The associations between plasma adiponectin, ghrelin levels and cardiovascular risk factors

The Effect of Estrogen Replacement Therapy on Visceral Fat, Serum Glucose, Lipid Profiles and Apelin Level in Ovariectomized Rats

Objectives

Ovarian hormones have been shown to regulate body weight, intra-abdominal fat accumulation and plasma level of cytokines. The aim of this study was to investigate the effect of estrogen replacement therapy on visceral adipose tissue, plasma level of apelin, lipid profiles, and glucose in ovariectomized (OVX) rats.

Methods

Thirty female Wistar rats were divided into OVX (n = 20) and sham (n = 10) groups. OVX rats were subdivided into estrogen replacement therapy (OVX+est; n = 10) receiving 17 β-estradiol valerates (30 µg/kg, s.c., 5 day/week, for eight weeks), and vehicle control group receiving sesame oil same as experiment group (OVX+ses oil; n = 10). After the treatments, all groups were sacrificed and blood samples were collected, visceral fats were taken from the abdominal cavity and weighed immediately. Apelin were measured using enzyme-linked immunosorbent assay kits. Lipid profiles and glucose were measured using the enzymatic colorimetric method. Data were analyzed with one-way analysis of variance and (P < 0.05) determined as the statistical significance level.

Results

After eight weeks, body weight, body mass index (BMI), visceral fat, apelin and lipid profiles (P < 0.01) were increased significantly in OVX rats compared to sham group. Treatment with estrogen leads to significant reduction in body weight and BMI (P < 0.05), there was no significant change in serum apelin level in OVX+est rats compared to OVX+ses.

Conclusions

These results suggest that estradiol replacement therapy successfully attenuated some of the metabolic syndrome components, and apelin does not probably stand as a mediator of these physiological functions.

Assessing the Relationship Between Serum Ghrelin Levels and Metabolic Parameters and Autoimmunity in Patients with Euthyroid Hashimoto's Thyroiditis

OBJECTIVE

Hashimoto's thyroiditis (HT) may affect metabolic parameters and increase predisposition to obesity. In this study, we aimed to assess the relationships among serum ghrelin concentrations, metabolic parameters, and thyroid autoimmunity in euthyroid HT patients.

METHODS

The study included 48 euthyroid HT patients and 41 age- and sex-matched healthy controls. We assessed serum ghrelin, free triiodothyronine (T3), free thyroxine (T4), thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (anti-TPO), thyroglobulin antibody (anti-Tg), fasting blood glucose (FBG), insulin, lipid levels, and homeostasis model assessment insulin resistance (HOMA-IR) in all subjects.

RESULTS

Sex distribution, mean age, and body mass index (BMI) were similar in HT patients and controls (female/male, 42/6 vs. 33/8, 46.8 ± 14.7 vs. 45 ± 12.5 years, 28.5 ± 6.1 vs. 28.4 ± 4.9 kg/m2, respectively; P>.05 for all). The mean waist circumference (WC) of the HT group was significantly higher than that of the control group (100.6 ± 14.6 vs. 93.2 ± 13.2 cm, P = .015). While FBG, low-density lipoprotein cholesterol (LDL-C), and triglyceride levels in the HT group were significantly higher than in the control group, insulin levels and HOMA-IR were similar. Ghrelin levels were lower in HT patients compared to controls (416.9 ± 224.4 and 689.9 ± 191.6 pg/mL, respectively; P<.001). Ghrelin levels were similar in patients with low and high anti-TPO titers. Negative correlations were observed between ghrelin levels and BMI, WC, and anti-TPO levels. Regression analysis revealed that HT was the most important predictor of ghrelin levels.

CONCLUSION

Euthyroid HT is associated with a decrease in plasma ghrelin levels. Altered body fat distribution and increased anti-TPO levels do not seem to be directly involved in lower ghrelin levels in euthyroid HT patients.

Associations of adiponectin with individual European ancestry in African Americans: the Jackson Heart Study

BACKGROUND

Compared with European Americans, African Americans (AAs) exhibit lower levels of the cardio-metabolically protective adiponectin even after accounting for adiposity measures. Because few studies have examined in AA the association between adiponectin and genetic admixture, a dense panel of ancestry informative markers (AIMs) was used to estimate the individual proportions of European ancestry (PEA) for the AAs enrolled in a large community-based cohort, the Jackson Heart Study (JHS). We tested the hypothesis that plasma adiponectin and PEA are directly associated and assessed the interaction with a series of cardio-metabolic risk factors.

METHODS

Plasma specimens from 1439 JHS participants were analyzed by ELISA for adiponectin levels. Using pseudo-ancestral population genotype data from the HapMap Consortium, PEA was estimated with a panel of up to 1447 genome-wide preselected AIMs by a maximum likelihood approach. Interaction assessment, stepwise linear and cubic multivariable-adjusted regression models were used to analyze the cross-sectional association between adiponectin and PEA.

RESULTS

Among the study participants (62% women; mean age 48 ± 12 years), the median (interquartile range) of PEA was 15.8 (9.3)%. Body mass index (BMI) (p = 0.04) and insulin resistance (p = 0.0001) modified the association between adiponectin and PEA. Adiponectin was directly and linearly associated with PEA (β = 0.62 ± 0.28, p = 0.03) among non-obese (n = 673) and insulin sensitive participants (n = 1141; β = 0.74 ± 0.23, p = 0.001), but not among those obese or with insulin resistance. No threshold point effect was detected for non-obese participants.

CONCLUSIONS

In a large AA population, the individual proportion of European ancestry was linearly and directly associated with plasma adiponectin among non-obese and non insulin-resistant participants, pointing to the interaction of genetic and metabolic factors influencing adiponectin levels.

A meta-analysis of genome-wide association studies for adiponectin levels in East Asians identifies a novel locus near WDR11-FGFR2

Blood levels of adiponectin, an adipocyte-secreted protein correlated with metabolic and cardiovascular risks, are highly heritable. Genome-wide association (GWA) studies for adiponectin levels have identified 14 loci harboring variants associated with blood levels of adiponectin. To identify novel adiponectin-associated loci, particularly those of importance in East Asians, we conducted a meta-analysis of GWA studies for adiponectin in 7827 individuals, followed by two stages of replications in 4298 and 5954 additional individuals. We identified a novel adiponectin-associated locus on chromosome 10 near WDR11-FGFR2 (P = 3.0 × 10(-14)) and provided suggestive evidence for a locus on chromosome 12 near OR8S1-LALBA (P = 1.2 × 10(-7)). Of the adiponectin-associated loci previously described, we confirmed the association at CDH13 (P = 6.8 × 10(-165)), ADIPOQ (P = 1.8 × 10(-22)), PEPD (P = 3.6 × 10(-12)), CMIP (P = 2.1 × 10(-10)), ZNF664 (P = 2.3 × 10(-7)) and GPR109A (P = 7.4 × 10(-6)). Conditional analysis at ADIPOQ revealed a second signal with suggestive evidence of association only after conditioning on the lead SNP (Pinitial = 0.020; Pconditional = 7.0 × 10(-7)). We further confirmed the independence of two pairs of closely located loci (<2 Mb) on chromosome 16 at CMIP and CDH13, and on chromosome 12 at GPR109A and ZNF664. In addition, the newly identified signal near WDR11-FGFR2 exhibited evidence of association with triglycerides (P = 3.3 × 10(-4)), high density lipoprotein cholesterol (HDL-C, P = 4.9 × 10(-4)) and body mass index (BMI)-adjusted waist-hip ratio (P = 9.8 × 10(-3)). These findings improve our knowledge of the genetic basis of adiponectin variation, demonstrate the shared allelic architecture for adiponectin with lipids and central obesity and motivate further studies of underlying mechanisms.

