Sarcopenia is the age-associated loss of skeletal muscle mass and function which happens in upper (UL) as in lower limbs (LL) being still unclear the relation between muscles functions and daily activities (i.e. independently walking or not). We studied the changes linked to age and disuse in very old women. Contractile properties of whole muscles and isolated single fibres from UL (biceps brachii) and LL (vastus lateralis) were measured in 10 elderly women (90-100 y) divided in two subgroups on the basis of regular mobility: usually walking (E-W) II– usually moving by wheel chair (E-NW). Five young women (Y: 20-30 y) were used as controls. The following parameters were determined in single fibres: cross sectional area (CSA), isometric force (Fo), and MHC isoforms composition; in the whole muscles: lean mass and maximal isometric strength. Single fibre measurements showed: similar degree of atrophy in the EW and E-NW vs.Y; no changes in Fo; a significant age-related increase in slow fibres more pronounced in E-W. Whole muscles testing demonstrate: lower lean mass and strength in E groups vs Y. No changes in UL between aged groups (0.84±0.03 vs 0.86±0.04 kg/m2; 18±10, and 21±8Nm; E-NW vs E-W). Reduced lean mass and torque in the LL in the non walking (2.58±0.04 vs 3.20±0.04 kg/m2 41±19 vs 64±20Nm; E-NW vs E-W p<0,05). Our data demonstrate that age-related sarcopenia results in overall lower muscle mass while contractile function seems to be more affected by daily utilization.

Sarcopenia in very old women: interaction of aging and disuse on muscle function decline

VENTURELLI, Massimo;TARPERI, Cantor;CALABRIA, Elisa;SCHENA, Federico
2012

Abstract

Sarcopenia is the age-associated loss of skeletal muscle mass and function which happens in upper (UL) as in lower limbs (LL) being still unclear the relation between muscles functions and daily activities (i.e. independently walking or not). We studied the changes linked to age and disuse in very old women. Contractile properties of whole muscles and isolated single fibres from UL (biceps brachii) and LL (vastus lateralis) were measured in 10 elderly women (90-100 y) divided in two subgroups on the basis of regular mobility: usually walking (E-W) II– usually moving by wheel chair (E-NW). Five young women (Y: 20-30 y) were used as controls. The following parameters were determined in single fibres: cross sectional area (CSA), isometric force (Fo), and MHC isoforms composition; in the whole muscles: lean mass and maximal isometric strength. Single fibre measurements showed: similar degree of atrophy in the EW and E-NW vs.Y; no changes in Fo; a significant age-related increase in slow fibres more pronounced in E-W. Whole muscles testing demonstrate: lower lean mass and strength in E groups vs Y. No changes in UL between aged groups (0.84±0.03 vs 0.86±0.04 kg/m2; 18±10, and 21±8Nm; E-NW vs E-W). Reduced lean mass and torque in the LL in the non walking (2.58±0.04 vs 3.20±0.04 kg/m2 41±19 vs 64±20Nm; E-NW vs E-W p<0,05). Our data demonstrate that age-related sarcopenia results in overall lower muscle mass while contractile function seems to be more affected by daily utilization.
sarcopenia, skeletal muscle, old women, muscle function decline
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11562/463339
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