Changes In Oxygen Consumption Research Articles

Increased Retinal Metabolism Induced by Flicker in the Isolated Mouse Retina.

Both the retina and brain exhibit neurovascular coupling, increased blood flow during increased neural activity. In the retina increased blood flow can be evoked by flickering light, but the magnitude of the metabolic change that underlies this is not known. Local changes in oxygen consumption (QO2) are difficult to measure in vivo when both supply and demand are changing. Here we isolated the C57BL/6J mouse retina and supplied it with oxygen from both sides of the tissue. Microelectrode recordings of PO2 were made in darkness and during 20 s of high scotopic flickering light at 1 Hz. Flicker led to a PO2 increase in the outer retina and a decrease in the inner retina, indicating that outer retinal QO2 (QOR) decreased and inner retinal QO2 (QIR) increased. A four-layer oxygen diffusion model was fitted to PO2 values obtained in darkness and at the end of flicker to determine the values of QOR and QIR. QOR in flicker was 76 ± 14% (mean and SD, n = 10) of QOR in darkness. The increase in QIR was smaller, 6.4 ± 5.0%. These metabolic changes are likely smaller than the maximum changes, because with no regeneration of pigment in the isolated retina, we limited the illumination. Further modeling indicated that at high illumination, QIR could increase by up to 45%, which is comparable to the magnitude of flow changes. This suggests that the blood flow increase is at least roughly matched to the increased metabolic demands of activity in the retina.

Correlates of Plasma NT-proBNP/Cyclic GMP Ratio in Heart Failure With Preserved Ejection Fraction: An Analysis of the RELAX Trial.

Phosphodiesterases degrade cyclic GMP (cGMP), the second messenger that mediates the cardioprotective effects of natriuretic peptides. High natriuretic peptide/cGMP ratio may reflect, in part, phosphodiesterase activity. Correlates of natriuretic peptide/cGMP in patients with heart failure with preserved ejection fraction are not well understood. Among patients with heart failure with preserved ejection fraction in the RELAX (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in Heart Failure With Preserved Ejection Fraction) trial, we examined (1) cross-sectional correlates of circulating NT-proBNP (N-terminal pro-B-type natriuretic peptide)/cGMP ratio, (2) whether selective phosphodiesterase-5 inhibition by sildenafil changed the ratio, and (3) whether the effect of sildenafil on 24-week outcomes varied by baseline ratio. In 212 subjects, NT-proBNP/cGMP ratio was calculated at randomization and 24 weeks. Correlates of the ratio and its change were examined in multivariable proportional odds models. Whether baseline ratio modified the sildenafil effect on outcomes was examined by interaction terms. Higher NT-proBNP/cGMP ratio was associated with greater left ventricular mass and troponin, the presence of atrial fibrillation, and lower estimated glomerular filtration rate and peak oxygen consumption. Compared with placebo, sildenafil did not alter the ratio from baseline to 24 weeks (P=0.17). The effect of sildenafil on 24-week change in peak oxygen consumption, left ventricular mass, or clinical composite outcome was not modified by baseline NT-proBNP/cGMP ratio (P-interaction >0.30 for all). Among patients with heart failure with preserved ejection fraction, higher NT-proBNP/cGMP ratio associated with an adverse cardiorenal phenotype, which was not improved by selective phosphodiesterase-5 inhibition. Other phosphodiesterases may be greater contributors than phosphodiesterase-5 to the adverse phenotype associated with a high natriuretic peptide/cGMP ratio in HFpEF. clinicaltrials.gov. Identifier: NCT00763867.

Differential changes in blood flow and oxygen utilization in active muscles between voluntary exercise and electrical muscle stimulation in young adults.

