Lowering of Circulating Sclerostin May Increase Risk of Atherosclerosis and Its Risk Factors: Evidence From a Genome-Wide Association Meta-Analysis Followed by Mendelian Randomization

OBJECTIVE

In this study, we aimed to establish the causal effects of lowering sclerostin, target of the antiosteoporosis drug romosozumab, on atherosclerosis and its risk factors.

METHODS

A genome-wide association study meta-analysis was performed of circulating sclerostin levels in 33,961 European individuals. Mendelian randomization (MR) was used to predict the causal effects of sclerostin lowering on 15 atherosclerosis-related diseases and risk factors.

RESULTS

We found that 18 conditionally independent variants were associated with circulating sclerostin. Of these, 1 cis signal in SOST and 3 trans signals in B4GALNT3, RIN3, and SERPINA1 regions showed directionally opposite signals for sclerostin levels and estimated bone mineral density. Variants with these 4 regions were selected as genetic instruments. MR using 5 correlated cis-SNPs suggested that lower sclerostin increased the risk of type 2 diabetes mellitus (DM) (odds ratio [OR] 1.32 [95% confidence interval (95% CI) 1.03-1.69]) and myocardial infarction (MI) (OR 1.35 [95% CI 1.01-1.79]); sclerostin lowering was also suggested to increase the extent of coronary artery calcification (CAC) (β = 0.24 [95% CI 0.02-0.45]). MR using both cis and trans instruments suggested that lower sclerostin increased hypertension risk (OR 1.09 [95% CI 1.04-1.15]), but otherwise had attenuated effects.

CONCLUSION

This study provides genetic evidence to suggest that lower levels of sclerostin may increase the risk of hypertension, type 2 DM, MI, and the extent of CAC. Taken together, these findings underscore the requirement for strategies to mitigate potential adverse effects of romosozumab treatment on atherosclerosis and its related risk factors.

Markers of bone metabolism are associated in all-cause mortality in heart failure with reduced ejection fraction

Background

In patients with heart failure an increased risk of fracture-related mortality has been reported. A growing body of evidence suggests that, heart failure (HF) itself may be related to disturbances in bone metabolism, but the exact mechanism remains unclear. In patients with HF previous studies indicated a loss of renal function and alterations in bone micro-architecture, but the clinical relevance remains unclear.

Purpose

We aimed to evaluate the association between markers of bone metabolism with mortality and pro-brain natriuretic peptide (proBNP) in patients with HF with reduced ejection fraction (HFrEF).

Methods

We analysed participants of a prospective cohort study of patients referred to coronary angiography (CA). The baseline examination was performed at a tertiary care centre in Germany. Indications for CA were based on clinical routine. For the current analysis only patients with HFrEF were included. Patients were selected based on echocardiographic left ventricular (LV)-EF≤40%, symptoms of heart failure and elevated proBNP concentrations, as recommended by current clinical guidelines.

We estimated the risk associated with parathyroid hormone (PTH), osteocalcin (OC), beta-crosslaps (βCL) and alkaline phosphatase (AP) and all-cause mortality using Cox proportional hazard models. Adjustments for demographic and clinical characteristics from the index hospital presentation were used as covariates. We included all individuals who had complete data for all variables in the study in our primary analysis. Additionally, we used linear regression analysis to investigate the correlation between proBNP and its association with PTH, OC, βCL and AP.

Results

A total of 297 participants (63.9±9.9 years; 17.9% females) were included in the analysis. Median follow-up was 10 years. Median LV-EF was 35%, median New York Heart Association functional class was 2 (IQR=1–3), mean pulmonary capillary wedge pressure was 15.3±7.4 mmHg and median proBNP levels of 2282 (IQR 1875–3758) ng/ml. Participants had in 42.3% multi-vessel atherosclerotic CAD (with stenosis of ≥50% considered diagnostic) with 66.4% had a previous myocardial infarction. In multivariate cox proportionate hazard models OC, βCL and AP were statistically significant associated with an increased risk for all-cause mortality (hazard ratio (HR)=1.6 [95% CI 1.2–2.2], HR=1.8 [95% CI 1.1–2.9] and HR=2.1 [95% CI 1.5–2.9], respectively).

In multivariate analysis proBNP was associated with PTH (β-coefficient = 0.076; P≤0.001), AP (β-coefficient = 0.125; P=0.001) and βCL (β-coefficient = 0.062; P=0.046), but not with osteocalcin (β-coefficient = −0.055; P=0.145).

Conclusion

In patients with HFrEF markers of bone metabolism were significantly associated with mortality and proBNP concentrations. Future studies should focus on different aspects of bone metabolism, fracture rates and fracture related mortality in patients with different stages of heart failure.

Funding Acknowledgement

Type of funding sources: None.

Ceramide-based lipid profiles and the prevalence of type 2 diabetes differ between patients with coronary artery disease and those with peripheral artery disease

Introduction

Serum lipids and metabolic diseases, in particular type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD), predict the atherosclerotic diseases coronary artery disease (CAD) and peripheral arterial disease (PAD).

Purpose

The purpose of this study was to investigate in how far a more detailed characterization including serum lipids improves discrimination of PAD from CAD.

Method

A cohort of 274 statin-naïve patients with either PAD (n=89) or stable CAD (n=185) were referred to metabolic screening and were characterized using nuclear magnetic resonance- and liquid chromatography-tandem mass spectrometry based advanced lipid and lipoprotein analysis. Results were validated in an independent cohort of 1239 patients with PAD or CAD.

Results

We found a significant difference in T2D prevalence and in the ceramide-based lipid profile between PAD and CAD patients. However, neither cholesterol-based markers (including LDL-C, HDL-C) and detailed lipoprotein profiles nor the LD status differed significantly between PAD and CAD patients (figure). The difference between ceramide-based lipid profiles of CAD and PAD remained significant also after adjusting for body composition, smoking, inflammatory parameters, and T2D.

Conclusion

We conclude that PAD and CAD differ in ceramide-based lipid profiles and T2D status, but not in other lipid characteristics or metabolic diseases.

Funding Acknowledgement

Type of funding sources: None.

MO048: Genome-wide studies reveal factors associated with circulating uromodulin and its relations with complex diseases

BACKGROUND AND AIMS

UMOD is a major risk gene for monogenic and complex forms of kidney disease. The encoded kidney-specific protein uromodulin is the most abundant protein in urine and related to chronic kidney disease, hypertension and pathogen defense. Through basolateral release from kidney epithelial cells, uromodulin also reaches the blood, where its function is largely unknown. To gain insights into potential systemic roles, we performed genome-wide screens of circulating uromodulin in seven cohorts using two complementary assays.

METHOD

Separate genome-wide association study meta-analyses for circulating uromodulin were conducted for the antibody-based assay (five cohorts, N = 13 985) and the aptamer-based SOMAscan assay (two cohorts, N = 18 070). Genome-wide significant loci were placed into their functional genomic context using RNA-seq, ATAC-seq and Hi-C data generated from primary human kidney tissue. An array of downstream genetic analyses was then performed for significant loci, including fine-mapping, colocalization analyses and gene-by-gene interaction analyses. The B4GALNT2 p.Cys466Arg allele was expressed in MDCK cells and studied by immunofluorescence and Western blotting analyses.

