Circulating adiponectin levels are reduced in nonobese but insulin-resistant first-degree relatives of type 2 diabetic patients

Evaluation of Adiponectin and ANGPTL8 in Women With Metabolic Syndrome in the Madinah Region of Saudi Arabia

OBJECTIVE

 "Metabolic syndrome" (MetS) is a set of abnormalities that may be risk factors for cardiovascular disease (CVD) and diabetes. The current study sought to (1) determine MetS prevalence and (2) examine Adiponectin and ANGPTL8 levels in connection to MetS components and CVDs and diabetes risk in females with MetS.

METHODS

A total of 350, 20-35-year-old Saudi females were studied. Waist circumference (WC), body mass index (BMI), glucose, HbA1c, insulin, lipid profiles, and blood pressure (BP) were examined for MetS. ANGPTL8 and Adiponectin were also measured.

RESULTS

The patients were classified into two groups, namely MetS and non-MetS, according to the criteria established by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII). We examined biomarker and anthropometric results between these groups. One hundred forty-four of 350 female participants (41.2%) had MetS, with a mean age of 30.5 years. Fasting blood glucose (FBG), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), ANGPTL8, adiponectin, and insulin resistance (IR) were statistically significant differences observed between the two groups. BP, BMI, WC, and Atherogenic Index of Plasma (AIP) all changed significantly (P ≤0.05). Correlation studies linked MetS components to higher ANGPTL-8 and reduced adiponectin. The levels of ANGPTL8 were shown to be influenced by the increase in FBG, TG, BP, IR, and AIP (P < 0.05). Factors such as FBG, BMI, WC, and IR have been found to have an inverse relationship with adiponectin levels.

CONCLUSION

41.2% out of 350 Saudi females at Taibah University in the Madinah region had MetS, medium CVD risk, and slightly elevated BMI, TG, WC, and BP. To lower their risk of CVD and diabetes later in life, overweight young women should be evaluated for MetS. FBG and TG were substantially associated with ANGPTL8 while reducing adiponectin was associated with elevated TG and BP. Our findings may lead to ANGPTL8 and adiponectin's possible predictive function for CVD in early MetS in females.

Serum Orosomucoid Is Associated with Serum Adiponectin, Adipose Tissue Insulin Resistance Index, and a Family History of Type 2 Diabetes in Young Normal Weight Japanese Women

INTRODUCTION

Adipose tissue (AT) expandability may be facilitated by adiponectin and suppressed by orosomucoid, and reduced AT expandability may be associated with first-degree relatives of type 2 diabetes. We tested the hypothesis that orosomucoid may be associated not only with adiponectin and adipose tissue insulin resistance but also with a family history of type 2 diabetes (FHD). Research Design and Methods. Anthropometric and metabolic variables, adipokines, and measures of inflammatory and insulin resistance were cross-sectionally investigated in 153 young normal weight Japanese women. Stepwise multivariate linear regression analyses were used to identify the most important determinants of orosomucoid.

RESULTS

Orosomucoid was higher in women with positive (n = 57) compared to women with negative FHD and was associated positively with FHD (both p = 0.01). Orosomucoid also showed positive associations with fasting glucose (p < 0.001), free fatty acids (p = 0.001), and HbA1c (p = 0.007), whereas there was no association with fasting insulin and serum lipids. In addition, orosomucoid was associated inversely with adiponectin (p = 0.02) and positively with adipose tissue-insulin resistance index (AT-IR, the product of fasting insulin and free fatty acids; p = 0.001) but not with homeostasis model assessment-insulin resistance, leptin, and high-sensitivity C-reactive protein. In multivariate analyses, AT-IR (standardized β, 0.22; p = 0.003), serum adiponectin (standardized β, -0.163; p = 0.032), FHD+ (standardized β, 0.178; p = 0.029), and HbA1c (standardized β, 0.213; p = 0.005) emerged as independent determinants of orosomucoid and explained 15.2% of its variability.

CONCLUSIONS

These results are the first to demonstrate that orosomucoid is associated not only with adipose tissue-insulin resistance and adiponectin but also with FHD.

Beneficial Effects of Resveratrol in Mouse Gastrocnemius: A Hint to Muscle Phenotype and Proteolysis

We hypothesized that the phenolic compound resveratrol mitigates muscle protein degradation and loss and improves muscle fiber cross-sectional area (CSA) in gastrocnemius of mice exposed to unloading (7dI). In gastrocnemius of mice (female C57BL/6J, 10 weeks) exposed to a seven-day period of hindlimb immobilization with/without resveratrol treatment, markers of muscle proteolysis (tyrosine release, systemic troponin-I), atrophy signaling pathways, and muscle phenotypic features and function were analyzed. In gastrocnemius of unloaded mice treated with resveratrol, body and muscle weight and function were attenuated, whereas muscle proteolysis (tyrosine release), proteolytic and apoptotic markers, atrophy signaling pathways, and myofiber CSA significantly improved. Resveratrol treatment of mice exposed to a seven-day period of unloading prevented body and muscle weight and limb strength loss, while an improvement in muscle proteolysis, proteolytic markers, atrophy signaling pathways, apoptosis, and muscle fiber CSA was observed in the gastrocnemius muscle. These findings may have potential therapeutic implications in the management of disuse muscle atrophy in clinical settings.

Adipokine and fat body in flies: Connecting organs

Under conditions of nutritional and environmental stress, organismal homeostasis is preserved through inter-communication between multiple organs. To do so, higher organisms have developed a system of interorgan communication through which one tissue can affect the metabolism, activity or fate of remote organs, tissues or cells. In this review, we discuss the latest findings emphasizing Drosophila melanogaster as a powerful model organism to study these interactions and may constitute one of the best documented examples depicting the long-distance communication between organs. In flies, the adipose tissue appears to be one of the main organizing centers for the regulation of insect development and behavior: it senses nutritional and hormonal signals and in turn, orchestrates the release of appropriate adipokines. We discuss the nature and the role of recently uncovered adipokines, their regulations by external cues, their secretory routes and their modes of action to adjust developmental growth and timing accordingly. These findings have the potential for identification of candidate factors and signaling pathways that mediate conserved interorgan crosstalk.

Hormonal Dysregulation and Unbalanced Specialized Pro-Resolving Mediator Biosynthesis Contribute toward Impaired B Cell Outcomes in Obesity

Diet-induced obesity is associated with impaired B-cell-driven humoral immunity, which coincides with chronic inflammation and has consequences for responses to infections and vaccinations. Key nutritional, cellular, and molecular mechanisms by which obesity may impair aspects of humoral immunity such as B cell development, class switch recombination, and formation of long-lived antibody secreting cells are reviewed. A key theme to emerge is the central role of white adipose tissue on the formation and function of pro-inflammatory B cell subsets that exacerbate insulin resistance. The underlying role of select hormones such as leptin is highlighted, which may be driving the formation of pro-inflammatory B cells in the absence of antigen stimulation. This review also extensively covers the regulatory role of lipid metabolites such as prostaglandins and specialized pro-resolving mediators (SPMs) that are synthesized from polyunsaturated fatty acids. Notably, SPM biosynthesis is impaired in obesity and contributes toward impaired antibody production. Future directions for research, including avenues for therapeutic intervention, are included.

Influence of macronutrient composition of commercial diets on circulating leptin and adiponectin concentrations in overweight dogs

Leptin and adiponectin play important roles in obesity‐related inflammation and comorbidities. Previous research suggests that alterations in dietary macronutrient composition can modify circulating leptin and adiponectin concentrations in people, but limited research on this subject has been performed in dogs. This study investigated the effects of commercial high protein (HP), high fat (HF) and high carbohydrate medium protein (HCMP) diets on baseline (T₋₁) concentrations, post‐prandial peak concentrations and total release in a ten‐hour time span of leptin and adiponectin in dogs, when compared to a maintenance high carbohydrate low protein (HCLP) diet. Thirty‐six overweight dogs were fed the HCLP diet in a one‐week control period, after which the animals were assigned to one of three groups. In three four‐week periods, each group was fed all test diets in a different sequence. At the last day of each period, blood was sampled at one hour before feeding (T₋₁) and at three (T₃), six (T₆) and nine (T₉) hours after feeding. Feeding caused peak leptin concentrations at T₆ and T₉ (p < .001). No significant post‐prandial change in adiponectin concentrations was found (p = .056). The HP diet resulted in lower leptin peak concentrations (p = .004) and AUC_T−1–T9 (p = .01), but none of the diets influenced baseline leptin concentrations (p = .273). Baseline adiponectin concentrations were lower for the HF diet (p = .018) and HCMP (p < .001), and the HP, HF and HCMP AUC_T−1–T9 (p < .001) were lower compared with the HCLP diet. Female dogs had lower adiponectin baseline concentrations (p = .041) and AUC_T−1–T9 (p = .023) than male dogs. In conclusion, the HP diet was associated with the lowest post‐prandial peak leptin concentration and the least decrease in adiponectin release, suggesting that a HP diet may improve immune‐metabolic health and post‐prandial satiety in overweight dogs.

