Antiatherosclerotic and anti-insulin resistance effects of adiponectin: basic and clinical studies

AKT Mediates Adiponectin-Dependent Regulation of VSMC Phenotype

Adiponectin (adipoq), the most abundant hormone in circulation, has many beneficial effects on the cardiovascular system, in part by preserving the contractile phenotype of vascular smooth muscle cells (VSMCs). However, the lack of adiponectin or its receptor and treatment with recombinant adiponectin have shown contradictory effects on plaque in mice. RNA sequence of Adipoq+/+ and adipoq-/- VSMCs from male aortas identified a critical role for adiponectin in AKT signaling, the extracellular matrix (ECM), and TGF-β signaling. Upregulation of AKT activity mediated proliferation and migration of adipoq-/- cells. Activation of AMPK with metformin or AdipoRon reduced AKT-dependent proliferation and migration of adipoq-/- cells but did not improve the expression of contractile genes. Adiponectin deficiency impaired oxidative phosphorylation (OXPHOS), increased expression of glycolytic enzymes, and elevated mitochondrial reactive oxygen species (ROS) (superoxide, and hydrogen peroxide). Anti-atherogenic mechanisms targeted the ECM in adipoq-/- cells, downregulating MMP2 and 9 and upregulating decorin (DCN) and elastin (ELN). In vivo, the main sex differences in protein expression in aortas involved a more robust upregulation of MMP3 in females than males. Females also showed a reduction in DCN, which was not affected in males. Our study uncovered the AKT/MAPK/TGF-β network as a central regulator of VSMC phenotype.

The Different Pathways of Epicardial Adipose Tissue across the Heart Failure Phenotypes: From Pathophysiology to Therapeutic Target

Epicardial adipose tissue (EAT) is an endocrine and paracrine organ constituted by a layer of adipose tissue directly located between the myocardium and visceral pericardium. Under physiological conditions, EAT exerts protective effects of brown-like fat characteristics, metabolizing excess fatty acids, and secreting anti-inflammatory and anti-fibrotic cytokines. In certain pathological conditions, EAT acquires a proatherogenic transcriptional profile resulting in increased synthesis of biologically active adipocytokines with proinflammatory properties, promoting oxidative stress, and finally causing endothelial damage. The role of EAT in heart failure (HF) has been mainly limited to HF with preserved ejection fraction (HFpEF) and related to the HFpEF obese phenotype. In HFpEF, EAT seems to acquire a proinflammatory profile and higher EAT values have been related to worse outcomes. Less data are available about the role of EAT in HF with reduced ejection fraction (HFrEF). Conversely, in HFrEF, EAT seems to play a nutritive role and lower values may correspond to the expression of a catabolic, adverse phenotype. As of now, there is evidence that the beneficial systemic cardiovascular effects of sodium-glucose cotransporter-2 receptors-inhibitors (SGLT2-i) might be partially mediated by inducing favorable modifications on EAT. As such, EAT may represent a promising target organ for the development of new drugs to improve cardiovascular prognosis. Thus, an approach based on detailed phenotyping of cardiac structural alterations and distinctive biomolecular pathways may change the current scenario, leading towards a precision medicine model with specific therapeutic targets considering different individual profiles. The aim of this review is to summarize the current knowledge about the biomolecular pathway of EAT in HF across the whole spectrum of ejection fraction, and to describe the potential of EAT as a therapeutic target in HF.

Serum Adiponectin and Nitric Oxide Levels in Type II Diabetes and Its Correlation With Lipid Profile

Introduction

Various markers for diabetes have been identified in this new era of medicine, the most recent being adiponectin, which is primarily secreted from adipose tissue and has anti-diabetic, anti-inflammatory, and anti-atherogenic properties. It is also known to increase insulin sensitivity. Adiponectin deficiency or decreased secretion causes a variety of complications, including insulin resistance and the onset of type 2 diabetes mellitus (T2DM). One such complication of T2DM is endothelial dysfunction, which leads to decreased synthesis of nitric oxide (NO), another potent marker that normally disrupts key events in the progression of atherosclerosis.

Aims and objectives

The aim of the study was to compare and correlate serum adiponectin and nitric oxide levels with glycemic status in patients with T2DM and healthy controls.

Materials and methods

This comparative cross-sectional study included known cases of type II diabetes under group I and healthy age-matched controls under group II. Serum levels of adiponectin and nitric oxide were assessed in both the groups along with glycemic status [fasting blood sugar (FBS) and glycated hemoglobin (HbA1c)] and these parameters were compared between both groups using a t-test. Adiponectin and NO levels were correlated using Pearson’s correlation with glycemic status in group I.

Results

The mean adiponectin levels in group I were 5.94 ± 1.490 μg/mL, which was significantly (p<0.00) less than in group II, 10.30 ±1.669 μg/mL. The mean NO levels in group I (42.98 ± 6.300 μmol/L) were also significantly (p<0.00) less than in group II (56.126 ± 7.579 μmol/L). FBS and HbA1C levels were significantly higher in group I than in group II.

Conclusion

Adiponectin and NO levels were significantly reduced in individuals with T2DM when compared to healthy controls. Therapeutic interventions that increase adiponectin and NO levels may be useful targets for improving diabetes control and reducing complications.

From Anti-SARS-CoV-2 Immune Response to the Cytokine Storm via Molecular Mimicry

The aim of this study was to investigate the role of molecular mimicry in the cytokine storms associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Human proteins endowed with anti-inflammatory activity were assembled and analyzed for peptide sharing with the SARS-CoV-2 spike glycoprotein (gp) using public databases. It was found that the SARS-CoV-2 spike gp shares numerous pentapeptides with anti-inflammatory proteins that, when altered, can lead to cytokine storms characterized by diverse disorders such as systemic multiorgan hyperinflammation, macrophage activation syndrome, ferritinemia, endothelial dysfunction, and acute respiratory syndrome. Immunologically, many shared peptides are part of experimentally validated epitopes and are also present in pathogens to which individuals may have been exposed following infections or vaccinal routes and of which the immune system has stored memory. Such an immunologic imprint might trigger powerful anamnestic secondary cross-reactive responses, thus explaining the raging of the cytokine storm that can occur following exposure to SARS-CoV-2. In conclusion, the results support molecular mimicry and the consequent cross-reactivity as a potential mechanism in SARS-CoV-2-induced cytokine storms, and highlight the role of immunological imprinting in determining high-affinity, high-avidity, autoimmune cross-reactions as a pathogenic sequela associated with anti-SARS-CoV-2 vaccines.

Adiponectin and cardiometabolic trait and mortality: where do we go?

