Gerd Östling

A diabetes-predictive amino acid score and future cardiovascular disease

AIMS We recently identified a metabolic signature of three amino acids (tyrosine, phenylalanine, and isoleucine) that strongly predicts diabetes development. As novel modifiable targets for intervention are needed to meet the expected increase of cardiovascular disease (CVD) caused by the diabetes epidemic, we investigated whether this diabetes-predictive amino acid score (DM-AA score) predicts development of CVD and its functional consequences. METHODS AND RESULTS We performed a matched case-control study derived from the population-based Malmö Diet and Cancer Cardiovascular Cohort (MDC-CC), all free of CVD. During 12 years of follow-up, 253 individuals developed CVD and were matched for age, sex, and Framingham risk score with 253 controls. Amino acids were profiled in baseline plasma samples, using liquid chromatography-tandem mass spectrometry, and relationship to incident CVD was assessed using conditional logistic regression. We further examined whether the amino acid score also correlated with anatomical [intima-media thickness (IMT) and plaque formation] and functional (exercise-induced myocardial ischaemia) abnormalities. Compared with the lowest quartile of the DM-AA score, the odds ratio (95% confidence interval) for incident CVD in subjects belonging to quartiles 2, 3, and 4 was 1.27 (0.72-2.22), 1.96 (1.07-3.60), and 2.20 (1.12-4.31) (Ptrend = 0.010), respectively, after multivariate adjustment. Increasing quartile of the DM-AA score was cross-sectionally related to carotid IMT (Ptrend = 0.037) and with the presence of at least one plaque larger than 10 mm(2) (Ptrend = 0.001). Compared with the lowest quartile of the DM-AA score, the odds ratio (95% confidence interval) for inducible ischaemia in subjects belonging to quartiles 2, 3, and 4 was 3.31 (1.05-10.4), 4.24 (1.36-13.3), and 4.86 (1.47-16.1) (Ptrend = 0.011), respectively. CONCLUSION This study identifies branched-chain and aromatic amino acids as novel markers of CVD development and as an early link between diabetes and CVD susceptibility.

Increased Echolucency of Carotid Plaques in Patients With Type 2 Diabetes

Background and Purpose— Diabetes is associated with the presence of moderate to large atherosclerotic carotid plaques. Previous carotid ultrasound studies have associated plaques with low echogenicity with a higher risk of cerebrovascular events. The aim of this study was to evaluate whether patients with type 2 diabetes have different plaque echogenicity than do nondiabetic subjects. Methods— Forty-seven type 2 diabetic and 51 nondiabetic subjects with a carotid plaque in the right artery were included in this study. All patients were born in 1935 to 1936 and were participants in a population-based study. Carotid ultrasonography was performed and the risk factors for cardiovascular disease were determined. Plaque echogenicity was assessed quantitatively on B-mode ultrasound images by standardized gray-scale median values. Results— Gray-scale median values were significantly lower, indicating more echolucent plaques, in patients with type 2 diabetes compared with nondiabetics (37.0±14.8 vs 45.5±15.4, P=0.007). Of the other risk factors studied, only triglycerides were significantly associated with the echogenicity of the plaque. Conclusions— Patients with type 2 diabetes have more echolucent plaques compared with nondiabetic subjects. This might be associated with the higher risk of cardiovascular events among diabetics.

Cadmium exposure and atherosclerotic carotid plaques -Results from the Malmö diet and Cancer study.

