| 1. |
- Bratengeier, Cornelia, et al.
(författare)
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High shear stress amplitude in combination with prolonged stimulus duration determine induction of osteoclast formation by hematopoietic progenitor cells
- 2020
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Ingår i: The FASEB Journal. - : FEDERATION AMER SOC EXP BIOL. - 0892-6638 .- 1530-6860. ; 34:3, s. 3755-3772
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Tidskriftsartikel (refereegranskat)abstract
- To date, it is unclear how fluid dynamics stimulate mechanosensory cells to induce an osteoprotective or osteodestructive response. We investigated how murine hematopoietic progenitor cells respond to 2 minutes of dynamic fluid flow stimulation with a precisely controlled sequence of fluid shear stresses. The response was quantified by measuring extracellular adenosine triphosphate (ATP), immunocytochemistry of Piezo1, and sarcoplasmic/endoplasmic Ca2+ reticulum ATPase 2 (SERCA2), and by the ability of soluble factors produced by mechanically stimulated cells to modulate osteoclast differentiation. We rejected our initial hypothesis that peak wall shear stress rate determines the response of hematopoietic progenitor cells to dynamic fluid shear stress, as it had only a minor correlation with the abovementioned parameters. Low stimulus amplitudes corresponded to activation of Piezo1, SERCA2, low concentrations of extracellular ATP, and inhibition of osteoclastogenesis and resorption area, while high amplitudes generally corresponded to osteodestructive responses. At a given amplitude (3 Pa) and waveform (square), the duration of individual stimuli (duty cycle) showed a strong correlation with the release of ATP and osteoclast number and resorption area. Collectively, our data suggest that hematopoietic progenitor cells respond in a viscoelastic manner to loading, since a combination of high shear stress amplitude and prolonged duty cycle is needed to trigger an osteodestructive response. Plain Language Summary In case of painful joints or missing teeth, the current intervention is to replace them with an implant to keep a high-quality lifestyle. When exercising or chewing, the cells in the bone around the implant experience mechanical loading. This loading generally supports bone formation to strengthen the bone and prevent breaking, but can also stimulate bone loss when the mechanical loading becomes too high around orthopedic and dental implants. We still do not fully understand how cells in the bone can distinguish between mechanical loading that strengthens or weakens the bone. We cultured cells derived from the bone marrow in the laboratory to test whether the bone loss response depends on (i) how fast a mechanical load is applied (rate), (ii) how intense the mechanical load is (amplitude), or (iii) how long each individual loading stimulus is applied (duration). We mimicked mechanical loading as it occurs in the body, by applying very precisely controlled flow of fluid over the cells. We found that a mechanosensitive receptor Piezo1 was activated by a low amplitude stimulus, which usually strengthens the bone. The potential inhibitor of Piezo1, namely SERCA2, was only activated by a low amplitude stimulus. This happened regardless of the rate of application. At a constant high amplitude, a longer duration of the stimulus enhanced the bone-weakening response. Based on these results we deduce that a high loading amplitude tends to be bone weakening, and the longer this high amplitude persists, the worse it is for the bone.
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| 2. |
- Bratengeier, Cornelia, et al.
(författare)
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Mechanical loading intensities affect the release of extracellular vesicles from mouse bone marrow-derived hematopoietic progenitor cells and change their osteoclast-modulating effect
- 2024
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Ingår i: The FASEB Journal. - : WILEY. - 0892-6638 .- 1530-6860. ; 38:1
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Tidskriftsartikel (refereegranskat)abstract
- Low-intensity loading maintains or increases bone mass, whereas lack of mechanical loading and high-intensity loading decreases bone mass, possibly via the release of extracellular vesicles by mechanosensitive bone cells. How different loading intensities alter the biological effect of these vesicles is not fully understood. Dynamic fluid shear stress at low intensity (0.7 +/- 0.3 Pa, 5 Hz) or high intensity (2.9 +/- 0.2 Pa, 1 Hz) was used on mouse hematopoietic progenitor cells for 2 min in the presence or absence of chemical compounds that inhibit release or biogenesis of extracellular vesicles. We used a Receptor activator of nuclear factor kappa-Beta ligand-induced osteoclastogenesis assay to evaluate the biological effect of different fractions of extracellular vesicles obtained through centrifugation of medium from hematopoietic stem cells. Osteoclast formation was reduced by microvesicles (10 000x g) obtained after low-intensity loading and induced by exosomes (100 000x g) obtained after high-intensity loading. These osteoclast-modulating effects could be diminished or eliminated by depletion of extracellular vesicles from the conditioned medium, inhibition of general extracellular vesicle release, inhibition of microvesicle biogenesis (low intensity), inhibition of ESCRT-independent exosome biogenesis (high intensity), as well as by inhibition of dynamin-dependent vesicle uptake in osteoclast progenitor cells. Taken together, the intensity of mechanical loading affects the release of extracellular vesicles and change their osteoclast-modulating effect. The intensity of mechanical loading strongly affects bone remodeling by either formation of bone or resorption of bone. Low-intensity loading on bone cells releases microvesicles that reduce formation of bone-resorbing osteoclasts, while high-intensity loading on bone cells releases exosomes that induce formation of bone-resorbing osteoclasts. The graphical abstract was created with image
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| 3. |
- Bratengeier, Cornelia, et al.
