JACC
HOME SUBSCRIPTIONS CURRENT ISSUE PAST ISSUES CARDIOSOURCE SEARCH HELP FEEDBACK
QUICK SEARCH:   [advanced]


     

J Am Coll Cardiol, 2001; 38:947-954
© 2001 by the American College of Cardiology Foundation
This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mettauer, B.
Right arrow Articles by Ventura-Clapier, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mettauer, B.
Right arrow Articles by Ventura-Clapier, R.

CLINICAL STUDY

Oxidative capacity of skeletal muscle in heart failure patients versus sedentary or active control subjects

Bertrand Mettauer, MD, PhD*, Joffrey Zoll, BS*, Hervé Sanchez, BS*, Eliane Lampert, MD*, Florence Ribera, BS*, Vladimir Veksler, MD, PhD{dagger}, Xavier Bigard, MD, PhD{ddagger}, Philippe Mateo, PhD{dagger}, Eric Epailly, MD*, Jean Lonsdorfer, MD* and Renée Ventura-Clapier, PhD{dagger}

* Département de Physiologie, Faculté de Médecine, Université Louis Pasteur, Strasbourg, France
{dagger} Cardiologie Cellulaire et Moléculaire U-446 INSERM, Faculté de Pharmacie, Université Paris-Sud, Châtenay-Malabry, France
{ddagger} Unité de Bioénergétique, CRSSA, La-Tronche Cedex, France

Manuscript received December 7, 2000; revised manuscript received May 21, 2001, accepted June 11, 2001.

Reprint requests and correspondence: Dr. Bertrand Mettauer, Département de Physiologie, Faculté de Médecine, 11, rue Humann, 67000 Strasbourg, France
Bertrand.Mettauer{at}physio-ulp.u-Strasbg.fr


   Abstract
Top
 Abstract
Methods
 Results
 Discussion
 References
 
OBJECTIVES

We investigated the in situ properties of muscle mitochondria using the skinned fiber technique in patients with chronic heart failure (CHF) and sedentary (SED) and more active (ACT) controls to determine: 1) whether respiration of muscle tissue in the SED and ACT groups correlates with peak oxygen consumption (pVO2), 2) whether it is altered in CHF, and 3) whether this results from deconditioning or CHF-specific myopathy.

BACKGROUND

Skeletal muscle oxidative capacity is thought to partly determine the exercise capacity in humans and its decrease to participate in exercise limitation in CHF.

METHODS

M. Vastus lateralis biopsies were obtained from 11 SED group members, 10 ACT group members and 15 patients with CHF at the time of transplantation, saponine-skinned and placed in an oxygraphic chamber to measure basal and maximal adenosine diphosphate (ADP)-stimulated (Vmax) respiration rates and to assess mitochondrial regulation by ADP. All patients received angiotensin-converting enzyme (ACE) inhibitors.

RESULTS

The pVO2 differed in the order CHF < SED < ACT. Compared with SED, muscle alterations in CHF appeared as decreased citrate synthase, creatine kinase and lactate dehydrogenase, whereas the myosin heavy chain profile remained unchanged. However, muscle oxidative capacity (Vmax, CHF: 3.53 ± 0.38; SED: 3.17 ± 0.48; ACT: 7.47 ± 0.73, µmol O2·min–1·g–1dw, p < 0.001 vs. CHF and SED) and regulation were identical in patients in the CHF and SED groups, differing in the ACT group only. In patients with CHF, the correlation between pVO2 and muscle oxidative capacity observed in controls was displaced toward lower pVO2 values.

CONCLUSIONS

In these patients, the disease-specific muscle metabolic impairments derive mostly from extramitochondrial mechanisms that disrupt the normal symmorphosis relations. The possible roles of ACE inhibitors and level of activity are discussed.

Abbreviations and Acronyms
  ACE = angiotensin-converting enzyme
  ACR = acceptor control ratio
  ACT = active normal controls
  ADP = adenosine diphosphate
  CHF = chronic heart failure
  CK = creatine kinase
  CS = citrate synthase
  HR = heart rate
  LDH = lactate dehydrogenase
  MHC = myosin heavy chain
  NO = nitric oxide
  RER = respiratory exchange ratio
  SED = true sedentary controls
  VADP = ADP-stimulated tissue oxygen uptake
  VCO2 = carbon dioxide produced
  Vmax = maximal tissue oxygen uptake
  VO2max = predicted normal maximal oxygen uptake
  VO2 = oxygen uptake
  VT = ventilatory threshold

Factors limiting maximal oxygen consumption (VO2) during exercise in humans involve both central and peripheral factors. Among the latter, oxidative enzymes or mitochondrial density of vastus lateralis muscle have been shown to correlate with exercise capacity (1). Chronic heart failure (CHF) is characterized by an increasingly severe exertional handicap that does not correlate with the degree of ventricular dysfunction but represents one of the best predictors of mortality (2). It is commonly accepted that an abnormal muscle metabolism, partly unrelated to oxygen supply, contributes to the exercise impairment (2–4). A comparison with controls suggests that the increased lactate production (5), the increased phosphocreatine breakdown and intracellular acidosis (4) and the decreased rate of ATP resynthesis (2,4) result from abnormalities at the mitochondrial level. This is supported by the observation of a diminished mitochondrial density (1) and activity of selected oxidative enzymes (6,7) and by a recent report of our group showing decreased skeletal muscle oxidative capacity and mitochondrial regulation in a rat model of CHF (8). However, the intrinsic mitochondrial function has never been directly assessed in patients with CHF. Mechanisms upstream of mitochondria also contribute to the patient’s exertional handicap. A diminished muscle blood flow (5), an altered pattern of fiber recruitment (9), an increased production of tissue nitric oxide (NO) by the inducible NO synthase (10), and a decreased muscular capillary density (1,11) have all been suggested to participate in CHF exercise intolerance. Moreover, since previous studies did not always include a truly sedentary control group, they may have attributed to CHF changes that may have resulted from deconditioning only (11).

