Sustained elevation of parathyroid hormone (PTH) is catabolic to cortical bone, as evidenced by deterioration in bone structure (cortical porosity), and is a major factor for increased fracture risk in chronic kidney disease (CKD). Etelcalcetide (AMG 416), a novel peptide agonist of the calcium-sensing receptor, reduces PTH levels in subtotal nephrectomized (Nx) rats and in hemodialysis patients with secondary hyperparathyroidism (SHPT) in clinical studies; however, effects of etelcalcetide on bone have not been determined. In a rat model of established SHPT with renal osteodystrophy, etelcalcetide or vehicle was administered by subcutaneous (s.c.) injection to subtotal Nx rats with elevated PTH (>750pg/mL) once per day for 6weeks. Sham-operated rats receiving vehicle (s.c.) served as non-SHPT controls. Prior to treatment, significant increases in serum creatinine (2-fold), blood urea nitrogen (BUN, 3-fold), PTH (5-fold), fibroblast growth factor-23 (FGF23; 13-fold) and osteocalcin (12-fold) were observed in SHPT rats compared to non-SHPT controls. Elevations in serum creatinine and BUN were unaffected by treatment with vehicle or etelcalcetide. In contrast, etelcalcetide significantly decreased PTH, FGF23 and osteocalcin, whereas vehicle treatment did not. Cortical bone porosity increased and bone strength decreased in vehicle-treated SHPT rats compared to non-SHPT controls. Cortical bone structure improved and energy to failure was significantly greater in SHPT rats treated with etelcalcetide compared to vehicle. Mineralization lag time and marrow fibrosis were significantly reduced by etelcalcetide. In conclusion, etelcalcetide reduced bone turnover, attenuated mineralization defect and marrow fibrosis, and preserved cortical bone structure and bone strength by lowering PTH in subtotal Nx rats with established SHPT.
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http://dx.doi.org/10.1016/j.bone.2017.08.026 | DOI Listing |
J Biomech Eng
January 2025
Dr. Carl D. and H. Jane Clay Department of Mechanical Engineering, Ohio Northern University, 525 S. Main St, Ada OH 45810.
Evaluating the contribution of microstructure to overall bone strength is tricky since it is difficult to control changes to pore structure in human or animal samples. We developed an open-source program that can generate three-dimensional models of micron-scale cortical bone. These models can be highly customized with a wide array of variable input parameters to allow for generation of samples with high similarity to CT scans of cortical bone or with specific geometric features.
View Article and Find Full Text PDFCalcif Tissue Int
January 2025
Neuromuscular Research Laboratory/Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, 3860 S. Water St, Pittsburgh, PA, 15203, USA.
Military training improves tibial density, structure, and estimated strength; however, men and women may adapt differently. Most work performed in military populations has assessed changes in bone health during initial entry programs, a timeframe at the beginning of a service member's career when bones may be more adaptable to a novel mechanical stimulus. The purpose of this investigation was to examine changes in tibial volumetric bone mineral density (vBMD), structure, and estimated strength, and biomarkers of bone metabolism (P1NP, osteocalcin, TRAP5b, sclerostin) between male and female candidates measured at the start and end of United States Marine Corps Officer Candidates School (OCS), a 10-week military training program attended by older service members (~ 25 y/o) who may have previous military experience.
View Article and Find Full Text PDFCalcif Tissue Int
January 2025
Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport, University of Porto, (FADEUP), Rua Dr. Plácido Costa 91, 4200-450, Porto, Portugal.
Swimming is a popular sport with several health benefits, but its effects on bone quality are controversial possibly due to distinct effects on different anatomical regions. Our aim was to investigate the effect of 8-month swimming on bone growth, mass, geometry, trabecular microarchitecture and osteocyte density of the lumbar vertebrae, femur and tibia of male rats. Wistar rat models were assigned to either a swimming (n = 10; 2h/d, 5 d/week) or a physically active control group (n = 10) for 8 months, after which they were sacrificed and their lumbar vertebrae, femur and tibia assessed for bone mass, cortical geometry, trabecular microarchitecture and osteocyte density through µ-CT and histology.
View Article and Find Full Text PDFProc Inst Mech Eng H
January 2025
Department of Mechanical Engineering, Chandigarh University, Mohali, Punjab, India.
Bone is a highly heterogeneous and anisotropic material with a hierarchical structure. The effect of diaphysis locations and directions of loading on elastic-plastic compressive properties of bovine femoral cortical bone was examined in this study. The impact of location and loading directions on elastic-plastic compressive properties of cortical bone was found to be statistically insignificant in this study.
View Article and Find Full Text PDFBackground: Comorbidities are becoming increasingly evident during various Alzheimer's disease related pathologies. It was found that patients with AD have a higher risk for fractures and falls. Further people who have an incident of falls/fractures have a higher risk for cognitive decline.
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