(författare)
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Mechanical loading releases osteoclastogenesis-modulating factors through stimulation of the P2X7 receptor in hematopoietic progenitor cells
- 2019
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Ingår i: Journal of Cellular Physiology. - : WILEY. - 0021-9541 .- 1097-4652. ; 234:8, s. 13057-13067
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Tidskriftsartikel (refereegranskat)abstract
- Mechanical instability of bone implants stimulate osteoclast differentiation and peri-implant bone loss, leading to prosthetic loosening. It is unclear which cells at the periprosthetic interface transduce mechanical signals into a biochemical response, and subsequently facilitate bone loss. We hypothesized that mechanical overloading of hematopoietic bone marrow progenitor cells, which are located near to the inserted bone implants, stimulates the release of osteoclast-inducing soluble factors. Using a novel in vitro model to apply mechanical overloading, we found that hematopoietic progenitor cells released adenosine triphosphate (ATP) after only 2min of mechanical loading. The released ATP interacts with its specific receptor P2X7 to stimulate the release of unknown soluble factors that inhibit (physiological loading) or promote (supraphysiological loading) the differentiation of multinucleated osteoclasts derived from bone marrow cultures. Inhibition of ATP-receptor P2X7 by Brilliant Blue G completely abolished the overloading-induced stimulation of osteoclast formation. Likewise, stimulation of P2X7 receptor on hematopoietic cells by BzATP enhanced the release of osteoclastogenesis-stimulating signaling molecules to a similar extent as supraphysiological loading. Supraphysiological loading affected neither gene expression of inflammatory markers involved in aseptic implant loosening (e.g., interleukin-1 (IL-1), IL-6, tumor necrosis factor-, and PTGES2) nor expression of the osteoclast modulators receptor activator of nuclear factor -B ligandand osteoprotegerin. Our findings suggest that murine hematopoietic progenitor cells are a potential key player in local mechanical loading-induced bone implant loosening via the ATP/P2X7-axis. Our approach identifies potential therapeutic targets to prevent prosthetic loosening.
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| 4. |
- Bratengeier, Cornelia, 1983-
(författare)
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Mechanisms of mechanically induced Osteoclastogenesis : in a novel in vitro model for bone implant loosening
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Total joint arthroplasty is the primary intervention in the treatment of end-stage osteoarthritis. Despite the high success rate, in some patients, the replacement will fail during their lifetime requiring a revision of the implant. These revisions are strenuous for the patient and costly for health care. Joint replacement at a younger age, in combination with a more active lifestyle, increases the need for an early revision of the joint prosthesis. The main reason for revision surgeries is aseptic loosening, a condition where the prosthesis is loosening due to bone degradation at the peri-prosthetic interface in the absence of infections. The most well-established pathological mechanism for aseptic loosening is related to wear particles, generated from different parts of the prosthesis that will trigger bone degradation and bone loss. In addition, early micromotions of the prosthesis and resulting local pressurized fluid flow in the peri-prosthetic interface (supraphysiological loading) have also been identified as a cause for aseptic loosening. However, it remains unknown what cells are the primary responders to supraphysiological loading, and what underlying physical, cellular and molecular mechanism that triggers osteoclast differentiation and osteolysis.In this thesis, we intended to shed light on three currently unknown aspects of mechanical loading-induced peri-prosthetic osteolysis, leading to aseptic loosening of orthopedic prostheses: (1)Which cells are the primary responder to supraphysiological loading? (2)What characteristics of the mechanical stimulus induce an osteo-protective or osteo-destructive response? (3)Which cellular mechano-sensing mechanisms are involved in an osteo-destructive response?We successfully implemented supraphysiological mechanical loading, mimicking the periprosthetic pressurized fluid flow around a loosening implant, in an in vitro model for bone implant loosening. Using this model, we uncovered the involvement of mesenchymal stem cells and myeloid progenitor cells (monocytes) in mechanical loading-induced peri-prosthetic osteolysis. Applying supraphysiological loading on cells from patients undergoing primary hip arthroplasty, successfully validated the in vitro model for the use of cells of human origin. We further identified in murine myeloid progenitor cells that a combination of high loading amplitude (3.0±0.2Pa), prolonged active loading duration per cycle (duty cycle 22%-50%), and rapid alterations in minimum/maximum values of the loading profile (square wave) is necessary to induce an osteo-destructive response. Further, the loading-induced ATP release and subsequent activation of the P2X7 receptor was essential for the release of soluble factors modulating osteoclastogenesis.In conclusion, we expect that the proposed new in vitro model is a helpful tool to further advance the knowledge in aseptic loosening, by uncovering the mechanoresponsive cellular mechanism to supraphysiological mechanical loading. The identification of the respondent cells in mechanical loading-induced prosthetic loosening gives the opportunity to deliver targeted treatment strategies. Furthermore, identifying the physical parameters that define the shift towards an osteo-destructive response emphasizes the importance of the prosthetic design and surgical technique to reduce mechanical loading-induced bone degradation around a prosthesis.
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| 5. |
- Bratengeier, Cornelia, 1983-, et al.
(författare)
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The release of osteoclast-stimulating factors on supraphysiological loading by osteoprogenitors coincides with expression of genes associated with inflammation and cytoskeletal arrangement
- 2022
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Ingår i: Scientific Reports. - : Springer. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Supraphysiological loading induced by unstable orthopedic implants initiates osteoclast formation, which results in bone degradation. We aimed to investigate which mechanosensitive cells in the peri-implant environment produce osteoclast-stimulating factors and how the production of these factors is stimulated by supraphysiological loading. The release of osteoclast-stimulating factors by different types of isolated bone marrow-derived hematopoietic and mesenchymal stem cells from six osteoarthritic patients was analyzed after one hour of supraphysiological loading (3.0 ± 0.2 Pa, 1 Hz) by adding their conditioned medium to osteoclast precursors. Monocytes produced factors that enhanced osteoclastogenesis by 1.6 ± 0.07-fold and mesenchymal stem cells by 1.4 ± 0.07-fold. Medium from osteoprogenitors and pre-osteoblasts enhanced osteoclastogenesis by 1.3 ± 0.09-fold and 1.4 ± 0.03-fold, respectively, where medium from four patients elicited a response and two did not. Next generation sequencing analysis of osteoprogenitors revealed that genes encoding for inflammation-related pathways and cytoskeletal rearrangements were regulated differently between responders and non-responders. Our data suggest that released osteoclast-stimulating soluble factors by progenitor cells in the bone marrow after supraphysiological loading may be related to cytoskeletal arrangement in an inflammatory environment. This connection could be relevant to better understand the aseptic loosening process of orthopedic implants.
