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Background and aims Patients with peripheral arterial disease (PAD) are at high risk for fatal events. We aimed to investigate the ability among several serum proteins to predict all-cause mortality in outpatients with PAD. Methods Consecutive outpatients with carotid and/or lower extremity PAD were included in the discovery cohort (n = 436), and subjects with PAD from a population-based sample in the validation cohort (n = 129). Blood samples were analyzed for 81 proteins by a proximity extension assay. The proteins best predicting incident all-cause mortality were identified using L1-regularized Cox regression. The added value of the identified proteins to clinical risk markers was evaluated by Cox regression models and presented by the area under the receiver operator characteristics curves (AUC). Results In the discovery cohort (mean age 70 years; 59% men), 195 died (4.8 events per 100 person-years) during a 10.3 years median follow-up. The clinical risk markers generated an AUC of 0.70 (95% confidence interval [95%CI] 0.65–0.76). The two serum protein biomarkers with best prediction of all-cause mortality were growth differentiation factor 15 and tumor necrosis factor-related apoptosis-inducing ligand receptor 2. Adding these proteins to the clinical risk markers significantly improved prediction (p Conclusions In a large-sample targeted proteomics assay, we identified two proteins that improved risk prediction beyond the COPART risk score. The use of high-throughput proteomics assays may identify potential biomarkers for improved risk prediction in patients with PAD.

Genetic loci associated with CHD show different relationships with intima-media thickness in the common carotid artery (IMT-CCA) and in the bulb (IMT-bulb). We evaluated if IMT-CCA and IMT-bulb differ also with respect to circulating protein profiles and risk of incident atherosclerotic disease.In three Swedish cohorts (MDC, IMPROVE, PIVUS, total n 7000), IMT-CCA and IMT-bulb were assessed by ultrasound at baseline, and 86 cardiovascular-related proteins were analyzed. In the PIVUS study only, IMT-CCA and IMT-bulb were investigated in relation to incident atherosclerotic disease over 10 years of follow-up.In a meta-analysis of the analysis performed separately in the cohorts, three proteins, matrix metalloproteinase-12 (MMP-12), hepatocyte growth factor (HGF) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), were associated with IMT-CCA when adjusted for traditional cardiovascular risk factors. Five proteins were associated with IMT-bulb (MMP-12, growth/differentiation factor 15 (GDF-15), osteoprotegerin, growth hormone and renin). Following adjustment for cardiovascular risk factors, IMT-bulb was significantly more closely related to incident stroke or myocardial infarction (total number of cases, 111) than IMT-CCA in the PIVUS study (HR 1.51 for 1 SD, 95%CI 1.21-1.87, p 0.001 vs HR 1.17, 95%CI 0.93-1.47, p = 0.16). MMP-12 levels were related to this combined end-point (HR 1.30, 95%CI 1.08-1.56, p = 0.0061).Elevated levels of MMP-12 were associated with both IMT-CCA and IMT-bulb, but other proteins were significantly related to IMT in only one of these locations. The finding that IMT-bulb was more closely related to incident atherosclerotic disease than IMT-CCA emphasizes a difference between these measurements of IMT.

Background and aims: The lysosomal cysteine proteases cathepsin B and S have been implicated in the atherosclerotic process. The present paper investigates the association between serum levels of cathepsin B and S and cardiovascular events and mortality in patients with stable coronary heart disease. Methods: The CLARICOR trial is a randomised, placebo-controlled trial investigating the effect of clarithromycin versus placebo in patients with stable coronary heart disease. The outcome was time to either a cardiovascular event or all-cause mortality. The placebo group was used as discovery sample and the clarithromycin group as replication sample: n = 1998, n = 1979; mean age (years) 65, 65; 31%, 30% women; follow-up for 10 years; number of composite outcomes n = 1204, n = 1220; respectively. We used a pre-defined multivariable Cox regression model adjusting for inflammation, established cardiovascular risk factors, kidney function, and use of cardiovascular drugs. Results: Cathepsin B was associated with an increased risk of the composite outcome in both samples after multivariable adjustment (discovery: multivariable ratio (HR) per standard deviation increase 1.12, 95% confidence interval (CI) 1.05–1.19, p < 0.001, replication; HR 1.14, 95% CI 1.07–1.21, p < 0.001). There was no significant association between cathepsin S and the composite outcome in either the discovery or replication sample after multivariable adjustment (p>0.45). Secondary analyses suggest that cathepsin B was predominantly associated with mortality rather than specific cardiovascular events. Conclusions: Cathepsin B, but not serum cathepsin S, was associated with an increased risk of cardiovascular events in patients with stable coronary heart disease. The clinical implications of our findings remain to be established.

