Relation of the metabolic syndrome to calcified atherosclerotic plaque in the coronary arteries and aorta

Should Radiologists Comment on Incidental Findings of Vascular Calcifications Found on Abdominal/Pelvic CT in Patients Less Than 50 Years of Age?

RATIONALE AND OBJECTIVES

To evaluate if incidental abdominopelvic calcified atherosclerosis (ACA) in patients under 50 years of age correlates with cardiovascular disease (CVD) risk factors. Most studies evaluating calcific atherosclerosis and associated increased risk of CVD have concentrated on middle age and older populations.

MATERIALS AND METHODS

A retrospective review of 519 emergency department patients, aged 25-50 years, receiving computed tomography (CT) was performed and ACA correlated with lipid panels obtained via chart review. Those with calcified atherosclerosis were subdivided by vessel location and calcification burden (mild, moderate, or severe). Patients were followed for six years. Normality, Wilcoxon-Mann-Whitney, Kruskal-Wallis, and chi-square tests were performed.

RESULTS

Two hundred and sixty-nine patients with incidental ACA on CT and 250 without ACA were studied. Atherosclerotic calcifications had a statistically significant correlation with elevated triglyceride (128 mg/dL vs 105 mg/dL; p = 0.0003) and decreased high-density lipoprotein (38 mg/dL vs 41 mg/dL; p = 0.0032) as compared to the control. Patients with ACA were at higher risk of stroke, heart attack, and death (p < 0.0001) during a six-year follow-up period.

CONCLUSION

Incidental atherosclerotic calcification on abdominopelvic CT in patients under 50 years of age correlated with elevated triglycerides and decreased high-density lipoprotein as well as higher risk of cardiovascular events. Since radiologists may be the first to identify this finding and CVD is the leading cause of US deaths, proper recognition and reporting of calcification is valuable.

Clinical implication of 18F-NaF PET/computed tomography indexes of aortic calcification in coronary artery disease patients: correlations with cardiovascular risk factors

OBJECTIVE

Vascular calcification is known to be associated with cardiovascular risk factors. Recently, F-NaF PET has been reported to be effective for detecting early and active vascular calcification. In this study, correlations between F-NaF PET/computed tomography (CT) findings and cardiovascular risk factors were investigated in patients with suspected coronary artery disease.

PATIENTS AND METHODS

Forty patients with suspected coronary artery disease underwent F-NaF PET/CT. The maximum and overall burden of calcifying activity, and the overall burden of calcium deposition in the descending thoracic aorta (DTA) were measured on F-NaF PET/CT and they were compared with cardiovascular risk factors, particularly, with those related to metabolic syndrome.

RESULTS

The maximum and overall burden of calcifying activity in DTA measured on F-NaF PET were significantly correlated with diabetes mellitus (P = 0.030 and 0.049, respectively) and serum HbA1c level (ρ = 0.433 and 0.344, respectively). In contrast, the overall burden of calcium deposition measured on CT was significantly correlated with hypertension (P < 0.001). The overall burden of calcium deposition was also significantly correlated with metabolic syndrome (P = 0.002) and 10-year cardiovascular disease risk score (P = 0.004) CONCLUSION: F-NaF uptake is closely related to diabetes mellitus, whereas aortic calcification on CT is closely related to hypertension. Although F-NaF uptake in DTA can be a potential prognostic factor, aortic calcification on CT is a more significant prognostic factor for overall cardiovascular risk than F-NaF uptake.

Fractional excretion of phosphorus and vascular calcification in stage 3 chronic kidney disease

The role of renal excretion of Pi in relation to vascular calcification (VC) in patients in the early stages of chronic kidney disease (CKD) is controversial. Thus, we determine the relation between fractional excretion of phosphorus (FEP) and VC, measured using two methods in a cross-sectional study of patients with stage 3 CKD. We recorded demographic data, anthropometry, comorbidities and active treatment. We measured 24-hour urine FEP and, in serum, measured fibroblast growth factor 23 (FGF23), α-Klotho, intact parathyroid hormone (iPTH), calcium and phosphorus. VC was measured by lateral abdominal radiography (Kauppila index (KI)) and CT of the abdominal aorta (measured in Agatston units). In 57% of subjects, abnormal VC was present when measured using CT, and in only 17% using lateral abdominal radiography. Factors associated with VC using CT were age, cardiovascular risk factors, vascular comorbidity, microalbuminuria and levels of FGF23, phosphorus and calcium x phosphorus product (CaxP); although only age (OR 1.25, 95% CI 1.11 to 1.41), smoking (OR 21.2, CI 4.4 to 100) and CaxP (OR 1.21, CI 1.06 to 1.37) maintained the association in a multivariate analysis. By contrast, only age (OR 1.35, 95% CI 1.07 to 1.74), CaxP (OR 1.14, CI 1.13 to 1.92) and FEP (OR 1.07,95% CI 1004 to 1.14) were associated with abnormal VC in the lateral abdominal radiography. In conclusion, in patients with stage 3 CKD, the detection of VC by abdominal CT is more sensitive than conventional X-rays. Moreover, CaxP is associated with cardiovascular risk factors and vascular comorbidity; quantification of FEPi in these patients provides additional clinical information in advanced VC detected by KI.