RESULTS

We detected and replicated 13 genome-wide significant loci (P <5e−8; 12 novel). At the UMOD locus, functional genomics data of primary human kidney tissue highlighted an upstream regulatory variant with differential accessibility and UMOD transcription in uromodulin-synthesizing kidney cells. Shared association patterns with complex traits, including chronic kidney disease and blood pressure, placed the PRKAG2 locus in the same context as UMOD. Experimental validation of another locus, B4GALNT2, showed that the detected p.Cys466Arg variant of the encoded N-acetylgalactosaminyltransferase has a loss-of-function effect leading to higher serum uromodulin levels. Lastly, our results point to enzymes writing glycan marks present on uromodulin and to their receptors in the circulation.

CONCLUSION

This study provides human genetic evidence of new pathway members of uromodulin and delivers novel insights into its determinants and systemic role in the circulation.

Red blood cell fatty acid patterns from 7 countries: Focus on the Omega-3 index

Red blood cell (RBC) fatty acid (FA) patterns are becoming recognized as long-term biomarkers of tissue FA composition, but different analytical methods have complicated inter-study and international comparisons. Here we report RBC FA data, with a focus on the Omega-3 Index (EPA + DHA in% of total FAs in RBC), from samples of seven countries (USA, Canada, Italy, Spain, Germany, South Korea, and Japan) including 167,347 individuals (93% of all samples were from the US). FA data were generated by a uniform methodology from a variety of interventional and observational studies and from clinical laboratories. The cohorts differed in size, demographics, health status, and year of collection. Only the Canadian cohort was a formal, representative population-based survey. The mean Omega-3 Index of each country was categorized as desirable (>8%), moderate (>6% to 8%), low (>4% to 6%), or very low (≤4%). Only cohorts from Alaska (treated separately from the US), South Korea and Japan showed a desirable Omega-3 Index. The Spanish cohort had a moderate Omega-3 Index, while cohorts from the US, Canada, Italy, and Germany were all classified as low. This study is limited by the use of cohorts of convenience and small sample sizes in some countries. Countries undertaking national health status studies should utilize a uniform method to measure Omega-3 FA levels.

Circulating Sclerostin Levels Are Positively Related to Coronary Artery Disease Severity and Related Risk Factors

Romosozumab is a newly available treatment for osteoporosis acting by sclerostin inhibition. Its cardiovascular safety has been questioned after finding excess cardiovascular disease (CVD)-related events in a pivotal phase 3 trial. Previous studies of relationships between circulating sclerostin levels and CVD and associated risk factors have yielded conflicting findings, likely reflecting small numbers and selected patient groups. We aimed to characterize relationships between sclerostin and CVD and related risk factors in more detail by examining these in two large cohorts, Ludwigshafen Risk and Cardiovascular Health study (LURIC; 34% female, mean age 63.0 years) and Avon Longitudinal Study of Parents and Children study (ALSPAC) mothers (mean age 48.1 years). Together these provided 5069 participants with complete data. Relationships between sclerostin and CVD risk factors were meta-analyzed, adjusted for age, sex (LURIC), body mass index, smoking, social deprivation, and ethnicity (ALSPAC). Higher sclerostin levels were associated with higher risk of diabetes mellitus (DM) (odds ratio [OR] = 1.25; 95% confidence interval [CI] 1.12, 1.37), risk of elevated fasting glucose (OR 1.15; CI 1.04, 1.26), and triglyceride levels (β 0.03; CI 0.00, 0.06). Conversely, higher sclerostin was associated with lower estimated glomerular filtration rate (eGFR) (β -0.20; CI -0.38, -0.02), HDL cholesterol (β -0.05; CI -0.10, -0.01), and apolipoprotein A-I (β -0.05; CI -0.08, -0.02) (difference in mean SD per SD increase in sclerostin, with 95% CI). In LURIC, higher sclerostin was associated with an increased risk of death from cardiac disease during follow-up (hazard ratio [HR] = 1.13; 1.03, 1.23) and with severity of coronary artery disease on angiogram as reflected by Friesinger score (0.05; 0.01, 0.09). Associations with cardiac mortality and coronary artery severity were partially attenuated after adjustment for risk factors potentially related to sclerostin, namely LDL and HDL cholesterol, log triglycerides, DM, hypertension, eGFR, and apolipoprotein A-I. Contrary to trial evidence suggesting sclerostin inhibition leads to an increased risk of CVD, sclerostin levels appear to be positively associated with coronary artery disease severity and mortality, partly explained by a relationship between higher sclerostin levels and major CVD risk factors. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Association of female sexual hormones with QTc time in hypertensive subjects

Background/Introduction

The rate corrected QT time (QTc) is the most commonly used ECG derived parameter to identify and risk-stratify inherited and acquired arrhythmia risk. Among the many potentially influencing factors, the female menstrual cycle has been described to lead to minor intra-individual changes, but the overall influence of sexual hormones on the QTc is incompletely understood. We therefore aimed to elucidate this relationship in hypertensive subjects.

Purpose

To identify confounding factors in QTc determination and elucidate potential endocrine causes of variable QTc time.

Methods

The Styrian Hypertension study is a cohort study aiming to identify novel cardiovascular risk factors. Subjects were recruited from a tertiary care center outpatient clinic. QTc was calculated according to Framingham and linear regression formulas adhering to the AHA/ACCF/HRS 2009 guideline for surface ECG interpretation. Plasma concentrations of estrone (E1), estradiol (E2), 17α-Hydroxyprogesterone and progesterone were measured by Biocrates AbsoluteIDQ Stero17 Kit. Patients on QTc altering medication were excluded from the present analyses.

Results

A total of 142 participants (mean [SD] age, 59.4 [11.7] years; 52% women, 80,1% post-menopause) were eligible for the present analyses. Linear regression analyses adjusted for potassium, HbA1c, NTproBNP and mean systolic blood pressure revealed only an association of QTc with progesterone (beta coefficient [95% CI]) of 0.38 [0.14 – 0.62] (P=0.002) in males. Detailed analyses revealed an U-shaped association. The other hormones showed no significant association in the present cohort of patients. Subgroups of premenopausal women and of patients without elevated blood pressure revealed no statistically significant results.

Conclusions

Contrary to previous evidence we found no sign. association between female sexual hormones and QTc time. We observed increased QTc time in males depending on their progesterone plasma concentrations, but the isolated finding may be a statistical outlier.

Funding Acknowledgement

Type of funding sources: None.

Digoxin treatment and long-term mortality depending on left ventricular ejection fraction and atrial fibrillation: a propensity score matched analysis

Background/Introduction

Atrial fibrillation (AF) is a common heart rhythm disturbance, associated with an increased risk of stroke, hospital admissions and mortality, especially in patients with reduced ejection fraction. Among the oldest medications used for heart-rate control is digitalis, but largely due to observational studies showing an increased risk of death it has fallen out of favour. Recently newer clinical trials reported that the treatment with digitalis in permanent AF might be superior to beta blocker therapy in regard to functional status and symptom burden. Given this diverging results we attempt to analysis a large cohort of patients facilitating a propensity score matching algorithm.

