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Brain Hemodynamic Intermediate Phenotype Links Vitamin B12 to Cognitive Profile of Healthy and Mild Cognitive Impaired Subjects.
Cecchetti, L, Lettieri, G, Handjaras, G, Leo, A, Ricciardi, E, Pietrini, P, Pellegrini, S, ,
Neural plasticity. 2019;:6874805
Abstract
Vitamin B12, folate, and homocysteine are implicated in pivotal neurodegenerative mechanisms and partake in elders' mental decline. Findings on the association between vitamin-related biochemistry and cognitive abilities suggest that the structural and functional properties of the brain may represent an intermediate biomarker linking vitamin concentrations to cognition. Despite this, no previous study directly investigated whether vitamin B12, folate, and homocysteine levels are sufficient to explain individual neuropsychological profiles or, alternatively, whether the activity of brain regions modulated by these compounds better predicts cognition in elders. Here, we measured the relationship between vitamin blood concentrations, scores at seventeen neuropsychological tests, and brain activity of sixty-five elders spanning from normal to Mild Cognitive Impairment. We then evaluated whether task-related brain responses represent an intermediate phenotype, providing a better prediction of subjects' neuropsychological scores, as compared to the one obtained considering blood biochemistry only. We found that the hemodynamic activity of the right dorsal anterior cingulate cortex was positively associated (p value < 0.05 cluster corrected) with vitamin B12 concentrations, suggesting that elders with higher B12 levels had a more pronounced recruitment of this salience network region. Crucially, the activity of this area significantly predicted subjects' visual search and attention abilities (p value = 0.0023), whereas B12 levels per se failed to do so. Our results demonstrate that the relationship between blood biochemistry and elders' cognitive abilities is revealed when brain activity is included into the equation, thus highlighting the role of brain imaging as intermediate phenotype.
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Angiotensin Receptor Neprilysin Inhibitor for Functional Mitral Regurgitation.
Kang, DH, Park, SJ, Shin, SH, Hong, GR, Lee, S, Kim, MS, Yun, SC, Song, JM, Park, SW, Kim, JJ
Circulation. 2019;(11):1354-1365
Abstract
BACKGROUND The morbidity and mortality of patients with functional mitral regurgitation (MR) remain high, but no pharmacological therapy has been proven effective. The hypothesis of this study was that sacubitril/valsartan would be superior to valsartan alone in improving functional MR via dual inhibition of the renin-angiotensin system and neprilysin. METHODS In this double-blind trial, we randomly assigned 118 patients with heart failure with chronic functional MR secondary to left ventricular (LV) dysfunction to receive either sacubitril/valsartan or valsartan, in addition to standard medical therapy for heart failure. The primary end point was the change in effective regurgitant orifice area of functional MR from baseline to the 12-month follow-up. Secondary end points included changes in regurgitant volume, LV end-systolic volume, LV end-diastolic volume, and incomplete mitral leaflet closure area. RESULTS The decrease in effective regurgitant orifice area was significantly greater in the sacubitril/valsartan group than in the valsartan group (-0.058±0.095 versus -0.018±0.105 cm2; P=0.032) in an intention-to-treat analysis including 117 (99%) patients. Regurgitant volume was also significantly decreased in the sacubitril/valsartan group in comparison with the valsartan group (mean difference, -7.3 mL; 95% CI, -12.6 to -1.9; P=0.009). There were no significant between-group differences regarding the changes in incomplete mitral leaflet closure area and LV volumes, with the exception of LV end-diastolic volume index ( P=0.044). We noted no significant difference in the change of blood pressure between the treatment groups, and 7 patients (12%) in the sacubitril/valsartan group and 9 (16%) in the valsartan group had ≥1 serious adverse events ( P=0.54). CONCLUSIONS Among patients with secondary functional MR, sacubitril/valsartan reduced MR to a greater extent than did valsartan. Our findings suggest that an angiotensin receptor-neprilysin inhibitor might be considered for optimal medical therapy of patients with heart failure and functional MR. CLINICAL TRIAL REGISTRATION URL: https://www.clinicaltrials.gov . Unique identifier: NCT02687932.
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Brain energetics plays a key role in the coordination of electrophysiology, metabolism and hemodynamics: Evidence from an integrated computational model.
