Role of adiponectin in metabolic and cardiovascular disease

Adiponectin targets the AMPK/mTOR signaling pathway to alleviate cognitive impairment in epilepsy

Among patients with chronic epilepsy, 70‑80% have cognitive impairment. To investigate the relationship between adiponectin (ADPN) and the cognitive level in epilepsy and its mechanism, 20 epileptic patients and 20 healthy controls were included for the assessment of the cognitive level. An ELISA was used to evaluate the serum ADPN level. An epileptic rat model was established and treated with AdipoRon, an ADPN receptor (AdipoR) agonist, which binds to AdipoR1 and AdipoR2. The Morris water maze test was used to assess the cognitive function of rats, and the expression levels of the synapsis‑associated proteins postsynaptic density protein 95 (PSD95), synaptosomal associated protein 25 (SNAP25) and synaptophysin (SYP), as well as AMP‑activated protein kinase (AMPK), mTOR, phosphorylated (p‑)AMPK and p‑mTOR were determined by immunoblotting. Serum ADPN levels were positively correlated with the Montreal cognitive assessment score. AdipoRon improved the cognitive function of epileptic rats, maintained the structural integrity of hippocampal neurons and reduced neuronal damage. It also promoted the mRNA expression of AdipoR1 and AdipoR2 in the hippocampus. Furthermore, AdipoRon increased the expression of the synapsis‑associated proteins PSD95, SNAP25 and SYP by activating the AMPK/mTOR signaling pathway. ADPN improved cognitive impairment in epilepsy by targeting the AMPK/mTOR signaling pathway, providing novel insights for the treatment of epilepsy.

Deciphering the potential of Cymbopogon citratus (DC.) Stapf as an anti-obesity agent: phytochemical profiling, in vivo evaluations and molecular docking studies

Based on its anti-inflammatory and antioxidant properties, Cymbopogon citratus (DC) Stapf is commonly used in traditional and modern medicine to cure different diseases. The present study investigates the potential of C. citratus organic extract as an anti-obesity drug in a HCHFD (high-carbohydrate, high-fat diet) model for obese rats. Its negative hypolipidemic effect has been confirmed through biochemical and histological methods. Fifty male albino rats were randomly divided into five groups (10 rats each) Group I (Control group), Group II (HCHFD group), Group III (C. citratus group), Group IV (HCHFD + C. citratus group) and Group V (HCHFD + Orlistat group). Serum glucose levels and lipid profiles were quantified using a spectrophotometer. Insulin, apelin, and adiponectin parameters were measured using ELISA (enzyme-linked immunosorbent assay) kits, while real-time PCR following extraction and purification was used for apelin, apelin receptor genes (APJ), and adiponectin gene expression evaluation. Besides, C. citratus methanolic extract was subjected to untargeted metabolic profiling via RP-HPLC-QTOF-MS and MS/MS, disclosing the presence of 52 secondary metabolites where they mainly belonged to phenolic compounds viz., flavones and hydroxycinnamic acids, among other metabolites with predominance of derivatives of luteolin and O-coumaroyl-O-feruloylglycerol. Our findings were further strengthened by computational-based virtual screening protocols that included molecular docking (MDock) and Structure-Activity Relationships (SARs). The MDock studies revealed that the three main flavone-containing metabolites, each with a luteolin C6-glycosylation core featuring two sugar units (16, 25, and 31), outperformed the positive control (8EH, a triazole derivative) known to bind to the APJ protein. These metabolites exhibited exceptional binding affinities, with estimated free binding energy (ΔGB) values of -9 kcal mol-1 or lower, likely due to potential hydrogen bond interactions with the Arg168 residue of the APJ protein. Additionally, the pharmacokinetic, physicochemical, and toxicity profiles of the 11 major metabolites from C. citratus leaf extract were assessed, revealing a profile like that of the positive control in the three selected flavone metabolites. Based on the acquired data, it can be concluded that C. citratus shows strong potential as a hypolipidemic agent and could play a significant role in managing obesity and mitigating its associated complications.

Obesity and diabetes in heart disease in women

Heart disease remains a major health threat in women. Cardiometabolic risk factors such as obesity and diabetes differentially and adversely impact heart disease risk. Although obstructive coronary artery disease is an important cause of ischemic heart disease in women and is prognostic, women are more likely to have angina and myocardial ischemia without obstructive atherosclerosis, which has been attributed to coronary microvascular dysfunction (CMD). Heart failure with preserved ejection fraction (HFpEF) is another condition that predominates in women. CMD and HFpEF are both associated with cardiometabolic risk factors that are prevalent in women. Women are also more likely to have additional risk-enhancing conditions such as autoimmune dysfunction, chronic inflammation, and sex-specific hormonal factors that adversely influence risk. In this review, we focus on cardiometabolic risk factors of obesity and diabetes in heart disease in women, including ischemic heart disease from CMD, HFpEF, and arrythmias. Team-based care to focus on cardiometabolic risk reduction is needed to alter adverse heart disease outcomes in women. Identification, education, treatment, and active surveillance of these dysmetabolic risk factors are imperative in the primary and secondary prevention of heart disease in women.

Role of Perturbated Hemostasis in MASLD and Its Correlation with Adipokines

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to rise, making it one of the most prevalent chronic liver disorders. MASLD encompasses a range of liver pathologies, from simple steatosis to metabolic dysfunction-associated steatohepatitis (MASH) with inflammation, hepatocyte damage, and fibrosis. Interestingly, the liver exhibits close intercommunication with fatty tissue. In fact, adipose tissue could contribute to the etiology and advancement of MASLD, acting as an endocrine organ that releases several hormones and cytokines, with the adipokines assuming a pivotal role. The levels of adipokines in the blood are altered in people with MASLD, and recent research has shed light on the crucial role played by adipokines in regulating energy expenditure, inflammation, and fibrosis in MASLD. However, MASLD disease is a multifaceted condition that affects various aspects of health beyond liver function, including its impact on hemostasis. The alterations in coagulation mechanisms and endothelial and platelet functions may play a role in the increased vulnerability and severity of MASLD. Therefore, more attention is being given to imbalanced adipokines as causative agents in causing disturbances in hemostasis in MASLD. Metabolic inflammation and hepatic injury are fundamental components of MASLD, and the interrelation between these biological components and the hemostasis pathway is delineated by reciprocal influences, as well as the induction of alterations. Adipokines have the potential to serve as the shared elements within this complex interrelationship. The objective of this review is to thoroughly examine the existing scientific knowledge on the impairment of hemostasis in MASLD and its connection with adipokines, with the aim of enhancing our comprehension of the disease.

Alcohol and Heart Failure

Alcohol is the most frequently consumed toxic substance in the world and remains a major global public health issue, with one in three adults consuming it worldwide. Alcohol use is a leading risk factor for disease, contributing to over 60 acute and chronic health conditions, with a particularly complex association with cardiovascular disease. Chronic excessive alcohol consumption is associated with a range of cardiac complications, including decreased myocardial contractility, hypertension, arrhythmias, MI and heart failure. However, low-level alcohol consumption is believed to have a protective effect against ischaemic heart disease and diabetes. In most cohort studies, small to moderate amounts of alcohol consumption have not been linked to heart failure, indicating a threshold effect of alcohol with individual (possibly genetic) predisposition rather than a continuous effect of exposure. This review article explores the potential benefits of alcohol on the heart, the association between alcohol use and alcoholic cardiomyopathy and the epidemiology, clinical correlates and management of alcoholic cardiomyopathy.

Soluble Fiber Effect on Human Serum Leptin and Adiponectin: A Systematic Review and Dose-Response Meta-Analysis

Literature showed that soluble fiber has beneficial effects on cardiometabolic risk factors and leptin and adiponectin serum levels. Our aim in this meta-analysis was to determine the effect of soluble fiber supplementation on leptin and adiponectin serum levels. A systematic search was conducted using PubMed, Scopus, and ISI Web of Science for eligible trials up to December 2021. A random-effects model was used to pool calculated effect sizes. Our analysis showed that soluble fiber supplementation did not significantly affect adiponectin (standardized mean difference [SMD], -0.49 Hedges's, 95% confidence interval [CI], -1.20, 0.21, p value = 0.167; I2 = 95.4, p value < 0.001) and leptin (SMD, -0.8 Hedges's, 95% CI, -1.70, 0.08, p value = 0.076; I2 = 94.6, p value < 0.001) concentrations in comparison with placebo. However, in the subgroup, soluble fiber supplementation had a significant improvement in leptin concentration in overweight and obese patients (SMD, -0.22 Hedges's, 95% CI, -0.43, -0.01, p value = 0.048) and a non-significant beneficial effect in adiponectin level in female (SMD, 0.29 Hedges's, 95% CI, -0.13, 0.71, p value = 0.183) and diabetic patients (SMD, 0.32 Hedges's, 95% CI, -0.67, 1.32, p value = 0.526). A non-linear association between soluble fiber dosage and adiponectin (pnon-linearity < 0.001) was observed. Soluble fiber supplementation could not change the circulatory leptin and adiponectin levels. However, beneficial effects were seen in overweight and obese leptin, and increases in adiponectin may also be observed in female and diabetic patients. Further studies are needed to confirm this results.

