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Adipose tissue dysfunction is defined as an imbalance between pro- and anti-inflammatory adipokines, causing insulin resistance, systemic low-grade inflammation, hypercoagulability, and elevated blood pressure. These can lead to cardiovascular disease and diabetes mellitus type 2. Although quantity of adipose tissue is an important determinant of adipose tissue dysfunction, it can be diagnosed in both obese and lean individuals. This implies that not only quantity of adipose tissue should be used as a measure for adipose tissue dysfunction. Instead, focus should be on measuring quality of adipose tissue, which can be done with diagnostic modalities ranging from anthropometric measurements to tissue biopsies and advanced imaging techniques. In daily clinical practice, high quantity of visceral adipose tissue (reflected in high waist circumference or adipose tissue imaging), insulin resistance, or presence of the metabolic syndrome are easy and low-cost diagnostic modalities to evaluate presence or absence of adipose tissue dysfunction., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background: Apolipoprotein E (APOE) genotypes are associated with different plasma lipid levels. People with the APO ɛ2 genotype can develop a disorder called dysbetalipoproteinemia (DBL). A possible predisposing factor for DBL is adiposity. We evaluated whether and to what extent the APOE genotype modifies the relation between adiposity and lipids in patients with manifest arterial disease and we looked at possible determinants of DBL in ɛ2 homo- and heterozygote patients., Methods: This prospective cohort study was performed in 5450 patients with manifest arterial disease from the Secondary Manifestations of ARTerial disease (SMART) study. The APOE genotype was measured in all patients and revealed 58 ɛ2 homozygotes, 663 ɛ2 heterozygotes, 3181 ɛ3 homozygotes and 1548 ɛ4 carriers. The main dependent variable was non-high-density lipoprotein cholesterol (non-HDL-c). The relation between adiposity (including body mass index (BMI), waist circumference (waist), visceral adipose tissue (VAT) and metabolic syndrome (MetS)) and lipids was evaluated with linear regression analyses. Determinants of DBL were evaluated using logistic regression., Results: There was significant effect modification by the APOE genotype on the relation between non-HDL-c and BMI, waist, VAT and MetS. There was an association between BMI and non-HDL-c in ɛ2 homozygotes (β 0.173, 95% confidence interval (CI) 0.031-0.314, P=0.018) and ɛ4 carriers (β 0.033, 95% CI 0.020-0.046, P<0.001). In all genotypes, there was an effect of waist, VAT and MetS on non-HDL-c, but these effects were most distinct in ɛ2 homozygotes (waist β 0.063, 95% CI 0.015-0.110, P=0.011; VAT β 0.580, 95% CI 0.270-0.889, P=0.001; MetS β 1.760, 95% CI 0.668-2.852, P=0.002). Determinants of DBL in ɛ2 homo- and heterozygotes were VAT and MetS., Conclusion: The APOE genotype modifies the relation between adiposity and plasma lipid levels in patients with vascular disease. The relation between adiposity and lipids is present in all patients, but it is most distinct in ɛ2 homozygote patients. Abdominal fat and MetS are determinants of DBL.