Chitosan oligosaccharides enhance lipid droplets via down-regulation of PCSK9 gene expression in HepG2 cells

Chitosan oligosaccharides (COS), linear polymers of N-acetyl-D-glucosamine and deacetylated glucosamine, exhibit diverse pharmacological effects such as antimicrobial, antitumor, antioxidant and anti-inflammatory activities. Here, we explored their hypocholesterolemic effects in vivo and the molecular mechanisms of COS in hepatic cells. Our in vivo study of dyslipidemic ApoE^-/- male mice showed that COS treatment of 500 mg kg^-1 d^-1 for 4 weeks clearly reduced the lipid deposits in the aorta and significantly decreased the hepatic proprotein convertase subtilisin/kexin type 9 (PCSK9) protein levels versus HFD groups (p < 0.05). To elucidate the mechanisms behind these effects, the HepG2 cell line was treated with COS. We found that COS (200 μg/ml) increased the amount of cell-surface low-density lipoprotein receptor (LDLR) and enhanced the lipid droplets in HepG2 cells (p < 0.05). The mRNA levels of LDLR and HMG-CoA protein levels were not altered, and the mRNA levels of PCSK9 were down-regulated by COS treatment for 24 h. We also observed that the expression levels of SREBP-2 (125 kD) and HNF-1α were increased in total cell lysates, but nuclear SREBP-2 (nSREBP-2, 68 kD, the active subunit of SREBP-2) levels were decreased and FOXO3a levels increased in nuclear lysates after COS treatment for 24 h. We demonstrated that one of the reasons for regulation of lipid transfer with COS is that FOXO3a levels are up-regulated by COS, leading to a reduction in the PCSK9 promoter binding capacity of HNF-1α and thus suppressing PCSK9 gene expression, up-regulating LDLR levels, and enhancing the lipid droplets in HepG2 cells. In addition, decreased expression of the PCSK9 gene was also contributed to by down-regulation of SREBP-2 by COS. We further confirmed the effect of suppression of PCSK9 expression by COS by utilizing RNA interference to silence HNF-1α and SREBP-2. Finally, to the best of our knowledge, we are the first to demonstrate that PCSK9 expression and LDLR activity are synergistically changed by a combination of HNF-1α and SREBP-2 after COS treatment. Our findings indicate that COS may regulate PCSK9 to modulate hepatic LDLR abundance and activity.

Cardiovascular consequences of metabolic syndrome

The metabolic syndrome (MetS) is defined as the concurrence of obesity-associated cardiovascular risk factors including abdominal obesity, impaired glucose tolerance, hypertriglyceridemia, decreased HDL cholesterol, and/or hypertension. Earlier conceptualizations of the MetS focused on insulin resistance as a core feature, and it is clearly coincident with the above list of features. Each component of the MetS is an independent risk factor for cardiovascular disease and the combination of these risk factors elevates rates and severity of cardiovascular disease, related to a spectrum of cardiovascular conditions including microvascular dysfunction, coronary atherosclerosis and calcification, cardiac dysfunction, myocardial infarction, and heart failure. While advances in understanding the etiology and consequences of this complex disorder have been made, the underlying pathophysiological mechanisms remain incompletely understood, and it is unclear how these concurrent risk factors conspire to produce the variety of obesity-associated adverse cardiovascular diseases. In this review, we highlight current knowledge regarding the pathophysiological consequences of obesity and the MetS on cardiovascular function and disease, including considerations of potential physiological and molecular mechanisms that may contribute to these adverse outcomes.

Tanshinone IIA Modulates Low Density Lipoprotein Uptake via Down-Regulation of PCSK9 Gene Expression in HepG2 Cells

Tanshinone IIA, one of the most pharmacologically bioactive phytochemicals isolated from Salvia miltiorrhiza Bunge, possesses several biological activities such as anti-inflammation, anti-cancer, neuroprotection and hypolipidemic activities. In this study, we aim to investigate the hypocholesterolemic effect of tanshinone IIA in hepatic cells. We demonstrated that tanshinone IIA significantly increased the amount of low-density lipoprotein receptor (LDLR) and LDL uptake activity in HepG2 cells at the post-transcriptional regulation. We further demonstrated that tanshinone IIA inhibited the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA and mature protein, which may lead to an increase the cell-surface LDLR in hepatic cells. We further identified a regulatory DNA element involved in the tanshinone IIA-mediated PCSK9 down-regulation, which is located between the -411 and -336 positions of the PCSK9 promoter. Moreover, we found that tanshinone IIA markedly increased the nuclear forkhead box O3a (FoxO3a) level, enhanced FoxO3a/PCSK9 promoter complexes formation and decreased the PCSK9 promoter binding capacity of hepatocyte nuclear factor 1α (HNF-1α), resulting in suppression of PCSK9 gene expression. Finally, we found that the statin-induced PCSK9 overexpression was attenuated and the LDLR activity was elevated in a synergic manner by combination of tanshinone IIA treatment in HepG2 cells. Overall, our results reveal that the tanshinone IIA modulates LDLR level and activity via down-regulation of PCSK9 expression in hepatic cells. Our current findings provide a molecular basis of tanshinone IIA to develop PCSK9 inhibitors for cholesterol management.

Review: Cardiovascular risk assessment in the metabolic syndrome, screening for subclinical disease, and implications for treatment

he metabolic syndrome is a clustering of risk factors known to promote or increase the risk for development of cardiovascular disease. Approximately 25—35% of the adult population of developed countries are characterised with metabolic syndrome by different definitions. Metabolic syndrome, even in the absence of diabetes, is associated with an increased risk of cardiovascular disease and total mortality, and is related to an increased risk for the development of diabetes. Initial evaluation of coronary heart disease risk involves global risk estimation using Framingham or other algorithms for risk prediction. Given the absence of key metabolic syndrome risk factors (namely obesity, elevated triglycerides, and impaired fasting glucose) in these algorithms, elevations in these factors need to be considered in individual patient risk evaluation. Further, consideration of screening for novel risk factors such as C-reactive protein, as well as subclinical atherosclerosis (from carotid ultrasound, computed tomography, or ankle-brachial index), can further refine the estimation of future cardiovascular disease risk. The presence of subclinical atherosclerosis or elevated levels of C-reactive protein can potentially modify recommended treatment goals for lipid and other cardiovascular risk factors. The American Heart Association and US National Heart Lung and Blood Institute have recently released revised guidelines for the diagnosis and clinical management of metabolic syndrome. This article examines global assessment of cardiovascular risk in persons with metabolic syndrome, the role of screening for subclinical disease in risk assessment, as well as treatment strategies and their implications for reducing cardiovascular risk in those with metabolic syndrome.

