Changes in human skeletal muscles due to ageing

Abstract

Morphological changes in human skeletal muscle with ageing are reported. Samples from the deltoid and the vastus lateralis muscles from 126 subjects, aged 20-80 years, were studied by light microscopy. The patients died suddenly due to accidents or from fatal diseases. Until their death, they had preserved normal physical activity corresponding to their age. Chronic diseases, inactivity or neuromuscular diseases which are known to lead to changes in the muscles were excluded. The frequency of neurogenic changes of muscles increased with increasing age. These results correlated with electrophysiological and morphological changes in the peripheral nerves due to ageing reported by other investigators. The neurogenic changes in persons over 70 years were overlapped by a type-2 fibre atrophy.

Skeletal muscle fatigue and physical endurance of young and old mice

“…7 Histochemical analysis of the aged muscles revealed a preferential atrophy of type II (fast-twitch readily fatigable glycolytic) muscle fibers and grouping of type I muscle fibers. 28,35 While such a change in the fiber type composition can account for the slight increase in resistance to fatigue in old EDL, it may not account for the marked increase in resistance to fatigue in old soleus as observed in the present study. A similar increase in resistance to fatigue, without a comparable increase in slow-twitch oxidative fibers, was observed in muscles of the dystrophic mice, 46 especially in the soleus of the dystrophic mice, 42 and in denervated soleus of normal mice.…”

Morphometrical Analysis of Skeletal Muscle Fibre Ageing and the Effect of Hypophysectomy and Food Restriction in the Rat

“…These include the presence of small fibres in distinct groups characteris tic of neurogenic atrophy and groupings of specific fibre types, a feature resulting from re-innervation of denervated muscle fibres [Tomlinson et al, 1969;Jennekens et al, 1971;Rebeiz et al, 1972;Fujisawa, 1974;Caccia et al, 1979], An interesting physiological feature of ageing muscles is the increase in slow-twitch motor units, suggesting that the ageing pro cess affects fast-twitch motor units more se verely [Campbell et al, 1973], although the possibility that fast-twitch (type 2) fibres convert to slow-twitch (type 1) fibres has also been suggested [Caccia et al, 1979]. Histo logically, a greater atrophy of fast-twitch fibres than slow-twitch fibres has been re ported in humans [Tomonaga, 1977;Orlander et al, 1978;Larsson, 1978;Oertel, 1986], and animal muscles [Gutmann and Hanzlikova, 1972], Long-term food restriction is able to re tard many morphological age changes in skeletal muscle of the rat [Berg and Simms, 1961;McCarter et al, 1982;Yu et al, 1982;Everitt et al, 1985] and to inhibit the devel opment of hind-limb paralysis in old age [Berg and Simms, 1961;Everitt et al, 1980Everitt et al, , 1985. Everitt et al [1980Everitt et al [ , 1985 found that the development of hind-limb paralysis in old age and the accompanying atrophy and de generation of the gastrocnemius muscle in the hind legs did not occur following hypophysectomy in early life.…”

“…Lexell et al [1985] detailed the sampling errors arising from the use of a single muscle biopsy. There appears to be no previous studies in the rat concerned with age changes in muscle fibre size according to type, although this is welldocumented in human muscles [Oertel, 1986],…”

Proportions of fiber types in the external urethral sphincter of young nulliparous and old multiparous rabbits

“…Glycerinated muscle fibers were dissected out from these sections in RB on crushed ice It is generally considered that genuine stress incontinence is more common among old multiparous women than among young nulliparous women [5]. Recent studies show that loss of strength and atrophy of human skeletal muscle with aging are attributable to selective atrophy of type 2 (fast) muscle fibers [1,15,18]. The present study was designed to examine the difference in the proportions of fast and slow myosin molecules in the external urethral sphincter (EUS) between young nulliparous and old multiparous female rabbits.…”