Cardiac Adiponectin Research Articles

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.

Effects of Short Term Adiponectin Receptor Agonism on Cardiac Function and Energetics in Diabetic db/db Mice.

ObjectiveImpaired cardiac efficiency is a hallmark of diabetic cardiomyopathy in models of type 2 diabetes. Adiponectin receptor 1 (AdipoR1) deficiency impairs cardiac efficiency in non-diabetic mice, suggesting that hypoadiponectinemia in type 2 diabetes may contribute to impaired cardiac efficiency due to compromised AdipoR1 signaling. Thus, we investigated whether targeting cardiac adiponectin receptors may improve cardiac function and energetics, and attenuate diabetic cardiomyopathy in type 2 diabetic mice.MethodsA non-selective adiponectin receptor agonist, AdipoRon, and vehicle were injected intraperitoneally into Eight-week-old db/db or C57BLKS/J mice for 10 days. Cardiac morphology and function were evaluated by echocardiography and working heart perfusions.ResultsBased on echocardiography, AdipoRon treatment did not alter ejection fraction, left ventricular diameters or left ventricular wall thickness in db/db mice compared to vehicle-treated mice. In isolated working hearts, an impairment in cardiac output and efficiency in db/db mice was not improved by AdipoRon. Mitochondrial respiratory capacity, respiration in the presence of oligomycin, and 4-hydroxynonenal levels were similar among all groups. However, AdipoRon induced a marked shift in the substrate oxidation pattern in db/db mice towards increased reliance on glucose utilization. In parallel, the diabetes-associated increase in serum triglyceride levels in vehicle-treated db/db mice was blunted by AdipoRon treatment, while an increase in myocardial triglycerides in vehicle-treated db/db mice was not altered by AdipoRon treatment.ConclusionAdipoRon treatment shifts myocardial substrate preference towards increased glucose utilization, likely by decreasing fatty acid delivery to the heart, but was not sufficient to improve cardiac output and efficiency in db/db mice.

ALM Fluid Therapy Shifts Sympathetic Hyperactivity to Parasympathetic Dominance in the Rat Model of Non-Compressible Hemorrhagic Shock.

Excessive sympathetic outflow following trauma can lead to cardiac dysfunction, inflammation, coagulopathy, and poor outcomes. We previously reported that buprenorphine analgesia decreased survival after hemorrhagic trauma. Our aim is to examine the underlying mechanisms of mortality in a non-compressible hemorrhage rat model resuscitated with saline or adenosine, lidocaine, magnesium (ALM). Anesthetized adult male Sprague-Dawley rats were randomly assigned to Saline control group or ALM therapy group (both n = 10). Hemorrhage was induced by 50% liver resection. After 15 min, 0.7 mL/kg 3% NaCl ± ALM intravenous bolus was administered, and after 60 min, 0.9% NaCl ± ALM was infused for 4 h (0.5 mL/kg/h) with 72 h monitoring. Animals received 6-12-hourly buprenorphine for analgesia. Hemodynamics, heart rate variability, echocardiography, and adiponectin were measured. Cardiac tissue was analyzed for adrenergic/cholinergic receptor expression, inflammation, and histopathology. Four ALM animals and one Saline control survived to 72 h. Mortality was associated with up to 97% decreases in adrenergic (β-1, α-1A) and cholinergic (M2) receptor expression, cardiac inflammation, myocyte Ca2+ loading, and histopathology, indicating heart ischemia/failure. ALM survivors had higher cardiac output and stroke volume, a 30-fold increase in parasympathetic/sympathetic receptor expression ratio, and higher circulating adiponectin compared to Saline controls. Paradoxically, Saline cardiac adiponectin hormone levels were higher than ALM, with no change in receptor expression, indicating intra-cardiac synthesis. Mortality appears to be a "systems failure" associated with CNS dysregulation of cardiac function. Survival involves an increased parasympathetic dominance to support cardiac pump function with reduced myocardial inflammation. Increased cardiac α-1A adrenergic receptor in ALM survivors may be significant, as this receptor is highly protective during heart dysfunction/failure.