Admixture mapping of coronary artery calcification in African Americans from the NHLBI family heart study

Background

Coronary artery calcification (CAC) is an imaging biomarker of coronary atherosclerosis. In European Americans, genome-wide association studies (GWAS) have identified several regions associated with coronary artery disease. However, few large studies have been conducted in African Americans. The largest meta-analysis of CAC in African Americans failed to identify genome-wide significant variants despite being powered to detect effects comparable to effects identified in European Americans. Because CAC is different in prevalence and severity in African Americans and European Americans, admixture mapping is a useful approach to identify loci missed by GWAS.

Results

We applied admixture mapping to the African American cohort of the Family Heart Study and identified one genome-wide significant region on chromosome 12 and three potential regions on chromosomes 6, 15, and 19 that are associated with CAC. Follow-up studies using previously reported GWAS meta-analysis data suggest that the regions identified on chromosome 6 and 15 contain variants that are possibly associated with CAC. The associated region on chromosome 6 contains the gene for BMP-6, which is expressed in vascular calcific lesions.

Conclusions

Our results suggest that admixture mapping can be a useful hypothesis-generating tool to identify genomic regions that contribute to complex diseases in genetically admixed populations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-015-0196-x) contains supplementary material, which is available to authorized users.

PCSK9 inhibition to reduce cardiovascular disease risk: recent findings from the biology of PCSK9

PURPOSE OF REVIEW

Review novel insights into the biology of proprotein convertase subtilisin/kexin 9 (PCSK9) that may explain the extreme efficiency of PCSK9 inhibition and the unexpected metabolic effects resulting from PCSK9 monoclonal antibody therapy, and may identify additional patients as target of therapy.

RECENT FINDINGS

For over 20 years, the practical knowledge of cholesterol metabolism has centered around cellular mechanisms, and around the idea that statin therapy is the essential step to control metabolic abnormalities for cardiovascular risk management. This view has been embraced by the recent AHA/ACC guidelines, but is being challenged by recent studies including nonstatin medications and by the development of a new class of cholesterol-lowering agents that seems destined to early US Food and Drug Administration approval. The discovery of PCSK9 - a circulating protein that regulates hepatic low-density lipoprotein (LDL) receptor and serum LDL cholesterol levels - has led to a race for its therapeutic inhibition. Recent findings on PCSK9 regulation and pleiotropic effects will help identify additional patient groups likely to benefit from the inhibitory therapy and unravel the full potential of PCSK9 inhibition therapy.

SUMMARY

Injectable human monoclonal antibodies to block the interaction between PCSK9 and LDL receptor are demonstrating extraordinary efficacy (LDL reductions of up to 70%) and almost the absence of any side-effects. A more moderate effect is seen on other lipoprotein parameters, with the exception of lipoprotein(a) levels. We describe mechanisms that can explain the effect on lipoprotein(a), predict a potential effect on postprandial triglyderides, and suggest a new category of patients for anti-PCSK9 therapy.

Association of volumetric bone mineral density with abdominal aortic calcification in African ancestry men

SUMMARY

We tested for association between cortical and trabecular volumetric bone mineral density (vBMD) with abdominal aortic calcification (AAC) prevalence in 278 Afro-Caribbean men. AAC was present in 68.3 % of the men. Greater cortical, but not trabecular, vBMD was associated with significantly decreased odds of AAC independent of traditional risk factors.

INTRODUCTION

The aim of this study is to assess the prevalence and correlates of AAC in a sample of 278 Afro-Caribbean men (mean age 56) and to test for a largely unexplored association between cortical and trabecular vBMD with AAC prevalence.

METHODS

Men were recruited consecutively as part of an ongoing prospective cohort study of body composition in men aged 40+. For this analysis, AAC was assessed by computed tomography of the abdomen from L3 to S1. Aortic calcium was scored using the Agatston method, and prevalence was defined as a score ≥10 to rule out false positives. Men also had BMD assessed using peripheral quantitative computed tomography at 4 % (trabecular vBMD) and 33 % (cortical vBMD) of the radius and tibia.

RESULTS

Abdominal aortic calcification was present in 68.3 % of the men. Significant independent predictors of AAC prevalence were increased age, increased BMI, hypertension, and current smoking. Age was the strongest predictor, with each SD (7.8 year) increase in age conferring 2.7 times increased odds of having AAC (P < 0.0001). A one SD greater cortical, but not trabecular, vBMD was associated with a significant decreased odds of AAC prevalence independent of other traditional risk factors (OR 0.65; 95 % CI 0.45-0.92).

CONCLUSIONS

Cortical vBMD is inversely associated with AAC presence. This finding suggests that there may be shared physiology between cortical bone compartment remodeling and vascular calcification.

Divergent determinants of 18F-NaF uptake and visible calcium deposition in large arteries: relationship with Framingham risk score

To compare regional vascular distribution and biological determinants of visible calcium load, as assessed by computed tomography, as well as of molecular calcium deposition as assessed by (18)F-NaF positron emission tomography. Eighty oncologic patients undergoing (18)F-NaF PET/CT scan were included in the study. Cardiovascular-risk stratification was performed according to a simplified version of the Framingham model [including age, diabetes, smoking, systolic blood pressure and body mass index (BMI)]. Arterial (18)F-NaF uptake was measured by drawing regions of interest comprising the arteries on each slice of the transaxial PET/CT and normalized to blood (18)F-NaF activity to obtain the arterial target-to-background ratio (TBR). The degree of arterial calcification (AC) was measured using a software program providing Agatston-like scores. Differences in mean values and regression analysis were tested. Predictors of AC and TBR were evaluated by univariate and multivariate analysis. p value of 0.05 was considered statistically significant. No correlation was documented between regional calcium load and regional TBR in any of the studied arterial segments. Visible calcium deposition was found to be dependent upon age while it was not influenced by all the remaining determinants of cardiovascular risk. By contrast, (18)F-NaF uptake was significantly correlated with all descriptors of cardiovascular risk, with the exception of BMI. Vascular (18)F-NaF uptake displays a different regional distribution, as well as different biological predictors, when compared to macroscopic AC. The tight dependency of tracer retention upon ongoing biological determinants of vascular damage suggests that this tool might provide an unexplored window on plaque pathophysiology.

