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Overexpression of calcineurin increases skeletal muscle capillarization
Author(s) -
Davanzo M J,
Jensen E B,
Dohm G L,
BasselDuby R,
Gavin T P
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1302-b
Subject(s) - skeletal muscle , fiber type , chemistry , calcineurin , endocrinology , fiber , oxidative phosphorylation , muscle fibre , medicine , skeletal muscle fibers , anatomy , biology , biochemistry , transplantation , organic chemistry
Skeletal muscle is heterogenic in nature such that one muscle contains several different muscle fiber types including I, IIA, and IIB fiber types. There are significant differences between muscle fiber types such that type I fibers demonstrate greater oxidative capacity and capillarization compared to type IIB fibers. Calcium, working through calcineurin (CaN), is a key determinant of muscle fiber type, such that overexpression of CaN increases the number of oxidative muscle fibers. We hypothesized that CaN also regulates skeletal muscle capillarization. At 10‐weeks of age, the plantaris muscle of wild‐type (WT) (N=6) and CaN (N=7) overexpressing (MCK‐CN) mice was removed for the measurement of fiber type specific muscle capillarization. Preliminary data suggest that the number of capillaries per fiber (C/F) was greater in type IIA fibers (WT: 1.3 ± 0.1 vs. MCK‐CN: 1.8 ± 0.1) and tended to be greater in type I muscle fibers of MCK‐CN compared to WT (WT: 1.8 ± 0.1 vs. MCK‐CN: 2.2 ± 0.2). There was no difference in type IIB fibers (WT: 2.0 ± 0.1 vs. MCK‐CN: 2.0 ± 0.1). In conclusion, our preliminary data suggest that overexpression of CaN increases skeletal muscle capillarization of oxidative muscle fibers (type I and IIA). Supported by NIH AG‐21891, Mid‐Atlantic AHA 0465415U, and NIH DK‐38416.