Adiponectin, T-cadherin and tumour necrosis factor-alpha in damaged cardiomyocytes from autopsy specimens

Ghrelin and adipokines: An overview of their physiological role, antimicrobial activity and impact on cardiovascular conditions

The human body has many different hormones that interact with each other and with other factors such as proteins, cell receptors and metabolites. There is still a limited understanding of some of the underlying biological mechanisms of some hormones. In the past decades, science and technology have made major advancements in regard to innovation and knowledge in fields such as medicine. However, some conditions are complex and have many variables that their full picture is still unclear, even though some of these conditions have an alarming rate of incidence and serious health consequences. Conditions such as type 2 diabetes, obesity, nonalcoholic liver disease (NAFLD), cancer in its different forms and even mental conditions, such as Alzheimer's disease, are some of the most common diseases in the 21st century. These conditions are relevant not only because of their high incidence on the general population, but also because of their severity. In this chapter, we present an overview of cardiovascular (CV) diseases. According to the World Health Organization (WHO), cardiovascular diseases, such as coronary artery disease (CAD), heart attack, cardiomyopathy and heart failure (among others), are the number one cause of death worldwide. In 2016, it was estimated that 17.9 million people died from CV diseases, representing more than 30% of all global deaths. Approximately 95% of people who died from CV diseases were so-called "premature deaths" because were referenced to individuals under the age of 70 years old. In this chapter we described some of the hormones that may have an impact on CV diseases, including ghrelin, a peptide that is mostly produced in the stomach, known to induce hunger. Ghrelin is linked to an increase in body fat, i.e., adipose tissue in animals. For this reason, we also included the adipokines leptin, adiponectin and resistin. The main objectives of this chapter are to present the state of the art knowledge concerning the mechanisms of each hormone relevant to CV diseases; to compile data and results that further elucidate the relevance of these peptides for several physiological events, conditions and diseases; and to discuss the metabolic impact of each hormone. We established connections between multiple peptides and the underlying condition/disease with tools such as STRING, referring to research using databases, such as UniProt, DisGeNET and Proteomics DB. Fig. 1 shows a network that summarizes the information presented in this chapter, which serves as a visual representation.

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.

Adiponectin and Its Receptors Are Differentially Expressed in Human Tissues and Cell Lines of Distinct Origin

BACKGROUND

Adiponectin is secreted by adipose tissue and exerts high abundance and an anti-inflammatory potential. However, only little information exists about the expression profiles of adiponectin and its recently identified receptor CDH13 in non-tumorous human tissues and their association to clinical parameters.

METHODS

The expression levels of adiponectin and CDH13 were analyzed in heart, liver, kidney, spleen, skin, blood vessels, peripheral nerve and bone marrow of 21 human body donors, in 12 human cell lines, and in purified immune effector cell populations of healthy blood donors by immunohistochemistry, Western-blot, and semi-quantitative PCR. The obtained results were then correlated to clinical parameters, including age, sex and known diseases like cardiovascular and renal diseases.

RESULTS

Adiponectin expression in renal corpuscles was significantly higher in humans with known renal diseases. A coordinated expression of adiponectin and CDH13 was observed in the myocard. High levels of adiponectin could be detected in the bone marrow, in certain lymphoid tumor cell lines and in purified immune effector cell populations of healthy donors, in particular in cytotoxic T cells.

CONCLUSION

For the first time, the expression profiles of adiponectin and CDH13 are analyzed in many human tissues in correlation to each other and to clinical parameters.

Antagonistic effects of selenium against necroptosis injury via adiponectin-necrotic pathway induced by cadmium in heart of chicken

Cadmium (Cd) is one of the most toxic heavy metals having a destructive impact on various organ systems.

Endothelin-1-Induced Cell Hypertrophy in Cardiomyocytes is Improved by Fenofibrate: Possible Roles of Adiponectin

Aim: Previous studies demonstrated that endothelin-1 (ET-1) can significantly increase the cell size and stimulate adiponectin expression in cultured human cardiomyocytes (HCM). The aim of the present study was to investigate the effects of fenofibrate, a peroxisome proliferator-activated receptor-α (PPARα) activator, on cell hypertrophy and adiponectin expression in vitro and in a rat model of daunorubicin-induced cardiomyopathy.