Adiponectin is an adipocyte-derived cytokine known for its cardioprotective effects in preclinical studies. Early epidemiologic studies replicated these findings and drew great interest. Subsequent large-scale prospective cohorts, however, showed that adiponectin levels seemed not to relate to incident coronary artery disease (CAD). Even more surprisingly, a paradoxical increase of all-cause and cardiovascular (CV) mortality with increased adiponectin levels was reported. The adiponectin-mortality paradox has been explained by some groups asserting that adiponectin secretion is promoted by elevated natriuretic peptides (NP). Other groups have proposed that adiponectin is elevated due to adiponectin resistance in subjects with metabolic syndrome or heart failure (HF). However, there is no unifying theory that can clearly explain this paradox. In patients with HF with reduced ejection fraction (HFrEF), stretched cardiomyocytes secrete NPs, which further promote release of adiponectin from adipose tissue, leading to adiponectin resistance. On the other hand, adiponectin biology may differ in patients with heart failure with preserved ejection fraction (HFpEF), which constitutes 50% of all of HF. Most HFpEF patients are obese, which exerts inflammation and myocardial stiffness, that is likely to prevent myocardial stretch and subsequent NP release. This segment of the patient population may display a different adiponectin biology from its HFrEF counterpart. Dissecting the adiponectin-mortality relation in terms of different HF subtypes may help to comprehensively understand this paradox. Mendelian Randomization (MR) analyses claimed that adiponectin levels are not causally related to CAD or metabolic syndrome. Results from MR studies, however, should be interpreted with great caution because the underlying history of CAD or CHF were not taken into account in these analyses, an issue that may substantially confound the results. Here, we discuss many aspects of adiponectin; cardiometabolic traits, therapeutic interventions, and the ongoing debate about the adiponectin paradox, which were recently described in basic, epidemiologic, and clinical studies.

Increased epicardial adipose tissue thickness associated with increased metabolic risk and the presence of heart failure in patients with Chronic Chagas disease

BACKGROUND

It has been described that Trypanosoma cruzi is capable of promoting metabolic disturbances currently considered as cardiovascular risk factors. Moreover, it has been observed that the protozoa can remain in adipose tissue and alter its immune endocrine functions. The aim of this study was to characterize the thickness of epicardial adipose tissue (EAT) in patients with chronic Chagas disease (CCD) concerning their cardiovascular metabolic risk profile compared with those without CCD.

METHODS

A cross-sectional study was performed including T. cruzi seropositive individuals categorized according to a standard CCD classification and a matched seronegative control group. Complete clinical examination, metabolic laboratory tests and transthoracic echocardiography to assess cardiac function and to quantify EAT were performed.

RESULTS

Fifty-five individuals aged 46.7±11.9 y, 34 with CCD and 21 in the control group, were included. The CCD group presented higher EAT thickness in relation to controls (4.54±1.28 vs 3.22±0.99 mm; p=0.001), which was significantly associated with the presence of insulin resistance (OR=3, 95% CI 1.58 to 5.73; p<0.001). This group presented lower levels of plasmatic adiponectin than controls, especially in those patients with EAT ≥4.5 mm (p=0.005) who also presented with heart failure more frequently (p=0.01).

CONCLUSION

In patients with CCD, a higher EAT thickness is observed and is associated with an increased metabolic risk profile indicated mainly by insulin resistance.

Possible value of galectin-3 on follow-up of cardiac remodeling during glucocorticoid treatment

Glucocorticoids are among the most prescribed drugs globally due to their potent anti-inflammatory and immunosuppressive properties. Although they have positive effects on the treatment of various disease states; long-term administration is associated with high blood pressure, insulin resistance, and susceptibility to type 2 diabetes. The heart attempts to cope with increased blood pressure and a decrease in glucose utilization by developing pathological cardiac remodeling. However, in this process, cardiac fibrosis formation and deterioration in heart structure and functions occur. Galectin-3, a member of the β-galactoside binding lectins, is consistently associated with inflammation and fibrosis in the pathogenesis of various disease states including insulin resistance and heart failure. Galectin-3 expression is markedly increased in activated macrophages and a subset of activated fibroblasts and vascular cells. Also, failing and remodeling myocardium show increased Gal-3 expression and elevated Gal-3 levels are related to heart failure severity and prognosis. Furthermore, Gal-3-related pathways are recently suggested as therapeutic targets both pharmacologically and genetically to increase insulin sensitivity in vivo. The objective of this review is to provide a summary of our current understanding of the role of glucocorticoid-associated insulin resistance, which is important for some cardiac events, and the potential role of galectin in this pathophysiological process.

Measuring Visceral Adipose Tissue Metabolic Activity in Sleep Apnea Utilizing Hybrid 18F-FDG PET/MRI: A Pilot Study

PURPOSE

Visceral adipose tissue (VAT) is proinflammatory and is associated with cardiovascular (CV) disease. We investigated the relationship between obstructive sleep apnea (OSA) and visceral adipose tissue (VAT) metabolic activity in a pilot group of patients using positron-emission tomography/magnetic resonance imaging (PET/MRI) with ¹⁸F-fluorodeoxyglucose (FDG) tracer as a novel marker of adipose tissue inflammation.

PATIENTS AND METHODS

We analyzed patients from an ongoing study, recruiting those with newly diagnosed, untreated OSA (Respiratory Disturbance Index [RDI] ≥ 5), using home sleep apnea testing (WatchPAT-200 Central-Plus). PET/MRI scans were acquired before continuous positive airway pressure (CPAP)-initiation, and after 3 months of CPAP therapy. Adipose tissue metabolic activity (¹⁸F-FDG-uptake) was measured using standardized uptake values (SUV) within the adipose tissue depots. The primary outcome was VAT SUVmean, and secondary outcomes included VAT volume, and subcutaneous adipose tissue (SAT) volume/SUVmean. Reproducibility and reliability of outcome measures were analyzed using intraclass correlation coefficients (ICC). Multivariable linear regression was used to evaluate the association between OSA and primary/secondary outcomes.

RESULTS

Our analytical sample (n = 16) was 81% male (mean age 47 ± 15 years, mean BMI of 29.9 ± 4.8kg/m²). About 56% had moderate to severe OSA (mean RDI 23 ± 6 events/hour), and 50% were adherent to CPAP. We demonstrated excellent inter/intra-rater reliability and reproducibility for the primary and secondary outcomes. Patients with moderate-to-severe OSA had a higher VAT SUV mean compared to those with mild OSA (0.795 ± 0.154 vs 0.602 ± 0.19, p = 0.04). OSA severity was positively associated with VAT SUVmean (primary outcome), adjusted for age and BMI (B [SE] = 0.013 ± 0.005, p = 0.03). Change in VAT volume was inversely correlated with CPAP adherence in unadjusted analysis (B [SE] = -48.4 ± 18.7, p = 0.02).

CONCLUSION

Derangements in VAT metabolic activity are implicated in adverse cardiometabolic outcomes and may be one of the key drivers of CV risk in OSA. Our results are hypothesis-generating, and suggest that VAT should be investigated in future studies using multi-modal imaging to understand its role as a potential mediator of adverse cardiometabolic risk in OSA.

Anthocyanins increase serum adiponectin in newly diagnosed diabetes but not in prediabetes: a randomized controlled trial

Background

Epidemiological studies have suggested that adiponectin is associated with the development of insulin resistance and type 2 diabetes. This study first examined the effect of purified anthocyanins, a group of dietary flavonoids, on serum adiponectin in patients with prediabetes and newly diagnosed diabetes.

Methods

A total of 160 patients with prediabetes (n = 90) or newly diagnosed diabetes (n = 70) were randomly assigned to either the anthocyanins group or the placebo group for 12 weeks of intervention. Serum adiponectin, a set of biomarkers related to glucolipid metabolism, anthropometric parameters, dietary intake and physical activity were measured before and after intervention.

