title: Bioactive silica nanoparticles reverse age-associated bone loss in mice.
abstract: We recently reported that in vitro, engineered 50nm spherical silica nanoparticles promote the differentiation and activity of bone building osteoblasts but suppress bone-resorbing osteoclasts. Furthermore, these nanoparticles promote bone accretion in young mice in vivo. We have now investigated the capacity of these nanoparticles to reverse bone loss in aged mice, a model of human senile osteoporosis. Aged mice received nanoparticles weekly and bone mineral density (BMD), bone structure, and bone turnover were quantified. Our data revealed a significant increase in BMD, bone volume, and biochemical markers of bone formation. Biochemical and histological examinations failed to identify any abnormalities caused by nanoparticle administration. Our studies demonstrate that silica nanoparticles effectively blunt and reverse age-associated bone loss in mice by a mechanism involving promotion of bone formation. The data suggest that osteogenic silica nanoparticles may be a safe and effective therapeutic for counteracting age-associated bone loss.
  
  
  BACKGROUND
  Osteoporosis poses a significant problem in the society. Based on their previous in-vitro findings, the authors' group investigated the effects of spherical silica nanoparticles in reversing bone loss in a mouse model of osteoporosis. The results showed that intra-peritoneal injections of silica nanoparticles could increase bone mineral density, with little observed toxic side effects. This novel method may prove important in future therapy for combating osteoporosis.
authors: The Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia 30033, USA.|Emory University, Department of Medicine, Division of Endocrinology, Atlanta, Georgia, 30322, USA.|The Winship Cancer Institute, Emory University School of Medicine, Atlanta GA 30322, USA.
authors: M Neale
authors: MN
authors: Weitzmann
authors: Emory University, Department of Medicine, Division of Endocrinology, Atlanta, Georgia, 30322, USA.
authors: Shin-Woo
authors: SW
authors: Ha
authors: Emory University, Department of Medicine, Division of Endocrinology, Atlanta, Georgia, 30322, USA.
authors: Tatyana
authors: T
authors: Vikulina
authors: The Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia 30033, USA.|Emory University, Department of Medicine, Division of Endocrinology, Atlanta, Georgia, 30322, USA.
authors: Susanne
authors: S
authors: Roser-Page
authors: Department of Chemistry, Seoul National University, Seoul 151-747, Korea.
authors: Jin-Kyu
authors: JK
authors: Lee
authors: The Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia 30033, USA.|Emory University, Department of Medicine, Division of Endocrinology, Atlanta, Georgia, 30322, USA.|The Winship Cancer Institute, Emory University School of Medicine, Atlanta GA 30322, USA.
authors: George R
authors: GR
authors: Beck
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015519:Bone Density / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D006801:Humans; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry*; D010006:Osteoblasts / Q000000981:diagnostic imaging / Q000378:metabolism; D010010:Osteoclasts / Q000000981:diagnostic imaging / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism; D011859:Radiography; D012822:Silicon Dioxide / Q000737:chemistry / Q000494:pharmacology
chemical_list: D015415:Biomarkers; D012822:Silicon Dioxide
keywords: Aging; Bone formation; Osteoporosis; Silica nanoparticles; Toxicity