Coronary artery calcium screening in persons with metabolic syndrome and diabetes: implications for prevention

Abstract Diabetes and metabolic syndrome are major risk factors for coronary heart disease (CHD). Many patients suffering CHD events are not adequately identified by traditional risk assessment, suggesting the need for early detection of subclinical CHD to identify those at highest risk. Coronary artery calcium (CAC) screening has added utility in categorizing patients with intermediate and high risk of CHD events, and a growing body of evidence suggests its use for CHD risk assessment in persons with metabolic syndrome and diabetes mellitus. These studies demonstrate the presence and extent of CAC to be greater in those with these conditions, compared to those without, and that CHD risk varies greatly according to the extent of CAC both in persons with and without metabolic syndrome and diabetes mellitus. More recently, guidelines regarding the use of CAC screening have been extended to those with diabetes mellitus, helping to further stratify those patients that may benefit from more intensive therapy. This review evaluates the role and possible benefits of CAC screening, with a focus on those with metabolic syndrome and diabetes mellitus for evaluating the risk for CHD.

Metabolic syndrome, diabetes, and incidence and progression of coronary calcium: the Multiethnic Study of Atherosclerosis study

OBJECTIVES

This study sought to examine and compare the incidence and progression of coronary artery calcium (CAC) among persons with metabolic syndrome (MetS) and diabetes mellitus (DM) versus those with neither condition.

BACKGROUND

MetS and DM are associated with subclinical atherosclerosis as evidenced by CAC.

METHODS

The MESA (Multiethnic Study of Atherosclerosis) included 6,814 African American, Asian, Caucasian, and Hispanic adults 45 to 84 years of age, who were free of cardiovascular disease at baseline. Of these, 5,662 subjects (51% women, mean age 61.0 ± 10.3 years) received baseline and follow-up (mean 2.4 years) cardiac computed tomography scans. We compared the incidence of CAC in 2,927 subjects without CAC at baseline and progression of CAC in 2,735 subjects with CAC at baseline in those with MetS without DM (25.2%), DM without MetS (3.5%), or both DM and MetS (9.0%) to incidence and progression in subjects with neither MetS nor DM (58%). Progression of CAC was also examined in relation to coronary heart disease events over an additional 4.9 years.

RESULTS

Relative to those with neither MetS nor DM, adjusted relative risks (95% confidence intervals [CI]) for incident CAC were 1.7 (95% CI: 1.4 to 2.0), 1.9 (95% CI: 1.4 to 2.4), and 1.8 (95% CI: 1.4 to 2.2) (all p < 0.01), and absolute differences in mean progression (volume score) were 7.8 (95% CI: 4.0 to 11.6; p < 0.01), 11.6 (95% CI: 2.7 to 20.5; p < 0.05), and 22.6 (95% CI: 17.2 to 27.9; p < 0.01) for those with MetS without DM, DM without MetS, and both DM and MetS, respectively. Similar findings were seen in analysis using Agatston calcium score. In addition, progression predicted coronary heart disease events in those with MetS without DM (adjusted hazard ratio: 4.1, 95% CI: 2.0 to 8.5, p < 0.01) and DM (adjusted hazard ratio: 4.9 [95% CI: 1.3 to 18.4], p < 0.05) among those in the highest tertile of CAC increase versus no increase.

CONCLUSIONS

Individuals with MetS and DM have a greater incidence and absolute progression of CAC compared with individuals without these conditions, with progression also predicting coronary heart disease events in those with MetS and DM.

Direct relationship between cell density and FDG uptake in asymptomatic aortic aneurysm close to surgical threshold: an in vivo and in vitro study

PURPOSE

Conflicting results have been reported about the clinical value of fluorodeoxyglucose (FDG) imaging in predicting the risk of rupture of abdominal aortic aneurysm (AAA). The present study tests the hypothesis that FDG uptake is low in asymptomatic noninflammatory AAA due to the low cell density in aneurysmal walls.

METHODS

Positron emission tomography (PET)/CT imaging was performed in 12 consecutive candidates for AAA surgical repair and in 12 age- and sex-matched controls. At intervention, aneurysmal walls were cut into three sequential blocks. Block A was frozen to cut three 5-μm slices for incubation with 2-3 MBq of FDG for 5 min. Block C was first incubated with the same tracer solution for the same time and subsequently frozen to cut three 5-μm slices. Autoradiographic images were coregistered with immunohistochemical pictures of cell density, type and DNA synthesis as assessed on block B.

RESULTS

No visible uptake in abdominal aorta occurred in any patient or control subject. Immunohistochemistry documented a severe loss of wall structure, with low numbers of cells. Tracer retention directly correlated with overall cell density and with prevalence of cells synthesizing DNA. The metabolic nature of FDG uptake was confirmed by the selective effect of preliminary freezing that decreased tracer content by 90% in regions with high cell density and only by 34% in cold acellular areas.

CONCLUSION

The loss of tissue structure and the marked decrease in cell density account for the low prevalence of positive findings at FDG PET imaging, at least in asymptomatic patients bearing AAAs whose diameter is close to surgical indication.

