CULTURE OF SYNCYTIOTROPHOBLAST FOR THE STUDY OF HUMAN PLACENTAL-TRANSFER .2. PRODUCTION, CULTURE AND USE OF SYNCYTIOTROPHOBLAST

The conditions necessary for producing syncytical syncytiotrophoblast are examined. Tissue disaggregation conditions, culture media composit ion, different extracellular matrices and the influence of placental g estational age are all assessed. The importance of evaluating the bioc hemical and functional differentiational state of the cells is also st ressed. Evidence is summarized that syncytiotrophoblast in culture is morphologically and ultrastructurally very similar to syncytiotrophobl ast in vivo, and what is so far known biochemically is largely consist ent with what is known in vivo. Studies published to date on microvill ous membrane uptake and release and relationships with intracellular m etabolism using syncytiotrophoblast in conventional culture are outlin ed from the point of view of the advantages and potential of this mode l. The present state of development of the two-sided model is assessed , mentioning factors to be considered such as the supporting membrane to be used, accounting for passive diffusion and paracellular leak com ponents of transport and dealing with quantitative effects in kinetic studies of the presence of the supporting membrane. It is concluded th at satisfactory methods are now in place for preparing pure villous sy ncytial syncytiotrophoblast in culture from cytotrophoblast derived fr om term (but not early) placentae, suitable for studying microvillous membrane transport and relationships with intracellular metabolism. Cy totrophoblast from early gestational age placenta may require differen t conditions to form true syncytiotrophoblast. A two-sided model for s tudies of overall transfer, basal transport and basal control mechanis ms is now available and possibly with some development should be a goo d model for such investigations. (C) 1997 W. B. Saunders Company Ltd.