Purpose

To assess the associations of digitalis treatment with mortality in patients with increased cardiovascular risk.

Methods

Patients were derived from a large cohort study including participants from a tertiary care centre who were referred to coronary angiography. The propensity score matching is based on a predefined list of variables, with digitalis as treatment. Matching strategy is nearest neighbour matching and to prove consistency, radius matching (radius = 0.1). For survival analysis we used a Cox proportional hazard regression comparing patients with and without digitalis for all-cause mortality. The analysis is conducted using STATA 13 MP. All patients provided written informed consent and the study was approved by the ethics committee.

Results

A total of 2457 patients (median age: 63.5 [IQR = 56.3–70.6] years, 30.1% women) referred to coronary angiography, with a median follow up of 9.9 (IQR = 8.5–10.7) years were included. The matching process and the resulting propensity score fulfilled all statistical assumptions and resulted in a balanced cohort. The risk for all-cause mortality was higher among propensity score matched participants not treated with digitalis compared to patients on treatment (n=514) HR 3.03 (95% CI 2.5 to 3.7). Total mortality in patients with AF on digitalis after a median follow-up of 9.9 years was 27.6%. At baseline, only 42.4% of patients with AF were on oral anticoagulation.

Conclusions

In the present cohort treatment with digitalis was associated with a lower risk of all-cause mortality after long-term follow-up. The patient population has a clinically significant 10-year mortality risk. The results may not apply to other cohorts but may help inform future clinical trials.

Funding Acknowledgement

Type of funding sources: None.

Circulating uromodulin inhibits vascular calcification by interfering with pro-inflammatory cytokine signalling

AIMS

Uromodulin is produced exclusively in the kidney and secreted into both urine and blood. Serum levels of uromodulin are correlated with kidney function and reduced in chronic kidney disease (CKD) patients, but physiological functions of serum uromodulin are still elusive. This study investigated the role of uromodulin in medial vascular calcification, a key factor associated with cardiovascular events and mortality in CKD patients.

METHODS AND RESULTS

Experiments were performed in primary human (HAoSMCs) and mouse (MOVAS) aortic smooth muscle cells, cholecalciferol overload and subtotal nephrectomy mouse models and serum from CKD patients. In three independent cohorts of CKD patients, serum uromodulin concentrations were inversely correlated with serum calcification propensity. Uromodulin supplementation reduced phosphate-induced osteo-/chondrogenic transdifferentiation and calcification of HAoSMCs. In human serum, pro-inflammatory cytokines tumour necrosis factor α (TNFα) and interleukin-1β (IL-1β) co-immunoprecipitated with uromodulin. Uromodulin inhibited TNFα and IL-1β-induced osteo-/chondrogenic signalling and activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated β cells (NF-kB) as well as phosphate-induced NF-kB-dependent transcriptional activity in HAoSMCs. In vivo, adeno-associated virus (AAV)-mediated overexpression of uromodulin ameliorated vascular calcification in mice with cholecalciferol overload. Conversely, cholecalciferol overload-induced vascular calcification was aggravated in uromodulin-deficient mice. In contrast, uromodulin overexpression failed to reduce vascular calcification during renal failure in mice. Carbamylated uromodulin was detected in serum of CKD patients and uromodulin carbamylation inhibited its anti-calcific properties in vitro.

CONCLUSIONS

Uromodulin counteracts vascular osteo-/chondrogenic transdifferentiation and calcification, at least in part, through interference with cytokine-dependent pro-calcific signalling. In CKD, reduction and carbamylation of uromodulin may contribute to vascular pathology.

Intronic Variants in OCT1 are Associated with All-Cause and Cardiovascular Mortality in Metformin Users with Type 2 Diabetes

PURPOSE

Organic cation transporters (Octs) use cations like endogenous compounds, toxins, and drugs, such as metformin, as substrates. Therefore, these proteins determine the pharmacokinetics and -dynamics of metformin and thus its efficacy. Of note, metformin is today the most commonly used pharmaceutical in the treatment of type 2 diabetes (T2DM) with nevertheless a great variability in clinical response, which attributes to genetic variances. The aim of this study was to determine the influence of intronic OCT1 SNPs on prevalence of all-cause and cardiovascular death.

PATIENTS AND METHODS

Genotypes of 27 intronic SNPs in OCT1 were investigated in the LURIC study, a prospective cohort of 3316 participants scheduled for coronary angiography. We investigated whether these variants were associated with all-cause and cardiovascular death in 73 individuals with T2DM under metformin therapy, in individuals without diabetes, individuals with T2DM and individuals with T2DM without metformin therapy.

RESULTS

In a multivariate Cox regression analysis adjusted for classical cardiovascular risk factors, 4 intronic OCT1 SNPs were significantly associated with all-cause and cardiovascular mortality in individuals with T2DM on metformin therapy.

CONCLUSION

According to their OCT1 genotype, some individuals with T2DM on metformin therapy might be prone to an increased risk of cardiovascular death.

P0076HOMOARGININE ASSOCIATES WITH RENAL AND CARDIAC FUNCTION IN FABRY DISEASE

Background and Aims

Patients with Fabry disease frequently develop progressive Fabry nephropathy, hypertrophic cardiomyopathy with arrhythmias and subsequent death, transient ischemic attacks and early cerebral stroke. Homoarginine is an amino acid derivative, mainly produced in the kidney from its precursor lysine. Homoarginine may increase nitric oxide availability, decrease the release of cytokines, modulate the renin-angiotensin-aldosterone system and improve cardiac contractility. We hypothesize that high homoarginine levels associate with less clinical symptoms and better renal function in patients with Fabry disease.

Method

This study investigated the homoarginin status and its association with renal function, left ventricular (LV) mass and adverse clinical symptoms in patients with Fabry disease. Homoarginine was measured by high-performance liquid chromatography in 162 patients who were genetically proven to have Fabry disease. GFR was determined by DTPA clearance. LV mass and cardiomyopathy were assessed by magnetic resonance imaging and echocardiography. In cross-sectional analyses, associations with adverse clinical outcomes were determined by linear and binary logistic regression analyses, respectively, and were adjusted for age, sex, and BMI.

Results

Patients had a mean age of 39±14 years and 41% were male. The mean homoarginine concentration was 2.0±1.0 µmol/l. Patients had a mean BMI of 23.7±4.5 kg/m2 and a mean GFR of 93±37 ml/min. Homoarginine was significantly correlated with GFR and proteinuria. The better the homoarginine status of the patients, the higher was their GFR (r=0.20, p=0.04) and the lower proteinuria (r=-0.21, p=0.03). Furthermore, LV mass was significantly higher with lower homoarginine levels (r=-0.30, p<0.01). Patients of the lowest homoarginine tertile had a 4-fold higher risk of myocardial hypertrophy (OR 4.17, 95% CI 1.44-12.02), especially with septal and posterior hypertrophy, compared to those of the upper tertiles. Similarly, patients of the lowest homoarginine tertile had a higher rate of angina pectoris (OR 4.2, 95% CI 1.3-13.3) and chronic pain (OR 4.1, 95% CI 1.7-10.1), compared to patients of the upper tertiles. At lower homoarginine status, the median levels of proteinuria increased, as well as the prevalence rates of heart failure and the need for analgesic therapy.

