Contribution of visceral fat accumulation to the development of coronary artery disease in non-obese men

Abdominal visceral fat measurement using dual-energy X-ray: association with cardiometabolic risk factors

OBJECTIVE

To examine the association between cardiometabolic risk factors and visceral adipose tissue (VAT) measurements using a dual-energy X-ray absorptiometry (DXA) based approach.

DESIGN AND METHODS

An analysis of cross-sectional relationships between DXA VAT measured using CoreScan (GE Healthcare) and cardiometabolic indicators was conducted on a sample of 939 subjects (541 females and 398 males; average age, 56 years; average BMI, 26 kg/m2) who had previously undergone a total body DXA scan as well as measurements of key cardiometabolic risk factors.

RESULTS

Sex-specific, age-adjusted multivariable regression analysis showed that for both men and women, DXA VAT was significantly associated with increased odds of hypertension, impaired fasting glucose, metabolic syndrome, and type 2 diabetes (P < 0.001). After additional model adjustment for BMI and waist circumference, the odds ratio (per SD change in VAT) for type 2 diabetes was 2.07 for women and 2.25 for men. Similarly, the odds ratio for metabolic syndrome for women was 3.46 and for men was 1.75.

CONCLUSIONS

VAT measured using DXA showed a significant association with cardiometabolic risk factors and disease. These relationships persist after statistical adjustment for age, BMI, and waist circumference. DXA VAT may provide a new accessible option for quantifying VAT-related cardiometabolic risk.

Is obesity a possible modifier of periodontal disease as a chronic inflammatory process? A case-control study

BACKGROUND AND OBJECTIVE

This cross-sectional case-control study was conducted to provide a comparative evaluation of clinical periodontal measurements, together with serum levels of certain bioactive peptides and inflammatory cytokines, in relation to obesity. For this purpose, clinical periodontal measurements and the levels of serum leptin, adiponectin, interleukin-6 (IL-6), C-reactive protein and soluble intercellular adhesion molecule-1 of obese female individuals and their nonobese counterparts were compared.

MATERIAL AND METHODS

Sixty obese (body mass index (BMI) > 30) and 31 nonobese (BMI < 30) female subjects were recruited for the present study. Before any periodontal intervention, serum samples were obtained and full-mouth clinical periodontal measurements were recorded at six sites per tooth. ELISA was used for the biochemical analysis. Data were tested statistically.

RESULTS

Clinical attachment level was significantly higher in the obese group compared with the nonobese control group (p < 0.05). Serum levels of leptin and IL-6 were significantly higher in the obese group (p < 0.05). BMI correlated with the serum levels of inflammatory molecules (p < 0.05), but not with clinical periodontal parameters, in the obese group.

CONCLUSION

In conclusion, obesity does not seem to have a prominent effect on clinical periodontal parameters but it does have many correlations with circulating inflammatory molecules. As suggested in the literature, increased levels of leptin and IL-6 in the obese group might be one explanation for a possible relationship between obesity and periodontal disease. A prospective study is warranted to clarify, in greater detail, the effects of obesity on periodontal health.

Correlation of epicardial fat and anthropometric measurements in Asian-Indians: A community based study

BACKGROUND:

It is increasingly evident that visceral adipose tissue plays a leading role in the pathogenesis of the metabolic syndrome. Unfortunately, accurate quantification of intra-abdominal visceral fat is cumbersome and expensive. Epicardial fat represents the component of visceral fat distributed around the heart, and is readily and non-invasively assessed by echocardiography.

AIMS:

To determine the correlation of epicardial fat with anthropometric parameters in a healthy population of Asian-Indians.

MATERIALS AND METHODS:

A prospective, cross-sectional study was conducted as part of a community outreach program from December to March 2011. Individuals over 18 years of age were included in the study. Anthropometric data was collected for all patients. Epicardial fat was assessed in parasternal long and short axes.

RESULTS:

350 healthy individuals were included in the study. Of them, 66.7% were males. Mean age was 42.7 ± 15.3 years (range 18-84). Mean body-mass index (BMI) and waist circumference were 23.3 ± 4.5 kg/m² (range 15.2-34.3) and 80.2 ± 13.3 cm (range 43-115) respectively. Mean epicardial fat in both axes was 2.6 ± 1.3 mm (range 0.3-7.0). Epicardial fat measured in both axes correlated well with weight (r = 0.399, P < 0.001), waist circumference (r = 0.522, P < 0.001) and BMI (r = 0.471, P < 0.001). Epicardial fat also correlated with age (r = 0.559, P < 0.001).

CONCLUSIONS:

There is an excellent correlation between epicardial fat measured by echocardiography and anthropometric parameters of metabolic syndrome.

Vascular complications and changes in body mass index in Japanese type 2 diabetic patients with abdominal obesity

Background

Although many Asian type 2 diabetic patients have been considered to be not obese and have low capacity of insulin secretion, the proportion of obese patients with visceral fat accumulation has increased in recent years. We found previously considerable number of Japanese non-obese subjects (body mass index (BMI) < 25 kg/m²) with visceral fat accumulation and multiple cardiovascular risk factors. The aim of the study was to investigate the difference in clinical features of type 2 diabetic patients with and without visceral fat accumulation, focusing on vascular complications and changes in BMI.

Methods

We enrolled 88 Japanese hospitalized type 2 diabetic patients. Abdominal obesity represented waist circumference (WC) of ≥85 cm for males and ≥90 cm for females (corresponding to visceral fat area of 100 cm²). Subjects were divided into two groups; with or without abdominal obesity.

Results

Hypertension, dyslipidemia and cardiovascular diseases were significantly more in the patients with abdominal obesity. The prevalence of cardiovascular disease in the non-obese patients (BMI < 25 kg/m²) with abdominal obesity were similar in obese patients (BMI ≥25 kg/m²). The mean BMI of the patients with abdominal obesity was < 25 kg/m² at 20 years of age, but reached maximum to more than 30 kg/m² in the course. Furthermore, substantial portion of the type 2 diabetic patients (52% in males and 43% in females) were not obese at 20 year-old (BMI < 25 kg/m²), but developed abdominal obesity by the time of admission.

Conclusion

These results emphasize the need to control multiple risk factors and prevent atherosclerotic disease in patients with abdominal obesity. The significant weight gain after 20 years of age in patients with abdominal obesity stresses the importance of lifestyle modification in younger generation, to prevent potential development of type 2 diabetes and future atherosclerotic cardiovascular disease.

