Identification of prometalloproteinase-3 as a major protein secreted by human endometrial fibroblasts and inhibited by coculture with trophoblast cells.

To assess endometrial fibroblast-cytotrophoblast interactions, we used a coculture system allowing analysis of the potential cell morphology modifications and protein secretion variations possibly involved in endometrial invasion arrest. Stromal cells and cytotrophoblasts were isolated from endometrial biopsies and first-trimester placental villi, respectively. In our culture conditions, a 57-kDa protein that was secreted by cultured fibroblasts but was absent in the 4-day coculture medium was found to be identical to prometalloproteinase-3 (proMMP-3) through determination of amino acid sequences of NH2-terminal and internal peptides. Northern blotting analysis of endometrial fibroblast total RNA showed a 38.6% metalloproteinase-3 (MMP-3) mRNA inhibition by 4-day 10(-6) M R5020 treatment. Inhibition of proMMP-3 secretion was weak when cytotrophoblasts were cultured for 4 days in a polycarbonate membrane insert over cultured fibroblasts without possible cell contact in spite of high levels of progesterone produced by cytotrophoblasts. Furthermore, cytotrophoblasts cultured on a monolayer of endometrial fibroblasts became syncytia, and most of the fibroblasts were decidualized. The closeness of the two cell types allowed paracrine relationships that might facilitate the progesterone action. Since MMP-3 is known to activate collagenases, inhibition of its secretion by cell contact might be a mechanism of invasion arrest for trophoblast cell migration.

Immunogenetic study of couples with recurrent spontaneous abortions.

OBJECTIVES: Clinical observations suggest that genetic and immunologic disparity could be a factor in fecundity. The HLA system (HLA) is polymorphic and TLX (Trophoblast Lymphocyte Cross-Reactive), which is also polymorphic, seems to be linked to it. The immunologic hypothesis follows that excessive HLA and TLX-sharing could explain the rejection of a semi-allogenic blastocyst. Study objectives are therefore twofold; To determine whether or not there is significant HLA-sharing between spouses with unexplained recurrent spontaneous abortions (RSA) and to determine whether or not there is an association between some HLA specificities and RSA. STUDY DESIGN: The study includes only Caucasian couples that have had three successive spontaneous abortions. These were distributed in two groups: Group E: 18 couples either with known aetiology or with secondary RSA; Group U: seven couples with unexplained primary RSA; Control group C: 21 couples with at least two children and no spontaneous abortions. Tissue typing for HLA-A and B molecules was performed using serotyping methodology based on lymphocytotoxicity reaction. The different DRB1 alleles (class II) were determined by oligotyping with a non-radioactive reverse dot-blot methodology. RESULTS: Statistical comparison shows that the number of couples without shared specificity is not significantly different between the three groups for each locus independently and for the set of three. Our results show also that the allelic frequencies are not significantly different between the three groups. CONCLUSIONS: There is no higher HLA-sharing in couples with RSA than in fertile couples. Similarly, no particular HLA specificity can be associated with the RSA.