Exercise capacity and cardiac hemodynamic response in female ApoE/LDLR(-/-) mice: a paradox of preserved V'O2max and exercise capacity despite coronary atherosclerosis.
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SUBMITTER: Wojewoda M
PROVIDER: S-EPMC4842974 | biostudies-other | 2016 Apr
REPOSITORIES: biostudies-other
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Project description:BackgroundExercise intolerance is a defining characteristic of heart failure with preserved ejection fraction (HFpEF). A marked rise in pulmonary capillary wedge pressure (PCWP) during exertion is pathognomonic for HFpEF and is thought to be a key cause of exercise intolerance. If true, acutely lowering PCWP should improve exercise capacity. To test this hypothesis, we evaluated peak exercise capacity with and without nitroglycerin to acutely lower PCWP during exercise in patients with HFpEF.MethodsThirty patients with HFpEF (70±6 years of age; 63% female) underwent 2 bouts of upright, seated cycle exercise dosed with sublingual nitroglycerin or placebo control every 15 minutes in a single-blind, randomized, crossover design. PCWP (right heart catheterization), oxygen uptake (breath × breath gas exchange), and cardiac output (direct Fick) were assessed at rest, 20 Watts (W), and peak exercise during both placebo and nitroglycerin conditions.ResultsPCWP increased from 8±4 to 35±9 mm Hg from rest to peak exercise with placebo. With nitroglycerin, there was a graded decrease in PCWP compared with placebo at rest (-1±2 mm Hg), 20W (-5±5 mm Hg), and peak exercise (-7±6 mm Hg; drug × exercise stage P=0.004). Nitroglycerin did not affect oxygen uptake at rest, 20W, or peak (placebo, 1.34±0.48 versus nitroglycerin, 1.32±0.46 L/min; drug × exercise P=0.984). Compared with placebo, nitroglycerin lowered stroke volume at rest (-8±13 mL) and 20W (-7±11 mL), but not peak exercise (0±10 mL).ConclusionsSublingual nitroglycerin lowered PCWP during submaximal and maximal exercise. Despite reduction in PCWP, peak oxygen uptake was not changed. These results suggest that acute reductions in PCWP are insufficient to improve exercise capacity, and further argue that high PCWP during exercise is not by itself a limiting factor for exercise performance in patients with HFpEF.RegistrationURL: https://www.Clinicaltrialsgov; Unique identifier: NCT04068844.
| S-EPMC9892242 | biostudies-literature
Project description:LDL cholesterol (LDL-C) contributes to coronary heart disease. Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases LDL-C by inhibiting LDL-C clearance. The therapeutic potential for PCSK9 inhibitors is highlighted by the fact that PCSK9 loss-of-function carriers exhibit 15-30% lower circulating LDL-C and a disproportionately lower risk (47-88%) of experiencing a cardiovascular event. Here, we utilized pcsk9(-/-) mice and an anti-PCSK9 antibody to study the role of the LDL receptor (LDLR) and ApoE in PCSK9-mediated regulation of plasma cholesterol and atherosclerotic lesion development. We found that circulating cholesterol and atherosclerotic lesions were minimally modified in pcsk9(-/-) mice on either an LDLR- or ApoE-deficient background. Acute administration of an anti-PCSK9 antibody did not reduce circulating cholesterol in an ApoE-deficient background, but did reduce circulating cholesterol (-45%) and TGs (-36%) in APOE*3Leiden.cholesteryl ester transfer protein (CETP) mice, which contain mouse ApoE, human mutant APOE3*Leiden, and a functional LDLR. Chronic anti-PCSK9 antibody treatment in APOE*3Leiden.CETP mice resulted in a significant reduction in atherosclerotic lesion area (-91%) and reduced lesion complexity. Taken together, these results indicate that both LDLR and ApoE are required for PCSK9 inhibitor-mediated reductions in atherosclerosis, as both are needed to increase hepatic LDLR expression.
