Inhaled nitric oxide does not affect adenosine 5'-diphosphate-dependent platelet activation in infants with persistent pulmonary hypertension of the newborn.
OBJECTIVE
To investigate the effect of inhaled nitric oxide (NO) treatment in newborns with persistent pulmonary hypertension on adenosine 5'-diphosphate (ADP)-dependent platelet activation.


METHODS
After parental informed consent, infants with persistent pulmonary hypertension of the newborn were randomly assigned to receive conventional treatment (control group) or treatment with 40 parts per million of inhaled NO. Platelet activation was measured at time of entry and 30 minutes later by surface expression of P-selectin in response to increasing concentrations of the agonist ADP (0, 2, 5, 10, and 20 microM) using fluorescence-activated flow cytometry.


RESULTS
We examined 11 infants in the inhaled NO group and 13 in the control group. P-selectin expression, quantified as mean fluorescence, was not significantly different in the two groups of patients at baseline. Median percent change from baseline fluorescence was assessed using the Wilcoxon matched-pairs signed-rank test. At 30 minutes after enrollment there were no statistically significant changes from baseline fluorescence in either group of patients and at all ADP concentrations.


CONCLUSIONS
Thirty minutes of exposure to 40 ppm of inhaled NO does not inhibit ADP-dependent platelet activation as measured by surface expression of P-selectin in infants with persistent pulmonary hypertension of the newborn.
Christou
H
H
Division of Newborn Medicine, Children's Hospital, Boston, MA 02115, USA.
Magnani
B
B
Morse
D S
DS
Allred
E N
EN
Van Marter
L J
LJ
Wessel
D L
DL
Kourembanas
S
S
D000244:Adenosine Diphosphate / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D007231:Infant, Newborn; D009569:Nitric Oxide / Q000494:pharmacology* / Q000627:therapeutic use; D019007:P-Selectin / Q000097:blood; D010547:Persistent Fetal Circulation Syndrome / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology*; D015539:Platelet Activation / Q000187:drug effects*
D019007:P-Selectin; D009569:Nitric Oxide; D000244:Adenosine Diphosphate