Results

Anthocyanins increased serum adiponectin compared with placebo (net change 0.46 µg/mL, 95% CI [0.03, 0.90], p = 0.038) in the subjects with newly diagnosed diabetes. No significant difference in the change in adiponectin was observed between the two groups either in the overall subjects (0.02 µg/mL [− 0.32, 0.36], p = 0.906) or in prediabetes (− 0.35 µg/mL [− 0.85, 0.16], p = 0.174). Anthocyanins also decreased fasting glucose (− 0.5 mmol/L [− 1, − 0.04], p = 0.035) in the subjects with newly diagnosed diabetes, but no such change was observed in those with prediabetes.

Conclusions

Anthocyanins supplementation for 12 weeks improved serum adiponectin and fasting glucose in patients with newly diagnosed diabetes, but not in patients with prediabetes.

Trial registration

ClinicalTrials.gov, NCT02689765. Registered on 6 February 2016, https://clinicaltrials.gov/ct2/show/NCT02689765.

Effects of the juçara fruit supplementation on metabolic parameters in individuals with obesity: a double-blind randomized controlled trial

Adipose tissue inflammation has been proposed as a central mechanism connecting obesity with its metabolic and vascular complications due to the imbalance in the expression of several hormones and adipokines. Berries rich in polyphenols and unsaturated fatty acids have been able to prevent both obesity and adipose tissue inflammation, improving metabolic functions in human subjects and animal models of obesity. Juçara has been considered a super fruit owing to its nutritional composition and relevant biological activities with an interesting response in animals. Thus, we aimed to verify the potential antiobesogenic effect of juçara supplementation in humans. We conducted a double-blind, placebo-controlled, randomized trial with 35 adults with obesity of both sexes. They were assessed for resting metabolic rate, anthropometry and body composition, blood pressure, metabolic parameters and adipokines. Subsequently, they were randomized into two groups to use or not (placebo) 5 g lyophilized juçara for 6 weeks. Supplementation with juçara was significantly effective in reducing body fat, increasing high-density lipoprotein cholesterol and doubling serum adiponectin. Besides, juçara supplementation, high-density lipoprotein cholesterol and neck circumference were predictors to explain the enhancement in adiponectin. Juçara supplementation was determinant to improve adiponectin levels, and it may be considered a novel strategy for the treatment of obesity-related metabolic diseases.

Adiponectin as a sepsis biomarker in dogs: Diagnostic and prognostic value

BACKGROUND

Adiponectin (ADPN) is an adipocytokine with insulin-sensitizing, vascular-protective, and anti-inflammatory properties for which concentration changes occur in response to inflammation. Little is known about the regulation of ADPN and the impact of this adipocytokine in septic dogs.

OBJECTIVE

We aimed to assess the diagnostic and prognostic value of ADPN vs other traditional acute-phase proteins (APPs), such as albumin (ALB), haptoglobin (HPT), fibrinogen (FBG), ferritin (FRT), and C-reactive protein (CRP) in dogs with naturally acquired sepsis.

METHODS

This prospective observational study included 20 dogs with sepsis, 27 with low-grade systemic inflammation (LGSI), and 18 clinically healthy dogs as controls. For method analyses, plasma samples were obtained from all dogs on admission and then every 24-48 hours until discharge or death in the septic group.

RESULTS

Septic dogs had lower ADPN (2.4 ± 0.46 vs 4.5 ± 0.41mg/L, P < .001) dand ALB (17 ± 1 vs 22 ± 0.8g/L, P = .002), and tended to have higher CRP (87 ± 4.8 vs 73 ± 4.1mg/L, P < .079) concentrations than dogs with LGSI on admission. Only ADPN and ALB were able to successfully discriminate animals with LGSI from those presenting with sepsis with areas under the curve (AUCs) for the receiver operating characteristic (ROC) curves of 0.811 and 0.789, respectively. In the septic group, ADPN concentration did not differ between survivors and non-survivors, either on admission or at discharge or death.

CONCLUSIONS

Although plasma ADPN can be used as a reliable negative APP in dogs with sepsis, further studies are warranted to confirm the usefulness of this biomarker in terms of disease progression and recovery.

The Role of Adipose Tissue in the Pathogenesis and Therapeutic Outcomes of Inflammatory Bowel Disease

Though historically regarded as an inert energy store, adipose tissue is a complex endocrine organ, which is increasingly implicated in the pathogenesis of inflammatory bowel disease (IBD). Accumulating evidence points to visceral adipose tissue and specifically to its mesenteric component, or “creeping fat” as impacting on the disease course through its immunomodulatory properties. On the one hand, mesenteric fat acts as a physical barrier to inflammation and is involved in controlling host immune response to translocation of gut bacteria. On the other hand, however, there exists a strong link between visceral fat and complicated course of the disease with unfavorable therapeutic outcomes. Furthermore, “creeping fat” appears to play different roles in different IBD phenotypes, with the greatest pathogenetic contribution probably to an ileal form of Crohn’s disease. In this review, we summarize and discuss the existing literature on the subject and identify high-priority areas for future research. It may be that a better understanding of the role of mesenteric fat in IBD will determine new therapeutic targets and translate into improved clinical outcomes.

'Beauty and the beast' in infection: How immune-endocrine interactions regulate systemic metabolism in the context of infection

The immune and endocrine systems ensure two vital functions in the body. The immune system protects us from lethal pathogens, whereas the endocrine system ensures proper metabolic function of peripheral organs by regulating systemic homeostasis. These two systems were long thought to operate independently. The immune system uses cytokines and immune receptors, whereas the endocrine system uses hormones to regulate metabolism. However, recent findings show that the immune and endocrine systems closely interact, especially regarding regulation of glucose metabolism. In response to pathogen encounter, cytokines modify responsiveness of peripheral organs to endocrine signals, resulting in altered levels of blood hormones such as insulin, which promotes the ability of the body to fight infection. Here we provide an overview of recent literature describing various mechanisms, which the immune system utilizes to modify endocrine regulation of systemic metabolism. Moreover, we will describe how these immune-endocrine interactions derail in the context of obesity. From a clinical perspective we will elaborate how infection and obesity aggravate the development of metabolic diseases such as diabetes mellitus type 2 in humans. In summary, this review provides a comprehensive overview of immune-induced changes in systemic metabolism following infection, with a focus on regulation of glucose metabolism.

Cardiac Obesity and Cardiac Cachexia: Is There a Pathophysiological Link?

Obesity is a risk factor for cardiometabolic and vascular diseases like arterial hypertension, diabetes mellitus type 2, dyslipidaemia, and atherosclerosis. A special role in obesity-related syndromes is played by cardiac visceral obesity, which includes epicardial adipose tissue and intramyocardial fat, leading to cardiac steatosis; hypertensive heart disease; atherosclerosis of epicardial coronary artery disease; and ischemic cardiomyopathy, cardiac microcirculatory dysfunction, diabetic cardiomyopathy, and atrial fibrillation. Cardiac expression of these changes in any given patient is unique and multimodal, varying in clinical settings and level of expressed changes, with heart failure development depending on pathophysiological mechanisms with preserved, midrange, or reduced ejection fraction. Progressive heart failure with misbalanced metabolic and catabolic processes will change muscle, bone, and fat mass and function, with possible changes in the cardiac fat state from excessive accumulation to reduction and cardiac cachexia with a worse prognosis. The question we address is whether cardiac obesity or cardiac cachexia is to be more feared.

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.

High plasma adiponectin levels are associated with frailty in a general old-old population: The Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians study

AIM

The objective of the present study was to investigate the association between frailty and plasma adiponectin levels in a general population of Japanese older adults.

