A genetic association study of circulating coagulation factor VIII and von Willebrand factor levels.

ABSTRACT: Coagulation factor VIII (FVIII) and its carrier protein von Willebrand factor (VWF) are critical to coagulation and platelet aggregation. We leveraged whole-genome sequence data from the Trans-Omics for Precision Medicine (TOPMed) program along with TOPMed-based imputation of genotypes in additional samples to identify genetic associations with circulating FVIII and VWF levels in a single-variant meta-analysis, including up to 45 289 participants. Gene-based aggregate tests were implemented in TOPMed. We identified 3 candidate causal genes and tested their functional effect on FVIII release from human liver endothelial cells (HLECs) and VWF release from human umbilical vein endothelial cells. Mendelian randomization was also performed to provide evidence for causal associations of FVIII and VWF with thrombotic outcomes. We identified associations (P < 5 × 10-9) at 7 new loci for FVIII (ST3GAL4, CLEC4M, B3GNT2, ASGR1, F12, KNG1, and TREM1/NCR2) and 1 for VWF (B3GNT2). VWF, ABO, and STAB2 were associated with FVIII and VWF in gene-based analyses. Multiphenotype analysis of FVIII and VWF identified another 3 new loci, including PDIA3. Silencing of B3GNT2 and the previously reported CD36 gene decreased release of FVIII by HLECs, whereas silencing of B3GNT2, CD36, and PDIA3 decreased release of VWF by HVECs. Mendelian randomization supports causal association of higher FVIII and VWF with increased risk of thrombotic outcomes. Seven new loci were identified for FVIII and 1 for VWF, with evidence supporting causal associations of FVIII and VWF with thrombotic outcomes. B3GNT2, CD36, and PDIA3 modulate the release of FVIII and/or VWF in vitro.

Clinical characterization and mutation spectrum of patients with hypertriglyceridemia in a German outpatient clinic.

BACKGROUND: Severe hypertriglyceridemia (HTG) has predominantly multifactorial causes (MCS). Yet a small subset of patients have the monogenetic form (FCS). It remains a challenge to distinguish patients clinically, since decompensated MCS might mimic FCS´s severity. Aim of the current study was to determine clinical criteria that could sufficiently distinguish both forms as well as to apply the FCS score proposed by Moulin and colleagues. METHODS: We retrospectively studied 72 patients who presented with severe HTG in our clinic during a time span of seven years and received genetic testing. We classified genetic variants (ACMG-criteria), followed by genetic categorization into MCS or FCS. Clinical data were gathered from the medical records and the FCS score was calculated for each patient. RESULTS: Molecular genetic screening revealed eight FCS patients and 64 MCS patients. Altogether, we found 13 pathogenic variants of which four have not been described before. The FCS patients showed a significantly higher median triglyceride level compared to the MCS. The FCS score yielded a sensitivity of 75% and a specificity of 93.7% in our cohort, and significantly differentiated between the FCS and MCS group (p<0.001). CONCLUSIONS: In our cohort we identified several variables that significantly differentiated FCS from MCS. The FCS score performed similar to the original study by Moulin, thereby further validating the discriminatory power of the FCS score in an independent cohort.

Blood coagulation in Prediabetes clusters-impact on all-cause mortality in individuals undergoing coronary angiography.

BACKGROUND: Metabolic clusters can stratify subgroups of individuals at risk for type 2 diabetes mellitus and related complications. Since obesity and insulin resistance are closely linked to alterations in hemostasis, we investigated the association between plasmatic coagulation and metabolic clusters including the impact on survival. METHODS: Utilizing data from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study, we assigned 917 participants without diabetes to prediabetes clusters, using oGTT-derived glucose and insulin, high-density lipoprotein cholesterol, triglycerides, and anthropometric data. We performed a comprehensive analysis of plasmatic coagulation parameters and analyzed their associations with mortality using proportional hazards models. Mediation analysis was performed to assess the effect of coagulation factors on all-cause mortality in prediabetes clusters. RESULTS: Prediabetes clusters were assigned using published tools, and grouped into low-risk (clusters 1,2,4; n = 643) and high-risk (clusters 3,5,6; n = 274) clusters. Individuals in the high-risk clusters had a significantly increased risk of death (HR = 1.30; CI: 1.01 to 1.67) and showed significantly elevated levels of procoagulant factors (fibrinogen, FVII/VIII/IX), D-dimers, von-Willebrand factor, and PAI-1, compared to individuals in the low-risk clusters. In proportional hazards models adjusted for relevant confounders, elevated levels of fibrinogen, D-dimers, FVIII, and vWF were found to be associated with an increased risk of death. Multiple mediation analysis indicated that vWF significantly mediates the cluster-specific risk of death. CONCLUSIONS: High-risk prediabetes clusters are associated with prothrombotic changes in the coagulation system that likely contribute to the increased mortality in those individuals at cardiometabolic risk. The hypercoagulable state observed in the high-risk clusters indicates an increased risk for cardiovascular and thrombotic diseases that should be considered in future risk stratification and therapeutic strategies.