Metabolically healthy obesity: Misleading phrase or healthy phenotype?

Obesity is a heterogenous condition with multiple different phenotypes. Among these a particular subtype exists named as metabolically healthy obesity (MHO). MHO has multiple definitions and its prevalence varies according to study. The potential mechanisms underlying the pathophysiology of MHO include the different types of adipose tissue and their distribution, the role of hormones, inflammation, diet, the intestinal microbiota and genetic factors. In contrast to the negative metabolic profile associated with metabolically unhealthy obesity (MUO), MHO has relatively favorable metabolic characteristics. Nevertheless, MHO is still associated with many important chronic diseases including cardiovascular disease, hypertension, type 2 diabetes, chronic kidney disease as well as certain types of cancer and has the risk of progression into the unhealthy phenotype. Therefore, it should not be considered as a benign condition. The major therapeutic alternatives include dietary modifications, exercise, bariatric surgery and certain medications including glucagon-like peptide-1 (GLP-1) analogs, sodium-glucose cotransporter-2 (SGLT-2) inhibitors and tirzepatide. In this review, we discuss the significance of MHO while comparing this phenotype with MUO.

The negative association of lower body fat mass with cardiometabolic disease risk factors is partially mediated by adiponectin

Gluteofemoral fat correlates negatively with a number of cardiometabolic disease risk factors, but the mechanisms involved in these relationships are unknown. The aim of this study was to test the hypothesis that gluteofemoral fat attenuates the risk of cardiometabolic disease by increasing blood adiponectin levels. This was a cross-sectional study in which arm, leg, gluteofemoral, abdominal s.c. and visceral fat levels were measured by dual-energy X-ray absorptiometry in 648 African females. Fasting serum adiponectin, lipid, insulin and plasma glucose levels and blood pressure were measured. Relationships between variables were analysed using multivariable linear regression and structural equation modelling. Adiponectin correlated positively (β = 0.45, P < 0.0001) with gluteofemoral fat in a multivariable regression model that included age, height, and arm, s.c. and visceral fat levels. In further regression models, there was a negative correlation of gluteofemoral fat with fasting glucose (β = -0.28; P < 0.0001) and triglyceride levels (β = -0.29; P < 0.0001) and insulin resistance (HOMA; β = -0.26; P < 0.0001). Structural equation modelling demonstrated that adiponectin mediated 20.7% (P < 0.01) of the association of gluteofemoral fat with insulin resistance and 16.1% (P < 0.01) of the association with triglyceride levels but only 6.67% (P = 0.31) of the association with glucose levels. These results demonstrate that gluteofemoral and leg fat are positively associated with adiponectin levels and that the negative association of lower body fat with insulin resistance and triglyceride levels may partially be mediated by this adipokine. Further studies are required to determine other factors that mediate the effect of lower body fat on cardiometabolic disease risk factors.

Developmental exposure to indoor flame retardants and hypothalamic molecular signatures: Sex-dependent reprogramming of lipid homeostasis

Polybrominated diphenyl ethers (PBDEs) are a class of flame-retardant organohalogen pollutants that act as endocrine/neuroendocrine disrupting chemicals (EDCs). In humans, exposure to brominated flame retardants (BFR) or other environmentally persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and novel organophosphate flame retardants has been associated with increasing trends of diabetes and metabolic disease. However, the effects of PBDEs on metabolic processes and their associated sex-dependent features are poorly understood. The metabolic-disrupting effects of perinatal exposure to industrial penta-PBDE mixture, DE-71, on male and female progeny of C57BL/6N mouse dams were examined in adulthood. Dams were exposed to environmentally relevant doses of PBDEs daily for 10 weeks (p.o.): 0.1 (L-DE-71) and 0.4 mg/kg/d (H-DE-71) and offspring parameters were compared to corn oil vehicle controls (VEH/CON). The following lipid metabolism indices were measured: plasma cholesterol, triglycerides, adiponectin, leptin, and liver lipids. L-DE-71 female offspring were particularly affected, showing hypercholesterolemia, elevated liver lipids and fasting plasma leptin as compared to same-sex VEH/CON, while L- and H-DE-71 male F1 only showed reduced plasma adiponectin. Using the quantitative Folch method, we found that mean liver lipid content was significantly elevated in L-DE-71 female offspring compared to controls. Oil Red O staining revealed fatty liver in female offspring and dams. General measures of adiposity, body weight, white and brown adipose tissue (BAT), and lean and fat mass were weighed or measured using EchoMRI. DE-71 did not produce abnormal adiposity, but decreased BAT depots in L-DE-71 females and males relative to same-sex VEH/CON. To begin to address potential central mechanisms of deregulated lipid metabolism, we used RT-qPCR to quantitate expression of hypothalamic genes in energy-regulating circuits that control lipid homeostasis. Both doses of DE-71 sex-dependently downregulated hypothalamic expression of Lepr, Stat3, Mc4r, Agrp, Gshr in female offspring while H-DE-71 downregulated Npy in exposed females relative to VEH/CON. In contrast, exposed male offspring displayed upregulated Stat3 and Mc4r. Intestinal barrier integrity was measured using FITC-dextran since it can lead to systemic inflammation that leads to liver damage and metabolic disease, but was not affected by DE-71 exposure. These findings indicate that maternal transfer of PBDEs disproportionately endangers female offspring to lipid metabolic reprogramming that may exaggerate risk for adult metabolic disease.

Traditional and Emerging Sex-Specific Risk Factors for Cardiovascular Disease in Women

Cardiovascular disease (CVD) remains a major health threat in women. While traditional CVD risk factors such as hypertension, hyperlipidemia, diabetes, and smoking have been recognized for over 50 years, optimal control of these risk factors remains a major challenge. Unique sex-specific risk factors such as adverse pregnancy outcomes, premature menopause and low estrogen states, and chronic autoimmune inflammatory disorders also contribute to increased CVD risk in women. In addition, psychological risk factors such as stress, depression, and social determinants of health may have a disproportionately adverse impact in women. An improved understanding of traditional and emerging sex-specific CVD risk factors and management of modifiable factors is critical for clinicians who provide care for women. Early recognition and treatment of risk factors may alter the trajectory of adverse CVD events. A multi-disciplinary approach with team-based care involving multiple specialists and improved, targeted educational efforts are needed to reduce CVD risk factors and its adverse consequences in women.

Potential Therapeutic Agents That Target ATP Binding Cassette A1 (ABCA1) Gene Expression

The cholesterol efflux protein ATP binding cassette protein A1 (ABCA) and apolipoprotein A1 (apo A1) are key constituents in the process of reverse-cholesterol transport (RCT), whereby excess cholesterol in the periphery is transported to the liver where it can be converted primarily to bile acids for either use in digestion or excreted. Due to their essential roles in RCT, numerous studies have been conducted in cells, mice, and humans to more thoroughly understand the pathways that regulate their expression and activity with the goal of developing therapeutics that enhance RCT to reduce the risk of cardiovascular disease. Many of the drugs and natural compounds examined target several transcription factors critical for ABCA1 expression in both macrophages and the liver. Likewise, several miRNAs target not only ABCA1 but also the same transcription factors that are critical for its high expression. However, after years of research and many preclinical and clinical trials, only a few leads have proven beneficial in this regard. In this review we discuss the various transcription factors that serve as drug targets for ABCA1 and provide an update on some important leads.

Adiponectin System (Rescue Hormone): The Missing Link between Metabolic and Cardiovascular Diseases

The adipose tissue, regardless of its role in generating and storing energy, acts as a key player as an endocrine tissue, producing a wide scale of cytokines/hormones called adipokines. Adipokines such as leptin, resistin, visfatin and osteopontin own pro-inflammatory effects on the cardiovascular system in some cases. In contrast, some adipokines have cardioprotective and anti-inflammatory impacts including adiponectin, omentin, and apelin. One of the key adipokines is adiponectin, the abundant peptide regulating hormone that is released mainly by adipocytes and cardiomyocytes as well as by endothelial and skeletal cells. It acts through two main receptors: AdipoR1 and AdipoR2, forming the "Adiponectin system" which effectively exerts its cellular mechanisms and responses in target cells. It regulates various metabolic processes, while adiponectin is the adipocyte hormone known for its cardioprotective impact in clinical and experimental research. It is also a well-effector metabolic adipokine, since weight loss or diet restriction show a link with rises in adiponectin concentrations, which is accompanied with increasing insulin sensitivity, glucose, and lipids-regulation via adiponectin's antioxidant, anti-inflammatory, anti-fibrotic actions. The high adiponectin level made it an attractive player in developing therapeutical treatments for metabolic syndromes and cardiovascular disease. The elevated plasma levels of adiponectin are mostly attributed to its benefits on cardio-metabolism. In some cases, adiponectin has been paradoxically accompanied with elevated risk of cardiovascular disease, so higher adiponectin concentration is a marker of poor prediction. Thus, the adiponectin system is attractive to researchers as a biomarker of heart disease advancement and a predictor of prognosis during the term of some cardiovascular diseases and its mechanical functions in Hypertension and diabetic patients. This review highlights the physiological roles of adiponectin as an anti-inflammatory and cardioprotective hormone as well as how it plays as a biomarker and potential therapeutic tool in the cardiovascular system in adult, children, and adolescents. The adiponectin system may be seen as a rescue hormone aiding in remodeling of the cardiovascular system on both cellular and molecular levels. The paradox role of adiponectin relevant to cardiovascular mortality should be taken into consideration.

