Dataset Information

Intact skeletal muscle mitochondrial enzyme activity but diminished exercise capacity in advanced heart failure patients on optimal medical and device therapy.

ABSTRACT:

Background

A skeletal myopathy, perhaps attributable to neuro-endocrine excitation or disuse, has been described in heart failure (HF) patients, and is thought to contribute to their exercise limitation. Our purpose was to assess biochemical and morphometric characteristics of skeletal muscles of HF patients on optimal HF therapy. A secondary purpose was to explore the effects of clonidine, which interrupts the neuro-endocrine excitation, on these same muscle characteristics.

Methods and results

Eleven HF patients (50.8 ± 3.4 years, peak VO2 11.6 ± 2.5 ml/kg/min) underwent two vastus lateralis biopsies (pre/post clonidine). Baseline values were compared to biopsies in 11 age-matched, healthy controls. Scatter plots of individual values for each mitochondrial enzyme revealed almost complete overlap between HF and control groups; mean values, although tending to be greater in controls versus HF patients, were not significantly different. The proportion of type 1 fibers was diminished in 10 of 11 patients. There was no difference in any of the variables after 3 months clonidine versus placebo.

Conclusion

In HF patients treated with optimal medical and device therapy, characteristic abnormalities of mitochondrial enzyme activity are not found, but muscle fiber type shifts are present. The remaining severe impairment in exercise capacity cannot be attributed to mitochondrial abnormalities.

SUBMITTER: Middlekauff HR

PROVIDER: S-EPMC3710307 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature

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Publications

Intact skeletal muscle mitochondrial enzyme activity but diminished exercise capacity in advanced heart failure patients on optimal medical and device therapy.

Middlekauff Holly R HR Verity M Anthony MA Horwich Tamara B TB Fonarow Gregg C GC Hamilton Michele A MA Shieh Perry P

Clinical research in cardiology : official journal of the German Cardiac Society 20130411 8

<h4>Background</h4>A skeletal myopathy, perhaps attributable to neuro-endocrine excitation or disuse, has been described in heart failure (HF) patients, and is thought to contribute to their exercise limitation. Our purpose was to assess biochemical and morphometric characteristics of skeletal muscles of HF patients on optimal HF therapy. A secondary purpose was to explore the effects of clonidine, which interrupts the neuro-endocrine excitation, on these same muscle characteristics.<h4>Methods ...[more]

PMID: 23575739

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Project description:BackgroundPatients suffering from chronic heart failure (CHF) show an increased prevalence of sarcopenia. Levosimendan is an effective drug for the treatment of heart failure, but its effect on sarcopenia is still unclear. We aimed to explore whether levosimendan could enhance skeletal muscle contractibility, improve skeletal muscle atrophy, and thus improve exercise tolerance of individuals with heart failure.MethodsC57BL6/J mice were used to establish the heart failure with sarcopenia model and injected of levosimendan. Mice were separated into control group, sham operation group, HF group, HF + solvent group, HF + levosimendan group, HF + sarcopenia group, HF + sarcopenia + solvent group, HF + sarcopenia + levosimendan group (n = 5-12). After the treatment, exercise capacity and cardiac function were evaluated. Muscle morphology, inflammation level and apoptosis levels were detected, in which mitochondrial function and oxidative stress level were also assessed.ResultLevosimendan could increase forelimb grip strength/body weight, hanging impulse, maximum running distance and time in mice with HF and sarcopenia (P < 0.0001 for all), and these improvements were independent of EF (P = 0.0019 for hanging impulse, P < 0.001 for forelimb grip strength/body weight and maximum running distance). Levosimendan directly increased the CSA of gastrocnemius in mice with HF and sarcopenia (P < 0.0001). After levosimendan injection, the proportion of slow muscle fibers increased (P < 0.0001), but this improvement of muscle fiber typing might be attributed to improved cardiac function (P > 0.05). Levosimendan also maintained mitochondrial membrane potential, decreased cleaved caspase-3 (P = 0.034), cleaved caspase-9 (P < 0.0001), Bax expression (P < 0.0001), and increased Bcl2 expression (P = 0.0036). This effect is independent of improved cardiac function (P = 0.028 for bax, P < 0.001 for cleaved caspase-9 and Bcl2). IL-6, TNF-α expression (P < 0.0001 for both) decreased, and SOD activity (P = 0.0038), GSH/GSSG ratio (P = 0.002) significantly increased in skeletal muscle after injection of levosimendan. The improvement in oxidative stress level was attributed to improved cardiac function (P > 0.05).ConclusionLevosimendan reduce the loss of skeletal muscle mitochondrial membrane potential, decrease the apoptosis, alleviate the inflammation and oxidative stress, and ultimately improve the exercise capacity of mice with heart failure and sarcopenia. Therefore, levosimendan may be a potential drug for the treatment of heart failure with sarcopenia.