Resveratrol regulates skeletal muscle fibers switching through the AdipoR1-AMPK-PGC-1α pathway

This study was conducted to investigate the effect and underlying mechanism of Resveratrol (RES) in regulating skeletal muscle fiber-type switching.

Clinical Applications of Adiponectin Measurements in Type 2 Diabetes Mellitus: Screening, Diagnosis, and Marker of Diabetes Control

Background

Adipose tissue-derived adiponectin has pleiotropic protective effects with suppression of inflammatory and metabolic derangements that may result in insulin resistance, metabolic syndrome, type 2 diabetes mellitus (T2DM), and cardiovascular disease. The aim of this study was to evaluate adiponectin as a diagnostic marker of T2DM and diabetes control.

Methods

Fasting adiponectin, insulin, glucose, and HbA1c were determined in 376 patients with known T2DM and 575 subjects with undiagnosed diabetes but with family history of T2DM. Clinical and anthropometric data were recorded. Subjects were classified on the basis of degree of adiposity, insulin resistance (IR), and achievement of target HbA1c levels. Receiver operating characteristic (ROC) curve analysis was used to examine the diagnostic performance for undiagnosed DM.

Results

In undiagnosed subjects, adiponectin was significantly lower in subjects with IR and diabetic subjects compared with those without. The area under the adiponectin ROC curve for diagnosis of DM was 0.740. In known T2DM subjects, those with good control had significantly higher adiponectin (8.6 versus 7.4 μg/mL) compared to subjects with poor control.

Conclusions

Adiponectin levels are associated with better glycemic control and could be a useful adjunct for screening for IR and T2DM. Therapeutic measures that increase adiponectin levels might be valuable targets for improving diabetes control and decreasing complications.

Arachidonic acid in health and disease with focus on hypertension and diabetes mellitus: A review

Arachidonic acid (AA 20:4n-6) is an essential component of cell membranes and modulates cell membrane fluidity. AA is metabolized by cyclo-oxygenase (COX), lipoxygenase (LOX) and cytochrome P450 enzymes to form several metabolites that have important biological actions. Of all the actions, role of AA in the regulation of blood pressure and its ability to prevent both type 1 and type 2 diabetes mellitus seems to be interesting. Studies showed that AA and its metabolites especially, lipoxin A4 (LXA4) and epoxyeicosatrienoic acids (EETs), potent anti-inflammatory metabolites, have a crucial role in the pathobiology of hypertension and diabetes mellitus. AA, LXA4 and EETs regulate smooth muscle function and proliferation, voltage gated ion channels, cell membrane fluidity, membrane receptors, G-coupled receptors, PPARs, free radical generation, nitric oxide formation, inflammation, and immune responses that, in turn, participate in the regulation blood pressure and pathogenesis of diabetes mellitus. In this review, role of AA and its metabolites LXA4 and EETs in the pathobiology of hypertension, pre-eclampsia and diabetes mellitus are discussed. Based on several lines of evidences, it is proposed that a combination of aspirin and AA could be of benefit in the prevention and management of hypertension, pre-eclampsia and diabetes mellitus.

Is There a Role for Bioactive Lipids in the Pathobiology of Diabetes Mellitus?

Inflammation, decreased levels of circulating endothelial nitric oxide (eNO) and brain-derived neurotrophic factor (BDNF), altered activity of hypothalamic neurotransmitters (including serotonin and vagal tone) and gut hormones, increased concentrations of free radicals, and imbalance in the levels of bioactive lipids and their pro- and anti-inflammatory metabolites have been suggested to play a role in diabetes mellitus (DM). Type 1 diabetes mellitus (type 1 DM) is due to autoimmune destruction of pancreatic β cells because of enhanced production of IL-6 and tumor necrosis factor-α (TNF-α) and other pro-inflammatory cytokines released by immunocytes infiltrating the pancreas in response to unknown exogenous and endogenous toxin(s). On the other hand, type 2 DM is due to increased peripheral insulin resistance secondary to enhanced production of IL-6 and TNF-α in response to high-fat and/or calorie-rich diet (rich in saturated and trans fats). Type 2 DM is also associated with significant alterations in the production and action of hypothalamic neurotransmitters, eNO, BDNF, free radicals, gut hormones, and vagus nerve activity. Thus, type 1 DM is because of excess production of pro-inflammatory cytokines close to β cells, whereas type 2 DM is due to excess of pro-inflammatory cytokines in the systemic circulation. Hence, methods designed to suppress excess production of pro-inflammatory cytokines may form a new approach to prevent both type 1 and type 2 DM. Roux-en-Y gastric bypass and similar surgeries ameliorate type 2 DM, partly by restoring to normal: gut hormones, hypothalamic neurotransmitters, eNO, vagal activity, gut microbiota, bioactive lipids, BDNF production in the gut and hypothalamus, concentrations of cytokines and free radicals that results in resetting glucose-stimulated insulin production by pancreatic β cells. Our recent studies suggested that bioactive lipids, such as arachidonic acid, eicosapentaneoic acid, and docosahexaenoic acid (which are unsaturated fatty acids) and their anti-inflammatory metabolites: lipoxin A4, resolvins, protectins, and maresins, may have antidiabetic actions. These bioactive lipids have anti-inflammatory actions, enhance eNO, BDNF production, restore hypothalamic dysfunction, enhance vagal tone, modulate production and action of ghrelin, leptin and adiponectin, and influence gut microbiota that may explain their antidiabetic action. These pieces of evidence suggest that methods designed to selectively deliver bioactive lipids to pancreatic β cells, gut, liver, and muscle may prevent type 1 and type 2 DM.

Circulating and Adipose Levels of Adipokines Associated With Insulin Sensitivity in Nonobese Subjects With Type 2 Diabetes

CONTEXT

The adipokines chemerin, dipeptidyl peptidase 4, and adiponectin influence insulin sensitivity. Whether their circulating levels and adipose secretion are altered in nonobese individuals with type 2 diabetes mellitus (T2DM) is unknown.

OBJECTIVE

The objective of this study was to investigate SC adipose secretion and serum levels of the three adipokines in relation to T2DM features.

DESIGN

Fourteen nonobese T2DM and 13 healthy men were investigated. Insulin sensitivity and glucose control were assessed by hyperinsulinemic euglycemic clamp, homeostasis model assessment, and glycated hemoglobin.

MAIN OUTCOME MEASURE

Association of circulating and adipose-secreted adipokines with fat cell volume and insulin sensitivity was measured.

PARTICIPANTS

Volunteers in an outpatient academic clinic participated.

RESULTS

Although adipose secretion was similar between the groups, serum chemerin was higher (70 ± 10 vs 50 ± 1 ng/ml; P = .005), adiponectin lower (4.7 ± 1.3 vs 6.8 ± 2.2 μg/ml; P = .005), and dipeptidyl peptidase 4 unaltered in T2DM. Serum adiponectin (r = 0.53; P = .005) and chemerin (r = -0.42; P = .03) correlated with adipose secreted levels. Secreted and circulating chemerin correlated positively with adipocyte volume (r > 0.40; P < .05), whereas serum adiponectin correlated negatively with this measure (r = -0.61; P = .001). Adiponectin serum half-life was decreased in T2DM (168 ± 24 vs 186 ± 18 minutes; P = .029) and correlated negatively with glycated hemoglobin (r = -0.45; P = .03) and adipocyte volume (r = -0.56; P < .003). Serum adiponectin (r = 0.57; P = .017) and chemerin (r = -0.52; P = .03) associated with clamp measures independently of T2DM diagnosis.