Diabetic cardiomyopathy and inflammation: development of hostile microenvironment resulting in cardiac damage

Diabetes mellitus is emerging as a major risk factor for heart failure. Diabetic cardiomyopathy is defined as a myocardial dysfunction that is not caused by underlying hypertension or coronary artery disease. Studies about clinical features, natural history and outcomes of the disease are few and often conflicting, because a universally accepted operative definition of diabetic cardiomyopathy is still lacking. Hyperglycemia and related metabolic and endocrine disorders are the triggering factors of myocardial damage in diabetic cardiomyopathy through multiple mechanisms. Among these mechanisms, inflammation has a relevant role, similar to other chronic myocardial disease, such as hypertensive or ischemic heart disease. A balance between inflammatory damage and healing processes is fundamental for homeostasis of myocardial tissue, whereas diabetes mellitus produces an imbalance, promoting inflammation and delaying healing. Therefore, diabetes-related chronic inflammatory state can produce a progressive qualitative deterioration of myocardial tissue, which reflects on progressive left ventricular functional impairment, which can be either diastolic, with prevalent myocardial hypertrophy, or systolic, with prevalent myocardial fibrosis. The aim of this narrative review is to summarize the existing evidence about the role of inflammation in diabetic cardiomyopathy onset and development. Ultimately, potential pharmacological strategies targeting inflammatory response will be reviewed and discussed.

Pathophysiological Consequences of At-Risk Alcohol Use; Implications for Comorbidity Risk in Persons Living With Human Immunodeficiency Virus

At-risk alcohol use is a significant risk factor associated with multisystemic pathophysiological effects leading to multiorgan injury and contributing to 5.3% of all deaths worldwide. The alcohol-mediated cellular and molecular alterations are particularly salient in vulnerable populations, such as people living with HIV (PLWH), diminishing their physiological reserve, and accelerating the aging process. This review presents salient alcohol-associated mechanisms involved in exacerbation of cardiometabolic and neuropathological comorbidities and their implications in the context of HIV disease. The review integrates consideration of environmental factors, such as consumption of a Western diet and its interactions with alcohol-induced metabolic and neurocognitive dyshomeostasis. Major alcohol-mediated mechanisms that contribute to cardiometabolic comorbidity include impaired substrate utilization and storage, endothelial dysfunction, dysregulation of the renin-angiotensin-aldosterone system, and hypertension. Neuroinflammation and loss of neurotrophic support in vulnerable brain regions significantly contribute to alcohol-associated development of neurological deficits and alcohol use disorder risk. Collectively, evidence suggests that at-risk alcohol use exacerbates cardiometabolic and neurocognitive pathologies and accelerates biological aging leading to the development of geriatric comorbidities manifested as frailty in PLWH.

Gender difference in the relationship between lipid accumulation product index and pulse pressure in nondiabetic Korean adults: The Korean National Health and Nutrition Examination Survey 2013-2014

The present study was conducted to assess the association between the lipid accumulation product index (LAP) and pulse pressure (PP) by gender in nondiabetic Korean adults. This study used the data of 8,240 nondiabetic adults (3,577 men and 4,663 women) aged ≥ 20 years from the Korean National Health and Nutrition Examination Survey 2013-2014. Key findings from the study were as follows: first, the mean values of age for the overall population, men, and women were 49.59 ± 15.73 years, 49.26 ± 16.04 years, and 49.85 ± 15.47 years, respectively. Second, in women (n = 4,663), after adjustment for related variables and with quartile 1 of LAP as a reference, the odds ratios (ORs) of high PP (PP > 60 mmHg) were significantly higher in quartile 3 [1.735 (95% confidence interval [CI], 1.064-2.831)] and quartile 4 of LAP [2.271 (95% CI, 1.325-3.893)]. Third, high PP in men (n = 3,577) was not associated with the quartiles of LAP. Forth, after adjustment for related variables, the PP level was positively associated with the quartiles of LAP in women (p < .001) but not in men (p = .400). PP was positively associated with LAP in nondiabetic Korean women but not in men.

The adiponectin signalling pathway - A therapeutic target for the cardiac complications of type 2 diabetes?

Diabetes is associated with an increased risk of heart failure (HF). This is commonly termed diabetic cardiomyopathy and is often characterised by increased cardiac fibrosis, pathological hypertrophy, increased oxidative and endoplasmic reticulum stress as well as diastolic dysfunction. Adiponectin is a cardioprotective adipokine that is downregulated in settings of type 2 diabetes (T2D) and obesity. Furthermore, both adiponectin receptors (AdipoR1 and R2) are also downregulated in these settings which further results in impaired cardiac adiponectin signalling and reduced cardioprotection. In many cardiac pathologies, adiponectin signalling has been shown to protect against cardiac remodelling and lipotoxicity, however its cardioprotective actions in T2D-induced cardiomyopathy remain unresolved. Diabetic cardiomyopathy has historically lacked effective treatment options. In this review, we summarise the current evidence for links between the suppressed adiponectin signalling pathway and cardiac dysfunction, in diabetes. We describe adiponectin receptor-mediated signalling pathways that are normally associated with cardioprotection, as well as current and potential future therapeutic approaches that could target this pathway as possible interventions for diabetic cardiomyopathy.

Association of Adiponectin, Leptin and Resistin Plasma Concentrations with Echocardiographic Parameters in Patients with Coronary Artery Disease

The imbalanced network of adipokines may contribute to the development of systemic low-grade inflammation, metabolic diseases and coronary artery disease (CAD). In the last decade, three classic adipokines—adiponectin, leptin and resistin—have been of particular interest in studies of patients with CAD due to their numerous properties in relation to the cardiovascular system. This has directed our attention to the association of adipokines with cardiac structure and function and the development of heart failure (HF), a common end effect of CAD. Thus, the purpose of this study was to analyse the associations of plasma concentrations of adiponectin, leptin and resistin with parameters assessed in the echocardiographic examinations of CAD patients. The presented study enrolled 167 Caucasian patients (133 male; 34 female) with CAD. Anthropometric, echocardiographic and basic biochemical measurements, together with plasma concentrations of adiponectin, leptin and resistin assays, were performed in each patient. Adiponectin concentrations were negatively associated with left ventricular ejection fraction (LVEF) and shortening fraction (LVSF), and positively associated with mitral valve E/A ratio (E/A), left ventricular end-diastolic volume (LVEDV), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter LVESD, and left atrium diameter (LAD). Resistin concentrations were negatively associated with E/A. Leptin concentrations, although correlated with HF severity assessed by the New York Heart Association (NYHA) Functional Classification, were not independently associated with the echocardiographic parameters of cardiac structure or function. In conclusion, adiponectin and resistin, but not leptin, are associated with the echocardiographic parameters of cardiac remodelling and dysfunction. These associations suggest that adiponectin and resistin might be involved in mechanisms of cardiac remodelling or compensative response. We also suggest the possible benefits of adiponectin and resistin level measurements in the monitoring of patients with CAD.

AdipoRon: A Novel Insulin Sensitizer in Various Complications and the Underlying Mechanisms: A Review

BACKGROUND

AdipoRon is the first synthetic analog of endogenous adiponectin, an adipose tissue-derived hormone. AdipoRon possesses pharmacological properties similar to adiponectin and its ability to bind and activate the adipoR1 and adipoR2 receptors makes it a suitable candidate for the treatment of a multitude of disorders.

OBJECTIVE

In the present review, an attempt was made to compile and discuss the efficacy of adipoRon against various disorders.

RESULTS

AdipoRon is a drug that acts not only in metabolic diseases but in other conditions unrelated to energy metabolism. It is well- reported that adipoRon exhibits strong anti-obesity, anti-diabetic, anticancer, anti-depressant, anti-ischemic, anti-hypertrophic properties and also improves conditions like post-traumatic stress disorder, anxiety, and systemic sclerosis.

CONCLUSION

A lot is known about its effects in experimental systems, but the translation of this knowledge to the clinic requires studies which, for many of the potential target conditions, have yet to be carried out. The beneficial effects of AdipoRon in novel clinical conditions will suggest an underlying pathophysiological role of adiponectin and its receptors in previously unsuspected settings.

AdipoRon Attenuates Hypertension-Induced Epithelial-Mesenchymal Transition and Renal Fibrosis via Promoting Epithelial Autophagy

Hypertension-induced epithelial-mesenchymal transition (EMT) is a major mechanism of renal fibrosis. Adiponectin protects against hypertension-induced target organ damage. AdipoRon is an orally active synthetic adiponectin receptor agonist. However, it is unclear whether AdipoRon could attenuate EMT and renal fibrosis in hypertensive mice. C57BJ/6J mice were utilized to induce DOCA-salt-sensitive hypertensive model. Hypertension results in an altered adiponectin expression and promotes EMT in the kidney. In vitro, AdipoRon inhibits aldosterone (Aldo)-induced EMT and promotes autophagic flux in HK-2 epithelial cells. Mechanically, AdipoRon activates AMPK/ULK1 pathway in epithelial cells. Blockade of AMPK activation, as well as inhibition of autophagy, blocks the effects of AdipoRon on Aldo-induced EMT. Moreover, AdipoRon treatment promotes autophagy and improves renal fibrosis in DOCA-salt-hypertensive mice. Our data suggest that AdipoRon could be a potential therapeutic option to prevent renal fibrosis in hypertensive patients. Graphical abstract.

