The role of circulating bone cell precursors in fracture healing.
Fracture healing is a complex process that involves several cell types; as a previous report suggested an increase in osteoblast (OB) precursors in peripheral blood during this process, this paper examines the role of circulating bone cell precursors in this process in the light of a prior suggestion that OB precursors are increased. Nine healthy men less than 60 years old with traumatic fractures were enrolled. The parameters circulating OB precursors (osteocalcin+/alkaline phosphatase+/CD15- cells) and osteoclast precursors (CD14+/CD11b+/vitronectin receptor + cells) were measured by flow cytometry; bone formation markers and TGFbeta1, by ELISA; and PTH, by RIA in serum on arrival at the emergency department (baseline) and 15 days after fracture. Bone cell precursors behaved differently during healing. TGFbeta1 was inversely correlated with OB number, but increased their degree of maturation at baseline. Bone formation markers and TGFbeta1 were increased after fracture, whereas PTH was decreased. The TGFbeta1 increase was directly correlated with age, whereas age was not correlated with the precursors. In conclusion, we confirm the role of TGFbeta1 in fracture healing; and its possible role in the control of pre-OB homeostasis. There was no variation in circulating precursor cells during healing, though the increase in TGFbeta1 may suggest increased pre-OB maturation and homing to the injured site.
D'Amelio
Patrizia
P
Section of Gerontology, Department of Surgical and Medical Disciplines, University of Torino, Corso Bramante 88/90, Turin, Italy. patrizia.damelio@unito.it
Cristofaro
Maria Angela
MA
Grimaldi
Anastasia
A
Ravazzoli
Marco
M
Pluviano
Fernanda
F
Grosso
Elena
E
Pescarmona
Gian Piero
GP
Isaia
Giovanni Carlo
GC
D000293:Adolescent; D000328:Adult; D002469:Cell Separation; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D017102:Fracture Healing / Q000502:physiology*; D050723:Fractures, Bone; D006801:Humans; D008297:Male; D008875:Middle Aged; D010006:Osteoblasts / Q000166:cytology*; D010010:Osteoclasts / Q000166:cytology*; D010281:Parathyroid Hormone / Q000097:blood; D011863:Radioimmunoassay; D013234:Stem Cells / Q000166:cytology*; D053773:Transforming Growth Factor beta1 / Q000097:blood; D055815:Young Adult
D010281:Parathyroid Hormone; D053773:Transforming Growth Factor beta1