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Aims

To identify novel risk markers for incident heart failure using proteomic profiling of 80 proteins previously associated with cardiovascular pathology.

Methods and results

Proteomic profiling (proximity extension assay) was performed in two community‐based prospective cohorts of elderly individuals without heart failure at baseline: the Prospective Investigation of the Vasculature in Uppsala Seniors [PIVUS, n = 901, median age 70.2 (interquartile range 70.0–70.3) years, 80 events]; and the Uppsala Longitudinal Study of Adult Men [ULSAM, n = 685, median age 77.8 (interquartile range 76.9–78.1) years, 90 events]. Twenty‐nine proteins were associated with incident heart failure in the discovery cohort PIVUS after adjustment for age and sex, and correction for multiple testing. Eighteen associations replicated in ULSAM. In pooled analysis of both cohorts, higher levels of nine proteins were associated with incident heart failure after adjustment for established risk factors: growth differentiation factor 15 (GDF‐15), T‐cell immunoglobulin and mucin domain 1 (TIM‐1), tumour necrosis factor‐related apoptosis‐inducing ligand receptor 2 (TRAIL‐R2), spondin‐1 (SPON1), matrix metalloproteinase‐12 (MMP‐12), follistatin (FS), urokinase‐type plasminogen activator surface receptor (U‐PAR), osteoprotegerin (OPG), and suppression of tumorigenicity 2 (ST2). Of these, GDF‐15, U‐PAR, MMP‐12, TRAIL‐R2, SPON1 and FS were associated with worsened echocardiographic left ventricular systolic function at baseline, while only TIM‐1 was positively associated with worsened diastolic function (P < 0.02 for all).

Conclusion

Proteomic profiling identified several novel associations between proteins involved in apoptosis, inflammation, matrix remodelling, and fibrinolysis with incident heart failure in elderly individuals. Our results encourage additional studies investigating the underlying mechanisms and the clinical utility of our findings.

Background and Purpose-Emerging technologies have made it possible to simultaneously evaluate a large number of circulating proteins as potential new stroke risk markers. Methods-We explored associations between 85 cardiovascular proteins, assessed by a proteomics chip, and incident ischemic stroke in 2 independent cohorts of elderly (Prospective Investigation of the Vasculature in Uppsala Seniors [PIVUS]: n=977; 50% women, mean age=70.1 years, 71 fatal/nonfatal ischemic stroke events during 10.0 years; and Uppsala Longitudinal Study in Adult Men [ULSAM]: n=720, mean age=77.5 years, 75 ischemic stroke events during 9.5 years). The proteomics chip uses 2 antibodies for each protein and a polymerase chain reaction step to achieve a high-specific binding and the possibility to measure multiple proteins in parallel, but gives no absolute concentrations. Results-In PIVUS, 16 proteins were related to incident ischemic stroke using a false discovery rate of 5%. Of these, N-terminal pro-B-type natriuretic peptide (P=0.0032), adrenomedullin (P=0.018), and eosinophil cationic protein (P=0.0071) were replicated in ULSAM after adjustment for established stroke risk factors. In predefined secondary meta-analyses of individual data, interleukin-27 subunit , growth/differentiation factor 15, urokinase plasminogen activator surface receptor, tumor necrosis factor receptor superfamily member 6, macrophage colony-stimulating factor 1, and matrix metalloproteinase-7 were also potential risk markers for ischemic stroke after adjustment for multiple comparisons (P<0.0006). The addition of N-terminal pro-B-type natriuretic peptide, adrenomedullin, and eosinophil cationic protein to a model with established risk factors increased the C-statistic from 0.629 to 0.689 (P=0.001). Conclusions-Our data suggest that large-scale proteomics analysis is a promising way of discovering novel biomarkers that could substantially improve the prediction of ischemic stroke.

Aims: We aimed to investigate whether metabolomic profiling of blood can lead to novel insights into heart failure pathogenesis or improved risk prediction.

Methods: Mass spectrometry-based metabolomic profiling was performed in plasma or serum samples from three community-based cohorts without heart failure at baseline (total n=3,924; 341 incident heart failure events, median follow-up ranging from 4.6 to 13.9 years). Cox proportional hazards models were applied to assess the association of each of the 206 identified metabolites with incident heart failure in the discovery cohorts Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS, n=920) and Uppsala Longitudinal Study of Adult Men (ULSAM, n=1,121). Replication was undertaken in the independent cohort TwinGene (n=1,797). We also assessed whether metabolites could improve the prediction of heart failure beyond established risk factors (age, sex, body mass index, low-density lipoprotein- and high-density lipoprotein-cholesterol, triglycerides, lipid medication, diabetes, systolic and diastolic blood pressure, blood pressure medication, glomerular filtration rate, smoking status, and myocardial infarction prior to or during follow-up).

Results: Higher circulating urobilin and lower sphingomyelin (30:1) were associated with incident heart failure in age- and sex-adjusted models in the discovery and replication sample. The hazard ratio (HR) for urobilin in the replication cohort was estimated to 1.29 per SD unit, 95% confidence interval (CI) 1.03-1.63) and for sphingomyelin (30:1) to 0.72 (95% CI 0.58-0.89). Results remained similar after further adjustment for established heart failure risk factors in meta-analyses of all three cohorts. Urobilin concentrations were inversely associated with left ventricular ejection fraction at baseline in the PIVUS cohort (β= -0.70 (95% CI -1.03-(-0.38)). No improvement in risk prediction was observed when adding the two top metabolites (C-index 0.787 (95% CI 0.752-0.823)) or nine Lasso-selected metabolites (0.790 (95% CI 0.754-0.826)) to a modified Atherosclerosis Risk in Communities (ARIC) heart failure risk score model (0.780 (95% CI 0.745-0.816)).

Conclusions: Our metabolomics study identified associations of circulating levels of the heme breakdown product urobilin, and sphingomyelin (30:1), a cell membrane component involved in signal transduction and apoptosis, with incident heart failure.