The physiological effects on blood flow and oxygen utilization in active muscles during and after involuntary contraction triggered by electrical muscle stimulation (EMS) remain unclear, particularly compared with those elicited by voluntary (VOL) contractions. Therefore, we used diffuse correlation and near-infrared spectroscopy (DCS-NIRS) to compare changes in local muscle blood flow and oxygen consumption during and after these two types of muscle contractions in humans. Overall, 24 healthy young adults participated in the study, and data were successfully obtained from 17 of them. Intermittent (2-s contraction, 2-s relaxation) isometric ankle dorsiflexion with a target tension of 20% of maximal VOL contraction was performed by EMS or VOL for 2 min, followed by a 6-min recovery period. DCS-NIRS probes were placed on the tibialis anterior muscle, and relative changes in local tissue blood flow index (rBFI), oxygen extraction fraction (rOEF), and metabolic rate of oxygen (rMRO2) were continuously derived. EMS induced more significant increases in rOEF and rMRO2 than VOL exercise but a comparable increase in rBFI. After EMS, rBFI and rMRO2 decreased more slowly than after VOL and remained significantly higher until the end of the recovery period. We concluded that EMS augments oxygen consumption in contracting muscles by enhancing oxygen extraction while increasing oxygen delivery at a rate similar to the VOL exercise. Under the conditions examined in this study, EMS demonstrated a more pronounced and/or prolonged enhancement in local muscle perfusion and aerobic metabolism compared with VOL exercise in healthy participants.NEW & NOTEWORTHY This is the first study to visualize continuous changes in blood flow and oxygen utilization within contracted muscles during and after electrical muscle stimulation (EMS) using combined diffuse correlation and near-infrared spectroscopy. We found that initiating EMS increases blood flow at a rate comparable to that during voluntary (VOL) exercise but enhances oxygen extraction, resulting in higher oxygen consumption. Furthermore, EMS increased postexercise muscle perfusion and oxygen consumption compared with that after VOL exercise.

Differential Mitochondrial, Oxidative Stress and Inflammatory Responses to SARS-CoV-2 Spike Protein Receptor Binding Domain in Human Lung Microvascular, Coronary Artery Endothelial and Bronchial Epithelial Cells.

Recent evidence indicates that the SARS-CoV-2 spike protein affects mitochondria with a cell type-dependent outcome. We elucidate the effect of the SARS-CoV-2 receptor binding domain (RBD) on the mitochondrial network and cristae morphology, oxygen consumption, mitoROS production, and inflammatory cytokine expression in cultured human lung microvascular (HLMVECs), coronary artery endothelial (HCAECs), and bronchial epithelial cells (HBECs). Live Mito Orange staining, STED microscopy, and Fiji MiNa analysis were used for mitochondrial cristae and network morphometry; an Agilent XFp analyser for mitochondrial/glycolytic activity; MitoSOX fluorescence for mitochondrial ROS; and qRT-PCR plus Luminex for cytokines. HLMVEC exposure to SARS-CoV-2 RBD resulted in the fragmentation of the mitochondrial network, mitochondrial swelling, increased cristae area, reduced cristae density, and suppressed mitochondrial oxygen consumption and glycolysis. No significant mitochondrial morphology or oxygen consumption changes were observed in HCAECs and HBECs. SARS-CoV-2 RBD induced mitoROS-mediated expression of cytokines GM-CSF and IL-1β in all three investigated cell types, along with IL-8 expression in both endothelial cell types. The findings suggest mitochondrial ROS control SARS-CoV-2 RBD-induced inflammation in HLMVECs, HCAECs, and HBECs, with the mitochondria of HLMVECs being more sensitive to SARS-CoV-2 RBD.

Individual aerodynamic and physiological data are critical to optimise cycling time trial performance: one size does not fit all

Cycling time trials are characterised by riders adopting positions to lessen the impact of aerodynamic drag. Aerodynamic positions likely impact the power a rider is able to produce due to changes in oxygen consumption, blood flow, muscle activation and economy. Therefore, the gain from optimising aerodynamics must outweigh the potential physiological cost. The aim was to establish the relationship between energy expenditure and aerodynamic drag, with a secondary aim to determine the reliability of a commercially available handlebar mounted aero device for measuring aerodynamic drag. Nine trained male cyclists volunteered for the study. They completed 4 × 3200 m on an outdoor velodrome where stack height was adjusted in 1 cm integers. The drag coefficient (CdA), oxygen consumption and aerodynamic-physiological economy (APE) were determined at each stack height, with data used to model 40 km TT performance. Small to moderate effect sizes (ES) in response to stack height change were found for CdA, APE and energy cost. The change in TT time was correlated to ∆aerodynamic drag and ∆APE. Meaningful impacts of change in stack height on CdA, APE, energy cost and predicted TT performance, are apparent with highly individualised responses to positional changes.

The Impact of Exercise-Induced Muscle Damage on Various Cycling Performance Metrics: A Systematic Review and Meta-Analysis.