| S-EPMC4617138 | biostudies-literature
Project description:Atherosclerosis is the preliminary cause of coronary artery disease, one of the diseases that ac-count for the largest number of fatal mortalities. Physical activity is an effective strategy to restrain atherosclerosis from deterioration. Evidence indicated that the changes of proteomic profile is highly associated with the atherosclerosis development, but the mechanism behind the exercise for atherosclerosis amelioration has not yet been investigated from the proteomics perspective. Hence, the proteomic profiles could further elucidate the systematic effects of exercise interven-tion on ApoE knockout atherosclerotic model and high fat diet intervention. In current study, Apoeem1Narl/Narl mice were randomly allocated into a normal diet (ND), western diet (WD) and WD with 12 weeks exercise intervention (WD EX) groups. The plasm proteome between WD and WD EX demonstrate the significant difference, and ten major pathways, including cardiovascular disease (CVD)–hematological disease, cellular compromise–inflammatory response, protein synthesis, connective tissue disorders, cellular movement–immune cell tracking, inflammatory response, etc., were generated by the IPA analysis. The fourteen proteins (PROS, PROZ, C2, F5, C5, SERPINA 10, FGB, FGG, CFB, F12, CRP, CFHR1, HABP2, and PPIA) critically involved in CVD–hematological disease pathway showed significant difference among groups. The PROS, F5, C5, FGG, and CFB levels associated with thrombosis and atherosclerosis induced by WD were significantly decreased by exercise intervention in WD EX. Furthermore, the F5 and FGG were well-demonstrated the important roles for thrombosis of atherosclerotic pathogenesis but the complement factor C5 in the development of atherosclerosis is not fully understood. In current study, the exercise could significantly alleviate the significantly elevated C5 and inflammation induced by WD group in accordance to amelioration of atherosclerosis. Therefore, exercise could mitigate chemotaxis through the modulation of the C5 level and innate immunity, thereby alle-viating the pathogenesis of atherosclerosis in western-diet induced obese mice.
2022-04-04 | PXD030951 | Pride
Project description:Key pointsHealthy older adults exhibit lower cardiorespiratory fitness ( V̇O2peak ) than young in the absence of any age-related difference in skeletal muscle mitochondrial capacity, suggesting central haemodynamics plays a larger role in age-related declines in V̇O2peak . Total physical activity did not differ by age, but moderate-to-vigorous physical activity was lower in older compared to young adults. Moderate-to-vigorous physical activity is associated with V̇O2peak and muscle oxidative capacity, but physical inactivity cannot entirely explain the age-related reduction in V̇O2peak .AbstractDeclining fitness ( V̇O2peak ) is a hallmark of ageing and believed to arise from decreased oxygen delivery and reduced muscle oxidative capacity. Physical activity is a modifiable lifestyle factor that is critical when evaluating the effects of age on parameters of fitness and energy metabolism. The objective was to evaluate the effects of age and sex on V̇O2peak , muscle mitochondrial physiology, and physical activity in young and older adults. An additional objective was to assess the contribution of skeletal muscle oxidative capacity to age-related reductions in V̇O2peak and determine if age-related variation in V̇O2peak and muscle oxidative capacity could be explained on the basis of physical activity levels. In 23 young and 52 older men and women measurements were made of V̇O2peak , mitochondrial physiology in permeabilized muscle fibres, and free-living physical activity by accelerometry. Regression analyses were used to evaluate associations between age and V̇O2peak , mitochondrial function, and physical activity. Significant age-related reductions were observed for V̇O2peak (P < 0.001), but not muscle mitochondrial capacity. Total daily step counts did not decrease with age, but older adults showed lower moderate-to-vigorous physical activity, which was associated with V̇O2peak (R2 = 0.323, P < 0.001) and muscle oxidative capacity (R2 = 0.086, P = 0.011). After adjusting for sex and physical activity, age was negatively associated with V̇O2peak but not muscle oxidative capacity. Healthy older adults exhibit lower V̇O2peak but preserved mitochondrial capacity compared to young. Physical activity, particularly moderate-to-vigorous, is a key factor in observed age-related changes in fitness and muscle oxidative capacity, but cannot entirely explain the age-related reduction in V̇O2peak .
| S-EPMC8284426 | biostudies-literature
Project description:Investigating the mechanisms of time-restricted feeding that can prevent weight gain, hypercholesterolemia, and atherosclerosis in LDLR-KO mice.