METHODS

The volunteer older adults, aged approximately 83 years, were recruited randomly from a general population in the Japanese Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians study. We used the modified Cardiovascular Health Study criteria to assess the frailty status of the study participants. The study participants were classified as non-frail, pre-frail and frail according to their physical activities. We compared plasma adiponectin levels among these three groups and applied a multivariate logistic regression analysis including plasma adiponectin levels to clarify the factors associated with frailty status in the cross-sectional design.

RESULTS

The mean age of the participants was 83.1 ± 0.9 years, and 51.8% were men. The frailty index was available to assess 353 participants, of whom 24.6% were classified as non-frail, 62.3% as prefrail and 13.0% as frail. The log-transformed plasma adiponectin levels increased stepwise in the following order: non-frail, pre-frail and frail. A multivariate logistic regression analysis showed that higher plasma adiponectin levels, a higher estimated glomerular filtration rate and lower hemoglobin levels were independent determinants for pre-frail/frail status compared with non-frail status.

CONCLUSIONS

The present study showed that higher plasma adiponectin levels were associated with frailty status in older Japanese adults in the general population. Further longitudinal study is essential to clarify the role of plasma adiponectin in the progression of frailty. Geriatr Gerontol Int 2018; 18: 839-846.

T allele at ADIPOQ rs1501299 G/T polymorphism is more susceptible to the influence of circulating adiponectin on arterial stiffness in nondiabetic men

BACKGROUND

Low adiponectin levels are associated with increased insulin resistance (IR) and arterial stiffness in hypertensive patients, but higher adiponectin levels are also found in heart failure patients. This discrepancy has not been fully resolved, but it may be related to the adiponectin gene (ADIPOQ) which regulates adiponectin production. We aimed to investigate whether the relationship between adiponectin and arterial stiffness is associated with ADIPOQ rs1501299 G/T polymorphism in nondiabetic Korean men.

METHODS

In nondiabetic men without disease (n = 301), anthropometric parameters, lipid profiles, IR, circulating adiponectin, and brachial-ankle pulse wave velocity (baPWV) were measured. rs1501299 G/T polymorphism was also analyzed.

RESULTS

Circulating adiponectin levels were negatively correlated with baPWV and homeostatic model assessment-IR in the T allele carriers (n = 167), but this correlation was not observed in the GG subjects (n = 134). However, a positive correlation between baPWV and IR was observed in the GG subjects, but not in the T carriers. These patterns were maintained after the adjustment for confounding factors. A stepwise linear regression analysis revealed that circulating adiponectin and systolic blood pressure (BP) were the main influencing factors on baPWV levels in T carriers, but systolic BP, IR and age were the main contributors to increased baPWV levels in the GG subjects.

CONCLUSIONS

This study demonstrates that the relationship between circulating adiponectin and arterial stiffness is different according to ADIPOQ rs1501299 G/T polymorphism, and suggests that T allele is more susceptible to the influence of adiponectin on arterial stiffness than GG homozygotes. This information may prove to be useful for personal-based early prevention and management of atherosclerotic risk.

Determination of Highly Sensitive Biological Cell Model Systems to Screen BPA-Related Health Hazards Using Pathway Studio

Bisphenol-A (BPA) is a ubiquitous endocrine-disrupting chemical. Recently, many issues have arisen surrounding the disease pathogenesis of BPA. Therefore, several studies have been conducted to investigate the proteomic biomarkers of BPA that are associated with disease processes. However, studies on identifying highly sensitive biological cell model systems in determining BPA health risk are lacking. Here, we determined suitable cell model systems and potential biomarkers for predicting BPA-mediated disease using the bioinformatics tool Pathway Studio. We compiled known BPA-mediated diseases in humans, which were categorized into five major types. Subsequently, we investigated the differentially expressed proteins following BPA exposure in several cell types, and analyzed the efficacy of altered proteins to investigate their associations with BPA-mediated diseases. Our results demonstrated that colon cancer cells (SW480), mammary gland, and Sertoli cells were highly sensitive biological model systems, because of the efficacy of predicting the majority of BPA-mediated diseases. We selected glucose-6-phosphate dehydrogenase (G6PD), cytochrome b-c1 complex subunit 1 (UQCRC1), and voltage-dependent anion-selective channel protein 2 (VDAC2) as highly sensitive biomarkers to predict BPA-mediated diseases. Furthermore, we summarized proteomic studies in spermatozoa following BPA exposure, which have recently been considered as another suitable cell type for predicting BPA-mediated diseases.

Age and sex differences in serum adiponectin and its association with lipoprotein fractions

Objective The correlation of adiponectin with cholesterol concentration of fractionated lipoproteins has not been well investigated. Methods This study included 174 subjects (79 men and 95 women) without diabetes. The medical record data were investigated retrospectively. The study subjects with adiponectin <8.3, > 8.3 but less 13.9, and ≥ 13.9 were classified into tertile groups: Groups A ( n = 59), B ( n = 58) and C ( n = 57), respectively. Results In women, age and HDL-C were higher in Group C than in Groups A and B, but BMI, TG, IDL-C and VLDL-C were lower in Group C than in Groups A and B. In men, BMI was lower in Group C than in Groups A and B, and HDL-C was higher in Group C than in Groups A and B. In multiple stepwise regression analysis, BMI and HDL-C were significantly correlated with adiponectin in whole, male and female subjects, but TG-rich lipoprotein cholesterol concentrations were not independently correlated. Conclusions HDL-C and BMI were independently correlated with adiponectin in non-diabetic men and women. These results suggest that high adiponectin may play a role in the increased HDL-C concentrations, implicated in the reduction of cardiovascular disease risk, in non-diabetic subjects.

Aberrant Epicardial Adipose Tissue Extracellular Matrix Remodeling in Patients with Severe Ischemic Cardiomyopathy: Insight from Comparative Quantitative Proteomics

There is ample evidence indicating that epicardial adipose tissue (EAT) volume and thickness is positively associated with coronary artery disease (CAD). However, the exact pathological changes in the human EAT after myocardial ischemia remains largely unclear. In the current study, we applied a comparative quantitative proteomics to elucidate the altered biological processes in the EAT of ischemic cardiomyopathy (ICM) patients. A total of 1649 proteins were successfully quantified in our study, among which 165 proteins were significantly changed (ratio <0.8 or >1.2 fold and p < 0.05 in both repetitions) in EAT of ICM individuals. Gene ontology (GO) enrichment analysis revealed that cardiac structure and cellular metabolism were over-represented among these regulated proteins. The hypertrophic cardiomyopathy, adrenergic signaling in cardiomyocytes, extracellular matrix (ECM)-receptor interaction, phagosome, Glycolysis/Gluconeogenesis, and PPAR signaling pathway were highlighted by the KEGG PATHWAY analysis. More importantly, we found that the proteins responsible for extracellular matrix organization were dramatically increased in EAT of ICM patients. In addition, the picrosirius red (PSR) staining results showed that the collagen fiber content was prominently increased, which indicated the EAT of ICM individuals underwent extracellular matrix remodeling and ERK1/2 activation maybe responsible for these pathological changes partially.