Soluble receptors for tumor necrosis factor alpha (sTNFR1 and sTNFR2) have been associated with cardiovascular diseases, and some evidence points towards a difference in associated risk between men and women. We aimed to study the association between sTNFR1 and sTNFR2 and incident myocardial infarctions (MI) and to explore the influence of established cardiovascular risk factors in men and women.We conducted a nested case control study in three large Swedish cohorts, including 533 myocardial infarction cases, and 1003 age-, sex- and cohort-matched controls. Odds ratios (OR) with 95% confidence intervals (CI) were calculated.An association between circulating sTNFR1 and sTNFR2 and an increased risk for MI was found when comparing cases and controls. The odds ratios were significant after adjustment for established cardiovascular risk factors and C-reactive protein in women (OR 1.44, 95% CI 1.08-1.93 for TNFR1, and 1.61, 95% CI 1.11-2.34 for TNFR2), but was abolished in men. Women with a combination of elevated CRP and values in the upper quartile of TNFR1 or TNFR2 had a 5-fold higher risk of myocardial infarction versus those with normal CRP and values in the lower three quartiles of TNFR1 or TNFR2.As the risk estimates for TNFR1 and TNFR2 were higher and remained significant after adjustments for established cardiovascular risk factors in women but not in men, a potential role for TNFR1 and TNFR2 in identifying women with a higher MI risk is possible. The future clinical role of TNFR1 and TNFR2 in combination with CRP to identify high risk patients for coronary heart disease has yet to be determined.

Cardiovascular diseases account for the largest fraction of smoking-induced deaths. Studies of smoking in relation to cardiovascular-related protein markers can provide novel insights into the biological effects of smoking. We investigated the associations between cigarette smoking and 80 protein markers known to be related to cardiovascular diseases in two community-based cohorts, the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS, n = 969, 50% women, all aged 70 years) and the Uppsala Longitudinal Study of Adult Men (ULSAM, n = 717, all men aged 77 years).Smoking status was self-reported and defined as current smoker, former smoker or never-smoker. Levels of the 80 proteins were measured using the proximity extension assay, a novel PCR-based proteomics technique.We found 30 proteins to be significantly associated with current cigarette smoking in PIVUS (FDR5%); and ten were replicated in ULSAM (p 0.05). Matrix metalloproteinase-12 (MMP-12), growth/differentiation factor 15 (GDF-15), urokinase plasminogen activator surface receptor (uPAR), TNF-related apoptosis-inducing ligand receptor 2 (TRAIL-R2), lectin-like oxidized LDL receptor 1 (LOX-1), hepatocyte growth factor (HGF), matrix metalloproteinase-10 (MMP-10) and matrix metalloproteinase-1 (MMP-1) were positively associated, while endothelial cell-specific molecule 1 (ESM-1) and interleukin-27 subunit alpha (IL27-A) showed inverse associations. All of them remained significant in a subset of individuals without manifest cardiovascular disease.The findings of the present study suggest that cigarette smoking may interfere with several essential parts of the atherosclerosis process, as evidenced by associations with protein markers representing endothelial dysfunction, inflammation, neointimal formation, foam cell formation and plaque instability.

Background and aims We used a proteomics array to simultaneously measure multiple proteins that have been suggested to be associated with atherosclerosis and related them to plaque prevalence in carotid arteries in a human population-based study. Methods In the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS; n = 931, 50% women, all aged 70 years), the number of carotid arteries with plaques was recorded by ultrasound. Levels of 82 proteins were assessed in plasma by a proximity extension assay (Proseek Multiplex CVD, Olink Bioscience, Uppsala, Sweden) and related to carotid measures in a regression framework. Results Following adjustment for multiple testing with Bonferroni correction, seven of the proteins were significantly related to the number of carotid arteries affected by plaques in sex-adjusted models (osteoprotegrin, T-cell immunoglobulin and mucin domain (TIM)-1, growth/differentiation factor 15 (GDF-15), matrix metalloprotease-12 (MMP-12), renin, tumor necrosis factor ligand superfamily member 14 (TNFSF14) and growth hormone). Of these, renin (odds ratio [OR], 1.30; 95% confidence interval [CI], 1.13–1.49 per standard deviation increase), growth hormone (OR, 1.24; 95% CI, 1.08–1.43), osteoprotegerin (OR, 1.22; 95% CI, 1.05–1.43) and TNFSF14 (OR, 1.17; 95% CI, 1.01–1.35) were related to plaque prevalence independently of each other and traditional cardiovascular risk factors. Conclusion A novel targeted proteomics approach using the proximity extension technique discovered several new associations of candidate proteins with carotid artery plaque prevalence in a large human sample.

