Phase I studies of the safety, tolerability, pharmacokinetics, and pharmacodynamics of DS-1211, a tissue-nonspecific alkaline phosphatase inhibitor.

Tissue-nonspecific alkaline phosphatase (TNAP) hydrolyzes and inactivates inorganic pyrophosphate (PPi), a potent inhibitor of calcification; therefore, TNAP inhibition is a potential target to treat ectopic calcification. These two first-in-human studies evaluated safety, tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of single (SAD) and multiple-ascending doses (MAD) of DS-1211, a TNAP inhibitor. Healthy adults were randomized 6:2 to DS-1211 or placebo, eight subjects per dose cohort. SAD study subjects received one dose of DS-1211 (range, 3-3000 mg) or placebo, whereas MAD study subjects received DS-1211 (range, 10-300 mg) once daily, 150 mg twice daily (b.i.d.), or placebo for 10 days. Primary end points were safety and tolerability. PK and PD assessments included plasma concentrations of DS-1211, alkaline phosphatase (ALP) activity, and TNAP substrates (PPi, pyridoxal 5'-phosphate [PLP], and phosphoethanolamine [PEA]). A total of 56 (DS-1211: n = 42; placebo: n = 14) and 40 (DS-1211: n = 30; placebo: n = 10) subjects enrolled in the SAD and MAD studies, respectively. In both studies, adverse events were mild or moderate and did not increase with dose. PKs of DS-1211 were linear up to 100 mg administered as a single dose and 150 mg b.i.d. administered as a multiple-dose regimen. In multiple dosing, there was minimal accumulation of DS-1211. Increased DS-1211 exposure correlated with dose-dependent ALP inhibition and concomitant increases in PPi, PLP, and PEA. In two phase I studies, DS-1211 appeared safe and well-tolerated. Post-treatment PD assessments were consistent with exposure-dependent TNAP inhibition. These data support further evaluation of DS-1211 for ectopic calcification diseases.

NaPi-IIb Inhibition for Hyperphosphatemia in CKD Hemodialysis Patients.

INTRODUCTION: Chronic kidney disease (CKD) has a prevalence of 9.1% globally, and frequently results in elevated serum phosphate, increasing cardiovascular morbidity and mortality risk in hemodialysis (HD) patients. DS-2330b, an oral NaPi-IIb inhibitor, reduced intestinal phosphate absorption in preclinical studies, but its effect in patients with CKD is unknown. This 2-part, randomized, placebo- and active-controlled, single- and repeated-dose, phase 1b study evaluated safety and efficacy of DS-2330b in patients with CKD on HD. METHODS: Part A, a 2-period, 2-way study, evaluated safety and pharmacokinetics of DS-2330b 250 mg in solution and tablet formulations. Part B assessed the safety of DS-2330b in solution (chosen based on results of part A) and its effect on serum phosphate. Patients were randomized to placebo 3 times daily (TID), DS-2330b 400 mg TID, DS-2330b 400 mg with sevelamer 1.6 g TID, and sevelamer 1.6 g with placebo TID for 14 days. Safety endpoints included adverse event (AE) monitoring. RESULTS: Six patients completed part A. Two patients experienced serious AEs considered unrelated to DS-2330b treatment. Thirty-two patients enrolled and completed part B. Serum phosphate mean change from baseline ± SD was -2.2±1.5 mg/dl versus -1.9 ± 1.1 mg/dl for DS-2330b monotherapy versus placebo. Patients receiving DS-2330b with sevelamer or sevelamer with placebo experienced the greatest serum phosphate decrease from baseline. Nine patients (28.1%) experienced ≥1 treatment-emergent AE (TEAE); 7 patients experienced drug-related TEAEs. The TEAE incidence was comparable between DS-2330b and control groups. CONCLUSIONS: DS-2330b, alone or in combination with sevelamer, was safe and well tolerated but did not demonstrate clinically meaningful efficacy in HD patients.

Myonectin Is an Exercise-Induced Myokine That Protects the Heart From Ischemia-Reperfusion Injury.

