Calcium phosphate microcrystal deposition in the human intervertebral disc.
A variety of crystals have been identified in both normal and pathological connective tissues. Calcium phosphate 'cuboidal' microcrystal deposition has been found, using transmission electron microscopy (TEM), in femoral articular cartilage, where they are distributed as a band 5-50 microm beneath the articular surface. These cuboid microcrystals have been identified as magnesium whitlockite. Our objective was to investigate their presence in the human intervertebral disc. In this study, two degenerate and 15 scoliotic discs were examined using light microscopy and TEM techniques to determine the presence of calcium phosphate crystals. Calcium pyrophosphate dihydrate (CPPD) deposition was identified in one degenerate disc specimen. Using TEM and electron probe analysis, cuboid microcrystals were identified in the annulus fibrosus and nucleus pulposus of both degenerate specimens, but not in the discs from young scoliotic patients. Cuboid microcrystal deposition was found predominantly around cells, which were mainly necrotic, with some association with extracellular lipidic/membranous debris. This is the first TEM report of whitlockite in the intervertebral disc. In one specimen coexistence of cuboid and CPPD crystal deposition was found.
Lee
Robert S
RS
Institute of Orthopaedics, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK. leerobert9@hotmail.com
Kayser
Mike V
MV
Ali
S Yousuf
SY
D000328:Adult; D000368:Aged; D001672:Biocompatible Materials / Q000032:analysis; D002130:Calcium Phosphates / Q000032:analysis*; D002131:Calcium Pyrophosphate / Q000032:analysis; D002648:Child; D003460:Crystallization; D004577:Electron Probe Microanalysis / Q000379:methods; D006801:Humans; D007403:Intervertebral Disc / Q000737:chemistry* / Q000473:pathology; D007592:Joint Diseases / Q000473:pathology; D008274:Magnesium / Q000032:analysis; D008854:Microscopy, Electron / Q000379:methods; D009336:Necrosis; D012600:Scoliosis / Q000473:pathology; D013168:Spondylolisthesis / Q000473:pathology
D001672:Biocompatible Materials; D002130:Calcium Phosphates; C021767:whitlockite; C020243:calcium phosphate; D008274:Magnesium; D002131:Calcium Pyrophosphate