Changes in ghrelin and asymmetrical dimethylarginine in obese Mexican adolescents after six-month lifestyle intervention

The aim of this study was to evaluate the effect of a six-month lifestyle intervention on ghrelin and asymmetrical dimethylarginine (ADMA) in obese Mexican adolescents. A total of 65 obese Mexican adolescents aged 10-16 years completed a six-month lifestyle intervention. Anthropometric and biochemical parameters were assessed at baseline and at six months. Twenty normal-weight adolescents were also evaluated at baseline. Insulin resistance (IR) was determined by the homeostasis model assessment of IR (HOMA-IR). Ghrelin and ADMA were determined by enzyme-linked immunosorbent assay. Obese adolescents presented significantly higher triglycerides, cholesterol, glucose, insulin, HOMA-IR, and ADMA levels, while ghrelin was significantly lower. The lifestyle intervention led to a significant improvement in HOMA-IR, ghrelin, and ADMA in the whole studied obese subjects. ADMA and ghrelin levels were associated with BMI and IR components. According to the value of HOMA-IR, the obese subjects were divided into subjects with or without IR, no difference in ghrelin and ADMA was observed in these two subgroups. After intervention, the obese with IR showed increased ghrelin and decreased ADMA, while the obese without IR only showed improvement in ghrelin. The multiple linear regression analysis revealed that the changes of systolic blood pressure were the only predictor for the changes of ghrelin in the obese with IR. Our study demonstrated the increase of ADMA and the decrease of ghrelin in obese adolescents. Lifestyle intervention improved insulin resistance, decreased ADMA, and increased ghrelin in obese subjects with IR although no significant weight loss was observed.

Low serum adiponectin concentrations are associated with insulin sensitivity independent of obesity in Sudanese subjects with type 2 diabetes mellitus

AIMS

Prevalence of Type 2 diabetes mellitus among Sudanese population was found to be 3.4% and associated with high rates of complications and obesity. Different adipocytokines are secreted from adipose tissues, among them adiponectin, which was shown to have insulins ensitizing properties and anti-inflammatory, anti-atherogenic effect. The aim of this study was to characterize type 2 diabetes in Sudanese diabetic subjects and controls in respect to hormones influencing or influenced by glucose metabolism.

METHODS

104 type 2 diabetic patients (45 men and 59 women), and 75 matched control subjects (34 men and 41 women) were studied. Fasting serum samples were used to measure adiponectin, leptin, insulin, proinsulin, ghrelin and glucose. Body mass index, insulin/proinsulin ratio and (HOMA) insulin resistance and beta cell function were also calculated.

RESULTS

Adiponectin serum concentrations were significantly lower in subjects with type 2 diabetes compared with controls subjects (P = 0.002), comparison between males and females did not reach significant levels in both diabetic (P = 0.06) or controls (P = 0.16) groups. In the diabetic group adiponectin correlated positively with serum glucose, negatively with serum proinsulin and HOMA beta cell function (P = 0.03) respectively and serum ghrelin (P = 0.003), but not with BMI, HOMA insulin resistance, insulin or leptin. In controls serum adiponectin correlated negatively with BMI (P = 0.002) but not with other variables.

CONCLUSIONS

The findings of this study suggest that, adiponectin concentrations independent on BMI as a measure of adiposity, were mostly linked to insulin sensitivity and not to insulin resistance in Sudanese type 2 diabetic subjects, where race specific regulation mechanisms or different type 2 diabetes phenotype suggested being a major contributory factor in clarification the findings of this study.

Adjunctive effects of aripiprazole on metabolic profiles: comparison of patients treated with olanzapine to patients treated with other atypical antipsychotic drugs

Metabolic abnormalities are serious adverse effects of atypical antipsychotic treatment. This study aims to determine the effects of adjunctive aripiprazole on metabolic profiles among patients receiving treatment with atypical antipsychotics, and to examine whether these effects are different from that of pre-existing atypical antipsychotics. In the 8-week open-label trial, aripiprazole was added to patients who were receiving treatment with atypical antipsychotics and had experienced weight gain or dyslipidemia. The dosage of pre-existing atypical antipsychotics was fixed, while the dosage of aripiprazole ranged from 5 to 20 mg/day during the study period. Metabolic profiles, including body weight, body mass index (BMI), plasma levels of fasting glucose, triglycerides, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and adiponectin, were measured at baseline and week 8. As a result, 43 subjects (16 males and 27 females, mean age: 37.8±10.8 years) completed the study. The pre-existing antipsychotics were olanzapine (n=12), risperidone (n=19), quetiapine (n=6) and amisulpiride (n=6). The mean dosage of adjunctive aripiprazole was 9.9±3.2 mg/day. After the aripiprazole-augmented regimen for 8 weeks, patients treated with olanzapine had significant decreases in body weight, BMI and triglyceride levels, and had significant increases in adiponectin levels. For patients treated with other atypical antipsychotics, none of the metabolic parameters significantly changed after administering aripiprazole. In conclusion, aripiprazole-augmented treatment might be beneficial for the metabolic regulation of patients being treated with a stable dose of olanzapine, but not for those treated with other atypical antipsychotics. A long-term, randomized, double-blind controlled design is suggested to confirm these findings.

Adipocytokine profiles in a putative novel postmenopausal polycystic ovary syndrome (PCOS) phenotype parallel those in premenopausal PCOS: the Rancho Bernardo Study

The objective was to investigate whether the associations between leptin, adiponectin, andadiposity reported in classic polycystic ovary syndrome (PCOS) are also observed in elderly women with a novel putative postmenopausal PCOS phenotype. We studied 713 postmenopausal community-dwelling women. Diagnosis of the novel phenotype required the presence of ≥3 diagnostic features including: 1) a personal history of oligomenorrhea; 2) history of infertility or miscarriage; 3) current or past clinical or hormonal evidence of hyperandrogenism; 4) central obesity; 5) biochemical evidence of insulin resistance. Women in the control group had ≤2 of these components. Mean age (±SD) was 74±8 years for the study cohort. Sixty-six women (9.3%) had the putative PCOS phenotype. Serum leptin was higher (mean 25.70±15.67 vs 14.94+9.89 ng/mL, P<.01) and adiponectin lower (mean 11.72±4.80 vs 17.31±7.45 μg/mL, P<.01) in cases vs controls. Leptin was positively, and adiponectin inversely, associated with an increasing number of phenotype features (P<.01 for linearity). In age-adjusted regression analysis, adjustment for waist circumference eliminated the association between leptin and the PCOS phenotype, but not the association between adiponectin and the PCOS phenotype. In this novel postmenopausal PCOS phenotype, adipocytokine profiles and their associations with adiposity parallel those reported in younger women with classic PCOS. These results support our hypothesis that a putative phenotype analogous to PCOS can be identified in postmenopausal women using clinical and biochemical criteria. Use of this novel phenotype could provide a basis for studies of the delayed consequences of PCOS in older women.