RATIONALE: Physical exercise provides benefits for various organ systems, and some of systemic effects of exercise are mediated through modulation of muscle-derived secreted factors, also known as myokines. Myonectin/C1q (complement component 1q)/TNF (tumor necrosis factor)-related protein 15/erythroferrone is a myokine that is upregulated in skeletal muscle and blood by exercise. OBJECTIVE: We investigated the role of myonectin in myocardial ischemic injury. METHODS AND RESULTS: Ischemia-reperfusion in myonectin-knockout mice led to enhancement of myocardial infarct size, cardiac dysfunction, apoptosis, and proinflammatory gene expression compared with wild-type mice. Conversely, transgenic overexpression of myonectin in skeletal muscle reduced myocardial damage after ischemia-reperfusion. Treadmill exercise increased circulating myonectin levels in wild-type mice, and it reduced infarct size after ischemia-reperfusion in wild-type mice, but not in myonectin-knockout mice. Treatment of cultured cardiomyocytes with myonectin protein attenuated hypoxia/reoxygenation-induced apoptosis via S1P (sphingosine-1-phosphate)-dependent activation of cAMP/Akt cascades. Similarly, myonectin suppressed inflammatory response to lipopolysaccharide in cultured macrophages through the S1P/cAMP/Akt-dependent signaling pathway. Moreover, blockade of S1P-dependent pathway reversed myonectin-mediated reduction of myocardial infarct size in mice after ischemia-reperfusion. CONCLUSIONS: These data indicate that myonectin functions as an endurance exercise-induced myokine which ameliorates acute myocardial ischemic injury by suppressing apoptosis and inflammation in the heart, suggesting that myonectin mediates some of the beneficial actions of exercise on cardiovascular health.

Relaxin Family Member Insulin-Like Peptide 6 Ameliorates Cardiac Fibrosis and Prevents Cardiac Remodeling in Murine Heart Failure Models.

BACKGROUND: The insulin/insulin-like growth factor/relaxin family represents a group of structurally related but functionally diverse proteins. The family member relaxin-2 has been evaluated in clinical trials for its efficacy in the treatment of acute heart failure. In this study, we assessed the role of insulin-like peptide 6 (INSL6), another member of this protein family, in murine heart failure models using genetic loss-of-function and protein delivery methods. METHODS AND RESULTS: Insl6-deficient and wild-type (C57BL/6N) mice were administered angiotensin II or isoproterenol via continuous infusion with an osmotic pump or via intraperitoneal injection once a day, respectively, for 2 weeks. In both models, Insl6-knockout mice exhibited greater cardiac systolic dysfunction and left ventricular dilatation. Cardiac dysfunction in the Insl6-knockout mice was associated with more extensive cardiac fibrosis and greater expression of fibrosis-associated genes. The continuous infusion of chemically synthesized INSL6 significantly attenuated left ventricular systolic dysfunction and cardiac fibrosis induced by isoproterenol infusion. Gene expression profiling suggests liver X receptor/retinoid X receptor signaling is activated in the isoproterenol-challenged hearts treated with INSL6 protein. CONCLUSIONS: Endogenous Insl6 protein inhibits cardiac systolic dysfunction and cardiac fibrosis in angiotensin II- and isoproterenol-induced cardiac stress models. The administration of recombinant INSL6 protein could have utility for the treatment of heart failure and cardiac fibrosis.

Acute and Chronic Increases of Circulating FSTL1 Normalize Energy Substrate Metabolism in Pacing-Induced Heart Failure.

BACKGROUND: FSTL1 (follistatin-like protein 1) is an emerging cardiokine/myokine that is upregulated in heart failure (HF) and is found to be cardioprotective in animal models of cardiac injury. We tested the hypothesis that circulating FSTL1 can affect cardiac function and metabolism under baseline physiological conditions and in HF. METHODS AND RESULTS: FSTL1 was acutely (10 minutes) or chronically (2 weeks) infused to attain clinically relevant blood levels in conscious dogs with cardiac tachypacing-induced HF. Dogs with no cardiac pacing and FSTL1 infusion served as control. 3H-oleate and 14C-glucose were infused to track the metabolic fate of free fatty acids and glucose. Cardiac uptake of lactate and ketone bodies and systemic respiratory quotient were also measured. HF caused a shift from prevalent cardiac and systemic fat to carbohydrate oxidation. Although acute FSTL1 administration caused minimal hemodynamic changes at baseline, in HF dogs it enhanced cardiac oxygen consumption and transiently reversed the changes in free fatty acid and glucose oxidation and systemic respiratory quotient. In HF, chronic FSTL1 infusion stably normalized cardiac free fatty acid, glucose, ketone body consumption, and systemic respiratory quotient, while moderately improving diastolic and contractile function. Consistently, FSTL1 prevented the downregulation of medium-chain acyl-CoA dehydrogenase-a representative enzyme of the free fatty acid oxidation pathway. Complementary in vitro experiments in primary cardiac and skeletal muscle myocytes showed that FSTL1 stimulated oxygen consumption through AMPK (AMP-activated kinase) activation. CONCLUSIONS: These findings support a novel function for FSTL1 and provide the first direct evidence that a circulating cardiokine/myokine can alter myocardial and systemic energy substrate metabolism, in vivo.