Diseases with abnormal levels of parathyroid hormone (PTH) and calcium, such as primary and secondary hyperparathyroidism, are associated with an increased risk of cardiovascular morbidity and mortality. However, there is paucity on the association between calcium, PTH and abnormalities in the vascular system in the general population.In the PIVUS study (Prospective Investigation of the Vasculature in Uppsala Seniors), a community based cohort of 70-year old men and women (n = 1016), the associations between s-calcium, p-PTH and endothelial function, arterial stiffness and blood pressures were investigated, adjusting for cardiovascular risk factors and mineral metabolism.In multivariable linear regression models 1 SD increase in calcium was associated with 1.1 units decrease in the stroke volume/pulse pressure ratio and 0.06 decrease in common carotid artery distensibility (p 0.001) indicative of increased arterial stiffness. Further, calcium was associated with increasing calculated central pulse pressure with 1.3 mmHg elevation per 1 SD increase in calcium (p 0.05). 1 SD increase in PTH was associated with 1.9 and 1.0 mmHg increase in intra-arterially measured brachial artery systolic and diastolic blood pressures, respectively (p 0.01), as well as 1.6 and 0.9 mmHg increase in calculated central systolic and diastolic blood pressures (p 0.05). PTH was not associated with arterial stiffness, endothelial function or pulse pressure.In a large community-based sample of elderly, calcium was independently associated with increased arterial stiffness, and PTH independently to intra-arterial peripheral and calculated central blood pressures. The findings indicate a possible link between the vasculature and mineral metabolism.

OBJECTIVES: Urinary cystatin C (u-CysC) is a new biomarker for acute tubular kidney dysfunction and may also indicate chronic tubular dysfunction. Chronic kidney disease is an important cardiovascular risk factor, however it is not known if u-CysC is a risk marker for cardiovascular death. METHODS: The association between u-CysC and cardiovascular mortality was investigated in a Swedish community-based cohort of 604 men aged 78 years. During follow-up (mean 6.7 years), 203 participants died, of which 90 due to cardiovascular causes. RESULTS: High u-CysC (>0.029 mg/mmol Cr) was associated with a more than 2-fold risk of cardiovascular death (multivariable hazard ratio for quintile 5 vs. 1: 2.5, 95% CI 1.2-5.2, P 0.029 mg/mmol Cr) combined had a significantly higher cardiovascular mortality risk compared to participants with one or two of these biomarkers normal (hazard ratio 15, 95% CI: 6.7-36, P

Background and aims Research suggests that the protease cathepsin L is causally involved in atherosclerosis. However, data on cathepsin L as a risk marker are lacking. Therefore, we investigated associations between circulating cathepsin L and cardiovascular mortality. Methods Two independent community-based cohorts were used: Uppsala Longitudinal Study of Adult Men (ULSAM); n = 776; mean age 77 years; baseline 1997–2001; 185 cardiovascular deaths during 9.7 years follow-up, and Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS); n = 993; 50% women; mean age 70 years; baseline 2001–2004; 42 cardiovascular deaths during 10.0 years follow-up. Results Higher serum cathepsin L was associated with an increased risk for cardiovascular mortality in age- and sex-adjusted models in both cohorts (ULSAM: hazard ratio (HR) for 1-standard deviation (SD) increase, 1.17 [95% CI, 1.01–1.34], p = 0.032 PIVUS: HR 1.35 [95% CI, 1.07–1.72], p = 0.013). When merging the cohorts, these associations were independent of inflammatory markers and cardiovascular risk factors, but non-significant adjusting for kidney function. Individuals with a combination of elevated cathepsin L and increased inflammation, kidney dysfunction, or prevalent cardiovascular disease had a markedly increased risk, while no increased risk was associated with elevated cathepsin L, in the absence of these disease states. Conclusions An association between higher serum cathepsin L and increased risk of cardiovascular mortality was found in two independent cohorts. Impaired kidney function appears to be an important moderator or mediator of these associations. Further studies are needed to delineate the underlying mechanisms and to evaluate whether the measurement of cathepsin L might have clinical utility.

