Muscle tissue inevitably declines with age, but much can be done to minimize and even reverse a loss of strength Try using free weights or resistance machines.
The cytokine interleukin-15 (IL-15) is highly expressed in skeletal muscle tissue and declines in aging rodent models.
During aging, adipose tissue volume increases, skeletal muscle tissue volume declines, and the remaining muscle tissue is susceptible to lipid infiltration [ 19].
Human body mass, of which skeletal muscle is the most abundant tissue, declines with age [ 1].
Although diminished satellite cell numbers have been implicated in the age-related decline of muscle tissue regeneration, several reports identified key molecular changes within Notch and P-Smad3 signaling in the aged endogenous populations (Conboy et al., 2003; Carlson & Conboy, 2007b; Carlson et al., 2008).
If so, it remains to be explored which factor(s) that up-regulates mTOR expression in muscle tissue when endocrine IGF-I is declined, particularly during starvation of knockout mice.
Such data indicate muscle tissue composition changes and, consequently, its functional decline.
Muscle tissue produces myostatin, so the age-specific decline in myostatin protein may reflect the loss of muscle mass in the old.
This can result in replacement of the muscle tissue with fat and connective tissue, age-related decline of muscle fibers, reduced muscle performance or progressive deficits in metabolic capacity (Rissanen et al., 2002).
Adult skeletal muscle tissue has a uniquely robust capacity for regeneration, which gradually declines with aging or is compromised in muscle diseases.
