Serum osteoprotegerin as a determinant of bone metabolism in a longitudinal study of human pregnancy and lactation.
Osteoprotegerin (OPG) is a soluble decoy receptor that inhibits bone resorption by binding to receptor activator of nuclear factor kappa B ligand. Murine studies suggest that OPG is elevated in pregnancy, but its role in human pregnancy is unknown. We evaluated the relationship among OPG, bone turnover, and bone density in a longitudinal study of planned human pregnancy and lactation (n = 17; age, 20-36 yr). Samples were collected before conception; at 16, 26, and 36 wk gestation; and at 2 and 12 wk postpartum. Indexes of bone resorption included serum beta C-terminal and urinary N-terminal (uNTX) telopeptides of type I collagen. OPG increased by 110 +/- 16% (mean +/- SEM) at 36 wk (P < 0.001), followed by a rapid postpartum decline in both lactating and nonlactating women. Bone resorption was elevated at 36 wk (serum beta C-terminal telopeptides by 76 +/- 17%; urinary N-terminal telopeptides by 219 +/- 41%; P < 0.001). The tissue source of OPG in pregnancy is unknown. Human breast milk contains large amounts of OPG (162 +/- 58 ng/ml in milk vs. 0.42 +/- 0.03 ng/ml in nonpregnant serum). However, the rapid postpartum decline in serum OPG and the low serum OPG in neonates suggest a placental source. There was no correlation between change in OPG and bone turnover or bone mineral density (P > 0.05), and the physiological importance of elevated OPG in human pregnancy remains uncertain.
Naylor
K E
KE
Bone Metabolism Group, University of Sheffield, Sheffield, United Kingdom S5 7AU.
Rogers
A
A
Fraser
R B
RB
Hall
V
V
Eastell
R
R
Blumsohn
A
A
D000328:Adult; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D004967:Estrogens / Q000097:blood; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007231:Infant, Newborn; D007774:Lactation / Q000502:physiology*; D008137:Longitudinal Studies; D008562:Membrane Glycoproteins / Q000378:metabolism; D053244:Osteoprotegerin; D049590:Postpartum Period / Q000378:metabolism; D011247:Pregnancy / Q000378:metabolism*; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000097:blood*; D018124:Receptors, Tumor Necrosis Factor
D002352:Carrier Proteins; D004967:Estrogens; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human