Adiponectin, Non-Esterified Fatty Acids and Antiphospholipid Antibodies in Type II Diabetes Mellitus

The importance of the association of antiphospholipid antibodies (aPL Abs) with the features of type II diabetes mellitus has not yet been elucidated. The aim of this work was to investigate the association of aPL Abs with adiponectin and non-esterified fatty acids (NEFA) in type II diabetes mellitus patients without micro and/or macrovascular complications, and to analyze the differences between the male and female patients with regard to the abovementioned parameters. Male patients with type II diabetes mellitus showed a positive correlation between NEFA concentrations and anti-oxLDL antibodies (r=0.334, p=0.019). A weak, but statistically significant correlation between adiponectin concentrations and the IgM isotype of anti-annexin A5 antibodies was found in type II diabetes mellitus patients (r=0.285, p=0.011). The presence of a positive correlation between NEFA and anti-oxLDL antibodies might be useful in the detection of patients with premature atherosclerosis in type II diabetes mellitus patients without any micro and/or macrovascular complications among type II diabetes mellitus patients.

Factors associated with plasma ghrelin level in Japanese general population

OBJECTIVE

Ghrelin is a novel gastric peptide identified in 1999 as a 'hunger hormone'. Plasma ghrelin level is decreased in human obesity. Factors associated with ghrelin have been mainly investigated in western countries where the prevalence of obesity is high. The aim of this study is to examine factors associated with plasma ghrelin in a Japanese general population where obesity is not so common.

METHODS

Fasting ghrelin levels were measured by ELISA in 638 subjects in 2005-2007. We measured body mass index (BMI), waist circumference and blood pressure. Blood was drawn in the morning after a 12-h fast for determinations of ghrelin, lipid, glucose (FPG), insulin, estimated glomerular filtration rate (eGFR) and uric acid levels. Univariate and multiple stepwise regression analyses were performed to find out factors associated with ghrelin.

RESULTS

In our population, the mean BMI was 23·8 kg/m(2) , indicating a nonobese population. Results of univariate analysis showed that age (P<0·001), BMI (P<0·001), waist (P<0·001), triglycerides (P<0·01), FPG (P<0·01), insulin (P<0·001) and uric acid (P<0·05) were inversely associated with ghrelin. High-density lipoprotein (HDL) cholesterol (P<0·001) and eGFR (P<0·05) were positively associated with ghrelin. Men had lower ghrelin levels than women (P<0·001). Results of the multiple stepwise regression analysis revealed that age (P<0·001; inversely), female gender (P<0·001), insulin (P<0·001; inversely), HDL cholesterol (P=0·005), BMI (P=0·01; inversely) and uric acid (P=0·045; inversely) were significantly and independently associated with ghrelin.

CONCLUSIONS

The present study demonstrated that age and gender affected plasma ghrelin levels more than BMI. This may well be because of the low prevalence of overweight in our population.

Alanine aminotransferase decreases with age: the Rancho Bernardo Study

Background

Serum alanine aminotransferase (ALT) is a marker of liver injury. The 2005 American Gastroenterology Association Future Trends Committee report states that serum ALT levels remain constant with age. This study examines the association between serum ALT and age in a community-dwelling cohort in the United States.

Methods

A cross-sectional study of 2,364 (54% female) participants aged 30–93 years from the Rancho Bernardo Study cohort who attended a research clinic visit in 1984–87. Demographic, metabolic co-variates, ALT, bilirubin, gamma glutamyl transferase (GGT), albumin, and adiposity signaling biomarkers (leptin, IL-6, adiponectin, ghrelin) were measured. Participants were divided into four-groups based upon age quartile, and multivariable-adjusted least squares of means (LSM) were examined (p for trend <0.05).

Results

ALT decreased with increasing age, with mean ALT levels (IU/L) of 23, 21, 20, and 17 for those between quartile ages 30–62, 63–71, 72–77, and 78–93 years (p<0.0001). Trends of decreasing LSM ALT with age and the decreasing prevalence of categorically defined elevated serum ALT with age remained robust after adjusting for sex, alcohol use, metabolic syndrome components, and biomarkers of adiposity (p-value <0.0001), and was not materially changed after adjusting for bilirubin, GGT, and albumin.

Conclusions

ALT levels decrease with age in both men and women independent of metabolic syndrome components, adiposity signaling biomarkers, and other commonly used liver function tests. Further studies are needed to understand the mechanisms responsible for a decline in ALT with age, and to establish the optimal cut-point of normal ALT in the elderly.

The effects of macronutrient intake on total and high-molecular weight adiponectin: results from the OMNI-Heart trial

Higher levels of the adipocyte-specific hormone adiponectin have been linked to increased high-density lipoprotein (HDL) and lower insulin resistance. This study was conducted to determine the influence of macronutrient intake on adiponectin levels. One hundred and sixty-four pre- and stage-1 hypertensive adults participated in the Optimal Macro-Nutrient Intake Heart (OMNI-Heart) trial, a crossover feeding study originally testing the effects of macronutrients on blood pressure. Participants underwent three 6-week feeding periods: one rich in carbohydrates (CARB), one rich in monounsaturated fat (MUFA), and one rich in protein (PROT), while maintaining body weight. Their median plasma high molecular weight (HMW) and total adiponectin levels were 2.3 and 8.2 microg/ml, respectively, resulting in an average of 27% HMW adiponectin. Both HMW and total adiponectin levels decreased after baseline while the percent HMW adiponectin remained unchanged. Between diets, the MUFA diet maintained a higher level of both HMW and total adiponectin levels than either the CARB (HMW: +6.8%, P = 0.02; total: +4.5%, P = 0.001) or PROT (HMW: +8.4%, P = 0.003; total: +5.6%, P < 0.001) diets. Changes in total adiponectin levels were positively correlated to changes in HDL cholesterol irrespective of diets (Spearman r = 0.22-0.40). No correlation was found between changes in lipids, blood pressure, or insulin resistance by the homeostasis model assessment (HOMAIR). Macronutrient intake has effects on HMW and total adiponectin levels independent of weight loss. A diet rich in MUFA was associated with higher levels of total and HMW adiponectin in comparison to a carbohydrate- or protein-rich diet. Effects seen in adiponectin paralleled those found with HDL cholesterol.

Adipokines and cardiometabolic function: How are they interlinked?

OBJECTIVE

Adipokines contribute directly to the coexistence of insulin resistance and endothelial dysfunction. Most studies focus on a single adipokine. We therefore investigated the independent relationships of leptin, adiponectin, tumor necrosis factor-alpha, resistin and visfatin, as well as the gut hormone ghrelin with blood pressure and insulin resistance. Secondly we evaluated the interrelationships of adipokines and ghrelin in concert with various cardiometabolic markers.

