Expression of IGF-I splice variants in young and old human skeletal muscle after high resistance exercise

Hameed, M; Orrell, Richard W.; Cobbold, M; Goldspink, Geoffrey; Harridge, Sdr

doi:10.1111/j.1469-7793.2003.00247.x

Cited by 182 publications

(180 citation statements)

References 34 publications

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“…The higher IGF-I mRNA level after CET suggests that IGF-I expression is not only controlled by acute load-induced damage (Bamman et al 2001), but also linked to the augmentation of mechanical and metabolic activities in untrained individuals. The finding of a tendency for an increase of fiber cross-sectional area and IGF-I mRNA expression after the exercise training protocol with shortening contractions supports the implication of this growth factor in the muscular remodeling response following an endurance training in untrained subjects (McKoy et al 1999;Hameed et al 2003). This increase of IGF-I expression could be one of the principal transcriptional events with endurance exercise.…”

Section: Contractile Alterationssupporting

confidence: 63%

Gene expression in skeletal muscle of coronary artery disease patients after concentric and eccentric endurance training

Zoll

Steiner²,

Meyer³

et al. 2005

Eur J Appl Physiol

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Low-intensity concentric (CET) and eccentric (EET) endurance-type training induce specific structural adaptations in skeletal muscle. We evaluated to which extent steady-state adaptations in transcript levels are involved in the compensatory alterations of muscle mitochondria and myofibrils with CET versus EET at a matched metabolic exercise intensity of medicated, stable coronary patients (CAD). Biopsies were obtained from vastus lateralis muscle before and after 8 weeks of CET (n=6) or EET (n=6). Transcript levels for factors involved in mitochondrial biogenesis (PGC-1alpha, Tfam), mitochondrial function (COX-1, COX-4), control of contractile phenotype (MyHC I, IIa, IIx) as well as mechanical stress marker (IGF-I) were quantified using an reverse-transcriptase polymerase chain reaction approach. After 8 weeks of EET, a reduction of the COX-4 mRNA level by 41% and a tendency for a drop in Tfam transcript concentration (-33%, P=0.06) was noted. This down-regulation corresponded to a drop in total mitochondrial volume density. MyHC-IIa transcript levels were specifically decreased after EET, and MyHC-I mRNA showed a trend towards a reduction (P=0.08). Total fiber cross-sectional area was not altered. After CET and EET, the IGF-I mRNA level was significantly increased. The PGC-1alpha significantly correlated with Tfam, and both PGC-1alpha and Tfam significantly correlated with COX-1 and COX-4 mRNAs. Post-hoc analysis identified significant interactions between the concurrent medication and muscular transcript levels as well as fiber size. Our findings support the concept that specific transcriptional adaptations mediate the divergent mitochondrial response of muscle cells to endurance training under different load condition and indicate a mismatch of processes related to muscle hypertrophy in medicated CAD patients.

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Section: Contractile Alterationssupporting

confidence: 63%

Gene expression in skeletal muscle of coronary artery disease patients after concentric and eccentric endurance training

Zoll

Steiner²,

Meyer³

et al. 2005

Eur J Appl Physiol

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“…Previous studies mainly focused on IGF-1, however, the regulation of IGF-1 mRNA and of its splice variants in response to strength training remains unclear. Studies on acute changes in human skeletal muscle provided equivocal results showing either signiWcant increases in mRNAs of IGF-1 and its splice variant MGF (mechano-growth factor) (Bamman et al 2001;Hameed et al 2003;Kim et al 2005a, b;Petrella et al 2006), unchanged IGF-1 or downregulated IGF-1 gene expression (Psilander et al 2003). To our knowledge, IGF steady-state mRNA levels were only shown to be increased after several weeks of classic strength training Petrella et al 2006;Kvorning et al 2007).…”

Section: Hypertrophymentioning

confidence: 72%

“…IGFs, which are secreted by liver and skeletal muscle, play a prominent role in mediating muscle hypertrophy in response to strength training. SigniWcant acute increases in the mRNAs of IGF-1 have been reported in human muscle after concentric/eccentric strength training (Hameed et al 2003;Kim et al 2005a, b;Petrella et al 2006) and IGF-1 mRNAs were also found to be signiWcantly increased after several weeks of heavy quadriceps strength training Kvorning et al 2007;Petrella et al 2006).…”