2024-08-29 | GSE210460 | GEO
Project description:Heart failure with preserved ejection fraction (HFpEF) is a clinical syndrome characterized by impaired exercise capacity due to shortness of breath and/or fatigue. Assessment of diastolic dysfunction at rest and with exercise may provide insight into the pathophysiology of exercise intolerance in HFpEF.To measure echocardio-Doppler-derived parameters of diastolic function as they relate to various indices of aerobic exercise capacity in HFpEF.We selected 16 subjects with clinically stable HFpEF, no evidence of volume overload, but impaired functional capacity by cardiopulmonary exercise testing [peak oxygen consumption (VO2 )]. We measured the transmitral E and A flow velocities, E/A ratio, and E deceleration time (DT) and tissue Doppler E' velocity. We also indexed the E' to the DT, as additional measure of impaired relaxation (E'DT ), and calculated the diastolic functional reserve index (DFRI), as the product of E' at rest and change in E' with exercise.E' velocity, at rest and peak exercise, as well as the DFRI positively correlated with peak VO2 , whereas DT, E'DT , and E/E' with exercise inversely correlated with peak VO2 . Of note, the E'DT at rest also significantly predicted E' velocity at peak exercise (R = +0.81, P < 0.001). Exercise E' was the only independent predictor of peak VO2 at multivariable analysis (R = +0.67, P = 0.005).The E' velocity at peak exercise is a strong and independent predictor of aerobic exercise capacity as measured by peak VO2 in patients with HFpEF, providing the link between abnormal myocardial relaxation with exercise and impaired aerobic exercise capacity in HFpEF.
| S-EPMC5542717 | biostudies-other
Project description:BackgroundArterial stiffness is thought to contribute to the pathophysiology of heart failure with preserved ejection fraction (HFpEF). We sought to examine arterial stiffness in HFpEF and hypertension and investigate associations of arterial and left ventricular hemodynamic responses to exercise.Methods and resultsA total of 385 symptomatic individuals with an EF of ≥50% underwent upright cardiopulmonary exercise testing with invasive hemodynamic assessment of arterial stiffness and load (aortic augmentation pressure, augmentation index, systemic vascular resistance index, total arterial compliance index, effective arterial elastance index, and pulse pressure amplification) at rest and during incremental exercise. An abnormal hemodynamic response to exercise was defined as a steep increase in pulmonary capillary wedge pressure relative to cardiac output (∆PCWP/∆CO > 2 mm Hg/L/min). We compared rest and exercise measures between HFpEF and hypertension in multivariable analyses. Among 188 participants with HFpEF (mean age 61 ± 13 years, 56% women), resting arterial stiffness parameters were worse compared with 94 hypertensive participants (mean age 55 ± 15 years, 52% women); these differences were accentuated during exercise in HFpEF (all P ≤ .0001). Among all participants, exercise measures of arterial stiffness correlated with worse ∆PCWP/∆CO. Specifically, a 1 standard deviation higher exercise augmentation pressure was associated with 2.15-fold greater odds of abnormal LV hemodynamic response (95% confidence interval 1.52-3.05; P < .001). Further, exercise measures of systemic vascular resistance index, elastance index, and pulse pressure amplification correlated with a lower peak oxygen consumption.ConclusionsExercise accentuates the increased arterial stiffness found in HFpEF, which in turn correlates with left ventricular hemodynamic responses. Unfavorable ventricular-vascular interactions during exercise in HFpEF may contribute to exertional intolerance and inform future therapeutic interventions.
| S-EPMC8180488 | biostudies-literature
Project description:OBJECTIVES:This study sought to define the invasive hemodynamic correlates of peak oxygen consumption (Vo2) in both supine and upright exercise in heart failure with preserved ejection fraction (HFpEF) and evaluate its diagnostic role as a method to discriminate HFpEF from noncardiac etiologies of dyspnea (NCD). BACKGROUND:Peak Vo2 is depressed in patients with HFpEF. The hemodynamic correlates of reduced peak Vo2 and its role in the clinical evaluation of HFpEF are unclear. METHODS:Consecutive patients with dyspnea and normal EF (N = 206) undergoing both noninvasive upright and invasive supine cardiopulmonary exercise testing were examined. Patients with invasively verified HFpEF were compared with those with NCD. RESULTS:Compared with NCD (n = 72), HFpEF patients (n = 134) displayed lower peak Vo2 during upright and supine exercise. Left heart filling pressures during exercise were inversely correlated with peak Vo2 in HFpEF, even after accounting for known determinants of O2 transport according to the Fick principle. Very low upright peak Vo2 (<14 ml/kg/min) discriminated HFpEF from NCD with excellent specificity (91%) but poor sensitivity (50%). Preserved peak Vo2 (>20 ml/kg/min) excluded HFpEF with high sensitivity (90%) but had poor specificity (49%). Intermediate peak Vo2 cutoff points were associated with substantial overlap between cases and NCD. CONCLUSIONS:Elevated cardiac filling pressure during exercise is independently correlated with reduced exercise capacity in HFpEF, irrespective of body position, emphasizing its importance as a novel therapeutic target. Noninvasive cardiopulmonary testing discriminates HFpEF and NCD at high and low values, but additional testing is required for patients with intermediate peak Vo2.
