Tendon and skeletal
muscle matrix gene expression and functional responses to immobilisation and
rehabilitation in young males: Effect of growth hormone administration
muscle matrix gene expression and functional responses to immobilisation and
rehabilitation in young males: Effect of growth hormone administration
Boeson
AP, Dideriksen K, Couppe C, Magnusson P, Schjerling P, Boeson M, Kjaer M, Langberg
H. J Physiol. 2013; 591(20).
AP, Dideriksen K, Couppe C, Magnusson P, Schjerling P, Boeson M, Kjaer M, Langberg
H. J Physiol. 2013; 591(20).
Take Home Message: Human
growth hormone stimulates collagen expression in skeletal muscle and tendon and
abolishes the normal decline seen during inactivity and rehabilitation.
growth hormone stimulates collagen expression in skeletal muscle and tendon and
abolishes the normal decline seen during inactivity and rehabilitation.
Counteracting
the loss of muscle and tendon during periods of immobilization and
rehabilitation is a challenge for medical personnel. The interaction of the
human growth hormone
(GH) and insulin growth factor 1(IGF-1; a protein involved in tissue
growth) helps regulate collagen tissue turnover within musculotendinous
junctions. Therefore, the authors investigated the effect of GH supplementation
on musculotendinous tissue during inactivity and rehabilitation. The authors
randomly selected one lower extremity to cast (from hip to ankle) for two weeks
among 20 healthy, physically untrained men (~23 years of age). The men then
completed a supervised unilateral rehabilitation program: 3 times a week for 6
weeks (18 sessions total). Participants performed unilateral (immobilized limb
only) knee extension and leg press. They increased sets and weight on a weekly
basis using a 5-repetition maximum test. Participants were randomly assigned to
receive subcutaneous injections of GH supplementation (10 participants; 33.3
ugkg-1day-1 to 50 ugkg-1day-1) or a
placebo (10 participants) for 8 weeks. Participants performed injections before
bedtime and the authors collected blood samples early the next morning to
measure hormone levels. The authors evaluated the immobilized limb at baseline
and then every two weeks for several outcomes: 1) Structural measurements (i.e.,
MRI of
medial quadriceps and patellar tendon cross-sectional area), 2) maximum
voluntary quadriceps contraction, 3) and patella tendon mechanical properties
(using strain gauge and ultrasound; tendon force/cross sectional area). The authors also
collected muscle biopsies from both limbs at baseline as well as 2 and 6 weeks
after rehabilitation. They used the muscle biopsies to measure the amount of
gene expression and collagen
fibrils. After the immobilization period both groups had decreased strength and
cross-sectional area, which was equally regained during their. Tendon fibril
diameter remained unchanged. There
was an initial decline in tendon stiffness (elasticity) after 2 weeks of
immobilization observed in the placebo group; however, it returned to baseline
level following rehabilitation. The GH supplementation group never encountered
a decline in tendon stiffness during immobilization, and following 6 weeks of
rehabilitation there was an increase in tendon stiffness. During
rehabilitation both groups had greater IGF-1 and collagen expression compared with
baseline; however, the rise was more pronounced in those that received the GH
injections. Additionally, IGF-1 gene expression increased during the
immobilization period only in the GH group.
the loss of muscle and tendon during periods of immobilization and
rehabilitation is a challenge for medical personnel. The interaction of the
human growth hormone
(GH) and insulin growth factor 1(IGF-1; a protein involved in tissue
growth) helps regulate collagen tissue turnover within musculotendinous
junctions. Therefore, the authors investigated the effect of GH supplementation
on musculotendinous tissue during inactivity and rehabilitation. The authors
randomly selected one lower extremity to cast (from hip to ankle) for two weeks
among 20 healthy, physically untrained men (~23 years of age). The men then
completed a supervised unilateral rehabilitation program: 3 times a week for 6
weeks (18 sessions total). Participants performed unilateral (immobilized limb
only) knee extension and leg press. They increased sets and weight on a weekly
basis using a 5-repetition maximum test. Participants were randomly assigned to
receive subcutaneous injections of GH supplementation (10 participants; 33.3
ugkg-1day-1 to 50 ugkg-1day-1) or a
placebo (10 participants) for 8 weeks. Participants performed injections before
bedtime and the authors collected blood samples early the next morning to
measure hormone levels. The authors evaluated the immobilized limb at baseline
and then every two weeks for several outcomes: 1) Structural measurements (i.e.,
MRI of
medial quadriceps and patellar tendon cross-sectional area), 2) maximum
voluntary quadriceps contraction, 3) and patella tendon mechanical properties
(using strain gauge and ultrasound; tendon force/cross sectional area). The authors also
collected muscle biopsies from both limbs at baseline as well as 2 and 6 weeks
after rehabilitation. They used the muscle biopsies to measure the amount of
gene expression and collagen
fibrils. After the immobilization period both groups had decreased strength and
cross-sectional area, which was equally regained during their. Tendon fibril
diameter remained unchanged. There
was an initial decline in tendon stiffness (elasticity) after 2 weeks of
immobilization observed in the placebo group; however, it returned to baseline
level following rehabilitation. The GH supplementation group never encountered
a decline in tendon stiffness during immobilization, and following 6 weeks of
rehabilitation there was an increase in tendon stiffness. During
rehabilitation both groups had greater IGF-1 and collagen expression compared with
baseline; however, the rise was more pronounced in those that received the GH
injections. Additionally, IGF-1 gene expression increased during the
immobilization period only in the GH group.