Leptin as a cardiovascular risk marker in metabolically healthy obese: Hyperleptinemia in metabolically healthy obese

Adipokines contribute to the inflammatory process which can lead to obesity-associated cardiometabolic complications. Metabolically healthy obese individuals seem to be protected or more resistant to develop these complications and it is intriguing why some individuals develop comorbidities and others do not. Thus, we questioned whether the differences between metabolically healthy and unhealthy obese relied on the alterations in metabolic profile, characterized by serum leptin and adiponectin. A total of 142 obese adults were divided into 2 groups - metabolically healthy obese (MHO) or unhealthy obese (MUO) - and they were evaluated for anthropometric measures, body composition, blood pressure, dietary intakes and plasma levels of leptin and adiponectin. Leptin/adiponectin ratio (L/A) was calculated. Age, BMI and blood pressure were higher in the MUO. No differences in anthropometric measurements, body composition, dietary intake and dietary quality were observed between groups. Leptin were significantly higher in the MUO (53.07 ± 34.56 versus 36.27 ± 24.02 ng/ml in the MHO, r < 0.04). The logistic regression analysis demonstrated that leptin was an important factor associated with not being healthy, independent of age, body weight and BMI. There were no differences between groups for adiponectin and L/A. Leptin correlated positively with body weight (r = 0.25, r < 0.05), BMI (r = 0.38, r < 0.05) and BF (r = 0.74, r < 0.05), and negatively with FFM (r = -0.74, r < 0.05). Our findings suggest that leptin is an important cardiovascular disease marker to obese population and can contribute to evaluate metabolic risks in these individuals.

Protective effect of composite earthworm powder against diabetic complications via increased fibrinolytic function and improvement of lipid metabolism in ZDF rats

Thrombosis is the leading cause of mortality globally. It is not only a complication but also a risk factor for progression of diabetes. However, alternative oral therapies and prophylaxis with less adverse effect for thrombosis have not been well studied. In this study, composite powder containing earthworm (CEP) was used and its fibrinolytic activity was measured. CEP was found to have a high urokinase-type plasminogen activator like activity in an in vitro assay. It also had significantly shortened euglobulin clot lysis time (ECLT) at 4 and 24 h after ingestion in Sprague Dawley rats. Zucker Diabetic Fatty rats were used to assess the effect of CEP on diabetes and diabetic nephropathy. After 10 weeks of feeding, CEP significantly shortened ECLT and attenuated HbA1c, hepatic lipid accumulation, and urinary albumin excretion and improved glomerular mesangial matrix score. Therefore, CEP may have beneficial effects on diabetes and diabetic nephropathy.

Trigonella foenum-graecum water extract improves insulin sensitivity and stimulates PPAR and γ gene expression in high fructose-fed insulin-resistant rats

BACKGROUND

Insulin resistance is the main defect associated with the metabolic syndrome. In obesity, the decreased adiponectin levels and elevation of plasma-free fatty acids are the main factors associated with insulin resistance. In this study, we evaluated the effect of trigonella foenum-graecum (TFG) extract on insulin sensitivity in high fructose-fed insulin-resistant rats.

MATERIALS AND METHODS

Experimental rats were fed with a high fructose diet for eight weeks. After the first six weeks, the animals were treated with trigonella foenum-graecum extract or pioglitazone for two weeks. Serum glucose, triglycerides, cholesterol, and HDL-c were measured. The insulin and adiponectin levels were assayed by the enzyme-linked immunosorbent assay (ELISA), and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was calculated. The plasma-free fatty acid profile was obtained by gas chromatography. PPARγ and GLUT4 gene expression were assessed by real-time polymerase chain reaction (PCR) and western blotting.

RESULTS

In the trigonella foenum-graecum- extract treated group the following results were obtained: Insulin (49.02 ± 6.93 pmol/L), adiponectin (7.1 ± 0.64 μg/ml), and triglycerides (110.3 ± 16.7 mg/dl), which were significantly different and improved compared to the control group (insulin (137 ± 34 pmol/l), adiponectin (3.9 ± 0.15 μg/ml), glucose (187 ± 15 mg/dl), and triglycerides (217 ± 18 mg/dl). Also the PPARγ gene expression was significantly increased compared to the control group.

CONCLUSION

This study demonstrates the beneficial effects of trigonella foenum-graecum extract on insulin resistance in rats fed on a high-fructose diet. At least three mechanisms are involved, including direct insulin-like effect, increase in adiponectin levels, and PPARγ protein expression.

The role of abnormal metabolic conditions on arterial stiffness in healthy subjects with no drug treatment

BACKGROUND

Subjects with abnormal metabolic conditions had increased risk for cardiovascular disease. We investigated the role of abnormal metabolic conditions on arterial stiffness in healthy subjects with no drug treatment.

METHODS

A total 601 subjects (age 48.7 ± 11.8 years, male 46.2 %, hypertension 19.1 %) were enrolled. Major cardiovascular risk factors, metabolic conditions and parameters (pre-diabetes, diabetes mellitus, metabolic syndrome, fasting blood sugar (FBS), glycated hemoglobin), lipid profiles, hsCRP, and brachial ankle pulse wave velocity (baPWV) were measured.

RESULTS

Subjects with metabolic syndrome (n = 200) had higher baPWV than in subjects without metabolic syndrome (n = 401) even after adjustments for age, sex and presence of hypertension (1435.9 ± 212.2 vs. 1336.5 ± 225.0 cm/sec, p < 0.001). The differences of baPWV among normal FBS, prediabetes and diabetes mellitus groups are significant (P for trend = 0.036) by multivariate analysis (adjustments for age, sex, office systolic blood pressure). Subjects with diabetes mellitus (n = 30) had higher baPWV than in subjects with normal FBS (n = 384, 1525 ± 267.1 vs. 1341.5 ± 224.1 cm/sec, P = 0.016 adjustments for age, sex, office systolic blood pressure). BaPWV in subjects with prediabetes (n = 187) was slightly higher, but not statistically significant than in subjects with normal FBS (P = 0.377). Of interest, FBS was one of the independent predictors for increased baPWV (β = 0.809, 95 % CI 0.222-1.397, p = 0.007) by multivariate analysis.

CONCLUSIONS

Subjects with abnormal metabolic conditions have increased arterial stiffness independent of age and BP which may contribute to the development of cardiovascular disease.

Gender-specific associations between ADIPOQ gene polymorphisms and adiponectin levels and obesity in the Jackson Heart Study cohort

BACKGROUND

Despite the important role of adiponectin in regulating general metabolic homeostasis, analysis of genetic determinants of adiponectin and the related cardio-metabolic traits in African American population has been limited and inconsistent. Considering the high genetic admixture of African Americans and thus the important population stratification that may confound the genetic-trait associations, the objective of this work was to perform a comprehensive analysis of the associations between ADIPOQ variants and adiponectin levels and obesity phenotypes in a large African American population from the Jackson Heart Study (JHS) cohort.

METHODS

Genotype data was available for 2968 JHS participants (1131men; 1837women). Single Nucleotide Polymorphisms (SNPs) were selected by a Tag-SNP Approach and literature review. The genotype imputation was performed using IMPUTE2 software and reference phased data from the 1000G project. PLINK software was used for the genetic analysis. Plasma specimens were analyzed by ELISA for adiponectin levels. All analyses were controlled for population stratification assessed by Individual Proportions of European Ancestry (PEA) estimates calculated in HAPMIX using ancestry informative markers (AIMs).