Project description:Muscle wasting is a serious complication in heart failure patients. Oxidative stress and inflammation are implicated in the pathogenesis of muscle wasting. Oxidative stress leads to the formation of toxic lipid peroxidation products, such as 4-hydroxy-2-nonenal (HNE), which covalently bind with proteins and DNA and activate atrophic pathways. Whether the formation of lipid peroxidation products and metabolic pathways that remove these toxic products are affected during heart failure-associated skeletal muscle wasting has never been studied. Male C57BL/6J mice were subjected to sham and transverse aortic constriction (TAC) surgeries for 4, 8 or 14 weeks. Different skeletal muscle beds were weighed, and the total cross-sectional area of the gastrocnemius muscle was measured via immunohistochemistry. Muscle function and muscle stiffness were measured by a grip strength meter and atomic force microscope, respectively. Atrophic and inflammatory marker levels were measured via qRT‒PCR. The levels of acrolein and HNE-protein adducts, aldehyde-removing enzymes, the histidyl dipeptide-synthesizing enzyme carnosine synthase (CARNS), and amino acid transporters in the gastrocnemius muscle were measured via Western blotting and qRT‒PCR. Histidyl dipeptides and histidyl dipeptide aldehyde conjugates in the Gastrocnemius and soleus muscles were analyzed by LC/MS-MS. Body weight, gastrocnemius muscle and soleus muscle weights and the total cross-sectional area of the gastrocnemius muscle were decreased after 14 weeks of TAC. Heart weight, cardiac function, grip strength and muscle stiffness were decreased in the TAC-operated mice. Expression of the atrophic and inflammatory markers Atrogin1 and TNF-α, respectively, was increased ~ 1.5-2fold in the gastrocnemius muscle after 14 weeks of TAC (p < 0.05 and p = 0.004 vs sham). The formation of HNE and acrolein protein adducts was increased, and the expression of the aldehyde-removing enzyme aldehyde dehydrogenase (ALDH2) was decreased in the gastrocnemius muscle of TAC mice. Carnosine (sham: 5.76 ± 1.3 vs TAC: 4.72 ± 0.7 nmol/mg tissue, p = 0.04) and total histidyl dipeptide levels (carnosine and anserine; sham: 11.97 ± 1.5 vs TAC: 10.13 ± 1.4 nmol/mg tissue, p < 0.05) were decreased in the gastrocnemius muscle of TAC mice. Depletion of histidyl dipeptides diminished the aldehyde removal capacity of the atrophic gastrocnemius muscle. Furthermore, CARNS and TAUT protein expression were decreased in the atrophic gastrocnemius muscle. Our data reveals that reduced expression of ALDH2 and depletion of histidyl dipeptides in the gastrocnemius muscle during heart failure leads to the accumulation of toxic aldehydes and might contribute to muscle wasting.

Dataset Information

Intact skeletal muscle mitochondrial enzyme activity but diminished exercise capacity in advanced heart failure patients on optimal medical and device therapy.

Background

Methods and results

Conclusion

Publications

Intact skeletal muscle mitochondrial enzyme activity but diminished exercise capacity in advanced heart failure patients on optimal medical and device therapy.

Similar Datasets

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