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| 6. |
- Fahlgren, Anna, et al.
(författare)
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Biocompatibility of Polypyrrole with Human Primary Osteoblasts and the Effect of Dopants
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Polypyrrole (PPy) is a conducting polymer that enables controlled drug release upon electrical stimulation. We characterized the biocompatibility of PPy with human primary osteoblasts, and the effect of dopants. We investigated the biocompatibility of PPy comprising various dopants, i.e. p-toluene sulfonate (PPy-pTS), chondroitin sulfate (PPy-CS), or dodecylbenzenesulfonate (PPy-DBS), with human primary osteoblasts. PPy-DBS showed the roughest appearance of all surfaces tested, and its wettability was similar to the gold-coated control. The average number of attached cells was 45% higher on PPy-DBS than on PPyCS or PPy-pTS, although gene expression of the proliferation marker Ki-67 was similar in osteoblasts on all surfaces tested. Osteoblasts seeded on PPy-DBS or gold showed similar vinculin attachment points, vinculin area per cell area, actin filament structure, and Ferets diameter, while cells seeded on PPY-CS or PPY-pTS showed disturbed focal adhesions and were enlarged with disorganized actin filaments. Osteoblasts grown on PPy-DBS or gold showed enhanced alkaline phosphatase activity and osteocalcin gene expression, but reduced osteopontin gene expression compared to cells grown on PPy-pTS and PPy-CS. In conclusion, PPy doped with DBS showed excellent biocompatibility, which resulted in maintaining focal adhesions, cell morphology, cell number, alkaline phosphatase activity, and osteocalcin gene expression. Taken together, conducting polymers doped with DBS are well tolerated by osteoblasts. Our results could provide a basis for the development of novel orthopedic or dental implants with controlled release of antibiotics and pharmaceutics that fight infections or focally enhance bone formation in a tightly controlled manner.
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| 7. |
- Fahlgren, Anna, et al.
(författare)
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Supraphysiological loading induces osteocyte-mediated osteoclastogenesis in a novel in vitro model for bone implant loosening
- 2018
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Ingår i: Journal of Orthopaedic Research. - : WILEY. - 0736-0266 .- 1554-527X. ; 36:5, s. 1425-1434
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to develop an in vitro model for bone implant loosening, allowing analysis of biophysical and biological parameters contributing to mechanical instability-induced osteoclast differentiation and peri-implant bone loss. MLO-Y4-osteocytes were mechanically stimulated for 1h by fluid shear stress using regimes simulating: (i) supraphysiological loading in the peri-prosthetic interface (2.9 +/- 2.9Pa, 1Hz, square wave); (ii) physiologic loading in the cortical bone (0.7 +/- 0.7Pa, 5Hz, sinusoidal wave); and (iii) stress shielding. Cellular morphological parameters, membrane-bound RANKL expression, gene expression influencing osteoclast differentiation, nitric oxide release and caspase 3/7-activity were determined. Either Mouse bone marrow cells were cultured on top of loaded osteocytes or osteocyte-conditioned medium was added to bone marrow cells. Osteoclast differentiation was assessed after 6 days. We found that osteocytes subjected to supraphysiological loading showed similar morphology and caspase 3/7-activity compared to simulated physiological loading or stress shielding. Supraphysiological stimulation of osteocytes enhanced osteoclast differentiation by 1.9-fold compared to physiological loading when cell-to-cell contact was permitted. In addition, it enhanced the number of osteoclasts using conditioned medium by 1.7-fold, membrane-bound RANKL by 3.3-fold, and nitric oxide production by 3.2-fold. The stimulatory effect of supraphysiological loading on membrane-bound RANKL and nitric oxide production was higher than that achieved by stress shielding. In conclusion, the in vitro model developed recapitulated the catabolic biological situation in the peri-prosthetic interface during instability that is associated with osteoclast differentiation and enhanced RANKL expression. The model thus provides a platform for pre-clinical testing of pharmacological interventions with potential to stop instability-induced bone implant loosening. (c) 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1425-1434, 2018.
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| 8. |
- Gaudio, Agostino, et al.
