Infection and labor. III. Interleukin-1: a signal for the onset of parturition.
The regulatory signals responsible for the increased biosynthesis of prostaglandins during parturition have not been established. Because interleukin-1 is capable of stimulating prostaglandin production by intrauterine tissues and is an inflammatory mediator, we propose that interleukin-1 may act as a signal for the onset of human labor in the setting of intrauterine infection. The purpose of these studies was to determine interleukin-1 activity in amniotic fluid and to establish its relationship with the onset of term and preterm labor. Amniotic fluid from 182 patients was assayed for interleukin-1 activity. Cell-associated interleukin-1 activity was detected in fluid obtained in the third trimester but not in fluid obtained in the second trimester of pregnancy, suggesting a maturational event in interleukin-1 production. The factor responsible for interleukin-1 activity had biochemical characteristics of interleukin-1 alpha (estimated molecular weight of 14 kilodaltons, isoelectric point = 4.9), and its activity was blocked with an anti-interleukin-1 alpha antisera. Women in spontaneous labor at term were likely to have fluid phase interleukin-1 activity in amniotic fluid than women who were not in labor at term. Preterm labor in the setting of intraamniotic infections was associated with significant interleukin-1 activity in amniotic fluid. This bioactivity was predominantly attributable to interleukin-1 beta. A strong correlation between interleukin-1 and amniotic fluid concentrations of prostaglandin E2 and prostaglandin F2 alpha was found in women in preterm labor. These findings support the hypothesis that interleukin-1 may play a role in the initiation of preterm labor associated with intraamniotic infection.
Romero
R
R
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06510.
Brody
D T
DT
Oyarzun
E
E
Mazor
M
M
Wu
Y K
YK
Hobbins
J C
JC
Durum
S K
SK
D000653:Amniotic Fluid / Q000032:analysis; D015237:Dinoprost / Q000032:analysis; D015232:Dinoprostone / Q000032:analysis; D005260:Female; D006801:Humans; D007375:Interleukin-1 / Q000032:analysis*; D007745:Labor Onset / Q000276:immunology*; D007743:Labor, Obstetric / Q000276:immunology*; D007744:Obstetric Labor Complications / Q000276:immunology*; D007752:Obstetric Labor, Premature / Q000276:immunology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology*; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third
D007375:Interleukin-1; D015237:Dinoprost; D015232:Dinoprostone