The role of functional vitamin D deficiency and low vitamin D reservoirs in relation to cardiovascular health and mortality.

OBJECTIVES: The role of vitamin D deficiency in cardiovascular disease (CVD) is controversial. Inherent biological and analytical limitations compromise the specificity of widely used 25-hydroxyvitamin D [25(OH)D] cut-offs. Simultaneous determination of 25(OH)D and 24,25-dihydroxyvitamin D [24,25(OH)2D] permits a functional assessment of vitamin D metabolism. The present study compared the associations of functional vitamin D deficiency and low vitamin D reservoirs with CVD mortality and CVD burden. METHODS: 25(OH)D, 24,25(OH)2D, the degree of coronary obstruction on angiography, high-sensitive cardiac troponin T (hs-cTnT), N-terminal brain natriuretic peptide (NT-proBNP), and 10-year CVD mortality were obtained from 2,456 participants of the LURIC (Ludwigshafen Risk and Cardiovascular Health) study. RESULTS: Neither low 25(OH)D concentrations nor functional vitamin D deficiency were associated with the number of atherosclerotic coronary arteries or the degree of coronary obstruction. Over a median follow-up of 9.9 years, 454 participants died (23.6 %) due to CVD. CVD mortality was doubled in individuals with 25(OH)D concentrations below the widely used cut-off for deficiency of <50 nmol/L [20 ng/mL] (21.6 vs. 11.5 %). In individuals with and without functional vitamin D deficiency, CVD mortality was 25.0 and 16.7 %, respectively. NT-proBNP and heart failure prevalence were also higher in vitamin D deficient individuals. CONCLUSIONS: Vitamin D deficient individuals have markedly higher CVD mortality, but only marginally higher hs-cTnT concentrations. A higher prevalence of heart failure and higher NT-proBNP concentrations suggest a link between vitamin D deficiency and cardiac function. The traditional and metabolic assessment of vitamin D status showed comparable associations for the different parameters of cardiac health.

IL-6 and hsCRP predict cardiovascular mortality in patients with heart failure with preserved ejection fraction.

AIMS: Inflammation accompanies heart failure (HF) and elevated levels of inflammatory biomarkers are linked to new onset of HF. However, whether the prognostic relevance of inflammatory biomarkers is different in HF with reduced (HFrEF) and preserved ejection fraction (HFpEF) is unclear. The aim of the current study is to explore the role of inflammation on the mortality risk in patients with HF. METHODS: We analysed interleukin-6 and hsCRP levels by ELISA and immunonephelometry, respectively, in HFpEF and HFrEF patients referred for coronary angiography and assessed the prognostic value in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. RESULTS: HF was present in 1086 patients (N = 506 HFpEF; N = 580 HFrEF; mean age 65 ± 10 years; 28% female). Increasing IL-6 levels were significantly associated with increased CV mortality in HFpEF [1.5 (95% CI: 1.1-2.2), P = 0.018] but not HFrEF [HR 1.3 (95% CI: 1.0-1.7), P = 0.06] patients. High-sensitive CRP followed a similar pattern but failed to reach statistical significance after full-adjustment (HFpEF: HR 1.4 95%C I: 1.0-2.0; P = 0.065; HFrEF HR: 1.0 95% CI: 0.7-1.3; P = 0.800). Interaction analysis in patients stratified by IL-6 and N terminal pro brain natriuretic peptide (NT-proBNP) above and below the median revealed a stepwise increase in CV-mortality in HFpEF (P = 0.036) but not HFrEF patients (P = 0.220). To investigate the relationship between IL-6 and NT-proBNP, we assessed the genetic IL6-Receptor variant p.Asp358Ala (rs2228145) which is linked to impaired IL-6 receptor signalling. Homozygous carriers with HFpEF but not HFrEF exhibited significantly lower NT-pro-BNP levels compared with wildtype carriers (HFpEF 779 pg/mL ± 787 vs. 1180 pg/ mL ± 1532; P = 0.008; HFrEF 2289 pg/ mL ± 3439 vs. 2326 pg/ mL ± 3386; P = 0.94), raising the hypothesis that IL-6 signalling may play a pathophysiological role in HFpEF. CONCLUSIONS: These data suggest a predictive value of elevated IL-6 for CV-mortality in HFpEF but not in HFrEF patients.

