Adiponectin is an adipocyte-derived secretory protein that has been very widely studied over the past 15 years. A multitude of different functions have been attributed to this adipokine. It has been characterised in vitro at the level of tissue culture systems and in vivo through genetic manipulation of rodent models. It is also widely accepted as a biomarker in clinical studies. Originating in adipose tissue, generally positive metabolic effects have been attributed to adiponectin. In this review, we briefly discuss the key characteristics of this interesting but very complex molecule, highlight recent results in the context of its mechanism of action and summarise some of the key epidemiological data that helped establish adiponectin as a robust biomarker for insulin sensitivity, cardiovascular disease and many additional disease phenomena.
Background Cardiac muscle hypercontractility is a key pathophysiological abnormality in hypertrophic cardiomyopathy, and a major determinant of dynamic left ventricular outflow tract (LVOT) obstruction. Available pharmacological options for hypertrophic cardiomyopathy are inadequate or poorly tolerated and are not disease-specific. We aimed to assess the efficacy and safety of mavacamten, a first-in-class cardiac myosin inhibitor, in symptomatic obstructive hypertrophic cardiomyopathy. Methods In this phase 3, randomised, double-blind, placebo-controlled trial (EXPLORER-HCM) in 68 clinical cardiovascular centres in 13 countries, patients with hypertrophic cardiomyopathy with an LVOT gradient of 50 mm Hg or greater and New York Heart Association (NYHA) class II-III symptoms were assigned (1:1) to receive mavacamten (starting at 5 mg) or placebo for 30 weeks. Visits for assessment of patient status occurred every 2-4 weeks. Serial evaluations included echocardiogram, electrocardiogram, and blood collection for laboratory tests and mavacamten plasma concentration. The primary endpoint was a 1•5 mL/kg per min or greater increase in peak oxygen consumption (pVO 2) and at least one NYHA class reduction or a 3•0 mL/kg per min or greater pVO 2 increase without NYHA class worsening. Secondary endpoints assessed changes in post-exercise LVOT gradient, pVO 2 , NYHA class, Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score (KCCQ-CSS), and Hypertrophic Cardiomyopathy Symptom Questionnaire Shortness-of-Breath subscore (HCMSQ-SoB). This study is registered with ClinicalTrials.gov, NCT03470545.
MARKED INCREASE IN THEprevalence of overweight and obesity 1 has contributed to a doubling in type 2 diabetes mellitus incidence over the past 3 decades. 2 Increasing rates of diabetes among obese individuals has counterbalanced reductions in other cardiovascular disease (CVD) risk factors and is the primary factor contributing to a slowed decline in CVD event rates in the general population. 3 Prediabetes, an intermediate hyperglycemia phenotype and risk factor for diabetes, 4 is also associated with obesity and carries an excess risk for CVD and death. 5 Although increased body mass index (BMI) is associated with diabetes at the population level, 6 it does not adequately discriminate diabetes risk among obese individuals. 7 Indeed, many obese persons appear resistant to the development of metabolic disease. 8 Because the metabolic disease risks associated with obesity are heterogeneous, there remains an unmet clinical need for tools that differentiate obese persons who will ultimately develop prediabetes and diabetes from those who will remain metabolically healthy.Adipose tissue dysfunction is characterized by ectopic fat deposition in the abdominal viscera and liver, inflammatory and adipokine dysregulation, and insulin resistance and may be a more important mediator of diabetes devel-CME available online at www.jamaarchivescme.com and questions on p 1165.
Since the initial description of the phenomenon by Jennings et al 50 years ago, our understanding of the underlying mechanisms of reperfusion injury has grown significantly. Its pathogenesis reflects the confluence of multiple pathways, including ion channels, reactive oxygen species, inflammation, and endothelial dysfunction. This complexity should not deter our efforts to intervene in this process, however, since nearly 2 million patients annually undergo either spontaneous (in the form of acute myocardial infarction) or iatrogenic (in the context of cardioplegic arrest) ischemia-reperfusion. The purpose of this review is to examine our current state of understanding of ischemia-reperfusion injury and highlight recent interventions aimed at this heretofore elusive target. Keywordscoronary artery bypass graft surgery; ischemia; myocardial infarction; reperfusion injury Each year in the United States, there are approximately 1 million myocardial infarctions (MI) and 700,000 patients undergoing cardioplegic arrest for various cardiac surgeries. 1 Minimizing ischemic time in both of these clinical scenarios has appropriately received a great deal of attention owing to the long-established relationship between duration of ischemia and the extent of myocardial injury. Once coronary flow is restored, however, the myocardium is susceptible to another form of insult stemming from reperfusion of the previously ischemic tissue. Given that cardiac ischemia is either unpredictable (MI) or inevitable (in the operating room), there is great interest in developing strategies to minimize reperfusion-mediated injury. Historical perspectiveThe seminal observation that reperfusion following ischemia was associated with myocardial injury was made in 1960 by Jennings and colleagues. 2 Their report was based on experiments with canine hearts subjected to coronary ligation in which reperfusion appeared to accelerate © 2010 Excerpta Medica, Inc. All rights reserved. c Corresponding author: Telephone: (214) Fax: (214) 645-7501, aslan.turer@utsouthwestern.edu, 5323 Harry Hines Blvd, Dallas, TX 75230-9047 . Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Whether reperfusion is independently responsible for tissue injury, or simply hastens the demise of cells otherwise destined for necrosis, remained a matter of debate for some years. Evidence for direct myocardial reperfusion-dependent injury was summarized in 1985 in the classic editorial by Braunwald and Kloner. 3 However, it was not until the discovery of ischemic preconditioning that the independent effects of ischemia and reperfus...
