Serum concentrations of insulin-like growth factor-1, members of the TGF-beta superfamily and follistatin do not reflect different stages of dynapenia and sarcopenia in elderly women.

There is a high need for blood-based biomarkers detecting age-related changes in muscular performance at an early stage. Therefore, we investigated whether serum levels of growth and differentiation factor-15 (GDF-15), activin A, myostatin, follistatin, and insulin-like growth factor-1 (IGF-1) would reflect age- and physical performance-related differences between young (22-28 years) and elderly (65-92 years) females. Isokinetic peak torque of knee extension (PTE) was measured in young females to obtain reference values for the discrimination of different stages of age-associated muscle weakness. Additionally, elderly women were screened for sarcopenia using the algorithm of the European Working Group on Sarcopenia in Older People (low muscle mass in addition to low PTE and/or low walking speed). IGF-1 levels were higher and GDF-15 levels were lower in young females in comparison to the elderly (p < 0.01), whereas members of the activin A/myostatin/follistatin axis showed similar levels across age groups. In older women, IGF-1 correlated negatively with age (ρ = -0.359, p < 0.01) and positively with muscle mass (ρ = 0.365, p < 0.01). In contrast, GDF-15 correlated positively with age (ρ = 0.388, p < 0.001) and negatively with muscle mass (ρ = -0.320, p < 0.01). However, none of the serum markers differed between women classified as non-, mildly and severely dynapenic/sarcopenic. Multiple linear regression analyses revealed that a combination of all blood-based biomarkers obtained in addition to age and fat mass moderately predicted muscle mass (+2.9%). Neither a single nor a combined set of tested biomarkers reflected the presence of dynapenia or sarcopenia in elderly women. However, due to the associations of IGF-1 and GDF-15 with correlates of muscle mass and function, these parameters remain promising candidates in a potential set of blood-based biomarkers to diagnose sarcopenia and/or dynapenia.