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Sex steroids mediate discrete effects on HDL cholesterol efflux capacity and particle concentration in healthy men.
Rubinow, KB, Vaisar, T, Chao, JH, Heinecke, JW, Page, ST
Journal of clinical lipidology. 2018;(4):1072-1082
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Abstract
BACKGROUND Exogenous testosterone decreases serum concentrations of high-density lipoprotein cholesterol (HDL-C) in men, but whether this alters cardiovascular risk is uncertain. OBJECTIVE To investigate the effects of testosterone and estradiol on HDL particle concentration (HDL-Pima) and metrics of HDL function. METHODS We enrolled 53 healthy men, 19 to 55 years of age, in a double-blinded, placebo-controlled, randomized trial. Subjects were rendered medically castrate using the GnRH receptor antagonist acyline and administered either (1) placebo gel, (2) low-dose transdermal testosterone gel (1.62%, 1.25 g), (3) full replacement dose testosterone gel (1.62%, 5 g) or (4) full replacement dose testosterone gel together with an aromatase inhibitor for 4 weeks. At baseline and end of treatment, serum HDL total macrophage and ABCA1-specific cholesterol efflux capacity (CEC), HDL-Pima and size, and HDL protein composition were determined. RESULTS Significant differences in serum HDL-C were observed with treatment across groups (P = .01 in overall repeated measures ANOVA), with increases in HDL-C seen after both complete and partial testosterone deprivation. Medical castration increased total HDL-Pima (median [interquartile range] 19.1 [1.8] nmol/L at baseline vs 21.3 [3.1] nmol/L at week 4, P = .006). However, corresponding changes in total macrophage CEC and ABCA1-specific CEC were not observed. Change in serum 17β-estradiol concentration correlated with change in total macrophage CEC (β = 0.33 per 10 pg/mL change in serum 17β-estradiol, P = .03). CONCLUSIONS Testosterone deprivation in healthy men leads to a dissociation between changes in serum HDL-C and HDL CEC. Changes in serum HDL-C specifically due to testosterone exposure may not reflect changes in HDL function.
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Maintenance of Lost Weight and Long-Term Management of Obesity.
Hall, KD, Kahan, S
The Medical clinics of North America. 2018;(1):183-197
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Abstract
Weight loss can be achieved through a variety of modalities, but long-term maintenance of lost weight is much more challenging. Obesity interventions typically result in early weight loss followed by a weight plateau and progressive regain. This review describes current understanding of the biological, behavioral, and environmental factors driving this near-ubiquitous body weight trajectory and the implications for long-term weight management. Treatment of obesity requires ongoing clinical attention and weight maintenance-specific counseling to support sustainable healthful behaviors and positive weight regulation.
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ER-Mitochondria Microdomains in Cardiac Ischemia-Reperfusion Injury: A Fresh Perspective.
Zhou, H, Wang, S, Hu, S, Chen, Y, Ren, J
Frontiers in physiology. 2018;:755
Abstract
The mitochondrial and endoplasmic reticulum (ER) homeostasis is pivotal to the maintenance of an array of physiological processes. The physical contact and association between ER and mitochondria, known as the ER-mitochondria microdomains or mitochondria-associated ER membrane (MAM), temporally and spatially regulates the mitochondria/ER structure and function. More evidence suggests a role for MAMs in energy production, cellular contraction and mobility, and normal extracellular signal transmission. In pathological states, such as cardiac ischemia-reperfusion (I/R injury), this ER-mitochondria microdomains may act to participate in the cellular redox imbalance, ER stress, mitochondrial injury, energy deletion, and programmed cell death. From a therapeutic perspective, a better understanding of the cellular and molecular mechanisms of the pathogenic ER-mitochondria contact should help to identify potential therapeutic target for cardiac I/R injury and other cardiovascular diseases and also pave the road to new treatment modalities pertinent for the treatment of reperfusion damage in clinical practice. This review will mainly focus on the possible signaling pathways involved in the regulation of the ER-mitochondria contact. In particular, we will summarize the downstream signaling modalities influenced by ER-mitochondria microdomains, for example, mitochondrial fission, mitophagy, calcium balance, oxidative stress, and programmed cell death in details.
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Arterial Stiffness: A Prognostic Marker in Coronary Heart Disease. Available Methods and Clinical Application.