RESULTS

We found a gender-dependent association of some ADIPOQ variants and adiponectin levels. In women four of the studied polymorphisms (rs6444174, rs16861205, rs1403697, rs7641507) were associated with adiponectin levels after Bonferroni correction and controlling for the percentage of PEA, age, annual household income and smoking. These results were consistent with the haplotype analysis. The association between the rs12495941 variant and obesity is modulated by the PEA, so that the relationship between the G allele and a higher incidence of obesity was present in those individuals within the lower PEA group. In addition we found an effect modification of obesity on the association between the ADIPOQ rs6444174 SNP and BMI so that the presence of the T allele was negatively and significantly associated with BMI only in participants with a normal weight.

CONCLUSIONS

In this large African American cohort, ADIPOQ variants were associated with adiponectin levels in a gender-dependent manner and the relationship of some of these variants with obesity and BMI was modulated by the PEA and obesity status respectively. This suggests that the effects of these polymorphisms on adiponectin and obesity phenotypes are subject to a strong interaction with genetic and environmental factors in African American population.

Sex-Specific Effects of Adiponectin on Carotid Intima-Media Thickness and Incident Cardiovascular Disease

BACKGROUND

Plasma adiponectin levels have previously been inversely associated with carotid intima-media thickness (IMT), a marker of subclinical atherosclerosis. In this study, we used a sex-stratified Mendelian randomization approach to investigate whether adiponectin has a causal protective influence on IMT.

METHODS AND RESULTS

Baseline plasma adiponectin concentration was tested for association with baseline IMT, IMT progression over 30 months, and occurrence of cardiovascular events within 3 years in 3430 participants (women, n=1777; men, n=1653) with high cardiovascular risk but no prevalent disease. Plasma adiponectin levels were inversely associated with baseline mean bifurcation IMT after adjustment for established risk factors (β=-0.018, P<0.001) in men but not in women (β=-0.006, P=0.185; P for interaction=0.061). Adiponectin levels were inversely associated with progression of mean common carotid IMT in men (β=-0.0022, P=0.047), whereas no association was seen in women (0.0007, P=0.475; P for interaction=0.018). Moreover, we observed that adiponectin levels were inversely associated with coronary events in women (hazard ratio 0.57, 95% CI 0.37 to 0.87) but not in men (hazard ratio 0.82, 95% CI 0.54 to 1.25). A gene score of adiponectin-raising alleles in 6 loci, reported recently in a large multi-ethnic meta-analysis, was inversely associated with baseline mean bifurcation IMT in men (β=-0.0008, P=0.004) but not in women (β=-0.0003, P=0.522; P for interaction=0.007).

CONCLUSIONS

This report provides some evidence for adiponectin protecting against atherosclerosis, with effects being confined to men; however, compared with established cardiovascular risk factors, the effect of plasma adiponectin was modest. Further investigation involving mechanistic studies is warranted.

Gender difference in adiponectin associated with cardiovascular mortality

Background

It is important to identify cardiovascular diseases in patients at high risk. To include genetics into routine cardiological patients has therefore been discussed recently.

We wanted to evaluate the association between high-molecular weight adiponectin and cardiovascular risk, and secondly in the same population evaluate if specific genotype differences regarding risk could be observed, and thirdly if gender differences could be seen.

Method

Four hundred seventy-six elderly participants recruited from a rural community were included. All participants underwent a clinical examination, echocardiography, and blood sampling and the single nucleotide polymorphism (SNP) (rs266729) of adiponectin was analysed. Follow-up time was 6.7 years.

Results

Those with high serum concentration of adiponectin had a more 2 fold increased cardiovascular risk, and it might be that females exhibits even higher risk where a more than 5 fold increased risk could be seen. The result could be demonstrated even in a multivariate model adjusting for well-known clinical risk factors. However, as the sample size was small the gender differences should be interpreted with caution. In the genotype evaluation the C/C carriers of the female group had a more than 9-fold increased risk of cardiovascular mortality, however the confidence interval was wide. Such genotype difference could not be found in the male group.

Conclusion

High level of adiponectin was associated with increased cardiovascular risk. Also a gender difference in the genotype evaluation could be seen where the C/C carriers obtained higher risk in the female group but not in the male group. Thus, in order to identify patients at risk early, genetic analyses may add to the armamentarium used in the clinical routine. However, information should be regarded as hypothesis generating as the sample size was small and should stimulate further research in individualized cardiovascular prevention and treatment.

Epicardial adipose tissue: far more than a fat depot

Epicardial adipose tissue (EAT) refers to the fat depot that exists on the surface of the myocardium and is contained entirely beneath the pericardium, thus surrounding and in direct contact with the major coronary arteries and their branches. EAT is a biologically active organ that may play a role in the association between obesity and coronary artery disease (CAD). Given recent advances in non-invasive imaging modalities such a multidetector computed tomography (MDCT), EAT can be accurately measured and quantified. In this review, we focus on the evidence suggesting a role for EAT as a quantifiable risk marker in CAD, as well as describe the role EAT may play in the development and vulnerability of coronary artery plaque.

Adiponectin serum levels correlate with insulin resistance in type 2 diabetic patients

The adipose tissue is not only an inert storage depot for lipids, but also it secretes a variety of bioactive molecules, known as adipokines, which affect whole-body homeostasis. Adiponectin is the most abundant of these adipocytokines and is known to have a regulatory effect on the metabolism of glucose and lipid. The main objectives of this study were to evaluate the serum levels of adiponectin and to establish a correlation between adiponectin serum levels and the degree of insulin resistance in type 2 diabetic patients. Eighty participants were enrolled in this study; 61 type 2 diabetic patients and 19 apparently healthy subjects. Serum level of adiponectin was measured by enzyme-linked immunosorbent assay (ELISA) for each participant. Data collection sheet was filled with all required information for each participant. Adiponectin level in the diabetic patients (5.05 ± 2.61 μg/ml) was lower than in non-diabetic healthy controls (5.71 ± 2.35 μg/ml). When the results were compared according to gender, diabetic females showed significantly higher adiponectin levels (5.76 ± 2.64 μg/ml) than diabetic males (4.366 ± 2.43 μg/ml, P = 0.035). In addition, female diabetic patients with abdominal obesity (waist circumference (WC) ⩾ 88 cm) had lower adiponectin levels (5.58 ± 2.58 μg/ml) than diabetic females without abdominal obesity (6.96 ± 3.12 μg/ml). The correlation analysis indicated that adiponectin had a significant positive correlation with age (r = −0.450, P < 0.001). In conclusion, female diabetic patients had a statistically significant higher adiponectin level than male diabetic patients which could indicate a gender effect. Adiponectin levels were inversely related to insulin resistance; as patients with abdominal obesity had lower serum levels of adiponectin.

The association between obesity and fluid intelligence impairment is mediated by chronic low-grade inflammation

Published evidence suggests that obesity impairs cognition. Development of chronic low-grade inflammation (CLGI) represents the earliest consequence of obesity. The present study investigated the association between obesity and fluid intelligence impairment and assessed the potential mediating role of CLGI and psychological (depression/anxiety symptoms), lifestyle (exercise) and physiological (metabolic dysfunction indices) factors in this association. Clinically healthy participants (n 188), grouped as per BMI, underwent cognitive (General Ability Measure for Adults), psychological (Beck Depression Inventory-II and State-Trait Anxiety Inventory) and activity (Godin leisure-time physical activity) measurements. Biochemical parameters included the following: (a) indices of CLGI (high-sensitivity C-reactive protein, erythrocyte sedimentation rate and fibrinogen); (b) insulin resistance (Homeostasis Model Assessment of Insulin Resistance index); (c) adiposity (plasma adiponectin). An inverse association between elevated BMI and fluid intelligence was observed, with obese participants displaying significantly poorer performance compared with age-matched normal-weight peers. Structural equation modelling results were consistent with a negative impact of obesity on cognition that was mediated by CLGI. The results of the present study support the hypothesis that reduced general cognitive ability is associated with obesity, an adverse effect mainly mediated by obesity-associated activation of innate immunity.

