title: Combining μX-ray fluorescence, μXANES and μXRD to shed light on Zn2+ cations in cartilage and meniscus calcifications.
abstract: We aimed to examine the presence of Zn, a trace element, in osteoarthritis (OA) cartilage and meniscus from patients undergoing total knee joint replacement for primary OA. We mapped Ca(2+) and Zn(2+) at the mesoscopic scale by X-ray fluorescence microanalysis (μX-ray) to determine the spatial distribution of the 2 elements in cartilage, μX-ray absorption near edge structure spectroscopy to identify the Zn species, and μX-ray diffraction to determine the chemical nature of the calcification. Fourier transform infrared spectroscopy was used to determine the chemical composition of cartilage and meniscus. Ca(2+) showed a heterogeneous spatial distribution corresponding to the calcifications within cartilage (or meniscus) or at their surface. At least 2 Zn(2+) species were present: the first may correspond to Zn embedded in protein (different Zn metalloproteins are known to prevent calcification in biological tissues), and the second may be associated with a Zn trap in or at the surface of the calcification. Calcification present in OA cartilage may significantly modify the spatial distribution of Zn; part of the Zn may be trapped in the calcification and may alter the associated biological function of Zn metalloproteins.
authors.affiliation: Laboratoire de Physique des Solides, CNRS UMR 8502, Paris Sud University, Orsay, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Dessombz
authors.forename: Christelle
authors.initials: C
authors.lastname: Nguyen
authors.forename: Hang-Korng
authors.initials: HK
authors.lastname: Ea
authors.forename: Stephan
authors.initials: S
authors.lastname: Rouzière
authors.forename: Eddy
authors.initials: E
authors.lastname: Foy
authors.forename: Didier
authors.initials: D
authors.lastname: Hannouche
authors.forename: Solene
authors.initials: S
authors.lastname: Réguer
authors.forename: Frederic-Emmanuel
authors.initials: FE
authors.lastname: Picca
authors.forename: Dominique
authors.initials: D
authors.lastname: Thiaudière
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lioté
authors.forename: Michel
authors.initials: M
authors.lastname: Daudon
authors.forename: Dominique
authors.initials: D
authors.lastname: Bazin
mesh_terms: D000368:Aged; D002358:Cartilage, Articular / Q000737:chemistry* / Q000473:pathology; D002412:Cations / Q000032:analysis; D006801:Humans; D007719:Knee Joint / Q000737:chemistry* / Q000473:pathology; D008027:Light; D008297:Male; D008592:Menisci, Tibial / Q000737:chemistry* / Q000473:pathology; D010003:Osteoarthritis / Q000473:pathology; D013052:Spectrometry, X-Ray Emission; D056928:X-Ray Absorption Spectroscopy; D014961:X-Ray Diffraction; D015032:Zinc / Q000032:analysis*
chemical_list: D002412:Cations; D015032:Zinc
keywords: Ca phosphate apatites; Ca pyrophosphate; Osteoarthritis; Zn environment; μX-ray absorption spectroscopy