title: Bone marrow sFRP5 level is negatively associated with bone formation markers.
abstract: Secreted frizzled-related protein 5 (sFRP5) level in bone marrow environment is inversely correlated with bone formation markers, suggesting that it decreases bone mass by inhibiting bone formation. Besides, it functions in a local fashion when regulating bone metabolism. sFRP5 may be a target when developing anti-osteoporotic agents.
  
  
  
  The purpose of the study is to investigate the relationship between bone marrow sFRP5 level and bone turnover state.
  
  
  
  Eighty-three total knee arthroplasty patients were enrolled in this study. Data were collected prospectively and reviewed retrospectively. Lumbar spine and femoral neck bone mineral density (BMD), marrow adipose tissue (MAT) sFRP5 messenger RNA (mRNA) expression level, sFRP5 concentrations in marrow fluid and serum, concentrations of bone formation and resorption markers were measured for each participant.
  
  
  
  Marrow fluid sFRP5 concentration was positively correlated with both MAT sFRP5 expression (p = 0.040) and serum sFRP5 concentration (p = 0.043). Significantly positive correlation existed between MAT sFRP5 expression level and BMD (p < 0.05). Marrow fluid sFRP5 concentration had a moderate but not significant positive association with BMD. MAT sFRP5 was negatively related to serum bone formation markers including N-terminal propeptide of type 1 procollagen (P1NP) (p = 0.011), osteocalcin (OC), and alkaline phosphatase (ALP). Marrow fluid and serum sFRP5 concentrations also had mild negative correlations with bone formation markers but reached no significance. There was no significant correlation between bone resorption marker β-crosslaps (β-CTX) and sFRP5. The mRNA expression level of MAT sFRP5 was positively related with those of MAT leptin, peroxisome proliferator-activated receptor-γ (PPARγ), and adiponectin, and its correlation with leptin was statistically significant (p = 0.026).
  
  
  
  Bone marrow sFRP5 level is closely correlated with BMD and bone formation markers. sFRP5 may be a potential negative regulator of bone mass by inhibiting bone formation. It may exert its effects on bone metabolism in a paracrine, rather than endocrine manner.
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuanjiagang, Yuzhong District, Chongqing, 400016, China. chhong113@126.com.
authors.forename: H
authors.identifier: 0000-0002-4152-624X
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuanjiagang, Yuzhong District, Chongqing, 400016, China.
authors.forename: Y
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Rehabilitation, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: D
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuanjiagang, Yuzhong District, Chongqing, 400016, China.
authors.forename: G
authors.initials: G
authors.lastname: Dai
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuanjiagang, Yuzhong District, Chongqing, 400016, China.
authors.forename: C
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuanjiagang, Yuzhong District, Chongqing, 400016, China.
authors.forename: W
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Yuanjiagang, Yuzhong District, Chongqing, 400016, China.
authors.forename: D
authors.initials: D
authors.lastname: Jiang
mesh_terms: D015502:Absorptiometry, Photon; D048868:Adaptor Proteins, Signal Transducing; D000273:Adipose Tissue / Q000378:metabolism; D000368:Aged; D000375:Aging / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology; D001853:Bone Marrow / Q000378:metabolism*; D016723:Bone Remodeling / Q000502:physiology; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005272:Femur Neck / Q000503:physiopathology; D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D010012:Osteogenesis / Q000502:physiology*; D010024:Osteoporosis / Q000378:metabolism* / Q000503:physiopathology; D012333:RNA, Messenger / Q000235:genetics; D012189:Retrospective Studies; D000094742:Secreted Frizzled-Related Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015415:Biomarkers; D005136:Eye Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; C118511:SFRP5 protein, human; D000094742:Secreted Frizzled-Related Proteins
keywords: Bone metabolism; Bone mineral density; Marrow adipose tissue; sFRP5