Evaluation of Serum β-Carboxy-Terminal Cross-Linking Telopeptide of Type I Collagen as Marker of Bone Resorption in Chronic Hemodialysis Patients

Abstract

Background: The carboxy-terminal cross-linking telopeptide of type I collagen (β-CrossLaps, β-CTX) is released into the circulation during degradation of type I collagen and serves as a marker of bone resorption. β-CTX is known to undergo a diurnal rhythm in normal individuals and to accumulate in chronic renal failure. β-CTX has a potential role in noninvasive diagnosis of renal bone disease. Methods: Serum β-CTX was compared to parathyroid hormone (PTH) and other biochemical bone markers in 90 unselected hemodialysis patients. Results: Mean β-CTX was elevated above the normal range (1.72 ± 0.93 µg/l); there were large individual variations. Serum β-CTX was significantly correlated with various PTH assays (r >0.56) and with tartrate-resistant acid phosphatase 5b (TRACP 5b, r = 0.629), bone-specific alkaline phosphatase (r = 0.404) and osteocalcin (r = 0.534, all correlations p < 0.001). The correlation between β-CTX and PTH was significantly higher than the correlation between TRACP 5b and PTH. Several factors which could confound interpretation of serum β-CTX were assessed in further studies: (i) There was no recognizable influence of the time of blood sampling (morning dialysis shift versus afternoon dialysis shift) on serum β-CTX. (ii) Serum β-CTX was not significantly related to residual diuresis of patients. Conclusions: We found a high association between β-CTX and other established markers of bone and calcium metabolism demonstrating the potential utility of β-CTX as marker of bone resorption in renal bone disease. However, further studies employing bone histology are still warranted to exactly define the influence of glomerular retention on serum β-CTX in end-stage renal disease.

Correlations and time course of FGF23 and markers of bone metabolism in maintenance hemodialysis patients

“…However, there is limited data on circadian rhythmicity in hemodialysis patients with conflicting results [14,15]. In our study, timing of dialysis was not significantly different between both dialysate calcium groups.…”

Severe secondary hyperparathyroidism in patients on haemodialysis is associated with a high initial serum parathyroid hormone and beta-CrossLaps level: Results from an incident cohort

“…A high baseline PTH level may reflect the limited quality of predialysis care, including inadequate biological targets and/or the medical strategy that was used. The high baseline CTX level is more questionable since the impact of renal function has been previously reported [ 22 ]. It is hypothesized that the renal elimination of CTX is low in CKD stage 5 before dialysis and does not significantly affect its serum level.…”

Variations of parathyroid hormone and bone biomarkers are concordant only after a long term follow-up in hemodialyzed patients

“…Variations of P1NP and b-ALP over time seem particularly concordant. Moreover, concentrations of these two biomarkers (at least the intact form of P1NP) are not influenced by CKD status 8 , 22 , contrary to CTX 3 , 8 , 23 , 24 . The choice of one biomarker could be dependent on the availability of the biomarker in the laboratory and/or some specific characteristics of the patients (for instance, it has been suggested that severe hepatic dysfunction could interfere with b-ALP measurement) 8 , 25 .…”