Methods: The cultured human cardiomyocytes (HCM) were stimulated with or without ET-1. The cell size and the protein expressions of PPARα and adiponectin were tested by confocal Immunofluorescence study and Western blot, respectively. To study the effects of PPARα activation on ET-1-induced cell hypertrophy and adiponectin protein synthesis, HCM were pretreated with fenofibrate or small interfering RNA (siRNA) of PPARα. Echocardiographic parameters were measured and immunohistochemistry study of myocardial adiponectin expression was conducted in the in vivo study.

Results: ET-1 significantly increased the cell size, dose-dependently suppressed the expression of PPARα, and enhanced the expression of adiponectin; whereas, such an increase of cell size and enhancement of adiponectin expression were inhibited by the pre-treatment with fenofibrate. Addition of siRNA of PPARα abolished the effects of fenofibrate. Moreover, we found that fenofibrate treatment can significantly improve the left ventricular function and reverse the myocardial expression of adiponectin.

Conclusions: Our study shows that fenofibrate may protect against ET-1-induced cardiomyocyte hypertrophy and enhanced adiponectin expression through modulation of PPARα expression in vitro and limitation of daunorubicin cardiotoxicity in vivo, suggesting a novel mechanistic insight into the role of PPARα and adiponectin in cardiac hypertrophy and heart failure.

T-cadherin association with clinicopathological features and prognosis in axillary lymph node-positive breast cancer

The purpose of this study was to investigate the correlation of T-cadherin expression with clinicopathological features and prognosis in patients with axillary lymph node-positive breast cancer. Based on the immunohistochemistry results, all 142 patients with operable axillary lymph node-positive breast cancer were divided into the T-cadherin-negative and T-cadherin-positive groups. Clinical data including the association of T-cadherin expression with clinicopathological features and prognosis were analyzed using the Chi square test and Fisher's exact test using SPSS 13.0 software. The impact of T-cadherin expression on the 5-year disease-free survival (DFS) and the 5-year overall survival (OS) of these patients was measured using the log-rank test. DFS and OS were analyzed using both Kaplan-Meier function and Cox regression analyses. Compared with the T-cadherin-positive group (55.07, 28.99, and 13.4 %, respectively; P = 0.030, P = 0.0132, and P = 0.009), tumor size >2 cm, lymph-vascular invasion, and pathological stage III disease were seen more frequently in the T-cadherin-negative group (72.60, 49.32, and 31.51 %, respectively). Both 5-year DFS and 5-year OS were poorer in the T-cadherin-negative group than in the T-cadherin-positive group (log-rank test = 9.295, P = 0.002; log-rank test = 5.718, P = 0.017). On multivariate analysis, T-cadherin-negative expression remained an independent prognostic factor for DFS (P = 0.002) but not for OS (P = 0.067). Our results suggested that negative T-cadherin expression has a worse prognosis in patients with axillary lymph node-positive breast cancer.

Role of adipokines in cardiovascular disease

The discovery of leptin in 1994 sparked dramatic new interest in the study of white adipose tissue. It is now recognised to be a metabolically active endocrine organ, producing important chemical messengers - adipokines and cytokines (adipocytokines). The search for new adipocytokines or adipokines gained added fervour with the prospect of the reconciliation between cardiovascular diseases (CVDs), obesity and metabolic syndrome. The role these new chemical messengers play in inflammation, satiety, metabolism and cardiac function has paved the way for new research and theories examining the effects they have on (in this case) CVD. Adipokines are involved in a 'good-bad', yin-yang homoeostatic balance whereby there are substantial benefits: cardioprotection, promoting endothelial function, angiogenesis and reducing hypertension, atherosclerosis and inflammation. The flip side may show contrasting, detrimental effects in aggravating these cardiac parameters.

Telmisartan attenuates isoproterenol-induced cardiac remodeling in rats via regulation of cardiac adiponectin expression

AIM

To investigate whether telmisartan (Telm) pretreatment attenuates isoproterenol (Iso)-induced postinfarction remodeling (PIR) in rats, and whether the effect of Telm is associated with cardiac expression of adiponectin.