(författare)
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Increased Sclerostin Serum Levels Associated with Bone Formation and Resorption Markers in Patients with Immobilization-Induced Bone Loss
- 2010
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 95:5, s. 2248-2253
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Tidskriftsartikel (refereegranskat)abstract
- Context: Sclerostin, a Wnt signaling antagonist on the osteoblasts produced by osteocytes, is regulated by mechanical strain and is implicated in the pathogenesis of disuse bone loss. There are no data on sclerostin in humans.Objective: The aim of the study was to evaluate sclerostin in patients immobilized after stroke, compared with control subjects, and to analyze its relationship with markers of bone formation and resorption.Design: This was a cross-sectional study.Setting and patients: We studied 40 postmenopausal women immobilized after a single episode of stroke 6 months or longer after onset, and 40 postmenopausal women from the general community. Bone status was assessed by quantitative ultrasound measurements at the calcaneus. Bone alkaline phosphatase (b-AP), carboxy-terminal telopeptide of type I collagen (CrossLaps), and sclerostin were evaluated by ELISA. We also used ELISA to measure serum levels of Dickkopf-1, another soluble inhibitor of Wnt/beta-catenin signaling, highly expressed by osteocytes.Results: Immobilized patients had higher sclerostin serum levels (median 0.975 ng/ml; 25th to 75th percentiles 0.662-1.490) than controls (median 0.300 ng/ml; 25th to 75th percentiles 0.165-0.400: P < 0.0001) and an increased bone turnover with a more significant rise in bone resorption (CrossLaps) than formation (b-AP) markers. Sclerostin correlated negatively with b-AP (r = -0.911; P < 0.0001) and positively with CrossLaps (r = 0.391; P = 0.012). Dickkopf-1 did not significantly differ between the groups. Patients also had quantitative ultrasound measurements index lower than controls (P < 0.001).Conclusions: This study shows for the first time that long-term immobilized patients present hypersclerostinemia associated with reduced bone formation, and suggests that sclerostin could be a link between mechanical unloading and disuse osteoporosis in humans.
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| 9. |
- Piemonte, S., et al.
(författare)
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Serum sclerostin levels decline in post-menopausal women with osteoporosis following treatment with intermittent parathyroid hormone
- 2012
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Ingår i: Journal of Endocrinological Investigation. - : Springer. - 0391-4097 .- 1720-8386. ; 35:9, s. 866-868
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study was carried out in order to evaluate the effect of 18-month treatment with PTH (1-34) or PTH (1-84) on serum sclerostin levels in humans.Subjects and methods: We investigated 10 women with severe osteoporosis, previously treated with alendronate and 20 untreated osteoporotic women. Subjects with severe osteoporosis were randomly divided into 2 groups of 5 patients each; the first group was treated with 20 μg of PTH (1-34) and the second one with 100 μg of PTH (1-84) according to an open-label design. Fasting blood samples were collected at baseline and at 2, 4, and 24 h after hormone administration. The same protocol was followed at month 1, 6, 12, 18. Serum sclerostin levels were measured at each time point by a sandwich-type enzyme-linked immunosorbent assay.Results: Basal serum sclerostin levels were not significantly different between patients previously treated with alendronate and those never treated. No significant acute change of serum sclerostin levels was observed after PTH administration. Fitting a mixed effect regression model, we found a significant time effect (p=0.0012) using the sclerostin level as the response variable and the month of drug administration as a single covariate. Treatment with both PTH molecules induced a monthly mean reduction of sclerostin levels of 0.1956 pmol/l.Conclusions: Our results indicate that long-term therapy with PTH (1-34) or PTH (1-84) in women with osteoporosis previously treated with alendronate is associated with a reduction in circulating sclerostin levels. This is a putative mechanism through which PTH performs its anabolic action.
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| 10. |
- Polyzos, S. A., et al.
(författare)
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Serum sclerostin levels positively correlate with lumbar spinal bone mineral density in postmenopausal women—the six-month effect of risedronate and teriparatide
- 2011
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Ingår i: Osteoporosis International. - : Springer. - 0937-941X .- 1433-2965. ; 23:3, s. 1171-1176
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Tidskriftsartikel (refereegranskat)abstract
- Summary: Sclerostin is expressed by osteocytes and inhibits bone formation by osteoblasts. In this study, serum sclerostin was positively correlated with either lumbar spinal bone mineral density or T-score. Furthermore, serum sclerostin was increased after 6 months treatment with risedronate, whereas remained unchanged after 6 months teriparatide treatment.Introduction: The primary aim of this study was the evaluation of serum sclerostin levels in postmenopausal women and their association with bone mineral density (BMD) and bone turnover markers. The secondary aim was the evaluation of treatment with either teriparatide (TPTD) or risedronate (RIS) on serum sclerostin levels in women with postmenopausal osteoporosis.Methods: Women with postmenopausal osteoporosis, assigned to receive either TPTD (TPTD group, n = 13) or RIS (RIS group, n = 36) for 6 months, and non-osteoporotic early postmenopausal women (NOEP group, n = 13) were recruited. Main outcome measure was serum sclerostin levels.Results: Serum sclerostin was higher in the NOEP group at baseline compared with either TPTD group (p = 0.007) or RIS group (p = 0.049). Sclerostin was positively correlated with both lumbar spinal (LS) BMD (r = 0.353; p = 0.005) and T-score (r = 0.501; p < 0.001) and negatively correlated with intact parathyroid hormone (r = −0.343; p = 0.024) at baseline. Multiple regression analysis showed that either LS BMD (Beta = 0.653; p = 0.018) or T-score (Beta = 0.711; p = 0.005) were independent predictors of serum sclerostin levels. No significant correlation was observed between serum sclerostin and bone turnover markers or estradiol at baseline. Sclerostin was significantly increased 6 months post-treatment in RIS group (p = 0.002), whereas remained statistically unaffected in the TPTD group.Conclusions: Serum sclerostin is decreased in women with postmenopausal osteoporosis compared with non-osteoporotic early postmenopausal women and is positively correlated to either LS BMD or LS T-score. Furthermore, serum sclerostin was increased after 6 months treatment with RIS, whereas remained essentially unchanged after 6 months TPTD treatment.
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| 11. |
- Terpos, Evangelos, et al.
