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Dincel AS, Jørgensen NR. New Emerging Biomarkers for Bone Disease: Sclerostin and Dickkopf-1 (DKK1). Calcif Tissue Int 2023; 112:243-257. [PMID: 36165920 DOI: 10.1007/s00223-022-01020-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/26/2022] [Indexed: 01/25/2023]
Abstract
A healthy skeleton depends on a continuous renewal and maintenance of the bone tissue. The process of bone remodeling is highly controlled and consists of a fine-tuned balance between bone formation and bone resorption. Biochemical markers of bone turnover are already in use for monitoring diseases and treatment involving the skeletal system, but novel biomarkers reflecting specific biological processes in bone and interacting tissues may prove useful for diagnostic, prognostic, and monitoring purposes. The Wnt-signaling pathway is one of the most important pathways controlling bone metabolism and consequently the action of inhibitors of the pathway such as sclerostin and Dickkopf-related protein 1 (DKK1) have crucial roles in controlling bone formation and resorption. Thus, they might be potential markers for clinical use as they reflect a number of physiological and pathophysiological events in bone and in the cross-talk with other tissues in the human body. This review focuses on the clinical utility of measurements of circulating sclerostin and DKK1 levels based on preanalytical and analytical considerations and on evidence obtained from published clinical studies. While accumulating evidence points to clear associations with a number of disease states for the two markers, and thus, the potential for especially sclerostin as a biochemical marker that may be used clinically, the lack of standardization or harmonization of the assays still hampers the clinical utility of the markers.
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Affiliation(s)
- Aylin Sepinci Dincel
- Department of Medical Biochemistry, Faculty of Medicine, Gazi University, Ankara, Turkey
- Department of Clinical Biochemistry, Rigshospitalet, Valdemar Hansens Vej 13 Glostrup, 2600, Copenhagen, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Niklas Rye Jørgensen
- Department of Medical Biochemistry, Faculty of Medicine, Gazi University, Ankara, Turkey.
- Department of Clinical Biochemistry, Rigshospitalet, Valdemar Hansens Vej 13 Glostrup, 2600, Copenhagen, Denmark.
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Sclerostin: From Molecule to Clinical Biomarker. Int J Mol Sci 2022; 23:ijms23094751. [PMID: 35563144 PMCID: PMC9104784 DOI: 10.3390/ijms23094751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/12/2022] [Accepted: 04/22/2022] [Indexed: 12/23/2022] Open
Abstract
Sclerostin, a glycoprotein encoded by the SOST gene, is mainly produced by mature osteocytes and is a critical regulator of bone formation through its inhibitory effect on Wnt signaling. Osteocytes are differentiated osteoblasts that form a vast and highly complex communication network and orchestrate osteogenesis in response to both mechanical and hormonal cues. The three most commonly described pathways of SOST gene regulation are mechanotransduction, Wnt/β-catenin, and steroid signaling. Downregulation of SOST and thereby upregulation of local Wnt signaling is required for the osteogenic response to mechanical loading. This review covers recent findings concerning the identification of SOST, in vitro regulation of SOST gene expression, structural and functional properties of sclerostin, pathophysiology, biological variability, and recent assay developments for measuring circulating sclerostin. The three-dimensional structure of human sclerostin was generated with the AlphaFold Protein Structure Database applying a novel deep learning algorithm based on the amino acid sequence. The functional properties of the 3-loop conformation within the tertiary structure of sclerostin and molecular interaction with low-density lipoprotein receptor-related protein 6 (LRP6) are also reviewed. Second-generation immunoassays for intact/biointact sclerostin have recently been developed, which might overcome some of the reported methodological obstacles. Sclerostin assay standardization would be a long-term objective to overcome some of the problems with assay discrepancies. Besides the use of age- and sex-specific reference intervals for sclerostin, it is also pivotal to use assay-specific reference intervals since available immunoassays vary widely in their methodological characteristics.