METHODS

PIR was induced in male Wistar rats with two consecutive injections of Iso (80 mg/kg, sc) at an interval of 24 h. Primary culture of ventricular myocytes from neonatal rats was prepared. Iso-induced cardiomyocyte injury was assessed based on cell growth and lactate dehydrogenase (LDH) activity. Cardiac adiponectin expression was measured using qRT-PCR and immunoblot analysis.

RESULTS

In the rats with PIR, Telm (10 mg·kg(-1)·d(-1), po for 65 d) suppressed Iso-induced increases in gravimetric parameters, cardiomyocyte diameter and collagen volume fraction, but had no effect on Iso-induced myocardial hypertrophy and interstitial fibrosis. The protective effect of Telm was associated with enhanced protein expression of cardiac adiponectin. In cultured cardiomyocytes, Telm (5-20 μmol/L) inhibited the cell death and LDH release induced by Iso (10 μmol/L), and reversed Iso-induced reduction in adiponectin protein expression. In cardiomyocytes exposed to Iso (20 μmol/L), GW9662 (30 μmol/L), a selective antagonist of PPAR-γ, blocked the effects of Telm pretreatment on adiponectin protein expression, as well as the protective effects of Telm on Iso-induced cell injury.

CONCLUSION

Telm attenuates Iso-induced cardiac remodeling and cell injury, which is associated with induction of cardiac adiponectin expression.

The effects of a PPARalpha agonist on myocardial damage in obese diabetic mice with heart failure

Recent studies have confirmed that PPARalpha agonists have not brought the anticipated benefits to patients with type 2 diabetes and potentially fatal heart disease. We hypothesized that such agonists may have a cardio-suppressive effect in treating such disorders, therefore, we inoculated diabetic KKAy mice with encephalomyocarditis virus (EMCv) to induce a diabetic model with severe myocardial damage. WY14643, a potent PPARalpha agonist, was administered intraperitoneally either simultaneously (WY14643-late group) or 3 days before viral inoculation (WY14643-early group). WY14643-treated mice, especially those in the WY14643-early group, had higher mortality than those in the vehicle-treated group (vehicle) in the first 5 days after EMCv inoculation. However, the survival rate in the vehicle group decreased rapidly after day 4 and was the lowest of all 3 groups by day 9. The WY14643-treated mice showed reduced body weight and blood glucose, improved myocardial pathological changes, lower cardiac TNF-alpha expression, and significantly higher adiponectin expression, whereas the LW/LC ratio was lower and cardiac UCP3 mRNA expression higher in the WY14643 treatment groups than in the vehicle group on day 4. WY14643 therefore has cardioprotective and cardio-suppressive effects when used to treat EMCv-induced myocarditis in diabetic mice. The cardioprotective effect may be due to its anti-inflammatory properties and its ability to increase cardiac adiponectin expression, whereas the reduced cardiac efficiency may be due to its enhancement of cardiac UCP3 mRNA expression.

The cannabinoid CB1 receptor antagonist, rimonabant, protects against acute myocardial infarction

CB1 antagonism is associated with reduced doxorubicin-induced cardiotoxicity and decreased cerebrocortical infarction. Rimonabant, a selective CB1 receptor antagonist, was, before it was withdrawn, proposed as a treatment for obesity and reported to reduce cardiovascular risk by improving glucose and lipid profiles and raising adiponectin levels. The cardioprotective actions of rimonabant in 6-week-old C57BL/6J mice fed either high-fat (HFD) or standard diets (STD) for 8 weeks were investigated. At 14 weeks, mice received rimonabant (10 mg/kg/day, i.p.) or vehicle for 1 week and were then subjected to an in vivo acute myocardial infarction. The influence of rimonabant on infarct size (IS) in CB1 knockout (CB1-/-) and wild-type (CB1+/+) mice was also examined. C57BL/6J mice that had been maintained on STD or HFD exhibited 4.3 and 21.4% reductions in body weight following 7 days rimonabant treatment. Rimonabant reduced IS in both STD (29.6 +/- 3.5% vs. 49.8 +/- 6.9% in control, P < 0.05) and HFD (26.9 +/- 1.5% vs. 48.7 +/- 7% in control, P < 0.05) mice. In CB1-/- mice rimonabant failed to reduce body weight or IS (51.0 +/- 5.3% vs. 49.7 +/- 4.7% in control, P > 0.05), although significant reductions were seen in CB1+/+ mice (IS, 48.9 +/- 4.6% control vs. 30.5 +/- 3.1% rimonabant, P < 0.05). To exclude the possibility that weight loss alone induced cardioprotection, HFD mice were switched to STD for 7 days (HFD-STD), resulting in an 11.3 +/- 1.0% decrease in body weight compared to control (+2.1 +/- 1.1% in HFD). This, however, was not associated with IS reduction (39.1 +/- 3.9% HFD-STD vs. 40.0 +/- 5.3% HFD, P > 0.05). Serum and cardiac adiponectin levels were unaltered by rimonabant treatment. HL-1 cell death was not prevented by 1 or 7 days treatment with rimonabant. We conclude that rimonabant-induced infarct limitation may involve the CB1 receptor, although not necessarily cardiac CB1 receptors, and is unrelated to weight loss or altered adiponectin synthesis.

