Skeletal muscle mitochondrial function in polymyalgia rheumatica and in giant cell arteritis.
OBJECTIVE
To ascertain whether mitochondrial function is impaired in polymyalgia rheumatica (PMR) and giant cell arteritis (GCA).


METHODS
Thirteen patients suffering from isolated PMR, 19 from GCA (eight with and 11 without PMR) and 25 healthy people submitted to orthopaedic surgery were included. Skeletal muscle was obtained from the quadriceps by open biopsy. Mitochondrial histological abnormalities were assessed on Gomori's trichrome staining and on cytochrome c oxidase and succinic dehydrogenase reactions. Biochemical studies consisted of polarographic measurement of oxidative activity using complex I, II, III and IV substrates, and spectrophotometric determination of individual enzymatic activity of such complexes.


RESULTS
We did not find differences among groups either with respect to the percentage of histological or histochemical abnormalities [P = not significant (NS) for all stainings and reactions], oxidative capacity (P = NS for all substrates) or individual enzymatic activities (P = NS for all complexes).


CONCLUSIONS
Skeletal muscle mitochondria remain histologically and functionally unaffected in PMR and in GCA.
Department of Internal Medicine, Hospital Clínic, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Medical School, University of Barcelona, Catalonia, Spain.
O
O
Miró
J
J
Casademont
D
D
Jarreta
J M
JM
Grau
A
A
Urbano-Márquez
F
F
Cardellach
D000368:Aged; D004579:Electron Transport; D005260:Female; D013700:Giant Cell Arteritis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D011111:Polymyalgia Rheumatica / Q000503:physiopathology*