Pathophysiology of human visceral obesity: an update

Excess intra-abdominal adipose tissue accumulation, often termed visceral obesity, is part of a phenotype including dysfunctional subcutaneous adipose tissue expansion and ectopic triglyceride storage closely related to clustering cardiometabolic risk factors. Hypertriglyceridemia; increased free fatty acid availability; adipose tissue release of proinflammatory cytokines; liver insulin resistance and inflammation; increased liver VLDL synthesis and secretion; reduced clearance of triglyceride-rich lipoproteins; presence of small, dense LDL particles; and reduced HDL cholesterol levels are among the many metabolic alterations closely related to this condition. Age, gender, genetics, and ethnicity are broad etiological factors contributing to variation in visceral adipose tissue accumulation. Specific mechanisms responsible for proportionally increased visceral fat storage when facing positive energy balance and weight gain may involve sex hormones, local cortisol production in abdominal adipose tissues, endocannabinoids, growth hormone, and dietary fructose. Physiological characteristics of abdominal adipose tissues such as adipocyte size and number, lipolytic responsiveness, lipid storage capacity, and inflammatory cytokine production are significant correlates and even possible determinants of the increased cardiometabolic risk associated with visceral obesity. Thiazolidinediones, estrogen replacement in postmenopausal women, and testosterone replacement in androgen-deficient men have been shown to favorably modulate body fat distribution and cardiometabolic risk to various degrees. However, some of these therapies must now be considered in the context of their serious side effects. Lifestyle interventions leading to weight loss generally induce preferential mobilization of visceral fat. In clinical practice, measuring waist circumference in addition to the body mass index could be helpful for the identification and management of a subgroup of overweight or obese patients at high cardiometabolic risk.

IGFBP-3 inhibits cytokine-induced insulin resistance and early manifestations of atherosclerosis

Metabolic syndrome is associated with visceral obesity, insulin resistance and an increased risk of cardiovascular diseases. Visceral fat tissue primarily consists of adipocytes that secrete cytokines leading to a state of systemic inflammation in obese conditions. One of the IGF-independent functions of IGFBP-3 is its role as an anti-inflammatory molecule. Our study in obese adolescents show a decrease in total IGFBP-3 levels and increase in proteolyzed IGFBP-3 in circulation when compared to their normal counterparts and establishes a positive correlation between IGFBP-3 proteolysis and adiposity parameters as well as insulin resistance. In human adipocytes, we show that IGFBP-3 inhibits TNF-α-induced NF-κB activity in an IGF-independent manner, thereby restoring the deregulated insulin signaling and negating TNF-α-induced inhibition of glucose uptake. IGFBP-3 further inhibits TNF-α, CRP and high glucose-induced NF-κB activity in human aortic endothelial cells (HAECs) and subsequently suppresses monocyte adhesion to HAEC through the IGFBP-3 receptor. In conclusion, these findings suggest that reduced levels of IGFBP-3 in circulation and reduced expression of IGFBP-3 in macrophages in obesity may result in suppression of its anti-inflammatory functions and therefore IGFBP-3 may present itself as a therapeutic for obesity-induced insulin resistance and for events occurring in the early stages of atherosclerosis.

Sex and life expectancy

BACKGROUND

A sexual dimorphism in human life expectancy has existed in almost every country for as long as records have been kept. Although human life expectancy has increased each year, females still live longer, on average, than males. Undoubtedly, the reasons for the sex gap in life expectancy are multifaceted, and it has been discussed from both sociological and biological perspectives. However, even if biological factors make up only a small percentage of the determinants of the sex difference in this phenomenon, parity in average life expectancy should not be anticipated.

OBJECTIVE

The aim of this review is to highlight biological mechanisms that may underlie the sexual dimorphism in life expectancy.

METHODS

Using PubMed, ISI Web of Knowledge, and Google Scholar, as well as cited and citing reference histories of articles through August 2012, English-language articles were identified, read, and synthesized into categories that could account for biological sex differences in human life expectancy.

RESULTS

The examination of biological mechanisms accounting for the female-based advantage in human life expectancy has been an active area of inquiry; however, it is still difficult to prove the relative importance of any 1 factor. Nonetheless, biological differences between the sexes do exist and include differences in genetic and physiological factors such as progressive skewing of X chromosome inactivation, telomere attrition, mitochondrial inheritance, hormonal and cellular responses to stress, immune function, and metabolic substrate handling among others. These factors may account for at least a part of the female advantage in human life expectancy.

CONCLUSIONS

Despite noted gaps in sex equality, higher body fat percentages and lower physical activity levels globally at all ages, a sex-based gap in life expectancy exists in nearly every country for which data exist. There are several biological mechanisms that may contribute to explaining why females live longer than men on average, but the complexity of the human life experience makes research examining the contribution of any single factor for the female advantage difficult. However, this information may still prove important to the development of strategies for healthy aging in both sexes.

Oxidative stress is associated with visceral adipose tissue and subclinical atherosclerosis in a healthy multi-ethnic population

Oxidative stress plays an important role in the development of atherosclerosis. Excess visceral adipose tissue (VAT) and increased carotid intima-media thickness (IMT) are risk factors for coronary artery disease. We tested the hypothesis that VAT and IMT were associated with systemic oxidative stress. Healthy men and women (n = 565) matched for ethnicity (Aboriginal, Chinese, European, and South Asian) were recruited. Plasma malondialdehyde, a biomarker of oxidative stress, was measured as thiobarbituric acid reactive substances (TBARS). VAT and IMT were determined by computerized tomography and ultrasound scans, respectively. Plasma TBARS levels correlated with VAT and total atheroma burden (sum of IMT area and plaque area) in the entire cohort. When stratified by ethnicity, plasma TBARS levels correlated with distinct body composition and arterial measures in different ethnic populations with more associations present amongst Chinese and Europeans relative to Aboriginals and South Asians. VAT was associated with plasma TBARS levels independent of age, sex, ethnicity, smoking, and body mass index. Plasma TBARS levels were associated with IMT, the presence of plaques, and total atheroma burden, independent of age, sex, ethnicity, smoking, body mass index, and VAT. The association with total atheroma burden remained significant even when adjusted for apolipoprotein B. Results from the present study indicate that oxidative stress is positively associated with VAT as well as diffuse and focal carotid atherosclerosis in apparently healthy men and women.