Conclusion

In conclusion, low homoarginine status was strongly associated with cardiomyopathy, renal function and adverse clinical symptoms in patients with Fabry disease. Whether homoarginine supplementation improves complications of Fabry disease, requires a randomized controlled trial.

SO003LIFE-LONG NLRP3 INFLAMMASOME-MEDIATED SYSTEMIC INFLAMMATION ASSOCIATES WITH CARDIOVASCULAR MORTALITY: A GENETIC ASSOCIATION STUDY OF >500,000 INDIVIDUALS

Background and Aims

Chronic kidney disease (CKD) represents one of the strongest cardiovascular risk factors. Recently, we have shown that activation of the NOD-like receptor protein-3 (NLRP3) inflammasome mediates progression of kidney injury and CKD-associated vascular disease (Zewinger et al. Nat Immunol 2013). Components of the NLRP3 inflammasome pathway such as interleukin-1β (IL-1β) can therapeutically be targeted. Associations of genetically determined life-long inflammasome-mediated systemic inflammation with CVD and mortality in humans are unknown.

Method

We explored the association of genetic NLRP3 variants with prevalent CVD and cardiovascular mortality in 3,061 patients enrolled in the LURIC study undergoing coronary angiography in a gene-centric approach. Functional relevance of the rs10754555 NLRP3 variant was studied in freshly isolated human monocytes. Findings were validated in 39,755 participants from eight independent studies (CV risk populations) as well as in 483,258 participants of the UKBiobank study (general population).

Results

Genetic analyses identified the highly prevalent (MAF 39.9%) intronic NLRP3 variant rs10754555 to affect NLRP3 gene expression. rs10754555 carriers showed significantly higher C-reactive protein and serum amyloid A plasma levels. Expression of NLRP3 mRNA and inflammasome-dependent effector responses of isolated human monocytes from rs10754555 carriers were significantly higher as compared to non-carriers. In homozygous rs10754555 carriers, the prevalence of coronary artery disease (CAD) was significantly higher as compared to non-carriers with a significant interaction between rs10754555 and age in LURIC and in UKBiobank. Importantly, in LURIC and in UKBiobank, homozygous rs10754555 carriers had significantly higher risk for cardiovascular mortality during follow-up (HR 1.37, 95%-CI 1.08-1.74 and HR 1.13, 95%-CI 1.02-1.25, respectively). Consistently, rs10754555 was associated with higher cardiovascular mortality (HR 1.11, 95%-CI 1.05-1.16; P<0.001) in an additive model in patients with prevalent CAD.

Conclusion

The NLRP3 intronic variant rs10754555 is associated with increased systemic inflammation, inflammasome activation, prevalent CAD and mortality. This study provides evidence for a substantial role of life-long, genetically-driven systemic inflammation in cardiovascular disease and highlights the NLRP3 inflammasome as a therapeutic target in the general population and particular in patients with CKD.

Phenome-wide association studies on cardiovascular health and fatty acids considering phenotype quality control practices for epidemiological data

Phenome-wide association studies (PheWAS) allow agnostic investigation of common genetic variants in relation to a variety of phenotypes but preserving the power of PheWAS requires careful phenotypic quality control (QC) procedures. While QC of genetic data is well-defined, no established QC practices exist for multi-phenotypic data. Manually imposing sample size restrictions, identifying variable types/distributions, and locating problems such as missing data or outliers is arduous in large, multivariate datasets. In this paper, we perform two PheWAS on epidemiological data and, utilizing the novel software CLARITE (CLeaning to Analysis: Reproducibility-based Interface for Traits and Exposures), showcase a transparent and replicable phenome QC pipeline which we believe is a necessity for the field. Using data from the Ludwigshafen Risk and Cardiovascular (LURIC) Health Study we ran two PheWAS, one on cardiac-related diseases and the other on polyunsaturated fatty acids levels. These phenotypes underwent a stringent quality control screen and were regressed on a genome-wide sample of single nucleotide polymorphisms (SNPs). Seven SNPs were significant in association with dihomo-γ-linolenic acid, of which five were within fatty acid desaturases FADS1 and FADS2. PheWAS is a useful tool to elucidate the genetic architecture of complex disease phenotypes within a single experimental framework. However, to reduce computational and multiple-comparisons burden, careful assessment of phenotype quality and removal of low-quality data is prudent. Herein we perform two PheWAS while applying a detailed phenotype QC process, for which we provide a replicable pipeline that is modifiable for application to other large datasets with heterogenous phenotypes. As investigation of complex traits continues beyond traditional genome wide association studies (GWAS), such QC considerations and tools such as CLARITE are crucial to the in the analysis of non-genetic big data such as clinical measurements, lifestyle habits, and polygenic traits.

P5478Information on weather conditions improves the prognostic ability of 25 OH-vitamin D in stable coronary artery disease

Introduction and aim

Vitamin D deficiency is associated with an adverse prognosis in patients with coronary artery disease (CAD). Decreased levels of vitamin D are associated with low sunshine exposure, resulting in seasonal variations of vitamin D. The aims of this study were to investigate the influence of different specific weather conditions on vitamin D levels and to explore a possible improvement of risk stratification by vitamin D levels in stable patients with CAD using meteorological data.

Methods

The study population consists of two independent cohorts of stable patients undergoing coronary angiography with suspected or known CAD: as derivation cohort, the ongoing biomarker registry BioPROSPECTIVE with n=1,766 enrolled patients between 2010 and 2013 (median age 70.1 yrs; 30.8% females); and as validation cohort, the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study with n=3,299 patients (median age 63.5 yrs; 30.3% females). In the derivation cohort 235 (13.3%) patients were known to be deceased by 08/2018. In the validation cohort 760 (23.0%) patients died within a median follow-up time of 7.75 years. 25-OH vitamin D levels were measured by commercial assays. Vitamin D deficiency was defined as 25-OH vitamin D levels ≤20 ng/mL. Daily averaged data on six weather conditions of the 180 days prior to enrolment were collected for each patient from the weather station located closest to the respective study centre. Using air pressure, precipitation height, sunshine duration, temperature, relative humidity, and vapour pressure a weather model was constructed that significantly correlated with vitamin D levels (r=0.37; p<0.001).

Results

In the derivation cohort, median vitamin D levels were lower in non-survivors (13.3 [9.65–19.65] ng/mL) than in survivors (15.70 [10.7–22.65] ng/mL; p<0.001). Vitamin D predicted all-cause mortality with an area under the receiver operator characteristic curve (AUROC) of 0.576 (CI: 0.54–0.62). Adding the weather model to vitamin D significantly improved the AUROC to 0.601 (CI: 0.56–0.64; p=0.031). The vitamin D/weather model combination enhanced the prognostic value of the ESC SCORE to predict mortality (AUROC=0.571 [CI: 0.53–0.61] vs. 0.628 [CI: 0.59–0.67]; p=0.004). Comparable results were observed in the validation cohort. Here, vitamin D deficiency predicted mortality with a hazard ratio (HR) of 1.89 (CI: 1.59–2.26) after adjustment for ESC SCORE. Adding the weather model improved this HR to 1.92 (1.62–2.32). Reclassification analyses support the additive prognostic information of weather conditions with a continuous net reclassification improvement of 0.114 ([0.033–0.194]; p=0.006) if adding the weather model to vitamin D as base model for predicting mortality.

