Release of growth factors and the effect of age, sex, and severity of injury after long bone fracture. A preliminary report.
OBJECTIVE
The systemic response after fracture is regulated by a complex mechanism involving numerous growth factors. In this study, we analyzed the kinetics of key growth factors following lower-limb long bone fracture.


METHODS
Human serum was isolated from 15 patients suffering from lower-limb long bone fracture (tibia/femur) requiring surgical fixation. The levels of platelet-derived growth factor (PDGF-BB), vascular edothelial growth factor (VEGF), insulin growth factor-I (IGF-I), and transforming growth factor β1 (TGF-β1) were assayed by colorimetric ELISA at different time points during the first week after fracture. 10 healthy volunteers made up the control group of the study. Serum levels of the growth factors measured were compared to age, sex, and injury severity score.


RESULTS
We found that there was a decline in the levels of PDGF-BB, IGF-I and TGF-β1 during the first 3 days after fracture. However, VEGF levels remained unchanged. The levels of all the growth factors studied then increased, with the highest concentrations noted at day 7 after surgery. No correlation was found between circulating levels of growth factors and age, injury severity score (ISS), blood loss, or fluid administration.


CONCLUSIONS
There are systemic mitogenic and osteogenic signals after fracture. Important growth factors are released into the peripheral circulation, but early after surgery it appears that serum levels of key growth factors fall. By 7 days postoperatively, the levels had increased considerably. Our findings should be considered in cases where autologous serum is used for ex vivo expansion of mesenchymal stem cells. There should be further evaluation of the use of these molecules as biomarkers of bone union.
Academic Department of Trauma and Orthopaedics, University of Leeds, Leeds, UK. pountos@doctors.org.uk
Ippokratis
I
Pountos
Theodora
T
Georgouli
Karen
K
Henshaw
Howard
H
Bird
Peter V
PV
Giannoudis
D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005264:Femoral Fractures / Q000097:blood / Q000503:physiopathology; D017102:Fracture Healing / Q000502:physiology; D050723:Fractures, Bone / Q000097:blood / Q000503:physiopathology*; D006801:Humans; D015601:Injury Severity Score; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010982:Platelet-Derived Growth Factor / Q000032:analysis / Q000502:physiology*; D012737:Sex Factors; D013978:Tibial Fractures / Q000097:blood / Q000503:physiopathology; D013997:Time Factors; D053773:Transforming Growth Factor beta1 / Q000097:blood / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000097:blood / Q000502:physiology*; D055815:Young Adult
D010982:Platelet-Derived Growth Factor; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; D007334:Insulin-Like Growth Factor I