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1.
Pitfalls and Misinterpretations of Cardiac Findings on PET/CT Imaging: A Careful Look at the Heart in Oncology Patients.
Betancourt Cuellar, SL, Palacio, D, Benveniste, MF, Carter, BW, Gladish, G
Current problems in diagnostic radiology. 2019;(2):172-183
Abstract
Positron emission tomography (PET) computed tomography (CT) with 2-[fluorine-18] fluoro-2-deoxy-d-glucose (FDG) has been established as an effective modality for evaluation of cancer. Interpretations of patterns of physiologic 18F-FDG uptake by the heart is particularly difficult given the wide normal variations of 18F-FDG metabolic activity observed. Atypical patterns of focal or diffuse physiologic cardiac 18F-FDG uptake and post-therapeutic effects after radiation therapy, systemic diseases, or cardiomyopathy may also be confused with malignant disease on 18F-FDG PET/CT. In this article, we review the variations of normal cardiac 18F-FDG uptake observed in oncology patients and the appearances of other patterns of pathologic metabolic activity, related or not related to the malignancy being investigated, that may lead to false-negative and false-positive results.
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2.
Biochemical characterization of the catecholaldehyde reactivity of L-carnosine and its therapeutic potential in human myocardium.
Nelson, MM, Builta, ZJ, Monroe, TB, Doorn, JA, Anderson, EJ
Amino acids. 2019;(1):97-102
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Abstract
Oxidative deamination of norepinephrine (NE) and dopamine (DA) by monoamine oxidase (MAO) generates the catecholaldehydes 3,4-dihydroxyphenylglycolaldehyde (DOPEGAL) and 3,4-dihydroxyphenylacetaldehyde (DOPAL), respectively, and H2O2. Catecholaldehydes are highly reactive electrophiles that have been implicated as causal factors in the etiology of neurodegenerative diseases and cardiac injury from ischemia and diabetes. The reactivity of both catechol and aldehyde groups enables the catecholaldehdyes to cross-link proteins and other biological molecules. Carnosine is a β-alanyl-histidine dipeptide found in millimolar concentrations in brain and myocardium. It is well known to detoxify aldehydes formed from oxidized lipids and sugars, yet the reactivity of carnosine with catecholaldehydes has never been reported. Here, we investigated the ability of carnosine to form conjugates with DOPAL and DOPEGAL. Both catecholaldehydes were highly reactive towards L-cysteine (L-Cys), as well as carnosine; however, glutathione (GSH) showed essentially no reactivity towards DOPAL. In contrast, GSH readily reacted with the lipid peroxidation product 4-hydroxy-2-nonenal (4HNE), while carnosine showed low reactivity to 4HNE by comparison. To determine whether carnosine mitigates catecholaldehyde toxicity, samples of atrial myocardium were collected from patients undergoing elective cardiac surgery. Using permeabilized myofibers prepared from this tissue, mitochondrial respiration analysis revealed a concentration-dependent decrease in ADP-stimulated respiration with DOPAL. Pre-incubation with carnosine, but not GSH or L-Cys, significantly reduced this effect (p < 0.05). Carnosine was also able to block formation of catecholaldehyde protein adducts in isolated human cardiac mitochondria treated with NE. These findings demonstrate the unique reactivity of carnosine towards catecholaldehydes and, therefore, suggest a novel and distinct biological role for histidine dipeptides in this detoxification reaction. The therapeutic potential of carnosine in diseases associated with catecholamine-related toxicity is worthy of further examination.
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Single-Channel Properties of the ROMK-Pore-Forming Subunit of the Mitochondrial ATP-Sensitive Potassium Channel.
