Novel associations between bioavailable estradiol and adipokines in elderly women with different phenotypes of obesity: implications for atherogenesis

Associations between the serum levels of selected bone turnover markers and biological traits in nursing home women aged 80+ without inflammation. A pilot study

BACKGROUND

Bone turnover markers (BTM) reflect the status of bone remodeling processes responsible for bone mineral density. The existing body of evidence that osseous tissue can interact with many other body tissues and organs suggests that the cross-talks can lead to different relationships. The biological traits associated with BTMs have not been thoroughly studied in the elderly despite bone turnover being known to increase with age.

OBJECTIVE

To determine whether the C-terminal crosslinking telopeptides of type I collagen (CTXI) and the serum levels of total (TAP) and bone-specific (BAP) alkaline phosphatase are associated with the biological traits in nursing home women aged 80-92 years without inflammation and, if so, to indicate the best predictors of these BTM's blood concentrations.

METHODS

A group of 64 female volunteers aged 80 years and older, the residents of nursing homes, were screened for the study. Fifty two women were ineligible as they met the exclusion criteria. As a result, the study group consisted of 12 participants (85.1 ± 3.9 years; 58.1 ± 8.7 kg; 1.52 ± 0.06 m), all having blood C-reactive protein (CRP) levels below 3 mg/l. Also assessed were the participants' morphology, glucose and insulin levels, lipid profiles, CTXI, TAP, and BAP. Other measured parameters included body composition, resting heart rate and arterial blood pressure, isometric knee extension peak torque (IKEPT), and walking capacity (6-min walk test). The statistical analysis was performed using Pearson's correlation coefficients, the Benjamini-Hochberg procedure, and a stepwise multiple regression analysis with backward elimination.

RESULTS

Inverse correlations were found between CTX-I and hemoglobin concentration (HGB) (r = -0.680; p = .015), red blood cells count (RBC) (r = -0.664; p = .019), fat-free mass (r = -0.633; p = .027), body weight (r = -0.589; p = .044), and total cholesterol (r = -0.581; p = .048). The multiple regression analysis of CTX-I showed that body weight was the only independent variable that was statistically significant (r2 = 0.346; p < .05; SEE = 0.347 ng/ml). BAP was positively correlated with double product (DP) (r = 0.742; p = .006), RBC (r = 0.650; p = .022), HGB (r = 0.637; p = .026), mean arterial pressure (MAP) (r = 0.622; p = .031), diastolic blood pressure (DBP) (r = 0.612; p = .034), body height (r = 0.603; p = .038), IKEPT (r = 0.565; p = .056), and systolic blood pressure (SBP) (r = 0.538; p = .071). BAP, a dependent variable, was the most closely correlated with DP (r² = 0.550; p < .01; SEE = 9.161 U/l). TAP was also significantly associated with DP (r = 0.775; p = .003), with the association being stronger than between BAP and DP (r² = 0.600; p < .01; SEE = 1000.5 beats/min*mm Hg).

CONCLUSIONS

In relatively healthy the oldest-old nursing home women without inflammation, total body weight was the best predictor of bone resorption shown by the CTX-I concentration, whereas the rate pressure product (DP) turned out to best predict osteoblastic activity determinable from serum alkaline phosphatase activity. The results of the study suggest that the activity of serum TAP and BAP can be enhanced by different mechanisms.

Obesity, Bioactive Lipids, and Adipose Tissue Inflammation in Insulin Resistance

Obesity is a major risk factor for the development of insulin resistance and type 2 diabetes. The exact mechanism by which adipose tissue induces insulin resistance is still unclear. It has been demonstrated that obesity is associated with the adipocyte dysfunction, macrophage infiltration, and low-grade inflammation, which probably contributes to the induction of insulin resistance. Adipose tissue synthesizes and secretes numerous bioactive molecules, namely adipokines and cytokines, which affect the metabolism of both lipids and glucose. Disorders in the synthesis of adipokines and cytokines that occur in obesity lead to changes in lipid and carbohydrates metabolism and, as a consequence, may lead to insulin resistance and type 2 diabetes. Obesity is also associated with the accumulation of lipids. A special group of lipids that are able to regulate the activity of intracellular enzymes are biologically active lipids: long-chain acyl-CoAs, ceramides, and diacylglycerols. According to the latest data, the accumulation of these lipids in adipocytes is probably related to the development of insulin resistance. Recent studies indicate that the accumulation of biologically active lipids in adipose tissue may regulate the synthesis/secretion of adipokines and proinflammatory cytokines. Although studies have revealed that inflammation caused by excessive fat accumulation and abnormalities in lipid metabolism can contribute to the development of obesity-related insulin resistance, further research is needed to determine the exact mechanism by which obesity-related insulin resistance is induced.

Sex Differences in Age-Associated Type 2 Diabetes in Rats-Role of Estrogens and Oxidative Stress

Females live longer than males, and the estrogens are one of the reasons for this difference. We reported some years ago that estrogens are able to protect rats against oxidative stress, by inducing antioxidant genes. Type 2 diabetes is an age-associated disease in which oxidative stress is involved, and moreover, some studies show that the prevalence is higher in men than in women, and therefore there are sex-associated differences. Thus, the aim of this study was to evaluate the role of estrogens in protecting against oxidative stress in type 2 diabetic males and females. For this purpose, we used Goto-Kakizaki rats, which develop type 2 diabetes with age. We found that female diabetic rats showed lower glycaemia levels with age than did diabetic males and that estrogens enhanced insulin sensitivity in diabetic females. Moreover, glucose uptake, measured by positron emission tomography, was higher in the female brain, cerebellum, and heart than in those from male diabetic rats. There were also sex-associated differences in the plasma metabolic profile as determined by metabolomics. The metabolic profile was similar between estrogen-replaced and control diabetic rats and different from ovariectomized diabetic rats. Oxidative stress is involved in these differences. We showed that hepatic mitochondria from females produced less hydrogen peroxide levels and exhibited lower xanthine oxidase activity. We also found that hepatic mitochondrial glutathione oxidation and lipid oxidation levels were lower in diabetic females when compared with diabetic males. Ovariectomy induced oxidative stress, and estrogen replacement therapy prevented it. These findings provide evidence for estrogen beneficial effects in type 2 diabetes and should be considered when prescribing estrogen replacement therapy to menopausal women.

Metabolic Syndrome is Associated with Ceramide Accumulation in Visceral Adipose Tissue of Women with Morbid Obesity

OBJECTIVE

Accelerated transmembrane transport of long-chain fatty acids dependent on fatty acid transporters is responsible for lipid accumulation and, eventually, the development of metabolic syndrome. This study determined the content of lipids (ceramide [CER], diacylglycerol [DAG], triacylglycerol, and free fatty acid [FFA]) and the expression of fatty acid translocase (FAT/CD36) and plasma membrane fatty acid-binding protein in visceral adipose tissue (VAT) and subcutaneous adipose tissue of women with morbid obesity without metabolic syndrome (MetSx-) or with metabolic syndrome (MetSx+) and compared the results with those of lean controls without metabolic syndrome.

METHODS

Lipid content and fatty acid composition in each lipid subclass were estimated by gas liquid chromatography. For total, plasma membrane, and mitochondrial expression of fatty acid transporters, subfractionation with subsequent Western blot technique was used.

RESULTS

A greater content of triacylglycerol in VAT of participants with obesity (MetSx-) was found. However, only the MetSx+ subjects had increased content of CER in VAT in relation to subcutaneous adipose tissue in MetSx+ and lean individuals. This was accompanied by increased total and membrane expression of FAT/CD36 in VAT in MetSx+ subjects. Accordingly, mitochondrial expression of FAT/CD36 and plasma membrane fatty acid-binding protein was decreased in both groups of subjects with obesity.

CONCLUSIONS

Metabolic syndrome is associated with the accumulation of CER in VAT, possibly related to increased FAT/CD36 protein expression.

Metabolic Health in Severely Obese Subjects: A Descriptive Study

BACKGROUND

The prevalence of metabolically healthy obese (MHO) subjects among morbidly obese subjects is poorly described.

AIM

To describe the prevalence of metabolically healthy subjects in a group of morbidly obese referred for bariatric surgery.

METHODS

Descriptive cross-sectional study, 1209 subjects (825 women/384 men) mean body mass index (BMI) of 45.6 (range: 35-72.6) kg/m² and mean age of 42.9 (range: 18-72) years were included. Metabolically unhealthy obese subjects had at least two metabolic risk factors: systolic blood pressure >130 mmHg or diastolic blood pressure >85 mmHg or use of antihypertensive medication, diagnosed diabetes with a HbA1c >6.5% (>48 mmol/mol) or use of antidiabetic medication, high plasma triglycerides or low plasma high-density lipoprotein, or use of lipid-lowering medication. MHO subjects had one or no metabolic risk factors.

RESULTS

Thirty-four percent (413/1209) were characterized as MHO subjects. The MHO stage was characterized by female sex, younger age, and lower neck and waist circumferences. The odds ratio of metabolic unhealthy was 1.12 (1.07-1.17, P < 0.001) and 1.02 (1.01-1.04, P < 0002) for every 1 cm increase in neck and waist circumferences, respectively, and 0.94 (0.91-0.97, P < 0.001) for every 1 U increase in BMI and 1.04 (1.03-1.05, P < 0.001) for every 1 year increase in age.

