Document Detail


Exercise intolerance in patients with McArdle's disease or mitochondrial myopathies.
MedLine Citation:
PMID:  1341204     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES: To assess respiratory and metabolic adaptations in patients with phosphorylase deficiency and mitochondrial myopathies using maximal exercise tests. PATIENTS AND METHODS: Five patients with McArdle's disease and five patients with mitochondrial myopathies performed the same incremental maximal exercise test. Their respiratory gas exchanges and the variation of the venous blood metabolites--lactate (LACT), pyruvate (PYR), alanine (ALA), ammonia (NH3)--were studied in comparison with the results of fourteen control subjects who performed the same test. RESULTS: Compared with controls, the two groups of patients displayed a similar significant decrease of their maximal VO2. In McArdle's patients the limitation of the maximal oxygen consumption was associated with a low respiratory exchange ratio (RER), a high VE/VO2, and characteristic metabolic data: no rise of LACT and PYR, a decrease of ALA and an important rise of NH3. In mitochondrial myopathies low VO2 max were due to a leftwards shift, i.e. towards low powers of exercise, of LACT, PYR, NH3 and ALA values. However the pattern of increase of LACT, PYR and NH3, exponential, and of ALA, linear, as well as respiratory exchange ratios were similar to control values. In this case, the limitation of oxygen consumption was due to a lack of the usual substrate, pyruvate. Low respiratory exchange ratio demonstrated that the muscle metabolism had a tendency to shift to lipid oxidation. CONCLUSION: These results suggest that patients with McArdle's disease may improve their muscle energy production by endurance training which enhances lipid metabolism, whereas in mitochondrial myopathies, the energy production by oxidation of pyruvate or lipids may be improved only by enzymatic substitution.
Authors:
M Chaussain; F Camus; C Defoligny; B Eymard; M Fardeau
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  The European journal of medicine     Volume:  1     ISSN:  1165-0478     ISO Abbreviation:  Eur J Med     Publication Date:  1992 Dec 
Date Detail:
Created Date:  1994-01-13     Completed Date:  1994-01-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9209793     Medline TA:  Eur J Med     Country:  FRANCE    
Other Details:
Languages:  eng     Pagination:  457-63     Citation Subset:  IM    
Affiliation:
Laboratoire d'Explorations Fonctionnelles Respiratoires, Hôpital Saint-Vincent-de-Paul, Paris, France.
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MeSH Terms
Descriptor/Qualifier:
Adult
Alanine / blood
Ammonia / blood
Energy Metabolism / physiology
Exercise Test
Exercise Tolerance / physiology*
Female
Glycogen Storage Disease Type V / physiopathology*
Humans
Lactates / blood
Lactic Acid
Male
Mitochondrial Myopathies / physiopathology*
Muscle Contraction / physiology*
Muscles / metabolism,  physiopathology*
Oxygen Consumption / physiology
Pulmonary Gas Exchange / physiology
Pyruvates / blood
Pyruvic Acid
Chemical
Reg. No./Substance:
0/Lactates; 0/Pyruvates; 127-17-3/Pyruvic Acid; 50-21-5/Lactic Acid; 56-41-7/Alanine; 7664-41-7/Ammonia
Comments/Corrections
Comment In:
Eur J Med. 1992 Dec;1(8):453-6   [PMID:  1341203 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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