Exercise-dependent IGF-I, IGFBPs, and type I collagen changes in human peritendinous connective tissue determined by microdialysis
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Exercise-dependent IGF-I, IGFBPs, and type I collagen changes in human peritendinous connective tissue determined by microdialysis. / Olesen, Jens L; Heinemeier, Katja M; Gemmer, Carsten; Kjaer, Michael; Flyvbjerg, Allan; Langberg, Henning.
In: Journal of Applied Physiology, Vol. 102, No. 1, 2007, p. 214-20.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Exercise-dependent IGF-I, IGFBPs, and type I collagen changes in human peritendinous connective tissue determined by microdialysis
AU - Olesen, Jens L
AU - Heinemeier, Katja M
AU - Gemmer, Carsten
AU - Kjaer, Michael
AU - Flyvbjerg, Allan
AU - Langberg, Henning
PY - 2007
Y1 - 2007
N2 - Microdialysis studies indicate that mechanical loading of human tendon during exercise elevates type I collagen production in tendon. However, the possibility that the insertion of microdialysis fibers per se may increase the local collagen production due to trauma has not been explored. Insulin-like growth factor I (IGF-I) and its binding proteins (IGFBPs), which are known to stimulate collagen production in animal tendons, may regulate the translation of mechanical loading to collagen synthesis. Systemic and tissue levels of IGF-I, IGFBP, and type I collagen metabolism markers [procollagen I COOH-terminal propeptide (PICP) and COOH-terminal telopeptide of type I collagen] were measured by microdialysis in peritendinous tissue of the human Achilles tendon in an exercise group (performing a 36-km run, n = 6) and a control group (no intervention, n = 6). An increase in local PICP concentration was seen in both groups after 72 h and stayed elevated in the exercise group at 96 h (P <0.05). IGFBP-1 in both serum and dialysate increased in the exercise group immediately after exercise (P <0.05), whereas IGFBP-3 decreased systemically (P <0.05). Elevation of local IGFBP-4 was observed in both the control and exercise groups after 48 h (P <0.05). Total IGF-I did not change in locally or systemically in either group. Our results indicate an increased local production of PICP in human peritendinous tissue in response to prolonged mechanical loading with part of the increase due to trauma from the sampling technique. Care must therefore be emphasized to minimize the numbers of insertions with microdialysis. We demonstrated an elevation of IGFBP-1 both systemically and peritendinously in response to prolonged acute exercise. The local increased collagen synthesis was preceded by an elevation of local concentration of IGFBP-4, suggesting that IGFBP-4 may have a key role in the IGF-axis effect on the human collagen synthesis in vivo.
AB - Microdialysis studies indicate that mechanical loading of human tendon during exercise elevates type I collagen production in tendon. However, the possibility that the insertion of microdialysis fibers per se may increase the local collagen production due to trauma has not been explored. Insulin-like growth factor I (IGF-I) and its binding proteins (IGFBPs), which are known to stimulate collagen production in animal tendons, may regulate the translation of mechanical loading to collagen synthesis. Systemic and tissue levels of IGF-I, IGFBP, and type I collagen metabolism markers [procollagen I COOH-terminal propeptide (PICP) and COOH-terminal telopeptide of type I collagen] were measured by microdialysis in peritendinous tissue of the human Achilles tendon in an exercise group (performing a 36-km run, n = 6) and a control group (no intervention, n = 6). An increase in local PICP concentration was seen in both groups after 72 h and stayed elevated in the exercise group at 96 h (P <0.05). IGFBP-1 in both serum and dialysate increased in the exercise group immediately after exercise (P <0.05), whereas IGFBP-3 decreased systemically (P <0.05). Elevation of local IGFBP-4 was observed in both the control and exercise groups after 48 h (P <0.05). Total IGF-I did not change in locally or systemically in either group. Our results indicate an increased local production of PICP in human peritendinous tissue in response to prolonged mechanical loading with part of the increase due to trauma from the sampling technique. Care must therefore be emphasized to minimize the numbers of insertions with microdialysis. We demonstrated an elevation of IGFBP-1 both systemically and peritendinously in response to prolonged acute exercise. The local increased collagen synthesis was preceded by an elevation of local concentration of IGFBP-4, suggesting that IGFBP-4 may have a key role in the IGF-axis effect on the human collagen synthesis in vivo.
KW - Adult
KW - Biomechanics
KW - Collagen Type I
KW - Connective Tissue
KW - Exercise
KW - Gene Expression Regulation
KW - Humans
KW - Insulin-Like Growth Factor Binding Protein 1
KW - Insulin-Like Growth Factor Binding Protein 4
KW - Insulin-Like Growth Factor Binding Proteins
KW - Insulin-Like Growth Factor I
KW - Male
KW - Microdialysis
KW - Middle Aged
KW - Peptide Fragments
KW - Procollagen
KW - Tendons
KW - Time Factors
U2 - 10.1152/japplphysiol.01205.2005
DO - 10.1152/japplphysiol.01205.2005
M3 - Journal article
C2 - 16973813
VL - 102
SP - 214
EP - 220
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 1
ER -
ID: 38366236