Higher efficacy of direct hemoperfusion using coated activated-charcoal column for disopyramide poisoning: A case report.

RATIONALE: Cases of severe disopyramide poisoning are rare and few have been reported. We report a case in which activated-charcoal column hemoperfusion was dramatically effective for life-threatening disopyramide poisoning. PATIENT CONCERNS: A teenage girl who had overdosed on disopyramide (total dose, 4950 mg) was brought to our hospital. She was resuscitated from short period cardiopulmonary arrest and subsequently showed severe cardiogenic shock and ventricular arrhythmia. DIAGNOSES: Disopyramide poisoning (self-evident). INTERVENTIONS: As hemodynamics remained unstable after providing percutaneous cardiopulmonary support and intra-aortic balloon pumping, we attempted direct hemoperfusion using a coated activated-charcoal hemoperfusion column. OUTCOMES: Hemodynamics including electrocardiography and serum disopyramide concentration were dramatically improved, and the patient was ambulatory by hospital day 14. LESSONS: Because disopyramide has low molecular weight and a small distribution volume, blood purification is considered to be the most effective therapy. We selected direct hemoperfusion for relatively high protein-binding rate. In fact, clinical status was dramatically improved, and the calculated half-life of the direct hemoperfusion phase was the shortest of all phases. In cases of severe or life-threatening disopyramide poisoning, blood purification therapy including direct hemoperfusion using a coated activated-charcoal column should be performed.

Enormous Pedunculated Vegetation Originating in the Left Ventricular Apex in a Patient with Infective Endocarditis.

A healthy teenage Japanese girl was admitted to our hospital after experiencing out-of-hospital cardiac arrest. She had attempted to commit suicide by taking 4,950 mg of disopyramide and 12 mg of flunitrazepam. Mechanical cardiopulmonary support was started with percutaneous cannulation of the femoral vessels. Several days later, a blood culture tested positive for Staphylococcus aureus. Transthoracic echocardiography showed a large mobile and solid mass attached to the apical part of the left ventricle. To the best of our knowledge, the anatomical location of a pedunculated mass originating from the apex is a rare condition.

Follistatin-like 1 promotes cardiac fibroblast activation and protects the heart from rupture.

Follistatin-like 1 (Fstl1) is a secreted protein that is acutely induced in heart following myocardial infarction (MI). In this study, we investigated cell type-specific regulation of Fstl1 and its function in a murine model of MI Fstl1 was robustly expressed in fibroblasts and myofibroblasts in the infarcted area compared to cardiac myocytes. The conditional ablation of Fstl1 in S100a4-expressing fibroblast lineage cells (Fstl1-cfKO mice) led to a reduction in injury-induced Fstl1 expression and increased mortality due to cardiac rupture during the acute phase. Cardiac rupture was associated with a diminished number of myofibroblasts and decreased expression of extracellular matrix proteins. The infarcts of Fstl1-cfKO mice displayed weaker birefringence, indicative of thin and loosely packed collagen. Mechanistically, the migratory and proliferative capabilities of cardiac fibroblasts were attenuated by endogenous Fstl1 ablation. The activation of cardiac fibroblasts by Fstl1 was mediated by ERK1/2 but not Smad2/3 signaling. This study reveals that Fstl1 is essential for the acute repair of the infarcted myocardium and that stimulation of early fibroblast activation is a novel function of Fstl1.

miR-410 and miR-495 Are Dynamically Regulated in Diverse Cardiomyopathies and Their Inhibition Attenuates Pathological Hypertrophy.