Capo Rangel, G, Prezioso, J, Gerardo-Giorda, L, Somersalo, E, Calvetti, D
Journal of theoretical biology. 2019;:26-39
Abstract
The energetic needs of brain cells at rest and during elevated neuronal activation has been the topic of many investigations where mathematical models have played a significant role providing a context for the interpretation of experimental findings. A recently proposed mathematical model, comprising a double feedback between cellular metabolism and electrophysiology, sheds light on the interconnections between the electrophysiological details associated with changes in the frequency of neuronal firing and the corresponding metabolic activity. We propose a new extended mathematical model comprising a three-way feedback connecting metabolism, electrophysiology and hemodynamics. Upon specifying the time intervals of higher neuronal activation, the model generates a potassium based signal leading to the concomitant increase in cerebral blood flow with associated vasodilation and metabolic changes needed to sustain the increased energy demand. The predictions of the model are in good qualitative and quantitative agreement with experimental findings reported in the literature, even predicting a slow after-hyperpolarization of a duration of approximately 16 s matching experimental observations.
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APOE gene-dependent BOLD responses to a breath-hold across the adult lifespan.
Rasmussen, PM, Aamand, R, Weitzberg, E, Christiansen, M, Østergaard, L, Lund, TE
NeuroImage. Clinical. 2019;:101955
Abstract
Age and apolipoprotein E (APOE) e4 genotype are two of the strongest known risk factors for sporadic Alzheimer's disease (AD). Neuroimaging has shown hemodynamic response changes with age, in asymptomatic carriers of the APOE e4 allele, and in AD. In this study, we aimed to characterize and differentiate age- and APOE gene-specific hemodynamic changes to breath-hold and visual stimulation. A further aim was to study whether these responses were modulated by 3-day intake of nitrate, a nitric oxide (NO) source. The study was designed as a randomized, double-blinded, placebo-controlled crossover study, and the study cohort comprised 41 APOE e4 carriers (e3/e4 or e4/e4 genotype) and 40 non-carriers (e3/e3 genotype) aged 30-70 years at enrollment. The participants underwent two scanning sessions, each preceded by ingestion of sodium nitrate or sodium chloride (control). During functional magnetic resonance imaging (fMRI) sessions, participants performed two concurrent tasks; a breath-hold task to probe cerebrovascular reactivity and a visual stimulation task to evoke functional hyperemia, respectively. We found that the blood oxygenation level dependent (BOLD) hemodynamic response to breath-hold was altered in APOE e4 carriers relative to non-carriers. Mid-aged (50-60 years of age) e4 carriers exhibited a significantly increased peak time relative to mid-aged e3 carriers, and peak time for younger (30-40 years of age) e4 carriers was significantly shorter than that of mid-aged e4 carriers. The response width was significantly increased for e4 carriers. The response peak magnitude significantly decreased with age. For the visual stimulation task, we found age-related changes, with reduced response magnitude with age but no significant effect of APOE allele type. We found no effect of nitrate ingestion on BOLD responses evoked by the breath-hold and visual stimulation tasks. The APOE gene-dependent response to breath-hold may reflect NO-independent differences in vascular function.
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5.
Cardiorenal Syndrome and Heart Failure-Challenges and Opportunities.
Yogasundaram, H, Chappell, MC, Braam, B, Oudit, GY
The Canadian journal of cardiology. 2019;(9):1208-1219
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Abstract
Cardiorenal syndromes (CRS) describe concomitant bidirectional dysfunction of the heart and kidneys in which 1 organ initiates, perpetuates, and/or accelerates decline of the other. CRS are common in heart failure and universally portend worsened prognosis. Despite this heavy disease burden, the appropriate diagnosis and classification of CRS remains problematic. In addition to the hemodynamic drivers of decreased renal perfusion and increased renal vein pressure, induction of the renin-angiotensin-aldosterone system, stimulation of the sympathetic nervous system, disruption of balance between nitric oxide and reactive oxygen species, and inflammation are implicated in the pathogenesis of CRS. Medical therapy of heart failure including renin-angiotensin-aldosterone system inhibition and β-adrenergic blockade can blunt these deleterious processes. Renovascular disease can accelerate the progression of CRS. Volume overload and diuretic resistance are common and complicate the management of CRS. In heart failure and CRS being treated with diuretics, worsening creatinine is not associated with worsened outcome if clinical decongestion is achieved. Adjunctive therapy is often required in the management of volume overload in CRS, but evidence for these therapies is limited. Anemia and iron deficiency are importantly associated with CRS and might amplify decline of cardiac and renal function. End-stage cardiac and/or renal disease represents an especially poor prognosis with limited therapeutic options. Overall, worsening renal function is associated with significantly increased mortality. Despite progress in the area of CRS, there are still multiple pathophysiological and clinical aspects of CRS that need further research to eventually develop effective therapeutic options.
