title: Collagen atomic scale molecular disorder in ochronotic cartilage from an alkaptonuria patient, observed by solid state NMR.
abstract: In pilot studies of the usefulness of solid state nuclear magnetic resonance spectroscopy in characterizing chemical and molecular structural effects of alkaptonuria on connective tissue, we have obtained (13) C spectra from articular cartilage from an AKU patient. An apparently normal anatomical location yielded a cross polarization magic angle spinning spectrum resembling literature spectra and dominated by collagen and glycosaminoglycan signals. All spectral linewidths from strongly pigmented ochronotic cartilage however were considerably increased relative to the control indicating a marked increase in collagen molecular disorder. This disordering of cartilage structural protein parallels, at the atomic level, the disordering revealed at higher length scales by microscopy. We also demonstrate that the abnormal spectra from ochronotic cartilage fit with the abnormality in the structure of collagen fibres at the ultrastructural level, whereby large ochronotic deposits appear to alter the structure of the collagen fibre by invasion and cross linking.
  
  
  CONCLUSIONS
  Increased signal linewidths in solid state NMR spectra of ochronotic articular cartilage from an AKU patient relative to linewidths in normal, control, cartilage reveals a marked decrease in collagen molecular order in the diseased tissue. This atomic level disordering parallels higher length scale disorder revealed by microscopic techniques.
authors: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
authors: Wing Ying
authors: WY
authors: Chow
authors: Adam M
authors: AM
authors: Taylor
authors: David G
authors: DG
authors: Reid
authors: James A
authors: JA
authors: Gallagher
authors: Melinda J
authors: MJ
authors: Duer
mesh_terms: D000368:Aged; D000474:Alkaptonuria / Q000150:complications*; D002357:Cartilage Diseases / Q000209:etiology / Q000473:pathology*; D002358:Cartilage, Articular / Q000737:chemistry* / Q000648:ultrastructure; D003094:Collagen / Q000032:analysis* / Q000737:chemistry / Q000648:ultrastructure*; D005260:Female; D006025:Glycosaminoglycans / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009794:Ochronosis / Q000000981:diagnostic imaging* / Q000209:etiology; D010865:Pilot Projects; D014463:Ultrasonography
chemical_list: D006025:Glycosaminoglycans; D003094:Collagen