Clinical and genetic diagnosis of familial hypercholesterolaemia in patients undergoing coronary angiography: the Ludwigshafen Risk and Cardiovascular Health Study.

AIMS: To investigate the prevalence of familial hypercholesterolaemia (FH) and compare the performance of clinical criteria and genetic testing in patients undergoing coronary angiography. METHODS: The prevalence of FH was determined with the Dutch Lipid Clinical Network (DLCN), US-MEDPED, Simon Broome (SB) criteria, the 'Familial Hypercholesterolaemia Case Ascertainment Tool' (FAMCAT), and a clinical algorithm. Genetic screening was conducted with a custom array from Affymetrix (CARRENAL array) harboring 944 FH mutations. RESULTS: The study cohort consisted of 3267 patients (78.6% with coronary artery disease [CAD]). FH was diagnosed in 2.8%, 2.2%, 3.9%, and 7.9% using the DLCN, US-MEDPED, SB criteria, and the FAMCAT. The clinical algorithm identified the same patients as the SB criteria. Pathogenic FH mutations were found in 1.2% (1.2% in patients with CAD, 1.0% in patients without CAD). FH was more frequently diagnosed in younger patients. With genetic testing as reference, the clinical criteria achieved areas under the ROC curve (AUCs) in the range of 0.56-0.68. Using only LDL-C corrected for statin intake, an AUC of 0.68 was achieved. CONCLUSION: FH is up to fourfold more prevalent in patients undergoing coronary angiography than in contemporary cohorts representing the general population. Different clinical criteria yield substantially different diagnosis rates, overestimating the prevalence of FH compared to genetic testing. LDL-C testing alone may be sufficient to raise the suspicion of FH, which then needs to be corroborated by genetic testing.

Sex and statin-related genetic associations at the PCSK9 gene locus: results of genome-wide association meta-analysis.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key player of lipid metabolism with higher plasma levels in women throughout their life. Statin treatment affects PCSK9 levels also showing evidence of sex-differential effects. It remains unclear whether these differences can be explained by genetics. METHODS: We performed genome-wide association meta-analyses (GWAS) of PCSK9 levels stratified for sex and statin treatment in six independent studies of Europeans (8936 women/11,080 men respectively 14,825 statin-free/5191 statin-treated individuals). Loci associated in one of the strata were tested for statin- and sex-interactions considering all independent signals per locus. Independent variants at the PCSK9 gene locus were then used in a stratified Mendelian Randomization analysis (cis-MR) of PCSK9 effects on low-density lipoprotein cholesterol (LDL-C) levels to detect differences of causal effects between the subgroups. RESULTS: We identified 11 loci associated with PCSK9 in at least one stratified subgroup (p < 1.0 × 10-6), including the PCSK9 gene locus and five other lipid loci: APOB, TM6SF2, FADS1/FADS2, JMJD1C, and HP/HPR. The interaction analysis revealed eight loci with sex- and/or statin-interactions. At the PCSK9 gene locus, there were four independent signals, one with a significant sex-interaction showing stronger effects in men (rs693668). Regarding statin treatment, there were two significant interactions in PCSK9 missense mutations: rs11591147 had stronger effects in statin-free individuals, and rs11583680 had stronger effects in statin-treated individuals. Besides replicating known loci, we detected two novel genome-wide significant associations: one for statin-treated individuals at 6q11.1 (within KHDRBS2) and one for males at 12q24.22 (near KSR2/NOS1), both with significant interactions. In the MR of PCSK9 on LDL-C, we observed significant causal estimates within all subgroups, but significantly stronger causal effects in statin-free subjects compared to statin-treated individuals. CONCLUSIONS: We performed the first double-stratified GWAS of PCSK9 levels and identified multiple biologically plausible loci with genetic interaction effects. Our results indicate that the observed sexual dimorphism of PCSK9 and its statin-related interactions have a genetic basis. Significant differences in the causal relationship between PCSK9 and LDL-C suggest sex-specific dosages of PCSK9 inhibitors.