Reciprocal Effects of Systemic Inflammation and Brain Natriuretic Peptide on Adiponectin Biosynthesis in Adipose Tissue of Patients With Ischemic Heart Disease

Objective—

To explore the role of systemic inflammation in the regulation of adiponectin levels in patients with ischemic heart disease.

Approach and Results—

In a cross-sectional study of 575 subjects, serum adiponectin was compared between healthy subjects, patients with coronary artery disease with no/mild/severe heart failure (HF), and patients with nonischemic HF. Adiponectin expression and release from femoral, subcutaneous and thoracic adipose tissue was determined in 258 additional patients with coronary artery bypass grafting. Responsiveness of the various human adipose tissue depots to interleukin-6, tumor necrosis factor-α, and brain natriuretic peptide (BNP) was examined by using ex vivo models of human fat. The effects of inducible low-grade inflammation were tested by using the model of Salmonella typhi vaccine-induced inflammation in healthy individuals. In the cross-sectional study, HF strikingly increased adiponectin levels. Plasma BNP was the strongest predictor of circulating adiponectin and its release from all adipose tissue depots in patients with coronary artery bypass grafting, even in the absence of HF. Femoral AT was the depot with the least macrophages infiltration and the largest adipocyte cell size and the only responsive to systemic and ex vivo proinflammatory stimulation (effect reversible by BNP). Low-grade inflammation reduced circulating adiponectin levels, while circulating BNP remained unchanged.

Conclusions—

This study demonstrates the regional variability in the responsiveness of human adipose tissue to systemic inflammation and suggests that BNP (not systemic inflammation) is the main driver of circulating adiponectin in patients with advanced atherosclerosis even in the absence of HF. Any interpretation of circulating adiponectin as a biomarker should take into account the underlying disease state, background inflammation, and BNP levels.

Metabolic effects of the contraceptive skin patch and subdermal contraceptive implant in Mexican women: a prospective study

Background

The contraceptive skin patch (CSP) accepted by the U.S. FDA in 2001 includes ethinylestradiol and norelgestromine, whereas the subdermal contraceptive implant (SCI) has etonogestrel and is also approved by the FDA. In Mexico, both are now widely used for contraception but their effects on Mexican population are unknown. The objective of the study was to evaluate if these treatments induce metabolic changes in a sample of indigenous and mestizo Mexican women.

Methods

An observational, prospective, longitudinal, non-randomized study of women between 18 and 35 years of age assigned to CSP or SCI. We performed several laboratory tests: clinical chemistry, lipid profile, and liver and thyroid function tests. Also, serum levels of insulin, C-peptide, IGF-1, leptin, adiponectin, and C reactive protein were assayed.

Results

Sixty-two women were enrolled, 25 used CSP (0 indigenous; 25 mestizos) and 37 used SCI (18 indigenous; 19 mestizos). Clinical symptoms were relatively more frequent in the SCI group. Thirty-four contraceptive users gained weight without other clinical significant changes. After 4 months of treatment, significant changes were found in some biochemical parameters in both treatment groups. Most were clinically irrelevant. Interestingly, the percentage of users with an abnormal atherogenic index diminished from 75% to 41.6% after follow-up.

Conclusions

The CSP slightly modified the metabolic variables. Most changes were nonsignificant, whereas for SCI users changes were more evident and perhaps beneficial. Results of this attempt to evaluate the effects of contraceptives in mestizo and native-American populations show that clinical symptoms are frequent in Mexican users of CSP and SCI. Although these medications may affect some metabolic variables, these changes seem clinically irrelevant. Induction of abnormalities in other physiological pathways cannot be ruled out.

Adiponectin attenuates the osteoblastic differentiation of vascular smooth muscle cells through the AMPK/mTOR pathway

Vascular calcification is common in patients with peripheral artery diseases and coronary artery diseases. The osteoblastic differentiation of vascular smooth muscle cells (VSMCs) contributes significantly to vascular calcification. Adiponectin has been demonstrated to exert a protective effect in osteoblastic differentiation of VSMCs through regulating mTOR activity. However, the upstream and downstream signaling molecules of adiponectin-regulated mTOR signaling have not been identified in VSMCs with osteoblastic differentiation. In this study, the VSMC differentiation model was established by beta-glycerophosphate (β-GP) induction. The mineralization was identified by Alizarin Red S staining. Protein expression and phosphorylation were detected by Western blot or immunofluorescence. Adiponectin attenuated osteoblastic differentiation and mineralization of β-GP-treated VSMCs. Adiponectin inhibited osteoblastic differentiation of VSMCs through increasing the level of p-AMPKα. Pretreatment of VSMCs with AMPK inhibitor blocked while AMPK activator enhanced the effect of adiponectin on osteoblastic differentiation of VSMCs. Adiponectin upregulated TSC2 expression and downregulated mTOR and S6K1 phosphorylation in β-GP-treated VSMCs. Adiponectin treatment significantly attenuates the osteoblastic differentiation and calcification of VSMCs through modulation of AMPK-TSC2-mTOR-S6K1 signal pathway.

Endothelial wall thickness, cardiorespiratory fitness and inflammatory markers in obese and non-obese adolescents

BACKGROUND

Increased carotid intima-media thickness (c-IMT) is considered a marker of early-onset atherosclerosis and it has been found in obese children and adolescents, but the risk factors associated with this population remain to be elucidated.

OBJECTIVE

To compare and verify the relationship between c-IMT, metabolic profile, inflammatory markers, and cardiorespiratory fitness in obese and non-obese children and adolescents.

METHOD

Thirty-five obese subjects (19 boys) and 18 non-obese subjects (9 boys), aged 10-16 years, were included. Anthropometry, body composition, blood pressure, maximal oxygen consumption (VO2max), and basal metabolic rate were evaluated. Serum glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), blood lipids, C-reactive protein (CRP), and adiponectin were assessed. c-IMT was measured by ultrasound.

RESULTS

The results showed that c-IMT, triglycerides, insulin, HOMA-IR, and CRP values were significantly higher in the obese group than in the non-obese group, and high-density lipoprotein cholesterol (HDL-c), adiponectin, and VO2max values were significantly lower in the obese group than in the non-obese group. The c-IMT was directly correlated with body weight, waist circumference, % body fat, and HOMA-IR and inversely correlated with % free fat mass, HDL-c, and VO2max.

CONCLUSIONS

Our findings show that c-IMT correlates not only with body composition, lipids, insulin resistance, and inflammation but also with low VO2max values in children and adolescents.

Head-to-head comparison of fibrates versus statins for elevation of circulating adiponectin concentrations: a systematic review and meta-analysis

BACKGROUND

Elevation of adiponectin levels is a potential therapeutic tool against cardiovascular and metabolic diseases. Clinical evidence suggests differences between fibrates and statins in improving circulating concentrations of adiponectin.