CONCLUSIONS

Among severely obese subjects, 34% were classified as having a metabolically healthy state, which was more likely to occur in females, younger individuals and was associated with a lower neck and waist circumferences, younger age, and higher BMI. Whether a group of MHO subjects will remain healthy lifelong is unknown.

OA phenotypes, rather than disease stage, drive structural progression--identification of structural progressors from 2 phase III randomized clinical studies with symptomatic knee OA

BACKGROUND/PURPOSE

The aim of this study was to identify key characteristics of disease progression through investigation of the association of radiographic progression over two years with baseline Joint Space Width (JSW), Kellgren-Lawrence (KL) grade, Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, Joint Space Narrowing (JSN), and BMI.

METHODS

Data from 2206 subjects (4390 knees) were combined for this post-hoc analysis of two randomized, double-blind, multi-center, placebo-controlled phase III trials (NCT00486434 and NCT00704847) that evaluated the efficacy and safety of 2-years treatment with oral salmon calcitonin of subjects with painful knee osteoarthritis (OA).

RESULTS

There was a clear positive and significant correlation between KL grade and WOMAC pain and total WOMAC, albeit the variance in pain measures was from min-to-max for all KL categories, emphasizing the heterogeneity of this patient population and pain perception. 32% of target knees did not progress, and only 51% had changes over minimum significant change (MSC). BMI, KL-Score and WOMAC pain was diagnostic, but only KL-score and pain had prognostic value, albeit pain in a non-linear manner.

CONCLUSION

These data clearly describe significant associations between KL grade, JSW, pain and BMI in patients with symptomatic knee OA. KL grade, BMI and WOMAC pain were diagnostically associated with OA based on JSW but only KL-score and pain in a non-linier fashion was prognostic. 50% of patients did not progress more than MSC, highlighting the importance for identification of structural progressors and the phenotypes associated with these. These results suggest that disease phenotypes, rather than disease status, are responsible for disease progression.

Causes of metabolic syndrome and obesity-related co-morbidities Part 1: A composite unifying theory review of human-specific co-adaptations to brain energy consumption

One line summary

Metabolic syndrome and obesity-related co-morbidities are largely explained by co-adaptations to the energy use of the large human brain in the cortico-limbic-striatal and NRF2 systems.

The medical, research and general community is unable to effect significantly decreased rates of central obesity and related type II diabetes mellitus (TIIDM), cardiovascular disease (CVD) and cancer. All conditions seem to be linked by the concept of the metabolic syndrome (MetS), but the underlying causes are not known. MetS markers may have been mistaken for causes, thus many treatments are destined to be suboptimal.

The current paper aims to critique current paradigms, give explanations for their persistence, and to return to first principles in an attempt to determine and clarify likely causes of MetS and obesity related comorbidities. A wide literature has been mined, study concepts analysed and the basics of human evolution and new biochemistry reviewed. A plausible, multifaceted composite unifying theory is formulated.

The basis of the theory is that the proportionately large, energy-demanding human brain may have driven co-adaptive mechanisms to provide, or conserve, energy for the brain. A ‘dual system’ is proposed. 1) The enlarged, complex cortico-limbic-striatal system increases dietary energy by developing strong neural self-reward/motivation pathways for the acquisition of energy dense food, and (2) the nuclear factor-erythroid 2-related factor 2 (NRF2) cellular protection system amplifies antioxidant, antitoxicant and repair activity by employing plant chemicals, becoming highly energy efficient in humans.

The still-evolving, complex human cortico-limbic-striatal system generates strong behavioural drives for energy dense food procurement, including motivating agricultural technologies and social system development. Addiction to such foods, leading to neglect of nutritious but less appetizing ‘common or garden’ food, appears to have occurred. Insufficient consumption of food micronutrients prevents optimal human NRF2 function. Inefficient oxidation of excess energy forces central and non-adipose cells to store excess toxic lipid. Oxidative stress and metabolic inflammation, or metaflammation, allow susceptibility to infectious, degenerative atherosclerotic cardiovascular, autoimmune, neurodegenerative and dysplastic diseases.

Other relevant human-specific co-adaptations are examined, and encompass the unusual ability to store fat, certain vitamin pathways, the generalised but flexible intestine and microbiota, and slow development and longevity.

This theory has significant past and future corollaries, which are explored in a separate article by McGill, A-T, in Archives of Public Health, 72: 31.

Immunologic and mass-spectrometric estimates of SHBG concentrations in healthy women

OBJECTIVE

Sex-hormone binding globulin (SHBG) concentrations across the adult female lifespan are not well defined. To address this knowledge gap, SHBG was quantified by both immunological and criterion methods, viz, mass spectrometry (MS).

SETTING

Center for Translational Science Activities (CTSA).

PARTICIPANTS

Healthy nonpregnant women (N=120) ages 21 to 79 years.

OUTCOMES

SHBG, testosterone (T), estradiol (E2) and estrone (E1) each determined by MS. Uni- and multivariate regression of SHBG concentrations on age, body mass index (BMI), total and visceral abdominal fat (TAF, AVF), albumin, glucose, insulin, sex steroids, selected cytokines, blood pressure, and lipids.

RESULTS

By univariate regression, MS-estimated SHBG correlated negatively with BMI, TAF, AVF, insulin, free T and bioavailable T (bio T) (each P≤10(-4)), but not with blood pressure or lipids. By stepwise multivariate regression analysis, free and total T (both positive) and bio T (negative) were correlated with SHBG in all 4 assays (each P<10(-15), R(2)≥0.481). In addition, TAF and BMI were negatively associated with SHBG (P≤0.0066) in 2 SHBG assays, and estrone and IL-8 with SHBG weakly (P≤0.035) in one SHBG assay each. When nonsignificant cytokines were excluded, SHBG was jointly associated with AVF, total T and HDL (P<10(-9), R(2)=0.358).

CONCLUSION

According to MS, three metabolic factors, T, AVF and HDL, together explain more than one-third of the interindividual variation in SHBG levels. We speculate that these measures reflect insulin action.

The metabolic effects of growth hormone in adipose tissue

There is a general consensus that a reduction in growth hormone (GH) secretion results in obesity. However, the pathophysiologic role of GH in the metabolism of lipids is yet to be fully understood. The major somatic targets of GH are bones and muscles, but GH stimulates lipolysis and seems to regulate lipid deposition in adipose tissue. Patients with isolated GH deficiency (GHD) have enlarged fat depots due to higher fat cell volume, but their fat cell numbers are lower than those of matched controls. The treatment of patients with GH results in a relative loss of body fat and shifts both fat cell number and fat cell volume toward normal, indicating an adipogenic effect of GH. Adults with GHD are characterized by perturbations in body composition, lipid metabolism, cardiovascular risk profile, and bone mineral density. It is well established that GHD is usually accompanied by an increase in fat accumulation; GH replacement in GHD results in the reduction of fat mass, particularly abdominal fat mass. In addition, abdominal obesity results in a secondary reduction in GH secretion that is reversible with weight loss. However, whereas GH replacement in patients with GHD leads to specific depletion of intra-abdominal fat, administering GH to obese individuals does not seem to result in a consistent reduction or redistribution of body fat. Although administering GH to obese non-GHD subjects has only led to equivocal results, more recent studies indicate that GH still remains a plausible metabolic candidate.

Prevalence rate of Metabolic Syndrome in a group of light and heavy smokers

BACKGROUND

Smoking is an important cause of morbidity and mortality worldwide. It is widely accepted as a major risk factor for metabolic and cardiovascular disease. Smoking reduces insulin sensitivity or induces insulin resistance and enhances cardiovascular risk factors such as elevated plasma triglycerides, decreases high-density lipoprotein cholesterol and causes hyperglycemia. Several studies show that smoking is associated with metabolic abnormalities and increases the risk of Metabolic Syndrome. The aim of this study was to estimate the prevalence of the metabolic syndrome in a group of light and heavy smokers, wishing to give up smoking.

METHODS

In this cross-sectional study all the enrolled subjects voluntary joined the smoking cessation program held by the Respiratory Pathophysiology Unit of San Matteo Hospital, Pavia, Northern Italy.All the subjects enrolled were former smokers from at least 10 years and had no cancer or psychiatric disorders, nor history of diabetes or CVD or coronary artery disease and were not on any medication.

RESULTS

The subjects smoke 32.3 ± 16.5 mean Pack Years. The prevalence of the metabolic syndrome is 52.1%: 57.3% and 44.9% for males and females respectively. Analysing the smoking habit influence on the IDF criteria for the metabolic syndrome diagnosis we found that all the variables show an increasing trend from light to heavy smokers, except for HDL cholesterol. A statistical significant correlation among Pack Years and waist circumference (R = 0.48, p < 0.0001), Systolic Blood Pressure (R = 0.18, p < 0.05), fasting plasma glucose (R = 0.19, p < 0.005) and HDL cholesterol (R = -0.26, p = 0.0005) has been observed.

CONCLUSIONS

Currently smoking subjects are at high risk of developing the metabolic syndrome.Therapeutic lifestyle changes, including smoking cessation are a desirable Public health goal and should successfully be implemented in clinical practice at any age.