Conclusions

Different weather conditions show a significant impact on vitamin D levels in stable patients. Adding data on weather conditions improve the risk stratification by vitamin D for predicting mortality in stable CAD patients.

Acknowledgement/Funding

The study is financially supported by the Kerckhoff Heart Research Institute (KHFI) and the German Center for Cardiovascular Research (DZHK).

Mendelian Randomization Analysis Reveals a Causal Influence of Circulating Sclerostin Levels on Bone Mineral Density and Fractures

In bone, sclerostin is mainly osteocyte-derived and plays an important local role in adaptive responses to mechanical loading. Whether circulating levels of sclerostin also play a functional role is currently unclear, which we aimed to examine by two-sample Mendelian randomization (MR). A genetic instrument for circulating sclerostin, derived from a genomewide association study (GWAS) meta-analysis of serum sclerostin in 10,584 European-descent individuals, was examined in relation to femoral neck bone mineral density (BMD; n = 32,744) in GEFOS and estimated bone mineral density (eBMD) by heel ultrasound (n = 426,824) and fracture risk (n = 426,795) in UK Biobank. Our GWAS identified two novel serum sclerostin loci, B4GALNT3 (standard deviation [SD]) change in sclerostin per A allele (β = 0.20, p = 4.6 × 10^-49 ) and GALNT1 (β  = 0.11 per G allele, p = 4.4 × 10^-11 ). B4GALNT3 is an N-acetyl-galactosaminyltransferase, adding a terminal LacdiNAc disaccharide to target glycocoproteins, found to be predominantly expressed in kidney, whereas GALNT1 is an enzyme causing mucin-type O-linked glycosylation. Using these two single-nucleotide polymorphisms (SNPs) as genetic instruments, MR revealed an inverse causal relationship between serum sclerostin and femoral neck BMD (β = -0.12, 95% confidence interval [CI] -0.20 to -0.05) and eBMD (β = -0.12, 95% CI -0.14 to -0.10), and a positive relationship with fracture risk (β = 0.11, 95% CI 0.01 to 0.21). Colocalization analysis demonstrated common genetic signals within the B4GALNT3 locus for higher sclerostin, lower eBMD, and greater B4GALNT3 expression in arterial tissue (probability >99%). Our findings suggest that higher sclerostin levels are causally related to lower BMD and greater fracture risk. Hence, strategies for reducing circulating sclerostin, for example by targeting glycosylation enzymes as suggested by our GWAS results, may prove valuable in treating osteoporosis. © 2019 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc.

Adjusted Troponin I for Improved Evaluation of Patients with Chest Pain

The use of cardiac troponins (cTn) is the gold standard for diagnosing myocardial infarction. Independent of myocardial infarction (MI), however, sex, age and kidney function affect cTn levels. Here we developed a method to adjust cTnI levels for age, sex, and renal function, maintaining a unified cut-off value such as the 99th percentile. A total of 4587 individuals enrolled in a prospective longitudinal study were used to develop a model for adjustment of cTn. cTnI levels correlated with age and estimated glomerular filtration rate (eGFR) in males/females with rage = 0.436/0.518 and with reGFR = -0.142/-0.207. For adjustment, these variables served as covariates in a linear regression model with cTnI as dependent variable. This adjustment model was then applied to a real-world cohort of 1789 patients with suspected acute MI (AMI) (N = 407). Adjusting cTnI showed no relevant loss of diagnostic information, as evidenced by comparable areas under the receiver operator characteristic curves, to identify AMI in males and females for adjusted and unadjusted cTnI. In specific patients groups such as in elderly females, adjusting cTnI improved specificity for AMI compared with unadjusted cTnI. Specificity was also improved in patients with renal dysfunction by using the adjusted cTnI values. Thus, the adjustments improved the diagnostic ability of cTnI to identify AMI in elderly patients and in patients with renal dysfunction. Interpretation of cTnI values in complex emergency cases is facilitated by our method, which maintains a single diagnostic cut-off value in all patients.

Homoarginine-A prognostic indicator in adolescents and adults with complex congenital heart disease?

Background

Homoarginine (hArg) has been shown to be of prognostic value in patients with chronic left heart failure. The present study aims to assess the clinical utility and prognostic value of hArg levels in patients with complex congenital heart disease (CHD).

Methods

Plasma hArg levels were measured in 143 patients with complex CHD and compared to clinical status, echocardiographic and laboratory parameters as well as the occurrence of adverse cardiac events.

Results

Median hArg levels were 1.5 μmol/l in CHD patients as compared to 1.70 μmol/l in healthy controls (p = 0.051). Median hArg levels were lowest in patients with Fontan palliation (1.27 μmol/l) and Eisenmenger physiology (0.99 μmol/l) and decreased with the severity of adverse cardiac events with lowest values found in patients prior to death or overt heart failure (0.89 μmol/l). According to ROC analysis, the most important predictors of adverse cardiac events were hArg levels (AUC 0.837, p<0.001, CI 0.726–0.947), NYHA class (AUC 0.800, p<0.001, CI 0.672–0.928) and NT-proBNP levels (AUC 0.780, p<0.001, CI 0.669–0.891). The occurrence of overt heart failure or death due to progressive heart failure were best predicted by NYHA class (AUC 0.945, p<0.001, CI 0.898–0.992), hArg levels (AUC 0.911, p<0.001, CI 0.850–0.971) and NT-proBNP levels (AUC 0.877, p<0.001, CI 0.791–0.962), respectively.

Conclusion

In patients with complex CHD, hArg levels can predict adverse cardiac events as reliably as or even better than NT-proBNP levels and thus might be of prognostic value in this subset of patients.

Improved risk stratification in prevention by use of a panel of selected circulating microRNAs

Risk stratification is crucial in prevention. Circulating microRNAs have been proposed as biomarkers in cardiovascular disease. Here a miR panel consisting of miRs related to different cardiovascular pathophysiologies, was evaluated to predict outcome in the context of prevention. MiR-34a, miR-223, miR-378, miR-499 and miR-133 were determined from peripheral blood by qPCR and combined to a risk panel. As derivation cohort, 178 individuals of the DETECT study, and as validation cohort, 129 individuals of the SHIP study were used in a case-control approach. Overall mortality and cardiovascular events were outcome measures. The Framingham Risk Score(FRS) and the SCORE system were applied as risk classification systems. The identified miR panel was significantly associated with mortality given by a hazard ratio(HR) of 3.0 (95% (CI): 1.09–8.43; p = 0.034) and of 2.9 (95% CI: 1.32–6.33; p = 0.008) after adjusting for the FRS in the derivation cohort. In a validation cohort the miR-panel had a HR of 1.31 (95% CI: 1.03–1.66; p = 0.03) and of 1.29 (95% CI: 1.02–1.64; p = 0.03) in a FRS/SCORE adjusted-model. A FRS/SCORE risk model was significantly improved to predict mortality by the miR panel with continuous net reclassification index of 0.42/0.49 (p = 0.014/0.005). The present miR panel of 5 circulating miRs is able to improve risk stratification in prevention with respect to mortality beyond the FRS or SCORE.