Adiponectin: Structure, Physiological Functions, Role in Diseases, and Effects of Nutrition

Adiponectin (a protein consisting of 244 amino acids and characterized by a molecular weight of 28 kDa) is a cytokine that is secreted from adipose tissues (adipokine). Available evidence suggests that adiponectin is involved in a variety of physiological functions, molecular and cellular events, including lipid metabolism, energy regulation, immune response and inflammation, and insulin sensitivity. It has a protective effect on neurons and neural stem cells. Adiponectin levels have been reported to be negatively correlated with cancer, cardiovascular disease, and diabetes, and shown to be affected (i.e., significantly increased) by proper healthy nutrition. The present review comprehensively overviews the role of adiponectin in a range of diseases, showing that it can be used as a biomarker for diagnosing these disorders as well as a target for monitoring the effectiveness of preventive and treatment interventions.

Gender dependent differences in lipid metabolism in individuals with type 2 diabetes mellitus

Aim

The present study investigates gender dependent effects of insulin resistance on lipid profile and adipocytokines in individuals with diabetes receiving oral antidiabetic drugs (OADs). The aim was also to reveal the changes in the expression of genes involved in lipid metabolism and inflammation.

Methods

Lipid profile, adipocytokine levels and homeostatic model assessment of insulin resistance (HOMA-IR) was assessed in 100 patients with diabetes (M = 43, F = 57) matched for age and gender with healthy individuals (M = 45, F = 55). The expression pattern of genes was analyzed by quantitative real time PCR.

Results

Males consuming metformin with other drugs exhibited a positive association between HOMA-IR and cholesterol, triglyceride and very low density lipoprotein (VLDL). Females consuming only metformin and metformin with other drugs, showed a positive association of HOMA-IR with cholesterol and a negative association with adiponectin. In males and females with diabetes, a comparable expression of peroxisome proliferator activated receptor γ (PPARγ) while higher expression of sterol regulatory element binding protein 1 (SREBP1) was observed. Expression of fatty acid synthase (FAS), long chain acyl CoA Synthetases (ACSL), malonyl-CoA-acyl carrier protein transacylase (MCAT) and nuclear factor kappa β (NFkβ) was higher in men with diabetes than healthy males. Expression of tumor necrosis factor α (TNF-α) was higher in males and females with diabetes than respective healthy genders.

Conclusion

Insulin resistance adversely affects lipid profile, adipocytokines in males with type 2 diabetes. Expression of genes involved in lipid metabolism and inflammation is found to be undesirably and differentially altered in both the genders.

Involvement of Essential Signaling Cascades and Analysis of Gene Networks in Diabesity

(1) Aims: Diabesity, defined as diabetes occurring in the context of obesity, is a serious health problem that is associated with an increased risk of premature heart attack, stroke, and death. To date, a key challenge has been to understand the molecular pathways that play significant roles in diabesity. In this study, we aimed to investigate the genetic links between diabetes and obesity in diabetic individuals and highlight the role(s) of shared genes in individuals with diabesity. (2) Methods: The interactions between the genes were analyzed using the Search Tool for the Retrieval of Interacting Genes (STRING) tool after the compilation of obesity genes associated with type 1 diabetes (T1D), type 2 diabetes (T2D), and maturity-onset diabetes of the young (MODY). Cytoscape plugins were utilized for enrichment analysis. (3) Results: We identified 546 obesity genes that are associated with T1D, T2D, and MODY. The network backbone of the identified genes comprised 514 nodes and 4126 edges with an estimated clustering coefficient of 0.242. The Molecular Complex Detection (MCODE) generated three clusters with a score of 33.61, 16.788, and 6.783, each. The highest-scoring nodes of the clusters were AGT, FGB, and LDLR genes. The genes from cluster 1 were enriched in FOXO-mediated transcription of oxidative stress, renin secretion, and regulation of lipolysis in adipocytes. The cluster 2 genes enriched in Src homology 2 domain-containing (SHC)-related events triggered by IGF1R, regulation of lipolysis in adipocytes, and GRB2: SOS produce a link to mitogen-activated protein kinase (MAPK) signaling for integrins. The cluster 3 genes ere enriched in IGF1R signaling cascade and insulin signaling pathway. (4) Conclusion: This study presents a platform to discover potential targets for diabesity treatment and helps in understanding the molecular mechanism.

Fufang-Zhenzhu-Tiaozhi capsule ameliorates rabbit's iliac artery restenosis by regulating adiponectin signaling pathway

BACKGROUND AND PURPOSE

Fufang-Zhenzhu-Tiaozhi Capsule (FTZ), a traditional Chinese medicine, has been shown obvious effects on the treatment of dyslipidemia and atherosclerosis. The aim of this study was to evaluate whether FTZ can ameliorate rabbit iliac artery restenosis after angioplasty by regulating adiponectin signaling pathway.

EXPERIMENTAL APPROACH

The rabbit iliac artery restenosis model was established through percutaneous iliac artery transluminal balloon angioplasty and a high-fat diet. Twenty eight male New Zealand rabbits (8-week-old) were divided into sham operation group (Group Ⅰ), model group (Group Ⅱ), atorvastatin group (Group Ⅲ) and FTZ group (Group Ⅳ), with 7 rabbits in each group. Vascular stenosis was analyzed with Digital Subtraction Angiography. Level of adiponectin (APN), and inflammatory factor including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) as well as monocyte chemoattractant protein-1 (MCP-1) was measured by Enzyme Linked Immunosorbent Assay; and injured iliac artery was collected for Hematoxylin-eosin staining and Western Blotting detection of expression of peroxisome proliferator-activated receptor-alpha (PPAR-α), adenosine 5'-monophosphate -activated protein kinase (AMPK) and phosphorylated adenosine 5'-monophosphate -activated protein kinase (p-AMPK). Besides, we evaluated FTZ's safety for the first time.

KEY RESULTS

Percutaneous iliac artery transluminal balloon angioplasty and high-fat diet result in inflammatory response and restenosis. Compared with Group Ⅱ, iliac artery restenosis was significantly ameliorated in Group Ⅳ (P < 0.05). Treated with FTZ, serum lipids were significantly decreased (P < 0.01), while the level of APN was elevated significantly (P < 0.01). Western blotting detection of the injured iliac artery showed that the expressions of PPAR-α, AMPK and p-AMPK were significantly increased in Group Ⅳ (P < 0.01) than that in Group Ⅱ. Besides, before and after taking drugs, liver and kidney function indicators, creatine kinase, as well as measurement of echocardiography were of no statistical difference in four groups(P > 0.05).

CONCLUSIONS AND IMPLICATIONS

FTZ could effectively reduce serum lipids and ameliorate rabbit's iliac artery restenosis after angioplasty, and its mechanism may be related to activation of APN signaling pathway.

Potential Involvement of Adiponectin Signaling in Regulating Physical Exercise-Elicited Hippocampal Neurogenesis and Dendritic Morphology in Stressed Mice

Adiponectin, a cytokine secreted by mature adipocytes, proves to be neuroprotective. We have previously reported that running triggers adiponectin up-regulation which subsequently promotes generation of hippocampal neurons and thereby alleviates depression-like behaviors in non-stressed mice. However, under the stressing condition, whether adiponectin could still exert antidepressant-like effects following exercise remained unexplored. In this study, by means of repeated corticosterone injections to mimic stress insult and voluntary wheel running as physical exercise intervention, we examined whether exercise-elicited antidepressive effects might involve adiponectin's regulation on hippocampal neurogenesis and dendritic plasticity in stressed mice. Here we show that repeated injections of corticosterone inhibited hippocampal neurogenesis and impaired dendritic morphology of neurons in the dentate gyrus of both wild-type and adiponectin-knockout mice comparably, which subsequently evoked depression-like behaviors. Voluntary wheel running attenuated corticosterone-suppressed neurogenesis and enhanced dendritic plasticity in the hippocampus, ultimately reducing depression-like behaviors in wild-type, but not adiponectin-knockout mice. We further demonstrate that such proneurogenic effects were potentially achieved through activation of the AMP-dependent kinase (AMPK) pathway. Our study provides the first evidence that adiponectin signaling is essential for physical exercise-triggered effects on stress-elicited depression by retaining the normal proliferation of neural progenitors and dendritic morphology of neurons in the hippocampal dentate gyrus, which may depend on activation of the AMPK pathway.