BACKGROUND Epidemiological studies indicate that cadmium exposure through diet and smoking is associated with increased risk of cardiovascular disease. There are few data on the relationship between cadmium and plaques, the hallmark of underlying atherosclerotic disease. OBJECTIVES To examine the association between exposure to cadmium and the prevalence and size of atherosclerotic plaques in the carotid artery. METHODS A population sample of 4639 Swedish middle-aged women and men was examined in 1991-1994. Carotid plaque was determined by B-mode ultrasound. Cadmium in blood was analyzed by inductively coupled plasma mass spectrometry. RESULTS Comparing quartile 4 with quartile 1 of blood cadmium, the odds ratio (OR) for prevalence of any plaque was 1.9 (95% confidence interval 1.6-2.2) after adjustment for sex and, age; 1.4 (1.1-1.8) after additional adjustment for smoking status; 1.4 (1.1-1.7) after the addition of education level and life style factors; 1.3 (1.03-1.8) after additional adjustment for risk factors and predictors of cardiovascular disease. No effect modification by sex was found in the cadmium-related prevalence of plaques. Similarly, ORs for the prevalence of small and large plaques were after full adjustment 1.4 (1.0-2.1) and 1.4 (0.9-2.0), respectively. The subgroup of never smokers showed no association between cadmium and atherosclerotic plaques. CONCLUSIONS These results extend previous studies on cadmium exposure and clinical cardiovascular events by adding data on the association between cadmium and underlying atherosclerosis in humans. The role of smoking remains unclear. It may both cause residual confounding and be a source of pro-atherogenic cadmium exposure.

Soluble Urokinase Plasminogen Activator Receptor: A Risk Factor for Carotid Plaque, Stroke, and Coronary Artery Disease

Background and Purpose— Recent studies indicate that the urokinase system could have an important role in atherogenesis and plaque rupture. The relationships among the soluble urokinase plasminogen activator receptor (suPAR), carotid plaque, and incidence of ischemic stroke and coronary artery disease (CAD) events were studied in a prospective cohort. Methods— Occurrence of carotid plaque and plasma levels of suPAR were assessed in 5166 men and women, aged 45 to 68 years, participating in the Malmö Diet and Cancer study. Incidences of ischemic stroke and CAD were monitored during a mean follow-up of 15 years. Results— Subjects with carotid plaque had significantly higher levels of suPAR compared with those without carotid plaque. suPAR was associated with increased incidence of ischemic stroke (hazard ratio [HR] for third versus first tertile, 1.50; 95% confidence interval [CI], 1.06–2.11) and CAD (HR, 1.55; 95% CI, 1.13–2.13) after adjustment for risk factors. The risk factor–adjusted HR for ischemic stroke was 2.21 (95% CI, 1.52–3.22) in subjects with carotid plaque and high suPAR (ie, third tertile) and 1.51 (95% CI, 1.05–2.17) in subjects with carotid plaque and low suPAR compared with those without carotid plaque and low suPAR (reference). High levels of suPAR significantly increased the risk of ischemic stroke and CAD in subjects with carotid plaque. Conclusions— suPAR is associated with increased occurrence of carotid plaque and increased incidence of ischemic stroke and CAD. Presence of both elevated levels of suPAR and carotid plaque increases the risk of ischemic stroke in an additive way.

Elevated Plasma Levels of MMP-12 Are Associated With Atherosclerotic Burden and Symptomatic Cardiovascular Disease in Subjects With Type 2 Diabetes

Objective— Matrix metalloproteinases (MMPs) degrade extracellular matrix proteins and play important roles in development and tissue repair. They have also been shown to have both protective and pathogenic effects in atherosclerosis, and experimental studies have suggested that MMP-12 contributes to plaque growth and destabilization. The objective of this study was to investigate the associations between circulating MMPs, atherosclerosis burden, and incidence of cardiovascular disease with a particular focus on type 2 diabetes mellitus. Approach and Results— Plasma levels of MMP-1, -3, -7, -10, and -12 were analyzed by the Proximity Extension Assay technology in 1500 subjects participating in the SUMMIT (surrogate markers for micro- and macrovascular hard end points for innovative diabetes tools) study, 384 incident coronary cases, and 409 matched controls in the Malmö Diet and Cancer study and in 205 carotid endarterectomy patients. Plasma MMP-7 and -12 were higher in subjects with type 2 diabetes mellitus, increased with age and impaired renal function, and was independently associated with prevalent cardiovascular disease, atherosclerotic burden (as assessed by carotid intima-media thickness and ankle-brachial pressure index), arterial stiffness, and plaque inflammation. Baseline MMP-7 and -12 levels were increased in Malmö Diet and Cancer subjects who had a coronary event during follow-up. Conclusions— The plasma level of MMP-7 and -12 are elevated in type 2 diabetes mellitus, associated with more severe atherosclerosis and an increased incidence of coronary events. These observations provide clinical support to previous experimental studies, demonstrating a role for these MMPs in plaque development, and suggest that they are potential biomarkers of atherosclerosis burden and cardiovascular disease risk.

