Serum adiponectin level as an independent predictor of mortality in patients with congestive heart failure

From Beats to Metabolism: the Heart at the Core of Interorgan Metabolic Cross Talk

The heart, once considered a mere blood pump, is now recognized as a multifunctional metabolic and endocrine organ. Its function is tightly regulated by various metabolic processes, at the same time it serves as an endocrine organ, secreting bioactive molecules that impact systemic metabolism. In recent years, research has shed light on the intricate interplay between the heart and other metabolic organs, such as adipose tissue, liver, and skeletal muscle. The metabolic flexibility of the heart and its ability to switch between different energy substrates play a crucial role in maintaining cardiac function and overall metabolic homeostasis. Gaining a comprehensive understanding of how metabolic disorders disrupt cardiac metabolism is crucial, as it plays a pivotal role in the development and progression of cardiac diseases. The emerging understanding of the heart as a metabolic and endocrine organ highlights its essential contribution to whole body metabolic regulation and offers new insights into the pathogenesis of metabolic diseases, such as obesity, diabetes, and cardiovascular disorders. In this review, we provide an in-depth exploration of the heart's metabolic and endocrine functions, emphasizing its role in systemic metabolism and the interplay between the heart and other metabolic organs. Furthermore, emerging evidence suggests a correlation between heart disease and other conditions such as aging and cancer, indicating that the metabolic dysfunction observed in these conditions may share common underlying mechanisms. By unraveling the complex mechanisms underlying cardiac metabolism, we aim to contribute to the development of novel therapeutic strategies for metabolic diseases and improve overall cardiovascular health.

The association of serum adiponectin level with activities of daily living in hospitalized elderly patients with heart failure

BACKGROUND

Several studies have reported a relationship between elevated serum adiponectin levels and poor outcomes in patients with heart failure (HF). However, data on the activities of daily living (ADL) in elderly patients with HF are limited.

METHODS

We evaluated 218 hospitalized elderly (≥65 years) patients with HF who underwent a comprehensive cardiac rehabilitation (CR) program during hospitalization. Serum adiponectin levels were measured before discharge. The Barthel index (BI) score was evaluated at discharge. Low ADL was defined as a BI score < 85.

RESULTS

Serum adiponectin levels were significantly associated with low ADL [p = 0.03; odds ratio (OR), 1.024, per 1.0 μg/mL increase]. In logistic or regression analyses adjusted for age, sex, body mass index, and estimated glomerular filtration rate, high adiponectin levels (≥16.2 μg/mL) were significantly associated with low ADL (p = 0.04; OR, 2.53), malnutrition (p < 0.01; OR, 2.88), and 6-min walk distance (p = 0.04; β = -17.5). In the multivariate analysis adjusted for conventional risk factors of low ADL, high adiponectin levels were also significantly associated with low ADL (p = 0.03; OR, 2.68). In the stepwise forward selection procedure, a high adiponectin level was an independent determinant of low ADL (p = 0.02; R2 = 0.0262). Both net reclassification improvement (0.53; p < 0.01) and integrated discrimination improvement (0.02; p = 0.01) improved significantly after the addition of high adiponectin level to conventional risk factors. In the regression analysis adjusted for age and sex, serum adiponectin levels were significantly (p < 0.0025) negatively associated with abdominal visceral and subcutaneous adipose tissue areas, body weight, body mass index, and serum triglyceride levels.

CONCLUSIONS

High serum adiponectin levels were not only significantly associated with an increased risk of low ADL, but also with an increased risk of malnutrition and low physical activity in elderly patients with HF after the in-hospital CR program.

The correlation between erectile function and adiponectin levels in men with late-onset hypogonadism

Aim: This study investigated the relationship between erectile dysfunction (ED) and adiponectin levels in hypogonadal men.Methods: In this study, 218 patients with hypogonadism (mean age: 65.1 ± 8.3 years) were enrolled. All patients underwent physical examinations, with measurement of body mass index, body fat ratio, and waist circumference. The erectile function was assessed using the sexual health inventory for men (SHIM) scoring system. Blood biochemical profiles such as free testosterone, fasting blood glucose, and lipid profile including adiponectin levels were measured. All patients were divided into two groups based on their SHIM score: normal to moderate ED (SHIM score ≥ 12) and severe ED (SHIM score < 12), and the factors associated with severe ED were determined. Patients with severe ED were divided into two groups based on adiponectin levels (cutoff value of 7.0 μg/mL), and their basic characteristics were compared between these two groups.Results: The severe ED group was older and had higher adiponectin levels. In patients with severe ED, various metabolic parameters were significantly worse in the low adiponectin groups than in the non-low adiponectin group.Conclusions: The risk of developing cardiovascular diseases is extremely high in hypogonadal men with severe ED who had lower serum adiponectin levels.

Aldehyde dehydrogenase 2 augments adiponectin signaling in coronary angiogenesis in HFpEF associated with diabetes

4-hydroxy-2-nonenal (4HNE), an oxidative stress byproduct, is elevated in diabetes which decreases coronary angiogenesis, and this was rescued by the 4HNE detoxifying enzyme, aldehyde dehydrogenase 2 (ALDH2). Adiponectin (APN), an adipocytokine, has pro-angiogenic properties and its loss of function is critical in diabetes and its complications. Coronary endothelial cell (CEC) damage is the initiating step of diabetes-mediated heart failure with preserved ejection fraction (HFpEF) pathogenesis. Thus, we hypothesize that ALDH2 restores 4HNE-induced downregulation of APN signaling in CECs and subsequent coronary angiogenesis in diabetic HFpEF. Treatment with disulfiram, an ALDH2 inhibitor, exacerbated 4HNE-mediated decreases in APN-induced increased coronary angiogenesis and APN-signaling cascades, whereas pretreatment with alda1, an ALDH2 activator, rescued the effect of 4HNE. We employed control mice (db/m), spontaneous type-2 diabetic mice (db/db), ALDH2*2 knock-in mutant mice with intrinsic low ALDH2 activity (AL), and diabetic mice with intrinsic low ALDH2 activity (AF) mice that were created by crossing db/db and AL mice to test our hypothesis in vivo. AF mice exhibited heart failure with preserved ejection fraction (HFpEF)/severe diastolic dysfunction at 6 months with a preserved systolic function compared with db/db mice as well as 3 months of their age. Decreased APN-mediated coronary angiogenesis, along with increased circulatory APN levels and decreased cardiac APN signaling (index of APN resistance) were higher in AF mice relative to db/db mice. Alda1 treatment improved APN-mediated angiogenesis in AF and db/db mice. In summary, 4HNE-induces APN resistance and a subsequent decrease in coronary angiogenesis in diabetic mouse heart which was rescued by ALDH2.

