title: Serum biomarker levels for musculoskeletal disease in two- and three-year-old racing Thoroughbred horses: A prospective study of 130 horses.
abstract: BACKGROUND
  Biomarkers have shown some in vivo promise for the detection of musculoskeletal injuries, but further study to assess biomarker levels in clinical orthopaedic disease is required.
  
  
  OBJECTIVE
  To assess 7 serum biomarkers for the detection of musculoskeletal injuries.
  
  
  METHODS
  Two- and 3-year-old racehorses were entered into the study (n = 238). Exit criteria were lack of training for >30 days, or completion of 10 study months. Data from horses with solitary musculoskeletal injuries and completion of >2 months were analysed. Musculoskeletal injury was considered intra-articular fragmentation (IAF), tendon or ligamentous injury (TL), stress fractures (SF) and dorsal metacarpal disease (DMD). Monthly lameness examination and serum collection were performed. Serum was analysed for glycosaminoglycan (GAG), type I and II collagen degradation (C1, 2C), type II collagen synthesis (CPII), type II collagen degradation (Col CEQ), aggrecan synthesis (CS846), osteocalcin (OC) as a marker of bone formation and (C-terminal telopeptide of type I collagen) CTX as a marker of bone degradation.
  
  
  RESULTS
  Of the 238 horses 59 injured and 71 uninjured control horses met the analysis criteria. Based on injury no significant differences in the proportions were observed for age, gender or lesion type, although a higher proportion of injuries occurred at the beginning of the study. Of injured horses, 16 (27%) sustained an IAF, 17 (29%) a TL injury, 7 (12%) SF and 19 (32%) were diagnosed with DMD. There were significant changes seen in biomarkers based on the injury incurred when longitudinal samples were assessed. Furthermore, based on the serum biomarkers collected prior to injury, horses could be correctly classified as injured or uninjured 73.8% of the time.
  
  
  CONCLUSIONS
  A unique biomarker pattern occurred before each injury and this was beneficial in classifying horses as injured or uninjured.
  
  
  CONCLUSIONS
  Biomarkers have the potential to be used as a screening aid prior to musculoskeletal injury.
authors.affiliation: Gail Holmes Equine Orthopaedic Research Center, Colorado State University, USA. dfrisbie@colostate.edu
authors.forename: D D
authors.initials: DD
authors.lastname: Frisbie
authors.forename: C W
authors.initials: CW
authors.lastname: Mc Ilwraith
authors.forename: R M
authors.initials: RM
authors.lastname: Arthur
authors.forename: J
authors.initials: J
authors.lastname: Blea
authors.forename: V A
authors.initials: VA
authors.lastname: Baker
authors.forename: R C
authors.initials: RC
authors.lastname: Billinghurst
mesh_terms: D000375:Aging; D000818:Animals; D015415:Biomarkers; D006734:Horse Diseases / Q000097:blood* / Q000175:diagnosis; D006736:Horses; D018482:Muscle, Skeletal / Q000293:injuries*; D009135:Muscular Diseases / Q000097:blood / Q000175:diagnosis / Q000662:veterinary*; D010805:Physical Conditioning, Animal; D011446:Prospective Studies; D013177:Sports
chemical_list: D015415:Biomarkers