The aim of this study was, thus, to compare the intrinsic mitochondrial function, enzymatic equipment and myosin heavy chain (MHC) profile of biopsy samples from the vastus lateralis muscle in patients with CHF to those of truly sedentary (SED) or more active (ACT) controls. As selective permeabilization of cellular membranes offers the unique opportunity to study in situ the oxidative capacity of muscle cells and the mitochondrial regulatory properties, we adapted to human samples the oxygraphic respiration assessment of skinned muscle fibers, which has previously been validated in animals (12).


   Methods
Top
 Abstract
 Methods
Results
 Discussion
 References
 
Subjects and exercise testing.   Fifteen consecutive New York Heart Association class III patients with CHF were included in the study at the time of heart transplantation. Their characteristics are given in Table 1. Causes of heart failure were dilated idiopathic cardiomyopathy in nine patients, ischemic heart disease in four patients, congenital heart disease in one patient and valvular disease in one patient. Their peak VO2 was 13.2 ml·min–1·kg–1 ± 0.6 ml·min–1·kg–1. All patients received diuretics and angiotensin-converting enzyme (ACE) inhibitors. These patients’ exercise and muscle biopsy parameters were compared with those of 11 SED and 10 ACT controls who volunteered for the study (Table 1). We classified our volunteers as SED if their peak VO2 was, at most, equal to 110% of the predicted normal maximal VO2 (VO2max) according to Wasserman’s formulas (13) and as ACT if their peak VO2 was over 110% of predicted. All subjects gave their informed consent to participate in the study that had been approved by our institution’s ethics committee and underwent a cycloergometric incremental symptom-limited exercise test while measuring the VO2 and the carbon dioxide produced (VCO2) by means of a metabolic cart (Medical Graphics, St. Paul, Minnesota). In CHF patients, exercise tests (10 W·min–1) were repeated every three months to assess urgency, the last pretransplantation values being taken for this study. In controls, the exercise test increments were designed (15 W·min–1 to 25 W·min–1) to exhaust the subject in 10 min to 15 min and took place within two weeks of their biopsy. The aerobic-anaerobic transition was determined by the ventilatory threshold (VT) defined by V-slope analysis (13). These tests yielded the rest, VT and peak VO2, respiratory exchange ratio ([RER] = VCO2/VO2) and HR.


View this table:
[in this window]
[in a new window]
  		Table 1 Group Characteristics

 
Skeletal muscle biopsy.   M. Vastus lateralis tissue was taken by the Bergström biopsy technique under general anesthesia in patients and local anesthesia in controls. One part was immediately frozen in liquid nitrogen for enzymatic and isomyosin studies. Thin bundles (diameter: 100 µm to 200 µm) were immediately dissected as previously described (14) in iced relaxing solution containing (in mM) EGTA-calcium buffer 10 (free Ca2+ concentration 100 nM), MgCl2 1, taurine 20, DTT 0.5, imidazole 20 (pH 7.1), MgATP 5, PCr 15, at ionic strength 160 (potassium methanesulfonate) and permeabilized for 30 min with 50 µg·ml–1 saponin for respiration studies.

Mitochondrial respiration.   Respiratory parameters of the total mitochondrial population were studied in situ as previously described (12,14) using a Clark electrode (Strathkelvin Instruments, Glasgow, Scotland) in a water-jacketed oxygraphic cell containing 3 ml of respiration solution (see subsequent text) at 22°C with continuous stirring. Respiration rates were expressed as µmol O2·min–1·g–1 dry weight. Respiration solution had the same composition as the relaxing solution except that MgATP and PCr were replaced by 5 mM glutamate, 2 mM malate as substrates and 3 mM phosphate and 2mg·ml–1 fatty acid free bovine serum albumin. The adenosine diphosphate (ADP)-stimulated respiration (VADP) above basal oxygen consumption was plotted as a function of ADP with and without creatine (20 mM). The apparent Km for ADP and VADP were calculated using a nonlinear fitting of the Michaelis-Menten equation. Maximal respiration rate (Vmax) is (VADP + basal oxygen consumption). The acceptor control ratio (ACR) is Vmax/basal oxygen consumption. As an example, mitochondrial oxygen consumption in function of ADP concentration (raw data) and the fitting procedure for a representative subject with CHF and an ACT subject are shown in Figure 1.