Non-hemodynamic predictors of arterial stiffness after 17 years of follow-up: the Malmö Diet and Cancer study

Background: Arterial stiffness plays a fundamental role in the development of hypertension and is a risk factor for both cardiovascular disease and mortality. The stiffening that occurs with increasing age has, in numerous cross-sectional studies, been shown to be associated with several cardiovascular risk factors. This observational study aims to characterize the predictive and cross-sectional markers focusing on the non-hemodynamic component of arterial stiffness. Method: In all, 2679 men and women from Malmö, Sweden, were examined at baseline during 1991–1994, and again at follow-up during 2007–2012 (mean age 72 years, 38% men). Follow-up examination included measurement of arterial stiffness by carotid–femoral pulse wave velocity (c-fPWV), after a mean period of 17 years. The associations between c-fPWV and risk markers were calculated with multiple linear regression. Results: The results indicated that for both sexes, waist circumference (&bgr; = 0.17, P < 0.001), fasting glucose (&bgr; = 0.13, P < 0.001), Homeostatic Model Assessment – Insulin Resistance (&bgr; = 0.10, P < 0.001), triglycerides (&bgr; = 0.10, P < 0.001), and high-density lipoprotein cholesterol (&bgr; = −0.08, P < 0.001) were all predictors of cfPWV adjusted for mean arterial pressure and heart rate, as well as for classical cardiovascular risk factors and drug treatment. There were no associations between baseline or follow-up low-density lipoprotein cholesterol, smoking, or eGFR and c-fPWV. Conclusion: The non-hemodynamic cluster of risk markers and predictors of arterial stiffness in a middle-aged population includes abdominal obesity, hyperglycemia, and dyslipidemia, but not smoking and low-density lipoprotein cholesterol. This pattern existed in both sexes.

Digital Photoplethysmography for Assessment of Arterial Stiffness: Repeatability and Comparison with Applanation Tonometry

Introduction Arterial stiffness is an independent risk factor for cardiovascular morbidity and can be assessed by applanation tonometry by measuring pulse wave velocity (PWV) and augmentation index (AIX) by pressure pulse wave analysis (PWA). As an inexpensive and operator independent alternative, photoelectric plethysmography (PPG) has been introduced with analysis of the digital volume pulse wave (DPA) and its second derivatives of wave reflections. Objective The objective was to investigate the repeatability of arterial stiffness parameters measured by digital pulse wave analysis (DPA) and the associations to applanation tonometry parameters. Methods and Results 112 pregnant and non-pregnant individuals of different ages and genders were examined with SphygmoCor arterial wall tonometry and Meridian DPA finger photoplethysmography. Coefficients of repeatability, Bland-Altman plots, intraclass correlation coefficients and correlations to heart rate (HR) and body height were calculated for DPA variables, and the DPA variables were compared to tonometry variables left ventricular ejection time (LVET), PWV and AIX. No DPA variable showed any systematic measurement error or excellent repeatability, but dicrotic index (DI), dicrotic dilatation index (DDI), cardiac ejection elasticity index (EEI), aging index (AI) and second derivatives of the crude pulse wave curve, b/a and e/a, showed good repeatability. Overall, the correlations to AIX were better than to PWV, with correlations coefficients >0.70 for EEI, AI and b/a. Considering the level of repeatability and the correlations to tonometry, the overall best DPA parameters were EEI, AI and b/a. The two pansystolic time parameters, ejection time compensated (ETc) by DPA and LVET by tonometry, showed a significant but weak correlation. Conclusion For estimation of the LV function, ETc, EEI and b/a are suitable, for large artery stiffness EEI, and for small arteries DI and DDI. The only global parameter, AI, showed a high repeatability and the overall best correlations with AIX and PWV.