The
researchers demonstrated that GH supplementation helps maintain levels of IGF-1
gene expression during inactivity and rehabilitation, which may abolish the
normal decline in tendon stiffness. It was interesting to note that there was
no change in muscle size, strength, or number of fibers, which suggests that
low levels of GH injections induce a collagen stabilizing effect during periods
of inactivity without effecting skeletal muscle contractile proteins. However,
baseline GH levels were not recorded so the gain could have been due to people
in that group having lower resting levels of GH and therefore they may have
benefited more from the supplement. This research suggests that young healthy
individuals may benefit from GH supplementation during periods of
immobilization and rehabilitation. Maintaining and increasing tendon stiffness
could accelerate full functional return to play quicker without the risk of
re-injury.
researchers demonstrated that GH supplementation helps maintain levels of IGF-1
gene expression during inactivity and rehabilitation, which may abolish the
normal decline in tendon stiffness. It was interesting to note that there was
no change in muscle size, strength, or number of fibers, which suggests that
low levels of GH injections induce a collagen stabilizing effect during periods
of inactivity without effecting skeletal muscle contractile proteins. However,
baseline GH levels were not recorded so the gain could have been due to people
in that group having lower resting levels of GH and therefore they may have
benefited more from the supplement. This research suggests that young healthy
individuals may benefit from GH supplementation during periods of
immobilization and rehabilitation. Maintaining and increasing tendon stiffness
could accelerate full functional return to play quicker without the risk of
re-injury.
Questions for Discussion:
Would you give your athlete small doses of GH during periods of immobilization
and rehabilitation? Do you believe this would be safe in a different population
(e.g., females, adolescent)?
Would you give your athlete small doses of GH during periods of immobilization
and rehabilitation? Do you believe this would be safe in a different population
(e.g., females, adolescent)?
Written by: Jane McDevitt PhD
Reviewed
by: Stephen Thomas & Jeff Driban
by: Stephen Thomas & Jeff Driban
Related Posts:
Boesen AP, Dideriksen K, Couppé C, Magnusson P, Schjerling P, Boesen M, Kjaer M, & Langberg H (2013). Tendon and skeletal muscle matrix gene expression and functional responses to immobilisation and rehabilitation in young males: Effect of growth hormone administration. The Journal of Physiology PMID: 24081158
I find this idea extremely interesting. I have often thought about the positive effects of short-term and controlled use of these anabolic substances. I feel that these substances can be very beneficial if used properly, however, the stigma surrounding these substances involves the poor, long-term effects due to abuse.
I do not follow this line of research closely, but I think should more studies show the positive short-term effects of using these substances in a controlled, closely monitored manner, I would strongly consider the use of this treatment on my athletes. I think this could be applicable to a variety of populations because GH seems to be found in some amount in almost everyone.
This is a great idea and could potentially cause a paradigm shift in the management of musculoskeletal injury if society's perception of GH can be changed and studies continue to show it's benefits.
Jake,
I agree GH supplementation looks very promising. I thought it was especially interesting they were able to find volunteers for this study, but it was great to see the affects within human participants. I think you make a great point on following them prospectivly to see the short term effects. I would also like to see baseline GH levels and then follow-up to determine if the levels reamain normal some time after the rehabilitation is completed.
HGH is responsible for fat loss, building muscle mass, increased energy levels, a sharper memory, a boosted immune system, and more.
Since the natural production of HGH slows down with age, many men will reach for those supplements that claim the ability to help enhance HGH production. Not all of these releasers are all that reliable. Some are good and some are not so good.
I find this research to be extremely intriguing. The bad name that steroids have in athletics these days overshadows the controlled and medicinal benefits of these drugs. However, with research such as this, these stigmas can be overturned and progress can be made health wise. I agree that the fact that people volunteered for this study was surprising to me, but to see the effects on humans is excellent. I think overall, this is a great idea, and I am interested to see where this research takes us.