View larger version (32K):
[in this window]
[in a new window]
  		Figure 1 Examples of the Michaelis-Menten kinetics of the oxygen consumption of permeabilized vastus lateralis myofibers to increasing levels of the phosphate acceptor adenosine diphosphate (ADP). (A) Raw data obtained by myofibers respiration within the oxygraphic chamber from a representative patient with chronic heart failure (CHF) (upper) and an active control (lower). The tissue O2 consumption (V, µmoles O2·min–1·g–1 dry weight) increases with increasing doses of the phosphate acceptor ADP. These experiments were performed in the absence (thick line) or in the presence (thin line) of 20 mM creatine. Panel B shows the ADP-related respiration characterizing the Michaelis and Menten kinetics of ADP phosphorylation for the same CHF (interrupted lines) or active normal controls (ACT) (continuous line) groups as in panel A. The upper part represents the experiments without creatine and the lower part those with 20 mM creatine. The striking difference in maximal tissue oxygen uptake between the patients with CHF and the active control group is reflected by the differing asymptotic values of O2 uptake. In CHF, the fast increase in oxygen uptake with ADP reflects the low Km without creatine (42 µM), which is unchanged with creatine (25 µM). In the active control, the Km is much higher (214 µM) and decreases with creatine (59 µM).

 
Enzyme analysis.   Part of the frozen tissue samples were weighed, homogenized into cold buffer (30 mg·mL–1) containing (in mM): HEPES 5 (pH 8.7), EGTA 1, MgCl2 5 and Triton X-100 (0.1%) and incubated for 60 min at 0°C to ensure complete enzyme extraction. Creatine kinase (CK) and lactate dehydrogenase (LDH) were assayed (30°C, pH 7.5) using a coupled enzyme system as previously described (15). Creatine kinase and LDH isoenzymes were separated using agarose gel (1%) electrophoresis performed at 200 V for 90 min. Individual isoenzymes were resolved either by incubating the gels with a coupled enzyme system (CK) or a commercial revelation system (Sigma LDH reagent kit, Saint Quentin, France) followed by image analysis.

MHC.   In the remaining frozen tissue, myosin was crudely extracted in a high ionic strength buffer as previously described (15). The MHCs were separated in 8% acrylamide-bis (50:1) slab gels at constant voltage (70 V) for 28 h and stained with Coomassie blue, then scanned by laser densitometry (Ultroscan XL, Turku, Finland).

Statistical analysis.   The values are expressed as means ± SEM. We used one-way analysis of variance (ANOVA) followed by a Student-Neumann-Keuls postprocedure to compare the CHF, SED and ACT groups. A two-way ANOVA was used to determine statistical differences in HR and respiratory metabolic data (subject group, level of exercise). When appropriate, differences between groups were tested with a Newman-Keuls post hoc test. Within each group the comparison of the Km with and without creatine were performed by a paired t test. Significance was taken as p ≤ 0.05.


   Results
Top
 Abstract
 Methods
 Results
Discussion
 References
 
Exercise studies.   By design, the VO2 to weight ratio were all very different among groups (13.2 ± 0.6 ml·min–1·kg–1; 27.3 ± 1.4 ml·min–1·kg–1 and 43.0 ± 2.5 ml·min–1·kg–1 in the CHF, SED and ACT groups, respectively, all p < 0.001), as were the percentages of predicted peak VO2: <50% of predicted values in patients with CHF, close to the predicted values in the SED group and 42% higher in the ACT group than in the SED group. While ages and heights were similar among groups, the SED group was heavier than the ACT group and the CHF group (Table 1). The gas exchanges at rest and during the incremental symptom-limited exercise are presented in Table 2. A two-way interaction between subject groups and exercise level was detected for VO2 (p < 0.001) and HR (p < 0.001). This means that the changes in these parameters during exercise were strongly dependent of the subject group. Although gas exchanges were similar among groups at rest, the RER was slightly higher in the CHF group. The resting HR also tended to be higher in patients with CHF, being significantly higher than that in the ACT controls. At the VT, most parameters were lower in patients with CHF than in the SED and ACT groups except for the RER, which was similar among groups. At peak exercise, all parameters were clearly lower in patients with CHF except the RER, which was similar and reached values indicating that all subjects reasonably approached exhaustion. Most VT and peak exercise parameters appeared to be higher in the ACT group than in the SED group according to their differences in fitness.


View this table:
[in this window]
[in a new window]
  		Table 2 Gas Exchanges During the Incremental Exercise Test

 
Mitochondrial function.   The respiratory parameters of the whole mitochondrial population of muscle biopsies was directly assessed in fibers after membrane permeabilization by saponin. Basal respiration of myofibers was similar in the three groups (1.22 ± 0.11 µmol O2·min–1·g–1 dry weight, 1.26 ± 0.18 µmol O2·min–1·g–1 dry weight and 1.10 ± 0.21 µmol O2·min–1·g–1 dry weight, respectively, in the CHF, SED and ACT groups, p = 0.20). Despite the much lower peak and VT VO2 in patients with CHF, the Vmax of myofibers, representing the maximal oxidative phosphorylation capacity of the mitochondria in the presence of saturating amounts of ADP, were similar in patients with CHF and SED controls (Fig. 2), whereas it was two times higher in the ACT group than in both the SED and CHF groups. The ACR, representing the degree of coupling between oxidation and phosphorylation, was also similar in the CHF and SED groups (2.86 ± 0.24 vs. 2.81 ± 0.42, respectively, p = NS), whereas it was higher in the ACT group (5.74 ± 0.80, p < 0.001 vs. the SED and CHF groups, overall p = 0.0002). Km for ADP was low and did not change with the addition of creatine in patients with CHF or in the SED group, whereas it was higher and diminished with creatine in the ACT group (Fig. 3). Muscle Vmax was linearly related to the peak VO2 in controls and in patients but only insignificantly in the latter because of the narrow range of values (a peak VO2 < 14 ml·min–1·kg–1 being among the selection criteria for transplantation). Moreover, a strong correlation was also observed with VO2 at VT, a parameter more closely related to the endurance capacity (Fig. 4B). The enzymes, their isoforms and percentages of MHC are presented in Table 3. The content of the intramitochondrial Krebs cycle enzyme citrate synthase (CS) was significantly lower in the CHF group and higher in the ACT group when compared with the SED group. Total CK and cytosolic MM-CK were lower in the CHF group only, whereas MB-CK was higher in the ACT group only. Total LDH activity was also lower in the CHF group, whereas H-LDH isoform was higher in the ACT group. The adenylate kinase was similar in all groups. Finally, no difference in myosin isoforms was observed in the CHF group compared with the SED group, while in the ACT group, the percentage of MHC-1 was higher than it was in the SED group, and MHC-2X was lower than that in the CHF group.