Association between renin and atherosclerotic burden in subjects with and without type 2 diabetes

BackgroundActivation of the renin-angiotensin-aldosterone-system (RAAS) has been proposed to contribute to development of vascular complications in type 2 diabetes (T2D). The aim of the present study was to determine if plasma renin levels are associated with the severity of vascular changes in subjects with and without T2D.MethodsRenin was analyzed by the Proximity Extension Assay in subjects with (n = 985) and without (n = 515) T2D participating in the SUMMIT (SUrrogate markers for Micro- and Macro-vascular hard endpoints for Innovative diabetes Tools) study and in 205 carotid endarterectomy patients. Vascular changes were assessed by determining ankle-brachial pressure index (ABPI), carotid intima-media thickness (IMT), carotid plaque area, pulse wave velocity (PWV) and the reactivity hyperemia index (RHI).ResultsPlasma renin was elevated in subjects with T2D and demonstrated risk factor-independent association with prevalent cardiovascular disease both in subjects with and without T2D. Renin levels increased with age, body mass index, HbA1c and correlated inversely with HDL. Subjects with T2D had more severe carotid disease, increased arterial stiffness, and impaired endothelial function. Risk factor-independent associations between renin and APBI, bulb IMT, carotid plaque area were observed in both T2D and non-T2D subjects. These associations were independent of treatment with RAAS inhibitors. Only weak associations existed between plasma renin and the expression of pro-inflammatory and fibrous components in plaques from 205 endarterectomy patients.ConclusionsOur findings provide clinical evidence for associations between systemic RAAS activation and atherosclerotic burden and suggest that this association is of particular importance in T2D.

Measures of atherosclerotic burden are associated with clinically manifest cardiovascular disease in type 2 diabetes: a European cross-sectional study

There is a need to develop and validate surrogate markers of cardiovascular disease (CVD) in subjects with diabetes. The macrovascular changes associated with diabetes include aggravated atherosclerosis, increased arterial stiffness and endothelial dysfunction. The aim of this study was to determine which of these factors is most strongly associated with clinically manifest cardiovascular events.

Carotid intima-media thickness is associated with incidence of hospitalized atrial fibrillation

OBJECTIVE Carotid intima-media thickness (IMT) is a measure of arterial thickening and a risk predictor for myocardial infarction and stroke. It is unclear whether IMT also predicts atrial fibrillation (AF). We explored the association between IMT and incidence of first AF hospitalization in a population-based cohort. METHODS IMT was measured in 4846 subjects from the general population (aged 46-68 years, 60% women) without a history of AF, heart failure or myocardial infarction. The Swedish in-patient register was used for retrieval of AF cases. IMT was studied in relation to incidence of AF. RESULTS During a mean follow-up of 15.3 years, 353 subjects (181 men, 172 women, 4.8 per 1000 person-years) were hospitalized with a diagnosis of AF. After adjustment for cardiovascular risk factors, the hazard ratio (HR) for incidence of AF was 1.61 (95% confidence interval (CI): 1.14-2.27) for 4th vs. 1st quartile of IMT in the common carotid artery. This relationship was also independent of occurrence of carotid plaque. The results were similar for IMT in the bifurcation. CONCLUSION Carotid IMT was independently associated with incidence of hospitalized AF in this study of middle-aged subjects from the general population. The results suggest that arterial thickening can predict future AF.