BETA-1 INTEGRINS IN 3RD-TRIMESTER HUMAN PLACENTAE - NO DIFFERENTIAL EXPRESSION IN PATHOLOGICAL PREGNANCY

Integrins are a group of cell surface receptors that play important ro les in cell-cell and cell-extracellular matrix interactions. The expre ssion of trophoblast cell surface integrin subunits changes during pla cental development in normal pregnancy but the functional significance is unknown. The aim of this study was to investigate the expression o f beta 1 integrins and their extracellular matrix ligands in human pla centa and membranes in normal and pathological pregnancy using an avid in-biotin-peroxidase technique. Expression of the beta 1 integrins was similar in all study groups. Whilst there mas some heterogeneity of e xpression of specific integrin a chains this was nos characteristic of defined subject groups, variations occurring within all groups. Two d istinct trophoblast subpopulations were demonstrated in the chorion la eve according to differential expression of beta 1 integrins. Trophobl ast immediately adjacent to maternal decidua, which expressed alpha 1 rather than alpha 2, also comprised the majority of trophoblast in the basal plate; possession of the alpha 1, alpha 3, alpha 5, alpha 6 rat her than alpha 2, alpha 3, alpha 5, alpha 6 phenotype may be important in the invasive potential of trophoblast populations. The results obt ained in the present study indicate that the integrin phenotypes of th ird trimester uteroplacental tissues are similar in normal and patholo gical pregnancy, including pre-eclampsia, before and after labour.