The Impact of Obesity in Heart Failure

Overweight and obesity adversely impact cardiac structure and function, affecting systolic and diastolic ventricular function. Epidemiologic studies have documented an obesity paradox in large heart failure cohorts, where overweight and obese individuals with established heart failure have a better short- and medium-term prognosis compared with leaner patients; this relationship is strongly impacted by level of cardiorespiratory fitness. There are implications for therapies aimed at increasing lean mass as well as weight loss and improvements in quality of diet for the prevention and treatment of heart failure and concomitant obesity to improve cardiorespiratory fitness.

Relationship between Adipokines and Cardiovascular Ultrasound Parameters in Metabolic-Dysfunction-Associated Fatty Liver Disease

(1) Background: The role of adipokines such as adiponectin and visfatin in metabolic-dysfunction-associated fatty liver disease (MAFLD) and cardiovascular disease remains unclear. Therefore, we aim to assess serum adiponectin and visfatin levels in MAFLD patients and associated cardiovascular parameters. (2) Methods: A cross-sectional study involving 80 participants (40 MAFLD patients, 40 controls), recruited between January and September 2020, was conducted, using both hepatic ultrasonography and SteatoTestTM to evaluate hepatic steatosis. Echocardiographic and Doppler parameters were assessed. Serum adipokines were measured using ELISA kits. (3) Results: Adiponectin and visfatin levels were not significantly different in MAFLD vs. controls. Visfatin was associated with mean carotid intima-media thickness (p-value = 0.047), while adiponectin was associated with left ventricular ejection fraction (LVEF) (p-value = 0.039) and E/A ratio (p-value = 0.002) in controls. The association between adiponectin and E/A ratio was significant in the univariate analysis at 95% CI (0.0049–0.1331, p-value = 0.035), but lost significance after the multivariate analysis. Although LVEF was not associated with adiponectin in the univariate analysis, significant values were observed after the multivariate analysis (95% CI (−1.83–−0.22, p-value = 0.015)). (4) Conclusions: No significant difference in serum adiponectin and visfatin levels in MAFLD patients vs. controls was found. Interestingly, although adiponectin levels were not associated with LVEF in the univariate analysis, a significant inversely proportional association was observed after the multivariate analysis.

The Impact of Obesity in Heart Failure

Obesity has reached worldwide epidemic proportions, adversely impacting health on a global scale. Overweight and obesity adversely impact cardiac structure and function, affecting systolic and diastolic ventricular function. Studies and meta-analyses have documented an obesity paradox in large heart failure cohorts, where overweight and obese individuals with established heart failure have a better short- and medium-term prognosis compared with lean patients; this relationship is strongly impacted by level of cardiorespiratory fitness. There are implications for therapies aimed at increasing lean and muscle mass, and weight loss, for the prevention and treatment of compared with in patients with concomitant obesity.

Elevated Plasma Adiponectin Levels Are Associated with Abnormal Corrected QT Interval in Patients with Stable Angina

Low-circulating levels of adiponectin (ADPN) are associated with obesity, diabetes mellitus, and coronary artery disease. On the contrary, some studies have demonstrated a link between relatively high levels of plasma ADPN and heart failure, atrial fibrillation, and adverse outcome. However, little is known about the relationship between ADPN level and prolonged QT interval. The aim of this study was to investigate the association between plasma ADPN levels and prolonged QT interval in patients with stable angina.In this retrospective study, because the diverse disease severity and condition of the study population may have affected the results, we chose individuals with stable angina. Plasma ADPN concentrations were measured using enzyme-linked immunosorbent assays. A 12-lead ECG recording was obtained from each patient.We enrolled 479 stable-angina patients. Patients with an abnormal corrected QT (QTc) interval had higher median plasma ADPN levels than those with normal QTc intervals. Age- and sex-adjusted ADPN levels were positively associated with heart rate, QTc interval, left ventricular mass index, and creatinine but negatively associated with left ventricular ejection fraction, waist circumference, current smoking, total cholesterol, triglycerides, low-density lipoprotein cholesterol, albumin, and estimated glomerular filtration rate. A multiple logistic regression analysis revealed ADPN as an independent association factor for abnormal QTc interval. Increasing concentrations of sex-specific ADPN were independently and significantly associated with abnormal QTc interval, even after full adjustment of known biomarkers.Our results indicate that ADPN may play a role in the pathogenesis of abnormal QTc interval in patients with stable angina.

Clinical and Humoral Determinants of Congestion in Heart Failure: Potential Role of Adiponectin

BACKGROUND

Some patients with heart failure (HF) are more prone to systemic congestion than others. The goal of this study was to identify clinical and humoral factors linked to congestion and its prognostic impact in HF patients.

METHODS

A total of 371 advanced HF patients underwent physical examination, echocardiography, right heart catheterization, blood samplings, and Minnesota Living with HF Questionnaire. Subjects were followed-up for adverse events (death, urgent transplantation, or assist device implantation without heart transplantation).

RESULTS

Thirty-one percent of patients were classified as prone to congestion. During a median follow-up of 1,093 days, 159 (43%) patients had an adverse event. In the Cox analysis, the congestion-prone (CP) status was associated with a 43% higher event risk. The CP status was strongly (p ˂ 0.001) associated with body weight loss, right ventricular dysfunction (RVD), dilated inferior vena cava (IVC), diuretics, and beta-blockers prescription and the majority of tested hormones in the univariate analysis. In the multivariate analysis, the only independent variables associated with the CP status were adiponectin, albumin, IVC diameter, and RVD. Adiponectin by itself was predictive of adverse events. In a multivariate model, CP status was no longer predictive of adverse events, in contrast to adiponectin.

CONCLUSIONS

CP patients experienced more severe symptoms and had shorter survival. Potential role of adiponectin, a new independent predictor of CP status, should be further examined.