Constant-moderate versus high-intensity interval training on heart adiponectin levels in high-fat fed mice: a preventive and treatment approach

Context Research has described that adiponectin plays a key role in cardiomyocytes metabolism, however, the effects of exercise during obesity on cardiac adiponectin levels is unclear. Objective To investigate the effects of constant-moderate endurance (END) and high-intensity interval training (HIIT), on heart adiponectin levels in mice. Material and methods Two experiments were conducted: (1) preventive (EX1): 10 week-old male mice were fed standard (CHOW) or high-fat diet (HFD;45% fat) and simultaneously trained with END and HIIT for 10 weeks; (2) Treatment (EX2): after 10 weeks of dietary intervention, another cohort of 10 week-old mice were trained by both programmes for 10 weeks. Results In EX1, END and HIIT decreased low-molecular weight adiponectin (∼0.5-fold; p < 0.05) and increased GLUT4 levels (∼2-fold; p < .05). In EX2, HFD significantly decreased high-molecular weight adiponectin (∼0.7-fold; p < .05), and END reversed this change. Discussion and conclusion: HFD and exercise influence heart adiponectin isoforms and therefore might impact cardiomyocyte metabolism.

Adiponectin in onset and progression of T2DM with cardiac dysfunction in rats.

Cardiovascular disease and type 2 diabetes mellitus (T2DM) patients have low level of adiponectin, however, till now the role of adiponectin in progression of 'T2DM with cardiac dysfunction' in animal model has not been characterized. Therefore, the aim of the present study was to develop and characterize T2DM animal model with cardiac dysfunction and to study the role of cardiac adiponectin expression in cardiac dysfunction. For this, Wistar rats (M/F) were fed a high-fat diet for different time periods: 3, 4 and 5 weeks and given a single, low-dose streptozotocin (25mg/kg), intraperitoneal injection 1 week prior to the experiments. Rats in T2DM group (3 weeks) developed hyperglycaemia, hyperlipidaemia, oxidative stress with normoinsulinaemia and mild cardiac dysfunction suggesting onset of T2DM with cardiac dysfunction. Extended high-fat feeding, that is, 4 and 5 weeks induced insulin resistance accompanied with cardiac hypertrophy, cardiac dysfunction and reduced baroreflex sensitivity indicating development of T2DM with cardiac dysfunction. Cardiac adiponectin expression did not change in rats of T2DM group (3 weeks), however, it significantly decreased in rats of two T2DM groups (4 and 5 weeks) along with increased intracellular adhesion molecule-1 levels. Thus, the present study for the first time indicates that in the present T2DM animal model, as T2DM progresses cardiac adiponectin expression also decreases which might be the precipitating factor for cardiac hypertrophy and decrease in baroreflex sensitivity, which induces cardiac dysfunction.

Role of adiponectin in diabetes myocardial ischemia-reperfusion injury and ischemic postconditioning.

Purpose Patients with diabetes are vulnerable to myocardial I/R (ischaemia/reperfusion) injury, but are not responsive to IPO (ischaemic post-conditioning). We hypothesized that decreased cardiac Adiponectin (APN) is responsible for the loss of diabetic heart sensitivity to IPO cardioprotecton.Methods Diabetic rats were subjected to I/R injury (30 min of LAD occlusion followed by 120 min of reperfusion). Myocardial infarct area was determined by TTC staining. Cardiac function was monitored by a microcatheter. ANP, 15-F2t-isoprostane, nitrotyrosine and MDA were measured by assay kits. Levels of p-Akt, total-Akt and GAPDH were determined by Western Blot.Results Diabetic rats subjected to myocardial IR exhibited severe myocardial infarction and oxidative stress injury, lower APN in the plasma and cardiac p-Akt expression ( P <0.05). IPO significantly attenuated myocardial injury and up-regulated plasma APN content and cardiac p-Akt expression in non-diabetic rats but not in diabetic rats. Linear correlation analysis showed that the expression of adiponectin was positively correlated with p-Akt and negatively correlated with myocardial infarction area ( P <0.01).Conclusion Protective effect of IPO was tightly correlated with the expression of adiponectin, exacerbation of I/R injury and ineffectiveness of IPO was partially due to the decline of adiponectin and inactivation of Akt in diabetes mellitus.

Mitochondrial Mechanisms in Diabetic Cardiomyopathy.

