title: Comparative Effects of Ibandronate and Paclitaxel on Immunocompetent Bone Metastasis Model.
abstract: OBJECTIVE
  Bone metastasis invariably increases morbidity and mortality. This study compares the effects of ibandronate and paclitaxel on bone structure and its mechanical properties and biochemical turnover in resorption markers using an immunocompetent Walker 256-Sprague-Dawley model, which was subjected to tumor-induced osteolysis.
  
  
  METHODS
  Seventy rats were divided equally into 4 groups: 1) sham group (SHAM), 2) tumor group (CANC), 3) ibandronate treated group (IBAN), and 4) paclitaxel treated group (PAC). Morphological indices [bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp)] and mechanical properties (failure load, stiffness) were evaluated after thirty days of treatment period. Bone resorption rate was analysed using serum deoxypyridinoline (Dpd) concentrations.
  
  
  RESULTS
  Morphological indices showed that ibandronate (anti-resorptive drug) had a better effect in treating tumor-induced architectural changes in bone than paclitaxel (chemotherapeutic drug). The deterioration in bone architecture was reflected in the biomechanical properties of bone as studied with decreased failure load (F(x)) and stiffness (S) of the bone on the 30th day postsurgery. Dpd concentrations were significantly lower in the IBAN group, indicating successful inhibition of bone resorption and destruction.
  
  
  CONCLUSIONS
  Ibandronate was found to be as effective as higher doses of paclitaxel in maintaining stiffness of bone. Paclitaxel treatment did not appear to inhibit osteoclast resorption, which is contrary to earlier in-vitro literature. Emphasis should be placed on the use of immunocompetent models for examining drug efficacy since it adequately reflects bone metastasis in clinical scenarios.
authors.affiliation: Department of Endocrinology & Metabolism, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Yoon-Sok
authors.initials: YS
authors.lastname: Chung
authors.affiliation: Department of Medical Biotechnology, Dongguk University, Seoul, Korea.
authors.forename: Ho Chul
authors.initials: HC
authors.lastname: Kang
authors.affiliation: Department of Medical Biotechnology, Dongguk University, Seoul, Korea. tlee@dongguk.edu.
authors.forename: Taeyong
authors.initials: T
authors.lastname: Lee
mesh_terms: D000596:Amino Acids; D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects* / Q000502:physiology; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D001859:Bone Neoplasms / Q000188:drug therapy*; D001862:Bone Resorption / Q000139:chemically induced*; D004164:Diphosphonates / Q000494:pharmacology*; D000077557:Ibandronic Acid; D007121:Immunocompetence; D008297:Male; D009362:Neoplasm Metastasis; D010014:Osteolysis; D017239:Paclitaxel / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000596:Amino Acids; D004164:Diphosphonates; C036020:deoxypyridinoline; D017239:Paclitaxel; D000077557:Ibandronic Acid
keywords: Tumor-induced osteolysis; biomechanical properties; immunocompetent rodent model; micro-CT