Nitric oxide pathway adaptive changes related to intrauterine growth, gestational age at birth and mode of delivery.

S. PISANESCHI; A.M. SANCHEZ; S. GARIBALDI; L. GOGLIA; V. TOSI; S. BEGLIUOMINI; A.R. GENAZZANI; F. COCEANI; T. SIMONCINI

March 5-8, Venezia, Italy

Congreso; 13th World Congress on Human Reproduction.; 2009

The endothelium plays a crucial role in the maintenance of vascular tone and structure. The higher risk or respiratory problem in infants delivered by elective caesarean section versus vaginally born babies may be related with low level of NO and higher oxidative stress in these babies. The complex, but well coordinated mechanisms that control the onset and maintenance of labor remains unrevealed. We evaluated the role of the umbilical endothelial function related to intrauterine growth, gestational age at birth and mode of delivery, by combining the HUVEC molecular analysis with umbilical and neonatal blood S-nitrosohemoglobin, nitric oxide and asymmetric dimethylarginine. We analyzed newborns small for gestational age and restricted for growth, born at term and preterm by elective caesarean section with/out prolonged labor. The preterm delivery is associated with a decreased HUVEC nitric oxide release and an increased venous nitric oxide, related to a lower concentration of S-nitrosohemoglobin. The umbilical vein NO and SNOHb levels were significantly higher at birth in infants delivered vaginally or by caesarean section after labor versus babies born through programmed section. Opposite results were observed in arterial NO concentration and in HUVEC NO release. We propose that S-NOHb may be consumed under fetal hypoxic conditions in preterm babies and [NO_] equivalents are transferred to the umbilical vessel wall, as a compensatory response to preterm respiratory distress. In addition, we conclude that the oxidative stress experienced during the parturition may have a role in preserving the babies from respiratory problems, through the NO pathway.