METHODS AND RESULTS

Caucasian women (N=115) with varying levels of obesity (aged 31.3 + or - 9.18 years) were included. Significant correlations of leptin, adiponectin, ghrelin and visfatin with mean arterial pressure (p<0.05) disappeared after adjustment for age, body mass index and waist circumference. But significant correlations with insulin resistance (HOMA) (for leptin, adiponectin and ghrelin) remained significant after adjustments. Factor analyses yielded five factors, but two main clusters, namely a metabolic syndrome cluster (including leptin, adiponectin and ghrelin) and a vascular atherosclerotic cluster (including tumor necrosis factor-alpha, visfatin and resistin).

CONCLUSION

Factor analyses identified patterns which indicate specific roles of the various adipokines. Leptin, adiponectin and ghrelin were more closely related to insulin resistance and central obesity as core components of the metabolic syndrome. Visfatin, tumor necrosis factor-alpha and resistin seem to direct their effects onto the vascular system possibly by means of mechanisms such as inflammation, vasoconstriction and coagulation.

Short- and long-term relationships of serum ghrelin with changes in body composition and the metabolic syndrome in prepubescent obese children following two different weight loss programmes

OBJECTIVES

Ghrelin has been proposed to be a regulator of energy balance, and its dysregulation may be important in obesity. The aims of this study were (i) to compare short- and long-term changes in circulating ghrelin concentration after increasing energy expenditure vs. its changes after decreasing energy intake, (ii) to determine factors associated with changes in ghrelin level, and (iii) to assess relationships of ghrelin concentration with metabolic syndrome (MetS) in prepubescent obese children.

DESIGN

Randomized controlled trial.

PATIENTS

About 100 obese children aged 7-9 years.

MEASUREMENTS

After baseline testing, children were randomly assigned to two interventional groups, either receiving dietary recommendations or engaging in physical training classes for 6 months. Ghrelin, insulin, leptin, fasting blood sugar, lipid profile and anthropometric indexes, as well as energy intake and expenditure were measured.

RESULTS

Of the participants, 92 completed the 6-month trial, and 87 returned for the 1-year follow-up. Except ghrelin level, other biochemical variables had no significant change at 12- vs. 6-month follow-up. In both groups, ghrelin showed a progressive increase in the periods of time with significant reduction of overweight and negative energy balance; while after the end of the trial, when children regained weight, it decreased toward baseline levels. Baseline ghrelin had strong negative correlation with measures of central obesity. The odds of having the MetS were 12% lower in the middle and 37% lower in the highest tertile of ghrelin level. As the number of MetS components increased, there was a progressive decrease in ghrelin and quantitative insulin sensitivity check index (QUICKI), with a progressive increase in serum insulin, HOMA-R and leptin levels.

CONCLUSIONS

Ghrelin increases in response to overweight reduction and negative energy balance resulting from either an exercise intervention or reduction in food intake in prepubescent obese children. It is unlikely to regulate long-term energy balance in young obese children.

Circulating ghrelin, leptin, and soluble leptin receptor concentrations and cardiometabolic risk factors in a community-based sample

CONTEXT

The conjoint effects and relative importance of ghrelin, leptin, and soluble leptin receptor (sOB-R), adipokines involved in appetite control and energy expenditure in mediating cardiometabolic risk, is unknown.

OBJECTIVE

The objective of the study was to study the cross-sectional relations of these adipokines to cardiometabolic risk factors in a community-based sample.

DESIGN, SETTING, AND PARTICIPANTS

We measured circulating ghrelin, leptin, and sOB-R in 362 participants (mean age 45 yr; 54% women) of the Framingham Third Generation Cohort.

MAIN OUTCOME MEASURES

Body mass index, waist circumference (WC), blood pressure, lipid measures, fasting glucose, smoking, and metabolic syndrome (MetS) were measured.

RESULTS

Ghrelin and leptin concentrations were significantly higher in women (P < 0.0001). In multivariable models, ghrelin was inversely associated with age and systolic blood pressure, and leptin was positively related to body mass index and WC. sOB-R was positively associated with age, total cholesterol, and fasting glucose and inversely with WC and high-density lipoprotein cholesterol. Ghrelin and sOB-R concentrations were significantly lower with number of MetS components (P for trend = 0.022 and < 0.0001, respectively), whereas leptin concentrations were higher (P for trend = 0.0001). Relating all adipokines to MetS conjointly, higher ghrelin and leptin concentrations were associated with decreased and increased odds of MetS (odds ratio 0.55, P < 0.0001; odds ratio 4.44, P = 0.0002, per 1 sd increase of respective log adipokine).

CONCLUSIONS

In our community-based sample, we observed a sexual dimorphism in circulating ghrelin and leptin concentrations. Ghrelin, leptin, and sOB-R were associated with number of MetS components cross-sectionally, consistent with the hypothesis that these adipokines may have a central role in cardiometabolic risk.

Ghrelin and obestatin levels in severely obese women before and after weight loss after Roux-en-Y gastric bypass surgery

BACKGROUND

Ghrelin and obestatin are derived from the same gene but have different effects: Ghrelin stimulates appetite, and previous-albeit inconsistent-data show that obestatin may be involved in satiety. The present study was designed to test the hypothesis that Roux-en-Y gastric bypass (RYGB) surgery and/or the weight loss that reliably results from this procedure would alter levels of ghrelin and obestatin and ghrelin/obestatin ratios in a cohort of morbidly obese women.

METHODS

This is a longitudinal follow-up study in 18 morbidly obese women (mean weight 131.2 kg, mean body mass index [BMI] 47.4). Clinical parameters and fasting serum concentrations of ghrelin, obestatin, triglycerides, low-density lipoprotein cholesterol, glucose, and insulin were measured before and 2 years after RYGB surgery, which was associated with body weight reductions of 41.5 +/- 11.6 kg (mean 62.5% excess weight loss).

RESULTS

Ghrelin concentrations (-12%, p = 0.022) and ghrelin/obestatin ratios (-14%, p = 0.017) were lower after surgery than before, while obestatin levels did not change. Changes in ghrelin concentrations correlated with changes in insulin levels (r = 0.45, p = 0.011). Most cardiovascular risk factors studied improved postsurgically (p < 0.01).

CONCLUSION

In contrast to previous weight loss studies involving gastric banding, ghrelin levels decreased and obestatin levels remained stable after massive weight loss in long-term follow-up. The favorable gastrointestinal hormone profiles observed are likely to contribute to the long-term weight loss success rate attributed to RYGB.

Obestatin and ghrelin levels in obese children and adolescents before and after reduction of overweight

OBJECTIVES

Obestatin and ghrelin, which are derived from the same gene, are observed to have opposite effects on weight status. The aims of this study were to compare obestatin concentrations in obese and normal-weight children and to analyse the effect of weight loss on obestatin and ghrelin levels.

METHODS

We examined anthropometrical markers and fasting serum obestatin, ghrelin, leptin, glucose and insulin concentrations in 44 obese children (mean age 11.2 years) before and after participating in a 1-year outpatient obesity intervention programme based on a high-carbohydrate, fat-reduced diet and increased physical activity. Additionally, total ghrelin, obestatin and leptin levels were determined in 22 normal-weight healthy children of similar age, gender and pubertal stage.