Heart Failure With Preserved Ejection Fraction and Adipose Tissue: A Story of Two Tales

Heart failure with preserved ejection fraction (HFpEF) is characterized by signs and symptoms of heart failure in the presence of a normal left ventricular ejection fraction. Although it accounts for up to 50% of all clinical presentations of heart failure, there are no evidence-based therapies for HFpEF to reduce morbidity and mortality. Additionally there is a lack of mechanistic understanding about the pathogenesis of HFpEF. HFpEF is associated with many comorbidities (such as obesity, hypertension, type 2 diabetes, atrial fibrillation, etc.) and is coupled with both cardiac and extra-cardiac abnormalities. Large outcome trials and registries reveal that being obese is a major risk factor for HFpEF. There is increasing focus on investigating the link between obesity and HFpEF, and the role that the adipose tissue and the heart, and the circulating milieu play in development and pathogenesis of HFpEF. This review discusses features of the obese-HFpEF phenotype and highlights proposed mechanisms implicated in the inter-tissue communication between adipose tissue and the heart in obesity-associated HFpEF.

Association between elevated adiponectin level and adverse outcomes in patients with heart failure: a systematic review and meta-analysis

Studies regarding the prognostic value of circulating adiponectin level in patients with heart failure are conflicting. The aim of this meta-analysis was to evaluate the association between elevated circulating adiponectin level and adverse outcomes in patients with heart failure. We searched PubMed and Embase databases from their inception to June 2018. Original observational studies that investigated the prognostic value of adiponectin in heart failure patients and reported all-cause mortality or combined endpoints of death/readmission as outcome measure were included. Pooled risk ratio (RR) with 95% confidence intervals (CI) were estimated by higher versus lower circulating adiponectin level. A total of 7 studies involving 862 heart failure patients were identified. Meta-analysis showed that heart failure patients with higher adiponectin level had significantly increased risk of all-cause mortality (RR 2.05; 95%CI 1.22–3.43) after adjustment for potential confounders. In addition, higher adiponectin level was associated with an increased risk of the combined endpoints of death/readmission (RR 2.22; 95%CI 1.38–3.57). Elevated baseline circulating adiponectin level is possibly associated with an increased risk of all-cause mortality and the combined endpoints of death/readmission in patients with heart failure. Determination of circulating adiponectin level has potential to improve risk stratification in heart failure patients.

Comparative symptom biochemistry between moderate and advanced heart failure

BACKGROUND

We have a limited understanding of the biological underpinnings of symptoms in heart failure (HF).

OBJECTIVES

The purpose of this paper was to compare relationships between peripheral biomarkers of HF pathogenesis and physical symptoms between patients with advanced versus moderate HF.

METHODS

This was a two-stage phenotype sampling cohort study wherein we examined patients with advanced HF undergoing ventricular assist device implantation in the first stage, and then patients with moderate HF (matched adults with HF not requiring device implantation) in the second stage. Linear modeling was used to compare relationships among biomarkers and physical symptoms between cohorts.

RESULTS

Worse myocardial stress, systemic inflammation and endothelial dysfunction were associated with worse physical symptoms in moderate HF (n=48), but less physical symptom burden in advanced HF (n=48).

CONCLUSIONS

Where patients are in the HF trajectory needs to be taken into consideration when exploring biological underpinnings of physical HF symptoms.

The Non-cardiomyocyte Cells of the Heart. Their Possible Roles in Exercise-Induced Cardiac Regeneration and Remodeling

The non-cardiomyocyte cellular microenvironment of the heart includes diverse types of cells of mesenchymal origin. During development, the majority of these cells derive from the epicardium, while a subset derives from the endothelium/endocardium and neural crest derived mesenchyme. This subset includes cardiac fibroblasts and telocytes, the latter of which are a controversial type of "connecting cell" that support resident cardiac progenitors in the postnatal heart. Smooth muscle cells, pericytes, and endothelial cells are also present, in addition to adipocytes, which accumulate as epicardial adipose connective tissue. Furthermore, the heart harbors many cells of hematopoietic origin, such as mast cells, macrophages, and other immune cell populations. Most of these control immune reactions and inflammation. All of the above-mentioned non-cardiomyocyte cells of the heart contribute to this organ's well-orchestrated physiology. These cells also contribute to regeneration as a result of injury or age, in addition to tissue remodeling triggered by chronic disease or increased physical activity (exercise-induced cardiac growth). These processes in the heart, the most important vital organ in the human body, are not only fascinating from a scientific standpoint, but they are also clinically important. It is well-known that regular exercise can help prevent many cardiovascular diseases. However, the precise mechanisms underpinning myocardial remodeling triggered by physical activity are still unknown. Surprisingly, exercise-induced adaptation mechanisms are often identical or very similar to tissue remodeling caused by pathological conditions, such as hypertension, cardiac hypertrophy, and cardiac fibrosis. This review provides a summary of our current knowledge regarding the cardiac cellular microenvironment, focusing on the clinical applications this information to the study of heart remodeling during regular physical exercise.

The Role of Serum Adiponectin for Outcome Prediction in Patients with Dilated Cardiomyopathy and Advanced Heart Failure

Clinical interpretation of patients' plasma adiponectin (APN) remains challenging; its value as biomarker in dilated cardiomyopathy (DCM) is equivocal. We evaluated whether circulating APN level is an independent predictor of composite outcome: death, left ventricle assist device (LVAD) implantation, and heart transplantation (HT) in patients with nonischemic DCM. 57 patients with nonischemic DCM (average LV diastolic diameter 6.85 cm, LV ejection fraction 26.63%, and pulmonary capillary wedge pressure 22.06  mmHg) were enrolled. Patients underwent echocardiography, right heart catheterization, and endomyocardial biopsy. During a mean follow-up of 33.42 months, 15 (26%) patients died, 12 (21%) patients underwent HT, and 8 (14%) patients were implanted with LVAD. APN level was significantly higher in patients who experienced study endpoints (23.4 versus 10.9 ug/ml, p = 0.01). APN was associated with worse outcome in univariate Cox proportional hazards model (HR 1.04, CI 1.02-1.07, p = 0.001) but lost significance adjusting for other covariates. Average global strain (AGS) is an independent outcome predictor (HR 1.42, CI 1.081-1.866, p = 0.012). Increased circulating APN level was associated with higher mortality and may be an additive prognostic marker in DCM with advanced HF. Combination of serum (APN, BNP, TNF-α) and echocardiographic (AGS) markers may increase the HF predicting power for the nonischemic DCM patients.