Devantier-Thomas, B, Deakin, GB, Crowther, F, Schumann, M, and Doma, K. The impact of exercise-induced muscle damage on various cycling performance metrics: a systematic review and meta-analysis. J Strength Cond Res 38(1): 196-212, 2024-This systematic review and meta-analysis examined the impact of exercise-induced muscle damage (EIMD) on cycling performance. The primary outcome measure was cycling performance, whereas secondary outcome measures included creatine kinase (CK), delayed-onset muscle soreness (DOMS), and muscular contractions. Data were extracted and quantified through forest plots to report on the standardized mean difference and p values. The meta-analysis showed no significant change in oxygen consumption at 24-48 hours (p > 0.05) after the muscle damage protocol, although ventilation and rating of perceived exertion significantly increased (p < 0.05) during submaximal cycling protocols. Peak power output during both sprint and incremental cycling performance was significantly reduced (p < 0.05), but time-trial and distance-trial performance showed no change (p > 0.05). Measures of CK and DOMS were significantly increased (p < 0.05), whereas muscular force was significantly reduced following the muscle-damaging protocols (p < 0.05), confirming that cycling performance was assessed during periods of EIMD. This systematic review showed that EIMD affected both maximal and submaximal cycling performance. Therefore, coaches should consider the effect of EIMD on cycling performance when implementing unaccustomed exercise into a cycling program. Careful consideration should be taken to ensure that additional training does not impair performance and endurance adaptation.

The influence of carbon dioxide on cerebral metabolism and oxygen consumption: combining multimodal monitoring with dynamic systems modelling.

Hypercapnia increases cerebral blood flow. The effects on cerebral metabolism remain incompletely understood although studies show an oxidation of cytochrome c oxidase, Complex IV of the mitochondrial respiratory chain. Systems modelling was combined with previously published non-invasive measurements of cerebral tissue oxygenation, cerebral blood flow, and cytochrome c oxidase redox state to evaluate any metabolic effects of hypercapnia. Cerebral tissue oxygen saturation and cytochrome oxidase redox state were measured with broadband near infrared spectroscopy and cerebral blood flow velocity with transcranial Doppler ultrasound. Data collected during 5-min hypercapnia in awake human volunteers were analysed using a Fick model to determine changes in brain oxygen consumption and a mathematical model of cerebral hemodynamics and metabolism (BrainSignals) to inform on mechanisms. Either a decrease in metabolic substrate supply or an increase in metabolic demand modelled the cytochrome oxidation in hypercapnia. However, only the decrease in substrate supply explained both the enzyme redox state changes and the Fick-calculated drop in brain oxygen consumption. These modelled outputs are consistent with previous reports of CO2 inhibition of mitochondrial succinate dehydrogenase and isocitrate dehydrogenase. Hypercapnia may have physiologically significant effects suppressing oxidative metabolism in humans and perturbing mitochondrial signalling pathways in health and disease.

Microphysiological pancreas-on-chip platform with integrated sensors to model endocrine function and metabolism.

Pancreatic in vitro research is of major importance to advance mechanistic understanding and development of treatment options for diseases such as diabetes mellitus. We present a thermoplastic-based microphysiological system aiming to model the complex microphysiological structure and function of the endocrine pancreas with concurrent real-time read-out capabilities. The specifically tailored platform enables self-guided trapping of single islets at defined locations: β-cells are assembled to pseudo-islets and injected into the tissue chamber using hydrostatic pressure-driven flow. The pseudo-islets can further be embedded in an ECM-like hydrogel mimicking the native microenvironment of pancreatic islets in vivo. Non-invasive real-time monitoring of the oxygen levels on-chip is realized by the integration of luminescence-based optical sensors to the platform. To monitor insulin secretion kinetics in response to glucose stimulation in a time-resolved manner, an automated cycling of different glucose conditions is implemented. The model's response to glucose stimulation can be monitored via offline analysis of insulin secretion and via specific changes in oxygen consumption due to higher metabolic activity of pseudo-islets at high glucose levels. To demonstrate applicability for drug testing, the effects of antidiabetic medications are assessed and changes in dynamic insulin secretion are observed in line with the respective mechanism of action. Finally, by integrating human pancreatic islet microtissues, we highlight the flexibility of the platform and demonstrate the preservation of long-term functionality of human endocrine pancreatic tissue.

A Pilot Randomized Trial of Combined Cognitive-Behavioral Therapy and Exercise Training Versus Exercise Training Alone for the Management of Chronic Insomnia in Obstructive Sleep Apnea.