Objectives: A remarkable variation exists in the cardiometabolic consequences of obesity. We evaluated the separate and combined effects of adiposity and cardiometabolic dysfunction on the occurrence of cardiovascular events and mortality in patients with vascular disease., Methods: We prospectively followed 5231 patients with a history of clinical cardiovascular disease without diabetes from the Second Manifestations of ARTerial disease (SMART) study. Patients were classified according to body mass index and cardiometabolic function. The presence of cardiometabolic dysfunction was defined as ≥3 of the modified National Cholesterol Education Program (NCEP) metabolic syndrome criteria (waist circumference replaced by elevated C-reactive protein). Cox proportional-hazards analysis was used to estimate HRs for cardiovascular events and mortality., Results: The prevalence of cardiometabolic dysfunction was 40% in normal weight, 58% in overweight and 75% in obese patients. During a median follow-up of 6.1 years, 769 patients died and 705 patients experienced a major cardiovascular event. In the absence of cardiometabolic dysfunction, overweight (HR 1.18, 95% CI 0.90 to 1.55) and obese patients (HR 0.93, 95% CI 0.53 to 1.64) were not at increased risk of recurrent major cardiovascular events compared with normal weight patients without cardiometabolic dysfunction. An increased cardiovascular risk was observed in patients with cardiometabolic dysfunction and normal weight (HR 1.58, 95% CI 1.23 to 2.04), overweight (HR 1.35, 95% CI 1.07 to 1.70) and obesity (HR 1.50, 95% CI 1.12 to 2.00) compared with normal weight patients without cardiometabolic dysfunction. A similar pattern was observed for vascular and all-cause mortality., Conclusions: In patients with vascular disease, the cardiometabolic consequences of adiposity rather than adiposity per se increase the risk of recurrent cardiovascular events and mortality., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Aims: To assess the effect of various measures of adiposity and of metabolic risk factors, both separately and in combination, on the risk of future Type 2 diabetes in patients with manifest vascular diseases., Methods: This was a prospective cohort study in 2924 patients (mean age 59 ± 12 years) with manifest atherosclerosis. Metabolic risk factors were defined according to National Cholesterol Education Program criteria for the metabolic syndrome. Incidence of Type 2 diabetes was assessed by questionnaire and subsequent verification., Results: During a median follow-up of 4.9 years (range 3.0-7.6 years) there were 178 cases (6.1%) of incident Type 2 diabetes. An increase with 1 sd waist circumference showed a strong association with incident Type 2 diabetes in both men (hazard ratio 2.45, 95% CI 1.97-3.04) and women (hazard ratio 1.77, 95% CI 1.38-2.26). Compared with patients with normal (i.e. below the National Cholesterol Education Program criteria for abdominal adiposity) waist circumference and < 3 metabolic risk factors, both patients with normal waist circumference and ≥ 3 metabolic risk factors and patients with high (i.e. above the National Cholesterol Education Program criteria for abdominal adiposity) waist circumference and < 3 metabolic risk factors had an increased risk of Type 2 diabetes (hazard ratio 2.44, 95% CI 1.37-4.36 and hazard ratio 3.61, 95% CI 2.23-5.85, respectively). Patients with both high waist circumference and ≥ 3 metabolic risk factors had the highest risk of developing Type 2 diabetes (hazard ratio 10.76, 95% CI 6.95-16.64)., Conclusions: In patients with manifest atherosclerosis, both presence of ≥ 3 metabolic risk factors and presence of a high waist circumference alone are associated with increased risk for developing Type 2 diabetes. The combined presence of ≥ 3 metabolic risk factors and high waist circumference, which is present in 15% of patients, is associated with a 10-fold increased risk of future Type 2 diabetes. To identify patients with manifest atherosclerosis at the highest risk of developing Type 2 diabetes, fat distribution in combination with metabolic risk factors should be considered., (© 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.)

Patients with hypertension and manifest vascular disease are at high risk for recurrent cardiovascular diseases. It is unknown if the metabolic syndrome further increases the risk in these patients. This study aims to quantify the effect of metabolic syndrome and type II diabetes on cardiovascular events in hypertensive patients with vascular disease. A total of 2,196 hypertensive patients with vascular disease (cerebrovascular disease (34%), coronary heart disease (50%), peripheral arterial disease (28%), abdominal aortic aneurysm (13%)) from the Second Manifestations of Arterial Disease study were followed for up to 10 years (mean 3.9 years) for death, stroke and myocardial infarction. Age and sex adjusted hazard ratios (HR) were calculated for hypertensive patients with metabolic syndrome but without diabetes (n=775) and for hypertensive patients with type II diabetes (n=381), compared to merely hypertensive patients (n=1,040). Forty-nine percent had metabolic syndrome (NCEP ATPIII definition) and 17% had type II diabetes. Metabolic syndrome predicted vascular death (HR 1.41, 95% confidence interval (CI) 1.01-1.98), stroke (HR 1.36, 95% CI 0.85-2.16) and myocardial infarction (HR 1.40, 95% CI 0.97-2.01). Type II diabetes accounted for even higher risks of vascular end points (HR 1.41-1.64). The effect of metabolic syndrome on future events could not be explained by the presence of type II diabetes. Even in high-risk patients with hypertension and vascular disease, presence of metabolic syndrome or type II diabetes identifies patients at high risk for future cardiovascular events. Identifying metabolic syndrome patients may direct therapy focusing on treatment of insulin resistance by reducing weight and increasing physical activity.

Objective: All factors of the metabolic syndrome (MetS) are reported to be associated with elevated C-reactive protein (CRP) levels. As CRP levels have been found to decrease as a result of statin treatment, the present study was intended to explore the relationship between CRP and the MetS in statin treated patients., Methods: In this study, the relationship between the components of the MetS and CRP level were analysed and factors determining CRP were identified in patients with longstanding intensive lipid lowering therapy with known cardiovascular disease., Results: In this population CRP levels are still associated with the MetS, with waist circumference, fasting glucose level and smoking being the most important determinants of CRP levels., Conclusions: CRP levels are still associated with the MetS in patients treated with intensive lipid lowering therapy.

