Kidney

Biography

Biography: Beata Znorko

Abstract

Chronic kidney disease-mineral and bone disorders (CKD-MBD) are common during the course of CKD and related to disturbances in bone strength and metabolism. Recent research shows that the osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL) play a significant role in the development of CKD-MBD. The aim of the study was to investigate if the OPG/RANKL system affects biomechanical properties in young, growing rats with experimental model of chronic renal failure (CRF). The animals were divided into two groups: sham-operated and subtotal nephrectomized rats. Left femurs were excised one and three months after nephrectomy for determination of biomechanical properties: three-point-bending test in femoral diaphysis and bending test in femoral neck. Soluble RANKL(sRANKL) and OPG were measured in homogenates from trabecular and cortical bone tissue. Trabecular and cortical OPG was increased in CRF in comparison to control three months after surgery, whereas trabecular sRANKL was increased one month after nephrectomy. At the level of femoral neck, OPG in trabecular bone tissue
correlated positively with stiffness (r=0.539,p=0.017) and ultimate load (Fu) (r=0.611,p=0.05), and inversely with work to fracture (W) (r=-0.465,p=0.044). sRANKL in both and cortical bone tissue was positively correlated with W (r=0.648,p=0.01; r=0.420;p=0.05, respectively) and inversely with stiffness (r=0,474,p=0.026). At the level offemoral diaphysis, sRANKL was inversely associated with Fu  (r=-0.503,p=0.017) and there were no associations between cortical OPG levels and these parameters in both femoral neck and diaphysis. In young, rapidly growing rats OPG and sRANKL exerts opposite effect on biomechanical bone strength in experimental CRF.