Insomnia treatment among individuals with comorbid insomnia and obstructive sleep apnea is suboptimal. In a pilot randomized controlled trial, 19 individuals with comorbid insomnia and obstructive sleep apnea were allocated to one of two arms: EX + EX, consisting of two 8-week phases of exercise training (EX), or RE + CBTiEX, encompassing 8weeks of relaxation training (RE) followed by 8weeks of combined cognitive-behavioral therapy and exercise(CBTiEX). Outcomes included Insomnia Severity Index (ISI), polysomnography, and cardiorespiratory fitness measures. A mixed-model analysis of variance revealed a Group × Time interaction on peak oxygen consumption change, F(1, 14) = 10.1, p = .007, and EX increased peak oxygen consumption (p = .03, g' = -0.41) and reduced ISI (p = .001, g' = 0.82) compared with RE (p = .49, g = 0.16) post-8weeks. Post-16weeks, there was a significant Group × Time interaction (p = .014) driven by RE + CBTiEX yielding a larger improvement in ISI (p = .023, g' = 1.48) than EX + EX (p = .88, g' < 0.1). Objective sleep was unchanged. This study showed promising effects of regular EX alone and combined with cognitive-behavioral therapy for insomnia on ISI in comorbid insomnia and obstructive sleep apnea.

Biologically derived epicardial patch induces macrophage mediated pathophysiologic repair in chronically infarcted swine hearts

There are nearly 65 million people with chronic heart failure (CHF) globally, with no treatment directed at the pathologic cause of the disease, the loss of functioning cardiomyocytes. We have an allogeneic cardiac patch comprised of cardiomyocytes and human fibroblasts on a bioresorbable matrix. This patch increases blood flow to the damaged heart and improves left ventricular (LV) function in an immune competent rat model of ischemic CHF. After 6 months of treatment in an immune competent Yucatan mini swine ischemic CHF model, this patch restores LV contractility without constrictive physiology, partially reversing maladaptive LV and right ventricular remodeling, increases exercise tolerance, without inducing any cardiac arrhythmias or a change in myocardial oxygen consumption. Digital spatial profiling in mice with patch placement 3 weeks after a myocardial infarction shows that the patch induces a CD45pos immune cell response that results in an infiltration of dendritic cells and macrophages with high expression of macrophages polarization to the anti-inflammatory reparative M2 phenotype. Leveraging the host native immune system allows for the potential use of immunomodulatory therapies for treatment of chronic inflammatory diseases not limited to ischemic CHF.

Peripheral muscle fractional tissue oxygen extraction in stable term and preterm neonates during the first 24 h after birth.

Peripheral muscle fractional tissue oxygen extraction (pFTOE) represents the relative extraction of oxygen from the arterial to venous compartment, providing information about dynamic changes of oxygen delivery and oxygen consumption. The aim of the present study was to establish reference values of pFTOE during the first 24 h after birth in stable term and late preterm neonates. The present study is a post-hoc analysis of secondary outcome parameters of prospective observational studies. Only stable neonates without infection, asphyxia and any medical support were eligible for our analysis to obtain normal values. For measurements of peripheral muscle tissue oxygenation index (pTOI) during the first 24 h after birth in term and preterm neonates, the NIRO200/NIRO200NX was used. Arterial oxygen saturation (SpO2) was obtained by pulse oximetry. pFTOE was calculated out of pTOI and SpO2: pFTOE = (SpO2-pTOI)/SpO2. Measurements of neonates were stratified into four groups according to their respective measurement time point (6 h periods) after birth. Term and preterm neonates were analyzed separately. Mean values of measurements during the first time period (0-6 h after birth) were compared to measurements of the following time periods (second = 7-12 h, third = 13-18 h, fourth = 19-24 h after birth). Two-hundred-fourty neonates (55 term and 185 late preterm neonates) had at least one peripheral muscle NIRS measurements within the first 24 h after birth. Mean gestational age and birth weight were 39.4 ± 1.1 weeks and 3360 (2860-3680)g in term neonates and 34.0 ± 1.4 weeks and 2060 (1750-2350)g in preterm neonates, respectively. In term neonates pFTOE was 0.264 (0.229-0.300), 0.228 (0.192-0.264), 0.237 (0.200-0.274) and 0.220 (0.186-0.254) in the first, second, third and fourth time period. In preterm neonates pFTOE was 0.229 (0.213-0.246), 0.225 (0.209-0.240), 0.226 (0.210-0.242) and 0.238 (0.222-0.255) in the first, second, third and fourth time period. pFTOE did not show any significant changes between the time periods, neither in term nor in preterm neonates. We provide reference values of pFTOE for stable term and late preterm neonates within the first 24 h after birth, which were stable when comparing four 6-h periods. These normal values are of great need for interpreting pFTOE in scientific context as well as for potential future clinical applications.

