title: Histological and molecular characterisation of feline humeral condylar osteoarthritis.
abstract: BACKGROUND
  Osteoarthritis (OA) is a clinically important and common disease of older cats. The pathological changes and molecular mechanisms which underpin the disease have yet to be described. In this study we evaluated selected histological and transcriptomic measures in the articular cartilage and subchondral bone (SCB) of the humeral condyle of cats with or without OA.
  
  
  RESULTS
  The histomorphometric changes in humeral condyle were concentrated in the medial aspect of the condyle. Cats with OA had a reduction in articular chondrocyte density, an increase in the histopathological score of the articular cartilage and a decrease in the SCB porosity of the medial part of the humeral condyle. An increase in LUM gene expression was observed in OA cartilage from the medial part of the humeral condyle.
  
  
  CONCLUSIONS
  Histopathological changes identified in OA of the feline humeral condyle appear to primarily affect the medial aspect of the joint. Histological changes suggest that SCB is involved in the OA process in cats. Differentiating which changes represent OA rather than the aging process, or the effects of obesity and or bodyweight requires further investigation.
authors.affiliation: Royal (Dick) School of Veterinary Studies and Roslin Institute, Division of Veterinary Clinical Sciences, Hospital for Small Animals, Easter Bush Veterinary Centre, The University of Edinburgh, Roslin, Midlothian EH25 9RG, Scotland.
authors.forename: John M
authors.initials: JM
authors.lastname: Ryan
authors.forename: B Duncan X
authors.initials: BD
authors.lastname: Lascelles
authors.forename: Javier
authors.initials: J
authors.lastname: Benito
authors.forename: Jon
authors.initials: J
authors.lastname: Hash
authors.forename: Sionagh H
authors.initials: SH
authors.lastname: Smith
authors.forename: David
authors.initials: D
authors.lastname: Bennett
authors.forename: David J
authors.initials: DJ
authors.lastname: Argyle
authors.forename: Dylan N
authors.initials: DN
authors.lastname: Clements
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology; D002371:Cat Diseases / Q000378:metabolism / Q000473:pathology*; D002415:Cats; D019902:Chondrocytes / Q000378:metabolism / Q000473:pathology; D005260:Female; D006811:Humerus / Q000378:metabolism / Q000473:pathology*; D008297:Male; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D010011:Osteocytes / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D059467:Transcriptome