Bonarjee, VVS
Frontiers in cardiovascular medicine. 2018;:64
Abstract
Multiple biomarkers may predict short and long-term prognosis in patients with coronary heart disease, but their impact is limited when used in addition to established risk factors such blood pressure, cholesterol levels, diabetes mellitus, smoking as well as age and sex. Arteries are an integral part of the cardiovascular (CV) system. Arterial stiffness has been shown to be a predictor of cardiovascular events and mortality independent of traditional risk factors. It has also been shown that increased arterial stiffness may predict cardiovascular events in asymptomatic individuals without overt cardiovascular disease. Measuring arterial stiffness may, therefore, identify patients at risk at an early stage. Antihypertensive treatment has been shown to reduce arterial stiffness beyond its antihypertensive effect. Arterial stiffness could, therefore, be a surrogate marker of treatment that relates to prognosis. Arterial stiffness has mostly been used in research protocols, and its use as a prognostic indicator in clinical practice is still uncommon. Several methods exist that can determine parameters related to arterial stiffness, both local and in specific artery beds such as the aorta. In this brief review we present methods to evaluate arterial stiffness, their clinical utility, limitations and the advantages of a novel method, the Cardio-Ankle Vascular Index. Easier and more reproducible methods to evaluate arterial stiffness may increase the use of parameter as a risk factor for coronary heart disease in common clinical practice.
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In silico prediction of nonpermissive HLA-DPB1 mismatches in unrelated HCT by functional distance.
Arrieta-Bolaños, E, Crivello, P, Shaw, BE, Ahn, KW, Wang, HL, Verneris, MR, Hsu, KC, Pidala, J, Lee, SJ, Fleischhauer, K, et al
Blood advances. 2018;(14):1773-1783
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Abstract
In silico prediction of high-risk donor-recipient HLA mismatches after unrelated donor (UD) hematopoietic cell transplantation (HCT) is an attractive, yet elusive, objective. Nonpermissive T-cell epitope (TCE) group mismatches were defined by alloreactive T-cell cross-reactivity for 52/80 HLA-DPB1 alleles (TCE-X). More recently, a numerical functional distance (FD) scoring system for in silico prediction of TCE groups based on the median impact of exon 2-encoded amino acid polymorphism on T-cell alloreactivity was developed for all DPB1 alleles (TCE-FD), including the 28/80 common alleles not assigned by TCE-X. We compared clinical outcome associations of nonpermissive DPB1 mismatches defined by TCE-X or TCE-FD in 8/8 HLA-matched UD-HCT for acute leukemia, myelodysplastic syndrome, and chronic myelogenous leukemia between 1999 and 2011 (N = 2730). Concordance between the 2 models was 92.3%, with most differences arising from DPB1*06:01 and DPB1*19:01 being differently assigned by TCE-X and TCE-FD. In both models, nonpermissive mismatches were associated with reduced overall survival (hazard ratio [HR], 1.15, P < .006 and HR, 1.12, P < .03), increased transplant-related mortality (HR, 1.31, P < .001 and HR, 1.26, P < .001) as well as acute (HR, 1.16, P < .02 and HR, 1.22, P < .001) and chronic (HR, 1.20, P < .003 and HR, 1.22, P < .001) graft-versus-host disease (GVHD). We show that in silico prediction of nonpermissive DPB1 mismatches significantly associated with major transplant outcomes is feasible for any DPB1 allele with known exon 2 sequence based on experimentally elaborated FD scores. This proof-of-principle observation opens new avenues for developing HLA risk-prediction models in HCT and has practical implications for UD searches.
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Safety and Efficacy of Fludrocortisone in the Treatment of Cerebral Salt Wasting in Patients With Tuberculous Meningitis: A Randomized Clinical Trial.