Predicting total, abdominal, visceral and hepatic adiposity with circulating biomarkers in Caucasian and Japanese American women

Background

Characterization of abdominal and intra-abdominal fat requires imaging, and thus is not feasible in large epidemiologic studies.

Objective

We investigated whether biomarkers may complement anthropometry (body mass index [BMI], waist circumference [WC], and waist-hip ratio [WHR]) in predicting the size of the body fat compartments by analyzing blood biomarkers, including adipocytokines, insulin resistance markers, sex steroid hormones, lipids, liver enzymes and gastro-neuropeptides.

Methods

Fasting levels of 58 blood markers were analyzed in 60 healthy, Caucasian or Japanese American postmenopausal women who underwent anthropometric measurements, dual energy X-ray absorptiometry (DXA), and abdominal magnetic resonance imaging. Total, abdominal, visceral and hepatic adiposity were predicted based on anthropometry and the biomarkers using Random Forest models.

Results

Total body fat was well predicted by anthropometry alone (R² = 0.85), by the 5 best predictors from the biomarker model alone (leptin, leptin-adiponectin ratio [LAR], free estradiol, plasminogen activator inhibitor-1 [PAI1], alanine transaminase [ALT]; R² = 0.69), or by combining these 5 biomarkers with anthropometry (R² = 0.91). Abdominal adiposity (DXA trunk-to-periphery fat ratio) was better predicted by combining the two types of predictors (R² = 0.58) than by anthropometry alone (R² = 0.53) or the 5 best biomarkers alone (25(OH)-vitamin D₃, insulin-like growth factor binding protein-1 [IGFBP1], uric acid, soluble leptin receptor [sLEPR], Coenzyme Q10; R² = 0.35). Similarly, visceral fat was slightly better predicted by combining the predictors (R² = 0.68) than by anthropometry alone (R² = 0.65) or the 5 best biomarker predictors alone (leptin, C-reactive protein [CRP], LAR, lycopene, vitamin D₃; R² = 0.58). Percent liver fat was predicted better by the 5 best biomarker predictors (insulin, sex hormone binding globulin [SHBG], LAR, alpha-tocopherol, PAI1; R² = 0.42) or by combining the predictors (R² = 0.44) than by anthropometry alone (R² = 0.29).

Conclusion

The predictive ability of anthropometry for body fat distribution may be enhanced by measuring a small number of biomarkers. Studies to replicate these data in men and other ethnic groups are warranted.

Abdominal aortic calcification quantified by the Morphological Atherosclerotic Calcification Distribution (MACD) index is associated with features of the metabolic syndrome

Background

Abdominal aortic calcifications (AAC) predict cardiovascular mortality. A new scoring model for AAC, the Morphological Atherosclerotic Calcification Distribution (MACD) index may contribute with additional information to the commonly used Aortic Calcification Severity (AC24) score, when predicting death from cardiovascular disease (CVD). In this study we investigated associations of MACD and AC24 with traditional metabolic-syndrome associated risk factors at baseline and after 8.3 years follow-up, to identify biological parameters that may account for the differential performance of these indices.

Methods

Three hundred and eight healthy women aged 48 to 76 years, were followed for 8.3 ± 0.3 years. AAC was quantified using lumbar radiographs. Baseline data included age, weight, blood pressure, blood lipids, and glucose levels. Pearson correlation coefficients were used to test for relationships.

Results

At baseline and across all patients, MACD correlated with blood glucose (r² = 0.1, P< 0.001) and to a lesser, but significant extent with traditional risk factors (p < 0.01) of CVD. In the longitudinal analysis of correlations between baseline biological parameters and the follow-up calcification assessment using radiographs we found LDL-cholesterol, HDL/LDL, and the ApoB/ApoA ratio significantly associated with the MACD (P< 0.01). In a subset of patients presenting with calcification at both baseline and at follow-up, all cholesterol levels were significantly associated with the MACD (P< 0.01) index. AC24 index was not correlated with blood parameters.

Conclusion

Patterns of calcification identified by the MACD, but not the AC24 index, appear to contain useful biological information perhaps explaining part of the improved identification of risk of cardiovascular death of the MACD index. Correlations of MACD but not the AC24 with glucose levels at baseline suggest that hyperglycemia may contribute to unique patterns of calcification indicated by the MACD.

Hip circumference is associated with high density lipoprotein cholesterol response following statin therapy in hypertensive subjects

AIM

This report investigated the relationship between anthropometric measurements of body fat distribution and lipid response to statins in hypercholesterolemic hypertensive patients.

METHODS

We prospectively examined 129 subjects who used either simvastatin 20 mg/day (no.=83) or atorvastatin 10 mg/day (no.=46) for 3 months. Anthropometry included evaluation of body mass index, waist and hip circumferences, and waist-to-hip-ratio.

RESULTS

Significant decreases in LDL (p<0.001), total cholesterol (p<0.001), and triglycerides (p=0.04) levels were detected after 3 months of therapy in the whole sample. At baseline, only an inverse correlation between waist circumference and HDLcholesterol levels was detected (r=-0.18; p=0.04). Conversely, a direct relationship between hip circumference and HDLcholesterol response to statins was found in the whole sample (r=0.24; p=0.006), while no other anthropometric measurement displayed significant correlation with lipid changes. The association between HDL-cholesterol response and hip circumference was further confirmed by stepwise regression analysis adjusted for baseline HDL-cholesterol levels, metabolic syndrome, body mass index, and waist circumference.

CONCLUSIONS

Hip circumference, a surrogate marker of peripheral adiposity, is associated with HDL-cholesterol changes following statin therapy in hypertensive patients.

Low serum levels of total and high-molecular-weight adiponectin predict the development of metabolic syndrome in Japanese-Americans

BACKGROUND

Adiponectin is thought to play a significant role in the development of both insulin resistance and metabolic syndrome. Yet, there is very few evidence about the association plasma adiponectin and metabolic syndrome in the prospective study. Adiponectin exists as multimers in serum, and high-molecular-weight (HMW) adiponectin is particularly considered to be the active form of the protein.

AIM

We investigated whether serum HMW adiponectin as well as total adiponectin is associated with the development of metabolic syndrome in a longitudinal study.

SUBJECTS AND METHODS

We enrolled 224 men and 312 women of Japanese- Americans without metabolic syndrome at baseline who were followed for an average of 3.2 yr. The association of plasma total and HMW adiponectin with a progression to metabolic syndrome was examined.

RESULTS

Subjects who developed metabolic syndrome had significantly lower plasma total and HMW adiponectin levels at baseline than those who did not develop metabolic syndrome. In a Cox proportional hazards model, lower total and HMW adiponectin levels were independent risk factors for the development of metabolic syndrome after adjusting for age, body mass index, classification of 75-g glucose tolerance test, and homeostasis model assessment (hazards ratio: total, 0.684, p=0.017, in men; 0.606, p=0.003, in women; HMW, 0.687, p=0.014, in men; 0.704, p=0.029, in women, respectively).

CONCLUSIONS

Low circulating levels of total and HMW adiponectin may be a possible predictor for the development of metabolic syndrome.

Evaluation of anthropometric indices for metabolic syndrome in Chinese adults aged 40 years and over

BACKGROUND

The prevalence of metabolic syndrome (MetS) is increasing worldwide with a marked impact in cardiovascular disease (CVD) and diabetes risk.

AIM OF THE STUDY

To evaluate the anthropometric indices for metabolic syndrome (MetS) and determine the optimal cut-off values of waist circumference (WC), body mass index (BMI), and waist height ratio (WHtR) for MetS in Chinese adults aged 40 years and over.

METHODS

A sample of Chinese adults aged 40 years and over including 430 men and 638 women was investigated. Blood pressure, weight, height, and WC were measured; HDL-cholesterol (HDL-C), Triglyceride (TG), and plasma glucose were examined. Receiver operating characteristics (ROC) curve analyses were used to evaluate the optimal cut-off point of WC, BMI, and WHtR for MetS.

RESULTS

According to the ROC curve analysis, the optimal cut-off point for WC was found to be 84.0 cm in men and 80.0 cm in women; for BMI, it was 26.0 in men and 25.0 in women; and for WHtR, it was 0.5 in both men and women. WHtR has the highest predictive value for fast plasma glucose in women, while BMI has the better prediction of dyslipidemia in men.

CONCLUSIONS

Anthropometric indices (WC, BMI, and WHtR) are useful screening tools for obesity, MetS, and CVD risk factors. BMI may be a better indicator than the others for screening obesity, dyslipidemia, and other risk components in Chinese men aged 40 years and over, while WHtR may be better for Chinese women, especially among those aged 70 years and over.

The impact of race/ethnicity on baseline characteristics and the burden of coronary atherosclerosis in the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial

OBJECTIVES

We aimed to test the impact of race/ethnicity on coronary artery disease (CAD) after adjusting for baseline risk factors.

BACKGROUND

Whether race/ethnicity remains an important determinant of the burden of CAD even among patients with long-standing type 2 diabetes (diabetes mellitus) and established CAD is unknown.