Mitochondrial medicine is increasingly discussed as a promising therapeutic approach, given that mitochondrial defects are thought to contribute to many prevalent diseases and their complications. In individuals with diabetes mellitus (DM), defects in mitochondrial structure and function occur in many organs throughout the body, contributing both to the pathogenesis of DM and complications of DM. Diabetic cardiomyopathy (DbCM) is increasingly recognized as an underlying cause of increased heart failure in DM, and several mitochondrial mechanisms have been proposed to contribute to the development of DbCM. Well established mechanisms include myocardial energy depletion due to impaired adenosine triphosphate (ATP) synthesis and mitochondrial uncoupling, and increased mitochondrial oxidative stress. A variety of upstream mechanisms of impaired ATP regeneration and increased mitochondrial reactive oxygen species have been proposed, and recent studies now also suggest alterations in mitochondrial dynamics and autophagy, impaired mitochondrial Ca2+ uptake, decreased cardiac adiponectin action, increased O-GlcNAcylation, and impaired activity of sirtuins to contribute to mitochondrial defects in DbCM, among others. In the current review, we present and discuss the evidence that underlies both established and recently proposed mechanisms that are thought to contribute to mitochondrial dysfunction in DbCM.

Restoration of Adiponectin-Connexin43 Signaling Mitigates Myocardial Inflammation and Dysfunction in Diabetic Female Rats.

ur preclinical findings replicated women's hypersensitivity to type-2 diabetes mellitus (T2DM)-evoked cardiac dysfunction along with demonstrating estrogen (E2)-dependent disruption of the cardiac adiponectin (APN)-connexin43 (Cx43) signaling. Whether the latter molecular anomaly underlies this women's cardiovascular health problem remains unknown. We hypothesized that restoration of the disrupted APN-Cx43 signaling alleviates this sex/E2-dependent cardiac dysfunction in diabetic female rats. To test this hypothesis, we administered the adiponectin receptor 1 (AdipoR1) agonist AdipoRon (30 mg/kg/d for 10 days) to female sham operated (SO) and ovariectomized (OVX) rats, which exhibited and lacked the T2DM left ventricular (LV) dysfunction, respectively, when fed high-fat diet and received low dose streptozotocin regimen; nondiabetic control SO and OVX rats received control diet and vehicle for streptozotocin. In T2DM SO rats, LV dysfunction, AdipoRon mitigated: (1) LV hypertrophy, (2) reductions in fractional shortening, LV developed pressure, dP/dtmax, dP/dtmin, and Tau. In LV tissues of the same rats, AdipoRon reversed reduction in Cx43 and elevations in TNFα, heme-oxygenase 1 (HO-1), and circulating cardiovascular risk factor asymmetric dimethylarginine. The findings also revealed ovarian hormones independent effects of AdipoRon, which included dampening of the pro-oxidant enzyme HO-1. These novel findings yield new insight into a causal role for compromised APN-Cx43 signaling in the E2-dependent hypersensitivity to T2DM-evoked cardiac inflammation and dysfunction. Equally important, the findings identify restoration of Cx43 signaling as a viable therapeutic modality for alleviating this women's cardiovascular health-related problem.

