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Cardioprotective Role of Myeloid-Derived Suppressor Cells in Heart Failure [Original Research Article]

Circulation - Lun, 09/07/2018 - 19:44
Background:Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells that expand in cancer, inflammation, and infection and negatively regulate inflammation and the immune response. Heart failure (HF) is a complex clinical syndrome wherein inflammation induction and incomplete resolution can potentially contribute to HF development and progression. However, the role of MDSCs in HF remains unclear.Methods:The percentage of MDSCs in patients with HF and in mice with pressure overload–induced HF using isoproterenol infusion or transverse aortic constriction (TAC) was detected by flow cytometry. The effects of MDSCs on isoproterenol- or TAC-induced HF were observed on depleting MDSCs with 5-fluorouracil (50 mg/kg) or gemcitabine (120 mg/kg), transferring purified MDSCs, or enhancing endogenous MDSCs with rapamycin (2 mg·kg?1·d?1). Hypertrophic markers and inflammatory factors were detected by ELISA, real-time polymerase chain reaction, or Western blot. Cardiac functions were determined by echocardiography and hemodynamic analysis.Results:The percentage of human leukocyte antigen-D–related (HLA-DR)?CD33+CD11b+ MDSCs in the blood of patients with HF was significantly increased and positively correlated with disease severity and increased plasma levels of cytokines, including interleukin-6, interleukin-10, and transforming growth factor–?. Furthermore, MDSCs derived from patients with HF inhibited T-cell proliferation and interferon-? secretion. Similar results were observed in TAC- and isoproterenol-induced HF in mice. Pharmaceutical depletion of MDSCs significantly exacerbated isoproterenol- and TAC-induced pathological cardiac remodeling and inflammation, whereas adoptive transfer of MDSCs prominently rescued isoproterenol- and TAC-induced HF. Consistently, administration of rapamycin significantly increased endogenous MDSCs by suppressing their differentiation and improved isoproterenol- and TAC-induced HF, but MDSC depletion mostly blocked beneficial rapamycin-mediated effects. Mechanistically, MDSC-secreted molecules suppressed isoproterenol-induced hypertrophy and proinflammatory gene expression in cardiomyocytes in a coculture system. Neutralization of interleukin-10 blunted both monocytic MDSC- and granulocytic MDSC–mediated anti-inflammatory and antihypertrophic effects, but treatment with a nitric oxide inhibitor only partially blocked the antihypertrophic effect of monocytic MDSCs.Conclusions:Our findings revealed a cardioprotective role of MDSCs in HF by their antihypertrophic effects on cardiomyocytes and anti-inflammatory effects through interleukin-10 and nitric oxide. Pharmacological targeting of MDSCs by rapamycin constitutes a promising therapeutic strategy for HF.

Sex Differences in Cardiovascular Pathophysiology [Primer]

Circulation - Lun, 09/07/2018 - 19:44
Consistent epidemiological data demonstrate that patients with heart failure with preserved ejection fraction (HFpEF) are more likely to be women than men. Exploring mechanisms behind this sex difference in heart failure epidemiology may enrich the understanding of underlying HFpEF pathophysiology and phenotypes, with the ultimate goal of identifying therapeutic approaches for the broader HFpEF population. In this review we evaluate the influence of sex on the key domains of cardiac structure and function, the systemic and pulmonary circulation, as well as extracardiac factors and comorbidities that may explain the predisposition of women to HFpEF. We highlight the potential role of factors exclusive to or more prevalent in women such as pregnancy, preeclampsia, and iron deficiency. Finally, we discuss existing controversies and gaps in knowledge, as well as the clinical importance of known sex differences in the context of the potential need for sex-specific diagnostic criteria, improved risk stratification models, and targeted therapies.

Atherosclerotic Cardiovascular Disease in South Asians in the United States: Epidemiology, Risk Factors, and Treatments: A Scientific Statement From the American Heart Association [AHA Scientific Statements]

Circulation - Lun, 02/07/2018 - 19:45
South Asians (from Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan, and Sri Lanka) make up one quarter of the world’s population and are one of the fastest-growing ethnic groups in the United States. Although native South Asians share genetic and cultural risk factors with South Asians abroad, South Asians in the United States can differ in socioeconomic status, education, healthcare behaviors, attitudes, and health insurance, which can affect their risk and the treatment and outcomes of atherosclerotic cardiovascular disease (ASCVD). South Asians have higher proportional mortality rates from ASCVD compared with other Asian groups and non-Hispanic whites, in contrast to the finding that Asian Americans (Asian Indian, Chinese, Filipino, Japanese, Korean, and Vietnamese) aggregated as a group are at lower risk of ASCVD, largely because of the lower risk observed in East Asian populations. Literature relevant to South Asian populations regarding demographics and risk factors, health behaviors, and interventions, including physical activity, diet, medications, and community strategies, is summarized. The evidence to date is that the biology of ASCVD is complex but is no different in South Asians than in any other racial/ethnic group. A majority of the risk in South Asians can be explained by the increased prevalence of known risk factors, especially those related to insulin resistance, and no unique risk factors in this population have been found. This scientific statement focuses on how ASCVD risk factors affect the South Asian population in order to make recommendations for clinical strategies to reduce disease and for directions for future research to reduce ASCVD in this population.