(författare)
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Circulating Levels of the Wnt Inhibitors Dickkopf-1 and Sclerostin In Different Phases of Multiple Myeloma: Alterations Post-Therapy with Lenalidomide and Dexamethasone with or without Bortezomib
- 2010
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 116:21, s. 2963-2963
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Tidskriftsartikel (refereegranskat)abstract
- Dickkopf-1 (Dkk-1) and sclerostin are inhibitors of the Wingless-type and integrase 1 (Wnt) signaling and they are implicated in the pathogenesis of multiple myeloma (MM) bone disease through inhibition of osteoblast function. There is very limited information for the circulating levels of Dkk-1 and sclerostin in different phases of MM and their alterations post therapies with novel agents. Therefore, we studied 284 MM patients (153M/131F, median age 66 years): 167 consecutive patients were newly-diagnosed (20 had asymptomatic MM and 147 symptomatic MM), 29 patients were at the plateau phase of MM and 88 patients had relapsed/refractory MM and received therapy with the combination of lenalidomide plus dexamethasone with or without bortezomib (VRD or RD; Dimopoulos et al, Leukemia 2010). For newly diagnosed patients, serum was stored at the time of diagnosis, while for patients at the plateau phase serum was collected at the time of confirmation of the plateau (at least 6 months with stable M-protein without criteria confirming progression) and for relapsed/refractory patients on day 1 of cycles 1, 4 and 7 of VRD or RD administration. Circulating levels of Dkk-1 and sclerostin were measured using ELISA methodology (R&D Systems, Minneapolis, MN, USA and Biomedica Medizinprodukte, Vienna, Austria, respectively) in all patients and in 20 gender- and age- matched healthy controls. Circulating Dkk-1 and sclerostin concentrations of newly diagnosed symptomatic patients (median: 1383 pg/mL, range:274-32, 862 pg/mL and 415 pg/mL, 0–3,340 pg/mL respectively) were increased compared to controls (1069 pg/mL, 540-2, 709 pg/mL; p<0.001 and 250 pg/mL, 0–720 pg/mL; p=0.03, respectively) and to asymptomatic patients at diagnosis (1044 pg/mL, 480-2, 335 pg/mL; p<0.001 and 140 pg/mL, 0–1,100 pg/mL; p=0.001, respectively). Patients at plateau phase had increased circulating levels of sclerostin (704 pg/mL, 68–2000 pg/mL; p <0.001) compared to controls (p=0.002) as well as to MM patients at diagnosis (p=0.02). In contrast, they had lower serum levels of Dkk-1 (1013 pg/mL, 414–1729 pg/mL) compared to MM patients at diagnosis (p<0.001) and no difference compared to controls. Patients with ISS-3 myeloma at diagnosis had higher values of Dkk-1 and sclerostin than ISS-1 and ISS-2 patients [median Dkk-1 values for ISS-1, ISS-2 and ISS-3 were: 1059 pg/mL, 1290 pg/mL and 2649 pg/mL, respectively; p(ANOVA)=0.031; median sclerostin values for ISS-1, ISS-2 and ISS-3 were: 394 pg/mL, 392 pg/mL and 714 pg/mL, respectively; p(ANOVA)=0.001]. Patients with lytic disease at diagnosis (n=116) had increased levels of Dkk-1 compared with patients with no lytic disease (n=51): 1475 pg/mL, 327-32, 862 pg/mL vs. 840 pg/mL, 274–1112 pg/mL; p=0.002. There was no difference in sclerostin levels between these patients; however, patients with advanced bone disease (>3 lytic lesions and/or a fracture) had a borderline increase in their circulating sclerostin compared to all others (p=0.072). Dkk-1 circulating levels correlated weakly with sclerostin (r=0.201, p=0.05). Relapsed patients had increased Dkk-1 (1218 pg/mL, 161-19, 325 pg/mL) and sclerostin (886 pg/mL, 90-6, 272 pg/mL) levels compared to controls and to asymptomatic patients at diagnosis (p<0.001 for all comparisons). In patients who received RD, Dkk-1 was increased and sclerostin was decreased after 6 cycles of therapy. Responders to RD had a median increase of 9% in Dkk-1 serum levels after 6 cycles of therapy, while non-responders had a median increase of 91% compared to baseline values (p<0.01). Patients who did not respond to RD showed an increase in bone resorption marker CTX (p=0.021) after 6 cycles of therapy. VRD administration resulted in a significant reduction of sRANKL (p=0.024) and increase of bone formation marker, osteocalcin (p=0.01) after 6 cycles, but showed only minimal reduction of Dkk-1 (p=0.08) and no alterations on sclerostin. In conclusion our study suggests that Dkk-1 is elevated in active myeloma, while sclerostin is elevated even in the plateau phase of the disease. Both correlated with adverse disease features. The increase of Dkk-1 by RD seems to be balanced by a reduction effect of bortezomib on Dkk-1 in VRD. Furthermore, the reduction of sclerostin in RD patients may represent a modulatory effect of lenalidomide on marrow microenvironment. These results further support the rationale for the use of drugs targeting Dkk-1 and sclerostin in MM.
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| 12. |
- Terpos, E., et al.