Obesity, body composition and cardiorespiratory fitness in heart failure with preserved ejection fraction

Obesity is defined as an excess body fat that impairs health and is associated with increased risk of heart failure (HF), particularly HF with preserved ejection fraction (HFpEF), evolving into a ‘HFpEF obesity phenotype’. The interplay between obesity and cardiorespiratory fitness, primary clinical parameters in HF, requires further exploration. The contribution of body composition compartments in the development and progress of HF has been the object of numerous studies. Here we focus on how fat mass and lean tissues affect cardiorespiratory fitness, with emphasis on their effects on peak oxygen consumption. Moreover, while several studies have focused on characterization of body composition compartments, here we describe also recent findings related to abnormal and/or dysfunctional lean mass, especially in HFpEF.

Pleiotropic effects of niacin: Current possibilities for its clinical use

Niacin was the first hypolipidemic drug to significantly reduce both major cardiovascular events and mortality in patients with cardiovascular disease. Niacin favorably influences all lipoprotein classes, including lipoprotein[a],and belongs to the most potent hypolipidemic drugs for increasing HDL-C. Moreover, niacin causes favorable changes to the qualitative composition of lipoprotein HDL. In addition to its pronounced hypolipidemic action, niacin exerts many other, non-hypolipidemic effects (e.g., antioxidative, anti-inflammatory, antithrombotic), which favorably influence the development and progression of atherosclerosis. These effects are dependent on activation of the specific receptor HCA2. Recent results published by the two large clinical studies, AIM-HIGH and HPS2-THRIVE, have led to the impugnation of niacin's role in future clinical practice. However, due to several methodological flaws in the AIM-HIGH and HPS2-THRIVE studies, the pleiotropic effects of niacin now deserve thorough evaluation. This review summarizes the present and possible future use of niacin in clinical practice in light of its newly recognized pleiotropic effects.

Plasma Levels of Fatty Acid-Binding Protein 4, Retinol-Binding Protein 4, High-Molecular-Weight Adiponectin, and Cardiovascular Mortality Among Men With Type 2 Diabetes: A 22-Year Prospective Study

OBJECTIVE

To examine select adipokines, including fatty acid-binding protein 4, retinol-binding protein 4, and high-molecular-weight (HMW) adiponectin in relation to cardiovascular disease (CVD) mortality among patients with type 2 diabetes mellitus.

APPROACH AND RESULTS

Plasma levels of fatty acid-binding protein 4, retinol-binding protein 4, and HMW adiponectin were measured in 950 men with type 2 diabetes mellitus in the Health Professionals Follow-up Study. After an average of 22 years of follow-up (1993-2015), 580 deaths occurred, of whom 220 died of CVD. After multivariate adjustment for covariates, higher levels of fatty acid-binding protein 4 were significantly associated with a higher CVD mortality: comparing extreme tertiles, the hazard ratio and 95% confidence interval of CVD mortality was 1.78 (1.22-2.59; P trend=0.001). A positive association was also observed for HMW adiponectin: the hazard ratio (95% confidence interval) was 2.07 (1.42-3.06; P trend=0.0002), comparing extreme tertiles, whereas higher retinol-binding protein 4 levels were nonsignificantly associated with a decreased CVD mortality with an hazard ratio (95% confidence interval) of 0.73 (0.50-1.07; P trend=0.09). A Mendelian randomization analysis suggested that the causal relationships of HMW adiponectin and retinol-binding protein 4 would be directionally opposite to those observed based on the biomarkers, although none of the Mendelian randomization associations achieved statistical significance.

CONCLUSIONS

These data suggest that higher levels of fatty acid-binding protein 4 and HMW adiponectin are associated with elevated CVD mortality among men with type 2 diabetes mellitus. Biological mechanisms underlying these observations deserve elucidation, but the associations of HMW adiponectin may partially reflect altered adipose tissue functionality among patients with type 2 diabetes mellitus.

Adiponectin resistance in skeletal muscle: pathophysiological implications in chronic heart failure

Skeletal muscle wasting is a common complication of chronic heart failure (CHF) and linked to poor patient prognosis. In recent years, adiponectin was postulated to be centrally involved in CHF-associated metabolic failure and muscle wasting. This review discusses current knowledge on the role of adiponectin in CHF. Particular emphasis will be given to the complex interaction mechanisms and the intracellular pathways underlying adiponectin resistance in skeletal muscle of CHF patients. In this review, we propose that the resistance process is multifactorial, integrating abnormalities emanating from insulin signalling, mitochondrial biogenesis, and ceramide metabolism.

Adipocytokines in renal transplant recipients

In the last two decades, perceptions about the role of body fat have changed. Adipocytes modulate endocrine and immune homeostasis by synthesizing hundreds of hormones, known as adipocytokines. Many studies have been investigating the influences and effects of these adipocytokines and suggest that they are modulated by the nutritional and immunologic milieu. Kidney transplant recipients (KTRs) are a unique and relevant population in which the function of adipocytokines can be examined, given their altered nutritional and immune status and subsequent dysregulation of adipocytokine metabolism. In this review, we summarize the recent findings about four specific adipocytokines and their respective roles in KTRs. We decided to evaluate the most widely described adipocytokines, including leptin, adiponectin, visfatin and resistin. Increasing evidence suggests that these adipocytokines may lead to cardiovascular events and metabolic changes in the general population and may also increase mortality and graft loss rate in KTRs. In addition, we present findings on the interrelationship between serum adipocytokine levels and nutritional and immunologic status, and mechanisms by which adipocytokines modulate morbidity and outcomes in KTRs.

