Can we use circulating biomarkers to monitor bone turnover in CKD haemodialysis patients? Hypotheses and facts.

Assessing bone turnover is a key diagnostic tool in the global management of chronic kidney disease-mineral and bone disorder (CKD-MBD). Since bone biopsy is invasive and cannot be repeated in clinical practice and because bone histomorphometry is less available due to the lack of specialized laboratories, we will focus on potential biomarkers used to assess and monitor bone turnover. After briefly reviewing the pathophysiology of bone turnover in CKD and haemodialysis patients, we will focus on the strengths and limitations of the now recommended biomarkers, i.e. parathormone and bone-specific alkaline phosphatase. We will consider the clinical and also the biological aspects of the topic and also insist on the use of these biomarkers for the monitoring, and the follow-up of the turnover in haemodialysis subjects. Finally, we will discuss some of the most promising, but still not recommended, emerging biomarkers.