Abstract P6-13-02: Efficacy of first-line bevacizumab (BEV)-containing therapy for poor-prognosis advanced breast cancer (aBC): Subgroup analyses of the German AVANTI observational study

Background: The multicenter AVANTI observational study is evaluating the safety and effectiveness of EU-approved BEV-containing regimens (BEV + paclitaxel [PAC] or BEV + capecitabine [CAP]) as first-line therapy for HER2-negative aBC in German routine oncology practice.

Methods: Eligible patients (pts) had received no prior chemotherapy (CT) for aBC and had no BEV contraindications. CT schedule, diagnostics, and frequency of follow-up visits are at the physician's discretion. Data are collected for 1 year after starting BEV, with 6-monthly follow-up for 1.5 years thereafter. We explored treatment outcomes in pts with triple-negative aBC (TNBC), pts considered at high risk according to a simple prognostic index for OS in BEV-treated pts [Llombart, 2014], and subgroups defined by timing of BEV+CT initiation.

Results: Between Oct 2009 and Feb 2015, 2168 pts treated at 331 centers received BEV+PAC (n=1774) or BEV+CAP (n=394). Of these, 445 (21%) had TNBC and 306 (14%) met the high-risk criteria. Within the hormone receptor-positive (HR+) subgroup, pts receiving endocrine therapy (ET) before BEV+CT were older than pts starting BEV+CT immediately (median age 65 vs 60 years, respectively) and included a smaller proportion with ECOG performance status 0 (39% vs 47%), visceral metastases (70% vs 77%), or prior (neo)adjuvant CT exposure (46% vs 57%). In all subgroups, median BEV treatment duration was longer than median CT duration. At the data cutoff for this interim analysis (Mar 1, 2015), median duration of observation was 10.8 (range &lt;0.1–47.5) months. The table shows treatment exposure and efficacy overall and in selected subgroups.

table 1 All pts (n=2168)TNBC (n=445)aHR+ with immediate BEV+CT (n=1260)a,bHR+ with ET before BEV+CT (n=309)a,bHigh riskc (n=306)bBEV+PAC, n (%)1774 (82)352 (79)b1062 (84)238 (77)229 (75)Treated until PD, n (%)b,d640 (30)180 (40)314 (25)104 (34)125 (41)BEV+CT until PD449 (21)143 (32)210 (17)61 (20)99 (32)Single-agent BEV until PD191 (9)37 (8)104 (8)43 (14)26 (8)Median BEV duration, months (95% CI)5.9 (5.6–6.3)5.1 (4.9–5.6)6.4 (5.9–7.0)5.6 (5.1–6.5)5.1 (4.6–5.6)Median CT duration, months4.6 (4.4–4.9)3.9 (3.5–4.2)4.9 (4.6–5.1)4.6 (4.2–5.1)3.9 (3.3–4.4)No. of PFS events/pts (%)e1238/2154 (57)302/441 (68)667/1255 (53)187/307 (61)210/306 (69)Median PFS, months (95% CI)10.1 (9.7–10.7)7.2 (6.2–8.0)11.5 (10.8–12.3)9.0 (8.3–10.0)6.4 (5.9–7.4)a154 pts could not be classified as TNBC or HR+ because of missing HR status information. bPost hoc analysis. c≥3 of the 5 risk factors (disease-free interval ≤24 months; ECOG performance status ≥2; liver metastases and/or ≥3 metastatic organ sites; TNBC; prior (neo)adjuvant anthracycline and/or taxane). dData available only in pts with documented end of treatment. ePFS data missing in 14 pts.

Conclusions: Interim results from this large observational study indicate that first-line BEV+CT is an effective therapy in all risk subgroups of a general population of pts with HER2-negative aBC treated in routine oncology practice, including pts with a particularly poor prognosis. Results of these exploratory subgroup analyses suggest that BEV+CT could be considered irrespective of HR status.

Citation Format: Mueller V, Jakob A, Aktas B, Pott D, Grafe A, Jungberg P, Maerz W, Fett W, Bruch H-R, Klare P, Boller E, Hoefflin S, Schneeweiss A. Efficacy of first-line bevacizumab (BEV)-containing therapy for poor-prognosis advanced breast cancer (aBC): Subgroup analyses of the German AVANTI observational study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-13-02.

The Proline 7 Substitution in the Preproneuropeptide Y Is Associated with Higher Hepatic Lipase Activity In Vivo

Hepatic lipase (HL) functions as a lipolytic enzyme that hydrolyzes triglycerides and phospholipids present in circulating plasma lipoproteins. Plasma HL activity is known to be regulated by hormonal and metabolic factors, but HL responsiveness to insulin as well as its role in modulating atherosclerotic risk is still controversial. We investigated on the influence of a known polymorphism in the neurotransmitter neuropeptide Y (NPY) on HL activity in two different cohorts consisting of diabetic and nondiabetic patients. HL activity was 24% and 34% higher on nondiabetic and diabetic subjects in the presence of the 7Pro allele in NPY, respectively. The presence of the 7Pro allele was an independent predictor of HL activity in multivariate analyses in both cohorts. These data suggest a regulatory effect of NPY on HL activity. Among carriers of the 7Pro allele, we also found a statistically significant lower absolute number of infarctions compared to noncarriers (p < 0.05) and a nonsignificant trend towards less myocardial infarction in the 7Pro allele diabetic carriers (p = 0.085). In conclusion, the common 7Pro allele in NPY was associated with higher HL activity in nondiabetic and diabetic subjects and its presence seems to coincide with a lower frequency of certain cardiovascular events.

Lipoprotein Apheresis for Lipoprotein(a)-Associated Cardiovascular Disease

Objective—

Lipoprotein(a)-hyperlipoproteinemia (Lp(a)-HLP) along with progressive cardiovascular disease has been approved as indication for regular lipoprotein apheresis (LA) in Germany since 2008. We aimed to study the long-term preventive effect of LA and to assess hypothetical clinical correlations of apolipoprotein(a) (apo(a)) by analyzing genotypes and phenotypes.