Dual-energy X-ray absorptiometry for quantification of visceral fat

Obesity is the major risk factor for metabolic syndrome and through it diabetes as well as cardiovascular disease. Visceral fat (VF) rather than subcutaneous fat (SF) is the major predictor of adverse events. Currently, the reference standard for measuring VF is abdominal X-ray computed tomography (CT) or magnetic resonance imaging (MRI), requiring highly used clinical equipment. Dual-energy X-ray absorptiometry (DXA) can accurately measure body composition with high-precision, low X-ray exposure, and short-scanning time. The purpose of this study was to validate a new fully automated method whereby abdominal VF can be measured by DXA. Furthermore, we explored the association between DXA-derived abdominal VF and several other indices for obesity: BMI, waist circumference, waist-to-hip ratio, and DXA-derived total abdominal fat (AF), and SF. We studied 124 adult men and women, aged 18-90 years, representing a wide range of BMI values (18.5-40 kg/m(2)) measured with both DXA and CT in a fasting state within a one hour interval. The coefficient of determination (r(2)) for regression of CT on DXA values was 0.959 for females, 0.949 for males, and 0.957 combined. The 95% confidence interval for r was 0.968 to 0.985 for the combined data. The 95% confidence interval for the mean of the differences between CT and DXA VF volume was -96.0 to -16.3 cm(3). Bland-Altman bias was +67 cm(3) for females and +43 cm(3) for males. The 95% limits of agreement were -339 to +472 cm(3) for females and -379 to +465 cm(3) for males. Combined, the bias was +56 cm(3) with 95% limits of agreement of -355 to +468 cm(3). The correlations between DXA-derived VF and BMI, waist circumference, waist-to-hip ratio, and DXA-derived AF and SF ranged from poor to modest. We conclude that DXA can measure abdominal VF precisely in both men and women. This simple noninvasive method with virtually no radiation can therefore be used to measure VF in individual patients and help define diabetes and cardiovascular risk.

Liver enzyme and adipocytokine profiles are synergistically associated with insulin resistance: the J-SHIPP study

AIM

Alanine aminotransferase (ALT) and γ-glutamyltransferase (GGT) are associated with insulin resistance and arteriosclerotic disease. Since adiposity raises liver enzyme levels and causes insulin resistance, adipocytokines are thought to underlie the relationship between liver enzymes and insulin resistance. To clarify this hypothesis, we conducted a cross-sectional epidemiological study in a Japanese general population.

METHODS

The study subjects were 903 middle-aged to elderly persons. Plasma levels of adiponectin and leptin were measured, while other clinical parameters were obtained from personal health records of medical check-ups. Insulin resistance was assessed by a homeostasis model assessment index (HOMA-IR).

RESULTS

Plasma levels of ALT (r=0.379, p<0.001), GGT (r=0.225, p<0.001), adiponectin (r= -0.346, p<0.001) and leptin (r=0.369, p<0.001) were significantly correlated with insulin resistance even on subgroup analysis by sex. Further, any combination of liver enzymes and adipocytokines was synergistically associated with insulin resistance (p<0.001) after adjustment for possible covariates (ALT*adiponectin: β=-0.098, p<0.001, ALT*leptin: β=0.129, p<0.001, GGT*adiponectin: β=-0.054, p=0.054, GGT*leptin: β=0.126, p<0.001); however, in simple obese subjects with normal adipocytokine levels, liver enzymes were not associated with insulin resistance (mean HOMA-IR: worsened adipocytokine +/visceral obesity +, 2.01±1.14; +/-, 1.39±0.84; -/+, 1.23± 0.55; -/-, 1.03±0.57; p<0.001).

CONCLUSION

Plasma levels of ALT and GGT were independent determinants of insulin resistance only in subjects with a worsened adipocytokine profile. Use of liver enzyme levels as a marker of insulin resistance requires stratification by adipocytokine profile.

Visceral adiposity as a target for the management of the metabolic syndrome

Atherosclerosis, the underlying cause of atherosclerotic cardiovascular disease (ACVD), develops due not only to a single cardiovascular risk factor but to a variety of complex factors. The concept of the multiple cardiometabolic risk factor clustering syndrome has been proposed as a highly atherogenic state, independent of hypercholesterolemia and smoking. Body fat distribution, especially visceral fat accumulation, is a major correlate of a cluster of diabetogenic, atherogenic, prothrombotic, and proinflammatory metabolic abnormalities referred to as the metabolic syndrome, with dysfunctional adipocytes and dysregulated production of adipocytokines (hypoadiponectinemia). Medical research has focused on visceral adiposity as an important component of the syndrome in Japanese subjects with a mild degree of adiposity compared with Western subjects. For the prevention of ACVD at least in Japan, it might be practical to stratify subjects with multiple risk factors for atherosclerotic cardiovascular disease based on visceral fat accumulation. Visceral fat reduction through health promotion programs using risk factor-oriented approaches may be effective in reducing ACVD events, as well as producing improvement in risks and hypoadiponectinemia. This review article discusses visceral adiposity as a key player in the syndrome. Visceral fat reduction with life-style modification is a potentially useful strategy in the prevention of ACVD in patients with the metabolic syndrome.

Absolute value of visceral fat area measured on computed tomography scans and obesity-related cardiovascular risk factors in large-scale Japanese general population (the VACATION-J study)

BACKGROUND

The management of cardiovascular risk factors is important for prevention of atherosclerotic cardiovascular diseases (ACVD). Visceral fat accumulation plays an important role in the clustering of cardiovascular risk factors, leading to ACVD. The present study investigated the gender- and age-specific relationship between obesity-related cardiovascular risk factor accumulation and computed tomography (CT)-measured fat distribution in a large-scale Japanese general population.

METHODS AND RESULTS

Fat distribution was measured on CT scans in 12,443 subjects (males/females = 10,080/2,363), who underwent medical health check-up at 9 centers in Japan. The investigated obesity-related cardiovascular risk factors were hyperglycemia, dyslipidemia, and elevated blood pressure. Visceral fat area (VFA) for all males and old females showed almost symmetric distribution, while that of young females showed skewed distribution with a marked left shift. Only a small proportion of young females had large visceral fat and cardiovascular risk accumulation. The mean number of risk factors exceeded 1.0 at around 100 cm(2) for VFA in all groups, irrespective of gender, age (cut-off age 55), and BMI (cut-off BMI 25 kg/m(2)).