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Cejka D. Cardiovascular Safety of Anti-Sclerostin Therapy in Chronic Kidney Disease. Metabolites 2021; 11:770. [PMID: 34822428 PMCID: PMC8624769 DOI: 10.3390/metabo11110770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 01/10/2023] Open
Abstract
The significance of sclerostin for bone and cardiovascular health in patients with chronic kidney disease (CKD) is complex and incompletely understood. Experimental evidence suggests that anti-sclerostin therapy shows diminished efficacy on bone in the setting of CKD. Limited clinical evidence suggests that the osteoanabolic and anti-resorptive activity is attenuated, but hypocalcemia is more prevalent in patients with advanced CKD (eGFR < 30 mL/min) treated with anti-sclerostin (romosozumab) therapy as compared to patients without kidney disease. Furthermore, sclerostin is prominently expressed in uremic arteries. Whether the inhibition of sclerostin has adverse effects on cardiovascular health in CKD is currently unknown. This review summarizes the current understanding of the physiology and pathophysiology of sclerostin in CKD, with a focus on the cardiovascular safety of anti-sclerostin therapy in patients with or without CKD.
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Affiliation(s)
- Daniel Cejka
- Department of Medicine III: Nephrology, Transplantation Medicine, Rheumatology, Geriatrics, Ordensklinikum Linz-Elisabethinen Hospital, Fadingerstraße 1, 4020 Linz, Austria
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Brandenburg VM, Verhulst A, Babler A, D'Haese PC, Evenepoel P, Kaesler N. Sclerostin in chronic kidney disease-mineral bone disorder think first before you block it! Nephrol Dial Transplant 2019; 34:408-414. [PMID: 29846712 DOI: 10.1093/ndt/gfy129] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 04/08/2018] [Indexed: 12/11/2022] Open
Abstract
Canonical Wnt signalling activity is a major player in physiological and adaptive bone metabolism. Wnt signalling is regulated by soluble inhibitors, with sclerostin being the most widely studied. Sclerostin's main origin is the osteocyte and its major function is blockade of osteoblast differentiation and function. Therefore, sclerostin is a potent inhibitor of bone formation and mineralization. Consequently, blocking sclerostin via human monoclonal antibodies (such as romosozumab) represents a promising perspective for the treatment of (postmenopausal) osteoporosis. However, sclerostin's physiology and the effects of sclerostin monoclonal antibody treatment are not limited to the skeleton. Specifically, the potential roles of sclerostin in chronic kidney disease (CKD) and associated pathologies covered by the term chronic kidney disease and mineral bone disorder (CKD-MBD), which also includes accelerated cardiovascular calcification, warrant specific attention. CKD-MBD is a complex disease condition in which sclerostin antibodies may interfere at different levels and influence the multiform interplay of hyperparathyroidism, renal osteodystrophy and vascular calcification, but the clinical sequelae remain obscure. The present review summarizes the potential effects of sclerostin blockade in CKD-MBD. We will address and summarize the urgent research targets that are being identified and that need to be addressed before a valid risk-benefit ratio can be established in the clinical setting of CKD.
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Affiliation(s)
- Vincent M Brandenburg
- Department of Cardiology, University Hospital of the RWTH Aachen, Aachen, Germany.,Department of Cardiology, Rhein-Maas Klinikum, Würselen, Germany
| | - Anja Verhulst
- Laboratory of Pathophysiology, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
| | - Anne Babler
- Department of Nephrology, University Hospital of the RWTH Aachen, Aachen, Germany
| | - Patrick C D'Haese
- Laboratory of Pathophysiology, Department of Biomedical Sciences, University of Antwerp, Wilrijk, Belgium
| | - Pieter Evenepoel
- Department of Immunology and Microbiology, Laboratory of Nephrology, KU Leuven and University Hospitals Leuven, Leuven, Belgium
| | - Nadine Kaesler
- Department of Nephrology, University Hospital of the RWTH Aachen, Aachen, Germany
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Kalousová M, Dusilová-Sulková S, Kuběna AA, Zakiyanov O, Tesař V, Zima T. Sclerostin levels predict cardiovascular mortality in long-term hemodialysis patients: A prospective observational cohort study. Physiol Res 2019; 68:547-558. [PMID: 31177791 DOI: 10.33549/physiolres.934034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Sclerostin is a protein which is involved in bone metabolism and probably also in vessel wall function. This prospective observational cohort study evaluated the prognostic significance of sclerostin in hemodialysis (HD) patients. In total, 106 HD patients and 25 healthy controls participated in the study. HD patients were prospectively followed up for five years. Sclerostin was measured in serum using standard ELISA kits by Biomedica. Sclerostin concentrations in serum were higher in HD patients compared to the controls (89.2±40.3 pmol/l vs. 32.8±13.0 pmol/l, p<0.001). Sclerostin levels were significant for cardiovascular mortality but not for overall mortality and mortality due to infection. A higher cardiovascular risk was connected to sclerostin concentrations above the median (>84 pmol/l), HR (95 % CI): 2.577 (1.0002-10.207), p=0.04. When sclerostin was evaluated together with residual diuresis in Kaplan-Meier analysis the worst prognosis due to cardiovascular events was observed in the group with high sclerostin and zero residual diuresis compared to all other patients (p=0.007). In summary, serum sclerostin levels in HD patients were increased when compared to healthy subjects. High sclerostin levels were demonstrated as a risk factor for cardiovascular mortality. Further studies are required to clarify the pathophysiological mechanisms of sclerostin action in patients with renal failure before therapeutic measures can be established.
