Background: Secondary hyperparathyroidism is an important factor of chronic kidney disease-mineral and bone disorder (CKD-MBD), which frequently results in maintenance dialysis patients having super-high levels of serum intact-parathyroid hormone (iPTH) and bone turnover markers (BTMs). This study aimed to investigate the immediate changes of iPTH and BTMs levels after renal transplantation during the perioperative period, and to explore the allograft function rapid recovery and the effect of high-dose glucocorticoids on serum iPTH and BTMs.
Methods: Between April 2018 and August 2021, a total of 346 Chinese kidney transplantation (KT) recipients (median age, 34.0 years; 236 males and 110 females; median dialysis duration, 12 months) were enrolled in this retrospective cohort study. The included patients had been undergoing maintenance dialysis for at least three months before transplant, and all of them accepted short-term high-dose methylprednisolone (MP) to prevent allograft rejection in the perioperative period. Allograft functions were evaluated and divided into different groups accorded to the CKD staging on the postoperative fifth day. Serum beta C-terminal crosslinking telopeptide of type I collagen (��-CTX), type 1N-terminal propeptide (P1NP), osteocalcin (OC), and iPTH were measured from fasting morning blood samples before surgery and on the postoperative fifth day with an electro-chemiluminescence immunoassay analyzer (2012; Roche Diagnostics).
Results: Among the participants, the graft functions were in CKD-II (n=134), CKD-III (n=137), CKD-IV (n=24), and CKD-V (n=51) after the postoperative fifth day. The changes of P1NP level [-95.8 (-84.0 to -2.4) ng/mL] and the OC level [-88.0 (-96.9 to -42.9) ng/mL] were significantly greater than those of the ��-CTX level [-62.3 (-73.6 to 0) pg/mL] and the iPTH level [-57.6 (-15.6 to 11.9) pg/mL] (P<0.001). In the CKD-V group, the changes of ��-CTX level [-0.7 (-43.15 to 0) pg/mL (+15.7%, P=0.61)] and the iPTH level [-8.69 (226.73 to 17.79) pg/mL (-22.8%), P=0.36] were less than those of the CKD-II group (P<0.001). ��-CTX, P1NP, and OC levels related with iPTH (r=0.413, 0.459, 0.482, respectively, P<0.001), and iPTH level with estimated glomerular filtration rate (eGFR; r=-0.474, P<0.001).
Conclusions: The super-high levels of BTMs and iPTH rapidly descended with recuperating allograft function during the short-term, indicating that improvement of current dialysis equipment to achieve clean up iPTH could more favorably decrease BMTs and improve CKD-MBD. Osteogenesis markers P1NP and OC still decreased and were not affected in CKD-V group, indicating that high-dose glucocorticoids might strongly inhibit osteoblast activity.