Evaluation of Adipokines Concentration in Iraqi Patients with Major and Minor Beta Thalassemia

Background

Beta thalassemia (β-thalassemia) is a type of inherited blood disorder characterized by the impaired production of beta globin chains. β-Thalassemia can be categorized into three subtypes according to symptom severity: β-thalassemia minor, β-thalassemia intermedia, and β-thalassemia major. Adipose tissue functions as an endocrine gland by synthesizing and secreting an array of bioactive peptides including leptin, adiponectin, and resistin.

Methods

We recruited 30 participants who were transfusion dependent β-thalassemia patients (major) and 30 participants who were non-transfusion dependent β-thalassemia patients (minor). The control group consisted of 20 healthy individuals. Analysis of the demographic profile, hematological profile, biochemical parameters, and serum adipokine concentrations (leptin, adiponectin and resistin) were performed for all participants.

Results

Our results showed that leptin serum levels were significantly lower in the β-thalassemia major group compared with the β-thalassemia minor group or healthy individuals, while serum levels of adiponectin were significantly higher in β-thalassemic patients compared with healthy controls. Serum levels of resistin were significantly higher in β-thalassemic patients compared with the healthy control group. A significant negative correlation was noted between adiponectin and BMI in β-thalassemic patients, whereas leptin was observed to have a significant positive correlation with BMI in the control group. Leptin was observed to have a significant negative correlation with adiponectin and ferritin in the β-thalassemia major group.

Conclusion

The changes we observed in adipokine levels may play a role in the development of the complications related to β-Thalassemia and disease severity.

Therapeutic effects of AdipoRon on liver inflammation and fibrosis induced by CCl4 in mice

OBJECTIVE

The present work aimed to investigate the effects of AdipoRon against acute hepatitis and liver fibrosis induced by carbon tetrachloride (CCl₄) in mice.

METHODS

C57BL/6 mice were randomly divided into five groups: control, model, AdipoRon groups (three different dosages), CCl₄ was administered to induce acute hepatitis or liver fibrosis except for control group. The liver function, inflammatory and fibrotic profiles were evaluated by histology, immunohistochemistry and expression analysis, respectively.

RESULTS

AdipoRon pretreatment effectively attenuated oxidative stress and hepatocellular damage in acute CCl₄ intoxication, demonstrated by marked reduction in peroxidation indexes [hepatic malonaldehyde (MDA), total nitric oxide synthase (tNOS), inducible nitric oxide synthase (iNOS)] and serum transaminases [alanine aminotransferase (ALT), aspartate transaminase (AST)]. Moreover, AdipoRon attenuated the severity of fibrosis induced by sustaining CCl₄ challenge, with the alleviation of fibrous deposit and architecture distortion. The levels of canonical fibrosis markers (aminotransferases, hydroxyproline, hyaluronic acid, laminin) were also dose-dependently modulated by AdipoRon. Immunochemistry and expression analysis showed AdipoRon restrained the proinflammatory and profibrotic cytokines (TNF-α, TGF-β1, α-SMA, COL1A1), which somehow, ascribed the anti-fibrotic action to inhibiting hepatic stellate cells (HSCs) activation and quenching specific inflammation-fibrogenesis pathways.

CONCLUSIONS

AdipoRon demonstrates a remedial capacity against hepatitis and fibrosis induced by CCl₄, potentially by inflammation restraint and HSC deactivation, which might pave the way for its therapeutical application in hepatic fibrosis.

New Insights into Adipokines as Potential Biomarkers for Type-2 Diabetes Mellitus

A large number of studies have been focused on investigating serum biomarkers associated with risk or diagnosis of type-2 diabetes mellitus. In the last decade, promising studies have shown that circulating levels of adipokines could be used as a relevant biomarker for diabetes mellitus progression as well as therapeutic future targets. Here, we discuss the possible use of recently described adipokines, including apelin, omentin-1, resistin, FGF-21, neuregulin-4 and visfatin, as early biomarkers for diabetes. In addition, we also include recent findings of other well known adipokines such as leptin and adiponectin. In conclusion, further studies are needed to clarify the pathophysiological significance and clinical value of these biological factors as potential biomarkers in type-2 diabetes and related dysfunctions.

Effects of growth hormone therapy on metabolic parameters, adipokine and endothelial dysfunction in prepuberal children

AIM

To determine whether non-obese prepubertal children with growth hormone deficiency (GHD) present changes in lipid metabolism, and adipokines, and to assess the short-term effects of growth hormone (GH) treatment on these parameters.

METHODS

Prospective observational follow-up and case-control (36 GHD children and 38 healthy children) study lasted for six months. Means of values from groups were compared, control group versus GHD baseline group, and GHD baseline group versus GHD after six months of GH replacement therapy. Lipid profile, glucose, insulin, homeostatic model assessment - insulin resistance (HOMA-IR), leptin, adiponectin and soluble intercellular adhesion molecule-1 (sICAM-1) were all analysed.

RESULTS

Growth hormone deficiency children show higher baseline levels of total cholesterol, LDL cholesterol, triglycerides, Apo B and sICAM-1, but lower levels of free fatty acids, insulin and HOMA-IR. After six months of treatment, cholesterol, LDL cholesterol, Apo B, T cholesterol/HDL cholesterol, insulin, HOMA-IR and leptin levels decreased. The changes in insulin and HOMA-IR levels correlated inversely with the changes in HDL cholesterol and Apo A1 levels. A correlation was also observed between the changes in adiponectin levels and the changes in HDL cholesterol and Apo A1 levels. Variations in leptin levels were correlated with changes in triglycerides.

CONCLUSION

Prepubertal non-obese GHD children present altered lipid profiles and adipokine levels. Replacement therapy with GH improves these variables.

Plasma concentration and expression of adipokines in epicardial and subcutaneous adipose tissue are associated with impaired left ventricular filling pattern

Background

Adipokines in serum derive mainly from subcutaneous and visceral adipose tissues. Epicardial adipose tissue (EAT), being a relatively small but unique fat depot, probably does not make an important contribution to systemic concentrations of adipokines. However, proximity of EAT to cardiac muscle and coronary arteries allows cells and proteins to penetrate between tissues. It is hypothesized that overexpression of proinflammatory cytokines in EAT plays an important role in pathophysiology of the heart. The aim of the study was to analyze the relationship between echocardiographic heart parameters and adipokines in plasma, epicardial, and subcutaneous fat in patients with obesity and type 2 diabetes mellitus (T2DM). Additionally, we evaluate proinflammatory properties of EAT by comparing that depot with subcutaneous adipose tissue.

Methods

The study included 55 male individuals diagnosed with coronary artery disease (CAD) who underwent planned coronary artery bypass graft. Plasma concentrations of leptin, adiponectin, resistin, visfatin, apelin, IL-6, and TNF-α, as well as their mRNA and protein expressions in EAT and subcutaneous adipose tissue (SAT) were determined.

Results

Obesity and diabetes were associated with increased leptin and decreased adiponectin plasma levels, higher protein expression of leptin and IL-6 in SAT, and higher visfatin protein expression in EAT. Impaired left ventricular (LV) diastolic function was associated with increased plasma concentrations of leptin, resistin, IL-6, and adiponectin, as well as with increased expressions of resistin, apelin, and adiponectin in SAT, and leptin in EAT.

Conclusions

Obesity and T2DM in individuals with CAD have a limited effect on adipokines. Expression of adipokines in EAT and SAT is linked to certain heart parameters, however diastolic dysfunction of the LV is strongly associated with circulating adipokines.

Assessing the variability and predictability of adipokines (adiponectin, leptin, resistin and their ratios) in non-obese and obese women with anovulatory polycystic ovary syndrome

Objectives

To assess the variability and predictability of adiponectin, leptin, resistin and their ratios in non-obese and obese women with anovulatory polycystic ovary syndrome (aPCOS).

Results

A total of 52 ovulatory controls (mean age = 31.63 ± 4.88 years, BMI = 25.33 ± 2.68 kg/m²); 54 non-obese (mean age = 32.11 ± 4.25 years, BMI = 25.72 ± 2.95 kg/m²) and 50 obese women with aPCOS (mean age = 33.64 ± 4.14 years, BMI = 39.19 ± 2.99 kg/m²) were recruited. The aPCOS group had lower adiponectin [13.0 (10.49–16.59) vs 18.42 (15.72–19.92) µg/ml, p < 0.0001], adiponectin: leptin ratio (A:L) [0.60 (0.35–0.88) vs 1.19 (0.92–1.37), p < 0.0001], and adiponectin: resistin ratio (A:R) [0.30 (0.21–0.43) vs 0.42 (0.32–0.62), p < 0.0001] but a higher leptin [20.02 (14.54–26.80) vs 16.17 (14.51–18.36) ng/ml, p < 0.0001] and leptin: resistin ratio (L:R) [0.53 (0.37–0.82) vs 0.40 (0.27–0.48), p < 0.0001] compared to the controls. The obese aPCOS group had lower adiponectin [11.04 (5.66–13.25) vs 14.18 (11.04–18.02), p < 0.0001 and 18.42 (15.72–19.92) µg/ml, p < 0.0001], A:L [0.36 (0.27–0.44) vs 0.78 (0.61–1.16), p < 0.0001 and 1.19 (0.92–1.37), p < 0.0001], and A:R [0.24 (0.17–0.38) vs 0.40 (0.23–0.58), p < 0.0001 and 0.42 (0.32–0.62), p < 0.0001] but a higher leptin [26.80 (14.28–32.09) vs 17.95 (14.86–21.26), p < 0.05 and 16.17 (14.51–18.36) ng/ml, p < 0.0001] and L:R [0.63 (0.46–1.03) vs 0.41 (0.30–0.61), p < 0.0001 and 0.40 (0.27–0.48), p < 0.0001] compared to the non-obese aPCOS and control group, respectively. A:L showed the best discriminatory power in predicting aPCOS (AUC = 0.83), followed by adiponectin alone (AUC = 0.79), L:R and leptin alone (both AUC = 0.69). Resistin alone had the poorest discriminatory power (AUC = 0.48).