Adiponectin: key role and potential target to reverse energy wasting in chronic heart failure

The concept of skeletal muscle myopathy as a main determinant of exercise intolerance in chronic heart failure (HF) is gaining acceptance. Symptoms that typify HF patients, including shortness of breath and fatigue, are often directly related to the abnormalities of the skeletal muscle in HF. Besides muscular wasting, alterations in skeletal muscle energy metabolism, including insulin resistance, have been implicated in HF. Adiponectin, an adipocytokine with insulin-sensitizing properties, receives increasing interest in HF. Circulating adiponectin levels are elevated in HF patients, but high levels are paradoxically associated with poor outcome. Previous analysis of m. vastus lateralis biopsies in HF patients highlighted a striking functional adiponectin resistance. Together with increased circulating adiponectin levels, adiponectin expression within the skeletal muscle is elevated in HF patients, whereas the expression of the main adiponectin receptor and genes involved in the downstream pathway of lipid and glucose metabolism is downregulated. In addition, the adiponectin-related metabolic disturbances strongly correlate with aerobic capacity (VO2 peak), sub-maximal exercise performance and muscle strength. These observations strengthen our hypothesis that adiponectin and its receptors play a key role in the development and progression of the "heart failure myopathy". The question whether adiponectin exerts beneficial rather than detrimental effects in HF is still left unanswered. This current research overview will elucidate the emerging role of adiponectin in HF and suggests potential therapeutic targets to tackle energy wasting in these patients.

Cardio-adipose tissue cross-talk: relationship between adiponectin, plasma pro brain natriuretic peptide and incident heart failure

AIMS

There is increasing evidence of cross-talk between the heart, body metabolism, and adipose tissue, but the precise mechanisms are poorly understood. Natriuretic peptides (NPs) have recently emerged as the prime candidate for a mediator. In patients with heart failure (HF), infusion of NPs increases adiponectin secretion, indicating that NPs may improve adipose tissue function and in this way function as a cardio-protective agent in HF. Accordingly we investigated the interplay between plasma adiponectin, plasma proBNP, and development of HF.

METHODS AND RESULTS

We prospectively followed 5574 randomly selected men and women from the community without ischaemic heart disease or HF. Plasma adiponectin and proBNP were measured at study entry. Median follow-up time was 8.5 years (interquartile range 8.0-9.1 years). During follow-up 271 participants developed symptomatic HF. Plasma adiponectin and proBNP were strongly associated (P < 0.001). Participants with increasing adiponectin had increased risk of incident HF (P < 0.001). After adjustment for confounding risk factors (including age, gender, smoking status, body mass ratio, waist-hip ratio, glucose, glycated haemoglobin, systolic and diastolic blood pressure, lipid profile, high sensitivity C-reactive protein, estimated glomerular filtration rate, and physical activity) by Cox regression analysis, adiponectin remained an independent predictor of HF: the hazard ratio (HR) per 1 standard deviation (SD) increase in adiponectin was 1.20 [95% confidence interval (CI) 1.06-1.30; P = 0.003]. However, the association vanished when plasma proBNP was included in the analysis, HR 1.08 (95% CI 0.95-1.23; P = 0.26).

CONCLUSIONS

In conclusion, plasma adiponectin and proBNP are strongly associated. Increasing plasma adiponectin is associated with increased risk of HF. However, concomitantly elevated proBNP levels appear to explain the positive association between adiponectin and risk of HF.

Adiponectin as a routine clinical biomarker

Adiponectin is a protein synthesized and secreted predominantly by adipocytes into the peripheral blood. However, circulating adiponectin level is inversely related with body weight, especially visceral fat accumulation. The mechanism of this paradoxical relation remains obscure. Low circulating adiponectin concentrations (hypoadiponectinemia; <4 μg/mL) are associated with a variety of diseases, including dysmetabolism (type 2 diabetes, insulin resistance, hypertension, dyslipidemia, metabolic syndrome, hyperuricemia), atherosclerosis (coronary artery disease, stroke, peripheral artery disease), sleep apnea, non-alcoholic fatty liver disease, gastritis and gastro-esophageal reflux disease, inflammatory bowel diseases, pancreatitis, osteoporosis, and cancer (endometrial cancer, postmenopausal breast cancer, leukemia, colon cancer, gastric cancer, prostate cancer). On the other hand, hyperadiponectinemia is associated with cardiac, renal and pulmonary diseases. This review article focuses on the significance of adiponectin as a clinical biomarker of obesity-related diseases. Routine measurement of adiponectin in patients with lifestyle-related diseases is highly recommended.

Clinical use of adiponectin as a marker of metabolic dysregulation

Adiponectin concentrations exhibit strong cross-sectional relationships with obesity, inflammation, and diabetes. Adiponectin concentrations have been extensively evaluated as epidemiologic markers of diabetes and cardiovascular disease risk. In the present review we will provide an overview of these epidemiologic relationships as the backdrop for an evaluation of the clinical applications of adiponectin measurements. These include using adiponectin as an indicator of need for preventive or therapeutic intervention, as a predictor of response to therapy, and as a marker of therapeutic effectiveness. These efforts are laying the groundwork for the transition of adiponectin measurements from the laboratory to the clinic.

Impact of adiponectin and leptin on long-term adverse events in Japanese patients with acute myocardial infarction. Results from the Nagoya Acute Myocardial Infarction Study (NAMIS)

BACKGROUND

Low adiponectin levels and high leptin levels are associated with a high incidence of developing cardiovascular disease. However, the relationship between the levels of these adipokines and the development of adverse events after acute myocardial infarction (AMI) remains unclear.

METHODS AND RESULTS

This study enrolled 724 Japanese subjects with AMI who underwent successful emergency percutaneous coronary intervention (PCI). Their serum adiponectin and leptin levels were measured 7 days after AMI onset. There were 63 adverse events during the 3-year follow-up. The levels of adiponectin and leptin and the leptin to adiponectin ratio, were significantly associated with adverse events [hazard ratio 2.08 (95% confidence interval (CI) 1.33-3.24), P=0.001; hazard ratio 0.62 (95% CI 0.43-0.90), P=0.012; hazard ratio 0.59 (95% CI 0.45-0.76), P<0.001, respectively]. The leptin to adiponectin ratio remained a significant independent predictor of adverse events during long-term follow-up in a multivariable analysis [adjusted hazard ratio 0.60 (95% CI 0.43-0.83), P=0.002].

CONCLUSIONS

Higher adiponectin and lower leptin levels are associated with a high incidence of adverse events in Japanese patients after AMI, and the leptin to adiponectin ratio independently predicts prognosis after AMI.

