Serum concentrations of carboxyterminal cross-linked telopeptide of type I collagen (ICTP), serum tartrate resistant acid phosphatase, and serum levels of intact parathyroid hormone in parathyroid hyperfunction

Abstract

De la Piedra C, Díaz Martín M A, Díaz Diego E M, López Gavilanes E, González Parra E, Caramelo C, Rapado A. Serum concentrations of carboxyterminal cross-linked telopeptide of type I collagen (ICTP), serum tartrate resistant acid phosphatase, and serum levels of intact parathyroid hormone in parathyroid hyperfunction. Scand J Clin Lab Invest 1994; 54: 11-15.

We have studied the levels of a new biochemical marker of bone resorption, carboxyterminal cross-linked telopeptide of type I collagen (ICTP), in 26 healthy control subjects, 15 patients with primary hyperparathyroidism (PHPT) and 17 patients with secondary hyperparathyroidism (secondary HPT). Levels of ICTP in PHPT and secondary HPT have been correlated with those of serum tartrate resistant acid phosphatase (TRAP), another biochemical marker of bone turnover, and with serum levels of intact parathyroid hormone (iPTH). The ICTP levels of the control group were 2.07 ± 0.58 μgl⁻¹ n = 26, range 1.3-3.2. They were independent of sex and age in the studied age range (30-62 years). The ICTP levels of PHPT patients were 3.5 ± 3.5μgl⁻¹ mean ± SD, range 0.5-12.2μgl⁻¹, significantly higher than those of control subjects (p < 0.05). We found a significant linear correlation between values of ICTP and iPTH levels (p < 0.01), between values of ICTP and serum activity of TRAP (p < 0.01) and between iPTH and TRAP levels (p < 0.01) in patients with PHPT. The ICTP levels in patients with secondary HPT were higher than those of patients with PHPT, 46±37μgl⁻¹ range 12-167μgl⁻¹ (p < 0.001) due to the impaired renal clearance of this peptide. We did not find a significant linear correlation between values of ICTP and iPTH levels in the serum of patients with secondary HPT, although we found a significant correlation between levels of ICTP and levels of TRAP, both biochemical markers of bone turnover. The above results indicate that the new biochemical marker of bone turnover, serum ICTP, could be used as an index of bone resorption in states of parathyroid hyperfunction, if renal function is maintained.

Key Words:

• parathyroid hormone
• tartrate-resistant acid phosphatase
• telo-peptide