CONCLUSIONS

In this large-scale Japan-wide general population study, an absolute VFA value of about 100 cm(2) equated with obesity-related cardiovascular risk factor accumulation, irrespective of gender, age, and BMI.

A systematic review and meta-analysis of the effect of aerobic vs. resistance exercise training on visceral fat

It is increasingly recognized that the location of excess adiposity, particularly increased deposition of visceral adipose tissue (VAT), is important when determining the adverse health effects of overweight and obesity. Exercise therapy is an integral component of obesity management, but the most potent exercise prescription for VAT benefit is unclear. We aimed to evaluate the independent and synergistic effects of aerobic exercise (AEx) and progressive resistance training (PRT) and to directly compare the efficacy of AEx and PRT for beneficial VAT modulation. A systematic review and meta-analysis was performed to assess the efficacy of exercise interventions on VAT content/volume in overweight and obese adults. Relevant databases were searched to November 2010. Included studies were randomized controlled designs in which AEx or PRT in isolation or combination were employed for 4 weeks or more in adult humans, where computed tomography (CT) or magnetic resonance imaging (MRI) was used for quantification of VAT pre- and post-intervention. Of the 12196 studies from the initial search, 35 were included. After removal of outliers, there was a significant pooled effect size (ES) for the comparison between AEx therapy and control (-0.33, 95% CI: -0.52 to -0.14; P < 0.01) but not for the comparison between PRT therapy and control (0.09, 95% CI: -0.17 to -0.36; P = 0.49). Of the available nine studies which directly compared AEx with PRT, the pooled ES did not reach statistical significance (ES = 0.23, 95% CI: -0.02 to 0.50; P = 0.07 favouring AEx). The pooled ES did not reach statistical significance for interventions that combined AEx and PRT therapy vs. control (-0.28, 95% CI: -0.69 to 0.14; P = 0.19), for which only seven studies were available. These data suggest that aerobic exercise is central for exercise programmes aimed at reducing VAT, and that aerobic exercise below current recommendations for overweight/obesity management may be sufficient for beneficial VAT modification. Further investigation is needed regarding the efficacy and feasibility of multi-modal training as a means of reducing VAT.

[Study of cardiovascular risk factors in Tunisian patients with recent type 2 diabetes]

OBJECTIVE

To study the frequency of silent myocardial ischemia (SMI) in Tunisian patients with recent type 2 diabetes and identify cardiovascular risk factors directly in relation with SMI.

PATIENTS AND METHODS

One hundred and twenty diabetics and sixty healthy people have benefited from blood sampling, electrocardiogram and exercise test.

RESULTS

The frequency of SMI was 21% in diabetics and 3% in healthy people (P=0.01). Obesity and hypertension were higher in diabetics than in healthy people (P=0.001 and P<10(-4)). Using unvaried analysis for risk factors with the presence of SMI in diabetics, we found that age greater than 60 yrs, male sex, sedentary and smoking were significantly correlated with SMI; respectively P=0.004, 0.01, 0.009 and 0.03. The SMI was found in 37% of diabetics with high blood pressure vs 8% in diabetics with normal blood pressure and was correlated with hypertriglyceridemia, hypoHDLemia and microalbuminuria. Patients with SMI had at least two cardiovascular risk factors apart from diabetes among those: age greater or equal to 60 yrs, male sex, smoking, hypertension, dyslipidemia and family history of early coronaropathy. Chronic inflammation and hyperhomocysteinemia were significantly correlated to SMI; OR=4.2 and 3.8. In addition, SMI was found in one diabetic over three who had bad glycemic control. Using multivariate analysis, only age greater or equal to 60 yrs, smoking, hypertension, hyperhomocysteinemia and hypertriglyceridemia were risk factors directly in relation with SMI in type 2 diabetes.

CONCLUSION

The assessment of global cardiovascular risk from the moment of discovering type 2 diabetes and the early screening of SMI should be necessary.

Relationships between circulating adiponectin levels and fat distribution in obese subjects

AIM

Most studies have reported that circulating levels of adiponectin are negatively correlated with the body mass index (BMI), and hypoadiponectinemia is related to cardiometabolic disorders; however, not all obese subjects have hypoadiponectinemia. The present study investigated circulating adiponectin levels and fat distribution, i.e. subcutaneous fat area (SFA) and visceral fat area (VFA), in obese subjects.

METHODS

Sixty-eight obese Korean subjects underwent fat distribution by computed tomography (CT) scan and laboratory tests including circulating total adiponectin levels (APN) and circulating high molecular weight adiponectin levels (HMW-APN).

RESULTS

Log-APN and log-HMW-APN did not correlate with log-BMI either in obese males or females in this study; however, log-APN significantly and negatively correlated with log-VFA both in obese males (r=-0.691, p=0.009) and females (r=-0.319, p=0.002), and log-HMW-APN also correlated negatively with log-VFA both in obese males (r=-0.650, p=0.016) and females (r=-0.370, p=0.005). Log-VFA was a significant determinant of log-APN and log-HMW-APN in obese subjects. In contrast, neither log-APN nor log-HMW-APN was significantly correlated with log-SFA in obese males and females.

CONCLUSIONS

The present study demonstrated that APN and HMW-APN correlated with VFA, but not BMI and SFA, in obese subjects, and suggest that hypoadiponectinemia may represent dysfunction of adipose tissue in obesity.

Atopic dermatitis causes lipid accumulation in the liver of NC/Nga mouse

Various factors have been reported to influence lipid metabolism and cause metabolic syndrome. However, the influence of allergy on the liver that plays important role of lipid metabolism has not been clarified. The aim of this study was to examine the influence of allergy on lipid metabolism of liver. A model of atopic dermatitis was developed in the NC/Nga mouse using picryl chloride to induce allergy. Lipid metabolism parameters were measured and the mechanism of changes in these parameters was examined using DNA microarray analysis and quantitative reverse transcriptase PCR. Triacylglycerol accumulation was promoted in the liver in the mouse atopic dermatitis model despite reductions in food intake, body weight gain, and serum glucose. As this mechanism, it was thought that atopic dermatitis caused the suppression of fatty acid β-oxidation. These results suggest that atopic dermatitis causes lipid accumulation in the liver.

