Urinary deoxypyridinoline excretion for the evaluation of bone turnover in chronic renal failure.
BACKGROUND
The urinary excretion of deoxypyridinoline (DPD) was evaluated in predialysis chronic renal failure (CRF), together with intact PTH and several classic markers of bone turnover in order to assess whether urine free and total DPD excretion are equivalent parameters of bone turnover in CRF, and to evaluate the relationship between urine DPD excretion, PTH and the other bone markers.


METHODS
The study was carried out in 94 patients with different degrees of renal failure due to various kidney diseases. Besides urinary DPD expressed as free DPD, total DPD, free/total DPD, free DPD/Cr and total DPD/Cr, the following determinations were made: intact PTH, bone alkaline phosphatase (BALP), total alkaline phosphatase (AP), osteocalcin (BGP), serum C-terminal telopeptide of collagen type I (ICTP) and hydroxyproline (OHpro). The patients were divided into 3 groups according to the increasing severity of renal failure (Ccr >40, 40-20, <20 ml/min).


RESULTS
The ratio free/total DPD decreased (NS) with advancing renal failure, and was inversely correlated with total DPD excretion. While PTH increased progressively to about four times the values observed in the Ccr >40 group, there was a parallel increase only in BGP and ICTP, parameters retained in the serum with decreasing renal function, while AP, BALP, total DPD and OHpro did not change. However, significant correlations between total DPD/Cr and PTH, BALP, BGP and ICTP were also found.


CONCLUSIONS
In CRF free DPD is an unreliable index of bone turnover due to a probable interference in its production from the peptide-bound DPD. Total DPD or total DPD/Cr are better used. In spite of the significant correlations observed in advanced renal failure between PTH and most of the parameters examined, a resistance of bone tissue to PTH action in CRF must be considered.
Coen
G
G
Renal Pathophysiology and Hypertension Unit, Institute of 2nd Medical Clinics, La Sapienza University, Rome, Italy. coen.gf@flashnet.it
Mantella
D
D
Calabria
S
S
Sardella
D
D
Manni
M
M
Fassino
V
V
D'Anello
E
E
Giustini
M
M
Taggi
F
F
D000368:Aged; D000469:Alkaline Phosphatase / Q000378:metabolism; D000596:Amino Acids / Q000652:urine*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D016723:Bone Remodeling; D001842:Bone and Bones / Q000201:enzymology; D003094:Collagen; D024042:Collagen Type I; D003404:Creatinine / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D006909:Hydroxyproline / Q000652:urine; D007676:Kidney Failure, Chronic / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D010455:Peptides
D000596:Amino Acids; D015415:Biomarkers; D024042:Collagen Type I; D010281:Parathyroid Hormone; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; C036020:deoxypyridinoline; D003094:Collagen; D003404:Creatinine; D000469:Alkaline Phosphatase; D006909:Hydroxyproline