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4546-z) contains supplementary material, which is available to authorized users.

Adiponectin and the risk of new-onset atrial fibrillation: a meta-analysis of prospective cohort studies

Background: Adiponectin has been suggested as a marker of many cardiovascular diseases. However, the association between serum adiponectin and incidence of atrial fibrillation (AF) in general population remains unclear. A meta-analysis was performed to systematically evaluate the potential influence of serum adiponectin at baseline on the incidence of AF during follow-up in general population.

Methods: Prospective cohort studies were identified via electronic search of PubMed and Embase databases. A randomized effect model was applied to combine the results. Predefined subgroup analyses were performed to evaluate the influence of study characteristics on the association between baseline adiponectin and risk of new-onset AF.

Results: Six cohort studies with 18558 community-derived participants were included, and 3165 AF cases were developed with a mean follow-up duration of up to 22 years. Meta-analysis showed that higher baseline circulating adiponectin was significantly associated with higher risk of new-onset AF during follow-up (hazard ratio [HR]: 1.17, 95% confidence interval [CI]: 1.08–1.27, P<0.001, I² = 52%). Subgroup analyses showed that the association between adiponectin and new-onset AF was significant in studies with mean follow-up duration over 10 years (five cohorts, HR = 1.22, P<0.001), but not in that with a follow-up duration < 10 years (one cohort, HR = 0.95, P=0.51; P for subgroup difference = 0.002).

Conclusions: Higher circulating adiponectin at baseline may be an independent risk factor for the development of new-onset AF during follow-up, particularly in cohort studies with longer follow-up durations.

Cynometra cauliflora Linn. Attenuates metabolic abnormalities in high-fat diet-induced obese mice

ETHNOPHARMACOLOGICAL RELEVANCE

Cynometra cauliflora Linn. belongs to the Fabaceae family and is known locally in Malaysia as nam-nam. Traditionally, a decoction of the C. cauliflora leaves is used for treating hyperlipidemia and diabetes.

AIM OF THE STUDY

This study aims to investigate the anti-obesity and lipid lowering effects of ethanolic extract of C. cauliflora leaves and its major compound (vitexin) in C57BL/6 obese mice induced by high-fat diet (HFD), as well as to further identify the molecular mechanism underlying this action.

METHODS AND MATERIAL

Male C57BL/6 mice were fed with HFD (60% fat) for 16 weeks to become obese. The treatment started during the last 8 weeks of HFD feeding and the obese mice were treated with C. cauliflora leaf extract at 200 and 400 mg/kg/day, orlistat (10 mg/kg) and vitexin (10 mg/kg).

RESULTS

The oral administration of C. cauliflora (400 and 200 mg/kg) and vitexin significantly reduced body weight, adipose tissue and liver weight and lipid accumulation in the liver compared to control HFD group. Both doses of C. cauliflora also significantly (P ≤ 0.05) decreased serum triglyceride, LDL, lipase, IL-6, peptide YY, resistin levels, hyperglycemia, hyperinsulinemia, and hyperleptinemia compared to the control HFD group. Moreover, C. cauliflora significantly up-regulated the expression of adiponectin, Glut4, Mtor, IRS-1 and InsR genes, and significantly decreased the expression of Lepr in white adipose tissue. Furthermore, C. cauliflora significantly up-regulated the expression of hypothalamus Glut4, Mtor and NF-kB genes. GC-MS analysis of C. cauliflora leaves detected the presence of phytol, vitamin E and β-sitosterol. Besides, the phytochemical evaluation of C. cauliflora leaves showed the presence of flavonoid, saponin and phenolic compounds.

CONCLUSION

This study shows interesting outcomes of C. cauliflora against HFD-induced obesity and associated metabolic abnormalities. Therefore, the C. cauliflora extract could be a potentially effective agent for obesity management and its related metabolic disorders such as insulin resistance and hyperlipidemia.

Effect of pravastatin treatment on circulating adiponectin: a meta-analysis of randomized controlled trials

Objective

Pravastatin has been suggested to increase circulating adiponectin in humans. However, results of randomized controlled trials (RCTs) are inconsistent. We aimed to systematically evaluate the influence of pravastatin on circulating adiponectin in humans by performing a meta-analysis of RCTs.

Materials and methods

Studies were identified via systematic searching of PubMed, Embase, and Cochrane’s Library databases. A random effect model was used to pool the results. Meta-regression and subgroup analyses were applied to explore the source of heterogeneity.

Results

Eight RCTs with nine comparisons of 595 participants were included. Pravastatin treatment was associated with a significant increased level of circulating adiponectin as compared with controls (weighted mean difference [WMD] =0.63 µg/mL; 95% CI, 0.17–1.09 µg/mL; P=0.007) with moderate heterogeneity (I2=28%). These results were confirmed by meta-analysis of double-blinded placebo-controlled RCTs (WMD =0.82 µg/mL; P=0.01). Meta-regression analyses indicated that proportions of males in each study were positively correlated with the effect of pravastatin on adiponectin (coefficient: 0.015, P=0.03). Subgroup analyses confirmed that pravastatin significantly increased adiponectin in studies of males (WMD =1.41 µg/mL; P=0.008), but not in those of females (WMD =−0.04 µg/mL; P=0.94).

Conclusion

Pravastatin treatment is associated with increased circulating adiponectin. Gender difference may exist regarding the effect of pravastatin treatment on adiponectin.

Constant-Moderate and High-Intensity Interval Training Have Differential Benefits on Insulin Sensitive Tissues in High-Fat Fed Mice

In a mouse model of diet-induced obesity, this study determined if two exercise prescriptions with equivalent time and distance covered, [constant-moderate endurance (END) and high intensity interval training (HIIT)], exert differential metabolic benefits on insulin sensitive tissues. Male 10 week old C57BL/6 mice were fed a high fat diet (HFD; 45% kcal fat) ad libitum for 10 weeks and for a further 10 weeks they underwent END or HIIT training (3 × 40 min sessions/wk). Untrained HFD and chow-fed mice acted as controls. At 30 weeks of age, mice were sacrificed and quadriceps muscle, subcutaneous adipose tissue (SAT) and liver were excised. Neither END nor HIIT altered body weight or composition in HFD mice. In quadriceps, HFD decreased high-molecular weight adiponectin protein, which was normalized by END and HIIT. In contrast, HIIT but not END reversed the HFD-driven decrease in the adiponectin receptor 1 (AdipoR1). In SAT, both programs tended to decrease collagen VI protein (p = 0.07–0.08) in HFD, whereas only HIIT induced an increase in the mRNA (3-fold vs. HFD untrained) and protein (2-fold vs. HFD untrained) of UCP1. In liver, only END reversed collagen I accumulation seen in HFD untrained mice. Our results suggest that HIIT may promote better systemic metabolic changes, compared to END, which may be the result of the normalization of muscle AdipoR1 and increased UCP1 seen in SAT. However, END was more effective in normalizing liver changes, suggesting differential metabolic effects of END and HIIT in different tissues during obesity.

Adiponectin confers neuroprotection against cerebral ischemia-reperfusion injury through activating the cAMP/PKA-CREB-BDNF signaling

Ischemic stroke is a severe cerebrovascular disease. Although great progress has been made, the consequent ischemia-reperfusion (I/R) injury is inevitable and affects the therapeutic effect. Adiponectin (APN) is a fat-derived plasma protein that has beneficial actions on cardiovascular disorders. The present study aims to investigate the effect of APN on I/R injury and the potential underlying mechanisms. In step 1, APN were administered for three times (once every 8 h) 24 h before middle cerebral artery occlusion (MCAO). The results indicated that APN treatment reduced infarct volume, neurological deficits and brain water content after I/R injury. Meanwhile, APN was proved to increase the expression of cAMP, PKA, CREB, and BDNF. In step 2, mice were randomly assigned into the Vehicle + I/R, APN + I/R, PKA activator + I/R, PKA inhibitor + APN + I/R groups. PKA activator, PKA inhibitor, as well as APN were administered for three times before MCAO. The results indicated that PKA inhibitor downregulated the expressions of cAMP, PKA, CREB, and BDNF which subsequently weakened the protective effects of APN on cerebral I/R injury. In conclusion, our findings further suggest that APN exerts protective effect against cerebral I/R injury might through the cAMP/PKA-CREB-BDNF signaling pathway. APN is a novel candidate in the treatment of I/R diseases in the future.