CONCLUSIONS

In nonobese men, circulating adiponectin and chemerin levels are altered in T2DM without changes in adipose secretion. Adipocyte volume is important for variations in serum chemerin and adiponectin and for serum clearance of adiponectin. In T2DM, poor glucose control also plays a role for adiponectin clearance.

Adiponectin Levels in Women With Polycystic Ovary Syndrome and Severe Insulin Resistance

OBJECTIVE

Adiponectin is an adipokine that is decreased in obesity and type 2 diabetes. Women with polycystic ovarian syndrome (PCOS) are obese and are at risk for type 2 diabetes. The objective of the current study was to investigate the relationship of adiponectin to obesity and insulin resistance in women with PCOS and severe insulin resistance.

METHODS

Thirty women with PCOS and acanthosis nigricans indicating severe insulin resistance were included in the study. Eleven body mass index (BMI)-matched women with normal ovulatory cycles served as controls. Fasting glucose, insulin, and adiponectin levels were measured, and a standard oral glucose tolerance test (OGTT) with insulin levels was performed. To further investigate the role of insulin sensitivity on adiponectin levels, 10 women with PCOS were treated with 4 mg rosiglitazone daily for 6 months and adiponectin levels were measured before and after treatment.

RESULTS

Fasting insulin levels (33.5 +/- 3.8 microU/mL; P <.001) and insulin area under the curve (AUC) during OGTT (536.2 +/- 70.5 microU/mL; P <.01) were higher in women with PCOS, while glucose levels were similar to controls. Adiponectin levels were lower (P <.01) in women with PCOS (5.6 +/- 2.6 microg/mL) compared with controls (8.5 +/- 3.9 microg/mL). There was a significant negative correlation between adiponectin levels and fasting insulin levels (r = -0.40, P = .02), insulin AUC during OGTT (r = -0.47, P = .008), fasting glucose levels (r = -0.45, P = .01), and glucose AUC during OGTT (r = -0.51, P = .003). There was no correlation between BMI and serum adiponectin (r = -0.12, P = .508) in women with PCOS, while there was a negative correlation (r = -0.746, P = .013) in controls. There was a significant (P <.01) increase in adiponectin levels when treated with rosiglitazone, despite unchanged BMI.

CONCLUSION

These results indicate that in women with PCOS and severe insulin resistance, insulin sensitivity appears to be the major determinant of adiponectin levels rather than adiposity. Low adiponectin levels may predict women with PCOS who are at high risk for developing type 2 diabetes.

Adipocyte hypertrophy, inflammation and fibrosis characterize subcutaneous adipose tissue of healthy, non-obese subjects predisposed to type 2 diabetes

Background

The adipose tissue is important for development of insulin resistance and type 2 diabetes and adipose tissue dysfunction has been proposed as an underlying cause. In the present study we investigated presence of adipocyte hypertrophy, and gene expression pattern of adipose tissue dysfunction in the subcutaneous adipose tissue of healthy, non-obese subjects predisposed to type 2 diabetes compared to matched control subjects with no known genetic predisposition for type 2 diabetes.

Method

Seventeen healthy and non-obese subjects with known genetic predisposition for type 2 diabetes (first-degree relatives, FDRs) and 17 control subjects were recruited. The groups were matched for gender and BMI and had similar age. Glucose tolerance was determined by an oral glucose tolerance test and insulin sensitivity was calculated using HOMA-index. Blood samples were collected and subcutaneous abdominal adipose tissue biopsies obtained for gene expression analysis and adipocyte cell size measurement.

Results

Our findings show that, in spite of similar age, BMI and percent body fat, FDRs displayed adipocyte hypertrophy, as well as higher waist/hip ratio, fasting insulin levels, HOMA-IR and serum triglycerides. Adipocyte hypertrophy in the FDR group, but not among controls, was associated with measures of impaired insulin sensitivity. The adipocyte hypertrophy was accompanied by increased inflammation and Wnt-signal activation. In addition, signs of tissue remodeling and fibrosis were observed indicating presence of early alterations associated with adipose tissue dysfunction in the FDRs.

Conclusion

Genetic predisposition for type 2 diabetes is associated with impaired insulin sensitivity, adipocyte hypertrophy and other markers of adipose tissue dysfunction. A dysregulated subcutaneous adipose tissue may be a major susceptibility factor for later development of type 2 diabetes.

Adiponectin and energy homeostasis

White adipose tissue (WAT) is the premier energy depot. Since the discovery of the hormonal properties of adipose-secreted proteins such as leptin and adiponectin, WAT has been classified as an endocrine organ. Although many regulatory effects of the adipocyte-derived hormones on various biological systems have been identified, maintaining systemic energy homeostasis is still the essential function of most adipocyte-derived hormones. Adiponectin is one adipocyte-derived hormone and well known for its effect in improving insulin sensitivity in liver and skeletal muscle. Unlike most other adipocyte-derived hormones, adiponectin gene expression and blood concentration are inversely associated with adiposity. Interestingly, recent studies have demonstrated that, in addition to its insulin sensitizing effects, adiponectin plays an important role in maintaining energy homeostasis. In this review, we summarize the progress of research about 1) the causal relationship of adiposity, energy intake, and adiponectin gene expression; and 2) the regulatory role of adiponectin in systemic energy metabolism.

Metabolic syndrome and insulin resistance: underlying causes and modification by exercise training

Metabolic syndrome (MS) is a collection of cardiometabolic risk factors that includes obesity, insulin resistance, hypertension, and dyslipidemia. Although there has been significant debate regarding the criteria and concept of the syndrome, this clustering of risk factors is unequivocally linked to an increased risk of developing type 2 diabetes and cardiovascular disease. Regardless of the true definition, based on current population estimates, nearly 100 million have MS. It is often characterized by insulin resistance, which some have suggested is a major underpinning link between physical inactivity and MS. The purpose of this review is to: (i) provide an overview of the history, causes and clinical aspects of MS, (ii) review the molecular mechanisms of insulin action and the causes of insulin resistance, and (iii) discuss the epidemiological and intervention data on the effects of exercise on MS and insulin sensitivity.

Short-term overfeeding increases circulating adiponectin independent of obesity status

Background

Adiponectin is an adipose tissue derived hormone which strengthens insulin sensitivity. However, there is little data available regarding the influence of a positive energy challenge (PEC) on circulating adiponectin and the role of obesity status on this response.

Objective

The purpose of this study was to investigate how circulating adiponectin will respond to a short-term PEC and whether or not this response will differ among normal-weight(NW), overweight(OW) and obese(OB).

Design

We examined adiponectin among 64 young men (19-29 yr) before and after a 7-day overfeeding (70% above normal energy requirements). The relationship between adiponectin and obesity related phenotypes including; weight, percent body fat (%BF), percent trunk fat (%TF), percent android fat (%AF), body mass index (BMI), total cholesterol, HDLc, LDLc, glucose, insulin, homeostatic model assessment insulin resistance (HOMA-IR) and β-cell function (HOMA-β) were analyzed before and after overfeeding.

Results

Analysis of variance (ANOVA) and partial correlations were used to compute the effect of overfeeding on adiponectin and its association with adiposity measurements, respectively. Circulating Adiponectin levels significantly increased after the 7-day overfeeding in all three adiposity groups. Moreover, adiponectin at baseline was not significantly different among NW, OW and OB subjects defined by either %BF or BMI. Baseline adiponectin was negatively correlated with weight and BMI for the entire cohort and %TF, glucose, insulin and HOMA-IR in OB. However, after controlling for insulin resistance the correlation of adiponectin with weight, BMI and %TF were nullified.

Conclusion

Our study provides evidence that the protective response of adiponectin is preserved during a PEC regardless of adiposity. Baseline adiponectin level is not directly associated with obesity status and weight gain in response to short-term overfeeding. However, the significant increase of adiponectin in response to overfeeding indicates the physiological potential for adiponectin to attenuate insulin resistance during the development of obesity.

