Bone resorption in kidney transplant recipients

Area of Science:

• Nephrology
• Endocrinology
• Bone Metabolism

Background:

• Persistent hyperparathyroidism (HP) after kidney transplantation can worsen bone disease and damage the graft.
• Early diagnosis is crucial for timely intervention.

Purpose of the Study:

• To evaluate the utility of urinary collagen cross-links (PYD and DPD) in detecting bone resorption in stable kidney transplant recipients.
• To assess the correlation of these markers with established hyperparathyroidism indicators.

Main Methods:

• Seventy stable kidney transplant recipients were studied between 1997 and 2006.
• Urinary PYD and DPD levels were measured and correlated with intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), osteocalcin (OC), creatinine, and age.
• Statistical analyses included correlation matrix and stepwise regression.

Main Results:

• All patients exhibited elevated urinary cross-links despite normal calcemia and phosphoremia.
• Significant correlations were found between PYD and ALP, PYD and DPD, pre- and posttransplant iPTH, and creatinine and ALP.
• Specific correlations varied between immunosuppressive protocol groups, with age correlating with posttransplant iPTH in one group.

Conclusions:

• Urinary collagen cross-links (PYD and DPD) can identify bone resorption in kidney transplant recipients.
• These markers are valuable for early diagnosis of hyperparathyroidism when conventional bone metabolism parameters are inconclusive.