Activating Adiponectin Signaling with Exogenous AdipoRon Reduces Myelin Lipid Accumulation and Suppresses Macrophage Recruitment after Spinal Cord Injury

Myelin-laden macrophages (mye-MΦ), resulting primarily from internalization of myelin debris by infiltrating bone marrow-derived macrophages in spinal cord injury (SCI), trigger inflammatory responses that largely contribute to secondary injury. Adiponectin, which is secreted from adipose tissue, is an important hormone that modulates macrophage inflammation. In the present study, we examined the role of adiponectin on macrophage-mediated neuroinflammation after SCI. We found that in vitro activation of adiponectin receptors (AdipoRs) by their agonist AdipoRon suppressed myelin lipid accumulation in mye-MΦ through APPL1/PPARγ/LXRα/ABCA1-mediated lipid efflux, subsequently inhibiting inflammation and restoring normal function to mye-MΦ. In vivo data further confirmed that intravenous administration of AdipoRon after SCI dampened recruitment of macrophages and reduced myelin lipid accumulation. Accordingly, AdipoRon treatment ameliorated post-SCI tissue damage and astrogliosis, resulting in improved motor function. Although there was no significant pathological exacerbation in adiponectin-null mice subjected to SCI, our work reveals a functional link between adiponectin and hematogenous macrophages in the context of SCI, suggesting that activation of adiponectin signaling is a promising therapeutic approach to mitigate mye-MΦ-mediated neuroinflammation in neurological disorders involving demyelination.

Grape Juice Consumption with or without High Fat Diet during Pregnancy Reduced the Weight Gain and Improved Lipid Profile and Oxidative Stress Levels in Liver and Serum from Wistar Rats

The aim of this study was to evaluate the effects of high fat diet with or without grape juice during the pregnancy on gestational weight gain, biochemical parameters, and oxidative stress in plasma and liver from Wistar rats. Forty-nine rats were divided into four groups: control diet group (CD), high fat diet (HFD), grape juice and control diet (PGJCD), and grape juice and high fat diet (PGJHFD). During the treatment the weight gain of the rats was tracked. They had free access to their respective diets during 42 days of treatment. After offspring weaning, the mother rats were euthanized and blood and liver were collected. The high fat diet increased the total cholesterol and triglycerides serum levels as well as carbonyl levels in the liver, however this diet reduced the high-density lipoprotein (HDL) and urea levels in serum. Grape juice consumption reduced gestational body weight gain. In liver, the juice consumption increased sulfhydryl levels and reduced the superoxide dismutase (SOD) activity and TBARS level, in serum the consumption reduced aspartate aminotransferase (AST) and TBARS. We can conclude that the consumption of a diet rich in fat can promotes harmful effects on health during pregnancy, however the consumption of grape juice seems to be an important alternative to prevent oxidative damages and to promote the improvement of health.

Adiponectin signaling and its role in bone metabolism

Adiponectin, the most prevalent adipo-cytokine in plasma plays critical metabolic and anti-inflammatory roles is fast emerging as an important molecular target for the treatment of metabolic disorders. Adiponectin action is critical in multiple organs including cardio-vascular system, muscle, liver, adipose tissue, brain and bone. Adiponectin signaling in bone has been a topic of active investigation lately. Human association studies and multiple mice models of gene deletion/modification failed to define a clear cause and effect of adiponectin signaling in bone. The most plausible reason could be the multimeric forms of adiponectin that display differential binding to receptors (adipoR1 and adipoR2) with cell-specific receptor variants in bone. Discovery of small molecule agonist of adipoR1 suggested a salutary role of this receptor in bone metabolism. The downstream signaling of adipoR1 in osteoblasts involves stimulation of oxidative phosphorylation leading to increased differentiation via the likely suppression of wnt inhibitor, sclerostin. On the other hand, the inflammation modulatory effect of adiponectin signaling suppresses the RANKL (receptor activator of nuclear factor κ-B ligand) - to - OPG (osteprotegerin) ratio in osteoblasts leading to the suppression of osteoclastogenic response. This review will discuss the adiponectin signaling and its role in skeletal homeostasis and critically assess whether adipoR1 could be a therapeutic target for the treatment of metabolic bone diseases.

Contribution of adiponectin polymorphisms to the risk of coronary artery disease in a North-African Tunisian population

BACKGROUND

Adiponectin, an adipocyte-derived protein, is known to play a key role in the processes leading to atherosclerosis and coronary artery disease (CAD) through its anti-atherogenic, anti-inflammatory, antioxidative, and anti-apoptotic properties. In the current study, we have studied the association of two single nucleotide polymorphisms (SNPs) +45 T>G (rs2241766) and +276 G>T (rs1501299) of the adiponectin gene with coronary artery disease (CAD) on an Arab/North-African population from Tunisia.

METHODS

Subjects comprised 277 patients with angiographically demonstrated CAD and 269 age- and gender-matched control subjects. The adiponectin genotypes were performed by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). The contribution of adiponectin variants to CAD was analyzed by haplotype and regression analysis.

RESULTS

Adiponectin +45T>G and +276G>T genotypic and allelic distributions did not show a significant difference between cases and controls. Similarly, no association with CAD was observed for the haplotype analysis. Assuming dominant model of transmission for both polymorphisms and after adjustment of a number of traditional risk factors for CAD, logistic regression analysis showed an association of SNP +45 T>G with increased risk of developing CAD [adjusted OR (95% CI) = 2.59 (1.17-5.70); P = .01]. However, SNP + 276 G>T is associated with decreased risk of developing CAD [adjusted OR (95% CI) = 0.47 (0.22-0.97); P = .04].

CONCLUSION

There is no allelic or genotypic association of +45 T>G and +276 G>T of the adiponectin gene with CAD in the Tunisian population.

Distribution of Adiponectin Receptors 1 and 2 in the Rat Olfactory Bulb and the Effect of Adiponectin Injection on Insulin Receptor Expression

BACKGROUND

Adiponectin (APN) is an adipocyte-derived hormone that has peripheral beneficial effects. Although its receptors AdipoR1 and AdipoR2 are expressed in the brain, their function in neurons is poorly understood. The aims of this work were to describe the distribution of APN receptors in the olfactory bulb (OB) as well as the possible effects of APN injection on the insulin receptor (InsR) content and Akt kinase.

METHOD

We performed the double immunofluorescence technique to describe the distribution of AdipoRs and the cellular type they were expressing. mRNA transcript and protein content were assessed by RT-PCR and Western blot, respectively. APN injection was performed to analyze its possible effect on the insulin pathway.

RESULTS

We found that AdipoRs were localized in all cell layers and in both neurons and astrocytes. We observed the presence of mRNA transcripts and immunoblot analysis confirmed the protein on the intact OB; APN injection in the OB resulted in a slight decrease of the total InsR and Akt phosphorylation and a reduction of phopho-InsR content.

CONCLUSIONS

These data demonstrated that AdipoRs are expressed in OB regions, and APN injection could act as an insulin pathway modulator in the OB and thus possibly contribute to olfaction physiology.

Analysis of the correlation between adiponectin gene polymorphism and metabolic syndrome incidence and its relationship with the degree of atherosclerosis in patients

The aim of the present study was to determine the correlation between adiponectin (APN) gene polymorphism, metabolic syndrome incidence, and degree of atherosclerosis in patients with this disease. The study was conducted on 369 unrelated patients, diagnosed with metabolic abnormalities. The patients were divided into the metabolic syndrome group (MS group, n=182), the metabolic abnormality group (n=187) and the control group with metabolic normality (n=134), as per the degree of metabolic abnormality. The gene polymorphism of rs121917815 site of APN gene was detected by TaqMAN probe technique, and the OR values of different genotypes and alleles were calculated. The APN protein, C-reactive protein (CRP), IL-1 and high-density lipoprotein (HDL) 2a and 2b expression level changes were detected by immunoblotting. The atherosclerosis index (AI) of each allele in patients with MS was calculated. Compared with the control group, the expression levels of APN protein in the metabolic abnormality and MS groups were significantly decreased. However, there was no distinct difference in the comparison of gene polymorphism between the control and metabolic abnormality groups. The CC genotype frequency and C allele frequency of rs121917815 polymorphic site in the MS group were significantly increased, compared with the control group. The TT genotype frequency and T allele frequency were significantly decreased and the OR values of the CC genotype and C allele were increased. The results of immunoblotting showed that there was no obvious change of CRP, IL-1, HDL-2a and HDL-2b in the three groups, and there was no statistically significant difference in the comparison of AI between the MS and control groups as well as the metabolic abnormality group. The APN gene polymorphic site rs121917815 is associated with MS. The occurrence of CC genotype and C allele increased the incidence of MS, but it did not increase the degree of atherosclerosis in MS patients.

