Avaliação de marcadores de metabolismo ósseo nem pacientes transplantados renais

Abstract

Introduction: Mineral and Bone Disorder (MBD) after kidney transplantation is influenced by immunosuppressive therapies, pre-existing renal osteodystrophy, de novo hyperparathyroidism and traditional risk factors of fractures, osteoporosis and osteopenia. In chronic kidney disease (CKD), the uremic and inflammatory environment and the increased product of calcium and phosphorus predispose to extraosseous calcifications such as vascular calcification. There is an imbalance between the inhibiting and inducing factors of calcification. After kidney transplantation, little is known about the effect on bone metabolism markers. This study aimed to measure the serum concentrations of bone metabolism molecules in kidney transplant patients and to compare with levels found in patients on hemodialysis and healthy individuals. Methods: This is a cross-sectional study with three groups: kidney transplantation patients, patients on hemodialysis, and healthy controls. The plasma concentrations of Dickkopf -related protein 1 (DKK1), osteoprotegerin (OPG), osteocalcin (OC), osteopontin (OPN), sclerostin (SOST), and fibroblast growth factor 23 (FGF-23) were measured in these three groups. The associations between the measurements of these molecules with clinical, demographic and laboratory variables (calcium, phosphorous, 25 OH vitamin D, alkaline phosphatase, PTH and creatinine) were evaluated. Results: A total of 114 patients were included in the study. Transplant recipients showed significantly lower levels of DKK1 (p < 0.001) OPG (p < 0.001), OC (p < 0.001), OPN (p = 0.001), OST (p < 0.001), and FGF-23 (p < 0.001) when compared to patients on hemodialysis. In comparison to healthy controls, transplant recipients also presented lower levels of DKK1 (p = 0.019), OPG (p < 0.001), OC (p = 0.027), SOST (p < 0.001) and FGF-23 (p = 0.043). Regarding demographic data, women presented lower serum SOST levels when compared to men in the hemodialysis group (p = 0.012). No other significant associations were found between levels of molecules and baseline demographic and clinical data. Conclusion: Our findings showed a reduction in bone metabolism markers, DKK1, OPG, OC, OPN and SOST, after kidney transplantation. The first years after kidney transplantation modulate MBD markers, suggesting a significant improvement in relation to end-stage kidney disease.