Adiponectin deficiency has no effect in murine autoimmune myocarditis

BackgroundAdiponectin is a hormone that together with its receptors modulates a number of metabolic processes including gluconeogenesis and lipid catabolism. It belongs to the C1QTNF (complement C1q tumor necrosis factor-related protein) family, which has a variety of members with high amino acid sequence homology and overlapping functions. Concentration of adiponectin in blood is inversely correlated with body fat percentage and cardiac risk factors like blood pressure and CRP (C-reactive protein) level. Studies have identified the existence of a cardiac adiponectin system. However, little is known about the role of this system in the pathogenesis of autoimmune myocarditis. Thus, we have studied the involvement of adiponectin in the development of this autoimmune disorder in a mouse model of experimental autoimmune myocarditis (EAM). MethodsAdiponectin knockout (ko) and wild type (wt) mice were immunized with cardiac troponin I (cTnI) to induce an EAM. To determine the severity of myocardial damage, inflammation and fibrosis were scored after HE and Afog staining and high sensitivity troponin T (hsTnT) level was measured. To detect if changes in specific inflammatory cell numbers could be observed between the genotypes, we performed immunohistochemical staining to detect T lymphocytes, B lymphocytes and macrophages. The level of the humoral immune response was determined through the measurement of cTnI-specific serum IgG autoantibodies. Relative mRNA expression of different cytokines, C1QTNF family members and adiponectin receptors in the heart tissue was analyzed with qPCR. ResultsAnimals immunized with cTnI developed autoimmune myocarditis with a significant deterioration of cardiac parameters compared to the corresponding control group. The adiponectin ko group immunized with cTnI showed a tendency towards increased inflammation, fibrosis, heart-to-body-weight ratio, infiltration pattern of T lymphocytes, B lymphocytes and macrophages, hsTnT concentration, humoral immune response and mRNA expression of interleukin 6 in the heart tissue and decreased weight gain compared to the wt group immunized with cTnI. However, the difference to the wt group treated with cTnI was not significant. The analysis of cardiac mRNA expression of adiponectin receptors and four C1QTNF family members, most suitable for fulfilling the functions of adiponectin in adiponectin ko mice, did not show any significant differences between adiponectin ko and wt group at all. ConclusionOur study reveals that the absence of adiponectin did not lead to a significantly increased impairment of cardiac function and was also unlikely to be compensated by its receptors or other C1QTNF family members in the murine model of EAM. Here, other synergistic or redundant effects might play a role and must be investigated in further studies to understand the role and function of adiponectin in autoimmune myocarditis.

PO-183 Effect of Treadmill Running on Brown Adipose Tissue of Heart Failure Rats Induced by Abdominal Aortic Constriction

Objective To observe the effect of treadmill exercise on brown adipose tissue of heart failure rats induced by abdominal aortic constriction(AAC). &#x0D; Methods 210g healthy male SD rats were randomly divided into control group and AAC group，after 4 weeks abdominal aortic constriction rats were selected and randomly divided into AAC group and treadmill running group. The exercise rats underwent treadmill running at 12m/s (40 min each, for 4 weeks). Real-time PCR and immunohistochemistry were used to detect the mRNA content and protein expression of cardiac ANP, BNP, and pgc1-a, ucp-1, leptin and adiponectin of the brown adipose tissue respectively.&#x0D; Results The rats with abdominal aortic constriction developed significant heart failure with preserved LV ejection fraction, increased LVAW d and LVID s. Compared with the control group, the myocardium levels of ANP and BNP in AAC group were significantly up-regulated. In the operation group, the function of brown adipose was enhanced. The volume of brown adipose cells decreased, the number of lipid droplet increased. The mRNA levels of UPC-1 and PGC1-a were significantly up-regulated, and the mRNA levels of leptin and adiponectin were down-regulated. In the exercise group, the browning of brown adipose was reduced, and the mRNA levels of UPC-1 and PGC1-a were decreased.&#x0D; Conclusions Exercise can affect the function of brown adipose tissue in heart failure rats induced by abdominal aortic constriction.

Perinatal ciclosporin A exposure elicits sex-related cardiac dysfunction and inflammation in the rat progeny

Ciclosporin A (CSA) has been identified with harmful cardiotoxicity but little, if any, is known about the influence of perinatal exposure upon the cardiac function of the progeny. The present work examines the premise that perinatal contact with CSA undermines the cardiac function of sexually mature rats. Administration of CSA (15mg/kg/day sc) to pregnant rats from day 6 of conception till weaning led to a decrease in gradient of the end-systolic pressure-volume relationship by a factor of ten for male progeny and a factor of two for female progeny. Perinatally CSA-exposed male, but not female, progeny also demonstrated significantly increased systolic and diastolic blood pressure, along with significantly increased JT interval and a tendency towards increased QTc interval, indicating delayed left ventricular (LV) repolarization and perhaps arrhythmogenesis. Conversely, female, but not male, progeny exposed perinatally to CSA showed a delay in atrioventricular (AV) conduction, as demonstrated by significantly prolonged P duration and a tendency towards increased PR interval. CSA increased serum tumor necrosis factor α (TNFα) and decreased serum adiponectin levels and cardiac adiponectin receptor expression in male progeny, in contrast to no effects in female progeny. Signs of improved oxidative state (decreased 8-isoprostane and increased catalase activity) appeared only in CSA-exposed female rats. Moreover, cardiac muscle degeneration and pyknosis was more observed in male than in female rats. In brief, the sex plays a key role in determining the extent of the deterioration in functional and inflammatory states of the heart that follow perinatal CSA exposure in rats.