Effect of Mavacamten in Women Compared With Men With Obstructive Hypertrophic Cardiomyopathy: Insights From EXPLORER-HCM.

Compared with men, women with hypertrophic cardiomyopathy (HCM) have a higher incidence of heart failure and worse outcomes. We investigated baseline clinical and echocardiographic characteristics and response to mavacamten among women compared with men in the EXPLORER-HCM study (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy). A prespecified post hoc analysis of sex from the blinded, randomized EXPLORER-HCM trial of mavacamten versus placebo in symptomatic patients with obstructive HCM was performed. Baseline characteristics were compared with t tests for continuous variables (expressed as mean values) and χ2 tests for categorical variables. Prespecified primary, secondary, and exploratory end points and echocardiographic measurements from baseline to end of treatment (week 30) were analyzed with ANCOVA for continuous end points and a generalized linear model with binomial distribution for binary end points, with adjustment for each outcome's baseline value, New York Heart Association class, β-blocker use, and ergometer type. At baseline, women (n=102) were older (62 years versus 56 years; P<0.0001), had lower peak oxygen consumption (16.7 mL·kg-1·min-1 versus 21.3 mL·kg-1·min-1; P<0.0001), were more likely to be assigned New York Heart Association class III (42% versus 17%; P<0.0001), had worse health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 64 versus 75; P<0.0001), and had higher baseline plasma NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels (1704 ng/L versus 990 ng/L; P=0.004) than men (n=149). After 30 weeks of mavacamten treatment, similar improvements were observed in women and men in the primary composite end point (percentage difference on mavacamten versus placebo, 22% versus 19%, respectively; P=0.759) and in the secondary end points of change in postexercise left ventricular outflow tract gradient (-42.4 mm Hg versus -33.6 mm Hg; P=0.348), change in peak oxygen consumption (1.2 mL·kg-1·min-1 versus 1.6 mL·kg-1·min-1; P=0.633), and percentage achieving ≥1 New York Heart Association class improvement (41% versus 28%; P=0.254). However, women had greater improvement in health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 14.8 versus 6.1; P=0.026) and in the exploratory end point of NT-proBNP levels (-1322 ng/L versus -649 ng/L; P=0.0008). Although at baseline women with symptomatic obstructive HCM enrolled in EXPLORER-HCM were older and had worse heart failure and health status than men, treatment with mavacamten resulted in similar improvements in the primary and most secondary EXPLORER-HCM end points and greater improvements in health status and NT-proBNP. URL: https://www.clinicaltrials.gov; Unique identifier: NCT03470545.

Differential response to interleukin-1 blockade with anakinra on cardiorespiratory fitness in patients with heart failure with preserved ejection fraction stratified according to ejection fraction