METHODS

Analysis of baseline data from the BARI 2D trial (January 1, 2001, to March 31, 2005) was performed. Myocardial jeopardy index (MJI) was evaluated by a blinded core angiographic laboratory. Multivariate regression analysis was performed to determine the independent association of race/ethnicity on the burden of CAD after adjusting for baseline risk factors. Data were collected from US and Canadian academic and community hospitals. The baseline analysis was performed on patients with long-standing diabetes and documented CAD with no prior revascularization at study entry (n = 1,331). The main outcome measure was MJI, which represents the percentage of myocardium jeopardized by significant lesions (≥50%). The secondary outcome measure was ≥2 lesions with ≥50% stenosis.

RESULTS

Risk factors varied significantly among racial/ethnic groups. Blacks were significantly more likely to be women, have no health insurance, be current smokers, have higher body mass index, have hypertension, have a longer duration of diabetes, a higher hemoglobin A(1c) level, and were more likely to be taking insulin. Their mean total, low-density lipid, and high-density lipid cholesterol levels were higher, whereas their triglycerides were lower than others. After controlling for baseline risk factors, blacks had a significantly lower burden of CAD; the adjusted MJI was 5.43 U lower (95% CI -9.13 to -1.72), and the adjusted number of lesions was 0.53 fewer (95% CI -0.88 to -0.18) in blacks compared to whites.

CONCLUSIONS

In the BARI 2D trial, self-reported race/ethnicity is associated with important differences in baseline risk factors and is a powerful predictor of the burden of CAD adjusting for such baseline differences. These findings may help direct medical intervention and resources and further investigation into the basis of racial/ethnic differences in CAD burden.

Effects of ovariectomy and estrogen replacement therapy on visceral adipose tissue and serum adiponectin levels in rats

BACKGROUND

Excess visceral adipose tissue accumulation after menopause is closely associated with decreased insulin sensitivity and adiponectin levels.

OBJECTIVE

The purpose of this study was to determine the effect of ovariectomy and estrogen replacement on visceral fat and serum adiponectin levels in ovariectomized (OVX) rats.

METHOD

Forty 11-week-old female Wistar rats were divided into the four following groups (n = 10 rats per group): sham-operated control (SHAM); sedentary OVX (OVX-SED); OVX with estrogen replacement (OVX-ER); and OVX with sesame oil treatment (OVX-C). Rats in OVX-ER and OVX-C groups received 17β-estradiol valerate (30 µg/kg, subcutaneously) and sesame oil as vehicle, five days a week, respectively. All animals were sacrificed after eight weeks of intervention.

RESULTS

Ovariectomy after eight weeks increased body weight and visceral fat (P < 0.05) in OVX-SED and OVX-C groups compared with SHAM rats with no change in plasma adiponectin levels. Estrogen replacement in OVX animals decreased body weight (13.4%, P < 0.05) and visceral fat (10.4%). Although they were not statistically significant, adiponectin, insulin sensitivity and lipid profile of OVX rats were ameliorated with estrogen treatment.

CONCLUSION

We conclude that ovarian hormone withdrawal leads to higher body weight and visceral adipose tissue in rats, but surprisingly does not change adiponectin levels. Although a substantial decrease in body weight was achieved by estrogen replacement therapy in OVX animals, the beneficial metabolic effects of weight loss seems to be only mechanical, having a tendency to improve insulin sensitivity without elevating adiponectin production.

Serum adiponectin is associated with homocysteine in elderly men and women, and with 5,10-methylenetetrahydrofolate reductase (MTHFR) in a sex-dependent manner

Plasma homocysteine associates positively with cardiovascular disease. C-to-T substitution at base 677 of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene associates with increased plasma homocysteine. The association of adiponectin with cardiovascular disease is unclear. This study of survivors of a 30-year cohort of the Jewish Israeli population, 310 men and 273 women (mean age, 70.5 ± 7.0 years for both), investigated the relationship between adiponectin and homocysteine, and between adiponectin and the MTHFR C677T genotype. Serum adiponectin associated positively with total homocysteine in both men (r = 0.27, P < .001) and women (r = 0.22, P < .001). In women, the TT MTHFR genotype associated with lower median adiponectin levels, 8.98 mg/L, compared with 9.88 and 10.57 mg/L for TC and CC, respectively (P = .05; CC vs TT, P = .01). In men, the trend was opposite, but not statistically significant: 7.90, 7.03, and 6.88 mg/L for TT, TC, and CC genotypes, respectively (P = .5). This study demonstrated a positive association between homocysteine and adiponectin in both elderly men and women and a statistically significant association between adiponectin and MTHFR C677T genotypes in women only.

Biochemical markers identify influences on bone and cartilage degradation in osteoarthritis--the effect of sex, Kellgren-Lawrence (KL) score, body mass index (BMI), oral salmon calcitonin (sCT) treatment and diurnal variation

Background

Osteoarthritis (OA) involves changes in both bone and cartilage. These processes might be associated under some circumstances. This study investigated correlations between bone and cartilage degradation in patients with OA as a function of sex, Kellgren-Lawrence (KL) score, Body Mass Index (BMI), oral salmon calcitonin (sCT) treatment and diurnal variation.

Methods

This study was a 2-week, double-blind, double-dummy, randomized study including 37 postmenopausal women and 36 men, aged 57-75 years, with painful knee OA, and a KL-score of I - III. Subjects were allocated to one of three treatment arms: 0.6 mg or 0.8 mg oral sCT, or placebo given twice-daily for 14 days. Correlations between gender, KL score, or BMI and the bone resorption marker, serum C-terminal telopeptide of collagen type I (CTX-I), or the cartilage degradation marker, urine C-terminal telopeptide of collagen type II (CTX-II) were investigated.

Results

At baseline, biomarkers indicated women with OA experienced higher bone and cartilage degradation than men. CTX-I levels were significantly higher, and CTX-II levels only marginally higher, in women than in men (p = 0.04 and p = 0.06, respectively). Increasing KL score was not correlated with bone resorption, but was significantly associated with the cartilage degradation CTX-II marker in both men and women (p = 0.007). BMI was significantly and negatively correlated to the bone resorption marker CTX-I, r = -0.40 (p = 0.002), but showed only a borderline positive correlation to CTX-II, r = 0.25 (p = 0.12). Before morning treatments on days 1 and 14, no correlation was seen between CTX-I and CTX-II in either the sCT or placebo group. However, oral sCT and food intake induced a clear correlation between these bone and cartilage degradation markers. Four hours after the first sCT dose on treatment days 1 and 14, a significant correlation (r = 0.71, p < 0.001) between changes in both CTX-I and CTX-II was seen. In the placebo group a weakly significant correlation between changes in both markers was found on day 1 (r = 0.49, p = 0.02), but not on day 14.

Conclusion

Bone resorption was higher in females than males, while cartilage degradation was correlated with increasing KL-score and only weakly associated with BMI. Bone and cartilage degradation were not correlated in untreated individuals, but dosing with oral sCT with or without food, and a mid-day meal, decreased bone and cartilage degradation and induced a correlation between both markers. Changes in bone and cartilage markers may aid in the identification of potential new treatment opportunities for OA.

Trial Registration

Clinical trial registration number (EUDRACT2006-005532-24 & NCT00486369)

Adiponectin is related to intramyocellular lipid content in non-diabetic adults

OBJECTIVE

Insulin resistance (IR) is associated with intramyocellular lipid (IMCL) content and low serum adiponectin (ADP) levels and ADP is also involved in muscle fat oxidation. However, the relationship between ADP and IMCL content is still controversial and in this study we explored it further in non-diabetic adults.

DESIGN

Cross-sectional clinical study.

SUBJECTS

Thirty-three adult subjects, 24 obese non-diabetic patients with metabolic syndrome (MS) and 9 lean healthy controls.

MEASUREMENTS

Proton nuclear magnetic resonance spectroscopy (1H-NMRS) was performed to quantify IMCL content. The latter plus serum ADP, anthropometrics and biochemical parameters were evaluated and compared in these 2 groups.

RESULTS

MS patients had higher body mass index, waist, waist-to- hip ratio, glucose, insulin, and triglycerides and lower HDL cholesterol (HDLc) compared to controls. Homeostasis model assessment of IR (HOMA-IR) [3.25 (2.58-4.13) vs 1.02 (0.73- 1.29); p<0.0001] and IMCL content [266.1 (189.9-296.3) vs 72.85 (55.3-109.4) AU, p<0.0001] were higher, and quantitative insulin-sensitivity check index (QUICKI) [0.32 (0.31-0.33) vs 0.38 (0.37-0.40); p<0.0001] and ADP [8.6 (4.05-15.95) vs 21.1 (12.9- 24.4) microg/ml; p=0.02] were lower in MS subjects compared to controls. IMCL content was directly associated to glucose, insulin, triglycerides, and HOMA-IR and inversely to HDLc, QUICKI and, more importantly, to ADP (r=-0.41; p<0.05). Only in the MS group, ADP partially influenced IMCL content.

CONCLUSION

ADP is inversely related to IMCL content in non-diabetic adults. This finding has possible implications for the role of ADP in muscle fat oxidation, IR, and MS.

Human macrophage foam cells degrade atherosclerotic plaques through cathepsin K mediated processes

Background

Proteolytic degradation of Type I Collagen by proteases may play an important role in remodeling of atherosclerotic plaques, contributing to increased risk of plaque rupture.

