IMMUNOREACTIVE 15-HYDROXYPROSTAGLANDIN DEHYDROGENASE (PGDH) IS REDUCED IN FETAL MEMBRANES FROM PATIENTS AT PRETERM DELIVERY IN THE PRESENCEOF INFECTION

Previously we reported that the proportion of trophoblast cells that w ere immunopositive for 15-OH prostaglandin dehydrogenase (PGDH) in the chorionic membranes was reduced in women in preterm labour without in fection, compared with women at term, but was not altered in preterm l abour patients with an underlying infective process. Subsequently, we found that PGDH activity and PGDH mRNA were significantly lower in mem branes of this latter group of patients than in women at preterm labou r without infection or at term. To resolve this issue we used immunohi stochemistry to examine the distribution and frequency of immunoreacti ve (ir)-PGDH positive cells in full-thickness fetal membranes in patie nts at preterm labour in the presence or absence of infection. Trophob last and decidual stromal cells were identified using antibodies again st cytokeratin and vimentin, respectively. There was considerable vari ation in the number of chorionic trophoblast cells that were positive for ir-PGDH, but in some patients there was little or no ir-PGDH stain ing, and this was associated with loss of trophoblast cells from the t issue. The mean intensity and number of ir-PGDH positive cells was sig nificantly lower in membranes from patients in preterm labour with inf ection than in idiopathic preterm labour at which the diagnosis of inf ection was not made. We conclude that in the setting of preterm labour with infection there may be loss of trophoblast cells from membranes, with corresponding reduction in the number of ir-PGDH positive cells. Loss of PGDH activity removes the initial step in activating primary prostaglandins, which are then able to pass unmetabolized to the decid ua and myometrium, and contribute to the stimulus to preterm birth. (C ) 1996 W. B. Saunders Company Ltd