Details

Autor(en) / Beteiligte

• Hiepe, Patrick
• Gussew, Alexander
• Rzanny, Reinhard
• Kurz, Eduard
• Anders, Christoph
• Walther, Mario
• Scholle, Hans-Christoph
• Reichenbach, Jürgen R.

Titel

Age-related structural and functional changes of low back muscles

Ist Teil von

• Experimental gerontology, 2015-05, Vol.65, p.23-34

Ort / Verlag

England: Elsevier Inc

Erscheinungsjahr

2015

Quelle

MEDLINE

Beschreibungen/Notizen

• During aging declining maximum force capacity with more or less unchanged fatigability is observed with the underlying mechanisms still not fully understood. Therefore, we compared morphology and function of skeletal muscles between different age groups. Changes in high-energy phosphate turnover (PCr, Pi and pH) and muscle functional MRI (mfMRI) parameters, including proton transverse relaxation time (T2), diffusion (D) and vascular volume fraction (f), were investigated in moderately exercised low back muscles of young and late-middle-aged healthy subjects with 31P-MR spectroscopy, T2- and diffusion-weighted MRI at 3T. In addition, T1-weighted MRI data were acquired to determine muscle cross-sectional areas (CSA) and to assess fat infiltration into muscle tissue. Except for pH, both age groups showed similar load-induced MR changes and rates of perceived exertion (RPE), which indicates comparable behavior of muscle activation at moderate loads. Changes of mfMRI parameters were significantly associated with RPE in both cohorts. Age-related differences were observed, with lower pH and higher Pi/ATP ratios as well as lower D and f values in the late-middle-aged subjects. These findings are ascribed to age-related changes of fiber type composition, fiber size and vascularity. Interestingly, post exercise f was negatively associated with fat infiltration with the latter being significantly higher in late-middle-aged subjects. CSA of low back muscles remained unchanged, while CSA of inner back muscle as well as mean T2 at rest were associated with maximum force capacity. Overall, applying the proposed MR approach provides evidence of age-related changes in several muscle tissue characteristics and gives new insights into the physiological processes that take place during aging. This work analyzes load-induced metabolic, vascular and T2 changes in low back muscles of healthy, young and late-middle-aged subjects by combining 31P-CSI, T2- and diffusion-weighted MRI. In addition anatomic MRI was applied to determine age-related changes in muscle cross-sectional area and fat infiltration. Finally, derived parameters were compared to each other and showed some interesting associations that may provide new insights into muscle physiology during healthy aging. [Display omitted] •MR investigation of morphology, metabolism and vascularity in back muscles•Young and late-middle-aged subjects showed similar muscle endurance.•Metabolic and vascular volume fraction changes were associated with T2.•pH, Pi, diffusibility and vascular volume fraction were reduced with age.•Vascular volume fraction was negatively associated with fat infiltration.