title: Expression of the calcium-sensing receptor in monocytes from synovial fluid is increased in osteoarthritis.
abstract: OBJECTIVE
  We assessed calcium-sensing receptor (CaSR) expression in monocytes isolated from synovial fluid of patients with different types of rheumatisms and explored whether CaSR expression was related to the inflammatory nature of synovial fluid.
  
  
  METHODS
  Forty-one patients were included: osteoarthritis (n=10), microcristallin rheumatisms (n=10), rheumatoid arthritis (n=12) and other inflammatory rheumatisms (n=9). Surface and total CaSR expressions in monocytes isolated from synovial fluid and blood were assessed by flow cytometry analysis. U937 cells were cultured during 24hours in presence of cell-free synovial fluids.
  
  
  RESULTS
  Every monocyte population tested express the CaSR intra- and extracellularly. Whereas similar pattern of CaSR expression exist in monocyte isolated from blood or synovial fluids, our results indicate that higher CaSR expression levels can be observed in monocytes from synovial fluids than in circulating monocytes. In both populations of monocytes, surface and total CaSR expressions were found to be significantly increased in patients with osteoarthritis compared to rheumatoid arthritis. Similar data were obtained when U937 cells were incubated with cell-free synovial fluids from osteoarthritis patients. Still present, this effect was significantly lowered when "inflammatory" synovial fluids were introduced in culture.
  
  
  CONCLUSIONS
  Our results indicate that CaSR expression in synovial derived monocytes is higher in osteoarthritis than in inflammatory rheumatisms and that CaSR expression is modulated by the nature of the synovial fluid. Given the role played by monocytes in the pathogenesis of chronic rheumatisms, monocytes could be interesting therapeutic targets via the CaSR.
authors.affiliation: Department of Rheumatology, University Hospital Amiens, 1, place Victor-Pauchet, 80000 Amiens, France; Inserm U1088, University of Picardie Jules-Verne, CURS site CHU Sud, 80054 Amiens cedex 1, France. Electronic address: sejourne.alice@chu-amiens.fr.
authors.forename: Alice
authors.initials: A
authors.lastname: Séjourné
authors.affiliation: Inserm U1088, University of Picardie Jules-Verne, CURS site CHU Sud, 80054 Amiens cedex 1, France.
authors.forename: Cédric
authors.initials: C
authors.lastname: Boudot
authors.affiliation: Inserm U1088, University of Picardie Jules-Verne, CURS site CHU Sud, 80054 Amiens cedex 1, France.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Objois
authors.affiliation: Department of Rheumatology, University Hospital Amiens, 1, place Victor-Pauchet, 80000 Amiens, France; Inserm U1088, University of Picardie Jules-Verne, CURS site CHU Sud, 80054 Amiens cedex 1, France.
authors.forename: Patrice
authors.initials: P
authors.lastname: Fardellone
authors.affiliation: Inserm U1088, University of Picardie Jules-Verne, CURS site CHU Sud, 80054 Amiens cedex 1, France; Department of Endocrine and Bone Biology, University Hospital Amiens, CHU Sud, 80054 Amiens cedex 1, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Brazier
authors.affiliation: Inserm U1088, University of Picardie Jules-Verne, CURS site CHU Sud, 80054 Amiens cedex 1, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Six
authors.affiliation: Inserm U1088, University of Picardie Jules-Verne, CURS site CHU Sud, 80054 Amiens cedex 1, France; Department of Biochemistry, University Hospital Amiens, CHU Sud, 80054 Amiens cedex 1, France.
authors.forename: Saïd
authors.initials: S
authors.lastname: Kamel
authors.affiliation: Inserm U1088, University of Picardie Jules-Verne, CURS site CHU Sud, 80054 Amiens cedex 1, France; Department of Endocrine and Bone Biology, University Hospital Amiens, CHU Sud, 80054 Amiens cedex 1, France.
authors.forename: Romuald
authors.initials: R
authors.lastname: Mentaverri
authors.affiliation: Department of Rheumatology, University Hospital Amiens, 1, place Victor-Pauchet, 80000 Amiens, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Goëb
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001168:Arthritis / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D010003:Osteoarthritis / Q000378:metabolism; D010865:Pilot Projects; D044169:Receptors, Calcium-Sensing / Q000096:biosynthesis*; D013582:Synovial Fluid / Q000378:metabolism*; D020298:U937 Cells; D055815:Young Adult
chemical_list: D044169:Receptors, Calcium-Sensing
keywords: Calcium-sensing receptor; Flow cytometry; Monocytes; Osteoarthritis; Rheumatoid arthritis; Synovial fluid