The aim of the current study was to investigate whether human macrophage foam cells degrade the extracellular matrix (ECM) of atherosclerotic plaques by cathepsin K mediated processes.

Methods

We 1) cultured human macrophages on ECM and measured cathepsin K generated fragments of type I collagen (C-terminal fragments of Type I collagen (CTX-I) 2) investigated the presence of CTX-I in human coronary arteries and 3) finally investigated the clinical potential by measuring circulating CTX-I in women with and without radiographic evidence of aortic calcified atherosclerosis.

Results

Immune-histochemistry of early and advanced lesions of coronary arteries demonstrated co-localization of Cathepsin-K and CTX-I in areas of intimal hyperplasia and in shoulder regions of advanced plaques. Treatment of human monocytes with M-CSF or M-CSF+LDL generated macrophages and foam cells producing CTX-I when cultured on type I collagen enriched matrix. Circulating levels of CTX-I were not significantly different in women with aortic calcifications compared to those without.

Conclusions

Human macrophage foam cells degrade the atherosclerotic plaques though cathepsin K mediated processes, resulting in increase in levels of CTX-I. Serum CTX-I was not elevated in women with aortic calcification, likely due to the contribution of CTX-I from osteoclastic bone resorption which involves Cathepsin-K. The human macrophage model system may be used to identify important pathway leading to excessive proteolytic plaque remodeling and plaque rupture.

Obesity, growth hormone and weight loss

Growth hormone (GH) is the most important hormonal regulator of postnatal longitudinal growth in man. In adults GH is no longer needed for longitudinal growth. Adults with growth hormone deficiency (GHD) are characterised by perturbations in body composition, lipid metabolism, cardiovascular risk profile and bone mineral density. It is well established that adult GHD usually is accompanied by an increase in fat accumulation and GH replacement in adult patients with GHD results in reduction of fat mass and abdominal fat mass in particular. It is also recognized that obesity and abdominal obesity in particular results in a secondary reduction in GH secretion and subnormal insulin-like growth factor-I (IGF-I) levels. The recovery of the GH IGF-I axis after weight loss suggest an acquired defect, however, the pathophysiologic role of GH in obesity is yet to be fully understood. In clinical studies examining the efficacy of GH in obese subjects very little or no effect are observed with respect to weight loss, whereas GH seems to reduce total and abdominal fat mass in obese subjects. The observed reductions in abdominal fat mass are modest and similar to what can be achieved by diet or exercise interventions.

Central-to-peripheral fat ratio, but not peripheral body fat, is related to insulin resistance and androgen markers in polycystic ovary syndrome

BACKGROUND

Overweight, hyperandrogenism and insulin resistance are cardinal features of patients with polycystic ovary syndrome (PCOS). Women with PCOS have excess accumulation of trunkal fat and metabolic complications. Recent findings suggest that peripheral fat may have metabolic protective behaviour. The aim of this study was to investigate body fat distribution in patients with PCOS and associations of peripheral fat with metabolic and hormonal profile.

METHODS

The study included 24 patients with PCOS and a control group of 13 women. Anthropometrical evaluation and dual-energy X-ray absorptiometry to determine body composition was performed. Plasma metabolic and hormonal profiles were evaluated.

RESULTS

Patients with PCOS have increased proportion of central to peripheral fat ratio (CPFR) when compared to controls (p = 0.008). There was a positive correlation among trunkal fat, insulin, HOMA-IR and triglycerides (all p < 0.05). Regarding to peripheral fat there was no difference between groups, a trend to negative correlation to insulin appeared. Positive correlation between free androgens index and CPFR (p = 0.058) and a negative correlation between SHBG and CPFR (p = 0.016) were appeared.

CONCLUSIONS

Patients with PCOS showed an android pattern fat distribution when compared to controls. Peripheral fat contribution and its relations to androgens in this context could not be established. Android pattern of fat distribution showed inverse correlation to SHBG levels, suggesting that SHBG may be related to fat distribution.

Thigh circumference and risk of heart disease and premature death: prospective cohort study

OBJECTIVE

To examine associations between thigh circumference and incident cardiovascular disease and coronary heart disease and total mortality.

DESIGN

Prospective observational cohort study with Cox proportional hazards model and restricted cubic splines.

SETTING

Random subset of adults in Denmark.

PARTICIPANTS

1436 men and 1380 women participating in the Danish MONICA project, examined in 1987-8 for height, weight, and thigh, hip, and waist circumference, and body composition by impedance.

MAIN OUTCOME MEASURES

10 year incidence of cardiovascular and coronary heart disease and 12.5 years of follow-up for total death.

RESULTS

A small thigh circumference was associated with an increased risk of cardiovascular and coronary heart diseases and total mortality in both men and women. A threshold effect for thigh circumference was evident, with greatly increased risk of premature death below around 60 cm. Above the threshold there seemed to be no additional benefit of having larger thighs in either sex. These findings were independent of abdominal and general obesity, lifestyle, and cardiovascular risk factors such as blood pressure and lipid concentration.

CONCLUSION

A low thigh circumference seems to be associated with an increased risk of developing heart disease or premature death. The adverse effects of small thighs might be related to too little muscle mass in the region. The measure of thigh circumference might be a relevant anthropometric measure to help general practitioners in early identification of individuals at an increased risk of premature morbidity and mortality.

Effects of drospirenone/estrogen combinations on bone metabolism

Bone mass is maintained when low-dose ethinylestradiol is used in combination with the new progestogen drospirenone as an oral contraceptive, making a regimen of drospirenone combined with 17beta-estradiol an attractive option for hormone replacement therapy (HRT) in postmenopausal women. Drospirenone is a novel progestogen, more closely related to endogenous progesterone in its pharmacological properties than other progestogens available; in combination with estrogen, drospirenone can closely mimic the premenopausal hormonal balance. In a phase II/III double-blind, placebo-controlled, randomized trial, three different doses of drospirenone plus low-dose 17beta-estradiol were compared with placebo, in order to determine their effects on bone density. Of 240 healthy postmenopausal women aged 45-65 years who enrolled, 180 completed the 2-year prospective study. Treatment groups received 1 mg 17beta-estradiol combined with 1, 2 or 3 mg drospirenone daily or placebo. Bone mineral densities at the lumbar spine, hip and total body and markers of bone turnover were measured at 1, 3, 6, 12, 18 and 24 months. In the pooled HRT groups, the bone mineral density at the lumbar spine, hip and total body increased by 7%, 4% and 3%, respectively, compared with placebo (all p < 0.001). Markers of bone turnover in HRT groups all decreased accordingly (serum osteocalcin 52%, serum bone-specific alkaline phosphatase 36%, serum CrossLaps 67% and urinary CrossLaps 75% from baseline; all p < 0.001). The combination of 17beta-estradiol with drospirenone offers a safe and effective medication for decreasing bone turnover and preventing postmenopausal bone loss in postmenopausal women.

Comparable reduction of the visceral adipose tissue depot after a diet-induced weight loss with or without aerobic exercise in obese subjects: a 12-week randomized intervention study

OBJECTIVE

Weight loss with preferential effect on the visceral adipose tissue (VAT) depot could have important clinical benefits. In this study, we investigated the independent and combined effect of regular exercise and diet induced weight loss on body fat distribution. DESIGN; Randomized control design of i) exercise-only (EXO; 12 weeks of exercise without diet-restriction), ii) hypocaloric-diet (DIO; 8 weeks of very low energy diet (VLED 600 kcal/day) followed by 4-weeks weight maintenance diet) and iii) hypocaloric-diet and exercise (DEX; 8 weeks VLED 800 kcal/day+a 4-week weight maintenance diet combined with exercise throughout the 12 weeks).

SUBJECTS

Seventy-nine obese males and females were included.

MEASUREMENTS

Body fat distribution was quantified by magnetic resonance imaging (MRI)-technology.

RESULTS

In the EXO group, the weight loss (3.5 kg) and the relative reduction in VAT (18%) was significantly lower compared with the weight losses in the DIO and DEX groups (12.3 kg; P<0.01) and to the reduction in VAT (30-37%; P<0.01). In all the three groups, the relative reduction of VAT was higher as compared with the reduction in fat mass (FM; combining all fat depots determined by MRI; P<0.01 for all comparisons). The changes in VAT were associated with changes in FM and related to the initial VAT/FM ratio (r(2)=0.72; P<0.01).

CONCLUSION

Exercise has no additional effects in reduction of the VAT depot, compared with the major effects of hypocaloric diet alone. In addition, the effects of exercise per se on VAT are relatively limited. The effects on the VAT depot are closely associated with changes in total FM.

Relationship of adiposity with arterial stiffness as mediated by adiponectin in older men and women: the Hoorn Study

OBJECTIVE

To investigate whether adiponectin is associated with arterial stiffness, and whether adiponectin explains the association between body composition and arterial stiffness.

DESIGN

Cross-sectional cohort study.