Low-intensity endurance exercise plus nandrolone decanoate modulates cardiac adiponectin and its receptors.

Vast adverse effects of anabolic-androgenic steroids (AASs) on athletes' cardiovascular systems have been reported. However, there is still a lack of adequate information regarding the pathways and mechanisms involved. We tested the hypothesis that adiponectin and its receptors in the heart may be affected by long-term use of AASs alongside exercising. Male Wistar rats were randomized into the control (CTL), exercise (EX), nandrolone (Nan), arachis (Arach) group which treated with arachis as vehicle, trained vehicle (EX+Arach) and trained nandrolone (EX+Nan) groups that were treated for 8weeks. One day after the end of the protocol, animals were sacrificed and their hearts were frozen. TNF-α and adiponectin proteins of hearts were evaluated quantitatively by ELISA kits, and Western blot analysis was used for measuring adiponectin receptor protein expression. TNF-α protein increased significantly in the EX+Nan group (P<.05 vs CTL group). The AdipoR1 protein was significantly higher in the presence of nandrolone alongside exercise (P<.05 vs Nan and EX+Arach groups, P<.01 vs CTL and Arach groups). In addition, AdipoR2 protein enhanced in the EX+Nan group when compared with the other groups (P<.05 vs EX and EX+Arach groups, P<.01 vs CTL, Arach and Nan groups). Chronic nandrolone plus mild endurance exercise may be associated with imbalance in pro-/anti-inflammatory cytokines and may induce a positive modulatory effect on cardiac adiporeceptors in rat. Further studies are required before these findings can be generalized to humans.

Regulation of the cardioprotective adiponectin and its receptor AdipoR1 by salt.

Both circulating adiponectin (APN) and cardiac APN exert cardioprotective effects and improve insulin sensitivity and mitochondrial function. Low circulating APN serves as a biomarker for cardiovascular risk. Ablation of adiponectin receptor 1 (AdipoR1) causes myocardial mitochondrial dysfunction. Although high salt intake is a contributor to cardiovascular disease, how it modulates the expression of APN or AdipoR1 in cardiomyocytes is not known. We report that APN mRNA expression was attenuated in a dose-dependent manner in mouse cardiomyocyte cell line HL-1 exposed to salt concentrations ranging from 0.75% to 1.5% for 12 h. High-salt exposure (0.88% and 1.25% for 12 h) also suppressed APN and AdipoR1 protein expression significantly in rat cardiac muscle H9c2 cells. Co-immunostaining for AdipoR1 and mitochondrial complex 1 indicated that AdipoR1 may be co-localized with mitochondria. These data show for the first time that high salt is an important suppressor of cardiovascular protective APN and AdipoR1.

Abstract P173: Caloric Restriction Attenuates Diabetic Cardiomyopathy Through the Recruitment of the Antioxidant System

Introduction: Insulin resistance negatively impacts the diabetic heart in various ways, that include impaired insulin-mediated glucose uptake and a reduction in intracellular signalling. Diabetic cardiomyopathy is independent of coronary artery disease and is characterized by increased oxidative stress and extensive fibrotic changes, leading to increased myocardial stiffness and the development of diastolic dysfunction. Caloric restriction (CR) is cardioprotective mainly through its catabolic activity and increased insulin sensitivity. We examined the effect of CR on the development of diabetic cardiomyopathy and changes in oxidative stress and antioxidant genes. Methods: Leptin resistant (db/db) mice suffer from obesity and diabetes. Mice were treated for 4 weeks with angiotensin II (AT) to induce severe cardiomyopathy. Mice under CR were fed 90% of their normal food intake for 2 weeks and 65% for an additional 2 weeks. Each group consisted of 5-6 animals. Results: CR attenuated obesity and the cardiomyopathy phenotype in diabetic mice. CR reduced body weight and heart weight in diabetic mice when compared to control animals (33.7±7.9g vs.44 ±5.9g; 0.137±0.023g vs. 0.17±0.02g respectively, p&lt;0.05); and lowered blood glucose (576±167mg/dL vs 702.5±309 mg/dL, p&lt;0.05). Echocardiography indicated that CR attenuated the hypertrophic phenotype in the diabetic mice when compared to control animals (LV internal diameter 3.34±0.46mm vs. 4.06±0.36mm, p&lt;0.01). Diabetic mice treated with AT suffer from oxidative stress as evident in a 110% increase in serum MDA levels (p&lt;0.011), a reduction of 81% in adiponectin (p&lt;0.001) and 65% in PGC-1α (p&lt;0.0046) mRNA levels in cardiac tissue of diabetic mice compared to WT mice. The attenuation of diabetic cardiomyopathy after CR was accompanied by a reduction in serum MDA levels (p&lt;0.028) and an increase in cardiac adiponectin, HO-1 and PGC-1α levels (p&lt;0.05). Conclusion: These results indicate that a short term CR attenuated the development of AT induced diabetic cardiomyopathy through the activation of the adiponectin- PGC-1α- HO-1-axis. This appears to be a critical module in protecting the diabetic heart from the development of cardiomyopathy.