Laskowski, M, Augustynek, B, Bednarczyk, P, Żochowska, M, Kalisz, J, O'Rourke, B, Szewczyk, A, Kulawiak, B
International journal of molecular sciences. 2019;(21)
Abstract
An increased flux of potassium ions into the mitochondrial matrix through the ATP-sensitive potassium channel (mitoKATP) has been shown to provide protection against ischemia-reperfusion injury. Recently, it was proposed that the mitochondrial-targeted isoform of the renal outer medullary potassium channel (ROMK) protein creates a pore-forming subunit of mitoKATP in heart mitochondria. Our research focuses on the properties of mitoKATP from heart-derived H9c2 cells. For the first time, we detected single-channel activity and describe the pharmacology of mitoKATP in the H9c2 heart-derived cells. The patch-clamping of mitoplasts from wild type (WT) and cells overexpressing ROMK2 revealed the existence of a potassium channel that exhibits the same basic properties previously attributed to mitoKATP. ROMK2 overexpression resulted in a significant increase of mitoKATP activity. The conductance of both channels in symmetric 150/150 mM KCl was around 97 ± 2 pS in WT cells and 94 ± 3 pS in cells overexpressing ROMK2. The channels were inhibited by 5-hydroxydecanoic acid (a mitoKATP inhibitor) and by Tertiapin Q (an inhibitor of both the ROMK-type channels and mitoKATP). Additionally, mitoKATP from cells overexpressing ROMK2 were inhibited by ATP/Mg2+ and activated by diazoxide. We used an assay based on proteinase K to examine the topology of the channel in the inner mitochondrial membrane and found that both termini of the protein localized to the mitochondrial matrix. We conclude that the observed activity of the channel formed by the ROMK protein corresponds to the electrophysiological and pharmacological properties of mitoKATP.
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Association Between Adherence To The French Dietary Guidelines And Lower Resting Heart Rate, Longer Diastole Duration, And Lower Myocardial Oxygen Consumption. The NUTRIVASC Study.
Fysekidis, M, Kesse-Guyot, E, Valensi, P, Arnault, N, Galan, P, Hercberg, S, Cosson, E
Vascular health and risk management. 2019;:463-475
Abstract
BACKGROUND To investigate whether chronic adherence to the French Nutrition and Health Program (PNNS) guidelines was associated with better cardiovascular health. METHODS A study nested within the SU.VI.MAX2 cohort was conducted on participants without cardiovascular risk factors. Long-term adherence to the PNNS guidelines was estimated using validated dietary scores from 2007 and 2012. Individuals who did (PNNS+) and did not (PNNS-) continuously adhere to the PNNS guidelines were included. Applanation tonometry, impedance cardiography, laser doppler flowmetry, heart rate, heart rate variability, endothelial function was used for the assessment of cardiovascular health. RESULTS A total of 49 subjects (mean age 65.4 ± 5.6 years, 75.5% women) had been included. Those in the PNNS+ group (n=26) were older, had a higher BMI and fat mass than those in the PNNS- group, both groups had similar metabolic parameters. After adjusting for sex, age, and BMI, PNNS+ subjects were found to have a lower heart rate (60.2 ± 8.0 vs 64.3 ± 8.4 beats/min, p=0.042), a lower heart rate × systolic blood pressure product (7166 ± 1323 vs 7788 ± 1680 beats× mmHg/min, p = 0.009), a longer diastole duration (66.7 ± 3.1% vs 64.6 ± 4.1% of the cardiac cycle duration, p=0.049), and a shorter tension-time index (2145 ± 489 vs 2307 ± 428 ms * mmHg, p=0.018) compared to the PNNS- group. CONCLUSION Long-term adherence to the PNNS guidelines had a favorable impact on heart rate, diastole duration, and myocardial oxygen consumption. CLINICAL TRIAL REGISTRATION NUMBER NCT01579409.
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Linking the heart and the brain: Neurodevelopmental disorders in patients with catecholaminergic polymorphic ventricular tachycardia.
Lieve, KVV, Verhagen, JMA, Wei, J, Bos, JM, van der Werf, C, Rosés I Noguer, F, Mancini, GMS, Guo, W, Wang, R, van den Heuvel, F, et al
Heart rhythm. 2019;(2):220-228
Abstract
BACKGROUND Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an uncommon inherited arrhythmia disorder characterized by adrenergically evoked ventricular arrhythmias. Mutations in the cardiac calcium release channel/ryanodine receptor gene (RYR2) are identified in the majority of patients with CPVT. RyR2 is also the major RyR isoform expressed in the brain. OBJECTIVE The purpose of this study was to estimate the prevalence of intellectual disability (ID) and other neurodevelopmental disorders (NDDs) in RYR2-associated CPVT (CPVT1) and to study the characteristics of these patients. METHODS We reviewed the medical records of all CPVT1 patients from 12 international centers and analyzed the characteristics of all CPVT1 patients with concomitant NDDs. We functionally characterized the mutations to assess their response to caffeine activation. We did not correct for potential confounders. RESULTS Among 421 CPVT1 patients, we identified 34 patients with ID (8%; 95% confidence interval 6%-11%). Median age at diagnosis was 9.3 years (interquartile range 7.0-14.5). Parents for 24 of 34 patients were available for genetic testing, and 13 of 24 (54%) had a de novo mutation. Severity of ID ranged from mild to severe and was accompanied by other NDDs in 9 patients (26%). Functionally, the ID-associated mutations showed a markedly enhanced response of RyR2 to activation by caffeine. Seventeen patients (50%) also had supraventricular arrhythmias. During median follow-up of 8.4 years (interquartile range 1.8-12.4), 15 patients (45%) experienced an arrhythmic event despite adequate therapy. CONCLUSION Our study indicates that ID is more prevalent among CPVT1 patients (8%) than in the general population (1%-3%). This subgroup of CPVT1 patients reveals a malignant cardiac phenotype with marked supraventricular and ventricular arrhythmias.