Misra, UK, Kalita, J, Kumar, M
JAMA neurology. 2018;(11):1383-1391
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Abstract
IMPORTANCE Tuberculous meningitis is associated with high frequency of cerebral salt wasting. There is a paucity of objective information regarding the best method of treatment of this condition. OBJECTIVE To evaluate the efficacy and safety of fludrocortisone in the treatment of cerebral salt wasting in patients with tuberculous meningitis. DESIGN, SETTING, AND PARTICIPANTS This is a single-center, open-label, randomized clinical trial conducted from October 2015 to April 2017 in India. Patients were randomized in a 1:1 ratio to arms receiving saline only or saline plus fludrocortisone, in addition to a standard treatment of 4 antitubercular drugs, prednisolone, and aspirin. The 2 arms were matched for demographic, clinical, and magnetic resonance imaging findings. The patients were followed up for at least 6 months. INTERVENTIONS Patients were randomized to a 0.9% solution of intravenous saline with 5 to 12 g per day of oral salt supplementation, with or without the addition of 0.1 to 0.4 mg of fludrocortisone per day. MAIN OUTCOMES AND MEASURES The primary end point was the time needed to correct serum sodium levels; secondary end points were in-hospital deaths, disability at 3 months, disability at 6 months, occurence of stroke, and serious adverse reactions. RESULTS Ninety-three patients with suspected tuberculous meningitis were recruited; 12 did not meet the inclusion criteria, including 4 with alternate diagnoses. A total of 37 patients with cerebral salt wasting were eligible for the study. One refused to participate, and therefore 36 patients were included, with 18 randomized to each group. The median (range) age was 30 (20-46) years, and 19 were male (52.8%). Those receiving fludrocortisone regained normal serum sodium levels after 4 days, significantly earlier than those receiving saline only (15 days; P = .004). In an intention-to-treat analysis, hospital mortality, disability at 3 months, and disability at 6 months did not differ significantly, but fewer infarcts occurred in the deep border zone in the group receiving fludrocortisone (1 of 18 [6%]) vs those in the control arm (6 of 18 [33%]; P = .04). Fludrocortisone was associated with severe hypokalemia and hypertension in 2 patients each, and pulmonary edema occurred in 1 patient. These adverse reactions necessitated discontinuation of fludrocortisone in 2 patients. CONCLUSIONS AND RELEVANCE Fludrocortisone results in earlier normalization of serum sodium levels, but did not affect outcomes at 6 months. Fludrocortisone had to be withdrawn in 2 patients because of severe adverse effects. This study provides class II evidence on the role of fludrocortisone in treatment of hyponatremia associated with cerebral salt wasting in patients with tuberculous meningitis. TRIAL REGISTRATION Clinical Trials Registry of India (ctri.nic.in) Identifier: CTRI/2017/10/010255.
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Exploring the complexity: the interplay between the angiotensin-converting enzyme insertion/deletion polymorphism and the sympathetic response to hemodialysis.
Ribas Ribeiro, L, Flores de Oliveira, J, Bueno Orcy, R, Castilho Barros, C, Damé Hense, J, Santos, F, Irigoyen, MC, Gonzalez, MC, Oses, JP, Böhlke, M
American journal of physiology. Heart and circulatory physiology. 2018;(4):H1002-H1011
Abstract
Patients on hemodialysis (HD) are at increased risk for arrhythmias and sudden cardiac death. Autonomic nervous system (ANS) dysfunction seems to participate in the arrhythmogenic process. Genetic factors have an impact on ANS modulation, but the specific role of the insertion/deletion (I/D) polymorphism in the gene for angiotensin-converting enzyme (ACE) has not been investigated. Since the D allele increases gene expression, it is a candidate polymorphism to interact with the ANS. The aim of the present study was to compare the behavior of heart rate variability (HRV) during HD, as a surrogate for ANS response to stressors, between the ACE genotypes. In a sample of patients with chronic kidney disease I/D ACE genotypes were assessed with PCR and HRV was measured before, in the second hour, and after a HD session. HRV parameters in the time and frequency domains were analyzed by repeated-measures mixed models according to the time of measurement and ACE polymorphism. HRV parameters in the frequency domain presented significantly different variations during the HD session between patients with or without the D allele. Only patients with the II genotype presented an increase in low-frequency normalized units and in the low frequency-to-high frequency ratio throughout HD. Patients with the II genotype seemed to have a more physiological response to the volemic and electrolytic changes that occur during HD, with greater sympathetic activation than patients with ID and DD genotypes. NEW & NOTEWORTHY Adding to the effort to understand the complexity of cardiovascular system regulation, we have found that the autonomic nervous system response to the acute volume removal during hemodialysis may be different between angiotensin-converting enzyme insertion/deletion polymorphisms. To our knowledge, this is the first time that this specific interaction was analyzed during a volume removal intervention.
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The diagnostic accuracy of circulating tumor DNA for the detection of EGFR-T790M mutation in NSCLC: a systematic review and meta-analysis.