Section: Introductionmentioning

confidence: 90%

Effects of strength training with eccentric overload on muscle adaptation in male athletes

et al. 2009

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In classic concentric/eccentric exercise, the same absolute load is applied in concentric and eccentric actions, which infers a smaller relative eccentric load. We compared the effects of 6 weeks of classic concentric/eccentric quadriceps strength training (CON/ECC, 11 subjects) to eccentric overload training (CON/ECC+, 14 subjects) in athletes accustomed to regular strength training. The parameters determined included functional tests, quadriceps and fibre cross-sectional area (CSA), fibre type distribution by ATPase staining, localisation of myosin heavy chain (MHC) isoform mRNAs by situ hybridization and the steady-state levels of 48 marker mRNAs (RT-PCR) in vastus lateralis biopsies taken before and after training. Both training forms had anabolic effects with significant increases in quadriceps CSA, maximal strength, ribosomal RNA content and the levels of mRNAs involved in growth and regeneration. Only the CON/ECC+ training led to significantly increased height in a squat jump test. This was accompanied by significant increases in IIX fibre CSA, in the percentage of type IIA fibres expressing MHC IIx mRNA, in the level of mRNAs preferentially expressed in fast, glycolytic fibres, and in post-exercise capillary lactate. The enhanced eccentric load apparently led to a subtly faster gene expression pattern and induced a shift towards a faster muscle phenotype plus associated adaptations that make a muscle better suited for fast, explosive movements.

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“…It is generally believed that in ageing protein synthesis is decreased (Balagopal et al 1997). Moreover, the response of the muscular IGF1 isoform to resistance exercise is lower (Hameed et al 2003). However, signiWcant hypertrophy at muscle level can occur in elderly subjects (Frontera et al 1988;Narici et al 2004).…”

Section: Size and Force Of Muscle Wbresmentioning

confidence: 96%

Long-term resistance training improves force and unloaded shortening velocity of single muscle fibres of elderly women

et al. 2008

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Four elderly women (78 +/- 4.3 years) were resistance trained (RT) for one year and needle biopsies of the vastus lateralis muscle were taken pre- and post-RT. A training intensity of 60% one-repetition maximum (1RM) was adopted for the entire duration of the study. Following RT, significant gain in isometric force of the quadriceps muscles was observed and MHC isoform distribution of vastus lateralis muscle showed a very significant shift from MHC-1 and MHC-2X towards MHC-2A, i.e. a bi-directional shift. A large population (n = 310) of individual skinned muscle fibres were dissected from biopsy samples and used for determination of cross-sectional area (CSA), specific force (Po/CSA) and unloaded shortening velocity (Vo) at 12 degrees C and maximum activation. Fibres were classified on the basis of their MHC isoform content determined by SDS-PAGE in three pure fibre types (1, 2A and 2X) and two hybrid fibre types (1-2A and 2AX). Whereas the CSA of individual muscle fibres did not change, Po/CSA was significantly higher in both type 1 and type 2A fibres post training. Vo of type 1 fibres was significantly higher post-training, whereas no change in Vo was observed in type 2A fibres. The number of pure type 2X fibres was very low especially post-training and did not enable a statistically significant comparison. The data suggest that in elderly women moderate and prolonged RT: (1) can determine similar adaptations in MHC distribution of skeletal muscle to those expected in young subjects; (2) can improve function of muscle fibres.

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Expression of IGF-I splice variants in young and old human skeletal muscle after high resistance exercise

Cited by 182 publications

References 34 publications

Gene expression in skeletal muscle of coronary artery disease patients after concentric and eccentric endurance training

Gene expression in skeletal muscle of coronary artery disease patients after concentric and eccentric endurance training

Effects of strength training with eccentric overload on muscle adaptation in male athletes

Long-term resistance training improves force and unloaded shortening velocity of single muscle fibres of elderly women

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