Trends in Hospitalizations and Survival of Acute Decompensated Heart Failure in Four US Communities (2005-2014) [Original Research Article]

Circulation - Lun, 02/07/2018 - 19:45
Background:Community trends of acute decompensated heart failure (ADHF) in diverse populations may differ by race and sex.Methods:The ARIC study (Atherosclerosis Risk in Communities) sampled heart failure-related hospitalizations (?55 years of age) in 4 US communities from 2005 to 2014 using International Classification of Diseases, Ninth Revision, Clinical Modification codes. ADHF hospitalizations were validated by standardized physician review and computer algorithm, yielding 40?173 events after accounting for sampling design (unweighted n=8746).Results:Of the ADHF hospitalizations, 50% had reduced ejection fraction, and 39% had preserved EF (HFpEF). HF with reduced ejection fraction was more common in black men and white men, whereas HFpEF was most common in white women. Average age-adjusted rates of ADHF were highest in blacks (38.1 per 1000 black men, 30.5 per 1000 black women), with rates differing by HF type and sex. ADHF rates increased over the 10 years (average annual percentage change: black women +4.3%, black men +3.7%, white women +1.9%, white men +2.6%), mostly reflecting more acute HFpEF. Age-adjusted 28-day and 1-year case fatality proportions were ?10% and 30%, respectively, similar across race-sex groups and HF types. Only blacks showed decreased 1-year mortality over time (average annual percentage change: black women –5.4%, black men –4.6%), with rates differing by HF type (average annual percentage change: black women HFpEF –7.1%, black men HF with reduced ejection fraction –4.7%).Conclusions:Between 2005 and 2014, trends in ADHF hospitalizations increased in 4 US communities, primarily driven by acute HFpEF. Survival at 1 year was poor regardless of EF but improved over time for black women and black men.

Long-Term Outcomes of Hypertrophic Cardiomyopathy Diagnosed During Childhood [Original Research Article]

Circulation - Lun, 02/07/2018 - 19:45
Background:Late survival and symptomatic status of children with hypertrophic cardiomyopathy have not been well defined. We examined long-term outcomes for pediatric hypertrophic cardiomyopathy.Methods:The National Australian Childhood Cardiomyopathy Study is a longitudinal population-based cohort study of children (0–10 years of age) diagnosed with cardiomyopathy between 1987 and 1996. The primary study end point was time to death or cardiac transplantation.Results:There were 80 patients with hypertrophic cardiomyopathy, with a median age at diagnosis of 0.48 (interquartile range, 0.1, 2.5) years. Freedom from death/transplantation was 86% (95% confidence interval [CI], 77.0–92.0) 1 year after presentation, 80% (95% CI, 69.0–87.0) at 10 years, and 78% (95% CI, 67.0–86.0) at 20 years. From multivariable analyses, risk factors for death/transplantation included symmetrical left ventricular hypertrophy at the time of diagnosis (hazard ratio, 4.20; 95% CI, 1.60–11.05; P=0.004), Noonan syndrome (hazard ratio, 2.88; 95% CI, 1.02–8.08; P=0.045), higher posterior wall thickness z score (hazard ratio, 1.45; 95% CI, 1.22–1.73; P<0.001), and lower fractional shortening z score (hazard ratio, 0.84; 95% CI, 0.74–0.95; P=0.005) during follow-up. Nineteen (23%) subjects underwent left ventricular myectomy. At a median of 15.7 years of follow-up, 27 (42%) of 63 survivors were treated with ?-blocker, and 13 (21%) had an implantable cardioverter-defibrillator.Conclusions:The highest risk of death or transplantation for children with hypertrophic cardiomyopathy is within 1 year after diagnosis, with low attrition rates thereafter. Many subjects receive medical, surgical, or device therapy.

Seafood Long-Chain n-3 Polyunsaturated Fatty Acids and Cardiovascular Disease: A Science Advisory From the American Heart Association [AHA Science Advisories]

Circulation - Lun, 02/07/2018 - 19:45
Since the 2002 American Heart Association scientific statement “Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease,” evidence from observational and experimental studies and from randomized controlled trials continues to emerge to further substantiate the beneficial effects of seafood long-chain n-3 polyunsaturated fatty acids and cardiovascular disease. A recent American Heart Association science advisory addressed the specific effect of n-3 polyunsaturated fatty acid supplementation on clinical cardiovascular events. This American Heart Association science advisory extends that review and offers further support to include n-3 polyunsaturated fatty acids from seafood consumption. Several potential mechanisms have been investigated, including antiarrhythmic, anti-inflammatory, hematologic, and endothelial, although for most, longer-term dietary trials of seafood are warranted to substantiate the benefit of seafood as a replacement for other important sources of macronutrients. The present science advisory reviews this evidence and makes a suggestion in the context of the 2015–2020 Dietary Guidelines for Americans and in consideration of other constituents of seafood and the impact on sustainability. We conclude that 1 to 2 seafood meals per week be included to reduce the risk of congestive heart failure, coronary heart disease, ischemic stroke, and sudden cardiac death, especially when seafood replaces the intake of less healthy foods.

