TY - JOUR

T1 - Type I collagen synthesis and degradation in peritendinous tissue after exercise determined by microdialysis in humans

AU - Langberg, Henning

AU - Skovgaard, D

AU - Petersen, L J

AU - Bulow, J

AU - Kjaer, M

PY - 1999

Y1 - 1999

N2 - 1. Physical activity is known to increase type I collagen synthesis measured as the concentration of biomarkers in plasma. By the use of microdialysis catheters with a very high molecular mass cut-off value (3000 kDa) we aimed to determine local type I collagen synthesis and degradation in the peritendinous region by measuring interstitial concentrations of a collagen propeptide (PICP; 100 kDa) and a collagen degradation product (ICTP; 9 kDa) as well as an inflammatory mediator (PGE2). 2. Seven trained human runners were studied before and after (2 and 72 h) 3 h of running (36 km). Two microdialysis catheters were placed in the peritendinous space ventral to the Achilles' tendon under ultrasound guidance and perfused with a Ringer-acetate solution containing 3H-labelled human type IV collagen and [15-3H(N)]PGE2 for in vivo recovery determination. Relative recovery was 37-59 % (range of the s.e.m. values) for both radioactively labelled substances. 3. PICP concentration decreased in both interstitial peritendinous tissue and arterial blood immediately after exercise, but rose 3-fold from basal 72 h after exercise in the peritendinous tissue (55 +/- 10 microg l-1, mean +/- s.e.m. (rest) to 165 +/- 40 microg l-1 (72 h), P <0.05) and by 25 % in circulating blood (160 +/- 10 microg l-1 (rest) to 200 +/- 12 microg l-1 (72 h), P <0.05). ICTP concentration did not change in blood, but decreased transiently in tendon-related tissue during early recovery after exercise only. PGE2 concentration increased in blood during running, and returned to baseline in the recovery period, whereas interstitial PGE2 concentration was elevated in the early recovery phase. 4. The findings of the present study indicate that acute exercise induces increased formation of type I collagen in peritendinous tissue as determined with microdialysis and using dialysate fibre with a very high molecular mass cut-off. This suggests an adaptation to acute physical loading also in non-bone-related collagen in humans.

AB - 1. Physical activity is known to increase type I collagen synthesis measured as the concentration of biomarkers in plasma. By the use of microdialysis catheters with a very high molecular mass cut-off value (3000 kDa) we aimed to determine local type I collagen synthesis and degradation in the peritendinous region by measuring interstitial concentrations of a collagen propeptide (PICP; 100 kDa) and a collagen degradation product (ICTP; 9 kDa) as well as an inflammatory mediator (PGE2). 2. Seven trained human runners were studied before and after (2 and 72 h) 3 h of running (36 km). Two microdialysis catheters were placed in the peritendinous space ventral to the Achilles' tendon under ultrasound guidance and perfused with a Ringer-acetate solution containing 3H-labelled human type IV collagen and [15-3H(N)]PGE2 for in vivo recovery determination. Relative recovery was 37-59 % (range of the s.e.m. values) for both radioactively labelled substances. 3. PICP concentration decreased in both interstitial peritendinous tissue and arterial blood immediately after exercise, but rose 3-fold from basal 72 h after exercise in the peritendinous tissue (55 +/- 10 microg l-1, mean +/- s.e.m. (rest) to 165 +/- 40 microg l-1 (72 h), P <0.05) and by 25 % in circulating blood (160 +/- 10 microg l-1 (rest) to 200 +/- 12 microg l-1 (72 h), P <0.05). ICTP concentration did not change in blood, but decreased transiently in tendon-related tissue during early recovery after exercise only. PGE2 concentration increased in blood during running, and returned to baseline in the recovery period, whereas interstitial PGE2 concentration was elevated in the early recovery phase. 4. The findings of the present study indicate that acute exercise induces increased formation of type I collagen in peritendinous tissue as determined with microdialysis and using dialysate fibre with a very high molecular mass cut-off. This suggests an adaptation to acute physical loading also in non-bone-related collagen in humans.

KW - Achilles Tendon

KW - Adaptation, Physiological

KW - Adult

KW - Collagen

KW - Collagen Type I

KW - Connective Tissue

KW - Dinoprostone

KW - Exercise

KW - Female

KW - Humans

KW - Male

KW - Peptide Fragments

KW - Peptides

KW - Procollagen

KW - Running

M3 - Journal article

C2 - 10562353

VL - 521 Pt 1

SP - 299

EP - 306

JO - The Journal of Physiology

JF - The Journal of Physiology

SN - 0022-3751

ER -