Small, dense LDL particles predict changes in intima media thickness and insulin resistance in men with type 2 diabetes and prediabetes--a prospective cohort study

The association of small, dense low-density lipoprotein (sdLDL) particles with an increased cardiovascular risk is well established. However, its predictive value with regard to glucose metabolism and arterial disease in patients with type 2 diabetes has not been thoroughly investigated. We conducted a prospective longitudinal cohort study in patients with (pre)diabetes who were seen at baseline and after two years. sdLDL particles were determined by gradient gel electrophoresis. Insulin resistance was estimated by using the homeostatic model assessment 2 (HOMA2). Intima media thickness (IMT) and flow-mediated dilation (FMD) were assessed by ultrasound measurements. Fifty-nine patients (mean age 63.0 ± 12.2 years) were enrolled and 39 were seen at follow-up. IMT increased in the whole cohort during follow-up. The change in IMT was predicted by the proportion of sdLDL particles at baseline (p=0.03), and the change in FMD was predicted by LDL-cholesterol levels at baseline (p=0.049). HOMA2 and changes in HOMA2 correlated with the proportion of sdLDL particles and changes in this proportion, respectively (p<0.05 for both). Serum resistin levels increased in parallel with the increasing sdLDL particle number, while serum adiponectin increased only in patients with unaltered sdLDL particle number at follow-up (p<0.01 for both). In conclusion, the proportion of small, dense LDL particles and changes in this proportion are predictive of changes in intima media thickness and insulin resistance, and are closely associated with other determinants of an adverse metabolic status. Thus, this parameter extends the individual risk assessment beyond the limitations of traditional risk markers in patients with dysglycemia.

Adiponectin and its receptors in chronic hepatitis B patients with steatosis in china

BACKGROUND

HBV infection is a serious public health problem worldwide, which can contribute to the incidence of chronic hepatitis B (CHB), cirrhosis, and hepatocellular carcinoma (HCC).

OBJECTIVES

In the present report, we assessed the association between adiponectin, its receptors and hepatic steatosis, fibrosis, and inflammation with hepatitis B virus.

PATIENTS AND METHODS

Liver biopsies from 89 patients with untreated chronic hepatitis B (34 steatosis vs. 55 without steatosis) were analyzed; liver biopsies from 50 healthy adults were used as control. The liver biopsies were subjected to routine histological examination, and stained immunohistochemically for adiponectin and adiponectin receptor2 (adipoR2).

RESULTS

The two groups were found to be comparable with respect to demographic, biochemical, metabolic, histological, and viral characteristics. BMI, γ-GT, FPG, insulin, and insulin sensitivity estimated by the HOMA index were significantly higher in patients with steatosis. The viral load of HBV and HBeAg positivity was higher in patients with steatosis than those without steatosis. High serum adiponectin levels were significantly correlated with abnormal serum ALT level (vs. normal ALT, P = 0.000), and HBV genotype C (vs. genotype B, P = 0.018). In patients with chronic HBV, the insulin sensitizing adipokine adiponectin, and its receptor AdipoR2were associated with steatosis. While adiponectin may becorrelated with inflammation, adiponectin, and its receptors were not associated with viral factors.

CONCLUSIONS

Our results suggest that the role of adiponectin might be impaired in chronic hepatitis B with steatosis. Reduced hepatic expression of adiponectin and adipoR2 might be of pathophysiological relevance in CHB patients with steatosis. These findings indicated that reduced liver adiponectin expression may play an important role in the pathogenesis, and progression of CHB patients with steatosis. However, hepatic expression of adiponectin, and adipoR2 was not associated with various measures of HBV infection.

Daily flaxseed consumption improves glycemic control in obese men and women with pre-diabetes: a randomized study

The study hypothesis was that fasting glucose, insulin, fructosamine, C-reactive protein, and interleukin-6 decrease and adiponectin increases with daily flaxseed consumption in overweight or obese individuals with pre-diabetes. In this randomized, cross-over study overweight or obese men and postmenopausal women (n = 25) with pre-diabetes consumed 0, 13, or 26 g ground flaxseed for 12 weeks. Glucose, insulin, homeostatic model assessment (HOMA-IR), and normalized percent of α-linolenic fatty acid (ALA) were significantly different by treatment (multiple analysis of variance, P = .036, P = .013, P = .008, P = .024 respectively). Paired t tests showed glucose decreased on the 13 g intervention compared to the 0 g period [13 g = -2.10 ± 1.66 mg/L (mean ± SEM), 0 g = 9.22 ± 4.44 mg/L, P = .036]. Insulin decreased on the 13 g intervention but not the 26 g (P = .021) and 0 g (P = .013) periods (13 g = -2.12 ± 1.00 mU/L, 26 g = 0.67 ± 0.84 mU/L, 0 g = 1.20 ± 1.16 mU/L). HOMA-IR decreased on the 13 g period but not on the 26 g (P = .012) and 0 g (P = .008) periods (13 g = -0.71 ± 0.31, 26 g = 0.27 ± 0.24, 0 g = 0.51 ± 0.35). The α-linolenic fatty acid decrease for the 0 g period was different than the 13 g (P = .024) and 26 g (P = .000) periods (13 g = 0.20 ± 0.04, 26 g = 0.35 ± 0.07, 0 g = -0.01 ± 0.07). Fructosamine, high sensitivity C-reactive protein, adiponectin, and high-sensitivity interleukin-6 had no significant differences. Flaxseed intake decreased glucose and insulin and improved insulin sensitivity as part of a habitual diet in overweight or obese individuals with pre-diabetes.

Adipokines and metabolic syndrome risk factors in women with previous gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) has been recognized as a significant risk factor for metabolic syndrome and CVD. The aim of the study was to evaluate the relationships between levels of cytokines, components of metabolic syndrome and cardiovascular risk markers in women with previous gestational diabetes.

METHODS

Women (n = 41) with gestational diabetes background (cases) and 21 healthy women (controls) in the postpartum period were enrolled. Demographic and clinical data, lipid and carbohydrate metabolism and uric acid and adipokine levels (TNF-α, IL-6, leptin and adiponectin) were compared and their relationships analysed. Metabolic syndrome prevalence was calculated by WHO and NCEP-ATPIII definitions.

RESULTS

There were significant differences between cases and controls: body mass index (kg/m(2) ) 27.4 ± 5.6 vs 23.9 ± 3.6 (p = 0.013), waist circumference (cm) 85.2 ± 12.9 vs 77.5 ± 9.0 (p = 0.017), metabolic syndrome (WHO definition) 14.6% vs 0% (p = 0.012), metabolic syndrome (NCEP-ATPIII definition) 22% vs 0% (p = 0.002), low HDL 36.6% vs 9.5% (p = 0.024), fasting glucose (mmol/L) 5.4 ± 0.6 vs 4.9 ± 0.2 (p < 0.001), glucose 120' oral glucose tolerance test (mmol/L) 5.8 ± 1.7vs 4.7 ± 0.8 (p = 0.007), fasting insulin (μU/mL) 13.4 ± 8.1 vs 8.4 ± 4.3 (p = 0.004), HOMA index 3.3 ± 2.3 vs 1.8 ± 1.0 (p = 0.002), HbA(1c) (%) 5.4 ± 0.2 vs 5.2 ± 0.2 (p = 0.021), uric acid (mg/dL) 4.1 ± 1 vs 3.5 ± 0.6 (p = 0.009), leptin (ng/mL) 32 025.5 ± 19 917.3 vs 20 258.9 ± 16 359.9 (p = 0.023), respectively.

CONCLUSIONS

Women with previous gestational diabetes have central adiposity, atherogenic lipid profile, carbohydrate intolerance and adverse adipokine profile, all of which are risk factors for the future development of metabolic disease and CVD.

Macronutrient composition and increased physical activity modulate plasma adipokines and appetite hormones during a weight loss intervention

BACKGROUND

We have shown previously that in overweight premenopausal women, changes in macronutrient composition and increasing the number of steps walked per day favorably affect body composition and plasma lipid profiles. As a follow-up, we evaluated the effect of moderate carbohydrate intake and increased physical activity on inflammation and regulation of appetite.