Noncoding RNAs have emerged as important modulators in cardiac development and pathological remodeling. Recently, we demonstrated that regulation of the Gtl2-Dio3 noncoding RNA locus is dependent on the MEF2 transcription factor in cardiac muscle, and that two of its encoded miRNAs, miR-410 and miR-495, induce robust cardiomyocyte proliferation. Given the possibility of manipulating the expression of these miRNAs to repair the damaged heart by stimulating cardiomyocyte proliferation, it is important to determine whether the Gtl2-Dio3 noncoding RNAs are regulated in cardiac disease and whether they function downstream of pathological cardiac stress signaling. Therefore, we examined expression of the above miRNAs processed from the Gtl2-Dio3 locus in various cardiomyopathies. These noncoding RNAs were upregulated in all cardiac disease models examined including myocardial infarction (MI) and chronic angiotensin II (Ang II) stimulation, and in the cardiomyopathies associated with muscular dystrophies. Consistent with these observations, we show that the Gtl2-Dio3 proximal promoter is activated by stress stimuli in cardiomyocytes and requires MEF2 for its induction. Furthermore, inhibiting miR-410 or miR-495 in stressed cardiomyocytes attenuated the hypertrophic response. Thus, the Gtl2-Dio3 noncoding RNA locus is a novel marker of cardiac disease and modulating the activity of its encoded miRNAs may mitigate pathological cardiac remodeling in these diseases.

Epicardial FSTL1 reconstitution regenerates the adult mammalian heart.

The elucidation of factors that activate the regeneration of the adult mammalian heart is of major scientific and therapeutic importance. Here we found that epicardial cells contain a potent cardiogenic activity identified as follistatin-like 1 (Fstl1). Epicardial Fstl1 declines following myocardial infarction and is replaced by myocardial expression. Myocardial Fstl1 does not promote regeneration, either basally or upon transgenic overexpression. Application of the human Fstl1 protein (FSTL1) via an epicardial patch stimulates cell cycle entry and division of pre-existing cardiomyocytes, improving cardiac function and survival in mouse and swine models of myocardial infarction. The data suggest that the loss of epicardial FSTL1 is a maladaptive response to injury, and that its restoration would be an effective way to reverse myocardial death and remodelling following myocardial infarction in humans.

The injury-induced myokine insulin-like 6 is protective in experimental autoimmune myositis.

BACKGROUND: The idiopathic inflammatory myopathies represent a group of autoimmune diseases that are characterized by lymphocyte infiltration of muscle and muscle weakness. Insulin-like 6 (Insl6) is a poorly characterized member of the insulin-like/relaxin family of secreted proteins, whose expression is upregulated upon acute muscle injury. METHODS: In this study, we employed Insl6 gain or loss of function mice to investigate the role of Insl6 in a T cell-mediated model of experimental autoimmune myositis (EAM). EAM models in rodents have involved immunization with human myosin-binding protein C with complete Freund's adjuvant (CFA) emulsions and pertussis toxin. RESULTS: Insl6-deficiency in mice led to a worsened myositis phenotype including increased infiltration of CD4 and CD8 T cells and the elevated expression of inflammatory cytokines. Insl6-deficient mice show significant motor function impairment when tested with treadmill or Rotarod devices. Conversely, muscle-specific overexpression of Insl6 protected against the development of myositis as indicated by reduced lymphocyte infiltration in muscle, diminished inflammatory cytokine expression and improved motor function. The improvement in myositis by Insl6 could also be demonstrated by acute hydrodynamic delivery of a plasmid encoding murine Insl6. In cultured cells, Insl6 inhibits Jurkat cell proliferation and activation in response to phytohemagglutinin/phorbol 12-myristate 13-acetate stimulation. Insl6 transcript expression in muscle was reduced in a cohort of dermatomyositis and polymyositis patients. CONCLUSIONS: These data suggest that Insl6 may have utility for the treatment of myositis, a condition for which few treatment options exist.

Vascular rarefaction mediates whitening of brown fat in obesity.

Brown adipose tissue (BAT) is a highly vascularized organ with abundant mitochondria that produce heat through uncoupled respiration. Obesity is associated with a reduction of BAT function; however, it is unknown how obesity promotes dysfunctional BAT. Here, using a murine model of diet-induced obesity, we determined that obesity causes capillary rarefaction and functional hypoxia in BAT, leading to a BAT "whitening" phenotype that is characterized by mitochondrial dysfunction, lipid droplet accumulation, and decreased expression of Vegfa. Targeted deletion of Vegfa in adipose tissue of nonobese mice resulted in BAT whitening, supporting a role for decreased vascularity in obesity-associated BAT. Conversely, introduction of VEGF-A specifically into BAT of obese mice restored vascularity, ameliorated brown adipocyte dysfunction, and improved insulin sensitivity. The capillary rarefaction in BAT that was brought about by obesity or Vegfa ablation diminished ß-adrenergic signaling, increased mitochondrial ROS production, and promoted mitophagy. These data indicate that overnutrition leads to the development of a hypoxic state in BAT, causing it to whiten through mitochondrial dysfunction and loss. Furthermore, these results link obesity-associated BAT whitening to impaired systemic glucose metabolism.