Cardiac remodeling in obesity

The dramatic increase in the prevalence of obesity and its strong association with cardiovascular disease have resulted in unprecedented interest in understanding the effects of obesity on the cardiovascular system. A consistent, but puzzling clinical observation is that obesity confers an increased susceptibility to the development of cardiac disease, while at the same time affording protection against subsequent mortality (termed the obesity paradox). In this review we focus on evidence available from human and animal model studies and summarize the ways in which obesity can influence structure and function of the heart. We also review current hypotheses regarding mechanisms linking obesity and various aspects of cardiac remodeling. There is currently great interest in the role of adipokines, factors secreted from adipose tissue, and their role in the numerous cardiovascular complications of obesity. Here we focus on the role of leptin and the emerging promise of adiponectin as a cardioprotective agent. The challenge of understanding the association between obesity and heart failure is complicated by the multifaceted interplay between various hemodynamic, metabolic, and other physiological factors that ultimately impact the myocardium. Furthermore, the end result of obesity-associated changes in the myocardial structure and function may vary at distinct stages in the progression of remodeling, may depend on the individual pathophysiology of heart failure, and may even remain undetected for decades before clinical manifestation. Here we summarize our current knowledge of this complex yet intriguing topic.

Candesartan improves myocardial damage in obese mice with viral myocarditis and induces cardiac adiponectin

PURPOSE

To clarify the mechanism of the effects of angiotensin II receptor type 1 antagonist, candesartan, upon cardiac adiponectin in the combination of myocarditis with obesity, we examined obese KKAy mice with acute viral myocarditis treated by candesartan and investigated cardiac adiponectin regulation.

METHODS

Mice were divided into candesartan early treatment group (Can-early) receiving orally candesartan at daily dose of 10 mg/kg 7 days starting before viral inoculation and then 7 days; candesartan late treatment group (Can-late) or vehicle (Vehicle) receiving candesartan starting simultaneously with viral inoculation and then 7 days. Encephalomyocarditis virus was used to induce the acute viral myocarditis. Differences in myocardial damages, serum adiponectin and myocardial expression of adiponectin, tumor necrosis factor-alpha (TNF-alpha), CCAAT/enhancer binding proteinalpha (C/EBPalpha) and peroxisome proliferator-activated receptor gamma (PPAR-gamma) and nuclear factor-kappaB (NF-kappaB) mRNA among three groups were determined on days 0, 4 and 7 after viral inoculation.

RESULTS

Mice in Can-early and Can-late groups showed reduced myocardial necrosis and cellular infiltration as compared with those in the Vehicle. On day 4 the circulating adiponectin levels were significantly higher in Can-early than those in Vehicle. Mice in Vehicle had significantly reduced in myocardial adiponectin mRNA after viral myocarditis. Cardiac adiponectin mRNA was significantly higher in Can-early and in Can-late than in Vehicle on days 4 and 7. Cardiac C/EBPalpha in Can-early and Can-early groups was significantly increased on day 4. Myocardial NF-kappaB and TNF-alpha mRNA in Can-early and Can-late groups were significantly reduced on day 7.