METHODS

Seventy premenopausal women with a body mass index (BMI) between 25 and 37 kg/m(2) participated in a 10-week weight loss intervention program consisting of the following macronutrient energy distribution: 40% carbohydrate, 30% fat, and 30% protein, in addition to a progressive increase in the number of steps taken per day. Plasma adiponectin, intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), leptin, and ghrelin levels were assessed at baseline and after 10 weeks.

RESULTS

Subjects reduced body weight by 4.5%, waist circumference (WC) by 6.4%, and trunk fat by 4.6%. Plasma insulin and insulin resistance assessed by homeostasis model assessment (HOMA) were reduced after 10 weeks (p < 0.01). Plasma adiponectin was increased by 11% (p < 0.05), and ICAM-1 levels were decreased (p < 0.05) after 10 weeks. A negative correlation was found between changes in insulin and changes in adiponectin between baseline and 10 weeks (r = -0.397, p < 0.01), indicating a role of adiponectin in increasing insulin sensitivity. In addition, plasma ghrelin levels were increased by 17% (p < 0.001), indicating a signal for increased appetite associated with weight loss.

CONCLUSIONS

These studies indicate that weight loss interventions involving moderate changes in dietary carbohydrate and increases in physical activity favorably affect insulin sensitivity and decrease inflammation.

The normoglycemic first-degree relatives of patients with type 2 diabetes mellitus have low circulating omentin-1 and adiponectin levels

OBJECTIVE

It has been suggested that adipose-derived cytokines act as insulin sensitizers/insulin-mimetics and some others may induce insulin resistance. In order to elucidate the potential role of novel adipocytokines in the pre-diabetes states, circulating levels of novel adipocytokines were evaluated in first-degree relatives of subjects with type 2 diabetes mellitus (FDRs).

METHOD

Serum omentin-1, adiponectin and retinol-binding protein 4 (RBP4) levels were measured in 179 subjects (90 glucose tolerant FDRs and 89 age- and sex-matched healthy controls) using enzyme-linked immunosorbent assay (ELISA) methods.

RESULTS

There was no significant difference between the two groups regarding serum RBP4 concentrations. However, serum omentin-1 (median [interquartile range], 6.18 [4.06-11.52]ng/ml versus 10.50 [4.30-20.60]ng/ml, p=0.004) and adiponectin (mean±SD, 10.07±4.0 μg/ml versus 20.66±8.12 μg/ml, p<0.0001) levels were significantly lower in FDRs when compared with the controls. In multiple logistic regression analysis, FDRs showed a significant association with lower circulating omentin-1 and adiponectin levels, even after adjustments were made for age, sex, body mass index, blood pressure measures, and biochemical parameters including glucose status, lipid profile, insulin levels and HOMA-IR (OR=0.49, CI [0.30-0.79]; p=0.004 and OR=0.74, CI [0.67-0.82]; p<0.0001, respectively). However, FDRs did not show a significant association with serum RBP4 levels in different models of regression analyses.

CONCLUSIONS

The FDRs showed significant associations with lower omentin-1 and adiponectin levels. A potential role for these adipokines in the FDRs' increased risk of diabetes needs to be further elucidated.

Plasma adiponectin concentration and its association with metabolic syndrome in patients with heart failure

PURPOSE

Plasma adiponectin concentrations are inversely related with metabolic syndrome (MetS), and MetS is associated with increased risk for heart failure (HF). However, the relationship between adiponectin and MetS in HF remains undetermined. Therefore, we tested whether MetS was associated with the degree of plasma adiponectin concentrations in HF patients.

MATERIALS AND METHODS

One hundred twenty eight ambulatory HF patients with left ventricular ejection fraction of <50% (80 males, 61.8 ± 11.9 years old) were enrolled for this cross-sectional study. Echocardiographic measurements were performed, and plasma concentrations of adiponectin, lipoproteins, apolipoproteins (apoB, apoA1) and high sensitive C-reactive protein (hsCRP) were measured.

RESULTS

Adiponectin concentrations in HF patients with MetS (n=43) were significantly lower than those without MetS (n=85) (9.7 ± 7.0 vs. 15.8 ± 10.9 μg/mL, p=0.001). Higher concentrations of apoB (p=0.017), apoB/A1 ratio (p<0.001), blood urea nitrogen (p=0.034), creatinine (p=0.003), and fasting insulin (p=0.004) were observed in HF patients with MetS compared with those without MetS. In HF patients with MetS, adiponectin concentrations were negatively correlated with hsCRP (r=-0.388, p=0.015) and positively correlated with the ratio of early mitral inflow velocity to early diastolic mitral annular velocity, E/E' (r=0.399, p=0.015). There was a significant trend towards decreased adiponectin concentrations with an increasing number of components of MetS (p for trend=0.012).

CONCLUSION

Our study demonstrated that adiponectin concentrations decreased in HF patients with MetS, and that relationship between adiponectin, inflammation and abnormal diastolic function, possibly leading to the progression of HF.

Low circulating adiponectin levels are associated with insulin resistance in non-obese peritoneal dialysis patients

In patients with end-stage renal disease (ESRD), circulating adipokine levels are increased due to decreased renal clearance, irrespective of obesity. However, whether adipokines play a role in the development of insulin resistance (IR) in non-obese ESRD patients is unknown. We conducted a cross-sectional study to identify factors associated with IR in 62 non-obese patients on peritoneal dialysis (PD). Non-obesity was defined as body mass index (BMI) <25 kg/m(2). IR was determined using homeostatic model assessment-IR (HOMA-IR). We also measured serum concentrations of adiponectin, leptin, resistin, high-sensitivity C-reactive protein (hsCRP), and IL-6. The average BMI of the study patients was 21.6 kg/m(2). When patients were divided into two groups according to the median value of HOMA-IR, serum adiponectin levels were significantly lower in patients with HOMA-IR > 1.85 than in those with HOMA-IR ≤1.85, whereas serum concentrations of leptin and resistin did not differ between the two groups. In addition, log-transformed HOMA-IR was negatively correlated with adiponectin (γ = -0.464, P < 0.001) and log-transformed high-density lipoprotein cholesterol (γ = -0.250, P = 0.050) and positively correlated with age (γ = 0.334, P = 0.008) and triglyceride (γ = 0.392, P = 0.002). However, resistin, log-transformed leptin and log-transformed hsCRP were not associated with HOMA-IR. In a multiple linear regression model, adiponectin was independently associated with HOMA-IR (β = -0.023, P = 0.015). In conclusion, this study suggests that low circulating adiponectin levels might be involved in IR even in non-obese patients undergoing PD.

Relation of adiponectin to glucose tolerance status, adiposity, and cardiovascular risk factor load

Objective. Adiponectin has anti-atherogenic and anti-inflammatory properties. We investigated the influence of adiponectin on glucose tolerance status, adiposity and cardiovascular risk factors (CVRFs). Design and Patients. Study consisted of 107 subjects: 55 with normal glucose tolerance (NGT) and 52 with impaired glucose regulation (IGR) who were divided into two groups: 24 subjects with impaired fasting glucose (IFG Group) and 28 patients with type 2 diabetes mellitus (DM Group). In additional analysis, study participants were divided into two groups, according to CVRFs: low and high risk. Measurements: Patients were evaluated for glucose, HbA1C, insulin, lipids, CRP, HOMA-IR and adiponectin. Measurements. Patients were evaluated for glucose, HbA1C, insulin, lipids, CRP, HOMA-IR and adiponectin. Results. Adiponectin was significantly higher in NGT group than in IFG (P = 0.003) and DM (P = 0.01) groups. Adiponectin was significantly, positively associated with HDL and inversely associated with glucose, HbA1c, ALT, AST, TG, HOMA-IR. Patients with higher CVRFs load have lesser adiponectin compared to patients with low cardiovascular risk P < 0.0001). Adiponectin was inversely associated with the number of risk factors (r = −0.430, P = 0.0001). Conclusions. Circulating adiponectin was significantly lower in subjects with different degree of IGR compared to subjects with normal glucose homeostasis. Adiponectin was significantly lower in high risk group than low risk group and decreased concurrently with increased number of CVRFs.

