title: Bone impairment in oxalosis: An ultrastructural bone analysis.
abstract: Deposition of calcium oxalate crystals in the kidney and bone is a hallmark of systemic oxalosis. Since the bone compartment can store massive amounts of oxalate, patients present with recurrent low-trauma fractures, bone deformations, severe bone pains and specific oxalate osteopathy on plain X-ray. Bone biopsy from the iliac crest displays specific features such as oxalate crystals surrounded by a granulomatous reaction due to an invasion of bone surface by macrophages. We present data obtained in 10 samples from 8 patients with oxalosis (16-68 years) who underwent iliac crest bone biopsy and bone quality analysis using modern methods (microradiography, microindentation, Fourier Transform InfraRed Microspectroscopy, transmission electron microscopy) in addition to histomorphometry. Disseminated calcium oxalate deposits (whewellite) were found in the bone marrow space (with a granulomatous reaction) but not in the bone matrix. Calcium oxalate deposits were totally surrounded by macrophages and multinucleated giant cells, and a phagocytosis activity was sometimes observed. Very few calcium oxalate crystals were directly in close contact with the mineral substance of the bone. Bone mineralization was not modified by the presence of calcium oxalate even in close vicinity. Bone quality analysis also revealed a harder bone than normal, perhaps in relationship with decreased carbonate content in the mineral. This increase in bone hardness could explain a more "brittle" bone. In patients with oxalosis, the formation and growth of calcium oxalate crystals in the bone appeared independent of apatite. The mechanisms leading to nucleation and growth of oxalate deposits are still unclear and deserve further studies.
authors.affiliation: Service de Néphrologie, Rhumatologie et Dermatologie Pédiatriques, Centre de Référence des Maladies Rénales Rares, Hôpital Femme Mère Enfant, Bron, France; INSERM, UMR 1033, Lyon, France; Université de Lyon, Lyon France. Electronic address: justine.bacchetta@chu-lyon.fr.
authors.forename: Justine
authors.initials: J
authors.lastname: Bacchetta
authors.affiliation: INSERM, UMR 1033, Lyon, France; Université de Lyon, Lyon France. Electronic address: delphine.farlay@inserm.fr.
authors.forename: Delphine
authors.initials: D
authors.lastname: Farlay
authors.affiliation: Université de Lyon, Lyon France; Service de Chirurgie Orthopédique Pédiatrique, Hôpital Femme Mère Enfant, Bron, France. Electronic address: kgenevois@gmail.com.
authors.forename: Kariman
authors.initials: K
authors.lastname: Abelin-Genevois
authors.affiliation: Service de Néphrologie, CHU, Rouen, France. Electronic address: ludivine.lebourg@chu-rouen.fr.
authors.forename: Ludivine
authors.initials: L
authors.lastname: Lebourg
authors.affiliation: Service de Néphrologie, Rhumatologie et Dermatologie Pédiatriques, Centre de Référence des Maladies Rénales Rares, Hôpital Femme Mère Enfant, Bron, France; Université de Lyon, Lyon France. Electronic address: pierre.cochat@chu-lyon.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Cochat
authors.affiliation: INSERM, UMR 1033, Lyon, France; Université de Lyon, Lyon France. Electronic address: georges.boivin@univ-lyon1.fr.
authors.forename: Georges
authors.initials: G
authors.lastname: Boivin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002113:Calcification, Physiologic / Q000502:physiology*; D002129:Calcium Oxalate / Q000032:analysis / Q000378:metabolism; D005260:Female; D006801:Humans; D006959:Hyperoxaluria / Q000175:diagnosis* / Q000378:metabolism*; D007085:Ilium / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure*; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D002129:Calcium Oxalate
keywords: Apatite crystals; Bone biopsy; Bone imaging; Calcium oxalate crystals; Primary hyperoxaluria