Is the myonuclear domain size fixed?

S.F.T. Van der Meer (1,2,*), R.T. Jaspers (3), H. Degens (1,2)

(1) Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, John Dalton Building, Chester Street, Manchester M1 5GD, United Kingdom;
(2) Institute of Aerospace Medicine, Division Space Physiology, German Aerospace Center, Cologne, Germany;
(3) Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands
* deceased 28 July 2010

Abstract
It has been suggested that the number of myonuclei in a muscle fibre changes in proportion to the change in fibre size, resulting in a constant myonuclear domain size, defined as the cytoplasmic volume per myonucleus. The myonuclear domain size varies, however, between fibre types and is inversely related with the oxidative capacity of a fibre. Overall, the observations of an increase in myonuclear domain size during both maturational growth and overload-induced hypertrophy, and the decrease in myonuclear domain size during disuse- and ageing-associated muscle atrophy suggest that the concept of a constant myonuclear domain size needs to be treated cautiously. It also suggests that only when the myonuclear domain size exceeds a certain threshold during growth or overload-induced hypertrophy acquisition of new myonuclei is required for further fibre hypertrophy.

Keywords: Skeletal Muscle, Myonuclear Domain, Satellite Cell, Hypertrophy, Atrophy, Ageing, Growth