CONCLUSION

Candesartan treatment improved myocardial injury in obese mice with acute viral myocarditis and induced expression of cardiac adiponectin with the induction of C/EBPalpha as well as the reduction of cardiac NF-kappaB and TNF-alpha.

Oral administration of candesartan improves the survival of mice with viral myocarditis through modification of cardiac adiponectin expression

PURPOSE

We examined the effects of the angiotensin II receptor type 1 blocker candesartan on myocarditis injury in a murine model of acute myocarditis. We hypothesized that candesartan improves cardiac damage by inducing cardiac expression of adiponectin.

METHODS AND RESULTS

We examined changes in heart failure caused by myocarditis in mice by candesartan based on induction of cardiac adiponectin expression. We intraperitoneally injected encephalomyocarditis virus in C3H mice, then orally administered candesartan (10 mg/kg/day) or vehicle (control). The 7 day survival rate was 18% in the control group, but 60% in the candesartan group. The heart weight/body weight ratio in the candesartan group was significantly lower than in the control group. Circulating adiponectin concentrations on day 7 were significantly higher in the candesartan group compared with the control group (7.91 +/- 0.61 vs. 6.04 +/- 2.26 microg/ml, P < 0.05). Comparative expression of cardiac adiponectin mRNA in the candesartan group was significantly higher than in the control group on day 7 (55.4 +/- 41.3 vs. 5.3 +/- 7.7, P < 0.05). Immunohistochemical staining and in situ hybridization showed that cardiac expression of adiponectin protein and mRNA was present in the candesartan group on day 7.

CONCLUSION

Oral administration of candesartan improves survival and decreases myocardial damage in mice with viral myocarditis and induces expression of cardiac adiponectin. The induction of adiponectin might provide cardioprotective effects against acute heart failure due to viral myocarditis.

Adiponectin and the cardiovascular system: from risk to disease

Adiponectin is known to play a role in fatty acid and glucose metabolism through a change in insulin sensitivity and activation of fuel oxidation by AMP-activated protein kinase. Adiponectin can be considered an important factor able to modulate the adipovascular axis which, through genomic and environmental influences, affects the cardiovascular risk milieu, from the pre-metabolic syndrome-- through the metabolic syndrome--to the overt atherosclerotic process and its clinical manifestations. Hypoadiponectinaemia can be viewed as an early sign of a complex cardiovascular risk factor predisposing to the atherosclerosis process as well as a contributing factor accelerating the progress of the atherosclerotic plaque. In addition, adiponectin per se holds a protective role thanks to its anti-inflammatory and antiatherogenic properties. The early identification of patients "at cardiovascular risk" means in the current practice to search for indexes of metabolic derangements and pro-inflammatory status (adiponectin) from adolescence and childhood.

Q. Adiponectin and its receptors are expressed in adult ventricular cardiomyocytes and upregulated by activation of peroxisome proliferator-activated receptor gamma

Adiponectin is a protein hormone involved in maintaining energy homeostasis in metabolically active tissues. It enhances glucose and lipid metabolism via activation of AMP-dependent kinase (AMPK) in skeletal muscle and liver. Energy homeostasis is vital for the heart to work as a pump. In this study, we investigated whether adiponectin and its receptors are expressed in adult ventricular cardiomyocytes. We observed adiponectin transcript and protein in cultured ventricular cardiomyocytes isolated from adult rat, by quantitative real-time PCR, ELISA assays, Western blots, and immunofluorescent staining. In addition, we detected adiponectin receptor (AdipoR1 and AdipoR2) expression in the heart. AdipoR1 was expressed in rat myocardium at a level of approximately 50% of that in skeletal muscle; whereas adipoR2 was expressed at a similar level to that in liver. Rosiglitazone, a Peroxisome proliferator activated receptor gamma (PPARgamma) activator, substantially elevated expression of adiponectin in cultured cardiomyocytes and its secretion into cultured media. Rosiglitazone also increased adipoR1 and adipoR2 expression in cardiomyocytes. Treatment of recombinant globular adiponectin in cultured cardiomyocytes increased fatty acid oxidation and glucose uptake via activation of AMPK, suggesting a role for adiponectin in cardiac energy metabolism. Together, these data establish the existence of a local cardiac-specific adiponectin system that is regulated by PPARgamma. Moreover, these findings indicate a role for adiponectin on normal myocardial energy homeostasis, in part, through the activation of AMPK.

