| Popis: |
Introduction: Sarcopenia is a term for the loss of skeletal muscle mass, quality and performance associated with normal aging that can lead to frailty in the elderly. Contributing to physical frailty are skeletal muscle atrophy, declining strength, increasing fatigability and susceptibility to injury. For healthy elderly persons, the decrease in muscle mass results from a loss in the total number of fibers per muscle as well as a decrease in the mean cross sectional area of the remaining fibers. The aim of this study was to determine age-related changes in three human muscles with different function and location in the body. Materials and methods: The cross sectional area and the percentage of fibers type I, type IIA and type IIX were studied in vastus lateralis, deltoid and external intercostal muscle. Muscle samples were obtained from 30 male subjects, aged 20–80 years. Fiber types were defined immunohistochemically, using monoclonal antibodies specific for each type of fibers. Results: All muscle fiber types showed the reduction in the fiber size in all three examined muscles. In all muscles the proportion of type I and type IIA was changed, but not in type IIX. With increasing age results showed the increase in proportion of type I, while proportion of type IIA fibers decreased, with vastus lateralis muscle being the most affected. Conclusions: These results suggest that age-related muscle atrophy is not a general phenomenon, and does not affect all muscles equally. |
