title: Phenotypic characterization of osteoarthritic osteocytes from the sclerotic zones: a possible pathological role in subchondral bone sclerosis.
abstract: Subchondral bone sclerosis is a well-recognised manifestation of osteoarthritis (OA). The osteocyte cell network is now considered to be central to the regulation of bone homeostasis; however, it is not known whether the integrity of the osteocyte cell network is altered in OA patients. The aim of this study was to investigate OA osteocyte phenotypic changes and its potential role in OA subchondral bone pathogenesis. The morphological and phenotypic changes of osteocytes in OA samples were investigated by micro-CT, SEM, histology, immunohistochemistry, TRAP staining, apoptosis assay and real-time PCR studies. We demonstrated that in OA subchondral bone, the osteocyte morphology was altered showing rough and rounded cell body with fewer and disorganized dendrites compared with the osteocytes in control samples. OA osteocyte also showed dysregulated expression of osteocyte markers, apoptosis, and degradative enzymes, indicating that the phenotypical changes in OA osteocytes were accompanied with OA subchondral bone remodelling (increased osteoblast and osteoclast activity) and increased bone volume with altered mineral content. Significant alteration of osteocytes identified in OA samples indicates a potential regulatory role of osteocytes in subchondral bone remodelling and mineral metabolism during OA pathogenesis.
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Anjali
authors.initials: A
authors.lastname: Jaiprakash
authors.forename: Indira
authors.initials: I
authors.lastname: Prasadam
authors.forename: Jian Q
authors.initials: JQ
authors.lastname: Feng
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Ross
authors.initials: R
authors.lastname: Crawford
authors.forename: Yin
authors.initials: Y
authors.lastname: Xiao
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000368:Aged; D017209:Apoptosis; D016723:Bone Remodeling; D002452:Cell Count; D048430:Cell Shape; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007527:Isoenzymes / Q000032:analysis; D008297:Male; D020782:Matrix Metalloproteinases / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000473:pathology*; D010011:Osteocytes / Q000201:enzymology / Q000473:pathology*; D010026:Osteosclerosis / Q000209:etiology / Q000473:pathology*; D010641:Phenotype; D060888:Real-Time Polymerase Chain Reaction; D013194:Staining and Labeling; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D007527:Isoenzymes; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D020782:Matrix Metalloproteinases