View larger version (32K):
[in this window]
[in a new window]
  		Figure 2 Comparison between exercise capacity and oxidative capacity of vastus lateralis muscle. The maximal adenosine diphosphate (ADP)-stimulated respiration rate of the saponin-skinned fibers (maximal tissue oxygen uptake [Vmax], µmol O2·min–1·g–1 dry weight tissue, left panel) were identical between patients with chronic heart failure (CHF) (open bars) and sedentary controls (SED) (hatched bars), both differing from active controls (ACT) (black bars). The peak oxygen uptake ([VO2 peak] ml·min–1·kg–1, middle panel) and the O2 uptake at the ventilatory threshold ([VO2 at VT] ml·min–1·kg–1, right panel), representing exercise capacity, highly differed among groups in the order CHF < SED < ACT.

 


View larger version (26K):
[in this window]
[in a new window]
  		Figure 3 Apparent Michaelis-Menten constant without and with creatine for the adenosine diphosphate (ADP)-stimulated respiration of myofibers. The apparent Michaelis-Menten constant ([KmADP] µM) of the saponin-skinned fibers without creatine (hatched bars) were similarly low in patients with chronic heart failure (CHF) and sedentary controls (SED) and unchanged with the addition of creatine (black bars). In the active controls (ACT) the high Km value, which decreases with creatine, shows that the oxygen consumption is controlled by the mitochondrial creatine kinase.

 


View larger version (16K):
[in this window]
[in a new window]
  		Figure 4 Correlation between exercise capacity and muscle oxidative capacity. (A) The relation between myofibers oxidative capacity and peak oxygen uptake (VO2 peak) (ml·min–1·kg–1) of patients with chronic heart failure (CHF) (open circles) is shifted leftward from the normal relation in controls (sedentary subjects: open triangles; active controls: closed triangles). (B) The relation between myofibers oxidative capacity and VO2 (ml·min–1·kg–1) at ventilatory threshold (VT), taken as an index of endurance capacity, of CHF patients is also shifted leftward from the normal relation in controls (symbols as in A).

 

View this table:
[in this window]
[in a new window]
  		Table 3 Enzymes and MHC

 

   Discussion
Top
 Abstract
 Methods
 Results
 Discussion
References
 
This study is the first direct assessment of skeletal muscle mitochondrial intrinsic oxidative capacity and regulation in end-stage CHF, made by means of oxygraphic techniques in saponin-skinned myofibers. This is also the first determination of the ADP sensitivity of in situ mitochondria in patients with CHF and healthy subjects. The main finding is that oxidative capacity and mitochondrial regulation clearly differed between sedentary and active controls but that the intrinsic mitochondrial function in our patients with CHF did not differ from that of truly sedentary controls.

Skeletal muscle oxidative characteristics.   Respiration of skinned fibers is the unique mean to assess the function of the whole mitochondrial population within its cellular environment, with saturating amounts of oxygen and substrates (12). This allows a direct measurement of muscle oxidative capacity. As expected, this parameter was lower in the SED group than in the ACT group. However, oxidative capacity of skeletal muscle of patients with CHF was identical to that of the SED group, suggesting that the mitochondrial oxidative phosphorylation pathway is preserved in these patients. Moreover, we could demonstrate that mitochondrial regulation by the phosphate acceptor ADP or by the mitochondrial CK was identical between the SED and CHF groups, with both groups greatly differing from the ACT group. The characteristics of mitochondrial respiration in the SED and CHF groups are close to those described for fast-glycolytic muscle of rodents, while those of the ACT group approach those for the slow-oxidative muscle, that is, high oxidative capacity, low sensitivity to external ADP and control of respiration by mitochondrial CK (12,15,16). These differences suggest a higher oxidative potential in ACT muscles and are in line with the decreased sensitivity of mitochondrial respiration to external ADP with increased physical activity already indirectly evoked by Tonkonogi et al. (17). The low permeability for ADP of mitochondria from oxidative muscles has been interpreted as a means of directly connecting mitochondrial respiration to the CK shuttle (18). This enables efficient PCr synthesis at sites of ATP production, fast energy transfer by cytosolic CK and efficient ATP rephosphorylation by the myosin-bound CK (16).