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Affiliation(s)
- M Kalousová
- Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
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Appelman-Dijkstra NM, Papapoulos SE. Clinical advantages and disadvantages of anabolic bone therapies targeting the WNT pathway. Nat Rev Endocrinol 2018; 14:605-623. [PMID: 30181608 DOI: 10.1038/s41574-018-0087-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The WNT signalling pathway is a key regulator of bone metabolism, particularly bone formation, which has helped to define the role of osteocytes - the most abundant bone cells - as orchestrators of bone remodelling. Several molecules involved in the control of the WNT signalling pathway have been identified as potential targets for the development of bone-building therapeutics for patients with osteoporosis. Several of these molecules have been investigated in animal models, but only inhibitors of sclerostin (which is produced by osteocytes) have been investigated in phase III clinical studies. Here, we review the rationale for these developments and the specificity and potential off-target actions of WNT-based therapeutics. We also describe the available preclinical and clinical studies and discuss the benefits and risks of using sclerostin inhibitors for the management of patients with osteoporosis.
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Borawski J, Zoltko J, Labij-Reduta B, Koc-Zorawska E, Naumnik B. Effects of Enoxaparin on Intravascular Sclerostin Release in Healthy Men. J Cardiovasc Pharmacol Ther 2018; 23:344-349. [PMID: 29658328 DOI: 10.1177/1074248418770623] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sclerostin (Scl) is implicated in vascular calcification and angiogenesis and localizes within vasculature. Its molecule incorporates a heparin-binding site that implies also binding to endothelial glycocalyx. We preliminary tested whether intravenous (IV) low-molecular-weight heparin enoxaparin can stimulate intravascular release of this calcification inhibitor in humans. Sixteen male volunteers were injected with a bolus of 1 mg/kg body weight of enoxaparin. After 10 minutes, plasma immunoreactive Scl levels increased uniformly by a mean of 184% versus baseline level of 0.56 ± 0.17 ng/mL ( P = .0004). Plasma Scl levels were found still elevated after 2 and 6 hours (with a median of 20.9% and 8.69%, respectively) and became normal after 24 hours. The percentage of increase (Δ) in plasma Scl after 10 minutes was directly correlated with enoxaparin dose per kg/m2 of body mass index (ρ = 0.587, P = .017) and strongly inversely correlated with the preinjection Scl levels (ρ = -0.747, P = .0008). A robust negative association between the ΔScl increase after 10 minutes and the ΔScl decrease after 2 hours versus 10 minutes was observed (ρ = -0.835, P < .0001). Complementary in vitro spiking experiment showed no effects of enoxaparin addition and whole blood incubation on plasma Scl levels when measured with the immunoassay. This study shows that enoxaparin has a stimulating effect on the intravascular release of calcification inhibitor Scl in healthy men. This novel pharmacological action of the popular anticoagulant drug seems important in cardiovascular medicine.