Our aim was to examine relations of serum retinol-binding protein 4 (RBP4) to cardiovascular risk factors, and prevalent metabolic syndrome (MetS) and cardiovascular disease (CVD) in a large community-based sample of elderly.We evaluated cross-sectional relations of serum RBP4 to cardiovascular risk factors including anthropometrical measures, blood pressure, lipid measures, fasting glucose and insulin, body fat distribution including truncal fat by dual-energy x-ray absorptiometry (DXA), homeostasis model assessment insulin resistance (HOMA-IR) and prevalent MetS in one thousand eight 70-year old participants (50% women) of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS), and in five hundred seven 82-year old men from Uppsala Longitudinal Study of Adult Men (ULSAM). In ULSAM, we also examined associations with prevalent CVD.RBP4 concentrations were positively correlated with serum triglycerides (r=0.30; P0.0001 in both samples), whereas correlations with body mass index (BMI), waist circumference, sagittal abdominal diameter, total and truncal fat mass, total cholesterol, fasting glucose and HOMA-IR were weak. In multivariable-adjusted models, RBP-4 was associated with MetS (odds ratio (OR), 1.16 and 1.33; 95% confidence interval (CI), 0.99-1.37 and 1.05-1.67 per 1-standard deviation (SD) increase in PIVUS and ULSAM, respectively), and prior cerebrovascular disease (OR, 1.37; 95% CI, 1.00-1.88 per 1-SD increase in ULSAM), but not with prior myocardial infarction.In elderly, RBP4 concentrations were associated with MetS and its components in both sexes, and prior cerebrovascular disease in men. These findings are consistent with the hypothesis that circulating RBP4 could be a marker of metabolic complications and possibly also atherosclerosis and overt CVD.

Most previous studies of associations between insulin sensitivity and common carotid artery (CCA) atherosclerosis have been conducted in small samples, have not used direct measurement of insulin sensitivity, and have yielded inconclusive results. We investigated associations of CCA intima-media thickness (IMT) and diameter (CCA-D) measured by B-mode ultrasound and insulin sensitivity measured by the euglycemic hyperinsulinemic clamp test together with risk factors of the insulin resistance syndrome in a community-based sample of 493 elderly men. The clamp glucose disposal rate was an independent predictor of CCA-IMT in multivariate models adjusting for blood pressure, smoking, serum cholesterol, and body mass index (1% decrease in CCA-IMT for a 1 unit increase in glucose disposal rate, P=0.009). Glucose disposal rate was significantly related to CCA-D in univariate (r=-0.11, P=0.02) but not in multivariate models. In conclusion, this study is the first to establish impaired insulin sensitivity, measured by the euglycemic hyperinsulinemic clamp test, as an independent predictor of CCA-IMT in a population-based sample of elderly men.

Background: Endothelial dysfunction is prevalent among individuals with chronic kidney disease. However, the association between glomerular filtration rate and endothelial function in the community is unclear and needs to be investigated in the general population. Methods: In the community-based Prospective Investigation of the Vasculature of Uppsala Seniors study (PIVUS, n ¼ 952, mean age 70, women 49.3%), we investigated cross-sectional associations between estimated cystatin C-based glomerular filtration rate (eGFR), and 3 measures representing different aspects of endothelial function (endothelial-dependent vasodilation [EDV], endothelial independent vasodilatation [EIDV], and flow-mediated dilatation [FMD]). We also performed pre-specified sub-group analyses in participants with normal eGFR (>60 ml/min/1.73 m 2 ). Results: In the whole cohort, 10 ml/min/1.73 m 2 higher eGFR was associated with 3% higher EDV (p ¼ 0.001) and 2% higher EIDV (p ¼ 0.007), adjusted for age and sex. The associations were attenuated and no longer statistically significant after adjusting for established cardiovascular risk factors. In participants with eGFR >60 ml/min/1.73 m 2 , 10 ml higher eGFR was associated with 2% higher EDV (p ¼ 0.04) after adjusting for sex and age. eGFR was not associated to FMD in any model or sub-sample. Conclusion: This community-based study suggests that eGFR is associated with endothelial function also in persons with normal kidney function, but that this association is largely explained by confounding by established cardiovascular risk factors. Thus, our data do not support the notion of a direct causal interplay between renal and vascular function prior to the development of CKD.