| S-EPMC6076329 | biostudies-literature
Project description:The population of older adults is exponentially expanding. Alongside aging comes the onset of chronic disease, decline of functional capacity, and reduced quality of life. Thus, this population increase will stress the capacity and financial viability of health and long-term care systems. Developing pre-clinical models for age-related functional decline is imperative to advancing therapies that extend healthspan and prolong independence. Previously in a cross-sectional study, we established a powerful composite scoring system we termed CFAB (comprehensive functional assessment battery). CFAB measures physical function and exercise capacity using well-validated determinants to measure overall motor function, fore-limb strength, four-limb strength/endurance, aerobic capacity, and volitional exercise/activity rate. In the current work, we used CFAB to track cohorts of male and female C57BL/6 mice over the lifespan (measuring CFAB at 6, 12, 18, 24, and 28 months of age). Overall, we found statistically significantly declining function as the mice aged, with some differences between males and females in trajectory and slope. We also determined that body mass changes presented differently between sexes, and tracked body composition (fat percentage, using magnetic resonance imagery) in females. In a subset of mice, we tracked in vivo contractile physiology noting declines in plantar flexor maximum isometric torque. In summary, our data suggest that males and females declined at different rates. We confirmed the efficacy of CFAB to track longitudinal changes in exercise capacity and physical fitness in both males and females, further validating the system to track age-related functional decline.
| S-EPMC11312590 | biostudies-literature
Project description:Inorganic nitrate (NO3(-)), abundant in certain vegetables, is converted to nitrite by bacteria in the oral cavity. Nitrite can be converted to nitric oxide in the setting of hypoxia. We tested the hypothesis that NO3(-) supplementation improves exercise capacity in heart failure with preserved ejection fraction via specific adaptations to exercise.Seventeen subjects participated in this randomized, double-blind, crossover study comparing a single dose of NO3-rich beetroot juice (NO3(-), 12.9 mmol) with an identical nitrate-depleted placebo. Subjects performed supine-cycle maximal-effort cardiopulmonary exercise tests, with measurements of cardiac output and skeletal muscle oxygenation. We also assessed skeletal muscle oxidative function. Study end points included exercise efficiency (total work/total oxygen consumed), peak VO2, total work performed, vasodilatory reserve, forearm mitochondrial oxidative function, and augmentation index (a marker of arterial wave reflections, measured via radial arterial tonometry). Supplementation increased plasma nitric oxide metabolites (median, 326 versus 10 ?mol/L; P=0.0003), peak VO2 (12.6±3.7 versus 11.6±3.1 mL O2·min(-1)·kg(-1); P=0.005), and total work performed (55.6±35.3 versus 49.2±28.9 kJ; P=0.04). However, efficiency was unchanged. NO3(-) led to greater reductions in systemic vascular resistance (-42.4±16.6% versus -31.8±20.3%; P=0.03) and increases in cardiac output (121.2±59.9% versus 88.7±53.3%; P=0.006) with exercise. NO3(-) reduced aortic augmentation index (132.2±16.7% versus 141.4±21.9%; P=0.03) and tended to improve mitochondrial oxidative function.NO3(-) increased exercise capacity in heart failure with preserved ejection fraction by targeting peripheral abnormalities. Efficiency did not change as a result of parallel increases in total work and VO2. NO3(-) increased exercise vasodilatory and cardiac output reserves. NO3(-) also reduced arterial wave reflections, which are linked to left ventricular diastolic dysfunction and remodeling.www.clinicaltrials.gov. Unique identifier: NCT01919177.
| S-EPMC5823250 | biostudies-literature