Psoriasis and metabolic syndrome

Psoriasis is a chronic inflammatory and immune-mediated disease associated with several comorbidities, such as obesity, hypertension, diabetes mellitus, dyslipidemia and cardiovascular disorder. These comorbidities are components of metabolic syndrome. The pathogenesis of metabolic syndrome is supposed to be related to increased levels of adipocytokines, such as tumor necrosis factor-α (TNF-α) and adiponectin. Recent study has revealed a high prevalence of metabolic syndrome in psoriatics compared with other skin diseases. Biologic agents, including anti-TNF-α antibodies, are recommended as the first-line treatment for psoriatics with metabolic syndrome. This article reviews the association of psoriasis and metabolic syndrome in terms of adipocytokines and evaluates the role of biologic agents in the treatment of psoriasis.

Hypoadiponectinemia: A Link between Visceral Obesity and Metabolic Syndrome

Metabolic syndrome (MetS) represents a combination of cardiometabolic risk factors, including visceral obesity, glucose intolerance or type 2 diabetes, elevated triglycerides, reduced HDL cholesterol, and hypertension. MetS is rapidly increasing in prevalence worldwide as a consequence of the “epidemic” obesity, with a considerable impact on the global incidence of cardiovascular disease and type 2 diabetes. At present, there is a growing interest on the role of visceral fat accumulation in the occurrence of MetS. In this review, the effects of adipocytokines and other proinflammatory factors produced by fat accumulation on the occurrence of the MetS have been also emphasized. Accordingly, the “hypoadiponectinemia” has been proposed as the most interesting new hypothesis to explain the pathophysiology of MetS.

Circulating omentin is associated with coronary artery disease in men

OBJECTIVE

Obesity is closely associated with an increased risk for cardiovascular morbidity and mortality. Omentin is a fat-derived secreted factor that is downregulated in obesity. We investigated whether circulating omentin associates with the prevalence of coronary artery disease (CAD).

METHODS

The consecutive 78 male subjects were enrolled from patients who underwent coronary angiography. Sixty one age-matched male subjects served as controls. Plasma omentin concentration was measured by enzyme-linked immunosorbent assay.

RESULTS

Plasma levels of omentin correlated negatively with body mass index (BMI), systolic blood pressure, hemoglobin A1c and total cholesterol levels, and positively with HDL cholesterol and adiponectin levels. Circulating omentin was independently associated with hemoglobin A1c and HDL cholesterol in a multiple regression analysis. Plasma levels of omentin were markedly lower in CAD patients than in control subjects (CAD: 102.8 ± 69.0 ng/ml, control: 454.7 ± 128.6 ng/ml, P < 0.001). Multiple logistic regression analysis with BMI, systolic blood pressure, glucose, hemoglobin A1c, HDL cholesterol, adiponectin and omentin revealed that plasma omentin levels were independently correlated with CAD.

CONCLUSION

These data indicate that low levels of omentin are closely linked with the presence of CAD and that omentin serves as a novel biomarker for CAD.

Randomized, double-blind, controlled, comparative trial of formula food containing soy protein vs. milk protein in visceral fat obesity. -FLAVO study-

BACKGROUND

The purpose of the present study was to clarify the efficacy of soy at reducing visceral fat. A randomized, double-blind, controlled, comparative trial was carried out to compare formula food containing soy protein (SP) to the same food in which soy was replaced with milk protein (MP).

METHODS AND RESULTS

Forty-eight participants were enrolled for the treatment of visceral fat obesity (visceral fat area >100 cm² on computed tomography). The SP formula contained 12 g of SP, 9 g of MP, and other nutrients, and was given for 20 weeks in the morning, while in the MP formula SP was replaced with MP. During the 20 weeks of the trial period, visceral fat area and subcutaneous fat area in the MP group were significantly reduced, while those in the SP group did not change as assessed on analysis of covariance. Although waist circumference was reduced in both the SP and MP groups, body weight and body mass index were significantly reduced only in the MP group. Based on a mixed-effects model, the difference in log-transformed visceral fat profiles between the 2 groups was statistically significant (P<0.05), while a negative relationship was observed between the changes in visceral fat and adiponectin in the MP group (P<0.001), but not in the SP group.

CONCLUSIONS

Formula food containing MP is superior to that containing SP for reducing visceral and subcutaneous fat.

A mixture of the aqueous extract of Garcinia cambogia, soy peptide and L: -carnitine reduces the accumulation of visceral fat mass in rats rendered obese by a high fat diet

The aim of the present study was to investigate the anti-obesity effect of a mixture composed of Garcinia cambogia extract, soypeptide, and L: -carnitine (1.2:0.3:0.02, w/w/w) in rats rendered obese by a high-fat diet (HFD). Sprague-Dawley rats were fed either the high-fat control diet (CD) or the 0.38% mixture-supplemented HFD (CD + M) for 9 weeks. The mixture significantly reduced body weight gain and the accumulation of visceral fat mass in a rat model of HFD-induced obesity. Moreover, the mixture effectively lowered blood and hepatic lipid concentrations and serum glucose, insulin, c-peptide, and leptin levels in rats with HFD-induced obesity. Results from real-time reverse transcription-polymerase chain reaction analyses indicated that the expression levels of leptin, tumor necrosis factor-alpha (TNF-alpha), and sterol regulatory element binding protein 1c (SREBP1c) genes in the epididymal fat tissue of rats fed the CD + M diet were 0.4-, 0.6-, and 0.48-fold, respectively, of those found in the CD rats (P < 0.05), while expression of the uncoupling protein 2 (UCP2) gene in epididymal adipose tissue was 1.25-fold (P < 0.05) of that found in CD rats. In conclusion, a mixture composed of G. cambogia extract, soy peptide, and L: -carnitine attenuated visceral fat accumulation and improved dyslipidemia in a rat model with HFD-induced obesity.

The concept of metabolic syndrome: contribution of visceral fat accumulation and its molecular mechanism

Although abdominal obesity or visceral obesity is considered to be one of the components of metabolic syndrome and to have an important role in a cluster of cardiovascular risks, there is no consensus about the definition and diagnostic criteria for this syndrome, probably because there is considerable disagreement about the location and definition of abdominal obesity or visceral obesity.In this review article, the important role of visceral fat accumulation in the development of a variety of lifestyle-related diseases is shown, including cardiovascular disease based on our clinical studies using CT scans, and the mechanism of these disorders is discussed, focusing on adipocytokines, especially adiponectin.The importance of diagnosing metabolic syndrome, in which visceral fat accumulation plays an essential role in the development of multiple risk factors, should be emphasized because lifestyle modification for the reduction of visceral fat may be very effective for the reduction of risks of this type, namely metabolic syndrome in the narrow sense.

