Determining the source of fetal adiponectin.

OBJECTIVE: To determine whether maternal, placental or fetal compartment contributes to the high levels of cord blood adiponectin. STUDY DESIGN: Serum adiponectin levels were compared from 62 newborns and their mothers as well as 32 newborns at delivery and 4 days postpartum. In addition, human placental tissues were tested for the presence of adiponectin mRNA by reverse transcriptase polymerase chain reaction. RESULTS: Cord blood serum adiponectin levels were significantly higher and did not correlate with maternal adiponectin levels (32.5 +/- 7.5 vs. 11.0 +/- 3.6 microg/mL, p < 0.001). Cord blood and day 4 serum adiponectin did not differ significantly (32.6 +/- 7.6 vs. 29.5 +/- 8.4 microg/mL, p < 0.3). In addition, adiponectin mRNA was not expressed in the placenta. CONCLUSION: These findings preclude the possibility of a placental or maternal origin of cord adiponectin. Thus, the high cord adiponectin levels may be attributed to fetal tissues.

Adiponectin in human cord blood: relation to fetal birth weight and gender.

Adiponectin is an adipocyte-derived plasma protein with insulin-sensitizing and antiatherosclerotic properties. The aim of this study was to examine whether adiponectin is present in human fetal blood, to define its association with fetal birth weight, and to evaluate whether dynamic changes in adiponectin levels occur during the early neonatal period. Cord blood adiponectin levels were extremely high (71.0 +/- 21.0 microg/ml; n = 51) compared with serum levels in children and adults and positively correlated with fetal birth weights (r = 0.4; P < 0.01). No significant differences in adiponectin levels were found between female and male neonates. In addition, there was no correlation between cord adiponectin levels and maternal body mass index, cord leptin, or insulin levels. Cord adiponectin levels were significantly higher compared with maternal levels at birth (61.1 +/- 19.0 vs. 17.6 +/- 4.9 microg/ml; P < 0.001; n = 17), and no correlation was found between cord and maternal adiponectin levels. There were no significant differences between adiponectin levels at birth and 4 d postpartum (61.1 +/- 19.0 vs. 63.8 +/- 22.0 microg/ml; n = 17). These findings indicate that adiponectin in cord blood is derived from fetal and not from placental or maternal tissues. The high adiponectin levels in newborns compared with adults may be due to lack of negative feedback on adiponectin production resulting from lack of adipocyte hypertrophy, low percentage of body fat, or a different distribution of fat depots in the newborns.