This concept is particularly relevant in aging muscle where chronic low-level TNF-α exposure and changing IGF-I concentrations are strongly associated with muscle wasting in vivo and the pathologies of sarcopenia and cachexia (Li & Reid, 2000; Meadows et al., 2000; Foulstone et al., 2001; Greiwe et al., 2001; Bruunsgaard et al., 2003a,b; Bruunsgaard & Pedersen, 2003; Stewart et al., 2004; Grohmann et al., 2005; Li et al., 2005; Saini et al., 2006, 2008, 2010, 2012). Here, IGF1 is linked to sarcopenia.