(författare)
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Early effects of IL-6 receptor inhibition on bone homeostasis: a pilot study in women with rheumatoid arthritis
- 2011
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Ingår i: Clinical and Experimental Rheumatology. - Pisa, Italy : Clinical and Experimental Rheumatology. - 0392-856X .- 1593-098X. ; 29:6, s. 921-925
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: A critical role of interleukin-6 (IL-6) in bone homeostasis has been suggested in experimental studies. We examined whether inhibition of IL-6 receptor in patients with rheumatoid arthritis (RA) results in early alterations of circulating markers of bone remodelling.Methods: Circulating levels of osteoprotegerin, receptor activator of nuclear factor-kappaB ligand (RANKL), Wnt signalling pathway inhibitors Dickkopf-1 (Dkk-1) and sclerostin, markers of bone resorption (C-terminal cross-linking telopeptide of collagen type-I (CTX), tartrate-resistant acid phosphatase isoform-5b) and bone formation (bone-specific alkaline-phosphatase, osteocalcin) were examined in 22 women with active RA before and after two monthly infusions of tocilizumab (8mg/kg each); 'healthy', non-osteopenic, 1:1 age-matched women served as controls.Results: At baseline, osteoprotegerin/RANKL ratio in patients was lower than controls by 5-fold; circulating osteoprotegerin correlated negatively with corresponding 28-joint-count disease activity scores and circulating RANKL correlated positively with C-reactive protein. Also, Dkk-1, sclerostin, CTX and osteocalcin levels were higher in RA than controls. After two months, osteoprotegerin/RANKL ratio increased, Dkk-1 decreased and sclerostin increased comparing to baseline; other markers did not change significantly. Increases of osteoprotegerin/RANKL ratio were more prominent in 10 patients who achieved remission or low disease activity after tocilizumab than in 12 patients who did not. In contrast, the significant alterations of both Wnt inhibitors were comparable between these patient subgroups.Conclusions: Anti-IL-6 therapy induced suppression of the inflammatory response affects rapidly the disrupted bone homeostasis in active RA. An additional, possibly specific, effect of IL-6 receptor inhibition on bone remodelling in humans should be further examined.
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| 13. |
- Terpos, Evangelos, et al.
(författare)
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Elevated circulating sclerostin correlates with advanced disease features and abnormal bone remodeling in symptomatic myeloma: Reduction post-bortezomib monotherapy
- 2011
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Ingår i: International Journal of Cancer. - : John Wiley & Sons. - 0020-7136 .- 1097-0215. ; 131:6, s. 1466-1471
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Tidskriftsartikel (refereegranskat)abstract
- Sclerostin is a Wingless and Int-1 inhibitor, which is produced by osteocytes and inhibits osteoblast-driven bone formation. Sclerostin is implicated in the pathogenesis of bone loss in metabolic bone disorders but there is no information for its effect on multiple myeloma (MM)-related osteolytic disease. We evaluated circulating sclerostin in 157 newly diagnosed patients with symptomatic myeloma, in 25 with relapsed myeloma who received bortezomib monotherapy, in 21 patients with monoclonal gammopathy of undetermined significance (MGUS), and in 21 healthy controls. Patients with active myeloma had elevated circulating sclerostin compared to MGUS patients and controls (p < 0.01). MM patients who presented with fractures at diagnosis (n = 34) had very high levels of circulating sclerostin compared with all others (p < 0.01), whereas sclerostin correlated negatively with bone specific alkaline phosphatase (a bone formation marker; r = -0.541, p < 0.0001) and positively with C-telopeptide of collagen type-1 (a bone resorption marker; r = 0.524, p < 0.0001). Patients with International Staging System (ISS)-3 disease had higher circulating sclerostin compared to ISS-1 and ISS-2 MM (p = 0.001). Furthermore, patients with high sclerostin (upper quartile, n = 40) had a median survival of 27 months versus 98 months of all others (p = 0.031). Relapsed MM patients had higher levels of circulating sclerostin even compared to newly diagnosed patients (p < 0.01). Bortezomib monotherapy resulted in a reduction of sclerostin by almost 50% in both responders and non-responders. These results suggest that patients with active myeloma have elevated circulating sclerostin, which correlated with advanced disease features including severe bone disease. Our study indicates sclerostin as a possible target for the development of novel therapies to enhance osteoblast function in myeloma.
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| 14. |
- Terpos, Evangelos, et al.
(författare)
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High Serum Sclerostin Correlates with Advanced Stage, Increased Bone Resorption, Reduced Osteoblast Function, and Poor Survival in Newly-Diagnosed Patients with Multiple Myeloma.
