Influence of age and physical fitness on miRNA-21, TGF-β and its receptors in leukocytes of healthy women

The TGF-β superfamily has been shown to play an important role in a wide range of physiological as well as pathological processes including ageing, immune modulation, atherosclerosis and cancer development. The aim of the current study was to investigate (i) whether TGF-β signalling in peripheral blood mononuclear cells (PBMCs) would differ between young and old females and (ii) whether physical performance parameters of elderly women would be related to the expression of TGF-β or its receptors. Sixteen healthy young (22-28 years; YF) and 90 healthy older (65-92 years; OF) females participated in the study. In addition to several components of health-related physical fitness, circulating CRP and TGF-β levels were determined together with the mRNA expression of TGF-β, TGF-βRI, TGF-βRII, and miRNA-21 (known to interfere with TGF-β signalling) in PBMCs. Physical fitness as determined by 6-minutes walking test (YF:median 932 (range 573-1254) m; OF:360 (114-558) m), handgrip strength (YF: 32 (24-39) kg; OF:18(10-30) kg), relative isokinetic peak torque of knee extensors (YF:1.9 (1.2- 2.3) Nm/kg; OF:1.0 (0.2-1.9) Nm/kg and flexors (YF: 1.1 (0.7- 1.5) Nm/kg; OF: 0.5 (0.2-1.0) Nm/kg was substantially lower in older women (p