Single-slice epicardial fat area measurement: do we need to measure the total epicardial fat volume?

PURPOSE

The aim of this study was to assess a method for measuring epicardial fat volume (EFV) by means of a single-slice area measurement. We investigated the relation between a single-slice fat area measurement and total EFV.

METHODS AND METHODS

A series of 72 consecutive patients (ages 65 ± 11 years; 36 men) who had undergone cardiac computed tomography (CT) on a 64-slice multidetector scanner with prospective electrocardiographic triggering were retrospectively reviewed. Pixels in the pericardium with a density range from -230 to -30 Hounsfield units were considered fat, giving the per-slice epicardial fat area (EFA). The EFV was estimated by the summation of EFAs multiplied by the slice thickness. We investigated the relation between total EFV and each EFA.

RESULTS

EFAs measured at several anatomical landmarks-right pulmonary artery, origins of the left main coronary artery, right coronary artery, coronary sinus-all correlated with the EFV (r = 0.77-0.92). The EFA at the LMCA level was highly reproducible and showed an excellent correlation with the EFV (r = 0.92).

CONCLUSION

The EFA is significantly correlated with the EFV. The EFA is a simple, quick method for representing the time-consuming EFV, which has been used as a predictive indicator of cardiovascular diseases.

Association between metabolic syndrome and male lower urinary tract symptoms in Japanese subjects using three sets of criteria for metabolic syndrome and International Prostate Symptom Score

OBJECTIVES

To investigate whether the metabolic syndrome is a risk factor for lower urinary tract symptoms (LUTS), as defined by the International Prostate Symptom Score (IPSS).

METHODS

A total of 900 men underwent digital rectal examination of the prostate and completed an IPSS questionnaire. These men had visited our hospital for metabolic screening from April 2008 to March 2009. The IPSS includes scores for 3 questions on voiding symptoms, 3 on storage symptoms, and 1 on postmicturition symptoms. The relationships of the LUTS (determined from the IPSS subscores) with the metabolic syndrome diagnosed using the Japan Society for the Study of Obesity, 2005 National Cholesterol Education Program-Adult Treatment Panel III, and 2005 International Diabetes Federation criteria were examined. The severity of LUTS was compared among the younger, middle-age, and older men (<50, 50-64, and ≥65 years old, respectively) with and without the metabolic syndrome.

RESULTS

A diagnosis of the metabolic syndrome was made in 16.7%, 16.6%, and 11.7% of the men using the Japan Society for the Study of Obesity, 2005 National Cholesterol Education Program-Adult Treatment Panel III, and 2005 International Diabetes Federation criteria, respectively. Regardless of the presence of the metabolic syndrome, aging was significantly associated with an increased rate of moderate or severe LUTS, except for postmicturition symptoms. In the middle-age men, the metabolic syndrome had a significant negative correlation with storage symptoms (odds ratio 0.258-0.426). In the younger and older men, LUTS was observed equally in those with and without the metabolic syndrome.

CONCLUSIONS

A relationship between age and LUTS was observed; however, the metabolic syndrome did not show a clear association with LUTS. Our results suggest that LUTS is associated with aging, regardless of the presence of the metabolic syndrome.

Selective contribution of waist circumference reduction on the improvement of sleep-disordered breathing in patients hospitalized with type 2 diabetes mellitus

OBJECTIVE

Sleep-disordered breathing (SDB) is a potential risk factor for cardiac sudden death. Recent studies have reported that patients with type 2 diabetes mellitus (T2DM) frequently suffer from SDB. Although the roles of hyperglycemia, disturbances of the autonomic nervous system and obesity have been postulated, the factors related to SDB in T2DM, especially those related to improvement of SDB remain unknown. We investigated the significance of waist circumference (WC), representing excess visceral fat, body mass index (BMI), glycemic control and other clinical parameters on SDB in T2DM.

METHODS AND SUBJECTS

Forty inpatients received treatment for T2DM. Overnight cardiorespiratory monitoring and laboratory tests were conducted before and after treatment of T2DM.

RESULTS

The apnea-hypopnea index (AHI) at admission correlated positively with BMI, neck circumference, WC, and systolic and diastolic blood pressures, but not with Log 1,5-anhydro-D-glucitol (1,5-AG) and presence or absence of diabetic neuropathy. Stepwise multiple regression analysis identified BMI and WC as significant determinants of AHI. After 2 or 3 weeks of glucose-lowering therapy, hyperglycemia was controlled and significant reductions in AHI, BMI, WC, 1,5-AG, leptin, high-sensitivity C-reactive protein (hs-CRP), and an oxidative stress marker, thiobarbituric acid reactive substances (TBARS) were observed. The fall in AHI correlated significantly with changes in WC independent of BMI, 1,5-AG, leptin, hs-CRP, and TBARS.

CONCLUSION

Our results demonstrated that reduction of WC correlated with improvement in SDB independent of glycemic control in T2DM, and that abdominal obesity might be a target for the treatment of SDB and prevention of potential cardiovascular diseases in T2DM.

Health education "Hokenshido" program reduced metabolic syndrome in the Amagasaki visceral fat study. Three-year follow-up study of 3,174 Japanese employees

OBJECTIVE

The aim of this study was to evaluate the effects of health checkup and the health education "Hokenshido" program based on the concept that visceral fat accumulation causes metabolic syndrome (MetS), leading to cardiovascular disease (CVD).

METHODS AND SUBJECTS

Based on the Japanese definition of metabolic syndrome, in the annual health checkup for general subjects, the measurement of waist circumference and use of "Where am I?" chart on the way to develop atherosclerosis were introduced. The study group comprised 3,174 Japanese employees [2,440 males (46±11 years, mean ± SD), 734 females (43±10 years)], who underwent annual health checkup in 2003, 2004, and 2005. The medical staff provided "Hokenshido" for subjects assessed as having MetS and/or at high risk for CVD.