The relationship between adiponectin and left ventricular mass index varies with the risk of left ventricular hypertrophy

BACKGROUND

Adiponectin directly protects against cardiac remodeling. Despite this beneficial effect, most epidemiological studies have reported a negative relationship between adiponectin level and left ventricular mass index (LVMI). However, a positive relationship has also been reported in subjects at high risk of left ventricular hypertrophy (LVH). Based on these conflicting results, we hypothesized that the relationship between serum adiponectin level and LVMI varies with the risk of LVH.

METHODS

A community-based, cross-sectional study was performed on 1414 subjects. LVMI was measured by echocardiography. Log-transformed adiponectin levels (Log-ADPN) were used for the analysis.

RESULTS

Serum adiponectin level had a biphasic distribution (an increase after a decrease) with increasing LVMI. Although Log-ADPN did not correlate with LVMI, Log-ADPN was modestly associated with LVMI in the multivariate analysis (β = 0.079, p = 0.001). The relationship between adiponectin level and LVMI was bidirectional according to the risk of LVH. In normotensive subjects younger than 50 years, Log-ADPN negatively correlated with LVMI (r = -0.204, p = 0.005); however, Log-ADPN positively correlated with LVMI in ≥50-year-old obese subjects with high arterial stiffness (r = 0.189, p = 0.030). The correlation coefficient between Log-ADPN and LVMI gradually changed from negative to positive with increasing risk factors for LVH. The risk of LVH significantly interacted with the relationship between Log-ADPN and LVMI. In the multivariate analysis, Log-ADPN was associated with LVMI in the subjects at risk of LVH; however, Log-ADPN was either not associated or negatively associated with LVMI in subjects at low risk of LVH.

CONCLUSION

Adiponectin level and LVMI are negatively associated in subjects at low risk of LVH and are positively associated in subjects at high risk of LVH. Therefore, the relationship between adiponectin and LVMI varies with the risk of LVH.

Cachexia in chronic heart failure: endocrine determinants and treatment perspectives

It is well documented in the current literature that chronic heart failure is often associated with cachexia, defined as involuntary weight loss of 5 % in 12 month or less. Clinical studies unraveled that the presence of cachexia decreases significantly mean survival of the patient. At the molecular level mainly myofibrillar proteins are degraded, although a reduced protein synthesis may also contribute to the loss of muscle mass. Endocrine factors clearly regulate muscle mass and function by influencing the normally precisely controlled balance between protein breakdown and protein synthesis The aim of the present article is to review the knowledge in the field with respect to the role of endocrine factors for the regulation of cachexia in patients with CHF and deduce treatment perspectives.

Cardiovascular-metabolic impact of adiponectin and aquaporin

Visceral fat accumulation is located upstream of metabolic syndrome. Recent progress in adipocyte biology has clarified the molecular mechanism for pathophysiology of metabolic syndrome and its related disorders. In this review we summarize adiponectin and aquaporin 7 (AQP7) in the role of metabolic syndrome and cardiovascular diseases.

Increase of high molecular weight adiponectin in hypertensive pregnancy was correlated with brain-type natriuretic peptide stimulation on adipocyte

BACKGROUND

High-molecular weight (HMW)-adiponectin is an active multimer for insulin sensitivity and anti-inflammatory reactions. We compared the ratio of serum total and HMW-adiponectin with brain-type natriuretic peptide (BNP) and other adipocytokines in normal pregnancy and pregnancy-induced hypertension (PIH). Effect of BNP on the secretion of adiponectin from cultured adipocytes was also examined.

METHODS

The three study groups consisted of 44 non-pregnant women, 40 normal (healthy) pregnant women over 28weeks gestation and 29 patients with severe PIH. Adiponectin (protease-pretreated for HMW), BNP-N-terminal, leptin, and monocyte chemoattractant protein (MCP)-1 were measured with ELISA. Pre-adipocytes were differentiated to matured adipocytes and cultured with recombinant-BNP addition.

RESULTS

HMW-to-total adiponectin ratio (HMW-ratio) was lower in normal pregnancy than in non-pregnant, and significantly higher in PIH than normal pregnancies. BNP-N-terminal showed positive correlation with HMW-adiponectin and HMW-ratio. Leptin and MCP-1 showed positive correlation with HMW-adiponectin, but not with HMW-ratio. Adiponectin in the supernatant of adipocyte cultures and intracellular cyclic-GMP was increased in dose-dependent manner in response to BNP.

CONCLUSION

The observed increase in the HMW-adponectin ratio in subjects with PIH may reflect a functional increase of adiponectin in the pathophysiology of PIH. Additionally, this increase seemed to be related to BNP via stimulation of adipocytes.

Impact of obesity on plasma B-type natriuretic peptide levels in Japanese community-based subjects

The plasma B-type natriuretic peptide (BNP) concentration was recently shown to be inversely correlated with body mass index (BMI). However, very few attempts have been made to associate abdominal obesity and BNP in the Japanese general population. Here, we conducted a cross-sectional study, and examined 339 male and 429 female residents without heart disease in a rural Japanese community who received an annual health checkup in 2006. BNP was inversely associated with both BMI and abdominal circumference (AC) in the age-adjusted regression analysis (p < 0.05). Following adjustment for traditional risk factors, multiple regression analysis revealed that BNP was negatively correlated with AC (p < 0.05), but not BMI. Although metabolic syndrome was not associated with BNP levels, AC had an influence on low BNP levels in the multiple regression analysis using both AC and BMI concurrently (p < 0.05 for AC and p > 0.60 for BMI). These effects were more prominent in men than in women. Collectively, plasma BNP levels are inversely related with obesity, as measured by AC, in Japanese community-based subjects.

Elevated resistin opposed to adiponectin or angiogenin plasma levels as a strong, independent predictive factor for the occurrence of major adverse cardiac and cerebrovascular events in patients with stable multivessel coronary artery disease over 1-year follow-up

Background

Adipokines such as adiponectin and resistin, as well as angiogenin, may be associated with inflammation and atherosclerosis. The relationship between their levels and prognosis in high risk patients is, however, still unclear. The aim of this study was to evaluate the prognostic value of these adipokines in patients with stable multivessel coronary artery disease (MCAD).

Material/Methods

The study group comprised 107 MCAD patients (74% males, mean age 63±8 years). Adiponectin, resistin and angiogenin plasma levels were measured at admission and after 1-year follow-up. Primary end point (major adverse cardiac and cerebrovascular events – MACCE) was defined as cardiac death, nonfatal myocardial infarction, stroke, and hospitalization for angina or heart failure over a 1-year period.

