title: Autoimmune arthritis deteriorates bone quantity and quality of periarticular bone in a mouse model of rheumatoid arthritis.
abstract: This study showed that autoimmune arthritis induces especially severe osteoporosis in the periarticular region adjacent to inflamed joints, suggesting that arthritis increases the fragility fracture risk near inflamed joints, which is frequently observed in patients with RA.
  
  
  
  Periarticular osteoporosis near inflamed joints is a hallmark of early rheumatoid arthritis (RA). Here we show that rheumatic inflammation deteriorates the bone quality and bone quantity of periarticular bone, thereby decreasing bone strength and toughness in a mouse model of RA.
  
  
  
  Female BALB/c mice and SKG mice, a mutant mouse model of autoimmune arthritis on the BALB/c background, were used. At 12 weeks of age, BALB/c mice underwent either Sham surgery or bilateral ovariectomy (OVX), and SKG mice underwent intraperitoneal injection of mannan to induce arthritis. Eight weeks later, the mice were killed and the femurs and tibias were subjected to micro-computed tomography, Fourier transform infrared (FTIR) spectroscopic imaging, X-ray diffraction, histology, and mechanical testing.
  
  
  
  SKG mice developed significant trabecular bone loss in both the distal metaphysis of the femur and the lumbar vertebral body, but the extent of the bone loss was more severe in the distal metaphysis. Neither SKG nor OVX mice exhibited changes in the geometry and matrix properties of the diaphysis of the femur, whereas SKG mice, but not OVX mice, did exhibit changes in these properties in the distal metaphysis of the femur. Bone strength and fracture toughness of the distal metaphysis of the tibia adjacent to the inflamed ankle joint were significantly decreased in SKG mice.
  
  
  
  Autoimmune arthritis induces periarticular osteoporosis, characterized by deterioration of cortical bone geometry and quality as well as by trabecular bone loss, leading to severe bone fragility in periarticular bone adjacent to inflamed joints.
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan. takamasa@med.hokudai.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Takahata
authors.affiliation: Chitose Institute of Science and Technology, Chitose, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kimura-Suda
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kameda
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.|Division of Human Mechanical Systems and Design, Faculty of Engineering, Hokkaido University, Sapporo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Endo
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Hamano
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hiratsuka
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ota
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Sato
authors.affiliation: Chitose Institute of Science and Technology, Chitose, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.affiliation: Division of Human Mechanical Systems and Design, Faculty of Engineering, Hokkaido University, Sapporo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Todoh
authors.affiliation: Division of Human Mechanical Systems and Design, Faculty of Engineering, Hokkaido University, Sapporo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tadano
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Iwasaki
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology; D001862:Bone Resorption / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D010052:Ovariectomy; D012720:Severity of Illness Index; D055114:X-Ray Microtomography
keywords: Bone fragility; Bone quality; Cortical bone; Rheumatoid arthritis (RA)