Approach and Results—

This prospective observational multicenter study included 170 patients with Lp(a)-HLP and progressive cardiovascular disease (48.9 years median age at diagnosis) despite other cardiovascular risk factors, including low-density lipoprotein cholesterol had maximally been treated (mean baseline low-density lipoprotein cholesterol: measured, 2.56 mmol/L [98.9 mg/dL] and corrected, 1.72 mmol/L [66.3 mg/dL]). Patients were prospectively investigated during a 5-year period about annual incidence rates of cardiovascular events. In addition, apo(a) isoforms and polymorphisms at the apo(a) gene ( LPA ) were characterized. One hundred fifty-four patients (90.6%) completed 5 years of follow-up. Mean Lp(a) concentration before commencing regular LA was 108.1 mg/dL. This was reduced by a single LA treatment by 68.1% on average. Significant decline of the mean annual cardiovascular event rate was observed from 0.58±0.53 2 years before regular LA to 0.11±0.15 thereafter ( P <0.0001); 95.3% of patients expressed at least 1 small apo(a) isoform. Small apo(a) isoform (35.2%) carrying phenotypes were not tagged by single-nucleotide polymorphisms rs10455872 or rs3798220.

Conclusions—

Results of 5 years of prospective follow-up confirm that LA has a lasting effect on prevention of cardiovascular events in patients with Lp(a)-HLP. Patients clinically selected by progressive cardiovascular disease were characterized by a highly frequent expression of small apo(a) isoforms. Only Lp(a) concentration seemed to comprehensively reflect Lp(a)-associated cardiovascular risk, however.

Correction: The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape: A Large-Scale Genome-Wide Interaction Study

[This corrects the article DOI: 10.1371/journal.pgen.1005378.].

The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape: A Large-Scale Genome-Wide Interaction Study

Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHR_adjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age- and/or sex-specific effects of genetic variants on BMI and WHR_adjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to ~2.8M SNPs with BMI and WHR_adjBMI in four strata (men ≤50y, men >50y, women ≤50y, women >50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR<5%) age-specific effects, of which 11 had larger effects in younger (<50y) than in older adults (≥50y). No sex-dependent effects were identified for BMI. For WHR_adjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHR_adjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHR_adjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.

Adult body size and body shape differ substantially between men and women and change over time. More than 100 genetic variants that influence body mass index (measure of body size) or waist-to-hip ratio (measure of body shape) have been identified. While there is evidence that some genetic loci affect body shape differently in men than in women, little is known about whether genetic effects differ in older compared to younger adults, and whether such changes differ between men and women. Therefore, we conducted a systematic genome-wide search, including 114 studies (>320,000 individuals), to specifically identify genetic loci with age- and or sex-dependent effects on body size and shape. We identified 15 loci of which the effect on BMI was different in older compared to younger adults, whereas we found no evidence for loci with different effects in men compared to women. The opposite was seen for body shape as we identified 44 loci of which the effect on waist-to-hip ratio differed between men and women, but no difference between younger and older adults were observed. Our observations may provide new insights into the biology that underlies weight change with age or the sexual dimorphism of body shape.

Increased Soluble ST2 Predicts Long-term Mortality in Patients with Stable Coronary Artery Disease: Results from the Ludwigshafen Risk and Cardiovascular Health Study

BACKGROUND

Soluble suppression of tumorigenicity 2 (sST2) has emerged as a strong prognostic biomarker in patients with heart failure and myocardial infarction. The aim of this study was to evaluate the long-term prognostic value of sST2 in patients with stable coronary artery disease (CAD).

METHODS

sST2 plasma concentrations were measured in 1345 patients with stable CAD referred for coronary angiography at a single tertiary care center. The primary endpoint was all-cause mortality.

RESULTS

During a median follow-up time of 9.8 years, 477 (36%) patients died. The median sST2 plasma concentration at baseline was significantly higher among decedents than survivors (21.4 vs 18.5 ng/mL; P &lt; 0.001). In multivariate Cox proportional hazards regression analysis, sST2 was an independent predictor of all-cause mortality (risk ratio 1.16 per 1-SD increase in log-transformed values; 95% CI 1.05–1.29; P = 0.004). In the same multivariate analysis, amino-terminal pro–B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) were also independent predictors, whereas galectin-3 was not. Patients with sST2 in the highest quartile (&gt;24.6 ng/mL) displayed a 2-fold increased risk of death in univariate analysis, which was attenuated but remained significant in a fully adjusted model (risk ratio 1.39; 95% CI 1.10–1.76; P = 0.006). Further analysis showed that the prognostic impact of sST2 was additive to NT-proBNP and hs-cTnT. Using a multibiomarker approach combining these 3 complementary makers, we demonstrated that patients with all 3 biomarkers in the highest quartiles had the poorest outcome.

CONCLUSIONS

In this cohort of patients with stable CAD, increased sST2 was an independent predictor of long-term all-cause mortality and provided complementary prognostic information to hs-cTnT and NT-proBNP.

Glycerophospholipid and sphingolipid species and mortality: the Ludwigshafen Risk and Cardiovascular Health (LURIC) study

Vascular and metabolic diseases cause half of total mortality in Europe. New prognostic markers would provide a valuable tool to improve outcome. First evidence supports the usefulness of plasma lipid species as easily accessible markers for certain diseases. Here we analyzed association of plasma lipid species with mortality in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. Plasma lipid species were quantified by electrospray ionization tandem mass spectrometry and Cox proportional hazards regression was applied to assess their association with total and cardiovascular mortality. Overall no differences were detected between total and cardiovascular mortality. Highly polyunsaturated phosphatidylcholine species together with lysophosphatidylcholine species and long chain saturated sphingomyelin and ceramide species seem to be associated with a protective effect. The predominantly circulating phosphatidylcholine-based as well as phosphatidylethanolamine-based ether species and phosphatidylethanolamine species were positively associated with total and cardiovascular mortality. Saturated and monounsaturated phosphatidylcholine species, especially phosphatidylcholine 32∶0 (most probably dipalmitoyl-phosphatidylcholine) and palmitate containing sphingomyelin and ceramide species showed together with 24∶1 containing sphingomyelin and ceramide species strongest positive association with mortality. A quotient of the sums of the six most protective species and the six species with the strongest positive mortality association indicated an almost 3-fold increased risk of mortality, which was higher than the hazard ratio for known risk factors in our cohort. Plasma lipid species levels and especially ratios of certain species may be valuable prognostic marker for cardiovascular and total mortality.

Association between a gene variant near ataxia telangiectasia mutated and coronary artery disease in men

OBJECTIVE

Type 2 diabetes is accompanied by increased mortality from coronary artery disease (CAD), but the mechanisms linking these conditions remain elusive. Hence, treatment of hyperglycaemia alone is not sufficient to avoid CAD in diabetes. Alternative views suggest that metabolic and vascular diseases share unifying cellular defects that could serve as targets for novel therapeutic strategies. Recently, a variant [single-nucleotide polymorphism (SNP); rs11212617] near the gene for ataxia telangiectasia mutated (ATM) has been associated with glycaemic response to metformin.

MATERIALS AND METHODS

We determined rs11212617 in 240 male patients who underwent elective coronary angiography.

RESULTS

While the variant was not associated with glucose concentrations, the A allele was significantly associated with the presence of CAD (chi-square, p = 0.003), as well as with logarithmically transformed quantitative CAD indices [severe score (SS): 0.5 (0.4-0.6) vs 0.3 (0.2-0.5); extent score (ES): 2.63 (2.4-2.9) vs 1.94 (1.4-2.4), both p < 0.05, respectively]. Multivariate analysis revealed an independent association between the A allele with ES (β = 0.17, p < 0.01).