RESULTS

Obestatin and leptin concentrations were significantly (P < 0.001) higher and ghrelin concentrations were significantly (P < 0.001) lower in obese children compared to nonobese children. In contrast to the 13 children without weight loss, substantial weight loss in 31 children led to a significant (P = 0.007) increase in obestatin and to a significant (P < 0.05) decrease in leptin and insulin concentrations, while ghrelin concentrations did not change significantly. Children with substantial weight loss demonstrated significantly (P = 0.009) lower obestatin and a tendency (P = 0.064) to higher ghrelin concentrations at baseline. Changes in insulin were not related to changes in ghrelin or obestatin.

CONCLUSION

The increase in obestatin and the decrease in ghrelin in obese children point towards an adaptation process of weight status. Weight reduction due to a long-term lifestyle intervention resulted in an increase in obestatin levels.

Adipocytokine and ghrelin levels in relation to cardiovascular disease risk factors in women at midlife: longitudinal associations

BACKGROUND

There are limited data concerning the relationships between changes in adipocytokines and cardiovascular disease (CVD) risk factors.

OBJECTIVE

To examine the longitudinal associations between leptin, adiponectin, resistin and ghrelin levels and CVD risk factor levels in women at midlife.

DESIGN

Prospective, observational study.

SUBJECTS AND MEASUREMENTS

Leptin, adiponectin, resistin, ghrelin levels and CVD risk factors were measured in specimens collected from 40 women at 3 points in time corresponding to the pre-, peri- and postmenopause stages of their natural menopause transition.

RESULTS

In longitudinal analyses adjusted for CVD risk factors and leptin at the previous menopausal stage, aging, education, smoking and physical activity, greater increases in leptin over the menopause transition were associated with greater decreases in high-density lipoprotein cholesterol (HDL-c) and greater increases in diastolic blood pressure, glucose, insulin and insulin resistance (all P < 0.05). Larger decreases in adiponectin over the menopause transition were associated with greater increases in systolic blood pressure, insulin and insulin resistance and with greater decreases in HDL-c. Greater increases in ghrelin levels over the menopausal transition were associated with greater low-density lipoprotein cholesterol increases (P = 0.014). Resistin was not associated with CVD risk factor changes.

CONCLUSION

There were significant adverse associations of adipocytokines and ghrelin with multiple CVD risk factor changes in women across midlife. Given that this time period is dynamic for CVD risk, these data underscore the need for additional prospective studies.

Controversy in diagnosis and management of the metabolic syndrome

Far more work remains to be done to unravel the tangled web of pathophysiology responsible for the metabolic syndrome. This article addresses several aspects of the current controversy surrounding the metabolic syndrome: (1) definition of the metabolic syndrome; (2) evidence for and against the use of the metabolic syndrome as a cardiovascular disease risk predictor; (3) evidence as to underlying pathophysiology; and (4) evidence for treatment of the metabolic syndrome (as opposed to components of the syndrome) in a risk reduction strategy to prevent type 2 diabetes mellitus or cardiovascular disease.

A comparison of oral and transdermal short-term estrogen therapy in postmenopausal women with metabolic syndrome

OBJECTIVE

To determine whether it would be preferable to prescribe oral or transdermal estrogen to symptomatic postmenopausal women with metabolic syndrome (MBS).

DESIGN

Prospective, randomized study.

SETTING

Academic medical center.

PATIENT(S)

Fifty obese postmenopausal women with MBS.

INTERVENTION(S)

Women were randomized to receive either oral E(2) (oE(2), 1 mg/d) or transdermal E(2) (tE(2), 0.05 mg/d) for 3 months. Fasting blood was obtained before and after treatment for glucose, insulin, lipid profiles, the adipocytokines (adiponectin, leptin, and resistin), and a gastric peptide (ghrelin). In addition, a 75-g 2-hour oral glucose-tolerance and intravenous insulin-tolerance tests were performed before and after E(2).

MAIN OUTCOME MEASURE(S)

Changes in parameters of insulin resistance (IR), lipid profiles, and adipocytokine levels.

RESULT(S)

Mean serum concentrations of E(2) in women using oE(2) and tE(2) were 39.1 +/- 5.6 and 49.2 +/- 28.6 pg/mL, respectively. After oE(2), there was a statistically significant worsening of IR markers, including an increase in baseline insulin (15.28 +/- 1.27 to 22.02 +/- 2.40 microU/mL), a reduction in quantitative insulin-sensitivity check index (0.3177 +/- 0.0043 to 0.2977 +/- 0.0057), and an increase in homeostasis model assessment (3.96 +/- 0.38 to 8.59 +/- 2.08). The only significant change in the lipid profile was an increase in high-density-lipoprotein cholesterol (50.46 +/- 2.34 vs. 55.08 +/- 2.51 mg/dL). Leptin levels increased (81.43 +/- 7.87 ng/mL to 94.10 +/- 6.56 ng/mL), and adiponectin decreased nonsignificantly, resulting in an increased leptin-adiponectin ratio (12.56 +/- 1.70 to 15.86 +/- 2.24); resistin levels increased (9.37 +/- 1.09 ng/mL to 11.72 +/- 1.10 ng/mL); and baseline ghrelin levels decreased (701.64 +/- 59.79 pg/mL to 581.72 +/- 36.07 pg/mL). After tE(2), no significant changes in IR parameters occurred, except for a decrease in glucose-insulin ratio. There were no changes in lipid parameters. Leptin did not change (72.7 +/- 9.3 ng/mL to 78.8 +/- 7.9 ng/mL), whereas adiponectin levels showed statistically significant increase (7.97 +/- 0.7 microg/mL vs. 9.96 +/- 1.1 microg/mL), with no change in the leptin-adiponectin ratio. Resistin levels did not change significantly, and ghrelin levels decreased (888.52 +/- 109.98 pg/mL vs. 579.04 +/- 39.30 pg/mL).

CONCLUSION(S)

This short-term study suggests that oral E(2) may worsen IR and adipocytokine parameters, worsening cardiovascular risk. Transdermal E(2) had minimal effects on IR and resulted in higher adiponectin. Although these data may not reflect alterations that occur with estrogen therapy in more metabolically normal postmenopausal women or with longer term therapy, the findings suggest that tE(2) may be a preferable treatment for obese women with MBS. Long-term studies are needed to make any recommendations.

Serum Ghrelin Levels in patients with Hashimoto's thyroiditis

OBJECTIVE

Hypothyroidism is associated with changes in appetite and body weight. Ghrelin is an orexigenic peptide, and it stimulates appetite and increases food intake. However, the potential relationship between circulating ghrelin levels, hypothyroidism, and thyroid antibodies has not been adequately studied.

DESIGN

Forty-seven patients with hypothyroidism due to Hashimoto's thyroiditis and 48 euthyroid subjects were enrolled in the study. Thyroid hormones and antibodies, insulin, glucose, ghrelin levels, and lipid parameters were measured in all the subjects.