Therapeutic impact of follistatin-like 1 on myocardial ischemic injury in preclinical models.

BACKGROUND: Acute coronary syndrome is a leading cause of death in developed countries. Follistatin-like 1 (FSTL1) is a myocyte-derived secreted protein that is upregulated in the heart in response to ischemic insult. Here, we investigated the therapeutic impact of FSTL1 on acute cardiac injury in small and large preclinical animal models of ischemia/reperfusion and dissected its molecular mechanism. METHODS AND RESULTS: Administration of human FSTL1 protein significantly attenuated myocardial infarct size in a mouse or pig model of ischemia/reperfusion, which was associated with a reduction of apoptosis and inflammatory responses in the ischemic heart. Administration of FSTL1 enhanced the phosphorylation of AMP-activated protein kinase in the ischemia/reperfusion-injured heart. In cultured cardiac myocytes, FSTL1 suppressed apoptosis in response to hypoxia/reoxygenation and lipopolysaccharide-stimulated expression of proinflammatory genes through its ability to activate AMP-activated protein kinase. Ischemia/reperfusion led to enhancement of bone morphogenetic protein-4 expression and Smad1/5/8 phosphorylation in the heart, and FSTL1 suppressed the increased phosphorylation of Smad1/5/8 in ischemic myocardium. Treating cardiac myocytes with FSTL1 abolished the bone morphogenetic protein-4-stimulated increase in apoptosis, Smad1/5/8 phosphorylation, and proinflammatory gene expression. In cultured macrophages, FSTL1 diminished lipopolysaccharide-stimulated expression of proinflammatory genes via activation of AMP-activated protein kinase and abolished bone morphogenetic protein-4-dependent induction of proinflammatory mediators. CONCLUSIONS: Our data indicate that FSTL1 can prevent myocardial ischemia/reperfusion injury by inhibiting apoptosis and inflammatory response through modulation of AMP-activated protein kinase- and bone morphogenetic protein-4-dependent mechanisms, suggesting that FSTL1 could represent a novel therapeutic target for post-myocardial infarction, acute coronary syndrome.

CTRP9 protein protects against myocardial injury following ischemia-reperfusion through AMP-activated protein kinase (AMPK)-dependent mechanism.

Ischemic heart disease is the major cause of death in Western countries. CTRP9 (C1q/TNF-related protein 9) is a fat-derived plasma protein that has salutary effects on glucose metabolism and vascular function. However, the functional role of CTRP9 in ischemic heart disease has not been clarified. Here, we examined the regulation of CTRP9 in response to acute cardiac injury and investigated whether CTRP9 modulates cardiac damage after ischemia and reperfusion. Myocardial ischemia-reperfusion injury resulted in reduced plasma CTRP9 levels and increased plasma free fatty acid levels, which were accompanied by a decrease in CTRP9 expression and an increase in NADPH oxidase component expression in fat tissue. Treatment of cultured adipocytes with palmitic acid or hydrogen peroxide reduced CTRP9 expression. Systemic administration of CTRP9 to wild-type mice, before the induction of ischemia or at the time of reperfusion, led to a reduction in myocardial infarct size following ischemia-reperfusion. Administration of CTRP9 also attenuated myocyte apoptosis in ischemic heart, which was accompanied by increased phosphorylation of AMP-activated protein kinase (AMPK). Treatment of cardiac myocytes with CTRP9 protein reduced apoptosis in response to hypoxia/reoxygenation and stimulated AMPK phosphorylation. Blockade of AMPK activity reversed the suppressive actions of CTRP9 on cardiomyocyte apoptosis. Knockdown of adiponectin receptor 1 diminished CTRP9-induced increases in AMPK phosphorylation and survival of cardiac myocytes. Our data suggest that CTRP9 protects against acute cardiac injury following ischemia-reperfusion via an AMPK-dependent mechanism.

