title: Expression levels of estrogen receptor α mRNA in peripheral blood cells are an independent biomarker for postmenopausal osteoporosis.
abstract: BACKGROUND
  The up- and down-regulation of the osteoclastogenesis response depends on the estrogen/estrogen receptor (ER) signaling pathway. Previous reports have shown that the promoter hypermethylation and gene polymorphism of ERα are risks for menopausal osteoporosis. No previous study has evaluated the expression levels of ERα mRNA in menopausal osteoporosis using human subjects. We hypothesized that ERα mRNA expression may show less resistance to postmenopausal osteoporosis.
  
  
  METHODS
  In this study, we enrolled 107 women older than 45 years without menstruation and classified them into control, osteopenia, and osteoporosis groups depending on their T-scores. The ERα mRNA levels in peripheral blood cells (PBCs) were analyzed via quantitative real-time reverse-transcription polymerase chain reaction (QRT-PCR), and estrogen in the serum was detected via ELISA.
  
  
  RESULTS
  ERα mRNA levels in PBCs had a negative correlation with age and a positive correlation with estrogen and BAP in the osteopenia and osteoporosis groups, but not in the control group. Additionally, multivariate analysis showed that older age (> 55 years), and low ERα mRNA levels in PBLs (≦ 250.39 copies/μg DNA) were associated with an approximately 9.188-, and 31.25-fold risk of osteoporosis.
  
  
  CONCLUSIONS
  We conclude that ERα mRNA levels in PBLs could be used as an independent risk factor for postmenopausal osteoporosis.
  
  
  CONCLUSIONS
  Our findings suggested that ERα mRNA levels in PBLs may be more important than age and serum estrogen levels.
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Orthopedic Surgery, National Taiwan University Hospital Yun-Lin Branch, Taiwan.
authors.forename: Chi-Wen
authors.initials: CW
authors.lastname: Chou
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Orthopedic Surgery, National Taiwan University Hospital Yun-Lin Branch, Taiwan; Department of Nursing, College of Medicine & Nursing, Hung Kuang University, Taichung, Taiwan; Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Technology, Taipei Medical University, Taichung, Taiwan.
authors.forename: Tsay-I
authors.initials: TI
authors.lastname: Chiang
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Orthopedic Surgery, National Taiwan University Hospital Yun-Lin Branch, Taiwan.
authors.forename: I-Chang
authors.initials: IC
authors.lastname: Chang
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Chung-Hung
authors.initials: CH
authors.lastname: Huang
authors.affiliation: Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Technology, Taipei Medical University, Taichung, Taiwan.
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Cheng
keywords: Bone mineral density; Estrogen; Estrogen receptor; Osteoporosis