title: Differences in non-enzymatic glycation and collagen cross-links between human cortical and cancellous bone.
abstract: It is important to establish the relationship between pentosidine and advanced glycation endproducts (AGEs) in bone. We found the relationship between pentosidine and AGEs and their magnitude of accumulation were dependent on bone's surface-to-volume ratio. Results illustrate the importance of measuring pentosidine and AGEs separately in cancellous and cortical bone.
  
  
  BACKGROUND
  Accumulation of collagen cross-links (AGEs) produced by non-enzymatic glycation deteriorates bone's mechanical properties and fracture resistance. Although a single AGE, pentosidine, is commonly used as a representative marker, it is unclear whether it quantitatively reflects total fluorescent AGEs in bone. The goal of this study was to establish the relationship between pentosidine and total AGEs in cancellous and cortical bone.
  
  
  METHODS
  Pentosidine and total AGEs were quantified in 170 human bone samples. Total fluorescent AGEs were measured in 28 additional cancellous and cortical bone specimens of the same apparent volume that were incubated in control or in vitro glycation solutions. Correlations between pentosidine and total AGEs and differences between cortical and cancellous groups were determined.
  
  
  RESULTS
  Pentosidine was correlated with total AGEs in cancellous bone (r = 0.53, p < 0.0001) and weakly correlated in cortical bone (r = 0.23, p < 0.05). There was more pentosidine (p < 0.01) and total AGEs (p < 0.001) in cancellous than in cortical bone. The in vitro glycation substudy showed that cancellous bone accumulated more AGEs than cortical bone (p < 0.05).
  
  
  CONCLUSIONS
  The relationship between pentosidine and total AGEs and their magnitude of accumulation differed in cancellous and cortical bone of the same apparent volume, and were dependent on the surface-to-volume ratios of each sample. It is important to consider the bone types as two separate entities, and it is crucial to quantify total AGEs in addition to pentosidine to allow for more comprehensive analysis of the effects of non-enzymatic glycation in bone.
authors.affiliation: Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, CBIS room 3137, 110 Eighth Street, Troy, NY 12180, USA.
authors.forename: L
authors.initials: L
authors.lastname: Karim
authors.forename: S Y
authors.initials: SY
authors.lastname: Tang
authors.forename: G E
authors.initials: GE
authors.lastname: Sroga
authors.forename: D
authors.initials: D
authors.lastname: Vashishth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D001120:Arginine / Q000031:analogs & derivatives* / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D001842:Bone and Bones / Q000737:chemistry* / Q000378:metabolism; D003094:Collagen / Q000378:metabolism*; D005260:Female; D005269:Femur / Q000737:chemistry; D017127:Glycation End Products, Advanced / Q000032:analysis*; D006801:Humans; D008239:Lysine / Q000031:analogs & derivatives* / Q000032:analysis; D008297:Male; D008875:Middle Aged; D013048:Specimen Handling / Q000379:methods; D013977:Tibia / Q000737:chemistry; D046509:Tissue Culture Techniques; D055815:Young Adult
chemical_list: D015415:Biomarkers; D017127:Glycation End Products, Advanced; D003094:Collagen; D001120:Arginine; C062187:pentosidine; D008239:Lysine