Myeloid-specific estrogen receptor alpha deficiency impairs metabolic homeostasis and accelerates atherosclerotic lesion development

ERα is expressed in macrophages and other immune cells known to exert dramatic effects on glucose homeostasis. We investigated the impact of ERα expression on macrophage function to determine whether hematopoietic or myeloid-specific ERα deletion manifests obesity-induced insulin resistance in mice. Indeed, altered plasma adipokine and cytokine levels, glucose intolerance, insulin resistance, and increased adipose tissue mass were observed in animals harboring a hematopoietic or myeloid-specific deletion of ERα. A similar obese phenotype and increased atherosclerotic lesion area was displayed in LDL receptor-KO mice transplanted with ERα(-/-) bone marrow. In isolated macrophages, ERα was necessary for repression of inflammation, maintenance of oxidative metabolism, IL-4-mediated induction of alternative activation, full phagocytic capacity in response to LPS, and oxidized LDL-induced expression of ApoE and Abca1. Furthermore, we identified ERα as a direct regulator of macrophage transglutaminase 2 expression, a multifunctional atheroprotective enzyme. Our findings suggest that diminished ERα expression in hematopoietic/myeloid cells promotes aspects of the metabolic syndrome and accelerates atherosclerosis in female mice.

Alanine aminotransferase is associated with metabolic syndrome independently of insulin resistance

BACKGROUND

Few studies have examined the effect of insulin resistance on the association between alanine aminotransferase (ALT) and metabolic syndrome. The association between ALT levels and metabolic syndrome were determined, independently of insulin resistance in Korean populations.

METHODS AND RESULTS

The association between ALT and metabolic syndrome were examined in 28,456 subjects who visited 7 Health Promotion Centers at University Hospitals in Korea from 2006 to 2008. HOMA-IR index was used to represent insulin resistance index. ALT levels were found to be positively associated with metabolic syndrome after adjusting for age, alcohol intake, and smoking status. Furthermore, when additional adjustment was made for insulin resistance, this association between ALT and metabolic syndrome, although slightly attenuated, remained strongly significant. Subjects in the highest ALT quartile were found to have a higher risk of having metabolic syndrome than those in the lowest quartile (odds ratio (OR)=4.45, 95% confidence interval (CI)=3.96-4.99 for men and OR=3.51, 95%CI=2.73-4.52 for women). In addition, the association between ALT level and the risk of metabolic syndrome was significantly higher in the relatively low risk group.

CONCLUSIONS

ALT levels were found to be significantly associated with metabolic syndrome independently of insulin resistance and with an interaction by age. Further cohort studies are needed to determine the usefulness of ALT levels for predicting the risk of metabolic syndrome.

The relationship between metabolic syndrome, its components, and the whole-body atherosclerotic disease burden as measured by computed tomography angiography

OBJECTIVE

Quantify the whole-body atherosclerotic disease in asymptomatic subjects with and without metabolic syndrome (MetS) and to assess the contribution of the syndrome and its components to the atherosclerotic burden.

METHODS

Sixty-five subjects with and 51 without ATPIII-defined MetS underwent a 64-slice computed tomography angiography (CTA). Plaques causing >0% stenosis in coronary or extra-coronary arteries were classified as positive.

RESULTS

The prevalence of plaques in coronary, carotid and peripheral arteries as well as their severity did not differ between groups. Conversely, it was seen an almost 3-fold increased likelihood (OR=2.70; 95% CI 1.30-5.57; P<0.001) of atherosclerosis in any district across categories of MetS components (0-1 vs. 2-3 vs. 4-5). Hypertriglyceridemia (P<0.05) and high blood glucose (P<0.05) were independent predictors of the atherosclerotic burden.

CONCLUSIONS

Atherosclerotic burden as revealed by 64-TCA appears to be more strongly associated with the number of MetS-related factors than to the clinical diagnosis of MetS itself.

The relationship between the cardiometabolic syndrome and coronary artery calcium progression

J Clin Hypertens (Greenwich). 2009;11:505-511. (c)2009 Wiley Periodicals, Inc.Cardiometabolic syndrome has been associated with increased likelihood and extent of coronary artery calcium (CAC). The authors examined the relationship of cardiometabolic syndrome to CAC progression in 200 healthy men who volunteered to undergo repeated electron beam tomography separated by 4.2+/-1.3 years. Prediction of clinically significant CAC progression (>/=15% per year) was evaluated using multivariable logistic regression models and principal component analysis. Clinically significant CAC progression was observed in 52.5% of the cohort, with the mean and median rate of annual progression 41.3% and 18.3%, respectively. The cardiometabolic syndrome in clinically significant CAC progression participants was significantly higher compared with those without CAC progression (24.8% vs 11.6%; P=.016). Cardiometabolic syndrome was a significant independent predictor of clinically significant CAC progression (odds ratio, 2.65; P=.022). Cardiometabolic syndrome is associated with the baseline CAC score, and independently associated with the progression of CAC over 4 years.

Metabolic syndrome and coronary artery calcification in renal transplant recipients

BACKGROUND

Coronary artery calcification (CAC) and metabolic syndrome (MS) have been associated with increased cardiovascular risk. The study objective was to examine the association of MS with CAC presence and progression in renal transplant recipients.

METHODS

We measured the CAC progression in asymptomatic recipients who had no prior history of coronary artery disease.

RESULTS

MS was common (55.4%). Median CAC scores were 0, 33.1, 98, and 261.9 for patients with one, two, three, and four or more positive components of the MS, respectively. Severe CAC scores were more common in recipients with MS (P=0.04). Although recipients with MS had higher mean CAC scores at baseline and significant CAC progression (483 [590.6] vs. 619 [813.8], P=0.01), MS was not an independent predictor of annualized rate of CAC change in a multivariate model.

CONCLUSION

Future studies to evaluate if MS treatment improves cardiovascular outcomes are imperative.