Objective: Gout and increased serum uric acid (SUA) levels are often seen in patients with components of the metabolic syndrome. Increased SUA levels are associated with increased vascular risk, as is the metabolic syndrome. We investigated the association between SUA levels and the metabolic syndrome in a population of patients with manifest vascular disease to determine whether SUA levels convey an independent risk for vascular disease in patients with the metabolic syndrome., Methods: A nested case-cohort study of 431 patients with 220 cases with a new vascular event during followup, originating from the Second Manifestations of Arterial Disease (SMART) study. All patients had manifest vascular diseases, consisting of cerebral, coronary, or peripheral artery disease or abdominal aortic aneurysm. The relationship of SUA with the metabolic syndrome was analyzed with linear regression and adjusted for age, sex, creatinine clearance, and alcohol and diuretic use. The relationship of SUA levels with new vascular disease was investigated with Cox regression and adjusted for age and sex., Results: The metabolic syndrome was present in 50% of patients. SUA levels were higher in 214 patients with the metabolic syndrome than in 217 patients without (0.36 +/- 0.08 mmol/l vs 0.32 +/- 0.09 mmol/l). SUA concentrations increased with the number of components of the metabolic syndrome (0.30 mmol/l to 0.38 mmol/l) adjusted for age, sex, creatinine clearance, and alcohol and diuretic use. Increased SUA concentrations were independently associated with risk for vascular events in patients without the metabolic syndrome (age and sex adjusted hazard ratio 2.4, 95% CI 1.0-5.5), in contrast to patients with the metabolic syndrome (adjusted hazard ratio 1.9, 95% CI 1.0-3.9)., Conclusion: Elevated SUA levels are strongly associated with the metabolic syndrome, yet are not an independent risk factor for vascular disease in patients with the metabolic syndrome. In patients without the metabolic syndrome, elevated SUA levels are associated with increased risk for vascular disease.

Despite criticism regarding its clinical relevance, the concept of the metabolic syndrome improves our understanding of both the pathophysiology of insulin resistance and its associated metabolic changes and vascular consequences. Free fatty acids (FFA) and tumour necrosis factor-alpha (TNF-alpha) play prominent roles in the development of insulin resistance by impairing the intracellular insulin signalling transduction pathway. Obesity is an independent risk factor for cardiovascular disease and strongly related to insulin resistance. In case of obesity, FFAs and TNF-alpha are produced in abundance by adipocytes, whereas the production of adiponectin, an anti-inflammatory adipokine, is reduced. This imbalanced production of pro- and anti-inflammatory adipokines, as observed in adipocyte dysfunction, is thought to be the driving force behind insulin resistance. The role of several recently discovered adipokines such as resistin, visfatin and retinol-binding protein (RBP)-4 in the pathogenesis of insulin resistance is increasingly understood. Insulin resistance induces several metabolic changes, including hyperglycaemia, dyslipidaemia and hypertension, all leading to increased cardiovascular risk. In addition, the dysfunctional adipocyte, reflected largely by low adiponectin levels and a high TNF-alpha concentration, directly influences the vascular endothelium, causing endothelial dysfunction and atherosclerosis. Adipocyte dysfunction could therefore be regarded as the common antecedent of both insulin resistance and atherosclerosis and functions as the link between obesity and cardiovascular disease. Targeting the dysfunctional adipocyte may reduce the risk for both cardiovascular disease and the development of type 2 diabetes. Although lifestyle intervention remains the cornerstone of therapy in improving insulin sensitivity and its associated metabolic changes, medical treatment might prove to be important as well.

The metabolic syndrome is a cluster of several vascular risk factors (impaired glucose metabolism, dyslipidaemia, hypertension and central adiposity). The prevalence of the metabolic syndrome is high, varying between 10 and 40% depending on age and sex. This prevalence will increase in the years to come due to the increased prevalence of overweight/obesity. To identify the metabolic syndrome, there is a readily applicable definition for daily clinical practice, i.e. the presence of three or more of the following characteristics: hyperglycaemia, hypertension, low plasma HDL cholesterol level, high plasma triglyceride level and central adiposity. The underlying pathophysiology is not fully clarified, but insulin resistance plays an important role in this syndrome. The metabolic syndrome is associated with increased cardiovascular morbidity and mortality and an increased risk for the development of diabetes mellitus type 2. In subjects with one or two components of the metabolic syndrome and in patients with manifest vascular disease, it seems advisable to be alert to the presence of the other components in order to either diagnose or exclude the metabolic syndrome. Although clinical evidence is lacking, from a pathophysiological point of view it seems reasonable to focus the treatment on reducing insulin resistance, which can be achieved by weight reduction and an increase in physical activity. Treatment of the individual risk factors may also be considered, depending on the degree of vascular risk.

Summary Obesity-related hypertension is increasingly recognized as a distinct hypertensive phenotype requiring a modified approach to diagnosis and management. In this review rapidly evolving insights into the complex and interdependent mechanisms linking obesity to hypertension are discussed. Overweight and obesity are associated with adipose tissue dysfunction, characterized by enlarged hypertrophied adipocytes, increased infiltration by macrophages and marked changes in secretion of adipokines and free fatty acids. This results in chronic vascular inflammation, oxidative stress, activation of the renin-angiotensin-aldosterone system and sympathetic overdrive, eventually leading to hypertension. These mechanisms may provide novel targets for anti-hypertensive drug treatment. Recognition of obesity-related hypertension as a distinct diagnosis enables tailored therapy in clinical practice. This includes lifestyle modification and accommodated choice of blood pressure-lowering drugs. [ABSTRACT FROM AUTHOR]