RESULTS

The prevalence of the MetS in 2003, 2004 and 2005 decreased in males (20.8%, 17.2%, 14.4%, p<0.001) and females (3.0%, 2.2%, 1.9%, p=0.359), respectively. Among subjects with MetS at baseline, the number of subjects with MetS significantly decreased in males (508, 287, 247, p<0.0001) and females (22, 8, 6, p<0.0001), respectively. Mean waist loss was 1.6 cm in males (<0.0001) and 1.5 cm in females (<0.001). Among subjects with metabolic syndrome at baseline, the mean waist loss was 2.5 cm in males (<0.0001) and 3.9 cm in females (<0.05). Fatal atherosclerotic vascular events were not recorded in this study period.

CONCLUSION

Health check-up and the "Hokenshido" program reduced the prevalence of the MetS, which might lead to prevention of CVD.

Abdominal visceral fat thickness measured by ultrasonography predicts the presence and severity of coronary artery disease

Abdominal visceral fat plays a critical role in the pathogenesis of metabolic syndrome, which is a risk factor for coronary artery disease (CAD). Ultrasonography (US) distinctively quantifies visceral fat and subcutaneous fat. We measured the maximum preperitoneal visceral fat thickness (Vmax) and the minimum subcutaneous fat thickness (Smin) by US in 185 patients who underwent coronary angiography. Although the 144 patients with CAD had larger Vmax (8.8 ± 3.6 vs. 6.4 ± 2.8 mm; p < 0.001) than those without, there was no difference in Smin. Vmax of 6.9 mm or higher was an independent predictor of CAD (odds ratio, 3.710, p = 0.008) by multiple logistic regression analysis. Vmax significantly correlated with the number of diseased vessels. Assessment of abdominal visceral fat by US gives us incremental information beyond conventional risk factors for predicting CAD in routine clinical practice.

Visceral fat accumulation and metabolic risk factor clustering in older adults

OBJECTIVES

To examine the relationship between visceral fat area (VFA) evaluated using computed tomography (CT) scans and the number of metabolic risk factors in older adults.

DESIGN

Cross-sectional study

SETTING

A community clinic in Tokyo, Japan.

PARTICIPANTS

Two hundred eighteen individuals aged 65 and older without impairments in activities of daily living who underwent geriatric health examination (63 men, mean age 74.5 ± 7.1; 155 women, mean age 75.3 ± 6.7).

MEASUREMENTS

VFA was obtained from a cross-sectional image at umbilical level in the supine position using CT scanning. Metabolic syndrome components except waist circumference were measured using the criteria of the International Diabetes Federation.

RESULTS

There was a positive correlation between VFA and number of metabolic risk factors in men and women. Multiple regression analysis demonstrated that only VFA was significantly correlated with number of risk factors in men, whereas age and VFA were significantly correlated in women; body mass index was not correlated with number of metabolic risk factors in men or women. Dyslipidemia and high blood glucose were associated with higher VFA, but high blood pressure was not. There was a negative correlation between VFA and serum adiponectin level and a positive correlation between VFA and homeostasis model assessment of insulin resistance.

CONCLUSION

Visceral fat accumulation is associated with metabolic risk factor clustering even in the elderly population. These results have clinical implications for the management of obesity in older adults.

Polymorphisms of genes coding for ghrelin and its receptor in relation to colorectal cancer risk: a two-step gene-wide case-control study

Background

Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also indicates a role of ghrelin in cancer development.

Methods

We conducted a case-control study to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with colorectal cancer risk. Pairwise tagging was used to select the 11 polymorphisms included in the study. The selected polymorphisms were genotyped in 680 cases and 593 controls from the Czech Republic.

Results

We found two SNPs associated with lower risk of colorectal cancer, namely SNPs rs27647 and rs35683. We replicated the two hits, in additional 569 cases and 726 controls from Germany.

Conclusion

A joint analysis of the two populations indicated that the T allele of rs27647 SNP exerted a protective borderline effect (P_trend = 0.004).

Absolute value of bioelectrical impedance analysis-measured visceral fat area with obesity-related cardiovascular risk factors in Japanese workers

AIM

The accumulation of Visceral fat is known to precede metabolic disorders and atherosclerosis. This study aimed to determine the relationships between body mass index (BMI), waist circumference (WC), estimated visceral fat area (eVFA) measured by bioelectrical impedance analysis (BIA), and obesity-related cardiovascular risk factors.

METHODS

The study population was 2,870 middle-aged Japanese employees (males/females=2,322/ 548), who had undergone a health check-up.

RESULTS

In the receiver operating characteristic (ROC) curve, the cutoff levels yielding maximal sensitivity plus specificity for predicting the prevalence of ≥ 2 risks were, 24.5 kg/m(2) for BMI, 84.6 cm for WC, and 111 cm(2) for eVFA in males, and 23.6 kg/m(2), 81.5 cm, and 67 cm(2) in females. The average number of risk factors was over 1.0 in those with a BMI ≥ 25 kg/m(2) and with a WC ≥ 85 cm for males, ≥ 28 kg/m(2) and ≥ 95 cm respectively for females, and those with an eVFA ≥ 100 cm(2) for both males and females. In males, it was around 1.0 with cutoff levels of BMI, WC, and eVFA from the ROC curve. However, in females, it was around 0.6, because the prevalence of subjects with obesity and multiple risks was very low.

CONCLUSIONS

These results suggested that the cutoff level for visceral fat reduction should be set based on an absolute value of risk factors, rather than a calculated value. In regular health check-up, it may be useful to set an absolute cutoff value for eVFA at 100 cm(2) as criteria to screen for multiple obesity-related cardiovascular risk factors.

SRC-3 deficient mice developed fat redistribution under high-fat diet

An emerging concept suggests that an aberrant distributed body fat is closely linked to the occurrence of metabolic abnormalities. Mice deficient in steroid receptor coactivator-3 (SRC-3) are shown to be protected against high-fat diet (HFD) induced obesity but little is known about whether visceral (VAT) and subcutaneous adipose tissue (SCAT) distribute differently in SRC-3(-/-) mice versus SRC-3(+/+) mice. Here we reported that under HFD, fat redistributed between VAT and subcutaneous area of SRC-3(-/-) mice. When VAT/SCAT weight ratio (VAT/SCAT ratio) was calculated, SRC-3(-/-) mice had significantly elevated VAT/SCAT ratio in HFD versus normal diet (ND), while VAT/SCAT ratio was similar in SRC-3(+/+) mice under ND and HFD. Serological changes in SRC-3(-/-) mice paralleled the altered fat distribution. In SRC-3(-/-) mice, assays on gene expression revealed an increase in adipogenesis in VAT versus SCAT and an elevation in thermogenesis and lipolysis in SCAT versus VAT, which could explain the preferential fat accumulation in SRC-3(-/-) VAT. Our results presented in vivo evidence that SRC-3 deficiency could lead to fat redistribution under HFD in mice and provided new clues to researches on the pathogenesis of fat redistribution.

