Muscle fibre size and shape in Duchenne muscular dystrophy

A method for measuring fibre area and shape which obviates variabilities inherent in diameter measuring techniques was applied to dystrophic and normal human muscle. It was seen that the mean fibre area in patients with Duchenne muscular dystrophy (DMD) increases with age at a greater rate than that of the controls until approximately 5 years-of-age, when it decreases rapidly. This is due to an increasing population of small regenerating, regenerated or split fibres. The shape of fibres was expressed as a form factor and it was seen that the fibres measured from DMD biopsies were less regular in shape than the controls due to constraints placed on the normal growth of regenerating fibres by the proliferation of connective tissue.