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Affiliation(s)
- Jacek Borawski
- 1 First Department of Nephrology and Transplantation With Dialysis Unit, Medical University of Bialystok, Bialystok, Poland
| | - Justyna Zoltko
- 1 First Department of Nephrology and Transplantation With Dialysis Unit, Medical University of Bialystok, Bialystok, Poland
| | - Barbara Labij-Reduta
- 1 First Department of Nephrology and Transplantation With Dialysis Unit, Medical University of Bialystok, Bialystok, Poland
| | - Ewa Koc-Zorawska
- 1 First Department of Nephrology and Transplantation With Dialysis Unit, Medical University of Bialystok, Bialystok, Poland
| | - Beata Naumnik
- 1 First Department of Nephrology and Transplantation With Dialysis Unit, Medical University of Bialystok, Bialystok, Poland
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Delanaye P, Paquot F, Bouquegneau A, Blocki F, Krzesinski JM, Evenepoel P, Pottel H, Cavalier E. Sclerostin and chronic kidney disease: the assay impacts what we (thought to) know. Nephrol Dial Transplant 2017; 33:1404-1410. [DOI: 10.1093/ndt/gfx282] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 08/23/2017] [Indexed: 12/11/2022] Open
Affiliation(s)
- Pierre Delanaye
- Department of Nephrology, Dialysis, Hypertension, Transplantation, University of Liège (ULg CHU), CHU Sart Tilman, Liège, Belgium
| | - François Paquot
- Department of Nephrology, Dialysis, Hypertension, Transplantation, University of Liège (ULg CHU), CHU Sart Tilman, Liège, Belgium
| | - Antoine Bouquegneau
- Department of Nephrology, Dialysis, Hypertension, Transplantation, University of Liège (ULg CHU), CHU Sart Tilman, Liège, Belgium
| | - Frank Blocki
- Medical LIAISON Bone & Mineral, DiaSorin Inc, Stillwater, MN, USA
| | - Jean-Marie Krzesinski
- Department of Nephrology, Dialysis, Hypertension, Transplantation, University of Liège (ULg CHU), CHU Sart Tilman, Liège, Belgium
| | - Pieter Evenepoel
- Department of Nephrology and Renal Transplantation, University of Leuven, University Hospitals Leuven, Leuven, Belgium
| | - Hans Pottel
- Department of Public Health and Primary Care at Kulak, University of Leuven, Kortrijk, Belgium
| | - Etienne Cavalier
- Department of Clinical Chemistry, University of Liège, CHU Sart Tilman, Liège, Belgium
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Lombardi G, Barbaro M, Locatelli M, Banfi G. Novel bone metabolism-associated hormones: the importance of the pre-analytical phase for understanding their physiological roles. Endocrine 2017; 56:460-484. [PMID: 28181144 DOI: 10.1007/s12020-017-1239-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/17/2017] [Indexed: 02/08/2023]
Abstract
The endocrine function of bone is now a recognized feature of this tissue. Bone-derived hormones that modulate whole-body homeostasis, are being discovered as for the effects on bone of novel and classic hormones produced by other tissues become known. Often, however, the data regarding these last generation bone-derived or bone-targeting hormones do not give about a clear picture of their physiological roles or concentration ranges. A certain degree of uncertainty could stem from differences in the pre-analytical management of biological samples. The pre-analytical phase comprises a series of decisions and actions (i.e., choice of sample matrix, methods of collection, transportation, treatment and storage) preceding analysis. Errors arising in this phase will inevitably be carried over to the analytical phase where they can reduce the measurement accuracy, ultimately, leading discrepant results. While the pre-analytical phase is all important, in routine laboratory medicine, it is often not given due consideration in research and clinical trials. This is particularly true for novel molecules, such as the hormones regulating the endocrine function of bone. In this review we discuss the importance of the pre-analytical variables affecting the measurement of last generation bone-associated hormones and describe their, often debated and rarely clear physiological roles.
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Affiliation(s)
| | - Mosè Barbaro
- Laboratory Medicine Service, San Raffaele Hospital, Milano, Italy
| | | | - Giuseppe Banfi
- IRCCS Istituto Ortopedico Galeazzi, Milano, Italy
- Vita-Salute San Raffaele University, Milano, Italy
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Abstract
PURPOSE OF THE REVIEW Impaired bone quality contributes to the increased fracture risk in chronic kidney disease patients. Both low and high turnover bone disease may compromise bone quality. The question arises whether bone biomarkers may be additive or replace bone histormorphometry for diagnosing the extremes of bone turnover. RECENT FINDINGS Studies exploring the performance of established and emerging bone biomarkers against histomorphometric assessment of bone turnover are limited and overall yield inconclusive results as to their diagnostic utility. Bone biomarkers, although promising, currently fail to meet the needed diagnostic accuracy to replace bone histomorphometry and thus are not yet ready for clinical use. Bone biomarkers have not only several advantages, but also important limitations such as high biological variability, retention with kidney disease, preanalytical issues, and interassay variability. These important issues must be considered when developing and evaluating bone biomarkers. There is an urgent need for harmonization and standardization of available assays and additional bone biopsy studies.
