ABSTRACT
Introduction:
Normal renal function is a prerequisite for maintaining the normal balance of calcium and phosphorus. The incidence of 1,25-dihydroxyvitamin D (1,25(OH)2D, or calcitriol) deficiency in renal transplant patients is 50%. The causes are multifactorial, including low availability of 25-hydroxyvitamin D (25(OH)D). Although kidney transplant is the treatment of choice, some patients maintain bone changes resulting from the interplay of several factors, such as persistence of mineral disorders due to graft dysfunction and effect of immunosuppressive drugs.
Objective:
To evaluate the dynamics of some biochemical parameters after kidney transplant.
Material and methods:
Thirteen patients followed from pre-transplant to three months post-transplant, with measurements of creatinine, calcium, phosphate, parathyroid hormone (PTH), 25(OH)D, and calcitriol.
Results:
Normalization of calcium was observed in 10 of the 13 patients (77%), and only one did not have phosphate levels reduced after transplant; all patients presented elevated PTH in pre-transplant, four of which (31%) maintained this change; nine of the 13 patients (69%) had low levels of 25(OH)D, which remained essentially unchanged after transplantation. Low pre-transplant levels of calcitriol were observed in 46% of the patients, and remained in only one. This patient had a very low pre-transplant level of 25(OH)D (8 ng/ml) that did not change after surgery. A possible explanation for this is the reduced substrate availability for 1-alpha-hydroxylase.
Conclusion:
Our data, in agreement with the literature, confirm that even patients with good outcomes after renal transplantation can still present important biochemical changes associated with deterioration of bone quality.
Key words:
renal transplantation; 25-hydroxyvitamin D; calcitriol; bone metabolism