Pericardial fat is more abundant in patients with coronary atherosclerosis and even in the non-obese patients: evaluation with cardiac CT angiography

Epicardial adipose tissue (EAT) may play an important role for developing an unfavorable cardiovascular risk profile. However, it has not been investigated if EAT is associated with coronary atherosclerosis in non-obese patients. We aimed to evaluate whether EAT is related to coronary atherosclerosis in non-obese patients. Among the consecutive patients who underwent coronary CT angiography(CCTA) with an intermediate pretest likelihood for having coronary artery disease, we excluded the patients whose body mass index (BMI) was over 30 kg/m(2) or whose CCTA image quality was not sufficient for the detection of coronary plaque. The remaining patients were divided into the normal and abnormal groups based on the presence of atherosclerotic plaques as seen on the CCTA images. The cardiovascular risk factors were matched between the two groups. Ultimately, 100 patients were included in the normal group and 100 patients were included in the abnormal group. The pericardial fat area was measured at the subaortic level of the heart on the axial CT images. The pericardial fat area was significantly larger in the abnormal group as compared to the normal group (18.1 +/- 10.2 vs. 14.6 +/- 8.7 cm(2),P = 0.019). Even though the overweight patients(25 </= BMI < 30) were excluded, the pericardial fat area was still significantly larger in the patients with coronary atherosclerotic plaque as compared to that of the patients without coronary atherosclerotic plaque (18.7 +/- 11.5 vs. 13.2 +/- 7.9 cm(2), P = 0.006). Pericardial fat was more abundant in the non-obese patients with coronary atherosclerosis as compared to that of the patients without coronary atherosclerosis,after controlling for the other cardiovascular risk factors.

Adiponectin action from head to toe

Adiponectin, the most abundant protein secreted by white adipose tissue, is known for its involvement in obesity-related disorders such as insulin resistance, type 2 diabetes mellitus and atherosclerosis. Moreover, modulation of the circulating adiponectin concentration is observed in pathologies that are more or less obesity-related, such as cancer and rheumatoid arthritis. The wide distribution of adiponectin receptors in various organs and tissues suggests that adiponectin has pleiotropic effects on numerous physiological processes. Besides its well-known insulin-sensitizing, anti-inflammatory and antiatherosclerotic properties, accumulating evidence suggests that adiponectin may also have anticancer properties and be cardioprotective. A beneficial effect of adiponectin on female reproductive function was also suggested. Since adiponectin has numerous beneficial biological functions, its use as a therapeutic agent has been suggested. However, the use of adiponectin or its receptors as therapeutic targets is complicated by the presence of different adiponectin oligomeric isoforms and production sites, by multiple receptors with differing affinities for adiponectin isoforms, and by cell-type-specific effects in different tissues. In this review, we discuss the known and potential roles of adiponectin in various tissues and pathologies. The therapeutic promise of administration of adiponectin and the use of its circulating levels as a diagnostic biomarker are further discussed based on the latest experimental studies.

Comparison between high-sensitivity C-reactive protein (hs-CRP) and white blood cell count (WBC) as an inflammatory component of metabolic syndrome in Japanese

OBJECTIVE

To compare two systemic inflammatory markers, high-sensitivity C-reactive protein (hs-CRP) and white blood cell count (WBC), as a component of metabolic syndrome (MetS).

METHODS

Data of hs-CRP and WBC from 2,185 Japanese men and 1,383 Japanese women were examined using receiver operating characteristic (ROC) curve for diagnosing MetS and Spearman's correlation coefficients.

RESULTS

The area under ROC curve (AUC) of hs-CRP was 0.71 in men and 0.74 in women. The AUC of WBC was 0.65 in men and 0.69 in women. The optimal cutoff point (sensitivity; specificity) of hs-CRP was 0.40 mg/L (0.69; 0.65) in men and 0.35 mg/L (0.67; 0.72) in women. The optimal cutoff point (sensitivity; specificity) of WBC was 5,600/L(-6) (0.61; 0.61) in men and 5,000/L(-6) (0.65; 0.63) in women. Correlations between obesity parameters, blood pressure, and liver function tests were stronger with hs-CRP than with WBC. But, no correlation between MetS-related risk factors was stronger with WBC than with hs-CRP.

CONCLUSION

Hs-CRP is superior to WBC as an inflammatory component of MetS in Japanese. However, WBC may be useful when hs-CRP is not available because WBC is routinely measured in clinical practice.

Establishment of a concept of visceral fat syndrome and discovery of adiponectin

Although obesity is a major background of life style-related diseases such as diabetes mellitus, lipid disorder, hypertension and cardiovascular disease, the extent of whole body fat accumulation does not necessarily the determinant for the occurrence of these diseases. We developed the method for body fat analysis using CT scan and established the concept of visceral fat obesity, in other word metabolic syndrome in which intra-abdominal visceral fat accumulation has an important role in the development of diabetes, lipid disorder, hypertension and atherosclerosis. In order to clarify the mechanism that visceral fat accumulation causes metabolic and cardiovascular diseases, we have analyzed gene expression profile in subcutaneous adipose tissue and visceral adipose tissue. From the analysis, we found that adipose tissue, especially visceral adipose tissue expressed abundantly the genes encoding bioactive substances such as cytokines, growth factors and complements. In addition to known bioactive substances, we found a novel collagen-like protein which we named adiponectin. Adiponectin is present in plasma at a very high concentration and is inversely associated with visceral fat accumulation. Adiponectin has anti-diabetic, anti-hypertensive and anti-atherogenic properties and recent studies revealed that this protein has an anti-inflammatory and anti-oncogenic function. Therefore hypoadiponectinemia induced by visceral fat accumulation should become a strong risk factor for metabolic and cardiovascular diseases and also some kinds of cancers.In this review article, I would like to discuss the mechanism of life style-related diseases by focusing on the dysregulation of adiponectin related to obesity, especially visceral obesity.