The protein "proprotein convertase subtilisin/kexin type 9" (PCSK9) regulates the levels of low-density lipoprotein cholesterol (LDL-C) in blood, and thus, contributes to the risk of cardio-vascular diseases. Women tend to have higher PCSK9 plasma levels throughout their life, although the difference is smaller in patients under LDL-C lowering medication (e.g., statins). We investigated the interplay of genetics, statin-treatment and sex, using combined data from six European studies. We detected 11 genetic regions associated with PCSK9 levels, of which one was specific for women (at SLCO1B3, a statin-transporter gene), and three were specific for men (e.g., ALOX5, encoding a protein linked to chronic inflammatory diseases such as atherosclerosis). We also tested if statin use changed the genetic effect and found five genes only associated with PCSK9 levels in untreated participants. Variants in the gene encoding PCSK9 were most strongly associated and had heterogeneous effects in dependence on statin treatment and sex: On one hand, there were genetic variants with stronger effects in men than women. Those variants are also linked to sex-differential gene expression of PCSK9. On the other hand, there were also variants with treatment-depending effects, linked to protein structure and functionality of PCSK9. This indicates that the observed sexual and treatment-related effects on PCSK9 levels have a genetic basis. In addition, we compared the causal effects of PCSK9 on LDL-C levels between men and women and found a different response to statin treatment. This highlights the need for sex-sensitive dosages of lipid-lowering medication.

Analysis of type 2 diabetes heterogeneity with a tree-like representation: insights from the prospective German Diabetes Study and the LURIC cohort.

BACKGROUND: Heterogeneity in type 2 diabetes can be represented by a tree-like graph structure by use of reversed graph-embedded dimensionality reduction. We aimed to examine whether this approach can be used to stratify key pathophysiological components and diabetes-related complications during longitudinal follow-up of individuals with recent-onset type 2 diabetes. METHODS: For this cohort analysis, 927 participants aged 18-69 years from the German Diabetes Study (GDS) with recent-onset type 2 diabetes were mapped onto a previously developed two-dimensional tree based on nine simple clinical and laboratory variables, residualised for age and sex. Insulin sensitivity was assessed by a hyperinsulinaemic-euglycaemic clamp, insulin secretion was assessed by intravenous glucose tolerance test, hepatic lipid content was assessed by 1 H magnetic resonance spectroscopy, serum interleukin (IL)-6 and IL-18 were assessed by ELISA, and peripheral and autonomic neuropathy were assessed by functional and clinical measures. Participants were followed up for up to 16 years. We also investigated heart failure and all-cause mortality in 794 individuals with type 2 diabetes undergoing invasive coronary diagnostics from the Ludwigshafen Risk and Cardiovascular Health (LURIC) cohort. FINDINGS: There were gradients of clamp-measured insulin sensitivity (both dimensions: p<0·0001) and insulin secretion (pdim1<0·0001, pdim2=0·00097) across the tree. Individuals in the region with the lowest insulin sensitivity had the highest hepatic lipid content (n=205, pdim1<0·0001, pdim2=0·037), pro-inflammatory biomarkers (IL-6: n=348, pdim1<0·0001, pdim2=0·013; IL-18: n=350, pdim1<0·0001, pdim2=0·38), and elevated cardiovascular risk (nevents=143, pdim1=0·14, pdim2<0·00081), whereas individuals positioned in the branch with the lowest insulin secretion were more prone to require insulin therapy (nevents=85, pdim1=0·032, pdim2=0·12) and had the highest risk of diabetic sensorimotor polyneuropathy (nevents=184, pdim1=0·012, pdim2=0·044) and cardiac autonomic neuropathy (nevents=118, pdim1=0·0094, pdim2=0·06). In the LURIC cohort, all-cause mortality was highest in the tree branch showing insulin resistance (nevents=488, pdim1=0·12, pdim2=0·0032). Significant gradients differentiated individuals having heart failure with preserved ejection fraction from those who had heart failure with reduced ejection fraction. INTERPRETATION: These data define the pathophysiological underpinnings of the tree structure, which has the potential to stratify diabetes-related complications on the basis of routinely available variables and thereby expand the toolbox of precision diabetes diagnosis. FUNDING: German Diabetes Center, German Federal Ministry of Health, Ministry of Culture and Science of the state of North Rhine-Westphalia, German Federal Ministry of Education and Research, German Diabetes Association, German Center for Diabetes Research, European Community, German Research Foundation, and Schmutzler Stiftung.