Results

After 1-year follow-up, 9 (8%) patients died, all from cardiovascular causes. Primary end point was experienced by 32% of patients. Surgical treatment (CABG) was received by 51% of patients, while 49% were treated medically alone. Total cholesterol concentration levels ≥173 mg/dl were associated with a 7-fold increase (OR 7.3; 95% CI, 1.6–33.0); LDL ≥93.5 mg/dl with a 16-fold increase (OR 16.3; 95% CI, 2.8–93.8), and resistin ≥17.265 ng/ml with a 13-fold increase in MACCE risk (OR 13.5; 95% CI, 2.3–80.3). In multivariate analysis, a medical treatment strategy (p=0.001), a higher CCS class (p=0.004), resistin levels (p=0.003) and a higher Gensini score (p=0.03) were independent predictors of MACCE.

Conclusions

In stable patients with MCAD, elevated plasma resistin (as opposed to adiponectin or angiogenin) is a strong, independent predictive factor for the occurrence of MACCE over 1-year follow-up.

Association of increased parathyroid hormone with neuroendocrine activation and endothelial dysfunction in elderly men with heart failure

High PTH levels have been reported in patients with chronic heart failure (CHF). Similarly, its levels increase with aging and are related to impaired survival in elderly adults. However, its relationship with neuroendocrine activation and endothelial dysfunction in CHF has not been previously studied. Seventy-three CHF males with New York Heart Association (NYHA) classes II and III and 20 control subjects aged ≥ 55 yr were recruited. PTH, 25-hydroxyvitamin D [25(OH)D], N-terminal pro-brain natriuretic peptide (NT-pro-BNP), adiponectin, and osteoprotegerin were measured. Endothelial function (brachial flow mediated dilation), echocardiography, physical performance, and quality of life were assessed, as well. CHF patients had markedly increased serum PTH (77 ± 33 vs 40 ± 11 pg/ml, p<0.0001), NT-pro-BNP [1809 (2742) vs 67 (74) pg/ml, p<0.0001], adiponectin (17 ± 9 vs 10 ± 2 μg/ml, p<0.0001), osteoprotegerin, whereas 25(OH)D levels were decreased compared to controls. Increased PTH is positively correlated with NTpro- BNP (r=0.399, p<0.0001), adiponectin (r=0.398, p<0.0001), and osteoprotegerin, whereas negatively with 25(OH)D in CHF patients. Additionally, increased serum PTH was associated with endothelial dysfunction, echocardiographic variables of heart failure progression, impaired physical performance, and deteriorated quality of life. In a multivariate linear regression analysis, increased serum PTH was independently associated with neuroendocrine activation (NT-pro-BNP, adiponectin) and endothelial dysfunction in elderly CHF men (R2=0.455). Additionally, demonstrated relations with other well-established variables of heart failure severity suggest the potential role of serum PTH in the pathogenesis and non-invasive monitoring of heart failure progression. Future studies are needed to evaluate the predictive value of serum PTH for clinical outcomes as well as beneficial potential of PTH suppression in CHF patients.

Adiponectin provides cardiovascular protection in metabolic syndrome

Adipose tissue plays a central role in the pathogenesis of metabolic syndrome. Adiponectin (APN) is a bioactive adipocytokine secreted from adipocytes. Low plasma APN levels (hypoadiponectinemia) are observed among obese individuals and in those with related disorders such as diabetes, hypertension, and dyslipidemia. APN ameliorates such disorders. Hypoadiponectinemia is also associated with major cardiovascular diseases including atherosclerosis and cardiac hypertrophy. Accumulating evidence indicates that APN directly interacts with cardiovascular tissue and prevents cardiovascular pathology. Increasing plasma APN or enhancing APN signal transduction may be an ideal strategy to prevent and treat the cardiovascular diseases associated with metabolic syndrome. However, further studies are required to uncover the precise biological actions of APN.

Effects of adiponectin deficiency on structural and metabolic remodeling in mice subjected to pressure overload

Recent data suggest adiponectin, an adipocyte-derived hormone, affects development of heart failure in response to hypertension. Severe short-term pressure overload [1-3 wk of transverse aortic constriction (TAC)] in adiponectin(-/-) mice causes greater left ventricle (LV) hypertrophy than in wild-type (WT) mice, but conflicting results are reported regarding LV remodeling, with either increased or decreased LV end diastolic volume compared with WT mice. Here we assessed the effects of prolonged TAC on LV hypertrophy and remodeling. WT and adiponectin(-/-) mice were subjected to TAC and maintained for 6 wk. Regardless of strain, TAC induced similar LV hypertrophy ( approximately 70%) and upregulation of mRNA for heart failure marker genes. However, LV chamber size was dramatically different, with classic LV dilation in WT TAC mice but concentric LV hypertrophy in adiponectin(-/-) mice. LV end diastolic and systolic volumes were lower and ejection fraction higher in adiponectin(-/-) TAC mice compared with WT, indicating that adiponectin deletion prevented LV remodeling and deterioration in systolic function. The activities of marker enzymes of mitochondrial oxidative capacity were reduced in WT TAC mice by approximately 35%, whereas enzyme activities were maintained at sham levels in adiponectin(-/-) TAC mice. In conclusion, in WT mice, long-term pressure overload caused dilated LV hypertrophy accompanied by decreased activity of mitochondrial oxidative enzymes. Although adiponectin deletion did not affect LV hypertrophy, it prevented LV chamber remodeling and preserved mitochondrial oxidative capacity, suggesting that adiponectin plays a permissive role in mediating changes in cardiac structure and metabolism in response to pressure overload.