Genome-wide admixture mapping for coronary artery calcification in African Americans: the NHLBI Family Heart Study

Coronary artery calcification (CAC) is an important measure of subclinical coronary atherosclerosis and an independent predictor of coronary heart disease. To identify the genetic loci contributing to CAC, we conducted a genome-wide scan with 374 microsatellite markers by applying admixture mapping to 618 African American participants in the US National Heart, Lung, and Blood Institute Family Heart Study, in which 868 European American participants from family heart study and 157 Africans genotyped by the Marshfield Medical Genetics Center were used as the two reference founding populations for the African Americans, and a computer program based on a Markov Chain Monte Carlo algorithm, STRUCTURE 2.1, was used to estimate European and African ancestries among African Americans. A permutation test for random repeated sampling regression of CAC score on marker specific African ancestry found 22 markers statistically significant at the 0.05 level and four markers, D10S189 at 10p14, D20S159 at 20q13, D12S1294 at 12q14, and D6S1053 at 6q12, significant at the 0.01 level. D10S189 and D6S1053 were further confirmed at the 0.05 significance level by regression of CAC on allelic copy number, in which individual ancestry was used as a genetic background covariate to control possible stratification in African Americans. On the basis of the results from this and other independent studies, the location of D6S1053 at 80cM on chromosome 6 (6q12) seems to harbor a highly promising quantitative trait loci for atherosclerosis.

Relation of the metabolic syndrome to quantity of coronary atherosclerotic plaque

Although metabolic syndrome (MS) is associated with adverse cardiovascular outcomes, its association with the presence and extent of coronary atherosclerotic plaques is not well described. To assess this relation, multidetector computed tomography-based patterns of coronary plaque were assessed in 77 patients enrolled in the ROMICAT study (age 54 +/- 12 years; 79% Caucasians, and 36% women) and compared between those who did (n = 35; 45%) and did not (n = 42; 55%) have MS. The presence of any, calcified, and noncalcified plaque was significantly higher in patients with than without MS (91%, 74%, and 77% vs 46%, 45%, and 40% segments with plaque, respectively; all p <0.01). The overall number of segments with plaques was also higher in patients with MS (5.8 +/- 3.7 vs 2.1 +/- 3.3; p <0.001). MS was independently associated with both the presence and extent of overall plaques after adjusting for the Framingham risk score (odds ratio 6.7, 95% confidence interval 1.6 to 28.8, p <0.01 for presence, beta coefficient = 3.59 +/- 0.88 [SE], p = 0.009 for extent) and individual risk factors, including age, gender, smoking, body mass index, hypertension, diabetes, hyperlipidemia, and clinical coronary disease (odds ratio 8.4, 95% confidence interval 1.7 to 42.5, p = 0.008 for presence, beta coefficient = 2.35 +/- 0.86 [SE], p = 0.007 for extent). Similarly, MS was independently associated with calcified and noncalcified plaques individually. In conclusion, MS was independently associated with the presence and extent of both calcified and noncalcified coronary atherosclerotic plaques detected using multidetector computed tomography. These data may explain the higher cardiovascular risk in these patients and may lay the foundation for studies to determine whether such information may improve risk stratification.

Do inflammation and procoagulation biomarkers contribute to the metabolic syndrome cluster?

Context

The metabolic syndrome (MetS), in addition to its lipid, metabolic, and anthropomorphic characteristics, is associated with a prothrombotic and the proinflammatory state. However, the relationship of inflammatory biomarkers to MetS is not clear.

Objective

To study the association between a group of thrombotic and inflammatory biomarkers and the MetS.

Methods

Ten conventional MetS risk variables and ten biomarkers were analyzed. Correlations, factor analysis, hexagonal binning, and regression of each biomarker with the National Cholesterol Education Program (NCEP) MetS categories were performed in the Family Heart Study (n = 2,762).

Results

Subjects in the top 75% quartile for plasminogen activator inhibitor-1 (PAI1) had a 6.9 CI95 [4.2–11.2] greater odds (p < 0.0001) of being classified with the NCEP MetS. Significant associations of the corresponding top 75% quartile to MetS were identified for monocyte chemotactic protein 1 (MCP1, OR = 2.19), C-reactive protein (CRP, OR = 1.89), interleukin-6 (IL6, OR = 2.11), sICAM1 (OR = 1.61), and fibrinogen (OR = 1.86). PAI1 correlated significantly with all obesity and dyslipidemia variables. CRP had a high correlation with serum amyloid A (0.6) and IL6 (0.51), and a significant correlation with fibrinogen (0.46). Ten conventional quantitative risk factors were utilized to perform multivariate factor analysis. Individual inclusion, in this analysis of each biomarker, showed that, PAI1, CRP, IL6, and fibrinogen were the most important biomarkers that clustered with the MetS latent factors.

Conclusion

PAI1 is an important risk factor for MetS. It correlates significantly with most of the variables studied, clusters in two latent factors related to obesity and lipids, and demonstrates the greatest relative odds of the 10 biomarkers studied with respect to the MetS. Three other biomarkers, CRP, IL6, and fibrinogen associate also importantly with the MetS cluster. These 4 biomarkers can contribute in the MetS risk assessment.

Insulin resistance, metabolic syndrome, and subclinical atherosclerosis: the Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

To investigate the association of insulin resistance and clinically defined metabolic syndrome (MetS) with subclinical atherosclerosis and examine whether these relationships vary by race/ethnicity or sex.

RESEARCH DESIGN AND METHODS

Subclinical atherosclerosis was assessed by coronary artery calcium (CAC) and carotid intima-medial thickness (IMT) in 5,810 participants without diabetes in the Multi-Ethnic Study of Atherosclerosis, a cohort of adults aged 45-84 years without prior cardiovascular disease (CVD). Fasting insulin and glucose were utilized to estimate insulin resistance by the homeostasis model assessment of insulin resistance (HOMA-IR) index, and the revised National Cholesterol Education Program definition of MetS was utilized. Multivariable linear or relative risk regression was used to analyze the association between HOMA-IR and subclinical atherosclerosis and assess its independence from MetS components.

RESULTS

HOMA-IR was associated with increased IMT after adjustment for demographics (age, site, and education), smoking, education, and LDL cholesterol in each ethnic group, except Hispanic subjects, and in both men and women. After further adjusting for nonglucose MetS components, HOMA-IR was not associated with increased IMT. Subjects in the highest quintile of HOMA-IR had an elevated prevalence of CAC in each ethnic group and both sexes, after adjustment for demographics, smoking, and LDL but not after further adjustment for nonglucose MetS components. Among those with detectable CAC, there was no significant relationship between HOMA-IR and the amount of CAC.