Energy intake and adiponectin gene expression

Hypoadiponectinemia and decreased adiponectin gene expression in white adipose tissue (WAT) have been well observed in obese subjects and animal models. However, the mechanism for obesity-associated hypoadiponectinemia is still largely unknown. To investigate the regulatory role of energy intake, dietary fat, and adiposity in adiponectin gene expression and blood adiponectin level, a series of feeding regimens was employed to manipulate energy intake and dietary fat in obese-prone C57BL/6, genetically obese ob/ob, obese-resistant A/J and peroxisome proliferator-activated receptor-α gene knockout (PPARα KO) mice. Adiponectin gene expression in WAT and circulating adiponectin levels were studied in these dietary intervention-treated mice. Our study showed that calorie restriction (CR) robustly increased adiponectin gene expression in epididymal fat and blood adiponectin levels in both low-fat (LF) and high-fat (HF) diet-fed C57BL/6 mice. Although HF pair-fed C57BL/6 mice received the same amount of calories as LF ad libitum-fed mice, HF diet clearly increased adiposity but showed no significant effects on adiponectin gene expression and blood adiponectin level. CR also significantly increased blood adiponectin levels in ob/ob and A/J mice. Neither CR nor HF feeding displayed any significant effect on blood adiponectin half-life in C57BL/6 mice. Interestingly, CR increased PPARα expression in epididymal fat of C57BL/6 mice. Low levels of blood adiponectin and adiponectin gene expression in WAT were observed in PPARα KO mice. PPARα agonist treatment increased adiponectin mRNA levels in 3T3-L1 adipocytes. Furthermore, CR failed to increase adiponectin gene expression and blood adiponectin levels in PPARα KO mice. Therefore, our study demonstrated that energy intake, not dietary fat, plays an important role in regulating adiponectin gene expression and blood adiponectin level. PPARα mediates CR-enhanced adiponectin gene expression in WAT.

Plasminogen activator inhibitor-1 (PAI-1): a key factor linking fibrinolysis and age-related subclinical and clinical conditions

INTRODUCTION

The close relationship existing between aging and thrombosis has growingly been studied in this last decade. The age-related development of a prothrombotic imbalance in the fibrinolysis homeostasis has been hypothesized as the basis of this increased cardiovascular and cerebrovascular risk. Fibrinolysis is the result of the interactions among multiple plasminogen activators and inhibitors constituting the enzymatic cascade, and ultimately leading to the degradation of fibrin. The plasminogen activator system plays a key role in a wide range of physiological and pathological processes.

METHODS

Narrative review.

RESULTS

Plasminogen activator inhibitor-1 (PAI-1) is a member of the superfamily of serine-protease inhibitors (or serpins), and the principal inhibitor of both the tissue-type and the urokinase-type plasminogen activator, the two plasminogen activators able to activate plasminogen. Current evidence describing the central role played by PAI-1 in a number of age-related subclinical (i.e., inflammation, atherosclerosis, insulin resistance) and clinical (i.e., obesity, comorbidities, Werner syndrome) conditions is presented.

CONCLUSIONS

Despite some controversial and unclear issues, PAI-1 represents an extremely promising marker that may become a biological parameter to be progressively considered in the prognostic evaluation, in the disease monitoring, and as treatment target of age-related conditions in the future.

Adiponectin Levels in Non-obese First-degree Relatives of Type 2 Diabetes Patients and Non-diabetic Subjects: A 5-Year Follow-up Study

This study was designed to investigate adiponectin levels and their relationship to various parameters at baseline and after 5 years in non-obese first-degree relatives of type 2 diabetes patients (FDR group) versus subjects without a family history of diabetes (normal group). Adiponectin levels at baseline were lower in the FDR group versus the normal group. After 5 years, adiponectin levels had fallen significantly in both the FDR (24.3% reduction) and the normal (35.7% reduction) groups. Adiponectin levels were negatively correlated with waist/hip ratio, fasting plasma glucose, carotid intima-media thickness (IMT) and insulin resistance in the FDR group. When adjusted for relevant risk factors, adiponectin was associated with age, high-density lipoprotein-cholesterol and IMT; these factors explained 45% of the variation in adiponectin in the FDR group. In the normal group, multiple regression analyses revealed that low-density lipoprotein-cholesterol and IMT explained 25% of the variability in the adiponectin concentration. In both groups, however, the correlation between adiponectin and IMT just failed to reach statistical significance in this population group. We conclude that adiponectin levels were reduced in non-obese first-degree relatives of patients with type 2 diabetes and normal individuals over a 5-year period. This study supports previous findings that hypoadiponectinaemia is a risk factor for atherosclerosis.

High-molecular-weight adiponectin and incident ischemic stroke in postmenopausal women: a Women's Health Initiative Study

BACKGROUND AND PURPOSE

Although low levels of adiponectin are associated with coronary heart disease and cardiovascular disease risk factors, it is unclear whether adiponectin levels are related to the risk of developing ischemic stroke.

METHODS

We examined the relationship between baseline high-molecular-weight (HMW) adiponectin levels and incident ischemic stroke in postmenopausal women using data and specimens from the Hormones and Biomarkers Predicting Stroke Study, a case-control study nested within the Women's Health Initiative Observational Study. Included were 855 incident ischemic stroke cases and 855 control subjects matched for age, race-ethnicity, date of entry into the cohort, and follow-up time. ORs of incident ischemic stroke associated with baseline HMW adiponectin levels were calculated using conditional logistic regression modeling adjusting for body mass index, type 2 diabetes, hypertension, smoking, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, physical activity, C-reactive protein, and aspirin use.

RESULTS

Lower levels of HMW adiponectin were significantly associated with type 2 diabetes, hypertension, higher body mass index, waist circumference, glucose, and insulin levels and lower high-density lipoprotein cholesterol levels. The distribution of incident stroke cases by HMW adiponectin quartiles was 49.9%, 50.5%, 50.7%, and 48.9%, respectively (P=0.96). Multivariable-adjusted ORs of stroke associated with the top 3 quartiles of HMW adiponectin versus the first quartile were 0.99 (95% CI, 0.71 to 1.37), 1.37 (0.99 to 1.91), and 1.25 (0.88 to 1.79), respectively (P trend=0.14).

CONCLUSIONS

Despite moderate associations between HMW adiponectin and cardiovascular disease risk factors, we found no evidence of an association between HMW adiponectin levels and incident ischemic stroke in these postmenopausal women.

Overcoming metabolic syndrome in severe obesity: adiponectin as a marker of insulin sensitivity and HDL-cholesterol improvements after gastric bypass

OBJECTIVE

To assess the relationship between adiponectin and metabolic parameters in severely obese women during surgical-induced weight loss.

METHODS

Nineteen lean (CT - BMI:21.2 +/- 0.3 kg.m(2)), 14 overweight/class II obese (OB/OW - BMI: 29.7 +/- 0.7 kg/m(2)) and 8 morbidly obese (OBIII - BMI: 56.4 +/- 3.6 kg/m(2)) were evaluated by hyperinsulinemic-euglycemic clamp, adiponectin, and lipids. OBIII were evaluated at 5th and 16th month post-operatively.

RESULTS

Compared to lean, obese groups had lower adiponectin (OB/OW: 9.4 +/- 0.9, OBIII: 7.1 +/- 1.3 versus 12.2 +/- 0.9 ng/dL; p < 0.01), lower HDL-cholesterol (OB/OW:1.05 +/- 0.05, OBIII: 0.88 +/- 0.04 versus 1.22 +/- 0.07 mmol/L; p < 0.01) and insulin resistance-IR (glucose uptake, M-value - OB/OW: 43.6 +/- 2.7, OBIII: 32.4 +/- 3.2 versus 20.0 +/- 1.8 umol/kgFFM.min; p < 0.001). Considering all subjects, adiponectin levels were inversely correlated to BMI and waist circumference, and directly to M-value and HDL-cholesterol (p < 0.01). During weight loss, improvements in IR (Study III: 36.1 +/- 3.9 umol/kg/FFM.min, p < 0.0001), adiponectin (11.8 +/- 1.4 ng/dL, p = 0.006) and HDL-cholesterol were observed (1.10 +/- 0.04 mmol/L, p = 0.007). Moreover, HDL-cholesterol improvement was significantly and independently related to variations of adiponectin and BMI (r(2) = 0.86; p < 0.0002).