Subclases de Lipoproteínas de Alta Densidad, Enfermedad Coronaria y Mortalidad Cardiovascular / High Density Lipoprotein Subclasses, Coronary Artery Disease, and Cardiovascular Mortality

Antecedentes: La relación inversa entre el colesterol HDL y la mortalidad cardiovascular se debilita en presencia de enfermedad coronaria (EC). El objetivo de este trabajo fue investigar las asociaciones de las concentraciones de partículas de HDL con la mortalidad cardiovascular y el impacto de la EC en estas asociaciones. También se buscó evaluar comparativamente las concentraciones de colesterol HDL y partículas de HDL en la predicción de la mortalidad cardiovascular. Métodos: Las concentraciones totales de HDL y sus sub-clases se midieron mediante espectroscopía de resonancia magnética nuclear en 2.290 participantes del estudio LUdwigshafen RIsk and Cardiovascular Health remitidos para angiografía coronaria. Los participantes fueron seguidos prospectivamente durante una mediana (rango intercuartílico) con una duración de 10,0 (6,1-10,6) años. Resultados: La media de la edad (DE) de los participantes (1.575 hombres, 715 mujeres) fue de 62,9 (10,4) años, índice de masa corporal 27,6 (4,1) kg/m², colesterol-HDL 39 (11) mg/dL [1 (0,29) mmol/L], y la concentración total de partículas de HDL 24,1 (5,8) μmol/L. Cuatroscientos treinta y cuatro de los participantes murieron de enfermedad cardiovascular. En análisis multivariados, los tercilos de las concentraciones totales de partículas de HDL se relacionaron inversamente con la mortalidad cardiovascular (Hazard Ratio para 3° frente a 1° tercilo = 0,55; p<0,001). Esta asociación fue mediada principalmente por las partículas de HDL pequeñas (p<0,001). La adición a los modelos de predicción multivariada de las concentraciones de partículas HDL totales o pequeñas, en lugar de colesterol HDL, mejoró las métricas de rendimiento para predicción de mortalidad cardiovascular. La presencia de EC no tuvo impacto en las asociaciones entre las concentraciones de partículas de HDL y la mortalidad cardiovascular. Conclusiones: La alta concentración de partículas de HDL se encuentra asociada con una disminución de la mortalidad cardiovascular de manera consistente e independiente de la EC. Sin embargo, si esta relación inversa entre la concentración de partículas de HDL y la mortalidad cardiovascular se puede traducir en nuevas estrategias terapéuticas está aún bajo investigación.

Background: The inverse relationship between HDL cholesterol and cardiovascular mortality is weakened in coronary artery disease (CAD). We aimed to investigate the associations of HDL particle concentrations with cardiovascular mortality and the impact of CAD on these associations. We also sought to comparatively evaluate HDL cholesterol and HDL particle concentrations in predicting cardiovascular mortality. Methods: Total and subclass HDL particle concentrations were measured by nuclear magnetic resonance spectroscopy in 2,290 participants of the LUdwigshafen RIsk and Cardiovascular Health study referred for coronary angiography. The participants were prospectively followed over a median (interquartile range) duration of 10.0 (6.1-10.6) years. Results: The mean (SD) age of the participants (1,575 males, 715 females) was 62.9 (10.4) years, body mass index 27.6 (4.1) kg/m², HDL cholesterol 39 (11) mg/dL [1 (0.29) mmol/L], and total HDL particle concentration 24.1 (5.8) μmol/L. 434 persons died from cardiovascular diseases. In multivariate analyses, tertiles of total HDL particle concentrations were inversely related to cardiovascular mortality (HR for 3rd vs. 1st tertile = 0.55, P<0.001). This association was primarily mediated by small HDL particles (P<0.001). Adding total or small HDL particle concentrations rather than HDL cholesterol to multivariate prediction models improved performance metrics for cardiovascular mortality. The presence of CAD had no impact on the associations between HDL particle concentrations and cardiovascular mortality. Conclusions: High HDL particle concentration is consistently and independently of CAD associated with decreased cardiovascular mortality. Whether the inverse relationship between HDL particle concentration and cardiovascular mortality may be translated into novel therapies is under investigation.