Abstract Background Patients with heart failure with preserved ejection fraction (HFpEF) are a heterogeneous clinical population and might respond differently to pharmacologic therapies based on their baseline left ventricular EF (LVEF) (50-59% vs. ≥60%). Interleukin-1 (IL-1) is a key pro-inflammatory cytokine being explored as a therapeutic target in HFpEF for its effects on numerous outcomes including cardiorespiratory fitness (CRF). Purpose Our aim was to examine changes in CRF and C-reactive protein (CRP), a surrogate for IL-1 activity, in patients with HFpEF treated with the IL-1 recombinant human receptor antagonist anakinra, stratified according to resting LVEF. Methods We analyzed data from 32 patients (median age 55 [51-64] years, 24 (75%) female) with HFpEF, defined as a presence of HF symptoms, LVEF≥50%, and evidence of left ventricular diastolic dysfunction or elevated filling pressures. All patients were treated with anakinra 100 mg subcutaneously daily for 12 [2-12] weeks. Patients were stratified into two groups: LVEF 50-59% and LVEF ≥60%. At baseline and during treatment, patients underwent cardiopulmonary exercise testing and venipuncture to measure changes in peak oxygen consumption (peak VO2) and CRP. Categorical and continuous variables are expressed as N (%) and median (interquartile range) and were compared with the chi-square and Mann-Whitney test, respectively. The within-group paired differences were compared using the Wilcoxon signed-rank test. Results The cohort included 15 patients with LVEF 50-59% and 17 with LVEF ≥60%, without significant differences in age and sex between groups. In patients with LVEF 50-59% and ≥60%, baseline peak VO2 was 14.1 [13.1–17.3] and 13.8 [11.8-18.6] mLO2·kg-1·min-1, respectively (p = 0.82), and CRP was 6.2 [3.4-15.9] and 6.1 [3.7-17.6] mg/L, respectively (p = 0.74). A significant increase in peak VO2 (from 13.8 [11.8-18.6] to 15.8 [12.7-19.9] mLO2·kg-1·min-1, p = 0.033) and decrease in CRP (from 6.2 [3.4-15.9] mg/L to 3.4 [1.0-6.7] mg/L, p = 0.003) was seen in patients with LVEF ≥60%; whereas in those with LVEF 50-59% there were no significant changes in peak VO2 (from 14.1 [13.1–17.3] to 14.1 [11.0–17.3] mLO2·kg-1·min-1, p = 0.25) despite a significant reduction in CRP (from 6.1 [3.7-17.6] mg/L to 1.4 [0.8-11.4] mg/L, p = 0.016). We found a difference in the interval changes in peak VO2 (0 [from -1.1 to +0.3] vs +1.7 [from -0.7 to +2.3] mLO2·kg-1·min-1 in patients with LVEF 50-59% and ≥60%, respectively, p = 0.01), without differences in the interval change in CRP levels (–3.5 [from -6 to -2.1] vs –3.0 [from -11.4 to -2.1] mg/L, respectively, p = 0.91). Figure 1. Conclusions Patients with HFpEF demonstrate differential peak VO2 response to anakinra treatment based on resting LVEF, with those with a LVEF ≥60% showing greater improvement in CRF. Further randomized control trials are needed to validate these data and explore the potential underlying mechanisms.

Sacubitril/valsartan for treatment of symptomatic non-obstructive hypertrophic cardiomyopathy: a randomised, controlled, phase II clinical trial (SILICOFCM)

Abstract Aim To evaluate the effect of sacubitril/valsartan on exercise capacity, cardiac structure, and function in patients with hypertrophic cardiomyopathy (HCM). Methods Phase II, randomised, open-label multicentre study enrolled adult patients with symptomatic non-obstructive HCM (NYHA class I–III) who were randomly assigned (2:1) to receive sacubitril/valsartan (target dose 97/103mg) or usual care for 16 weeks. Primary endpoint was a change in peak oxygen consumption (peak VO2). Secondary endpoints included echocardiography measures of cardiac structure and function, natriuretic peptides and other biomarkers, and Minnesota Living with Heart Failure quality of life (QoL). Results Between May 2018 and November 2021, 354 patients were screened for eligibility, 115 patients (mean age 58 years [SD 11], 37% women) met the study inclusion criteria and were randomly assigned to sacubitril/valsartan (N=79) or usual care (N=36). At 16 weeks, there was no significant change in peak VO2 from baseline in sacubitril/valsartan (15.3 [4.3] vs 15.9 [4.3] ml/kg/min, p=0.13), or usual care group (p=0.47). There was a significant reduction in ventilatory efficiency slope (30.1 [7] vs 28.4 [4.9], p=0.03), but not in the control group (p=0.09). No significant changes were found in systolic or diastolic function, cardiac structure, or plasma biomarkers. The QoL score decreased significantly in the sacubitril/valsartan by 6 points (p=0.005) but not in the usual care group (p=0.66). Conclusion In patients with hypertrophic cardiomyopathy, 16 weeks of treatment with sacubitril/valsartan was well tolerated and contributed to a significant improvement in ventilatory efficiency and quality of life but not in exercise capacity or cardiac function.