Targeting adiponectin for cardioprotection

Adiponectin is an adipose tissue-derived plasma protein which has a reduced concentration in subjects with obesity-related diseases. Adiponectin has antidiabetic and anti-inflammatory characteristics, which lead to beneficial actions on various obesity-linked complications. Recent experimental findings have shown that adiponectin contributes to protection against cardiac remodelling after pressure overload and cardiac injury following ischaemia-reperfusion. Thus, adiponectin could emerge as a potential cardioprotective agent for the treatment of several pathological heart conditions.

Reduced-energy diet improves survival of obese KKAy mice with viral myocarditis: induction of cardiac adiponectin expression

Obesity is an important risk factor for heart disease. Whether weight loss affects the severity of heart failure induced by viral myocarditis is a matter of debate. We hypothesized that weight loss could improve cardiac dysfunction by inducing cardiac expression of a cardioprotective cytokine, adiponectin. We examined the relationship between weight loss by food restriction and heart failure due to viral myocarditis in obese KKAy mice. We intraperitoneally injected encephalomyocarditis virus (500 plaque-forming units/mouse) into KKAy mice fed ad libitum as a control (CF) or 60% restriction of that eaten by ad libitum (RF). The 14-day survival rate was 0% in FF, whereas it was 23% in RF (P<0.01). Heart weight/body weight ratio in RF was lower than that in FF on day 5 after viral inoculation (P<0.05). Histological scores for myocardial necrosis and inflammation on day 5 were significantly lower in RF than in FF (P<0.05). Circulating adiponectin level on day 0 was significantly elevated in RF compared with that in FF (32+9 vs. 22+2 microg/mL, P<0.05). Comparative expression of cardiac adiponectin mRNA in RF was significantly higher than that in FF (5.1+0.3 vs. 1+0.2, P<0.05). Cardiac tumor necrosis factor-alpha (TNF-alpha) mRNA in RF was significantly decreased compared with that in FF on day 5 (P<0.05). Cardiac expression of nuclear factor kappa B was reduced and that of peroxisome proliferator-activated receptor gamma mRNA was increased in RF in comparison with FF on day 0. Cardiac adiponectin mRNA was negatively correlated with cardiac TNF-alpha mRNA (r=-0.555; P=0.0097). Weight loss improved the survival and myocardial damage in obese mice with viral myocarditis, with cardiac induction of adiponectin. The induction of adiponectin might provide benefit through a cardioprotective effect against acute heart failure due to viral myocarditis in obese subjects.

Cardioprotection by adiponectin

Obesity-related disorders are closely associated with the pathogenesis of cardiovascular disease. Adiponectin is a circulating adipose tissue-derived hormone that is down-regulated in obese individuals. Hypoadiponectinemia has been identified as an independent risk factor for type 2 diabetes, coronary artery disease, and hypertension, and experimental studies show that adiponectin plays a protective role in the development of insulin resistance, atherosclerosis, and inflammation. More recent findings have shown that adiponectin directly affects signaling in myocardial cells and exerts beneficial actions on the heart after pressure overload and ischemia-reperfusion injury. This review focuses on the role of adiponectin in the regulation of myocardial remodeling and acute cardiac injury.

Adiponectin actions in the cardiovascular system

Obesity is strongly associated with the pathogenesis of type 2 diabetes, hypertension, and cardiovascular disease. Levels of the hormone adiponectin are downregulated in obese individuals, and several experimental studies show that adiponectin protects against the development of various obesity-related metabolic and cardiovascular diseases. Adiponectin exhibits favorable effects on atherogenesis, endothelial function, and vascular remodeling by modulation of signaling cascades in cells of the vasculature. More recent findings have shown that adiponectin directly affects signaling in cardiac cells and is beneficial in the setting of pathological cardiac remodeling and acute cardiac injury. Several of these effects of adiponectin have been attributed to the activation of the 5' AMP-activated protein kinase signaling cascade and other signaling proteins. This review will discuss the epidemiological and experimental studies that have elucidated the role of adiponectin in a variety of cardiovascular diseases.