title: Increased prevalence of bisphosphonate-related osteonecrosis of the jaw with vitamin D deficiency in rats.
abstract: Necrotic bone exposure in the oral cavity has recently been reported in patients treated with nitrogen-containing bisphosphonates as part of their therapeutic regimen for multiple myeloma or metastatic cancers to bone. It has been postulated that systemic conditions associated with cancer patients combined with tooth extraction may increase the risk of osteonecrosis of the jaw (ONJ). The objective of this study was to establish an animal model of bisphosphonate-related ONJ by testing the combination of these risk factors. The generation of ONJ lesions in rats resembling human disease was achieved under the confluence of intravenous injection of zoledronate (ZOL; 35 microg/kg every 2 weeks), maxillary molar extraction, and vitamin D deficiency [VitD(-)]. The prevalence of ONJ in the VitD(-)/ZOL group was 66.7%, which was significantly higher (p < .05, Fisher exact test) than the control (0%), VitD(-) (0%), and ZOL alone (14.3%) groups. Similar to human patients, rat ONJ lesions prolonged the oral exposure of necrotic bone sequestra and were uniquely associated with pseudoepitheliomatous hyperplasia. The number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end label-positive (TUNEL(+)) osteoclasts significantly increased on the surface of post-tooth extraction alveolar bone of the VitD(-)/ZOL group, where sustained inflammation was depicted by [(18)F]fluorodeoxyglucose micro-positron emission tomography (microPET). ONJ lesions were found to be associated with dense accumulation of mixed inflammatory/immune cells. These cells, composed of neutrophils and lymphocytes, appeared to juxtapose apoptotic osteoclasts. It is suggested that the pathophysiologic mechanism(s) underpinning ONJ may involve the interaction between bisphosphonates and compromised vitamin D functions in the realm of skeletal homeostasis and innate immunity.
authors.affiliation: The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA 90095-1668, USA.
authors.forename: Akishige
authors.initials: A
authors.lastname: Hokugo
authors.forename: Russell
authors.initials: R
authors.lastname: Christensen
authors.forename: Evelyn M
authors.initials: EM
authors.lastname: Chung
authors.forename: Eric C
authors.initials: EC
authors.lastname: Sung
authors.forename: Alan L
authors.initials: AL
authors.lastname: Felsenfeld
authors.forename: James W
authors.initials: JW
authors.lastname: Sayre
authors.forename: Neal
authors.initials: N
authors.lastname: Garrett
authors.forename: John S
authors.initials: JS
authors.lastname: Adams
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nishimura
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D004164:Diphosphonates / Q000008:administration & dosage / Q000009:adverse effects* / Q000097:blood / Q000494:pharmacology; D004195:Disease Models, Animal; D005269:Femur / Q000187:drug effects / Q000473:pathology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000494:pharmacology; D007249:Inflammation / Q000235:genetics / Q000473:pathology; D007571:Jaw Diseases / Q000209:etiology* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D010010:Osteoclasts / Q000187:drug effects / Q000473:pathology; D010012:Osteogenesis / Q000187:drug effects; D010020:Osteonecrosis / Q000209:etiology* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014081:Tooth Extraction / Q000009:adverse effects; D014807:Vitamin D / Q000008:administration & dosage / Q000494:pharmacology; D014808:Vitamin D Deficiency / Q000150:complications*; D000077211:Zoledronic Acid
chemical_list: D004164:Diphosphonates; D007093:Imidazoles; D014807:Vitamin D; D000077211:Zoledronic Acid