- 2009
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 114:22, s. 425-425
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Tidskriftsartikel (refereegranskat)abstract
- Multiple myeloma (MM) is characterized by the presence of lytic bone disease due to increased osteoclast activity which is accompanied by reduced osteoblast function. To-date dickkopf-1 (Dkk-1) is considered as the main osteoblast inhibitor which is overproduced by myeloma cells and inhibits Wnt signaling leading to osteoblast exhaustion. Sclerostin is another canonical Wnt antagonist through its binding to low-density lipoprotein-receptor-related protein 5/6. Sclerostin is specifically expressed by osteocytes and inhibits bone morphogenic protein-induced osteoblast differentiation and ectopic bone formation. Osteonectin (SPARC) is a multi-faceted protein that belongs to a family of matricellular proteins. It is secreted by osteoblasts during bone formation, initiating mineralization and promoting mineral crystal formation. SPARC shows affinity for collagen in addition to bone mineral calcium. The aim of this study contacted by the Greek Myeloma Study Group in collaboration with Biomarker Design Forschungs GmbH (BDF), Vienna, Austria was to evaluate, for the first time in the literature, the serum levels of sclerostin in patients with MM and explore possible correlations with clinical and laboratory data, including SPARC levels, ISS stage and survival. One hundred and fifty-seven patients (87M/70F, median age 68 years) with MM at diagnosis before the administration of any type of therapy, including bisphosphonates, were evaluated. Serum sclerostin and SPARC were measured using an ELISA methodology developed by BDF for Biomedica Medizinprodukte GmbH & Co KG (Vienna, Austria). Both assays are sandwich type ELISA using biotinylated antibodies/HRP-streptavidine for the detection of sclerostin and SPARC in the serum. The detection limit of the sclerostin ELISA was 0.18 ng/ml and the coefficient of variation (CV) 6%. The standard range was set from 0.3-3 ng/ml. For the SPARC ELISA we found a detection limit of 1.95 ng/ml and CVs of 8% using a standard range from 5-130 ng/ml. Serum sclerostin and SPARC were determined in MM patients, 21 patients with MGUS and 21 healthy controls, of similar gender and age. Bone remodeling was also studied by the measurement of a series of serum indices within one week from diagnosis: i) osteoclast regulators [sRANKL and osteoprotegerin (OPG)], ii) Dkk-1, iii) bone resorption markers [C-terminal cross-linking telopeptide of collagen type-I (CTX) and 5b-isoenzyme of tartrate resistant acid phosphatase (TRACP-5b)], and iv) bone formation markers [bone-specific alkaline phosphatase (bALP) and osteocalcin (OC)]. Patients with MM had increased levels of serum sclerostin compared with MGUS patients (mean value±SD: 0.48±0.46 vs. 0.26±0.29 ng/ml; p=0.004) and healthy controls (0.31±0.20 ng/ml, p=0.01). In contrast, both patients with MM and MGUS had reduced levels of serum SPARC (26.3±16.2 and 27.2±18.0 ng/ml, respectively) compared to controls (52.8±50.2 ng/ml; p<0.001). Sclerostin values strongly correlated with beta2-microglobulin (r=0.354, p<0.0001), cystatin-C (r=0.389, p<0.0001), serum creatinine (r=0.380, p<0.0001), and bALP (r=-0.541, p<0.0001). No correlations were observed between sclerostin with sRANKL, OPG, Dkk-1 or SPARC. Patients with advanced bone disease assessed by conventional radiography (>3 lytic lesions and/or a pathological fracture) had a borderline increase of sclerostin compared to all others (median value: 0.51 vs. 0.41 ng/ml, p=0.09). Patients with ISS-3 disease had increased levels of sclerostin compared to patients with ISS-1 and ISS-2 MM (ANOVA p=0.001). Median survival of MM patients was 48 months and median follow-up period was 20 months. Patients who had a serum sclerostin of ≥0.62 ng/ml (upper quartile, n=40 patients) had a median survival of 27 months, while median survival of all other patients was 98 months (p=0.031). In conclusion, our study provided evidence that sclerostin is increased in the serum of patients with MM and correlates with advanced ISS stage, increased bone resorption, reduced osteoblast function and poor survival. SPARC is reduced in MM possibly confirming the reduced osteoblast function observed in these patients. Sclerostin seems to participate in the biology of MM and thus it may be a possible target for the development of novel therapies that can both increase osteoblast function and target myeloma cells.
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| 15. |
- van Santen, Victor J. B., et al.
(författare)
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Compressed Prostate Cancer Cells Decrease Osteoclast Activity While Enhancing Osteoblast Activity In Vitro
- 2023
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Once prostate cancer cells metastasize to bone, they perceive approximately 2 kPa compression. We hypothesize that 2 kPa compression stimulates the epithelial-to-mesenchymal transition (EMT) of prostate cancer cells and alters their production of paracrine signals to affect osteoclast and osteoblast behavior. Human DU145 prostate cancer cells were subjected to 2 kPa compression for 2 days. Compression decreased expression of 2 epithelial genes, 5 out of 13 mesenchymal genes, and increased 2 mesenchymal genes by DU145 cells, as quantified by qPCR. Conditioned medium (CM) of DU145 cells was added to human monocytes that were stimulated to differentiate into osteoclasts for 21 days. CM from compressed DU145 cells decreased osteoclast resorptive activity by 38% but did not affect osteoclast size and number compared to CM from non-compressed cells. CM was also added to human adipose stromal cells, grown in osteogenic medium. CM of compressed DU145 cells increased bone nodule production (Alizarin Red) by osteoblasts from four out of six donors. Compression did not affect IL6 or TNF-alpha production by PC DU145 cells. Our data suggest that compression affects EMT-related gene expression in DU145 cells, and alters their production of paracrine signals to decrease osteoclast resorptive activity while increasing mineralization by osteoblasts is donor dependent. This observation gives further insight in the altered behavior of PC cells upon mechanical stimuli, which could provide novel leads for therapies, preventing bone metastases.
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| 16. |
- Voskaridou, Ersi, et al.