Swimming training attenuates the morphological reorganization of the myocardium and local inflammation in the left ventricle of growing rats with untreated experimental diabetes

Diabetic cardiomyopathy is associated with cardiac remodeling, myocardial dysfunction, low-grade inflammation, and reduced cardiac adiponectin in patients with type 1 diabetes mellitus (T1DM). Alternatively, physical exercise is an important strategy for the management of diabetes. This study aimed to investigate the influence of low-intensity swimming training in cardiac cytokines, structural remodeling, and cardiomyocyte contractile dysfunction in growing rats with untreated experimental DM. Thirty-day-old male Wistar rats were divided into four groups (n=14, per group): sedentary control (SC), exercised control (EC), sedentary diabetic (SD), and exercised diabetic (ED). Diabetes was induced by streptozotocin (60mgkg−1, i.p.). Animals from exercised groups swam (5 days/week, 90min/day, loading up to 5% body weight around the animal's chest) for 8 weeks. The left ventricle (LV) was removed for molecular, morphological, and cardiomyocyte mechanical analysis. Diabetic animals presented cardiac remodeling with myocardial histoarchitectural disorganization, fibrosis, and necrosis. The capillary density was lower in diabetic animals. LV cardiomyocytes from diabetic animals exhibited more prolonged time to the peak of contraction and time to half relaxation than those from control animals. The cardiac levels of interleukin 10, nitric oxide, and total and high molecular weight (HMW) adiponectin were significantly decreased in diabetic animals. Exercise training reduced the level of TNF-α, increased capillary density, and attenuated the histopathological parameters assessed in diabetic rats. In conclusion, the cardiac structural remodeling coexists with reduced levels of total and HMW adiponectin, inflammation, and cardiomyocyte contractility dysfunction in experimental DM. More important, low-intensity swimming training attenuates part of these pathological changes, indicating the beneficial role for exercise in untreated T1DM.

Effect of intensive statin therapy on coronary intervention outcomes, cardiac markers, vaspin, and adiponectin levels in elderly patients with coronary heart disease

Aim: To explore the effect of intensive statin therapy (different doses) on percutaneous coronary intervention (PCI) outcomes in elderly patients with coronary heart disease (CHD). Methods: In this Institutional Ethics Committee-approved study, 105 elderly patients (> 80-year-old) with CHD admitted into the First Affiliated Hospital of Jinan University from June 2012 to June 2014 were randomly divided into three groups and received 20 mg/day, 40 mg/day, or 60 mg/day atorvastatin, respectively, before PCI surgery. Postsurgical (1 month after surgery) changes in major adverse cardiovascular events (MACEs), cardiac markers, vaspin, and adiponectin levels were compared among the groups. Results: Among the study groups, the incidence of MACE and PCI-related myocardial infarction rate was the lowest in 60 mg group (2.9%) reaching significance ( P P P P P > 0.05). No study subjects showed statin-related myopathy. Conclusion: The application of 60 mg/d intensive statin therapy in short term could improve outcomes of PCI in patients with elderly CHD, maintain stable levels of cardiac markers, Vaspin and adiponectin, with exact effect and good safety.

