title: Is sonic Hedgehog involved in human fracture healing? --a prospective study on local and systemic concentrations of SHH.
abstract: BACKGROUND
  Sonic Hedgehog (SHH) is a new signalling pathway in bone repair. Evidence exist that SHH pathway plays a significant role in vasculogenesis and limb development during embryogenesis. Some in vitro and animal studies has already proven its potential for bone regeneration. However, no data on the role of SHH in the human fracture healing have been published so far.
  
  
  METHODS
  Seventy-five patients with long bone fractures were included into the study and divided in 2 groups. First group contained 69 patients with normal fracture healing. Four patients with impaired fracture healing formed the second group. 34 volunteers donated blood samples as control. Serum samples were collected over a period of 1 year following a standardized time schedule. In addition, SHH levels were measured in fracture haematoma and serum of 16 patients with bone fractures.
  
  
  RESULTS
  Fracture haematoma and patients serum both contained lower SHH concentrations compared to control serum. The comparison between the patients' serum SHH level and the control serum revealed lower levels for the patients at all measurement time points. Significantly lower concentrations were observed at weeks 1 and 2 after fracture. SHH levels were slightly decreased in patients with impaired fracture healing without statistical significance.
  
  
  CONCLUSIONS
  This is the first study to report local and systemic concentration of SHH in human fracture healing and SHH serum levels in healthy adults. A significant reduction of the SHH levels during the inflammatory phase of fracture healing was found. SHH concentrations in fracture haematoma and serum were lower than the concentration in control serum for the rest of the healing period. Our findings indicate that there is no relevant involvement of SHH in human fracture healing. Fracture repair process seem to reduce the SHH level in human. Further studies are definitely needed to clarify the underlying mechanisms.
authors.affiliation: University Clinic for Traumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Eipeldauer
authors.affiliation: Department of Gender Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Anita
authors.initials: A
authors.lastname: Thomas
authors.affiliation: University Clinic for Traumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Leonard
authors.initials: L
authors.lastname: Hoechtl-Lee
authors.affiliation: University Clinic for Traumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Mathias
authors.initials: M
authors.lastname: Kecht
authors.affiliation: University Clinic for Traumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Binder
authors.affiliation: University Clinic for Traumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Koettstorfer
authors.affiliation: University Clinic for Traumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Gregori
authors.affiliation: University Clinic for Traumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Kambiz
authors.initials: K
authors.lastname: Sarahrudi
mesh_terms: D000328:Adult; D017102:Fracture Healing; D050723:Fractures, Bone / Q000097:blood / Q000378:metabolism / Q000503:physiopathology* / Q000601:surgery; D005786:Gene Expression Regulation; D053823:Hedgehog Proteins / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012086:Reoperation; D017211:Treatment Failure
chemical_list: D053823:Hedgehog Proteins