title: Differences in extracellular matrix proteins between Friesian horses with aortic rupture, unaffected Friesians and Warmblood horses.
abstract: BACKGROUND
  Unlike in Warmblood horses, aortic rupture is quite common in Friesian horses, in which a hereditary trait is suspected. The aortic connective tissue in affected Friesians shows histological changes such as medial necrosis, elastic fibre fragmentation, mucoid material accumulation and fibrosis with aberrant collagen morphology. However, ultrastructural examination of the collagen fibres of the mid-thoracic aorta has been inconclusive in further elucidating the pathogenesis of the disease.
  
  
  OBJECTIVE
  To assess several extracellular matrix (ECM) components biochemically in order to explore a possible underlying breed-related systemic ECM defect in Friesians with aortic rupture.
  
  
  METHODS
  Cadaver study.
  
  
  METHODS
  Tissues from affected Friesians (n = 18), unaffected Friesians (n = 10) and Warmblood horses (n = 30) were compared. Samples were taken from the thoracic aorta at the level of the rupture site, from two locations caudal to the rupture and from the deep digital flexor tendon. Total collagen content, post-translational modifications of collagen formation including lysine hydroxylation, and hydroxylysylpyridinoline (HP), lysylpyridinoline (LP) and pyrrole cross-links were analysed. Additionally, elastin cross-links, glycosaminoglycan content and matrix metalloproteinase (MMP) activity were assessed.
  
  
  RESULTS
  Significantly increased MMP activity and increased LP and HP cross-linking, lysine hydroxylation and elastin cross-linking were found at the site of rupture in affected Friesians. These changes may reflect processes involved in healing and aneurysm formation. Unaffected Friesians had less lysine hydroxylation and pyrrole cross-linking within the tendons compared with Warmblood horses. No differences in the matrix of the aorta were found between normal Warmbloods and Friesian horses.
  
  
  CONCLUSIONS
  Small sample size.
  
  
  CONCLUSIONS
  The differences in collagen parameters in tendon tissue may reflect differences in connective tissue metabolism between Friesians and Warmblood horses.
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Ploeg
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Gröne
authors.affiliation: Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.|Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
authors.forename: C H A
authors.initials: CHA
authors.lastname: van de Lest
authors.affiliation: Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: V
authors.initials: V
authors.lastname: Saey
authors.affiliation: Department of Comparative Physiology and Biometrics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Duchateau
authors.affiliation: Institute for Pathology, University of Veterinary Medicine Foundation, Hannover, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Wolsein
authors.affiliation: Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Chiers
authors.affiliation: Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Ducatelle
authors.affiliation: Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
authors.forename: P R
authors.initials: PR
authors.lastname: van Weeren
authors.affiliation: Equine Clinic, Oldeholtpade, the Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: de Bruijn
authors.affiliation: Department of Comparative Physiology and Biometrics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Delesalle
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology*; D001019:Aortic Rupture / Q000378:metabolism / Q000662:veterinary*; D003094:Collagen; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D006025:Glycosaminoglycans; D006734:Horse Diseases / Q000378:metabolism*; D006736:Horses
chemical_list: D016326:Extracellular Matrix Proteins; D006025:Glycosaminoglycans; D003094:Collagen
keywords: Friesian horse; aorta; collagen; elastin; extracellular matrix; glycosaminoglycans; horse