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A Mathematical Model of the Human Cardiac Na+ Channel.
Asfaw, TN, Bondarenko, VE
The Journal of membrane biology. 2019;(1):77-103
Abstract
Sodium ion channel is a membrane protein that plays an important role in excitable cells, as it is responsible for the initiation of action potentials. Understanding the electrical characteristics of sodium channels is essential in predicting their behavior under different physiological conditions. We investigated several Markov models for the human cardiac sodium channel NaV1.5 to derive a minimal mathematical model that describes the reported experimental data obtained using major voltage clamp protocols. We obtained simulation results for peak current-voltage relationships, the voltage dependence of normalized ion channel conductance, steady-state inactivation, activation and deactivation kinetics, fast and slow inactivation kinetics, and recovery from inactivation kinetics. Good agreement with the experimental data provides us with the mechanisms of the fast and slow inactivation of the human sodium channel and the coupling of its inactivation states to the closed and open states in the activation pathway.
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Effect of ticagrelor on brain natriuretic peptide, heart rate and myocardial enzymes in patients with coronary atherosclerotic heart disease after stenting.
Jia, D, Qin, B, Wei, X
Pakistan journal of pharmaceutical sciences. 2019;(3 Special):1371-1373
Abstract
The main aim of the current work was to investigate the application of ticagrelor in patients with coronary atherosclerotic heart disease (CAHD) and its effects on brain natriuretic peptide (BNP), heart rate (HR) and myocardial enzymes. Seventy-four postoperative patients who underwent stenting for CAHD were selected as subjects, randomly divided into control group (n=37) and observation group (n=37). The control group was treated with clopidogrel after operation, while the observation group was given ticagrelor treatment. The plasma BNP, HR, myocardial zymogram and adverse cardiac events were compared between the two groups. SPSS18.0 software was used for statistical analysis and the count data was analyzed by χ2 test and the measurement data was detected by t-test The levels of BNP, HR, creatine kinase isoenzyme (CK-MB) and troponin (cTnI) in the observation group were all lower than those in the control group at 3 months after treatment (P<0.05). There was no significant difference in the incidence of myocardial infarction, angina pectoris and arrhythmia between the two groups at 3 months after treatment (P>0.05). The utilization of ticagrelor in patients with postoperative stenting for CAHD improved the BNP, HR and myocardial enzyme level in patients, and also reduced the incidence of adverse cardiac events.
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Potential Mechanisms of Sodium-Glucose Co-Transporter 2 Inhibitor-Related Cardiovascular Benefits.
Verma, S
The American journal of cardiology. 2019;:S36-S44
Abstract
The findings of recent clinical trials have shown that sodium-glucose co-transporter 2 (SGLT2) inhibitors produce effects beyond glucose lowering and have demonstrated beneficial cardiovascular effects that have been observed across a broad range of patients with type 2 diabetes mellitus. In particular, the cardiovascular benefit results largely from substantial and early effects of SGLT2 inhibition on cardiovascular death and hospitalization for heart failure. Recent cardiovascular outcomes trials (CVOTs) have also shown that relative risk reductions in cardiovascular outcomes were observed with SGLT2 inhibition both in patients with current and prior heart failure. Since the observed reductions of cardiovascular outcomes with SGLT2 inhibitor therapy were observed much earlier than would be expected by an anti-atherosclerotic effect, these results have led to speculation about the potential underlying pathways. Suggested mechanisms include natriuresis and osmotic diuresis; reductions in inflammation, oxidative stress, and arterial stiffness; reductions in blood pressure and body weight; and possible renoprotective effects. These effects could produce cardiovascular benefits through a range of cardiac effects, including reduction in left ventricular load, attenuation of cardiac fibrosis and inflammation, and improved myocardial energy production. Other possible mechanisms include inhibition of sodium-hydrogen exchange, increases in erythropoietin levels, and reduction in myocardial ischemia or reperfusion injury. It is likely that a range of mechanisms underlie the observed cardiovascular benefits of SGLT2 inhibitors; further elucidation of these mechanisms will be answered by ongoing research.
