Avaliação de biomarcadores relacionados ao metabolismo mineral e ósseo em pacientes adultos transplantados renais: relação com polimorfismos XbaI e PvuII do gene ESR1

Abstract

The mineral and bone disorder of chronic kidney disease (CKD-MBD) is characterized by a clinical condition which encompasses mineral, bone and cardiovascular abnormalities resulting from complications of chronic kidney disease, which may remain even after renal transplantation. The protective effect of estrogen on kidney and mineral and bone metabolism has been demonstrated, as well as the association of estrogen receptor 1 (ESR1) gene polymorphism with outcomes related to CKD-MBD, so it is opportune to evaluate them in the post - renal transplantation. The objective of this study was to evaluate the levels of calcium, phosphorus, parathyroid hormone (PTH) and 25-hydroxy-vitamin D in renal transplant recipients and to correlate them with renal function markers and the XbaI (rs9340799) and PvuII (rs2234693) polymorphisms of the ESR1 gene. The cohort was composed of 164 renal transplant recipients, for which the biomarkers of mineral and bone metabolism and the XbaI and PvuII polymorphisms were determined. For the analyzes, subjects were categorized according to serum creatinine levels, estimated glomerular filtration rate, post-transplant time, PTH and vitamin D levels. It was observed that higher concentrations of PTH were associated with a higher serum creatinine level and a lower estimated glomerular filtration rate. The worse renal function, evaluated by the estimated glomerular filtration rate, was also related to higher serum levels of phosphorus. Higher calcium concentrations were found among individuals with shorter time after transplantation. PTH varied significantly according to genetic evaluations, with the CC genotype of the PvuII polymorphism being found more frequently among individuals with lower levels of the hormone. XbaI polymorphism did not influence the concentrations of any of the biomarkers. The persistence of elevated levels of PTH in the post-renal transplantation was the most relevant finding and, despite the variations observed for the other biomarkers, renal transplant recipients in this study appeared are under adequate control of the variations of the mineral and bone metabolism which they are submitted to.