METHODS

Subjects were participants (n=456, mean age 68.9+/-6.1 years; age range 60-86 years) of the third follow-up examination of the Hoorn Study. Trunk fat, leg fat, trunk lean, and leg lean mass were measured by dual-energy X-ray absorptiometry. Ultrasound was used to measure distensibility and compliance of the carotid, femoral, and brachial arteries, and carotid Young's elastic modulus (as estimates of peripheral arterial stiffness). Results Trunk fat mass was negatively associated with (ln-transformed) adiponectin (standardized beta=-0.49, P<0.001), while leg fat mass was positively associated with adiponectin (beta=0.44, P<0.001), after adjustment for each other, age, and lean mass. After adjustment for age, sex, mean arterial pressure, and estimated glomerular filtration rate, higher adiponectin was associated with decreased peripheral arterial stiffness (beta of mean Z-scores of all three arteries=0.14, P=0.001). However, the associations of trunk fat (beta=-0.26, P<0.001) and leg fat (beta=0.16, P=0.006) with peripheral arterial stiffness were only minimally explained by adiponectin levels.

CONCLUSION

Trunk fat and leg fat are oppositely associated with adiponectin. Although low adiponectin was a determinant of increased peripheral arterial stiffness, it only explained a small part of the association between body fat and peripheral arterial stiffness. This indicated that factors other than adiponectin may be more important in the pathophysiological mechanisms by which abdominal obesity leads to arterial stiffness.

Obesity and inflammation: lessons from bariatric surgery

BACKGROUND

Obesity is associated with a series of comorbid conditions that are characterized by an inflammatory state. The purpose of this review is to update knowledge about obesity, adipose tissue, and inflammation.

METHODS

Review of the published literature using search terms of adipose, inflammation, obesity, and insulin resistance in combinations.

RESULTS

Adipose tissue elaborates proinflammatory cytokines such as interleukin-6 and tumor necrosis factor-alpha, with greater secretion from the stromal vascular fraction than from adipocytes and with greater secretion from visceral than subcutaneous adipose tissue sites. This proinflammatory state is associated with insulin resistance and ameliorated by weight loss, with concurrent increase in production of the anti-inflammatory adipokine adiponectin.

CONCLUSION

Although these associations between obesity and inflammation are clearly important, many questions remain unresolved. It is unclear if benefits of weight loss pertain only to those with a proinflammatory profile, who receive a particular type of obesity surgical procedure, or whether these benefits are sustained over a lifetime. The outcomes associated with anti-inflammatory nutrient supplementation, with or without weight loss, in the obese would also increase our understanding.

Role of estrogen receptor-alpha and -beta in regulating leptin expression in 3T3-L1 adipocytes

We investigated the effects of the estrogen receptor-alpha (ERalpha) and -beta (ERbeta) in the regulation of leptin, resistin, and adiponectin expression in 3T3-L1 adipocytes. Mature adipocytes were exposed to estradiol (E2), ERalpha agonist (PPT (4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol)), ERbeta agonist (DPN (2,3-bis(4-Hydroxyphenyl)-propionitrile)), E2 with ERalpha antagonist (MPP (1,3-Bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1H-pyrazole dihydrochloride)), and E2 with ERbeta antagonist (R,R-THC ((R,R)-5,11-diethyl-5,6,11,12-tetrahydro-2,8-chrysenediol)) at different concentrations. To clarify the expression and regulation of adipokines by ER subtypes, total RNA was extracted from cells and measured using quantitative PCR. Western blot analysis was performed to evaluate the protein expression of adipokines, ERalpha, and ERbeta. The leptin expression was significantly increased in the cells treated with high concentrations (10(-5) and 10(-6) mol/l) of the PPT (P < 0.01, P < 0.05). By contrast, the leptin expression decreased in a dose-dependent manner in the MPP-treated groups (P < 0.05). High concentrations (10(-5) mol/l) of R,R-THC with E2 (10(-7) mol/l) caused a significant increase of the leptin expression (P < 0.01). The leptin mRNA levels were positively correlated with the ERalpha mRNA levels (r = 0.584, P < 0.01) and negatively correlated with the ERbeta mRNA levels (r = -0.236, P = 0.03) in the adipocytes. The ratio of the ERalpha to ERbeta mRNA levels in the adipocytes was significantly associated with leptin mRNA levels (r = 0.454, P < 0.01). ERalpha induced leptin expression and ERbeta inhibited its expression in 3T3-L1 adipocytes. The ratio of the ERalpha-to-ERbeta expression in 3T3-L1 adipocytes may be an important potential regulatory factor in leptin expression.

Independent and opposite associations of hip and waist circumference with metabolic syndrome components and with inflammatory and atherothrombotic risk factors in overweight and obese women

Recent studies have shown independent and opposite associations of hip circumference (HC) and waist circumference (WC) with glucose intolerance, insulin resistance, and type 2 diabetes mellitus. However, no studies have simultaneously considered the independent contributions of both markers to metabolic proinflammatory and atherosclerotic risk factors. In this study, we examine the independent associations of WC and HC with metabolic syndrome and with proinflammatory and atherothrombotic features. Independent associations of thigh muscle and adipose tissue (AT) compartments with metabolic features were also studied. Abdominal and thigh muscle and AT distributions were assessed by computed tomography in 140 overweight and obese women (mean +/- SD: age, 38.3 +/- 0.5 years; body mass index, 30.4 +/- 0.3 kg/m(2)). Blood lipids and inflammatory and atherothrombotic markers were measured. For a given WC, a larger HC was inversely associated with fasting insulin (beta = -0.288, P = .008), hemoglobin A(1c) (beta = -0.246, P = .041), and plasminogen activator inhibitor-1 concentrations (beta = -0.241, P = .023). Contrarily, WC was related with an unfavorable metabolic profile. For a given WC, higher total thigh AT and total thigh subcutaneous AT masses were associated with lower hemoglobin A(1c) (beta = -0.244, P = .049; beta = -0.233, P = .049) and low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (beta = -0.252, P = .040; beta = -0.245, P = .037). In addition, total thigh AT was related with leptin (beta = 0.310, P = .012), whereas total thigh subcutaneous AT revealed opposite associations with fasting insulin concentrations (beta = -0.239, P = .034). Total thigh muscular tissue mass was related with lower plasminogen activator inhibitor-1 (beta = -0.164, P = .049) and fibrinogen concentrations (beta = -0.222, P = .018). In conclusion, HC revealed independent and opposite associations with insulin resistance and atherothrombotic disturbances. Contrarily, a larger WC predicted an increased metabolic risk. These contrasting effects in diabetogenic and atherothrombotic disturbances were, respectively, mediated by gluteofemoral AT and thigh muscle tissue. Besides body mass index and WC screening relevance, HC can contribute to additionally predict health risk in overweight and obese women.

Adipose tissue dysfunction in obesity, diabetes, and vascular diseases

The classical perception of adipose tissue as a storage place of fatty acids has been replaced over the last years by the notion that adipose tissue has a central role in lipid and glucose metabolism and produces a large number of hormones and cytokines, e.g. tumour necrosis factor-alpha, interleukin-6, adiponectin, leptin, and plasminogen activator inhibitor-1. The increased prevalence of excessive visceral obesity and obesity-related cardiovascular risk factors is closely associated with the rising incidence of cardiovascular diseases and type 2 diabetes mellitus. This clustering of vascular risk factors in (visceral) obesity is often referred to as metabolic syndrome. The close relationship between an increased quantity of visceral fat, metabolic disturbances, including low-grade inflammation, and cardiovascular diseases and the unique anatomical relation to the hepatic portal circulation has led to an intense endeavour to unravel the specific endocrine functions of this visceral fat depot. The objective of this paper is to describe adipose tissue dysfunction, delineate the relation between adipose tissue dysfunction and obesity and to describe how adipose tissue dysfunction is involved in the development of diabetes mellitus type 2 and atherosclerotic vascular diseases. First, normal physiology of adipocytes and adipose tissue will be described.

Obesity and risk of pancreatic cancer among postmenopausal women: the Women's Health Initiative (United States)

A total of 138,503 women in the Women's Health Initiative in the United States were followed (for an average of 7.7 years) through 12 September 2005 to examine obesity, especially central obesity in relation to pancreatic cancer (n=251). Women in the highest quintile of waist-to-hip ratio had 70% (95% confidence interval 10-160%) excess risk of pancreatic cancer compared with women in the lowest quintile.

Reversal of metabolic syndrome characteristics

BACKGROUND

Metabolic syndrome (MetS) is a constellation of three or more clinical health abnormalities from a list of five and, therefore, can vary significantly in its profile. Successful intervention strategies for preventing or resolving individuals' MetS may benefit from better understanding how specific risk factor profiles influence improvement in syndrome status.

METHODS

A retrospective analysis of clinical records for members participating in a university-based health assessment/fitness center between 1978 and 2003 was undertaken in 2005. First-year and second-year measures of body mass index, triglycerides, high-density lipoproteins, fasting blood glucose, and blood pressure were compared. Prevalence of individual MetS risk markers, as well as deviation from cut-point levels, were compared in members with and without the syndrome and in subgroups of those whose MetS status changed between the two examinations.

RESULTS

Of the 878 members analyzed, 133 (15%) presented with metabolic syndrome at first visit. Within 2 years of participating in a health assessment/fitness center, 42% of the members resolved their MetS status. Elevated triglycerides differentially characterized those participants who did not improve their MetS status, since that risk marker was not prevalent in the reversal group, but was 86% prevalent in the nonreversal group. For those who resolved their MetS status, there was a 33% improvement in triglycerides level.

