title: Local renin-angiotensin system is associated with bone mineral density of glucocorticoid-induced osteoporosis patients.
abstract: The local renin-angiotensin system (RAS) is closely related to bone metabolism. However, it is unknown whether the local RAS is related to bone mineral density (BMD) in glucocorticoid-induced osteoporosis (GIOP). Here, we revealed that the two main characteristics of GIOP might inhibit bone formation and enhance bone resorption.
  
  
  BACKGROUND
  The aim of this study is to assess the expression of the main RAS components in the trabecular bone of lumbar vertebrae in GIOP and analyze the relationship between the major RAS components and BMD.
  
  
  METHODS
  We collected 96 inpatient cases of lumbar disc herniation from patients who underwent dual-energy X-ray absorptiometry examinations followed by surgical treatment in our hospital. Patients were divided into the GIOP group (n = 48) and control group (n = 48). The circulating and local expression levels of the main RAS components were examined. The correlation between the main RAS components and BMD was then analyzed.
  
  
  RESULTS
  The mRNA expression of local bone angiotensin type 1 and 2 receptors (AT1R and AT2R, respectively) and RANKL was higher in the GIOP group compared with the control group (p < 0.001), but there was no difference in the circulating protein levels between groups (p > 0.05). Multiple logistic regression analysis revealed that AT1R and AT2R expression and the RANKL/OPG ratio in local bone were negatively associated with BMD (p < 0.001, odds ratio (OR) 1.236, 95 % confidence interval (CI) 1.207-1.333; p < 0.001, OR 1.971, 95% CI 1.809-2.233; and p < 0.001, OR 1.676, 95% CI 1.546-1.845, respectively).
  
  
  CONCLUSIONS
  This study provides evidence that the role of local RAS is related to BMD in GIOP patients, and suggests that local RAS might influence RANKL/OPG signaling to modulate bone metabolism.
authors.affiliation: Department of Integrated Traditional Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
authors.forename: B
authors.initials: B
authors.lastname: Shuai
authors.forename: Y P
authors.initials: YP
authors.lastname: Yang
authors.forename: L
authors.initials: L
authors.lastname: Shen
authors.forename: R
authors.initials: R
authors.lastname: Zhu
authors.forename: X J
authors.initials: XJ
authors.lastname: Xu
authors.forename: C
authors.initials: C
authors.lastname: Ma
authors.forename: L
authors.initials: L
authors.lastname: Lv
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.forename: J H
authors.initials: JH
authors.lastname: Rong
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000187:drug effects*; D001862:Bone Resorption / Q000139:chemically induced; D016022:Case-Control Studies; D005260:Female; D005938:Glucocorticoids / Q000009:adverse effects*; D006801:Humans; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010012:Osteogenesis / Q000187:drug effects; D010024:Osteoporosis / Q000139:chemically induced*; D053245:RANK Ligand / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D044139:Receptor, Angiotensin, Type 2 / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000187:drug effects*; D016896:Treatment Outcome
chemical_list: D005938:Glucocorticoids; D053245:RANK Ligand; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2