Oral Anticoagulation in Very Elderly Patients With Atrial Fibrillation [Original Research Article]

Circulation - Lun, 02/07/2018 - 19:45
Background:Stroke prevention with oral anticoagulants (OACs) is the cornerstone for the management of atrial fibrillation (AF). However, data about the use of OACs among patients ?90 years of age are limited. We aimed to investigate the risk of ischemic stroke and intracranial hemorrhage (ICH) and the net clinical benefit of OAC treatment for very elderly patients with AF (?90 years of age).Methods:This study used the National Health Insurance Research Database in Taiwan. Risks of ischemic stroke and ICH were compared between 11?064 and 14?658 patients with and without AF ?90 years of age without antithrombotic therapy from 1996 to 2011. Patients with AF (n=15?756) were divided into 3 groups (no treatment, antiplatelet agents, and warfarin), and the risks of stroke and ICH were analyzed. The risks of ischemic stroke and ICH were further compared between patients treated with warfarin and nonvitamin K antagonist OACs (NOACs) from 2012 to 2015 when NOACs were available in Taiwan.Results:Compared with patients without AF, patients with AF had an increased risk of ischemic stroke (event number/patient number, incidence = 742/11?064, 5.75%/y versus 1399/14?658, 3.00%/y; hazard ratio, 1.93; 95% confidence interval, 1.74–2.14) and similar risk of ICH (131/11?064, 0.97%/y versus 206/14?658, 0.54%/y; hazard ratio, 0.85; 95% confidence interval, 0.66–1.09) in competing risk analysis for mortality. Among patients with AF, warfarin use was associated with a lower stroke risk (39/617, 3.83%/y versus 742/11?064, 5.75%/y; hazard ratio, 0.69; 95% confidence interval, 0.49–0.96 in a competing risk model), with no difference in ICH risk compared with nontreatment. When compared with no antithrombotic therapy or antiplatelet drugs, warfarin was associated with a positive net clinical benefit. These findings persisted in propensity-matched analyses. Compared with warfarin, NOACs were associated with a lower risk of ICH (4/978, 0.42%/y versus 19/768, 1.63%/y; hazard ratio, 0.32; 95% confidence interval, 0.10–0.97 in a competing risk model), with no difference in risk of ischemic stroke.Conclusions:Among patients with AF ?90 years of age, warfarin was associated with a lower risk of ischemic stroke and positive net clinical benefit. Compared with warfarin, NOACs were associated with a lower risk of ICH. Thus, OACs may still be considered as thromboprophylaxis for elderly patients, with NOACs being the more favorable choice.

Novel Adipokine, FAM19A5, Inhibits Neointima Formation After Injury Through Sphingosine-1-Phosphate Receptor 2 [Original Research Article]

Circulation - Lun, 02/07/2018 - 19:45
Background:Obesity plays crucial roles in the development of cardiovascular diseases. However, the mechanisms that link obesity and cardiovascular diseases remain elusive. Compelling evidence indicates that adipokines play an important role in obesity-related cardiovascular diseases. Here, we found a new adipokine-named family with sequence similarity 19, member A5 (FAM19A5), a protein with unknown function that was predicted to be distantly related to the CC-chemokine family. We aimed to test whether adipose-derived FAM19A5 regulates vascular pathology on injury.Methods:DNA cloning, protein expression, purification, and N-terminal sequencing were applied to characterize FAM19A5. Adenovirus infection and siRNA transfection were performed to regulate FAM19A5 expression. Balloon and wire injury were performed in vivo on the rat carotid arteries and mouse femoral arteries, respectively. Bioinformatics analysis, radioactive ligand-receptor binding assays, receptor internalization, and calcium mobilization assays were used to identify the functional receptor for FAM19A5.Results:We first characterized FAM19A5 as a secreted protein, and the first 43 N-terminal amino acids were the signal peptides. Both FAM19A5 mRNA and protein were abundantly expressed in the adipose tissue but were downregulated in obese mice. Overexpression of FAM19A5 markedly inhibited vascular smooth muscle cell proliferation and migration and neointima formation in the carotid arteries of balloon-injured rats. Accordingly, FAM19A5 silencing in adipocytes significantly promoted vascular smooth muscle cell activation. Adipose-specific FAM19A5 transgenic mice showed greater attenuation of neointima formation compared with wild-type littermates fed with or without Western-style diet. We further revealed that sphingosine-1-phosphate receptor 2 was the functional receptor for FAM19A5, with a dissociation constant (Kd) of 0.634 nmol/L. Inhibition of sphingosine-1-phosphate receptor 2 or its downstream G12/13-RhoA signaling circumvented the suppressive effects of FAM19A5 on vascular smooth muscle cell proliferation and migration.Conclusions:We revealed that a novel adipokine, FAM19A5, was capable of inhibiting postinjury neointima formation via sphingosine-1-phosphate receptor 2-G12/13-RhoA signaling. Downregulation of FAM19A5 during obesity may trigger cardiometabolic diseases.
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