Abstract 19715: Diabetes Abrogates the Cardioprotective Effects of Ischemic Postconditioning Cardioprotection by Impairing AdipoR1/Caveolin-3/STAT3 Signaling

Introduction: Ischemic postconditioning (IPo) protects against myocardial ischemia reperfusion (MI/R) injury by activating mitochondrial signal transducer and activator of transcription 3 (mitoSTAT3) through adiponectin (APN) in non-diabetes, but losses its effectiveness in diabetes whose cardiac APN is reduced. We postulated that malfunction of APN is the key mechanism whereby IPo losses cardioprotection in diabetes. Methods and Results: Four-week (4w) or eight-week (8w) streptozotocin-induced diabetic rats were treated with APN adenovirus (tail vein injection, 1*109 pfu) 1-week before inducing MI/R (30 minutes of left coronary artery ligation followed by 2 hours of reperfusion) with or without IPo (3 cycles of 10s of ischemia and 10s of reperfusion, n=6 per group). At the end of reperfusion, myocardial injury was more severe in both 4w and 8w diabetic rats evidenced as increased infarct size than age-matched control (43.4±3.3 in 4w diabetic vs. 30.6±2.2 in control, 55.4±2.0 in 8w diabetic vs. 38.0±1.9 in control, all P&lt;0.05) concomitant with increased plasma CK-MB release and worse cardiac function (lower dP/dtmax and ejection fraction), and more severely impaired mitochondrial function (decrease in complex I, II+III, and IV activities), more severe reduction of activated mitoSTAT3 and colocolization of APN receptor-1(AdipoR1) and caveolin-3(Cav3), a molecule essential for APN signaling. These changes cannot be reversed by IPo alone in both 4w and 8w diabetic rats, while IPo in combination with APN significantly attenuated all the abovementioned changes in 4w diabetic but not in 8w diabetic rats whose baseline and post-ischemic cardiac AdipoR1 and Cav3 expression were more severely reduced than that in 4 w diabetic rats. The protective effects of joint IPo and APN treatment in 4w diabetes were abolished by inhibition of STAT3 irrespectiove of IPo and APN induced enhancement of AdipoR1 and Cav3 expression and colocalization. Conclusion: IPo loses cardioprotection in diabetes due to reduced APN and impaired AdipoR1/Cav3 signaling. APN supplementation by activating mitoSTAT3 restores IPo cardioprotection in 4w diabetic where AdipoR1 and Cav3 are functionally interactive, but not in 8w diabetic rats whose AdipoR1/Cav3 signaling impaired.

Abstract 108: C1q-TNF Related Protein-9, a Novel Cardioprotective Cardiokine, Requires Proteolytic Cleavage to Generate a Biologically Active Globular Domain Isoform

The discovery of the cardiac secretomes, known as “cardiokines”, significantly enhanced appreciation of the local microenvironment’s influence upon disease development. We previously reported cardiomyocytes produce cardioprotective adiponectin (APN). However, cardiac APN levels are several orders of magnitude below adipocytes, thereby making APN an unlikely physiologically relevant cardiokine. C1qTNF-related proteins (CTRP1-15) is a newly descovered family of APN paralogs. However, whether any of the CTRP members may function as a “true” cardiokine remains unknown. Here we demonstrated that several CTRPs (CTRP1,4,7,9,13) were expressed in the heart at levels significantly greater than APN. Most notably, the mRNA level of CTRP9 exceeded APN by &gt;100-fold in cardiac tissue. Adult cardiac cells were isolated and cultured in vitro. Conditioned medium was collected 1-8 hours after culture and CTRP9 protein levels were determined by ELISA. A significant increase of CTRP9 in conditioned medium was detected as early as 1 hour in culture, steadily accumulating thereafter. These results indicate CTRP9 is secreted by cardiac cell at levels that may function as a cardiokine. Addional experiemnt unexpectedly demonstarted that CTRP9 circulates in the plasma primarily in the globular domain isoform (gCTRP9), opposing from APN which circulates as full length multimers. Recombinant full length CTRP9 (fCTRP9) was cleaved when incubated with cardiac tissue extracts, generating gCTRP9, a process inhibited by protease inhibitor cocktail. To gain more insight into the biological significance of gCTRP9 production, isolated adult cardiomyocytes were treated with gCTRP9 or fCTRP9. gCTRP9 rapidly activates cardiac survival kinases, including AMPK, Akt, and eNOS. However, fCTRP9-mediated kinase activation is much less potent, and significantly delayed. Kinase activation by fCTRP9, but not gCTRP9, is inhibited by protease inhibitor cocktail. These results demonstrate for the first time CTRP9 is a novel cardiokine undergoing proteolytic cleavage to generate cardioprotective isoform, gCTRP9. Enhancing cardiac CTRP9 production and/or its proteolytic post-translational modification are of therapeutic potential, attenuating cardiac injury.

