Evidence for a spatial and temporal regulation of prostaglandin-endoperoxide synthase 2 expression in human amnion in term and preterm parturition.
BACKGROUND
Prostaglandin-endoperoxide synthase 2 (PTGS2) is a key enzyme involved in parturition. PTGS2 mRNA was found to be differentially expressed between placental amnion (amnion overlying the placental disc) and reflected amnion (amnion of the extraplacental chorioamniotic membranes) in term placentas.


OBJECTIVE
The aim was to evaluate the spatial and temporal regulation of PTGS2 expression in the amnion and the chorion-decidua.


METHODS
PTGS2 expression was analyzed in the amnion and chorion-decidua obtained from 32 women: term not in labor (n = 12), term in labor (n = 12), and preterm labor (n = 8), by immunoblotting and densitometry. Prostaglandin E(2) (PGE(2)) in the amnion and chorion-decidua was measured by a specific immunoassay.


RESULTS
Compared to preterm labor cases, PTGS2 expression increased at term before the onset of labor far more prominently in placental amnion (4.5-fold; P = 0.002) than in reflected amnion (1.4-fold; P = 0.007). There was a significant increase in PTGS2 expression in reflected amnion (2.9-fold; P < 0.01) but not in placental amnion with labor at term. PTGS2 expression was higher in reflected amnion than in chorion-decidua in labor at term (2.9-fold; P < 0.01). PTGS2 was barely detected in amnion and chorion-decidua with preterm labor. Expression of PGE(2) showed a good correlation with PTGS2 expression (r = 0.722; P < 0.001).


CONCLUSIONS
PTGS2 expression in the amnion shows a distinct spatial and temporal regulation. Spontaneous labor at term and pathological preterm labor clearly differ in amniotic PTGS2 and PGE(2) abundance. Our observations underscore the biological significance of the amnion and amniotic fluid in human parturition.
Perinatology Research Branch, National Institute of Child Health and Human Development/National Institutes of Health/Department of Health and Human Services, Bethesda, Maryland, 20892, and Detroit, Michigan, 48201, USA.
Deug-Chan
DC
Lee
Roberto
R
Romero
Jung-Sun
JS
Kim
Wonsuk
W
Yoo
JoonHo
J
Lee
Pooja
P
Mittal
Juan Pedro
JP
Kusanovic
Sonia S
SS
Hassan
Bo Hyun
BH
Yoon
Chong Jai
CJ
Kim
D000650:Amnion / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008954:Models, Biological; D007752:Obstetric Labor, Premature / Q000235:genetics / Q000378:metabolism; D036801:Parturition / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D011247:Pregnancy; D047929:Term Birth / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution / Q000235:genetics
D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D015232:Dinoprostone