Biochemical studies.   Despite great variability in patients, an increase in the relative content of MHC-2X could be observed from the ACT to SED to CHF groups, consistent with previous studies (6,19). Earlier studies reported less slow and higher fast fiber types in patients with CHF (6), but Vescovo et al. (19) showed that ACE inhibitor treatment normalized their abnormal MHC profile, thus explaining the insignificant difference in MHC between our CHF and SED groups. In contrast, enzymes involved in energy transfer and substrate utilization were specifically diminished in our CHF group (total and MM-CK, total LDH). This is at first surprising since a higher amount of these two enzymes is normally present in fast glycolytic and deconditioned muscles (15). However, this is reminiscent of what was observed in the failing myocardium of humans and animals (14,20) and in the oxidative muscle of rats with CHF (8) and may be a hallmark of CHF. On the other hand, compared with the SED group, CS activity was lower in patients with CHF and higher in the ACT group in accordance with many studies (6,7).

Potential mechanisms for the abnormal skeletal muscle metabolism in CHF.   Taken together, our results of maintained oxidative capacity in CHF require three considerations. First, the fact that the concentration or activity of several enzymes of the Krebs cycle and of certain electron transport chain complexes like the cytochrome oxidase (21) have been found lowered in skeletal muscle from patients with CHF does not imply a decreased overall oxidative function since mitochondria are functioning well above their limitation threshold for most of their enzymatic complexes (22), in line with the cytochrome oxidase excess already largely documented (23). A limitation at the level of the Krebs cycle is an unlikely explanation despite the decrease in CS we and others found (6,24) because neither CS nor the Krebs cycle are rate-controlling mitochondrial respiration (22,25). Indeed, numerous extra-mitochondrial reasons also explain the high-energy phosphate abnormalities in CHF. High-energy phosphate abnormalities observed in CHF skeletal muscle may result from intrinsic or extrinsic factors (1–3,24). The decreased capillary density and endothelium-dependent vasodilation may cause uneven distribution of blood flow within the muscle and a decrease in cellular oxygen and substrate supply (1,11). Moreover, the reduced muscle mass and the fiber type distribution changes result in a greater type II fiber recruitment for a given work rate (2,9). This leads to early intracellular acidosis and excess tissue NO due to the increased inducible NO synthase and might contribute to a decreased mitochondrial ATP production, which is not seen in the respiration chamber (10,26). Indeed, excess NO has already been demonstrated to decrease mitochondrial function in isolated mitochondria (26) and within heart tissue (27). This may also be the case for skeletal muscle since the inducible NO synthase activity has been found to increase in patients with CHF (10). Second, oxidative capacity in muscle is influenced by deconditioning. Duscha et al. (11) emphasized the need to compare patients with CHF to truly sedentary controls. Such comparison allowed us to separate the deconditioning-related changes (the mitochondrial intrinsic oxidative capacity) from the CHF-specific ones (the enzymatic changes that are opposite to the ones expected from a shift to a faster muscle phenotype) and to evidence similar intrinsic mitochondrial function in CHF and SED. This is in line with the absence of skeletal muscle high-energy phosphate abnormalities in the only study comparing patients with CHF to truly sedentary controls (28). This, again, favors the hypothesis that CHF-specific metabolic abnormalities are mostly of extramitochondrial origin. The functional counterpart of these specific changes might be a decreased high-energy phosphate transfer within the muscle cell during exercise, as was already suggested to happen in failing myocardium (20). Third, pharmacotherapy might contribute to the differences between previous studies and our findings. In experimental CHF in untreated animals (8), we have recently described alterations in oxidative capacity and mitochondrial regulation as well as a shift of the soleus towards a more fast-glycolytic phenotype. In humans, Drexler et al. (1), using ultrastructural morphometry, suggested that the mitochondrial oxidative capacity was impaired in CHF. Of note, only 26% of their patients took ACE inhibitors, whereas all of ours did. It is now clearly established that ACE inhibitors have a direct beneficial effect on cardiac remodeling and energy metabolism (29); ACE inhibitors have also been shown to protect the skeletal muscle from structural alterations in models of CHF (30,31), to correct abnormal MHC profiles in both animals and patients (19,31) and to increase oxygen consumption and skeletal muscle blood flow at exercise (32). Together with their beneficial effects on exercise capacity, ACE inhibitors also correct the energetic efficiency of the skeletal muscle contractile machinery and protect against some energy wasting mechanisms set by heart failure (31).

Mechanisms of exercise limitation in CHF.   Our findings suggest that in patients with CHF the maximal oxidative capacity of the skeletal muscle mitochondria exceeds the maximal exercise-induced muscle VO2. Thus, their abnormal muscle metabolism should mainly result from mechanisms upstream from the mitochondria. This is further exemplified by the disruption of the normal relationship between the parameters of mitochondrial function and of exercise capacity (Fig. 4). The VO2max limitation involves the succession of many steps controlling the delivery and utilization of oxygen starting from lung capacity, cardiac pump function, vascular content and resistance and ending at the level of mitochondrial respiration. In normal animals and humans, it is accepted that, during exercise involving a large muscle mass, the absolute limit to VO2max lies in the O2 supply to the mitochondria rather than in its O2 demand and that the relative importance of each step may vary depending on the degree of fitness (33–35). According to the general concept of symmorphosis, there is no real excess capacity for one step (except lung capacity) but rather a close matching between functional and structural design at each level (36). This suggests a sharing of the overall control of oxygen consumption by each step. Indeed, skeletal muscle (36) and heart tissue (37) utilize 80% to 90% of their maximal mitochondrial VO2 at peak exercise. This is illustrated by the correlation we found between muscle oxidative capacity and peak or VT VO2 in controls. The similar trend in patients, although shifted towards the lower peak VO2 values, further suggests a restriction upward from the mitochondria. Thus, pathology, in our case CHF, can disrupt the normal structure and function relationship by inducing limitations within the oxygen and substrate cascade at levels that do not normally operate. Because Chomsky et al. (38) have shown that only a subset of patients with severe CHF have a diminished cardiac output for a given work rate, the abnormal convective O2 transport may also result from a defect in blood flow redistribution, in the microvasculature or in the diffusion from the capillary to the cell (1,2,11). Although further studies are needed to explore these hypotheses, the fact that the skeletal muscle intrinsic mitochondrial function is preserved in patients with CHF treated with ACE inhibitors indicates that further improvements may be expected from therapeutic advances because the microvascular functional alterations are more accessible to interventions than intrinsic structural defects.

