U A, Papassotiriou I, Michalakakou K, Fessatou S, Fandridis E, Papachristou G, Terpos E: High levels of synovial fluid osteoprotegerin (OPG) and elevated serum ratio of receptor activator of nuclear factorkappaB ligand (RANKL) to OPG correlate with illness severity in sufferers with major knee osteoarthritis. Clin Biochem 2008, 41:746-749. 18. Fc Receptor-like 3 Proteins web Nelson AE, Fang F, Shi XA, Kraus VB, Stabler T, Renner JB: Failure of serum transforming growth factor-beta (TGF-beta1) as a biomarker of radiographic osteoarthritis at the knee and hip: a cross-sectional analysis in the Johnston County Osteoarthritis Project. Osteoarthritis Cartilage 2009, 17:772-776. 19. Niehrs C: Function and biological roles in the Dickkopf household of Wnt modulators. Oncogene 2006, 25:7469-7481. 20. Grotewold L, Theil T, R her U: Expression pattern of Dkk-1 through mouse limb development. Mech Dev 1999, 89:151-153. 21. Grotewold L, R her U: Bmp, Fgf and Wnt signalling in programmed cell death and chondrogenesis for the duration of CD29/Integrin beta-1 Proteins MedChemExpress vertebrate limb improvement: the part of Dickkopf-1. Int J Dev Biol 2002, 46:943-947.Conclusions This study has revealed a significant decrease in plasma Dkk-1 of OA individuals and illustrated a pronounced inverse correlation with the degree of radiographic severity in individuals with key knee OA. The information of this study assistance the finding that Dkk-1 might be a beneficial prognostic parameter to reflect the disease severity of main knee OA. Furthermore, Dkk-1 levels in plasma had been directly correlated with those in synovial fluid. This study has been the initial to investigate such a correlation and additional studies is going to be essential to define the mechanisms underlying this association. Extra investigations might be needed to shed light around the possible function of Dkk-1 involved in the pathogenesis of chronic degenerative joint disorder, using the aim of developing powerful pharmacological agents to delay the progression to osteoarthritis.Abbreviations ANCOVA: analysis of co-variance; ANOVA: evaluation of variance; BMI: body mass index; CI: self-confidence intervals; DKK-1: Dickkopf-1; ELISA: enzyme-linked immunosorbent assay; KL: Kellgren and Lawrence; LDL: low-density lipoprotein; LRP: low-density lipoprotein receptor-related proteins; OA: osteoarthritis; ROC: receiver-operating characteristic; SD: common deviation; SPSS: statistical package for social sciences; WNT: Wingless. Acknowledgements This analysis was supported by the Ratchadapiseksompotch Fund, Faculty of Medicine, Chulalongkorn University, the Thailand Investigation Fund, the Commission on Higher Education, as well as the National Analysis Council of Thailand. The authors also would prefer to thank Prof. Yong Poovorawan and Ms. Petra Hirsch for reviewing the manuscript, Ms. Piyanuch Bumrungpanichthaworn for technical help, Mr.Wasan Punyasang for statistical guidance, and the Chulalongkorn Health-related Investigation Center (ChulaMRC) for kindly supplying facilities. Author specifics 1 Division of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand. 2Department of Orthopaedics, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand. Authors’ contributions SH was responsible for the conception and design and style in the study, the analysis and interpretation in the data, and drafting in the manuscript. AT, PY, and SN performed operations, acquired patients, and contributed to the sample collection. NS and ST assisted sample collection and data evaluation. All authors have read and approved the f.