CONCLUSIONS

While MetS resolution was achieved within 2 years for many participants in this study, it is likely that customized treatment interventions are necessary for those individuals with elevated triglycerides, the chief abnormality for those who did not resolve.

Reduced high-molecular-weight adiponectin and elevated high-sensitivity C-reactive protein are synergistic risk factors for metabolic syndrome in a large-scale middle-aged to elderly population: the Shimanami Health Promoting Program Study

OBJECTIVE

In Western countries, one of the most important modifiable targets for the prevention of cardiovascular diseases is metabolic syndrome. Adiponectin is an adipose tissue-specific plasma protein that inversely associates with metabolic syndrome. Among several molecular isoforms, high-molecular-weight (HMW) complex is considered the active form. Increased serum high-sensitivity C-reactive protein (hsCRP) concentration also associates with metabolic syndrome, and adiponectin could modulate plasma C-reactive protein levels. Here, through cross-sectional investigation, we investigated whether reduced HMW adiponectin and increased hsCRP levels in plasma are synergistically associated with metabolic syndrome. Measurement of HMW complex of adiponectin is one of the novelties of this study.

DESIGN

We analyzed 1845 community-dwelling middle-aged to elderly subjects (62+/-13 yr). Plasma HMW adiponectin levels were measured by ELISA. Clinical parameters were obtained from the subjects' personal health records, evaluated at their annual medical check-up.

RESULTS

Each component of metabolic syndrome, except for raised blood pressure, showed significantly lower plasma HMW adiponectin concentrations for both men and women (P<0.001). In contrast, plasma hsCRP levels were significantly higher in subjects with metabolic disorders (P<0.001). After adjusting for other confounding factors, HMW adiponectin [log normalized, odds ratio 0.084 (95% confidence interval 0.050-0.142), P<0.001] and hsCRP [3.009 (2.175-4.163), P<0.001] were identified as independent determinants of metabolic syndrome. In addition to the direct associations, we also observed a synergistic effect between these two molecules (F=11.8, P<0.001).

CONCLUSIONS

Reduced HMW adiponectin and elevated hsCRP are synergistically associated with the accumulation of metabolic disorders. The combination of these markers would be useful for identifying at-risk populations.

Level of ex vivo interleukin 6 expression in human peripheral fat compared with other tissues

OBJECTIVES

Adipose tissue is able to secrete a variety of active mediators into the circulation. One of these is Interleukin 6 (IL6). IL6 may play a causal role in the development of atherosclerosis. It has therefore been suggested that IL6 may form part of the link between obesity and vascular disease. The aim of this study was to quantify the relative IL6 expression in adipose tissue compared to other tissues.

METHODS

Tissue (vein, fat, muscle, blood) was collected from 32 patients undergoing varicose vein surgery. RNA was extracted and mRNA measured using RT-PCR relative quantification. The mean relative IL6 mRNA levels were compared between tissues using the Mann Whitney U test and the independent t-test. Tissue levels were compared for individuals using the Wilcoxon signed rank test.

RESULTS

Mean relative IL6 mRNA levels (mean+/-SEM) were significantly greater in adipose tissue 44.8+/-16.1 than in other tissues (leukocytes 1.1+/-0.3, vein 2.0+/-0.8, muscle 0.06+/-0.03: p<0.001). mRNA expression levels were also significantly higher in fat than in all other tissue types in individuals (p<0.001).

CONCLUSIONS

IL6 mRNA expression is significantly higher in adipose than in many other tissues known to express IL6.

Serum total and high molecular weight adiponectin levels are correlated with the severity of diabetic retinopathy and nephropathy

OBJECTIVE

Adiponectin is secreted specifically from adipocytes, and improves insulin sensitivity. Of its isoforms, the high molecular weight (HMW) complex is thought to be the most active. The aim of this study was to determine the relationship between serum total or HMW adiponectin and diabetic microangiopathy.

DESIGN, PATIENTS AND MEASUREMENTS

We analysed 198 Japanese patients with type 2 diabetes mellitus (T2DM) whose fasting serum samples were available. Serum total adiponectin and HMW adiponectin were measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Serum total adiponectin was found to have increased in the advanced stages of diabetic retinopathy (mean +/- SE, none, 6.9 +/- 0.3; simple, 8.3 +/- 1.0; preproliferative, 8.4 +/- 0.8; proliferative, 12 +/- 1.1 mg/l; anovaP = 0.0004) and nephropathy (stage I, 7.0 +/- 0.3; II, 7.7 +/- 0.5; III, 9.5 +/- 0.9; IV, 16 +/- 4.5 mg/l, P < 0.0001). Similarly, serum HMW adiponectin had increased in the advanced stages of retinopathy (3.7 +/- 0.2, 4.6 +/- 0.5, 4.6 +/- 0.6 and 6.9 +/- 0.8 mg/l, respectively, P = 0.0005) and nephropathy (3.7 +/- 0.2, 4.3 +/- 0.4, 5.3 +/- 0.7 and 7.9 +/- 2.2 mg/l, respectively, P = 0.0007). Neither serum total nor HMW adiponectin was correlated with neuropathy. The HMW/total adiponectin ratio was not correlated with microangiopathy. Multiple regression analysis revealed that serum total and HMW adiponectin were independent factors for retinopathy stage (P = 0.0055 and P = 0.0027, respectively) and nephropathy stage (P = 0.0003 and P = 0.0018, respectively), when adjusted for age, gender, body mass index (BMI) and the duration of T2DM. This correlation remained significant when serum creatinine (or estimated glomerular filtration rate) and hypertension were added as independent variables. Treatment with thiazolidinediones (TZDs) did not affect these findings.

CONCLUSIONS

Serum total adiponectin and HMW adiponectin were found to be positively correlated with the severity of retinopathy and nephropathy but not with neuropathy in T2DM.

Effect of orlistat on eating behavior among participants in a 3-year weight maintenance trial

OBJECTIVE

To examine the effect of orlistat on dietary restraint, disinhibition, hunger, and binge eating and to understand the relation between changes in eating behavior and weight maintenance.

METHODS AND PROCEDURES

Subjects were 306 women and men (age: 19-45 years; BMI: 37.5 +/- 4.1 kg/m(2)) included in the Scandinavian Multicenter study of Obese subjects with the Metabolic Syndrome, a 3-year clinical trial of orlistat or placebo following an 8-week very low energy diet (VLED). Outcomes were changes in weight and in the Three Factor Eating Questionnaire (TFEQ) and Binge Eating Scale (BES) between screening and 17 and 33 months after randomization. As reported previously, weight gain following VLED was lower in subjects treated with orlistat than with placebo.

RESULTS

Compared to screening results, dietary restraint was increased and disinhibition, hunger, and binge eating were decreased in both groups. These changes were similar in both groups with the exception of the hunger score at month 33 that was reduced more in the placebo than in the orlistat group (difference between groups -1.1 (95% CI (-2.0, -0.2)) P = 0.014). In multivariate analyses, scores for restraint, disinhibition and binge eating were associated with weight loss after adjustment for BMI, gender, age, and treatment (all P < or = 0.002, model R (2) = 0.12-0.17).

DISCUSSION

Orlistat did not affect eating behavior differently in any substantial way than the placebo did in this long-term weight maintenance trial. The results indicate that increased restraint and decreased disinhibition and binge eating are important for sustained weight maintenance in obese subjects with the metabolic syndrome.

No association between INSIG2 Gene rs7566605 polymorphism and being overweight in Japanese population

Obesity is a complex trait reflecting numerous genetic and environmental factors. Recently, a common genetic polymorphism (rs7566605) associated with a higher BMI was found in proximity to the insulin induced protein 2 (INSIG2 ) gene, with replication in four unrelated populations living in Western countries. We investigated the susceptibility to the polymorphism amongst the general Japanese population (n = 1976). The frequency of appearance of the single-nucleotide polymorphism (SNP) in the Japanese (G allele; 0.652, C allele; 0.348) was not different from that found in subjects of European origin as reported previously. However, the BMI levels in each of these genotypes did not differ significantly (GG; 23 +/- 3, GC; 24 +/- 3, CC; 24 +/- 3 kg/m(2), P = 0.906). In a separate analysis according to sex (male; P = 0.462, female; P = 0.879), age decade (40s; P = 0.057, 50s; P = 0.998, 60s; P = 0.622, 70s; 0.425, respectively), and tertiles of the BMI (1st; P = 0.409, 2nd; P = 0.088, 3rd; P = 0.780), the differences did not achieve statistical significance. The frequency of obesity did not differ among the genotypes (25 kg/m(2); 30.3, 30.8, 28.2%, P = 0.729, 30 kg/m(2); 2.9, 3.8, 2.8%, P = 0.549). No associations were also observed for related plasma markers; high-molecular weight (HMW) adiponectin (P = 0.510), high-sensitive C-reactive protein (P = 0.788), resistin (P = 0.937) and homeostasis of minimal assessment of insulin resistance (P = 0.634). These results indicate a lack of association between SNP rs7566605 and being overweight among the Japanese (in the middle-aged and elderly population).