CONCLUSION

Our data suggest that ATM-dependent signalling might play a role in the development of atherosclerotic vascular disease, but larger studies are necessary to substantiate such a hypothesis.

Lipoprotein Apheresis in Patients With Maximally Tolerated Lipid-Lowering Therapy, Lipoprotein(a)-Hyperlipoproteinemia, and Progressive Cardiovascular Disease

Background—

Lipoprotein(a) (Lp(a)) hyperlipoproteinemia is a major risk factor for cardiovascular disease, which is not affected by treatment of other cardiovascular risk factors. This study sought to assess the effect of chronic lipoprotein apheresis (LA) on the incidence of cardiovascular events in patients with progressive cardiovascular disease receiving maximally tolerated lipid-lowering treatment.

Methods and Results—

In a prospective observational multicenter study, 170 patients were investigated who commenced LA because of Lp(a)-hyperlipoproteinemia and progressive cardiovascular disease. Patients were characterized regarding plasma lipid status, lipid-lowering drug treatment, and variants at the LPA gene locus. The incidence rates of cardiovascular events 2 years before (y-2 and y-1) and prospectively 2 years during LA treatment (y+1, y+2) were compared. The mean age of patients was 51 years at the first cardiovascular event and 57 years at the first LA. Before LA, mean low-density lipoprotein cholesterol and Lp(a) were 2.56±1.04 mmol·L −1 (99.0±40.1 mg·dL −1 ) and Lp(a) 3.74±1.63 µmol·L −1 (104.9±45.7 mg·dL −1 ), respectively. Mean annual rates for major adverse coronary events declined from 0.41 for 2 years before LA to 0.09 for 2 years during LA ( P <0.0001). Event rates including all vascular beds declined from 0.61 to 0.16 ( P <0.0001). Analysis of single years revealed increasing major adverse coronary event rates from 0.30 to 0.54 ( P =0.001) for y-2 to y-1 before LA, decline to 0.14 from y-1 to y+1 ( P <0.0001) and to 0.05 from y+1 to y+2 ( P =0.014).

Conclusions—

In patients with Lp(a)-hyperlipoproteinemia, progressive cardiovascular disease, and maximally tolerated lipid-lowering medication, LA effectively lowered the incidence rate of cardiovascular events.

Clinical Trial Registration—

URL: https://drks-neu.uniklinik-freiburg.de . Unique identifier: DRKS00003119.

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.

Large-scale association analyses identify new loci influencing glycemic traits and provide insight into the underlying biological pathways

Through genome-wide association meta-analyses of up to 133,010 individuals of European ancestry without diabetes, including individuals newly genotyped using the Metabochip, we have increased the number of confirmed loci influencing glycemic traits to 53, of which 33 also increase type 2 diabetes risk (q < 0.05). Loci influencing fasting insulin concentration showed association with lipid levels and fat distribution, suggesting impact on insulin resistance. Gene-based analyses identified further biologically plausible loci, suggesting that additional loci beyond those reaching genome-wide significance are likely to represent real associations. This conclusion is supported by an excess of directionally consistent and nominally significant signals between discovery and follow-up studies. Functional analysis of these newly discovered loci will further improve our understanding of glycemic control.

Lipoprotein (a) and risk of cardiovascular disease--a systematic review and meta analysis of prospective studies

BACKGROUND

Several studies have investigated the role of Lipoprotein (a) as a risk factor for cardiovascular disease (CVD) and have produced controversial results.

DATA SOURCES

We conducted a systematic literature review in the databases MEDLINE, EMBASE, and COCHRANE aimed at retrieving prospective studies that investigated the prognostic value of Lipoprotein (a) concentrations on cardiovascular risk and mortality.

METHODS

From each study we extracted estimates of risk ratios (RR) with respect to the risk of CVD (endpoints: all coronary heart disease (CHD) events pooled, major coronary events, myocardial infarction, stroke) and all cause mortality. Study specific risk ratios were standardised to contrast the top third with the bottom third of the study specific Lipoprotein (a) distribution. Pooled summary estimates were calculated by using fixed and random effects meta analysis techniques, in total and stratified by study design and study population.

RESULTS

For the present meta analysis we selected 67 prospective studies including 181,683 individuals. Synthesising data from 37 studies that reported estimates for the endpoint 'CHD events' resulted in a RR of 1.57 (95% CI: 1.41 to 1.75, p < 0.001). For this endpoint subgroup analyses by design and population showed significant estimates: population based cohort studies: n = 15 studies, RR = 1.48 (95% CI: 1.26 to 1.74, p < 0.001), cohort studies including patients with previous disease: total: n = 11 studies, RR = 1.67 (95% CI: 1.28 to 2.17, p < 0.001), with CHD: n = 6 studies, RR = 2.37 (95% CI: 1.41 to 3.97, p = 0.001), nested case control studies: n = 11 studies, RR = 1.64 (95% CI: 1.47 to 1.83, p < 0.001). We did not find any significant effect on risk of stroke (n = 16 studies, RR = 1.10 (95% CI: 0.97 to 1.25, p = 0.137)) and mortality (n = 9 studies, RR = 1.12 (95% CI: 0.94 to 1.33, p = 0.200)).

CONCLUSIONS

This meta analysis of prospective studies shows a clear association between elevated Lipoprotein (a) levels and increased risk of CHD. This effect is substantially higher in individuals with previous CHD. Our systematic review showed no evidence of an effect on stroke and all cause mortality.

Improvement of fractional flow reserve and collateral flow by treatment with external counterpulsation (Art.Net.-2 Trial)

BACKGROUND

Arteriogenesis (collateral artery growth) is nature's most efficient rescue mechanism to overcome the fatal consequences of arterial occlusion or stenosis. The goal of this trial was to investigate the effect of external counterpulsation (ECP) on coronary collateral artery growth.

MATERIALS AND METHODS

A total of 23 patients (age 61 +/- 2.5 years) with stable coronary artery disease and at least one haemodynamic significant stenosis eligible for percutaneous coronary intervention were prospectively recruited into the two study groups in a 2 : 1 manner (ECP : control). One group (ECP group, n = 16) underwent 35 1-h sessions of ECP in 7 weeks. In the control group (n = 7), the natural course of collateral circulation over 7 weeks was evaluated. All patients underwent a cardiac catheterization at baseline and after 7 weeks, with invasive measurements of the pressure-derived collateral flow index (CFIp, primary endpoint) and fractional flow reserve (FFR).

RESULTS

In the ECP group, the CFIp (from 0.08 +/- 0.01 to 0.15 +/- 0.02; P < 0.001) and FFR (from 0.68 +/- 0.03 to 0.79 +/- 0.03; P = 0.001) improved significantly, while in the control group no change was observed. Only the ECP group showed a reduction of the Canadian Cardiovascular Society (CCS, P = 0.008) and New York Heart Association (NYHA, P < 0.001) classification.

CONCLUSION

In this study, we provide direct functional evidence for the stimulation of coronary arteriogenesis via ECP in patients with stable coronary artery disease. These data might open a novel noninvasive and preventive treatment avenue for patients with non-acute vascular stenotic disease.