MAIN OUTCOME

Hypothyroid group showed significantly decreased serum levels of ghrelin and ghrelin=body mass index (BMI) compared to euthyroid group (31.9 +/- 21.5 pg/mL vs. 50.5 +/- 34.8 pg/mL, p < 0.001; and 1.24 +/- 0.93 vs. 2.12 +/- 1.53, p < 0.0001). In hypothyroid group, 6 months after treatment, ghrelin levels and ghrelin/BMI remained lower than euthyroid group (33.2 +/- 21.1 pg/mL vs. 50.5 +/- 34.8 pg/mL, p < 0.001; and 1.27 +/- 0.86 vs. 2.12 +/- 1.53, p < 0.0001). Ghrelin levels were decreased in hypothyroid patients with high thyroid peroxidase antibody (TPOAb) titre compared to hypothyroid patients with low TPOAb titre (19.1 +/- 23.1 pg/ mL vs. 35.3 +/- 17.4 pg/mL, p < 0.01). Ghrelin levels correlated positively with free triiodothyronine (FT3) and free thyroxine (FT4), and negatively with age, thyroglobulin antibody (TAb), TPOAb, total cholesterol (T-C), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), and triglycerides (TG) in hypothyroid group. In euthyroid group, circulating ghrelin levels correlated negatively with age, FT3, FT4, TG, and VLDL-C levels. No significant correlation was observed between ghrelin and homeostasis model assessment for insulin resistance (HOMA-IR) and between ghrelin and quantitative insulin sensitivity check index (QUICKI) in both groups. Regression analysis revealed that FT3 level is the most important predictor of ghrelin levels.

CONCLUSION

Thyroid hormones and antibodies seem to have a potential effect on serum ghrelin levels in patients with hypothyroidism.

Aging influences the level and functions of fasting plasma ghrelin levels: the POWIRS-Study

OBJECTIVE

Ghrelin, known for its orexigenic activity, also have functions such as vasodilation and a growth hormone releasing action. It is uncertain whether these functions change with increasing age. This study aimed to determine whether ghrelin levels differ between young and older women with different levels of obesity; and secondly whether the associations of ghrelin with metabolic syndrome (MS) components, adipocytokines, coagulation factors, and cortisol change with increasing age.

METHODS AND RESULTS

Caucasian women (N=107) were divided into young (19-29 years) and older groups (30-56 years). Fasting ghrelin, leptin, adiponectin, glucose, insulin, cortisol, fibrinogen and plasminogen activator inhibitor-1 (PAI-1) levels were determined. Blood pressure (BP), body mass index and waist circumferences were measured. Older lean women showed lower levels of ghrelin (p<0.05) than young lean women, with no differences regarding BP, obesity, lipids, adipokines or insulin resistance (IR). Ghrelin levels of older women remained constant with increasing obesity, but younger women showed significantly reduced ghrelin levels in obese groups. Only younger women showed significant correlations between ghrelin and leptin, adiponectin, fibrinogen and PAI-1 (adjusted for age, obesity and menstrual phase), whereas both age groups showed significant correlations with IR. In younger women factor analysis grouped ghrelin with coagulation factors and all MS components. In older women ghrelin was absent from the MS cluster, but was associated with lower BP, cortisol and IR.

CONCLUSIONS

Ghrelin levels were not significantly elevated in lean older women, and did not change with increased obesity in older women--as were observed in younger women. The functions of ghrelin also seem to change with increased age since only in young women ghrelin was associated with obesity, coagulation factors and leptin.

Sex-specific determinants of serum adiponectin in older adults: the role of endogenous sex hormones

OBJECTIVE

To assess the sex-specific association of adiponectin with multiple factors thought to influence its levels, with a special emphasis on endogenous sex hormones.

DESIGN AND METHODS

A cross-sectional study of determinants of serum adiponectin in 873 men and 673 postmenopausal women, ages 50-92. Factors evaluated include age, body size, fat distribution, lifestyle (exercise, smoking, alcohol intake), insulin resistance, renal function and endogenous sex hormone levels (total and bioavailable testosterone and estradiol).

RESULTS

Median serum adiponectin was 50% higher in women than men (P<0.001). In unadjusted analyses, adiponectin was positively related to age, alcohol intake, high-density lipoprotein (HDL) and testosterone, and negatively related to waist girth, body mass index, Homeostasis Model Assessment for Insulin Resistance (HOMA-IR), triglycerides and bioavailable estradiol in both sexes (all P<0.01). Adiponectin was positively related to blood urea nitrogen, a measure of renal function, in men only (P<0.001). Sex-specific multivariate linear regressions adjusting for HDL and triglycerides showed that only age, HOMA-IR and sex hormones independently predicted circulating adiponectin for both men and women. Higher levels of endogenous testosterone and lower bioavailable estradiol concentrations each predicted higher adiponectin; this was true for both sexes, and was not explained by differences in age, adiposity, alcohol intake, insulin resistance or lipoprotein levels.

CONCLUSIONS

The association of adiponectin with the factors studied here is strikingly similar for men and women. Sex differences in circulating adiponectin levels in older adults cannot be explained by sex hormone regulation.

Reduced Serum Acylated Ghrelin Levels in Patients with Hyperthyroidism

BACKGROUND AND OBJECTIVE

Recent studies have revealed that circulating ghrelin levels seem to play a role in energy homeostasis. The effect of hyperthyroidism on ghrelin levels is not fully known.

METHODS

Serum levels of ghrelin and its relationship with insulin resistance were evaluated in 48 patients with hyperthyroidism and 43 euthyroid healthy controls. Thyroid hormones, insulin, glucose, ghrelin levels and lipid parameters were measured in all subjects. Insulin sensitivity was determined using the homeostasis model assessment.

RESULTS

Serum ghrelin levels were significantly decreased in hyperthyroid patients than in controls (32.5 +/- 23.3 vs. 54.1 +/- 35.5 pg/ml, p < 0.001). Circulating ghrelin levels significantly correlated with age (r = -0.26, p = 0.01), fasting glucose (r = -0.21, p = 0.01), free triiodothyronine (r = -0.18, p = 0.04), free thyroxine (r = -0.23, p = 0.02) and thyroid stimulating hormone (r = 0.21, p = 0.04), but not with blood pressure, body mass index, lipid parameters, insulin and homeostasis model assessment (p > 0.05). Multiple regression analysis revealed glucose level to be the most important predictor of circulating ghrelin level.

CONCLUSION

These results indicate that hyperthyroidism has effect on serum ghrelin levels. Further studies are needed for the exact mechanism.

Adiponectin and its gene variants as risk factors for insulin resistance, the metabolic syndrome and cardiovascular disease

The increasing prevalence of obesity and metabolic syndrome/insulin resistance has attracted considerable interest due to their identification as risk factors for cardiovascular disease and, hence, targets for cardiovascular disease prevention. This review focuses on adiponectin, the most profusely secreted protein from adipose tissue, which itself is being increasingly recognised as an important and very active endocrine organ, secreting a wide range of biologically active substances known as adipokines or adipocytokines. Adiponectin has been demonstrated to have insulin sensitising effects, and secretion of adiponectin is reduced as adipose tissue mass increases. Adiponectin has also been demonstrated to have anti-inflammatory and anti-atherogenic properties, and is independently associated with cardiovascular disease. The evidence that suggests adiponectin plays a role in the relationship between obesity and insulin resistance, and also insulin resistance and cardiovascular disease, is examined. Variation in the adiponectin gene is one tool to determine whether this relationship is causal. The association of identified variants with human disease, specifically obesity and its consequences, type 2 diabetes and cardiovascular disease is reviewed. This data may enable patients at greater risk of the adverse effects of obesity to be identified and, as such, benefit from more targeted therapy of its consequences.