(författare)
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High Circulating Levels of Sclerostin Correlate with Bone Mineral Density In Patients with Thalassemia and Osteoporosis: The Role of the Wnt Signaling In the Pathogenesis of Bone Loss In Thalassemia
- 2010
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 116:21, s. 1010-1010
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Tidskriftsartikel (refereegranskat)abstract
- Abstract 1010Osteoporosis represents an important cause of morbidity in adult patients with thalassemia. Osteoclast activity is elevated in thalassemia-induced osteoporosis, and thus bisphosphonates have been used for its management. Moreover, osteoblasts are also deregulated in thalassemia patients but there is very limited data for the underlying mechanisms of this deregulation. Osteocyte seems to be a key cell for the control of bone remodeling. Sclerostin is a secreted inhibitor of the wingless-type and integrase 1 (Wnt) canonical pathway which is produced by osteocytes and has inhibitory effects on bone formation by preventing the activation of lining cells as well as by inhibiting the function of active osteoblasts. The aim of this study was to evaluate, for the first time, the circulating levels of sclerostin in patients with thalassemia and osteoporosis who received therapy with zoledronic acid (ZOL) and explore possible correlations with clinical and laboratory data in an attempt to clarify if there is any role of sclerostin in the pathogenesis of bone loss in thalassemia. Sixty-six patients (22M/44F, median age 42 years) with thalassemia-induced osteoporosis who participated in a phase 2, randomized, placebo-controlled trial, which was previously published, were studied. In summary, patients were blindly randomized to receive ZOL at a dose of 4 mg, iv, in 15 min infusion, every 6 months (group A, n=23) or every 3 months (group B, n=21), or to receive placebo every 3 months (group C, n=22) for a 12-month period (Voskaridou et al, Hametologica 2006;91:1193-202). Bone mineral density (BMD) of the lumbar spine (L1-L4), femoral neck (FN) and distal radius (R) was determined using Dual-energy X-ray Absorptiometry before and 12 months post-ZOL treatment. Circulating sclerostin was measured in the serum of all patients at baseline and after 12 months of therapy, using an ELISA methodology developed by BDF for Biomedica Medizinprodukte (Vienna, Austria), along with a series of serum bone indices: i) bone resorption markers [C-terminal telopeptide of collagen type-1 (CTX) and tartrate resistant-acid phosphatase (TRACP-5b)]; ii) bone formation markers [bone-alkaline phosphatase (bALP), osteocalcin and C-terminal propeptide of collagen type-I (CICP)]; iii) osteoclast regulators [RANKL, osteoprotegerin (OPG) and osteopontin] and iv) dickkopf-1 (Dkk-1), which is another inhibitor of Wnt signaling, as previously described (Voskaridou et al, Haematologica 2009;94:725-8). The above bone markers were also evaluated in 30, age- and gender-matched, healthy controls (11M/19F, median age 44 years), while sclerostin was also measured in 62 women with post-menopausal osteoporosis (median age 63 years). At baseline, patients with thalassemia and osteoporosis had elevated circulating levels of sclerostin (median: 605 pg/mL, range: 22–1227 pg/mL) compared to healthy controls (250 pg/mL, 0–720 pg/mL, p<0.001) and reduced levels of sclerostin compared with postmenopausal women with osteoporosis (840 pg/mL, 181–1704 pg/mL, p<0.001). Patients with thalassemia had also increased values of CTX (p<0.001), Dkk-1 (p<0.001), bALP (p<0.001), CICP (p=0.003), TRACP-5b (p<0.01), and sRANKL/OPG ratio (p=0.001). Sclerostin levels correlated with BMD in all studied sites L1-L4 (r=0.454, p<0.001), R (r=0.324, p=0.01) and FN (r=0.268, p=0.035). Similar results were obtained for post-menopausal women with osteoporosis for L1-L4 BMD (r=0.501, p<0.001). The other Wnt inhibitor, Dkk-1 also correlated with BMD of L1-L4 (r=-0.290, p=0.022) and R (r=-0.415, p=0.001). Patients who received ZOL did not alter their sclerostin levels after 12 months of therapy, but reduced their circulating Dkk-1 (from 39.6±16.6 to 28.9±16.3 pmol/L, p=0.004). In contrast, placebo group patients showed an increase of sclerostin levels (p=0.01) and a borderline increase of Dkk-1 (p=0.08). In conclusion, the results of this study show that circulating sclerostin is elevated in thalassemia patients with osteoporosis and correlated with their BMD. Furthermore, the high Dkk-1 serum levels and their association with BMD observed in these patients support the notion of a disrupted Wnt signaling in patients with thalassemia and osteoporosis which leads, in turn, to osteoblast deregulation. These findings give the rationale for the use of novel drugs targeting sclerostin and Dkk-1 in patients with thalassemia-induced osteoporosis.
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| 17. |
- Voskaridou, E., et al.
(författare)
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High Circulating Sclerostin is Present in Patients with Thalassemia-associated Osteoporosis and Correlates with Bone Mineral Density
- 2012
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 44:12, s. 909-913
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Tidskriftsartikel (refereegranskat)abstract
- Osteoporosis is a severe complication of thalassemia. Sclerostin is a Wnt signaling inhibitor, which is produced by osteocytes and inhibits osteoblast function. Sclerostin is implicated in the pathogenesis of osteoporosis of different etiology. The aim of the study was to evaluate circulating sclerostin in 66 patients (median age 42 years) with thalassemia and osteoporosis who participated in a phase 2, randomized study (zoledronic acid vs. placebo) and the results were compared with those of 30 healthy controls (median age 44 years) without osteopenia/osteoporosis and 62 women with postmenopausal osteoporosis (median age 63 years). At baseline, thalassemic patients with osteoporosis had elevated circulating levels of sclerostin (median: 605 pg/ml, range: 22-1,227 pg/ml) compared to healthy controls without osteopenia/osteoporosis (250 pg/ml, 0-720 pg/ml, p<0.001) and reduced levels of sclerostin compared with postmenopausal women with osteoporosis (840 pg/ml, 181-1,704 pg/ml, p<0.001). Thalassemia patients had also increased serum dickkopf-1 (Dkk-1) and high bone turnover. Circulating sclerostin levels correlated with bone mineral density in lumbar spine (r=0.619, p<0.001), distal radius (r=0.401, p=0.001) and femoral neck (r=0.301, p=0.021). Zoledronic acid did not alter sclerostin levels after 12 months of therapy, although it reduced circulating Dkk-1. We conclude that circulating sclerostin is elevated in thalassemia patients with osteoporosis and correlated with their BMD, but it was not reduced post zoledronic acid administration. These findings suggest that high sclerostin may serve as a marker of increased osteocyte activity in thalassemia patients. Drugs targeting sclerostin may also be used in this difficult to treat disorder associated with bone loss.
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