Adverse experiences in childhood and adolescence, defined as subjectively perceived threats to the safety or security of the child's bodily integrity, family, or social structures, are known to be associated with cardiometabolic outcomes over the life course into adulthood. This American Heart Association scientific statement reviews the scientific literature on the influence of childhood adversity on cardiometabolic outcomes that constitute the greatest public health burden in the United States, including obesity, hypertension, type 2 diabetes mellitus, and cardiovascular disease. This statement also conceptually outlines pathways linking adversity to cardiometabolic health, identifies evidence gaps, and provides suggestions for future research to inform practice and policy. We note that, despite a lack of objective agreement on what subjectively qualifies as exposure to childhood adversity and a dearth of prospective studies, substantial evidence documents an association between childhood adversity and cardiometabolic outcomes across the life course. Future studies that focus on mechanisms, resiliency, and vulnerability factors would further strengthen the evidence and provide much-needed information on targets for effective interventions. Given that childhood adversities affect cardiometabolic health and multiple health domains across the life course, interventions that ameliorate these initial upstream exposures may be more appropriate than interventions remediating downstream cardiovascular disease risk factor effects later in life.
Background Reperfusion accounts for a substantial fraction of the myocardial injury occurring with ischemic heart disease. Yet, no standard therapies are available targeting reperfusion injury. Here, we tested the hypothesis that SAHA, a histone deacetylase (HDAC) inhibitor FDA-approved for cancer treatment, will blunt reperfusion injury. Methods and Results Twenty-one rabbits were randomized into 3 groups: a) vehicle control, b) SAHA pretreatment (one day prior and at surgery), and c) SAHA treatment at the time of reperfusion only. Each arm was subjected to ischemia/reperfusion surgery (I/R, 30min coronary ligation, 24h reperfusion). Additionally cultured neonatal and adult rat ventricular cardiomyocytes were subjected to simulated I/R (sI/R) to probe mechanism. SAHA reduced infarct (those reduction inhibitor, SAHA, infarct size in a large animal model, even when delivered in the clinically relevant context of reperfusion. The cardioprotective effects of SAHA during I/R occur, at least in part, through induction of autophagic flux. assayed in both rabbit myocardium and in mice harboring an RFP-GFP-LC3 transgene. In cultured myocytes subjected to sI/R, SAHA pretreatment reduced cell death by 40%. This eduction in cell death correlated with increased autophagic activity in SAHA-treated cells. RNAi-mediated knockdown of ATG7 and ATG5, essential autophagy proteins, abolished SAHA's cardioprotective effects. Conclusions The FDS-approved anti-cancer HDAC inhibitor, SAHA, reduces myocardial infarct size in a large animal model, even when delivered in the clinically relevant context of reperfusion. The cardioprotective effects of SAHA during I/R occur, at least in part, through induction of autophagic flux.
Visceral (VAT) and abdominal subcutaneous (SAT) adipose tissues contribute to obesity but may have different metabolic and atherosclerosis risk profiles. Among obese participants in the Dallas Heart Study, we examined the cross-sectional associations of abdominal VAT and SAT mass, assessed by magnetic resonance imaging (MRI) and indexed to body surface area (BSA), with circulating biomarkers of insulin resistance, dyslipidemia, and inflammation (n=942); and with aortic plaque and liver fat by MRI and coronary calcium by computed tomography (n=1200). Associations of VAT/BSA and SAT/BSA were examined after adjustment for age, sex, race, menopause, and body mass index. In multivariable models, VAT significantly associated with the homeostasis model assessment of insulin resistance (HOMA-IR), lower adiponectin, smaller LDL and HDL particle size, larger VLDL size, and increased LDL and VLDL particle number (p<0.001 for each). VAT also associated with prevalent diabetes, metabolic syndrome, hepatic steatosis, and aortic plaque (p<0.001 for each). VAT independently associated with C-reactive protein but not with any other inflammatory biomarkers tested. In contrast, SAT associated with leptin and inflammatory biomarkers, but not with dyslipidemia or atherosclerosis. Associations between SAT and HOMA-IR were significant in univariable analyses but attenuated after multivariable adjustment. In conclusion, VAT associated with an adverse metabolic, dyslipidemic, and atherogenic obesity phenotype. In contrast, SAT demonstrated a more benign phenotype, characterized by modest associations with inflammatory biomarkers and leptin, but no independent association with dyslipidemia, insulin resistance, or atherosclerosis in obese individuals. These findings suggest that abdominal fat distribution defines distinct obesity sub-phenotypes with heterogeneous metabolic and atherosclerosis risk.
Increased visceral adiposity, but not total or subcutaneous adiposity, was robustly associated with incident hypertension. Additional studies will be needed to elucidate the mechanisms behind this association.
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