. A (GT)n dinucleotide repeat and a -413A>T single nucleotide polymorphism have been reported in the promoter region of HMOX1 to both influence the occurrence of coronary artery disease and myocardial infarction. We sought to validate these observations in persons scheduled for coronary angiography.

METHODS

We included 3219 subjects in the current analysis, 2526 with CAD including a subgroup of CAD and MI (n = 1339) and 693 controls. Coronary status was determined by coronary angiography. Risk factors and biochemical parameters (bilirubin, iron, LDL-C, HDL-C, and triglycerides) were determined by standard procedures. The dinucleotide repeat was analysed by PCR and subsequent sizing by capillary electrophoresis, the -413A>T polymorphism by PCR and RFLP.

RESULTS

In the LURIC study the allele frequency for the -413A>T polymorphism is A = 0,589 and T = 0,411. The (GT)n repeats spread between 14 and 39 repeats with 22 (19.9%) and 29 (47.1%) as the two most common alleles. We found neither an association of the genotypes or allelic frequencies with any of the biochemical parameters nor with CAD or previous MI.

CONCLUSION

Although an association of these polymorphisms with the appearance of CAD and MI have been published before, our results strongly argue against a relevant role of the (GT)n repeat or the -413A>T SNP in the HMOX1 promoter in CAD or MI.

Genetic variants and haplotypes of lipoprotein associated phospholipase A2 and their influence on cardiovascular disease (The Ludwigshafen Risk and Cardiovascular Health Study)

BACKGROUND

There is increasing evidence that lipoprotein-associated phospholipase A2 (LpPLA2) is associated with cardiovascular disease. However, it is still unclear whether LpPLA2 is simply a marker or has a causal role as either a pro- or anti-atherogenic factor.

METHODS

We analyzed the association of five polymorphisms (-1357G>A, -403T>C, Arg92His, Ile198Thr, Ala379Val) and related haplotypes at the PLA2G7 locus with angiographic coronary artery disease (CAD), plasma LpPLA2 activity, and long-term survival in 3234 patients scheduled for coronary angiography.

RESULTS

The promoter variant -403C and His(92) were associated with a decrease and Val(379) with an increase in plasma LpPLA2 activity. Both coding variants revealed a clear gene-dose effect. Interestingly, the rare Thr(198) allele, which was not associated with any change in plasma LpPLA2 activity, was more frequent in subjects without CAD (P = 0.009), with an adjusted odds ratio for CAD of 0.69 (95% CI: 0.49-0.96; P = 0.029). None of the analyzed variants showed any robust association with all-cause or cardiovascular mortality.

CONCLUSION

Irrespective of the significant association between some variants with plasma LpPLA2 activity, it is still unclear whether these polymorphisms or haplotypes are associated with the risk and outcome of cardiovascular disease in Caucasians.

Lymphocytes of type 2 diabetic women carry a high load of stable chromosomal aberrations: a novel risk factor for disease-related early death

OBJECTIVE

Diabetes is associated with an increased risk of death in women. Oxidative stress due to chronic hyperglycemia leads to the generation of reactive oxygen species and loss of chromosomal integrity. To clarify whether diabetes is a premature aging syndrome, we determined telomere erosion dynamics and occurrence of structural chromosomal aberrations in women of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study.

RESEARCH DESIGN AND METHODS

Telomere lengths and karyotypes were examined in peripheral blood mononuclear cells. Regarding these parameters, surviving and deceased type 2 diabetic women of the LURIC study were compared with nondiabetic LURIC women with or without coronary heart disease and with healthy female control subjects.

RESULTS

Significantly enhanced telomere attrition was seen in all LURIC subjects compared with healthy control subjects. Although the average telomere-length loss is equivalent to well >10 years of healthy aging, telomere erosion was not associated with outcome within the LURIC cohort. However, strikingly high numbers of stable chromosomal aberrations were found in type 2 diabetic women but not in LURIC disease control subjects or in healthy individuals. Furthermore, within the younger age- groups, deceased type 2 diabetes patients had significantly more marker chromosomes than the surviving type 2 diabetic patients.

CONCLUSIONS

All women at high risk for cardiovascular death have accelerated telomere erosion, not caused by type 2 diabetes per se but likely linked to other risk factors, including dyslipidemia. By contrast, the occurrence of marker chromosomes is associated with type 2 diabetes and is a novel risk factor for type 2 diabetes-related early death.

The relationships of cholesterol metabolism and plasma plant sterols with the severity of coronary artery disease

Changes in the balance of cholesterol absorption and synthesis and moderately elevated plasma plant sterols have been suggested to be atherogenic. Measuring cholestanol, lathosterol, campesterol, and sitosterol, we investigated the relationships of cholesterol metabolism and plasma plant sterols with the severity of coronary artery disease (CAD) in 2,440 participants of the Ludwigshafen Risk and Cardiovascular health (LURIC) study. The coronary status was determined by angiography, and the severity of CAD was assessed by the Friesinger Score (FS). An increase in the ratio of cholestanol to cholesterol was associated with high FS (P = 0.006). In contrast, a high ratio of lathosterol to cholesterol went in parallel with low FS (P < 0.001). Whereas the campesterol to cholesterol ratio significantly correlated with the FS (P = 0.026), the relationship of the sitosterol to cholesterol ratio with the FS did not reach statistical significance in the whole group. Increased campesterol, sitosterol, and cholestanol to lathosterol ratios were associated high FS (P < 0.001). To conclude, there is a modest association of high cholesterol absorption and low cholesterol synthesis with an increased severity of CAD. An atherogenic role of plasma plant sterols themselves, however, seems unlikely in subjects without sitosterolaemia.