Transbrachial intra-aortic balloon pumping for a patient with fulminant myocarditis.

A 57-year-old man with acute myocarditis was transferred to our hospital from a local clinic. The patient experienced unexpected sudden cardiac arrest 16 h after admission. Mechanical cardiopulmonary support was started using percutaneous cardiopulmonary support, intra-aortic balloon pumping (IABP), continuous hemodialysis filtration, and temporary cardiac pacing with percutaneous cannulation of the femoral vessels. Hematoma developed at the IABP insertion site on the 5th day after admission. The IABP was removed, and another IABP system was inserted via the left brachial artery. The patient's condition improved, and the IABP was removed on the 9th day after admission. The remainder of the patient's in-hospital treatment was uneventful, and he showed near-normal left ventricular systolic function 1 year after discharge.

Fat-derived factor omentin stimulates endothelial cell function and ischemia-induced revascularization via endothelial nitric oxide synthase-dependent mechanism.

Obesity-related diseases are associated with vascular dysfunction and impaired revascularization. Omentin is a fat-derived secreted protein, which is down-regulated in association with obese complications. Here, we investigated whether omentin modulates endothelial cell function and revascularization processes in vitro and in vivo. Systemic delivery of an adenoviral vector expressing omentin (Ad-omentin) enhanced blood flow recovery and capillary density in ischemic limbs of wild-type mice in vivo, which were accompanied by increased phosphorylation of Akt and endothelial nitric oxide synthase (eNOS). In cultured human umbilical vein endothelial cells (HUVECs), a physiological concentration of recombinant omentin protein increased differentiation into vascular-like structures and decreased apoptotic activity under conditions of serum starvation. Treatment with omentin protein stimulated the phosphorylation of Akt and eNOS in HUVECs. Inhibition of Akt signaling by treatment with dominant-negative Akt or LY294002 blocked the stimulatory effects of omentin on differentiation and survival of HUVECs and reversed omentin-stimulated eNOS phosphorylation. Pretreatment with the NOS inhibitor also reduced the omentin-induced increase in HUVEC differentiation and survival. Omentin protein also stimulated the phosphorylation of AMP-activated protein kinase in HUVECs. Transduction with dominant-negative AMP-activated protein kinase diminished omentin-induced phosphorylation of Akt and omentin-stimulated increase in HUVEC differentiation and survival. Of importance, in contrast to wild-type mice, systemic administration of Ad-omentin did not affect blood flow in ischemic muscle in eNOS-deficient mice in vivo. These data indicate that omentin promotes endothelial cell function and revascularization in response to ischemia through its ability to stimulate an Akt-eNOS signaling pathway.

Heart fatty acid-binding protein offers similar diagnostic performance to high-sensitivity troponin T in emergency room patients presenting with chest pain.

BACKGROUND: The aim of the present study was to evaluate the diagnostic accuracy of high-sensitivity troponin T (hsTnT) in patients with suspected acute coronary syndrome (ACS) in comparison to heart fatty acid-binding protein (H-FABP), high-sensitivity C-reactive protein, myeloperoxidase (MPO), and pentraxin 3 (PTX3). METHODS AND RESULTS: Patients (n=432) with chest pain were recruited for the analysis. ACS was diagnosed in 298 patients (69%). The diagnostic accuracy of measurements obtained at presentation, as quantified by the area under the receiver operating curve (AUC), was highest for hsTnT (AUC=0.82; 95% confidence interval [CI]: 0.78-0.87) and H-FABP (AUC=0.83; 95%CI: 0.78-0.87). Sensitivity (87.9%) and negative likelihood (LH; 0.2) for hsTnT were the highest and lowest, respectively, but H-FABP had the highest specificity (78.5%) and positive LH (3.6). Among patients who presented within 2h after the onset of chest pain, MPO had the highest AUC (0.82; 95%CI: 0.69-0.94). Combined use of H-FABP and MPO measurements yielded a sensitivity of 69.2%, specificity of 84.2%, positive LH of 4.4, and negative LH of 0.4. CONCLUSIONS: The hsTnT assay offers excellent diagnostic performance to rule out ACS, but it is prone to false-positive results. H-FABP offers similar overall diagnostic performance, while the combination of H-FABP and MPO assays may improve the diagnosis of ACS, particularly in patients with recent onset of chest pain.

Adipolin/C1qdc2/CTRP12 protein functions as an adipokine that improves glucose metabolism.