Adiponectin and its receptors are involved in hypertensive vascular injury

Adipocyte-derived adiponectin (APN) is involved in the protection against cardiovascular disease, but the endogenous APN and its receptor expression in the perivascular adipocytes and their role in hypertensive vascular injury remain unclear. The present study aimed to detect endogenous APN and its receptor expression and their protective effects against hypertensive vascular injury. APN was mainly expressed in the perivascular adipocytes, while its receptors AdipoR1 and AdipoR2 were ubiquitously expressed in the blood vessels. Angiotensin II (Ang II)-induced hypertension resulted in a significant decrease of APN and AdipoR1 and AdipoR2 in the perivascular adipocytes and vascular cells. The migration assay used demonstrated that APN attenuated Ang II-induced vascular smooth muscle cells migration and p38 phosphorylation Furthermore, the in vivo study demonstrated that APN receptor agonist AdipoRon attenuated Ang II-induced hypertensive vascular hypertrophy and fibrosis. Taken together, the present study indicated that perivascular adipocytes-derived APN attenuated hypertensive vascular injury possibly via its receptor-mediated inhibition of p38 signaling pathway.

Adiponectin improves the osteointegration of titanium implant under diabetic conditions by reversing mitochondrial dysfunction via the AMPK pathway in vivo and in vitro

Diabetes-induced reactive oxygen species (ROS) overproduction would result in compromised osteointegration of titanium implant (TI) and high rate of implant failure, yet the underlying mechanisms remain elusive. Adiponectin (APN) is a fat-derived adipocytokine with strong antioxidant, mitochondrial-protective and anti-diabetic efficacies. We hypothesized that mitochondrial dysfunction under diabetes may account for the oxidative stress in osteoblasts and titanium-bone interface (TBI) instability, which could be ameliorated by APN. To test this hypothesis, we incubated primary rat osteoblasts on TI and tested the cellular behaviors when subjected to normal milieu (NM), diabetic milieu (DM), DM+APN, DM+AICAR (AMPK activator) and DM+APN+Compound C (AMPK inhibitor). In vivo, APN or APN+Compound C were administered to diabetic db/db mice with TI implanted in their femurs. Results showed that diabetes induced structural damage, dysfunction and content decrease of mitochondria in osteoblasts, which led to ROS overproduction, dysfunction and apoptosis of osteoblasts accompanied by the inhibition of AMPK signaling. APN alleviated the mitochondrial damage by activating AMPK, thus reversing osteoblast impairment and improving the osteointegration of TI evidenced by Micro-CT and histological analysis. Furthermore, AICAR showed beneficial effects similar to APN treatment, while the protective effects of APN were abolished when AMPK activation was blocked by Compound C. This study clarifies mitochondrial dysfunction as a crucial mechanism in the impaired bone healing and implant loosening in diabetes, and provides APN as a novel promising active component for biomaterial-engineering to improve clinical performance of TI in diabetic patients.

STATEMENT OF SIGNIFICANCE

The loosening rate of titanium implants in diabetic patients is high. The underlying mechanisms remain elusive and, with the rapid increase of diabetic morbility, efficacious strategies to mitigate this problem have become increasingly important. Our study showed that the mitochondrial impairment and the consequent oxidative stress in osteoblasts at the titanium-bone interface (TBI) play a critical role in the diabetes-induced poor bone repair and implant destabilization, which could become therapeutic targets. Furthermore, adiponectin, a cytokine, promotes the bio-functional recovery of osteoblasts and bone regeneration at the TBI in diabetes. This provides APN as a novel bioactive component used in material-engineering to promote the osteointegration of implants, which could reduce implant failure, especially for diabetic patients.

Effects of vitamin D and resveratrol on metabolic associated markers in liver and adipose tissue from SAMP8 mice

SAMP8 mice exhibit multiple metabolic characteristics associated with age, and it is a suitable candidate for researching aging associated metabolic dysfunction.

OBJECTIVES

We aimed to 1) explore how key metabolic markers will be altered in both liver and adipose tissue with aging in SAMP8 mice; and 2) how the combination of vitamin D (VD) with resveratrol (RSV) will affect aging associated metabolic impairment in liver and adipose tissue from SAMP8 mice.

METHODS

SAMP8 mice and their control SAMR1 mice were divided into 5 groups, i.e. SAMR1, SAMP8, SAMP8 mice supplemented with VD, RSV and VD combined with RSV group, respectively. At the end of the intervention, glucose and insulin tolerance, p-AMP-activated protein kinase (AMPK) and amyloid precursor protein (APP), and endoplasmic reticulum (ER) stress markers in liver and adipose tissue, adiponectin secretion, p-NF-κBp65 and TNF-α protein expression in adipose tissue were determined.

RESULTS

Compared to SAMR1 control, SAMP8 mice demonstrate impaired glucose tolerance and reduction in circulating adiponectin level; in the liver, SAMP8 mice have reduction in p-Aktser473, elevation in PTP1B and APP, p-eIF2α, GRP78 and p-JNK protein expression. In epididymal (EPI) fat, SAMP8 mice also have elevated p-Aktser473 and PTP1B compared to SAMR1 mice. In both epididymal (EPI) and subcutaneous (SC) fat, there were elevated ER stress markers, reduced p-AMPK and elevated APP, as well as elevated p-NF-κBp65 and TNF-α protein expression from SAMP8 compared to SAMR1 mice. In liver, the combined intervention significantly restored p-Aktser473, p-eIF2α and p-JNK protein expression. In both EPI and SC fat, the combined intervention is effective for reducing p-NF-κB p65 and TNF-α in both fat depot, while only partially reduced ER stress markers in SC fat. As for adiponectin, their combination is unable to reverse reduction in adiponectin level. Adiponectin secretion in SC fat from VD, RSV and VDRSV group were also significantly reduced compared to SAMR1.

CONCLUSION

The combined intervention might exert greater beneficial effects for reversing aging associated metabolic dysfunction in liver and adipose tissue from SAMP8 mice.

High Molecular Weight Adiponectin Levels are Neither Influenced by Adiponectin Polymorphisms Nor Associated with Insulin Resistance in Mixed-ancestry Hyperglycemic Subjects from South Africa

Background

High molecular weight (HMW) adiponectin has antiatherogenic, antiinflammatory and antidiabetic properties and these effects have been linked to its effect on high density lipoprotein cholesterol (HDL-c). Single nucleotide polymorphisms (SNPs) in the adiponectin gene influence adiponectin levels. We examined the relationship between HMW-adiponectin levels and cardiometabolic traits in normo- and hyperglycemic mixed ancestry South Africans and correlated these levels to two common polymorphisms.

Methods

HMW-adiponectin was determined in 101 subjects from the Cape Town Bellville South community-based study on a mixed ancestry population. Comparisons were made between individuals with normo- and hyperglycemia. Two common SNPs, ADIPOQ SNPs rs17300539 and rs266729, known to affect adiponectin levels were also tested for. Levels of HMW-adiponectin were then correlated with cardiometabolic traits in all groups.

Results

Levels of HMW-adiponectin were not significantly different in the normo- and hyperglycemic groups (median 11.6 vs. 10.5 μg/mL, p=0.3060) and in men and women (8.44 vs. 11.34 μg/mL, p=0.67). ADIPOQ SNPs rs17300539 and rs266729 did not influence levels of HMW-adiponectin. Robust correlation analyses revealed a significant positive correlation between HMW-adiponectin and HDL-c (r=0.45; 95%CI: 0.27–0.59), similarly in normo- and hyperglycemic participants (p > 0.99). This association was substantially attenuated in robust linear regressions adjusted for age, gender and adiposity.

Conclusions

Adiponectin levels in this population were not determined by the commonest SNPs of the adiponectin gene, were unaffected by glycemic status; but were significantly correlated with HDL-c levels. Previous studies have attributed some of the beneficial effects of adiponectin to its effect on HDL-c.

Hepatoprotective effects of AdipoRon against d-galactosamine-induced liver injury in mice

Adiponectin is an antidiabetic and antiatherogenic adipokine, which plays distinct roles in the balance of energy homoeostasis. As an insulin sensitizing hormone, adiponectin exerts multiple biological effects by the specific receptors (AdipoR1 and AdipoR2), through activation of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor (PPAR)α pathways. AdipoRon, an orally active synthetic small-molecule AdipoR agonist, shows very similar effects to adiponectin in vitro and in vivo, which could be a promising therapeutic approach for obesity-related disorders. In view of the regulatory effects of adiponectin or AdipoRon on inflammatory response and energy metabolism, they might be endowed a curative potential for tissue damage. Hence, its effects and possible mechanism were investigated. In vitro studies on hepatocytes (L02) and macrophages (RAW264.7) suggested a protective and anti-inflammatory potential of AdipoRon. The effects were verified in acute hepatic injury mice induced by d-galactosamine (D-GalN): hepatic lesions were restored by AdipoRon or bicyclol (positive reference drug) pretreatment, which were characterized by a significant increase in serological and hepatic biomarkers (AST, ALT, MDA and NOSs). Besides, AdipoRon attenuated the inflammation in the liver, characterized by the dwindling proinflammatory macrophage infiltration, as well as the shrinkage of tumor necrosis factor-α (TNF-α), transforming growth factor beta 1 (TGF-β1), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6); meanwhile conversely promoted AMPK activation by phosphorylation. Combined with liver histopathology, these results demonstrated the hepatoprotective effects of AdipoRon against D-GalN-induced damage, which might be ascribed to the attenuation of inflammation, inhibition of free radical reactions, as well as enhancement of liver energy metabolism.