Coagulation factor XII (FXII) activity, activated FXII, distribution of FXII C46T gene polymorphism and coronary risk

BACKGROUND

Whether factor XII (FXII) activity, its 46C>T polymorphism and activated FXII (FXIIa) are associated with coronary heart disease (CHD) remains to be determined.

METHODS

FXII, FXIIa and the FXII 46C>T polymorphism were determined in a hospital-based cohort of 2615 patients undergoing coronary angiography.

RESULTS

Fifty-seven per cent of the participants were identified as wild-type (46CC), 38% as heterozygous (46CT) and 5% as homozygous (46TT) for FXII 46C>T. FXII and FXIIa levels were significantly lower in carriers of the T-allele: 132 (97-151) U dL(-1) FXII in 46CC, 87 (77-99) U dL(-1) FXII in 46CT and 53 (42-67) U dL(-1) FXII in 46TT carriers (P < 0.001), and 2.8 (2.3-3.5) microg L(-1) FXIIa in CC, 2.1 (1.6-2.6) microg L(-1) FXIIa in CT and 1.2 (0.9-1.5) microg L(-1) FXIIa in TT carriers (P < 0.001; medians, lower and upper quartiles). Patients with stable CHD (n = 935), a history of myocardial infarction (n = 785) or who were suffering from acute coronary syndromes (ACS; n = 323) had significantly lower FXII levels than controls (n = 572). The differences remained statistically significant after adjustments for age, sex, diabetes mellitus, smoking, hypercholesterolemia and hypertension. Significantly reduced FXIIa levels in ACS patients lost significance once adjusted for covariates. FXII genotype was not associated with any clinical phenotype.

CONCLUSION

Lower FXII activity represents an independent risk for CHD and ACS. This is not the case for FXIIa levels or the FXII 46C>T variation.

Results of a non-specific immunomodulation therapy in chronic heart failure (ACCLAIM trial): a placebo-controlled randomised trial

BACKGROUND

Evidence suggests that inflammatory mediators contribute to development and progression of chronic heart failure. We therefore tested the hypothesis that immunomodulation might counteract this pathophysiological mechanism in patients.

METHODS

We did a double-blind, placebo-controlled study of a device-based non-specific immunomodulation therapy (IMT) in patients with New York Heart Association (NYHA) functional class II-IV chronic heart failure, left ventricular (LV) systolic dysfunction, and hospitalisation for heart failure or intravenous drug therapy in an outpatient setting within the past 12 months. Patients were randomly assigned to receive IMT (n=1213) or placebo (n=1213) by intragluteal injection on days 1, 2, 14, and every 28 days thereafter. Primary endpoint was the composite of time to death from any cause or first hospitalisation for cardiovascular reasons. The study continued until 828 primary endpoint events had accrued and all study patients had been treated for at least 22 weeks. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00111969.

FINDINGS

During a mean follow-up of 10.2 months, there were 399 primary events in the IMT group and 429 in the placebo group (hazard ratio 0.92; 95% CI 0.80-1.05; p=0.22). In two prespecified subgroups of patients--those with no history of previous myocardial infarction (n=919) and those with NYHA II heart failure (n=689)--IMT was associated with a 26% (0.74; 0.57-0.95; p=0.02) and a 39% (0.61; 95% CI 0.46-0.80; p=0.0003) reduction in the risk of primary endpoint events, respectively.

INTERPRETATION

Non-specific immunomodulation may have a role as a potential treatment for a large segment of the heart failure population, which includes patients without a history of myocardial infarction (irrespective of their functional NYHA class) and patients within NYHA class II.

Coagulation factor XII (FXII) activity, activated FXII, distribution of FXII C46T gene polymorphism and coronary risk

BACKGROUND

Whether factor XII (FXII) activity, its 46C>T polymorphism and activated FXII (FXIIa) are associated with coronary heart disease (CHD) remains to be determined.

METHODS

FXII, FXIIa and the FXII 46C>T polymorphism were determined in a hospital-based cohort of 2615 patients undergoing coronary angiography.

RESULTS

Fifty-seven per cent of the participants were identified as wild-type (46CC), 38% as heterozygous (46CT) and 5% as homozygous (46TT) for FXII 46C>T. FXII and FXIIa levels were significantly lower in carriers of the T-allele: 132 (97-151) U dL(-1) FXII in 46CC, 87 (77-99) U dL(-1) FXII in 46CT and 53 (42-67) U dL(-1) FXII in 46TT carriers (P < 0.001), and 2.8 (2.3-3.5) microg L(-1) FXIIa in CC, 2.1 (1.6-2.6) microg L(-1) FXIIa in CT and 1.2 (0.9-1.5) microg L(-1) FXIIa in TT carriers (P < 0.001; medians, lower and upper quartiles). Patients with stable CHD (n = 935), a history of myocardial infarction (n = 785) or who were suffering from acute coronary syndromes (ACS; n = 323) had significantly lower FXII levels than controls (n = 572). The differences remained statistically significant after adjustments for age, sex, diabetes mellitus, smoking, hypercholesterolemia and hypertension. Significantly reduced FXIIa levels in ACS patients lost significance once adjusted for covariates. FXII genotype was not associated with any clinical phenotype.

CONCLUSION

Lower FXII activity represents an independent risk for CHD and ACS. This is not the case for FXIIa levels or the FXII 46C>T variation.