Conclusions.   Having found similar intrinsic ADP-stimulated respiratory features in the skeletal muscle of patients with severe CHF and SED controls, we conclude that, in patients with CHF adequately treated with long-term ACE inhibitors, the exercise metabolic impairment of the skeletal muscle results mostly from deconditioning and factors upstream from the mitochondria that either decrease the availability of oxygen and substrates or alter the mitochondrial environment during exercise. All these factors might combine their deleterious effects to decrease exercise capacity.


   Acknowledgments
 
We thank Professors B. Eisenmann and J. G. Kretz and Dr. R. Fischmeister for continuous encouragement and our patients and control subjects for their enthusiastic participation.


   Footnotes
 
Supported by grants from the INSERM-PROGRES and AFM programs. Dr. Ventura-Clapier is supported by the "Centre National de la Recherche Scientifique."


   References
Top
 Abstract
 Methods
 Results
 Discussion
 References
 

  1. Drexler H, Riede U, Münzel T, König H, Funke E, Just H. Alterations of skeletal muscle in chronic heart failure. Circulation. 1992;85:1751–1759[Abstract/Free Full Text]
  2. Clark AL, Poole-Wilson PA, Coats AJS. Exercise limitation in chronic heart failure: central role of the periphery. J Am Coll Cardiol. 1996;28:1092–1102[Abstract]
  3. Massie BM, Conway M, Rajagopalan B, et al. Skeletal muscle metabolism during exercise under ischemic conditions in congestive heart failure: evidence for abnormalities unrelated to blood flow. Circulation. 1988;78:320–326[Abstract/Free Full Text]
  4. Mancini DM, Wilson JR, Bollinger L, et al. In vivo magnetic resonance spectroscopy measurement of deoxymyoglobin during exercise in patients with heart failure: demonstration of abnormal muscle metabolism despite adequate oxygenation. Circulation. 1994;90:500–508[Abstract/Free Full Text]
  5. Sullivan MJ, Knight DJ, Higginbotham MB, Cobb FR. Relation between central and peripheral hemodynamics during exercise in patients with chronic heart failure: muscle blood flow is reduced with maintenance of arterial perfusion pressure. Circulation. 1989;80:769–781[Abstract/Free Full Text]
  6. Sullivan MJ, Green HJ, Cobb FR. Skeletal muscle biochemistry and histology in ambulatory patients with long-term heart failure. Circulation. 1990;81:518–527[Abstract/Free Full Text]
  7. Opasich C, Aquilani R, Dossena M, et al. Biochemical analysis of muscle biopsy in overnight fasting patients with severe heart failure. Eur Heart J. 1996;17:1686–1693[Abstract/Free Full Text]
  8. De Sousa E, Veksler V, Bigard X, Mateo P, Ventura-Clapier R. Heart failure affects mitochondrial but not myofibrillar intrinsic properties of skeletal muscle. Circulation. 2000;102:1847–1853[Abstract/Free Full Text]
  9. Massie BM, Simonini A, Sahgal P, Wells L, Dudley GA. Relation of systemic and local muscle exercise capacity to skeletal muscle characteristics in men with congestive heart failure. J Am Coll Cardiol. 1996;27:140–145[Abstract]
  10. Hambrecht R, Adams V, Gielen S, et al. Exercise intolerance in patients with chronic heart failure and increased expression of inducible nitric oxide synthase in the skeletal muscle. J Am Coll Cardiol. 1999;33:174–179[Abstract/Free Full Text]
  11. Duscha BD, Kraus WE, Keteyian SJ, et al. Capillary density of skeletal muscle: a contributing mechanism for exercise intolerance in class II to III chronic heart failure independent of other peripheral alterations. J Am Coll Cardiol. 1999;33:1956–1963[Abstract/Free Full Text]
  12. Saks VA, Veksler VI, Kuznetsov AV, et al. Permeabilized cell and skinned fiber techniques in studies of mitochondrial function in vivo. Mol Cell Biochem. 1998;184:81–100[CrossRef][Medline]
  13. Wasserman K, Hansen JE, Sue DY, Whipp BJ, Casaburi R. Principles of Exercise Testing and Interpretation. 2nd edition. Philadelphia, PA: Lea and Febiger; 1994.
  14. De Sousa E, Veksler V, Minajeva A, et al. Subcellular creatine kinase alterations: implications in heart failure. Circ Res. 1999;85:68–76[Abstract/Free Full Text]
  15. Bigard AX, Boehm E, Veksler V, Mateo P, Anflous K, Ventura-Clapier R. Muscle unloading induces slow to fast transitions in myofibrillar but not mitochondrial properties: relevance to skeletal muscle abnormalities in heart failure. J Mol Cell Cardiol. 1998;30:2391–2401[CrossRef][Medline]
  16. Veksler VI, Kuznetsov AV, Anflous K, et al. Muscle creatine kinase deficient mice: cardiac and skeletal muscles exhibit tissue-specific adaptation of the mitochondrial function. J Biol Chem. 1995;270:19921–19929[Abstract/Free Full Text]
  17. Tonkonogi M, Harris B, Sahlin K. Mitochondrial oxidative function in human saponin-skinned muscle fibers: effects of prolonged exercise. J Physiol (London). 1998;510:279–286[Abstract/Free Full Text]