AIM

To compare the efficacy of fibrates vs. statins on circulating concentrations of adiponectin by meta-analysis of randomized head-to-head trials.

METHODS

A systematic literature search of Medline was conducted to identify randomized head-to-head comparative trials investigating the efficacy of fibrates vs. statins on circulating levels of adiponectin. Inverse variance-weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes in adiponectin concentrations using a random-effects model. Random-effects meta-regression was performed to assess the effect of putative moderators on adiponectin levels.

RESULTS

Six trials with a total of 326 subjects (166 in the fibrate and 160 in the statin group) met the eligibility criteria and were selected for this meta-analysis. The estimated effect size for fibrate versus statin therapy was 0.42 μg/mL (95% CI: -0.34-1.17). This effect size was robust in the leave-one-out sensitivity analysis and not sensitive to any single study. Meta-regression indicated a borderline significant association between duration of treatment and the effect of fibrates vs. statins on adiponectin concentrations (slope: -0.20; 95% CI: -0.41-0.01; p=0.06). However, baseline body mass index, glucose and lipid levels did not predict the effect of fibrate vs. statin therapy on circulating adiponectin concentrations (p>0.05).

CONCLUSIONS

Monotherapy with either fibrates or statins has comparable effects on circulating concentrations of adiponectin. Thus, differential effects of statins and fibrates on the occurrence of cardiovascular events may not be attributed to the corresponding changes in adiponectin levels.

Interactions between vascular wall and perivascular adipose tissue reveal novel roles for adiponectin in the regulation of endothelial nitric oxide synthase function in human vessels

BACKGROUND

Adiponectin is an adipokine with potentially important roles in human cardiovascular disease states. We studied the role of adiponectin in the cross-talk between adipose tissue and vascular redox state in patients with atherosclerosis.

METHODS AND RESULTS

The study included 677 patients undergoing coronary artery bypass graft surgery. Endothelial function was evaluated by flow-mediated dilation of the brachial artery in vivo and by vasomotor studies in saphenous vein segments ex vivo. Vascular superoxide (O2(-)) and endothelial nitric oxide synthase (eNOS) uncoupling were quantified in saphenous vein and internal mammary artery segments. Local adiponectin gene expression and ex vivo release were quantified in perivascular (saphenous vein and internal mammary artery) subcutaneous and mesothoracic adipose tissue from 248 patients. Circulating adiponectin was independently associated with nitric oxide bioavailability and O2(-) production/eNOS uncoupling in both arteries and veins. These findings were supported by a similar association between functional polymorphisms in the adiponectin gene and vascular redox state. In contrast, local adiponectin gene expression/release in perivascular adipose tissue was positively correlated with O2(-) and eNOS uncoupling in the underlying vessels. In ex vivo experiments with human saphenous veins and internal mammary arteries, adiponectin induced Akt-mediated eNOS phosphorylation and increased tetrahydrobiopterin bioavailability, improving eNOS coupling. In ex vivo experiments with human saphenous veins/internal mammary arteries and adipose tissue, we demonstrated that peroxidation products produced in the vascular wall (ie, 4-hydroxynonenal) upregulate adiponectin gene expression in perivascular adipose tissue via a peroxisome proliferator-activated receptor-γ-dependent mechanism.

CONCLUSIONS

We demonstrate for the first time that adiponectin improves the redox state in human vessels by restoring eNOS coupling, and we identify a novel role of vascular oxidative stress in the regulation of adiponectin expression in human perivascular adipose tissue.

Relation of serum adiponectin levels to number of traditional atherosclerotic risk factors and all-cause mortality and major adverse cardiovascular events (from the Copenhagen City Heart Study)

Adiponectin exerts anti-inflammatory and antiatherogenic effects and appears to protect against arteriosclerosis. Accordingly, an association between low concentrations of plasma adiponectin and cardiovascular (CV) disease has been demonstrated in several studies. In contrast, elevated plasma adiponectin has been associated with increased mortality and an increasing number of major adverse CV events (MACE). Because of these conflicting results, the true role of adiponectin remains to be elucidated. In the Copenhagen City Heart Study, we prospectively followed up 5,624 randomly selected men and women from the community without CV disease. Plasma adiponectin was measured at the beginning of the study. The median follow-up time was 7.8 years (interquartile range 7.3 to 8.3). The end point was all-cause mortality (n = 801), and the combined end point was MACE, consisting of CV mortality or nonfatal myocardial infarction or ischemic stroke (n = 502). High adiponectin was inversely associated with an increasing number of traditional CV risk factors (p <0.0001). The geometric mean adiponectin concentrations were 10.0 mg/L (95% confidence interval [CI] 9.7 to 10.4) for persons with no CV risk factors present versus 8.1 mg/L (95% CI 7.8 to 8.4) for persons with 4 CV risk factors. After adjustment for confounding risk factors by Cox regression analysis, adiponectin remained an independent predictor of death and MACE. The hazard ratio for each increase in adiponectin of 5 mg/L for death and MACE was 1.20 (95% CI 1.14 to 1.27; p <0.0001) and 1.14 (95% CI 1.05-1.23; p <0.0001), respectively. In conclusion, an increasing number of risk factors for CV disease is associated with decreased plasma adiponectin. High plasma adiponectin independently predicted death and MACE in a large community-based population. These results have confirmed the dual expression indicated by previous studies.

Elevated endothelin-1 (ET-1) levels may contribute to hypoadiponectinemia in childhood obesity

CONTEXT

Pediatric obesity is associated with endothelial dysfunction and hypoadiponectinemia, but the relationship between these two conditions remains to be fully clarified. Whether enhanced release of endothelin-1 (ET-1) may directly impair adiponectin (Ad) production in obese children is not known.

OBJECTIVE

The aim of the study was to explore whether and how high circulating levels of ET-1 may contribute to impair Ad production, release, and vascular activity.

DESIGN AND PARTICIPANTS

Sixty children were included into obese (Ob; n = 30), overweight (OW; n = 11), and lean (n = 19) groups. Total and high-molecular-weight Ad, ET-1, vascular cell adhesion molecule-1, and von Willebrand factor levels were measured in serum samples. Adipocytes were stimulated with exogenous ET-1 or with sera from lean, OW, and Ob, and Ad production and release measured in the absence or in the presence of ETA (BQ-123) and ETB (BQ-788) receptor blockers, p42/44 MAPK inhibitor PD-98059, or c-Jun NH2-terminal protein kinase inhibitor SP-600125. Vasodilation to Ad was evaluated in rat isolated arteries in the absence or in the presence of BQ-123/788.

RESULTS

Total and high-molecular-weight Ad was significantly decreased and ET-1 levels significantly increased in OW (P < .01) and Ob (P < .001) children. A statistically significant linear regression (P < .01) was found between Ad and ET-1. Exposure of adipocytes to exogenous ET-1 or serum from OW and Ob significantly decreased Ad mRNA and protein levels (P < 0.001). The inhibitory effect of ET-1 on Ad was reverted by BQ-123/788 or PD-98059 but not SP-600125. Ad-mediated vasodilation was further increased in arteries pretreated with BQ-123/788.

CONCLUSIONS

ET-1-mediated inhibition of Ad synthesis via p42/44 MAPK signaling may provide a possible explanation for hypoadiponectinemia in pediatric obesity and contribute to the development of cardiovascular complications.