Effectiveness of hybrid comprehensive telerehabilitation in heart failure patients with permanent atrial fibrillation - subanalysis of the TELEREH-HF RCT

Abstract Background Atrial fibrillation (AF) negatively impacts physical fitness and quality of life (QoL). Little is known about efficacy of hybrid comprehensive telerehabilitation (HCTR) in heart failure (HF) patients with AF. Purpose The purpose of this study was to assess safety and effectiveness of HCTR in HF patients with permanent AF. Methods The present analysis formed part of TELEREH-HF multicenter, randomized trial that enrolled 850 HF patients (NYHA I-III, LVEF ≤ 40%). Patients were randomized 1:1 to HCTR plus usual care (UC) or UC alone. Patients underwent either an HCTR (1 week in hospital and 8 weeks at home, five times weekly) or UC with observation. The effectiveness of HCTR was assessed by changes in peak oxygen consumption (VO2 peak), workload duration (t) in cardiopulmonary exercise test and quality of life (QoL) based on Medical Outcome Survey Short Form 36 Questionnaire (SF-36). Measurements were made before and after intervention/observation. Results There were 73 patients with permanent AF in HCTR group and 72 patients with permanent AF in UC group. HCTR resulted in a significant improvement in VO2peak and workload duration. We did not observe these favorable results in the UC group. In the HCTR group, there was a significantly greater improvement in physical component of QoL than in the UC group. All results are presented in Table 1. In neither group were there deaths nor major adverse events. Conclusion In HF patients with permanent AF, hybrid comprehensive telerehabilitation is safe and resulted in a significant improvement in physical capacity and physical component of QoL.

A versatile pumpless multi-channel fluidics system for maintenance and real-time functional assessment of tissue and cells

To address the needs of the life sciences community and the pharmaceutical industry in pre-clinical drug development to both maintain and continuously assess tissue metabolism and function with simple and rapid systems, we improved on the initial BaroFuse to develop it into a fully functional, pumpless, scalable multi-channel fluidics instrument that continuously measures changes in oxygen consumption and other endpoints in response to test compounds. We and several other laboratories assessed it with a wide range of tissue types including retina, pancreatic islets, liver, and hypothalamus with both aqueous and gaseous test compounds. The setup time was less than an hour for all collaborating groups, and there was close agreement between data obtained from the different laboratories. This easy-to-use system reliably generates real-time metabolic and functional data from tissue and cells in response to test compounds that will address a critical need in basic and applied research.

Yerba Maté (Ilex paraguariensis) Supplement Exerts Beneficial, Tissue-Specific Effects on Mitochondrial Efficiency and Redox Status in Healthy Adult Mice.

Yerba maté, a herbal tea derived from Ilex paraguariensis, has previously been reported to be protective against obesity-related and other cardiometabolic disorders. Using high-resolution respirometry and reverse-phase high-performance liquid chromatography, the effects of four weeks of yerba maté consumption on mitochondrial efficiency and cellular redox status in skeletal muscle, adipose, and liver, tissues highly relevant to whole-body metabolism, were explored in healthy adult mice. Yerba maté treatment increased the mitochondrial oxygen consumption in adipose but not in the other examined tissues. Yerba maté increased the ATP concentration in skeletal muscle and decreased the ATP concentration in adipose. Combined with the observed changes in oxygen consumption, these data yielded a significantly higher ATP:O2, a measure of mitochondrial efficiency, in muscle and a significantly lower ATP:O2 in adipose, which was consistent with yerba maté-induced weight loss. Yerba maté treatment also altered the hepatic glutathione (GSH)/glutathione disulfide (GSSG) redox potential to a more reduced redox state, suggesting the treatment's potential protective effects against oxidative stress and for the preservation of cellular function. Together, these data indicate the beneficial, tissue-specific effects of yerba maté supplementation on mitochondrial bioenergetics and redox states in healthy mice that are protective against obesity.

Cardio-Oncology Rehabilitation for Cancer Survivors With High Cardiovascular Risk