  18. Kay L, Nicolay K, Wieringa B, Saks V, Walliman T. Direct evidence for the control of mitochondrial respiration by mitochondrial creatine kinase in oxidative muscle cells in situ. J Biol Chem. 2000;275:6937–6944[Abstract/Free Full Text]
  19. Vescovo G, Dalla Libera L, Serafini F, et al. Improved exercise tolerance after Losartan and Enalapril in heart failure: correlation with changes in skeletal muscle myosin heavy chain composition. Circulation. 1998;98:1742–1749[Abstract/Free Full Text]
  20. Nascimben L, Ingwall JS, Pauletto P, et al. Creatine kinase system in failing and nonfailing human myocardium. Circulation. 1996;94:1894–1901[Abstract/Free Full Text]
  21. Hambrecht R, Niebauer J, Fiehn E, et al. Physical training in patients with stable chronic heart failure: effects on cardiorespiratory fitness and ultrastructural abnormalities of leg muscles. J Am Coll Cardiol. 1995;25:1239–1249[Abstract]
  22. Letellier T, Heinrich R, Malgat M, Mazat JP. The kinetic basis of the threshold effects observed in mitochondrial diseases: a systemic approach. Biochem J. 1994;302:171–174[Medline]
  23. Gnaiger E, Lassnig B, Kuznetsov A, Rieger G, Margreiter R. Mitochondrial oxygen affinity, respiratory flux control and excess capacity of cytochrome c oxidase. J Exp Biol. 1998;201:1129–1139[Abstract]
  24. Mancini DM, Coyle E, Coggan A, et al. Contribution of intrinsic skeletal muscle changes to 31P NMR skeletal muscle metabolic abnormalities in patients with chronic heart failure. Circulation. 1989;80:1338–1346[Abstract/Free Full Text]
  25. Blomstrand E, Radegran G, Saltin B. Maximum rate of oxygen uptake by human skeletal muscle in relation to maximal activities of enzymes in the Krebs cycle. J Physiol (London). 1997;501:455–460[Abstract/Free Full Text]
  26. Okada S, Takehara Y, Yabuki M, Yoshioka T, Inoue M, Utsumi K. Nitric oxide, a physiological modulator of mitochondrial function. Physiol Chem Med NMR. 1996;28:69–82
  27. Loke KE, Laycock SK, Mital S, et al. Nitric oxide modulates mitochondrial respiration in failing human heart. Circulation. 1999;100:1291–1297[Abstract/Free Full Text]
  28. Chati Z, Zannad F, Jeandel C, et al. Physical deconditioning may be a mechanism for the skeletal muscle energy phosphate metabolism abnormalities in chronic heart failure. Am Heart J. 1996;131:560–566[CrossRef][Medline]
  29. Hügel S, Horn M, De Groot M, et al. Effects of ACE inhibition and beta-receptor blockade on energy metabolism in rats postmyocardial infarction. Am J Physiol. 1999;277:H2167–H2175[Medline]
  30. Schieffer B, Wollert KC, Berchtold M, et al. Development and prevention of skeletal muscle structural alterations after experimental myocardial infarction. Am J Physiol. 1995;269:H1507–H1513[Medline]
  31. Yamaguchi F, Kawana K, Tanonaka K, et al. Improvement of exercise capacity of rats with chronic heart failure by long-term treatment with trandolapril. Br J Pharmacol. 1999;126:1585–1592[CrossRef][Medline]
  32. Drexler H, Banhardt U, Meinertz T, Wollschläger H, Lehmann M, Just H. Contrasting peripheral short-term and long-term effects of converting enzyme inhibition in patients with congestive heart failure. Circulation. 1989;79:491–502[Abstract/Free Full Text]
  33. Davies KJA, Packer L, Brooks GA. Biochemical adaptations of mitochondria, muscle and whole animal respiration to endurance training. Arch Biochem Biophys. 1981;209:539–554[CrossRef][Medline]
  34. Richardson RS, Harms CA, Grassi B, Hepple RT. Skeletal muscle: master or slave of the cardiovascular system? Med Sci Sports Exerc. 2000;32:89–93
  35. Richardson RS, Noyszewski EA, Kendrick KF, Leigh JS, Wagner PD. Myoglobin O2 desaturation during exercise: evidence of limited O2 transport. J Clin Invest. 1995;96:1916–1926[Medline]
  36. Schwertzmann K, Hoppeler H, Kayar SR, Weibel ER. Oxidative capacity of muscle and mitochondria: correlation of physiological, biochemical and morphometric characteristics. Proc Nat Acad Sci. 1989;86:1583–1587[Abstract/Free Full Text]
  37. Mootha V, Arai AE, Balaban RS. Maximum oxidative phosphorylation capacity of the mammalian heart. Am J Physiol. 1997;272:H769–H775[Medline]
  38. Chomsky DB, Lang CC, Rayos G, et al. Hemodynamic exercise testing: a valuable tool in the selection of cardiac transplantation candidates. Circulation. 1996;94:3176–3183[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
A. Mezzani, U. Corra, C. Andriani, A. Giordano, R. Colombo, and P. Giannuzzi
Anaerobic and aerobic relative contribution to total energy release during supramaximal effort in patients with left ventricular dysfunction
J Appl Physiol, January 1, 2008; 104(1): 97 - 102.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
B. Roels, C. Thomas, D. J. Bentley, J. Mercier, M. Hayot, and G. Millet
Effects of intermittent hypoxic training on amino and fatty acid oxidative combustion in human permeabilized muscle fibers
J Appl Physiol, January 1, 2007; 102(1): 79 - 86.
[Abstract] [Full Text] [PDF]

