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Segmental cytochrome c ‐oxidase deficiency in CPEO: Teased muscle fiber analysis
Author(s) -
Matsuoka Taro,
Goto YuIchi,
Hasegawa Hitomi,
aka Ikuya
Publication year - 1992
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/mus.880150213
Subject(s) - cytochrome c oxidase , medicine , physical medicine and rehabilitation , anatomy , biology , mitochondrion , genetics
In an attempt to elucidate the pathogenesis of focal cytochrome c‐oxidase (COX) deficiency in skeletal muscle from patients with chronic progressive external ophthalmoplegia (CPEO), we examined the longitudinal distribution of COX activity in single muscle fibers from 6 CPEO patients with muscle mitochondrial DNA (mtDNA) deletions. A new method for teasing single muscle fibers, recently developed in our laboratory, revealed fibers with COX‐positive and ‐negative segments in all 6 patients. The borders between the enzyme‐positive and ‐negative segments in these fibers were sharply delineated, so that the length of each COX‐negative segments could be accurately measured. The proportion of the sum of the lengths of the enzyme‐negative segments to the total length of the muscle fibers correlated well with the proportion of deleted mtDNA, suggesting that abnormal mitochondria harboring mutant mtDNA may be responsible for the focal loss of COX activity.