CONCLUSIONS

The improvements of IR and adiponectin were related to surgical-induced weight loss, suggesting an important role of adiponectin in HDL-cholesterol regulation.

Fat tissue and adiponectin: new players in critical care?

Historically, adipose tissue was thought to be a passive tissue that stores energy and protects the body from temperature and injury. In contrast to this concept, it is now evident that adipose tissue is an active endocrine organ secreting many kinds of adipocytokines, including adiponectin. Presumably, adipose tissue and its products may have some impact on numerous pathways of response to trauma, sepsis and stress. The discussion on a plausible role of adiponectin in critical illness has been raised by the fact of finding hypoadiponectinemia in critically ill patients. The nature of this phenomenon, however, remains to be elucidated, and noteworthy clinical studies should prompt further efforts in basic research to explain the mechanisms beyond the clinical observation of low adiponectin levels in humans with severe illness.

Children with type 2 diabetes mellitus are at greater risk of macrovascular complications

BACKGROUND

Type 2 diabetes mellitus (DM) is a risk factor for macrovascular complications in adults. Recently young-onset type 2 DM has increased worldwide and the increase of macrovascular complications in the young is worrisome.

METHODS

Plasma values for plasminogen activator inhibitor-1 (PAI-1) as a marker for promotion, and adiponectin as a marker for inhibition of atherosclerosis, were compared in 33 patients with type 1 DM (16 boys, 17 girls; age 14.9 +/- 3.7 years, mean +/- standard deviation) with those of 43 patients with type 2 DM (15 boys, 28 girls; age 16.5 +/- 3.5 years).

RESULTS

The PAI-1 level was significantly higher (19.3 +/- 8.1 vs 32.9 +/- 17.2 ng/ml; P < 0.001) and the adiponectin level was significantly lower (10.1 +/- 3.8 vs 7.4 +/- 3.7 microg/ml; P < 0.005) in the type 2 DM group. In obese patients, the PAI-1 level was significantly higher (P < 0.005) and the adiponectin level was lower (P= 0.15) in the type 2 DM group. Also, in the non-obese subjects, the PAI-1 level was significantly higher (P < 0.05) and the adiponectin level was lower (P= 0.11) in the type 2 DM group.

CONCLUSIONS

Even in young patients, type 2 DM is a risk factor for macrovascular complications compared with type 1 DM.

Serum adiponectin is associated with family history of diabetes independently of obesity and insulin resistance in healthy Korean men and women

BACKGROUND

Adiponectin has been reported as a new risk factor for the development of diabetes. However, it is not clear whether adiponectin levels are associated with family history of diabetes (FHD).

OBJECTIVE

The objective of this study was to measure the independent association of serum adiponectin with FHD in relation to insulin resistance and obesity.

METHODS

In 2006, a cross-sectional study was conducted in which waist circumference (WC), body mass index (BMI), and serum adiponectin were measured in 5919 healthy Korean men and women. Multiple linear regression models were used to assess the association of serum adiponectin levels with FHD. The population was classified into two groups according to median values for each of the following variables: WC, BMI, and homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

The positive FHD group had higher HOMA-IR and lower adiponectin levels in both men and women than those without FHD. Adiponectin levels were significantly associated with FHD in men and women respectively, after adjusting for age, BMI, and alcohol consumption (P=0.0123 and 0.0004). The relationship between adiponectin and FHD was similar between the high and low insulin resistance, BMI, and WC groups in male non-smokers and in all Korean women.

CONCLUSION

These results confirm that adiponectin levels are associated with FHD. These data also suggest that the association of serum adiponectin with FHD may be independent of obesity and insulin resistance.

Adiponectin and its response to thiazolidinediones are associated with insulin-mediated glucose metabolism in type 2 diabetic patients and their first-degree relatives

Patients with type 2 diabetes (T2D) and their first-degree relatives (FDRs) are characterized by hypoadiponectinaema and insulin resistance. In T2D patients, plasma adiponectin and insulin sensitivity (SI) increase in response to thiazolidinediones (TZDs). These findings suggest a role for adiponectin in the regulation of SI. We studied the relationship between plasma adiponectin and glucose and lipid metabolism and the effect of troglitazone (200 mg/day) for 12 weeks in 19 normoglycaemic, obese FDR and 20 obese T2D patients, using euglycaemic-hyperinsulinaemic clamps, glycolytic flux calculations and indirect calorimetry. Plasma adiponectin was similar in both groups, despite higher glucose disposal (Rd), glucose oxidation and glycolytic flux and lower lipid oxidation during insulin stimulation in FDR compared with T2D patients. Plasma adiponectin correlated with insulin-stimulated Rd, non-oxidative glucose disposal (NOGD), glucose storage and SI in both groups after adjustment for sex and body fat. The troglitazone-mediated upregulation of plasma adiponectin was associated with increased insulin-stimulated Rd, NOGD and glucose storage in both groups. No effect on endogenous glucose production was observed. In FDR, plasma adiponectin correlated with insulin-stimulated glycogen synthase activity and the troglitazone-induced increase in plasma adiponectin correlated with the improvement in insulin-stimulated Rd and SI after adjustment for sex and body fat. In conclusion, plasma adiponectin in weight-matched FDR and T2D patients is comparably low and correlates with insulin-mediated glucose uptake and storage. Moreover, these data provide evidence for an adiponectin-dependent insulin-sensitizing effect of TZDs at an early stage before development of T2D and that this effect is exerted mainly on insulin-mediated glucose metabolism.

Adipokines and insulin resistance

Obesity is associated with an array of health problems in adult and pediatric populations. Understanding the pathogenesis of obesity and its metabolic sequelae has advanced rapidly over the past decades. Adipose tissue represents an active endocrine organ that, in addition to regulating fat mass and nutrient homeostasis, releases a large number of bioactive mediators (adipokines) that signal to organs of metabolic importance including brain, liver, skeletal muscle, and the immune system--thereby modulating hemostasis, blood pressure, lipid and glucose metabolism, inflammation, and atherosclerosis. In the present review, we summarize current data on the effect of the adipose tissue-derived hormones adiponectin, chemerin, leptin, omentin, resistin, retinol binding protein 4, tumor necrosis factor-alpha and interleukin-6, vaspin, and visfatin on insulin resistance.

Combined association of maternal and paternal family history of diabetes with plasma leptin and adiponectin in overweight Hispanic children

AIMS

To investigate the importance of a maternal and paternal family history of Type 2 diabetes and their combined association with plasma leptin and adiponectin levels in overweight Latino children with a family history of Type 2 diabetes (T2DM).

METHODS

This cross-sectional study investigated the combined association of a maternal and paternal family history of T2DM with leptin and adiponectin in 175 overweight Latino children (age 11.1 +/- 1.7 years). All subjects had a family history of T2DM. Plasma adiponectin and leptin levels, body fat measured by dual-energy X-ray absorptiometry, Tanner stage, age and insulin sensitivity were assessed.

RESULTS

After adjustment for age, gestational diabetes, insulin sensitivity and body fat, a combined maternal and paternal family history of T2DM was associated with higher leptin concentrations (P = 0.004) compared with a maternal or paternal family history alone. This association was most pronounced at Tanner stage 1 (P for interaction family history x tanner stage = 0.022). The presence of a combined maternal and paternal family history of T2DM accounted for 4% (P = 0.003) of the variation in leptin concentrations. No such combined association was observed for adiponectin levels.

CONCLUSIONS

Maternal and paternal family history of T2DM may have an additive impact on leptin, but not on adiponectin levels independent of adiposity and insulin sensitivity in overweight Latino children. This may contribute to a further clinically relevant deterioration of metabolic health in this population.

High plasma retinol binding protein-4 and low plasma adiponectin concentrations are associated with severity of glucose intolerance in women with previous gestational diabetes mellitus

CONTEXT

Women with previous gestational diabetes mellitus (pGDM) are at high risk of developing type 2 diabetes mellitus in the future. The role of adipokines in women with pGDM has not been established.