Angiotensin II infusion decreases plasma adiponectin level via its type 1 receptor in rats: an implication for hypertension-related insulin resistance

We explored the mechanisms underlying the close association between hypertension and insulin resistance by measuring the changes in the plasma levels of adiponectin, a novel insulin sensitizer secreted by adipose tissue, in rats infused with angiotensin II (AII). Angiotensin II (100 ng/kg per minute) was subcutaneously infused with osmotic minipumps for 2 weeks in rats fed with either standard chow or a high-fructose diet. Insulin sensitivity index (SI) was assessed by the minimal model of Bergman [Diabetes 1989;38:1512-27]. Angiotensin II infusion significantly increased blood pressure and decreased SI. Angiotensin II decreased plasma adiponectin levels from 3.7 to 2.9 microg/mL (P < .01) without affecting the expression of adiponectin messenger RNA in adipose tissue. Angiotensin II infusion did not affect plasma leptin and tumor necrosis factor alpha levels. An AII type 1 receptor blocker, olmesartan, restored the low adiponectinemia induced by the AII infusion (50 ng/kg per minute). Plasma adiponectin levels were significantly lower in fructose-fed rats (2.3 microg/mL) than in chow-fed rats. Angiotensin II induced no further decrease of adiponectin, whereas olmesartan increased adiponectin remarkably both with and without AII infusion. The AII type 2 receptor blocker PD123319 left the AII-induced hypoadiponectinemia unchanged in both chow- and fructose-fed rats. The AII type 2 receptor agonist CGP42112A also left the adiponectin unchanged. Plasma adiponectin levels were substantially correlated with SI (r = 0.61, P < .0001). These results suggest that AII suppresses adiponectin production via AII type 1 receptor, resulting in impaired insulin sensitivity.

Insulin resistance in postmenopausal women with metabolic syndrome and the measurements of adiponectin, leptin, resistin, and ghrelin

OBJECTIVE

Metabolic syndrome (MBS) is a significant health care problem in postmenopausal women and is driven largely by obesity. We wished to assess the prevalence of insulin resistance (IR), diagnosed using practical methods, and whether several adipocyte factors (adiponectin, leptin, resistin) or the gastric peptide ghrelin, associated with cardiovascular risk, might be abnormal and may relate to IR.

STUDY DESIGN

We evaluated 37 obese postmenopausal women with MBS and 34 matched obese premenopausal controls, as well as 14 non-obese premenopausal controls. We measured fasting glucose and insulin, performed 75 g 2 hr oral glucose tolerance and intravenous insulin tolerance tests to assess IR, and measured fasting lipids, adiponectin, leptin, resistin and ghrelin.

RESULTS

The kinetic decline in glucose after insulin (kITT) as a marker of IR was the most frequently abnormal test (abnormal in 81%), with QUICKI, HOMA, and a modification of the Matsuda-DeFronzo index (ISIM) abnormal in 76, 73, and 68%, respectively. The GIR was abnormal in only 35% of subjects. Leptin and resistin were elevated and adiponectin and ghrelin were decreased in the postmenopausal women, compared to both groups of premenopausal controls. BMI correlated strongly with markers of insulin resistance as well as adipocytokine values. After controlling for BMI, only leptin was predictive of ISIM.

CONCLUSION

Being overweight after menopause results in worsening IR and elevations in adipocytokine levels. While BMI is the most important factor, abnormal adipocytokine secretion may enhance IR and increase cardiovascular risk in postmenopausal women.

Ghrelin, adiponectin, and leptin do not predict long-term changes in weight and body mass index in older adults: longitudinal analysis of the Rancho Bernardo cohort

Ghrelin, leptin, and adiponectin are associated with body size in cross-sectional studies; it is unknown whether these hormones predict long-term changes in body size. Multilevel models were used to study associations between fasting serum hormones, measured in 698 men and 619 women (60-91 years) in samples collected at baseline (1984-1987), and changes in weight and body mass index, assessed repeatedly over a follow-up period of up to 18 years (median, 4.7 years). Baseline weight was -1.5 kg lower for a one-standard-deviation increment in ghrelin and -3.3 kg lower for a one-standard-deviation increment in adiponectin, similar in men and women. For leptin, baseline weight was 12.1 kg higher for a one-standard-deviation increment in men, compared with 5.7 kg in women (sex-interaction p < or = 0.0001). Ghrelin and adiponectin did not affect weight change; their associations with weight were constant over time, indicated by nonsignificant hormone-by-time interactions. The positive association between leptin and weight became slightly weaker over time. Results were similar when investigating repeated measures of body mass index. From this analysis of Rancho Bernardo Study data, the authors conclude that ghrelin, adiponectin, and leptin do not predict weight gain beyond reflecting the influence of attained body size on future changes in weight or body mass index.

Determinants of Circulating Adiponectin in Women with Polycystic Ovary Syndrome

BACKGROUND AND AIM

Adiponectin is regarded as a possible link between adiposity and insulin resistance. Ghrelin and leptin are considered as signals of energy status. We evaluated the relationships between these peptides, androgens and insulin sensitivity in women affected by polycystic ovary syndrome.

METHODS

Thirty-six women with PCOS were examined with euglycemic hyperinsulinemic clamp (to determine M/I, index of insulin sensitivity). Leptin, ghrelin, adiponectin, androgens, and SHBG were determined. Statistics was done using correlation analysis and backward stepwise multiple regression.

RESULTS

The positive correlation of adiponectin with testosterone remains significant even after adjustment for BMI (p = 0.01), M/I (p = 0.009) and for both M/I and BMI (p = 0.02). In multiple regression with testosterone, M/I, leptin and ghrelin as independent variables, the model including testosterone (p = 0.03) and ghrelin (p = 0.002) explained 49% of the variability (p < 0.0012) of adiponectin.

CONCLUSIONS

Both adiponectin and ghrelin can be involved in the pathophysiology of PCOS but their relation must be delineated further.

Decreased circulating levels of active ghrelin are associated with increased oxidative stress in obese subjects

OBJECTIVE

To investigate the relationship between active ghrelin and oxidative stress in obese subjects.

DESIGN

We measured the plasma levels of free 8-epi-prostaglandin F(2alpha) (8-epi-PGF(2alpha), a reliable and systemic marker of oxidative stress) and the active form of ghrelin in 17 obese and 17 normal subjects. The biologically active forms of ghrelin were measured using a commercially available radio-immunoassay kit and free 8-epi-PGF(2alpha) was measured using an enzyme immunoassay kit.

RESULTS

The circulating level of active ghrelin was significantly decreased (20.4 +/- 2.6 vs 40.9 +/- 3.9 fmol/ml, P < 0.01) while that of 8-epi-PGF(2alpha) was significantly increased (61.5 +/- 9.6 vs 17.3 +/- 3.4 pg/ml, P < 0.01) in obese subjects compared with normal subjects. The plasma levels of active ghrelin and 8-epi-PGF(2alpha) were significantly correlated in obese (r = -0.507, P < 0.05) and in all (r = -0.577, P < 0.01) subjects. Multivariate analysis showed that the plasma levels of active ghrelin and 8-epi-PGF(2alpha) were significantly and independently correlated in all subjects (F = 7.888, P < 0.01).