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Hemodynamic Effects of Weight Loss in Obesity: A Systematic Review and Meta-Analysis.
Reddy, YNV, Anantha-Narayanan, M, Obokata, M, Koepp, KE, Erwin, P, Carter, RE, Borlaug, BA
JACC. Heart failure. 2019;(8):678-687
Abstract
OBJECTIVES The authors aimed to explore whether weight loss may improve central hemodynamics in obesity. BACKGROUND Hemodynamic abnormalities in obese heart failure with preserved ejection fraction patients are correlated with the amount of excess body mass, suggesting a possible causal relationship. METHODS Relevant databases were systematically searched from inception to May 2018, without language restriction. Studies reporting invasive hemodynamic measures before and following therapeutic weight loss interventions in patients with obesity but no clinically overt heart failure were extracted. RESULTS A total of 9 studies were identified, providing data for 110 patients. Six studies tested dietary intervention and 3 studies tested bariatric surgery. Over a median duration of 9.7 months (range 0.75 to 23.0 months), a median weight loss of 43 kg (range 10 to 58 kg) was associated with significant reductions in heart rate (-9 beats/min, 95% confidence interval [CI]: -12 to -6; p < 0.001), mean arterial pressure (-7 mm Hg, 95% CI: -11 to -3; p < 0.001), and resting oxygen consumption (-85 ml/min, 95% CI: -111 to -60; p < 0.001). Central cardiac hemodynamics improved, manifested by reductions in pulmonary capillary wedge pressure (-3 mm Hg, 95% CI: -5 to -1; p < 0.001) and mean pulmonary artery pressure (-5 mm Hg, 95% CI: -8 to -2; p = 0.001). Exercise hemodynamics were assessed in a subset of patients (n = 49) in which there was significant reduction in exercise pulmonary artery pressure (p = 0.02). CONCLUSIONS Therapeutic weight loss in obese patients without HF is associated with favorable hemodynamic effects. Randomized controlled trials evaluating strategies for weight loss in obese patients with heart failure such as the obese phenotype of heart failure with preserved ejection fraction are needed.
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A review of the mechanism of action, metabolic profile and haemodynamic effects of sodium-glucose co-transporter-2 inhibitors.
Brown, E, Rajeev, SP, Cuthbertson, DJ, Wilding, JPH
Diabetes, obesity & metabolism. 2019;:9-18
Abstract
Inhibition of glucose transport in the kidney, to produce glucosuria and thus directly lower blood glucose seems a remarkably simple way to treat diabetes (type 1 or type 2). The development of sodium-glucose co-transporter-2 (SGLT2) inhibitors and their subsequent clinical development has on one hand shown this to be true, but at another level has helped reveal a complex web of interacting effects starting in the kidney and modulating multiple metabolic pathways in a variety of other organs. These underlie the now clear benefits of this class of drugs in the management of type 2 diabetes from glucose lowering, weight loss and blood pressure reduction through to the reductions in cardiovascular and renal complications observed in long-term outcomes trials. They also explain some of the adverse effects that have emerged, including the risk of diabetic ketoacidosis. This review describes the effects of SGLT2 inhibition in relation to this complex physiology, and shows how this can favourably alter the pathophysiology of type 2 diabetes.
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Pharmacokinetic and haemodynamic interactions between amlodipine and losartan in human beings.