Acute adiponectin delivery is cardioprotective in the aged female rat heart.

The aged, post-menopausal female heart is characterized by reduced ischemic tolerance, and few therapies currently exist to limit ischemic damage. Adiponectin (APN), a cytokine produced in adipose tissue, limits infarct size and improves functional recovery after ischemia/reperfusion injury in adult hearts. The aim of the present study was to extend these previous studies and determine the cardioprotective efficacy of APN treatment in aged female rats. Hearts were isolated from adult (age 6-7 months; n = 10), aged (age 23 months; n = 14) and aged ovariectomized (n = 10) female rats, and subjected to ischemia/reperfusion injury. On ischemia, hearts were infused with 9 μg of APN or vehicle. Adiponectin receptor 1, adiponectin receptor 2 and adenosine monophosphate-dependent kinase (AMPK) were assessed by western blotting, tumor necrosis factor-α and nicotinamide adenine dinucleotide phosphate oxidase levels by real time polymerase chain reaction. Non-reducing western blotting for APN multimers in visceral adipose was also carried out. APN infusion successfully improved post-ischemic left ventricular developed pressure (∼10-15%) and attenuated the rise in end diastolic pressure in all groups (P < 0.05). With ischemia/reperfusion injury, phospho-AMPK increased in all groups with additive effects of APN on increasing phospho-AMPK abundance in aged ovary-intact female rats only (P < 0.001). Age-associated increases in pre-ischemic tumor necrosis factor-α mRNA were unaffected by APN, whereas nicotinamide adenine dinucleotide phosphate oxidase 2 mRNA levels were attenuated by APN in adult and aged ovariectomized female rats. An age-associated decrease in cardiac adiponectin receptor 2 was observed in conjunction with elevated high molecular weight APN in adipose. The present data suggest that APN might be a relevant therapy for protecting the aging female heart, albeit through divergent mechanisms that are likely influenced by age-associated estrogen availability.

Adiponectin expression and the cardioprotective role of the vitamin D receptor activator paricalcitol and the angiotensin converting enzyme inhibitor enalapril in ApoE-deficient mice.

Coronary heart disease (CHD) is the number one cause of death in the US. The adipokine adiponectin has been studied intensively for presenting and inversed association with almost every stage of CHD. For instance, the evaluation of molecules capable of enhancing endogenous adiponectin expression is well justified. In this study, we investigated the effect of the vitamin D receptor activator (VDRA) paricalcitol and the angiotensin-converting enzyme inhibitor (ACEI) enalapril on adiponectin expression, lipid profiles, adenosine monophosphate activated protein kinase (AMPK) expression, monocyte chemo-attractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNFα),cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), antioxidant capacity, CuZn-superoxide dismutase (CuZn-SOD), Mn-SOD, NADPH p22phox subunits, inducible nitric oxidesynthase (iNOS), endothelial marker eNOS, and 81 atherosclerosis-related genes in ApoE-deficient mice. Seven-week-old ApoE-deficient mice were treated for 16 weeks as follows: Group 1, ApoE vehicle control (intraperitoneal [i.p.] 100 µl propylene glycol); Group 2, ApoE-paricalcitol (200 ng i.p., 3/week); Group 3, ApoE-Enalapril (30 mg/kg daily); Group 4, ApoE-paricalcitol + enalapril (described dosing); and Group 5, wild-type control (C57BLV). All treated groups presented significant changes in circulating and cardiac adiponectin, cardiac cholesterol levels, AMPK, MCP-1, TNF-α, COX-2, iNOS, eNOS, CuZn-SOD, Mn-SOD and p22phox. There were 15 genes that differed in their expression, 5 of which are involved in cardioprotection and antithrombotic mechanisms: Bcl2a1a, Col3a1, Spp1 (upregulated), Itga2, and Vwf (downregulated). Together, our data presented a novel role for VDRA and ACEI in reducing factors associated with CHD that may lead to the discovery of new therapeutic venues.