CONCLUSIONS

Although HOMA-IR was associated with increased subclinical atherosclerosis, the association was not independent of the risk factors that comprise MetS. Determination of HOMA-IR is unlikely to contribute to improved determination of risk of subclinical CVD.

The Relationship Between Testosterone Levels, the Metabolic Syndrome (by Two Criteria), and Insulin Resistance in a Population of Men with Organic Erectile Dysfunction

INTRODUCTION

Erectile dysfunction (ED) in men increases with age, as does cardiovascular disease (CVD). Major risk factors of CVD are similar to ED, including insulin resistance (IR) and metabolic syndrome (MS). Hypogonadism has been associated with MS and IR in general populations.

AIM

To determine the association between hypogonadism and MS and/or IR in men with ED, and to determine if hypogonadism is related to these cardiovascular (CV) risks.

MAIN OUTCOME MEASURES

To compare the mean testosterone levels in men with and without IR and MS, and to show the difference in hypogonadism prevalence in mutually exclusive definitions of MS.

METHODS

Mean testosterone for the National Cholesterol Education Program (NCEP) and the World Health Organization (WHO) criteria of MS were calculated using independent t-tests. Multiple range t-tests were used to compare and contrast four groups: (i) only NCEP-Third Adult Treatment Panel criteria; (ii) only the WHO criteria; (iii) men with no MS; and (iv) men fulfilling both MS definitions. Chi-squared analysis was employed to determine the association of hypogonadism with IR.

RESULTS

The prevalence of IR was 79% and of MS was 35 % by the WHO but 43% by the NCEP. Differences in point prevalences were negligible when mutually exclusive groups of MS were compared. Mean free testosterone was lower for the WHO MS or the WHO and NCEP MS (P = 0.04) but not for only the NCEP MS criteria. IR was significantly associated with low free testosterone and hypogonadism (P = 0.02 for each). If more than one criteria were present for either the WHO or NCEP MS, free testosterone was lower (P = 0.02).

CONCLUSION

MS and IR are strongly associated with lower testosterone and hypogonadism. The WHO criteria are a more sensitive indicator of MS and may predict ED better. Men with ED should not only have CV risks evaluated, but should also have testosterone levels drawn.

Effect of simvastatin (80 mg) on coronary and abdominal aortic arterial calcium (from the coronary artery calcification treatment with zocor [CATZ] study)

We tested the hypothesis that, compared with placebo, simvastatin would reduce the progression of coronary artery calcium (CAC) and abdominal aortic calcium (AAC) levels in participants asymptomatic for vascular disease. Total CAC and AAC were measured with multidetector cardiac computed tomography. Inclusion criteria were a CAC score of >or=50 Agatston units, high-density lipoprotein (HDL) cholesterol level<or=50 mg/dl, low-density lipoprotein (LDL) cholesterol level between 100 and 160 mg/dl, and >or=2 other risk factors. Diabetes and history of vascular disease were exclusion criteria. Participants were randomized to receive 80 mg simvastatin (n=40) or matching placebo (n=40) for 12 months. Lipids were measured at 3-month intervals, and CAC and AAC measurements were repeated at 6 and 12 months. Total cholesterol, triglycerides, and LDL decreased significantly with simvastatin treatment (p<0.0001 for all comparisons, adjusted for baseline levels), whereas lipids remained unchanged for subjects randomized to receive placebo. Total CAC volume increased from baseline in both treatment groups. For subjects in the active treatment group, CAC volume increased by 9%, whereas in the placebo group, plaque volume increased by 5% (p=0.12 for treatment effect). AAC volume also increased in both treatment groups (p=0.15 for treatment effect). In conclusion, simvastatin treatment does not reduce progression of CAC or AAC compared with placebo.

Metabolic Syndrome: An Evolving Threat in the Genesis of Coronary Artery Disease

Cardiovascular disease is an escalating worldwide health problem. Effective tools to predict and prevent its development and progression are needed. Correctly diagnosing the metabolic syndrome, which identifies people at higher risk for developing diabetes mellitus and cardiovascular disease, may be valuable in guiding treatment and prevention of these major disorders. Several important definitions of the metabolic syndrome have been proposed. The authors discuss these definitions and how they vary in terms of their relationship to incident cardiovascular disease, type 2 diabetes mellitus, and surrogate markers of atherosclerosis. Establishing clarity on what is meant by the metabolic syndrome and agreement as to its underlying basis is needed to reach consensus between the many different definitions that have been proposed. This is particularly the case if it is to become a useful adjunct in clinical practice to identify those who may benefit from more intensive lifestyle interventions and more detailed short-term risk assessments.

High blood pressure in pregnancy and coronary calcification

A considerable proportion of pregnant women develop high blood pressure in pregnancy. Although it is assumed that this condition subsides after pregnancy, many of these women develop the metabolic syndrome later in life and are at increased risk to develop coronary heart disease. Atherosclerosis development is considered in between risk factors and occurrence of vascular symptoms. We set out to cross-sectionally study the relation of high blood pressure during pregnancy with risk of coronary calcification. The study population was composed 491 healthy postmenopausal women selected from a population-based cohort study. Information on high blood pressure during pregnancy was obtained using a questionnaire. Between 2004 and 2005, the women underwent a multidetector computed tomography (Philips Mx 8000 IDT 16) to assess coronary calcium. The Agatston score, volume, and mass measurements were used to quantify coronary calcium. A total of 30.7% of the women reported to have had high blood pressure in pregnancy. Body mass index (odds ratio [OR]: 1.05; 95% CI: 1.01 to 1.09) and diastolic blood pressure (OR: 1.03; 95% CI: 1.01 to 1.05) were significantly related to a history of high blood pressure in pregnancy. Age was significantly related to increased coronary calcification. Women with a history of high blood pressure during pregnancy had a 57% increased risk of having coronary calcification compared with those women without this condition (OR: 1.57; 95% CI: 1.04 to 2.37). After adjusting for age, the relation did not change (OR: 1.64; 95% CI: 1.07 to 2.53). We concluded that high blood pressure during pregnancy is associated with an increased risk of coronary calcification later in life.