Body fat distribution and risk of coronary heart disease in men and women in the European Prospective Investigation Into Cancer and Nutrition in Norfolk cohort: a population-based prospective study

BACKGROUND

Body fat distribution has been cross-sectionally associated with atherosclerotic disease risk factors, but the prospective relation with coronary heart disease remains uncertain.

METHODS AND RESULTS

We examined the prospective relation between fat distribution indices and coronary heart disease among 24,508 men and women 45 to 79 years of age using proportional hazards regression. During a mean 9.1 years of follow-up, 1708 men and 892 women developed coronary heart disease. The risk for developing subsequent coronary heart disease increased continuously across the range of waist-hip ratio. Hazard ratios (95% CI) of the top versus bottom fifth of waist-hip ratio were 1.55 (1.28 to 1.73) in men and 1.91 (1.44 to 2.54) in women after adjustment for body mass index and other coronary heart disease risk factors. Hazard ratios increased with waist circumference, but risk estimates for waist circumference without hip circumference adjustment were lower by 10% to 18%. After adjustment for waist circumference, body mass index, and coronary heart disease risk factors, hazard ratios for 1-SD increase in hip circumference were 0.80 (95% CI, 0.74 to 0.87) in men and 0.80 (95% CI, 0.69 to 0.93) in women. Hazard ratios for body mass index were greatly attenuated when we adjusted for waist-hip ratio or waist circumference and other covariates.

CONCLUSIONS

Indices of abdominal obesity were more consistently and strongly predictive of coronary heart disease than body mass index. These simple and inexpensive measurements could be used to assess obesity-related coronary heart disease risk in relatively healthy men and women.

Hypoadiponectinemia as a marker of adipocyte dysfunction -- Part I: the biology of adiponectin

Adiponectin is the most abundantly secreted adipocyte-derived peptide hormone, possessing an array of antidiabetogenic and cardiovascular protective effects. Acting through 2 distinct membrane receptors, adiponectin receptors 1 and 2 (which utilize 5'-adenosine monophosphate-activated protein kinase phosphorylation, p38 mitogen-activated protein kinase, and peroxisome proliferator-activated receptor alpha as key cell signaling elements), adiponectin increases hepatic and skeletal muscle sensitivity to insulin, enhances fatty acid oxidation, suppresses monocyte-endothelial interaction, supports endothelial cell growth, lowers blood pressure, and moderates adipose tissue growth. The secretion of adiponectin can be suppressed by adipose factors, which are turned on once fat cell mass increases, such as cytokines, adipose renin-angiotensin system, and increased oxidative stress. Inhibition of adiponectin secretion results in the loss of an array of mechanisms, which under normal conditions of fat cell homeostasis provide protection from insulin resistance, diabetes, and atherosclerosis.

Adipose tissue, insulin resistance and low-grade inflammation: implications for atherogenesis and the cardiovascular harm of estrogen plus progestogen therapy

OBJECTIVE

To summarize recent findings providing mechanistic insight into why the relative presence of central to peripheral fat mass is a critical determinant of atherogenesis and why postmenopausal women with android obesity represent a risk population with increased susceptibility to the cardiovascular harm of estrogen plus progestin therapy (EPT).

METHODS

Review of own research and related literature in PubMed.

RESULTS

In postmenopausal women, android obesity characterized by excessive upper-body combined with relatively poorly developed lower-body fat mass is frequently associated with insulin resistance, low-grade inflammation, and early atherosclerosis. Underlying mechanisms involve disequilibrium between proinflammatory cytokines (high interleukin-6/C-reactive protein) and the anti-inflammatory adipokine (low adiponectin). Recent findings point out that women with abnormal glucose tolerance, a metabolic alteration closely linked to android adiposity, respond with increases in low-grade inflammation and accelerated atherogenesis to EPT that collectively may promote acute complications. We recently pointed out that a progestin could exert a dose-dependent inhibitory effect on circulating adiponectin. Thus, when EPT is prescribed to women with android obesity, further decreases in the protective adiponectin pool may become critical and act as a promoter of thromboembolic complications via its effects on plaque formation and stability. Since android obesity is associated with the highest levels of free estradiol, women with this phenotype might not be trivial candidates for EPT.

CONCLUSIONS

The herein summarized findings shed light on important interactions between sex steroids and body fat mass, with functional implications for cardiovascular risk. Since previous trials have not optimized the dose of the progestin for its effect on circulating adiponectin, utmost caution should be exercised in the prescription of available estrogen plus progestin therapies to women with android obesity and/or symptoms of the insulin resistance syndrome.

Cognitive performance in elderly women: significance of the 19bp insertion/deletion polymorphism in the 5' flank of the dopamine beta-hydroxylase gene, educational level, body fat measures, serum triglyceride, alcohol consumption and age

BACKGROUND

Genetic and environmental factors influence cognitive aging. The gene encoding dopamine beta-hydroxylase (DBH) could be one such factor since this hydroxylase converts dopamine to norepinephrine both of which are involved in cognition regulation.

OBJECTIVE

To assess the effect of the 19bp insertion/deletion polymorphism in the 5' flank of the DBH gene on cognitive performance in elderly women relative to other factors of cognitive aging.

METHODS

We examined a cross-sectional sample of 1371 postmenopausal women. Cognitive abilities were assessed by the 6-item orientation-memory-concentration test. The 19bp insertion/deletion polymorphism of the DBH gene was genotyped and apolipoprotein E (APOE) epsilon4 allele status was determined. In addition blood pressure, body fat mass and blood lipids were measured. Information was also obtained by personal interviews. Data were analyzed by regression analysis.

RESULTS

Cognition was univariately associated with DBH genotype (p = 0.04). A univariate association of borderline significance was observed for APOE epsilon4 allele status (p = 0.07). Exclusion of women with severe cognition impairment did not alter the strength of the association with the DBH gene polymorphism markedly (p = 0.06) but obliterated the weak association between APOE epsilon4 allele status and cognition. The association of the DBH gene polymorphism with cognition persisted after adjustment for other variables (p = 0.03).

CONCLUSIONS

The 19bp insertion/deletion polymorphism of the DBH gene influences cognition in elderly women and might have a stronger effect than APOE epsilon4 allele status on mild cognitive impairment. Both genetic polymorphisms had a significantly smaller impact on cognition than age, education, alcohol consumption and body fat measures.

Low Serum Testosterone and High Serum Estradiol Associate With Lower Extremity Peripheral Arterial Disease in Elderly Men

OBJECTIVES

This study sought to determine whether serum levels of testosterone and estradiol associate with lower extremity peripheral arterial disease (PAD) in a large population-based cohort of elderly men.

BACKGROUND

Few studies have explored the relationship between serum sex steroids and lower extremity PAD in men.

METHODS

The Swedish arm of the MrOS (Osteoporotic Fractures in Men) study (n = 3,014; average age 75.4 years) assessed ankle-brachial index (ABI) and defined lower extremity PAD as ABI <0.90. Radioimmunoassay measured serum levels of total testosterone, estradiol, and sex hormone-binding globulin, and we calculated free testosterone and free estradiol levels from the mass action equations.

RESULTS

A linear regression model including age, current smoking, previous smoking, diabetes, hypertension, body mass index, free testosterone, and free estradiol showed that free testosterone independently and positively associates with ABI (p < 0.001), whereas free estradiol independently and negatively associates with ABI (p < 0.001). Logistic regression analyses showed that free testosterone in the lowest quartile (vs. quartiles 2 to 4; odds ratio [OR] 1.65, 95% confidence interval [CI] 1.22 to 2.23, p = 0.001) and free estradiol in the highest quartile (vs. quartiles 1 to 3; OR 1.45, 95% CI 1.09 to 1.94, p = 0.012) independently associate with lower extremity PAD.

CONCLUSIONS

This cross-sectional study shows for the first time that low serum testosterone and high serum estradiol levels associate with lower extremity PAD in elderly men. Future prospective and interventional studies are needed to establish possible causal relationships between sex steroids and the development of lower extremity PAD in men.

Extreme obesity reduces bone mineral density: complementary evidence from mice and women

OBJECTIVE

To evaluate the effects of body adiposity on bone mineral density in the presence and absence of ovarian hormones in female mice and postmenopausal women.

RESEARCH METHODS AND PROCEDURES

We assessed percentage body fat, serum leptin levels, and bone mineral density in ovariectomized and non-ovariectomized C57BL/6 female mice that had been fed various calorically dense diets to induce body weight profiles ranging from lean to very obese. Additionally, we assessed percentage body fat and whole body bone mineral density in 37 overweight and extremely obese postmenopausal women from the Women's Contraceptive and Reproductive Experiences study.

RESULTS

In mice, higher levels of body adiposity (>40% body fat) were associated with lower bone mineral density in ovariectomized C57BL/6 female mice. A similar trend was observed in a small sample of postmenopausal women.

DISCUSSION

The complementary studies in mice and women suggest that extreme obesity in postmenopausal women may be associated with reduced bone mineral density. Thus, extreme obesity (BMI > 40 kg/m2) may increase the risk for osteopenia and osteoporosis. Given the obesity epidemic in the U.S. and in many other countries, and, in particular, the rising number of extremely obese adult women, increased attention should be drawn to the significant and interrelated public health issues of obesity and osteoporosis.