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Myocardial Iron Overload in Sickle Cell Disease: A Rare But Potentially Fatal Complication of Transfusion.
Tavares, AHJ, Benites, BD, Fertrin, KY
Transfusion medicine reviews. 2019;(3):170-175
Abstract
Sickle cell disease (SCD) is a frequent indication for chronic transfusion, which can cause iron overload. Excess iron often affects the liver, but not the heart in SCD. Magnetic resonance (MR) is recommended to detect myocardial iron overload (MIO) but its elevated cost requires optimized indication. We aimed to compile all published data on MIO in SCD upon the description of a fatal case of severe MIO in our institution, and to determine associated risk factors. We performed a systematic review using the PRISMA guidelines in two databases (PubMed and Web of Science). Inclusion criteria were publication in English, patients diagnosed with SCD, and reporting ferritin and MIO by MR. Twenty publications reported on 865 SCD adult and pediatric patients, with at least 10 other cases of MIO. The prevalence of MIO in chronically transfused SCD patients can be estimated to be 3% or less, and is associated with high transfusion burden, top-up transfusions, and low adherence to iron chelation. Cardiac siderosis in SCD is rarely reported, and increased awareness with better use of the available screening tools are necessary. Prospective studies should define the recommended chelation regimens depending on the severity of MIO.
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A Low-Glycemic, Mediterranean Diet and Lifestyle Modification Program with Targeted Nutraceuticals Reduces Body Weight, Improves Cardiometabolic Variables and Longevity Biomarkers in Overweight Subjects: A 13-Week Observational Trial.
Tripp, ML, Dahlberg, CJ, Eliason, S, Lamb, JJ, Ou, JJ, Gao, W, Bhandari, J, Graham, D, Dudleenamjil, E, Babish, JG
Journal of medicinal food. 2019;(5):479-489
Abstract
Among the comorbidities of high body mass index, cardiovascular disease continued to be the leading cause of death and disability globally in 2015, while type 2 diabetes remained second. The primary objectives of this observational study were to confirm the safety, tolerability, and efficacy of our calorie-restricted Mediterranean diet with targeted dietary supplementation (PROG1) using globally recognized dietary supplementation. Fifty healthy overweight and obese subjects with cardiometabolic risk factors were assigned a modified Mediterranean diet, including protein shakes and targeted supplementation (PROG2), providing ∼68-76% of subject estimated calorie requirements. Salivary nitrite was assessed weekly and key cardiometabolic metrics were recorded at baseline and weeks 9 and 13. PROG2 was well tolerated with 86% compliance. The most common adverse effects were bloating, flatulence, and constipation, which were self-limiting. Subjects exhibited decreases (P < .01) from baseline of 12% in body weight, 18% in body fat, and 8.8% in waist circumference. Total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and triglycerides (TG) were reduced (P < .01), respectively, 19%, 22%, and 40%. Lipid ratios of TC/high-density lipoprotein (HDL), TG/HDL, and oxidized LDL (oxLDL)/HDL were decreased 15% (P < .01), 35% (P < .01), and 13% (P < .05), respectively. Inflammation biomarkers, oxLDL and high-sensitivity C-reactive protein, were reduced 17% (P < .01) and 30% (P < .05), respectively. Reductions of 9.0% for systolic (P < .01) and 12% (P < .01) for diastolic blood pressure were noted. In concert, the nitrogen dioxide salivary biomarker for nitric oxide was increased relative to baseline. PROG2 produced a dramatic 50% reduction in subjects meeting cardiometabolic syndrome criteria and a 38% decrease in Framingham 10-year cardiovascular risk. These results confirmed our previous findings that the addition of targeted nutraceutical supplementation to a calorie-restricted Mediterranean diet with lifestyle modifications improves multiple longevity risk factors more effectively than diet and lifestyle modification alone.