Exercise training reduces circulating adiponectin levels in patients with chronic heart failure

High adiponectin concentrations have emerged as an independent risk factor of outcome inpatients with CHF (chronic heart failure); however, modification of adiponectin in CHF patients has not been assessed to date. The aim of the present study was to investigate the effect of exercise training on adiponectin levels in CHF patients. A total of 80 patients with CHF due to systolic dysfunction were included. The effect of 4 months exercise training was studied in 46 patients,whereas the remaining 34 untrained CHF patients served as a sedentary control group. Circulating adiponectin concentrations, exercise capacity, anthropometric data and NT-proBNP (N-terminal pro-brain natriuretic peptide) levels were assessed. Adiponectin levels were significantly higher in CHF patients compared with healthy subjects [9.3 (7.1-16.1) and 4.9 (3.9-8.6) mg/l respectively;P=0.015]. Stratification of CHF patients according to tertiles of NT-proBNP revealed an increase in adiponectin with disease severity (P<0.0001). Exercise training reduced circulating adiponectin levels in CHF patients [10.7 (7.2-17.6) mg/l before training to 9.4 (5.9-14.8) mg/l after training;P=0.013], whereas no changes were observed in the sedentary CHF group [9.0 (7.0-13.5) mg/l before training and 10.1 (6.0-15.7) mg/l after a similar time interval]. A significant time x group interaction (P=0.008) was observed for the mean change in adiponectin between the trained and untrained CHF patients. Adiponectin concentrations were positively associated with NT-proBNP and HDL (high-density lipoprotein)-cholesterol and negatively correlated with BMI (body mass index), triacylglycerols and exercise capacity. In conclusion, circulating adiponectin concentrations are higher in CHF patients compared with healthy subjects and increase with disease severity.Exercise training for 4 months lowers circulating adiponectin levels.

Analysis of adiponectin gene polymorphisms in dilated cardiomyopathy in a Han Chinese population

Dilated cardiomyopathy (DCM) is a heart muscle disease characterized by ventricular chamber enlargement and systolic dysfunction with normal left ventricular wall thickness. The pathogenesis of DCM has been extensively studied for many years, but it remains elusive. Adiponectin is an adipocyte-derived cytokine with anti-inflammatory, antidiabetic, and antiatherogenic properties. To assess the role of adiponectin in DCM, we examined two single-nucleotide polymorphisms in the adiponectin gene, rs1501299 and rs2241766. A total of 203 DCM patients and 258 control subjects were recruited in this study and all single-nucleotide polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism. No statistically significant differences in genotype and allele frequencies were observed between DCM and controls with any of the adiponectin genetic variants. These data may provide evidence that adiponectin polymorphisms do not play a role in the susceptibility of DCM in the Han Chinese population.

Relationship between RANKL and neuroendocrine activation in elderly males with heart failure

The main cytokines regulating bone remodeling are the receptor activator of nuclear factor-κB ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG). Recent data have linked RANKL and OPG to cardiovascular disease as well. NT-pro-BNP and adiponectin are well-established biomarkers of heart failure reflecting neuroendocrine activation in this multi-complex disorder. The objective of this article was to investigate whether RANKL is associated with neuroendocrine activation in 75 elderly males with mild to moderate congestive heart failure (CHF) and left ventricular ejection fraction <40%. The control group consisted of 20 healthy male volunteers with matching age and body mass index (BMI). Serum RANKL (sRANKL), OPG, NT-pro-BNP, adiponectin, leptin, clinical, and echocardiography parameters were evaluated. In comparison to the control group, the CHF patients showed significantly increased sRANKL levels [126.8 (122.6) vs. 47.8 (44.4) pg/ml, P < 0.0001]. There was a significant relative risk of systolic CHF in elderly males associated with increased sRANKL above the calculated cut-off of 83 pg/ml [OR = 10.286 (95%CI 3.079-34.356), P < 0.0001; RR = 3.600 (95%CI = 1.482-8.747)]. In the CHF patients, the log-transformed values of sRANKL levels correlated positively with the log-transformed values of the serum NT-pro-BNP and adiponectin levels (P = 0.004, r = 0.326 and P = 0.037, r = 0. 241, respectively), while inversely correlated with the BMI and creatinine clearance (P = 0.015, r = -0.281 and P = 0.042, r = -0.236, respectively). In multivariate regression model, sRANKL was a significant determinant of NT-pro-BNP independent of age, BMI and creatinine clearance (P = 0.002, R (2) = 0.546). In conclusion, our study suggests that in elderly males with systolic heart failure sRANKL was significantly associated with parameters of neuroendocrine activation such as NT-pro-BNP and adiponectin. Further studies are needed to elucidate the potential role of sRANKL in the complex pathogenesis of heart failure.

Functional adiponectin resistance at the level of the skeletal muscle in mild to moderate chronic heart failure

BACKGROUND

Adiponectin is an antiinflammatory, insulin-sensitizing, and antiatherogenic adipocytokine that plays a fundamental role in energy homeostasis. In patients with chronic heart failure (CHF), high circulating adiponectin levels are associated with inverse outcome. Recently, adiponectin expression has been identified in human skeletal muscle fibers. We investigated the expression of adiponectin, the adiponectin receptors, and genes involved in the downstream lipid and glucose metabolism in the skeletal muscle of patients with CHF.

METHODS AND RESULTS

Muscle biopsies (vastus lateralis muscle) were obtained from 13 patients with CHF and 10 healthy subjects. mRNA transcript levels of adiponectin, adiponectin receptors (AdipoR1 and AdipoR2), and downstream adiponectin-related enzymes were quantified by real-time reverse transcriptase polymerase chain reaction. Adiponectin expression in the skeletal muscle of patients with CHF was 5-fold higher than in healthy subjects (P<0.001), whereas AdipoR1 was downregulated (P=0.005). In addition, the expression of the main genes involved in downstream pathway (peroxisome proliferator-activated receptor-alpha [PPAR-alpha] and both AMP-activated protein kinase-alpha1 and -alpha2 subunits) as well as their target genes in lipid (acyl-coenzyme A dehydrogenase C-14 to C-12 straight chain) and glucose metabolism (hexokinase-2) were significantly reduced in CHF. The strong positive correlation found between AdipoR1 and PPAR-alpha/AMP-activated protein kinase gene expression was confirmed in PPAR-alpha null mice, suggesting a cause-and-effect relationship. Immunohistochemical staining confirmed the presence of adiponectin in the skeletal muscle.

CONCLUSIONS

Despite increased adiponectin expression in the skeletal muscle, patients with CHF are characterized by downregulation of AdipoR1 that is most probably linked to deactivation of the PPAR-alpha/AMP-activated protein kinase pathway. These facts suggest functional adiponectin resistance at the level of the skeletal muscle in CHF.