Obesity is a major risk factor for the development of insulin resistance and type 2 diabetes. Adipose tissue secretes various bioactive molecules, referred to as adipokines, whose dysregulation can mediate changes in glucose homeostasis and inflammatory responses. Here, we identify C1qdc2/CTRP12 as an insulin-sensitizing adipokine that is abundantly expressed by fat tissues and designate this adipokine as adipolin (adipose-derived insulin-sensitizing factor). Adipolin expression in adipose tissue and plasma was reduced in rodent models of obesity. Adipolin expression was also decreased in cultured 3T3-L1 adipocytes by treatment with inducers of endoplasmic reticulum stress and inflammation. Systemic administration of adipolin ameliorated glucose intolerance and insulin resistance in diet-induced obese mice. Adipolin administration also reduced macrophage accumulation and proinflammatory gene expression in the adipose tissue of obese mice. Conditioned medium from adipolin-expressing cells diminished the expression of proinflammatory cytokines in response to stimulation with LPS or TNFα in cultured macrophages. These data suggest that adipolin functions as an anti-inflammatory adipokine that exerts beneficial actions on glucose metabolism. Therefore, adipolin represents a new target molecule for the treatment of insulin resistance and diabetes.

Adiponectin ameliorates doxorubicin-induced cardiotoxicity through Akt protein-dependent mechanism.

Accumulating evidence shows that obesity is associated with doxorubicin cardiac toxicity in the heart, but the molecular mechanisms that contribute to this pathological response are not understood. Adiponectin is an adipose-derived, cardioprotective factor that is down-regulated in obesity. Here, we investigated the effect of adiponectin on doxorubicin (DOX)-induced cardiotoxicity and assessed the mechanisms of this effect. A single dose of DOX was intraperitoneally injected into the abdomen of adiponectin knock-out (APN-KO) and wild-type (WT) mice. APN-KO mice had increased mortality and exacerbated contractile dysfunction of left ventricle compared with WT mice. APN-KO mice also showed increased apoptotic activity and diminished Akt signaling in the failing myocardium. Systemic delivery of adenoviral vector expressing adiponectin improved left ventricle dysfunction and myocardial apoptosis following DOX injection in WT and APN-KO mice but not in Akt1 heterozygous KO mice. In cultured rat neonatal cardiomyocytes, adiponectin stimulated Akt phosphorylation and inhibited DOX-stimulated apoptosis. Treatment with sphingosine kinase-1 inhibitor or sphingosine 1-phosphate receptor antagonist diminished adiponectin-induced Akt phosphorylation and reversed the inhibitory effects of adiponectin on myocyte apoptosis. Pretreatment with anti-calreticulin antibody reduced the binding of adiponectin to cardiac myocytes and blocked the adiponectin-stimulated increase in Akt activation and survival in cardiomyocytes. Interference of the LRP1/calreticulin co-receptor system by siRNA or blocking antibodies diminished the stimulatory actions of adiponectin on Akt activation and myocyte survival. These data show that adiponectin protects against DOX-induced cardiotoxicity by its ability to promote Akt signaling.

Fenofibrate promotes ischemia-induced revascularization through the adiponectin-dependent pathway.

Recent clinical trials demonstrated that PPARα agonist fenofibrate reduces cardiovascular events, including limb amputation in people with type 2 diabetes. Here, we investigated whether fenofibrate modulates the revascularization process in a mouse model of hindlimb ischemia. Treatment with fenofibrate led to acceleration of revascularization of ischemic hindlimb relative to the contralatereal limb in wild-type (WT) mice, as measured by laser Doppler blood flow and capillary density analyses. Treatment of WT mice with fenofibrate increased the serum levels of adiponectin, which has protective actions on the vasculature. Of importance, fenofibrate had no effects on the revascularization in ischemic limbs of adiponectin-deficient (APN-KO) mice. Fenofibrate stimulated the phosphorylation of AMPK and eNOS in the ischemic muscles in WT mice but not in APN-KO mice. AMPK inhibitor compound C suppressed fenofibrate-induced increase in limb perfusion and AMPK phosphorylation in ischemic muscle in WT mice without affecting adiponectin levels. NOS inhibitor l-NAME also blocked the increased blood flow of ischemic limbs in fenofibrate-treated WT mice. Our observations suggest that fenofibrate could promote revascularization in response to ischemia through adiponectin-dependent AMPK signaling.