CONCLUSIONS

There is an inverse correlation between circulating levels of active ghrelin and oxidative stress in obesity. Low circulating levels of active ghrelin may enhance oxidative stress and the process of atherosclerosis in obese subjects.

Abdominal adipose tissue cytokine gene expression: relationship to obesity and metabolic risk factors

Adipose tissue is a major source of inflammatory and thrombotic cytokines. This study investigated the relationship of abdominal subcutaneous adipose tissue cytokine gene expression to body composition, fat distribution, and metabolic risk during obesity. We determined body composition, abdominal fat distribution, plasma lipids, and abdominal subcutaneous fat gene expression of leptin, TNF-alpha, IL-6, PAI-1, and adiponectin in 20 obese, middle-aged women (BMI, 32.7 +/- 0.8 kg/m2; age, 57 +/- 1 yr). A subset of these women without diabetes (n = 15) also underwent an OGTT. In all women, visceral fat volume was negatively related to leptin (r = -0.46, P < 0.05) and tended to be negatively related to adiponectin (r = -0.38, P = 0.09) gene expression. Among the nondiabetic women, fasting insulin (r = 0.69, P < 0.01), 2-h insulin (r = 0.56, P < 0.05), and HOMA index (r = 0.59, P < 0.05) correlated positively with TNF-alpha gene expression; fasting insulin (r = 0.54, P < 0.05) was positively related to, and 2-h insulin (r = 0.49, P = 0.06) tended to be positively related to, IL-6 gene expression; and glucose area (r = -0.56, P < 0.05) was negatively related to, and insulin area (r = -0.49, P = 0.06) tended to be negatively related to, adiponectin gene expression. Also, adiponectin gene expression was significantly lower in women with vs. without the metabolic syndrome (adiponectin-beta-actin ratio, 2.26 +/- 0.46 vs. 3.31 +/- 0.33, P < 0.05). We conclude that abdominal subcutaneous adipose tissue expression of inflammatory cytokines is a potential mechanism linking obesity with its metabolic comorbidities.

Preprandial ghrelin is not affected by macronutrient intake, energy intake or energy expenditure

Background

Ghrelin, a peptide secreted by endocrine cells in the gastrointestinal tract, is a hormone purported to have a significant effect on food intake and energy balance in humans. The influence of factors related to energy balance on ghrelin, such as daily energy expenditure, energy intake, and macronutrient intake, have not been reported. Secondly, the effect of ghrelin on food intake has not been quantified under free-living conditions over a prolonged period of time. To investigate these effects, 12 men were provided with an ad libitum cafeteria-style diet for 16 weeks. The macronutrient composition of the diets were covertly modified with drinks containing 2.1 MJ of predominantly carbohydrate (Hi-CHO), protein (Hi-PRO), or fat (Hi-FAT). Total energy expenditure was measured for seven days on two separate occasions (doubly labeled water and physical activity logs).

Results

Preprandial ghrelin concentrations were not affected by macronutrient intake, energy expenditure or energy intake (all P > 0.05). In turn, daily energy intake was significantly influenced by energy expenditure, but not ghrelin.

Conclusion

Preprandial ghrelin does not appear to be influenced by macronutrient composition, energy intake, or energy expenditure. Similarly, ghrelin does not appear to affect acute or chronic energy intake under free-living conditions.

Inflammation, insulin resistance, and obesity

Obesity, in particular visceral obesity, has strong associations with cardiovascular disease and is related to many factors that are constituents of the metabolic syndrome. Increasing evidence suggests that features of the metabolic syndrome, including visceral obesity, are associated with a low-grade inflammatory state. Indeed, visceral fat is a source of several molecules, such as leptin, adiponectin, tumor necrosis factor-alpha, and interleukin 6, that are collectively called adipokines. All of them may induce a proinflammatory state and oxidative damage, leading to initiation and progression of atherosclerosis. Reduced-energy diets might represent an effective and healthful approach for long-term weight loss in patients with metabolic syndrome by reducing the underlying inflammatory condition.

Serum concentrations of leptin, adiponectin and resistin, and their relationship with cardiovascular disease in patients with end-stage renal disease

BACKGROUND AND OBJECTIVE

High levels of some adipocytokines have been reported in patients with chronic renal failure, but little information is available on adipocytokine concentrations in uraemic patients under different modalities of therapy. Our aims were (1) to quantify the serum concentrations of leptin, adiponectin and resistin in uraemic patients on peritoneal dialysis (PD) and haemodialysis (HD), in comparison with patients on conservative management, and (2) to study the relationships between adipocytokine levels and previous atherosclerotic vascular disease.

PATIENTS AND MEASUREMENTS

We studied 82 dialysis patients treated by PD (n = 44, 23 males and 21 females, mean age 54.4 +/- 1.8 years) or HD (n = 38, 22 males and 16 females, age 60.8 +/- 1.6 years). A group of 19 uraemic patients on conservative management served as the control. Serum concentrations of leptin, adiponectin and resistin were measured in all subjects. Information on vascular disease (cerebral vascular, peripheral vascular and heart disease) was obtained from a detailed medical history.

RESULTS

PD patients showed significantly higher serum leptin concentrations [median (interquartile range), 28.7 (13.0-71.9) microg/l] than those found in patients on HD [9.7 (4.7-31.9) microg/l, P < 0.01] or in conservative management [5.9 (4.3-38.6) microg/l, P < 0.05]. Adiponectin concentrations were similar in the three groups of patients (mean +/- SEM, 48.0 +/- 4.5 mg/l in PD, 57.7 +/- 4.4 mg/l in HD, and 44.4 +/- 7.0 mg/l in controls, NS). Patients treated by both PD and HD exhibited resistin concentrations significantly higher than those found in controls (26.3 +/- 0.99 and 27.5 +/- 1.4 microg/l, respectively, vs. 17.3 +/- 1.0 microg/l, P < 0.001). Leptin concentrations were positively correlated with body mass index (BMI) (r = 0.287, P < 0.01) and adiponectin levels were negatively related to BMI (r = -0.416, P < 0.001) and the homeostatic model assessment (HOMA-R) index (r =-0.216, P < 0.05). Leptin, adiponectin and resistin levels in patients with previous vascular events were similar to those found in patients without these complications. Logistic regression analysis did not demonstrate any relationship between serum adipocytokine concentrations and the presence of vascular disease of any type. A significant relationship between resistin and heart disease [odds ratio (OR) 1.80 (1.03-3.15), P = 0.039] was found when analysing subgroups of patients.

CONCLUSIONS

These data suggest that leptin levels are higher in PD patients, and resistin levels are higher in PD and HD patients in relation to patients on conservative management, whereas adiponectin concentrations are similar in the three groups. These results do not support the presence of a clinically relevant relationship between adipocytokines and previous episodes of vascular disease in the whole population or in patients classified in subgroups, with the only exception of a relationship between resistin levels and heart disease.