Cardiovascular disease is a leading cause of morbidity in cancer survivors, which makes strategies aimed at mitigating cardiovascular risk a subject of major contemporary importance. To assess whether a center-based cardiac rehabilitation (CBCR) framework compared with usual care encompassing community-based exercise training (CBET) is superior for cardiorespiratory fitness improvement and cardiovascular risk factor control among cancer survivors with high cardiovascular risk. This prospective, single-center, randomized clinical trial (CORE trial) included adult cancer survivors who had exposure to cardiotoxic cancer treatment and/or previous cardiovascular disease. Enrollment took place from March 1, 2021, to March 31, 2022. End points were assessed at baseline and after the 8-week intervention. Participants were randomly assigned in a 1:1 ratio to 8 weeks of CBCR or CBET. The combined aerobic and resistance exercise sessions were performed twice a week. The powered primary efficacy measure was change in peak oxygen consumption (V̇o2) at 2 months. Secondary outcomes included handgrip maximal strength, functional performance, blood pressure (BP), body composition, body mass index (BMI; calculated as weight in kilograms divided by height in meters squared), lipid profile, plasma biomarker levels, physical activity (PA) levels, psychological distress, quality of life (QOL), and health literacy. A total of 75 participants completed the study (mean [SD] age, 53.6 [12.3] years; 58 [77.3%] female), with 38 in the CBCR group and 37 in the CBET group. Participants in CBCR achieved a greater mean (SD) increase in peak V̇o2 than those in CBET (2.1 [2.8] mL/kg/min vs 0.8 [2.5] mL/kg/min), with a between-group mean difference of 1.3 mL/kg/min (95% CI, 0.1-2.6 mL/kg/min; P = .03). Compared with the CBET group, the CBCR group also attained a greater mean (SD) reduction in systolic BP (-12.3 [11.8] mm Hg vs -1.9 [12.9] mm Hg; P < .001), diastolic BP (-5.0 [5.7] mm Hg vs -0.5 [7.0] mm Hg; P = .003), and BMI (-1.2 [0.9] vs 0.2 [0.7]; P < .001) and greater mean (SD) improvements in PA levels (1035.2 [735.7] metabolic equivalents [METs]/min/wk vs 34.1 [424.4] METs/min/wk; P < .001), QOL (14.0 [10.0] points vs 0.4 [12.9] points; P < .001), and health literacy scores (2.7 [1.6] points vs 0.1 [1.4] points; P < .001). Exercise adherence was significantly higher in the CBCR group than in the CBET group (mean [SD] sessions completed, 90.3% [11.8%] vs 68.4% [22.1%]; P < .001). The CORE trial showed that a cardio-oncology rehabilitation model among cancer survivors with high cardiovascular risk was associated with greater improvements in peak V̇o2 compared with usual care encompassing an exercise intervention in a community setting. The CBCR also showed superior results in exercise adherence, cardiovascular risk factor control, QOL, and health literacy. ClinicalTrials.gov Identifier: NCT05132998.

Loss of Otopetrin 1 affects thermoregulation during fasting in mice.

Otopetrin 1 (OTOP1) is a proton channel that is highly expressed in brown adipose tissue. We examined the physiology of Otop1-/- mice, which lack functional OTOP1. Mice were studied by indirect calorimetry and telemetric ambulatory body temperature monitoring. Mitochondrial function was measured as oxygen consumption and extracellular acidification. Otop1-/- mice had similar body temperatures as control mice at baseline and in response to cold and hot ambient temperatures. However, in response to fasting the Otop1-/- mice exhibited an exaggerated hypothermia and hypometabolism. Similarly, in ex vivo tests of Otop1-/- brown adipose tissue mitochondrial function, there was no change in baseline oxygen consumption, but the oxygen consumption was reduced after maximal uncoupling with FCCP and increased upon stimulation with the β3-adrenergic agonist CL316243. Mast cells also express Otop1, and Otop1-/- mice had intact, possibly greater hypothermia in response to mast cell activation by the adenosine A3 receptor agonist MRS5698. No increase in insulin resistance was observed in the Otop1-/- mice. Loss of OTOP1 does not change basal function of brown adipose tissue but affects stimulated responses.

OXYGEN CONSUMPTION AS AN EARLY WARNING SYSTEM IN THE CRITICALLY ILL.

Introduction: In this study, we assessed whether changes in oxygen consumption (VO 2 ) and other metabolic parameters could be used as an early warning system for detecting clinical deterioration in mechanically ventilated patients. Methods: This was a prospective cohort study of adult patients requiring mechanical ventilation between February 2016 and March 2019. We looked for changes in VO 2 , carbon dioxide production (VCO 2 ), respiratory quotient (RQ), and end-tidal carbon dioxide (EtCO 2 ), occurring prior to clinical deterioration. Clinical deterioration was predefined as a requirement of vasopressor, an increase in serum lactate by 20% where at least one value was above 3 mmol/L, or a decrease in hemoglobin by 20% in the 4 hours prior to clinical deterioration. Results A total of 141 patients were included. There were no detectable changes in VO 2 , VCO 2 , and EtCO 2 within the 4 hours prior to any clinical deterioration. RQ increased significantly within the 4 hours prior to an increase in lactate as compared with no increase in lactate, but there were no detectable changes prior to other clinical deteriorations. Conclusions RQ has the potential to be an early marker of tissue hypoperfusion or mitochondrial dysfunction. However, future studies are necessary to evaluate the use of RQ as a bedside monitor in critical care settings.