Passiglia, F, Rizzo, S, Di Maio, M, Galvano, A, Badalamenti, G, Listì, A, Gulotta, L, Castiglia, M, Fulfaro, F, Bazan, V, et al
Scientific reports. 2018;(1):13379
Abstract
This pooled analysis aims at evaluating the diagnostic accuracy of circulating tumor (ct) DNA for the detection of EGFR-T790M mutation in NSCLC patients who progressed after EGFR-TKIs. Data from all published studies, reporting both sensitivity and specificity of plasma-based EGFR-T790M mutation testing by ctDNA were collected by searching in PubMed, Cochrane Library, American Society of Clinical Oncology, European Society of Medical Oncology and World Conference of Lung Cancer meeting proceedings. A total of twenty-one studies, with 1639 patients, were eligible. The pooled sensitivity of ctDNA analysis was 0.67 (95% CI: 0.64-0.70) and the pooled specificity was 0.80 (95% CI: 0.77-0.83). The pooled positive predictive value (PPV) was 0.85 (95% CI: 0.82-0.87) and the pooled negative predictive value (NPV) was 0.60 (95% CI: 0.56-0.63). The positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 2.67 (95% CI: 1.86-3.82) and 0.46 (95% CI: 0.38-0.54), respectively. The pooled diagnostic odds ratio (DOR) was 7.27 (4.39-12.05) and the area under the curve (AUC) of the summary receiver operating characteristics (sROC) curve was 0.77. The ctDNA analysis represents a promising, non-invasive approach to detect and monitor the T790M mutation status in NSCLC patients. Development of standardized methodologies and clinical validation are recommended.
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Mechanism of doxorubicin cardiotoxicity evaluated by integrating multiple molecular effects into a biophysical model.
Fernandez-Chas, M, Curtis, MJ, Niederer, SA
British journal of pharmacology. 2018;(5):763-781
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BACKGROUND AND PURPOSE Doxorubicin (DOX) is an effective cancer therapeutic agent but causes therapy-limiting cardiotoxicity. The effects of DOX and its metabolite doxorubicinol (DOXL) on individual channels have been well characterized in isolation. However, it is unknown how the action and interaction of affected channels combine to generate the phenotypic cardiotoxic outcome. We sought to develop an in silico model that links drug effects on channels to action potential duration (APD) and intracellular Ca2+ concentration in order to address this gap in knowledge. EXPERIMENTAL APPROACH We first propose two methods to obtain, from published values, consensus drug effects on the currents of individual channels, transporters and pumps. Separately, we obtained equivalent values for APD and Ca2+ concentration (the readouts used as surrogates for cardiotoxicity). Once derived, the consensus effects on the currents were incorporated into established biophysical models of the cardiac myocyte and were refined adjusting the sarcoplasmic reticulum Ca2+ leak current (ILeak ) until the consensus effects on APD and Ca2+ dynamics were replicated. Using factorial analysis, we then quantified the relative contribution of each channel to DOX and DOXL cardiotoxicity. KEY RESULTS The factorial analysis identified the rapid delayed rectifying K+ current, the L-type Ca2+ current and the sarcoplasmic reticulum ILeak as the targets primarily responsible for the cardiotoxic effects on APD and Ca2+ dynamics. CONCLUSIONS AND IMPLICATIONS This study provides insight into the mechanisms of DOX-induced cardiotoxicity and a framework for the development of future diagnostic and therapeutic strategies.
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The Role of Sirtuins in Antioxidant and Redox Signaling.
Singh, CK, Chhabra, G, Ndiaye, MA, Garcia-Peterson, LM, Mack, NJ, Ahmad, N
Antioxidants & redox signaling. 2018;(8):643-661
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SIGNIFICANCE Antioxidant and redox signaling (ARS) events are regulated by critical molecules that modulate antioxidants, reactive oxygen species (ROS) or reactive nitrogen species (RNS), and/or oxidative stress within the cell. Imbalances in these molecules can disturb cellular functions to become pathogenic. Sirtuins serve as important regulators of ARS in cells. Recent Advances: Sirtuins (SIRTs 1-7) are a family of nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylases with the ability to deacetylate histone and nonhistone targets. Recent studies show that sirtuins modulate the regulation of a variety of cellular processes associated with ARS. SIRT1, SIRT3, and SIRT5 protect the cell from ROS, and SIRT2, SIRT6, and SIRT7 modulate key oxidative stress genes and mechanisms. Interestingly, SIRT4 has been shown to induce ROS production and has antioxidative roles as well. CRITICAL ISSUES A complete understanding of the roles of sirtuins in redox homeostasis of the cell is very important to understand the normal functioning as well as pathological manifestations. In this review, we have provided a critical discussion on the role of sirtuins in the regulation of ARS. We have also discussed mechanistic interactions among different sirtuins. Indeed, a complete understanding of sirtuin biology could be critical at multiple fronts. FUTURE DIRECTIONS Sirtuins are emerging to be important in normal mammalian physiology and in a variety of oxidative stress-mediated pathological situations. Studies are needed to dissect the mechanisms of sirtuins in maintaining redox homeostasis. Efforts are also required to assess the targetability of sirtuins in the management of redox-regulated diseases. Antioxid. Redox Signal. 28, 643-661.