Changes in markers of bone metabolism during dexamethasone treatment for chronic lung disease in preterm infants.
OBJECTIVE
To characterise the change in serum and urinary bone markers in the early postnatal period, and to assess the effect of systemic corticosteroid on bone metabolism in preterm infants.


METHODS
Bone formation was quantified by measurement of serum concentrations of bone specific alkaline phosphatase (BALP) and osteocalcin. Bone resorption was measured by monitoring creatinine adjusted urinary deoxypyridinoline (Dpd) concentration. Blood and urinary samples were collected from corticosteroid treated infants (n = 19) immediately before the start (T(d-pre)), three weeks after the start (T(d-end)), and two (T(d-post2)) and four weeks (T(d-post4)) after the end of the dexamethasone course. Untreated patients (n = 30) had specimens taken at week 3 (T(wk-3)), 6 (T(wk-6)), 8 (T(wk-8)), and 10 (T(wk-10)) of postnatal age.


RESULTS
Serum concentrations of BALP and osteocalcin at T(d-end) were significantly lower than pretreatment levels and the levels at the corresponding time point (T(wk-6)) of the non-treatment group. In contrast, urinary Dpd concentration at T(d-end) was not significantly decreased compared with the pretreatment level. However, it was significantly lower than the urinary Dpd concentration at T(wk-6) of the non-treatment group. The rate of increase in lower leg length was significantly higher in the non-treatment group between weeks 3 and 6 than in the corresponding period during dexamethasone treatment in the corticosteroid group.


CONCLUSIONS
Systemic corticosteroid causes appreciable suppression of serum BALP and osteocalcin and, to a lesser extent, urinary Dpd. The results suggest that corticosteroid inhibits bone growth mainly by decreasing bone formation.
Ng
P C
PC
Department of Paediatrics, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong. pakcheungng@cuhk.edu.hk
Lam
C W K
CW
Wong
G W K
GW
Lee
C H
CH
Cheng
P S
PS
Fok
T F
TF
Chan
I H S
IH
Wong
E
E
Cheung
K
K
Lee
S Y
SY
D000469:Alkaline Phosphatase / Q000097:blood; D000596:Amino Acids / Q000652:urine; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D015415:Biomarkers / Q000032:analysis; D001846:Bone Development / Q000187:drug effects*; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000378:metabolism / Q000503:physiopathology*; D019102:Infant, Very Low Birth Weight; D008171:Lung Diseases / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D015675:Osteocalcin / Q000097:blood; D011446:Prospective Studies
D000596:Amino Acids; D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D005938:Glucocorticoids; D015675:Osteocalcin; D003907:Dexamethasone; C036020:deoxypyridinoline; D000469:Alkaline Phosphatase