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Residual muscle cytochrome c oxidase activity accounts for submaximal exercise lactate threshold in chronic progressive external ophthalmoplegia
Author(s) -
Siciliano Gabriele,
Rossi Bruno,
Manca Laura,
Angelini Corrado,
Tessa Alessandra,
Vergani Lodovica,
Martinuzzi Andrea,
Muratorio Alberto
Publication year - 1996
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199603)19:3<342::aid-mus10>3.0.co;2-u
Subject(s) - chronic progressive external ophthalmoplegia , cytochrome c oxidase , medicine , skeletal muscle , endocrinology , mitochondrial myopathy , muscle biopsy , biology , mitochondrion , chemistry , biopsy , mitochondrial dna , biochemistry , gene
The data from histological, biochemical, and mitochondrial DNA (mtDNA) studies of muscle biopsies from 10 patients affected with chronic progressive external ophthalmoplegia (CPEO) were related to dynamic and metabolic parameters of incremental submaximal exercise. Maximum power output was reduced in all patients as compared to controls. Analysis of the venous lactate curve during exercise revealed a lactate threshold at exercise levels ranging from 40 to 50% of the predicted maximal power output. An earlier significant increase in lactate could be detected by calculating the mean δ lactate. Lactate values were inversely correlated with the cytochrome c oxidase (COX) activity of isolated muscle mitochondria. No relationship was found between lactate values and the number of ragged red fibers, or cytochrome c oxidase‐negative fibers or the proportion of deleted mtDNA measured in muscle biopsy specimens. The discussion underscores the value of lactate kinetics in assessing skeletal muscle function, as well as the use of muscle COX levels to predict the effectiveness of wild‐type complementation of deleted skeletal muscle mtDNA in in vivo contractile performance of CPEO subjects. © 1996 John Wiley & Sons, Inc.