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Affiliation(s)
- Pieter Evenepoel
- Department of Immunology and Microbiology, Laboratory of Nephrology, KU Leuven, 3000, Leuven, Belgium.
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, 3000, Leuven, Belgium.
| | - Etienne Cavalier
- Department of Clinical Chemistry, University of Liege, CHU de Liege, 4000, Liege, Belgium
| | - Patrick C D'Haese
- Department of Biomedical Sciences, Laboratory of Pathophysiology, Antwerp University, 2610, Wilrijk, Belgium
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Abstract
The Wnt/β-catenin signaling pathway plays an essential role in osteoblast biology. Sclerostin is a soluble antagonist of Wnt/β-catenin signaling secreted primarily by osteocytes. Current evidence indicates that sclerostin likely functions as a local/paracrine regulator of bone metabolism rather than as an endocrine hormone. Nonetheless, circulating sclerostin levels in humans often reflect changes in the bone microenvironment, although there may be exceptions to this observation. Using existing assays, circulating sclerostin levels have been shown to be altered in response to both hormonal stimuli and across a variety of normal physiological and pathophysiological conditions. In both rodents and humans, parathyroid hormone provided either intermittently or continuously suppresses sclerostin levels. Likewise, most evidence from both human and animal studies supports a suppressive effect of estrogen on sclerostin levels. Efforts to examine non-hormonal/systemic regulation of sclerostin have in general shown less consistent findings or have provided associations rather than direct interventional information, with the exception of mechanosensory studies which have consistently demonstrated increased sclerostin levels with skeletal unloading, and conversely decreases in sclerostin with enhanced skeletal loading. Herein, we will review the existent literature on both hormonal and non-hormonal/systemic factors which have been studied for their impact on sclerostin regulation.
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Affiliation(s)
- Matthew T Drake
- Department of Endocrinology, Kogod Center on Aging, Mayo Clinic College of Medicine, Rochester, MN, USA.
| | - Sundeep Khosla
- Department of Endocrinology, Kogod Center on Aging, Mayo Clinic College of Medicine, Rochester, MN, USA
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Costa AG, Cremers S, Bilezikian JP. Sclerostin measurement in human disease: Validity and current limitations. Bone 2017; 96:24-28. [PMID: 27742501 DOI: 10.1016/j.bone.2016.10.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 10/06/2016] [Accepted: 10/10/2016] [Indexed: 10/20/2022]
Abstract
Sclerostin a potent regulator of bone formation, is an antagonist of the Wnt-signaling pathway. The advent of assays to measure circulating sclerostin has enabled research to be performed with the aim to understand the potential role of circulating sclerostin as a pathophysiological marker in a variety of clinical settings. At this time, however, assays to measure circulating sclerostin are still relatively new and have not demonstrated consistent internal agreement in addition to which there are differences between serum and plasma levels. Nevertheless, measurement of sclerostin in the circulation has the potential to reflect the dynamics of bone formation with particular reference to situations in which osteocytes, the major source of circulating sclerostin, may be perturbed. Because of technical uncertainties regarding sclerostin assays that are currently available, circulating sclerostin measurements should be interpreted cautiously with attention to reference ranges for each assay and whether or not the measurement is made in serum or plasma.
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Affiliation(s)
- Aline G Costa
- Department of Medicine, Division of Endocrinology, Metabolic Bone Diseases Unit, College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - Serge Cremers
- Department of Medicine, Division of Endocrinology, Metabolic Bone Diseases Unit, College of Physicians and Surgeons, Columbia University, New York, NY, United States; Department of Pathology & Cell Biology, Division of Clinical Pathology College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - John P Bilezikian
- Department of Medicine, Division of Endocrinology, Metabolic Bone Diseases Unit, College of Physicians and Surgeons, Columbia University, New York, NY, United States.
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