Park, JW, Kim, KA, Il Kim, Y, Park, JY
Basic & clinical pharmacology & toxicology. 2019;(4):345-352
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Abstract
The combination of calcium channel blockers (CCB) and angiotensin receptor blockers (ARB) for the treatment of hypertension showed improved efficacy and safety. Amlodipine is mainly metabolized by cytochrome P450 (CYP) 3A4, whereas losartan is metabolized by CYP2C9 and CYP3A4. The potential pharmacokinetic interactions between amlodipine and losartan were assessed. An open-label, three-period, fixed-sequence trial was conducted. Amlodipine, losartan and combined amlodipine and losartan were administered to 24 healthy male participants during periods 1, 2 and 3, respectively, for 9 days each. The pharmacokinetics of amlodipine, losartan and EXP-3174, an active metabolite of losartan, were assessed at steady-state. Twenty participants completed the study without serious adverse events. Losartan did not influence the exposure of amlodipine at steady-state (AUCτ , 165.15 ng h/mL [amlodipine alone] vs 172.36 ng h/mL [combination], P = 0.389) [geometric mean ratio (GMR) (90% confidence interval [CI]), 1.060 (0.954-1.178)]. In addition, the exposure of EXP-3174 was not affected by amlodipine (AUCτ , 1159.46 ng h/mL vs 1105.10 ng h/mL, P = 0.295) (GMR [90% CI], 0.957 [0.891-1.027]). However, amlodipine significantly decreased the exposure of losartan at steady-state (AUCτ , 1241.50 ng h/mL vs 1082.02 ng h/mL, P = 0.006) (GMR [90% CI], 0.875 [0.813-0.942]) and increased oral clearance of losartan (84.65 L/h vs 97.26 L/h, P = 0.002). Combination use of two drugs caused additive haemodynamic changes compared to treatment of amlodipine or losartan alone. The co-administration of amlodipine and losartan was tolerable and did not cause substantial pharmacokinetic interaction, even though losartan disposition was affected. Combination use of the two drugs caused additive haemodynamic changes compared to monotherapy of amlodipine or losartan.
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20% Human Albumin Solution Fluid Bolus Administration Therapy in Patients After Cardiac Surgery (the HAS FLAIR Study).
Wigmore, GJ, Anstey, JR, St John, A, Greaney, J, Morales-Codina, M, Presneill, JJ, Deane, AM, MacIsaac, CM, Bailey, M, Tatoulis, J, et al
Journal of cardiothoracic and vascular anesthesia. 2019;(11):2920-2927
Abstract
OBJECTIVE To compare the effects of fluid bolus therapy using 20% albumin versus crystalloid on fluid balance, hemodynamic parameters, and intensive care unit (ICU) treatment effects in post-cardiac surgery patients. DESIGN Sequential period open-label pilot study. SETTING University teaching hospital. PARTICIPANTS One hundred adult cardiac surgery patients who were prescribed fluid bolus therapy to correct hypotension or perceived hypovolemia or to optimize cardiac index during the first 24 hours in the ICU. INTERVENTIONS The first 50 patients were treated with crystalloid fluid bolus therapy in the first period (control), and 50 patients with up to 2 treatments of 100 mL of 20% albumin fluid bolus therapy in the second period (intervention), followed by crystalloid therapy if needed. MEASUREMENTS AND MAIN RESULTS Demographic characteristics were similar at baseline. The intervention was associated with a less positive median fluid balance in the first 24 hours (albumin: 1,100 [650-1,960] v crystalloid: 1,970 [1,430-2,550] p = 0.001), fewer episodes of fluid bolus therapy (3 [2-5] v 5 [4-7]; p < 0.0001) and a lesser volume of fluid bolus therapy (700 [200-1,450] v 1,500 mL/24 h [1,100-2,250]; p < 0.0001). The intervention also was associated with a decreased median overall dose of norepinephrine in the first 24 hours of ICU stay (19 [0-52] v 47 µg/kg/24 hours [0-134]; p = 0.025) and shorter median time to cessation of norepinephrine (17 [5-28] v 28 hours [20-48]; p = 0.002). CONCLUSION Post-cardiac surgery fluid bolus therapy with 20% albumin when compared with crystalloid fluid resulted in less positive fluid balance as well as several hemodynamic and potential ICU treatment advantages.
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Risk Factor Variability and Cardiovascular Outcome: JACC Review Topic of the Week.
Messerli, FH, Hofstetter, L, Rimoldi, SF, Rexhaj, E, Bangalore, S
Journal of the American College of Cardiology. 2019;(20):2596-2603
Abstract
Until recently, intraindividual visit-to-visit variability of cardiovascular risk factors has been dismissed as random fluctuation. This simplistic concept was challenged by demonstrating that visit-to-visit blood pressure variability, independent of average blood pressure, was a powerful risk factor for stroke. Subsequently, variability of other cardiovascular risk factors such as cholesterol, glycemia, and body weight was documented to increase risk independent of their absolute values. Variability of these risk factors has been demonstrated to be a powerful predictor for all-cause and cardiovascular mortality, stroke, coronary artery disease, heart failure, end-stage renal disease, and dementia. With the notable exception of heart rate, cardiovascular risk factors must now be defined by 2 components: the magnitude and duration of sustained risk factor elevation and, equally important, the variability of the same risk factor over time.