OBJECTIVE

We investigated whether circulating adipokine concentration is associated with abnormal glucose homeostasis in women with pGDM. DESIGN, SETTING, PATIENTS, AND MAIN OUTCOME MEASURES: We measured the plasma concentrations of retinol-binding protein-4 (RBP4), transthyretin (TTR), and adiponectin and metabolic parameters in four groups of women who exhibited normal glucose tolerance (NGT) during a previous pregnancy (NP, n = 17), NGT after GDM (GDM-NGT, n = 72), impaired glucose tolerance after GDM (GDM-IGT, n = 60), and type 2 diabetes after GDM (GDM-DM, n = 8).

RESULTS

Plasma RBP4 concentration was significantly higher in women with GDM-DM, GDM-IGT, and GDM-NGT than in those with NP. RBP4 concentration correlated positively with TTR concentration; fasting plasma glucose, insulin, and triglyceride concentrations; blood pressure; abdominal fat area; and homeostasis model assessment of insulin resistance. Plasma TTR concentration was elevated in women with GDM-DM compared with other groups. In contrast, adiponectin concentration was lowest in the GDM-DM group and correlated inversely with parameters of insulin resistance. Resistin concentration was higher only in the GDM-NGT and GDM-IGT groups, whereas leptin did not differ between groups. Plasma RBP4 and adiponectin concentrations were inversely correlated.

CONCLUSIONS

The severity of glucose intolerance in women with pGDM is associated with high RBP4 and low adiponectin concentrations.

Role of resistin in cardiac contractility and hypertrophy

Cardiovascular sequelae including diabetic cardiomyopathy constitute the major cause of death in diabetic patients. Although several factors may contribute to the development of this cardiomyopathy, the underlying molecular/cellular mechanisms leading to cardiac dysfunction are still partially understood. Recently, a novel paradigm for the role of the adipocytokine resistin in diabetes has emerged. Resistin has been proposed to be a link between obesity, insulin resistance and diabetes. Using microarray analysis, we have recently found that cardiomyocytes isolated from type 2 diabetic hearts express high levels of resistin. However, the function of resistin with respect to cardiac function is unknown. In this study we show that resistin is not only expressed in the heart, but also promotes cardiac hypertrophy. Adenovirus-mediated overexpression of resistin in cultured neonatal rat ventricular myocytes (NRVM) significantly increased sarcomere organization and cell size, increased protein synthesis and increased the expression of atrial natriuretic factor and beta-myosin heavy chain. Overexpression of resistin in NRVM was also associated with activation of the mitogen-activated protein (MAP) kinases, ERK1/2 and p38, as well as increased Ser-636 phosphorylation of insulin receptor substrate-1 (IRS-1), indicating that IRS-1/MAPK pathway may be involved in the observed hypertrophic response. Overexpression of resistin in adult cultured cardiomyocytes significantly altered myocyte mechanics by depressing cell contractility as well as contraction and relaxation velocities. Intracellular Ca(2+) measurements showed slower Ca(2+) transients decay in resistin-transduced myocytes compared to controls, suggesting impaired cytoplasmic Ca(2+) clearing or alterations in myofilament activation. We conclude that resistin overexpression alters cardiac contractility, confers to primary cardiomyocytes all the features of the hypertrophic phenotype and promotes cardiac hypertrophy possibly via the IRS-1/MAPK pathway.

Serum adiponectin and leptin concentrations in patients with chronic pancreatitis of alcoholic and nonalcoholic origin

OBJECTIVE

The aim of this study was to assess serum adiponectin and leptin concentrations in patients with chronic pancreatitis of alcoholic and nonalcoholic origin.

METHODS

Forty-four male patients with chronic pancreatitis of alcoholic origin and 10 patients of nonalcoholic origin as well 16 healthy subjects were examined. Fasting blood samples were collected. Serum adiponectin, leptin, and insulin concentrations were determined by radioimmunoassay methods.

RESULTS

Patients with chronic pancreatitis had lower body mass index values compared with those of control. Nonetheless, there were no differences in serum adiponectin concentration between pancreatitis patients and healthy controls. Pancreatitis patients had lower serum leptin and insulin concentrations than healthy subjects. No difference in serum leptin and insulin concentrations between patients with chronic pancreatitis of alcoholic and nonalcoholic origin was observed. The serum adiponectin/leptin concentration ratio was higher in chronic pancreatitis patients than in control subjects.

CONCLUSIONS

Chronic pancreatitis in humans (a) is associated with the decrease in serum leptin and insulin concentrations, (b) does not affect serum adiponectin concentration but increases serum adiponectin/leptin concentration ratio, and (c) alters the interrelationship between serum adiponectin and insulin concentrations. Moreover, these results suggest that changes in serum leptin and insulin concentrations are independent on the etiology of chronic pancreatitis.

No evidence of an effect of alterations in dietary fatty acids on fasting adiponectin over 3 weeks

OBJECTIVE

Little is known about the effects of alterations in fatty acid classes on adiponectin, a hormone secreted by the adipocyte known to be important in the development of diabetes and cardiovascular disease (CVD). Any factor, including diet, that may positively influence adiponectin gene expression or increase circulating levels might be useful for improving such metabolic abnormalities. We investigated the effects of alterations in dietary fatty acid saturation on fasting serum adiponectin and associated peptides.

METHODS AND PROCEDURES

Double-blind, randomized, crossover, 2 x 3-week residential intervention trial where 18 mildly hyperlipidemic adult men were provided with a high saturated:unsaturated fat (SFA:USFA) and lower SFA:USFA treatment separated by an uncontrolled 4-week washout. Only fatty acid profile was altered between treatments. Fasting blood samples were collected on days 0, 1, 7, 14, 21, 22 of each intervention period for the measurement of adiponectin, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsC-RP), leptin, and ghrelin.

RESULTS

Body weight was kept constant (+/-1 kg) throughout each treatment. There was no detectable difference in fasting adiponectin at baseline (mean day 0 + day 1) between the treatment groups (mean +/- s.d.; high(SFA:USFA) = 7.0 +/- 1.7 vs. low(SFA:USFA) = 6.7 +/- 1.4 microg/ml, P > 0.05). There were neither significant between-treatment effects of fatty acid saturation (diet x time, P > 0.05) on serum adiponectin nor any significant between-treatment effects on serum TNF-alpha, IL-6, hsC-RP, leptin, or ghrelin (P > 0.05).

DISCUSSION

Fasting serum adiponectin was not detectably affected by alterations in dietary fatty acid profile in mildly hyperlipidemic men. There was no evidence that an increase in SFA content of the diet significantly worsened fasting serum adiponectin over a 3-week intervention period.

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.

Low physical activity and obesity: causes of chronic disease or simply predictors?

BACKGROUND AND PURPOSE

Many studies have shown associations between risk of morbidity and mortality with both obesity and low physical activity (PA), but association does not imply causality. Moreover, there is an inverse relationship between PA and obesity; therefore, controlling for one of these factors when investigating the risk associated with the other is essential. The purpose of this review is to determine whether low PA and obesity actually cause metabolic dysfunction and chronic disease, especially type 2 diabetes (T2D), rather than simply operating as predictors or markers.

METHODS

The case for causality is strengthened if the following two conditions are satisfied: first, that significant associations between obesity or low PA and risk persist after controlling appropriately; and second, that the physiological mechanisms by which obesity or low PA may exert a causal effect are clearly established. The studies examined include those that have used cardiorespiratory (CR) fitness as a surrogate measure for PA, thus also providing evidence for low CR fitness as an independent risk factor in its own right.

RESULTS AND CONCLUSIONS

Low PA and poor CR fitness are independent predictors of mortality related to type 2 diabetes and chronic disease in general. Together with well-demonstrated mechanisms, there is strong evidence that low PA and low CR fitness are direct, independent causes of metabolic dysfunction and type 2 diabetes. Despite some reports to the contrary, there is evidence that both general and visceral obesity are predictors of mortality and morbidity after controlling for PA. However, in the absence of established mechanisms, evidence is insufficient to conclude that either general or visceral obesity is a direct, independent cause of metabolic dysfunction or type 2 diabetes.