Metabolic syndrome: cardiovascular risk assessment and management

The metabolic syndrome (MetS) is a clustering of risk factors known to promote or increase the risk for development of diabetes mellitus and cardiovascular disease (CVD). Approximately one-third of the adult population of developed countries can be categorized as having MetS by different definitions. MetS, even in the absence of diabetes mellitus, is associated with an increased risk of CVD and total mortality. Those with diabetes mellitus are considered a cardiovascular risk equivalent and warrant aggressive management of underlying risk factors to optimize prevention of CVD. Initial evaluation of coronary heart disease risk involves global risk estimation using Framingham or other algorithms for risk prediction. Consideration of screening for novel risk factors such as C-reactive protein, as well as subclinical atherosclerosis (from carotid ultrasound, computed tomography, or ankle-brachial index), can further refine the estimation of future CVD risk. The presence of subclinical atherosclerosis or elevated levels of C-reactive protein can potentially modify recommended treatment goals for lipid and other cardiovascular risk factors. The American Heart Association and US National Heart Lung and Blood Institute have released guidelines for the clinical management of MetS, which focus on lifestyle management for abdominal obesity and physical inactivity, and clinical management of atherogenic dyslipidemia, elevated BP, elevated glucose, and prothrombotic state.

Longitudinal and age trends of metabolic syndrome and its risk factors: the Family Heart Study

Background

We report longitudinal changes in the metabolic syndrome (MetS) in 2,458 participants from 480 families in the Family Heart Study. Participants were examined between 1994–96 (FHS-T1) and 2002–03 (FHS-T2), about 7.4 years apart. Additionally, the impact of medication on estimates of MetS prevalence, and associations of MetS with prevalent coronary heart disease (CHD) and type 2 diabetes (T2D) were studied.

Methods

Three definitions for MetS prevalence were considered. One represented the original (o) National Cholesterol Education Program (NCEP) MetS criteria. Two others considered the confounding of medications effects, respectively (m) lipid medications constituted a categorical diagnostic criterion for lipids variables, and (c) lipids and blood pressure variables were corrected with average clinical trials medications effects. Logistic regression of MetS on CHD and T2D, as well as the trend analysis of MetS by age, were performed.

Results

MetS increased from 17.1% in FHS-T1(o) to 28.8% in FHS-T2(o); from 19.7% in FHS-T1(m) to 42.5% in FHS-T2(m); and from 18.4% in FHS-T1(c) to 33.6% in FHS-T2(c). While we observed adverse changes in all risk factors, the greatest increase was for waist circumference (25%). The percentages of MetS were about 2 to almost 3 times higher in ages 50 years and older than in younger ages. The odds of having prevalent CHD were about 2.5 times higher in the subjects classified with MetS than without.

Conclusion

MetS percentages increased noticeably longitudinally and cross-sectionally with older age. These conclusions were reached with and without considering medication use, but correcting risk factors for medications use affects the MetS prevalence estimates. As found in other studies, MetS was associated with increased odds for prevalent CHD.

Is alcohol consumption associated with calcified atherosclerotic plaque in the coronary arteries and aorta?

BACKGROUND

The goal was to investigate the relation of alcohol consumption to the presence of calcified atherosclerotic plaque in the coronary arteries (CAC) and aorta. Previous results have been conflicting, showing increases, decreases, or no effect of alcohol on risk of calcified plaque.

METHODS

We evaluated the relation of alcohol intake to presence of CAC and calcified plaque in the aorta among 3166 white and African American subjects from the NHLBI Family Heart Study who underwent cardiac computed tomography scans.

RESULTS

With adjustments for age, race, study center, body mass index, hyperglycemia/diabetes, hypertension, and smoking, odds ratios (and 95% CI) for CAC scores >100 in nondrinkers and consumers of 1 to 3, 4 to 7, 8 to 14, and >14 drinks per week were 1.0, 0.8 (0.4, 1.3), 1.1 (0.6, 1.9), 0.9 (0.5, 1.5), and 1.5 (0.9, 2.5), respectively, for men and 1.0, 0.9 (0.5, 1.6), 1.3 (0.8, 2.3), 1.3 (0.7, 2.2), and 2.1 (0.8, 5.9) for women. Sensitivity analyses with other cut-points for calcification gave similar results. Analyses of alcohol and aortic calcification showed similar, nonsignificant associations.

CONCLUSIONS

Despite its frequently demonstrated beneficial effects on coronary artery disease risk, alcohol consumption in this study was not associated with calcified atherosclerotic plaque in the coronary arteries or in the aorta. This suggests that its effects on cardiovascular risk may occur through mechanisms other than those associated with the development of calcified plaque.

Screening and risk stratification of patients with the metabolic syndrome and diabetes

The metabolic syndrome is a clustering of risk factors known to promote or increase the risk for development of cardiovascular disease. Recent estimates demonstrate that approximately one-third of the adult population of developed countries are characterized with metabolic syndrome by different definitions. Metabolic syndrome, even in the absence of diabetes, is associated with an increased risk of cardiovascular disease and total mortality, as well as an increased risk for the development of diabetes. Patients with diabetes are considered a cardiovascular risk equivalent, and warrant aggressive management of underlying risk factors to optimize prevention of cardiovascular disease. Initial evaluation of coronary heart disease risk involves global risk estimation using Framingham or other algorithms for risk prediction. Furthermore, consideration of screening for novel risk factors, such as C-reactive protein, as well as subclinical atherosclerosis (as assessed by carotid ultrasound, computed tomography or ankle-brachial index), can further refine the estimation of future cardiovascular disease risk. The presence of subclinical atherosclerosis or elevated levels of C-reactive protein can potentially modify recommended treatment goals for lipid and other cardiovascular risk factors.