Home page
 Cardiovasc ResHome page
R. Ventura-Clapier, B. Mettauer, and X. Bigard
Beneficial effects of endurance training on cardiac and skeletal muscle energy metabolism in heart failure
Cardiovasc Res, January 1, 2007; 73(1): 10 - 18.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
J. Zoll, L. Monassier, A. Garnier, B. N'Guessan, B. Mettauer, V. Veksler, F. Piquard, R. Ventura-Clapier, and B. Geny
ACE inhibition prevents myocardial infarction-induced skeletal muscle mitochondrial dysfunction
J Appl Physiol, August 1, 2006; 101(2): 385 - 391.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
M. Eimre, R. Puhke, K. Alev, E. Seppet, A. Sikkut, N. Peet, L. Kadaja, A. Lenzner, T. Haviko, T. Seene, et al.
Altered mitochondrial apparent affinity for ADP and impaired function of mitochondrial creatine kinase in gluteus medius of patients with hip osteoarthritis
Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2006; 290(5): R1271 - R1275.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
K. Guerrero, B. Wuyam, P. Mezin, I. Vivodtzev, M. Vendelin, J.-C. Borel, R. Hacini, O. Chavanon, S. Imbeaud, V. Saks, et al.
Functional coupling of adenine nucleotide translocase and mitochondrial creatine kinase is enhanced after exercise training in lung transplant skeletal muscle
Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2005; 289(4): R1144 - R1154.
[Abstract] [Full Text] [PDF]

Home page
 FASEB J.Home page
A. Garnier, D. Fortin, J. Zoll, B. N'Guessan, B. Mettauer, E. Lampert, V. Veksler, and R. Ventura-Clapier
Coordinated changes in mitochondrial function and biogenesis in healthy and diseased human skeletal muscle
FASEB J, January 1, 2005; 19(1): 43 - 52.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
C. Thomas, P. Sirvent, S. Perrey, E. Raynaud, and J. Mercier
Relationships between maximal muscle oxidative capacity and blood lactate removal after supramaximal exercise and fatigue indexes in humans
J Appl Physiol, December 1, 2004; 97(6): 2132 - 2138.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
R. Ventura-Clapier, A. Garnier, and V. Veksler
Energy metabolism in heart failure
J. Physiol., February 15, 2004; 555(1): 1 - 13.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
L. Bahi, N. Koulmann, H. Sanchez, I. Momken, V. Veksler, A. X. Bigard, and R. Ventura-Clapier
Does ACE inhibition enhance endurance performance and muscle energy metabolism in rats?
J Appl Physiol, January 1, 2004; 96(1): 59 - 64.
[Abstract] [Full Text] [PDF]

Home page
 J Am Coll CardiolHome page
J. Zoll, B. N'Guessan, F. Ribera, E. Lampert, D. Fortin, V. Veksler, X. Bigard, B. Geny, J. Lonsdorfer, R. Ventura-Clapier, et al.
Preserved response of mitochondrial function to short-term endurance training in skeletal muscle of heart transplant recipients
J. Am. Coll. Cardiol., July 2, 2003; 42(1): 126 - 132.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Respir. Crit. Care Med.Home page
F. Ribera, B. N'Guessan, J. Zoll, D. Fortin, B. Serrurier, B. Mettauer, X. Bigard, R. Ventura-Clapier, and E. Lampert
Mitochondrial Electron Transport Chain Function Is Enhanced in Inspiratory Muscles of Patients with Chronic Obstructive Pulmonary Disease
Am. J. Respir. Crit. Care Med., March 15, 2003; 167(6): 873 - 879.
[Abstract] [Full Text] [PDF]

Home page
 Cardiovasc ResHome page
E. De Sousa, P. Lechene, D. Fortin, B. N'Guessan, S. Belmadani, X. Bigard, V. Veksler, and R. Ventura-Clapier
Cardiac and skeletal muscle energy metabolism in heart failure: beneficial effects of voluntary activity
Cardiovasc Res, November 1, 2002; 56(2): 260 - 268.
[Abstract] [Full Text] [PDF]

Home page
 PhysiologyHome page
R. Ventura-Clapier, E. De Sousa, and V. Veksler
Metabolic Myopathy in Heart Failure
Physiology, October 1, 2002; 17(5): 191 - 196.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mettauer, B.
Right arrow Articles by Ventura-Clapier, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mettauer, B.
Right arrow Articles by Ventura-Clapier, R.

HOME SUBSCRIPTIONS CURRENT ISSUE PAST ISSUES CARDIOSOURCE SEARCH HELP FEEDBACK